Application of artificial neural network method to predict the breakage properties of PGE bearing chromite ore

In the present investigation, systematic grinding experiments were conducted in a laboratory ball mill to determine the breakage properties of low-grade PGE bearing chromite ore. The population balance modeling technique was used to study the breakage parameters such as primary breakage distribution (B_{i, j}) and the specific rates of breakage (S_i). The breakage and selection function values were determined for six feed sizes. The results stated that the breakage follows the first-order grinding kinetics for all the feed sizes. It was observed that the coarser feed sizes exhibit higher selection function values than the finer feed size. Further, an artificial neural network was used to predict breakage characteristics of low-grade PGE bearing chromite ore. The predicted results obtained from the neural network modeling were close to the experimental results with a correlation of determination R² = 0.99 for both product size and selection function.     

Interconnected SiC–Si network reinforced Al–20Si composites fabricated by high pressure solidification

The microstructures and mechanical properties of the interconnected SiC–Si network reinforced Al–20Si composites solidified under high pressures were investigated. The results demonstrate that the complete interconnected SiC–Si network can be obtained by high pressure solidification, and the connected micron-sized pores are uniformly distributed in the interconnected SiC–Si network. The compressive strength and microhardness of the SiC/Al–20Si composites solidified under 3 GPa were 723 MPa and 229 HV_0.05, respectively. Furthermore, the fracture process of SiC/Al–20Si composites was studied by in situ TEM tensile testing. The result shows that the crack first initiated and propagated at the Al/Si interface under an external load, and the SiC particles in the interconnected SiC–Si network can effectively hinder the crack propagation, thus enhancing the strength.     

基于法律政策和检测性质的市县级食药检测机构整合探讨

本研究通过国家认证认可监督管理委员会发布的《2016年度检验检测服务业统计报告》相关数据,基于食品药品法律政策、检测性质、规模效应、检测能力建设等方面,对基层食品药品类检验检测资源整合路径进行论证分析。面对当前事业单位机构改革,本研究提出市县级食品药品类检验检测机构应进行跨行业、跨部门、跨层级优化整合的建议,建立以政府实验室为基础、市场检测为补充的食品药品安全检验检测资源配置模式,为实现基层食品药品安全监管现代化治理提供良好的检验检测技术服务支撑能力。     

卤水井测试工艺研究

卤水井测试的最大技术难题是井筒结晶堵塞问题。为解决这个问题,以四川邛崃平落坝构造高浓度卤水井测试为例,从卤水组分、温度、流速及管材等方面,分析卤水井开采测试中结晶产生的影响因素;从卤水的化学性质出发,探讨工具防腐技术;结合现场应用效果,进一步优化管柱结构。     

Blockchain verification and validation: Techniques,challenges, and research directions

As blockchain technology is gaining popularity in industry and society, solutions for Verification and Validation (V&V) of blockchain-based software applications (BC-Apps) have started gaining equal attention. To ensure that BC-Apps are properly developed before deployment, it is paramount to apply systematic V&V to verify their functional and non-functional requirements. While existing research aims at addressing the challenges of engineering BC-Apps by providing testing techniques and tools, blockchain-based software development is still an emerging research discipline, and therefore, best practices and tools for the V&V of BC-Apps are not yet sufficiently developed. In this paper, we provide a comprehensive survey on V&V solutions for BC-Apps. Specifically, using a layered approach, we synthesize V&V tools and techniques addressing different components at various layers of the BC-App stack, as well as across the whole stack. Next, we provide a discussion on the challenges associated with BC-App V&V, and summarize a set of future research directions based on the challenges and gaps identified in existing research work. Our study aims to highlight the importance of BC-App V&V and pave the way for a disciplined, testable, and verifiable BC development.     

检测实验室中标准物质的质量控制及管理

标准物质是保证准确量值和量值溯源的重要工具，标准物质的有效控制和管理是确保实验室检测数据准确的关键步骤，关系着实验室质量控制水平。对标准物质进行有效的管理控制，充分发挥标准物质的功能，是当前检测实验室急需解决的关键问题。本文主要探究了从标准物质的购买、验收及验证、储存管理、配制、标识、使用、期间核查、失效后处理等全过程进行系统地控制，保证标准物质的质量，确保标准物质在质量控制、校准测量仪器、评价测量分析方法、赋予物质特性量值、考核评价检测人员的技术能力、产品检测过程等方面起到重要作用，从而达到提高检测实验室检测数据的准确性和检测技术能力水平的目的。     

节理岩体爆破研究进展

实际的岩体都是被节理裂隙等弱面切割，对爆破效果有很重要的影响、本文在回顾并综合分析了节理岩体爆破理论和试验研究状况的基础上，对节理岩体的质量综合评价、力学模型的研究、数值模拟的研究、爆破块度的分析及理论与试验相结合等方面提出了几点看法。     

基于CPET时序聚类的中长跑耐力运动员选拔方法

心肺运动试验（CPET）能将人体的呼吸系统、心血管系统等综合为一体，不仅能够体现受试者的有氧运动能力，评估受试者的心肺耐力，而且能以整体整合医学的视角来研究受试者对运动的应激反应。为对CPET数据进行凝聚层次聚类分析，提出一种基于时间序列形态特征的算法。选取15名业余中长跑运动员的CPET数据作为聚类对象，聚类指标选取了表征有氧能力和心肺耐量的耗氧量、二氧化碳、心率、分钟通气当量、代谢当量、生理死腔与潮气量比值、呼吸商及每搏输出量等8类指标，体现运动员摄取、利用氧的效率、肺循环以及心功能等综合状况。通过聚类分析发现受试者个体差异较大，未出现明显的“群居分布”特征，根据轮廓系数评估可剔除心肺耐量较差的测试者。实验结果表明，该算法在确保聚类准确率的同时能够降低数据压缩率，且对形态特征显著的数据集进行聚类效果更佳。     

带式输送机测试台的研制

介绍了一种带式输送机性能测试台，论述了研制该装置的目的和设计思想，介绍了该装置的结构组成及在科研上的使用。利用该装置可以测试带式输送机多方面的性能参数。