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On the notions of singular domination and(multi-)singular hyperbolicity

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Science China Mathematics 2020年第9期63卷 1721-1744页

作者： Sylvain Crovisier Adriana da Luz dawei Yang Jinhua Zhang Laboratoire de Mathematiques d'Orsay CNRSUniversite Paris-SudOrsay 91405France Beijing International Center for Mathematical Research Peking UniversityBeijing 100871China School of Mathematical Sciences Soochow UniversitySuzhou 215006China School of Mathematical Sciences Beihang UniversityBeijing 100191China

The properties of uniform hyperbolicity and dominated splitting have been introduced to study the stability of the dynamics of *** meets difficulties when trying to extend these definitions to vector fields and Shantao Liao has shown that it is more relevant to consider the linear Poincare flow rather than the tangent flow in order to study the properties of the *** this paper,we define the notion of singular domination,an analog of the dominated splitting for the linear Poincar´e flow which is robust under *** on this,we give a new definition of multi-singular hyperbolicity which is equivalent to the one recently introduced by Bonatti and da Luz(2017).The novelty of our definition is that it does not involve the blow-up of the singular set and the rescaling cocycle of the linear flows.

关键词： multi-singular hyperbolicity singular domination star vector field linear Poincar´e flow

Theoretical research on construction quality real-time monitoring and system integration of core rockfill dam

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Science China(Technological Sciences) 2009年第11期52卷 3406-3412页

作者： ZHONG DengHua CUI Bo LIU DongHai TONG dawei Department of Hydraulic and Hydroelectric Engineering School of Civil EngineeringTianjin UniversityTianjin 300072China

With the enlargement of core rockfill dam construction scale and the improvement of construction mechanization level, the traditional manual construction quality control method is now difficult to meet the quality and safety demands of modern dam construction, so automatic and real-time dam construction quality monitoring with high-techs is urgently needed. The paper makes theoretical research on construction quality real-time monitoring and system integration of core rockfill dam, proposes implementation method and integrated solution of construction quality real-time monitoring of core rockfill dam construction process, realizes refining, all-whether, entire-process and real-time control and analysis on key links of dam construction, and introduces the application of the construction quality real-time monitoring and system integration technology to a practical core rockfill dam project.

关键词： core rockfill dam construction quality real-time monitoring system integration

Hydrophilic adamantane derivatives engineered β-cyclodextrin-based self-assembly materials for highly efficient enrichment of glycopeptides

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Chinese Chemical Letters 2023年第3期34卷 283-287页

作者： Ping Li Zheng Li dawei Zhang Qiong Jia College of Chemistry Jilin UniversityChangchun 130012China Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education College of Life SciencesJilin UniversityChangchun 130012China

β-Cyclodextrin(β-CD) based materials have attracted great attention in the separation of hydrophilic glycopeptides due to the abundant hydroxyl groups in its exterior. However, the current materials based on β-CD generally has complex synthesis process and harsh experimental conditions, on the other hand,the interior cavity of β-CD is hydrophobic and is harmful to capture glycopeptides. Herein, a novel hydrophilic material based on β-CD was engineered via a self-assembly process utilizing L-cysteine(L-Cys)or glutathione(GSH) derived adamantane for highly efficient glycopeptide enrichment. It is the first attempt to make use of the hydrophobic interior cavity of β-CD for hydrophilic glycopeptide capture. Taking advantages of strong hydrophilicity and superparamagnetism, the as-prepared materials possess low detection limit, high selectively, and excellent reusability when employed to glycopeptide enrichment. In addition, the feasibility of the hydrophilic material based on β-CD was verified by enriching glycopeptides from human serum and saliva samples. This study provides a heuristic strategy for the application of β-CD-based self-assembly materials in the enrichment of glycopeptides. Importantly, this strategy certified a possible that the change of glycopeptide enrichment sites through host-guest interaction between β-CD and adamantane derivatives with different functional groups.

关键词： β-Cyclodextrin Hydrophilic Self-assembly Enrichment Glycopeptides

Friction of MoO_(3) Nanoflakes on Graphite Surface with an Ace-like Intercalation Layer

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Chemical Research in Chinese Universities 2022年第3期38卷 769-773页

作者： WEI dawei ZHANG Guangjie LU Xiaoquan QIU Xiaohui Tianjin Key Laboratory of Molecular Optoelectronic Department of ChemistrySchool of ScienceTianjin UniversityTianjin300072P.R.China CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing100190P.R.China Key Laboratory of Bioelectrochemistry&Environmental Analysis of Gansu Province College of Chemistry&Chemical EngineeringNorthwest Normal UniversityLanzhou730070P.R.China University of Chinese Academy of Sciences Beijing100049P.R.China

How water layer adsorbed on solid surface under ambient conditions affects the interfacial friction is a fundamental question for understanding the friction and lubrication phenomena in practical *** investigate the formation of ice-like(IL)water layers on the hydrophobic surface of graphite with partially covered MoO_(3)nanoflakes(NFs)using atomic force microscopy(AFM)based *** IL water layers are found surrounding the MoO_(3)NFs and also intercalated at the MoO_(3)/graphite interface,as proved by thickness measurements as well as local adhesion force and surface potential *** manipulations carried out on MoO_(3)NFs on graphite show that the presence of the IL water layers increases the frictional resistance of the *** the results on continuous and discontinuous IL water layers,we can identify the different sliding interfaces in the two *** increased friction for MoO_(3)NFs sliding on graphite with an intercalated water layer is attributed to the energy dissipation originated from the metastable nature of the IL layers.

关键词： Friction Ice-like water MoO_(3) Graphite

Finite element modeling of counter-roller spinning for large-sized aluminum alloy cylindrical parts

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Frontiers of Mechanical Engineering 2019年第3期14卷 351-357页

作者： dawei ZHANG Fan LI Shuaipeng LI Shengdun ZHAO School of Mechanical Engineering Xi'an Jiaotong University Xi'an 710049 China

Counter-roller spinning (CRS), where the mandrel is replaced by rollers, is an effective means of manufacturing large-sized, thin-walled, cylindrical parts with more than 2500 mm diameter. CRS is very complex because of multi-axis rotation, multi-local loading along the circumference, and radial-axial compound deformation. Analytical or experimental methods cannot fully understand CRS. Meanwhile, numerical simulation is an adequate approach to investigate CRS with comprehensive understanding and a low cost. Thus, a finite element (FE) model of CRS was developed with the FORGE code via meshing technology, material modeling, determining the friction condition, and so on. The local fine mesh moving with the roller is one of highlights of the model. The developed 3D-FE model was validated through a CRS experiment by using a tubular blank with a 720 mm outer diameter. The developed 3D-FE model of CRS can provide a basis for parameter optimization, process control, die design, and so on. The data on force and energy predicted by the 3D-FE model can offer reasonable suggestions for determining the main mechanical parameters of CRS machines and selecting the motors. With the predicted data, an all-electric servo-drive system/machine with distributed power was designed in this work for CRS with four pairs of rollers to manufacture a large-sized, thinwalled, cylindrical part with 6000 mm diameter.

关键词： large-sized cylindrical part counter-roller spinning aluminum alloy finite element method distributed power

BACNN: Multi-scale feature fusion-based bilinear attention convolutional neural network for wood NIR classification

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Journal of Forestry Research 2024年第4期35卷 202-214页

作者： Zihao Wan Hong Yang Jipan Xu Hongbo Mu dawei Qi College of Science Northeast Forestry UniversityHarbin 150040People’s Republic of China

Effective development and utilization of wood resources is *** modification research has become an integral dimension of wood science research,however,the similarities between modified wood and original wood render it challenging for accurate identification and classification using conventional image classification ***,the development of efficient and accurate wood classification techniques is *** paper presents a one-dimensional,convolutional neural network(i.e.,BACNN)that combines near-infrared spectroscopy and deep learning techniques to classify poplar,tung,and balsa woods,and PVA,nano-silica-sol and PVA-nano silica sol modified woods of *** results show that BACNN achieves an accuracy of 99.3%on the test set,higher than the 52.9%of the BP neural network and 98.7%of Support Vector Machine compared with traditional machine learning methods and deep learning based methods;it is also higher than the 97.6%of LeNet,98.7%of AlexNet and 99.1%of ***,the classification method proposed offers potential applications in wood classification,especially with homogeneous modified wood,and it also provides a basis for subsequent wood properties studies.

关键词： Wood classification Near infrared spectroscopy Bilinear network SE module Anti-noise algorithm

Electron-beam irradiation induced optical transmittance enhancement for Au/ITO and ITO/Au/ITO multilayer thin films

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Journal of Materials Science & Technology 2017年第10期33卷 1107-1112页

作者： Wenzuo Wei Ruijin Hong Jinxia Wang Chunxian Tao dawei Zhang Engineering Research Center of Optical Instrument and System Ministry of Education and Shanghai Key Lab of Modern Optical System University of Shanghai for Science and Technology Shanghai 200093 China

Electron beam（EB） irradiation experiments on Au/ITO and ITO/Au/ITO multilayer thin films are *** structure and the optical-electrical properties of the samples were investigated by X-ray diffraction,atomic force microscopy, four-point probe resistivity measurement system, and UV–vis-NIR double beam spectrometer, respectively. Those results show that the EB irradiation has the effects of improving the crystalline of samples, widening the optical band gap of both thin films, reducing the sheet resistance,and improving the transmittance of samples.

关键词： EB irradiation Multilayer thin films Structure Optical-electrical properties Transmittance

外源性碱性成纤维细胞生长因子促进大鼠创面愈合的机制

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中国组织工程研究 2025年第11期29卷 2243-2251页

作者：李振超杜喜玲韩志新牛大伟樊昌伟安阳市人民医院整形烧伤科河南省安阳市455000 鹤壁职业技术学院河南省鹤壁市458000

背景:深入揭示外源性碱性成纤维细胞生长因子促进创面愈合的分子机制。目的:探讨外源性碱性成纤维细胞生长因子对大鼠创面修复中巨噬细胞表型转换和肉芽再生的影响。方法:(1)体外细胞实验:分为正常对照组、低剂量碱性成纤维细胞生长因... 详细信息

背景:深入揭示外源性碱性成纤维细胞生长因子促进创面愈合的分子机制。目的:探讨外源性碱性成纤维细胞生长因子对大鼠创面修复中巨噬细胞表型转换和肉芽再生的影响。方法:(1)体外细胞实验:分为正常对照组、低剂量碱性成纤维细胞生长因子组、高剂量碱性成纤维细胞生长因子组以及碱性成纤维细胞生长因子+丙戊酸组,其中低、高剂量碱性成纤维细胞生长因子组细胞培养基中分别添加100,200μg/L碱性成纤维细胞生长因子,碱性成纤维细胞生长因子+丙戊酸组细胞培养基中添加200μg/L碱性成纤维细胞生长因子和20 mmol/L Notch1/Jagged1激动剂丙戊酸。通过EdU实验、划痕实验、小管生成实验检测碱性成纤维细胞生长因子对人脐静脉内皮细胞增殖、迁移和血管新生的影响。(2)体内动物实验:SD大鼠按照随机数字表法分为模型组、低剂量碱性成纤维细胞生长因子组、高剂量碱性成纤维细胞生长因子组以及碱性成纤维细胞生长因子+丙戊酸组,构建大鼠全层皮肤缺损开放性创面模型,其中低、高剂量碱性成纤维细胞生长因子组皮下注射100,200μg/L碱性成纤维细胞生长因子,碱性成纤维细胞生长因子+丙戊酸组大鼠皮下注射200μg/L碱性成纤维细胞生长因子的同时腹腔注射10 mg/kg丙戊酸。给药7,14 d检测大鼠创面的愈合率;TUNEL检测创面组织中的细胞凋亡情况;酶联免疫吸附实验检测大鼠血清中丙二醛、超氧化物歧化酶、肿瘤坏死因子α和白细胞介素10水平;免疫荧光检测创面组织中巨噬细胞的表型转换情况;免疫组化检测创面组织中增殖细胞核抗原、CD31和血管内皮生长因子的表达;Western blot法检测创面组织中Notch1、Jagged1的表达。结果与结论:(1)与正常对照组相比,碱性成纤维细胞生长因子能明显促进人脐静脉内皮细胞的增殖、迁移和血管新生,并且具有剂量依赖性;(2)与模型组相比,碱性成纤维细胞生长因子能明显促进创面的愈合,下调创面组织中的细胞凋亡率;降低大鼠血清中丙二醛和肿瘤坏死因子α水平,升高超氧化物歧化酶和白细胞介素10水平;促使创面组织中巨噬细胞向M2型转换,上调创面组织中增殖细胞核抗原、CD31和血管内皮生长因子的表达;抑制创面组织中Notch1、Jagged1的表达,并且均具有剂量依赖性。丙戊酸可部分逆转碱性成纤维细胞生长因子对创面愈合的促进作用。结果表明,碱性成纤维细胞生长因子能明显促进创面愈合与肉芽再生以及诱导巨噬细胞向M2型转换,这可能与调控Notch1/Jagged1信号有关。

关键词：碱性成纤维细胞生长因子全层皮肤缺损创面巨噬细胞表型转换肉芽再生 Notch1 Jagged1

Short-term effects of fire disturbance on CH4 emission from forested wetlands in the Xiaoxing’an Mountains, Northeast China

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Journal of Forestry Research 2019年第3期30卷 969-979页

作者： Han Gu Wenyu Zheng dawei Xu Changcheng Mu College of Architecture and Urban Planning Chongqing Jiaotong UniversityChongqing 40074People’s Republic of China Postdoctoral Program of Landscape Architecture Northeast Forestry UniversityHarbin 150040People’s Republic of China School of Forestry Northeast Forestry University Harbin 150040People’s Republic of China

Using static chamber gas chromatography, we determined the seasonal dynamics, controlling factors, and distribution patterns of forest swamp CH4 levels and related environmental factors (temperature, water level) after fire disturbance in the Xiaoxing’an Mountains. The results showed the following: during the growing season, the annual CH4 emission distribution ranged from - 0.001 ± 0.012 to 22.373 ± 3.650 mg m^-2 h^-1;mild fire caused the swamp CH4 emission flux of tussock, shrub, Alnus sibirica and birch swamp to increase by 56.0–524.7%;at low water levels, temperature had a significant influence on the swamp type, and the correlation between the methane emission flux and temperature was significantly strengthened;after a fire disturbance, methane emissions from all types of marsh were highest in summer and second highest in autumn, with a weak absorption in spring;and along the water environment gradient of the transition zone, the CH4 emission flux presented a decreasing trend in its spatial distribution pattern.

关键词： Xiaoxing’an Mountains Forest swamp CH4 emission Fire disturbance