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Integrating Main-Chain and Side-Chain Engineering in Polymers for Enhanced Photocatalytic Hydrogen Production
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作者 TIAN Changhao LIU Xueyan +4 位作者 YU Miaojie WU Yongzhen CHE Yu ZHANG Weiwei ZHU Weihong 《功能高分子学报》 北大核心 2025年第3期216-227,共12页
Traditional polymeric photocatalysts are typically constructed using aromatic building blocks to enhanceπ-conjugation.However,their inherent hydrophobicity and rigid structure lead to poor dispersibility in aqueous s... Traditional polymeric photocatalysts are typically constructed using aromatic building blocks to enhanceπ-conjugation.However,their inherent hydrophobicity and rigid structure lead to poor dispersibility in aqueous solutions,resulting in significant optical losses and exciton recombination.In this study,two series of six novel polymer photocatalysts(FLUSO,FLUSO-PEG10,FLUSO-PEG30;CPDTSO,CPDTSO-PEG10,CPDTSO-PEG30)are designed and synthesized by incorporating the hydrophilic,non-conjugated polyethylene glycol(PEG)chain,into both the main and side chains of polymers.By precisely optimizing the ratio of hydrophilic PEG segments,the water dispersibility is significantly improved while the light absorption capability of the polymer photocatalysts is well maintained.The experimental results confirm that the optimized FLUSO-PEG10 exhibits excellent photocatalytic hydrogen evolution rate,reaching up to 33.9 mmol/(g·h),which is nearly three times higher than that of fullyπ-conjugated counterparts.Water contact angles and particle size analyses reveal that incorporating non-conjugated segments into the main chains enhances the capacitance of the polymer/water interface and reduces particle aggregation,leading to improved photocatalyst dispersion and enhanced charge generation. 展开更多
关键词 organic semiconductor polymer photocatalyst main-chain engineering side-chain engineering photocatalytic hydrogen evolution
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Enhanced Piezoelectric Properties of (1-x)(0.8PZT-0.2PZN)-xBZT Ceramics via Phase Boundary and Domain Engineering
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作者 CHEN Xiangjie LI Ling +2 位作者 LEI Tianfu WANG Jiajia WANG Yaojin 《无机材料学报》 北大核心 2025年第6期729-734,共6页
Pb(Zr,Ti)O_(3)-Pb(Zn_(1/3)Nb_(2/3))O_(3) (PZT-PZN) based ceramics, as important piezoelectric materials, have a wide range of applications in fields such as sensors and actuators, thus the optimization of their piezoe... Pb(Zr,Ti)O_(3)-Pb(Zn_(1/3)Nb_(2/3))O_(3) (PZT-PZN) based ceramics, as important piezoelectric materials, have a wide range of applications in fields such as sensors and actuators, thus the optimization of their piezoelectric properties has been a hot research topic. This study investigated the effects of phase boundary engineering and domain engineering on (1-x)[0.8Pb(Zr_(0.5)Ti_(0.5))O_(3)-0.2Pb(Zn_(1/3)Nb_(2/3))O_(3)]-xBi(Zn_(0.5)Ti_(0.5))O_(3) ((1-x)(0.8PZT-0.2PZN)- xBZT) ceramic to obtain excellent piezoelectric properties. The crystal phase structure and microstructure of ceramic samples were characterized. The results showed that all samples had a pure perovskite structure, and the addition of BZT gradually increased the grain size. The addition of BZT caused a phase transition in ceramic samples from the morphotropic phase boundary (MPB) towards the tetragonal phase region, which is crucial for optimizing piezoelectric properties. By adjusting content of BZT and precisely controlling position of the phase boundary, the piezoelectric performance can be optimized. Domain structure is one of the key factors affecting piezoelectric performance. By using domain engineering techniques to optimize grain size and domain size, piezoelectric properties of ceramic samples have been significantly improved. Specifically, excellent piezoelectric properties (piezoelectric constant d_(33)=320 pC/N, electromechanical coupling factor kp=0.44) were obtained simultaneously for x=0.08. Based on experimental results and theoretical analysis, influence mechanisms of phase boundary engineering and domain engineering on piezoelectric properties were explored. The study shows that addition of BZT not only promotes grain growth, but also optimizes the domain structure, enabling the polarization reversal process easier, thereby improving piezoelectric properties. These research results not only provide new ideas for the design of high-performance piezoelectric ceramics, but also lay a theoretical foundation for development of related electronic devices. 展开更多
关键词 phase boundary 0.8PZT-0.2PZN domain engineering piezoelectric property
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Multi-objective optimization of microwave power transmission system architecture with engineering consideration
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作者 DONG Shiwei SHINOHARA Naoki 《中国空间科学技术(中英文)》 北大核心 2025年第4期114-122,共9页
In the last decade,space solar power satellites(SSPSs)have been conceived to support net-zero carbon emissions and have attracted considerable attention.Electric energy is transmitted to the ground via a microwave pow... In the last decade,space solar power satellites(SSPSs)have been conceived to support net-zero carbon emissions and have attracted considerable attention.Electric energy is transmitted to the ground via a microwave power beam,a technology known as microwave power transmission(MPT).Due to the vast transmission distance of tens of thousands of kilometers,the power transmitting antenna array must span up to 1 kilometer in diameter.At the same time,the size of the rectifying array on the ground should extend over a few kilometers.This makes the MPT system of SSPSs significantly larger than the existing aerospace engineering system.To design and operate a rational MPT system,comprehensive optimization is required.Taking the space MPT system engineering into consideration,a novel multi-objective optimization function is proposed and further analyzed.The multi-objective optimization problem is modeled mathematically.Beam collection efficiency(BCE)is the primary factor,followed by the thermal management capability.Some tapers,designed to solve the conflict between BCE and the thermal problem,are reviewed.In addition to these two factors,rectenna design complexity is included as a functional factor in the optimization objective.Weight coefficients are assigned to these factors to prioritize them.Radiating planar arrays with different aperture illumination fields are studied,and their performances are compared using the multi-objective optimization function.Transmitting array size,rectifying array size,transmission distance,and transmitted power remaine constant in various cases,ensuring fair comparisons.The analysis results show that the proposed optimization function is effective in optimizing and selecting the MPT system architecture.It is also noted that the multi-objective optimization function can be expanded to include other factors in the future. 展开更多
关键词 space solar power satellite(SSPS) microwave power transmission(MPT) multi-objective function beam collection efficiency(BCE) system engineering
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A fast-running engineering tool for assessing structural vulnerability to blast loading
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作者 Carlo Crispino Salvatore Annunziata +2 位作者 Alberto Contini Luca Lomazzi Andrea Manes 《Defence Technology(防务技术)》 2025年第4期244-254,共11页
Assessing the vulnerability of a platform is crucial in its design.In fact,the results obtained from vulnerability analyses provide valuable information,leading to precise design choices or corrective solutions that e... Assessing the vulnerability of a platform is crucial in its design.In fact,the results obtained from vulnerability analyses provide valuable information,leading to precise design choices or corrective solutions that enhance the platform's chances of surviving different scenarios.Such scenarios can involve various types of threats that can affect the platform's survivability.Among such,blast waves impacting the platform's structure represent critical conditions that have not yet been studied in detail.That is,frameworks for vulnerability assessment that can deal with blast loading have not been presented yet.In this context,this work presents a fast-running engineering tool that can quantify the risk that a structure fails when it is subjected to blast loading from the detonation of high explosive-driven threats detonating at various distances from the structure itself.The tool has been implemented in an in-house software that calculates vulnerability to various impacting objects,and its capabilities have been shown through a simplified,yet realistic,case study.The novelty of this research lies in the development of an integrated computational environment capable of calculating the platform's vulnerability to blast waves,without the need for running expensive finite element simulations.In fact,the proposed tool is fully based on analytical models integrated with a probabilistic approach for vulnerability calculation. 展开更多
关键词 VULNERABILITY Blast loading Probabilistic assessment Analytical models Fast-running engineering tool
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Intelligent phase picking of microseismic signals based on ResUNet in underground engineering
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作者 OU Li-yuan HUANG Lin-qi +3 位作者 ZHAO Yun-ge WANG Zhao-wei SHEN Hui-ming LI Xi-bing 《Journal of Central South University》 2025年第9期3314-3335,共22页
With the continuous expansion of deep underground engineering and the growing demand for safety monitoring,microseismic monitoring has become a core method for early warning of rock mass fracture and engineering stabi... With the continuous expansion of deep underground engineering and the growing demand for safety monitoring,microseismic monitoring has become a core method for early warning of rock mass fracture and engineering stability assessment.To address problems in existing methods,such as low data processing efficiency and poor phase recognition accuracy under low signal-to-noise ratio(SNR)conditions in complex geological environments,this study proposes an intelligent phase picking model based on ResUNet.The model integrates the residual learning mechanism of ResNet with the multi-scale feature extraction capability of UNet,effectively mitigating the vanishing gradient problem in deep networks.It also achieves cross-layer fusion of shallow detail features and deep semantic features through skip connections in the encoder-decoder structure.Compared with traditional short-time average/long-time average(STA/LTA)algorithms and advanced neural network models such as PhaseNet and EQTransformer,ResUNet shows superior performance in picking P-and S-wave phases.The model was trained on 400000 labeled microseismic signals from the Stanford earthquake dataset(STEAD)and was successfully applied to the Shizhuyuan polymetallic mine in Hunan Province,China.The results demonstrate that ResUNet achieves high picking accuracy and robustness in complex geological conditions,offering reliable technical support for early warning of disasters such as rockburst in deep underground engineering. 展开更多
关键词 underground engineering microseismic monitoring phase picking deep learning ResUNet architecture rock fracture early warning
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Engineering Cells and Tissue for Studying Development and Disease
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作者 Leo Q.Wan 《医用生物力学》 EI CAS CSCD 北大核心 2019年第A01期37-37,共1页
Cell and Tissue Engineering provides exciting opportunities for studying development and Disease.In this talk,we will focus on cell chirality,also known as handedness and left-right(LR)asymmetry,which is an intrinsic ... Cell and Tissue Engineering provides exciting opportunities for studying development and Disease.In this talk,we will focus on cell chirality,also known as handedness and left-right(LR)asymmetry,which is an intrinsic capability of the cell telling left from right(1)The development of the vertebrate body plan with left-right asymmetry requires the emerging chiral morphogenesis at multicellular levels at specific embryonic stages.Changes in orientation of the LR axis due to genetic or environmental factors can lead to malformations and disease.However,the concept of cell chirality has never studied in detail until the recent development of novel engineering tools[2-3].We demonstrate that the cultivation of cells on micropatterned 2D surfaces and in 3D graded hydrogels reveals an intrinsic cellular LR asymmetry,which is dependent of cell phenotype and actin cytoskeleton.With these new tools,we examine the role of cell chirality on the embryonic development of cardiac LR asymmetry [4] as well as the barrier function of endothelium layers [5].We find that Protein Kinase C(PKC)activation reverses the inherent chirality from clockwise to counter clockwise in engineering systems [4-5].Interestingly,activation of PKC signaling reverses the directional bias of chick cardiac C-looping [4].Mediating endothelial cell chirality can regulate the permeability of endothelial layers[5].Overall,our results strongly suggest critical roles of cell chirality in cardiovascular development and disease. 展开更多
关键词 engineering CELLS tissue for STUDYING DEVELOPMENT DISEASE
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Defect engineering of carbon-based electrocatalysts for the CO_(2)reduction reaction:A review 被引量:2
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作者 LU Yan-kun CHENG Bai-xue +1 位作者 ZHAN Hao-yu ZHOU Peng 《新型炭材料(中英文)》 SCIE EI CAS CSCD 北大核心 2024年第1期17-41,共25页
Electrocatalytic carbon dioxide(CO_(2))reduction is an important way to achieve carbon neutrality by converting CO_(2)in-to high-value-added chemicals using electric energy.Carbon-based materials are widely used in va... Electrocatalytic carbon dioxide(CO_(2))reduction is an important way to achieve carbon neutrality by converting CO_(2)in-to high-value-added chemicals using electric energy.Carbon-based materials are widely used in various electrochemical reactions,including electrocatalytic CO_(2)reduction,due to their low cost and high activity.In recent years,defect engineering has attracted wide attention by constructing asymmetric defect centers in the materials,which can optimize the physicochemical properties of the mater-ial and improve its electrocatalytic activity.This review summarizes the types,methods of formation and defect characterization tech-niques of defective carbon-based materials.The advantages of defect engineering and the advantages and disadvantages of various defect formation methods and characterization techniques are also evaluated.Finally,the challenges of using defective carbon-based materials in electrocatalytic CO_(2)reduction are investigated and opportunities for their use are discussed.It is believed that this re-view will provide suggestions and guidance for developing defective carbon-based materials for CO_(2)reduction. 展开更多
关键词 Defect engineering Carbon-based materials ELECTROCATALYSIS CO_(2)reduction
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Data-driven modeling on anisotropic mechanical behavior of brain tissue with internal pressure
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作者 Zhiyuan Tang Yu Wang +3 位作者 Khalil I.Elkhodary Zefeng Yu Shan Tang Dan Peng 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期55-65,共11页
Brain tissue is one of the softest parts of the human body,composed of white matter and grey matter.The mechanical behavior of the brain tissue plays an essential role in regulating brain morphology and brain function... Brain tissue is one of the softest parts of the human body,composed of white matter and grey matter.The mechanical behavior of the brain tissue plays an essential role in regulating brain morphology and brain function.Besides,traumatic brain injury(TBI)and various brain diseases are also greatly influenced by the brain's mechanical properties.Whether white matter or grey matter,brain tissue contains multiscale structures composed of neurons,glial cells,fibers,blood vessels,etc.,each with different mechanical properties.As such,brain tissue exhibits complex mechanical behavior,usually with strong nonlinearity,heterogeneity,and directional dependence.Building a constitutive law for multiscale brain tissue using traditional function-based approaches can be very challenging.Instead,this paper proposes a data-driven approach to establish the desired mechanical model of brain tissue.We focus on blood vessels with internal pressure embedded in a white or grey matter matrix material to demonstrate our approach.The matrix is described by an isotropic or anisotropic nonlinear elastic model.A representative unit cell(RUC)with blood vessels is built,which is used to generate the stress-strain data under different internal blood pressure and various proportional displacement loading paths.The generated stress-strain data is then used to train a mechanical law using artificial neural networks to predict the macroscopic mechanical response of brain tissue under different internal pressures.Finally,the trained material model is implemented into finite element software to predict the mechanical behavior of a whole brain under intracranial pressure and distributed body forces.Compared with a direct numerical simulation that employs a reference material model,our proposed approach greatly reduces the computational cost and improves modeling efficiency.The predictions made by our trained model demonstrate sufficient accuracy.Specifically,we find that the level of internal blood pressure can greatly influence stress distribution and determine the possible related damage behaviors. 展开更多
关键词 Data driven Constitutive law ANISOTROPY Brain tissue Internal pressure
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Interface engineering of FAPbI_(3) for passivating defects and improving stability with lead chalcogenides
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作者 LI Yun-hao FENG Xiang-xiang +3 位作者 LONG Meng-qiu CAI Meng-qiu YANG Jun-liang LIU Biao 《Journal of Central South University》 CSCD 2024年第12期4625-4637,共13页
Interface engineering is widely employed to enhance the performance of formamidinium lead triiodide(FAPbI_(3))perovskite solar cells.In this study,six different FAPbI_(3)/PbX(X=S,Se and Te)heterostructures are constru... Interface engineering is widely employed to enhance the performance of formamidinium lead triiodide(FAPbI_(3))perovskite solar cells.In this study,six different FAPbI_(3)/PbX(X=S,Se and Te)heterostructures are constructed,including the PbI interface and I interface perovskite.In addition,the lead vacancies(V-Pb)and iodine vacancies(V-I)are designed at the perovskite interface.The results show that the PbI interface is more stable than I interface in the heterostructures.The PbX covering layer on the surface of the FAPbI_(3) perovskite stabilizes the perovskite octahedral structure by interface interactions and charge reconstruction that are beneficial to passivate perovskite interface defects and inhibit the phase transition.It shows that the PbTe covering layer exhibits the best passivation effect for lead vacancy defects,while PbS covering layer shows the best passivation effect for iodine vacancy defects.Additionally,appropriate structural stress can strengthen the thermal stability of defective perovskite.This work reveals the FAPbI_(3)/PbX interface engineering,and offers new insights into effectively passivating defects and improving the stability of FAPbI_(3). 展开更多
关键词 interface engineering FAPbI_(3) PBX PSCs STABILITY
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新工科背景下金属材料工程实践教学改革探索 被引量:4
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作者 孙瑞雪 王兆波 刘欣 《实验室研究与探索》 北大核心 2025年第3期170-173,共4页
为了满足新工科建设对金属材料工程专业人才培养的要求,构建了以培养学生综合实践能力为核心的特色实践教学新模式。提出了深化产教融合,以赛促教、以赛促学,打造行走的“思政大课堂”,构建多元化的实践教学综合考评和反馈机制的新思路... 为了满足新工科建设对金属材料工程专业人才培养的要求,构建了以培养学生综合实践能力为核心的特色实践教学新模式。提出了深化产教融合,以赛促教、以赛促学,打造行走的“思政大课堂”,构建多元化的实践教学综合考评和反馈机制的新思路。实践表明,依托教科产融合基地,大大丰富了实践教学内容和教学形式,赛教融合助力了实践教学改革和学生综合创新能力的提升。通过挖掘实践教学所在企业或所在地的思政资源,让学生在实践教学过程中的思政教育落在实处。建立了基于能力和素质目标的多元化实践教学考评体系,有效提升了学生的创新能力、实践能力和工程素养。 展开更多
关键词 新工科 金属材料工程 实践教学 人才培养
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新工科背景下地方本科高校化工类专业人才培养的现实困境与实践路径 被引量:6
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作者 王慧 李少梅 王海宾 《教育理论与实践》 北大核心 2025年第9期18-21,共4页
新工科背景下,社会产业对创新工程人才的需求急速攀升。随着“绿色化工”“智能化工”的兴起,地方本科高校化工类专业人才培养普遍存在人才培养目标科学性不够、课程体系设置不够全面、教师工程实践经验不足、实践教学环节薄弱、人才质... 新工科背景下,社会产业对创新工程人才的需求急速攀升。随着“绿色化工”“智能化工”的兴起,地方本科高校化工类专业人才培养普遍存在人才培养目标科学性不够、课程体系设置不够全面、教师工程实践经验不足、实践教学环节薄弱、人才质量保障体系不够健全的现实困境。推动地方高校化工类专业人才培养建设和发展,需要明确与产业需求相统一的人才培养目标,构建解决复杂工程问题的大化工课程体系,建设具备丰富工程实践经验的“双师型”教师队伍,搭建能够提高学生动手能力的实践教学体系,完善化工人才培养保障体系。 展开更多
关键词 新工科 地方本科高校 化工类专业 人才培养
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基于GEE平台多源遥感数据的海南岛红树林碳储量估算
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作者 李尉尉 薛志泳 +1 位作者 朱建华 田震 《自然资源遥感》 北大核心 2025年第2期220-227,共8页
碳储量变化是碳库功能的一个重要指标,有效准确评估碳储量对区域碳循环和碳源/汇研究、减缓气候变化和维持区域可持续发展具有重要意义。该文基于多时序遥感影像数据(Sentinel-1、Sentinel-2)和谷歌地球引擎(Google Earth Engine, GEE)... 碳储量变化是碳库功能的一个重要指标,有效准确评估碳储量对区域碳循环和碳源/汇研究、减缓气候变化和维持区域可持续发展具有重要意义。该文基于多时序遥感影像数据(Sentinel-1、Sentinel-2)和谷歌地球引擎(Google Earth Engine, GEE)云计算平台,匹配ICESat-2植被冠层的光子点数据反演红树林树高,通过大范围尺度的红树林“树高-生物量”模型反演生物量,最终得到海南岛红树林树高、地上生物量和碳储量估算结果,从而分析其分布及变化情况。结果显示:海南岛红树林2016年、2019年和2022年平均高度分别为6.99 m, 7.26 m和7.71 m,其中各区域红树林树高整体均呈上升趋势;2016年、2019年和2022年海南岛红树林地上生物量总量分别为400 939.48 t, 411 928.64 t和458 759.02 t,平均地上生物量分别为110.23 t/hm^(2),114.61 t/hm^(2)和120.02 t/hm^(2),海南岛东北部的东寨港和八门湾区域地上生物量占总量的80%;红树林植被碳储量的增长率在1%~4.45%之间,其中东寨港、八门湾的红树林植被碳储量增长率最大,分别为4.45%和3.17%。研究成果可为大范围尺度红树林碳储量核算提供基础数据和方法参考,作为海南岛红树林管理和保护的重要参数数据。 展开更多
关键词 红树林 碳储量 生物量 Google Earth Engine 海南岛
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关节镜下组织工程支架修复软骨损伤 被引量:1
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作者 刘振龙 侯振宸 +5 位作者 胡晓青 任爽 郭秦炜 徐雁 龚熹 敖英芳 《北京大学学报(医学版)》 北大核心 2025年第2期384-387,共4页
目的:总结北京大学第三医院运动医学团队修复软骨损伤的手术技术经验,提出了一种关节镜下组织工程支架修复软骨损伤的手术技术,旨在规范化相关手术操作。方法:阐述关节镜下组织工程支架修复软骨损伤的手术操作技术及技巧,介绍关节镜下... 目的:总结北京大学第三医院运动医学团队修复软骨损伤的手术技术经验,提出了一种关节镜下组织工程支架修复软骨损伤的手术技术,旨在规范化相关手术操作。方法:阐述关节镜下组织工程支架修复软骨损伤的手术操作技术及技巧,介绍关节镜下脱钙皮质-松质骨支架完整的植入技术和手术流程,患者采取仰卧位,在麻醉完毕后建立关节镜手术入路,并在关节镜下对受损的部位进行探查;确认损伤部位的面积和部位后,对受损破碎的软骨进行清理,同时清理软骨边缘,确保切面平整、边缘稳定;在软骨损伤区域行微骨折术,之后再对损伤部位的大小进行测量;依据镜下测量结果对组织工程支架进行人工修剪,再通过套筒将支架直接植入;使用蜂窝状固定器植入可吸收钉固定支架;支架安装完毕后,反复屈伸膝关节10~20次,以确保稳定性和活动度;撤出关节镜并关闭创口。结果:从形态学和生物力学方面,脱钙皮质-松质骨支架都具有其他人工合成材料无法比拟的优势,支架的松质骨部分为细胞提供三维多孔生长空间,皮质骨部分则提供了必要的力学强度。手术采取全程关节镜下操作,把对患者的侵入性损伤最小化,同时使用可吸收钉进行固定,确保支架稳定,本技术可有效改善软骨损伤患者预后,对软骨损伤患者的关节镜下组织工程支架手术操作起到了规范作用。结论:通过关节镜下组织工程支架修复技术,可以成功对损伤的软骨进行修复,短期内改善症状,并提供较为理想的长期预后效果;对关节镜下组织工程支架的手术操作进行详解,以期对临床实践起到指导意义。 展开更多
关键词 关节镜 组织支架 软骨 运动医学 手术技术
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羽扇豆醇调节RhoA/ROCK信号通路对牙周炎大鼠牙周组织损伤的影响 被引量:1
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作者 王道荣 倪成励 丁鳌 《实用口腔医学杂志》 北大核心 2025年第3期321-327,共7页
目的:探讨羽扇豆醇(Lupeol)调节Ras同源基因家族成员A(RhoA)/Rho相关卷曲螺旋形成蛋白激酶(ROCK)信号通路对牙周炎大鼠牙周组织损伤的影响。方法:将SD大鼠随机分为对照组(NC组)、Model组、Lupeol低(Lupeol-L,16.67μg/kg)、中(Lupeol-M,... 目的:探讨羽扇豆醇(Lupeol)调节Ras同源基因家族成员A(RhoA)/Rho相关卷曲螺旋形成蛋白激酶(ROCK)信号通路对牙周炎大鼠牙周组织损伤的影响。方法:将SD大鼠随机分为对照组(NC组)、Model组、Lupeol低(Lupeol-L,16.67μg/kg)、中(Lupeol-M,33.34μg/kg)、高剂量组(Lupeol-H,66.68μg/kg)、维生素C(VC)组(100 mg/kg)、Rhosin(RhoA抑制剂)组(40 mg/kg)、Lupeol-H+Rhosin组(66.68μg/kg+40 mg/kg)(n=18)。除NC组外,其余各组大鼠均构建牙周炎模型。建模成功后给药处理,1次/d,持续21 d。ELISA检测血清IL-1β、TNF-α水平;亚甲蓝染色检测大鼠牙槽骨吸收;HE染色检测大鼠牙周组织病理变化;免疫组化检测大鼠牙周组织中OPG蛋白表达;TRAP染色检测大鼠牙周组织中破骨细胞数;Western blot检测大鼠牙周组织中OPG、RANKL、RhoA、ROCK1、ROCK2蛋白表达。结果:与NC组比较,Model组大鼠牙周组织病理损伤严重,TNF-α、IL-1β水平、牙槽嵴顶到釉牙骨质界(CEJ)距离、破骨细胞数、RANKL蛋白表达升高,成骨细胞数、OPG、RhoA、ROCK1、ROCK2蛋白表达降低(P<0.05);与Model组比较,Lupeol-L组、Lupeol-M组、Lupeol-H组、VC组大鼠牙周组织病理损伤减轻,TNF-α、IL-1β水平、牙槽嵴顶到CEJ距离、破骨细胞数、RANKL蛋白表达降低,成骨细胞数、OPG、RhoA、ROCK1、ROCK2蛋白表达升高,Rhosin组对应指标变化趋势与上述相反(P<0.05);Rhosin减弱了高剂量Lupeol对牙周炎大鼠牙周组织损伤的改善作用。结论:Lupeol改善牙周炎大鼠牙周组织损伤的机制可能与激活RhoA/ROCK通路有关。 展开更多
关键词 羽扇豆醇 牙周炎 破骨细胞 牙周组织
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1986—2021年江苏省沿海养殖池塘年际时空特征分析与优化管理
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作者 蔡丹丰 王慧南 +1 位作者 田鹏 胡求光 《农业机械学报》 北大核心 2025年第1期410-423,共14页
沿海养殖池塘对保障食物供给、提供优质蛋白和促进沿海社会经济发展具有重要作用,但养殖池塘快速扩张对区域生态系统稳定带来巨大挑战,急需加强沿海养殖池塘时空监测和可持续管理,而目前缺乏长时序养殖池塘年际空间分布数据集。本文基于... 沿海养殖池塘对保障食物供给、提供优质蛋白和促进沿海社会经济发展具有重要作用,但养殖池塘快速扩张对区域生态系统稳定带来巨大挑战,急需加强沿海养殖池塘时空监测和可持续管理,而目前缺乏长时序养殖池塘年际空间分布数据集。本文基于1986—2021年长时序Landsat遥感影像,借助Google Earth Engine平台与ArcGIS软件生成了江苏省沿海36年的养殖池溏空间分布数据,并探究其时空变化特征。结果表明:江苏省沿海养殖池塘识别总体精度和Kappa系数均大于91%和81%,分类结果准确。江苏省沿海养殖池塘快速增长,1986—2021年增长761.75 km2,且突出表现为缓慢增长阶段(1986—1996年)、快速增长阶段(1997—2001年)、波动增长阶段(2002—2005年)、快速增长阶段(2006—2013年)、波动下降阶段(2014—2021年)。空间分布集中于盐城市的大丰区、射阳县、响水县和东台市。江苏省沿海养殖池塘空间聚集于河口、港口和沿海平原,如临洪河河口、灌河河口、新淮河河口、新洋港、晚庄港和川东港,且空间聚集性加强。江苏省沿海养殖池塘扩张集中发生于1995—2015年,转入来源主要为其它建设用地、高覆被草地和滩涂。 展开更多
关键词 沿海养殖池塘 MNDWI指数 Google Earth Engine 空间格局 江苏省 时空特征
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基于Google Earth Engine平台的西南干热河谷植被时空演变特征及其驱动要素研究
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作者 张成 韦疏桐 +3 位作者 刘希宇 张尚弘 唐彩红 周扬 《生态学报》 北大核心 2025年第11期5398-5412,共15页
西南干热河谷地处横断山脉腹地,受到气候、地形及人类活动等要素的影响,垂向上植被分布格局迥异,低海拔区域为稀树灌草植被生态系统,高海拔区域为森林植被生态系统,是西南山区特殊的地理区系,也是我国典型的生态脆弱带之一。基于Landsa... 西南干热河谷地处横断山脉腹地,受到气候、地形及人类活动等要素的影响,垂向上植被分布格局迥异,低海拔区域为稀树灌草植被生态系统,高海拔区域为森林植被生态系统,是西南山区特殊的地理区系,也是我国典型的生态脆弱带之一。基于Landsat卫星遥感影像,通过Google earth engine (GEE)平台获取了1990—2020年四个季节归一化植被指数(NDVI)、地表温度(LST)和温度植被干旱指数(TVDI)数据,揭示了近30年西南干热河谷植被盖度的时空变化特征,并基于地形、气象、地表温度等要素分析了影响植被盖度变化的主要因素。结果发现干热河谷低海拔和高海拔区域的气温和地表温度均呈现显著增加,高海拔温度增加幅度大于低海拔地区。四个季节的NDVI在时间序列上亦呈现增加趋势,高山森林生态系统的植被增长速率(0.0077/a)显著高于稀树灌草生态系统(0.0027/a),且区域植被盖度均有向高植被盖度的趋势发展。在驱动要素方面,海拔、坡向、坡度等地形要素导致水热条件不同,从而使得高低海拔的植被类型存在明显差异,气温和地表温度的增加是导致植被盖度增加的主要诱因,在低海拔区域年均地表温度在20℃时植被盖度增加最快,而高海拔地区15℃时植被盖度增加最快,而超过该温度阈值后植被增加的速度有所下降。研究为指导西南干热河谷地区植被恢复提供了科学的管理建议及依据。 展开更多
关键词 气候变化 归一化植被指数(NDVI) 地表温度 温度植被干旱指数(TVDI) Google earth engine(GEE) 干热河谷
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应用型工科研究生“三位一体”实践培养体系研究——以林业工程学科家具设计与工程方向为例 被引量:1
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作者 陈星艳 陶涛 +9 位作者 吴义强 戴向东 李新功 欧阳周洲 朱耀军 曾冬 王丽平 胡孙跃 黄艳丽 邹伟华 《家具与室内装饰》 北大核心 2025年第4期139-144,共6页
以应用型工科研究生实践培养满足相关产业高层次人才需求这一重要课题为导向,结合研究生教育特点,提出了理论学习、在校实践和产业实习“三位一体”的实践培养体系构想,阐述了这一体系的三项基本要求,并以湖南省国内一流培育学科、国家... 以应用型工科研究生实践培养满足相关产业高层次人才需求这一重要课题为导向,结合研究生教育特点,提出了理论学习、在校实践和产业实习“三位一体”的实践培养体系构想,阐述了这一体系的三项基本要求,并以湖南省国内一流培育学科、国家林草局重点学科和湖南省重点学科——林业工程学科家具设计与工程方向为例探索了应用型工科研究生实践培养的具体方法。对于产教融合背景下校企协同创新,实现应用型工科类学科研究生教育供给侧与相关产业高端人才需求端的精准对接,促进相关产业实现高质量科学发展,具有较强的理论指导与借鉴意义。 展开更多
关键词 应用型工科 研究生教育 实践培养 林业工程学科 家具设计与工程 校内实践 产业实习 学科交叉
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面向新工科和工程教育专业认证的《机械设计》课程建设探索 被引量:1
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作者 刘世豪 马庆芬 +1 位作者 罗洪峰 林茂 《机械设计》 北大核心 2025年第9期196-202,共7页
为贯彻“新工科”和工程教育专业认证的核心理念,对海南大学机械设计制造及其自动化专业的机械设计课程教学与考核现状进行了深入分析。在此基础上总结了当前课程建设中存在的一系列问题,并提出了相应的课程建设方法,主要集中在以下几... 为贯彻“新工科”和工程教育专业认证的核心理念,对海南大学机械设计制造及其自动化专业的机械设计课程教学与考核现状进行了深入分析。在此基础上总结了当前课程建设中存在的一系列问题,并提出了相应的课程建设方法,主要集中在以下几个方面:课程教学内容、教学方式、实验教学和考核方式等。基于2019级机械设计制造及其自动化专业机械设计课程考核的实际案例,进行达成度分析,验证了课程建设所带来的积极影响,为学生的学习与工程创新能力的培养奠定了良好基础。 展开更多
关键词 新工科 工程教育专业认证 机械设计 课程建设 工程创新能力
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基础工程技术的发展与创新 被引量:8
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作者 王卫东 高文生 +3 位作者 龚维明 林毅峰 刘永超 吴江斌 《土木工程学报》 北大核心 2025年第2期97-117,共21页
随着经济和社会不断发展,我国工程建设领域出现了新的发展方向和机遇。基础工程面临复杂工程与水文地质条件、超高超深与大跨结构、环境低影响、绿色低碳与高效工业化等愈加复杂的需求和挑战,这也将持续推动基础工程技术的发展与创新。... 随着经济和社会不断发展,我国工程建设领域出现了新的发展方向和机遇。基础工程面临复杂工程与水文地质条件、超高超深与大跨结构、环境低影响、绿色低碳与高效工业化等愈加复杂的需求和挑战,这也将持续推动基础工程技术的发展与创新。文章结合近年来我国工程建设的成就与发展,从建筑市政、桥梁及海上风电基础工程面临的基本问题和特点出发,介绍各自领域的研究与技术进展。在建筑市政基础工程方面,重点介绍多塔楼高层建筑整体筏形基础、超高层建筑桩筏基础沉降分析与控制技术,以植入预制桩、高频免共振钢管桩、压入式沉井等为代表的绿色低碳、环境低影响技术,以及既有建筑基础加固与地下空间拓展等城市更新关键技术。在桥梁基础工程方面,重点介绍了冲刷和波浪等作用的相关理论研究,及桩基础、锚锭基础和沉井基础等基础形式的创新发展。在海上风电基础工程方面,重点介绍往复载荷作用下疲劳破坏,波浪辐射及绕射作用,动冰冲击和冰激振动等相关理论研究,及桩式、重力式、吸力筒式、漂浮式等基础形式的创新实践。另外,也简述基础工程在抗震与性能化设计、智能化和环境低影响的施工装备与技术、城市更新面临的既有基础检测、全寿命数字化监测等方面的研究与技术进展。 展开更多
关键词 基础工程 建筑市政 桥梁 海上风电 基础工程抗震 施工技术与装备 检测与监测
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和厚朴酚改善肺炎支原体肺炎大鼠炎症、氧化应激和肺组织损伤的作用机制 被引量:1
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作者 刘鑫 张宏蕊 +2 位作者 沈颖 刁玉巧 樊涛 《医学研究与战创伤救治》 北大核心 2025年第4期350-356,共7页
目的探究和厚朴酚(HNK)调节缺氧诱导因子-1α(HIF-1α)/Nod样受体蛋白3(NLRP3)信号通路对肺炎支原体(MP)肺炎大鼠炎症、氧化应激和肺组织损伤的影响。方法经鼻反复感染MP构建MP肺炎大鼠模型,60只MP肺炎模型大鼠随机分为:模型组、HNK低(1... 目的探究和厚朴酚(HNK)调节缺氧诱导因子-1α(HIF-1α)/Nod样受体蛋白3(NLRP3)信号通路对肺炎支原体(MP)肺炎大鼠炎症、氧化应激和肺组织损伤的影响。方法经鼻反复感染MP构建MP肺炎大鼠模型,60只MP肺炎模型大鼠随机分为:模型组、HNK低(12.5mg/kg)、中(25mg/kg)、高(50mg/kg)剂量组,HNK高剂量+HIF-1α过表达组(50mg/kg的HNK+10μg的pcDNA3.1-HIF-1α重组质粒),12只/组。另选择12只健康大鼠鼻滴150μL的培养基作为对照组。各组进行相应干预7d。酶联免疫吸附法检测血清免疫球蛋白M(IgM)、炎性因子肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)水平及氧化应激因子丙二醛、超氧化物歧化酶(SOD)水平;HE染色观察肺组织病理并进行肺组织损伤评分;脱氧核苷酸末端转移酶介导的dUTP缺口末端标记法染色检测肺组织细胞凋亡;荧光定量聚合酶链反应法和蛋白印迹法检测肺组织HIF-1α、NLRP3 mRNA和蛋白表达。结果与对照组比较,模型组肺泡松散,伴有充血出血、炎性细胞浸润、肺泡壁增厚,血清IgM、TNF-α、IL-6、丙二醛、肺组织损伤评分、肺组织细胞凋亡率、HIF-1α、NLRP3 mRNA和蛋白表达显著升高,SOD水平显著降低(P<0.01);与模型组比较,HNK低、中、高剂量组肺泡结构损伤、出血、充血、中性粒细胞浸润较少,血清IgM、TNF-α、IL-6、丙二醛、肺组织损伤评分、肺组织细胞凋亡率、HIF-1α、NLRP3 mRNA和蛋白表达呈剂量依赖性降低,SOD水平呈剂量依赖性降低升高(P<0.01);HIF-1α过表达可部分逆转高剂量HNK对MP肺炎大鼠肺组织病理损伤和上述指标的改善效果(P<0.01)。结论HNK可能通过抑制HIF-1α/NLRP3信号通路,改善MP肺炎大鼠炎症、氧化应激、肺组织损伤和细胞凋亡。 展开更多
关键词 和厚朴酚 缺氧诱导因子-1Α Nod样受体蛋白3 肺炎支原体肺炎 肺组织损伤 肺组织细胞凋亡
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