نتایج جستجو برای: silicon substitution
تعداد نتایج: 137468 فیلتر نتایج به سال:
The reductive cleavage of the Si-Si bond in 1,1-bis(1-methyl-2,3,4,5-tetraphenyl-1-silacyclopentadiene) [(C(4)Ph(4)SiMe)(2)] (1) with either Li or Na in THF gives the silole anion [MeSiC(4)Ph(4)]- (2). The head-to-tail dimerization of the silole anion 2 gives crystals of the disilatricyclic diallylic dianion [(C(4)Ph(4)SiMe)(2)]-2 (3). The derivatization of 3 (crystals) with bromoethane (gas) u...
To further investigate the α-effect in silanes bearing a geminal donor atom, the model compounds (C2F5)3SiCH2NMe2, (C2F5)3SiCH2OMe and (C2F5)3SiONMe2 were prepared by introduction of pentafluoroethyl groups via nucleophilic substitution of the corresponding chloro-derivatives with pentafluoroethyl lithium. The substances were characterised by NMR spectroscopy and X-ray diffraction via in situ c...
BACKGROUND: Silicon is a suitable solution to alleviate salinity stress and improve crop production. OBJECTIVES: Investigation physiological and biochemical traits of Single Cross 704 corn affected foliar application of silicon (from a Sodium silicate source) under salinity stress. METHODS: This research was carried out according sp...
In this paper, synthesis of inverted nano-pyramids on a single crystal silicon surface through a simple and cost-effective wet chemical method is surveyed. These structures were synthesized by MACE process using Cu as the assisted metal in the solution of copper nitrate, hydrogen peroxide and hydrofluoric acid for different etching times. FE-SEM images of the samples show that time is an import...
Silica (SiO(2)) and the silicate-based biomaterials play an important role due to their in vitro and in vivo biological response. The present study synthesized a novel nano-structured amorphous silica doped hydroxyapatite (HA) via an aqueous precipitation route. HA was prepared with 0, 1, 3 and 5 wt% silica, which are comparable to the measured silicon content of natural bone. After spray dryin...
A range of crystalline and nano-sized carbonate- and silicate-substituted hydroxyapatite has been successfully produced by using continuous hydrothermal flow synthesis technology. Ion-substituted calcium phosphates are better candidates for bone replacement applications (due to improved bioactivity) as compared to phase-pure hydroxyapatite. Urea was used as a carbonate source for synthesising p...
Porous Silicon (PS) layers have been prepared from p-type silicon wafers of (100) orientation. SEM, XRD, FTIR and PL studies were done to characterize the surface morphological and optical properties of PS. The porosity of the PS samples was determined using the parameters obtained from SEM images by geometric method. The refractive index values of the PS samples as a function of poros...
Microgreens are young plants that have gained popularity among consumers due to their high nutritional value. In the present study, the shelf life and nutritional properties of beet microgreens subjected to silicon and nano-silica in the post-harvest period have been investigated. Silicon and nano-silica treatments were carried out at two levels (Control and 100 mg/L as foliar spraying), after ...
despite the body of research on textbook evaluation from the discourse analysis perspective, cohesive devices have rarely been analyzed in english for specific purposes (esp) textbooks. the acquisition and use of cohesive devices is inherent to naturalistic communication, including business interactions. hence, l2 learners of business english should be exposed to these devices through cohesion-...
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