Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation最新文献_第2页

Heated air adiabatic saturation psychrometer 热空气绝热饱和湿度计

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1971-04-01 DOI: 10.6028/JRES.075C.008

L. Greenspan

{"title":"Heated air adiabatic saturation psychrometer","authors":"L. Greenspan","doi":"10.6028/JRES.075C.008","DOIUrl":"https://doi.org/10.6028/JRES.075C.008","url":null,"abstract":"A portable self·contained heated·air adiabatic saturation psychrometer intended as a field a nd laboratory instrument has been developed and constructed. The instrument measures the humidity of air in the range from 0 to 50 grams of water vapor per kilogram of dry air over an ambient temperature range of -5 to 40°C. It samples a test gas at the rate of 4 liters per minute. The psychrometer was compared with the NBS pressure humidity generator over the mixing ratio range of 2.5 to 19 grams of water per kilogram ot dry air (equivalent to a dew-point range of -5.4 to 24°C at atmospheric pressure) . The mixing ratio indicated by the psychrometer was higher than that produced by the generator by 0.025 g/kg + 0.24 percent of the reading with a standard deviation of 0.024 g/ kg; tha t is, it was hi gher by 1.24 percent to 0.37 percent of the readin g as the measured mixing ratio increased from 2.5 to 19 g/kg. In equivalent terms of dew point, the psychrometer read ing was higher by 0.16 deg C to 0.06 deg C as the measured dew point increased from 5.4 to 24.0 0C. The results are approximately those which would be expected based on an analysis of estimated errors in individual measurements.","PeriodicalId":367668,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1971-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124089222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

An improved method for microwave power calibration, with application to the evaluation of connectors 一种改进的微波功率校准方法，并应用于连接器的评定

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1971-04-01 DOI: 10.6028/JRES.075C.011

G. Engen

{"title":"An improved method for microwave power calibration, with application to the evaluation of connectors","authors":"G. Engen","doi":"10.6028/JRES.075C.011","DOIUrl":"https://doi.org/10.6028/JRES.075C.011","url":null,"abstract":"In the procedures for microwave power calibration, which are well documented, the subject of mismatch errors (or corrections) plays a major role. In particular, the evaluation of mismatch corrections requires the measurement of complex r eflection coefficients; and the accuracy of this measurement is limited , in part, by connector imperfections. The applica tion of recently developed \"power equation\" methods to th is problem provides both a simplified determ ination of the mismatch correction (Mgm) and improved accuracy. In particular, the intermed iate step of measuring the reflection coefficients is eliminated, and the precision connector requirement is greatly relaxed. If this new method were adopted at each level of the usual calibrat ion hierarchy, the accuracy of disseminating measuremen ts re ferenced to the primary standards at NBS would be greatly improved. T he accuracy potential was demonstrated in a series of experiments involving the Type N, GPC-7, a nd waveguide flan ge connectors. The outcome of this experi ment al evaluation, in whi ch the \"ord inary\" Type N performed on a par with GPC-7, rai ses some rather serious questions relative to current trends in connector development.","PeriodicalId":367668,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1971-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127219606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Computation of the temperature distribution in cylindrical high-pressure furnaces 圆柱形高压炉内温度分布的计算

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1971-04-01 DOI: 10.6028/JRES.075C.009

M. Waxman, J. R. Hastings

引用次数: 1

A time-shared computer system for diffractometer control 用于衍射仪控制的分时计算机系统

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1970-07-01 DOI: 10.6028/JRES.074C.011

H. Alperin, E. Prince

引用次数: 5

Bolovac application for HF and microwave power measurement and standardization Bolovac应用于高频和微波功率的测量和标准化

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1970-07-01 DOI: 10.6028/JRES.074C.015

M. C. Selby

引用次数: 2

Techniques for comparing four-terminal-pair admittance standards 比较四端对导纳标准的技术

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1970-07-01 DOI: 10.6028/JRES.074C.008

R. D. Cutkosky

引用次数: 46

Some applications for series impedance elements in radio frequency immittance measurements 串联阻抗元件在射频阻抗测量中的一些应用

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1970-07-01 DOI: 10.6028/JRES.074C.009

L. Huntley

引用次数: 0

"Connector-pair" techniques for the accurate measurement of two-terminal low-value capacitances 用于精确测量双端低值电容的“连接器对”技术

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1970-07-01 DOI: 10.6028/JRES.074C.013

A. Millea

引用次数: 0

The use of dew-point temperature in humidity calculations 在湿度计算中使用露点温度

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1970-07-01 DOI: 10.6028/JRES.074C.014

L. Wood

引用次数: 31

A pulse heating method for the measurement of melting point of electrical conductors (thin wires) above 2000 K 一种测量2000 K以上电导体(细导线)熔点的脉冲加热方法

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1970-07-01 DOI: 10.6028/JRES.074C.010

A. Cezairliyan

{"title":"A pulse heating method for the measurement of melting point of electrical conductors (thin wires) above 2000 K","authors":"A. Cezairliyan","doi":"10.6028/JRES.074C.010","DOIUrl":"https://doi.org/10.6028/JRES.074C.010","url":null,"abstract":"In general, melting points of subs tances are determided using quasi steady-state techniques, where the specime n is ei ther heated or cooled very slowly until a phase cha nge is detec ted. These methods present difficulties at high temperatures (above 2000 K) due to increased heat transfer, che mical reactions , evaporation , loss of mechanical strength , e tc. In ord er to overcome most of these diffic ulties experiments may be performed in short tim es by heating the specimen rapidly to its melting point. A technique utilizing this approach was described in the li terature [l].1 The specime n was of tubular form (100 mm long, 6.4 mm outside diameter , 0.5 mm wall thickness) with a small hole in the wall at the middle of the specime n. The cylindrical specimen approximated blackbody conditions for optical (pyrometric) temperature measurements. The specimen was heated from room temperature to its melting point in less than one second by the passage of a high current (2000 A) through it. The maximum te mperature attained was the melting point. The melting point obtained by this me thod was reproducible within 1 K (standard deviation of the mean). The tubular specimen had to be des troyed during each determination. The cost and difficulty of fabri cati ng specimens used in the above s tudy make it unsuitable for ge neral use. The objective of thi s note is to describe a highspeed method of measuring melting point of electrical conductors (with melting points above 2000 K) where the specimens are in the form of thin wires. The method is based on de tecting melting of a specimen which is wound around a tube as the latter is heated rapidly in vacuum. The limitation of the measureme nts to te mperatures above approximately 2000 K is im-","PeriodicalId":367668,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1970-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127347160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0