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Influence of spherical inclusions on effective thermoelectric properties of thermoelectric composite materials

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Chinese Physics B 2020年第5期29卷 440-447页

作者： Wen-Kai Yan Ai-Bing Zhang Li-Jun Yi Bao-Lin Wang Ji Wang Piezoelectric Device Laboratory School of Mechanical Engineering&MechanicsNingbo UniversityNingbo 315211China Centre for Infrastructure engineering School of EngineeringWestern Sydney UniversityPenrithNSW 2751Australia

A homogenization theory is developed to predict the influence of spherical inclusions on the effective thermoelectric properties of thermoelectric composite materials based on the general principles of thermodynamics and Mori-Tanaka *** closed-form solutions of effective Seebeck coefficient,electric conductivity,heat conductivity,and figure of merit for such thermoelectric materials are obtained by solving the nonlinear coupled transport equations of electricity and *** is found that the effective figure of merit of thermoelectric material containing spherical inclusions can be higher than that of each constituent in the absence of size effect and interface *** interesting examples of actual thermoelectric composites with spherical inclusions,such as insulated cavities,inclusions subjected to conductive electric and heat exchange and thermoelectric inclusions,are considered,and the numerical results lead to the conclusion that considerable enhancement of the effective figure of merit is achievable by introducing *** this paper,we provide a theoretical foundation for analytically and computationally treating the thermoelectric composites with more complicated inclusion structures,and thus pointing out a new route to their design and optimization.

关键词： thermoelectric composites effective properties spherical inclusions

MOF-derived La/ZnO–TiO2 composite with enhanced photocatalytic ability for degradation of tetracycline

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Progress in Natural Science:Materials International 2023年第4期33卷 544-550页

作者： Lin Zhang Jun Chen Lai-Bo Song Jun-Jie Pan Qing Luo school of Physical and Healthy Education Jiangxi Science and Technology Normal University school of Chemistry and Environmental engineering Wuhan Institute of Technology Britton Chance Center for Biomedical Photonics at Wuhan National Laboratory for optoelectronics-Hubei Bioinformatics&Molecular Imaging Key Laboratory Department of Biomedical Engineering College of Life Science and Technology Huazhong University of Science and Technology Chemical Biology Center Lishui Institute of Agriculture and Forestry Sciences College of Materials Xiamen University

Developing effective and stable photocatalysts for organic pollutants degradation are still a big challenge in practical water treatment now. In this work, La doped ZnO–TiO2composite(La/ZnO–TiO2) were successfully fabricated by using PVP modified ZIF-8/TiO2as template via the absorption and pyrolysis routes. All as-fabricated materials were analyzed by XRD, SEM, TEM, BET, XPS, UV–vis absorption spectra and ESR spectra. PVP modified ZIF-8/TiO2was fully transferred into ZnO–TiO2after being pyrolyzed at high temperature under air *** doping of La can make ZnO–TiO2exhibiting red-shifted, which is attributed to the capture of photo-generated electrons by La, leading to the effective separation between photo-generated electrons and holes. Furthermore,the photocatalytic performance of all as-fabricated materials were explored by degradation of tetracycline(TC)solution under UV light irradiation. La/ZnO–TiO2exhibits excellent stability. And the photocatalytic degradation rate of La/ZnO–TiO2is 99.2%, which is even higher than ZnO(87.4%), ZnO–TiO2(87.4%), P25(TiO2)(92.7%).More than that, the effect of catalyst’s dose, effect of TC concentration and effect of pH for TC degradation have been well explored. The excellent photocatalytic performance of La/ZnO–TiO2makes it possible to be applied for degradation of organic pollutants in practice.

关键词： La/ZnO–TiO2 Red-shifted Effective separation Photocatalytic performance Tetracycline

Reductive recovery of manganese from low-grade manganese dioxide ore using toxic nitrocellulose acid wastewater as reductant

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International Journal of Minerals,Metallurgy and Materials 2018年第9期25卷 990-999页

作者： Yong-tao Zhang Zhi-gang Dan Ning Duan Bao-ping Xin school of Petroleum and Environment engineering Yan'an University school of Materials Science & engineering Beijing Institute of Technology Technology Center for Heavy Metal Cleaner Production engineering Chinese Research Academy of Environmental Sciences

The hydrometallurgical strategy of extracting Mn from low-grade Mn ores has attracted attention for the production of electrolytic manganese metal(EMM). In this work, the reductive dissolution of low-grade Mn O2 ores using toxic nitrocellulose acidic wastewater(NAW) as a reductant was investigated for the first time. Under the optimized conditions of an Mn O2 ore dosage of 100 g·L-1, an ore particle size of-200 mesh, concentrated H2 SO4-to-NAW volume ratio of 0.12, reaction temperature of 90°C, stirring speed at 160 r·min-1, and a contact time of 120 min, the reductive leaching efficiency of Mn and the total organic carbon(TOC) removal efficiency of NAW reached 97.4% and 98.5%, respectively. The residual TOC of 31.6 mg·L-1 did not adversely affect the preparation of EMM. The current process offers a feasible route for the concurrent realization of the reductive leaching of Mn and the treatment of toxic wastewater via a simple one-step process.

关键词： low-grade manganese dioxide ore nitrocellulose acid wastewater sulfuric acid leaching Mn reductive dissolution electrolytic manganese metal

A Comparative Study of Different Amorphous and Paracrystalline Silica by NMR and SEM/EDS

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Journal of Wuhan University of Technology(Materials Science) 2015年第5期30卷 900-907页

作者：贾援王宝民张婷婷 school of Civil engineering Dalian University of Technology

This work aimed to research the structure models of amorphous materials. Five amorphous and paracrystalline samples(natural or artificial) were investigated via 29Si/27 Al nuclear magnetic resonance(NMR) and field emission scanning electron microscopy/energy dispersive spectroscopy(FE-SEM/EDS). The results of NMR showed the resonances of different specimens:-93.2 ppm,-101.8 ppm,-111.8 ppm for natural pozzolana opal shale(POS). These peaks were assigned to the Q2(2OH), Q3(OH)/Q4(1Al) and Q4 respectively. The results of 27 Al MAS NMR indicated that Al substituted for Si site in tetrahedral existing in the POS, while the Al/Si atomic ratio in opal was low(around 0.04). For the alkali-silicate-hydrate gel, there were at least three resolved signals assigned to Q0 and Q1, respectively. For the fused silica glass powder, there were the primary signals centered about at the range from-107 to-137 ppm, which were assigned to Q4 units. In addition, the peaks at around-98 and-108 ppm were corresponding to Q3(1OH) and Q4 units existing in aerogel silica structure.

关键词： amorphous and paracrystalline silica the structure models NMR Al-substituted

Synthesis, Structure and Property of One Bis (benzimidazolin-2-ylidene) Arene-mercury(Ⅱ) Complex

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Chinese Journal of Structural Chemistry 2014年第11期33卷 1610-1616页

作者：李有桂韩磊马刚朱成峰 school of Chemical engineering Hefei University of Technology

Reaction of a N-heterocycliccarbene（NHC） containing an anthracene unit and two N-picolyl moieties with Hg（OAc）2 yielded a novel mercury（Ⅱ） complex（1）. X-ray studies, UV-vis and fluorescence spectroscopy confi... 详细信息

关键词： mercury benzimidazolin-2-ylidene carbine fluorescence

Attribute-based encryption resilient to continual auxiliary leakage with constant size ciphertexts

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The Journal of China Universities of Posts and Telecommunications 2016年第3期23卷 18-28页

作者： Zhang Leyou Zhang Jingxia Hu Yupu school of Mathematics and Statistics Xidian University school of Telecommunications engineering Xidian University

For leakage-resilient ciphertext-policy attribute-based encryption （CP-ABE） at present, the size of the ciphertexts in most of them relies on the number of attributes. How to overcome this shortcoming is a challenge problem. Based on the Goldreich-Levin theorem and dual system encryption, an efficient CP-ABE scheme with constant size ciphertexts is proposed in this paper. It can tolerate leakage on master secret key and attribute-based secret keys with auxiliary inputs. Furthermore, the proposed scheme can be realized as resilience against continual leakage if keys are periodically updated. Under some static assumptions instead of other strong assumptions, the introduced scheme achieves adaptively security in the standard model.

关键词： ciphertext-policy attribute-based encryption (CP-ABE) constant size ciphertexts auxiliary input leakage-resilient

A high H_2 evolution rate under visible light of a CdS/TiO_2@Ni S catalyst due to a directional electron transfer between the phases

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Chinese Journal of Chemical engineering 2019年第3期27卷 544-548页

作者： Jianling Meng Yongdan Li school of Material and Chemical engineering Tongren University Tianjin Key Laboratory of Applied Catalysis Science and Technology State Key Laboratory for Chemical Engineering School of Chemical Engineering Tianjin University

The photocatalytic activity of CdS can be greatly improved by co-modification of NiS and TiO_2 materials; furthermore the order of connection affects much. A directional electron transfer route via CdS → TiO_2→ NiS is found crucial to the enhancement of ternary catalyst, where TiO_2 acts as an electron reservoir and Ni S works as an effective cocatalyst. Cd S/TiO_2@Ni S with Ni S loaded on TiO_2 has an activity of H_2 evolution 2.5 times higher than NiS@Cd S/TiO_2 with Ni S pre-loaded on Cd S. Faster e-/h+separation rates is obtained of Cd S/TiO_2@Ni S under visible light than under extra UV light irradiation, which in turn demonstrates the importance of directional electron transfer route.

关键词： Directional electron transfer Photocatalysis Hydrogen Visible light

Extension of the rotating dipole model with oblateness of both primaries

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Research in Astronomy and Astrophysics 2017年第1期17卷 11-20页

作者： Xiang-Yuan Zeng Xiang-Dong Liu Jun-Feng Li school of Automation Beijing Institute of Technology school of Aerospace engineering Tsinghua University

A rotating mass dipole can be used to understand the dynamical behaviors around elongated asteroids as well as binary asteroids. In this paper an improved dipole model with oblateness in both primaries is investigated. The dynamical equations of a particle around the improved model are first derived by introducing the oblateness coefficients. The characteristic equations of equilibrium points are obtained, resulting in the emergence of new equilibria in the equatorial plane and the plane xoz de- pending on the shape of the spheroid. Numerical simulations are performed to illustrate the distribution of these equilibrium points. Significant influence from the oblateness of the primaries on the topological structure is also analyzed via zero-velocity curves.

关键词： celestial mechanics - minor planets, asteroids general - methods numerical

Synthesis,structural characterization and properties of a 3D infinitely extended structural rare earth coordination compound of K_3{[Sm(H_2O)_7]_2Na[α-SiW_(11)O_(39)Sm(H_2O)_4]_2}·14 H_2O

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Science China Chemistry 2005年第4期48卷 343-351页

作者： WANG Jingping ZHAO Junwei NIU Jingyang Institute of Molecule and Crystal engineering School of Chemistry and Chemical EngineeringHenan UniversityKaifeng 475001China Institute of Molecule and Crystal EngineeringSchool of Chemistry and Chemical EngineeringHenan UniversityKaifeng 475001China Institute of Molecule and Crystal EngineeringSchool of Chemistry and Chemical EngineeringHenan UniversityKaifeng 475001China

A 3D infinitely extended structural rare earth coordination compound with a formula of K3{[Sm(H2O)7]2Na[a-SiW11O39Sm(H2O)4]2}·14H2O has been synthesized by reaction of Sm2O3,HClO4,NaOH with a-K8SiW11O39·nH2O,and characterized by IR,UV spectra,ICP,TG-DTA,cyclic voltammetry,variable-temperature magnetic susceptibility and X-ray single-crystal diffrac-tion.X-ray single-crystal diffraction indicates that the title compound crystallizes in a triclinic lat-tice,Pi space group,with a = 1.2462(3) nm,b = 1.2652(3) nm,c = 1.8420(4) nm,α = 87.45(3)°,β = 79.91(3)°,γ = 82.57(3)°,Z = 1,R1 = 0.0778,wR2 = *** analysis reveals that Sm3+(1) coordination cation has incorporated into the vacant site of [α-SiW11O39]8? entity,forming the [α-SiW11O39Sm(H2O)4]5? *** two adjacent [a-SiW11O39Sm(H2O)4]5? subunits are combined with each other through two Sm(1)-O-W bridges accompanying the formation of dim-mer structural unit [α-SiW11O39Sm(H2O)4]210? of the title *** neighboring dimmer structural units [α-SiW11O39Sm(H2O)4]210? are linked to form the 1D chainlike structure by means of two Sm3+(2) and a Na+(1) coordination *** K+(1) cations connect the 1D packing chains constructing the 2D netlike structure,and adjacent netlike layers are also grafted by K+(2) cations to build the novel 3D infinitely extended *** result of TG-DTA curves manifests that the decomposition temperature of the title polyanionic framework is 554℃.The cyclic volt-ammetry measurements show that the title polyanion has the two-step redox processes in aqueous solution with pH = *** temperature magnetic susceptibility indicates the title compound obeys the Cruie-Weiss Law in the higher temperature range from 110 to 300 K,while in the lower temperature range from 2 to 110 K the comparatively strong antiferromagnetism in-teractions can be observed.

关键词： silicotungstic acid, Keggin structure, crystal structure, polyoxometalates, rare earth metal.