检索结果-南通市图书馆

Research progress in gecko locomotion and biomimetic gecko-robots

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第1期17卷 1-5页

作者： DAI Zhendong and SUN Jiurong ( institute of Bio-inspired Structure and Surface Engineering, nanjing University of Aeronautics and Astronautics, nanjing 210016, china College of Life Sciences, Peking University, Beijing 100871, china) institute of Bio-inspired Structure and Surface Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China College of Life Sciences Peking University Beijing 100871 China

Geckos are known for their excellent ability to climb walls and run on ceilings. Previous studies of the gecko's locomotive and adhesive mechanisms, its neuro-sensory and neuro-modulatory systems, its fabrication of artificial setae array, and other related developments, have inspired further research on gecko-based and gecko-like robots. Key research findings in this area are reviewed in the present paper.

关键词： gecko locomotion biomimetic modulation gecko-like robot.

One-step estimation for varying coefficient models

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Mathematics 2005年第2期48卷 198-213页

作者： TANG Qingguo & WANG Jinde Department of Mathematics, nanjing University, nanjing 210093, china institute of Sciences, PLA University of Science and Technology, nanjing 210007, china Department of Mathematics Nanjing University Nanjing China institute of Sciences PLA University of Science and Technology Nanjing China

A one-step method is proposed to estimate the unknown functions in the varying coefficient models, in which the unknown functions admit different degrees of smoothness. In this method polynomials of different orders are used to approximate unknown functions with different degrees of smoothness. As only one minimization operation is employed, the required computation burden is much less than that required by the existing two-step estimation method. It is shown that the one-step estimators also achieve the optimal convergence rate. Moreover this property is obtained under conditions milder than that imposed in the two-step estimation method. More importantly, as only one minimization operation is employed, the full asymptotic properties, not only the asymptotic bias and variance, but also the asymptotic distributions of the estimators can be derived. The asymptotic distribution results will play a key role for making statistical inference.

关键词： varying coefficient model, one-step estimation, asymptotic distribution, optimal convergence rate.

Early-Mid Ordovician brachiopod diversification in South china

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第5期48卷 662-675页

作者： ZHAN Renbin, RONG Jiayu, CHENG Jinhui & CHEN Pengfei nanjing institute of geology and Palaeontology, Chinese Academy of Sciences State Key Laboratory of Palaeobiology and Stratigraphy, nanjing 210008, china nanjing institute of geology and Palaeontology Chinese Academy of Sciences State Key Laboratory of Palaeobiology and Stratigraphy Nanjing China

Affected by paleogeographic position, paleoclimatic condition and depositional environments, the increase of the Early-Mid Ordovician brachiopod diversity of South china commenced at the beginning of the Ordovician (early Tremadoc), accelerated from the Tetra- graptus approximatus Biozone (base of Arenig), and reached its first acme in the Didymograptus eobifidus Biozone (mid early Arenig) when the number of brachiopod genera was over 7 times as great as that at the start of the Ordovician. This was the first radiation in the history of brachiopod macroevolution in South china, which occurred nearly 5 graptolitic biozones earlier than the global trend of the great Ordovician biodiversification (in the lower part of the Undulograptus austrodentatus Biozone). It is also characterized by (1) the origination or first occurrences of some major groups, such as the punctate dalmanelloids and the pseudopunctate stro- phomenoids including Plectambonitoidea (cardinal process simple or absent) and Stro- phomenoidea (cardinal process bilobed) in South china; (2) niche expansion, particularly in the first occupation of deeper water benthic regimes by the Euorthisina-Nocturnellia Association developed at Houping, Chengkou, northern Chongqing; and (3) the differentiation of brachiopod faunas under different environmental conditions. The gradual and increasing separation from Gondwana may have been one of the factors responsible for the radiation in South china.

关键词： biodiversity, evolutionary radiation, brachiopods, Early-Mid Ordovician, South china.

Types, Metallogenic Environments and Characteristics of Temporal and Spatial Distribution of Copper Deposits in china

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1989年第1期63卷 79-92页

作者： Wang Zhitian and Qin Kezhang Beijing institute of geology for mineral resources, CNNC, Beijing Zhang Zhongmin Beijing institute of geology for mineral resources CNNC Beijing

Based upon a comprehensive study of 123 copper deposits in china. this paper reaches the following conclusions: 1. The crust in china was solidified pretty late; with the accretion of the plate, the copper mineralization moved towards its margin in space and became successively younger in age. 2. The major copper ore types ever found in the world have mostly been discovered in china, in which the porphyry type seems to be the most important and the massive sulfide type in the transitional bed between marine clastic and carbonate rocks is clearly defined. 3. Carbonate strata are widespread in china and their deposition lasted for a long geological period, so the proportion of copper deposits occurring in them is large as compared with other parts of the world. 4. Seven metallogenic epochs can be recognized, in which the Mesozoic one plays the leading role and the middle(late) Palaeozoic and Cenozoic ones are next in importance. mineralization was comparatively simple in the early geological period. and became diversified later on. In the early epochs copper deposits related to basaltic magmatism and metamorphosed marine sediments predominated, whereas in the later epochs those related to granitic magmatism and continental sedimentation were dominant. 5. There exist in china thirteen metallogenic provinces, of which the Lower Yangtze downwarping belt, Sanjiang fold system, Jiangnan axis and Xikang-Yunnan axis are of greater significance. 6. The crustal mobility in china was rather pronounced, the polycyclic evolution of the crust has resulted in such obvious phenomena as the inheritance of mineralization, the coexistence of various types and the superposition of different genetic types.

关键词： Metallogenic Environments and Characteristics of Temporal and Spatial Distribution of Copper Deposits in china Types

A　40　km　Fiber－optic　Microwave　Subcarrier　Multiplexing　Transmission　System　for　Multi－channel　FM－TV

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Lasers 1996年第5期B5卷 470-474页

作者： ZHANG Zhengxian LIN Zhiyuan LI Zhitang Xu Jie (Communications Engineering institute, nanjing 210016, china Southeast Universtiy, nanjing 210018, china Wuhan Research institute of Post and Telecommunications, Wuhan 430074, china) china Southeast Univ Nanjing China

Ａ４０ｋｍＦｉｂｅｒ－ｏｐｔｉｃＭｉｃｒｏｗａｖｅＳｕｂｃａｒｒｉｅｒＭｕｌｔｉｐｌｅｘｉｎｇＴｒａｎｓｍｉｓｓｉｏｎＳｙｓｔｅｍｆｏｒＭｕｌｔｉ－ｃｈａｎｎｅｌＦＭ－ＴＶＺＨＡＮＧＺｈｅｎｇｘｉａｎ；ＬＩＮＺｈｉｙ... 详细信息

Ａ４０ｋｍＦｉｂｅｒ－ｏｐｔｉｃＭｉｃｒｏｗａｖｅＳｕｂｃａｒｒｉｅｒＭｕｌｔｉｐｌｅｘｉｎｇＴｒａｎｓｍｉｓｓｉｏｎＳｙｓｔｅｍｆｏｒＭｕｌｔｉ－ｃｈａｎｎｅｌＦＭ－ＴＶＺＨＡＮＧＺｈｅｎｇｘｉａｎ；ＬＩＮＺｈｉｙｕａｎ；ＬＩＺｈｉｔａｎｇ；ＸｕＪ...

关键词： fiber communication microwave subcarrier multiplexing multi-channel FMTV

PREDICTION OF THE AERODYNAMIC PERFORMANCE OF HORIZONTAL AXIS WIND TURBINES IN CONDITION OF UNIFORM WIND

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 1991年第2期6卷 207-213页

作者： Wang Tongguang Tang Ruiyuan nanjing Aeronautical institute nanjing 210016, P.R. of china

The classical momentum-blade element theory is improved by using the empirical formula while part of rotor blades enters into the turbulent wake state, and the performance of a horizontal-axis wind turbine (HAWT) at all speed ratios can be predicted. By using an improved version of the so-called secant method, the convergent solutions of the system of two-dimensional equations concerning the induced velocity factors a and a' are guaranteed. Besides, a solving method of multiple solutions for a and a' is proposed and discussed. The method provided in this paper can be used for computing the aerodynamic performance of HAWTs both ofrlow solidity and of high solidity. The calculated results coincide well with the experimental data.

关键词： Wind Axis PREDICTION OF THE AERODYNAMIC PERFORMANCE OF HORIZONTAL AXIS WIND TURBINES IN CONDITION OF UNIFORM WIND

Morphology and reaction force of toes of geckos freely moving on ceilings and walls

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第6期53卷 1688-1693页

作者： WANG ZhouYi1,2,GU WenHua1,2,WU Qiang1,2,JI AiHong1 & DAI ZhenDong1 1 institute of Bio-inspired Structure and Surface Engineering,nanjing University of Aeronautics and Astronautics,nanjing 210016,china 2 College of Mechanical and Electrical Engineering,nanjing University of Aeronautics and Astronautics,nanjing 210016,china institute of Bio-inspired Structure and Surface Engineering Nanjing University of Aeronautics and Astronautics Nanjing China College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing China

The 3-dimensional interactions between toes of a gecko and substrates (ceilings or walls) were measured when it moves on ceilings or walls by using a 3-dimensional force measuring array,and the correspondent morphology of the gecko toes was recorded by a high speed *** study aims to understand the relationship between adhesive and shear forces generated by the toes of the gecko and the locomotion behavior when it walks on walls and *** showed that shear force is along the toe-only 12.6° and 3.1° away from the toe for wall-climbing and ceiling-crawling,respectively while the adhesion is big enough to balance the body weight and *** shear forces generated by the first and the fifth toes are in opposite directions;this redundant force increases the reliability of adhesion and stability of *** support angles of toes are equal approximately for ceiling-crawling and *** study greatly inspires the design of a gecko-like robot.

关键词： reaction force of toe morphometrics ceiling redundant force gecko-like robot

SOME ROTORDYNAMIC PROBLEMS IN SMALL TURBO—ENGINES

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 1992年第1期 52-58页

作者： Huang Tai-ping (nanjing Aeronautical institute, nanjing, 210016)

Rotordynamics in small turbo-engines is a very important topic owing to their highrotating speeds and small sizes. In this paper, some rotordynamic problems in smallturbo-engines have been discussed and the approaches to solving these problems have beenanalyzed briefly. Numerical and experimental results show that the analysis is valuableand reliable.

关键词： mode ENGINES SOME ROTORDYNAMIC PROBLEMS IN SMALL TURBO

Ore-forming fluid and mineralization of Caijiaying and Dajing polymetallic ore deposits

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Earth Sciences 2004年第2期47卷 97-107页

作者： WANG Lijuan,WANG Jingbin, WANG Yuwang & ZHU Heping1. Key Laboratory of mineral resources, institute of geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, china 2. Beijing institute of geology for mineral resources, Beijing 100012, china Correspondence should be addressed to Wang Lijuan (email: wlj@***) Key Laboratory of mineral resources Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China Beijing institute of geology for mineral resources Beijing China

Fluid inclusions from the Dajing and Caijiaying deposits have nearly the same homogenization temperature. Correlation between temperature and salinity shows that both Sn- and Cu-bearing fluids Sn and Cu were present in the Dajing deposit but only one kind of fluids continuously evolved in the Caijiaying deposit. Study on rare earth elements (REE) in ancient fluid from the inclusions indicates that the fluid of Sn mineralizing stage in Dajing was derived from remelting magma of the continental crust, and the fluid of Cu-Pb-Zn mineralizing stage in the Dajing deposit and the fluid of Cu-Pb-Zn mineralization in the Caijiaying deposit were derived from the mantle. It is concluded that the Cu-Pb-Zn mineralizations in the Dajing and Caijiaying deposits resulted from the identical tectono-thermal event of magma-fluids induced by Mesozoic tectonic transition and extension in the eastern part of North china Craton.

关键词： Caijiaying, Dajing, Mesozoic tectonic transition, ore-forming fluid, REE.