半导体Si中稀土元素杂质与中子辐照缺陷的互作用研究

用１４ＭｅＶ中子辐照掺有稀土元素杂质及未掺稀土元素杂质的ｎ型Ｓｉ，并用红外吸收谱仪和四探针法测量其参数在辐照前后的变化。红外吸收谱测量表明，在单晶硅中的杂质未形成新的自身成份的红外吸收峰，但电阻率测量表明，掺入稀土元素Ｅｒ和Ｇｄ的Ｓｉ电阻率虽都随着中子注入量的增大而增大，但Ｓｉ（Ｅｒ）和Ｓ（的电阻率比率的变化远远小于Ｓｉ的变化。     

EAST-ICRF传输线驻波电流测量

为了测量托卡马克放电期间离子回旋加热系统的传输线电流值,利用电流探针搭建了传输线电流测量系统。对传输线电流测量原理进行简单介绍,并对电流探针的特性进行分析研究,确保电流探针的性能。将实验中用电流探针测得的传输线电流值与电压探针拟合计算得到的传输线电流值进行了对比,验证了传输线电流测量系统的可靠性。     

CT-6B托卡马克的交流运行实验研究

在CT—6B托卡马克上首次实现了多周期交流运行，对多个周期中等离子体进行比较发现，尽管在每个周期的两个半周中等离子体与壁的相互作用有所不同，但等离子体中的杂质积累并未受到严重影响。通过内磁探针测量了等离子体电流密度的分布，发现等离子体电流首先从弱场区开始反相，电流反相过零时同时存在正负局部等离子体电流，此时的磁面结构有效地约束了粒子。     

AlNi纳米合金薄膜低温电阻率的特性研究

通过磁控溅射制备了AlNi纳米合金薄膜,并利用自制的直排四探针低温测量系统测量了薄膜电阻率随温度(8~300K)的变化规律。结果表明:由于电子-声子和电子-磁子相互作用,纯Al和Ni纳米晶薄膜的电阻率分别呈现出正的电阻率温度系数,且电子-磁子散射对电阻率的贡献主要体现在高温区(80~300K),在低温区(40K)电子-晶界/表面散射对电阻率的贡献占主导地位。Ni原子掺入量的增加,诱导了纳米晶薄膜无序程度的增强,从而使Al1-xNix纳米合金薄膜逐渐由晶体的金属特性过渡到半导体特性,导致其呈现出负的电阻率温度系数。由于增强的电子极化效应,Al1-xNix纳米合金薄膜电阻率与温度的关系并不完全遵循半导体的热激发导电模型。     

双探针两相流测量机理的数值模拟

基于流体体积函数(VOF)模型,通过用户自定义标量方程(UDS),建立电导探针测量气-液两相流参数的基本模型。采用所建立的模型对垂直圆管气-液两相流双探头电导探针测量过程进行模拟,得到气泡流动过程中探针外部空间的电场分布。模拟结果显示:气泡通过探针时会引起的电流电压的巨大变化;电流电压分布不受噪声信号、气泡形状变化以及电流电压信号响应滞后的影响。通过模拟得到,当气泡经过探针时会产生电流和电压的近方波信号,该结果能真实反映探针测量气-液两相流的基本过程。     

浅成热液矿脉型金矿床的矿化作用形成的电阻率异常

本文通过对几个具有代表的浅成热液脉型金矿床电阻率异常的分析,说明 CSAMT(可控源声频磁大地电流)法对于勘查该类型金矿床的效果。为确定电阻率和蚀变矿物之间的关系,强调研究蚀变矿物的重要性,并提出了具体研究方法。文章还提出了在勘查隐伏矿床时,应开展模式找矿。     

He离子辐照对锐钛矿TiO_2薄膜结构与性能的影响

用多弧离子镀方法制备锐钛矿二氧化钛(TiO_2)薄膜,研究不同剂量与能量的He离子辐照对TiO_2薄膜结构与性能的影响。用X射线衍射仪(XRD)、激光拉曼光谱(RM)、场发射扫描电镜(SEM)、原子力显微镜(AFM)、四探针仪(FPPT)和紫外可见分光度仪(W)分别表征辐照前后TiO_2薄膜相结构、分子结构、结构形貌、电阻率及光反射率。结果表明:薄膜的相结构未发生明显转变;薄膜电阻率与结晶度发生变化;薄膜柱状结构逐渐消失;辐照剂量一定时,He离子能量越小,薄膜表面粗糙度与光反射率越大;能量一定,剂量越大导致薄膜光反射率越小。     

数值模拟激光辅助凝聚抑制同位素分离中喷嘴构型对超声速射流的影响

激光辅助凝聚抑制同位素分离(CRISLA)方法需要激光选择性激发超声速射流中的同位素分子，装置内的流场会对分离效果产生影响。CRISLA中超声速射流主要受喷嘴构型的影响，本研究利用计算流体力学(CFD)方法研究喷嘴构型参数(喉部直径、扩张段长度、扩张角度)对CRISLA流动的影响。结果表明，喉部直径是影响射流低温区温度的主要因素，喷嘴扩张段长度对喉部直径3～5 mm喷嘴射流低温区温度影响不明显，而对喉部直径<3 mm的喷嘴射流低温区温度影响较大；喉部直径在3～5 mm时，扩张段长度及扩张角度对射流低温区位置影响小，低温区都位于喷嘴外，喉部直径<2 mm时，扩张段长度与扩张角度对射流低温区位置有显著影响，需要优化二者关系才能在喷嘴外获得较理想射流。在保障低温区位于喷嘴外的前提下，适当增大扩张段角度有利于射流径向扩散。研究的几种喷嘴构型能形成较理想射流，可为未来实验研究提供参考。     

简单可靠的双探针束流剖面仪

本文介绍了步进电机驱动的双探针束流剖面仪。它可以测量强直流离子束中的束流分布。其扫描速度和步长均可调节,并同时记录在X-Y记录仪上。由于采用了步进电机,使得定位准确,重复性好。本文还对探针测量方法作了理论分析,并给出选取探针直径的原则。     

水下地电调查的新方法

本文提出了一种用于水下多层介质视电阻率测量的新技术。这种方法基于直流地电回声测深原理。用一个多层地质模型来模拟地质目标。此测量排列为电极-电极型,电极位于水下,垂直取向。这种特殊的电极设置在不能使用常规电法时尤为有用,尤其是水深时更为重要。计算得出的视电阻率表明由水下目标所引起的被测信号在质量上有很大的提高,而应用传统的地面电极方法所测得的信号很小或者没有反应。实际上,水的分层、水下潜流或气象条件等因素使野外测量结果的解释复杂化。本文展示了在日内瓦湖进行的一个研究实例,使用计算出的视电阻率曲线对野外测量进行了解释。     

Sensitivity analysis of bubble size and probe geometry on the measurements of interfacial area concentration in gas-liquid two-phase flow

Interfacial area concentration measurement is quite important in gas-liquid two-phase flow. To determine the accuracy of measurement of the interfacial area using electrical resistivity probes, numerical simulations of a passing bubble through sensors are carried out. The two-sensors method, the four-sensors method and the correlative method are tested and the effects of sensor spacing, bubble diameter and hitting angle of the bubbles on the accuracy of each measurement method are investigated. The results indicated that the two-sensors method is insensitive to the ratio between sensor spacing and bubble diameter, and hitting angle. It overestimates the interfacial area for small hitting angles while it gives a reasonable accuracy for smaller bubbles and large hitting angles. The four-sensors method gives accurate interfacial area measurements particularly for the larger bubble diameters and smaller hitting angles, while for smaller bubbles and larger hitting angles, the escape probability of bubbles through the sensors becomes large and the accuracy becomes worse. The correlative method gives an overall accuracy for interfacial area measurement. Particularly, it gives accurate measurements for larger bubbles and larger hitting angles while for smaller hitting angles, the spatial dependence of the correlation functions affects the accuracy.     

The first DC performance test and analysis of CC conductor short sample at ASIPP conductor test facility

The first DC performance experiments of ITER correction coil (CC) conductor short sample have been carried out in the conductor test facility of Institute of Plasma Physics, CAS (ASIPP) in January this year. Those experiments aim to investigate the DC performance of ITER CC conductor. The tested conductor short sample is bended as a half circle with the diameter of 270 mm to meet the background magnetic field shape. The half circle part of sample is longer than the final twist pitch. The current sharing temperature (T_cs) in the 3.86 T external magnetic field (B_ex), ≤12 kA could be measured including the critical current (I_c) run. There is no obvious impact of 1000 cycles on DC performance. Those measured T_cs results are in agreement with the expected results from strand scaling.     

蒸汽发生器传热管胀管过渡段水浸超声检查技术

近年来,核电厂提出了对蒸汽发生器传热管胀管过渡段进行检查的要求。由于采用常规涡流检查技术在传热管的胀管过渡段存在盲区,因此开展了传热管胀管过渡段水浸超声检查技术研究,并开发出一套完整的检查技术。通过试验结果分析,证明该技术完全满足蒸汽发生器传热管胀管过渡段检查要求,能够对传统传热管涡流检查形成补充,同时也能够应用于其他薄壁小径管道的检查。      

Application of eddy current inversion technique to the sizing of defects in Inconel welds with rough surfaces

This paper evaluates the applicability of eddy current inversion techniques to the sizing of defects in Inconel welds with rough surfaces. For this purpose, a plate Inconel weld specimen, which models the welding of a stub tube in a boiling water nuclear reactor is fabricated, and artificial notches machined into the specimen. Eddy current inspections using six different eddy current probes are conducted and efficiencies were evaluated for the six probes for weld inspection. It is revealed that if suitable probes are applied, an Inconel weld does not cause large noise levels during eddy current inspections even though the surface of the weld is rough. Finally, reconstruction of the notches is performed using eddy current signals measured using the uniform eddy current probe that showed the best results among the six probes in this study. A simplified configuration is proposed in order to consider the complicated configuration of the welded specimen in numerical simulations. While reconstructed profiles of the notches are slightly larger than the true profiles, quite good agreements are obtained in spite of the simple approximation of the configuration, which reveals that eddy current testing would be an efficient non-destructive testing method for the sizing of defects in Inconel welds.     

Characteristics of Resistive Electrode in MHD Generator Duct and a Minimizing Technique for Internal Power Loss

Two-dimensional current distribution in two regions—resistive electrode and plasma—are studied to optimize the shape of the resistive electrode in the MHD generator. Numerical computations are made for an example of potassium-seeded argon in non-equilibrium. As a first step, the performance is analyzed on an electrode of rectangular shape, and calculations performed more quantitatively than in the previous work by Maxwell et al. reveal that better uniformity is obtained for the current distribution along the electrode surface by increasing the thickness and resistivity of the electrode. The uniformity is found to improve also when the load current is increased.

To diminish the power loss produced in the resistive layer, the electrode shape is optimized by eliminating from the rectangular resistive electrode the portion that produces the power loss. The electrode thus optimized in shape has an effective internal resistance that is independent of the value of the resistivity of the resistive layer. Consequently, in the optimized electrode, the power loss is independent of the uniformity of current distribution along the electrode surface, whereas it depends on the uniformity when a rectangular-shaped electrode is used.     

用于微结构气体探测器的类金刚石碳阻性电极制备研究

通过磁控溅射法制备了用于微结构气体探测器（MPGD）的新型类金刚石碳（DLC）阻性电极,研究了靶电流、真空度、元素掺杂等因素对DLC阻性电极面电阻的影响规律,以及DLC阻性电极结合强度和内应力的优化方法。结果表明：随靶电流的增大,DLC阻性电极的面电阻降低;真空度越高,DLC阻性电极的面电阻越小,稳定性越好;氢元素和氮元素的掺杂使得DLC阻性电极的面电阻增大,且氢元素影响更加明显。本文方法为新构型微结构气体探测器的研发和性能提升奠定了技术基础。     

天光Ⅱ-B装置的诊断刻度

设计并制作了天光Ⅱ-B脉冲功率装置的电流电压诊断设备,根据天光Ⅱ-B脉冲功率装置的同轴传输线结构特点,在传输线末端设置了用于测量负载电压的电容分压器。利用金属膜连接传输线外筒与负载外筒构成回流来测量负载的电流,并利用电路模拟软件对此过程进行模拟,两个诊断探头采取直接标定的方法,测定电容分压器的分压比和回流器的灵敏度。实验结果表明,该探头性能稳定、时间响应快、功率负荷大,是测量脉冲电流与电压的一种理想工具。     

Oxygen Ion Implantation into Indium Phosphate

This paper is the results of oxygen ion implantation on morphological and electrical properties of indium phosphate (InP) semiconductor wafers. The oxygen ions were implanted at 30 keV and various doses in the range between 5 × 10¹⁵ and 5 × 10¹⁷ ions/cm² and at nearly room temperature. The changes in surface roughness and resistivity before and after the implantation is studied using atomic force microscopy (AFM) and four-point probes technique, respectively. The results show that the resistivity is depend on the ion implantation dose. In addition, the RMS roughness of implanted samples dramatically increases by accumulation of oxygen ion dose.     

Positologica: A Positron ECT Device with a Continuously Rotating Detector Ring

A rotary positron emission computed tomography device is developed for human brain and animal studies. The device utilizes 64 rectangular BGO detectors arranged at unequal spacing on a circular ring. The detector ring is continuously rotated at a constant speed of 60 rpm or less. This single continuous motion of the ring with the detector array provides excellent sampling characteristics and high detector redundancy. The device has a field of view 24 cm in diameter with a slice thickness adjustable from 1 cm to 2 cm. Measured width of system response to a 2 mm diameter line source is 5.8 mm FWHM at the center and less than 9 mm FWHM within a circle 16 cm in diameter. Measured sensitivity including scattered coincidence events is about 17 kcps/pCi/ml for a 20 cm diameter water phantom and 2 cm thick slice.     

Measurement and modeling of average void fraction, bubble size and interfacial area

The local void fraction, bubble size and interfacial area concentration for co-current air-water bubbly flow through a horizontal pipe of 50.3 mm internal diameter were investigated experimentally using the double-sensor resistivity probe method. The local and area-averaged void fractions and interfacial area concentrations were analyzed as a function of liquid and gas flow rates. These parameters were found to increase systematically with decreasing liquid flow and increasing gas flow. However, variations with the liquid flow were not as significant as with the gas flow. A consistent variation of the gas phase drift velocity and distribution parameter with the liquid flow rate was observed. It was demonstrated that presentation of the average void fraction in terms of flowing volumetric concentration was more appropriate for horizontal bubbly flow. Several bubble break-up mechanisms were discussed. It was concluded that average pressure fluctuations generated by the turbulent liquid fluctuations acting across a bubble diameter are the only mechanism which causes distortion of a bubble. Based on this force and the competing surface tension force, a theoretical model was developed for mean bubble size and interfacial area concentration. The theoretically predicted mean bubble size and interfacial area concentration were found to agree reasonably well with those measured by the double-sensor resistivity method.