掘进机截割头钻速优化分析

文章基于EBZ120型悬臂式掘进机进行截割临界转速分析优化,通过利用微元法和弹性力学建立力学模型,确定临界状态下,截割头转速解析解,然后深入分析影响截割转速的因素,依据影响程序确定影响介个转速的因素次序,为截割临界转速的确定提供实际操作提供依据。     

5G核心网业务模型的智能化预测研究

摘 要：核心网业务模型的建立是5G网络容量规划和网络建设的基础，通过现有方法得到的理论业务模型是静态不可变的且与实际网络存在偏离。为了克服现有5G核心网业务模型与现网模型适配性较差以及规划设备无法满足用户实际业务需求的问题，提出了一种长短期记忆（long short-term memory，LSTM）网络与卷积LSTM （convolution LSTM，ConvLSTM）网络双通道融合的 5G 核心网业务模型预测方法。该方法基于人工智能（artificial intelligence，AI）技术以实现高质量的核心网业务模型的智能预测，形成数据反馈闭环，实现网络自优化调整，助力网络智能化建设。     

复杂环形内悬空空间网格结构施工卸载优化

为解决麦积山景区游客服务中心项目的卸载施工难题，选取合理的卸载方法，文中借助了有限元软件对拟定的4种卸载方案进行了模拟分析，分别从关键节点的位移变形、结构杆件的最大应力变化、主体结构的支撑体系受力转变、临时支撑的最大反力变化、临时支撑的总反力几个方面优选出了最佳的卸载方案。结果表明内至外卸载方案下，卸载的动态最为平稳，有利于结构和临时支撑的稳定，为最优卸载方案。其相应的分析过程和分析结果都能为类似结构的安全卸载施工提供相关指导和借鉴。     

一种最小变形度全景视频映射方法

全景视频需要经过采样映射转换成平面矩形视频,以便后续的压缩编码.针对现有映射方法存在的内容变形和采样不均匀问题,提出一种最小变形度映射方法(Minimum Deformation Projection,MDP).首先提出新的变形度计算公式求得最优解,其次结合像素排列为矩形的要求和人工边界等因素对最优解做近似,最后得到了最优的多边形映射形状和像素排列方案.实验数据表明,MDP的采样密度更均匀,结合使用x265,相对于ERP可以获得约14.47％的增益,优于其他映射方法.     

Synthesis of Hollow Three-Dimensional Channels LiNi_(0.5)Mn_(1.5)O_4 Microsphere by PEO Soft Template Assisted with Solvothermal Method

A appropriate size with three-dimension(3 D) channels for lithium diffusion plays an important role in constructing highperforming LiNi_(0.5)Mn_(1.5)O_4(LNMO) cathode materials, as it can not only reduce the transport path of lithium ions and electrons, but also reduce the side effects and withstand the structural strain in the process of repetitive Li~+ intercalation/deintercalation. In this work, an e fficient method for designing the hollow LNMO microsphere with 3 D channels structure by using polyethylene oxide(PEO) as soft template agent assisted solvothermal method is proposed. Experimental results indicate that PEO can make the reagents mingle evenly and nucleate slowly in the solvothermal process, thus obtaining a homogeneous distribution of carbonate precursors. In the final LNMO products, the hollow 3 D channels structure obtained by the decomposition of PEO and carbonate precursor in the calcination can provide abundant electroactive zones and electron/ion transport paths during the charge/discharge process, which benefits to improve the cycling performance and rate capability. The LNMO prepared by adding 1 g PEO possesses the most outstanding electrochemical performance, which presented an excellent discharge capacity of 143.1 mAh g~(-1) at 0.1 C and with a capacity retention of 92.2% after 100 cycles at 1 C. The superior performance attributed to the 3 D channels structure of hollow microspheres, which provide uninterrupted conductive systems and therefore achieve the stable transfer for electron/ion.     

Research advances in residual thermal stress of ceramic/metal brazes

Brazing, as a common method of bonding ceramic and metal, has been applied in microelectronics, aerospace, machinery and other domains extensively. The residual thermal stress in the brazed joint has direct effects on the mechanical properties of the joint, so how to control the generation of residual thermal stress has become the vital point. In this paper, the methods of reducing residual thermal stress in the brazing process in recent years are reviewed. The generation and effects of residual thermal stress in the brazed joint are introduced. Besides, the methods of detecting residual thermal stress are discussed, and different methods of reducing residual thermal stress in brazed joints are also analyzed. Finally, the future development directions of reducing residual thermal stress in the brazed joint are proposed.     

固相萃取结合气相色谱-三重四极杆质谱法测定方便面中16种多环芳烃

建立固相萃取-气相色谱-三重四极杆质谱测定方便面中16种多环芳烃的方法。方便面样品用正己烷和乙腈-丙酮提取,经Oasis HLB和Florisil柱两步净化,气相色谱-三重四极杆质谱检测。在试验浓度范围内,线性关系良好,各种多环芳烃的定量限在0.03μg/kg^0.54μg/kg之间。在不同的加标浓度下,加标回收率在75%~129%之间,相对标准偏差小于13.4%。该方法快速、准确、灵敏度高、重现性好,适用于大批量样品中多环芳烃的快速测定。     

考虑需求响应的智能微电网日前竞价方案

由于发电、负荷和市场价格预测的不确定性，微电网日前竞价往往很困难。提出了采用2阶段随机规划的方法，通过蒙特卡罗模拟生成各种随机场景，并基于Kantorovich距离进行场景简化，以日前电力市场交易所获得的预期利润最大化为优化目标，计算了智能微电网能源管理系统对日前电力市场的最优报价，并将目标函数的非线性项重构成线性形式。仿真结果验证了所提方案在智能微电网日前竞价中具有很好的效果。