Nitrogen doped fluorinated amorphous carbon thin films(a-C:N:F)were prepared by radio frequency plasma enhanced chemical vapor deposition(rf-PECVD)under different deposited condition usingCH_4,CF_4,and N_2 as source g...Nitrogen doped fluorinated amorphous carbon thin films(a-C:N:F)were prepared by radio frequency plasma enhanced chemical vapor deposition(rf-PECVD)under different deposited condition usingCH_4,CF_4,and N_2 as source gases.The thin films were annealed at different temperature.The influence of doped nitrogen on the chemical structure, tribological and thermal properties of thin films were investigated by Atomic force microscopy(AFM),Fourier transform infrared absorption spectrometry(FTIR),X-ray photoelectron spectrum spectra(XPS),and thermogravimetry(TG).The results indicated that the thin films presence a compact and smooth morphology surface after the nitrogen doped.After incorporation of nitrogen,the H atoms are replaced partially by the N atoms in the thin films.The degree of cross-linking of the carbon network in the thin films is enhanced.The chemical bonds of C=N,C≡N,and C—N_x(x=1,2,3) have formed in the films.The relative content of sp^2 graphite phase increases.The thermal stability temperature of the films deposited at r=0.5(r=N_2/[CF_4+CH_4+N_2])is 420℃.The tribological properties improve greatly,and the friction coefficient of the a-C:N:F thin films ranges approximately from 0.20 to 0.36.展开更多
The linear consecutive-k-out-of-n:failure(good)(Lin/Con/k/n:F(G))system consists of n interchangeable components that have different reliabilities.These components are arranged in a line path and different component a...The linear consecutive-k-out-of-n:failure(good)(Lin/Con/k/n:F(G))system consists of n interchangeable components that have different reliabilities.These components are arranged in a line path and different component assignments change the system reliability.The optimization of Lin/Con/k/n:F(G)system is to find an optimal component assignment to maximize the system reliability.As the number of components increases,the computation time for this problem increases considerably.In this paper,we propose a Birnbaum importance-based ant colony optimization(BIACO)algorithm to obtain quasi optimal assignments for such problems.We compare its performance using the Birnbaum importance based two-stage approach(BITA)and Birnbaum importancebased genetic local search(BIGLS)algorithm from previous researches.The experimental results show that the BIACO algorithm has a good performance in the optimization of Lin/Con/k/n:F(G)system.展开更多
A consecutive k out of n: F System, with n linearly arranged i. i. d. components, is examined. This paper gives an exact formula for computing the system's reliability directly. Complexity of this algorithm is...A consecutive k out of n: F System, with n linearly arranged i. i. d. components, is examined. This paper gives an exact formula for computing the system's reliability directly. Complexity of this algorithm is an O(n k). Further more, the system's reliability can be computed more quickly and more effectively from this formula than those previously given.展开更多
基金Item Sponsored by National Natural Science Foundation of China[No.11064003]
文摘Nitrogen doped fluorinated amorphous carbon thin films(a-C:N:F)were prepared by radio frequency plasma enhanced chemical vapor deposition(rf-PECVD)under different deposited condition usingCH_4,CF_4,and N_2 as source gases.The thin films were annealed at different temperature.The influence of doped nitrogen on the chemical structure, tribological and thermal properties of thin films were investigated by Atomic force microscopy(AFM),Fourier transform infrared absorption spectrometry(FTIR),X-ray photoelectron spectrum spectra(XPS),and thermogravimetry(TG).The results indicated that the thin films presence a compact and smooth morphology surface after the nitrogen doped.After incorporation of nitrogen,the H atoms are replaced partially by the N atoms in the thin films.The degree of cross-linking of the carbon network in the thin films is enhanced.The chemical bonds of C=N,C≡N,and C—N_x(x=1,2,3) have formed in the films.The relative content of sp^2 graphite phase increases.The thermal stability temperature of the films deposited at r=0.5(r=N_2/[CF_4+CH_4+N_2])is 420℃.The tribological properties improve greatly,and the friction coefficient of the a-C:N:F thin films ranges approximately from 0.20 to 0.36.
基金the National Natural Science Foundation of China(Nos.71871181 and 71471147)the Overseas Expertise Introduction Project for Discipline Innovation(No.B13044)the Top International University Visiting Program for Outstanding Young Scholars of Northwestern Polytechnical University(No.201806295008)。
文摘The linear consecutive-k-out-of-n:failure(good)(Lin/Con/k/n:F(G))system consists of n interchangeable components that have different reliabilities.These components are arranged in a line path and different component assignments change the system reliability.The optimization of Lin/Con/k/n:F(G)system is to find an optimal component assignment to maximize the system reliability.As the number of components increases,the computation time for this problem increases considerably.In this paper,we propose a Birnbaum importance-based ant colony optimization(BIACO)algorithm to obtain quasi optimal assignments for such problems.We compare its performance using the Birnbaum importance based two-stage approach(BITA)and Birnbaum importancebased genetic local search(BIGLS)algorithm from previous researches.The experimental results show that the BIACO algorithm has a good performance in the optimization of Lin/Con/k/n:F(G)system.
文摘A consecutive k out of n: F System, with n linearly arranged i. i. d. components, is examined. This paper gives an exact formula for computing the system's reliability directly. Complexity of this algorithm is an O(n k). Further more, the system's reliability can be computed more quickly and more effectively from this formula than those previously given.
