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Effects of Vertical Angle of Conical Punch on Stretch Flangeability of High Strength Steel

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Acta Metallurgica Sinica(English Letters) 2015年第12期28卷 1503-1509页

作者： Yasuhiro Ito Yoshiaki Nakazawa Yukihisa Kuriyama Katsuyuki Suzuk Noriyuki Suzuki Nippon Steel and Sumitomo Metal corporation The University of Tokyo

To clarify the effects of the vertical angle of a conical punch on stretch flangeability, hole expansion forming tests were conducted. Test results showed that the hole expansion ratio becomes larger as the vertical angle *** also showed that the fracture strain at the fracture location on the hole edge was constant and independent of the vertical angle. This is because the hole expansion ratio was controlled not only by the fracture strain, which is independent of the vertical angle, but also by deformation uniformity along the hole edge. From the result of numerical analyses, it was determined that deformation uniformity depends on the gradient of circumferential stress along the radius direction. When the vertical angle is sharp, the circumferential stress showed a steep decline and the deformation localization was suppressed. Consequently, the hole edge deformed more uniformly and the hole expansion ratio became larger. It is concluded that in order to improve stretch flangeability of high strength steel, it is important to uniformly deform the hole edge by applying a conical punch with a sharp vertical angle.

关键词： Formability Ductile fracture Finite element analysis Hole expansion test

Control Strategy Optimization of Voltage Source Converter Connected to Various Types of AC Systems

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Journal of Modern Power Systems and Clean Energy 2021年第1期9卷 77-84页

作者： Zehong Liu Senior Member Xianshan Guo State Grid corporation of China Beijing 100031China

Connecting the voltage source converters(VSCs) to various types of AC systems results in different operation characteristics and core problems associated with traditional control strategies. Therefore, it is necessary to optimize the control strategies of the VSCs according to the types of AC *** the VSCs connected to islanded renewable power plants, a voltage/frequency(V/f) droop control strategy is proposed to damp fluctuations of AC voltage and frequency in the island,which is vital for bipolar VSC control. In addition, a multibranch impedance equivalent method for renewable power plants is proposed, with which large-scale renewable power plants can be modeled accurately in the frequency domain to prevent wide-band oscillation. For the VSCs connected to strong AC systems, smart AC voltage and coordinated frequency transient control strategies are proposed, which can improve AC system transient stability. For the VSCs connected to weak AC systems, the relationship between the system stability and strength is analyzed, and then the control strategy of inner-loop control parameter optimization and outer-loop power limiting(if necessary) is proposed to improve the stability of the allied system. The proposed strategies are verified by both software simulation and field commissioning.

关键词： Control strategy optimization islanded renewable power plants stability voltage source converter(VSC) AC system

Development and evaluation of corrosion resistant coating for expandable rock bolt against highly corrosive ground conditions

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International Journal of Mining Science and Technology 2018年第1期28卷 145-151页

作者： Kevin Jinrong Ma John Stankus Dakota Faulkner Keystone Mining Services LLC of Jennmar Corporation Inc

Expandable rock bolts are widely used in hard rock mines as an efficient ground control ***, capacity and service life can be significantly reduced if the metallic body is subjected to *** some hard rock mines in the U.S., highly corrosive ground conditions exist, and it has been reported that inflatable rock bolts have corroded within a few months after *** provide mining industry a cost-effective inflatable bolt and combat the corrosion issues, Jennmar corporation, Inc.,and its subsidiary Keystone Mining Services, LLC(KMS), analyzed corroded bolt samples, identified root causes, evaluated properties of various coating materials, and developed a new inflatable rock bolt,Python M3^(TM), that is protected with an innovative PyFlexU2^(TM)*** new generation Python M3^(TM) features improved steel chemistry for reliable performance, modified profile for better inflation, and surface preparation and coating *** PyFlexU2^(TM)is impervious to liquid and air, durable, and UV *** a flexible, adhesive, and highly corrosion-resistant undercoating, and a very hard sacrificial surface coating, the PyFlexU2^(TM)coating system provides the Python M3^(TM)superior protection against chemical corrosion and physical scratch *** under-coating has exceptional flexibility and adhesion to prevent coating micro-cracks or fractures after bolt inflation and possesses excellent corrosion resistance to acids(pH 11), fuels, and salt *** corrosion and scratch resistant PyFlexU2^(TM)coating offers very effective bolt protection for extra longevity in highly corrosive *** Python M3^(TM)coated with PyFlexU2^(TM)has been tested in the most challenging conditions,including laboratory corrosion tests in extreme acidic and basic solvents, rock slurry, and borehole scratch insertion *** demonstrated corrosion and scratch resistance, the product has been greatly welcomed by hard rock min

关键词： Rock bolt Hard rock Corrosive ground condition Bolt corrosion

General Torsional Stiffness Matching of Off-road Vehicle

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Chinese Journal of Mechanical Engineering 2009年第3期22卷 331-335页

作者： HUANG Song Dongfeng Motor corporation Wuhan 430056 China

Increasing frame torsional stiffness of off-road vehicle will lead to the decrease of body torsional deformation, but the increase of torsional loads of frame and suspension system and the decrease of wheel adhesive weight. In severe case, a certain wheel will be out of contact with road surface. Appropriate matching of body, frame and suspension torsional stiffnesses is a difficult problem for off-road vehicle design. In this paper, these theoretically analytic models of the entire vehicle, body, frame and suspension torsional stiffness are constructed based on the geometry and mechanism of a light off-road vehicle＇s body, frame and suspension. The body and frame torsional stiffnesses can be calculated by applying body CAE method, meanwhile the suspension＇s rolling angle stiffness can be obtained by the bench test of the suspension＇s elastic elements. Through fixing the entire vehicle, using sole timber to raise wheels to simulate the road impact on a certain wheel, the entire vehicle torsional stiffness can be calculated on the geometric relation and loads of testing. Finally some appropriate matching principles of the body, frame and suspension torsional stiffness are summarized according to the test and analysis results. The conclusion can reveal the significance of the suspension torsional stiffness on off-road vehicle＇s torsion-absorbing capability. The results could serve as a reference for the design of other off-road vehicles.

关键词： off-road vehicle bodywork frame suspension system torsional stiffness matching

Reputation-Based Collaborative Spectrum Sensing Scheme in Cognitive Radio Networks

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Journal of Shanghai Jiaotong university(Science) 2011年第6期16卷 641-647页

作者：赵士康何迪李文化朱伏生 Department of Electronic Engineering Shanghai Jiaotong University ARCON corporation Zhongxing Telecommunication Equipment corporation

Collaborative spectrum sensing is proposed to improve the detection performance in cognitive radio (CR) networks. However, most of the current collaborative sensing schemes are vulnerable to the interference of the malicious secondary users (SUs). In this paper we propose a reputation-based collaborative spectrum sensing scheme to improve the security of cooperative sensing by mitigating the impacts of misbehaviors. The fusion center calculates the reputation rating of each SU according to their history reports to weight their sensing results in the proposed scheme. We analyze and evaluate the performance of the proposed scheme and its advantages over previous schemes in expansibility and integrity. Simulation results show that the proposed scheme can minimize the harmful influence from malicious SUs.

关键词： cognitive radio (CR) collaborative spectrum sensing reputation-based scheme security

Intent-Slot Correlation Modeling for Joint Intent Prediction and Slot Filling

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Journal of Computer Science & Technology 2022年第2期37卷 309-319页

作者： Jun-Feng Fan Mei-Ling Wang Chang-Liang Li Zi-Qiang Zhu Lu Mao AI Laboratory KingSoft CorporationBeijing 100190China

Slot filling and intent prediction are basic tasks in capturing semantic frame of human *** and intent have strong correlation for semantic frame *** each utterance,a specific intent type is generally determined with the indication information of words having slot tags(called as slot words),and in reverse the intent type decides that words of certain categories should be used to fill as ***,the Intent-Slot correlation is rarely modeled explicitly in existing studies,and hence may be not fully *** this paper,we model Intent-Slot correlation explicitly and propose a new framework for joint intent prediction and slot ***,we explore the effects of slot words on intent by differentiating them from the other words,and we recognize slot words by solving a sequence labeling task with the bi-directional long short-term memory(BiLSTM)***,slot recognition information is introduced into attention-based intent prediction and slot filling to improve semantic *** addition,we integrate the Slot-Gated mechanism into slot filling to model dependency of slots on ***,we obtain slot recognition,intent prediction and slot filling by training with joint *** results on the benchmark Air-line Travel Information System(ATIS)and Snips datasets show that our Intent-Slot correlation model achieves state-of-the-art semantic frame performance with a lightweight structure.

关键词： spoken language understanding slot filling intent prediction Intent-Slot correlation slot recognition

Architecture,Key Technologies and Applications of Load Dispatching in China Power Grid

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Journal of Modern Power Systems and Clean Energy 2022年第2期10卷 316-327页

作者： Yu Dong Xin Shan Yaqin Yan Xiwu Leng Yi Wang State Grid corporation of China Beijing 100031China NARI Group corporation(State Grid Electric Power Research Institute) Nanjing 211000China

With the development of renewable energy and the changes in the characteristics of power grid,it is becoming increasingly difficult to balance power supply and demand in space and *** addition,the requirement for improved dispatching capability of power grid is ***,the potential of flexible load dispatching should be realized,which can promote the large-scale consumption of renewable energy and the construction of new power *** on the analysis of existing load dispatching studies and the differences in the characteristics of domestic and foreign load dispatchings,a technical architecture and several key technologies are proposed for load resources to participate in power grid dispatching under the new situation,i.e.,the autonomous collaborative control system of load *** system implements the multi-layer coordinated control of main,distribution and micro grids(load aggregators).Adjustable load resources are aggregated through an aggregator operation platform and connected with a dispatcher load regulator platform to realize real-time data interaction with dispatching agencies as well as the monitoring,con-trol,and marketing of *** supports the load resources to participate in network-wide dispatching optimization via continuous power *** key technologies such as the control mode,load modeling,dispatching strategy,and safety protection are also *** the closed-loop control of orderly charging piles and energy storage clusters in the North China Power Grid,the feasibility of the proposed architecture and key technologies is *** route has successively supported multiple adjustable load aggregators to partici-pate in the ancillary services market of North China Power Grid for ***,the technical challenges of load resources participating in power grid dispatching under the dual carbon goals are discussed and prospected.

关键词： Automatic power control(APC) load modeling load dispatching renewable energy accommodation situation awareness.

Making aviation green

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Advances in Manufacturing 2013年第1期1卷 42-49,43-49页

作者： Zuo-Ming Lin Aviation Industry corporation of China

With rapid economic progress and tremendous advances of science and technology, awareness of environmental protection has become worldwide consensus. Saving energy, reducing emission and dealing with climate changes are global objectives. The aviation industry belongs to the manufacturing industry. Air transportation is a major con- sumer of natural resources and energy. Development of green technology in aviation manufacturing will have sig- nificant impacts on air transportation. On the basis of the international situation, this article focuses on the current development of green aviation manufacturing in China, depicting AVIC＇ s objectives and commitments to achieving this.

关键词： Green aviation Low carbon manufacturingEnergy saving Emission reduction

Efficiency of Model Induction Motor Using Various Non-Oriented Electrical Steels

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Journal of Materials Science & Technology 2000年第2期16卷 238-243页

作者： Atsuhito Honda, Masaki Kawano, Masyoshi Ishida, Kejji Sato and Michiro Komatsubara (Kawasaki Steel corporation, Kurashiki 712-8511, Japan) Isamu Ohyama (Kawasaki Steel Techno-Research corporation, Chiba 260-0835, Japan) Kawasaki Steel corporation Kurashiki 712-8511 Japan Kawasaki Steel Techno-Research corporation Chiba 260-0835 Japan

The performance of a 3-phase 6-pole 400 W inverter-drive induction motor was investigated using a variety of non-oriented electrical steels for stator core at PWM inverter fundamental wave frequencies of 30 to 300 Hz. There existed an optimum Si content of the material depending on the tooth flux density. Both reduction of material thickness and stress-relief annealing of the stator core improved the motor efficiency. The influence of Si content on the efficiency was small at lower PWM frequencies, while at higher frequencies the motor efficiency increased with increasing Si content. The Cu loss WC increased and the Fe loss Wi counteractiveiy decreasedwith increasing Si content at lower frequencies; while at higher frequencies Wi had dominant effect on the efficiency. Newly developed materials RMA, having lower Fe losses after stress-relief annealing and higher flux densities with lower Si contents, showed motor efficiencies superior to conventional J1S grade materials with comparable Fe losses.

关键词： In Efficiency of Model Induction Motor Using Various Non-Oriented Electrical Steels RMA Figure St high