科创中国

工业用线钳表面抛光机床是一种新型的磨削装置,其磨削过程用液压系统控制,从而实现大批量加工.该文首先利用三维设计软件UG NX3进行液压系统结构设计,再从结构方案的确定、主要部件的设计计算以及系统原理图的确定等几个方面对工业用线钳表面抛光机床液压系统进行了详细的分析,确保其性能良好.实验和应用证明:该液压系统运转平稳,稳定性和调节性能较好且密封可靠,使用效果良好.

Life-history theory predicts that in hibemators age of maturation is related positively to body size and negatively to the duration of active season aboveground. Yellow souslik is a large-sized ground squirrel with long hibernation, which suggests late maturation. We used four-year field observations of marked individuals to determine the age of maturation in males through analysis of age-dependent variation in body size, mass, androgen status, timing of spring emergence, ranging patterns and social behavior during the mating season. Yearling males were smaller, lighter, had lower level of fecal testosterone, emerged later and had smaller home ranges than older males. Social activity and the number of females encountered did not differ between age classes. After the second hibernation none of the studied parameters varied with age. Cluster analysis revealed two behavioral tactics: "active" males (adults only) emerged earlier, ranged more widely, initiated more contacts, encountered more females and were heavier than "passive" males (both yearling and adult). Thus, males of S. fulvus reached adult size and matured after two hibernations, which is relatively fast for such a big species with short active period. Indirect evidence for copulations and high variation among yearlings in all parameters suggest that some of them might successfully compete with adults. Active tactic of wandering and searching for females is energetically costly, and probably only adult males in good physical condition can afford it, whereas passive tactic of residing is energy saving and good for adults in poor condition and for yearlings that are continuing to grow.

日本某公司从1960年开始潜心研究PA透明树脂,相继成功研发高透明、低吸水性、尺寸稳定性的TR55和TR90树脂并推向市场.

Models of optimal escape strategy predict that animals should move away when the costs of fleeing (metabolic and opportunity costs) are outweighed by the costs of remaining. These theoretical models predict that more vulnerable individuals should be more reactive, moving away when an approaching threat is further away. We tested whether escape behaviour (includ- ing 'escape calling') ofLithobates sphenocephalus approached by a human was influenced by body size or the initial microhabi- tat that the individual was found in. Irrespective of their size, frogs in the open tended to remain immobile, enhancing their cryp- sis. Frogs in cover showed different responses according to their body size, but, contrary to our initial predictions, larger frogs showed greater responsiveness (longer flight initiation distance and distances fled) than small frogs. Small frogs tended to remain closer to water and escaped into water, while larger individuals were more likely to jump to terrestrial cover and call during escape. Density of frogs near the focal animal had no effect on escape behaviour. This study indicates a range of escape responses in this species and points to the importance of divergent escape choices for organisms which live on the edge of different environments .

为了充分利用GPU集群(Cluster)中各节点的资源,提高GPU集群(Cluster)整体的计算效率.本文以3G网络中海量视频质量分析为研究背景,提出了一种面向CPU和GPU集群的负载均衡策略,构建了一个GPU异构集群系统.实验表明,该负载均衡策略能很好地利用GPU和CPU计算资源、提高集群计算效率.

2014年8月27日,中国计算机之母、著名计算机专家和教育家夏培肃院士在北京中日友好医院辞世,享年91岁.作为中国计算机事业奠基人之一,夏培肃始终坚持中国要做自己的计算机.54年前,她主持研制的中国第一台通用电子数字计算机107机,在1960年是一个传奇.

针对目前飞行器航迹规划中弹道计算量大、耗时长的问题,结合GPU大规模并行计算特性,提出了一种基于GPU的弹道快速计算方法.该方法以4阶Runge-Kutta (R-K)法为基础求解弹道微分方程组,通过计算资源的分配、数据流分段将弹道计算任务映射到GPU线程模型,利用CPU加GPU异构模型的数据流控制能力,实现上千条弹道的并行计算;实验表明该方法计算精度满足要求,并获得几十倍理想加速效果;也为航迹规划系统其他大规模并行计算提供了新的解决思路.

根据超声波在混凝土介质中传播的声速、首波幅值、波形,分析了大尺寸混凝土试样的内部缺陷和均匀性,并对其弹性模量、衰减系数、松弛时间等动态参数进行求解.为了与超声波检测结果对比,采用改进的Hopkinson压杆技术对同配比的圆柱形混凝土试样进行实验研究来测定其相应动态参数,并对比分析了两种方法的不同之处.实验结果表明:两种方法测定的动态弹性模量基本一致;HPB试验测得的衰减系数比超声波试验测得的值大,这说明HPB试验中存在动态损伤的影响;HPB试验测得的松弛时间比超声波测得的增加了近一倍,这表明了在高应变率下,混凝土试样的脆性得到了明显的增加.试验数据可以为工程应用提供借鉴.

平行应急管理方法已经成为一种应对非常规突发事件的有效手段,而计算实验是支持平行应急管理的核心能力,目前还没有针对应急管理的人工社会计算实验管理与控制平台.平行应急管理中人工社会计算实验具有计算实验的基本特性,同时支持平行应急管理的实验设计,需要根据应用需求设计管理控制工具.介绍了计算实验管理与控制的支撑工具;分析计算实验管理与控制对象,设计计算实验的一般过程,分析过程中个对象的交互协作;设计了计算实验管理体系.

为降低异构计算环境下分布式网络模拟的计算开销,提出了一种网络路由模拟任务的非线性划分方法,该方法首先通过标准实验确定异构计算环境中各.计算节点的计算能力,并通过曲线拟合确定各计算节点的路由模拟任务计算开销函数,然后基于各计算节点的计算能力以及计算开销函数,进行路由模拟任务分配及路由拓扑划分,实现对路由模拟任务的非线性划分.基于PDNS的实验表明,该方法相对于传统的均匀划分最多降低路由模拟运行时间50%以上,相对于线性划分最多降低25%以上.并随着路由模拟拓扑规模的增加,该方法的计算时间开销减少量呈现显著递增趋势.