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671.
利用重复观测数据和加权方法给出了有重复观测时变系数一维线性结构关系EV模型中的参数估计,证明了估计的弱相合性和强相合性. 相似文献
672.
On Kendall's Process 总被引:1,自引:0,他引:1
Philippe Barbe Christian Genest Kilani Ghoudi Bruno Rémillard 《Journal of multivariate analysis》1996,58(2):197-229
LetZ1, …, Znbe a random sample of sizen?2 from ad-variate continuous distribution functionH, and letVi, nstand for the proportion of observationsZj,j≠i, such thatZj?Zicomponentwise. The purpose of this paper is to examine the limiting behavior of the empirical distribution functionKnderived from the (dependent) pseudo-observationsVi, n. This random quantity is a natural nonparametric estimator ofK, the distribution function of the random variableV=H(Z), whose expectation is an affine transformation of the population version of Kendall's tau in the cased=2. Since the sample version ofτis related in the same way to the mean ofKn, Genest and Rivest (1993,J. Amer. Statist. Assoc.) suggested that[formula]be referred to as Kendall's process. Weak regularity conditions onKandHare found under which this centered process is asymptotically Gaussian, and an explicit expression for its limiting covariance function is given. These conditions, which are fairly easy to check, are seen to apply to large classes of multivariate distributions. 相似文献
673.
利用吩噁嗪和嘧啶分别作为电子给体和电子受体,通过Buchwald-Hartwig和Suzuki偶联反应成功合成了一种热活化延迟荧光黄光材料pPBPXZ.密度泛函理论计算显示,pPBPXZ分子中吩噁嗪和嘧啶结构单元间的二面角接近90°,而两个嘧啶结构单元与连接二者的苯环间的二面角接近0°;pPBPXZ的最高电子占据轨道主要分布在吩噁嗪结构单元上,最低电子未占轨道主要分布在嘧啶环和苯环上,两种分子轨道只有很小部分重叠.循环伏安、热重和差热测试表明,pPBPXZ具有高的电化学稳定性和热稳定性.在甲苯溶液中,pPBPXZ在360~495 nm显示出了明显的分子内电荷转移跃迁吸收,室温发光峰出现在535 nm.根据低温(77 K)荧光和磷光光谱,计算得到pPBPXZ的最低激发单重态和最低激发三重态能级分别为2.57 eV和2.48 eV,能级差(△EST)仅为0.09 eV.利用pPBPXZ作为发光层客体掺杂材料,制备出了高效率的黄光电致发光器件.器件的发射峰出现在552~560 nm,最大电流效率、功率效率和外量子效率分别达到了49.9 cd/A、49.0 lm/W和15.7%,而且发光效率受pPBPXZ掺杂浓度影响较小. 相似文献
674.
聚合物热激活延迟荧光(TADF)材料应用于有机发光二极管(OLEDs)中以来,取得了飞速发展,迄今为止已经报道了多种不同分子结构及性能优异的聚合物TADF发光材料.它们具有不含重金属的化学结构、100%的理论内量子效率和易于通过溶液加工进行大面积制造的优势.本文从分子结构和发光颜色2个角度总结了不同结构TADF聚合物的研究进展,重点介绍了我们课题组在长链型TADF聚合物设计与OLEDs器件性能方面的研究工作,探究TADF聚合物颜色调控与效率提升的途径,论述了TADF聚合物存在的问题与未来发展. 相似文献
675.
Wolfgang Bischoff 《Annals of the Institute of Statistical Mathematics》1992,44(2):229-238
Let * be an exact D-optimal design for a given regression model Y
= X
+ Z
. In this paper sufficient conditions are given for sesigning how the covariance matrix of Z
may be changed so that not only * remains D-optimal but also that the best linear unbiased estimator (BLUE) of stays fixed for the design *, although the covariance matrix of Z
* is changed. Hence under these conditions a best, according to D-optimality, BLUE of is known for the model with the changed covariance matrix. The results may also be considered as determination of exact D-optimal designs for regression models with special correlated observations where the covariance matrices are not fully known. Various examples are given, especially for regression with intercept term, polynomial regression, and straight-line regression. A real example in electrocardiography is treated shortly. 相似文献
676.
A. A. Sukhodola 《Journal of Applied Spectroscopy》2008,75(4):527-531
Spectral and kinetic characteristics of delayed luminescence of indole derivatives in the gas phase have been studied. The
mechanism for delayed luminescence has been shown to depend on the disposition of the two lowest excited singlet ππ*-states,
1La and 1Lb. For vapors of 3-methyl-and 2,3-dimethylindole having a small 1La-2Lb energy gap ΔE (ΔE < 500 cm−1), prolonged light emissions with maxima at 525 and 540 nm, respectively, have been observed and interpreted as luminescence
of free radicals formed due to dissociation of an N-H bond. For vapors of 5-methoxyindole having ΔE ≈ 3700 cm−1, annihilation of delayed luminescence has been observed. The lifetimes for triplet states of 3-methyl-, 2,3-dimethyl-, and
5-methoxyindole at T = 373 K equal to 30, 26, and 65 μsec, respectively, were calculated from the kinetics of the delayed
luminescence.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 4, pp. 503–508, July–August, 2008. 相似文献
677.
N. A. Borisevich A. A. Sukhodola G. B. Tolstorozhev 《Journal of Applied Spectroscopy》2007,74(3):379-384
We have studied the spectral characteristics and the kinetics of delayed (long-lived) luminescence of N-methylindole and indole
in the gas phase. For N-methylindole, we observed delayed annihilation fluorescence, spectrally matching fast fluorescence.
There is no delayed annihilation fluorescence for indole, but we observed a delayed luminescence band with wavelength at the
maximum 535 nm, which we interpreted as luminescence of free radicals formed as a result of dissociation of the N-H bond.
We hypothesize that the excited states of the free radicals arise as a result of nonradiative energy transfer from indole
in the triplet state to indole free radicals in the doublet state. The lifetimes of the triplet states of N-methylindole and
indole in the gas phase at T = 373 K, obtained from analysis of the delayed luminescence kinetics, are 2.5 msec and 1.0 msec.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 3, pp. 341–345, May–June, 2007. 相似文献
678.
T. Funaki 《数学学报(英文版)》1999,15(3):407-438
Singular limit is investigated for reaction-diffusion equations with an additive noise in a bounded domain of ℝ2. The solution converges to one of the two stable phases {+1, −1} determined from the reaction term; accordingly a phase separation
curve is generated in the limit. We shall derive a randomly perturbed motion by curvature for the dynamics of the phase separation
curve. 相似文献
679.
One or few observations can be highly influential on estimates of regression coefficients in the linear regression model.
In this paper we derive influence diagnostics for the varying coefficients model with longitudinal data. We note that diagnostics
in this context is quite different from the classical regression model in the sense that regression coefficients vary as time
varies. A version of Cook’s distance is suggested to reflect this specific aspect of varying coefficient model. An algorithm
to present some guidelines to determine influential observations deserving special attention is developed. An illustrative
example based on the AIDS data is also given. 相似文献
680.
D. A. Slavnov 《Theoretical and Mathematical Physics》2008,155(2):789-801
We discuss the locality problem in relativistic and nonrelativistic quantum theory. We show that there exists a formulation
of quantum theory that, on one hand, preserves the mathematical apparatus of the standard quantum mechanics and, on the other
hand, ensures the satisfaction of the locality condition for each individual event including the measurement procedure. As
an example, we consider the scattering from two slits.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 155, No. 2, pp. 327–343, May, 2008. 相似文献