检索结果-南通市图书馆

Future Digital Design and Manufacturing: Embracing Industry 4.0 and Beyond

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2017年第5期30卷 1047-1049页

作者： Sheng-feng qin Kai Cheng School of Design Northumbria University College of Engineering Design and Physical SciencesBrunel University London

Digital design and manufacturing have been around for several decades from the numerical control of machine tools and automating engineering design in 1960s, through early Computer Aided Design （CAD）/Computer Aided Engineering analysis （CAE）/Computer Aided Manufacturing （CAM）, to modem digital design and manufacturing [1], and cloud manufacturing [2] converging into product lifecycle management （PLM） [3, 4] and Internet-enabled personalized manufacturing [5].

关键词： Digital design Future manufacturing Industry 4.0

Chemical constituents and biological activities of lycophytes and ferns

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Natural Medicines 2019年第12期17卷 887-891页

作者： ZHU qin-feng ZHAO qin-Shi State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of Botany Chinese Academy of Sciences

Lycophytes and ferns are unique and charismatic members of many terrestrial ecosystems and occupy the pivotal position in land plant origin and *** Chinese lycophytes and ferns flora,with approximately 2000 species,contributes a substantial component to the global lycophytes and ferns diversity,with estimates of 12000 *** them,about 433 species are medicinally recorded and researches based on their phytochemical properties are important topics in natural *** paper reviewed the research history and current status of chemical constituents and biological activities of lycophytes and ferns,which had highlighted the research progress of our group.

关键词： Lycophytes Ferns Chemical constituents Biological activities Lycopodium alkaloids

Crustal evolution of the Shiwandashan area in South China:Zircon U-Pb-Hf isotopic records from granulite enclaves in Indo-Sinian granites

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2010年第19期55卷 2028-2038页

作者： ZHAO Liang guo feng FAN WeiMing LI ChaoWen qin Xiaofeng LI HongXia Key Laboratory of Marginal Sea Geology Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Institute of Mineral Resources Chinese Academy of Geological Sciences Beijing 100037 China

标明日期的 U-Pb 在东南的 Guangxi 省从 Shiwandashan 区域在 Jiuzhou peraluminous 花岗石从 metasedimentary granulite 被外国领地包围的土地在锆石上结合了 Hf 同位素分析，华南在这份报纸被介绍。结果证明这些 granulite 被外国... 详细信息

标明日期的 U-Pb 在东南的 Guangxi 省从 Shiwandashan 区域在 Jiuzhou peraluminous 花岗石从 metasedimentary granulite 被外国领地包围的土地在锆石上结合了 Hf 同位素分析，华南在这份报纸被介绍。结果证明这些 granulite 被外国领地包围的土地的 protoliths 主要由有一座山峰的碎屑状的材料在 822 妈变老的 Neo-Mesoproterozoic (5641061 妈) 组成。这些材料可能从在 Rodinian Supercontinent 的 Neoproterozoic 决裂期间是 emplaced 的火的岩石被导出。辅助沉积包括 Paleoproterozoic (17782227 妈) ，有最旧的 U-Pb 的甚至 Meso-Paleoarchean 材料在 3551

关键词：锆石Hf同位素十万大山地区印支期花岗岩麻粒岩包体中国地区同位素记录 Pb 地壳演化

Design of a Servo Mechanical Press with Redundant Actuation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2009年第4期22卷 574-579页

作者： guo Weizhong GAO feng State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai 200240 China

A servo press is a new type of mechanical press that is driven by programmable motors and offers superior performance such as low noise, excellent efficiency and high precision for metal forming operations. Similar to multi-link mechanical presses, a servo mechanical press tends to grow in size as the tonnage increases that calls for larger, heavy duty servo motors, which could be expensive and may not even be available. In this paper, a new concept of servo mechanical press with redundant actuation is proposed firstly using two servo motors driving one input shaft, i.e. one-point-two-motor mode that makes it possible to produce a larger press with available servomotors. Then the punching mechanism design is detailed. The performance indices are set up including mechanical advantage reciprocal and link force ratios. A bounded feasible solution space is constructed for dimensional synthesis based on non-dimensional link lengths and assembly conditions. The performance atlases are depicted over the bounded feasible solution space that lead to a visual solution of the punching mechanism with global optimization. Finally, case studies are given to illustrate the design method with visual global optimization, and a prototype with 200 t punching force is being developed in our laboratory to demonstrate efficacy of the new concept for servo mechanical press. The presented research provides a feasible solution to the development of heavy-duty servo mechanical presses and finds potential applications in the development of other types of heavy equipments with electric drive.

关键词： servo mechanical press redundant actuation mechanism design visual global optimization prototype

Analysis for Multiple Cracks in 2D Piezoelectric Bimaterial Using the Singular Integral Equation Method

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2022年第2期35卷 261-272页

作者： Ting Cao Xiaobin feng Taiyan qin College of Engineering China Agricultural UniversityBeijing 100083China Department of CAE BYD Auto Industry Co.LtdShenzhen 518118China College of Science China Agricultural UniversityBeijing 100083China

A singular integral equation method is proposed to analyze the two-dimensional(2D)multiple cracks in anisotropic piezoelectric *** the Somigliana formula,a set of singular integral equations for the multiple crack problems are derived,in which the unknown functions are the derivatives of the generalized displacement discontinuities of the crack ***,the exact analytical solution of the extended singular stresses and extended stress intensity factors near the crack tip is *** integrals of the singular integral equations are computed by the Gauss-Chebyshev collocation ***,numerical solutions of the extended stress intensity factors of some examples are presented and discussed.

关键词： Piezoelectric bimaterial Boundary element method(BEM) Singular integral equation Stress intensity factor(SIF)

A language-independent neural network for event detection

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

Science China(Information Sciences) 2018年第9期61卷 81-92页

作者： Xiaocheng feng Bing qin Ting LIU Computer Science and Technology Harbin Institute of Technology

Event detection remains a challenge because of the difficulty of encoding the word semantics in various contexts. Previous approaches have heavily depended on language-specific knowledge and preexisting natural language processing tools. However, not all languages have such resources and tools available compared with English language. A more promising approach is to automatically learn effective features from data, without relying on language-specific resources. In this study, we develop a language-independent neural network to capture both sequence and chunk information from specific contexts and use them to train an event detector for multiple languages without any manually encoded features. Experiments show that our approach can achieve robust, efficient and accurate results for various languages. In the ACE 2005 English event detection task, our approach achieved a 73.4% F-score with an average of 3.0% absolute improvement compared with state-of-the-art. Additionally, our experimental results are competitive for Chinese and Spanish.

关键词： nature language processing event detection neural networks representation learning

CFD simulations for longwall gas drainage design optimisation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2017年第5期27卷 777-782页

作者： qin Johnny Qu qingdong guo Hua Coal Mining Research Program The Commonwealth Scientific and Industrial Research Organisation(CSIRO)Brisbane 883Australia

Computational fluid dynamics(CFD) simulation is an effective approach to develop and optimise gas drainage design for underground longwall coal mining. As part of the project supported by the Australian Government Coal Mining Abatement Technology Support Package(CMATSP), threedimensional CFD simulations were conducted to test and optimise a conceptual design which proposes using horizontal boreholes to replace vertical boreholes at an underground coal mine in *** performance between a vertical borehole and a horizontal borehole was first carried out to compare their capacity and effectiveness. Then a series of cases with different horizontal borehole designs were simulated to optimise borehole configuration parameters such as location, diameter, and number of boreholes. The study shows that the horizontal borehole is able to create low pressure sinks that protect the workings from goaf gas ingresses by changing goaf gas flow directions, and that it has the advantage to continuously maintain such low pressure sinks near the tailgate as the longwall advances. An example of optimising horizontal borehole locations in the longwall lateral direction is also given in this paper.

关键词： Goaf gas drainage Horizontal borehole CFD simulation Design optimisation Mining abatement technology

Distribution of static equilibrium points in static electric field produced by fixed electrons

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2014年第4期21卷 92-95页

作者： guo feng School of Science China University Mining & Technology(Beijing)

Fix n electrons on the disk ｜z｜≤R. They generate a static electric field. Let a be an electron located in the disk ｜z｜≤R sin π/n. It shows that the closed disk with center a and radius R contains at least one s... 详细信息

关键词： fixed electrons static electric field static equilibrium points

Fault Diagnosis Model Based on Feature Compression with Orthogonal Locality Preserving Projection

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2011年第5期24卷 891-898页

作者： TANG Baoping LI feng qin Yi State Key Laboratory of Mechanical Transmission Chongqing University Chongqing 400030 China

Based on feature compression with orthogonal locality preserving projection（OLPP）,a novel fault diagnosis model is proposed in this paper to achieve automation and high-precision of fault diagnosis of rotating *** this model,the original vibration signals of training and test samples are first decomposed through the empirical mode decomposition（EMD）,and Shannon entropy is constructed to achieve high-dimensional *** order to replace the traditional feature extraction way which does the selection manually,OLPP is introduced to automatically compress the high-dimensional eigenvectors of training and test samples into the low-dimensional eigenvectors which have better *** that,the low-dimensional eigenvectors of training samples are input into Morlet wavelet support vector machine（MWSVM） and a trained MWSVM is ***,the low-dimensional eigenvectors of test samples are input into the trained MWSVM to carry out fault *** evaluate our proposed model,the experiment of fault diagnosis of deep groove ball bearings is made,and the experiment results indicate that the recognition accuracy rate of the proposed diagnosis model for outer race crack、inner race crack and ball crack is more than 90%.Compared to the existing approaches,the proposed diagnosis model combines the strengths of EMD in fault feature extraction,OLPP in feature compression and MWSVM in pattern recognition,and realizes the automation and high-precision of fault diagnosis.

关键词： orthogonal locality preserving projection(OLPP) manifold learning feature compression Morlet wavelet support vector machine(MWSVM) empirical mode decomposition(EMD) fault diagnosis