检索结果-南通市图书馆

Numerical Investigation on the Effects of Re-Organized Shock Waves on the Flow Separation for a Highly-Loaded Transonic Compressor Cascade

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Thermal Science 2012年第1期21卷 13-20页

作者： Wang Yan gang Guo rui Zhao Longbo ren Siyuan School of Power ＆ Energy Northwestern Polytechincal University

This paper presents a detailed numerical investigation of the influence of re-organized shock waves on the flow separation for a highly-loaded transonic compressor cascade. The boundary layer suction (BLS) was used to control the location and strength of shock waves, with the aspirated slot locating at 49% chord, where is just downstream of the impingement point of shock wave at the leading edge. The numerical simulation is based on NUMECA, a commercial software, where the cell-centered control volume approach with third-order spatial accuracy is used to solve the 3-D Reynolds-averaged Navier-Stokes equations under the Cartesian coordinate system. Several conclusions can be made through the observation of the numerical results. (1) Multiple shock waves in cascade passage leaded the velocity deficits of boundary layer on suction surface downstream of shock wave, resulting in seriously separated flow on the suction side of blade, especially when the front shock wave is much stronger than the rest of the shocks. (2) BLS with small mass flow rate can not effectively improve the boundary layer. When the impingement point of oblique shock wave coming from cascade leading edge is bled to downstream of the passage shock wave by BLS, the boundary layer flow is greatly improved. However, if the BLS mass flow rate exceeds a critical value (1.2%), the boundary layer downstream of shock wave would separate from suction surface. (3) At the blade mid-span, the aerodynamic performance of compressor blade is improved as BLS mass flow rate increases. The optimum BLS is about 1.2%. Compared with the baseline case, the BLS with flow rate of 1.2% increases the total pressure recovery coefficient by 12%, and decreases diffusion factor by 18% and deviation angle to 7 ° while keeping the pressure rise constant. (4) The three dimensional flow structure of the compressor cascade ranged from 25% span to 75% span was improved greatly with the 1.2% BLS flow rate. However it could not control th

关键词： suction flow shock wave boundary layer interaction effects

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于CRNN改进的中文街景文本识别技术

成都信息工程大学学报 2025年第1期40卷 1-6页

作者：任锐王晓娅文成玉成都信息工程大学通信工程学院四川成都610225

现实场景中存在图像扭曲、背景复杂、弯曲倾斜等不规则文字形状,提取其中的文字信息可提高图像的语义信息和帮助分析上下文,从而更好地理解场景图像。针对场景文本的复杂问题,提出基于CRNN(卷积循环神经网络)改进的端到端场景文本识别... 详细信息

现实场景中存在图像扭曲、背景复杂、弯曲倾斜等不规则文字形状,提取其中的文字信息可提高图像的语义信息和帮助分析上下文,从而更好地理解场景图像。针对场景文本的复杂问题,提出基于CRNN(卷积循环神经网络)改进的端到端场景文本识别技术。在卷积网络层提取特征,基于GoogLeNet改进的inception结构,加人多分支卷积层对多尺度特征的融合,其次融入注意力机制,在通道维度和空间维度加强特征联系,使局部特征拥有全局性。在循环网络层采用Bi-LSTM(双向长短期记忆网络)加强字符之间的上下文联系进行序列预测,最后将预测序列传人CTC(时序分类层)进行转录后序列输出。在ITT5K数据集和百度中文街景数据集上的实验结果表明,该方法分别获得了95.3%和91.1%的准确率,证明其可靠性。

关键词：文本识别卷积神经网络注意力机制双向长短期记忆

Prostate cancer research in China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2013年第3期15卷 350-353页

作者： Shan-Cheng ren rui Chen Ying-Hao Sun Department of Urology Shanghai Changhai Hospital Second Military Medical University Shanghai 200433 China

Prostate cancer （PCa） research in China has been on a rocketing trend in recent years. The first genome-wide association study （GWAS） in China identified two new PCa risk associated single nucleotide polymorphisms （SNPs）. Next generation sequencing is beginning to be used, yielding novel findings： gene fusions, long non-coding RNAs and other variations. Mechanisms of PCa progression have been illustrated while various diagnosis biomarkers have been investigated extensively. Personalized therapy based on genetic factors, nano-medicine and traditional Chinese medicine has been the focus of experimental therapeutic research for PCa. This review intends to shed light upon the recent progress in PCa research in China and points out the possible breakthroughs in the future.

关键词： prostate cancer (PCa) genome-wide association study (GWAS) single nucleotide polymorphisms (SNPs) China

Lewis Acid Catalyzed Synthesis of Vinylene Linked Two Dimensional Covalent Organic Frameworks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2022年第15期40卷 1807-1812页

作者： Bai Bin Xiao-rui ren Dong Wang Li-Jun Wan CAS Key Laboratory of Molecular Nanostructure and Nanotechnology CAS Research/Education Center for Excellence in Molecular SciencesBeijing National Laboratory for Molecular Science(BNLMS)Institute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Comprehensive Summary Vinylene linked covalent organic frameworks(cOFs)have drawn extensive attention due to their desirable stability,carbon conjugation and opto-electronic *** catalyst is a key factor in the synthesis of vinylene linked COFs,and proton acids and bases are widely reported as catalysts so ***,we report the synthesis of vinylene linked cOFs using Lewis acid ZnCl2 as catalyst for the first *** COFs with hexagonal pores of different sizes are synthesized by the reaction of 2,4,6-trimethyl triazine and a series of aromaticaldehydes.

关键词： Covalent organic frameworks Vinylene linkage Lewis acids Zinc chloride Aldol reaction

Convenient Synthesis of Thioester-Substituted Oxindoles by Palladium-Catalyzed Thiocarbonylative Cyclization with Sulfonyl Chlorides as the Sulfur Source

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2023年第2期41卷 188-192页

作者： ren-rui Xu Xiuyu Fang Xinxin Qi Xiao-Feng Wu Department of Chemistry Key Laboratory of Surface&Interface Science of Polymer Materials of Zhejiang ProvinceZhejiang Sci-Tech UniversityHangzhouZhejiang 310018China Dalian National Laboratory for Clean Energy Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalianLiaoning 116023China Leibniz-Institut für Katalys e e.V Albert-Einstein-Straβe 29aRostock 18059Germany

A general and straightforward strategy for the synthesis of thioester-substituted oxindoles via a palladium-catalyzed thiocarbonyla-tive cyclization process has been *** sulfonyl chlorides as promising sulfur source,a wide range of thioester-substituted oxindoles were obtained in moderate to high *** aryl and alkyl sulfonyl chlorides were well tolerated,and Mo(CO)6 played a dual role as both a CO source and a reductant in this approach.

关键词： Alkene Carbonylation Oxindoles Palladium Thiocarbonylation Sulfonyl Chlorides Synthetic methods

Palladium-catalyzed cascade Heck-type thiocarbonylation for the synthesis of functionalized thioesters

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Organic Chemistry Frontiers 2022年第5期9卷 1417-1421页

作者： ren-rui Xu Wei Wang Xinxin Qi Xiao-Feng Wu Department of Chemistry Zhejiang Sci-Tech UniversityHangzhouZhejiang 310018People’s Republic of China Dalian National Laboratory for Clean Energy Dalian Institute of Chemical PhysicsChinese Academy of Sciences116023 DalianLiaoningChina Leibniz-Institut fur Katalyse e.V. Albert-Einstein-Straße 29aRostock 18059Germany

A palladium-catalyzed cascade Heck-type cyclization and carbonylation reaction has been developed for the synthesis of functionalized *** arylsulfonyl chlorides as odorless and readily available sulfur sources,a variety of thioesters were obtained in moderate to good yields with good functional group *** this system,Mo(CO)_(6) acts as both a convenient CO surrogate and a suitable reductant.

关键词： esters catalyzed synthesis

Surface nanostructures in commercial pure Ti induced by high energy shot peening

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2004年第Z1期14卷 215-218页

作者： CHEN Chun-huan ren rui-ming ZHAO Xiu-juan ZHANG Yu-jun School of Materials Science and Engineering Dalian Jiaotong University Dalian 116028 China School of Materials Science and Engineering Dalian Jiaotong University Dalian 116028 China School of Materials Science and Engineering Dalian Jiaotong University Dalian 116028 China School of Materials Science and Engineering Dalian Jiaotong University Dalian 116028 China

The high-energy shot peening (HESP) technique was used to obtain the surface nanocrystalline microstructure for a hcp metal titanium. XRD, SEM and TEM were applied to characterize the microstructure of the surface layer. Large amount of the deformation twins in the surface layer were observed by SEM in the specimens after HESP treatment in a shot-time, and the number of deformation twins both in a single plane and in intersecting planes increases with HESP time, until the twin character disappears completely in the top surface layer, which means that the severe plastic deformation(SPD) occurs on the surface. The XRD analysis results show that after HESP treatmen for 30 - 60 min the surface grain size decreases to nanoscale. According to the TEM images and corresponding diffraction patterns from SPD areas of the 120 min-treatment specimen, the measured grain size near the surface is about 20 - 30 nm. The grain size in deformation layer increases with the depth from the surface, and the nanostructured layer is about 20 μm in depth. Therefore, the surface nanocrystalline and a gradient microstructure from the surface to the matrix are obtained, which results in the micro-hardness decreasing from surface to the matrix gradually.

关键词： surface nanocrystallization shot peening commercial pure Ti

Influence of slip ratio on worn-surface microstructure and fatigue wear behavior of D2 wheel steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2018年第12期25卷 1278-1286页

作者： Chun-peng Liu Xiu-juan Zhao Peng-tao Liu Chong Xu rui-ming ren School of Material Science and Engineering Dalian Jiaotong UniversityDalian 116028LiaoningChina Key Laboratory of Critical Materials of Rail Transportation in Liaoning Province Dalian Jiaotong University Dalian 116028LiaoningChina School of Mechanical Engineering Dalian Jiaotong UniversityDalian 116028LiaoningChina

To investigate the worn-surface microstructure and fatigue cracks in D2 wheel steel under the pure rolling and 0.5% slip ratio conditions,a rolling wear test using a GPM-40 wear machine to simulate the wheel/rail operation was performed. After testing,a transmission electron microscope,a scanning electron microscope with electron backscatter diffraction,and micro-hardness testers were used to characterize the microstructure and fatigue *** surface microstrncture and hardness of the pure rolling sample were in a steady state after 8 × 10^4 cycles;however,the 0.5% slip ratio sample reached a steady state after 7 × 10^3 *** of whether the test uses the slip ratio,the orientation of lamellar pearlites gradually became parallel to the surface and a portion of lamellar cementites was fragmented and dissolved during the formation of steady-state *** slip ratio accelerates this *** hardening mechanism of the samples shows a decrease in the lamellar spacing of pearlite and the refinement of proeutectoid ferrite (PF).As the number of cycles increased,plastic deformation of samples became increasingly severe and the wear mechanism of the samples was fatigue wear in steady *** sample surfaces formed shallow cracks,which gradually peeled *** slip ratio accelerated the initiation and propagation of fatigue cracks because of the high friction stress on the contact *** fatigue cracks initiated at the interface of pearlite and PF and in the PF region.

关键词： D2 wheel steel Slip ratio Wom-surface microstructure Wheel/rail system Rolling wear

Porous sodium titanate nanofibers for high energy quasi-solid-state sodium-ion hybrid capacitors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2022年第7期41卷 2453-2459页

作者： Sheng-Yang Dong Yu-Lin Wu Nan Lv rui-Qi ren Liang Huang Institute of Advanced Materials and Flexible Electronics(IAMFE) School of Chemistry and Materials ScienceNanjing University of Information Science&TechnologyNanjing 210044China Wuhan National Laboratory for Optoelectronics School of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhan 430074China

Sodium-ion hybrid capacitors(SICs)have considered as promising candidate for lithium-ion counterpart in large-scale energy storage due to their advantages of natural abundance,potential low cost,and high energy-power ... 详细信息

关键词： energy fibers Porous