19 resultados para 0105 Mathematical Physics
em Chinese Academy of Sciences Institutional Repositories Grid Portal
Resumo:
In this paper the authors prove that the generalized positive p selfadjoint (GPpS) operators in Banach space satisfy the generalized Schwarz inequality, solve the maximal dissipative extension representation of p dissipative operators in Banach space by using the inequality and introducing the generalized indefinite inner product (GIIP) space, and apply the result to a certain type of Schrodinger operator.
Resumo:
Ordos Basin is a typical cratonic petroliferous basin with 40 oil-gas bearing bed sets. It is featured as stable multicycle sedimentation, gentle formation, and less structures. The reservoir beds in Upper Paleozoic and Mesozoicare are mainly low density, low permeability, strong lateral change, and strong vertical heterogeneous. The well-known Loess Plateau in the southern area and Maowusu Desert, Kubuqi Desert and Ordos Grasslands in the northern area cover the basin, so seismic data acquisition in this area is very difficult and the data often takes on inadequate precision, strong interference, low signal-noise ratio, and low resolution. Because of the complicated condition of the surface and the underground, it is very difficult to distinguish the thin beds and study the land facies high-resolution lithologic sequence stratigraphy according to routine seismic profile. Therefore, a method, which have clearly physical significance, based on advanced mathematical physics theory and algorithmic and can improve the precision of the detection on the thin sand-peat interbed configurations of land facies, is in demand to put forward.Generalized S Transform (GST) processing method provides a new method of phase space analysis for seismic data. Compared with wavelet transform, both of them have very good localization characteristics; however, directly related to the Fourier spectra, GST has clearer physical significance, moreover, GST adopts a technology to best approach seismic wavelets and transforms the seismic data into time-scale domain, and breaks through the limit of the fixed wavelet in S transform, so GST has extensive adaptability. Based on tracing the development of the ideas and theories from wavelet transform, S transform to GST, we studied how to improve the precision of the detection on the thin stratum by GST.Noise has strong influence on sequence detecting in GST, especially in the low signal-noise ratio data. We studied the distribution rule of colored noise in GST domain, and proposed a technology to distinguish the signal and noise in GST domain. We discussed two types of noises: white noise and red noise, in which noise satisfy statistical autoregression model. For these two model, the noise-signal detection technology based on GST all get good result. It proved that the GST domain noise-signal detection technology could be used to real seismic data, and could effectively avoid noise influence on seismic sequence detecting.On the seismic profile after GST processing, high amplitude energy intensive zone, schollen, strip and lentoid dead zone and disarray zone maybe represent specifically geologic meanings according to given geologic background. Using seismic sequence detection profile and combining other seismic interpretation technologies, we can elaborate depict the shape of palaeo-geomorphology, effectively estimate sand stretch, distinguish sedimentary facies, determine target area, and directly guide oil-gas exploration.In the lateral reservoir prediction in XF oilfield of Ordos Basin, it played very important role in the estimation of sand stretch that the study of palaeo-geomorphology of Triassic System and the partition of inner sequence of the stratum group. According to the high-resolution seismic profile after GST processing, we pointed out that the C8 Member of Yanchang Formation in DZ area and C8 Member in BM area are the same deposit. It provided the foundation for getting 430 million tons predicting reserves and unite building 3 million tons off-take potential.In tackling key problem study for SLG gas-field, according to the high-resolution seismic sequence profile, we determined that the deposit direction of H8 member is approximately N-S or NNE-SS W. Using the seismic sequence profile, combining with layer-level profile, we can interpret the shape of entrenched stream. The sunken lenticle indicates the high-energy stream channel, which has stronger hydropower. By this way we drew out three high-energy stream channels' outline, and determined the target areas for exploitation. Finding high-energy braided river by high-resolution sequence processing is the key technology in SLG area.In ZZ area, we studied the distribution of the main reservoir bed-S23, which is shallow delta thin sand bed, by GST processing. From the seismic sequence profile, we discovered that the schollen thick sand beds are only local distributed, and most of them are distributary channel sand and distributary bar deposit. Then we determined that the S23 sand deposit direction is NW-SE in west, N-S in central and NE-SW in east. The high detecting seismic sequence interpretation profiles have been tested by 14 wells, 2 wells mismatch and the coincidence rate is 85.7%. Based on the profiles we suggested 3 predicted wells, one well (Yu54) completed and the other two is still drilling. The completed on Is coincident with the forecastThe paper testified that GST is a effective technology to get high- resolution seismic sequence profile, compartmentalize deposit microfacies, confirm strike direction of sandstone and make sure of the distribution range of oil-gas bearing sandstone, and is the gordian technique for the exploration of lithologic gas-oil pool in complicated areas.
Resumo:
This paper studies the radiation properties of the immiscible blend of nylon1010 and HIPS. The gel fraction increased with increasing radiation dose. The network was found mostly in nylon1010, the networks were also found in both nylon1010 and HIPS when the dose reaches 0.85 MGy or more. We used the Charleby-Pinner equation and the modified Zhang-Sun-Qian equation to simulate the relationship with the dose and the sol fraction. The latter equation fits well with these polymer blends and the relationship used by it showed better linearity than the one by the Charleby-Pinner equation. We also studied the conditions of formation of the network by the mathematical expectation theorem for the binary system. Thermal properties of polymer blend were observed by DSC curves. The crystallization temperature decreases with increasing dose because the cross-linking reaction inhibited the crystallization procession and destroyed the crystals. The melting temperature also reduced with increasing radiation dose. The dual melting peak gradually shifted to single peak and the high melting peak disappeared at high radiation dose. However, the radiation-induced crystallization was observed by the heat of fusion increasing at low radiation dose. On the other hand, the crystal will be damaged by radiation. A similar conclusion may be drawn by the DSC traces when the polymer blends were crystallized. When the radiation dose increases, the heat of fusion reduces dramatically and so does the heat of crystallization. (C) 1999 Elsevier Science Ltd. All rights reserved.
Resumo:
In the framework of the two-continuum approach, using the matched asymptotic expansion method, the equations of a laminar boundary layer in mist flows with evaporating droplets were derived and solved. The similarity criteria controlling the mist flows were determined. For the flow along a curvilinear surface, the forms of the boundary layer equations differ from the regimes of presence and absence of the droplet inertia deposition. The numerical results were presented for the vapor-droplet boundary layer in the neighborhood of a stagnation point of a hot blunt body. It is demonstrated that, due to evaporation, a droplet-free region develops near the wall inside the boundary layer. On the upper edge of this region, the droplet radius tends to zero and the droplet number density becomes much higher than that in the free stream. The combined effect of the droplet evaporation and accumulation results in a significant enhancement of the heat transfer on the surface even for small mass concentration of the droplets in the free stream. 在双连续介质理论框架下,采用匹配渐进展开方法导出并求解了具有蒸发液滴的汽雾流中层流边界层方程,给出了控制汽雾流的相似判据。对于沿曲面的流动,边界层方程的形式取决于是否存在液滴的惯性沉积。给出了热钝体验点附近蒸汽。液滴边界层的数值计算结果。它们表明:由于蒸发,在边界层内近壁处形成了一个无液滴区域;在该区上边界处,液滴半径趋于零而液滴数密度急剧增高。液滴蒸发及聚集的联合效应造成了表面热流的显著增加,甚至在自由来流中液滴质量浓度很低时此效应依然存在。
Resumo:
A mathematical model and approximate analysis for the energy distribution of an ac plasma arc with a moving boundary is developed. A simplified electrical conductivity function is assumed so that the dynamic behavior of the arc may be determined, independent of the gas type. The model leads to a reduced set of non-linear partial differential equations which governs the quasi-steady ac arc. This system is solved numerically and it is found that convection plays an important role, not only in the temperature distribution, but also in arc disruptions. Moreover, disruptions are found to be influenced by convection only for a limited frequency range. The results of the present studies are applicable to the frequency range of 10-10(2) Hz which includes most industry ac arc frequencies. (C) 1994 Academic Press, Inc.
Resumo:
This study deals with the formulation, mathematical property and physical meaning of the simplified Navier-Stokes (SNS) equations. The tensorial SNS equations proposed is the simplest in form and is applicable to flow fields with arbitrary body boundaries. The zones of influence and dependence of the SNS equations, which are of primary importance to numerical solutions, are expounded for the first time from the viewpoint of subcharacteristics. Besides, a detailed analysis of the diffusion process in flow fields shows that the diffusion effect has an influence zone globally windward and an upwind propagation greatly depressed by convection. The maximum upwind influential distance of the viscous effect and the relative importance of the viscous effect in the flow direction to that in the direction normal to the flow are represented by the Reynolds number, which illustrates the conversion of the complete Navier-Stokes (NS) equations to the SNS equations for flows with large Reynolds number.
Resumo:
The hierarchial structure and mathematical property of the simplified Navier-Stokesequations (SNSE) are studied for viscous flow over a sphere and a jet of compressible flu-id. All kinds of the hierarchial SNSE can be divided into three types according to theirmathematical property and also into five groups according to their physical content. Amultilayers structure model for viscous shear flow with a main stream direction is pre-sented. For the example of viscous incompressible flow over a flat plate there existthree layers for both the separated flow and the attached flow; the character of thetransition from the three layers of attached flow to those of separated flow is elucidated.A concept of transition layer being situated between the viscous layer and inviscidlayer is introduced. The transition layer features the interaction between viscous flow andinviscid flow. The inner-outer-layers-matched SNSE proposed by the present author inthe past is developed into the layers matched (LsM)-SNSE.
Resumo:
In this paper we explore techniques to identify sources of electric current systems and their channels of flow in solar active regions. Measured photospheric vector magnetic fields (VMF) together with high-resolution white-light and H filtergrams provide the data base to derive the current systems in the photosphere and chromosphere. Simple mathematical constructions of fields and currents are also adopted to understand these data. As an example, the techniques are then applied to infer current systems in AR 2372 in early April 1980. The main results are: (i) In unipolar sunspots the current density may reach values of 103 CGSE, and the Lorentz force on it can accelerate the Evershed flow, (ii) Spots exhibiting significant spiral pattrn in the penumbral filaments are the sources of vertical major currents at the photospheric surface, (iii) Magnetic neutral lines where the transverse field was strongly sheared were channels along which strong current system flows, (iv) The inferred current systems produced oppositely-flowing currents in the area of the delta configuration that was the site of flaring in AR 2372.
Resumo:
The microgravity research, as a branch of the advanced sciences and a spe- cialized field of high technology, has been made in China since the late 1980's. The research group investigating microgravity fluid physics consisted of our col- leagues and the authors in the Institute of Mechanics of the Chinese Academy of Sciences (CAS), and we pay special attention to the floating zone convection as our first research priority. Now, the research group has expanded and is a part of the National Microgravity Laboratory of the CAS, and the research fields have been extended to include more subjects related to microgravity science. Howev- er, the floating zone convection is still an important topic that greatly holds our research interests.
目录
1.1 floating-zone crystal growth
1.2 physical model
1.3 hydrodynamic model
1.4 mathematical model
references
2. basic features of floating zone convection
2.1 equations and boundary conditions
2.2 simple solutions of fz convection
2.3 solution for two-layers flow
2.4 numerical simulation
2.5 onset of oscillation
references
3. experimental method of fz convection
3.1 ground-based simulation experiments for pr≥1
3.2 temperature and velocity oscillations
3.3 optical diagnostics of free surface oscillation
3.4 critical parameters
3.5 microgravity experiments
3.6 ground-based simulation experiment for pr《1
4. mechanism on the onset of oscillatory convection
4.1 order of magnitude analysis
4.2 mechanism of hydrothermal instability
4.3 linear stability analysis
4.4 energy instability of thermocapillary convection
4.5 unsteady numerical simulation of 2d and 3d
4.6 two bifurcation transitions in the case of small pr number fluid
4.7 two bifurcation transitions in the case of large pr number fluid
4.8 transition to turbulence
references
5. liquid bridge volume as a critical geometrical parameter
5.1 critical geometrical parameters
5.2 ground-based and mierogravity experiments
5.3 instability analyses of a large prandtl number (pr≥1)fluid
5.4 instability analyses of a small prandtl number (pr《1)fluid
5.5 numerical simulation on two bifurcation process
references
6. theoretical model of crystal growth by the floating zone method
6.1 concentration distribution in a pure diffusion process
6.2 solutal capillary convection and diffusion
6.3 coupling with phase change convection
6.4 engineering model of floating zone technique
references
7. influence of applied magnetic field on the fz convection
7.1 striation due to the time-dependent convection
7.2 applied steady magnetic field and rotational magnetic field
7.3 magnetic field design for floating half zone
7.4 influence of magnetic field on segregation
references
8. influence of residual acceleration and g-jitter
8.1 residual acceleration in microgravity experiments
8.2 order of magnitude analyses (oma)
8.3 rayleigh instability due to residual acceleration
8.4 ground-based experiment affected by a vibration field
8.5 numerical simulation of a low frequency g-jitter
8.6 numerical simulation of a high frequency g-jitter
references
Resumo:
Abstract—Burst-and-coast is the most common locomotion type in freely routine swimming of koi carps (Cyprinus carpio koi), which consists of a burst phase and a coast phase in each cycle and mostly leads to a straight-line trajectory. Combining with the tracking experiment, the flow physics of koi carp’s burst-andcoast swimming is investigated using a novel integrated CFD method solving the body-fluid interaction problem. The dynamical equations of a deforming body are formulated. Following that, the loose-coupled equations of the body dynamics and the fluid dynamics are numerically solved with the integrated method. The two burst modes, MT (Multiple Tail-beat) and HT (Half Tail-beat), which have been reported by the experiments, are investigated by numerical simulations in this paper. The body kinematics is predicted and the flow physics is visualized, which are in good agreement with the corresponding experiments. Furthermore, the optimization on the energy cost and several critical control mechanisms in burst-and-coast swimming of koi carps are explored, by varying the parameters in its selfpropelled swimming. In this paper, energetics is measured by the two mechanical quantities, total output power CP and Froude efficiency Fr. Results and discussion show that from the standpoint of mechanical energy, burst-and-coast swimming does not actually save energy comparing with steady swimming at the same average speed, in that frequently changing of speed leads to decrease of efficiency.
Resumo:
According to the experimental results and the characteristics of the pressure-sensitive fractured formation, a transient flow model is developed for the deep naturally-fractured reservoirs with different outer boundary conditions. The finite element equations for the model are derived. After generating the unstructured grids in the solution regions, the finite element method is used to calculate the pressure type curves for the pressure-sensitive fractured reservoir with different outer boundaries, such as the infinite boundary, circle boundary and combined linear boundaries, and the characteristics of the type curves are comparatively analyzed. The effects on the pressure curves caused by pressure sensitivity module and the effective radius combined parameter are determined, and the method for calculating the pressure-sensitive reservoir parameters is introduced. By analyzing the real field case in the high temperature and pressure reservoir, the perfect results show that the transient flow model for the pressure-sensitive fractured reservoir in this paper is correct.
Resumo:
Intrinsically fuzzy morphological erosion and dilation are extended to a total of eight operations that have been formulated in terms of a single morphological operation--biased dilation. Based on the spatial coding of a fuzzy variable, a bidirectional projection concept is proposed. Thus, fuzzy logic operations, arithmetic operations, gray-scale dilation, and erosion for the extended intrinsically fuzzy morphological operations can be included in a unified algorithm with only biased dilation and fuzzy logic operations. To execute this image algebra approach we present a cellular two-layer processing architecture that consists of a biased dilation processor and a fuzzy logic processor. (C) 1996 Optical Society of America