Multi-field coupling and free vibration of a sandwiched functionally-graded piezoelectric semiconductor plate

Sandwiched functionally-graded piezoelectric semiconductor(FGPS)plates possess high strength and excellent piezoelectric and semiconductor properties,and have significant potential applications in micro-electro-mechanical systems.The multi-field coupling and free vibration of a sandwiched FGPS plate are studied,and the governing equation and natural frequency are derived with the consideration of electron movement.The material properties in the functionally-graded layers are assumed to vary smoothly,and the first-order shear deformation theory is introduced to derive the multi-field coupling in the plate.The total strain energy of the plate is obtained,and the governing equations are presented by using Hamilton’s principle.By introducing the boundary conditions,the coupling physical fields are solved.In numerical examples,the natural frequencies of sandwiched FGPS plates under different geometrical and physical parameters are discussed.It is found that the initial electron density can be used to modulate the natural frequencies and vibrational displacement of sandwiched FGPS plates in the case of nano-size.The effects of the material properties of FGPS layers on the natural frequencies are also examined in detail.

Transient analysis on surface heated piezoelectric semiconductor plate lying on rigid substrate

Based on the thermo-electro-elastic coupling theory,the mathematical model for a surface heated piezoelectric semiconductor(PS)plate is developed in the time domain.Applying the direct and inverse Laplace transformations to the established model,the mechanical and electrical responses are investigated.The comparison between the analytical solution and the finite element method(FEM)is conducted,which illustrates the validity of the derivation.The calculated results show that the maximum values of the mechanical and electrical fields appear at the heating surface.Importantly,the perturbation carriers tend to concentrate in the zone near the heating surface under the given boundary conditions.It can also be observed that the heating induced elastic wave leads to jumps for the electric potential and perturbation carrier density at the wavefront.When the thermal relaxation time is introduced,all the field quantities become smaller because of the thermal lagging effect.Meanwhile,it can be found that the thermal relaxation time can describe the smooth variation at the jump position.Besides,for a plate with P-N junction,the effect of the interface position on the electrical response is studied.The effects of the initial carrier density on the electrical properties are discussed in detail.The conclusions in this article can be the guidance for the design of PS devices serving in thermal environment.

Analysis of piezoelectric semiconductor fibers under gradient temperature changes

Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor devices.PS fiber-like structures have wide applications in multi-functional semiconductor devices.In this paper,a one-dimensional(1D)theoretical model is established to describe the piezotronic responses of a PS fiber under gradient temperature changes.The theoretical model aims to explain the mechanism behind the resistance change caused by such gradient temperature changes.Numerical results demonstrate that a gradient temperature change significantly affects the physical fields within the PS fiber,and can induce changes in its surface resistance.It provides important theoretical guidance on the development of piezotronic devices that are sensitive to temperature effects.

Nonlinear magneto-mechanical-thermo coupling characteristic analysis for transport behaviors of carriers in composite multiferroic piezoelectric semiconductor nanoplates with surface effect

In this paper,to better reveal the surface effect and the screening effect as well as the nonlinear multi-field coupling characteristic of the multifunctional piezoelectric semiconductor(PS)nanodevice,and to further improve its working performance,a magneto-mechanical-thermo coupling theoretical model is theoretically established for the extensional analysis of a three-layered magneto-electro-semiconductor coupling laminated nanoplate with the surface effect.Next,by using the current theoretical model,some numerical analyses and discussion about the surface effect,the corresponding critical thickness of the nanoplate,and the distributions of the physical fields(including the electron concentration perturbation,the electric potential,the electric field,the average electric displacement,the effective polarization charge density,and the total charge density)under different initial state electron concentrations,as well as their active manipulation via some external magnetic field,pre-stress,and temperature stimuli,are performed.Utilizing the nonlinear multi-field coupling effect induced by inevitable external stimuli in the device operating environment,this paper not only provides theoretical support for understanding the size-dependent tuning/controlling of carrier transport as well as its screening effect,but also assists the design of a series of multiferroic PS nanodevices.

热处理对铝板基PS版电解腐蚀性能的影响

采用极化曲线测定、扫描电镜和金相显微镜技术,对比国外优质1050 PS版板基,研究了热处理工艺对板基电蚀性能的影响。结果表明,具有大量细及均匀分布的第二相颗粒和均匀晶粒组织的板基电解腐蚀性能好。经过600℃×3 m in的高温快速退火处理后的板基微观组织得到细化,均匀性提高,细小弥散的第二相颗粒大量析出,板基电解活化性能增强,腐蚀均匀、稳定,电解腐蚀性能显著提高。

1050铝基PS版的热处理工艺

本文将厂方提供的1050铝合金PS板基在冷轧至0.9mm厚时进行不同工艺的热处理,利用极化曲线测试仪、扫描电镜、金相显微镜等实验手段研究了热处理前后PS板基的微观组织和电解腐蚀性能的差异,进而探讨了热处理对PS板基电蚀性能的影响规律。结果表明:对材料进行600℃(到温入炉),保温3min空冷至室温再冷轧至0.27mm,板基的微观组织均匀性较处理前有明显改善,电解腐蚀性能明显提高,接近国外优质板基。

1052 PS版铝板基的晶粒细化机制

研究了热轧、中间退火、冷轧制备1052 PS铝板基过程中的晶粒细化机制,观察了各步骤材料的显微组织,对成品板材进行了力学性能分析。结果表明:(1)通过文中所述工艺制备的板材试样的晶粒从210μm减小到20μm左右;(2)试样的晶粒尺寸越小,显微硬度越高;(3)经过中间退火工艺后的试样比未经过中间退火的试样的质量要好些,且经过中间退火后的试样随着冷加工变形量的增加,晶粒尺寸减小,力学性能提高。

国内外PS版用铝板基综合测试与分析

对国内外１０种ＰＳ板基样品进行了综合测试，分析了板基材料在化学成分、表面粗糙度、晶粒度、退火力学性能参数等几项主要指标上的差异及其对最终ＰＳ版质量的影响。

微量元素对1050铝基PS版电蚀性能的影响

研究了Mg、Mn含量对PS版电蚀性能的影响。利用电化学测试仪、扫描电镜及能谱仪检测分析了不同Mg、Mn含量的PS版电解腐蚀速率和腐蚀均匀性的差异。分析表明,Mg含量从0.001%提高到0.10%时,Mg更多地富集于铝板表面,形成微小的易腐蚀的含Mg复合氧化物颗粒,促进腐蚀,进而提高板基的腐蚀速率;Mn含量的增加能提高Mg元素在板基表面的分布均匀性,减少Fe元素在铝板表面的富集,降低Fe对腐蚀均匀性的危害。

2种PS版材感光性能的比较研究

对当前市场通用的2种重氮萘醌系阳图型PS版进行了分光谱曝光显影实验,得到了2种PS版的感光特性曲线,实验发现2种PS版的感度存在较大差异,分别为170m J/cm2、10m J/cm2。进一步从感光层的红外光谱、紫外-可见光谱分析了引起感度差异的因素。

冷轧变形量对PS版电解腐蚀性能的影响

用扫描电镜,透射电镜和金相技术及极化曲线测定等方法,研究了退火前后冷轧变形量对1050铝基PS版微观组织及电解腐蚀性能的影响。结果表明,位错密度大、分布均匀、第二相颗粒多、细小弥散分布的板基电蚀性能好。退火前冷轧变形量的提高,能够促使沉淀相的弥散析出,位错密度则随着最终冷轧变形量的增加而增加。板基在1.2mm厚度进行退火处理后既能获得大量细小、弥散分布的第二相粒子,又能得到较高的位错密度,因而提高了板基的电蚀性能。

1052H19PS版铝板基制备工艺研究

介绍了1052H19PS版铝板基的制备工艺,并测量了试样的表面粗糙度,分析了其显微结构、力学和电解腐蚀性能.结果表明:(1)经过中间退火后的试样其内部的晶格畸变较弱、位错较少,比未经过退火处理的试样强度低、塑性好;(2)中间退火后的试样的表面晶粒较细小、第二相较多,且分布较均匀,其电解腐蚀性能比未经过退火的试样高.

预活化对PS微球化学镀镍的影响

研究了表面化学镀前处理工艺中活化条件（如活化时间、活化温度、活化pH值）对PS微球镀镍层的致密性、均匀性、导电性的影响,对活化后的PS微球进行了SEM和导电性测试。结果表明,在氯化钯用量为0.05g、活化时间为80-120min、活化温度为34℃、活化pH值为3-4的条件下,PS微球具有良好的镀层致密性及优良的导电性。

阴图PS版感光层的光交朕

阴图ＰＳ版感光层的光交朕曹曙光，王仁祥，曹维孝（北京大学化学与分子工程学院，北京１００８７１）关键词重氮树脂；成膜树脂；阴图ＰＳ版；光交联阴图ＰＳ版感光层主要是由成膜树脂和感光树脂组成。感光树脂一般是二苯胺或取代二苯胺重氮树脂．成膜树脂类型较多。就成...

空心阴极N_2等离子体放电光源实现普通PS版感光

本文利用直流空心阴极放电方式产生了一种新型氮气等离子体蓝紫光源,实现了针对传统的预涂感光版(PS版)的感光,当N2气压70 Pa、放电电压580 V、电流1.8 A时,产生的蓝紫光功率密度为0.46 mW/cm2.本文进一步从曝光前后颜色密度值变化、感光材料红外分析方面,对PS版的曝光效果做了详细的测量.

高感度阳图PS版感光剂与涂层的耐醇性

本文绘制了不同酯化母体,不同酯化率重氮萘醌系PAC在异丙醇中的溶解度曲线。通过观察溶解度曲线,选择合成酯化率略高于拐点处酯化率的感光树脂应用到配方研究中。在配方试验中以连苯三酚缩丙酮树脂(简称PA树脂)与2,1—重氮萘醌—5—磺酰氯(简称215)酯化的感光树脂和线性酚醛树脂与2,1—重氮萘醌—4—磺酰氯(简称214)酯化的感光树脂作为阳图PS版感光涂层的感光剂,以线性酚醛树脂作为成膜树脂,通过调节B/P值,可优选出感度高,耐醇、抗碱性能好的阳图PS版感光组成物。

PS版的生产工艺中的常见问题及处理办法

PS版的生产工艺较为复杂,工艺控制要求严格,造成产品质量问题的因素多。本文总结了多年来在PS版生产一线遇到的常见问题及处理办法。

PS版用铝合金上机适用性研究

研究了PS版用铝合金的化学成份及加工工艺对版基性能的影响。

成品PS版的检测和评价

PS版生产厂家众多,产量日益增加,品种也越来越多,建立和完善行之有效的检测和评价体系,益发显得重要。本文通过从表观和性能两个方面,探讨PS版的检测和评价方法,建立了完善的质量检测和评价体系。

普通PS版感光特性的研究

计算机直接制版技术(CTP)是当前印刷技术领域研究的热点问题之一,采用传统PS版的计算机直接制版(CTCP)由于继续沿用传统的预涂感光版(PS版),在印刷适性、耐印力、印品分辨率等方面具有明显的优势,同时成本低,市场量大。但人们对PS版感光材料曝光特性的研究相对较少,本文给出了1种超感度重氮盐PS版的最低曝光能量同波长之间的关系,在波长405nm处所需的临界曝光能量仅为10.35m J/cm2。从曝光前后颜色密度值变化、感光材料红外分析方面,对PS版的曝光效果做了详细的测量。