The 3D hollow hierarchi-cal architectures tend to be designed for inhibiting stack of MXene flakes to obtain satisfactory lightweight,high-e cient and broadband absorbers.Herein,the hollow NiCo compound@MXene networks...The 3D hollow hierarchi-cal architectures tend to be designed for inhibiting stack of MXene flakes to obtain satisfactory lightweight,high-e cient and broadband absorbers.Herein,the hollow NiCo compound@MXene networks were prepared by etching the ZIF 67 template and subsequently anchoring the Ti_(3)C_(2)Tx nanosheets through electrostatic self-assembly.The electromagnetic parameters and microwave absorption property can be distinctly or slightly regulated by adjusting the filler loading and decoration of Ti_(3)C_(2)Tx nanoflakes.Based on the synergistic e ectsof multi-components and special well-constructed structure,NiCo layered double hydroxides@Ti_(3)C_(2)Tx(LDHT-9)absorber remarkably achieves unexpected e ective absorption bandwidth(EAB)of 6.72 GHz with a thickness of 2.10 mm,covering the entire Ku-band.After calcination,transition metal oxide@Ti_(3)C_(2)Tx(TMOT-21)absorber near the percolation threshold possesses minimum reflection loss(RLmin)value of-67.22 dB at 1.70 mm within a filler loading of only 5 wt%.This work enlightens a simple strategy for constructing MXene-based composites to achieve high-e cient microwave absorbents with lightweight and tunable EAB.展开更多
The software architecture is a design of application system,performance evaluation of software architecture during the early stage of their development is really attractive. This paper proposes a new method for softwa...The software architecture is a design of application system,performance evaluation of software architecture during the early stage of their development is really attractive. This paper proposes a new method for software architecture performance modeling. To achieve this ,it adds new calculus into stochastic process algebra(SPA in short),the developed SPA called extended stochastic process algebra (ESPA in short). By ESPA,performance evaluation and software architecture modeling can combine perfectly. It defines a few performance terms for software architecture using reward structure derived from ESPA. To explain the performance terms it also designs an experiment.展开更多
Graph is a well known data structure to represent the associated relationships in a variety of applications,e.g.,data science and machine learning.Despite a wealth of existing efforts on developing graph processing sy...Graph is a well known data structure to represent the associated relationships in a variety of applications,e.g.,data science and machine learning.Despite a wealth of existing efforts on developing graph processing systems for improving the performance and/or energy efficiency on traditional architectures,dedicated hardware solutions,also referred to as graph processing accelerators,are essential and emerging to provide the benefits significantly beyond what those pure software solutions can offer.In this paper,we conduct a systematical survey regarding the design and implementation of graph processing accelerators.Specifically,we review the relevant techniques in three core components toward a graph processing accelerator:preprocessing,parallel graph computation,and runtime scheduling.We also examine the benchmarks and results in existing studies for evaluating a graph processing accelerator.Interestingly,we find that there is not an absolute winner for all three aspects in graph acceleration due to the diverse characteristics of graph processing and the complexity of hardware configurations.We finally present and discuss several challenges in details,and further explore the opportunities for the future research.展开更多
景观绩效研究为支撑、评价和指导景观实践提供重要科学依据。随着相关研究文献数量的大幅增长,传统文献梳理方式难以客观把握当前研究内容的宽度与深度。CiteSpace作为当前文献信息可视化分析的主要工具,为挖掘研究知识的网络结构和前...景观绩效研究为支撑、评价和指导景观实践提供重要科学依据。随着相关研究文献数量的大幅增长,传统文献梳理方式难以客观把握当前研究内容的宽度与深度。CiteSpace作为当前文献信息可视化分析的主要工具,为挖掘研究知识的网络结构和前沿动向提供技术支持。以Web of Science数据库所收录2000—2017年的景观绩效文献为研究对象,通过计量分析和人工检阅结合的述评方式,客观定量地呈现当前景观绩效研究的文献概况和发展脉络,进而系统揭示景观绩效研究的七大重点领域和两大前沿方向,为拓展中国当前研究内容和明确未来发展方向提供参考,以期推动中国景观绩效研究的进一步发展。展开更多
基金supported by the National Natural Science Foundation of China(No.52073010)Beijing Natural Science Foundation(2214069)。
文摘The 3D hollow hierarchi-cal architectures tend to be designed for inhibiting stack of MXene flakes to obtain satisfactory lightweight,high-e cient and broadband absorbers.Herein,the hollow NiCo compound@MXene networks were prepared by etching the ZIF 67 template and subsequently anchoring the Ti_(3)C_(2)Tx nanosheets through electrostatic self-assembly.The electromagnetic parameters and microwave absorption property can be distinctly or slightly regulated by adjusting the filler loading and decoration of Ti_(3)C_(2)Tx nanoflakes.Based on the synergistic e ectsof multi-components and special well-constructed structure,NiCo layered double hydroxides@Ti_(3)C_(2)Tx(LDHT-9)absorber remarkably achieves unexpected e ective absorption bandwidth(EAB)of 6.72 GHz with a thickness of 2.10 mm,covering the entire Ku-band.After calcination,transition metal oxide@Ti_(3)C_(2)Tx(TMOT-21)absorber near the percolation threshold possesses minimum reflection loss(RLmin)value of-67.22 dB at 1.70 mm within a filler loading of only 5 wt%.This work enlightens a simple strategy for constructing MXene-based composites to achieve high-e cient microwave absorbents with lightweight and tunable EAB.
文摘The software architecture is a design of application system,performance evaluation of software architecture during the early stage of their development is really attractive. This paper proposes a new method for software architecture performance modeling. To achieve this ,it adds new calculus into stochastic process algebra(SPA in short),the developed SPA called extended stochastic process algebra (ESPA in short). By ESPA,performance evaluation and software architecture modeling can combine perfectly. It defines a few performance terms for software architecture using reward structure derived from ESPA. To explain the performance terms it also designs an experiment.
基金the National Key Research and Development Program of China under Grant No.2018YFB1003502the National Natural Science Foundation of China under Grant Nos.61825202,61832006,61628204 and 61702201.
文摘Graph is a well known data structure to represent the associated relationships in a variety of applications,e.g.,data science and machine learning.Despite a wealth of existing efforts on developing graph processing systems for improving the performance and/or energy efficiency on traditional architectures,dedicated hardware solutions,also referred to as graph processing accelerators,are essential and emerging to provide the benefits significantly beyond what those pure software solutions can offer.In this paper,we conduct a systematical survey regarding the design and implementation of graph processing accelerators.Specifically,we review the relevant techniques in three core components toward a graph processing accelerator:preprocessing,parallel graph computation,and runtime scheduling.We also examine the benchmarks and results in existing studies for evaluating a graph processing accelerator.Interestingly,we find that there is not an absolute winner for all three aspects in graph acceleration due to the diverse characteristics of graph processing and the complexity of hardware configurations.We finally present and discuss several challenges in details,and further explore the opportunities for the future research.
文摘景观绩效研究为支撑、评价和指导景观实践提供重要科学依据。随着相关研究文献数量的大幅增长,传统文献梳理方式难以客观把握当前研究内容的宽度与深度。CiteSpace作为当前文献信息可视化分析的主要工具,为挖掘研究知识的网络结构和前沿动向提供技术支持。以Web of Science数据库所收录2000—2017年的景观绩效文献为研究对象,通过计量分析和人工检阅结合的述评方式,客观定量地呈现当前景观绩效研究的文献概况和发展脉络,进而系统揭示景观绩效研究的七大重点领域和两大前沿方向,为拓展中国当前研究内容和明确未来发展方向提供参考,以期推动中国景观绩效研究的进一步发展。
