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PriChain: Efficient Privacy-preserving Finegrained Redactable Blockchains in Decentralized Settings

Chinese Journal of Electronics 2024年

作者： Hongchen GUO Weilin GAN Mingyang ZHAO Chuan ZHANG Tong WU Liehuang ZHU Jingfeng XUE School of Computer Science and Technology Beijing Institute of Technology School of Cyberspace Science and Technology Beijing Institute of Technology School of Computer and Communication Engineering University of Science and Technology Beijing

Recently, redactable blockchain has been proposed and leveraged in a wide range of real systems for its unique properties of decentralization, traceability, and transparency while ensuring controllable on-chain data redaction. However, the development of redactable blockchain is now obstructed by three limitations, which are data privacy breaches, high communication overhead, and low searching efficiency, respectively. In this paper, we propose PriC hain, the first efficient privacy-preserving fine-grained redactable blockchain in decentralized settings. PriChain provides data owners with rights to control who can read and redact on-chain data while maintaining downward compatibility, ensuring the one who can redact will be able to read. Specifically, inspired by the concept of multi-authority attribute-based encryption, we utilize the isomorphism of the access control tree, realizing fine-grained redaction mechanism, downward compatibility, and collusion resistance. With the newly designed structure, PriChain can realize O（n） communication and storage overhead compared to prior O（n2） schemes. Furthermore, we integrate multiple access trees into a tree-based dictionary, optimizing searching efficiency. Theoretical analysis proves that PriC hain is secure against the chosen-plaintext attack and has competitive complexity. The experimental evaluations show that PriChain realizes 10× efficiency improvement of searching and 100× lower communication and storage overhead on average compared with existing schemes.

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Numerical Simulation of Three-dimensional Heat and Mass Transfer in Spray Cooling of Converter Gas in a Venturi Scrubber

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Chinese Journal of Mechanical Engineering 2009年第5期22卷 745-754页

作者： LU Tao WANG Kuisheng School of Mechanical and Electrical Engineering Beijing University of Chemical Technology Beijing 100029 China

In order to predict the pressure drop, collection efficiency, velocity, temperature and mole fraction of vapor in an industrial venturi scrubber with water spraying for converter gas cooling, a three-dimensional model of heat and mass transfer with phase change is established. The gas flow and liquid droplets are treated as a continuous phase with a Eulerian approach and as a discrete phase with a Lagrangian approach, respectively. The coupled problem of heat, force, and mass transfers between gas flow and liquid droplets is solved by a commercial computational fluid dynamics（CFD） package, FLUENT. The numerical results show that the water injections have an important influence on the distributions of pressure, velocity, temperature, and mole fraction of vapor, especially for the spraying region in the throat. In the spraying region, the pressure drop is higher and the velocity is lower than in other regions due to the gas-droplet drag, while the temperature is lower because the droplet absorbs large amounts of heat from the high temperature gas and the mole fraction of vapor is higher due to the phase change of the liquid droplet. A number of cases with different Water-to-gas volume flow ratios and baffle openings were simulated. The dependence of pressure drop, velocity, temperature, mole fraction of vapor, and collection efficiency on both the water-to-gas volume flow ratio and baffle opening are analyzed. The good agreements between simulation results and experiment data of pressure drop, temperature, and collection efficiency validate the model. The model should facilitate optimization of the venturi scrubber design in order to give better performance with lower pressure drops and higher collection efficiency.

关键词： numerical simulation heat and mass transfer spray cooling converter gas venturi scrubber

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Large eddy simulation of hot and cold fluids mixing in a T-junction for predicting thermal fluctuations

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Applied Mathematics and Mechanics(English Edition) 2009年第11期30卷 1379-1392页

作者：朱维宇卢涛姜培学郭志军王奎升 School of Mechanical and Electrical Engineering Beijing University of Chemical Technology Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Thermal EngineeringTsinghua University

Temperature fluctuations in a mixing T-junction have been simulated on the FLUENT platform using the large eddy simulation （LES） turbulent flow model and a sub-grid scale Smagorinsky-Lilly model. The normalized mean and root mean square temperatures for describing time-averaged temperature and temperature fluctuation intensity, and the velocity are obtained. The power spectrum densities of temperature fluctuations, which are key parameters for thermal fatigue analysis and lifetime evaluation, are analyzed. Simulation results are consistent with experimental data published in the literature, showing that the LES is reliable. Several mixing processes under different conditions are simulated in order to analyze the effects of varying Reynolds number and Richardson number on the mixing course and thermal fluctuations.

关键词： numerical simulation thermal fluctuation T-junction mixing

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Effects of catalyst precursors on carbon nanowires by using ethanol catalytic combustion technique

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中国有色金属学会会刊：英文版 2006年第B1期16卷 385-387页

作者：程进邹小平李飞张红丹任鹏飞 Research Center for Sensor Technology Beijing Information Technology InstituteBeijing 100101China beijing Key Laboratory for Sensor Beijing 100101China

Iron nitrate, nickel nitrate and cobalt nitrate were used as catalyst precursors to study their effects on carbon nanowires synthesized by ethanol catalytic combustion (ECC) process. The as-grown carbon nanowires were characterized by means of scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that relatively uniform nanowires will be formed when the catalyst precursor is iron nitrate; while helical structure or disordered structure will be formed when the catalyst precursor is nickel nitrate or cobalt nitrate.

关键词：碳纳米线制备催化剂前驱物乙醇催化燃烧技术

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Electrical measurement on individual multi-walled carbon nanotubes

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中国有色金属学会会刊：英文版 2006年第B2期16卷 772-775页

作者：邹小平 H.ABE T.SHIMIZU A.ANDO H.OKUMOTO 朱申敏周豪慎 Research Center for Sensor Technology beijing Information Technology Institute Beijing 100101China beijing Key Laboratory for Sensor Beijing 100101 China Nanotechnology Research Institute National Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 HigashiTsukubaIbalaki 305-8562Japan Energy Electronics Research Institute National Institute of Advanced Industrial Science and Technology (AIST)1-1-1 UmezonoTsukubaIbalaki 305-8568Japan Energy Electronics Research InstituteNational Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 UmezonoTsukubaIbalaki 305-8568Japan Nanotechnology Research InstituteNational Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 HigashiTsukubaIbalaki 305-8562Japan Nano-electronics Research Institute National Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 Umezono Tsukuba Ibalaki 305-8568 Japan Nanotechnology Research Center Research Institute for Electronic ScienceHokkaido UniversitySapporo 001-0021Japan Energy Electronics Research InstituteNational Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 UmezonoTsukubaIbalaki 305-8568Japan Energy Electronics Research Institute National Institute of Advanced Industrial Science and Technology (AIST) 1-1-1 Umezono Tsukuba Ibalaki 305-8568Japan

The characterization of electrical property of multi-walled carbon nanotubes (MWCNTs) on a nanometer scale is essential for their potential application in nano-electronic devices. The MWCNTs were synthesized on Fe2O3/SiO2/Si substrate and Pt plate substrate by simple thermal chemical vapor deposition (STCVD) technique and the electrical measurements of individual MWCNT grown on silicon substrate and Pt plate substrate were performed by home-made 'nano-manipulator', respectively. According to current-voltage curves obtained in the experiments the current density that the MWCNTs can carry is calculated to be about 107 A/cm2, which is much larger than that of normal metals.

关键词：多壁碳纳米管电学测量简易热化学汽相沉积合成

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Preparation of carbon nanotubes by ethanol catalytic combustion technique using nickel salt as catalyst precursor

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中国有色金属学会会刊：英文版 2006年第B1期16卷 381-384页

作者：李飞邹小平程进张红丹任鹏飞 Research Center for Sensor Technology Beijing Information Technology InstituteBeijing 100101China beijing Key Laboratory for Sensor Beijing 100101China

A simple growth technique of carbon nanotubes (CNTs) by combustion of ethanol was developed. In the experiment, copper plate was employed as substrate, nickel nitrate (Ni(NO3)2) and nickel chloride (NiCl2) as catalyst precursor, and ethanol as carbon source. The cleaned copper substrate was dipped into catalyst precursor solution for mounting catalyst precursor particles. The dip-coated substrate was then placed into ethanol flame for about 10 min after drying. The black wool-like production grown on copper plate was obtained. This route is called an ethanol catalytic combustion(ECC) process. The black powders were characterized by means of scanning electron microscopy(SEM), transmission electron microscopy(TEM), energy dispersive X-ray spectrometer(EDS) and Raman spectroscopy. The results show that the techique is much simpler and more economical to meet the future broader applications.

关键词：碳纳米管制备催化剂前驱物乙醇催化燃烧技术硝酸镍

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Selective growth of carbon nanotube on silicon substrates

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中国有色金属学会会刊：英文版 2006年第B1期16卷 377-380页

作者：邹小平 H.ABE T.SHIMIZU A.ANDO H.TOKUMOTO 朱申敏周豪慎 Research Center for Sensor Technology Beijing Information Technology InstituteBeijing 100101China beijing Key Laboratory for Sensor Beijing 100101China Nanotechnology Research Institute National Institute of Advanced Industrial Science and Technology1-1-1 HigashiTsukubaIbalaki 305-8562Japan Energy Electronics Research Institute National Institute of Advanced Industrial Science and Technology1-1-1 UmezonoTsukubaIbalaki 305-8568Japan Nano-electronics Research Institute National Institute of Advanced Industrial Science and Technology1-1-1 UmezonoTsukubaIbalaki 305-8568Japan Nanotechnology Research Center Research Institute for Electronic ScienceHokkaido UniversitySapporo 001-0021Japan

The carbon nanotube (CNT) growth of iron oxide-deposited trench-patterns and the locally-ordered CNT arrays on silicon substrate were achieved by simple thermal chemical vapor deposition(STCVD) of ethanol vapor. The CNTs were uniformly synthesized with good selectivity on trench-patterned silicon substrates. This fabrication process is compatible with currently used semiconductor-processing technologies, and the carbon-nanotube fabrication process can be widely applied for the development of electronic devices using carbon-nanotube field emitters as cold cathodes and can revolutionize the area of field-emitting electronic devices. The site-selective growth of CNT from an iron oxide nanoparticle catalyst patterned were also achieved by drying-mediated self-assembly technique. The present method offers a simple and cost-effective method to grow carbon nanotubes with self-assembled patterns.

关键词： carbon nanotubes silicon substrate STCVD trench-patterned locally-ordered pattern

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Influence of Co Content on Raman and Photoluminescence Spectra of Co Doped ZnO Nanowires

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Journal of Materials Science & Technology 2012年第4期28卷 313-316页

作者： Y.Q. Chang P.W. Wang S.L. Ni Y. Long X.D. Li School of Materials Science anti Engineering University of Science and Technology Beijing Beijing 100083 China Department of Physics National Key Laboratory of Mesoscopic Physics Peking University Beijing 100871 China

Co doped ZnO nanowires with different Co contents have been fabricated by a chemical vapor deposition method. X-ray diffraction results show that all the samples are of single phase and crystallize in wurtzite ZnO structure. The lattice parameter a increases with increasing Co content, while the parameter c has no obvious change with increasing Co. Raman spectra show that the nonpolar E2（High） mode becomes broad and weak with the doping of Co, which indicates that the incorporation of Co causes structural disorder in the crystalline columnar ZnO lattice. The photolurninescence spectra exhibit that the position of the ultraviolet emission shifts to short wavelength and the intensity decreases with increasing Co. The green emission is affected by two contrary factors. It is increased by the introduced defects, but suppressed by the interaction between Co doping and native defects and the later affects it more significantly.

关键词： Co doped ZnO nanowires Raman Photoluminescence Single phase

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Effect of process conditions on the synthesis of carbon nanotubes by catalytic decomposition of methane

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China Particuology 2007年第3期5卷 213-219页

作者： Shuanglin Zhan Yajun Tian Yanbin Cui Hao Wu Yonggang Wang Shufeng Ye Yunfa Chen Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China Graduate University of Chinese Academy of Sciences Beijing 100049 China China University of Mining and Technology Beijing 100083 China

A new dual-composition catalyst based on Ni-Mo/MgO with high efficiency of producing carbon nanotubes （CNTs） from methane was reported recently. In the present article, with this type of catalyst, the impact of such experimental parameters as reaction temperature, reaction time, concentration of H2, flow rate ratio of CH4 to H2 on yield and graphitization were investigated, leading to the following optimal growth conditions： reaction time 60min, reaction temperature 900℃, CH4：H2 about 100：20mL/min, under which high-yield multi-walled CNTs bundles were synthesized. Raman measurement indicated that the as-synthesized product was well-graphitized, and the purity was estimated over 95% by TG-DSC analysis. In terms of the above results, an explanation of high-efficiency formation of CNTs bundles and the co-catalysis mechanism of Ni-Mo/MgO were suggested. 2007 Chinese Societv of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V.

关键词： Carbon nanotubes Catalytic decomposition Carbon yield Graphitization degree

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Noise helped manifestation of intrinsic frequency:A case study in the mesoscopic hormone signaling system

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Progress in Natural Science:Materials International 2009年第10期19卷 1209-1214页

作者： Lin Ji a,,Yuanyuan Zhang a,Xiufeng Lang b,Wenxiang Hu a,Qianshu Li c a Department of Chemistry,Capital Normal University,beijing 100048,China b School of Science,beijing University of Aeronautics and Astronautics,beijing 100191,China c The Institute for Chemical Physics,beijing Institute of Technology,beijing 100081,China Department of Chemistry Capital Normal University Beijing 100048 China School of Science Beijing University of Aeronautics and Astronautics Beijing 100191 China The Institute for Chemical Physics Beijing Institute of Technology Beijing 100081 China

The selective sustainment of nonlinear systems to signals is of great significance to signal transduction in living *** take hormone signaling as an example,and investigate the sustainment of internal and external *** results prove that signals with "intrinsic frequency",no matter if it is noise induced or external injected,can be selectively sustained by exploiting internal and/or external *** the internal and external noise can optimize the noise-induced signals,and the optimization is rather robust to the disturbance of external signals with other *** results are of significance for weak signal detection and transduction in the presence of external signals.

关键词： Noise Intrinsic frequency Mesoscopic system

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