水文土壤学理论及其应用研究进展

围绕水文土壤学的基本理论和核心科学问题,从地球关键区理论出发,介绍了水文土壤学的基本理论框架、水文土壤学所能填补的知识鸿沟,并回顾了水文土壤学在农业、流域管理、面源污染、湿地保护和环境政策制定以及土壤传递函数等方面的应用,最后对水文土壤学的发展和应用做了展望。     

基于HOG及在线多实例学习的目标跟踪算法

传统的基于色彩直方图或空间色彩直方图的跟踪算法在跟踪目标出现尺度变化的复杂条件下,因无法显著区分颜色相近的目标和背景,不能得到准确跟踪结果.提出基于HOG及在线多实例学习的目标跟踪算法.此算法采用HOG特征值提取方式,结合在线多实例学习技术,对目标远离场景、平移、旋转、遮挡等情况进行跟踪.实验结果表明,该算法能够对各种复杂情况下的动态目标进行有效跟踪,具有良好的鲁棒性和准确性.     

Interactions between hotspots and the Southwest Indian Ridge during the last 90 Ma:Implications on the formation of oceanic plateaus and intra-plate seamounts

This study investigates the relationship between the hotspot-ridge interaction and the formation of oceanic plateaus and seamounts in the Southwest Indian Ocean.We first calculated the relative distance between the Southwest Indian Ridge (SWIR) and relevant hotspots on the basis of models of plate reconstruction,and then calculated the corresponding excess magmatic anomalies of the hotspots on the basis of residual bathymetry and Airy isostasy.The results reveal that the activities of the Marion hotspot can...     

The Effects of Microstructure on the Tensile and Impact Properties of A 1.0% V, 0.2% C Steel

Abstract

This paper investigates the effects of various heat treatments on the microstructure and mechanical properties of a 1% V, 0.2 % C steel. This precipitation hardening steel was submitted to selective heat treatments, in order to produce a range of austenitic and ferritic grain sizes and structures.

The limitations of high austenitizing temperatures are examined, and the heat treatment which led to good mechanical properties are discussed in relation to microstructural features.

Résumé

Cet article traite des effets de divers traitements thermiques sur la microstructure et les propriétés mecaniques d'un acier 1% V, 0.2 % C. Cet acier, durci par précipitation, a été soumis à divers traitements thermiques sélectifs, de manière à produire des grains de dimensions et de structures austenitique et ferrique variées.

Les limitations dues à des températures élevées d'austénitisation ont été examinées, et le traitement thermique conduisant à de bonnes propriétés mécaniques sont discutés en relation avec les caractéristiques microstructurales.     

Study on the fluid/structure interaction at different inlet pressures in molded packaging

This paper presents the computational study of fluid/structure interaction (FSI) analysis in the molding process using the Mesh-based parallel Code Coupling Interface (MpCCI) method with finite volume coding (FLUENT 6.3) and finite element coding (ABAQUS 6.9). The FSI analysis is implemented on the molded package during the encapsulation process with different inlet pressures. Real-time flow visualization, deformation and stress of the silicon die during the encapsulation process are presented in this paper. A fluctuation phenomenon of the silicon die is found in the encapsulation process when the inlet pressure increases. The maximum deformation during the process is determined at different locations on the silicon die, calculated during the final stage of the filling process. The deformation and stress of the die is exponentially increased with increasing inlet pressure. The maximum stress on the solder bump is concentrated near to the inlet gate. Thus, the present FSI analysis approach is expected to be a guideline or reference and provides better understanding of the encapsulation process for package design in the microelectronic industry.     

The dimensional nature of same–different discrimination behavior in pigeons.

We studied the dimensional nature of same–different discrimination behavior in pigeons. Birds first learned to discriminate between simultaneously presented displays of 16 identical items (Same arrays) and 16 nonidentical items (Different arrays), conditional on the color of the background. After discrimination mastery, we tested the birds with Mixture arrays comprising both identical and nonidentical items. Accuracy increased and reaction time decreased as the disparity in entropy (a measure of variability) between the arrays increased. As well, within each entropy disparity level, lower entropy values were more discriminable than higher entropy values. These results accord with a logarithmic relation between entropy and discriminative behavior and, thus, with the idea that the discrimination of Same from Different arrays follows Weber's Law. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Heterotactic Enthalpic Interactions of L-Arginine with 2,2,2-Trifluoroethanoi in Aqueous Solutions at 298.15,303.15 and 310.15 K

The enthalpies of mixing of L-arginine with 2,2,2-trifluoroethanol and their respective enthalpies of dilution in aqueous solutions at 298.15,303.15 and 310.15 K were determined as a function of the mole fraction by flow microcalorimetric measurement.These experimental results were analyzed to obtain heterotactic enthalpic interaction coefficients(hxy,hxxy,hxyy)according to the McMillan-Mayer theory.The hxy coefficients between L-arginine molecule studied and 2,2,2-trifluoroethanol molecule in aqueous solutions at 298.15,303.15 and 310.15 K were found to be all negative.The results were discussed in terms of solute-solute interaction and solute-solvent interaction.     

Kohn anomaly in graphene

Symmetry based analysis of the Kohn anomaly is performed. Kohn phonon frequencies and displacements are calculated by force constant method. It is shown that Kohn phonon vibrations cause electronic band gap opening.