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Synthesis, characterization, theoretical investigation, and properties of monoclinic-phase InWO4 hollow nanospheres

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Nano Research 2018年第9期11卷 4664-4672页

作者： Yuping wang Di wang Ying Xie guofeng wang Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education School of Chemistry and Materials ScienceHeilongjiang University Harbin 150080 China

As a newly discovered member of the ttmgstate famil3~ InWO4 hollow nanospheres with a monoclinic wolframite structure were synthesized successfully. The crystal phase of InWO4 was investigated via a combination of CASTEP geometric optimization and experimental simulation. InWO, has a space group of P2/c with two InWO, formula units per unit cell. The optimized cell dimensions are a = 5.16 A, b = 5.97 A, and c = 5.23 A, with a = 90°, β= 92.11°, 7 = 90°, giving a unit cell volume of 161.10 A^3, which is consistent with the experimental measurements. More importantly, InWO4 was a promising host material for different Ln^3＋（Ln = Eu and Yb/Er） ions. For InWO4：Yb^3＋/Er^3＋ excited at 980 nm, transitions from the ^4G11/2 （384 nm）, ^2H9/2 （411 nm）, and ^4F7/2 （487 nm） levels to the ground state （^4I15/2） of Er^3＋ were observed. In addition to the aforementioned properties, the InWO4 hollow nanospheres can be used to improve the performance of dye-sensitized solar cells, which is chiefly attributed to their light scattering.

关键词： InWO4 rare earth hollow nanospheres luminescence

Design and application of single-antenna GPS/accelerometers attitude determination system

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Journal of Systems Engineering and Electronics 2008年第2期19卷 220-227页

作者： He Jie Huang Xianlin wang guofeng Center for Control Theory and Guidance Technique Harbin Inst. of Technology Harbin 150001 P. R. China The Third Research Academy China Aerospace Science &~ Industry Corporation Beijing 100072 P. R. China

In view of the problem that the current single-antenna GPS attitude determination system can only determine the body attitude when the sideslip angle is zero and the multiantenna GPS/SINS integrated navigation system is of large volume, high cost, and complex structure, this approach is presented to determine the attitude based on vector space with single-antenna GPS and accelerometers in the micro inertial measurement unit （MIMU）. It can provide real-time and accurate attitude information. Subsequently, the single-antenna GPS/SINS integrated navigation system is designed based on the combination of position, velocity, and attitude. Finally the semi- physical simulations of single-antenna GPS attitude determination system and single-antenna GPS/SINS integrated navigation system are carried out. The simulation results, based on measured data, show that the single-antenna GPS/SINS system can provide more accurate navigation information compared to the GPS/SINS system, based on the combination of position and velocity. Furthermore, the single-antenna GPS/SINS system is characteristic of lower cost and simpler structure. It provides the basis for the application of a single-antenna GPS/SINS integrated navigation system in a micro aerial vehicle （MAV）.

关键词： single-antenna GPS attitude determination vector space accelerometer integrated navigation MAV.

Tunable multicolor luminescence in vanadates from yttrium to indium with enhanced luminous efficiency and stability for its application in WLEDs and indoor photovoltaics

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Nano Research 2023年第8期16卷 11486-11494页

作者： Yaoyang Zhang Jing Mao Peifen Zhu guofeng wang Key Laboratory of Functional Inorganic Material Chemistry Ministry of EducationSchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin 150080China Department of Electrical Engineering and Computer Science University of MissouriColumbiaMissouri 65211USA

The preparation of high-efficiency phosphor is the key to the construction of white light-emitting diode(WLED)devices and their application in indoor *** with YVO_(4),InVO_(4)is not suitable as the host material of lanthanide ions because of its strong ***,the work focused on combining the broadband emission from InVO_(4)and the red luminescence from YVO_(4):Eu^(3+)to obtain enhanced and stable multicolor *** band structure,density of state,and optical properties were studied by density functional *** spectral configuration of YVO_(4):In^(3+)/Eu^(3+)with(112)surface appears to be broadening and redshifts with increasing layer *** the In^(3+)concentration is 3.5 mol%,the YVO_(4):30%Eu^(3+)/In^(3+)emits the strongest *** Judd-Ofelt parameterΩ2 of YVO_(4):In^(3+)/Eu^(3+)increases with increaing In^(3+)concentration,indicating that the symmetry *** adjusting In^(3+)/Eu^(3+)contents,the YVO_(4):In^(3+)/Eu^(3+)not only can emit white light with a color rendering index of 95,but also can be used as high-efficiency red phosphor to build WLED devices with blue emitting N/Tb codoped carbon quantum dots(CQDs-N:Tb^(3+))and green emitting MOF:Tb^(3+)(MOF=metal organic framework),for which the color rendering index can also reach 95 and the color temperature is 5549 *** manufactured WLED devices were further used to excite the silicon solar cell and make it show good photoelectric characteristics.

关键词： luminescence enhancement multicolor stability density functional theory(DFT)calculation white light-emitting diodes(WLEDs) indoor photovoltaics

Nanoscale Morphology in Tensile Fracture of a Brittle Amorphous Ribbon

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Journal of Materials Science & Technology 2008年第5期24卷 745-749页

作者： Xifeng LI. Kaifeng ZHANG guofeng wang School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

The paper reports on the observation of nanoscale morphology on the tensile fracture surface of a brittle amorphous Fe-based ribbon. The formation of nanoscale damage cavity structure is a main characteristic morphology on the fracture surfaces. Approaching the ribbon boundary, these damage cavities assemble and form the nanoscale periodic corrugations, which are neither Wallner lines nor crack front waves. The periodic corrugations result from the interactions between the reflected elastic waves by the boundaries of amorphous ribbon and the stress fields of the crack tip.

关键词： Nanoscale periodic corrugation Damage cavity Tensile fracture Brittle amorphous ribbon

One-dimension carbon self-doping g-C3N4 nanotubes： Synthesis and application in dye-sensitized solar cells

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Nano Research 2018年第3期11卷 1322-1330页

作者： Xue Li Kai Pan Yang Qu guofeng wang Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education School of Chemistry and Materials Science Heilongjiang University Harbin 150080 China

One-dimensional carbon self-doping g-C3N4 nanotubes （CNT） with abundant communicating pores were synthesized via thermal polymerization of saturated or supersaturated urea inside the framework of a melamine sponge for the first time. A - 16% improvement in photoelectric conversion efficiency （η） is observed for the devices fabricated with a binary hybrid composite of the obtained CNT and TiO2 compared to pure TiO2 device. The result of EIS analysis reveals that the interfacial resistance of the TiO2-dye｜ I3^-/I- electrolyte interface of TiO2-CNT composite cell is much lower than that of pure TiO2 cell. In addition, the TiOa-CNT composite cell exhibits longer electron recombination time, shorter electron transport time, and higher charge collection efficiency than those of pure TiO2 cell. Systematic investigations reveal that the CNT boosts the light harvesting ability of the photovoltaic devices by enhancing not only the visible light absorption but also the charge separation and transfer.

关键词： g-C3N4 nanotube photoelectric conversion solar cells

CFD simulation of homogeneous reaction characteristics of dehydration of fructose to HMF in micro-channel reactors

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Chinese Journal of Chemical Engineering 2018年第6期26卷 1340-1349页

作者： Xin Zhang Hui Liu Amar Samb guofeng wang State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China Beijing Key Laboratory of Energy Environmental Catalysis Beijing University of Chemical Technology Beijing 100029 China China Tianchen Engineering Corporation (Beijing Branch) Beijing 100029 China

In this work the applicability of the micro-channel reactor technique to the production of promising platform chemical 5-hydroxymethyl furan(HMF) from fructose in aqueous solution is systemically investigated by performing CFD *** factors including solvents,residence time distribution of reaction mixtures,heat transfer conditions and micro-channel configurations are evaluated in terms of the reaction performance indices,i.e.,conversion of fructose,HMF selectivity and yield.A scale-up method from a single channel to a multiple channel reactor is also *** is demonstrated that:1) at the single channel scale,controlling residence times and temperature distribution of the reaction mixture within the channel is crucial for enhancing the reaction performance,while different channel configurations lead to marginal improvements;2) for the scaling-up of the reaction process,a reactor module containing 15 circular parallel channels could be used as module blocks,which can be stacked one by one to meet the required reactor performance and production *** present results show that micro-reactors are quite suitable for HMF production.

关键词： Fructose dehydration Micro-channel reactor Simulation Optimization

Pt/Y2O3：Eu3＋ composite nanotubes： Enhanced photoluminescence and application in dye-sensitized solar cells

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Nano Research 2016年第8期9卷 2338-2346页

作者： Mingqi Yu Jiamin Su guofeng wang Yadong Li Key Laboratory of Functional Inorganic Material Chemistry Ministry of Education School of Chemistry and Materials Science Heilongjiang University Harbin 150080 China Department of Chemistry Tsinghua University Beijing 100084 China

Y（OH）3：Eu3＋ nanotubes were synthesized using a facile hydrothermal method, and then, Pt particles were grown on the surface of the nanotubes using a combination of vacuum extraction and annealing. The resulting Pt/Y2O3：Eu3＋ composite nanotubes not only exhibited enhanced red luminescence under 255- or 468-nm excitation but could also be used to improve the efficiency of dye- sensitized solar cells, resulting in an efficiency of 8.33%, which represents a significant enhancement of 11.96% compared with a solar cell without the com- posite nanotubes. Electrochemical impedance spectroscopy results indicated that the interfacial resistance of the TiO2-dyel I3/I- electrolyte interface of the TiO2-Pt/Y203：Eu3~ composite cell was much smaller than that of a pure TiO2 cell. In addition, the TiO2-Pt/Y2O3：Eu3＋ composite cell exhibited a shorter electron transport time and longer electron recombination time than the pure TiO2 cell.

关键词： Pt/Y2O3:Eu3+ nanocrystals luminescence dye-sensitized solar cells

Cavitation Behavior during Superplastic Deformation of AZ31 Magnesium Alloy

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Journal of Materials Science & Technology 2005年第4期21卷 510-514页

作者： Kaifeng ZHANG Deliang YIN guofeng wang Wenbo HAN School of Materials Science and Engineering Harbin Institute of TechonologyHarbin 150001China

Superplasticity of AZ31 Mg alloy at the temperature range of 250-450℃ and stain rate range of 0.7×10^-3- 1.4×10^-1s^-1 was examined through uniaxial tensile *** microscopy （OM）and scanning electrom microscopy （SEM）were employed to investigate the morphology of cavities and surface relief near fracture surface,*** is shown that AZ31 Mg alloy starts to exhibit superplasticity for 300℃.The maximum elongation of 362.5% was obtained at 400℃ and strain rate of 0.7×10^-3s^-1,There exist many O-shaped cavities and filaments at the boundaries near fracture surface,The fracture of filaments results in intergranular cavity and the model for the formation of intergranular cavities is proposed .The growth of cavities is plasticity-controlled and the serrated boundaries of intergranular cavities agree with the results of surface relieves.

关键词： AZ31 magnesium alloy Superplasticity Intergranular cavity Filament

Microstructural and Microhardness Variation of Amorphous Fe_(78)Si_9B_(13) Alloy during Bend Stress Relaxation

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Journal of Materials Science & Technology 2007年第2期23卷 253-256页

作者： Xifeng LI Kaifeng ZHANG Changli wang Wenbo HAN guofeng wang School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China Advanced Manufacturing Technology Research Centre Department of Industrial and Systems Engineering The Hong Kong Polytechnic University Hung Hom Hong Kong China

The amorphous Fe78Si9B13 ribbons were bend stress relaxed at various temperature well below the crystallization temperature （Tx） for different time. The effect of pre-annealing on the subsequent bend stress relaxation was examined. The variation of the microstructure and microhardness during bend stress relaxation process was studied using X-ray diffraction （XRD）, atomic force microscopy （AFM） and Vickers microhardness test,respectively. Curvature radius of the amorphous Fe78Si9B13 ribbons decreased with increase bend stress relaxation temperature and time. The microhardness of the stress relaxed specimens increased with time at 300℃ due to the forming of nanocrystals during bend stress relaxation. The pre-annealing reduced the decrease rate of the curvature radius of stress relaxed specimens.

关键词： Bend stress relaxation Amorphous Fe78Si9B13 alloy Microstructure Microhardness