The range of coal-mine underground goaf has continuously expanded over time.Caving,fracture,and deformation zones have also changed,thereby inducing coal-mine water inrush and other environmental disasters.In this stu...The range of coal-mine underground goaf has continuously expanded over time.Caving,fracture,and deformation zones have also changed,thereby inducing coal-mine water inrush and other environmental disasters.In this study,4 D seismic monitoring technology that is effective in reservoir development was used to monitor abnormal changes in coal-mine underground goaf to explore the feasibility of the method.Taking a coal mine in Hancheng,Shaanxi as an example,we used the aforementioned technology to dynamically monitor the abnormal changes in the goaf.Based on the 4 D seismic data obtained in the experiment and the abnormal change characteristics of the coal-mine goaf,the method of 4 D seismic data processing in reservoir was improved.A set of 4 D data processing flow for the goaf was established,and the anomalies in the surface elevation and overlying strata velocity caused by collapse were corrected.We have made the following improvements to the method of 4 D seismic data processing in the reservoir:(1)the static correction problem caused by the changes of surface elevation and destruction of the low-velocity layer has been solved through fusion static correction to comb the low-frequency components of elevation statics with the high-frequency components of refraction statics;(2)the problem of overlying strata velocity changes in the goaf caused by collapse has been solved through the velocity consistency method;(3)the problem of reflection event pull-down in the disturbance area has been solved through space-varying moveout correction based on cross-correlation;and(4)amplitude anomalies in the coal seam caused by the goaf have been addressed using the correction method of space-varying amplitude.Results show that the 4 D seismic data processing and interpretation method established in this study is reasonable and effective.展开更多
随着建筑工程项目的日益复杂性,导致项目管理的难度增加,传统进度管理作为施工管理的主要内容,模式变的难以适用,本文将引入在以建筑信息化模型(Build Information Model)为基础上发展起来的BIM-4D技术的进度管理模式,通过对比分析,来...随着建筑工程项目的日益复杂性,导致项目管理的难度增加,传统进度管理作为施工管理的主要内容,模式变的难以适用,本文将引入在以建筑信息化模型(Build Information Model)为基础上发展起来的BIM-4D技术的进度管理模式,通过对比分析,来论证在BIM-4D技术下的进度管理模式的适用性和优越性。展开更多
Setting time as the fourth dimension,4D printing allows us to construct dynamic structures that can change their shape,property,or functionality over time under stimuli,leading to a wave of innovations in various fiel...Setting time as the fourth dimension,4D printing allows us to construct dynamic structures that can change their shape,property,or functionality over time under stimuli,leading to a wave of innovations in various fields.Recently,4D printing of smart biomaterials,biological components,and living cells into dynamic living 3D constructs with 4D effects has led to an exciting field of 4D bioprinting.4D bioprinting has gained increasing attention and is being applied to create programmed and dynamic cell-laden constructs such as bone,cartilage,and vasculature.This review presents an overview on 4D bioprinting for engineering dynamic tissues and organs,followed by a discussion on the approaches,bioprinting technologies,smart biomaterials and smart design,bioink requirements,and applications.While much progress has been achieved,4D bioprinting as a complex process is facing challenges that need to be addressed by transdisciplinary strategies to unleash the full potential of this advanced biofabrication technology.Finally,we present future perspectives on the rapidly evolving field of 4D bioprinting,in view of its potential,increasingly important roles in the development of advanced dynamic tissues for basic research,pharmaceutics,and regenerative medicine.展开更多
Time-dependent structure analysis theory has been proved to be more accurate and reliable compared to commonly used methods during construction. However, so far applications are limited to partial period and part of t...Time-dependent structure analysis theory has been proved to be more accurate and reliable compared to commonly used methods during construction. However, so far applications are limited to partial period and part of the structure because of immeasurable artificial intervention. Based on the building informa-tion model (BIM) and four-dimensional (4D) technology, this paper proposes an improves structure analysis method, which can generate structural geometry, resistance model, and loading conditions automatically by a close interlink of the schedule information, architectural model, and material properties. The method was applied to a safety analysis during a continuous and dynamic simulation of the entire construction process. The results show that the organic combination of the BIM, 4D technology, construction simulation, and safety analysis of time-dependent structures is feasible and practical. This research also lays a foundation for further researches on building lifecycle management by combining architectural design, structure analysis, and construction management.展开更多
基金funded by the National Key Research and Development Program Subject(No.2018YFC0807804)。
文摘The range of coal-mine underground goaf has continuously expanded over time.Caving,fracture,and deformation zones have also changed,thereby inducing coal-mine water inrush and other environmental disasters.In this study,4 D seismic monitoring technology that is effective in reservoir development was used to monitor abnormal changes in coal-mine underground goaf to explore the feasibility of the method.Taking a coal mine in Hancheng,Shaanxi as an example,we used the aforementioned technology to dynamically monitor the abnormal changes in the goaf.Based on the 4 D seismic data obtained in the experiment and the abnormal change characteristics of the coal-mine goaf,the method of 4 D seismic data processing in reservoir was improved.A set of 4 D data processing flow for the goaf was established,and the anomalies in the surface elevation and overlying strata velocity caused by collapse were corrected.We have made the following improvements to the method of 4 D seismic data processing in the reservoir:(1)the static correction problem caused by the changes of surface elevation and destruction of the low-velocity layer has been solved through fusion static correction to comb the low-frequency components of elevation statics with the high-frequency components of refraction statics;(2)the problem of overlying strata velocity changes in the goaf caused by collapse has been solved through the velocity consistency method;(3)the problem of reflection event pull-down in the disturbance area has been solved through space-varying moveout correction based on cross-correlation;and(4)amplitude anomalies in the coal seam caused by the goaf have been addressed using the correction method of space-varying amplitude.Results show that the 4 D seismic data processing and interpretation method established in this study is reasonable and effective.
文摘随着建筑工程项目的日益复杂性,导致项目管理的难度增加,传统进度管理作为施工管理的主要内容,模式变的难以适用,本文将引入在以建筑信息化模型(Build Information Model)为基础上发展起来的BIM-4D技术的进度管理模式,通过对比分析,来论证在BIM-4D技术下的进度管理模式的适用性和优越性。
基金support from CUHK’s Vice-Chancellor Early Career Professorship Scheme and CUHK Research Committee (via Direct Grant for Research 2022/2023,4055182)supported by the Lee Quo Wei and Lee Yik Hoi Lun Professorship in Tissue Engineering and Regenerative Medicine of CUHK+2 种基金supported by the Center for Neuromusculoskeletal Restorative Medicine (to RST,ZAL,GL,and PSY),under the Health@InnoHK program launched by the Innovation and Technology Commission,the Government of the Hong Kong SAR of the People’s Republic of China,the National Natural Science Foundation of China (to ZAL,82302753)the Research Grants Council of Hong Kong SAR of the People’s Republic of China (to ZAL,24203523)support from the Shenzhen Science and Technology Project (JCYJ20210324102815040).
文摘Setting time as the fourth dimension,4D printing allows us to construct dynamic structures that can change their shape,property,or functionality over time under stimuli,leading to a wave of innovations in various fields.Recently,4D printing of smart biomaterials,biological components,and living cells into dynamic living 3D constructs with 4D effects has led to an exciting field of 4D bioprinting.4D bioprinting has gained increasing attention and is being applied to create programmed and dynamic cell-laden constructs such as bone,cartilage,and vasculature.This review presents an overview on 4D bioprinting for engineering dynamic tissues and organs,followed by a discussion on the approaches,bioprinting technologies,smart biomaterials and smart design,bioink requirements,and applications.While much progress has been achieved,4D bioprinting as a complex process is facing challenges that need to be addressed by transdisciplinary strategies to unleash the full potential of this advanced biofabrication technology.Finally,we present future perspectives on the rapidly evolving field of 4D bioprinting,in view of its potential,increasingly important roles in the development of advanced dynamic tissues for basic research,pharmaceutics,and regenerative medicine.
基金the National Natural Science Foundation of China (No. 50478015) the National Technological Support Program for the 11th Five-Year Plan of China (No. 2006BAJ10B07)
文摘Time-dependent structure analysis theory has been proved to be more accurate and reliable compared to commonly used methods during construction. However, so far applications are limited to partial period and part of the structure because of immeasurable artificial intervention. Based on the building informa-tion model (BIM) and four-dimensional (4D) technology, this paper proposes an improves structure analysis method, which can generate structural geometry, resistance model, and loading conditions automatically by a close interlink of the schedule information, architectural model, and material properties. The method was applied to a safety analysis during a continuous and dynamic simulation of the entire construction process. The results show that the organic combination of the BIM, 4D technology, construction simulation, and safety analysis of time-dependent structures is feasible and practical. This research also lays a foundation for further researches on building lifecycle management by combining architectural design, structure analysis, and construction management.
文摘采用单因素法和响应面法相结合,对合成标题化合物的工艺条件进行优化。在单因素的实验基础上,再采用响应面法对原料配比、反应时间和反应后处理p H这3个关键因素进行优化分析,得到了标题化合物收率的计算模型,并得到优化条件:原料物质的量配比为n(2-氨基间苯二酚盐酸盐)∶n(乙基黄原酸钾)=1∶1.42,反应时间为4 h,反应后处理调节至p H 5,此条件下合成产率为65.28%。该合成工艺条件产率较高且稳定,可作为合成标题化合物的实验依据。
