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Population-influenced spatiotemporal pattern of natural disaster and social crisis in China, AD1–1910

Science China Earth Sciences 2019年第7期62卷 1138-1150页

作者： Shengda zhang David dian zhang Department of Geography The University of Hong Kong School of Geographical Sciences Guangzhou University

Researchers mostly ascribe contemporary natural disaster and the concomitant social crisis to anomalous climate change or global warming. However, whether such a relationship is still valid in long-term historical settings remains doubtful. In this study, data obtained from historical records about natural calamities(flood and drought) and their social impacts(famine,cannibalism, and war) at provincial and decadal scales during AD1–1910 are applied to mathematical statistics such as correlation and regression analysis as well as spatial visualization. Also, the role of population in the nexus of meteorological catastrophes and human miseries is investigated. Results show that at the provincial scale, generally there is high consistency among different variables and most of them are clustered in eastern part of China, especially in the north. More in-depth examinations indicate regional disparities that variables account for higher proportion in the south during the later imperial era,which may be attributed to the southward movement of population center. At the decadal scale, drought is the primary contributor to famine and cannibalism, while severe or even out-of-control famine i.e. cannibalism is more likely to incur war than ordinary famine per se. Besides, population growth rate exerts its positive effect on natural hazards and food crises, whereas more wars bring population loss and relieve population stress despite the weak negative association. These findings supplement previous views and confirm that the distributions of disasters in ancient China are affected by population rather than climatic variability, which only determines the occurrence of disaster.

关键词： Natural disaster Social crisis Population Spatiotemporal pattern Historical China

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Global Stability of a Viral Infection Model with Defectively Infected Cells and Latent Age

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Chinese Annals of Mathematics,Series B 2024年第4期45卷 555-572页

作者： Jianquan LI Yuming CHEN Peijun zhang dian zhang School of Computer Science Xijing UniversityXi’an 710123China Department of Mathematics Wilfrid Laurier UniversityWaterlooON N2L 3C5Canada Corresponding author.Xi’an Key Laboratory of Human-Machine Integration and Control Technology for Intelligent Rehabilitation Xijing UniversityXi’an 710123China Equal contributor.Department of Immunology Xi’an Medical UniversityXi’an 710021China

The authors propose and analyze a viral infection model with defectively infected cells and age of the latently infected *** existence of steady states is determined by the basic reproduction number of *** the Lyapunov's direct method,they establish a threshold dynamics of the model with the basic reproduction number of virus as the threshold *** achieve it,a novel procedure is *** novelties are *** one hand,the coefficients involved in the specific forms of the used Lyapunov functionals for the two feasible steady states are determined by the same set of *** the other hand,for the infection steady state,a new approach is proposed to check whether the derivative of the Lyapunov functional candidate along solutions is negative(semi-)definite or *** procedure not only simplifies the analysis but also exhibits the relationship between the two Lyapunov functionals for the two feasible steady ***,the procedure is expected to be applicable for other similar models.

关键词： Viral infection model Basic reproduction number Equilibrium Global stability Lyapunov direct method Age structure

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A Radio-Telemetry System for Navigation and Recording Neuronal Activity in Free-Roaming Rats

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Journal of Bionic Engineering 2012年第4期9卷 402-410页

作者： dian zhang Yanling Dong Megan Li Houjun Wang School of Automation Engineering University of Electronic Science and Technology of China Chengdu 611731 P. R. China School of Medicine Qingdao University Qingdao 266071 P R. China Shandong Eye Institute Qingdao 266071 P. R. China Zanvyl Krieger School of Arts and Sciences The Johns Hopkins University Baltimore 21218 USA

A radio-telemetry recording system is presented which is applied to stimulate specific brain areas and record neuronal ac- tivity in a free-roaming rat. The system consists of two major parts： stationary section and mobile section. The stationary section contains a laptop, a Micro Control Unit （MCU）, an FM transmitter and a receiver. The mobile section is composed of the headstage and the backpack （which includes the mainboard, FM transmitter, and receiver）, which can generate biphasic mi- crocurrent pulses and simultaneously acquire neuronal activity. Prior to performing experiments, electrodes are implanted in the Ventral Posterolateral （VPL） thalamic nucleus, primary motor area （M1） and Medial Forebrain Bundle （MFB） of the rat. The stationary section modulates commands from the laptop for stimulation and demodulates signals for neuronal activity recording. The backpack is strapped on the back of the rat and executes commands from the stationary section, acquires neuronal activity, and transmits the neuronal activity singles of the waking rat to the stationary section. All components in the proposed system are commercially available and are fabricated from Surface Mount Devices （SMD） in order to reduce the size （25 mm×15 mm ×2 mm） and weight （10 g with battery）. During actual experiments, the backpack, which is powered by a rechargeable Lithium battery （4 g）, can generate biphasic microcurrent pulse stimuli and can also record neuronal activity via the FM link with a maximum transmission rate of 1 kbps for more than one hour within a 200 m range in an open field or in a neighboring chamber. The test results show that the system is able to remotely navigate and control the rat without any prior training, and acquire neuronal activity with desirable features such as small size, low power consumption and high precision when compared with a commercial 4-channel bio-signal acquisition and processing system.

关键词： bio-robot radio-telemetry microcurrent stimulation navigation neuronal activity recording

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Precise Transceiver-Free Localization in Complex Indoor Environment

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China Communications 2016年第5期13卷 28-37页

作者： Rui Mao Peng Xiang dian zhang College of Computer Science and Software Shenzhen University

Transceiver-free object localization can localize target through using Radio Frequency(RF) technologies without carrying any device, which attracts many researchers' attentions. Most traditional technologies usually first deploy a number of reference nodes which are able to communicate with each other, then select only some wireless links, whose signals are affected the most by the transceiver-free target, to estimate the target position. However, such traditional technologies adopt an ideal model for the target, the other link information and environment interference behavior are not considered comprehensively. In order to overcome this drawback, we propose a method which is able to precisely estimate the transceiver-free target position. It not only can leverage more link information, but also take environmental interference into account. Two algorithms are proposed in our system, one is Best K-Nearest Neighbor(KNN) algorithm, the other is Support Vector Regression(SVR) algorithm. Our experiments are based on Telos B sensor nodes and performed in different complex lab areas which have many different furniture and equipment. The experiment results show that the average localization error is round 1.1m. Compared with traditional methods, the localization accuracy is increased nearly two times.

关键词： indoor localization transceiver-free radio map support vector regression

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A Precise RFID Indoor Localization System with Sensor Network Assistance

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China Communications 2015年第4期12卷 13-22页

作者： zhang dian LU Kezhong MAO Rui Guangdong Province Key Laboratory of Popular High Performance Computers College of Computer Science and Software EngineeringShenzhen University

Indoor localization is very critical for medical care applications, e.g., the patient localization or tracking inside the building of the hospital. Traditional Radio Frequency Identification(RFID) technologies are very popular in this area since their cost is very low. In such technologies, each tag acts as the transmitter and the Radio Signal Strength Indicator(RSSI) information is measured from the readers. However, RSSI information suffers severely from the multi- path phenomenon. As a result, if in a very large area, the localization accuracy will be affected seriously. In order to solve this problem, we introduce Wireless Sensor Networks(WSNs) with only a few nodes, each of which acts as both transmitter and receiver. In such networks, the change of signal strength(referred as dynamic of RSSI) is leveraged to select a cluster of reference tags as candidates. Then the fi nal target location is estimated by using the RSSI relationships between the target tag and candidate reference tags. Thus, the localization accuracy and scalability are able to be improved. We proposed two algorithms, SA-LANDMARC, and COCKTAIL. Experiments show that the localization accuracy of the two algorithms can reach 0.7m and 0.45 m, respectively. Compared to most traditional Radio Frequency(RF)-based approaches, the localization accuracy is improved at least 50%.

关键词： radio frequency RFID wirelesssensor networks hybrid support vectorregression

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Microstructure and Mechanical Properties of Semi-continuous Equal-channel Angular Extruded Interstitial-free Steel

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Journal of Iron and Steel Research International 2016年第2期23卷 160-165页

作者： Bo YAN Si-hai JIAO dian-hua zhang State Key Laboratory of Rolling and Automation Northeastern University Research and Development Center Baoshan Iron and Steel Co.Ltd.

An innovative method called semi-continuous equal channel angular extrusion （SC-ECAE） has been devel- oped to produce ullrafine grained steel by inducing severe plastic deformation. In contrast to the external forces that are exerted on specimens in traditional ECAE, the driving forces are applied on the dies in the novel SC EACE process. Commercial interslitial-free steel sheets with width of 160 mm and tbickness of 2 mm were processed re peatedly to various passes at room temperature using this method. The microstructural evolution was characterized using high-resolution electron backscatter diffraction （EBSD）, and the mechanical properties were investigated by tensile testing. The EBSD images indicated that the fraction of high angle boundaries （HABs） began to increase gradually after four passes; after six passes, elongated HAB structures with nearly submicron-scale average spacings were formed. The tensile testing results showed that strengthening was accompanied by a decrease in tensile ductili- ly, but no significant anisotropy was observed. After 10 passes, a final HAB fraction of about 90% and an overall grain size of 0.55 μm, yield strength of 638.7 MPa, an ultimate tensile strength （UTS） of 710.3 MPa, and a totfd elongation of 12.0 % were obtained.

关键词： severe plastic deformation semi-continuous equal channel angular extrusion IF steel ultrafine grainedstructure EBSD

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Weak-force sensing with squeezed optomechanics

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Science China(Physics,Mechanics & Astronomy) 2020年第2期63卷 71-81页

作者： Wen Zhao Sheng-dian zhang Adam Miranowicz Hui Jing Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and ApplicationsHunan Normal UniversityChangsha 410081China College of Physics and Materials Science Henan Normal UniversityXinxiang 453007China Faculty of Physics Adam Mickiewicz UniversityPozna´n 61-614Poland

We investigate quantum-squeezing-enhanced weak-force sensing via a nonlinear optomechanical resonator containing a movable mechanical mirror and an optical parametric amplifier(OPA). Herein, we determined that tuning the OPA parameters can considerably suppress quantum noise and substantially enhance force sensitivity, enabling the device to extensively surpass the standard quantum limit. This indicates that under realistic experimental conditions, we can achieve ultrahigh-precision quantum force sensing by harnessing nonlinear optomechanical devices.

关键词： weak-force sensing squeezing optomechanics

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Adaptive threading strategy based on rolling characteristics analysis in hot strip rolling

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Journal of Central South University 2017年第7期24卷 1560-1572页

作者： PENG Wen CHEN Shu-zong GONG dian-yao LIU Zi-ying zhang dian-hua State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China Research Institute of Technology Shougang GroupBeijing 100041China

In order to improve the threading stability and the head thickness precision in tandem hot rolling process, an adaptive threading strategy was proposed. The proposed strategy was realized by the rolling characteristics analysis, and factors which affect the rolling force and the final thickness were determined and analyzed based on the influence coefficients calculation process. An objective function consisting of the influenced factors was founded, and the disturbance quantity was obtained by minimizing the function with the Nelder-Mead simplex method, and the proposed adaptive threading strategy was realized based on the calculation results. The adaptive threading strategy has been applied to one 7-stand hot tandem mill successfully, actual statistics data show that the predicted rolling force prediction in the range of +/- 5.0% is improved to 97.8%, the head thickness precision in the range of +/- 35 mu m is improved to 98.5%, and the threading stability and the head thickness precision are enhanced to a high level.

关键词： hot strip rolling adaptive threading rolling characteristics analysis influence coefficients method simplex algorithm

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Sn_(4)P_(3)-induced crystalline/amorphous composite structures for enhanced sodium-ion battery anodes

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Journal of Materials Science & Technology 2020年第20期52卷 73-80页

作者： Jaffer Saddique Xu zhang Tianhao Wu Heng Su Shiqi Liu dian zhang Yuefei zhang Haijun Yu College of Materials Science and Engineering Key Laboratory of Advanced Functional Materials of Education Ministry of ChinaBeijing University of TechnologyBeijing 100124China Institute of Microstructure and Property of Advanced Materials Beijing University of TechnologyBeijing 100124China

The optimization of anode materials such as Sn,P and Sn4P3 in terms of capacity and cyclability is crucial to improve the overall performance of sodium-ion ***,the delicate fabrication of these materials,including the balanced crystalline/amorphous domains,reasonable particle size and distribution,complementary components exhibiting synergetic reactions,among others,still greatly retards the realization of maximum ***,a series of Sn/P-based composite materials with a plum pudding configuration were fabricated to achieve controlled crystalline/amorphous structures as well as optimized size and distribution in a carbon *** using a facile and low-cost ball milling method,the structural transformation of Sn4P3 into phase-separated crystalline Sn and amorphous P in a carbonaceous framework can be finely controlled,producing a series of binary(Sn4 P3/C),quaternary(Sn4P3/Sn/P/C) and ternary(Sn/P/C) *** to the complementary components,crystalline/amorphous adjustment,crystallite sizes and well-integrated interfaces,the quaternary Sn4P3/Sn/P/C composite showed the best electrochemical performance,with a noticeable long-cycle performance of 382 mA hg-1 and 86% capacity retention for nearly 300 *** from binary and ternary composites,the discharge of quaternary composite generates no noticeable signals of Na15Sn4 and Na3 P in the ex-situ X-ray diffraction patterns,suggesting the crystallite growth of sodiation products can be ***,Sn4 P3 in the quaternary composite can be partially regenerated in the desodiation reaction,implying the significant short-range interaction and thus better synergetic reactions between Sn and P *** results demonstrate that the design and organization of crystalline/amorphous structures can serve as an efficient strategy to develop novel electrode materials for sodium ion batteries.

关键词： Sodium ion battery Tin phosphides Anode materials Composite structure Reaction mechanism

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A Kind of Plate Laminar Cooling Strategy With High Response and Steady Precision

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Journal of Iron and Steel Research International 2010年第1期17卷 18-21,37页

作者： zhang dian-hua ZHOU Na WANG Bing-xing zhang Meng State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

After Smith Predictor being used to laminar cooling system, the control law for integral regulators is introduced. New notion of plate sample length is given for evading the delay time varying with the roll table speed. It is found that the integral algorithm is more controllable for system regulating process and has better steady state precision. Compared with the traditional control strategies, the new control law has faster response speed and higher steady state precision. The controller can be regulated in shorter time and the response is faster than that of routine controller and it can effectively eliminate the oscillatory instability. Owing to its easy realization and high stability, it has been applied to a plate mill. The accuracy of finish cooling temperature can be controlled within ± 10 ℃.

关键词： plate laminar cooling Smith Predictor time delay system

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