نتایج جستجو برای: element boron
تعداد نتایج: 221337 فیلتر نتایج به سال:
Boron is known as a high energy density material. This element is an important fuel for propellants and explosives. Of all the chemical elements, boron has the highest volumetric heat of combustion (140 kJ cm-3) and the third highest gravimetric heat of combustion (59 kJ g-1), after H2 and Be. Furthermore, mentioned element is used for the preparation of many alloy compounds. Therefore, study o...
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...
Boron has a unique chemistry, responsible for remarkable complexities even in the pure element. I review some of the history of the discovery of this element, and recent surprises found in boron under pressure. I discuss the recent discovery of a new high-pressure phase, γ-B28, consisting of icosahedral B12 clusters and B2 pairs in a NaCl-type arrangement: (B2)(B12), and displaying a significan...
In this paper by using DC arc discharge method and acetylene gas, as the carbon source, and nitrogen, as the carrier gas, canrbon nanotubes, CNTs, doped with trivalent element boron, B, have been produced. The deposited CNTs on the cathod electrod, which have structural doped properties to boron element, have been collected and after purification have been investigated by back-scattering Raman...
Boron is a micronutrient in plants and animals, but its specific roles in cellular processes are not known. To understand boron transport and functions, we screened a yeast genomic DNA library for genes that confer resistance to the element in Saccharomyces cerevisiae. Thirty boron-resistant transformants were isolated, and they all contained the ATR1 (YML116w) gene. Atr1 is a multidrug resista...
The elements carbon and boron uniquely form extensive series of compounds with hydrogen; hydrocarbons and boron hydrides. In comparison to carbon, which forms various chainor ring-like structures, boron, an electron deficient element, forms quasi-aromatic clusters architecturally derivable from a twelve-vertex icosahedral unit. Herein, we focus on a comparison of hydrocarbon and boron hydride b...
This review summarizes the evidence for boron essentiality across the biological spectrum with special focus on biochemical pathways and biomolecules relevant to immune function. Boron is an essential trace element for at least some organisms in each of the phylogenetic kingdoms Eubacteria, Stramenopila (brown algae and diatoms), Viridiplantae (green algae and familiar green plants), Fungi, and...
In the seawater desalination field, WHO requires the boron concentration in drinking water to be below 0.5 mg/l, and this requirement has affected SWRO process design, because of the difficulty to achieve such low boron concentration. In order to overcome this problem, a new SWRO membrane element, which had higher boron rejecting performance, was developed. This new SWRO membrane element exhibi...
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