低温锗电阻温度计温度─电阻特性曲线拟合

锗电阻温度计是低温温度测量的常用温度计之一。文中的主要内容是通过选用正确的温度电阻特性经验公式 ,将离散的锗电阻温度计实验数据点拟合成连续的数学函数曲线 ,以便在温度测量中可借助于计算机直接显示温度值。同时文章还对该特性拟合曲线的误差进行了分析     

渗碳玻璃低温温度计在液氦温度下磁致电阻的研究

渗碳玻璃低温电阻温度计具有碳膜电阻低温温度计灵敏度高、制作简单、电阻与温度呈单调变化的关系等优点,而没有碳膜电阻低温温度计重复性差,不能经受热循环的缺点,是一种比较优良的低温测温器件.国外已有商品出售. 我们研制了这种低温温度计[1],虽然结构还不够完善,经过多次测试,在液氦沸点温度测温的重复性在±5毫度以内.为了考查这种温度计在强磁场下的使用情况,我们进行了磁阻实验。 一、实验过程 在本实验中所采用的渗碳玻璃温度计是No 520,605,905,904.其中 No 520是标定过、并进行过He4沸点复现性实验的[1].它们是按下面叙述的方法…     

铜电阻温度计研究

由于高温氧化物超导体的发现[1],国内有不少实验室投入了这一工作.许多实验室都要进行液氮温区的测量,需要灵敏度高、重复性好、精度高的温度敏感元件.本文给出用商用漆包线制成的铜电阻温度计的性能,指出它的优缺点,并计算了铜电阻温度计的经验公式. 由于铜在温度较高时容易氧化,又由于它的德拜温度比铂要高,所以铜电阻温度计的使用温区要比铂电阻温度计窄.另外,铜电阻温度计的重复性为25mK[2],比铂电阻温度计要差一些.但是制作铂电阻温度计的工艺是相当考究的[3],铂丝要提纯,绕好后要进行严格的热处理,引线的设计也很特殊,以保证温度变化…     

一种宽温区实用型铑铁电阻温度计的性能研究

一种新型结构的四引线金属壳线绕铑铁电阻温度计已经研制成功，这种温度计具有尺寸小、使用温区宽的特点，同一批温度计具有较好的互换性。本介绍了这种温度计的结构、Ｒ－Ｔ特性、自然效应、稳定性和互换性，讨论了少数点标定和内插方法。     

基于G-M低温制冷机的低温温度计标定系统

设计和搭建了一套5.2—300K温区的温度计标定系统,以G-M制冷机为冷源,进口已标定温度计为定标源,对Cernox负温度系数温度计、硅二极管温度计、PT100铂电阻温度计等进行了标定,获得了其温度特性曲线并进行对比,分析了标定误差,发现该系统具有较高的标定精度,所标定的温度计在其有效温区内能达到±15mK以内的不确定度,与定标源温度计处于同等量级。     

低温温度计标定装置的研制

国家大科学工程 HT- 7U托卡马克 (Tokamak)是一个全超导核聚变实验装置。装置主机由1 6个纵场 (TF)超导线圈和 1 2个极向场 (PF)超导线圈组成 ,分别采用 4.2 K和 3 .8K超临界氦迫流冷却。选用新型低温温度计 Cernox测量超导线圈系统的温度。文中介绍低温温度计标定装置的研制和温度计 Cernox的标定结果。     

内预冷顺磁盐绝热去磁装置和国产RS-11型实芯碳电阻的极低温电阻特性

本文描述了一套内预冷顺磁盐绝热去磁装置,达到的最低温度为65mK,从136mK升温到156mK的时间为3小时,平均升温速度为7mK/小时。用这套装置测量了国产RS-11型实芯碳电阻的极低温电阻-温度特性,结果表明,不同室温名义阻值的RS-11型碳电阻可作为不同极低温温区的电阻温度计使用。     

在低温和强磁场下使用的热敏电阻温度计

本文报道了用Co-Ni-Ba-O_2合成的氧化物半导体材料制成的热敏电阻温度计。使用温区为2.8—100K,电阻从几十千欧姆光滑地变化到几十欧姆。相对灵敏度[—dR/dT×1/R]从4.2 K的60％/K左右变化到100 K的1.5％/K左右,达到了实用要求。此温度计的特点是可在强磁场下使用,在4.2 K、7T情况下,磁阻引起的温度变化为1.5～2.0％。温度计的磁阻变化可套用经验公式100×△R/R=c_1H~2/(1+c_2H~2)×T~(-1.5)。当温度不变时(T=4.2K),磁场引起的电阻变化与此公式相符。当磁场不变,磁阻随温度的升高而减小。     

用非平衡电桥法设计和组装电子数字温度计

巧用惠斯通电桥改装成非平衡电桥,使用碳膜电阻或铂电阻作感温元件,数字电压表作为显示器,组装成电子数字温度计。     

内预冷顺磁盐绝热去磁装置和国产RS-11型实芯碳电阻的极低温电阻特性

本文描述了一套内预冷顺磁盐绝热去磁装置,达到的最低温度为65mK,从136mK升温到156mK的时间为3小时,平均升温速度为7mK/小时。用这套装置测量了国产RS-11型实芯碳电阻的极低温电阻-温度特性,结果表明,不同室温名义阻值的RS-11型碳电阻可作为不同极低温温区的电阻温度计使用。     

测量爆炸火焰真温的多光谱温度计的研制——现场实验与测量精度分析

研制了可用于大型爆炸现场的、 测量爆炸火焰真温的多光谱温度计(量程为800~3 500 ℃,波长范围为0.6~1.1 μm)。测量原理进一步改进,加入亮温逼近法解决了二次测量法初值选取困难的问题,并应用此高温计在空旷场地对3 kg TNT炸药爆炸的全过程进行测量。通过实验结果的分析可知,此高温计可以测量爆炸火焰真温变化全过程,对波阵面瞬时温度与燃烧火球温度的测量均具有很好的效果。同时,分析了影响此高温计测量精度的各个因素,得出目前制约多光谱高温计测量精度提高的主要因素仍然为真温算法及标定方法的误差,这为今后研制高精度高温计明确了方向。     

A New Generation of Primary Luminescent Thermometers Based on Silicon Nanoparticles and Operating in Different Media

Luminescence nanothermometry is nowadays a highly‐dynamic research topic that is being driven by the challenging demands arising from dissimilar areas such as microelectronics, microfluidics and nanomedicine. Although the technique is rapidly evolving from the initial breakthrough to real applications, there are still major challenges regarding the conciliation of nanometric probes with the high sensitivity and predictability of the thermal response of the system. In the past five years, luminescent thermometers operating at the nanoscale, where the conventional methods are ineffective, have emerged as a very active field of research. Luminescent silicon nanoparticles (SiNPs) are a promising choice for nanothermometry, combining the Si biocompatibility with the compatibility with the current microelectronic technology. Here, the thermal dependence of the emission peak position of SiNPs, used as the thermometric parameter, is well‐described by the Varshni's law, enabling the development of a self‐calibrated nanothermometer with a calibration curve predicted by a well‐stablished state equation, avoiding new calibration procedures whenever the thermometer operates in different media. For the first time, temperature sensing using SiNPs‐based luminescent thermometers in different media without the need of new calibration procedures is demonstrated. The thermometer reveals reversibility and repeatability higher than 99.98%, and a maximum relative sensitivity of 0.04% K^?1.     

Application for optical thermometers calibration based on virtual instruments

In this paper we present a new developed application for calibration of optical thermometers which is implemented in the Serbian Metrology Institute. The method for calibration of optical thermometer–pyrometer is based on measuring blackbody temperature via thermocouple standards and measuring voltage on pyrometer in temperature range from 550 to 1650 °C. The objective is to precisely determinate calibration curve of pyrometer—transfer function. The metrology traceability was realized through thermocouples standard which has traceability to the international standard. A developed application has a role to control and supervise calibration process. Based on virtual instruments (VI), application offers monitoring measurement parameters in real time on three charts. The main advantage of the developed VI application is reduction of measurement uncertainty of type A by increased accuracy with multi—temperature measurement up to 3 thermocouples on temperature equilibrium in the measurement system and automatic data processing by converting voltage to temperature, calculating the mean value and standard deviation of the mean value. Advantage is also reflected in permanent data logging while application is running and low cost and user friendly interface One of the goals is to improve quality of metrological services through this application and support the establishment of a traceability chain to SI.     

在选绝对温标为标准后所引起的一些实际问题

本文对在给定水的三相点的绝对温度以一定的数值(例如T₃=273.1700),同时以绝对温标代替摄氏温标以后所引起的一些实际问题作了讨论。这些问题包括气体温度计的改正及电阻温度计和温差电偶温度计的规定。本文指出,在以绝对温标为标准以后,寻求冰点的绝对温度与对气体温度计的改正两种工作统一起来了。又指出,在以绝对温标为标准以后,绝对温度测量的精确度将大大提高。     

3He melting curve thermometry in a nuclear polarization experiment

Temperature measurement and control are important in brute force polarization experiments. We discuss the installation and use of³He melting curve thermometers in a crystat used to polarize a TiH₂ target. Comparison is made between the melting curve thermometers and the⁶⁰CoCo nuclear orientation thermometer, which is often used in such experiments. The melting curve thermometers provide increased temperature resolution and sensitivity, and were used in a feedback heating system to control temperature to ±5.5 μK at 16.5 mK. The³He melting curve and the⁶⁰CoCo temperature scales are found to agree within 2% at 15 mK. The present status of the melting curve scale and the effect of a magnetic field on melting curve thermometry are also discussed.     

Quartz Crystal Temperature Sensor for MAS NMR

Quartz crystal temperature sensors (QCTS) were tested for the first time as wireless thermometers in NMR MAS rotors utilizing the NMR RF technique itself for exiting and receiving electro-mechanical quartz resonances. This new tool in MAS NMR has a high sensitivity, linearity, and precision. When compared to the frequently used calibration of the variable temperature in the NMR system by a solid state NMR chemical shift thermometer (CST), such as lead nitrate, QCTS shows a number of advantages. It is an inert thermometer in close contact with solid samples operating parallel to the NMR experiment. QCTS can be manufactured for any frequency to be near a NMR frequency of interest (typically 1 to 2 MHz below or above). Due to the strong response of the crystal, signal detection is possible without changing the tuning of the MAS probe. The NMR signal is not influenced due to the relative sharp crystal resonance, restricted excitation by finite pulses, high probeQvalues, and commonly used audio filters. The quadratic dependence of the temperature increase on spinning speed is the same for the QCTS and for the CST lead nitrate and is discussed in terms of frictional heat in accordance with the literature about lead nitrate and with the results of a simple rotor speed jump experiment with differently radial located lead nitrate in the rotor.     

Low temperature thermometry, 1 to 30 K

The current interest and activity in thermometry between 4 and 20 K is due primarily to the development and subsequent commercial availability of 4-terminal germanium resistors as reproducible and sensitive thermometers. These have assumed the same role below 20 K as platinum resistance thermometers have above 20 K. Thermometric techniques in this low temperature region have evolved from insensitive alloy thermometers (such as constantan) to the use of high sensitivity (but sometimes irreproducible) carbon radio resistors to the introduction of the first suitably-doped germanium resistance thermometers by Kunzler and his co-workers at the Bell Telephone Laboratories.¹ Thermometers of this type now are manufactured by several different concerns and they are used routinely at temperatures from 0.1 to 40 or 50 K with mK sensitivity and reproducibility. These thermometers have brought about a considerable rethinking and simplification of cryogenic techniques; and, in many instances, they are used from 1 to 20 K (or higher) with calibrations which are certified by or traceable to Standards Laboratory scales, with little or no provision made for checks of the calibration by the user.     

Temperature-Dependent Solid-State 119Sn- MAS NMR of Nd2Sn2O7, Sm2Sn2O7, and Y1.8Sm0.2Sn2O7. Three Sensitive Chemical-Shift Thermometers

The ¹¹⁹Sn MAS NMR resonances of the paramagnetic stannates Ln₂Sn₂O₇ (Ln = Nd, Sm, and Y_1.8Sm_0.2) have been found to be extremely sensitive to temperature, the isotropic resonances varying, at room temperature, by 14 and 1.1 ppm K^−l for Nd₂Sn₂O₇ and Sm₂Sn₂O₇, respectively. This sensitivity has been exploited to develop three chemical-shift thermometers with reciprocal dependences on temperature. Sm₂Sn₂O₇ is suitable for temperature calibration of standard MAS probes and the solid solution Y_1.8Sm_0.2Sn₂O₇ is a shift thermometer with an internal reference. Nd₂Sn₂O₇ is proposed as a high-temperature shift thermometer. These thermometers were used to determine the changes in sample temperature, in a Bruker 7 mm double-bearing probe, as the MAS speed was varied. A change of 8.5 K was observed on increasing the MAS speed from 1 to 5 kHz. The short relaxation times of the ¹¹⁹Sn nuclei enabled short recycle times to be used, and spectra of Sm₂Sn₂O₇ could be obtained in seconds.