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Search Results: 1 - 10 of 129810 matches for " ZHANG Shi-Gang "
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物理学报 , 1989,
Abstract: By the method of symbolic dynamics, the Farey sequences, the * products of Farey sequences and M. S. S. sequences, the binary trees and the new trajectories for varied Farey; numbers of the circle map are studied.
The dynamic process of thin films damage induced by femtosecond laser

Zhang Hong-Ying,Wu Shi-Gang,

物理学报 , 2007,
Abstract: A dynamic model of plasma explosion is put forward. The inertia factor is considered daring plasma expansion, and the dynamic simulation is carried out. The dynamic mechanism of film damage induced by plasma blast is discussed.
Influence of velocity spatiotemporal correlations on the anomalous scaling exponents of passive scalars

Zhang Xiao-Qiang,Wang Guang-Rui,Chen Shi-Gang,

中国物理 B , 2009,
Abstract: In this paper, we consider spatial-temporal correlation functions of the turbulent velocities. With numerical simulations on the Gledzer--Ohkitani--Yamada (GOY) shell model, we show that the correlation function decays exponentially. The advecting velocity field is regarded as a colored noise field, which is spatially and temporally correlative. For comparison, we are also given the scaling exponents of passive scalars obtained by the Gaussian random velocity field, the multi-dimensional normal velocity field and the She--Leveque velocity field, introduced by She, et al. We observe that extended self-similarity scaling exponents H(p)/ H(2) of passive scalar obtained by the colored noise field are more anomalous than those obtained by the other three velocity fields.
Surface energetic and bonding characteristics of tetrahexahedral platinum nanocrystals enclosed by high-index facets

Wen Yu-Hu,Zhang Yang,Zhu Zi-Zhong,Sun Shi-Gang,

中国物理 B , 2009,
Abstract: This paper uses a molecular static approach with a many-body potential to investigate the surface energetic and bonding characteristics of tetrahexahedral platinum nanocrystals enclosed by high-index facets such as 210, 310, 410, 520 and 730. It mainly focuses on the effect of crystal size and surface Miller index on these characteristics. The results show that the surface energy and dangling bond density increase with decreasing diameter of tetrahexahedral nanocrystals and generally show an order of 210 > 730 > 520 > 310 > 410. However, this order is not valid at crystal sizes below 7~nm or so. The results of corresponding surfaces are also presented for comparison.
Non-fragile H Filtering for a class of Nonlinear Sampled-data System with Long Time-Delay
Shi-Gang Wang
International Journal of Computer Science Issues , 2013,
Abstract: This paper studies the problem of non-fragile filtering for a class of nonlinear sampled-data system with long time-delay. The nonlinearity is assumed to satisfy global Lipschitz conditions, and the filter to be designed includes multiplicative gain variation, which results from filter implementations. Furthermore, to long time-delay, the direct distribution method is applied to design non-fragile filter that assures asymptotic stability and satisfy a prescribed performance index for the filtering error system. The proposed algorithm is given in terms of linear matrix inequality, whose feasibility and effectiveness has been shown by a numerical example.
A microsatellite polymorphism in IGF1 gene promoter and longevity in a Han Chinese population
Liang Xie, Yuan-ying Gong, Shi-gang Lian, Juan Yang, Shou-jun Gao, Liang-you Xu, Ya-ping Zhang
BMC Research Notes , 2010, DOI: 10.1186/1756-0500-3-55
Abstract: We recruited 493 elderly Han Chinese individuals (females ≥ 94; males ≥ 90) and 425 young individuals (controls) from Dujiangyan (Sichuan province, China). The genotype distributions and allele frequencies of the microsatellite site in the elderly and control groups were compared by chi square test.Our results suggested that there was no association between the microsatellite polymorphism and longevity in our Han Chinese population. However, there were more male persons with 18/21 genotype in elderly group than that in control group (11.11 vs. 5.45%, p = 0.011). As the difference was not significant when corrected by Bonferroni method, we speculate that the 18/21 genotype can not be functional in longevity; however, it may link with the real functional loci as there is a long haplotype block embracing the microsatellite locus.There was no association between polymorphism of the microsatellite in promoter of IGF1 gene and longevity in our study. Future association studies containing the long haplotype block are deserved and can test our speculation of the potential linkage of 18/21 genotype and functional loci.IGF1 (Insulin-like growth factor 1) plays a number of important roles in the human body. It is involved in physiological processes such as growth, development, and metabolism [1], and has been implicated as a factor in the development of common diseases [2]. Meanwhile, a conserved insulin/IGF1 signal pathway which may affect ageing and longevity is known in E.coli, yeast, drosophila, mice and humans [3-7]. Elucidating the functions of insulin/IGF1 pathway in ageing and longevity is a current hot spot in longevity research [8].Serum IGF1 levels appear to influence susceptibility to disease, and therefore longevity. For example, people with a high level of circulating IGF1 are more susceptible to cancers, while a low level of circulating IGF1 is a risk factor for cardiovascular diseases, premature atherogenesis, and diabetes [5]. Furthermore, Yang et al. suggeste

TANG Wei-qing,JIN Yong,ZHANG Shi-Gang,MA Fei,

天然气地球科学 , 2004,
Abstract: Physical information that measured by imaging-log is electric character and sound wave spread character of near well information. Information of lithology ,sediment structure and crack are gotten from imaging log measure information. Imaging log evaluation software and other evaluation soft of FORWARD geologic synthesis evaluation platform provides useful tool of geologic synthesis evaluation. This thesis gives imaging log result demonstrations of shale strip, fault, bedding, validity distinguish of crack, cycle of sediment and type examples of reservoir synthesis evaluation using imaging log information and other normal well-logging information.
An atomistic simulation of structural evolution and melting characteristics of Pt nanocrystal during continuous heating

Wen Yu-Hua,Zhang Yang,Zhu Zi-Zhong,Sun Shi-Gang,

物理学报 , 2009,
Abstract: Using molecular dynamics method with many-body potentials, we have studied the thermal stability and melting mechanism of platinum nanocrystal of truncated octahedron enclosed by {111} and {100} surfaces, and investigated its microstructure and shape by statistical radius and Lindemann index. The results show that the nanocrystal first shows shape changes at 1500 K, then transforms to a spherical one at 1700 K. The surface first shows the premelting behavior at 1500 K, and the melt completely into liquid state. The melting process starts from the surface into the interior at this temperature, resulting in the complete melting of the nanocrystal at 1730 K. The surface premelting is advantageous to shape transformation of octahedron-truncated nanocrystal.
Synthesis of Fe, N-doped Graphene/Carbon Black Composite with High Catalytic Activity for Oxygen Reduction Reaction

陈 驰,周志有,张新胜,孙世刚
, ZHOU Zhi-you, ZHANG Xin-sheng, SUN Shi-gang

- , 2016, DOI: 10.13208/j.electrochem.150849
Abstract: 摘要 以高含氮量的2-氨基咪唑为氮源,三氯化铁为铁源,高比表面积的KJ600碳黑为载体,通过水热法制得氨基咪唑聚合物前驱体,再经二次高温热处理,制得石墨烯/碳黑复合材料. 透射电镜表征显示该材料为石墨烯纳米片与碳黑颗粒的复合结构. BET表征表明这是一种多孔结构,具有很高的比表面积(882 m2?g-1),这有利于暴露更多活性位点,并促进传质. XRD证实催化剂中存在石墨烯,且石墨烯结构是在第一次热处理过程中形成的. 电化学测试表明,该催化剂在酸性和碱性介质中都具有很高的氧还原电催化活性和低H2O2产率,并且在碱性介质中对甲醇小分子的抗毒化性能明显优于商业Pt/C催化剂,展示出在实际燃料电池系统中的应用潜力.
Oxygen reduction reaction (ORR) is a bottleneck for improving the efficiency of proton-exchange membrane fuel cells as a cathode reaction due to its sluggish kinetics. The exploitation of low cost and high performance non-precious metal catalysts such as Fe/N/C based materials toward ORR has attracted extensive attentions. In this work, the Fe, N-doped graphene nanosheets/carbon black composite was prepared by hydrothermal polymerization and followed by a twice-heat-treatment procedure using 2-aminoimidazole as an N precursor, FeCl3 as an Fe precursor and KJ600 carbon black as a support. The TEM images revealed that the graphene nanosheets were separated by carbon black nanoparticles to form a robust composite architecture. This composite structure can provide high surface area and porous structure, facilitating the exposure of active sites and the mass transfer of O2. The XRD patterns proved the existence of graphene nanosheets formed during the first heat treatment. The obtained AIZ-Fe/N/C catalyst exhibited high ORR activity and low H2O2 yield in an alkaline medium. Its methanol resistance was much better than that of commercial Pt/C catalyst. Furthermore, the ORR activity in an acid medium was also impressive. These results demonstrated that the AIZ-Fe/N/C catalyst is a promising candidate to replace Pt-based catalysts as a cathode catalyst in fuel cells


中国物理 B , 1993,
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