17N+197Au反应中碎片与中子的符合测量

在3?3?.4MeV/u ¹⁷N束轰击¹⁹⁷Au靶产生的反应中,利用放置于不同角度组合的17个中子探测器(4°—83°)和14个半导体望远镜(2.3°—9.0°)对反应产物碎片与中子进行了符合测量.经对所得实验角分布积分得到Z=3—6元素的同位素产额分布.在参加者-旁观者模型框架下,采用¹⁷N原子核内部的不同密度分布计算了同位素产额分布并与实验数据做比较.     

声化学的崛起与建议

声学对化学的渗透与影响从八十年代中期起开始有了新的转折,表征声学这一外在特性的边缘学科——声化学或曰超声波化学业已形成。从我们跟踪众多国家的研究工作来看,声化学的迅速发展正从学术上给化学研究开拓新的领域;将从应用上对化学工业产生重大影响;声化学与热化学、光化学等具有等同地位的论点日逐扩大。下面列出声化学崛起的一些重要标志:     

非磁杂质对高Tc超导电性的影响

本文证明了在氧化物高T_c超导体的Anderson晶格模型中,由于序参量是能量的函数,非磁掺杂也具有拆对效应,在稀掺杂情况下,求出了T_c随杂质浓度增加而线性下降的规律,与实验结果相符,文中还计算了掺杂对超导态密度中能隙的影响,结果表明,当非磁掺杂浓度增加时,零温能隙的减小比T_c的下降慢得多,从而在转变为正常态之前可能不出现类似通常BCS超导体磁性掺杂的无能隙区。 关键词：     

Monte Carlo studies on the burnup measurement for the high temperature gas cooling reactor

Online fuel pebble burnup measurement in a future high temperature gas cooling reactor is proposed for implementation through a high purity germanium (HPGe) gamma spectrometer. By using KORIGEN software and MCNP Monte Carlo simulations,the single pebble gamma radiations to be recorded in the detector are simulated under different irradiation histories. A specially developed algorithm is applied to analyze the generated spectra to reconstruct the gamma activity of the ¹³⁷Cs monitoring nuclide. It is demonstrated that by taking into account the intense interfering peaks,the ¹³⁷Cs activity in the spent pebbles can be derived with a standard deviation of 3.0%(1σ). The results support the feasibility of utilizing the HPGe spectrometry in the online determination of the pebble burnup in future modular pebble bed reactors.     

INFLUENCE OF SPIN AND CHARGE FLUCTUATIONS ON THE HIGH-Tc SUPERCONDUCTIVITY

In the framework of the weak coupling theory of superconductivity, we have proved that spin and charge fluctuations in the high-T_c superconductors can pro-duce respectively, pair-breaking and pair-forming effects on the superconductivity resulting from the "generalized BCS mechanism". With the coupling constant for spin fluctuations larger than that for charge fluctuations, they combine to produce a temperature-dependent effective pair-breaking effect, which makes T_c decrease more rapidly than Δ(0), the superconducting gap at T=0, and therefore, enhances the ratio 2Δ(0)/T_c. This provides a reasonable physical interpretation for the relevant experimental results.     

一种可编程的高速、高精度、高阶AR滤波器的设计与实现

本文以高速级联型信号处理器IMSA100为基础，构成了一个通用的可编程的硬件结构的AR滤波器．当AR滤波器阶数为1－32阶，参数量化字长为16位时，在全精度运算的情况下，数据吞吐率为2．SMHZ，每秒可完成8千万次乘加运算．此时，输入信号的动态范围最大可达7加E，最高采样率为2．SMHZ，带通、低通滤波器最低带宽的数字频率可达万分之一，过渡带小平0．01．     

30MeV/u 40Ar+112,124Sn反应后角能谱温度的同位旋效应

在30MeV/u ⁴⁰Ar+^112,124Sn反应中用平行板雪崩计数器实现了前冲余核的测量.在不同的线性动量转移下用运动源模型拟合了后角的³He,α和⁶He能谱,发现³He的能谱斜率温度在¹²⁴Sn系统中高于¹¹²Sn系统,而⁶He的温度在¹¹²Sn系统中更高,α粒子在两个系统中没有明显差别.用热核粒子蒸发过程衰变道的选择性对这种同位旋相关性进行了解释.GEMINI的计算不能重现实验结果.     

一种带有陷波单元的高温超导滤波器设计

提出了一种带有陷波单元的新型高温超导滤波器设计结构,在输入、输出馈线附近设置陷波单元对特定频率产生陷波作用,在滤波器的传输特性上成传输零点,提高了滤波器设计的灵活性,基于这种新型结构设计了高边缘陡峭度滤波器和邻频双通带滤波器.     

A rapid and convenient experimental method of absolutely calibrating transmission of x-ray flat-response filter

We develop a rapid and convenient experimental method of absolutely calibrating the transmission of an x-ray flatresponse filter. The calibration experiment is performed on a small laser-target facility, and a set of high resolution holographic flat-field grating spectrometers is used as a discrimination system of the laser-produced x-ray source. Given that the holographic flat-field grating has a relatively large width, the grating is divided into two regions for use in that direction,where one region has the filter added and the other region does not. The filter transmission is determined by dividing the x-ray signal counts detected when the filter is in the line of sight by those detected when the filter is out of the line of sight.We find that the calibration results of this experiment agree with the calibration results using a synchrotron radiation source,as well as simulation results. Our method is not only highly reliable but also rapid and convenient.     

关于使用光谱仪的一些建议

关于使用光谱仪的一些建议肖新民高长连王建模辛建之陶向阳罗宏雷１刘正东２（江西师范大学物理系南昌３３００２７）（１杭州三维高技术产业公司杭州３１００１２）（２浙江大学物理系杭州３１００２７）ＳｏｍｅＳｕｇｇｅｓｔｉｏｎｓｆｏｒＯｐｅｒａｔｉｎｇＳｐｅ...