低功率水工质脉冲等离子体推进器的工作特性

为了解决Teflon脉冲等离子体推进器存在的性能低、有污染等问题,设计了以水为工质的脉冲等离子体推进器系统,并研究了它的主要工作指标的能量阈值.分析了水工质脉冲等离子体推进器系统的放电类型形成条件及原因,通过放电电压和电流测试实验,对工作能量阈值进行了实验研究,得到了稳定运行能量对应的储能电容值.实验结果表明:在足够高...     

等离子体对碳氢燃料点火延迟时间影响的研究进展

应用等离子体减小碳氢燃料点火延迟时间的优越性已经越来越明显。论文总结了点火延迟时间的主要定义和表达方式,分析了等离子体影响碳氢燃料点火过程的重要机理、简化模型以及主要的实验装置,并列举了前面研究者利用等离子体影响碳氢燃料点火延迟时间的实验研究,最后提出了高压纳秒脉冲放电等离子体的应用前景广阔。     

脉冲磁场对神经元瞬时外向钾电流的影响

实验研究了脉冲磁场对小鼠皮层细胞的瞬时外向钾离子通道的影响.采用频率为15Hz、强度为1.4 mT的超低频脉冲磁场对小鼠的脑皮层神经细胞进行刺激,而后应用全细胞膜片钳技术测量其瞬时外向钾电流特性.实验发现,超低频脉冲磁场对瞬时外向钾电流IA有一定的抑制作用,脉冲磁场作用町显著地影响通道的激活,对照组和脉冲磁场作用组通道半数激活电压分别为(13.25±2.22)mV和(30.98士4.11)mV(n=6,P＜O.05),斜率因子分别为(24.00±2.05)mV和(23.30土2.13)mV(n=6,P＞0.05).结果表明,脉冲磁场作用皮层神经细胞町以改变其瞬时外向钾通道的特性,调节神经元的生理功能.     

脉冲诱导放电气体激光器

研究了一种实现新放电方法:诱导圆筒放电的可能性.该放电方法基于不同的粒子数反转机理,使用不同的原子和分子传能模式泵浦气体激光器.研制了用于气体中的脉冲诱导圆筒放电(脉冲感应耦合等离子体)激励系统,并对其进行了实验研究.首次实现了基于原子和分子不同传能模式的4种脉冲诱导激光器,其激励特性是光束发散角小,不同脉冲间的非稳定...     

等离子体钻机高压脉冲传输电缆的研制

设计了等离子钻机高压脉冲传输电缆的结构,讨论了高压绝缘层的设计及材料选择。在此基础上,开展了高压脉冲传输电缆的绝缘阻抗和波阻抗测试实验。实验测试结果表明,所研制的传输电缆具有较高的绝缘性能和较小的波阻抗,可基本满足等离子体钻机的需要。     

降解有机废气的倍频式反应控制系统研究

本文基于大量实验,将电路原理与等离子体化学相结合,提供了一种效果明显、电路设计合理的等离子体降解有机废气的倍频式反应控制系统.该系统的特点是运用双超短脉冲发生电路与电晕发生装置相组合,形成高效降解的倍频效果.本系统对甲苯、二甲苯的降解率可达73～91%左右,对二氯甲烷的降解率可达82%.     

采用脉冲法实现对位移和压力的高精度控制

介绍一种在非线性摩擦影响下,用脉冲对位移和压力精确控制的方法.该方法为两级控制,当离目标值较远时,采用传统的PID控制;当接近目标值时,采用矩形脉冲控制,使设备产生微小运动,实现对位移和压力的精确控制.脉冲的形状由理想位移、压力和转矩脉冲模型通过采用模糊逻辑的方式确定.在大连理工大学微系统研究中心开发的塑料微流控芯片微通道热压成形机(电机驱动)上,对于不同的矩形脉冲产生的位移、压力等进行实验研究,建立了脉冲形状与位移、脉冲形状与压力关系的模型.     

激光等离子体软X射线光源的一种诊断方法

激光等离子体软X射线光源是脉冲式光源,对这类光源的光谱诊断有几种方法.文章介绍了一种新的、实用的测量激光等离子体软X射线光源光谱的方法.此方法以低噪声的通道电子倍增器探测来自光源的ns量级的脉冲光信号,并由低噪声、响应快的电荷灵敏前置放大器进一步将其放大,前放的输出电荷与输入的脉冲信号的峰值成正比.使用这种方法测量了铜靶激光等离子体光源和氧、氪气体靶激光等离子体软X射线源在8～30nm波段的光谱.     

脉冲电晕等离子体烟气脱硫脱硝实验装置

介绍了一种用于燃煤电厂烟气脱硫脱硝的脉冲等离子体实验装置。从工艺、结构等方面对设备进行介绍,并对其内件、喷淋等关键性部位进行描述。通过实验数据的收集及分析,发现该装置对脱硫脱硝效果明显。     

高压脉冲等离子体水处理装置的研制

研制了一种新型水净化处理装置,以取代氯气消毒工艺。装置利用高压脉冲在水雾中介质阻挡放电产生低温等离子体,综合了高能电子辐射、臭氧氧化、紫外光照射等多因素的协同降解作用,使出水达到国家饮用水标准。另外对装置的高压脉冲电源、等离子体发生器的研制提出了新的设计思路。     

A 2 MV Van de Graaff accelerator as a tool for planetary and impact physics research

Investigating the dynamical and physical properties of cosmic dust can reveal a great deal of information about both the dust and its many sources. Over recent years, several spacecraft (e.g., Cassini, Stardust, Galileo, and Ulysses) have successfully characterised interstellar, interplanetary, and circumplanetary dust using a variety of techniques, including in situ analyses and sample return. Charge, mass, and velocity measurements of the dust are performed either directly (induced charge signals) or indirectly (mass and velocity from impact ionisation signals or crater morphology) and constrain the dynamical parameters of the dust grains. Dust compositional information may be obtained via either time-of-flight mass spectrometry of the impact plasma or direct sample return. The accurate and reliable interpretation of collected spacecraft data requires a comprehensive programme of terrestrial instrument calibration. This process involves accelerating suitable solar system analogue dust particles to hypervelocity speeds in the laboratory, an activity performed at the Max Planck Institut fu?r Kernphysik in Heidelberg, Germany. Here, a 2 MV Van de Graaff accelerator electrostatically accelerates charged micron and submicron-sized dust particles to speeds up to 80 km s(-1). Recent advances in dust production and processing have allowed solar system analogue dust particles (silicates and other minerals) to be coated with a thin conductive shell, enabling them to be charged and accelerated. Refinements and upgrades to the beam line instrumentation and electronics now allow for the reliable selection of particles at velocities of 1-80 km s(-1) and with diameters of between 0.05 μm and 5 μm. This ability to select particles for subsequent impact studies based on their charges, masses, or velocities is provided by a particle selection unit (PSU). The PSU contains a field programmable gate array, capable of monitoring in real time the particles' speeds and charges, and is controlled remotely by a custom, platform independent, software package. The new control instrumentation and electronics, together with the wide range of accelerable particle types, allow the controlled investigation of hypervelocity impact phenomena across a hitherto unobtainable range of impact parameters.     

锚杆钻车除尘系统管道优化设计的探讨

介绍了除尘系统管道布置的原则和除尘系统管道计算步骤,分析了除尘系统管道沿程压力损失和局部压力损失,最后根据除尘系统总压损和总风量,确定匹配的风机和马达性能参数。     

导电性工程陶瓷材料的放电加工研究

通过专用脉冲电源脉冲放电能量的控制,进行了导电性工程陶瓷材料的电火花放电加工试验研究,提供了一种稳定加工导电笥工程陶材料且能控制加工质量的电火花放电加工方法。     

货车制动梁电焊工场新型风控排尘系统的设计与实践

本文针对货车制动梁电焊排尘缺乏良好的控制系统而造成能源浪费、通风除尘系统失效的问题,设计了以PLC为核心、以高压风源为动力的完善的控制系统,实现了电焊作业通风除尘的自动控制,达到了节能降耗,提高生产区局部局部污染治理水平的目的。     

消化道药物控释驱动机构的动力学特性研究

药物控释微系统是研究消化道药物吸收特性的一种新技术,其中的驱动机构是实现药物释放的关键技术环节.对电热式驱动机构进行了数学模型分析和实验测试研究.根据牛顿定律及液压传递原理,建立数学分析模型,并利用MALTAB仿真驱动机构活塞的速度-时间曲线及位移-时间曲线.同时,利用高速摄像系统设计了针对电热式驱动机构的测试实验,记录和分析了驱动机构药物释放的动态过程,得到了驱动机构活塞的运动学特征参数.实验结果表明驱动机构活塞的运动由慢-快-慢3个阶段组成,药物释放主要在第2个阶段完成.该研究结果有助于优化药物控释微系统驱动机构的设计.     

STUDY ON THE CHARACTERISTICS OF UNDER WATER PLASMA ARC

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消化道定点施药系统中磁定位信号预处理方法研究

磁定位信号的预处理方法对消化道定点施药系统的定位精度有重要意义。本文对磁信号检测中的普遍存在的地磁场干扰和电磁干扰问题进行了深入研究。针对地磁场干扰,采用静态磁场值来补偿地磁场值;对于电磁干扰,采用滑动平均滤波和小波默认阈值方法分别对静态磁场信号和动态磁场信号进行滤波处理。通过比较发现,小波阈值的方法可以较好地抑制静态磁场信号中的高频噪声,而滑动平均滤波的方法对处理动态磁场信号可以取得较好的效果。     

Poloidal beta and internal inductance measurement on HT-7 superconducting tokamak

Poloidal beta beta(theta) and internal inductance l(i) measurements are very important for tokamak operation. Much more plasma parameters can be inferred from the two parameters, such as the plasma energy confinement time, the plasma toroidal current profile, and magnetohydrodynamics instability. Using diamagnetic and compensation loop, combining with poloidal magnetic probe array signals, poloidal beta beta(theta) and internal inductance l(i) are measured. In this article, the measurement system and arithmetic are introduced. Different experimental results are given in different plasma discharges on HT-7 superconducting tokamak.     

Imaging conductive materials with high frequency electrical capacitance tomography

Electrical capacitance tomography (ECT) is known as an imaging technique for dielectric permittivity imaging. A novel ECT sensor model at a high excitation frequency is proposed to examine the capability of the ECT system to image both conductivity and permittivity contrasts. The proposed model uses a complex impedance forward model for the ECT system. This new model indicates that in higher excitation frequency both conductive and dielectric imaging may be feasible. Normally, capacitance tomography is designed for the measurements of imaginary part and resistance tomography is used to take the measurements of real part. The drawback of a typical capacitance tomography at a low excitation frequency, such as 200 kHz is that it cannot be used to measure the conductive phase of a conductive/dielectric mixed fluid, e.g. the gas/water flow. By increasing the excitation frequency, the capacitive impedance of the conductive material decreases and dielectric phenomena of the conductive fluid dominates so that it is possible to use capacitance tomography to characterise the dielectric/conductive flows. This paper presents a development of capacitance tomography with a high excitation frequency in measuring the gas/liquid mixture i.e. gas/water and gas/oil multiphase distributions. Both theoretical and experimental results are presented to verify this feasibility study.     

In-flight calibration of mesospheric rocket plasma probes

Many effects and factors can influence the efficiency of a rocket plasma probe. These include payload charging, solar illumination, rocket payload orientation and rotation, and dust impact induced secondary charge production. As a consequence, considerable uncertainties can arise in the determination of the effective cross sections of plasma probes and measured electron and ion densities. We present a new method for calibrating mesospheric rocket plasma probes and obtaining reliable measurements of plasma densities. This method can be used if a payload also carries a probe for measuring the dust charge density. It is based on that a dust probe's effective cross section for measuring the charged component of dust normally is nearly equal to its geometric cross section, and it involves the comparison of variations in the dust charge density measured with the dust detector to the corresponding current variations measured with the electron and/or ion probes. In cases in which the dust charge density is significantly smaller than the electron density, the relation between plasma and dust charge density variations can be simplified and used to infer the effective cross sections of the plasma probes. We illustrate the utility of the method by analysing the data from a specific rocket flight of a payload containing both dust and electron probes.