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81.
马文强 《信阳师范学院学报(自然科学版)》2019,(3):498-504
为分析遗留下分层开采时再生顶板的运动规律及矿压显现特征,以北皂煤矿油页岩分层下行开采为背景,结合前期研究中建立的下分层再生顶板碎裂结构模型及其分带特征,通过改进传统的相似材料配比构建了下分层再生顶板碎裂结构相似材料试验模型,并对下分层开采中的顶板运动、支承压力分布及支架受力特点进行了研究.结果表明:受二次采动影响,再生顶板垮落岩块碎胀系数较小,压实程度较好.上、下分层采高接近情况下,下分层工作面支承压力影响范围及峰值均小于上分层,分别为上分层的38%和51%;下分层支架受力为上分层的91.6%;下分层采出后顶板中不规则冒落带及规则冒落带高度均增加至采前的3倍;裂隙带高度增加为采前的1.6倍.为类似条件的下分层采场设计、支架选型提供依据. 相似文献
82.
《Journal of Natural History》2012,46(6):1413-1419
Didogobius schlieweni sp. nov. is described from a single specimen collected among pebbles in shallow water at Unije island, near Cres, in the northern Adriatic Sea. The holotype has vivid dark and pale patterning, and is assigned to Didogobius on the basis of head neuromast patterns and meristic features. Diagnostic values of the latter are D2 I/12, A I/11, P 17, and LL 55–56. A key to species of the Chromogobius and Didogobius complex is provided. 相似文献
83.
84.
The South Korean species of the genus Exochus are revised. Ten new species, Exochus acostulatus Lee & Choi, sp. nov., Exochus adentatus Lee & Choi, sp. nov., Exochus areolaris Lee & Choi, sp. nov., Exochus carinalis Lee & Choi, sp. nov., Exochus dentisternum Lee & Choi, sp. nov., Exochus depressus Lee & Choi, sp. nov., Exochus nigritulus Lee & Choi sp. nov., Exochus occipitalis Lee & Choi, sp. nov., Exochus orbitalis Lee & Choi, sp. nov. and Exochus propodealis Lee & Choi, sp. nov., are described. Also, 21 species of this genus are reviewed and newly recorded from South Korea, with diagnoses provided. A key to the South Korean species of Exochus and illustrations of external characters are provided.
http://zoobank.org/urn:lsid:zoobank.org:pub:B28700A7-9CA7-4AE7-9816-9C8F4CD46160 相似文献
85.
《Journal of Natural History》2012,46(6):1325-1331
A new genus of Conchaspididae, Asceloconchaspis gen. nov., is described for Asceloconchaspis milleri sp. nov., a new species from Florida, USA. Unlike other conchaspidids, the adult female and second instar of the genus lack legs. The presence of legs is one of the important, distinguishing characters at present separating the Conchaspididae from the Diaspididae. However, the new genus also possesses well-developed antennae and has multilocular disc pores on the abdomen in the adult female; these distinctly conchaspidid characters are never found in the Diaspididae. Asceloconchaspis is closely related to Fagisuga Lindinger, a monotypic genus with primitive characters described from South America on Nothofagus. A key to the four known genera of Conchaspididae is provided, and the morphology and distribution of the Conchaspididae are discussed. 相似文献
86.
《Journal of Natural History》2012,46(5):953-959
The order Misophrioida is recorded for the first time in Brazilian waters and the new species Archimisophria squamosa, with some important plesiomorphic features, is described. 相似文献
87.
Bristly millipedes (subclass Penicillata, order Polyxenida) are minute diplopods characterised by uncalcified cuticle and a body covered with unique tufts of bristles. The order is found worldwide and comprises less than 200 described species divided into three families, with many of the species and genera being poorly known. The first evolutionary analysis of the order presented here utilises both molecular (COI, 18S rRNA and 16S rRNA) and morphological data to examine monophyly of the families and subfamilies and the evolutionary relationships between them. Maximum likelihood analysis was based on molecular data only, whereas parsimony analyses were based on molecular data as well as combined morphological and molecular data. The results of these analyses with two different optimality criteria were incongruent in many aspects. Unlike parsimony, the likelihood result found strong support for a basal position of the family Synxenidae and separation of the order into two monophyletic clades corresponding to the two superfamilies Synxenoidea, containing the family Synxenidae, and Polyxenoidea, containing the families Polyxenidae and Lophoproctidae. Parsimony results did not support the existence of the two superfamilies. Both analyses resolved the family Synxenidae as monophyletic and Polyxenidae as polyphyletic, whereas the family Lophoproctidae was shown to be paraphyletic in likelihood and monophyletic in parsimony analysis. The subfamilies Monographinae and Polyxeninae were found to be monophyletic in the likelihood tree but parsimony suggested paraphyly of both. The results suggest that further revision of the systematics of the Polyxenida may be necessary. However, a much larger molecular data set will be necessary to clarify and provide stronger nodal support for phylogenetic trees and to confirm the relationships, particularly of the families Polyxenidae and Lophoproctidae. Molecular identification is likely to be an important tool for this taxonomically challenging order in future. A simplified key to the genera is provided. 相似文献
88.
为探究航班运行风险的产生、传播与控制过程, 首先统计华北区域航班运行数据共计76个风险节点。然后,采用偏秩相关系数构建风险网络, 再使用社团模块探测算法与三角最大滤波法验证网络适用性。并且, 提出一种适用于航班运行风险分析的SEIR(susceptible-infected-exposed-recovered)模型。根据动力学传播结果, 聚类定位网络传播中关键节点。最后, 采用前置预防与战术处置两类控制方案。计算结果表明,仅控制5个节点后, 感染峰值可降低18.44%, 峰值时间推后两个周期, 起降等重要操纵节点被感染次数平均下降11.74%。该方案在感染峰值、感染周期、重要节点感染3个方面的抑制效果均占优。以上结果证实, 所提方案可有效用于航班运行风险问题分析。 相似文献
89.
中国绿色建筑市场正处于稳步发展阶段,但仍然存在供需结构不合理、各方利益关系协调不均衡等问题。基于供给侧结构性改革视角,分析了绿色建筑发展过程中“供应侧”和“需求侧”两端正外部经济性特征,构建了政府与供、需两端关键主体动态博弈模型,提出了基于政府、房地产开发商和消费者的对策建议。通过研究,表明绿色建筑发展前期阶段存在正外部经济效应和市场失灵共生现象,供、需两端并不能满足帕累托效率的平衡量要求,只通过市场自身资源配置功能调节绿色建筑市场结构和各主体利益关系存在局限性,政府的适度干预有利于实现供、需两端最优利益组合和利益均衡,有助于加快实现传统建筑市场转型升级。 相似文献
90.
《Journal of Natural History》2012,46(4):855-861
A new genus, Protogamasellopsis (family Ascidae), is proposed to accommodate the type species Protogamasellopsis corticalis sp. nov and Protogamasellus diocorus Manson. The classification of the Protogamasellus complex is discussed and a new subgenus, Protogamasellodes (type: Protogamasellus hibernicus Evans), is erected. A key is given for the separation of the genera Gamasellodes, Protogamasellus s.lat and Protogamasellopsis. 相似文献