Study on the Sliding Displacement of a Sliding Structure Subjected to Multi-directional Earthquake Excitation

The investigation of sliding isolation is mainlyfocused on the response of a structure subjected to asingle directional earthquake excitation. Fan andTang (2001) studied the slide limited friction (S LF)base isolation system, using a sequential exponentialfriction model. Zhang and Cheng (2001) studied theisolated effect of a sliding bearing as a friction damp er. Xiong and Yu (2002) studied the numerical meth od of sliding isolation system. But studying a singlecomponent of e…     

Contribution of subducted Pacific slab to Late Cretaceous mafic magmatism in Qingdao region, China: A petrological record

Abstract The occurrence of the Pishikou mafic dike in the Qingdao region, China provides important constraints on the origin of Late Cretaceous (86–78 Ma) mafic magmatism on the eastern North China craton. The Pishikou mafic dike is distributed in the Cretaceous Laoshan granitoid body, Qingdao region and contains peridotitic and granulitic xenoliths, xenocrysts, and megacrysts. Rocks from the Pishikou mafic dike are basanites and have low SiO₂ (< 42 wt%) and Al₂O₃ (12.5 wt%) contents, and high MgO (> 8 wt%), total alkalis (Na₂O + K₂O > 4.8 wt%, Na₂O/K₂O > 1), TiO₂ (> 2.5 wt%), CaO (> 9 wt%) and P₂O₅ (> 1 wt%). In trace element abundances, they are highly enriched in large ion lithophile elements (LILEs) and light rare‐earth elements (LREEs) (ΣREE = 339–403 ppm, (La/Yb)_N = 39–42) without high field strength element (HFSE) depletion. These rocks have radiogenic Sr and Pb, and less radiogenic Nd isotopic compositions [(⁸⁷Sr/⁸⁶Sr)_i > 0.7059, εNd ≈ 2.7–3.8 (²⁰⁶Pb/²⁰⁴Pb)_i ≈ 18.0 ± 0.1]. The diagnostic elemental ratios, such as Nb/La, Nb/U, and Nb/Th, are compatible with those of mid‐oceanic ridge basalts (MORBs) and oceanic island basalts (OIBs). Therefore, the Pishikou mafic dike has a geochemical feature completely different from those of the Early Cretaceous mafic dikes from the Qingdao region, but similar to those of back‐arc basalts from the Japan Sea. This geochemical feature suggests that the Pishikou mafic dike was derived from an asthenosphere source, but contaminated by materials from the subducted Pacific slab. The discovery of this mafic dike thus provides a petrological evidence for the contribution of subducted Pacific slab to the Late Cretaceous magmatism in the Qingdao region of the eastern North China craton.     

日地关系研究的一种新观点介绍

介绍了Ｇ．Ｐ．Ｇｒｅｇｏｒｉ提出的关于日地关系的新因果链：太阳→太阳风（及月球引潮力）→地幔内地磁感应々→“发电机”感应电流→焦耳热→火山（及地热流）→水或其它微量元素进入大气圈→控制长期气候变化。对这种因果链提出的背景知识、资料证明及应用前景作了详细说明。介绍了国内一些学者关于日地关系的看法，并将二者加以比较。提出了对日地关系研究的看法及急需解决的问题。     

Sedimentary charateristics and hydrocarbon accumulation in Northeast Sichuan basin

Northeast Sichuan basin is a Mesozoic-Cenozoic basin in the northern margin of the Yangtze plate which has a complex tectonic background and hydrocarbon accumulation history. By means of the analysis method of wave processes, major cycles of sedimentary wave process in this basin have been studied. The results show that there are five-order cycles corresponding to 760, 220, 100, 35 and 20 Ma respectively, two first-order sedimentary cycles (220 Ma) and four secondorder sedimentary cycles (100 Ma). The authors find that the second-order sedimentary cycles are well matched with reservoir formation cycles through studying the relationship between second-order sedimentary cycles and reservoir formation cycles, and divide three reservoir formation cycles in this basin. __________ Translated from Journal of Jilin University (Earth Science Edition), 2007, 37(3): 513–518 [译自: 吉林大学学报(地球科学版)]     

冲绳海槽沉积物干酪根特征

本文采用元素分析、镜下观察、红外光谱、扫描电镜和热解分析等技术,分析了冲绳海槽柱状样中腐植酸、富里酸和干酪根的化学、物理特征,并探讨了它们之间的成因关系和干酪根类型。沉积物的产烃能力甚差,每吨沉积物仅能生成0.49～1.18kg烃类物质。     

基于气象预警信息的大连气象微博评论情感分析及发布策略建议

微博在气象预警信息传播及气象部门收集社会公众信息反馈中发挥了积极作用,并产生了海量级的交互信息,客观分析此类信息对于气象部门及时引领舆论导向和调整发布策略具有较高的参考价值。文中基于2017年1月1日—2020年7月3日大连市重大气象灾害过程,运用自然语言处理、情感分析等方法对大连气象微博中与气象预警相关的评论内容进行情感分析研究。结果表明：公众关注最多的是天气预报准确率、天气过程对于生活影响以及信息发布的及时性。公众对重大天气过程特别是致灾天气过程本身负面评价多于正面,发布策略应根据气象灾害持续时间及时调整预警信息内容和发布频次;公众对大风、冰雹等气象灾害预警信号关注度随季节变化明显,发布策略应针对旅游业、养殖户、种植户等提出专业防范对策;针对发布频率高的大风预警信号,有必要调整业务发布规范,同时关注灾后事件信息的跟踪发布;研究发现,负面情感主要针对天气预报的准确度。     

64层锥束CT扫描的优化系统

近年来X射线断层成像(CT)技术获得了突飞猛进的发展,自1998年推出4层螺旋CT后,CT扫描设备在容积覆盖,空间分辨率,扫描速度,切片数方面取得了长足进展.这不仅给医学应用带来了深远的影响,同时也给CT系统设计提出了巨大的挑战.容积CT(VCT)的设计过程引入了各种策略来战胜其复杂性.这些方法学包括:理论分析,系统性能预测的图像分析工具,各种基于专家背对背评价的参数优化.本文论述了64层CT系统设计中的一些考虑因素及优化过程.这些设计过程保证了锥束CT的优化性能.首批客户的应用反馈显示了我们设计实践的有效率性.     

沪昆客专克地坝陵河特大桥工程地质问题及对策研究

克地坝陵河双线特大桥为沪昆客专贵州段内重点控制工程之一。桥梁工程穿越区内地形、地质条件异常复杂,受地形切割地层及地质构造等多种因素综合控制,区内危岩落石、滑坡、岩堆、岩溶等工程地质问题频发。利用测绘、物探、钻探等资料,对桥址区内主要工程地质的类型、规模、危害性以及防治对策等方面进行深入分析、研究。研究成果不仅能为铁路选线提供依据,而且对围岩落石问题的处理及桥梁工程设计、施工以及运营都具有重大意义。     

离散Hopfield神经网络的稳定性

研究离散Ｈｏｐｆｉｅｌｄ神经网络的串行稳定性和并行稳定性，分别提出了条件较弱的串行稳定性和并行稳定性的新判据．     

交流电弧直读发射光谱法测定地球化学样品中银、硼、锡、钼、铅的方法研究

本文建立了交流电弧直读原子发射光谱法测定地球化学样品中银、硼、锡、钼、铅的分析方法。以K2S2O7、NaF、Al2O3、碳粉为缓冲剂,Ge为内标,优选了分析线对,曝光时间为25s,同时扣除分析线和内标线背景。选取国家一级地球化学标准物质（GBW07103、GBW07104、GBW07107、GBW07312、GBW07302a、GBW07304a、GBW07305a、GBW07307a、GBW07406、GBW07446、GBW07454、GBW07456）作为标准系列,以对数坐标二次曲线拟合标准曲线,并采取两次平行分析取平均值的计算方法。方法检出限为:Ag:0011×10-6、B:054×10-6、Sn:019×10-6、Mo:0034×10-6、Pb:066×10-6,精密度为:Ag:401%～833%、B:377%～786%、Sn:294%～817%、Mo:303%～1094%、Pb:201%～1111%。经岩石、水系沉积物、土壤国家一级标准物质验证,测定值与认定值符合。本方法操作简便、工作效率高,是一种新的测定地球化学样品中银、硼、锡、钼、铅的分析方法,可推广应用于大批量地球化学样品的分析测试。