I. Fundamentals of Mechanical Properties of Materials
Four types of mechanical properties of thin films are of interest. The first type is the elastic constants, in which the typical property is Young’s modulus. The other three types are strengths including yield strength, σy , ultimate tensile strength, σu , fracture strength, σf , ductility, i.e., elongation, δ, and reduction of area, ψ or RA, and toughness, i.e., fracture toughness, K IC or G C , and impact energy, which correspond to stress, strain and energy, respectively.
1. Stress-strain Curve
Two definitions of stresses and strains are widely used in academia and industry, namely, engineering (or nominal) stresses and engineering (or nominal) strains, and true stresses and true strains. The basic test to characterize mechanical properties of materials is the tensile test. Figure 2-1 shows a general stress-strain curve obtained from a uniaxial tensile test. In the first stage, stress increases linearly with strain with the slope of Young’s modulus. For brittle-ductile materials, if the stress-strain curve is smooth, yield strength (σy ) is determined by an engineering standard and it is the stress under an offset strain, which is usually taken as 0.2 %. Thus, the yield strength is marked as σ0.2. The ultimate tensile strength represents the ability of a sample to resist uniform deformation under tension, which is calculated from the maximum load (P max ) and the original cross section area (A 0), i.e., σu =P max /A 0. The ultimate tensile strength is the critical point, at which necking occurs and uniform deformation is ended in the tested sample.
Referring to Fig. 1, the conventional tensile test gives the following mechanical properties defined as follows:
Ultimate tensile strength: σu = P max /A 0, (1) Yield strength: σy = P y /A 0, (2) Elongation: δ = (L f -L 0)/L 0, (3) Reduction of area: RA = ψ = (A 0 -A f )/A 0, (4)
where A 0 and L 0 are respectively the original cross sectional area and gauge length, A f and L f are respectively the final cross sectional area and gauge length at fracture, and δ and ψ are the parameters to evaluate ductility. Since the cross sectional area (A) and the gauge length (L) change during tensile testing, true stress (σ) and true strain (ε) are defined as:
σ = P/A (5)
)/ln(/00
L L L dL L
L ==∫ε.
(6)
Nominal (engineering) stress and nominal (engineering) strain are defined as:
σ’=P/A 0, (7) ε’=ΔL/L 0=(L-L 0)/L 0=(L/L 0)-1. (8)
Combining Eqs. (6) and (8) yields
ε=ln(1+ ε’). (9)
It is a widely accepted assumption that during plastic deformation, the sample volume is conserved:
V=A 0L 0=AL =
constant. (10)
If plastic deformation is much more severe than elastic deformation, elastic strain can be ignored. Then, combining Eqs. (10) and (6) leads to
ε= ln(L/L 0)=ln(A 0/A).
(11)
From Eqs. (5) and (7), we have:
σ=(P/A 0)(A 0/A)=σ’ (A 0/A).
(12)
Substituting Eq. (9) into Eq. (10) gives
σ=σ’(1 + ε’). (13)
During a tensile test, necking (local narrowing of the cross section) starts at the maximum load (P max ). At the maximum load, we have:
dP = σdA + Ad σ =
0. (14)
The constant volume approximation gives
dL/L = -dA/A. (15)
Combining Eqs. (15) and (14) leads to: dL/L = d σ/σ = d ε. (16)
Equation (16) is the important condition for necking.
The true stress-true strain (σ - ε) curve for plastic deformation is usually expressed as:
σ = k εn ,
(17)
where k is a constant, which equals the true stress at a unity strain, and n is called strain hardening exponent, the slope of a log(σ)-log(ε) plot. It can be proved that n is numerically equal to the limit of uniform plastic strain. Substituting (17) into (16) results in d σ/d ε = nk εn-1
=σ =k εn . So
n=ε, (18)
i.e., when the true strain is equal to the strain hardening exponent, the necking starts.
The true strain at fracture is calculated from Eq. (9) as follows:
εf = ln(L f /L 0) = ln(A 0/A f ).
(19)
Combining Eq. (19) with Eq. (4), we obtain the relationship between ψ and εf ,
???
?
?????=ψε11ln f .
(20)
It should be emphasized that σu corresponds to the maximum load at which necking starts. After necking, the cross section of the specimen reduces, so the fracture load (P f ) is smaller than the maximum load (P max ). However, the fracture strength σf in true stress-strain curve could be greater than σu . The strains corresponding to P max and P f are called the maximum uniform elongation (εu ) and total elongation (εt ) respectively. Thus:
εt = εu + εnu , (21)
where εnu is the maximum non-uniform elongation after necking.
2. Theoretical Strength
2-1. Fracture Strength
When a piece of solid is under stress, its atoms are displaced from their equilibrium positions. The displacement is governed by the interactomic potential. An applied tensile force against the internal force tends to lengthen the solid and thus to increase the interatomic distance. At equilibrium, an applied force has the same magnitude as the internal force but with an opposite sign. Figure 2(a) shows the applied force versus the interatomic distance, where max F is the maximum force which corresponds to the dissociative distance D r . max F is the maximum tensile force needed to pull the solid apart, because the force needed to increase the interatomic distance beyond D r is less than max F . We can regard max F as the theoretical fracture strength of the solid, which can be estimated from the interatomic potential of a solid.
In simple cases, interatomic potential energy can be, in general, represented by
???
???????????????????=q p b r a q r a p q p pq
r 0011)(εφ, (22)
where p and q are numbers whose values depend on the shape of the potential. The first term in the right side of Eq. (22) represents the repulsive interaction, which is due to the Pauli exclusion principle, and the repulsive interaction occurs only within a very short distance. The second term is the attractive interaction, which binds atoms together. At the equilibrium position, 0a r =, the attraction is balanced by the repulsion, the potential is at its minimum, b a εφ?=)(0, and the force F=0.
For short-range interactions, such as solid Ar, a frozen inert gas, the Lennard-Jones potential (p=12 and q=6) applies, which takes the form:
????
?????????????????=601202)(r a r a r b εφ. (23)
The Lennard-Jones (LJ) potential is also often given by 1
???
?
?????????????????=6124)(r r r b σσεφ (24)
with σσ12.126/10==a . For a frozen inert gas crystal, the total potential energy can be calculated by summing up the LJ potential
???
??????????????????????=∑≠6
12,)4(21
ij ij N i j i b total r r N U σσε. (25)
For simplicity, we consider the nearest-neighbor interaction only. The force between two nearest-neighbors is calculated from Eq. (23)
???
?
??????????+????????=???=7
013001212r a r a a r F b εφ. (26)
The force increases first with stretching, reaches a maximum and then decreases. Near the equilibrium, we have r a r Δ+=0, 0130/131)/(a r r a Δ?≈ and 070/71)/(a r r a Δ?≈, and Eq. (26) is approximately
???
?????????????Δ?=???=00612a r a r F b εφ
. (27)
Equation (27) represent the material recover force. To stretch the material, a force with the
same amplitude but opposite sign must be applied. If the number of bonds per unit area is nN/A, the surface energy can be estimated by using the nearest-neighbor interaction, which will be studied in Chapter II, and is given by
A
nN
N n E A
nN
A c b b ?=
?=
2εγ. (28)
Under small deformation, Hooke’s law gives
00013
00700061212a r
Y a r a A nN r a a r a a a A nN r A nN b b ΔΔεΔΔεφσ=??≈???
?????????????+?????????+?=???=, (29a)
where
1
C. Kittel, Introduction to solid state physics, eighth edition, John Wiley & Sons, Inc, 2005,
72a A nN Y b ε?≡
(29b)
may be called the Young modulus of the ideal solid.
The theoretical fracture strength of a solid is defined as the maximum of the interatomic attraction force, max F , which requires 0=??r F , i.e.,
0713126
0802022=???
?????????
?????????=??r a r a a r b εφ. (30)
Equation (30) yields the dissociative distance D r ,
011.1a r D =. (31)
Theoretically the solid can be elastically stretched (strained) by about 11% to reach its theoretical fracture strength. As mentioned about, a bulk material will deform plastically after the engineering strain beyond 0.2%. However, a thin film can sustain very high strain without plastic deformation. The theoretical fracture strength is then estimated to be
Y a A nN r A nN b r r f D 037.011.1111.111213
70≈?
?????????????????????=???==εφσ. (32)
Eqs. (28), (29b) and (32) indicate the relationships among surface energy, Young’s modulus, and theoretical fracture strength of a crystal, which obeys the Lennard-Jones potential and possesses the nearest-neighbor interaction only.
We may assume that the cohesive force curve can be represented by a sine curve, as shown in Fig. 2(b),
λ
πσσx
2sin max =, (33)
where max σ is the theoretical cohesive strength. Using Hooke’s law at small deformation gives
0,2)
/(0max 0→==x Y a a x d d λπ
σσ (34)
It follows Eq. (34) that
max 0
max 22a if Y
a Y ===
λπ
σπλ
σ (35)
Equations (32) and (35) show the theoretical fracture strengths, which depend on the interatomic potential. However, the theoretical cohesive strength is several orders in magnitude higher than that observed in experiments. It is the inconsistence between the theoretical and experimental values that drives the development of fracture mechanics.
2-2. Theoretical shear strength
In a similar way, we can estimate the theoretical shear strength. Figure 3 schematically shows the periodic lattice potential, and the equivalent value of the shear stress. The periodicity of the energy is assumed to be sinusoidal, so that
b
x
πττ2sin max =. (36)
In the limit of small shear strain x/d, where d is the interplannar spacing, Hooke’s law applies in the form
d
x μτ=, (37)
where μ is the shear modulus. Combining Eqs. (36) and (37) under small deformation, we have
5
2max μπμτ≈=d b . (38)
The theoretical shear strength is also several orders in magnitude higher than that observed in experiments. It is the inconsistence between the theoretical and experimental values that drives the development of dislocation theory. 3 Fracture Toughness
There are three criteria for toughness. They are obtained from tensile or bending tests with pre-cracked specimens.
3-1. Critical stress intensity factor
If a crack can be treated as a mathematic slit, the crack is called a sharp crack. The analysis based on linear elastic fracture mechanics shows that the stress field in a pre-cracked solid under mechanical loads shows a square-root singularity as a function of the distance from the crack tip, which means the stresses approach infinity at the crack tip. Stress intensity factors are introduced to measure the singularity levels. These are three types of loading on cracks, as shown in Fig. 4. If the crack faces are opened by a tensile force, it is a mode I crack or under mode I loading. If the crack faces are slid over one another by an in-plane shear force, it is a mode II crack or under mode II loading. If the crack faces are torn over one another by a tearing force (out-plane shear force), it is a mode III crack or under mode III loading. Stress intensity factors under mode I, mode II and mode III loading are denoted with K I , K II , and K III . For a finite crack within an infinite solid under remotely uniform mode I, II and III loads, as shown in Fig. 5, K I , K II , and K III are given by
a K I πσ∞
=22, (39a)
a K II πσ∞
=12, (39b) a K III πσ∞=32.
(39c)
The physical dimension of stress intensity factors is in units of (MPa)(m)1/2. The stress intensity factor for a special sample has to be numerically calculated. For most used sample geometry and size, the stress intensity factors have been calculated and listed in handbooks. Appendix A gives K-calculations for typically used specimens. A critical stress intensity factor is experimentally determined from the maximum load at fracture. The critical value of mode I stress intensity factor under plane strain condition is denoted by K IC and K IC is a material property, called the fracture toughness. If a sample does not meet the plane strain condition, the critical value of mode I stress intensity factor is usually higher than K IC . That is why K IC is used as a failure criterion in safety designs of industrial practice. Since K IC is a material property, the critical applied load causing fracture will be lower if the crack length is larger. Mathematically, the critical load is given by
a
K IC c
πσ=∞
,22. (40)
3-2. Critical energy release rate
The critical energy release rate, G C , is another fracture toughness parameter, which is defined as the energy required to propagate a unit area of the crack under mode I plane strain loading. Under plane strain condition, linear fracture mechanics provides the relationship between G and K I and, generally, between G and K I , K II , and K III ,
)
1/()(22
ν?=
Y K G I under mode I loading only, (41)
μν2)()
1/()()(2
2
22III II I K Y K K G +?+=, under mixed mode I+II+III loading (42)
where Y is the modulus of elasticity, ν is the Poisson ratio and μ is the shear modulus. With Equation (41), K IC can be converted to the energy parameter, G C .
3-3. Displacement or strain
For a material with sufficient ductility, we can use the critical crack opening displacement [designated as (COD)C or δC ], which is defined at the elastic-plastic boundary in front of a crack tip, as the toughness parameter. The critical crack opening displacement is related to the critical energy release rate as follows:
y C C n G σδ?=, (43)
where 2~5.11≤≤n . Consequently, when plane-stress conditions are prevalent, n=1, and n increases with increasing the plane strain component.
3-4. Energy balance in fracture
In Appendix B, we introduce the energy approach to fracture. The Griffith fracture theory links the critical energy release rate to the surface energy of the new created surfaces. If plastic deformation is associated with crack propagation, the Orowan and Irwin fracture criterion should be used.
Γ≡=>γ2C G G , Griffith fracture criterion, (44a)
Γ≡+=>)(2p C G G γγ, Orowan and Irwin fracture criterion,
(44b)
where p γ denotes the plastic work per surface area, which is the plastic work projected to the crack surface, and Γ represents the fracture toughness and is a material property.
4. Elastic constants
Elastic constants represent the resistance of a solid against elastic deformation. In linear elasticity, elastic constants link strains to stresses. Under small deformation, strains, ij ε, are defined as
???
?
??
????+??=i j j i ij x u x u
21ε, i, j=1, 2, 3 (45a)
where i x (i=1, 2, or 3) denotes an orthogonal Cartesian coordinate and i u (i=1, 2, or 3) is the displacement along the i x axis. In Eq. (45a), the repeated indices denote summation and this brief notation will be used hereafter unless special notice is given. For j i ≠, that is, for shear strains, Eq. (45a) gives only half of the shear strain, ij γ, as usually defined in engineering,
ij ij εγ2= j i ≠. (45b)
Eq. (45) indicates that there are six independent strain components.
In linear elasticity there are six stress components denoted by ij σ, which is the ith component of a force per unit area on a plane whose outward-drawn normal is parallel to the positive i x direction, as shown in Fig. 6. At mechanical equilibrium, there must be no net torque and net force in each infinitesimal volume element, which gives
ji ij σσ= if no internal torques are present, (46a)
033221
1=+??+??+
??i i
i i f x x x σσσ, i=1, 2, 3 (46b)
where i f denotes the ith component of a body force. If there is no body force inside a solid, i f =0 for i=1, 2, 3. Strains and stresses are both second-rank tensors.
In linear elasticity, Hooke’s law gives the relationship between strains and stresses, which reads as
kl ijkl ij c εσ=, i, j, k, l =
1, 2, 3 (47)
where ijkl c are elastic constants, which are a forth-rank tensor. Due to the symmetry of stresses and strains, elastic constants have the following symmetry:
jilk ijlk jikl ijkl c c c c ===. (48)
The change in the internal energy per unit volume, u , is given by
ij ij d Tds du εσ+=,
(49)
where s denotes entropy density, i.e., entropy per unit volume. Eq. (49) indicates that
s ij ij u ????
??
????=εσ. (50)
Hooke’s law can be re-written as
s
kl
ij s kl ij ijkl
u
c ???????????=??????????=ε
εεσ2 . (51)
Equation (51) gives another symmetry of elastic constants: klij ijkl c c =.
(52)
These symmetries indicate that there are only 21 independent elastic constants among the 81 ijkl c . To express Hooke’s law in matrix, the following matrix notations are introduced.
ij or kl 11 22 33 23 31 12 32 13 21 m or n 1 2 3 4 5 6 7 8 9
Then, Hooke’s law takes the matrix form:
??
???????????
?
??????????????????????????????????????????=????????????????????????????2113321231233322119998
97969594939291
898887868584838281797877767574737271696867666564636261595857565554535251494847464544434241393837363524333231292827262524232221191817161514131211211332123123332211εεεεεεεεεσσσσσσσσσc c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c . (53)
The 9x9 representation can be reduced to a 6x6 representation,
???
???
????
?
?????????????????????
???
??
???=????????????????????123123332211666564636261565554535251464544434241363534333231262524232221161514131211123123332211γγγεεεσσσσσσc c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c . (54)
The number of independent elastic components can be further reduced by crystal symmetry. In the crystalline lattice coordinate system, the elastic constants have the explicit forms:
{}??
????????
???????
?=444444111212121112121211000000000000000000000000
c c c c c c c c c c c c c for cubic crystals,
(55)
{}()????????????
?????
??=121121
444433133113
1121131211000000
0000000000
00000000
c c c c c c c c
c c c c c c for hexagonal crystals.
(56)
Elastic constants for some crystals are listed in Appendix C.
Note that the explicit representation of the elastic constant matrix depends on the choice of the coordinator system, which can be obtained by transformation of elastic constants. Consider two orthogonal coordinate systems, 321x x x and 321'''x x x . Let ij T be the direction cosine
between the i x ' and j x axes. The elastic constants, ijkl c ', in the 321'''x x x coordinator system can be calculated from ijkl c ,
ln T T c T T c km ghmn jh ig ijkl ='
(57a)
with summation over g , h , m and n understood. If a rotation tensor, ?, is introduced as
ln T T km mnkl =?, (57b)
Eq. (57a) can be rewritten as
mnkl ghmn ghij ijkl c c ??='. (57c)
Furthermore, with the introduction of the transpose T ijgh ? of ghij ?, Eq. (57c) re-expressed as
mnkl ghmn T ijgh ijkl c c ??='.
(57d)
Eq. (57d) can be explicitly expressed in (9x9) matrixes. In Appendix D, we give some details of the rotation transformation.
For isotropic materials, there are only two independent elastic constants. They are Young’s modulus, Y, shear modulus, μ, and Poisson’s ratio, ν, with the relationship of )(νμ+=12Y . In this case, elastic compliances are used and Hooke’s law is usually given by
?????
??????????????????????????????
???????=??????????????????123123332211123123332211100000010000001000000100010001σσσσσσμμμννννννγγγεεε////////////Y Y Y Y Y Y Y Y Y
for isotropic materials. (58)
5. Hardness
Hardness might not be a well defined material property due to complex stress field underneath the indenter tip. But, hardness is widely used in engineering practice because of its easiness in testing. In particular, the development of instrumented nanoindentation techniques has tremendously promoted the research on nanoindentation, which enables us to investigate the material properties at the nanometer scale. In instrumented indentation tests, load and displacement are recorded simultaneously, which provide more information about mechanical properties of a tested material. Nanoindentation test will be introduced later. Here, we briefly introduce conventional hardness tests.
Hardness may be regarded a measure of a material’s resistance to localized plastic deformation if plasticity is the deformation mechanism. Early hardness tests were based on
natural minerals with a scale constructed solely on the ability of one material to scratch another that was softer.
A qualitative and somewhat arbitrary hardness indexing scheme was devised, termed the Mohs scale, which ranged from 1 on the soft end for talc to 10 for diamond. Quantitative hardness techniques have been developed over the years in which a small indenter is forced into the surface of a material to be tested, under controlled conditions of load and rate of application. The depth or size of the resulting indentation is measured, which in turn is related to a hardness number; the softer the material, the larger and deeper is the indentation, and the lower the hardness index number. Measured hardnesses are only relative (rather than absolute), and care should be exercised when comparing values determined by different techniques.
Hardness tests are performed more frequently than any other mechanical test for several reasons: ?They are simple and inexpensive - ordinarily no special specimen need be prepared, and the testing apparatus is relatively inexpensive.
?The test is nondestructive - the specimen is neither fractured nor excessively deformed; a small indentation is the only deformation.
?Other mechanical properties often may be estimated from hardness data, such as tensile strength.
The common used hardness tests are summarized in Table 1. The following figure shows hardness of materials.
The Hardness Techniques
Appendix A: K Calculations for Typically Used Specimens
K Calculations for Typically Used Specimens
Appendix B: Energy Consideration of Fracture
In this appendix, we introduce the energy approach to fracture. For simplicity, fracture in brittle solids is discussed here.
Figure 1 shows an elastic solid rod having an original length, L , at the stress-free state. When a load, F , is applied to the solid, its length extends 1L Δ. If no cracking occurs inside the solid rod, the work done by the applied load is converted to the elastic strain energy, U . When the applied load is maintained unchanged, a crack is formed inside the solid, as shown in Fig. 1C. The formation of the crack reduces the stiffness of the solid rod. Thus, its length extends 2L Δ with respect to the length under the same load without any crack. In this case, the applied load does the work, 2L F W ΔΔ?=, and the elastic strain energy changes an amount of B C U U U ?=Δ. The driving force to nucleate the crack, E , is then defined as
)(U W U W E ?=?=ΔΔΔ.
(1)
When a crack is formed, two surfaces are created. The total surface energy of the created surfaces is given by
γA 2=Γ, (2)
where A denotes the area of a crack surface and γ is the surface energy. To nucleate the crack, the driving force must be larger than the total surface energy. It means
γA U W 2)(≥?Δ. (3)
If Fig. 1C is taken as the initial state, we can define the energy release rate for crack propagation. Under a constant load, F , the crack propagates a Δ and gives a change in the crack surface, A Δ, which reduces the stiffness of the rod such that its length extends 3L Δ. In this case, the applied load does the work, 3L F W ΔΔ?=, and the elastic strain energy changes an amount of C D U U U ?=Δ. The energy release rate, G , for crack propagation is defined as
A
U W A U W G A ???=ΔΔ?Δ=→Δ)(21lim 210, (4)
where 1/2 is added because a crack has two faces. In general, G is a function of A . Thus, when a crack propagates, its surface changes, A Δ. The driving force is calculated by
A G dA G U W A
Δ?≈=?Δ∫Δ22)(.
(5)
The crack propagation will cause a change in the total surface energy,
γA Δ?=ΔΓ2. (6)
To ensure the crack propagation, the driving force must exceed the resistance, which means
γA A G Δ?≥Δ?2. (7)
From Eq. (7), we can define the crack value of energy release rate,
γ2=C G .
(8)
Equation (8) is called the Griffith fracture criterion for brittle fracture.
Equations (1-8) are generally true. We may express them in a more sophistical manner. From thermodynamics, the internal energy per unit volume u can be expressed in the differential form using the index notation as
,Tds d du ij ij +=εσ (9)
where s is the entropy per unit volume; T is the absolute temperature; and σij , and εij are the components of the stress and strain tensors, respectively. The free energy per unit volume, f , is defined as
Ts u f ?=. (10a)
Then, we have
sdT d df ij ij ?=εσ. (10b)
The Gibbs energy per unit volume, g , is defined as
,Ts u g ij ij ??=εσ (11a)
Thereby yielding
sdT d dg ij ij ??=σε.
(11b)
For constant temperature, i.e., the isothermal condition, Eqs. (10b) and (11b) reduce, respectively, to
ij ij d df εσ=, (12)
ij ij d dg σε?=.
(13)
For elastic solids that have zero body forces, the kinematic and static equilibrium equations
are given by:
)(2
1
,,i j j i ij u u +=ε, (14)
0,=j ij σ, (15)
where i u are the displacements and the subscript “, j ” denotes the differentiation with respect to x j . Considering an elastic body, Π, without any cracks, we have the following principles of virtual work of an isothermal process for the body
0=?∫∫Π
Γ
ΠδΓδd f d u t i i ,
(16) 0=??∫∫ΠΓΠ
δΓδd g d t u i
i
, (17)
where Γ denotes the body boundary, t is the traction vector along the boundary with the component j ij i n t σ=, and n is the unit vector that is normal to the boundary and outwards the elastic body. The principles of virtual work are easily proved. We take Eq. (16) as an example. Applying the divergence theorem to the first term of Eq. (16) gives
()()()Π+=Π=Γ=Γ∫∫∫∫Π
Π
Γ
Γ
d u u d u d n u d u t j i ij i j ij j
i ij j i ij i i ,,,δσδσδσδσδ. (18a)
Using the static equilibrium condition, we simplify Eq. (18a) to
Π=Γ∫∫Π
Γ
d u d u t j i ij i i ,δσδ.
(18b)
Then, using Eqs. (14) and (12), we have
Π=Π=Π=Γ∫∫∫∫Π
Π
Π
Γ
d f d d u d u t ij ij j i ij i i δδεσδσδ,.
(18c)
Let us introduce the following two isothermal potential energies:
∫∫?=Π
Γ
ΠΓ,~
d f d u t P i i F
(19)
where the overhead “~”denotes the prescribed tractions on the boundary, and
∫
∫??=Π
Γ
ΠΓd g d t u P i i G ~, (20)
where the prescribed quantities on the boundary are displacements. Then, the principles of virtual work for a crack-free elastic medium can be rewritten as
0=?=∫∫Π
Γ
ΠδΓδδd f d u t P i i F ~, (21)
0=??=∫
∫Π
Γ
ΠδΓδδd g d t u P i i G ~. (22)
If the generalized force, P , and the generalized displacement, Δ, are used, then the changes in the total free energy, F , and the total full Gibbs energy, G , for the entire sample are given by
Δ=Pd dF , (23) dP dG Δ?=. (24)
Equations may be understood as the principles of virtual work for the case that the generalized force, P , and the generalized displacement, Δ, are used.
Now, consider an elastic medium containing a crack. Adding the energy change associated with the crack extension into each of Eqs. (23, 24) leads to
JdA Pd dF 2?Δ=, (25)
JdA dP dG 2?Δ?=, (26)
where A is the area of the crack face, and J is the energy release rate for crack propagation defined as
P
A G A F J ???
????=???????=Δ????2121.
(27)
Alternatively, the energy release rate can be evaluated by
A
P A P J G F ?????=?=2121. (28)
For two-dimensional problems, if the crack grows along the crack plane (along the x 1-axis), the energy release rate can also be calculated from each of the following two path-independent J -integrals as long as the integration path encloses the crack tip:
(),,∫?=Γ
Γσd u n fn J i j ij 11 (29)
().,∫+=Γ
Γσd u n gn J i j ij 11
(30)
Rice (1968) developed Equation (29), which is called Rice’s J-integral. A J-integral path starts at the lower crack face and around the crack tip anti- clockwise. J-integral is path-independent. We take Eq. (29) as an example to improve it. We make an integration contour excluding the crack tip and composed of four parts, 1Γ, upper Γ, lower Γ, and -2Γ, as shown in Fig. 2. A minus sign is added on 2Γ because the integration direction is clockwise in the enclosed contour. Along the
Fig. 2. J-integral contour.
upper and lower crack faces, traction is free and 01=n . The integration along upper Γ and lower Γ is zero. Thus, we have
()()∫
∫
Γ?ΓΓ?Γ+Γ+ΓΓ?=Γ?2
12
11,1
1,1
d u n fn d u n fn i j ij
i j ij
lower upper σ
σ
. (31)
On the other hand, applying the divergence theorem gives
().0)()()(1,1,11,11,12
1∫∫∫
ΠΠΓ?Γ+Γ+Γ=Π???
?
??????????????=Π?????????????=Γ?d x u x u x f d x u x f d u n fn j ij i j i ij ij ij j i ij i j ij lower upper σσεεσσ (32)
Combining Eq. (31) and Eq. (32) yields
()02
11,1=Γ?∫Γ?Γd u n fn i j ij σ or ()()∫
∫ΓΓΓ?=Γ?=2
1
1,1
1,1d u n fn
d u n fn J i j ij i j ij σσ. (33)
We can also take thermal stresses into account. Iesan and Scalia (1996) discussed thermoelastostatic deformations in detail. In thermoelastostatics, thermal stresses are treated as “body forces”. In the absence of time dependence, the entropy does not change with time. Temperature is controlled by the steady state heat transfer equation, which ignores the temperature change induced by the mechanical and electrical fields. We name this approach the pseudo-isothermal approach because the temperature field is calculated only from heat transfer and not affected by mechanical fields. Once the temperature field is available, the mechanical fields can be calculated in a way similar to the isothermal process.
必修三 1航行到美洲的北欧海盗 北欧海盗是第一批到达美洲的欧美人。早在哥伦布起航之前，他们就已经到达那里了。 北欧海盗的祖先来自于斯堪地那维亚半岛。公元8世纪到10世纪期间，他们控制着北欧海绵和沿海地区。大约到公元900年，北欧很多地方都有海盗居住。公元982年，冰岛生活着多达一万人的北欧海盗，就在此时，一个叫红发埃里克的人决定走向西远航。 根据冰岛和挪威的传说，红发艾里克银犯谋杀案而惹上麻烦，并被迫离开冰岛。埃里克到达达格陵兰岛后，发现他登陆的地方可以居住，返回冰岛，告诉人么哪有管格陵兰岛的事情，病说服一些人与他一起回到格陵兰岛，埃里克再次起航时，有25艘船与他同行，但其中只有14艘最终到达格陵兰岛。 红发埃里克登上格陵兰岛不久，一个叫比阿尼的人也从冰岛起航来寻找埃里克一行人。比阿尼希望找到和埃里克在一起的父亲，但大风使他偏离航线，刮到一个不知名的地方，从哪里他最终抵达格陵兰岛。 1002年红发埃里克的儿子利夫打算继续向西航行，他和比阿尼一同商量他们的在行计划。利夫依照比阿尼的指点。据说航信到了现在的加拿大海岸，他又继续南行至现在叫纽芬兰的岛屿。 我们从挪威和冰岛记载下来并流传几个世纪的传说中得知红发埃里克和利夫的事迹。他们是记载中最早航行到达美洲的欧洲人。 3水下世界-------观赏海洋生物的最佳地点 这里有北极熊，还有一座真正的冰川！你只能看见冰山水上的一小部分，而水下部分是水上部分的三倍。你可以再给海豹喂食时观看海豹，看看那些不爱运动却非常友好的动作敏捷的企鹅。你一定会爱上他们的！ 海底 看看世界上最美的珊瑚和最奇异的鱼类，看鱼飞翔着，闯过水面，与其他鱼类相比，他们不算绚丽多姿，但游姿却很美。 海洋剧院 看着聪明的海豚，精彩的表演每两小时一场。 探索他 这里是专为小孩子设计的，在这里，孩子们可以亲手接触摸螃蟹和其他小动物，还可以在这个令人兴奋的环境里学习到关于海滩上日常生活的知识。 虚拟航海 这是我们水管最新，最具有吸引力的活动，来和我们一起进行模拟航行吧！到海底走一走，看一看世界上最奇异的鱼。 最吵的鱼：有些鱼发出的声音几乎是你讲话声音的两倍，你绝对不会找到比他们更吵闹的鱼。 最漂亮的鱼：有的鱼用身体发光一心其他鱼靠近人后吃掉他们，这些的嘴巨大无比，可以吃掉和自己体积一样大的鱼。要当心哦！ 最小的鱼:仔细找找这种世界上最小的鱼，他们还不及你家的苍蝇大。 和海豚一起游泳！直接面对海洋中最具有杀伤力的动物——大白鲨 快来参观吧，还有好多动物呢！22日前特价，尽快定票吧！每天早上10点开门。晚上7点关门 4海洋故事 B三年前，我遇到了一间可怕的事。6个小时的恐惧情形让我身心俱毁。你现在回认
吉林恒联编号: 精密铸造科技有限公司技术操作规程生效日期: 年月 编制: 审核： 竖炉烘干机岗位操作规程批准: 一、适用范围：本规程适用于竖炉烘干岗位的操作。 二、主要设备参数 1、干燥机 3、运输皮带机 三、技术操作要求 ①烘干炉操 1、首次引煤气烘炉操作 （1）新建或大修后的烘干炉在点火之前应进行烘炉。 （2）烘炉前首先将煤气引至烘干混合机前煤气管道盲板处。打开烘干混合机前煤气管道盲板前煤气放散阀，向厂内通往烘干混合机的高炉煤气主管道中通氮气吹扫，待煤气放散阀冒氮气10分钟后，关闭厂内高炉煤气主管道手动蝶阀，打开手动盲板阀，然后，再打开手动蝶阀，引煤气至烘干混合机前煤气管道盲板处，关闭烘干混合机前煤气管道盲板前煤气放散阀。（3）烘炉操作 烘炉的作用主要是蒸发耐火砌体内的物理水和结晶水，并提高砌砖泥浆的强度和加热砌体，使炉体达到要求的一定温度，以便投入生产。 烘炉应严格按烘炉曲线进行，一般可分为三个阶段： a低温阶段：烘烤温度从常温（20℃）至300℃。 这时主要是蒸发烘干炉砌体中的物理水。升温要求缓慢(10℃/h)，以防止急骤升温而造成耐火砖及砖缝开裂，并在300℃时需要有一定的保温时间（一般为24小时）。这阶段一般用木
柴。 b中温阶段:烘烤温度在300℃～600℃。 主要是脱去砌体耐火泥浆生料粉中的结晶水。升到500℃时须要保温8～10小时，到600℃时为彻底使砌体泥浆发生相变，使其强度提高，因此要保温8～10小时，中温阶段升温可稍快(15℃～20℃/h)。这阶段一般用低压煤气。 c高温阶段：烘烤温度600℃～900℃ 主要是加热砌体，升温速度可快些(20℃/h)，为了使砌体的温度达到均匀，也可进行保温（一般为8小时）。这阶段可使用高压煤气。 烘烤温度再往上升，升温速度可以加快到30-50℃/h，直到生产所需要的温度。 900℃ 20℃30 54 68 78 85 95 105小时 竖炉烘炉曲线图 2、正常生产中的引煤气点火操作 （1）引煤气前通知作业长到现场，得到中控同意后通知煤气加压站做好送气准备； （2）检查煤气放散阀是否在开位，煤气烧咀前阀门是否关闭，盲板前电动煤气蝶阀关闭；（3）向烘干混合机前煤气管道内通氮气吹扫，待煤气放散阀冒氮气十分钟后，倒盲板引煤气至烧咀前阀门处； （4）然后进行煤气检验，合格后方可进行点火； （5）点火时煤气压力要大于10000Pa；在炉膛温度大于750℃可直接引煤气点火，否则要用明火点燃。点火时要缓缓开启烧咀阀门，待煤气点着后，将煤气放散阀关死，并调节煤气与空气比例，使燃烧正常进行。 点火时要注意：
球团生产工艺介绍 球团生产工艺是一种提炼球团矿的生产工艺，球团与烧结是钢铁冶炼行业中作为提炼铁矿石的两种常用工艺。球团矿就是把细磨铁精矿粉或其他含铁粉料添加少量添加剂混合后，在加水润湿的条件下，通过造球机滚动成球，再经过干燥焙烧，固结成为具有一定强度和冶金性能的球型含铁原料。 一、球团生产工艺的发展 由于天然富矿日趋减少，大量贫矿被采用；而铁矿石经细磨、选矿后的精矿粉，品位易于提高；过细精矿粉用于烧结生产会影响透气性，降低产量和质量；细磨精矿粉易于造球，粒度越细，成球率越高，球团矿强度也越高。综上所述原因，球团生产工艺在进入21世纪后得到全面发展与推广。 如今球团工艺的发展从单一处理铁精矿粉扩展到多种含铁原料，生产规模和操作也向大型化、机械化、自动化方向发展，技术经济指标显著提高。球团产品也已用于炼钢和直接还原炼铁等。球团矿具有良好的冶金性能：粒度均匀、微气孔多、还原性好、强度高，有利于强化高炉冶炼。 二、球团法分类 1、高温固结： （1）氧化焙烧：竖炉、带式机、链篦机-回转窑、环式焙烧机。 （2）还原焙烧：回转窑法、竖炉连续装料法、竖炉间歇装料法、竖罐法、带式机法。（3）磁化焙烧：竖炉法 （4）氧化-钠化焙烧：竖炉法、链篦机-回转窑。 （5）氯化焙烧：竖炉法、回转窑法。 2、低温固结： （1）水泥冷粘结法 （2）热液法 （3）碳酸化法 （4）锈化固结法 （5）焦化固结法 （6）其他方法 三、球团原理 球团生产一般流程：原料准备→配料→混匀(干燥)→造球→布料→焙烧→冷却→成品输出
球团焙烧过程：干燥→预热→焙烧→均热→冷却 四、球团工艺流程图 球团车间平面分布图 新配料料场新配-1 新配-2 新配-3 新配-4 新配-5 老配-2 老配-1 老配料仓 老配-3老配-4 烘干出料 润磨出料 润磨 室 1#烘干室 1#水泵 房办公室休息室 球-4 球-1 造球室 成-1 1#落地仓 1#链板 1#环冷机 1#回转窑 1#链篦机 1#布料 球-3 球-2 返-3 返-2 返-6 返-5 返-4 球-6 2# 布料 2#链篦机2#回转窑 2#环冷机 2# 链板 成-3成-4 2#落地仓 维修区域 维修值班室 球-5 球 -5 转 运站老配料料场 2#水泵房 喷煤系统2# 烘干室 主控楼 北
精心整理 玻璃钢制作工艺流程 首先在制作好的模具清理表面的垃圾灰尘，打好8#蜡，刷上一层“33#胶衣”的东西，表面光滑，就是这个胶衣的效果，等它干了后，就开始用调配好的玻璃钢树脂和玻璃纤维毡开始“积层”。（其中调配玻璃钢树脂是根据其产品的强度和耐火程度来调配，还要添加一些固化剂，钴水之类的）。玻璃钢第一层积完，等它干了后，再用纤维布继续往下积层，一般强度的：纤维布积4到5层就足够，积的过程是积1到2层就要等干一次大约大半个小时。积层：是一边用刷子蘸玻璃钢树脂涂在就起模，来的。 然一、生产准备工序 设备、工装、工具等生产装备明细： 1.玻璃钢模具 2.铲刀 3.毛刷
4.吹尘枪 5.干净毛巾 6.海绵 7.8#黄蜡 8.树脂 9.玻璃纤维 10.胶衣 11. A. B. C. D.应用铲 .清 E. 5--20 匀, F. 干净, A. 工使用面。 B.在用干净毛巾进行擦拭蜡层作业时,应将保留在模具面上的蜡层彻底清除干净并将模具抛光亮,以免多次在模具面上积蜡造成蜡层擦拭不掉形成蜡垢,从而导致模具哑光和影响产品脱模和表面效果。 二.涂刷胶衣层工序 设备工装工具等生产装备明细
1.玻璃钢模具 2.毛刷 3.水瓢 4.胶衣 5.固化剂 6.温度计 生产加工工艺 A. B. C.. D. E. 执行。 A. B. C. 三．定型铲泡工序 设备工装工具等生产装备明细： 1.玻璃钢模具 2.玻璃纤维腻子 3.固化剂 4.刮板或灰刀
5.毛刷 6.水瓢 7.02#玻璃纤维布 8.191#树脂 9.铲刀或刀片 10.60#--240#砂布 生产加工工艺： A. B. , C. 02# D. 具面. A. B. C. 四．增强层制作工序 设备工装工具等生产装备明细： 1.玻璃钢模具 2.毛刷 3.水瓢 4.191#树脂
必修一 Learning to learn Questionnaire 问卷，调查表 Matter 要紧，有重大关系 Partner 合作者，搭档 Unit 1 Warm up Lifestyle 生活方式 *shepherd 牧羊人 Peaceful 平静的，和平的 Relaxing 轻松的，放松的 Stressful 充满压力的，紧张的 Suppose 认为，猜想 Lesson 1 *series 系列节目；系列 TV series 电视连续剧 Cartoon 卡通片，动画片 Talk show 谈话节目，现场访谈 *complain 抱怨；投诉 *couch 长沙发，睡椅 Couch potato 终日懒散在家的人 Switch 转换，转变 Switch on 把开关打开，接通 Switch over 转换频道，转变 Switch off 把关掉，关上 BBC= British Broadcasting Corporation 英语广播公司 Portable 轻便的，手提（式）的 Remote 遥远的 Remote control 遥控 *workaholic 工作狂 Paperwork 日常文书工作 Alarm 警报，警告器 Alarm clock 闹钟 Go off （铃，爆竹等）响 Take up 占据 Be filled with 充满着 Urgent 急迫的，紧急的 Document 公文，文件 Midnight 午夜，半夜 Bored 厌烦的，不感兴趣的 Lesson 2 Stress 压力 Studio 演播室，工作室Expert 专家 Suffer 遭受（痛苦），感到疼痛Suffer from 忍受，遭受Pressure 压力 Social 社交的，社会的 Reduce 减少，降低 Organize 组织 Diet 饮食，节食 Prefer 更喜欢，宁愿 Stand 忍耐，忍受 Lesson 3 Volunteer 志愿者 Graduate 毕业 Minus 零下，负 Basin 脸盆 Challenge 挑战 Support 支持，支撑 Dial 拨（电话号码） Design 设计 Advertisement 广告Presentation 表演，展示 *slove 解决，解答 Lesson 4 Accountant 会计，会计师Tube （英）地铁 Crowded 拥挤的 Nearby 附近的 在附近 Otherwise 否则，另外Forecast 预报，预测 Crowed 人群，一伙人 Lung 肺 Sickness 疾病 Distance 距离 Distance learning 远程学习Cigar 雪茄烟 Communication Workshop At the moment 此刻，目前Over the years 数年间 *survey 调查 Classical 古典的 Mini-skirt迷你裙，超短裙Formal 正式的，合礼仪的Cycle 骑自行车
必修一Learning to learn Questionnaire问卷，调查表 Matter要紧，有重大关系 Partner合作者，搭档 Unit 1 Warm up Lifestyle生活方式 *shepherdxx Peaceful平静的，和平的 Relaxing轻松的，放松的 Stressful充满压力的，紧张的Suppose认为，猜想 Lesson 1 *series系列节目；系列 TV series电视连续剧 Cartoon卡通片，动画片 Talk show谈话节目，现场访谈 *complain抱怨；投诉 *couchxx发，睡椅 Couch potato终日懒散在家的人
Switch转换，转变 Switch on把开关打开，接通Switch over转换频道，转变Switch off把关掉，关上 BBC=BritishBroadcastingCorporation 英语广播公司 Portable轻便的，手提（式）的Remote遥远的 Remote control遥控 *workaholic工作狂 Paperwork日常文书工作 Alarm警报，警告器 Alarm clock闹钟 Go off（xx，爆竹等）响 Take up占据 Be filled with充满着 Urgent急迫的，紧急的Document公文，文件 Midnight午夜，半夜 Bored厌烦的，不感兴趣的Lesson 2
Stress压力 Studio演播室，工作室Expert专家Suffer遭受（痛苦），感到疼痛Suffer from忍受，遭受 Pressure压力 Social社交的，社会的 Reduce减少，降低 Organize组织 Diet饮食，节食 Prefer更喜欢，宁愿 Stand忍耐，忍受 Lesson 3 Volunteer志愿者 Graduate毕业 Minus零下，负 Basin脸盆 Challenge挑战 Support支持，支撑 Dial拨（电话号码） Design设计 Advertisement广告
Unit 1 Lifestyles Warm-up Tapescript 1 Football player: Being famous isn’t easy, you know. I travel a lot – I have matches in different countries. But my job is exciting, very exciting! I love the matches, the people cheering, know what I mean? 2 Student: My dad says these are the best days of my life –but I’m not so sure! You know, I’ve got lots of work to do and there’s not much time really. I also play football for the school team and we have to do training three nights a week. 3 Shepherd: I love the animals and I love nature. It’s peaceful, and there’s no one to tell me what to do. But it’s not so good when the weather’s bad! 4 Business manager: I’m very busy, and I don’t have time to see my husband and children. Mmmm and my life is very stressful, I suppose. I mean, I have to deal with lots of money. But I find it really exciting. 1 A Perfect Day? A Couch Potato Forty-three-year-old Brian Blakey from Birmingham is sitting on his sofa and telling me about his perfect day.
球团工艺及生产
————————————————————————————————作者：————————————————————————————————日期：
球团工艺及生产 把细磨铁精矿粉或其他含铁粉料添加少量添加剂混合后，在加水润湿的条件下,通过造球机滚动成球，再经过干燥焙烧,固结成为具有一定强度和冶金性能的球型含铁原料。??球团矿生产的流程:? 一般包括原料准备、配料、混合、造球、干燥和焙烧、冷却、成品和返矿处理等工序，如下图所示。 球团矿的生产流程中,配料、混合与烧结矿的方法一致;将混合好的原料经造球机制成10－25mm的球状。 1.球团矿的概念?把细磨铁精矿粉或其他含铁粉料添加少量添加剂混合后，在加水润湿的条件下,通过造球机滚动成球，再经过干燥焙烧,固结成为具有一定强度和冶金性能的球型含铁原料。 球团生产与烧结生产一样，是为高炉提供“糖料”的一种加工方法,是将细磨精矿或粉状物料制成能满足高炉冶炼要求的原料的一个加工过程。将准备好的原料（细磨精矿或其他细磨粉状物料、添加剂等）,按一定比例经过配料、混匀，制成一定尺寸的小球，然后采用干燥焙烧或其他方法使其发生一系列的物理化学变化而硬化固结，这一过程即为球团生产过程，其产品即为球团矿。球团矿分酸性球团矿和碱性球团矿。由于酸性球团矿生产操作较易控制,且品位高，强度好,同时，高炉冶炼也需要酸性球团与高碱度烧结矿配合使用。 ?2．球团矿生产迅速发展的原因：?◆天然富矿日趋减少,大量贫矿被采用。 铁矿石经细磨、选矿后的精矿粉,品位易于提高。
过细精矿粉用于烧结生产会影响透气性,降低产量和质量。?细磨精矿粉易于造球，粒度越细，成球率越高,球团矿强度也越高。?◆球团法生产工艺的成熟。?从单一处理铁精矿粉扩展到多种含铁原料。?生产规模和操作也向大型化、机械化、自动化方向发展。 技术经济指标显著提高。 球团产品也已用于炼钢和直接还原炼铁等。 ◆球团矿具有良好的冶金性能:粒度均匀、微气孔多、还原性好、强度高，有利于强化高炉冶 ?球团矿生产中的主要设备： 炼。? 圆盘造球机:将焦炭粉、石灰石粉或生石灰、铁精矿粉混合后，输入圆盘造球机上部的混合料仓内，均匀地向造球机布料,同时由水管供给雾状喷淋水，倾斜(倾角一般为40一5０°)布置的圆盘造球机，由机械传动旋转，混合料加喷淋水在圆盘内滚动成球。 【烧结设备】圆盘造球机工作原理 ?圆盘造球机用于铁矿粉造球，它是各类球团厂的主要配套设备之一。将焦炭粉、石灰石粉或生石灰、铁精矿粉混合后,输入圆盘造球机上部的混合料仓内，均匀地向造球机布料,同时由水管供给雾状喷淋水，倾斜（倾角一般为4０一5０°）布置的圆盘造球机，由机械传动旋转,混合料加喷淋水在圆盘内滚动成球，通过粒度刮刀将球的粒度控制在5一15毫米。造好的生球落入输送皮带上,经辊轴筛进行筛分，小于５毫米和大于15毫米的返回到混合机。?主要用到的自动化产品:断路器、接触器、电动机?带式焙烧机：带式焙烧机工艺使球团焙烧的整个工艺过程——干燥、预热、焙烧、冷却都在一个设备上完成,具有工艺过程简单、布置紧凑、所需设备吨位轻等特点，为工厂缩小占地面积、减少工程量、实现焙烧气体的循环利用以及降低热耗和电耗创造了条件。? 主要用到的自动化产品:断路器、接触器、电动机 带式焙烧工艺介绍 带式焙烧工艺可以说是受带式烧结机的启示而发展起来的。?1、带式焙烧机不同于带式烧结机 细磨铁精矿球团的焙烧和铁矿粉的烧结,在固结原理上有着本质上的不同,致使其在工业 生产技术上也有着很大的不同。因而要想把一般的烧结机改造成带式焙烧机将是十分复杂和困难的。?带式焙烧机从外形上看,和烧结机十分相似，但在设备结构上存在很大的区别。如,台车的结构和支架的承力，风箱的分布和密封的要求.上部炉罩的设置和密封,风流的走向（不像烧结机那样是单一的抽风,而是既有抽风又有鼓风)，布料方式,成品的排出和台车运行速度等，都不相同,特别是本体的材质更是完全不同。为了能长期安全地承受最高焙烧气体的温度（≥１３00 ℃），而不得不采用耐高温性能极好的特殊合金钢。在国外带式焙烧机发展的过程中，曾因材质不过关而一度受挫,而使得同时正在开发的链篦机—回转窑得到了极大的发展。因为链篦机—回转窑工艺是将焙烧过程的最高温度段放在设有耐火炉衬的回转窑中进行,这样就顺利解决了在高温焙烧中的材质问题。而带式焙烧机在使用铺底铺边料和台车采用耐高温合金特殊钢的材质后才得以过关并获得大发展。 ２、带式焙烧机工艺的优点 1）球团焙烧的整个工艺过程——干燥、预热、焙烧、冷却都在一个设备上完成，具有工艺过程简单、布置紧凑、所需设备吨位轻等特点,为工厂缩小占地面积、减少工程量、实现焙烧气体的循环利用以及降低热耗和电耗创造了条件。?２）能适应扩大生产规模的要求和实现大型化的要求。其最大已达到750 m2，单机产量达50０万t以上。 3）对原料的适应性比竖炉强。这是因为在整个焙烧过程中,球团都处于静料层状态，不会因升温过程中球团本身强度的变化(时高时低）和球与球之间的相对运动而产生粉末。因而带
玻璃工艺品的制作方法 玻璃主要成份是矽砂、苏打灰、碳酸钠、碳酸钾、石灰及铝土、铅丹等，种类很多。一般主要成份为钠玻璃属之；钾玻璃，制瓶玻璃属之；铅玻璃，仪器玻璃属之。新竹地区的矽石出产于关西一带，但近年来铁份含量偏高，品质稍差，所以大多仍由澳洲及马来西亚进口。首先先矽砂、石灰、苏打灰等放入坩锅窑中，在一千四百五十摄氏度的高温下十六小时，待混合融解成浓稠液体后，臵于模具上，使之成形，再经十二小时徐冷后加式处理。期间施以喷沙、添色、嵌入金箔、磨花、雕刻、药水浸泡等装饰技巧。又在烧制时使用各种金属发色剂，制作出来的玻璃刚具有不同的颜色。 玻璃艺吕的成形法： 玻璃一般玻璃原料燃烧溶解后都形成液体粘稠液，要使其冷却成形，大都采用型吹法，使用各种材质的模型，如木材、粘土、金属等预先制成所需要的型器，把融化的玻璃液倒入模型内，待冷却后再将模型打开即成，一般用于吹玻璃无法制成的器具，大部分的工厂都采用此种方法，可以大量生产。 另一种为吹气成型法，即吹玻璃，就是取出适量的玻璃溶液，放于铁吹管的一端，一面吹气，一面旋转，并以熟练的技法，使用剪刀或钳子，使其成型。 常用技法 冷工制作法 1.彩绘以彩绘颜料，在室温下于玻璃物表面描绘图画，有些需加热固定，有些则不需。过程中也可以加上金箔、银箔熔成的金属颜料，称为饰金彩绘。 2.釉彩是一种需要再加温的彩绘声绘色的技法，在玻璃物表面，以釉彩颜料绘制图样，然后再臵入熔炉加温固定颜料，避免剥落。 3.镶嵌以有凹槽之铅条为线框架，组合成千上万片的彩色玻璃板的技法，需绘制小型平面图，根据平面图绘制等尺寸的草图，确定每一种颜色的造型与尺寸，正确切割玻璃板，以铅线熔焊成大块面镜。 4.版画无须加温的冷作，利用喷砂或磨刻的技法，将图刻印在玻璃板上，加以制版，以版画机或滚筒上色，在棉纸或水彩纸上压制成版画。 5.浮雕在双层或多层颜色套料的玻璃，浮雕出立体图案透露出底色，形成浮雕效果。 6.切割运用切割轮，在玻璃物上切割纹饰、块面，线条等装饰，或大面切割成造型，有时双色套料玻璃，因表现内外不同的颜色的特殊效果。 7.磨刻以钻石或金属雕刻，或雕刻笔等雕刻工具在玻璃表面画线装饰花纹与图样的技法，因使用工具的不同，可分为轮刻、点刻、平刻等种技法。 8.酸蚀在玻璃板绘制图形、勾勒线条，再经化学酸剂分阶段蚀出深浅不同的图案。 9.喷砂先以胶带粘满整个玻璃物，在以刻刀镀刻去掉图案不要的部分，臵入喷砂机，运用金刚砂的高喷射力，在玻璃上做出雾状效果。 10.研磨以旋转轮盘为研磨台，混合水与金刚砂，磨平刨光玻璃作品。 11.刨光以旋转皮轮为平台，将玻璃至于其上，磨光刨光大块平面。
北师大版高中英语单词表 北师大版高中英语模块一单词表（English）Unit 1Unit 2Unit 3 Unit1 Learning to learn questionnaire 问卷，调查表；matter要紧，有重大关系；partner搭挡,合作者； Warm-up lifestyle生活方式；shepherd牧羊人； peaceful和平的；平静的；relaxing轻松的，放松的；stressful轻松的，放松的；suppose认为，猜想 ----------------------- Lesson 1 series连续；系列，丛书TV series电视连续剧cartoon卡通片,动画片talk show谈话节目，现场访谈complain抱怨,投诉couch睡椅,长沙发 couch potato终日懒散在家的人switch转换,转变 switch on把开关打开,接通switch off把关掉,关上switch over转换频道,转变play戏剧,短剧 BBC英国广播公司portable轻便的,手提(式)的remote遥远的remote control workaholic工作第一的人,专心工作的人 paperwork日常文书工作alarm警报,警告器 alarm clock闹钟(爆竹,铃等)响 go off
take up占据be filled with充满着urgent急迫的,紧急的personal私人的,个人的document公文,文件midnight午夜,半夜 bored厌烦的,不感兴趣的 ----------------------- Lesson 2 stress压力studio工作室,演播室expert专家suffer感到疼痛,遭受(痛苦) suffer from 忍受, 遭受pressure压力 social爱交际的;社交的reduce减少降低organize组织diet饮食,节食 stand忍耐，忍受prefer更喜欢,宁愿 ----------------------- Lesson 3 volunteer志愿者graduate毕业 minus负，零下basin水盆,脸盆challenge挑战support&支持;支撑 dial拨(电话号码) design&设计advertisement广告presentation表演，展示solve解答,解决 ----------------------- Lesson 4 accountant会计,会计师tube（英）地铁crowded拥挤的nearby附近的；在附近
球团竖炉 一种用于焙烧冶金球团的竖炉，属于冶金设备的技术领域。它包括由炉墙组成的炉膛，设于炉膛下端的锁风卸料装置，炉膛上部的球团料进口和设于炉膛内中部的破碎辊，炉墙下部设有供风喷口，炉膛内设有与炉膛内外相通的燃料管道，所述燃料管道炉膛内部分设有燃料喷嘴。它结构简单，燃料直接在炉内燃烧，炉宽方向温度均匀，热效率高，焙烧带供热足，球团产量高，质量均匀。 包括由炉墙(1)组成的炉膛，设于炉膛下端的锁风卸料装置(8)，设于炉膛上部的球团料进口和设于炉膛内中部的破碎辊(5)，其特征在于：炉墙(1)下部设有供风喷口(6)，炉膛外设有与炉膛内相通的燃料管道(3)，所述燃料管道(3)炉膛内部分设有燃料喷嘴(2)。 ★TCS球团竖炉专利技术简介 TCS球团竖炉突破了竖炉大型化这一国际难题，成功地利用自身余热将助燃风温度预热到230℃以上。经河北省科学技术厅组织的国内球团专家委员会进行技术成果鉴定，确定为国内先进水平，取得了投资省、占地省、能耗低、成本低、质量高的实际生产效果，属于钢铁企业高炉精料的“短平快”技改项目。目前TCS球团竖炉的开发技术已走向系列化、大型化，年产6.6万吨、10万吨、30万吨、50万吨、60万吨、70万吨、80万吨已经实施应用，100万吨已设计完成。我公司“TCS球团竖炉”已发展到第六代技术，其中节能型TCS球团竖炉直接利用生产过程产生的600～800℃冷却风作助燃风，充分利用余热，减少了热量损失，节约了能源。 ★TCS球团竖炉专利技术特点： 1、炉顶气动布料器，结构简单，工作可靠。 2、上下两层烘干床，烘干面积大，且气体温度可分区控制，因而可实现变温变向慢速干燥，减少了过湿现象和爆裂现象。 3、烘干床具有气筛和固定筛作用，可将大部分粉末和返矿提前分离并排出炉外，改善了焙烧带料柱透气性和气流分布，增强了对原料和操作波动的适应能力，使TCS球团竖炉的利用系数高达7-8.33（t/m2.h）。 4、焙烧带喷火口和燃烧室置于炉子内部，从内向外烧，充分利用边缘效应，提高了喷火口对面外墙附近低温区域的气流量和温度，使整个焙烧带气流和温度分布趋于均匀合理。 5、环型焙烧带不需加大焙烧带的宽度，即可方便设计出较大焙烧带面积，有利于竖炉的大型化。 6、燃烧室、焙烧带、干燥带、防过湿带可分区独立计算机检测和控制，大大提高了操作精度，通过调试和操作可使各项参数达到最佳。
Lesson 1 安格斯*伊德莱采访前百万富翁查尔斯雷时。查尔斯说：‘谁想当百万符文呢？我不想很多人一心想成为百万富翁。他们花一半的时间追求致富的方法。另一半的时间则在琢磨一旦富裕起来要做些什么。但是，是否所有的百万富翁真正得到了他们要实现的目标前所想的幸福呢、其实，有些人成为百万富翁后还有其他的烦恼———他们拼命的到的财富，怎样拼命以确保不在失去这些财富。 但是也有人把自己的百万资产置于一边，选择不同的人生的路，查二斯就是这样的一个人。 16年前，查尔斯是大学教授，住着一有六个卧室的房子，有着百万的资产，而现在住的则是小宿舍的房间，家具都是二手的，没有任何的迹象表明查尔斯是个富人没房间外有个小花园，花园里种着几个果树，查尔斯自己种植蔬菜和花，衣服和家具的用品都是从慈善点买的。 但是查尔斯喜欢折中改变。查尔斯对这样的富人的生活方式感到高兴。他不在想做在许多人一无所有的情况下自己拥有一切的那种人，他选择了了把自己的钱财送给别人，他说这样会给他带来快乐。 查尔斯说：几年前，我曾经是个百万富翁，但是我意识到世界上还有许多的忍受疾饿的穷人。因此他把所有的钱财捐给了慈善机构，当只剩下两千美元的时候，他将小额的纸币散发给当地的贫困街区的穷人，难道他真的举得自己像圣诞老人吗？查尔斯说这么做具有乐趣。 查尔斯相信很多人盼望着挣一大笔钱解除烦恼，然而，大多数的人根本没有挣多那么多的钱，查尔斯*格雷决定退出富人网，他发现拥有少量的钱会给人自由，难道真的没有什么让他依旧怀念的吗？查尔斯答道：没有，我现在更快乐了。什么也不可能在回到富人的行列——决不可能。 Lesson 3 五元钱能做什么？或许你觉得做不了什么，你如果对买包糖果或甜点不感兴趣的话，买课树怎样？确切的说，一棵树在黄河岸迹的树。 每年，大约有16亿吨泥土流入黄河——这条中国国第二大河流，这些泥土中含有保持该大自然平衡的物质，经年累月，大量的泥土被冲走，导致黄河两岸严重的水土流失，在山西省有些地区，折中水土流失几乎会掉了所有的土地，还迫使当地的农民迁移到其他地区去控制黄河水土流失是一项巨大的工程，很多人认为这项工作最好靠政府或是国际组织承担，你或许会赞同这样的观点，若真这样想的话，现在到了你重新考虑的时候了。 事实上，你才是阻止黄河水土流失最重要的人物，你知道你的五元钱的重要性吗？首先，你可以用五元钱买一棵树，而这棵树可以使泥土不流失，在肥沃的土地上，当地农民可以种庄稼陌生，农民会用他们种的庄稼赚到钱购买所需物品或服务，这有助于发展地区经济。 还是你不理解你得五元钱有如此大的作用吧？那么，看看下面的事实吧：自1997年期，一项植树计划已使内蒙古就成沙流变成了绿色家园，世界各地的人前来这里观赏这一伟大的成就，另外，这项规划的成功大大的改变了当地人民的生活，试想一下，这一切就是始于五元钱。 所以，下次当你的口袋里有五元钱时，仔细想想该怎么花，情记住，你可以用它买树，为了我们的祖国人民一及你自己创造绿色的未来。 所以，下次当你口袋里再有五元钱时，仔细想想该怎么花。请记住，你可以用它买树，为了我们的祖国，为人民以及你自己创造绿色的未来 Lesson 4 无线耳机
球团竖炉工国家职业标准 1.职业概况 1.1职业名称 球团竖炉工。 1.2职业定义 使用球团焙烧设备，对球团矿进行焙烧，以获得合格球团矿的人员。 1.3职业等级 本标准共设四个等级，分别为：初级（国家职业资格五级）、中级（国家职业资格四级）、高级（国家职业资格三级）、技师（国家职业资格二级）。 1.4职业环境条件 室内、外、高温、有毒有害。 1.5 职业能力特征 手指、手臂灵活，动作协调；学习能力、色觉和空间感强；无高温禁忌症。 1.6基本文化程度 高中毕业（或同等学历）。 1.7培训要求 1.7.1培训期限 全日制职业学校教育，根据其培养目标和教学计划确定。晋级培训期限：初级不少于400标准学时；中级不少于300标准学时；高级不少于200标准学时；技师不少于150标准学时。 1.7.2培训教师 培训初、中、高级的教师应具有本职业技师及以上职业资格证书或相关专业中级及以上专业技术职务任职资格；培训技师的教师应具有本职业技师资格证书2年以上或相关专业高级专业技术职务任职资格。 1.7.3培训场地设备 满足理论知识培训场地应具有可容纳20名以上学员，并配备投影仪、电视机及播放设备；满足实际操作培训用的焙烧设备、控制设备、取样工具及相关设备等。 1.8鉴定要求 1.8.1适用对象 从事或准备从事本职业的人员。 1.8.2申报条件 ——初级（具备以下条件之一者） （1）经本职业初级正规培训达到规定标准学时数，并取得结业证书。 （2）在本职业连续见习工作2年以上。 （3）在本职业学徒期满。 ——中级（具备以下条件之一者） （1）取得本职业初级职业资格证书后，连续从事本职业工作3年以上，经本职业中级正规培训达到规定标准学时数，并取得结业证书。 （2）取得本职业初级资格证书后，连续从事本职业5年以上。 （3）连续从事本职业7年以上。 （4）取得经劳动保障行政部门审核认定的、以中级技能为培养目标的中等以上职业学校本职业（专业）毕业证书。 ——高级（具备以下条件之一者） （1）取得本职业中级职业资格证书后，连续从事本职业工作4年以上，经本职业高级正规培训达到
玻璃生产工艺流程图 玻璃是如何生产出来的呢？这个问题对于专家来说可能很简单，但是对于普通的消费者来说可能还是有了解的兴趣的，今天，我们和中华包装瓶网的小编一起去简要的了解一下。玻璃的生产工艺包括：配料、熔制、成形、退火等工序。分别介绍如下： 1．配料，按照设计好的料方单，将各种原料称量后在一混料机内混合均匀。玻璃的主要原料有：石英砂、石灰石、长石、纯碱、硼酸等。 2．熔制，将配好的原料经过高温加热，形成均匀的无气泡的玻璃液。这是一个很复杂的物理、化学反应过程。玻璃的熔制在熔窑内进行。熔窑主要有两种类型：一种是坩埚窑，玻璃料盛在坩埚内，在坩埚外面加热。小的坩埚窑只放一个坩埚，大的可多到20个坩埚。坩埚窑是间隙式生产的，现在仅有光学玻璃和颜色玻璃采用坩埚窑生产。另一种是池窑，玻璃料在窑池内熔制，明火在玻璃液面上部加热。玻璃的熔制温度大多在1300~1600゜C。大多数用火焰加热，也有少量用电流加热的，称为电熔窑。现在，池窑都是连续生产的，小的池窑可以是几个米，大的可以大到400多米。 3．成形，是将熔制好的玻璃液转变成具有固定形状的固体制品。成形必须在一定温度范围内才能进行，这是一个冷却过程，玻璃首先由粘性液态转变为可塑态，再转变成脆性固态。成形方法可分为人工成形和机械成形两大类。 A．人工成形。又有（1）吹制，用一根镍铬合金吹管，挑一团玻璃在模具中边转边吹。主要用来成形玻璃泡、瓶、球（划眼镜片用）等。（2）拉制，在吹成小泡后，另一工人用顶盘粘住，二人边吹边拉主要用来制造玻璃管或棒。（3）压制，挑一团玻璃，用剪刀剪下使它掉入凹模中，再用凸模一压。主要用来成形杯、盘等。（4）自由成形，挑料后用钳子、剪刀、镊子等工具直接制成工艺品。 B．机械成形。因为人工成形劳动强度大，温度高，条件差，所以，除自由成形外，大部分已被机械成形所取代。机械成形除了压制、吹制、拉制外，还有（1）压延法，用来生产厚的平板玻璃、刻花玻璃、夹金属丝玻璃等。（2）浇铸法，生产光学玻璃。（3）离心浇铸法，用于制造大直径的玻璃管、器皿和大容量的反应锅。这是将玻璃熔体注入高速旋转的模子中，由于离心力使玻璃紧贴到模子壁上，旋转继续进行直到玻璃硬化为止。（4）烧结法，用于生产泡沫玻璃。它是在玻璃粉末中加入发泡剂，在有盖的金属模具中加热，玻璃在加热过程中形成很多闭口气泡这是一种很好的绝热、隔音材料。此外，平板玻璃的成形有垂直引上法、平拉法和浮法。浮法是让玻璃液流漂浮在熔融金属（锡）表面上形成平板玻璃的方法，其主要优点是玻璃质量高（平整、光洁），拉引速度快，产量大。 4．退火，玻璃在成形过成中经受了激烈的温度变化和形状变化，这种变化在玻璃中留下了热应力。这种热应力会降低玻璃制品的强度和热稳定性。如果直接冷却，很可能在冷却过程中或以后的存放、运输和使用过程中自行破裂（俗称玻
北师大版高中英语模块一单词表Unit 1 Learning to learn Questionnaire n. 问卷；调查表 matter n. 物质；原因；事件vi. 有关系；要紧partner n. 伙伴；合伙人；配偶 Warm-up lifestyle n. 生活方式 shepherd n. 牧羊人；牧师；指导者 peaceful adj. 和平的，爱好和平的；平静的relaxing adj. 令人轻松的推想 stressful adj. 紧张的；有压力的 suppose conj. 假使…结果会怎样vt. 假设；认为；Lesson 1 series n. 系列，连续；[电] 串联；丛书 TV series n. 电视连续剧 cartoon n. 卡通片，[电影] 动画片；连环漫画 talk show脱口秀；访谈节目 complain vi. Vt投诉；发牢骚；诉说 couch vi躺着n. 睡椅，长沙发 couch potato成天躺著或坐在沙发上看电视的人switch n. 开关；转换；鞭子vi. 转换；抽打 switch on接通，开启 switch off关掉；切断（电源） switch over切换转换交换 play n. 游戏；比赛；剧本 vt. 游戏；扮演；演奏；播放；同…比赛BBC(British Broadcasting Corporation) 英国广播公司portable adj. 手提的，便携式的；轻便的 remote adj. 遥远的；偏僻的；疏远的n. 远程remote control远程控制遥控器 workaholic工作狂专心工作的人拼命三郎paperwork n. 文书工作 alarm n. 警报，警告器；惊慌 alarm clock闹钟 go off离开；进行；变质；睡去爆炸动身 take up拿起；开始从事；占据(时间,地方) be filled with充满装满vt. 被……充满 urgent adj. 紧急的；急迫的 personal adj. 个人的；身体的；亲自的document文档文件公文midnight n. 午夜，adj. 半夜的；漆黑的 bored adj. 无聊的；无趣的；烦人的 Lesson 2 stress n. 压力；强调；紧张；重要性；重读 vt. 强调；使紧张；加压力于 studio n. 工作室制片厂画室 expert n. 专家；行家；能手adj. 熟练的； suffer vi. vt. 遭受；忍受 suffer from 忍受，遭受；患…病；受…之苦 pressure n. 压力；压迫，[物] 压强 social adj. 社会的，社交的；群居的 reduce vi. vt. 减少；降低；缩小； organize vi. 组织起来；成立组织 vt. 组织；使有系统化； diet饮食节食日常饮食 stand n. 站立；立场；看台；停止vi. 站立；位于；停滞vt. 使站立；忍受；抵抗 prefer vt. 更喜欢；宁愿；提出；提升 Lesson 3 volunteer n. 志愿者；志愿兵adj. 志愿的vt. vi. 自愿graduate毕业生毕业研究生vi. 毕业；渐变 minus prep. 减，减去 n. 负号，减号；不足；负数 basin 盆地流域洗脸盆 challenge n. 挑战；怀疑vt. 向…挑战 support n. 支持；支援，供养；支持者，支撑物 vt. 支持，支撑；扶持，；赡养，供养 dial刻度盘拨号拨 design n. 设计；图案vt. 设计；计划；构思advertisement n. 广告，宣传 presentation n. 描述，陈述；介绍；赠送 solve解决解答求解 Lesson 4 accountant n. 会计师；会计人员 tube n. 管；电子管；隧道；电视机 crowded adj. 拥挤的；塞满的 nearby prep. 在…附近adj. 附近的，邻近的adv. 在附近otherwise adv. 否则；另外；在其他方面 forecast n. 预测，预报vt. vi预报，预测；预示.
12㎡×2球团竖炉工艺介绍 一．配料工艺介绍： 1.配料料仓布局，膨润土（1#和2#仓）铁精粉（3#-7#仓）由东向西一字排列。 2.原料入仓方式，袋装膨润土使用小型电动吊车起吊至料仓上方，包装袋下部开口，膨润土直接装入料仓。吊车配备电子吊钩称，在起吊入仓时分别对每袋膨润土计量并记录，每班汇总数量上报厂部；铁精粉使用装载机车辆运输入仓。 3.原料计量方式，配料室每个料仓下料口配备圆盘给料机和电子计量皮带秤，按照配比调整出料量，并记录数值。 4.原料经过配料皮带机输送到烘干混合机。 二．烘干混合工艺介绍： 1.混合的目的，使不同种类原料水分、粒度、成分等指标充分混合，得到均一稳定的造球原料。 2.烘干的目的，原料进场水份高低不同，为稳定造球原料水分在（7.5±0.5%）区间，使用烘干炉煤气与空气混合燃烧产生高温烘干气体，控制调整混合料水分。 3.烘干混合后的原料经过烘干皮带机输送到造球室。 三．造球工艺介绍： 1.设备布局，1#，2#造球室分别对应1#，2#竖炉。1#，2#造球室各3个造球盘，每个造球盘上方对应混合料仓和给料皮带。 2.造球原理，铁精粉被水润湿在滚动过程中靠毛细引力、分子引力、摩擦力等作用形成一定粒度的生球，并使生球具有一定强度能够入炉焙烧。 3.生球团经过生球皮带机输送到辊式筛分机。 四．辊式筛分机介绍： 1.筛分原理，通过调整相临圆辊之间的距离，把整个筛分机辊面分成Ф＜9mm，9-16mm和＞16mm三个区域。生球经过筛面时不同直径的生球被筛分三级，Ф9-16mm粒级入炉焙烧，Ф＜9mm和＞16mm粒级不合格生球由返料皮带机输送返回造球室。（粒级区间可按实际生产调整） 2.合格生球经过生球皮带机输送到竖炉布料。 五．竖炉焙烧工艺介绍： 1.布料工艺，合格生球通过往复梭式布料车均匀铺在“人”字型烘干床上。 2.焙烧工艺，生球由炉顶向下经过烘干→预热→焙烧→均热→冷却过程。 3.红热球团由振动卸料机和链板机输送到带式冷却机。 六．成品冷却系统介绍： 1.带式冷却机，台车底部为通风篦板，按冷却需求开启4台鼓风机。带冷机排矿温度≤150℃。 2.成品球团经过成品皮带机输送至高炉或汽运落地库存。 七．脱硫系统介绍： 1.脱硫原理，制备消石灰CaO+H 2O→Ca(OH) 2 烟气脱硫SO 2+Ca(OH) 2 →CaSO 3 +H 2 O 2.系统流程,烟气→电除尘→风机→石灰浆液逆流喷淋→浆液真空过滤→脱硫石膏排出。