含氟材料分子静电势的研究

驻极体是一种显示永久电极化的电介质材料,类同于磁学上的永久磁铁,但它可以贮存单一电荷并可永久保留电荷或处于电极化状态。天然的驻极体材料有巴西棕榈蜡、松香等。自50年代以来,随着聚合物材料的发展,发现了聚合物驻极体,特别是含氟材料具有极好的电荷贮存能力,从而扩展了驻极体的应用领域。由含氟材料驻极体制成的骨愈膜对新鲜骨折可缩短愈合时间,据动物试验对照显示约可缩短1/3,并对骨不连与延迟连接有一定疗效。文献[2,3]曾对某些生物系统的分子和药物分子进行了研究并报道了用量子化学计算静     

外场作用下CO2分子结构及特性研究

以CC-PVDZ为基组，采用筛选的B1B95密度泛函方法研究了不同外电场对CO2分子结构和特性的影响. 研究发现：CO2的结构参数与电场有明显的依赖关系；CO2分子体系的总能量、偶极矩及HOMO与LUMO能级均会受电场的影响；基于外电场对能隙的影响，可以发现外电场会影响CO2参与化学反应的能力；同时CO2红外光谱的特征峰与光谱强度均会受到外电场的影响，且在外电场作用下CO2还会产生新的红外特征峰，因此可通过外电场对分子红外光谱进行调控，进而便于捕捉相关谱图信息；最后通过考察CO2分子中1C-2O键的解离势垒受外电场的影响情况，发现1C-2O键解离势垒与外电场具有极高的相关性，研究结果为电场降解CO2提供了重要的理论依据.     

自动排尿气垫便盆

专利号：992350883 该产品是一种防水软材料制成的，适用于瘫痪卧床病人使用的便器，它既具备气垫的特点，又具备容器的功能，故既可预防褥疮又可以减轻病人小便时的痛苦及不良反应。     

消雷器静态电场分析的并行计算

以分析新型防雷装置消雷器静态电场为例，提出了一种非常适合于多ＣＰＵ并行计算机上实现的并行算法——“奇偶并行法”．通过算例证实本法既容易实现又效率比较高．同时也很容易推广到其它数值计算领域．最后，给出了伞形导体消雷的静态电场分布，并且首次提出了判别消雷器设计期间的优劣标准，为进一步设计消雷器提供了一定的理论基础．     

特种纸大有开发潜力

据有关部门提供的情况表明，特种纸大有开发潜力。测温纸这种纸既可以测量气温和体温，也可以用来检查机器运转时的温度变化。防锈纸在纸的表面涂上某种既不容易挥发又不腐蚀金属的化学药剂，从而制成防锈纸。耐火纸在造纸时加入耐火矿物纤维和无机物，制成一种不怕火烧的纸。通常用于包装一些易燃物品。防水纸可以用来印刷耐水书报、长期保存的文件、军事地图等。代布纪在纤维原料中，加进一些混强剂合成纸，可用来制造一次性的衣服、床单。桌布、手巾等用品，既卫生，又方便。耐压纸在木材纤维中加入合成纤维，再经过特殊加工处理后制成一…     

驻极体外静电场对不同参数环孢菌素A贴剂极化特性的影响

以环孢菌素A为模型药物,以不同浓度促渗剂、不同含量模型药物的环孢菌素A贴剂为研究对象,将不同表面电位正极性驻极体产生的外静电场作为电场源,系统研究驻极体引起各类环孢菌素A贴剂的极化规律及其与贴剂参数间的关系.结果显示:驻极体产生的外静电场能引起环孢菌素A贴剂的极化,驻极体的等效表面电位越高,贴剂的极化程度越强;驻极体引起环孢菌素A贴剂的极化与模型药物的含量及促渗剂的浓度密切相关.在特定电场下贴剂的极化强度随模型药物含量和促渗剂浓度的增加而下降;驻极体引起环孢菌素A贴剂的极化程度呈现出:促渗剂的极化 > 模型药物的极化 > 含促渗剂模型药物的极化.结果表明:驻极体外静电场能引起环孢菌素A和促渗剂的极化,极化的环孢菌素A在电场的作用下有望实现可控迁移和释放的目的.      

周界防御报警传感器——振动电缆传感器

目前，在国内外使用较多的振动电缆传感器主要有两种类型，一是驻极体电缆传感器，另一种是电磁感应式电缆传感器。一、驻极体振动电缆传感器驻极体电缆的结构与普通的同轴电缆很相似，只不过它是一种经过特殊加工处理过的同轴电缆。在制造同轴电缆时，对填充在其内、外导体之间的电介质进行了静电偏压，使之带有永久性的预置静电荷。驻极体是一种电容器的介电材料，当把这种材料加热到接近其熔点时，施加一个很强的极化电压，就可以得到较永久的预置电荷。当驻极体电缆受到机械振动或因受压而变形时，在电缆的内、外导体之间就会产生一个变…     

温度场与电场在奇异热电效应中的协同

以非平衡热动力学的线性唯象关系为基础，研究了特定热电效应中电场与温度场协同的作用，从理论上解析了实验结果。进而既验证了非平衡热动力学线性唯象关系的正确性，又为自然界中普遍存在场协同作用提供了一个例证。     

智能调光材料透光率研究

研究了一种调光材料的配方优化及其作用效果．优化配比溶液的转变温度可以控制在24℃左右，接近人居舒适温度．该材料在低于24℃时透光率较高，可达92％，在高于24℃时的透光率则随温度的升高逐渐下降，最低透光率仅为2％，且溶液在从高温降低到转变温度点以下，溶液的透光率又恢复，具有可逆性．同时借助紫外可见分光光度计和模拟实验分别从理论和实践上表明了该种智能调光材料的可应用性，为建筑物智能降温提供了可能性．     

科技简讯

“驻极体空气过滤材料的研制”通过成果鉴定　　 2 0 0 5年 4月 8日 ,杭州市科技局组织召开了由我校功能材料研究所所长陈钢进教授主持的杭州市科技发展计划项目“驻极体空气过滤材料的研制”的鉴定会。该项目采用自行设计的可控温电晕注极方法 ,对用热黏合工艺制得的多孔 PTFE复合膜进行驻极体改造 ,制备得到了新型驻极体空气过滤材料 ;将该材料用作口罩内层主体过滤层 ,设计制备了新型驻极体抗菌防护口罩 ;并在项目实施过程中 ,成功开发了可用于工业化生产的电晕注极方法和设备 ,已产生显著的经济效益。与会专家听取了项目工作报告、试…     

A theoretical model for mid-and low-latitude ionospheric electric fields in realistic geomagnetic fields

The geomagnetic fields, which play important roles in the ionospheric dynamo, can greatly affect the global distribution of ionospheric electric fields, currents and other ionospheric electrodynamics phenomena. In the study of ionospheric electrodynamics phenomena, such as the longitudinal variations of ionospheric electric fields, the non-dipolar component of the geomagnetic fields must be taken into account. In this paper, we deduce a theoretical electric field model for ionospheric dynamo at mid- and low-latitude which adopt a modified magnetic apex coordinates system. In the new electric field model, the geomagnetic fields can be calculated from either the IGRF model or the dipole field model, and the neutral winds and conductivities are calculated based on empirical models. Then the dynamo equation for the electric potential is finally solved in terms of the line-by-line iteration method, and the ionospheric electric fields and currents are derived from the calculated potential. Our model can reproduce the main features of the ionospheric electrodynamics processes, so it will be a useful tool for the investigation of the upper atmosphere and ionosphere.     

Magnetization vector manipulation by electric fields

Conventional semiconductor devices use electric fields to control conductivity, a scalar quantity, for information processing. In magnetic materials, the direction of magnetization, a vector quantity, is of fundamental importance. In magnetic data storage, magnetization is manipulated with a current-generated magnetic field (Oersted-Ampère field), and spin current is being studied for use in non-volatile magnetic memories. To make control of magnetization fully compatible with semiconductor devices, it is highly desirable to control magnetization using electric fields. Conventionally, this is achieved by means of magnetostriction produced by mechanically generated strain through the use of piezoelectricity. Multiferroics have been widely studied in an alternative approach where ferroelectricity is combined with ferromagnetism. Magnetic-field control of electric polarization has been reported in these multiferroics using the magnetoelectric effect, but the inverse effect-direct electrical control of magnetization-has not so far been observed. Here we show that the manipulation of magnetization can be achieved solely by electric fields in a ferromagnetic semiconductor, (Ga,Mn)As. The magnetic anisotropy, which determines the magnetization direction, depends on the charge carrier (hole) concentration in (Ga,Mn)As. By applying an electric field using a metal-insulator-semiconductor structure, the hole concentration and, thereby, the magnetic anisotropy can be controlled, allowing manipulation of the magnetization direction.     

Demixing in simple fluids induced by electric field gradients

Phase separation in liquid mixtures is mainly controlled by temperature and pressure, but can also be influenced by gravitational, magnetic or electric fields. However, the weak coupling between such fields and concentration fluctuations limits this effect to extreme conditions. For example, mixing induced by uniform electric fields is detectable only at temperatures that are within a few hundredths of degree or less of the phase transition temperature of the system being studied. Here we predict and demonstrate that electric fields can control the phase separation behaviour of mixtures of simple liquids under more practical conditions, provided that the fields are non-uniform. By applying a voltage of 100 V across unevenly spaced electrodes about 50 micro m apart, we can reversibly induce the demixing of paraffin and silicone oil at 1 K above the phase transition temperature of the mixture; when the field gradients are turned off, the mixture becomes homogeneous again. This direct control over phase separation behaviour depends on field intensity, with the electrode geometry determining the length-scale of the effect. We expect that this phenomenon will find a number of nanotechnological applications, particularly as it benefits from field gradients near small conducting objects.     

Characterization of composite particles responsive to electric and magnetic fields

The multilayer particles with responses to electric and magnetic fields are a prerequisite for particles assembled under external fields. Three routes to produce particles responsive to electric and magnetic fields are presented in this article. The size and morphology, properties as well as the electric-magnetic responses of three kinds of particles are comparatively discussed. This will provide a useful basis for the control of the behavior of the particles in suspensions by external electric and magnetic fields.     

静电场中具有对称性的复杂导体电势计算

就静电场中导体的电势计算方法—叠加法加以扩充,对静电场中复杂的导体的电势问题进行了分类讨论,由此解决了很多复杂的静电场中的导体的电势问题。由于处在静电场中的导体达到静电平衡后是一等势体,导体中哪一点(面)的电势能代表整个导体的电势是求解导体电势的关键。就静电场中具有对称性的复杂导体电势的计算采用了新的分析方法和解题技巧。     

大排量螺杆泵技术在海上稠油油田的应用

目前海上油田主要以电潜泵为主要的机采手段,但是在稠油油田,电潜泵存在着泵效低的问题,并且对于超稠油电潜泵无法使用。但是目前电潜螺杆泵在海上的应用,主要受限制于排量低的制约,仅能在产量较低的井中应用;并且在海上实际使用的电潜螺杆泵中,实际使用寿命均较短,不能满足海上油田大排量、长寿命的要求。探讨了对电潜螺杆泵泵型、联轴器、减速器等主要部件进行改进,开发出了排量达到200 m~3/d,实际使用寿命超过一年的电潜螺杆泵,并在海上油田成功应用,取得了较好的效果。     

轮边驱动电动车的转矩协调控制方法

为了解决轮边驱动电动汽车由于控制自由度冗余易造成的操纵稳定性降低的问题,基于逻辑门限值理论设计了一种使车辆能适应转向行驶及直线行驶的驱动转矩协调综合控制系统.该控制系统考虑了车辆转向行驶时轴荷转移、向心力及轮胎侧偏等影响,实现车辆的转向差速控制,使车辆能够按照驾驶员的期望在理想道路轨迹上行驶;并通过对驱动电机转矩进行协调控制,消除非期望横摆力矩的影响,提高车辆在直线行驶过程中的操纵稳定性.仿真结果表明,所提出的转矩协调控制方法改善了轮边驱动电动汽车的操纵性能.     

Influencing intramolecular motion with an alternating electric field

Analogues of mechanical devices that operate on the molecular level, such as shuttles, brakes, ratchets, turnstiles and unidirectional spinning motors, are current targets of both synthetic chemistry and nanotechnology. These structures are designed to restrict the degrees of freedom of submolecular components such that they can only move with respect to each other in a predetermined manner, ideally under the influence of some external stimuli. Alternating-current (a.c.) electric fields are commonly used to probe electronic structure, but can also change the orientation of molecules (a phenomenon exploited in liquid crystal displays), or interact with large-scale molecular motions, such as the backbone fluctuations of semi-rigid polymers. Here we show that modest a.c. fields can be used to monitor and influence the relative motion within certain rotaxanes, molecules comprising a ring that rotates around a linear 'thread' carrying bulky 'stoppers' at each end. We observe strong birefringence at frequencies that correspond to the rate at which the molecular ring pirouettes about the thread, with the frequency of maximum birefringence, and by inference also the rate of ring pirouetting giving rise to it, changing as the electric field strength is varied. Computer simulations and nuclear magnetic resonance spectroscopy show the ring rotation to be the only dynamic process occurring on a timescale corresponding to the frequency of maximum birefringence, thus confirming that mechanical motion within the rotaxanes can be addressed, and to some extent controlled, by oscillating electric fields.     

Lie map for the nonlinear transport of continuous intense beams in the axial-symmetric electrostatic fields

Nonlinear transport of intense continuous beam in the axial-symmetric electrostatic fields is analyzed with the Lie algebraic method. The K-V particle distribution is adopted in the analysis. The results obtained can be used in the calculations of the intense continuous beam dynamics in the beam optical systems consisting of drift spaces, electrostatic lenses, and DC electrostatic accelerating tubes. A computer code has been designed for practical simulations. To meet the needs of accurate calculation, all the elements are divided into many small segments, the electric fields in each segment are regarded as uniform fields, and the dividing points are treated as thin lenses. Iteration procedures are adopted in the code to obtain self-consistent solutions. The code can be used to design low energy dc beam transport systems, electrostatic accelerators, and ion implantation machines.     

电流场透地通信电场的数学建模与分析

电流场透地通信系统通过收发两端插入地下的电极,以电场电流的形式承载信息数据,完成信号的发送和接收,能够实现超过300米的传输范围,并且具有传输衰减小、天线尺寸小、灵活性好等优势。为了有效提高电流场透地通信系统的性能,了解地下电场的分布是具有十分重要意义的。本文构建了地下电场的三维模型,给出了三个电场分量的完整显式解,并基于模型与表达式,仿真分析了收发天线的偏移量、相对方位、长度以及工作频率对电场分布的影响。结果表明,通过合理地选择这些参数能够有效提高接收电极的接收电压,从而改进地面与地下的通信效果。