نتایج جستجو برای: silica boron

تعداد نتایج: 55027  

2001
Daniel Macdonald Andrés Cuevas Jennifer Wong-Leung

Injection-level dependent recombination lifetime measurements of iron-diffused, boron-doped silicon wafers of different resistivities are used to determine the electron and hole capture cross sections of the acceptor level of iron–boron pairs in silicon. The relative populations of iron–boron pairs and interstitial iron were varied by exposing the samples to different levels of illumination pri...

2010
Amir Hossein Tavakoli

Amorphous Si–(B–)C–N polymer-derived ceramics (PDCs) with a boron contentranging from 0 to 8.3 at.% were synthesized by thermolysis of the boron-modifiedpoly(methylvinylsilazane). Correlation of the boron content and the thermal stability ofthese materials in the course of annealing were investigated using high temperaturethermal gravimetric analysis (HT-TGA). Furthermore, t...

Journal: :Plant physiology 1966
R Y Yih F K Hille H E Clark

Ginkgo biloba L. pollen-derived tissue, which is made up of small, friable masses of homogeneous parenchymatous cells, was shown to require boron in the culture medium. If no boron is supplied, growth soon stops. Growth responses to additions of boron were observed up to an optimum level of 0.1 mg of boron per liter.Histological examination and chemical analyses showed 2 general effects of boro...

2017
Naoyuki Sotta Susan Duncan Mayuki Tanaka Takafumi Sato Athanasius Fm Marée Toru Fujiwara Verônica A Grieneisen

Nutrient uptake by roots often involves substrate-dependent regulated nutrient transporters. For robust uptake, the system requires a regulatory circuit within cells and a collective, coordinated behaviour across the tissue. A paradigm for such systems is boron uptake, known for its directional transport and homeostasis, as boron is essential for plant growth but toxic at high concentrations. I...

Journal: :Nanoscale 2010
Jifa Tian Zhichuan Xu Chengmin Shen Fei Liu Ningsheng Xu Hong-Jun Gao

One-dimensional (1D) boron nanostructures are very potential for nanoscale electronic devices since their physical properties including electric transport and field emission have been found very promising as compared to other well-developed 1D nanomaterials. In this article, we review the current progress that has been made on 1D boron nanostructures in terms of theoretical prediction, syntheti...

2017
Zhifen Luo Xiaoli Fan Yurong An

Very recently, borophene (atomic-thin two-dimensional boron sheet) has been successfully synthesized on the Ag(111) surface by deposition. Two kinds of structures were found. However, the identification of the monolayer boron sheets grown on the metal substrate, as well as the stability of different 2D boron sheets, is controversial. By performing the first-principles calculations, present stud...

2009
D. P. Dandekar J. A. Ciezak

Our present work presents a direct association of the observed loss of shear strength in boron carbide under plane shock wave compression to amorphization in boron carbide under triaxial stress compression. This evidence is obtained from in-situ measurement of Raman, and infrared vibrational spectra of boron carbide confined in a Diamond Anvil Cell (DAC) under hydrostatic and non-hydrostatic pr...

2008
Yu-Ting Wei Yu-Ming Zheng J. Paul Chen

Excess intake of boron containing water can pose serious problems on human beings. Traditional technologies are limited by insufficient efficiency especially for trace boron removal. In this study, a novel sorbent was developed. A series of batch sorption experiments was conducted to investigate the boron sorption behaviors of the synthesized chitosan based sorbent. Our results show, comparing ...

Journal: :The Journal of nutrition 2003
Naomi A Bakken Curtiss D Hunt

Because dietary boron deprivation induces hyperinsulinemia in vitamin D-deprived rats, the influence of dietary boron on insulin metabolism as modified by nutritional stressors was examined in two animal models. Male weanling Sprague-Dawley rats were assigned to each of four (Experiment 1) or 8 (Experiment 2) dietary groups for 35 d: the basal diet (< 0.2 mg B; <1.0 mg Mg/kg) was supplemented w...

Journal: :Journal of radiation research 2010
Sanath Kumar Svend O Freytag Kenneth N Barton Jay Burmeister Michael C Joiner Bijan Sedghi Benjamin Movsas Peter J Binns Jae Ho Kim Stephen L Brown

Boron Neutron Capture Therapy (BNCT) effectiveness depends on the preferential sequestration of boron in cancer cells relative to normal tissue cells. We present a novel strategy for sequestering boron using an adenovirus expressing the sodium iodide symporter (NIS). Human glioma grown subcutaneously in athymic mice and orthotopic rat brain tumors were transfected with NIS using a direct tumor ...

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