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Search Results: 1 - 10 of 140735 matches for " LI Zhong-Heng "
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Existence of black holes in Friedmann-Robertson-Walker universe dominated by dark energy
Zhong-Heng Li,Anzhong Wang
Mathematics , 2006, DOI: 10.1142/S0217732307024048
Abstract: We study the existence of black holes in a homogeneous and isotropic expanding Friedmann-Robertson-Walker (FRW) universe dominated by dark energy. We show that black holes can exist in such a universe by considering some specific McVittie solutions. Although these solutions violate all three energy conditions, the FRW background does satisfy the weak energy condition.
Quantum Corrects to the Entropy of the Barriola Vilenkin Black Hole Due to Spin Fields
自旋场对Barriola-Vilenkin黑洞熵的量子修正

LI Gu-Qiang,LI Zhong-Heng,
李固强
,黎忠恒

数学物理学报(A辑) , 2003,
Abstract: The quantum corrections to the entropy of the Barriola-Vilenkin black hole due to the gravitation electromagnetic and neutrino fields are calculated by using the brick-wall model. It is shown that the quantum corrects consist in two parts: One is aquadratic divergent term at event horizon and is proportional to the surface area of the event horizon. The other is two logarithmically divergent terms which not only depend on the characteristics of the black hole but also on the spin of fields. The whole expression does not take the form of the scalar field.
QUANTUM ERGOSPHERE EFFECT OF SPHERICALLY SYMMETRIC NON-STATIC BLACK HOLE
球对称动态黑洞的量子能层效应

LI ZHONG-HENG,MI LI-QIN,
黎忠恒
,米丽琴

物理学报 , 1999,
Abstract: By means of the Newman-Penrose formalism,the gravitational,electromagnetic, scalar and Dirac fields in spherically symmetric non-static space-times are discussed.It is shown that the quantum ergosphere can influence the radiative mechanism of a non-static black hole.The character of the effect is that the radiative mechanism is obviously dependent on the spin state,which differs from the classical effects due to the Kerr ergosphere and the electromagnetic potential.
Thermodynamical quantities around\\[1.8mm] a RNAdS black hole
Thermodynamical quantities around a RNAdS black hole

Mi Li-Qin,Li Zhong-Heng,
米丽琴
,黎忠恒

中国物理 B , 2006,
Abstract: The entropy density, energy density, pressure and equation of state around the RNAdS black hole are calculated in the WKB approximation on the Teukolsky-type master equation. The appearance of spin-dependent terms is demonstrated. The existence of these terms shows that the black hole radiation is not exactly thermal radiation and the black hole entropy is not strictly proportional to the area of the event horizon.
BOTH THE ENTROPY CHANGE AND THE TEMPERATURE OF BLACK HOLES ARE THE COMPENSATE EFFECT UNDER THE TIME-SCALE TRANSFORMATION
黑洞的温度和熵变化是时间尺度变换的补偿效应

ZHAO ZHENG,LI ZHONG-HENG,
赵峥
,黎忠恒

物理学报 , 1996,
Abstract: The compensate effect under the time-scale transformation for the Schwarzschild black hole and Vaidya black hole are studied. The gauge potential is the contraction of the affine connection. Both the Hawking temperature and the change of entropy of black holes can be regarded as the pure-gauge potentials of the compensate field.
THE GENERALIZED TORTOISE COORDINATE-TRANSFORMATION AND HAWKING PROCESSES
广义Tortoise坐标变换与Hawking过程

LI ZHONG-HENG,ZHAO ZHENG,
黎忠恒
,赵峥

物理学报 , 1997,
Abstract: By discussing on the dynamical equations of sorts of particles in the non-stationary Rindler and the Vaidya space-time,it is shown that after introducing new coordinates into a time-dependent metric,the method to define the tortoise coordinate transformation in a stationary space-time can be generalized to a non-stationary case.The character of the obtained tortoise transformation is that the temperature function is obviously dependent on time.It is also shown that the Hawking processes are independent of the source terms in the dynamical equations.Particularly,we find a picture where particle-scattering must be twice in the Hawking radiation described by the general time t such as in the non-stationary Rindler case.
Funnel-Shaped Arrays of Metal Nano-Cylinders for Nano-Focusing

ZHOU Xiu-Li,FU Yong-Qi,WANG Shi-Yong,PENG An-Jin,CAI Zhong-Heng,

中国物理快报 , 2008,
Abstract: We analyse funnel-shaped arrays of metal nanocylinders that can be potentially used as waveguides for nano-focusing of light. The proposed structures consist of Ag nanocylinders with gradually changed radii and discrete spacing arranged like side-view funnels with different angles. Finite-difference and time-domain simulations demonstrate that the proposed structures with different spacings and funnel angles have versatile light propagation characteristics. These structures can focus the incident Gaussian light beam (200nm at its full width at half maximum) into beam sizes of 10nm, 15nm, and 20nm, respectively, which corresponds to the transmission efficiencies of 38%, 40%, and 80%.
Study on the Dynamic Relationship between Puccinellia tenuiflora Biomass and Environmental Factors in Degraded Grasslands
退化草原碱茅的生物量与环境因子动态关系的研究

ZHANG Zhong-Heng,ZHANG Chong-Bang,LI Jian-Dong,
张忠恒
,张崇邦,李建东

植物学报 , 1999,
Abstract: In degraded grasslands, the growth of Puccinellia tenuiflora follows a seasonal variation pattern, with a maximum biomass in August (98.4 g/m2). Among the eight environment factors that directly and indirectly affect the growth of Puccinellia tenuiflora, hydrolysable nitrogen, effective phosphorus, quick-acting potassium, pH, water content and electric conductirity are the most important.
Survey on researches of UWB range extension applications
超宽带拓展距离应用的研究综述*

Zhao Liang,Chen Jin-yu,Huang Kai-zhi,Ji Zhong-heng,Jin Liang,
赵亮
,金梁,季中恒,黄开枝,陈金玉

计算机应用研究 , 2011,
Abstract: At present, UWB systems are mainly used for short distance applications. In order to extend the application field, some researches have been carried out on the range extension of UWB systems. Accordingly, a survey is made of these researches. The application scenarios of UWB long-distance communications are described, and based on the principle analysis, example demonstration and difficulty exploration, six strategies for the range extension of UWB communications are introduced, which are the reduction of the communication rate, the use of directional antennas, the use of MIMO antennas, the use of cooperative communication or multi-hop transmission, the use of multi-tap RAKE receiver, and the breakthrough of the power spectral density limit. The survey can serve as important reference for the implementation scheme selection of UWB long-distance communications.
Ultra-wideband wireless communication system based on Chirp-BOK-DQPSK modulation
基于Chirp-BOK-DQPSK调制的超宽带无线通信系统*

CHEN Jin-yu,ZHAO Liang,LIU Shuang-ping,LUO Xing-guo,JI Zhong-heng,
陈金玉
,赵亮,刘双平,罗兴国,季中恒

计算机应用研究 , 2011,
Abstract: In order to solve the low efficiency problem of Chirp-BOK modulation, this paper proposed UWB wireless communication system based on Chirp-BOK-DQPSK modulation. Analyzed and validated the BER performance in AWGN channel, and investigated the reason of inter-symbol interference in multipath channel. Simulation had been done to compare the performance of Chirp-BOK-DQPSK-UWB with Chirp-BOK-UWB and Chirp-BOK-DBPSK-UWB in IEEE 802.15SG4a CM1 and CM7 channel. The simulation results show that the system can efficiently improve the transmission rate with some reduction of the BER performance.
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