Currently,the development of excellent red phosphor materials has attracted much attention in daily lighting,backlit displays,optical thermometry sensors and plant growthfields.However,spectral peak position modulatio...Currently,the development of excellent red phosphor materials has attracted much attention in daily lighting,backlit displays,optical thermometry sensors and plant growthfields.However,spectral peak position modulation and bandwidth are still crucial challenges.Herein,we design Eu^(3+)→Mn^(4+)energy transfer in the Lu_(3)Al_(5)O_(12)(LuAG)garnet host.On the one hand,photoluminescence tuning from narrow orangish-red emission(593 nm)to narrow deep-red light(668 nm)is successfully obtained,and the energy transfer effciency reaches 47%.On the other hand,LuAG:Eu^(3+)exhibits anti-thermal-quenching properties;that is,the peak intensity reaches 166%at 200℃of the initial intensity at 25℃.By designing Eu^(3+)→Mn^(4+)energy transfer,Mn^(4+)thermal quenching performance is dramatically improved.The photo luminescence peak intensities at 668 nm for LuAG:0.01Mn^(4+)and LuAG:0.05Eu^(3+),0.01Mn^(4+)retain 3.26%and 26%at 200℃of the original intensity at 25℃.The corresponding energy transfer mechanism to improve thermal quenching is revealed.According to thefluorescence intensity ratio technique,the maximum values of Sa and Sr for LuAG:0.05Eu^(3+),0.01Mn^(4+)are 0.07 K−1 and 0.7%K^(−1)at 303 K.The temp erature sensitivity calculation indicates that LuAG:Eu^(3+),Mn^(4+)phosphors can act as promising candidates in optical thermometry sensors.This work provides an insight to achieve narrow red emission modulation and thermal quenching improvement.展开更多
Plate-pin heat sinks are widely used for the electronic cooling system,internal combustion IC engine,cooling of gas turbine blades and other different applications to enhance the thermal performance of heat sinks due ...Plate-pin heat sinks are widely used for the electronic cooling system,internal combustion IC engine,cooling of gas turbine blades and other different applications to enhance the thermal performance of heat sinks due to simplicity,low cost,and a reliable manufacturing process.However,compact heat sinks give higher pressure drop compared with other types of heat sinks.The purpose of this article is to summarise the main advantages and disadvantages of the compact heat sink with some recommendation studies for future works heat sink thermal airflow experiment and simulations.Furthermore,the research attempts to highlight the importance of balance the relationship between the hydraulic performance and the thermal performance of compact heat sinks。展开更多
his thesis mainly discusses Chinese negative transfer in English learning--Chinglish and does some error analysis about it. Furthermore, how we look at Chinglish? And some measureswe should take to correct Chinglish.
By a survey of a range of existing literatures, this article makes a rough summary for previous theoretical findings about the role of side payment in international environmental agreements. If countries are symmetric...By a survey of a range of existing literatures, this article makes a rough summary for previous theoretical findings about the role of side payment in international environmental agreements. If countries are symmetric, we can hardly exploit the transfer to enhance international cooperation. On the contrary, under asymmetric countries assumption, the side payment is often helpful to obtaining better global outcome in environmental issues. Even though no general theoretical conclusion can be claimed so far, many meaningful implications will be revealed with the going on of this article.展开更多
A wavelet based identification method for linear time-varying systems is presented,and the ridge and skeleton of the continuous wavelet transform of free response is used to extract time-varying parameters. The stiffn...A wavelet based identification method for linear time-varying systems is presented,and the ridge and skeleton of the continuous wavelet transform of free response is used to extract time-varying parameters. The stiffness and damping coefficients of single-degree-of—freedom systems,frequencies and damping ratios of multi-degree-of-freedom systems are estimated without any prior information of systems. The proposed method is applied to linear time-varying systems with both abrupt and smooth variation parameters. Gaussian white noise is added to the response to test the anti-noise performance of the algorithm. The simulation results show that the proposed method is capable of accurately tracking the variation of the systems.展开更多
This paper,based on the investigation of students'autonomous English learning competence,aims to identify the problems students have in learner's autonomy(LA) and to further explore the possible ways to develo...This paper,based on the investigation of students'autonomous English learning competence,aims to identify the problems students have in learner's autonomy(LA) and to further explore the possible ways to develop students'autonomous English learning competence in Chinese context.展开更多
Based on the fractional discrete cosine transform(DCT) via polynomial interpolation(PI-Fr DCT) and the dependent scrambling and diffusion(DSD), an image encryption algorithm is proposed. Under certain conditions, the ...Based on the fractional discrete cosine transform(DCT) via polynomial interpolation(PI-Fr DCT) and the dependent scrambling and diffusion(DSD), an image encryption algorithm is proposed. Under certain conditions, the introduction of PI-Fr DCT reduces computational complexity compared with fractional DCT(Fr DCT). By using a sigmoid function, the encrypted results are limited within a range from 0 to 255. The real-valued output of PI-Fr DCT is beneficial to the storage, display and transmission of the cipher-text. During the stage of confusion and diffusion, the values of all PI-Fr DCT coefficients change simultaneously as their locations are replaced. DSD enhances the scrambling and diffusion level of encrypted images and provides nonlinearity to the encryption system. Simulation results demonstrate that the proposed encryption algorithm is feasible, effective and secure.展开更多
BASF has successfully completed its acquisition of Ciba Holding AG,which closed onApril 10 with the payment ofthe offer price to Ciba shareholders.At the same time,thetendered shares wore transferred to BASF.The compa...BASF has successfully completed its acquisition of Ciba Holding AG,which closed onApril 10 with the payment ofthe offer price to Ciba shareholders.At the same time,thetendered shares wore transferred to BASF.The company now holds 95.8% of Ciba.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.52072349,51672259 and 41807201)the Fundamental Research Funds for National Universities,China University of Geosciences(Wuhan)(No.1910491T02)the National College Students’Innovative Training Program(No.201910491003,201910491082,202010491002,202010491020 and 202010491053).
文摘Currently,the development of excellent red phosphor materials has attracted much attention in daily lighting,backlit displays,optical thermometry sensors and plant growthfields.However,spectral peak position modulation and bandwidth are still crucial challenges.Herein,we design Eu^(3+)→Mn^(4+)energy transfer in the Lu_(3)Al_(5)O_(12)(LuAG)garnet host.On the one hand,photoluminescence tuning from narrow orangish-red emission(593 nm)to narrow deep-red light(668 nm)is successfully obtained,and the energy transfer effciency reaches 47%.On the other hand,LuAG:Eu^(3+)exhibits anti-thermal-quenching properties;that is,the peak intensity reaches 166%at 200℃of the initial intensity at 25℃.By designing Eu^(3+)→Mn^(4+)energy transfer,Mn^(4+)thermal quenching performance is dramatically improved.The photo luminescence peak intensities at 668 nm for LuAG:0.01Mn^(4+)and LuAG:0.05Eu^(3+),0.01Mn^(4+)retain 3.26%and 26%at 200℃of the original intensity at 25℃.The corresponding energy transfer mechanism to improve thermal quenching is revealed.According to thefluorescence intensity ratio technique,the maximum values of Sa and Sr for LuAG:0.05Eu^(3+),0.01Mn^(4+)are 0.07 K−1 and 0.7%K^(−1)at 303 K.The temp erature sensitivity calculation indicates that LuAG:Eu^(3+),Mn^(4+)phosphors can act as promising candidates in optical thermometry sensors.This work provides an insight to achieve narrow red emission modulation and thermal quenching improvement.
文摘Plate-pin heat sinks are widely used for the electronic cooling system,internal combustion IC engine,cooling of gas turbine blades and other different applications to enhance the thermal performance of heat sinks due to simplicity,low cost,and a reliable manufacturing process.However,compact heat sinks give higher pressure drop compared with other types of heat sinks.The purpose of this article is to summarise the main advantages and disadvantages of the compact heat sink with some recommendation studies for future works heat sink thermal airflow experiment and simulations.Furthermore,the research attempts to highlight the importance of balance the relationship between the hydraulic performance and the thermal performance of compact heat sinks。
文摘his thesis mainly discusses Chinese negative transfer in English learning--Chinglish and does some error analysis about it. Furthermore, how we look at Chinglish? And some measureswe should take to correct Chinglish.
文摘By a survey of a range of existing literatures, this article makes a rough summary for previous theoretical findings about the role of side payment in international environmental agreements. If countries are symmetric, we can hardly exploit the transfer to enhance international cooperation. On the contrary, under asymmetric countries assumption, the side payment is often helpful to obtaining better global outcome in environmental issues. Even though no general theoretical conclusion can be claimed so far, many meaningful implications will be revealed with the going on of this article.
文摘A wavelet based identification method for linear time-varying systems is presented,and the ridge and skeleton of the continuous wavelet transform of free response is used to extract time-varying parameters. The stiffness and damping coefficients of single-degree-of—freedom systems,frequencies and damping ratios of multi-degree-of-freedom systems are estimated without any prior information of systems. The proposed method is applied to linear time-varying systems with both abrupt and smooth variation parameters. Gaussian white noise is added to the response to test the anti-noise performance of the algorithm. The simulation results show that the proposed method is capable of accurately tracking the variation of the systems.
文摘This paper,based on the investigation of students'autonomous English learning competence,aims to identify the problems students have in learner's autonomy(LA) and to further explore the possible ways to develop students'autonomous English learning competence in Chinese context.
基金supported by the National Natural Science Foundation of China(61262084,61462061)the Natural Science Foundation of Jiangxi Province(20122BAB201029)
文摘Based on the fractional discrete cosine transform(DCT) via polynomial interpolation(PI-Fr DCT) and the dependent scrambling and diffusion(DSD), an image encryption algorithm is proposed. Under certain conditions, the introduction of PI-Fr DCT reduces computational complexity compared with fractional DCT(Fr DCT). By using a sigmoid function, the encrypted results are limited within a range from 0 to 255. The real-valued output of PI-Fr DCT is beneficial to the storage, display and transmission of the cipher-text. During the stage of confusion and diffusion, the values of all PI-Fr DCT coefficients change simultaneously as their locations are replaced. DSD enhances the scrambling and diffusion level of encrypted images and provides nonlinearity to the encryption system. Simulation results demonstrate that the proposed encryption algorithm is feasible, effective and secure.
文摘BASF has successfully completed its acquisition of Ciba Holding AG,which closed onApril 10 with the payment ofthe offer price to Ciba shareholders.At the same time,thetendered shares wore transferred to BASF.The company now holds 95.8% of Ciba.
