基于散体动力学理论的掘进机星轮装载机构研究

为了解决掘进机星轮对物料推力过大,物料因惯性而不随轮齿同步运动的问题,运用散体动力学理论分析掘进机装载机构的星轮轮齿推移物料的运动过程.建立力学和数学模型,推导出掘进机星轮机构装载过程中保持物料稳定运行的推力计算公式和轮齿许用加速度范围;并用计算机模拟轮齿推力与轮齿参数的关系,提出了轮齿推移物料的动力学模型和方程,为星轮装载机构的设计和研究提供了参考依据.     

The amphibians and reptiles of Nosy Be (NW Madagascar) and nearby islands: a case study of diversity and conservation of an insular fauna

Surveys of the amphibians and reptiles on Nosy Be (an island off north-west Madagascar) and nearby islands were undertaken between 1991 and 2001 and are discussed here in view of biodiversity considerations and conservation efforts. Since Nosy Be is the type locality of several amphibian and reptile taxa, their exact status is of crucial importance for the nomenclatural stability of many groups of the Madagascan herpetofauna. A total of 20 amphibian and 61 reptile species (excluding marine reptiles) was confirmed for this archipelago. Other species (Mantidactylus horridus, Androngo elongatus, Typhlops madagascariensis, T. reuteri, Micropisthodon ochraceus and Pararhadinea melanogaster) were not found during these inventories, but are quoted in the literature or housed in herpetological collections, and are considered as likely to be present at Nosy Be. A further 18 taxa are tentatively excluded from its fauna, due to biogeographic incongruence and/or lack of reliable voucher specimens. Few taxa are so far only known from the island; they may represent endemics or may have been overlooked on the adjacent mainland. They are respectively Stumpffia pygmaea, Mabuya lavarambo, Lygodactylus h. heterurus, Lycodryas granuliceps and Typhlops reuteri. Heterixalus tricolor too is likely to be present on Nosy Be only, but the difference with respect to taxa present on the mainland needs to be confirmed. Several species are known from nearby islands and islets surveyed (11 amphibians and 26 reptiles). A few of them (Heterixalus 'variabilis', Kinixys belliana, Furcifer oustaleti, Mabuya comorensis, Paracontias milloti) are present on some of these islands but have not yet been found on Nosy Be. Much of the field research was conducted at Lokobe, a strict nature reserve still characterized by good forest coverage (typical of the Sambirano Domain), and an important area of biodiversity. With 15 amphibian and 45 reptile species, Lokobe hosts 81% of the overall Nosy Be herpetofauna: of the species found during our surveys, only Heterixalus tricolor, Hoplobatrachus tigerinus, Gehyra mutilata, Phelsuma dubia and Crocodylus niloticus were only found outside the reserve. In view of this, the protection of Lokobe should be assured and reinforced. Except for Lokobe, habitats on Nosy Be are largely anthropogenic, and have a lower species diversity, especially where there is intensive agriculture. At other sites (e.g. ylang-ylang and coffee plantations) and in forested bands along roads, species diversity is still high: careful management of these anthropogenic habitats might also assure the survivorship and conservation of a diverse herpetofauna outside the protected area.     

曾侯乙墓漆箱房星图考

运用出土文物与文献记载、实际天象三者相结合的考证方法,认为曾侯乙墓漆箱侧面所绘天文图象为天驷房星图。房星又称为农祥星,其星神是古代天子或诸侯在农历岁首于郊外举行籍田礼时祭祀的对象,因此绘有房星图的天文图漆箱是曾侯乙举行籍礼时必须携带的重要仪具之一。     

一种新型相控触发电路

本文介绍一种适用于双反星形带平衡电抗器整流电路的触发器，并对其工作原理进行了较为详细的分析。     

基于多元图形特征融合原理的降维方法研究

降维是将高维模式映射到低维子空间的过程.在降维后的低维子空间进行分类往往能得到更好的效果.本文以高维数据为研究对象,采用多元描述图对高维数据进行可视化表达,采用多元图图形特征融合的方法对高维数据进行降维,用K邻分类器进行分类效果评价.与Fisher线性判别及其他一些常用非线性降维方法相比,本文所提方法在数据的可视化以及分类精度等方面均有较好效果.     

G10×Sn的交叉数

本文证明了五阶图G10与星Sn的笛卡尔积交叉数,填补了Marian Klesc所给出的五阶图与星图的笛卡尔积交叉数表格中的又一个空白.     

星图识别的剖分算法

为了提高星敏感器的测量速度和精度,在星图识别中首次采用了在地球物理地质建模中有着广泛应用的剖分算法。利用这一算法进行星图的匹配识别,仿真实验结果表明与现有的星图识别算法相比,此算法具有高的识别率,良好的实时性和鲁棒性,且所需导航星库的容量小,检索速度快。     

发展中的广西民族学院数学与计算机科学系

介绍广西民族学院数学与计算机科学系建系40多年来,特别是改革开放以来的发展情况.     

活动天体的可观察时空效应

本文认为,大质量活动天体的电磁辐射也携带强烈的时空弯曲信息,为此,先将给出表征时空弯曲信息的Riemann曲率辐射功率表示式;次将它置于二维时空情况做具体计算,表明它内边含有丰富的红移因子;最后为了能同观察比较,再将亮度与恒星星等联系起来。