等级保护思想的演化

信息安全等级保护是中国正在大力推行的一项制度。等级保护思想起源于美国军方的安全保密制度,随着计算机的广泛使用和网络时代的到来,等级保护不断被注入新的内涵。今天,等级保护已经不仅仅是一种技术思想,而是发展成为贯穿信息安全保障各个环节的一个过程和一种制度。追溯了等级保护思想的源头与发展历程,并探讨了建立在等级保护思想之上的信息安全标准体系。     

微腔中nc-Si/SiN超晶格的光致发光

研究了一维光子晶体微腔结构对nc-Si/a-SiNz超晶格发射的调制.一维光子晶体微腔采用两种具有不同折射率的非化学组分非晶氮化硅的周期调制结构,腔中嵌入采用激光晶化方法制备的硅量子点阵列,从Raman谱和透射电子显微镜分析得到其尺寸约为3～4 nm.从光致发光谱上观察到明显的选模作用、明显变窄的发光峰以及约两个量级的发光强度的增强.微腔对硅量子点阵列发光的调制主要表现在两个方面:共振模式的增强和非共振模式的抑制.硅量子点中位于腔共振模式的辐射跃迁被增强,非共振模式的辐射跃迁被抑制,因此位于腔共振频率处的跃迁通道成为硅量子点中唯一的辐射跃迁通道,导致光致发光谱的窄化和强度的增强.因此,在提高硅材料发光效率方面,光子晶体微腔具有非常大的应用前景.     

广西某铀矿流出物和周围水体放射性水平现状监测及评价

铀矿石中可提取到镭、铀和其他稀土元素,广西的铀矿资源较为丰富,被核工业称为“开业之石”的新中国第一块铀矿既产自广西贺州市。某放射性铀矿开采和水冶企业位于广西境内的车田乡与瓜里乡交界地带的沙子江,该矿项目已于2016年停产,矿井口封闭并处于淹井状态,堆浸及水冶也全面停止,但以废水处理为主的环保设施仍维持运行正常。对该铀矿停产后进行长期水体和流出物放射性监测,发现水中各监测断面的各类放射性核素活度浓度在历年涨落范围内,各放射性指标符合相关行业标准,可初步分析停产后环保设施运行情况是否正常,初步判断停产后矿区对周围水体是否存在放射性影响。     

Ti/NiCu/Ag and Al/NiCu/Ag thin film deposited on positive temperature coefficient (PTC) thermistor by direct current magnetron sputtering

Metallization of positive temperature coefficient (PTC) thermistors deposited by direct current magnetron sputtering has been investigated. Two kinds of multilayer thin films, namely Ti/NiCu/Ag and Al/NiCu/Ag, are proposed as electrode materials. Conventional NiCr/Ag thin film serves as reference electrode in the experiment. Experimental results show that the newly proposed electrodes exhibit good performance including low ohmic contact, firm adhesion, fine solderability and stability. The surface resistances at room temperature of Ti/NiCu/Ag and Al/NiCu/Ag PTC range from 4.3 to 6.2 Ω, and they change little in moisture condition. The average tensile strength is 6.3 Mpa, which provides firm adhesion between electrode and substrate. At solderability test, the new electrodes can withstand the soakage of lead-free solder at 350 °C for 5 s and the properties remain stable after high temperature treatment.     

环形支撑在不规则形状深基坑支护中的应用

结合工程实例,论述了环形支撵在不规则形状深基坑中的应用,并且采用环形支撑很好地控制了基坑变形,方便了土方开挖和基础施工.这对类似工程具有参考意义.     

人工神经网络方法在优化动力配煤中的应用研究

对神经网络ＢＰ算法的一些改进作了大量的数值试验研究，并组合了部分改进方法用于动力配煤问题中状态预测过程的建模，最后把神经网络方法纳入到非线性混合离散变量优化设计方法（ＭＤＯＤ法）中，对杭州配煤场 动力配煤过程作了应用介绍。     

几种国产聚丙烯透明成核剂性能的研究

研究了采用国产三代山梨醇透明成核DMDBS制备的透明聚丙烯的光学性能、结晶性能、机械性能与热性能。研究表明,在0~2500ppm内随着添加量的增加,国产三代山梨醇透明成核剂与美利肯3988i具有相似的浊度变化曲线。在同样的添加量下,国产三代山梨醇透明成核剂具有与3988i相近的光学性能、结晶性能、机械性能与热变形温度,且无气味,可作为替代进口透明剂、降低生产成本的有效途径。     

丰满水电站3号机尾水管加固改造设计

本文主要叙述了丰满水电站3号机尾水管加固改造设计;主要包括尾水管旧混凝土的检测、凿除,新尾水管的结构设计、施工等。     

A novel coumarin‐based fluorescent probe for selective detection of cysteine over homocysteine

A coumarin‐based fluorescent probe containing both acrylate moiety and an allyl substituent was developed for distinguishing cysteine from homocysteine. The maximum absorption wavelength of the probe showed a bathochromic shift upon addition of cysteine and the colour changed from colourless to yellow. The maximum fluorescence emission at 462 nm of the probe was dramatically enhanced upon addition of cysteine in aqueous solution. In HEPES buffer (pH = 7.4, EtOH/H₂O = 9:1, v/v), both of the fluorescence emission bands of the probe at ca. 390 and 462 nm were intensely enhanced upon the addition of cysteine, while other amino acids, namely, homocysteine, asparaginic acid, methionine, glycine, phenylalaninase, valine, tryptophan, serine, glutamic acid and glutathione, did not cause a remarkable change. The probe can be used for selectively colorimetric and ratiometric fluorescent detection of cysteine over homocysteine and other common amino acids in both organic media and aqueous solution. The concentration of cysteine can be estimated by titration of the probe in aqueous solution, and the detection limit of the probe towards cysteine was 2 μmol/L.     

生丝练减率测试取样方法的实验研究

为了确定练减率测试样丝的取样方法,对练减率测试样丝抽取方法开展了比对实验研究,实验结果表明,从25绞品质样丝中卷取的练减率测试样丝,具有检测结果稳定、样本量检测成本低等优点.