Pub Date : 1969-12-01DOI: 10.1088/0022-3735/2/12/433
D Staynov, G Stainov
A double-beam recording spectrodensitometer has been constructed to measure the optical density of dry agar electrophoregrammes. The measuring and reference beams are modulated with different frequencies. Two resonance amplifiers separate the signals. The electronic logarithmic recording is independent of the nonlinear characteristics of the valves.
{"title":"A double-beam recording spectrodensitometer.","authors":"D Staynov, G Stainov","doi":"10.1088/0022-3735/2/12/433","DOIUrl":"https://doi.org/10.1088/0022-3735/2/12/433","url":null,"abstract":"A double-beam recording spectrodensitometer has been constructed to measure the optical density of dry agar electrophoregrammes. The measuring and reference beams are modulated with different frequencies. Two resonance amplifiers separate the signals. The electronic logarithmic recording is independent of the nonlinear characteristics of the valves.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1969-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/12/433","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16442759","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 : 1969-12-01DOI: 10.1088/0022-3735/2/12/301
W J Megaw, A C Wells
A simple and easily constructed spectrometer is described by which it is possible to measure the electrical mobilities of submicrometre radioactive aerosol particles with an estimated absolute accuracy to ±4% and a relative accuracy to ±05%. The resolution of the instrument is 3% in mobility.
{"title":"A high resolution charge and mobility spectrometer for radioactive submicrometre aerosols.","authors":"W J Megaw, A C Wells","doi":"10.1088/0022-3735/2/12/301","DOIUrl":"https://doi.org/10.1088/0022-3735/2/12/301","url":null,"abstract":"A simple and easily constructed spectrometer is described by which it is possible to measure the electrical mobilities of submicrometre radioactive aerosol particles with an estimated absolute accuracy to ±4% and a relative accuracy to ±05%. The resolution of the instrument is 3% in mobility.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1969-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/12/301","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16442756","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 : 1969-12-01DOI: 10.1088/0022-3735/2/12/319
T K Chowdhury
Glass micropipette electrodes with extremely fine tips and high mechanical rigidity have been fabricated with a semi-automatic pipette-puller. The fabrication involves a two stage pull of a heated glass capillary held horizontally by a pair of non-slip clamps. Air is automatically blown from symmetrically located nozzles on to the softened portion of the capillary at the onset of the second pull. With this technique micropipettes with a relatively short taper and large cone angle at the very tip are produced, which not only possess high mechanical rigidity, but also a fineness at the tip (500 A or less). A special advantage of the large cone angle at the tip is that such an electrode has a much lower electrical impedance than a conventional micropipette electrode with a comparable tip diameter. The size and shape of the micropipette can be easily altered to meet the specific need. The principle of differential vapour pressure has been utilized to fill the micropipettes with the desired electrolytes. A vibration technique for inserting a microelectrode into living cells is also described.
{"title":"Fabrication of extremely fine glass micropipette electrodes.","authors":"T K Chowdhury","doi":"10.1088/0022-3735/2/12/319","DOIUrl":"https://doi.org/10.1088/0022-3735/2/12/319","url":null,"abstract":"Glass micropipette electrodes with extremely fine tips and high mechanical rigidity have been fabricated with a semi-automatic pipette-puller. The fabrication involves a two stage pull of a heated glass capillary held horizontally by a pair of non-slip clamps. Air is automatically blown from symmetrically located nozzles on to the softened portion of the capillary at the onset of the second pull. With this technique micropipettes with a relatively short taper and large cone angle at the very tip are produced, which not only possess high mechanical rigidity, but also a fineness at the tip (500 A or less). A special advantage of the large cone angle at the tip is that such an electrode has a much lower electrical impedance than a conventional micropipette electrode with a comparable tip diameter. The size and shape of the micropipette can be easily altered to meet the specific need. The principle of differential vapour pressure has been utilized to fill the micropipettes with the desired electrolytes. A vibration technique for inserting a microelectrode into living cells is also described.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1969-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/12/319","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16442758","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 : 1969-12-01DOI: 10.1088/0022-3735/2/12/302
C M Killick
A conductivity cell incorporating the impingement principle suggested by Nash has been designed to facilitate the continuous measurement of atmospheric sulphur dioxide. The instrument based on this cell is provided with several measuring ranges which can be selected to give full scale deflection from 0·2 to 5 p.p.m. sulphur dioxide.
{"title":"An improved conductivity cell for the continuous measurement of sulphur dioxide in the atmosphere.","authors":"C M Killick","doi":"10.1088/0022-3735/2/12/302","DOIUrl":"https://doi.org/10.1088/0022-3735/2/12/302","url":null,"abstract":"A conductivity cell incorporating the impingement principle suggested by Nash has been designed to facilitate the continuous measurement of atmospheric sulphur dioxide. The instrument based on this cell is provided with several measuring ranges which can be selected to give full scale deflection from 0·2 to 5 p.p.m. sulphur dioxide.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1969-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/12/302","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16442757","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 : 1969-11-01DOI: 10.1088/0022-3735/2/11/308
B J Bellhouse, F H Bellhouse, A Gunning
A thin-film gauge to measure instantaneous fluid velocity is described. The element, which consists of a platinum thermometer, is cemented into a straight hypodermic needle of 0·75 mm outside diameter and heated electrically to 10 degc above ambient temperature. Heat is removed by forced convection and is related to instantaneous velocity. Calibrations of the probe in water for various angles of inclination to the stream are obtained and a simple method of detecting reversed flow is described. Identical calibrations in water and blood are found, despite a fourfold difference in kinematic viscosity, and an explanation of this effect is advanced.
{"title":"A straight needle-probe for the measurement of blood velocity.","authors":"B J Bellhouse, F H Bellhouse, A Gunning","doi":"10.1088/0022-3735/2/11/308","DOIUrl":"https://doi.org/10.1088/0022-3735/2/11/308","url":null,"abstract":"A thin-film gauge to measure instantaneous fluid velocity is described. The element, which consists of a platinum thermometer, is cemented into a straight hypodermic needle of 0·75 mm outside diameter and heated electrically to 10 degc above ambient temperature. Heat is removed by forced convection and is related to instantaneous velocity. Calibrations of the probe in water for various angles of inclination to the stream are obtained and a simple method of detecting reversed flow is described. Identical calibrations in water and blood are found, despite a fourfold difference in kinematic viscosity, and an explanation of this effect is advanced.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1969-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/11/308","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16432487","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 : 1969-11-01DOI: 10.1088/0022-3735/2/11/306
A D Beach
A mechanical joint has been devised which gives two degrees of freedom to each of three joints in a laser beam steering linkage. This allows accurate counterbalancing of the system and, in conjunction with a CO2 laser, makes the device suitable for use as a surgical tool in `bloodless surgery'.
{"title":"A laser manipulator for surgical use.","authors":"A D Beach","doi":"10.1088/0022-3735/2/11/306","DOIUrl":"https://doi.org/10.1088/0022-3735/2/11/306","url":null,"abstract":"A mechanical joint has been devised which gives two degrees of freedom to each of three joints in a laser beam steering linkage. This allows accurate counterbalancing of the system and, in conjunction with a CO2 laser, makes the device suitable for use as a surgical tool in `bloodless surgery'.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1969-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/11/306","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16432486","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 : 1969-10-01DOI: 10.1088/0022-3735/2/10/308
K D Cliff
A simple and reliable optical density discriminator is described which possesses a high discrimination sensitivity and low drift.
{"title":"A density discriminator for use in radiation dosimetry by photographic film.","authors":"K D Cliff","doi":"10.1088/0022-3735/2/10/308","DOIUrl":"https://doi.org/10.1088/0022-3735/2/10/308","url":null,"abstract":"A simple and reliable optical density discriminator is described which possesses a high discrimination sensitivity and low drift.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1969-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/10/308","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16423892","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 : 1969-10-01DOI: 10.1088/0022-3735/2/10/420
E F Keen, P J Calver
The device described in this note is an automatic means of producing audio signals at random time intervals, and was devised for a work-study project. The system used could be adapted easily for other purposes, for example to the automating of biological experiments requiring random stimuli for behaviour patterns, or to the random sampling of items on a conveyor belt. The system may be used with multichannel outputs and other parameters, e.g. the number of items or events can be used instead of time.
{"title":"Programmed random time interval signalling device.","authors":"E F Keen, P J Calver","doi":"10.1088/0022-3735/2/10/420","DOIUrl":"https://doi.org/10.1088/0022-3735/2/10/420","url":null,"abstract":"The device described in this note is an automatic means of producing audio signals at random time intervals, and was devised for a work-study project. The system used could be adapted easily for other purposes, for example to the automating of biological experiments requiring random stimuli for behaviour patterns, or to the random sampling of items on a conveyor belt. The system may be used with multichannel outputs and other parameters, e.g. the number of items or events can be used instead of time.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1969-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/10/420","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16423893","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 : 1969-09-01DOI: 10.1088/0022-3735/2/9/310
J Hodby
The input analogue-to-digital converters of currently available averaging computers have a finite resolution. It is shown that in the presence of noise of 1/f character, this finite resolution sets an upper limit to the possible improvement of signal-to-noise ratio. This limit can be exceeded only if the d.c. level of the input signal is periodically reset. The performance of an electronic circuit designed to do this automatically is described.
{"title":"An aid to the use of averaging computers in experimental investigations.","authors":"J Hodby","doi":"10.1088/0022-3735/2/9/310","DOIUrl":"https://doi.org/10.1088/0022-3735/2/9/310","url":null,"abstract":"The input analogue-to-digital converters of currently available averaging computers have a finite resolution. It is shown that in the presence of noise of 1/f character, this finite resolution sets an upper limit to the possible improvement of signal-to-noise ratio. This limit can be exceeded only if the d.c. level of the input signal is periodically reset. The performance of an electronic circuit designed to do this automatically is described.","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1969-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/9/310","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16885799","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 : 1969-08-01DOI: 10.1088/0022-3735/2/8/317
G C Joyce, G C Wilson
Abstract : A simple reversible linear motor which steps along a precision track is described. Step size can be varied within the range 0.1 - 5.0 um and final motor position can be adjusted to 0.01 um. More complex versions of the motor and control circuits are also described. The motor uses a piezo-electric tube as the driving element which operates in conjunction with electromagnetic clamps to generate progressive movement. (Author)
{"title":"Micro-step motor.","authors":"G C Joyce, G C Wilson","doi":"10.1088/0022-3735/2/8/317","DOIUrl":"https://doi.org/10.1088/0022-3735/2/8/317","url":null,"abstract":"Abstract : A simple reversible linear motor which steps along a precision track is described. Step size can be varied within the range 0.1 - 5.0 um and final motor position can be adjusted to 0.01 um. More complex versions of the motor and control circuits are also described. The motor uses a piezo-electric tube as the driving element which operates in conjunction with electromagnetic clamps to generate progressive movement. (Author)","PeriodicalId":16983,"journal":{"name":"Journal of Scientific Instruments","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1969-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1088/0022-3735/2/8/317","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"16881264","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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