This study focuses on reconstructing the"reader-centered"paradigm in the teaching of high school English literary text reading,supported by Reception Aesthetics as its theoretical foundation.High school Engl...This study focuses on reconstructing the"reader-centered"paradigm in the teaching of high school English literary text reading,supported by Reception Aesthetics as its theoretical foundation.High school English literary text reading plays a significant role in cultivating students'language proficiency,cultural awareness,and aesthetic literacy.However,the current teaching practice in this area remains dominated by the traditional"teacher-centered"approach,which restricts students'active participation and the realization of the pluralistic value of literary texts.By integrating core concepts of Reception Aesthetics-such as"horizon of expectations,""structure of appeal,"and"interpretive community"-this research addresses the gap in existing studies,which have largely focused on the application of Reception Aesthetics in Chinese language teaching or college English instruction.Using literature research and classroom practice analysis,the study reconstructs the"reader-centered"paradigm across three dimensions:teaching objectives,teaching process,and evaluation methods.It also identifies practical challenges,including uneven student participation,time constraints,and difficulties in the teacher's role adaptation,and proposes corresponding optimization strategies.Practical results demonstrate that this paradigm effectively enhances students'reading engagement,text interpretation skills,and critical thinking.Future research may further expand text types and integrate information technology to continuously improve teaching effectiveness.展开更多
With the rapid growth of cloud computing,the number of data centers(DCs)continuously increases,leading to a high-energy consumption dilemma.Cooling,apart from IT equipment,represents the largest energy consumption in ...With the rapid growth of cloud computing,the number of data centers(DCs)continuously increases,leading to a high-energy consumption dilemma.Cooling,apart from IT equipment,represents the largest energy consumption in DCs.Passive design(PD)and active design(AD)are two important approaches in architectural design to reduce energy consumption.However,for DC cooling,few studies have summarized AD,and there are almost no studies on PD.Based on existing international research(2005-2024),this paper summarizes the current state of cooling strategies for DCs.PD encompasses floors,ceilings,and layout and zoning of racks.Additionally,other passive strategies not yet studied in DCs are critically examined.AD includes air,liquid,free,and two-phase cooling.This paper systematically compares the performance of different AD technologies on various KPIs,including energy,economic,and environmental indicators.This paper also explores the application of different cooling design strategies through best-practice examples and presents advanced algorithms for energy management in operational DCs.This study reveals that free cooling is widely employed,with Artificial Neural Networks emerging as the most popular algorithm for managing cooling energy.Finally,this paper suggests four future directions for reducing cooling energy in DCs,with a focus on the development of passive strategies.This paper provides an overview and guide to DC energy-consumption issues,emphasizes the importance of implementing passive and active design strategies to reduce DC cooling energy consumption,and provides directions and references for future energy-efficient DC designs.展开更多
Organic-inorganic metal halides(OIMHs)have emerged as highly promising novel multifunctional optoelectronic materials,owing to their easily adjustable properties from a variety of combinations of different components....Organic-inorganic metal halides(OIMHs)have emerged as highly promising novel multifunctional optoelectronic materials,owing to their easily adjustable properties from a variety of combinations of different components.But it is still difficult and rare to realize highly tunable multicolor luminescence within the same material.In this work,we successfully incorporated three adjustable emission centers in OIMHs to synthesize a novel OIMH(NEA)_(2)MnBr_(4),with each emission center capable of emitting one of the primary colors—red,green,and blue.The green and red emissions originate from the tetrahedron and octahedron structures in the Mn-based frame,while the blue can be attributed to the contribution of organic components.Additionally,to achieve comparable emission intensity among the three primary colors,we enhanced the blue emission performance by optimizing the ratio of organic structure components and incorporating chirality in the OIMHs.The resulting high-quality films can be obtained by spin-coating method with a photoluminescence quantum yields of up to 96%.More interestingly,by the dual manipulation of excitation wavelength and temperature,the sample can be emitted at least seven distinct colors including a standard white luminescence at(0.33,0.33),opening up promising prospects for multicolor luminescence applications such as high-end anti-counterfeiting technology,light-emitting diodes,X-ray imaging,latent fingerprints,humidity detection,and so on.Therefore,based on application scenarios and requirements,our research on this highly tunable luminescent OIMH material lays a solid foundation for further development of various functional properties of related materials.展开更多
The Mountain Science Data Center(MSDC),founded in 2021 under the Institute of Mountain Hazards and Environment(IMHE),Chinese Academy of Sciences,manages the entire lifecycle of mountain science data.It integrates data...The Mountain Science Data Center(MSDC),founded in 2021 under the Institute of Mountain Hazards and Environment(IMHE),Chinese Academy of Sciences,manages the entire lifecycle of mountain science data.It integrates data from diverse sources,including debris flows,landslides,soils,ecology,geology,natural resources,basic geographic information,and socio-economic data.The center provides comprehensive services,including data collection,processing,analysis tools,modeling,and application support,offering reliable data backing for numerous research projects within the institute.Data management and services are accessible via the Mountain Science Data Center Portal(https://www.msdc.ac.cn/),ensuring long-term,stable,and trustworthy access to facilitate scientific research and institutional development.展开更多
Rapid developments in the electronic information industry drive the increased energy usage and carbon emission of data center buildings,prompting the focus on the energy efficiency and environmental sustainability.Exp...Rapid developments in the electronic information industry drive the increased energy usage and carbon emission of data center buildings,prompting the focus on the energy efficiency and environmental sustainability.Expanded operation envelopes of tropical data centers is assessed to analyze the potential for the building energy savings and carbon emission reduction through collaborative analysis of operation modes(OMs),supply air temperature(SAT),and outdoor air temperature(OAT).The OMs of compression vary with the setpoints of SAT,in which the average exergy efficiency of compressors at alternate operation mode is 6.8%and 8.0%lower than that of double and single compression operations.As SAT rises from 20℃to 32℃,the system exergoeconomic factor increases from 5.4%to 8.0%,and the average carbon cost decreases by 36.5%.Additionally,with just an 8.5%increase in exergy cost(i.e.,Case 8)at OAT rising from 30 to 34℃,the high SAT and low refrigerant charges provide considerable exergy cost advantages versus resisting the OAT fluctuations.Dynamic operation strategies are also proposed and compared to cope with the impacts of tropical environments.Compared to the 26℃SAT baseline,the average energy savings are 9.1-14.7%,indicating the ability to fully utilize outdoor and indoor conditions.展开更多
The 20th Communist Party of China(CPC)Central Committee held its fourth plenary session in Beijing on October 20-23.The plenary session's central task was to deliberate on the framework of the country's next n...The 20th Communist Party of China(CPC)Central Committee held its fourth plenary session in Beijing on October 20-23.The plenary session's central task was to deliberate on the framework of the country's next national development roadmap:the 15th Five-Year Plan(2026-2030).Every five-year plan is important but this one arrives at a truly pivotal moment in terms of China's development trajectory and the global environment.展开更多
In this paper,we present an extrapolated parallel subgradient projection method with the centering technique for the convex feasibility problem,the algorithm improves the convergence by reason of using centering techn...In this paper,we present an extrapolated parallel subgradient projection method with the centering technique for the convex feasibility problem,the algorithm improves the convergence by reason of using centering techniques which reduce the oscillation of the corresponding sequence.To prove the convergence in a simply way,we transmit the parallel algorithm in the original space to a sequential one in a newly constructed product space.Thus,the convergence of the parallel algorithm is derived with the help of the sequential one under some suitable conditions.Numerical results show that the new algorithm has better convergence than the existing algorithms.展开更多
A new type of beam-to-column connection for steel moment flames, designated as a ＂self-centering connection,＂ is studied. In this connection, bolted top-and-seat angles, and post-tensioned （PT） high-strength steel...A new type of beam-to-column connection for steel moment flames, designated as a ＂self-centering connection,＂ is studied. In this connection, bolted top-and-seat angles, and post-tensioned （PT） high-strength steel strands running along the beam are used. The PT strands tie the beam flanges on the column flange to resist moment and provide self-centering force. After an earthquake, the connections have zero deformation, and can be restored to their original status by simply replacing the angles. Four full-scale connections were tested under cyclic loading. The strength, energy-dissipation capacity, hysteresis curve, as well as angles and PT strands behavior of the connections are investigated. A general FEM analysis program called ABAQUS 6.9 is adopted to model the four test specimens. The numerical and test results match very well. Both the test and analysis results suggest that： （1） the columns and beams remain elastic while the angles sustain plastic deformations for energy dissipation when the rotation of the beam related to the column equals 0.05 tad, （2） the energy dissipation capacity is enhanced when the thickness of the angle is increased, and （3） the number of PT strands has a significant influence on the behavior of the connections, whereas the distance between the strands is not as important to the performance of the connection.展开更多
Multicollinearity constitutes shared variation among predictors that inflates standard errors of regression coefficients. Several years ago, it was proven that the common practice of mean centering in moderated regres...Multicollinearity constitutes shared variation among predictors that inflates standard errors of regression coefficients. Several years ago, it was proven that the common practice of mean centering in moderated regression cannot alleviate multicollinearity among variables comprising an interaction, but merely masks it. Residual centering (orthogonalizing) is unacceptable because it biases parameters for predictors from which the interaction derives, thus precluding interpretation of moderator effects. I propose and validate residual centering in sequential re-estimations of a moderated regression—sequential residual centering (SRC)—by revealing unbiased multicollinearity conditioning across the interaction and its related terms. Across simulations, SRC reduces variance inflation factors (VIF) regardless of distribution shape or pattern of regression coefficients across predictors. For any predictor, the reduced VIF is used to derive a lower standard error of its regression coefficient. A cancer sample illustrates SRC, which allows unbiased interpretations of symptom clusters. SRC can be applied efficiently to alleviate multicollinearity after data collection and shows promise for advancing synergistic frontiers of research.展开更多
By means of programs GTMPAC based- on generalized triangle method,analysis and synthesis of mechanism design in accordance with absolutely graphicalmethod( absolutely germetrical method) are developed.In this paper,we...By means of programs GTMPAC based- on generalized triangle method,analysis and synthesis of mechanism design in accordance with absolutely graphicalmethod( absolutely germetrical method) are developed.In this paper,we make aspecial study about centering- point curve and circling- point curve and couplercurves based on Ball’s points.展开更多
The effects of centering response and explanatory variables as a way of simplifying fitted linear models in the presence of correlation are reviewed and extended to include nonlinear models, common in many biological ...The effects of centering response and explanatory variables as a way of simplifying fitted linear models in the presence of correlation are reviewed and extended to include nonlinear models, common in many biological and economic applications. In a nonlinear model, the use of a local approximation can modify the effect of centering. Even in the presence of uncorrelated explanatory variables, centering may affect linear approximations and related test statistics. An approach to assessing this effect in relation to intrinsic curvature is developed and applied. Mis-specification bias of linear versus nonlinear models also reflects this centering effect.展开更多
The seismic performance of a self-centering precast reinforced concrete （RC） frame with shear walls was investigated in this paper. The lateral force resistance was provided by self-centering precast RC shear walls ...The seismic performance of a self-centering precast reinforced concrete （RC） frame with shear walls was investigated in this paper. The lateral force resistance was provided by self-centering precast RC shear walls （SPCW）, which utilize a combination ofunbonded prestressed post-tensioned （PT） tendons and mild steel reinforcing bars for flexural resistance across base joints. The structures concentrated deformations at the bottom joints and the unbonded PT tendons provided the self-centering restoring force. A 1/3-scale model of a five-story self-centering RC frame with shear walls was designed and tested on a shake-table under a series of bi-directional earthquake excitations with increasing intensity. The acceleration response, roof displacement, inter-story drifts, residual drifts, shear force ratios, hysteresis curves, and local behaviour of the test specimen were analysed and evaluated. The results demonstrated that seismic performance of the test specimen was satisfactory in the plane of the shear wall; however, the structure sustained inter-story drift levels up to 2.45%. Negligible residual drifts were recorded after all applied earthquake excitations. Based on the shake-table test results, it is feasible to apply and popularize a self-centering precast RC frame with shear walls as a structural system in seismic regions.展开更多
This paper presents the results of a parametric study of self-centering seismic retrofit schemes for reinforced concrete (RC) frame buildings. The self-centering retrofit system features flag-shaped hysteresis and min...This paper presents the results of a parametric study of self-centering seismic retrofit schemes for reinforced concrete (RC) frame buildings. The self-centering retrofit system features flag-shaped hysteresis and minimal residual deformation. For comparison purpose,an alternate seismic retrofit scheme that uses a bilinear-hysteresis retrofit system such as buckling-restrained braces (BRB) is also considered in this paper. The parametric study was carried out in a single-degree-of-freedom (SDOF) system framework since a multi-story building structure may be idealized as an equivalent SDOF system and investigation of the performance of this equivalent SDOF system can provide insight into the seismic response of the multi-story building. A peak-oriented hysteresis model which can consider the strength and stiffness degradation is used to describe the hysteretic behavior of RC structures. The parametric study involves two key parameters -the strength ratio and elastic stiffness ratio between the seismic retrofit system and the original RC frame. An ensemble of 172 earthquake ground motion records scaled to the design basis earthquake in California with a probability of exceedance of 10% in 50 years was constructed for the simulation-based parametric study. The effectiveness of the two seismic retrofit schemes considered in this study is evaluated in terms of peak displacement ratio,peak acceleration ratio,energy dissipation demand ratio and residual displacement ratio between the SDOF systems with and without retrofit. It is found from this parametric study that RC structures retrofitted with the self-centering retrofit scheme (SCRS) can achieve a seismic performance level comparable to the bilinear-hysteresis retrofit scheme (BHRS) in terms of peak displacement and energy dissipation demand ratio while having negligible residual displacement after earthquake.展开更多
Firstly, in view of the respective defects of existing self-centering devices for vehicle suspension height, the design scheme of the proposed mechanical self-centering device for suspension height is described. Takin...Firstly, in view of the respective defects of existing self-centering devices for vehicle suspension height, the design scheme of the proposed mechanical self-centering device for suspension height is described. Taking the rear suspension of a certain light bus as a research example, the structures and parameters of the novel device are designed and ascertained. Then, the road excitation models, the performance evaluation indexes and the half-vehicle model are built, the simulation outputs of time and frequency domain are obtained with the road excitations of random and pulse by using MATLAB/Simulink software. So the main characteristics of the self-centering suspension are presented preliminarily. Finally, a multi-objective parameter design optimization model for the self-centering device is built by weighted sum approach, and optimal solution is obtained by adopting complex approach. The relevant choosing-type parameters for self-centering device components are deduced by using discrete variable optimal method, and the optimal results are verified and analyzed. So the performance potentials of the self-centering device are exerted fully in condition of ensuring overall suspension performances.展开更多
Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during ...Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during the rocking process.An innovative RW with a curved interface is proposed to prevent interfacial corners from producing local damage,enhancing its earthquake resilient performance(ERP).The precast wall panel with a curved interface is assembled into an integral self-centering hybrid rocking wall(SCRW)by two post-tensioned unbonded prestressed tendons.Moreover,two ordinary energy dissipation steel rebars and two shear reinforcements are arranged to increase the energy dissipation capacity and lateral resistance.Two SCRW specimens and one monolithic reinforced concrete(RC)shear wall(SW)were tested under pseudo-static loading to compare the ERPs of the proposed SCRW and the SW,focusing on studying the effect of the curved interface on the SCRW.The key resilient performance of rocking effects,failure modes,and hysteretic properties of the SCRW were explored.The results show that nonlinear deformations of the SCRW are concentrated along the interface between the SCRW and the foundation,avoiding damage within the SCRW.The restoring force provided by the prestressed tendons can effectively realize self-centering capacity with small residual deformation,and the resilient performance of the SCRW is better than that of monolithic SW.In addition,the curved interface of the SCRW makes the rocking center change and move inward,partially relieving the stress concentration and crush of concrete.The rocking range of the rocking center is about 41.4%of the width of the SCRW.展开更多
A new type of steel moment resisting frame with bottom flange friction devices （BFFDs） has been developed to provide self-centering capacity and energy dissipation, and to reduce permanent deformations under earthqu...A new type of steel moment resisting frame with bottom flange friction devices （BFFDs） has been developed to provide self-centering capacity and energy dissipation, and to reduce permanent deformations under earthquakes. This paper presents a numerical simulation of self-centering beam-column connections with BFFDs, in which the gap opening/closing at the beam-column interfaces is simulated by using pairs of zero-length elements with compression-only material properties, and the energy dissipation due to friction is simulated by using truss elements with specified hysteretic behavior. In particular, the effect of the friction bolt bearing against the slotted plate in the BFFDs was modeled, so that the increase in lateral force and the loss of friction force due to the bolt bearing could be taken into account. Parallel elastic-perfectly plastic gap （ElasticPPGap） materials in the Open System for Earthquake Engineering Simulation （OpenSees） were used with predefined gaps to specify the sequence that each bolt went into the bearing and the corresponding increase in bending stiffness. The MinMax material in OpenSees is used to specify the minimum and maximum values of strains of the ElasticPPGap materials. To consider the loss of friction force due to bok bearing, a number of parallel hysteretic materials were used, and the failure of these materials in sequence simulated the gradual loss of friction force. Analysis results obtained by using the proposed numerical model are discussed and compared with the test results under cyclic loadings and the seismic loading, respectively.展开更多
Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical neuroepithelium.One such signaling center is the cortical hem,...Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical neuroepithelium.One such signaling center is the cortical hem,which arises during embryonic development at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the developmental roles of the cortical hem is derived from the analysis in mice.The cortical hem produces several types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)proteins.The cortical hem is particularly important for the development of the hippocampus,which is involved in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behavior and higher cognitive functions(Mangale et al.,2008;Dal-Valle-Anton and Borrell,2022).展开更多
Air pollution in China covers a large area with complex sources and formation mechanisms,making it a unique place to conduct air pollution and atmospheric chemistry research.The National Natural Science Foundation of ...Air pollution in China covers a large area with complex sources and formation mechanisms,making it a unique place to conduct air pollution and atmospheric chemistry research.The National Natural Science Foundation of China’s Major Research Plan entitled“Fundamental Researches on the Formation and Response Mechanism of the Air Pollution Complex in China”(or the Plan)has funded 76 research projects to explore the causes of air pollution in China,and the key processes of air pollution in atmospheric physics and atmospheric chemistry.In order to summarize the abundant data from the Plan and exhibit the long-term impacts domestically and internationally,an integration project is responsible for collecting the various types of data generated by the 76 projects of the Plan.This project has classified and integrated these data,forming eight categories containing 258 datasets and 15 technical reports in total.The integration project has led to the successful establishment of the China Air Pollution Data Center(CAPDC)platform,providing storage,retrieval,and download services for the eight categories.This platform has distinct features including data visualization,related project information querying,and bilingual services in both English and Chinese,which allows for rapid searching and downloading of data and provides a solid foundation of data and support for future related research.Air pollution control in China,especially in the past decade,is undeniably a global exemplar,and this data center is the first in China to focus on research into the country’s air pollution complex.展开更多
文摘This study focuses on reconstructing the"reader-centered"paradigm in the teaching of high school English literary text reading,supported by Reception Aesthetics as its theoretical foundation.High school English literary text reading plays a significant role in cultivating students'language proficiency,cultural awareness,and aesthetic literacy.However,the current teaching practice in this area remains dominated by the traditional"teacher-centered"approach,which restricts students'active participation and the realization of the pluralistic value of literary texts.By integrating core concepts of Reception Aesthetics-such as"horizon of expectations,""structure of appeal,"and"interpretive community"-this research addresses the gap in existing studies,which have largely focused on the application of Reception Aesthetics in Chinese language teaching or college English instruction.Using literature research and classroom practice analysis,the study reconstructs the"reader-centered"paradigm across three dimensions:teaching objectives,teaching process,and evaluation methods.It also identifies practical challenges,including uneven student participation,time constraints,and difficulties in the teacher's role adaptation,and proposes corresponding optimization strategies.Practical results demonstrate that this paradigm effectively enhances students'reading engagement,text interpretation skills,and critical thinking.Future research may further expand text types and integrate information technology to continuously improve teaching effectiveness.
文摘With the rapid growth of cloud computing,the number of data centers(DCs)continuously increases,leading to a high-energy consumption dilemma.Cooling,apart from IT equipment,represents the largest energy consumption in DCs.Passive design(PD)and active design(AD)are two important approaches in architectural design to reduce energy consumption.However,for DC cooling,few studies have summarized AD,and there are almost no studies on PD.Based on existing international research(2005-2024),this paper summarizes the current state of cooling strategies for DCs.PD encompasses floors,ceilings,and layout and zoning of racks.Additionally,other passive strategies not yet studied in DCs are critically examined.AD includes air,liquid,free,and two-phase cooling.This paper systematically compares the performance of different AD technologies on various KPIs,including energy,economic,and environmental indicators.This paper also explores the application of different cooling design strategies through best-practice examples and presents advanced algorithms for energy management in operational DCs.This study reveals that free cooling is widely employed,with Artificial Neural Networks emerging as the most popular algorithm for managing cooling energy.Finally,this paper suggests four future directions for reducing cooling energy in DCs,with a focus on the development of passive strategies.This paper provides an overview and guide to DC energy-consumption issues,emphasizes the importance of implementing passive and active design strategies to reduce DC cooling energy consumption,and provides directions and references for future energy-efficient DC designs.
基金supported by supported by the Basic Research Project of State Key Laboratory of Photovoltaic Science and Technology(No.202401020302)funding support from the National Natural Science Foundation of China(No.62274040 and No.62304046)Shanghai science and technology innovation action plan(No.24DZ3001200)。
文摘Organic-inorganic metal halides(OIMHs)have emerged as highly promising novel multifunctional optoelectronic materials,owing to their easily adjustable properties from a variety of combinations of different components.But it is still difficult and rare to realize highly tunable multicolor luminescence within the same material.In this work,we successfully incorporated three adjustable emission centers in OIMHs to synthesize a novel OIMH(NEA)_(2)MnBr_(4),with each emission center capable of emitting one of the primary colors—red,green,and blue.The green and red emissions originate from the tetrahedron and octahedron structures in the Mn-based frame,while the blue can be attributed to the contribution of organic components.Additionally,to achieve comparable emission intensity among the three primary colors,we enhanced the blue emission performance by optimizing the ratio of organic structure components and incorporating chirality in the OIMHs.The resulting high-quality films can be obtained by spin-coating method with a photoluminescence quantum yields of up to 96%.More interestingly,by the dual manipulation of excitation wavelength and temperature,the sample can be emitted at least seven distinct colors including a standard white luminescence at(0.33,0.33),opening up promising prospects for multicolor luminescence applications such as high-end anti-counterfeiting technology,light-emitting diodes,X-ray imaging,latent fingerprints,humidity detection,and so on.Therefore,based on application scenarios and requirements,our research on this highly tunable luminescent OIMH material lays a solid foundation for further development of various functional properties of related materials.
文摘The Mountain Science Data Center(MSDC),founded in 2021 under the Institute of Mountain Hazards and Environment(IMHE),Chinese Academy of Sciences,manages the entire lifecycle of mountain science data.It integrates data from diverse sources,including debris flows,landslides,soils,ecology,geology,natural resources,basic geographic information,and socio-economic data.The center provides comprehensive services,including data collection,processing,analysis tools,modeling,and application support,offering reliable data backing for numerous research projects within the institute.Data management and services are accessible via the Mountain Science Data Center Portal(https://www.msdc.ac.cn/),ensuring long-term,stable,and trustworthy access to facilitate scientific research and institutional development.
基金supported by the National Research Foundation,Singapore,funded under Energy Research Testbed and Industry Partnership Funding Initiative,part of the Energy Grid(EG)2.0 programme.
文摘Rapid developments in the electronic information industry drive the increased energy usage and carbon emission of data center buildings,prompting the focus on the energy efficiency and environmental sustainability.Expanded operation envelopes of tropical data centers is assessed to analyze the potential for the building energy savings and carbon emission reduction through collaborative analysis of operation modes(OMs),supply air temperature(SAT),and outdoor air temperature(OAT).The OMs of compression vary with the setpoints of SAT,in which the average exergy efficiency of compressors at alternate operation mode is 6.8%and 8.0%lower than that of double and single compression operations.As SAT rises from 20℃to 32℃,the system exergoeconomic factor increases from 5.4%to 8.0%,and the average carbon cost decreases by 36.5%.Additionally,with just an 8.5%increase in exergy cost(i.e.,Case 8)at OAT rising from 30 to 34℃,the high SAT and low refrigerant charges provide considerable exergy cost advantages versus resisting the OAT fluctuations.Dynamic operation strategies are also proposed and compared to cope with the impacts of tropical environments.Compared to the 26℃SAT baseline,the average energy savings are 9.1-14.7%,indicating the ability to fully utilize outdoor and indoor conditions.
文摘The 20th Communist Party of China(CPC)Central Committee held its fourth plenary session in Beijing on October 20-23.The plenary session's central task was to deliberate on the framework of the country's next national development roadmap:the 15th Five-Year Plan(2026-2030).Every five-year plan is important but this one arrives at a truly pivotal moment in terms of China's development trajectory and the global environment.
基金Supported by the NNSF of china(11171221)SuppoSed by the Shanghai Municipal Committee of Science and Technology(10550500800)
文摘In this paper,we present an extrapolated parallel subgradient projection method with the centering technique for the convex feasibility problem,the algorithm improves the convergence by reason of using centering techniques which reduce the oscillation of the corresponding sequence.To prove the convergence in a simply way,we transmit the parallel algorithm in the original space to a sequential one in a newly constructed product space.Thus,the convergence of the parallel algorithm is derived with the help of the sequential one under some suitable conditions.Numerical results show that the new algorithm has better convergence than the existing algorithms.
基金National Natural Science Foundation of China under Nos.50808107,51178250 and 51261120377
文摘A new type of beam-to-column connection for steel moment flames, designated as a ＂self-centering connection,＂ is studied. In this connection, bolted top-and-seat angles, and post-tensioned （PT） high-strength steel strands running along the beam are used. The PT strands tie the beam flanges on the column flange to resist moment and provide self-centering force. After an earthquake, the connections have zero deformation, and can be restored to their original status by simply replacing the angles. Four full-scale connections were tested under cyclic loading. The strength, energy-dissipation capacity, hysteresis curve, as well as angles and PT strands behavior of the connections are investigated. A general FEM analysis program called ABAQUS 6.9 is adopted to model the four test specimens. The numerical and test results match very well. Both the test and analysis results suggest that： （1） the columns and beams remain elastic while the angles sustain plastic deformations for energy dissipation when the rotation of the beam related to the column equals 0.05 tad, （2） the energy dissipation capacity is enhanced when the thickness of the angle is increased, and （3） the number of PT strands has a significant influence on the behavior of the connections, whereas the distance between the strands is not as important to the performance of the connection.
文摘Multicollinearity constitutes shared variation among predictors that inflates standard errors of regression coefficients. Several years ago, it was proven that the common practice of mean centering in moderated regression cannot alleviate multicollinearity among variables comprising an interaction, but merely masks it. Residual centering (orthogonalizing) is unacceptable because it biases parameters for predictors from which the interaction derives, thus precluding interpretation of moderator effects. I propose and validate residual centering in sequential re-estimations of a moderated regression—sequential residual centering (SRC)—by revealing unbiased multicollinearity conditioning across the interaction and its related terms. Across simulations, SRC reduces variance inflation factors (VIF) regardless of distribution shape or pattern of regression coefficients across predictors. For any predictor, the reduced VIF is used to derive a lower standard error of its regression coefficient. A cancer sample illustrates SRC, which allows unbiased interpretations of symptom clusters. SRC can be applied efficiently to alleviate multicollinearity after data collection and shows promise for advancing synergistic frontiers of research.
文摘By means of programs GTMPAC based- on generalized triangle method,analysis and synthesis of mechanism design in accordance with absolutely graphicalmethod( absolutely germetrical method) are developed.In this paper,we make aspecial study about centering- point curve and circling- point curve and couplercurves based on Ball’s points.
文摘The effects of centering response and explanatory variables as a way of simplifying fitted linear models in the presence of correlation are reviewed and extended to include nonlinear models, common in many biological and economic applications. In a nonlinear model, the use of a local approximation can modify the effect of centering. Even in the presence of uncorrelated explanatory variables, centering may affect linear approximations and related test statistics. An approach to assessing this effect in relation to intrinsic curvature is developed and applied. Mis-specification bias of linear versus nonlinear models also reflects this centering effect.
基金National Natural Science Foundation of China(NSFC)under Grant Nos.51638012 and 51578401
文摘The seismic performance of a self-centering precast reinforced concrete （RC） frame with shear walls was investigated in this paper. The lateral force resistance was provided by self-centering precast RC shear walls （SPCW）, which utilize a combination ofunbonded prestressed post-tensioned （PT） tendons and mild steel reinforcing bars for flexural resistance across base joints. The structures concentrated deformations at the bottom joints and the unbonded PT tendons provided the self-centering restoring force. A 1/3-scale model of a five-story self-centering RC frame with shear walls was designed and tested on a shake-table under a series of bi-directional earthquake excitations with increasing intensity. The acceleration response, roof displacement, inter-story drifts, residual drifts, shear force ratios, hysteresis curves, and local behaviour of the test specimen were analysed and evaluated. The results demonstrated that seismic performance of the test specimen was satisfactory in the plane of the shear wall; however, the structure sustained inter-story drift levels up to 2.45%. Negligible residual drifts were recorded after all applied earthquake excitations. Based on the shake-table test results, it is feasible to apply and popularize a self-centering precast RC frame with shear walls as a structural system in seismic regions.
基金Univeristy of Maryland,Start-up Grant to the First Author
文摘This paper presents the results of a parametric study of self-centering seismic retrofit schemes for reinforced concrete (RC) frame buildings. The self-centering retrofit system features flag-shaped hysteresis and minimal residual deformation. For comparison purpose,an alternate seismic retrofit scheme that uses a bilinear-hysteresis retrofit system such as buckling-restrained braces (BRB) is also considered in this paper. The parametric study was carried out in a single-degree-of-freedom (SDOF) system framework since a multi-story building structure may be idealized as an equivalent SDOF system and investigation of the performance of this equivalent SDOF system can provide insight into the seismic response of the multi-story building. A peak-oriented hysteresis model which can consider the strength and stiffness degradation is used to describe the hysteretic behavior of RC structures. The parametric study involves two key parameters -the strength ratio and elastic stiffness ratio between the seismic retrofit system and the original RC frame. An ensemble of 172 earthquake ground motion records scaled to the design basis earthquake in California with a probability of exceedance of 10% in 50 years was constructed for the simulation-based parametric study. The effectiveness of the two seismic retrofit schemes considered in this study is evaluated in terms of peak displacement ratio,peak acceleration ratio,energy dissipation demand ratio and residual displacement ratio between the SDOF systems with and without retrofit. It is found from this parametric study that RC structures retrofitted with the self-centering retrofit scheme (SCRS) can achieve a seismic performance level comparable to the bilinear-hysteresis retrofit scheme (BHRS) in terms of peak displacement and energy dissipation demand ratio while having negligible residual displacement after earthquake.
基金supported by Youth Technological Phosphor Project of Shanghai City (No.04QMX1474).
文摘Firstly, in view of the respective defects of existing self-centering devices for vehicle suspension height, the design scheme of the proposed mechanical self-centering device for suspension height is described. Taking the rear suspension of a certain light bus as a research example, the structures and parameters of the novel device are designed and ascertained. Then, the road excitation models, the performance evaluation indexes and the half-vehicle model are built, the simulation outputs of time and frequency domain are obtained with the road excitations of random and pulse by using MATLAB/Simulink software. So the main characteristics of the self-centering suspension are presented preliminarily. Finally, a multi-objective parameter design optimization model for the self-centering device is built by weighted sum approach, and optimal solution is obtained by adopting complex approach. The relevant choosing-type parameters for self-centering device components are deduced by using discrete variable optimal method, and the optimal results are verified and analyzed. So the performance potentials of the self-centering device are exerted fully in condition of ensuring overall suspension performances.
基金National Key Research and Development Program of China under Grant No.2018YFC0705602。
文摘Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during the rocking process.An innovative RW with a curved interface is proposed to prevent interfacial corners from producing local damage,enhancing its earthquake resilient performance(ERP).The precast wall panel with a curved interface is assembled into an integral self-centering hybrid rocking wall(SCRW)by two post-tensioned unbonded prestressed tendons.Moreover,two ordinary energy dissipation steel rebars and two shear reinforcements are arranged to increase the energy dissipation capacity and lateral resistance.Two SCRW specimens and one monolithic reinforced concrete(RC)shear wall(SW)were tested under pseudo-static loading to compare the ERPs of the proposed SCRW and the SW,focusing on studying the effect of the curved interface on the SCRW.The key resilient performance of rocking effects,failure modes,and hysteretic properties of the SCRW were explored.The results show that nonlinear deformations of the SCRW are concentrated along the interface between the SCRW and the foundation,avoiding damage within the SCRW.The restoring force provided by the prestressed tendons can effectively realize self-centering capacity with small residual deformation,and the resilient performance of the SCRW is better than that of monolithic SW.In addition,the curved interface of the SCRW makes the rocking center change and move inward,partially relieving the stress concentration and crush of concrete.The rocking range of the rocking center is about 41.4%of the width of the SCRW.
基金National Natural Science Foundation of China Under Grant No. 51078075a grant from Southeast University (No. 3205000502)the financial support from the State Key Lab of Subtropical Building Science, South China University of Technology under Grant No. 2010KB05
文摘A new type of steel moment resisting frame with bottom flange friction devices （BFFDs） has been developed to provide self-centering capacity and energy dissipation, and to reduce permanent deformations under earthquakes. This paper presents a numerical simulation of self-centering beam-column connections with BFFDs, in which the gap opening/closing at the beam-column interfaces is simulated by using pairs of zero-length elements with compression-only material properties, and the energy dissipation due to friction is simulated by using truss elements with specified hysteretic behavior. In particular, the effect of the friction bolt bearing against the slotted plate in the BFFDs was modeled, so that the increase in lateral force and the loss of friction force due to the bolt bearing could be taken into account. Parallel elastic-perfectly plastic gap （ElasticPPGap） materials in the Open System for Earthquake Engineering Simulation （OpenSees） were used with predefined gaps to specify the sequence that each bolt went into the bearing and the corresponding increase in bending stiffness. The MinMax material in OpenSees is used to specify the minimum and maximum values of strains of the ElasticPPGap materials. To consider the loss of friction force due to bok bearing, a number of parallel hysteretic materials were used, and the failure of these materials in sequence simulated the gradual loss of friction force. Analysis results obtained by using the proposed numerical model are discussed and compared with the test results under cyclic loadings and the seismic loading, respectively.
基金supported by R01 NS093009 grant from NIH(to VVC).
文摘Development of the telencephalon relies upon several signaling centers-localized cellular populations that supply secreted factors to pattern the cortical neuroepithelium.One such signaling center is the cortical hem,which arises during embryonic development at the telencephalic dorsal midline,adjacent to the choroid plexus and hippocampal primordium(Figure 1A).While the cortical hem has also been described in reptiles and birds,most of our knowledge about the developmental roles of the cortical hem is derived from the analysis in mice.The cortical hem produces several types of secreted molecules,including wingless-related integration site(Wnt)and bone morphogenetic(Bmp)proteins.The cortical hem is particularly important for the development of the hippocampus,which is involved in learning and memory,and the neocortex,which is the most complex brain region that mediates multiple types of behavior and higher cognitive functions(Mangale et al.,2008;Dal-Valle-Anton and Borrell,2022).
基金supported by the National Natural Science Foundation of China(Grant No.92044303)。
文摘Air pollution in China covers a large area with complex sources and formation mechanisms,making it a unique place to conduct air pollution and atmospheric chemistry research.The National Natural Science Foundation of China’s Major Research Plan entitled“Fundamental Researches on the Formation and Response Mechanism of the Air Pollution Complex in China”(or the Plan)has funded 76 research projects to explore the causes of air pollution in China,and the key processes of air pollution in atmospheric physics and atmospheric chemistry.In order to summarize the abundant data from the Plan and exhibit the long-term impacts domestically and internationally,an integration project is responsible for collecting the various types of data generated by the 76 projects of the Plan.This project has classified and integrated these data,forming eight categories containing 258 datasets and 15 technical reports in total.The integration project has led to the successful establishment of the China Air Pollution Data Center(CAPDC)platform,providing storage,retrieval,and download services for the eight categories.This platform has distinct features including data visualization,related project information querying,and bilingual services in both English and Chinese,which allows for rapid searching and downloading of data and provides a solid foundation of data and support for future related research.Air pollution control in China,especially in the past decade,is undeniably a global exemplar,and this data center is the first in China to focus on research into the country’s air pollution complex.
