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Search Results: 1 - 10 of 112780 matches for " Jia-yi Liu "
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Roasting and leaching behaviors of vanadium and chromium in calcification roasting–acid leaching of high-chromium vanadium slag
Jing Wen,Tao Jiang,Mi Zhou,Hui-yang Gao,Jia-yi Liu,Xiang-xin Xue
- , 2018, DOI: https://doi.org/10.1007/s12613-018-1598-3
Abstract: Calcification roasting–acid leaching of high-chromium vanadium slag (HCVS) was conducted to elucidate the roasting and leaching behaviors of vanadium and chromium. The effects of the purity of CaO, molar ratio between CaO and V2O5 (n(CaO)/n(V2O5)), roasting temperature, holding time, and the heating rate used in the oxidation–calcification processes were investigated. The roasting process and mechanism were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetry–differential scanning calorimetry (TG–DSC). The results show that most of vanadium reacted with CaO to generate calcium vanadates and transferred into the leaching liquid, whereas almost all of the chromium remained in the leaching residue in the form of (Fe0.6Cr0.4)2O3. Variation trends of the vanadium and chromium leaching ratios were always opposite because of the competitive reactions of oxidation and calcification between vanadium and chromium with CaO. Moreover, CaO was more likely to combine with vanadium, as further confirmed by thermodynamic analysis. When the HCVS with CaO added in an n(CaO)/n(V2O5) ratio of 0.5 was roasted in an air atmosphere at a heating rate of 10°C/min from room temperature to 950°C and maintained at this temperature for 60 min, the leaching ratios of vanadium and chromium reached 91.14% and 0.49%, respectively; thus, efficient extraction of vanadium from HCVS was achieved and the leaching residue could be used as a new raw material for the extraction of chromium. Furthermore, the oxidation and calcification reactions of the spinel phases occurred at 592 and 630°C for n(CaO)/n(V2O5) ratios of 0.5 and 5, respectively.
The Field Experiment of Atmospheric Boundary Layer over Heterogeneous Surface in Baiyangdian Area-Introduction and Preliminary Data Analysis
白洋淀地区非均匀大气边界层的综合观测研究——实验介绍及近地层微气象特征分析

HU Fei,HONG Zhong-Xiang,CHEN Jia-Yi,LIU Xi-Ming,
胡非
,洪钟祥,陈家宜,刘熙明

大气科学 , 2006,
Abstract: A comprehensive field experiment of atmospheric boundary layer over heterogeneous surface is introduced.The experiments were held in Baiyangdian area of North China during 1622 November 2004 and 827 September 2005.Some micrometerological characteristics from preliminary data analysis shows that(1) the diurnal variation of air temperature over the land is more obvious than that over the water area and the wind speed over the land is less than that over the water area.In September,the air temperature over the land is higher than that over the water area in the daytime,but lower at nighttime.In November,the air temperature over the land is almost the same as that over the water area in the daytime,but is lower obviously at nighttime.Either in November or in September,the vertical speed over the water area is always negative,but over the land,there is sometimes a positive vertical speed at noon;(2) in September,the incident shortwave radiations over the land and the water area are almost the same,but the reflected shortwave radiation over the water area is much more than that over the land.The incident long wave radiation over the land is much more than that over the water area,but the reflected long wave radiation over the land is less than that over the water area.The net radiations over the land and water area are almost the same in the daytime,but there is a difference at night;(3) the albedo over the land is smaller than that over the water area;(4) in September,the sensible heat fluxes over two sites are about 150-200 W/m~(2),and the latent heat fluxes are near 300 W/m~(2) in shiny days.In November,the sensible heat flux is larger than the latent heat flux over the land,and the sensible heat flux is smaller than the latent heat flux over the water area.There are always minus latent heat fluxes over the water area;(5) in September,the water body temperature is much higher and changes more slightly than the water surface temperature.
Pro-backup repairing mechanism based on AODV
基于AODV的改进型备用路由修复协议

JIANG Wen-tao,KUANG Yu-Jun,LIU Jia-yi,LONG Ke-ping,
蒋文韬
,邝育军,刘佳轶,

重庆邮电大学学报(自然科学版) , 2008,
Abstract: 移动Ad Hoc网络是一种路由多跳且无固定设备的无线网络,每个移动节点都拥有路由发现和维护功能。由于结点的任意移动导致网络拓扑频繁改变并影响其传输质量,大部分现有的路由协议都不能及时维护路由。提出了一种基于AODV,通过监听RREP的PR-AODV协议。当主路由不可用时,PR-AODV协议立即建立更稳定的备用路由。经过仿真,在高移动性的网络环境中,PR-AODV与AODV相比,在报文投递率、控制包开销方面的性能相似,但PR-AODV有更低的时延。
白洋淀地区非均匀大气边界层的综合观测研究——实验介绍及近地层微气象特征分析
胡非 HU Fei,洪钟祥 HONG Zhong-Xiang,陈家宜 CHEN Jia-Yi,刘熙明 LIU Xi-Ming
大气科学 , 2006, DOI: 10.3878/j.issn.1006-9895.2006.05.17
Abstract: 介绍了国家自然科学基金重点项目"地表通量参数化与大气边界层过程的基础研究"在河北省白洋淀地区进行的两次综合观测实验(时间分别是2004年11月16~22日和2005年9月8~27日),这两次实验获得了大量宝贵的资料,全面深入的资料分析正在进行中.此文主要限于白洋淀地区水陆不均匀地表近地面层微气象特征的分析.结果表明:陆地上近地面层的气温日变化比水域上的大,而风速比水域上的小,其中9月份陆地上白天的气温比水域上的高,夜间比水域上的低,11月份两地白天气温接近,但夜间陆地上的气温明显偏低;无论是9月还是11月,水域上近地面层都是以下沉气流为主,而陆地则在中午前后存在弱的上升运动;9月份,两地的近地面层短波射入辐射比较接近,但水域上的短波射出辐射比陆地上的大;长波射入辐射则是陆地比水域的大,而长波射出辐射则是水域的比陆地的大;两地的净辐射白天接近,夜间水域地区负的净辐射值明显比陆地的大;9月份,水陆两地的感热通量相差不大,为150~200W/m2,而潜热通量比感热通量大,天气晴朗时可达到300W/m2;11月份,陆地的感热通量比潜热通量大,为100~120W/m2,而水域地区的感热通量则与潜热通量相当;两地的潜热通量相差不大,一般不超过50W/m2.无论是9月还是11月,水域地区夜间都存在水汽向下输送的逆湿现象,而陆地只在9月份存在逆湿现象.2005年9月份的水温观测结果表明,白洋淀水体平均温度比水表平均温度明显偏高,而且日变化幅度很小,水表平均温度则日变化较大.
The Underestimation of the Turbulent Fluxes in Eddy Correlation Techniques
涡旋相关法测定湍流通量偏低的研究

CHEN Jia-Yi,FAN Shao-Hu,ZHAO Chuan-Feng,XIAO Xue,CAI Xu-Hui,LIU Hui-Zhi,
陈家宜
,范邵华,赵传峰,肖雪,蔡旭辉,刘辉志

大气科学 , 2006,
Abstract: A series of large eddy simulations is performed for convective boundary layer(CBL) with homogeneously heated surface.The research aims at investigating the lack of energy budget closure on field energy flux measurements reported in recent years.Time series of simulated turbulent wind,temperature and humidity show the frequent occurrence of low-frequency eddies,which appear as the cluster-like thermals in the CBL.Following data processing procedures adopted in eddy correlation techniques,the covariances with linear tendency removal or mean removal only are calculated based upon the data produced from the large eddy simulation(LES).The results show that the failure to capture low-frequency eddies due to finite sampling length is responsible for the great loss of fluxes evaluated by eddy correlation techniques in low wind CBL.The underestimation of energy fluxes increases with increasing of the height and decreases with increasing of the wind speed.The results may enhance the understanding of the inadequate sampling problem in eddy correlation techniques.
Solid Lubricating Film/oil or Grease Complex System I:Tribological Properties of MoS_2 Film at Dry Sliding and Coated with Trifluorinated-butyl with Methyl Terminated Silicon Oil or the Related Grease Formulated with Powder of PTFE
固体-油脂复合润滑Ⅰ:二硫化钼膜在干摩擦及空间用油脂润滑下的摩擦学性能

HAO Jun-ying,WENG Li-jun,SUN Jia-yi,LIU Wei-min,
郝俊英
,翁立军,孙嘉奕,刘维民

摩擦学学报 , 2010,
Abstract: The use of space satellites for communication and navigation is ever increasing in both military and commercial applications. High costs for both constructing and launching satellites are driving the need to extend the useful lifetime of these satellites. Improving lubrication of the mechanical systems is one of the key issues for prolonged service lifetime of satellite or spacecraft.MoS2-based film was prepared by rf-sputtering. Lubricants, i.e. trifluorinated-butyl with methyl terminated silicon oil (code as 115# oil) and the related grease formulated by PTFE powders (code as KK-5 grease) were synthesized at laboratory. Friction and wear properties of the MoS2 film, MoS2 film coated with 115# oil or KK-5 were investigated on a UMT-2MT tribo-meter. The effects of load and speed on friction and wear were also investigated. The worn surfaces of the MoS2 and its counterpart AISI 52100 steel balls were observed by scanning electron microscopy (SEM). It was found that the friction coefficient and wear lifetime of MoS2 dry-film were about 0.11 and 1.0×105 revolution, respectively. The friction and wear properties of solid lubricating film/oil or grease complex lubrication system were much better than that of MoS2 dry-film. The friction coefficient and wear lifetime of the MoS2 film lubricated with KK-5 grease were about 0.09 and 2.1×105 revolution, respectively. The complex lubrication system, MoS2 +115# oil, exhibited excellent friction and wear properties. Its friction coefficient was about 0.07 and its wear lifetime exceeded 8.0×105 revolution.
Opportunities and Challenges to Space Tribology
空间摩擦学的机遇和挑战

WENG Li-jun,LIU Wei-min,SUN Jia-yi,Xue Qun-jiof Chemical Physics,Chinese Academy of Sciences,Lanzhou,China,
翁立军
,刘维民,孙嘉奕,薛群基

摩擦学学报 , 2005,
Abstract: A riview was given on the requirements for lubricating materials and technologies posed by the space programs and on the state-of-the-art of space tribology in China. It was pointed out that space tribology should be considered as the science and technology dealing with the friction, wear, and lubrication of the interacting surfaces in relative motion of space-related components under space conditions. It was noted that the studies in the space tribology would help to establish the scientific ground and technological know-how for the development of lubricating materials and technologies for space application. Moreover, the challenges to the space tribology in China were listed, and it was suggested to enhance and deepen the related studies on novel solid and liquid lubricating materials and technologies for aerospace application so as to guarentee the smooth development of the national space programs.
Crystal Structure and Friction and Wear Properties of Cu Films Deposited at Low Temperatures by Ion Plating
低温沉积Cu膜的晶体结构及摩擦磨损性能的初步研究

GAO Xiao-ming,SUN Jia-yi,HU Ming,WENG Li-jun,LIU Wei-min,
高晓明
,孙嘉奕,胡明,翁立军,刘维民

摩擦学学报 , 2007,
Abstract: 采用离子镀技术于45#钢基体表面在低温(164~115 K)和常温(291 K)条件下沉积Cu膜,通过X射线衍射仪、扫描电子显微镜研究Cu膜的晶体结构及其表面形貌,采用划痕试验法测量Cu膜的临界载荷(Lc),在真空球-盘摩擦磨损试验机上考察其摩擦磨损性能并探讨其磨损机理.结果表明:基体温度对Cu膜的择优取向影响明显,在常温(291 K)下沉积的Cu膜为(200)择优取向,基体温度降至164 K以下所沉积的Cu膜呈现出明显的(111)择优取向;低温沉积Cu膜的表面较为光滑,其Lc值明显高于常温沉积的Cu膜;低温沉积Cu膜的磨损率明显低于常温沉积Cu膜,表现出良好的耐磨性,这主要是由于低温沉积Cu膜具有(111)择优取向和良好的膜-基结合力的缘故.
Preparation and Primary Investigation of the Tribological Properties of Ion-Plated Cr-Ni-N Composite Films on Stainless Steel
Cr—Ni—N复合薄膜的制备及其摩擦磨损性能初探

HU Ming,SUN Jia-yi,WENG Li-jun,LIU Wei-minof Chemical Physics,Chinese Academy of Sciences,Lanzhou,China,
胡明
,孙嘉奕,翁立军,刘维民

摩擦学学报 , 2005,
Abstract: Cr-Ni-N composite films were deposited on 9Cr18 steel using multi-arc ion plating technology. The effect of N_2 flux on the structure of the films was investigated. The phase compositions of the composite films were examined by means of X-ray diffraction. The tribological properties of the Cr-Ni-N composite films sliding against 9Cr18 steel in vacuum were investigated on a ball-on-disc test rig, using ion-plated Ni, Cr, and CrN films as the comparison. And the cross-section and worn surface morphologies of the composite films were observed using a scanning electron microscope. It was found that the composite films had much higher microhardness and much better wear resistance than the reference films deposited under the same conditions. The compositions and microstructures of the composite films were highly dependent on the N_2 flux. Namely, mono ceramic phase CrN was generated in the composite film at a N_2 flux of 7 sccm, while binary ceramic phases Ni_3N and Cr_2N were produced in the composite films at N_2 flux of 15 sccm and 30 sccm. This accounted for the higher hardness and better wear resistance of the composite films prepared at larger N_2 flux than the one prepared at a small N_2 flux of 7 sccm. Moreover, the better mechanical and tribological properties of the Cr-Ni-N composite films than the ion-plated Ni, Cr, and CrN films were closely related to the nanocrystalline structures.
涡旋相关法测定湍流通量偏低的研究
陈家宜 CHEN Jia-Yi,范邵华 FAN Shao-Hua,赵传峰 ZHAO Chuan-Feng,肖雪 XIAO Xue,蔡旭辉 CAI Xu-Hui,刘辉志 LIU Hui-Zhi
大气科学 , 2006, DOI: 10.3878/j.issn.1006-9895.2006.03.06
Abstract: 针对野外实验所发现的不同观测法测定地表能通量不平衡问题,进行了均匀加热大气边界层的大涡模拟实验.用模拟的湍流风、温度和湿度涨落的时间序列证实,对流边界层低频涡普遍存在,并经常以一簇一簇热泡的形式出现.风速较小时,有限时长的取样不足以捕捉低频涡的贡献,可造成涡旋相关法测量的统计量异常偏低.仿照涡旋相关法的步骤进行数据处理发现,经去除平均或趋势计算的温度和湿度通量偏低程度在边界层下部随观测高度的增高而显著,其中尤以湿度通量为甚.其结果在一定程度上可以解释低风速条件下地表能通量测量的不闭合问题,但是尚不能完全解释诸如青藏高原实验出现的严重不闭合.文中对此作了探讨性的讨论.
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