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Science China Mathematics 2024年

作者： feng shao Institute of Mathematics Academy of Mathematics and Systems ScienceChinese Academy of Sciences School of Mathematical Sciences University of Chinese Academy of Sciences

Let X be an irreducible Hermitian symmetric space of compact type（IHSS for short）. In this paper,we give the irreducible decomposition of SymrTX. As a by-product, we give a cohomological characterization of the rank of X. Moreover, we introduce pseudoeffective thresholds to measure the bigness of tangent bundles of smooth complex projective varieties precisely and calculate them for irreducible Hermitian symmetric spaces of compact type.

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Hotspots and trends of risk factors in gastric cancer: A visualization and bibliometric analysis

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World Journal of Gastrointestinal Oncology 2024年第5期16卷 2200-2218页

作者： Meng Li Ning Gao shao-Li Wang Yu-feng Guo Zhen Liu Department of Gastroenterology Guang'anmen HospitalChina Academy of Chinese Medical SciencesBeijing 100053China Department of Acupuncture and Moxibustion Guang'anmen HospitalChina Academy of Chinese Medical SciencesBeijing 100053China

BACKGROUND The lack of specific symptoms of gastric cancer(GC)causes great challenges in its early diagnosis.Thus it is essential to identify the risk factors for early diagnosis and treatment of GC and to improve the survival rates.AIM To assist physicians in identifying changes in the output of publications and research hotspots related to risk factors for GC,constructing a list of key risk factors,and providing a reference for early identification of patients at high risk for GC.METHODS Research articles on risk factors for GC were searched in the Web of Science core collection,and relevant information was extracted after screening.The literature was analyzed using Microsoft Excel 2019,CiteSpace V,and VOSviewer 1.6.18.RESULTS A total of 2514 papers from 72 countries and 2507 research institutions were retrieved.China(n=1061),National Cancer Center(n=138),and Shoichiro Tsugane(n=36)were the most productive country,institution,or author,respectively.The research hotspots in the study of risk factors for GC are summarized in four areas,namely:Helicobacter pylori(H.pylori)infection,single nucleotide polymorphism,bio-diagnostic markers,and GC risk prediction models.CONCLUSION In this study,we found that H.pylori infection is the most significant risk factor for GC;single-nucleotide polymorphism(SNP)is the most dominant genetic factor for GC;bio-diagnostic markers are the most promising diagnostic modality for GC.GC risk prediction models are the latest current research hotspot.We conclude that the most important risk factors for the development of GC are H.pylori infection,SNP,smoking,diet,and alcohol.

关键词： Gastric cancer Risk factor Bibliometric Research hotspots VOSviewer

Effect of Frequency on Degradation in BOPP Films Under Repetitively Pulsed Voltage

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1280-1290页

作者： Chuansheng Zhang Yu feng Fei Kong Bangdou Huang Cheng Zhang Tao shao Beijing International S&T Cooperation Base for Plasma Science and Energy Conversion Institute of Electrical EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Operating conditions of film capacitors are complex,and the problem of film insulation failure caused by repetitively pulsed voltage is becoming ever serious.Degradation of the film under repetitively pulsed voltage cannot be accurately evaluated by the average breakdown electric field.In this paper,the effects of pulsed electric field and pulse repetition frequency on the breakdown in biaxially oriented polypropylene(BOPP)films are investigated.Three phases of BOPP degradation are proposed based on the voltage amplitude,i.e.,maintenance(M),decline(D),and near-zero(N).Evolution of the BOPP film from degradation to breakdown at different frequencies is presented.Meanwhile,transition of discharge mode and elemental composition of the film are analyzed.Experimental results show continuous heat generation under repetitive microsecond pulses is the dominant factor for degradation of BOPP film.The number of applied pulses and the repetitive stressing time decrease exponentially with increase of frequency.This research can be contributed to the safe and reliable operation of capacitors.

关键词： Aging breakdown film capacitor polypropylene repetitive pulse

Genomic analysis of Nypa fruticans elucidates its intertidal adaptations and early palm evolution

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Journal of Integrative Plant Biology 2024年第4期66卷 824-843页

作者： Weihong Wu Xiao feng Nan Wang shao shao Min Liu Fa Si Linhao Chen Chuanfeng Jin shaohua Xu Zixiao Guo Cairong Zhong Suhua Shi Ziwen He State Key Laboratory of Biocontrol and Guangdong Provincial Key Laboratory of Plant Resources School of Life SciencesSun Yat-sen UniversityGuangzhou 510275China Greater Bay Area Institute of Precision Medicine School of Life SciencesFudan UniversityGuangzhou 511462China Hainan Academy of Forestry(Hainan Academy of Mangrove) Haikou 571100China

Nypa fruticans(Wurmb),a mangrove palm species with origins dating back to the Late Cretaceous period,is a unique species for investigating long-term adaptation strategies to intertidal environments and the early evolution of palms.Here,we present a chromosome-level genome sequence and assembly for N.fruticans.We integrated the genomes of N.fruticans and other palm family members for a comparative genomic analysis,which confirmed that the common ancestor of all palms experienced a whole-genome duplication event around 89 million years ago,shaping the distinctive characteristics observed in this clade.We also inferred a low mutation rate for the N.fruticans genome,which underwent strong purifying selection and evolved slowly,thus contributing to its stability over a long evolutionary period.Moreover,ancient duplicates were preferentially retained,with critical genes having experienced positive selection,enhancing waterlogging tolerance in N.fruticans.Furthermore,we discovered that the pseudogenization of Early Methionine-labelled 1(EM1)and EM6 in N.fruticans underly its crypto-vivipary characteristics,reflecting its intertidal adaptation.Our study provides valuable genomic insights into the evolutionary history,genome stability,and adaptive evolution of the mangrove palm.Our results also shed light on the long-term adaptation of this species and contribute to our understanding of the evolutionary dynamics in the palm family.

关键词： crypto-vivipary genome stability long-term adaptation mangrove Nypa fruticans palm

Understanding the Thermal Impedance of Silicone Rubber/Hexagonal Boron Nitride Composites as Thermal Interface Materials

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Chinese Journal of Polymer Science 2024年第3期42卷 352-363,I0008页

作者： Yuan Ji Shi-Da Han Hong Wu shao-Yun Guo feng-Shun Zhang Jian-Hui Qiu The State Key Laboratory of Polymer Materials Engineering Sichuan Provincial Engineering Laboratory of Plastic/Rubber Complex Processing TechnologyPolymer Research InstituteSichuan UniversityChengdu 610065China Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China Department of Mechanical Engineering Faculty of Systems Science and TechnologyAkita Prefectural UniversityAkita 015-0055Japan

Silicone rubber(SR) composites are most widely used as thermal interface materials(TIMs) for electronics heat dissipation. Thermal impedance as the main bottleneck limiting the performance of TIMs is usually neglected. Herein, the thermal impedance of SR composites loaded with different levels of hexagonal boron nitride(h-BN) as TIMs was elaborated for the first time by the ASTM D 5470 standard test and finite element analysis. It was found that elastic modulus and surface roughness of SR composites increased with the increase of h-BN content, indicating that the conformity was reduced. When the assembly pressure was 0.69 MPa, there existed an optimal h-BN content at which the contact resistance was minimum(0.39 K·cm^(2)·W^(-1)). Although the decreased bond line thickness(BLT) by increasing the assembly pressure was beneficial to reduce the thermal impedance, the proper assembly pressure should be selected to prevent the warpage of the contact surfaces and the increase in contact resistance, according to the compression properties of the SR composites. This study provides valuable insights into fabrication of high-performance TIMs for modern electronic device applications.

关键词： Thermal interface materials Hexagonal boron nitride Thermal impedance Surfaces

Progress in research on metal-based materials in stabilized Zn anodes

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Rare Metals 2024年第1期43卷 20-40页

作者： Le Li shao-feng Jia Ming-Hui Cao Yong-Qiang Ji Heng-Wei Qiu Dan Zhang Shaanxi Key Laboratory of Industrial Automation School of Mechanical EngineeringShaanxi University of TechnologyHanzhong 723001China School of Electronic and Information Engineering Qingdao UniversityQingdao 266071China State Key Laboratory for Artifcial Microstructure and Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China Department of Chemistry Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical BiologyTsinghua UniversityBeijing 100084China Shaanxi Key Laboratory of Catalysis School of Chemistry and Environment ScienceShaanxi University of TechnologyHanzhong 723001China

Aqueous zinc-ion batteries(ZIBs) combine the benefits of metallic Zn anodes with those of aqueous electrolytes and are well suited for large-scale energy storage because of their inherent high safety, cost-effectiveness, and eco-friendliness. Currently, the practical application of such batteries is hindered by the poor cycling performance of Zn anodes due to uncontrolled dendrite formation and severe side reactions, although recent reports suggest that these problems can be mitigated through the modification of Zn anodes with metal-based materials.Given that the mechanisms of improving Zn deposition and the structural evolution of metal-based materials have not been systematically reviewed, we herein systematically overview the metal-based materials used to stabilize Zn anodes, starting with a brief summary of the anode working mechanism and the challenges faced by stabilized Zn anodes. Subsequently, the design principles of Zn anodes stabilized by metal-based materials and the related recent progress are reviewed, and the key challenges and perspectives for the future development of such Zn anodes are proposed.

关键词： Zinc-ion batteries(ZIBs) Zn anode Metalbased materials Alloying metal Stabilized Zn anodes

Influence of self-similar stresses on scenario earthquake construction:An example along the Tanlu Fault

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Science China Earth Sciences 2024年第5期67卷 1687-1697页

作者： feng HU Huajian YAO Houyun YU Zeyu LU Jieyi HOU Song LUO Zhigang shao Xiaofei CHEN School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China Mengcheng Geophysical National Field Scientific Observatory Hefei 230026China Department of Earth and Space Science Southern University of Science and TechnologyShenzhen 518055China Institute of Earthquake Prediction China Earthquake AdministrationBeijing 100036China

As a famous deep and large fault in eastern China,the Tanlu Fault passes through Anhui,Jiangsu,and Shandong and into northeastern China.It is important to improve the understanding of seismic hazard assessments in areas near faults.We start a scenario earthquake simulation in the M7.5 earthquake potential area of the Xinyi-Sihong segment of the Tanlu Fault.The fault rupture length and width are constrained according to the scaling law of large intraplate earthquakes,the background normal stress is depth dependent,and the initial shear stresses are determined using trial and error by matching the earthquake magnitude.Considering the 120 km rupture length of the M7.5 earthquake,we compare the horizontal uniform stress model and self-similar stress perturbation model.Our findings reveal that the seismic source time function of the horizontal uniform stress model is similar to that of the Haskell model and that of the self-similar stress perturbation model is more similar to that of a real earthquake case.We compare the dynamic rupture simulation and ground motion results under four different stress conditions and find that the shorter the characteristic length of the self-similar function is,the rougher the initial stress.For the M7.5earthquake with an epicenter in the vicinity of Suqian,the Xinyi-Tancheng segment,which is located in the IX-intensity zone north of the epicenter,vibrates more strongly on the northern side than on the southern side due to the influence of the lowvelocity zone and the peak slip rate.The response spectra analysis at stations in the study area is useful for improving the earthquake resistance capability.

关键词： Scenario earthquakes Self-similar stress Tanlu Fault Dynamic rupture Ground motion

Highly Conductive Ag/pCF/MVQ Composite Rubber for Efficient Electromagnetic Interference Shielding

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Chinese Journal of Polymer Science 2024年第6期42卷 864-873页

作者： Yang Chen Xiao-Ming shao Liang He Yi-Nuo Xu Qi-Yuan Yao Ding feng Wen-Cai Wang State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical TechnologyBeijing100029China Key Laboratory of Beijing City for Preparation and Processing of Novel Polymer Materials Beijing University of Chemical TechnologyBeijing100029China Sino-german School of Engineering Qingdao University of Science and TechnologyQingdao266400China

In this study,flexible and highly conductive composite rubber at low filler content was successfully prepared through polydopamine-assisted electroless silver plating plus mechanical mixing.Firstly,carbon fibers(CF)were activated by polydopamine(PDA)to improve the surface activity by self-polymerization reaction.Next,because of the metal chelating ability of PDA,silver layer was firmly deposited on the surface of CF through a facile electroless silver plating method.Finally,flexible silver-plated carbon fibers(Ag/pCF)silicone rubber composites prepared by mechanical mixing.By using X-ray photoelectron spectroscopy(XPS)and X-ray diffraction(XRD),the chemical composition and crystal structure of Ag/pCF were examined,and scanning electron microscopy(SEM)was used to assess the surface morphology of the Ag/pCF.The results showed that a uniform and dense silver layer was formed on the surface of the CF,and the conductivity of the Ag/pCF could reach 7885 S/cm.It was noteworthy that the composite rubber filled with only 45 phr Ag/pCF had a high electromagnetic interference shielding effectiveness(100 dB)due to the low density and high aspect ratio of Ag/pCF.The composite rubber has excellent potential for application in the field of electromagnetic interference shielding.

关键词： Carbon fibers Polydopamine Electroless plating Silver Electromagnetic interference shielding

Engineering Shewanella-re duce d graphene oxide aerogel biohybrid to efficiently synthesize Au nanoparticles

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Journal of Materials Science & Technology 2024年第1期168卷 50-61页

作者： Baocai Zhang Shulin shao Huan Yu Qijing Liu Sicheng Shi Qingyuan Wu Zijie Wu Yiyu feng Yifei Wang Xi Sun Deguang Wu feng Li Hao Song Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering(Ministry of Education) Tianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering(Tianjin) School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China School of Materials Science and Engineering Tianjin UniversityTianjin 300350China College of Biological Engineering Tianjin Agricultural UniversityTianjin 300384China Department of Brewing Engineering Moutai InstituteLuban AveRenhuai 564507China

Biosynthesizing Au nanoparticles(AuNPs)from gold-bearing scraps provides a sustainable method to meet the urgent demand for AuNPs.However,it remains challenging to efficiently biosynthesize AuNPs of which the diameter is less than 10 nm from a trace amount of Au^(3+)concentration at the level of tens ppm.Here,we constructed an exoelectrogenic cell(eCell)-conductive reduced-graphene-oxide aero-gel(rGA)biohybrid by assembling Shewanella sp.S1(SS1)as living biocatalyst and rGA as conductive ad-sorbent,in which Au^(3+)at trace concentrations would be enriched by the adsorption of rGA and reduced to AuNPs through the extracellular electron transfer(EET)of SS1.To regulate the size of the synthe-sized AuNPs to 10 nm,the strain SS1 was engineered to enhance its EET,resulting in strain RS2(pYYD-P tac-ribADEHC&pHG13-P_(bad)-omcC in SS1).Strain RS2 was further assembled with rGA to construct the RS2-rGA biohybrid,which could synthesize AuNPs with the size of 7.62±2.82 nm from 60 ppm Au^(3+)so-lution.The eCell-rGA biohybrid integrated Au^(3+)adsorption and reduction,which enabled AuNPs biosyn-thesis from a trace amount of Au^(3+).Thus,the required Au^(3+)ions concentration was reduced by one or two orders of magnitude compared with conventional methods of AuNPs biosynthesis.Our work devel-oped an AuNPs size regulation technology via engineering eCell’s EET with synthetic biology methods,providing a feasible approach to synthesize AuNPs with controllable size from trace level of gold ions.

关键词： Au nanoparticles Exoelectrogenic cell(e-Cell) Shewanella Synthesis biology Extracellular electron transfer Reduced graphene oxide aerogel

The relationship between compartment models and their stochastic counterparts:A comparative study with examples of the COVID-19 epidemic modeling

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Journal of Biomedical Research 2024年第2期38卷 175-188,I0016-I0018页

作者： Ziyu Zhao Yi Zhou Jinxing Guan Yan Yan Jing Zhao Zhihang Peng feng Chen Yang Zhao Fang shao Department of Biostatistics School of Public HealthNanjing Medical UniversityNanjingJiangsu 211166China Nanjing Hanwei Public Health Research Institute Co. LtdNanjingJiangsu 210005China China International Cooperation Center for Environment and Human Health Center for Global HealthNanjing Medical UniversityNanjingJiangsu 211166China The Center of Biomedical Big Data and the Laboratory of Biomedical Big Data Nanjing Medical UniversityNanjingJiangsu 211166China Jiangsu Key Lab of Cancer Biomarkers Prevention and TreatmentCollaborative Innovation Center for Cancer Personalized MedicineNanjing Medical UniversityNanjingJiangsu 211166China

Deterministic compartment models(CMs)and stochastic models,including stochastic CMs and agent-based models,are widely utilized in epidemic modeling.However,the relationship between CMs and their corresponding stochastic models is not well understood.The present study aimed to address this gap by conducting a comparative study using the susceptible,exposed,infectious,and recovered(SEIR)model and its extended CMs from the coronavirus disease 2019 modeling literature.We demonstrated the equivalence of the numerical solution of CMs using the Euler scheme and their stochastic counterparts through theoretical analysis and simulations.Based on this equivalence,we proposed an efficient model calibration method that could replicate the exact solution of CMs in the corresponding stochastic models through parameter adjustment.The advancement in calibration techniques enhanced the accuracy of stochastic modeling in capturing the dynamics of epidemics.However,it should be noted that discrete-time stochastic models cannot perfectly reproduce the exact solution of continuous-time CMs.Additionally,we proposed a new stochastic compartment and agent mixed model as an alternative to agent-based models for large-scale population simulations with a limited number of agents.This model offered a balance between computational efficiency and accuracy.The results of this research contributed to the comparison and unification of deterministic CMs and stochastic models in epidemic modeling.Furthermore,the results had implications for the development of hybrid models that integrated the strengths of both frameworks.Overall,the present study has provided valuable epidemic modeling techniques and their practical applications for understanding and controlling the spread of infectious diseases.

关键词： compartment models agent-based models compartment-agent mixed models comparative study COVID-19