145Er的β延发质子衰变性质研究

通过92Mo(58Ni, 2p3n)熔合蒸发反应生成了非常缺中子核145Er。利用氦喷嘴带传输系统把研究目标核传输到低本底测量站, 进行了质子 γ符合测量, 得到了不受同量异位素干扰的145Er的β延发质子谱。经过仔细分析与延发质子符合的γ谱, 发现了145Er的11/2-同核异能态具有β延发质子衰变性质。经拟合退激144Dy不同激发态γ跃迁的衰变曲线, 得出145Er的1/2+基态和11/2-同核异能态的半衰期分别为(1.6±0.6)和(0.6±0.1) s。最后, 简单介绍了中重质量区缺中子新核素的合成及衰变研究计划。The neutron deficient isotope 145Er was produced via the fusion evaporation reaction 92Mo(58Ni, 2p3n). The reaction products were transported to a low background counting area using a He jet tape transport system, and proton γ coincidence measurements were carried out. Based on the analysis of γ transitions in coincidence with β delayed protons, the β delayed proton decay of an νh11/2 isomer in 145Er was proposed. By fitting the decay curves of the γ transitions depopulating the low lying states in 144Dy, the half lives of the ground state and the νh11/2 isomeric state in 145Er were deduced to be (1.6±0.6) and (0.6±0.1) s, respectively. An experimental plan to synthesize new β delayed proton precursors in the medium heavy mass region has been presented.     

基于阵列式连体透镜的LED二次光学设计

针对LED照明系统中单颗LED及其透镜组合设计的发光量小,照射范围有限,不能满足实际照明需求的问题,提出了一种阵列式连体透镜的LED二次光学设计.根据阵列式LED的特性建立多颗了LED光学模型,并运用光学仿真软件TracePro对该二次光学设计进行模拟与仿真.结果表明,阵列式连体透镜在改善光照均匀性方面具有较好的效果,...     

Study of the THGEM detector with a reflective CsI photocathode

The THGEM detector without and with a CsI has been tested successfully. The optimal parame- ters of THGEM have been determined from eight samples. The UV photoelectric effect of the CsI photocathode is observed. The changing tendency related to the extraction efficiency (ε<,extr>) versus the extraction electric field is measured, and several electric fields influencing the anode current are adjusted to adapt to the THGEM detector with a reflective CsI photocathode.     

A study on odd-parity high-lying states of the Sm atom with three-color resonant excitation

The odd-parity high-lying states of the Sm atom are investigated systematically by a three-color resonant excitation scheme with two different excitation paths.The two intermediate states,4f 6 6s7s 7 F 0 and 4f 6 6s7s 7 F 1 are employed for paths I and II,respectively.Fifty-seven bound states are detected with paths I and II in the energy range between 44188 and 45515 cm 1,while 64 autoionizing states are found in the energy range from 45528 to 45761 cm 1.Not only the level energies of all observed states,b...     

Research on a novel compact linac

This work looks at a new type of electron linear accelerator.Compared with the traditional electron linac,it has only two main parts:a klystron and an accelerating tube,without the electron gun element.This new kind of linac could perform just like its predecesors but reduce cost and space.The preliminary design and simulation have been accomplished.In this paper,an overview discussion about the performance tests and some improvements to increase the beam current are presented.     

干涉测量用半导体激光器驱动电源

设计了一种可调制的高稳定度半导体激光器驱动电路。该电路的直流稳定度高达1.5×10-5，输出电流在0～200mA内连续可调，长时间工作（12h以上）电流变化小于1μA；在直流基础上注入100kHz～300kHz的调制电流，其调制深度为0～100mA连续可调，可实现在激光干涉测量中对光波频率和光波强度的调制。将该电路驱动的光栅外腔半导体激光器和辅助温度控制电路应用于光干涉测量技术中，得到了功率稳定、波长单一的激光输出，解决了激光器的跳模现象，完成了对远距离微小振动（纳米量级）的测量。     

三个热力学偏导数()、()和()等于系统化学势的又一证明方法

对三个热力学偏导数()、()和()等于系统化学势给出了又一种证明方法.     

高效传热管内凝结换热性能及阻力性能的实验研究

本文以ＨＦＣ１３４ａ和ＨＣＦＣ２２为工质对光管及两种不同槽型的强化传热管（ＤＡＥ－２管与ＤＡＥＣ管）的水平管内凝结换热进行了对比实验研究、研究发现,ＤＡＥ－２管平均换热系数比光管提高了１４０％～１７０％,而单位长度阻力损失增加了５０％～１００％,ＤＡＥＣ管平均换热系数比光管提高了１６０％～２００％,同时单位长度阻力损失增加了７０％～１３０％。此外,本文给出了ＤＡＥ－２管和ＤＡＥＣ管平均换热系数及阻力损失的计算关联式,可用于冷凝器设计。     

高等院校创新人才培养模式的探索与实践

培育创新型、德才兼备型、且具有较高实践能力的人才,是各高等院校多年来常抓不懈,实践探索的重心.西安电子科技大学在以培养基础扎实、知识面宽、能力强、素质高的创新型人才为核心目标的基础上,固本促创新,进一步转变人才培养观念,树立先进的教育理念.探索基于"研究-实践-创新"的人才培养模式,设计"两层四类"的实践创新结构,更新了实践教学观念,丰富了实践教学体系,进一步引导学生尽早参加科研和创新活动,使更多的大学生从中受益,并在实践动手能力与创新能力方面得到更好的提高.     

银河杜仲沼液种植3层目标轮换6级储存网络系统设计

由农村沼气工程引起的规模养殖沼液二次污染问题是当前农村环境污染治理的重点问题,也是牵制农业产业化发展,影响中国特色农业现代化道路的关键矛盾。运用最大流和最小饱和流理论,以消除江西银河杜仲绿色规模养殖基地的二次污染为研究对象,对沼液输送浇灌净化工艺流程进行了3层6级储存网络设计分析,给出了解决规模养殖沼液二次污染矛盾,实现沼液零污染最小排量问题的有效方法。