Pub Date : 2017-10-28DOI: 10.1109/jrproc.1934.227896
S. S. Kirby, L. Berkner, T. R. Gilliland, K. Norton
Radio observations of the heights of the several layers of the ionosphere were made at Washington, D.C., and Sydney, Nova Scotia, by the pulse method during the afternoon of the solar eclipse of August 31, 1932, and during the afternoons of several days preceding and following. At Washington three separate groups of determinations were made: (1) Measurements of the maximum ionization of the E layer during the afternoon; (2) continual series of measurements of virtual height during the afternoon at 4200 kilocycles which was ordinarily just above the F1critical frequency for the ordinary ray; (3) measurements of the critical frequency of the F2layer during the afternoon. At Sydney, determinations similar to (1) were made and continuous records of virtual height were obtained at 2400 and 3000 kilocycles. Separate equipment was used for each of these groups of determinations so that measurements could be made rapidly and continuously. It was found that the ionization of the E layer decreased to about 30 per cent of its normal value at the time of the eclipse maximum, the variation taking place approximately in phase with the eclipse. The ionization of the F1layer likewise decreased in almost exactly the same manner, reaching a value of about 40 per cent of its normal ionization at about the eclipse maximum. When analyzed by the method presented in this paper, observations of other investigators are found to agree well with these results.
{"title":"Radio Observations of the Bureau of Standards during the Solar Eclipse of August 31, 1932","authors":"S. S. Kirby, L. Berkner, T. R. Gilliland, K. Norton","doi":"10.1109/jrproc.1934.227896","DOIUrl":"https://doi.org/10.1109/jrproc.1934.227896","url":null,"abstract":"Radio observations of the heights of the several layers of the ionosphere were made at Washington, D.C., and Sydney, Nova Scotia, by the pulse method during the afternoon of the solar eclipse of August 31, 1932, and during the afternoons of several days preceding and following. At Washington three separate groups of determinations were made: (1) Measurements of the maximum ionization of the E layer during the afternoon; (2) continual series of measurements of virtual height during the afternoon at 4200 kilocycles which was ordinarily just above the F1critical frequency for the ordinary ray; (3) measurements of the critical frequency of the F2layer during the afternoon. At Sydney, determinations similar to (1) were made and continuous records of virtual height were obtained at 2400 and 3000 kilocycles. Separate equipment was used for each of these groups of determinations so that measurements could be made rapidly and continuously. It was found that the ionization of the E layer decreased to about 30 per cent of its normal value at the time of the eclipse maximum, the variation taking place approximately in phase with the eclipse. The ionization of the F1layer likewise decreased in almost exactly the same manner, reaching a value of about 40 per cent of its normal ionization at about the eclipse maximum. When analyzed by the method presented in this paper, observations of other investigators are found to agree well with these results.","PeriodicalId":54574,"journal":{"name":"Proceedings of the Institute of Radio Engineers","volume":"22 1","pages":"247-264"},"PeriodicalIF":0.0,"publicationDate":"2017-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/jrproc.1934.227896","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44690465","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 : 2017-10-28DOI: 10.1109/JRPROC.1932.227589
T. R. Gilliland, G. W. Kenrick
This paper describes a preliminary installation of a continuous automatic recorder of virtual heights of the Kennelly-Heaviside layer. This installation requires that a chopper at the transmitter and a revolving mirror at the receiving station be driven by synchronous motors connected to the same power system. The group retardation method of Breit and Tuve is used with a few modifications which permit continuous records to be made. Suggestions are made for improvements which might be incorporated in a permanent installation.
{"title":"Preliminary Note on an Automatic Recorder Giving a Continuous Height Record of the Kennelly-Heaviside Layer","authors":"T. R. Gilliland, G. W. Kenrick","doi":"10.1109/JRPROC.1932.227589","DOIUrl":"https://doi.org/10.1109/JRPROC.1932.227589","url":null,"abstract":"This paper describes a preliminary installation of a continuous automatic recorder of virtual heights of the Kennelly-Heaviside layer. This installation requires that a chopper at the transmitter and a revolving mirror at the receiving station be driven by synchronous motors connected to the same power system. The group retardation method of Breit and Tuve is used with a few modifications which permit continuous records to be made. Suggestions are made for improvements which might be incorporated in a permanent installation.","PeriodicalId":54574,"journal":{"name":"Proceedings of the Institute of Radio Engineers","volume":"20 1","pages":"540-547"},"PeriodicalIF":0.0,"publicationDate":"2017-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/JRPROC.1932.227589","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45149352","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 : 2017-10-27DOI: 10.1109/jrproc.1932.227522
T. R. Gilliland, G. W. Kenrick, K. Norton
The results of observations of the height of the Kennelly-Heaviside layer carried out near Washington, D.C., during 1930 are presented. Evidence for the existence of two layers (corresponding closely in virtual height to the E and F regions discussed by Appleton) is found during daylight on frequencies between three and five megacycles. The modification in the virtual height of the higher F layer produced by the existence of a low E layer is investigated theoretically, and the possibility of large changes in virtual height near the highest frequency returned by the E layer is pointed out. A number of oscillograms showing the characteristic types of records observed during the tests are presented together with a graph of average heights from January to October, 1930.
{"title":"Investigations of Kennelly-Heaviside Layer Heights for Frequencies between 1600 and 8650 Kilocycles per Second","authors":"T. R. Gilliland, G. W. Kenrick, K. Norton","doi":"10.1109/jrproc.1932.227522","DOIUrl":"https://doi.org/10.1109/jrproc.1932.227522","url":null,"abstract":"The results of observations of the height of the Kennelly-Heaviside layer carried out near Washington, D.C., during 1930 are presented. Evidence for the existence of two layers (corresponding closely in virtual height to the E and F regions discussed by Appleton) is found during daylight on frequencies between three and five megacycles. The modification in the virtual height of the higher F layer produced by the existence of a low E layer is investigated theoretically, and the possibility of large changes in virtual height near the highest frequency returned by the E layer is pointed out. A number of oscillograms showing the characteristic types of records observed during the tests are presented together with a graph of average heights from January to October, 1930.","PeriodicalId":54574,"journal":{"name":"Proceedings of the Institute of Radio Engineers","volume":"20 1","pages":"286-309"},"PeriodicalIF":0.0,"publicationDate":"2017-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/jrproc.1932.227522","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44485541","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 : 2017-10-27DOI: 10.1109/jrproc.1934.227897
T. R. Gilliland
A system is described which gives a curve of virtual heights of the layers of the ionosphere against frequency. The pulse method of Breit and Tuve is employed with modifications. Short pulses of radio-frequency energy are transmitted, and the time required for the energy to go up and return is recorded automatically by a galvanometer oscillograph of the type previously used for fixed frequency work. The transmitting and receiving sets are shifted in frequency from 2500 to 4400 kilocycles at the uniform rate of 200 kilocycles per minute. Records are presented which show the characteristics for different times of day and night. In the daytime, during the period of these tests, three strata were usually indicated. For the lower range of frequencies, reflections come from the E layer with a virtual height of around 120 kilometers. As frequency is increased the waves pass through the E layer and are returned from the F1layer with virtual heights of the order of 200 kilometers. The frequency for which this transition takes place varies with time of day and with season. In the middle of the day, during these tests, this critical frequency was in the neighborhood of 3000 kilocycles, while the critical frequency for passing through the F1to the F2layer was usually between 3800 and 4100 kilocycles. The F2layer shows virtual heights of 280 kilometers or more.
{"title":"Note on a Multifrequency Automatic Recorder of Ionosphere Heights","authors":"T. R. Gilliland","doi":"10.1109/jrproc.1934.227897","DOIUrl":"https://doi.org/10.1109/jrproc.1934.227897","url":null,"abstract":"A system is described which gives a curve of virtual heights of the layers of the ionosphere against frequency. The pulse method of Breit and Tuve is employed with modifications. Short pulses of radio-frequency energy are transmitted, and the time required for the energy to go up and return is recorded automatically by a galvanometer oscillograph of the type previously used for fixed frequency work. The transmitting and receiving sets are shifted in frequency from 2500 to 4400 kilocycles at the uniform rate of 200 kilocycles per minute. Records are presented which show the characteristics for different times of day and night. In the daytime, during the period of these tests, three strata were usually indicated. For the lower range of frequencies, reflections come from the E layer with a virtual height of around 120 kilometers. As frequency is increased the waves pass through the E layer and are returned from the F1layer with virtual heights of the order of 200 kilometers. The frequency for which this transition takes place varies with time of day and with season. In the middle of the day, during these tests, this critical frequency was in the neighborhood of 3000 kilocycles, while the critical frequency for passing through the F1to the F2layer was usually between 3800 and 4100 kilocycles. The F2layer shows virtual heights of 280 kilometers or more.","PeriodicalId":54574,"journal":{"name":"Proceedings of the Institute of Radio Engineers","volume":"22 1","pages":"236-246"},"PeriodicalIF":0.0,"publicationDate":"2017-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/jrproc.1934.227897","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47910277","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 : 2017-10-27DOI: 10.1109/JRPROC.1934.226688
F. W. Dunmore
{"title":"A Method of Providing Course and Quadrant Identification with the Radio Range Beacon System","authors":"F. W. Dunmore","doi":"10.1109/JRPROC.1934.226688","DOIUrl":"https://doi.org/10.1109/JRPROC.1934.226688","url":null,"abstract":"","PeriodicalId":54574,"journal":{"name":"Proceedings of the Institute of Radio Engineers","volume":"22 1","pages":"119-119"},"PeriodicalIF":0.0,"publicationDate":"2017-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/JRPROC.1934.226688","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49577923","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 : 2013-02-02DOI: 10.1109/ire.1935.6449185
W. L. Barrow
The complex impedance of a vertical half-wave antenna located any distance above an earth of given conductivity and dielectric constant is calculated by the “induced electromotive force” method. Based on the assumption k0≪ |k| (where k0 and k are the wave numbers for the atmosphere and earthy respectively), the results are applicable down to about 10 meters for any earth except a very dry soil. The calculation is based on the Sommerfeld-von Hoerschlemann expression for the field of a dipole above a half space of arbitrary electrical character. After splitting the total impedance into three parts, Z = Z1 + Z2 + Z3, the component Z1 is shown to be the self-impedance of the antenna, Z2 the mutual impedance between the antenna and its perfect image, and Z3 an impedance component due to the finite conductivity of the earth. Z3 is found to be proportional to two factors, one of which depends on the conductivity and dielectric coefficient of the earth and the wavelength and the other of which depends only on the ratio h/λ, where h = antenna height and λ = wavelength. Z3 is put in a form suitable for the computation of any given case and curves are shown for four typical examples. For λ > 10 meters and all except very dry soil, the effect of the finite conductivity is quite small and the assumption, often made, of a perfectly reflecting earth thus is justified for a large number of cases. The impedance is, except for very short waves or exceedingly dry soil, substantially that obtained for a perfectly conducting earth. A principle of similitude is stated, in which two antennas over the same kind of earth and having equal values of h/λ have identical impedances.
{"title":"On the impedance of a vertical half-wave antenna above an earth of finite conductivity","authors":"W. L. Barrow","doi":"10.1109/ire.1935.6449185","DOIUrl":"https://doi.org/10.1109/ire.1935.6449185","url":null,"abstract":"The complex impedance of a vertical half-wave antenna located any distance above an earth of given conductivity and dielectric constant is calculated by the “induced electromotive force” method. Based on the assumption k<inf>0</inf>≪ |k| (where k<inf>0</inf> and k are the wave numbers for the atmosphere and earthy respectively), the results are applicable down to about 10 meters for any earth except a very dry soil. The calculation is based on the Sommerfeld-von Hoerschlemann expression for the field of a dipole above a half space of arbitrary electrical character. After splitting the total impedance into three parts, Z = Z<inf>1</inf> + Z<inf>2</inf> + Z<inf>3</inf>, the component Z<inf>1</inf> is shown to be the self-impedance of the antenna, Z<inf>2</inf> the mutual impedance between the antenna and its perfect image, and Z<inf>3</inf> an impedance component due to the finite conductivity of the earth. Z<inf>3</inf> is found to be proportional to two factors, one of which depends on the conductivity and dielectric coefficient of the earth and the wavelength and the other of which depends only on the ratio h/λ, where h = antenna height and λ = wavelength. Z<inf>3</inf> is put in a form suitable for the computation of any given case and curves are shown for four typical examples. For λ > 10 meters and all except very dry soil, the effect of the finite conductivity is quite small and the assumption, often made, of a perfectly reflecting earth thus is justified for a large number of cases. The impedance is, except for very short waves or exceedingly dry soil, substantially that obtained for a perfectly conducting earth. A principle of similitude is stated, in which two antennas over the same kind of earth and having equal values of h/λ have identical impedances.","PeriodicalId":54574,"journal":{"name":"Proceedings of the Institute of Radio Engineers","volume":"61 1","pages":"150-167"},"PeriodicalIF":0.0,"publicationDate":"2013-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/ire.1935.6449185","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62333472","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 : 1999-10-01DOI: 10.1109/jproc.1999.790645
E. Alexanderson
The possible limitation in the number of long distance radio stations simultaneously in operation is considered. It is shown how high-speed transmission, improved directional selectivity, and better frequency selectivity would greatly increase the number of feasible co-existent stations, The utilization of a wave length band as a result of high-speed transmission is discussed in connection with frequency selectivity. The 200-kilowatt alternator station at New Brunswick is described, special mention being made of the constant speed regulation system for the induction motor drive, the functioning of the magnetic amplifier, and the operation of the multiple antenna. In this latter connection, the possibilities of effective directional radiation are considered.
{"title":"Trans-Oceanic Radio Communication","authors":"E. Alexanderson","doi":"10.1109/jproc.1999.790645","DOIUrl":"https://doi.org/10.1109/jproc.1999.790645","url":null,"abstract":"The possible limitation in the number of long distance radio stations simultaneously in operation is considered. It is shown how high-speed transmission, improved directional selectivity, and better frequency selectivity would greatly increase the number of feasible co-existent stations, The utilization of a wave length band as a result of high-speed transmission is discussed in connection with frequency selectivity. The 200-kilowatt alternator station at New Brunswick is described, special mention being made of the constant speed regulation system for the induction motor drive, the functioning of the magnetic amplifier, and the operation of the multiple antenna. In this latter connection, the possibilities of effective directional radiation are considered.","PeriodicalId":54574,"journal":{"name":"Proceedings of the Institute of Radio Engineers","volume":"8 1","pages":"263-285"},"PeriodicalIF":0.0,"publicationDate":"1999-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/jproc.1999.790645","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62535586","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 : 1997-02-01DOI: 10.1109/JRPROC.1913.216563
M. Pupin
Work during the last three or four years has suggested a method which might prove useful in determining the law of radiation from antennae. There are two ways of arriving at the law of radiation. There is a purely mathematical way, which will be described herein. Starting with the EMF, which can be divided into two components in an infinite number of ways, the author divides the EMF between A and B into components, as follows: E cos pt = A cos(pt-u)- B sin(pt-u) and proceeds to derive the radiation law for radio oscillators.
过去三四年的工作提出了一种方法，这种方法可能对确定天线的辐射规律很有用。得出辐射定律有两种方法。有一种纯数学的方法，将在这里描述。本文从电动势入手，将A和B之间的电动势以无限种方式分成两个分量，将电动势分成如下的分量:E cos pt = A cos(pt-u)- B sin(pt-u)，并推导出无线电振荡器的辐射规律。
{"title":"A discussion on experimental tests of the radiation law for radio oscillators","authors":"M. Pupin","doi":"10.1109/JRPROC.1913.216563","DOIUrl":"https://doi.org/10.1109/JRPROC.1913.216563","url":null,"abstract":"Work during the last three or four years has suggested a method which might prove useful in determining the law of radiation from antennae. There are two ways of arriving at the law of radiation. There is a purely mathematical way, which will be described herein. Starting with the EMF, which can be divided into two components in an infinite number of ways, the author divides the EMF between A and B into components, as follows: E cos pt = A cos(pt-u)- B sin(pt-u) and proceeds to derive the radiation law for radio oscillators.","PeriodicalId":54574,"journal":{"name":"Proceedings of the Institute of Radio Engineers","volume":"1 1","pages":"3-10"},"PeriodicalIF":0.0,"publicationDate":"1997-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/JRPROC.1913.216563","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62285532","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 : 1938-12-01DOI: 10.1109/JRPROC.1938.228178
A. A. Oswald
There is described briefly a short-wave single-side-band system which has been developed for transoceanic radiotelephone service. The system involves the transmission of a reduced carrier or pilot frequency and is designed to include the testing of twin-channel operation wherein a second channel is obtained by utilizing the other side band. The paper indicates the reasons which led to the selection of this particular system and discusses at some length those matters which require agreement between the transmitting and receiving stations when single-side-band transmission is employed.
{"title":"A Short-Wave Single-Side-Band Radiotelephone System","authors":"A. A. Oswald","doi":"10.1109/JRPROC.1938.228178","DOIUrl":"https://doi.org/10.1109/JRPROC.1938.228178","url":null,"abstract":"There is described briefly a short-wave single-side-band system which has been developed for transoceanic radiotelephone service. The system involves the transmission of a reduced carrier or pilot frequency and is designed to include the testing of twin-channel operation wherein a second channel is obtained by utilizing the other side band. The paper indicates the reasons which led to the selection of this particular system and discusses at some length those matters which require agreement between the transmitting and receiving stations when single-side-band transmission is employed.","PeriodicalId":54574,"journal":{"name":"Proceedings of the Institute of Radio Engineers","volume":"56 1","pages":"1431-1454"},"PeriodicalIF":0.0,"publicationDate":"1938-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/JRPROC.1938.228178","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62307393","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 : 1938-12-01DOI: 10.1109/JRPROC.1938.228179
A. Roetken
A new radiotelephone receiver has been developed for the reception of reduced-carrier single-side-band signals in the frequency range from 4 to 22 megacycles. This receiver employs triple detection in which the first beating oscillator is continuously variable and the second is fixed in frequency. The first oscillator is a very stable tuned-circuit type, the proper adjustment of which is maintained through the use of an improved type of synchronizing automatic-tuning-control system. The second oscillator is crystal controlled. Separation of the carrier and side band is accomplished in the receiver by means of band-pass crystal filters which provide extremely high selectivity. Unusually high stability and selectivity characterize the performance of the receiver.
{"title":"A Single-Side-Band Receiver for Short-Wave Telephone Service","authors":"A. Roetken","doi":"10.1109/JRPROC.1938.228179","DOIUrl":"https://doi.org/10.1109/JRPROC.1938.228179","url":null,"abstract":"A new radiotelephone receiver has been developed for the reception of reduced-carrier single-side-band signals in the frequency range from 4 to 22 megacycles. This receiver employs triple detection in which the first beating oscillator is continuously variable and the second is fixed in frequency. The first oscillator is a very stable tuned-circuit type, the proper adjustment of which is maintained through the use of an improved type of synchronizing automatic-tuning-control system. The second oscillator is crystal controlled. Separation of the carrier and side band is accomplished in the receiver by means of band-pass crystal filters which provide extremely high selectivity. Unusually high stability and selectivity characterize the performance of the receiver.","PeriodicalId":54574,"journal":{"name":"Proceedings of the Institute of Radio Engineers","volume":"24 9 1","pages":"1455-1465"},"PeriodicalIF":0.0,"publicationDate":"1938-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/JRPROC.1938.228179","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62307426","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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