基体电导率对0-3型铁电复合材料高压极化行为及损耗的影响

提出了一个0-3型聚合物基铁电复合材料的直流高压极化模型.模型中考虑了聚合物/铁电陶瓷界面处自由电荷的积聚及极化初始时刻的真实情况,利用拉普拉斯静电场方程,并结合边界条件,得到了直流高压极化过程中复合材料的极化强度、界面电流密度等随时间的演化方程,同时得到介电常数、介质损耗等物理特性的表达式.此外,实验制备了分别以环氧树脂E-44和铁电共聚物P(VDF-TrFE)为基体的两种0-3型铁电复合材料.从理论和实验两方面研究了基体电导率对极化行为以及介质损耗的影响.两方面结果均表明：随基体电导率增加,极化时间缩短,陶瓷相的极化强度及复合材料的整体电性能提高,但是漏电流及介质损耗增加.而且实验结果与直流高压极化模型的预测结果符合. 关键词： 铁电复合材料 电导率 极化 介质损耗     

高压对冲空化射流降解有机废水的实验研究

水力空化是一种新型污水处理技术,但目前研究较多的孔板、文丘里管等简单的空化发生装置处理效果不甚理想。本文提出高压对冲空化射流强化有机物降解的概念,并开发了一种新型污水处理装置,并以含典型染料罗丹明B的废水降解为例,进行了系统实验研究.结果表明:高压对冲空化射流对含有罗丹B的废水有良好降解效果.单独采用高压对冲空化射流技术,罗丹明B降解过程符合一阶反应动力学特性,最优条件下罗丹明B降解率可达到71%.与单喷嘴射流相比,射流对冲作用可以将罗丹明B降解率提高1.3倍.对冲空化射流与过氧化氢氧化在罗丹明B降解过程中存在相互强化作用。高压对冲空化射流装置在能量利用率方面存在明显优势.本文的研究结果可为水力空化在污水处理领域的实际应用提供数据支撑.     

物理技术在食品贮藏与果蔬保鲜中的应用

将物理技术应用于食品果蔬的杀菌保鲜，为食品贮藏与保鲜工作开辟了一条新的途径，大量实验表明应用辐射场、静电场、高压脉冲电场、微波等物理技术处理食品果蔬可在不破坏食品的营养结构与原有风味的基础上起到杀虫、灭菌、防腐保鲜的作用。文章综述了近年来物理技术在食品杀菌与保鲜方面取得的研究与应用发展，并对其未来的发展方向作了初步展望。     

可视化静电场分布实验装置设计开发

根据静电场和极化原理,利用高压直流电源、不同形状电极、电机以及arudino单片机等器材,设计并制作了一种可视化静电场分布的实验教学装置。实现了对现教学用模拟法测绘静电场装置所用不同形状电极产生静电场的直接观测,以同轴柱面电极为例,实验现象结果与Comsol模拟结果相符,并基于该实验装置开发了其虚拟仿真实验,有效辅助大学物理实验教学的开展。     

高压静电场抗垢性能的实验研究

通过静态和动态两种方法,进行了高压静电抗垢强化传热实验研究.静态实验结果表明,高压静电场能够使污垢晶体形态发生改变,由六面体结构变为树枝状和薄片状结构,并促进污垢晶体尺寸的增大.动态实验结果表明,成垢溶液经过高压静电处理以后,污垢热阻明显减小,流速的增大能够增强抗垢能力.     

高压静电场与激光对食醋的联合作用

这个实验利用高压静电场和激光同时催陈食醋，用气相色谱法和化学分析方法对催陈食醋的１８种氨基酸，香气成分、总酸、总酯、色度多方面进行了分析。分析结构表明，高压静电场和激光催陈食醋，使食醋的色，香、味均有明显提高，达到了食醋传统贮存陈酿的目的，而且这种方法优于单纯用高压静电场催陈食醋。     

静电场强化介电流体冷凝换热实验研究

本文以电绝缘性低沸点介电流体R11为实验工质,利用自行设计和制作的电流体力学实验模型,对介电流体进 行静电场强化冷凝换热实验研究。实验结果表明:静电场对模型内介电流体的凝结换热有很好的强化作用,其换热系数主 要与外加电场强度、热通量及电极相对位置等因素有关,这种电场强化凝结换热技术对制冷和热传递工程具有参考价值。     

光电反馈式静电悬浮的光电控制系统

本文给出了基于直流高压静电场的光电反馈式静电悬浮系统的实现方案,介绍其工作原理,主要讨论该悬浮操作的技术核心-光电控制系统,提出了光电控制系统中的单元技术:激光三角法测距和比例积分差动(PID)控制的实现方案.我们采用仅有一路伺服控制的光电控制系统进行实验,获得了绞好的结果.实现了悬浮体的开关式悬浮控制.证明了我们的光电控制系统是完全可行的.     

静电场描绘仪的改进

传统的模拟法静电场描绘仪存在的缺陷,针对这些缺陷提出了改进方案.通过实验比较,改进后的描绘仪能很好地模拟描绘静电场,值得推广.     

粉末活性炭吸附对氨基苯酚模拟废水的效果

在静态条件下,研究了活性炭吸附对氨基苯酚模拟废水的效果,确定了处理废水的pH值、活性炭用量、振荡时间、温度、废水中对氨基苯酚浓度、振荡速率以及电解质对吸附效果的影响.实验表明L活性炭在pH值为6.4,用量4.5g,温度35C,振荡2.5h的条件下,对100mL质量浓度为50mg/L的对氨基苯酚模拟废水处理效果最佳.     

The dynamical crossover phenomenon in bulk water, confined water and protein hydration water

We discuss a phenomenon regarding water that was until recently a subject of scientific controversy, i.e. the dynamical crossover from fragile-to-strong glass-forming material, for both bulk and protein hydration water. Such a crossover is characterized by a temperature T(L) at which significant dynamical changes occur, such as violation of the Stokes-Einstein relation and changes of behaviour of homologous transport parameters such as the density relaxation time and the viscosity. In this respect we will consider carefully the dynamic properties of water-protein systems. More precisely, we will study proteins and their hydration water as far as bulk and confined water. In order to clarify the controversy we will discuss in a comparative way many previous and new experimental data that have emerged using different techniques and molecular dynamic simulation (MD). We point out the reasons for the different dynamical findings from the use of different experimental techniques.     

Liquid water

Electron-diffraction measurements for heavy and light water at 5°C are presented and analysed in terms of atom-atom pair-correlation functions and molecular correlation functions.     

The structure of the water molecule in liquid water

The slow neutron scattering measurements of Walford, Clarke and Dore for liquid heavy water at 21°C for incident neutron wavelengths of 0·694 Å and 0·347 Å [7] have been reinterpreted using a sophisticated correction for recoil and detector effects [10] for the molecular contribution to the scattering cross-section. For momentum transfer greater than 6 Å^-1 the liquid structure contribution is negligible and a very good agreement between theory and experiment is obtained. It is concluded that the intramolecular oxygen nucleus-deuteron distance is 0·98₃±0·00₈ Å, and that the deuteron-deuteron distance is 1·55±0·02 Å. This molecular structure is nearer to that of the molecule in the vapour than that in ice I for the conventional interpretation for ice I. It is concluded that there is an environmental effect on the molecular internuclear distances at most of order 0·01 Å for the molecule in the orthobaric liquid near the triple point.     

Enhancement of water self-diffusion at super-hydrophilic surface with ordered water

It has been well acknowledged that molecular water structures at the interface play an important role in the surface properties, such as wetting behavior or surface frictions. Using molecular dynamics simulation, we show that the water self-diffusion on the top of the first ordered water layer can be enhanced near a super-hydrophilic solid surface. This is attributed to the fewer number of hydrogen bonds between the first ordered water layer and water molecules above this layer, where the ordered water structures induce much slower relaxation behavior of water dipole and longer lifetime of hydrogen bonds formed within the first layer.     

SHMFF水冷系统蓄水罐与冷水机组联合供冷模式研究

稳态强磁场实验装置水冷系统具有大流量、大蓄冷温差的特性。前期设计由于考虑占地、成本等因素,所具备的蓄冷量无法满足今后磁体实验延长实验时间的要求。为扩大蓄冷量,提高冷冻水使用效率,现提出了蓄冷罐联合冷水机组供冷的模式,并将其与自然分层法进行了对比分析。     

Boiling-up of superheated water and water solutions under ultrasound influence

Boiling-up kinetics of superheated distilled water and sodium chloride solution in a glass cell at atmospheric pressure and low superheating of 15–35 °C has been studied far from the boundary of attainable superheating in the area of heterogeneous nucleation. Temperature dependences of average waiting time of superheated liquids boiling-up have been studied experimentally under natural conditions and in the ultrasonic field Waiting time of boiling-up at these temperatures reaches 1000 s, and average time is 600 s. Empirical distribution functions have been found with the use of the waiting time samples obtained by the method of order statistics. Omega-square goodness-of-fit test has shown that they disagree with exponential distribution describing stationary random process of supercritical embryo generation separating the system to macroscopic phases. Thus, it is shown that this random process is not stationary, consequently, nucleation rate to be depending on time.     

巧造水火箭

利用可乐瓶、气筒气管等简易材料制作了水火箭,利用该装置演示了动量守恒原理,并给出了实验注意事项.     

Polyamorphism in water

Water, the most common and important liquid, has peculiar properties like the density maximum at 4 °C. Such properties are thought to stem from complex changes in the bonding-network structure of water molecules. And yet we cannot understand water. The discovery of the high-density amorphous ice (HDA) in 1984 and the discovery of the apparently discontinuous change in volume of amorphous ice in 1985 indicated experimentally clearly the existence of two kinds of disordered structure (polyamorphism) in a one-component condensed-matter system. This fact has changed our viewpoint concerning water and provided a basis for a new explanation; when cooled under pressure, water would separate into two liquids. The peculiar properties of water would be explained by the existence of the separation point: the liquid-liquid critical point (LLCP). Presently, accumulating evidences support this hypothesis. Here, I describe the process of my experimental studies from the discovery of HDA to the search for LLCP together with my thoughts which induced these experiments.