Spin-boson dynamics A unified approach from weak to strong coupling

Annu.Rev.Phys.Chem.2000.51:129–52Copyright c2000by Annual Reviews.All rights reserved G ENERALIZED B ORN M ODELS OFM ACROMOLECULAR S OLVATION E FFECTSDonald Bashford and David A.CaseDepartment of Molecular Biology,The Scripps Research Institute,La Jolla,California 92037;e-mail:bashford@,case@Key Words solvation energy,continuum dielectricss Abstract It would often be useful in computer simulations to use a simple de-scription of solvation effects,instead of explicitly representing the individual solvent molecules.Continuum dielectric models often work well in describing the thermo-dynamic aspects of aqueous solvation,and approximations to such models that avoid the need to solve the Poisson equation are attractive because of their computational efficiency.Here we give an overview of one such approximation,the generalized Born model,which is simple and fast enough to be used for molecular dynamics simulations of proteins and nucleic acids.We discuss its strengths and weaknesses,both for its fidelity to the underlying continuum model and for its ability to replace explicit con-sideration of solvent molecules in macromolecular simulations.We focus particularly on versions of the generalized Born model that have a pair-wise analytical form,and therefore fit most naturally into conventional molecular mechanics calculations.INTRODUCTIONThere are many circumstances in molecular modeling studies where a simplified description of solvent effects has advantages over the explicit modeling of each solvent molecule.One of the most popular models,especially for water,treats the solvent as a high-dielectric continuum,interacting with charges that are em-bedded in solute molecules of lower dielectric.The solute charge distribution,and its response to the reaction field of the solvent dielectric,can be modeled either by quantum mechanics or by partial atomic charges in a molecular me-chanics description.In spite of the severity of the approximation,this model often gives a good account of equilibrium solvation energetics,and it is widely used to estimate pKs,redox potentials,and the electrostatic contributions to molec-ular solvation energies (for recent reviews,see 1–6).For molecules of arbitrary shape,the Poisson-Boltzmann (PB)equations that describe electrostatic interac-tions in a multiple-dielectric environment are typically solved by finite-difference or boundary-element numerical methods (1,7–12).These can be efficiently solved0066-426X/00/1001-0129$14.00129A n n u . 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F o r p e r s o n a l u s e o n l y .130BASHFORD¥CASEfor small molecules but may become quite expensive for proteins or nucleic acids.For example,the DelphiII program,which is a popular program that computes a finite-difference solution,takes about 25min on a 195-Mhz SGI processor to solve problems on a 1853grid with 600atoms.Obtaining derivatives with respect to atomic positions adds to the time and complexity of the calculation (13).Even though progress continues to be made in numerical solutions,and other approaches may be significantly faster,there is a clear interest in exploring more efficient,if approximate,approaches to this problem.One such simplification that has received considerable recent attention is the generalized Born (GB)approach (14,15).In this model,which is derived below,the electrostatic contribution to the free energy of solvation isG pol =−12 1−1w i ,j q i q jf GB , 1.where q i and q j are partial charges,εw is the solvent dielectric constant,andf GB is a function that interpolates between an “effective Born radius”R i ,when the distance r i j between atoms is short,and r i j itself at large distances (15).In the original model,values for R i were determined by a numerical integration proce-dure,but it has recently been shown that “pair-wise”approximations,in which R i is estimated from a sum over atom pairs,can be nearly as accurate and provide a simplified approach to energies and their derivatives (16–21).In the following sections,we present one derivation of this model and compare it to the underlying continuum dielectric model on which it is based.This is followed by a review of pair-wise parameterizations and of practical applications of GB and closely related approximations.Our emphasis is almost exclusively on the use of this approach to describe aqueous solvation of macromolecules.A comprehensive review of other applications of the GB model has recently appeared (6).GENERALIZED BORN AND RELATED APPROXIMATIONSThe underlying physical picture on which the GB approximation is based is the two-dielectric model described above.To obtain the electrostatic potential φin such a model,one should ideally solve the Poisson equation,∇[ε(r )∇φ(r )]=−4πρ(r ),2.where ρis the charge distribution,and the dielectric constant εtakes on the solute molecular dielectric constant εin in the solute interior and the exterior dielectric constant εex elsewhere.For gas phase conditions,εex =1,whereas in solvent conditions,εex =εw ,the dielectric constant of the solvent (here,water);solving Equation 2under these two conditions leads to potentials that can be denoted φsol and φvac ,respectively.The difference between these potentials is the reaction field,φreac =φsol −φvac ,and the electrostatic component of the solvation free energy isG pol =12φreac (r )ρ(r )dV , 3.A n n u . 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F o r p e r s o n a l u s e o n l y .GENERALIZED BORN MODELS 131or if the molecular charge distribution is approximated by a set of partial atomic point charges q i ,G pol =12i q i φreac (r i ). 4.In the case of a simple ion of radius a and charge q ,the potentials can be found analytically and the result is the well-known Born formula (22),G Born =−q 22a 1−1εw. 5.If we imagine a “molecule”consisting of charges q 1···q N embedded in spheres of radii a 1···a N ,and if the separation r i j between any two spheres is sufficiently large in comparison to the radii,then the solvation free energy can be given by a sum of individual Born terms,and pair-wise Coulombic terms:G pol =N i q 2i 2a i 1w −1 +12N i N j =i q i q j r i j 1w −1 , 6.where the factor (1/εw −1)appears in the pair-wise terms because the Coulombicinteractions are rescaled by the change of dielectric constant on going from vacuum to solvent.The goal of GB theory can be thought of as an effort to find a relatively simple analytical formula,resembling Equation 6,which for real molecular geometries will capture,as much as possible,the physics of the Poisson equation.The linearity of the Poisson equation (or the linearized PB equation)assures that G pol will indeed be quadratic in the charges,as both Equations 1and 6assume.However,in calculations of G pol based on direct solution of the Poisson equation,the effect of the dielectric constant is not generally restricted to the form of a prefactor,(1/εw −1),nor is it a general result that the interior dielectric constant,εin ,has no effect.With these caveats in mind,we seek a function f GB ,to be used in Equation 1,such that in the self (i =j )terms,f GB acts as an “effective Born radius,”whereas in the pair-wise terms,f GB becomes an effective interaction distance.The most common form chosen (15)isf GB (r i j )= r 2i j +R i R j exp −r 2i j /4R i R j 12,7.in which the R i are the effective Born radii of the atoms,which generally dependnot only on a i ,the intrinsic atomic radii,but also on the radii and relative positions of all other atoms.Ideally,R i should be chosen so that if one were to solve the Poisson equation for a single charge q i placed at the position of atom i ,and a dielectric boundary determined by all of the molecule’s atoms and their radii,then the self-energy of charge i in its reaction field,q i φreac (r i )/2,would be equal to −(q 2/2R i )(1−1/εw ).Obviously,this procedure per se would have no practical advantage over a direct calculation of G pol using a numerical solution of the Poisson equation.To find a more rapidly calculable approximation for the effective Born radii,we turn to a formulation of electrostatics in terms of integration over energy density.A n n u . 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F o r p e r s o n a l u s e o n l y .132BASHFORD¥CASEDerivation in Terms of Energy DensitiesIn the classical electrostatics of a linearly polarizable media (23),the work required to assemble a charge distribution can be formulated either in terms of a product of the charge distribution with the electric potential,as above,or in terms of the scalar product of the electric field E and the electric displacement D :W =12 ρ(r )φ(r )dV 8.=18π E ·D dV .9.We now introduce the essential approximation used in most forms of GB theory:that the electric displacement is Coulombic in form,and remains so even as the ex-terior dielectric is altered from 1to εw in the solvation process.In other words,the displacement due to the charge of atom i (which for convenience is here presumed to lie on the origin)isD i ≈q i r r3.10.This is called the Coulomb field approximation.In the spherically symmetric case (as in the Born formula),it is exact,but in more complex geometries,there may be substantial deviations,a point to which we turn presently.The work of placing a charge q i at the origin within a molecule whose interior dielectric constant is εin ,surrounded by a medium of dielectric constant εex and in which no other charges have yet been placed,is thenW i =18π (D /ε)·D dV ≈18π in q 2i r 4εin dV +18πex q 2i r 4εex dV .11.The electrostatic component of the solvation energy is found by taking the differ-ence in W i when εex is changed from 1.0to εw ,G pol i =−18π 1−1w ex q ir dV ,12.where the contribution due to the interior region has canceled in the subtraction.1Comparing Equation 12to the Born Formula 5or to Equations 1or 6,we conclude that the effective Born radius should beR −1i =14π ex 1r 4dV .13.1Itmay be noticed that the interior integral contained a singularity at r →0.This a con-sequence of representing the charge distribution as a set of point charges,and similar singularities appear in treatments based on the electrostatic potential.The validity of can-celing out such singularities can be demonstrated by replacement of these point charges by small charged spheres and consideration of the limit as the sphere radii shrink to zero.A n n u . 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F o r p e r s o n a l u s e o n l y .GENERALIZED BORN MODELS 133It is often convenient to rewrite this in terms of an integration over the interior region,excluding a radius a i around the origin,R −1i =a −1i −14π in ,r >a i 1r 4dV ,14.where we have used the fact that the integration of r −4over all space outside radius a is simply 4πa −1.Note that in the case of a monatomic ion,where the molecular boundary is simply the sphere of radius a i ,this equation becomes R i =a i and the Born formula is recovered exactly.The integrals in Equation 13or 14can be calculated numerically by constructing a set of concentric spherical shells around atom i and calculating the fractional area of these shells lying inside or outside the van der Waals volume of the other atoms,j =i (15),or by using a cubic integration lattice (24).Ghosh et al (25)have proposed an alternative approach,in which the Coulomb field is still used in place of the correct field,and Green’s theorem is used to convert the volume integral in Equation 14to a surface integral.At this level,the S-GB (surface-GB)model is formally identical to the model outlined above.(There are potential computational advantages in the surface integral approach,especially for large systems and for evaluating gradients,but these have not yet been exploited.)In practice,empirical short-range and long-range corrections (discussed below)are added to improve agreement with numerical Poisson theory.Solute Dielectrics Other than UnityStrictly speaking,the Coulomb field approximation assures that the internal dielec-tric constant,εin ,does not appear in GB theory;the only dielectric constants that matter are those of the solvent and the vacuum.(See the passage from Equation 11to Equation 12.)However,εin can reappear in an indirect and somewhat deceptive way,in GB-based expressions for energy as a function of solute conformation or intermolecular interaction energies.In such cases,one would like to have a poten-tial of mean force described on the hypersurface of the solute degrees of freedom.Its electrostatic component would bePMF elec =E elec ,ref + G pol (ref →sol ),15.where E elec ,ref is the electrostatic energy of the solute in some reference environ-ment that is chosen so that the calculation can be done simply,and G pol (ref →sol )is the energy of transferring the system from this reference environment to solvent.If the solute is presumed to have an internal dielectric of 1,the obvious choice of reference medium is the vacuum,where E elec ,ref can be calculated by Coulomb’s law,and the usual GB expressions for G pol can be used unchanged for G pol (ref →sol ).However,if the internal dielectric has a value εin that is different from 1,a more convenient choice is a reference medium of dielectric constant εin ,so that Coulomb’s law can again be used.In this case,all occurrencesA n n u . 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F o r p e r s o n a l u s e o n l y .134BASHFORD¥CASEof (1−1/εw )in the GB theory expressions are replaced by (1/εin −1/εw ).The resulting expression for the electrostatic potential of mean force isPMF elec =12 i =j q i q j in r i j −12 i ,j 1in −1wq i q jf GB i j 16.(compare with Equation 1).At long distances,where f GB goes to r i j ,the εin de-pendence disappears.It should be emphasized that εin appears in these formulaenot so much because it is the internal dielectric constant as because it is the ex-ternal dielectric constant of the reference environment.In particular,GB theory,because of its Coulomb field approximation,and in contrast to Poisson-equation theory,cannot capture the tendency of solvation to increase the dipole moment of a dipolar solute,thus enhancing its solubility,through the use of an internal dielectric constant.Of course,such effects can be captured by methods that ex-plicitly couple some other theory of solute polarizability to GB theory,e.g.though quantum mechanical descriptions of the solute (6).Incorporation of Salt EffectsGB models have not traditionally considered salt effects,but the model can be extended to low salt concentrations at the Debye-Huckel level by the following arguments (21).The basic idea of the GB approach can be viewed as an inter-polation formula between analytical solutions for a single sphere and for widely separated spheres.For the latter,the solvation contribution in the Poisson model becomesG pol =− 1−e −κr i j wq i q jr i j ,17.where κis the Debye-H¨u ckel screening parameter.The first term removes the gas-phase interaction energy,and the second term replaces it with a screened Coulombpotential.For a single spherical ion,the result is (26,27)G pol =−12 1−1εwq 2a −q 2κ2εw (1+κb ),18.where a is the radius of the sphere and b is the radial distance to which salt ionsare excluded,so that b −a is the ion-exclusion radius.To a close extent,these two limits can be obtained by the simple substitution1−1w → 1−e −κf GBw19.in Equation 1.This reduces directly to Equation 17for large distances,and thesalt-dependent terms become,as r i j goes to zero,−q 2i κ2εw 1+12κR i 20.A n n u . 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F o r p e r s o n a l u s e o n l y .GENERALIZED BORN MODELS 135through terms in κ2.To terms linear in κ,Equations 20and 18agree,but the quadratic terms differ by the replacement of b with 1/2(R i ).In practice,Equation 19gives salt effects that are slightly larger than those predicted by finite-difference linearized PB calculations,but which are strongly correlated with them.One likely reason is that the GB model outlined here does not have the concept of an ion-exclusion radius and,hence,tends to overestimate salt effects (compared with the usual PB model)by allowing counterions to approach more closely to the solute than they should.A simple ad hoc modification that leads to acceptable results can be obtained by a simple scaling of κby 0.73in Equation 19(21).Figure 1compares linearized PB and GB estimates of the effect of monovalent added salt on the solvation energy of a 10-bp DNA duplex.The GB model is clearly capturing most of the behavior of linearized PB,especially at low salt concentrations.It is worth emphasizing that the linearized PB model itself is an imperfect model for salt effects (28),so that Equation 20should only be viewed as a rough approximation;it does,nonetheless,introduce the exponential screening of long-range Coulomb interactions,which is one of the hallmarks of salt effects.Limitations and Variations of the GB ModelThe crux of the GB approximation for the self-energy terms and effective radii is the Coulomb field approximation,Equation 10,and this is also the main source of its deviation from solvation energies calculated using solutions of thePoissonFigure 1Difference in the solvation energy at finite and zero added salt for a 10-bp DNA duplex,calculated by numerical solutions to the linearized PB model,and from Equation 38.(Data from Reference 21.)A n n u . 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F o r p e r s o n a l u s e o n l y .136BASHFORD¥CASEequation.In general,the electric displacement generated by a charge q i located at a position r i within the low dielectric cavity of the solute will consist of a Coulomb field and a reaction field component D reac ,the latter being a consequence of the nonuniformity of the dielectric environment.The reaction field contains no Coulombic singularities within the molecular interior and is usually fairly smoothly varying within this region.If the dielectric boundary between solvent and solute is sharp,which is the usual assumption,then D reac can be thought of as arising from an induced surface charge density on the dielectric boundary.In spherically symmetric cases,such as the case analyzed in the original Born theory,D is given exactly by the Coulomb field (D reac is zero),and GB solvation goes over into Poisson-equation solvation.Schaefer &Froemmel (29)have an-alyzed deviations from the Coulomb-field approximation for the case of charges at arbitrary positions within a spherical dielectric boundary,a case for which an-alytical solutions of the Poisson equation are available (26).They found that the Coulomb field approximation leads to significant errors in both self-energies and in the screening of charge-charge interactions,and they proposed an image-charge approximation for D reac that is very successful in recovering the energetic behavior of the exact Poisson model.Some additional quantitative sense of the limitations of the Coulomb field ap-proximation can be gained by considering the case of a charge near a planar dielectric boundary (Figure 2).This can be thought of as the infinite-radius limit of the situation where a charge is a distance d below the surface of a spherical macromolecule with a large radius (R d )and a dielectric constant εin ,and the macromolecule is transferred from an external medium of dielectric constant εin to a medium of dielectric constant εw .The electrostatic potential can be found exactly by the method of images (23).φz >0=q εin r 1+q εin r 2φz <0=q ex r 1,21.whereq =−qεex −εin ex in q =q 2εexex in .22.The reaction field in the z >0region corresponding to a change of εex from εin to εw isφreac =q εin r 2=−q εw −εin εw +εin1εin r 2,23.A n n u . 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F o r p e r s o n a l u s e o n l y .GENERALIZED BORN MODELS137Figure 2A point charge q near a dielectric interface at z =0.The dielectric constant is εin or εex in the positive or negative z regions,respectively.The potential on the +z side is a sum of the Coulomb potential of the real charge q at z =d ,and an image charge q at z =−d .The potential on the −z side is the Coulomb potential of an image charge q at z =d .The distances of an arbitrary point r from the z =d and z =−d charge locations are denoted as r 1and r 2,respectively.where the r 1term has canceled in the subtraction of the potential in the εex =εin case from the potential in the εex =εw case.The electrostatic solvation energy can be found using Equation 4,G pol (exact )=−q 24d εw −εin εin (εw +εin )=−q 24d 1εin −1εw11+εin /εw .24.The corresponding formula for the solvation energy according to the Coulomb-field approximation and an integration of the energy density difference over the“exterior”(z <0)region can be obtained using Equation 12:G pol (Coulomb )= 1in −1w 18πz <0q 2r 2=−q 28d 1in −1w .25.Note that in the usual case where εw εin ,the magnitude of G pol is underesti-mated by a factor of almost 2compared with the exact expression,Equation 24,although the form of the dielectric-constant dependence,a factor of (1/εin −1/εw ),is approximately correct.This suggests that for charges buried somewhat below the surface of large macromolecules,the |W i |of Equation 11may be underestimated,and thus the effective Born radii overestimated because of the Coulomb-field ap-proximation.Of course the methods of approximating density integrals (such asA n n u . 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F o r p e r s o n a l u s e o n l y .138BASHFORD¥CASEthe pair-wise descreening approximation decribed below)will also affect the re-sults.On the other hand,most of the solvation energy of a macromolecule will be due to charged or highly polar groups that protrude into solvent,and for these groups,GB theory may be expected to work nearly as well as for analogous groups in small molecules.Luo et al (30)have also examined errors arising from replacing the true field with a Coulomb approximation.Essentially,they assume that E ≈E vac /d F ,where E vac is the vacuum Coulomb field and d F is a screening parameter having different values in the interior region or exterior regions.In the centrosymmetric case,d F is identical to the dielectric constant,but for more general shapes,it is a parameter to be optimized to provide realistic solvation energies.This leads toG pol =−18πεw −1d Fex E 2vac dV .26.Noting that in the Coulomb field approximation D =E vac ,this expression is similarto Equation 12with (1−1/εw )replaced by (εw −1)/d F .Its other difference from GB theory is that this expression is used for the entire solvation energy,implicitly including charge-charge interactions terms rather than using a formula such as Equation 7.On a number of test cases,it was found to give good agreement with Poisson calculations,but the numerical integration required had roughly the same computational cost as solving the Poisson equation numerically.The limitations of both the density integration methods and the Coulomb field approximation are also addressed in the electrostatic component of the SEED method for docking small molecular fragments to a macromolecular receptor (31).The desolvation of the receptor by the low dielectric of the ligand is taken to be the integral of D 2/(8π)over the ligand volume,and D is assumed not to change on ligand binding,as in conventional GB theory.The integration is done numerically using a cubic lattice,and the user can choose whether to estimate D by the Coulomb field approximation,as in GB theory,or to calculate it by a finite difference solution of the Poisson equation for the ligand-free receptor.In its use of a D obtained by solving the Poisson equation,this method is similar in spirit to the SEDO approximation described below,except that the latter is based on solvation energy density rather than D 2.Solvation Energy DensityIn Equation 12,the solvation energy is expressed as the volume integral of an energy density that is zero within the solute volume,so that the integral need only run over the solvent volume.This could be thought of as a solvation energy density,but it is only by virtue of the Coulomb field approximation that it falls to zero in the solute region.It is possible to give a more rigorous definition of solvation energy density that does not depend on approximations (32).In classical continuum electrostatics,an important problem is to find the energy change caused by placing a dielectricA n n u . 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F o r p e r s o n a l u s e o n l y .object within some volume,in the electric field of a fixed set of charges outside that volume.This is essentially the same as the present solvation problem:We seek the change of energy associated with changing the dielectric constant of the region outside the molecule V ex ,from εvac to εw ,in the presence of the atomic partial charges,which remain fixed in the molecular interior.Denoting the electric field and displacement before the dielectric alteration as E vac and D vac ,and after the alteration as E sol and D sol ,respectively,the energy change isG pol =18π (E sol ·D sol −E vac ·D vac )dV ,27.where the volume integration runs over all space.It can be shown (23)that Equation 27can be transformed intoG pol =18π (E sol ·D vac −D sol ·E vac )dV ing D =εE ,it can be seen that the integrand falls to zero in the molecular interior because the dielectric constant there does not change (i.e.E sol ·εin E vac −εin E sol ·E vac =0).One can then writeG pol =exS (r )dV ,29.where the integral runs only over the exterior region,and S is the solvation energydensity,defined byS =18π(E sol ·D vac −D sol ·E vac ).30.No approximations have been introduced up until this point,and Equations 29and 30are fully equivalent to Equation 3.Of course,if one introduces the Coulomb field approximation,Equation 10,into the expression for S ,the GB theory expression for self energies is obtained.A different approximation based on S and oriented toward estimating desol-vation effects in intermolecular interactions has recently been proposed by Arora &Bashford (32).Suppose one would like to calculate the effect of the approach of a second molecule on the solvation energy of the first molecule.The effect of the low dielectric of the second molecule on the solvation energy density S of the first is twofold.First,S will go to zero in the interior of the second molecule,in other words a portion of S will be occluded.Second,in the solvent region near the second molecule,there will be some rearrangement of S .The approximation is to include the first effect but neglect the second.This means that one can precalculate S by solving the Poisson equation and differentiating the potential to obtain the field and displacement in both vacuum and solvent,for the first molecule alone.Then the desolvation effect of a second molecule can be obtained byG desol =−mol 2S mol 1dV .31.A n n u . 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表面等离子共振技术特点
表面等离子共振技术（SurfacePlasmonResonance，SPR）是一种用于研究生物分子相互作用的强大技术。

该技术基于表面等离子体共振现象，利用特殊的传感器芯片和检测系统，可以实现实时监测生物分子相互作用的动态过程，如蛋白质-蛋白质、蛋白质-核酸、受体-配体等分子相互作用。

SPR技术具有以下特点：
1. 实时性：SPR技术可以实时监测生物分子相互作用的动态过程，无需标记，避免了标记分子对样品的影响。

2. 灵敏度：SPR技术具有极高的灵敏度，可以检测到非常低浓度的样品，一般可达到10-9mol/L级别。

3. 选择性：SPR技术可以实现对生物分子特异性的检测，可以区分不同的生物分子，并且可以实现对多个生物分子的同时检测。

4. 高通量：SPR技术可以实现高通量的样品检测，同时检测多个生物分子，提高实验效率。

5. 简便易用：SPR技术操作简便，不需要复杂的样品制备和处理步骤，适用于不同的生物样品。

由于SPR技术具有以上特点，已经广泛应用于药物筛选、生物分子互作机制研究、生物传感器等领域，成为生物分子研究和开发的重要手段。

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J. Chem. Chem. Eng. 11 (2017) 55-59doi: 10.17265/1934-7375/2017.02.003Spin-Boson and Spin-Fermion Topological Model of ConsciousnessAibassov Yerkin1, Yemelyanova Valentina1, Nakisbekov Narymzhan1, Alzhan Bakhytzhan1 and Savizky Ruben21. Research Institute of New Chemical Technologies and Materials, Kazakh National University Al-Farabi, Almaty 005012, Kazakhstan2. Columbia University, 3000 Broadway, New York, NY, 10027, USAAbstract: The authors propose a new approach to the theory of spin-boson and spin-fermion topological model of consciousness. The authors will offer a common mechanism of spin-boson and spin-fermion topological model of consciousness.Key words: Spin-boson, spin-fermion, topology, model of consciousness, magnetic field.1. IntroductionRecently, much attention is removed study of theory of consciousness [1-5]. All processes in the human brain occur in the form of electromagnetic processes. Therefore, it was interesting to see consciousness in terms of spin-boson and spin-fermion topological model.The aim is to study the spin-boson and spin-fermion topological model of consciousness.The novelty of the work lies in the fact that the authors have proposed a new mechanism of spin-boson and spin-fermion topological model of work of consciousness.2. TheoryNeuronal membrane saturated carrier spin nuclei such as 1H, 13C and 31P [1, 2]. Neuronal membrane are the matrix of the brain electrical activity and play a vital role in the normal functions of the brain and conscious of their basic molecular components are phospholipids, proteins and cholesterol. Each phospholipid contains 1% 31P, 1.8% 13C and over 60% 1H lipid chain. Neuronal membrane proteins such as ion channels and receptors neural transmittersCorresponding author: Aibassov Yerkin, professor, research field: metal organic chemistry of uranium and thorium, As, Sb and Bi. also contain large clusters spin-containing nuclei. Therefore, they are firmly convinced that the nature of the spin quantum used in the construction of the conscious mind. They suggested within neurobiology that perturbation anesthetics oxygen nerve pathwaysin both membrane proteins and may play a general anesthesia. Each O2 comprises two unpaired valence electrons strongly paramagnetic and at the same time as the chemically reactive bi-radical. It is able to produce large pulsed magnetic field along its path of diffusing. Paramagnetic O2 are the only breed can be found in large quantities in the brain to the same enzyme producing nitric oxide (NO). O2 is one of the main components for energy production in the central nervous system.NO is unstable free radical with an unpaired electron and one recently discovered a small neural transmitter, well known in the chemistry of spin-field concentrated on the study of free radical-mediated chemical reactions in which very small magnetic energy conversion can change the non-equilibrium spin process. Thus, O2 and NO can serve as catalysts in a spin-consciousness associated with neuronal biochemical reactions such as the double paths reaction initiated by free radicals.3. Results and DiscussionThey present the following Postulates: (a)All Rights Reserved.Spin-Boson and Spin-Fermion Topological Model of Consciousness 56Consciousness is intrinsically connected to quantum spin; (b) The mind-pixels of the brain are comprised of the nuclear spins distributed in the neural membranes and proteins, the pixel-activating agents are comprised of biologically available paramagnetic species such as O2 and NO, and the neural memories are comprised of all possible entangled quantum states of the mind-pixels; (c) Action potential modulations of nuclear spin interactions input information to the mind pixels and spin chemistry is the output circuit to classical neural activities; and (d) Consciousness emerges from the collapses of those entangled quantum states which are able to survive decoherence, said collapses are contextual, irreversible and non-computable and the unity of consciousness is achieved through quantum entanglement of the mind-pixels.In Postulate (a), the relationships between quantum spin and consciousness are defined based on the fact that spin is the origin of quantum effects in both Bohm and Hestenes quantum formulism and a fundamental quantum process associated with the structure of space-time.In Postulate (b), they specify that the nuclear spins in both neural membranes and neural proteins serve as the mind-pixels and propose that biologically available paramagnetic species such as O2 and NO are the mind-pixel activating agents. The authors also propose that neural memories are comprised of all possible entangled quantum states of mind-pixels.In Postulate (c), they propose the input and output circuits for the mind-pixels. As shown in a separate paper, the strength and anisotropies of nuclear spin interactions through J-couplings and dipolar couplings are modulated by action potentials. Thus, the neural spike trains can directly input information into the mind-pixels made of neural membrane nuclear spins. Further, spin chemistry can serve as the bridge to the classical neural activity since biochemical reactions mediated by free radicals are very sensitive to small changes of magnetic energies.In Postulate (d), they propose how conscious experience emerges. Thus, they adopt a quantum state collapsing scheme from which conscious experience emerges as a set of collapses of the decoherence-resistant entangled quantum states. They further theorize that the unity of consciousness is achieved through quantum entanglements of these mind-pixels.3.1 Spin-Boson and Spin-Fermion Model of ConsciousnessBosons, unlike fermions obey Bose-Einstein, who admits to a single quantum state could be an unlimited number of identical particles. Systems of many bosons described symmetric with respect to permutations of the particle wave functions.Bosons differ from fermions, which obey Fermi-Dirac statistics. Two or more identical fermions cannot occupy the same quantum state (Pauli exclusion principle).Since bosons with the same energy can occupy the same place in space, bosons are often force carrier particles. Fermions are usually associated with matter. Fermions, unlike bosons, obey Fermi-Dirac statistics:in the same quantum state can be no more than one particle (Pauli exclusion principle).3.2 Topological Model of ConsciousnessIt is known that the topological phase transition Kosterlitz-Thouless-phase transition in a two-dimensional XY-model. This transition is from the bound pairs of vortex-antivortex at low temperatures ina state with vortices and unpaired antivortices at a certain critical temperature.XY-model—a two-dimensional vector spin model which has symmetry U (1). For this system is not expected to have a normal phase transition of the second order. This is because the system is waiting forthe ordered phase that is destroyed by transverse vibrations, i.e. the Goldstone modes (see. Goldstone boson) associated with the breach of the continuousAll Rights Reserved.Spin-Boson and Spin-Fermion Topological Model of Consciousness 57Fig. 1 Symmetric wavefunction for a (bosonic) 2-particle state in an infinite square well potential.All Rights Reserved.Fig. 2 Antisymmetric wavefunction for a (fermionic) 2-particle state in an infinite square well potential.Spin-Boson and Spin-Fermion Topological Model of Consciousness58(a) (b)Fig. 3 Schematic image of a vortex (a) and antivortex (b) in the example of a planar magnetic material (arrows-vectors of the spin magnetic moments).symmetry, which logarithmically diverge with increasing system size. This is a special case of Theorem Mermin- Wagner for spin systems.Fig. 3 shows a schematic image of a vortex (a) and antivortex (b) in the example of a planar magnetic material (arrows - vectors of the spin magnetic moments).Thus, the topology does not depend on the measurement of distances, it is so powerful. The same theorems are applicable to any complex symptom, regardless of its length or belonging to a particular species.4. ConclusionsIn conclusion, the authors have presented an alternative model of consciousness in which the unpaired electron spins are playing a central role as the mind pixels and unity of mind is achieved interweaving these mental pixels.The authors hypothesized that these entangled electron spin states can be formed by the action potential modulated exchange and dipolar interactions, plus O2 and NO drive activations and survive rapid decoherence by quantum Zeno effects or decoherence-free spaces. Further, the authors have assumed that the collective electron spin dynamics associated with these collapses can have effects through the spin on the classic chemistry of neural activity, thereby affecting the neural networks of the brain. Our proposals involve the expansion of the associative neural coding of memories dynamic structures of neuronal membranes and proteins. Therefore, in our electron spin based on the model of the neural substrates of consciousness consists of the following functions: (a) electronic spin networks embedded in neuronal membranes and proteins, which serve as “crazy” screen with unpaired electron spins as pixels, (b) the nerve membrane and the proteins themselves, which serve as templates for the mind and nervous screen memories; and (c) free O2 and NO, which serve as agents pixel activating.Thus, the novelty of our work is that we were the first to propose that the electromagnetic field and free radicals have a great influence on the mind.Thus, the authors have proposed a possible mechanism of the free radical O2 and N2O in the consciousness.References[1]Hu, H. P., and Wu, M. X. 2006. “Nonlocal Effects ofChemical Substances on the Brain Produced ThroughQuantum Entanglement.” Progress in Physics 3: 20-6. [2]Hu, H. P., and Wu, M. X. 2006 “Photon InducedNon-local Effects of General Anaesthetics on the Brain.”Neuro Quantology 4 (1): 17-31. All Rights Reserved.Spin-Boson and Spin-Fermion Topological Model of Consciousness 59[3]Likhtenshtein, G. I. 1974. Spin labeling methods inmolecular biology. John Wiley and Sons; London, New York, Sydney, Toronto.[4]Likhtenshtein, G. I., Yamauchi, J., Nakatsuji, S., Smirnov,A., and Tamura, R. 2008. Nitroxides: Applications inChemistry, Biomedicine, and Materials Science. Cinii: Wiley.[5]Aibassov, Y., Yemelyanova, V., and Savizky, R. 2016.“Magnetic Effects in Brain Chemistry.” Journal of Chemistry and Chemical Engineering 10: 103-8.All Rights Reserved.。

专利名称：Spin-coating method, determination methodfor spin-coating condition and mask blank发明人：Hideo Kobayashi,Takao Higuchi申请号：US10405505申请日：20030403公开号：US07195845B2公开日：20070327专利内容由知识产权出版社提供专利附图：摘要：A spin-coating method according to the present invention includes a uniforming step of rotating a substrate at a predetermined main rotation speed for a predetermined main rotation time so as to primarily make a resist film thickness uniform, and asubsequent drying step of rotating the substrate at a predetermined drying rotation speed for a predetermined drying rotation time so as to primarily dry the uniform resist film. In the present invention, a contour map, for example, of film thickness uniformity within an effective region (critical area) shown in FIG. A is determined (generated), and resist-coating is performed by selecting a condition within the optimum region in this contour map in which the film thickness uniformity (within an effective region) can be the maximum, or within the region in which the film thickness uniformity (within an effective region) can be high enough for a desirably specified.申请人：Hideo Kobayashi,Takao Higuchi地址：Tokyo JP,Tokyo JP国籍：JP,JP代理机构：Sughrue Mion, PLLC更多信息请下载全文后查看。

Espoo Feb2004'$BEYOND MOLECULAR DYNAMICSHerman J.C.BerendsenBiophysical Chemistry,University of Groningen,the NetherlandsGroningen Institute for Biosciences and Biotechnology(GBB)CSC,EspooLecture nr4,Thursday,5Februari,2004Molecular dynamics with atomic details is limited to time scales in the order of100ns.Events that are in micro-or millisecond range and beyond,as well as systemsizes beyond100,000particles,call for methods to simplify the system.The key is to reduce the number of degrees of freedom.Thefirst task is to define important degrees of freedom.The’unimportant’degrees of freedom must be averaged-out in such a way that the thermodynamic and long time-scale propertiesare preserved.The reduction of degrees of freedom depends on the problem one wishes to solve.One approach is the use of superatoms,lumping several atoms into one interactionunit.The interactions change into potentials of mean force,and the omitted de-grees of freedom are replaced by noise and friction.On an even coarser scale onemay lump many particles together and describe the behavior in terms of densitiesrather than positions.On a mesoscopic(i.e.,nanometer to micrometer)scale,thefluctuations are still important,but on a macroscopic scale they become negligibleand the Navier-Stokes equations of continuumfluid dynamics emerge.A modern development is to handle the continuum equations with particles(DPD:dissipative particle dynamics).'$ Espoo Feb2004 REDUCED SYSTEM DYNAMICSSeparate relevant d.o.f.rand irrelevant d.o.f.rForce on r :part correlated with positions rpart correlated with velocities˙rrest is’noise’,not correlated with positions or velocities of primed par-ticles.F i(t)=−∂V mf∂r i+F frictioni+F i(t)noiseF frictioni(t)is a function of v j(t−τ).F i(t)noise=R i(t)withR i(t) =0v j(t)R i(t+τ) =0(τ>0)R(t)is characterized by stochastic properties:•probability distribution w(R i)dR i•correlation function R i(t)R j(t+τ)Projection operator technique(Kubo and Mori;Zwanzig)give ele-gant framework to describe relation between friction and noise[Van Kampen in Stochastic Processes in Physics and Chemistry(1981):“This equation is exact but misses the point.The distribution cannot be determined without solving the original equation...”)]'$ Espoo Feb2004 POTENTIAL OF MEAN FORCE-1Requirement:Preserve thermodynamics!Helmholtz free energy A:A=−k B T ln QQ=ce−βV(r)d rDefine a reaction coordinateξ(may be more than one dimension).Sep-arate integration over the reaction coordinate from the integral in Q:Q=cdξd r e−βV(r)δ(ξ(r)−ξ)Define potential of mean force V mf(ξ)asV mf(ξ)=−k B T lncd r e−βV(r)δ(ξ(r)−ξ),so thatQ=e−βV mf(ξ)dξandA=−k B T lne−βV mf(ξ)dξNote that the potential of mean force is an integral over multidimensional hyperspace.It is generally not possible to evaluate such integrals from simulations.As we shall see,it will be possible to evaluate derivatives of V mf from ensemble averages.Therefore we shall be able to compute V mf by integration over multiple simulation results,up to an unknown additive constant.'$ Espoo Feb 2004 POTENTIAL OF MEAN FORCE-2To simplify,look at cartesian coordinates.ξ=r .So r are the impor-tant coordinates,and r are the unimportant coordinates.How can we determine the PMF from simulations?Let us perform a simulation in which r is constrained,while r is freeto move.V mf(r )=−k B T lnce−βV(r ,r )d r∂V mf(r )∂r i =∂V(r ,r )∂r ie−βV(r ,r )d re−βV(r r )d r=∂V(r ,r )∂r i= F c i .Derivative of potential of mean force is the ensemble-averaged constraint force(cartesian).The constraint force follows from the coordinate resetting in constraint dynamics.(This is still true in more complex’reaction coordinates’,but there are small metric tensor corrections)'$ Espoo Feb2004DIFFUSION COEFFICIENTHow to determine the diffusion constant from constrained simulations? Determinefluctuation of constraint force∆F c(t)=F c(t)− F c . Fluctuation-dissipation theorem:∆F c(0)∆F c(t) =k B Tζ(t)ζ= ∞ζ(t)dtD=k B T ζHenceD=(k B T)2∞∆F c(0)∆F c(t) dt'$ Espoo Feb 2004LANGEVIN DYNAMICS-1General form of friction force:approximated by linear response in time,linear in velocities:F fr i(t)=m ij tγij(τ)v j(t−τ)dτThis gives(in cartesian coordinates)the generalized Langevin equation:m i d v idt=−∂V mf∂r i−m ijtγij(τ)v j(t−τ)dτ+R i(t)If a constrained dynamics is carried out with r constant(hence v =0), then the’measured’force on i approximates a representation of R i(t). So one can determine an approximation to the noise correlation functionC R ij(τ)= R i(t)R j(t+τ).(assumption:motion of r that determines R(t)is fast compared to the motion of r )There is a relation between friction and noise.Espoo Feb2004'$ LANGEVIN DYNAMICS-2Relation between friction and noiseAverage total energy should be conserved(averaged over time scale large compared to noise correlation time)•Systematic force is conservative(change in kinetic energy cancelschange in V mf)•Frictional force is dissipative:decreases kinetic energy•Stochastic force has infirst order no effect since v j(t)R i(t+τ) =0.In second order it increases the kinetic energy.The cooling by friction should cancel the heating by noise(fluctuation-dissipation theorem).This leads toR(0)R(t) =k B T mγ(t)'$ Espoo Feb 2004LANGEVIN APPROXIMATIONS(write m iγij=ζij)Generalized Langevinm i˙v i(t)=−∂V mf∂x i−jtζij(τ)v j(t−τ)dτ+R i(t)withR i(0)R j(t) =k B Tζji(t) includes coupling(space)and memory(time). Simple Langevin with hydrodynamic couplingm i˙v i(t)=−∂V mf∂x i−jζij v j(t)+R i(t)withR i(0)R j(t) =2k B Tζjiδ(t) includes coupling(space),but no memory. Simple Langevinm i˙v i(t)=−∂V mf∂x i−ζi v i(t)+R i(t)withR i(0)R j(t) =2k B Tζiδ(t)δij includes neither coupling nor memory.'$ Espoo Feb2004BROWNIAN DYNAMICS-1If systematic force does not change much on the time scale of the ve-locity correlation function,we can average over a time∆t>τc.The average acceleration becomes small and can be neglected(non-inertial dynamics):0≈F i(x)−jζij v j(t)+R iwithR i= t+∆ttR(t )dtR i(0)R j(t) =2k B Tζjiδ(t)Be aware that the average acceleration is not zero if there is a cooperative motion with large massHence v j(t)can be solved from matrix equationζv=F+R(t)Solve in time steps∆tRandom force R i withR i =0R i R j =2k B Tζji∆tR i and R j are correlated random numbers,chosen from bivariate gaus-sian distributions.'$ Espoo Feb2004BROWNIAN DYNAMICS-2Without hydrodynamic coupling:v i=F iζi+r ir i is random number chosen from(gaussian)distribution with variance 2k B T∆t/ζi.x i(t+∆t)=x i(t)+v i∆tVelocity can be eliminated.Write D=k B T/ζ(diffusion constant) yields Brownian dynamicsx(t+∆t)=x(t)+Dk B TF(t)∆t+r(t)r =0r2 =2D∆tF must assumed to be constant during∆t.The longer∆t,the smaller the noise.For slow processes in macroscopic times the noise goes to zero.Espoo Feb2004'$ REDUCED PARTICLE DYNAMICSSuperatom approachLump a number of atoms together into one particle(e.g.10monomersof a homopolymer).Design forcefield for those superatoms including bonding and nonbonding terms.For polymer:•soft harmonic spring between particles,representing Gaussian distri-bution of superatom-distance distributions•harmonic angular term in chain,representing stiffness•Lennard-Jones type interactions between particles•solvent:LJ particleDerive parameters from•experimental data(density,heat of vaporization,solubility,surfacetension,...,•atomic simulations of small system(radius of gyration,end-to-enddistance distribution,radial distribution functions,....Perform normal Molecular Dynamics.Adding friction and noise hasinfluence on dynamics,but is not needed for equilibrium properties. Example:Nielsen et al.,J.Chem.Phys.119(2003)2043.Espoo Feb2004'$DPDWe can also describe the space and time-dependent densities as the im-portant variables(e.g.described on a grid of points),and consider all detailed degrees of freedom as unimportant.This leadsfirst to meso-scopic dynamics(still including noise),and for even coarser averagingto the macroscopic Navier-Stokes equation.The Navier-Stokes equation is normally solved on a grid of points. Dissipative Particle Dynamics attempts to solve the Navier-Stokes equations using an ensemble of special particles.Originally proposed by Hoogerbrugge and Koelman,Europhys.Lett.19 (1992)155.Improved by Espa˜n ol,Warren,Flekkoy,Coveney.See article by Espa˜n ol in SIMU Newsletter Issue4,Chapter III,http://simu.ulb.ac.be/newsletters/N4III.pdf。

视野VISION 创新 INNOVATION仿 生胶原蛋白支架可诱导肺组织原位再生●创新点肺组织结构非常复杂，一旦发生损伤就很难进行自我修复。

例如，肺泡毛细血管膜屏障被破坏后会引起肺部水肿、炎症以及纤维化等，这会进一步导致肺部微环境紊乱、再生困难。

因此，对于严重的急性肺损伤，原位修复是一个巨大的挑战。

目前，肺移植术是有效的治疗方法，但面临供体来源有限以及免疫排斥等风险，限制了其临床应用。

人工肺植入技术是一种新兴的替代策略，但如何在人工肺支架中重建肺组织再生的微环境仍是一个挑战。

利用再生医学技术促进肺组织再生是当前的研究热点。

最近，中国科学院遗传与发育生物学研究所戴建武研究员所带领的再生医学研究团队构建了一种智能的胶原蛋白支架，首次在仿生支架材料的指导下进行肺再生研究，并证实该支架能促进肺组织原位再生。

●方法和结果研究人员采用组织工程的策略来研究肺组织的再生。

首先，他们制备了一种与天然肺组织组成、表面结构、孔径、孔隙率和力学特性类似的三维多孔胶原蛋白支架，该仿生支架具备良好的生物相容性和生物降解性。

然后，他们又构建一个包含胶原蛋白结合结构域（CBD）和肝细胞生长因子（HGF）的融合蛋白,该融合蛋白可特异性结合三维胶原蛋白支架，并在体内外持续缓释能改善肺再生微环境的HGF。

基于此策略，研究人员开发出了高效的人工肺再生微环境系统。

最后，研究团队构建了大鼠右肺中叶部分切除模型，并将该仿生支架植入残留的肺组织边缘，发现该支架能够对损伤的肺组织进行有效的保护和修复。

研究结果显示，三维仿生胶原蛋白支架能够抑制炎症和纤维化，促进急性肺损伤后损伤区域的恢复、肺泡再生和血管生成。

仿生支架的多孔结构一方面起到分隔作用，另一方面为细胞的黏附提供有效支撑。

在移植早期，CBD-HGF 一方面可诱导宿主血管内皮细胞的迁移、增殖，从而促进微血管的形成；另一方面还可以促进内源性的肺泡前体细胞进入支架，形成类肺泡样结构，最终促进支架内功能性肺泡样结构的再生以及残肺总体形态和功能的恢复。

对于动态接触角，人们有多种状态定义：其一，对于让处于非平衡状态的液滴在固体表面上自由铺展，动态接触角又分为前进角和后退角，前进角是液体在未被润湿过的固体表面进行铺展润湿，后退角是液体在已被润湿过的固体表面进行铺展，测试前进后退角是针对于疏水材料，亲水材料测试无意义。

其二，液体在固体表面接触角随时间变化而变化的过程，也是动态接触角。

谈起接触角，一定避不开的牌子就是百欧林，这个瑞典的老牌子。

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第53卷第8期表面技术2024年4月SURFACE TECHNOLOGY·133·基于自转一阶非连续式微球双平盘研磨的运动学分析与实验研究吕迅1,2*，李媛媛1，欧阳洋1，焦荣辉1，王君1，杨雨泽1（1.浙江工业大学 机械工程学院，杭州 310023；2.新昌浙江工业大学科学技术研究院，浙江 绍兴 312500）摘要：目的分析不同研磨压力、下研磨盘转速、保持架偏心距和固着磨料粒度对微球精度的影响，确定自转一阶非连续式双平面研磨方式在加工GCr15轴承钢球时的最优研磨参数，提高微球的形状精度和表面质量。

方法首先对自转一阶非连续式双平盘研磨方式微球进行运动学分析，引入滑动比衡量微球在不同摩擦因数区域的运动状态，建立自转一阶非连续式双平盘研磨方式下的微球轨迹仿真模型，利用MATLAB对研磨轨迹进行仿真，分析滑动比对研磨轨迹包络情况的影响。

搭建自转一阶非连续式微球双平面研磨方式的实验平台，采用单因素实验分析主要研磨参数对微球精度的影响，得到考虑圆度和表面粗糙度的最优参数组合。

结果实验结果表明，在研磨压力为0.10 N、下研磨盘转速为20 r/min、保持架偏心距为90 mm、固着磨料粒度为3000目时，微球圆度由研磨前的1.14 μm下降至0.25 μm，表面粗糙度由0.129 1 μm下降至0.029 0 μm。

结论在自转一阶非连续式微球双平盘研磨方式下，微球自转轴方位角发生突变，使研磨轨迹全覆盖在球坯表面。

随着研磨压力、下研磨盘转速、保持架偏心距的增大，微球圆度和表面粗糙度呈现先降低后升高的趋势。

随着研磨压力与下研磨盘转速的增大，材料去除速率不断增大，随着保持架偏心距的增大，材料去除速率降低。

随着固着磨料粒度的减小，微球的圆度和表面粗糙度降低，材料去除速率降低。

关键词：自转一阶非连续；双平盘研磨；微球；运动学分析；研磨轨迹；研磨参数中图分类号：TG356.28 文献标志码：A 文章编号：1001-3660(2024)08-0133-12DOI：10.16490/ki.issn.1001-3660.2024.08.012Kinematic Analysis and Experimental Study of Microsphere Double-plane Lapping Based on Rotation Function First-order DiscontinuityLYU Xun1,2*, LI Yuanyuan1, OU Yangyang1, JIAO Ronghui1, WANG Jun1, YANG Yuze1(1. College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310023, China;2. Xinchang Research Institute of Zhejiang University of Technology, Zhejiang Shaoxing 312500, China)ABSTRACT: Microspheres are critical components of precision machinery such as miniature bearings and lead screws. Their surface quality, roundness, and batch consistency have a crucial impact on the quality and lifespan of mechanical parts. Due to收稿日期：2023-07-28；修订日期：2023-09-26Received：2023-07-28；Revised：2023-09-26基金项目：国家自然科学基金（51975531）Fund：National Natural Science Foundation of China (51975531)引文格式：吕迅, 李媛媛, 欧阳洋, 等. 基于自转一阶非连续式微球双平盘研磨的运动学分析与实验研究[J]. 表面技术, 2024, 53(8): 133-144.LYU Xun, LI Yuanyuan, OU Yangyang, et al. Kinematic Analysis and Experimental Study of Microsphere Double-plane Lapping Based on Rotation Function First-order Discontinuity[J]. Surface Technology, 2024, 53(8): 133-144.*通信作者（Corresponding author）·134·表面技术 2024年4月their small size and light weight, existing ball processing methods are used to achieve high-precision machining of microspheres. Traditional concentric spherical lapping methods, with three sets of circular ring trajectories, result in poor lapping accuracy. To achieve efficient and high-precision processing of microspheres, the work aims to propose a method based on the first-order discontinuity of rotation for double-plane lapping of microspheres. Firstly, the principle of the first-order discontinuity of rotation for double-plane lapping of microspheres was analyzed, and it was found that the movement of the microsphere changed when it was in different regions of the upper variable friction plate, resulting in a sudden change in the microsphere's rotational axis azimuth and expanding the lapping trajectory. Next, the movement of the microsphere in the first-order discontinuity of rotation for double-plane lapping method was analyzed, and the sliding ratio was introduced to measure the motion state of the microsphere in different friction coefficient regions. It was observed that the sliding ratio of the microsphere varied in different friction coefficient regions. As a result, when the microsphere passed through the transition area between the large and small friction regions of the upper variable friction plate, the sliding ratio changed, causing a sudden change in the microsphere's rotational axis azimuth and expanding the lapping trajectory. The lapping trajectory under different sliding ratios was simulated by MATLAB, and the results showed that with the increase in simulation time, the first-order discontinuity of rotation for double-plane lapping method could achieve full coverage of the microsphere's lapping trajectory, making it more suitable for precision machining of microspheres. Finally, based on the above research, an experimental platform for the first-order discontinuity of rotation for double-plane lapping of microsphere was constructed. With 1 mm diameter bearing steel balls as the processing object, single-factor experiments were conducted to study the effects of lapping pressure, lower plate speed, eccentricity of the holding frame, and grit size of fixed abrasives on microsphere roundness, surface roughness, and material removal rate. The experimental results showed that under the first-order discontinuity of rotation for double-plane lapping, the microsphere's rotational axis azimuth underwent a sudden change, leading to full coverage of the lapping trajectory on the microsphere's surface. Under the lapping pressure of 0.10 N, the lower plate speed of 20 r/min, the eccentricity of the holder of 90 mm, and the grit size of fixed abrasives of 3000 meshes, the roundness of the microsphere decreased from 1.14 μm before lapping to 0.25 μm, and the surface roughness decreased from 0.129 1 μm to 0.029 0 μm. As the lapping pressure and lower plate speed increased, the microsphere roundness and surface roughness were firstly improved and then deteriorated, while the material removal rate continuously increased. As the eccentricity of the holding frame increased, the roundness was firstly improved and then deteriorated, while the material removal rate decreased. As the grit size of fixed abrasives decreased, the microsphere's roundness and surface roughness were improved, and the material removal rate decreased. Through the experiments, the optimal parameter combination considering roundness and surface roughness is obtained: lapping pressure of 0.10 N/ball, lower plate speed of 20 r/min, eccentricity of the holder of 90 mm, and grit size of fixed abrasives of 3000 meshes.KEY WORDS: rotation function first-order discontinuity; double-plane lapping; microsphere; kinematic analysis; lapping trajectory; lapping parameters随着机械产品朝着轻量化、微型化的方向发展，微型电机、仪器仪表等多种工业产品对微型轴承的需求大量增加。

机械敏感性离子通道蛋白Piezo1在椎间盘髓核细胞中的表达及意义1. 引言1.1 Piezo1是什么Piezo1是一种机械敏感性离子通道蛋白，是最新发现的一种参与机械感应的蛋白分子。

它的发现填补了机械感应通路中的一个关键缺口，为人们深入研究细胞对于外部机械刺激做出响应的机制提供了新的线索。

Piezo1作为机械感知通道蛋白，能够感知和传导机械刺激，从而引发细胞内一系列生理反应。

它在多种细胞类型中均有表达，在哺乳动物的细胞中广泛存在。

Piezo1的结构研究表明，其蛋白分子呈现出类似于激活门控离子通道的结构，具有特殊的机械感受性。

Piezo1是一种重要的机械感知通道蛋白，在细胞内扮演着重要的角色。

通过对Piezo1的研究，可以更深入地了解细胞对于机械刺激的感知和响应机制，为相关疾病的治疗提供新的思路和途径。

Piezo1的发现和研究将为生命科学领域的进一步发展带来新的突破和机遇。

1.2 机械敏感性离子通道蛋白在细胞中的作用机械敏感性离子通道蛋白在细胞中起着重要的作用。

细胞内的Piezo1通道是一种重要的机械感受器，可以感知和传导细胞外的机械力信号。

当外部机械力作用在细胞膜上时，Piezo1通道会被激活，导致离子通道开放，进而引发钙离子通道通透性的改变，从而影响细胞内的钙离子浓度。

这一过程是细胞对于机械刺激做出快速反应的重要机制。

Piezo1通道不仅在传递机械信号中起到关键作用，还参与了多种细胞活动，如胞外基质的附着、细胞迁移、细胞增殖、细胞肥大等。

在神经元和心肌细胞中，Piezo1通道还参与到神经递质释放和心律的调节中。

Piezo1通道不仅在椎间盘髓核细胞中具有重要作用，还在许多其他细胞类型中发挥着重要功能。

深入研究Piezo1通道的作用机制，将有助于揭示细胞对于机械刺激的感知和响应机制，同时也有望为相关疾病的治疗提供新的思路和靶点。

2. 正文2.1 椎间盘髓核细胞中Piezo1的表达情况针对椎间盘髓核细胞中Piezo1的表达情况进行了研究。

㊀第40卷㊀第10期2021年10月中国材料进展MATERIALS CHINAVol.40㊀No.10Oct.2021收稿日期:2021-01-25㊀㊀修回日期:2021-02-10基金项目:国家自然科学基金面上项目(11874098);兴辽英才计划资助项目(XLYC1807156);中央高校基本科研业务费专项资金资助项目(DUT20LAB111)第一作者:王孟怡,女,1995年生,硕士研究生通讯作者:邱志勇,男,1978年生,教授,博士生导师,Email:qiuzy@DOI :10.7502/j.issn.1674-3962.202101019导电氧化铋薄膜的逆自旋霍尔效应王孟怡,邱志勇(大连理工大学材料科学与工程学院三束材料改性教育部重点实验室辽宁省能源材料及器件重点实验室,辽宁大连116000)摘㊀要:自旋霍尔效应及其逆效应作为自旋电子学中实现自旋-电荷转换的核心物理效应,对纯自旋流的产生㊁探测有着重要的应用价值,是自旋电子器件开发与应用的关键技术节点㊂对高自旋-电荷转换效率材料体系的探索与开发是该领域的核心课题㊂以导电氧化铋薄膜为对象,研究其中的逆自旋霍尔效应㊂采用交流磁控溅射系统,使用氧化铋陶瓷靶制备了不同厚度的导电氧化铋薄膜,并与坡莫合金薄膜构成铁磁/非磁双层自旋泵浦器件,在该器件中首次观测并确认了导电氧化铋薄膜中逆自旋霍尔效应所对应的电压信号㊂通过逆自旋霍尔电压对氧化铋薄膜厚度的依存关系,定量地估算了氧化铋薄膜的自旋霍尔角及自旋扩散长度㊂通过提出一种新的具备可观测逆自旋霍尔效应的材料体系,不仅拓展了自旋电子材料的选择空间,也为新型自旋电子器件的设计和应用提供了思路㊂关键词:氧化铋;导电氧化物;逆自旋霍尔效应;自旋霍尔角;自旋扩散长度;自旋泵浦中图分类号:O469㊀㊀文献标识码:A㊀㊀文章编号:1674-3962(2021)10-0756-05Inverse Spin Hall Effect of Conductive Bismuth OxideWANG Mengyi,QIU Zhiyong(Key Laboratory of Energy Materials and Devices (Liaoning Province),Key Laboratory of Materials Modificationby Laser,Ion and Electron Beams,Ministry of Education,School of Materials Science and Engineering,Dalian University of Technology,Dalian 116000,China)Abstract :The direct and inverse spin Hall effect is the key effect for spin-charge conversion in spintronics,which plays avital role in the generation and detection of pure spin currents.It is a core issue to develop and explore materials with high spin-charge conversion efficiency.Here,we demonstrate the inverse spin Hall effect in a conductive bismuth oxide.The bis-muth oxide thin films with different thicknesses were prepared from a sintered bismuth oxide target by an rf-sputtering sys-tem.Then,permalloy /bismuth oxide bilayer spin pumping devices were developed,with which voltage signals corresponding to the inverse spin Hall effect were confirmed by the spin pumping technique.Furthermore,by systematical studying of bis-muth-oxide thickness dependence of those spin Hall voltages,the spin Hall angle and spin diffusion length were quantitative-ly estimated.Our results propose a novel system with an observable inverse spin Hall effect,which expands the possibility of spintronic materials and guides a new path for the development of spin-based devices.Key words :bismuth oxide;conductive oxide;inverse spin Hall effect;spin Hall angle;spin diffusion length;spin pumping1㊀前㊀言自旋电子学是以电子的量子自由度自旋为研究核心的新兴科研领域[1]㊂因在电子信息领域中的巨大应用潜力,自旋电子学建立伊始即吸引了众多研究者,现今是凝聚态物理领域不可忽视的科研分支之一㊂凝聚态体系中自旋的产生㊁操纵与检测相关的机理探讨和应用拓展是自旋电子学领域的核心课题[2]㊂本文所讨论的逆自旋霍尔效应即自旋霍尔效应的逆效应,是实现自旋流向电流转换的重要物理效应,其对自旋流特别是纯自旋流的检测有着不可替代的应用价值㊂逆自旋霍尔效应一方面可直接应用于弱自旋流的检测,另一方面也可作为自旋流-电流的转换媒介实现自旋向电荷体系的能量及信息传博看网 . All Rights Reserved.㊀第10期王孟怡等:导电氧化铋薄膜的逆自旋霍尔效应递[3-5]㊂而逆自旋霍尔效应的应用长期受制于自旋流-电流转换效率,即自旋霍尔角[6]㊂因此,新材料体系的探索及高自旋霍尔角材料的开发是逆自旋霍尔效应应用的关键所在㊂由于具有较大的自旋轨道耦合强度,重金属及其合金体系长期以来是高自旋霍尔角材料的研发重点[7-17]㊂其中贵金属Pt和Au的自旋霍尔角在室温附近分别可达11%ʃ8%和11.3%[7,8],是最常用的自旋霍尔材料㊂重金属合金AuW及CuBi报道的自旋霍尔角也达到10%以上[9,10]㊂此外,其它材料如半导体体系也是逆自旋霍尔效应的研究热点㊂2012年,Ando等[18]首次在室温下观测到p型半导体Si中的逆自旋霍尔效应,开拓了半导体中自旋霍尔效应及其逆效应的研究㊂此外,Olejník等[19]在外延的GaAs超薄膜中观测到逆自旋霍尔效应,并估算其自旋霍尔角θSHEʈ0.15%㊂有机聚合物体系中也被发现具有可观测的逆自旋霍尔效应[20,21]㊂Qaid等[20]在导电聚合物PEDOTʒPSS中观测到约2%的自旋霍尔角,进一步拓展了逆自旋霍尔效应的材料空间㊂另一方面,氧化物因其数量庞大的物质群及丰富多变的物理特性,一直以来都是凝聚态物理和材料研究的重点㊂而氧化物具有合成容易㊁性能稳定㊁价格低廉等特点,成为应用型功能材料的优先选项㊂自旋电子学领域的研究者很早就关注并对氧化物中的逆自旋霍尔效应进行了探索㊂在导电氧化物ITO㊁IrO2等材料中先后观测到逆自旋霍尔效应[22-24]㊂其中5d金属氧化物IrO2的自旋霍尔角达到6.5%[24],揭示了重金属氧化物作为自旋功能材料应用的可能,也拓展了氧化物体系中自旋霍尔功能材料的开发方向㊂本工作以导电氧化铋(Bi2O3)薄膜为研究对象,构建并制备了坡莫合金(Py)/Bi2O3的双层自旋泵浦器件㊂并利用自旋泵浦技术对Bi2O3中的逆自旋霍尔效应进行了系统的研究㊂首先在Bi2O3薄膜中观测并确认了逆自旋霍尔效应对应的电压信号;通过对Bi2O3薄膜厚度与信号强度的系统分析,确认该信号与自旋泵浦效应的等效电路模型预测相符;并定量地给出了Bi2O3薄膜的自旋霍尔角和自旋扩散长度㊂2㊀实验原理与方法本工作通过交流磁控溅射由烧结Bi2O3靶材制备了Bi2O3薄膜㊂通过控制成膜时气压(Ar:0.7Pa)及后期真空热处理工艺(<3ˑ10-5Pa,1h@500ħ),在具有热氧化层的硅基板上成功制备了导电Bi2O3薄膜㊂利用四端法确定Bi2O3薄膜的的电导率为2.1ˑ104Ω-1㊃m-1㊂通过改变成膜时间,系统地制备了膜厚范围在12~112nm的Bi2O3薄膜㊂并利用电子束沉积技术将10nm的Py薄膜与Bi2O3膜复合,构建了如图1a所示的Py/Bi2O3双层自旋泵浦器件㊂其中由10nm的Py单层薄膜测得的电导率为1.5ˑ106Ω-1㊃m-1㊂图1b是具有SiO2氧化层的硅基板上沉积的Py/Bi2O3双层膜的X射线衍射图谱,其中Py层与Bi2O3层的厚度分别为10和32nm㊂在2θ=69.1ʎ附近可观测到属于硅基板(400)晶面的强衍射峰;而2θ=27.7ʎ附近可以观测到微弱的特征衍射峰,对比衍射数据库可以判断该衍射峰来源于δ-Bi2O3的(111)晶面;除此之外,无明显可观测的衍射峰,由此判断器件中的Bi2O3为萤石结构的δ-Bi2O3相[25-27],并具备法线方向为[111]的择优取向㊂考虑到测得的薄膜电导率与离子导电的纯δ-Bi2O3的电导率之间存在差异[28],不能排除器件中的Bi2O3薄膜存在氧缺陷或伴生金属铋相从而导致薄膜的电导率上升㊂在衍射图谱中没有明显的氧化硅及Py特征峰,可以归因于氧化硅和Py均为非晶态结构且Py层膜厚过薄㊂图1㊀Py/Bi2O3双层膜器件及自旋泵浦实验设置示意图,H为外加磁场(a);具有SiO2氧化层的硅基板上Py/Bi2O3双层膜的X射线衍射图谱(b)Fig.1㊀Schematic illustration of the Py/Bi2O3bilayer system and spin-pumping set-up,H is the external magnetic field(a);XRD patterns of the Py/Bi2O3bilayer film on an oxidizedsilicon substrate(b)图1a还给出了自旋泵浦实验设置的示意图㊂实验样品置于TE011微波谐振腔中心,微波谐振腔特征频率为9.444GHz,此时样品处微波的电场分量取最小,而磁场分量取最大㊂同时在样品膜面方向上施加外磁场H㊂在微波的交变磁场与外磁场的共同作用下,当微波频率f 与外磁场大小H满足共振条件:757博看网 . All Rights Reserved.中国材料进展第40卷2πf =μ0γH FMR (H FMR +4πM s )(1)Py 中的铁磁共振被激发,其中γ和4πM s 分别是Py 薄膜的有效旋磁比和饱和磁化强度[29]㊂由自旋泵浦模型可知,此时Py 与Bi 2O 3薄膜界面产生自旋积累,纯自旋流J s 将通过界面注入到Bi 2O 3层中[20-22,29-36]㊂由于Bi 2O 3中的逆自旋霍尔效应,该自旋流将被转换为电流,并以电场E ISHE 的形式被检测㊂这里E ISHE :E ISHE ɖJ s ˑσ(2)其中,σ为磁性层的自旋极化矢量,E ISHE ,J s 与σ互为正交矢量时E ISHE 取最大值㊂E ISHE 可以通过Bi 2O 3表面两端的电极测量㊂3㊀结果与讨论图2a 给出了Py /Bi 2O 3双层膜器件中测得的典型铁磁共振微分吸收谱d I (H )/d H ㊂其中I 为微波吸收强度,H 为外磁场强度㊂由共振微分吸收谱可知,在H FMR ʈ99mT时,d I (H )/d H=0,即该磁场强度处微波吸收强度I 达到最大值,为Py 的铁磁共振场㊂图中正负峰值的间距对应图2㊀Py /Bi 2O 3双层膜铁磁共振微分吸收谱d I (H )/d H 和外加磁场H 的依存关系,I 为微波吸收强度(a);Py /Bi 2O 3双层膜中测得的电压信号V 与磁场强度H 的关系图,其微波功率为200mW(图中空心圆为实测数据,红色虚线为Lorentz 及其微分函数的拟合结果,蓝绿虚线分别为拟合曲线中的对称和反对称分量)(b)Fig.2㊀External magnetic field H dependence of the FMR signal d I (H )/d H for the Py /Bi 2O 3bilayer film,I denotes the microwave ab-sorption intensity (a);external magnetic field H dependence of the voltage signal V for the Py /Bi 2O 3bilayer film excited by mi-crowave with a power of 200mW (open circles are the experimen-tal data,the dash curves are the fitting results)(b)铁磁共振线宽W ,对比单层10nm 的Py 薄膜,Py /Bi 2O 3双层膜的铁磁共振线宽W 明显增大,表明在双层膜器件中由于铁磁共振的激发,产生了基于自旋泵浦效应的自旋流[31]㊂该自旋流通过Py /Bi 2O 3界面被注入到Bi 2O 3层㊂如图2b 所示,当固定微波功率为200mW 时,Py /Bi 2O 3双层膜在垂直于外磁场方向上可以测得与铁磁共振相对应的电压信号,其电压峰值对应的磁场基本与铁磁共振场H FMR 相符㊂利用Lorentz 及其微分函数拟合,可以很好地再现电压V 与磁场H 的依存关系(图2b)㊂其中,Lorentz 微分函数的反对称分量通常归因于自旋整流及其他效应的贡献[29,32-34]㊂从拟合参数可知反对称分量在整个电压信号中的占比小于5%㊂而Lorentz 函数的对称分量V s 主要归因于自旋泵浦产生的自旋流所对应的电压,其峰位与铁磁共振场H FMR 完全对应㊂同时考虑到无法排除对称信号中自旋整流效应的贡献,将电压信号中对称分量V s 定义为[28]:V s =V ISHE +V sr ㊂其中V ISHE 为逆自旋霍尔效应对应的电压信号,V sr 对应自旋整流效应的电压信号㊂图3a 和3b 分别给出了在外磁场方向不同的情况下测得的铁磁共振微分吸收谱d I (H )/d H 与电压信号V 对外磁场强度H 与铁磁共振场H FMR 的差值的依存关系图,其中外磁场方向角θH 的定义如图3c 中的插图所示㊂在改变外磁场方向角θH 的情况下,微波微分吸收谱的形状与线宽基本没有发生改变(图3a)㊂而电压信号V 随θH 的变化产生了较大的差异(图3b),当外磁场平行于膜面,即θH =ʃ90ʎ时,电压峰值取最大值,符号相反;当外磁场垂直于膜面,即θH =0ʎ时,电压峰信号消失㊂由式(2)可知,在自旋泵浦实验中逆自旋霍尔效应的信号大小与磁性层中的自旋极化方向相关,即E ISHE ɖsin θM ㊂这里θM 对应铁磁薄膜磁化方向与薄膜法线方向的夹角,可以根据铁磁共振场数据及外磁场方向角θH 计算获得[22,31,35]㊂考虑到薄膜样品中退磁场的影响,当且仅当磁场方向与膜面平行或在法线方向(即θH =ʃ90ʎ,0ʎ)时,铁磁薄膜的磁化方向与外磁场方向相同,此时E ISHE 取正负最大值和零㊂在Py /Bi 2O 3双层膜器件中测得的电压信号很好地符合了该实验模型㊂对所有外磁场方向角θH 下测得的电压数据进行Lorentz 及其微分函数拟合,分离出的电压信号对称分量V s 与外磁场方向角θH 的关系如图3c 所示㊂铁磁层Py 磁化强度M //H eff =H +H M ,这里H 为外加磁场,H M 为Py 薄膜的退磁场㊂V s 的磁场方向角θH 依存可以很好地基于自旋泵浦的动力学模型拟合[22,31,35,36],从而验证了V s中逆自旋霍尔效应的贡献占主导地位㊂857博看网 . All Rights Reserved.㊀第10期王孟怡等:导电氧化铋薄膜的逆自旋霍尔效应图3㊀不同外磁场方向角θH 下Py /Bi 2O 3双层膜的铁磁共振微分吸收谱d I (H )/d H (a)和电压信号V (b)与外磁场强度H 和铁磁共振场H FMR 差值的关系图;电压信号对称分量V s 与外磁场方向角θH 的关系图(实验数据表示为空心菱形,红色实线为拟合结果,插图中定义了外磁场方向角θH )(c)Fig.3㊀H -H FMR dependence of FMR signals d I (H )/d H (a)and voltagesignals V (b)for the Py /Bi 2O 3bilayer film at various out-planemagnetic field angles θH ;the out-plane magnetic field angle θHdependence of V s (the out-plane magnetic field angle θH is deter-mined in the insert)(c)㊀㊀图4a 中给出了在不同微波功率P MW 下的电压信号V 与外磁场H 的依存关系㊂与自旋泵浦模型的预期相符,电压峰值随着P MW 的增加而增大㊂图4b 为电压信号的对称分量V s 与微波功率P MW 的关系㊂由图可见,在微波功率为0~200mW 范围内,V s 与P MW 呈线性关系,与直流自旋泵浦模型的预测一致[22,30,35]㊂图5给出了Py /Bi 2O 3器件中的V s 对Bi 2O 3层厚度d N的依存关系㊂V s 随Bi 2O 3层厚度d N 的增大而减小,这基本可以归因于随Bi 2O 3层厚度d N 增加所导致的器件整体电阻的减小㊂该结果明显区别于Py /Bi 自旋泵浦器件中自旋泵浦信号随Bi层厚度的增加而先增加后减小的结图4㊀不同微波功率P MW 下的Py /Bi 2O 3双层膜的电压信号V 与磁场H 的关系图(a),电压信号对称分量V s 与微波功率P MW 的依存关系图(b)Fig.4㊀External magnetic field H dependence of voltage signals V for thePy /Bi 2O 3bilayer film at various microwave powers P MW (a),the P MW dependence of the voltage signal V s (b)果[37]㊂因此,在这里忽略可能存在的Rashba-Edelstein 效应等界面效应的影响,根据等效电路模型[29,31],同时考虑到Py 层中自旋整流效应的可能贡献,将V s 表示为[29]:V s =V ISHE +V sr=ωθSHE λtanh(d N /2λ)d N σN +d F σF 2e ћ()j 0s +j srd N σN +d F σF(3)其中,d N ㊁d F ㊁σN 和σF 分别表示Bi 2O 3层和Py 层的厚度d 和电导率σ;j 0s 是Py /Bi 2O 3界面处的自旋流密度,可以通过Py 层中铁磁共振线宽W 的变化量计算获得;j sr表示自旋整流效应对应的等效电流㊂利用式(3)对V s 与Bi 2O 3层厚度d N 依存关系的实验数据进行拟合,可以获得Bi 2O 3薄膜中的自旋霍尔角θSHE 及自旋扩散长度λ㊂如图5所示,拟合所得的θSHE 和λ的上限分别为0.7%和6.5nm,而θSHE 和λ的最佳估测值分别为0.5%和3.5nm㊂4㊀结㊀论本工作利用自旋泵浦效应首次在导电Bi 2O 3薄膜中观测并确认了逆自旋霍尔效应㊂在Py /Bi 2O 3双层膜中探测到的电压信号与逆自旋霍尔效应和自旋泵浦效应的模型相符㊂通过系统探讨逆自旋霍尔电压与Bi 2O 3薄膜厚度的关系,定量地给出了导电Bi 2O 3薄膜中的逆自旋霍尔角约为0.5%,自旋扩散长度约为3.5nm㊂导电Bi 2O 3中逆自旋霍尔效应的发现,不仅拓宽了逆自旋霍尔效应957博看网 . All Rights Reserved.中国材料进展第40卷图5㊀Py/Bi2O3双层膜中Bi2O3厚度d N与电压信号对称分量V s的依存关系(实验数据表示为空心圆,实线为式(3)的拟合结果,插图为Py/Bi2O3双层膜系统中考虑了逆自旋霍尔效应和自旋整流效应的等效电路图)Fig.5㊀The experimental and fitting results of Bi2O3thickness d N dependence of V s for the Py/Bi2O3bilayer films(the insert is theequivalent circuit of the Py/Bi2O3bilayer system,in which inversespin Hall effect and spin-rectification effect are both considered)材料的选择范围,也为新型自旋电子器件的设计和应用提供了新的选择㊂参考文献㊀References[1]㊀FLATTE M E.IEEE Transactions on Electron Devices[J],2007,54(5):907-920.[2]㊀TAKAHASHI S,MAEKAWA S.Science Technology Advanced Materi-als[J],2008,9(1):014105.[3]㊀SCHLIEMANN J.International Journal of Modern Physics B[J],2006,20:1015-1036.[4]㊀JUNGWIRTHT,WUNDERLICH J,OLEJNIK K.Nature Materials[J],2012,11(5):382-390.[5]㊀NIIMI Y,OTANI Y.Reports on Progress in Physics[J],2015,78(12):124501.[6]㊀SINOVA J,VALENZUELA S,WUNDERLICH J,et al.Reviews ofModern Physics[J],2015,87(4):1213-1260.[7]㊀SEKI T,HASEGAWA Y,MITANI S,et al.Nature Materials[J],2008,7(2):125-129.[8]㊀ALTHAMMER M,MEYER S,NAKAYAMA H,et al.Physical Re-view B[J],2013,87(22):224401.[9]㊀LACZKOWSKI P,ROJAS-SÁNCHEZ J C,SAVERO-TORRES M,etal.Applied Physics Letters[J],2014,104(14):142403. 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All Rights Reserved.㊀第10期中国材料进展特约编辑王聪特约编辑雷娜特约编辑刘恩克特约撰稿人方梅特约撰稿人魏大海王㊀聪:北京航空航天大学集成电路科学与工程学院教授,博士生导师㊂1995年在中国科学院物理研究所获得博士学位,曾先后在德国㊁法国㊁美国短期工作㊂长期从事反钙钛矿磁性功能材料㊁反铁磁自旋电子学材料,太阳能光热转换涂层㊁辐射致冷薄膜以及太阳能集热器等的研究㊂在Adv Mater,Phys Rev系列等刊物上发表论文近240篇,SCI他引超过3500次,2020年被评为爱思唯尔(Elsevier)中国被高引学者;授权国家发明专利13项,2012年获得教育部高等学校科学研究优秀成果自然科学二等奖;2020年获得中国材料研究学会科学技术二等奖㊂现兼任中国物理学会理事㊁中国晶体学会理事㊁中国物理学会粉末衍射专业委员会副主任㊁中国材料学会环境材料委员会副主任㊁国家能源太阳能热发电技术研发中心技术委员会委员㊁国际衍射数据中心(ICDD)委员㊁中国物理学会相图委员会委员㊁IEEE PES储能技术委员会(中国)储能材料与器件分委会委员㊂Journal of Solar EnergyResearch Updates主编㊂‘北京航空航天大学学报“‘硅酸盐学报“‘中国材料进展“等杂志编委㊂承担国家 863 项目,国家基金委重点项目等20余项,培养博士㊁硕士研究生近50名㊂雷㊀娜:女,1981年生,北京航空航天大学集成电路科学与工程学院副教授,博士生导师㊂主要研究方向为低维磁性材料的自旋调控,围绕电控磁的低功耗自旋存储与自旋逻辑器件方面取得一定成果,发表相关SCI论文30余篇,包括Nat Commun3篇,Phys Rev Lett,Phys RevAppl,Nanoscale各1篇等㊂其中1篇Nat Com-mun文章为ESI高被引论文;Phys Rev Appl上文章被编辑选为推荐文章㊂刘恩克:男,1980年生,中国科学院物理研究所研究员,博士生导师㊂2012年于中国科学院物理研究所获得博士学位,获中科院院长奖学金特别奖㊁中科院百篇优秀博士论文奖㊂2016~2018年作为 洪堡学者 赴德国马普所进行研究访问,合作导师为Claudia Felser和StuartParkin教授㊂主要从事磁性相变材料㊁磁性拓扑材料㊁磁性拓扑电/热输运等研究㊂在国际上首次实现了磁性外尔费米子拓扑物态,提出了全过渡族Heusler合金新家族,发现了 居里温度窗口 效应,提出了等结构合金化 方法等㊂已在Science,NatPhys,Nat Commun,SciAdv,PRL等期刊上发表学术论文200篇㊂曾获国家基金委 优青 基金㊁中科院青促会优秀会员基金㊁国家自然科学二等奖(4/5)等㊂方㊀梅:女,1984年生,中南大学物理与电子学院副教授,硕士生导师㊂长期从事功能薄膜㊁自旋电子器件的设计㊁制备与表征的研究工作,探索自旋电子学相关机理㊂以第一作者/通讯作者在Nature Com-munications(2篇)㊁Physical Review Applied,APL Materials,AppliedPhysics Letters等国际期刊上发表学术论文20余篇,获得国家授权发明专利1项㊂主持国家自然科学基金青年项目㊁湖南省自然基金面上项目㊁中国博士后科学基金一等资助和特别资助㊁中南大学 猎英计划 等项目多项㊂兼任PhysicalReview Letters,PhysicalReview Applied等10余个国际期刊审稿人㊂魏大海:男,1982年生,2009年博士毕业于复旦大学物理系,现任中国科学院半导体研究所研究员,博士生导师㊂2010~2015年先后在日本东京大学物性研究所㊁德国雷根斯堡大学开展博士后研究㊂主要致力于半导体自旋电子学的物理与器件研究,基于新型自旋电子材料开展注入㊁探测以及调控,通过自旋霍尔效应㊁自旋轨道矩等自旋相关输运现象,探索自旋流的各种新奇特性及其可能的应用㊂在Nature Com-munications㊁Phys RevLett,等期刊上发表40余篇论文㊂曾获 国家海外高层次青年人才 ㊁德国洪堡 学者奖金㊁亚洲磁学联盟青年学者奖,作为负责人入选首批中特约撰稿人邱志勇科院稳定支持基础研究领域青年团队 ,承担十三五 国家重点研发计划 量子调控与量子信息 专项青年项目㊂邱志勇:男,1978年生,大连理工大学材料科学与工程学院教授,博士生导师㊂长期从事功能材料与自旋电子学融合领域的研究工作,近年来在Nature Materi-als,Nature Comm,PRL,ACTA Mater等知名杂志上发表论文60余篇,H因子25,引用2200余次㊂依托材料开发背景,在自旋电子材料及自旋物理方向进行了长期研究,近两年以推进新一代磁存储器技术为目标,致力于反铁磁自旋电子学领域的开拓,取得了基于反铁磁材料的自旋物理及应用相关的一系列先驱性成果㊂167博看网 . 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高压球囊扩张左前臂自体动静脉内瘘狭窄的临床研究廖佳隆1胡荣梅2田云飞3（1宁都县人民医院，江西宁都342800）（2宁都县石上中心卫生院，江西宁都342802）（3赣州市人民医院，江西赣州341000）性硬膜下血肿的效果[J].中国老年学杂志，2017，37（24）：6165-6166.[3]吴俊，许文辉，马铁梁，等.神经内镜血肿清除术与软通道引流术对慢性硬膜下血肿的疗效分析[J].临床神经外科杂志，2019，16（6）：492-496.[4]龙武华.两种术式对老年慢性硬膜下血肿患者神经功能及预后的影响比较[J].基层医学论坛，2019，23（28）：4076-4077.[5]陈景南，陈才红，江力，等.神经内镜下小骨窗开颅清除慢性硬膜下血肿的疗效分析[J].浙江医学，2018，40（13）：1492-1494.（收稿日期：2020-09-14）基金项目：赣州市指导性科技计划项目（GZ2018ZSF703）作者简介：廖佳隆，男，本科，主治医师。

【摘要】目的探讨高压球囊扩张左前臂自体动静脉内瘘狭窄的临床效果。

方法选取赣州市人民医院2017年6月—2019年6月收治的30例左前臂自体动静脉内瘘狭窄患者，采用高压球囊进行内瘘狭窄扩张成形术，并对手术平均扩张次数、手术成功率、术后出血率、术后6个月血透通路初级通畅率、术后6个月病死率等进行分析。

结果30例前臂AVF 狭窄患者高压球囊内瘘狭窄扩张成形术均获得成功，手术成功率100%，术后患者原临床症状均消失，可实施正常血液透析至少1次。

球囊的扩张压力介于10~24atm ，平均测验为（15.37±0.83）atm ，平均扩张次数为（1.27±0.89）次，30例患者术后未发生破裂出血及>30%残余狭窄病例，均对扩张效果满意。

给予全部患者6个月以上随访，平均随访期（8.13±2.29）个月，术后6个月内无死亡病例。

术后6个月血透通路的初级通畅率为94.5%。

BioRID Ⅱ假人脊柱动态标定问题研究师玉涛刘洋张世凯杨劲松摘要：BioRID Ⅱ假人用于鞭打试验前需标定，确保其状态符合要求。

由于脊柱结构复杂，多采用橡胶块和塑料，结构相对不稳定，性能易变化；且所评价指标多，运动姿态复杂并隐藏在夹克内部，无法观察不易理解，工程师得不到问题解决正确方向以及所以然。

本文目的是基于假人结构特点，通过标定数据曲线与假人标定运动姿态对应分析，反推每个标定指标的内涵及意义，研究假人调整装置和调整方法的原理，最终利用所得知识及结论去解决标定不能通过的具体问题。

关键词：BioRID Ⅱ；脊柱动态标定；运动姿态；调整装置Research of BioRIDⅡdummy spine dynamic calibrationShi Yutao，Liu Yang，Zhang Shikai，Yang Jinsong（R&D Center of Great Wall Motor Company,Automotive Engineering Technical Center of Hebei Province,Hebei Baoding 071000,China）Abstract：Before the BioRID II dummy is used in the test,it must be calibrated to ensure its state meets the requirements.Because of complexity of spine,rubber blocks and plastics are mostly used,which led to instability in structure and active performance; moreover,there are many evaluation indexes,the motion posture of dummy is complex and hidden in the jacket,so difficult to observe and understand,and the engineer cann’t get the right direction to solve the problem and why it is.The purpose of this paper is to deduce the connotation and significance of eachindex,through the corresponding analysis of the calibration data curve and dummy movement,based on the characteristics of dummy structure,study the principle of dummy adjusting device and method,finally use the knowledge and conclusions to solve the specific problems.Key words: BioRID Ⅱ,spine dynamic calibration,movement attitude,adjusting device 前言BioRID Ⅱ假人是鞭打试验中的核心设备，我国C-NCAP以及Euro NCAP都有对鞭打试验的要求[1]，鞭打试验的目的是检测在低速后面碰撞中，座椅及头枕对驾驶员颈部保护的情况。

Fluid-Structure Interaction and Dynamics Fluid-structure interaction (FSI) and dynamics is a complex and fascinating field that involves the study of the interaction between a fluid and a solid structure. This interaction can occur in a wide range of natural and engineered systems, from the flow of blood through arteries to the behavior of aircraft wings in flight. Understanding and predicting the behavior of these systems is crucialfor a wide range of applications, from designing more efficient and stable structures to improving the performance of medical devices. One of the key challenges in FSI and dynamics is the need to develop accurate and efficient numerical methods for simulating the behavior of these systems. This requires a deep understanding of both fluid mechanics and structural mechanics, as well asthe ability to develop and implement complex algorithms that can accuratelycapture the interactions between the fluid and the structure. Researchers in this field are constantly pushing the boundaries of computational methods, seeking to develop new techniques that can provide more accurate and reliable predictions of FSI behavior. In addition to the computational challenges, FSI and dynamics also present significant experimental and theoretical challenges. Experimental studies of FSI behavior often require the development of specialized test rigs and measurement techniques, as well as the ability to interpret complex and often non-linear data. Theoretical studies, on the other hand, require the development of new mathematical models and analytical techniques that can accurately capture the behavior of FSI systems. Both experimental and theoretical studies in this field require a deep understanding of the underlying physics and a creative approach to problem-solving. From a practical perspective, FSI and dynamics have a wide range of applications in engineering and science. For example, in the field of aerospace engineering, understanding the behavior of FSI systems is crucial for designing more efficient and stable aircraft and spacecraft. In the field of civil engineering, FSI studies are important for designing more resilient and durable structures, such as bridges and offshore platforms. In the field of biomedical engineering, FSI studies are crucial for developing more effective medical devices, such as artificial heart valves and drug delivery systems. The study of FSI and dynamics also has important implications for our understanding of the naturalworld. For example, understanding the behavior of FSI systems is crucial for understanding the behavior of natural systems such as the flow of blood through arteries and the behavior of marine organisms in water. By studying FSI and dynamics, researchers can gain new insights into the fundamental principles that govern the behavior of these systems, leading to new discoveries and innovations in a wide range of fields. In conclusion, the study of fluid-structureinteraction and dynamics is a complex and multifaceted field that presents a wide range of challenges and opportunities. From the development of new computational methods to the practical applications in engineering and science, FSI and dynamics play a crucial role in advancing our understanding of the natural world and developing new technologies that can improve our lives. As researchers continue to push the boundaries of this field, we can expect to see new discoveries and innovations that will have a profound impact on a wide range of fields.。

a r X i v :c o n d -m a t /0302357v 1 [c o n d -m a t .m e s -h a l l ] 18 F eb 2003Flow equation renormalization of a spin-boson model with astructured bathSilvia Kleffa ,1,Stefan Kehrein b ,Jan von Delft aa Lehrstuhl f¨u r Theoretische Festk¨o rperphysik,Ludwig-Maximilians Universit¨a t,Theresienstr.37,80333M¨u nchen,Germany bTheoretische Physik III –Elektronische Korrelationen und Magnetismus,Universit¨a t Augsburg,86135Augsburg,Germany1.Introduction -ModelRecently a new strategy for performing measure-ments on solid state (Josephson)qubits was proposed which uses the entanglement of the qubit with states of a damped oscillator [1],with this oscillator repre-senting the plasma resonance of the Josephson junc-tion.This system of a spin coupled to a damped har-monic oscillator (see Fig.1)can be mapped to a stan-dard model for dissipative quantum systems,namely the spin-boson model [2].Here the spectral function governing the dynamics of the spin has a resonance peak.Such structured baths were also discussed in con-nection with electron transfer processes [2].We use the flow equation method introduced by Wegner [3]to an-alyze the system shown in Fig.1,consisting of a two-2σx +ΩB †B +g (B †+B )σz +k˜ωk ˜b †k ˜b k+(B †+B )kκk (˜b †k +˜b k )+(B †+B )2 kκ2k2σx +1(Ω2−ω2)2+(2πΓωΩ)2with α=8Γg 2infinitesimal unitary transformations.The continuous sequence of unitary transformations U (l )is labelled by a flow parameter l .Applying such a transformation to a given Hamiltonian,this Hamiltonian becomes a function of l :H (l )=U (l )H U †(l ).Here H (l =0)=H is the initial Hamiltonian and H (l =∞)is the final diagonal ually it is more convenient to work with a differential formulation d H (l )dlU −1(l ).(3)Using the flow equation approach one can decouple system and bath by diagonalizing H (l =0)[4]:H (l =∞)=−∆∞2∆−ωk2q ,kλk λq I (ωk ,ωq ,l )(b k +b †k )(b q −b †q ),(5)with I (ωk ,ωq ,l )=ωqωk +∆+ωq −∆∂l=−2(ω−∆)2J (ω,l )(6)+2∆J (ω,l )d ω′J (ω′,l )I (ω,ω′,l ),d ∆ω+∆.(7)The unitary flow diagonalizing the Hamiltonian gener-ates a flow for σz (l )which takes the structure σz (l )=h (l )σz +σxkχk (l )(b k +b †k ),(8)where h (l )and χk (l )obey the differential equations dhωk +∆,(9)dχkωk +∆+qχq λk λq ∆I (ωk ,ωq ,l ).(10)One can show that the function h (l )decays to zero asl →∞.Therefore the observable σz decays completely into bath operators [4].J (ω)/Ωω/∆0C (ω)∆0Fig.2.(a)Different effective spectral functions J (ω,l =0)and(b)the corresponding C (ω)for ΩΓ=0.06and α=0.15.The inset shows the term scheme of a two-level system coupled to a harmonic oscillator for the two limits ∆0≪Ωand ∆0≫Ω.We integrated the flow equations numerically in or-der to calculate the Fourier transform,C (ω),of the spin-spin correlation function C (t )≡1[3]F.Wegner,Ann.Phys.3,77(1994).[4]S.Kehrein and A.Mielke,Ann.Phys.6,90(1997).3。

21 2.The Navier–Stokes and Euler Equations–Fluid and Gas DynamicsFluid and gas dynamics have a decisive impact on our daily lives.There are thefine droplets of water which sprinkle down in our morning shower,the waveswhich we face swimming or surfing in the ocean,the river which adapts to thetopography by forming a waterfall,the turbulent air currents which often disturbour transatlanticflight in a jet plane,the tsunami1which can wreck an entireregion of our world,the athmosphericflows creating tornados2and hurricanes3,the live-givingflow of blood in our arteries and veins4…All theseflows havea great complexity from the geometrical,(bio)physical and(bio)mechanicalviewpoints and their mathematical modeling is a highly challenging task.Clearly,the dynamics offluids and gases is governed by the interactionof their atoms/molecules,which theoretically can be modeled microscopically,i.e.by individual particle dynamics,relying on a grand Hamiltonian functiondepending on3N space coordinates and3N momentum coordinates,where Nis the number of particles in thefluid/gas.Note that the Newtonian ensembletrajectories live in6N dimensional phase space!For most practical purposes thisis prohibitive and it is essential to carry out the thermodynamic Boltzmann–Grad limit,which–under certain hypothesis on the particle interactions–givesthe Boltzmann equation of gas dynamics(see Chapter1on kinetic equations)for the evolution of the effective mass density function in6-dimensional phasespace.Under the assumption of a small particle mean free path(i.e.in the colli-sion dominated regime)a further approximation is possible,leading to time-dependent macroscopic equations in position space R3,referred to as Navier–Stokes and Euler systems.These systems of nonlinear partial differential equa-tions are absolutely central in the modeling offluid and gasflows.For more(precise)information on this modeling hierarchy we refer to[3].The Navier–Stokes system5was written down in the19th century.It is namedafter the French engineer and physicist Claude–Luis Navier6and the Irish math-ematician and physicist George Gabriel Stokes7.1/2/faq/tornado/3/4http://iacs.epfl.ch/cmcs/NewResearch/vascular.php35http://www.navier–/6/∼history/Mathematicians/Navier.html7/∼history/Mathematicians/Stokes.html2The Navier–Stokes and Euler Equations–Fluid and Gas Dynamics 22Fig.2.1.Iguassu Falls,Border of Brazil-Argentina2The Navier–Stokes and Euler Equations–Fluid and Gas Dynamics232The Navier–Stokes and Euler Equations–Fluid and Gas Dynamics 24Fig.2.2.Iguassu Falls,Border of Brazil-Argentina2The Navier–Stokes and Euler Equations–Fluid and Gas Dynamics252The Navier–Stokes and Euler Equations–Fluid and Gas Dynamics26Under the assumption of incompressibility of thefluid the Navier–Stokes equations,determining thefluid velocity u and thefluid pressure p,read:∂u∂t+(u·grad)u+grad p=νΔu+fdiv u=0Here x denotes the space variable in R2or R3depending on whether2or3dimensionalflows are to be modeled and t>0is the time variable.The velocityfield u=u(x,t)(vectorfield on R2or,resp.,R3)is in R2or R3,resp.,and thepressure p=p(x,t)is a scalar function.f=f(x,t)is the(given)external forcefield(again two and,resp.three-dimensional)acting on thefluid andν>0the kinematic viscosity parameter.The functions u and p are the solutions ofthe PDE system,thefluid density is assumed to be constant(say,1)here asconsistent with the incompressibility assumption.The nonlinear Navier–Stokessystem has to be supplemented by an initial condition for the velocityfield andby boundary conditions if spatially confinedfluidflows are considered(or bydecay conditions on whole space).A typical boundary condition is the so-calledno-slip condition which readsu=0on the boundary of thefluid domain.The constraint div u=0enforces the incompressibility of thefluid and serves to determine the pressure p from the evolution equation for thefluid velocity u.Ifν=0then the so called incompressible Euler8equations,valid for very small viscosityflows(idealfluids),are obtained.Note that the viscous Navier–Stokes equations form a parabolic system while the Euler equations(inviscidcase)are hyperbolic.The Navier–Stokes and Euler equations are based on New-ton’s celebrated second law:force equals mass times acceleration.They areconsistent with the basic physical requirements of mass,momentum and energyconservation.The incompressible Navier–Stokes and Euler equations allow an interesting simple interpretation,when they are written in terms of thefluid vorticity,defined byω:=curl u.Clearly,the advantage of applying the curl operator to the velocity equation is the elimination of the pressure.In the two-dimensional case(when vorticitycan be regarded as a scalar since it points into the x3direction when u3is zero)we obtainDω=νΔω+curl f,Dt8/∼history/Mathematicians/Euler.html2The Navier–Stokes and Euler Equations–Fluid and Gas Dynamics27 denotes the material derivative of the scalar function g:where DgDtDg=g t+u.grad g.DtThus,for two-dimensionalflows,the vorticity gets convected by the velocityfield,is diffused with diffusion coefficientνand externally produced/destroyedby the curl of the external force.For three dimensionalflows an additionalterm appears in the vorticity formulation of the Navier–Stokes equations,whichcorresponds to vorticity distortion.The Navier–Stokes and Euler equations had tremendous impact on appliedmathematics in the20th century,e.g.they have given rise to Prandtl’s9boundarylayer theory which is at the origin of modern singular perturbation theory.Nevertheless the analytical understanding of the Navier–Stokes equations is stillsomewhat limited:In three space dimensions,with smooth,decaying(in the farfield)initial datum and forcefield,a global-in-time weak solution is known toexist(Leray solution10),however it is not known whether this weak solution isunique and the existence/uniqueness of global-in-time smooth solutions is alsounknown for three-dimensionalflows with arbitrarily large smooth initial dataand forcingfields,decaying in the farfield.In fact,this is precisely the contentof a Clay Institute Millennium Problem11with an award of USD1000000!!A very deep theorem(see[2])proves that possible singularity sets of weaksolutions of the three-dimensional Navier–Stokes equations are‘small’(e.g.they cannot contain a space-time curve)but it has not been shown that they areempty…We remark that the theory of two dimensional incompressibleflows is muchsimpler,in fact smooth global2−d solutions exist for arbitrarily large smoothdata in the viscid and inviscid case(see[6]).Why is it so important to know whether time-global smooth solutions of theincompressible Navier–Stokes system exist for all smooth data?If smoothnessbreaks down infinite time then–close to break-down time–the velocityfield uof thefluid becomes unbounded.Obviously,we conceiveflows of viscous realfluids as smooth with a locallyfinite velocityfield,so breakdown of smoothnessinfinite time would be highly counterintuitive.Here our natural conception ofthe world surrounding us is at stake!The theory of mathematical hydrology is a direct important consequenceof the Navier–Stokes or,resp.,Euler equations.Theflow of rivers in general–and in particular in waterfalls like the famous ones of the Rio Iguassu on theArgentinian-Brazilian border,of the Oranje river in the South African Augra-bies National Park and others shown in the Figs.2.1–2.6,are often modeledby the so called Saint–V enant system,named after the French civil engineer9http://www.fl/msc/prandtl.htm10/∼history/Mathematicians/Leray.html11/millennium/Navier–Stokes_Equations/2The Navier–Stokes and Euler Equations–Fluid and Gas Dynamics 28Fig.2.3.Iguassu Falls,Border of Brazil-Argentina2The Navier–Stokes and Euler Equations–Fluid and Gas Dynamics292The Navier–Stokes and Euler Equations–Fluid and Gas Dynamics 30Fig.2.4.Augrabies Falls,South AfricaAdh ´e mar Jean Claude Barr ´e de Saint–V enant 12.The main issue is to incor-porate the free boundary representing the height-over-bottom h =h (x ,t )of the water (measured vertically from the bottom of the river).Let Z =Z (x )be the height of the bottom of the river measured vertically from a con-stant 0-level below the bottom (thus describing the river bottom topogra-phy),which in the most simple setting is assumed to have a small variation.Note that here the space variable x in R 1or R 2denotes the horizontal di-rection(s)und u =u (x ,t )the horizontal velocity component(s),the vertical velocity component is assumed to vanish.The dependence on the vertical co-ordinate enters only through the free boundary h .Then,under certain assump-tions,most notably incompressibility,vanishing viscosity,small variation of the river bottom topography and small water height h ,the Saint–V enant system reads:∂h ∂t +div (hu )=0∂(hu )∂t +div (h u ⊗u )+grad g 2h 2 +gh grad Z =0Here g denotes the gravity constant.Note that h +Z is the local level of the water surface,measured vertically again from the constant 0-level below the bottom of the river.For analytical and numerical work on (even more general)Saint–V enant systems we refer to the paper [4].Spectacular simulations of the breaking of a dam and of river flooding using Saint–V enant systems can be found in Benoit Perthame’s webpage 13.Many gas flows cannot generically be considered to be incompressible,par-ticularly at sufficiently large velocities.Then the incompressibility constraint div u =0on the velocity field has to be dropped and the compressible Euler or Navier–Stokes systems,depending on whether the viscosity is small or not,have to be used to model the flow.Here we state these systems under the simplifying assumption of an isentropic flow,i.e.the pressure p is a given function of the (nonconstant!)gas density:p =p (ρ),where p is,say,an increasing differentiable function of ρ.Under this constitutive assumption the compressible Navier–Stokes equations read:ρt +div (ρu )=0(ρu )t +div (ρu ⊗u )+grad p (ρ)=νΔu +(λ+ν)grad(div u )+ρf .Here λis the so called shear viscosity and ν+λis non-negative.For a comprehensive review of modern results on the compressible Navier–Stokes equations we refer to the text [5].For the compressible Euler equations,obtained by setting λ=0and ν=0,globally smooth solutions do not exist in general.Consider the one-dimensional 12/∼history/Mathematicians/Saint–Venant.html 13http://www.dma.ens.fr/users/perthame/case,the so called p -system,without external force:ρt +(ρu )x =0(ρu )t + ρu 2+p (ρ) x =0This is a nonlinear hyperbolic system,degenerate at the vacuum state ρ=0.For an extensive study of the Riemann problem we refer to [7]and for the pioneering proof of global weak solutions,using entropy waves and compensated compactness,to [8].Finally,we remark that the incompressible inviscid Saint–V enant system of hydrology has the mathematical structure of an isotropic compressible Euler system with quadratic pressure law in 1or,resp.,2dimensions,where the spatial ground fluctuations play the role of an external force field.Comments on the Figs.2.1–2.4An important assumption in the derivation of the Saint–V enant system from the Euler or,resp.,Navier–Stokes equations –apart from the shallow water condition –is a smallness assumption on the variation of the bottom topography,i.e.grad Z has to be small.Clearly,this restricts the applicability of the model,in particular its use for waterfall modelling.Recently,an extension of the Saint–V enant system was presented in [1],which eliminates all assumptions on the bottom topography.There the curvature of the river bottom is taken into account explicitely in the derivation from the hydrostatic Euler system (assuming a small fluid velocity in orthogonal direction to the fluid bottom).We remark that extensions of the Saint–V enant models to granular flows (like debris avalanches)exist in the literature,see also [1].Comments on the Figs.2.5–2.6Turbulent flows 14are charcacterized by seem-ingly chaotic,random changes of velocities,with vortices appearing on a variety of scales,occurring at sufficiently large Reynolds number 15.Non-turbulent flows are called laminar,represented by streamline flow,where different layers of the fluid are not disturbed by scale interaction.Simulations of turbulent flows are highly complicated and expensive since small and large scales in the solutions of the Navier–Stokes equations have to be resolved contemporarily.Various simpli-fying attempts (‘turbulence modeling’)exist,typically based on time-averaging the Navier–Stokes equations and using (more or less)empirical closure con-ditions for the correlations of velocity fluctuations.The flows depicted in the Figs.2.5and 2.6are highly turbulent,with apparent micro-scales.We remark that the turbulent parts of the flows depicted in the Figs.2.1–2.6are two-phase flows,due to the air bubbles entrained close to the free water-air surface interacting with the turbulent water flow.Fig.2.5.Turbulent Flow,Cascada de Agua Azul,Chiapas,Mexico14/wiki/Turbulence 15/formulae/fluids/calc_reynolds.cfmregionReferences[1]F.Bouchut,A.Mangeney-Castelnau,B.Perthame and J.-P.Vilotte,A newmodel of Saint Venant and Savage–Hutter type for gravity driven shallow waterflows,C.R.Acad.Sci.Paris,Ser.I336,pp.531–536,2003[2]L.Caffarelli,R.Kohn,and L.Nirenberg,Partial regularity of suitable weaksolutions of the Navier–Stokes equations,Comm.Pure&Appl.Math.35,pp.771–831,1982[3]C.Cercignani,The Boltzmann equation and its Application,Springer-V erlag,1988[4]J.-F.Gerbeau and B.Pertame,Derivation of viscous Saint–Venant system forlaminar shallow water;numerical validation.INRIA RR-4084[5]P-L.Lions,Mathematical Topics in Fluid Dynamics,Vol.2,CompressibleModels,Oxford Science Publication,1998[6]dyzhenskaya,The Mathematical Theory of Viscous Incompressible Flows(2nd edition),Gordon and Breach,1969[7]J.Smoller,Shock Waves and Reaction-Diffusion Equations,(second edition),Springer-V erlag,V ol.258,Grundlehren Series,1994[8]R.DiPerna,Convergence of the Viscosity Method for Isentropic Gas Dynamics,Comm.Math.Phys.,V ol.91,Nr.1,1983。

第45卷第5期包装工程2024年3月PACKAGING ENGINEERING·309·发泡聚乙烯最大加速度-静应力曲线快速获取方法研究宋卫生，薛阳（河南牧业经济学院，郑州450046）摘要：目的研究快速、准确预测最大加速度-静应力曲线的方法。

方法首先利用落锤冲击试验机获取了5个不同高度下，5种不同厚度的发泡聚乙烯的最大加速度-静应力曲线。

在此基础上，分析对比文中3种不同的改进拟合法与已有的动应力与动能量多项式拟合法的区别。

结果研究发现，当不区分高度的情况下，以最大加速度因子为函数值，以跌落高度、衬垫厚度、静应力为变量进行拟合时，其代表预测精度R2的平均为0.835，相比动应力与动能量多项式拟合法的0.299 6要高。

但曲线右侧的预测精度偏低。

引入以静应力为变量的多项式作为修正因子后，R2的平均值为0.934。

预测精度有所提高，右侧的预测偏差减小，但仍存在。

在区分高度的情况下，以带有修正因子的公式进行预测时，R2的平均值为0.984，曲线向右侧预测偏差逐渐增大的现象明显改善。

结论区分高度情况下，利用带修正因子的预测公式可以快速且较准确地预测最大加速度-静应力曲线，可以为冲击防护设计及相关软件的开发提供一定的帮助。

关键词：最大加速度-静应力曲线；应力能量法；预测精度；发泡聚乙烯；多项式拟合中图分类号：TB485.1 文献标志码：A 文章编号：1001-3563(2024)05-0309-06DOI：10.19554/ki.1001-3563.2024.05.037Rapid Acquisition Method of Maximum Acceleration-Static Stress Curve forFoamed PolyethyleneSONG Weisheng, XUE Yang(Henan University of Animal Husbandry and Economy, Zhengzhou 450046, China)ABSTRACT: The work aims to study a method that can predict the maximum acceleration-static stress curve quickly and accurately. Firstly, the maximum acceleration-static stress curves of foamed polyethylene of 5 different thickness at 5 different heights were obtained by a drop hammer impact testing machine. On this basis, the differences between the three different improved fitting methods proposed and the existing dynamic stress and dynamic energy polynomial fitting methods were analyzed and compared. It was found that when the maximum acceleration factor was used as a function value and the drop height, pad thickness, and static stress were used as variables for fitting without distinguishing heights, the average R2 value representing prediction accuracy was 0.835, which was much higher than the value of 0.299 6 got by the polynomial fitting method of dynamic stress and dynamic energy. However, the prediction accuracy on the right side of the curve was still low. After a polynomial with static stress as the variable was used as the correction factor, the average value of R2 was 0.934, indicating a significant improvement in prediction accuracy. The prediction deviation on the right side was reduced, but it still existed. When a formula with a correction factor was used for prediction while heights were distinguished, the average value of R2was 0.984, and the phenomenon of gradually increasing prediction deviation towards the right side of the curve was significantly improved. Under different heights, the use of prediction formulas with correction factors can quickly and accurately predict the maximum acceleration-static stress curve, which收稿日期：2023-11-08基金项目：河南省科技攻关项目（222102210267）；河南省高校重点科研项目（24B140004）·310·包装工程2024年3月can provide certain assistance for impact protection design and related software development.KEY WORDS: maximum acceleration-static stress curve; stress energy method; prediction accuracy; foamed polyethylene;polynomial fitting缓冲包装设计国家标准中[1]，冲击防护设计方法有缓冲系数-最大应力曲线法和最大加速度静应力曲线法。

Evidence-based dosage parameters using electrostimulation as an analgesic;the need for a new approach剂量参数为依据的电刺激疗法——止痛新途径Dr. C. Lucas, PhD, MSc, RPT卢卡斯博士，理学硕士，哲学博士，康复理疗师Department of Clinical Epidemiology & Biostatistics Academic Medical Center, University of Amsterdam, The Netherlands 荷兰阿姆斯特丹大学医学中心——临床流行病学及生物统计学院Faculty of Medical Sciences, Academic Medical Center University of Amsterdam, The Netherlands荷兰阿姆斯特丹大学医学中心教学楼TENS and EBMTENS 和循证医学TENS; the state of the artTENS技术发展水平TENS as a low frequency electrotherapeutic modality exists since 1965, in fields other than physical medicine and rehabilitation as well.This includes neurophysiology assessment and treatment modalities in various other medical disciplines.TENS作为一种低频电疗法，起源于1965年，不仅应用于物理医学及康复领域，也应用于其它各种医学科室中神经生理功能的评估及治疗。

Conventional electrostimulation;a general matter of concern常规电刺激疗法一般观点In comparison to TENS the effectiveness of low and mid-frequency urrents for the treatment of pain has not been sufficiently studied in randomized clinical trials.Therefore, these modalities of electrotherapy will eventually be less frequently used与TENS相似可以治疗疼痛的低中频电疗法，由于没有经过充分的随机对照临床实验研究，因此这些方法在临床上应用的相对较少A specific matter of concern特殊观点•Clinicians using TENS (and IFC) notice unsuccessful treatment effects in almost half of all patients involved•Moreover, also the success rate reported in literature searches is about 50%•临床医生在应用TENS或干扰电时发现有一半的患者没能达到预期的治疗效果•此外，文献研究报道其有效率也大约为50％Why EBM ?选择循证医学的原因•Our daily need for valid information about diagnosis, therapy and prevention.•日常工作中我们需要有效的信息用于诊断、治疗和预防•The inadequacy of traditional sources for this information because they are out of date (textbooks), frequently wrong (experts), ineffective (didactic continuing medical education), or too overwhelming in their volume and too variable in their validity for practical clinical use (medical journals).•信息的传统来源由于多种原因而不足：如教科书落伍、频繁出错的专家个人意见、无效的继续医学教育模式、数量庞大变化万千的医学期刊•The disparity between diagnostic skills and clinical judgement, which increase with experience, and our up-to-date knowledge and clinical performance, which decline.•诊断技能与临床判断间的不同在于，前者随着经验、不断更新的知识和临床应用而增强，后者确下降。