顶盖多工位级进模设计与制造

顶盖多工位级进模设计与制造安徽省滁州无线电厂陈卫国１引言图１所示制件，原采用３副模具冲压成形，除了第１道（冲孔、打筋、落料）工序外，其余２道工序（首弯和成形）的定位都是采用７×１．６ｍｍ的方孔。我们对ＴＪＴ－２Ｃ顶盖零件模具进行了技术改进，根据我厂现...

Slope displacement prediction based on multisource domain transfer learning for insufficient sample data

Accurate displacement prediction is critical for the early warning of landslides.The complexity of the coupling relationship between multiple influencing factors and displacement makes the accurate prediction of displacement difficult.Moreover,in engineering practice,insufficient monitoring data limit the performance of prediction models.To alleviate this problem,a displacement prediction method based on multisource domain transfer learning,which helps accurately predict data in the target domain through the knowledge of one or more source domains,is proposed.First,an optimized variational mode decomposition model based on the minimum sample entropy is used to decompose the cumulative displacement into the trend,periodic,and stochastic components.The trend component is predicted by an autoregressive model,and the periodic component is predicted by the long short-term memory.For the stochastic component,because it is affected by uncertainties,it is predicted by a combination of a Wasserstein generative adversarial network and multisource domain transfer learning for improved prediction accuracy.Considering a real mine slope as a case study,the proposed prediction method was validated.Therefore,this study provides new insights that can be applied to scenarios lacking sample data.

ANALYSIS AND CALCULATION ON FRICTION AND WEAR RELIABILITY OF SOME PLANE′S FLAP MECHANISM

The mathematical model of the motion of some plane′s flap mechanism is set up by the method of establishing mathematical model of space mechanism. When the input parameter is given, the theoretical output parameter of the flap mechanism is achieved by the model. The wear and tear volume is introduced into the mathematical model, and if the input parameter is the same, the real output parameter of the flap mechanism worn can be obtained. On the basis of this, it is able to achieve the friction and the wear reliability of the flap mechanism.

Identification and Quantification of Non-Spherical Particles

In commercial applications of phase Doppler anemometry (PDA), the effectiveness of non sphericity of particles is present and the response of PDA system deviates from the theoretical prediction. In this paper, the statistic characteristics of PDA signal related to irregular particles is analyzed and a method of statistic classification of irregular particles is proposed.It proves that the parameter of PDA signal for irregular particles is an unbiased estimation for spherical ones, the mean of the phase difference is in direct proportion to the mean diameter of particles and the standard deviation of the phase difference increases linearly with the standard deviation of irregular particles. As an application of the identification of irregular objects, fuzzy patterns and similarities of haemocytes are used to recognize and quantify cell samples.The statistic classification of particles is more significant in practice.

Modeling of the Multi-Target Locating and Tracking in the Field Artillery System

A method for the multi target locating and tracking with the multi sensor in a field artillery system is studied. A general modeling structure of the system is established. Based on concepts of cluster and closed ball, an algorithm is put forward for multi sensor multi target data fusion and an optimal solution for state estimation is presented. The simulation results prove the algorithm works well for the multi stationary target locating and the multi moving target tracking under the condition of the sparse target environment. Therefore, this method can be directly applied to the field artillery C 3I system.

ulti-azimuth three-component surface seismic modeling for viscoelastic cracked monoclinic media

In this article, a method of high order, staggered grid, finite difference was used to model snapshots of seismic wave propagation and multi-azimuth surface seismic records in viscoelastic cracked monoclinic media. The modeling results clearly show the anisotropy caused by the crack fill material and the viscoelastic wave field through the monoclinic media. Summarizing the regularity of seismic records for different azimuths, this study is a significant attempt to understand the wave fields propagated in real media and to propose a more rational theoretical model for the future.

Damage alarming for bridge expansion joints using novelty detection technique based on long-term monitoring data

Damage alarming and safety evaluation using long-term monitoring data is an area of significant research activity for long-span bridges. In order to extend the research in this field, the damage alarming technique for bridge expansion joints based on long-term monitoring data was developed. The effects of environmental factors on the expansion joint displacement were analyzed. Multiple linear regression models were obtained to describe the correlation between displacements and the dominant environmental factors. The damage alarming index was defined based on the multiple regression models. At last, the X-bar control chart was utilized to detect the abnormal change of the displacements. Analysis results reveal that temperature and traffic condition are the dominant environmental factors to influence the displacement. When the confidence level of X-bar control chart is set to be 0.003, the false-positive indications of damage can be avoided. The damage sensitivity analysis shows that the proper X-bar control chart can detect 0.1 cm damage-induced change of the expansion joint displacement. It is reasonably believed that the proposed technique is robust against false-positive indication of damage and suitable to alarm the possible future damage of the expansion joints.

Numerical Simulation of Multi-Directional Random Wave Transformation in a Yacht Port

This paper extends a prediction model for multi-directional random wave transformation based on an energy balance equation by Mase with the consideration of wave shoaling, refraction, diffraction, reflection and breaking. This numerical model is improved by 1) introducing Wen's frequency spectrum and Mitsuyasu's directional function, which are more suitable to the coastal area of China; 2) considering energy dissipation caused by bottom friction, which ensures more accurate results for large-scale and shallow water areas; 3) taking into account a non-linear dispersion relation. Predictions using the extended wave model are carried out to study the feasibility of constructing the Ai Hua yacht port in Qingdao, China, with a comparison between two port layouts in design. Wave fields inside the port for different incident wave directions, water levels and return periods are simulated, and then two kinds of parameters are calculated to evaluate the wave conditions for the two layouts. Analyses show that Layout I is better than Layout II. Calculation results also show that the harbor will be calm for different wave directions under the design water level. On the contrary, the wave conditions do not wholly meet the requirements of a yacht port for ship berthing under the extreme water level. For safety consideration, the elevation of the breakwater might need to be properly increased to prevent wave overtopping under such water level. The extended numerical simulation model may provide an effective approach to computing wave heights in a harbor.

A two-step rectification algorithm for airborne linear images with POS data

Rectification for airborne linear images is an indispensable preprocessing step. This paper presents in detail a two-step rectification algorithm. The first step is to establish the model of direct georeference position using the data provided by the Po- sitioning and Orientation System (POS) and obtain the mathematical relationships between the image points and ground reference points. The second step is to apply polynomial distortion model and Bilinear Interpolation to get the final precise rectified images. In this step, a reference image is required and some ground control points (GCPs) are selected. Experiments showed that the final rectified images are satisfactory, and that our two-step rectification algorithm is very effective.

An integrated approach to study of strata behaviour and gas flow dynamics and its application

This paper presents an advanced and integrated research approach to longwall mining-induced strata move- ment, stress changes, fractures, and gas flow dynamics with actual examples of its application from recent studies for coextraction of coal and methane development at Huainan Mining Group in China, in a deep and multi-seam mining environment. The advanced approach takes advantage of the latest techniques in Australia for mine scale geotechnical characterisation, field measurement, monitoring and numerical modelling. Key techniques described in this paper include coal mine site 3D geotechnical characterisation methods, surface deep downhole multi-point extensometers and piezometers for overburden displacement and pore pressure measurements during mining, tracer gas tests for goal gas flow patterns, and advanced numerical modelling codes for coupled coal mine strata, water and gas simulations, and longwall goaf gas ttow investigations. This integrated approach has resulted in significant insights into the complex dynamic imeraction between strata, groundwater, and gas during mining at Huainan Mining Group in recent years. Based on the lindings from the extensive field monitoring and numerical modelling studies, a three-dimensional annular-shaped over-lying zone along the perimeter of the longwall panel was identified for optimal methane drainage during mining.

Modeling, identification and compensation for geometric errors of laser annealing table

In order to improve the process precision of an XY laser annealing table, a geometric error modeling, and an identification and compensation method were proposed. Based on multi-body system theory, a geometric error model for the laser annealing table was established. It supports the identification of 7 geometric errors affecting the annealing accuracy. An original identification method was presented to recognize these geometric errors. Positioning errors of 5 lines in the workspace were measured by a laser interferometer, and the 7 geometric errors were identified by the proposed algorithm. Finally, a software-based error compensation method was adopted, and a compensation mechanism was developed in a postprocessor based on LabVIEW. The identified geometric errors can be compensated by converting ideal NC codes to actual NC codes. A validation experiment has been conducted on the laser annealing table, and the results indicate that positioning errors of two validation lines decreased from ±37 μm and ±33 μm to ±5 μm and ±4.5 μm, respectively. The geometric error modeling, identification and compensation method presented in this work can be straightforwardly extended to any configurations of 2-dimensional worktable.

AN ADVANCED DUAL-FREQUENCY POSITIONING ALGORITHM FOR SATELLITE NAVIGATION RECEIVERS

With the development of the Ground Positioning System (GPS) modernization and the expectable implementation of Galileo, people pay more and more attention to civil applications on multi-frequency signals. This paper proposes a new and advanced positioning algorithm for the dual-frequency satellite navigation receivers, concerning the various influences of all the ranging error sources and taking advantage of the Klobuchar single-frequency ionospheric model. The paper also presents positioning precision provided by the new algorithm. Theoretical analysis and experimental results show that, the new dual-frequency positioning algorithm can achieve higher positioning accu- racy than the single-frequency positioning algorithm and the traditional dual-frequency positioning algorithm.

Television Programs for Teenagers and the Use of Multimodality in Knowledge Popularization

The aim of this work is to study the interaction of spoken words and images that are used within programs targeted to popularize knowledge among teenagers. We will look into the program Bit@bit developed by Television de Catalunya, which is intended to disseminate computer concepts, tools and procedures. In this kind of program, one can find spoken language （on/off screen voices, interviews, etc.）, other oral material （sounds, music, songs）, written language （descriptions, title sequences, inserts and Uniform Resource Locator, or electronic addresses）, and other visual material （film cut images, advertising, other TV programs, cartoons, films, both location or studio images, depicting reality, or computer screens, or logotypes）. The profusion of multimodal elements used in this program helps to keep the young audience＇s attention. The use of references to their world or knowledge, as a target group, is based on interplay among different semiotic strategies. At the same time, the entire program＇s multi-segmentation into short video clips, combined with a fast paced sound track helps its audience to understand the specialized explanations presented. Of all the multimodal wealth that the program presents, we will concentrate only on the relationship between the words and the images （leaving other secondary semiotics to one side）, the main strategy for achieving the objective of transmitting knowledge and winning adolescent audiences.

Study on quality evaluation model in multi-station assembly processes

Based on features of dimension variation propagation in multi-station assembly processes,a new quality evaluation model of assembly processes is established. Firstly,the error source of multi-station assembly system is analyzed,the relationship of dimension variation propagation in multi-station assembly processes is studied and the state equation for variation propagation is constructed too. Then,the feature parameters which influence variation propagation and accumulation in multi-station assembly processes are found to evaluate quality characteristic of the assembly system. Through the derivation of equation on dimension variation propagation,station coefficient matrices which are combined and conversed to determine the max eigenvalue are educed. The max eigenvalue is multiplied by the weight coefficient to establish the quality evaluation model in multi-station assembly processes. Furthermore,assembly variation indexes are proposed to judge of the assembly technology process. Finally,through the practical example,the application of the model and assembly variation indexes are presented.

东西荟萃的黄金盛会

由世界黄金协会主办,上海工艺美术总公司协助,意大利维琴塞贸易发展局、AmbrosianoVeneto银行及维琴塞总商会赞助的“东西荟萃黄金盛会动态展”于1994年11月30日至12月3日在上海锦沧文华大酒店举行。

把青春的美丽留下

把青春的美丽留下图：于广峰文：徐东魏蓉，职业模特，祖籍山东，长在四川。或许正是这南北大融合的奇妙效应，山东人的浓眉大眼、高大身材与四川姑娘娇媚柔和的气质比较完美地结合于她的一身。这天，是七月里少有的凉快天，雨过天晴，清风徐徐，令人心平气爽。魏蓉一身仔...

A Stochastic Model on One-Unit Repairable Systems with Multiple Degenerative States

This paper studies a maintenance model for an one-unit degenerative system with multiple failure states based on the proportional hazards and proportional reversed hazards models. The authors investigate how the variation of system configuration parameters have an impact on both operating and repair times and hence the system performance. Furthermore, the authors also derive the explicit expression for the long-run average cost per unit time. An algorithm to locate the optimal number of repairs in a renewal cycle is discussed as well.

The evolution of multi-component visual signals in darters （genus Etheostoma）

As complex traits evolve, each component of the trait may be under different selection pressures and could respond independently to distinct evolutionary forces. We used comparative methods to examine patterns of evolution in multiple components of a complex courtship signal in darters, specifically addressing the question of how nuptial coloration evolves across different areas of the body. Using spectral reflectance, we defined 4 broad color classes present on the body and fins of 17 species of freshwater fishes （genus Etheostoma） and quantified differences in hue within each color class. Ancestral state reconstruction suggests that most color traits were expressed in the most recent common ancestor of sampled species and that differences among species are mostly due to losses in coloration. The evolutionary lability of coloration varied across body regions; we found sig- nificant phylogenetic signal for orange color on the body but not for most colors on fins. Finally, patterns of color evolution and hue Of the colors were correlated among the two dorsal fins and between the anterior dorsal and anal fins, but not between any of the fins and the body. The observed patterns support the hypothesis that different components of complex signals may be subject to distinct evolutionary pressures, and suggests that the combination of behavioral displays and morphology in communication may have a strong influence on patterns of signal evolution .

Numerical modeling of simultaneous hydraulic fracturing in the mode of multi-well pads

In order to investigate propagation regularity of hydraulic fractures in the mode of multi-well pads, numerical modeling of simultaneous hydraulic fracturing of multiple wells was conducted. The mathematical model was established coupling rock deformation with fluid flow in the fractures and wellbores. And then the model was solved by displacement discontinuity method coupling with implicit level set method. The implicit method was based on fracture tip asymptotical solution and used to determine fracture growth length. Simulation results showed that when multiple wells were fractured simultaneously, adjacent fractures might propagate towards each other, showing an effect of attraction other than repulsion. Fracture spacing and well spacing had significant influence on the propagation path and geometry of multiple fractures. Furthermore, when multiple wells were fractured simultaneously, stress reversal regions had a large area, and stress reversal regions were distributed not only in the area between fractures but also on the outside of them. The area of stress reversal regions was related to fracture spacing and well spacing. Results indicated that multi-well fracturing induced larger area of stress reversal regions than one-well fracturing, which was beneficial to generating complex fracture network in unconventional reservoirs.

Modeling and Doppler measurement of X-ray pulsar

Generally,the Doppler caused by the velocity of the detector leads to distortion of the integrated profile of the X-ray pulsar,on the contrary,if the distortion can be used to measure the Doppler,then the velocity of the detector is easy to be solved.In view of this,the correlation of the periodic error arise from the Doppler and the integrated profile was analyzed,then,based on the Poisson distribution model of the X-ray Pulsar,a new signal model and the concept of the profile entropy was defined.Furthermore,the directly cumulated profile of the signal was modeled with the Doppler as a parameter,and then the Doppler was solved via optimal method.Simultaneously,the performance of phase measurement based on this method was studded.The analysis shows that this method can get rid of the periodic error due to the discrete sampling,and can obtain continuous phase estimation.The experiment verification shows the consistency of the theory and the experiment.