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Modelling envelope and temporal fine structure components of frequency-following responses in rat inferior colliculus

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Science China(Technological Sciences) 2017年第7期60卷 966-973页

作者： wang Qian LI Liang School of Psychological and Cognitive Sciences and Beijing Key Laboratory of Behavior and Mental Health Peking UniversityBeijing 100871China Beijing Key Laboratory of Epilepsy Epilepsy Center Department ofFunetional NeurosurgerySanbo Brain HospitalCapital Medical UniversityBeijing 100093China Speech and Hearing Research Center Key Laboratory on Machine Perception(Ministry of Education)Peking UniversityBeijing 100871China Beijing Institute for Brain Disorders Beijing 100081China

In studies of auditory perception, a dichotomy between envelope and temporal fine structure(TFS) has been emphasized. It has been shown that frequency-following responses(FFRs) in the rat inferior colliculus can be divided into the envelope component(FFREnv)and the temporal fine structure component(FFRTFS). However, the existing FFR models cannot successfully separate FFREnv and FFRTFS. This study was to develop a new FFR model to effectively distinguish FFREnv from FFRTFS by both combining the advantages of the two existing FFR models and simultaneously adding cellular properties of inferior colliculus neurons. To evaluate the validity of the present model, correlations between simulated FFRs and experimental data from the rat inferior colliculus were calculated. Different model parameters were tested, FFRs were calculated, and the parameters with highest prediction were chosen to establish an ideal FFR model. The results indicate that the new FFR model can provide reliable predictions for experimentally obtained FFREnv and FFRTFS.

关键词： frequency-following response envelope temporal fine structure inferior colliculus

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水热均匀沉淀法制备不同粒径的纳米氧化镁

中国陶瓷 2020年第8期56卷 26-32页

作者：王锐王珊珊薛永强山西工程职业学院化工系太原030009 太原理工大学应用化学系太原030024

纳米氧化镁(nano-MgO)在陶瓷、水处理、催化和材料等领域有着十分广泛的应用,不同粒径的nano-MgO具有不同的特性和应用范围。以MgCl2为镁源,尿素为沉淀剂,聚乙二醇为分散剂,首次采用水热均匀沉淀法研究了nano-MgO的制备,考察了反应物浓... 详细信息

纳米氧化镁(nano-MgO)在陶瓷、水处理、催化和材料等领域有着十分广泛的应用,不同粒径的nano-MgO具有不同的特性和应用范围。以MgCl2为镁源,尿素为沉淀剂,聚乙二醇为分散剂,首次采用水热均匀沉淀法研究了nano-MgO的制备,考察了反应物浓度、反应物配比、反应温度和焙烧温度对nano-MgO粒径的影响;根据这些影响规律,制备出了不同粒径的nano-MgO,并对其纯度、粒径、晶体结构和形貌进行了表征。研究结果表明:采用水热均匀沉淀法,通过控制制备条件,可以制备出不同粒径的nano-MgO粉体;制备条件对nano-MgO粒径有显著的影响,反应温度和焙烧温度升高,nano-MgO的粒径增大;增大反应物浓度,nano-MgO粒径先增大后减小;MgCl2与尿素的配比增大,nano-MgO的粒径先减小后增大。这些实验结果为纳米氧化镁的制备、研究和应用提供了重要的参考。

关键词： Nano-MgO 不同粒径水热均匀沉淀法可控制备

Code constructions for multi-node exact repair in distributed storage

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Science China(Information Sciences) 2018年第10期61卷 80-97页

作者： Marwen ZORGUI Zhiying wang Center for Pervasive Communications and Computing(CPCC) Department of Electrical Engineering and Computer Science University of California at Irvine

We study the problem of centralized exact repair of multiple failures in distributed *** present constructions that achieve a new set of interior points under exact repair. The constructions build upon the layered code construction by Tian et al., designed for exact repair of single failure. We firstly improve upon the layered construction for general system parameters. Then, we extend the improved construction to support the repair of multiple failures, with varying number of helpers. In particular, for some parameters, we prove the optimality of one point in terms of the storage size and the repair bandwidth for multiple erasures. Finally, considering minimum bandwidth cooperative repair(MBCR) codes as centralized repair codes, we determine explicitly the best achievable region obtained by space-sharing among all known points, including the MBCR point.

关键词： regenerating codes exact repair multiple failures interior points Steiner systems

Large-scale video compression： recent advances and challenges

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Frontiers of Computer Science 2018年第5期12卷 825-839页

作者： Tao TIAN Hanli wang Department of Computer Science and Technology Tongji University Shanghai 201804 China Key Laboratory of Embedded System and Service Computing Ministry of Education Tongji University Shanghai 200092 China Shanghai Engineering Research Center of Industrial Vision Perception & Intelligent Computing Shanghai 200092 China

The evolution of social network and multimedia technologies encourage more and more people to generate and upload visual information, which leads to the generation of large-scale video data. Therefore, preeminent compression technologies are highly desired to facilitate the storage and transmission of these tremendous video data for a wide variety of applications. In this paper, a systematic review of the recent advances for large-scale video compression （LSVC） is presented. Specifically, fast video coding algorithms and effective models to improve video compression efficiency are introduced in detail, since coding complexity and compression efficiency are two important factors to evaluate video coding approaches. Finally, the challenges and fu- ture research trends for LSVC are discussed.

关键词： large-scale video compression fast video coding compression efficiency

A SPLINE METHOD FOR SOLVING TWO-DIMENSIONAL FREDHOLM INTEGRAL EQUATION OF SECOND KIND WITH THE HYPERSINGULAR KERNEL

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Journal of Computational Mathematics 2001年第3期19卷 225-230页

作者： wang, RH Lu, Y Dalian Univ Technol Inst Math Sci Dalian 116024 Peoples R China

Provides information on a study which proposed a spline method for solving two-dimensional Fredholm Integral Equations of second kind space with hypersingular kernels. Details on the quasi-interpolating operators; Inf... 详细信息

关键词： hypersingular integral finite-part integral quasi-interpolating operator nonuniform type-2 triangulation

Design of complex FIR filters with arbitrary magnitude and group delay responses

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Journal of Systems Engineering and Electronics 2009年第5期20卷 942-947页

作者： wang Xiaohua He Yigang Electrical and Information Engineering Coll. Changsha Univ. of Science & Technology Changsha 410077 P. R. China Electrical and Information Engineering Coll. Hunan Univ. Changsha 410082 P. R. China

To design approximately linear-phase complex coefficient finite impulse response （FIR） digital filters with arbitrary magnitude and group delay responses, a novel neural network approach is studied. The approach is based on a batch back-propagation neural network algorithm by directly minimizing the real magnitude error and phase error from the linear-phase to obtain the filter＇s coefficients. The approach can deal with both the real and complex coefficient FIR digital filters design problems. The main advantage of the proposed design method is the significant reduction in the group delay error. The effectiveness of the proposed method is illustrated with two optimal design examples.

关键词： signal processing digital filter neural network complex coefficient filter optimal design finite impulse response.

A critical review of preparation design and workability measurement of concrete material for largescale 3D printing

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Frontiers of Structural and Civil Engineering 2018年第3期12卷 382-400页

作者： Guowei MA Li wang College of Architecture and Civil Engineering Beijing University of Technology Beijing 100124 China School of Civil Environmental and Mining Engineering The University of Western Australia Crawley WA 6009 Australia School of Mechanics and Civil engineering China University of Mining & Technology at Beijing Beijing 100083 China

In recent few years, significant improvement has been made in developing largescale 3D printers to accommodate the need of industrial-scale 3D printing. It is of great feasibility to construct structural components and buildings by means of 3D concrete printing. The major issues of this innovative technique focus on the preparation and optimization of concrete materials which possess favourable printable properties as well as the measurement and evaluation methods of their workability. This paper firstly introduces three largescale 3D printing systems that have been successfully applied in construction industry. It then summarizes the commonly used raw materials in concrete manufacturing. Critical factors that should be particularly controlled in material preparation are specified. Easy-extrusive, easy-flowing, well-buildable, proper setting time and low shrinkage are significant for concrete mixture to meet the critical requirements of a freeform construction process. Thereafter, measuring methods that can be employed to assess the fresh and hardened properties of concrete at early stages are suggested. Finally, a few of evaluation methods are presented which may offer certain assistance for optimizing material preparation. The objective of this work is to review current design methodologies and experimental measurement and evaluation methods for 3D printable concrete materials and promote its responsible use with largescale 3D printing technology.

关键词： 3D printing concrete material printable property workability measurement construction automation

Shock wave configurations and reflection hysteresis outside a planar Laval nozzle

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Chinese Journal of Aeronautics 2015年第5期28卷 1362-1371页

作者： wang Dan Yu Yong School of Aerospace Engineering Beijing Institute of Technology

When the pressure ratio increases from the perfectly expanded condition to the third limited condition in which a normal shock is located on the exit plane, shock wave configurations outside the nozzle can be further assorted as no shock wave on the perfectly expanded condition, weak oblique shock reflection in the regular reflection （RR） pressure ratio condition, shock reflection hysteresis in the dual-solution domain of pressure ratio condition, Mach disk configurations in the Mach reflection （MR） pressure ratio condition, the strong oblique shock wave configurations in the corresponding condition, and a normal shock forms on the exit plane in the third limited con- dition. Every critical pressure ratio, especially under regular reflection and Mach reflection pressure ratio conditions, is deduced in the paper according to shock wave reflection theory. A hysteresis phenomenon is also theoretically possible in the dual-solution domain. For a planar Laval nozzle with the cross-section area ratio being 5, different critical pressure ratios are counted in these con- ditions, and numerical simulations are made to demonstrate these various shock wave configurations outside the nozzle. Theoretical analysis and numerical simulations are made to get a more detailed understanding about the shock wave structures outside a Laval nozzle and the RR←→MR transition in the dual-solution domain.

关键词： Critical pressure ratios Hysteresis Mach reflection Regular reflection Shock wave configurations

Effects of solution conditions on the physicochemical properties of stratification components of extracellular polymeric substances in anaerobic digested sludge

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Journal of Environmental Sciences 2013年第1期25卷 155-162页

作者： Dongqin Yuan Yili wang College of Environmental Science and Engineering Beijing Key Lab for Source Control Technology of Water PollutionBeijing Forestry University

The composition and effects of solution conditions on the physicochemical properties of the stratification components of extracellular polymeric substances （EPS） in anaerobic digested sludge were determined. The total EPS in anaerobic digested sludge were extracted by the cation exchange resin method. Another EPS extraction method, the ceutrifugation and sonication technique was employed to stratify the EPS into three fractions： slime, loosely bound （LB）-EPS, and tightly bound （TB）-EPS from the outside to the inside of the anaerobic digested sludge. Proteins and polysaccharides were dispersed uniformly across the different EPS fractions, and humic-like substances were mainly partitioned in the slime, with TB-EPS second. Protein was the major constituent of the LB-EPS and TB-EPS, and the corresponding ratios ranged from 54.0% to 65.6%. The hydrophobic part in the EPS chemical components was primarily comprised of protein and DNA, while the hydrophilic part was mainly composed of polysaccharide. In the slime, the hydrophobic values of several EPS chemical components （protein, polysaccharide, humic-like substances and DNA） were all below 50%. The protein/polysaccharide ratio had a significant influence on the Zeta potentials and isoelectric point values of the EPS： the greater the protein/polysaccharide ratio of the EPS was, the greater the Zeta potential and the higher the isoelectric point value were. All Zeta potentials of the EPS showed a decreasing trend with increasing pH. The corresponding isoelectric point values （pH） were 2.8 for total EPS, 2.2 for slime, 2.7 for LB-EPS, and 2.6 for TB-EPS. As the ionic strength increased, the Zeta potentials sharply increased and then gradually became constant without charge reversal. In addition, as the temperature increased （〈 40℃）, the apparent viscosity of the EPS decreased monotonically and then gradually became stable between 40 and 60℃.

关键词： anaerobic digested sludge extracellular polymeric substances stratification components physicochemical properties solution conditions