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Effect of Strong Magnetic Field on Gamow-Teller Transition Electron Capture of Iron Group Nuclei at Crusts of Neutron Stars

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Communications in Theoretical Physics 2008年第1期49卷 239-242页

作者： liu Jing-Jing luo Zhi-Quan Institute of Theoretical Physics China West Normal University Nanchong 637002 China

The electron capture of Gamow--Teller transition on iron group nuclei is investigated in a strong magnetic. field at the crusts of neutron stars. The results show that the magnetic field has only a slight effect on the electron capture rates with the range of the magnetic fields （10^9 - 10^13 G） on surfaces of most neutron stars, whereas for some magnetars whose range of the magnetic field is 10^13 - 10^18 G, the electron capture rates of most iron group nuclei would be debased greatly and may be even decreased overrun 3 orders of magnitude by the strong magnetic field.

关键词： strong magnetic field Gamow-Teller transition electron capture neutron star

Dynamic subcarrier and power allocation based on cooperative game theory in symmetric cooperative OFDMA networks

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The Journal of China Universities of Posts and Telecommunications 2011年第2期18卷 9-16页

作者： liu Wei luo Tao YUE Guang-xin Key Laboratory of Universal Wireless Communication Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

In order to improve the efficiency and fairness of radio resource utilization,a scheme of dynamic cooperative subcarrier and power allocation based on Nash bargaining solution（NBS-DCSPA） is proposed in the uplink of a three-node symmetric cooperative orthogonal frequency division multiple access（OFDMA） *** the proposed NBS-DCSPA scheme,resource allocation problem is formulated as a two-person subcarrier and power allocation bargaining game（SPABG） to maximize the system utility,under the constraints of each user＇s maximal power and minimal rate,while considering the fairness between the two ***,the equivalent direct channel gain of the relay link is introduced to decide the transmission mode of each ***,all subcarriers can be dynamically allocated to the two users in terms of their selected transmission *** that,the adaptive power allocation scheme combined with dynamic subcarrier allocation is optimized according to ***,computer simulation is conducted to show the efficiency and fairness performance of the proposed NBS-DCSPA scheme.

关键词： cooperative relay OFDMA radio resource allocation NBS fairness

Blue Generation in a Periodically Poled LiTaO3 by Frequency Tripling and 1342 nm ND:YVO4 Laser

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Chinese Physics Letters 2002年第7期19卷 944-946页

作者： He Jing-Liang, liu Jie, luo Guo-Zhen Laboratory of Modern Optics Shandong Normal University Ji\'nan 250014 National Laboratory of Solid State Microstructure Nanjing University Nanjing 210093

We report on an efficient blue light generation in periodically poled LiTaO3 by the frequency tripling of a quasi-continuous 1342 nm Nd:YVO4 laser. The period of the sample was 14.778 μm. Blue light with an average power of 138 mW was generated from a 18 mm long crystal in a single-pass process under an average fundamental power of 713 mW. The internal conversion efficiency was 19.3%.

关键词： Tantalum compounds

Mathematical Model of the Geothermal Water Resources in the South Hot Spring System in Chongqing

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Journal of China University of Geosciences 2005年第3期16卷 262-267页

作者： liu Dongyan luo Yunju liu Xinrong College of Civil Engineering Chongqing University Chongqing 400045 China

The geothermal waters of south hot spring, small hot spring and Qiaokouba in Chongqing, are all part of the south hot spring geothermal water system. Exploitation has caused a decline in the water levels of the south and small hot springs, which have not flowed naturally for 15 years. Now, bores pump geothermal water to the springs. If the water level drops below the elevation of the rivers, river-water will replenish the geothermal water, destroying this resource. It is therefore an urgent task to model the geothermal water system, to enable sustainable development and continued use of the geothermal water in Qiaokouba. A numerical simulation of the geothermal water system was adopted and a quantitative study on the planning scheme was carried out. A mathematical model was set up to simulate the whole geothermal water system, based on data from the research sites. The model determined the maximum sustainable water yield in Qiaokouba and the two hot springs, and the south hot spring and small hot spring sustainable yields are 1 100 m^3/d and 700 m^3/d from 2006 to 2010, 1 300 m^3/d and 1 000 m^3/d from 2011 to 2015, and 1 500 m^3/d and 1 200 m^3/d from 2016 to 2036. The maximum exploitable yield is 3 300 m^3/d from 2006 to 2036 in Qiaokouba. The model supplies a basis to adequately exploit and effectively protect the geothermal water resources, and to continue to develop the geothermal water as a tourist attraction in Chongqing.

关键词： south hot spring geothermal water system geothermal water resources mathematical model sustainable development yield

Processes and environmental significance of the subglacial chemical deposits in Tianshan Mountains

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Science China Earth Sciences 2005年第9期48卷 1470-1478页

作者： liu Gengnian luo Risheng CAO Jun CUI Zhijiu College of Environmental Sciences Peking University Beijing 100871 China College of Environmental Sciences Peking University Beijing 100871 China College of Environmental Sciences Peking University Beijing 100871 China College of Environmental Sciences Peking University Beijing 100871 China

On the bedrock surface of Glacier No.1 in the headwater of Urumqi River, Tianshan Mts., well layered and crystallized subglacial calcite precipitations were discovered. Based on observations and analysis of the surface form, sedimentary texture and structure, and chemical composition of the deposits, clues about the subglacial processes and environment are deduced. The radial-growth crustation texture of the deposits, which builds up in the saturated CaCO3 so- lution, proves the existence of pressure melting water and water films under Glacier No.1; and their rhythmic beddings, dissolved planes and unconformable contacts show that the water films responsible for the formation of these structures were in a wide range of spatial as well as tem- poral variations. Though formed under continental glacier in non-limestone area, the deposits are quite similar to those formed under temperate glaciers in limestone areas, a fact that shows a similar process of chemical precipitation between the two. Hence the enrichment of calcium in the subglacial melting water and the process of precipitation have actually little to do with the bedrock lithology and the glacier types. The cemented detritus in the deposits are rich in Fe and Al while depleted in K, Na and Si; also the included clay mineral consists mainly of illite, which reveals some weak chemical weathering under the continental glacier. The subglacial CaCO3 precipitates when plenty of Ca++ melt into the subglacial melting water on a comparatively en- closed ice-bedrock interface under a high CO2 partial pressure, the forming of subglacial chemical deposits therefore offers unequivocal evidence for the ongoing of subglacial chemical reactions.

关键词： subglacial processes, chemical deposits, continental glacier.

Magnetic Field Effect on β^＋ Decay in the Crusts of Accreting Neutron Stars

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Communications in Theoretical Physics 2007年第4期47卷 765-768页

作者： ZHANG Jie liu Men-Quan luo Zhi-Quan Institute of Physics and Electron Information China West Normal University Nanchong 637002 China

Based on shell model of nuclei, the influence of a high magnetic field on β^＋ decay in the crusts of accreting neutron stars is analyzed. The magnetic field effect on 54 Mn is discussed. The results show that a weak magnetic field makes little effect on β^＋ decay but a strong magnetic field （B 〉 10^11 G） improves β^＋ decay rates obviously. The conclusion derived will benefit to develop further research on nuclear astrophysics in the future.

关键词： β^+ decay strong magnetic field neutron star

SIMULATION OF SEDIMENT-LADEN FLOW BY DEPTH-AVERAGED MODEL BASED ON UNSTRUCTURED COLLOCATED GRID

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Journal of Hydrodynamics 2007年第4期19卷 525-532页

作者： liu Shi-he luo Qiu-shi MEI Jun-ya School of Water Resource and Hydropower Wuhan University Wuhan 430072 China

The 2-D depth-averaged mathematical model for sediment-laden flows has been widely used in river control and other related engineering problems, and now it is usually solved on structured grids. Since the natural river is usually very complicated in plane boundary, and unstructured grids are more attractive in solving the problems with complicated domains, the following questions about solving 2-D depth-averaged model were discussed in this article：（1） a modified Bowyer algorithm was suggested to generate unstructured grids for natural rivers, （2） the Finite Volume Method （FVM） is employed to discretize the governing equations of the 2-D depth-averaged model and an implicit scheme was suggested with unstructured collocated grids, （3） the observed hydrological data of the Chenglingji Reach in the Yangtze River are used for verification of the presented method It seems that the suggested numerical scheme works very well, and the simulation results of both hydraulic characteristics and river bed deformation are in good agreement with the observed ones.

关键词： Bowyer algorithm unstructured grid SIMPLE algorithm

Effect of Superstrong Magnetic Fields on Nuclear Energy Generation Rate in the Crust of Neutron Stars

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Communications in Theoretical Physics 2008年第4期49卷 1069-1072页

作者： liu Hong-Lin luo Zhi-Quan liu Jing-Jing LAI Xiang-Jun Institute of Theoretical Physics China West Normal University Nanchong 637002 China

This paper shows that superstrong magnetic fields （such as those of magnetars） can increase the energy generation rate many times in the crust of neutron stars. This result undoubtedly not only influences the coolin... 详细信息

关键词： superstrong magnetic fields energy generation rate neutron stars

AN ACCURATE PREDICTION MODEL FOR COMPUTATIONAL OVERHEADS OF SECURITY MECHANISMS IN WIRELESS SENSOR NETWORKS

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Journal of Electronics(China) 2009年第5期26卷 699-705页

作者： liu Wei luo Rong Yang Huazhong Department of Electronic Engineering Tsinghua University Beijing 100084 China

In Wireless Sensor Networks (WSNs), it is necessary to predict computational overheads of security mechanisms without final implementations to provide guidelines for system design. This paper presents an accurate and flexible model to predict overheads of these mechanisms. This model is based on overheads of basic operations frequently used in cryptography algorithms, which are essential elements of security mechanisms. Several popular cryptography algorithms and security mechanisms are evaluated using this model. According to simulation results, relative prediction errors are less than 7% for most cryptography algorithms and security mechanisms.

关键词： Wireless Sensor Network (WSN) Cryptography algorithm Security mechanism Computational overhead