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51.
为了合理确定液体燃料环氧丙烷爆炸抛散比药量及点火延迟时间,进行了相关的实验与数值模拟研究,用CCD像机记录了三种比药量下爆炸抛散过程,并从云雾成长过程中不同时刻的燃料浓度及云雾氧平衡两方面对三种比药量下的点火延迟时间进行了讨论。运用数值方法对2个特定延迟时间点的爆炸场压力进行了计算,给出了压力峰值随距离变化的曲线。 相似文献
52.
抗爆设计中材料极限塑性应变的一种确定方法 总被引:2,自引:0,他引:2
为了确定抗爆设计中材料的最大许用塑性应变值,以单向受拉的矩形薄板为研究对象,假定板宽和厚度方向的变形相等,利用塑性变形的体积不变理论,通过等效应变的思想,提出了一种以延伸率为基本变量的材料合理许用应变值的确定方法·利用ANSYS软件对纯铝圆板在周边全约束、承受均布爆炸模拟载荷作用下的破坏变形进行了有限元数值模拟计算,当计算得到的板内最大等效应变接近本文提出的极限塑性应变值时,计算得到的圆板相应破坏位移与Pilkington实验数据基本一致 相似文献
53.
对原油罐区形成的爆炸性环境进行了分析,应用 IBM—PC/AT 或兼容机对爆炸性气体混合物的爆炸极限进行计算,为在原油罐区爆炸性环境中确定潜在爆炸的危险程度及安全可靠地使用自动化仪器设备,提供足够安全的数据。 相似文献
54.
建立了工程爆破冲抛悬浮物潮对流扩散数值预测二维模型,并利用此模型预测了南海大亚湾马鞭洲原油码头场地平整(爆破填土)工程冲抛悬浮物对周围海域的影响,取得了较满意的结果 相似文献
55.
安伟科 《湖南理工学院学报:自然科学版》2006,19(4):36-39
在超强飞秒激光与氘团簇的相互作用中,分析了可以引发核聚变的高能氘核产生的原因,提出了团簇复合膨胀的机制,计算了氘核动能及团簇解体的时间,为选取合适的激光脉冲宽度参数提供参考。 相似文献
56.
Despite a long history of research on the Early Cambrian in China most available data on small skeletal fossils concern fossil associations of the shallow carbonate platform. Information on skeletal fossils from marginal shelf environments of the Yangtze Platform is scanty, which may reflect the rarity of fossils in deeper sedimentary environments but is also due to limitation of carbonate distribution and outcrops, difficulties in fossil extraction, and a general research focus on the Precambrian-Cambrian boundary beds on the carbonate platform. Here we present a documentation of Meishucunian to Qiongzhusian small skeletal fossils from the lower Hetang Formation and the chert unit at its base from the Jiangshan region, Zhejiang Province, representing a relatively deep shelf environment compared to the inner shelf region. The earliest association (Meishucunian) from the chert unit underlying the Hetang Formation is mainly characterized by the occurrence of Protohertzina anabarica, P. unguliformis, Fengzuella zhejiangensis, and Kaiyangites novilis, which differs somewhat in composition from SSF-associations of typical inner shelf deposits. The enigmatic skeletal fossil Fengzuella zhejiangensis, which exhibits an unusual secretional growth mode previously unrecognized from the Early Cambrian, is described in detail. A younger (Qiongzhusian) fossil association contains numerous arthropod remains, such as disarticulated spines of arthropods (Jiangshanodus- and Kijacus-type), which have previously been considered as conodont-like fossils, and bradoriid valves. 相似文献
57.
单流出B型过程爆发后的期望停留与寿命 总被引:2,自引:2,他引:0
单流出B型Q过程是一类在理论和实际上很重要的Markov过程,它具有很好的性质,它的Martin流出边界Be是单点集{b},文中研究了此类过程爆发后的期望停留与寿命。 相似文献
58.
岩体中爆炸与冲击下的破坏研究 总被引:13,自引:2,他引:11
阐明了揭示岩体中爆炸与冲击真实的变形与破坏过程必须继续研究基于微观物理原理和细观物理力学的理论。建立简单工程实用的介质在爆炸和 冲击作用下的统一的分阶段连贯的不同时空尺寸的动力构模型,必须研究材料爆炸和冲击下的在不同的特征能量尺度及其传输速度下统一的分阶段连贯的动力破坏过程和动力破坏准则。 相似文献
59.
A number of recently evolved animals possess poison glands for feeding and/or defense.However,examples of such animals are rare in the fossil record.We report a fossil arthropod Isoxys curvirostratus from the Early Cambrian Chengjiang biota of China.This species is regarded as the oldest known venomous arthropod based on the presence of venomous glands in its head region.The adult animal is 2-5 cm long and the body is covered entirely with a carapace.The presence of large stalk eyes and a pair of stout grasping appendages with a terminal spine suggest it was raptorial.Interestingly,the two pear-shaped,three-dimensionally preserved objects that are present in the head region and at the base of the grasping appendages closely resemble the venom glands of some living arthropods in size,shape,and position.These features indicate that the presence of venomous predators could date back 520 million years.Furthermore,our observations suggest that the feeding strategies and organs adapted for this purpose had already reached a high level of diversity and anatomical sophistication in the Early Cambrian ecosystems. 相似文献
60.
Bathynotus: A key trilobite taxon for global stratigraphic boundary correlation between Cambrian Series 2 and Cambrian Series 3 总被引:2,自引:0,他引:2
The Cambrian trilobite Bathynotus is a special morphology of Redlichiid,which is characterized by a wider thorax axis and an 11th macropleural segment bearing a long,backwardly directed spine.Additionally,its 12th and 13th pleural segments are narrow and they terminate at a fulcrum where they fuse together and to the posterior edge of the long macropleural spine.The genus is widely distributed,occurring in North America,Siberia,the Altay-Sayan fold belt of Russia,South China,the Tarim Basin of China,and Australia.It occurs primarily in deposits of the upper part of the continental slope,at the transition between stable platform settings and subsiding margins of the late Early Cambrian.Here,we recognize three species of Bathynotus from China,including B.holopygus which is widespread around the world.Although six species of Bathynotus have been reported from Siberia and the Altay-Sayan fold belt area of Russia,data presented here suggest that only three of these species are valid.Bathynotus exhibits a short geological range,with its first occurrence late in the unnamed Cambrian Series 2 and the last appearance datum of Bathynotus at the boundary of Cambrian Series 2 and Cambrian Series 3.The late appearance datum (LAD) of Bathynotus provides an important global stratigraphic marker of the boundary between Cambrian Series 2 and Cambrian Series 3. 相似文献