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Surface reconstruction,modification and functionalization of natural diatomites for miniaturization of shaped heterogeneous catalysts

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纳米材料科学:英文版 2023年第3期5卷 293-311页

作者： Bowen Li Tian Wang Qiujian Le Runze Qin Yuxin Zhang Hua Chun Zeng Department of Chemical and Biomolecular Engineering Faculty of EngineeringNational University of Singapore10 Kent Ridge Crescent119260Singapore State Key Laboratory of Mechanical Transmissions College of Materials Science and EngineeringChongqing UniversityChongqing400044PR China

Since the discovery of mesoporous silica in 1990s,there have been numerous mesoporous silica-based nanomaterials developed for catalytic applications,aiming at enhanced catalytic activity and ***,there have also been considerable interests in endowing them with hierarchical porosities to overcome the diffusional limitation for those with long unimodal *** processes of making mesoporous silica largely rely on chemical sources which are relatively expensive and impose environmental concerns on their *** this regard,it is desirable to develop hierarchical silica supports from natural ***,we present a series of work on surface reconstruction,modification,and functionalization to produce diatomite-based catalysts with original morphology and macro-meso-micro porosities and to test their suitability as catalyst supports for both liquid-and gas-phase *** wet-chemical routes were developed to introduce mesoporosity to both amorphous and crystalline ***,we have used computational modeling to affirm that the diatomite morphology can improve catalytic performance based on fluid dynamics ***,one could obtain this type of catalysts from numerous natural diatoms that have inherently intricate morphologies and shapes in micrometer *** principle,such catalytic nanocomposites acting as miniaturized industrial catalysts could be employed in microfluidic reactors for process intensification.

关键词： Heterogeneous catalysis Diatomites Silica Catalytic materials miniaturization Sustainable chemistry

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Monolithic macroporous catalysts—a new route for miniaturization of water-gas shift reactor

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Journal of Natural Gas Chemistry 2009年第4期18卷 436-440页

作者： Hao Liang Yuan Zhang Yuan Liu Department of Catalysis Science and Technology School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

Monolithic macroporous Pt/CeO2/Al2O3 catalysts were prepared using concentrated emulsions synthesis route, and the obtained samples were characterized with SEM, TG, TEM, XRD and TPR techniques. These monolithic catalysts were applied to water gas shift （WGS） reaction in reformed gases. The SEM and TEM results indicated that the monoliths possessed macroporosity, and that the platinum particles homogeneously dispersed on the supports with the particle size in the range of 1-2 nm. The reducibility of the catalysts was characterized by TPR method, and it was shown that the monolithic PtOx/CeO2/Al2O3 exhibited the similar reducibility property to that of the particle PtOx/CeO2 reported in literatures. The CO conversion over the monolithic catalysts is higher than that over micro-reactor catalysts for WGS reaction in the reformed gases conditions, indicating that the monolithic macroporous catalysts is a potential new route for miniaturization of WGS reactor.

关键词： macroporous monolith miniaturization water gas shift platinum

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A Novel Frequency Selective Surface with Improved miniaturization Performance

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Journal of Electromagnetic Analysis and Applications 2012年第3期4卷 108-111页

作者： Wanlu Li Tong Zhang Guohui Yang Qun Wu Department of Electrical Engineering The Fu Foundation School of Engineering and Applied Science Columbia University New York USA. Department of Microwave Engineering Harbin Institute of Technology Harbin China

Based on previous work, a novel Frequency Selective Surface (FSS) consisting of two metallic layers is proposed. The first layer is inductive-designed to generate the band-pass performance, while the second layer is capacitive-designed so that the miniaturization characteristic can be further improved. As a result, compared with the traditional single-layer structure, the profile of the FSS proposed is relatively small with the cell’s dimension only 0.0814λ × 0.0814λ. Moreover, the structure’s stability corresponding to waves of different polarizations and incident angles are also testified, which ensures the practicability of the proposed structure.

关键词： requency Selective Surface (FSS) miniaturization Stability

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Miniaturized power detection module operating in millimeter wave band

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Journal of Electronic Science and Technology 2024年第2期22卷 69-76页

作者： Xiang Zhou Zhi-Yong Zhong School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China

The miniaturized broadband detection module can be embedded into the microwave application system such as the front end of the transmitter to detect the power or other parameters in real *** is highly prospective in military and scientific *** this paper,a broadband power detection module operating at 26.5 GHz-40.0 GHz is designed by using low-barrier Schottky diode as the detector and a comparator for threshold *** module can dynamically detect the power range between-10 dBm and 10 dBm with the detection accuracy of 0.1 ***,the temperature compensation circuit is also applied to improve the measurement *** a result,the resulted error low to±1 dB in the temperature range of -55℃ to +85℃ is *** designed module is encapsulated by a Kovar alloy with a small volume of 9 mm×6 mm×3 *** endows the designed module the advantages of small size,easy integration,and low cost,and even it is applicable to high-reliability environments such as satellites.

关键词： Diode miniaturization Power detection Temperature compensation

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Compact multilayer liquid crystal polymer lowpass filter with 8-shaped inductor

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The Journal of China Universities of Posts and Telecommunications 2024年第3期31卷 80-86页

作者： Liu Weihong Wang Guoxiu Liu Qingran School of Electronic Engineering Xi'an University of Posts and TelecommunicationsXi'an 710121China

Lumped element lowpass filter(LPF)for ultra-high frequency(UHF)radio frequency(RF)front-end system is presented based on multilayer liquid crystal polymer(LCP).The lumped element LPF can achieve miniaturization and one transmission zero on the stopband by the 8-shaped *** lumped element LPF is fabricated on a 4-layer LCP substrate with a compact size of 9 mm×14 mm×0.193 *** measured cut off frequency of the lumped element LPF is 0.5 GHz with insertion loss(IL)less than 0.37 *** measured and simulated results suggest that it is a possible candidate for the application of UHF RF front-end system.

关键词： lowpass filter(LPF) multilayer liquid crystal polymer(LCP) miniaturization 8-shaped inductor

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Cell architecture designs towards high-energy-density microscale energy storage devices

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Nano Research Energy 2024年第2期3卷 69-82页

作者： Kwon-Hyung Lee Sang-Young Lee Ulsan Advanced Energy Technology R&D Center Korea Institute of Energy Research(KIER)Ulsan44776Republic of Korea Department of Chemical and Biomolecular Engineering Yonsei UniversitySeoul03722Republic of Korea

The rapid growth of miniaturized electronics has led to an urgent demand for microscale energy storage devices(MESDs)to sustainably power the micro electronic ***,most MESDs reported to date have suffered from the limited energy densities and shape versatility compared to conventional large-scale counterparts because of the architectural constraints inherent in microfabrication-based cell manufacturing and cell dimension/*** review addresses the cell architecture design for MESDs that can achieve both miniaturization and high energy *** provide a comprehensive overview of five types of cell architectures of MESDs and their fabrication *** addition,to enable practical applications of MESDs,several cell design approaches are presented with the aim of minimizing the inactive parts of the cell and maximizing the performance metrics of ***,we discuss development direction and outlook of MESDs with a focus on materials chemistry,energy-dense electrochemical systems,and cell performance normalization,which will help to expand their applications and manufacturing scalability.

关键词： microscale energy storage device cell architecture microfabrication miniaturization high-energy-density

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220 GHz Multi Circuit Integrated Front End Based on Solid-State Circuits for High Speed Communication System

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Chinese Journal of Electronics 2022年第3期31卷 569-580页

作者： NIU Zhongqian ZHANG Bo DAI Bingli ZHANG Jicong SHEN Fang HU Yi FAN Yong ZHANG Yihan School of Electronic Science and Engineering University of Electronic Science and Technology of China Chongqing Institute of Microelectronics Industry Technology University of Electronic Science and Technology of China

This paper presents the research on a 220 GHz multi circuit inte-grated front end based on solidstate circuits. This integrated front end integrates a 220 GHz subharmonic mixer, a 110 GHz tripler, a 110 GHz 8 d B hybrid coupler and a 220 GHz waveguide bandpass filter(BPF) in one single block. Compared to the traditional transceivers which usually use cascade connection of the independent mixers and multipliers, the size of the proposed multi circuit integrated front-end block is 25 mm × 20 mm × 20 mm, ten times smaller than the cascading transceiver. In order to check the tripler’s output power, a modified compact 110 GHz 8 d B hybrid coupler is set between mixer and tripler. Due to the characteristics of the hybrid coupler, the deterioration of cascading transceiver’s performance caused by mismatch has also been improved. In addition, to achieve single sideband(SSB) communication, a 220 GHz BPF with high selectivity is integrated in the circuit. The measured conversion loss of the fabricated multi circuit integrated front end is less than 11 d B, where the LO and RF frequency are 37 and 210-220 GHz. Based on this front-end, a 220 GHz high speed communication system has been setup and it can achieve 10 Gbps data transmission using 16 QAM modulation.

关键词： THz solid state circuits Low connection loss Multi circuit integrated front end miniaturization Single sideband communication

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Design of Wireless Power Transfer with High Efficiency for Biomedical Implants

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Journal of Beijing Institute of Technology 2022年第1期31卷 53-60页

作者： Qingya Li Zhiwei Zhang Jingna Mao Institute of Automation Chinese Academy of SciencesBeijing 100190China

Wireless power transfer(WPT)technology is a popular choice for biomedical implant *** demands of higher efficiency and smaller implantation size are hard to compromise in previous *** the present work,an implantable magnetic coupling resonant WPT system in-tegrated with a metasurface element working at 430 MHz is *** planar copper coil components for the transmitting and receiving structures are used to construct the primary system,and then the metasurface element is integrated to constitute the whole WPT *** effects of the distances between the transmitting coil and skin surface,between the skin surface,and receiv-ing coil are *** results show that the efficiency will be enhanced by 38-50 dB integrat-ing with the metasurface.

关键词： wireless power transfer(WPT) miniaturization metasurface

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A compact and closed-loop spin-exchange relaxation-free atomic magnetometer for wearable magnetoencephalography

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Chinese Physics B 2023年第4期32卷 277-282页

作者：郭清乾胡涛冯晓宇张明康陈春巧张欣姚泽坤徐佳玉王青付方跃张寅常严杨晓冬 Suzhou Institute of Biomedical Engineering and Technology Chinese Academy of SciencesSuzhou 215163China School of Biomedical Engineering(Suzhou) Division of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefei 230026China Jihua Laboratory Foshan 528000China School of Electronic and Information Engineering Changchun University of Science and TechnologyChangchun 130022China

Atomic magnetometers operated in the spin-exchange relaxation-free(SERF)regime are the promising sensor to replace superconducting quantum interference devices(SQUIDs)in the biomagnetism *** SERF magnetometer with compact size and good performance is crucial to the new generation of wearable magnetoencephalography(MEG)*** this paper,we developed a compact and closed-loop SERF magnetometer with the dimensions of 15.0×22.0×30.0 mm^(3)based on a single-beam *** bandwidth of the magnetometer was extended to 675 Hz while the sensitivity was maintained at 22 f T/Hz^(1/2).A nearly 3-fold enhancement of the bandwidth was obtained in comparison with the open-loop *** implementation of the closed-loop control also greatly improved the dynamic range,enabling the magnetometer to be robust against the disturbance of the ambient ***,the magnetometer was successfully applied for the detection of humanα-rhythm and auditory evoked fields(AEFs),which demonstrated the potential to be extended to multi-channel MEG measurements for future neuroscience studies.

关键词： atomic magnetometer miniaturization closed-loop magnetoencephalography(MEG)

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State of the Art on Micromilling of Materials,a Review

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Journal of Materials Science & Technology 2012年第8期28卷 673-685页

作者： M.A.Cmara J.C. Campos Rubio A.M. Abro J.P. Davim Department of Mechanical Engineering Universidade Federal de Minas GeraisAv.Ant onio Carlos6627-Pampulha Belo Horizonte MGCEP:31.270-901Brazil Department of Mechanical Engineering University of AveiroCampus Universitrio de Santiago3810-193AveiroPortugal

The trend towards miniaturization has increased dramatically over the last decade, especially within the fields concerned with bioengineering, microelectronics, and aerospace. Micromillin8 is among the principal manu- facturing processes which have allowed the development of components possessing micrometric dimensions, being used to the manufacture of both forming tools and the final product. The aim of this work is to present the principal aspects related to this technology, with emphasis on the work material requirements, tool ma- terials and geometry, cutting forces and temperature, quality of the finished product, process modelling and monitoring and machine tool requirements. It can be noticed that size effect possesses a relevant role with regard to the selection of both work material （grain size） and tooling （edge radius）. Low forces and temper- ature are recorded during micromillin8, however, the specific cutting force may reach high values because of the ploughing effect observed as the uncut chip thickness is reduced. Finally, burr formation is the principal concern with regard to the quality of the finished part.

关键词： Micro-milling Micromachining Size effect miniaturization

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