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101.
A resonator with a right-angle conical reflector has been proposed to produce high-power CO2 laser beams. To analyze eigenfields of the right-angle conical reflector resonator, this paper adopts and demonstrates the transfer matrix method. In this paper, the mode-fields and corresponding losses are described as eigenvectors and eigenvalues of a transfer matrix according to the self-reproducing principle of laser field. By solving the transfer matrix for eigenvectors and eigenvalues, we obtain field distributions and losses of the dominant eigenmodes. The calculation results reveal that the right-angle conical reflector resonator could be used for a high-power CO2 laser to achieve low-order modes. However, the beam quality is reduced due to the residual blind-hole, which is in accord with the experimental result. 相似文献
102.
103.
Haïkel Skhiri 《Journal of Mathematical Analysis and Applications》2009,358(2):320-326
Let B(H) be the algebra of all bounded linear operators on a complex infinite-dimensional Hilbert space H. For every T∈B(H), let m(T) and q(T) denote the minimum modulus and surjectivity modulus of T respectively. Let ?:B(H)→B(H) be a surjective linear map. In this paper, we prove that the following assertions are equivalent:
- (i)
- m(T)=m(?(T)) for all T∈B(H),
- (ii)
- q(T)=q(?(T)) for all T∈B(H),
- (iii)
- there exist two unitary operators U,V∈B(H) such that ?(T)=UTV for all T∈B(H).
104.
105.
Abdullah M. Abdul-Jabbar Chenar Abdul Kareem Ahmed Yang Lee Young Joo Seo 《代数通讯》2017,45(11):4881-4895
The reversible property is an important role in noncommutative ring theory. Recently, the study of the reversible ring property on nilpotent elements is established by Abdul-Jabbar et al., introducing the concept of commutativity of nilpotent elements at zero (simply, a CNZ ring) as a generalization of reversible rings. We here study this property skewed by a ring endomorphism α, and such ring is called a right α-skew CNZ ring which is an extension of CNZ rings as well as a generalization of right α-skew reversible rings, and then investigate the structure of right α-skew CNZ rings and their related properties. Consequently, several known results are obtained as corollaries of our results. 相似文献
106.
Cédric Heuchenne Ingrid Van Keilegom 《Annals of the Institute of Statistical Mathematics》2007,59(2):273-297
Consider the polynomial regression model
, where σ2(X)=Var(Y|X) is unknown, and ε is independent of X and has zero mean. Suppose that Y is subject to random right censoring. A new estimation procedure for the parameters β0,...,β
p
is proposed, which extends the classical least squares procedure to censored data. The proposed method is inspired by the
method of Buckley and James (1979, Biometrika, 66, 429–436), but is, unlike the latter method, a noniterative procedure due to nonparametric preliminary estimation of the
conditional regression function. The asymptotic normality of the estimators is established. Simulations are carried out for
both methods and they show that the proposed estimators have usually smaller variance and smaller mean squared error than
the Buckley–James estimators. The two estimation procedures are also applied to a medical and an astronomical data set. 相似文献
107.
108.
右Clifford左商半群 总被引:1,自引:0,他引:1
本文讨论了右Clifford左商半群.利用所谓的可适对刻划了右Clifford半群中的左次半群,因此扩展了商半群的研究范围. 相似文献
109.
110.