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Uniform Exponential Attractors for Second Order Non-autonomous Lattice Dynamical Systems

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Acta Mathematicae Applicatae Sinica 2017年第3期33卷 587-606页

作者： Xiao-peng ZHOU fu-qi YIN Sheng-fan ZHOU School of Mathematics and Computational Science Xiangtan University Department of Mathematics Zhejiang Normal University

In this paper, the existence of a uniform exponential attractor for a second order non-autonomous lattice dynamical system with quasiperiodic symbols acting on a closed bounded set is considered. Firstly, the existence and uniqueness of solutions for the considered systems which generate a family of continuous processes is shown, and the existence of a uniform bounded absorbing sets for the processes is proved. Secondly, a semigroup defined on a extended space is introduced, and the Lipschitz continuity, a-contraction and squeezing property of this semigroup are proved. Finally, the existence of a uniform exponential attractor for the family of processes associated with the studied lattice dynamical systems is obtained.

关键词： uniform exponential attractor quasiperiodic symbols a family of processes squeezing property lattice dynamical systems

Applications of the Hilbert-Huang Transform for Microtremor Data Analysis Enhancement

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Journal of Earth Science 2015年第6期26卷 799-806页

作者： Lanbo Liu Robert Mehl Weijun Wang qi-fu Chen Department of Civil & Environmental Engineering University University of Connecticut Center for Integrative Geosciences University of Connecticut Institute of Earthquake Science China Earthquake Administration

In this paper we discuss the use of the Hilbert-Huang transform（HHT） to enhance the time-frequency analysis of microtremor measurements. HHT is a powerful algorithm that combines the process of empirical mode decomposition（EMD） and the Hilbert transform to compose the HilbertHuang spectrum that contains the time-frequency-energy information of the recorded signals. HHT is an adaptive algorithm and does not require the signals to be linear or stationary. HHT is advantageous for analyzing microtremor data, since observed microtremors are commonly contaminated by nonstationary transient noises close to the recording instruments. This is especially true when microtremors are measured in an urban environment. In our data processing HHT was used to（1） eliminate the unwanted short-duration transient constituents from microtremor data and use only the coherent portion of the data to carry out the widely used horizontal to vertical spectral ratio（H/V） method;（2） identify and eliminate the continuous industrial noise in certain frequency band; and（3） enhance the H/V analysis by using the Hilbert-Huang spectrum（HHS）. The efficacy of this proposed approach is demonstrated by the examples of applying it to microtremor data acquired in the metropolitan Beijing area.

关键词： Hilbert-Huang transform microtremor time-frequency HN engineering earthquake.

Effect of Temperature on Microstructure and Formability of Al-10 mass% Si Coatings

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Journal of Iron and Steel Research International 2016年第3期23卷 270-275页

作者： Jie ZHANG She-ming JIANG qi-fu ZHANG Chang-sheng LIU National Engineering Laboratory Advanced Coating Technology for Metals Central Iron and Steel Research InstituteBeijing 100081China School of Materials and Metallurgy Northeastern UniversityShenyang 110004LiaoningChina

The type-1aluminized（Al-10mass% Si）coating on hot stamped steel is used in commercial *** effect of temperature on microstructure and formability of the Al-10mass% Si coating was ***-dip aluminized 22MnB5 steel was heated at 870,900,930,and 1 050 ℃ for 5 *** heat treatment at different temperatures,the microstructure of Al-10mass% Si was characterized by field-emission scanning electron microscopy and energy-dispersive *** results show that when the Al-10mass% Si coating was heated at 870℃for 5min,three types of intermetallic phases were formed：two ternary Fe-Si-Al phases（Fe2SiAl7＋Fe2Si2Al5and Fe2SiAl2＋Fe2Si2Al5）and one binary Fe-Al phase（FeAl3）.The phases in the coating became Fe2SiAl2＋Fe2Si2Al5and FeAl3,the binary Fe-Al phase near the interface became Fe2Al5 and the Si-rich layers were decreased with the increase of heating *** the heat treatment was 1 050℃for 5min,the Si-rich layer disappeared,the coating consisted of FeAl and Fe3 Al,and the Kirkendall voids were *** the heating temperature was increased through 870,900,and 930℃,the coating hardness was reduced and cracks were formed in the coating after hot *** formability of the coating with temperature change was confirmed by a hot stamping *** heated at 1 050 ℃,the coating was formable but continuous Kirkendall voids were observed.

关键词： Al-Si coating heating temperature microstructure formability hot-stamping

Upper Semicontinuity and Kolmogorov ε-Entropy of Global Attractor for κ-Dimensional Lattice Dynamical System Corresponding to Klein-Gordon-SchrSdinger Equation

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Acta Mathematicae Applicatae Sinica 2006年第3期22卷 469-486页

作者： fu-qi Yin Sheng-fan Zhou Department of Mathematics Xiangtan University Xiangtan 411105 China Mathematics and Science College Shanghai Normal University Shanghai 200234 China

In this paper, we establish the existence of a global attractor for a coupled κ-dimensional lattice dynamical system governed by a discrete version of the Klein-Gordon-SchrSdinger Equation. An estimate of the upper bound of the Kohnogorov ε-entropy of the global attractor is made by a method of element decomposition and the covering property of a polyhedron by balls of radii ε in a finite dimensional space. Finally, a scheme to approximate the global attractor by the global attractors of finite-dimensional ordinary differential systems is presented .

关键词： Global attractor lattice dynamical system element decomposition Kolmogorov ε-entropy upper semicontinuity

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基于自研光谱仪的痕量气体光解速率测量研究

光谱学与光谱分析 2025年第1期45卷 15-23页

作者：李浩然曾议朱磊窦科刘志宏常振江宇司福祺中国科学院合肥物质科学研究院安徽光学精密机械研究所环境科学与技术重点实验室安徽合肥230031 中国科学技术大学科学岛分院安徽合肥230026 合肥大学生物食品与环境学院安徽合肥230601

光解速率及其测量技术最早由德国科学家提出,21世纪初Metcon公司开发了光解速率测量仪,该技术在国内得到关注,部分高校和公司对光解速率测量系统开展了研究和开发。国外产品一般体积较大,价格昂贵。国内产品中光谱仪、接收器等核心器件... 详细信息

光解速率及其测量技术最早由德国科学家提出,21世纪初Metcon公司开发了光解速率测量仪,该技术在国内得到关注,部分高校和公司对光解速率测量系统开展了研究和开发。国外产品一般体积较大,价格昂贵。国内产品中光谱仪、接收器等核心器件仍依赖于国外进口,易受国外技术封锁影响。在我国“十四五”国家重点研发计划中“大气与土壤、地下水污染综合治理”重点专项对化学气候综合站检测技术与装备需求引导下,研制了测量大气物质光解速率的光谱仪系统,并满足其核心部件国产化的要求。系统采用自主设计的小型光谱仪作为核心部件,配合各向均匀响应的光学接收器,经实验室光学定标后测得各种物质的光解速率。该系统工作波段为285~430 nm,时间分辨率可达0.1 s,可测物质包括NO_(2)、HONO、HCHO、H_(2)O_(2)等,与国外进口测量仪器对比,各气体物质光解速率的测量误差小于5%,相关性均超过0.93。采用该系统在合肥市董铺岛对大气中气体光解速率开展了长时间的连续监测。对NO_(2)光解速率变化趋势以及NO_(2)光解速率与浓度间的相关性进行分析,发现光解反应与驱动光化反应的能量密切相关,晴天的光解速率数值明显高于阴天与雨天。发现NO_(2)光解速率与浓度的积分曲线间存在一种经验公式,相关性大于0.9,可通过测量NO_(2)光解速率对NO_(2)浓度的累积量进行估计。该系统实现了核心部件的国产化,整体结构简单、便携,方便外场试验安装的同时,降低成本,提高经济性。研究为大气污染综合监测治理提供数据支撑,对各地区的环境监测及污染预防具有参考意义。

关键词：光解速率光谱仪辐亮度光学接收器

Current status and future prospects of stem cell therapy in Alzheimer’s disease

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Neural Regeneration Research 2020年第2期15卷 242-250页

作者： fu-qiang Zhang Jin-Lan Jiang Jing-Tian Zhang Han Niu Xue-qi fu Lin-Lin Zeng Scientific Research Centre of China-Japan Union Hospital Jilin UniversityChangchunJilin ProvinceChina School of Life Sciences Jilin UniversityChangchunJilin ProvinceChina

Alzheimer’s disease is a common progressive neurodegenerative disorder, pathologically characterized by the presence of β-amyloid plaques and neurofibrillary tangles. Current treatment approaches using drugs only alleviate the symptoms without curing the disease, which is a serious issue and influences the quality of life of the patients and their caregivers. In recent years, stem cell technology has provided new insights into the treatment of neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. Currently, the main sources of stem cells include neural stem cells, embryonic stem cells, mesenchymal stem cells, and induced pluripotent stem cells. In this review, we discuss the pathophysiology and general treatment of Alzheimer’s disease, and the current state of stem cell transplantation in the treatment of Alzheimer’s disease. We also assess future challenges in the clinical application and drug development of stem cell transplantation as a treatment for Alzheimer’s disease.

关键词： Alzheimer's disease β-amyloid drug development embryonic stem cells induced pluripotent stem cells mesenchymal stem cells nerve regeneration neural regeneration neural stem cells neurodegenerative disorders stem cell therapy

The First Spectral Analysis of Solar Radio Spike Event

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Chinese Physics Letters 2000年第6期17卷 460-462页

作者： XU fu-Ying LIU Yu-Ying fu qi-jun WU Hong-Ao Purple Mountain Observatory Chinese Academy of SciencesNanjing 210008 Beijing Astronomical Observatory Chinese Academy of SciencesBeijing 100012 National Astronomical Observatories Chinese Academy of Sciences

The first spectral analysis of a spike event has been *** was found that the peak frequency of spectrum of the spike event on Oct.2,1993 drifted from higher to lower frequency for the first group of spikes,but the frequency remained almost the same for the second *** if the mean energy of electron beam is a monotonic or random function of time and its pitch angle is a monotonically decreasing function of mean energy,then the different observed characteristics of evolution of the peak frequency with time may be interpreted by the location of resonant *** spike radio emissions with one and the same peak frequency probably originated from the same region of electron cyclotron maser instability.

关键词： originated monotonic spectrum

Characterization of chemical composition of high viscosity heavy oils:Macroscopic properties, and semi-quantitative analysis of molecular composition using high-resolution mass spectrometry

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Petroleum Science 2024年第5期21卷 3612-3620页

作者： Jian-Xun Wu Shuo-Fan Li qi-fu Li Feng Yan qi-Lin Zhou Shuai Ma Ya-He Zhang Suo-qi Zhao Quan Shi State Key Laboratory of Heavy Oil Processing Petroleum Molecular Engineering Center(PMEC)China University of PetroleumBeijing102249China PipeChina Institute of Science and Technology Tianjin300457China

Heavy oil is an important resource in current petroleum exploitation, and the chemical composition information of heavy oil is crucial for revealing its viscosity-inducing mechanism and solving practical exploitation issues. In this study, the techniques of high-temperature gas chromatography and high-resolution mass spectrometry equipped with an electrospray ionization source were applied to reveal the chemical composition of typical heavy oils from western, central, and eastern China. The results indicate that these heavy oils display significant variations in their bulk properties, with initial boiling points all above 200℃. Utilizing pre-treatment and ESI high-resolution mass spectrometry, an analysis of the molecular composition of saturated hydrocarbons, aromatic hydrocarbons, acidic oxygen compounds, sulfur compounds, basic nitrogen compounds, and neutral nitrogen compounds within the heavy oil was conducted. Ultimately, a semi-quantitative analysis of the molecular composition of the heavy oil was achieved by integrating the elemental content. The semi-quantitative analysis results of Shengli-J8 heavy oil and a conventional Shengli crude oil show that Shengli-J8 heavy oil lacks alkanes and low molecular weight aromatic hydrocarbons, which contributes to its high viscosity. Additionally,characteristic molecular sets for different heavy oils were identified based on the semi-quantitative analysis of molecular composition. The semi-quantitative analysis of molecular composition in heavy oils may provide valuable reference data for establishing theoretical models on the viscosity-inducing mechanism in heavy oils and designing viscosity-reducing agents for heavy oil exploitation.

关键词： Heavy oil HRMS Molecular composition Semi-quantitative analysis Viscosity

Development of Continuous Coating and Plating Strip Steel

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Journal of Iron and Steel Research International 2001年第2期8卷 34-41页

作者： ZHANG qi-fu HUANG Jian-zhong ZHAO Pei ZHONG Hai-feng Central Iron & Steel Research Institute

The development trend of coated and plated technology for continuous strip steels,which include hot dip plating,electroplating,organic coating and vacuum plating technology,were summarized.

关键词： strip steel coating technology plating technology development