检索结果-南通市图书馆

Journal of materials Science & Technology 2022年第35期130卷 86-92页

作者： Xinran ma Yuping Duan Lingxi Huang ben ma Hao Lei Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian 116085China

In the electronic information and intelligent era, microwave absorption materials have been focused on the issue of electromagnetic(EM) pollution, but high-performance absorbers with thin thickness are highly desirable. The positive action between structural design and component selection can be regarded as a function to optimize the microwave loss capacity, which contributes to understanding the response mechanisms from the micro and macro. Therefore, we designed the absorber with quasiperiodic structures of Penrose tiling that has finely engineered the location of maximum absorption peak, the spherical carbonyl iron in thin rhombus, and flakey carbonyl iron in fat rhombus, the effective absorption bandwidth(Reflection Loss ≤ –10 d B) was realized from 6.46 GHz to 15.78 GHz in the 2 mm thickness. The unique arrangement of Penrose tiling can respond alternatingly to EM waves at large scales, and multicomponent coupling is distinctly in the neighboring unit cells. In addition, spraying aluminum pigment as the upper layer, the infrared emissivity is less than 0.35 to meet the complex application *** work opens up novel ideas on quasiperiodic structure combined multicomponent and injects infinite vitality to provide prospects for broadband responsive and high-efciency EM absorbers.

关键词： Microwave absorber Penrose tiling Carbonyl iron Localized coupling

Synthesis and Properties of Perfluorinated Alkyl Silicone Oil Modified Epoxy Resin

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(materials Science) 2014年第2期29卷 361-366页

作者：孙明慧 ma ben 翁睿 School of materials Science and Engineering Wuhan University of Technology

Perfluorinated alkyl silicone oil （PFASO） was successfully synthesized from N-ethyl-N- hydroxylethyl perfluorinated octane sulfonamide, succinie anhydride and amino silicone oil by esterification and amide reaction at moderate temperature in the presence of different catalysts. The chemical structure of the synthesized samples was characterized by Fourier transform infrared spectroscopy （FT-IR）, the relative molecular mass（MM） and molecular mass distribution（MMD） of PFASO were tested by gel filtration chromatography（GFC）. A commercial epoxy resin （DGEBA） was modified with PFASO, with the content of PFASO 1-5 phr. Thermo-gravimetric analysis （TGA）, impact tests, scanning electron microscope （SEM） and water contact angle test were applied to provide accurate results on the thermal stability, toughness and hydrophobicity of PFASO/epoxy complex. The experimental results reveal that epoxy resins can be successfully modified by adding a small amount of as-synthesized modifiers via simple direct mixing, and verify that the as-synthesized modifier can improve the toughness and hydrophobicity of epoxy resin without sacrificing its thermal properties.

关键词： perfluorinated alkyl silicone oil epoxy resin modification

Effect of Electric Field on the Electron-Surface Optical Phonon Scattering Rates in Quantum Wires

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1996年第4期13卷 297-300页

作者： CHANG Kai WANG Ruo-zhen ma ben-kun Department of Physics Beijing Normal UniversityBeijing 100875

By using the variational method and the dielectric continuum model,we investigate the effect of electric Held on the intrasubband scattering rates of electron-surface optical *** results show that the scattering rates tend to increase with the electric field *** scattering rates become significant for wide quantum well wire and sufficiently high fields.

关键词： strength. Electron variational

Three-dimensionally interconnected Co9S8/MWCNTs composite cathode host for lithium–sulfur batteries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2020年第7期29卷 22-29,I0002页

作者： Shengyu Zhao Xiaohui Tian Yingke Zhou ben ma Angulakshmi Natarajan The State Key Laboratory of Refractories and Metallurgy Institute of Advanced Materials and NanotechnologyCollege of Materials and MetallurgyWuhan University of Science and TechnologyWuhan 430081 HubeiChina

Several challenging issues,such as the poor conductivity of sulfur,shuttle effects,large volume change of cathode,and the dendritic lithium in anode,have led to the low utilization of sulfur and hampered the commercialization of lithium–sulfur *** this study,a novel three-dimensionally interconnected network structure comprising Co9 S8 and multiwalled carbon nanotubes(MWCNTs)was synthesized by a solvothermal route and used as the sulfur *** assembled batteries delivered a specific capacity of1154 m Ah g-1 at 0.1 C,and the retention was 64%after 400 cycles at 0.5 *** polar and catalytic Co9 S8 nanoparticles have a strong adsorbent effect for polysulfide,which can effectively reduce the shuttling ***,the three-dimensionally interconnected CNT networks improve the overall conductivity and increase the contact with the electrolyte,thus enhancing the transport of electrons and Li *** adsorption is greatly increased with the synergistic effect of polar Co9 S8 and MWCNTs in the three-dimensionally interconnected composites,which contributes to their promising performance for the lithium–sulfur batteries.

关键词： Three-dimensional network structure MWCNTs Polar and catalytic Co9S8 Lithium–sulfur batteries

Atmospheric Excitation of Time Variable Length-of-Day on Seasonal Scales

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Astronomy and Astrophysics 2006年第1期6卷 120-124页

作者： Li-Hua ma Yan-ben Han National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

We use the method of wavelet transform to analyze the time series of the Earth＇s rotation rate of the EOP （IERS） C04. The result shows that the seasonal （annual and semiannual） variation of the length-of-day （LOD） has temporal variability in its period length and amplitude. During 1965.0-2001.0, the periods of the semiannual and annual components varied mainly from 175-day to 190-day and from 360-day to 370-day, respectively; while their amplitudes varied by more than 0.2 ms and 0.1 ms, respectively. Analyzing the axial component of atmospheric angular momentum （AAM） during this period, we have found that time-variations of period lengths and amplitudes also exist in the seasonal oscillations of the axial AAM and are in good consistency with those of the seasonal LOD change. The time variation of the axial AAM can explain largely the change of the LOD on seasonal scales.

关键词： Earth rotation -- seasonal variation -- wavelet transform

Biogeographic distribution patterns of algal community in different urban lakes in China: Insights into the dynamics and co-existence

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2021年第2期33卷 216-227页

作者： Haihan Zhang Rongrong Zong Huiyan He Kaiwen Liu Miaomiao Yan Yutian Miao ben ma Xin Huang Key Laboratory of Northwest Water Resource Enuironment and EcologyMOEXi'an University of Architecture and TechnologyXi'an 710055China Shaanxi Key Laboratory of Environmental Engineering Xi'an University of Architecture and TechnologyXi'an 710055China

Urban lake ecosystems are significant for social development,but currently we know little about the geographical distribution of algal community in urban lakes at a *** this study,we investigated the algal community structure in different areas of urban lakes in China and evaluated the influence of water quality parameters and geographical location on the algal *** results showed that obvious differences in water quality and algal communities were observed among urban lakes in different geographical *** was the dominant phylum,followed by cyanobacteria in all *** network analysis indicated that algal community composition in urban lakes of the western and southern area showed more variations than the eastern and northern areas,*** analysis and structural equation model revealed that nutrients and p H were dominant environmental factors that affected the algal community,and they showed higher influence than that of iron,manganese and COD Mn ***,algal community and density exhibited longitude and latitude *** general,these results provided an ecological insight into large-scale geographical distributions of algal community in urban lakes,thereby having potential applications for management of the lakes.

关键词： Algal community structure Biogeographic pattern Ecological networks Urban lakes Structural equation model

Lead‑Free Perovskite materials for Solar Cells

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2021年第4期13卷 110-145页

作者： Minghao Wang Wei Wang ben ma Wei Shen Lihui Liu Kun Cao Shufen Chen Wei Huang Key Laboratory for Organic Electronics and Information Displays&Jiangsu Key Laboratory for Biosensors Institute of Advanced Materials(IAM)Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)Nanjing University of Posts&Telecommunications(NUPT)9 Wenyuan RoadNanjing 210023People’s Republic of China Frontiers Science Center for Flexible Electronics Xi’an Institute of Flexible Electronics(IFE)and Xi’an Institute of Biomedical Materials&EngineeringNorthwestern Polytechnical University127 West Youyi RoadXi’an 710072People’s Republic of China

The toxicity issue of lead hinders large-scale commercial production and photovoltaic field application of lead halide *** novel non-or low-toxic perovskite materials have been explored for development of environmentally friendly lead-free perovskite solar cells(PSCs).This review studies the substitution of equivalent/heterovalent metals for Pb based on first-principles calculation,summarizes the theoretical basis of lead-free perovskites,and screens out some promising lead-free candidates with suitable bandgap,optical,and electrical ***,it reports notable achievements for the experimental studies of lead-free perovskites to date,including the crystal structure and material bandgap for all of lead-free materials and photovoltaic performance and stability for corresponding *** review finally discusses challenges facing the successful development and commercialization of lead-free PSCs and predicts the prospect of lead-free PSCs in the future.

关键词： Solar cells Perovskite Lead-free First-principles calculation Photovoltaic

Application of a Simple Semi-empirical Interatomic Potential Model to Phonon Density of States of Fe_(3)Al

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1999年第12期16卷 914-916页

作者： LIU Shao-jun CAI Jun DUAN Su-qing ma ben-kun Department of Physics Beijing Normal UniversityBeijing 100875 CCAST(World Laboratory) P.O.Box 8730Beijing 100080 Institute of Applied Physics and Computational mathematics Beijing 100080

We proposed a simple analytical interatomic potential model by extending the framework of embedded-atom model to include the non-central three-body potentials. This model can be easily applied to treat transition metals and their alloys based on the very recently developed lattice inversion method. We used the model to calculate the phonon density of states and entropy of Fe3AI, and the results were in agreement with the experimental data.

关键词： alloys entropy metals

Bronchogenic cysts with infection in the chest wall skin of a 64-yearold asymptomatic patient: A case report

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2022年第23期10卷 8392-8399页

作者： ben ma Kai-Wen Fu Xu-Dong Xie Yue Cheng Sheng-Qiang Wang Department of General Chongqing University Cancer HospitalChongqing 400030China

BACKGROUND Skin bronchogenic cysts are extremely rare congenital bronchocystic changes caused by the abnormal development of the trachea,bronchial trees or lung buds during the embryonic *** first case of skin bronchogenic cysts was reported in *** then,this disease has attracted increasing attention,but due to the low incidence,its pathogenesis is still not *** SUMmaRY Here,we report another case of skin bronchogenic cysts with infection in a 64-year-old female *** patient had no symptoms for more than 60 years until her chest wall was recently found to be swollen,and she felt pain and *** the same time,secretions were found on the surface of the *** Doppler ultrasound examination showed abnormal echoes in the soft tissue under the frontal chest wall,suggesting the presence of *** puncture resulted in about 2 mL of pus and showed the presence of more acute inflammatory *** final clinical diagnosis was skin cyst with infection,and surgery was carried *** pathological results obtained after surgery showed that the cystic wall was covered with column-like cilia epithelial cells,and the interstitial structure was partially inundated with inflammatory *** a variety of examinations and clinical diagnoses,we finally confirmed that the patient was suffering from bronchogenic *** This article not only describes the case of an elderly patient with rare skin bronchogenic cysts with infection but also provides a detailed and correct diagnosis and a successful treatment process,which is of great value for the diagnosis and treatment of the disease.

关键词： Bronchogenic cyst Chest wall infection Dermal cyst benign chest wall lesion Case report

Effect of the Vibrational Modes on the Ag-Cu Phase Diagram

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 Physics Letters 2000年第7期17卷 522-524页

作者： DUAN Su-Qing ZHAO Xian-Geng LIU Shao-Jun ma ben-Kun Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088 Department of Physics Beijing Normal UniversityBeijing 100875

We calculated the vibrational free energies of the selected ordered compounds in the Ag-Cu system by using two kinds of methods: (1) calculating the phonon dispersion and density of states and the consequently vibrational free energies by using the method of ab initio inverted interatomic potentials and dynamic matrix;(2) the vibrational free energies determined by a Debye-Griineisen approximation. The Ag-Cu phase diagram is calculated by the cluster variation method. The results show that the solubility at Ag-rich end of the calculated phase diagram considering vibrational modes by using the first method is in better agreement with the experimental.

关键词： method vibrational diagram