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A nonlinear Schrodinger equation for gravity waves slowly modulated by linear shear flow

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Chinese Physics B 2019年第12期28卷 215-222页

作者： shaofeng li Juan Chen Anzhou Cao Jinbao Song Ocean College Zhejiang UniversityZhoushan 316000China

Assume that a fluid is inviscid, incompressible, and irrotational. A nonlinear Schr?dinger equation(NLSE) describing the evolution of gravity waves in finite water depth is derived using the multiple-scale analysis method. The gravity waves are influenced by a linear shear flow, which is composed of a uniform flow and a shear flow with constant vorticity. The modulational instability(MI) of the NLSE is analyzed, and the region of the MI for gravity waves(the necessary condition for existence of freak waves) is identified. In this work, the uniform background flows along or against wave propagation are referred to as down-flow and up-flow, respectively. Uniform up-flow enhances the MI, whereas uniform down-flow reduces it. Positive vorticity enhances the MI, while negative vorticity reduces it. Hence, the influence of positive(negative)vorticity on MI can be balanced out by that of uniform down(up) flow. Furthermore, the Peregrine breather solution of the NLSE is applied to freak waves. Uniform up-flow increases the steepness of the free surface elevation, while uniform down-flow decreases it. Positive vorticity increases the steepness of the free surface elevation, whereas negative vorticity decreases it.

关键词： nonlinear Schrodinger equation gravity waves linear shear flow modulational instability

Inactivation of Cryptosporidium by ozone and cell ultrastructures

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Journal of Environmental Sciences 2010年第12期22卷 1954-1959页

作者： Zhilin Ran shaofeng li Junli Huang Yixing Yuan Chongwei Cui Craig Denver Williams School of Municipal & Environmental Engineering Harbin Institute of Technology Harbin 150090 China Department of Building & Environmental Engineering Shenzhen Polytechnic Institute Shenzhen 518055 China School of Applied Science University of Wolverhampton Wolverhampton WV1 1LY UK

The fluorescence staining method and scanning electron microscopy （SEM） were used to study the effect of ozone （O3） inactivating Cryptosporidium in water and cell ultrastructures variation to shed light on the mechanism of inactivation preliminarily. Results indicated that O3 had a stronger inactivating capability. When the concentration of O3 was above 3.0 mg/L and the contact time was up to 7 min, a significant inactivating effect could be achieved. The turbidity on inactivation effects was also found to be statistically significant in artificial water. With increases in turbidity, the inactivating effect decreased. Inactivation rate improved with a temperature increase from 5 to 25℃, but decreased beyond this. The inactivating capability of O3 was found to be stronger under acidic than that under alkalic conditions. When the concentration of organic matter in the reaction system was increased, the competition between Cryptosporidium and organics with O3 probably took place, thereby reducing the inactivation rate. In addition, the cellular morphology of Cryptosporidium varied with different contact times. At zero contact time, cells were rotundity and sphericity, at 60 sec they became folded, underwent emboly, and burst at 480 sec, the cell membrane of Cryptosporidium shrinked and collapsed completely.

关键词： ozone inactivation Cryptosporidium ultrastructures

An Efficient Two-Party Key Exchange Protocol with Strong Security

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Wuhan University Journal of Natural Sciences 2010年第3期15卷 267-271页

作者： DENG shaofeng li Yifa DENG Yiqun Institute of Information Engineering Information Engineering University Zhengzhou 450002 Henan China

Combined public key （CPK） cryptography does not need certificates to guarantee the authenticity of public keys and avoids the inherent key escrow problem of identity-based cryptography. Based on the efficient CPK scheme, we present an efficient three-round two-party authenticated key exchange protocol with strong security, which is provably secure in the standard model under the decisional Diffie-Hellman （DDH） assumption. The protocol can keep the session key secret from the adversary except that one party＇s ephemeral private key and static private key are all revealed to the adversary. Compared to the existing protocols, this protocol not only assures strong security but also is more efficient.

关键词： combined public key (CPK) authenticated key exchange protocol strong security standard model

Characterization of chlorine dioxide as disinfectant for the removal of low concentration microcystins

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Frontiers of Environmental Science & Engineering 2012年第1期6卷 75-81页

作者： Mingsong WU Junli HUANG Yuling ZHANG Shijie YOU shaofeng li Zhilin RAN Yu TIAN Key Laboratory of Water Resource Utilization and Environmental Pollution Control Harbin Institute of TechnologyHarbin 150090China College of Environmental Science and Engineering North China Electric Power UniversityBaoding 071003China Department of Architecture Engineering Shenzhen Polytechnic InstituteShenzhen 518055China

Microcystins, which represents one kind of cancerogenic organic compounds, is abundant in eutro- phication water. The effects of reaction factors on chlorine dioxide （C102） for removal of low-concentration Micro- cystin-LR, Microcystin-RR, and Microcystin-YR in water as well as the reaction mechanisms was investigated by using enzyme-linked immunosorbent assay （EliSA） kit and gas chromatography-mass spectrometry （GC-MS）. The results showed that MC-LR, MC-RR, and MC-YR could be efficiently decomposed by C102. The degradation efficiency was shown positively correlated to the concen- tration of C102 and reaction time; while the effect of reaction temperature and pH is slight. The kinetic constants and activation energies of the reaction ofMC-LR, MC-RR, and MC-YR with C102 are determined as 459.89, 583.15, 488.43 L.（***）I and 64.78, 53.01, ***1, respectively. As indicated by high performance liquid chromatography mass spectrometer （HPLC-MS） analysis, degradation should be accomplished via destruction of Adda group by oxidation, with the formation of dihydroxy substituendums as end products. This study has provided a fundamental demonstration of C102 serving as oxidizing disinfectant to eliminate microcystins from raw water source.

关键词： disinfection chlorine dioxide microcystins reaction mechanism

Simulation of the Subsidence and Deposition Processes of the Foreland Basin in the Southwestern Margin of Ordos

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Acta Geologica Sinica(English Edition) 1996年第3期70卷 233-245页

作者： liu shaofeng, li Sitian, Zhuang Xinguo, Jiao Yangquan and Lu ZongshengChina University of Geosciences, Wuhan China University of Geosciences W uhan

Characteristics of deformation in the thrust belt and sequence stratigraphic framework in the foreland basin, structural features of the basin margin, and the episodic thrusting are studied in this paper by combining the eastern Qilian thrust belt and the Late Triassic foreland basin on the southwestern margin of Ordos. On this basis, a geological model and a mechanical model of coupling mechanism were established for the pair of thrust belt and foreland basin, and the subsidence and deposition process of the foreland basin were simulated on given parameters.

关键词： thrust belt foreland basin sequence stratigraphic framework episodic thrusting simulation

担心二语自我是一个独立的自我——对二语动机自我系统的重新审视

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外语界 2021年第6期 72-79页

作者：于晶 shaofeng li 天津师范大学教育学部天津300387 School of Learning Developmentand Professional PracticeUniversity of AucklandAuckland 1023

本研究对新西兰高校ESL语境下443名中国留学生的英语二语动机自我开展了问卷调查。研究通过验证性因子分析揭示了担心二语自我是一个独立的自我,不是理想二语自我在同一领域的另一面,二语动机自我系统应将"担心二语自我"作为一个单独的... 详细信息

本研究对新西兰高校ESL语境下443名中国留学生的英语二语动机自我开展了问卷调查。研究通过验证性因子分析揭示了担心二语自我是一个独立的自我,不是理想二语自我在同一领域的另一面,二语动机自我系统应将"担心二语自我"作为一个单独的实体自我。据此,研究提出将Markus&Nurius(1986)可能自我理论中的"担心自我"融入D9rnyei(2005)的二语动机自我系统,望能为二语动机自我系统发展做出理论贡献。

关键词：担心二语自我二语动机自我系统 ESL语境验证性因子分析

An electrocatalyst with anti-oxidized capability for overall water splitting

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Nano Research 2018年第6期11卷 3411-3418页

作者： Chang Yu Huawei Huang Si Zhou Xiaotong Han Changtai Zhao Juan Yang shaofeng li Wei Guo Bowen An Jijun Zhao Jieshan Qiu State Key Lab of Fine Chemicals School of Chemical Engineering Liaoning Key Lab for Energy Materials and Chemical Engineering Dalian University of Technology Dalian 116024 China Key Laboratory of Materials Modification by Laser Ion and Electron Beams (Ministry of Education) Dalian University of Technology Dalian 116024 China

An anti-oxidized NiS2 electrocatalyst with improved catalytic activity was developed using a Fe-induced conversion strateg3a X-ray photoelectron spectroscopy reveals that betatopic Ni species with high valence states are present within the Fe-NiS2 matrix and relatively less oxidized layers exist on the catalyst＇s surface, indicating its greatly enhanced anti-oxidized capability. Density functional theory calculations reveal that the Ni and Fe sites on the Fe-NiS2 catalyst surface possess strong adsorption capacity toward hydroxyl ions compared with the Ni sites on NiS2. Benefiting from its unique microstructure and modulated electronic structure due to the effects of iron species, the Fe-NiS2 catalyst prepared on carbon fiber delivers a remarkably enhanced catalytic activity and superior long-life durability for overall water splitting. The present results provide an efficient strategy for the design and configuration of anti-oxidation catalysts, especially for energy storage and catalysis.

关键词： anti-oxidized catalysts metal sulfides oxygen evolution hydrogen evolution water splitting

Patterns and Cellular Mechanisms of Arm Regeneration in Adult Starfish Asterias rollestoni Bell

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Journal of Ocean University of China 2011年第3期10卷 255-262页

作者： FAN Tingjun FAN Xianyuan DU Yutang SUN Wenjie ZHANG shaofeng li Jiaxin Department of Marine Biology College of Marine Life Sciences Ocean University of China Qingdao 266003 P. R. China

To understand the mechanisms of starfish regeneration, the arms of adult starfish Asterias rollestoni Bell were amputated and their regeneration patterns and cellular mechanisms were *** was found that cells in the outer epidermis and inner parietal peritoneum near the end of the stump began to dedifferentiate 4 d after amputation. The dedifferentiated cells in the outer epidermis proliferated,migrated to the wound site and formed a thickened pre-epidermis which would then re-differentiate gradually into ma-ture *** new parietal peritoneum formed on the coelomic side of wound might be from the curvely elongated parietal peritoneum, resulting from the dedifferentiated and proliferated cells by extension. Afterwards, the proliferated cells made the outer epidermis and inner parietal peritoneum invaginate into the interior dermis and formed blastema-like structures together with induced dedifferentiated dermal cells. Most interestingly, the arm regeneration in A. rollestoni was achieved synchronously by de novo arm-bud formation and growth, and arm-stump elongation. The crucial aspects of arm-bud formation included cell dedifferentiation, proliferation and migration, while those of arm-stump elongation included cell dedifferentiation, proliferation, invagination, and arm-wall-across blastema-like structure formation. The unique pattern and cellular mechanisms of amputated arm regeneration make it easier to understand the rapid regeneration process of adult starfish. This study may lay solid foundations for the research into mo-lecular mechanisms of echinoderm regeneration.

关键词： arm regeneration blastema-like structure adult starfish Asterias rollestoni Bell

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热压烧结制备碳化钛复合材料及其性能研究

陶瓷学报 2022年第1期43卷 100-106页

作者：李少峰宁波东联密封件有限公司浙江宁波315191

采用热压烧结工艺制备了碳化钛复合材料。选用扫描电镜(SEM)观察试样的表观形貌与断口形貌,分别检测了其力学性能,以X射线衍射仪(XRD)对复合材料的成分进行了表征并对其抗氧化性能进行了分析。结果显示,在碳化钛材料中添加WC改善了其显... 详细信息

采用热压烧结工艺制备了碳化钛复合材料。选用扫描电镜(SEM)观察试样的表观形貌与断口形貌,分别检测了其力学性能,以X射线衍射仪(XRD)对复合材料的成分进行了表征并对其抗氧化性能进行了分析。结果显示,在碳化钛材料中添加WC改善了其显微结构和力学性能,WC颗粒在TiC基体材料中离散补强增韧以及金属组分的强韧化,有助于TiC复合材料综合性能的提升。试样S4在WC添加量达到15 wt.%时最优,材料的断裂面显微组织细密、晶界分布明显、裂纹扩张路线走向清晰。金属相的韧化与碳化物硬质相在基体中弥散增韧协同效应提高了TiC复合材料的韧性。力学性能分别为:维氏硬度21.7 GPa,弯曲强度1139 MPa,断裂韧性9.8 MPa·m^(1/2),相对密度99.2%。在所设定的1150℃及保温2 h条件氧化后,热压烧结工艺制备的试样表面形成了一层对基体具有保护效果的致密性氧化膜,所形成的完全氧化层层厚大概为52.3μm,过渡层层厚为22.8μm左右。

关键词：碳化钛复合材料热压烧结抗氧化性能

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