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Effects of the nozzle structure and fluidized gas composition on the gas-particle two-phase jet characteristic in a powder fuel scramjet

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Particuology 2024年第9期92卷 166-179页

作者： Changfei Zhuo Hongming ding Xiaobin Ren Hanyu Deng Xiong chen School of Mechanical and Engineering Key Laboratory of Special Engine TechnologyMinistry of EducationNanjing University of Science and TechnologyNanjing210094China department of Mechanical Engineering National University of Singapore9 Engineering Drive 1Singapore117576 Shanxi North Xing'an Chemical Industry Co. Ltd.Taiyuan030008China

The interaction between nozzle design and fluidization gas composition significantly influences the dynamics within a powder fuel scramjet's combustion *** investigate this relationship,an experimental study utilized high-speed shadow imaging technology to explore the macroscopic aspects of powder fuel *** investigation examined various convergence angles,nozzle throat lengths,and fluidized gas *** findings include:During jet development,powder fuel initially concentrates near the axis,with non-convergence angle nozzles exhibiting longer concentrated distribution periods than convergence angle *** nozzle convergence angles lead to increased penetration distance,frontal velocity,and radial diffusion distance during the initial stages of jet ***,stable jet shapes show larger divergence angles as nozzle convergence angle decreases,with the largest divergence angle observed atα=60°.In the initial 0-7 ms of jet development,the powder fuel jet demonstrates greater penetration distance and frontal velocity under certain ***,penetration distance and frontal velocity increase with throat length from 7 to 20 ms,accompanied by changes in divergence ***,at a throat length(l)of 2 mm,the near-field divergence angle measures 46.50°,and the far-field divergence angle is 22.25°.Conversely,at l=8mm,the near-field divergence angle is 33.49°,and the far-field divergence angle is 23.21°.The fluidization gas composition minimally affects jet penetration distance and frontal velocity during the initial 0-3 ***,due to hydrogen's low density,hydrogen/powder fuel jets exhibit shorter distances and velocities compared to nitrogen/powder fuel *** fluidization also results in larger divergence angles,particularly in the near *** findings underscore the importance of nozzle design and fluidization gas composition in optimizing scramjet performance and efficiency.

关键词： Multiphase flows Gas-particle two-phase jet Nozzle contraction angle Powder fuel scramjet

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An effective catalyst carrier SiO_(2):Enhancing catalytic and combustion properties of CuFe_(2)O_(4)on energetic components

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Defence technology（防务技术） 2024年第2期32卷 383-392页

作者： Li ding Chong Wan Suhang chen Zhao Qin Kangzhen Xu School of Chemical Engineering/Xi'an Key Laboratory of Special Energy Materials Northwest UniversityXi'an710069China Xi’an Modern Chemistry Research Institute Xi'an710065China

To enhance the catalytic activity of copper ferrite(CuFe_(2)O_(4))nanoparticle and promote its application as combustion catalyst,a low-cost silicon dioxide(SiO_(2))carrier was employed to construct a novel CuFe_(2)O_(4)/SiO_(2)binary composites via solvothermal *** phase structure,morphology and catalytic activity of CuFe_(2)O_(4)/SiO_(2)composites were studied firstly,and thermal decomposition,combustion and safety performance of ammonium perchlorate(AP)and 1,3,5-trinitroperhydro-1,3,5-triazine(RDX)with it affecting were then systematically *** results show that CuFe_(2)O_(4)/SiO_(2)composite can remarkably either advance the decomposition peak temperature of AP and RDX,or reduce the apparent activation energy at their main decomposition ***,the flame propagation rate of RDX was promoted by about 2.73 times with SiO_(2)content of 3 wt%,and safety property of energetic component was also improved greatly,in which depressing the electrostatic discharge sensitivity of pure RDX by about 1.89 *** addition,the effective range of SiO_(2)carrier content in the binary catalyst is found to be 3 to 5 wt%.Therefore,SiO_(2)opens a new insight on the design of combustion catalyst carrier and will promote the application of CuFe_(2)O_(4)catalyst in solid propellant.

关键词： Copper ferrite Silicon dioxide Combustion catalyst Thermal decomposition Laser ignition

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A zincophilic molecular brush for a dendrite-free,corrosionresistant,zinc metal anode with a long life cycle

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Nano Research 2024年第1期17卷 390-396页

作者： Penggao Liu Jia Guo Xinyue chen Ting Wang yanping Huang Shasha Gao Tao Wang Dongling Wu Kaiyu Liu State Key Laboratory of Chemistry and Utilization of Carbon based Energy Resources College of ChemistryXinjiang UniversityUrumqi 830017China Hunan Provincial Key Laboratory of Chemical Power Sources College of Chemistry and Chemical EngineeringCentral South UniversityChangsha 410083China Key Laboratory of New Low-carbon Green Chemical technology School of Chemistry and Chemical EngineeringEducation Department of Guangxi Zhuang Autonomous RegionGuangxi UniversityNanning 530004China Key Laboratory of Microelectronics and Energy of Henan Province Department of Physics and Electronic EngineeringXinyang Normal UniversityXinyang 464000China Interdisciplinary Research Center for Sustainable Energy science and Engineering(IRC4SE2) School of Chemical EngineeringZhengzhou UniversityZhengzhou 450001China

Zinc-based aqueous rechargeable batteries have attracted extensive attention due to their low cost,safety,and environmental ***,dendrite growth and hydrogen evolution of Zn anodes limit their large-scale application.A new strategy to produce a polyacrylamide/reduced graphene oxide(PAM@rGO)molecular nanobrush coating and control Zn electrolyte interface engineering is proposed for use in highly reversible Zn plating/*** evolution is inhibited,and Zn deposition is consolidated using the rich zincophilic functional groups of the branched polyacrylamide chain and the high conductivity of *** to the synergistic effects of corrosion resistance and dendrite-free growth,PAM@rGO/Zn provides prolonged and reversible Zn plating/*** functional theory(DFT)calculations expand on homogenized *** PAM@rGO/Zn||activated carbon(AC)capacitor exhibits long cyclic stability,fast ion transfer,and minimal interfacial *** study provides experimental and theoretical bases for the structural design of Zn anode.

关键词： zincophilic nanobrush polyacrylamide/reduced graphene oxide(PAM@rGO)/Zn surface modification Zn based energy storage

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Augmented reality registration algorithm based on nature feature recognition

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science china(Information sciences) 2010年第8期53卷 1555-1565页

作者： chen Jing 1 , WANG yongTian 1,2 , GUO JunWei 1 , LIU Wei 1 , LIN JingDun 1 , XUE Kang 1 , LIU Yue 1 & ding GangYi 31 School of Optoelectronics, beijing Institute of technology, beijing 100081, china 2 School of Computer science and technology, beijing Institute of technology, beijing 100081, china 3 School of Software, beijing Institute of technology, beijing 100081, china 1. School of Optoelectronics Beijing Institute of Technology Beijing 100081 China2. School of Computer Science and Technology Beijing Institute of Technology Beijing 100081 China3. School of Software Beijing Institute of Technology Beijing 100081 China

This paper presents an improved key frame based augmented reality registration algorithm for real-time motion tracking in outdoor environment. In such applications, wide-baseline feature matching is a critical problem. In this paper, we apply randomized tree method to match key points extracted from the input image to those key frames as a classification problem. Extended Kalman filter is also utilized for jitter correction. A video see-through mobile augmented reality system is built for the on-site digital reconstruction of Yuanmingyuan Garden. Experimental results demonstrate that this algorithm is real-time, robust and effective for outdoor tracking.

关键词： outdoor augmented reality camera tracking randomized tree

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High-Performance All-Printed Flexible Micro-Supercapacitors with Hierarchical Encapsulation

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Energy & Environmental Materials 2024年第4期7卷 262-268页

作者： Yuhang Yuan Wei Yuan Yaopeng Wu Xuyang Wu Xiaoqing Zhang Simin Jiang Bote Zhao Yu chen chenghao Yang Liangxin ding Zhenghua Tang Yingxi Xie yong Tang School of Mechanical & Automotive Engineering South China University of Technology School of Environment and Energy South China University of Technology School of Chemistry and Chemical Engineering South China University of Technology

Printed micro-supercapacitors (MSCs) have shown broad prospect in flexible and wearable *** of previous studies focused on printing the electrochemically active materials paying less attention to other key components like current collectors and *** study presents an allprinting strategy to fabricate in-plane flexible and substrate-free MSCs with hierarchical encapsulation.

关键词： all-printing flexible hierarchical encapsulation micro-supercapacitors substrate-free

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Dynamic tracking of exsolved PdPt alloy/perovskite catalyst for efficient lean methane oxidation

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Chinese Chemical Letters 2024年第4期35卷 170-175页

作者： Yanling Yang Zhenfa ding Huimin Wang Jianhui Li yanping Zheng Hongquan Guo Li Zhang Bing Yang Qingqing Gu Haifeng Xiong Yifei Sun College of Energy Xiamen UniversityXiamen 361005China School of Environment and Civil Engineering Dongguan University of TechnologyDongguan 523808China department of Chemistry College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China CAS Key Laboratory of science and technology on Applied Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China Innovation Laboratory for sciences and Technologies of Energy Materials of Fujian Province(IKKEM) Xiamen 361102China

Supported Pd based catalysts are considered as the efficient candidates for low-carbon alkane oxidation for their outstanding capability to break C-H bond. Whereas, the irreversible deactivation of Pd based catalysts was still frequently observed. Herein, we reinforced the extruded Pd nanoparticles with quantitive Pt to assemble the evenly distributed Pd Pt nanoalloy onto ferrite perovskite(Pd Pt-LCF) matrix with strengthened robustness of metal/oxide support interface. We further co-achieved the enhanced performance, anti-overoxidation as well as resistance of vapor-poisoning in durability measurement. The operando X-ray photoelectron spectroscopy(O-XPS) combined with various morphology characterizations confirms that the accumulation of surface deep-oxidation species of Pd^(4+) is the culprit for fast activity loss in exsolved Pd system, especially at high temperature of 400 ℃. Conversely, it could be completely suppressed by in-situ alloying Pd with equal amount of Pt, which helps maintain the metastable Pd^(2+)/Pd shell and metallic solid-solution core structure. The density function theory(DFT) calculations further buttress that the dissociation of C–H was facilitated on alloy/perovskite interface which is, on the contrary, resistant toward O–H bond cleavage, as compared to Pd/perovskite. Our work suggests that the modification of exsolved metal/oxide catalytic interface could further enrich the toolkit of heterogeneous catalyst design.

关键词： Exsolution PdPt alloy Operando characterization Methane conversion Deep-oxidation

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Multidimensional regulation of Ti-Zr-Cr-Mn hydrogen storage alloys via Y partial substitution

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Nano Research 2024年第5期17卷 4211-4220页

作者： Haixiang Xiu Wanqiang Liu Dongming Yin Nan ding Wenfeng Qiao Shaolei Zhao Long Liang Cong Liu Shaohua Wang Qingshuang Wang Bingbing chen Limin Wang yong cheng School of Materials science and Engineering Changchun University of Science and TechnologyChangchun 130022China State Key Laboratory of Rare Earth Resources Utilization Changchun Institute of Applied ChemistryChinese Academy of Sciences(CAS)Changchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China department of Energy science and Engineering Nanjing Tech UniversityNanjing 211816China National Engineering Research Center of Nonferrous Metals Materials and Products for New Energy GRINM Group Co.Ltd.Beijing 100088China GRIMAT Engineering Institute Co. Ltd.Beijing 101407China College of Life science and technology Changchun University of Science and TechnologyChangchun 130022China

High density and safe storage of hydrogen are the preconditions for the large-scale application of hydrogen ***,the hydrogen storage properties of Ti_(0.6)Zr_(0.4)Cr_(0.6)Mn_(1.4) alloys are systematically studied by introducing Y element instead of Ti element through vacuum arc *** the partial substitution of Y,a second phase of rare earth oxide is added in addition to the main suction hydrogen phase,C14 Laves *** to the unique properties of rare earth elements,the partial substitution of Y can not only improve the activation properties and plateau pressure of the alloys,but also increase the effective hydrogen storage capacity of the *** comprehensive properties of hydrogen storage alloys are improved by multidimensional regulation of rare earth *** them,Ti_(0.552)Y_(0.048)Zr_(0.4)Cr_(0.6)Mn_(1.4) has the best comprehensive *** alloy can absorb hydrogen without activation at room temperature and 5 MPa,with a maximum hydrogen storage capacity of 1.98 wt.%.At the same time,it reduces the stability of the hydride and the enthalpy change value,making it easier to release *** theoretical analysis and first-principle simulation,the results show that the substitution of Y element reduces the migration energy barrier of hydrogen and the structural stability of the system,which is conducive to hydrogen *** alloy has superior durability compared to the original alloy,and the capacity retention rate was 96.79%after 100 hydrogen absorption/desorption cycles.

关键词： AB_(2)-type hydrogen storage alloy rare earth element first-principles simulation multidimensional regulation

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Winter Wheat Yield Estimation Based on Sparrow Search Algorithm Combined with Random Forest:A Case Study in Henan Province,china

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Chinese Geographical science 2024年第2期34卷 342-356页

作者： SHI Xiaoliang chen Jiajun ding Hao YANG Yuanqi ZHANG Yan College of Geomatics Xi’an University of Science and TechnologyXi’an 710054China

Precise and timely prediction of crop yields is crucial for food security and the development of agricultural ***,crop yield is influenced by multiple factors within complex growth *** research has paid relatively little attention to the interference of environmental factors and drought on the growth of winter ***,there is an urgent need for more effective methods to explore the inherent relationship between these factors and crop yield,making precise yield prediction increasingly *** study was based on four type of indicators including meteorological,crop growth status,environmental,and drought index,from October 2003 to June 2019 in Henan Province as the basic data for predicting winter wheat *** the sparrow search al-gorithm combined with random forest(SSA-RF)under different input indicators,accuracy of winter wheat yield estimation was *** estimation accuracy of SSA-RF was compared with partial least squares regression(PLSR),extreme gradient boosting(XG-Boost),and random forest(RF)***,the determined optimal yield estimation method was used to predict winter wheat yield in three typical *** are the findings:1)the SSA-RF demonstrates superior performance in estimating winter wheat yield compared to other *** best yield estimation method is achieved by four types indicators’composition with SSA-RF)(R^(2)=0.805,RRMSE=9.9%.2)Crops growth status and environmental indicators play significant roles in wheat yield estimation,accounting for 46%and 22%of the yield importance among all indicators,respectively.3)Selecting indicators from October to April of the follow-ing year yielded the highest accuracy in winter wheat yield estimation,with an R^(2)of 0.826 and an RMSE of 9.0%.Yield estimates can be completed two months before the winter wheat harvest in June.4)The predicted performance will be slightly affected by severe *** with severe drought year(201

关键词： winter wheat yield estimation sparrow search algorithm combined with random forest(SSA-RF) machine learning multi-source indicator optimal lead time Henan Province,china

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Unveiling optical anisotropy in disrupted symmetry WSe_(2)/SiP heterostructures

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Nano Research 2024年第9期17卷 8585-8591页

作者： Biqi Hu Xing Xie Xinyu Ouyang Junying chen Shaofei Li Jun He Zongwen Liu Jian-Tao Wang yanping Liu Institute of Quantum Physics School of PhysicsCentral South University932 South Lushan RoadChangsha 410083China State Key Laboratory of Precision Manufacturing for Extreme Service Performance Central South University932 South Lushan RoadChangsha 410083China School of Chemical and Biomolecular Engineering The University of SydneyNSW 2006Australia The university of Sydney Nano Institute The University of SydneyNSW 2006Australia beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical sciences University of Chinese Academy of SciencesBeijing 100049China Songshan Lake Materials Laboratory Dongguan 523808China Shenzhen Research Institute of Central South university Shenzhen 518000China

Two-dimensional(2D)transition metal dichalcogenides(TMDs)have garnered considerable attention for their promising applications in sensors and optoelectronic devices,owing to their exceptional optical,electronic,and optoelectronic ***,the inherent high symmetry of TMD lattices imposes limitations on their functional ***,we present a strategy to disrupt the C_(3)rotational symmetry of monolayer WSe_(2)by fabricating a heterostructure incorporating WSe_(2)and SiP *** comprehensive experimental investigations and first-principle calculations,we elucidate that in the WSe_(2)/SiP heterostructure,excitons-both neutral and charged-emanating from WSe_(2)exhibit pronounced anisotropy,which remains robust against temperature ***,we observe an anisotropic ratio reaching up to 1.5,indicating a substantial degree of ***,we demonstrate the tunability of exciton anisotropy through the application of a magnetic field,resulting in a significant reduction in the anisotropic ratio with increasing field strength,from 1.57 to ***,the change in heterojunction anisotropy ratio reaches 24.8%as the magnetic field *** findings elucidate that the perturbation of the C_(3)rotational symmetry of the WSe_(2)monolayer arises from a non-uniform charge density distribution within the layer,exhibiting mirror *** results underscore the potential of heterostructure engineering in tailoring the properties of isotropic materials and provide a promising avenue for advancing the application of anisotropic devices across various fields.

关键词： symmetry breaking heterostructure engineering anisotropy optical spectroscopy

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Suppressing the Undesirable Energy Loss in Solution-Processed Hyperfluorescent OLEDs Employing BODIPY-Based Hybridized Local and Charge-Transfer Emitter

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Energy & Environmental Materials 2024年第2期7卷 372-380页

作者： Xuewei Nie Zafar Mahmood Denghui Liu Mengke Li Dehua Hu Wencheng chen Longjiang Xing Shijian Su yanping Huo Shaomin Ji School of Chemical Engineering and Light Industry Guangdong University of TechnologyGuangzhou 510006China State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices South China University of TechnologyGuangzhou 510640China

Hyperfluorescent organic light-emitting diodes(HF-OLEDs)approach has made it possible to achieve excellent device performance and color purity with low roll-off using noble-metal-free pure organic *** significant progress,the performance of HF-OLEDs is still unsatisfactory due to the existence of a competitive dexter energy transfer(DET)*** this contribution,two boron dipyrromethene(BODIPY)-based donor-acceptor emitters(BDP-C-Cz and BDP-N-Cz)with hybridized local and charge transfer characteristics(HLCT)are introduced in the HF-OLED to suppress the exciton loss by dexter mechanism,and a breakthrough performance with low-efficiency roll-off(0.3%)even at high brightness(1000 cd m^(-2))is *** is demonstrated that the energy loss via the DET channel can be suppressed in HF-OLEDs utilizing the HLCT emitter,as the excitons from the dark triplet state of such emitters are funneled to its emissive singlet state following the hot-exciton *** developed HF-OLED device has realized a good maximum external quantum efficiency(EQE)of 19.25%at brightness of 1000 cd m^(-2)and maximum luminance over 60000 cd m^(-2),with an emission peak at 602 nm and Commission International de L'Eclairage(CIE)coordinates(0.57,0.41),which is among the best-achieved results in solution-processed *** work presents a viable methodology to suppress energy loss and achieve high performance in the HF-OLEDs.

关键词： BODIPY hyperfluorescence organic light-emitting diodes solution-process

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