A plate capacitor model of the EDM process based on the field emission theory

The electrical discharge machining (EDM) process is, by far, the most popular amongst the non-conventional machining processes. The technology is optimum for accurate machining of complicated shapes in hard materials, required in the modern industry. However, although a lot of EDM machines are widely applied for many years, fundamental knowledge of the process is still limited. The complex nature of the process involves simultaneous interaction of thermal, plasma temperature and electromagnetism factors, which makes the machining process modeling very difficult. In this paper, based on the analysis of the electric discharge machining (EDM) process, a plate capacitor model is constructed to describe the discharging process in a pulse time. The whole EDM process is divided into four stages, successively as interelectrode electric-field establishment, electric discharge channel formation, stable EDM and deionization, the interaction of each stage and the distribution function of EDM energy are deduced using the field electron emission theory. For the purpose of analyzing the effect of the single factor, a set of machining through-hole experiments were carried out and investigated. The study shows that critical electric-field intensity and the effective discharging time rate play major roles on the improvement of machining efficiency; the model can explain the differences of machining efficiency using different materials of tool pole and different EDM parameters; and the theoretical results are concordant with the experimental data well.     

基于边缘检测的影像多线自动测量算法

介绍了基于小波变换的边缘检测算法。利用此算法提出了一种影像多线自动测量算法,给出了此算法的步骤。结果表明,该算法达到了较好的测量效果。最后讨论了该算法的不足之处。     

正确处理综合单价下的桩基工程量争议

本文主要根据参建方对综合单价下桩基工程量计算的争议,从计价规范、05定额及有关权威部门解释等角度出发,提出正确的分析方法和处理意见。     

An efficient luminescent bonding-type Eu-containing copolymer as a red-emitting phosphor for fabrication of LED

A luminescent europium-containing copolymer, poly(MMA-MA-co-Eu(TTA)₂phen), was synthesized though a reaction of EuCl₃, 1,10-phenanthroline (phen), α-thenoyltrifluoroacetone (TTA) with copolymer of maleic acid (MA) and methyl methacrylate (MMA). The copolymer was characterized by FT-IR, UV–vis, gel permeation chromatograph (GPC), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis. The Eu-copolymer phosphor exhibited high thermal stability and excellent photoluminescence properties, appropriate CIE chromaticity coordinates for red and a quantum yield of 24% under near-UV light excitation. It emitted intense red light at 613 nm under UV excitation at room temperature, which is attributed to the ⁵D₀ → ⁷F₂ transition of Eu(III) ions. An intense red-emitting light-emitting diode (LED) was fabricated by combining poly(MA-MMA-co-Eu(TTA)₂phen) with a 395 nm-emitting InGaN chip. The results indicate that the Eu-copolymer phosphor may act as a red component for fabrication of white LEDs.     

实施《JJG795-2004耐电压测试仪试行检定规程》的几点探讨

本文对于JJG795-2004《耐电压测试仪试行检定规程》中有关耐压测试仪输出电压、击穿报警电流误差及电压持续保持时间的检定方法谈几点探讨意见。     

浅淡漳州市住宅外墙保温施工

漳州的气候条件对于建筑节能来说,主要是夏季隔热的问题,本文对漳州目前采用的住宅外墙保温施工的问题进行了粗浅的探讨。     

居住空间中玻璃材质的选择与运用探议

玻璃凭借其多样的材质特性，在室内设计领域越来越受到追捧和重视，通过对不同类别的玻璃材质属性进行分析，本文针对其在室内居住空间不同风格及区域的应用加以阐述。     

漳州市急救中心基础设计及处理

本文结合某工程的地下室与基础设计实例，通过几种基础设计方案比选，经济合理地解决了因地下室局部往一个方向扩大而造成的基础偏心，着重探讨采用基础局部超挖，调整基底形心，并取得了良好的效果。     

Characterization of vitreous enamel–steel interface by using hot stage ESEM and nano-indentation techniques

In this study, phase transformation of the vitreous enamel and the interface steel–enamel during firing was analyzed. The thermal transformation of vitreous coating on steel was observed “in situ” with an environmental scanning electron microscopy and the mechanical properties of the steel–enamel interface were studied by using a nano-indenter. The interface reactions and the resulting structure can strongly influence the adhesion mechanism between glass coatings and the metal substrate. An in-depth investigation and structural characterization was therefore performed to define the correlation between interface morphology and the final chemical and mechanical properties of the enamel–steel interface.