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Spatial Variability of Soil Organic Carbon in Different Hillslope Positions in Toshan Area, Golestan Province, Iran: Geostatistical Approaches

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Journal of Mountain Science 2015年第6期12卷 1422-1433页

作者： Abolfazl BAMERI Farhad KHORMALI Farshad KIANI Amir Ahmad DEHGHANI dept. of Soil Science Gorgan University of Agricultural Sciences and Natural Resources dept. of Water Engineering Gorgan University of Agricultural Sciences and Natural Resources

Accessibility to organic carbon(OC) budget is required for sustainable agricultural development and ecosystem preservation and restoration. Using geostatistical models to describe and demonstrate the spatial variability of soil organic carbon(SOC) will lead to a greater understanding of this dynamics. The aim of this paper is to present the relationships between the spatial variability of SOC and the topographic features by using geostatistical methods on a loess mountain-slope in Toshan region, Golestan Province, northern Iran. Hence, 234 soil samples were collected in a regular grid that covered different parts of the slope. The results showed that such factors as silt, clay, saturated moisture content, mean weighted diameter(MWD) and bulk density were all correlated to the OC content in different slope positions, and the spatial variability of SOC more to slope positions and elevations. The coefficient of variation(CV) indicated that the variability of SOC was moderate in different slope positions and for the mountain-slope as a whole. However, the higher variability of SOC(CV = 45.6%) was shown in the back-slope positions. Also, the ordinary cokriging method for clay as covariant gave better results in evaluating SOC for the whole slope with the RMSE value 0.2552 in comparison with the kriging and the inverse distance weighted(IDW) methods. The interpolation map of OC for the slope under investigation showed lowering SOC concentrations versus increasing elevation and slope gradient. The spatial correlation ratio was different between various slope positions and related to the topographic texture.

关键词： Geostatistics Loess Soil organic carbon(SOC) Slope position Spatial heterogeneity Topography

A GENERAL SOLUTION OF AXISYMMETRIC PROBLEM OF ARBITRARY THICK SPHERICAL SHELL AND SOLID SPHERE

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Applied Mathematics and Mechanics(English Edition) 1992年第6期13卷 515-521页

作者：卜小明严宗达 dept. of Mechanics Tianjin University Tianjin

In this paper, the axisymmetric problems of arbitrary thick spherical shell and solid sphere are studied directly from equilibrium equations of three-dimensional problem, and the general solutions informs of Legendre ... 详细信息

关键词： thick spherical shell solid sphere axisymmetric problems method of weighted residuals

Pointwise characterization for combinations of Szász-Mirakjan operators

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Applied Mathematics(A Journal of Chinese Universities) 2008年第2期23卷 202-212页

作者： XIE Lin-sen SHI Zhong-rui dept. of Math. Shanghai Univ. Shanghai 200444 China dept. of Math. Lishui Univ. Lishui 323000 China

The purpose of this paper is to characterize the pointwise rate of convergence for the combinations of Szász-Mirakjan operators using Ditzian-Totik modulus of smoothness.

关键词： Szász-Mirakjan operator combination pointwise approximation.

AN ANALYSIS OF THE LARGE DEFLECTION OF AN ELASTIC-PLASTIC CANTILEVER SUBJECTED TO AN INCLINED CONCENTRATED FORCE

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Applied Mathematics and Mechanics(English Edition) 1991年第6期12卷 547-555页

作者：栾丰余同希 dept. of Mechanics Peking University Beijing

Based on the Plastica theory (see ref. [12]), the large deflection of an elastic-perfectly plastic cantilever subjected to an inclined concentrated force at its tip, before the unloading in the plastic region occurs, is analyzed in this paper. The emphasis of the analysis is put on the effects of the angle of inclination of the concentrated force upon the deformed shape, the load-deflection relationship and the length of the plastic region. Both analytical and computed results are given.

关键词： Large deflection inclined concentrated force elastic-plastic cantilever Elastica Plastica

ISOLATION AND RECOGNITION OF PUTONGHUA VOICED INITIALS

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Chinese Journal of Acoustics 1988年第4期7卷 369-377页

作者：欧贵文 dept. of Computer Science of Zhongshan University

This paper discusses the acoustic characteristics of Putonghua voiced initials,the frequencycharacteristics of preemphasis and the important cue to discriminat voiced consonants from vowels:voicedconsonants are governed by low frequence signal while vowels by middle or high frequence *** algorithm for isolation and classification of initials based on the measurement of the energy ratio of thespeech signal with and without preemphasis was *** the experiment using all Putonghua syllableswith voiced initials spoken by a group of 8 adult speakers(4 males and 4 females)from different provinces ofChina,correct classification rate over 98% in grouping the initials into voiced initials and"zero"initials hadbeen *** also did an experiment for recognition of initials by applying stepwise linear discriminantanalysis and obtained average recognition rate of 86% for these initials.

关键词： ISOLATION AND RECOGNITION OF PUTONGHUA VOICED INITIALS

Periodic boundary value problem for the first order functional differential equations with impulses

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Applied Mathematics(A Journal of Chinese Universities) 2009年第1期24卷 27-35页

作者： LIANG Rui-xi SHEN Jian-hua dept. of Math. Hunan Normal Univ. Hunan 410081 China dept. of Math. Huaihua College Hunan 418008 China

This paper is concerned with the existence and approximation of solutions for a class of first order impulsive functional differential equations with periodic boundary value conditions. A new comparison result is pres... 详细信息

关键词： functional differential equation periodic boundary value problem lower and upper solution monotone iterative method

Molecular aspects of mammalian fertilization

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Asian Journal of Andrology 2001年第4期3卷 243-249页

作者： Hector Serrano Dolores Garcia-Suarez dept. Health Sciences Dept. Biology Universidad Autonoma Metropoliana-Iztapalapa Ave. Michoacan and Purisima Mexico City DF 09340 Mexico

Mammalian fertilization is a highly regulated process, much of which are not clearly understood. Here we presentsome information in order to elaborate a working hypothesis for this process, beginning with the sperm modifications inthe epidydimis up to sperm and egg plasmalemma interaction and fusion. We also discuss the still poorly understood ca-pacitation process, the phenomenon of sperm chemo-attraction that brings the capacitated sperm to interact with theoocyte vestments and certain aspects of the acrosome reaction. (Asian J Androl 2001 Dec; 3 : 243 - 249)

关键词： fertilization sperm maturation sperm capacitation sperm-ovum interactions membrane fusion

Study on autonomous satellite navigation from SHAR observations

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Journal of Harbin Institute of Technology(New Series) 2007年第5期14卷 662-667页

作者：黄琳荆武兴 dept. of Astronautics Harbin Institute of Technology

This paper uses two navigation schemes to prove the potential of a novel autonomous orbit determination with stellar horizon atmospheric refraction measurements. Scheme one needs a single processor and uses an extended Kalman filter. The second scheme needs two parallel processors. One processor uses a hatched leastsquare initial state estimator and a high-precision dynamic state propagator. The other processor uses a real-time orbit predictor. Simulations have been executed respectively for three types （low/medial/high） of satellite orbits on which various numbers of stars are observed. The results show both schemes can autonomously determine the orbits with a considerable performance. The second scheme in general performs a little better than the first scheme.

关键词： SHAR autonomous navigation extended Kalman filter batched least-square method artificial satellite

Error compensation on precision machine tool servo control system based on digital concave filter

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Journal of Harbin Institute of Technology(New Series) 2001年第4期8卷 389-393页

作者：王立松苏宝库张晶董申 dept. of Control Theory and Engineering Harbin Institute of Technology dept. of Computer Science and Engineering Harbin Institute of Technology dept. of Mechanical Engineering and Automation Harbin Institute of Technology

It is concluded from the results of testing the frequency characteristics of the sub micron precision machine tool servo control system, that the existence of several oscillating modalities is the main factor that affects the performance of the control system. To compensate for this effect,several concave filters are utilized in the system to improve the control accuracy. The feasibility of compensating for several oscillating modalities with a single concave filter is also studied. By applying a modified Butterworth concave filter to the practical system, the maximum stable state output error remains under ±10 nm in the closed loop positioning system.

关键词： precision machine tool concave filter oscillating modality