Influence of mineral transformation on emission of particulate matters during coal combustion

Combustion of pulverized coal was studied in a drop tube furnace to understand coal mineral properties with the emission of particulate matters (PM). Experimental conditions were selected as follows: coal particle size was smaller than 63 μm; reaction temperature was 1 100°C, 1 250°C and 1 400°C respectively; oxygen content was 20% and 50% respectively. PM was collected with a 13-stagelow pressure impactor (LPI) having an aerodynamic cut-off diameter ranging from 10.0 μm to 0.03 μm for a size-segregated collection. Such properties as concentration, particle size distribution and elemental composition of PM were investigated. The experimental results indicate that the emitted PM has a bimodal distribution having two peaks around 4.0 μm and 0.1 μm. Increasing temperature leads to the formation of more PM; varied oxygen content leads to much change of emitted PM. PM was also subjected to XRF analysis to quantify the elemental composition. The results show that PM of 0.1 μm is rich in sulfates. Meanwhile, SiO₂ and Al₂O₃ are prevalent in PM of 4.0 μm, which means that the last peak around 4.0 μm is mainly aluminosilicate salts. Translated from Proceedings of the CSEE, 2005, 25(22): 104–108 [译自: 中国电机工程学报]     

水利业务协同应用的探讨

针对目前信息化发展与水利业务增长的需求不相适应,信息资源共享困难和业务协同应用欠缺等问题,提出了分布式协同应用体系的总体架构.通过业务的组件化和服务封装,依托信息资源交换与共享服务平台,提供信息、计算和决策服务,并发布应用.     

固溶时效工艺对Cu-Ni-Si合金组织和性能的影响

用扫描电镜(SEM)、硬度计、涡流电导率测量仪和万能试验机测试分别测量了在850 ～950℃固溶温度及400 ～ 500℃时效不同时间下对Cu-1.5 Ni-0.6Si合金硬度及电导率性能的影响,用金相显微镜观察不同固溶温度下合金的组织.并对合金拉伸形貌断口进行了分析.探讨了合金的强化机理.结果表明:时效前随着固溶温度的升高,材料的硬度及电导率均随之下降,但电导率下降的幅度很小.随着固溶温度的增加,其再结晶程度越来越高,到900℃时组织已是完全再结晶组织,温度继续升高,晶粒会发生长大.时效析出为Cu-1.5 Ni-0.6Si合金的主要强化手段.Cu-1.5Ni-0.6Si固溶后经不同温度时效后,时效初期硬度和电导率快速上升.随后硬度到达峰值后缓慢下降,而电导率继续上升.经过900℃×1h水淬+450℃×2h空冷处理后,合金得到良好的综合性能;其抗拉强度为780.7 MPa,伸长率为15.1％,电导率为40.2％ IACS.     

铝对复杂黄铜组织及性能的影响

用光学显微镜(OM)、硬度(HV)和万能试验机对添加不同铝含量(1.5%、2.0%、2.5%、3.0%、3.5%)的复杂黄铜(Cu-22.7Zn-Al-1.0Ni)组织与性能进行了研究.研究结果显示,铝能使合金α相区显著缩小、β相区增加,并起到细化α相、β相的作用,提高合金的抗拉强度、硬度.合金的机械性能随铝含量增加,其抗拉强度和屈服强度提高,而延伸率和冲击韧性下降,当铝含量为3.0%时,0.2 mm Y态板材硬度达到255 HV、抗拉强度达到820 MPa.     

Spectrum Co-existence of IEEE 802.11b and 802.16a Networks Using Reactive and Proactive Etiquette Policies

This paper presents an investigation of spectrum co-existence between IEEE 802.11b and 802.16a networks in the same shared frequency band using cognitive radio techniques with different levels of complexity. Simple reactive interference avoidance algorithms as well as proactive spectrum coordination policies based on etiquette protocols are proposed and compared in terms of achievable spectrum efficiency in a shared Wi-Fi/Wi-Max scenario. In reactive interference avoidance methods, radio nodes coordinate spectrum usage without exchange of explicit control information—this is done by adaptively adjusting transmit PHY parameters such as frequency, power and time occupancy based on local observations of the radio band. Because local observations provide information only about transmitters, they may not be sufficient for resolving spectrum contention in scenarios with “hidden receivers”. Proactive coordination techniques solve the hidden-receiver problem by utilizing a common spectrum coordination channel (CSCC) for exchange of transmitter and receiver parameters. Radio nodes can cooperatively select key PHY-layer variables such as frequency and power by broadcasting messages in the CSCC channel and then following specified spectrum etiquette policies. An ns2 simulation model is developed to evaluate both reactive and proactive etiquette policies in scenarios with co-existing IEEE 802.11b and 802.16a networks. The density of radio nodes in the coverage region, and their degree of spatial clustering are key parameters in the system evaluation. Detailed simulation studies were carried out for a variety of scenarios including both single and multiple 802.11b hotspots per 802.16a cell with and without spatial clustering. Our results show that simple reactive algorithms can improve system throughput when sufficient “free space” (in frequency, power or time) is available for PHY adaptation. In more congested scenarios with spatially clustered nodes and hidden receivers, the proposed CSCC etiquette can significantly improve overall system performance over reactive schemes. Research supported by NSF grant # CNS-0435370 and #0205362. Paper submitted for publication after presentation in part at IEEE DySpan 2005, Nov. 8–11, 2005, Baltimore, MD. Xiangpeng Jing received the B.S. degree in Electrical Engineering from Peking University, Beijing, P. R. China in 2000 and the M.E. degree in Electrical Engineering from City College of City University of New York, New York in 2002. He is currently a Ph. D. candidate in the WINLAB (Wireless Information Network Laboratory), Rutgers University, NJ. He has been with the MobiNet Group since 2002. His research interests include spectrum etiquette protocols, co-existence between wireless communication systems, cognitive radio technologies, and adaptive wireless ad hoc networks. Dipankar Raychaudhuri is Professor, Electrical & Computer Engineering Department and Director, WINLAB (Wireless Information Network Lab) at Rutgers University. As WINLAB’s Director, he is responsible for a cooperative industry-university research center with focus on next-generation wireless technologies. WINLAB’s current research scope includes topics such as RF/sensor devices, UWB, spectrum management, future 3G and WLAN systems, ad-hoc networks and pervasive computing. He has previously held progressively responsible corporate R&D positions in the telecom/networking area including: Chief Scientist, Iospan Wireless (2000-01), Assistant General Manager & Dept. Head-Systems Architecture, NEC USA C&C Research Laboratories (1993–99) and Head, Broadband Communications Research, Sarnoff Corp (1990–92). Dr. Raychaudhuri obtained his B.Tech (Hons) from the Indian Institute of Technology, Kharagpur in 1976 and the M.S. and Ph.D. degrees from SUNY, Stony Brook in 1978, 79. He is a Fellow of the IEEE.     

提高低硅烧结矿强度的研究及在生产上的应用

低硅烧结可明显提高成品矿的含铁品位、显著改善烧结矿的还原性、降低吨铁渣量,从而降低产品成本,提高企业的经济效益。但是由于低硅烧结时,SiO2含量较低、烧结过程产生的液相量少,而导致烧结矿强度变差、成品率下降、低温还原粉化加剧等诸多问题。针对低硅烧结矿强度变差这一突出弊端,采取了具体的应对措施,使SiO2含量为4．0％的烧结矿强度达到了入炉要求。在宣化钢铁集团公司应用中取得了良好的效果。     

生产安全调度岗位应急方案的研究与制定

1 安全生产调度岗位应急方案的研究 赵楼井田位于巨野煤田的中部,地处黄河冲积平原,地形平坦,洙赵新河与鄄郓河交汇处;地面交通纵横交错、四通八达.矿井煤层埋藏平均深度在900m左右,属深井开采,受地温热害、冲击地压、顶底板涌水危害尤为明显.为此制定细致缜密的各类事故应急预案,调度人员熟知并掌握各类预案的处置方法是做好生产安全调度岗位工作的必然要求.     

热活化黄土胶凝性能研究

借助TG、DTA、XRD等手段研究了黄土在100℃～1000℃的物相组成和热分解特征，采用凝石技术制备了以黄土为主要原料的胶凝材料，测定其力学性能并研究了赤泥掺量对其胶凝材料的力学性能影响。研究结果表明，黄土在600℃煅烧胶凝性能良好：黄土掺量达到40％时，可获得28d抗压强度超过42．5MPa的胶凝材料。而且赤泥的掺入对胶凝材料的早期强度有良好的改善作用。     

机械力化学效应对赤泥结构特性和胶凝性能的影响

依据机械力化学原理,采用高能球磨技术对煅烧赤泥进行了活化处理,并利用SEM、XRD、XPS、NMR等一系列微观测试分析工具对赤泥活化前后细度变化、矿物组成、微观结构以及化学状态等进行了研究,在此基础上阐明了机械力化学效应对赤泥结构特性和胶凝性能的影响.该原料条件下,配加50%粉磨时间为30 min赤泥的胶凝材料强度性能达到了42.5#水泥强度性能的要求,这为赤泥的高效大宗利用提供了试验依据和理论基础.