The pavement layered structures are composed of surface layer,road base and multi-layered soil foundation.They can be undermined over time by repeated vehicle loads.In this study,a hybrid numerical method which can ev...The pavement layered structures are composed of surface layer,road base and multi-layered soil foundation.They can be undermined over time by repeated vehicle loads.In this study,a hybrid numerical method which can evaluate the displacement responses of pavement structures under dynamic falling weight deflectometer(FWD)loads.The proposed method consists of two parts:(a)the dynamic stiffness matrices of the points at the surface in the frequency domain which is based on the domain-transformation and dual vector form equation,and(b)interpolates the dynamic stiffness matrices by a continues rational function of frequency.The mixed variables formulation(MVF)can treat multiple degree of freedom systems with considering the coupling term between degree of freedoms.The accuracy of the developed method has been demonstrated by comparison between the proposed method and published results from the other method.Then the proposed method can be applied as a forward calculation technique to emulate the falling weight deflectometer test for multi-layered pavement structures.展开更多
The development of wireless communication technology has become increasingly important in the communications industry.How to allocate limited channel resources reasonably and reliably to each competing user is a probl...The development of wireless communication technology has become increasingly important in the communications industry.How to allocate limited channel resources reasonably and reliably to each competing user is a problem that the access protocol of the MAC(Multiple Access Control)layer needs to solve.As an important way of random access,NP-CSMA(Non Persistent Carrier Sense Multiple Access)has a higher network throughput rate when the arrival rate is higher.This paper analyzes and improves the implemented NP-CSMA model,and obtains a three-slot NP-CSMA model.The mathematical tool MATLAB is used to analyze the network throughput,delay and energy efficiency of the model,and compare several random multiple access protocols adheres to the network throughput,they are NP-CSMA,Three-slot NP-CSMA,1-persistent CSMA,P-persistent CSMA,and concludes that the three-slot NP-CSMA is significantly letter than several other multiple access protocols.Finally,using Quartus to design the three-slot NP-CSMA circuit,the statistical value of the circuit system is compared with the theoretical value of the model,and the error is less than 0.01,which proves that the system is reasonable in design and can be applied to wireless communication networks.展开更多
Globally,millions of people die of microbial infection-related diseases every year.The more terrible situation is that due to the overuse of antibiotics,especially in developing countries,people are struggling to figh...Globally,millions of people die of microbial infection-related diseases every year.The more terrible situation is that due to the overuse of antibiotics,especially in developing countries,people are struggling to fight with the bacteria variation.The emergence of super-bacteria will be an intractable environmental and health hazard in the future unless novel bactericidal weapons are mounted.Consequently,it is critical to develop viable antibacterial approaches to sustain the prosperous development of human society.Recent researches indicate that transition metal sulfides(TMSs)represent prominent bactericidal application potential owing to the meritorious antibacterial performance,acceptable biocompatibility,high solar energy utilization efficiency,and excellent photo-to-thermal conversion characteristics,and thus,a comprehensive review on the recent advances in this area would be beneficial for the future development.In this review article,we start with the antibacterial mechanisms of TMSs to provide a preliminary understanding.Thereafter,the state-of-the-art research progresses on the strategies for TMSs materials engineering so as to promote their antibacterial properties are systematically surveyed and summarized,followed by a summary of the practical application scenarios of TMSs-based antibacterial platforms.Finally,based on the thorough survey and analysis,we emphasize the challenges and future development trends in this area.展开更多
SnO 2 nanospheres with diameters of 30∼50 nm and Pt x Cu 1-x bimetallic nanoparticles with sizes of approxi-mately 10 nm were synthesized via hydrothermal and solvothermal methods,respectively.The Pt x Cu 1-x bimetal...SnO 2 nanospheres with diameters of 30∼50 nm and Pt x Cu 1-x bimetallic nanoparticles with sizes of approxi-mately 10 nm were synthesized via hydrothermal and solvothermal methods,respectively.The Pt x Cu 1-x bimetal-lic nanoparticles were impregnated on the surface of the SnO 2 spheres to form Pt x Cu 1-x-SnO 2 nanocomposites.By varying the atomic ratios between platinum(Pt)and copper(Cu),we found that Pt 0.75 Cu 0.25-SnO 2,with a large specific surface area of 89.21 m 2/g,enabled the selective and accurate detection of low-concentration formalde-hyde compared to other metal-deposited samples and pure SnO 2.The response value of Pt 0.75 Cu 0.25-SnO 2 to 500×10−9 formaldehyde was approximately 20 at an operating temperature of 160◦C with an extremely high-speed response(15 s).The porous structures with large specific surface areas,as well as the improved catalytic effects of Pt 0.75 Cu 0.25,comprehensively contributed to the enhanced sensing performance towards formaldehyde.展开更多
基金The authors are grateful for the financial support of the National Key Research and Development Program of China(No.2016YFC0802400)the National Natural Science Foundation of China under Grant No.(51508203,51678536,41404096)+2 种基金the Outstanding Young Talent Research Fund of Zhengzhou University(1621323001)Program for Innovative Research Team(in Science and Technology)in University of Henan Province(18IRTSTHN007)the Program for Science and Technology Innovation Talents in Universities of Henan Province(Grant No.19HASTIT043),and the authors extend their sincere gratitude.
文摘The pavement layered structures are composed of surface layer,road base and multi-layered soil foundation.They can be undermined over time by repeated vehicle loads.In this study,a hybrid numerical method which can evaluate the displacement responses of pavement structures under dynamic falling weight deflectometer(FWD)loads.The proposed method consists of two parts:(a)the dynamic stiffness matrices of the points at the surface in the frequency domain which is based on the domain-transformation and dual vector form equation,and(b)interpolates the dynamic stiffness matrices by a continues rational function of frequency.The mixed variables formulation(MVF)can treat multiple degree of freedom systems with considering the coupling term between degree of freedoms.The accuracy of the developed method has been demonstrated by comparison between the proposed method and published results from the other method.Then the proposed method can be applied as a forward calculation technique to emulate the falling weight deflectometer test for multi-layered pavement structures.
基金This work was supported by the National Natural Science Foundation of China(61461053,61461054,61072079,61463049)The Financial Support of Yunnan University(No.XT412004).
文摘The development of wireless communication technology has become increasingly important in the communications industry.How to allocate limited channel resources reasonably and reliably to each competing user is a problem that the access protocol of the MAC(Multiple Access Control)layer needs to solve.As an important way of random access,NP-CSMA(Non Persistent Carrier Sense Multiple Access)has a higher network throughput rate when the arrival rate is higher.This paper analyzes and improves the implemented NP-CSMA model,and obtains a three-slot NP-CSMA model.The mathematical tool MATLAB is used to analyze the network throughput,delay and energy efficiency of the model,and compare several random multiple access protocols adheres to the network throughput,they are NP-CSMA,Three-slot NP-CSMA,1-persistent CSMA,P-persistent CSMA,and concludes that the three-slot NP-CSMA is significantly letter than several other multiple access protocols.Finally,using Quartus to design the three-slot NP-CSMA circuit,the statistical value of the circuit system is compared with the theoretical value of the model,and the error is less than 0.01,which proves that the system is reasonable in design and can be applied to wireless communication networks.
基金supported by the National Natural Science Foundation of China(Nos.21902085 and 51572157)the Natural Science Foundation of Shandong Province(Nos.ZR2019QF012 and ZR2019BEM024)+7 种基金Shenzhen Fundamental Research Program(Nos.JCYJ20190807093205660 and JCYJ20190807092803583)the Natural Science Foundation of Jiangsu Province(No.BK20190205)the Guangdong Basic and Applied Basic Research Foundation(No.2019A1515110846)the Fundamental Research Funds for the Central Universities(Nos.2018JC046 and 2018JC047)Medical and Health Science and Technology Development Project of Shandong Province(No.2018WSA01018)Science Development Program Project of Jinan(No.201805048)the Deans Research Assistance Foundation of Ji Nan Stomatology Hospital(2018-02)the Qilu Young Scholar Program of Shandong University(Nos.31370088963043 and 31370088963056).
文摘Globally,millions of people die of microbial infection-related diseases every year.The more terrible situation is that due to the overuse of antibiotics,especially in developing countries,people are struggling to fight with the bacteria variation.The emergence of super-bacteria will be an intractable environmental and health hazard in the future unless novel bactericidal weapons are mounted.Consequently,it is critical to develop viable antibacterial approaches to sustain the prosperous development of human society.Recent researches indicate that transition metal sulfides(TMSs)represent prominent bactericidal application potential owing to the meritorious antibacterial performance,acceptable biocompatibility,high solar energy utilization efficiency,and excellent photo-to-thermal conversion characteristics,and thus,a comprehensive review on the recent advances in this area would be beneficial for the future development.In this review article,we start with the antibacterial mechanisms of TMSs to provide a preliminary understanding.Thereafter,the state-of-the-art research progresses on the strategies for TMSs materials engineering so as to promote their antibacterial properties are systematically surveyed and summarized,followed by a summary of the practical application scenarios of TMSs-based antibacterial platforms.Finally,based on the thorough survey and analysis,we emphasize the challenges and future development trends in this area.
基金This study was supported by the Natural Science Foundation of Shan-dong Province(No.ZR2019QF012)the Natural Science and Develop-ment Foundation of Shenzhen(JCYJ20190807093205660)the Na-tional Natural Science Foundation of China(No.21902085).
文摘SnO 2 nanospheres with diameters of 30∼50 nm and Pt x Cu 1-x bimetallic nanoparticles with sizes of approxi-mately 10 nm were synthesized via hydrothermal and solvothermal methods,respectively.The Pt x Cu 1-x bimetal-lic nanoparticles were impregnated on the surface of the SnO 2 spheres to form Pt x Cu 1-x-SnO 2 nanocomposites.By varying the atomic ratios between platinum(Pt)and copper(Cu),we found that Pt 0.75 Cu 0.25-SnO 2,with a large specific surface area of 89.21 m 2/g,enabled the selective and accurate detection of low-concentration formalde-hyde compared to other metal-deposited samples and pure SnO 2.The response value of Pt 0.75 Cu 0.25-SnO 2 to 500×10−9 formaldehyde was approximately 20 at an operating temperature of 160◦C with an extremely high-speed response(15 s).The porous structures with large specific surface areas,as well as the improved catalytic effects of Pt 0.75 Cu 0.25,comprehensively contributed to the enhanced sensing performance towards formaldehyde.
