用过零时间法分析的中能重离子探测器望远镜

本文描述了中能重离子探测器望远镜ＮＥ１０２Ａ＋ＣｓＩ（Ｔｌ）＋ＰＭＴ采用过零时间的方法鉴别粒子，实验结果表明可清楚地分辨ｐ、ｄ、ｔ同位素和探测到的全部碎片。     

采用基因表达式编程的沟灌入渗模型参数估计方法

入渗参数的准确估计是沟灌系统设计优化的关键问题。本文基于基因表达式编程(GEP)算法,通过数值试验获得了沟灌入渗模型参数γ估计GEP算法所需的有效数据集合,进行了参数γ的敏感性分析,确定了模型参数γ估计GEP算法的输入因子及其最优组合,建立了γ与最优组合因子的定量关系,进而提出了γ的估计方法。研究结果表明,γ对积水深度、初始有效含水率和沟深度最敏感;土壤水力特性参数对γ影响较大,模型参数γ估计GEP算法的最优输入因子组合为积水深度、沟深、初始有效含水率、饱和导水率和进气值参数;变积水深度条件下γ的估计值与定积水深度的γ值相近;在变积水深度条件下,与利用HYDRUS-2D模型计算得到的"精确"入渗量相比,应用基于γ估计值的沟灌入渗模型计算的累积入渗量误差小于5%,满足计算精度要求。入渗过程中边界效应对总入渗量的贡献逐渐增大,与细质土壤相比,粗质土壤中边界效应对总入渗量的贡献更大,本研究条件下黏壤土中边界效应最终贡献约为25%,砂土中约为37%。研究表明GEP算法可作为沟灌入渗模型参数γ估计的一种有效方法。     

Peri-Watchdog: Hunting for hidden botnets in the periphery of online social networks

In order to evade detection of ever-improving defense techniques, modern botnet masters are constantly looking for new communication platforms for delivering C&C (Command and Control) information. Attracting their attention is the emergence of online social networks such as Twitter, as the information dissemination mechanism provided by these networks can naturally be exploited for spreading botnet C&C information, and the enormous amount of normal communications co-existing in these networks makes it a daunting task to tease out botnet C&C messages.Against this backdrop, we explore graph-theoretic techniques that aid effective monitoring of potential botnet activities in large open online social networks. Our work is based on extensive analysis of a Twitter dataset that contains more than 40 million users and 1.4 billion following relationships, and mine patterns from the Twitter network structure that can be leveraged for improving efficiency of botnet monitoring. Our analysis reveals that the static Twitter topology contains a small-sized core sugraph, after removing which, the Twitter network breaks down into small connected components, each of which can be handily monitored for potential botnet activities. Based on this observation, we propose a method called Peri-Watchdog, which computes the core of a large online social network and derives the set of nodes that are likely to pass botnet C&C information in the periphery of online social network. We analyze the time complexity of Peri-Watchdog under its normal operations. We further apply Peri-Watchdog on the Twitter graph injected with synthetic botnet structures and investigate the effectiveness of Peri-Watchdog in detecting potential C&C information from these botnets.To verify whether patterns observed from the static Twitter graph are common to other online social networks, we analyze another online social network dataset, BrightKite, which contains evolution of social graphs formed by its users in half a year. We show not only that there exists a similarly relatively small core in the BrightKite network, but also this core remains stable over the course of BrightKite evolution. We also find that to accommodate the dynamic growth of BrightKite, the core has to be updated about every 18 days under a constrained monitoring capacity.     

产品形象本土化创意思考

本文通过引入产品形象设计的概念和方法,对国内外部分知名企业的产品形象进行对比,帮助本土企业建立产品形象意识,解决产品风格的不稳定性,在同一系列产品中建立区别和联系,同时帮助企业建立与其它企业同种类产品不同的形象特征,从而改善市场中形式风格的混乱。     

GPU加速的圆弧轨迹Katsevich锥束CT重建算法

通过改进GPU的渲染到纹理策略加速锥束反投影计算,提高了圆弧轨迹Katsevich锥束CT重建算法的执行效率.在CPU中完成投影数据的滤波处理,并将其重排为四通道浮点纹理载人GPU内存;绑定2个浮点输出纹理到帧缓冲对象的不同绑定点,用于将渲染结果输出到纹理,并同时完成反投影数据的累加计算;将矩形网格编码为四叉树结构用于加速物体切片的绘制.实验结果表明,文中算法在较大锥角时仍能重建出高质量图像,并获得接近于实时的重建速度.     

RADIOIMMUNOTOXICOLOGICAL EFFECT OF ENRICHED URANIUM ON CENTRAL AND PERIPHERAL IMMUNE CELLS AND THE PROTECTIVE ACTION OF IL－1 AND IL－2

ＲＡＤＩＯＩＭＭＵＮＯＴＯＸＩＣＯＬＯＧＩＣＡＬＥＦＦＥＣＴＯＦＥＮＲＩＣＨＥＤＵＲＡＮＩＵＭＯＮＣＥＮＴＲＡＬＡＮＤＰＥＲＩＰＨＥＲＡＬＩＭＭＵＮＥＣＥＬＬＳＡＮＤＴＨＥＰＲＯＴＥＣＴＩＶＥＡＣＴＩＯＮＯＦＩＬ－１ＡＮＤＩＬ－２￥ＺｈｕＳｈｏｕｐｅ...     

酚羟基修饰吸附树脂对2-萘酚的吸附性能研究

利用化学修饰法合成酚羟基修饰吸附树脂LM-6,通过批量吸附实验考察LM-6对2-萘酚的吸附热力学及动力学行为。结果表明,在实验条件下,LM-6对2-萘酚的吸附数据符合Freundlich吸附等温方程且为优惠吸附,吸附能力随着温度的升高而增加。吸附自由能变G<0,表明吸附过程是自发的过程;S<0,表明吸附过程中熵增加。吸附平衡时间为10 h,吸附动力学数据符合拟二级动力学方程和颗粒内扩散模型。     

棒材步进式冷床机构设计选型

介绍了棒材步进式冷床机构设计选型方面的经验 ,通过对使用不同机构的冷床主要部件的对比描述 ,介绍了较先进的机构 ,对冷床的发展趋势进行了探索。     

航空钛合金板胶接表面粗糙度的超声测量

采用一种新的超声频谱法快速测量航空钛合金板经喷砂预处理后的胶接表面粗糙度,并引入表面面积均方根粗糙度系数ST来表征材料表面三维微观形貌.以航空Ti-6Al-4V钛合金胶接板为测量试样,超声换能器接收测试试样表面的反射回波,并计算得到AR参数谱.以反射脉冲AR参数谱和声波镜面反射理论为基础,建立了有关脉冲波声反射系数和表面均方根粗糙度系数ST的数学模型.利用表面粗糙度系数理论模型.数值计算反射回波的理论频谱曲线,并与实测反射回波AR谱进行拟合.利用最小值搜索算法,处于最佳拟合时的表面粗糙度系数ST即为试样胶接表面的测量结果.实验表明,超声反射频谱法测量结果与轮廓仪测量结果符合得很好,该测量方法在材料或零部件表面粗糙度在线测量中具有广泛的应用前景.     

作物生长条件下蒸发与蒸腾的模拟及土壤水份动态预报

以由能量平衡原理及边界层水汽扩散理论而导出的Ｐｅｎｍａｎ－Ｍｏｎｔｅｉｔｈ公式为基础，确立了棵间潜在蒸发及潜在植株蒸腾的计算模式．建立了以作物根量分布为基础的根系吸水模型．结合实测资料，导出了棵间实际蒸发的经验模式．应用上述经验与半经验模型，结合非饱和土壤水份运移方程，对田间土壤水份动态进行了模拟与预测，其结果与实测结果拟合较好．