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A NOTE ON THE COMPLEX DISPERSION RELATION FOR STEADY VISCOUS SHIP WAVES

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Journal of Hydrodynamics 2005年第1期17卷 22-26页

作者： LUDong-qiang ShanghaiinstituteofAppliedMathematicsandMechanics ShanghaiUniversityShanghai200072China／／DepartmentofMechanicalEngineeringTheUniversityofHongKongHongKongChina

Based on the double Fourier integral representation for steady viscous ship waves, which involves a generic amplitude function and a complex dispersion relation, the phase function for three dimensional ship waves in the far field was asymptotically derived by means of the Lighthill two stage scheme combining the Cauchy residue theorem and the method of steepest descents, and the effect of viscosity on wavelengths was numerically investigated with the Newton iteration method. It is found that the transverse and diverging waves are elongated due to the presence of viscosity and the latter is more heavily affected and that the phase differences between the viscous transverse and diverging waves are larger than those of the corresponding inviscid waves.

关键词： free-surface wave Oseen flow viscosity complex dispersion relation

Chaos-based encryption for fractal image coding

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Chinese Physics B 2012年第1期21卷 115-126页

作者：袁正雄黄国和 Department of Electronic Engineering City University of Hong Kong

A chaos-based cryptosystem for fractal image coding is proposed. The Renyi chaotic map is employed to determine the order of processing the range blocks and to generate the keystream for masking the encoded sequence. Compared with the standard approach of fraetal image coding followed by the Advanced Encryption Standard, our scheme offers a higher sensitivity to both plaintext and ciphertext at a comparable operating efficiency. The keystream generated by the Renyi chaotic map passes the randomness tests set by the United States National institute of Standards and Technology, and so the proposed scheme is sensitive to the key.

关键词： chaos cryptography joint image compression and encryption fractal image coding

Unconventional Fluorescent and Multi-responsive Polysiloxane:Synthesis,Characterization and Biological Applications

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Chinese Journal of Polymer Science 2024年第5期42卷 579-590,I0006页

作者： Xiao-Di Li Shu-Sheng Li Xu-Bao Jiang Xiao-Li Zhu Xiang Zheng kong College of Chemistry and Chemical Engineering University of JinanJinan250022China College of Chemical Engineering Tianjin UniversityTianjin300072China Foshan(Southern china)institute for New Materials Foshan528200China

Owing to their high significance in fundamental study and diverse applications,stimuli-responsive and fluorescent polymers,particularly those with cluster-triggered emission(CTE)featured by non-conjugated chromophores,have drawn tremendous attention in recent *** this work,fluorescent and multi-responsive polysiloxane(FRPS)was synthesized by hydrolytic condensation polymerization of 3-aminopropyl methyl diethoxysilane(APMS)with 3-(N-isopropyl propionamide)iminopropyl methyl diethoxysilane(APMS-NIP),which was formed in situ through aza-Michael addition between APMS and N-isopropyl *** was not only highly sensitive to temperature,pH and CO_(2. in water,but also showed an enhanced and stimuli-adjustable fluorescence *** effects of monomer feeding,pH and CO_(2. on its lower critical solution temperature and fluorescent property were *** fluorescence emission was ascribed to CTE *** addition,FRPS was shown to be highly potential as physiological indicator for cell imaging,and for controlled release and trace detection of *** study provides therefore a type of stimuli-responsive and fluorescent material for potential applications in biomedical fields,and it is also of great significance for understanding of the fluorescence mechanism of polysiloxane-based stimuli-responsive polymers.

关键词： Polysiloxane Multi-responsiveness Cluster-triggered emission Cell imaging Controlled drug release

Monitoring and Warning of Landslides and Debris Flows Using an Optical Fiber Sensor Technology

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Journal of Mountain Science 2011年第5期8卷 728-738页

作者： PEI Huafu CUI Peng YIN Jianhua ZHU honghu CHEN Xiaoqing PEI Laizheng Department of Civil and Structural Engineering the Hong Kong Polytechnic University Hong Kong China institute of Mountain Hazards and Environment CAS Chengdu 610041 China School of Earth Sciences and Engineering Nanjing University Nanjing 210093 China

Landslides and debris flows are typical geo-hazards which occur in hilly or mountainous regions. Debris flows may result from landslides. Geotechnical instrumentation plays an important role in monitoring and warning of landslides and resulted debris flows. Traditional technologies for monitoring landslides and debris flows have certain limitations. The new optical fiber sensors presented in this paper can overcome those limitations. This paper presents two new optical fiber sensor systems: one is the Fiber Bragg Grating (FBG)-based in-place inclinometer for monitoring landslides and the other is the FBG-based column-net system for monitoring debris flows. This paper presents the calibration results of FBG-based in-place inclinometers in laboratory. It is found that the calibration results are in good agreement with theoretical results. Both the FBG-based in-place inclinometers and the FBG-based column-net system have been installed at a site in Weijiagou valley, Beichuan County, Sichuan Province of china. Some preliminary results have been obtained and reported in the paper. The advantages of the FBG monitoring systems and their potential applications are also presented.

关键词： Landslide Debris flow Fiber Bragg Grating In-place inclinometer Column-net system

Comparative analysis of astaxanthin and its esters in the mutant E1 of Haematococcus pluvialis and other green algae by HPLC with a C30 column

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Science china(Life Sciences) 2008年第12期51卷 1108-1115页

作者： PENG Juan1, XIANG WenZhou2.1, TANG QuanMing1, SUN Ni1, CHEN Feng1,3 & YUAN JianPing 4 1 South china Sea institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, china 2.institute of Oceanology, Chinese Academy of Sciences, Qingdao 2.6071, china 3 School of Biological Sciences, The university of hong kong, hong kong, china 4 institute of Oceanology & College of Life Sciences, Sun Yat-Sen university, Guangzhou 510301, china South china Sea institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China School of Biological Sciences The University of Hong Kong Hong Kong China institute of Oceanology & College of Life Sciences Sun Yat-Sen University Guangzhou 510301 China

A gradient reversed-phase high-performance liquid chromatography (HPLC) method using a C30 col-umn was developed for the simultaneous determination of astaxanthin, astaxanthin monoesters and astaxanthin diesters in the green algae Chlorococcum sp., Chlorella zofingiensis, Haematococcus plu-vialis and the mutant E1, which was obtained from the mutagenesis of H. pluvialis by exposure to UV-irradiation and ethyl methanesulphonate (EMS) with subsequent screening using nicotine. The re-sults showed that the contents of total astaxanthins including free astaxanthin and astaxanthin esters ranged from 1.4 to 30.9 mg/g dry biomass in these green algae. The lower total astaxanthin levels (2.mg/g dry biomass) were detected in the green algae Chlorococcum sp. and C. zofingiensis. The higher total astaxanthin levels (>16 mg/g dry biomass) were found in the green alga H. pluvialis and its mutant E1. It is notable that the mutant E1 is found to have considerably higher amounts of total astaxanthin (30.9 mg/g) as compared to the wild strain of H. pluvialis (16.1 mg/g). This indicates that UV-irradiation and EMS compound mutagenesis with subsequent screening using nicotine is an effective method for breeding of a high-producing astaxanthin strain of H. pluvialis. In addition, the green alga C. zofingien-sis had a remarkably higher percentage of astaxanthin diesters (76.3% of total astaxanthins) and a re-markably lower percentage of astaxanthin monoesters (18.0% of total astaxanthins) in comparison with H. pluvialis (35.5% for diesters and 60.9% for monoesters), the mutant E1 (49.1% and 48.1%) and Chlorococcum sp. (18.0% and 58.6%).

关键词： green algae Haematococcus pluvialis mutant astaxanthin HPLC C30 column

TAX EVASION:MODELS WITH SELF-AUDIT

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Journal of Systems Science & Complexity 2008年第4期21卷 487-518页

作者： Kin Keung LAI Department of Management Sciences City University of Hong Kong College of Business Management Hunan University

Different from traditional tax audit, supervision with self-audit is a combination of audit by the taxpayer himself and audit by the tax authority. This paper mainly studies a taxpayer＇s optimal policy of tax evasion under supervision with self-audit and its related properties, in order to deduce some effective suggestions and theoretical bases to restrain tax evasion. Assuming that only a certain proportion of evaded tax can be discovered when the audit is executed, the authors first formulate a static model with self-audit. This model is divided into two stages. At the first stage, taxpayers declare their taxes, then the tax authority chooses audit objects, based on a known probability, and announces the result; if the taxpayer is chosen, he will enter the second stage, during which he has a chance to pay the evaded tax and the corresponding late fees and then is audited by the tax authority. The authors show the existence and uniqueness of the optimal amount of tax evasion at the first stage and the optimal proportion to self-expose at the second stage. The authors also discuss the related properties of the interior solution, and do elasticity analyses on some parameters. Besides, the authors extend the static model into the corresponding two-period model, and study the existence and uniqueness of the solution of the extended model. Finally, under the assumption that tax evasion can only be discovered with a certain probability when the audit is executed, the authors formulate another static model with self-audit and investigate its properties.

关键词： Existence and uniqueness of the solution self-audit static model tax evasion two-period model.

research on the dynamics of the South china Sea opening:Evidence from analogue modeling

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Science china Earth Sciences 2006年第10期49卷 1053-1069页

作者： SUN Zhen1,2. ZHOU Di1, Zhong Zhihong3, XIA Bin2. QIU Xuelin1, ZENG Zuoxun4 & JIANG Jianqun5 1. CAS Key Laboratory of Marginal Sea Geology, South{2. Sea institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301,{2. 2. CAS Key Laboratory of Marginal Sea Geology, Guangzhou institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640,{2. 3. Department of Technology, Shenzhen Branch of CNOOC, Guangzhou 5102.0,{2. 4. Faculty of Earth Sciences,{2. university of Geosciences, Wuhan 430074,{2. 5. Hainan Oil & Gas Exploration Company, Liaohe Oilfield Petrochina, Panjin 12.010,{2. 1. CAS Key Laboratory of Marginal Sea Geology South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China 2. CAS Key Laboratory of Marginal Sea Geology Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China 3. Department of Technology Shenzhen Branch of CNOOC Guangzhou 510240 China 4. Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China 5. Hainan Oil & Gas Exploration Company Liaohe Oilfield PetroChina Panjin 124010 China

Independent of Indochina extrusion, the South china Sea experienced a process from passive continental rifting to marginal sea drifting. According to the fault patterns in the Beibu Gulf basin and the Pearl River Mouth basin, the continental rifting and early spreading stage from 32.to 2. Ma were controlled by extensional stress field, which shifted clockwise from southeastward to south southeastward. From 2. Ma on, the sea spread in NW-SE direction and ceased spreading at around 15.5 Ma. Integrated geological information with the assumption that the South china Sea developed along a pre-Cenozoic weakness zone, we did analogue experiments on the South china Sea evolu- tion. Experiments revealed that the pre-existing weakness zone goes roughly along the uplift zone between the present Zhu-1 and Zhu-2.depression. The pre-existing weakness zone is composed of three segments trending NNE, roughly EW and NEE, respectively. The early opening of the South china Sea is accompanied with roughly 15° clockwise rotation, while the SE sub-sea basin opened with SE extension. Tinjar fault was the western boundary of the Nansha block (Dangerous Ground), while Lupar fault was the eastern boundary of the Indochina, NW-trending rift belt known as Zengmu basin developed between above two faults due to block divergent of Indochina from Nansha. In the experiment, transtensional flower structures along NW-trending faults are seen, and slight inversion occurs along some NE-dipping faults. The existence of rigid massifs changed the orientations of some faults and rift belt, and also led to deformation concentrate around the massifs. The rifting and drifting of the South china Sea might be caused by slab pull from the proto South china Sea subducting toward Borneo and/or mantle flow caused by India-Asia collision.

关键词： South china Sea, rifting and drifting, clockwise rotation, analogue modeling, rigid massifs.

Time-dependent Ginzburg-Landau equation for lattice hydrodynamic model describing pedestrian flow

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Chinese Physics B 2013年第7期22卷 104-108页

作者：葛红霞程荣军卢兆明 Faculty of Maritime and Transportation Ningbo University Ningbo institute of Technology Zhejiang University Department of Civil and Architectural Engineering City University of Hong Kong

A thermodynamic theory is formulated to describe the phase transition and critical phenomena in pedestrian flow. Based on the extended lattice hydrodynamic pedestrian model taking the interaction of the next-nearest-neighbor persons into account, the time-dependent Ginzburg-Landau （TDGL） equation is derived to describe the pedestrian flow near the critical point through the nonlinear analysis method. The corresponding two solutions, the uniform and the kink solutions, are given. The coexisting curve, spinodal line, and critical point are obtained by the first and second derivatives of the thermodynamic potential.

关键词： pedestrian flow lattice hydrodynamic model time-dependent Ginzburg–Landau equation

Stimulus responsive fluorescent hyperbranched polymers and their applications

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Science china Chemistry 2010年第12期53卷 2409-2428页

作者： WANG Jian 1,MEI Ju 1,QIN AnJun 1,SUN JingZhi 1 & TANG Ben Zhong 1,2.1 MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering,institute of Biomedical Macromolecules,Zhejiang {2.,Hangzhou 31002.,china 2.Department of Chemistry,The hong kong {2. of Science & Technology,hong kong,china 1. MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering Institute of Biomedical Macromolecules Zhejiang University Hangzhou 310027 China2. Department of Chemistry The Hong Kong University of Science & Technology Hong Kong China

Fluorescent hyperbranched polymers (FHBPs),which combine the versatile fluorescent property with unique characteristics of hyperbranched architecture,are desirable candidates for stimulus responsive *** review demonstrates the structure and environment-dependent emission behaviors of a series of *** active FHBPs showing opposite performance to ACQ effect are used to sensitively detect explosives and a superamplification effect is *** designed FHBPs can complex with metal ions,leading to fluorescence turn-off due to complex quenching *** protonation of amino-containing FHBPs exhibits pH-dependent fluorescence responses to solution *** FHBPs containing responsive moieties are photo-and thermo-sensitive,and show potential applications as smart materials.

关键词： fluorescent hyperbranched polymer explosives and metal ions detection pH responsive optical and thermal sensitive