Journal of Zhejiang University-SCIENCE A最新文献

{"title":"Prediction of undeformed chip thickness distribution and surface roughness in ultrasonic vibration grinding of inner hole of bearings","authors":"Yanqin Li, Daohui Xiang, Guofu Gao, Feng Jiao, Bo Zhao","doi":"10.1631/jzus.a2200609","DOIUrl":"https://doi.org/10.1631/jzus.a2200609","url":null,"abstract":"","PeriodicalId":508023,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":" 16","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139790784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of ground effect on flow field structure and aerodynamic noise of high-speed trains","authors":"Xiaoming Tan, Linli Gong, Xiaohong Zhang, Zhigang Yang","doi":"10.1631/jzus.A2300034","DOIUrl":"https://doi.org/10.1631/jzus.A2300034","url":null,"abstract":"The simulation of the ground effect has always been a technical difficulty in wind tunnel tests of high-speed trains. In this paper, large eddy simulation and the curl acoustic integral equation were used to simulate the flow-acoustic field results of high-speed trains under four ground simulation systems (GSSs): “moving ground+rotating wheel”, “stationary ground+rotating wheel”, “moving ground+stationary wheel”, and “stationary ground+stationary wheel”. By comparing the fluid-acoustic field results of the four GSSs, the influence laws of different GSSs on the flow field structure, aero-acoustic source, and far-field radiation noise characteristics were investigated, providing guidance for the acoustic wind tunnel testing of high-speed trains. The calculation results of the aerodynamic noise of a 350 km/h high-speed train show that the moving ground and rotating wheel affect mainly the aero-acoustic performance under the train bottom. The influence of the rotating wheel on the equivalent sound source power of the whole vehicle was not more than 5%, but that of the moving ground slip was more than 15%. The average influence of the rotating wheel on the sound pressure level radiated by the whole vehicle was 0.3 dBA, while that of the moving ground was 1.8 dBA. 目 的 高速列车作为高速地面交通工具, 不可避免地会遇到地面效应问题. 地面效应模拟一直是高速列车风洞试验的技术难点. 地面效应现象的准确模拟对高速列车空气动力学和气动噪声的预测精度有很大的影响. 通过对比4种地面模拟系统(GSS)的流声场结果, 研究不同GSS对流场结构、 气动声源和远场辐射噪声特性的影响规律, 为高速列车声学风洞试验提供指导. 创新点 1. 搭建高速列车地面模拟系统, 模拟不同边界条件; 2. 明确轮对旋转与地面滑移对高速列车气动噪声幅值的相对增量及影响频率范围. 方 法 1. 在仿真系统中建立“移动地面+旋转轮对”、 “静止地面+旋转轮对”、 “移动地面+静止轮对”和“静止地面+静止轮对”四种地面模拟系统; 2. 采用大涡模拟和旋度声学积分方程, 对高速列车的流声场结果进行模拟; 3. 通过对比4种GSS的流声场结果, 研究不同GSS对流场结构、 气动声源和远场辐射噪声特性的影响规律. 结 论 1. 移动地面和旋转轮对是影响列车底部气动声学性能的主要因素; 2. 旋转轮对对整车等效声源功率的影响不大于5%, 且移动地面对整车等效声源功率的影响大于15%; 3. 旋转轮对对整车辐射声压级的平均影响为0.3 dBA, 且运动地面对整车辐射声压级的平均影响为1.8 dBA; 它们主要影响100 Hz以下的气动声学性能.","PeriodicalId":508023,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"15 3","pages":"147-160"},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140463566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transfer relation between subgrade frost heave and slab track deformation and vehicle dynamic response in seasonally frozen ground","authors":"Juanjuan Ren, Junhong Du, Kaiyao Zhang, Bin Yan, Jincheng Tian","doi":"10.1631/jzus.a2300303","DOIUrl":"https://doi.org/10.1631/jzus.a2300303","url":null,"abstract":"","PeriodicalId":508023,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"1 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140463992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Constitutive modelling of concrete material subjected to low-velocity projectile impact: insights into damage mechanism and target resistance","authors":"Shen Liu, Xieping Huang, X. Kong, Qin Fang","doi":"10.1631/jzus.A2300072","DOIUrl":"https://doi.org/10.1631/jzus.A2300072","url":null,"abstract":"This paper presents a numerical study to improve the understanding of the complex subject of penetration and perforation of concrete targets impacted by low-velocity projectiles. The main focus is on the damage mechanisms and the major factors that account for the target resistance of the concrete. An improved continuous surface cap model recently proposed was employed. The model was first equipped with element erosion criteria and was adequately validated by comparisons with ballistic experiments. Comprehensive numerical simulations were carried out where the individual influence of tensile, shear, and volumetric behaviors (pore collapse) of a concrete target on its ballistic performance was investigated. Results demonstrated that cratering on the front face and scabbing on the rear face of the concrete target were mainly dominated by its tensile behavior. The major target resistance came from the second tunneling stage which was primarily governed by the shear and volumetric behaviors of the concrete. Particularly, this study captured the pore collapse-induced damage phenomenon during the high-pressure tunneling stage, which has been extensively reported in experiments but has usually been neglected in previous numerical investigations. 目 的 弹体冲击作用下, 混凝土靶呈现三个阶段的典型破坏模式, 即正面成坑、 中间掘隧道及背面震塌, 但对三个阶段损伤破坏机理及混凝土靶抗侵彻阻力主要影响因素的认识一直存在很大争议. 拟标定近期提出的较为完善的混凝土帽盖弹塑性损伤本构, 全面探究弹体低速冲击下(弹体速度低于500 m/s)混凝土拉伸、 剪切及体积压缩行为对混凝土靶抗侵彻阻力及损伤破坏的影响机制. 创新点 1. 全面分析混凝土拉伸、 剪切及体积压缩行为对混凝土靶抗侵彻阻力及损伤破坏的影响机制; 2. 成功预测弹体在混凝土靶掘隧道高压力阶段孔隙坍缩引起的损伤行为. 方 法 1. 改进混凝土帽盖弹塑性本构, 引入单元删除准则(公式(19)), 标定模型参数(图2); 2. 与公开弹道试验定性定量结果对比, 验证材料本构、数值模型和参数的合理性(图6~8); 3. 数值模拟究混凝土拉伸、 剪切及体积压缩行为对混凝土靶体抗侵彻能力及损伤破坏模式的影响, 并与公开文献中主要发现进行讨论. 结 论 1. 混凝土正面成坑及背面震塌的形成主要由其拉伸力学行为决定, 而中间高压力掘隧道过程则由混凝土剪切及体积压缩行为决定. 2. 单轴压缩强度不是混凝土靶抗侵彻阻力主要影响因素, 其高压力下的剪切及体积压缩行为起决定作用, 且中间高压力掘隧道阶段是混凝土靶抗弹体侵彻的主要过程. 3. 拉伸力学行为在混凝土靶抗侵彻阻力计算模型中被普遍忽视, 但本文研究发现混凝土拉伸力学行为可显著影响弹体的残余速度, 因此其作用不容忽视.","PeriodicalId":508023,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"86 3","pages":"161-182"},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140462702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress relaxation properties of calcium silicate hydrate: a molecular dynamics study","authors":"Zhicheng Geng, Shengwen Tang, Yang Wang, H. A, Zhen He, Kai Wu, Lei Wang","doi":"10.1631/jzus.a2300476","DOIUrl":"https://doi.org/10.1631/jzus.a2300476","url":null,"abstract":"","PeriodicalId":508023,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"50 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140465957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution mechanism and quantitative characterization of initial micro-cracks in marble under triaxial compression","authors":"Zhiliang Wang, Songyu Li, Jianguo Wang, Ao Li, Weixiang Wang, Chenchen Feng, Jingjing Fu","doi":"10.1631/jzus.A2300159","DOIUrl":"https://doi.org/10.1631/jzus.A2300159","url":null,"abstract":"The initial micro-cracks affect the evolution characteristics of macroscopic deformation and failure of rock but are often ignored in theoretical calculation, numerical simulation, and mechanical experiments. In this study, we propose a quantitative analysis model to investigate the effects of initial micro-cracks on the evolution of marble deformation and failure. The relationship between the micro-crack propagation and the marble failure characteristics was comprehensively studied by combining theoretical analysis with a micro-computed tomography (micro-CT) scanning technique. We found that with the increase of confining pressure, the matrix elastic modulus of the marble first increased and then tended to be stable, while the micro-cracks increased exponentially. The sensitivity ranges of the marble sample matrix elastic modulus and micro-cracks to confining pressure were 0–30 MPa and 30–50 MPa, respectively. The porosity and Poisson’s ratio decreased exponentially. The increasing proportion of internal micro-cracks led to an increase in the sample non-uniformity. The samples presented mainly shear failure under triaxial compression, and the failure angle decreased linearly with the increase of confining pressure. The convergence direction of cracks decreased gradually. This quantitative analysis model could accurately portray the relationship between the overall macroscopic deformation and the deviatoric stress of the samples at the compaction and the linear elastic stages, thus deepening the understanding of the stress–strain behavior of rocks. 目的 岩石宏观变形破坏演化特征受其内部初始微裂纹的影响,但在理论计算、数值模拟和力学实验中,这部分影响往往被忽略。本文旨在提出一个定量分析模型来研究初始微裂纹对岩石变形破坏演化过程的影响。 创新点 1. 建立初始微裂纹占比定量分析的理论模型;2. 揭示围压对大理岩模型参数演化的影响。 方法 1. 通过理论推导,建立一种能进行岩石初始微裂纹占比定量分析的理论模型,并基于三轴压缩试样的应力分解改进该模型的表达式(公式(13)和(14));2. 通过三轴压缩试验,确定岩石初始裂隙精确分析的拟合区间,并分析围压对大理岩试样模型参数演化的影响(图5~7);3. 结合微CT扫描技术,对受载岩样的裂隙演化特征进行讨论与分析(图10和11)。 结论 1. 所建立的岩石初始微裂纹占比定量分析模型参数物理意义明确、确定方便;2. 随着围压的增加,试样孔隙度和泊松比均以指数函数的形式递减,基质部分弹性模量先增大后趋于稳定,而微裂纹弹性模量呈指数增长;3. 试样破坏是试样内部微裂纹扩展的结果,且宏观破坏角随着围压的增大而线性减小。","PeriodicalId":508023,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"28 3","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2024-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139437502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent progress in the development of dielectric elastomer materials and their multilayer actuators","authors":"Shengchao Jiang, Junbo Peng, Lvting Wang, Hanzhi Ma, Ye Shi","doi":"10.1631/jzus.A2300457","DOIUrl":"https://doi.org/10.1631/jzus.A2300457","url":null,"abstract":"Dielectric elastomers (DEs) have emerged as one of the most promising artificial muscle technologies, due to their exceptional properties such as large actuation strain, fast response, high energy density, and flexible processibility for various configurations. Over the past two decades, researchers have been working on developing DE materials with improved properties and exploring innovative applications of dielectric elastomer actuators (DEAs). This review article focuses on two main topics: recent material innovation of DEs and development of multilayer stacking processes for DEAs, which are important to promoting commercialization of DEs. It begins by explaining the working principle of a DEA. Then, recently developed strategies for preparing new DE materials are introduced, including reducing mechanical stiffness, increasing dielectric permittivity, suppressing viscoelasticity loss, and mitigating electromechanical instability without pre-stretching. In the next section, different multilayer stacking methods for fabricating multilayer DEAs are discussed, including conventional dry stacking, wet stacking, a novel dry stacking method, and micro-fabrication-enabled stacking techniques. This review provides a comprehensive and up-to-date overview of recent developments in high-performance DE materials and multilayer stacking methods. It highlights the progress made in the field and also discusses potential future directions for further advancements. 介电弹性体(DE)具有驱动应变大、 响应快、 能量密度高、 可灵活处理各种配置等特点, 已成为最具前景的人工肌肉技术之一. 在过去的二十年中, 研究人员一直致力于开发性能改善的DE材料, 并探索介电弹性体驱动器(DEA)的创新应用. 本文重点讨论了两大主题: 介电弹性体的材料创新和介电弹性体驱动器多层堆叠工艺的发展, 这对推动介电弹性体的商业化应用具有重要意义. 本文对高性能介电弹性体材料和多层堆叠方法的最新进展进行了综述, 强调了在该领域取得的进展, 并讨论了未来潜在的研究方向. 在广泛的商业应用之前, DE仍有几个问题需要解决. 第一, 设计能够在高驱动频率(100 Hz量级)下保持大而稳定驱动应变(超过100%)的DE材料. 第二, 解决DE和DEA长时间使用的稳定性. 为了提高寿命, 应仔细研究失效机理, 并根据机理适当调整DE材料的介电性能. 第三, 需要开发具有高环境耐受性的DE材料. 最后, 需要解决高电压驱动导致的安全问题. 叠层DE驱动器(MDEA)的开发与DE的材料创新同样重要, 但MDEA的制备仍存在许多挑战. 适用于超薄DE薄膜堆叠的叠层工艺需要被探索. 此外, 提高当前叠层方法的扩展性也很重要, 以兼容大规模制造工艺.","PeriodicalId":508023,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"6 2","pages":"1-23"},"PeriodicalIF":0.0,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139439368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biotreatment of incinerated bottom ash and biocementation of sand blocks using soybean urease","authors":"Xiaoniu Yu, Yidong Xu","doi":"10.1631/jzus.A2300006","DOIUrl":"https://doi.org/10.1631/jzus.A2300006","url":null,"abstract":"Because of the high cost of cultivating urease-producing bacteria (UPB), this paper proposes soybean-urease-induced carbonate precipitation (SUICP) as a novel biocement for treatment of nickel contaminants and cementation of sandy soil. We found the optimal soaking time and soybean-powder content to be 30 min and 130 g/L, respectively, based on a standard of 5 U of urease activity. The most efficient removal of nickel ions is obtained with an ideal mass ratio of urea to nickel ions to soybean-powder filtrate (SPF) of 1:2.4:20. The removal efficiency of nickel ions can reach 89.42% when treating 1 L of nickel-ion solution (1200 mg/L with the optimal mass ratio). In incinerated bottom ash (IBA), the removal efficiency of nickel ions is 99.33% with the optimal mass ratio. In biocemented sandy soil, the average unconfined compressive strength (UCS) of sand blocks cemented with soybean urease-based biocement can reach 118.89 kPa when the cementation level is 3. Currently, the average content of CaCO_3 in sand blocks is 2.52%. As a result, the SUICP process can be applied to remove heavy metal ions in wastewater or solid waste and improve the mechanical properties of soft soil foundations. 目 的 大豆脲酶基生物水泥与脲酶菌基生物水泥功能相同, 其同样可被应用于环境和土木工程中. 由于培养脲酶菌的过程复杂且成本较高, 本文提出使用简单且成本相对较低的大豆脲酶, 其可诱导碳酸盐沉淀, 是一类新型生物水泥. 它可被应用于污染物中重金属处理和软土地基加固. 在处理后的重金属污染物中, 可有效降低游离重金属的浓度至安全阀值以下; 在胶结后的砂土中, 可显著提高其力学性能. 创新点 1. 大豆脲酶可采用水浸泡法提取; 2. 根据最佳脲酶活性, 确定大豆粉末的最佳浸泡时间和用量; 3. 根据最佳去除率, 确定最佳去除镍离子的配方; 4. 根据脲酶水解机理和矿物形成的生物化学反应机制, 讨论大豆脲酶基生物水泥矿化固结镍离子和胶结砂土的机理和过程. 方 法 1. 通过浸泡大豆粉末, 根据最佳脲酶活性确定最佳浸泡时间和掺量(图S3和S4); 2. 通过调节尿素掺量、 大豆粉末滤液含量和矿化时间, 在溶液中镍离子最佳去除率下, 确定尿素、 镍离子与大豆粉末滤液的最佳质量比(图5a~5c); 3. 通过应用最佳质量比下的尿素和大豆粉末滤液, 可以有效去除垃圾焚烧底灰中镍离子和提升胶结砂土的力学性能(图6和7); 4. 通过大豆脲酶矿化固结镍和钙离子的示意图, 揭示大豆脲酶基生物水泥的形成机制和胶结机理(图8). 结 论 1. 大豆粉末与水混合可以释放大豆脲酶, 并溶于水中, 可催化分解尿素, 引起电导率变化, 从而确定脲酶活性; 2. 大豆粉末的最佳浸泡时间和掺量需要根据不同浸泡时间和掺量与脲酶活性的关系确定; 3. 尿素、 镍离子与大豆粉末滤液的最佳质量比需要根据不同尿素掺量、 大豆粉末滤液含量和矿化时间与镍离子去除率关系确定; 4. 通过应用最佳质量比下的尿素和大豆粉末滤液, 可以获得不同镍离子浓度下的去除率和不同胶结次数下的砂土的碳酸钙含量和无侧限抗压强度.","PeriodicalId":508023,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"31 11","pages":"36-46"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139539636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of the hygrothermal performance of two light-framed timber structure buildings under different operation modes","authors":"Wanqing Xu, Yucong Xue, Jiang Lu, Yifan Fan, Xiaoyu Luo","doi":"10.1631/jzus.A2200536","DOIUrl":"https://doi.org/10.1631/jzus.A2200536","url":null,"abstract":"目 的 夏热冬冷地区气候全年高湿且居民采用间歇用能辅以通风的方式调节环境, 由于建筑室内外环境条件复杂多变, 轻型木结构建筑在该区的适用性尚有待研究. 本文旨在研究用能季典型气象日及相应间歇用能工况下的室内环境及围护结构热湿传递特征, 并探究在不同条件下围护结构不同朝向及不同位置热湿传递的差异, 明确墙体冷凝霉变的关键位置, 为工程运用提供参考. 创新点 1. 建立轻型木结构建筑足尺模型, 并在墙体不同位置设置温湿度监测点进行实验与比较; 2. 以夏热冬冷地区间隙用能工况作为实验条件, 研究更加贴近真实情况. 方 法 1. 通过文献调研梳理夏热冬冷地区居民用能及通风习惯, 选择典型间歇工况作为实验条件. 2. 运用温湿度自记仪、 传感器对室内及墙体内部温湿度进行监测, 通过对比不同时刻、 位置的温湿度差异, 总结轻型木结构建筑室内环境及围护结构材料在典型工况下的热湿特征. 结 论 1. 一号建筑的总传热阻略高于二号建筑, 总传湿阻大大高于二号建筑, 其外墙对温湿度的变化具有更强的抵抗能力, 在室内外环境不理想时能较好地保持与调节室内环境; 而二号建筑在间歇用能和通风时相应较快. 2. 岩棉层两侧的材料容易出现相对湿度较高的状况, 夏季靠室内侧的石膏板具有高湿风险, 而冬季靠室外侧的定向刨花板(OSB(层具有高湿风险. Light-framed timber structure (LTS) buildings have been highly valued in recent years due to their low-carbon characteristics. However, the applicability of the building envelope is closely related to indoor and outdoor conditions. The hot summer and cold winter (HSCW) climate zone in China has high humidity and great temperature variation throughout the year, resulting in distinct outdoor environments in different seasons. The indoor environment is greatly affected by energy-consumption patterns and window-opening habits, which largely depend upon the regulation operations of occupants. All these interrelated factors lead to extremely complex boundary conditions on each side of the building envelope. Whether the structures of LTS buildings are applicable in this climate zone, therefore, needs to be carefully considered. In this study, two LTS buildings with different envelopes were established in Haining, China, situated in the HSCW climate zone, and selected as the study objects. Different operation modes were adopted to create a variety of indoor environments. Under each condition, the processes of heat and moisture transfer within the building envelopes and the indoor environment were monitored and compared. The comparison indicated that the building envelope with high moisture storage and insulation ability maintained a relatively stable indoor environment, especially when the environment changed abruptly. Conversely, if the outdoor environment was equable (e.g., relative humidity within the range of 30%–60%) or intermittent energy consumption modes were adopted, the building envelope with a low thermal inertia index and weak moisture-buffering ability performed better because it enabled a faster response of the indoor environment to air conditioning. Moreover, a high risk of moisture accumulation between the thermal insulation layer and other materials with a large water vapour transfer resistance factor was also identified, suggesting a higher requirement for the vapour insulation of the envelopes of LTS buildings.","PeriodicalId":508023,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"29 50","pages":"18-35"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139539932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biomimetic microchannel network with functional endothelium formed by sacrificial electrospun fibers inside 3D gelatin methacryloyl (GelMA) hydrogel models","authors":"Haoyu Sun, Haiyang Ma, Li Wang, Yang Liu, Tianyong Hou, Wen-jie Tang, Qing Yu, Meiwen An, Meiling Wen","doi":"10.1631/jzus.A23D0045","DOIUrl":"https://doi.org/10.1631/jzus.A23D0045","url":null,"abstract":"目 的 三维(3D)水凝胶模型在组织工程中起到了促进组织再生的关键作用. 三维水凝胶模型中的仿生微通道网络系统是实现最佳细胞功能的必要条件. 本文旨在研究利用电纺技术和牺牲模板法制备具有内部微通道网络的仿生水凝胶支架, 用于三维内皮细胞培养形成功能性人工微血管. 创新点 1. 首次利用静电纺丝技术成功制备直径>10 μm的纤维材料, 作为形成微通道网络的牺牲材料; 2. 通过反复挤压的方式, 在高浓度甲基丙烯酰化明胶(GelMA)水凝胶内成功创建了微通道和空腔, 从而创建了微血管样通道; 3. 成功在微通道腔内形成内皮细胞单层, 并研究了3D水凝胶支架表面和支架内对人脐静脉内皮细胞(HUVECs)的活性、 增殖、 形态发生和血管再生的影响. 方 法 1. 以难挥发的去离子水和易挥发的六氟异丙醇(HFIP)为溶剂, 通过优化配比及电纺条件, 使其静电纺直径更大的纤维, 用于形成微通道结构的牺牲材料(图1); 2. 合成并研究高浓度的纯GelMA水凝胶和支架的理化性能和生物相容性. 通过力学性能、溶胀性能和降解性能等表征和对比, 筛选出最优性能的支架(图2~5); 3. 通过对支架表面和支架内的内皮细胞培养, 量化对比内皮细胞的形态发生以及细胞核铺展, 研究支架对人工微血管形成的影响(图6~8). 结 论 1. 在室温条件下, 聚乙烯醇(PVA)纤维能够被聚丁二酸丁二醇酯(PBS)溶液快速溶解; 2. 通过力学性能、溶胀性能和降解性能等测试, 与纯GelMA水凝胶相比, 含微通道网络的仿生GelMA水凝胶力学性能有所下降. 虽然微通道网络的存在降低了其各种性能, 但仍有利于HUVECs的生长和增殖, 且满足组织再生的周期, 特别适用于三维细胞培养和组织工程应用; 3. CCK-8毒性测试和对细胞的活-死染色结果显示, 三种支架均具有良好的生物相容性. 在培养7 d后, 材料表面细胞相互连接形成管状结构, HUVECs在浓度为25%的支架比15%和20%的支架细胞数量显著增加, 且有更明显的铺展和管状结构. 这表明其状态良好, 支持了含内部结构的GelMA水凝胶支架的生物相容性, 且此支架可作为生物医学领域的3D细胞培养, 应证了上述所提到的内含微结构的水凝胶亦适用于细胞附着与增殖. 4. 经过对细胞的4′,6-二脒基-2-苯基吲哚(DAPI)和微丝染色, 结果显示培养3 d后, 在支架通道内形成了稳定的内皮单细胞层, 细胞核分布均匀且沿着孔道主轴方向排布, 微丝清晰可见, 大多倾向于轴向分布. 其次, 微孔道通过接触引导影响HUVECs的细胞行为与形态, 从而促进HUVECs形成微血管. 发现微通道管腔3D微环境通过接触引导促进融合的内皮细胞单层的形成, 进一步表明了此支架作为体外微血管的再生的适用性. 最后, 通过量化对比, 微通道加速了微血管的再生. Three-dimensional (3D) hydrogel models play a crucial role in tissue engineering for promoting tissue regeneration. A biomimetic microchannel network system in the 3D hydrogel model is necessary for optimal cellular function. This report describes the preparation of a biomimetic hydrogel scaffold with an internal microchannel network, using electrospinning techniques and the sacrificial template method for 3D cell culture. Microchannels and cavities were created within the gelatin methacryloyl (GelMA) hydrogel by sacrificing polyvinyl alcohol (PVA) electrospun fibers (>10 µm), resulting in the creation of microvessel-like channels. Mechanical characterizations, swelling properties, and biodegradation analysis were conducted to investigate the feasibility of a biomimetic microchannel network hydrogel scaffold for 3D cell culture applications. Compared to pure GelMA hydrogel, the hydrogel with microchannels promoted cell proliferation, adhesion, and endothelial tube formation. Moreover, the results confirmed that the biomimetic microchannel network scaffold had a major impact on the distribution and arrangement of human umbilical vein endothelial cells (HUVECs) and can enable the formation of artificial microvasculature by the culture of HUVECs and cell media perfusion.","PeriodicalId":508023,"journal":{"name":"Journal of Zhejiang University-SCIENCE A","volume":"42 21","pages":"79-96"},"PeriodicalIF":0.0,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139540167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}