宝泉抽水蓄能电站500 kV GIS设备安装

宝泉抽水蓄能电站500kVGIS设备安装是整个电站机电安装中的关键项目之一,具有设备体积大、安装工艺复杂、施工工期长等特点,从实用角度出发,分别介绍GIS安装准备工作、设备安装、气体作业等内容和方法,并进行了总结。     

近期中欧纺织品贸易摩擦分析

历经几个月的中欧纺织品贸易摩擦经过双方的多次谈判及努力,终于顺利解决。但是,这次纺织品贸易摩擦产生的原因究竟是什么?对我国的社会和经济发展有何种影响?通过这次贸易摩擦应汲取何种经验教训?文章通过对我国纺织品对外贸易的现状及产生摩擦的原因进行分析,并对今后我国纺织品贸易的发展提出了建议。     

基于容量相关字典的5G毫米波大规模天线单元选择算法

针对传统天线选择算法在大规模天线阵列应用中的局限性,该文在多用户场景下提出一种基于容量相关字典的5G毫米波大规模天线随机选择算法。该算法通过特定环境中不同位置处的多用户与基站的交互,快速提取大规模天线单元间容量的强弱相关特性,并建立相关字典;在天线选择时,先搜索最优信道容量单元连接射频链路,再随机选择相关字典中与最优单元容量相关大的天线单元接入其余射频链路。该方法大大降低了传统天线选择算法应用的复杂度,只与环境有关且较为稳定,当新用户加入时也无需重新建立相关字典。该方法通过损失一部分性能来换取较低的复杂度,适用于天线单元多的大规模天线阵列。此外,该文在室内开放式办公室开展了26 GHz视距和非视距下的大规模天线信道测试,分析了不同场景下的天线阵列行间单元间的容量相关性,并对该算法的系统信道容量性能进行了实验验证。     

风速数字测量

文中介绍基于AT89C51单片机的风速数字测量方法,描述电路设计和软件实现,实验证明有较高精度.     

大数据时代的珠宝品牌构建

纵观当代,世界已然进入到一个具有极大数据量的互联网"云时代"。而大数据的运用也日渐成为商业焦点之一。所谓大数据,即需要运用新的处理模式才能具有的更强决策力、洞察发现力和流程优化能力的海量、高增长率和多样化的信息资产。因此,如何在现有的大数据环境下利用已有的大数据引擎构建强效的珠宝品牌并进行相应的品牌营销等问题便赫然屹立在每一个现代珠宝商的面前。本文从当下中国珠宝行业市场现状分析入手,探寻其中的利弊得失,试图利用大数据的品牌营销方式对未来中国珠宝品牌的建设提供可行的发展方向。     

全开放MR导航下经皮腹膜后肿块同轴穿刺活检的临床应用

【摘要】 目的 探讨全开放MR导航系统辅助下经皮腹膜后肿块同轴穿刺活检术的效果和安全性。方法 回顾性分析2014年1月—2018年12月81例MR导航下腹膜后肿块穿刺活检的病例。均采用磁兼容16 G活检套筒针穿刺,当套筒针尖到达目标穿刺区域时,采用同轴活检枪通过套筒针活检取材。穿刺活检成功的标准为取出完整的长条状组织。若活检失败调整穿刺套筒针,继续取材,直到取出完整的长条状组织。结果 81例穿刺均顺利完成,总体穿刺活检成功率100%（81/81）,其中1次穿刺活检成功率91.4%（74/81）。穿刺诊断准确率为97.5%（79/81）。47例采取经皮腹侧入路穿刺,34例采取经皮背侧入路穿刺,6例经皮经肝入路穿刺,无经胃肠及肾穿刺病例。平均手术时间为（28.2 ±5.5） min。术后无腹腔活动性出血、腹膜后血肿及肠穿孔等不良事件发生,2例患者WTO疼痛分级Ⅱ级,予以止痛对症支持治疗后缓解。结论 全开放MR导航下经皮腹膜后肿块穿刺活检术是一种精确而安全有效的诊断技术,且无辐射伤害,值得临床上推广。

     

~(99)Tc~m-半乳糖基化人血清白蛋白融合干扰素α2b的制备和生物分布

用氯化亚锡(SnCl2)还原法制备99Tcm-半乳糖基化人血清白蛋白融合干扰素α2b(GHSA-IFNα2b),研究了SnCl2和GHSA-IFNα2b的用量以及溶液pH对99Tcm-GHSA-IFNα2b标记率的影响;ICR小鼠尾静脉注射99Tcm-GHSA-IFNα2b(0.286MBq/只,n=6),于5、10、15、30、60、120min取脏器和血,称重、计数,计算%ID(organ)-1和%ID·g-1;并对99Tcm-GHSA-IFNα2b的SD大鼠显像进行了研究.结果表明,在pH=3.0～4.5、GHSA-IFNα2b的用量≥0.3 mg、SnCl2的用量为3～60 μg时,37℃反应30 min,可得标记率＞90%的99Tcm-GHSA-IFNαt2b,并在6 h内保持基本稳定;肝脏组织中的99Tcm-GHSA-IFNα2b在注射后10 min高达52.51%ID(organ)-1,能够被肝脏特异性摄取,主要通过胆道、肠道排泄;大鼠静脉注射15～30 min时,即可获得清晰的肝显像.     

Metasurface: Enhancing gain of antenna and energy harvesting system design

The metasurface technique has been applied to enhancing the gain and directivity of antenna in this paper. The normal metal ground is replaced by one metasurface structure to suppress the higher frequency component transmission. Another similar metasurface structure is put nearer to the antenna to increase gain and enhance directivity further. A low‐pass filter with defected ground plane is designed to obtain steeper falling edges and a wider stop band. Then a rectifier circuit is designed for the electromagnetic energy of input terminal converted into a DC output. The three parts of passive circuit make up a complete energy receiving system. The measured results of the system shown that the output voltage stable.     

Heat transfer enhancement with mixing vane spacers using the field synergy principle

The single-phase heat transfer characteristics in a PWR fuel assembly are important. Many investigations attempt to obtain the heat transfer characteristics by studying the flow features in a 5×5 rod bundle with a spacer grid. The field synergy principle is used to discuss the mechanism of heat transfer enhancement using mixing vanes according to computational fluid dynamics results, including a spacer grid without mixing vanes, one with a split mixing vane, and one with a separate mixing vane. The results show that the field synergy principle is feasible to explain the mechanism of heat transfer enhancement in a fuel assembly. The enhancement in subchannels is more effective than on the rod's surface. If the pressure loss is ignored, the performance of the split mixing vane is superior to the separate mixing vane based on the enhanced heat transfer. Increasing the blending angle of the split mixing vane improves heat transfer enhancement, the maximum of which is 7.1%. Increasing the blending angle of the separate mixing vane did not significantly enhance heat transfer in the rod bundle, and even prevented heat transfer at a blending angle of 50°. This finding testifies to the feasibility of predicting heat transfer in a rod bundle with a spacer grid by field synergy, and upon comparison with analyzed flow features only, the field synergy method may provide more accurate guidance for optimizing the use of mixing vanes.