Stab-GKnock: Controlled variable selection for partially linear models using generalized knockoffs

The recently proposed fixed-X knockoff is a powerful variable selection procedure that controls the false discovery rate (FDR) in any finite-sample setting, yet its theoretical insights are difficult to show beyond Gaussian linear models. In this paper, we make the first attempt to extend the fixed-X knockoff to partially linear models by using generalized knockoff features, and propose a new stability generalized knockoff (Stab-GKnock) procedure by incorporating selection probability as feature importance score. We provide FDR control and power guarantee under some regularity conditions. In addition, we propose a two-stage method under high dimensionality by introducing a new joint feature screening procedure, with guaranteed sure screening property. Extensive simulation studies are conducted to evaluate the finite-sample performance of the proposed method. A real data example is also provided for illustration.Comment: 40 pages, 11 figures, 4 table

Room-temperature nonequilibrium growth of controllable ZnO nanorod arrays

In this study, controllable ZnO nanorod arrays were successfully synthesized on Si substrate at room temperature (approx. 25°C). The formation of controllable ZnO nanorod arrays has been investigated using growth media with different concentrations and molar ratios of Zn(NO3)2 to NaOH. Under such a nonequilibrium growth condition, the density and dimension of ZnO nanorod arrays were successfully adjusted through controlling the supersaturation degree, i.e., volume of growth medium. It was found that the wettability and electrowetting behaviors of ZnO nanorod arrays could be tuned through variations of nanorods density and length. Moreover, its field emission property was also optimized by changing the nanorods density and dimension

Silica nanospheres entrapped with ultra-small luminescent crystals for protein delivery

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Constructing smart nano-systems for intracellular delivery of functional proteins has been endeavored for diverse biomedical applications, but suffered daunting challenges. Herein silica nanospheres entrapped with photoluminescent CaF2:Tm,Yb nanocrystals were synthesized and decorated with amino molecules for protein delivery. Amino-modified nanospheres presented high protein loading capacity and sustained release phenomenon. The photoluminescence of particles highly corresponded to protein release progress. The preliminary in-vitro study confirmed markedly enhanced cell up-taking efficiency of protein molecules with the nanocomposite developed

Crystal-crystal phase transformation via surface-induced virtual premelting

A mechanism for crystal-crystal phase transformations (PTs) via surface-induced virtual premelting is justified thermodynamically and confirmed experimentally for the PTs in PbTiO3 nanofibers. When the thickness of the surface melt (which appears much below the melting temperature, especially for nano-objects) exceeds the size of the critical product nucleus, nucleation and growth of the product crystal occur. For nanowires, premelting starts near the smallest size, and hydrodynamic flow driven by reduction in the external surface leads to a large change in shape and further promotion of crystal-crystal PT. During the product crystal-growth stage, virtual melting is observed experimentally within the crystal-crystal interface

Enhanced Luminescence of Eu-Doped TiO2Nanodots

Monodisperse and spherical Eu-doped TiO2nanodots were prepared on substrate by phase-separation-induced self-assembly. The average diameters of the nanodots can be 50 and 70 nm by changing the preparation condition. The calcined nanodots consist of an amorphous TiO2matrix with Eu3+ions highly dispersed in it. The Eu-doped TiO2nanodots exhibit intense luminescence due to effective energy transfer from amorphous TiO2matrix to Eu3+ions. The luminescence intensity is about 12.5 times of that of Eu-doped TiO2film and the luminescence lifetime can be as long as 960 μs

Crystal-crystal phase transformation via surface-induced virtual premelting

A mechanism for crystal-crystal phase transformations (PTs) via surface-induced virtual premelting is justified thermodynamically and confirmed experimentally for the PTs in PbTiO3 nanofibers. When the thickness of the surface melt (which appears much below the melting temperature, especially for nano-objects) exceeds the size of the critical product nucleus, nucleation and growth of the product crystal occur. For nanowires, premelting starts near the smallest size, and hydrodynamic flow driven by reduction in the external surface leads to a large change in shape and further promotion of crystal-crystal PT. During the product crystal-growth stage, virtual melting is observed experimentally within the crystal-crystal interface.This article is from Physical Review B 85 (2012): 220104(R), doi:10.1103/PhysRevB.85.220104. Posted with permission.</p

Evolution and Mechanism of Cesium Lead Bromide Nanostructures in Oleylamine‐Rich System by Hot‐Injection Method

Abstract Due to the ultrafast nucleation and growth rates of perovskite nanostructures during the synthesis, the products are difficult to control, such as its derivatives (e.g., Cs4PbBr6) often appear. Here, the hot‐injection method is ameliorated by using oleylamine (OAm) instead of octadecene as solvent. The results reveal that in OAm‐rich system, the pure nanostructures with different Pb/Br ratios (CsBr, Cs4PbBr6, and CsPbBr3) can be obtained at different reaction temperatures, and thus controlling the Pb‐Br linkage and the interconnection of [PbBr6]4− octahedra, and resulting in the formation of different nanostructures. As the reaction temperature increases from 120 to 180 °C, the products change from lead‐free CsBr nanocrystals to poor‐lead Cs4PbBr6 nanocrystals and finally to normal CsPbBr3 nanocubes and nanowires. Moreover, the synthesized CsPbBr3 nanowires exhibit an emission peak at 521 nm, full width at half maximum (FWHM) of 19 nm, with photoluminescence quantum yields (PLQY) of 64.9%, and high stability. Furthermore, the white light‐emitting diode (WLED) devices are successfully fabricated based on the obtained CsPbBr3 nanowires, showing high‐intensity white light and high stability without any encapsulation. Remarkably, this work provides a new approach for elucidating the synthesis mechanism of perovskite nanomaterials and their applications