Search results for "Icon"

Über gemischte gruppe 14-gruppe 14-bindungen

1993

Abstract The six title compounds have been synthesized from Li/KSi/GePh 3 and chloride precursors in THF, DME or diethyl ether at low temperature. The six compounds crystallize isomorphously in the space group Pbca with ordered arrangement for the four symmetrical cases (SiSi 2.394, SiGe 2.412, GeGe 2.440 A) and statistical alignment for the two asymmetrical chains; angle range 116.5–123.3°. Replacement of Si by Ge atoms leads to low field NMR chemical shifts for 13 C ipso atoms and for directly bonded 29 Si atoms. This is in accordance with an enhanced electronegativity of germanium in comparison with silicon. UV/Vis and IR/Raman data are given.

Surface AFM microscopy of unworn and worn samples of silicone hydrogel contact lenses

2008

Abstract: Purpose. To evaluate the qualitative and quantitative topographic changes in the surface of worn contact lenses (CLs) of different materials using atomic force microscopy (AFM). Methods. The topography of five different CL materials was evaluated withAFM over a surface of 25 lm2 according to previously published experimental setup. Average roughness (Ra) and root mean square (Rms) values were obtained for unworn and worn samples. Results. The Ra value increased for balafilcon A (11.62–13.68 nm for unworn and worn samples, respectively), lotrafilcon A (3.67–15.01 nm for unworn and worn samples, respectively), lotrafilcon B (4.08–8.42 nm for unworn and worn samples, respectively), g…

The structure and stoichiometry of C-S-H

2004

Abstract This review relates to the models describing the structural evolution of calcium silicate hydrate (C-S-H) at the crystal–chemical level as a function of composition in terms of calcium to silicon ratio. The different models are compared and discussed in the light of recent spectroscopic and microscopic data. Taking into account the structure and the morphological properties of C-S-H, a surface reaction thermodynamic model has been proposed and discussed to predict and correlate the chemical and structural evolution of C-S-H with solution chemistry.

Applicability of LES turbulence modeling for CZ silicon crystal growth systems with traveling magnetic field

2010

Abstract To examine the applicability of LES turbulence modeling for CZ silicon crystal growth systems with traveling magnetic fields, LES calculations with Smagorinsky–Lilly turbulence model and van Driest damping at the solid walls are carried out. The program package for the calculations was developed on the basis of the open-source code library OpenFOAM ® . A previously published laboratory model with low temperature melt InGaSn, a 20” crucible, and process parameters corresponding to industrial Czochralski silicon systems is considered. Flow regimes with two crystal and crucible rotation rates and with different strengths of the traveling magnetic field “down” are analyzed. The calcula…

Ultrasensitive Silicon Nanowire for Real-World Gas Sensing: Noninvasive Diagnosis of Cancer from Breath Volatolome

2014

We report on an ultrasensitive, molecularly modified silicon nanowire field effect transistor that brings together the lock-and-key and cross-reactive sensing worlds for the diagnosis of (gastric) cancer from exhaled volatolome. The sensor is able to selectively detect volatile organic compounds (VOCs) that are linked with gastric cancer conditions in exhaled breath and to discriminate them from environmental VOCs that exist in exhaled breath samples but do not relate to the gastric cancer per se. Using breath samples collected from actual patients with gastric cancer and from volunteers who do not have cancer, blind analysis validated the ability of the reported sensor to discriminate betw…

Electrical Resistivity Anisotropy of Silicon-Doped n-Indium Selenide

1993

Cathodoluminescence of Ge+, Si+, and O+ implanted SiO2 layers and the role of mobile oxygen in defect transformations

2002

Abstract Thermally grown SiO 2 layers of thickness d =500 nm have been implanted by Ge + , Si + , and O + ions of energy 350, 150, and 100 keV, respectively, and a uniform implantation dose of D i =5×10 16 ions/cm 2 . Thus the implantation profiles are expected with a concentration maximum of nearly 4 at.% at the half-depth d m ≅250 nm of the SiO 2 layers. After thermal annealing to 900 °C for 1 h in dry nitrogen or vacuum the typical violet luminescence band ( λ =400 nm) of the Ge + implanted centers is increased more than 200-fold and the Ge luminescent center depth profile is shifted from about 250 to 170 nm towards the surface as determined by cathodoluminescence (CL) depth profiling. I…

Performance assessment of a grid-connected mc-Si PV system made up of silicon material from different manufacturing routes

2013

Summarises the performance of an Elkem Solar photovoltaic (PV) system installed in the Sunbelt Region (between 35 North and 35 South) in Hyderabad, India, which has been fully operational since August 2012. The PV system consists of 28 multicrystalline silicon PV modules made from the standard Siemens process and from material produced by a metallurgical route - the Elkem Solar Silicon (ESS™) process. A comparative performance study of the ESS™ modules with respect to standard polysilicon has been carried out under the various climatic and solar radiation conditions at the location. The present study suggests that the ESS™ PV modules have a slightly better performance than standard polysili…

Decomposition of peroxy radicals in SiO 2 glass with X‐rays or KrF laser light

2005

Decomposition of the peroxy radical (POR) was examined for wet SiO 2 glasses exposed to X-rays from a Rh-target tube or KrF laser light. The exposure to KrF laser light destroys POR resulting in the selective formation ofthe oxygen dangling bond (termed "non-bridging oxygen hole center", NBOHC). In contrast, the exposure to X-rays creates both the silicon dangling bond (E' center) and NBOHC on bleaching of POR. Clear mutual correlation is found between the formation kinetics of the interstitial oxygen molecule (O 2 ) and of the Si-Si bond but not between those of O 2 and the E' center. These observations indicate that O 2 is created mainly from the radiolysis of the Si-O-Si bond by the Fren…

Coordination environment friendly silicon in copper(I) chloride π-complexes with tetravinylsilane and dimethyltetravinyldisiloxane

2011

Abstract Two crystal complexes of copper(I) chloride with tetravinylsilane (TVS) dimethyltetravinyldisiloxane (DMTVDS) were prepared and examined by IR spectroscopy and X-ray diffraction: sp. gr. P2/a, Z = 4, a = 13.428(1) A, b = 7.9584(7) A, c = 14.694(1) A for [Cu4Cl4(TVS)]; sp. gr. P21/c, a = 10.505(1) A, b = 13.487(1) A, c = 13.870(1) A for [Cu4Cl4(DMTVDS)]. The influence of the vinylsilicon ligands on the efficiency of the Cu⋯C C interaction is discussed. Thus, the consideration of dSi ← π∗C C ← dCu conjugate system may help to understand how the silicon π-acceptor properties influence on the degree of trigonal distortion of the Cu(I) coordination tetrahedron as well as on the inorgani…