面向大规模数据的在线新事件检测

通过分析基于新闻要素的在线新事件检测算法的时间消耗,提出一种面向大规模数据环境的在线新事件检测算法。该算法利用基于倒排索引的高效相似报道搜索机制,有效减少单路径聚类算法中的相似度比较次数。通过对报道预处理、报道与事件比较以及索引搜索这3个过程的并行化,提高算法在多机环境下的运行效率和可伸缩性。实验结果表明,该算法在不影响漏检率和误检率的基础上,提高了新事件检测的速度,并且在千万到亿级别的报道规模下,其吞吐量达到150条/s~200条/s。     

针翅管滑油冷却器壳侧传热与阻力性能实验研究

以润滑油为换热介质,对1个光管滑油冷却器和3个采用了针翅管的滑油冷却器实验体进行了对比实验研究。结果表明：在本实验范围内,针翅管滑油冷却器的总传热系数较高,是相同条件下光管滑油冷却器总传热系数的1.4～2倍;不同结构针翅管滑油冷却器的传热与阻力性能差别较大,针翅管结构参数和壳侧流程数目是影响滑油冷却器壳程传热与阻力性能的主要因素。实验范围内,较大的针翅高度有利于油流体的扰动,但不利于针翅管一次传热面处的换热;单流程结构的针翅管滑油冷却器具有较高的传热系数和单位体积换热量,其总体换热性能与阻力性能优于双流程结构的针翅管滑油冷却器。     

Measurements of Growth Rate of Filter Cake in Vertical Single-Pass Ultrafiltration Using Hollow Fiber Membrane Module

Vertical ultrafiltration experiments of silica colloid and bovine serum albumin solution were conducted in the single-pass mode by using a hollow fiber membrane module and beneficial in measuring the time evolution of the growth rate of the filter cake during filtration. The extremely small mass flux of the concentrate enabled us to highly concentrate the feed solution on the principle of vertical ultrafiltration in which the filter cake formed on the membrane surface is exfoliated continuously. Both growth and re-entrainment rates of the filter cake formed in vertical ultrafiltration were evaluated from the experimental data of the filtration rate and the mass fraction ratio of the concentrate on the basis of the mass balance within the hollow fiber membrane module. As a consequence, it was found that the re-entrainment rate of the filter cake increased almost linearly with the filtration time in the initial period of filtration and then tended to rapidly approach a constant value. The filter cake stopped growing under this dynamically balanced condition. The variations of the average specific resistance of the filter cake with time were also determined from the time evolutions of both the filtration rate and the growth rate of the filter cake.     

Melatonin-Activated Receptor Signaling Pathways Mediate Protective Effects on Surfactant-Induced Increase in Jejunal Mucosal Permeability in Rats

A well-functional intestinal mucosal barrier can be compromised as a result of various diseases, chemotherapy, radiation, and chemical exposures including surfactants. Currently, there are no approved drugs targeting a dysfunctional intestinal barrier, which emphasizes a significant medical need. One candidate drug reported to regulate intestinal mucosal permeability is melatonin. However, it is still unclear if its effect is primarily receptor mediated or antioxidative, and if it is associated with enteric neural pathways. The aim of this rat intestinal perfusion study was to investigate the mechanisms of melatonin and nicotinic acetylcholine receptors on the increase in intestinal mucosal clearance of ⁵¹Cr-labeled ethylenediaminetetraacetate induced by 15 min luminal exposure to the anionic surfactant, sodium dodecyl sulfate. Our results show that melatonin abolished the surfactant-induced increase in intestinal permeability and that this effect was inhibited by luzindole, a melatonin receptor antagonist. In addition, mecamylamine, an antagonist of nicotinic acetylcholine receptors, reduced the surfactant-induced increase in mucosal permeability, using a signaling pathway not influenced by melatonin receptor activation. In conclusion, our results support melatonin as a potentially potent candidate for the oral treatment of a compromised intestinal mucosal barrier, and that its protective effect is primarily receptor-mediated.     

单摆划痕法及其在材料摩擦磨损方面的应用

单摆划痕法是一种新型摩擦磨损测试方法,它具有动态加载特性,可从力和能量两个方面获得表层材料破坏过程信息。本文介绍了单摆划痕法工作原理及其在常规金属材料的磨损性能、准脆性材料的塑脆转变、复合材料的磨损性能、封严材料的可刮削性、膜-基体系的界面结合强度和表层材料力学性能评价等方面应用,以期进一步拓展其应用领域。     

Effect of anionic macromolecules on intestinal permeability of furosemide

Context: Furosemide is an anionic molecule and has very low absorption in gastro intestinal tract.

Objective: The aim of this study was to investigate the effect of anionic macromolecules on the intestinal permeability of Furosemide.

Materials and methods: The intestinal permeability of Furosemide was determined using single-pass intestinal perfusion technique in rats. Briefly a jejunal segment of ～10?cm was isolated and cannulated in both ends for inlet and outlet solution. The perfusate was collected every 10 min and samples were analyzed using the RP-HPLC method. Test samples containing furosemide and two anionic macromolecules, sodium carboxy methyl cellulose and sodium alginate, at different concentrations were used.

Results: The obtained data showed that existence of Sodium carboxy methyl cellulose significantly increased the P_eff values in all three investigated concentrations (p?Discussion: It is concluded that the anionic macromolecules at specific concentrations could alter the permeability of anionic drugs across the biological membranes.

Conclusions: Donnan phenomenon and chelating property of macromolecules could be attributed to the observed effect.     

单摆划痕仪自动测量系统

为减少人工干预，提高测试精度，研制了单摆划痕仪自动测量系统，包括单摆系统、同步触发系统、测力系统、能耗测量系统、痕槽形貌测量系统和数据处理软件。     

基于改进的 single-pass 网络舆情话题发现研究

舆情监控系统解决的关键问题是如何有效且精确地对文本进行聚类,以便从大量Web网页中发现网络舆情热点话题。single-pass算法是话题发现中最常用的文本聚类算法,但其在文本聚类的精度和时效方面存在不足,因而论文在对大量新闻报道语料进行深入分析的基础上,从三个方面对single-pass进行了改进。通过实验求证,发现改进后的sin-gle-pass算法在漏检率、误检率和耗费函数等方面有了明显改善。     

DP600高强钢板杯形件单道次拉深旋压成形质量分析

为了研究工艺参数对高强钢板杯形件单道次拉深旋压成形质量的影响规律,以旋压件的壁厚分布、直线度以及圆度均值作为评价指标,基于有限元分析软件ABAQUS对DP600高强钢板单道次拉深旋压成形过程进行数值模拟研究,并进行了试验验证。结果表明:在高强钢板杯形件单道次拉深旋压成形过程中,随着旋轮进给比f、旋轮圆角半径rρ以及旋轮与芯模间相对间隙值δ的增大,其壁厚分布的均匀性逐渐变好,直线度逐渐增加;圆度均值呈先减小后增加的趋势,并且均存在一最小值;当f=0.5 mm·r-1、rρ=10 mm及δ=-5%时,DP600高强钢板杯形件单道次拉深旋压成形时的质量最优。     

丙烯腈催化剂除炭再生试验

丙烯腈催化剂因严重结炭而使活性降低。对采用高温焙烧的方法,使其活化再生的工艺条件进行了研究。结果表明,催化剂再生的最佳温度为500℃,时间应超过1．5h。并对带氨活化和不带氨活化的结果进行了比较。催化剂经活化后可使丙烯腈单程收率提高2％～3％。