论档案库房温湿度调节与档案的保护与措施

档案是人类社会活动的记录者和承载体,保护档案就是保存和延续人类的记忆。在档案的保管保护中,档案库房温湿度是影响档案材料老化变质的重要因素。本文首先阐述了档案库房温湿度对档案保护的影响,随后根据多年工作经验说明了档案库房温湿度的调节与控制对档案的保护与措施．以及档案人员应该具备的思想素质和专业素质。     

稳频半导体激光器的温度控制技术

设计了一种用于半导体激光器稳频的恒温控制器,在室温下2h的测试时间中,测试恒温稳定度为5mK,配合稳定度为±2μA的恒流源,半导体激光器自由运行时激光频率波动稳定在100MHz范围内。     

浪漫主义艺术家爱因斯坦--纪念狭义相对论创立100周年

本文从叙述滑稽大师卓别林称谓爱因斯坦是一位“浪漫主义艺术家”的轶闻趣事出发，深刻地论证了音乐艺术对物理科学的思维启迪。     

Computation of Bond Dissociation Energies for Removal of Nitrogen Dioxide Groups in Certain Aliphatic Nitro Compounds

Bond dissociation energies for removal of nitrogen dioxide groups in 10 aliphatic nitro compounds, including nitromethane, nitroethylene, nitroethane, dinitromethane, 1-nitropropane, 2-nitropropane, 1-nitrobutane, 2-methyl-2-nitropropane, nitropentane, and nitrohexane, are calculated using the highly accurate complete basis set （CBS-Q） and the three hybrid density functional theory （DFT） methods B3LYP, B3PW91 and B3P86 with 6-31G^＊＊ basis set. By comparing the computed bond dissociation energies and experimental results, we find that the B3LYP/6-31G^＊＊ and B3PW91/6-31G^＊＊ methods are incapable of predicting the satisfactory bond dissociation energy （BDE）. However, B3P86/6-31G^＊＊ and CBS-Q computations are capable of giving the calculated BDEs, which are in extraordinary agreement with the experimental data. Nevertheless, since CBS-Q computational demands increase rapidly with the number of containing atoms in molecules, larger molecules soon become prohibitively expensive. Therefore, we suggest to take the B3P86/6-31G^＊＊ method as a reliable method of computing the BDEs for removal of the NO2 groups in the aliphatic nitro compounds.     

火焰特征辐射谱线测温方法实验研究

本文利用CCD光纤光谱仪,对不同燃烧状态下的煤粉火焰辐射光谱进行测量.发现通过辐射光谱法测量的火焰温度和使用热电偶测量的火焰温度存在一定的偏差.光谱法的温度较热电偶的温度高约60～160℃,沿火焰行程,热电偶和光谱法测量的火焰温度存在较大的特性差异,光谱法测得的火焰温度沿火焰行程基本不变.同时,光谱法火焰温度的高低受到煤质特性,空气湿度,燃烧过程中的散热条件等因素的影响.     

基于模糊神经网络的电气化铁路接触网安全评估

传统铁路接触网的安全评估方法往往只考虑某一个方面的影响,没有综合考虑多个内外影响因素。针对该问题,提出一种基于模糊神经网络的综合安全评估方法。首先建立了一套有效的安全评价指标体系,包括企业管理、人员素质、设备性能以及外部环境4大类该安全评价指标体系能够从主观和客观较为全面地反映铁路接触网的运行管理情况;其次,根据评价指标的特点,采用模糊神经网络算法建立安全评估模型,较好地实现评价指标与安全等级之间的非线性映射。实验结果表明,基于安全评估指标体系所建立的模糊神经网络评估模型,能够很好的对铁路接触网的安全等级做出评估,且评估效果良好。 更多还原     

KIO3晶体的折射率和非线性光学性能

本文在可见光波长范围内测量了未极化的KIO₃晶体的三个不同方向的折射率,用实验方法证实了KIO₃晶体存在Ⅰ尖位相匹配曲面,找到了未极化的KIO₃晶体的最佳位相匹配方向。 关键词：     

佘楞科夫线状发射和类星体光谱

本文讨论了气体介质中的佘楞科夫效应,指出具有各向同性速度分布的相对论电子在稠密气体中运动时,将发生佘楞科夫线状发射,产生具有宽的、轮廓显著不对称的原子发射谱线。其短波边陡直而长波方向则平坦下降。对氢原子L_α线的计算表明,当气休密度达到N=5×10²⁰厘米^-3,L_α线的宽度将大于60埃。根据这一辐射机制,类星体的发射谱线便可得到较为满意的解释。 关键词：     

光学递变介质制法简介

递变介质制法目前有十多种,各类化学气相沉积(CVD)法、补相法(分子填充法、费希尔法)、溶胶—凝胶法、离子注入法、中子轰击法、结晶挤压法、应力法、热离子交换法、场致离子分布法、共聚法、结晶生长法等,其中后四种较为常用。至于各种方法的优缺点,将分别在本文中介绍。     

Polyhedral silver clusters as single molecule ammonia sensor based on charge transfer-induced plasmon enhancement

The unique plasmon resonance characteristics of nanostructures based on metal clusters have always been the focus of various plasmon devices and different applications. In this work, the plasmon resonance phenomena of polyhedral silver clusters under the adsorption of NH₃, N₂, H₂, and CH₄ molecules are studied by using time-dependent density functional theory. Under the adsorption of NH₃, the tunneling current of silver clusters changes significantly due to the charge transfer from NH₃ to silver clusters. However, the effects of N₂, H₂, and CH₄ adsorption on the tunneling current of silver clusters are negligible. Our results indicate that these silver clusters exhibit excellent selectivities and sensitivities for NH₃ detection. These findings confirm that the silver cluster is a promising NH₃ sensor and provide a new method for designing high-performance sensors in the future.