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June 30,2009
Volume 2,Issue 12
Pages 1215-1314
Subject Area:Communication Network Technology,Communications Technology,Fire Engineering,Industrial Poisoning Control Engineering,Ventilation Engineering Conditioning,Energy Storage Technology

Title: Layered charging policy research in content-based charging under 3G networks

Authors: YIN Changqing， LI Xiaofeng
PP: 1308～1314
Abstract: This paper studies the sorts of charging policy and configuration process with the layered charging architecture of 3G content-based charging. It also brings up the layered charging policy mechanism and explains the specific ways to configure different policies in details. In terms of the configuration of charging policies, this mechanism can configure the charging policy for a specific service statically and united, and configure the personalized charging policies dynamically for flexible charging purpose. In view of flexibility and precise, it can satisfy the layered uniform charging and fulfill the 3G content-based charging requirement of flexible and precise charging.
Keywords: communication technology; content-based charging; charging policy; policy and charging control

Title: Research on K-coverage CGS algorithms with different sensing radius

Authors: LIU Tianshu, HU Zhen, SONG Zhengxun, HAN Lei
PP: 1300～1307
Abstract: This paper presents the coverage and connectivity problems of wireless sensor networks (WSN), explains the coverage problems of WSNs in detail, outlines the issues of WSN coverage requiring urgent solution, and gives a controlled greedy sleep (CGS) algorithm based on K -coverage. By adopting WSN coverage mode with different sensing radius and utilizing the mended K -NC CGS algorithm, it gains the network coverage rate which is more in line with the practical application and lifetime.
Keywords: communication technology; K-coverage; CGS algorithm; K-NC CGS algorithm; coverage rate; lifetime

Title: A novel service-based dynamic weight setting network selection algorithm

Authors: ZHU Lifeng， CUI Hongyan， YAN Qiangjun
PP: 1295～1299
Abstract: In the future mobile systems, various wireless access technologies will exist simultaneously and constitute a complicated heterogeneous network environment. Considering the services, a novel network selection algorithm based on dynamic weight setting is proposed in order to solve the existing problems that there is not a tradeoff among users’ preference and network conditions, and only considers single handoff parameter in the present handoff decision schemes. A possibility-based method is used for handoff cost function. Network selection adopts principle in order for the efficient wireless source utilization. Simulation results show that the proposed algorithm is favorable to improve the whole QoS performance of services, and enhance the performance-price ratio of the selected networks.
Keywords: communication technology; dynamic weight; analytic hierarchy process; coefficient of variation; uncertainly multi-attribute decision making; always suitable connected

Title: The corrosion behavior of new types zirconium alloys in 500℃/10.3 MPa water steam

Authors: XIONG Ji, WANG Jun，LONG Chongsheng，MIAO Zhi，FAN Hongyuan，HUANG Zhaohua，YING Shihao
PP: 1289～1294
Abstract: The corrosion behaviors of Zr- x Nb- y Cu alloys have been investigated in the steam-gas of 500℃ and 10.3 MPa by autoclave tests. The results showed that the corrosion behaviors of them were distinct. The uniform corrosions occurred on the Zr- x Nb- y Cu alloys. The Zr-1.0Nb-0.05Cu specimens have the best corrosion resistance, rather than N18 alloy. The second phase particles of uniform distribution and higher density are beneficial to improving the corrosion resistance in steam-gas. However, the composition of zirconium alloys is a more important factor with a potential possibility for improving the corrosion resistance in 500℃/10.3 MPa environment by adjusting the composition of zirconium alloys.
Keywords: nuclear materials and process technology; Zr-Nb-Cu alloy; hot water steam; autoclave corrion; microstructure

Title: Analysis of flow characteristics of slug bubble in stagnant and flowing liquid in vertical tube

Authors: WANG Hongyan, YAN Changqi, CAO Xiaxin, WANG Wenbo
PP: 1284～1288
Abstract: The relation between the slug flow and the general trend of pressure signal cure in stagnant liquid was explained, and the impact of the entrance pressure on the slug bubble rise velocity was analyzed. Besides, the effect of different water and gas flow rates on slug bubble rise velocity under the flowing condition was analyzed. It was found that the different entrance pressures did not affect the slug bubble speed under the stagnant condition, and the increase of slug bubble rise velocity mainly depended on the increase of the gas-liquid two-phase mixture velocity in the turbulent state. Moreover, the slug bubble rise velocity expression was given in the turbulent flow state, which fit the empirical formula well by contrasting.
Keywords: nuclear power engineering; vertical tube; slug flow; stagnant liquid; flowing liquid; flow characteristics

Title: Nonlinear transport of intense direct-current beam

Authors: LV Jianqin, ZHAO Xiaosong
PP: 1280～1283
Abstract: Nonlinear transport of intense direct-current (dc) beams in electrostatic quadrupoles was analyzed by the Lie algebraic methods, and the second-order approximate particle trajectories were obtained. Based on theoretical analysis results, a computer program was designed. In order to make the calculation results self-consistent, each element in the program was divided into pieces, and piecewise iteration was applied. As a practical example, a low energy beam transport system consisting of drift space-electrostatic quadrupole doublet-drift space was calculated. The results were tested by PIC calculation, and they agreed to each other.
Keywords: physics of particle accelerator; intense direct-current beam; nonlinear trajectory; Lie algebraic method

Title: Safe evacuation model and calculation method of building

Authors: LI Xicai, HAO Lili, FAN Shuai, SHI Meijing, XU Xiaoyi
PP: 1275～1279
Abstract: In this paper, a model is established and calculation is performed according to width of corridor of evacuation exit, widths of entrances of staircase and its antechamber, stair flight width, stair antechamber area and so on to ensure that people can be evacuated to safe place within a certain time in fire. The safe evacuation calculation is based on the assumption that fire occurs on a floor, predicts that all the people on the floor are all evacuated to the lower floor, and checks the evacuation safety. The check step usually takes each floor as checking unit, but can also check safe evacuation of only one sub-area or simultaneous evacuation of several floors or the whole building.
Keywords: safety science; building; safe evacuation; evacuation model; calculation method

Title: Experimental study on shock wave transmission law of gas explosion at turning points of pipeline

Authors: JING Guoxun, SHI Guo, JIA Zhiwei
PP: 1270～1274
Abstract: In order to study the transmission law of the air shock wave at turning points of tunnel after the gas explosion, the paper processed the experiment at different turning points with turning angles of 30 45 60 and 90 The system changed the filling length of the gas taking part in the reaction to change the initial overpressure of the shock wave, and obtained the overpressure change curve of the explosion shock wave at the different tunnel turning point angles. The results show that, with the increase of the initial overpressure, the overpressure attenuation coefficient of the shock wave increases gradually; and with the aggrandizement of the turning point angle, the overpressure attenuation coefficient of the shock wave also slightly increases. The experimental results have enriched the transmission law of the gas explosion shock wave in complex tunnel, and have positive significance to prevent and control destruction and injury function of the shock wave.
Keywords: safety engineering; gas explosion; shock wave; overpressure; transmission law

Title: Experimental study of integration of fire detection systems in a large high volume space

Authors: FANG Jun, TU Ran, MEI Zhibin, LIU Kai, ZHANG Yongming
PP: 1262～1269
Abstract: In a large volume space, several fire detection systems are arranged in multi layers with different heights to investigate the responses to standard fires under different fire situations and disturbance conditions. The experiments show that beam type and light section image smoke detectors at the different heights with the same spacing respond to the smoldering fire smoke from the lowest position to the highest position in sequence, while for flaming fire, the sequence is opposite, and light section image smoke detector responds with low missing alarms for its overlapping beams; open window ventilation has a significant effect on the heights and widths of the fire smoke plumes, which determines the location height and spacing of beam smoke detectors; aspiration smoke detectors respond to fire smoke slowly but without missing alarms; wall fire rises more quickly than center fire reducing the detection time of beam type and aspiration smoke detectors; image flame detector is more sensitive to the distance between detector and fire source than radiation energy detector. Smoke plume and detector modeling theories are introduced to interpret the experimental results.
Keywords: safety engineering; fire safety; large and high space; fire detection; smoke plume; integration of systems

Title: Development and application of experimental teaching model of automatic mine ventilation control

Authors: YANG Guang, GAO Jingfeng, JIANG Dayong, MA Heng
PP: 1258～1261
Abstract: Mine ventilation experiment usually requires a large area of experimental tunnels and cooperation of many people, which is time-consuming and laborious. The teaching demonstration often can not achieve expected effect because of many problems such as instrument precision. According to similarity principle, PVC pipes were used to construct small mine model. Pressure difference sensors, wind speed sensors and air-door actuators were used to perform simulation and experiment of the mine ventilation. The host computer software was compiled with Visual Basic program. The CAN-BUS acquired simulation signals of pressure difference and wind speed and outputted air-door angle control simulation signals to perform practical monitoring and controlling. The system has advantages of low cost, small volume, simple and intuitionistic operation, and many functions.
Keywords: ventilation and air-conditioning engineering; mine ventilation; automatic control; experimental teaching; system development

Title: Hydrogen energy and new nanomaterials for hydrogen storage

Authors: WANG Xiaoen
PP: 1252～1257
Abstract: This paper introduces the development of materials for hydrogen storage under new energy stratagem. Both the single-walled carbon nanotubes and the alkali metal doped fullerene (C60) have excellent application prospect. The recent results show that the maximal hydrogenation degree of nanotube depends on the nanotube diameter and the single-walled carbon nanotube-hydrogen composite with diameter value around 2.0 nm have almost 100% hydrogenation degree and a hydrogen storage capacity higher than 7 wt% due to formation of reversible carbon-hydrogen bonds, while the hydrogen storage capacity of the sodium atom doped fullerene is up to 9.5 wt% and is stable at room temperature.
Keywords: energy and energy saving; materials for hydrogen storage; single-walled carbon nanotubes; sodium atom doped fullerene; hydrogen storage capacity; chemisorption

Title: Quantitative calculation of formation water discharge in gas drilling

Authors: YAN Tie, LIU Shunli, BI Xueliang
PP: 1247～1251
Abstract: In the process of gas under-balance drilling, the problem of formation water discharge is one of the bottlenecks of this technique application. It is very important that the amount of formation water discharge is accurately calculated and the positions of formation water discharge are predicted for the implementation of under-balanced drilling. At present most of the computational methods about formation water discharge are qualitative, and some of them are so simple that they could cause probable errors. In this paper, the quantitative models of formation water discharge are established on the basis of the predecessor’s research. In these models, not only the reservoir characteristics are considered, but also the reservoir opening process is combined with the reservoir Darcy flow and non-Darcy flow. Based on this, the discrimination mode of the formation water seepage way is developed by means of parametric analysis and the filtrational characteristic of resident fluid. The critical discriminating curve is obtained for Darcy flow and non-Darcy flow and it provides the theoretical basis for the further research of solving the problem of formation water discharge. The outstanding feature of this model is to calculate the water yield with the different models according to the different filtrational characteristics. It also overcomes the defect of calculating the water yield in the single model before.
Keywords: drilling engineering; gas drilling; under-balanced drilling; formation water discharge; Darcy flow; non-Darcy flow

Title: ZnTe∶Cu polycrystalline thin films as back contact layers

Authors: SONG Huijin, ZHENG Jiagui, FENG Lianghuan, XIA Gengpei, WANG Wenwu,HE Jianxiong, LI Yuanjie, YAN Qiang
PP: 1242～1246
Abstract: ZnTe∶Cu polycrystalline thin films prepared by vacuum co-evaporation technique were characterized by X-ray Diffraction (XRD), Atomic Force Microscope (AFM) and X-ray Photoelectron Spectroscope (XPS). The paper studied the impact of copper-doped concentration and annealing temperatures upon structure and surface morphology of ZnTe∶Cu thin films and analyzed existing state of copper atoms. It is shown that as-deposited ZnTe films have cubic structure with highly preferential orientation of (111) while the annealed ZnTe films have hexagonal structure. The XPS analysis shows that, on the surface of annealed ZnTe∶Cu films, Te exists in forms of oxide and CuxTe. CdTe solar cell conversion efficiency and its characteristic have been improved when the ZnTe/ZnTe∶Cu back contact layers are introduced into CdTe solar cells.
Keywords: primary energy; ZnTe∶Cu polycrystalline film; composite film structure; solar cell

Title: Experimental study on hydrate formation process in silica gel

Authors: SUN Zhigao, JIANG Chengming, XIE Nuolin
PP: 1239～1241
Abstract: Natural gas hydrate in nature mainly exists in sea floor. Natural gas hydrate always forms in porous sediment. A rig for the study of hydrate formation in porous media was set up. Methane hydrate formation process in porous silica gel was studied, using silica gel with average pore diameter 8.3 nm as carrier. The experimental results showed that the formation pressure (equilibrium pressure) of methane hydrate increased, but hydrate nucleation happened easily and induction time decreased greatly. Methane hydrate formation in porous silica gel included two stages where the formation speeds of methane hydrate were obviously different.
Keywords: primary energy; hydrate; methane; crystal growth; porous silica gel

Title: Preparation and characterization of Ni-Co and Ni-Fe alloy based anodes for low-temperature solid oxide fuel cells

Authors: LANG Ying, XIE Zhen, PENG Ranran, XIA Changrong
PP: 1234～1238
Abstract: Ni0.5Co0.5 and Ni0.5Fe0.5 alloys were investigated as anodes for low-temperature solid oxide fuel cells (LT-SOFCs). The alloys were formed by in situ reduction of Ni0.5Fe0.5Oy and Ni0.5Co0.5Oy composites, which were synthesized using a glycine-nitrate technique. Ni0.5Co0.5-SDC (Ce0.8Sm0.2O1.9) and Ni0.5Fe0.5-SDC supported single cells were prepared using a co-pressing and co-firing process. Interfacial polarization resistances and I-U curves of these cells were measured at 600℃. With Ni0.5Co0.5-SDC as anode, the maximum power density of the cell was about 616 mWcm-2 when humidified (3% H2O) hydrogen was used as fuel and stationary air as oxidant, while Ni0.5Fe0.5-SDC as anode, the maximum power density was only 380 mWcm-2. The interfacial resistances of the two cells were 0.121 and 0.238 Ω/cm2, respectively, which accounted for big difference in power density. X-ray diffraction (XRD) was used to identify the phase of Ni0.5Fe0.5Oy and Ni0.5Co0.5Oy composites sintered at 1 200℃. It was shown that the Ni0.5Fe0.5Oy consisted of NiO and NiFe2O4 composites, while Ni0.5Co0.5Oy only formed CoNiO2. The difference in the consistent of the two composites might account for the distinctness in the microstructure and then the electrochemical performance of the corresponding alloys. Alloy based cermets might be promising anodes for SOFCs.
Keywords: inorganic nonmetallic materials; low-temperature solid oxide fuel cells (LT-SOFCs); co-pressing and co-firing; Ni-Co; Ni-Fe; alloy based anodes

Title: Application of microwave field in acid leaching process of metallurgical grade silicon

Authors: YU Zhanliang, XIE Keqiang, MA Wenhui, ZHOU Yang, YANG Bin, DAI Yongnian
PP: 1229～1233
Abstract: To decrease metallic impurity residue in metallurgical grade silicon, the influences of different reaction conditions (microwave field, planetary mill and aqueous thermostat) on removal effect of the metallic impurities in the metallurgical grade silicon. The experimental results showed that the removal efficiencies of iron, aluminum, calcium and titanium in the metallurgical grade silicon under microwave field were 83%, 73%, 93% and 54%, respectively; the removal efficiencies of iron, aluminum, calcium and titanium in the metallurgical grade silicon under planetary mill were 78%, 69%, 83% and 46%, respectively; and the removal efficiencies of iron, aluminum, calcium and titanium in the metallurgical grade silicon under aqueous thermostat were 72%, 54%, 67% and 38%, respectively. The effect of the microwave field was evidently better than those of the planetary mill and aqueous thermostat, and the reaction time under the microwave field was shorter. The principles of hydrometallurgical purification of the metallurgical grade silicon under microwave field and planetary mill were discussed respectively.
Keywords: physical chemistry of metallurgy; extractive metallurgy; metallurgical grade silicon; microwave field; planetary mill; aqueous thermostat

Title: Prospect and retrospect of fused salt electrolysis process for producing refractory metals

Authors: LU Xionggang, ZOU Xingli, LIU Jianmin, CHEN Chaoyi, CHENG Hongwei
PP: 1221～1228
Abstract: This paper reviews the conventional fused salt electrolysis process for production of refractory metals and analyzes its shortages. New fused salt electrolysis processes such as FFC process and SOM process are introduced, especially, introducing a modified SOM process proposed by Shanghai University which succeeds in extraction of refractory metals such as titanium, tantalum and chromium directly from their respective oxide, and as well introducing the prospect of new fused salt electrolysis process for extracting titanium or its alloy from Ti-bearing blast furnace slag and ilmenite. The new electrolysis processes open up a new field for producing refractory metals with low cost and have a good future. It proposes a new idea for comprehensively utilizing the complex mineral resources.
Keywords: nonferrous metallurgy; refractory metals; review; fused salt; FFC process; SOM process

Title: Current research progress of flow stimulation in continuous casting mold

Authors: LU Xiangyang, LIU Guoqi, MA Tianfei, YANG Wengang
PP: 1215～1220
Abstract: To optimize the flow pattern in the mold and improve the quality of the steel, continuous casting parameters such as immersion depth and casting speed are often studied by the simulation methods. Physical stimulation and numerical stimulation are both effective means to study the flow patterns in the mold for the continuous casting. The principle, experimental methods, contents and flow evaluation methods for physical stimulation and numerical stimulation are reviewed in this paper and the suggestions are also raised.
Keywords: ferrous metallurgy; physical stimulation; review; numerical stimulation; flow field; mold

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