Pub Date : 1989-11-01DOI: 10.1088/0022-3735/22/11/001
F. Gro̸nlund
A feedback system was designed for a Cahn RG microbalance with rational use of control system theory to obtain critical damping and error integration. The former efficiently cuts transient effects and settling time, while the latter makes the steady-state error zero so that effects of nonlinearity vanish. The required transfer functions were realised with operational amplifiers and suitable impedances. The modified balance responds quickly (step response error less than 1% in 5 s), the noise level is reduced to 0.3 mu g, and in the steady state the null position is load-independent. Because coil current, rather than voltage, was chosen as the feedback quantity, the temperature coefficient of the compensating electromagnetic torque was reduced to less than 2*10-4 K-1, making temperature compensation superfluous. Detailed prescriptions are given so as to permit application of the procedure to other electromagnetic measuring devices, including balances, with the improvement in performance this may give.
{"title":"Synthesis of feedback control unit for beam microbalances","authors":"F. Gro̸nlund","doi":"10.1088/0022-3735/22/11/001","DOIUrl":"https://doi.org/10.1088/0022-3735/22/11/001","url":null,"abstract":"A feedback system was designed for a Cahn RG microbalance with rational use of control system theory to obtain critical damping and error integration. The former efficiently cuts transient effects and settling time, while the latter makes the steady-state error zero so that effects of nonlinearity vanish. The required transfer functions were realised with operational amplifiers and suitable impedances. The modified balance responds quickly (step response error less than 1% in 5 s), the noise level is reduced to 0.3 mu g, and in the steady state the null position is load-independent. Because coil current, rather than voltage, was chosen as the feedback quantity, the temperature coefficient of the compensating electromagnetic torque was reduced to less than 2*10-4 K-1, making temperature compensation superfluous. Detailed prescriptions are given so as to permit application of the procedure to other electromagnetic measuring devices, including balances, with the improvement in performance this may give.","PeriodicalId":16791,"journal":{"name":"Journal of Physics E: Scientific Instruments","volume":"16 1","pages":"899-903"},"PeriodicalIF":0.0,"publicationDate":"1989-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88173489","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 : 1989-11-01DOI: 10.1088/0022-3735/22/11/009
L. Kraus
A novel method for measurement of the saturation magnetostriction constant of metallic glass ribbons is described. The magnetostriction constant is calculated from the change of the effective anisotropy field induced by a tensile stress applied to the ribbon. The determination of the effective anisotropy field makes use of the measurement of the biased transverse susceptibility. The new method is applicable to both high and low magnetostrictive metallic glasses and it is especially appropriate for wider ribbons.
{"title":"A novel method for measurement of the saturation magnetostriction of amorphous ribbons","authors":"L. Kraus","doi":"10.1088/0022-3735/22/11/009","DOIUrl":"https://doi.org/10.1088/0022-3735/22/11/009","url":null,"abstract":"A novel method for measurement of the saturation magnetostriction constant of metallic glass ribbons is described. The magnetostriction constant is calculated from the change of the effective anisotropy field induced by a tensile stress applied to the ribbon. The determination of the effective anisotropy field makes use of the measurement of the biased transverse susceptibility. The new method is applicable to both high and low magnetostrictive metallic glasses and it is especially appropriate for wider ribbons.","PeriodicalId":16791,"journal":{"name":"Journal of Physics E: Scientific Instruments","volume":"34 1","pages":"943-947"},"PeriodicalIF":0.0,"publicationDate":"1989-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90832227","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 : 1989-11-01DOI: 10.1088/0022-3735/22/11/008
G. Kovács, P. Heszler, Z. Bor, J. Hebling, J. Klebniczki
The switching characteristics of a thyratron-switched low pressure N2 laser was studied. Under optimal conditions +or-100 ps short-term shot-to-shot jitter was achieved. Using an active feedback loop, +or-230 ps long-term stability of switching time was obtained. The results can also be used in designing excimer lasers.
{"title":"Improved jitter and long-term stability of N2 lasers","authors":"G. Kovács, P. Heszler, Z. Bor, J. Hebling, J. Klebniczki","doi":"10.1088/0022-3735/22/11/008","DOIUrl":"https://doi.org/10.1088/0022-3735/22/11/008","url":null,"abstract":"The switching characteristics of a thyratron-switched low pressure N2 laser was studied. Under optimal conditions +or-100 ps short-term shot-to-shot jitter was achieved. Using an active feedback loop, +or-230 ps long-term stability of switching time was obtained. The results can also be used in designing excimer lasers.","PeriodicalId":16791,"journal":{"name":"Journal of Physics E: Scientific Instruments","volume":"35 1","pages":"940-942"},"PeriodicalIF":0.0,"publicationDate":"1989-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78337041","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 : 1989-11-01DOI: 10.1088/0022-3735/22/11/006
M. Benammar, W. C. Maskell
Electronic circuitry powered from a single 24 V supply, based upon a Wheatstone bridge for controlling the temperature of planar thick-film platinum heaters, has been developed. A novel circuit modification was introduced to control the rate of temperature rise when switching on from cold without detracting from the response to convective perturbation at the operating temperature. Gas sensors operating at temperatures up to 900 degrees C represent an important application of this technology.
{"title":"Temperature control of thick-film printed heaters","authors":"M. Benammar, W. C. Maskell","doi":"10.1088/0022-3735/22/11/006","DOIUrl":"https://doi.org/10.1088/0022-3735/22/11/006","url":null,"abstract":"Electronic circuitry powered from a single 24 V supply, based upon a Wheatstone bridge for controlling the temperature of planar thick-film platinum heaters, has been developed. A novel circuit modification was introduced to control the rate of temperature rise when switching on from cold without detracting from the response to convective perturbation at the operating temperature. Gas sensors operating at temperatures up to 900 degrees C represent an important application of this technology.","PeriodicalId":16791,"journal":{"name":"Journal of Physics E: Scientific Instruments","volume":"54 1","pages":"933-936"},"PeriodicalIF":0.0,"publicationDate":"1989-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73258289","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 : 1989-11-01DOI: 10.1088/0022-3735/22/11/004
D. Dunstan, I. Spain
The authors provide a guide to the selection, design and construction of diamond anvil high-pressure cells. It is addressed primarily to those working in the pressure range up to approximately 30 GPa (300 kbar). Design principles are discussed, together with details that enable either a beginner or practitioner to design a cell tailored to specific research needs. Three basic cell designs are also given.
{"title":"Technology of diamond anvil high-pressure cells: I. Principles, design and construction","authors":"D. Dunstan, I. Spain","doi":"10.1088/0022-3735/22/11/004","DOIUrl":"https://doi.org/10.1088/0022-3735/22/11/004","url":null,"abstract":"The authors provide a guide to the selection, design and construction of diamond anvil high-pressure cells. It is addressed primarily to those working in the pressure range up to approximately 30 GPa (300 kbar). Design principles are discussed, together with details that enable either a beginner or practitioner to design a cell tailored to specific research needs. Three basic cell designs are also given.","PeriodicalId":16791,"journal":{"name":"Journal of Physics E: Scientific Instruments","volume":"63 1","pages":"913-923"},"PeriodicalIF":0.0,"publicationDate":"1989-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82172435","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 : 1989-11-01DOI: 10.1088/0022-3735/22/11/013
P. Wraight
A description is given of a reference light source constructed for use with a three-channel airglow spectrometer. It uses the principle of the integrating sphere, to meet the requirements of compactness and portability, supplying approximately white light of low and uniform radiance and of selected intensity into each of three apertures of diameter about 100 mm.
{"title":"A compact low-radiance multichannel reference source of diffuse visible and near-infrared radiation for airglow studies","authors":"P. Wraight","doi":"10.1088/0022-3735/22/11/013","DOIUrl":"https://doi.org/10.1088/0022-3735/22/11/013","url":null,"abstract":"A description is given of a reference light source constructed for use with a three-channel airglow spectrometer. It uses the principle of the integrating sphere, to meet the requirements of compactness and portability, supplying approximately white light of low and uniform radiance and of selected intensity into each of three apertures of diameter about 100 mm.","PeriodicalId":16791,"journal":{"name":"Journal of Physics E: Scientific Instruments","volume":"30 1","pages":"962-963"},"PeriodicalIF":0.0,"publicationDate":"1989-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82774354","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 : 1989-11-01DOI: 10.1088/0022-3735/22/11/015
J. Lux, B. Coquart
A 5 m multipass cell has been designed for absorption measurements concerned with atmospheric compounds. It can operate in a temperature range down to 215 K and the optics have been chosen for studies in the ultraviolet spectral region. Measurements have been made with path lengths up to 160 m between 195 and 310 nm at ambient temperature, at 240 and 220 K.
{"title":"DESIGN NOTE: A cooled multipass cell for the absorption study of atmospheric compounds","authors":"J. Lux, B. Coquart","doi":"10.1088/0022-3735/22/11/015","DOIUrl":"https://doi.org/10.1088/0022-3735/22/11/015","url":null,"abstract":"A 5 m multipass cell has been designed for absorption measurements concerned with atmospheric compounds. It can operate in a temperature range down to 215 K and the optics have been chosen for studies in the ultraviolet spectral region. Measurements have been made with path lengths up to 160 m between 195 and 310 nm at ambient temperature, at 240 and 220 K.","PeriodicalId":16791,"journal":{"name":"Journal of Physics E: Scientific Instruments","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"1989-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74294170","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 : 1989-11-01DOI: 10.1088/0022-3735/22/11/007
T. York, R. Porter
A microprocessor-based arbitrary-waveform generator has been designed and constructed to provide synchronised tuning for scientific instruments during collection of data. The instrument utilises a piecewise quadratic algorithm to interpolate the required values on the generated curves. It replaces existing techniques, which typically offer a range of analytical solutions to the problem, each of which is essentially inappropriate for the application. The new instrument can simultaneously provide four independent output curves, of arbitrary shape, each containing up to 4096 points having 8-bit resolution. Scanning rates as high as 1 ms per data point can be used. The instrument has been tested using electron energy-loss and photoelectron spectrometers and it is reported to satisfy requirements. The prototype has been used in a photoelectron study of molecular oxygen and has enabled improved results to be obtained.
{"title":"An arbitrary-waveform generator for tuning spectrometers","authors":"T. York, R. Porter","doi":"10.1088/0022-3735/22/11/007","DOIUrl":"https://doi.org/10.1088/0022-3735/22/11/007","url":null,"abstract":"A microprocessor-based arbitrary-waveform generator has been designed and constructed to provide synchronised tuning for scientific instruments during collection of data. The instrument utilises a piecewise quadratic algorithm to interpolate the required values on the generated curves. It replaces existing techniques, which typically offer a range of analytical solutions to the problem, each of which is essentially inappropriate for the application. The new instrument can simultaneously provide four independent output curves, of arbitrary shape, each containing up to 4096 points having 8-bit resolution. Scanning rates as high as 1 ms per data point can be used. The instrument has been tested using electron energy-loss and photoelectron spectrometers and it is reported to satisfy requirements. The prototype has been used in a photoelectron study of molecular oxygen and has enabled improved results to be obtained.","PeriodicalId":16791,"journal":{"name":"Journal of Physics E: Scientific Instruments","volume":"32 1","pages":"937-939"},"PeriodicalIF":0.0,"publicationDate":"1989-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82107528","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 : 1989-11-01DOI: 10.1088/0022-3735/22/11/003
M. Kano
An adiabatic calorimeter has been developed for the purpose of calorimetry in the solid, liquid and supercooled phases of metals in vacuum or inert gas atmospheres. Heat capacity was measured with heat supplied by an external drive system, in which the power output of a DC stabilised power source is interlocked with the rotation of a motor. For measurement of the specimen temperature, a chromel-constantan thermocouple was used, and heat was supplied uniformly by a constantan heater wound around a crucible. The temperature of the adiabatic system was programmed PID controlled, and stability was maintained within +or-0.009 K min-1 in the region of 300-700 K even when supplying heat to the specimens. Using a crucible made of fused quartz, pure bismuth was supercooled to 30 K; the enthalpy of fusion was measured as 11478 J mol-1, and the entropy of fusion as 21.077 J mol-1 K-1. The measured values of both the enthalpy and entropy of fusion, and the values of the heat capacity in the solid and the liquid phases all showed good agreement with values in the literature, and it was shown that stable measurement of heat capacity in the solid, liquid and supercooled phases using the same specimen and apparatus is possible.
研制了一种绝热量热计，用于在真空或惰性气体环境中测量金属的固体、液体和过冷相的量热。热容是通过外部驱动系统提供的热量来测量的，其中直流稳定电源的输出功率与电机的旋转互锁。为了测量试样温度，使用了铬合金-康坦热电偶，并通过缠绕在坩埚周围的康坦加热器均匀地提供热量。绝热系统温度采用程控PID控制，在300-700 K范围内，即使给试样加热，也能保持在+or-0.009 K min-1范围内的稳定性。使用熔融石英制成的坩埚，将纯铋过冷至30k;聚变焓为11478 J mol-1，聚变熵为21.077 J mol-1 K-1。熔合焓和熔合熵的测量值以及固液相热容的测量值均与文献相符，表明用同一试样和仪器可以稳定地测量固液相和过冷相的热容。
{"title":"Adiabatic calorimeter for the purpose of calorimetry in the solid, liquid and supercooled phases of metals","authors":"M. Kano","doi":"10.1088/0022-3735/22/11/003","DOIUrl":"https://doi.org/10.1088/0022-3735/22/11/003","url":null,"abstract":"An adiabatic calorimeter has been developed for the purpose of calorimetry in the solid, liquid and supercooled phases of metals in vacuum or inert gas atmospheres. Heat capacity was measured with heat supplied by an external drive system, in which the power output of a DC stabilised power source is interlocked with the rotation of a motor. For measurement of the specimen temperature, a chromel-constantan thermocouple was used, and heat was supplied uniformly by a constantan heater wound around a crucible. The temperature of the adiabatic system was programmed PID controlled, and stability was maintained within +or-0.009 K min-1 in the region of 300-700 K even when supplying heat to the specimens. Using a crucible made of fused quartz, pure bismuth was supercooled to 30 K; the enthalpy of fusion was measured as 11478 J mol-1, and the entropy of fusion as 21.077 J mol-1 K-1. The measured values of both the enthalpy and entropy of fusion, and the values of the heat capacity in the solid and the liquid phases all showed good agreement with values in the literature, and it was shown that stable measurement of heat capacity in the solid, liquid and supercooled phases using the same specimen and apparatus is possible.","PeriodicalId":16791,"journal":{"name":"Journal of Physics E: Scientific Instruments","volume":"81 3-4","pages":"907-912"},"PeriodicalIF":0.0,"publicationDate":"1989-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72603014","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 : 1989-11-01DOI: 10.1088/0022-3735/22/11/005
I. Spain, D. Dunstan
For pt.I see ibid., vol.22, no.11, p.913-23, Nov. 1989. The operation and use of diamond anvil cells is discussed. Experimental details pertaining to the assembly of cells preparation of gaskets, compressing media, sample preparation and handling, pressure measurement and types of spectroscopic and electrical measurement which can be carried out are given.
{"title":"The technology of diamond anvil high-pressure cells. II: Operation and use","authors":"I. Spain, D. Dunstan","doi":"10.1088/0022-3735/22/11/005","DOIUrl":"https://doi.org/10.1088/0022-3735/22/11/005","url":null,"abstract":"For pt.I see ibid., vol.22, no.11, p.913-23, Nov. 1989. The operation and use of diamond anvil cells is discussed. Experimental details pertaining to the assembly of cells preparation of gaskets, compressing media, sample preparation and handling, pressure measurement and types of spectroscopic and electrical measurement which can be carried out are given.","PeriodicalId":16791,"journal":{"name":"Journal of Physics E: Scientific Instruments","volume":"8 1","pages":"923-933"},"PeriodicalIF":0.0,"publicationDate":"1989-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78496082","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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