检索结果-南通市图书馆

Macroscopic and microscopic mechanical behaviors of climbing tendrils

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2019年第3期35卷 702-710页

作者： Q.Guo j.j.dong Y.Liu X.h.Xu Q.h.Qin j.S.Wang Tianjin Key Laboratory of Modern Engineering Mechanics Department of MechanicsTianjin UniversityTianjin 300054China State Key Laboratory of Nonlinear Mechanics (LNM) Institute of MechanicsChinese Academy of ScienceBeijing 100080China Research School of Engineering Australian National UniversityCanberraACT 2601Australia

Tendril-bearing climbing plants must recur to the tendril helices with chiral perversion or dual chirality for climbing and to obtain sun exposure. Despite researchers' prolonged fascination with climbing tendrils since Darwin's time and even earlier, why the soft and slender tendrils can bear heavy loads such as the self-weight of a plant or additional load caused by rain remains elusive. In this paper, we take towel gourd tendrils as an example and investigate the macroscopic and microscopic mechanical behaviors of tendrils through experiments and simulations. Our study indicates that the tendril filament exhibits rubber-like hyperelastic behaviors and can particularly endure large elongation, which is mainly attributed to the superelasticity of the cellulose fibril helix contained in the cell wall. Combination of the tendril helical structure with dual chirality or chiral perversion at a macroscale and a cellulose filament helix at a subcellular level creates superior elasticity for biological species relying on support and climbing. This study provides deep insight into the structure-property relationship of climbing tendrils, and the relationship is useful for the bioinspired design of composite systems with superior elasticity.

关键词： Climbing tendril Mechanical behaviors Structure-property relationship Large elongation

Source-network Frequency Cooperative Control and Parameter Optimization Method for high Proportion Renewable Energy UhVDC Feeder Grid

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

Dianwang jishu/Power System Technology 2025年第1期49卷 263-271页

作者： Xie, Yan Tang, Xiaojun dong, Yu Ma, Shiying Shen, jiakai Yan, jianfeng Haidian District Beijing 100192 China State Grid Corporation of China Xicheng District Beijing 100031 China

how to balance the frequency regulation performance and the economic cost to reduce or prevent the system’s generator-tripping and load-shedding is a crucial challenge in enhancing the reliability of high-ratio renewable energy power systems. To explore the power system source-network frequency cooperative control methods, this paper takes renewable energy generators and LCC-hVDC systems as examples, analyzes the frequency regulation principle and control strategy of the main potential resources, and constructs a multi-dimensional evaluation index system for different frequency regulation measures. Further, combining the ideas of global optimization of parameters based on typical scenarios, disturbances and secondary optimization based on actual disturbances, a source-network frequency cooperative control and parameter optimization method based on the comprehensive effectiveness assessment of frequency regulation measures is proposed. Finally, based on the 2023 data of a UhVDC feeder grid and the frequency test data of a typical renewable energy power station, the PSASP software platform is used to construct a simulation model of the region's power grid after calibration. The validation and analysis of the proposed method is carried out for the typical daytime and nighttime operation modes. The results show that the source-network frequency cooperative control and parameter optimization method based on the comprehensive effectiveness assessment of frequency regulation measures proposed in the paper can significantly improve the frequency support capability of the system while considering the economic cost. © 2025 Power System Technology Press. All rights reserved.

关键词： hVDC power transmission

Subpulse Drifting of PSR j1110–5637

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2022年第6期22卷 109-117页

作者： S.j.Dang L.h.Shang L.Lin Q.j.Zhi R.S.Zhao C.B.Wu Z.Y.You A.j.dong j.T.Bai X.Xu D.D.Zhang h.Yang Q.W.Lin School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550001China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550001China School of Physics Science and Technology Xinjiang UniversityUrumqi 830011China

We report a detailed study of polarization characteristics and subpulse drifting in PSR j1110-5637 with the observations of the Parkes 64 m radio telescope at 1369 *** observations revealed that the trailing component of the pulse profile has obvious subpulse drifting,while the leading component has no subpulse *** the two-dimensional fluctuation spectrum(2DFS),we detected three distinct emission modes in the trailing component(modes A,B and C).The emission in mode A is chaotic and indistinguishable,while modes B and C have obvious subpulse *** vertical modulation periods P3of modes B and C are around the mean values of 12 P and 8 P,*** subpulse drifting of PSR j1110-5637 will expand the pulsar sample with multiple subpulse drifting rates,and this will help future systematic studies on the physical origin of the subpulse drifting phenomenon.

关键词： (stars:)pulsars general-(stars:)pulsars individual(PSR j1110-5637)-Stars

Novel insight into dry sliding behavior of Cu-Pb-Sn in-situ composite with secondary phase in different morphology

在线全文

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2020年第5期40卷 158-167页

作者： B.W.dong S.h.Wang Z.Z.dong j.C.jie T.M.Wang T.j.Li School of Material Science and Engineering Dalian University of TechnologyDalian 116024China

The Cu-24 Pb-x Sn(wt%)(x=0,2,4,6)alloys with Pb-rich second-phase particles(SPPs)in different shapes show obviously differently mechanical and self-lubricating *** influence of the SPPs’shape difference on the alloys’mechanical and self-lubricating properties was ***-24 Pb alloy with continuously netty SPPs shows much more intensive stick-slip phenomenon during dry sliding than the other three alloys with independently rodlike *** is mainly due to insufficient lubrication resulted by the netty SPPs’splitting *** the SPPs transforming from netty to rodlike shape under the addition of Sn,the stick-slip phenomenon was notably weakened,which was proven to be related to the higher self-lubricating property of alloys with rodlike ***,the simultaneous increase of ductility and tensile strength was observed in the Cu-24 Pb-x Sn alloys with increasing Sn content,which is because the netty SPPs’splitting behavior will be weakened with them replaced by the rodlike SPPs.

关键词： Second-phase particles Netty shape Rodlike shape Stick-slip Mechanical property Self-lubricating property

基于残差U-net网络的地震资料分辨率提高方法

在线全文

学校读者我要写书评

暂无评论

中国海洋大学学报（自然科学版） 2025年第1期55卷 140-148页

作者：董博艺张进中国海洋大学海洋地球科学学院山东青岛266100 青岛海洋科技中心海洋矿产资源评价与探测技术功能实验室山东青岛266237 中国海洋大学海底科学与探测技术教育部重点实验室山东青岛266100

高分辨率地震资料处理是获取高品质地震资料、实现薄储层良好地震地质解释的关键。传统提高地震分辨率的方法应用条件苛刻,关键参数求取复杂,在实际应用中受到诸多限制。深度学习中的U-net网络以纯数据驱动的优势,可学习低分辨率地震记... 详细信息

高分辨率地震资料处理是获取高品质地震资料、实现薄储层良好地震地质解释的关键。传统提高地震分辨率的方法应用条件苛刻,关键参数求取复杂,在实际应用中受到诸多限制。深度学习中的U-net网络以纯数据驱动的优势,可学习低分辨率地震记录到高分辨率标签的非线性关系,实现地震资料的高分辨率处理。本文设计了残差U-net网络结构,同时提出了基于概率密度函数控制的同分布反射系数集生成方法,将测井反射系数的概率密度函数作为一种先验约束信息融入训练样本,不仅保证了足够的同分布样本来训练网络,还确保了训练样本更符合工区实际情况,以此提高模型预测的准确性。模型测试和实际资料应用结果表明,本文提出的方法能够有效应用于地震资料分辨率的提高,同时拓宽频带。

关键词：提高分辨率 U-net 残差结构同分布

维普期刊数据库博看期刊

公共交往“频道”的校准:媒介化时代我国公共政治交往话语风格的偏误与匡正

在线全文

学校读者我要写书评

暂无评论

新闻与传播评论 2025年第1期78卷 35-45页

作者：董浩骆正林南京林业大学人文社会科学学院江苏南京210037 南京林业大学文旅产业与城市传播研究中心江苏南京210037 南京大学新闻传播学院江苏南京210023

在当今的媒介化时代,随着互联网等新媒体技术对国家、社会不断的赋权与公共政治的崛起,公共交往在越来越便捷、普遍、常态化、多元的同时,也出现了一定的问题。其中,最为突出的问题是公共交往过程中组织机构与公民话语风格的偏误问题。... 详细信息

在当今的媒介化时代,随着互联网等新媒体技术对国家、社会不断的赋权与公共政治的崛起,公共交往在越来越便捷、普遍、常态化、多元的同时,也出现了一定的问题。其中,最为突出的问题是公共交往过程中组织机构与公民话语风格的偏误问题。鉴于此,文章立足于政治媒介化的时代背景,在公共政治视域下,借用话语理论,以我国公共政治交往话语实践的经验与教训为分析样本,以无责漫谈与话语独白为考察中心,探讨匡正当下公共政治交往话语风格偏误的方法与进路。研究认为,组织机构与公民应该积极、主动地进行话语转换,向彼此靠近,消减组织机构话语的话语独白与公民话语的无责漫谈,加速两者之间的话语循环与流通。具体举措包括:话语实践效果的想象与预测、话语的技术化处理、“中间人”的话语斡旋、话语的场域转化、话语的流通与循环、话语的破圈传播、话语的理性规制、话语中社会意见的冶炼、话语实践智慧的提炼等。

关键词：公共交流交流的无奈话语风格偏误无责漫谈话语独白话语理论

Study on the pre-treatment of oxidized zinc ore prior to flotation

在线全文

学校读者我要写书评

暂无评论

International journal of Minerals,Metallurgy and Materials 2018年第2期25卷 117-122页

作者： dong-sheng he Yun Chen Ping Xiang Zheng-jun Yu j.h.Potgieter School of Resource and Civil Engineering Wuhan Institute of TechnologyWuhan 430205China hunan huaqi Resources and Environment Science&Technology Development Co.Ltd. Zhuzhou 412005China School of Chemical and Metallurgical Engineering University of the WitwatersrandJohannesburg 2050South Africa

The pre-treatment of zinc oxide bearing ores with high slime content is important to ensure that resources are utilized optimally. This paper reports an improved process using hydrocyclone de-sliming, dispersion reagents, and magnetic removal of iron minerals for the pre-treatment of zinc oxide ore with a high slime and iron content, and the benefits compared to traditional technologies are shown. In addition, this paper investigates the damage related to fine slime and iron during zinc oxide flotation, the necessity of using hydrocyclone de-sliming together with dispersion reagents to alleviate the influence of slime, and interactions among hydrocyclone de-sliming, reagent dispersion, and magnetic iron removal. Results show that under optimized operating conditions the entire beneficiation technology results in a flotation concentrate with a Zn grade of 34.66% and a recovery of 73.41%.

关键词： zinc oxide ores flotation hydrocyclone de-sliming magnetic deferrization

Ultrasonic-based surface patterning and interfacial reaction of ZrO_(2)ceramics

在线全文

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2023年第24期155卷 202-210页

作者： h.j. dong Z.L. Li X.G.Song j.C. Feng S.j. Wei j.h. Fu Y. Shi State Key Laboratory of Advanced Welding and joining Harbin Institute of Technology Harbin 150001 China Shandong Provincial Key Lab of Special Welding Technology Harbin Institute of Technology at Weihai Weihai 264209 China

We demonstrate a process to achieve selective surface metallization of ZrO_(2)ceramics using ultrasound technology in atmospheric environments at 350℃,which bestows good weldability of ZrO_(2)to achieve rapid and reliable connections with other metals as well as ceramic *** challenge is that brazing or diffusion welding processes to accomplish metallurgical connections for ZrO_(2) typically require holding at elevated temperatures for minutes to hours,while the selective ultrasonic metallization process requires only a few seconds of processing without the application of covering films or solder *** this study,the selected Sn-2Ti alloy could effectively wet and spread on ZrO_(2)substrate under ultrasonication,and continuous interphase layers were rapidly formed in situ between ZrO_(2)and *** bonding strength for the ZrO_(2)/Sn-2Ti interface was well established with the highest shear strength of 37.1 MPa,and the fracture location occurred at the filler *** interfacial reaction layer thickened remarkably with the prolongation of sonication,accompanied by the partial crystallization of amorphous TiO and the formation of irregularly striped Ti_(11.31)Sn_(3)O_(10)nanocrystals.

关键词： Selective ultrasonic metallization Zirconia surface patterning Low temperature connection Sono-oxidation Interfacial reaction

Korean Chungtaejeon tea extract attenuates weight gain in C57BL/6j-Lep ob/ob mice and regulates adipogenesis and lipolysis in 3T3-L1 adipocytes

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

journal of Integrative Medicine 2017年第1期15卷 56-63页

作者： Bhesh Raj Sharma dong Wook Kim dong Young Rhyu Department of Oriental Medicine Resources and Institute of Korean Medicine Industry Mokpo NationalUniversity Jeonnam 534-729 Republic of Korea

OBjECTIVE： Traditional Korean Chungtaejeon （CTj） tea is a type of fermented tea, which has received increasing attention in recent years because of its purported health benefits. The present study was designed to investigate the effect and mechanism of CTj tea extract on body weight gain using C57BL/6j-Lep ob/ob mice and 3T3-L1 adipocytes, respectively. METhODS： The effects of CTj on cell viability, lipid accumulation, and expression of protein and mRNA were measured in 3T3-L1 adipocytes by using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide, oil red O staining, Western blotting, and reverse transcriptase-polymerase chain reaction analyses. C57BL6j-Lep ob/ob mice were administered with CTj （200 or 400 mg/kg body weight） for ten weeks. Then, body weight, food intake, total cholesterol, and triglyceride were measured in ob/ob mice. RESULTS： CTj tea extract treated at 250 wg/mL （CTj250） significantly suppressed lipid accumulation in the differentiated 3T3-L1 adipocytes. Likewise, CTj250 significantly decreased the protein expression of peroxisome proliferator-activated receptor Y （PPARy）, CCj^u~,T/enhancer-binding protein a, and adipocyte lipid- binding protein, and regulated the mRNA expression of PPART, sterol regulatory element-binding protein- lc gene, fatty acid synthase, adipocyte lipid-binding protein, hormone-sensitive lipase, carnitine palmitoyl transferase 1, cluster of differentiation 36, and acetyl-CoA carboxylase in the differentiated 3T3-L1 adipocytes. Mice administered with CTj showed dose-dependent decrease in body weight gain, starting from week 4 of the experiment. CTj tea extract administered at 400 mg/kg body weight significantly decreased fat mass, food efficacy ratio, and levels of plasma triglyceride and total cholesterol. CONCLUSION： CTj attenuated weight gain in ob/ob mice and regulated the activity of the molecules involved in adipogenesis and lipolysis in 3T3-L1 adipocytes. CTj is a potentially valuable herbal therapy for the p

关键词： adipogenesis Chungtaejeon lipolysis C57BL/6j-Lep ob/ob mice weight loss