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Post lithium-sulfur battery era:challenges and opportunities towards practical application

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Science China Chemistry 2024年第1期67卷 106-121页

作者： Jiahang chen yang Zhang jun yang Yanna Nuli Jiulin Wang State Key Laboratory of Chemistry and Utilization of Carbon-Based Energy Resources College of ChemistryXinjiang UniversityUrumqi 830046China Department of Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Lithium-sulfur(Li-S)batteries have been regarded as a promising next-generation energy storage system owing to the high theoretical energy density and natural abundance of sulfur.Abundant fundamental researches have pushed the flourishing development on electrochemical behaviors in recent 20 years.It is time to evolve into post-Li-S battery era with the pursuit towards practical application.During the landmark leap,numerous new challenges appear under harsh conditions,such as high sulfur loading,low cathode density,lean electrolyte and limited lithium reservoir.Herein,we summarize the considerable parameters of pouch Li-S cells and review the pioneering studies focused on the cathode structure,conversion kinetics,electrode interphase and battery safety.The interwoven relationship of these key points is concluded and discussed,which provides guidance to future researches aiming to safe and long-lifespan Li-S batteries with high energy density.

关键词： lithium-sulfur batteries practical application harsh conditions energy density pouch cells

Recent Advances in Deciphering the Mechanisms and Biological Functions of DNA Demethylation

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Chinese Journal of Chemistry 2024年第6期42卷 645-651页

作者： yang Feng Sheng-jun chen Bi-Feng Yuan Key Laboratory of Aquatic Product Processing Ministry of Agriculture and Rural AffairsNational R&D Center for Aquatic Product ProcessingSouth China Sea Fisheries Research InstituteChinese Academy of Fishery SciencesGuangzhouGuangdong510300 China School of Public Health Research Center of Public HealthRenmin Hospital of Wuhan UniversityWuhan UniversityWuhanHubei430071 China

5-Methylcytosine (5mC) is a dynamic and reversible epigenetic modification in genomic DNA of higher eukaryotes.It has been well-established that the demethylation of 5mC occurs through the ten-eleven translocation (TET)-mediated oxidation of 5mC followed by thymine DNA glycosylase (TDG)-initiated base excision repair (BER).Recent findings also have identified an alternative pathway of DNA demethylation.In this pathway,TET enzymes directly oxidize 5mC to form 5-formylcytosine (5fC) or 5-carboxylcytosine (5caC).These modified bases can undergo direct deformylation or decarboxylation,respectively.Additionally,DNA demethylation can also occur through the deamination of 5mC and 5hmC,resulting in the production of thymine and 5-hydroxymethyluracil (5hmU),respectively.Various DNA demethylation pathways possess critical functional implications and roles in biological processes.This Recent Advances article will focus on the studies of mechanisms and biological functions of DNA demethylation,shedding light on the reversible nature of the epigenetic modification of 5mC.

关键词： Epigenetics DNA DNA methylation 5-Methylcytosine Demethylation Mechanisms Biological functions C—C bond cleavage Mass spectrometry

Remarkable Wear Resistance in a Complex Concentrated Alloy with Nanohierarchical Architecture and Composition Undulation

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Research 2024年第1期2023卷 403-416页

作者： Yushan Geng Wenyuan chen Hui Tan jun cheng Shengyu Zhu jun yang Weimin Liu State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000PR China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049PR China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 264000PR China

Sustained wear damages on the sliding surfaces of alloys are generally the culprit responsible for the failure of various mechanical systems.Inspired by high-entropy effects,here we deliberately deploy nanohierarchical architecture with composition undulation in a Ni50(AlNbTiV)_(50) complex concentrated alloy,which yields ultralow wear rate within the order of 10^(−7) to 10^(−6) mm^(3)/Nm between room temperature and 800℃.Such remarkable wear resistance heretofore represents one of the highest wear resistance reported for the bulk alloys or composites,and originates from the multi-type adaptive friction interface protection governed by intrinsically nano-coupled grains and nanoprecipitates.This cooperative heterostructure releases gradient frictional stress in stages upon wear at room temperature through the coexistence of multiple deformation pathways while activating a dense nanocrystalline glaze layer upon wear at 800℃ to minimize adhesive and oxidative wear.Our work uncovers a practical avenue for tailoring wear properties with multicomponent heterostructures over a wide temperature range.

关键词： wear alloys friction

Metal-Free Synthesis of 2-Aminobenzothiazoles via I2-Catalyzed Tandem Cyclization Reaction of Amines and Carbon Disulfide

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Chinese Journal of Chemistry 2024年第8期42卷 846-852页

作者： Ting chen Wei Feng Ruitong yang Shanping chen Guo-jun Deng Key Laboratory for Green Organic Synthesis and Application of Hunan Province Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of EducationCollege of ChemistryXiangtan UniversityXiangtanHunan411105 China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiangHunan453007 China

Comprehensive Summary,A convenient approach for the construction of 2-aminobenzothiazoles via I2-catalyzed tandem cyclization reaction of amines and carbon disulfide has been developed.The present approach starts from simple and readily available starting materials,affording a series of 2-aminobenzothiazoles in up to 89%yields under metal-free conditions.In this work,C—H/N—H functionalization was achieved and multiple C-hetero bonds were successfully constructed in one pot.

关键词： Sulfur heterocycles C-H functionalization Cyclization Tandem reaction Transition-metal-free Amines lodine N-Heterocycles

Durable dual-state duplex Si-HfO_(2)with excellent oxidation and cracking resistance

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Journal of Advanced Ceramics 2024年第3期13卷 388-401页

作者： Lin chen Jing-Chuan Luo Wen-Qi yang Chang-Jiu Li Guan-jun yang State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China Xi’an Aerospace Engine Company Limited in CASC Xi’an 710065China

The lifetime of Si bond coatings in environmental barrier coatings is constrained by phase-transition-induced cracking of the SiO_(2)scale.In this study,Si-HfO_(2)dual-state duplex composite materials are proposed to address this issue by partially forming HfSiO_(4)and minimizing the SiO_(2)content.The as-prepared composite exhibited a structure comprising discrete HfO_(2)“bricks”embedded in a continuous Si“mortar”,while the oxidized state transformed into discrete HfSiO_(4)“bricks”within continuous thin SiO_(2)“mortars”.The results indicate that continuous thin SiO_(2)contributes to reducing the oxidation rate to a level comparable to that of pure Si,and discrete HfSiO_(4)particles aid in relieving phase transition-induced stress and inhibiting crack propagation,thereby enhancing oxidation and cracking resistance simultaneously.Consequently,the composite with 20 mol%HfO_(2)and a mean particle size of~500 nm at 1370℃exhibited a service lifetime 10 times greater than that of pure Si.This research provides valuable insights for designing Si-based bond coatings with improved service lifetime.

关键词： oxidation environmental barrier coatings(EBCs) phase transition cracking bond coatings

Sensing Matrix Optimization for Random Stepped-Frequency Signal Based on Two-Dimensional Ambiguity Function

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Chinese Journal of Electronics 2024年第1期33卷 161-174页

作者： Mingjiu LYU Hao chen jun yang Xia WU Ming ZHOU Xiaoyan MA Radar NCO School Air Force Early Warning Academy Department of Early Warning Technology Air Force Early Warning Academy

Compressive sensing technique has been widely applied to achieve range-Doppler reconstruction of high frequency radar by utilizing sparse random stepped-frequency(SRSF) signal, which can suppress the complex electromagnetic interference and greatly reduce the coherent processing interval. An important way to improve the performance of sparse signal reconstruction is to optimize the sensing matrix(SM). However, the existing research on the SM optimization needs to design a measurement matrix with superior performance, which needs a large amount of computation and does not consider the influence of the waveform parameters design. In order to improve the superior reconstruction performance, a novel SM optimization approach for SRSF signal is proposed by using two-dimensional ambiguity function(TDAF) in this paper. Firstly, based on the two-dimensional sparse reconstruction model of the SRSFs, the internal relationship between the waveform parameters and the SM was derived. Secondly, the SM optimization problem was directly transformed into the waveform design of SRSFs. Furthermore, on the basis of analyzing the relationship between the mutual coherence matrix of SM and the TDAF matrix of SRSFs, the purpose of optimizing the SM can be achieved by designing the TDAF of the SRSFs. Based on this analysis, a sparse waveform optimization method with joint constraints of maximum and mean sidelobes of the TDAF by using the genetic algorithm was derived. Compared with the traditional SM optimization method, our method not only avoids generating a new measurement matrix, but also further reduces the complexity of the waveform optimization. Simulation experiments verified the effectiveness of the proposed method.

关键词： Sparse random stepped-frequency signal Two-dimensional ambiguity function Waveform design Compressed sensing Sensing matrix optimization

Experimental and numerical investigation of the impacts of rotor tip-rake on excitation forces of pump-jet propulsors

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Journal of Hydrodynamics 2024年第1期36卷 142-157页

作者： Xue-qin Ji Xiao-song Zhang chen-jun yang Xiao-qian Dong State Key Laboratory of Ocean Engineering Marine Numerical Experiment CentreSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China CSSC Shanghai Marine Energy Saving Technology Co. Ltd.Shanghai200011China China Ship Scientific Research Center Shanghai Branch Shanghai200011China

The tip-clearance flow in a pump-jet propulsor exerts great impacts on the fluctuating pressures and resultant unsteady forces,which are important sources of structural vibrations and radiated noise underwater.The blade geometry close to the tip is an important factor determining the vortex strength in the tip-clearance flow.In the open-water condition,the effects of raking the rotor tips on the duct-surface fluctuating pressures and the resultant unsteady forces acting on different components of the propulsor are investigated via physical model experiments and the numerical solution of Reynolds-averaged Navier-Stokes(RANS)equations coupled with the SST k-ωturbulence model.The measured and simulated results of hydrodynamic pressures are consistent to each other,and the simulated flows help better understand why the fluctuating pressures change with the tip geometry.The strong fluctuations of duct-surface pressures are caused by intensive tip separation vortices.The duct-surface pressure fluctuations are effectively reduced by using the rake distribution near the tip towards blade back side and,for the combination of the five-bladed rotor and the seven-bladed stator,the resultant unsteady horizontal(and vertical)forces acting on the duct and stator are also reduced;while increasing rake leads to negative effect on pressure fluctuations and unsteady horizontal(and vertical)forces acting on all the components of the propulsor.

关键词： Pump-jet tip-clearance tip-rake fluctuating pressures excitation forces

Causal roles of gut microbiota in cholangiocarcinoma etiology suggested by genetic study

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World Journal of Gastrointestinal Oncology 2024年第4期16卷 1319-1333页

作者： Zhi-Tao chen chen-chen Ding Kai-Lei chen yang-jun Gu Chi-cheng Lu Qi-Yong Li Division of Hepatobiliary and Pancreatic Surgery Shulan(Hangzhou)Hospital Affiliated to Zhejiang Shuren University Shulan International Medical CollegeHangzhou 310000Zhejiang ProvinceChina Pediatric Psychology The Affiliated Mental Health Centre&Hangzhou Seventh People’s HospitalZhejiang University School of MedicineHangzhou 310000Zhejiang ProvinceChina School of Medicine Zhejiang Shuren UniversityHangzhou 310000Zhejiang ProvinceChina School of Medicine Zhejiang Chinese Medical University Zhejiang Shuren CollegeHangzhou 310000Zhejiang ProvinceChina

BACKGROUND Cholangiocarcinoma(CCA)is a highly malignant biliary tract cancer with poor prognosis.Previous studies have implicated the gut microbiota in CCA,but evidence for causal mechanisms is lacking.AIM To investigate the causal relationship between gut microbiota and CCA risk.METHODS We performed a two-sample mendelian randomization study to evaluate potential causal associations between gut microbiota and CCA risk using genome-wide association study summary statistics for 196 gut microbial taxa and CCA.Genetic variants were used as instrumental variables.Multiple sensitivity analyses assessed result robustness.RESULTS Fifteen gut microbial taxa showed significant causal associations with CCA risk.Higher genetically predicted abundance of genus Eubacteriumnodatum group,genus Ruminococcustorques group,genus Coprococcus,genus Dorea,and phylum Actinobacteria were associated with reduced risk of gallbladder cancer and extrahepatic CCA.Increased intrahepatic CCA risk was associated with higher abundance of family Veillonellaceae,genus Alistipes,order Enterobacteriales,and phylum Firmicutes.Protective effects against CCA were suggested for genus Collinsella,genus Eisenbergiella,genus Anaerostipes,genus Paraprevotella,genus Parasutterella,and phylum Verrucomicrobia.Sensitivity analyses indicated these findings were reliable without pleiotropy.CONCLUSION This pioneering study provides novel evidence that specific gut microbiota may play causal roles in CCA risk.Further experimental validation of these candidate microbes is warranted to consolidate causality and mechanisms.

关键词： Cholangiocarcinoma Mendelian randomization Gut microbiota Instrumental variables Sensitivity analyses

Investigating the causal associations between five anthropometric indicators and nonalcoholic fatty liver disease:Mendelian randomization study

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World Journal of Clinical Cases 2024年第7期12卷 1215-1226页

作者： Xian-Pei Xiao Yong-jun Dai Yu Zhang Meng yang Jian Xie Guo chen Zheng-jun yang Department of Oncology Luojiang District People's Hospital of Deyang CityDeyang 618000Sichuan ProvinceChina Department of Orthopaedics Luojiang District People's Hospital of Deyang CityDeyang 618000Sichuan ProvinceChina Department of Infectious Diseases Hospital of Chengdu University of Traditional Chinese MedicalChengdu 610500Sichuan ProvinceChina

BACKGROUND Although the etiology of nonalcoholic fatty liver disease(NAFLD)has not been thoroughly understood,the emerging roles of anthropometric indicators in assessing and predicting the risk of NAFLD have been highlighted by accumulating evidence.AIM To evaluate the causal relationships between five anthropometric indicators and NAFLD employing Mendelian randomization(MR)design.METHODS The Anthropometric Consortium provided genetic exposure data for five anthropometric indicators,including hip circumference(HC),waist circumference(WC),waist-to-hip ratio(WHR),body mass index(BMI),and body fat percentage(BF).Genetic outcome data for NAFLD were obtained from the United Kingdom Biobank and FinnGen Consortium.Genome-wide significant single nucleotide polymorphisms were chosen as instrumental variables.Univariable MR(UVMR)and multivariable MR(MVMR)designs with analytical approaches,including inverse variance weighted(IVW),MR-Egger,weighted median(WM),and weighted mode methods,were used to assess the causal relationships between anthropometric indicators and NAFLD.RESULTS Causal relationships were revealed by UVMR,indicating that a higher risk of NAFLD was associated with a perunit increase in WC[IVW:odds ratio(OR)=2.67,95%CI:1.42-5.02,P=2.25×10^(−3)],and BF was causally associated with an increased risk of NAFLD(WM:OR=2.23,95%CI:1.07-4.66,P=0.033).The presence of causal effects of WC on the decreased risk of NAFLD was supported by MVMR after adjusting for BMI and smoking.However,no causal association between BF and NAFLD was observed.In addition,other causal relationships of HC,WHR(BMI adjusted),and BMI with the risk of NAFLD were not retained after FDR correction.CONCLUSION This study establishes a causal relationship,indicating that an increase in WC is associated with a higher risk of NAFLD.This demonstrates that a suitable decrease in WC is advantageous for preventing NAFLD.

关键词： Anthropometric indicator Waist circumference Nonalcoholic fatty liver disease Mendelian randomization Genetic variant