铁离子对硝酸铵热行为的影响

用加速量热仪研究铁离子对硝酸铵热稳定性的影响,并将其结果与含氯离子硝酸铵的热分解实验结果进行比较。结果表明,铁离子也有很强的催化能力,使硝酸铵的起始分解温度降低约60℃。在恒温条件下的试验结果也证明铁离子对硝酸铵具有催化作用。根据得到的ARC数据,对含铁离子硝酸铵的热分解进行动力学计算,运用最概然机理函数法得到了最可能的机理函数为f(α)=1-,α含铁离子硝酸铵的活化能E=195.41 J/m o l。结果表明,硝酸铵中一旦混入铁离子,其热稳定性将会降低。     

New stability index for short circuit transfer mode in GMAW process using acoustic emission signals

Abstract

A new index for the analysis of stability of GMAW processes taking as a base the acoustic emission generated by the arc during the short circuit metal transfer is presented in the present work. The incidence of parameters of process is analysed in the indices of the acoustic emission signal, as well as its influence on the stability, evaluated through a new proposed index. The results obtained allowed having a relationship between acoustic signals and arc voltage signals, and demonstrated the validity of proposed index of acoustic emission for analysis of stability of GMAW process. The obtained results were then compared with other classic stability analysis methods based on statistical analysis of temporal signals of arc voltage. Finally a statistical analysis for the validation of the obtained experimental results was carried out. As a result of the investigation, the effectiveness of the method proposed as a new way for the analysis of stability is demonstrated. The research can contribute towards a new standard to evaluate the stability in welding processes.     

Double layer SiNx:H films for passivation and anti-reflection coating of c-Si solar cells

In this report, we present a cost effective simple innovative approach to fabricate double layer anti-reflection (DLAR) coatings using a single material which can provide high qualities of passivation and anti-reflection property. Two layers of SiN_x:H films with different refractive indices were deposited onto p-type c-Si wafer using plasma enhanced chemical vapor deposition reactor by controlling the NH₃ and SiH₄ gas ratio. Refractive indices of top and bottom layers were chosen as 1.9 and 2.3 respectively. The effect of passivation at the interface was investigated by effective carrier lifetime, hydrogen concentration and interface trapped density (D_it) measurements. The optical characteristic was analyzed by reflectance and transmittance measurements. A superior efficiency of 17.61% was obtained for solar cells fabricated with DLAR coating when compared to an efficiency of 17.24% for cells with SLAR coating. Further, J_sc and V_oc of solar cell with DLAR coating is increased by a value of ~ 1 mA/cm² and 4 mV respectively than cell with SLAR coating.     

A study on the effects of ESFAS STI modification on the unavailability of ESF actuated components

The nuclear industry has made so great efforts to attain safe and economically viable Nuclear Power Plants all over the world. Probabilistic Safety Assessment (PSA) applications are required now more than ever in order to operate Nuclear Power Plants.In this paper, the unavailability model of Engineered Safety Feature (ESF) actuated components, which is part of the Korean Standard Nuclear Power Plant (KSNPP) PSA model, is used to analyze the effects of Surveillance Test Interval (STI) extension of Engineered Safety Feature Actuation System (ESFAS) on the unavailability of the ESF actuated components.To develop a more accurate and realistic PSA model, the loop controller modules of Plant Control System (PCS) are also modeled on the KSNPP PSA model. The fault tree developed by each ESF actuated component includes the component failure, ESFAS signal failure, and loop controller module failure of PCS. When the ESFAS STI is extended from one month to three months, the unavailability of ESF actuated components partially increased by 10%. This shows the STI extension of ESFAS has minor effects on the unavailability of the ESF actuated components. The effects of ESFAS STI extension of KSNPP on the unavailability of the ESF actuated components as well as Core Damage Frequency (CDF) and Large Early Release Frequency (LERF) is less than expected. That result indirectly indicates that the ESFAS in KSNPP is designed well enough to extend the ESFAS STI.     

天津精细化工区可发展项目研究

天津是我国重要的化工基地之一,但是高端品种短缺,产品差异化程度较低成为突出问题,面临着产业转型和升级,精细化工做为高附加值产业越来越成为主要发展方向。通过对国内及天津市主要化学品情况的分析,发展电子化学品、ACR、BOPA等项目是可行的。     

Screens

The screen is a recurring element in the work of Niall McLaughlin Architects . Environmental considerations have provided the opportunity for inclusion of the screen in built works, but it has been embraced by them for its geometric and material qualities, as well as the play it affords with light. The practice has relished the transformative powers of inserting everyday found objects into the screens to provide an additional level of surprise and delight. Copyright © 2008 John Wiley & Sons, Ltd.     

水泵过流部件汽蚀麻面的修复

文章介绍水泵叶片、泵壳内壁汽蚀麻面采用ARC高分子复合材料修复的方法和效果.     

A standards‐based Grid resource brokering service supporting advance reservations,coallocation, and cross‐Grid interoperability

The problem of Grid‐middleware interoperability is addressed by the design and analysis of a feature‐rich, standards‐based framework for all‐to‐all cross‐middleware job submission. The architecture is designed with focus on generality and flexibility and builds on extensive use, internally and externally, of (proposed) Web and Grid services standards such as WSRF, JSDL, GLUE, and WS‐Agreement. The external use provides the foundation for easy integration into specific middlewares, which is performed by the design of a small set of plugins for each middleware. Currently, plugins are provided for integration into Globus Toolkit 4 and NorduGrid/ARC. The internal use of standard formats facilitates customization of the job submission service by replacement of custom components for performing specific well‐defined tasks. Most importantly, this enables the easy replacement of resource selection algorithms by algorithms that address the specific needs of a particular Grid environment and job submission scenario. By default, the service implements a decentralized brokering policy, striving to optimize the performance for the individual user by minimizing the response time for each job submitted. The algorithms in our implementation perform resource selection based on performance predictions, and provide support for advance reservations as well as coallocation of multiple resources for coordinated use. The performance of the system is analyzed with focus on overall service throughput (up to over 250 jobs per min) and individual job submission response time (down to under 1 s). Copyright © 2009 John Wiley & Sons, Ltd.     

ADSS光缆电腐蚀的产生及预防

电力通信的发展使ADSS光缆得到广泛应用,沿电力线路架设的ADSS光缆存在电腐蚀现象,严重时会造成光缆外护套破裂甚至断缆,为了更好地解决这一问题,应对ADSS光缆电腐蚀的产生和预防进行分析。电腐蚀现象产生的原因各不相同,通过对干带电弧、电晕放电引起的2种电腐蚀形成机理的分析,总结出在ADSS光缆生产、设计、施工、维护管理等环节中,采取的技术手段和预防措施,使ADSS光缆的电腐蚀问题得到了更好的解决。     

DGN数据到ARC/INFO数据转换

本文介绍了DGN与ARC/INFO数据的组织特点及DGN数据到ARC/INFO数据的转换方法.