某铁矿充填法采矿引起的地表变形的Flac分析

地下采矿必然会引起采空区围岩的崩塌,围岩向采空区的移动可能涉及到地表,造成地表的陷落．采用充填法,留矿柱法等措施能够减轻地表的沉降．本文借助Ansys进行网格划分后,将其导入Flac数值计算软件中．Flac软件能模拟开采、回填、再向下开挖、再回填等过程,与实际开采和充填一致．对金山店铁矿东区分别进行不充填、20％充填、50％充填的地下开采进行模拟,研究采矿引起的地表沉降问题．分析得出下盘稳定性好于上盘,水平位移和垂直位移在量级上相当,充填越多越能减轻地表沉降．     

物质进化论

世界是物质的。由少数到多数,由简单到复杂,由低级到高级,物质不断地向前进化。物质进化分为阶段进化和层次进化。阶段进化经历了非生物阶段、生物阶段和人类阶段。层次进化经历了个体层次、群体层次和积体层次。当今世界,不仅非生物群体和生物群体积合成物物积体,而且非生物群体、生物群体和人类群体积合成物人积体,成为复合积体。进化的动因是组分作用和组分适应。进化的动力是组分矛盾。人类阶段物质进化的方向是共产主义物人积体。     

双层Y形分叉仿生微通道换热性能及优化设计

针对电子器件的小型化和集成化的趋势以及较高的散热要求,基于仿生思想,设计了双层Y形分叉仿生微通道并研究其传热性能。对于分叉角和分级数进行了优化,得到最佳分叉角为60°,分级数为2。设计双层逆流微通道热沉对电子芯片进行冷却;并构建三维层流流场的计算模型,采用有限体积方法进行数值模拟。结果表明:在相同换热面积下,入口速度为1 m/s时,Y形通道较之平直通道压降减少了37.67%,加热面平均温度降低了7.66℃,同时最大温差降低了6.51℃,温度更加均匀,能很好地提升电子器件的使用寿命和散热性能。相对于单层通道,双层逆流Y形微通道热沉具有更小的压降、更均匀的温度,最高温度下降了3.1℃。双层Y形仿生微通道的设计不仅提高了散热容量,而且有效降低了泵功消耗,可以为电子器件的散热设计提供参考。     

Luminescent Cu doped CdTe nanocrystals via cation exchange of Cu7Te5 nanocubes: From undoped to doped emission

In II-VI group, the doping in CdTe nanocrystals (NCs) is more difficult than other chalcogenides. In this communication, CdTe nanocrystals containing Cu impurities were carefully synthesized based on controlled reverse cation exchange process between as-prepared Cu₇Te₅ nanocubes and Cd²⁺ ions. By well-defined Cu₇Te₅ nanocubes, the obtained CdTe NCs kept the original morphology. The concentration of Cu impurities in CdTe NCs was controlled by the regulation such reverse cation exchange. Additionally, the regulation from band gap (BG) photoluminescence (PL) to the coexistence of the bandgap emission, dopant emission, and surface-state emission was realized. This tailoring from undoped to doped emission in the case of Cu impurities is helpful to study the Cu related doping in telluride NCs.     

Mechanical properties and constitutive behaviors of as-cast 7050 aluminum alloy from room temperature to above the solidus temperature

The mechanical properties and constitutive behaviors of as-cast AA7050 in both the solid and semi-solid states were determined using the on-cooling and in situ solidification approaches, respectively. The results show that the strength in the solid state tends to increase with decreasing temperature. The strain rate plays an important role in the stress–strain behaviors at higher temperatures, whereas the influence becomes less pronounced and irregular when the temperature is less than 250°C. The experimental data were fitted to the extended Ludwik equation, which is suitable to describe the mechanical behavior of the materials in the as-cast state. In the semi-solid state, both the strength and ductility of the alloy are high near the solidus temperature and decrease drastically with decreasing solid fraction. As the solid fraction is less than 0.97, the maximum strength only slightly decreases, whereas the post-peak ductility begins to increase. The experimental data were fitted to the modified creep law, which is used to describe the mechanical behavior of semi-solid materials, to determine the equivalent parameter f_GBWL, i.e., the fraction of grain boundaries covered by liquid phase.     

钢管混凝土梁柱节点受剪承载力计算模型分析

为了研究钢管混凝土梁柱节点受剪承载力,对钢管混凝土梁柱节点的剪切破坏机理进行了深入的讨论,分别对核心区混凝土、钢管以及加强环对节点的抗剪贡献进行了分析,提出了考虑轴压力、柱端弯矩、梁端竖向剪力等因素的梁柱节点受剪承载力计算模型,通过实例验证了公式的合理性。     

Mechanism research on arsenic removal from arsenopyrite ore during a sintering process

The mechanism of arsenic removal during a sintering process was investigated through experiments with a sintering pot and arsenic-bearing iron ore containing arsenopyrite; the corresponding chemical properties of the sinter were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The experimental results revealed that the reaction of arsenic removal is mainly related to the oxygen atmosphere and temperature. During the sintering process, arsenic could be removed in the ignition layer, the sinter layer, and the combustion zone. A portion of FeAsS reacted with excess oxygen to generate FeAsO₄, and the rest of the FeAsS reacted with oxygen to generate As₂O₃(g) and SO₂(g). A portion of As₂O₃(g) mixed with Al₂O₃ or CaO, which resulted in the formation of arsenates such as AlAsO₄ and Ca₃(AsO₄)₂, leading to arsenic residues in sintering products. The FeAsS component in the blending ore was difficult to decompose in the preliminary heating zone, the dry zone, or the bottom layer because of the relatively low temperatures; however, As₂O₃(g) that originated from the high-temperature zone could react with metal oxides, resulting in the formation of arsenate residues.     

一类非线性泛函微分方程多个正周期解的存在性

用A Very-Henderson不动点定理考虑一类带有时滞的泛函微分方程多个正周期解的存在性问题,得到此类方程存在多个正周期解的充分条件,并获得了这些正周期解的一些性质。在现有研究的基础上,推广了此类泛函微分方程的形式,放宽了存在多个正周期解这一结论成立的条件,扩大了正周期解存在性证明的适用范围。     

基于Markov模型的松嫩平原西南部土地盐碱化预测研究

摘要：以松嫩平原西南部土地盐碱化典型区之一的吉林省大安市为研究对象,该区土地盐碱化的主要动态变化因子是草地、耕地、水域、林地与盐碱地之间的转化,采用时间尺度为12年的1989年和2001年两期遥感影像,结合野外调查、各种图件和文字资料,利用GIS软件人机交互式解译提取大安市盐碱地、草地、耕地、水域、林地信息,获取统计数据,并以此为基础利用马尔柯夫模型预测和分析大安市未来10年土地利用格局的演化。结果表明。在保持当前人为干扰条件不变的情况下,2010年该区盐碱化土地面积占上述5种土地利用类型总面积的比例将达到38．67％,2015年将达到40．75％,土地盐碱化严重。因此,这一问题不容忽视,必须采取有效措施,维护该区生态环境的健康发展。图2,表4,参12。     

基于深度学习的白光-热成像双通道图像识别系统设计

为解决无人机图像自动识别系统对大视场角下小目标的识别准确率及实时性问题,利用深度学习卷积神经网络对热成像-白光联合图像进行目标识别。设计了一种针对具有温度特征的目标物识别系统以及双通道目标候选提名图像识别算法。充分利用热成像图中目标热源特征的HSV值,将目标物从热成像图中进行筛选、分割。通过Canny算子勾勒目标物轮廓,并标记出目标物大致区域,导入白光图像提取含有目标物的有效图像信息。利用YOLO V2算法对候选图像内目标物进行识别。通过实验表明,提出的双通道目标候选提名图像识别算法具有可行性与实用性,能够在大视场环境下对小目标进行精准快速识别,满足无人机机载系统简易、实时和准确性要求。