微机的软件保密

大多数通用微机都存在着一个严重的保密问题。微机通行字对系统编程技术高明的人来说是不起作用的。本文论述了系统的保密取决于文件加密。加密过程全部用软件来实现,并能在不增加微机开销或不增加存贮驻留成本的情况下修改保密程序。     

起重机械虚拟试验技术的研究与展望

虚拟试验是相对于实物试验而言的,由于实物试验存在着若干缺陷和制约因素,因此需要在传统的实物试验中引入新方法,以弥补和完善实物试验的效果和能力.虚拟试验技术起源于航空航天军事工程领域,发展壮大在汽车制造领域,近年来,虚拟试验技术已经在更多的民用行业得到应用.在我国,作为特种设备监管的起重机械,是否有应用该技术的必要性和可...     

基于筛选的新型药物开发方法

近年来,遗传化学和系统生物学的原理都已经关注于药物开发的过程,例如各公司在寻找作为潜在药物的来源以及其他感兴趣的商品化的化合物。本文介绍了一种新型的基于Darwinian筛选原理的平台。     

Single- and few-layer graphene growth on stainless steel substrates by direct thermal chemical vapor deposition

Increasing interest in graphene research in basic sciences and applications emphasizes the need for an economical means of synthesizing it. We report a method for the synthesis of graphene on commercially available stainless steel foils using direct thermal chemical vapor deposition. Our method of synthesis and the use of relatively cheap precursors such as ethanol (CH(3)CH(2)OH) as a source of carbon and SS 304 as the substrate proved to be economically viable. The presence of single- and few-layer graphene was confirmed using confocal Raman microscopy/spectroscopy. X-ray photoelectron spectroscopic measurements were further used to establish the influence of various elemental species present in stainless steel on graphene growth. The role of cooling rate on surface migration of certain chemical species (oxides of Fe, Cr and Mn) that promote or hinder the growth of graphene is probed. Such analysis of the chemical species present on the surface can be promising for graphene based catalytic research.     

Towards Sustainable Neighborhoods:The Role of Social Planning in China-A Case Study of Ningbo,Zhejiang Province

This paper argues for a strengthened form of neighborhood planning designed not only to improve the quality of life but also to promote the social inclusion of disadvantaged groups and a more ecologically sustainable development.Empirical focus is the municipality of Ningbo from 1990 onwards,and the most dynamic dimension of this demographic is the net in-flow of rural migrants from across China,and its implications for social policy are traced.The new infrastructure of local governance affords a unique opportunity for a new approach to solving the critical urban problems of ecological sustainability,social inclusion,and quality of life at the neighborhood level.After showing how neighborhood planners might contribute to local initiatives for neighborhood improvement,the paper concludes with some comments on the implications of this approach for planning education.     

PCB dry and wet weather concentration and load comparisons in Houston-area urban channels

All 209 PCB congeners are quantified in water in both dry and wet weather urban flows in Houston, Texas, USA. Total water PCBs ranged from 0.82 to 9.4 ng/L in wet weather and 0.46 to 9.0 ng/L in dry. Wet weather loads were 8.2 times higher (by median) than dry weather with some increases of over 100-fold. The majority of the PCB load was in the dissolved fraction in dry weather while it was in the suspended fraction in wet weather. Dissolved PCB loads were correlated with rain intensity and highly developed land area, and a multiple linear regression (MLR) equation was developed to quantify these correlations. PCA generated five PCB components with nearly all positive loadings. They were interpreted as DOC-associated A1248, wet weather primarily suspended fraction A1254/A1260 likely from building sealants, truly dissolved-associated wastewater dechlorination, watershed-sourced PCB 11, and monochlorinated PCBs (likely connected to a different state or source of dechlorination). The PCB 11 component was statistically higher in wet versus dry weather when no other component showed such clear distinctions. Hierarchical cluster analysis (HCA) did not always group dry and wet weather samples from the same location together illustrating the different congener composition that often exists between dry and wet conditions. Four wet weather samples from high percentage developed land (> 90%) watersheds had nearly the same fingerprint suggesting a generic “urban” signature in runoff, which in this case was caused by residual A1254/A1260 PCB stocks and currently produced PCB 11 in consumer goods.     

历史悠久的I~2C总线

正如果你认为令人赞叹不已的I2C总线已没有什么新鲜的了,那么让我们摒弃这种观念吧。第一代具有I2C总线功能的集成电路出现于30多年前,1982年由飞利浦半导体公司(Philips Semiconductor)开发,它是简单的串行总线,用于控制电视机内的各种芯片。"I2C总线"代表"内部集成电路总线"。虽然I2C历史悠久,但现在它     

铝及其合金在30～35℃的硬态阳极氧化

一前言铝在阳极氧化过程中生成的氧化膜包含两层,第一层介于膜金属界面之间,该层无孔隙,叫做阻挡层,在恒电压下,阻挡层的厚度在整个氧化过程保持不变. 同时,随着铝表面氧化膜的生成,其外层容易被电解液腐蚀,这一层叫多孔层,它决定了阳极氧化膜的基本特征. 在恒电压情况下,当膜在电解液中的化学溶解速度等于膜的生长速度时,多孔层的厚度达到最大值,膜的极限厚度与工艺条件,电解液组成、温度、电流密度,电压和合金组成有关. 降低电解液的酸度,增加电流密度,并在低温操作下可以生成致密的厚氧化膜,普通阳极氧化液     

自焙电极操作的研究和改进

前言SKW 合金公司是为钢铁、铸铁、铝和化工生产铁合金和添加剂的世界范围厂家。SKW 公司及其在德国、英国、加拿大和美国的子公司生产、销售标准合金和特种合金。在美国的两个生产点位于肯塔吉州卡尔弗特