Pub Date : 1969-02-01DOI: 10.1088/0022-3735/2/2/306
J Langelaar, G A de Vries, D Bebelaar
The construction of a sensitive spectrophosphofluorimeter is reported. The sensitivity of the detection system has been increased by the use of a cooled selected photomultiplier and a lock-in amplifier or time averaging computer. Essential accessories are the electronic ratio system and the xenon arc stabilization device with a stabilization factor up to 103. Measurements of decay times greater than 0·1 ms for weak signals are possible with this instrument.
{"title":"Sensitivity improvements in spectrophospho-fluorimetry.","authors":"J Langelaar, G A de Vries, D Bebelaar","doi":"10.1088/0022-3735/2/2/306","DOIUrl":"https://doi.org/10.1088/0022-3735/2/2/306","url":null,"abstract":"The construction of a sensitive spectrophosphofluorimeter is reported. The sensitivity of the detection system has been increased by the use of a cooled selected photomultiplier and a lock-in amplifier or time averaging computer. Essential accessories are the electronic ratio system and the xenon arc stabilization device with a stabilization factor up to 103. Measurements of decay times greater than 0·1 ms for weak signals are possible with this instrument.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":"2 2","pages":"149-52"},"PeriodicalIF":0.0,"publicationDate":"1969-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/2/306","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16872473","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}
Pub Date : 1969-02-01DOI: 10.1088/0022-3735/2/2/313
G. Gerrits, W. Bol
In x-ray diffraction techniques for liquids, balanced (Ross) filters can be used for obtaining an essentially monochromatic beam. This article describes how correct balancing can be tested experimentally. The method is based on the use of a strongly fluorescent solution (e.g. for Mo Ka radiation a solution containing Y). The filters are then balanced until the fluorescent radiation is equally absorbed by both filters. The measurements are carried out under conditions identical to those existing in the actual experiments.
{"title":"Balancing Ross filters in x-ray diffraction of liquids","authors":"G. Gerrits, W. Bol","doi":"10.1088/0022-3735/2/2/313","DOIUrl":"https://doi.org/10.1088/0022-3735/2/2/313","url":null,"abstract":"In x-ray diffraction techniques for liquids, balanced (Ross) filters can be used for obtaining an essentially monochromatic beam. This article describes how correct balancing can be tested experimentally. The method is based on the use of a strongly fluorescent solution (e.g. for Mo Ka radiation a solution containing Y). The filters are then balanced until the fluorescent radiation is equally absorbed by both filters. The measurements are carried out under conditions identical to those existing in the actual experiments.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":"62 1","pages":"175-177"},"PeriodicalIF":0.0,"publicationDate":"1969-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85784063","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}
Pub Date : 1969-02-01DOI: 10.1088/0022-3735/2/2/435
V P Lipton, A Lipton
A combined oscillator-detector is described for control of laboratory operations by programmed magnetic tape. In addition to eliminating the need to match oscillator and detector frequencies this unit has improved temperature stability, more compact circuitry and built-in controls for sensitivity and sharpness of tuning; this makes it possible to use narrow bandwidths if desired, thus increasing the number of controlling frequencies which can be used in the audio-frequency range of the tape.
{"title":"A combined oscillator-detector circuit for programmed laboratory sequencers.","authors":"V P Lipton, A Lipton","doi":"10.1088/0022-3735/2/2/435","DOIUrl":"https://doi.org/10.1088/0022-3735/2/2/435","url":null,"abstract":"A combined oscillator-detector is described for control of laboratory operations by programmed magnetic tape. In addition to eliminating the need to match oscillator and detector frequencies this unit has improved temperature stability, more compact circuitry and built-in controls for sensitivity and sharpness of tuning; this makes it possible to use narrow bandwidths if desired, thus increasing the number of controlling frequencies which can be used in the audio-frequency range of the tape.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":"2 2","pages":"219-20"},"PeriodicalIF":0.0,"publicationDate":"1969-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/2/435","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16872474","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}
Pub Date : 1969-01-01DOI: 10.1088/0022-3735/2/1/311
C E Hahn
An inexpensive method of measuring the current in an oxygen polarographic cathode electrode is described. The method entails the use of a field-effect transistor operational voltage amplifier connected as a transresistance converter, the output of which is read directly by a digital voltmeter.
{"title":"The measurement of oxygen microcathode currents by means of a field-effect transistor operational amplifier system with digital display.","authors":"C E Hahn","doi":"10.1088/0022-3735/2/1/311","DOIUrl":"https://doi.org/10.1088/0022-3735/2/1/311","url":null,"abstract":"An inexpensive method of measuring the current in an oxygen polarographic cathode electrode is described. The method entails the use of a field-effect transistor operational voltage amplifier connected as a transresistance converter, the output of which is read directly by a digital voltmeter.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":"2 1","pages":"48-50"},"PeriodicalIF":0.0,"publicationDate":"1969-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/1/311","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16871198","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}
Pub Date : 1969-01-01DOI: 10.1088/0022-3735/2/1/317
W L Gent
Differential scanning calorimetry has been used to investigate the heat of fusion (ΔHf=7·12 kcal per g mol) and true melting temperature (T0=422·4°K) of pure cholesterol (99·5 mole%). In addition to analysis of the thermograph by an existing method a new and more rapid procedure has been used for evaluation of the purity of substances. Evidence is given that differential scanning calorimetry measurements at low scanning rates (0·5,1° min−1), followed by correction for premelting, are essential for estimation of ΔHf of substances not ultra-pure, at higher scanning rates large errors result. The entropy of fusion of cholesterol is similar to that of the simpler cholesteryl esters.
{"title":"Thermal properties of cholesterol and estimation of impurity by differential scanning calorimetry.","authors":"W L Gent","doi":"10.1088/0022-3735/2/1/317","DOIUrl":"https://doi.org/10.1088/0022-3735/2/1/317","url":null,"abstract":"Differential scanning calorimetry has been used to investigate the heat of fusion (ΔHf=7·12 kcal per g mol) and true melting temperature (T0=422·4°K) of pure cholesterol (99·5 mole%). In addition to analysis of the thermograph by an existing method a new and more rapid procedure has been used for evaluation of the purity of substances. Evidence is given that differential scanning calorimetry measurements at low scanning rates (0·5,1° min−1), followed by correction for premelting, are essential for estimation of ΔHf of substances not ultra-pure, at higher scanning rates large errors result. The entropy of fusion of cholesterol is similar to that of the simpler cholesteryl esters.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":"2 1","pages":"69-72"},"PeriodicalIF":0.0,"publicationDate":"1969-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/1/317","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16871199","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}
Pub Date : 1969-01-01DOI: 10.1088/0022-3735/2/1/321
E T Hutchings, D M Nutbourne, J D Howse
A description is given of a Perspex membrane-cell used to study the rate of active transport of sodium across a living isolated frog-skin in experiments in which the hydrostatic pressures are controlled on each side of the skin. The circuits used to supply the skin with oxygenated solutions at constant pressure and flow are also outlined.
{"title":"A Perspex membrane-cell used in the study of active transport of sodium across isolated living frog-skins when the hydrostatic pressures are controlled on each side of the skin.","authors":"E T Hutchings, D M Nutbourne, J D Howse","doi":"10.1088/0022-3735/2/1/321","DOIUrl":"https://doi.org/10.1088/0022-3735/2/1/321","url":null,"abstract":"A description is given of a Perspex membrane-cell used to study the rate of active transport of sodium across a living isolated frog-skin in experiments in which the hydrostatic pressures are controlled on each side of the skin. The circuits used to supply the skin with oxygenated solutions at constant pressure and flow are also outlined.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":"2 1","pages":"87-92"},"PeriodicalIF":0.0,"publicationDate":"1969-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/1/321","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16871200","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}
Pub Date : 1968-12-01DOI: 10.1088/0022-3735/1/12/317
B J Bellhouse, F H Bellhouse
The design, manufacture and calibration of a range of thin-film, heated-element gauges to measure instantaneous velocity or skin-friction in air, water or blood is described. The probes consist of a platinum resistance thermometer which is heated electrically, with additional elements to detect reversed flow. The manufacturing technique of a flush-mounted skin-friction gauge, and a needle probe currently used in the diagnosis of heart conditions in man, is described in detail.
{"title":"Thin-film gauges for the measurement of velocity or skin friction in air, water or blood.","authors":"B J Bellhouse, F H Bellhouse","doi":"10.1088/0022-3735/1/12/317","DOIUrl":"https://doi.org/10.1088/0022-3735/1/12/317","url":null,"abstract":"The design, manufacture and calibration of a range of thin-film, heated-element gauges to measure instantaneous velocity or skin-friction in air, water or blood is described. The probes consist of a platinum resistance thermometer which is heated electrically, with additional elements to detect reversed flow. The manufacturing technique of a flush-mounted skin-friction gauge, and a needle probe currently used in the diagnosis of heart conditions in man, is described in detail.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":"1 12","pages":"1211-3"},"PeriodicalIF":0.0,"publicationDate":"1968-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/12/317","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16778721","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}
Pub Date : 1968-12-01DOI: 10.1088/0022-3735/1/12/202
D G Wyatt
The electromagnetic blood flowmeter is an important tool with both medical research and clinical applications. Its principles and development are reviewed; the subjects discussed include head design, transformer e.m.fs, catheter devices, electronic systems, baseline stability, calibration and commercial instruments.
{"title":"The electromagnetic blood flowmeter.","authors":"D G Wyatt","doi":"10.1088/0022-3735/1/12/202","DOIUrl":"https://doi.org/10.1088/0022-3735/1/12/202","url":null,"abstract":"The electromagnetic blood flowmeter is an important tool with both medical research and clinical applications. Its principles and development are reviewed; the subjects discussed include head design, transformer e.m.fs, catheter devices, electronic systems, baseline stability, calibration and commercial instruments.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":"1 12","pages":"1146-52"},"PeriodicalIF":0.0,"publicationDate":"1968-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/12/202","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16778720","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}
Pub Date : 1968-11-01DOI: 10.1088/0022-3735/1/11/305
R S Paden, W C Nixon
A wide range of electron impact energies in the scanning electron microscope can be achieved by varying the specimen potential with respect to the gun potential. Bulk and thin film specimens can be examined and the method also enables a direct representation of potential distributions in electrode structures to be obtained. Some preliminary results are shown and the technique offers an extension of the applications of the scanning electron microscope.
{"title":"Retarding field scanning electron microscopy.","authors":"R S Paden, W C Nixon","doi":"10.1088/0022-3735/1/11/305","DOIUrl":"https://doi.org/10.1088/0022-3735/1/11/305","url":null,"abstract":"A wide range of electron impact energies in the scanning electron microscope can be achieved by varying the specimen potential with respect to the gun potential. Bulk and thin film specimens can be examined and the method also enables a direct representation of potential distributions in electrode structures to be obtained. Some preliminary results are shown and the technique offers an extension of the applications of the scanning electron microscope.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":"1 11","pages":"1073-80"},"PeriodicalIF":0.0,"publicationDate":"1968-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/1/11/305","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16783110","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}
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