基于液体静力称量法的纯水密度测量

分析了液体静力称量法测量密度的原理和体积测量中纯水密度的特性公式,推导了由己知密度的固体标准来测量液体密度的计算公式。利用固体密度基准量传装置,通过静力称量法为固体密度标准硅球赋值,其相对测量不确定度3×10^-6(k=2)。在20℃时利用高精度液体密度测量装置,通过静力称量法将固体标准(硅球)密度传递至纯水密度,与Tanaka模型比对,E_n值为0.059,比对结果等效。实验结果不仅验证了高精度液体密度测量装置,还验证了20℃纯水密度模型的理论值。     

Composition and formation of the sleeve enveloping a central venous catheter

PURPOSE: After catheterization, 42% to 100% of central venous catheters are surrounded by a "fibrin sleeve." This sleeve has been considered the cause of catheter-related infections, withdrawal occlusion, and pulmonary embolism. The reactions between the vein wall and the catheter were studied. METHODS: A silicone catheter was placed in the anterior caval vein of 123 rats. After in situ fixation at scheduled intervals, the pathologic changes were studied on semi-serial histologic sections by means of light microscopy, transmission electron microscopy, and scanning electron microscopy (SEM). In 36 rats, the catheter was withdrawn immediately; in 72 rats, it was left in situ up to 6 months; and in 15 rats, the study was performed up to 10 months after withdrawal of a catheter that had remained in situ for 6 months. RESULTS: In the group in which the catheter was withdrawn immediately, mural thrombi disappeared by day 7. In the group in which the catheter remained in situ, thrombi remained around the proximal portion of the catheter. This pericatheter thrombosis (PCT) was invaded by migrating and proliferating smooth muscle cells (SMCs), originating from an injured vein wall, and transformed from day 7 into a tissue composed predominantly of SMCs and collagen and covered by endothelial cells. Later, the number of cells decreased, and the relative amount of collagen increased. Up to 10 months after withdrawal of the catheter, the collapsed sleeve was still present within the vein. CONCLUSION: The sleeve around a central venous catheter is not a fibrin sleeve, but a stable cellular-collagen tissue covered by endothelium. It is mainly formed by smooth muscle cells migrating from the injured vein wall into the early pericatheter thrombus.     

燃烧炉内煤中矿物质行为研究

采用马弗炉和四角燃烧炉对煤中矿物质在加热过程中组分和含量变化利用Ｘ－射线衍射进行分析。结果表明,在燃烧炉内煤灰矿物质行为与在马弗炉内加热煤灰的矿物质行为基本一致;煤灰矿物质行为与原煤中矿物组成及含量关系较大。     

影响结晶化玻璃板材质量因素的分析

研究了烧结法生产结晶化玻璃装饰板材中的气孔、翘板及炸裂产生的原因以及解决的方法。     

科技论文参考文献著录的规范表达

依据ＧＢ７７１４－８７《文后参考文献著录规则》,对３９０篇来稿所引用的参考文献进行统计,分析了几种不规范的著录方式,并给出正确的表达方法,可为科技论文写作者及科技期刊编缉提供参考。     

One-step two-wavelength holography

One-step two-wavelength holography is obtained with twointerferometric beams with different wavelengths by means of apolarizing modulation produced by a liquid-crystal lightvalve. This holographic method eliminates the need for preliminarystatic recording of the hologram and permits one-step two-wavelengthholographic testing to produce results easily in real time.     

配电匹配潮流技术及其在配电状态估计中的应用

针对配电系统的实时量测冗余度低,提出了用配电匹配潮流技术来求解配电技术状态估计的方法,并推导了最优估计意义下的配电匹配潮流方程及其系统化的求解方法,理论分析和算例结果表明,利用配电匹配潮流进行状态估计高效可行,符合当前配电系统在线应用的实际要求。     

Transition from Cassie�CBaxter to Wenzel States on microline-formed PDMS surfaces induced by evaporation or pressing of water droplets

In this work, we directly observed the evolution of air/water interfaces suspended between polydimethylsiloxane (PDMS) microlines when water droplets reduced their sizes due to evaporation. The inclined angles of the microline sidewalls were slightly larger than 90°. Two important phenomena were observed regarding the transition from Cassie–Baxter to Wenzel States. First, when a water droplet gradually shrank, an air/water interface between two neighboring microlines increased its deflection but decreased its angle with the vertical direction. In the meanwhile, the two edges of this interface were still at the top corners of the two microlines. Second, once water passed the top corners of these two microlines, it kept moving down and filled the gap. Based on these two phenomena, the equilibrium of a triple line and the uniformity of pressure inside a small water droplet, critical values of droplet sizes and Laplace pressure were derived to predict when the transition would occur on microlines. The derived theoretical relationships indicate that air/water interfaces may be stationary on both top corners and sidewalls of microlines if the inclined angles of the microline sidewalls are less than 90°. Otherwise, the interfaces can only be stationary at the top corners of the microlines. The predicted values of droplet sizes for the case that the inclined angles of these sidewalls are larger than 90° were validated by experimental results on three arrays of PDMS microlines. In addition, we also directly observed the evolution of air/water interfaces on PDMS microlines when a water droplet was slowly pressed using a glass slide. The critical values of the droplet sizes derived in the case of evaporation applied to this pressing case as well, and had a good match with experimental results on the three arrays of PDMS microlines. In addition to the cases of evaporation and pressing, the theoretical relationships derived in this work may also apply to other cases, in which Laplace pressure is gradually increased inside a liquid droplet and half sizes of the droplet are less than the capillary length of the liquid. Finally, based on developed transition criteria, a set of criteria were also proposed to design microlines for reducing the critical droplet size that triggers the transitions from Cassie–Baxter to Wenzel States.     

钓鱼网页特征向量提取方法研究

随着电子商务和在线交易的增加,网络钓鱼已经成为最严重的一种网络犯罪形式。文章从网页中包含的超链接这一角度出发,给出了网页的身份特征,并结合网页ICP号,版权所有者以及网页行为等对网页特征进行了提取,得到了钓鱼网页的特征向量,为及时准确检测钓鱼网页提供了依据。     

案例驱动下数据结构教材的编写

介绍数据结构的基本概念,讨论对数据结构课程的认知,提出教材编写过程中的几个要点,强调案例驱动教学模式在教材编写中的重要性,从而形成教材自身的特色。