尘埃粒子计数器的检测和校准现状

尘埃粒子计数器是用来评价洁净环境洁净度等级的重要仪器,近年来,尘埃粒子计数器的量值溯源一直是国内外计量机构的研究重点,目前被广泛认可的尘埃粒子计数器的溯源方法有两种:一是采用参加全国比对的尘埃粒子计数器与待检尘埃粒子计数器进行比对;另一种是通过凝结核粒子计数器溯源至气溶胶静电计,最终溯源至计量基准电流之上。本文将综述尘埃粒子计数器的检测和校准方法以及存在问题。     

尘埃粒子计数器的校准

本文主要介绍了尘埃粒子计数器的调校方法和校准过程中遇到的问题。     

尘埃粒子计数器校准装置的研制

采用“尘埃粒子计数器-凝结核粒子计数器-气溶胶静电计”的逐级溯源方法,开展了尘埃粒子计数器校准装置的研制。首先采用可溯源至国家电阻及电压标准的高值电阻和直流电压源,对气溶胶静电计的响应电流进行了校准;之后利用比对法和稀释技术,对凝结核粒子计数器进行了校准研究,最后将凝结核粒子计数器作为量值传递标准,通过比对法实现对尘埃粒子计数器的校准,校准结果可溯源至国家电流标准。     

浅析尘埃粒子计数器的量值溯源

随着尘埃粒子计数器在各行各业的广泛利用,为保证测量结果的准确可靠,必须对尘埃粒子计数器有效溯源。本文从目前国内外有关的尘埃粒子计数器技术标准出发,详细分析其溯源现状,并探讨进一步的研究方向,供有关计量科研人员参考。     

尘埃粒子计数器的校准方法

尘埃粒子计数器主要用来评定洁净室洁净度等级、检测过滤器的过滤效率及洁净织物的发尘量等。尘埃粒子计数器的量值溯源因其特殊性,存在很大难度,多年来国内外都在致力于尘埃粒子计数器的校准研究。该文就研究以及编写的尘埃粒子计数器国家计量校准规范,来阐述尘埃粒子计数器的校准方法。     

尘埃粒子计数器校准系统的改造

本文主要介绍了尘埃粒子计数器校准系统改造方案的研究方案和改造过程中遇到的问题。     

尘埃粒子计数器校准结果及其应用探讨

本文对尘埃粒子计数器粒子浓度示值误差校准结果的计算进行了讨论,并以制药行业中尘埃粒子计数器的使用为例对尘埃粒子计数器校准结果的应用进行了探讨。     

尘埃粒子计数器宏粒子发生装置的研制

尘埃粒子计数器是用于检测评价洁净环境洁净度等级的仪器.目前,尘埃粒子计数器的溯源主要通过全国比对的方式对0.5μm的粒子浓度进行溯源,但制药、医疗器械等行业还普遍关注5.0μm粒径通道的计数准确性,然而5.0μm的粒径通道校准却存在气溶胶发生器浓度难控制、单分散性差的难题.本文针对这一技术难题,研制了一款针对尘埃粒子计...     

尘埃粒子计数器标准粒子信号幅度分布统计分析

为了研究激光尘埃粒子计数器标准粒子信号幅度分布,对激光尘埃粒子计数器计数信号幅度分布与传感器光敏区光强分布、采样气流中的粒子数密度、气体层流速度分布之间的关系进行了理论分析.采用自设计的带保护气套的光电传感器测定粒子计数信号幅度分布,给出的分布模型与理论分析相吻合.结果表明,尘埃粒子计数器标准粒子信号幅度分布满足对数正态分布,描述其分布的参数σ只与光敏区光强的均匀性有关.这为尘埃粒子计数器的设计提供了理论依据.     

激光尘埃粒子计数器浓度上限的标定

计数浓度上限是激光粒子计数器的重要性能指标之一。本文对各国标准中激光尘埃粒子计数器浓度上限的标定方法进行了分析比较。并提出了一种经济便捷,适合国内计数器行业现状的浓度上限标定方法。     

基于DSP技术的在线颗粒计数器

颗粒计数器已逐渐应用于水质检测中。本文介绍了基于光阻法颗粒计数器的基本原理，并设计了基于DSP芯片技术的主从机系统，从而提高了颗粒检测的分辨率。文中还给出了相应的控制框图以及信号处理的方法。     

尘埃粒子计数器校准结果量值溯源

通过对尘埃粒子计数器校准原理的研究分析,确定了与尘埃粒子计数器校准结果直接相关的量值颗粒尺寸和颗粒数量,并对颗粒尺寸及其颗粒数量的溯源性进行了分析,理顺了量值溯源与传递体系的关系,保证了尘埃粒子计数器校准结果的准确可靠。     

Effect of model details on the predicted saturation profiles in condensation particle counters

We establish an analytical model, as well as perform Computational Fluid Dynamics (CFD) simulations to investigate the evaporation-condensation process in Condensation Particle Counters (CPCs). Via a systematic analysis of the effect of geometrical and operational parameters on the saturation profile in CPCs, we unveil that the insulation in these measurement devices is of key significance for the detection efficiency. Furthermore, we demonstrate that our analytical model can reliably predict the mass fraction of working fluid in the gas phase at the outlet of the saturator. This is of key importance for the efficient screening of working fluids, as well as the optimization of both geometry and operation parameters of CPCs.     

Preliminary calibration of the ACP safeguards neutron counter

The Advanced Spent Fuel Conditioning Process (ACP), a kind of pyroprocess, has been developed at the Korea Atomic Energy Research Institute (KAERI). Since there is no IAEA safeguards criteria for this process, KAERI has developed a neutron coincidence counter to make it possible to perform a material control and accounting (MC&A) for its ACP materials for the purpose of a transparency in the peaceful uses of nuclear materials at KAERI. The test results of the ACP Safeguards Neutron Counter (ASNC) show a satisfactory performance for the Doubles count measurement with a low measurement error for its cylindrical sample cavity. The neutron detection efficiency is about 21% with an error of ±1.32% along the axial direction of the cavity. Using two ²⁵²Cf neutron sources, we obtained various parameters for the Singles and Doubles rates for the ASNC. The Singles, Doubles, and Triples rates for a ²⁵²Cf point source were obtained by using the MCNPX code and the results for the ft8 cap multiplicity tally option with the values of ε, f_d, and f_t measured with a strong source most closely match the measurement results to within a 1% error. A preliminary calibration curve for the ASNC was generated by using the point model equation relationship between ²⁴⁴Cm and ²⁵²Cf and the calibration coefficient for the non-multiplying sample is 2.78×10⁵ (Doubles counts/s/g ²⁴⁴Cm). The preliminary calibration curves for the ACP samples were also obtained by using an MCNPX simulation. A neutron multiplication influence on an increase of the Doubles rate for a metal ingot and UO2 powder is clearly observed. These calibration curves will be modified and complemented, when hot calibration samples become available. To verify the validity of this calibration curve, a measurement of spent fuel standards for a known ²⁴⁴Cm mass will be performed in the near future.     

Large area dye-sensitized solar cells with titanium based counter electrode

Construction of dye-sensitized solar cell of large area using platinum sputtered titanium metal counter electrode is demonstrated. An impressive increase in the fill factor and consequently the efficiency compared to the conventional platinized conducting glass based counter electrodes result from very low sheet resistance of the titanium plate and a cell of active area 151 cm² with parallel silver collecting grids delivered an efficiency of 7.4%. The possibility of using this technique for commercial production of dye-sensitized solar cells was discussed giving details of fabrication procedure.     

基于稳态运行模式影响NBI真空空间粒子分布特性的研究

EAST-NBI真空空间粒子分布状态是影响中性束再电离损失的重要因素,是研究EAST-NBI系统的结构设计和提高加热效率的重要课题。根据EAST-NBI的工作原理、结构特点以及系统的气源特性,利用Monte-Carlo方法建立模型,运用Matlab软件对EAST-NBI稳态运行模式下真空空间内任意时刻的粒子分布进行编程模拟计算。研究结果表明气源的种类、气体量大小和气体粒子的发射方向是影响EAST-NBI真空空间粒子分布的主要因素,为减小再电离损失、提高加热效率和EAST-NBI的研制提供理论依据。     

染料敏化太阳电池新型介孔碳对电极的制备及性能研究

以三嵌段共聚物F127为模板剂制备介孔碳,并用N2吸附和透射电子显微镜对介孔碳样品进行分析.所制备介孔碳材料的孔呈无序蠕虫状,平均孔径为6.8nm,比表面积为400m2/g.用介孔碳作为I(-)/I(-)3氧化还原反应的催化剂制备染料敏化太阳电池对电极,用电化学阻抗谱对介孔碳电极的催化活性进行了分析.介孔碳电极对I(-...     

染料敏化太阳电池中铂金对电极的制备及性能之比较

分别采用了3种不同的方法制备了用于染料敏化TiO2太阳电池的铂金对电极，并分别以此3种铂金对电极组装染料敏化太阳电池，对比、分析和探讨了它们对光电转化性能的影响。结果表明：采用纳米粒子电沉积法与电化学电镀法制备的铂金对电极，具有较高的催化活性，以这两种方法制备的铂金对电极组装的DSSCs获得较好的光电转化性能，电池的光电转化效率分别为6．40％和6．63％，且采用纳米粒子电沉积法制备的铂金对电极铂金含量较低；而采用热分解法制备的铂金对电极来组装的DSSCs获得的光电性能相对较低，电池效率为5．58％。     

高温气冷堆燃料装卸系统计数器电路改进设计

对10MW高温气冷堆(HTR-10)燃料装卸计数系统中采用涡流传感原理设计的原有计数器进行了优化--将原来的恒压源激励改进为恒流源激励,并且激励源的幅值和频率均变为可调,以提高系统的性能.对改进电路的实验电路板进行了在线实验,实验表明,改进的计数器计数准确,充分适应现场情况的复杂性,并增加了传感器的灵敏度,提高了系统的可靠性.