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Properties of (Fe-B)-doped Sn-1.0Ag-0.5Cu solders prepared by mechanical alloying

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Rare Metals 2019年第7期38卷 665-674页

作者： ruo-Da wang Qiang Hu Shao-Ming Zhang Fu-Wen Zhang Cai-Tao Lu Zhi-Gang wang General Research Institute for Nonferrous Metals Beijing 100088 China Beijing COMPO Advanced Technology Co. Ltd. Beijing 101407 China

To introduce boron (B) into the Sn-1.0Ag-0.5Cu (SAC 105) solder, based on the thermodynamic calculations, iron (Fe) is a competent carrier component for bonding B and Sn. The Sn-Fe-B master alloys were prepared by mechanical alloying initially;then, the SAC 105- 0.05(Fe-B) and SAC 105-0.1 (Fe-B) solder alloys were prepared using 72-h-milling Sn-Fe-B master alloys. The preparation process and the properties of solders were studied in this work. For the Sn-Fe-B master alloys, the results show that with the increase in the ball-milling time, the powder changes illustrate a cold welding-crushingcold welding cyclic process. Moreover, the supersaturated solid solubility of (Fe-B) increases gradually in the alloys, matrix and the lattice distortion increases to 0.167% after 72-h milling. Meanwhile, the alloying degree is increasingly apparent, and after 72-h milling, the content of B in the Sn matrix reaches 2.38 wt%. For the solder alloys, with the (Fe-B) content in creasing, the melting point decreases and a significant grain refinement occurs in the matrix. Compared to the benchmark SAC105, the hardness of SAC105-0.05(Fe-B) and SAC 105-0.1 (Fe-B) solder alloys prepared by this method is improved by 20.65% and 34.79%, respectively. The present research provides a novel approach for introducing the immiscible component into the lead-free solder alloys.

关键词： Sn-1.0Ag-0.5Cu Sn-Fe-B Mechanical alloying Supersaturated solid solution

A mathematical model of cortical bone remodeling at cellular level under mechanical stimulus

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Acta Mechanica Sinica 2012年第6期28卷 1678-1692页

作者： qing-Hua Qin Ya-Nan wang Research School of Engineering The Australian National University

A bone cell population dynamics model for cor- tical bone remodeling under mechanical stimulus is devel- oped in this paper. The external experiments extracted from the literature which have not been used in the creation of the model are used to test the validity of the model. Not only can the model compare reasonably well with these ex- perimental results such as the increase percentage of final values of bone mineral content （BMC） and bone fracture en- ergy （BFE） among different loading schemes （which proves the validity of the model）, but also predict the realtime devel- opment pattern of BMC and BFE, as well as the dynamics of osteoblasts （OBA）, osteoclasts （OCA）, nitric oxide （NO） and prostaglandin E2 （PGE2） for each loading scheme, which can hardly be monitored through experiment. In conclusion, the model is the first of its kind that is able to provide an in- sight into the quantitative mechanism of bone remodeling at cellular level by which bone cells are activated by mechan- ical stimulus in order to start resorption/formation of bone mass. More importantly, this model has laid a solid foun- dation based on which future work such as systemic control theory analysis of bone remodeling under mechanical stimu- lus can be investigated. The to-be identified control mecha- nism will help to develop effective drugs and combined non- pharmacological therapies to combat bone loss pathologies. Also this deeper understanding of how mechanical forces quantitatively interact with skeletal tissue is essential for the generation of bone tissue for tissue replacement purposes in tissue engineering.

关键词： Cortical bone remodeling Cell population dy-namics Mechanotransduction Mechanosensitivity Bonefracture energy - Bone mineral content

New family of piecewise smooth support vector machine

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Journal of Systems Engineering and Electronics 2015年第3期26卷 618-625页

作者： qing Wu Leyou Zhang Wan wang School of Automation Xi'an University of Posts and Telecommunications School of Mathematics and Statistics Xidian University School of Computer Science and Technology Xi'an University of Posts and Telecommunications

Support vector machines （SVMs） have been extensively studied and have shown remarkable success in many applications. A new family of twice continuously differentiable piecewise smooth functions are used to smooth the objective function of uncon- strained SVMs. The three-order piecewise smooth support vector machine （TPWSSVMd） is proposed. The piecewise functions can get higher and higher approximation accuracy as required with the increase of parameter d. The global convergence proof of TPWSSVMd is given with the rough set theory. TPWSSVMd can efficiently handle large scale and high dimensional problems. Nu- merical results demonstrate TPWSSVMa has better classification performance and learning efficiency than other competitive base- lines.

关键词： support vector machine (SVM) piecewise smooth function smooth technique bound of convergence.

A systematic method of smooth switching LPV controllers design for a morphing aircraft

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Chinese Journal of Aeronautics 2015年第6期28卷 1640-1649页

作者： Jiang Weilai Dong Chaoyang wang qing School of Aeronautic Science and Engineering Beihang University School of Automation Science and Electrical Engineering Beihang University

This paper is concerned with a systematic method of smooth switching linear parameter- varying （LPV） controllers design for a morphing aircraft with a variable wing sweep angle. The morphing aircraft is modeled as an LPV system, whose scheduling parameter is the variation rate of the wing sweep angle. By dividing the scheduling parameter set into subsets with overlaps, output feedback controllers which consider smooth switching are designed and the controllers in over- lapped subsets are interpolated from two adjacent subsets. A switching law without constraint on the average dwell time is obtained which makes the conclusion less conservative. Furthermore, a systematic algorithm is developed to improve the efficiency of the controllers design process. The parameter set is divided into the fewest subsets on the premise that the closed-loop system has a desired performance. Simulation results demonstrate the effectiveness of this approach.

关键词： Morphing aircraft Parameter set division:Robust control Smooth switching Switched linear parameter-varying system

Effects of information transmission delay and channel blocking on synchronization in scale-free Hodgkin-Huxley neuronal networks

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Acta Mechanica Sinica 2011年第6期27卷 1052-1058页

作者： qing-Yun wang Yan-Hong Zheng Department of Dynamics and Control Beihang University 100191 Beijing China School of Mathematics and Computer Science Fujian Normal University 350007 Fuzhou China

In this paper,we investigate the evolution of spatiotemporal patterns and synchronization transitions in dependence on the information transmission delay and ion channel blocking in scale-free neuronal *** the underlying model of neuronal dynamics,we use the Hodgkin-Huxley equations incorporating channel blocking and intrinsic *** is shown that delays play a significant yet subtle role in shaping the dynamics of neuronal *** particular,regions of irregular and regular propagating excitatory fronts related to the synchronization transitions appear intermittently as the delay ***,the fraction of working sodium and potassium ion channels can also have a significant impact on the spatiotemporal dynamics of neuronal *** the fraction of blocked sodium channels increases,the frequency of excitatory events decreases,which in turn manifests as an increase in the neuronal synchrony that,however,is dysfunctional due to the virtual absence of large-amplitude ***,we also show that larger coupling strengths improve synchronization irrespective of the information transmission delay and channel *** presented results are also robust against the variation of the network size,thus providing insights that could facilitate understanding of the joint impact of ion channel blocking and information transmission delay on the spatiotemporal dynamics of neuronal networks.

关键词： Scale-free neuronal networks - Information transmission delay Ion channel blocking Synchronization

Unsteady aerodynamic modeling at high angles of attack using support vector machines

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Chinese Journal of Aeronautics 2015年第3期28卷 659-668页

作者： wang qing Qian Weiqi He Kaifeng State Key Laboratory of Aerodynamics Computational Aerodynamics Institute China Aerodynamics Research and Development Center

Abstract Accurate aerodynamic models are the basis of flight simulation and control law design. Mathematically modeling unsteady aerodynamics at high angles of attack bears great difficulties in model structure determination and parameter estimation due to little understanding of the flow mechanism. Support vector machines （SVMs） based on statistical learning theory provide a novel tool for nonlinear system modeling. The work presented here examines the feasibility of applying SVMs to high angle.-of-attack unsteady aerodynamic modeling field. Mainly, after a review of SVMs, several issues associated with unsteady aerodynamic modeling by use of SVMs are discussed in detail, such as sele, ction of input variables, selection of output variables and determination of SVM parameters. The least squares SVM （LS-SVM） models are set up from certain dynamic wind tunnel test data of a delta wing and an aircraft configuration, and then used to predict the aerodynamic responses in other tests. The predictions are in good agreement with the test data, which indicates the satisfving learning and generalization performance of LS-SVMs.

关键词： Aerodynamic modeling High angle of attack Support vector machines(SVMs) Unsteady aerodynamics Wind tunnel test

MUTS-Based Cooperative Target Stalking for A Multi-USV System

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IEEE/CAA Journal of Automatica Sinica 2023年第7期10卷 1582-1592页

作者： Chengcheng wang Yulong wang qing-Long Han Yunkai Wu Shanghai Key Laboratory of Power Station Automation Technology and the School of Mechatronic Engineering and AutomationShanghai UniversityShanghai 200444China School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyMelbourne VIC 3122Australia College of Automation Jiangsu University of Science and TechnologyZhenjiang 212100China

This paper is concerned with the cooperative target stalking for a multi-unmanned surface vehicle(multi-USV)*** on the multi-agent deep deterministic policy gradient(MADDPG)algorithm,a multi-USV target stalking(MUTS)algorithm is ***,a V-type probabilistic data extraction method is proposed for the first time to overcome shortcomings of the MADDPG *** advantages of the proposed method are twofold:1)it can reduce the amount of data and shorten training time;2)it can filter out more important data in the experience buffer for ***,in order to avoid the collisions of USVs during the stalking process,an action constraint method called Safe DDPG is ***,the MUTS algorithm and some existing algorithms are compared in cooperative target stalking *** order to demonstrate the effectiveness of the proposed MUTS algorithm in stalking tasks,mission operating scenarios and reward functions are well designed in this *** proposed MUTS algorithm can help the multi-USV system avoid internal collisions during the mission ***,compared with some existing algorithms,the newly proposed one can provide a higher convergence speed and a narrower convergence domain.

关键词： Cooperative target stalking improved deep reinforcement learning multi-unmanned surface vehicle(multi-USV)systems V-type probabilistic data extraction

Challenges and strategies in progress of drug delivery system for traditional Chinese medicine Salviae Miltiorrhizae Radix et Rhizoma(Danshen)

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Chinese Herbal Medicines 2021年第1期13卷 78-89页

作者： ruo-ning wang Hua-cong Zhao Jian-yu Huang Hong-lan wang Jun-song Li Yin Lu Liu-qing Di School of Pharmacy Nanjing University of Chinese MedicineNanjing 210046China Jiangsu Engineering Research Center for Efficient Delivery System of TCM Nanjing 210046China Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica Nanjing 210046China

Traditional Chinese medicines(TCMs), with a history of thousands of years, are widely used clinically with effective treatment. However, the drug delivery systems(DDSs) for TCMs remains major challenges due to the characteristics of multi-components including alkaloids, flavones, anthraquinones, glycosides,proteins, volatile oils and other types. Therefore, the novel preparations and technology of modern pharmaceutics is introduced to improve TCM therapeutic effects due to instability and low bioavailability of active ingredients. Salviae Miltiorrhizae Radix et Rhizoma, the radix and rhizomes of Salvia miltiorrhiza Bunge(Danshen in Chinese), is a well known Chinese herbal medicine for protecting the cardiovascular system, with active ingredients mainly including lipophilic tanshinones and hydrophilic salvianolic *** this review, this drug is taken as an example to present challenges and strategies in progress of DDSs for TCMs. This review would also summary the characteristics of active ingredients in it including physicochemical properties and pharmacological effects. The purpose of this review is to provide inspirations and ideas for the DDSs designed from TCMs by summarizing the advances on DDSs for both singleand multi-component from Danshen.

关键词： active ingredients challenges and strategies drug delivery systems Salvia miltiorrhiza Bunge Salviae Miltiorrhizae Radix et Rhizoma traditional Chinese medicines

Optimal Design for a Retrial Queueing System with State-Dependent Service Rate

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Journal of Systems Science & Complexity 2017年第4期30卷 883-900页

作者： ZHANG Xuelu wang Jinting MA qing Department of Mathematics Beijing Jiaotong University School of Science Qilu University of Technology Department of Basic Courses Shandong Women’s University

This paper considers a single server retrial queue in which a state-dependent service policy is adopted to control the service rate. Customers arrive in the system according to a Poisson process and the service times and inter-retrial times are all exponentially distributed. If the number of customers in orbit is equal to or less than a certain threshold, the service rate is set in a low value and it also can be switched to a high value once this number exceeds the threshold. The stationary distribution and two performance measures are obtained through the partial generating functions. It is shown that this state-dependent service policy degenerates into a classic retrial queueing system without control policy under some conditions. In order to achieve the social optimal strategies, a new reward-cost function is established and the global numerical solutions, obtained by Canonical Particle Swarm Optimization algorithm, demonstrate that the managers can get more benefits if applying this state-dependent service policy compared with the classic model.

关键词： Particle swarm optimization algorithm retrial queues social optimal strategy statedependent service policy