一致性区间数判断矩阵及其性质

本文给出一致性区间数判断矩阵的定义及一致性区间数判断矩阵的一些性质。     

可食性昆虫的营养价值和食用安全性研究进展

昆虫是地球上种类丰富、数量繁多的自然资源。可食性昆虫在中国具有悠久的历史,已日渐成为人类重要的食品资源之一。通过查阅文献统计,我国可食性昆虫有324种,共分为11个目,其中鳞翅目、鞘翅目和膜翅目包含可食性昆虫种类居多。可食性昆虫不仅可以补充必需营养素,还能够补充微量元素。因此,营养丰富的可食性昆虫资源不仅可以扩大人类对食物的选择范围,还可以作为一种替代食物来源。本文从可食性昆虫蛋白质含量、脂肪含量、矿物质等方面介绍其营养价值,从食品安全、营养价值以及潜在的环境影响等方面总结了近年来可食性昆虫的安全性评价进展,探讨可食性昆虫作为新型食品的开发前景及挑战,提出了可食性昆虫食品目前所存在的问题,为可食性昆虫的后续研究及开发提供参考。     

佩戴防尘口罩对吸入气溶胶粒度影响的实验研究

本文介绍了应用级联撞击器和佩戴口罩的人头模型在天然铀燃料元件加工现场测定吸入气溶胶粒度的方法。结果表明,佩戴口罩使得吸入气溶胶的活度中值空气动力学直径(AMAD)变小,并且吸入气溶胶的 AMAD 值与场所气溶胶的 AMAD 值有一定关系,粒径分布类型也发生改变。文中还报告了口罩的漏过率有随微尘粒径减小而增大的趋势。实验结果对内照射剂量估算以及评价口罩的防尘能力有一定的参考价值。     

添加ZrO2对铜基摩擦材料摩擦磨损性能的影响

采用粉末冶金方法制备了高速列车用铜基摩擦材料,研究了添加ZrO2的量对材料的摩擦因数、磨损量的影响规律。结果表明:在添加ZrO2的材料中,含5%(质量分数,下同)ZrO2的材料摩擦因数较高,磨损量也较大;添加8%ZrO2的材料在高速下的摩擦因数较高,磨损率较小且变化平稳。材料的磨损在较低的速度下以粘着磨损为主;随着速度的上升,磨损也逐渐变成以剥层脱落和氧化磨损的混合机制为主。     

无动力快速浮选在山东某黄金矿山的应用

山东某黄金矿山选矿厂由于浮选工艺流程中旋流器与取样机之间高差较大,以致溢流矿浆流速快、动能大,易造成对管路、弯头及取样机缓冲箱的冲击磨损。鉴于此,在旋流器溢流进入浮选粗选前增加快速浮选槽,以充分利用矿浆的动能,将原浮选工艺流程前增设无动力快速浮选工艺,并对改造后工艺流程结构进行了优化,将原三次扫选改为二次扫选。无动力快速浮选工艺的应用,不但节约了能耗,而且提高了金回收率,其由改造前的91.69%提高到93.06%,生产指标较好。     

拔染剂的应用性能研究

综合分析了三种拔染剂在拔染浆中的稳定性、吸湿性和渗透性等应用性能，并得出一些重要结论。     

嵌入式Web服务器的设计与实现

为解决远程访问、监测并控制嵌入式设备的需求,提出了基于Boa和CGI技术构建Web服务器的思想.在论证整体设计方案的基础上,以S3C2410处理器为硬件核心,以ARMLinux为操作系统平台,设计了嵌入式Web服务器,给出了系统的硬件结构组成.介绍了ARM Linux操作系统的移植过程,着重分析了Boa服务器的构建以及CGI应用扩展开发.最后对构建好的嵌入式Web服务器进行了运行测试,测试结果表明其运行稳定、控制方便、响应迅速,达到了预期的设计目的.     

基于Web服务的数字化校园统一身份认证系统研究

通过对数字化校园网络应用传统统一身份认证和资源访问控制机制不足之处的分析,提出了一种基于Web服务的统一身份认证系统模型,并采用基于票据的集中式架构,以跨域Cookie共享为核心来完成用户的登录、认证和权限控制。实例证明,此方案可以方便的将分散网络节点加入认证体系,完成网络节点单点登录和资源访问控制问题。     

Orientationability analyses of a special class of the Stewart–Gough parallel manipulators using the unit quaternion representation

This paper addresses the orientation-singularity and orientationability analyses of a special class of the Stewart–Gough parallel manipulators whose moving and base platforms are two similar semi-symmetrical hexagons. Employing a unit quaternion to represent the orientation of the moving platform, an analytical expression representing the singularity locus of this class of parallel manipulators in a six-dimensional Cartesian space is obtained. It shows that for a given orientation, the position-singularity locus is a cubic polynomial expression in the moving platform position parameters, and for a given position, the orientation-singularity locus is an analytical expression but not a polynomial directly with respect to the mobile platform orientation parameters. Further inspection shows that for the special class of parallel manipulators, there must exist a nonsingular orientation void in the orientation space around the orientation origin for each position in the position-workspace. Therefore, a new performance index referred to as orientationability is introduced to describe the orientation capability of the special class of manipulators at a given position. A discretization algorithm is proposed for the computation of the orientationability of the special class of manipulators. Moreover, effects of the design parameters and position parameters on the orientationability are investigated in details. Based on the orientationability performance index, another novel performance index referred to as practical orientationability is presented which represents the practical orientation capability of the manipulator at a given position. The practical orientationability not only can satisfy all the kinematic demands and constraints of such class of manipulators, but also can guarantee that the manipulator is nonsingular.     

Broadband MIMO Antenna System for 5G Operations in Mobile Phones

A broadband 8‐antenna multiple‐input and multiple‐output (MIMO) system working for 5G new radio N77 (3.3‐4.2 GHz) in mobile terminals is proposed. In particular, each antenna element/unit consists of a monopole‐type meandered branch and an inverted U‐shaped self‐isolated antenna branch; and the antenna unit is fed by the meandered branch. The antenna unit has two resonances generated separately by each branch of the antenna unit. Since the monopole couples strongly with the self‐isolated antenna element that has the inherent self‐isolation characteristics, quite good isolation for the broadband 8‐antenna MIMO system can be obtained. The results such as antenna efficiency, radiation patterns, envelope correlation coefficient, and channel capacity are also presented.