金属材料弹性模量随机场相关特性的实验与分析

利用弹性模量和硬度的联系,完成了铝合金LY12CZ-M和合金钢30Cr Mn Si A弹性模量随机场相关特性的实验测量及分析。具体工作包括测量试件空间各点的洛氏硬度,并以区域化变量理论中的相关函数为工具对测量数据进行统计分析。分析结果表明:金属材料弹性模量随机场的变异系数在7%左右;随机场的空间连续性较好,不存在块金效应;相关函数模型宜选用单指数型;随机场不同方向上的相关特性几乎相同。     

A new genus and two new species of Pudeoniscidae Lemos de Castro 1973 (Crustacea: Isopoda: Oniscidea) from Brazil

To date, the family Pudeoniscidae includes six species and three genera, Pudeoniscus, Brasiloniscus and Iansaoniscus, with distributions restricted to Brazil. Here, we redefine the family Pudeoniscidae based on the discovery of a new genus and two new species, Oxossioniscus pataxo sp. nov. and Oxossioniscus akoko sp. nov., from the Brazilian Atlantic forest in the state of Bahia, and on the examination of Pudeoniscus birabeni and Pudeoniscus obscurus. Moreover, P. obscurus is re-described and new records are provided for P. birabeni.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:A0123730-C623-49CE-8665-AE17FDDF994A.     

Historical review and redescription of three poorly known species of the catfish genus Trichomycterus from south-eastern Brazil (Siluriformes: Trichomycteridae)

ABSTRACT

This study is primarily directed to the most poorly known species of the genus Trichomycterus, comprising five nominal species (T. florensis, T. immaculatus, T. nigricans, T. paquequerensis and T. santaeritae) endemic to south-eastern Brazil. One of them, T. nigricans, is the type species of the genus, involved in taxonomic problems for over 150 years. A detailed historical review, accompanied by examination of type specimens and recent collections, revealed that the correct type locality of T. nigricans is in the vicinity of Rio de Janeiro, not Santa Catarina as commonly appears in the literature; specimens previously misidentified as T. nigricans from Santa Catarina belong to a possibly undescribed species of the genus Cambeva; T. paquequerensis is a synonym of T. immaculatus, and T. florensis is a synonym of T. santaeritae; and the hypothesis that T. santaeritae is closely related to the Amazon Sarcoglanidinae is refuted. The three valid species are redescribed. These species are members of a clade also including T. caipora that is highly supported by molecular data, diagnosed by a pronounced posterior maxillary process and caudal fin emarginate at least in larger specimens. A subclade comprising T. caipora, T. nigricans and T. santaeritae is diagnosed by a long maxilla and a bifid anterior extremity of hypobranchial 3.     

随机产出下的农产品供应链合同

本文设计了存在外部市场的二级农产品供应链,对农产品销货补货渠道进行分析,提出一种考虑外部市场的成本-收入共享合同。研究结果表明,供应商通过与加工企业共享丰收年超出订单量的额外收入,能有效激励加工企业增加订单量,提高双方利润;增添加工企业从外部市场进行补货的渠道能有效缓解供应商欠收的经济压力;考虑外部市场的成本-收入共享合同,能推迟供应链成员退出市场的时间点,利于提高供应链稳定性。     

含有状态时滞的受扰线性离散系统前馈-反馈最优控制

对在随机噪声环境下含状态时滞的线性离散系统的最优控制问题进行了研究。利用卡尔曼滤波算法求得随机干扰的最优估计值,并构造一个敏感度函数,根据麦克劳林展开式将原系统的求取过程转化为通过构造一个两点边值问题族来求解。同时在最优控制律中构造一个补偿函数以减小运算中所带来的误差。将原系统的最优控制律近似估算成M阶前馈-反馈次优控制律,再由分离原理得到含有状态时滞的受扰线性离散系统前馈-反馈最优控制律,最后通过给定一个M的具体值得到M阶的前馈-反馈次优控制律的仿真图像来对比前馈-反馈与经典状态反馈的控制作用,表明前馈-反馈在最优控制律中具有更好的控制效果。     

基于一种改进RRT算法的足球机器人路径规划

针对足球机器人运用传统快速扩展随机树(RRT)算法进行路径规划时随机性大的问题,提出了一种目标引力式的RRT路径规划算法。该算法在RRT算法的基础上引入了一个目标引力函数,避免了扩展随机树向目标点以外的方向生长,改进了快速扩展随机树缺乏确定性的问题,提高了足球机器人在路径规划方面的效率。仿真实验结果表明,该算法能够得到最佳路径,同时可以有效提高路径的规划速度。     

关帝山国有林管理局种苗业发展思路初探

通过分析关帝山国有林管理局种苗发展的现状、存在的问题,并结合当前形势提出了关帝山国有林管理局种苗发展思路。     

关于提高《随机数学》教学效果的教学策略分析

教学策略是以教育思想为指导,在特定的教育情境中,为实现教学目的而制定,并在实施过程中不断调整、优化,以使教学效果趋于最佳的方案。本文针对理工科《随机数学》教学过程中的教学策略进行了分析和探讨,指出教学策略应该伴随整个教学过程的始终,重点做好课前、课上以及课后三方面的教学工作,使学生真正理解和掌握《随机数学》学科所研究的对象、思想方法及实践意义。     

The first Leptanilloides species (Hymenoptera: Formicidae: Leptanilloidinae) from eastern South America

We describe a species of the exclusively Neotropical dorylomorph ant genus Leptanilloides (Leptanilloidinae), Leptanilloides atlantica sp. nov., based on workers collected in the Atlantic Forest, São Paulo, south-eastern Brazil. The 11 species of Leptanilloides described are known from relatively high altitudes in western America (from the Andes foothills in Bolivia to Sierra Morena in Mexico). The discovery of a Leptanilloides species in south-eastern Brazil represents a significant range extension for the genus; this new species shares characters with Leptanilloides biconstricta (Bolivia), Leptanilloides femoralis (Venezuela) and Leptanilloides gracilis (Mexico) and may be distinguished based on a combination of traits. The hypogaeic habits of Leptanilloidinae combined with inefficient collecting techniques may explain the paucity of information and of specimens of this group in most museum collections as well as its present apparent disjunct distribution. We compare Leptanilloides distribution to that of other organisms that show similar disjunct patterns in the Andes and montane sites in the Brazilian Atlantic Forest. http://www.zoobank.org/urn:lsid:zoobank.org:pub:E7E334AA-58C0-455D-A0A6-724D29226DD0