4T2_ Phase Diagrams and Microstructure of HT Alloys_2015

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宏观傅里叶叠层技术远距离成像实验研究

航天返回与遥感第44卷第6期38 SPACECRAFT RECOVERY & REMOTE SENSING2023年12月宏观傅里叶叠层技术远距离成像实验研究田芷铭赵明王森李剑（大连海事大学，大连116026）摘要傅里叶叠层是一新型的宽视场高分辨成像技术，但是其在宏观成像领域的应用中，成像模型在米级成像距离下通常仅有2 cm左右的成像视场，难以满足使用要求。

为了提高宏观傅里叶叠层技术的成像距离和视场，文章开展了远距离宏观反射式傅里叶叠层成像模型的理论研究，提出了一种新的宏观傅里叶叠层成像模型，该模型使用发散光束照明，通过球面波移位对目标傅里叶谱进行扫描重建高分辨率目标图像；此外，还分析了宏观相干成像机理和傅里叶成像模型近似条件，由此推导出模型的近似范围，为模型推广提供了理论基础；最后，利用搭建的实验系统对10 m外目标成像，使目标分辨率从1.4 mm提升到0.35 mm，分辨率提升4倍以上，验证了模型具有通过合成孔径技术提升目标成像分辨率的能力。

关键词宏观成像傅里叶叠层成像模型远距离成像超分辨技术傅里叶叠层实验中图分类号: TP391.41文献标志码: A 文章编号: 1009-8518(2023)06-0038-07 DOI: 10.3969/j.issn.1009-8518.2023.06.004Experimental Research on Long-Range Imaging Using MacroscopicFourier Ptychographic TechnologyTIAN Zhiming ZHAO Ming WANG Sen LI Jian（Dalian Maritime University, Dalian 116026, China）Abstract Fourier ptychography is a promising high-resolution imaging technique that has been gradually applied in the field of macroscopic imaging. However, its imaging model typically provides a limited field-of-view of around 2 cm at meter-level imaging distances, which often falls short of practical requirements. To enhance the imaging distance and field-of-view of macroscopic Fourier ptychography, this article conducted theoretical research on the long-distance macro reflection Fourier stack imaging model. The proposed model utilizes diverging light beams for illumination, scans the target Fourier spectrum using spherical wavefront shifting, and reconstructs high-resolution target images. The article analyzes the mechanism of macroscopic coherent imaging and the approximation conditions of the Fourier imaging model, deriving the approximate range of the model and establishing a theoretical foundation for its extension. Finally, the built experimental system was used to image a target 10 meters away, increasing the target resolution from 1.4 mm to 0.35 mm, a resolution increase of more than 4 times, verifying the model’s capability to improve target imaging resolution through the synthetic aperture technology.收稿日期：2023-06-20引用格式：田芷铭, 赵明, 王森, 等. 宏观傅里叶叠层技术远距离成像实验研究[J]. 航天返回与遥感, 2023, 44(6): 38-44.TIAN Zhiming, ZHAO Ming, WANG Sen, et al. Experimental Research on Long-Range Imaging Using Macroscopic Fourier Ptychographic Technology[J]. Spacecraft Recovery & Remote Sensing, 2023, 44(6): 38-44. (in Chinese)第6期田芷铭等: 宏观傅里叶叠层技术远距离成像实验研究 39Keywords macroscopic imaging; Fourier ptychographic model; long-range imaging; super-resolution technology; Fourier ptychographic experiment0 引言目前，在监视、遥感等领域，高分辨率成像问题面临着重要挑战。

Resonant modes and laser spectrum of microdisk lasers

Resonant modes and laser spectrum of microdisk lasersN. C. Frateschi and A. F. J. LeviDepartment of Electrical EngineeringUniversity of Southern CaliforniaLos Angeles, California 90089-1111ABSTRACTA theory for quantitative analysis of microdisk laser emission spectra is presented. Conformal mapping is used to determine the radial and azymuthal eigenvalues and eigenvectors corresponding to leaky optical modes in the disk. The results are compared with experimental data obtained from a 0.8mm radius InGaAs/InGaAsP quantum well microdisk laser.New semiconductor microdisk1,2 and microcylinder3 resonant cavities have been studied with measured lasing emission wavelength at λ=1550nm,4λ=980nm,3 and λ=510nm.5 Position in a cylinder is specified by natural axial coordinate, z, radial coordinate, r, and azymuthal angle, q. Isolated short cylinders are disks of thickness L. The design and optimization of a semiconductor microdisk laser is critically dependent on the Q of resonant optical modes as well as the spectral and spatial overlap of these modes with the active medium.Microdisk lasers typically consist of a quantum well active region which can exhibit optical gain at, for example, λ=1550nm. For such devices disk radius 0.5µm<R<10µm and thickness 0.05µm<L<0.3µm. Because of high optical confinement due to the air/semiconductor interface, in essence device models involve solving for the optical field ψ(r,θ) in the 2-dimensional transverse direction for a medium with refractive index n=neff. The Helmholtz equation for optical field is separable in r and θ so that ψ(r,θ)=R(r)e iZθ and we may writer2ddr22R r()+r ddrR r()−(k2r2+Z2)R r()=0andd2dθ2Θ(θ)−Z2Θ(θ)=0where k=neffω/c. Z is, in general, a complex constant. Two polarizations can be studied with the TE (TM) mode of the slab waveguide having the magnetic (electric) field in the ˆz directionE z (r,θ) (Hz(r,θ)) with neff=neffTE(TM).One approach to simplify the problem is to assume that optical resonances may beapproximated by the whispering gallery modes (WGM) which are obtained by applying theboundary condition ψin (R,θ)=0. In this situation ψin(r,θ)=AMJM(rneffωM,N/c)e iMθwhere JMare Bessel functions of integer order Z M≡=±±±0123,,,,... and A M is a normalization constant.The boundary condition results in resonance frequencies ωM,N`=xMN c/neffR where xMN is the N thzero of J M (r ) and N =1 for WGMs. One may show that the instantaneous Poyting vector is of the formk M =k θ(r )cos 2(M θ)ˆθ+k r (r )sin(2M θ)ˆr with propagation in the ˆθdirection (clockwise or counterclockwise depending on the sign of M )and 2M symmetrical mirror-reflections with respect to the radial direction. The time average energy flux is given by S ∝c µωM ˆθ so that no optical energy escapes the disk in the radial direction.A physically more reasonable solution is obtained by assuming a complex number Z =M +i αR to be the eigenvalue for the Helmholtz equation. This allows ψ to have exponential decay in the azymuthal direction and Bessel type functions of "complex order" in the radial direction that lead to radial energy flux. Nevertheless, for high order M 's and N =1 we anticipate a small radial flux of energy so α is very small. In this limit WGM behavior is a good approximation. However, since in these modes no energy leaves the cavity, radiation losses may not be calculated directly. For small disks, M is small since the resonance wavelengths can not besmaller than the wavelength in the material (x M N ≤2πRn eff 2/λ). Therefore, in this situation,physically meaningful solutions depart considerably from the WGM picture. This paper presents results of using conformal mapping to obtain exact solutions for the resonant modes and respective losses in small optically transparent disks for which low M values are important.The first step in the exact calculation is to follow the approach used by Heiblum and Harris to calculate loss in curved optical waveguides.6 In this work a conformal transformation u +iv =f (r ,θ)=R ln[re i θ/R ] is applied to the 2-dimensioned Helmholtz equation. The problem istransformed into an asymmetric slab waveguide in the ˆvdirection with a varying index of refraction profile n (u )=n eff e u /R for r ≤R and n (u )=e u /R for r >R as illustrated in Fig. 1.Modes propagate according to f (u ,v )=U (u )e i (β+i α). For the microdisk resonator Z =M +i αR gives Ψ(r ,θ)=F (r )e iM θe −αθ in real space and Ω(u ,v )=H (u )e iM /R θe −αθ/R in the transformedspace. That is, a wave propagating in the ˆvdirection with a known propagation constantkv=M/R with M integer to guarantee a stationary solution in the ˆθdirection and a propagation loss α. In the ˆu directiond2H(u) du2+ω2c2η2(u)H(u)=0where plane waves in each infinitesimal slice δu propagate in the ±ˆu direction through an index of refractionη(u)=n2(u)−(cω(M/R+iα))2.These waves change phase by δφ=(ω/c)η(u)δu in the medium and are reflected at the discontinuities of h(u). For α<<M/R reflections occur at the roots of n(u)=(c/ω)M/R,u 1=R ln[(c/ω)M/Rneff]for u<0 and u2=R ln[(c/ω)M/R] for u>0 and at the physicalinterface at u0=0. Fig. 1 shows these reflection points for a given M, note that u1and u2aremetal-type reflections while uis a dielectric-type reflection. A stationary solution in u willrequire a round trip phase change N2πN=1,2,3,... between u1and u. For u1 to existM<Mmax =2πRneff/λmust be satisfied. At uthe phase change depends on phase responsefrom the combined dielectric- and metal-type reflections that occur at u0, the segment Γ, and u2.Also it depends on the polarization since for the TM (TE) slab modes ∇u H(u)(∇uH(u)ε) iscontinuous. If these reflections are in phase, high reflectivity results and a quasi-confined stationary mode exists. The requirement on round-trip phase and constructive reflection at theu 0−Γ−u2mirror combination result in two equations involving α and ω for a given M and N.A quasi-confined stationary mode M with round-trip phase N2π resonates with frequency ωM,N,loss αM,N and a very fast optical feedback time on the scale of 2π/ωM,N. We also note that whenu 2 doesn't exist (M<Mmin=2πR/λ) stationary (but not quasi-confined) states are allowed sincelight leaving the disk only sees a low reflectivity dielectric interface in a situation physically analogous to below the critical angle φCincidence. We expect, therefore, spectral lines with cavityQ=M/αM,NR to occur within the range of non quasi-confined spontaneous emission.Fig. 2 shows measured spectra for a microdisk with R =0.8µm and L =0.18µm . The medium has an average refractive index n =3.456+0.333(h ω−0.74eV ).4 Emission peaks at λ5,1=1542nm and λ4,1=1690nm are observed in a spontaneous emission background ranging from λ=1300nm to λ=1800nm . To calculate the spectra for this structure we fit the calculatedeffective index dispersion n eff =n eff TE =1.494+1.427h ω. We have neglected TM emission sincen eff TM is too small to allow resonances within the spontaneous emission range. For this n eff and the wavelength range of interest, 3<M <9. Fig. 3 shows the calculated spectral lines for this disk where modes with Q >0.2 were considered. The cavity Q increases exponentially with M and we observe that it reduces rapidly with N. The modes (5,1) and (4,1) match very well the measured resonances shown in Fig. 2 where a combination of higher Q and greater overlap with the spontaneous emission lead to the dominating mode at λ5,1=1540nm . The highest Q mode in this range (6,1) is not seen in the spectra because, unlike our model, the semiconductor is strongly absorbing at this wavelength. M =7,8,9 with higher Q are not depicted because for these resonances λ<1300nm .In summary, conformal mapping is used to determine the radial and azymuthal eigenvalues and eigenvectors of leaky optical modes present in dielectric microdisks. Remarkably, our model,which describes resonances in an optically transparent medium, appears to apply equally well to semiconductor microdisk lasers. Agreement with experimental results is very good even though gain and loss vary considerably over the wavelength range of spontaneous emission in the device.This work is supported in part by the Joint Services Electronics Program under contract #F49620-94-0022.REFERENCES[1]S. L. McCall, A. F. J. Levi, R. E. Slusher, S. J. Pearton, and R. A. Logan Appl. Phys. Lett. 60, 289 (1992).[2] A. F. J. Levi, R. E. Slusher, S. L. McCall, T. Tanbun-Ek, D. L. Coblentz and S. J. Pearton, Electron. Lett. 28, 1010 (1992).[3] A. F. J. Levi, R. E. Slusher, S. L. McCall, S. J. Pearton, and W. S. Hobson, Appl. Phys. Lett. 62, 2021 (1993).[4] A. F. J. Levi, S. L. McCall, S. J. Pearton, and R. A. Logan, Electron. Lett. 29, 1666 (1993).[5]M. Hovinen, J. Ding, A. V. Nurmikko, D.C. Grillo, J. Han, L. He, and R. L. Gunshor, Appl. Phys. Lett. 63, 3128 (1993).[6]M. Heiblum and J. H. Harris, IEEE J. Quantum Electron. QE-11, 75 (1975).urn 2(u )ω2c 2max2min22Figure 1 - Index of refraction profile for the slab waveguide in the transformed space (u ,v ). The reflection points (u 0,u 1,u 2) are shown for a mode with M Min ≤M ≤M Max .180017001600150014001300P ex =1.5m WP ex =1.0m WP ex =0.6m WWav eleng th λ, n mFigure 2 - Room temperature photoluminescence spectra of R =0.8µm radius microdisk laser.An AlGaAs/GaAs laser diode provides λ=0.85µm wavelength power for the optical pump. P ex is the incident excitation power.40.11101001000180017001600150014001300C a v i t yQ Wa velen gth λ, n mFigure 3 - Calculated spectral lines with respective cavity Q for the resonant modes in the R =0.8µm radius microdisklaser of Fig. 2. The broken line represents the experimentally observed spontaneous emission.。

CALPHAD软件介绍

Abstract
The phase-ﬁeld method has become an important and extremely versatile technique for simulating microstructure evolution at the mesoscale. Thanks to the diffuse-interface approach, it allows us to study the evolution of arbitrary complex grain morphologies without any presumption on their shape or mutual distribution. It is also straightforward to account for different thermodynamic driving forces for microstructure evolution, such as bulk and interfacial energy, elastic energy and electric or magnetic energy, and the effect of different transport processes, such as mass diffusion, heat conduction and convection. The purpose of the paper is to give an introduction to the phase-ﬁeld modeling technique. The concept of diffuse interfaces, the phase-ﬁeld variables, the thermodynamic driving force for microstructure evolution and the kinetic phase-ﬁeld equations are introduced. Furthermore, common techniques for parameter determination and numerical solution of the equations are discussed. To show the variety in phase-ﬁeld models, different model formulations are exploited, depending on which is most common or most illustrative. c 2007 Elsevier Ltd. All rights reserved.

基于石墨烯超表面的效率可调太赫兹聚焦透镜

DOI: 10.12086/oee.2021.200319基于石墨烯超表面的效率可调太赫兹聚焦透镜王俊瑶，樊俊鹏，舒好，刘畅，程用志*武汉科技大学信息科学与工程学院，湖北武汉 430081摘要：本文提出了一种基于石墨烯超表面的效率可调太赫兹聚焦透镜。

该超表面单元结构由两层对称的圆形镂空石墨烯和中间介质层组成，其中镂空圆形中间由长方形石墨烯片连接。

该结构可实现偏振转换，入射到超表面的圆偏振波将以其正交的形式出射，如左旋圆到右旋圆偏振转换。

利用几何相位原理，通过旋转长方形条的方向，透射波会携带额外的附加相位并能满足2π范围内覆盖。

合适地排列石墨烯超表面的单元结构，以实现太赫兹聚焦透镜。

仿真结果表明：通过改变石墨烯的费米能级，可以对超表面圆偏振转换幅度进行调节，进而超透镜的聚焦效率也可以动态调节。

因此，这种基于石墨烯超表面的效率可调聚焦透镜不用改变单元结构的尺寸，只需通过改变费米能级便可实现，可以广泛地应用到能量收集、成像等太赫兹应用领域。

关键词：超表面；聚焦透镜；石墨烯；太赫兹中图分类号：TH74；TQ127.11 文献标志码：A王俊瑶，樊俊鹏，舒好，等. 基于石墨烯超表面的效率可调太赫兹聚焦透镜[J]. 光电工程，2021，48(4): 200319Wang J Y , Fan J P , Shu H, et al. Efficiency-tunable terahertz focusing lens based on graphene metasurface[J]. Opto-Electron Eng , 2021, 48(4): 200319Efficiency-tunable terahertz focusing lens based on graphene metasurfaceWang Junyao, Fan Junpeng, Shu Hao, Liu Chang, Cheng Yongzhi *School of Information Science and Engineering, Wuhan University of Science and Technology, Wuhan, Hubei 430081, China Abstract: This paper proposes an efficiency-tunable terahertz focusing lens based on the graphene metasurface. The unit cell is composed of two symmetrical circular graphene hollows and an intermediate dielectric layer, wherein the hollow circular middle is connected by a rectangular graphene sheet. This structure can realize polarization conversion, for example, when an incidence with left-hand circular polarization emitted on the metasurface the po-larization of the transmitted light is right-hand circular polarization. According to the principle of geometric phase, by rotating the direction of the rectangular bar, the transmitted wave will carry an additional phase and can cover the range of 2π. An THz focusing lens can be realized by properly arranging the unit structure of the graphene metasurface. The simulation results show that the conversion amplitude of circular polarized light can be adjusted by changing the Fermi level of graphene, and the focusing efficiency of the metalens can also be dynamically adjusted.LCPRCP(cross-polarization)xy zV g——————————————————收稿日期：2020-08-27；收到修改稿日期：2020-10-26基金项目：湖北省教育厅科技研究计划重点项目(D2*******)；武汉科技大学研究生创新基金项目(JCX201959)；大学生创新基金项目资助课题(20ZA083)作者简介：王俊瑶(2000-)，女，主要从事电子科学与技术专业。

Journal of the Electrochemical Society 152(4) A653-A657 (200

Preparation and Characterization of Thin Film Li4Ti5O12Electrodes by Magnetron SputteringC.-L.Wang,a,b Y.C.Liao,a,c,z F.C.Hsu,a,b N.H.Tai,b and M.K.Wu a,c,da Materials Science Center,b Department of Materials Science and Engineering,andc Department ofPhysics,National Tsing Hua University,Hsinchu,Taiwand Institute of Physics,Academia Sinica,Nankang,Taipei,TaiwanThis paper reports that spinel-phase Li4Ti5O12thinﬁlms were successfully grown by radio frequency͑rf͒magnetron sputtering on an Au/Ti/SiO2/Si substrate.In this process,the buffer layer of gold serves as a template for the texture growth of Li4Ti5O12ﬁlm. The growth temperature affects the microstructure and electrochemical characteristics of the depositedﬁlms.In our study,the spinel phase of Li4Ti5O12appears at deposition temperatures above500°C.The redox peaks in the cyclic voltammetry of the Li/Li4Ti5O12cell approach the typical value of1.55V as raising the deposition temperature.Moreover,the inﬂuences of the surface morphology of theﬁlm on the capacity were studied.They show that a columnar structure with high porosity was obtained in theﬁlm deposited above650°C.The columnar grains with good crystallinity of the deposited Li4Ti5O12enhance the capacity of the electrode.In this work,the capacity of53␮Ah/cm2␮m can be attained for theﬁlm with a thickness of230nm deposited at700°C.This study sheds light on the realization of a solid-state thinﬁlm battery and provides a possible solution of electrical power for a mobile integrated circuit chip.©2005The Electrochemical Society.͓DOI:10.1149/1.1861193͔All rights reserved.Manuscript submitted May17,2004;revised manuscript received September25,2004.Available electronically February10,2005.Solid-state thin-ﬁlm rechargeable batteries have great advantages over other types of batteries due to theirﬂexibility,safety,and min-iaturization.There are many potential applications,such as smart cards,complementary metal oxide semiconductor͑CMOS͒-based integrated circuits,and microelectromechanical system͑MEMS͒de-vices.Lithium-transition-metal-oxide thinﬁlms have long been recognized as good candidates for battery electrode materials. For example,layered-phase LiCoO2,1LiNiO2,2and spinel-phase LiMn2O43with high voltage and stability were successfully used as the positive electrode in lithium ion batteries.Thackeray et al.4pro-posed that the ionic conductor Li4Ti5O12can also be a good elec-trode material for rechargeable lithium ion batteries.This material can be used as the negative electrode in the cell combined with other high voltage materials,such as LiCoO2and LiMn2O4.5,6The theo-retical capacity of Li4Ti5O12is175mAh/g͑60␮Ah/cm2␮m͒ac-cording to the following reaction suggested by Ohzuku et al.7͑Li͒8a͑Li1/3,Ti5/3͒16d O4+e−+Li+→͑Li2͒16c͑Li1/3,Ti5/3͒16d O4 Based on this equation,during the insertion process,lithium ions are in the tetrahedral͑8a͒sites and the guest lithium ions move to the octahedral͑16c͒sites,thus the total insertion capacity is determined by the number of free octahedral sites.The merits of adopting spinel Li4Ti5O12include itsﬂat electrical potential,nearly zero volume change,and excellent reversibility during the insertion/extraction process of Li ions.Li4Ti5O12thinﬁlm prepared by the sol-gel process for lithium battery electrodes has been reported in the past.8-10The sol-gel growth method is known to be difﬁcult to incorporate into the con-ventional semiconductor process.This article reports the successful growth of spinel Li4Ti5O12thinﬁlms using a radio frequency͑RF͒magnetron sputtering technique.Through a series of examinations of the crystallinity,surface morphology,and electrochemical properties of the high quality Li4Ti5O12thinﬁlm,this paper demonstrates the great potential of Li4Ti5O12used as the material of the electrodes of solid-state thin-ﬁlm batteries.ExperimentalLi4Ti5O12thinﬁlms were deposited by rf magnetron sputtering from a2in.diameter target onto Au͑100nm͒/ Ti͑10nm͒/SiO2/Si substrate maintained at various temperatures in the range of500-700°C.The substrate was adhered to the surface of the heater by a silver paste,and the temperature was determined bythe thermocouple in the heater.All substrates were cleaned in anorganic solvent͑acetone,methanol,isopropanol͒using a ultrasoniccleaner.The background pressure of the chamber before the heating of the substrate was less than10−5Torr.Auﬁlm functions as acurrent collector,while the Ti layer is the buffer layer that improves the adhesion between Au and SiO2.These two metal layers were deposited by standard dc magnetron sputtering.The Li4Ti5O12target was prepared by the solid-state reaction of TiO2and Li2CO3pow-ders.The mixed powder was calcined at800°C.Then it was re-ground,cold pelletized,and sintered at950°C in the ambient air.The X-ray diffraction͑XRD͒patterns showed a pure spinel phase with the space group Fd3¯m.Before the deposition,the target was presputtered for about20min.Theﬁlms were deposited at the pres-sure of30mTorr with the mixed Ar/O2͑3:2͒gas,and the power density was estimated to beϳ4W/cm2.Allﬁlms have a thickness around230nm.The crystal structure was examined by an X-ray diffractometer͑MAC Science͒employing Cu K␣line.The surface morphologies of Li4Ti5O12ﬁlms deposited at various temperatureswere observed with a JEOL6500F scanning electron microscope ͑SEM͒.The electrochemical properties of the oxideﬁlms were measuredin a two-electrode cell at room temperature.The cell uses an oxideﬁlm as the working electrode combined with a lithium metal foil asthe counter electrode.In the cell,the electrolyte was prepared by adopting1M LiPF6dissolved in a solution of ethylene carbonate ͑EC͒and ethylmethyl carbonate͑EMC͒with the volume ratio of 1:1.All cells were assembled inside the argon-ﬁlled glove box.For galvanostatic cycling testing,cells were discharged and charged at the constant current density of10␮A/cm2between1.0and2.0V. Cyclic voltammetry͑CV͒was performed at a sweep rate of 0.5mV/s for the characterization of theﬁlm electrode.ResultsTexture and crystallinity of the as-deposited thinﬁlms.—Figure 1shows the X-ray diffraction͑XRD͒patterns of the Li4Ti5O12thin ﬁlms grown on the Au/Ti/SiO2/Si substrate at different deposition temperatures.The well-crystallized thinﬁlm can be obtained at the deposition temperatures above500°C,and it exhibits a texture growth in the͑111͒plane.The texture growth along certain direc-tions is beneﬁcial to the performance of the thin-ﬁlm electrode.11 These thinﬁlms are colorless insulators,as expected.As the sub-strate temperature is increased,the crystallinity of theﬁlms is sub-z E-mail:ycliao@.tw Journal of The Electrochemical Society,152͑4͒A653-A657͑2005͒0013-4651/2005/152͑4͒/A653/5/$7.00©The Electrochemical Society,Inc.A653stantially improved,and it shows a highly preferred orientation along the ͓111͔,which is the major diffusion channel of Li ion.As mentioned earlier,the Au layer functions as the current col-lector for the electrode.Surprisingly,we ﬁnd that this Au layer en-hances the crystallinity of the as-grown thin ﬁlms,thus gold acts as a buffer layer between the substrate and the Li 4Ti 5O 12ﬁlm as well.As shown in Fig.1,the Au layer also exhibits the preferred ͑111͒orientation at the deposition temperature.The preferred orientation of the Au buffer layer provides a better template to grow ͑111͒-oriented Li 4Ti 5O 12ﬁlms.This statement is proved by comparing the XRD patterns between the Li 4Ti 5O 12ﬁlms deposited on the sub-strates Au/Ti/SiO 2/Si and SiO 2/Si ͑Fig.2͒.The ͑111͒peak of Li 4Ti 5O 12ﬁlm grown at 700°C is enhanced by using the Au/Ti/SiO 2/Si substrate,while the amorphous SiO 2layer did not act as a good template to deposit Li 4Ti 5O 12ﬁlm.The preferred orientation along ͓111͔in the Au layer also plays an important role here.Our experimental results indicate that there is no preferred orientation in the Li 4Ti 5O 12ﬁlm deposited on a gold foil without a speciﬁc texture.This gives further support to the above statement.The lattice constant of Li 4Ti 5O 12ﬁlm deposited on Au/Ti/SiO 2/Si,calculated from the XRD data,does not show any speciﬁc trend with the deposition temperature.The average of cubic lattice constants of the four samples is 8.291Åwith a standard deviationof 0.006Å.This value is only 0.81%less than the bulk value ͑8.358Å͒of Li 4Ti 5O 12.Perhaps it is the strain of gold ͑2a 0=8.158Å,a 0is the cubic lattice constant of gold ͒that leads to this result.To conclude the discussion on the XRD data,the gold layer on the substrate can promote the texture growth of Li 4Ti 5O 12along ͓111͔.The evolvement of surface morphology of Li 4Ti 5O 12ﬁlm with the deposition temperature is shown in Fig.3.There exists a transi-tion of surface morphology around the growth temperature of 650°C.At the deposition temperature of 600°C,the Li 4Ti 5O 12ﬁlm is smooth and shows densely packed grains ͑Figs.3a and 4a ͒.Above 650°C,more dispersed island-like grains emerge in the ﬁlm,as shown in the cross-sectional SEM image of the sample deposited at 700°C ͑Fig.4b ͒,and the ﬁlm exhibits a rougher surface.The length scale of this porous structure is around 0.1-0.2␮m.This kind of structure does not exist in the Li 4Ti 5O 12ﬁlm grown on the SiO 2/Si substrate at the same growth temperature,which is demonstrated in Fig.4c.The formation of these grain structures should be attributed to the presence of islands on the Au layer.These islands,which form preferentially along the ͓111͔plane,serve as the nucleation sites for the depositing Li 4Ti 5O 12materials.Consequently,the preferred ori-ented Li 4Ti 5O 12grains with good crystallinity and the island-like structure appear only on the Au-buffered substrate.This is consistent with our XRD results.Electrochemical measurement of the as-deposited thin ﬁlms .—Figure 5shows the CVs obtained from the Li 4Ti 5O 12ﬁlms grown at various substrate temperatures.All cyclic voltammogram measurements were operated in the potential range between 1.0and 2.0V at a scan rate of 0.5mV/s.The measurement results indicate that the primary insertion and extraction potential of Li ion are in a range between 1.5and 1.6V,which have been suggested resulting from the coexistence of the spinel phase and the rock-salt phase during the extraction and insertion processes of Li +ions.12The CV diagrams clearly show that the shape and peak current density of redox peaks depend on the growth temperature.As increasing the deposition temperature,the difference in the peak potential and the width of the redox peak reduce gradually.This reveals the better crystallinity of the ﬁlm grown at a higher temperature.The value of the potential,which is 1.54and 1.59V in Li insertion and extraction of the ﬁlm deposited at 700°C respectively,agrees with the typical value of Li 4Ti 5O 12.13This result indicates that the insertion and extraction of lithium ions are easier to accomplish in the ﬁlm syn-thesized under higher deposition temperature.The observation is consistent with the previous data that the ﬁlms grown at higher temperature exhibits better crystallinity and preferred orientation.These ﬁlms provide more reversible channels for Li ions to diffuse in the three-dimensional framework of Li 4Ti 5O 12.14Figure 6shows the discharge behaviors between 1.0and 2.0V of the ﬁlms deposited at various temperatures at the constant current density of 10␮A/cm 2.All these as-grown ﬁlms show the potential plateau around 1.55V,which is the typical redox value of spinel-phase Li 4Ti 5O 12.The discharge capacity for the ﬁlms deposited at 700°C is about 53␮Ah/cm 2␮m,and it is much greater than the ﬁlms deposited at 600°C.These observations are consistent with the results of cyclic voltammograms,where the peak current density relating to the capacity is enhanced signiﬁcantly from the deposition temperature of 600to 650°C.The capacity of the deposited thin ﬁlm increases substantially as the deposition temperature over 650°C.However,the crystallinity does not change drastically above 650°C.This suggests that the crystallinity of the as-grown ﬁlm is not the sole reason responsible for the large energy capacity.The plot of both ⌬2␪of ͑111͒diffraction peak and the discharge capacity conﬁrms this suggestion further.In the left axis of Fig.7,it shows that the crystallinity of Li 4Ti 5O 12ﬁlm improves gradually with rais-ing the growth temperature while there is a signiﬁcant enhancement of discharge capacity above 650°C,as shown in the right axis.The transitions of electrochemical properties coincide with the transition of surface morphology ͑Fig.3and 4͒.It is apparent that thesurfaceFigure 1.XRD patterns of the Li 4Ti 5O 12ﬁlms deposited on Au/Ti/SiO 2/Si at various deposition temperatures.It shows that both Li 4Ti 5O 12ﬁlm and the gold layer have the preferred orientation ͑111͒.Figure 2.XRD patterns of the Li 4Ti 5O 12ﬁlms on the two substrates Au/Ti/SiO 2/Si and SiO 2/Si grown at 700°C.The ﬁlm on Au/Ti/SiO 2/Si has a much better crystallinity than the ﬁlm on SiO 2/Si.A654Journal of The Electrochemical Society ,152͑4͒A653-A657͑2005͒morphology of the ﬁlm also plays an important role on the capacity.Owing to the ﬁnite diffusion length of Li ions in Li 4Ti 5O 12,Li ions cannot fully penetrate into the grains.Those island-like grains that exist in the ﬁlms deposited at higher temperatures provide much more effective area for the insertion of Li ions.This statement is inagreement with the previous study on the relationship between the charge capability and the particle size of Li 4Ti 5O 12.15In that paper,Kavan et al.showed that the charge capacity is proportional to the surface area of Li 4Ti 5O 12powder before the particle size reaches to few tens of nanometers.Therefore,the high capacity of Li 4Ti 5O 12ﬁlm deposited on Au/Ti/SiO 2/Si at 700°C results from both the rougher island-like grains and the good crystallinity,and conse-quently,it has sharp redox peaks and a large capacity.ConclusionsSpinel-phase Li 4Ti 5O 12thin ﬁlms are successfully grown by rf magnetron sputtering on Au/Ti/SiO 2/Si substrate.Thedeposi-Figure 3.SEM images of the surface morphology of Li 4Ti 5O 12thin ﬁlms deposited on Au/Ti/SiO 2/Si at ͑a ͒600,͑b ͒650,and ͑c ͒700°C.The surface morphology transits to a rougher one at the deposition temperature above650°C.Figure 4.SEM image of the cross-sectional structure of Li 4Ti 5O 12thin ﬁlms deposited at ͑a ͒600and ͑b ͒700on Au/Ti/SiO 2/Si and ͑c ͒700°C on SiO 2/Si.The ﬁlm on Au/Ti/SiO 2/Si grown at 700°C has a disperse-like grain structure while the same one deposited at 600°C shows the close-packed grains.This is attributed to the effect of the gold layer because the ﬁlm grown on SiO 2/Si at 700°C did not have a columnar structure.A655Journal of The Electrochemical Society ,152͑4͒A653-A657͑2005͒tion temperature inﬂuences the physical and electrochemical characteristics of the ﬁlms profoundly.Li 4Ti 5O 12ﬁlms grown on Au/Ti/SiO 2/Si can possess good crystallinity and proper surface morphology for the application in an electrode of a thin ﬁlm ing the optimized Li 4Ti 5O 12thin ﬁlm,the test cell of Li/Li 4Ti 5O 12exhibits sharp redox peaks and a large capacity.The capacity of this ﬁlm estimated by the discharge curve is 53␮Ah/cm 2␮m,and this value is comparable to those elec-trodes prepared by other methods.Both CV diagrams and dis-charge curves show that thin ﬁlm Li 4Ti 5O 12/Au/Ti/SiO 2/Si depos-ited by sputtering can be used as an excellent negative electrode in a lithium thin-ﬁlm battery.The results of this study demonstrate the potential for the realization of lithium-based solid-state thin-ﬁlm batteries.AcknowledgmentsThe authors thank Chen-En Wu for help taking the SEM images.We also thank Phillip Wu for help editing the English writing.This work is supported by the Taiwan National Science Council grant no.NSC91-2112-M-007-056.Figure 5.Cyclic voltammograms of Li 4Ti 5O 12thin ﬁlms deposited on Au/Ti/SiO 2/Si at various deposition temperatures ͑a ͒600,͑b ͒650,and ͑c ͒700°C in 1M in LiPF 6/EC +EMC at 0.5mV/s.The peak current density is signiﬁcantly enhanced above 650°C.The potentials of reduction peak ͑Li +insertion ͒and oxidization peak ͑Li +extraction ͒agree with otherstudies.Figure 6.Initial discharge curves of Li 4Ti 5O 12thin ﬁlms deposited on Au/Ti/SiO 2/Si at various temperatures.The substantial increase of charge capacity indicates that there should be some transition around the deposition temperature of 650°C.The capacity of the ﬁlm grown at 700°C reaches to nearly 90%of the theoretical value ͑60␮Ah/cm 2␮m ͒.Figure 7.The plot of both ⌬2␪of ͑111͒diffraction peak ͑left axis ͒and the discharge capacity ͑right axis ͒.It indicates that the enhancement of capacity of Li 4Ti 5O 12thin ﬁlm does not totally result from the improvement of crys-tallinity.Because the discharge curve of the ﬁlm deposited at 500°C did not have any observable plateau,the discharge capacity of this ﬁlm is nominally zero in our measurement.A656Journal of The Electrochemical Society ,152͑4͒A653-A657͑2005͒National Tsing Hua University assisted in meeting the publication costs of this article.References1. C.N.Polo da Fonseca,J.Davalos,M.Kleinke,M.C.A.Fantini,and A.Gorenstein,J.Power Sources,81-82,575͑1999͒.2.M.Yoshimura,K.S.Han,and S.Tsurimoto,Solid State Ionics,106,39͑1998͒.3. F.K.Shokoohi,J.M.Tarascon,B.J.Wolkens,D.Guyomard,and C.C.Chang,J.Electrochem.Soc.,137,1845͑1992͒.4. E.Ferg,R.J.Gummow,A.de Kock,and M.M.Thackeray,J.Electrochem.Soc.,141,L147͑1994͒.5.N.Koshiba,K.Takada,M.Nakanishi,K.Chikayama,and Z.Takehara,DenkiKagaku oyobi Kogyo Butsuri Kagaku,62,970͑1994͒.6.G.X.Wang,D.H.Bradhurst,S.X.Dou,and H.K.Liu,J.Power Sources,83,156͑1999͒.7.T.Ohzuku,A.Ueda,and N.Yamamoto,J.Electrochem.Soc.,142,1431͑1995͒.8.Y.H.Rho,K.Kanamura,M.Fujisaki,J.Hamagami,S.Suda,and T.Umegaki,SolidState Ionics,151,151͑2002͒.9.L.Kavan and M.Grätzel,Electrochem.Solid-State Lett.,5,A39͑2002͒.10.Y.H.Rho,K.Kanamura,and T.Umegaki,Chem.Lett.,2001,1322.11.K.-F.Chiu,F.C.Hsu,G.S.Chen,and M.K.Wu,J.Electrochem.Soc.,150,503͑2003͒.12.S.Scharner,W.Weppner,and P.Schmid-Beurmann,J.Electrochem.Soc.,146,857͑1999͒.13. D.Peramunage and K.M.Abraham,J.Electrochem.Soc.,145,2609͑1998͒.14. C.-M.Shen,X.-G.Zhang,Y.-K.Zhou,and H.-L.Li,Mater.Chem.Phys.,78,437͑2002͒.15.L.Kavan,G.Procházka,T.M.Spitler,M.Kalbáč,M.Zakalová,T.Drezen,and M.Grätzel,J.Electrochem.Soc.,150,1000͑2003͒.A657Journal of The Electrochemical Society,152͑4͒A653-A657͑2005͒。

基于全角模式下硅微轴对称陀螺调频控制技术

（
ｃｏｓ２ω０
ｔ－ｃｏｓ２ｋΩ
ｔ）
（６）
将上述２个信号经过低通滤波器滤除频率为２ω０的高频信号，经过三角函数运算得到角度：
θ
＝
１２
ａｒｃｔａｎ
ｓｉｎ２ｋΩ ｔｃｏｓ２ｋΩ ｔ
＝
１２
ａｒｃｔａｎ
ｓｉｎ［（ ωｃｗ－ω０）－（ ωｃｃｗ－ω０）］ｔｃｏｓ［（ ωｃｗ－ω０）－（ ωｃｃｗ－ω０）］ｔ
在本文控制系统中，设定 ωｃｗ＝ ω０＋ｋΩ，ωｃｃｗ＝ ω０－ｋΩ。在１个谐振子上，用ｃｏｓωｃｗｔ和ｃｏｓωｃｃｗｔ驱动ｘ模态，－ｓｉｎωｃｗｔ和ｓｉｎωｃｃｗｔ驱动ｙ模态，２个锁相环（ｐｈａｓｅｌｏｃｋｌｏｏｐ，ＰＬＬ）将顺逆时针模式控制在谐振状态，２个ＡＧＣ分别控制顺逆时针幅度。根据２个ＰＬＬ频率信息，进行相干解调和三角函数运算得到角度输出，控制框图如图４所示。
ＦｒｅｑｕｅｎｃｙＭｏｄｕｌａｔｉｏｎＣｏｎｔｒｏｌＴｅｃｈｎｏｌｏｇｙｏｆＷｈｏｌｅ⁃ａｎｇｌｅＭｏｄｅＢａｓｅｄｏｎＳｉｌｉｃｏｎＭｉｃｒｏｍｅｃｈａｎｉｃａｌＡｘｉｓｙｍｍｅｔｒｉｃＧｙｒｏｓｃｏｐｅｓ
ＹＡＮＧＹｉｎｇ⁃ｈｕｉ，ＬＩＵＪｉｎｇ，ＢＵＦｅｎｇ，ＦＡＮＢｏ，ＸＵＤａ⁃ｃｈｅｎｇ，ＧＵＯＳｈｕ⁃ｗｅｎ
·ｘ·＋［ ω０２－（ｋΩ）２］ｘ－２ｋΩ·ｙ＝０
（１）
·ｙ·＋［ ω０２－（ｋΩ）２］ｙ－２ｋΩ·ｘ＝０
式中：ｘ和ｙ分别为ｘ模态和ｙ模态方向上的振动位
移；Ω 为输入角速度；ω０为共振频率；ｋ为角增益，由陀螺的几何结构决定。

第三章二元相图及其类型

● 非平衡凝固总是导致凝固终结温度低
于平衡凝固时的终结温度。组织影响：晶内偏析、枝晶偏析(dendritic segregation) 性能影响：塑韧性降低、抗腐蚀性降低消除方法：扩散退火、均匀化退火固相线下 100-200℃ 长时间保温
4 具有极大点和极小点的匀晶相图
§3.3 共晶相图（eutectic phase diagram）指冷却过程中有共晶反应的相图(eutectic means easily melted) 如：Pb-Sn、Pb-Sb、Al-Si、Pb-Bi等 1 相图分析（以Sn-Pb合金为例）点：熔点、共晶点(eutectic point，invariant point)、最大溶解度点线：液相线、固相线、最大溶解度线(solid solubility limit line, solvus line) LE tE M N 共晶线、共晶反应(eutectic reaction)：区：三个单相区（L、α、β）、三个两相区（L+α、L+β、α+β）一个三相区共晶线(eutectic isotherm)
3 二元相图的建立关键：测定给定材料系中若干成分不同的合金的平衡凝固温度和相变温度方法：热分析法，金相法、硬度法、磁性法等
例：热分析法(thermal analysis)测定二元Cu-Ni合金 1) 配置不同成分的Cu-Ni合金；Cu, 75Cu25Ni, 50Cu50Ni, 25Cu75Ni, Ni 2) 将合金熔化，测定其冷却曲线； 3) 确定冷却曲线上的转折点，它们反应了合金状态的变化（凝固）； 4) 将这些数据绘入温度-成分坐标中； 5) 连接意义相同的点；分析相图：点、线、区
phasescoexist10040100100196119401001910019614019196140pseudoeutectic不平衡结晶条件下成分在共晶点附近的合金凝固后仍能获得共晶组织的现象不平衡共晶inonequilibriumeutectic在固溶体最大固溶度点内侧附近的合金在不平衡凝固时由于固相线下降在冷却过程中仍能发生共晶转变的现象离异共晶ii当合金中的先共晶相数量很多而共晶组织的量很少时共晶组织中的一相与先共晶相依附长大把另一相孤立出来形成两相分离的共晶组织34包晶相图peritecticphasediagram两组元在液态无限互溶固态下有限互溶或不互溶并发生包晶反应的相图如

基于HS-SPME-GC-MS与电子鼻分析芹菜贮藏期间挥发性物质的变化

芦佳琪，吴玉珍，张瑞，等. 基于HS-SPME-GC-MS 与电子鼻分析芹菜贮藏期间挥发性物质的变化[J]. 食品工业科技，2024，45（5）：212−222. doi: 10.13386/j.issn1002-0306.2023040101LU Jiaqi, WU Yuzhen, ZHANG Rui, et al. Change of the Volatile Compounds from Celery Leaves during Storage Based on HS-SPME-GC-MS and E-nose[J]. Science and Technology of Food Industry, 2024, 45(5): 212−222. (in Chinese with English abstract). doi:10.13386/j.issn1002-0306.2023040101· 分析检测 ·基于HS-SPME-GC-MS 与电子鼻分析芹菜贮藏期间挥发性物质的变化芦佳琪1，吴玉珍1，张　瑞1，韩晶晶1，熊爱生2，郁志芳1, *（1.南京农业大学食品科技学院，江苏南京 210095；2.南京农业大学园艺学院，江苏南京 210095）摘　要：采用顶空固相微萃取技术结合气相色谱-质谱联用（headspace solid phase microextraction-gas chromato-graphy-mass spectrometry ，HS-SPME-GC-MS ）和电子鼻技术分析了20.0 ℃贮藏期间芹菜叶片挥发性物质的组成和含量的变化。

结果显示，采用HS-SPME-GC-MS 技术从芹菜中共检测到108种挥发性物质，单萜类（43.2%~52.92%）和苯酞类（19.93%~28.97%）为主要组分，其中D-柠檬烯含量丰富（6600.64~48566.12 μg/kg ）。

Pulsar microstructure and its quasi-periodicities with the S2 VLBI system at a resolution o

a r X i v :a s t r o -p h /0107073v 4 2 O c t 2002Astronomy &Astrophysics manuscript no.(will be inserted by hand later)Pulsar microstructure and its quasi-periodicities with the S2VLBI system at a resolution of 62.5nanosecondsM.V.Popov 1,N.Bartel 2,W.H.Cannon 2,3,A.Yu.Novikov 3,V.I.Kondratiev 1,and V.I.Altunin 41Astro Space Center of the Lebedev Physical Institute,Profsoyuznaya 84/32,Moscow,117997Russia2York University,Department of Physics and Astronomy,4700Keele Street,Toronto,Ontario M3J 1P3Canada 3Space Geodynamics Laboratory/CRESTech,4850Keele Street,Toronto,Ontario M3J 3K1Canada 4Jet Propulsion Laboratory,4800Oak Grove Drive,Pasadena,CA 91109U.S.A.Received/AcceptedAbstract.We report a study of microstructure and its quasi-periodicities of three pulsars at 1.65GHz with the S2VLBI system at a resolution of 62.5ns,by far the highest for any such statistical study yet.For PSR B1929+10we found in the average cross-correlation function (CCF)broad microstructure with a characteristic timescale of 95±10µs and conﬁrmed microstructure with characteristic timescales between 100and 450µs for PSRs B0950+08and B1133+16.On a ﬁner scale PSRs B0950+08,B1133+16(component II)and B1929+10show narrow microstructure with a characteristic timescale in the CCFs of ∼10µs,the shortest found in the average CCF or autocorrelation function (ACF)for any pulsar,apart perhaps for the Crab pulsar.Histograms of microstructure widths are skewed heavily toward shorter timescales but display a sharp cutoﬀ.The shortest micropulses have widths between 2and 7µs.There is some indication that the timescales of the broad,narrow,and shortest micropulses are,at least partly,related to the widths of the components of the integrated proﬁles and the subpulse widths.If the shortest micropulses observed are indeed due to beaming then the ratio,γ,of the relativistic energy of the emitting particles to the rest energy is about 20000,independent of the pulsar period.We predict an observable lower limit for the width of micropulses from these pulsars at 1.65GHz of 0.5µs.If the short micropulses are instead interpreted as a radial modulation of the radiation pattern,then the associated emitting sources have dimensions of about 3km in the observer’s frame.For PSRs B0950+08and B1133+16(both components)the micropulses had a residual dispersion delay over a 16MHz frequency diﬀerence of ∼2µs when compared to that of average pulse proﬁles over a much larger relative and absolute frequency range.This residual delay is likely the result of propagation eﬀects in the pulsar magnetosphere that contribute to limiting the width of micropulses.No nanopulses or unresolved pulse spikes were detected.Cross-power spectra of single pulses show a large range of complexity with single spectral features representing classic quasi-periodicities and broad and overlapping features with essentially no periodicities at all.Signiﬁcant diﬀerences were found for the two components of PSR B1133+16in every aspect of our statistical analysis of micropulses and their quasi-periodicities.Asymmetries in the magnetosphere and the hollow cone of emission above the polar cap of the neutron star may be responsible for these diﬀerences.Key words.pulsars:general –pulsars:radio emission,microstructure –methods:data analysis –methods:obser-vational1.IntroductionPulsar radio emission originates in a region of extremely small size,most likely from charged particles in the mag-netosphere traveling along the diverging dipole magnetic ﬁeld lines above the polar cap of a neutron star (e.g.,Ruderman &Sutherland 1975;Arons 1983).This emis-sion can be seen by an external observer only during short successive time windows separated by the neutron star’s rotation period.Within such a window,the radio signals2M.V.Popov et al.:Pulsar microstructure and its quasi-periodicitiesing neutron star.The radial modulation is likely related to plasma bunching and linked to the elementary emis-sion mechanism.In this model the spectrum of the radio emission is a function of the radial distance from the neu-tron star,and the beam width is frequency dependent. High frequency radiation is emitted closer to the neutron star and the beam is narrower,low frequency radiation is emitted further out and the beam is broader,reﬂecting the opening of the polar magneticﬁeld lines.The study of pulsar intensityﬂuctuations has largely the goal of prob-ing on the one hand the geometrical characteristics of the pulsar emission beam and its underlying magnetospheric structure and on the other hand the elementary emission mechanism.Pulsar radio emission is known to exhibitﬂuctuations over a broad range of timescales.Average pulse proﬁles can have up to seven components(Kramer1994)and together with their frequency dependent widths reﬂect best the underlying geometrical structure of the magne-tosphere(Rankin1983).Every individual pulse is com-posed of one or several separate subpulses.In general, the subpulsesﬂuctuate strongly within a single pulse and from pulse to pulse but have stationary characteristics and characteristic widths computed from their autocorrelation functions that are96%correlated with the width of the strongest component of the average pulse proﬁle(Bartel et al.1980).Like the average pulse proﬁles they most likely also reﬂect the geometrical structure of the mag-netosphere(Bartel et al.1980).The subpulses in their turn are often composed of micropulses or microstructure with typical timescales of about hundred to a few hundred microseconds,or several tenths of a degree in pulsar longi-tude(e.g.,Hankins1972;Kardashev et al.1978).In a few cases still much faster but well resolved individualﬂuctu-ations were recorded,for instance with a timescale down to2.5µs for PSR B1133+16(Bartel&Hankins1982,see also Bartel1978),the fastestﬂuctuations found for any pulsar apart from the Crab pulsar.For the latter pulsar sporadic giant pulses were observed which were still unre-solved at a time resolution of10ns(Hankins2000).For the broader micropulses,quasi-periodic structures were found in the veryﬁrst studies of single pulses with suﬃciently high time resolution.Hankins(1971)found many examples of regularly spaced micropulses with pe-riods of300to700µs for PSR B0950+08at a fre-quency of111.5MHz.Backer(1973),Boriakoﬀ(1976) and Cordes(1976a)have shown that PSR B2016+28 has quasi-periodic microstructure with periods rang-ing from0.6to 1.1ms at a frequency of430MHz. Soglasnov et al.(1981,1983)analyzed the statistics of quasi-periodicities for PSRs B0809+74and B1133+16 at102.5MHz.Cordes et al.(1990)studiedﬁve pulsars (including PSRs B0950+08and B1133+16)with quasi-periodic microstructure at several radio frequencies.They concluded that there are no preferred periods for quasi-periodicities that are intrinsic to a given pulsar and that there is no frequency dependence of the micropulse width and the characteristic period of the quasi-periodicity.Lange et al.(1998)studied seven bright pulsars,in-cluding our three,at1.41and4.85GHz with a time reso-lution between7µs and160µs.They did notﬁnd notable diﬀerences of microstructure parameters at diﬀerent fre-quencies.It is the topic of this paper to investigate micropulses and their quasi-periodicities and to help to understand whether they reﬂect the longitudinally modulated emis-sion pattern and the geometry of the magnetosphere(e.g., Benford1977)or instead are more eﬀected by the radially or intrinsically temporally modulated pulsar emission pat-tern(e.g.,Hankins1972;Cordes1981).The shortest mi-cropulses observable in a pulsar in particular may harbor essential clues about the nature of the emissionﬂuctua-tions in pulsars.To achieve a high time resolution one must digi-tally record the pulsar signal before detection with sub-sequent dispersion removal processing as originally de-scribed by Hankins(1971).Previous studies were based mainly on observations made with a time resolution of several microseconds to several tens of microseconds.A review of microstructure research is given by Hankins (1996).In this paper we present a statistical analysis of the properties of microstructure for PSRs B0950+08, B1133+16,and B1929+10at1650MHz with a time reso-lution of62.5ns,the most extensive such analysis yet for any pulsar and with one of the highest time resolutions ever used.2.ObservationsThe observations were made with the NASA Deep Space Network70-m DSS43radio telescope at Tidbinbilla, Australia.PSRs B0950+08and B1133+16were observed on10May2000and PSR B1929+10on24April1998.The data were recorded continuously with the S2 VLBI system(Cannon et al.1997;Wietfeldt et al.1998) in the2-bit sampling mode in the lower sideband from 1634to1650MHz and the upper sideband from1650 to1666MHz.Left circular polarization was recorded for both frequency channels.The observations were made in absentia which is more typical for VLBI observations.In general,pulsar observations with the S2VLBI system can be made at any of the∼30radio telescopes worldwide which are equipped with such a system,in the same way VLBI observations are made without the need for the in-vestigator’s presence.In eﬀect,a dedicated pulsar back-end at the observing station is replaced with a software package on the workstation at the investigator’s home in-stitution.3.Data reductionThe tapes were shipped to Toronto and played back through the S2Tape-to-Computer Interface(S2-TCI)at the Space Geodynamics Laboratory(SGL)of CRESTech on the campus of York University.The S2-TCI system transfers the baseband-sampled pulsar data to computerM.V.Popov et al.:Pulsar microstructure and its quasi-periodicities 3Table 1.Pulsar characteristics and ﬁxed parameters:P is the pulsar period;DM is the dispersion measure for a dispersion constant:αd =2.41×10−16cm −3pc ·s;δt cal is the computed time delay between the two frequency channels based on DM,the standard errors are <0.1µs;N is the approximate total number of pulsar periods observed;N p is the number of selected strong pulses used to compute the CCFs.For PSR B1929+10a distinction is made between the number used to compute the average CCF and the number (in parentheses)used to compute the individual CCFs for the analysis of individual pulses;N µis the number of microstructure features revealed;N µ−QP is the number of detected quasi-periodicities;N no −µis the number of smooth structureless pulses;T is the number of samples for the duration of the pulse window used to calculate the CCF;SNR is the signal-to-noise ratio of the mean pulse intensity in the ON-pulse window averaged over all pulses selected for processing.It is a measure of the relative increase of the antenna temperature in the ON-pulse window.For the speciﬁc deﬁnition of SNR ,see text.0950+080.2532.9702a 89.11400022571656811310720.291133+16(I) 1.1884.8471a 145.43000240362544415242880.631133+16(II)145.4132165134515242880.331929+100.2263.1760b95.315500998(492)1093602142621440.28I off ,where I on is the mean intensity inthe ON-pulse window after subtraction of the mean in-tensity in the OFF-pulse window, I oﬀ .The SNR so de-ﬁned corresponds to the relative increase of the antenna temperature in the ON-pulse window and is therefore rel-atively small even for strong pulses.We used SNR =0.1as a threshold for pulse selection.The approximate total number of pulses,N ,observed and the number of selected pulses,N p ,are listed for each pulsar in Table 1.This ap-proach reduced the amount of data by a factor of several hundred and enabled us to carry out the subsequent signal processing more eﬃciently.Having determined the pulse windows and selected strong pulses we further processed the recorded (raw)sig-nal by decoding the signal amplitude sampled in two bits.Two-bit sampling of the amplitude of Gaussian random noise is widely used in VLBI observations.The decod-ing is generally done using four levels with integer values equal to −3,−1,+1,+3(Thompson et al.1988).These values reasonably represent the signal while the threshold level where the sampler switches from 1to 3and from−1to −3is equal to the current root-mean-square (rms)deviation (+1σand −1σ,respectively)of the signal.In order to preserve this condition during observations,the S2VLBI data acquisition system (S2-DAS)has an auto-matic gain control (AGC).For pulsar observations with the S2-DAS it is preferable to switch oﬀthe AGC and instead use the manual gain control with the gain ﬁxed,or if left switched on,to choose a suﬃciently long time constant for the AGC loop.Either option has the advan-tage of preventing the sampler from experiencing sudden gain discontinuities inside a pulse window.For our obser-vations the AGC was inadvertently left switched on,but fortunately the gain was found to be constant inside the selected pulse windows in the majority of cases.Therefore the threshold level could relatively easily be adjusted dur-ing the analysis after the observations to reﬂect the larger voltage variations in the ON-pulse window.We changed the decoding values through the data records from ±1and ±3to real values that correspond to the current ±1σlev-els in accordance with the technique developed by Jenet &Anderson (1998).We computed the new levels from the quasi-instantaneous rms values of subsequent portions of the data records,each 100µs long,to approximately match the dispersion smearing time across the 16-MHz bandwidth.The next step in our data processing routine was the removal of the dispersion caused by the interstellar medium.The predetection dispersion removal technique itself (Hankins 1971)consists of a Fourier transform of the decoded signal followed ﬁrst by amplitude corrections for the generally non-uniform receiver frequency bandpass and phase corrections for the dispersion delay,and then by an inverse Fourier transform back to the time domain.In particular,for the phase corrections of the dispersion delay,δΦ(ν),at the observing frequency,ν,we used4M.V.Popov et al.:Pulsar microstructure and its quasi-periodicitiesδΦ(ν)=δΦ(ν0+∆ν)=2πν30∆ν2 1−∆νM.V.Popov et al.:Pulsar microstructure and its quasi-periodicities5 Table2.Observed pulsar parameters:δt obs is the observed time delay between the two frequency channels;δt obs−δt cal is the diﬀerence between the observed and computed time delay for the two frequency channels;τµ−broad andτµ−narrow are the characteristic timescales of the microstructure determined from the average cross-correlation functions(see text);τµ−shortest is the shortest width found for the observed micropulses;t1/2is the FWHM of the average proﬁle or, in case of PSR B1133+16(I),of the component in the proﬁle(taken from Bartel et al.(1980)).For PSR B1133+16(II) no width is given in Bartel et al.(1980);the width is from Kramer(1994)interpolated between his values of a FWHM of a Gaussian at1.41and4.75GHz to1.65GHz.The parameter,τm,also from Bartel et al.(1980),is a measure of the typical subpulse width determined as the50%width(ignoring the zero-lag spike)of the average ACF of single pulses(for PSR B1133+16τm=2.9±0.1ms,no distinction is made between the two components).0950+0887.2±0.3−1.9±0.3135±514±379.1 5.01133+16(I)143.1±0.2−2.3±0.2430±30−66.0±0.6−1133+16(II)143.1±0.2−2.3±0.2110±2011±3210.7±0.3−1929+1095.2±0.1−0.1±0.195±109±355.9±0.23.4±0.1σon1σoﬀ2I oﬀ1+I on26M.V.Popov et al.:Pulsar microstructure and its quasi-periodicities0.300.360.42-10001000C o r r e l a t i o n c o e f f i c i e n tTime lag ( )µsPSR B0950+080.390.42-80-4004080C o r r e l a t i o n c o e f f i c i e n tTime lag ( )µsPSR B0950+080.350.400.450.50-10001000C o r r e l a t i o n c o e f f i c i e n tTime lag ( )µsPSR B1133+16 (I)0.460.470.48-80-4004080C o r r e l a t i o n c o e f f i c i e n tTime lag ( )µsPSR B1133+16 (I)0.480.530.58-10001000C o r r e l a t i o n c o e f f i c i e n tTime lag ( )µsPSR B1133+16 (II)0.560.58-80-4004080C o r r e l a t i o n c o e f f i c i e n tTime lag ( )µsPSR B1133+16 (II)0.390.450.51-400400C o r r e l a t i o n c o e f f i c i e n tTime lag ( )µsPSR B1929+100.450.48-80-4004080C o r r e l a t i o n c o e f f i c i e n tTime lag ( )µsPSR B1929+10Fig.3.The average cross-correlation function (CCF)for PSR B0950+08,the ﬁrst (I)and second (II)component ofPSR B1133+16,and PSR B1929+10.The CCFs were calculated for the unsmoothed ON-pulse intensities recorded in the conjugate 16-MHz bands and then smoothed over a time interval of 1µs.The right column of the plots represents the very central portion of the CCFs shown in the left column.M.V.Popov et al.:Pulsar microstructure and its quasi-periodicities70.0130.01320.01340.01360.01380.0140.01420.0144-200-1000100200C o r r e l a t i o n c o e f f i c i e n tTime lag ( )µs0.0260.0270.0280.0290.030.0310.0320.0330.0340.035-300-200-1000100200300C o r r e l a t i o n c o e f f i c i e n tTime lag ( )µs0.0250.0260.0270.0280.0290.030.0310.0320.0330.034-600-400-2000200400600C o r r e l a t i o n c o e f f i c i e n tTime lag ( )µsFig.4.Examples of individual CCFs for PSR B1133+16(component II)in order of increasing complexity.The leftplot shows microstructure with one notable width only.The middle and the right plots show microstructure with two and three widths.The scale of the correlation coeﬃcients is not corrected for receiver noise.Our value for τµ−broad for PSR B0950+08is com-patible with earlier measurements between 130and 200µs (Rickett 1975;Cordes &Hankins 1977;Hankins &Boriakoﬀ1978;Lange et al.1998).For PSR B1133+16microstructure was reported in the range of ∼340to ∼650µs (Hankins 1972;Ferguson et al.1976;Ferguson &Seiradakis 1978;Cordes 1976a;Popov et al.1987;Lange et al.1998),comparable to our value of compo-nent I but three to sixfold larger than that for component II.For PSR B1929+10the width of microstructure has never been measured in the average ACF or CCF before.However,Lange et al.(1998)reported on the detection of structure on timescales around 150µs close to their eﬀective time resolution of 70µs.In the right column we display the central portions of the CCFs.For PSR B1133+16(I)no additional abrupt sharpening of the CCFs can be seen.However for PSRs B0950+08,B1133+16(II),and B1929+10an additional central spike was found,indicating particularly short mi-crostructure with characteristic timescales,τµ−narrow ,of order 10µs (see Table 2).Such short microstructure has never been seen in the average ACF or CCF of any pulsar.However,for the giant pulses from the Crab pulsar,mi-crostructure was found in the ACF of a single pulse with the width at the 25%level of the ACF of ≤1µs (Hankins 2000).4.2.2.Time delay of microstructure from the averagecross-correlation functionA close inspection of the inner part of the CCFs shows that the peak does not always occur exactly at the expected time delay.To quantify the discrepancy we measured the center of symmetry of the top part of the central portion of the CCFs in Figure 3and list it as δt obs in Table 2.To de-termine the standard errors,∆δt obs ,we followed Chashei &Shishov (1975)and used∆δt obs ∼4τµ8M.V.Popov et al.:Pulsar microstructure and its quasi-periodicities1234567100200300400500P e r c e n tMicrostructure time scale ( )µsPSR B0950+082468101214165001000150020002500P e r c e n tMicrostructure time scale ( )µsPSR B1133+16 (I)2468020*********24681012140100200300400P e r c e n tMicrostructure time scale ( )µsPSR B1929+10510152025305001000150020002500P e r c e n tMicrostructure time scale ( )µsPSR B1133+16 (II)246810020*********Fig.5.Histograms of timescales of detected microstructure in the individual CCFs of single pulses for PSRs B0950+08,B1133+16(components I,II),and B1929+10.The insets display histograms for the shortest timescales.three diﬀerent widths for the microstructure.For PSRs B0950+08and B1929+10very often several,up to ﬁve,diﬀerent structural scales were found in the same pulse.In these cases several values for the microstructure width were obtained from one pulse.The total number of values for the microstructure width is listed for each pulsar (and each component in case of PSR B1133+16)in Table 1as N µ.A number of single pulses had smooth CCFs with-out any distinct microstructure features.That number is given as N no −µin Table 1.Only one from 225pulses of PSR B0950+08,or less than 0.5%had no microstruc-ture.For PSR B1929+10about 3%of single pulse had no microstructure,while for PSR B1133+16about 17%and 38%of pulses had no microstructure in case of the ﬁrst and the second component,respectively.This ﬁnd-ing indicates even higher percentages of single pulses with microstructure than reported earlier (e.g.,Smirnova et al.1994;Lange et al.1998),if the results also hold for the weaker pulses which had to be ignored in our analysis be-cause of sensitivity reasons.The histograms of the microstructure widths are pre-sented in Figure 5.For all three pulsars they are skewed towards shorter widths.In general,they show a moderate rise from broader to shorter width starting at ∼200µsfor PSRs B0950+08and B1929+10and ∼800µs for the two components of PSR B1133+16.The rise becomes markedly sharper at ∼40µs for PSRs B0950+08and B1929+10and at ∼200µs for each of the components of PSR B1133+16,or at ∼0.08and ∼0.02%of P,respec-tively.The histograms peak at ∼20to 30µs for PSRs B0950+08and B1929+10and ≤50µs for the two com-ponents of PSR B1133+16.Towards shorter widths the histograms of PSRs B0950+08,B1133+16(I,see inset of plot),and B1929+10display a sharp cutoﬀat a width of ∼10µs,and of PSR B1133+16(II)at <10µs (not vis-ible in plot).The shortest widths measured are 7µs for PSR B0950+08,6µs and 2µs for PSR B1133+16(com-ponent I and II,respectively),and 5µs for PSR B1929+10(Table 2).The cutoﬀwidth and the shortest widths mea-sured are greater than a)the smoothing interval of 1µs used in the analysis of the individual CCFs and b)the expected scattering time for either of the pulsars,and are therefore intrinsic properties of the pulsars.Again,there is a diﬀerence for the ﬁrst and second component of PSR B1133+16.Micropulses with a width ≤50µs occur almost twice as frequent in component II than in component I.M.V.Popov et al.:Pulsar microstructure and its quasi-periodicities9 4.3.Short-term noiselike intensityﬂuctuationsOur average CCFs as well as our individual CCFs do notshow any microstructure features with a sub-microsecondtimescale.On the other hand,as was mentioned inSection4.1,strong pulses when plotted with the highesttime resolution contain bright sub-microsecondﬂuctua-tions(see Figure2).Also,Sallmen et al.(1999)reportedto have found intensityﬂuctuations from the Crab pulsarwhich were still unresolved at their highest time resolu-tion of10ns.Is it possible that“nanopulses”exist in ourdata with a width not much larger than our highest timeresolution of62.5ns?They may perhaps not be visiblein our histograms with more than100times wider bins.They could perhaps also be largely uncorrelated for thetwo bands and therefore not apparent in the CCFs.To in-vestigate the signiﬁcance of our fast intensityﬂuctuationswe have to compare their statistics with the statistics ofnoise.We use two approaches in our data analysis:1)com-putation of short-term ACFs with a time-lag resolutionof62.5ns for ON-pulse and OFF-pulse windows,and2)comparison of the distribution of the intensities of short-term(62.5ns)ﬂuctuations ON-pulse with the distribu-tion of such intensities OFF-pulse and also with theχ2-distribution for thermal noise.4.3.1.Short-term ACFsShort-term ACFs,R(τ),with1R(τ)=2 1+cos2πτ√10M.V.Popov et al.:Pulsar microstructure and its quasi-periodicities510152025300.00.51.01.52.0I n t e n s it y (a r b . u n it s )Time (ms)PSR B1133+16 (I)(L)(U)0.110.120.130.140.15-3.0-2.0-1.00.0 1.0 2.0 3.0C o r r e l a t i o n c o e f f i c i e n tTime lag (ms)0.0020.0040.00624681012141618N o r m a l i z e d p o w e r s p e c t r a l d e n s i t yFrequency (kHz)Fig.7.An example of single pulse intensities with quasi-periodic microstructure for PSR B1133+16(component I)recorded in the upper (U)and lower (L)sidebands (left)and the corresponding CCF (middle)and cross-power spectrum (right).For plotting purposes only,the intensities were smoothed with a time constant of 8µs,and the CCF was smoothed with a time constant of 1µs and displayed with an arbitrary scale.For the cross-power spectrum we plot only the frequency range above 2kHz,since the large power spectral density from features at lower frequencies would otherwise determine the scale completely.the quasi-periodicity.Second,in case of more than one iso-lated strong feature,such features can be relatively easily distinguished in the cross-power spectrum but not so in an ACF or a CCF.We selected a feature as “detected”if its power spectral density was larger than,or equal to,6rms in the spectrum on both neighboring sides of the feature,or if the power spectral density exceeded a reason-able threshold.The last condition was necessary to detect strong spectral features in the very low frequency range where the local rms variation could be overestimated be-cause of the frequent complexity of the spectral features.In case of approximately symmetric features,the width,∆f µ,was determined as the FWHM.In case of complex features we interpreted the feature as a blend of several narrow features and estimated the FWHM of the dom-inant unblended feature by measuring the half-width at half-maximum intensity from the apparently unblended side of the feature to the peak and then doubled that width.In Table 1we list the total number,N µ−QP ,of strong isolated features found in the cross-power spectra of N p single pulses for PSRs B0950+08,B1133+16(I,II),and B1929+10.5.1.1.Types of microstructure periodicitiesIn Figure 8we show diﬀerent types of cross-power spec-tra for several selected single pulses of PSR B1133+16.Similar types were also found for the other two pulsars.All spectra were normalized by their total power,i.e.the sum of all harmonics was set equal to unity.Visual inspection shows that all spectral features be-low 10kHz are substantially broader than the applied fre-quency resolution of about 100Hz.The spectra there-fore diﬀer substantially from random noise and reﬂect the properties of the pulsar emission.The spectra may be classiﬁed in four general categories in order of increasing complexity.The ﬁrst category com-prises spectra dominated by only one symmetrical feature (a-e).The second category comprises spectra with two or more isolated symmetrical features with their frequencies being approximately multiple integers of the lowest fre-quency at which an isolated feature could be identiﬁed (f,g).These two categories correspond to the “classic”quasi-periodicities.However they constitute only about 5%of all analyzed spectra,about the same percentage for all three pulsars.The third category covers the spectra with several symmetrical isolated features located at more or less ran-dom frequencies (h,i).About 30–35%of all spectra fall under this category.Finally,the fourth category comprises spectra with isolated features at random frequencies as in the third category,but where each isolated feature is not symmetrical but instead structurally more complex (j,k).This is the most numerous category;it contains about two thirds of all spectra of all three pulsars.5.2.Histograms of the microstructure periodIn Figure 9we show the histograms of the microstructure period,P µ(P µ=1/f µ),for PSRs B0950+08,B1133+16(I,II)and B1929+10.There are some general similari-ties between them.The histograms are skewed towards smaller microstructure periods.They have a relatively narrow peak at about 300µs for PSRs B0950+08and B1929+10and a broader peak at ∼800µs for com-ponent I of PSR B1133+16and ∼400µs for compo-nent II,two to fourfold larger than τµ−broad .The his-tograms fall oﬀsharply towards smaller periods.The widths of the histograms are relatively large.The bulk of microstructure periods (75%)falls in the range of 0.1–1.0ms for PSR B0950+08,0.2–3.0ms for component I of PSR B1133+16,0.1–2.0ms for component II of PSR B1133+16,and 0.2–0.7ms for PSR B1929+10.For。

2004-ML-Phase-diagram-organic-有机共晶

Some physicochemical studies on binary organic eutectic and monotectic alloys:p -dibromobenzene-m -aminophenol systemU.S.Rai *,Pinky PandeyDepartment of Chemistry,Faculty of Science,Banaras Hindu University,Varanasi 221005,India Received 13May 2003;received in revised form 15January 2004;accepted 24January 2004Available online 16April 2004AbstractThe phase diagram of p -dibromobenzene-m -aminophenol system,determined by the thaw–melt method,shows the formation of a eutectic at 86.8j C and a monotectic at 120.0j C at 0.9899and 0.0496mole fractions of p -dibromobenzene,respectively.Growth data for the pure components,the eutectic and the monotectic,determined by measuring the rate of movement of solid–liquid interface in a capillary at different undercoolings (D T )suggest the applicability of Hillig–Turnbull equation,v =u (D T )n ,where u and n are constants depending on the nature of materials involved.The values of enthalpy of fusion of the pure components,the eutectic and the monotectic were determined and from these values,the enthalpy of mixing,entropy of fusion,Jackson’s roughness parameter and excess thermodynamic functions were calculated.Optical microphotographs of the pure and binary materials show their characteristic features.D 2004Published by Elsevier B.V .Keywords:Eutectic alloys;Monotectic alloys;PDBB1.IntroductionIncreasing industrial and technological development has induced an extensive search for commercially and techni-cally useful advanced materials to keep in pace with the demands of the current civilization.Rapid investigations in the field of metallurgy and materials science are in progress to meet the ever-increasing requirements since the last few decades.The fundamental understanding of solidification process [1,2]and the properties of polyphase alloys have currently been a subject of extensive theoretical and exper-imental investigations.Metallic polyphase alloys,namely,metallic eutectics [3],monotectics [4]and intermetallic compounds [5]offer an interesting area of investigation in metallurgy and materials science with a view to develop new commercially and technically important materials.But some features of metals are disadvantageous and offer hindrance during their studies.Due to low transformation temperature,ease of experi-mentation,transparency,wider choice of materials and minimized density-driven convection effects,organic sys-tems [6–10]are being used as model systems for detailedinvestigation of the parameters which control the mecha-nism of solidification.In addition,these systems have witnessed [6,11,12]their potential use in physicochemical investigations of semiconductors,superconductors and NLO materials.The special features of organic systems have prompted a number of research groups [13]to work on organic eutectics,monotectics and addition compound-forming systems.Due to a limited choice of materials and the difficulties associated with the miscibility gap,monotectic alloys have received less attention in comparison to eutectic or molec-ular complex forming systems.But the last few decades have witnessed sincere efforts trying to dig out the reasons behind the various interesting phenomena associated with the monotectic systems [14].The role of interfacial energy and the wetting behavior,thermal conductivity and buoy-ancy effects in a phase-separation process have been the subject of great discussion.The use of monotectic systems for space shuttle experiments [15]under reduced gravity conditions and the possibility of production of supercon-ductors have encouraged many groups to work on their physicochemical aspects.Keeping all these points in view,para-dibromobenzene (PDBB)-meta-aminophenol (MAP)system is chosen for study.This system constitutes an organic analogue of a0167-577X/$-see front matter D 2004Published by Elsevier B.V .doi:10.1016/j.matlet.2004.01.040*Corresponding author.Tel.:+91-542-317190;fax:+91-542-217074.E-mail address:usrai@bhu.ac.in (U.S.Rai)./locate/matletMaterials Letters 58(2004)2943–2948typical nonmetal–nonmetal type of system where both the components namely,PDBB and MAP have high heat of fusion value being20.6and23.1kJ molÀ1,respectively. This system exhibits liquid state immiscibility that indicates the presence of a monotectic.As such,the PDBB-MAP system offers a good model system for academic study and its phase diagram,growth-kinetics,thermochemistry and the microstructural aspects have been reported in the present paper.2.Experimental2.1.Materials and their purificationPara-dibromobenzene(Fluka,Switzerland)was purified by recrystallizing from diethyl ether while m-aminophenol (S.D.Fine Chem.,India)was purified by zone refining technique.The purity of each compound was checked by determining their melting points and comparing the same with the literature value.The experimental values of melting points for PDBB and MAP are87.4and120.8j C while the literature values are87.0and123.0j C,respectively.2.2.Phase diagramPhase diagram of the PDBB-MAP system was estab-lished by the thaw–melt method[13,16].In this method,the two compounds were taken in different numbered test tubes and mixtures were prepared in the entire range of compo-sition.All the mixtures were first homogenized and then their thaw and melting temperatures as well as complete miscibility temperatures were recorded using a Toshniwal melting point apparatus and a precision thermometer that could read up to the accuracy of F0.5j C.2.3.Growth kineticsFor growth kinetic studies,the linear velocity of crys-tallization of the pure components as well as the polyphase materials was determined by the capillary method[16,17]. In this method,the rate of movement of the solid–liquid interface was determined at desired undercoolings in a U-shaped capillary(5mm diameter and150mm horizontal portion)fitted with a scale.The whole assembly is kept in a silicone oil thermostat.At each undercooling,a seed crystal of the material(same in the U-tube)was added for nucleation to set in and the rate of movement of the crystallizing front was recorded using a stopwatch and a sliding microscope.2.4.Enthalpy of fusionThe heat of fusion of pure components,eutectic and monotectic was determined by a differential scanning calo-rimeter(Mettler DSC-4000system).Indium was used to calibrate the system.The amount of the test sample and heating rate were about5mg and5K minÀ1,respectively. The values of enthalpy of fusion are reproducible within F1.0%.2.5.MicrostructureMicrostructures of the pure components and the binary materials were recorded by placing the molten material on a glass slide and nucleating the supercooled liquid by the solid of the same composition under a coverslip.Care was taken to get a unidirectional cooling.The solid was then placed on the platform of a Leitz laborlux D optical microscope and significant regions were photographed on suitable magnifi-cation with a camera attached to it.3.Results and discussions3.1.Phase diagramThe phase diagram of PDBB-SCN system(Fig.1), expressed in terms of composition and temperature,shows formation of a eutectic(0.0496mole fraction of PDBB) and a monotectic(0.9844mole fraction of PDBB)with a large liquid phase immiscibility[18].The eutectic,mono-tectic and the critical solution temperature are86.8,120.0 and138.0j C,respectively.The upper consolute temper-ature lies18.0j C above the monotectic horizontal.The two components are miscible in all proportions above the critical solution temperature(T c).The melting point of MAP decreases with increasing addition of PDBB in it up to point M.Beyond this point,even a slight addition of the second component results in the formation of two separate,mutually immiscible layers.Theimmiscibility Fig.1.Phase diagram of p-dibromobenzene-m-aminophenol system:(o) melting/miscibility temperature;(.)thaw temperature.U.S.Rai,P.Pandey/Materials Letters58(2004)2943–2948 2944region is shown by the area L1+L2bounded by curve MCM h and a part of the monotectic horizontal MM h.The point C at the top of the curve MCM h represents the maximum temperature above which the two liquids are miscible in all proportions and there exists a homoge-neous liquid solution L.Point C represents the critical solution point or consolute point and the corresponding temperature is known as the critical solution temperature (T c).The area L1+L2may be regarded to be made up of an infinite number of tie lines which connect the two liquid phases L1and L2present at the extreme sides of the diagram.These tie lines become progressively shorter until the ultimate tie line at the top of the area L1+L2 reduces to a point that corresponds to the critical solution temperature.There are three reactions of interest on solidification of the present system.The first reaction concerns phase sepa-ration,as the liquid is cooled below the critical solution temperature,and can be written as:L W L1þL2The second reaction known as monotectic reaction occurs when a liquid of monotectic composition(C m)is cooled through the monotectic horizontal(T m).In this reaction,a liquid L1decomposes into a solid phase(S1) (rich in MAP)and another liquid phase L2(rich in PDBB)as follows:L1g S1þL2The third reaction is the common eutectic reaction.On cooling the liquid of eutectic composition below the eutectic temperature,it decomposes to give two solids S1(rich in PDBB)and S2(rich in MAP)as:L2g S1þS2The monotectic reaction is very similar to the eutectic except that one of the product phases is a second liquid phase.3.2.Growth kineticsThe rate at which growth occurs depends on the molecular mechanism of incorporation of molecules at crystal surface.Various theories have been developed for the growth mechanism of pure components as well as organic eutectics and predicted square relationship be-tween crystallization velocity and undercooling.Hillig and Turnbull suggested the following relation for the growth rate:v¼uðD TÞnð1ÞWhere u and n are constants depending on the solidifi-cation behavior of the materials under investigation.The experimental data are plotted in the form of log v vs.log D T for pure as well as binary alloys.Straight lines are obtained indicating the validity of Eq.(1).The values of u and n have been calculated for a number of systems by various workers. Table1contains the list of crystallization velocity data for organic systems studied by other workers,whereas Table2 contains the same for the PDBB-MAP system(this case). The value of n is approximately2in most of the cases.This suggests that there is a square relationship between growth velocity and undercooling.Some deviation in the values of Table1Values of u and n for different systems studied by other groups Material u n References a-Naphthol0.00056 3.56[23]h-Naphthol0.00275 3.60Catechol0.00055 2.57 Naphthalene 1.51400 1.88m-Aminophenol0.00083 2.80 Phenanthrene0.00263 4.08a-Naphthol-Phenanthrene(eut.I)0.00055 2.22a-Naphthol-Phenanthrene(eut.II)0.00791 1.74h-Naphthol-Phenanthrene(eut.)0.00050 1.81h-Naphthol-m-Aminophenol(eut.I)0.00020 1.74h-Naphthol-m-Aminophenol(eut.II)0.00199 1.80a-Naphthol-h-Naphthol-Phenanthrene(eut.)0.00045 1.74a-Naphthol-h-Naphthol-Phenanthrene(peritec.)0.01514 1.25a-Naphthol-h-Naphthol-Catechol(eut.)0.00033 1.95a-Naphthol-Naphthalene-Catechol(eut.)0.00166 1.82a-Naphthol-h-Naphthol-m-Aminophenol(eut.)0.00057 1.77a-Naphthol-h-Naphthol-m-Aminophenol(peritec.)0.251200.88 Naphthalene 1.514 1.88[24] Picric acid0.273 1.56 Anthracene0.235 1.39 Naphthalene-Picric Acid(eut.I)0.005 1.37 Naphthalene-Picric Acid(eut.II)0.00005 2.42 Naphthalene-Picric Acid(complex)0.00002 3.75 Anthracene-Picric Acid(eut.I)0.058 2.15 Anthracene-Picric acid(eut.II)0.039 1.71 Anthracene-Picric acid(complex)0.064 1.55 Naphthalene0.4400 2.33[25] Durene0.14458 3.18 Naphthalene-Durene(eut.)0.0091 1.10Benzamide0.00335 3.33[26] Benzoic acid0.02285 2.00Benzoic Acid-Benzamide(eut.)0.0011 1.43 Naphthalene0.3548 2.33[27]p-Dichlorobenzene0.0331 2.47 Naphthalene-p-Dichlorobenzene(eut.)0.0011 3.50U.S.Rai,P.Pandey/Materials Letters58(2004)2943–29482945n from 2may be due to the difference in the bath temper-ature and the temperature of the growing interface.It is also observed for the PDBB-MAP system that the value of u for eutectic is higher than that of the pure components,in case of monotectic,it is smaller than those of the components.In addition,the value of u for eutectic is greater than that for the monotectic.These results can be explained by the mechanism proposed by Winegard et al.[19].According to them,the solidification of eutectic starts with the nucleation of one of the components.While the side by side growth mechanism is responsible for the growth of the eutectic,the alternate nucleation mechanism favors the solidification of the monotectic.The basic criterion for the determination of growth mechanism is the comparison of the temperature dependence of linear velocity of crystallization with the theoretically predicted equations (Fig.2).While normal growth generally occurs on rough interface and for this there is direct proportion-ality between crystallization velocity and undercooling,lateral growth is facilitated by the presence of steps,jogs,bends,etc.,and under such conditions,the relationship for the spiral mechanism follows the parabolic law given by Eq.(1).3.3.ThermochemistryThe process of solidification,resulting in phase trans-formation from liquid to solid consists of two discrete steps:(i)nucleation and (ii)growth,which occur one after the other.While nucleation depends on solid –liquid interface energy that can be calculated from the heats of fusion,the growth step depends on the entropy of fusion of the material under investigation and the thermal envi-ronment in which the crystal grows.It also depends on step edge energies,kink site energies and kinetic barrier to the molecular motion on the surface.Thus the values of heat of fusion of pure components and eutectics are very important in understanding the mechanism of solidifica-tion.In addition,different thermodynamic quantities such as entropy of fusion,enthalpy of mixing,Jackson’s roughness parameter and excess thermodynamic functions can be calculated from heat of fusion which throw light on the mechanism of solidification and the nature of interaction between the components forming the eutectic melt.The values of enthalpy of fusion determined by the DSC method are given in Table 3.For the purpose ofcomparison,the value of enthalpy of fusion calculated by the mixture law is also given in the same table.It is evident from the table that the calculated value is lower than the experimental value by 1.2kJ mol À1.This differ-ence is attributed to the formation of quasieutectic structure in the binary eutectic melt.Thermochemical studies [20,21]suggest that the structure of the eutecticmeltFig.2.Linear velocity of crystallization of p -dibromobenzene,m -amino-phenol,their eutectic and monotectic.Table 3Heat of fusion,entropy of fusion,Jackson’s roughness parameter and heat of mixing for p -dibromobenzene-m -aminophenol system MaterialsHeat of fusion (kJ mol À1)Entropy of fusion (J mol À1K À1)Roughness parameter (a )Heat of mixing(kJ mol À1)p -Dibromobenzene 20.657.3 6.9m -Aminophenol 23.158.67.1PDBB-MAP Eutectic (Exp.)21.960.87.3PDBB-MAPEutectic (Calc.)20.7 1.2PDBB-MAP Monotectic (Exp.)23.860.57.3Table 2Values of u and n for p -dibromobenzene,m -aminophenol,their eutectic and monotectic Materialu (mm s À1deg À1)n p -Dibromobenzene 3.3Â10À5 2.8m -Aminophenol 2.7Â10À5 2.2Eutectic 8.5Â10À3 2.9Monotectic1.0Â10À62.3U.S.Rai,P .Pandey /Materials Letters 58(2004)2943–29482946depends on the sign and magnitude of the enthalpy of mixing (D mix H )given by Eq.(2):D mix H ¼ðD f h Þexp :ÀR x i ðD f h o i Þð2ÞWhere the first term is the experimental value of enthalpy of fusion and the second term is its value calculated from the mixture law.Three types of structures are suggested:(i)quasieutectic for D mix H >0,(ii)cluster-ing of molecules for D mix H <0and (iii)molecular solution for D mix H =0.The positive value of enthalpy of mixing suggests that there is quasieutectic structure in the eutectic melt.Rastogi et al.[22]have reported cluster formation in case of napthalene-p -chloronitrobenzene and naphthalene-phenanthrene eutectic.They have also reported positive value of g E for h -naphthol-catechol,naphthalene-p -chlor-onitrobenzene,naphthalene-catechol,a -naphthol-h -naph-thol and napthalene-phenanthrene systems where interaction between like molecules in the eutectic phase is stronger.In some other paper Rastogi et al.[23]and Shukla et al.[24]have reported enthalpy changes on mixing in eutectic melts and disobeyence of mixture law in a few cases.The values of entropy of fusion,D f S ,of the pure components and the binary materials were calculated using the following relation:D f S ¼D f h Tð3Þwhere D f h is the enthalpy of fusion,and T is the meltingtemperature.The values of entropy of fusion of the pure components,the eutectic and the monotectic being com-parable suggest that the role of entropy in the melting of the polyphase alloys is comparable to that of the pure components.With a view to assess the quantitative measure of the deviation of the system from ideal behavior,some excess thermodynamic functions,namely,excess enthalpy (h E ),excess entropy (s E )and excess free energy (g E )were calculated using the method reported earlier [25–34]:g E ¼RT ½x 1ln c 11þx 2ln c 12ð4Þh E ¼ÀRT 2x 1d ln c 11d T þx 2d ln c 12d T ð5Þs E¼ÀRx 1ln c 11þx 2ln c 12þx 1T d ln c 11d T þx 2T d ln c 12d Tð6ÞAssuming that the heat of fusion is independent of temperature and the two components are miscible in theliquid phase only,the activity coefficient (c 11)of component i at the eutectic point was calculated using the relation:Àln x 1i c 1i ¼D f h oiR 1T À1T o i ð7Þwhere x i ,D f h i o and T i o are the mole fraction,heat of fusionand melting temperature of component i ,respectively,R is the gas constant and T is the melting temperature of the eutectic.The positive value [23,28]of excess free energy,g E (100J mol À1),suggests that the interactions between like molecules are stronger than those between unlike molecules.The positive values of h E (300J mol À1)and s E (0.4kJ mol À1K À1)correspond to the above value of excess free energy and play their role in the molecular interaction in the eutectic melt.3.4.MicrostructureThe microstructure [35]gives information about the size,shape and distribution of phases in polyphase materials.Normally,the properties of alloys are determined by their microstructure,which in turn,is controlled by the type,relative amount and morphology of phases involved.Ther-mal conductivity,entropy of fusion of phases,structure of the solid–liquid interface and the degree ofundercoolingFig.3.Microstructure of p -dibromobenzene-m -aminophenol eutectic Â300.Fig.4.Microstructure of p -dibromobenzene-m -aminophenol monotectic Â300.U.S.Rai,P .Pandey /Materials Letters 58(2004)2943–29482947are the other factors which control the microstructure.The eutectic microstructure of the present system(Fig.3)shows eutectic colonies.These colonies lie parallel to each other. Within the colonies,lamellar structure is found but the lamellae are broken due to high interfacial energy of one of the constituent phases.The monotectic(Fig.4)shows that nodules grow at different places and meet at some common boundaries.The monotectic microstructure shows grains with lamellar structure.These grains meet at common boundaries in the figure.4.ConclusionsThe following conclusions have been drawn from the present studies:(I)Phase diagram of the para-dibromobenzene-meta-aminophenol system is a typical monotectic one consisting of a monotectic and a eutectic phase-transformation reaction at0.050and0.990mole fractions of PDBB,respectively.(II)The growth kinetics data for the pure components,the eutectic and the monotectic determined by the capillary method suggest that growth takes place according to the Hillig–Turnbull equation,v=u(D T)n where v is the growth velocity,D T is the undercooling and u and n are constants depending on the nature of the materials involved.(III)Using the heat of fusion data determined by the DSC method,the entropy of fusion,enthalpy of mixing, Jackson’s roughness parameter,and excess thermody-namic functions were calculated.The enthalpy of mixing for the eutectic shows that there is quasieutectic structure in the eutectic melt.The calculation of the excess thermodynamic functions suggests that the interactions between like molecules are stronger than those between unlike molecules.(IV)While in the case of the eutectic microstructure of the present system,eutectic colonies are observed,the monotectic shows nodules growing at different places meeting at common boundaries. AcknowledgementsThanks are due to CSIR,New Delhi for financial assistance.References[1]R.Elliott,Eutectic Solidification Processing,Butterworths,London,1983.[2] D.M.Herlach,R.F.Cochrane,I.Egry,H.J.Fecht,A.L.Greer,Int.Mater.Rev.38(6)(1993)273.[3] A.K.Dohle,K.Nogita,J.W.Zindal,S.D.Mcdonald,L.M.Hogan,Metall.Mater.Trans.A32A(2001)949.[4] B.Majumdar,K.Chattopadhyay,Metall.Mater.Trans.31A(2000)1.[5]R.Caram,enkovic,J.Cryst.Growth198/199(1999)844.[6] D.O.Frazier,B.R.Facemire,U.S.Fanning,Acta Metall.34(1)(1986)63.[7]P.S.Bassi,R.P.Sharma,Indian J.Chem.35A(1996)133.[8]W.F.Kaukler,D.O.Frazier,Nature323(1986)50.[9]K.A.Blackmore,K.M.Beatty,M.J.Hui,K.A.Jackson,J.Cryst.Growth174(1997)76.[10]U.S.Rai,P.Pandey,Mol.Mater.12(2000)13.[11]J.P.Farges,Organic Conductors,Marcel Dekker,New York,1995.[12]T.Henningsen,N.P.Singh,R.H.Hopkins,R.Mazelsky,F.K.Hopkins,D.O.Frazier,O.P.Singh,Mater.Lett.20(1994)203.[13]J.Sangster,J.Phys.Chem.Ref.Data23(1994)295.[14]W.F.Kaukler,F.Rosenberger,P.A.Curreri,Metall.Mater.Trans.28A(1997)1705.[15]N.B.Singh,Sci.Rep.24(1987)212.[16]U.S.Rai,R.N.Rai,Chem.Mater.(Am.Chem.Soc.)11(1999)3031.[17]U.S.Rai,K.D.Mandal,Bull.Chem.Soc.Jpn.63(1990)1496.[18] B.Predel,J.Phase Equilib.18(1997)327.[19]W.C.Winegard,S.Mojka,B.M.Thall,B.Chalmers,Can.J.Chem.29(1957)320.[20]U.S.Rai,P.Pandey,Thermochim.Acta364(2000)111.[21]U.S.Rai,P.Pandey,R.N.Rai,J.Cryst.Growth220(2000)610.[22]R.P.Rastogi,N.B.Singh,P.Rastogi,N.B.Singh,J.Cryst.Growth40(1977)234.[23]R.P.Rastogi,D.P.Singh,N.Singh,N.B.Singh,Mol.Cryst.Liq.Cryst.73(1981)7.[24] B.M.Shukla,N.P.Singh,N.B.Singh,Mol.Cryst.Liq.Cryst.104(1984)265.[25]P.S.Bassi,R.P.Sharma,J.R.Khurma,Indian J.Technol.29(1991)115.[26] B.L.Sharma,P.S.Bassi,Indian J.Chem.23A(1984)303.[27] D.P.Sachdev,P.S.Bassi,J.Indian Chem.Soc.68(1991)650.[28]P.S.Bassi,B.L.Sharma,N.K.Sharma,S.Kumar,Indian J.Chem.27A(1988)1021.[29]J.Sangster,J.Phys.Chem.Ref.Data23(1994)295.[30] B.L.Sharma,R.Kant,R.Sharma,S.Tandon,Mater.Chem.Phys.82(2003)216.[31]U.S.Rai,R.N.Rai,Chem.Mater.(Am.Chem.Soc.)11(1999)3031.[32]U.S.Rai,P.Pandey,J.Cryst.Growth249(2003)301.[33]U.S.Rai,P.Pandey,J.Therm.Anal.Calorim.74(2003)141.[34]U.S.Rai,O.P.Singh,N.P.Singh,N.B.Singh,Thermochim.Acta71(1983)373.[35]G.A.Chadwick,Metallography of Phase Transformation,Butter-worths,London,1972.U.S.Rai,P.Pandey/Materials Letters58(2004)2943–2948 2948。

BinaryPhaseDiagrams：二元相图

Binary Phase DiagramsPurposeTo construct a liquid/vapor temperature-composition (T-X) phase diagram for a binary mixture of cyclohexane and ethanol.TheoryBinary mixtures of two volatile liquids exhibit a range of boiling behavior from ideal, with a simple continuous change in boiling point with composition, to nonideal, showing the presence of an azeotrope and either a maximum or minimum boiling point. In this experiment, the properties of a binary mixture of cyclohexane and methanol will be investigated by studying the change in boiling point with composition. You will construct a boiling point diagram and identify any nonideal behavior in the system.For ideal mixtures of liquids, the composition of the vapor phase is always richer in the component with the higher vapor pressure. According to Raoult's Law, the vapor pressure of component A is given byp A =xApA* [1]where x A is the mole fraction of A in solution and pA∗ is the vapor pressure of pure A. Actual vapor pressures can be greater or less than those predicted by Raoult's Law, indicating negative and positive deviations from ideality. In some cases, the deviations are large enough to produce maxima or minima in the boiling point and vapor pressure curves. At the maximum or minimum, the compositions of the liquid and vapor phases are the same, but the system is not a pure substance. This results in an azeotrope, a mixture which boils with constant composition.A distillation will not be able to completely separate the two components. Either the distillate or the residue will eventually reach the azeotropic composition and no further separation will occur.Simple distillation can be used to obtain a boiling point diagram so long as some method exists to analyze both the distillate and the residue. In practice, several mixtures of differing composition of the two liquids are distilled and samples of both the distillate and residue are taken. The temperature (boiling point) of each distillation is recorded and the composition of both the distillate and residue is determined. The analysis method should provide a measurement which changes significantly and continuously over the entire range of concentration, from one pure liquid to the other pure liquid. In many cases, the refractive index provides a suitable measure of concentration. A calibration curve must be obtained using known mixtures. The refractive index of an unknown mixture is then measured and the composition obtained using the calibration curve.ProcedureCalibration Curve1. Make up 5 mL each of 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 percent by volume ethanol solutions using volumetric pipets.2. Measure the refractive index for each of these solutions.3. Convert the percent volume concentrations into mole fraction.4. Construct a plot of mole fraction versus index of refraction.DistillationA simple distillation setup similar to that shown below is used. A two- or three-necked roundbottom flask should be used. This equipment should be in a hood.Have several Pasteur pipets available for taking samples of the distillate and residue. Also prepare twenty sample vials labeled V1 to V10 and L1 to L10 as discussed below. The vials marked V (for vapor) will be used to collect the distillate (the condensed vapor phase) and the vials marked L will be used to collect the residue (the liquid phase). Graduated cylinders should be used for measuring the pure liquids for the distillation.1. Place 75 mL of ethanol and 25 mL of cyclohexane in the distillation flask. Start thedistillation with an Erlenmeyer flask or beaker as your receiving vessel and continue until about 5 mL of distillate is collected and then discard. Now collect 5 more mL into sample vial V1. Record the temperature during this collection period. Turn off the heater and allow the boiling to stop, then transfer about 2 mL of the distillate into vial L1. Make sure that you cap the vials and record their refractive index soon thereafter.Repeat the process four more times, adding 25 mL of cyclohexane to the distillation flask each time.2. Start over with a mixture containing 95 mL of cyclohexane and 5 mL of ethanol. Distill andcollect samples of the distillate and residue as in part 1, labeling them V6 and L6,respectively. Repeat four more times adding 10 mL of ethanol to the distillation flask each time.3. During the lab period, using the second distillation apparatus, the boiling points for pureethanol and pure cyclohexane should be obtained. Also, record the atmospheric pressure. CalculationsUsing the distillation data and your calibration curve, plot the temperatures against the mole fraction of ethanol for both the liquid and vapor phases on the same plot. Make sure the data from the pure liquid distillations are included. Draw (this means do not perform a fit in excel, why?) two smooth curves, one through the liquid data (residue) and one through the vapor data (distillate).From your plot determine the azeotropic composition (as mass fraction and mole fraction) and the azeotropic temperature. Compare to a literature value.Questions1. What type of deviation from ideality (if any) does this system show? Rationalize thisbehavior in terms of the intermolecular forces expected for this system.2. How could one separate the components in an azeotrope? One of the most importantazeotropes is that formed in the ethanol-water system. Find the composition of thisazeotrope (use the literature) and also find a method for "breaking" this azeotrope. It must be possible since we can buy 100% ethanol and 100% water!3. Use the literature to find a binary mixture whose azeotropic mole fraction is roughly 0.504. A similar experiment can be conducted to obtain a solid/liquid temperature-compositionphase diagram. For solid/liquid systems, eutectics may form rather than azeotropes as is the case for liquid/vapor systems. Discuss the similarity between a eutectic and an azeotrope.。

电子电路分析与设计--模拟电子技术(答案)第14章

Chapter 1414.1 80(max) 4.5(max)56.25 mV o d io i v A v v v ==−=⇒=So(max)i rms v = ______________________________________________________________________________________14.2(a) 2 4.50.028125 mA 1604.5 4.5 mA 1L i i ==== Output Circuit 4.528 mA = 4.50.05625 V 80o i i v v v A −=−=⇒=−(b) 4.515 mA (min)300o o L L L v i R R R ≈==⇒=Ω______________________________________________________________________________________14.3 (1)2 V o v = (2)212.5 mV v = (3)4210OL A =× (4) 18 V v μ=(5)1000OL A =______________________________________________________________________________________14.4(a) ()42857.216.512012−=−=−=∞R R A CL 42376.211042857.22142857.215−=+−=CL A ()%0224.0%10042857.2142857.2142376.21−=×−−−− (b) ()634146.142.812012−=−=−=∞R R A CL 63186.1410634146.151634146.145−=+−=CL A ()%0156.0%100634146.14634146.1463186.14−=×−−−− ______________________________________________________________________________________14.5(a) (i) 90863.710291176.7191176.71028.647118.647144=×+=×⎟⎠⎞⎜⎝⎛+++=CL A (ii) %03956.0%10091176.791176.790863.7−=×− (b) (i) 84966.71091176.7191176.73=+=CL A (ii) %785.0%10091176.791176.784966.7−=×− ______________________________________________________________________________________14.6(a) 12091.151050005.1102110.15121241231212=⇒⎟⎠⎞⎜⎝⎛×+−=×⎟⎠⎞⎜⎝⎛++−=−−R R R R R R R R R R (b) 1160.1510512091.16112091.154−=×+−=CL A ______________________________________________________________________________________14.7()()5109991.890190900001.01×=⇒+=−OL OLA A ______________________________________________________________________________________14.8()()499911110002.01=⇒+=−=OL OLCL A A A ______________________________________________________________________________________14.9(a) ()()001.0121001.0121012±±=+=R R A 02.10979.2021.210max ==A 98.9021.2179.209min ==A So 02.1098.9≤≤A (b) 009.101002.11102.104max =+=A 969.91098.10198.94min =+=A So 009.10969.9≤≤A ______________________________________________________________________________________14.1010110012010011212and so that 111I L iL I i v v v v v v A R R R v v A v v v R R R R R −−=+=−=−⎛⎞+=++⎜⎟⎝⎠1vSo 01201211111I L i v v R R A R R R ⎡⎤⎛⎞=−+++⎢⎥⎜⎟⎝⎠⎣⎦ Then 012012(1/)11111CL I L i v R A v R A R R R −==⎡⎤⎛⎞+++⎢⎥⎜⎟⎝⎠⎣⎦ From Equation (14.20) for and L R =∞00R =02(1)1111L if i A R R R +=+⋅ a. For1 k i R =Ω 33(1/20)11111100201001100.05[0.01 1.0610]CL A −−=⎡⎤⎛⎞+++⎜⎟⎢⎥⎝⎠⎣⎦−=+×or3 4.521111090.8 1100CL if if A R R ⇒=−+=+⇒=Ω b. For10 k i R =Ω 34(1/20)111111002010010100.05[0.01 1.610]CL A −−=⎡⎤⎛⎞+++⎜⎟⎢⎥⎝⎠⎣⎦−=+× or 4.92CL A ⇒=−31111098.9 10100if if R R +=+⇒=Ω c. For100 k i R =Ω 35(1/20)1111110020100100100.05[0.01710]CL A −−=⎡⎤⎛⎞+++⎜⎟⎢⎥⎝⎠⎣⎦−=+×or 3 4.9651111099.8 100100CL if if A R R ⇒=−+=+⇒=Ω ______________________________________________________________________________________14.1121211111o CL i OL R R v A v R A R ⎛⎞+⎜⎟⎝⎠==⎡⎤⎛⎞++⎢⎥⎜⎟⎝⎠⎣⎦ For the ideal: 210.10150.002R R ⎛⎞+==⎜⎟⎝⎠0 ()(0.10)(10.001)0.0999ov actual =−= So 0.09995049.9510.0021(50)OL A ==+which yields 1000OLA = ______________________________________________________________________________________14.12From Equation (14.18) 211121111OL o o vf L o A R R v A v R R R ⎛⎞−−⎜⎟⎝⎠==⎛⎞++⎜⎟⎝⎠ Or 331131151011100(4.9999910)111 1.111011004.50449510o o v v v v ⎛⎞×−−⎜⎟−×⎝⎠=⋅=⎛⎞++⎜⎟⎝⎠=−×⋅1v ⋅ Now 11111i v v i K v R v −=≡Then 11i v v KR v −=1 which yields 111i v v KR =+ Now, from Equation (14.20) 3311510111011101001101005.001110(0.1)(0.01)45.154951.11K ⎡⎤+×+⎢⎥=+⎢⎥⎢⎥++⎢⎥⎣⎦⎡⎤×=+=⎢⎥⎣⎦Then ()()145.15495101452.5495i i v v v ==+We find31 4.50449510452.5495i o v v ⎡⎤=−×⎢⎥⎣⎦ Or 119.9536o vf i v A v ==− For the second stage,L R =∞ 332131111151011100 4.9504851011110011151049.6148511010011001(49.61485)(10)1497.1485o o o o v v K v v v v KR ⎛⎞×−−⎜⎟⎝⎠′′=⋅=−⎛⎞+⎜⎟⎝⎠⎡⎤⎢⎥+×≡+=⎢⎥⎢⎥+⎢⎥⎣⎦′===++1v ×⋅ Then 321 4.950485109.95776497.1485o o v v −×==−So 2(9.9536)(9.95776)99.12o vf vf iv A A v ==−−⇒= ______________________________________________________________________________________14.13a.10113120I i v v v v v R R R R −−++=+ (1) 0131223111I i i v v v R R R R R R R ⎡⎤++=+⎢⎥++⎣⎦00001020L d L v v A v v v R R R −−++= (2) or 010*******L dL A v v v R R R R R ⎡⎤++=+⎢⎥⎣⎦ 13I d i i v v v R R R ⎛⎞−=⋅⎜⎟+⎝⎠ (3)So substituting numbers:011110201040401020I v v v 1⎡⎤++=+⎢⎥+⎣⎦+ (1)or10[0.15833][0.025][0.03333]I v v v =+ 410(10)11110.540400.5d v v v ⎡⎤++=+⎢⎥⎣⎦ (2) or[][]()4013.0250.025210dv v =+×v ()11200.66671020I d v v v v −⎛⎞=⋅=⎜⎟+⎝⎠I v − (3)So[][]()()()4013.0250.0252100.6667I v v v =+×−1v (2) or []44013.025 1.33310 1.33310I v v =×−×v ) From (1):()(100.15790.2105I v v v =+ Then []()()44003403.025 1.33310 1.333100.15790.21052.107810 1.052410I I I v v v v v v =×−×+⎡⎤⎣⎦⎡⎤⎡⎤×=×⎣⎦⎣⎦or 0 4.993CL I v A v == To find:if R Use Equation (14.27) ()31210.50.5114010110.50.50.51104014040(40)(1.5125){(0.125)(1.5125)0.0003125}25I d I d i v v i v ⎛⎞++⎜⎟⎝⎠⎧⎫⎛⎞⎛⎞=+++−−⎨⎬⎜⎟⎜⎟⎝⎠⎝⎠⎩⎭=−v −or (1.5125){0.18875}25I I d i v =−v I Nowand(20)d I i I v i R i ==1(20)I I v v i =− So(1.5125)[(20)][0.18875]25(20)[505.3](0.18875)I I I I I i v i i i v =−⋅−= or 2677 k I I v i =Ω Now 102677 2.687 M if if R R =+⇒=ΩTo determine 0:f R Using Equation (14.36)30200111110400.5111020L f i A R R R R R ⎡⎤⎡⎤⎢⎥⎢⎥⎢⎥⎢⎥=⋅=⋅′⎢⎥⎢⎥++⎢⎥⎢⎥⎣⎦⎣⎦or0 3.5 f R ′=Ω Then 0 1 k f R =ΩΩ0 3.49 f R ⇒=Ωb. Using Equation (14.16) 35(10)(0.05)%10CL CL CL CL dA dA A A ⎛⎞=−⇒=−⎜⎟⎝⎠ ______________________________________________________________________________________14.14(a)(b) (i)()o O I OL O i O I R A R υυυυυ−−=− ⎟⎟⎠⎞⎜⎜⎝⎛++=+o OL o iO o I OL i IR A R R R A R 11υυυ ⎟⎟⎠⎞⎜⎜⎝⎛×++=⎟⎟⎠⎞⎜⎜⎝⎛×+110511101110510133O I υυ()(33100011.5100001.5×=×O I υυ) 9998.0=IO υυ (ii) ()ix o x OL x x R V R V A V I +−−= 101110511113+×+=++==i o OL of x x R R A R V IΩ≅2.0of R______________________________________________________________________________________14.151011210121201040111201040201040I I I I v v v v v v v v v v −−−+=⎡⎤++=++⎢⎥⎣⎦ andso that 00L v A =−1v 010L v v A =−Then 1203200120000117(0.05)(0.10)4040210[2.5087510]1.993 3.9862 1.9930.352I I I I v v v v v v v v v %v v −⎧⎫⎛⎞+=−+⋅⎨⎬⎜⎟×⎝⎠⎩⎭=−×⇒=−−ΔΔ−=⇒= ______________________________________________________________________________________14.16224040.840105B v v v ⎛⎞⎛⎞===⎜⎟⎜⎟+⎝⎠⎝⎠2v (1) 011040A A v v v v −−= 011110401040A v v v ⎛⎞+=+⎜⎟⎝⎠ (2)10(0.1)(0.025)(0.125)A v v v += 000()L d L B A v A v A v v ==−(3)or002020020[0.8]0.80.8L A A LA L v A v v v v v A v v v A =−−=−⇒=−Then 01020120320021(0.1)(0.025)(0.125)0.80.125(0.1)(0.1)0.02510[2.512510]3.98010.01990.49754L d d d v v v v A v v v v v A v v A %A −⎡⎤+=−⎢⎥⎣⎦⎡⎤−=−+⎢⎥⎣⎦=−×⇒==−Δ⇒=⇒ ______________________________________________________________________________________14.17a. Considering the second op-amp and Equation (14.20), we have 211111001010.101100.1(0.1)(11)10.1if R ⎡⎤⎢⎥+=+⋅=+⎢⎥⎢⎥+⎢⎥⎣⎦ So 20.0109 k if R =ΩThe effective load on the first op-amp is then 120.10.1109 k L if R R =+=Ω Again using Equation (14.20), we have 11100111110.0170.11090.101110111.01710.11091if R ++=+⋅=+++ so that 99.1 if R =Ω b. To determine 0:f RFor the first op-amp, we can write, using Equation (14.36) 020101111100401111||10||L f i A R R R R R ⎡⎤⎡⎤⎢⎥⎢⎥⎢⎥⎢⎥=⋅=⋅⎢⎥⎢⎥++⎢⎥⎢⎥⎣⎦⎣⎦ which yields010.021 k f R =Ω For the second op-amp, then020*******()||11000.1011(0.121)||10L f f i A R R R R R R ⎡⎤⎢⎥⎢⎥=⋅⎢⎥+⎢⎥+⎣⎦⎡⎤⎢⎥⎢⎥=⋅⎢⎥+⎢⎥⎣⎦ or018.4 f R =Ω c. To find the gain, consider the second op-amp.0122202()0.10.1d d d i v v v v v R −−−−+= (1) 010221110.10.1100.10.1d v v v ⎛⎞+++=−⎜⎟⎝⎠ or 01202(10)(20.1)(10)d v v v +=−02020220()00.1L d d v A v v v R −−−+= (2) 0202202210010110.10.1(11)(90)0d d v v v v v ⎛⎞−−+⎜⎟⎝⎠−==−or 202(0.1222)d v v = Then Equation (1) becomes010202(10)(0.1222)(20.1)(10)v v v += or0102(1.246)v v =− Now consider the first op-amp.1110()11I d d d i v v v v v R −−−−+=1 (1) 10111(1)(1)1101I d v v v ⎛⎞+++=−⎜⎟⎝⎠1(1)(2.1)(1)v v v +=− or101I d 010*******()00.11091L d d v v A v v v R −−−++= (2) 011011111100100.11091111(11.017)(99)0d d v v v v ⎛⎞⎛++−−=⎜⎟⎜⎝⎠⎝−=⎞⎟⎠−or 101(0.1113)d v v = Then Equation (1) becomes0101(1)(0.1113)(2.1)I v v v += or01(1.234)I v v =− We had0102(1.246)v v =− So02(1.246)(1.234)I v v = or 020.650I v v =d. Ideal021Iv v = So ratio of actual to ideal0.650.=______________________________________________________________________________________14.18(a) For the op-amp. 60310L dB A f ⋅= 6341050 Hz 210dB f ==× For the closed-loop amplifier. 631040 kHz 25dB f == (b) Open-loop amplifier.444310A f f ==×=10 Closed-loop amplifier330.2524.255dB dB f f f f −===⇒______________________________________________________________________________________14.19dB,100=o A 510=⇒o A dB,38=A 43.79=A Then 2451011043.79⎟⎟⎠⎞⎜⎜⎝⎛+=PD f 94.743.79101054=⇒≅PD PD f f Hz Hz()()551094.794.710×==GBW ______________________________________________________________________________________14.20(a) 11151501112=⎟⎠⎞⎜⎝⎛+=⎟⎟⎠⎞⎜⎜⎝⎛+=R R A CLO kHz()10911102.1336=⇒=×=−−dB dB T f f f (b) ()()()()⎥⎦⎤⎢⎣⎡±±+=05.011505.011501CLO A ()05.1225.145.1571max =+=CLO A ()05.1075.155.1421min =+=CLO A Then05.1205.10≤≤CLO AkHz ()6.9905.12102.1336=⇒=×=−−dB dB T f f f kHz()4.11905.10102.1336=⇒=×=−−dB dB T f f f Then kHz4.1196.993≤≤−dB f ______________________________________________________________________________________14.21The open loop gain can be written as 006()11510L PD A A f f f j j f =⎛⎞⎛⎞+⋅+⋅⎜⎟⎜⎟×⎝⎠⎝⎠ where 50210.A =× The closed-loop response is 001L CL LA A A β=+ At low frequency, 552101001(210β×=+×) So that39.99510.β−=× Assuming the second pole is the same for both the open-loop and closed-loop, then116tan tan 510PD f f f φ−−⎛⎞⎛⎞=−−⎜⎟⎜⎟×⎝⎠⎝⎠ For a phase margin of80 ,°100.φ=−°So 1610090tan 510f −⎛⎞−=−−⎜⎟×⎝⎠ or58.81610 Hz f =× Then051L A == or 558.81610 1.969610PD f ×≅× or 4.48 HzPD f = ______________________________________________________________________________________14.22(a) 1st stage33(10) 1 100dB dB f MHz f kHz −−=⇒= 2nd stage33(50) 1 20dB dB f MHz f kHz −−=⇒= Bandwidth of overall system20 kHz ≅(b) If each stage has the same gain, so 250022.36K K =⇒= Then bandwidth of each stage33(22.36) 1 44.7dB dB f MHz f kHz −−=⇒= ______________________________________________________________________________________14.23(a) 9978.91051110.101141212−=×+−=⎟⎠⎞⎜⎝⎛++−=O CLO A R R R R A kHz()033.1509978.9105.1336=⇒=×=−−dB dB T f f f (b) ()34.9999978.93−=−=CLO A At ; dB f −364.706234.999==⇒CL AThen 323310033.150134.99964.706⎥⎥⎦⎤⎢⎢⎣⎡⎟⎟⎠⎞⎜⎜⎝⎛×+=−dB f 49.7664.70634.99910033.1501323233=⇒⎟⎠⎞⎜⎝⎛=⎥⎥⎦⎤⎢⎢⎣⎡⎟⎟⎠⎞⎜⎜⎝⎛×+−−dB dB f f kHz ______________________________________________________________________________________14.24466333(510)1020 (25)1040 1PD PD dB dB vov v dB f f Hzf f kHzA A A fj f −−−×=⇒=⇒==⇒=+ At 30.520 dB f f k −==Hz22.36v AAt 3280 dB f f k −==Hz11.18v A = ______________________________________________________________________________________14.25 36(2010)1050vf vf MAX MAX A A ×⋅=⇒= ______________________________________________________________________________________14.26(a) ()159521052max 6max =⇒×==f V SR f PO ππkHz (b) ()5.5305.12105max 6max =⇒×=f f πkHz (c) ()99.14.02105max 6max =⇒×=f f πMHz ______________________________________________________________________________________14.27a. Using Equation (14.55), 6038102(25010)P V π×=× or 0 5.09 V P V =b.Period 6311410 s 25010T f −===××One-fourth period 1 sμ= 00Slope 8 V/s 18 VP P V SR s V μμ===⇒= ______________________________________________________________________________________14.28 PO V SR f π2max = V/s()()531054.71012102×=×=πSR Or V/754.0=SR μs______________________________________________________________________________________14.29(a) 0.521063.0102063max =⇒×=×=PO POV V f πV (b) ()87.231020210336=××=πPO V V ______________________________________________________________________________________14.30For input (a), maximum output is 5 V. 1 V/μs S R =soFor input (b), maximum output is 2 V.For input (c), maximum output is 0.5 V so the output is______________________________________________________________________________________14.31 For input (a),01max 3 V.v =Then02max 3(3)9 V v ==For input (b),01max 1.5 V.v =Then()02max 31.5 4.5V v ==______________________________________________________________________________________14.32111exp ,BE S T V I I V ⎛⎞=⎜⎟⎝⎠ 222exp BE S T V I I V ⎛⎞=⎜⎟⎝⎠ Want so12,I I = 1411214212510(1)exp 1510(1)exp (1)exp (1)BE T BE T BE BE T V x V I I V x V V V x x V −−⎛⎞×+⎜⎟⎝⎠==⎛⎞×−⎜⎟⎝⎠⎛⎞−+=⎜⎟−⎝⎠Or 211exp exp 10.0025exp 1.100.026OS BE BE T T V V V x x V ⎛⎞⎛−+==⎜⎟⎜−⎝⎠⎝⎛⎞==⎜⎟⎝⎠V ⎞⎟⎠Now 1(1)(1.10)x x +=−⇒ 0.0476 4.76%x =⇒______________________________________________________________________________________14.33(a) Balanced circuit, A154105−×=S I (b) From Eq. (14.62), 51=CE υV, 4.42.16.52=−=CE υV⎟⎠⎞⎜⎝⎛+⎟⎠⎞⎜⎝⎛+⋅=++802.111204.41806.011205143S S I I()()015.1036667.10075.1041667.143⋅=S S I I 1544310939.40123.1−×=⇒=S S S I I I A (c) 51=CE υV, 1.35.26.52=−=CE υV ⎟⎠⎞⎜⎝⎛+⎟⎠⎞⎜⎝⎛+⋅=++805.211201.31806.011205143S S I I()()03125.1025833.10075.1041667.143⋅=S S I I 1544310811.403937.1−×=⇒=S S S I I I A ______________________________________________________________________________________14.34μ150=n K A/V 2()()μx x x K n 30011501150=−−+=ΔA/V2 ⎟⎟⎠⎞⎜⎜⎝⎛Δ=n n n Q OS K K K I V 221()01837.08165.015030015022002110153=⇒=⎟⎠⎞⎜⎝⎛=×−x x x ______________________________________________________________________________________14.35(a) V()()3310603001021030−−×±−=×±−=O υ So 240.0360.0−≤≤−O υV (b) V()06.0310*******±−=×±−=−O υ So 94.206.3−≤≤−O υ V______________________________________________________________________________________14.36()2sin 2530±−=t O ωυmV06.0sin 75.0±−=t O ωυVSo ()(06.0sin 75.006.0sin 75.0)+−≤≤−−t t O ωυω V______________________________________________________________________________________14.373840.510510 10I A −−×==×Also 01i o o dV I I C V Idt t dt C C =⇒==∫⋅Then 836510511010t t s −−×=⇒=×0______________________________________________________________________________________14.38(a) (31010011±⎟⎠⎞⎜⎝⎛+=O υ) mV, 33331≤≤−O υmV ()33310502±±⎟⎠⎞⎜⎝⎛−=O υ mV, 1801802≤≤−O υmV (b) ()()310111±=O υ mV, 143771≤≤⇒O υmV()730314352−=+−=O υmV()37037752−=−−=O υmVSo 37.073.02−≤≤−O υV(c) ()()3100111±=O υ mV133.1067.11≤≤O υV()68.5003.0133.152−=+−=O υV()32.5003.0067.152−=−−=O υVSo 32.568.52−≤≤−O υV______________________________________________________________________________________14.39 due to 0v I v 01(0.5)10.9545 V 1.1v ⎛⎞=+=⎜⎟⎝⎠ Wiper arm at (using superposition) 10 V,V +=151154||0.0909(10)(10)||0.0909100.090R R v R R R ⎛⎞⎛⎞==⎜⎟⎜⎟++⎝⎠⎝⎠= Then 011(0.090)0.0901v ⎛⎞=−=−⎜⎟⎝⎠Wiper arm in center, and10v =020v = Wiper arm at10 V,V −=−10.090v =− So030.090v = Finally, total output (from superposition)0:v Wiper arm at,V + 00.8645 Vv = Wiper arm in center, 00.9545 V v = Wiper arm at,V − 0 1.0445 V v = ______________________________________________________________________________________14.40 a.120.5||250.490 k R R ′′===Ω or 12490 R R ′′==Ωb. From Equation (14.75), 6114621412510(0.026) ln (0.125)21012510(0.026) ln (0.125)2.210R R −−−−⎛⎞×′+⎜⎟×⎝⎠⎛⎞×′=+⎜⎟×⎝⎠12210.586452(0.125)0.583974(0.125)0.002478(0.125)()R R R R ′′+=+′′=−So210.0198 k 19.8 R R ′′−=Ω⇒Ω Then 2121(1)0.0198(1)(0.5)(1)(50)(0.5)(50)0.0198(0.5)(1)(50)(0.5)(50)25(1)250.019850.5500.550(0.550)(2525)(25)(50.550)0.0198(50.550)(0.550)x x x xR x R R R R x R R xR x x x x x x x xx x x x x x −×−=+−+−−=+−+−−=−++−−−=−+{}{}{}{}22222250.50.5505050.5500.019825.252525252500250.50.019825.25250025000.50.019998 1.98 1.981.98 2.980.4802x x x x x x x x x x x x x x x x x −+−−+=+−−−=+−−=+−−+==So 0.183x = and 10.81x −=7ΩΩ ______________________________________________________________________________________14.411122||150.5||150.4839 k ||350.5||350.4930 k R R R R ′===′=== From Equation (14.75), 121122341221121112222211222(0.026) ln (0.026) ln (0.026) ln (0.026) ln 1(0.026) ln (0.4930)1(0.9815)C C C C S S C C C C C C C C C C C C C C i i i R i R I I i i R i R i i i R i R i i R i i i i i ⎛⎞⎛⎞′′+=+⎜⎟⎜⎟⎝⎠⎝⎠⎛⎞′′=−⎜⎟⎝⎠′⎛⎞⎡⎤′=−⋅⎜⎟⎢⎥′⎝⎠⎣⎦⎛⎞=−⎜⎟⎝⎠⎡⎤⎛⎞⎢⎥⎜⎟⎝⎠⎣⎦ By trial and error: 1252 A C i μ= and 2248 A C i μ=or 12 1.0155C C i i = ______________________________________________________________________________________14.42(a) ()()()2.010********=×=−A O μυV Insert resistor3R ()()09.92020011022.03362=⇒⎟⎠⎞⎜⎝⎛+×−=−=−R R A O μυk Ω (b) ()()()16.010200108.0368.0=××=−A O μυV ()()09.29202001105.016.03365.0=⇒⎟⎠⎞⎜⎝⎛+×−=−=−R R A O μυk Ω ______________________________________________________________________________________14.43(a) V ()()3.010*********−=××−=−=−R I B O υ(b) ()5.03.002.015150−=−−=O υV (c) ()1.03.002.015150−=−−−=O υV (d) ()3.13.01.015150−=−−=O υV ______________________________________________________________________________________14.44(a) V ()()15.010250106.036=××=−O υ(b) ()()478.015.0008.041=+=O υV(c) ()()0065.015.00035.041=+−=O υV(d) ()()15.0sin 205.015.0sin 005.041+=+=t t O ωωυ (V)______________________________________________________________________________________14.45a.For 2 1 A,B I μ= then()(6401010v −=−) or00.010 Vv =− b. If a 10 resistor is included in the feedback loop k ΩNow021(10)(10)0B B v I I =−+= Circuit is compensated if12.B B I I =______________________________________________________________________________________14.46From Equation (14.83), we haveΩ 020S v R I = where and 240 k R =0 3 A.S I μ= Then()(3604010310v −=××) or 00.12 V v = ______________________________________________________________________________________14.47a. Assume all bias currents are in the same direction and into each op-amp.()()()6501101100 k 10100.1 V B v I v −=Ω=⇒=Then ()()()()()(020******* k 0.15105100.50.05B v v I −=−+Ω=−+×=−+)or 020.45 V v =− b. Connect resistor to noninverting terminal of first op-amp, and310||1009.09 k R ==ΩΩ resistor to noninverting terminal of second op-amp.310||508.33 k R ==______________________________________________________________________________________14.48a. For a constant current through a capacitor. 001 t v I C =∫dt or 60060.110(0.1)10v t v −−×=⋅⇒=t b.At10 s,t =0 1 V v = c. Then 1240010010(10)10v t v −−−×=⋅⇒=t At10 s,t =0 1 mV v = ______________________________________________________________________________________14.49(a) V()()15.010********=××=−O υ 15.02=O υV ()()()09.010*******.02020363−=××+−=−O υV (b) 33.85010==A R k Ω 102020==B R k Ω(c) V()()015.0103.01050631±=××±=−O υ 015.02±=O υVV()()021.0015.0103.01020633±=±××±=−O υ______________________________________________________________________________________14.50a. Using Equation (14.79),Circuit (a),()()()()63630500.81050100.8102510150v −−⎛⎞=××−××+⎜⎟⎝⎠ or 00v = Circuit (b),()()()()636302500.81050100.81010150410 1.6v −−−⎛⎞=××−×+⎜⎟⎝⎠=×− or 0 1.56 V v =− b. Assume 10.7 AB I μ= and 20.9 A,B I μ= then using Equation (14.79): Circuit (a),()()()()63630500.71050100.91025101500.0350.045v −−⎛⎞=××−××+⎜⎟⎝⎠=− or00.010 V v =−Circuit (b), ()()()()63660500.71050100.910101500.035 1.8v −−⎛⎞=××−×+⎜⎟⎝⎠=− or 0 1.765 Vv =−______________________________________________________________________________________14.51(a) For : OS V ()333101001±=±⎟⎠⎞⎜⎝⎛+=O υmV For : B I ()()()043.010*******.0max 36=××=−O υ V()()()037.010*******.0max 36=××=−OυVSo 764≤≤O υmV(b) For : OS V 33±=O υmV For : VOS I ()()006.010*******.036±=××±=−O υSo 3939≤≤−O υmV(c) ()039.02.0101001±⎟⎠⎞⎜⎝⎛+=O υ So 239.2161.2≤≤O υV______________________________________________________________________________________14.52a. 2(15)0.010 V i i R R R ⎛⎞=⎜⎟+⎝⎠ 22150.00066671515(10.0006667)0.0006667 R R =+−= Then 222.48 M R =Ωb.11||15||10 6 k i F R R R R ==⇒=Ω ______________________________________________________________________________________14.53a. Assume the offset voltage polarities are such as to produce the worst case values, but the bias currents are in the same direction.Use superposition:Offset voltages 010********||1(10)110 mV ||1050||(5)(110)1(10)10||610 mV v v v v ⎛⎞=+==⎜⎟⎝⎠⎛⎞=++⎜⎟⎝⎠⇒=Bias Currents: 6301(100 k )(210)(10010)0.2 V B v I −=Ω=××= Then6302(5)(0.2)(210)(5010)0.9 V v −=−+××=− Worst case: is positive and is negative, then01v 02v 010.31 V v = and 021.51 V v =−b. Compensation network:If we want20 mV and 10 V 8.33(10)0.0208.33B B C C R V V R R R ++⎛⎞==⎜⎟+⎝⎠⎛⎞=⎜⎟+⎝⎠ or 4.15 M C R ≅Ω______________________________________________________________________________________14.54(a) Offset voltage: ()122105011±=±⎟⎠⎞⎜⎝⎛+=O υmV 142122±=±±=O υmV ()()()16221220203±=±+±⎟⎠⎞⎜⎝⎛−=O υmV Bias current:V()()0105.010501021.0361=××=−O υ or V ()()0095.010501019.0361=××=−O υ 12O O υυ= ()()()()0042.010201021.0113613+−=××+−=−O O O υυυor()()0038.010201019.013613+−=××+−=−O O O υυυ By superposition5.225.21≤≤−O υmV5.245.42≤≤−O υmV7.103.223≤≤−O υmV(b) Bias currents:()()()110501002.010*******±=⇒××±=×±=−O OS O I υυmV()()()4.010201002.010*******±=⇒××±=×±=−O OS O I υυmVBy superposition: ()4.02213±±±=O O υυ13131≤≤−O υmV15152≤≤−O υmV4.174.173≤≤−O υmV______________________________________________________________________________________14.55For circuit (a), effect of bias current:390(5010)(10010) 5 mV v −=××⇒ Effect of offset voltage 050(2)1 4 mV 50v ⎛⎞=+=⎜⎟⎝⎠ So net output voltage is09 mV v = For circuit (b), effect of bias current:Let then from Equation (14.79),2550 nA,B I =1450 nA,B I = 93960250(45010)(5010)(55010)(10)1502.2510 1.1v −−−⎛⎞=××−×+⎜⎟⎝⎠=×− or0 1.0775 V v =− If the offset voltage is negative, then0(2)(2)4mV v =−=− So the net output voltage is 0 1.0815 Vv =− _____________________________________________________________________________________14.56a. At so the output voltage for each circuit is25C,T =°0 2 mV S V = 0 4 mV v = b. Forthe offset voltage for is 50C,T =° 0 2 mV (0.0067)(25) 2.1675 mV S V =+= so the output voltage for each circuit is 0 4.335 mVv = ______________________________________________________________________________________14.57 a. At then25C,T =°0 1 mV,S V = 010150(1)1 6 mV 10v v ⎛⎞=+⇒=⎜⎟⎝⎠and 020********(1)120206(4)(1)(4)28 mV v v v ⎛⎞⎛⎞=+++⎜⎟⎜⎟⎝⎠⎝⎠=+⇒= b. Atthen 50C,T =°01(0.0033)(25) 1.0825 mV,S V =+= 0101(1.0825)(6) 6.495 mV v v =⇒=and 02(6.495)(4)(1.0825)(4)v =+ or 0230.31 mVv = ______________________________________________________________________________________14.580025C;500 nA,200 nA50C,500 nA (8 nA /C)(25C)700 nA200 nA (2 nA /C)(25C)250 nA B S B S I I I I °==°=+°°==+°°= a. Circuit (a): For ,B I bias current cancellation, 00v =Circuit (b): For ,B I Equation (14.79), 93960050(50010)(5010)(50010)(10)1500.025 1.000.975 V v v −−⎛⎞=××−×+⎜⎟⎝⎠=−⇒=− b. Due to offset bias currents.Circuit (a): 930(20010)(5010)0.010 V v −=××⇒=0vCircuit (b): 21Let 600 nA400 nA B B I I == Then93960050(40010)(5010)(60010)(10)1500.020 1.20 1.18 V v v −−⎛⎞=××−×+⎜⎟⎝⎠=−⇒=−c. Circuit (a): Due to ,B I 0v = Circuit (b): Due to ,B I93960050(70010)(5010)(70010)(10)1500.035 1.40 1.365 V v v −−⎛⎞=××−×+⎜⎟⎝⎠=−⇒=−Circuit (a): Due to 0,S I930(25010)(5010)0.0125 V v v −=××⇒=0Circuit (b): Due to0,S I 21Let 825 nA575 nA B B I I == Then 93960050(57510)(5010)(82510)(10)1500.02875 1.65 1.62 Vv v −−⎛⎞=××−×+⎜⎟⎝⎠=−⇒=− ______________________________________________________________________________________14.590025C; 2 A,0.2 A 50C, 2 A (0.020 A /C)(25C 2.5 A 0.2 A (0.005 A /C)(25C)0.325 A B S B S I I I )I μμμμμμμμ°==°=+°°==+°°= a. Due to :B I (Assume bias currents into op-amp). 630101(50 k )(210)(5010)0.10 VB v I v −=Ω=××⇒= 020*********(60 k )(50 k )12020(0.1)(4)(210)(6010)(210)(6010)4B B v v I I −−⎛⎞⎛⎞=++Ω−Ω+⎜⎟⎜⎟⎝⎠⎝⎠=+××−××3 or020.12 V v = b. Due to0:S I1121st op-amp. Let 2.1 A2nd op-amp. Let 2.1 A1.9 A B B B I I I μμμ===6301101(50 k )(2.110)(5010)0.105 V B v I v −=Ω=××⇒= 020112636360601(60 k )(50 k )12020(0.105)(4)(2.110)(6010)(1.910)(5010)(4)B B v v I I −−⎛⎞⎛⎞=++Ω−Ω+⎜⎟⎜⎟⎝⎠⎝⎠=+××−×× or 020.166 V v =c. Due to :B I 63010101026363(2.510)(5010)0.125 V60601(60 k )(50 k )12020(0.125)(4)(2.510)(6010)(2.510)(5010(4)B B v v v v I I −−=××⇒=⎛⎞⎛⎞=++Ω−Ω+⎜⎟⎜⎟⎝⎠⎝⎠=+××−×× or 020.15 V v =Due to0:S I12Let 2.625 A2.3375 A B B I I μμ== 6301101(50 k )(2.662510)(5010)1.133 V B v I v −=Ω=××⇒= 020112636360601(60 k )(50 k )12020(0.133)(4)(2.662510)(6010)(2.337510)(5010)(4)B B v v I I −−⎛⎞⎛⎞=++Ω−Ω+⎜⎟⎜⎟⎝⎠⎝⎠=+××−×× or 020.224 Vv = ______________________________________________________________________________________14.60(a) 0.51050==d A For common-mode, 21I I υυ=From Chapter 9, 12431211R R R R R R A cm −⎟⎟⎠⎞⎜⎜⎝⎛+⎟⎟⎠⎞⎜⎜⎝⎛+= If , ()75.50015.1502==R ()85.9015.01101=−=R, ()85.9015.01103=−=R ()75.50015.1504==R Then 610046.515228.519409.115228.685.975.5075.5085.9185.975.501−×=−=−++=cm A If , ()15.10015.1103==R ()25.49015.01504=−=R Then 051268.015228.520609.115228.685.975.5025.4915.10185.975.501−=−=−++=cm A If , 25.492=R 15.101=R Then 04877.085222.419409.185222.515.1025.4975.5085.9115.1025.491+=−=−++=cm A Now ()8.39051268.05log 20min 10=⎟⎠⎞⎜⎝⎛=dB CMRR dB (b) , ()5.5103.1502==R ()70.997.0101==R, ()5.4897.0504==R ()3.1003.1103==R。

电容层析成像系统传感器场域剖分及参数优化

哈尔滨理工大学学报JOURNAL OF HARBIN UNIVERSITY OF SCIENCE AND TECHNOLOGY第26卷第2期2021年4月Vol. 26 No. 2Apr. 2021电容层析成像系统传感器场域剖分及参数优化张晋荣，王莉莉，杨博韬，刘笑（哈尔滨理工大学计算机科学与技术学院，哈尔滨150080）摘要：分析电容层析成像系统的组成结构和电容传感器的数学模型，采用有限元法对传感器的敏感场进行仿真，并根据敏感场的分布特点，提出一种将三角形剖分与四边形剖分相结合的方法，完成了敏感场的剖分以及数值计算。

在综合考虑敏感场分布的均匀性、传感器的灵敏程度以及测量电路的量程范围要求等性能指标的条件下，确定了传感器的优化设计函数。

采用正交设计法对传感器的结构参数进行优化试验，应用RBF 神经网络对正交设计的试验结果进行回归分析，并基于改进后的粒子群算法进行寻优，采用优化后的结构参数完成了对电容传感器的优化设计。

由实验结果的对比分析可知，正交试验设计的传感器重建图像的精度高于基准传感器的重建精度，而采用RBF 神经网络与混沌模拟退火粒子群算法优化的传感器成像效果优于正交试验设计的结果，为获得灵敏度高且可靠性强的电容传感器提供了一种新的优化途径。

关键词：电容层析成像；传感器；有限元分析;RBF 神经网络；混沌模拟退火粒子群算法DOI ：10.15938/j. jhust. 2021.02.008中图分类号：TP216文献标志码：A 文章编号：1007-2683(2021 )02-0059-09Sensor Field Segmentation and Parameter Optimizationfor Electrical Capacitanee Tomography SystemZHANG Jin-rong, WANG Li-li, YANG Bo-Tao , LIU Xiao(School of Computer Science and Technology , Harbin University of Science and Technology , Harbin 150080,China)Abstract : The composition of the capacitance tomography system and the mathematical model of the capacitivesensor are analyzed ・ The finite element method is used to simulate the sensitive field of the sensor. According to thedistribution characteristics of the sensitive field , a combination of triangular and quadrilateral splitting is proposed ・The method completes the segmentation of the sensitive field and the numerical calculation. The optimal design function of the sensor is determined under the condition that the uniformity of the sensitive field distribution , thesensitivity of the sensor and the range requirement of the measuring circuit are comprehensively considered ・ The orthogonal design method is used to optimize the stmctural parameters of the sensor , and the RBF neural network isused to perform regression analysis on the orthogonal design test results. After the particle swarm optimization algorithm is used for optimization , the optimized design of the capacitive sensor is completed by using the optimizedstructural parameters ・ From the comparative analysis of the experimental results , the accuracy of the reconstructed image of the sensor designed by orthogonal experiment is higher than that of the reference sensor , while the imaging收稿日期：2019 -06 -06基金项目：国家自然科学基金(60572153,60972127)；黑龙江省教育厅计划项目(11541040,12511097 )；黑龙江省青年科学基金(QC2012C059);黑龙江省博士后资助项目(LBH-Z11109).作者简介：张晋荣(1993-),女,硕士研究生；杨博韬(1993-)，男，硕士研究生.通信作者：王莉莉(1980—)，女，博士，教授，硕士研究生导师,E-mail : wanglili@ hrbust. edu. cn.60哈尔滨理工大学学报第26卷effect of the sensor optimized by RBF neural network and chaotic simulated annealing particle swarm optimization algorithm is better than the orthogonal experimental design・The results of the experimental design provide a new optimization approach for obtaining capacitive sensors with high sensitivity and reliability.Keywords:electrical capacitance tomography；sensor；finite element analysis；RBF neural network；chaotic simulated annealing particle swarm algorithm0引言电容层析成像(electrical capacitance tomography,ECT)技术是自20世纪80年代借鉴医学CT技术发展起来的一种成本低廉且安全性能高的新型流动层析成像技术⑴，因其具有结构简单、响应速度快等诸多优点，被广泛应用于工业管道中两相流或多相流的测量过程中。

温度响应型酰腙可逆共价键水凝胶的制备及性能

Vol. 35 No. 1功能高分子学报2022 年 2 月Journal of Functional Polymers93文章编号： 1008-9357(2022)01-0093-08DOI: 10.14133/ki.1008-9357.20210322002温度响应型酰腙可逆共价键水凝胶的制备及性能何元1，罗媛媛2，刘通1，张银山1，郭赞如1，章家立1（1. 华东交通大学材料科学与工程学院，高分子材料与工程系，南昌 330013；2. 重庆市计量质量检测研究院，重庆 401120）摘要：首先，通过可逆加成-断裂转移（RAFT）聚合制备了丙烯酰胺（AM）、双丙酮丙烯酰胺（DAAM）和N-异丙基丙烯酰胺（NIPAM）的共聚物（PAM-co-PDAAM-co-PNIPAM）；然后，使PAM-co-PDAAM-co-PNIPAM与己二酸二酰肼（ADH）反应后，得到了具有温度和pH双重响应性的水凝胶。

通过核磁共振氢谱（1H-NMR）和凝胶渗透色谱（GPC）、流变仪、扫描电镜（SEM）以及傅里叶变换红外光谱（FT-IR）对共聚物和水凝胶的结构和组成，以及水凝胶的温度和pH双重响应行为进行了研究。

研究表明，该水凝胶具有温度调控的自愈合性，对药物阿霉素（Dox）表现出pH和温度双重响应的可控释放行为。

关键词：智能水凝胶；酰腙可逆共价键；自愈合；温度响应中图分类号： O633 文献标志码： APreparation and Properties of Temperature-Responsive HydrogelsBased on Acylhydrazone Reversible Covalent BondsAll Rights Reserved.HE Yuan1, LUO Yuanyuan2, LIU Tong1, ZHANG Yinshan1, GUO Zanru1, ZHANG Jiali1（1. Department of Polymer Materials and Engineering, School of Materials Science and Engineering, East China JiaotongUniversity, Nanchang 330013, China; 2. Chongqing Academy of Metrology andQuality Inspection, Chongqing 401120, China）Abstract: A series of PAM-co-PDAAM-co-PNIPAM copolymers were synthesized by reversible addition fracture transfer(RAFT) polymerization from acrylamide (AM), diacetone acrylamide (DAAM) and N-isopropylacrylamide (NIPAM). Theirstructure and composition were characterized by Nuclear Magnetic Resonance (NMR) and Gel Permeation Chromatography(GPC). Hydrogel with pH and temperature dual-response formed by the acyl hydrazone dynamic bonds between ketocarbonylin polymer and hydrazide in adipic dihydrazide (ADH). The dual-responsive behavior of hydrogels to temperature and pHwas researched by rheological measurement, Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FT-IR)spectroscopy. At the same time, the hydrogel demonstrated temperature controlled self-healing properties. Besides, thehydrogels showed pH-and temperature-responsive controlled release behaviors for doxorubicin(Dox).Key words: smart gel； acylhydrazone dynamic covalent bond； self-healing； temperature response收稿日期： 2021-03-22基金项目：国家自然科学基金（21802041，51563009，21865009）；江西省杰出青年基金（20202ACBL214001）作者简介：何元（1994—），男，硕士，主要研究方向为功能高分子材料。

第四章均聚物——共聚物

两嵌段的SI（MnI ＝11.7×103）与PI （MnI＝9.1 ×103 ）的共混物显示出宏观尺度上均一的状态，在电镜照片表现出PI微区明显扩大，表明PI溶入了共聚物中。当把PI 的分子量增加到 MnI=17.5 ×103时，就出现了相分离，这和日本人研究的结果相一致。
三嵌段的SIS，情况有所不同。当均聚物PI的分子量降至SIS中PI分子量的1/2时，仍出现共聚物和均聚物之间的宏观相分离，只有当均聚物的分子量为共聚物SIS中PI分子量的1/4时，才能观察到 PI微区增大的宏观均一体系。表明三嵌段共聚物的中央嵌段与均聚物间的相容性远较二嵌段共聚物为小。
综合以上实验结果可见，对某种类型的嵌段共聚物来说，都存在一临界的MH/MB范围，若实际的比值大于该值，体系不相容，反之则相容。对于二嵌段、三嵌段和四臂星形共聚物，该临界值相差很大，分别约为：1，1/2，1/4。令我们感兴趣的并非这三个数据本身，因为共聚物的总分子量、组成、成膜条件等都可能对相容性有影响。但在同样的实验条件下得到的共聚物嵌段和相应均聚物的相容性按二嵌段——三嵌段——四臂星形的序列递减。
在以上Eastmond等的实验中，用于共混的均聚物A就是制备ABCP的预聚物A。因此它们的分子量是相等的。也就是说，他们作出的关于Cop/Homo不相容的结论是在共聚物和均聚物的分子量相等的条件下得到的，这显然就与日本人的结论完全不同。
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4.2 大分子构造的影响
---结论：嵌段共聚物与相应均聚物的相容形变化应按四臂星形——三嵌段——二嵌段递增。
共聚物的嵌段和相应的均聚物，虽然在化学结构上是等同的，混合时几乎没有能量的变化，但是它们之间的相互溶解却不是无条件的，若嵌段在形成微区时采取了不利的构象，因而在混合时会有构象熵的损失（ΔS减小）。因此，相容性随分子量的“组合”的变化自然应该与共聚物的大分子构造有关。

【材料】加州大学伯克利分校张翔综述：二维磁性晶体及新兴异质结器件

【材料】加州大学伯克利分校张翔综述：二维磁性晶体及新兴异质结器件加州大学伯克利分校张翔教授Science 综述：二维磁性晶体及新兴的异质结器件【引言】几个世纪以来，人类探索磁性及其相关现象的脚步从未停歇。

磁石对铁的神奇吸引力以及鸟、鱼或昆虫在相隔数千英里的目的地之间的导航能力，在电磁学和量子力学发展的早期，很难想象这些有趣的现象具有相同的磁性起源。

磁性来源于基本粒子的运动电荷与自旋，因此，它和电子一样普遍存在。

磁性在生物活体及能量收集、数据存储和医学诊断中都具有广泛的应用。

当无穷小的“电子磁体”自发对齐时，磁序就构成物质的基本相位，就可制备出很多功能性装置，例如发电机和电动机、磁阻存储器和光学阻隔器等。

如果能在原子层厚的平台上产生这种磁序，将为集成化的、柔性的以及生物兼容性的器件提供巨大的应用潜力，然而，由于自身的局限，这样的二维磁体并不容易获得。

【成果简介】近日，加州大学伯克利分校张翔教授（通讯作者）等人综述了二维（2D）磁性晶体及其异质结的研究进展并且展望了这种材料可能在信息领域获得应用。

近年来发现的2D 磁性范德瓦尔斯晶体为理解 2D 磁性提供了理想的平台，通过控制 2D 磁性可以促进原子层厚的、柔性磁光和电磁器件（如磁阻存储器和自旋场效应晶体管）的实际应用。

2D 磁体与不同的电子和光子材料之间的无缝化集成为实现单一材料前所未有的性能和功能开辟了一条崭新的途径。

该论文回顾了这一领域的研究进展，并确定了器件应用的可能方向，同时有望引起自旋电子学、传感器和计算机等领域的进一步突破。

该综述以题为“Two-dimensional magnetic crystals and emergent heterostructure devices”发表于国际顶尖期刊Science。

【图文导读】图一不同维度铁磁体的基本物理参数和自旋激发（A、B）在共线磁体中，交换相互作用与磁的各向异性是基本参数；交换相互作用由电子的反对称波函数引起并且在鲍利不相容原理下受库伦相互作用的约束，自旋之间的交换相互作用可以直接建立（红色虚线1）或由传导电子（带有虚线标记2 的绿色球）或中间阴离子（带有虚线标记3 的橙色球）间接介导；当自旋对齐时，通常存在一个择优取向，即为磁各向异性；磁各向异性有很多来源，例如磁晶各向异性、形状各向异性和应力各向异性等（C-F）在 2D 各向同性的海森堡铁磁体中，由于自旋波激发间隙的缺失、磁子态密度的突然出现以及零能量下发散的波色-爱因斯坦统计等原因，磁子将在非零温度下发生大规模的激发，其结果是长程磁序的崩溃；单轴磁各向异性（UMA）打开了自旋波激发间隙，从而抵抗了磁子的热扰动，导致有限的居里温度；随着系统从2D 发展到 3D，磁子 DOS 谱在激发阈值处由阶跃函数逐渐增大为零；因此，在 3D 系统中，UMA 不是存在有限温度长程磁序的先决条件图二非磁性2D 材料中诱导磁性的示意图（A）Ar + 辐照石墨烯所生成碳空位的STM 形貌图，比例尺为5 nm（B）由单个氢原子修饰的石墨烯局部磁矩示意图（中间的白色小球），同样的自旋-极化态在相同亚晶格的碳位上扩展了几纳米，但相反的自旋-极化态占据了另外的碳位亚晶格（C）磁化与磁场平行于氟化石墨烯的平面，点是实验数据，实线是基于布里渊区函数的拟合曲线，在液氦温度下，氟化石墨烯和具有空位缺陷的石墨烯均未发现铁磁性（D）在磁绝缘体YIG 上制备的石墨烯场效应晶体管的示意图（E）覆盖有一层沉积的磁性绝缘体 EuS 薄膜的石墨烯场效应晶体管的示意图，非磁性2D 材料可以通过接触磁性材料而获得磁性（F）在电偏置Bernal 堆垛双层石墨烯中计算墨西哥帽的带分散，存在于墨西哥帽边缘的发散电子 DOS 可能导致铁磁斯托纳的不稳定性图三具有代表性的 2D 磁性晶体（A-C）在 SiO 2 /Si 上剥离的少层 Cr 2 Ge 2 Te 6 的光学图像、克尔图像和维数效应，比例尺为10 μm（D-E）CrI 3 的原子结构和石墨夹层 2D CrI 3（依赖于厚度）的克尔信号磁滞回线，在 D 中，橘色箭头代表铁磁耦合自旋磁矩；在E 中，红色和蓝色垂直箭头分别代表自旋向上和自旋向下的磁矩（F-G）Fe 3 GeTe 2 的原子结构和 2D Fe 3 GeTe 2 在 Al 2 O 3 薄膜上的依赖于厚度的归一化剩余反常霍尔电阻，其在 Fe 3 GeTe 2 块状晶体在 10-4 mbar 的氧气压力中通过热蒸发铝而制成，然后再进行多次转移与剥离（H-I）通过MBE 生长在HOPG 上的亚单层 VSe 2 以及生长在MoS 2 的大部分单层 VSe 2 的磁滞 STM 图像，比例尺为 20 nm（J-K）通过 MBE 在 GaSe 上生长出的范德瓦尔斯 MnSe 2 的原子结构以及平均单层 MnSe x 的面外磁滞，在 J 中橙色箭头代表铁磁耦合的自旋磁矩，在K 中，红色和蓝色曲线分别代表当磁场从正扫到负，再由负扫到正时磁滞回线的半支图四 2D 磁体的界面工程（A）电荷迁移和界面的偶极子，橙色球和红色球分别代表电子和空穴（B）界面杂化，下部的绿条表示2D 磁体，上部的深绿条表示异种材料，哑铃代表两种材料的电子轨道，重叠于界面处形成杂化（C）应变效应，下部的实心条表示与不异种材料接触的拉伸 2D磁体，下部虚线表示未受应力的 2D 磁体且未与材料顶部接触（D）额外的超交换相互作用，带箭头的橙色圆圈表示相邻材料的元素，这些元素提供了额外的通道来介导2D 磁体中磁性离子间的超交换相互作用，其由带箭头的红色实心球表示（E）结构扰动，绿色波浪绿带表示2D 磁体，由于与相邻材料接触使结构受到扰动（F）能带重正化，实线表示能带重正化后与相邻材料接触的 2D磁体的电、磁或声子的带分散，虚线表示能带重正化前未接触相邻材料的相同的带分散（G）介电屏蔽，带有箭头的红球表示 2D 磁体中的交换耦合电子，橙色曲线是连接电子的电场线，介电常数ε 越高表明环境对库伦相互作用的屏蔽越大，交换相互作用对库伦相互作用的影响使2D 磁体易受到介电屏蔽（H）自旋-轨道耦合（SOC）近似，通过接触重元素材料，对2D 磁体中的 SOC 进行了有效地改性，从而导致磁性晶体各向异性地变化图五基于 2D 磁体或磁性异质结的自旋电子、磁电子和自旋-轨道电子器件（A-B）基于 Fe 0.25 TaS 2-Ta 2 O 5-Fe 0.25 TaS 2 的 MTJ，铁夹层的TaS 2 具有铁磁性，表面天然氧化物被用作绝缘间隔层；（A）Fe夹层 TaS 2 的原子结构，（B）MTJ 三明治截面的 TEM 图像（C-D）基于石墨-CrI 3-石墨的 MTJ，（C）是 MTJ 示意图，（D）与磁场相关的隧穿电导（E）石墨烯-YIG 异质结的示意图，其可用于基于自旋泵浦的自旋-电荷转换（F）自旋-轨道转矩测量系统的原理图，其核心结构是 WTe 2-坡莫合金异质结，插图是所测试器件的光学图像（G-H）基于双层A-型反铁磁体的自旋场效应晶体管示意图，及其预测的电学性能图六范德瓦尔斯磁体库绿色是块体铁磁范德瓦尔斯晶体，橙色是块体多铁性材料，灰色是从理论上预测的范德瓦尔斯铁磁体，半金属（中间）和多铁性材料（右侧）还未被实验所证实，紫色是α-RuCl 3（近似于Kitaev 量子自旋液体）【小结】最近发现的 2D 磁性晶体为研究强量子限域下自旋集合体的基态、基本激发、动力学等提供了一个理想的平台。

02 Introduction to Materials Science and Engineering

材料科学与工程专业英语
Introduction to Materials Science and Engineering
Microstructure

When describing the structure of a material, we make a clear distinction between its crystal structure and its microstructure. The term“ crystal structure” is used to describe the average positions of atoms within the unit cell(晶胞), and is completely specified by the lattice type （点阵类型）and the fractional coordinates（相对坐标） of the atoms. In other words, the crystal structure describes the appearance of the material on an atomic length scale. The term “microstructure” is used to describe the appearance of the material on the nm-cm length scale. A reasonable working definition of microstructure is “ the arrangement of phases（相） and defects（缺陷） within a material."
2015/9/5
合肥工业大学材料学院

基于相变储能技术的供暖幕墙创新性研究

2021.12科学技术创新基于相变储能技术的供暖幕墙创新性研究田太鹏郭睿桐桂静（辽宁工程技术大学土木工程学院，辽宁阜新123000）我国北方地区由于地理位置及气候特点，在冬季普遍采用区域集中供暖的方式抵抗严寒。

但随着社会的进步，人们物质生活水平不断提高，南方集中供暖的呼声也开始增多。

北方集中供暖的管道设施较为完善，集中供暖所需的经济成本较低，南方大多数城市没有集中供暖的设施基础，重新修建将会耗费大量的人力物力。

如今通过阳光直接加热围护结构从而利用太阳能的方式，由于墙体热容量大，热量传导缓慢，所以利用率不高，很难真正意义上达到节能减排的目的。

Jaffrin A 等[1]人将六水合氯化钙储存在地下加热温室，结果表明在相同温度情况下，相变温室比普通温度温室节省加热燃料。

Kumari [2]等研究了相变材料对被动式热供暖温室大棚的影响，用相变材料和保温材料一体的异质复合墙体板作为日光温室背墙蓄热保温板，利用数值分析方法，研究发现相变材料可以显著提高温室背墙的蓄热性能和保温性能。

国外较早的开始了相变材料应用于日光温室节能蓄热的研究，积累了大量的数据和研究经验，技术较为领先。

管勇[3]等研究了相变蓄热墙体对日光温室热环境的改善，研究表明在不同天气条件下，日光温室北墙内表面采用40mm 厚的相变蓄热墙体材料板。

李晓野[4]、王宏丽[5]等人研究用Na 2HPO 4·12H 2O 作为相变蓄热主体与太阳能集热器相结合，设计制作太阳能集热器，应用日光温室。

国内虽然已有类似研究，但着眼点大多在于日光温室，未提出利用建筑设备实现独立单元供暖的方法。

为解决普通墙体热容量大，用阳光加热围护结构能量利用率不高，且当下相变储能技术大多仅实现了能量的时间转移等问题，本装置提供了一种基于相变储能技术的滚筒式供暖幕墙（如图1所示）。

图1基于相变储能技术的滚筒式供暖幕墙1设计原理1.1设计思路传统供暖一般采用三种形式：集中供暖、地板辐射供暖以及燃气供暖。

微系统技术基础

我国也积极开展了有关研究工作。上海冶金所开展了直径400um的多晶硅齿轮和气动蜗轮以及微静电电机的研究，最近还开始了特殊条件微加速度传感器、光开关的研究。长春光机所对微系统测试技术的研究取得了一定的进展。哈尔滨工业大学研制出的电致升缩陶瓷驱动的二自由度微小型机器人，位移范围为10x10mm 。清华大学精密仪器系试制了多晶硅粱、微流泵与阀、微弹簧等微器件，其热致动微型泵的外形尺寸为 9x6x1mm，输出流量可达40uL/min。上海交通大学开展了直流无刷微电磁电机的研制工作。中国科技大学开展了同步辐射LIGA工艺研究、微观摩擦机理与微润滑技术研究、压电微传感器与驱动器和并行微小加工系统研究。
マイクロ旋盤は、加工精度を損なわずに、大幅な省エネルギー化が可能であることを示しました。そして、産業用ロボットや搬送装置が小型化すればマイクロファクトリが実現できます。マイクロファクトリでは、作る製品に応じて生産機械の配置を簡単に変えられます。また空調に必要なエネルギーも節約できます。ますます小型化する工業製品に対応した21世紀の工場の姿です。
我国的整体形势是面上正逐步铺开，深度也逐步深入，但是总体起步晚，由于技术基础薄弱和资金支持力度小等问题，在研究规模、技术水平上与先进国家相比尚有较大的差距。比如，在一年一度的IEEEMEMS大会上发表论文的数量与欧美日，甚至韩国相比还有很大的差距。2001年度则只有从香港科技大学有3篇投稿。 06年有一篇文章来自中国大陆。
和检查量大)
金属等材料的组合
逐个依次组装 (平行加工、串行组装)
立体大
低缺陷、润滑等人造物体
机械之小、微、纳？
在微小尺寸范围，机械依其特征尺寸可以划分为1-10mm的小型机械，1um-1mm的微型机械以及1nm-1um的纳米机械。所谓微型机械从广义上来讲包含了微小型和纳米机械。

一种新型的双阈值4T SRAM单元的设计

一种新型的双阈值4T SRAM单元的设计
张露漩;乔树山;郝旭丹
【期刊名称】《电子技术应用》
【年(卷),期】2018(44)11
【摘要】通过减少晶体管数目来达到减小存储单元面积,从而实现高密度的SRAM 设计是一种较为直接的解决方案。

在至关重要的SRAM存储单元设计中,不同工作状态表现出的稳定特性是评判SRAM设计的重要指标。

比较了55 nm CMOS工艺节点下传统6T和4T SRAM存储单元的数据保持和读写工作时的稳定特性。

经过多次蒙特卡洛仿真,仿真结果表明,4T结构SRAM与传统6T结构相比,存储单元面积减小20%,在相同供电电压下,通过在外围电路中增加读辅助电路,读稳定性提升了110%,写能力增强183%。

【总页数】4页(P21-23)
【关键词】SRAM存储单元;稳定性;读辅助电路;写能力
【作者】张露漩;乔树山;郝旭丹
【作者单位】中国科学院大学微电子学院;中国科学院微电子研究所;中芯国际集成电路制造有限公司
【正文语种】中文
【中图分类】TN47
【相关文献】
1.一种用于提高读写操作的新型8管SRAM单元设计 [J], 李颂;孟坚
2.一种解决半选择问题的亚阈值9T SRAM存储单元 [J], 黄海超
3.一种新型亚阈值SRAM单元设计 [J], 孔得斌; 乔树山; 袁甲
4.以双字线双阈值4T SRAM为基础的存内计算设计 [J], 蔺智挺;钮建超;吴秀龙;彭春雨
5.一种优化低电压SRAM灵敏放大器时序的4T双复制位线延迟技术 [J], 叶亚东;吴秀龙;蔺智挺
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10
Al-Cu-Mg-Si System Phase Fractions for 6013 – compare to 2014 alloy
Liq
Mg2Si Q
Cu=0.9 wt% Mg=0.9 wt% Si=0.7 wt%
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016
19
Summary: Heat-Treatable Alloys Intermetallic Compounds
2xxx
Constituents Insoluble Al7Cu2Fe Mg2Si Soluble Al2Cu() Al2CuMg(S) Al20Cu2Mn3
6xxx
Al12(Fe,Mn)3Si Mg2Si
Al+q+Q+Si
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016
8
• Q-phase is a quaternary(四元的) intermetallic precipitate with a composition of ~ Al4CuMg5Si4 • Alloy 2014 is the major commercial alloy containing Q-phase. • The alloy is used for aircraft wheels and oil drilling pipe – both are applications which require:
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016
13
Al-Mg-Si System (6xxx Alloys)
Isopleth Section for Mg:Si Ratio of 1.732
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016
7001
18
Al-Cu-Mg-Zn System (Hi-Cu 7xxx) Isopleth for Cu=1.6 wt%, Mg=1.5 wt%
Al-Liq + Al-fcc
Al-fcc
7085
Al + M Al + S Al + M + S
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016
Al + S + q
2124
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016
7
Al-Cu-Mg-Si System Isopleth for 2014
Al Al+q Al+q+Q
Cu=4.6 wt%, Mg=0.4 wt%
Strengthened by Q-phase (Al4CuMg5Si4)
2.0 3.0
1.0
% Magnesium
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016
4
Al-Cu Binary Phase Diagram
Phase Diagrams and Microstructure of HT Alloy Products
Robert Sanders Chongqing University
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016
9
Al-Cu-Mg-Si System Phase Fractions for 2014
Liq q
Cu=4.6 wt% Mg=0.4 wt% Si=0.75 wt%
Q
Si
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016
1.2 6066 1.0 6061
• •
6262, 6020
– Pb, Bi and/or Sn additions for machinability Automotive sheet Excess Si for higher strength
0.8 6063 0.6 6060 0.4 6111 6022 6082
7xxx
Al7Cu2Fe Mg2Si Mg(Zn,Al,Cu)2(M) Mg32(Al,Cu,Zn)49(T) Al12Mg2Cr Al3Zr Al12Mn3Si Mg(Zn,Al,Cu)2
Al4CuMg5Si4(Q) Dispersoids Al12Mn3Si Al12Mg2Cr Mg2Si Al4CuMg5Si4
14
Other Al-Mg-Si Diagrams
1.0% Silicon isopleth Solvus at fixed Si levels
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016
15
GA35266.1
6.0
Aerospace
Strengthened by Ѳ-phase(Al2Cu)
%Copper
5.0 2014 (High Si) 4.0 2024
2324
3.0 2036
Strengthened by S-phase (Al2CuMg)
2.0
Automotiv e
1.0 2008 (High Si)
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016
6
Al-Cu-Mg System (2xxx Alloys)
Isopleth Section at Cu = 4.3 wt%
Al-fcc + Al-Liq
Al
Al + S Al + q
17
Al-Cu-Mg-Zn System (Hi-Cu 7xxx) “Stumpf ” Isopleth(等值线) Cu/Mg/Zn = 1/1.4/3.3
7277
7075
7178
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016
Longitudinal Yield Strength vs. Solute Content of 7xxx Alloy Sheet in Freshly Quenched, W, and Peak Strength, T6, Tempers
(Source: T. Staley, 1992) of Metallurgy andJ. Industrial Application Aluminum Alloys – 2015-2016
Al-Cu-Mg-Si System (Q-Phase Alloys)
• High T6 strength • Good corrosion resistance • High strength at elevated temperature
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016
– “Effective Solute” – Fracture Toughness
Metallurgy and Industrial Application of Aluminum Alloys – 2015-2016 2
Phase Diagrams will determine:
– What amount of alloying elements I can dissolve (strength of final product) – Phases present after Solidification (Casting) – Homogenization temperature – Microstructure changes after heating or annealing – Temperature limits for Solution Heat Treatment
1
Outline: HT Alloy Microstructure
• Phase Diagrams for HT Alloy Systems
– Al-Mg-Si-(Cu) – Al-Cu-(Mg) – Al-Zn-Mg-(Cu)
• Dispersoid Additions: Cr, Mn, Zr • Effects of Fe and Si Impurities
1.0
7072
Fin Stock Cladding
1.0
2.0
3.0
4.0
5.0
Metallurgy and Industrial Application of % Magnesium Aluminum Alloys – 2015-2016
16
7xxx Alloys: Strength vs. Solute
Typical 7xxx Compositions
9.0 8.0 7055 7046 7.0 7050 6.0 Commercial & Auto 7075 7029 Aerospace (High Cu)