Dried jujube classification using support vector machine based on fractal parameters and red,green and blue intensity

A new method that combines fractal theory and red, green and blue (RGB) colour intensity was developed to sort dried jujube fruits by using support vector machine (SVM). Our result shows that the new method is fast and accurate in dried jujube fruits classification. The SVM models based on fractal parameters only achieved 85.18–92.73% total accuracy rate. The total classification accuracy of SVM based on RGB intensity values was 94.44%. However, the SVM models based on combining fractal parameters with RGB intensity values achieved 94.44–98.15% total accuracy rate. The best classification accuracy (98.15%) was found when using SVM model based on combining fractal measures (FM) with RGB intensity values (C = 512, γ = 0.0078125). Therefore, the SVM model based on combining FMs with RGB intensity is recommended in dried jujube fruits classification.     

SQL注入攻击及防御技术的研究

近年来,SQL注入攻击成为黑客攻击网站获取信息的主要技术手段,网站管理员要有效防御攻击就要了解SQL注入攻击的方法并采取相应的措施进行防御。就SQL注入攻击技术、SQL注入攻击的防御及基于ISAPI过滤器的防御系统进行了详细的研究,为有效防御SQL注入提供了方法及手段。     

城市湖泊型湿地公园景观营建研究——以东湖国家湿地公园为例

该文以武汉市东湖国家湿地公园为研究对象,通过对东湖国家湿地公园的现状调查,结合湿地公园景观营建相关资料,分析了东湖国家湿地公园与武汉市及东湖风景区的关系,阐述了东湖国家湿地公园中景观构成要素的营建方式。在此基础上,归纳了城市湖泊型湿地公园的特性,并分别从植被、湖岸带、水环境及人工设施等方面分析探讨城市湖泊型湿地公园景观营建方法。通过对东湖国家湿地公园的景观营建分析及城市湖泊型湿地公园景观营建方法的探索,为完善东湖湿地公园建设及城市湖泊型湿地公园景观营建提供指导策略及参考。     

摇床T25细胞培养瓶流体力学与传质特性研究

细胞培养技术是生物医药产业的支柱,以实现微小体积内的高密度、高通量细胞培养为目的,系统地研究了常用于单层静态培养的T25方瓶置于翘板摇床上在不同操作条件下的流体力学特性和传质性能。结果表明,振荡可以显著提高方瓶的传质速率并降低混合时间,使高密度培养成为可能,但瓶盖上的空气滤膜在高转速时成为传质速率的限制因素;培养瓶对称轴与摇床旋转轴平行时,其相对位置对混合和传质无明显影响,但当二者成45°角时,相同转速下混合时间显著缩短;使用自定义函数实现了基于动态网格的CFD模拟,对不同转速下方瓶内剪切应力和能量耗散在时间与空间上分布进行了分析,为基于T25培养瓶开发一次性高通量微型反应器提供了数据支持和理论基础。     

Toward an understanding of how red phosphorus and expandable graphite enhance the fire resistance of expandable polystyrene foams

Flame retardant expandable polystyrene (EPS) foams were prepared by coating method. Red phosphorus (RP) and expandable graphite (EG) were chosen as the flame retardants to be coated on the surface of expanded PS beads. By the presence of 33 phr RP/EG with a mass ratio of 1:1, the limiting oxygen index of EPS foam could reach up to 26.9%, with V-0 rating obtained in UL-94 test. The peak heat release rate could also decrease to 180.67 kW/m², which was 72.9% lower than that of neat EPS sample. Thermogravimetric analysis revealed an obvious increase of thermal stability and residue char amount by the presence of RP and EG. From the observation and analysis of char residue, it could be proposed that there existed a significant synergistic effect between RP and EG. RP could be oxidized and further react with graphite by the presence of oxygen at high temperature, forming isolated char layer and releasing nonflammable gases. Moreover, P radicals were generated at high temperature and could capture the radicals formed during the combustion of polystyrene and eliminate the burning chain reactions.     

螺旋焊管波浪压痕的消除

简要介绍和分析了螺旋焊管生产过程中产生的波浪压痕及其成因,并给出了消除方法。通过生产实践证明,在螺旋焊管生产过程中,经过理论计算,只要能准确地给出成型器1～3号微型辊组的位置参数,就能够消除焊管管体的波浪压痕。     

Native point defects and oxygen migration of rare earth zirconate and stannate pyrochlores

Various excellent properties of rare earth zirconate and stannate pyrochlores are close related with their native point defects.First-principles calculations are performed to systematically investigate the point defect mechanism and the oxygen diffusion behavior of A2B2O7 (A=La,Ce,Pr,Nd,Pm,Sm,Eu,Gd;B=Zr,Sn).The possible defect complexes and their associated reactions under stoichiometric and nonstoichiometric conditions are explored.The O Frenkel pairs are the most stable defect structure in stoichiometric zirconates,whereas the cation antisite defects are the predominant one in stoichiometric stannates.In the case of BO2 excess zirconates and stannates,the BA cation antisite defect with the A vacancy and/or the oxygen interstitial is energetically favorable,whereas the AB antisite defect together with the oxygen vacancy and/or the A interstitial is preferable under the A2O3 excess condition.Meanwhile,the maximum point defect concentrations of zirconates are much higher than those of stannates.Furthermore,the oxygen migration barriers are similar in these compounds,ranging in 0.68 eV-0.80 eV.The predicted point defects and oxygen diffusion mechanisms play the critical role in their engineering applications and are expected to guide the future property improvement of pyrochlores through the control of point defects and/or composition.     

一种移动Agent通信协作模型

基于FIPA ACL和Linda协作模型的思想和方法,提出一种移动Agent通信协作模型Wagent模型。这种通信协作模型结合了FIPA ACL和Linda协作模型各自的优点,解决基于语义的协作和移动Agent的通信失效问题。在IBM的Aglet平台上,实现这种通信协作模型。     

基于不同测井曲线的煤体结构识别 ——以大同煤田塔山矿为例

为探究大同煤田塔山矿3～5号煤层煤体结构特征及对应的测井曲线识别方法,以塔山矿50余口钻孔数据和测井结果为研究依据,通过测井曲线解释、构造煤煤体结构指数和原生煤比例计算等数学方法结合,进行构造煤发育特征的定性和定量分析,并绘制塔山矿构造煤平面展布规律图.结果表明:塔山矿3～5号煤层在测井曲线上表现为高电阻率、高声波时差...     

以风化煤为底物制取生物甲烷的潜力分析

我国拥有丰富的风化煤储量,因其高度被氧化的独特性质,可应用的领域极为有限,目前主要被作为改善土壤性质的肥料和制取腐殖酸的来源。以风化煤为底物制取生物甲烷是一种具有探索性的全新生物发酵工艺,探究其可行性及模拟实验过程中风化煤的物性特征变化有利于拓宽风化煤的资源利用和环境改善,并可以进一步丰富煤生物产气理论。实验选取内蒙古乌海和山西晋城两地不同风化程度煤样,以煤层矿井水为菌种来源,在适宜环境条件下开展模拟产气实验,通过生物产气模拟和红外光谱测试,分析不同风化程度煤的生物产气能力及其内在因素,以揭示其产气潜力及物性变化特征。结果表明:①随着煤的风化程度加深,可燃基CH 4产气量明显增加,两组煤样中可燃基CH 4生成量最高分别达到7.13,4.20 mL/g;②不同风化程度的煤样均出现了产气高峰,时间基本都出现在15~30 d,各组中随着煤样风化程度不断加深,产气高峰出现时间也越来越早;③随着煤的风化程度加深,煤中芳环被不断打开,大分子结构被破坏,同时煤中羟基、氨基等基团含量趋于降低,脂碳结构逐渐解体,含氧官能团成为主要结构,氧含量比例不断增高,更容易被微生物降解;④菌群鉴定表明风化煤不仅含有大量产生生物气所需的第1阶段和第2阶段细菌,更含有甲烷杆菌属、甲烷球菌属等多种类型的产甲烷菌群,具有把风化煤转化为生物甲烷的环境条件。实验结果最终反映了风化煤具有转化为生物甲烷的潜力,并有利于提高我国风化煤的资源利用率。