The production of colored flames is the primary purpose of military signaling, projectile tracing, and illuminating devices. Certain elements and compounds when heated to high temperature have the unique property of e...The production of colored flames is the primary purpose of military signaling, projectile tracing, and illuminating devices. Certain elements and compounds when heated to high temperature have the unique property of emitting lines or narrow bands in the visible region(380-780 nm). This study, reports on the development of novel yellow colored flame compositions with enhanced spectral performance in terms of luminous intensity, and color quality to standard Russian yellow tracer. The light intensity and the imprint spectra of developed yellow flares were measured using digital luxmeter and UV e Vis. spectrometer respectively. The main giving of this study is that the light intensity, and color quality of Russian yellow tracer were improved by 287%, and 170% respectively. This was accomplished by means of optimizing the ratio of novel binder to color source using aluminum metal fuel. Aluminumbased formulations were found to maximize the formation of yellow reactive emitting specimens, and to eliminate any interfering incandescent emission resulted from Mg O. Quantification of yellow color emitting specimens in the combustion gaseous products was achieved using chemical equilibrium thermodynamic code named ICT(Institute of Chemical Technology in Germany, Virgin 2008); in an attempt to judge the light quality. This improvement in yellow flare performance established the rule that the emission intensity increases as the reaction temperature increases. In the meantime upper limit of temperature was avoided to maximize the color quality.展开更多
Cognitive radio(CR) is a promising solution to improve the spectrum utilization.The cognitive radio networks includes the primary user(PU) system with authorized spectrum and the secondly user(SU) system without autho...Cognitive radio(CR) is a promising solution to improve the spectrum utilization.The cognitive radio networks includes the primary user(PU) system with authorized spectrum and the secondly user(SU) system without authorized spectrum. When the SUs want to use the spectrum, they have to find the idle channels that are not occupied by the PUs. So the QoS of the SUs will be affected not only by the characteristic of their own business, but also by the behavior of the PUs.Currently, in order to ensure the quality of the SU services, the M-LDWF algorithm is widely used in scheduling. However, the M-LWDF algorithm didn't fully consider the difference among the SUs. For those SUs who are in the process of communication but have to change channel due to the return of the PU, they should have higher scheduling priority. In this paper, we put forward an improved algorithm based on M-LWDF. In order to guarantee the QoS of the SUs those were in the processing of communication, we gave the higher scheduling priority. Simulation results show that the improved algorithm can effectively decrease the dropping rate and improve the QoS of the SUs and the performance of the whole system.展开更多
This paper proposes a negotiation-based TDMA scheme for ad hoc networks, which was modeled as an asynchronous myopic repeated game. Compared to the traditional centralized TDMA schemes, our scheme operates in a decent...This paper proposes a negotiation-based TDMA scheme for ad hoc networks, which was modeled as an asynchronous myopic repeated game. Compared to the traditional centralized TDMA schemes, our scheme operates in a decentralized manner and is scalable to topology changes. Simulation results show that, with respect to the coloring quality, the performance of our scheme is close to that of the classical centralized algorithms with much lower complexity.展开更多
基金funding the research project entitled“Enhanced Visible Tracers for Illumination and Tracking”
文摘The production of colored flames is the primary purpose of military signaling, projectile tracing, and illuminating devices. Certain elements and compounds when heated to high temperature have the unique property of emitting lines or narrow bands in the visible region(380-780 nm). This study, reports on the development of novel yellow colored flame compositions with enhanced spectral performance in terms of luminous intensity, and color quality to standard Russian yellow tracer. The light intensity and the imprint spectra of developed yellow flares were measured using digital luxmeter and UV e Vis. spectrometer respectively. The main giving of this study is that the light intensity, and color quality of Russian yellow tracer were improved by 287%, and 170% respectively. This was accomplished by means of optimizing the ratio of novel binder to color source using aluminum metal fuel. Aluminumbased formulations were found to maximize the formation of yellow reactive emitting specimens, and to eliminate any interfering incandescent emission resulted from Mg O. Quantification of yellow color emitting specimens in the combustion gaseous products was achieved using chemical equilibrium thermodynamic code named ICT(Institute of Chemical Technology in Germany, Virgin 2008); in an attempt to judge the light quality. This improvement in yellow flare performance established the rule that the emission intensity increases as the reaction temperature increases. In the meantime upper limit of temperature was avoided to maximize the color quality.
基金supported by Beijing Key Laboratory of Work Safety Intelligent Monitoring (Beijing University of Posts and Telecommunications)
文摘Cognitive radio(CR) is a promising solution to improve the spectrum utilization.The cognitive radio networks includes the primary user(PU) system with authorized spectrum and the secondly user(SU) system without authorized spectrum. When the SUs want to use the spectrum, they have to find the idle channels that are not occupied by the PUs. So the QoS of the SUs will be affected not only by the characteristic of their own business, but also by the behavior of the PUs.Currently, in order to ensure the quality of the SU services, the M-LDWF algorithm is widely used in scheduling. However, the M-LWDF algorithm didn't fully consider the difference among the SUs. For those SUs who are in the process of communication but have to change channel due to the return of the PU, they should have higher scheduling priority. In this paper, we put forward an improved algorithm based on M-LWDF. In order to guarantee the QoS of the SUs those were in the processing of communication, we gave the higher scheduling priority. Simulation results show that the improved algorithm can effectively decrease the dropping rate and improve the QoS of the SUs and the performance of the whole system.
基金supported in part by National Science Fund for Distinguished Young Scholars under Grant No.60725105National Key Basic Research Program of China ( 973 Program ) under Grant No.2009CB320404+2 种基金Program for Changjiang Scholars and Innovative Research Team in University under Grant No.IRT0852National Natural Science Foundation of China under Grants No.60972047, 61072068111 Project under Grant No.B08038
文摘This paper proposes a negotiation-based TDMA scheme for ad hoc networks, which was modeled as an asynchronous myopic repeated game. Compared to the traditional centralized TDMA schemes, our scheme operates in a decentralized manner and is scalable to topology changes. Simulation results show that, with respect to the coloring quality, the performance of our scheme is close to that of the classical centralized algorithms with much lower complexity.
