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Comparison of Si_n^+ and Ge_n^+(n=2―15) Cationic Structures

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Chemical Research in Chinese Universities 2011年第2期27卷 313-317页

作者： QIN Wei ZANG Qing-jun LU Wen-cai WANG cai-zhuang HO Kai-ming Laboratory of Fiber Materials and Modern Textile Growing Base for State Key Laboratory College of Physics Qingdao University Qingdao 266071 P. R. China State Key Laboratory of Theoretical and Computational Chemistry Institute of Theoretical Chemistry Jilin University Changchun 130021 P. R. China College of Chemistry Beijing Normal University Beijing 100875 P. R. China Ames Laboratory-US DOE and Department of Physics and Astronomy Iowa State University Ames IA 50011 USA

We designed and optimized a large number of the isomers of Si12＋ at the level of density functional theory （DFT）-B3LYP/6-311＋＋G（d） using the Gaussian 03 software package. An unambiguous structure of the Si12＋ cluster is presented, whose IR spectrum agrees well with the experiment result. The most stable geometric structures of Gen＋（n=2―15） clusters were determined by the all-electron PBE/DND method in DMol3 of the Material Studio Package, and compared with those of the corresponding Sin＋ geometries. Most structures of Gen＋ and Sin＋ are similar except the ones of those for n=9, 12, 13 and 14, and the pentagonal bipyramid motif and the tri-capped trigonal prism（TTP） motif often appear in the Sin＋ and Gen＋（n=7―15） structures（except for Si14＋）.

关键词： Pentagonal bipyrarnid motif Tri-capped trigonal prism(TTP) motif Si.+ and Ge.+ cluster

DGR:dynamic gradient-based routing protocol for unbalanced and persistent data transmission in wireless sensor and actor networks

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第4期12卷 273-279页

作者： Yi GUO Zhe-zhuang XU cai-lian CHEN Xin-ping GUAN Department of Automation Shanghai diao Tong University Shanghai 200240 China

This paper is concerned with the routing protocol design for large-scale wireless sensor and actor networks (WSANs).The actor-sensor-actor communication (ASAC) strategy is first proposed to guarantee the reliability of persistent actor-actor *** keep network connectivity and prolong network lifetime,we propose a dynamic gradient-based routing protocol (DGR) to balance the energy consumption of the *** the different communication ranges of sensors and actors,the DGR protocol uses a data load expansion strategy to significantly prolong the network *** balance coefficient and the routing re-establishment threshold are also introduced to make the tradeoff between network lifetime and routing *** results show the effectiveness of the proposed DGR protocol for unbalanced and persistent data transmission.

关键词： Wireless sensor and actor networks Unbalanced and persistent data transmission Gradient-based routing

Melting temperature of iron under the Earth’s inner core condition from deep machine learning

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Geoscience Frontiers 2024年第6期15卷 485-493页

作者： Fulun Wu Shunqing Wu cai-zhuang Wang Kai-Ming Ho Renata M.Wentzcovitch Yang Sun Department of Physics Xiamen UniversityXiamen 361005China Department of Physics Iowa State UniversityAmesIA 50011USA Department of Applied Physics and Applied Mathematics Columbia UniversityNew YorkNY 10027USA Department of Earth and Environmental Sciences Columbia UniversityNew YorkNY 10027USA Lamont–Doherty Earth Observatory Columbia UniversityPalisadesNY 10964USA

Constraining the melting temperature of iron under Earth’s inner core conditions is crucial for understanding core dynamics and planetary ***,we develop a deep potential(DP)model for iron that explicitly incorporates electronic entropy contributions governing thermodynamics under Earth’s core *** benchmarking demonstrates the DP’s high fidelity across relevant iron phases and extreme pressure and temperature *** thermodynamic integration and direct solid–liquid coexistence simulations,the DP predicts melting temperatures for iron at the inner core boundary,consistent with previous ab initio *** resolves the previous discrepancy of iron’s melting temperature at ICB between the DP model and ab initio calculation and suggests the crucial contribution of electronic *** work provides insights into machine learning melting behavior of iron under core conditions and provides the basis for future development of binary or ternary DP models for iron and other elements in the core.

关键词： Inner core boundary Melting temperature Machine learning Solid-liquid coexistence Free energy calculation Molecular dynamics simulation

Yolk shell-structured pyrite-type cobalt sulfide grafted by nitrogen-doped carbon-needles with enhanced electrical conductivity for oxygen electrocatalysis

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Chinese Chemical Letters 2024年第7期35卷 212-217页

作者： Jiahao Xie Jin Liu Bin Liu Xin Meng zhuang cai Xiaoqin Xu Cheng Wang Shijie You Jinlong Zou Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education of the People’s Republic of ChinaSchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin 150080China School of Chemical Engineering and Light Industry Guangdong University of TechnologyGuangzhou 510006China State Key Laboratory of Urban Water Resource and Environment School of EnvironmentHarbin Institute of TechnologyHarbin 150090China

Pyrite-type sulfides(PTS)exhibit promising intrinsic activities for oxygen reduction and evolution reactions(ORR/OER).However,their poor electrical conductivities may limit the charge transfer rate to inevitably lower ***,yolk-shell structured cobalt-pyrite nanospheres(CoS_(2)YSS)are prepared and modified with amino groups as nucleation sites for coupling highly-conductive needle-like nitrogendoped carbon via a facile solvothermal method(CoS_(2)YSS@NC).The as-marked CoS_(2)YSS@NC-0.5 shows a gap between yolk and shell,and an obvious exterior layer of grafted NC,which can provide an integrated structure,an interior place,and three exposed surfaces on CoS_(2).CoS_(2)YSS@NC-0.5 reveals higher ORR activity(half-wave potential of 0.88 V)and methanol resistance than commercial Pt/*** to in-situ formation of highly-active CoOOH,CoS_(2)YSS@NC-0.5 shows a better overpotential(244 mV at 10 mA/cm^(2))and Tafel slope(135 mV/dec)than ***-air battery with CoS_(2)YSS@NC-0.5 air-cathode exhibits good open circuit potential(1.44 V),specific capacity(772.5 mAh/g)and cycling ***-like NC layer coated on the yolk-shell structure of CoS_(2)effectively lowers the charge transfer resistance to obtain extraordinary ORR/OER *** indicates that the integration of highly-conductive carbon onto pyritetype sulfides is an effective strategy to acquire durable bifunctional ORR/OER catalysts.

关键词： Cobalt sulfides Cycle stability Electrical conductivity Pyrite Yolk-shell structure

Acid-Stable CoWO_(4)/WO_(3)-Microrod Coated by a Thin Carbon-Layer as Efficient Pt Co-Catalysts for Methanol Oxidation and Oxygen Reduction

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Chinese Journal of Structural Chemistry 2022年第7期41卷 59-67页

作者： Jiahuan Li Jiahao Xie Xinyu Wang Ying Dai Xiaoqin Xu Jin Liu zhuang cai Xin Meng Jinlong Zou Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education of the People's Republic of ChinaSchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin 150080China School of Civil Engineering Heilongjiang Institute of TechnologyHarbin 150050China

Insufficient activity and instability(poisoning)of Pt-based electrocatalysts for methanol oxidation and oxygen reduction reactions(MOR/ORR)impede the development of direct methanol fuel ***,CoWO_(4) nanoparticles-loaded WO_(3) microrods coated by a thin carbon-layer are used as Pt-supports/co-catalysts for MOR/***_(3) grows along the(110)crystal plane to form microrod(diameter of~0.6 um),which is coated by a carbon-layer(~5 nm).Pt-CoWO_(4)/WO_(3)@NCL-mr(850℃)shows a higher mass activity(2208 mA mg^(-1)_(pt))than the commercial Pt/C(659.4 mA mg^(-1)_(pt)).CoWO_(4)/WO_(3) heterojunction on the microrod surface with abundant oxygen vacancies allows the generation of surface-adsorbed hydroxyl to facilitate CO elimination and regeneration of the occupied Pt active-sites(promising stability).PtCo WO_(4)/WO_(3)@NCL-mr(850℃)has higher half-wave(0.46 V)and onset(0.54 V)potentials than Pt/C(0.41 and 0.50 V)for *** microrod structure of Co WO_(4)/WO_(3)@NCL facilitates the dispersibility of Pt NPs to increase the utilization of Pt active sites and relieve the self-aggregation of Pt to obtain a promising synergy between Pt and CoWO_(4)(Co^(2+))for ORR in acid *** study provides insights not only into the synthesis of acid-resistant WO_(3)@NCL microrod as active Pt co-catalyst,but also into the effective utilization of surface oxygen vacancies and Co^(2+) for MOR/ORR.

关键词： acid resistance methanol-tolerance oxygen vacancies strong metal-support interaction thin carbon-layer

Uniformly grown PtCo-modified C03O4 nanosheets as a highly efficient catalyst for sodium borohydride electrooxidation

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Nano Research 2016年第11期9卷 3322-3333页

作者： Congying Song Dongming Zhang Bin Wang zhuang cai Peng Yan Yang Sun Ke Ye Dianxue Cao Kui Cheng Guiling Wang College of Materials Science and Chemical Engineering Harbin Engineering University Harbin 150001 China Research Center of Shanxi Province for High Gravity Chemical Engineering and Technology North University of China Taiyuan 030051 China

A facile hydrothermal synthetic method, followed by in situ reduction and galvanic replacement processes, is used to prepare PtCo-modified Co304 nanosheets （PtCo/C0304 NSs） supported on Ni foam. The prepared nanomaterial is used as an electrocatalyst for NaBH4 oxidation in alkaline solution. The morphology and phase composition of PtCo/C0304 NSs are characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD）, and X-ray photoelectron spectroscopy （XPS）. The catalytic performance of PtCo/Co3O4 NSs is investigated by cyclic voltammetry （CV） and chronoamperometry （CA） in a standard three-electrode system. Current densities of 70 and 850 mA·cm^-2 were obtained at -0.4 V for Co/Co3O4 and PtCo/Co3O4 NSs, respectively, in a solution containing 2 mol·L^-1 NaOH and 0.2 mol·L^-1 NaBH4. The use of a noble metal （Pt） greatly enhances the catalytic activity of the transition metal （Co） and Co3O4. Besides, both Co and Co3O4 exhibit good B-H bond breaking ability （in NaBH4）, which leads to better electrocatalytic activity and stability of PtCo/Co3O4 NSs in NaBH4 electrooxidation compared to pure Pt. The results demonstrate that the as-prepared PtCo/Co3O4 NSs can be a promising electrocatalyst for borohydride oxidation.

关键词： PtCo/Co3O4 nanosheets in situ reduction galvanic replacement borohydride electrooxidation

Machine learning guided discovery of ternary compounds involving La and immiscible Co and Pb elements

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npj Computational Materials 2022年第1期8卷 2462-2470页

作者： Renhai Wang Weiyi Xia Tyler JSlade Xinyu Fan Huafeng Dong Kai-Ming Ho Paul C.Canfield cai-zhuang Wang School of Physics and Optoelectronic Engineering Guangdong University of Technology510006GuangzhouChina Department of Physics and Astronomy Iowa State UniversityAmesIA50011USA Ames Laboratory-USDOE Iowa State UniversityAmesIA50011USA Department of Physics University of Science and Technology of China230026HefeiChina

Ternary compounds with an immiscible pair of elements are relatively unexplored but promising for novel quantum materials *** what third element and its ratio that can be added to make stable ternary compounds out of an immiscible pair of elements remains a great *** this work,we combine a machine learning(ML)method with ab initio calculations to efficiently search for the energetically favorable ternary La-Co-Pb compounds containing immiscible elements Co and *** previously reported structures are correctly captured by our ***,we predict a ground state La_(3)CoPb compound and 57 low-energy La-Co-Pb ternary *** to synthesize La_(3)CoPb via multiple techniques produce mixed or multi-phases samples with,at best,ambiguous signals of the predicted lowest-energy La_(3)CoPb and the second lowest-energy La_(18)Co_(28)Pb_(3)*** calculated results of Gibbs free energy are consistent with experiments,and will provide very useful guidance for further experimental synthesis.

关键词： elements immiscible ternary

Metal intercalation-induced selective adatom mass transport on graphene

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Nano Research 2016年第5期9卷 1434-1441页

作者： Xiaojie Liu cai-zhuang Wang Myron Hupalo Hai-Qing Lin Kai-Ming Ho Patricia A. Thiel Michael C. Tringides Center for Quantum Science and School of Physics Northeast Normal University Changchun 730777 China Ames Laboratory-U.S. Department of Energy and Department of Physics and Astronomy Iowa State University Ames IA 50011 USA Beijing Computational Science Research Center Beijing 100084 China Ames Laboratory-U.S. Department of Energy Department of Chemistry and Department of Materials Science and Engineering Iowa State University Ames IA 50011 USA

Recent experiments indicate that metal intercalation is a very effective method to manipulate the graphene-adatom interaction and control metal nanostructure formation on graphene. A key question is mass transport, i.e., how atoms deposited uniformly on graphene populate different areas depending on the local intercalation. Using first-principles calculations, we show that partially intercalated graphene, with a mixture of intercalated and pristine areas, can induce an alternating electric field because of the spatial variations in electron doping, and thus, an oscillatory electrostatic potential. This alternating field can change normal stochastic adatom diffusion to biased diffusion, leading to selective mass transport and consequent nucleation, on either the intercalated or pristine areas, depending on the charge state of the adatoms.

关键词： graphene intercalation electrostatic potential selective adsorption first-principle calculation

Development of a High-Temperature Thixotropic Cement Slurry System

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Fluid Dynamics & Materials Processing 2023年第11期19卷 2907-2921页

作者： Ping Lv Jiufei Liu Mengran Xu Hui Tian Huajie Liu Yuhuan Bu zhuang cai Junfeng Qu Institute of Petroleum Engineering Technology Sinopec Northwest Oil Field CompanyUrumqi830000China Xinjiang Branch of CNPC Chuanqing Drilling Engineering Company Limited Korla841000China School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580China Sinopec Shengli Petroleum Engineering Co. Ltd.DongyingChina Henan Science and Technology Innovation Promotion Center Zhenzhou450003China

Cementing carbonate reservoirs is generally a difficult *** so-called thixotropic cement slurry has gained considerable attention in this regard as it can help tofix some notable *** precisely,it can easilyfill the leakage layer;moreover,its gelling strength can grow rapidly when pumping stops,thereby increasing the resistance to gas channeling,effectively preventing this undesired phenomenon in many ***-temperature thixotropic cement slurry systems,however,are still in an early stage of development and additional research is needed to make them a viable *** the present study,using a self-developed composite high-temperature thixotropic additive as a basis,it is shown that the compressive strength can be adjusted by tuning the proportion of silica sand,the high-temperature retarder,fluid loss additive and dispersant(compatible with the thixotropic additive).According to the tests,the developed high-temperature thixotropic cement slurry system has a 14 d compressive strength of 29.73 MPa at 150°C,and a thickening time of 330 min when the dosage of retarder is 2%.At the same time,the rheological property,water loss,permeability,water separation rate,and settlement stability of the cement slurry system meet the requirements of cementing construction.

关键词： High temperature resistance thixotropy cement slurry system