Transkription---Das duale System in Deutschland

a r X i v :n l i n /0612038v 1 [n l i n .S I ] 16 D e c 2006Controlling pulse propagation in optical fibers through nonlinearity and dispersionmanagementRajneesh Atre 1,2,∗and Prasanta K.Panigrahi 1,†1Physical Research Laboratory,Navrangpura,Ahmedabad 380009,India 2School of Physics,University of Hyderabad,Hyderabad-500046,India(Dated:February 8,2008)In case of the nonlinear Schr¨o dinger equation with designed group velocity dispersion,variable nonlinearity and gain/loss;we analytically demonstrate the phenomenon of chirp reversal crucial for pulse reproduction.Two different scenarios are exhibited,where the pulses experience identical dis-persion profiles,but show entirely different propagation behavior.Exact expressions for dynamical quasi-solitons and soliton bound-states relevant for fiber communication are also exhibited.PACS numbers:42.81.Dp,05.45.Yv,42.65.TgNonlinear Schr¨o dinger equation (NLSE)is known to govern the pulse dynamics in nonlinear optical fibers [1].In recent years,the study of nonlinear fiber optics,deal-ing with optical solitons,has attracted considerable at-tention since it has an important role in the development of several technologies of the 21st century [2].NLSE with distributed coefficients such as,group velocity dispersion (GVD),distributed nonlinearity and gain/loss,is being studied extensively in order to determine the effect of various distributed parameters on the pulse profile.In the realistic situation in a fiber,there arises non-uniformity due to variation in the lattice parameters of the fiber medium,as a result of which the distance be-tween two neighboring atoms is not constant through-out the fiber.It may also arise due to the variation of the fiber geometry e.g.,diameter fluctuation.These non-uniformities influence effects such as,loss (or gain),phase modulation,etc,which can be modeled by making corre-sponding parameters space dependent.From a practical point of view,tailoring of various fiber parameters may lead to effective control of the pulse.This has been one of the prime motivation of a number of authors to analyze NLSE in a distributed scenario.Dispersion management (DM)has emerged as an im-portant technology to control and manipulate the light pulses in optical fibers [2,3].Pulse compression has been demonstrated with appropriately designed GVD and nonlinearity in the presence of chirping [4,5,6],as also through soliton effects [7].Adiabatic soliton com-pression,through the decrease of dispersion along the length of the fiber has been shown to provide good pulse quality [8].The possibility of amplification of soliton pulses using a rapidly increasing distributed amplifica-tion with scale lengths comparable to the characteristic dispersion length has been reported [9].It has been nu-merically shown that,in the case where the gain due to2 Schr¨o dinger eigenvalue problem.This allows one to ana-lytically treat a variety of distributed scenarios,a few ofwhich we explicate in the text.In the context of Bose-Einstein condensates the procedure to deal with variablecoefficient NLSE in the absence of GVD has been carriedout recently by the present authors[16].GVD leads to afundamentally new control parameter in the present casedealing with opticalfibers.For example,a subtle inter-play of GVD and nonlinearity leads to a soliton bound-state as will be seen below.The effect of GVD,alternat-ing between normal and anomalous dispersion,on pulseprofile is also discussed.For the purpose of analytic demonstration of chirp re-versal we start with a NLSE model with variable GVD,nonlinearity and loss/gain[14]:i∂z q(z,t)+d e(z)2∂tt u(z′,t)+˜γ(z′)|u|2u(z′,t)=0,(2)where z′= z0dz′′a2(z′′).Keeping in mind,pre-chirping and self-similar natureof the pulse we make use of the following ansatz,u(z′,t)=∂z′+K0τ∂ν2∂2ν(z′,τ)2ν+iK0νp,and K1=C z′+C2d e∂z′+d e p2∂τ2+˜γ(z′)p|ν|2ν(z′,τ)=K1τ2∂z′′+1∂τ2+˜γ(z′′)|ν|2ν(z′,τ)=K1τ2A(z′′)F[A(z′′){τ−Λ(z′′)}]e iΦ(z′′,τ),(8)whereΦ(z′′,τ)=a1(z′′)+b(z′′)τ−12 z′′0A2(z)dz,Λ(z′′)=z′′0v(z)dz,which satisfies the following equation:dΛA0.(14)The twelve Jacobian elliptic functions satisfy aboveequation.These functions interpolate between thetrigonometric and hyperbolic functions in the limitingcases[17].Bright soliton solutions of the typeν(z′′,τ)=312345z1.51 0.500.51C h i r pFIG.1:The figure depicting variation of chirp parameters with z .The red curve shows the launching chirp and the blue curve shows the same in combination with the dynamical chirp.pulse profile.However,the pulse retains its fundamental NLSE soliton character in the scaled variable z ′′.Below,we examine the formation of bright quasi-soliton like excitations,exhibiting chirp reversal phe-nomenon.This is accomplished by appropriate tailoring of GVD and pre-chirping of the launching -bining Eq.(5)and constraint d e p =1,yield the following expressions for the tailored dispersion and the chirping parameter,C =d ′ed z ′2−d d eδsinh(δz ′),with δ= K 1+C 2(0) 1/2.(16)From above dispersion profile we compute launched chirp parameter C (z ′)and plot it together with the dy-namical chirp in Fig. 1.From Eqs.(5)and (16)it is clear that launched chirp profile changes sign at z (z ′c )=(1/δ)tanh −1[−C (0)/δ].The expression for traveling quasi-soliton,propagating with velocity v (z ′′)=A 0cos (K 0z ′′),readsq (z,t )=a (z )p (z ′)sech(K 1z ′′)sech [sech(K 1z ′′){τ−Λ(z ′′)}]×exp i C (z ′)t 2+Φ(z ′′,τ).(18)It is interesting to observe that,compared with theprevious case pulse broadening is significantly reduced for the same parameter values.Soliton bound-states.–Starting from Eq.(1)without tai-loring the dispersion profile,we proceed to obtain self-similar solutions assuming the ansatz solution of the type:q (z,t )=4−10−5510−10−55100.10.20.30.40.50.60.70.80.91FIG.4:Soliton bound-state in a medium with two dispersion regimes.FIG.5:Multiple soliton bound-state with oscillatory gain/loss.The parameters appearing in the Eq.(19)can be straightforwardly evaluated from the Eqns.(11),(12),(13)and soliton profile can be obtained from Eq.(14).Below,we explicate some examples of spatial bound-states of solitons,arising from interplay of GVD,non-linearity and gain/loss.Below,Fig.4depicts a two-soliton bound-state.This arises in a medium,where both anomalous and normal dispersion regimes are smoothly connected.In the presence of periodic gain/loss one ob-serves modulation in the bound-state profile as is shown in Fig.5.In conclusion,we have obtained exact soliton solutions exhibiting chirp-reversal,while retaining their original profile,crucial for pulse recovery in fiber optics.Two different soliton sectors differing in propagation behavior,but with identical dispersion profiles,are analytically ex-hibited.We have outlined a general formalism for obtain-ing self-similar solutions of nonlinear Schr¨o dinger equa-tion,in the presence of distributed coefficients,from which earlier scenarios follow as special cases [19].It is shown that,this nonlinear system,involving pulse prop-agation with group velocity dispersion (GVD),variable nonlinearity,variable gain,exactly decouples into ellip-tic function equation and a Schr¨o dinger eigenvalue prob-lem.This opens up a number of possibilities to take into account a wide class of distributed scenarios,in close conformity with the experimentally achievable situations.This incorporates a number of special cases dealt ear-lier,in the context of pulse compression.We find that,apart from compression,one can achieve control over the pulse velocity,pulse profile,through interplay of group velocity dispersion,nonlinearity,gain/loss.Formation of soliton bound-states in a medium with GVD alternating between normal and anomalous dispersion,is discussed.In the presence of oscillatory gain/loss profile,we find multiple bound state structure.We acknowledge many useful discussions with Prof.G.S.Agarwal.[1]G.P.Agrawal,Nonlinear Fiber Optics (Academic Press,Inc.,San Diego,CA,2001).[2]A.Hasegawa and 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Table of Contents（目录）How to Use This Guide （如何使用本指南）Chapter 1 Introduction to System Troubleshooting（系统故障检修介绍）1.1 Get the Facts（获取真相）1.2 Check Simple Things First（从简单的方面检查开始）1.3 Compare System Performance to Established Benchmarks（从比较系统性能到建立基准）1.4 Identify Possible Causes（确定可能原因）1.5 Use a Systematic Troubleshooting Approach（使用一种系统内部的故障检修方法）1.6 Getting Help（获取帮助）1.7 Troubleshooting References（故障检修参考书目）Chapter 2 Troubleshooting an LC System （检修一个液相色谱系统）2.1 Initial Survey of System Problems（系统问题的最初调查）2.2 Isolating System Problems（分离系统问题）2.2.1 System Pressure（系统压力）2.2.2 Baseline Noise（基线噪音）2.2.3 Changes in Chromatographic Resolution or Results（色谱分离度或结果的改变）Chapter 3 Troubleshooting System Components（检修系统构件）3.1 Pump Troubleshooting（色谱泵检修）3.1.1 Pump Troubleshooting T able（色谱泵检修表格）3.1.2 Isolating a Defective Pump Head (Modified Ramp Test)（分离一个受损泵头）3.2 Manual Injector Troubleshooting （进样器检修手册）3.3 Autoinjector Troubleshooting （自动进样器检修）3.4 Column Troubleshooting （色谱柱检修）3.5 Detector Troubleshooting（检测器检修）3.6 Data-Handling Device Troubleshooting（数据处理装置检修）Chapter 4 Good Chromatography/ Operating Practices（良好的色谱操作规范）4.1 Mobile Phase Preparation and Use（流动相制备和使用）4.1.1 Mobile Phase Preparation （流动相制备）4.1.2 Solvent Degassing（溶剂脱气）4.1.3 Solvent Use（溶剂使用）4.1.4 Solvent Changeover Practices（溶剂转换规范）4.2 System Plumbing （泵输送系统）4.2.1 Tubing Connection Practices （管道连接规范）4.2.2 Cutting Tubing（切割管路）4.3 Chromatographic Performance Tests（色谱性能测试）4.3.1 Measuring Resolution（测量分离度）4.3.2 Measuring Capacity Factor (k') （测量容量因子k'）4.3.3 Measuring Selectivity（测量选择性）4.3.4 Measuring Column Efficiency (N) （测量柱效（N））4.4 Measuring System Bandspreading（测量系统拖尾因子）Appendix A （附录A）Reference Information（参考信息）A.1 Solvent Properties（溶剂属性）A.1.1 Solvent Properties Table （溶剂属性表）A.1.2 Using Miscibility Numbers (M-Numbers) （使用可混和性编号（M-编号））A.2 Refractive Index of Common Solvents（常见溶剂的折射指标）.A.3 Solvent UV Cutoffs （溶剂紫外离群值截断点）A.4 Wavelength Selection for Chromophore Detection（色谱检测器的波长选择）A.5 Column Backpressure （柱后压）Waters公司液相色谱资料系列－ⅡHPLC Troubleshooting Guide （HPLC故障检修指南）本资料为英文版本，文件大小为836KB，PDF格式，全书共68页，编排为目录、主题内容和附录三部分，带书签和搜索功能，由美国Waters公司专家Uwe D. Neue编写，内容包括52个主题。

形容多个传感器之间可以相互独立的英文单词Title: Describing Sensors that Can Operate IndependentlyIntroductionIn the world of technology and IoT (Internet of Things), sensors play a crucial role in collecting and transmitting data for various applications. These sensors can operate independently, performing their designated functions without the need for constant human intervention. In this article, we will explore and describe various terms used to depict sensors that can function autonomously.1. AutonomousAutonomous sensors refer to devices that can operate or function independently without the need for external control. These sensors are self-sufficient in terms of power supply, data collection, processing, and transmission. The autonomy of these sensors allows them to perform their tasks efficiently without relying on a central system or operator.2. StandaloneStandalone sensors are those that are self-contained and do not rely on other devices for operation. These sensors aredesigned to function independently, collecting and processing data on their own. Standalone sensors are commonly used in applications where mobility, flexibility, or remote operation is required.3. DecentralizedDecentralized sensors operate independently and can communicate with each other without the need for a centralized control system. This decentralized approach allows sensors to collaborate and exchange information to achieve a common goal. Decentralized sensors are often used in distributed sensor networks for monitoring and control applications.4. Self-organizingSelf-organizing sensors have the ability to form networks and coordinate their activities without human intervention. These sensors can establish connections, assign roles, and adapt to changing environments autonomously. Self-organizing sensors are commonly used in dynamic and unpredictable settings where traditional communication methods may not be feasible.5. Ad-hocAd-hoc sensors are capable of forming temporary networks on the fly, without the need for pre-established infrastructure. These sensors can spontaneously connect with each other to share data and collaborate on tasks. Ad-hoc sensors are often used in scenarios where quick deployment and flexibility are essential.ConclusionIn conclusion, sensors that can operate independently play a vital role in various applications, from smart homes and industries to healthcare and environmental monitoring. Understanding and describing the characteristics of these sensors, such as autonomy, standalone capability, decentralization, self-organization, and ad-hoc networking, are essential for designing and implementing efficient sensor systems. By harnessing the power of independent sensors, we can create smarter, more responsive, and interconnected systems for a wide range of practical applications.。

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第28卷（2010）第3期内燃机学报Transactions of CSICEVol.28（2010）No.3文章编号：1000-0909（2010）03-0265-0428-041柴油机双回路冷却系统的设计和试验*傅寿宇1，郭新民1，张坤1，牛化武2，陈卫正1（1.山东农业大学机械与电子工程学院，山东泰安271018；2.泰山职业技术学院机电系，山东泰安271000）摘要：针对当前汽车运输中发动机普遍存在的冬季预热缓慢和夏季过热现象，设计了双回路智能冷却系统。

该系统由单片机根据冷却液温度控制冷却风扇和电动水泵的运转，结合两个节温器的开闭，可分别对缸体和缸盖的温度进行自动控制。

将该双回路冷却系统在CA498柴油机上进行了试验。

结果证明，该冷却系统可以将发动机暖机阶段的预热时间减少，油耗降低；可避免过热现象的发生；各工况下HC的排放率也得到了降低。

关键词：柴油机；冷却系统；双回路；控制装置中图分类号：TK424.2文献标志码：ADesign and Study of the Dual Circulation Cooling System in Diesel EngineFU Shou-yu1，GUO Xin-min1，ZHANG Kun1，NIU Hua-wu2，CHEN Wei-zheng1（1.Mechanical and Electrical Engineering College，Shandong Agricultural University，Tai’an271018，China；2.Mechanical and Electrical Engineering Department，Taishan College of Vocational and Technical，Tai’an271000，China）Abstract：To solve the problem of over-heating in summer and slow warm-up in winter in automobiles，adual-loop cooling system is designed，in which a microcontroller controls the rotating speeds of both cool-ing fan and water pump according to water temperature.The temperatures of cylinder head and block wereregulated through double thermostats.Testing on CA498diesel engine showed that the cooling systemcould effectively shorten the warming time，reduce fuel consumption in warm-up period，avoid over-heat-ing problem，and reduce HC emission under different operating conditions.Keywords：Diesel engine；Cooling system；Dual loop；Control device引言汽车发动机在工作中，由于受到环境温度变化，使用维护状况、运行、负荷等因素的综合影响，以及冷却水泵只能随发动机的运转一起运行的局限性，易导致发动机出现预热缓慢、排出大量的蓝烟、过热等现象。