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science China(Technological sciences) 2005年第z1期48卷 1-17页

作者： LI Shihai1, LIAN Zhenzhong1,2 & J. G. Wang3.1. institute of Mechanics, Chinese Academy of sciences, Beijing 100080, China 2. Graduate School, Chinese Academy of sciences, Beijing 100060, China {3., national university of singapore, singapore 119260 Chinese Acad Sci Inst Mech Beijing 100080 Peoples R China Chinese Acad Sci Grad Sch Beijing 100060 Peoples R China Natl Univ singapore Trop Marine Sci Inst Singapore 119260 Singapore

This paper studies the stability of jointed rock slopes by using our improved three-dimensional discrete element methods (DEM) and physical modeling. Results show that the DEM can simulate all failure modes of rock slopes with different joint configurations. The stress in each rock block is not homogeneous and blocks rotate in failure development. Failure modes depend on the configuration of joints. Toppling failure is observed for the slope with straight joints and sliding failure is observed for the slope with staged joints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considering the joints in rock masses, the LEM predicts much higher factor of safety than physical modeling and DEM. The failure mode and factor of safety predicted by the DEM are in good agreement with laboratory tests for any jointed rock slope.

关键词： rock masses, slope stability, DEM simulation, block size effect, joints configuration effect, limit equilibrium method.

Experimental and discrete element numerical analysis of side slope instability induced by fissure water underlying impervious bed

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science China(Technological sciences) 2005年第z1期48卷 65-80页

作者： LIU Bingshan1, LI Shihai1, ZHANG Lei1,2 & WANG Jianguo3.. institute of Mechanics, Chinese Academy of sciences, Beijing 100080, China 2. Graduate School, Chinese Academy of sciences, Beijing 100060, China {3., national university of singapore, 10 Kent Ridge Crescent, singapore 119260 Chinese Acad Sci Inst Mech Beijing 100080 Peoples R China Chinese Acad Sci Grad Sch Beijing 100060 Peoples R China Natl Univ singapore Trop Marine Sci Inst Singapore 119260 Singapore

When the sliding mass contains impervious bed, rainfall can infiltrate into mountain via crevices and form higher artesian aquifer at impervious bed inferior. This will decrease slip resistance and increase sliding forces of the sliding mass, thus lowering the safety factor, and inducing landslide disasters. In this paper, a landslide experimental apparatus is designed for experimental studies on the mechanism of this type of landslides. Meanwhile, the non-dimensional parameters in the model experiment are taken into account using dimensional analysis. The experimental results show that (1) the ratio of the cleft water pressure to the overlying pressure is a crucial parameter affecting the stability of the slope; (2) when the shut-in pressure reaches 80% of the normal component of the pressure on the slip surface made up of rock and soil, landslide will occur; (3. the whole slope will start to slide when the shut-in pressure is equal to the normal component of the pressure formed by the overlying rock and soil on the upper 3.% area. In this article, a discrete element method simulation is used to investigate the influence of cleft water pressure and shearing strength on the landslide stability. It can be concluded that the critical value of Ccr, ?cr, which determines the slide mass stability, increases with the increase of the water pressure; if the water pressure reaches a high level, the stability of the slide mass depends mainly on C, while the influence of ? becomes smaller than C.

关键词： impervious bed, rainfall infiltration, pore water pressure, landslide experiment, displacement monitor, discrete element method.

Stochastic structural model of rock and soil aggregates by continuum-based discrete element method

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science China(Technological sciences) 2005年第z1期48卷 95-106页

作者： WANG Yuannian1, ZHAO Manhong1, LI Shihai1 & J.G. Wang21. institute of Mechanics, Chinese Academy of sciences, Beijing 100080, China 2. tropical {3. science institute, national university of singapore, 10 Kent Ridge Crescent, singapore 119260 1. institute of Mechanics Chinese Academy of Sciences 100080 Beijing China 2. Tr?pical marine science institute National University of Singapore 10 Kent Ridge Crescent 119260 Singapore

This paper first presents a stochastic structural model to describe the random geometrical features of rock and soil aggregates. The stochastic structural model uses mixture ratio, rock size and rock shape to construct the microstructures of aggregates, and introduces two types of structural elements (block element and jointed element) and three types of material elements (rock element, soil element, and weaker jointed element) for this microstructure. Then, continuum-based discrete element method is used to study the deformation and failure mechanism of rock and soil aggregate through a series of loading tests. It is found that the stress-strain curve of rock and soil aggregates is nonlinear, and the failure is usually initialized from weaker jointed elements. Finally, some factors such as mixture ratio, rock size and rock shape are studied in detail. The numerical results are in good agreement with in situ test. Therefore, current model is effective for simulating the mechanical behaviors of rock and soil aggregates.

关键词： CDEM, rock and soil aggregate, mixture ratio.

Inertial theory of the mean Hadley circulation under the condition of nonstatic equilibrium

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science China Earth sciences 2006年第5期49卷 546-553页

作者： CHAO Jiping1 & LIU Fei2,3.1. national marine Environmental Forecasting Center, Beijing 100081, China 2. Key Laboratory Regional Climate-Environment for Temperate East Asia, institute of Atmospheric Physics, Chinese Academy of {3.s, Beijing 100029, China 3. Graduate university of Chinese Academy of {3.s, Beijing 100049, China 1. national marine Environmental Forecasting Center Beijing 100081 China 2. Key Laboratory Regional Climate-Environment for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 3. Graduate university of Chinese Academy of sciences Beijing 100049 China

tropical atmosphere is divided into two layers, the layer near the ground is the planet boundary layer, where the motion is linear, if the radiation equilibrium temperature is given at the top of the boundary layer, the vertical motion there can be obtained. It is the non-viscous ideal atmos- pheric layer above the boundary one, where the motion is nonlinear. After getting the conservation laws of angular momentum, potential temperature and potential vortex, the inertial theory of the Hadley circulation driven by the vertical motion of the boundary layer is established, followed by sev- eral examples of its application.

关键词： Hadley circulation, inertial theory, conservation laws of angular momentum, potential temperature and potential vortex.

Field measurement and analysis of turbulence coherence for Typhoon Nuri at Macao Friendship Bridge

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science China(Technological sciences) 2010年第10期53卷 2647-2657页

作者： SONG LiLi1, PANG JiaBin2, JIANG ChengLin3. HUANG HaoHui3.& QIN Peng3.1 Guangzhou institute of tropical and marine Meteorology, CMA, Guangzhou 510080, China 2 Tongji {3., Shanghai 200092, China 3.Guangdong Climate Centre, Guangzhou 510080, China 1. Guangzhou institute of tropical and marine Meteorology CMA Guangzhou 510080 China2. Tongji University Shanghai 200092 China3. Guangdong Climate Centre Guangzhou 510080 China

For the purpose of investigating the turbulent and spatial coherent characteristics of strong wind during typhoon landing period,two 3.dimensional ultrasonic anemometer stations were set up 3. m horizontally apart on the Macao Friendship Bridge to caputure the turbulent wind velocities of Typhoon Nuri. Based on the reliable and representative field measured data,the mean wind speed and direction,turbulence intensity,turbulence integral scale,turbulence power spectra,spatial correlation coefficient and coherence function were statistically evaluated. The field measurement analysis have presented the following results: 1) Two anemometer stations provided consistent results. The mean wind speed variation in time domain presented typical M-shape curves. The strong wind (10-minute mean wind speed higher than 8th grade in Beaufort wind scale) direction changed in a big range up to 122-degrees-angle,indicating the field measurements scoped over the typhoon landing period. 2) The ratio of the longitudinal,lateral and vertical turbulence intensities of the strong wind in the typhoon eye wall region was 1:0.96:0.3.. Compared with the code defined ratio 1:0.88:0.5,the lateral component was larger and the vertical component was smaller. 3. The value of integral scale increased when the eye wall of Typhoon Nuri passed over the field measurement site. Before the center of Typhoon Nuri arrived,the integral scale of the strong typhoon wind was about twice compared with that for the non-typhoon wind. 4) The spatial correlation of the turbulent wind,coherence function curve and the decay factor had significant differences at different times during the typhoon process. In the eye wall of the typhoon,the horizontal spatial correlation was relatively strong and horizontally spatial correlation spectrum decayed slower with frequency increase. The minimum regressed coefficient C in coherence function model was 4.67,which is lower than the code defined low limit. The maximum decay factor w

关键词： typhoon field measurement and analysis turbulence characteristics coherence spectral function

A three-dimensional variational ocean data assimilation system:Scheme and preliminary results

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science China Earth sciences 2006年第11期49卷 1212-1222页

作者： ZHU Jiang1,2, ZHOU Guangqing1, YAN Changxiang1, FU Weiwei1 & YOU Xiaobao1,3.1. International Center for Climate and Environment sciences, institute of Atmospheric Physics, Chinese Academy of sciences, Beijing 100029, China 2. Jiangsu Key Laboratory of Meteorological Disaster, Nanjing university of Information science and Technology, Nanjing 210044, China 3. Beijing institute of Applied Meteorology, Beijing 100029, China 1. International Center for Climate and Environment sciences Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 2. Jiangsu Key Laboratory of Meteorological Disaster Nanjing University of Information Science and Technology Nanjing 210044 China 3. Beijing institute of Applied Meteorology Beijing 100029 China

A new 3.VAR-based Ocean Variational Analysis System (OVALS) is developed. OVALS is capable of assimilating in situ sea water temperature and salinity observations and satellite altimetry data. As a component of OVALS, a new variational scheme is proposed to assimilate the sea surface height data. This scheme considers both the vertical correlation of background errors and the nonlinear temperature-salinity relationship which is derived from the generalization of the linear balance constraints to the nonlinear in the 3.VAR. By this scheme, the model temperature and salinity fields are directly adjusted from the altimetry data. Additionally, OVALS can assimilate the temperature and salinity profiles from the ARGO floats which have been implemented in recent years and some temperature and salinity data such as from expendable bathythermograph, moored ocean buoys, etc. A 21-year assimilation experiment is carried out by using OVALS and the tropical Pacific circulation model. The results show that the assimilation system may effectively improve the estimations of temperature and salinity by assimilating all kinds of observations. Moreover, the root mean square errors of temperature and salinity in the upper depth less than 420 m reach 0.63. and 0.3. psu.

关键词： data assimilation, 3.VAR, sea surface height, ARGO floats.

Forcing mechanism of the Pleistocene east Asian monsoon variations in a phase perspective

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science China Earth sciences 2005年第10期48卷 1708-1717页

作者： TIAN Jun1,2, WANG Pinxian1, CHENG Xinrong1, WANG Rujian1 & SUN Xiangjun1,3.1. State Key Laboratory of marine Geology, Tongji university, Shanghai 200092, China 2. institute of Geology and Geophysics, Chinese Academy of {3.s, Beijing 100029, China 3. institute of Botany, Chinese Academy of {3.s, Beijing 100093. China State Key Laboratory of marine Geology Tongji university Shanghai China institute of Geology and Geophysics Chinese Academy of sciences Beijing China institute of Botany Chinese Academy of sciences Beijing China

The deep sea records from the ODP Sites 1143.and 1144 in the northern and southern South China Sea (SCS), including foraminiferal δ 18O and δ 13., Opal% and pollen percentage, reveal that the variations of the east Asian monsoon have been closely correlated with the variations of the Earth’s orbital parameters (eccentricity, obliquity and precession) and the global ice volume on orbital scale. All the monsoonal proxies show strong 100 ka, 41 ka and 23.ka cycles. Although G. ruber δ 13. of Site 1143.is coherent with the ETP (ETP= normalized (eccentricity + obliquity-precession) at eccentricity, obliquity and precession bands, most of the coherent relationship focuses on the precession band, and the other monsoonal proxies are coherent with the ETP only at the precession band, which indicate that precession dominates the Pleistocene tropical climate changes. The phase relationship of the monsoonal proxies with the foraminiferal δ 18O implies that the global ice volume changes have played a significant role in modulating the east Asian monsoon climate, at least dominating the winter monsoon. This forcing mechanism of the east Asian monsoon is apparently different from that of the Indian ocean mon-soon. The variations of the east Asian monsoon at the precession band, at least that of the winter monsoon, have been controlled not only by the sensible heating but also by the latent heating of the surface water in the South China Sea.

关键词： South China Sea, ODP, east Asian monsoon, orbital forcing, global ice volume.

Possible mechanism of the effect of convection over Asian-Australian “land bridge” on the East Asian summer monsoon onset

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science China Earth sciences 2006年第11期49卷 1223-1232页

作者： HE Jinhai1, WEN Min2, DING Yihui3.& ZHANG Renhe2 1. Jiangsu Key Laboratory of Meteorological Disaster (KLME), Nanjing institute of Meteorology, Nanjing university of Informa- tion science and Technology, Nanjing 210044, China 2. State Key Laboratory of Severe Weather (LaSW), Chinese Academy of Meteorological sciences, Beijing 100081, China 3. national Climate Center, Chinese Meteorological Administration, Beijing 100081, China 1. Jiangsu Key Laboratory of Meteorological Disaster (KLME) Nanjing Institute of Meteorology Nanjing University of Information Science and Technology Nanjing 210044 China 2. State Key Laboratory of Severe Weather (LaSW) Chinese Academy of Meteorological Sciences Beijing 100081 China 3. national Climate Center Chinese Meteorological Administration Beijing 100081 China

The Asian-Australian “land bridge” is an area with the most vigorous convection in Asian monsoon region in boreal spring, where the onset and march of convection are well associated with the onset of East Asian summer monsoon. The convection occurs over Indo-China Peninsula as early as mid-April, which exerts critical impact on the evolution of monsoon circulation. Before mid-April there are primarily sensible heatings to the atmosphere over Indo-China Peninsula and Indian Peninsula, so the apparent heating ratios over them decrease with height. However, after mid-April it changes into latent heating over Indo-China Peninsula due to the onset of convection, and the apparent heating ratio increases with height in mid- and lower troposphere. The vertical distribution of heating ratio and its differences between Indo-China Peninsula and Indian Peninsula are the key factors leading to the splitting of boreal subtropical high belt over the Bay of Bengal. Such mechanism is strongly supported by the fact that the evolution of the vertical heating ratio gradient above Indo-China Peninsula leads that of 850 hPa vorticity over the Bay of Bengal. Convections over Indo-China Peninsula and its surrounding areas further increase after the splitting. Since then, there is a positive feedback lying among the convective heating, the eastward retreat of the subtropical high and the march of monsoon, which is a possible mechanism of the advance of summer monsoon and convection from Indo-China Peninsula to South China Sea.

关键词： Asian-Australian 'land bridge', tropical convection, Indo-China Peninsula, the splitting of boreal subtropical high belt, East Asian summer monsoon onset.

Temperature dependence of circular DNA topological states and a solution to a single molecular experiment problem

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生物物理学报 2009年第S1期25卷 296-297页

作者： Yanhui Liu1, Hu Chen2, Lin Hu1, Zhong-Can Ou-Yang3. and Jie Yan2 1.Guizhou university, College of science, Guiyang, 550025 2.national university of singapore, Department of Physics, science Drive 3. singapore, 117542 3.The institute of Theoretical Physics, Chinese Academy of sciences, Beijing, China, 100080

Circular double stranded DNA has different topological states which are defined by their linking numbers. Equilibrium distribution of linking numbers can be obtained by closing

关键词： DNA Temperature dependence of circular DNA topological states and a solution to a single molecular experiment problem

Preparation of grain size controlled boron-doped diamond thin films and their applications in selective detection of glucose in basic solutions

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science China Chemistry 2010年第6期53卷 1378-1384页

作者： ZHAO JianWen1,2,WANG JinLiang3.ZHI JinFang3.& ZHANG ZhiMing4 1College of Chemistry and Chemical Engineering,Jishou university,Jishou 416000,China 2Schools of Materials science and Engineering,Nanyang Technological university,63.798,{3. 3.aboratory of Organic Optoelectronic Functional Materials and Molecular Engineering,Technical institute of Physics and Chemistry & Graduate university of Chinese Academy of sciences,Beijing 100080,China 4Research institute of Micro-Nano science and Technology,Shanghai Jiao Tong university,Shanghai 20003.,China 1. College of Chemistry and Chemical Engineering Jishou University Jishou 416000 China2. Schools of Materials Science and Engineering Nanyang Technological University 639798 Singapore Singapore3. Laboratory of Organic Optoelectronic Functional Materials and Molecular Engineering Technical Institute of Physics and Chemistry & Graduate University of Chinese Academy of Sciences Beijing 100080 China4. Research Institute of Micro-Nano Science and Technology Shanghai Jiao Tong University Shanghai 200030 China

Boron-doped diamond (BDD) thin films with different crystal grain sizes were prepared by controlling the reacting gas pressure using hot filament chemical vapor deposition (HFCVD).The morphologies and structures of the prepared diamond thin films were characterized by scanning electron microscopy (SEM) and Raman *** electrochemical responses of K4Fe(CN)6 on different BDD electrodes were *** results suggested that electron transfer was faster at the boron-doped nanocrystalline diamond (BDND) thin film electrodes in comparison with that at other BDD thin film *** prepared BDD thin film electrodes without any modification were used to directly detect glucose in the basic *** results showed that the as-prepared BDD thin film electrodes exhibited good selectivity for detecting glucose in the presence of ascorbic acid (AA) and uric acid (UA).The higher sensitivity was observed on the BDND thin film grown on the boron-doped microcrystalline diamond (BDMD) thin film surface,and the linear response range,sensitivity and the low detection limit were 0.25–10 mM,189.1 μA mmol-1 cm-2 and 25 μM (S/N=3. for glucose in the presence of AA and UA,respectively.

关键词： diamond thin films electrochemical properties selective glucose detection