{"title":"Reflection of radio waves from undulating tropospheric layers","authors":"A. Waterman, J. Strohbehn","doi":"10.6028/JRES.067D.066","DOIUrl":"https://doi.org/10.6028/JRES.067D.066","url":null,"abstract":"","PeriodicalId":398550,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section D: Radio Propagation","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1963-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125623430","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}
The co ncep t of t he rm al stabili ty is utili zed to d eri ve expressions for t he radio refractivity of an a ir p a rcel und ergoing adiabatic compression or expansion. These expression s a re of exponen t ia l form witll scale heights of 12.5 km for t he dry adiabatic process and 7.0 km for the wet adiabatic process . The adiabatic curves for N are determined solely from conditions at the earth's surface. A new tu rb ulence p arameter, II , is d eri ved as t he di ffe rence of the en vironmen tal r efractive index struc t ure a nd t he adiabatic curves for a n a ir parcel li fted from t he s urface to 3 km. This parameter yields co rrelations wi t h three hou rl y median fi eld strength data t hat a rc not statistically differen t f rolTI those obtain ed with the much simpler para meter , toN. The co rrelations obtained wi th the eq ui valen t g radient are not statistically differen t from zero.
{"title":"A Radiometeorological Study, Part III. A New Turbulence Parameter","authors":"B. Bean, E. Dutton, J. Lane, W. B. Sweezy","doi":"10.6028/JRES.067D.065","DOIUrl":"https://doi.org/10.6028/JRES.067D.065","url":null,"abstract":"The co ncep t of t he rm al stabili ty is utili zed to d eri ve expressions for t he radio refractivity of an a ir p a rcel und ergoing adiabatic compression or expansion. These expression s a re of exponen t ia l form witll scale heights of 12.5 km for t he dry adiabatic process and 7.0 km for the wet adiabatic process . The adiabatic curves for N are determined solely from conditions at the earth's surface. A new tu rb ulence p arameter, II , is d eri ved as t he di ffe rence of the en vironmen tal r efractive index struc t ure a nd t he adiabatic curves for a n a ir parcel li fted from t he s urface to 3 km. This parameter yields co rrelations wi t h three hou rl y median fi eld strength data t hat a rc not statistically differen t f rolTI those obtain ed with the much simpler para meter , toN. The co rrelations obtained wi th the eq ui valen t g radient are not statistically differen t from zero.","PeriodicalId":398550,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section D: Radio Propagation","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1963-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114650784","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":"A radiometeorological study, part I. Existing radiometeorological parameters","authors":"J. Lane, B. Bean","doi":"10.6028/JRES.067D.063","DOIUrl":"https://doi.org/10.6028/JRES.067D.063","url":null,"abstract":"","PeriodicalId":398550,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section D: Radio Propagation","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1963-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128681816","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}
The groundwave pu lse has bee n co nsidered i n detail by Johler [1962, 1963b]. A t heory was presented as a d irect numer ical an d analyt ic evaluation ot the Fourier transform integral. S uch a t heory can be extended to treat pulsed ionospheric waves. The r efl ect ion process for various model a nistoropic ionospheres has been studied in detail in p revious papers by Johle r [1962] . The a nalys is of the reflec tion coefficient t hus demonstrated is employed to co nst ruct tran sfer fun ctions for the ionospheric wave. These t ra nsfer fun ctions a re t hen introduced into the Fo ur ier transform of the pulse, and the behav ior of LF pulses propagated by a refl ection process at t he ionosphere is determined for t hree mod els for the lower ionosphere. The co mposite ground a nd io nospheri c pulse is for med , a nd a method of tagging a po int-in. time on the pulse is detai led.
{"title":"Radio pulse propagation by a reflection process at the lower ionosphere","authors":"J. Johler","doi":"10.6028/JRES.067D.052","DOIUrl":"https://doi.org/10.6028/JRES.067D.052","url":null,"abstract":"The groundwave pu lse has bee n co nsidered i n detail by Johler [1962, 1963b]. A t heory was presented as a d irect numer ical an d analyt ic evaluation ot the Fourier transform integral. S uch a t heory can be extended to treat pulsed ionospheric waves. The r efl ect ion process for various model a nistoropic ionospheres has been studied in detail in p revious papers by Johle r [1962] . The a nalys is of the reflec tion coefficient t hus demonstrated is employed to co nst ruct tran sfer fun ctions for the ionospheric wave. These t ra nsfer fun ctions a re t hen introduced into the Fo ur ier transform of the pulse, and the behav ior of LF pulses propagated by a refl ection process at t he ionosphere is determined for t hree mod els for the lower ionosphere. The co mposite ground a nd io nospheri c pulse is for med , a nd a method of tagging a po int-in. time on the pulse is detai led.","PeriodicalId":398550,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section D: Radio Propagation","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1963-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129254232","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}
SUjwrclirl'ctil·it.v may be ach iC'vecl with sho rt VLF loop arrays bC'cause thl' bramlyidth d<'pcnds on l ~ ' upon the numbe r of loops and not the length of the ar ray. In a ddition the usual factors limiting s lIpel'dircctivity a rc not so prevall'l)' due to tl1(' (Ircoupl ing b('( I'rC' n Vr,F loops, Expressions al'l' deril'ed for thl' bcamwid th, ofl'l'otivl' hl'ight, J'('cl'ption patteI'll , ampli tude and pOsillon of the back lobes and the dfeets of loop voltage phasC' and amplituci!' ciirrrrrncrs brtwl'l'n loop". Thesl' eCjuat ions dl',;cr ibl' short a rra.vs of any nUl1lbr r of loop' ;. The most s('r ious lim itation on thl' directivity of supcrcli rl'ctive loop a rra.vs is t 11(' I'ollagc pha"l' ancl amplitudl' ciiffNe ncl's bC'lwee n loops. These cliffC' rl'nces bl'tw('rn adjacent loops add up to obse ul'(' tlw nulls anci dct('riorate tho reception pat terll.
{"title":"VLF superdirective loop array","authors":"E. Seeley","doi":"10.6028/JRES.067D.059","DOIUrl":"https://doi.org/10.6028/JRES.067D.059","url":null,"abstract":"SUjwrclirl'ctil·it.v may be ach iC'vecl with sho rt VLF loop arrays bC'cause thl' bramlyidth d<'pcnds on l ~ ' upon the numbe r of loops and not the length of the ar ray. In a ddition the usual factors limiting s lIpel'dircctivity a rc not so prevall'l)' due to tl1(' (Ircoupl ing b('( I'rC' n Vr,F loops, Expressions al'l' deril'ed for thl' bcamwid th, ofl'l'otivl' hl'ight, J'('cl'ption patteI'll , ampli tude and pOsillon of the back lobes and the dfeets of loop voltage phasC' and amplituci!' ciirrrrrncrs brtwl'l'n loop\". Thesl' eCjuat ions dl',;cr ibl' short a rra.vs of any nUl1lbr r of loop' ;. The most s('r ious lim itation on thl' directivity of supcrcli rl'ctive loop a rra.vs is t 11(' I'ollagc pha\"l' ancl amplitudl' ciiffNe ncl's bC'lwee n loops. These cliffC' rl'nces bl'tw('rn adjacent loops add up to obse ul'(' tlw nulls anci dct('riorate tho reception pat terll.","PeriodicalId":398550,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section D: Radio Propagation","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1963-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128878677","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}
A simple expressio n is d erived for the collisional detachment coeffi cient in tC' rms of prC'ssurl' , t empera t ure, a nd th e eleetron a ffinity, E a, of t he O, ion. By us ing t his ex pression , it is ra lculateci t ha t at night the pro file of elect ron dens ity against height ha s a max imum nca r thC' stratopa use at 50 kill . The magni t ude of t he electron de nsi ty at t he max imulll depend s cri t ica lly upo n H". If t he probabili ty of detachm ent app roache uni ty fo r Illolce ula l' e nergies exceed ing iSa , it may be dedu ced that E n mu st be at least greater t han 0.45 e' . SO Ill C co mments a re made o n the confl ict, in co ns id eri ng st ratospheri c ioni zat io n, between t hc co ncC'pts of ionospheri c ph ys ics a nd t hose of atmosp heri c electricity.
得到了碰撞分离系数的一个简单表达式，该表达式由p < s < s >、p < s < s >、p < s < s >和p < s < s > e < s < s >和p < s < s > e < e >的形式表示。通过这个表达式，我们可以计算出，在夜间，在50 kill时，候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选候选。当电子密度达到最大时，它的大小取决于它在H ' '上的临界值。如果在能量大于0.45的情况下，脱离的概率大于0.45，则可以推导出en必须至少大于0.45。所以生病了C公司mments使o n confl ict,在公司ns id eri ng圣ratospheri C ioni扎- io n t hc公司之间ncC 'pts ionospheri C的ph值y ics t软管大气heri C电。
{"title":"Collisional detachment and the formation of an ionospheric C region","authors":"E. Pierce","doi":"10.6028/JRES.067D.055","DOIUrl":"https://doi.org/10.6028/JRES.067D.055","url":null,"abstract":"A simple expressio n is d erived for the collisional detachment coeffi cient in tC' rms of prC'ssurl' , t empera t ure, a nd th e eleetron a ffinity, E a, of t he O, ion. By us ing t his ex pression , it is ra lculateci t ha t at night the pro file of elect ron dens ity against height ha s a max imum nca r thC' stratopa use at 50 kill . The magni t ude of t he electron de nsi ty at t he max imulll depend s cri t ica lly upo n H\". If t he probabili ty of detachm ent app roache uni ty fo r Illolce ula l' e nergies exceed ing iSa , it may be dedu ced that E n mu st be at least greater t han 0.45 e' . SO Ill C co mments a re made o n the confl ict, in co ns id eri ng st ratospheri c ioni zat io n, between t hc co ncC'pts of ionospheri c ph ys ics a nd t hose of atmosp heri c electricity.","PeriodicalId":398550,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section D: Radio Propagation","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1963-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125261991","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}
An ins trument, developed at NBS, has enabled continuous observations of VLF emiss ions. The continuous data has permitted the identifi cation of some new characterist ics of VLF emissions, and new information on the statistics of the occurrence of VLF e mission activity. The contin uous recordings are able to document the morphology of VLF emiss ion events and, therefore, acc ura tc correlations with other geophysical phenom ena are possible. Co rrelations of VLF em ission activity with abno rm al D-region absorption, X-ray events , and magnetic a ctiv ity are prcsented.
{"title":"Observations and results from the hiss recorder an instrument to continuously observe the VLF emissions","authors":"J. M. Watts, J. A. Koch, R. Gallet","doi":"10.6028/JRES.067D.061","DOIUrl":"https://doi.org/10.6028/JRES.067D.061","url":null,"abstract":"An ins trument, developed at NBS, has enabled continuous observations of VLF emiss ions. The continuous data has permitted the identifi cation of some new characterist ics of VLF emissions, and new information on the statistics of the occurrence of VLF e mission activity. The contin uous recordings are able to document the morphology of VLF emiss ion events and, therefore, acc ura tc correlations with other geophysical phenom ena are possible. Co rrelations of VLF em ission activity with abno rm al D-region absorption, X-ray events , and magnetic a ctiv ity are prcsented.","PeriodicalId":398550,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section D: Radio Propagation","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1963-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133493512","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}
General results and statistical studies of equatorial VHF oblique ionospheric scatter signals arc presented for one calendar year of t he International Geophysical Year. The equatorial scatter signals were usually stronger than their counterpart at temperate lati t udes. Scattering was observed comparable to t he D-region scatter propagation familiar elsewhere, but usually t he E-region scatter predominated. Scattering via F-region irregu larities was observed at nighttime over a 2580 km path centered about t he magnetic equator. The intense daytime equatorial E-regioll scattering was established to be largely due to irregularities associated with the equatorial electrojet. Its communications potentialities appear promising for patlls having midpoints within a 10° band of latitude centered about t he magnetic eq uator. When t he D-region scattering was distinguishable, it usually appeared to be stronger than t hat over similar paths at temperate latit udes. However, during the daytime over a path centered just at t he magnetic equator, this comparison is just the opposite. R.elatively st rong scattering from irregularities in the E region was also observed at n ighttime, with the result that the weakest signals received diurnally over the equatorial paths were comparable to the strongest signals propagated over similar paths at temperate latitudes. Both the daytime and nighttime scattering via E-region irregularities exhibited an asymmetry about the magnetic cquator, being stronger for a path midpoint 5° south of tbe magnetic equator tban for a midpoint a similar distance to t bc north.
{"title":"Ionospheric VHF scattering near the magnetic equator during the International Geophysical Year","authors":"R. Cohen, K. Bowles","doi":"10.6028/JRES.067D.051","DOIUrl":"https://doi.org/10.6028/JRES.067D.051","url":null,"abstract":"General results and statistical studies of equatorial VHF oblique ionospheric scatter signals arc presented for one calendar year of t he International Geophysical Year. The equatorial scatter signals were usually stronger than their counterpart at temperate lati t udes. Scattering was observed comparable to t he D-region scatter propagation familiar elsewhere, but usually t he E-region scatter predominated. Scattering via F-region irregu larities was observed at nighttime over a 2580 km path centered about t he magnetic equator. The intense daytime equatorial E-regioll scattering was established to be largely due to irregularities associated with the equatorial electrojet. Its communications potentialities appear promising for patlls having midpoints within a 10° band of latitude centered about t he magnetic eq uator. When t he D-region scattering was distinguishable, it usually appeared to be stronger than t hat over similar paths at temperate latit udes. However, during the daytime over a path centered just at t he magnetic equator, this comparison is just the opposite. R.elatively st rong scattering from irregularities in the E region was also observed at n ighttime, with the result that the weakest signals received diurnally over the equatorial paths were comparable to the strongest signals propagated over similar paths at temperate latitudes. Both the daytime and nighttime scattering via E-region irregularities exhibited an asymmetry about the magnetic cquator, being stronger for a path midpoint 5° south of tbe magnetic equator tban for a midpoint a similar distance to t bc north.","PeriodicalId":398550,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section D: Radio Propagation","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1963-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122448313","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}
The groundwave portion of atmospheric wavefor ms was examin ed to determine vario us characterist ics of the radiation field from li ghtn in g discha rges. Sixty-n ine representative waveforms were' selected from 1,029 atmospherics from 21 thunderstor ms in the Oklahoma and No rt h Texas area. The average ampli t ude and pha e spectra, from 1 kc/s to 100 kc/s, are presented for several groups of atmospherics hav ing distin guishable cha racteristics. Various relationships involving the total rad iated energy, peak fi eld strength, first half cycle length, spectral ampli tude peak and frequency of spectra peak are presented. The " normal" type of atmosplleric, composin g 86 percent of the total, is predominately of positive ini t ia l polarity, has a spectrum peak near 5 kc/s and has well defin ed relationships betwee n t he parameters mentioned above. All "other" types of atmospherics are predomin ately of negative initial polar ity, have a spectrum peak from less than 1 kc/ to 18 kc/s and have no well defined relationships between the various parameters.
{"title":"Radiation field characteristics of lightning discharges in the band 1 kc/s to 100 kc/s","authors":"W. L. Taylor","doi":"10.6028/JRES.067D.057","DOIUrl":"https://doi.org/10.6028/JRES.067D.057","url":null,"abstract":"The groundwave portion of atmospheric wavefor ms was examin ed to determine vario us characterist ics of the radiation field from li ghtn in g discha rges. Sixty-n ine representative waveforms were' selected from 1,029 atmospherics from 21 thunderstor ms in the Oklahoma and No rt h Texas area. The average ampli t ude and pha e spectra, from 1 kc/s to 100 kc/s, are presented for several groups of atmospherics hav ing distin guishable cha racteristics. Various relationships involving the total rad iated energy, peak fi eld strength, first half cycle length, spectral ampli tude peak and frequency of spectra peak are presented. The \" normal\" type of atmosplleric, composin g 86 percent of the total, is predominately of positive ini t ia l polarity, has a spectrum peak near 5 kc/s and has well defin ed relationships betwee n t he parameters mentioned above. All \"other\" types of atmospherics are predomin ately of negative initial polar ity, have a spectrum peak from less than 1 kc/ to 18 kc/s and have no well defined relationships between the various parameters.","PeriodicalId":398550,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section D: Radio Propagation","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1963-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115632521","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}
In the present paper we consider the problem of a horizontal magnetic dipole situated in or out of a lossy magnetoplasma halfspace when the magnetostatic field is parallel to the axis of the dipole. The rigorous formulation of the problem is carried to the point where the determination of the pertinent boundary coefficients remains to be a straightforward but not a simple algebraic process. Due to the prohibitive algebraic complexity involved in the explicit finding of the boundary coefficients, a high frequency approximation is intro duced and the approximate form of t he boundary coefficients fou nd. The field integrals are evaluated in t he air region for the condition when the observation point is at a large distance from the source. The results are applied to finding the radiation pattern in the air due to a magnetic dipole situated ncar t he lower edge of the ionosphere. It is found that the most important correction due to t he earth's magnetic field occu rs near the interface and parallel to t he axis of the dipole.
{"title":"Field of a horizontal magnetic dipole in the presence of a magnetoplasma halfspace","authors":"G. Tyras, A. Ishimaru, H. Swarm","doi":"10.6028/JRES.067D.053","DOIUrl":"https://doi.org/10.6028/JRES.067D.053","url":null,"abstract":"In the present paper we consider the problem of a horizontal magnetic dipole situated in or out of a lossy magnetoplasma halfspace when the magnetostatic field is parallel to the axis of the dipole. The rigorous formulation of the problem is carried to the point where the determination of the pertinent boundary coefficients remains to be a straightforward but not a simple algebraic process. Due to the prohibitive algebraic complexity involved in the explicit finding of the boundary coefficients, a high frequency approximation is intro duced and the approximate form of t he boundary coefficients fou nd. The field integrals are evaluated in t he air region for the condition when the observation point is at a large distance from the source. The results are applied to finding the radiation pattern in the air due to a magnetic dipole situated ncar t he lower edge of the ionosphere. It is found that the most important correction due to t he earth's magnetic field occu rs near the interface and parallel to t he axis of the dipole.","PeriodicalId":398550,"journal":{"name":"Journal of Research of the National Bureau of Standards, Section D: Radio Propagation","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1963-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122318359","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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