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Exploring the Effect of Plasticity on the Phase Imaging of TM-AFM Through Molecular Dynamics Simulations

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Acta Mechanica Solida Sinica 2024年第2期37卷 297-304页

作者： Guolin Liu yu zeng Yaxin Chen Zheng Wei School of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing100029China

In the tapping-mode atomic force microscope(TM-AFM),the probe tip continuously taps the sample surface,which may cause plastic deformation of the sample and result in energy *** energy dissipation of the probe is closely related to the scanned phase *** quantify the energy dissipation due to plastic indentations of the sample,this study utilized a combination of molecular dynamics(MD)simulations and experiments on single-crystal copper samples,including multiple nano-indentation *** energy dissipation of the probe due to the plastic deformation of the sample was calculated by integrating the hysteresis curve of the indentation depth versus the force applied to the *** simulation results are in good agreement with the experimental *** sets of results have demonstrated that the plastic energy dissipation decreases as the number of indentations increases,and eventually the energy of the probe tends to *** equilibrium energy dissipation is associated with other dissipation ***,it was observed that,after hundreds of taps,the dissipated energy of plastic deformation could be ignored,implying that the scanned image may not reflect the plasticity information of the sample after multiple taps of the probe on the sample surface for scanning.

关键词： Atomic force microscopy Force-distance curves Nano-indentations Plasticity Molecular dynamics

Deterministic learning-based neural output-feedback control for a class of nonlinear sampled-data systems

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Science China(Information Sciences) 2024年第09期67卷 164-183页

作者： yu zeng Fukai ZHANG Tianrui CHEN Cong WANG School of Automation Science and Engineering South China University of Technology School of Control Science and Engineering Shandong University

This study investigates the deterministic learning(DL)-based output-feedback neural control for a class of nonlinear sampled-data systems with prescribed performance(PP). Specifically, first, a sampleddata observer is employed to estimate the unavailable system states for the Euler discretization model of the transformed system dynamics. Then, based on the observations and backstepping method, a discrete neural network(NN) controller is constructed to ensure system stability and achieve the desired tracking performance. The noncausal problem encountered during the controller deduction process is resolved using a command filter. Moreover, the regression characteristics of the NN input signals are demonstrated with the observed states. This ensures that the radial basis function NN, based on DL theory, meets the partial persistent excitation condition. Subsequently, a class of discrete linear time-varying systems is proven to be exponentially stable, achieving partial convergence of neural weights to their optimal/actual values. Consequently, accurate modeling of unknown closed-loop dynamics is achieved along the system trajectory from the output-feedback control. Finally, a knowledge-based controller is developed using the modeling *** controller not only enhances the control performance but also ensures the PP of the tracking error. The effectiveness of the scheme is illustrated through simulation results.

关键词： adaptive neural control deterministic learning neural networks nonlinear sampled-data systems predefined performance

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Printed Biosensors for the Detection of Alzheimer's Disease Based on Blood Biomarkers

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Journal of Analysis and Testing 2024年第2期 133-142页

作者： yu zeng Zhen Huang Yibiao Liu Tailin Xu Longgang Central Hospital of Shenzhen School of Biomedical Engineering Shenzhen University

Alzheimer's disease(AD) is a chronic neurodegenerative disorder, and early diagnosis plays a crucial role in its prevention and treatment. In recent years, blood-based biomarkers for early AD diagnosis have gained attention due to their non-invasiveness and minimal adverse reactions, which make them an attractive approach. Since the onset of the COVID-19 pandemic, visiting large medical examination centers for blood tests has become increasingly challenging. The trend is shifting towards community or home-based sampling, which relies on the development and application of portable, miniaturized, and highly sensitive sensors. Among the various sensors used for detecting blood biomarkers in AD, printed sensors demonstrate great potential in AD blood biomarker detection due to their ease of miniaturization, scalability for mass production, and compatibility with various detection methods. In this review, we focus on discussing the application of printed sensors in the analysis of blood biomarkers for AD. We also explore the challenges faced by printed sensors in early diagnosis based on AD blood biomarkers and propose potential solutions to address these challenges.

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Temperature-Induced Unfolding Pathway of Staphylococcal Enterotoxin B:Insights from Circular Dichroism and Molecular Dynamics Simulation

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食品科学 2024年第18期45卷 55-76页

作者： LIU Ji ZHANG Shiyu zeng yu DENG Yi Institute of Qinghai-Tibetan Plateau Southwest Minzu UniversityChengdu 610041China College of Food Sciences and Technology Southwest Minzu UniversityChengdu 610041China Wuliangye Group Co.Ltd. Yibin 644000China

In this study,circular dichroism(CD)and molecular dynamics(MD)simulation were used to investigate the thermal unfolding pathway of staphylococcal enterotoxin B(SEB)at temperatures of 298–371 and 298–500 K,and the relationship between the experimental and simulation results were *** computational findings on the secondary structure of SEB showed that at room temperature,the CD spectroscopic results were highly consistent with the MD ***,under heating conditions,the changing trends of helix,sheet and random coil obtained by CD spectral fitting were highly consistent with those obtained by *** order to gain a deeper understanding of the thermal stability mechanism of SEB,the MD trajectories were analyzed in terms of root mean square deviation(RMSD),secondary structure assignment(SSA),radius of gyration(R_(g)),free energy surfaces(FES),solvent-accessible surface area(SASA),hydrogen bonds and salt *** results showed that at low heating temperature,domain Ⅰ without loops(omitting the mobile loop region)mainly relied on hydrophobic interaction to maintain its thermal stability,whereas the thermal stability of domain Ⅱ was mainly controlled by salt bridges and hydrogen *** high heating temperature conditions,the hydrophobic interactions in domain Ⅰ without loops were destroyed and the secondary structure was almost completely lost,while domain Ⅱ could still rely on salt bridges as molecular staples to barely maintain the stability of the secondary *** results help us to understand the thermodynamic and kinetic mechanisms that maintain the thermal stability of SEB at the molecular level,and provide a direction for establishing safer and more effective food sterilization processes.

关键词： staphylococcal enterotoxin B circular dichroism molecular dynamics simulations temperature-induced unfolding

GATIS score for predicting the prognosis of rectal neuroendocrine neoplasms:A Chinese multicenter study of 12-year experience

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World Journal of Gastroenterology 2024年第28期30卷 3403-3417页

作者： Xin-yu zeng Ming Zhong Guo-Le Lin Cheng-Guo Li Wei-Zhong Jiang Wei Zhang Li-Jian Xia Mao-Jun Di Hong-Xue Wu Xiao-Feng Liao yue-Ming Sun Min-Hao yu Kai-Xiong Tao Yong Li Rui Zhang Peng Zhang Department of Gastrointestinal Surgery Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430074Hubei ProvinceChina Department of Gastrointestinal Surgery Renji HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai 200127China Department of General Surgery Peking Union Medical College HospitalPeking Union Medical CollegeBeijing 100730China Department of Colorectal Surgery Fujian Medical UniversityFuzhou 350401Fujian ProvinceChina Department of Colorectal Surgery Changhai HospitalShanghai 200433China Department of Gastrointestinal Surgery The First Affiliated Hospital of Shandong First Medical UniversityJinan 250118Shandong ProvinceChina Department of Gastrointestinal Surgery Taihe HospitalHubei University of MedicineShiyan 442099Hubei ProvinceChina Department of Gastrointestinal Surgery I Section Renmin Hospital of Wuhan UniversityWuhan 430060Hubei ProvinceChina Department of General Surgery Xiangyang Central HospitalAffiliated Hospital of Hubei University of Arts and ScienceXiangyang 441021Hubei ProvinceChina Department of Colorectal Surgery Jiangsu Province HospitalNanjing Medical UniversityNanjing 210029Jiangsu ProvinceChina Department of Gastrointestinal Surgery School of MedicineShanghai Jiao Tong UniversityShanghai 200127China Department of General Surgery Guangdong Provincial People’s HospitalGuangdong Academy of Medical SciencesGuangzhou 510080Guangdong ProvinceChina Department of Colorectal Surgery Liaoning Cancer HospitalShenyang 110042Liaoning ProvinceChina

BACKGROUND There is currently a shortage of accurate,efficient,and precise predictive instruments for rectal neuroendocrine neoplasms(NENs).AIM To develop a predictive model for individuals with rectal NENs(R-NENs)using data from a large *** Data from patients with primary R-NENs were retrospectively collected from 17 large-scale referral medical centers in *** forest and Cox proportional hazard models were used to identify the risk factors for overall survival and progression-free survival,and two nomograms were *** A total of 1408 patients with R-NENs were *** grade,T stage,tumor size,age,and a prognostic nutritional index were important risk factors for *** GATIS score was calculated based on these five *** overall survival prediction,the respective C-indexes in the training set were 0.915(95%confidence interval:0.866-0.964)for overall survival prediction and 0.908(95%confidence interval:0.872-0.944)for progression-free survival *** to decision curve analysis,net benefit of the GATIS score was higher than that of a single *** time-dependent area under the receiver operating characteristic curve showed that the predictive power of the GATIS score was higher than that of the TNM stage and pathological grade at all time *** The GATIS score had a good predictive effect on the prognosis of patients with R-NENs,with efficacy superior to that of the World Health Organization grade and TNM stage.

关键词： Rectal neuroendocrine neoplasm Nomogram Random forest Prognosis Overall survival Progression-free survival

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新基建专项债的就业效应与空间外溢性

世界经济 2024年第2期47卷 152-173页

作者：刘楠楠曾宇西南财经大学财政税务学院

本文手工收集整理2015-2021年专项债和新基建项目等数据,通过双重差分识别策略和双重差分空间杜宾模型,探讨新基建专项债对劳动力市场的就业效应及其空间外溢性。研究发现:(1)新基建专项债对就业具有乘数效应,不仅能够增加专项债指定投... 详细信息

本文手工收集整理2015-2021年专项债和新基建项目等数据,通过双重差分识别策略和双重差分空间杜宾模型,探讨新基建专项债对劳动力市场的就业效应及其空间外溢性。研究发现:(1)新基建专项债对就业具有乘数效应,不仅能够增加专项债指定投向领域3.49%的就业,还通过扩散效应带动非指定投向领域8.34%的地区就业;(2)与传统基建专项债不同,新基建专项债能够产生显著的行业和岗位替代效应,有助于优化劳动力市场的就业结构;(3)新基建专项债的就业结构效应具有正向溢出特征,表现为本地区高技能劳动力流入和低技能劳动力流出。本文对于促进劳动力市场格局转变、减少地区间摩擦性失业有政策参考价值。

关键词：新基建专项债就业效应空间外溢性

战国秦汉时期西南夷地区的镀锡铜器及相关问题

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考古 2024年第2期 78-88,F0002页

作者：曾宇杨硕李映福四川大学考古文博学院成都市610200 四川省文物考古研究院成都市610200

西南夷地区镀锡铜器的年代在战国中晚期至东汉早期,采用热镀锡技术,为冉駹、徙、筰、滇、靡莫等土著族群使用。同类技术在巴蜀地区的年代更早,且存续长、自成体系,应为西南夷地区镀锡技术的源头。荥经一带与徙、筰等族群杂处的蜀人,应... 详细信息

西南夷地区镀锡铜器的年代在战国中晚期至东汉早期,采用热镀锡技术,为冉駹、徙、筰、滇、靡莫等土著族群使用。同类技术在巴蜀地区的年代更早,且存续长、自成体系,应为西南夷地区镀锡技术的源头。荥经一带与徙、筰等族群杂处的蜀人,应为传播镀锡铜器及技术的中介,传播路线与汉武帝时期西夷道基本重合。

关键词：战国秦汉时期西南夷地区镀锡铜器技术来源巴蜀地区

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小流域海绵城市系统化方案的编制及思考

中国给水排水 2024年第4期40卷 52-58页

作者：俞露曾思育汤钟张亮清华大学环境学院北京100084 深圳市城市规划设计研究院股份有限公司广东深圳518028

随着海绵城市建设从规划阶段向实施阶段的过渡,建设思路也由单一海绵项目发展为片区整体解决方案。小流域海绵城市系统化方案采用系统化的思维,对现有海绵规划设计进行优化和统筹,可转变规划设计思维,按照海绵城市建设的总体要求,统筹... 详细信息

随着海绵城市建设从规划阶段向实施阶段的过渡,建设思路也由单一海绵项目发展为片区整体解决方案。小流域海绵城市系统化方案采用系统化的思维,对现有海绵规划设计进行优化和统筹,可转变规划设计思维,按照海绵城市建设的总体要求,统筹安排各项建设任务;量化分析建设任务的工程绩效和对规划目标的贡献程度,评估方案的可行性和有效性;深化规划的落实和设计的统筹,明确工程措施与海绵绩效的关系,整合优化海绵建设任务,提高工程的实施效率和效果。以某小流域为例,针对该流域的重点问题,提出了自然本底保护、水环境治理和水安全提升三方面的海绵建设策略,并通过模型评估等技术手段,对方案的实施效果进行了量化评估。该研究成果可为类似小流域海绵城市系统化方案编制提供参考。

关键词：海绵城市系统化方案片区达标小流域水力模型

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聚合物微胶囊中再生剂对沥青胶浆自修复性能的影响研究

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山西建筑 2024年第8期50卷 105-110页

作者：曾宇青海省湟源公路总段青海西宁810000

研究了葵花籽油海藻酸钙微胶囊在沥青胶浆中的自修复效果。通过对微胶囊形态、物理、热学和力学性能进行评价,并考察了微胶囊油含量以及自修复温度对沥青胶浆自修复性能的影响。实验结果表明,微胶囊能够在混合和压实过程中保持完整,在... 详细信息

研究了葵花籽油海藻酸钙微胶囊在沥青胶浆中的自修复效果。通过对微胶囊形态、物理、热学和力学性能进行评价,并考察了微胶囊油含量以及自修复温度对沥青胶浆自修复性能的影响。实验结果表明,微胶囊能够在混合和压实过程中保持完整,在沥青胶浆遭受机械载荷导致裂缝时释放出油,有效实现自我修复。含有微胶囊的沥青胶浆样品显示出更高水平的自修复能力,这与无微胶囊样品相比有显著差异。微胶囊的含油量和温度是影响自修复水平的关键因素。

关键词：沥青自修复微胶囊海藻酸钙葵花籽油

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