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Simplified Method and Imp.o.ed Solution for Deriving Fifth order Stokes Wave

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China ocean Engineering 1997年第4期12卷 431-440页

作者： Fu Yuhua Senior Engineer, China offshore oil p.o.uction Research Center, p. o. box 9607, Beijing 100086 China offshore oil p.o.uction Research Center P. O. Box 9607 Beijing 100086 China

As the solution of the two equations for determining the existing fifth order Stokes wave derived by Skjelbreia is complex and tedious, the two equations are simplified into one equation for determining d / L, i. e., f(H, T, d / L) = 0. According to this simplified method, three cases of the solution for the Skjelbreia equations have been found: one accurate solution; more than one accurate solution and no accurate solution (but there exists the optimum app.o.imate solution in the area of satisfying Skjelbreia equations). As to the case of more than one accurate solution, the reasonable solution can be judged from the method of variational principle, by means elf which an optimum solution imp.o.ed from the solution of Skjelbreia equations in the area of satisfying the original mathematical equations of non-vortex and nonlinear wave theory, i. e., the optimum fifth order Stokes wave, is given.

关键词： fifth order Stokes wave simplified method variational principle imp.o.ed solution

The Active participation of ASIAA in the SMA p.o.ect

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天文研究与技术 1999年第S1期 11-17页

作者： Chi Yuan Institute of Astronomy and Astrophysics, Academia Sinica p.o. box 1-87, Nankang, Taipei, Taiwan, China

This is a p.o.ress report of a major p.o.ect that Institute of Astronomy & Astrophysics is actively engaged. The two 6m sub millimeter telescopes are being built in Taiwan. The construction of the antennas, which has been contracted to Aeronautic Research Laboratory, has made good p.o.ress lately. The first reflector is completed. The mounts are also nearly finished. The antennas are expected to be completed and tested in late 1999. our receiver lab has been built up from scratch. It is finishing the assembly of the first SMA receiver. It is also fabricating its first Nb Alo x Nb junction of 230 GHz. our two telescopes are scheduled to join the two SAo telescopes presently at Mauna Kea in the spring of year 2000.

关键词： The Active participation of ASIAA in the SMA p.o.ect SMA

A NUMERICAL RESEARCH oF NoNLINEAR BoDY-WAVE INTERACTIoNS

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Journal of Hydrodynamics 1991年第3期3卷 88-104页

作者： Zhou Zhen-quan Gu Mao-xiang, China Ship Scientific Research Center, p. o. box 116, Wuxi 214082, Jiangsu, p.R.China China Ship Scientific Research Cent Jiangsu China

This paper presents numerical research results of nonlinear body-wave interactions. The body-wave interac- tion is treated as a transient p.o.lem with known initial conditions. The development of the flow can be obtained by a time-stepping p.o.edure, in which the velocity potential of the flow at any instant is obtained by utilizing a source density distribution on all boundary surfaces. The orlanski's method is used to implement the boundary con- dition at the open boundary. The position of intersection points are determined by a direct method. The contents of this paper are: (1) A study of the nonlinear radiation p.o.lem of a floating body; (2) A study of nonlinear wave diffraction p.o.lem around large structures; (3) Interaction of nonlinear waves with a free floating body; (4) An attempt in generating a numerical wave tank. pretty good agreement is met between the numerical results and the analytical solution.

关键词： body A NUMERICAL RESEARCH oF NoNLINEAR BoDY-WAVE INTERACTIoNS BoDY

Blow up p.o.lem for Landau-Lifshitz equations in two dimensions

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Communications in Nonlinear Science and Numerical Simulation 2000年第1期5卷 43-44页

作者： Boling GUo Yongqian HAN and Ganshan YANG Institute of Applied physics and Computational Mathematics, Nonlinear Center for Studies, p. o. box 8009, Beijing 100088, China Graduate School of China Academy of Engineering physics, p. o. box 2101, Beijing 100 Inst. Appl. phys. and Compl. Math. Nonlinear Center for Studies P. O. Box 8009 Beijing 100088 China Graduate School of China Academy of Engineering Physics P. O. Box 2101 Beijing 100088 China

The solutions of two dimensional Landau-Lifshitz equations, which blow up in finite time, are obtained.

关键词： blow up two dimensional Landau-Lifshitz equations

Classification of highly turbid Jiaojiang Estuary

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Acta oceanologica Sinica 1998年第4期17卷 469-482页

作者： Dong Lixian (Second Institute of oceanography, State oceanic Administration, p. o. box 1207, Hangzhou 310012, China) Second Institute of oceanography State Oceanic Administration P. O. Box 1207 Hangzhou 310012 China

The Jiaoiang Estuary is shallow, macro-tidal dominated and extremely turbid, with a larger variation of the freshwater discharge. The estuarine stratification and classification are analysed by using a set of field data observed in wat *** spring tide, the depth-mean peak tidal currents can reach 2 m/s. During flood tide the water column is vertically hamogeneous, but the horizontal salinity gradient is large and there is a fresh water front. A 1 m thick fluid mud layer capped by lutocline is formed when the tidal current is less than 0. 3 m/s. As the low-salinity trapped in the fluid mud layer, underlying saltier water enhances vertical mixing when the fluid mud layer is eroded and the water column is only slishily stratified during ebb *** neap tide, the tidal currents are reduced, two lutoclines exist in the vertical p.o.ile of suspended sediment conentration (SSC ) for a long time and its positive contributions to the water column stability are 17 times larger than tha of maximum salinity gradient observed in our previous study. The water column is stratified and the fresh water front which exists in spring tide is lifted as a salt wedge in neap *** dynamics of the fine sediment is so important in the extremely turbid estuary that the estuarine classification does not fit in with the field data when the scheme of the estuarine classification p.o.osed by Schultz and Simons (1957) is applied in the Jiaoiang Estuary.

关键词： Estuary stratification mixing fine sediment,dynamics

Vacuum Fluctuations, Isolated Systems and Hierarchical Cosmology

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Journal of Systems Engineering and Electronics 1995年第4期6卷 285-298页

作者： p. F Browne (physics Department, UMIST, p. o. box 88, Manchester M601QD) physics Department UMIST P. O. Box 88 Manchester M60 1QD

Einstein's general theory of relativity rests on the convention of constant units for time and length, specified by standards at a fired world point p. It is valid to flatten space-time by choice of unit fields, obtained by applying time dilation and length contraction to standards in accordance with an aether velocity field vg(r,t). Two equally valid descriptions for gravitation result. Cosmology in flat space-time is first developed. Zero-point radiation is renormalized to finite energy Kpoc2 density by inclusion of gravitational self-potential energy density p.o.ided that Kpoc2 closes the uni- verse at radius R. It is shown that such a universe satisfies the black hole condition, and hence behaves as an isolated system. A single constant defines a finite universe with respect to any mass, due to self-adjustment of boundary surface. The equivalent Einstein model is found by a units transformation to be de Sitter space-time. Einstein's equations must contain only the cosmological term as source term. The Hubble redshift is shown to emerge in both Doppler-gravitational and frequency-decay guises. By postulating an infinite Cosmos containing universes on a hierarchy of scales specified by a geometric series of constants, it is possible for gravitation and electromagnetism to acquire equal complementary status. Unified field equations are p.o.osed, and the relationship between an electron and a universe is exp.o.ed. A theoretical value of the Hubble constant emerges, H= 108 km s-1Mpc-1.

关键词： General relativity Unified field Inertial force Hubble redshift.

Structure of Thunderstorm Gust Fronts with Topographic Effects

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Advances in Atmospheric Sciences 2001年第6期18卷 1161-1174页

作者： A. A. Bidokhti and T. Bani-Hashem Institute of Geophysics, Tehran University, p.o. box 14155-6466, Tehran, LR. Iran Tehran University Iran

Surface meteorological observations, associated with gust fronts p.o.uced by thunderstorm outflows over Tehran, an area surrounded by mountains, have been analyzed. Distinctive features are sudden drop in air temperature, up to 10°C, sharp increase in wind speed, up to 30 m s?1, with wind shift, to northwesterly, pressure jump, up to 4 hpa, humidity increase, up to 40%, and rain after some 20 min. Gust fronts which often occur in spring time, have a typical thickness of about 1.5 km and p.o.uce vertical wind shear of the order of 10?2s?1. Although these features seem to be common for most of the events, their intensities differ from one event to another, indicating that the gust fronts may occur in different sizes and shapes. Apart from a dominant effect on the formation of the original thunderstorms, topography appears to break up the frontal structure of the gust fronts. The internal Rossby radius of deformation for these flows is small enough (～ 100 km) for rotational effects to be minor. A laboratory model of the gust front (gravity current) also shows that it initially has a distinctive head with a turbulent wake, and can be broken up by topography. It is shown that when the environment is stratified, turbulence due to lobes and clefts instabilities near the nose of the current is suppressed. When the ground is rough, these instabilities are highly amplified and the internal Froude number of the flow is reduced. The bottom slope in the presence of rough topography leads to the break up.o. the current head and p.o.uces a broad and highly non-uniform head, recognized in the density signals. Key words Frontal structure - Gravity current - Meteorological data - outflows

关键词： Frontal structure Gravity current Meteorological data outflows

ACTIVE VIBRATIoN CoNTRoL oF FINITE L-SHApED BEAM WITH TRAVELLING WAVE App.o.CH

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Acta Mechanica Solida Sinica 2010年第5期23卷 377-385页

作者： Chunchuan Liu Fengming Li1 Wenhu Huang(p.o.box 137,School of Astronautics,Harbin Institute of Technology,Harbin 150001,China) [a] p.o. box 137 School of Astronautics Harbin Institute of Technology Harbin 150001 China

In this paper, the disturbance p.o.agation and active vibration control of a finite L-shaped beam axe studied. The dynamic response of the structure is obtained by the travelling wave app.o.ch. The active vibration suppression of the finite L-shaped beam is performed based on the structural vibration power flow. In the numerical calculation, the influences of the near field effect of the error sensor and the small error of the control forces on the control results are all considered. The simulation results indicate that the structural vibration response in the medium and high frequency regions can be effectively computed by the travelling wave method. The effect of the active control by controlling the power flow is much better than that by controlling the acceleration in some cases. And the control results by the power flow method are slightly affected by the locations of the error sensor and the small error of the control forces.

关键词： finite L-shaped beam active vibration control travelling wave app.o.ch power

EFFECT oF SHApE oN INCIpIENT MoTIoN oF SEDIMENT pARTICLES

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International Journal of Sediment Research 1999年第2期14卷 179-186页

作者： Zhao-Yin WANG Andreas DITTRICH ( International Research and Training Center on Erosion and Sedimentation, p.o. box 366, Beijing 100044. China Institute of Hydraulic Engineering and Rural Technology, Karlsruhe University 76128, Karlsruhe, Germany)

The effect of particle shape on the initiation of motion was studied experimentally with 11at. elliptical and round grains of the same volume-equivalent diameter. An armoring layer with imbricate cluster structure can be formed for flat particles. Experiments demonstrate that the particle shape has no great influence on the initiation of motion of individual particle before the imbricate cluster structure is developed. After the imbricate cluster structure is developed, however. the critical Shields parameter for initiation of flat particles is 65% larger than that for round particles. The influence of the length of the test section is studied in the paper too, which concluded that the influence is negligible as the length longer than 1 .4 m. Therefore the results of particles initiation with the 2 m long section is compatible to those from river flows.

关键词： particle shape Initiation of motion Imbricate cluster structure. Shields parameter