The Challenging Topics and Future Directions of the Research in Limnology and Watershed Sciences

Based on reviewing the problems in limnology and watershed sciences in meeting the national demands and the development of theories and methodology, this paper proposed some challenging topics to the sciences, covering the process of lake evolution and the quantitative analysis of human impacts, in -lake nutrient cycling an biogeo-chemical process, the process and mechanisms of material flow in lake-watershed system, digital watershed and the modeling of the surface process of lake -watershed, and ecosystem health and scientific management of lake-watershed.     

Shear-wave splitting and anisotropy in crust of Dabieshan orogenic belt

The shear-wave splitting was analyzed on the deep seismic sounding profile crossing the Dabieshan area. The direction difference between Sg and SmS fast wave polarization indicates that the modem regional tectonic stress field in the Dabieshan area exists only in uppcr crust, while the crack alignment caused by the Triassic collision between the North China and the Yangtze blocks had been preserved in mid-lower curst.     

A hybrid Jacobian control for uncalibrated robot visual servoing

This paper focuses on the visual servo control of an uncalibrated robotic arm with an eye-in-hand camera. Without a prior knowledge of the kinematics of the robotic arm or camera calibration, the proposed hybrid Jacobian controller can track a moving object using visual feedback and joint-space velocity feedback. The proposed hybrid control method is a combination of the uncalibrated visual servoing and approximate Jacobian feedback control. First, the Jacobian matrix from joint-space to image-space is estimated by recursive least-squares (RLS) algorithm, and then the approximate Jacobian feedback controller is designed by using visual feedback and joint-space velocity feedback. The performances of the proposed control methods are illustrated by computer simulations.     

Research on system-of-systems combat simulation model formal specification and representation

1. INTRODUCTION Weapon equipments acquisition and demonstration has become more and more prominent in the informationalized war conditions while operational effectiveness evaluation is its core part. The compl- exity and uncertainty of weapon systems operational effectiveness evaluation make traditional analysis methods or expert evaluation methods less effective to solve problems. Simulation based operational effe- ctiveness evaluation is an efficient solution. The increased complexity o…     

Seasonal variation of snow microbial community structure in the East Rongbuk glacier, Mt. Everest

Mt. Everest, the zenith of the world, plays an impor- tant role in the global climate change. During the lastdecade, some studies on glacier and snow have been undertaken in this region. The climate and environment changes in the past hundred years have b…     

自然科学领域著名期刊简介-Cell及其姊妹刊

Cell创刊于 1976年 ,现已成为世界自然科学研究领域最著名的期刊之一 ,并陆续发行了 8种姊妹刊 ,在各自专业领域里均占据着举足轻重的地位。Cell以发表具有重要意义的原创性科研报告为主 ,许多生命科学领域最重要的发现都发表在Cell上。本文旨在介绍该刊及其姊妹刊的办刊宗旨、征稿要求及评审程序 ,以使我国科学家能更加了解Cell系列期刊 ,提高投稿率和录用率 ,把出色的科研成果展示给世界 ;同时也能够通过阅读Cell系列期刊 ,把握世界最前沿的科学研究动向 ,加强我国与世界科学界的联系。     

英国动物性食品安全研究现状及我国优先发展领域

本文介绍了英国等欧盟国家的动物性食品安全研究现状;探讨了我国目前在动物性食品安全研究中存在的问题;并从残留代谢组学、营养基因组学、动物性食品功能基因组学、动物性食品病原微生物、疯牛病检测技术及动物源食品安全相关的环境生态学研究等方面,提出了我国动物性食品安全的优先研究领域。     

移相控制双全桥电力电子变压器的稳态特性

分析了移相控制双全桥电力电子变压器的工作原理，通过系统状态空间模型分析，得到了等效变压器模型及其外特性曲线，给出了该模型的等效变比及等效内阻的表达式，从模型本质上证明了电力电子变压器对于传统工频变压器的在系统功能上的可替代性和可扩展性，最后通过仿真实验验证了理论分析的正确性。     

适于数模混合集成电路的可布性分析模型

布局、布线是集成电路后端物理设计的两个主要环节,可布性分析作为连接布局和布线的枢纽,对优化布局和提高布线的布通率具有非常重要的作用。作者提出一种不可切割(non-slicing)结构的非均匀划分算法,大幅度减少了划分后的区域数量,同时建立了与此相应的适用于数模混合集成电路布局的可布性分析模型。对于实验电路的分析证实了本模型的准确性和高效性。     

参考安全补丁比对的软件安全漏洞挖掘方法

Windows操作系统作为目前全球使用最广泛的桌面操作系统,一旦其漏洞被利用将造成严重后果,所以对Windows操作系统的漏洞发掘意义重大。当前对软件安全漏洞的发现更多的是依靠安全研究人员的经验和运气,缺乏系统且有效的方法指导。为了找到一种能够快速发现Windows一类漏洞的方法,本文从安全补丁的修补方法入手,分析了漏...