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Effect of Potassium and C/N Ratios on Conversion of NH_4^+ in Soils

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Pedosphere 2008年第4期18卷 539-544页

作者： TANG Yan WANG Xiao-zhi zhao Hai-Tao FENG Ke College of Environment Science and Engineering Yangzhou University Yangzhou 225009 （China）

Two soils, one consisting of 1:1 clay minerals at pH 4.5 and the other containing 2:1 clay minerals at pH 7.0, were used to estimate the conversion of added NH+4 under different C/N ratios (glucose as the C source) and the addition of potassium. Under lower C/N ratios (0:1 and 5:1), a large part of the added NH4+ in the acid soil was held in the forms of either exchangeable or water soluble NH4+ for a relatively long time and under higher C/N ratio (50:1), a large amount of the added NH4+ was directly immobilized by microorganisms. In the second soil containing appreciable 2:1 type clay minerals a large part of the added NH+4 at first quickly entered the interlayer of the minerals under both lower and higher C/N ratios. In second condition, however, owing to microbial assimilation stimulated by glucose the newly fixed NH4+c ould be completely released in further incubation because of a large concentration gradient between external NH4+ and fixed NH4+ in the mineral interlayer caused by heterotrophic microorganisms, which imply the fixed NH4+ to be available to plants. The results also showed that if a large amount of K+ with carbon source together was added to soil, the higher K+ concentration of soil solution could impede the release of fixed NH4+ , even if there was a lot of carbon source.

关键词： clay minerals fixed NH4^+ N mineralization organic C potassium

Exploring the initial oxidation of Pt,Pt_(3)Ni,Pt_(3)Au(111)surfaces:a genetic algorithm based global optimization with density functional theory

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Green Chemical Engineering 2020年第1期1卷 56-62页

作者： Sihang Liu Jie Zong zhi-Jian zhao Jinlong Gong School of Chemical Engineering and Technology Key Laboratory for Green Chemical Technology of Ministry of EducationTianjin UniversityTianjin300072China Collaborative Innovation Center of Chemical Science and Engineering Tianjin300072China Department of Chemistry The Pennsylvania State UniversityUniversity ParkPA 16802USA Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityBinhai New CityFuzhou350207China

Noble metal alloys are one of the most commonly used heterogeneous *** many reactions,the surface composition and oxidation states of the noble metal alloy particles have been reported to be *** paper describes a density functional theory study to explore the initial oxidation stages of the Ptbased surfaces,which are widely-used catalysts in various clean energy conversion *** applying a genetic algorithm based global optimization,we identified new surface phases at relatively high O coverages,1 ML and 3/2 ML,on Pt and Pt alloy(111)*** existence of O transforms the metallic surfaces,creating oxide skins with different morphology and *** with higher reducibility are pulled out to the outmost surface,to bind with O *** lattice constant affects the binding strength of O atoms over certain oxide ***,the strain effect plays a crucial role in the formation of oxide overlayers.

关键词： alloy theory optimization

Applications of in-situ spectroscopic techniques towards CO_(2)electroreduction

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Science China Chemistry 2024年第12期67卷 3925-3933页

作者： Haoyu Zhang Chaoyue Gu Minghui Fan zhi zhao Xiangdong Kong zhigang Geng Hefei National Research Center for Physical Sciences at the Microscale Department of ChemistryUniversity of Science and Technology of ChinaHefei 230026China The Instruments Center for Physical Science University of Science and Technology of ChinaHefei 230026China

In-situ experimental techniques have been widely applied to uncover the dynamic evolutions of both the structure of catalysts and the interfacial property of catalysis,thus serving as the most important means to gain molecular-level insights into the reaction *** this mini review,we summarized recent progress in the applications of the interface-sensitive in-situ Raman and in-situ infrared(IR)spectroscopy towards CO_(2)***,we concentrated on two aspects to clarify the role of both in-situ Raman and in-situ IR in revealing reaction mechanisms of CO_(2)*** first one was the in-situ spectroscopy for detecting the active *** other one was the in-situ spectroscopy for capturing the reaction *** powerful guidance for the rational design of catalysts,the reaction mechanism was discussed in the specific ***,we try to predict the trends for the future development of in-situ spectroscopic techniques towards heterogeneous catalysis.

关键词： in-situ Raman in-situ IR active structure of catalysts reaction intermediates CO_(2)electroreduction

Synthesis of vanadium and chromium carbides(V_8C_7–Cr_3C_2) nanocomposite via an in situ precursor method

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Rare Metals 2015年第7期34卷 498-504页

作者： zhi-Wei zhao Wen-Meng Hu Hong-Juan Zheng Fei-Xiao Chen College of Materials Science and Engineering Henan University of Technology

In situ synthesis method was used to prepare V8C7–*** vanadate, ammonium dichromate and nanometer carbon black were used as raw *** products were characterized by X-ray diffractometry(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), thermogravimetric and differential scanning calorimetry(TGDSC) and X-ray photoelectron spectroscopy(XPS) *** results show that V8C7–Cr3C2nanocomposite with an average crystallite size of 25.4 nm can be synthesized at 1200 °C for 1 *** synthesis temperature required by the method is at least 200 °C lower than that required by the conventional approaches for preparing vanadium and chromium *** powders show good dispersion and are mainly composed of spherical or nearly spherical particles with a mean diameter of about 30 *** weight loss ratio of the precursor throughout the reaction process reaches 58 wt%.Three exothermic peaks and four endothermic peaks occur during the *** surface of the specimen is mainly composed of V, Cr, C and O elements.

关键词： Nanocomposite Carbides Precursor In situ synthesis

Sparse antenna array design methodologies:A review

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Journal of Electronic Science and Technology 2024年第3期22卷 1-15页

作者： Pan Wu Yan-Hui Liu zhi-Qin zhao Qing-Huo Liu School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China Eastern Institute of Technology Ningbo315200China

Designing a sparse array with reduced transmit/receive modules(TRMs)is vital for some applications where the antenna system’s size,weight,allowed operating space,and cost are *** arrays exhibit distinct architectures,roughly classified into three categories:Thinned arrays,nonuniformly spaced arrays,and clustered *** numerous advanced synthesis methods have been presented for the three types of sparse arrays in recent years,a comprehensive review of the latest development in sparse array synthesis is *** work aims to fill this gap by thoroughly summarizing these *** study includes synthesis examples to facilitate a comparative analysis of different techniques in terms of both accuracy and ***,this review is intended to assist researchers and engineers in related fields,offering a clear understanding of the development and distinctions among sparse array synthesis techniques.

关键词： Clustered array Nonuniformly spaced array Sparse antenna array Synthesis method Thinned array

Electron Transport through Hydrogen Bonded Single-Molecule Junctions

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Chinese Journal of Chemistry 2023年第23期41卷 3433-3446页

作者： Jiu-Hong Fang zhi-Hao zhao Ang-Xuan Li Lin Wang 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)Beijing100083 China State Key Laboratory of Solidification Processing and School of Materials Science and Engineering Northwestern Polytechnical UniversityXi'anShaanxi710072 China

Hydrogen bonding is a vital driving force for organizing the hierarchy of molecular structure,especially in biologic *** to its directionality,selectivity and moderate strength,hydrogen bonding has been extensively introduced into the molecular recognition,sensing and electronic *** measurements at single-molecule level facilitate the investigation of hydrogen bonds and provide a comprehensive understanding of the electron transport properties governed by the hydrogen bonding,which is essential for the development of self-assembled electronic *** review provides a detailed overview of recent advancements in constructing single-molecule junctions utilizing intramolecular and intermolecular hydrogen *** first introduce the methods utilized for characterizing the electric and dynamic properties of non-covalent ***,we discuss the mechanisms of electron transport,relevant influencing factors,and typical applications utilizing electrical signals based on single-molecule ***,we propose our perspective on the existing challenges and prospective opportunities in utilizing hydrogen bonding for electronic device applications.

关键词： Electron transport Hydrogen bond Single-molecule junction Molecular devices Molecular assembly

Microstructure and microhardness of directionally solidified NiAl-W eutectic alloy

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Rare Metals 2020年第10期39卷 1174-1180页

作者： Jian-Jun Gao zhi-Long zhao Lu-Feng Wei Kai Cui Lin Liu School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350108China School of Mechanical Engineering Northwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China

The microstructure and microhardness of directionally solidified NiAl-W eutectic alloys at growth rates of 2-25μm·s^-1 were investigated by a Bridgman crystal growing facility at a temperature gradient of 300 K·cm^-*** view of the competitive growth between W dendritic and eutectic phases,W dendritic phase was eliminated,whereas the fully eutectic phase was prominent in the steady progress of the directionally solidified NiAl-W eutectic *** the growth rate(V)increased,both the structure and solid/liquid interface of the directionally solidified NiAl-W eutectic alloys changed from planar to *** the fibrous spacing(d)and the diameter(a)decreased with increase in growth rate(V).The Vickers microhardness(H)of the directionally solidified NiAl-W eutectic alloys decreased with fibrous spacing(d)or diameter(a)*** relationships of H to d and a were H=371.58 d^(-0.09)and H=297.70 a^(-0.09),respectively.

关键词： Microstructure Directional solidification Eutectic alloy Microhardness

Modification of TiN Coatings by N^(+) and C^(+) Implantation with High Ion Flux

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Chinese Physics Letters 1999年第3期16卷 196-198页

作者： ZHANG Tong-he WU Yu-guang zhao zhi-yong DENG zhi-wei Institute of Low Energy Nuclear Physics Radiation Beam and Materials Engineering Open Laboratory of Department of Education of ChinaBeijing Radiation CenterBeijing Normal UniversityBeijing 100875

The TiN coating changed from columnar structure to compact texture after N^(+)and C^(+)implantation.X-ray analysis showed that combining with N atoms,Ti and Ti_(2)N would be transformed into TiN Phases during N *** ternary solid solution mixtures TiCN have been formed,while Ti,Ti_(2)N would be transformed into TiC and TiCN phases combining with C atoms after C *** hardness of the TiN coating increased by 2.3-2.4 times after N^(+)or C^(+)*** wear resistance of implanted TiN coatings is 2-3 times higher than that of unimplanted TiN *** the drills were treated with the method,their lifetime would increase by 7 times comparing with unimplanted *** an attractive procedure,the ion implantation of the TiN coatings would find new applications in many fields.

关键词： coating wear resistance

Microstructure and mechanical properties of the welding joint filled with microalloying 5183 aluminum welding wires

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International Journal of Minerals,Metallurgy and Materials 2014年第6期21卷 577-582页

作者： Zhen Xu zhi-hao zhao Gao-song Wang Chao Zhang Jian-zhong Cui The Key Laboratory of the Ministry of Education of China for Electromagnetic Processing of Materials Northeastern University

In this study, 7A52 aluminum alloy sheets of 4 mm in thickness were welded by tungsten inert gas welding using microalloying welding wires containing traces of Zr and Er. The influence of rare earth elements Zr and Er on the microstructure and mechanical properties of the welded joints was analyzed by optical microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, hardness testing, and tensile mechanical properties testing. Systematic analyses indicate that the addition of trace amounts of Er and Zr leads to the formation of fine Al3Er, Al3Zr, and Al3（Zr,Er） phases that favor significant grain refinement in the weld zone. Besides, the tensile strength and hardness of the welded joints were obviously improved with the addition of Er and Zr, as evidenced by the increase in tensile strength and elongation by 40 MPa and 1.4%, respectively, and by the welding coefficient of 73%.

关键词： aluminum alloys inert gas welding rare earth elements microalloying joints microstructure mechanical properties