Étude structurale de britholite au césium Sr7La2Cs(PO4)5(SiO4)F2

Several studies demonstrated the ability of britholites to retain radionuclides such as the caesium and actinides. Therefore, three compounds with formulas Sr₈LaCs(PO₄)₆F₂, Sr₇La₂Cs(PO₄)₅(SiO₄)F₂ and Sr₂La₇Cs(SiO₄)₆F₂, were prepared by solid state reaction. However, it seems that only the mono-silicated composition was obtained in a pure state. In this present work, the X-ray diffraction and magnetic nuclear resonance have been used to investigate the structure for this composition. The results showed that in fact this phase was not pure, but it was mixed with a secondary phase, SrLaCs(PO₄)₂. The refinement by the Rietveld method allowed also to precise the distribution of La³⁺ and Cs⁺ ions between the two cationic sites of the apatite.     

强激光条件下5CB液晶中的激光诱导衍射环现象

强激光经5CB液晶传播时会产生非线性自相位调制现象,利用532 nm和1 064 nmCW激光研究了强激光条件下5CB液晶中的激光诱导衍射环现象,并对强激光在5CB液晶中产生自相位调制的现象和机理进行了讨论.当532 nm激光和1 064 nm激光功率密度分别大于10 kW/cm2和300W/cm2时,接收白屏上有较明...     

Incomplete active polarimetry: Measurement of the block-diagonal scattering matrix

The problem of measurement of block-diagonal scattering matrix as being part of the so-called incomplete or partial Mueller polarimetry is addressed. It has been shown that non-zero elements of the scattering matrix with block-diagonal structure can be measured using only two elliptical polarizations of input light. Optimal pairs of these polarizations are derived. Utilization of the optimal input polarizations results in halving measurement time and decreasing measurement errors by 30%.     

Regularization of jump points in applying the adaptive spatial resolution technique

The performance of the adaptive spatial resolution technique is improved by making the resolution function of the coordinate transformation as smooth as possible. To this end, the smoothness of the resolution function is probed and a quantitative criterion is proposed to make the jump points; which were conventionally equidistant from each other, regularized. The here-proposed regularization is applied to two different recent formulations and its effects on the overall convergence rate and on the presence of numerical artifacts in analysis of highly conducting gratings are studied. Dielectric and metallic gratings at optical and microwave frequencies are considered and the helpfulness of the proposed technique is discussed.     

A non-dimensional approach to diffraction phenomena in the Fresnel approximation

The paper presents a theoretical and numerical study of the diffraction problem approached in the Fresnel approximation. The problem was formulated by a non-dimensional approach, which implies the definition of two non-dimensional quantities: F and ζ. In particular the parameter F is the well-known Fresnel number, whose value was usually used to classify diffraction regime. In analyzing the numerical approach some limitations imposed by the discretization arise; in particular these limitations constrain the level of sampling to be used for the diffracting field by requiring more and more elements when the diffraction conditions become more severe — i.e. increasing the dimension of the diffracting aperture and/or decreasing the distance of the plane where the diffracted field is observed.     

Regularity of the inverse of a homeomorphism with finite inner distortion

Let f:Ω→ f(Ω) R~n be a W~(1,1)-homeomorphism with L~1-integrable inner distortion.We show that finiteness of min{lip_f(x),k_f/(x)},for every x ∈Ω\E,implies that f~(-1) ∈ W~(1,n)and has finite distortion,provided that the exceptional set E has cr-finite H~1-measure.Moreover,/ has finite distortion,differentiable a.e.and the Jacobian J_f 0 a.e.     

基于CVaR准则的折扣回购策略双层风险决策

首先,引入条件风险值(CVaR)准则,作为风险厌恶型的供应商和零售商的决策准则,建立了基于条件风险值(CVaR)准则的折扣回购策略双层风险决策模型.然后,导出了零售商在批发价格下的最优订购公式,证明了订购量随着折扣增大而增大,随着批发价格增大而减小,数值实验表明供应商可以通过折扣和批发价来分担零售商的风险损失,来使供应链达到协调.     

带约束条件和多余参数的线性模型的比较

对于带约束条件和多余参数的两个线性模型ｅ１＝Ｌ（Ｘ１β＋Ｚ１γ，Ｖ１，Ｌ１）和ｄ２＝Ｌ（Ｘ２β＋Ｚ２δ，Ｖ２，Ｌ２），其中Ｖ１和Ｖ２是已知对称的正定矩阵，γ和δ是多余参数，Ｌ１和Ｌ２是已知的约束矩阵，文中给出了一种新的比较准则，并得到了几个充要条件。     

Synthesis of ZnO nanospheres with uniform nanopores by a hydrothermal process

ZnO nanospheres were successfully synthesized by a hydrothermal process (S1 sample) and a wet-chemical method (S2 sample). Following synthesis, calcination treatment at 450 °C was performed for the sample prepared by the wet-chemical method (S3 sample). All of the samples possessed a regular spherical shape. A polycrystalline wurtzite structure was confirmed in the S1 and S3 samples by X-ray diffraction and selected area electron diffraction, whereas a mixture of ZnO nanoparticles and amorphous materials was observed in the sample S2. The surface area and pore structure of the samples were investigated by nitrogen adsorption–desorption measurements. Uniform nanopores with a diameter of 4.07 nm were present in the S1 sample while a broad pore size distribution was obtained for the S2 and S3 samples. The highest surface area was obtained for the S1 sample and a possible formation mechanism was studied.