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The generators of Lorentz transformation in momentum space

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Science China Mathematics 2002年第2期45卷 241-245页

作者：张鹏飞阮图南 CCAST (World Lab.) P. O. Box 8730 Beijing 100080 China natl. synchrt. radiation laboratory Department of Modern Physics Univ. of Sci. and Technol. of China Hefei 230029 China

In the momentum space, the angular momentum operator and the boost vector operator,i.e. the generators for the Lorentz transformation of a particle with arbitrary spin and nonzero mass are discussed. Some new expressi... 详细信息

关键词： momentum space, angular momentum operator, boost vector operator.

Adsorption and Reaction of CO on Mo(100)-c(2×2)-N Surface Studied by HREELS

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Chinese Chemical Letters 2000年第3期11卷 275-278页

作者： Jun Fa ZHU.,ian Chang GUO, Run Sheng ZHAI, Xin He BAO, Shu Xian ZHUANG ( National Synchrotron radiation laboratory, University of Science and Technology of China, Hefei 230029 Department of Chemical Physics. University of Science and Technology of China natl. synchrt. radiation laboratory Univ. of Sci. and Technol. of China Hefei 230029 China State Key laboratory of Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China Department of Chemical Physics Univ. of Sci. and Technol. of China Hefei 230026 China

High resolution electron energy loss spectroscopy (HREELS) has been used to investigate the adsorption and reaction of CO on the Mo(100)-c(2×2)N surface. CO directly adsorbed on the N atoms from the c(2×2) layer to form isocyanate (NCO) surface species was found in addition to CO adsorbed on the molybdenum atoms at 120 K. indicating that both Mo and N atoms of the Mo(100)-c(2×2)-N surface are of high reactivities for CO adsorption.

关键词： HREELS adsorption reaction Mo(100)-c(2×2)-N CO.

WAVE EQUATION MODEL FOR SHIP WAVES IN BOUNDED SHALLOW WATER

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Journal of Hydrodynamics 2000年第4期12卷 109-119页

作者： T.S.Lee Mechanical & Production Engineering Department, National University of Singapore, Singapore 119620 Wu Jian kang, Xiong Chuan guang Mechanics Department of Huazhong University of Science & Technology, Wuhan 430074, P.R.China C.Shu Mechani Mech. and Production Eng. Dep. Natl. Univ. of Singapore Singapore 119620 Singapore

Ships were modelled as moving pressure disturbances on the free surface of a shallow water basin in the present paper. The moving pressure generating waves were subjected to the reflection of land boundaries and the radiation of open boundaries. This paper proposed and examined a wave equation model (WEM) to solve the shallow water equations with moving surface pressures simulating ship waves in a bounded shallow water region. The Galerkin finite element method was used to solve a second order wave equation for the free surface elevations and the hydrodynamic pressure of the ship bottom simultaneously. Horizontal velocities were obtained from the momentum equations. Numerical solutions of Series 60 C B=0.6 ships moving with the depth Froude number of F h= 0.6, 1.0, 1.3 in a rectangular shallow water harbor were investigated. Three dimensional surface elevation profiles and the depth averaged horizontal velocities were analysed. The numerical results characterised very well the ship waves in shallow water. Strong boundary reflection waves were found in the case of high depth Froude number (F h=1.3). Waves generated by the interactions of two ships moving in the same directions and in the opposite directions were also numerically investigated in the present study.

关键词： ship waves shallow water equations FEH

Summer Arctic sea fog

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Acta Oceanologica Sinica 2001年第2期20卷 183-196页

作者： Xie Simei, Xue Zhenhe, Jiang Dezhong, Zou Bin, Qu Shaohou (1. National Research Center for Marine Environment Forecasts, Beijing 100081, China 2. Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China) natl. Res. Ctr. for Marine Envrn. Fo Beijing 100081 China

Synchronous or quasi-synchronous sea-land-air observations were conducted using advanced sea ice, atmospheric and marine instruments during China's First Arctic Expedition. Expedition.Based on the Precious data from the expedition, it was found that in the Arctic Ocean, most part of which is covered with ice or is mixed with ice, various kinds of sea fog formed such as advection fog, radiation fog and vapor fog. Each kind he its own characteristic and mechanics of creation. In the southern part of the Arctic Ocean, due to the sufficient warm and wet flow there, it is favorable for advection fog to form, which is dense and lasts a long time. On ice cap or vast floating ice, due to the strong radiation cooling effect, stable radiating fog is likely to form. In floating ice area there forms vapor fog with the appearance of masses of vapor from a boiling pot, which is different from short-lasting land fog. The study indicates that the reason why there are many kinds of sea fog form in the Arctic Ocean is because of the complicated cushion and the consequent sea-air interaction caused by the sea ice distribution and its unique physical characteristics. Sea fog is the atmospheric phenomenon of sea-air heat exchange. Especially, due to the high albedo of ice and snow surface, it is diffcult to absorb great amount of solar radiation during the polar days. Besides, ice is a poor conductor of heat; it blocks the sea-air heat exchange. The sea-air exchange is active in floating ice area where the ice is broken. The sea sends heat to the atmosphere in form of latent heat; vapor fog is a way of sea-air heat exchange influencing the climate and an indicator of the extent of the exchange. The study also indicates that the sea also transports heat to the atmosophere in form of sensible heat when vapor fog occurs.

关键词： Arctic sea fog vapor fog radiation fog advection fog mechanism of the creation of sea fog

Research on Special Optical Fiber under radiation

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High Technology Letters 1999年第2期5卷 13-15页

作者：殷宗敏 natl. Lab. on Local Fiber-optic Commun. Netowrks and Advanced Optical Commun. Systems Institute of Optical Fiber Technology Shanghai Jiaotong University Shanghai 200030 China

The variation of optical spectrum of some special fibers under radiation is studied in this paper. We discuss the loss of optical fiber under the influence of radiation. It shown that the colourated positive ions in the silica fiber core is harmful(i.e. Fe, Cr, Mn, Cu, Co, Ni). In the visible band and near area(0.35μm～0.85μm), the spectral distribution of the common silica fiber is dependent on the radiation total dose and spectral curves of the particular double clad optical fiber is unchanged after the radiation.

关键词： Optical fiber radiation Loss

Calibration and brightness temperature algorithm of CE-1 Lunar Microwave Sounder (CELMS)

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Science China Earth Sciences 2010年第9期53卷 1392-1406页

作者： ZhenZhan Wang Yun Li XiaoHui Zhang Jiang JingShan ChuanDong Xu DeHai Zhang WeiGuo Zhang Chinese Acad Sci Natl Microwave Remote Sensing Lab Ctr Space Sci & Appl Res Beijing 100190 Peoples R China

CE-1 Lunar Microwave Sounder (CELMS) is the first passive microwave radiometer in the world to sound the surface of the Moon in the lunar orbit at altitude of 200 km. The scientific objective of CELMS is to obtain global brightness temperature (TB) of the Moon, to retrieve information on lunar regolith, and to evaluate the distribution of helium-3 on the Moon implanted by solar wind. Before launch of CELMS, a series of experiments were carried out in laboratories to test the performances of the systems, and to calibrate the responses between the input of TB and the output of voltage from the receivers. However, the thermal condition exposed to CELMS is more complicated in lunar orbit than on the Earth, which makes the temperatures of different parts of CELMS wave vary greatly, and the cosmic background is not very clean due to the pointing of cold space antenna to the direction of the satellite running, which brings uncertainties into data-processing of CELMS when the temperature of cold space is used as a calibrator. Furthermore, the lack of knowledge on the lunar ingredients and compositions, distributions of physical temperatures, and properties on lunar microwave radiation leads to difficulties in validating the measurements and retrievals of CELMS. By analyzing the results of ground experiments and the measurements of CELMS in-orbit, along with our knowledge of the properties of lunar surface, here we give algorithms on calibration and antenna pattern correction (APC) of CELMS. We also describe in detail the principle of microwave transfer among the elements of CELMS, and discuss the method on testing calibration parameters of the system. In addition, the theory and model on correction antenna pattern of CELMS are developed by comparing antenna temperatures by CELMS with those simulated by microwave radiative transfer models. The global distribution of TB is given and the features of TB are analyzed. Our results show rich information included in TB on the properties of lunar regolith, especially the thicknes

关键词： CE-1 CE-1 Lunar Microwave Sounder/CELMS in-orbit calibration cold space APC algorithm

Soft X-ray in-line holographic experiment

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Chinese Science Bulletin 1998年第8期43卷 641-643页

作者： Shaoguang Yang Xingshu Xie Chengzhi Jia Yongfei Zhao Shiping Jiang Yuxuan Zhang Xiaobin Shan Xinyi Zhang Univ Sci & Technol China Ctr Fundamental Phys Hefei 230026 Peoples R China Univ Sci & Technol China Natl Synchrotron Radiat Lab Hefei 230029 Peoples R China

Water window" soft X-ray has some advantages in the microimaging of biological specimens. Soft X-ray holography can give us three-dimensional images of biological cells in their natural condition. Quasi-monochromatic soft X-ray from the polymonochromatic synchrotron radiation is obtained by a zone plate-pinhole linear monochromator at National Synchrotron radiation laboratory (NSRL) at Hefei. The pinhole is used to increase the temporal coherence of the soft X-ray, and also to increase the spatial coherence of it. An in-line holographic experiment has been finished with soft X-ray of main wavelength 4.5 nm and pinhole of diameter 0.03 mm. The magnified hologram is reconstructed with He-Ne laser. A smaller pinhole is wanted to be used to improve the coherence of the soft X-ray so as to improve the quality of the hologram.

关键词： soft X-ray microscopy in-line hologram.

Effects of 4DVAR with multifold observed data on the typhoon track forecast

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Chinese Science Bulletin 2003年第S2期48卷 93-98页

作者： WANG Yunfeng, WANG Bin, MA GANG & WANG Yushun 1. LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences. Beijing 100029, China: 2. National Satellite Meteorological Center, Beijing 100081. China Chinese Acad Sci Inst Atmospher Phys LASG Beijing 100029 Peoples R China natl.Satellite Meteorol Ctr Beijing 100081 Peoples R China

Effects of 4-dimension variational data assimi-lation (4DVAR) with multifold observed data on the typhoontrack forecast are studied, by using the MM5V3 model, theRTTOVS-5 model and their adjoint models. The data usedfor assimilation include large-scale background fields data,bogus data, cloud-derived wind data, satellite inverse data,and high resolution infrared radiation sounder data (HIRS).There are 5 typhoon cases are used to perform the numericalexperiments and assimilation experiments. The numericalresults show that with 4DVAR the initial fields can be greatlyimproved and the initial typhoon structure can be clearlydescribed.

关键词： multifold observed data 4DVAR typhoon track. DOI: 10.1360/03wd0456

Synchrotron radiation photoemission study on growth of gadolinium film over Ni(110)surface

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Chinese Science Bulletin 1999年第4期44卷 328-331页

作者： Faqiang Xu Junfa Zhu Yuming Sun Xianfeng Wang Erdong Lu Pengshou Xu Xinyi Zhang Shuxian Zhuang Univ Sci & Technol China Natl Synchrotron Radiat Lab Hefei 230029 Peoples R China Univ Sci & Technol China Dept Chem Phys Hefei 230029 Peoples R China

The growth of Gd film on Ni(110) surfaco was studied by synchrotron radiation photoemission spectroscopy and XPS techniques. It is revealed that in the coverage range of 0—0.22 nm Gd4f core level showed a single-peak structure, therefore Gd film grows over Ni(110) in the layer-by-layer mode. However, when Gd coverage was larger than 0.22, nm the Gd4f peak turned gradually into double-peak and a double-peak structure with 2.3 eV separation was formed at 1.51 nm, meanwhile similar phenomenon was observed in the Gd4d XPS spectra. It is suggested that the double-peak structure of Gd4f was derived from the growth of Gd film in cluster mode and the Gd atomic clusters may exhibit different electronic states from Gd metal owing to their special structures. The Gd4f double-peak evolved into a single-peak on annealing at 600 K, implying that Gd clusters are thermodynamically unstable.

关键词： Gd film synchrotron radiation Ni(110) surface.