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To improve robustness of mechanical properties of semi-solid cast A356 alloy using taguchi design method

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China Foundry 2024年第2期21卷 175-184页

作者： yi-wu Xu Hong-yi Zhan Wei Tong Jin-ping Li Le-peng Zhang De-jiang Li Xiao-qin zeng School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China China Science Lab General Motors Global Research&DevelopmentShanghai 201206China General Motors(China)Investment Co. Ltd.Shanghai 201206China China International Intellectech Corporation(CIIC) Beijing 100004China

Mechanical properties of semi-solid casting are dependent on multiple processing parameters,and improper processing parameters will not only reduce mean data but also increase *** present study investigated the impact of parameters in slurry preparation and heat treatment on the yield strength and ductility of T6 heat-treated A356 Al-Si alloy using rapid slurry forming(RSF)semi-solid *** focus was primarily on the robustness of mechanical properties based on Taguchi design *** analyzing signal-to-noise ratio and minimum value calculated from-3S,the optimum slurry preparation parameters and heat treatment parameters were determined to be no quench,enthalpy exchange material(EEM)temperature of 140℃,EEM-to-melt ratio of 6mass%,stirring time of 18 s,solution heat treated at 520℃ for 2 h,and ageing heat treated at 190℃ for 6 *** a small batch validation,the-3S yield strength and-3S elongation reach 256.1 MPa and 5.03% respectively,showing a satisfactory *** hardness and microstructure of heat-treated samples with the best and worst properties were characterized to gain insight into the underlying mechanisms affecting the mean value and variations of mechanical properties.

关键词： semi-solid casting taguchi design method signal-to-noise ratio mechanical property microstructure

Aggregation-regulated bioreduction process of graphene oxide by Shewanella bacteria

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Chinese Journal of Chemical Engineering 2024年第5期69卷 56-62页

作者： Kaixin Han yibo zeng yinghua Lu ping zeng Liang Shen Department of Chemical and Biochemical Engineering College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen UniversityXiamen 361005China Chinese Research Academy of Environmental Sciences Beijing 100012China

The bioreduction of graphene oxide(GO)using environmentally functional bacteria such as Shewanella represents a green approach to produce reduced graphene oxide(rGO).This process differs from the chemical reduction that involves instantaneous molecular *** bioreduction,the contact of bacterial cells and GO is considered the rate-limiting *** reveal how the bacteria-GO integration regulates rGO production,the comparative experiments of GO and three Shewanella strains were carried ***-transform infrared spectroscopy,X-ray photoelectron spectroscopy,Raman spectroscopy,and atomic force microscopy were used to characterize the reduction degree and the aggregation *** results showed that a spontaneous aggregation of GO and Shewanella into the condensed entity occurred within 36 h.A positive linear correlation was established,linking three indexes of the aggregation potential,the bacterial reduction ability,and the reduction degree(ID/IG)comprehensively.

关键词： Graphene oxide Reduced graphene oxide Bioreduction Aggregation Shewanella

Lung imaging characteristics in a patient infected with Elizabethkingia miricola following cerebral hemorrhage surgery: A case report

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World Journal of Clinical Cases 2024年第1期12卷 169-175页

作者： ping-Qiang Qi yi-Jun zeng Wei Peng Juan Kuai Department of Neurosurgery The Third Affiliated Hospital of Chengdu Medical College Pidu District People’s HospitalChengdu 611730Sichuan ProvinceChina

BACKGROUND Elizabethkingia miricola is a non-fermenting gram-negative bacterium,which was first isolated from the condensate of the Russian peace space station in *** studies on this bacterium have been carried out in the laboratory,and clinical case studies are *** date,a total of 6 clinical cases have been reported *** SUMMARY We present the first case of postoperative pulmonary infection in a patient with intracerebral hemorrhage due to Elizabethkingia *** imaging character-istics of pulmonary infection were identified and the formulation and selection of the clinical treatment plan for this patient are *** Elizabethkingia miricola infection is *** pulmonary infection occurs,computed tomography imaging may show diffuse distribution of a ground glass density shadow in both lungs,the air containing bronchial sign in local areas,thickening of bronchial vascular bundle,and pleural effusion.

关键词： Elizabethkingia miricola Cerebral hemorrhage surgery Postoperative pulmonary infection Imaging features Case report

Optimal Cooperative Secondary Control for Islanded DC Microgrids via a Fully Actuated Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 405-417页

作者： yi Yu Guo-ping Liu yi Huang Peng Shi IEEE Shenzhen Key Laboratory of Control Theory and Intelligent Systems Southern University of Science and TechnologyShenzhen 518055China School of Electrical Engineering and Automation Wuhan UniversityWuhan 430072China School of Electrical and Mechanical Engineering the University of AdelaideSA 5005Australia Research and Innovation Centre Obuda University1034 BudapestHungary

DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately portray the electrical characteristics of actual MGs while is controller design-friendly has kept the issue active. To this end, this paper establishes a large-signal model containing the comprehensive dynamical behavior of the DC MGs based on the theory of high-order fully actuated systems, and proposes distributed optimal control based on this. The proposed secondary control method can achieve the two goals of voltage recovery and current sharing for multi-bus DC MGs. Additionally, the simple structure of the proposed approach is similar to one based on droop control, which allows this control technique to be easily implemented in a variety of modern microgrids with different configurations. In contrast to existing studies, the process of controller design in this paper is closely tied to the actual dynamics of the MGs. It is a prominent feature that enables engineers to customize the performance metrics of the system. In addition, the analysis of the stability of the closed-loop DC microgrid system, as well as the optimality and consensus of current sharing are given. Finally, a scaled-down solar and battery-based microgrid prototype with maximum power point tracking controller is developed in the laboratory to experimentally test the efficacy of the proposed control method.

关键词： DC microgrids distributed control high-order fully actuated system approach linear quadratic regulator microgrid modeling secondary control

The critical role of energetic fluctuations in charge separation for efficient molecular doping of organic semiconductors

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Science China Chemistry 2024年第11期67卷 3675-3680页

作者： Yan zeng Guangchao Han Yuanping yi Beijing National Laboratory for Molecular Sciences CAS Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

Molecular doping is essential to improve the electrical conductivity of organic semiconductors for high-performance organic electronic devices. However, the doping efficiency is influenced by several factors, such as the energy levels, energetic fluctuations, dielectric properties, and molecular packing structures of the doped films, and the underlying mechanisms for highefficiency doping are still unclear. Here, through multi-level theoretical simulations on a series of fullerene derivatives, we identify that the energetic fluctuations can play a decisive role in activating charge separation for molecular doping. In particular,the doping efficiency appears to be exponentially increased with the fluctuation of charge polarization energies. Therefore,although the charge mobility is somewhat decreased, the experimental electrical conductivity is improved with the increased energetic fluctuation. Moreover, it has been found that polarization energy fluctuation can be effectively enhanced by simply introducing side chains with greater flexibility into organic semiconductors. This article paves the way towards high-efficiency molecular doping of organic semiconductors.

关键词： doping efficiency polarization energies energetic fluctuations organic semiconductors

Studies on the Interaction of DNA and Ru(1,10-phenanthroline)_2-(dipyrido[3,2-a:2′,3′-c]phenazine)^(2+)

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Wuhan University Journal of Natural Sciences 1999年第4期4卷 482-486页

作者： LING Lian sheng, HE Zhi ke,ZHANG ping yi,zeng Yun e College of Chemistry and Enviromental Science, Wuhan University, Wuhan, 430072,China

The interaction of Ru(phen) 2(dppz) 2+ (phen=1,10 phenanthroline,dppz=dipyrido[3,2 a:2′,3′ c]phenazine) and the calfthymus DNA were studied with fluorescence and ultraviolet visible absorption spectroscopy. The ultraviolet visible absorption spectrum of Ru(phen) 2(dppz) 2+ , calfthymus DNA, and their interaction demonstrated that Ru(phen) 2(dppz) 2+ intercalated into the double helix of DNA via the ligand dppz. Fe(CN) 6 4- and NaCl can not quench the fluorescence of Ru(phen) 2(dppz) 2+ DNA, which was in agreement with the intercalation mode.

关键词： Ru(phen) 2(dppz) 2+ DNA absorption spectroscopy fluorescence intercalate binding

Transmissibility of COVID-19 in 11 major cities in China and its association with temperature and humidity in Beijing, Shanghai, Guangzhou, and Chengdu

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Infectious Diseases of Poverty 2020年第4期9卷 150-150页

作者： Xiao-Jing Guo Hui Zhang yi-ping zeng Institute of Public Safety Research Tsinghua UniversityBeijing100084People’s Republic of China

Background The new coronavirus disease COVID-19 began in December 2019 and has spread rapidly by human-to-human *** study evaluated the transmissibility of the infectious disease and analyzed its association with temperature and humidity to study the propagation pattern of *** In this study,we revised the reported data in Wuhan based on several assumptions to estimate the actual number of confirmed cases considering that perhaps not all cases could be detected and reported in the complex situation *** we used the equation derived from the Susceptible-Exposed-Infectious-Recovered(SEIR)model to calculate R0 from January 24,2020 to February 13,2020 in 11 major cities in China for *** the calculation results,we conducted correlation analysis and regression analysis between R0 and temperature and humidity for four major cities in China to see the association between the transmissibility of COVID-19 and the weather *** It was estimated that the cumulative number of confirmed cases had exceeded 45000 by February 13,2020 in *** average R0 in Wuhan was 2.7,significantly higher than those in other cities ranging from 1.8 to *** inflection points in the cities outside Hubei Province were between January 30,2020 and February 3,2020,while there had not been an obvious downward trend of R0 in Wuhan.R0 negatively correlated with both temperature and humidity,which was significant at the 0.01 *** The transmissibility of COVID-19 was strong and importance should be attached to the intervention of its transmission especially in *** to the correlation between R0 and weather,the spread of disease will be suppressed as the weather warms.

关键词： COVID-19 Transmissibility Basic reproduction number Temperature Humidity

Effects of formal credit on pastoral household expense: Evidence from the Qinghai-Xizang Plateau of China

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Journal of Integrative Agriculture 2024年第5期23卷 1774-1785页

作者： Yan Zhang yi Huang Fan Zhang zeng Tang State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems College of Pastoral Agriculture Science and TechnologyLanzhou UniversityLanzhou 730020China

Formal credit is critical in agricultural production,allowing more expenditure and productive input,thereby improving farmers'*** pastoral China,formal financial institutions are gradually ***,a limited understanding remains of how formal credit affects herders'household *** on a survey of 544 herders from the Qinghai-Xizang Plateau of China,this study adopted the propensity score matching approach to identify the effect of formal credit on herders'total household expenses,daily expenses,and productive *** results found that average age,grassland mortgage,and other variables significantly affected herders'participation in formal *** credit could significantly improve household expenses,especially productive expenses.A heterogeneity analysis showed that formal credit had a greater impact on the household total expense for those at higher levels of wealth;however,it significantly affected the productive expense of herders at lower wealth ***,the mediating effect indicated that formal credit could affect herders'household income,thus influencing their household ***,this study suggests that policies should improve herders'accessibility to formal credit.

关键词： formal credit herders expense Qinghai-Xizang Plateau

Optimal proportioning of iron ore in sintering process based on improved multi-objective beluga whale optimisation algorithm

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Journal of Iron and Steel Research International 2024年第7期31卷 1597-1609页

作者： Zong-ping Li Xu-dong Li Xue-tong Yan Wu Wen Xiao-xin zeng Rong-jia Zhu Ya-hui Wang Ling-zhi yi Zhongye Changtian International Engineering Co. Ltd.Changsha 410205HunanChina College of Automation and Electronic Information Xiangtan UniversityXiangtan 411105HunanChina College of Electrical and Information Engineering Hunan UniversityChangsha 410082HunanChina

Proportioning is an important part of sintering,as it affects the cost of sintering and the quality of sintered *** address the problems posed by the complex raw material information and numerous constraints in the sintering process,a multi-objective optimisation model for sintering proportioning was established,which takes the proportioning cost and TFe as the optimisation ***,an improved multi-objective beluga whale optimisation(IMOBWO)algorithm was proposed to solve the nonlinear,multi-constrained multi-objective optimisation *** algorithm uses the con-strained non-dominance criterion to deal with the constraint problem in the ***,the algorithm employs an opposite learning strategy and a population guidance mechanism based on angular competition and two-population competition strategy to enhance convergence and population *** actual proportioning of a steel plant indicates that the IMOBWO algorithm applied to the ore proportioning process has good convergence and obtains the uniformly distributed Pareto ***,compared with the actual proportioning scheme,the proportioning cost is reduced by 4.3361¥/t,and the TFe content in the mixture is increased by 0.0367%in the optimal compromise ***,the proposed method effectively balances the cost and total iron,facilitating the comprehensive utilisation of sintered iron ore resources while ensuring quality assurance.

关键词： Sintering process Proportioning Iron ore Multi-objective beluga whale optimisation algorithm Proportioning cost