A coplanar capillary plasma electrode discharge is a promising source owing to its superior performance. In this study, a coplanar capillary plasma electrode discharge flat-panel plasma lamp fabricated from porous anodic alumina and glass was designed to investigate its properties. Coplanar capillary plasma electrode discharge flat-panel lamps with porous anodic alumina dielectric layers were fabricated and investigated. Changing of the frequency and voltage of the power supply and altering of the thickness of the dielectric layers and the interval distance of the electrode were carried out to optimize the performance of the lamps by decreasing the spark-ignition voltage and enhancing the luminous efficacy. The luminance can exceed 7200 Cd/m2 and the white light flux efficacy is more than 4.92 lm/W. The discharge process of capillary plasma electrode discharge was modeled and simulated using COMSOL Multiphysics. The electron density and temperature were also analyzed. The results show that small plasma jets were produced at the pores of the porous anodic alumina, which helped stabilize the plasma. The voltage in the gas gap changes sharply with the geometry of the porous anodic alumina dielectric layer, leading to a higher electric field. The spark-ignition voltage decreased. Small plasma jets increase the plasma uniformity. The electron density and electron temperature reach approximately 1.94 × 108 m3 and 3.34 eV, respectively. A high electric field intensity produced at the porous anodic alumina validated the promising potential in related fields.

为了提高大气压下介质阻挡放电的稳定性,采用阳极氧化方式在铝板表面制备一层多孔阳极氧化铝(Porous anodic alumina,PAA).运用扫描电子显微镜、划痕仪、金相显微镜和台阶仪测试了阳极氧化铝的表面形貌、厚度等特性.比较分析了石英、陶瓷和PAA为介质的大气压下介质阻挡放电的放电过程图片和放电波形.实验表明:应用阳极氧化法制备的多孔阳极氧化铝具有规则的纳米级多孔结构,膜基结合力好;应用多孔阳极氧化铝作为介质的介质阻挡放电更稳定,放电中产生的更密的微放电有助于降低放电击穿电压和提高放电稳定性;更厚的多孔阳极氧化铝膜为介质的大气压介质阻挡放电具有更好的放电稳定性.

为了研究楔形介质层对大气压介质阻挡放电的影响,加入楔形石英石作为附加介质层.通过实验和模拟分析的方法研究了楔形介质层对大气压介质阻挡放电的影响.结果表明:楔形介质层对介质阻挡放电有很大影响,放电在楔形介质层的尖端区域首先击穿,再沿介质层表面弥散.楔形介质层内部出现的场强"低谷区",提高了其尖端附近的电场强度;楔形介质层提高了介质层表面积,介质表面积累的电荷改变了空间电场分布,对放电击穿、电子密度和电子温度有很大影响.介质层厚度引起的放电优先性问题为相关设计提供了更多的灵活性.

通过实验和模拟方式,对比分析了介质阻挡放电和基于多孔阳极氧化铝的毛细管等离子体电极放电.应用阳极氧化法制备的多孔阳极氧化铝(Porous anodic alumina,PAA)作为介质层进行了毛细管等离子体电极放电.研究了多孔阳极氧化铝介质层对毛细管等离子体电极放电的影响,对比分析了相同几何参量的介质阻挡放电和毛细管等离子体电极放电的放电过程.结果表明:应用多孔阳极氧化铝介质的毛细管等离子体电极放电更稳定,放电中产生的更密的微放电有助于提高放电的稳定性;多孔阳极氧化铝介质层的毛细管等离子体电极放电具有相对于介质阻挡放电高出两个数量级的电子密度和更高的电子温度.等离子体参数具有与多孔阳极氧化铝的孔分布同步的周期性,产生了等离子体射流模式,提高了放电稳定性.

为实现锅炉软化水设备正常运行,降低燃料的利用率,采用电压空间矢量脉冲宽度调制技术建立供电电源的主电路及相关模型.论证了主要电力电子器件的设计与选择、空间矢量调制以及dq坐标变换,确定了SVPWM控制方法在锅炉软化水设备中的实用可行性.利用Simulink仿真软件和实验平台,对SVPWM整流电源进行建模和实验调试,得出研究结果能满足软化水设备的需求,改善水质的同时降低电源电磁干扰和开关噪声,提高电源变换效率,具有较好的控制性能.

为了研究磁约束聚变装置支撑装置紧固件的螺母和螺栓表面防咬死涂层的均匀性,利用磁控溅射技术在管形器件的内表面和外表面制备了铜膜,应用台阶仪进行薄膜厚度测试.采用矩形铜板作为磁控溅射靶,采用单自转和公转加自转两种方式进行沉积,分析了铜膜在管形器件的内表面和外表面的膜厚分布规律.结果表明:无论螺母还是螺栓,公转加自转相对于单自转制备薄膜的均匀性都更好,随着孔(管)径的变小薄膜厚度变大.

采用阳极氧化铝作为介质层,设计制作了共面介质阻挡放电等离子体平板光源,研究了高温烘焙、电源频率和气体压强等对光源着火电压和发光效率的影响.结果表明,高温烘焙电极装置和高脉冲电源频率可以使共面介质阻挡放电光源放电更稳定,放电着火电压更低;当电极宽度为0.5 mm、间距为4.5 mm、介质层厚度约为20 μm、气体压强为20 Torr时,共面介质阻挡放电等离子体光源的放电稳定,亮度为7200 cd/m2,白光发光效率为4.92 lm/W.

为研究霍尔推力器通道内放电过程和等离子体的分布情况,对霍尔推力器建立二维仿真模型.得到推力器通道中Xe+和Xe++数密度分布、速度分布、电流密度分布、电势分布和电子温度分布等,通过不同时刻Xe+和Xe++离子数密度的变化,观察到推力器内放电达到稳定运行的过程.由结果可知此推力器工作电压350V,电流4.2A,工质气体流量42SCCM时的比冲约为1300S.与文献中报道的实验结果和数值模拟结果对比,具有很好的一致性.一方面验证了该模型用于霍尔推力器数值仿真的有效性,另一方面得到了稳态霍尔推力器内较详细的放电等离子体参数分布.

采用不可压N-S方程、标准k-ε湍流模型、SIMPLE算法,对某压水堆的两跨距5×5燃料组件的水循环区域流动进行数值分析.对比流道横截面上的压降、速度及其横向分量的相对误差,得到计算域的进出口段长度、网格形式、网格尺寸的选取标准.结果显示:计算域的进口段、出口段长度不宜过短或过长,分别为2.0倍、2.3～2.8倍格架中心距长度;格架区宜采用非结构蜂窝网格,光棒区宜采用结构网格;格架区网格尺寸可取0.3 mm,最大不宜超过0.35 mm,而结构网格横向尺寸可取0.3 mm～0.5 mm,纵向稀疏比应小于1.5为宜.满足上述标准,数值分析能保证较高的可信度,同时保持可接受的计算量.

放射源在核技术应用中有着至关重要的地位,是整个产业链的最上端环节.钴源是核技术应用中常用的放射源和辐照源.目前我国在秦山有两座CANDU-6型重水反应堆生产60Co,尚不能满足我国需求,放射源大量依赖国外进口.若能利用目前广泛运行的压水堆制备钴源,并提高60Co的辐照活度,在不影响发电需求和燃料利用效率、确保堆芯安全的前提下,具有很好的前景.本文使用带燃耗功能的蒙特卡罗程序Serpent计算了新型组件在不同排列方式下60Co的生产效率.计算了富集度分别为4.45％和3.1％的燃料组件,选取对称的4个控制棒导向管位置布置59Co元件棒,并改变其周围4根以及8根燃料棒的富集度或材料,比较其60Co的生产效率.计算结果表明低富集度组件的生产效率明显要高于高富集度组件,而且当60Co元件棒周围的燃料棒替换为水棒时,生产效率还会有进一步显著提升.当组件燃耗达到50 MWd/kgU时,60Co的放射性比活度能达到182 Ci/g,能满足大多数情况下的要求,有利于提高中子利用效率.

从毕奥-萨伐尔的基本定律出发,引入有效半径、有效空间位置和有效空间取向等概念,通过比较电流环和磁偶极场的远场近似计算与严格的带电螺线管磁场的计算结果,采用优化螺线管结构和构建计算模型,可以有效地克服螺线管本身带来的空间磁场有限长度效应.在有效空间范围内进行数值模拟的结果表明,磁偶极场的远场近似不仅可以满足磁场计算的精度要求,而且具有极高的计算速度.可以实时地实现具有多带电螺线管复杂结构的电磁计算,满足电磁空间定位和电磁导航的要求.

针对目前微创手术机器人定位系统中,由于电磁定位技术在实际应用中出现定位误差大的问题,提出了一种六自由度电磁定位系统的实用设计。对在设计的空间范围内进行仿真,分析了激励系统中线圈在空间产生的磁场及其几何尺寸的优化,利用四元数的快速迭代特性和计算过程无奇异解的特性实现线圈姿态变换,创建了定位系统设计的操作平台,并进行计算仿真比较,结果表明,改进实用模型可行可靠,定位系统可以达到1 mm的定位精度,可有效地克服线圈的有限长效应引起的偏差大,并能够提高微创手术定位的实用性。

In order to simulate the communication signals attenuation, the model of plasma sheath is based on the layer theory and the modified double exponential model in blackout. The results of simulation show that: The attenuation constant reaches a peak value when the angular frequency of communication signal is equal to the natural angular frequency of the plasma, and the different collision angular frequency of plasma has different the peak value of attenuation. In addition, the peak value and bandwidth of attenuation is a contradiction. As electron density increases, the attenuation constant increases rapidly. When the temperature is below 1000K, the attenuation constant increases rapidly, and then reduces slowly.

研究设计了基于中国实验快堆(China Experimental Fast Reactor,CEFR)的小型“行波”概念堆.采用中子输运程序MCNP和点燃耗程序ORIGEN2的耦合程序进行堆芯设计,重点研究了不同点火组件的富集度和不同布料方案对小型堆的物理参数的影响,设计堆芯寿期为30 a,并给出相应的倒料方案.不同点火组件富集度对比结果表明,小堆需要选取合适的富集度,富集度太低无法维持临界,而太高会影响堆芯增殖效应;而低泄漏和棋盘式布料两种方式对比结果表明,后者的增殖组件增殖效应明显高于前者.最终确定倒料周期为8a,倒料三次,堆芯实现较长寿期,且整个寿期内反应性变化小,各组件燃耗深度相对均匀,组件平均卸料燃耗深度约为238 MWD/kgHM.

The plasma facing components (PFCs) of W/CuCrZr divertor for international thermonuclear experimental reactor (ITER) were.manufactured by hot isostatic pressing technique.These fabricated mock-ups are tested under thermal screening heat loads using intense electron beam in pulsed mode.Simulation of high heat flux test under steady state and thermal screening was carried out using ANSYS software.The simulation and calculation results show that during the HHF test,the highest temperature of the fabricated mock-ups appear in the W surface,and the highest temperature increases with an increase in the thickness of W block and absorbing power density of the Wblock.Three kinds of W-blocks with different intermediate layer,when the thickness is less than 8 mm and the absorbed power density is less than 8 MW/m2,the highest temperature of CuCrZr alloy and W surface are satisfied the PFCs design allowable temperature requirements.

本文针对电磁定位导航系统的应用及其体积的微型化、结构的简单化和定位导航精度存在的问题,从系统设计的角度出发,提出了一种探测探头6D电磁导航的快速数值算法和模型,经仿真实验证明了此方法能实现高速高精度电磁定位导航,从而提高电磁定位导航系统的性能及应用范围.

In the fast Z-pinch experiments, the beam-target neutrons, the Deuterium-Deuterium neutrons and Deuterium-Tritium neutrons can be generated. It is a good idea to use deuterium Z-pinch plasmas to generate fusion neutrons which can be used in the fusion-fission breeders. The common design of Z-pinch plasmas apparatuses was introduced. The design of Z-pinch apparatuses for fusion-fission breeders is proposed.

A fast numerical algorithm is proposed for the 6 degrees of freedom electromagnetic navigation system, which can be used to improve surgical operations guided by medical images. Both the rotation transformation technique and optimization technique are adopted in the algorithm. The results from simulations show that the calculating time is improved greatly under the required precision in the surgery. A navigation system based on the algorithm can make the medical device's dimensions miniaturized and the structure simplified and portable. The performance and application scope of the electromagnetic positioning navigation system can be improved.

In this study, the heating of ions with a Kappa (κ) velocity distribution by an Alfvén wave propagating along an external magnetic field via non-resonant wave–particle interactions in low-beta plasmas is investigated by means of both quasilinear theory and test-particle simulation. The κ velocity distribution is most suitable for describing a non-thermal distribution with an enhanced high-energy tail and includes the Boltzmann distribution as a limiting case. Because of the thermal non-equilibrium factor (κ factor), the heating effect of κ ions is weaker than that of Boltzmann ions, and when κ→∞, the heating effects become identical. It is determined that the ion pickup increases as the κ parameter increases, and the heating is dominant in the perpendicular (to the background magnetic field) direction. Subsequently, during the heating process, ions are also accelerated in the parallel direction. This phenomenon may have relevance to the heating of ions in the solar corona and to ion heating in some toroidal-confinement fusion devices.

The present paper addresses the nonresonant and stochastic heating of minor ions by a low-frequency Alfvén wave in the solar wind. A new and whole physical mechanism that enables the heating of ions by a low-frequency parallel propagating wave with finite amplitude in a low beta plasma. The heating process has two stages: First, ions are picked up via low-frequency wave–ion nonresonant interaction and the ion energy gain depends on the ratio of the wave electric-field energy to background magnetic-field energy. Second, when the velocity approaches the threshold value, the stochastic heating is prominent. The stochastic heating of ions sustains until the average parallel speed is close to the wave velocity.