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Changes in brain functional network connectivity after stroke

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Neural Regeneration Research 2014年第1期9卷 51-60页

作者： Wei li yapeng li Wenzhen Zhu Xi Chen Key Laboratory of Image Processing and Intelligent Control Ministry of Education Department of Control Science and Engineering Huazhong University of Science and Technology Department of Radiology Tongji HospitalTongji Medical CollegeHuazhong University of Science and Technology

Studies have shown that functional network connection models can be used to study brain net- work changes in patients with schizophrenia. In this study, we inferred that these models could also be used to explore functional network connectivity changes in stroke patients. We used independent component analysis to find the motor areas of stroke patients, which is a novel way to determine these areas. In this study, we collected functional magnetic resonance imaging datasets from healthy controls and right-handed stroke patients following their first ever stroke. Using independent component analysis, six spatially independent components highly correlat- ed to the experimental paradigm were extracted. Then, the functional network connectivity of both patients and controls was established to observe the differences between them. The results showed that there were 11 connections in the model in the stroke patients, while there were only four connections in the healthy controls. Further analysis found that some damaged connections may be compensated for by new indirect connections or circuits produced after stroke. These connections may have a direct correlation with the degree of stroke rehabilitation. Our findings suggest that functional network connectivity in stroke patients is more complex than that in hea- lthy controls, and that there is a compensation loop in the functional network following stroke. This implies that functional network reorganization plays a very important role in the process of rehabilitation after stroke.

关键词： nerve regeneration brain injury stroke motor areas functional magnetic resonanceimaging brain network independent component analysis functional network connectivity neuralplasticity NSFC grant neural regeneration

An improved strain-softening constitutive model of granite considering the effect of crack deformation

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1202-1215页

作者： yapeng li Qiang Zhang Qiuxin Gu Peinan Wu Binsong Jiang State Key Laboratory for Geomechanics and Deep Underground Engineering School of Mechanics and Civil EngineeringChina University of Mining and TechnologyXuzhou221116China

This paper presents an improved strain-softening constitutive model considering the effect of crack deformation based on the triaxial cyclic loading and unloading test *** improved model assumes that total strain is a combination of plastic,elastic,and crack *** constitutive relationship between the crack strain and the stress was further *** evolutions of mechanical parameters,*** parameters,dilation angle,unloading elastic modulus,and deformation parameters of crack,with the plastic strain and confining pressure were *** the increase in plastic strain,the cohesion,friction angle,dilation angle,and crack Poisson's ratio initially increase and subsequently decrease,and the unloading elastic modulus and the crack elastic modulus nonlinearly *** increasing confining pressure enhances the strength and unloading elastic modulus,and decreases the dilation angle and Poisson's ratio of the *** theoretical triaxial compressive stress-strain curves were compared with the experimental results,and they present a good agreement with each *** improved constitutive model can well reflect the nonlinear mechanical behavior of granite.

关键词： Strain-softening Crack deformation effect Plastic shear strain Constitutive model

Synthesis and characterization of triblock copolymer by combining enzymatic condensation polymerization and ATRP

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Chinese Science Bulletin 2006年第9期51卷 1065-1068页

作者： li Dongshuang SHA Ke li yapeng WANG Shuwei WANG Jingyuan Department of Chemistry Jilin University Changchun 130023 China

The polyester poly(1,10-decanediol /1, 10-sebacate) (PSD) was synthesized by means of Novozyme 435 catalyzed condensation polymeriza- tion of 1,10-decanediol and 1,10-sebacic acid. Both hydroxyl chain ends of the resulting PSD were modi- fied by esterification with α-bromopropionyl bromide to obtain difunctional macroinitiator, which was sub- sequently used in the ATRP of S t using CuCl/2, 2′- bipyridine (bpy) as the catalyst system to afford the triblock copolymer, polystyrene-block-poly(1,10-dec- anediol/1,10-sebacate)-block-polystyrene (PS t-b-PSD- b-PSt). Molecular weight distribution and structure of the resulting triblock copolymer was confirmed by Waters 410 Gel permeation chromatography (GPC) and measurements of nuclear magnetic resonance (NMR) analysis.

关键词：缩聚聚合物结合酶 ATRP 嵌段共聚

An improved elastoplastic model for rocks and application to cyclic loading and unloading triaxial compression tests

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Acta Mechanica Sinica 2024年第8期40卷 179-193页

作者： Qiuxin Gu Qiang Zhang yapeng li Peinan Wu Guilei Han State Key Laboratory for Geomechanics and Deep Underground Engineering School of Mechanics and Civil EngineeringChina University of Mining and TechnologyXuzhou221116China North China Engineering Investigation Institute Shijiazhuang050021China

The recoverable strain of rock is completely classified as elastic strain in the conventional elastic-plastic theory,which often results in poor agreement between theoretical and experimental *** work proposes an improved elastoplastic model of rock materials considering the evolutions of crack deformation and elastic modulus to better characterize the nonlinear mechanical behavior of rock in the post-peak *** this model,the recoverable strain is assumed to be a combination of elastic and crack strain,and the constitutive relationship between crack strain and rock stress is *** on the proposed assumption,the evolutions of the mechanical parameters including strength parameters,elastic,plastic,and crack deformation parameters versus the plastic strain and confining stress were *** developed elastoplastic model was validated by comparing the theoretical values with the results of the triaxial cyclic loading and unloading *** theoretical calculation results show a good agreement with the laboratory test,which indicates that the improved elastoplastic model can effectively reflect the nonlinear mechanical behavior of the rock *** research results are expected to provide a valuable reference for further understanding the evolution of rock crack deformation.

关键词： Crack strain Elastic modulus deterioration Novel elastoplastic model Model validation

Chemoenzymatic synthesis amphiphilic H-shaped copolymer and its self-assembly behavior

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Science China Chemistry 2009年第12期52卷 2336-2341页

作者： ShuWei Wang Bao Zhang Peng Ai Ming Zhu Wei Wang ZhongPeng Sa liNa Ma yapeng li Alan G. MacDiarmid Institute of Jilin University Changchun 130012 China Department of Bioengineering College of Pharmacy Jilin University Changchun 130021 China

ABA triblock copolymers were synthesized by dihydroxyl-capped PEO initiated enzymatic ring-opening polymerization (eROP) of ε-CL in the presence of biocatalyst Novozyme 435. The chains ended with hydroxyl of block copolymers were modified by the esterification of 2,2-dichloro acetyl chloride (DCAC) to obtain the tetrafunctional macroinitiator, which was used in the ATRP of 4-vinylpyridine (4-VP). CuCl/HMTETA was used as the catalyst system in the ATRP of 4-VP to acquire the H-shaped block copolymers (PVP)2-b-PCL-b-PEG-b-PCL-b-(PVP)2. The H-shaped block copolymers were characterized by FTIR, NMR, and GPC. Copolymers with high molecular weights (M n = 46121 g/mol) and low polydispersities (M w/M n = 1.30) were prepared. Moreover, the morphology of the copolymer was examined with dynamic light scattering (DLS) and atomic force microscopy (AFM). Spherical micelles with a diameter of 70 nm in aqueous solution were obtained.

关键词： atom transfer radical polymerization (ATRP) enzymatic ring-opening polymerization (eROP) amphiphilic block copolymer

The rural economic development under the background of food security, resource allocation and regional coordination

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International Journal of Technology Management 2013年第12期 29-31页

作者： Bangxi li yapeng Wang College of Economics & Management Huazhong Agricultural University Wuhan Hubei 430070 China

From the background of new socialist countryside building, this paper proposes that the allocation of resources in rural areas is the organic combination of human resources in rural manpower on its possible configuration space, noting that effective human resource allocation in rural areas is of great significance to promote the moderately prosperous society building and to improve economic efficiency of human resources in rural areas and to increase farmers＇ income and so on ; Meanwhile, it analyzes the current situation and some problems of rural human resource allocation ; Finally, from the perspective of subject of human resources allocation in rural areas, it raises possible valid configuration path.

关键词： food security resource allocation regional coordination

Reflections on the management of agricultural economy in transition time of agricultural economy

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International Journal of Technology Management 2013年第12期 143-146页

作者： Bangxi li yapeng Wang College of Economics & Management Huazhong Agricultural University Wuhan Hubei 430070 China

In recent years, although farmers＇ income from agriculture is declining year by year, but the agricultural one is still the most important source of income. Factors determining the size of the total agricultural income are two sides： one is agricultural prices and the other is agricultural production. Obviously, because enhancements of China agricultural production capacity and several price increases of agricultural products, market saturation occurs in China＇ s major agricultural products and the price is close to or above the average level of international market. Simply relying on production increase and price hike has no longer satisfied growth needs of agricultural income.

关键词： management of agricultural economy transition

Present Situation and Development of Chinese Grain Food Safety

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International Journal of Technology Management 2013年第9期 10-12页

作者： Bangxi li yapeng Wang College of Economics & Management Huazhong Agricultural University Wuhan Hubei 430070 China

The recent outstanding issues,＂ puzzles of farmers, anxiety oflocal government and helplessness ofcentral government,＂ facing Chinese grain security, depend on the lack of national food security strategy. Therefore, we must reconstruct our national food security strategy with a cornerstone of an integrated productivity, the focus control of market regulation forces and the protection of sovereignty. By analyzing the status of integrated productivity, market regulation force and sovereign control, this essay proposes that we should change the concept from ＂ food production＂ to ＂foOd management＂, design the two systems of the interest coordination and the special safeguard, effectively improve the enthusiasm of the government＇ s undertaking work in grain-producing areas and farmers＇ farming work, firmly grasp the two initiatives of acquisition and processing of grain and operating inputs, and actively apply recommendations of the two regulators： food exports, processing and conversion.

关键词： Food security national strategy integrated productivity market regulation force

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形状记忆合金驱动的人工逼尿肌系统

华南理工大学学报（自然科学版） 2024年第6期52卷 73-80页

作者：李笑李亚鹏广东工业大学机电工程学院广东广州510006

针对神经源性、肌源性膀胱缺乏有效治疗手段的现状,从工程学角度提出了一种新的解决方案——人工逼尿肌系统。基于形状记忆合金(SMA)弹簧的形状记忆效应,设计了由无线能量传输模块、控制模块、反馈模块和执行模块组成的系统结构,旨在实... 详细信息

针对神经源性、肌源性膀胱缺乏有效治疗手段的现状,从工程学角度提出了一种新的解决方案——人工逼尿肌系统。基于形状记忆合金(SMA)弹簧的形状记忆效应,设计了由无线能量传输模块、控制模块、反馈模块和执行模块组成的系统结构,旨在实现符合人体尿动力学规律的辅助排尿。文中首先建立了人体膀胱的有限元模型,仿真分析了人体膀胱的储尿和辅助排尿过程,在仿真结果的基础上结合SMA弹簧的数学模型,对SMA弹簧致动器的结构参数进行了优化设计;其次,结合实验数据推导了SMA弹簧温度-自由高度方程;然后,结合热力学公式和弹簧数学模型推导了系统控制方程,并在此基础上提出了系统开环控制策略;最后,基于系统的反馈模块,设计了比例积分微分(PID)闭环控制策略,并搭建模拟实验平台研究了系统的尿流率特性。结果表明:系统原理可行,辅助排尿过程连续可控,在应对不同尿液容量时两种控制策略均能实现符合人体尿动力学规律的辅助排尿。文中结果可为设计适用于临床的人工逼尿肌系统提供指导,也可为其他以SMA弹簧作为致动器的植入装置的设计提供借鉴和参考。

关键词：人工逼尿肌形状记忆合金弹簧连续控制尿动力学