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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 {2., Tsinghua university, Beijing 100084, china 2.Tsinghua National Laboratory for Information science and {2., Tsinghua university, department of Computer science and {2. Tsinghua University Beijing China Tsinghua National Laboratory for Information science and technology Tsinghua University Beijing 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

Fluorescent carbon dots synthesized in solid phase and air for application in LEDs

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Nano Research 2024年第9期17卷 8495-8503页

作者： Wei-Jie Zheng Zhao-Nan Sun Yi-ming Wang Huan-ming Xiong department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Fudan UniversityShanghai 200438China

Carbon dots(CDs)have been widely adopted as optical materials because of their excellent luminescent ***,most of the reported synthetic methods are conducted in solvents,especially hydrothermal/solvothermal reactions,leading to intractable problems such as toxic and flammable solvents,complex and inseparable by-products,and dangerously high pressures and ***-phase synthesis of CDs in air is an effective solution to overcome the above issues,but solid reactions always result in uncontrolled growth and agglomeration of *** this study,some inorganic salts are selected as catalysts for synthesizing CDs in solid states and air,which also play as dispersants to hinder CDs *** the meantime,some aromatic derivatives containing hydroxyl and amino groups are chosen as carbon sources,ground with the optimized catalyst,and then heated together in *** production yields are affected by the reaction time and reactant ratio,while the graphitization degrees of the CDs are determined by the reaction *** IG/ID value of their Raman spectra increases from 0.59 to 0.85,and the particle size decreases from 2.5 to 1.4 nm when the synthesis temperature is increased from 2.0 to 2.0℃.The as-prepared CDs show emission peaks ranging from 366 to 606 nm,with the photoluminescence(PL)quantum yield up to 53%.Their emission color variation mainly results from different carbon sources,which can be ascribed to the differences in the element composition,functional groups,and graphitic nitrogen content of these *** dispersing CDs of different concentrations into polyvinyl alcohol(PVA)and combining them with blue LEDs,cold,standard,and warm white light emitting devices(WLEDs)are prepared,with a color rendering index(CRI)up to *** the as-prepared CDs have antioxidant ability at high temperature,the as-prepared WLEDs have long lifespans,remaining the effective white luminescence after 72.h continuous work.

关键词： carbon dot solid-phase synthesis white LED photoluminescence inorganic salt catalysis

Protective effects of L-arginine on pulmonary oxidative stress and antioxidant defenses during exhaustive exercise in rats

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Acta Pharmacologica Sinica 2005年第8期26卷 992-999页

作者： Wan-teng LIN~(2.5), Suh-ching YANG~3, kung-tung CHEN~4, Chi-chang HUANG~3, Ning-yuean LEE~(2.6) ~2.department of Nutrition and Food {2.s, Fu-Jen Catholic university, Taipei, china ~3 School of Nutrition and Health {2.s, Taipei Medical university, Taipei, china ~4 department of General Education, ming Hsin university of {2. and {12. Hsinchu, china ~5 De Lin Institute of {12., Taipei, china department of Nutrition and Food sciences Fu-Jen Catholic University Taipei China De Lin Institute of technology Taipei China School of Nutrition and Health sciences Taipei Medical University Taipei China department of General Education Ming Hsin University of Science and Technology Hsinchu China

Aim: To assess the effects of L-arginine (L-Arg) supplementation on pulmonary oxidative stress and antioxidant defenses in rats after exhaustive exercise. Methods: Rats were randomly divided into four groups: sedentary control (SC), sedentary control with L-Arg treatment (SC+Arg), exhaustive exercise with control diet (E) and exhaustive exercise with L-Arg treatment (E+Arg). Rats in groups SC+Arg and E+Arg received a 2. L-Arg diet. Rats in groups E and E+Arg underwent an exhaustive running test on a motorized treadmill. Pulmonary oxidative stress indices [xanthine oxidase (XO), myeloperoxidase (MPO), and malondialdehyde (MDA)] and antioxidant defense systems [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), and glutathione (GSH)] were investigated in this study. Results: L-Arg supplementation significantly reduced exercise-induced elevations of XO and MPO activities in lung. LArg reversed the exercise-induced increase in SOD and GR activities, but increased CAT and GPX activities. L-Arg administration also significantly increased the GSH levels in plasma. Conclusion: L-Arg supplementation can prevent elevations of XO and MPO activities in the lung and favorably influence pulmonary antioxidant defense systems after exhaustive exercise.

关键词： L-arginine oxidative stress xanthine oxidase myeloperoxidase exhaustive exercise lung

Angular Multiplexing Storage in Azo-polymerLiquid Crystal Films Using Shearing Interferometer of Double-frequency Grating

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Chinese Journal of Lasers 2002年第2期11卷 43-46页

作者： ZHANG Jiangying ming Hai WANG Pei WU Yunxia XIE JianpingZHANG Qijin LIU Jiandepartment of Physics, department of Materials, university of science and technology of china , Hefei 2.002., china department of Physics University of Science and Technology of China Hefei 230026 department of Materials University of Science and Technology of China Hefei 230026

In this paper, the shearing interferometer of a double-frequency grating (DFG) and a small compact Nd: YVO4 double frequency laser at 532.nm are used to study the multiple storage in azo-polymer liquid crystal (PLC) films. In a principle experiment, the angle-encoded multiple gratings are recorded and the experimental results give triplex gratings at the same region in azo-PLC films, the angle between two adjacent grating vectors being 45°. Compared to the two-beam interferometer and four-wave mixing method, this method has simple configuration, high fringe contrast and quake-proof. A compatible angular multiplexing storage system in azo-PLC films is proposed.

关键词： shearing interferometer double-frequency grating angular multiplexing storage azo-polymer liquid crystal films

Investigation on UV-curing Reprocessable Thermosets Bearing Hindered Urea Bonds and Their Composites with Modified Zinc Oxide Nanoparticles

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Chinese Journal of Polymer science 2024年第6期42卷 751-765页

作者： Jun-Hao Zhou Li-ming Tang Key Laboratory of Advanced Materials of Ministry of Education of china Department of Chemical EngineeringTsinghua UniversityBeijing100084China

In this study,a series of hindered urea bond(HUB)containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the reactive diluent via one-pot *** prepolymers were characterized fully by various ***,their thermosets were fabricated via UV curing in presence of a photo initiator,and their mechanical property and thermal behavior were investigated and *** from the none HUB containing thermoset,the HUB containing thermosets(defined as PUT)could be recycled and reprocessed by hot press under relatively mild conditions with high recovery ratio of mechanical ***,zinc oxide(ZnO)nanoparticles were modified with 3-(trimethoxysilyl)propyl methacrylate and the modified ZnO(defined as ZnO-TPM)was dispersed and polymerized into PUT matrix to prepare their *** influence of ZnO-TPM on the mechanical performance of the composites was evaluated,which indicated that the Young’s modulus and tensile strength increased gradually to the maximum values at ZnO-TPM content of 1 wt%and then *** composites also displayed good reprocessability with improved recovery ratio compared to the pure PUT *** addition,the composite materials exhibited strong UV absorption capacity,implying their potential application in the circumstance where UV-shielding was required.

关键词： Polyurethane-urea methacrylate Hindered urea bond ZnO nanoparticles Reprocessing UV curing

INFLUENCE OF MOLECULAR WEIGHT OF CHITIN AND ITS THREE DERIVATIVES ON CRITICAL CONCENTRATION OF LYOTROPIC LIQUID CRYSTALLINE PHASE TRANSITION

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Chinese Journal of Polymer science 2000年第1期18卷 15-17页

作者： Yan-ming Dong Jian-wei Wang Qing Yuan department of Materials {2., Xiamen university, Xiamen 361005, china 厦门大学福建厦门

The critical concentration of lyotropic liquid crystalline phase transition for chitin derivatives was determined using a polarization microscope. The influence of molecular weight on critical concentration of liquid crystalline solution for chitin, chitosan, cyanoethyl chitosan and propionyl chitin successively increases as the chain rigidity decreases. Therefore it can be used as an indicator of the chain rigidity.

关键词： chitin chitosan lyotropic liquid crystalline polymer critical concentration molecular weight

Anthropogenic Impacts on the Sediment Flux in the Dry-hot Valleys of Southwest china—an Example of the Longchuan River

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Journal of Mountain science 2004年第3期1卷 239-249页

作者： ZHOUYue LUXixi HUANGYing ZHUYunmei FacultyofEnvironmentalscienceandEngineering KunmingUniversityofScienceandTechnologyKunming650093China departmentofGeography UniversityofSingapore10KentRidgeCrescent119260Singapore BureauofHydrologyandWaterResourcesofYunnanProvince Kunming650093China

The sediment flux data, measured from a dry-hot valley of the Longchuan River, a tributary of the lower Jinsha River, were analyzed with Mann-Kendall test, Seasonal Mann-Kendall test and Sen’s test. In both the upper reaches (Xiaohekou) and the lower reaches (Xiaohuangguayuan), the sediment fluxes showed a significant increase from 1970 to 2.01, despite the fact that the water discharge did not change significantly during the period and numerous reservoir constructions which contribute to the trap of sediment. This can be attributed to the intensification of human activities, especially the activities related to land surface disturbances such as deforestation and afforestation, expansion of agriculture land, and road constructions. This increase is more significant in the lower reaches of the river observed at the place of Xiaohuangguayuan due to the dry-hot climate. The profound increase in sediment flux has significant implications for effective management of the sedimentation problems of the on-going Three Gorges Reservoir.

关键词： Sediment flux dry-hot valley deforestation afforestation reservoir road construction

On Catastrophe and Cavitation for SphericalCavity

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Communications in Nonlinear science and Numerical Simulation 1999年第4期4卷 249-254页

作者： ming JIN Kefu HUANG Jike WU(department of Mechanics and Engineering {2., Peking university, Beijing 100871,china) department of Mechanics and Engineering science Peking University Beijing 100871 China

IntroductionInrecelltyears,theresearchesoncavitationandcatastropheofacavitysu***therwithbifllrcationtheory... 详细信息

IntroductionInrecelltyears,theresearchesoncavitationandcatastropheofacavitysu***therwithbifllrcationtheory...

关键词： nonlinearity bifurcation Hooke material

Advancement and prospect of short-term numerical climate prediction

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Chinese science Bulletin 2001年第18期46卷 1497-1502页

作者： CHOU Jifan & XU ming1. department of Atmospheric {2.s, Lanzhou university, Lanzhou 730000, china 2. Training Center of Chinese Meteorological Administration, Beijing 100081, china department of Atmospheric sciences Lanzhou University Lanzhou China Training Center of Chinese Meteorological Administration Beijing China

The defects of present methods of short-term numerical climate prediction are discussed in this paper, and four challenging problems are put forward. Considering our under developed computer conditions, we should innovate in the approcuch of numerical climate prediction on the basis of our own achievements and experiences in the field of short-term numerical climate prediction. It is possibly an effective way to settle the present defects of short-term numerical climate prediction.

关键词： short-term climate numerical prediction defects innovation.