OPTIMIZATION OF ACOUSTIC IMPEDANCE，GEOMETRIC STRUCTURE AND OPERATING CONDITION OF LINERS MOUNTED IN ENGINE DUCT

Acoustically absorptive treatment in aircraft engine nacelle is an essential part of the overall aircraft noise reduction effort. The investigation on the optimization of multi-liners plays an important role in noise reduction. Based upon the mode analysis method of sound propagation in a circular duct with multiple liners, a flexible tolerance method is used to optimize the acoustic parameters(impedance), geometric structure parameters(such as open area ratio, cavity depth and hole diameter) and operating condition parameters(such as blade passing frequency). The mathematical models for these kinds of optimization are presented here. The optimum values of the design variables are determined when the in-duct sound suppression approaches a maximum. It can be derived from the optimum results that the emphasis of the engineering optimization design of the perforated plate honey-comb structure should be placed on the optimum choice of the open area ratio and cavity depth. Some reference criteria for the engineering design of the multi-linings are also provided.

ON-LINE STATE PREDICTION OF ENGINES BASED ON FLAT NEURAL NETWORK

A flat neural network is designed for the on line state prediction of engine. To reduce the computational cost of weight matrix, a fast recursive algorithm is derived according to the pseudoinverse formula of a partition matrix. Furthermore, the forgetting factor approach is introduced to improve predictive accuracy and robustness of the model. The experiment results indicate that the improved neural network is of good accuracy and strong robustness in prediction, and can apply for the on line prediction of nonlinear multi input multi output systems like vehicle engines.

A remarkable progress in breeding new rice line through gene engineering

Much progress has been made in the research of breeding new rice line through gene engineering by Life Science College of Fudan Univ, Shanghai, and the Plant Science Res Inst of Shanghai Acad of Agri. It was the first time internationally that the research adopted a man-combined gene, taking agrobacterium as car-

Maintenance Engineering Department of China Eastern Jiangxi Branch Establishing the First Line of Defense for Safe Flight

Maintenance Engineering Department of China Eastern Jiangxi Branch has 130 employees and manages four Airbuses A319 and two A320s. seen from the ratio of man to plane, it is the lowest among China Eastern branches (subsidiaries). Due to the requirement of the air market, the six planes are arranged separately in Nanchang, Shanghai, Fuzhou and Ningbo, thus the six planes are maintained in four places, which is unique among China

基于ArcGIS Engine的铁路线路GIS的构建与实现

传统的铁路地理信息系统多采用二维平面方式进行构建,无法再现真实世界。将三维GIS技术应用在铁路信息化系统建设中,进行有益的探索。提出铁路线路三维GIS的构建框架,分析数据库和系统功能模块体系的设计思想,并探讨基于ArcGIS Engine技术,建设铁路线路三维GIS的实现方法和关键技术。

基于Pro/ENGINEER Wildfire的翅片成形刀具设计

散热片是汽车空调器的重要组成部分。阐述了利用Pro/ENGINEER Wildfire Part模块进行翅片成形刀具渐开线齿轮基体设计的过程,并重点分析了刀具线切割加工轨迹的生成方法,对复杂曲面零件的造型和曲面分析有参考价值。

基于ArcGIS Engine的水下间断等高线自动连接研究

本文利用ArcGIS提供的数据分析和数据管理功能对不连续的水下等高线自动连接问题进行了研究。ArcGIS Engine作为ESRI公司最新推出的面向开发的嵌入式组件,具有高效便捷的特点,由于其开发时完全脱离了ArcGIS桌面平台,因而为用户提供了一个可供选择的,有针对性的,低成本的GIS应用选择。本文对水下地形等高线的断线自动连接问题应用ArcGIS Engine进行了研究实验,阐述了使用该技术编程的具体过程,实验结果证明了本文方法的有效性和实用价值。

Deformation-based freeform feature reconstruction in reverse engineering

For reconstructing a freeform feature from point cloud, a deformation-based method is proposed in this paper. The freeform feature consists of a secondary surface and a blending surface. The secondary surface plays a role in substituting a local region of a given primary surface. The blending surface acts as a bridge to smoothly connect the unchanged region of the primary surface with the secondary surface. The secondary surface is generated by surface deformation subjected to line constraints, i.e., character lines and limiting lines, not designed by conventional methods. The lines are used to represent the underlying informa-tion of the freeform feature in point cloud, where the character lines depict the feature’s shape, and the limiting lines determine its location and orientation. The configuration of the character lines and the extraction of the limiting lines are discussed in detail. The blending surface is designed by the traditional modeling method, whose intrinsic parameters are recovered from point cloud through a series of steps, namely, point cloud slicing, circle fitting and regression analysis. The proposed method is used not only to effectively and efficiently reconstruct the freeform feature, but also to modify it by manipulating the line constraints. Typical examples are given to verify our method.

基于OpenCV和ArcGIS Engine的墙体中线自动提取在不动产测绘中的应用

在不动产测绘业务中,无论是房产预测绘还是实测绘,内业过程中都需要基于建筑单体的CAD电子图纸来获取墙体中线。传统的做法是利用AutoCAD软件的标注功能来逐边画取,这种做法的优点是画取的边线精度较高,但效率低下,占据了房产测绘内业的大部分工作量。为提高房产测绘内业的作业效率,本文采用二值化、骨骼化等算法,基于OpenCV和ArcGIS Engine技术,实现了CAD墙体中线的自动提取,对不动产测绘内业的作业流程进行了优化。实验结果表明,本文采用的方法在不动产测绘内业生产中具有一定的实用价值。

A Domain Engineering Approach to Increase Productivity in the Development of a Service for Changes Notification of the Configuration Management Database

This paper presents a domain engineering approach to build a software product line that supports the change notification service in a Configuration Management Database (CMDB) according to the Information Technology Infrastructure Library (ITIL) best practices. For the development of this product line, the proposed approach makes use of a construction of products methodology by analogy: this is a new notation which reports the variability of the products, obtaining metrics as important as the number of products and uses a language that enables, by means of the flexibilization of a product and the development of some generators, to build the rest of the product line. In addition the paper offers a standard for the analysis and design of the CMDB as well. Finally, the paper presents an economic model for the product line, where the profitability and productivity of the proposed solution are analyzed.

Snow disaster characteristics in Palongzangbu River Basinand mitigation countermeasures for road engineering

The Palongzangbu River Basin contains the highest number of maritime province glaciers in China. There are 130 glacial lakes, 64 snow avalanche sites and 28 glacial debris flow gullies distributed within the basin. Snow disasters play a controlling role in the Sichuan-Tibet Highway construction, due to the terrain’s special characteristics of high altitude and large height differential. Segmentation mitigation countermeasures for the Sichuan-Tibet Highway are presented based on snow disaster severity level and damage mode of the road. In the Ranwu to Midui section, snow avalanches are regional disasters, so the line should be placed in sunny slopes. In the Midui Gully to Yupu section, the line should be placed in shady slopes and at higher elevations to reduce the risk of glacial lake outburst. In the Yupu to Guxiang section, all three snow disasters are minimal. In the Guxiang to Tongmai section, glacier debris flows are the major threat, thus the road should be placed in shady slopes.

基于Engineering Base和Excel的烟草制丝生产线电控系统的快速设计

在分析生产线电控系统图纸设计特点的基础上,以烟草制丝生产线电控图纸的模块化设计为例,以Engineering Base软件为平台,给出了自动化生产线电控模块的拆分方法和模块建库方案,并以新电控项目全模块化Excel配置设计为目标,设计了基于Excel的项目设备统计表和电控模块配置表。然后通过VBA二次开发,解析上述Excel表单,以直接从模块库中调用已有电控模块和利用图形符号及模板通过Excel配置表组合出新的电控模块两种模块调用方式,实现Excel项目设备统计表所描述的电控模块的组合,从而以全模块化的方式完成自动化生产线的电控图纸设计。实践证明该方法能显著提高设计效率。

Application of 2-D and 3-D Geo-electrical Resistivity Tomography and Geotechnical Soil Evaluation for Engineering Site Investigation:A Case Study of Okerenkoko Primary School,Warri-Southwest,Delta State,Nigeria

In the design of building structures,joint efforts must be decided to resolve the depth of competent layers across the intended site to safeguard the durability of civil engineering structures and to avert the disastrous consequences of structural failure and collapse.In this study,an integrated methodology that employed DC resistivity tomography involving 2-D and 3-D techniques and geotechnical-soil analysis was used to evaluate subsoil conditions for engineering site investigation at Okerenkoko primary school,in the Warri-southwest area of Delta State,to adduce the phenomena responsible for the visible cracks/structural failure observed in the buildings.The results obtained brought to light the geological structure beneath the subsurface,which consists of four geoelectric layers identified as topsoil,dry/lithified upper sandy layer,wet sand(water-saturated)and peat/clay/sandy clayey soil(highly water-saturated).The deeply-seated peat/clay materials(ρ≤20Ωm)were delineated in the study area to the depths of 17.1 m and 19.8 m from 2-D and 3-D tomography respectively.3-D images presented as horizontal depth slices revealed the dominance of very low resistivity materials i.e.peat/clay/sandy clay within the fourth,fifth and sixth layers at depths ranging from 8.68-12.5 m,12.5-16.9 m and 16.9-21.9 m respectively.The dominance of mechanically unstable peat/clay/sandy clay layers beneath the subsurface,which are highly mobile in response to volumetric changes,is responsible for the noticeable cracks/failure detected on structures within the study site.These observations were validated by a geotechnical test of soil samples in the study area.Atterberg’s limits of the samples revealed plasticity indices of zero.Thus,the soil samples within the depth analyzed were representatives of sandy soil that does not possess any plasticity.The methods justifiably provided relevant information on the subsurface geology beneath the study site and should be appropriated as major tools for engineering site assessment/geotechnical projects.

Pro／ENGINEER高级阵列的探讨

在大多数CAD软件中都有阵列这个命令，一般软件的阵列操作非常简单。作为功能强大的三维造型软件，Pro／ENGINEER的阵列功能也非常强大，但是大多数人只知道Pro／ENGINEER阵列的一些初级应用，碰到复杂点的阵列就转而想别的办法实现。本文主要对Pro／ENGINEER的高级阵列功能进行深入探讨，通过一系列实例来体现Pro／ENGINEER与其它CAD软件在阵列方面的巨大优势。

Feasibility Research on Application of a High Frequency Induction Heat to Line Heating Technology

The purpose of this paper is to investigate the feasibility of high-frequency induction heat for the line heating process through a series of experimental studies and numerical calculations. The results show that the heating temperature of induction heating meets the demands of steel plate bending, and the deformation of a steel plate heated by induction heating can achieve the same effect as flame heating. Meanwhile, the finite element model of moving induction heating of the plate is developed, and the comparison of the residual strain fields and transverse shrinkage between these two kinds of heating shows that great similarity has been achieved.

Flexible Scanning Method by Integrating Laser Line Sensors with Articulated Arm Coordinate Measuring Machines

Measuring and reconstructing the shape of workpieces have been considered as a fundamental step in both reverse engineering and product quality control.Owing to increasing structural complexity of recent products,measurements from multiple directions are typically required in current scanning techniques.Specifically,the plane structured light can be applied to measure one area of a part at a time,with an additional algorithm required to merge the collected data of each area.Alternatively,the line structured light sensor integrated on CNC machines or CMMs could also realize multi-view measurement.However,the system needs to be repeatedly calibrated at each new direction.This paper presents a flexible scanning method by integrating laser line sensors with articulated arm coordinate measuring machines(AACMM).Since the output of the laser line sensor is 2D raw data in the laser plane,our system model introduces an explicit transformation from the 2D sensor coordinate frame to the 3D base coordinate frame of the AACMM(i.e.,the translation and rotation the of the 2D sensor coordinate in the sixth coordinate system of AACMM).To solve the model,the“conjugate pairs”are proposed and identified by measuring a fixed point(e.g.,a sphere center).Moreover,a search algorithm is adopted to find the optimal solution,which noticeably boosts the model accuracy.The experimental results show that the error of the system is about 0.2 mm,which is caused by the error of the AACMM,the sensor error and the calibration error.By measuring a complicated part,the proposed system is proved to be flexible and facilitate,with the ability to measure a part expediently from any necessary direction.Furthermore,the proposed calibration method can also be used for robot hand-eye relationship calibration.

Application of Line Boundary Technique to 2D Tidal Current Simulation

To deal with the problems concerning the shore boundary, moving boundary and engineering boundary which are encountered frequently in 2D tidal current simulation by the finite difference method, the concept of line boundary is introduced and studied here, and then the line boundary technique in common use is proposed in this paper. Analysis of some calculation cases shows that this technique is practical, effective, and simple in 2D tidal current simulation involving different boundaries.

Analysis of the Behavior of a HV AC Line during an Atmospheric Discharge and Evaluation of the Spatio-Temporal Distribution of the Lightning Current Wave

In high voltage networks for the transport of electrical energy, lightning, a phenomenon as dangerous as it is impressive, with an easily recognizable form, can affect a power line by striking either a phase conductor, a tower or a guard cable, thus causing more dangerous and constraining stresses on the lines for its proper operation. Thus, this article aims to analyze the behavior of a HV line during an atmospheric discharge and assess the spatial and temporal distribution of the lightning current wave. For this purpose, the generalities on the transmissible power in case of link without resistance and the modeling of the atmospheric surge propagation established on the basis of the theory of the lines with distributed constants implementing the wave equation known as the Alembert equation have been developed. Through this research, we are interested in the study of the space-time distribution of the lightning current wave in order to model the radiated electromagnetic field and to examine the influence of the atmospheric discharge induced overvoltage on the transportable power of a High Voltage AC Transmission line, for a good selective protection in order to illuminate the parasites. The 2D simulation based on engineering and “Transmission Line” models have been developed as well as the verification of the coherence of the different models, by comparing the fractal dimensions of the program results with those of the experimentally obtained figures.

Analysis of Potential Failure Modes in an Assembly Line by Fuzzy Expert Systems

The failure modes and effects analysis （FMEA） is widely applied in manufacturing industries in various phases of the product life cycle to evaluate the system, its design and processes for failures that can occur. The FMEA team often demonstrates different opinions and these different types of opinions are very difficult to incorporate into the FMEA by the traditional risk priority number model. In this paper, for each of the Occurrence, Severity and Detectivity parameters a fuzzy set is defined and the opinion of each FMEA team members is considered. These opinions are considered simultaneously with weights that are given to each individual based on their skills and experience levels. In addition, the opinion of the costumer is considered for each of the FMEA parameters. Then, the Risk Priority Numbers （RPN） is calculated using a Multi Input Single Output （MISO） fuzzy expert system. The proposed model is applied for prioritizing the failures of Peugeot 206 Engine assembly line in IKCo （Iran Khodro Company）.