Journal of research of the National Bureau of Standards. Section A, Physics and chemistry最新文献

{"title":"A Method for Determining the Elastic Constants of a Cubic Crystal from Velocity Measurements in a Single Arbitrary Direction; Application to SrTiO3.","authors":"J. B. Wachtman, M. Wheat, S. Marzullo","doi":"10.6028/JRES.067A.018","DOIUrl":"https://doi.org/10.6028/JRES.067A.018","url":null,"abstract":"Three independent velocities of sound can be measured along any direction of propagation in a cubic crystal except the [100] and [111] directions. These three velocities suffice to determine the three elastic constants and for the [110] direction, the calculation of these constants is easy. For all other directions, the calculation is more difficult; the only existing method appears to be a perturbation technique developed by Neighbours. The present paper presents a method using exact equations and an iterative procedure to solve these equations and to calculate both the elastic constants and their standard deviations from the sound velocities and their standard deviations. The method is illustrated with new data on SrTiO3 which give c11=3.156±0.027, c12=1.027±0.027, c44= 1.215±0.006×1012 dynes/cm2 at 25 °C. The importance of including covariance terms in calculations of the standard deviations is emphasized.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1963-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75883973","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}

{"title":"Effect of Pressure and Temperature on the Refractive Indices of Benzene, Carbon Tetrachloride, and Water.","authors":"R. Waxler, C. Weir","doi":"10.6028/JRES.067A.016","DOIUrl":"https://doi.org/10.6028/JRES.067A.016","url":null,"abstract":"An interferometer for measuring change in index of refraction with pressure is described. Absolute indices of refraction are reported to five decimals for benzene, carbon tetrachloride, and water at pressures as high as 1100 bars over a small temperature range. The results of replicate measurements agree to within ±0.0001. Various equations relating index and specific volume show systematic deviations in all cases. At constant specific volume, the index of carbon tetrachloride increases with increasing temperature, while the index of water decreases with increasing temperature. The refractive index of benzene shows no effect due solely to temperature within the experimental error. Possible explanations for this behavior are discussed.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1963-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80655342","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}

{"title":"Quantitative Metallography With a Digital Computer: Application to a Nb-Sn Superconducting Wire.","authors":"G. Moore, L. Wyman","doi":"10.6028/JRES.067A.013","DOIUrl":"https://doi.org/10.6028/JRES.067A.013","url":null,"abstract":"Accurate quantitative data pertinent to the structure of solid materials at the micro size level, which are difficult or prohibitive to obtain by traditional manual measurements, are now obtained directly by a digital computer which uses a photomicrograph as the information input. The history of picture interpretation experiments at the National Bureau of Standards is reviewed. The fundamental computer operations are illustrated, together with a description of 24 image processing routines now functional at a practical level. A micrograph of a specimen of Nb-Sn superconductor wire is exhaustively analyzed. This specimen is found to contain approximately 70 percent Nb3Sn, nearly all of which is mutually interconnected. It is also found that in this specimen the mean free path in the Nb3Sn superconducting phase is only 26.5 microns. This small value results from the spongy structure of the material and numerous interruptions caused by voids and by particles of four other solid phases. The comparative importance of the several types of interruptions is measured. It is determined that small voids are the most important single cause of the short mean free path, and deduced that these voids appear to have formed mainly from the reaction during heat treatment.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1963-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73012624","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}

{"title":"Moiré Fringes Produced by a Point Projection X-ray Microscope.","authors":"S. Newman","doi":"10.6028/jres.067a.014","DOIUrl":"https://doi.org/10.6028/jres.067a.014","url":null,"abstract":"Moiré fringes produced by soft X-rays passing through crossed gratings of fine wire mesh are demonstrated. Regular systems of bands appearing superimposed on radio-micrographs of oriented cellulosic structures may also be moiré fringes. These fringes could be formed by fibrillate structures acting as crossed diffraction gratings.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1963-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77871090","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}

{"title":"Broadening of the Rotational Lines of Carbon Monoxide by HCl and by Argon.","authors":"R. J. Thibault, J. H. Jaffe, E. K. Plyler","doi":"10.6028/JRES.067A.011","DOIUrl":"https://doi.org/10.6028/JRES.067A.011","url":null,"abstract":"The present work deals with the broadening of rotational lines of the carbon monoxide 2-0 band by both argon and hydrogen chloride. A high resolution grating spectrometer with a spectral slit width of 0.07 cm-1 was used, necessitating only a small correction in observed half-width values. Sufficiently small contributions of CO self-broadening were obtained by using long pathlength cells of 12 meters for CO-argon mixture and 1 meter for CO-HCl mixture. Half-width results, which are considered accurate to within ±5 percent, are presented in the form of a table and by a graph.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1963-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82744019","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}

{"title":"Dynamic Compressibility of Poly (Vinyl Acetate) and Its Relation to Free Volume","authors":"J. McKinney, H. .. Belcher","doi":"10.6028/jres.067A.007","DOIUrl":"https://doi.org/10.6028/jres.067A.007","url":null,"abstract":"The complex bulk compliance (dynamic compressibility) of a commercial sample of poly (vinyl acetate), AYAT, was measured at frequencies from 50 to 1,000 cycles per second, temperatures from 0 to 100 °C, and static hydrostatic stresses from 0 to 981 bars (gage pressure) using an alternating hydrostatic stress generated and detected by piezoelectric transducers mounted in an essentially noncompliant cavity with dimensions small in comparison to a wavelength. The above temperature range was more than sufficient to cover the dispersion region in which an inflection in the storage compliance and a maximum in the loss compliance were observed. The data were reduced to functions of reduced variables using the WLF Equations extended to include static pressure with the “universal” WLF Constants and dT/dP = 0.020 °C/bar. The difference in limiting compliances at zero and infinite frequencies was larger than that predicted from the dT/dP shift using the free volume concept. A discussion is presented on possible processes that might contribute to an excessive value between limiting compliances.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1963-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84102650","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}

{"title":"An Investigation of the Constitution of the Mercury-Tin System1","authors":"D. F. Taylor, C. L. Burns","doi":"10.6028/jres.067A.008","DOIUrl":"https://doi.org/10.6028/jres.067A.008","url":null,"abstract":"An investigation of the constitution of the mercury-tin system was made by a combination of three techniques: differential thermal analysis; diffusion and chemical analysis; and X-ray diffraction. The mercury-silver-tin system is of interest because it is the basis of dental amalgam, the most important single dental restorative material. Information as to the constitution of these alloys is incomplete for both the ternary system and the mercury-tin binary system. This study was devoted to the investigation of the mercury-tin system as a prerequisite to a study of the ternary alloys. The results obtained by the various methods are not in complete agreement. They indicate that the system is more complex than previously reported. Additional evidence for the beta phase as reported by Prytherich was found but the composition limits and eutectoid temperature remain to be confirmed. The gamma phase composition limits were found to differ from earlier values. Corroborative data for Gayler’s delta phase and possible evidence for a previously unreported epsilon phase have been found by X-ray diffraction. The thermal analysis results indicate the possible existence of additional phases unconfirmed by other methods. A modified mercury-tin phase diagram based upon these findings is proposed.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1963-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73370066","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}

{"title":"2,3-Dimethylpentane and 2-Methylhexane as a Test Mixture for Evaluating Highly Efficient Fractionating Columns*","authors":"E. C. Kuehner","doi":"10.6028/jres.067A.002","DOIUrl":"https://doi.org/10.6028/jres.067A.002","url":null,"abstract":"A test mixture consisting of 2,3-dimethylpentane and 2-methylhexane was prepared and its relative volatility determined by a fractional distillation method. This test mixture was compared, experimentally and theoretically, with another test mixture commonly used for evaluating highly efficient fractionating columns.","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1963-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83279068","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}

{"title":"Radial Distribution Study of Vitreous Barium Borosilicate.","authors":"G J Piermarini, S Block","doi":"10.6028/jres.067A.006","DOIUrl":"10.6028/jres.067A.006","url":null,"abstract":"<p><p>An X-ray diffraction study of a barium borosilicate glass consisting of 24 mole percent barium oxide, 40 mole percent boric oxide, and 36 mole percent silicon dioxide has been performed. Resulting atomic radial distribution functions give the following average interatomic distances: Si-O, 1.6 A; Ba-O, 2.8 A; Ba-Ba, 4.7 A; and Ba-Ba, 6.8 A. From the 4.7 A Ba-Ba separation a Ba-O-Ba bond angle of about 115° has been calculated. The observed average barium separations are in partial agreement with that predicted by Levin and Block on the basis of a structural interpretation of immiscibility data. A proposed coordination change by Levin and Block for the barium atoms in the system has been confirmed, but the details of the coordination change mechanism have not. Combining the results of the radial distribution study and immiscibility data on the barium borosilicate modifier-rich liquid at maximum barium oxide content has indicated that approximately 16.75 mole percent barium oxide is involved in the 4.7 A separation and 8.25 mole percent is associated with the 6.8 A separation. A mechanism which allows the composition of the modifier-rich liquids in the ternary system to be calculated has been presented. The calculated composition has been found to agree well with the experimental value.</p>","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1963-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5324957/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79717811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat of Formation of Calcium Aluminate Monosulfate at 25 °C.","authors":"H A Berman, E S Newman","doi":"10.6028/jres.067A.001","DOIUrl":"10.6028/jres.067A.001","url":null,"abstract":"<p><p>The heat of formation of calcium aluminate monosulfate, 3CaO·Al₂O₃·CaSO₄·12H₂O, at 25 °C, and of less completely hydrated samples of the same compound, was determined by the heat-of-solution method, with 2<i>N</i> HCl as the solvent, and 3CaO·Al₂O₃·6H₂O(c) and CaSO₄·2H₂O(c), as the reactants. The results were as follows: Δ<i>H, kj/mole</i>Δ<i>H, kcal/mole</i>3CaO·Al₂O₃·CaSO₄·12H₂O(c) Heat of formation  from elements, <math><mrow><mi>Δ</mi> <msubsup><mi>H</mi> <mi>f</mi> <mo>°</mo></msubsup> </mrow> </math> -2100  from reactants and H₂O(1)-15.0 Heat of solution in 2<i>N</i> HCl- 495.7- 118.5 Change of heat of solution  with H₂O content at 12H₂O, per mole H₂O <math> <mrow> <mfrac><mrow><mi>d</mi> <mrow><mo>(</mo> <mrow><mi>Δ</mi> <mi>H</mi></mrow> <mo>)</mo></mrow> </mrow> <mrow><mi>d</mi> <mi>n</mi></mrow> </mfrac> </mrow> </math> 1.93 The heat of the reaction (Δ<i>H</i>) <dispformula> <math> <mtable> <mtr><mtd><mn>3</mn> <mi>CaO</mi> <mo>⋅</mo> <msub><mi>Al</mi> <mn>2</mn></msub> <msub><mi>O</mi> <mn>3</mn></msub> <mo>⋅</mo> <msub><mi>CaSO</mi> <mn>4</mn></msub> <mo>⋅</mo> <mn>12</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi> <mrow><mo>(</mo> <mi>c</mi> <mo>)</mo></mrow> <mo>+</mo> <mn>2</mn> <mrow><mo>(</mo> <mrow> <msub><mrow><mi>CaSO</mi></mrow> <mn>4</mn></msub> <mo>⋅</mo> <mn>2</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi></mrow> <mo>)</mo></mrow> <mrow><mo>(</mo> <mi>c</mi> <mo>)</mo></mrow> <mo>+</mo> <mn>15</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi> <mrow><mo>(</mo> <mi>l</mi> <mo>)</mo></mrow> <mo>→</mo></mtd> </mtr> <mtr><mtd><mn>3</mn> <mi>CaO</mi> <mo>⋅</mo> <msub><mi>Al</mi> <mn>2</mn></msub> <msub><mi>O</mi> <mn>3</mn></msub> <mo>⋅</mo> <mn>3</mn> <msub><mi>CaSO</mi> <mn>4</mn></msub> <mo>⋅</mo> <mn>31</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi> <mrow><mo>(</mo> <mi>c</mi> <mo>)</mo></mrow> </mtd> </mtr> </mtable> </math> </dispformula> is -134.4 kj/mole or -32.1 kcal/mole. The heat of the reaction (Δ<i>H</i>) <dispformula> <math> <mtable> <mtr><mtd><mn>3</mn> <mi>CaO</mi> <mo>⋅</mo> <msub><mi>Al</mi> <mn>2</mn></msub> <msub><mi>O</mi> <mn>3</mn></msub> <mo>⋅</mo> <msub><mi>CaSO</mi> <mn>4</mn></msub> <mo>⋅</mo> <mn>12</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi> <mrow><mo>(</mo> <mi>c</mi> <mo>)</mo></mrow> <mo>+</mo> <mn>2</mn> <mrow><mo>(</mo> <mrow> <msub><mrow><mi>CaSO</mi></mrow> <mn>4</mn></msub> <mo>⋅</mo> <mn>2</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi></mrow> <mo>)</mo></mrow> <mrow><mo>(</mo> <mi>c</mi> <mo>)</mo></mrow> <mo>+</mo> <mn>16</mn> <msub><mi>H</mi> <mn>2</mn></msub> <mi>O</mi> <mrow><mo>(</mo> <mi>l</mi> <mo>)</mo></mrow> <mo>→</mo></mtd> </mtr> <mtr><mtd><mn>3</mn> <mi>CaO</mi> <mo>⋅</mo> <msub><mi>Al</mi> <mn>2</mn></msub> <msub><mi>O</mi> <mn>3</mn></msub> <mo>⋅</mo> <mn>3</mn> <m","PeriodicalId":94340,"journal":{"name":"Journal of research of the National Bureau of Standards. Section A, Physics and chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1963-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5324954/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83361580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}