C#.Net平台下制图系统的底层开发

简要分析制图系统所应具备的基本系统功能,并采用组件式构架的思想,在C#.NET环境下组织计算机制图系统的底层开发,实现计算机制图系统的基本功能。对系统开发的核心问题如系统框架设计,系统结构设计等内容进行探讨。系统采用组件式开发的思想,与当今主流的软件开发方式接轨。     

Preparation and crystallization action of SiO2 -Al2O3 -CaO-ZnO-R2O porous glass-ceramics

Using powder-sintering method,SiO2-Al2O3-CaO-ZnO-R2O porous glass-ceramics were produced for analysis. Five samples with different SiO2 /CaO ratios were used in the research. The mechanical properties, microstructures and textures of porous glass-ceramics are investigated by using differential thermogravimetric analysis/differential thermal analysis ( TGA/SDTA) ,X-ray diffraction ( XRD) ,and scanning electron microsco- py ( SEM) . The activity energy of crystallization ( E) and crystallization kinetics parameter ( k) were calculated based on the modified JMA equation. The Avrami parameter n was obtained according to Augis-Bennett function. The results show that the k value of No. 1 sample ( SiO2 /CaO = 61∶ 18) is the largest among all samples, which tends to crystallize more easily,and crystallization processes of all samples are observed bulk crystallization. The main crystal phase observed is parawollastonite ( clinorhombic system) with puncheon shape. Poreforming agents decomposed at 100 - 500 ℃ form a large number of closed pores with micron dimension and several semi-open pores distribute uniformly in the glass-ceramics matrix. This work may be expected to be favorable for industrial scale applications of porous glass-ceramics in the field of building thermal insulation.     

电磁管道抗垢装置的功放及回馈电路关键技术

分析比较了超声波防垢、机械去垢、管道化学酸洗、管道高压水射流清洗和电磁防垢的方法和效果。利用电磁防垢的防垢、除垢、杀菌和灭藻的功能原理,研制了嵌入式音频电磁共振管道抗垢装置。音频功率放大器件是装置的关键部分,既保证了足够的功率输出,又具有短路保护和过热保护作用。电路设计上,根据推动负载线圈功率信号的特点,将常规的线性功率放大电路改进成比较开关电路,有效降低了功放芯片的自身损耗。装置还通过线性光耦回馈负载线圈上的信号,进行峰值检测,经过微处理器运算后输出最佳频率,优化了管道抗垢去垢功效。     

Ug注射模设计系统在模具设计与制造中的应用

采用Ug Mold Wizard系统设计注塑模的工作流程,以及Ug Mold Wizard注射模具设计相关的模块,探讨了Ug Mold Wizard进行注塑模设计的具体设计流程和KBE知识工程的调用过程。借助计算机辅助扣板塑料模具设计及制造实例,得出Ug Mold Wizard在注塑模设计中的优化调用模具设计方案和仿真过程。该系统在注射模具设计与制造中的应用促进注射模具设计与制造的无纸化和产品短周期化进程。     

Numerical simulation study on the influence of the ground stress field on the stability of roadways

We adopt the concept of generalized plane strain to model a roadway in a stress field.This can avoid limitations caused by simplifying the stress analysis as plane strain.FLAC3D was used to investigate the maximum tensile stress and displacement of a roadway in a known stress field for angles,α,between the roadway axial direction and the maximum principal stress of 0°,30°,45°,60° and 90°.This theory was applied to the analysis of an engineering case.The results indicate that stress and displacement of the surrounding rock increase as the angle,α,increases.This provides some significant guidance for a reasonable layout of roadways in a known stress field.     

Application of structural curvature of coalbed floor on CBM development in the Zaoyuan block of the southern Qinshui Basin

Based on controls of structural style and the position in coalbed methane(CBM)development,we used a method of curvatures to study its relations with CBM development parameters.We calculated structural curvatures of contours of the No.3coal seam floor of the Shanxi Formation in the Zaoyuan block of the Qinshui Basin and analyzed its relations with development parameters of coalbed methane wells.The results show that structural curvature is negatively related to coal reservoir pressure,while positively related to permeability.With an increase in structural curvature,the average production of coalbed methane wells increases at first and then decreases,reaching the highest production at 0.02 m-1 of structural curvature.Therefore,structural curvature can be an important index for potential evaluation of coalbed methane development and provide a basis for siting coalbed methane wells.     

Numerical simulation on bolted rock joint shearing performance

A Double Shear Model(DSM)was used in a numerical simulation on bolted rock joint shearing performance.An entire bolt deformed as the letter"U"under a shear load between two joints.Near the bolt-joint intersection,the bolt partly deformed as the letter"Z".There were two critical points along the bolt: one was at the bolt-joint intersection with zero bending moment and the other at the maximum bending moment(plastic hinge)with zero shear stress.The blocks on two sides slid along the bolt as it deformed.A separation area was found between the two joint contact surfaces of the middle rock block and sided block.This area of separation was related to bolt diameter and external forces.We assume that this area is related to the work of external forces.Further research is needed.     

板式空冷器导流板式液体分布器结构与流动规律研究

对导流板式液体分布装置的结构提出设计方法并进行了数学描述,推导得出了结构压降公式。采用CFX对该结构进行流场模拟,流场显示入口流体的分布。提出的结构设计方法和压降公式对于板式空冷器液体分布器的设计具有一定的理论指导意义。     

基于AdaBoost算法的VOD代理数据分布策略

提出一种面向园区网VOD代理系统的节目分布策略,首先构建基于BP神经网络的弱分类器并采用AdaBoost算法将其提升为强分类器,然后基于该分类器对系统中的节目按流行度高低进行分类,再根据分类结果采用基于分组和点播率的方法对系统中的代理服务器进行文件分布.该策略充分利用用户点播行为中蕴含的信息,并具有执行结构简洁,易于实施的优点,仿真实验结果表明该策略能有效提高代理服务器的利用率.     

基于nRF24LE1的无线数据传输系统实现

nRF24LE1是2.4 GHz ISM微波频段的低成本、高性能嵌入式微处理器智能射频收发器家族中的成员.设计了基于射频收发芯片nRF24LE1的无线数据传输系统,给出了射频收发系统主要部分的硬件电路图和软件收发程序流程图,重点探究了nRF24LE1在Enhanced ShockBurstTM收发模式下的无线数据收发过程和实现.室外测试实现了50 m以上的远距离无线数据传输,具有功耗低、传输距离远及性能稳定等优点,可广泛应用于多种无线数据传输的场合.