检索结果-南通市图书馆

Milestone of the meridian science──970th anniversary of the Chinese Bronze Statue of Meridian

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第5期43卷 353-362页

作者： ZHANG Renji College of Life Sciences, Peking University, Beijing 100871, China College of Life Sciences Peking University Beijing 100871 China

For more than a thousand years, Chinese people were aware of the transmitted sensations by the application of needles on the body surface. This practice is called acupuncture. Acupuncture had been recorded and transcribed in writings and in drawings, until finally the acupoints were inscribed onto a bronze statue. The bronze statue was called the Meridian Figure. Deeply embodied in the bronze statue is a tripartite confrontation-prism representation of the humans body. This concept was a great scientific achievement in ancient China. The author traces the history of Meridian science described in traditional Chinese medical terms. Then he explores a clear analogy of the meridian pathway (MP) phenomenon. In a model system, by using a simple segmental in vertebrate, certain parallels can be demonstrated with the meridian concept. For example, the author demonstrated a clear correlation rule among the central mechano-sensory channels, and characteristics of positional discrimination in individual nerve cells from different receptive field inputs. The evidence suggests that the MP phenomenon is an objective neurobiological response. To clarify the research objective in this paper, the author suggests that the MP is a bi-directional pathway along which a positional message signal is transmitted. This phenomenon is evoked by physical stimulation, transmitted linearly across the human body segments, and is perceived by the brain. The MP consists of low resistance paths, is connected by the liquid media contained in the apposite membranous structure. At the cellular level, the regulation functions of MP must pass through along this low resistance path. Two aspects of the modern Meridian research are the functional regulation and the mechanism of intercellular liquid modulation at the nanometer level.

关键词： meridian pathway tripartite confrontation-prism coordinate position discriminative recognition apposite membranous structure.

Global periodic attractor for a model of forest with diffusion and seasonal effects

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1997年第24期42卷 2046-2047页

作者： LIN YuanquDepartment of Mathematics, Peking University, Beijing 100871, China Department of Mathematics Peking University Beijing 100871 China

where γ（v） = a（v- b）2 + c with positive a, b, c. As a simple mathematical model ofmono-species forest with two age classes it takes account of seed production and dispersal,where u denotes the density of "young" tree, v denotes the density of "old" tree, and ω de-notes the density of air-borne seeds; α,β,δ and d are seed production, deposition, establish-ment and diffusion rates respectively; f and h are coefficients of aging and mortality of "old"tree respectively. （1）p（t）≡0 was first presented and was then reduced to a lower-dimensionalreaction-cross-diffusion model to study travelling wave solutions in ref. [1]. We assume herethat p （t） is a periodic function of period T and 0≤p（t）≤pM, considering the seasonal ef-fects of winds, weather conditions, temperature, etc.. We consider （1） under the initial con-

关键词： age-structured forest model equivalent norm invariant rectangle global periodic attractor.

Kinetic characteristics of continuous flow polymerase chain reaction chip: A numerical investigation

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2010年第7期53卷 1967-1972页

作者： WANG ShiYing1 & WANG Wei2,3 1 School of Physics, Peking University, Beijing 100871, China 2 Institute of Microelectronics, Peking University, Beijing 100871, China 3 National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Beijing 100871, China School of Physics Peking University Beijing China Institute of Microelectronics Peking University Beijing China National Key Laboratory of Science and Technology on Micro/Nano Fabrication Beijing China

Continuous flow PCR (polymerase chain reaction) chip holds impressive advantages compared to micro chamber PCR chip. In order to have better understanding of kinetic characteristics of continuous flow PCR chip, a comprehensive mathematical model is presented in this paper, including melting, annealing and extension phases of a typical PCR process which has the essence of a convection-diffusion-reaction system. Using this model, we can simulate the PCR process in series of reaction cycles. Numerical results show that the average sample velocity plays a significant role in affecting the amplification efficiency. Also, appropriate combination of the PCR mixture is important for high-quality DNA amplification. Giving a large initial DNA concentration range, the continuous flow PCR scheme holds excellent real-time detection ability theoretically. The present numerical model bridges the temperature distribution to the real DNA amplification, and thereby is able to successfully predict continuous flow PCR properties which are important for the chip design.

关键词： continuous flow PCR chip numerical simulation convection-diffusion-reaction system

Hausdorff dimension of Julia set of a polynomial with a Siegel disk

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2006年第9期49卷 1284-1296页

作者： SHEN Liang LMAM, School of Mathematical Sciences, Peking University, Beijing 100871, China LMAM School of Mathematical Sciences Peking University Beijing 100871 China

Let f(z) = e2πiθz(1+z/d)d,θ∈R\Q be a polynomial. Ifθis an irrational number of bounded type, it is easy to see that f(z) has a Siegel disk centered at 0. In this paper, we will show that the Hausdorff dimension o... 详细信息

关键词： Hausdorff dimension Siegel disk porous set

Geodesic uniqueness problem in infinite-dimensional Teichmuller spaces

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1997年第15期42卷 1256-1261页

作者： GUO HuiSchool of Mathematical Science, Peking University, Beijing 100871, China School of Mathematical Science Peking University Beijing China

LET[μ] be a point in a Teichmuller space T（Γ） and [μ]≠[0]. When T（Γ） is finite-di-mensional, the extremal Beltrami differential in [μ]is unique and the geodesic segment α:[tμ0] （0≤t≤1） is the unique geodesic segment joining [0] and [μ], where μ0 is the uniqueextremal Beltrami differential in [μ]. However, when T（Γ） is infinite-dimensional, [μ]

关键词： infinite-dimensional Teichmiiller spaces geodesic segments extremal Beltrami differentials Ahlfors’ (quasi- )N-class.

A new Early Cretaceous lizard with well-preserved scale impressions from western Liaoning, China

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第2期15卷 67-73页

作者： JI Shu’an*(School of Earth and Space Sciences, Peking University, Beijing 100871, China) Sch. of Earth and Space Sci. Peking Univ. Beijing 100871 China

A new small lizard, Liaoningolacerta brevirostra gen. et sp. nov., from the Early Cretaceous Yixian Formation of western Liaoning is described in detail. The new specimen was preserved not only by the skeleton, but also by the exceptionally clear scale impressions. This lizard can be included within the taxon Scleroglossa based on its 26 or more presacrals, cruciform interclavicle with a large anterior process, moderately elongated pubis, and slightly notched distal end of tibia. The scales vary evidently in size and shape at different parts of body: small and rhomboid ventral scales, tiny and round limb scales, and large and longitudinally rectangular caudal scales that constitute the caudal whorls. This new finding provides us with more information on the lepidosis of the Mesozoic lizards.

关键词： new genus Squamata skeleton lepidosis Early Cretaceous western Liaoning

Interdecadal variations in global climate and earth rotation rate

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 Science Bulletin 1997年第18期42卷 1557-1560页

作者： QIAN WeihongDepartment of Geophysics, Peking University, Beijing 100871, China Department of Geophysics Peking University Beijing 100871 China

A science plan for future 15 a, 'A Study of Climate Variability and Predictability'(CLIVAR), was published by WMO in 1996. As the plan treated interdecadal climatic variability as a sub-plan, it showed that this problem is very important. By the implementation of 'Tropical Ocean and Global Atmosphere' (TOGA) 10-a plan during 1985—1994, the interdecadal variability that occurred in ENSO (El Nino/Southern Oscillation) ocean-atmosphere interaction has been found. This variability made the traditional ENSO prediction pattern useless

关键词： interdecadal variation climate prediction sea surface temperature earth rotation rate.

The driving force for development of IC and systemin future: Reducing the power consumption andimproving the ratio of performance to powerconsumption

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2011年第5期54卷 915-935页

作者： WANG YangYuan Institute of Microelectronics, Peking University, Beijing 100871, China 1. Institute of Microelectronics Peking University Beijing 100871 China

With the development of information technology, integrated circuits (IC) and system which target high performance and low power consumption have widely penetrated to all the aspects of national economy, national defense construction and people’s life. With the continuous increase in IC integration density, the power consumption is becoming the limiting factor. It turns out that the driving force of the future IC and system development is the reduction of the power consumption and improvement of the performance/power ratio. The Moore’s Law is inherently the law for the technology and economic development, and has served as the guideline of the IC development for half a century. However, with the scaling down of IC feature size and the corresponding increased integration density, it is progressively approaching the physical limitation. Moore’s Law will gradually complete its historic mission and it will be replaced by a law of reducing the power consumption while ensuring the performance requirements for IC, SoC and SiP performance, law of improving the performance/power ratio. This paper will discuss the related research topics on Green micro/nanoelectronics, including low-power design, novel low-power devices, manufacturing processes for low power applications and related micro/nano electromechanical systems.

关键词： power consumption IC technology

Phytolith assemblages and their implications from cal soils of Yingyang site in Dengfeng County, Henan Province

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 Science Bulletin 1997年第1期42卷 57-61页

作者： JIANG QinhuaDepartment of Geology, Peking University, Beijing 100871, China Depmment of Geology Peking University Beijing China

THE central plain of China has been considered as the cradle of the Chinese people, as is indicated by the abundant archaeological finds during the last 60 years. As a supplementary study to the archaeological excavation at Yingyang site of Dengfeng County, phytolith analysis was carried out. The Yingyang neolithic site is located in the south of the North China Plain and at the upper reaches of the Yinghe River, which belongs to the Huaihe drainage system, within

关键词： Yingyang site archaeological soils phytolith analysis paleoenvironment.