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Chinese Journal of Lasers 1999年第4期8卷 3-5页

作者： YAO Minyu ZHANG Jianfeng WU Jian CHEN Minghua WANG Dapeng LOU Caiyun GAO Yizhi ZHOU Bingkun (Department of Electronic Engineering, Tsinghua University, Beijing 100084, China) Received sep. 24, 1998 Revised manuscript received Jan. 22, 1999 清华大学电子工程系北京 100084 清华大学电子工程系北京

It is presented the experiment of all optical demultiplexing of one 2.5 Gb/s channel from an 8×2.5 Gb/s OTDM data stream using nonlinear optical loop morror with 3 km dispersion shifted fiber. Bit error rate (BER) of the demultiplexed channel is measured. A BER of 10 -11 is achieved and the power penalty is only 1.4 dB when BER is 10 -9 .

关键词： optical time division multiplexing demultiplexing nonlinear optical loop mirror bit error rate

A NON LINEAR ANALYSIS OF TWO PHASE FLOW INSTA BILITY IN PARALLEL CHANNELS OF A BOILING SYSTEM

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Journal of Hydrodynamics 1999年第3期11卷 36-43页

作者： Zhou Yun long, Cheng Zhuo ming, Cai Hui Northeast China Institute of Electric Power Engineering, Jilin 132012, P.R.China (Received sep. 18, 1998)

This paper proposes a non linear mathematical model of two phase flow instability in parallel channels of a boiling system. Close agreement is obtained between calculations based on this model and measurements of the stable boundary in a system of two channels. The model is also applied to the cases of three and four parallel channels.

关键词： parallel channel flow instability mathematical model

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RESEARCH AND PROGRESS OF WEISFOGH MECHANISM HYDRODYNAMICS

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Journal of Hydrodynamics 1999年第3期11卷 55-60页

作者： Zhang She sheng, Wu Xiu heng, Wan Xian fu Department of Mathematics, Wuhan Transportation Univercity, Wuhan 430063, P.R.China (Received sep. 28, 1998)

Attention is focused on the research and progress of Weis Fogh mechanism hydrodynamics in this paper. We review some physical models and mathematical models of Weis Fogh mechanism, and also describe some analytic me... 详细信息

关键词： Weis Fogh mechanism hydrodynamics mathematical model

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Hydrogeophysical Parameters Estimation for Aquifer Characterisation in Hard Rock Environment: A Case Study from Yaounde, Cameroon

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Journal of Water Resource and Protection 2012年第11期4卷 944-953页

作者： William Assatsé Teikeu Philippe Nouck Njandjock Dieudonné Bisso Quentin Yene Atangana Jean-Paul sep Nlomgan Department of Earth Science University of Yaounde I Yaounde Cameroon Department of Physics Faculty of Science University of Yaounde I Yaounde Cameroon National Institute for Geologic and Mining Research Yaounde Cameroon

Detailed local geological and hydrogeophysical investigations were carried out for the aquifer in Yaoundé, Cameroon to delineate the architecture of different subsurface geological horizons using lithologs and generated vertical electrical sounding (VES) data. An attempt has also been made to estimate aquifer transmissivity from resistivity data. The transmissivity of the uncon?ned aquifer was computed by determining the Dar-Zarrouk parameters (longitudinal unit conductance and transverse unit resistance) and were compared with the actual field transmissivity. The results showed a direct relation between aquifer transmissivity and transverse resistance. The relationship established has therefore, been generalized in the study area in order to evaluate hydraulic conductivity and transmissivity at all the points where geoelectrical measurements have been carried out. This generalization allows one to derive maps of the product Kσ and transmissivity in the study area based on geoelectrical measurements. These maps are important in future modelling processes oriented towards better exploitation of the aquifers.

关键词： Hydrogeophysical Transmissivity Hydraulic Conductivity Yaounde

Validation of BESS （Balance Errors Scoring System） Test in Physical Education

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Journal of Sports Science 2017年第5期5卷 278-284页

作者： Claudia magaly Espinosa-Mendez Sebastian Leonardo San-Martin-Rodriguez Enrique R.P. Buendia-Lozada Rodrigo Ivan Aguilar Enriquez Department of Physical Culture Benemerita Universidad Autonoma de Puebla Puebla Puebla PC 72570 Mexico Department of Physical Education Ypsilanti College Puebla Puebla PC 72580 Mexico

The scoring system BESS （balance errors scoring system）, is a test commonly used by clinical investigators, however there is an increase of studies that couple the BESS system, as a measure of results beyond the scope of its original purpose introducing the field of sport, and in our case, as a possible assessment tool balance in physical education. In this paper, the application of BESS Test two different age groups, 5th-grade and 4 semester of high school, college Ypsilanti Puebla was conducted in order to validate it, using the Software ptets to analyze. It conducted a non-random selection of 26 elementary and 26 high school students, 13 men and 13 women in each case. The results were compared in 6 different positions, including 3 on a fiat surface and the other 3 on an implement with an unstable surface, each position must be maintained for 20 seconds. It was obtained as a result; the BESS Test is valid for children 5th-grade, not valid for high school students study.

关键词： BESS Test validation physical education.

Research on bird communities in fragmented high-Andean Polylepis woodland

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Research on bird communities in fragmented high-Andean Polyl...

Spectroscopic Properties of Yb3+ doped Borate Glasses

23rd International Ornithological Congress

作者： Jennifer Cahill Olga Ruíz Milton Fernández magaly Mercado Sebastian Herzog Susana Arrázola Erik Matthysen Centre of Biodiversity and Genetics. Universidad Mayor de San Simon Casilla 538 Cochabamba Bolivia Centre of Biodiversity and Genetics. Universidad Mayor de San Simon Casilla 538 Cochabamba Bolivia Centre of Biodiversity and Genetics. Universidad Mayor de San Simon Casilla 538 Cochabamba Bolivia Centre of Biodiversity and Genetics. Universidad Mayor de San Simon Casilla 538 Cochabamba Bolivia Centre of Biodiversity and Genetics. Universidad Mayor de San Simon Casilla 538 Cochabamba Bolivia Centre of Biodiversity and Genetics. Universidad Mayor de San Simon Casilla 538 Cochabamba Bolivia Dept. of Biology. Univ. of Antwerp. B-2610 Antwerpen. Belgium

＜正＞ High-Andean Polylepis woodlands form a unique ecosystem which extends up to 5000m altitude and supports a distinct avifauna with a large number of endemics. Yet, although the woodlands have become increasingly fragmented and disturbed, there have been virtually no detailed studies of the ecology of its bird specialists or the effects of habitat fragmentation and destruction on them. In 1999 we began collecting year-round data on

关键词： Andean avifauna Polylepis woodlands fragmentation ecology

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Chinese Journal of Lasers 1999年第4期B8卷 79-84页

作者： JIANG Chun ZHANG Junzhou HUANG Guosong GAN Fuxi (Shanghai Institute of Optics and Fine Mechanics, The Chinese Academy of Sciences, Shanghai 201800, China)Received sep. 7, 1998 Revised manuscript received Jan. 15, 1999 Shanghai Institute of Optics and Fine Mechanics The Chinese Academy of Sciences Shanghai 201800 China

The spectroscopic properties of Yb 3+ doped some borate glasses have been determined from absorption and emission measurements at room temperature. The emission cross sections range from approximately 1.0 to 1.7 pm 2. Systematic variations of the spectroscopic properties with glass composition and activator concentration can be used to optimize emission cross sections and fluorescence lifetimes.

关键词： Yb 3+ borate glasses spectroscopic property

Dynamics of Microbial Activity Related to N Cycling in Cd-Contaminated Soil During Growth of Soybean

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Pedosphere 2007年第3期17卷 383-388页

作者： YANG Ye CHEN Ying-Xu TIAN Guang-Ming ZHANG Zi-Jian Department of Environmental Engineering Zhejiang University Hangzhou 310029 （China） Appraisal Center for Environment and Engineering SEP Beijing 100012 （China）

The potential influences of cadmium (Cd) on the biochemical processes of the soil nitrogen (N) cycle, along with the dynamics of ammonification, nitrification, and denitrification processes in the rhizosphere and non-rhizosphere (bulk soil), respectively, were investigated in a Cd-stressed system during an entire soybean growing season. In terms of Cd pollution at the seedling stage, the ammonifying bacteria proved to be the most sensitive microorganisms, whereas the effects of Cd on denitrification were not obvious. Following the growth of soybeans, the influences of Cd on ammonification in the bulk soil were: toxic impacts at the seedling stage, stimulatory effects during the early flowering stage, and adaptation to the pollutant during the podding and ripening stages. Although nitrification and denitrification in the bulk soil decreased throughout the entire growth cycle, positive adaptation to Cd stress was observed during the ripening stage. Moreover, during the ripening stage, denitrification in the bulk soil under high Cd treatment (20 mg kg-1) was even higher than that in the control, indicating a probable change in the ecology of the denitrifying microbes in the Cd-stressed system. Changes in the activity of microbes in the rhizosphere following plant growth were similar to those in the non-rhizosphere in Cd treatments; however, the tendency of change in the rhizosphere seemed to be more moderate. This suggested that there was some mitigation of Cd stress in the rhizosphere.

关键词： cadmium microbial activity nitrogen cycle rhizosphere

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Barefoot and High-Heeled Gait: Changes in Muscles Activation Patterns

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Health 2014年第16期6卷 2190-2196页

作者： Nathalya Ingrid Cardoso do Nascimento Thaís sepêda Saraiva Alex Tadeu Viana da Cruz Jr. Givago da Silva Souza Bianca Callegari Institute of Health Sciences Federal University of Pará Belém Brazil Institute of Biological Sciences Federal University of Pará Belém Brazil Center for Tropical Medicine Federal University of Pará Belém Brazil

Most women like wearing high-heeled shoes for the benefit of sensuous attractiveness and self-esteem while musculoskeletal problems and gait patterns changes are often associated. The present study aimed to identify changes during the gait stance and swing phases in some lower limb muscles. In addition, abdominal muscle was included due to its importance in dynamic trunk stability, and lack of studies on the subject. Here, we found that the use of high-heeled shoes elicited not only the increasing of the electrical activity from the muscles involved in the gait cycle, but also altered the temporal sequence of their recruitment. As practical applications, these changes may be strategies to maintain stability and minimize risks of falling, but they are often associated to diseases. Women that use high-heeled shoes for prolonged time must apply specific muscle exercises to minimize its long-term effects.

关键词： Human Gait High-Heeled Shoes Lower Limb Muscles Temporal Activation Electromyography

Two-order Interference of Single Photon

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Chinese Journal of Lasers 2000年第5期9卷 81-85页

作者： JIANG Yunkun LI Jian SHI Baosen FAN Xiaofeng GUO Guangcan (Lab. of Quantum Communication & Quantum Computation, and Department of Physics University of Science & Technology of China, Hefei 230026) Received sep. 27, 1999 Revised manuscr 中国科学技术大学量子通信与量子计算开放实验室安徽合肥

A pair of photons called signal and idler photons, respectively, are produced through the nonlinear process of type I spontaneous parametric down conversion in BBO crystal pumped by the second harmonic wave of a Ti∶sapphire femtosecond laser pulse. The two order interference phenomenon of the signal photon in Michelson interferometer is observed and give an analysis in detail.

关键词： femtosecond pulses single photon Michelson interferometer