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  • 1
    Online Resource
    Online Resource
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2013
    In:  Acta Physica Sinica Vol. 62, No. 20 ( 2013), p. 208102-
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 62, No. 20 ( 2013), p. 208102-
    Type of Medium: Online Resource
    ISSN: 1000-3290
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2013
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  • 2
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 67, No. 17 ( 2018), p. 173201-
    Abstract: A systematical knowledge of the satellite and hypersatellite structures of X-ray transitions is of great interest for various research areas, such as the explanation of the X-ray radiation from universe, plasma diagnostics, extreme ultraviolet (EUV) and X-ray sources and so on. Among these researches, the detailed explanation of the complex structures of X-ray satellites and hypersatellites are crucial for understanding the X-ray emission mechanism and the hollow atom formation mechanism. In this paper, the Kα and Kβ X-ray satellite and hypersatellite structure are theoretically studied for hollow argon atoms with the relativistic multiconfiguration Dirac-Fock (MCDF) method, which includes the Breit and quantum electro-dynamics (QED) corrections. To check the applicability of the method, the transition energies and rates of the diagram lines for Ar are calculated,. and the results are in agreement with previously published data. Then the MCDF calculations of the transition energies and probabilities of Kα 1, 2 (K →L3, 2) and Kβ 1, 3 (K → M3, 2) X-ray satellites and hypersatellites, which originate from the argon atoms with additional vacancies in the L shell, are carried out. To obtain the overall profile of the K X-ray spectrum, the diagram lines are integrated with the satellites and hypersatellites on the assumption that the intensity is proportional to the corresponding transition probability and each discrete line has a Gaussian distribution profile with a full width at half maximum (FWHM) value of 20 eV. From the convoluted profile, we can obtain the dependence of the average transition energy and relative transition intensity of the satellites and hypersatellites on the initial hollow configuration. It is found that the transition energy shift increases linearly with the number of spectator vacancies in the L shell increasing. For instance, the energy shift of the Kα satellite caused by L-shell hole is about 20 eV, and that of the Kβ satellite is 48 eV. While for hypersatellite, the energy shift increases greatly due to the double ionization in the K shell. The energy shift increment of Kα and Kβ hypersatellites corresponding to L vacancy are 21 and 52 eV, respectively. Finally, four simple empirical formulae for estimating the energy shifts of the Kα, Kβ X-ray satellites and hypersatellite for Ar atom with any number of L-shells vacancies are deduced by using the least square method. These results are useful in explaining various K X-ray spectra and better understanding the collision process.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2018
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  • 3
    Online Resource
    Online Resource
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2014
    In:  Acta Physica Sinica Vol. 63, No. 14 ( 2014), p. 145205-
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 63, No. 14 ( 2014), p. 145205-
    Abstract: Vacuum arc ion sources have been used in a wide range including vacuum coating, materials surface modification, switching devices and other fields. At present, researches on the vacuum arc ion source are mainly targeting the pure metal or alloy electrodes, but the researches on the hydrogenous electrode are rarely reported. The axial and radial distributions of the hydrogenous electrode vacuum arc discharge plasma are studied by using high speed four-frame camera equipped with the narrow-band filters of strong lines of H I and Ti I. It is found that the anode is intensively luminous in the vacuum breakdown. The observation from the camera with the filter reveals that the vacuum breakdown is ignited mainly by the anode hydrogen desorption. The vacuum arc is sustained by plasmas emitted from either the cathode spots or the electrode inner wall. The cone-shaped cathode spot located at the cathode-insulator-vacuum junction is the main plasma source. It is found that the distribution of hydrogen atoms is much more homogeneous than that of titanium atoms, which may be due to the earlier beginning of hydrogen desorption, the bigger emitting area and faster diffusion speed of hydrogen atom.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2014
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  • 4
    Online Resource
    Online Resource
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2018
    In:  Acta Physica Sinica Vol. 67, No. 8 ( 2018), p. 084102-
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 67, No. 8 ( 2018), p. 084102-
    Abstract: China Academy of Engineering Physics terahertz free electron laser (CAEP THz FEL,CTFEL) is the first THz FEL oscillator in China,which is jointly built by CAEP,Peking University and Tsinghua University.It is designed as a high-repetition-rate and high-duty-cycle linac-based FEL facility. This THz FEL mainly consists of a gallium arsenide (GaAs) photocathode high-voltage direct current (DC) gun,a superconducting radio frequency (RF) linac,a planar undulator,and a quasi-concentric optical resonator. The DC gun provides a high-brightness electron beam with the bunch charge of about 100 pC and the repetition rate of 54.167~MHz.The normalized emittance of the electron beam is less than 10m,and the energy spread is less than 0.75%.A 24-cell superconducting RF accelerator provides an effective field gradient of about 10 MV/m and energizes the electron beam to 6-8~MeV.The beam then goes through the undulator and generates the spontaneous radiation,which is reflected back and forth in the optical resonator and then stimulated by the electron beam. The first stimulated saturation of CTFEL in the macro-pulse mode was obtained in August,2017.In this paper,the THz spectrum is measured by a Fourier spectrometer (Bruker VERTEX 80 V).The macro-pulse energy is measured by an absolute energy meter from Thomas Keating Instruments.The longitudinal beam length is preliminarily calculated by the auto-correlation curve from the time-domain signal of the spectrometer.The macro-pulse duration is captured by a GeGa cryogenic detector from QMC Instrument.The measurement results indicate that the terahertz laser frequency is continuously adjustable from 2 THz to 3 THz.The macro-pulse average power is more than 10 W and the micro-pulse power is more than 0.3 MW.The single-pass gain is larger than 2.5%. This facility is now working in macro-pulse mode in the first step,also called step one.The minimum macro-pulse duration is about 50s and the maximum is about 2 ms.The macro-pulse repetition is 1 Hz or 5 Hz.The typical pulse duration and repetition rate are 1 ms and 1 Hz,respectively.In the middle of 2018,the duty cycle will upgrade to more than 10% as step two.And the continuous wave (CW) operation will be obtained in step three by the end of 2018.The spectrum adjustment range will also be expanded to cover from 1 THz to 4 THz by then. Some application experiments have been carried out on the platform of CTFEL.This facility will greatly promote the development of THz science and its applications in material science,chemistry science,biomedicine science and many other cutting-edge areas in general.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2018
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  • 5
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 67, No. 5 ( 2018), p. 050701-
    Abstract: X-ray detector is a core component for X-ray astronomical observation and pulsar navigation.The on-orbit observation performance of X-ray detector will change gradually,owing to the influences of emission vibration,radiation damage of high-energy particles,and the aging of the components.The on-orbit calibration of X-ray detector facilitates the accurate acquisition and the precise modeling of X-ray radiation of the observation celestial bodies.In this paper a new method of calibrating the performance of X-ray detector is studied by using the radiation spectrum of the pulsar, which can effectively eliminate the influences from detector background and space environment noise.The on-orbit performance of the first focusing X-ray detector in China has been evaluated by analyzing the observations of the X-ray pulsar-based navigation satellite-1(XPNAV-1) for the Crab pulsar.The XPNAV-1 was launched in November 2016, with the aim of conducting the test of the feasibility of applying the regular emission of X-ray signals from pulsars to spacecraft navigation.Now,the first batch of scientific data about the Crab pulsar observations gained by the focusing X-ray detector for almost one month has been released.The pulse profiles of 124 observations and the total observational spectrum of Crab pulsar are achieved from those data.According to the international accurate X-ray radiation parameters of Crab pulsar,which have been determined by other X-ray space satellites,together with the absorption effect of the neutral hydrogen gas in the universe,the effective area of the focusing X-ray detector is estimated.The result shows that the effective area of the focusing X-ray detector on XPNAV-1 in an energy range of 0.6-1.9 keV is better than 2 cm2.The maximum effective area is 3.06 cm2 at an energy of 0.7 keV,which means that its detection efficiency is about 10%.As the observed energy increases,the effective area decreases.The area of the focusing X-ray detector in an energy range of 2-3.5 keV is about 1 cm2,and it is about 0.1 cm2 at energies above 5 keV,and its estimation accuracy is affected seriously by the statistical errors of X-ray photons.At the same time,another method of calibrating the effective area is studied by considering the energy response matrix of detector.The energy response matrix of the focusing X-ray detector is estimated by using the five ground test values of energy resolution.The effective area of the focusing X-ray detector is re-calibrated.However,the result shows that the energy response matrix exerts little effect on the effective area of the focusing X-ray detector.Finally,we suggest that the XPNAV-1 should observe some supernova remnants to monitor the changes of energy resolution and energy linearity and so on.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2018
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  • 6
    Online Resource
    Online Resource
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2004
    In:  Acta Physica Sinica Vol. 53, No. 7 ( 2004), p. 2244-
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 53, No. 7 ( 2004), p. 2244-
    Abstract: In the form of joint experiment between China and Russia, the experimental studies of Zpinches of mixed wire array of aluminum (A1) and tungsten (W) were carried out on S-300 generator,which was located on Kurchatov Institute of Russia. The experimental results were compared with those of single A1 array and single W array, respectively. There are obvious difference between mixed one and single one in their photon spectral distributions. The intensity of K-series emission lines from the mixed wire array Z-pinch is lower than that from single A1 array. The radiated lines with wavelengths less than 1.6nm were not found in single W array Z-pinches. In the Z-pinch processes, the area radiating x-arys in mixed wire array is smaller than that of single A1 array, but is larger than that of single W array. The radiated energy from mixed wire array Z-pinch is higher than that from single A1 array, but is slightly lower than that from single W array. The FWHM of x-ray pulse with a maximal power 0.3—0.5TW and total energy 10—20kJ is about 25ns, which radiated from Z-pinches with a radial convergence of 4—5 on S-300 generator. The shadow photograph of the mixed wire-array Z-pinch plasma by laser probe shows that the core-corona configuration was formed and the corona was moving toward the center axis during the wire-array plasma formation, that the interface of the plasma is not clear, and that therer are a number of structures inside. They also suggests that there was an obvious development of Magneto Rayleigh-Taylor instability in the Z-pinch process as well.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2004
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  • 7
    Online Resource
    Online Resource
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 2021
    In:  Acta Physica Sinica Vol. 70, No. 19 ( 2021), p. 197901-
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 70, No. 19 ( 2021), p. 197901-
    Abstract: As a novel low-cost semiconductor with extraordinary photoelectric property, the inorganic CsPb〈i〉X〈/i〉〈sub〉3〈/sub〉 perovskites have become emerging materials for the next generation of X-ray detectors in the past decade. However, most of recent studies of CsPb〈i〉X〈/i〉〈sub〉3〈/sub〉 perovskite X-ray detectors are based on their internal photoelectric effect. Though it is also important and widely used in vacuum X-ray detectors, the external photoelectric effect of CsPb〈i〉X〈/i〉〈sub〉3〈/sub〉 perovskite has been rarely studied by now. Thus, the response sensitivity of the CsPb〈i〉X〈/i〉〈sub〉3〈/sub〉 perovskite’s external photoelectric effect in the X-ray region is studied in the present paper. First, a 230-nm-thick CsPbI〈sub〉2〈/sub〉Br membrane is prepared on a metal substrate by a conventional one-step deposition method, with a precursor solution used. Then the external photoelectric responsivity and quantum efficiency of the CsPbI〈sub〉2〈/sub〉Br membrane are calibrated in a range from 2000 to 5500 eV at Beijing Synchrotron Radiation Facility. The responsivity is over 5.1 × 10〈sup〉–5〈/sup〉 A/W in the range and the quantum efficiency is over 23%. These calibration data are close to those of a traditional X-ray photoelectric material CsI. The Monte-Carlo method is utilized to simulate the external photoelectric effect of CsPbI〈sub〉2〈/sub〉Br perovskite, and the external photoelectric responsivity is calculated. The calculated data match well with the calibration, proving the Monte-Carlo method feasible for the external photoelectric effect simulation of CsPb〈i〉X〈/i〉〈sub〉3〈/sub〉 perovskite. Then the external photoelectric responsivities and quantum efficiencies of CsPb〈i〉X〈/i〉〈sub〉3〈/sub〉 perovskites are calculated via the Monte-Carlo method in the X-ray range from 2000 to 10000 eV. The calculated responsivities of different CsPb〈i〉X〈/i〉〈sub〉3〈/sub〉 perovskites are all close to the responsivity of CsI, and an order of magnitude higher than that of Au, and the CsPb〈i〉X〈/i〉〈sub〉3〈/sub〉 quantum efficiencies also follow a similar scenario. This indicates that CsPb〈i〉X〈/i〉〈sub〉3〈/sub〉 perovskites have good external photoelectric properties and potential applications in X-ray vacuum detectors such as photocathode and photomultiplier. The influence of thickness on CsPb〈i〉X〈/i〉〈sub〉3〈/sub〉 photoelectric response is also studied in this paper via Monte-Carlo simulation. The results show that the responsivity increases with the material thickness increasing, which is due to the increased X-ray absorption. The responsivities all reach their upper limits at a material thickness of about 150 nm, which means that the electrons generated at 150 nm can hardly escape from the material surface. It is indicated that the thickness of CsPb〈i〉X〈/i〉〈sub〉3〈/sub〉 should be no less than 150 nm to obtain the optimal photoelectric response.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2021
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  • 8
    Online Resource
    Online Resource
    Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences ; 1998
    In:  Acta Physica Sinica Vol. 47, No. 7 ( 1998), p. 1171-
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 47, No. 7 ( 1998), p. 1171-
    Abstract: The admittance spectroscopy technique has been used to study the hole confinement in Si/Si1-xGex/Si and boron highly doped superthin Si quantum wells. Based on the carrier thermal emission medel of the carriers in the well, the value of activation energy derived from the admittance spectra was considered as the distance from the position of the heavy hole ground state in the well to the top of it . For Si/Si1-xGex/Si quantum wells we found the value of activation energy increased with increasing annealing time at 800℃. The phenomena could be explained the annealing-induced interdiffusion of Si and Ge, the interface broadening, the weakening of quantum confinement, the decrease of the position of the heavy hole ground state, and so the increase of the activation energy. At the annealing temperature of 900℃, we only see the decrease of the value of activation energy with increasing annealing time. For boron highly doped superthin Si quantum wells due to quantum confinement effect, we observed the activation energy are different for samples with the same doping density but different well widths.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 1998
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  • 9
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 68, No. 11 ( 2019), p. 114207-
    Abstract: In recent years, the transmission capacity of wavelength division multiplexing (WDM) communication systems has gradually approached to the nonlinear Shannon limit. To meet the increasing demand for communication capacity, space division multiplexing (SDM) has become one of the most concerned technologies. In this paper, the four-wave mixing process (FWM) in fibers is considered from the frequency domain to the mode division multiplexing (MDM) spatial domain under pump depletion and the exact analytical solution to the FWM coupled-mode equations in the space-frequency domain is in detail deduced. The analytical method is verified by numerically calculating the amplitude and phase evolution of the idler wave in non-degenerate four-wave mixing. We discuss three new applications of the analytical solution as follows. 1) Using the phase matching condition we select the terms in the multi-wave coupling equation, and only retain the coupling term that plays a major role. According to the analytical solution in this paper, the phase matching percentage parameter is introduced to determine the FWM coupling terms necessary for multi-wave coupling equations, thus simplifying the multi-wave coupling problem in the study. 2) Combining the analytical solution with the numerical calculation results, we find the initial phase relationship between the output idler and the input guided wave for phase-insensitive FWM, and we provide the analytical expression for a theoretical basis to efficiently design the FWM-based phase arithmetic devices in parallel operating at WDM and MDM systems. 3) We propose a nonlinear compensation algorithm based on analytical solution, which can be used in the few-mode transmission system. The algorithm can fast evaluate or compensate for the fiber nonlinearity by taking into account the pump depletion of the FWM effect. Compared with the traditional digital back propagation (DBP) algorithm, our algorithm has the advantage of lower complexity.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2019
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  • 10
    In: Acta Physica Sinica, Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences, Vol. 61, No. 6 ( 2012), p. 066803-
    Abstract: The controlling technology of micro-structure on the surface of monocrystal silicon is a hot spot issue in semiconductor and solar cell fields because the conversion efficiency of monocrystal solar cell is affected by the structure of pyramid. With the traditional alkaline solution, monocrystal Si surface is easily textured, and becomes the surface full of the pyramid. However, it is difficult to control the sizes, the shapes and the distribution of pyramids in the process. In this paper, we discuss how a new additive influences the sizes, and the shapes of pyramids during the etching process. In experiment, silicon is etched in traditional alkaline solution with addition of the new additive at a fixed temperature and time. Samples are scanned by SEM. The SEM result shows that the samples are uniformly-densely filled with pyramids with smooth edges. The size of pyramid is smaller than that etched in the traditional alkaline solution. The etched surface is covered by pyramids with 24m in size. The reflectance spectrum of the textured surface is measured. The measured reflectance decreases to 12.51%. These experimental results show that the new additive can effectively cantrol the sizes and the distribution of pyramids on the silicon surface during the texturing process, which is very meaningful to control the textured structures of single crystal silicon surface.
    Type of Medium: Online Resource
    ISSN: 1000-3290 , 1000-3290
    Language: Unknown
    Publisher: Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences
    Publication Date: 2012
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