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121.
We consider the treatment comparison problem in a general high-dimensional regression setting. In this article, we propose a nonparametric estimation approach based on partial sliced inverse regression (SIR) (Chiaromonte et al. in Ann Stat 30:475–497, 2002) and an extension of partial inverse mean matching (Carroll and Li in Stat Sin 5:667–688, 1995) without requiring a prespecified parametric model. A sparse estimation strategy is incorporated in our approach to enhance the interpretation of variable selection. Several simulation examples are used to compare our method with SIR and principal components analysis. Illustrative applications to two real datasets are also presented. 相似文献
122.
Solid materials with cracks exhibit the nonclassical nonlinear acoustical behavior. The micro-defects in solid materials can be detected by nonlinear elastic wave spectroscopy (NEWS) method with a time-reversal (TR) mirror. While defects lie in viscoelastic solid material with different distances from one another, the nonlinear and hysteretic stress-strain relation is established with Preisach-Mayergoyz (PM) model in crack zone. Pulse inversion (PI) and TR methods are used in numerical simulation and defect locations can be determined from images obtained by the maximum value. Since false-positive defects might appear and degrade the imaging when the defects are located quite closely, the maximum value imaging with a time window is introduced to analyze how defects affect each other and how the fake one occurs. Furthermore, NEWS-TR- NEWS method is put forward to improve NEWS-TR scheme, with another forward propagation (NEWS) added to the existing phases (NEWS and TR). In the added phase, scanner locations are determined by locations of all defects imaged in previous phases, so that whether an imaged defect is real can be deduced. NEWS-TR-NEWS method is proved to be effective to distinguish real defects from the false-positive ones. Moreover, it is also helpful to detect the crack that is weaker than others during imaging procedure. 相似文献
123.
Hua Wu Yu‐Ping He Lue Xu Dong‐Yang Zhang Liu‐Zhu Gong 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(13):3534-3537
An asymmetric organocatalytic direct C H/C H oxidative coupling reaction of N1,N3‐diphenylmalonamides has been well established by using chiral organoiodine compounds as catalysts, wherein four C H bonds were stereoselectively functionalized to give structurally diverse spirooxindoles with high levels of enantioselectivity. More importantly, the findings indicated that chiral hypervalent organoiodine reagents can serve as alternative catalysts for the creation of enantioselective functionalization of inactive C H bonds. 相似文献
124.
Multistimuli‐Responsive Supramolecular Assembly of Cucurbituril/Cyclodextrin Pairs with an Azobenzene‐Containing Bispyridinium Guest 下载免费PDF全文
Jin Zhao Dr. Ying‐Ming Zhang He‐Lue Sun Xiao‐Yu Chang Prof. Dr. Yu Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(46):15108-15115
A linear supramolecular architecture was successfully constructed by the inclusion complexation of α‐cyclodextrin with azobenzene and the host‐stabilized charge‐transfer interaction of naphthalene and a bispyridinium guest with cucurbit[8]uril in water, which was comprehensively characterized by 1H NMR spectroscopy, UV/Vis absorption, fluorescence, circular dichroism spectroscopy, dynamic laser scattering, and microscopic observations. Significantly, because it benefits from the photoinduced isomerization of the azophenyl group and the chemical reduction of bispyridinium moiety with noncovalent connections, the assembly/disassembly process of this supramolecular nanostructure can be efficiently modulated by external stimuli, including temperature, UV and visible‐light irradiation, and chemical redox. 相似文献
125.
Asymmetric Organocatalytic Direct C(sp2)H/C(sp3)H Oxidative Cross‐Coupling by Chiral Iodine Reagents 下载免费PDF全文
Hua Wu Yu‐Ping He Lue Xu Dong‐Yang Zhang Prof. Liu‐Zhu Gong 《Angewandte Chemie (International ed. in English)》2014,53(13):3466-3469
An asymmetric organocatalytic direct C? H/C? H oxidative coupling reaction of N1,N3‐diphenylmalonamides has been well established by using chiral organoiodine compounds as catalysts, wherein four C? H bonds were stereoselectively functionalized to give structurally diverse spirooxindoles with high levels of enantioselectivity. More importantly, the findings indicated that chiral hypervalent organoiodine reagents can serve as alternative catalysts for the creation of enantioselective functionalization of inactive C? H bonds. 相似文献
126.
De‐Heng Shi Wei Xing Jin‐Feng Sun Zun‐Lue Zhu Yu‐Fang Liu 《International journal of quantum chemistry》2012,112(5):1323-1342
The potential energy curves (PECs) of A3Σ, B3Πg, W3Δu, and B′3Σ electronic states of the N2 molecule have been studied for internuclear separations from 0.05 to 2.0 nm using the full valence complete active space self‐consistent‐field method followed by the highly accurate valence internally contracted multireference configuration interaction (MRCI) approach in conjunction with the correlation‐consistent basis sets. Effects on the PECs by the core–valence correlation and relativistic corrections are taken into account. The way to consider the relativistic correction is to use the second‐order Douglas‐Kroll Hamiltonian approximation. The core–valence correlation correction is made with the cc‐pCV5Z basis set. And the relativistic correction is performed at the level of cc‐pV5Z basis set. To obtain more reliable results, the PECs determined by the MRCI calculations are also corrected for size‐extensivity errors by the Davidson modification (MRCI+Q). These PECs are extrapolated to the complete basis set limit. The spectroscopic parameters of 14N2, 14N15N, and 15N2 isotopologs have been evaluated and compared with those reported in the literature. Excellent agreement has been found between the present results and the Rydberg‐Klein‐Rees (RKR) data. With the PECs obtained by the MRCI+Q/CV+DK+56 calculations, the first 30 vibrational states for three species are computed for each electronic state. And for each electronic state of each species, the vibrational level G(ν), inertial rotation constant Bν, and centrifugal distortion constant Dν have been determined, which agree well with the RKR data. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012 相似文献
127.
EDXRF微量元素分析在文物断源断代中的研究 总被引:1,自引:0,他引:1
能量色散X荧光分析(EDXRF)是重要的元素成分析方法之一,现已成为一种强有力的定性和精确定量的无损分析测试技术。能量色散X荧光分析(EDXRF)技术具有不破坏分析样品,并能快速进行钠(Z11)至铀(Z92)的多元素的同时分析,以及分析的浓度范围宽广,精度高等特点,因此,特别适合于进行文物材料的成分分析研究,尤其适合测试极其珍贵的古陶瓷完整文物样品分析与鉴定。文章运用该方法对选自杭州南宋官窑窑址、龙泉古窑址出土的14个样品的南宋官窑青瓷、南宋龙泉窑青瓷和现代仿古青瓷等进行了元素分析的对比研究,分析测定古陶瓷样品中胎、釉的主、次量及微量元素组成,寻找组成中的“指纹”特征元素,试图为古陶瓷文物的断源、断代研究和真伪鉴定提供科学依据。研究结果表明能量色散X荧光分析(EDXRF)是一种较理想的文物研究和鉴定的科学分析手段。 相似文献
128.