نتایج جستجو برای: boron compounds
تعداد نتایج: 243622 فیلتر نتایج به سال:
The B(a; n)N reaction is studied as an activation process in a variety of solid boron-containing neutron shielding materials. The source of a-particles is the neutron capture reaction B(n; a)Li. Samples of boron carbide, boron oxide, and boron nitride are irradiated with thermal neutrons and the rate of N production is determined. N promptly decays, emitting a positron. This positron efficientl...
We have calculated the thermal conductivities (κ) of cubic III-V boron compounds using a predictive first principles approach. Boron arsenide is found to have a remarkable room temperature κ over 2000 W m(-1) K(-1); this is comparable to those in diamond and graphite, which are the highest bulk values known. We trace this behavior in boron arsenide to an interplay of certain basic vibrational p...
25 Laurentia Gales 258 Șos.Fundeni, 2nd District, Bucharest, Romania e-mail: [email protected] Abstract. Boron neutron capture theory (BNCT) is a binary therapy applied in malignant tumours, resistant to other treatment methods, namely chemotherapy and radiotherapy. One of the main components is Bor-10, a stable isotope that can be inserted in the tumour cells by using specific transpor...
Managing urban pests with “environmentally-friendly” compounds has gained importance in recent years with the global deregistration of persistent organochlorine insecticides. Boron compounds, especially boric acid, zinc borate, and disodium octaborate tetrahydrate, are considered excellent options for preserving lumber from insect attack as well as decay by fungi and bacteria. Remedial borate a...
The chemical reactivity of atomic boron, B(Pj), with inorganic and organic molecules is a fascinating subject of research from the experimental1-35 and theoretical viewpoints.29,30,36-46 Atomic boron resides in the same row as carbon, nitrogen, and oxygen.47 Although the reaction dynamics and kinetics of the latter elements (C, N, O) have been studied in depth,48-53 an investigation of elementa...
Boron is a unique element in terms of electron deficiency and Lewis acidity. Incorporation of boron atoms into an aromatic carbon framework offers a wide variety of functionality. However, the intrinsic instability of organoboron compounds against moisture and oxygen has delayed the development. Here, we present boron-doped graphene nanoribbons (B-GNRs) of widths of N=7, 14 and 21 by on-surface...
The concentration of boron, an essential micronutrient for plants, presents a narrow range between deficiency and toxicity. In order to provide the boron requirement for plants, and to avoid toxicity problems, boron compounds are mixed with basic fertilizers. Sodium borate pentahydrate was used as a boron source. Ammonium orthophosphates fertilizers with boron were prepared by neutralizing phos...
For over twenty years boron has been of interest to investigators confirming the safety and essentiality of the element in humans. Fruits, vegetables, nuts, and pulses are natural sources of boron in the diet which world wide averages about 1-3 mg daily for most adults. In boron-rich regions of Turkey drinking water sources with 29 mg boron/liter are consumed without harmful effects. The Europe...
Boronyl (BO) is a monovalent σ radical with a robust B≡O triple bond. Although BO/BO(-) are isovalent to CN/CN(-) and CO, the chemistry of boronyl has remained relatively unknown until recently, whereas CN/CN(-) and CO are well-known inorganic ligands. Further analogy may be established for BO versus H or Au ligands, which are all monovalent σ radicals. This Account intends to provide an overvi...
In this report, a Passerini three-component reaction utilizing boron-containing carboxylic acids or aldehydes is discussed. The reaction was carried out in water and facilitated by the use of microwave irradiation. This methodology allowed for the efficient formation of a broad range of boron-containing α-acyloxyamides under mild conditions within a short time. Two series of boron-containing α-...
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