检索结果-南通市图书馆

Recess-free enhancement-mode AlGaN/GaN RF HEMTs on Si substrate

在线全文

学校读者我要写书评

暂无评论

Journal of Semiconductors 2024年第6期45卷 81-86页

作者： Tiantian Luan Sen Huang Guanjun Jing Jie Fan Haibo Yin Xinguo Gao Sheng Zhang Ke Wei Yankui Li Qimeng Jiang Xinhua Wang Bin Hou Ling Yang Xiaohua Ma Xinyu Liu high-Frequency high-voltage Device and Integrated Circuits R&D Center Institute of Microelectronics of Chinese Academy of SciencesBe i-jing 100029China School of integrated Circuits University of Chinese Academy of SciencesBeijing 100049China Faculty of integrated Circuits Xidian UniversityXi’an 710071China

Enhancement-mode(E-mode)GaN-on-Si radio-frequency(RF)high-electron-mobility transistors(HEMTs)were fabri-cated on an ultrathin-barrier(UTB)AlGaN(<6 nm)/GaN heterostructure featuring a naturally depleted 2-D electron g... 详细信息

Enhancement-mode(E-mode)GaN-on-Si radio-frequency(RF)high-electron-mobility transistors(HEMTs)were fabri-cated on an ultrathin-barrier(UTB)AlGaN(high threshold voltage(VTH)of+1.1 V with good uniformity.A maxi-mum current/power gain cut-off frequency(fT/fMAX)of 31.3/99.6 GHz with a power added efficiency(PAE)of 52.47%and an out-put power density(Pout)of 1.0 W/mm at 3.5 GHz were achieved on the fabricated E-mode HEMTs with 1-μm gate and Au-free ohmic contact.

关键词： AlGaN/GaN heterostructure ultrathin-barrier enhancement-mode radio-frequency power added efficiency silicon substrate

First-principles study of electronic and magnetic properties of Fe atoms on Cu_(2)N/Cu(100)

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第8期33卷 498-503页

作者：陈佳乐胡军 institute of high Pressure Physics School of Physical Science and TechnologyNingbo UniversityNingbo 315211China

First-principles calculations were conducted to investigate the structural,electronic,and magnetic properties of single Fe atoms and Fe dimers on Cu_(2)N/Cu(100).Upon adsorption of an Fe atom onto Cu_(2)N/Cu(100),robust Fe-N bonds form,resulting in the incorporation of both single Fe atoms and Fe dimers within the surface Cu_(2)N *** partial occupancy of Fe-3d orbitals lead to large spin moments on the Fe ***,both single Fe atoms and Fe dimers exhibit in-plane magnetic anisotropy,with the magnetic anisotropy energy(MAE)of an Fe dimer exceeding twice that of a single Fe *** magnetic anisotropy can be attributed to the predominant contribution of the component along the x direction of the spin-orbital coupling ***,the formation of Fe-Cu dimers may further boost the magnetic anisotropy,as the energy levels of the Fe-3d orbitals are remarkably influenced by the presence of Cu *** study manifests the significance of uncovering the origin of magnetic anisotropy in engineering the magnetic properties of magnetic nanostructures.

关键词： magnetic nanostructures magnetic anisotropy spin–orbital coupling ultrathin substrate

Study on surface discharge of nonlinear conductive epoxy resin/SrTiO3 composites in 80–300 K temperature zone

在线全文

学校读者我要写书评

暂无评论

high voltage 2024年第1期9卷 117-126页

作者： Yunqi Xing Bin Wang Mingyang Wang Jiakai Chi Peng Jia Rongjin Huang State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of TechnologyTianjinChina Key Laboratory of Electormagnetic Field and Electrical Apparatus Reliability of Hebei Province Hebei University of TechnologyTianjinChina Key Laboratory of Special Machine and high voltage Apparatus(Ministry of Education) Shenyang University of TechnologyShenyangChina State Grid Tianjin high voltage Company TianjinChina China Energy Engineering Group Tianjin Electric Power Design institute Co. Ltd.TianjinChina CAS Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryBeijingChina

Bisphenol F epoxy resin(EP)is often used in terminal current lead insulation of superconducting equipment because of its good insulation performance,high mechanical strength,good toughness at cryogenic temperatures,and resistance to cold shock and heat ***,due to the wide temperature range of 80–300 K and the strong electric field,the EP-N_(2)interface is prone to surface flashover,resulting in terminal insulation *** improve the reliability of the current lead insulation,non-linear conductive EP/strontium titanate(SrTiO_(3))composites were prepared by modification with nano *** changes of dielectric,surface discharge,flashover,and trap distribution characteristics of composite materials were studied,and the mechanism of SrTiO_(3)on the surface flashover of composite materials was *** results show that the conductivity of the composite increases with the rise of SrTiO_(3)filling content,and the amplitude of improvement is greater under the strong electric field,showing a more significant *** composite has a lower trap energy level and a greater number of shallow traps compared to pure EP,which accelerates surface charge detrapping and reduces charge accumulation,effectively enhancing the discharge and surface flashover voltage of the composite.

关键词： composites composite insulation

Detector performance of the Gamma-ray Transient Monitor onboard DRO-A satellite

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

Science China(Physics,Mechanics & Astronomy) 2024年第11期Mechanics & Astronomy) .卷 79-94页

作者： Pei-Yi Feng Zheng-Hua An Da-Li Zhang Chen-Wei Wang Chao Zheng Sheng Yang Shao-Lin Xiong Jia-Cong Liu Xin-Qiao Li Ke Gong Xiao-Jing Liu Min Gao Xiang-Yang Wen Ya-Qing Liu Xiao-Yun Zhao Fan Zhang Xi-Lei Sun Hong Lu Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences University of Chinese Academy of Sciences State Key Laboratory of Particle Detection and Electronics Institute of High Energy Physics Chinese Academy of Sciences

The Gamma-ray Transient Monitor(GTM) is an all-sky monitor onboard the Distant Retrograde Orbit-A(DRO-A) satellite with the scientific objective of detecting gamma-ray transients ranging from 20 ke V to 1 MeV. The GTM was equipped with five Gamma-ray Transient Probe(GTP) detector modules utilizing a NaI(Tl) scintillator coupled with a SiPM array. To reduce the SiPM noise, GTP uses a dedicated dual-channel coincident readout design. In this work, we first studied the impact of different coincidence times on the detection efficiency and ultimately selected a 0.5 μs time coincidence window for offline data processing. To test the performance of the GTPs and validate the Monte-Carlo-simulated energy response, we conducted comprehensive ground calibration tests using the Hard X-ray Calibration Facility(HXCF) and radioactive sources, including the energy response, detection efficiency, spatial response, bias-voltage response, and temperature dependence. We extensively present the ground calibration results and validate the design and mass model of the GTP detector, thus providing the foundation for in-flight observations and scientific data analysis.

关键词： NaI(Tl) detector energy response ground calibration gamma-ray detector DRO-A satellite

同方期刊数据库

Experimental and numerical investigation on alternatives to sandy gravel

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第1期31卷 130-141页

作者： V.Denefeld H.Aurich Fraunhofer institute for high-Speed Dynamics Ernst-Mach-Institut(EMI)Ernst-Zermelo-Str.479104FreiburgGermany Fraunhofer institute for high-Speed Dynamics Ernst-Mach-Institut(EMI)Am Christianswuhr 279400KandernGermany

The NATO agreement STANAG 4569 defines the protection levels for the occupants of logistic and light armored *** Allied Engineering Publication,AEP-55,Volume 2 document outlines the test conditions for underbelly improvised explosive device(IEDs),which must be buried in water-saturated sandy *** use of sandy gravel has some drawbacks,for instance reproducibility,time consumption,and *** paper focuses on the investigation of four alternatives to sandy gravel,which could produce similar specific and cumulative impulses:a concrete pot filled with water,a concrete pot filled with quartz sand,a steel pot without filling and a concrete pot filled with glass spheres(diameter 200μm—300μm)and different water *** impulses are measured with a ring technology developed at the Fraunhofer EMI.A numerical soil model based on the work of Marrs,2014 and Fi serov a,2006 and considering the soil moisture was used to simulate the experiments with glass spheres at different water contents,showing much better agreement with the experiments than the classical Laine&Sandvik model,even for high saturation *** results can be used to create new test conditions at original scale that are more cost-effective,more reproducible and simpler to manage in comparison to the current tests carried out with STANAG sandy gravel.

关键词： Improvised explosive device(IED) Specific impulse Momentum transfer Sandy gravel Glass spheres Numerical model Soil moisture

In-situ electrochemical study on the eff ects of Fe(Ⅲ)on kinetics of pyrite acidic pressure oxidation

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2024年第4期43卷 814-825页

作者： Yu Zhang Can Cui Sen Lin Heping Li Lian Yang Yadian Xie Hailiang Hu Lingyun Zhou Huanjiang Wang Chunyan Li School of Chemical Engineering Guizhou Minzu UniversityGuiyang 550025China Key Laboratory of high-Temperature and high-Pressure Study of the Earth’s Interior Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

Fe(Ⅲ)has been proved to be a more eff ective oxidant than dissolved oxygen at ambient temperature,however,the role of Fe(Ⅲ)in pyrite acidic pressure oxidation was rarely discussed so *** this paper,in-situ electrochemical investigation was performed using a flow-through autoclave system in acidic pressure oxidation *** results illustrated that increasing Fe(Ⅲ)concentrations led to raising in redox potential of the solution,and decreased passivation of pyrite caused by deposition of elemental *** of Fe(Ⅲ)at pyrite surface was a fast reaction with low activation energy,it was only slightly promoted by rising ***,the oxidation rate of pyrite at all investigated Fe(Ⅲ)concentrations increased obviously with rising temperatures,the anodic reaction was the rate-limiting step in the overall *** energy of pyrite oxidation decreased from 47.74 to 28.79 kJ/mol when Fe(Ⅲ)concentration was increased from 0.05 to 0.50 g/L,showing that the reaction kinetics were limited by the rate of electrochemical reaction at low Fe(Ⅲ)concentrations,while,it gradually turned to be diffusion control with increasing Fe(Ⅲ)concentrations.

关键词： Pyrite Pressure oxidation Fe(Ⅲ) In-situ electrochemistry Hydrothermal experiment

A Health State Prediction Model Based on Belief Rule Base and LSTM for Complex Systems

在线全文

学校读者我要写书评

暂无评论

Intelligent Automation & Soft Computing 2024年第1期39卷 73-91页

作者： Yu Zhao Zhijie Zhou Hongdong Fan Xiaoxia Han JieWang Manlin Chen high-Tech institute of Xi’an Xi’an710025China

In industrial production and engineering operations,the health state of complex systems is critical,and predicting it can ensure normal *** systems have many monitoring indicators,complex coupling structures,non-linear and time-varying characteristics,so it is a challenge to establish a reliable prediction *** belief rule base(BRB)can fuse observed data and expert knowledge to establish a nonlinear relationship between input and output and has well modeling *** each indicator of the complex system can reflect the health state to some extent,the BRB is built based on the causal relationship between system indicators and the health state to achieve the prediction.A health state prediction model based on BRB and long short term memory for complex systems is proposed in this ***,the LSTMis introduced to predict the trend of the indicators in the ***,the Density Peak Clustering(DPC)algorithmis used todetermine referential values of indicators for BRB,which effectively offset the lack of expert ***,the predicted values and expert knowledge are fused to construct BRB to predict the health state of the systems by ***,the effectiveness of the model is verified by a case study of a certain vehicle hydraulic pump.

关键词： Health state predicftion complex systems belief rule base expert knowledge LSTM density peak clustering

Robust multi-sensor image matching based on normalized self-similarity region descriptor

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 Aeronautics 2024年第1期37卷 271-286页

作者： Xuecong LIU Xichao TENG Jing LUO Zhang LI Qifeng YU Yijie BIAN College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China high-Tech institute Qingzhou 262500China

Multi-modal image matching is crucial in aerospace applications because it can fully exploit the complementary and valuable information contained in the amount and diversity of remote sensing ***,it remains a challenging task due to significant non-linear radiometric,geometric differences,and noise across different *** improve the performance of heterologous image matching,this paper proposes a normalized self-similarity region descriptor to extract consistent structural *** first construct the pointwise self-similarity region descriptor based on the Euclidean distance between adjacent image blocks to reflect the structural properties of multi-modal ***,a linear normalization approach is used to form Modality Independent Region Descriptor(MIRD),which can effectively distinguish structural features such as points,lines,corners,and flat between multi-modal *** further improve the matching accuracy,the included angle cosine similarity metric is adopted to exploit the directional vector information of multi-dimensional feature *** experimental results show that the proposed MIRD has better matching accuracy and robustness for various multi-modal image matching than the state-of-the-art *** can effectively extract consistent geometric structure features and suppress the influence of SAR speckle noise using non-local neighboring image blocks operation,effectively applied to various multi-modal image matching.

关键词： Remote sensing Multi-modal image matching Template matching Feature descriptor Similarity metric Synthetic Aperture Radar(SAR)

Analytical computation of magnetic field in coil-dominated superconducting quadrupole magnets based on racetrack coils

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第4期35卷 119-135页

作者： Chuang Shen Ying-Shun Zhu Fu-San Chen China Spallation Neutron Source Institute of High Energy PhysicsChinese Academy of Sciences1 Zhongziyuan RoadDongguan 523000China institute of high Energy Physics Chinese Academy of Sciences19B Yuquan RoadBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

currently,three types of superconducting quadrupole magnets are used in particle accelerators:cos 2θ,CCT,and ***,all three coil configurations have complex spatial geometries,which make magnet manufacturing and strain-sensitive superconductor applications *** with the three existing quadrupole coils,the racetrack quadrupole coil has a simple shape and manufacturing process,but there have been few theoretical *** this paper,the two-dimensional and three-dimensional analytical expressions for the magnetic field in coil-dominated racetrack superconducting quadrupole magnets are *** analytical expressions of the field harmonics and gradient are fully resolved and depend only on the geometric parameters of the coil and current ***,a genetic algorithm is applied to obtain a solution for the coil geometry parameters with field harmonics on the order of 10^(-4).Finally,considering the practical engineering needs of the accelerator interaction region,electromagnetic design examples of racetrack quadrupole magnets with high gradients,large apertures,and small apertures are described,and the application prospects of racetrack quadrupole coils are analyzed.

关键词： Superconducting quadrupole magnet Racetrack coil Multipole field Genetic algorithm Magnetic design