The use of RuO<Subscript>2</Subscript> resistors as broadband low-temperature radiation sensors

The possibility of using commercial RuO₂ planar resistors as low-temperature radiation sensors was investigated. At temperatures of 0.08–0.1 K, their sensitivity to blackbody radiation at temperatures of 5–40 K was about 2–3 pW. The radiation absorption coefficient was <10%. The response is a linear function of the radiation power, thus indicating that the detector band is no narrower than 0.5–2.5 THz. The rise time of an output signal without feedback-assisted temperature stabilization was ~12 s owing to an unexpectedly high thermal capacity of the resistor.     

勇克--精密磨削的伙伴

勇克集团:世界范围的专业化勇克集团是一个强大的共同体。约1000个员工在全世界9个地点从事开发、销售和生产工作。超过80项专利证实了企业的技术优势。这方面最好的例子是点磨工艺和用CBN及金刚石砂轮高速磨削。有活力的全球化在勇克销售、咨询和服务遍布全球。有经验的Key-Aceount管理人员满足用户专门的个别需要。在全世界所有重要工业区的服务支援站和呼叫中心确保最快速的支持。根据需要勇克在全世界所有需要的地方为用户提供专家。在几乎所有领域提供解决问题的方案在汽车和工具行业,勇克根据用户的需要提供在精密磨削加工的几乎所…     

New Kerr cell for low-temperature measurements

A Kerr cell has been constructed which can be used to study the Kerr effect in liquids from room temperature down to 77 K. At low temperatures, the cell windows are free of moisture. The cell has been tested and measurements on liquid carbon disulfide, between 170 and 300 K, are discussed.     

Gravitational capillary viscometer for low-temperature liquids

A pressurized gravitational capillary viscometer was developed for subcooled liquefied gases such as oxygen, nitrogen, hydrogen, and methane. It acquires accurate absolute viscosity measurements with an uncertainty of 1% at a 95.5% confidence level, necessary for the demands of aerospace engineering. The viscometer includes a coiled capillary of electroformed nickel that hydraulically connects two reservoirs located at equal heights. Using helium gas to temporarily drive liquid from a third supply reservoir, a level difference is created between the first two reservoirs without the need to tilt or invert the viscometer. Helium gas is then used to pressurize the first two reservoirs equally. Each reservoir holds a capacitive liquid-level sensor that both measure the flow induced by gravity through the capillary more precisely than by visual observations through windows. Viscosity data for liquid oxygen were acquired in the pressure domain from 0.15 to 1.0 MPa and in the temperature domain from the normal boiling point to near the freezing point. Published viscosity data and correlations for subcooled liquid oxygen are not precise nor complete in this density regime. Accordingly, the viscosity data delivered by the viscometer of the present work are superior.     

A low-power current regulator for low-temperature thermometers

A battery-supplied current regulator for low-temperature thermometers is described. The regulator operates in the range 1–10 µA and consumes a current of 0.12 mA.__________Translated from Pribory i Tekhnika Eksperimenta, No. 2, 2005, p. 146.Original Russian Text Copyright © 2005 by Tsymbalenko.     

低温食品运输过程环境监测系统研究

针对低温食品在运输过程中因温度过高引起变质而又难于实时监测的问题,运用RFID、WSN、GPS和GPRS技术,设计了由智能节点、数据采集端、RFID标签、监控管理平台和移动客户端组成的低温食品运输过程环境监测系统,着重设计了智能节点和数据采集端的硬件结构及其软件工作流程,并给出了监控管理平台和移动客户端的功能,研制了系统实验装置,对低温食品冷藏车运输过程中车厢内温、湿度和车辆位置信息进行实时监测,一旦监测到温、湿度异常能马上进行短信报警,从而确保食品的质量安全。实验测试结果表明,系统能获取低温食品运输过程中的温、湿度和地理位置信息,并将数据存储到服务器的数据库中,当监测到温度阈值时,及时地进行短信报警,能满足低温食品运输过程环境监测的要求。     

Improved system for the automatic calibration of standard resistors in the meg-ohm range

An automated measuring system has been developed to improve the calibration of high value standard resistors in the meg-ohm range at the National Institute for Standards (NIS), Egypt. This system is suitable for the calibration of the standard resistors from 100 kΩ to 100 MΩ using the DMM-based method by the substitution technique where the unknown resistor and the standard resistor are indirectly compared in the same position using a dummy resistor as a short-term reference standard. The system operation is automatically controlled by using a Lab VIEW program which is especially developed for this purpose. The uncertainty for the high value standard resistors measurement of this system is estimated. The performance of this system is also evaluated by comparing the measurement results obtained from this technique with those obtained by the direct comparison DMM-based method. It is found that the measurement uncertainty of with this method spans from 4.1 × 10⁻⁶ to 27 × 10⁻⁶, while it spans from 40 × 10⁻⁶ to 110 × 10⁻⁶ for the direct comparison method. The relative differences of the deviation from nominal values of the working standards resistors measured by the two methods are found to be within their expanded uncertainties.     

Apparatus for low-temperature inert atmosphere chemical reactions

An apparatus for carrying out chemical reactions at low temperature is presented. The apparatus is fully automatic and allows for large scale preparations.     

A computer-aided setup for measurements of the relative resistance differences of super-precision resistors

The results of investigations on the creation of a setup for measuring relative resistance differences with an rms deviation of 3×10^?8 are described. The measuring circuit, conversion function, analysis of error structure, requirements for assemblies and units of setup, and results of experimental studies confirming the possibility of obtaining readouts with an rms deviation of 5×10^?8 in the range of 100 Ω-1 kΩ and 3×10^?8 in the range of 1–10 kΩ are presented.     

基于伏-安法测量不同直流标准电阻器的电流依赖性参数

电流依赖性参数和电阻值的稳定性对直流标准电阻器的准确测量是非常重要的。本文利用伏-安法来测量四种不同标准电阻器的电流依赖性参数,并获得了不同电流下它们的电阻值稳定性。研究表明, CDC 与电流值、测量时间及电阻类型有很大关系。     

High precision lapping for polygonal holes

Lapping has been used as a finishing method to improve the roundness of shafts and holes. This paper introduces two methods for the finishing of polygonal holes whose shapes are ellipsoidal, three-lobed, four-lobed, and so on. One method is the “regular polygonal lap” in which the amplitude of the desired Fourier component of the out-of-roundness is kept constant and the other components are decreased. The other is the “tripod lap,” which can increase the amplitude of any Fourier component using special types of lapping tools produced by applying the “tripod roundness measuring method.” Based on a theoretical analysis, this study shows that any component of the out-of-roundness can be increased by using the new tripod lap method.     

Discrete liquid-helium level-meter sensors based on TVO carbon resistors

It is shown that for discrete liquid-helium level-meter sensors, based on TVO resistors with a rated power of 0.125 W and rated resistance value of 1 kΩ, one can attain a helium-level measurement error of ±0.5 mm for the horizontal TVO resistor disposition and ±2 mm for the vertical one.     

A specimen holder for low-temperature scanning electron microscopy

A miniature vise built into a copper stub is described that holds bulk, pre-frozen, hydrated biological specimens during examination under the electron beam of the scanning electron microscope.     

低温焦油的合理开发利用

对低温焦油的研究和低温焦油的生产证明，由于低温焦油沥青易发生聚合反应，可用作生产粘结性强的耐火材料粘结剂，文中介绍了低温焦油的生产加工过程低温焦油的性质和发展前景。     

大型低温液体贮罐技术方案分析

介绍了空分行业贮罐的几种类型及相关技术，并对几种方案进行了对比，使行业对这种技术有一个总体认识。     

提高自动测试系统测量精度的方法

测量精度是自动测试系统（ATS）的重要性能指标。通过系统分析典型测量通道的特性,指出了影响测量精度的因素,并给出了提高ATS测量精度的有效方法。这些方法对高性能ATS系统的组建极具参考价值。