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Transactions of Nonferrous Metals Society of China 2020年第11期30卷 3067-3077页

作者： Shi-geng LI ru-tie liu Xiang XIONG State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Department of Materials and Chemistry Engineering Pingxiang UniversityPingxiang 337000China

Spherical carbonyl iron(Fe)powders were coated with magnesioferrite(MgFe2O4)insulating coating layer and then mixed with epoxy-modified silicone resin(ESR).Soft magnetic composites(SMCs)were fabricated by compaction of the coated powders and annealing *** electron microscopy(TEM),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),X-ray diffractometry(XRD)and X-ray photoelectron spectroscopy(XPS)revealed that the MgFe2O4 layer was coated on the surface of the iron *** magnetic properties of SMCs were determined using a vibrating sample magnetometer and an auto testing system for magnetic *** results showed that the SMCs prepared at 800 MPa and 550℃ exhibited a significant core loss of 167.5 W/kg at 100 kHz and 50 mT.

关键词： soft magnetic composites in-situ oxidation preparation magnesioferrite insulating coating layer annealing treatment magnetic properties

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含硫高速钢的高温摩擦性能(英文)

中国有色金属学会会刊：英文版 2013年第6期23卷 1674-1680页

作者：刘如铁熊翔中南大学粉末冶金国家重点实验室长沙410083

引入适量的硫可以明显改善铁基材料的摩擦学性能。采用粉末冶金技术制备了含硫高速钢样品材料,采用销盘高温摩擦试验机研究了该样品材料与不同配副(自对偶和GT35钢结硬质合金)摩擦时的高温摩擦性能,通过SEM、EDS和XPS检测了摩擦面,并分... 详细信息

引入适量的硫可以明显改善铁基材料的摩擦学性能。采用粉末冶金技术制备了含硫高速钢样品材料,采用销盘高温摩擦试验机研究了该样品材料与不同配副(自对偶和GT35钢结硬质合金)摩擦时的高温摩擦性能,通过SEM、EDS和XPS检测了摩擦面,并分析了其摩擦机理。结果表明:与自对偶盘和GT35盘这2种对偶材料摩擦时,摩擦因数的变化趋势是随着温度的升高而逐渐降低的,磨损率则是随着温度的升高而逐渐变大的;在400℃和700℃时的摩擦因数曲线比室温时更加平稳,与GT35摩擦时样品材料的综合高温摩擦性能最佳;在400℃以下时,由于样品材料中硫化物的软化会使得材料的摩擦因数随着温度的升高而降低,在400℃以上时样品材料摩擦因数的降低主要是由于摩擦面的氧化物作用而引起的。

关键词：高速钢硫钢结硬质合金高温滑动摩擦磨损

A Study of Electromyogram Based on Human-Computer Interface

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Journal of Electronic Science and Technology of China 2009年第1期7卷 69-73页

作者： Jun-ru Ren tie-Jun liu Yu Huang De-Zhong Yao Key Laboratory for NeuroInformation of Ministry of Education School of Life University of Electronic Science and Technology of China Chengdu 610054 China

In this paper, a new control system based on forearm electromyogram （EMG） is proposed for computer peripheral control and artificial prosthesis control. This control system intends to realize the commands of six pre-defined hand poses： up, down, left, right, yes, and no. In order to research the possibility of using a unified amplifier for both electroencephalogram （EEG） and EMG, the surface forearm EMG data is acquired by a 4-channel EEG measurement system. The Bayesian classifier is used to classify the power spectral density （PSD） of the signal. The experiment result verifies that this control system can supply a high command recognition rate （average 48%） even the EMG data is collected with an EEG system just with single electrode measurement.

关键词： Bayesian classifier forearm electro-myogram hand pose human-computer interface.

Research progress and prospect of low-carbon biological technology for nitrate removal in wastewater treatment

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Frontiers of Environmental Science & Engineering 2024年第7期18卷 1-21页

作者： ru Zheng Kuo Zhang Lingrui Kong Sitong liu College of Environmental Sciences and Engineering Peking UniversityBeijing 100871China Key Laboratory of Water and Sediment Sciences Ministry of Education of ChinaBeijing 100871China Eco-Environment and Resource Efficiency Research Laboratory School of Environment and EnergyPeking University Shenzhen Graduate SchoolShenzhen 518055China

Wastewater treatment plants are the major energy consumers and significant sources of greenhouse gas emissions,among which biological nitrogen removal of wastewater is an important contributor to carbon ***,traditional heterotrophic denitrification still has the problems of excessive residual sludge and the requirement of external carbon ***,the development of innovative low-carbon nitrate removal technologies is *** review outlines the key roles of sulfur autotrophic denitrification and hydrogen autotrophic denitrification in low-carbon wastewater *** discovered nitrate/nitrite dependent anaerobic methane oxidation enables sustainable methane emission reduction and nitrogen removal by utilizing available methane in *** microorganisms exhibited a promising potential to achieve carbon-negative nitrate ***,the algal-bacterial symbiosis system and photogranules offer effective and prospective low-carbon options for nitrogen ***,the emerging nitrate removal technology of photoelectrotrophic denitrification and the underlying,photoelectron transfer mechanisms are ***,we summarize and prospect these technologies,highlighting that solar-driven biological nitrogen removal technology is a promising area for future sustainable wastewater *** review has important guiding significance for the design of low-carbon wastewater treatment systems.

关键词： Carbon emissions Low-carbon Biological nitrogen removal Denitrification

Pushing the frontiers: Chip-based detection based on micro-and nano-structures

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Chinese Chemical Letters 2024年第4期35卷 86-98页

作者： Meihui liu Xinyuan Zhou Xiao Li Zhenjie Xue tie Wang Tianjin Key Laboratory of Life and Health Detection Life and Health Intelligent Research InstituteTianjin University of TechnologyTianjin 300384China

Changes in trace substances in human metabolites, which are related to disease processes and health status, can serve as chemical markers for disease diagnosis and symptom monitoring. Real-time online detection is an inevitable trend for the future of health monitoring, and the construction of chips for detection faces major challenges. The response of sensors often fails to meet the requirements for chipbased detection of trace substances due to the low efficiency of interfacial heterogeneous reactions, necessitating a rational design approach for micro-and nano-structures to improve sensor performance with respect to sensitivity and detection limits. This review focuses on the influence of micro-and nanostructures that used in chip on sensing. Firstly, this review categorizes sensors into chemiresistors, electrochemical sensors, fluorescence sensors, and surface enhanced Raman scattering(SERS) sensors based on their sensing principle, which have significant applications in disease diagnosis. Subsequently, commencing from the application requirements in the field of sensing, this review focuses on the different structures of nanoparticle(NP) assemblies, including wire, layered, core-shell, hollow, concave and deformable structures. These structures change in the size, shape, and morphology of conventional structures to achieve characteristics such as ordered alignment, high specific surface area, space limitation,vertical diffusion, and swaying behavior with fluid, thereby addressing issues such as poor signal transmission efficiency, inadequate adsorption and capture capacity, and slow mass transfer speed during sensing. Finally, the design direction of micro-and nano-structures, and possible obstacles and solutions to promote chip-based detection have been discussed. It is hope that this article will inspire the exploration of interface micro-and nano-structures modulated sensing methods.

关键词： Chip-based detection Micro-and nano-structures Real-time online detection Sensing Health monitoring

Cognitive Jammers Assisted Covert Communication in Cognitive Radio Networks

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China Communications 2024年第9期21卷 75-89页

作者： liu Changjun Shi Jia tie Zhuangzhuang Wang Yongchao The State Key Laboratory of Integrated Services Networks Xidian UniversityXi’an 710071China

In this work,we investigate the covert communication in cognitive radio(CR)networks with the existence of multiple cognitive jammers(CJs).Specifically,the secondary transmitter(ST)helps the primary transmitter(PT)to relay information to primary receiver(PR),as a reward,the ST can use PT's spectrum to transmit private information against the eavesdropper(Eve)under the help of one selected cognitive jammer(CJ).Meanwhile,we propose three jammer-selection schemes,namely,link-oriented jammer selection(LJS),min-max jammer selection(MMJS)and random jammer selection(RJS).For each scheme,we analyze the average covert throughput(ACT)and covert outage probability(COP).Our simulation results show that CJ is helpful to ST's covert communication,the expected minimum detection error probability and ACT can be significantly improved with the increase of false alarm of ***,the LJS scheme achieves best performance in ACT and COP,followed by RJS scheme,and MMJS scheme shows the worst performance.

关键词： cognitive jammer cognitive radio covert communication performance analysis

A Composite Elastomer with Photo-responsive Shape Memory and Programmable Hygroscopic Actuation Functionalities

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Chinese Journal of Polymer Science 2024年第10期42卷 1470-1478,I0009页

作者： Xiang-Xi Cui Li Shang Zhong-Wen liu Zhao-tie liu Jin-Qiang Jiang Guo Li Key Laboratory of Syngas Conversion of Shaanxi Province School of Chemistry and Chemical EngineeringShaanxi Normal UniversityXi’an710062China

Developing hydroscopic actuators with simultaneous high elasticity,shape programmability and tunable actuating behaviors are highly desired but still *** this study,we propose an orthogonal composite design to develop such a *** developed composite elastomer comprises carboxyl group-grafted polystyrene-block-poly(ethylene-co-butylene)-block-polystyrene(SEBS-g-COOH)as the elastic substrate,and a synthesized azobenzene derivative as the functional filler(Azo12).By surface treatment using acidic and base solutions,the carboxyl groups on the surface can reversibly transform into carboxylate groups,which render the composite tunable hygroscopic actuating *** another aspect,the added filler undergoes trans-to-cis isomerization when exposed to UV light irradiation,leading to liquefaction of the crystalline aggregates formed by Azo12 *** liquefied Azo12 molecules can autonomously resotre their trans form and reform the crystalline *** reversible change in crystralline structure is utilized to realize the shape memory property,and 5 wt%of Azo12addition is adequate for the composite to exhibit photo-responsive shape memory behavior without compromising much of the *** regualtion of external geometry by shape memory effect is effective in altering the actuating *** proposed method can be extend to designing different composites with the demonstrated functionalities.

关键词： Actuator Shape memory Photo-responsive Hygroscopic responsive Azobenzene

Stable,intense supercontinuum light generation at 1 kHz by electric field assisted femtosecond laser filamentation in air

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Light(Science & Applications) 2024年第2期13卷 354-365页

作者： Yaoxiang liu Fukang Yin tie-Jun Wang Yuxin Leng ruxin Li Zhizhan Xu See Leang Chin State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine Mechanics and CAS Center for Excellence in Ultra-intense Laser ScienceChinese Academy of SciencesShanghaiChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina Centre d’Optique Photonique et Laser(COPL)and Département de physiquede génie physique et d’optiqueUniversitéLavalQuébecQuébecCanada

Supercontinuum(SC)light source has advanced ultrafast laser spectroscopy in condensed matter science,biology,physics,and *** to the frequently used photonic crystal fibers and bulk materials,femtosecond laser filamentation in gases is damage-immune for supercontinuum generation.A bottleneck problem is the strong jitters from filament induced self-heating at kHz repetition rate *** demonstrated stable kHz supercontinuum generation directly in air with multiple mJ level pulse *** was achieved by applying an external DC electric field to the air plasma *** pointing jitters of the 1 kHz air filament induced SC light were reduced by more than 2 *** stabilized high repetition rate laser filament offers the opportunity for stable intense SC generation and its applications in air.

关键词： intense repetition light

Hole mobility enhancement in monolayer WSe2 p-type transistors through molecular doping

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Science China(Information Sciences) 2024年第6期67卷 207-213页

作者： Shiyuan liu Xiong XIONG Xin WANG Xinhang SHI ru HUANG Yanqing WU School of Integrated Circuits and Beijing Advanced Innovation Center for Integrated Circuits Peking University Wuhan National High Magnetic Field Center and School of Integrated Circuits Huazhong University of Science and Technology

Two-dimensional （2D） transition metal dichalcogenide （TMDC） semiconductor materials exhibit extraordinary electrical properties,holding promise for the realization of next-generation complementary metal-oxide-semiconductor （CMOS） devices at ultimate ***,constrained by effective device doping strategies,the hole mobility and device performance of tungsten diselenide （WSe2） p-type transistors,especially monolayer chemical vapor deposition （CVD）-grown WSe2,have not met *** this paper,an effective performance enhancement of monolayer WSe2p-type transistor was achieved through a molecular doping *** monolayer WSe2directly on SiO2back-gated substrates and leveraging energy band alignment design,4-nitrobenzenediazonium tetrafluoroborate （4-NBD） molecular dopant with a concentration of 10 m M was utilized to modulate the Fermi level position of monolayer WSe2for hole *** devices demonstrated a more than 98%increase in hole mobility,reaching up to 97 cm2·V-1·s-1while maintaining the current on/off ratio of *** p-type WSe2transistors with 1μm channel length exhibit a high drive current surpassing 176μA·μm-1,exceeding previous CVD-WSe2devices with similar channel *** straightforward and effective approach to improving the electrical performance of WSe2transistors paves the way for advanced logic technologies based on transition metal dichalcogenide semiconductors.

关键词： CVD-grown WSe$_2$ molecular doping 4-NBD p-type transistors hole mobility

Modulating charge separation and transfer for high-performance photoelectrodes via built-in electric field

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1126-1146页

作者： Houyan Cheng Peng liu Yuntao Cui ru Ya Yuxiang Hu Jinshu Wang Key Laboratory of Advanced Functional Materials of Education Ministry of China Faculty of Engineering and ManufacturingBeijing University of TechnologyBeijing 100124China Key Laboratory of Cryogenic Science and Technology and Beijing Key Lab of Cryo-Biomedical Engineering Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China Inner Mongolia Academy of Science and Technology Hohhot 010020China

Constructing a built-in electric field has emerged as a key strategy for enhancing charge separation and transfer,thereby improving photoelectrochemical ***,considerable efforts have been devoted to this *** review systematically summarizes the impact of built-in electric fields on enhancing charge separation and transfer mechanisms,focusing on the modulation of built-in electric fields in terms of depth and ***,mechanisms and tuning strategies for built-in electric fields are ***,the state-of-the-art works regarding built-in electric fields for modulating charge separation and transfer are summarized and categorized according to surface and interface ***,current strategies for constructing bulk built-in electric fields in photoelectrodes are explored,and insights into future developments for enhancing charge separation and transfer in high-performance photoelectrochemical applications are provided.

关键词： photoelectrochemical water splitting bulk built-in electric field cation intercalation charge separation and transfer