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Supercapacitor electrode based on few-layer h-BNNSs/rGO composite for wide-temperature-range operation with robust stable cycling performance 预览
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作者 Tao Yang Hui-juan Liu +4 位作者 Fan Bai En-hui Wang Jun-hong Chen Kuo-Chih Chou Xin-mei Hou 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2020年第2期220-231,共12页
Currently,developing supercapacitors with robust cycle stability and suitability for wide-temperature-range operations is still a huge challenge.In the present work,few-layer hexagonal boron nitride nanosheets(h-BNNSs... Currently,developing supercapacitors with robust cycle stability and suitability for wide-temperature-range operations is still a huge challenge.In the present work,few-layer hexagonal boron nitride nanosheets(h-BNNSs)with a thickness of 2−4 atomic layers were fabricated via vacuum freeze-drying and nitridation.Then,the h-BNNSs/reduced graphene oxide(rGO)composite were further prepared using a hydrothermal method.Due to the combination of two two-dimensional(2D)van der Waals-bonded materials,the as-prepared h-BNNSs/rGO electrode exhibited robustness to wide-temperature-range operations from−10 to 50℃.When the electrodes worked in a neutral aqueous electrolyte(1 M Na2SO4),they showed a great stable cycling performance with almost 107%reservation of the initial capacitance at 0℃ and 111% at 50℃ for 5000 charge−discharge cycles. 展开更多
关键词 few-layer hexagonal boron nitride wide-temperature-range operation cycling performance
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In-situ formation of MOF derived mesoporous Co3N/amorphous N-doped carbon nanocubes as an efficient electrocatalytic oxygen evolution reaction
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作者 Bong Kyun Kang Seo Young Im +8 位作者 Jooyoung Lee Sung Hoon Kwag Seok Bin Kwon SintayehuNibret Tiruneh Min-Jun Kim Jung Ho Kim Woo Seok Yang Byungkwon Lim Dae Ho Yoon 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第7期1605-1611,共7页
The suitable materials,metal nitrides,are a promising class of electrocatalyst materials for a highly efficient oxygen evolution reaction (OER) because they exhibit superior intrinsic conductivity and have higher sust... The suitable materials,metal nitrides,are a promising class of electrocatalyst materials for a highly efficient oxygen evolution reaction (OER) because they exhibit superior intrinsic conductivity and have higher sustainability than oxide-based materials.To our knowledge,for the first time,we report a designable synthesis of three-dimensional (3D) and mesoporous Co3N@ amorphous N-doped carbon (AN-C) nanocubes (NCs) with well-controlled open-framework structures via monodispersed Co3[Co(CN)6]2 Prussian blue analogue (PBA) NC precursors using in situ nitridation and calcination processes.Co3N@AN-C NCs (2 h) demonstrate better OER activity with a remarkably low Tafel plot (69.6 mV-dec-1),low overpotential of 280 mV at a current density of 10 mA-crrf2.Additionally,excellent cycling stability in alkaline electrolytes was exhibited without morphological changes and voltage elevations,superior to most reported hierarchical structures of transition-metal nitride particles.The presented strategy for synergy effects of metal-organic frameworks (MOFs)-derived transition-metal nitrides-carbon hybrid nanostructures provides prospects for developing high-performance and advanced electrocatalyst materials. 展开更多
关键词 TRANSITION-METAL nitride metal organic framework MESOPOROUS oxygen evaluation reaction alkaline water ELECTROLYSIS
Single titanium-oxide species implanted in 2D g-CsN4 matrix as a highly efficient visible-light CO2 reduction photocatalyst
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作者 Shangfeng Tang Xuepeng Yin +2 位作者 Guanyu Wang Xiuli Lu Tongbu Lu 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第2期457-462,共6页
A visible-light-response, efficie nt and robust photo-catalyst for CO2 reduction is highly desirable. Herein, we demonstrate that single titanium-oxide species impla nted in two-dime nsion al (2D) graphitic carb on n ... A visible-light-response, efficie nt and robust photo-catalyst for CO2 reduction is highly desirable. Herein, we demonstrate that single titanium-oxide species impla nted in two-dime nsion al (2D) graphitic carb on n itride (g-C3N4) matrix (2D TiO-CN) can efficie ntly photo-catalyze the reduction of CO2 to CO under the irradiation of visible light. The synergistic interaction between single titanium oxide species and g-C3N4 in 2D TiO-CN not only enhances the separation of photo-excited charges, but also results in visible light response of single titanium-oxide species, realizing high activity of CO2 photo-reduction with extremely high CO generation rate of 283.9 pmol·h^-1·g^-1, 5.7, 6.8 and 292.2 times larger than those of TQ2/CN hybrid material, CN and commercial TiO2, respectively. Time-resolved fluoresce nee and electron spin resonance spectroscopy revealed the catalytic mechanism of the fabricated 2D TiO-CN photocatalysts for CO2 reduction. 展开更多
关键词 SINGLE atom catalyst graphitic carbon nitride two-dimensional (2D) PHOTOCATALYSTS VISIBLE-LIGHT CO2 REDUCTION
Band gap tuning of g-C3N4via decoration with AgCl to expedite the photocatalytic degradation and mineralization of oxalic acid
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作者 Hanlu Shi Rui He +3 位作者 Lei Sun Gang Cao Xiangjuan Yuan Dongsheng Xia 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第10期1-12,共12页
A series of functional organic-metal AgCl-decorated graphitic carbon nitride(AgCl-CNx)composites were synthesized and applied for the degradation of oxalic acid(OA)under visible light.The highest photocatalytic activi... A series of functional organic-metal AgCl-decorated graphitic carbon nitride(AgCl-CNx)composites were synthesized and applied for the degradation of oxalic acid(OA)under visible light.The highest photocatalytic activity was achieved with AgCl decoration ratio of1.0(denoted as AgCl-CN1.0).The pseudo-first-order constant for OA degradation was 0.0722min-1 with the mineralization efficiency of 90.80%after 60 min reaction in the photocatalytic process with AgCl-CN1.0.A variety of characterization techniques including BrunauerEmmett-Teller,X-ray diffraction,scanning electron microscope,transmission electron microscopy,X-ray photoelectron spectroscopy,Fourier transform infrared spectra,ultraviolet-visible diffuse reflectance spectra,photoluminescence,and Mott-Schottky were utilized to elucidate the physicochemical,microstructure,and optical properties contributing to the improvement of the photocatalytic performance.The results showed that AgClCN1.0had an oblate flaky erythrocyte-like structure with a moderate band gap energy of~3.00 eV.In addition,the effects of the key parameters(i.e.,AgCl-CN1.0 dosage,initial OA concentration,solution pH,and presence of natural organic matter)on OA degradation were systematically investigated.Radical scavenger experiments indicated that photogenerated holes,electrons,superoxide anion radicals,and hydroxyl radicals were the dominant reactive species.Moreover,AgCl-CN1.0 exhibited excellent stability and reusability for OA degradation without detectable Ag+release in the solution over multiple reaction cycles.The efficient OA mineralization could be mainly ascribed to the moderate specific surface area,increased numbers of active sites,and effective interfacial charge transfer of AgCl-CN1.0.Overall,the AgCl-CN1.0 composite was demonstrated to be a highly efficient,stable,and recoverable photocatalyst. 展开更多
关键词 AGCL Graphitic carbon NITRIDE PHOTOCATALYTIC degradation Oxalic acid Mechanism
The fabrication of AlN by hydride vapor phase epitaxy 预览
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作者 Maosong Sun Jinfeng Li +1 位作者 Jicai Zhang Wenhong Sun 《半导体学报:英文版》 EI CAS CSCD 2019年第12期70-81,共12页
Aluminum nitride(AlN)is the promising substrates material for the epitaxial growth ofⅢ-nitrides devices,such as high-power,high-frequency electronic,deep ultraviolet optoelectronics and acoustic devices.However,it is... Aluminum nitride(AlN)is the promising substrates material for the epitaxial growth ofⅢ-nitrides devices,such as high-power,high-frequency electronic,deep ultraviolet optoelectronics and acoustic devices.However,it is rather difficult to obtain the high quality and crack-free thick AlN wafers because of the low surface migration of Al adatoms and the large thermal and lattice mismatches between the foreign substrates and AlN.In this work,the fabrication of AlN material by hydride vapor phase epitaxy(HVPE)was summarized and discussed.At last,the outlook of the production of AlN by HVPE was prospected. 展开更多
关键词 hydride vapor phase epitaxy aluminum nitride templates free standing substrate
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Amine-rich carbon nitride nanoparticles:Synthesis,covalent functionalization with proteins and application in a fluorescence quenching assay
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作者 Gabriele Capilli Simone Cavalera +4 位作者 Laura Anfossi Cristina Giovannoli Marco Minella Claudio Baggiani Claudio Minero 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第8期1862-1870,共9页
Carbon nitride nanoparticles (CNNPs) have been employed as fluorescent sensing tools owing to their unique features, e.g. low cost production, high stability in water and high photoluminescence quantum yield. Here, an... Carbon nitride nanoparticles (CNNPs) have been employed as fluorescent sensing tools owing to their unique features, e.g. low cost production, high stability in water and high photoluminescence quantum yield. Here, an easy and versatile synthetic approach was exploited to design fluorescent nanoparticles with surface functionalities suitable for covalent binding to bioligands. High hydrophilic, brightly fluorescent CNNPs, rich of superficial amines, were obtained from the thermal condensation of urea and lysine (CNNP^Lys) and by tuning the precursor ratio and the heating time. Structure and size of the functionalized nanoparticles were characterized through infrared (IR) spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS). Their optical properties were studied by ultraviolet-visible (UV-Vis) and fluorescence spectroscopy. The superficial primary amino groups, furnished by the lysine co-precursor, enabled for covalently linking CNNP^Lys to model proteins. The CNNP^Lys-protein conjugates excited under UV irradiation emit in the 400-450 nm visible range (quantum yield 24%). The applicability of CNNP^Lys as novel fluorescent probes was demonstrated by a fluorescence quenching assay, in which gold nanoparticles (GNPs) were attached to Staphylococcal protein A and employed to quench the CNNP^Lys fluorescence by Forster resonant energy transfer (FRET). The quenching occurred upon formation of the specific binding between the GNP-linked protein A and CNNP^Lys-tagged immunoglobulins, while the inhibition of the binding resulted in the recovery of CNNP^Lys luminescence. The synthetic strategy, based on combining a "conjugated polymer"-forming unit (urea) and a co-precursor able to provide the desired functional group (lysine), allows designing innovative materials for the development of new generation fluorescence biosensors in which easily functionalized fluorophores are needed. 展开更多
关键词 FLUORESCENT probe carbon NITRIDE NANOPARTICLES QUENCHING ASSAY FLUORESCENT materials g-C3N4 FORSTER resonant energy transfer (FRET)
C–C formation mediated by photoinduced electrons from crystallized carbon nitride nanobelts under visible light irradiation 预览
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作者 Qiaohui Jia Sufen Zhang Quan Gu 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第3期152-161,共10页
Crystal structure and crystallinity of carbon nitride support, size and dispersity of active-metal nanopar-ticles (NPs), and surface engineering of composites have great roles in generation and separation of photogene... Crystal structure and crystallinity of carbon nitride support, size and dispersity of active-metal nanopar-ticles (NPs), and surface engineering of composites have great roles in generation and separation of photogenerated charge carries and photocatalyzed organic reactions for the conversion of solar energy into chemical energy. Herein, we deposited well-dispersed Pd NPs with small size on crystallized car-bon nitride (CN-C) to construct a Schottky-type Pd/CN–C hybrid for photocatalyzed Ullmann C–C homo-coupling of aryl halides under visible light irradiation at room temperature. Compared to Pd NPs sup-ported g-C3N4 (Pd/g-C3N4), Pd/CN–C exhibits excellent visible light photocatalytic activity for Ullmann C–C coupling of aryl halides due to high crystallinity of CN–C support, high dispersion and smaller size of Pd NPs, and the interfacial heterojunction of Pd/CN–C. Upon visible light irradiation, more photogen-erated electrons from CN–C flow across the Schottky junction to metallic Pd and trigger the Ullmann C–C coupling of aryl halides. The photogenerated holes on CN–C surface are captured by a protic solvent (such as EtOH). In the presence of base K2CO3, the solvent undergoes dissociation, dehydrogenation, and finally can be oxidized by captured photogenerated holes. Moreover, Pd/CN–C has general applicability for various substrates and shows excellent stability and reusability for more than nine cycles. 展开更多
关键词 Crystallized carbon NITRIDE Pd NANOPARTICLES PHOTOCATALYST C–C coupling ULLMANN reaction
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Cobalt atoms dispersed on hierarchical carbon nitride support as the cathode electrocatalyst for high-performance lithium-polysulfide batteries
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作者 Jialing Wu Junmei Chen +6 位作者 Yang Huang Kun Feng Jun Deng Wei Huang Yunling Wu Jun Zhong Yanguang Li 《科学通报:英文版》 SCIE EI CSCD 2019年第24期1875-1880,共6页
Lithium-sulfur batteries are promising candidates for next-generation energy storage but are confronted with several challenges. One of the possible solutions is to design proper cathode electrocatalysts to accelerate... Lithium-sulfur batteries are promising candidates for next-generation energy storage but are confronted with several challenges. One of the possible solutions is to design proper cathode electrocatalysts to accelerate the redox interconversion of solvated polysulfide intermediates. Herein, we report cobalt atoms dispersed on hierarchical carbon nitride support as an effective cathode electrocatalyst for lithium-polysulfide batteries. The electrocatalyst material is prepared from the simple reaction between melamine and cyanuric acid in the presence of Co^2+, followed by the Ar annealing. The product has a unique hierarchical structure consisting of many thin and porous C3 N4 nanosheets finely dispersed with Co atoms. The atomic dispersion of Co species is confirmed by X-ray absorption experiments.Electrochemical measurements reveal that it can promote the interconversion of polysulfides. As a result,batteries using this cathode electrocatalyst achieve large capacity($1400 mAh/g at 1.6 mA/cm^2), good rate performance($800 mAh/g at 12.8 mA/cm^2) and impressive cycling stability under different current densities and different sulfur loadings. 展开更多
关键词 Li-polysulfide battery Cathode electrocatalyst Carbon nitride Cobalt single atom
钼(钨)基氮化物硬质及超硬涂层的微观结构及综合性能 预览
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作者 蔡立辉 张涛 +1 位作者 方前锋 杨俊峰 《科技资讯》 2019年第31期48-51,54,共5页
利用直流反应磁控溅射技术,在不锈钢和硅衬底上分别制备了三元MoCN、MoSiN、MoAlN、MoWN、WTaN及四元MoAlSiN、MoSiCN、WSiCN涂层。利用XRD、XPS、TEM、SEM等方法分析了薄膜的微观结构和表面形貌;利用纳米压痕仪、划痕仪、摩擦磨损测试... 利用直流反应磁控溅射技术,在不锈钢和硅衬底上分别制备了三元MoCN、MoSiN、MoAlN、MoWN、WTaN及四元MoAlSiN、MoSiCN、WSiCN涂层。利用XRD、XPS、TEM、SEM等方法分析了薄膜的微观结构和表面形貌;利用纳米压痕仪、划痕仪、摩擦磨损测试仪、以及热重分析法测试了薄膜的硬度、膜基结合力、摩擦系数、及抗氧化温度。结果表明四元MoSiCN、WSiCN涂层具有更加优异的综合性能,可望向工业领域转化。 展开更多
关键词 磁控溅射 硬质涂层 氮化物
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PEALD-deposited crystalline GaN films on Si(100) substrates with sharp interfaces
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作者 刘三姐 何荧峰 +6 位作者 卫会云 仇鹏 宋祎萌 安运来 阿布度-拉赫曼 彭铭曾 郑新和 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第2期376-382,共7页
Polycrystalline gallium nitride(GaN) thin films were deposited on Si(100) substrates via plasma-enhanced atomic layer deposition(PEALD) under optimal deposition parameters. In this work, we focus on the research of th... Polycrystalline gallium nitride(GaN) thin films were deposited on Si(100) substrates via plasma-enhanced atomic layer deposition(PEALD) under optimal deposition parameters. In this work, we focus on the research of the GaN/Si(100)interfacial properties. The x-ray reflectivity measurements show the clearly-resolved fringes for all the as-grown GaN films, which reveals a perfectly smooth interface between the GaN film and Si(100), and this feature of sharp interface is further confirmed by high resolution transmission electron microscopy(HRTEM). However, an amorphous interfacial layer(~ 2 nm) can be observed from the HRTEM images, and is determined to be mixture of Ga_xO_y and GaN by xray photoelectron spectroscopy. To investigate the effect of this interlayer on the GaN growth, an AlN buffer layer was employed for GaN deposition. No interlayer is observed between GaN and AlN, and GaN shows better crystallization and lower oxygen impurity during the initial growth stage than the GaN with an interlayer. 展开更多
关键词 GALLIUM NITRIDE PEALD SHARP interface x-ray REFLECTIVITY high resolution transmission electron microscopy
N—甲基甲酰胺+吡咯+烷烃三元体系相平衡测量和相关性研究 预览
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作者 察兴昌 《化工设计通讯》 CAS 2019年第5期164-165,共2页
为了从柴油中分离出氮化合物,选择N-甲基甲酰胺作为萃取过程的萃取剂。在常温(298.15K)常压下测量{NMF+吡咯+烷烃}的三元体系的液-液平衡数据。四个三元系统的三角图都被归于Trey Bal的I型系统,属于一个部分可混溶的系统。同时,使用NRTL... 为了从柴油中分离出氮化合物,选择N-甲基甲酰胺作为萃取过程的萃取剂。在常温(298.15K)常压下测量{NMF+吡咯+烷烃}的三元体系的液-液平衡数据。四个三元系统的三角图都被归于Trey Bal的I型系统,属于一个部分可混溶的系统。同时,使用NRTL和UNIQUAC活度系数模型对实验数据进行相关,UNIQUAC模型较NRTL显示出更好的相关性。此外,基于实验数据计算分配系数和选择性,以研究NMF对吡咯和吲哚的萃取能力。 展开更多
关键词 液-液平衡 N-甲基甲酰胺 吡咯 正己烷 正庚烷 正癸烷 正十二烷 氮化物
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Nitridation-Etch of Silicon Oxide in Fluorocarbon/Nitrogen Plasma:A Computational Study 预览
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作者 Du Zhang Yu-Hao Tsai +1 位作者 Hojin Kim Mingmei Wang 《微电子制造学报》 2019年第1期19-26,共8页
The continually increasing number of silicon oxide(SiO2)and nitride(Si3N4)layers in 3D-NAND offers both motivations and challenges for developing all-in-one plasma etch solutions for etching SiO2 and Si3N4 at a select... The continually increasing number of silicon oxide(SiO2)and nitride(Si3N4)layers in 3D-NAND offers both motivations and challenges for developing all-in-one plasma etch solutions for etching SiO2 and Si3N4 at a selectivity near unity while maintaining a high etch rate.This is essential for a simultaneous etch landing of all holes that differ in their respective SiO2 and Si3N4 layer numbers and dummy SiO2 thickness,and for a quick wafer turnover.Surface modification may be employed to make the SiO2 and Si3N4 layers closer in composition,either by converting Si3N4 to oxynitride(SiOxNy)[J.Micro.Manuf.1,20180102(2018)],or by converting SiO2 to SiOxNy,presented in this paper.We computationally demonstrate the feasibility of a nitridation-etch process for SiO2 in fluorocarbon/nitrogen-based plasma with molecular dynamics(MD)and quantum chemistry(QC)simulations.First,the nitridation via ion implantation is observed with MD,which replaces surface oxygen by nitrogen.Second,the reactions involving oxygen and silicon volatilization are energetically favorable per QC calculations.Finally,both MD and QC simulations indicate a synergy between fluorine and nitrogen etchants by enhancing each other’s reactivity with the SiO2 surface.These atomistic surface reaction mechanisms will offer insight for the development of robust engineering solutions for 3D-NAND fabrication. 展开更多
关键词 3D-NAND oxide NITRIDE OXYNITRIDE plasma ETCH molecular dynamics quantum chemistry
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Monolithic crystalline silicon solar cells with SiNx layers doped with Tb3+ and Yb3+ rare-earth ions
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作者 Ing-Song Yu Shao-Chun Wu +3 位作者 Lucile Dumont Julien Cardin Christophe Labbé Fabrice Gourbilleau 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2019年第5期515-519,共5页
In this study, we propose the fabrication of monolithic crystalline silicon solar cells with Tb3+ and Yb3+-doped silicon nitride(SiNx) layers by low-cost screen-printing methods. The performances of c-Si solar cells c... In this study, we propose the fabrication of monolithic crystalline silicon solar cells with Tb3+ and Yb3+-doped silicon nitride(SiNx) layers by low-cost screen-printing methods. The performances of c-Si solar cells can be enhanced by rare-earth ions doped SiNx layers via the mechanism of spectrum conversion.These SiNx doped and codoped thin films were deposited by reactive magnetron co-sputtering and integrated as the antireflection coating layers in c-Si solar cells. The characterizations of SiNx, SiNx:Tb3+ tand SiNx:Tb3+-Yb3+ thin films were conducted by means of photoluminescence, Rutherford backscattering spectroscopy, Ellipsometry spectroscopy and Fourier transform infrared measurements. Their composition and refractive index was optimized to obtain good anti-reflection coating layer for c-Si solar cells.Transmission electron microscopy performs the uniform coatings on the textured emitter of c-Si solar cells. After the metallization process, we demonstrate monolithic c-Si solar cells with spectrum conversion layers, which lead to a relative increase by 1.34% in the conversion efficiency. 展开更多
关键词 Crystalline SILICON solar cell Spectrum conversion SILICON NITRIDE Down-shifting RARE-EARTH ion ANTI-REFLECTION coating
Facile and efficient fabrication of g-C3N4 quantum dots for fluorescent analysis of trace copper(Ⅱ) in environmental samples
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作者 Qin Liu Debin Zhu +2 位作者 Manli Guo Ying Yu Yujuan Cao 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第9期1639-1642,共4页
The facile preparation of g-C3N4 QDs with high fluorescent performance has become an important direction in the last decade. Herein, we develop a facile, rapid approach to synthesize highly fluorescent QDs based on re... The facile preparation of g-C3N4 QDs with high fluorescent performance has become an important direction in the last decade. Herein, we develop a facile, rapid approach to synthesize highly fluorescent QDs based on recrystallization and ultrasonic exfoliation. Size-controllable graphitic carbon nitride(gC3N4) QDs can be obtained from the precursor of recrystallized dicyandiamide, only 90 min is needed and the size of QDs is adjusted from 5 nm to 200 nm by controlling the ultrasonic time. Moreover, better fluorescent efficiency is also obtained comparing to traditional g-C3N4 QDs. The obtained g-C3N4 QDs responds to Cu(Ⅱ) in the 0.5 nmol/L to 30 μmol/L concentration range, with a 0.3 nmol/L detection limit.The method was applied to the determination of Cu(Ⅱ) in different environmental water samples. 展开更多
关键词 Graphitic carbon NITRIDE Quantum DOTS Recrystallized FLUORESCENT ANALYSIS Copper(Ⅱ)
Intermodal frequency generation in silicon-rich silicon nitride waveguides
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作者 C.LACAVA T.DOMINGUEZ BUCIO +6 位作者 A.Z.KHOKHAR P.HORAK Y.JUNG F.Y.GARDES D.J.RICHARDSON P.PETROPOULOS F.PARMIGIANI 《光子学研究:英文版》 CSCD 2019年第6期615-621,共7页
Dispersion engineering in optical waveguides allows applications relying on the precise control of phase matching conditions to be implemented. Although extremely effective over relatively narrow band spectral regions... Dispersion engineering in optical waveguides allows applications relying on the precise control of phase matching conditions to be implemented. Although extremely effective over relatively narrow band spectral regions,dispersion control becomes increasingly challenging as the bandwidth of the process of interest increases.Phase matching can also be achieved by exploiting the propagation characteristics of waves exciting different spatial modes of the same waveguide. Phase matching control in this case relies on achieving very similar propagation characteristics across two, and even more, waveguide modes over the wavelengths of interest, which may be rather far from one another. We demonstrate here that broadband(>40 nm) four-wave mixing can be achieved between pump waves and a signal located in different bands of the communications spectrum(separated by50 nm) by exploiting interband nonlinearities. Our demonstration is carried out in the silicon-rich silicon nitride material platform, which allows flexible device engineering, allowing for strong effective nonlinearity at telecommunications wavelengths without deleterious nonlinear-loss effects. 展开更多
关键词 Intermodal FREQUENCY silicon-rich silicon NITRIDE WAVEGUIDES
Mechanism of Ti/Al/Ni/Au ohmic contacts to AlGaN/GaN heterostructures via laser annealing
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作者 侯明辰 谢刚 盛况 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第3期342-346,共5页
The physical mechanisms of Ti/Al/Ni/Au ohmic contacts to AlGaN/GaN heterostructures by laser annealing and rapid thermal annealing are systematically investigated. The microstructures indicate that a better surface mo... The physical mechanisms of Ti/Al/Ni/Au ohmic contacts to AlGaN/GaN heterostructures by laser annealing and rapid thermal annealing are systematically investigated. The microstructures indicate that a better surface morphology and an intact contact interface are formed after laser annealing. None of the TiN alloy spikes are formed at the interface of the laser annealing sample. The experimental results show that the current transport mechanism through the ohmic contact after laser annealing is different from the conventional spike mechanism, and it is dominated by thermionic field emission. 展开更多
关键词 GALLIUM NITRIDE ohmic CONTACTS laser ANNEALING current transport MECHANISM
Hexagonal boron nitride nanosheet for effective ambient N2 fixation to NH3
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作者 Ya Zhang Huitong Du +10 位作者 Yongjun Ma Lei Ji Haoran Guo Ziqi Tian Hongyu Chen Hong Huang Guanwei Cui Abdullah M. Asiri Fengli Qu Liang Chen Xuping Sun 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第4期919-924,共6页
Industrial production of NH3 from N2 and H2 significantly relies on Haber-Bosch process,which suffers from high energy consume and CO2 emission.As a sustainable and environmentally-benign alternative process,electroch... Industrial production of NH3 from N2 and H2 significantly relies on Haber-Bosch process,which suffers from high energy consume and CO2 emission.As a sustainable and environmentally-benign alternative process,electrochemical artificial N2 fixation at ambient conditions,however,is highly required efficient electrocatalysts.In this study,we demonstrate that hexagonal boron nitride nanosheet (h-BNNS) is able to electrochemically catalyze N2 to NH3.In acidic solution,h-BNNS catalyst attains a high NH3 formation rate of 22.4 μg·h-1·mg-1cat.and a high Faradic efficiency of 4.7% at-0.75 V vs.reversible hydrogen electrode,with excellent stability and durability.Density functional theory calculations reveal that unsaturated boron at the edge site can activate inert N2 molecule and significantly reduce the energy barrier for NH3 fonmation. 展开更多
关键词 boron NITRIDE NANOSHEET N2 reduction reaction NH3 ELECTROSYNTHESIS AMBIENT conditions density functional theory
38CrMoAl钢螺杆氮化表面剥落原因分析
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作者 王得礼 林生秀 +1 位作者 刘金龙 陆建民 《物理测试》 CAS 2019年第5期38-42,共5页
在生产螺杆过程中,螺杆表面出现剥落麻点现象,通过宏观、扫描电镜、金相显微镜和光谱等方法对螺杆氮化表面剥落原因进行分析,结果表明:螺杆表面出现剥落麻点的原因是由于氮化处理前磨削至局部螺纹棱角处时温度偏高,使棱角处及其附近的... 在生产螺杆过程中,螺杆表面出现剥落麻点现象,通过宏观、扫描电镜、金相显微镜和光谱等方法对螺杆氮化表面剥落原因进行分析,结果表明:螺杆表面出现剥落麻点的原因是由于氮化处理前磨削至局部螺纹棱角处时温度偏高,使棱角处及其附近的表面及浅表层产生轻微的沿晶裂纹,在后续磨削过程中,棱角处易剥落形成麻点。 展开更多
关键词 麻点 脆性断裂 裂纹 脱碳层 氮化
The role of interstitial species upon the ammonia synthesis activity of ternary Fe–Mo–C(N)and Ni–Mo–C(N)phases 预览
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作者 Angela Daisley Justin S.J.Hargreaves 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第12期170-175,共6页
Fe3Mo3C has been prepared and its activity for ammonia synthesis was evaluated.As had been observed previously for Co3Mo3C,it was found to be inactive at 400℃.At 500℃activity developed and this can be related to the... Fe3Mo3C has been prepared and its activity for ammonia synthesis was evaluated.As had been observed previously for Co3Mo3C,it was found to be inactive at 400℃.At 500℃activity developed and this can be related to the substitution of lattice carbon by nitrogen.Application of a simple topotactic route to prepare Ni2Mo3C from Ni2Mo3N proved unsuccessful,with the resultant carbonitride formed under optimal synthesis conditions being active for ammonia synthesis at 400℃. 展开更多
关键词 NITRIDE Carbide CARBONITRIDE Ammonia Nickel Iron Molybdenum
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Comparative cyclic oxidation behaviour and effect of oxides on hardness of wear resistance coating alloys T-401 and T-900
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作者 Abdul Rehman Yang Liang +4 位作者 Mohammad Hassan Shirani Bidabadi Zheng Yu Chi Zhang Hao Chen Zhi-gang Yang 《钢铁研究学报:英文版》 SCIE EI CAS CSCD 2019年第10期1069-1079,共11页
The investigated alloys are newly developed Tribaloy alloys with enhanced crack and oxidation resistance over the traditional Tribaloy alloys.The cyclic oxidation performance and effects of complex oxides on the hardn... The investigated alloys are newly developed Tribaloy alloys with enhanced crack and oxidation resistance over the traditional Tribaloy alloys.The cyclic oxidation performance and effects of complex oxides on the hardness of cobaltbased Tribaloy alloys T-401(hypoeutectic)and T-900(hypereutectic)were assessed.The results showed that T-900 alloy has a lower oxidation rate as compared to T-401 alloy at 800 and 1000℃,which attributed to the formation of dense continuous Cr2O3 layer with an upper thinner continuous layer of CoCr2O4 and NiCr2O4 oxides.At 1000℃,T-401 alloy exhibited poor oxidation resistance due to severe spallation after 3 cycles(45 h).After oxidation,T-900 alloy exhibits 98%and 18%lower mass gain than T-401 alloy at 1000 and 800℃,respectively.For T-900 alloy,relationship between mass gain and thickness of oxide layer revealed that mass will increase 0.162 mg/cm2 for every 1-μm increase in the oxides thickness.Internal SiO2 oxide was observed at 800 and 1000℃for both alloys.However,the extent of internal Si oxides increased with increasing oxidation temperature from 800 to 1000℃.Consequently,internal oxidation of Si led to the formation of Laves phase-depleted region near oxide/alloy interface in T-900 alloy at 1000℃.Thus,hardness of T-900 alloy decreased from 618 to 392 HV beneath the oxide/alloy interface at 1000℃,whereas hardness of T-900 and T-401 alloys after cyclic oxidation test at 800℃increased from 618 to 855 and 519 to 685 HV,respectively. 展开更多
关键词 Tribaloy Hypoeutectic alloy Hypereutectic alloy Cyclic oxidation Depletion NITRIDE HARDNESS
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