基于暗通道先验条件的智能去云雾技术研究

常规基于暗通道先验条件的影像云雾去除算法,在处理影像时需手动多次设置增强系数,过程繁琐、效率较低,难以实现批量自动化去云雾处理。针对这一问题,本文提出了一种改进的去云雾方法,即利用二分法自动解算增强系数,基本实现对影像云雾的自适应、自动化去除。实验结果表明,该方法大幅提高了基于暗通道先验条件的影像云雾去除算法在工程化应用中的效率。

煤矿充水因素评价及涌水量预测

为真实掌握煤矿的涌水量和充水条件,在对煤矿水文地质分析的基础上,首先对充水条件和充水因素进行评价,得出煤矿的充水通道主要为导水裂隙带,基于层次分析得出通道条件的权重因子为0.2667最大,为该煤矿的充水的首要条件;在对煤矿历年涌水量观测结果分析的基础上,采用大井法对涌水量进行预测,综合分析最终得出该煤矿正常涌水量为462 m^(3)/h,最大涌水量为693 m^(3)/h。

黑龙江省东部地区对外贸易通道研究

本文对黑龙江省东部地区外港──俄罗斯远东南部港群的能力与现状，“中东”铁路的历史、能力现状与运能潜力等作了深入的研究，并运用路线比较模型与重力模型对哈尔滨──绥芬河──海参崴铁路通道条件的吸引力进行了分析。笔者认为，中俄公路运输的发展是其对外通道的新优势。

大斗沟煤矿充水因素分析及涌水量预测

在介绍大斗沟煤矿水文地质条件的基础上,重点对矿井充水条件和充水因素进行分析,得出大斗沟煤矿的充水通道主要为导水裂缝带。基于层次分析,得出充水通道条件的权重因子为0.2667,为该煤矿充水的最大权重,即首要条件;在对煤矿历年涌水量观测结果分析的基础上,分别采用大井法和水文地质比拟法对矿井涌水量进行预测,综合分析该煤矿正常涌水量为462 m^(3)/h,最大涌水量为693 m^(3)/h。

深汕高速铁路坪山东隧道规划建设方案

新建深汕高速铁路(深圳—汕尾)坪山东隧道沿线城市建筑密集,施工环境复杂,规划选线不当极易对城市规划建设产生巨大影响。本文结合地质环境提出两种线路方案,从通道条件、运行时间、工程经济三方面进行对比分析,确立最佳线路方案。在此基础上选取了三种典型工况,建立了盾构隧道近接高速铁路桥梁施工数值模型,研究既有高速铁路桥梁对城市高速铁路规划的影响。结果表明:沿厦深铁路方案的并行段落长且运行时间短,较为可行;埋深最大断面处邻近桥梁桩身最大位移为0.43 mm,距桥桩最近断面处地层最大位移为1.22 mm,邻近桩身最大位移为0.36 mm;在困难地段施作隔离桩可以有效控制桩基础变形。

南京地区客票中心投入运行

1998年3月31日,上海铁路局票务中心南京地区中心在部客票总体组、上海局、南京分局客运、电务、电算等部门的全 j面配合下,正式开通运行。从3月27日开始至3月31日晚,中华门、南京西、南京站、南京北、镇江、丹阳。

Applications of Pre-Geological Prediction in Tunnel Construction

Pre-geological prediction (PGP) is defined as the prediction of engineering geologic condition and hy-drogeological condition certain distance ahead of the working face. The purpose of this paper is to introduce mainlygeologic survey before and in excavation, to clarify their emphasis on PGP. At the same time, the technique is appliedto an engineering case, the longest highway tunnel in Gansu province. Data of geological survey of outside tunnels,sound wave detection, and geologic sketch for both tunnel face and sidewalls within the tunnel are analyzed. Afteranalyzing these data, long-term pre-geological prediction forecasting basic geological conditions of fault 4 such aslithology, scope, location, etc., and short-term and more accurate pre-geological prediction are reported.

Predicting Siltation in Entrance Channel Based on Wind Conditions

The siltation induced by wind waves in an entrance channel is one of the prime factors influencing the operation efficiency of a port. It is necessary to predict the siltation accurately for dredging and ship operation passing through the entrance of the port. However, it is difficult to apply the traditional method to predicting entrance siltation because of its complex computational procedure and lacking the data of ocean dynamic elements in the specified sea area. From the view of energy conservation, a direct relationship between wind conditions and sediment deposition can be founded. On the basis of the above methodology, an empirical formula expressed by wind conditions for forecasting the siltation in the entrance channel is set up. The wind conditions are easily obtained from the local meteorological stations or weather maps, so the formula established in this paper is more convenient and practical than the traditional method. A case study is provided, in which the emopirical formula is calibrated and verified utilizing the measured wind and siltation conditions in the entrance channel of the port. Comparisons between computed values and measured data show satisfactory aqreement.

Mixed convective heat and mass transfer analysis for peristaltic transport in an asymmetric channel with Soret and Dufour effects

The present investigation addresses the simultaneous effects of heat and mass transfer in the mixed convection peristaltic flow of viscous fluid in an asymmetric channel. The channel walls exhibit the convective boundary conditions. In addition, the effects due to Soret and Dufour are taken into consideration. Resulting problems are solved for the series solutions. Numerical values of heat and mass transfer rates are displayed and studied. Results indicate that the concentration and temperature of the fluid increase whereas the mass transfer rate at the wall decreases with increase of the mass transfer Biot number. Furthermore, it is observed that the temperature decreases with the increase of the heat transfer Biot number.

Developing Flow Pressure Drop and Friction Factor of Water in Copper Microchannels

Experiments of de-ionized water flowing in microchannels made in copper blocks were carried out to obtain pressure drop and friction factor and to investigate any possible discrepancies from conventional theory. Three channels with widths of 0.5 mm, 1.0 mm, 1.71 mm, a depth of 0.39 mm and a length of 62 mm were tested. For adiabatic tests, the temperature of the working fluid was maintained at 30 ℃, 60 ℃ and 90 ℃ without any heat fluxes supplied to the test section. The experimental conditions covered a range of Reynolds numbers from 234 to 3,430. For non-adiabatic tests, the inlet temperature and heat flux applied were 30 ℃ and 147 kW/m2 and only for the 0.635 mm channel. The friction factors obtained for the widest channel （Dh = 0.635 mm） are reported for both adiabatic and non-adiabatic experiments to assess possible temperature effects. The paper focuses on the effect of hydraulic diameter on pressure drop and friction factor over the experimental conditions. The pressure drop was found to decrease as the inlet temperature was increased, while the friction factors for the three test sections did not show significant differences. The experimental friction factors were in reasonable agreement with conventional developing flow theory. The effect of temperature on friction factor was not considerable as the friction factor with and without heat flux was almost the same.

Effects of river width changes on flow characteristics based on flume experiment

The rapid changes in flow pattern due to varying channel widths will make significantly impact on the hydraulic structures and evolutions of open channel. To better understand the impact of varying width, a flume experiment with adjustable width and a depth-averaged two-dimension numerical model were used to analyze the variations of flow parameters. Our experimental results showed that flow velocity gradually increased with decreasing water depth in converging region, and decreased with increasing water depth in diverging zones. It was also found that the turbulence intensity laws in three directions were not agreed with the theoretical relationships proposed by Nezu and Nakagawa in 1993 in straight open channel flows. The flow in the channel with varying width may change from the supercritical flow to the subcritical flow as a function of Froude number. Our numerical simulations with different flow rates showed that most of the hydraulic jumps in diverging region were submerged jump and the degree of submergence increased with increasing flow rate in gradual channel transition. When the flow rate increased, the range of supercritical flow rapidly decreased and the flow changed from the supercritieal condition to the subcritical condition in diverging sections.

Analysis of 2D Flow and Heat Transfer Modeling in Fracture of Porous Media

Heat and mass transfer between porous media and fluid is a complex coupling process, which is widely used in various fields of engineering applications, especially for natural and artificial fractures in oil and gas extraction. In this study, a new method is proposed to deal with the flow and heat transfer problem of steady flow in a fracture. The fluid flow in a fracture was described using the same method as Mohais, who considered a fracture as a channel with porous wall, and the perturbation method was used to solve the mathematical model. Unlike previous studies, the shear jump boundary condition proposed by Ochoa-Tapia and Whitaker was used at the interface between the fluid and porous media. The main methods were perturbation analysis and the application of shear jump boundary conditions. The influence of permeability, channel width, shear jump degree and effective dynamic viscosity on the flow and heat transfer in the channel was studied by analysing the analytical solution. The distribution of axial velocity in the channel with the change of the typical parameters and the sensitivity of the heat transfer was obtained.

A Novel Deterministic Secure Quantum Communication Scheme with Einstein–Podolsky–Rosen Pairs and Single Photons

A novel deterministic secure quantum communication （DSQC） scheme is presented based on Einstein- Podolsky-Rosen （EPR） pairs and single photons in this study. In this scheme, the secret message can be encoded directly on the first particles of the prepared Bell states by simple unitary operations and decoded by performing the Bell-basis measurement after the additional classic information is exchanged. In addition, the strategy with two-step transmission of quantum data blocks and the technique of decoy-particle checking both are exploited to guarantee the security of the communication. Compared with some previous DSQC schemes, this scheme not oniy has a higher resource capacity, intrinsic efficiency and total efficiency, but also is more realizable in practical applications. Security anaJysis shows that the proposed scheme is unconditionally secure against various attacks over an ideal quantum channel and still conditionally robust over a noisy and lossy quantum channel.

Flow rate limitation in open wedge channel under microgravity

A study of flow rate limitation in an open wedge channel is reported in this paper. Under microgravity condition, the flow is controlled by the convection and the viscosity in the channel as well as the curvature of the liquid free surface. A maximum flow rate is achieved when the curvature cannot balance the pressure difference leading to a collapse of the free surface. A 1-dimensional theoretical model is used to predict the critical flow rate and calculate the shape of the free surface. Computa- tional Fluid Dynamics tool is also used to simulate the phenomenon. Results show that the 1-dimensional model overestimates the critical flow rate because extra pressure loss is not included in the governing equation. Good agreement is found in 3-dim- ensional simulation results. Parametric study with different wedge angles and channel lengths show that the critical flow rate increases with increasing the cross section area; and decreases with increasing the channel length. The work in this paper can help understand the surface collapsing without gravity and for the design in propellant management devices in satellite tanks.

Emergence of target waves in neuronal networks due to diverse forcing currents

The electric activities of neurons could be changed when ion channel block occurs in the neurons.External forcing currents with diversity are imposed on the regular network of Hodgkin-Huxley(HH) neuron,and target waves are induced to occupy the network.The forcing current I1 is imposed on neurons in a local region with m 0 ×m 0 nodes in the network,neurons in other nodes are imposed with another forcing current I2.Target wave could be developed to occupy the network when the gradient forcing current(I1-I2) exceeds certain threshold,and the formation of target wave is independent of the selection of boundary condition.It is also found that the developed target wave can decrease the negative effect of ion channel block and suppress the spiral wave,and thus channel noise is also considered.The potential mechanism of formation of target wave could be that the gradient forcing current(I1-I2) generates quasi-periodical signal in local area,and the propagation of quasi-periodical signal induces target-like wave due to mutual coupling among neurons in the network.

A twin-channel difference model for cross-calibration of thermal infrared band

Based on the conduction and transformation of the thermal infrared radiative transfer equation of water target,a twinchannel difference model(DM) was proposed to improve the calibration precision by conquering the limitation that the atmospheric condition when image is acquiring cannot be truly obtained in the traditional radiometric simulation calibration method.The analysis of surface,atmosphere and top-of-atmosphere(TOA) radiative energy decomposition demonstrated that the apparent TOA radiance of the uncalibrated channel is the differential combination of two reference channels.The DM avoids impacts from atmospheric temperature and density.The only impact is from water vapor(WV) content.Based on the fitting error analysis of 742 mid-latitude atmospheric profiles(column WV content:0-5×10 3 atm cm) selected from TIGR database,the DM is insensitive to WV content.The maximum error is less than 0.2 K when the view zenith angels(VZAs) of reference channels and uncalibrated channel are less than 30.The error becomes 0.3 K when VZAs range from 30 to 40 and 0.6 K when VZAs are in 40-50.Because the uncertainty increases when VZAs are larger than 50,the best range of VZAs is 30-50.The vicarious calibration results at Lake Qinghai field indicated that the calibration precision of the DM cross-calibration by using MODIS bands 31 and 32 as reference channels to calibrate IRS band 08 is similar to that of vicarious calibration.Therefore,the DM is a reliable alternative tool for sensor on-orbit calibration and validation with high precision and frequency.

A new kind of optimal second-order symplectic scheme for seismic wave simulations

Here we introduce generalized momentum and coordinate to transform seismic wave displacement equations into Hamiltonian system.We define the Lie operators associated with kinetic and potential energy,and construct a new kind of second order symplectic scheme,which is extremely suitable for high efficient and long-term seismic wave simulations.Three sets of optimal coefficients are obtained based on the principle of minimum truncation error.We investigate the stability conditions for elastic wave simulation in homogeneous media.These newly developed symplectic schemes are compared with common symplectic schemes to verify the high precision and efficiency in theory and numerical experiments.One of the schemes presented here is compared with the classical Newmark algorithm and third order symplectic scheme to test the long-term computational ability.The scheme gets the same synthetic surface seismic records and single channel record as third order symplectic scheme in the seismic modeling in the heterogeneous model.

Non-ideal space division multiple access and its application

We study the performance of space division multiple access （SDMA） under a non-ideal engineering situation. When the SDMA channel is of high inter-layer correlation and the condition number is large, the multiple user multiple input and multiple output user equipment （MUMIMOUE） grouping should be optimized, and in some cases further dimension-reduction should be applied. As the channel measuring is always non-ideal, we use two methods, feedback mode and non-feedback mode, in terms of performance and overhead. It is proposed that the non-feedback mode is preferable even for some non-reciprocal channels. Prin- ciple analysis and test results are given.

Transport of Cu-H2O nanofluid through a channel with wavy walls under velocity slip and connective boundary conditions

Present study examines the mixed convective peristaltic transport of Cu-H2O nanofluid with velocity slip and convective boundary conditions. Analysis is performed using the two-phase model of the nanofluid. Viscous dissipation and heat generation/absorption effects are also taken into account. Problem is formulated using the long wavelength and low Reynolds number approach. Numerical solutions for the pressure rise per wavelength, pressure gradient, axial velocity, temperature and heat transfer rate at the boundaxy are obtained and studied through graphs. Results show that the area of peristaltic pumping decreases with an increase in the nanoparticles volume fraction. Increase in the velocity slip parameter shows an increase of the pressure gradient in the occluded part of the channel. Further, addition of copper nanoparticles reduces both the axial velocity and temperature of the base fluid. Temperature of the nanofluid also decreases sufficiently for an increase in the value of Blot number.

The Stability of Multi-modal Traffic Network

There is an explicit and implicit assumption in multimodal traffic equilibrium models, that is, if the equilibrium exists, then it will also occur. The assumption is very idealized; in fact, it may be shown that the quite contrary could happen, because in multimodal traffic network, especially in mixed traffic conditions the interaction among traffic modes is asymmetric and the asymmetric interaction may result in the instability of traffic system. In this paper, to study the stability of multimodal traffic system, we respectively present the travel cost function in mixed traffic conditions and in traffic network with dedicated bus lanes. Based on a day-to-day dynamical model, we study the evolution of daily route choice of travelers in multimodal traffic network using 10000 random initial values for different cases. From the results of simulation, it can be concluded that the asymmetric interaction between the cars and buses in mixed traffic conditions can lead the traffic system to instability when traffic demand is larger. We also study the effect of travelers' perception error on the stability of multimodal traffic network. Although the larger perception error can alleviate the effect of interaction between cars and buses and improve the stability of traffic system in mixed traffic conditions, the traffic system also become instable when the traffic demand is larger than a number. For all cases simulated in this study, with the same parameters, traffic system with dedicated bus lane has better stability for traffic demand than that in mixed traffic conditions. We also find that the network with dedicated bus lane has higher portion of travelers by bus than it of mixed traffic network. So it can be concluded that building dedicated bus lane can improve the stability of traffic system and attract more travelers to choose bus reducing the traffic congestion.