中国环流器二号A(HL-2A)超声分子束注入最新结果

HL-2A装置电子回旋共振加热时,氘脉冲超声分子束穿越分界面,等离子体各项重要参数,包括等离子体储能、极向比压、中平面线平均密度、中心密度和温度上升,中子产额急剧增加. 超声分子束注入有可能较常规脉冲送气在台基顶部提供较强的粒子源,被认为是可供ITER替换脉冲送气的加料方法之一. HL-2A装置氢超声分子束注入的平均速度约为1.7km,与溢流(分子流)注入真空的速度测量作了比较. 关键词： 超声分子束注入 托卡马克 飞行时间法 加料     

盐酸硫胺催化合成乙酰苯胺的新工艺

盐酸硫胺俗称VB1在回流条件下催化乙酰苯胺的合成,反应收率高,副反应少,后处理简单,是一种绿色合成的新工艺.本文研究了该反应的影响因素,结果表明其最佳的反应条件是:苯胺和乙酸的物质的量比为1∶2,带水剂甲苯3mL,催化剂用量占反应物料总量的2 mol％,反应时间为2h,乙酰苯胺收率可达89％.     

频域反射法光纤延时精密测量

本文提出了一种应用于光纤延时系统中实现光纤延时精密测量的新方法,用以提高光纤延时测量的精度和准确性.该方法以1064 nm激光调制信号作为光源,通过测量回波信号的幅值和相位信息得到被测通道的频率响应,采用快速傅里叶逆变换得到被测目标的延时信息,实现光纤延时测量.本文通过理论分析和延时测量实验对频域反射法与传统的时域测量方法进行对比,使用频域反射法在调制频率范围10—200 MHz,采样频率间隔0.5 MHz的实验条件下,实现了3.3 ps延时测量分辨率,并证明了该方法具有比时域方法更高的测量精度,测量结果的准确性更好.     

磁场中简并四波混频的偏振旋转效应

本文讨论了磁场中简并四波混频的偏振旋转效应。计算了J_g=0→J_e=1跃迁的三阶非线性极化率X_yxx⁽³⁾。它包括两个部分:一部分是由于布居差的饱和效应产生的;另一部分是由于原子与光场的相互作用中,感生出来的塞曼相干所造成的。 关键词：     

Multi-Pion Correlations in Two-Pion Interferometry

The influence of multi-pion correlations on two-pion interferometry analysis in multi-pion events can be expressed as the ratio of a multi pion correlation factor for the sample of like-pion pairs to a residual correlation factor for the reference sample.Although these two correlation factors can be partially cancelled our in data analyses,the difference between these two factors in the low relative momentum region is so large that the distortion on the analysed results of two-pion interferometry from multi-pion interference becomes a serious problem when the pion source has a small radius and the pion multiplicity of event is high.The distributions of multi-pion correlation factor C_n－2(q) can sensitively reflect the multi-pion correlation effects in the events The analyses of multi-pion correlation factor for two Bevalac streamer chamber data samples of 2.1AGeV Ne+Pb and 1.8AGeV Ar+Pb collisions show that the multi-pion correlation effect in the former data sample is greater that in the latter.     

Investigation of the limit of lateral beam shifts on a symmetrical metal-cladding waveguide

This paper reports that Goos--H\"anchen (GH) shifts occurring on a symmetrical metal-cladding waveguide are experimentally identified. It was found that there exists a critical thickness of the upper metal layer, h_cr, above which negative shift is observed and, reversely, positive shift occurs. Both positive and negative GH shifts near the critical thickness do not vary dramatically and can achieve a maximum on the submillimeter scale, which is different from simulated results using the stationary-phase method. It also shows that this critical thickness, h_cr, can be obtained at the position for zero reflectivity by setting the intrinsic damping to be the same as the radiative damping. The GH effects observed near the critical thickness are produced by extreme distortion of the reflected beam profiles, which limits the amplitude of the GH shift and, further, the sensitivity of the GH optical sensor based on the symmetrical metal-cladding waveguide.     

模具钢表面激光毛化工艺的试验研究

以模具工业45^#钢摩擦学设计及性能要求为基础,分析了激光毛化模具钢表面形貌的形成机理及其关键的影响因素。采用灯泵浦Nd：YAG脉冲激光器在试样表面进行激光毛化工艺试验,获得了合理的激光毛化参数范围：激光峰值功率0．8～1．6kW,离焦量-1．4～-0．4mm、＋0．4～4-1．4mm,辅助气体压力〉0．2MPa,脉宽1．8ms。采用功率增益和氧气保护,可加工出预先设定的微火山口状毛化形貌。微凹坑形貌的成功获得对于提高拉伸模具的摩擦磨损性能,进一步掌握激光毛化参数与材料的作用规律,提供了有效的数据参考。     

茜素分光光度法测定磷霉素钠

在乙醇体系中,磷霉素钠与茜素发生反应,生成稳定的1∶1的络合物,溶液颜色发生明显改变,其最大吸收波长为545nm,磷霉素钠的浓度在1.4—60mg·L-1范围内遵守比耳定律,表观摩尔吸光系数ε=3.47×103L·mol-1.cm-1,基于以上反应,本方法测定药物制剂含量与文献方法一致,回收率在99.6%—100.5%之间,结果满意。     

高纯锗探测器的广泛应用和自主研制进展

以目前国际上极为活跃开展的暗物质探测、无中微子双 衰变研究为例,评述了高纯锗探测器的重要性及其广泛的应用前景。介绍了己开展的高纯锗单晶、探测器制备的关键技术研究进展:合作单位已研制出了用于高纯锗单晶材料制备的区熔炉、单晶炉;并制备出直径为20  50 cm、纯度为12N(< 41011  atoms/cm3)、位错< 5000 atoms/cm2 的锗单晶;掌握了高纯锗探测器(平面型、同轴型)制备的关键技术,用进口高纯锗单晶材料制备出的同轴型高纯锗探测器对射线的能量分辨率及探测效率均达到进口产品指标,使用自制的12N 高纯锗单晶材料己制备出平面型高纯锗探测器。呼吁加速高纯锗研制的自主创新步伐,尽早实现其国产化目标。The article reviews importance and wide applications of HPGe detector, especially the application on the dark matter search experiment and double beta decay experiment. The research progress on the Highpurity germanium single crystal and HPGe detector in China has been introduced. The cooperation partner developed new type zone-refining furnace and single crystal furnace. The ultra-purity germanium single crystal with 20~50 cm, purity up to 12N(net impurity concentration is less than 41011 atoms/cm3), and dislocation less than 5 000 /cm3 was prepared. The key technologies for preparing planar and coaxial HPGe detector were mastered. The coaxial detector, which has been made of imported ultra-purity germanium single crystal has excellent energy resolution and efficiency as the imported commercial detector. The planar detector using selfmade germanium single crystal was also successfully manufactured. The research group appeals for speeding up the pace of independent innovation on the high-purity germanium, and achieving the high-purity germanium localization as soon as possible.     

Evolution analysis of the states of the EZ model

Based on suitable choice of states, this paper studies the stability of the equilibrium state of the EZ model by regarding the evolution of the EZ model as a Markov chain and by showing that the Markov chain is ergodic. The Markov analysis is applied to the EZ model with small number of agents, the exact equilibrium state for N = 5 and numerical results for N=18 are obtained.