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Effect of expansion waves on cowl shock wave and boundary layer interaction in hypersonic inlet

Propulsion and Power Research 2024年第1期13卷 80-97页

作者： Guangwei Wu Ziao Wang Teng Shi Zhibin Zhang Weiyu Jiang Fuxu Quan Juntao chang Harbin Institute of Technology Harbin 150001China Xi’an Aerospace Propulsion Institute Xi’an 710100China Beijing Power Machinery Institute Beijing 100074China

The interaction of cowl shock wave and boundary layer has a crucial effect on the stability,operability and performance of hypersonic *** studies on inhibiting the sep-aration and managing the strength of the interaction of the shock wave and boundary layer with expansion corner have been ***,the expansion waves near the circular arc shoulder to effectively control the interaction and cowl shock arrangement is little ***,the interaction of the cowl shock wave and boundary layer under thefluence of the expansion waves is studied by inviscid and viscous numerical *** results reveal that the expansion waves have an important impact on the interaction between the cowl shock wave and boundary layer and the strength of shock wave,and that there are four types of inter-action processes with the change of the relative impingement positions of cowl shock *** expansion waves have a different influence on the shock wave and boundary layer inter-action at different incident *** the incident point of the cowl shock wave goes far downstream from the end of the circular arc shoulder,the influence of expansion waves is weakened,and the magnitude of separation zone ***,when the expansion waves are applied to the interaction of the cowl shock wave and boundary layer on the circular arc shoulder,the separation can be effectively *** particular,while the expansion waves interact with the shock wave and boundary layer in the back half of the circular arc shoulder,the separation is best *** with the upstream and downstream inci-dent points,the scale of separation area in the optimal control region is reduced by 65.3%at ***,the total pressure recovery coefﬁcientﬁrst increases and then decreases when the cowl moves from upstream to downstream,and the total pressure recovery coefﬁcient reaches the maximum value of 68.36%at the incident position of cowl shock wave d Z 8.09d0.

关键词： Boundary layer Expansion waves Cowl shock wave Separation Hypersonic inlet Circular arc shoulder Inviscid and viscous numerical simulations

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Path analysis of desirable traits and evaluation of reproductive performance of Crassostrea sikamea in different ages

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Aquaculture and Fisheries 2024年第2期9卷 164-171页

作者： Guangqiu chang Sheng Liu Hongqiang Xu Minhai Liu Zhihua Lin Qinggang Xue National demonstration Center for Experimental Fisheries Science Education Shanghai Ocean UniversityShanghai201306China Ninghai Institute of Mariculture Breeding and Seed Industry Zhejiang Wanli UniversityNinghaiZhejiang Province315604China Key Laboratory of Aquatic Germplasm Resources of Zhejiang Zhejiang Wanli UniversityNingbo315100China

Kumamoto oysters(Crassostrea sikamea)are important marine aquaculture shellfish because of their taste and round shell *** to its small size,selective breeding is required to improve its market size,but there are no reports on traits suitable for direction selection and reproductive productivity of Kumamoto oysters of different *** this study,path analysis and one-way ANOVA were used to explore the influential indices of oyster body weight and *** results showed that shell height was the main factor affecting the body weight of Kumamoto oysters at one-year-old and two-year-old,followed by shell *** weight was the main factor influencing fecundity,and shell height showed a significant correlation with ***,shell height should be considered the first parameter for selection when selecting Kumamoto oysters for body weight as the direct selection *** one-year-old and two-year-old Kumamoto oysters were selected as parents from Xiangshan Bay,hatching parameters and growth parameters of F1 generation larvae were *** fecundity and egg diameters were 1.72×10^(6)and 46.60±3.62μm,respectively,which were significantly greater than one-aged oysters(5.86×10^(5),40.26±3.52μm).The hatching parameters(fertilized egg size,fertilization rate,and hatching rate)and larval growth performance(d-stage veliger and veliger)were similar and did not differ significantly(P>0.05),and after metamorphosis,there was also no significant difference in shell height size at 40 days of age(P>0.05).Therefore,there was no significant effect of age on reproduction,larval development,and the early growth of Kumamoto *** results could provide a basis for parental sources and proper traits for Kumamoto oyster selection,which is beneficial to developing and utilizing this excellent germplasm resource.

关键词： Crassostrea sikamea Path analysis Reproductive performance Growth traits

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Unsupervised Oral Endoscope Image Stitching Algorithm

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Journal of Shanghai Jiaotong university(Science) 2024年第1期29卷 81-90页

作者：黄荣常青张扬 School of Information Science and Engineering East China University of Science and TechnologyShanghai 200237China

Oral endoscope image stitching algorithm is studied to obtain wide-field oral images through regis-tration and stitching,which is of great significance for auxiliary *** with natural images,oral images have lower textures and fewer ***,traditional feature-based image stitching methods rely heavily on feature extraction quality,often showing an unsatisfactory performance when stitching images with few ***,due to the hand-held shooting,there are large depth and perspective disparities between the captured images,which also pose a challenge to image *** overcome the above problems,we propose an unsupervised oral endoscope image stitching algorithm based on the extraction of overlapping regions and the loss of deep *** the registration stage,we extract the overlapping region of the input images by sketching polygon intersection for feature points screening and estimate homography from coarse to fine on a three-layer feature pyramid ***,we calculate loss using deep features instead of pixel values to emphasize the importance of depth disparities in homography ***,we reconstruct the stitched images from feature to pixel,which can eliminate artifacts caused by large *** method is compared with both feature-based and previous deep-based methods on the UdIS-d dataset and our oral endoscopy image *** experimental results show that our algorithm can achieve higher homography estimation accuracy,and better visual quality,and can be effectively applied to oral endoscope image stitching.

关键词： oral endoscope image overlapping region homography estimation image stitching

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A review on ultra-small undoped MoS_(2) as advanced catalysts for renewable fuel production

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Carbon Energy 2024年第2期6卷 92-112页

作者： Guoping Liu Lingling ding Yuxuan Meng Ahmad Ali Guifu Zuo Xianguang Meng Kun chang Oi Lun Li Jinhua Ye Hebei Provincial Laboratory of Inorganic Nonmetallic Materials College of Materials Science and EngineeringNorth China University of Science and TechnologyTangshanChina College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjingChina School of Materials Science and Engineering Pusan National UniversityBusanKorea International Center for Materials Nanoarchitectonics(WPIMANA) National Institute for Materials Science(NIMS)1-1 NamikiTsukubaIbarakiJapan

Molybdenum disulfide(MoS_(2))has garnered significant attention in the field of catalysis due to the high density of active sites in its unique two-dimensional(2d)structure,which could be developed into numerous high-performance *** synthesis of ultra-small MoS2 particles(desired in various experimental *** ultra-small structure could often lead to a distinct S-Mo coordination state and nonstoichiometric composition in MoSx,minimizing in-plane active sites of the 2d structure and making it probable to regulate the atomic and electronic structure of its intrinsic active sites on a large extent,especially in MoSx *** article summarizes the recent progress of catalysis over ultra-small undoped MoS_(2) particles for renewable fuel *** a systematic review of their synthesis,structural,and spectral characteristics,as well as the relationship between their catalytic performance and inherent defects,we aim to provide insights into catalysis over this matrix that may potentially enable advancement in the development of high-performance MoS_(2)-based catalysts for sustainable energy generation in the future.

关键词： applications catalytic MoS_(2) structure synthesis

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3d-Printed Monolith Metallic Ni-Mo Electrodes for Ultrahigh Current Hydrogen Evolution

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Energy & Environmental Materials 2024年第5期7卷 228-237页

作者： Yanran Xun Hongmei Jin Yuemeng Li Shixiang Zhou Kaixi Zhang Xi Xu Win Jonhson Shuai chang Teck Leong Tan Jun ding department of Materials Science and Engineering National University of Singapore Institute of High Performance Computing (IHPC) Agency for Science Technology and Research (ASTAR) Key Laboratory of Flexible Electronics of Zhejiang Province Ningbo Institute of Northwestern Polytechnical University State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology

In this work, we reported a series of monolithic 3d-printed Ni–Mo alloy electrodes for highly efficient water splitting at high current density(1500 mA cm-2) with excellent stability, which provides a solution to scale up Ni–Mo catalysts for HER to industry use. All possible Ni–Mo metal/alloy phases were achieved by tuning the atomic composition and heat treatment procedure, and they were investigated through both experiment and simulation, and the optimal NiMo phase shows the best performance.

关键词： 3d-printed electrode Ni–Mo catalyst phase tuning ultra-high current density HER

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Subspace Clustering via Block-diagonal decomposition

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Chinese Journal of Electronics 2024年

作者： Zhiqiang FU Yao ZHAO dongxia chang Yiming WANG Institute of Information Science Beijing Jiaotong University Beijing Key Laboratory of Advanced Information Science and Network Technology China Construction Bank

The subspace clustering has been addressed by learning the block-diagonal self-expressive matrix. This block-diagonal structure heavily affects the accuracy of clustering but is rather challenging to obtain. A novel and effective subspace clustering model, i.e., subspace clustering via block-diagonal decomposition(SCBd), that can simultaneously capture the block-diagonal structure and gain the clustering result is proposed. In our model, a strict blockdiagonal decomposition is introduced to directly pursue the k block-diagonal structure corresponding to k clusters. In this novel decomposition, the self-expressive matrix is decomposed into the block indicator matrix to demonstrate the cluster each sample belongs to. Based on the strict block-diagonal decomposition, the block-diagonal shift is proposed to capture the local intra-cluster structure, which shifts the samples in the same cluster to get smaller distances and results in more discriminative features for clustering. Extensive experimental results on synthetic and real databases demonstrate the superiority of SCBd over other state-of-the-art methods.

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Self-powered wireless environmental monitoring system for in-service bridges by galloping piezoelectric-triboelectric hybridized energy harvester

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Science China(Technological Sciences) 2024年第5期67卷 1498-1509页

作者： HUANG KangXu WANG XiaoFei WANG Li ZHOU YuHui LIU FuHai chang ShiYuan ZHU JunTao ZHOU YuXuan ZHANG He LUO JiKui College of Civil Engineering and Architecture Zhejiang UniversityHangzhou310058China Anhui Transport Consulting&design Institute Co. Ltd.Hefei230088China College of Electronics&Information Hangzhou Dianzi UniversityHangzhou310018China Center for Balance Architecture Zhejiang UniversityHangzhou310058China College of Information Science&Electronic Engineering Zhejiang UniversityHangzhou310027China

The energy harvesting technology for the ubiquitous natural wind enables a desirable solution to the issue of distributed sensors in the bridge environmental sensing Internet of Things(Io T)system being restricted to conventional energy *** this work,a self-powered system based on a compact galloping piezoelectric-triboelectric energy harvester(GPTEH)is developed to achieve efficient wind energy *** GPTEH is constructed on the prototype of a cantilever structure with piezoelectric macro-fiber composite(MFC)sheets and a rectangular bluff body with triboelectric nanogenerators(TENGs).Through a special swing-type structural design with iron blocks inside the bluff body,the GPTEH exhibits preferable aerodynamic behavior and excellent energy conversion efficiency,compared to conventional cantilever kind of piezoelectric wind energy harvester(PWEH).The GPTEH also demonstrates the capability of high output power density(PEH of 23.65 W m^(-2)and TENG of 1.59 W m^(-2)),superior response wind speed(about 0.5 m s^(-1)),and excellent long-term stability(over 14000 cyclic tests).Furthermore,a power management system is developed to efficiently utilize the output energy from GPTEH to power the sensors and wirelessly transmit environmental data to the *** proposed GPTEH-powered system exhibits a great potential for the bridge environmental monitoring and Io T technologies.

关键词： self-powered hybrid nanogenerator triboelectric nanogenerator macro-fiber composite wireless environmental monitoring system

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EventLFM:event camera integrated Fourier light field microscopy for ultrafast 3d imaging

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Light(Science & Applications) 2024年第7期13卷 1401-1415页

作者： Ruipeng Guo Qianwan Yang Andrew S.chang Guorong Hu Joseph Greene Christopher V.Gabel Sixian You Lei Tian department of Electrical and Computer Engineering Boston UniversityBostonMA 02215USA department of Physiology and Biophysics Boston UniversityBostonMA 02215USA. Neurophotonics Center Boston UniversityBostonMA 02215USA. Research Laboratory of Electronics(RLE)in the department of Electrical Science and Engineering Massachusetts Institute of TechnologyCambridgeMA 02139USA. department of Biomedical Engineering Boston UniversityBostonMA 02215USA

Ultrafast 3d imaging is indispensable for visualizing complex and dynamic biological *** scanning-based techniques necessitate an inherent trade-off between acquisition speed and space-bandwidth product(SBP).Emerging single-shot 3d wide-field techniques offer a promising alternative but are bottlenecked by the synchronous readout constraints of conventional CMOS systems,thus restricting data throughput to maintain high SBP at limited frame *** address this,we introduce EventLFM,a straightforward and cost-effective system that overcomes these challenges by integrating an event camera with Fourier light field microscopy(LFM),a state-of-theart single-shot 3d wide-field imaging *** event camera operates on a novel asynchronous readout architecture,thereby bypassing the frame rate limitations inherent to conventional CMOS *** further develop a simple and robust event-driven LFM reconstruction algorithm that can reliably reconstruct 3d dynamics from the unique spatiotemporal measurements captured by *** results demonstrate that EventLFM can robustly reconstruct fast-moving and rapidly blinking 3d fluorescent samples at kHz frame ***,we highlight EventLFM’s capability for imaging of blinking neuronal signals in scattering mouse brain tissues and 3d tracking of GFP-labeled neurons in freely moving *** believe that the combined ultrafast speed and large 3d SBP offered by EventLFM may open up new possibilities across many biomedical applications.

关键词： field linking overcome

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Exciton Bose–Einstein Condensation in Transition Metal dichalcogenide Monolayer under In-Plane Magnetic Fields

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Chinese Physics Letters 2024年第8期41卷 69-76页

作者： dengfeng Wang Yingda Chen Zhi-Chuan Niu Wen-Kai Lou Kai chang SKLSM Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China College of Materials Science and Opto-electronic Technology Center of Materials Science and Optoelectronics EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China School of Physics Zhejiang UniversityHangzhou 310027China

Based on the Gross–Pitaevskii equation,we theoretically investigate exciton Bose–Einstein condensation(BEC)in transition metal dichalcogenide monolayers(TMdC-MLs)under in-plane magnetic *** observe that the in-plane magnetic fields exert a strong influence on the exciton BEC wave functions in TMdC-MLs because of the mixing of the bright and dark exciton states via Zeeman *** leads to the brightening of the dark exciton BEC *** competition between the dipole–dipole interactions caused by the long-range Coulomb interaction and the Zeeman effect induced by the in-plane magnetic fields can effectively regulate dark exciton BEC *** findings emphasize the utility of TMd-MLs as platforms for investigating collective phenomenon involving excited states.

关键词： effect Einstein dipole

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Metal-Free Electrochemical Trifluoromethylation of Imidazole-Fused Heterocycles with Trifluoromethyl Thianthrenium Triflate

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Chinese Journal of Chemistry 2024年第15期42卷 1679-1685页

作者： chang Ge Lipeng Qiao Yuyang Zhang Kai Sun jangzhen An Mei Peng Xiaolan Chen Lingbo Qu Bing Yu College of Chemistry Zhengzhou UniversityZhengzhouHenan 450001China National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass Nanjing Forestry UniversityNanjingJiangsu210037China School of Pharmacy Hengyang Medical SchoolUniversity of South ChinaHengyangHunan 421001China

A novel and eco-friendly electrochemical activation of trifluoromethyl thianthrenium triflate(TT-CF_(3)^(+)OTf^(-))for trifluoromethylation of imidazole-fused heteroaromatic compounds was *** method involves the direct electrolysis of TT-CF_(3)^(+)OTf^(-)without the requirement of external oxidants or catalysts,aligning with the principles of green chemistry.A wide range of imidazole-fused heteroaromatic compounds including imidazo[1,2-a]pyridines and benzo[d]imidazo[2,1-b]thiazoles have been successfully trifluoromethylated using this technique,exhibiting excellent compatibility with various functional groups and a broad substrate ***,the method's applicability for one-pot sequential reactions enables the reduction of waste and resource consumption by eliminating the need for intermediate purification steps.

关键词： Trifluoromethylation Electrochemical Metal-free Imidazole-fused heterocycles Thianthrenium

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