检索结果-南通市图书馆

Bidirectional rotating direct-current triboelectric nanogenerator with self-adaptive mechanical switching for harvesting reciprocating motion

引用

International Journal of Extreme Manufacturing 2024年第4期6卷 324-335页

作者： Donghan Lee Joonmin Chae Sumin Cho Jong Woo Kim Awais Ahmad Mohammad Rezaul Karim Moonwoo La Sung Jea Park Dongwhi Choi Department of Mechanical Engineering(Integrated Engineering Program) Kyung Hee University1732 Deogyeong-daeroYonginGyeonggi 17104Republic of Korea Department of Chemistry University of LahoreLahorePakistan Department of Mechanical Engineering College of EngineeringKing Saud UniversityRiyadh 11421Saudi Arabia School of Mechanical Engineering Korea University of Technology and Education1600 Chungjeol-roCheonanChungnam 31253Republic of Korea

Amid the growing interest in triboelectric nanogenerators(TENGs)as novel energy-harvesting devices,several studies have focused on direct current(DC)TENGs to generate a stable DC output for operating electronic ***,owing to the working mechanisms of conventional DC TENGs,generating a stable DC output from reciprocating motion remains a ***,we propose a bidirectional rotating DC TENG(BiR-TENG),which can generate DC outputs,regardless of the direction of rotation,from reciprocating *** distinct design of the BiR-TENG enables the mechanical rectification of the alternating current output into a rotational-direction-dependent DC ***,it allows the conversion of the rotational-direction-dependent DC output into a unidirectional DC output by adapting the configurations depending on the rotational *** to these tailored design strategies and subsequent optimizations,the BiR-TENG could generate an effective unidirectional DC *** of the BiR-TENG for the reciprocating motions of swinging doors and waves were demonstrated by harnessing this *** study demonstrates the potential of the BiR-TENG design strategy as an effective and versatile solution for energy harvesting from reciprocating motions,highlighting the suitability of DC outputs as an energy source for electronic devices.

关键词： direct-current triboelectric nanogenerator mechanical rectification self-adaptive mechanical design harvesting reciprocation motion

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

Mapping of moraine dammed glacial lakes and assessment of their areal changes in the central and eastern Himalayas using satellite data

引用

Journal of Mountain Science 2019年第1期16卷 77-94页

作者： Sazeda BEGAM Dhrubajyoti SEN School of Water resources Indian Institute of Technology Kharagpur Department of Civil Engineering Indian Institute of Technology Kharagpur

The relatively rapid recession of glaciers in the Himalayas and formation of moraine dammed glacial lakes(MDGLs) in the recent past have increased the risk of glacier lake outburst floods(GLOF) in the countries of Nepal and Bhutan and in the mountainous territory of Sikkim in India. As a product of climate change and global warming, such a risk has not only raised the level of threats to the habitation and infrastructure of the region, but has also contributed to the worsening of the balance of the unique ecosystem that exists in this domain that sustains several of the highest mountain peaks of the world. This study attempts to present an up to date mapping of the MDGLs in the central and eastern Himalayan regions using remote sensing data, with an objective to analyse their surface area variations with time from 1990 through 2015, disaggregated over six episodes. The study also includes the evaluation for susceptibility of MDGLs to GLOF with the least criteria decision analysis(LCDA). Forty two major MDGLs, each having a lake surface area greater than 0.2 km2, that were identified in the Himalayan ranges of Nepal, Bhutan, and Sikkim, have been categorized according to their surface area expansion rates in space and time. The lakes have been identified as located within the elevation range of 3800 m and6800 m above mean sea level(a msl). With a total surface area of 37.9 km2, these MDGLs as a whole were observed to have expanded by an astonishing 43.6% in area over the 25 year period of this study. A factor is introduced to numerically sort the lakes in terms of their relative yearly expansion rates, based on their interpretation of their surface area extents from satellite imageries. Verification of predicted GLOF events in the past using this factor with the limited field data as reported in literature indicates that the present analysis may be considered a sufficiently reliable and rapid technique for assessing the potential bursting susceptibility of the MDGLs.

关键词： Glacier retreat Lakes mapping Moraine dammed glacial lake(MDGL) Surface area change of lakes Landsat imagery data Least criteria decision analysis(LCDA)

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

Optimal Control of a Mackerel-Mimicking Robot for Energy Efficient Trajectory Tracking

引用

Journal of Bionic Engineering 2007年第4期4卷 209-215页

作者： Seunghee Lee Jounghyun Park Cheolheui Han Department of Mechanical Engineering Hanyang University Seoul 133-791 Korea Department of Aeronautical and Mechanical Design Engineering Chungju National University Chungju 380-702 Korea

A robotic fish, BASEMACK1, is designed and fabricated by mimicking the shape of a live mackerel. Three DC servo-motors are serially linked together and actuated to mimic the mackerel＇s Carangiform motion. Hydrodynamic characteristics of a fish-mimetic test model are experimentally identified and utilized in order to numerically simulate fish swimming. The discrete set of kinematic and dynamic parameters are obtained by considering required horizontal and lateral forces and minimum energy consumption. Using the optimized parameter set, optimal control of the robot is studied.

关键词： mackerel-mimicking robot optimal control trajectory tracking

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

Wave dynamic processes in cellular detonation reflection from wedges

引用

Acta Mechanica Sinica 2007年第1期23卷 33-41页

作者： Zongmin Hu Zonglin Jiang LHD institute of Mechanics CAS Beijing 100080 China ReCAPT Gyeongsang National University Jinju Kyeongnam 660-701 South Korea

When the cell width of the incident detonation wave （IDW） is comparable to or larger than the Mach stem height, self-similarity will fail during IDW reflection from a wedge surface. In this paper, the detonation reflection from wedges is investigated for the wave dynamic processes occurring in the wave front, including transverse shock motion and detonation cell variations behind the Mach stem. A detailed reaction model is implemented to simulate two-dimensional cellular detonations in stoichiometric mixtures of H2/O2 diluted by Argon. The numerical results show that the transverse waves, which cross the triple point trajectory of Mach reflection, travel along the Mach stem and reflect back from the wedge surface, control the size of the cells in the region swept by the Mach stem. It is the energy carried by these transverse waves that sustains the triple-wave-collision with a higher frequency within the over-driven Mach stem. In some cases, local wave dynamic processes and wave structures play a dominant role in determining the pattern of cellular record, leading to the fact that the cellular patterns after the Mach stem exhibit some peculiar modes.

关键词： Cellular detonation Wedge Reflection Wave dynamics Simulation

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

Cortex cinnamomi extract prevents streptozotocin- and cytokine-induced β-cell damage by inhibiting NF-κB

引用

World Journal of Gastroenterology 2006年第27期12卷 4331-4337页

作者： Kang-Beom Kwon Eun-Kyung Kim Eun-Sil Jeong Young-Hoon Lee Young-Rae Lee Jin-Woo Park Do-Gon Ryu Byung-Hyun Park Department of Physiology School of Oriental MedicineWonkwang UniversityIksan 570-749South Korea Department of Oral Anatomy School of DentistryChonbuk National UniversityJeonju 561-756JeonbukSouth Korea Department of Biochemistry Medical SchoolInstitute for Healthcare Technology DevelopmentMedical Research CenterChonbuk National UniversityJeonju 561-756JeonbukSouth Korea

AIM： To clarify the mechanism underlying the antidiabetic activities of cortex cinnamomi extract （CCE）. METHODS： To induce in vivo diabetes, mice were injected with streptozotocin （STZ） via a tail vein （100 mg STZ/kg body weight）. To determine the effects of CCE, mice were administered CCE twice daily for 7 d by oral gavage starting 1 wk before the STZ injection. Blood glucose and plasma insulin concentration were measured as an index of diabetes. Also, to induce cytotoxicity of RINm5F cells, we treated with cytokines （IL-1β （2.0 ng/mL） and IFN-γ （100 U/mL））. Cell viability and nitric oxide production were measured colorimetrically. Inducible nitric oxide synthase （iNOS） mRNA and protein expression were determined by RT-PCR and Western blotting, respectively. The activation of NF-κβ was assayed by using gel mobility shift assays of nuclear extracts. RESULTS： Treatment of mice with STZ resulted in hyperglycemia and hypoinsulinemia, which was further evidenced by immunohistochemical staining of islets. However, the diabetogenic effects of STZ were completely prevented when mice were pretreated with CCE. The inhibitory effect of CCE on STZ-induced hyperglycemia was mediated through the suppression of iNOS expression. In rat insulinoma RINm5F cells,CCE completely protected against interleukin-1β and interferon-y-mediated cytotoxicity. Moreover, RINm5F cells incubated with CCE showed significant reductions in interleukin-1β and interferon-y-induced nitric oxide production and in iNOS mRNA and protein expression, and these findings correlated well with in vivo observations. CONCLUSION： The molecular mechanism by which CCE inhibits iNOS gene expression appears to involve the inhibition of NF-κβ activation, These results reveal the possible therapeutic value of CCE for the prevention of diabetes mellitus progression,

关键词： Cortex cinnamomi Diabetes Streptozotocin Cytokine NF-κβ

来源：

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

Two-Dimensional Aerodynamic Models of Insect Flight for Robotic Flapping Wing Mechanisms of Maximum Efficiency

引用

Journal of Bionic Engineering 2008年第1期5卷 1-11页

作者： Thien-Tong Nguyen Doyoung Byun Department of Aeronautical Engineering Hochiminh City University of Technology Hochiminh City Vietnam Department of Aerospace Engineering Konkuk University Seoul 143-701 Korea

In the ＂modified quasi-steady＂ approach, two-dimensional （2D） aerodynamic models of flapping wing motions are analyzed with focus on different types of wing rotation and different positions of rotation axis to explain the force peak at the end of each half stroke. In this model, an additional velocity of the mid chord position due to rotation is superimposed on the translational relative velocity of air with respect to the wing. This modification produces augmented forces around the end of each stroke. For each case of the flapping wing motions with various combination of controlled translational and rotational velocities of the wing along inclined stroke planes with thin figure-of-eight trajectory, discussions focus on lift-drag evolution during one stroke cycle and efficiency of types of wing rotation. This ＂modified quasi-steady＂ approach provides a systematic analysis of various parameters and their effects on efficiency of flapping wing mechanism. Flapping mechanism with delayed rotation around quarter-chord axis is an efficient one and can be made simple by a passive rotation mechanism so that it can be useful for robotic application.

关键词： bionics modified quasi-steady approach insect flight hovering forward flight

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

Improvement in Background Error Covariances Using Ensemble Forecasts for Assimilation of High-Resolution Satellite Data

引用

Advances in Atmospheric Sciences 2011年第4期28卷 758-774页

作者： Seung-Woo LEE Dong-Kyou LEE School of Earth and Environmental Sciences Seoul National University

Satellite data obtained over synoptic data-sparse regions such as an ocean contribute toward improving the quality of the initial state of limited-area models. Background error covariances are crucial to the proper distribution of satellite-observed information in variational data assimilation. In the NMC （National Meteorological Center） method, background error covariances are underestimated over data-sparse regions such as an ocean because of small differences between different forecast times. Thus, it is necessary to reconstruct and tune the background error covariances so as to maximize the usefulness of the satellite data for the initial state of limited-area models, especially over an ocean where there is a lack of conventional data. In this study, we attempted to estimate background error covariances so as to provide adequate error statistics for data-sparse regions by using ensemble forecasts of optimal perturbations using bred vectors. The background error covariances estimated by the ensemble method reduced the overestimation of error amplitude obtained by the NMC method. By employing an appropriate horizontal length scale to exclude spurious correlations, the ensemble method produced better results than the NMC method in the assimilation of retrieved satellite data. Because the ensemble method distributes observed information over a limited local area, it would be more useful in the analysis of high-resolution satellite data. Accordingly, the performance of forecast models can be improved over the area where the satellite data are assimilated.

关键词： 3DVAR background error covariances retrieved satellite data assimilation ensemble forecasts.

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

Spatial Agglomeration of Exhibition Enterprises on a Regional Scale in China

引用

Chinese Geographical Science 2017年第3期27卷 497-506页

作者： FANG Zhongquan ZHANG Ying WANG Zhangjun ZHANG Lifeng College of Tourism Beijing Union University School of Management Jinan University

During the past two decades, the exhibition industry in China has been developing rapidly and has become an important part of the modern service industry, particularly the agglomeration characteristics of exhibition enterprises highlighted on the regional scale. Although the development of theoretical research on the western exhibition industry has taken place over time, the spatial perspective has not been at the centre of attention so far. This paper aims to fill this gap and report on the agglomeration characteristics of exhibition enterprises and their influential factors. Based on data about exhibition enterprises in the Pearl River Delta(PRD) during 1991–2013, using the Ripley K function analysis and kernel density estimation, this research identifies that: 1) the exhibition enterprise on the regional scale is significantly characterized by spatial agglomeration, and the agglomeration density and scale are continuously increasing; 2) the spatial pattern of agglomeration has developed from a single-center to multi-center form. Meanwhile, this paper profiles the factors influencing the spatial agglomeration of exhibition enterprises by selecting the panel data of nine cities in the PRD in 1999, 2002, 2006 and 2013. The results show that market capacity, urban informatization level and exhibition venues significantly influence the location choice of exhibition enterprises. Among them, the market capacity is a variable that exerts a far greater impact than other factors do.

关键词： exhibition enterprises spatial agglomeration Ripley K function analysis regional scale Pearl River Delta

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

Improved block matching approach to fast disparity estimation

引用

Journal of Systems Engineering and Electronics 2009年第6期20卷 1278-1285页

作者： Tao Tangfei Ja Choon Koo Hyouk Ryeol Choi School of Mechanical Engineering Xi'an Jiaotong Univ. Xi'an 710049 P. R. China State Key Lab. for Manufacturing Systems Engineering Xi'an 710049 P. R. China School of Mechanical Engineering Sungkyunkwan Univ. Suwon Republic of Korea

An improved block matching approach to fast disparity estimation in machine vision applications is proposed, where the matching criterion is the sum of the absolute difference（SAD）.By evaluating the lower bounds, which become increasingly tighter for the matching criteria, the method tries to successively terminate unnecessary computations of the matching criteria between the reference block in one image and the ineligible candidate blocks in another *** also eliminates the ineligible blocks as early as possible, while ensuring the optimal disparity of each ***, the proposed method can further speed up the elimination of ineligible candidate blocks by efficiently using the continuous constraint of disparity to predict the initial disparity of each *** performance of the new algorithm is evaluated by carrying out a theoretical analysis, and by comparing its performance with the disparity estimation method based on the standard block *** results demonstrate that the proposed algorithm achieves a computational cost reduction of over 50.5% in comparision with the standard block matching method.

关键词： machine vision block matching disparity estimation sum of the absolute difference.

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

Equilibrium Configurations of Lipid Bilayer Membranes and Carbon Nanostructures

引用

Communications in Theoretical Physics 2013年第2期59卷 213-228页

作者： Ivalo M. Mladenov Peter A. Djondjorov Mariana Ts. Hadzhilazova Vassil M. Vassilev Institute of Biophysics Bulgarian Academy of Sciences Acad. G. Bonchev Str. Block 21 1113 Sofia Bulgaria Institute of Mechanics Bulgarian Academy of Sciences Acad. G. Bonchev Str. Block 4 1113 Sofia Bulgaria

The present article concerns the continuum modelling of the mechanical behaviour and equilibrium shapes of two types of nano-scale objects： fluid lipid bilayer membranes and carbon nanostructures. A unified continuum model is used to handle four different ease studies. Two of them consist in representing in analytic form cylindrical and axisymmetric equilibrium configurations of single-wall carbon nanotubes and fluid lipid bilayer membranes subjected to uniform hydrostatic pressure. The third one is concerned with determination of possible shapes of junctions between a single-wall carbon nanotube and a fiat graphene sheet or another single-wall carbon nanotube. The last one deals with the mechanical behaviour of closed fluid lipid bilayer membranes （vesicles） adhering onto a fiat homogeneous rigid substrate subjected to micro-injection and uniform hydrostatic pressure.

关键词： fluid membranes graphene carbon nanotubes carbon nanostructures junctions variational statement Euler-Lagrange equations natural boundary conditions cell injection adhesion equi- librium shapes

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：