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Search Results: 1 - 10 of 79050 matches for " XU Chun-ming "
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A Synchro Partially Parallel Architecture for Quasi-Cyclic LDPC Codes

Xu En-yang Jiang Ming Zhao Chun-ming,

电子与信息学报 , 2008,
Abstract: Based on the structure of quasi-cyclic LDPC codes, a synchro partially parallel decoder is proposed in this paper. In the decoder, the check node process units and variable node process units work concurrently, where the new generated soft information is used in advance during the iteration process to accelerate the convergence speed. Furthermore, differential evolution is utilized to optimize the start positions of node process units in order to achieve better performance. Simulation results show that the proposed scheme outperforms others both in performance and complexity, and is very suitable for the implementation of high speed decoders.
Clock Representing of Finite Precision Timed Automata

LIU Chun-ming,YAN Rong-jie,XU Yu-bo,

计算机应用研究 , 2006,
Abstract: Introduces the notion of Finite Precision Timed Automata(FPTA) and focuses on the representation of clocks in a state.To reduce the state space,FPTA records the integer values of clocks together with the order of decimal fraction instead of the real number values.The performance of clock operations depends on the representation of clock-order.Present a data structure POM(Partial-Order Matrix),which is the matrix with bit elements,to represent the clock-order.The algorithms based on POM have the O(n) complexity and bit-operations are enough to all clock operations.The efficiency is improved also because there is no normalization operations in POM-based algorithms.
Simulation of the regeneration of large particle FCC naphtha aromatization catalyst

CHANG Jian,GAO Jin-sen,XU Chun-ming,
常 剑

燃料化学学报 , 2007,
Abstract: 综合考虑化学反应速率、内扩散和反应热的影响,建立单个催化剂颗粒表面烧焦过程的数学模型,模拟研究了粒径1 000 μm的球形催化剂的表面烧焦过程.研究表明,650 ℃再生,化学反应速率为控制步骤,催化剂的再生过程符合整体反应模型;800 ℃再生,内扩散影响严重,碳含量、氧分压沿径向变化剧烈.再生温度升高,催化剂颗粒的瞬时温升增大;催化剂初始碳含量越高、CO2/CO摩尔比越大,催化剂颗粒的瞬时温升越大,但再生过程所需时间增加;催化剂颗粒的径向温度分布均一.在排除外扩散影响的条件下,反应气速对再生过程影响很小.
Coke combustion kinetics of large particle catalyst in FCC naphtha aromatization

CHANG Jian,GAO Jin-sen,XU Chun-ming,
常 剑

燃料化学学报 , 2007,
Abstract: 采用微型固定床反应器和气相色谱联合装置,研究了大颗粒FCC汽油芳构化催化剂的烧碳再生动力学和再生产物中CO2与CO的摩尔比.结果表明,大颗粒FCC汽油芳构化催化剂的烧碳反应速率与碳含量和氧分压的关系符合一级反应规律;但由于受内扩散的影响,其烧碳反应速率仅为本征烧碳反应速率的60%左右.在600 ℃~720 ℃再生产物中CO2/CO摩尔比随再生温度的增加而减小,720 ℃以后,该比值显著增大;随着氧分压的增加,CO2/CO摩尔比直线增加.
燃料化学学报 , 2009,
Abstract: ?catalyticpyrolysisofchinesedaqingatmosphericresidueonacommercialfluidcatalyticcracking(fcc)catalystwasinvestigatedinaconfinedfluidizedbedreactor.theresultsshowthatthecommercialfcccatalysthasgoodcapabilityofcrackingatmosphericresiduetolightolefins.theanalysisofgassamplesshowsthatthecontentoftotallightolefinsincrackedgasisabove80%.theanalysisofliquidsamplesshowsthatthecontentofaromaticsinliquidsamplesrangesfrom60%to80%,anditincreaseswiththeenhancementofreactiontemperature.theyieldoftotallightolefinsshowsamaximumwiththeincreaseofreactiontemperature,theweightratiosofcatalyst-to-oilandsteam-to-oil,respectively.theoptimalreactiontemperature,theweightratiosofcatalyst-to-oilandsteam-to-oilareabout650℃,15and0.75,respectively.
Microbial safety control of compost material with cow dung by heat treatment
GONG Chun-ming,

环境科学学报(英文版) , 2007,
Abstract: Various kinds of pathogenic bacteria derived from the intestinal tract of animals exist in compost material like cow dung. In order to sterilize the pathogenic bacteria completely in compost material, the cow dung was put into a heat treatment machine in pilot plan, and harmless condition in short time was examined. The results indicated, pathogenic indicator bacteria such as coliform bacteria, fecal coliform, Escherichia coli and salmonella were all 106 cfu/g dw at the beginning, died rapidly when cow dung temperature rose to above 50℃, and not detected at 54-68℃ for 6-24 h heat treatment. Coliform bacteria and salmonella in heated cow dung were not detected by re-growth culture and enrichment culture examination. Moreover, it was hardly influenced on the fermentation ability of composting microbe, organic decomposition bacteria. During heat treatment, the mesophile decreased rapidly and the thermophile stabilized or increased, and the most of composting microbe were bacillus in cow dung by fluorescence microscope, it was indicated that bacillus was dominator and composting microbe in composting process.
Large volume air-gun sources and its seismic waveform characters

ZHAO Ming-Hui,QIU Xue-Lin,XIA Shao-Hong,WANG Ping,XU Hui-Long,YE Chun-Ming,KANG Ying,

地球物理学报 , 2008,
Abstract: 大容量低频组合气枪震源已成功应用于南海北部海陆联测实验及陆上水库实验,其信号传播最远距离可达255 km.为了探讨气枪信号的波形特征,从广东省地震台网数据中选择了台基相同、震级与震中距相近的珠海台的地震记录,将气枪震源、天然地震和爆破三种震源的波形特征进行了对比分析,结果表明.气枪信号特征明显,信号主频4~8 Hz,振幅±0.15 μm穝-1,波形一般具有3~5个峰值,并随时间有规律变化,易于准确识别.实验探测结果说明,这种能量强、重复性好、探测精度高、绿色环保的枪阵组合震源可广泛应用于海洋与陆地深部结构研究.
Investigation on deep crustal structure along the onshore-offshore seismic profile near Hongkong

XIA Shao-hong,QIU Xue-lin,ZHAO Ming-hui,XU Hui-Long,YE Chun-ming,CHAN Ying-wa,

地球物理学进展 , 2008,
Abstract: In order to investigate the deep crustal structure across the transition zone between land and sea of northern South China Sea, an onshore-offshore deep seismic experiment was carried out offshore Hong Kong. The permanent seismic stations of Guangdong and Hong Kong region were used to record the air-gun signals for the first time. We could identify different seismic phases and clear signals from more than 200 km distance. The deep crustal structure was studied along Profile 1. The results show that the crustal structure has strong heterogeneous characteristics. The sediments become thicker seaward. The Moho depth is about 26~29 km. The P-wave velocity is about 5.6~6.4 km/s in the upper crust, and about 6.5~6.9 km/s in the lower crust. There is a low velocity zone seaward of DanGan Islands, where the P-wave velocity is about 5.3~6.2 km/s in the upper crust and about 6.3~6.7 km/s in the lower crust. it may be the Binhai (littoral) fault zone according to former studies. The depth of Moho discontinuity change a little larger landward of DanGan Islands, it maybe relate with HaiFeng fault zone.
A cross-sectional study of HIV and syphilis infections among male students who have sex with men (MSM) in northeast China: implications for implementing HIV screening and intervention programs
Jun-Jie Xu, Kathleen Reilly, Chun-Ming Lu, Ning Ma, Min Zhang, Zhen-Xing Chu, Jun-Jie Wang, Ke Yun, Hong Shang
BMC Public Health , 2011, DOI: 10.1186/1471-2458-11-287
Abstract: A cross-sectional study of MSM high school and college students in Liaoning Province was conducted. Data were collected through face-to-face interviews and blood specimens were obtained and tested for HIV and syphilis.There were 436 eligible participants. HIV and syphilis prevalence was 3.0% and 5.0%, respectively. In multivariate analysis, sexual orientation known by family members (OR: 7.3; 95% CI: 1.5-34.6), HIV/AIDS information obtained from clinical doctors (OR: 6.7; 95% CI: 1.7-25.9), HIV/AIDS information obtained through free educational services and materials such as voluntary counseling and testing (VCT) and condom distribution services (OR: 0.2; 95% CI: 0.4-1.0), inconsistent condom use (OR: 5.7; 95%: 1.3-25.3), sexual partner experienced anal bleeding after insertive anal intercourse (OR: 6.8; 95% CI: 1.6-28.4), and history of illegal drug use (OR: 18.9; 95% CI: 2.2-165.3) were found to be significantly associated with HIV infection.Greater effort should be made towards stemming the HIV and syphilis epidemics among Chinese student MSM. Immediate screening and comprehensive interventions towards student MSM should be implemented in order to curb the spread of HIV. Family and school-based interventions should be considered to target this educated, yet vulnerable, population.Acquired Immune Deficiency Syndrome (AIDS) is currently one of the leading causes of death among 15 to 24-year adolescent and young adults [1]. Reducing adolescent sexual risk behaviour has become an international public health priority [1]. In China, MSM accounted for 12.2% of new HIV cases in 2007 [2], while in 2009 the proportion increased to 32.5% of all new HIV cases [3]. Several large cities in China have found a steady increase in HIV prevalence among MSM [4-7]. It is important for China to curb the spread of the HIV epidemic among this vulnerable population. Several recent studies of Chinese MSM found that between 27.9%-72.3% of MSM study participants were college educated [8,9],
Joint Bit and Power Allocation Algorithms for MIMO-OFDM Systems

Xu Wei,Zhao Chun-ming,Gong Xiao-qun,Zhang Li,

电子与信息学报 , 2007,
Abstract: In this paper,adaptive modulation and power allocation techniques are investigated for MIMO-OFDM systems.A computationally efficient optimal joint bit and power allocation algorithm is proposed.For implementation simplicity,a simplified sub-optimal algorithm exploiting equal power allocation is presented. Simulation results show that the proposed joint allocation algorithm obtains optimal performance with low computational complexity.Moreover,compared with the optimal algorithm using equal power allocation,the presented sub-optimal algorithm reduces the complexity significantly with slight performance degradation.
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