Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation最新文献_第10页

A self-calibrating instrument for measuring conductance at radio frequencies 一种在无线电频率上测量电导的自校准仪器

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1965-04-01 DOI: 10.6028/JRES.069C.015

L. Huntley

{"title":"A self-calibrating instrument for measuring conductance at radio frequencies","authors":"L. Huntley","doi":"10.6028/JRES.069C.015","DOIUrl":"https://doi.org/10.6028/JRES.069C.015","url":null,"abstract":"Accuracies obtainable in measuring resistance (co nductance) at radio frequencies have lagged behind those obtainable in measuring reactance (s usceptancc), bccause frequencyd ependent changes in the values of r esistors ar c not as well known as are such changes in capacitors, and because no satisfactory method has existed for comparing resistors to capacitors at radio frequencies. An instrum ent based 011 the twin T null circuit can be made self-calibrating at a given frequency, allowing conductances in the proper range to be measured directly in terms of a change in capacitance, without any need for acc urate knowledge of t he values of the circuit elements. Analysis of a practical circuit shows t hat such an instrum ent is potentially capable of measuring conductance to within a few parts in 106 at frequencies below abo ut 15 MHz, and t hat accuracies actually obtained will be limi ted only by the accuracy to which changes in effective capacitance are known. Conductances between 0.01 and 0.0001 mho were measured at 107 radians/sec with an estimated erro l' of 0.05 percent, which is the errol' associated with the measurement of changes in effective capacitance at that freq uency.","PeriodicalId":367668,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1965-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131116494","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: 7

Temperatures of thermocouple reference junctions in an ice bath 冰浴中热电偶参考结点的温度

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1965-04-01 DOI: 10.6028/JRES.069C.013

F. R. Caldwell

引用次数: 4

Exact inductance equations for rectangular conductors with applications to more complicated geometries 矩形导体的精确电感方程及其在更复杂几何中的应用

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1965-04-01 DOI: 10.6028/JRES.069C.016

C. Hoer, C. Love

引用次数: 303

Steady-state heat conduction in an exposed exterior column of rectangular cross section 矩形截面外露柱的稳态热传导

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1965-04-01 DOI: 10.6028/JRES.069C.018

B. Peavy

引用次数: 2

Common volume of two intersecting cylinders 两个相交圆柱体的公共体积

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1965-04-01 DOI: 10.6028/JRES.069C.017

J. Hubbell

引用次数: 11

Superimposed birefractory plates 叠合双耐火板

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1965-04-01 DOI: 10.6028/JRES.069C.014

L. Adams, R. M. Waxler

引用次数: 2

Reference tables for the Platinel II thermocouple Platinel II热电偶参考表

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1964-10-01 DOI: 10.6028/JRES.068C.029

L. O. Olsen, P. Freeze

引用次数: 1

Review of methods for the excitation of atomic and ionic spectra by means of high-frequency discharges and sliding sparks 高频放电和滑动火花激发原子和离子光谱方法综述

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1964-10-01 DOI: 10.6028/JRES.068C.024

L. Minnhagen

{"title":"Review of methods for the excitation of atomic and ionic spectra by means of high-frequency discharges and sliding sparks","authors":"L. Minnhagen","doi":"10.6028/JRES.068C.024","DOIUrl":"https://doi.org/10.6028/JRES.068C.024","url":null,"abstract":"The development o[ appropriate sources [or the excitation of t1.to mic a nd ionic spectra is a fund amental task in atomic spectroscopy. The demands on t he sources are, generally speaking, t hat tJl ey should produce t he actual spectr a with a higll degree or complete ness, wit h t he best possible lin e quality, and, as far as possible, free from impurities. Further , t he sources shouldm.ake it possible to decide from whicll ionization stage the spectrum lin es originate. The required sharpn ess of the lin es depend on t he char acter of t he investigation . Obviously t he greatest pos ible reduction o[ the line widthcaused by Doppler effect, collisions, Stark effect etc.is necessary [or the determination of highly aCCUntte wavelengths and for t he in vestigat ion of hyperfine structure by means o[ highresolution spectroscopy, while the demands [or sharpness are much less in some kinds of straightforward a nalytical work . It is so metimes an fLdvan tage to have excitatiOll co ndi tions which give observable Stark-effect broadenings, since the broadenings depend on the quantum properties and energies of the levels in -0 1 ved and t hus facilitate the analysis. Analogously, ligh t sources giving rise to strong self-reversal are inappropriate in some investigations, whereas they may be advantageous in the analysis of a spectrum. In the present review t wo groups of sources useful for the production of spectr a of low and medium ionization stages will be treated, nfLmely highfrequency excitation and the sliding spade","PeriodicalId":367668,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1964-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125547483","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

Heat flow in a right circular cylinder with arbitrary temperature boundary conditions - applications to the determination of thermal conductivity 具有任意温度边界条件的右圆柱内的热流。在热导率测定中的应用

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1964-10-01 DOI: 10.6028/JRES.068C.021

D. Flynn

引用次数: 1

A Pienkowsky-type calibration scheme for 5211S1 weight series using two knife-edge direct-reading balances 5211S1重量系列的pienkowsky型校准方案，使用两个刀口直读天平

Journal of Research of the National Bureau of Standards, Section C: Engineering and Instrumentation Pub Date : 1964-10-01 DOI: 10.6028/JRES.068C.028

H. Peiser

引用次数: 2