نتایج جستجو برای: boron

تعداد نتایج: 18025  

Journal: :Plant physiology 1977
M S Cohen

This work establishes that cessation of root elongation of intact squash (Cucurbita pepo L.) plants is an early result of boron deficiency. Root elongation is slowed by 6 hours and is virtually stopped as early as 24 hours after boron is first withheld from the nutrient solution. As root elongation ceased, cell elongation progressed distally into the region normally occupied by the apical meris...

Journal: :Saudi medical journal 2012
Huseyin Per Mehmet Canpolat Ugur Sahin Hakan Gumus Bahadir Konuskan Sefer Kumandas

OBJECTIVE To determine the role of serum and urine selenium, and boron levels in children with resistant epilepsy. METHODS Serum and urine boron and selenium levels were studied in 53 cases (32 boys and 21 girls) diagnosed with resistant epilepsy between April 2006 and February 2007 at the Department of Pediatric Neurology, Erciyes University, Kayseri, Turkey. Differences between groups were...

2004
T. Sourmail T. Okuda J. E. Taylor

The beneficial effect of boron on the mechanical properties of austenitic stainless steels is well documented [1, 2]. A number of studies have confirmed that boron segregates to grain boundaries, in a variety of steels and nickel-base alloys (for example, [3, 4, 5]). Segregation of boron is known to occur via two mechanisms (for example, [1]): Equilibrium segregation is caused by the high bindi...

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...

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