检索结果-南通市图书馆

Temperature gradient driving interdiffusion interface and composition evolution in Ni-AI-Cr alloys

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2022年第9期41卷 3186-3196页

作者： Yong-Sheng Li Hui-Yu Wang Jing Chen Shuai-ge yang Peng Sang Hong-Li Long School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing210094China Key Laboratory of Advanced Metallic and Intermetallic Materials Technology Ministry of Industry and Information Technology of People’s Republic of ChinaNanjing210094China

The interdiffusion interface microstructures and composition evolution of Ni-Al-Cr/Ni-Al-Cr layered alloys under different temperature gradients were studied using phase-field simulation.A precipitate-free zone forms near the interface of the layered alloys,and the interface does not move with time under temperature *** Cr concentrations in the alloy layers are different,Al diffuses from a low-to high-temperature region,whereas Cr from a high-to low-temperature *** width of the precipitate-free zone changes from 0.5 to 2.5μm as the temperature gradient changes fromΔT=0.625 K·μm^(−1) to 1.250 K·μm^(−1);the width of the interdiffusion zone is also ***,the temperature gradient promotes the interdiffusion of elements through the *** contrast,when the initial Al concentration is different in the alloy layers,an uphill diffusion of Al occurs,which is driven by the chemical potential of Al.

关键词： Superalloy Interdiffusion Interface microstructure Phase-field

Analysis of physical properties of gas hydrate-bearing unconsolidated sediment samples from the ultra-deepwater area in the South China Sea

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2022年第3期16卷 509-520页

作者： Xin Lyu Qingping Li yang ge Min Ouyang Hexing Liu Qiang Fu Junlong Zhu Shouwei Zhou China National Offshore Oil Corporation Research Institute Co.Ltd. Beijing 100028China State Key Laboratory of Natural Gas Hydrate Beijing100028China Zhanjiang Branch of China National Offshore Oil Corporation(CNOOC)Limited Zhanjiang524057China China National Offshore Oil Corporation(CNOOC) Beijing100021China

Marine natural gas hydrate has recently attracted global attention as a potential new clean energy source. Laboratory measurements of various physical properties of gas hydrate-bearing marine sediments can provide valuable information for developing efficient and safe extraction technology of natural gas hydrates. This study presents comprehensive measurement results and analysis of drilled hydrate-bearing sediments samples recovered from Qiongdongnan Basin in the South China Sea. The results show that the gas hydrate in the core samples is mainly methane hydrate with a methane content of approximately 95%, and the other components are ethane and carbon dioxide. The saturation of the samples fluctuates from 2%–60%, the porosity is approximately 38%–43%, and the water content is approximately 30%–50%, which indicate that high water saturation means that timely drainage should be paid attention to during hydrate extraction. In addition, the median diameter of the sediment samples is mainly distributed in the range of 15 to 34 µm, and attention should be paid to the prevention and control of sand production in the mining process. Moreover, the thermal conductivity is distributed in the range of 0.75 to 0.96 W/(m·K) as measured by the flat plate heat source method. The relatively low thermal conductivity of hydrates at this study site indicates that a combined approach is encouraged for natural gas production technologies. It is also found that clay flakes and fine particles are attached to the surface of large particles in large numbers. Such characteristics will lead to insufficient permeability during the production process.

关键词： natural gas hydrates physical properties analysis hydrate-bearing sediments

Experimental Researches on Milled Wood Lignin Pyrolysis Based on Analysis of Bio-oil

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2011年第3期27卷 426-430页

作者： GUO Xiu-juan WANG Shu-rong WANG Kai-ge LUO Zhong-yang State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou 310027 P. R. China

The structure of milled wood lignin（MWL）, isolated via the Bjrkman procedure, was studied by means of 1H NMR spectroscopy and Fourier transform infrared spectroscopy, and then its pyrolytic product distribution was investigated on a pyrolysis device. MWL obtained from Manchurian Ash（MA） contained more methoxyl and free phenolic hydroxyl groups per C9 unit than MWL from Mongolian Pine（MP） due to the existence of both guaiacyl and syringyl units, which have a major influence on the pyrolysis behavior of lignin. The results of pyrolysis show that MWL from MA generated a higher yield of bio-oil, mainly composed of phenols, guaiacols, syringols and catechols, and a less yield of char, in addition to the gaseous products CO, CO2, methane and methanol, compared with MWL from MP. Guaiacol and syringol were the typical products from G-lignin and S-lignin, probably attributed to the easier cleavage of the aryl-alkyl linkage in the side chain compared with the C―OCH3 bond in the benzene ring. The degradation of MWL from MP was dominated by the demethylation reaction and the cleavage of aliphatic ―CH2OH at the γ-position, followed by the cracking of the Cα―Cβ and C4―Cα bonds.

关键词： Pyrolysis Milled wood lignin(MWL) Guaiacyl unit Syringyl unit

Novel, Green, Simple and Uncatalyzed Route for High Yield Preparation of Benzaldehyde Glycol Acetal

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2011年第5期27卷 799-802页

作者： TANG Jia SONG Ji-yuan WANG ge yang Mu GUO Wan-chun School of Material Science and Engineering University of Science and Technology Beijing Beij＇ing 100083 P. R. China

A simple approach for the condensation of benzaldehyde with ethylene glycol was adopted without employing any catalyst. The study reveals that factors including temperature, molar ratio of reactants, and the water removal significantly influence the conversion ratio of benzaldehyde. The results indicate that the use of optimal reaction conditions such as temperature and water removing exhibits more pronounced effects on the conversion ratio of benzaldehyde compared with the use of catalysts. In a word, a green and simple method for the condensation of aldehyde and menthandiol has been devised and investigated.

关键词： Condensation Benzaldehyde Ethylene glycol

Sulfur and carbon co-doped g-C_(3)N_(4)microtubes with enhanced photocatalytic H2 production activity

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2024年第1期18卷 110-121页

作者： yang ge Quanhao SHEN Qi ZHANG Naixu LI Danchen LU Zhaoming ZHANG Zhiwei FU Jiancheng ZHOU School of Chemistry and Chemical Engineering Southeast UniversityNanjing 211189China Shangdong Yellow Triangle Biotechnology Industry Research Institute Co. Ltd.Dongying 257091China Xuzhou B&C Chemical Co. Ltd.Xuzhou 221300China

Metal-free graphitic carbon nitride(g-C_(3)N_(4))has captured significant attention as a low-cost and efficient hydrogen production photocatalyst *** regulating the microstructure and accelerating the separation of photogenerated carriers remain crucial strategies for promoting the photocatalytic performance of this ***,a novel sulfur–carbon co-doped g-C_(3)N_(4)(SCCN)hierarchical microtubules filled with abundant nanosheets inside by thermal polymerization is *** nanosheets create abundant pores and cavities inside the SCCN microtubes,thereby increasing the specific surface area of g-C_(3)N_(4)and providing sufficient reactant attachment ***,the hierarchical structure of SCCN microtubules strengthens the reflection and scattering of light,and the utilization of visible light is favorably *** importantly,co-doping S and C has greatly improved the photocatalytic performance of graphitic carbon nitride,optimized the band gap structure and enhanced the photogenerated carrier ***,the SCCN exhibits a remarkable photocatalytic H_(2)evolution rate of 4868μmol/(g·h).This work demonstrates the potential of multi-nonmetal doped g-C_(3)N_(4)as the ideal photocatalyst for H2 evolution.

关键词： carbon nitride photocatalysis hydrogen production

Exosomal CD44 Cooperates with Integrin a6b4 to Support Organotropic Metastasis via Regulating Tumor Cell Motility and Target Host Cell Activation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Engineering 2021年第10期7卷 1413-1423页

作者： Wei Mu Yajie Xu Pengfei Gu Wenbo Wang Jingquan Li yang ge Hui Wang Center for Single-Cell Omics School of Public HealthShanghai Jiao Tong University School of MedicineShanghai 200025China CAS Key Laboratory of Nutrition Metabolism and Food SafetyShanghai Institute of Nutrition and HealthChinese Academy of SciencesShanghai 200031China National Research Center for Translational Medicine Shanghai Jiao Tong University School of MedicineShanghai 200031China

Rapid metastasis to vital organs such as the lung,liver,and brain is responsible for the vast majority of pancreatic cancer *** metastasis of pancreatic cancer accounts for the high mortality rate in *** derived from pancreatic cancer cells tend to be enriched in proteins that are anchored to the cell membrane,supporting the reprogramming of the tumor microenvironment and the progression of distant metastatic *** the first time,our study has demonstrated that cluster of differentiation 44(CD44),a transmembrane glycoprotein delivered by exosomes,is involved in the metastatic process of pancreatic ***,CD44 was found to interact with integrin a6b4 to form a complex,thereby remodeling intracellular skeleton proteins,and to promote tumor cell motility through the activation of the Src and Ras signaling ***,we also demonstrated that the CD44–a6b4 complex can be delivered to the target region via the paracrine effects of *** selective uptake of CD44-competent tumor exosomes by liver cells activated fibrotic pathways and generated a pre-metastatic niche by stimulating the cytokines,proinflammatory factors,and growth factors that ultimately support tumor *** results suggest the potential application of exosomal CD44 as a biomarker for the clinical diagnosis of and therapy for pancreatic cancer.

关键词： Pancreatic cancer Organotropic metastasis Exosomes Pre-metastatic niche CD44

Prediction of TBM Penetration Rate Based on The Model of PLS-FNN

在线全文

学校读者我要写书评

暂无评论

Prediction of TBM Penetration Rate Based on The Model of PLS...

Performance enhancement of a viscoelastic bistable energy harvester using time-delayed feedback control

第25届中国控制与决策会议

作者： Fei Ling Wang Jingcheng ge yang Li Chuang Zhang Langwen Department of Automation Shanghai Jiaotong University and Key Laboratory of System Control and Information Processing Ministry Of Education Of China

ISBN: (纸本)9781467355339

Many researches on the prediction of the penetration rate of the tunneling boring machine （TBM） have been carried out. The prediction of the penetration rate will contribute to reduce the danger of TBM construction, decrease the cost and provide the support for the construction planning. Most methods for predicting penetration rate rely on the fixed equation relationship between the input parameters and output parameters. In this paper, we build up a dynamic model. We mainly make use of the partial least squares regression algorithm （PLS） and the structure of the fuzzy-neuron network （FNN） to build up the model. All the data should be normalized. We randomly select 120 groups of the data from TBM construction as the training data and 33 groups of data as the testing data. The training and testing results are analyzed by the mean square error and the correlation coefficient. At the same time, we compare the prediction of the PLS-FNN model with the prediction of the FNN model. The simulation result shows that the PLS-FNN model has the good performance for the prediction.

关键词： TBM Rate Of Penetration PLS Fuzzy-Neuron Network

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第6期33卷 142-154页

作者：黄美玲杨勇歌刘洋 School of Mathematics and Statistics Guangdong University of TechnologyGuangzhou 510520China State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong UniversityXi'an 710049China Exeter Small-Scale Robotics Laboratory Engineering DepartmentUniversity of ExeterNorth Park RoadExeter EX44QFUK

This paper focuses on the stochastic analysis of a viscoelastic bistable energy harvesting system under colored noise and harmonic excitation, and adopts the time-delayed feedback control to improve its harvesting efficiency. Firstly, to obtain the dimensionless governing equation of the system, the original bistable system is approximated as a system without viscoelastic term by using the stochastic averaging method of energy envelope, and then is further decoupled to derive an equivalent system. The credibility of the proposed method is validated by contrasting the consistency between the numerical and the analytical results of the equivalent system under different noise conditions. The influence of system parameters on average output power is analyzed, and the control effect of the time-delayed feedback control on system performance is compared. The output performance of the system is improved with the occurrence of stochastic resonance(SR). Therefore, the signal-to-noise ratio expression for measuring SR is derived, and the dependence of its SR behavior on different parameters is explored.

关键词： energy harvesting bistability stochastic averaging method stochastic resonance time-delayed feedback control

An Adaptive Obstacle Avoidance Algorithm for Unmanned Surface Vehicle in Complicated Marine Environments

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2014年第4期1卷 385-396页

作者： Rubo Zhang Pingpeng Tang Yumin Su Xueyao Li ge yang Changting Shi the College of Computer Science and Technology Harbin Engineering UniversityHarbin 150001China College of Electromechanical and Information Dalian Nationalities University the College of Computer Science and Technology Harbin Engineering UniversityHarbin 150001China Wuhan Second Ship Design and Research Institute the National Key Laboratory of Science and Technology on Autonomous Underwater Vehicle Harbin Engineering University

Unmanned surface vehicles(USVs) are important autonomous marine robots that have been studied and gradually applied into practice. However, the autonomous navigation of USVs, especially the issue of obstacle avoidance in complicated marine environment, is still a fundamental problem. After studying the characteristics of the complicated marine environment, we propose a novel adaptive obstacle avoidance algorithm for USVs,based on the Sarsa on-policy reinforcement learning *** proposed algorithm is composed of local avoidance module and adaptive learning module, which are organized by the “divide and conquer” strategy-based architecture. The course angle compensation strategy is proposed to offset the disturbances from sea wind and currents. In the design of payoff value function of the learning strategy, the course deviation angle and its tendency are introduced into action rewards and penalty policies. The validity of the proposed algorithm is verified by comparative experiments of simulations and sea trials in three sea-state marine environments. The results show that the algorithm can enhance the autonomous navigation capacity of USVs in complicated marine environments.

关键词： Algorithm design and analysis Collision avoidance Learning (artificial intelligence) Marine technology Mobile robots Navigation Sea surface Unmanned aerial vehicles “divide and conquer” strategy Sarsa on-policy reinforcement learning algorithm Unmanned surface vehicle adaptive obstacle avoidance algorithm complicated marine environment Obstacle avoidance vehicle UNMANNED sublittoral zone Unmanned Aerial Vehicle Algorithm design and analysis Divide and conquer navigation Marine technology Ground vehicles drone honey bees Collision avoidance algorithms sea surface Mobile robots