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CO oxidation under lean and stoichiometric conditions over ceriazirconia with very low metal contents(Cu,Co,Ag and Pt)

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Journal of Rare Earths 2024年第9期42卷 1669-1681,I0002页

作者： J.C.Martínez-Munuera M.P.Yeste A.García-García MCMA group Department of Inorganic Chemistry and Institute of MaterialsUniversity of AlicanteCarretera de San Vicente del Raspeig s/n03690San Vicente del RaspeigAlicanteSpain Solid Chemistry and Catalysis group Department of Materials ScienceMetallurgic Engineering and Inorganic ChemistryInstitute of Electronic Microscopy and Materials ResearchUniversity of CádizAp.40E-11510Puerto RealCádizSpain

In this work,several ceria-zirconia based catalysts with very lo w(and equimolar) metal contents were prepared,characterised and tested for the CO oxidatio n reaction(under lean and stoichiometric conditions),trying to emulate those conditions found in a diesel oxidation catalyst(DOC) system from a diesel engine and those encountered under gasoline exhaust(λ=1).The metals chosen are Cu,Co,Ag and Pt(as a reliable benchmark).The results reveal enormous differences among reducibility and catalytic activity despite quite similar structural and textural properties of the catalysts,showing differences among dispersion(Ag-catalyst seems to present a low level of dispersion).This catalyst seems to be characterised,as well,by a strong electronic interaction between Ce and Ag centres which is suggested to yield an improved reducibility under H_(2)-TPR ***,the order in catalytic activity(Cu>Ag>Co≈Pt>>support) seems not to follow the order found in reducibility and the Cu-catalyst seems to be the most active independently on the reaction conditions,yielding nearly overlapped CO oxidation catalytic *** restingly,a stro ng correlation between the catalytic activity under the two conditions tested and the OSC values of the Ce_(0.8)Zr_(0.2)O_(2)-supported metal catalysts is ***,OSC parameter measured at 150℃ can be used as a relevant descriptor to evaluate the CO oxidation activity at low and medium conversions for the investigated catalysts,much better than the H_(2)-TPR measurements.

关键词： CO oxidation Low metal content Ceria-zirconia Copper species OSC parameter Rare earths

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Effect of neodymium doping on structure,magnetic properties and microwave absorption performance of SrMnO_(3)

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Journal of Rare Earths 2024年第2期42卷 354-363,I0005页

作者： Jixiang Yue Lichun Cheng Jilei Xiong Qingrong Yao Man Wang Yucheng Chen Qianxin Long Xiaojian Guo School of materials Science and Engineering Guilin University of Electronic TechnologyGuilin541004China Guangxi Key Laboratoryof Information materials Guilin University of electronic Technology Guilin541004China Anhui Jihua New materials Co. Ltd.Anqing246300China

A simple composite Sr_(1-x)Nd_(x)MnO_(3)(x=0,0.05,0.1,0.15,0.2) nano powders were successfully prepared by the sol-gel method as a light-weight broadband electromagnetic wave *** effect of Nd^(3+)doping on the structure,microstructure and properties of SrMnO_(3) was *** is found that with the doping of Nd^(3+),the space group of the SrMnO_(3) changes from p63/mmc to pm3m,and the crystalline shape starts to change from hexagonal to cubic *** electron microscopy(SEM) and Brunauer-Emmett-Teller(BET) tests confirm that the particle sizes of the sample decrease and the specific surface area increases,which are attributed to the inhibition of grain growth after Nd^(3+)is doped.X-ray photoelectron spectroscopy(XPS) shows that after Nd^(3+)doping,the content of oxygen vacancy increases,and Mn^(4+) converts to Mn^(3+).Due to the defects of the materials,the polarization effect is enhanced,thus,the dielectric and magnetic properties of the doped samples are *** maximum reflection loss of the Sr_(0.85)Nd_(0.15)MnO_(3) is-33.41 dB at 7.84 GHz for a thickness of 2.4 mm,while Sr_(0.9)Nd_(0.1)MnO_(3) has the best bandwidth performance at 2.32 GHz with a reflection loss below-10dB.

关键词： Sr_(1-x)Mn_xO_(3) Crystal structure Microwave absorption Magnetic properties Nano powder Rare earths

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A high aspect ratio surface micromachined accelerometer based on a SiC-CNT composite material

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microsystems & Nanoengineering 2024年第2期10卷 219-230页

作者： Jiarui Mo Shreyas Shankar Roberto Pezone Guoqi Zhang Sten Vollebregt Laboratory of electronic Components Technology and Materials(ECTM)Department of MicroelectronicsDelft University of TechnologyDelftThe Netherlands

Silicon carbide(SiC)is recognized as an excellent material for microelectromechanical systems(MEMS),especially those operating in challenging environments,such as high temperature,high radiation,and corrosive ***,SiC bulk micromachining is still a challenge,which hinders the development of complex SiC *** address this problem,we present the use of a carbon nanotube(CNT)array coated with amorphous SiC(a-SiC)as an alternative composite material to enable high aspect ratio(HAR)surface *** using a prepatterned catalyst layer,a HAR CNT array can be grown as a structural template and then densified by uniformly filling the CNT bundle with LPCVD *** electrical properties of the resulting SiC-CNT composite were characterized,and the results indicated that the electrical resistivity was dominated by the *** demonstrate the use of this composite in MEMS applications,a capacitive accelerometer was designed,fabricated,and *** fabrication results showed that the composite is fully compatible with the manufacturing of surface micromachining *** Young’s modulus of the composite was extracted from the measured spring constant,and the results show a great improvement in the mechanical properties of the CNTs after coating with *** accelerometer was electrically characterized,and its functionality was confirmed using a mechanical shaker.

关键词： composite surface electrical

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A High-Linear Radio Frequency Quadrature Modulator with Improved Sideband Suppression and Carrier Leakage Performance

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Tsinghua Science and Technology 2024年第3期29卷 635-643页

作者： Yingdan Jiang Zongguang Yu Shutong Wu Li Li Xuelian Liu School of electronic Science and Engineering Nanjing UniversityNanjing 210093China The 58th Research Institute of China electronic Technology group Corporation Wuxi 214072China

The quadrature modulator is a crucial block in transmitters that upconverts baseband signals to theRadio Frequency(RF)band of interest using local oscillator *** this paper,non-ideal factors thatinfluence the performance of the quadrature modulator are considered,and solutions are accordingly taken inthe quadrature modulator design.A high-linear RF quadrature modulator with improved sideband suppressionand carrier leakage performance is presented in this *** quadrature modulator implemented in the0.18-μm SiGe process uses the current bleeding technique to improve the general performance of the doublebalanced active Gilbert *** on-chip prescaler followed by two cascaded limiting amplifiers is designed toprovide accurate quadrature local oscillator *** at quadrature baseband signal input ports areproposed to eliminate DC *** measured sideband suppression achieves a performance of better than−43 dBc and carrier leakage is less than−38 dBm over the output RF frequency range of 30 MHz to 2.15 *** output 1 dB compression point equals 11.4 dBm at 800 MHz.

关键词： Radio Frequency(RF) quadrature modulator sideband suppression carrier leakage linearity

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Highly-sensitive wafer-scale transfer-free graphene MEMS condenser microphones

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microsystems & Nanoengineering 2024年第1期10卷 267-275页

作者： Roberto Pezone Sebastian Anzinger Gabriele Baglioni Hutomo Suryo Wasisto Pasqualina M.Sarro Peter G.Steeneken Sten Vollebregt Laboratory of electronic Components Technology and Materials(ECTM)Department of MicroelectronicsDelft University of TechnologyDelftThe Netherlands Infineon Technologies AG Am Campeon 1-15Neubiberg 85579Germany Kavli Institue of Nanoscience Department of Quantum NanoscienceDelft University of TechnologyDelftthe Netherlands Department of Precision and microsystems Engineering(PME) Delft University of TechnologyDelftThe Netherlands

Since the performance of micro-electro-mechanical system(MEMS)-based microphones is approaching fundamental physical,design,and material limits,it has become challenging to improve *** works have demonstrated graphene’s suitability as a microphone *** potential for achieving smaller,more sensitive,and scalable onchip MEMS microphones is yet to be *** address large graphene sizes,graphene-polymer heterostructures have been proposed,but they compromise performance due to added polymer mass and *** work demonstrates the first wafer-scale integrated MEMS condenser microphones with diameters of 2R=220-320μm,thickness of 7 nm multi-layer graphene,that is suspended over a back-plate with a residual gap of 5μ*** microphones are manufactured with MEMS compatible wafer-scale technologies without any transfer steps or polymer layers that are more prone to contaminate and wrinkle the *** designs,all electrically integrated are fabricated and characterized allowing us to study the effects of the introduction of a back-plate for capacitive *** devices show high mechanical compliances C_(m)=0.081-1.07μmPa^(−1)(10-100×higher than the silicon reported in the state-of-the-art diaphragms)and pull-in voltages in the range of 2-9.5 *** addition,to validate the proof of concept,we have electrically characterized the graphene microphone when subjected to sound *** estimated sensitivity of S_(1kHz)=24.3-321 mV Pa^(−1)for a V_(bias)=1.5 V was determined,which is 1.9-25.5×higher than of state-of-the-art microphone devices while having a~9×smaller area.

关键词： transfer plate approaching

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Effect of Co on Solidification Characteristics and Microstructural Transformation of Non-equilibrium Solidified Cu-Ni Alloys

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Journal of Wuhan University of Technology(materials Science) 2024年第2期39卷 444-453页

作者：安红恩 Bih-Lii Chua Ismail Saad Willey Yun Hsien Liew materials Engineering Research group Faculty of EngineeringUniversity Malaysia Sabah88400 Kota KinabaluSabahMalaysia College of Mechanical and electronic Engineering Huanghe Jiaotong UniversityJiaozuo 454950China Henan Engineering Technology Research Center on Intelligent Manufacturing Technology and Equipment Jiaozuo 454950China Centre of Research in Energy and Advanced materials Faculty of EngineeringUniversiti Malaysia SabahJalan UMS88400 Kota KinabaluSabahMalaysia Nano Engineering and materials Research group Faculty of EngineeringUniversity Malaysia Sabah88400 Kota KinabaluSabahMalaysia

Non-equilibrium solidification structures of Cu55Ni45 and Cu55Ni43Co2 alloys were prepared by the molten glass purification cycle superheating *** variation of the recalescence phenomenon with the degree of undercooling in the rapid solidification process was investigated using an infrared *** addition of the Co element affected the evolution of the recalescence phenomenon in Cu-Ni *** images of the solid-liquid interface migration during the rapid solidification of supercooled melts were captured by using a high-speed *** solidification rate of Cu-Ni alloys,with the addition of Co elements,was ***,the grain refinement structure with low supercooling was characterised using electron backscatter diffraction(EBSD).The effect of Co on the microstructural evolution during nonequilibrium solidification of Cu-Ni alloys under conditions of small supercooling is investigated by comparing the microstructures of Cu55Ni45 and Cu55Ni43Co2 *** experimental results show that the addition of a small amount of Co weakens the recalescence behaviour of the Cu55Ni45 alloy and significantly reduces the thermal strain in the rapid solidification *** the rapid solidification phase,the thermal strain is greatly reduced,and there is a significant increase in the characteristic undercooling ***,the addition of Co and the reduction of Cu not only result in a lower solidification rate of the alloy,but also contribute to the homogenisation of the grain size.

关键词： non-equilibrium solidification recalescence effect solidification character microstructure

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Large-scale distributed diffractive-interference hybrid photonic chiplets

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Advanced Photonics 2024年第4期6卷 7-8页

作者： Hang Chen Yichen Shen Tsinghua University Department of Electronic EngineeringBeijingChina Lightelligence group HangzhouChina

The rapid development of artificial general intelligence(AGI)introduces significant performance challenges for next-generation *** devices such as graphics processing units(GPUs)are constrained by computational and en... 详细信息

关键词： graphics hinder limitations

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Nitrogen-Doped Amorphous Carbon Homojunction from Palmyra Sugar as a Renewable Solar Cell

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Journal of Renewable materials 2024年第1期12卷 57-69页

作者： Budhi Priyanto Imam Khambali Irma Septi Ardiani Khoirotun Nadhiyah Anna Zakiyatul Laila M.Chasrun Hasani Bima Romadhon Retno Asih Yoyok Cahyono Triwikantoro Darminto Department of electronic Engineering Faculty of EngineeringUniversitas Muhammadiyah MalangKota MalangIndonesia Advanced materials Research group Department of PhysicsFaculty of Science and Data AnalyticsInstitut Teknologi Sepuluh NopemberSurabayaIndonesia Department of electronic Engineering Faculty of Industrials EngineeringInstitut Teknologi National MalangKota MalangIndonesia

An a-C/a-C:N junction,which used palmyra sugar as the carbon source and ammonium hydroxide(NH4OH)as the dopant source,was successfully deposited on the ITO glass substrate using the nano-spraying *** current-voltage relationship of the junction was found to be a Schottky-like contact,and therefore the junction shows the characteristic *** means the a-C and a-C:N are semiconductors with different types of ***,the samples showed an increase in current and voltage value when exposed to visible light(bright state)compared to the dark condition,thereby,indicating the creation of electron-hole pairs during the *** was also discovered that the relationship between current and voltage for the a-C/a-C:N junction sample formed a curve that satisfies the rule of the photovoltaic effect when exposed to visible light from a light *** exposure of this sample to direct sunlight at AM 1.5 conditions produced a curve that meets the rules for the emergence of the photovoltaic effect with higher characteristics for the current-voltage ***,the a-C/a-C:N junction sample is a solar cell successfully fabricated using a sample method and has a maximum efficiency of 0.0013%.

关键词： Solar cell amorphous carbon palmyra sugar

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Impact of device resistances in the performance of graphene‑based terahertz photodetectors

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Frontiers of Optoelectronics 2024年第2期17卷 87-97页

作者： O.Castelló Sofía M.López Baptista K.Watanabe T.Taniguchi E.Diez J.E.Velázquez-Pérez Y.M.Meziani J.M.Caridad J.A.Delgado-Notario Department of Applied Physics University of Salamanca37008 SalamancaSpain Unidad de Excelencia en Luz y Materia Estructurada(LUMES) University of Salamanca37008 SalamancaSpain Research Center for electronic and Optical materials National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Research Center for materials Nanoarchitectonics National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Nanotechnology group USAL-NanolabUniversity of Salamanca37008 SalamancaSpain

In recent years,graphene field-effect-transistors(GFETs)have demonstrated an outstanding potential for terahertz(THz)photodetection due to their fast response and *** features are essential to enable emerging THz applications,including 6G wireless communications,quantum information,bioimaging and ***,the overall performance of these photodetectors may be utterly compromised by the impact of internal resistances presented in the device,so-called access or parasitic *** this work,we provide a detailed study of the influence of internal device resistances in the photoresponse of high-mobility dual-gate GFET *** dual-gate architectures allow us to fine tune(decrease)the internal resistance of the device by an order of magnitude and consequently demonstrate an improved responsivity and noise-equivalent-power values of the photodetector,*** results can be well understood by a series resistance model,as shown by the excellent agreement found between the experimental data and theoretical *** findings are therefore relevant to understand and improve the overall performance of existing high-mobility graphene photodetectors.

关键词： Graphene THz Photodetector Field-effect transistor Plasmonic

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Multi-scale cross-domain alignment for person image generation

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CAAI Transactions on Intelligence Technology 2024年第2期9卷 374-387页

作者： Liyuan Ma Tingwei Gao Haibin Shen Kejie Huang Department of Information Science&electronic Engineering Zhejiang UniversityHangzhouZhejiangChina Alibaba group HangzhouChina

Person image generation aims to generate images that maintain the original human appearance in different target *** works have revealed that the critical element in achieving this task is the alignment of appearance domain and pose *** alignment methods,such as appearance flow warping,correspondence learning and cross attention,often encounter challenges when it comes to producing fine texture *** approaches suffer from limitations in accurately estimating appearance flows due to the lack of global receptive ***,they can only perform cross-domain alignment on high-level feature maps with small spatial dimensions since the computational complexity increases quadratically with larger feature *** this article,the significance of multi-scale alignment,in both low-level and high-level domains,for ensuring reliable cross-domain alignment of appearance and pose is *** this end,a novel and effective method,named Multi-scale Crossdomain Alignment(MCA)is ***,MCA adopts global context aggregation transformer to model multi-scale interaction between pose and appearance inputs,which employs pair-wise window-based cross ***,leveraging the integrated global source information for each target position,MCA applies flexible flow prediction head and point correlation to effectively conduct warping and fusing for final transformed person image *** proposed MCA achieves superior performance on two popular datasets than other methods,which verifies the effectiveness of our approach.

关键词： artificial intelligence image processing image reconstruction

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