Spectrum characteristics of different types of seismic waves and dynamic response characteristics of super high-rise building structures under long-period ground motions were comparatively analyzed. First, the ground ...Spectrum characteristics of different types of seismic waves and dynamic response characteristics of super high-rise building structures under long-period ground motions were comparatively analyzed. First, the ground response wave (named LS-R wave) of a soft soil site with deep deposit, taking long-period bedrock seismic record as input, was calculated by wave propagation method. After that, a TOMAKOMAI station long-period seismic record from the Tokachi-Oki earthquake and conventional E1-Centro wave were also chosen. Spectrum characteristics of these waves were analyzed and compared. Then, a series of shaking table tests were performed on a 1:50 scale super high-rise structural model under these seismic waves. Furthermore, numerical simulation of the prototype structure under these excitations was conducted, and structure damages under different intensive ground motions were discussed. The results show that: 1) Spectrum characteristics of ground response wave are significantly influenced by soft soil site with deep deposit, and the predominant period has an increasing trend. 2) The maximum acceleration amplification factor of the structure under the TOM wave is two times that under the E1-Centro wave; while the maximum displacement response of the structure under the TOM wave is 4.4 times that under the E1-Centro wave. Long-period ground motions show greater influences on displacement responses than acceleration responses for super high-rise building structures. 3) Most inelastic damage occurs at the upper 1/3 part of the super high-rise building when subjected to long-period ground motions.展开更多
For super high-rise buildings, the vibration period of the basic mode is several seconds, and it is very close to the period of the fluctuating wind. The damping of super high-rise buildings is low, so super high-rise...For super high-rise buildings, the vibration period of the basic mode is several seconds, and it is very close to the period of the fluctuating wind. The damping of super high-rise buildings is low, so super high-rise buildings are very sensitive to fluctuating wind. The wind load is one of the key loads in the design of super high-rise buildings. It is known that only the basic mode is needed in the wind-response analysis of tall buildings. However, for super high-rise buildings, especially for the acceleration response, because of the frequency amplification of the high modes, the high modes and the mode coupling may need to be considered. Three typical super high-rise projects with the SMPSS in wind tunnel tests and the random vibration theory method were used to analyze the effect of high modes on the wind-induced response. The conclusions can be drawn as follows. First, for the displacement response, the basic mode is dominant, and the high modes can be neglected. Second, for the acceleration response, the high modes and the mode coupling should be considered. Lastly, the strain energy of modes can only give the vibration energy distribution of the high-rise building, and it cannot describe the local wind-induced vibration of high-rise buildings, especially for the top acceleration response.展开更多
In recent years with the increasing number of super high-rise buildings and the ever-expanding scale the anti-smoke construction technology has attracted more and more attention.Based on this situation,this paper anal...In recent years with the increasing number of super high-rise buildings and the ever-expanding scale the anti-smoke construction technology has attracted more and more attention.Based on this situation,this paper analyzes the smoke control technology of super high-rise buildings.The paper analyzes the importance of the application of anti-smoke construction technology in super high-rise buildings,analyzes the problems in the construction of smoke control and super high-rise buildings.The anti-smoke construction technology was studied and I hope that it can benefit the application of anti-smoke construction technology in high-rise buildings.展开更多
With the development of economy and society and the growth of population,the high-rise and multi-function of commercial buildings have become an international trend.But it also poses huge fire hazards.Most of the exis...With the development of economy and society and the growth of population,the high-rise and multi-function of commercial buildings have become an international trend.But it also poses huge fire hazards.Most of the existing studies’research objects are predominantly high-rise residential buildings,without considering the impact of different functional zones(Standard floor,entertainment zone,office zone,equipment room and so on)and personnel distribution of commercial buildings evacuation.And the influence of using elevators to carry evacuees on the refuge floor on personnel evacuation is rarely studied.In this work,the fire scenario of the Yangtze River InternationalConferenceCenter,a high-rise commercial building,is simulated with the Pyrosim programto get the necessary parameters under various fire scenarios and to calculate the available evacuation time TASET.At the same time,according to the complex functional zone of the commercial high-rise building and the distribution of people in different time periods,a reasonable evacuation strategy is developed and simulated by Pathfinder software.The results indicate that unorganized evacuation will lead individuals to take the erroneous evacuation route,resulting in a vast region of congestion;comprehensive consideration of the time staggering and the reasonable distribution of evacuation routes can significantly improve evacuation efficiency,and the TRSET of night and working hours is 36.6%–55.3%and 49.9%–79.6%of unorganized evacuation,respectively.For the night fire,60%of the people use elevator-refuge floor to evacuate is the optimal strategy;for the fire during working hours,half of the people on standard floors use the elevator to evacuate and people on multifunctional floors evacuate in four batches is the best plan.The results of this study can provide viable solutions and a foundation for analyzing the fire evacuation and safety of big commercial high-rise buildings.展开更多
Collisions between a moving mass and an anti-collision device increase structural responses and threaten structural safety.An active mass damper(AMD)with stroke limitations is often used to avoid collisions.However,a ...Collisions between a moving mass and an anti-collision device increase structural responses and threaten structural safety.An active mass damper(AMD)with stroke limitations is often used to avoid collisions.However,a strokelimited AMD control system with a fixed limited area shortens the available AMD stroke and leads to significant control power.To solve this problem,the design approach with variable gain and limited area(VGLA)is proposed in this study.First,the boundary of variable-limited areas is calculated based on the real-time status of the moving mass.The variable gain(VG)expression at the variable limited area is deduced by considering the saturation of AMD stroke.Then,numerical simulations of a stroke-limited AMD control system with VGLA are conducted on a high-rise building structure.These numerical simulations show that the proposed approach has superior strokelimitation performance compared with a stroke-limited AMD control system with a fixed limited area.Finally,the proposed approach is validated through experiments on a four-story steel frame.展开更多
To enable the experimental assessment of the seismic performance of full-scale nonstructural elements with multiple engineering parameters(EDPs),a three-layer testbed named Nonstructural Element Simulator on Shake Tab...To enable the experimental assessment of the seismic performance of full-scale nonstructural elements with multiple engineering parameters(EDPs),a three-layer testbed named Nonstructural Element Simulator on Shake Table(NEST)has been developed.The testbed consists of three consecutive floors of steel structure.The bottom two floors provide a space to accommodate a full-scale room.To fully explore the flexibility of NEST,we propose a novel control strategy to generate the required shake table input time histories for the testbed to track the target floor motions of the buildings of interest with high accuracy.The control strategy contains two parts:an inverse dynamic compensation via simulation of feedback control systems(IDCS)algorithm and an offline iteration procedure based on a refined nonlinear numerical model of the testbed.The key aspects of the control strategy were introduced in this paper.Experimental tests were conducted to simulate the seismic responses of a full-scale office room on the 21^(st)floor of a 42-story high-rise building.The test results show that the proposed control strategy can reproduce the target floor motions of the building of interest with less than 20%errors within the specified frequency range.展开更多
In recent years, super high-rise buildings (>500 m) are developing very quickly and become an important frontier of civil engineering. The collapse resistance of super high-rise buildings subjected to extremely str...In recent years, super high-rise buildings (>500 m) are developing very quickly and become an important frontier of civil engineering. The collapse resistance of super high-rise buildings subjected to extremely strong earthquake is a critical problem that must be intensively studied. This paper builds up a nonlinear finite element model of the tallest building in China, Shang- hai Tower (632 m), and proposes the modeling method and failure criteria for different structural elements. The dynamic char- acters of this building are then analyzed, and the possible failure modes and collapse processes due to earthquakes are pre- dicted, as well as the corresponding collapse mechanism. This work will be helpful in collapse prevention and the seismic design of super high-rise buildings.展开更多
Ground motion intensity measure (IM) is an important part in performance-based seismic design. A reasonable and efficient IM can make the prediction of the structural seismic responses more accurate. Therefore, a more...Ground motion intensity measure (IM) is an important part in performance-based seismic design. A reasonable and efficient IM can make the prediction of the structural seismic responses more accurate. Therefore, a more reasonable IM for super high-rise buildings is proposed in this paper. This IM takes into account the significant characteristic that higher-order vibration modes play important roles in the seismic response of super high-rise buildings, as well as the advantages of some existing IMs. The key parameter of the proposed IM is calibrated using a series of time-history analyses. The collapse simulations of two super high-rise buildings are used to discuss the suitability of the proposed IM and some other existing IMs. The results indicate that the proposed IM yields a smaller coefficient of variation for the critical collapse status than other existing IMs and performs well in reflecting the contribution of higher-order vibration modes to the structural response. Hence, the proposed IM is more applicable to seismic design for super high-rise buildings than other IMs.展开更多
旨在分析子午岭黑山羊的群体遗传多样性和亲缘关系以及家系结构,为子午岭黑山羊的保护和利用提供依据。本研究通过简化基因组测序(super-genotyping by sequencing,Super-GBS)技术对99只(10公/89母)成年子午岭黑山羊进行全基因组SNP检...旨在分析子午岭黑山羊的群体遗传多样性和亲缘关系以及家系结构,为子午岭黑山羊的保护和利用提供依据。本研究通过简化基因组测序(super-genotyping by sequencing,Super-GBS)技术对99只(10公/89母)成年子午岭黑山羊进行全基因组SNP检测。利用Plink软件计算观测杂合度(Ho)、期望杂合度(He)、多态信息含量(PIC)、核苷酸多样性(Pi)、有效等位基因数(Ne)及次要等位基因频率(MAF)等6项遗传多样性指标;GCTA软件进行主成分分析及基因组亲缘关系G矩阵构建;Plink软件构建IBS遗传距离矩阵,R语言绘制热图;PHYLP构建系统发育树;detect RUNS工具检测ROH。结果表明,99只子午岭黑山羊个体共检测到996042个SNPs。子午岭黑山羊群体的PIC、Pi、Ne及MAF值分别是0.161、0.193、1.295、0.130,且Ho(0.167)低于He(0.192),说明子午岭黑山羊群体遗传多样性较低。G矩阵和IBS遗传距离结果均表明子午岭黑山羊群体间大部分个体间亲缘关系较远。主成分分析结果揭示子午岭黑山羊群体内部不存在明显分化,系统发育树结果说明子午岭黑山羊群体公羊可大致分为6个家系,所有家系公羊数量较少。子午岭黑山羊群体的近交系数FROH为0.0496,说明子午岭黑山羊群体内部近交程度相对较低。综上所述,子午岭黑山羊群体遗传多样性较低,大部分个体间亲缘关系较远,群体内近交程度较低,后期应注意后代的选育,避免血统流失。展开更多
Cost overrun is a common problem in construction projects worldwide.Most Indian construction projects,particularly those involving high-rise buildings,have had severe cost overruns.For managers,architects,engineers,an...Cost overrun is a common problem in construction projects worldwide.Most Indian construction projects,particularly those involving high-rise buildings,have had severe cost overruns.For managers,architects,engineers,and contractors,completing building projects within the specified cost budget has become the most important and hard assignment.Since it is common for high-rise building projects to go over budget,the aim of this study is to find out the causes of cost overruns and provide effective measures.The study found 70 cost overrun factors based on a comprehensive literature review and expert opinions.A Google form questionnaire was distributed to 150 construction professionals across India.After following up,101 of the 150 responses were received.A five-point Likert scale was used and the acquired data was analyzed and ranked using the Relative Importance Index(RII)technique.According to the findings of RII,the top ten critical factors influencing cost overruns were frequent change orders during construction by the owner,delay in construction,escalation of material prices,market inflation or deflation,rework,frequent changes in design,inaccurate evaluation of the project timeline,unforeseen ground condition,inaccurate quantity take-off,and delay in progressive payment by the owner.Spearman’s rank correlation test revealed that there is a very significant relationship between the rankings of factors provided by the owner,the consultant,and the contractor.In addition,a factor analysis tool in the SPSS software was also used to categorize the seventy factors into sixteen core components.The top ten critical factors were presented to subject matter experts,and their suggestions were being compiled.These results are expected to help construction professionals minimize cost overruns,improve cost control measures,and initiate future research.展开更多
Convolutional neural networks depend on deep network architectures to extract accurate information for image super‐resolution.However,obtained information of these con-volutional neural networks cannot completely exp...Convolutional neural networks depend on deep network architectures to extract accurate information for image super‐resolution.However,obtained information of these con-volutional neural networks cannot completely express predicted high‐quality images for complex scenes.A dynamic network for image super‐resolution(DSRNet)is presented,which contains a residual enhancement block,wide enhancement block,feature refine-ment block and construction block.The residual enhancement block is composed of a residual enhanced architecture to facilitate hierarchical features for image super‐resolution.To enhance robustness of obtained super‐resolution model for complex scenes,a wide enhancement block achieves a dynamic architecture to learn more robust information to enhance applicability of an obtained super‐resolution model for varying scenes.To prevent interference of components in a wide enhancement block,a refine-ment block utilises a stacked architecture to accurately learn obtained features.Also,a residual learning operation is embedded in the refinement block to prevent long‐term dependency problem.Finally,a construction block is responsible for reconstructing high‐quality images.Designed heterogeneous architecture can not only facilitate richer structural information,but also be lightweight,which is suitable for mobile digital devices.Experimental results show that our method is more competitive in terms of performance,recovering time of image super‐resolution and complexity.The code of DSRNet can be obtained at https://github.com/hellloxiaotian/DSRNet.展开更多
The sol-gel method is used to prepare a new nano-alumina aerogel structure and the thermal properties of this nanomaterial are investigated comprehensively using electron microscope scanning,thermal analysis,X-ray and...The sol-gel method is used to prepare a new nano-alumina aerogel structure and the thermal properties of this nanomaterial are investigated comprehensively using electron microscope scanning,thermal analysis,X-ray and infrared spectrometer analysis methods.It is found that the composite aerogel alumina material has a multi-level porous nano-network structure.When employed for the thermal insulation of high-rise buildings,the alumina nanocomposite aerogel material can lead to effective energy savings in winter.However,it has almost no energy-saving effect on buildings where energy is consumed for cooling in summer.展开更多
The top goal of modern medicine is treating disease without destroying organ structures and making patients as healthy as they were before their sickness.Minimally invasive surgery(MIS)has dominated the surgical realm...The top goal of modern medicine is treating disease without destroying organ structures and making patients as healthy as they were before their sickness.Minimally invasive surgery(MIS)has dominated the surgical realm because of its lesser invasiveness.However,changes in anatomical structures of the body and reconstruction of internal organs or different organs are common after traditional surgery or MIS,decreasing the quality of life of patients post-operation.Thus,I propose a new treatment mode,super MIS(SMIS),which is defined as“curing a disease or lesion which used to be treated by MIS while preserving the integrity of the organs”.In this study,I describe the origin,definition,operative channels,advantages,and future perspectives of SMIS.展开更多
基金Project(50978198) supported by the National Natural Science Foundation of ChinaProject(SLDRCE08-B-03) supported by the Ministry of Science and Technology of China
文摘Spectrum characteristics of different types of seismic waves and dynamic response characteristics of super high-rise building structures under long-period ground motions were comparatively analyzed. First, the ground response wave (named LS-R wave) of a soft soil site with deep deposit, taking long-period bedrock seismic record as input, was calculated by wave propagation method. After that, a TOMAKOMAI station long-period seismic record from the Tokachi-Oki earthquake and conventional E1-Centro wave were also chosen. Spectrum characteristics of these waves were analyzed and compared. Then, a series of shaking table tests were performed on a 1:50 scale super high-rise structural model under these seismic waves. Furthermore, numerical simulation of the prototype structure under these excitations was conducted, and structure damages under different intensive ground motions were discussed. The results show that: 1) Spectrum characteristics of ground response wave are significantly influenced by soft soil site with deep deposit, and the predominant period has an increasing trend. 2) The maximum acceleration amplification factor of the structure under the TOM wave is two times that under the E1-Centro wave; while the maximum displacement response of the structure under the TOM wave is 4.4 times that under the E1-Centro wave. Long-period ground motions show greater influences on displacement responses than acceleration responses for super high-rise building structures. 3) Most inelastic damage occurs at the upper 1/3 part of the super high-rise building when subjected to long-period ground motions.
基金National Natural Science Foundation of China Under Grant No.50908044 Jiangsu Provincial Natural Science Foundation of China Under Grant No.SBK201123270 a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions and StateKey Lab of Subtropical Building Science,South China University of Technology Under Grant No.2011KA05
文摘For super high-rise buildings, the vibration period of the basic mode is several seconds, and it is very close to the period of the fluctuating wind. The damping of super high-rise buildings is low, so super high-rise buildings are very sensitive to fluctuating wind. The wind load is one of the key loads in the design of super high-rise buildings. It is known that only the basic mode is needed in the wind-response analysis of tall buildings. However, for super high-rise buildings, especially for the acceleration response, because of the frequency amplification of the high modes, the high modes and the mode coupling may need to be considered. Three typical super high-rise projects with the SMPSS in wind tunnel tests and the random vibration theory method were used to analyze the effect of high modes on the wind-induced response. The conclusions can be drawn as follows. First, for the displacement response, the basic mode is dominant, and the high modes can be neglected. Second, for the acceleration response, the high modes and the mode coupling should be considered. Lastly, the strain energy of modes can only give the vibration energy distribution of the high-rise building, and it cannot describe the local wind-induced vibration of high-rise buildings, especially for the top acceleration response.
文摘In recent years with the increasing number of super high-rise buildings and the ever-expanding scale the anti-smoke construction technology has attracted more and more attention.Based on this situation,this paper analyzes the smoke control technology of super high-rise buildings.The paper analyzes the importance of the application of anti-smoke construction technology in super high-rise buildings,analyzes the problems in the construction of smoke control and super high-rise buildings.The anti-smoke construction technology was studied and I hope that it can benefit the application of anti-smoke construction technology in high-rise buildings.
基金the grant fromthe Key Technologies Research and Development Program(Grant No.2021YFF0602005)the National Natural Science Foundation of China(No.51678135)the Fundamental Research Funds for the Central Universities(Nos.2242022k30031,2242022k30033).
文摘With the development of economy and society and the growth of population,the high-rise and multi-function of commercial buildings have become an international trend.But it also poses huge fire hazards.Most of the existing studies’research objects are predominantly high-rise residential buildings,without considering the impact of different functional zones(Standard floor,entertainment zone,office zone,equipment room and so on)and personnel distribution of commercial buildings evacuation.And the influence of using elevators to carry evacuees on the refuge floor on personnel evacuation is rarely studied.In this work,the fire scenario of the Yangtze River InternationalConferenceCenter,a high-rise commercial building,is simulated with the Pyrosim programto get the necessary parameters under various fire scenarios and to calculate the available evacuation time TASET.At the same time,according to the complex functional zone of the commercial high-rise building and the distribution of people in different time periods,a reasonable evacuation strategy is developed and simulated by Pathfinder software.The results indicate that unorganized evacuation will lead individuals to take the erroneous evacuation route,resulting in a vast region of congestion;comprehensive consideration of the time staggering and the reasonable distribution of evacuation routes can significantly improve evacuation efficiency,and the TRSET of night and working hours is 36.6%–55.3%and 49.9%–79.6%of unorganized evacuation,respectively.For the night fire,60%of the people use elevator-refuge floor to evacuate is the optimal strategy;for the fire during working hours,half of the people on standard floors use the elevator to evacuate and people on multifunctional floors evacuate in four batches is the best plan.The results of this study can provide viable solutions and a foundation for analyzing the fire evacuation and safety of big commercial high-rise buildings.
基金This research was founded by the Funds for Creative Research Groups of National Natural Science Foundation of China(Grant No.51921006)the National Natural Science Foundations of China(Grant No.51978224)+2 种基金the National Major Scientific Research Instrument Development Program of China(Grant No.51827811)the National Natural Science Foundation of China,(Grant No.52008141)the Shenzhen Technology Innovation Program(Grant Nos.JCYJ20170811160003571,JCYJ20180508152238111 and JCYJ20200109112803851).
文摘Collisions between a moving mass and an anti-collision device increase structural responses and threaten structural safety.An active mass damper(AMD)with stroke limitations is often used to avoid collisions.However,a strokelimited AMD control system with a fixed limited area shortens the available AMD stroke and leads to significant control power.To solve this problem,the design approach with variable gain and limited area(VGLA)is proposed in this study.First,the boundary of variable-limited areas is calculated based on the real-time status of the moving mass.The variable gain(VG)expression at the variable limited area is deduced by considering the saturation of AMD stroke.Then,numerical simulations of a stroke-limited AMD control system with VGLA are conducted on a high-rise building structure.These numerical simulations show that the proposed approach has superior strokelimitation performance compared with a stroke-limited AMD control system with a fixed limited area.Finally,the proposed approach is validated through experiments on a four-story steel frame.
基金supported by the Natural Science Foundation of China(52122811)。
文摘To enable the experimental assessment of the seismic performance of full-scale nonstructural elements with multiple engineering parameters(EDPs),a three-layer testbed named Nonstructural Element Simulator on Shake Table(NEST)has been developed.The testbed consists of three consecutive floors of steel structure.The bottom two floors provide a space to accommodate a full-scale room.To fully explore the flexibility of NEST,we propose a novel control strategy to generate the required shake table input time histories for the testbed to track the target floor motions of the buildings of interest with high accuracy.The control strategy contains two parts:an inverse dynamic compensation via simulation of feedback control systems(IDCS)algorithm and an offline iteration procedure based on a refined nonlinear numerical model of the testbed.The key aspects of the control strategy were introduced in this paper.Experimental tests were conducted to simulate the seismic responses of a full-scale office room on the 21^(st)floor of a 42-story high-rise building.The test results show that the proposed control strategy can reproduce the target floor motions of the building of interest with less than 20%errors within the specified frequency range.
基金supported by the National Natural Science Foundation of China (Grant No. 90815025)the Tsinghua University Research Funds (Grant No. 2010THZ02-1)the "Program for New Century Excellent Talents in University"
文摘In recent years, super high-rise buildings (>500 m) are developing very quickly and become an important frontier of civil engineering. The collapse resistance of super high-rise buildings subjected to extremely strong earthquake is a critical problem that must be intensively studied. This paper builds up a nonlinear finite element model of the tallest building in China, Shang- hai Tower (632 m), and proposes the modeling method and failure criteria for different structural elements. The dynamic char- acters of this building are then analyzed, and the possible failure modes and collapse processes due to earthquakes are pre- dicted, as well as the corresponding collapse mechanism. This work will be helpful in collapse prevention and the seismic design of super high-rise buildings.
基金supported by "Twelfth Five-Year" plan major projects supported by National Science and Technology (Grant No.2011BAJ09B01)the National Nature Science Foundation of China (Grant Nos. 51222804, 51261120377)+1 种基金the Tsinghua University Initiative Scientific Research Program (Grant Nos. 2012THZ02-2, 2011THZ03) the Fok Ying Dong Education Foundation (Grant No. 131071)
文摘Ground motion intensity measure (IM) is an important part in performance-based seismic design. A reasonable and efficient IM can make the prediction of the structural seismic responses more accurate. Therefore, a more reasonable IM for super high-rise buildings is proposed in this paper. This IM takes into account the significant characteristic that higher-order vibration modes play important roles in the seismic response of super high-rise buildings, as well as the advantages of some existing IMs. The key parameter of the proposed IM is calibrated using a series of time-history analyses. The collapse simulations of two super high-rise buildings are used to discuss the suitability of the proposed IM and some other existing IMs. The results indicate that the proposed IM yields a smaller coefficient of variation for the critical collapse status than other existing IMs and performs well in reflecting the contribution of higher-order vibration modes to the structural response. Hence, the proposed IM is more applicable to seismic design for super high-rise buildings than other IMs.
文摘旨在分析子午岭黑山羊的群体遗传多样性和亲缘关系以及家系结构,为子午岭黑山羊的保护和利用提供依据。本研究通过简化基因组测序(super-genotyping by sequencing,Super-GBS)技术对99只(10公/89母)成年子午岭黑山羊进行全基因组SNP检测。利用Plink软件计算观测杂合度(Ho)、期望杂合度(He)、多态信息含量(PIC)、核苷酸多样性(Pi)、有效等位基因数(Ne)及次要等位基因频率(MAF)等6项遗传多样性指标;GCTA软件进行主成分分析及基因组亲缘关系G矩阵构建;Plink软件构建IBS遗传距离矩阵,R语言绘制热图;PHYLP构建系统发育树;detect RUNS工具检测ROH。结果表明,99只子午岭黑山羊个体共检测到996042个SNPs。子午岭黑山羊群体的PIC、Pi、Ne及MAF值分别是0.161、0.193、1.295、0.130,且Ho(0.167)低于He(0.192),说明子午岭黑山羊群体遗传多样性较低。G矩阵和IBS遗传距离结果均表明子午岭黑山羊群体间大部分个体间亲缘关系较远。主成分分析结果揭示子午岭黑山羊群体内部不存在明显分化,系统发育树结果说明子午岭黑山羊群体公羊可大致分为6个家系,所有家系公羊数量较少。子午岭黑山羊群体的近交系数FROH为0.0496,说明子午岭黑山羊群体内部近交程度相对较低。综上所述,子午岭黑山羊群体遗传多样性较低,大部分个体间亲缘关系较远,群体内近交程度较低,后期应注意后代的选育,避免血统流失。
文摘Cost overrun is a common problem in construction projects worldwide.Most Indian construction projects,particularly those involving high-rise buildings,have had severe cost overruns.For managers,architects,engineers,and contractors,completing building projects within the specified cost budget has become the most important and hard assignment.Since it is common for high-rise building projects to go over budget,the aim of this study is to find out the causes of cost overruns and provide effective measures.The study found 70 cost overrun factors based on a comprehensive literature review and expert opinions.A Google form questionnaire was distributed to 150 construction professionals across India.After following up,101 of the 150 responses were received.A five-point Likert scale was used and the acquired data was analyzed and ranked using the Relative Importance Index(RII)technique.According to the findings of RII,the top ten critical factors influencing cost overruns were frequent change orders during construction by the owner,delay in construction,escalation of material prices,market inflation or deflation,rework,frequent changes in design,inaccurate evaluation of the project timeline,unforeseen ground condition,inaccurate quantity take-off,and delay in progressive payment by the owner.Spearman’s rank correlation test revealed that there is a very significant relationship between the rankings of factors provided by the owner,the consultant,and the contractor.In addition,a factor analysis tool in the SPSS software was also used to categorize the seventy factors into sixteen core components.The top ten critical factors were presented to subject matter experts,and their suggestions were being compiled.These results are expected to help construction professionals minimize cost overruns,improve cost control measures,and initiate future research.
基金the TCL Science and Technology Innovation Fundthe Youth Science and Technology Talent Promotion Project of Jiangsu Association for Science and Technology,Grant/Award Number:JSTJ‐2023‐017+4 种基金Shenzhen Municipal Science and Technology Innovation Council,Grant/Award Number:JSGG20220831105002004National Natural Science Foundation of China,Grant/Award Number:62201468Postdoctoral Research Foundation of China,Grant/Award Number:2022M722599the Fundamental Research Funds for the Central Universities,Grant/Award Number:D5000210966the Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2021A1515110079。
文摘Convolutional neural networks depend on deep network architectures to extract accurate information for image super‐resolution.However,obtained information of these con-volutional neural networks cannot completely express predicted high‐quality images for complex scenes.A dynamic network for image super‐resolution(DSRNet)is presented,which contains a residual enhancement block,wide enhancement block,feature refine-ment block and construction block.The residual enhancement block is composed of a residual enhanced architecture to facilitate hierarchical features for image super‐resolution.To enhance robustness of obtained super‐resolution model for complex scenes,a wide enhancement block achieves a dynamic architecture to learn more robust information to enhance applicability of an obtained super‐resolution model for varying scenes.To prevent interference of components in a wide enhancement block,a refine-ment block utilises a stacked architecture to accurately learn obtained features.Also,a residual learning operation is embedded in the refinement block to prevent long‐term dependency problem.Finally,a construction block is responsible for reconstructing high‐quality images.Designed heterogeneous architecture can not only facilitate richer structural information,but also be lightweight,which is suitable for mobile digital devices.Experimental results show that our method is more competitive in terms of performance,recovering time of image super‐resolution and complexity.The code of DSRNet can be obtained at https://github.com/hellloxiaotian/DSRNet.
文摘The sol-gel method is used to prepare a new nano-alumina aerogel structure and the thermal properties of this nanomaterial are investigated comprehensively using electron microscope scanning,thermal analysis,X-ray and infrared spectrometer analysis methods.It is found that the composite aerogel alumina material has a multi-level porous nano-network structure.When employed for the thermal insulation of high-rise buildings,the alumina nanocomposite aerogel material can lead to effective energy savings in winter.However,it has almost no energy-saving effect on buildings where energy is consumed for cooling in summer.
基金Supported by National Key R&D Programs of China,No.2022YFC2503600.
文摘The top goal of modern medicine is treating disease without destroying organ structures and making patients as healthy as they were before their sickness.Minimally invasive surgery(MIS)has dominated the surgical realm because of its lesser invasiveness.However,changes in anatomical structures of the body and reconstruction of internal organs or different organs are common after traditional surgery or MIS,decreasing the quality of life of patients post-operation.Thus,I propose a new treatment mode,super MIS(SMIS),which is defined as“curing a disease or lesion which used to be treated by MIS while preserving the integrity of the organs”.In this study,I describe the origin,definition,operative channels,advantages,and future perspectives of SMIS.