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A new method of fabricating strained Silicon materials

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Rare Metals 2006年第z2期25卷 41-44页

作者： YANG Zongren LIANG Renrong XU Jun Institute of Microelectronics Tsinghua University Beijing 100084 China Institute of Microelectronics Tsinghua University Beijing 100084 China Microelectronics and Nanoelectronics Division of the Tsinghua National Lab for Information Science and Technology Beijing 100084 China Institute of Microelectronics Tsinghua University Beijing 100084 China

Strain-relaxed SiGe virtual substrates are of great importance for fabricating strained Si materials. Instead of using graded buffer method to obtain fully relaxed SiGe film, in this study a new method to obtain relaxed SiGe film and strained Si film with much thinner SiGe film was proposed. Almost fully relaxed thin SiGe buffer layer was obtained by Si/SiGe/Si multi-structure oxidation and the SiO2 layer removing before SiGe regrowth. Raman spectroscopy analysis indicates that the regrown SiGe film has a strain relaxation ratio of about 93% while the Si cap layer has a strain of 0.63%. AFM shows good surface roughness. This new method is proved to be a useful approach to fabricate thin relaxed epilayers and strain Si films.

关键词： strained Si SiGe oxidation strain relaxation

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Content-based information Processing-A New Challenge

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Content-based Information Processing-A New Challenge

第三十届中国控制会议

作者： ZHANG Bo information science & technology College,Computer science & technology Department, tsinghua national lab for information science & technology,State Key lab of Intelligent technology & Systems tsinghua University,Beijing 100084,P.R.China

＜正＞Since a big change of man-machine interaction mode has occurred in web era,information processing faces the *** is,information processing has had to deal with the semantic meaning of the *** information processing approaches only handle the form of information and are irrelevant to its semantic *** urgent affair is to establish a new strategy that can deal with the content of information based on the classical information processing *** the talk,the difficulty we faced recently and the future research direction in information processing are discussed,expressly;the multi-disciplinary study among neural science,cognitive science,psychology and information science is emphasized.

关键词： information processing Semantics Multi-disciplinary study

Design of a Printed MonopoLe Antenna for Dualband WLAN Application Using PSO

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Design of a Printed MonopoLe Antenna for Dualband WLAN Appli...

2006 7th International Symposium on Antennas, Propagation and EM Theory

作者： Zhengyi Li and Ke Gong tsinghua national lab for information science & technology, Department of Electronic Engineering, tsinghua University, Beijing 100084, China

Recently, a novel evolutionary optimization algorithm, Particle Swarm Optimization (PSO), has been successfully applied to a large variety of fields. In this paper, a printed monopole antenna for dualband WLAN is designed by using PSO. It is shown that the antenna can be quickly designed to meet the requirements for dualband WLAN application

关键词： Design of a Printed MonopoLe Antenna for Dualband WLAN Application Using PSO

Enhance Aggregate Throughput in Multi-radio Wireless Mesh Network

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Enhance Aggregate Throughput in Multi-radio Wireless Mesh Ne...

IEEE 2007 International Symposium on Microwave,Antenna,Propagation and EMC Technologies for Wireless Communications(ISMAPE-2007)

作者： Hao ZHANG Xiaofeng ZHONG Yun XU tsinghua national lab for information science and technology Beijing(100084),P.R.CHINA

Multi-radio and power control have been introduced into enhancing aggregate throughput of wireless mesh network(WMN).An actual test bed is built in this paper to examine how these two factors influence aggregate throughput of *** results show that multi-radio approach is better in multi-hop scenario than that with single ***,a dynamic power control algorithm can enhance performance of WMN especially in multi-hop scenario too.

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Connector Optimization in Virtual Backbone Network

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Connector Optimization in Virtual Backbone Network

IEEE 2007 International Symposium on Microwave,Antenna,Propagation and EMC Technologies for Wireless Communications(ISMAPE-2007)

作者： Hao ZHANG Xiaofeng ZHONG Jing WANG tsinghua national lab for information science and technology Beijing(100084),P.R.CHINA

Connected dominating set(CDS) has been proposed as virtual backbone or spine of wireless ad hoc *** this paper,we propose a new algorithm optimizing connector number in *** algorithm tightens upper bound of Connector/Dominator to 3:1,compared with original *** though the new algorithm needs some extra information,its time and message complexity does not *** addition,the new algorithm still keeps important properties in[5]but with less interference when applied to multi-radio scenario.

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An introduction to tsinghua Cloud

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science China(information sciences) 2010年第7期53卷 1481-1486页

作者： ZHENG WeiMin1,2 1Department of Computer science and technology, tsinghua University, Beijing 100084, China 2tsinghua national laboratory for information science and technology, Beijing 100084, China 1. Department of Computer science and technology Tsinghua University Beijing 100084 China2. Tsinghua National Laboratory for Information Science and Technology Beijing 100084 China

Cloud computing has become a trend that draws attention from both academia and industry all over the world. This paper unveils details of tsinghua Cloud, a comprehensive solution for cloud computing developed by Tsing... 详细信息

关键词： cloud computing distributed file system virtual computing environment data sharing

Learning interactions among multi-channel sequences with dynamical influence models

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science China(information sciences) 2010年第7期53卷 1336-1344页

作者： ZHANG WeiDong, CHEN Feng & XU WenLi Department of Automation, national laboratory for information science and technology, tsinghua University, Beijing 100084, China 1. Department of Automation National Laboratory for Information Science and Technology Tsinghua University Beijing 100084 China

Many real applications involve simultaneous recording and analysis of multi-channel information sources. Learning and modeling the interactions among channels is the kernel step to analyze and recognize system characteristics. This paper presents a model that learns the dynamical influence among multi-channel sequences. The model, dynamical influence model, permits functional roles of individual channels to change and models the changing influence strength between channels. By querying the values of influence factors, we can recognize the functional role of each channel qualitatively and learn about to what extent the chains influence each other quantitatively at any time. The experimental results on synthetic data and application of multi-person interaction recognition show that our model is reliable and effective.

关键词： multi-channel processing dynamical interaction influence model activity recognition

Detection and formation mechanism of micro-defects in ultrafine pitch Cu-Cu direct bonding

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Chinese Physics B 2016年第1期25卷 802-808页

作者：刘子玉蔡坚王谦陈瑜 Institute of Microelectronics Tsinghua UniversityBeijing 100084China tsinghua national laboratory for information science and technology Beijing 100084China

In this paper, Cu-Cu interconnects with ultrafine pad pitches of 6 p.m, 8 p.m, and 15 p.m are implemented on the 12 inch wafers by a direct bonding process. Defects are not found by traditional non-destructive （NDT） c-mode scanning acoustic microscopy （c-SAM）. However, cross sectional observation of bonding interfaces reveals that micro-defects such as micro seams are located at SiO2 bonding interfaces. In order to examine the micro-defects in the ultra-fine pitch direct bonding process by the NDT technology, a novel ＂defect-enlarged approach＂ is proposed. The bonded dies are first annealed in an N2 oven at 300 ℃ for a few hours and then cooled quickly in air. The c-SAM scanning images show large defects at the place where nothing can be detected by c-SAM before this treatment. Cross sectional observation of the bonding interfaces indicates that these defects consist of large size micro seams at the SiO2 bonding interface, especially near Cu pads with an ultrafine pitch of 6μm. However, these large defects disappear after several hours at room temperature, observed by c-SAM. It is inferred that the disappearance of these defects inspected by the ＂defect-enlarged approach＂ results from the combination of intrinsic micro seams and ＂weak＂ bonds in the silicon oxide layer. Then the underlying physical mechanism of these micro-defects is proposed, which is influenced by Cu pad surface topology and bonding models.

关键词： nondestructive testing of materials microscopy acoustical surface and interface

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Corslet: A shared storage system keeping your data private

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science China(information sciences) 2011年第6期54卷 1119-1128页

作者： XUE Wei 1,2 , SHU JiWu 1,2 , LIU Yang 1 & XUE Mao 1 1 Department of Computer science and technology, tsinghua University, Beijing 100084, China 2 tsinghua national laboratory for information science and technology, tsinghua University, 1. Department of Computer science and technology Tsinghua University Beijing 100084 China2. Tsinghua National Laboratory for Information Science and Technology Tsinghua University Beijing 100084 China

With the exponential growth of digital data, it is becoming more and more popular to store data in shared distributed storage systems inside the same organization. In such shared distributed storage systems, an ordinary user usually does not have the control permission over the whole system, and thus cannot secure data storage or data sharing of his own files. To solve this issue, this paper proposes a new system architecture to secure file storing and sharing efficiently over untrusted shared storage and network environments. Based on this architecture, this paper designs and implements a stackable secure storage system called Corslet. Corslet can run directly on deployed underlying storage systems without modification, while bringing end-to-end confidentiality and integrity as well as efficient access control for user data. For individual users, Corslet is easy to use, and does not require users to maintain or manage any keys on their client machines locally. The Bonnie++ and IOzone benchmark results show that the throughput of Corslet over NFS can achieve more than 90% of native NFS throughput in most tests, proving that Corslet can provide enhanced security for user data while maintaining acceptable performance.

关键词： storage security access control key management shared file system