نتایج جستجو برای: boron nitride crown ethers

تعداد نتایج: 53535  

2015
Subash Sharma Golap Kalita Riteshkumar Vishwakarma Zurita Zulkifli Masaki Tanemura

In-plane heterostructure of monolayer hexagonal boron nitride (h-BN) and graphene is of great interest for its tunable bandgap and other unique properties. Here, we reveal a H2-induced etching process to introduce triangular hole in triangular-shaped chemical vapor deposited individual h-BN crystal. In this study, we synthesized regular triangular-shaped h-BN crystals with the sizes around 2-10...

Journal: :Physical review letters 2007
J Serrano A Bosak R Arenal M Krisch K Watanabe T Taniguchi H Kanda A Rubio L Wirtz

The phonon dispersion relations of bulk hexagonal boron nitride have been determined from inelastic x-ray scattering measurements and analyzed by ab initio calculations. Experimental data and calculations show an outstanding agreement and reconcile the controversies raised by recent experimental data obtained by electron-energy loss spectroscopy and second-order Raman scattering.

Journal: :Bioinorganic Chemistry and Applications 2003
Edgars Abele Ramona Abele Pavel Arsenyan Irina Shestakova Iveta Kanepe Inga Antonenko Juris Popelis Edmunds Lukevics

Silicon and germanium containing pyridine aldoxime, ketoxime and amidoxime O-ethers have been prepared using phase transfer catalytic systems oxime alkyl halide solid KOH 18-crown-6 benzene and oxime alkyl halide solid K(2)CO(3) or Cs(2)CO(3) 18-crown-6 toluene. Cytotoxic activity of silicon and germanium containing pyridine oxime O-ethers was tested in vitro on two monolayer tumor cell lines: ...

Journal: :Dalton transactions 2014
Valeri Leich Kevin Lamberts Thomas P Spaniol Jun Okuda

Alkali metal triphenylsilyls [Li(12-crown-4)SiPh3]·(thf)0.5 (2), [Na(15-crown-5)SiPh3]·(thf)0.5 (3) and [K(18-crown-6)SiPh3(thf)] (4) were synthesized using 1,1,1-trimethyl-2,2,2-triphenyldisilane (Ph3SiSiMe3) and isolated in high yields. Solid state structures were determined by single crystal X-ray diffraction. These alkali metal silyls catalyzed the regioselective hydrosilylation of 1,1-diph...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2009
Cheehuei Lee Jaroslaw Drelich Yokekhin Yap

Partially vertical aligned boron nitride nanotubes (BNNTs) on Si substrates are found to be superhydrophobic in contrast to boron nitride (BN) thin films. While the hexagonal-phase BN films are partially wetted by water with advancing contact angle of about 50 degrees , partially vertically aligned BNNTs can achieve superhydrophobic state with advancing water contact angle exceeding 150 degrees...

Journal: :Physical chemistry chemical physics : PCCP 2014
Yunfang Li

Molecular mechanics results show that a hexagonal boron nitride (h-BN) membrane can spontaneously assemble on the single-walled boron nitride nanotube (BNNT) in a scroll or helical manner, showing an interesting dependence on h-BN width. The size of BNNTs should meet the required conditions to guarantee self-assembly. Further analyses of energy components and structural geometry show that this ...

Journal: :The Journal of chemical physics 2015
Yasmine S Al-Hamdani Ming Ma Dario Alfè O Anatole von Lilienfeld Angelos Michaelides

Despite a recent flurry of experimental and simulation studies, an accurate estimate of the interaction strength of water molecules with hexagonal boron nitride is lacking. Here, we report quantum Monte Carlo results for the adsorption of a water monomer on a periodic hexagonal boron nitride sheet, which yield a water monomer interaction energy of -84 ± 5 meV. We use the results to evaluate the...

2013
T. P. Kaloni M. Tahir U. Schwingenschlögl

We study a superlattice of silicene and hexagonal boron nitride by first principles calculations and demonstrate that the interaction between the layers of the superlattice is very small. As a consequence, quasi free-standing silicene is realized in this superlattice. In particular, the Dirac cone of silicene is preserved. Due to the wide band gap of hexagonal boron nitride, the superlattice re...

2005
C. W. Chang A. Zettl

We have measured the temperature-dependent thermal conductivity T of boron-carbon-nitride B-C-N and boron nitride BN nanotube mats. The thermal conductivity of B-C-N nanotubes is phonon dominated and reflects dimensional effect below 70 K. We employ a new analysis method to estimate the intrinsic T of BN nanotubes converted from B-C-N nanotubes, and find that at room temperature T of a multiwal...

Journal: :ACS applied materials & interfaces 2015
Bishnu Tiwari Dongyan Zhang Dustin Winslow Chee Huei Lee Boyi Hao Yoke Khin Yap

We demonstrate a universal approach to extract one- and two-dimensional nanomaterials from contaminated water, which is based on a microscopic oil-water interface trapping mechanism. Results indicate that carbon nanotubes, graphene, boron nitride nanotubes, boron nitride nanosheets, and zinc oxide nanowires can be successfully extracted from contaminated water at a successful rate of nearly 100...

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