改善加热不燃烧型烟草薄片物理性能的研究

加热不燃烧型烟草薄片是一种新型烟草薄片,其制备方法主要包括稠浆法、辊压法、造纸法。为保证烟草薄片的良好成形及耐加工性,需添加一定量的木浆纤维。本研究探究了木浆纤维在稠浆法加热不燃烧型烟草薄片中的应用,考察了木浆纤维打浆度和添加量对稠浆性能和烟草薄片物理性能的影响。研究表明,增加木浆纤维打浆度有利于降低稠浆黏度,木浆纤维的打浆度为49 °SR时,烟草薄片的力学性能相对较好;木浆纤维添加量在2%~5%时,烟草薄片力学强度随着木浆添加量的增加而增加,抗张指数最高可达3.62 N·m/g。     

两起电容式电压互感器故障的分析与处理

阐述电容式电压互感器(Capacitor Voltage Transformer,CVT)的基本结构和工作原理,分析了掌握CVT健康度的方法和试验项目.首先,以两起运行中CVT的试验数据异常为例,通过对设备结构、试验原理的分析,对各项试验数据进行了说明.其次,介绍了试验人员通过缩短试验周期、分析试验数据、结合运行实际等...     

耐高温腐乳毛霉菌种选育及产酶条件研究

以毛霉M263为出发菌株，经紫外线，γ—射线及高温热处理复合诱变，并采用高温培养条件定向驯化，获得一株耐高温毛霉菌株M263-3，在32℃条件下，生长正常，酿制的腐乳质量优良。对毛霉M263-3的培养基及产酶条件进行试验，在最佳培养基及较适宜培养条件下，毛霉M263-3中性蛋白酶活力为830ug／min。     

纯棉细平布纬向缩水率的研究

介绍了解决纯棉细平布纬向缩水的方法。通过严格控制丝光和拉宽等工序工艺条件,从而提高纯棉细平布的纬向缩水质量。     

一般通风用空气过滤器常用检测标准对比研究

对一般通风用空气过滤器性能检测常用的三大标准(ANSI/ASHRAE standard52.2、EN 779和GB/T 14295)分别进行了全面的介绍,并通过比较分析揭示了各个标准的优缺点,对空气过滤器性能检测试验台的建设和使用有很好的指导作用。     

钢结构住宅特点评析

从住宅体系、结构特点、经济和可变性等方面,对钢结构住宅的特点进行了评析。     

浅谈土地测绘手段中的技术进步

随着测绘手段的发展,土地测量方法在不断的更新,使得土地测量效率提高,数据越来越精确。     

Study on the influence of three-grid assembly thermal deformation on breakdown times and an ion extraction process

In order to study the influence of three-grid assembly thermal deformation caused by heat accumulation on breakdown times and an ion extraction process,a hot gap test and a breakdown time test are carried out to obtain thermal deformation of the grids when the thruster is in 5 k W operation mode.Meanwhile,the fluid simulation method and particle-in-cell-Monte Carlo collision(PICMCC) method are adopted to simulate the ion extraction process according to the previous test results.The numerical calculation results are verified by the ion thruster performance test.The results show that after about 1.2 h operation,the hot gap between the screen grid and the accelerator grid reduce to 0.25–0.3 mm,while the hot gap between the accelerator grid and the decelerator grid increase from 1 mm to about 1.4 mm when the grids reach thermal equilibrium,and the hot gap is almost unchanged.In addition,the breakdown times experiment shows that 0.26 mm is the minimal safe hot gap for the grid assembly as the breakdown times improves significantly when the gap is smaller than this value.Fluid simulation results show that the plasma density of the screen grid is in the range 6?×10~(17)–6?×?10~(18) m~(13) and displays a parabolic characteristic,while the electron temperature gradually increases along the axial direction.The PIC-MCC results show that the current falling of an ion beam through a single aperture is significant.Meanwhile,the intercepted current of the accelerator grid and the decelerator grid both increase with the change in the hot gap.The ion beam current has optimal perveance status without thermal deformation,and the intercepted current of the accelerator grid and the decelerator grid are 3.65 m A and 6.26 m A,respectively.Furthermore,under the effect of thermal deformation,the ion beam current has over-perveance status,and the intercepted current of the accelerator grid and the decelerator grid are 10.46 m A and 18.24 m A,respectively.Performance test results indicate that the breakdown times increase obviously.The intercepted current of the accelerator grid and the decelerator grid increases to 13 m A and 16.5 m A,respectively,due to the change in the hot gap after 1.5 h operation.The numerical calculation results are well consistent with performance test results,and the error comes mainly from the test uncertainty of the hot gap.     

分压电流对7.62 cm光电倍增管性能的影响

7.62 cm(3英寸)光电倍增管(Photomultiplier Tube,PMT)是江门中微子实验(Jiangmen Underground Neutrino Observatory,JUNO)巨型探测器的重要组成部分,以此构成的一套独立探测系统,承担着独立物理测量、与50.8 cm(20英寸)PMT探测系统相互检验等重要任务。为提高探测系统的可靠性,使每个7.62 cm PMT供电高压的单通道电流不超过10?A,研究了不同高压电流对7.62 cm PMT探测性能的影响。采用三种高压电流的分压器,对海南展创生产的型号为XP72B20(样管编号为70069)的7.62 cm PMT的性能进行实验测试,包括增益、能量分辨率、峰谷比和阳极输出信号的非线性。结果表明:不同分压电流对7.62 cm PMT性能的影响较小。这个结果为该7.62 cm PMT在JUNO探测器中使用小分压电流的方案提供了重要的实验依据。     

分层开采底板岩体渗透性变化的试验研究

华北煤田石炭二叠纪煤系地层底部存在着含水丰富的奥陶纪石灰岩。开采实践表明,一旦煤层与奥灰之间的隔水层内存在地质构造或煤层开采引志底板岩体破坏,可能会在煤层和含水层之间形成导水带,从而诱发突水,介绍了分层开采引起对底板岩石渗透性影响的试验成果,并进行了详尽的分析,获得了分层开采对煤层底板岩体渗透性的影响规律。