Search results for "Molar"
showing 10 items of 1069 documents
Magnesium chloride modified with organoaluminium compounds as a support of the zirconocene catalyst for ethylene polymerisation
2004
Abstract This work describes the influence of the modification of the MgCl2(THF)2 and MgCl2 magnesium supports with the AlEt2Cl, MAO, AlEt3, AlMe3, and AlEt2Cl alkylaluminium compounds on heterogenisation of the bis(cyclopentadienyl) zirconium(IV) dichloride Cp2ZrCl2 catalyst. It was found that only the MgCl2(THF)2 support modified with AlEt2Cl gave the heterogeneous catalyst. On the contrary, application of a magnesium carrier modified by AlEt3, AlMe3, and MAO compounds only results in a homogeneous zirconocene catalyst.
Heterogeneous zirconocene catalyst on magnesium support MgCl2(THF)2 modified by AlEt2Cl for ethylene polymerisation
2005
Abstract The heterogeneous bis(cyclopentadienyl)zirconium(IV) dichloride catalyst of the composition MgCl2(THF)/(AlEt2Cl)0.34/(Cp2ZrCl2)0.01 as determined by FTIR, XRD, and AAS analyses was synthesised and, after activation by MAO, applied for ethylene polymerisation. The catalyst turned out to be stable and more active than those magnesium supported catalysts already known from the literature. The polyethylene produced has a relatively high molecular weight (Mw > 200,000 g/mol), a narrow and monomodal molecular weight distribution (MWD = 2.4), a bulk density of about 180 g/dm3, and monomodal particle size distribution. Application of a ternary Al(i-Bu)3/MAO/B(C6F5)3 activator decreased the…
A propos de l'observation de cas de campagnols des champs Microtus arvalis (Pallas, 1778) (Rodentia, Arvicolinae) caractérisés par une première molai…
2008
About some cases of common voles Microtus arvalis (Pallas, 1778) (Rodentia, Arvicolinae) characterised by a first lower molar with a pitymyan rhombus. This note describes and comments on some cases of common voles Microtus arvalis (Pallas, 1778) characterised by a first lower molar with a pitymyan rhombus.
Separation of aminoalkanephosphonic acid enantiomers by indirect UV detection capillary electrophoresis with application of cyclodextrins.
2003
Indirect UV detection capillary electrophoresis (CE) was used for the separation of aminoalkanephosphonic acid (AP) enantiomers by applying commercially available cyclodextrins as chiral discriminators. The results show that the separation of the enantiomers depends on pH of the background electrolyte, the molar ratio of cyclodextrin to aminophosphonic acid, and on the type of the applied chiral selector. Optimization of process conditions allowed enantiomeric baseline separation or partial separation of 12 out of 14 alpha-aminophosphonic acids studied. This type of CE might therefore be successfully used for routine determination of enantiomeric purity of aminophosphonic acids.
Ethylammonium hydrogen oxalate–oxalic acid (2/1)
2019
The reaction between ethylamine and oxalic acid in water in a 1:1 molar ratio afforded the title salt, C2H8N+·C2HO4 −·0.5C2H2O4. The hydrogen oxalate anions interact through hydrogen bonding and are organized into a chains propagating along the c-axis direction. The chains are connected to the neighbouring cations and oxalic acid molecules by N—H...O and O—H...O hydrogen bonds and N...O dipole–dipole contacts, leading to a supramolecular three-dimensional network.
Temperature effect on solubility of aroma compounds in various aqueous solutions
2005
International audience; Solubility of nine aroma compounds (methyl ketones, ethyl esters, aldehyde and alcohol) in various aqueous solutions was measured by the mutual solubility method from -10 to +10degreesC. Influence of both, the nature (carbohydrates and polyols) and the substrate concentration (from 0 to 57.5g/100g) on aroma solubility in aqueous solutions was studied. Aroma solubility in water decreased when aroma hydrophobicity increased. Aroma solubility in various aqueous solutions decreased when substrate concentration increased; their solubility was higher in polyols solutions than in polysaccharides ones. Temperature effect on aroma solubility showed a noncontinuous evolution f…
Vides faktoru ietekme uz asaru osmolaritāti
2018
Maģistra darbs ir uzrakstīts latviešu valodā, datorsalikumā uz 55 lapām. Tas satur 3 tabulas, 40 attēlus un 40 atsauces uz literatūras avotiem. Darba mērķis bija novērtēt vides faktoru ietekmi uz asaru osmolaritāti un acs priekšējo struktūru izmeklējumu rezultātiem, kā arī noskaidrot šo parametru savstarpējo mijiedarbību. Pētījums norisinājās 3 daļās, 1. daļā “Aptaujas daļā” piedalījās 125 dalībnieki, 2. daļā “Izmeklējumu daļā” piedalījās 54 dalībnieki un 3. daļa “Atkārtoto mērījumu daļā” piedalījās 21 dalībnieks. Rezultāti parādīja, ka gaisa relatīvais mitrums atstāj ietekmi uz asaru osmolaritāti. Asaru osmolaritāte korelē ar Širmera testa rezultātiem, radzenes krāsošanos un TBUT laiku. Ti…
Understanding distortions of inorganic substructures in chloridobismuthates(III)
2021
The molar ratio variations of organic and inorganic reactants of chloridobismuthates(III) with N,N-dimethylethane-1,2-diammonium, [(CH3)2NH(CH2)2NH3]2+, and N,N,N′,N′-tetramethylguanidinium, [NH2C{N(CH3)2}2]+, cations lead to the formation of four different products, namely, tris(N,N-dimethylethane-1,2-diammonium) bis[hexachloridobismuthate(III)], [(CH3)2NH(CH2)2NH3]3[BiCl6]2 (1), catena-poly[N,N-dimethylethane-1,2-diammonium [[tetrachloridobismuthate(III)]-μ-chlorido]], {[(CH3)2NH(CH2)2NH3][BiCl5]} n (2), tris(N,N,N′,N′-tetramethylguanidinium) tri-μ-chlorido-bis[trichloridobismuthate(III)], [NH2C{N(CH3)2}2]3[Bi2Cl9] (3), and catena-poly[N,N,N′,N′-tetramethylguanidinium [[dichloridobismutha…
Endodontic management of single rooted immature mandibular second molar with single canal using MTA and platelet-rich fibrin membrane barrier: A case…
2011
An immature tooth with pulpal necrosis and periapical pathology imposes a great difficulty to the endodontists. Endodontic treatment options for such teeth consist of conventional apexification procedure with and without apical barriers. Various materials have been tried as apical matrix in the past. This article demonstrates the newer concept of using platelet rich fibrin membrane as an apical matrix barrier for stabilization of MTA in root end apexification procedure. Platelet Rich Fibrin is an autologous fibrin matrix containing a large quantity of platelet and leukocyte cytokines, which enhance healing by release of growth factors. This case report represents successful management of a …
Peripheral ameloblastoma: A case report
2020
Background Ameloblastoma is a rare tumor which develops from odontogenic epithelium and its remnants and it occurs in the jaws. Peripheral ameloblastomas are rare and benign extraooseous ameloblastomas which effects soft tissues. This case report declares a peripheral ameloblastoma which is a rare type of ameloblastoma. Material and methods 34 year old female patient referred with a complaint of a gingival growth at right lower premolar area. A firm and granular surfaced gingival growth with the color of pink and red and having 1.5x1 cm sizes was observed at the mentioned area. With an incision from lower right second incisor tooth to lower right second molar tooth a flap from bone was made…