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1.
HIGHENERGYPHYSICSANDNUCLEARPHYSICSisascienceperiodicalfocusingonspecializedfieldswithitsfirstissuepublishedin 1 977.ItissponsoredbytheInstituteofHighEner gyPhysicsandtheInstituteofModernPhysics,theChineseAcademyofSciences.Itisamonthlyjournal,distributedbo…  相似文献   

2.
AStudyonYttriumContainingFullereneYC_(82)UsingLaserAblationMassSpectroscopy¥DONGGuoxuan;WANGShiliang;DAISongtao;LIChunming;CH...  相似文献   

3.
·LASERDEVICES·ExperimentalStudyonActive passiveMode lockingUsingCr4 + ∶YAGasSaturableAbsorber1 61 1AMicrochipTunableBlueLaserSourceBasedUponCr∶LiSAFinContactwithKNCrystal1 61 5HighPower 940nmAl freeActiveRegionLaserDiodesandBarswithaBroadWaveguide1 61 91 .3 2 μmNd3+ ∶Y…  相似文献   

4.
NEOCLASSICALTRANSPORTINATOKAMAKWITHELECTRICSHEARWANGZhong tian1,GLeClair2(1.SouthwesternInstituteofPhysics,Chengdu610041;2.CenterCanadiendeFusionMagnetique,Canada)  Abstract:Neoclassicaltransporttheoryforatokamakinthepresenceofalargeradialelectricfieldwithshea…  相似文献   

5.
G2PREDICTIONOFTHEENTHALPIESOFFORMATIONFORSOMEDIATOMICCATIONSANDNEUTRALSSuKeheDepartmentofChemicalEnginering,NorthwesternPoly...  相似文献   

6.
No .1BriefIntroductiontoHIGHENERGYPHYSICSANDNUCLEARPHYSICS (iii)…………………………………………IntroductiontoAuthors (v)……………………………………………………………………………………………………EditorialBoardofHIGHENERGYPHYSICSANDNUCLEARPHYSICS (vi)……………………………………………Letters FurtherAnalysisofDi gluonFusionMe…  相似文献   

7.
ASTATISTICALTHEORYFORTHEBIO-PHOTONEMISSIONOFTHELIVINGSYSTEMSPangXiaofengInternationalCentreforMaterialPhysics,AcademiaSinicaD...  相似文献   

8.
书评     
书评AIPHANDBOOKOFCONDENSERMICROPHONESTheorxCalibrationandMeasurementsGeergeS.K.Wong,TOnyF.W.Embleton主编321+XVll页(AmericanInstitu...  相似文献   

9.
拉曼光活性(ROA)经典理论模型研究马树国吴国祯(清华大学物理系北京100084)AClasicalTheoryfortheRamanOpticalActivityMaShuguo,WuGuozhen(DepartmentofPhysics,Tsin...  相似文献   

10.
THEORETICALCALCULATIONOFATOMICANDMOLECULARDATAPeiChunchuanPurpleMountainObservatoryAcademiaSinicaNanjing210008ABSTRACTByusin...  相似文献   

11.
When arranged in a nested-well configuration, plasma traps of the Penning/Malmberg type become potentially suitable for confining neutral plasmas. The nested-well configuration allows confinement of overlapping electron and ion plasmas. With an ion plasma overlapped by an equal-charge-density electron plasma, the ion density can exceed the severe ion density limit which occurs within traditional single-well plasma traps. With a nested-well configuration which is time dependent, overlapping electron and singly charged-ion plasmas can be confined at the same temperature. Possible uses of thermal neutral plasmas confined within time-dependent nested-well plasma traps include basic plasma science studies and plasma processing applications  相似文献   

12.
简要介绍了快重离子与固体相互作用研究的状况和快重离子引起固体电子发射的机制 ,讨论了电子能损导致原子位移的 3种微观模型 ,即“库仑爆炸”模型、“热峰”模型和“激发排斥”模型 ,简述了研究电子发射的实验测量装置和测量方法 ,讨论了总电子发射产额与电子能损的关系以及靶俄歇电子和快传输电子测量在电子激发诱发辐照损伤微观机制研究中的应用 ,并介绍了重离子在 C靶中产生的离子径迹处的电子温度和聚丙稀靶中离子径迹势的提取方法. The recent progresses in experimental and theoretical studies of the collision between swift heavy ion and solids as well as electron emission induced by swift heavy ion in solids were briefly reviewed. Three models, Coulomb explosion, thermal spike and repulsive long lived states, for interpreting the atomic displacements stimulated by the electronic energy loss were discussed. The experimental setup and methods for measuring the electron emission from solids were described ...  相似文献   

13.
We present new simulation studies exhibiting production of nonisothermal electron distributions and Langmuir waves by colliding ion holes and trapping of plasmons in an ion hole. We find that, during head-on ion hole collisions, streams of accelerated electrons are produced by the electrostatic potentials supporting the ion holes. Subsequently, Langmuir waves are excited by a two-stream instability involving energetic electron beams. The resulting Langmuir waves can be trapped in an ion hole. The present ion-hole-Langmuir wave interactions are unique kinetic phenomena which can be dealt with a Vlasov code, which we developed recently. The results can have relevance to the understanding of particle and field data that are forthcoming from different spacecraft missions in Earth's auroral ionosphere and the magnetosphere.  相似文献   

14.
《中国物理 B》2021,30(10):104103-104103
It is known that ion channel can effectively limit the radial expansion of an artificial electron beam during its longrange propagation in the space plasma environment. Most prior studies discussed the focusing characteristics of the beam in the ion channel, but the establishment process and transient properties of the ion channel itself, which also plays a crucial role during the propagation of the relativistic electron beam in the plasma environment, were commonly neglected. In this study, a series of two-dimensional(2 D) particle-in-cell simulations is performed and an analytical model of ion channel oscillation is constructed according to the single-particle motion. The results showed that when the beam density is higher than the density of plasma environment, ion channel can be established and always continues to oscillate periodically over the entire propagation. Multiple factors, including the beam electron density, initial beam radius, and the plasma density can affect the oscillation properties of ion channel. Axial velocity of the beam oscillates synchronously with the ion channel and this phenomenon will finally develop into a two-stream instability which can seriously affect the effective transport for relativistic electron beam. Choosing appropriate beam parameters based on various plasma environments may contribute to the improvement of the stability of ion channel. Additionally, radial expansion of the beam can be limited by ion channel and a stable long-range propagation in terrestrial atmosphere may be achieved.  相似文献   

15.
To store ions for times up to several seconds with energies in the 10 eV/amu range a tabletop storage ring with a circumference of about 1 m will be constructed. The ions will be confined and guided by RF-multipoles. The first objective is the production of pure ground state beams of (multiply charged) ions. This will allow for elucidating the unknown rule of metastable ions in electron capture studies, which will be performed in a crossed beam experiment after extraction of the ion beam from the storage ring. In order to test the technique of ion storage by means of RF-multipoles a linear RF-octopole beam guide has been constructed. First results of highly charged ion injection and subsequent electron capture studies in the RF-octopole beam guide are presented for C4+ ions.  相似文献   

16.
We report on optimization of electron transparent GaN based specimens for transmission electron microscopy (TEM) and scanning TEM (STEM) studies by combining focused ion beam thinning and low-energy (≤500 eV) Ar-ion milling. Energy dependent ion milling effects on GaN based structures are investigated and the quality of ion milled samples is compared with that of specimens prepared by wet chemical etching. Defects formed during ion milling lead to amorphization of the specimen. The experimental results are compared with Monte-Carlo simulations using the SRIM (stopping and range of ions in matter) software. Specimen thickness was deduced from high-angle annular dark field STEM images by normalization of measured intensities with respect to the intensity of the scanning electron probe and comparison with multislice simulations in the frozen lattice approach. The results show that the thickness of the amorphous surface layer can be successfully reduced below 1 nm by low energy ion milling, leading to a homogeneous image contrast in TEM and STEM, so that good conditions for quantitative analysis can be achieved. For an ion energy of 400 eV the thickness measurements resulted in an etching rate of about 6-8 nm/min.  相似文献   

17.
The suggestion of the existence of a photoassociative electron attachment process, X = e + hv → X?**, resulting in excited negative ion state formation is put forward, the energy necessary for the formation of such states being the sum of those of the photon and electron involved. The excited negative ion states can be detected by secondary electrons arising as a result of autodetachment and carrying away an energy well in excess of the incident electrons. The process concerned may provide the basis for a new type of unstable negative ion spectroscopy and constitutes a useful tool for obtaining atomic and molecular negative ions in a specific quantum state for spectroscopic studies.  相似文献   

18.
The time resolved studies on soft X-ray, hard X-ray, electron beam and ion beam emissions from a low energy plasma focus device are carried out simultaneously by employing a photodiode X-ray spectrometer, a scintillator photomultiplier tube, a combination of Faraday cup and Rogowski coil assembly and a biased Faraday cup, respectively. The soft X-ray is seen to be emitted in short multiple pulses corresponding to different pinch stages where as it is a single for hard X-ray, which corresponds to only maximum pinch stage. Similarly, multiple pulses of electron beam is found, which also corresponds to different pinch stages and these pulses are analogous with the soft X-ray pulses. The effective hard X-ray photon energy is estimated by foil absorption technique and found to be around 110 keV, which is consistent with the observed electron beam energy distribution. The simultaneous investigation of the electron and ion beam shows that both are accelerated by the same local field generated during the pinching process. The detailed results of time resolved studies on various radiations are incorporated in this Letter.  相似文献   

19.
20.
We present analytic and numerical calculations of the localized pinch model for ion collective acceleration by intense relativistic electron beams. These studies demonstrate the model's postulated synchronous acceleration of the ion clump and beam pinch. However, the configuration is found to be phase unstable, terminating the acceleration process before significant ion energy is acheived. Therefore, although the localized pinch model may be an appropriate explanation for some previous experimental observations of collectively accelerated MeV ions, it does not appear to be a suitable mechanism for high energy ion acceleration.  相似文献   

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