检索结果-南通市图书馆

Higher-order expansions of powered extremes of logarithmic general error distribution

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 47-54页

作者： TAN Xiao-feng li li-hui School of Mathematics and Statistics Southwest UniversityChongqing 400715China

In this paper,Let M_(n)denote the maximum of logarithmic general error distribution with parameter v≥1.Higher-order expansions for distributions of powered extremes M_(n)^(p)are derived under an optimal choice of normalizing constants.It is shown that M_(n)^(p),when v=1,converges to the Frechet extreme value distribution at the rate of 1/n,and if v>1 then M_(n)^(p)converges to the Gumbel extreme value distribution at the rate of(loglogn)^(2)=(log n)^(1-1/v).

关键词： logarithmic general error distribution convergence rate higher-order expansion powered ex-treme

Energy beam-based direct and assisted polishing techniques for diamond:A review

在线全文

学校读者我要写书评

暂无评论

International Journal of Extreme Manufacturing 2024年第1期6卷 93-124页

作者： Zhuo li feng Jiang Zhengyi Jiang Zige Tian Tian Qiu Tao Zhang Qiuling Wen Xizhao Lu jing Lu Hui Huang Institute of Manufacturing Engineering Huaqiao UniversityXiamen 361021People’s Republic of China School of Mechanical MaterialsMechatronic and Biomedical EngineeringUniversity of WollongongWollongongNSW 2522Australia College of Mechanical Engineering and Automation Huaqiao UniversityXiamen 361021People’s Republic of China State Key Laboratory of High Performance Tools Huaqiao UniversityXiamen 361021People’s Republic of China

Diamond is a highly valuable material with diverse industrial applications,particularly in the fields of semiconductor,optics,and high-power electronics.However,its high hardness and chemical stability make it difficult to realize high-efficiency and ultra-low damage machining of diamond.To address these challenges,several polishing methods have been developed for both single crystal diamond(SCD)and polycrystalline diamond(PCD),including mechanical,chemical,laser,and ion beam processing methods.In this review,the characteristics and application scope of various polishing technologies for SCD and PCD are highlighted.Specifically,various energy beam-based direct and assisted polishing technologies,such as laser polishing,ion beam polishing,plasma-assisted polishing,and laser-assisted polishing,are summarized.The current research progress,material removal mechanism,and infuencing factors of each polishing technology are analyzed.Although some of these methods can achieve high material removal rates or reduce surface roughness,no single method can meet all the requirements.Finally,the future development prospects and application directions of different polishing technologies are presented.

关键词： single crystal diamond polycrystalline diamond energy beam polishing technology material removal mechanism influencing factors

Polyoxometalate-organic cage with{Ni_(4)SiW_(9)}node for photocatalytic hydrogen evolution

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第3期35卷 177-181页

作者： jing li Yeqin feng Fangyu Fu Xing Xin Guoyu Yang Hongjin Lv MOE Key Laboratory of Cluster Science Beijing Key Laboratory of Photoelectroic/Electrophotonic Conversion MaterialsSchool of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 102488China

The design and syntheses of metal-organic cages(MOCs)based on polyoxometalates(POMs)building blocks have attracted increasing attention due to their intriguing molecular architectures and physicochemical properties.In this work,we have successfully synthesized and systematically characterized a tetrahedral polyoxometalate-based organic cage(POC),K_(3)Na_(17)H_(12)[(C_(4)H_(6)O_(6))_(6)[Ni_(4)(OH)_(3)(A-α-SiW_(9)O_(34))]_(4)]·96H_(2)O(Ni_(16)L_(6)(SiW_(9))_(4)),using tritopic Ni_(4)-substituted Keggin cluster(Ni_(4)SiW_(9))as nodes and flexible L-(+)-tartaric acid ligands as linkers.The resulting POC tetrahedron has been firstly investigated as efficient catalyst for visible-light-driven hydrogen production,achieving a turnover number of 15,500 after 96-h photocatalysis.Such high catalytic performance of Ni_(16)L_(6)(SiW_(9))_(4)POC catalyst could be attributed to its unique cage structure,thereby offering more efficient catalytic component accessibility.In addition,spectroscopic analyses illustrated the photocatalytic mechanism and the structural stability of the TBA-Ni_(16)L_(6)(SiW_(9))_(4)catalyst during the photocatalytic process.

关键词： Polyoxometalate Polyoxometalate-organic cages Photocatalytic hydrogen production Visible light illumination

Regulation of specific abnormal calcium signals in the hippocampal CA1 and primary cortex M1 alleviates the progression of temporal lobe epilepsy

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2024年第2期19卷 425-433页

作者： feng Chen Xi Dong Zhenhuan Wang Tongrui Wu liangpeng Wei Yuanyuan li Kai Zhang Zengguang Ma Chao Tian jing li jingyu Zhao Wei Zhang Aili liu Hui Shen Laboratory of Neurobiology School of Biomedical EngineeringTianjin Medical UniversityTianjinChina Institute for Translational Neuroscience the Second Affiliated Hospital of Nantong UniversityNantongJiangsu ProvinceChina Institute for Translational Brain Research Fudan UniversityShanghaiChina Department of Radiology the Affiliated Drum Tower Hospital of Nanjing University Medical SchoolNanjingJiangsu ProvinceChina Innovative Institute of Chinese Medicine and Pharmacy Shandong University of Traditional Chinese MedicineJinanChina Department of Anesthesiology Tianjin Medical University General HospitalTianjinChina Department of Orthopaedics Tianjin Medical University General HospitalTianjinChina Tianjin Eye Hospital Tianjin Eye InstituteTianjin Key Lab of Ophthalmology and Visual ScienceTianjinChina Laboratory of Neurobiology School of Basic Medical SciencesTianjin Medical UniversityTianjinChina

Temporal lobe epilepsy is a multifactorial neurological dysfunction syndrome that is refractory,resistant to antiepileptic drugs,and has a high recurrence rate.The pathogenesis of temporal lobe epilepsy is complex and is not fully understood.Intracellular calcium dynamics have been implicated in temporal lobe epilepsy.However,the effect of fluctuating calcium activity in CA1 pyramidal neurons on temporal lobe epilepsy is unknown,and no longitudinal studies have investigated calcium activity in pyramidal neurons in the hippocampal CA1 and primary motor cortex M1 of freely moving mice.In this study,we used a multichannel fiber photometry system to continuously record calcium signals in CA1 and M1 during the temporal lobe epilepsy process.We found that calcium signals varied according to the grade of temporal lobe epilepsy episodes.In particular,cortical spreading depression,which has recently been frequently used to represent the continuously and substantially increased calcium signals,was found to correspond to complex and severe behavioral characteristics of temporal lobe epilepsy ranging from gradeⅡto gradeⅤ.However,vigorous calcium oscillations and highly synchronized calcium signals in CA1 and M1 were strongly related to convulsive motor seizures.Chemogenetic inhibition of pyramidal neurons in CA1 significantly attenuated the amplitudes of the calcium signals corresponding to gradeⅠepisodes.In addition,the latency of cortical spreading depression was prolonged,and the above-mentioned abnormal calcium signals in CA1 and M1 were also significantly reduced.Intriguingly,it was possible to rescue the altered intracellular calcium dynamics.Via simultaneous analysis of calcium signals and epileptic behaviors,we found that the progression of temporal lobe epilepsy was alleviated when specific calcium signals were reduced,and that the end-point behaviors of temporal lobe epilepsy were improved.Our results indicate that the calcium dynamic between CA1 and M1 may reflect specific epileptic behaviors corresponding to diff

关键词： Ca^(2+) calcium signals chemogenetic methods hippocampus primary motor cortex pyramidal neurons temporal lobe epilepsy

A novel predictor of unsustained return of spontaneous circulation in cardiac arrest patients through a combination of capnography and pulse oximetry: a multicenter observational study

在线全文

学校读者我要写书评

暂无评论

World Journal of Emergency Medicine 2024年第1期15卷 16-22页

作者： jing Yang Hanqi Tang Shihuan Shao feng Xu Yangyang Fu Shengyong Xu Chen li Yan li Yang liu Joseph Harold Walline Huadong Zhu Yuguo Chen Xuezhong Yu Jun Xu Emergency Department State Key Laboratory of Complex Severe and Rare DiseasesPeking Union Medical College HospitalChinese Academy of Medical Science and Peking Union Medical CollegeBeijing 100730China Emergency Department Peking University People’s HospitalBeijing 100044China Department of Emergency and Chest Pain Center Shandong Provincial Clinical Research Center for Emergency and Critical Care MedicineKey Laboratory of Emergency and Critical Care Medicine of Shandong ProvinceQilu Hospital of Shandong UniversityJinan 250012China Emergency Department Beijing Jishuitan HospitalBeijing 100035China Emergency Department Tianjin Medical University General HospitalTianjin 300052China Department of Emergency Medicine Penn State Health Milton S.Hershey Medical Center and Penn State College of MedicineHershey 17033USA

BACKGROUND:Unsustained return of spontaneous circulation(ROSC)is a critical barrier to survival in cardiac arrest patients.This study examined whether end-tidal carbon dioxide(ETCO_(2))and pulse oximetry photoplethysmogram(POP)parameters can be used to identify unsustained ROSC.METHODS:We conducted a multicenter observational prospective cohort study of consecutive patients with cardiac arrest from 2013 to 2014.Patients’general information,ETCO_(2),and POP parameters were collected and statistically analyzed.RESULTS:The included 105 ROSC episodes(from 80 cardiac arrest patients)comprised 51 sustained ROSC episodes and 54 unsustained ROSC episodes.The 24-hour survival rate was significantly higher in the sustained ROSC group than in the unsustained ROSC group(29.2%vs.9.4%,P<0.05).The logistic regression analysis showed that the difference between after and before ROSC in ETCO_(2)(ΔETCO_(2))and the difference between after and before ROCS in area under the curve of POP(ΔAUCp)were independently associated with sustained ROSC(odds ratio[OR]=0.931,95%confi dence interval[95%CI]0.881-0.984,P=0.011 and OR=0.998,95%CI 0.997-0.999,P<0.001).The area under the receiver operating characteristic curve ofΔETCO_(2),ΔAUCp,and the combination of both to predict unsustained ROSC were 0.752(95%CI 0.660-0.844),0.883(95%CI 0.818-0.948),and 0.902(95%CI 0.842-0.962),respectively.CONCLUSION:Patients with unsustained ROSC have a poor prognosis.The combination ofΔETCO_(2) andΔAUCp showed signifi cant predictive value for unsustained ROSC.

关键词： Return of spontaneous circulation Pulse oximetry photoplethysmogram End-tidal carbon dioxide Cardiac arrest Cardiopulmonary resuscitation

Activation of NRF2 by celastrol increases antioxidant functions and prevents the progression of osteoarthritis in mice

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Natural Medicines 2024年第2期22卷 137-145页

作者： liU Mingming GUO Jiatian ZHAO jing li Hongye feng Xiaoxiao liU Haojun ZHANG Hao JIA Xuejun WEI Rushuai li Fang CHEN Chong HOU Mingzhuang LV Nanning XU Haiyan Department of human anatomy Xuzhou Medical UniversityXuzhou 221004China Department of Orthopedic Surgery The Affiliated Lianyungang Clinical College of Xuzhou Medical University(The Second People’s Hospital of Lianyungang)Lianyungang 222003China Department of Orthopaedics The First Afliated Hospital of Soochow UniversitySoochow UniversitySuzhou 215006China Institute of Hematology Xuzhou Medical UniversityXuzhou 221004China

Excessive oxidative stress impairs cartilage matrix metabolism balance,significantly contributing to osteoarthritis(OA)development.Celastrol(CSL),a drug derived from Tripterygium wilfordii,has recognized applications in the treatment of cancer and immune system disorders,yet its antioxidative stress mechanisms in OA remain underexplored.This study aimed to substantiate CSL’s chondroprotective effects and unravel its underlying mechanisms.We investigated CSL’s impact on chondrocytes under both normal and inflammatory conditions.In vitro,CSL mitigated interleukin(IL)-1β-induced activation of proteinases and promoted cartilage extracellular matrix(ECM)synthesis.In vivo,intra-articular injection of CSL ameliorated cartilage degeneration and mitigated subchondral bone lesions in OA mice.Mechanistically,it was found that inhibiting nuclear factor erythroid 2-related factor 2(NRF2)abrogated CSL-mediated antioxidative functions and exacerbated the progression of OA.This study is the first to elucidate the role of CSL in the treatment of OA through the activation of NRF2,offering a novel therapeutic avenue for arthritis therapy.

关键词： Osteoarthritis Celastrol Articular cartilage Extracellular matrix NRF2

Transition metal clusters with precise numbers of atoms anchored on graphdiyne as multifunctional electrocatalysts for OER/ORR/HER:a computational study

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第7期43卷 3107-3117页

作者： Xin-Yang liu jing-Wei liu Gang li jing-Xiang Zhao College of Chemistry and Chemical Engineering Harbin Normal University

Subnanometer metal clusters play an increasingly important role in heterogeneous catalysis due to their high catalytic activity and selectivity.In this work,by means of the density functional theory（DFT） calculations,the catalytic activities of transition metal clusters with precise numbers of atoms supported on graphdiyne(TM1-4@GDY,TM=V,Cr,Mn,Fe,Co,Ni,Cu,Ru,Rh,Pd,Ir,Pt) were investigated for oxygen evolution reactions（OER）,oxygen reduction reactions（ORR） and hydrogen evolution reactions（HER）.The computed results reveal that the Pd2,Pd4and Pt1anchored graphdiyne can serve as trifunctional catalysts for OER/ORR/HER with the overpotentials of 0.49/0.37/0.06,0.45/0.33/0.12 and 0.37/0.43/0.01 V,respectively,while Pd1and Pt2@graphdiyne can exhibit excellent catalytic performance for water splitting（OER/HER） with the overpotentials of 0.55/0.17 and 0.43/0.03 V.In addition,Ni1and Pd3anchored GDY can perform as bifunctional catalysts for metal-air cells（OER/ORR） and fuels cells（ORR/HER） with the overpotentials of 0.34/0.32 and 0.42/0.04 V,respectively.Thus,by precisely controlling the numbers of atoms in clusters,the TM1-4anchored graphdiyne can serve as promising multifunctional electrocatalysts for OER/ORR/HER,which may provide an instructive strategy to design catalysts for the energy conversation and storage devices.

关键词： Density functional theory Graphdiyne Single-cluster catalysts Multifunctional electrocatalysts Overpotential

Interfacial Electronic Modulation of Dual-Monodispersed Pt–Ni_(3)S_(2) as Efficacious Bi-Functional Electrocatalysts for Concurrent H_(2) Evolution and Methanol Selective Oxidation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第4期16卷 415-431页

作者： Qianqian Zhao Bin Zhao Xin Long Renfei feng Mohsen Shakouri Alisa Paterson Qunfeng Xiao Yu Zhang Xian‑Zhu Fu jing‑li Luo Shenzhen Key Laboratory of Energy Electrocatalytic Materials Shenzhen Key Laboratory of Polymer Science and TechnologyGuangdong Research Center for Interfacial Engineering of Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen 518060People’s Republic of China Canadian light Source Inc. SaskatoonSK S7N 0X4Canada Instrumental Analysis Center of Shenzhen University(lihu Campus) Shenzhen UniversityShenzhen 518055People’s Republic of China

Constructing the efficacious and applicable bifunctional electrocatalysts and establishing out the mechanisms of organic electro-oxidation by replacing anodic oxygen evolution reaction(OER) are critical to the development of electrochemicallydriven technologies for efficient hydrogen production and avoid CO_(2) emission. Herein, the hetero-nanocrystals between monodispersed Pt(~ 2 nm) and Ni_(3)S_(2)(~ 9.6 nm) are constructed as active electrocatalysts through interfacial electronic modulation, which exhibit superior bi-functional activities for methanol selective oxidation and H_(2) generation. The experimental and theoretical studies reveal that the asymmetrical charge distribution at Pt–Ni_(3)S_(2) could be modulated by the electronic interaction at the interface of dual-monodispersed heterojunctions, which thus promote the adsorption/desorption of the chemical intermediates at the interface. As a result, the selective conversion from CH_(3)OH to formate is accomplished at very low potentials(1.45 V) to attain 100 m A cm^(-2) with high electronic utilization rate(~ 98%) and without CO_(2) emission. Meanwhile, the Pt–Ni_(3)S_(2) can simultaneously exhibit a broad potential window with outstanding stability and large current densities for hydrogen evolution reaction(HER) at the cathode. Further, the excellent bi-functional performance is also indicated in the coupled methanol oxidation reaction(MOR)//HER reactor by only requiring a cell voltage of 1.60 V to achieve a current density of 50 m A cm^(-2) with good reusability.

关键词： Dual-monodispersed heterostructure Electronic interactive modulation Reaction mechanism Methanol oxidation reaction Hydrogen generation

Mechanical property and thermal shock behavior of tungsten-yttria-stabilized zirconia cermet fabricated by spark plasma sintering

在线全文

学校读者我要写书评

暂无评论

Tungsten 2024年第1期6卷 134-140页

作者： lin-Chao Zhang Ke jing Rui liu Zhuo-Ming Xie Jun-feng Yang Gang li Xian-Ping Wang Xue-Bang Wu Qian-feng Fang Chang-Song liu Key Laboratory of Materials Physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China University of Science and Technology of China Hefei 230026China Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of ChinaChengdu 610041China

The cermet fuels have been considered as a potential key component for the nuclear thermal propulsion,and the homogeneity of the fuel particles in the metal matrix plays a crucial role in stabilizing the structure at extremely high temperatures.In this work,liquid paraffin was used as additive to improve the distribution of yttria-stabilized zirconia(YSZ,an appropriate surrogate for UO_(2) fuel)microspheres in the tungsten(W)matrix,and the W-YSZ cermet wafers(volume ratio 1:1)with a relative density of 97.6%were fabricated by spark plasma sintering with a specifically designed program.The effects of the paraffin dosage(0-5 wt.%)on the homogeneity,microstructure,mechanical properties,and the thermal conductivity of W-YSZ cermet were investigated.The W-YSZ sample with 2 wt.%paraffin shows the highest homogeneity and exhibits the best comprehensive properties,including the ultimate tensile strength of 132.2 MPa at 600℃,the bending strength of455 MPa and thermal conductivity of 50 W·m^(-1)·K^(-1)at room temperature.Moreover,the cermet could keep structurally sound after thermal shocked at a heat load of 20 MW·m^(-2).These results would be helpful for the design and optimization of the cermet fuels in the nuclear thermal propulsion.

关键词： Nuclear thermal propulsion Tungsten Cermet liquid paraffin Thermal shock