检索结果-南通市图书馆

Optimum Tilt Angle of Flow Guide in Steam Turbine Exhaust Hood Considering the Effect of Last Stage Flow Field

Chinese Journal of Mechanical Engineering 2017年第4期30卷 866-875页

作者： Lihua cao Aqiang LIN Yong LI bin XIAO School of Energy and Power Engineering Northeast Dianli UniversityJilin 132012China

Abstract Heat transfer and vacuum in condenser are influenced by the aerodynamic performance of steam tur- bine exhaust hood. The current research on exhaust hood is mainly focused on analyzing flow loss and optimal design of its structure without consideration of the wet steam condensing flow and the exhaust hood coupled with the front and rear parts. To better understand the aerodynamic performance influenced by the tilt angle of flow guide inside a diffuser, taking a 600 MW steam turbine as an example, a numerical simulator CFX is adopted to solve compressible three-dimensional （3D） Reynolds time-aver- aged N-S equations and standard k-e turbulence model. And the exhaust hood flow field influenced by different tilt angles of flow guide is investigated with consideration of the wet steam condensing flow and the exhaust hood coupled with the last stage blades and the condenser throat. The result shows that the total pressure loss coefficient and the static pressure recovery coefficient of exhaust hood change regularly and monotonously with the gradual increase of tilt angle of flow guide. When the tilt angle of flow guide is within the range of 30~ to 40~, the static pressure recovery coefficient is in the range of 15.27% to 17.03% and the total pressure loss coefficient drops to approximately 51%, the aerodynamic performance of exhaust hood is significantly improved. And the effectiveenthalpy drop in steam turbine increases by 0.228% to 0.274%. It is feasible to obtain a reasonable title angle of flow guide by the method of coupling the last stage and the condenser throat to exhaust hood in combination of the wet steam model, which provides a practical guidance to flow guide transformation and optimal design in exhaust hood.

关键词： Steam turbine Exhaust hood Last stageblades Tilt angle of flow guide Aerodynamicperformance

来源：

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

Adaptive Robust Tracking Control of Pressure Trajectory Based on Kalman Filter

引用

Chinese Journal of Mechanical Engineering 2009年第3期22卷 433-439页

作者： cao Jian ZHU Xiaocong TAO Guoliang YAO bin The State Key Lab of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China School of Mechanical Engineering Purdue University Lafayette IN 47907 USA

When adaptive robust control（ARC） strategy based on backstepping design is applied in pneumatic servo control, accurate pressure tracking in motion is especially necessary for both force and position trajectories tracking ofrodless pneumatic cylinders, and therefore an adaptive robust pressure controller is developed in this paper to improve the tracking accuracy of pressure trajectory in the chamber when the pneumatic cylinder is moving. In the proposed adaptive robust pressure controller, off-line fitting of the orifice area and on-line parameter estimation of the flow coefficient are utilized to have improved model compensation, and meanwhile robust feedback and Kalman filter are used to have strong robustness against uncertain nonlinearities, parameter fluctuations and noise. Research results demonstrate that the adaptive robust pressure controller could not only track various pressure trajectories accurately even when the pneumatic cylinder is moving, but also obtain very smooth control input, which indicates the effectiveness of adaptive model compensation. Especially when a step pressure trajectory is tracked under the condition of the movement of a rodless pneumatic cylinder, maximum tracking error of ARC is 4.46 kPa and average tracking error is 0.99 kPa, and steady-state error of ARC could achieve 0.84 kPa, which is very close to the measurement accuracy of pressure transducer.

关键词： pneumatic servo control adaptive robust control Kalman filter orifice area

来源：

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

Impact pressure of waves generated by landslides on bank slopes

引用

Journal of Mountain Science 2024年第3期21卷 918-931页

作者： cao ting WANG Pingyi QIU Zhenfeng LIU Jie Key Laboratory of Hydraulic and Waterway Engineering of Ministry of Education Chongqing Jiaotong UniversityChongqing 400074China Engineering Research Center of Diagnosis Technology and Instruments of Hydro-Construction Chongqing Jiaotong UniversityChongqing 400074China

Impulse waves that are generated by landslides in narrow reservoir areas threaten the stability of buildings and bank *** discuss the action process and evolution law of the wave pressure on bank slopes,a three-dimensional physical model test that considers impulse waves generated by landslides was performed,and factors including landslide width,thickness,slope angles of the sliding surface,and bank slope angle were *** on wave forms on the bank slopes,wave pressure curve characteristics,and peak value,the action process of wave pressure could be divided into the following stages:maximum pulsating pressure stage,wave impact stage(when waves break),and stationary pulsation *** was found that wave breaking is dependent on the value of the surf similarity parameterξ.The distribution pattern of impact pressure decays linearly on both sides of the maximum impact pressure point,and the attenuation degree decreases when it attains 40%of the maximum ***,it is proposed that the prediction formula for the maximum effective impact pressure of the bank slope be related to the reciprocal of wave steepness,relative water depth,and slope *** prediction formula provides strong theoretical support for early safety warning and for predicting the bank slope under impulse waves generated by landslides.

关键词： Model test Impact pressure Action stage Breaking discrimination Distribution model

来源：

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

Adaptive 5G-and-beyond network-enabled interpretable federated learning enhanced by neuroevolution

引用

Science China(Information Sciences) 2024年第7期67卷 107-132页

作者： bin cao Jianwei ZHAO Xin LIU Yun LI State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology School of Artificial Intelligence Hebei University of Technology School of Economics and Management Hebei University of Technology Industrial Artificial Intelligence Centre Shenzhen Institute for Advanced StudyUniversity of Electronic Science and Technology of China

Mobile telemedicine systems based on the next-generation communication will significantly enhance deep fusion of network automation and federated learning(FL), but data privacy is a paramount issue in sectors like healthcare. This work hence considers FL augments 5G-and-beyond networks by training deep learning(DL) models without the need to exchange raw data. The substantial communication loads imposed on by extensive parameters involved in DL models are managed through adaptive scheduling mechanisms effectively. To address the opaque nature of DL models and to improve the interpretability of FL models, we introduce a convolutional fuzzy rough neural network specifically designed for medical image processing. We also develop a multiobjective memetic evolutionary algorithm to streamline and optimize the neural network architectures. Our comprehensive FL framework integrates smart scheduling, interpretable fuzzy rough logic,and neuroevolution. This framework is shown to improve communication efficiency, increase interpretability of diagnosis with protected privacy, and generate low-complexity neural architectures.

关键词： 5G-and-beyond network interpretable federated learning mobile telemedicine system fuzzy rough set theory neuroevolution

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Focusing Solar Spectrum by Anthracene Molecules

引用

Wuhan University Journal of Natural Sciences 2018年第5期23卷 412-417页

作者： cao ting LIU Lijian College of Chemistry and Molecular Sciences Wuhan University

Conventionally, each fluorophore is only clarified with the wavelength of incident beam shorter（down-conversion） or longer（up-conversion） than that of emission light. However, three anthracenes presented in this paper are the wavelength-focused（WF） molecules which can shift the portions of shorter and longer wavelengths of incident light into an identical wavelength in between. UV（ultraviolet） and NIR（near infrared） portions of Xenon light-simulated solar spectrum are focused into visible light with maximum wavelengths ranging from 415 to 471 nm through the two-way photoluminescence of the three anthracenes（anthracene（AN）, fluoranthene（FLA） and 9, 10-diphenylanthracene（DPA））. At the same time, the intensity of the visible light is two times as that of excitation light. Besides, DPA dissolved in different solvents shows excellent fluorescence features. The results present great potential for applications in enhancing the intensity of solar spectrum at visible region and utilizing more portions of sunlight with solar cell.

关键词： focusing solar spectrum two-way conversion an-thracene

来源：

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

Rational design of lipid-activatable NIR-II probes for precisely imaging atherosclerotic plaque

引用

Science China Chemistry 2025年

作者： Xinyu Xu Yuan Ma Hui cao Li Xu Haoming Chen Sulai Liu Wei Sun Guosheng Song Xiaobing Zhang State Key Laboratory for Chemo/Bio-Sensing and Chemometrics College of Chemistry and Chemical EngineeringHunan University Department of Hepatobiliary Surgery/Central Laboratory Hunan Provincial People's Hospital (The First Affiliated Hospital of Hunan Normal University) Department of Cardiology the First Affiliated Hospital of Nanjing Medical University Key Laboratory of Targeted Intervention of Cardiovascular Disease Collaborative Innovation Center for Cardiovascular Disease Translational MedicineNanjing Medical University Shenzhen Research Institute of Hunan University

Atherosclerosis(AS) is a prevalent condition associated with cardiovascular and cerebrovascular diseases, featuring lipid-laden plaque; however, the insufficient resolution and low sensitivity of traditional medical imaging techniques limit their application in lipid imaging. Currently, the second near-infrared(NIR-II) fluorescence imaging offers promising sensitivity and convenience. However, existing probes have limitations in terms of signal-to-background ratio, penetration depth, and tissue scattering. Herein, we use a molecular regulatory strategy to design a lipid-activatable probe Rh-965 with high specificity and NIR-II emission for improved imaging potential in deep tissues. The potential of Rh-965 for imaging plaque lipids in mice with AS is demonstrated by localizing carotid artery plaques using NIR-II imaging. The development of more stable lipid-activated NIR-II probes can significantly enhance atherosclerosis diagnosis and facilitate in vivo imaging in deeper tissues.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Mobile CRISPR-Cas9 based anti-phage system in E. coli

引用

Frontiers of Chemical Science and Engineering 2022年第8期16卷 1281-1289页

作者： Zhou cao Yuxin Ma bin Jia Ying-Jin Yuan Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering(Ministry of Education) Tianjin UniversityTianjin 300072China Collaborative Innovation Center of Chemical Science and Engineering(Tianjin) School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China

Escherichia coli is one of the most important microbial cell factories,but infection by bacteriophages in the environment may have a huge impact on its application in industrial ***,we developed a mobile CRISPR-Cas9 based anti-phage system for bacteriophages defense in *** conjugative plasmids pGM1(phosphoglucomutase 1)and pGM2 carrying one and two guide RNAs,respectively,were designed to defend against a filamentous *** results showed that the pGM1 and pGM2 could decrease the phage infection rate to 1.6%and 0.2%respectively in infected *** preventing phage infection in ***,the pGM2 decreased the phage infection rate to 0.1%,while pGM1 failed to block phage *** verification revealed that point mutations in protospacer or protospacer adjacent motif sequences of the phage genome caused loss of the defense *** results support the potential application of MCBAS in *** cell factories to defend against phage infections.

关键词： phage infections anti-phage CRISPR-Cas9,conjugative transfer synthetic biology

来源：

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

Bolt insertion damage and mechanical behaviors investigation of CFRP/CFRP interference fit bolted joints

引用

Chinese Journal of Aeronautics 2022年第9期35卷 354-365页

作者： Yangjie ZUO ting YUE Ruisong JIANG Zengqiang cao Liu YANG School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065China Xi’an Space Engine Co.Ltd Xi'an 710100China School of Mechanical Engineering Northwestern Polytechnical UniversityXi'an 710072China Xi’an ASN Technology Group Co.Ltd Xi'an 710072China

Interference fit has advantages in improving fatigue behaviors of composite bolted joints,however, interference fit bolt insertion tends to cause damages in laminates weakening joint mechanical properties. Therefore, an experimental study was conducted to investigate bolt insertion damages of Carbon Fiber Reinforced Polymer(CFRP)/CFRP interference fit bolted *** behaviors of joints were also evaluated experimentally under both quasi-static loads and cyclic loads. Scanning Electron Microscope(SEM) and high-resolution X-ray micro-CT scan were used to examine micro damages in laminates. Damage and failure behaviors of joints were characterized. The results demonstrated that the hole entrance in upper laminate and the laminate boundary near the hole wall were the most critical regions for damages during bolt insertions. However, the influence of those damages on quasi-static failure loads and fatigue failure modes of joints was minimal. Delamination and matrix cracking occurred first in laminates following fiber and matrix fracture in quasi-static tensile tests. Interference fit could improve the fatigue resistance of the laminate hole, however, the bolt seemed to suffer a more critical local fatigue loading *** paper can contribute to composite structure designs, especially in understanding damage and failure behaviors of composite bolted joints.

关键词： Bolted joints Composite Damage Failure Fatigue life Interference fit

来源：

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

Scleral TGF-β1 and Smad3 expression is altered by TCM Bu Jing Yi Shi Tablets in guinea pigs with form-deprivation myopia

引用

Journal of Traditional Chinese Medical Sciences 2016年第2期3卷 124-132页

作者： Ya Mo Yi Wang bin cao Jiajia Zhang Guoting Ren ting Yang Department of Ophthalmology The Affiliated Hospital of Chengdu University of TCMChengdu 610072China Department of Pathology The Affiliated Hospital of Chengdu University of TCMChengdu 610072China

Objective:To explore whether the traditional Chinese medicine(TCM)Bu Jing Yi Shi Tablets alters the expression of scleral TGF-b1 and Smad3 in guinea pigs with formdeprivation myopia(FDM).Methods:Sixty-five guinea pigs were randomly divided into control,model,low-,medium-,and high-dose treatment *** for the control group,FDM was induced by covering the right eye of each animal with opaque *** treatment groups were gavaged with different suspension concentrations of Bu Jing Yi Shi *** and axial length were performed before and after myopia *** the end of the experiment,all right eyes were extracted,and scleral sections were prepared for staining and TGF-b1 and Smad3 *** thickness and area,the scleral fibroblast quantity,and scleral TGFb1 and Smad3 expressions were ***:The 5 FDM groups had the same initial axial length and diopter,the final diopter and axial length of the model group were significantly increased compared with the control group and treatment groups(P<.01).The axial length of each treatment group decreased as the dose decreased compared with the model group(P<.01);the total scleral area(P<.05 e.01)and the number of scleral fibroblasts(P<.01)in the model group were significantly lower than the treatment *** the TGF-b1 and Smad3 integral optical densities in the model group were significantly lower than the control and medium-and high-dose treatment groups(P<.01).TGF-b1 and Smad3 mRNAs in the model group were decreased compared with the control group,but increased in expression after treatment.

关键词： TCM Form-deprivation myopia Sclera TGF-b1 Smad3

来源：

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

Modeling leaf color dynamics of winter wheat in relation to growth stages and nitrogen rates

引用

Journal of Integrative Agriculture 2022年第1期21卷 60-69页

作者： ZHANG Yong-hui YANG Yu-bin CHEN Chun-lei ZHANG Kui-ting JIANG Hai-yan cao Wei-xing ZHU Yan School of Computer Engineering Weifang UniversityWeifang 261061P.R.China Texas A&M University System AgriLife Research&Extension CenterBeaumontTX 77713United States College of Information Science and Technology Nanjing Agricultural UniversityNanjing 210095P.R.China National Engineering and Technology Center of Information Agriculture Nanjing Agricultural UniversityNanjing 210095P.R.China

The objective of this work was to develop a model for simulating the leaf color dynamics of winter wheat in relation to crop growth stages and leaf positions under different nitrogen(N) rates. RGB(red, green and blue) data of each main stem leaf were collected throughout two crop growing seasons for two winter wheat cultivars under different N rates. A color model for simulating the leaf color dynamics of winter wheat was developed using the collected RGB values. The results indicated that leaf color changes went through three distinct stages, including early development stage(ES), early maturity stage(MS) and early senescence stage(SS), with respective color characteristics of light green, dark green and yellow for the three stages. In the ES stage, the R and G colors gradually decreased from their initial values to steady values, but the B value generally remained unchanged. RGB values remained steady in the MS, but all three gradually increased to steady values in the SS. Different linear functions were used to simulate the dynamics of RGB values in time and space.A cultivar parameter of leaf color matrix(MRGB) and a nitrogen impact factor(FN) were added to the color model to quantify their respective effects. The model was validated with an independent experimental dataset. RMSEs(root mean square errors) between the observed and simulated RGB values ranged between 7.0 and 10.0, and relative RMSEs(RRMSEs)ranged between 7 and 9%. In addition, the model was used to render wheat leaves in three-dimensional space(3 D). The 3 D visualizations of leaves were in good agreement with the observed leaf color dynamics in winter wheat. The developed color model could provide a solid foundation for simulating dynamic crop growth and development in space and time.

关键词： winter wheat crop model virtual crop leaf color crop phenotype RGB Model

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：