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Kinetic contribution of CO_2/O_2 additive in methane conversion activated by non-equilibrium plasmas

Chinese Journal of Chemical Engineering 2018年第5期26卷 1041-1050页

作者： Qi Chen Jintao Sun xiaojun zhang School of Mechanical and Electronic Control Engineering Beijing Jiaotong University

A temperature-controlled and pressure-controlled coaxial dielectric barrier discharge （DBD） reactor was developed to decouple the thermal and kinetic effects of radio frequency （RF） discharge on methane conversion, and further to compare the kinetic behaviors of the mechanistically similar reactions of methane conversion with O2 and CO2 additives. A kinetic mechanism for RF plasma assisted methane conversion was assembled. The formation of products in the RF plasma reactor was measured with Gas Chromatography （GC-TCD） and the data were used to validate the kinetic model. The experimental and computational results showed the different kinetic roles of carbon dioxide and oxygen additives in methane conversion, due to the different dissociation and ionization energy of the two additive gases, as well as the thus produced electron energy distribution function （EEDF）. Fuel oxidation by plasma generated O, O（1D）, O2（a1△Ag）, O2（b1∑＋g） and O＋ in partial oxidation of methane was observed essential for methane consumption, which resulted in an increase in methane conversion rate, compared to pure methane pyrolysis and dry reforming of methane with CO2 additive. It was also found that dry reforming of methane with CO2 was by far the easier to produce the syngas as well as C2 hydrocarbon species, due to the weak oxidation ability of CO2 and also the significant deposition of the electron energy on CH4 disso- ciation in a dry reforming discharge mixture. This kinetic study produced comparative data to demonstrate the contribution of CO2/O2 additive in non-eauilibrium plasma assisted methane conversion.

关键词： RF plasma Plasma assisted combustion Methane conversion Sensitivity analysis Reaction kinetics

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Diversity of 16S rDNA and environmental factor influ-encing microorganisms in Malan ice core

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Chinese Science Bulletin 2003年第11期48卷 1146-1151页

作者： zhang xiaojun MA xiaojun YAO Tandong zhang Gaosen Cold and Arid Regions Environmental Engineering Research Institute Chinese Academy of SciencesSchool of Life Science Lanzhou UniversityCold and Arid Regions Environmental Engineering Research Institute Chinese Academy of SciencesSchool of Life Science Lanzhou University Lanzhou 730000 ChinaLanzhou 730000 ChinaLanzhou 730000 ChinaLanzhou 730000 China

The research on extrempholic microorganisms in glacial low-temperature environment receives more attention than ever before. Due to the successive chronological records in ice core, it is important to initiate microbiological studies on ice core samples. 23 samples from one ice core, drilled from central Qinghai-Tibetan Plateau, were analyzed. The number of total microorganisms and culturable microorganisms in different layers showed that it related with the content of dust in ice. It is suggested that the distribution of microorganisms in ice depends on the transportation of materials during glacier development. The bacteria diversity in Malan Glacier was analyzed by 16S rDNA sequencing methods, which showed that many sequences were similar to known psychrophilic bacteria.

关键词：微生物青藏高原 rDNA 喜寒细菌低温环境冰冻层

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Communication between osteoblasts stimulated by electromagnetic fields

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Chinese Science Bulletin 2007年第1期52卷 98-100页

作者： zhang JianBao zhang xiaojun The Key Laboratory of Biomedical Information Engineering of Ministry of Education Institute of Biomedical Engineering Xi'an Jiaotong University Xi'an 710049 China Department of Physics Fourth Military Medical University Xi'an 710032 China

Pulsed electromagnetic field can affect the proliferation of osteoblasts, but the mechanism is obscure yet. The communication between osteoblasts, isolated from calvaria bone of newborn SD rats and stimulated with the rectangular electromagnetic field of 15 Hz and 4 mT, was studied. Our results showed that the osteoblasts radiated a kind of light after they were stimulated with the electromagnetic field and it is the light that promotes the proliferation of un-stimulated osteoblasts.

关键词：造骨细胞电磁疗法信息交流细胞结构

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Highly cycle-stable VOPO_(4)-based cathodes for magnesium ion batteries:Insight into the role of interlayer engineering in batteries performance

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Nano Research 2024年第7期17卷 6127-6138页

作者： Jiahe zhang Jing Shang xiaojun zhang Ke Wang Yihe zhang Engineering Research Center of Ministry of Education for Geological Carbon Storage and Low Carbon Utilization of Resources Beijing Key Laboratory of Materials Utilization of Nonmetallic Minerals and Solid WastesNational Laboratory of Mineral MaterialsSchool of Materials Science and TechnologyChina University of Geosciences(Beijing)Beijing 100083China

It is the sluggish ion migration kinetics that seriously affects the practical performance of the magnesium ion *** though an electrode material design using rational interlayer engineering method could effectively solve this issue,the optimal interlayer distance remains ***,various VOPO_(4)-based electrodes with expanded interlayer spacing were fabricated and the relationship between interlayer structure and battery performance was *** analysis combined with computations unveils the existence of an optimal interlayer structure,as inadequate expansion failed to fully utilization of the material performance,while excessive expansion degraded the electrode *** them,the electrode with triethylene glycol(TEG)intercalation exhibited optimized performance,maintaining excellent cycling stability(191.3 mAh·g^(−1)after 800 cycles).Density functional theory(DFT)demonstrated the effectiveness and limitations to lowering the migration energy barrier by expanding the interlayer *** addition,systematic mechanism research revealed the Mg^(2+)storage process:The stepwise shuttling of Mg^(2+)along the directions that lie in(001)plane triggers two pairs of redox processes,namely V^(5+)/V^(4+)and V^(4+)/V^(3+).This study,regulation of layer spacing to achieve the best integrated performance of electrodes,could deepen the understanding of interlayer engineering and guide the design of advanced multivalent-ion batteries.

关键词： magnesium ion batteries layered electrodes interlayer engineering energy storage mechanisms high kinetics

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PARALLEL COMPUTING FOR STATIC RESPONSE ANALYSIS OF STRUCTURES WITH UNCERTAIN-BUT-BOUNDED PARAMETERS

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Acta Mechanica Solida Sinica 2008年第5期21卷 472-482页

作者： Zhiping Qiu xiaojun Wang Xu zhang Institute of Solid Mechanics Beijing University of Aeronautics and Astronautics Beijing 100083 China

The vertex solution for estimation on the static displacement bounds of structures with uncertain-but-bounded parameters is studied in this paper. For the linear static problem, when there are uncertain interval parameters in the stiffness matrix and the vector of applied forces, the static response may be an interval. Based on the interval operations, the interval solution obtained by the vertex solution is more accurate and more credible than other methods （such as the perturbation method）. However, the vertex solution method by traditional serial computing usually needs large computational efforts, especially for large structures. In order to avoid its disadvantages of large calculation and much runtime, its parallel computing which can be used in large-scale computing is presented in this paper. Two kinds of parallel computing algorithms are proposed based on the vertex solution. The parallel computing will solve many interval problems which cannot be resolved by traditional interval analysis methods.

关键词： vertex solution interval analysis UBB parallel computing

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Insecurity of a Public Proof of Cloud Storage from Lattice Assumption

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Chinese Journal of Electronics 2017年第1期26卷 88-92页

作者： zhang xiaojun XU Chunxiang zhang Yuan zhang Xiujie WEN Junwei School of Computer Science and Engineering University of Electronic Science and Technology of China School of Computer Science Southwest Petroleum University School of Computer Engineering Weifang University

Cloud storage auditing is considered as a significant service to verify the integrity of the data stored in cloud. Liu et al. have proposed a proof of storage protocol with public auditing form lattice assumption, which can resist quantum computer attacks. They claim that the protocol enjoys desirable security properties, such as unforgeability and privacy preserving. We demonstrate that any malicious cloud service provider can cheat the third party auditor and the users, through generating the valid response proof which can pass the verification even if some other data blocks are lost by accident. And the primitive data blocks maybe recovered by any curious third party auditor through solving some linearly equations. Our work can help cryptographers and engineers design and implement more secure and efficient lattice-based public auditing scheme for the cloud storage data.

关键词： Cloud storage Public auditing Lattice assumption Quantum computer attacks

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Water-induced luminescence improvement in a lanthanide β-diketone complex for monitoring water purity

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Chinese Chemical Letters 2022年第4期33卷 2117-2120页

作者： xiaojun zhang Xiaomeng Jin Yuxin Li Key Laboratory of Function Inorganic Material Chemistry(MOE) School of Chemistry and Material ScienceHeilongjiang UniversityHarbin 150080China

Water-caused luminescence quenching is a well-known and intractable issue for luminescence lanthanide complexes, greatly confining their broad application as sensing and displaying devices in water ***, an anionic and coordination-saturated lanthanide complex with a nanosheet-like structure has been prepared. It exhibits excellent photophysical properties both in solid state and in aqueous suspension. Noteworthily, a 13% improvement for sensitization efficiency from organic ligand to central lanthanide ion has been realized, indicating an exceptional phenomenon of water-induced luminescence improvement which is rarely reported previously. Moreover, the aqueous suspension of as-prepared luminophore could act as a chemo-sensor responding to various organic solvents in water. Both of waterinduced luminescence improvement and extended sensing behavior in this work provide a new platform for developing highly performant and practical luminescent materials in the water system.

关键词： Water-induced luminescence improvement Lanthanide complex β-Diketone ligand Water quality monitor Luminescence sensing Through-space charge transfer

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Sphalerite Rb-Sr Dating and in situ Sulfur Isotope Analysis of the Daliangzi Lead-Zinc Deposit in Sichuan Province, SW China

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Journal of Earth Science 2018年第3期29卷 573-586页

作者： Wenhao Liu xiaojun zhang Jun zhang Manrong Jiang Faculty of Earth Resources China University of Geosciences Institute of Geological Survey China University of Geosciences

This study reports the sphalerite Rb-Sr age and LA-MC-ICP-MS in situ sulfur isotope analysis results of the Daliangzi Lead-Zinc Deposit in the Sichuan-Yunnan-Guizhou （SYG） triangle. Sphalerite Rb-Sr dating yields a Mississippian age of 345.2±3.6 Ma （MSWD=I.4）, which is older than the published Late Triassic mineralization ages （230-200 Ma） of some other deposits. This indicates that at least two stages of lead-zinc mineralization have occurred in the SYG lead-zinc triangle. The first stage occurred in the Mississippian under an extensional environment, while the second stage occurred in the Late Triassic under a compressional environment. In situ sulfur isotope analysis of sphalerite growth zoning presents relatively large δ^34S values of 11.3‰-15.2‰ with small variations. The large δ^34S values indicate a reduced sulfur source of thermochemical reduction of seawater sulfates. Abundant organic matter in the black fracture zone possibly supplied reductants for thermochemical sulfate reduction （TSR） at the mineralization site. The small variation of δ^34S values suggests a slow and stable TSR process that could prevent the sudden supersaturation of sphalerite in the fluid and the resulting of fast participation. This is consistent with the well-crystallized characteristic of the sphalerite of the Daliangzi Deposit.

关键词： sphalerite Rb-Sr in situ sulfur isotope thermochemical reduction Daliangzi Mississippi Valley-type.

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Designated Cloud Server Public Key Encryption with Keyword Search from Lattice in the Standard Model

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Chinese Journal of Electronics 2018年第2期27卷 304-309页

作者： zhang xiaojun XU Chunxiang XIE Run JIN Chunhua School of Computer Science Southwest Petroleum University School of Computer Science and Engineering University of Electronic Science and Technology of China

Recently, how to retrieve the encrypted data efficiently from a cloud storage system becomes a hot topic. Public key encryption with keyword search(PEKS)can allow one to search the encrypted data with a keyword efficiently. Due to the booming of post-quantum cryptography, we propose public key encryption with keyword search from lattice assumption, which can resist quantum computer attacks. We delegate a particular cloud server to search the results, thus only the designated cloud server can finish the test process. Our scheme has been proved ciphertext indistinguishability in the standard model, which can reflect its security in the real world. To the best of our knowledge, our scheme is the first construction based on lattice in the standard model, which is a step stone in the post-quantum cryptographic communication.

关键词： Cloud storage Public key encryption with keyword search Lattice assumption Standard model

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A New Kind of Pilot Controlled Proportional Direction Valve with Internal Flow Feedback

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Chinese Journal of Mechanical Engineering 2010年第1期23卷 60-65页

作者： QUAN Long XU Xiaoqing YAN Zheng zhang xiaojun Institute of Mechatronics Engineering Taiyuan University of Technology Taiyuan 030024 China

Proportional direction valve is one of the most fundamental elements in electronic-hydraulic control technique. Its function is to control the operating speed, direction, position, and strength of output force of the hydraulic actuator continuously. Considering the different application and the cost, the existing technique mainly includes the internal feedback valve used in open loop system, and the electronic closed loop controlled valve used in closed loop system. Because of their different mechanical structure and the gre at different in performance, it brings inconvenience for customer to select, also inconvenience for enterprise to produce. Aiming at this problem, the idea of combining the above two kinds of valves into one body is proposed first, and then the new valve＇s structure to realize this target is designed. The idea intends to apply the displacement pilot flow feedback control principle in present 2-position 2-way valve system to the proportional direction valve of 3-position 4-way system. Newly designed feed forward controller can decouple the interference between the internal feedback and the electronic closed loop. Redundant conversion is designed to electronic switch mode. Experiment on dynamic and static characteristic of new proportional direction valve in internal feedback control mode and electronic closed loop control mode is discussed to prove the new theory is correct. Although the new valve is of excellent dynamic response characteristic, its steady control characteristic in open loop control mode needs to be improved further. The research results prepare one new fundamental element for electronic-hydraulic control technology.

关键词： pilot flow feedback proportional direction valve working principle characteristic research

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