多层介质地层中有低速层出现时的陷模研究

在三维情况下，利用Ｂ，Ｐ，Ｃ坐标系研究了水平多层介质中导波的能量分布，提出了一种计算大深度处位移和能流密度的方法，避免了精度丢失问题。在有低速层介质情况下，在深入分析瑞利模的基础上，首次研究了陷模的频散及能流分布，分析了它们的传播机制。导波能量可能分布在自由表面附近，表现为面波；也可能集中在自由界面下某一深度处，表现为沿低速层延伸方向传播的导波。

Forming defects in aluminum alloy hot stamping of side-door impact beam

The forming defects, including thinning, rupture, wrinkling and springback, usually arising in producing a side-door impact beam, were investigated by trial and numerical simulation. A temperature-related constitutive model specific to the temperature range from 350 °C to 500 °C was established and used for the numerical simulation. The trial and numerical simulation were conducted to clarify the quantitative characteristics of forming defects and to analyze the effects of process parameters on the forming defects. Results show that the rupture situation is ameliorated and the springback is eliminated in the aluminum alloy hot stamping. The wrinkling severity decreases with increasing blank holder force (BHF), but the BHF greater than 15 kN causes the rupture at the deepest drawing position of workpiece. The forming defects are avoided with lubricant in the feasible ranges of process parameters: the BHF of 3 to 5 kN and the stamping speed of 50 to 200 mm/s.

Yield Modeling of Rectangular Defect Outline

In integrated circuits, the defects associated with photolithography are assumed to be in the shape of circular discs in order to perform the estimation of yield and fault analysis. However,real defects exhibit a great variety of shapes. In this paper,a novel yield model is presented and the critical area model of short circuit is correspondingly provided. In comparison with the circular model corrently available, the new model takes the similarity shape to an original defect, the two-dimensional distributional characteristic of defects, the feature of a layout routing and the character of yield estimation into account. As for the aspect of prediction of yield, the experimental results show that the new model may predict the yield caused by real defects more accurately than the circular model does. It is significant that the yield is accurately estimated and improved using the proposed model.

Experimental research on ultimate bearing capacity of N-joints of grouted square steel tube trusses

Cave-in failure is apt to occur in joints of trusses made of square hollow sections. In order to turn the failure mode into a strength failure mode of joint members, the idea is proposed that the chord of the truss is grouted to increase the cave-in beating capacity of a hollow tube chord. An experiment of eight specimens of N- joints made of grout-filled square steel tubes is performed. Based on the experimental study, the geometrical parameters of specimens are analyzed, and the effects of the confinement index ε, the spacing between the two web members g and the ratio of side length of the vertical web member to that of the chord β on the behavior of specimens are investigated through simulation analysis by simulation analyses, the mechanical properties and the failure an ANSYS program. Based on the test results and modes of this kind of joints are analyzed and the formulae to predict the ultimate bearing capacities corresponding to different failure modes are developed. The ultimate bearing capacity of compressive N-joints is calculated in accordance with the cave-in failure mode of a chord member; the ultimate bearing capacity of tension N-joints is calculated in accordance with the punchingshear failure mode; the ultimate bearing capacity of a chord member is calculated in accordance with the shear failure mode in normal sections.

A Novel Algorithm to Extract Weighted Critical Area

inductive fault analysis is a technique for enumerating likely bridges that is limited by the weighted critical area computation. Based on the rectangle model of a real defect and mathematical morphology, an efficient algorithm is presented to compute the weighted critical area of a layout. The algorithm avoids the need to determine which rectangles belong to a net and the merging of the critical area corresponding to a net pair. Experimental resuits showing the algorithm＇s performance are presented.

Temperature-Dependent Raman Scattering of Phonon Modes and Defect Modes in GaN and p-Type GaN Films

Raman spectra of undoped GaN and Mg-doped GaN films grown by metal-organic chemical-vapor deposition on sapphire are investigated between 78 and 573K.A peak at 247cm -1 is observed in both Raman spectra of GaN and Mg-doped GaN.It is suggested that the defect-induced scattering is origin of the mode.The electronic Raman scattering mechanism and Mg-related local vibrational mode are excluded.Furthermore,the differences of E_2 and A_1(LO) modes in two samples are also discussed.The stress relaxation is observed in Mg-doped GaN.

Defect in photonic crystal with negative index material

The transmission property of the photonic crystal containing negative index material is analyzed by means of transfer matrix method.It is demonstrated that a defect mode appears in the conventional Bragg gap and the defect mode is sensitive to the position of the defect cell.For the first time to our knowledge we introduce two defects into such a structure and discuss the dependence of the transmission on the interval of the two defect cells.It is found that a wide degenerate defect mode appears in the Bragg gap,and this degenerate defect mode splits into two different defect modes when the two defect cells become closer.

Prismatic and full-waveform joint inversion

Prismatic wave is that it has three of which is located at the reflection interface reflection paths and two reflection points, one and the other is located at the steep dip angle reflection layer, so that contains a lot of the high and steep reflection interface information that primary cannot reach. Prismatic wave field information can be separated by applying Born approximation to traditional reverse time migration profile, and then the prismatic wave is used to update velocity to improve the inversion efficiency for the salt dame flanks and some other high and steep structure. Under the guidance of this idea, a prismatic waveform inversion method is proposed （abbreviated as PWI）. PWI has a significant drawback that an iteration time of PWI is more than twice as that of FWI, meanwhile, the full wave field information cannot all be used, for this problem, we propose a joint inversion method to combine prismatic waveform inversion with full waveform inversion. In this method, FWI and PWI are applied alternately to invert the velocity. Model tests suggest that the joint inversion method is less dependence on the high and steep structure information in the initial model and improve high inversion efficiency and accuracy for the model with steep dip angle structure.

Fracture strength of centre surface cracked tensile specimens made of 2219-T87 Al alloy welding

Fracture data of both parent metal and weldment metals from surface cracked tensile plates made of 2219-T87 Al alloy at cryogenic temperatures were correlated using a modified inherent flaw model. Fracture parameters to generate the failure assessment diagram were determined for the material. Fracture analysis was carried out considering the ultimate tensile strength value and the fracture data of aluminium base metal and weldment metal generated from center–surface cracked tensile specimens having different thicknesses. The failure assessment diagram of a material generated from tensile fracture plate configuration can be applied to failure pressure estimation of any cracked component, made of the same material.

Modeling and Analyzing Web Application with Aspect-Oriented Hierarchical Coloured Petri Nets

Aspect-oriented modeling can uncover potential design faults, yet most existing work fails to achieve both separation and composition in a natural and succinct way. This study presents an aspect-oriented modeling and analysis approach with hierarchical Coloured Petri Nets(HCPN). HCPN has sub-models and well-defined semantics combining a set of submodels. These two characteristics of HCPN are nicely integrated into aspect oriented modeling. Submodels are used to model aspects while the combination mechanism contributes to aspects weaving. Furthermore, the woven aspect oriented HCPN model can be simulated and analyzed by the CPN Tools. A systematic web application case study is conducted. The results show the system original properties are satisfied after weaving aspects and all design flaws are revealed. As such, the approach can support web application design and analysis in an aspect-oriented fashion concisely and effectively.

THE APPLICATION OF ACOUSTIC LOGGING METHOD IN THE MODEL AND PARAMETERS IDENTIFICATION OF ROCK MASS

This paper describes the new method that is introduced into prediction of subsidence using system engineering method with acoustic logging and density logging. According to the result of acoustic logging, the real and complex rock beds are divided into a set of different bed groups and the equivalent mechanical model is to be built. Based on the modern control theory,according to the input data (convergence or settlement of the roof) and the output data (surface movement and deformation) of the system, the static parameters of equivalent rock beds can be derived from back calculation using the optimum method. Then the reqression relationship between the dynamic and static parameters can be built. So the prediction of rock and ground movements for other areas in the same district can be done, when using this relationship with the acoustic logging data and density logging data in situ.

Position Dependent Spontaneous Emission Spectra of a Λ-Type Atomic System Embedded in a Defective Photonic Crystal

We investigate the position dependent spontaneous emission spectra of a A-type three-level atom with one transition coupled to the free vacuum reservoir and the other one coupled to a double-band photonic band gap reservoir with a defect mode in the band gap. It is shown that, for the atom at the defect location, we have a two-peak spectrum with a wide dark line due to the strong coupling between the atom and the defect mode. While, when the atom is far from the defect location （or in the absence of the defect mode）, the spectrum has three peaks with two dark lines due to the coupling between the atom and the photonic band gap reservoir with the largest density of states near the band edges. On the other hand, we have a four-peak spectrum for the atom at the space in between. Moreover, the average spontaneous emission spectra of the atoms uniformly embedded in high dielectric or low dielectric regions are described. It is shown that the atoms embedded in high （low） dielectric regions far from the defect location, effectively couple to the modes of the lower （upper） photonic band. However, the atoms embedded in high dielectric or low dielectric regions at the defect location, are coupled mainly to the defect modes. While, the atoms uniformly embedded in high （low） dielectric regions with a normal distance from the defect location, are coupled to both of defect and lower （upper） photonic band modes.

Detection of Fabric Defects with Fuzzy Label Co-occurrence Matrix Set

Co-occurrence matrices have been successfully applied in texture classification and segmentation.However,they have poor computation performance in real-time application.In this paper,the efficient co-occurrence matrix solution for defect detection is focused on,and a method of Fuzzy Label Co-occurrence Matrix (FLCM) set is proposed.In this method,all gray levels are supposed to subject to some fuzzy sets called fuzzy tonal sets and three defective features are defined.Features of FLCM set with various parameters are combined for the final judgment.Unlike many methods,image acquired for learning hasn't to be entirely free of defects.It is shown that the method produces high accuracy and can be a competent candidate for plain colour fabric defect detection.

Time series prediction of mining subsidence based on a SVM

In order to study dynamic laws of surface movements over coal mines due to mining activities,a dynamic prediction model of surface movements was established,based on the theory of support vector machines(SVM) and times-series analysis.An engineering application was used to verify the correctness of the model.Measurements from observation stations were analyzed and processed to obtain equal-time interval surface movement data and subjected to tests of stationary,zero means and normality.Then the data were used to train the SVM model.A time series model was established to predict mining subsidence by rational choices of embedding dimensions and SVM parameters.MAPE and WIA were used as indicators to evaluate the accuracy of the model and for generalization performance.In the end,the model was used to predict future surface movements.Data from observation stations in Huaibei coal mining area were used as an example.The results show that the maximum absolute error of subsidence is 9 mm,the maximum relative error 1.5%,the maximum absolute error of displacement 7 mm and the maximum relative error 1.8%.The accuracy and reliability of the model meet the requirements of on-site engineering.The results of the study provide a new approach to investigate the dynamics of surface movements.

3-D discontinuum numerical modeling of subsidence incorporating ore extraction and backfilling operations in an underground iron mine in China

An underground iron mine in China has been used as a case-study to research the subsidence due to ore extraction and backfilling during open stoping operations. A 3-D discontinuum numerical model was built incorporating geologic complexities including faults and interfaces between different lithologies,and the stoping and backfilling sequence adopted from the mine plans. The stoping was carried out in two vertically stacked horizontal layers, with a total of 16 stopes. Large displacements of up to 50 cm were observed along the roof of the stopes, and a maximum surface subsidence of 22.5 cm was observed.Backfilling was found to eliminate subsequent displacements and subsidence. The extraction of the upper orebody was found to influence displacements in the lower orebody. Finally, a subsidence profile was constructed to show the subsidence at all locations along the length of the surface and region of influence on the surface.

Generation of Superpositions of Two-Mode Coherent States for the Motion of Two Trapped Ions

We propose a method for the generation of superpositions of two-mode coherent states for the center-of-mass and relative vibrational modes of two trapped ions. In the scheme the ions are driven by a single travelling-wave laser field tuned to the carrier. Then a measurement of the internal states collapses the vibrational modes to the entangled coherent state.

Development of Automatic Extraction Weld for Industrial Radiographic Negative Inspection

In industrial X-ray inspection, in order to identify weld defects automatically, raise the identification ratio, and avoid processing of complex background, it is an important step for sequent processing to extract weld from the image. According to the characteristics of weld radiograph image, median filter is adopted to reduce the noise with high frequency, then relative gray-scale of image is chosen as fuzzy characteristic, and image gray-scale fuzzy matrix is constructed and suitable membership function is selected to describe edge characteristic. A fuzzy algorithm is adopted for enhancing radiograph image processing. Based on the intensity distribution characteristic in weld, methodology of weld extraction is then designed. This paper describes the methodology of all the weld extraction, including reducing noise, fuzzy enhancement and weld extraction process. To prove its effectiveness, this methodology was tested with 64 weld negative images available for this study. The experimental results show that this methodology is very effective for extracting linear weld.

Effects of Probability of Revelation of Defection and Penalty to Defection on Cooperative Behavior in 2-Person Prisoner＇s Dilemma Game

In our society, it is a major issue to enhance cooperative behaviors. Without this, our society fall into social dilemma situations, and gets worse and worse. Such a situation in an organization leads to violation of social or organizational rules, and at the worst case it suffers from serious accidents or scandals. Therefore, it is important for organizational managers to make efforts and take measures to enhance cooperative behaviors. Although there seem to be many ways to constantly elicit cooperative behaviors, the punishment is one of the most effective measures for enhancing cooperation. This study focused on the effects of penalty and probability of the revelation of defection on the cooperation, and getting insight into how punishment strategy should be used to get rid of social dilemmas and enhance cooperation. This study conducted a simulation experiment to find the proper penal regulations condition that can suppress violations （defective behavior） in a 2-person prisoner＇s dilemma situation. The effects of probability of the revelation of defection and penalty to revelation on the cooperative behavior were identified with the interactive effect of both experimental factors. The defection （uncooperative behavior） decreased when the penalty to the defection was heavy and the probability of the revelation of defection was low than that when the penalty to the defection was light and the probability of the revelation of the defection was high.

Selectivity of escape-hole size in tube traps for white-spotted conger Conger myriaster

Comparative fishing experiments were carried out in 2010 using tube traps with five hole diameters (8, 15, 18, 20 and 22 mm) to establish the size selectivity of escape holes for white-spotted conger. Selectivity and split parameters of the SELECT model were calculated using the estimated-split and equal-spilt model. From likelihood ratio tests and AIC (Akaike's Information Criterion) values, the estimated-split model was selected as the best-fit model. Size selectivity of escape holes in the tube traps was expressed as a logistic curve, similar to mesh selectivity. The 50% selection length of white-spotted conger in the estimated-split model was 28.26, 33.35, 39.31 and 47.30 cm for escape-hole diameters of 15, 18, 20 and 22 mm, respectively. The optimum escape-hole size is discussed with respect to management of the white-spotted conger fishery. The results indicate that tube traps with escape holes of 18 mm in diameter would benefit this fishery.

A Stochastic Model for Optimizing the Patching Time of Software Bugs

New bugs and vulnerabilities are discovered and reported from time to time even after software products are released. One of the common ways to handle these bugs is to patch the software. In this paper, the authors propose a stochastic model for optimizing the patching time for software bugs and vulnerabilities. The optimal patching time can be computed in the patching script development and operational costs in fix. The authors present two case studies using the Nimda worm vulnerability in Microsoft Internet Information Services web server and the bug report of the Debian project. These studies indicate that the patch applications are later than their optimal fix time.