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New strategies for asymmetric photocatalysis: asymmetric organocatalytic/photoredox relay catalysis for efficient synthesis of polycyclic compounds containing vicinal amino alcohols

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Science China Chemistry 2024年第3期67卷 945-952页

作者： Jia-Lu Zhang wen-Bo He Xiu-qin Hu Peng-fei Xu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical EngineeringLanzhou UniversityLanzhou 730000China State Key Laboratory of Veterinary Etiological Biology College of Veterinary MedicineLanzhou UniversityLanzhou Veterinary Research InstituteChinese Academy of Agricultural SciencesLanzhou 730000China MOE Frontiers Science Center for Rare Isotopes Lanzhou UniversityLanzhou 730000China

An asymmetric catalytic strategy in photocatalysis utilizing a chirality-induced approach through an organocatalytic/photoredox relay catalysis strategy is successfully achieved for the rapid construction of polycyclic compounds containing vicinal amino alcohols in a one-pot protocol. This methodology facilitates the efficient synthesis of diverse substituted polycyclic tetrahydroquinoline and benzofuran-derived vicinal amino alcohols, each containing five consecutive chiral centers, with high yields,excellent diastereoselectivities and enantioselectivities(up to 95% yield, >20:1 dr and 98% ee), under mild reaction conditions driven by sequential bifunctional squaramide organocatalyst-catalyzed [4+2] annulation and photocatalyst-catalyzed ketyl radical addition cyclization reaction process. Furthermore, investigations into the stereoselectivity mechanism and high-resolution mass spectrometry(HRMS) experiments on free radical trapping have provided evidence for elucidating the detailed mechanism of chirality-induced processes and chiral intermediate conversions in this procedure.

关键词： enantioselective photocatalysis asymmetric organocatalytic/photocatalysis relay catalysis five consecutive chiral centers chirality-induced strategy chirality vicinal amino alcohols

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An ionic liquid-assisted strategy for enhanced anticorrosion of low-energy PEO coatings on magnesium–lithium alloy

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Journal of Magnesium and Alloys 2024年第6期12卷 2380-2396页

作者： You Zhang Chuping chen Haoyue Tian Shuqi Wang chen wen fei chen College of New Materials and Chemical Engineering Hydrogen Energy Research CentreBeijing Institute of Petrochemical TechnologyBeijing 102617China Key Laboratory of Advanced Structure-Function Integrated Materials and Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China Beijing Spacecrafts China Academy of Space TechnologyBeijing 100190China

A low-energy plasma electrolytic oxidation(LePEO)technique is developed to simultaneously improve energy efficiency and *** liquids(1-butyl-3-methylimidazole tetrafluoroborate(BmimBF_(4)))as sustainable corrosion inhibitors are chosen to investigate the corrosion inhibition behavior of ionic liquid(ILs)during the LePEO process for LA91 magnesium-lithium(Mg-Li)*** show that the ionic liquid BmimBF_(4)participates in the LePEO coating formation process,causing an increment in coating thickness and surface *** low conductivity of the ionic liquid is responsible for the voltage and breakdown voltage increases during the LePEO with IL process(LePEO-IL).After adding BmimBF_(4),corrosion current density decreases from 1.159×10^(−4)A·cm^(−2)to 8.143×10^(−6)A·cm^(−2).The impedance modulus increases to 1.048×10^(4)Ω·cm^(−2)and neutral salt spray remains intact for 24 *** superior corrosion resistance of the LePEO coating assisted by ionic liquid could be mainly attributed to its compact and thick barrier layer and physical absorption of ionic *** ionic liquid-assisted LePEO technique provides a promising approach to reducing energy consumption and improving film performance.

关键词： Magnesium-lithium alloy Plasma electrolytic oxidation Low energy Ionic liquid Corrosion resistance

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A quantum federated learning framework for classical clients

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 1-10页

作者： Yanqi Song Yusen Wu Shengyao Wu Dandan Li Qiaoyan wen Sujuan qin fei Gao State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 00876China Department of Physics The University of Western AustraliaPerthWA 6009Australia School of Computer Science(National Pilot Software Engineering School) Beijing University of Posts and TelecommunicationsBeijing100876China

Quantum federated learning(QFL)enables collaborative training of a quantum machine learning(QML)model among multiple clients possessing quantum computing capabilities,without the need to share their respective local ***,the limited availability of quantum computing resources poses a challenge for each client to acquire quantum computing *** raises a natural question:Can quantum computing capabilities be deployed on the server instead?In this paper,we propose a QFL framework specifically designed for classical clients,referred to as CC-QFL,in response to this *** each iteration,the collaborative training of the QML model is assisted by the shadow tomography technique,eliminating the need for quantum computing capabilities of ***,the server constructs a classical representation of the QML model and transmits it to the *** clients encode their local data onto observables and use this classical representation to calculate local *** local gradients are then utilized to update the parameters of the QML *** evaluate the effectiveness of our framework through extensive numerical simulations using handwritten digit images from the MNIST *** framework provides valuable insights into QFL,particularly in scenarios where quantum computing resources are scarce.

关键词： client server quantum

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Production of Functional Materials Derived from Regenerated Silk Fibroin by Utilizing 3D Printing and Biomimetic Enzyme-induced Mineralization

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Chinese Journal of Polymer Science 2024年第3期42卷 299-310,I0005页

作者： Ni chen fei-Yu Luo Gong-wen Yang Jin-Rong Yao Xin chen Zheng-Zhong Shao State Key Laboratory of Molecular Engineering of Polymers Laboratory of Advanced Materials and Department of Macromolecular ScienceFudan UniversityShanghai 200433China

Critical-sized bone defects, commonly encountered in clinical orthopedic surgery, present a significant challenge. One of the promising solutions is to prepare synthetic bone substitute materials with precise structural control, mechanical compatibility, and enhanced osteogenic induction performance, nevertheless the successful preparation of such materials remains difficult. In this study, a two-step technique,integrating an extrusion-based printing process with biomimetic mineralization induced by alkaline phosphatase(ALP), was developed. Initially,a pre-cured hydrogel of regenerated silk fibroin(RSF) with a small quantity of hydroxypropyl cellulose(HPC) and ALP was prepared through heating the mixed aqueous solution. This pre-cured hydrogel demonstrated thixotropic property and could be directly extruded into predetermined structures through a 3D-printer. Subsequently, the 3D-printed RSF-based materials with ALP underwent biomimetic in situ mineralization in calcium glycerophosphate(Ca-GP) mineralizing solution, utilizing the polymer chains of RSF as templates and ALP as a trigger for cleaving phosphate bonds of Ca-GP. The resulting 3D-printed RSF-mineral composites including hydrogel and sponge possessed adjustable compression modulus of megapascal grade and variable hydroxyapatite content, which could be controlled by manipulating the duration of the mineralization ***, these 3D-printed RSF-mineral composites demonstrated non-cytotoxicity towards rat bone marrow mesenchymal stem cells. Therefore, they may hold great potential for applications involving the replacement of tissues characterized by osteoinductivity and intricate structures.

关键词： Silk protein Alkaline phosphatase Extrusion-based printing Biomineralization

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Applications of single-cell RNA sequencing in spermatogenesis and molecular evolution

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Zoological Research 2024年第3期45卷 575-585页

作者： wen-Bo chen Meng-fei Zhang Fan Yang Jin-Lian Hua College of Veterinary Medicine Shaanxi Centre of Stem Cells Engineering&TechnologyNorthwest A&F UniversityYanglingShaanxi 712100China Key Laboratory of Livestock Biology Northwest A&F UniversityYanglingShaanxi 712100China

Spermatogenic cell heterogeneity is determined by the complex process of spermatogenesis ***,effectively revealing the regulatory mechanisms underlying mammalian spermatogenic cell development and differentiation via traditional methods is *** in technology have led to the emergence of many single-cell transcriptome sequencing protocols,which have partially addressed these *** this review,we detail the principles of 10x Genomics technology and summarize the methods for downstream analysis of single-cell transcriptome sequencing ***,we explore the role of single-cell transcriptome sequencing in revealing the heterogeneity of testicular ecological niche cells,delineating the establishment and disruption of testicular immune homeostasis during human spermatogenesis,investigating abnormal spermatogenesis in humans,and,ultimately,elucidating the molecular evolution of mammalian spermatogenesis.

关键词： Single-cell RNA sequencing(scRNA-seq) Spermatogenesis Molecular evolution Sertoli cell

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Peracetic acid catalytic activation using Co3O4 nanocluster decorated graphitic carbon nitride for cefapirin degradation in water

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Science China Technological Sciences 2024年第10期67卷 3103-3115页

作者： YIN ShiMei GAO YiXuan chen Long LI Fan LIU XiaoNa QI fei LIU wen Beijing Key Lab for Source Control Technology of Water Pollution College of Environmental Science and EngineeringBeijing Forestry University Key Laboratory of Water and Sediment Sciences (Ministry of Education) College of Environmental Sciences and EngineeringPeking University School of Environmental Science and Engineering Taiyuan University of Technology State Environmental Protection Key Laboratory of All Material Fluxes in River Ecosystems Peking University Beijing National Laboratory for Molecular Sciences Peking University

This study innovated cobalt-based catalytic nanocomposites（CCNs） for the heterogeneous activation of peracetic acid（PAA）,a green and efficient advanced oxidation process for removing antibiotics from *** Co3O4catalysts exhibit limited activity due to stable electronic *** overcome this,CCNs were synthesized using a one-step condensation method,incorporating a size control strategy that anchors Co3O4nanoclusters within 4-5 nm onto six-fold cavity of g-C3N4,simultaneously modifying the coordination environment of *** alteration significantly enhances the adsorption energy of PAA and catalytic activity compared to commercial *** improved performance of CCN2,in particular,is attributed to a shift in the cobalt d band center towards the Fermi level,facilitating electron delocalization and transfer,enhancing Co-O bonding,and accelerating PAA ***2's superior activity,with a cefapirin（CFP） degradation kinetic rate constant(k1=0.760 min-1)～11 times that of PAA direct oxidation(k1=0.070 min-1) and～5 times that of commercial Co3O4/PAA system(k1=0.164 min-1),is due to its ability to generate dominant reactive species for antibiotic degradation,including alkoxy radicals(CH3C（=O）OO·),high valence metal(CoⅣ（=O）2+),and singlet oxygen（1O2）,with the latter two being crucial for the degradation *** degradation of CFP involved three mechanisms,including direct oxidation by PAA,decarboxylation,and open-ring reactions at nitrogen *** research provides insights into developing high-activity catalysts for efficient PAA activation and antibiotic removal,leveraging the strategy of shifting the transition metal d band center.

关键词： peracetic acid Co3O4 nanocluster high valence metal singlet oxygen cefapirin

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Construction of electron rich Fe active sites by FeCu alloy anchoring on carbon nitride for photocatalytic nitrogen reduction

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Rare Metals 2024年第4期43卷 1570-1579页

作者： Gang Dong Cong Huang fei-Yang chen Xue-qin Liu Zhen Li Xiao-Li Su Tao Zeng Yun-Xia chen Yi-Huang chen Yang Wang School of Materials Science and Engineering Jingdezhen Ceramic UniversityJingdezhen333403China Faculty of Materials Science and Chemistry China University of GeosciencesWuhan430074China College of Chemistry and Materials Engineering Wenzhou UniversityWenzhou325035China

Given the clean and inexhaustible solar energy from solar light,photocatalytic ammonia synthesis is extremely ***,high electron-hole recombination rates and insufficient active sites severely limited N2 photoreaction ***,we designed and fabricated FeCu alloy nanoparticles anchored on carbon nitride nanosheets with excellent photocatalyt ic ammonia synthesis *** a coupler between Fe and carbon nitride,Cu promotes the separation of photogenerated charge carriers in carbon nitride under solar light irradiation,and renters the semiconductor a forceful electron donor for the Fe active *** accumulated electrons at Fe sites furtherly facilitated the adsorption and activation of the molecular ***,the uniform dispersed FeCu alloy nanoparticles were on carbon nitride nanosheets enhanced the stability of photocataly tic nitrogen reduction reaction,making the artificial photocataly tic ammonia synthesis more sustainable for *** work highlights that a direct electron transfer channel can be used to regulate the photochemical nitrogen fixation network.

关键词： Photocatalytic N_2 fixation Carbon nitride FeCu alloy Active sites Hydrogenation pathway

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On the Normalized Laplacian Spectral Radius of Traceable Graphs

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Journal of Mathematical Research with Applications 2024年第3期44卷 291-303页

作者： Yafei ZHANG fei wen Yonglei chen Institute of Applied Mathematics Lanzhou Jiaotong University

In this paper, we give some sufficient conditions for a graph to be traceable in terms of its order and size. As applications, the normalized Laplacian spectral conditions for a graph to be traceable are established.

关键词： traceable graphs normalized Laplacian spectral radius degree sequence

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Solidification behaviour and hot cracking susceptibility of a novel Ni-based superalloy

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Journal of Iron and Steel Research International 2024年第4期31卷 956-966页

作者： Yue chen Shao-min Lv Xing-fei Xie Xiao-can wen Jng-long Qu Jin-hui Du High-Temperature Materials Institute China Iron and Steel Research Institute Group Co.Ltd.Beijing 100081China Beijing GAONA Materials and Technology Co. Ltd.Beijing 100081China Sichuan CISRI-GAONA Forging Co. Ltd.Deyang 610000SichuanChina

A novel Ni-based superalloy GH4151,with a γ′ volume fraction of about 55%and a service temperature capability up to 8oo oC,was *** to the different cooling conditions of various regions during the solidification of ingots,significant cooling rate variations may lead to the occurrence of hot *** scanning laser microscope was utilised to investigate the solidification process and phase precipitation behaviour of the GH4151 under wide range cooling *** characteristics of L→γ transformation were analysed,and the growth rates of at each stage were *** segregation behaviour was predicted using the Scheil equation,and the predicted results match well with the experimental *** sensitivity coefficient for hot cracking was modified,and cracking sensitivity coefficient values for the alloy under different cooling rates were computed,revealing that the alloy is most susceptible to hot cracking at 10℃/min cooling ***,controlling the cooling rate can reduce the possibility of hot cracking in ingot.

关键词： Ni-based superalloy Solidification behaviour In-situ observation Clyne and Davies's criterion:Hot cracking susceptibility

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Role of micro-Ca/In alloying in tailoring the microstructural characteristics and discharge performance of dilute Mg-Bi-Sn-based alloys as anodes for Mg-air batteries

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Journal of Magnesium and Alloys 2024年第1期12卷 251-266页

作者： fei-er Shangguan Wei-li cheng Yu-hang chen Ze-qin Cui Hui Yu Hong-xia Wang Li-fei Wang Hang Li Hua Hou School of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China School of Materials Science and Engineering Hebei University of TechnologyTianjin 300132China School of Materials Science and Engineering North University of ChinaTaiyuan 030051China

The influence of micro-Ca/In alloying on the microstructural charac teristics,electrochemical behaviors and discharge properties of extruded dilute Mg-0.5Bi-0.5Sn-based(wt.%)alloys as anodes for Mg-air batteries are *** grain size and texture intensity of the Mg-Bi-Sn-based alloys are significantly decreased after the Ca/In alloying,particularly for the In-containing *** that,in addition to nanoscale Mg_(3)Bi_(2)phase,a new microscale Mg_(2)Bi_(2)Ca phase forms in the Ca-containing *** electrochemical test results demonstrate that Ca/In micro-alloying can enhance the electrochemical *** In to alloy the Mg-Bi-Sn-based alloy is effective in restricting the cathodic hydrogen evolution(CHE)kinetics,leading to a low self-corrosion rate,while severe CHE occurred after Ca *** micro-alloying of Ca/In to Mg-Bi-Sn-based alloy strongly deteriorates the compactness of discharge products film and mitigates the"chunk effect"(CE),hence the cell voltage,anodic efficiency as well as discharge capacity are greatly *** In-containing alloy exhibits outstanding discharge performance under the combined effect of the modified microstructure and discharge products,thus making it a potential anode material for primary Mg-air battery.

关键词： Mg-air batteries Mg-Bi-Sn based alloys Electrochemical behaviors Discharge properties

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