动态社会网络的社团结构检测与分析

真实社会网络如邮件、科学合作、对等网络等均可以用图进行建模. 近年来, 基于图的社团挖掘吸引了人们越来越多的研究兴趣, 它不仅可以帮助识别网络的整体结构, 还可以发现社团演变的隐藏规律. 尽管使用静态图进行社团挖掘已经被广泛采用, 但基于动态图的研究还比较少. 通过使用时间序列, 对动态图上的社团挖掘包括社团检测与分析进行研究, 提出了一个新的动态社团结构检测模型, 并采用真实网络数据集进行了实验. 实验结果显示该模型在社团结构发现的有效性和效率性方面均有着良好的表现.     

西北工业大学举行“礼敬吾师”教师节颁奖典礼

<正>胡沛泉注:感谢严荷女士2014年9月18日自西工大新闻网下载重要的西工大举行"礼敬吾师"教师节颁奖典礼。作者:吴秀青,郭友军。来源:宣传部。发布时间:2014年09月11日。严女士点击为第7361次。本简讯摘录的内容如下:西工大新闻网9月11日电(记者吴秀青摄影记者郭友军)金秋九月,第30个教师节带着秋的神韵向我们走来。在这个特别值得纪念的日子里,亲爱的老师,让我们把最美好的祝福献给您!把最诚挚的感谢献     

Morphology,crystal structure and hydration of calcined and modified anhydrite

The effects of calcination and modification on the morphology （shapes and textures） and crystal structure of anhydrite powders were studied. The results show that, calcination at 100℃ causes anhydrite to disintegrate into smaller crystals, accompanied by a slight in- crease in d-spacing. Without calcination and modification, the solidification time and curing time of anhydrite are 15 and 77 h, respectively. After the treatment, however, the solidification time and curing time are shortened significantly to 9.5 and 14 rain, respectively. The com- pressive and flexural strengths of hydration products made from the treated anhydrite reach 10.2 and 2.0 MPa, respectively. The much shorter solidification and curing time make it possible to use anhydrite as a building and construction material.     

Liquefaction of metal-contaminated giant reed biomass in acidified ethylene glycol system： Batch experiments

Giant reed is a suitable pioneer plant for metal-contaminated soil phytoremediation,however,it is imperative to dispose the metal-contaminated biomass after harvesting.The liquefaction of metal-contaminated giant reed biomass in ethylene glycol system with sulfuric acid as catalyst for the precursors of polyurethane compounds was studied.The results show that giant reed biomass from metal-contaminated soil is potentially liquefied and significantly affected by solvent/solid ratio,liquefaction temperature and liquefaction time （P〈0.05）.The liquefaction rate of biomass in acidified ethylene glycol system can reach 85.2% with optimized conditions of 60 min,170 ℃,3% sulfuric acid and solvent/biomass ratio of 5：1.The hydroxyl value of liquefied products is of 481 mg KOH/g while reactive hydroxyl groups of them are abundant,which is promised as potential precursors for polyurethane compounds.The solvent liquefaction is a potential method to dispose the metal-contaminated biomass,however,the containing-metal liquefied products should be studied deeply in order to get the suitable precursors in future.     

Optimal paths planning in dynamic transportation networks with random link travel times

A theoretical study was conducted on finding optimal paths in transportation networks where link travel times were stochastic and time-dependent（STD）. The methodology of relative robust optimization was applied as measures for comparing time-varying, random path travel times for a priori optimization. In accordance with the situation in real world, a stochastic consistent condition was provided for the STD networks and under this condition, a mathematical proof was given that the STD robust optimal path problem can be simplified into a minimum problem in specific time-dependent networks. A label setting algorithm was designed and tested to find travelers＇ robust optimal path in a sampled STD network with computation complexity of O（n2＋n·m）. The validity of the robust approach and the designed algorithm were confirmed in the computational tests. Compared with conventional probability approach, the proposed approach is simple and efficient, and also has a good application prospect in navigation system.     

NAND Flash service lifetime estimate with recovery effect and retention time relaxation

A service life model of NAND flash and threshold voltage shift process is proposed to calculate the service life and endurance. The relationships among achievable program/erase （P/E） cycles, recovery time, bad block rate and storage time are analyzed. The achievable endurance and service life of a NAND flash are evaluated based on a flash cell degradation and recovery model by varying recovery time, badblock rate, and storage time. It is proposed to improve the service lifetime of solid state disk by both relaxing the bad block rate limitation and retention time while extending the recovery time. The results indicate that endurance can be improved by 17 times if the storage time guarantee is reduced from 10 a to 1 a with 10 5 s recovery time inserted between cycles.     

Adsorption behavior of cross-linked chitosan modified by graphene oxide for Cu（Ⅱ） removal

Cross-linked chitosan（CS）,cross-linked chitosan/graphene（CS/RGO10） and cross-linked chitosan/graphene oxide（CS/GO10） were prepared as adsorbents for Cu（Ⅱ）.The effects of pH,contact time,adsorbent dosage and initial concentration of Cu（Ⅱ） on the adsorbing abilities of CS,CS/RGO10 and CS/GO10 to Cu（Ⅱ） were investigated.The results demonstrate that the adsorption capacities of CS/GO10 and CS/RGO10 are greater than that of CS,especially at pH 5.0 and the adsorption capacities are 202.5,150 and 137.5 mg/g,respectively.Their behaviors obey the Freundlich isotherm model very well.Additionally,CS/GO10 has the shortest time to achieve adsorption equilibrium among them and can be used as a perspective adsorbent for Cu（Ⅱ）.     

基于ExtendSim的VSI均值控制图改进方法

利用ExtendSim仿真实验对VSI均值控制图的实施过程进行模拟,得到了VSI均值控制图相关性能指标的仿真实验结果。通过分析仿真实验结果与理论计算值之间的误差,指出ExtendSim所模拟的抽样过程更符合实际生产的操作习惯,因而其结果更加具有参考性。考虑到VSI均值图对较小的均值偏移反应不够灵敏,提出了一种改进的VSI均值控制图,利用ExtendSim仿真实验得到该均值控制图的相关性能参数。实验结果表明,改进的VSI均值控制图相对于一般VSI均值控制图具有更好的工作性能。     

多孔碳板气-气增湿器新型设计方法

多孔碳板是一种具有高孔隙率和高导热性能的多孔材料,适合制作燃料电池增湿器,针对这一特性,提出了一种多孔碳板气-气增湿器的基本结构,以停留-扩散时间比和流道内气体流速为设计依据,提出了多孔碳板气-气增湿器的优化设计流程。通过优化设计,使增湿器在燃料电池所需气体流量的条件下工作时,停留-扩散时间比与气体流速均在一定范围之内,既保证增湿器的增湿效率较高,又保证增湿器体积不至于过大。根据该设计方法为一个25 kW燃料电池系统设计了多孔碳板气-气增湿器,能满足增湿要求。     

一般空间对象的空间数据类型

空间数据类型的定义一直是空间数据库和GIS等领域的研究热点.针对一般空间对象的空间数据类型定义问题,依据点集和拓扑理论,采用函数方法,研究了一般空间对象的特点,并给出了一组有效时间内的一般空间对象的带时间维的空间数据类型定义,包括一般点,一般线,一般区域.一般空间对象的空间数据类型定义将一般点定义为多个单点的并集;一般线定义为多个连续函数的并集;一般区域定义为多个面的并集.在一般空间对象的空间数据类型基础上,可建立一般空间对象的数据模型,一般空间对象的空间关系,从而在空间查询中,能处理针对一般空间对象的空间查询.