نتایج جستجو برای: nitrogen rich compounds
تعداد نتایج: 486731 فیلتر نتایج به سال:
Nitrides, carbides, and borides of transition metals are an attractive class of hard materials. Our recent preliminary explorations of the binary chemical compounds indicated that chromium-based materials are among the hardest transition metal compounds. Motivated by this, here we explore in detail the binary Cr-B, Cr-C, and Cr-N systems using global optimization techniques. Calculated enthalpy...
Using a simple copper catalyst, the alkylation of nitroalkanes with α-bromocarbonyls is now possible. This method provides a general, functional group tolerant route to β-nitrocarbonyl compounds, including nitro amides, esters, ketones, and aldehydes. The highly sterically dense, functional group rich products from these reactions can be readily elaborated into a range of complex nitrogen-conta...
The Cenomanian-Turonian Gharesu section in the east of Kopet-Dagh basin have been investigated to determine the relationship between palaeoenvironmental perturbations and nitrogen cycling across OAE2. This succession is composed of 43 m shale and marl interbedded with glauconitic sandstone and lies between Aitamir-Abderaz formations boundary. The nitrogen Isotope values fluctuate between 0‰ to ...
Abstract: Energetic salts as a unique class of energetic materials have recently been investigated widely, since they possess advantages over their atomically similar nonionic analogues – they tend to exhibit lower vapor pressures, higher densities and better thermal stabilities. Furthermore, these salts are readily improved upon by the appropriate combination of different cations and anions. O...
The synthesis of bis(formazanate) zinc complexes is described. These complexes have well-behaved redox-chemistry, with the ligands functioning as a reversible electron reservoir. This allows the synthesis of bis(formazanate) zinc compounds in three redox states in which the formazanate ligands are reduced to "metallaverdazyl" radicals. The stability of these ligand-based radicals is a result of...
INTRODUCTION Industrial nitrogen fixation plays an important role in sustaining approximately 40% of the Earth’s population through generation of synthetic fertilizers. Annually, ca. 500 million tons of anhydrous ammonia, ammonium nitrate, and urea are produced through the Haber-Bosch process, which requires harsh conditions (200 atm, 450-500C) and affords low yields 10-20%. It has been estimat...
Organics found in comet 81P/Wild 2 samples show a heterogeneous and unequilibrated distribution in abundance and composition. Some organics are similar, but not identical, to those in interplanetary dust particles and carbonaceous meteorites. A class of aromatic-poor organic material is also present. The organics are rich in oxygen and nitrogen compared with meteoritic organics. Aromatic compou...
Reducing the use of pesticides represents a major challenge of modern agriculture. Plants synthesize secondary metabolites such as polyphenols that participate in the resistance to parasites. The aim of this study was to test: (1) the impact of nitrogen deficiency on tomato (Solanum lycopersicum) leaf composition and more particularly on two phenolic molecules (chlorogenic acid and rutin) as we...
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