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Local search yields a PTAS for fixed-dimensional k-means problem with penalties

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Journal of the Operations Research Society of China 2024年第2期12卷 351-362页

作者： Fan Yuan Da-Chuan Xu Dong-lei du Dong-Mei Zhang Beijing Institute for Scientific and Engineering Computing Beijing University of TechnologyBeijing 100124China Faculty of Management University of New BrunswickFrederictonNB E3B 9Y2Canada School of Computer Science and Technology Shandong Jianzhu UniversityJinan 250101ShandongChina

We study a problem called the k-means problem with penalties(k-MPWP),which is a natural generalization of the typical k-means *** this problem,we have a set D of client points in R^(d),a set F of possible centers in R^(d),and a penalty cost Pj>O for each point j∈*** are also given an integer k which is the size of the center point *** want to find a center point set S■F with size k,choose a penalized subset of clients P■D,and assign every client in D\P to its open *** goal is to minimize the sum of the squared distances between every point in D\P to its assigned centre point and the sum of the penalty costs for all clients in *** using the multi-swap local search technique and under the fixed-dimensional Euclidean space setting,we present a polynomial-time approximation scheme(PTAS)for the k-MPWP.

关键词： Approximation algorithm k-means Local search Penalty

Stepwise colloidal lithography toward scalable and various planar chiral metamaterials

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Rare Metals 2024年第2期43卷 723-735页

作者： Xiu Yang Yong Liu Fei-Liang Chen Qian-Qi Lin Rohit Chikkaraddy Shan-Shan Huang Shi-Lin Xian Yi-Dong Hou Jing-lei du Liang-Ping Xia Chun-lei du School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu610054China School of Optoelectronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu610054China Zhuhai Multiscale Optoelectronics Technology Co. Ltd.Zhuhai915060China Hybrid Materials for Opto-Electronics Group Department of Molecules and MaterialsMESA+Institute for NanotechnologyMolecules Center and Center for Brain-Inspired Nano SystemsFaculty of Science and TechnologyUniversity of Twente7500 AEEnschedeThe Netherlands School of Physics and Astronomy University of BirminghamBirminghamB152TTUK College of Physics Sichuan UniversityChengdu610065China Key Laboratory of Micro Nano Optoelectronic Devices and Intelligent Perception Systems Yangtze Normal UniversityChongqing408100China

Chiral metamaterials(CMs)composed by artificial chiral resonators have attracted great attentions in the recent decades due to their strong chiroptical resonance and identifiable interaction with chiral materials,facilitating practical applications in chiral biosensing,chiral emission,and display ***,the complex geometry of CMs improves the fabrication difficulty and hinders their scalable fabrication for practical applications,especially in the visible and ultraviolet *** potential strategy is the colloidal lithography that enables parallel fabrication for scalable and various planar ***,we demonstrate a stepwise colloidal lithography technique that uses sequential deposition from multiple CMs and expand their variety and *** geometry and optical chirality of building blocks from single deposition are systematically investigated,and their combination enables a significant extension of the range of chiral patterns by multiple-step *** approach resulted in a myriad of complex designs with different characteristic sizes,compositions,and shapes,which are particularly beneficial for the development of nanophotonic *** addition,we designed a flexible chiral device based on PDMS,which exhibits a good CD value and excellent stability even after multiple inward and outward *** excellent compatibility to various substrates makes the planar CMs more flexible in practical applications in microfluidic biosensing.

关键词： Chiral metamaterials Colloidal lithography Nanophotonics Metasurfaces Plasmonics Nanofabrications Flexible devices

The degradation of cathodic Fe/N/C catalyst in PEMFCs:The evolution of remanent active sites after demetallation

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Journal of Materials Science & Technology 2024年第6期173卷 100-106页

作者： Xiaohua Yang Wentao Sun Jiatang Chen Yang Gao Rongxian Zhang Qun Luo Tao Lyu lei du Institut National de la Recherche Scientifique-Énergie Matériaux et Télécommunications J3X 1P7 VarennesQCCanada School of Chemistry and Chemical Engineering Jiangsu UniversityZhenjiang 212013China State Key Laboratory of Advanced Special Steels&Shanghai Key Laboratory of Advanced Ferrometallurgy School of Materials Science and EngineeringShanghai UniversityShanghai 200444China Huangpu Hydrogen Energy Innovation Center School of Chemistry and Chemical EngineeringGuangzhou UniversityGuangzhou 510006China

The state-of-the-art Fe/N/C catalyst has presented comparable initial cathode performance to the benchmark Pt/C catalyst in proton exchange membrane fuel cells(PEMFCs).However,the major bottleneck is its significant activity decay in real-world PEMFC *** superposed“fast decay”and“slow decay”have been well documented to describe the degradation process of Fe/N/C catalysts during PEMFC *** fast decay has been well understood in close relation to the demetallation at the initial 15-h stability ***,it is still unclear how the remanent active sites evolve after *** this end,the catalyst performance and evolution of a typical Fe/N/C active site were herein investigated through postmortem characterizations of the membrane electrode assemblies(MEAs)after different *** is presented that 1 bar pressure and 80℃ temperature are the optimized conditions for Fe/N/C ***,the“fast decay”in the initial 15 h is immune to the various operating parameters,while the“slow decay”highly depends on the applied temperature and *** to the X-ray absorption spectra(XAS)analysis and stability test of MEA,the gradual evolution of Fe-N coordination to Fe-O is found correlated with the“slow decay”and accounts for the catalyst decay after the demetallation process.

关键词： Fe/N/C Stability Decay mechanism Metal oxidation PEMFCs

Bimetallic NiCoP catalysts anchored on phosphorus-doped lignin-based carbon for robust oxygen evolution performance

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Rare Metals 2024年第7期43卷 3084-3095页

作者： Ling-Ying-Zi Xiong Bo-Wen Liu lei du Yue-Kuan Zhou Xu-Liang Lin Huan Wang Guangdong Engineering Technology Research Center for Sensing Materials&Devices Guangzhou Key Laboratory of Sensing Materials&DevicesSchool of Chemistry and Chemical EngineeringGuangzhou UniversityGuangzhou 510006China School of Chemical Engineering and Light Industry Guangdong University of TechnologyGuangzhou 510006China Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center Jieyang 515200China Sustainable Energy and Environment Thrust Function HubThe Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511400China Division of Emerging Interdisciplinary Areas Department of Mechanical and Aerospace EngineeringThe Hong Kong University of Science and TechnologyHong Kong 999077China State Key Lab of Pulp and Paper Engineering South China University of TechnologyGuangzhou 510640China

Oxygen evolution reaction(OER)catalysts are the key core materials that determine the performance of fuel cells,metal-air batteries,electrolytic water decomposition,and other *** this work,a green lignin-based non-precious metal OER catalyst was prepared by a simple ***,c arboxylated lignin was used to complex Ni and Co in situ,and then they were placed with sodium hypophosphite in the same tube furnace for upstream and downstream high-temperature calcination to construct a lignin carbon-based Ni-Co bimetallic OER catalyst(NiCoP@C).The synthesized catalyst is a porous bimetallic phosphide with a three-dimensional network structure and high-density electrochemical active ***@C exhibited favorable catalytic activity for the oxygen evolution reaction(OER)with overpotential of 280 mV at 10 mA·cm~(-2)and a Tafel slope of 77 mV·dec~(-1).Additionally,it exhibited remarkable durability during *** functional theory(DFT)calculations revealed that by leveraging the distinctive structure of transition metal phosphide nanoparticles incorporated into a reticulated substrate,the NiCoP@C catalyst offered an increased number of active sites for OER catalysis,significantly enhancing its stability during practical *** present study broadens the utilization pathways of biomass to"turn waste into treasure,"aligning the development concept of green sustainable development.

关键词： Oxygen evolution reaction Lignin Carbon-based catalyst Nickel-cobalt bimetal Metal phosphide

Green hydrogen production by intermediate-temperature protonic solid oxide electrolysis cells:Advances,challenges,and perspectives

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InfoMat 2024年第3期6卷 22-65页

作者： Chunmei Tang Yao Yao Ning Wang Xiaohan Zhang Fangyuan Zheng lei du Dongxiang Luo Yoshitaka Aoki Siyu Ye Huangpu Hydrogen Energy Innovation Center School of Chemistry and Chemical EngineeringGuangzhou UniversityGuangzhouthe People's Republic of China Beijing Institute of Metrology Beijingthe People's republic of China Faculty of Engineering Hokkaido UniversitySapporoJapan

Protonic solid oxide electrolysis cells(P-SOECs)operating at intermediate temperatures,which have low costs,low environmental impact,and high theoretical electrolysis efficiency,are considered promising next-generation energy conversion devices for green hydrogen ***,the developments and applications of P-SOECs are restricted by numerous material-and interface-related issues,including carrier mismatch between the anode and electrolyte,current leakage in the electrolyte,poor interfacial contact,and chemical *** the past few decades,considerable attempts have been made to address these issues by improving the properties of *** review comprehensively explores the recent advances in the mechanisms governing steam electrolysis in P-SOECs,optimization strategies,specially designed components,electrochemical performance,and *** particular,given that the lack of suitable anode materials has significantly impeded P-SOEC development,the relationships between the transferred carriers and the cell performance,reaction models,and surface decoration approaches are meticulously ***,the challenges hindering P-SOEC development are discussed and recommendations for future research directions,including theoretical calculations and simulations,structural modification approaches,and large-scale single-cell fabrication,are proposed to stimulate research on P-SOECs and thereby realize efficient electricity-to-hydrogen conversion.

关键词： designed components electrochemical performance hydrogen production key materials protonic solid oxide electrolysis cells

Efficient conversion of aromatic and phenylpropanoid alcohols to acids by the cascade biocatalysis of alcohol and aldehyde dehydrogenases

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Synthetic and Systems Biotechnology 2024年第2期9卷 187-195页

作者： Zetian Qiu Xiaohui Liu Jie Yu Yushuo Zhao Guang-Rong Zhao Shengying Li Kun Liu lei du Li Ma State Key Laboratory of Microbial Technology Shandong UniversityQingdaoShandong266237China Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering(Ministry of Education) School of Chemical Engineering and TechnologyTianjin UniversityYaguan Road 135Jinnan DistrictTianjin300350China School of Health Management Hengxing UniversityQingdaoShandong266100China

Benzyl and phenylpropanoid acids are widely used in organic synthesis of fine chemicals,such as pharmaceuticals and ***,biocatalysis of these acids has received less attention than chemical *** of the main challenges for biological production is the limited availability of alcohol dehydrogenases and aldehyde *** microorganisms are potential sources of these *** this study,129 alcohol dehydrogenases and 42 aldehyde dehydrogenases from Corynebacterium glutamicum,Pseudomonas aeruginosa,and Bacillus subtilis were identified and explored with various benzyl and phenylpropanoid alcohol and aldehyde substrates,among which four alcohol dehydrogenases and four aldehyde dehydrogenases with broad substrate specificity and high catalytic activity were ***,a cascade whole-cell catalytic system including ADH-90,ALDH-40,and the NAD(P)H oxidase LreNox was established,which showed high efficiency in converting cinnamyl alcohol and p-methylbenzyl alcohol into the respective carboxylic ***,this biocatalytic system can be easily scaled up to gram-level production,facilitating preparation purposes.

关键词： Benzyl acids Phenylpropanoid acids Alcohol dehydrogenases Aldehyde dehydrogenases Whole-cell catalysis

Palmitoleic acid on top of HFD ameliorates insulin resistance independent of diacylglycerols and alters gut microbiota in C57BL/6J mice

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Food Science and Human Wellness 2024年第2期13卷 856-868页

作者： Qijian Liang Yan Zheng Fanli Meng Xiaofan Jiang Qingcai Zhen Zhongting Lu Shixiu Zhang lei du Hao Wu Xin Guo Department of Nutrition and Food Hygiene School of Public HealthCheeloo College of MedicineShandong UniversityJinan 250012China Research Center of Translational Medicine Jinan Central Hospital Affiliated to Shandong First Medical UniversityJinan 250013China Department of Hepatology Qilu Hospital of Shandong UniversityJinan 250012China Institute of Hepatology Shandong UniversityJinan 250012China

With the prevalence of obesity and obesity-related metabolic syndrome,such as insulin resistance in recent years,it is urgent to explore effective interventions to prevent the progression of obesity-related metabolic *** acid is a monounsaturated fatty acid that is available from dietary sources,mainly derived from marine products.P almitoleic acid plays a positive role in maintaining glucose homeostasis and reducing ***,it is still unknow the mechanism of palmitoleic acid in ameliorating insulin ***,we investigated the effects of palmitoleic acid on chow diet(CD)-fed and high-fat diet(HFD)-fed mice,which were fed CD or HFD for 12 weeks before *** administrated mice with BSA(control),oleic acid,or palmitoleic acid for 6 weeks on top of CD or HFD *** found that palmitoleic acid only improved glucose homeostasis in HFD-fed obese mice by increasing glucose clearance and reducing *** study explored that palmitoleic acid changed the composition of gut microbiota by decreasing Firmicutes population and increasing Bacteroidetes *** colon,palmitoleic acid increased intestinal tight junction integrity and reduced ***,palmitoleic acid decreased macrophage infiltration in liver and adipose tissue and increase glucose uptake in adipose ***(DAG)in tissue(for example,liver)is found to positively correlated with *** enhanced the levels of DAGs in liver but not in adipose tissue in this *** acid did not reverse the high DAG levels induced by HFD in ***,in HFD-fed mice,palmitoleic acid reduced insulin resistance by an independent-manner of *** might be associated with the beneficial effects of palmitoleic acid on altering the gut microbiota composition,improving of intestinal barrier function,and downregulating the inflammation in colon,liver,and adipose tissue.

关键词： Palmitoleic acid High fat diet Insulin resistance Gut microbiota

Advanced 2D molybdenum disulfide for green hydrogen production: Recent progress and future perspectives

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Frontiers in Energy 2024年第3期18卷 308-329页

作者： Meng FANG Yuqin PENG Puwei WU Huan WANG Lixin XING Ning WANG Chunmei TANG Ling MENG Yuekuan ZHOU lei du Siyu YE Huangpu Hydrogen Energy Innovation Centre School of Chemistry and Chemical EngineeringGuangzhou UniversityGuangzhou 510006China Sustainable Energy and Environment Thrust Function HubThe Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511400China Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and TechnologyHong KongChina SinoHykey Technology Company Ltd. Guangzhou 510760China

The development of renewable and affordable energy is crucial for building a sustainable society. In this context, establishing a sustainable infrastructure for renewable energy requires the integration of energy storage, specifically use of renewable hydrogen. The hydrogen evolution reaction (HER) of electrochemical water splitting is a promising method for producing green hydrogen. Recently, two-dimensional nanomaterials have shown great promise in promoting the HER in terms of both fundamental research and practical applications due to their high specific surface areas and tunable electronic properties. Among them, molybdenum disulfide (MoS2), a non-noble metal catalyst, has emerged as a promising alternative to replace expensive platinum-based catalysts for the HER because MoS_(2)has a high inherent activity, low cost, and abundant reserves. At present, greatly improved activity and stability are urgently needed for MoS_(2)to enable wide deployment of water electrolysis devices. In this regard, efficient strategies for precisely modifying MoS_(2)are of interest. Herein, the progress made with MoS_(2)as an HER catalyst is reviewed, with a focus on modification strategies, including phase engineering, morphology design, defect engineering, heteroatom doping, and heterostructure construction. It is believed that these strategies will be helpful in designing and developing high-performance and low-cost MoS2-based catalysts by lowering the charge transfer barrier, increasing the active site density, and optimizing the surface hydrophilicity. In addition, the challenges of MoS_(2)electrocatalysts and perspectives for future research and development of these catalysts are discussed.

关键词： molybdenum disulfide(MoS_(2)) hydrogen evolution reaction(HER) active site electrocatalyst modification strategie

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3个层面科技协同促进粮食产业的发展

科技导报 2024年第16期42卷 66-71页

作者：杜磊吉林省社会科学院长春130033

保障粮食安全、促进粮食产业发展壮大是建设农业强国、实现乡村振兴的应有之义,而这需要以科学技术为代表的新质生产力的强有力支撑。综述了中国粮食产业科技水平与发达国家和跨国粮商之间存在的差距,以及面临科研资源有限且分散、科研... 详细信息

保障粮食安全、促进粮食产业发展壮大是建设农业强国、实现乡村振兴的应有之义,而这需要以科学技术为代表的新质生产力的强有力支撑。综述了中国粮食产业科技水平与发达国家和跨国粮商之间存在的差距,以及面临科研资源有限且分散、科研成果转化率有待提升、科技成果应用后续服务欠缺等现实。提出应从3个层面促进粮食产业的科技协同,即科技研发的全国层面协同、科技成果应用的省域层面协同和科技服务的县域层面协同。通过3个层面的科技协同,促进现有科研资源的优化组合和成果的高效利用,形成以科技成果加快培育粮食产业新质生产力的体制机制,推进中国农业强国建设和粮食产业高质量发展进程。

关键词：粮食产业科技协同科技研发协同科技成果应用协同科技服务协同