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Kinetics and corrosion products of aqueous nitrate reduction by iron powder without reaction conditions control

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Journal of Environmental Sciences 2009年第8期21卷 1028-1035页

作者： FAN Xiaomeng guan Xiaohong ma Jun AI Hengyu School of Municipal and Environmental Engineering Harbin Institute of Technology Harbin 150090 China College of Chemical and Environmental Engineering Harbin University of Science and Technology Harbin 150080 China

Although considerable research has been conducted on nitrate reduction by zero-valent iron powder （Fe^0）, these studies were mostly operated under anaerobic conditions with invariable pH that was unsuitable for practical application. Without reaction conditions （dissolved oxygen or reaction pH） control, this work aimed at subjecting the kinetics of denitrification by microscale Fe^0 （160-200 mesh） to analysis the factors affecting the denitrification of nitrate and the composition of iron reductive products coating upon the iron surface. Results of the kinetics study have indicated that a higher initial concentration of nitrate would yield a greater reaction rate constant. The reduction rate of nitrate increased with increasing Fe^0 dosage. The reaction can be described as a pseudo-first order reaction with respect to nitrate concentration or Fe^0 dosage. Experimental results also suggested that nitrate reduction by microscale Fe^0 without reaction condition control primarily was an acid-driven surface-mediated process, and the reaction order was 0.65 with respect to hydrogen ion concentration. The analyses of X-ray diffractometry and X-ray photoelectron spectroscopy indicated that a black coating, consisted of Fe2O3, Fe3O4 and FeO（OH）, was formed on the surface of iron grains as an iron corrosion product when the system initial pH was lower than 5. The proportion of FeO（OH） increased as reaction time went on, whereas the proportion of Fe3O4 decreased.

关键词： kinetics nitrate reduction zero-valent iron corrosion products pH

Diesel molecular composition and blending modeling based on SUBEM framework

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Petroleum Science 2022年第2期19卷 839-847页

作者： Yue-Ming guan Dong guan Cheng Zhang sheng-Hua Yuan guang-Qing Cai Lin-Zhou Zhang State Key Laboratory of Heavy Oil Processing Petroleum Molecular Engineering Center(PMEC)China University of PetroleumBeijing102249China SINOPEC Dalian Research Institute of Petroleum and Petrochemicals SINOPECDalian116045LiaoningChina

Diesel molecular compositional model has important application for diesel quality prediction,blending,and molecular-level process model *** this paper,different types of diesel molecular compositional and blending models were constructed based on the SU-BEM *** than 1500 representative molecules were selected to form the molecular structure *** probability density functions(PDFs)combination was determined by experimental data and experience.A quadratic optimization strategy combining genetic algorithm with local optimization algorithm was adopted to improve the accuracy of the compositional *** model results show good agreement with the experimental *** diesel blending model was constructed at the molecular-level based on the above diesel compositional *** properties of the blending model accord with the experimental *** is proved that the compositional models and blending model constructed have high accuracy and strong prediction capability,and are applicable to the industrial process.

关键词： Molecular compositional model Molecular blending model SU-BEM Framework Diesel

GITAR: An Open Source Tool for Analysis and Visualization of Hi-C Data

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Genomics, Proteomics & Bioinformatics 2018年第5期16卷 365-372页

作者： Riccardo Calandrelli Qiuyang Wu Jihong guan sheng Zhong Department of Bioengineering University of California San Diego Department of Computer Science and Technology Tongji University

Interactions between chromatin segments play a large role in functional genomic assays and developments in genomic interaction detection methods have shown interacting topological domains within the genome. Among these methods, Hi-C plays a key role. Here, we present the Genome Interaction Tools and Resources(GITAR), a software to perform a comprehensive Hi-C data analysis, including data preprocessing, normalization, and visualization, as well as analysis of topologically-associated domains(TADs). GITAR is composed of two main modules:(1)HiCtool, a Python library to process and visualize Hi-C data, including TAD analysis; and(2)processed data library, a large collection of human and mouse datasets processed using *** leads the user step-by-step through a pipeline, which goes from the raw Hi-C data to the computation, visualization, and optimized storage of intra-chromosomal contact matrices and TAD coordinates. A large collection of standardized processed data allows the users to compare different datasets in a consistent way, while saving time to obtain data for visualization or additional analyses. More importantly, GITAR enables users without any programming or bioinformatic expertise to work with Hi-C data. GITAR is publicly available at http://*** as an open-source software.

关键词： Chromatin interaction Pipeline Hi-C data normalization Topologically-associated domain Processed Hi-C data library

Towards an understanding of plant reproductive isolation:uncovering the species-specific signal for pollen tube guidance

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Science China(Life Sciences) 2020年第4期63卷 620-622页

作者： Xin-Qi Gao Huan guan Xian-sheng Zhang National Key Laboratory of Crop Biology College of Life SciencesShandong Agricultural UniversityTai’an 271018China

Fertilization produces diploid zygote as the initiation of new diploid organism by fusing two haploid gametes(sperm and egg cell).Different from animals,plants in angiosperms produce immobile sperms in pollen/pollen tube(male gametophyte).Whereas,the egg cell is located in the female gametophyte(embryo sac)that consists of two female gametes(egg and central cells)and accessory cells(synergids and antipodals).Embryo sac is embedded in the ovule of ovary,which is an enlarged basal portion of the *** growth of pollen tube provides a strategy for the immobile sperm approaching the egg *** pollination,pollen germinates at the surface of the stigma and produces pollen *** grows through the transmitting tract of the style and emerges from it to enter the ovary in response to certain attracting cues from the ovule.

关键词： attracting approaching tube

Impact of oceans on climate change in drylands

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Science China Earth Sciences 2019年第6期62卷 891-908页

作者： Xiaodan guan Jieru ma Jianping HUANG Ruixin HUANG Lei ZHANG Zhuguo ma Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric Sciences Lanzhou University Woods Hole Oceanographic Institution State Key Laboratory of Tropical Oceanography South China Sea Institute of Oceanology Chinese Academy of Sciences Key Laboratory of Regional Climate-Environment for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences

Drylands account for approximately 41% of the global total land area. Significant warming and rare precipitation in drylands result in a fragile ecology and deterioration of the living environment, making it more sensitive to global climate change. As an important regulator of the Earth's climate system, the oceans play a vital role in the process of climate change in drylands. In modern climate change in particular, the impact of marine activities on climate change in drylands cannot be neglected. This paper reviews the characteristics of climate change in drylands over the past 100 years, and summarizes the researches conducted on the impact of marine activities on these changes. The review focuses on the impact of the Pacific Decadal Oscillation(PDO), Atlantic Multidecadal Oscillation(AMO), El Ni?o and La Ni?a on climate change in drylands, and introduces the mechanisms by which different oceanic oscillation factors synergistically affect climate change in *** have shown that global drylands have experienced a significant intensification in warming in the past 100 years, which shows obvious characteristics of interdecadal dry/wet variations. The characteristics of these changes are closely related to the oscillatory factors of the oceanic interdecadal scale. Different phase combinations of oceanic oscillation factors significantly change the land-sea thermal contrast, which in turn affects the westerly jet, planetary wave and blocking frequency, resulting in changes in the temperature and dry/wet characteristics of drylands. With the intensification of climate change in drylands, the impact of marine activities on these regions will reveal new characteristics in the future, which will increase the uncertainty of future climate change in drylands and intensify the impact of these drylands on global climate.

关键词： Impact of oceans on climate change in drylands AMO

Preparation and performance of a cold gas dynamic sprayed high-aluminum bronze coating

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International Journal of Minerals,Metallurgy and materials 2018年第11期25卷 1354-1361页

作者： Li Feng Chang guan Ji-rong Chang Hai-min Zhai Guo-sheng An Wen-sheng Li School of materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou 730050China

By mixing preheated high-aluminum bronze powders with different amounts of Al_2O_3 powder, a low-pressure cold-sprayed coating was prepared and sprayed onto a Cr12MoV steel substrate. The hardness of the coating and the bonding strength between the coating and the substrate were tested with a HV-1000 microhardness tester and a mechanical universal testing machine. The surface microstructure, cross-section and tensile fracture surface of the coating were observed with a scanning electron microscope(SEM). Correspondingly, the influences of the preheat treatment temperature of the bronze powder and the Al_2O_3 content on the coating performance were investigated. The results indicate that the hardness of bronze powders decreased and the coating deposition rate increased after the preheating treatment of the bronze powder. The Al_2O_3 content in the mixed powders contributed to the deformation of bronze powders during the spraying process. This trend resulted in varied performance of the coating.

关键词： low-pressure cold spray high-aluminum bronze preheat treatment coating performance

Influence of Grain Orientation on the Corrosion Behavior of Rolled AZ31 magnesium Alloy

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Acta Metallurgica Sinica(English Letters) 2015年第11期28卷 1387-1393页

作者： Yan-Chun Zhao guang-sheng Huang guan-Gang Wang Ting-Zhuang Han Fu-sheng Pan State Key Laboratory of Mechanical Transmission College of Materials Science and EngineeringChongqing University National Engineering Research Center for magnesium Alloys Chongqing University Chongqing Research Center for Advanced materials Chongqing Academy of Science and Technology

The effect of the grain orientation on corrosion behavior of rolled AZ31 magnesium alloy is investigated in this study. The test samples have a similar surface roughness to the Mg alloy in practical application. The immersion test and electrochemical impedance spectroscopy show that the TD-ND planes dominated by （101-0）, （1120） and （1011） oriented grains show a higher corrosion resistance compared with these of the RD-TD planes which consist mainly of （0001） oriented grains. Here, RD, ND and TD represent the rolling direction, the normal direction and the transverse direction of the alloy sheet, respectively. The surface morphologies of the alloys at various immersion stages are observed by scanning electron microscopy, and the surface topography of the alloy substitutes is also observed by laser scanning confocal microscopy. The TD-ND planes show a regular corrosion along the TD direction, but the RD-TD plane shows an irregular corrosion.

关键词： magnesium alloys Corrosion behavior Electrochemical impedance spectroscopy Crystallographic orientation

Structural optimization and design of purging plug for improving its service performance

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Journal of Iron and Steel Research International 2022年第4期29卷 628-635页

作者： Fang-guan Tan sheng-li Jin Zhu He Ya-wei Li The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina National-Provincial Joint Engineering Research Center of High Temperature materials and Lining Technology Wuhan University of Science and TechnologyWuhan 430081HubeiChina Chair of Ceramics Montanuniversitaet LeobenLeoben 8700Austria

Purging plug with slits is widely used in the secondary refining process,and its service life determines the downtime and production *** achieve a good performance in service life,optimizing the geometric structure of the slit,which can alleviate the stress concentration around the slit,was employed using the finite plate ***,the performance of the purging plugs with different shapes of slits in the refining effect was investigated by conducting the water model *** numerical simulation results showed that the appropriate shapes of slits could alleviate the stress concentration *** the water model experiment,the mixing time of the purging plug with circular slits is lesser than that of the purging plug with rectangular slits when the gas flow is less than 6.02 L/*** with the rectangular slits,the circular slits are detrimental to smaller and well-distributed ***,the inclusion removal rate of the purging plug with circular slits is approximately 10%larger than that of the purging plug with the rectangular slits.

关键词： Purging plug Stress concentration Water model experiment Mixing time Inclusion removal Ladle metallurgy

The Christoffel-Minkowski Problem II: Weingarten Curvature Equations

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Chinese Annals of mathematics,Series B 2006年第6期27卷 595-614页

作者： Pengfei guan Changshou LIN Xi＇nan ma Department of mathematics McGill University Montreai Quebec H3A 2K6 Canada Department of mathematics National Chung Cheng University Chia-Yi Taiwan China Department of mathematics University of Science and Technology of China Hefei 230026 China

In this paper the authors discuss the existence and convexity of hypersurfaces with prescribed Weingarten curvature.

关键词： Existence Convexity Weingarten curvature