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101.
罗新 《电脑学习》2006,(5):48-49
本文给出了一个应用RSS的信息发布系统的设计过程和主要代码.  相似文献   
102.
Regional Geological Information System combines the multi-dimensional and dynamic spatial information into an integrated spatial information system. 3D geological modeling and its preprocessing or post-processing are the most difficult problems for constructing the system. Based on the current 3D GIS technique, some basic problems in establishing the system are discussed in this paper, including 3D spatial data model, 3D geological modeling, and visualization of 3D geological data. A kind of 3D vector data model based on boundary representation for geological object and its topology was developed in order to model and visualize complex geological structures. In addition, some key techniques are pointed out for further study.  相似文献   
103.
Compared with the single sulphurating treatment, the duplex treatment of nitrocarburizing-sulphurating can more effectively improve the properties of steel such as friction-reducing, wear resistance and anti-scuffing. Under the same processing parameters, the sulphide layers were fabricated on the surface of CrMoCu alloy cast iron by single ion-sulphurating treatment and nitrocarburizing-sulphurating duplex treatment, respectively. Through the analysis of the sulphide, the effect of the nitrocarburizing on the fabrication of the sulphide layer was investigated. And the result shows that the fabrication of sulphide layer is promoted by the nitrocarburizing treatment.  相似文献   
104.
对63MN五坐标数控快锻机在自由锻和恒温锻不同的工艺过程进行分析,根据压机设备压力高、流量大的特点,进行系统的优化设计。并对降低噪声、抗污染、保证系统可靠性、实现系统的高精度、高响应等要求,提出了合理的设计方案。  相似文献   
105.
升温速率对金属熔化和过热的影响   总被引:1,自引:0,他引:1  
采用分子动力学方法和QSC(Quantum Sutton-Chen)力场研究了升温速率对金属银和金属铅的熔化和过热行为的影响。研究结果表明,升温速率对金属银和铅的熔化和过热行为有很大影响,随着升温速率的升高,金属的熔点有所升高。高的升温速率会导致金属体系内部无序化程度增加,降低了熔化相变的能垒。升温速率导致的银和铅完美晶体的过热极限分别为1450K和800K。  相似文献   
106.
Fluorinated amorphous carbon films (a-C:F) were prepared at different temperatures using a microwave electron cyclotron resonance chemical vapor deposition (ECR-CVD) reactor with CHF3 and C2H2 as source gases. Films were annealed at 500℃ in vacuum ambience inorder to investigate the relationship of their thermal stability, optical and electrical propertieswith deposition temperature. Results indicate that the films deposited at high temperature have a less CFx bonding and a more cross-linking structure thus a better thermal stability. They also have a lower bandgap, higher dielectric constant and higher leakage current.  相似文献   
107.
电力系统全停后的黑起动方案研究,是保证电力系统安全运行的重要课题.围绕甘肃电网的网架结构特点,研究提出了甘肃电网的黑起动方案.通过计算分析,对甘肃电网黑起动过程中存在的问题提出了解决的对策.  相似文献   
108.
109.
A novel principle “electret” microphone, i.e., floating electrode electret microphone, is proposed and implemented in this study. Single-chip fabrication and corrugation technique are used in the design and fabrication of the microphone. The floating electrode is encapsulated by highly insulated materials to ensure that there is no electric-leakage passage between the floating electrode and the electrodes of the microphone. Net-free electronic charges (not “bonded” charges as in traditional electret) in the floating electrode can excite the electric field, which is similar to that of the traditional electret. The floating electrode can be easily charged by use of the “hot” electron technique, available using the avalanche breakdown of the p+-n junction. Therefore, the electret microphone is rechargeable, which can greatly increase the lifetime of the device. The preamplifier has been on-chip integrated in a junction-field-effect transistor (JFET) source-follower type with resistors by use of ion implantation. Electret charges are banded in a deep potential trap, thus, this microphone can operate at a high temperature (as high as 300°C) and has high stability and reliability. Experiments show that the prototype has a 3-mV/Pa sensitivity and a larger than 21-kHz frequency bandwidth in a 1 mm ×1-mm diaphragm area. Microphone performance can be further improved by optimized process and design. The fabrication is completely integrated-circuit (IC) compatible, hence, the microphone shows promise in integrated acoustic systems  相似文献   
110.
LiFePO4 cathode material was synthesized by a solid-state reaction using doping several elements (Nb5 ,Zr4 ). The starting materials were mixed with a high-efficient sander and treated thermally under flowing N2. The samples were characterized by X-ray diffraction (XRD), field-emission gun electron microscopy (FEG), and their electrochemical performance was investigated in the term of cycling behavior. Room temperature discharge capacity about 140.6 mA·h·g-1 was obtained at C/5 rate.  相似文献   
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