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Some characteristics of the atmosphere during an adiabatic process

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Progress in Natural Science:Materials International 2006年第6期16卷 644-648页

作者： GAO Li, LI Jianping and REN Hongli (LASG, institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china Graduate School of chinese academy of sciences, beijing 100049, china National Climate Center, Laboratory of Climate Studies, china Meteorological Administration, beijing 100081, china) LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate School of chinese academy of sciences Beijing 100049 China National Climate Center Laboratory of Climatic Studies China Meterological Administration Beijing 100081 China

Some important characteristics of the atmosphere during an adiabatic process are investigated, which include the invariability of atmospheric entropy range and local surface potential temperature, the conservation of the atmospheric mass intervened between any isentropic surface and the ground, and the isentropic surface intersecting with the ground. The analysis shows that the atmospheric reference state (ARS) for investigation on available potential energy (APE) should be defined objectively as the state which could be approached from the existing atmosphere by adiabatic adjustment, and be related to initial atmospheric state before adjustment. For the initial atmosphere state at any time, its corresponding ARS is different from the one at another time. Based on the above-mentioned conclusions, the reference state proposed by Lorenz cannot be obtained physically, so a new conception, the conditional minimum total potential energy, is put forward in order to objectively investigate atmospheric APE.

关键词： available potential energy adiabatic isentropic surface atmospheric reference state conditional minimum total potential energy.

Single-molecule studies of DNA by molecular combing

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Progress in Natural Science:Materials International 2007年第5期17卷 493-499页

作者： Liu Yuying, Wang Pengye and Dou Shuoxing (College of Science, china Agricultural University, beijing 100083, china Laboratory of Soft Matter physics, beijing National Laboratory for Condensed Matter physics, institute of physics, chinese academy of sciences, beijing 100080, china) College of sciences China Agricultural University Beijing 100083 China Laboratory of Soft Matter physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China beijing National Laboratory for Condensed Matter physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

Molecular combing is a powerful method for aligning a large array of DMA molecules onto a surface. It is a process whereby DNA molecules are stretched and aligned on a glass surface by the force via fluid flow. The ability to comb up to several hundred DNAs on a single cover slip allows for a statistically significant number of measurements to be made. These features make molecular combing an attractive tool for genomic studies, such as DNA replication, DNA transcription, DNA-protein interaction and so on. In this review article, we discuss the molecular combing principle, method and its applications.

关键词： DNA molecule molecular combing DNA-protein interaction.

Effects of zonal perturbations of sea surface temperature on tropical equilibrium states:A cloud-resolving modeling study

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Progress in Natural Science:Materials International 2008年第4期18卷 413-419页

作者： Xiaopeng Cui , Shouting Gao Laboratory of Cloud-Precipitation physics and Severe Storms, institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china Laboratory of Cloud-Precipitation physics and Severe Storms Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The effects of zonal perturbations of sea surface temperature (SST) on tropical equilibrium states are investigated based on a series of two-dimensional cloud-resolving simulations with imposed zero vertical velocity, constant zonal wind, and a zonal model domain of 768 km. Four experiments with zonal SST perturbations of wavenumbers 1 (C1), 2 (C2), 4 (C3), and 8 (C4) are compared to a control experiment with zonally uniform SST (C0). The 40-day integrations show that the temperatures reach quasi-equilibrium states with dis- tinct differences. C1 and C2 produce warmer equilibrium states whereas C3 and C4 generate colder equilibrium states than C0 does. The heat budgets in the five experiments are analyzed. Compared to C0, less IR cooling over smaller clear-sky regions in C1 and more con- densational heating in C2 are responsible for warmer equilibrium states. A reduced condensational heating leads to the cold equilibrium state in C3. The interaction between convective systems in C4 causes a decrease of condensational heating, which accounts for the cold equilibrium state.

关键词： Tropical equilibrium states Sea surface temperature Zonal perturbation Cloud-resolving modeling study

Development and improvement of mass flux convection parameterization scheme and its applications in the seasonal climate predication model

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chinese Science Bulletin 2003年第10期48卷 1006-1015页

作者： PING Fan, GAO Shouting & WANG Huijun institute of Atmosphere physics, chinese academy of sciences, beijing 100029, china institute of Atmosphere physics Chinese Academy of Sciences Beijing 100029 China

The features of Gregory cumulus parameterization scheme, which is used in British Weather Office, are researched and then this scheme is developed and improved according to the characteristics of area precipitation over china. Firstly, the influence of the large-scale convergence in lower tropopause upon cumulus convection is directly taken into account in a 揵ulk?cloud model. The organized entrainment and detrainment is considered in the model. Secondly, the initial mass flux is revised. Thirdly, the effects of subcooling water upon saturation vapour pressure are considered. Eventually, the drown-draft air is regulated. For several years, the numerical forecast of seasonal precipitation in china has been carried out by using the modified Gregory scheme. The result shows that the model with improved Gregory scheme well simulates the precipitation over china and the prediction result is good.

关键词：质量流量对流参数化季侯风应用大规模收敛对流层

Systematic distortion in cosmic microwave background maps

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Science china(physics,Mechanics & Astronomy) 2009年第5期52卷 804-808页

作者： LIU Hao 1,3 &LI TiPei 1,2 1Key Laboratory of Particle Astrophysics,institute of High Energy physics,chinese academy of sciences,beijing 100049,china 2Center for Astrophysics,Tsinghua University,beijing 100084,china 3 Graduate University of chinese academy of sciences,beijing 100049,china Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China Center for Astrophysics Tsinghua University Beijing China

To minimize instrumentally the induced systematic errors,cosmic microwave background(CMB)anisotropy experiments measure temperature differences across the sky using pairs of horn antennas, temperature map is recovered from temperature difference obtained in sky survey through a map-making *** inspect and calibrate residual systematic errors in the recovered temperature maps is important as most previous studies of cosmology are based on these *** analyzing pixel-ring coupling and latitude dependence of CMB temperatures,we find notable systematic devia- tion from CMB Gaussianity in released Wilkinson Microwave Anisotropy Probe(WMAP)*** detected deviation cannot be explained by the best-fit LCDM cosmological model at a confidence level above 99%and cannot be ignored for a precision cosmology study.

关键词： cosmology cosmic microwave background methods data analysis

Algebraically explicit analytical solu-tions for the unsteady non-Newtonian swirling flow in an annular pipe

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Science china(physics,Mechanics & Astronomy) 2006年第4期49卷 396-400页

作者： CAI Ruixian1 & GOU Chenhua1,2 1. institute of Engineering Thermophysics, chinese academy of sciences, beijing 100080, china 2. Graduate School, chinese academy of sciences, beijing 100080, china institute of Engineering Thermophysics Chinese Academy of Sciences Beijing China Graduate School Chinese Academy of Sciences Beijing China

This paper presents two algebraically explicit analytical solutions for the incompressible unsteady rotational flow of Oldroyd-B type in an annular pipe. The first solution is derived with the common method of separation of variables. The second one is deduced with the method of separation of variables with addition developed in recent years. The first analytical solution is of clear physical meaning and both of them are fairly simple and valuable for the newly developing computational fluid dynamics. They can be used as the benchmark solutions to verify the applicability of the existing numerical computational methods and to inspire new differencing schemes, grid generation ways, etc. Moreover, a steady solution for the generalized second grade rheologic fluid flow is also presented. The correctness of these solutions can be easily proven by substituting them into the original governing equation.

关键词： analytical solution, Oldroyd-B type fluid, swirling flow, non-Newtonian.

Concatenating construction of the multisymplectic schemes for 2+1-dimensional sine-Gordon equation

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Science china Mathematics 2004年第1期47卷 18-30页

作者： WANG Yushun, WANG Bin & QIN MengzhaoLASG, institute of Atmospheric physics, chinese academy of sciences, beijing 100029, china School of Mathematics and Computer Science, Nanjing Normal University, Nanjing 210097, china School of Mathematics and System Science, chinese academy of sciences, beijing 100080, china LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China School of Mathematics and Computer Science Nanjing Normal University Nanjing China School of Mathematics and System Science Chinese Academy of Sciences Beijing China

In this paper, taking the 2+1-dimensional sine-Gordon equation as an example, we present the concatenating method to construct the multisymplectic schemes. The method is to discretizee independently the PDEs in different directions with symplectic schemes, so that the multisymplectic schemes can be constructed by concatenating those symplectic schemes. By this method, we can construct multisymplectic schemes, including some widely used schemes with an accuracy of any order. The numerical simulation on the collisions of solitons are also proposed to illustrate the efficiency of the multisymplectic schemes.

关键词： 2+l-climensional sine-Gordon equation multisymplectic scheme concatenating method solitons

Properties of the 3/2^-[521] band in the odd-N rare-earth nuclei

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Science china(physics,Mechanics & Astronomy) 2011年第S1期54卷 37-43页

作者： CHEN Liang1,2, ZHOU XiaoHong1,2, ZHANG YuHu1, ZHANG ShuangQuan3 & ZHU LiHua4 1institute of Modern physics, chinese academy of sciences, Lanzhou 730000, china 2Graduate University of chinese academy of sciences, beijing 100049, china 3State Key Laboratory of Nuclear physics and Technology, School of physics, Peking University, beijing 100871, china 4china institute of Atomic Energy, beijing 102413, china institute of Modern physics Chinese Academy of Sciences Lanzhou China Graduate University of chinese academy of sciences Beijing China State Key Laboratory of Nuclear physics and Technology School of Physics Peking University Beijing China china institute of Atomic Energy Beijing China

High-spin states in 161Er have been studied experimentally via the 150Nd(16O, 5n) reaction at a beam energy of 86 MeV. Three rotational bands built on the 5/2+[642], 3/2-[521], and 11/2-[505] configurations have been extended up to high-spin states, and particularly, the α = -1/2 branch of the ground state 3/2-[521] band has been revised significantly. It is found that signature inversion occurs in the 3/2-[521] band after the band crossing in 161Er. The systematics of the signature inversion associated with the 3/2-[521] configuration in the rare-earth region is discussed. The band properties are analyzed within the framework of a triaxial particle-rotor model, and a triaxial deformation is proposed to the 3/2-[521] band.

关键词： high-spin states signature inversion triaxial particle-rotor model

Glassy metallic plastics

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Science china(physics,Mechanics & Astronomy) 2010年第3期53卷 409-414页

作者： LI JianFu, WANG JunQiang, LIU XiaoFeng, ZHAO Kun, ZHANG Bo, BAI HaiYang, PAN MingXiang & WANG WeiHua institute of physics, chinese academy of sciences, beijing 100190, china institute of physics Chinese Academy of Sciences Beijing China

This paper reports a class of bulk metallic glass including Ce-, LaCe-, CaLi-, Yb-, and Sr-based metallic glasses, which are regarded as glassy metallic plastics because they combine some unique properties of both plastics and metallic alloys. These glassy metallic plastics have very low glass transition temperature (Tg^25oC to 150oC) and low Young’s modulus (~20 GPa to 35 GPa). Similar to glassy plastics, these metallic plastics show excellent plastic-like deformability on macro-, micro- and even nano-scale in their supercooled liquid range and can be processed, such as elongated, compressed, bent, and imprinted at low temperatures, in hot water for instance. Under ambient conditions, they display such metallic properties as high thermal and electric conductivities and excellent mechanical properties and other unique properties. The metallic plastics have potential applications and are also a model system for studying issues in glass physics.

关键词： glassy metallic plastic synthesizing low Tg thermoplastic properties