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The contracting and unshearing motion of flare loops in the X 7.1 flare on 2005 January 20 during its rising phase

Research in Astronomy and Astrophysics 2013年第5期13卷 526-536页

作者： Tuan-Hui Zhou Jun-Feng Wang Dong Li Qi-Wu Song Victor Melnikov Hai-Sheng Ji Key Laboratory for Dark Matter and Space Science Purple Mountain Observatory Chinese Academy of Sciences Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences Purple Mountain Observatory Chinese Academy of Sciences School of Physics Optoelectronic engineering Nanjing University of Information Science and Technology Graduate University of Chinese academy of Sciences

With the aim of studying the relationship between the relative motions of the loop-top （LT） source and footpoints （FPs） during the rising phase of solar flares, we give a detailed analysis of the X7.1 class flare that occurred on 2005 January 20. The flare was clearly observed by RHESSI, showing a distinct X-ray flaring loop with a bright LT source and two well-defined hard X-ray （HXR） FPs. In particular, we correct the projection effect for the positions of the FPs and magnetic polarity inversion line. We find that：（1） The LT source showed an obvious U-shaped trajectory. The source of the higher energy LT shows a faster downward/upward speed. （2） The evolution of FPs was temporally correlated with that of the LT source. The converging/separating motion of FPs corresponds to the downward/upward motion of the LT source. （3） The initial flare shear of this event is found to be nearly 50 degrees, and it has a fluctuating decrease throughout the contraction phase as well as the expansion phase. （4） Four peaks of the time profile of the unshearing rate are found to be temporally correlated with peaks in the HXR emission flux. This flare supports the overall contraction pic- ture of flares： a descending motion of the LT source, in addition to converging and unshearing motion of FPs. All results indicate that the magnetic field was very highly sheared before the onset of the flare.

关键词： Sun: activity -- Sun: magnetic fields -- Sun: flares

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Observer-based Adaptive Optimal Control for Unknown Singularly Perturbed Nonlinear Systems With Input Constraints

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IEEE/CAA Journal of Automatica Sinica 2017年第1期4卷 48-57页

作者： Zhijun Fu Wenfang Xie Subhash Rakheja Jing Na College of Mechanical engineering Zhejiang University of Technology Department of Mechanical & Industrial engineering Concordia University Faculty of Mechanical & Electrical engineering Kunming University of Science & Technology

This paper introduces an observer-based adaptive optimal control method for unknown singularly perturbed nonlinear systems with input constraints. First, a multi-Time scales dynamic neural network MTSDNN observer with a novel updating law derived from a properly designed Lyapunov function is proposed to estimate the system states. Then, an adaptive learning rule driven by the critic NN weight error is presented for the critic NN, which is used to approximate the optimal cost function. Finally, the optimal control action is calculated by online solving the Hamilton-Jacobi-Bellman HJB equation associated with the MTSDNN observer and critic NN. The stability of the overall closed-loop system consisting of the MTSDNN observer, the critic NN and the optimal control action is proved. The proposed observer-based optimal control approach has an essential advantage that the system dynamics are not needed for implementation, and only the measured input U+002F output data is needed. Moreover, the proposed optimal control design takes the input constraints into consideration and thus can overcome the restriction of actuator saturation. Simulation results are presented to confirm the validity of the investigated approach. © 2014 Chinese Association of Automation.

关键词： Closed loop systems Cost functions Lyapunov functions Neural networks Nonlinear systems Optimal control systems Perturbation techniques

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Characterization of the triple-gate flash memory endurance degradation mechanism

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Journal of Semiconductors 2009年第1期30卷 19-22页

作者：曹子贵孙凌李嘉秩 Shanghai Institute of Microsystem and Information technology Chinese Academy of Sciences Graduate University of the Chinese academy of Sciences Grace Semiconductor Manufacturing Corporation

Write/erase degradation after endurance cycling due to electron trapping events in triple-gate flash memory have been detected and analyzed using a UV erasure method. Different from the commonly degradation phenomenon, write-induced electron trapping in the floating gate oxide, electron trapping in tunneling oxide is observed in triple-gate flash memory. Further, the degradation due to single-electron locally trapping/de-trapping in hornshaped SuperFlash does not occur in the triple-gate flash cell This is because of planar poly-to-poly erasing in the triple-gate flash cell instead of tip erasing in the horn-shaped SuperFlash cell Moreover, by TCAD simulation, the trap location is identified and the magnitude of its density is quantified roughly.

关键词： Fowler-Nordheim tunneling endurance traps UV erasure

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Pulse radiolysis and laser flash photolysis study of balofloxacin

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Nuclear Science and Techniques 2013年第B12期24卷 67-72页

作者： XU Yulie LIU Yancheng LI Haixia ZHANG Peng TANG Ruizhi CAO Xiyan WANG Wenfeng Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China Graduate University of Chinese academy of Science Beijing 100049 China School of Chemistry and Chemical engineering Hunan University of Science and Technology Xiangtan 411201 China

Pulse radiolysis studies of the reactions between balofloxacin (BFX) and e(aq)(-), hydroxyl radical ((OH)-O-.), and N-3(.) were carried out to investigate the photosensitive toxicity of BFX. The BFX radical anion formed in the reaction of BFX with e(aq)(-) was located at 380 nm. The transient species formed in the reaction of BFX with (OH)-O-. radical were located in the region of 370 rim to 580 rim, with a maximum lambda(max) at 390 rim. The BFX radical cation was obtained by reacting BFX with N-3(.), and showed an absorption band at around 365 nm. The UV-Vis absorption of the BFX was found to be clearly dependent on pH. The pK(a) value of BFX was estimated to be 6.0 +/- 0.2. Under neutral conditions, the rate constants of BFX reacting with N-3(.) and e(aq)(-) were determined to be 1.3x10(10) dm(3.)mol(-1).s(-1) and 1.4x10(10) dm(3).mol(-1.)s(-1), respectively.

关键词：巴洛沙星脉冲辐解激光光解阴离子自由基阳离子自由基 UV-Vis 羟基自由基 OH自由基

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Field testing of shear strength of granite residual soils

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Journal of Rock Mechanics and Geotechnical engineering 2024年第9期16卷 3718-3732页

作者： Song Yin Pengfei Liu Xianwei Zhang Wenyuan He Pan Yan Yuzhou Sun School of Civil engineering and Architecture Zhongyuan University of TechnologyZhengzhou450007China State Key Laboratory of Geomechanics and Geotechnical engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

The characteristics of residual soils are very different from those of sedimentary *** the strength characteristics of sedimentary soils have been studied extensively,the shear strength characteristics of granitic residual soils(GRS)subjected to the weathering of parent rocks have rarely been *** this study,the shear strength characteristics of GRS in the Taishan area of southeast China(TSGRS)were studied by field and laboratory *** field tests consisted of a cone penetration test(CPT),borehole shear test(BST),self-boring pressuremeter test(SBPT),and seismic dilatometer Marchetti test(SDMT).The shortcomings of laboratory testing are obvious,with potential disturbances arising through the sampling,transportation,and preparation of soil *** to the special structure of GRS samples and the ease of disturbance,the results obtained from laboratory tests were generally lower than those obtained from situ *** CPT and scanning electron microscopy(SEM)results indicated significant weathering and crustal hardening in the shallow *** resulted in significant differences in the strength and strength parameters of shallow soil obtained by the *** on the SDMT and SBPT results,a comprehensive evaluation method of shear strength for TSGRS was *** SBPT was suitable for evaluating the strength of shallow *** material index(ID)and horizontal stress index(KD)values obtained by the SDMT satisfied the empirical relationship proposed by Marchetti based on the ID index,and were therefore considered suitable for the evaluation of the shear strength of deep GRS.

关键词： Granite residual soils Shear strength Field tests Self-boring pressuremeter Seismic dilatometer Borehole shear test

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Dithiol treatments enhancing the efficiency of hybrid solar cells based on PTB7 and CdSe nanorods

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Nano Research 2015年第9期8卷 3045-3053页

作者： Weining Luo Tonggang Jiu Chaoyang Kuang Bairu Li Fushen Lu Junfeng Fang Institute of New Energy technology Ningbo Institute of Material Technology and Engineering (NIMTE) Chinese Academy of Sciences (CAS) Ningbo 315201 China Department of Chemistry College of Science Shantou University Shantou 515063 China

We report the fabrication of polymer/inorganic hybrid solar cells （HSCs） based on CdSe nanorods （NRs） and the semiconducting polymer PTB7. The power conversion efficiency of HSCs can be significantly enhanced by engineering the polymer/nanocrystal interface with ethanedithiol （EDT） and 1,4-benzenedithiol （1,4-BDT） treatments and reached 2.58% and 2.79%, respectively. These results were preferable to that of a pyridine-coated NR-based device （1.75%）. This improvement was attributed to the thiol groups of EDT and 1,4-BDT, which can tightly coordinate the Cd ions to form Cd-thialate on CdSe NR surfaces, thereby effectively passivating the NR surface and reducing the active layer defects. Therefore, the rate of exciton generation and dissociation was enhanced and led to the improvement of the device performance.

关键词： CdSe nanorods,PTSY,ethanedithiol treatments,1,4-BDT treatments,hybrid solar cells

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Recent advances in photoelectrochemistry-coupled dual-modal biosensors:From constructions to biosensing applications

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Nano Research 2024年第6期17卷 5512-5528页

作者： Yuxiang Dong Weisa Wang Changqing Ye Yanlin Song School of Materials Science and engineering Suzhou University of Science and TechnologySuzhou 215009China Key Laboratory of Green Printing Institute of ChemistryChinese Academy of SciencesBeijing 100190Chin

Precise and sensitive bioanalysis has been the major and urgent pursuit in pathologic diagnosis,food safety,environment monitoring,and drug ***(PEC)bioanalysis,as one of the most promising detection technologies,has rapidly expanded within the field of ***,most of reported PEC analysis approaches still suffer from weak external anti-interference ability,high background,and the risk of false positive or negative errors due to their inherent single-signal *** overcome these shortcomings,new PEC-coupled dual-modal analysis approaches have been developed,where a dual-response signal can be derived through two completely different mechanisms and independent signal transduction *** review introduces the basic principles of PEC biosensing and enumerates and classifies the substrate or probe selections,constructions,and applications of PEC-coupled dual-modal ***,the challenges and developmental prospects of PEC-coupled dual-mode sensing technologies are evaluated and *** hope that this review will provide valuable insights into the latest advancements and practical applications of dual-mode PEC bioanalysis,which will be of great interest to those seeking to stay informed in this field.

关键词： photoelectrochemistry biosensor electrochemistry colorimetry electrochemiluminescence fluorescence dual-mode detection

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Ecologically Inspired Water Network Optimization of Steel Manufacture Using Constructed Wetlands as a Wastewater Treatment Process

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engineering 2018年第4期4卷 567-573页

作者： Kaili Zhang Stephen M. Malone Bert Bras Marc Weissburg Yuehong Zhao Hongbin Cao Institute of Process engineering Chinese Academy of Sciences Beijing 100190 China The George W. Woodruff School of Mechanical engineering Georgia Institute of Technology Atlanta GA 30332 USA School of Biological Sciences Georgia Institute of Technology Atlanta GA 30332 USA

Traditional optimization models often lack a systems-level perspective at conception, which limits their effectiveness. Expanding system boundaries allow scientists and engineers to model complex interactions more accurately, leading to higher efficiency and profitability in industrial systems. Ecological systems have evolved for billions of years under conditions of material and energy shortage, and ecologists have defined analysis tools and metrics for identifying important principles. These principles may provide the framework to circumvent the limitations of traditional optimization techniques. More specifically, by recruiting functional roles that are often found in ecological systems, but are absent in industrial systems, industries can better mimic how natural systems organize themselves. The objective of this analysis is to traditionally optimize a manufacturing process by comparing the model with ecological and resource-based performance metrics in order to redesign the model with the addition of important functional roles that are found throughout nature. Industry partners provided data for this analysis, which involved building a water network for an existing steel manufacturing facility in China. The results of the traditional optimization model indicate a 23%, 29%, and 20% decline in freshwater consumption, wastewater discharge, and total annual cost, respectively. However, our ecologically inspired optimization model provides an additional 21% and 25% decline in freshwater consumption and total annual cost, respectively. Furthermore, no water is discharged. These results suggest that this unconventional approach to optimization could provide an effective technique not used by existing algorithms to solve the challenging problem of pursuing more sustainable industrial systems.

关键词： Phytoremediation Wastewater Steel manufacture Optimization

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Improved power simulation of AlGaN/GaN HEMT at class-AB operation via an RF drain–source current correction method

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Chinese Physics B 2014年第12期23卷 428-434页

作者：林体元庞磊袁婷婷刘新宇 Key Laboratory of Microelectronics Devices & Integrated technology Institute of Microelectronics Chinese Academy of Sciences

A new modified Angelov current–voltage characteristic model equation is proposed to improve the drain–source current（Ids） simulation of an Al Ga N/Ga N-based（gallium nitride） high electron mobility transistor（Al Ga N/Ga N-based HEMT） at high power operation. Since an accurate radio frequency（RF） current simulation is critical for a correct power simulation of the device, in this paper we propose a method of Al Ga N/Ga N high electron mobility transistor（HEMT）nonlinear large-signal model extraction with a supplemental modeling of RF drain–source current as a function of RF input power. The improved results of simulated output power, gain, and power added efficiency（PAE） at class-AB quiescent bias of Vgs =-3.5 V, Vds= 30 V with a frequency of 9.6 GHz are presented.

关键词： AlGaN/GaN HEMT RF drain–source current RF dispersion effect power-added efficiency

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Highly Efficient Continuous-Wave Mid-Infrared Intracavity Singly Resonant Optical Parametric Oscillator Based on MgO：PPLN

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Chinese Physics Letters 2010年第12期27卷 76-78页

作者：颜博霞毕勇周密王栋栋亓岩房涛王斌王延伟郑光成华 academy of Opto-Electronics Chinese Academy of Sciences Beijing 100085 Phoebus Vision Opto-Electronics technology Ltd Beijing 100094 Graduate School of Chinese academy of Sciences Beijing 100049

We present a compact all-solid-state cw mid-infrared intracavity singly resonant optical parametric oscillator （OPO） that is based on a self-fabricated 1-mm-thick 40-mm-long doped MgO periodically poled lithium niobate （MgO：PPLN）. At a diode pump power of 15.6 W, the compact intracavity Nd：YVO4/MgO：PPLN OPO produced 1.9 W output power at 3.19μm, corresponding to conversion efficiency of 12.2% from the laser diode pump to OPO idler output.

关键词： Optics quantum optics and lasers

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