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Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

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Science China Chemistry 2025年第01期 288-296页

作者： Shuai Liu Wen-Qiang Xu Ying-Tong Di man-cheng Tang Ding-Kang Chen Ming-Ming Cao Yao-Wen Chang Hong-Yu Tang Chun-Mao Yuan Jun-Bo Yang Zhi-Li Zuo Han Guo Zi-Fei Xu Ying Zeng Yun-Dong Wu Xiao-Jiang Hao Key Laboratory of Phytochemistry and Natural Medicines (Chinese Academy of Sciences) Kunming Institute of Botany Chinese Academy of Sciences University of Chinese Academy of Sciences Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical Oncogenomics Peking University Shenzhen Graduate School Shenzhen Bay Laboratory State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical University Molecular Biology Experimental Center Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences Yunnan Key Laboratory for Wild Plant Resources Kunming Institute of Botany Chinese Academy of Sciences Research Unit of Chemical Biology of Natural Anti-Virus Products Chinese Academy of Medical Sciences

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase Spe F and P450 monooxygenase Spe G, is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide B. Using notoamide E as a substance, Spe F/Spe G metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-m A with dienyl iminium unit. Subsequently,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

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Responses of soil nitrogen, phosphorous and organic matter to vegetation succession on the Loess Plateau of China

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Journal of Arid Land 2015年第2期7卷 216-223页

作者： man cheng Shao Shan AN College of Natural Resources and Environment Northwest A&F University State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Northwest A&F University

Revegetation is a traditional practice widely used for soil protection. We evaluated the effect of natural revegetation succession on soil chemical properties and carbon fractions （particulate organic carbon （POC）, humus carbon （HS-C）, humic acid carbon （HA-C） and fulvic acid carbon （FA-C）） on the Loess Plateau of China. The vegetation types, in order from the shortest to the longest enclosure duration, were：（a） abandoned overgrazed grassland （AbG3; 3 years）; （b） Hierochloe odorata Beauv. （HiO7; 7 years）; （c） Thymus mongoficus Ronnm （ThM15; 15 years）; （d） Artemisia sacrorum Ledeb （AtS25; 25 years）; （e） Stipa bungeana Trin Ledeb （StB36; 36 years） and （f） Stipa grandis P. Smirn （StG56; 56 years）. The results showed that the concentrations of soil organic carbon, total nitrogen and available phosphorus increased with the increase of restoration time except for ThM15. The concen- tration of NH4-N increased in the medium stage （for ThM15 and AtS25） and decreased in the later stage （for StB36 and StG56） of vegetation restoration. However, NO3-N concentration significantly increased in the later stage （for StB36 and StG56）. Carbon fractions had a similar increasing trend during natural vegetation restoration. The con- centrations of POC, HS-C, FA-C and HA-C accounted for 24.5%-49.1%, 10.6%-15.2%, 5.8%-9.1% and 4.6%-6.1% of total carbon, respectively. For AbG3, the relative changes of POC, HS-C and FA-C were significantly higher than that of total carbon during the process of revegetation restoration. The higher relative increases in POC, HS-C and FA-C confirmed that soil carbon induced by vegetation restoration was sequestrated by higher physical and chemical protection. The increases of soil C fractions could also result in higher ecological function in semiarid grassland ecosystems.

关键词： particulate organic carbon humus carbon humic acid carbon fulvic acid carbon carbon fraction natural vegetation succession

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Analysis of destructive effect of Zn on carbon brick and way of Zn into carbon brick

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Journal of Iron and Steel Research International 2024年第6期31卷 1344-1354页

作者： Peng-bo Liu Shu-sen cheng Yu-qing Xue Xiao-man cheng Zhao Liu University of Science and Technology Beijing Beijing 100083China Ministry of Ironmaking Shangdong Taishan Steel Group Co.Ltd.Taian 271000ShandongChina

The service life of a blast furnace depends largely on the degree of damage to the carbon brick in the *** brick and ramming material in the hearth of a 1780 m3 blast furnace after shutdown were sampled and *** was found that the substances in the cracks of the carbon brick near and above the taphole were ZnO and Zn_(2)SiO_(4),whereas the substances in the cracks of the carbon brick below the taphole were *** reaction of Zn with CO,SiO_(2),and Fes generates ZnO,Zn_(2)SiO_(4),and ZnS,resulting in volume expansion,which is an important reason for the cracking of carbon ***,several obvious Zn vapor flow channels were found in the ramming material,through which Zn vapor could enter the carbon brick,causing damage to the carbon *** the compactness of the ramming material is beneficial to preventing Zn vapor from entering the carbon brick through the voids in the ramming material,reducing the destructive effect of Zn on the carbon brick and further extending the service life of the blast furnace.

关键词： Zn Blast furnace Carbon brick Ramming material Crack

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Mechanical properties and corrosion behavior of selective laser melted 316L stainless steel after different heat treatment processes

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Journal of Materials Science & Technology 2019年第7期35卷 1499-1507页

作者： Decheng Kong Chaofang Dong Xiaoqing Ni Liang Zhang Jizheng Yao cheng man Xuequn cheng Kui Xiao Xiaogang Li Beijing Advanced Innovation Center for Materials Genome Engineering Key Laboratory for Corrosion and Protection (MOE)Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China Shanghai Engineering Research Center of 3D Printing Materials Shanghai Research Institute of MaterialsShanghai 200437China School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China

Irregular grains, high interfacial stresses and anisotropic properties widely exist in 3D-printed metallic materials, and this paper investigated the effects of heat treatment on the microstructural, mechanical and corrosion properties of 316 L stainless steel fabricated by selective laser melting. Sub-grains and low-angle boundaries exist in the as-received selective laser melted(SLMed) 316 L stainless steel. After heat treatment at 1050℃, the sub-grains and low-angle boundaries changed slightly, and the stress state and strength decreased to some extent due to the decrease of dislocation density. After heat treatment at 1200℃, the grains became uniform, and the dislocation cells vanished, which led to a sharp decline in the hardness and strength. However, the ductility was improved after recrystallization heat *** passive film thickness and corrosion potential of the SLMed 316 L stainless steel decreased after heat treatment, and the pitting potential also decreased due to the accelerated transition from metastable to steady-state pitting;this accelerated transition was caused by the presence of weak passive films at the enlarged pores after heat treatment, especially for an adequate solid solution treatment.

关键词： 316L stainless steel Selective laser melting Heat treatment Microstructure Mechanical property Corrosion behaviour

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Microstructure and mechanical properties of nickel-based superalloy fabricated by laser powder-bed fusion using recycled powders

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International Journal of Minerals,Metallurgy and Materials 2021年第2期28卷 266-278页

作者： De-cheng Kong Chao-fang Dong Xiao-qing Ni Liang Zhang Rui-xue Li Xing He cheng man Xiao-gang Li Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Shanghai Engineering Research Center of 3D Printing Materials Shanghai Research Institute of MaterialsShanghai 200437China School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China

Evaluating the recyclability of powders in additive manufacturing has been a long-term *** this study,the microstructure and mechanical properties of a nickel-based superalloy fabricated by laser powder-bed fusion(LPBF)using recycled powders were ***-melted powder surfaces,satellite particles,and deformed powders were found in the recycled powders,combined with a high-oxygencontent surface *** increasing oxygen content led to the formation of high-density oxide inclusions;moreover,printing-induced cracks widely occurred and mainly formed along the grain boundaries in the as-built LPBF nickel-based superalloys fabricated using recycled powders.A little change in the Si or Mn content did not increase the hot cracking susceptibility(HCS)of the printed *** changing aspect ratio and the surface damage of the recycled powders might contribute to increasing the crack ***,the configuration of cracks in the as-built parts led to anisotropic mechanical properties,mainly resulting in extremely low ductility vertical to the building direction,and the cracks mainly propagated along the cellular boundary owing to the existence of a brittle precipitation phase.

关键词： laser powder-bed fusion recycled powder cracking anisotropy nickel-based superalloy

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Effect of microstructure on corrosion behavior of high strength martensite steel-A literature review

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International Journal of Minerals,Metallurgy and Materials 2021年第5期28卷 754-773页

作者： Li Wang Chao-fang Dong cheng man Ya-bo Hu Qiang Yu Xiao-gang Li Beijing Advanced Innovation Center for Materials Genome Engineering Key Laboratory for Corrosion and Protection(MOE)Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China Hunan Valin Lianyuan Iron and Steel Co.Ltd Loudi 417009China

The high strength martensite steels are widely used in aerospace,ocean engineering,etc.,due to their high strength,good ductility and acceptable corrosion *** paper provides a review for the influence of microstructure on corrosion behavior of high strength martensite *** is the most common corrosion type of high strength stainless steels,which always occurs at weak area of passive film such as inclusions,carbide/intermetallic ***,the chromium carbide precipitations in the martensitic lath/prior austenite boundaries always result in intergranular *** precipitation,dislocation and grain/lath boundary are also used as crack nucleation and hydrogen traps,leading to hydrogen embrittlement and stress corrosion cracking for high strength martensite ***,the retained/reversed austenite has beneficial effects on the corrosion resistance and could reduce the sensitivity of stress corrosion cracking for high strength martensite ***,the corrosion mechanisms of additive manufacturing high strength steels and the ideas for designing new high strength martensite steel are explored.

关键词： corrosion behavior high strength martensite steel microstructure additive manufacturing

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Development of Private Higher Education in Macao: Exploring the Relationship between Government and Private Sector

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Frontiers of Education in China 2010年第3期5卷 450-463页

作者： cheng man Diana Lau Pong Kau Yuen Faculty of management and Administration Macao University of Science and TechnologyMacaoChina Center for Pre-university Studies University of MacaoMacaoChina

The development of private higher education in Macao has experien- ced rapid growth in the past two decades. The purpose of this paper is to understand this trend by investigating the facts and figures supplied by official sources and to analyze the role between the Government and the private sector. This paper shows that the attitude of the Macao Government is neither authoritative nor laissez-faire toward private higher education. On the one hand, the Government is investing heavily in the public sector. On the other hand, it is assisting the private sector by various means. However, there is a lack of systematic planning in the area of public-private partnership. There are also two issues which may hinder the current development of private higher education. They are an outdated legal framework and a lack of standardized quality assurance measures.

关键词： private higher education Macao Government legal framework public participation

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Influence of oxide scales on the corrosion behaviors of B510L hot-rolled steel strips

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International Journal of Minerals,Metallurgy and Materials 2016年第7期23卷 769-778页

作者： cheng man Chao-fang Dong Hui-bin Xue Kui Xiao Xiao-gang Li Hui-bin Qi Key Laboratory for Corrosion and Protection(MOE) University of Science and Technology BeijingBeijing 100083China Ningbo Institute of Material Technology and Engineering Chinese Academy of SciencesNingbo 315201China BaoSteel Group Technological Center Shanghai 201900China

The influence of oxide scales on the corrosion behaviors of B510 L hot-rolled steel strips was investigated in this study. Focused ion beams and scanning electron microscopy were used to observe the morphologies of oxide scales on the surface and cross sections of the hot-rolled steel. Raman spectroscopy and X-ray diffraction were used for the phase analysis of the oxide scales and corrosion products. The corrosion potential and impedance were measured by anodic polarization and electrochemical impedance spectroscopy. According to the results, oxide scales on the hot-rolled strips mainly comprise iron and iron oxides. The correlation between mass gain and test time follows a power exponential rule in the damp-heat test. The corrosion products are found to be mainly composed of γ-Fe OOH, Fe3O4, ？-Fe OOH, and γ-Fe2O3. The contents of the corrosion products are different on the surfaces of the steels with and without oxide scales. The steel with oxide scales is found to show a higher corrosion resistance and lower corrosion rate.

关键词： strip steel hot rolling focused ion beams Raman spectroscopy oxide scale corrosion

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Thermotolerant and fireproof gel polymer electrolyte toward high-performance and safe lithium-ion battery

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Journal of Energy Chemistry 2022年第2期31卷 9-18页

作者： man-cheng Long Ting Wang Ping-Hui Duan You Gao Xiu-Li Wang Gang Wu Yu-Zhong Wang The Collaborative Innovation Center for Eco-Friendly and Fire-Safety Polymeric Materials(MoE) National Engineering Laboratory of Eco-Friendly Polymeric Materials(Sichuan)State Key Laboratory of Polymer Materials EngineeringCollege of ChemistrySichuan UniversityChengdu 610064China

Poly(ethylene oxide)(PEO)and its derivatives based gel polymer electrolytes(GPEs)are severely limited in advanced and safe lithium-ion batteries(LIBs)owing to the intrinsically high flammability of liquid electrolytes and *** adding flame retardants to the GPEs can suppress their flammability and thus improve the safety of LIBs,but results in deteriorative electrochemical ***,a novel GPE with chemically bonded flame retardant(*** vinylphosphonate)in cross-linked polyethylene glycol diacrylate matrix,featuring both high-safety and high-performance,is *** as-prepared GPE storing the commercial 1 mol L^(-1) LiPF6 electrolyte resists high temperature of 200℃and cannot be ignited as well as possesses a high ionic conductivity(0.60 m S cm^(-1))and good compatibility with ***,the LiFePO_(4)/Li battery with this GPE delivers a satisfactory capacity of 142.2 m A h g^(-1) and a superior cycling performance with a capacity retention of 96.3%and a coulombic efficiency of close to 100%for 350 cycles at 0.2 C under ambient ***,the battery can achieve steady charge–discharge for 100 cycles with a coulombic efficiency of 99.5%at 1 C under 80℃and run normally even at a high temperature of 150℃or under the exposure to butane *** scanning calorimetry manifests significantly improved battery safety compared to commercial battery *** work provides a new pathway for developing next-generation advanced LIBs with enhanced performance and high safety.

关键词： Gel polymer electrolyte Poly(ethylene oxide) Flame retardant Vinylphosphonate Lithium-ion batteries

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Prediction model for atmospheric corrosion of 7005-T4 aluminum alloy in industrial and marine environments

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International Journal of Minerals,Metallurgy and Materials 2018年第11期25卷 1313-1319页

作者： Xiao-guang Sun Peng Lin cheng man Jian Cui Hai-bo Wang Chao-fang Dong Xiao-gang Li CRRC Qingdao Sifang Co. Ltd. Corrosion and Protection Center University of Science and Technology Beijing

Accelerated corrosion tests of the 7005-T4 aluminum alloy were conducted to determine a suitable service life prediction method by using alternating wet–dry cycles in three kinds of solutions. The morphology and composition analysis of the corrosion product revealed that slight corrosion occurred on the surfaces of the samples immersed in a 0.25 wt% Na_2S_2O_8 solution. However, pitting corrosion occurred on the surfaces of the samples immersed in a 3.5 wt% NaCl solution, whereas exfoliation corrosion occurred on the surfaces of the samples immersed in a mixture of 0.25 wt% Na_2S_2O_8 and 3.5 wt% NaCl solutions. A power exponent relationship was observed between the mass loss and exposure time of the 7005-T4 aluminum alloy immersed in the three kinds of solutions. In the mixture of 0.25 wt% Na_2S_2O_8 and 3.5 wt% NaCl solutions, the mass loss of the aluminum alloy yielded the maximum value. Based on the calculation of the correlation coefficients, the alternating wet–dry procedure in a 3.5 wt% NaCl solution could be used to predict the corrosion behavior of 7005-T4 aluminum alloy exposed in the atmosphere of Qingdao, China. The prediction model is as follows: T = 104.28×t^(0.91), where T is the equivalent time and t is the exposure time.

关键词： aluminum alloy atmospheric corrosion accelerated test correlation coefficient relational model

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