检索结果-南通市图书馆

Local resonance metamaterial-based integrated design for suppressing longitudinal and transverse waves in fluid-conveying pipes

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第10期45卷 1821-1840页

作者： Donghai HAN Qi jia yuanyu gao Qiduo JIN Xin FANG Jihong WEN Dianlong yu Laboratory of Science and Technology on Integrated Logistics Support National University of Defense TechnologyChangsha 410073China College of Intelligence Science and Technology National University of Defense TechnologyChangsha 410073China

To solve the problem of low broadband multi-directional vibration control of fluid-conveying pipes,a novel metamaterial periodic structure with multi-directional wide bandgaps is ***,an integrated design method is proposed for the longitudinal and transverse wave control of fluid-conveying pipes,and a novel periodic structure unit model is constructed for vibration *** on the bandgap vibration reduction mechanism of the acoustic metamaterial periodic structure,the material parameters,structural parameters,and the arrangement interval of the periodic structure unit are *** finite element method(FEM)is used to predict the vibration transmission characteristics of the fluid-conveying pipe installed with the vibration reduction periodic ***,the wave/spectrum element method(WSEM)and experimental test are used to verify the calculated results ***,the vibration attenuation characteristics of the structure under different conditions,such as rubber material parameters,mass ring material,and fluid-structure coupling effect,are *** results show that the structure can produce a complete bandgap of 46 Hz-75 Hz in the low-frequency band below 100 Hz,which can effectively suppress the low broadband vibration of the fluidconveying *** addition,a high damping rubber material is used in the design of the periodic structure unit,which realizes the effective suppression of each formant peak of the pipe,and improves the vibration reduction effect of the fluid-conveying ***,the structure has the effect of suppressing both bending vibration and longitudinal vibration,and effectively inhibits the transmission of transverse waves and longitudinal waves in the *** research results provide a reference for the application of acoustic metamaterials in the multi-directional vibration control of fluid-conveying pipes.

关键词： fluid-conveying pipe acoustic metamaterial multi-directional vibration reduction local resonance

Isotropic negative thermal expansion and its mechanism in tetracyanidoborate salt CuB(CN)_(4)

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第6期31卷 99-103页

作者： Chunyan Wang Qilong gao Andrea Sanson and yu jia Key Laboratory of Materials Physics of Ministry of Education International Laboratory for Quantum Functional Materials of Henanand School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052China Key Laboratory of Special Functional Materials of Ministry of Education and School of Materials Science and EngineeringHenan UniversityKaifeng 475004China Key Laboratory for Quantum Materials and Center for Topological Functional Materials Henan UniversityKaifeng 475004China Department of Physics and Astronomy University of PadovaPadova I-35131Italy

The control of thermal expansion is essential in applications where thermal stability is required from fiber optics coatings,high performance fuel cell cathodes to tooth *** thermal expansion(NTE)materials,although rare,are fundamental for this *** work focuses on studying tetracyanidoborate salt CuB(CN)_(4),an interesting cubicstructure material that displays large isotropic NTE.A joint study of synchrotron x-ray diffraction,temperature-dependent Raman spectroscopy,and lattice dynamics calculations was conducted,showing that not only low-frequency optical modes(transverse thermal vibrations of N and C atoms)but also the acoustic modes(the vibrations of Cu atoms as a collective torsion of the neighboring atoms),contribute to *** a result,new insights were gained into the NTE mechanism of CuB(CN)_(4) and related framework materials.

关键词： negative thermal expansion Prussian blue analogues crystal structure phonons

Plasmonic nanostructures acting as a light-driven O_(2)-sensitive nitroreductase mimic for enhanced photochemical oxidation of para-aminothiophenol

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第11期16卷 12697-12705页

作者： Xinshuang gao jia-jia Zheng Hanbo Li Rui Cai Xingfa gao Xiaochun Wu CAS Key Laboratory of Standardization and Measurement for Nanotechnology National Center for Nanoscience and TechnologyBeijing 100190China Laboratory of Theoretical and Computational Nanoscience National Center for Nanoscience and TechnologyBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Nanozymes,as a novel form of enzyme mimics,have garnered considerable *** overcoming the main disadvantages of their natural analogs,they still face challenges such as restricted mimic types and low substrate ***,we introduce a reactive ligand modification strategy to diversify enzyme mimic ***,we have utilized helical plasmonic nanorods(HPNRs)modified with para-nitrothiophenol(4-NTP)to create an oxygen-sensitive nitroreductase(NTR)with *** act as a light-adjustable source of nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate(NAD(P)H),providing photon-generated energetic electrons to adsorbed 4-NTP *** the presence of O_(2),the activated 4-NTP transfers the captured electron to the adsorbed O_(2),mimicking the electron transfer process in its natural *** enhanced O_(2)activation notably boosts the oxidative coupling of para-aminothiophenol(4-ATP).Density functional theory(DFT)calculations reveal that hot electrons injected into the lowest unoccupied molecular orbital(LUMO)energy level of 4-NTP can be transferred to that of molecular *** conclusion,our findings underline the potential of the reactive ligand modification strategy in developing new types of enzyme reactions,which opens up promising avenues for the enhancement and diversification of nanozyme functionalities.

关键词： plasmonic nanostructure nanozyme nitroreductase para-nitrothiolphenol hot electron injection para-aminothiolphenol

Ultrafine SnO_(2)in situ modified graphite felt derived from metal-organic framework as a superior electrode for vanadium redox flow battery

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 2023年第4期42卷 1214-1226页

作者： Qing-Chun jiang Jin Li yu-Jie Yang yu-Jie Ren Lei Dai jia-Yi gao Ling Wang jia-Ye Ye Zhang-Xing He School of Chemical Engineering North China University of Science and TechnologyTangshan063009China Hebei Province Key Laboratory of Photocatalytic and Electrocatalytic Materials for Environment North China University of Science and TechnologyTangshan063009China Faculty of Science School of Chemistry and PhysicsQueensland University of TechnologyBrisbaneQLD4001Australia Center for Materials Science Queensland University of TechnologyBrisbaneQLD4001Australia

Metal-organic framework(MOF)and its derivatives have low-cost,controllable structure,and good catalytic performance,which are often used in the electrochemical *** this work,SnO_(2)in situ modified graphite felt(SnO_(2)/GF)is prepared by hydrothermal method then simple thermal treatment using Sn-based MOF(Sn-MOF)as ***_(2)is uniformly and firmly distributed on the GF surface rather than the common agglomeration and poor bonding of metal oxides on carbon-based electrodes,providing stable active centers for the VO^(2+)/VO_(2)^(+)and V^(2+)/V^(3+)redox ***250 mA·cm^(-2),the energy efficiency of the battery with SnO_(2)/GF remains at 63.2%,while the blank one has *** former battery,at 100 mA·cm^(-2),has higher energy efficiency and good cycle stability(over 200 cycles).The battery performance of this study is better than that of most previous report in metal oxide-related *** work obtains high-performance composite electrode by simple treatment of MOF,which provides a reference for the application of MOF in vanadium redox flow battery.

关键词： Vanadium redox flow battery(VRFB) Composite electrode Metal-organic framework(MOF) In situ SnO_(2)

Spherical modification of tungsten oxide powder and its mechanism analysis

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2015年第3期34卷 183-188页

作者： Cong-Cong Wang Cheng-Chang jia Peng gao Guo-Cheng Gai yu-Fen Yang School of Materials Science and Engineering University of Science and Technology Beijing Powder Technology R&D Group Department of Material Science and EngineeringTsinghua University

Owing to its high production costs, complexity of equipment, and difficulty in controlling parameters, spherical or subglobose tungsten powder preparation method cannot meet the demand of industrial production. Tungstic oxide powder was treated by particle composite system and its effects were studied. Morphologies of par- ticles were investigated by scanning electron microscopy （SEM）. Particle size analysis was carried out and the related mechanism was discussed. The results show that the processing effect is best when the rotational speed is set at 4,000 ***-1 for 15 rain： the powder particles become nearly spherical and their sharp edge angles are rounded off and reshaped. When the processing time is 60 min, the powders smash to pieces because of too much energy inputting. So the test results, such as grain size distribution, can be explained well. Nearly spherical tungsten powder is obtained after reduction at 780 ℃ for 2 h and its flow ability is significantly improved.

关键词： Nearly spherical tungsten powder Grain size Modification Particle composite system

在线全文

学校读者我要写书评

暂无评论

巴西龟代谢性骨病CT诊断病例报告

动物医学进展 2025年第1期46卷 141-144页

作者：孙嘉徐甘靖宇江蓝刘波俞峰中国农业大学北京100193

代谢性骨病(MBD)是一种因钙缺乏或维生素D 3摄入不足引起的骨骼代谢障碍疾病,其临床表现为骨折、脊椎异常、难产、脱垂等症状。计算机断层扫描(CT)在兽医临床中应用的逐渐增加为龟、鳖类MBD提供了新的诊断方式。该病例中红耳巴西龟血检... 详细信息

代谢性骨病(MBD)是一种因钙缺乏或维生素D 3摄入不足引起的骨骼代谢障碍疾病,其临床表现为骨折、脊椎异常、难产、脱垂等症状。计算机断层扫描(CT)在兽医临床中应用的逐渐增加为龟、鳖类MBD提供了新的诊断方式。该病例中红耳巴西龟血检结果提示其肾脏、肝脏功能损害,钙磷代谢异常。CT扫查提示患龟全身组织大面积矿化、背甲凹陷,定量测量患龟背椎骨、神经骨和胸膜骨3处的骨骼密度远低于正常龟,诊断患龟有严重的MBD。治疗方案为对症治疗、改善饲养管理条件,同时对该龟补充维生素D 3。该病例报告系统陈述了龟鳖MBD的诊疗流程,同时表明了CT扫查可为龟鳖MBD精确诊断、治疗和预后提供新的参考。

关键词：龟代谢性骨病计算机断层扫描骨密度

Homotopy Method for Inverse Design of the Bulbous Bow of A Container Ship

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2017年第1期31卷 98-102页

作者： HUANG yu-jia FENG Bai-wei HOU Guo-xiang gao Liang XIAO Mi School of Naval Architecture and Ocean Engineering Huazhong University of Science and Technology Wuhan 430074 China Key Laboratory of High Performance Ship Technology of Ministry of Education Wuhan University of Technology Wuhan 430063 China State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and Technology Wuhan 430074 China

The homotopy method is utilized in the present inverse hull design problem to minimize the wave-making coefficient of a 1300 TEU container ship with a bulbous bow. Moreover, in order to improve the computational efficiency of the algorithm, a properly smooth function is employed to update the homotopy parameter during iteration. Numerical results show that the homotopy method has been successfully applied in the inverse design of the ship hull. This method has an advantage of high performance on convergence and it is credible and valuable for engineering practice.

关键词： Container iteration inverse utilized properly minimize container valuable Marquardt consuming

Photophysical properties of nitrogen-doped carbon quantum dots synthesized by graphite

在线全文

学校读者我要写书评

暂无评论

Journal of Materiomics 2024年第4期10卷 828-836页

作者： jia Liu Hailong yu Guan Wang Shuang Yang Meichen Li Xin Zhang Yang jia Yachen gao School of Electronic Engineering Heilongjiang UniversityHarbin150080HeilongjiangChina College of Communication and Electronic Engineering Qiqihar UniversityQiqihar161000HeilongjiangChina

Here,nitrogen-doped carbon quantum dots(N-CQDs)were successfully synthesized by the solvothermal method using graphite as the carbon source and N,N-dimethylformamide as the nitrogen *** characterized the structure and chemical constitution of N-CQDs using X-ray diffraction,Fourier transform infrared spectroscopy and X-ray photoelectron *** investigated the pump-and temperature-dependent photoluminescence(PL)properties and the dynamic exciton recombination processes of N-CQDs,using both steady-state and time-resolved PL *** spectral results show that the PL emission peak located at 518 nm at room temperature,mainly originates from the n-π∗transition on the surface of *** pump fluence and PL integral intensity were analyzed to demonstrate the existence of single-photon excitation under the 405 nm laser *** the temperature increases,the non-radiative transition gradually increases,which decreases the PL intensity,the full width at half maxima first narrows and then widens and the PL lifetime gradually ***,we combined the N-CQDs with chip to prepare light-emitting diode(LED).The resulting chromaticity coordinate was obtained to be(0.29,0.40).This study offers a comprehensive understanding of the luminescence mechanism in N-doped CQDs and introduces a novel approach for the quickly fabrication of full-color display LEDs.

关键词： Carbon quantum dots Nitrogen-doped Photoluminescence Temperature-dependent Non-radiative transition

ent-Pimarane Diterpenoid Dimers from Sigesbeckia glabrescens with Potent Anti-inflammatory Activities

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

Chinese Journal of Chemistry 2021年第12期39卷 3315-3321页

作者： Xiao-Xu gao Ying-Ying Zheng Xiao-yu Zhang gao-Sheng Hu Jing-Ming jia An-Hua Wang School of Traditional Chinese Materia Medica Shenyang Pharmaceutical UniversityShenyangLiaoning 110016China

Chromatographic purification of Sigesbeckia glabrescens extracts led to three undescribed ent-pimarane diterpenoid dimers,named glabreside A—C(1-3).Their structures were confirmed by comprehensive spectroscopic analyses,and the structures of compound 1 and 3 were confirmed by X-ray *** results of anti-inflammatory activity assay showed that glabreside C(3)exhibited the most potent inhibition activity on nitric oxide(NO)production induced by lipopolysaccharide(LPS)in BV2 microglia compared with the other two *** C also increased the protein expression level of heme oxygenase-1(HO-1),and suppressed inducible nitric oxide synthase(iNOS)and cyclooxygenase 2(COX2)in LPS-stimulated BV2 ***,glabreside C exerts its anti-inflammatory effect by inhibiting AKT/MAPKs signaling *** findings indicate the vital role of ent-pimarane diterpenoid dimers in explaining the anti-inflammatory activity of *** and provide important evidence for further development and utilization of Sigesbeckiae *** results also suggest that glabreside C is a potential lead compound for anti-inflammatory drugs.

关键词： Siegesbeckia glabrescens Makino Terpenoids Biosynthesis Inflammatory Biological activity