循环应力对储气库岩石微观结构及力学性质影响数值模拟

针对储气库循环注采过程中循环应力对储气库岩石产生疲劳损伤的问题。利用颗粒离散元法建立岩心真三轴数值模型,根据岩心室内试验标定数值模型参数,然后对数值模型进行多周期等幅值轴向循环应力加载,研究循环应力对储气库岩石微观结构及力学性质的影响。结果表明:循环应力加载过程中,模型内生成的无黏结接触数量和微裂缝数量逐渐增多,而生成位置受原始裂缝控制明显,模型孔隙度逐渐减小,且模型内无黏结接触数量、微裂缝数量和孔隙度的变化速率均呈递减趋势;相同应力水平下模型侧向应变和轴向应变均增大,但侧向应变占主导地位;模型弹性模量逐渐降低,而模型泊松比和损伤量逐渐增加,且模型弹性模量、泊松比和损伤量的变化速率均呈递减趋势。     

晚清小说《泪珠缘》之“仿红”管窥

《泪珠缘》是晚清典型的“仿红小说”，叙事艺术上采用家族———社会立体网络式结构，在故事情节上运用线式情节结构，在人物形象上也借鉴了《红楼梦》，并融合了晚清特有的时代特色，是一部优秀的家庭小说。     

Underdetermined DOA estimation and blind separation of non-disjoint sources in time-frequency domain based on sparse representation method

This paper deals with the blind separation of nonstation-ary sources and direction-of-arrival （DOA） estimation in the under-determined case, when there are more sources than sensors. We assume the sources to be time-frequency （TF） disjoint to a certain extent. In particular, the number of sources presented at any TF neighborhood is strictly less than that of sensors. We can identify the real number of active sources and achieve separation in any TF neighborhood by the sparse representation method. Compared with the subspace-based algorithm under the same sparseness assumption, which suffers from the extra noise effect since it can-not estimate the true number of active sources, the proposed algorithm can estimate the number of active sources and their cor-responding TF values in any TF neighborhood simultaneously. An-other contribution of this paper is a new estimation procedure for the DOA of sources in the underdetermined case, which combines the TF sparseness of sources and the clustering technique. Sim-ulation results demonstrate the validity and high performance of the proposed algorithm in both blind source separation （BSS） and DOA estimation.     

微信电子商务应用价值分析

移动商务发展到现在,在应用层面上最广泛的就是专属APP和基于微信平台上开发的商务应用.微信平台以其应用广泛,粘合度高已成为众多商家特别是第三产业企业应用的首选.从微信商业发展入手,系统讨论微信商业价值形式,能为商业开发应用研究给出一些较为完整的理念,促进移动电子商务应用发展.     

基于贝叶斯网络的复杂装备维修质量评价模型

针对当前装备维修质量评价忽视维修过程影响因素这一问题,将过程评价指标体系作为修后评价指标体系的先验知识,构建了一种基于贝叶斯网络的复杂装备维修质量评价模型。首先,建立了过程评价指标体系和修后评价指标体系,并对各项指标进行了简要分析。然后,建立了维修质量评价的贝叶斯网络模型,通过改进的模糊综合评价方法确定了根节点的先验概率,通过专家经验法确定了子节点的条件概率,并给出了模型的具体求解步骤。最后,通过算例仿真与分析对提出的方法进行了验证。结果表明,提出的方法能够在一定程度上解决复杂装备的维修质量评价问题,为完善复杂装备的维修质量评价理论提供了借鉴。     

不同测试环境对车内空气质量水平的影响研究

通过在蒸发密闭舱、环境模拟舱和真实环境中的静置试验,以及在高速公路和市区路段实际道路上进行的动态试验,定量研究了在不同测试环境下环境本底浓度、环境温度和车辆通风模式等因素对车内空气质量水平的影响。     

硼对第二代镍基单晶高温合金显微组织的影响

硼(B)是强化镍基单晶合金小角度晶界的重要微量元素,但目前关于B对镍基单晶合金显微组织影响的系统报道非常有限。通过对3种不同B含量(质量分数分别为0、0.01%、0.02%)的第二代镍基单晶合金DD11铸态及热处理态组织定量表征,研究了B对相转变温度、(γ+γ′)共晶组织、硼化物的影响。结果表明:B显著降低合金的固液相线,提高铸态共晶组织体积分数;0.01%B的加入,合金中未出现M3B2型硼化物相;而0.02%B的加入,显著促进了骨架状硼化物的形成,降低合金初熔点,引起残余共晶含量的大幅度提高;骨架状硼化物吸收较多的Cr、Mo和W等元素,降低合金的固溶强化效果,可导致单晶合金基体的蠕变性能大幅度降低。研究结果对认识单晶合金中微量元素B的作用机理及优化B成分范围具有理论指导意义。     

An important functional group,benzo[1,3]dioxole,of alkaloids induces the formation of the human telomeric DNA G-quadruplex

Over the past few decades, numerous molecules have been discovered or designed to interact efficiently and selectively with a peculiar DNA structure named G-quadruplex. Some of these molecules have been developed as anticancer agents. To aid the design of anticancer agents, the ability of alkaloids possessing Protoberberine and Benzophenanthridine groups to induce the formation of G-quadruplexes were studied using CD spectroscopy. By careful examination of their structures, we found that a benzo[1,3]dioxole group plays an important role in influencing their inductive properties. The more functional groups the alkaloids have, the stronger their G-quadruplex inductive ability.     

Investigation of silicon on insulator fabricated by two-step O+ implantation

In this paper, we investigated the dose window of forming a continuous buried oxide (BOX) layer by single implantation at the implantation energy of 200 keV. Then, an improved two-step implantation process with second implantation dose of 3×10¹⁵ cm^?2 was developed to fabricate high quality separation by implanted oxygen (SIMOX) silicon on insulator (SOI) wafers. Compared with traditional single implantation, the implantation dose is reduced by 18.2%. In addition, the thickness and uniformity of the BOX layers were evaluated by spectroscopic ellipsometry. Defect-free top Si as well as atomic-scale sharp top Si/buried oxide interfaces were observed by transmission electron microscopy, indicating a high crystal quality and a perfect structure of the SOI fabricated by two step implantation. The top Si/BOX interface morphology of the SOI wafers fabricated by single or two-step implantation was also investigated by atomic force microscopy.     

订货与发货整合批量调度问题

在对文题进行数学描述的基础上，建立求解该类问题的混合整数线性规划模型.证明问题NP 困难性并研究多项式可解子问题，进一步提出了3个启发式算法以及精确求解的分支定界算法.数值实验表明，所提出启发式算法以及分支定界算法的有效性与高效性.