نتایج جستجو برای: phosphoric acids
تعداد نتایج: 283841 فیلتر نتایج به سال:
به روش zro2 -tio در این پایان نامه سنتز مخلوط اکسیدهای فلزی 2 با استفاده از سورفاکتانت مورد بررسی zr/ti= سل- ژن و با نسبت مولی 1 قرار گرفت. ساختار ترکیب حاصل کاملا آمورف بوده و نسبت به مخلوط اکسیدهای فلزی تهیه شده به روش همرسوبی خواص کاتالیزوری بهتری از خود نشان داد . استفاده از سورفاکتانت باعث افزایش مساحت سطح و بهبود خواص کاتالیزوری این مخلوط اکسید فلزی شد. این ترکیب توسط درصدها وزنی مخت لفی ...
Reverse phase high pressure liquid chromatography (HPLC) on octadecylsilyl columns separates mixtures of either free fatty acids or fatty acid methyl esters prepared from mammalian tissue phospholipids. Acetonitrile-water mixtures are used for the elution of esters. Aqueous phosphoric acid is substituted for water for the separation of the free acids. Unsaturated compounds are detected and quan...
a study was carried out to investigate the effects of organic acid mixture as well as two methionine supplements on performance, carcass characteristics and weight of gastrointestinal tract in broiler chickens. six hundred unsexed day-old ross 308 broiler chicks were utilized in a factorial arrangement of treatments (3×2) based on completely randomized design (crd) of 4 replicates of 25 chicks ...
root resorption (rr) is defined as the loss of dental hard tissues because of clastic activity inside or outside of tooth the root. in the permanent dentition, rr is a pathologic event; if untreated, it might result in the premature loss of the affected tooth. several hypotheses have been suggested as the mechanisms of root resorption such as absence of the remnants of hertwig's epithelial root...
Oyster shells have received attention for use as a calcium resource. For this study, calcium phosphate was prepared from phosphoric acid and oyster shells. The influences of the concentration of phosphoric acid and pH in the preparation conditions were studied from the yields of calcium phosphate and unreacted carbonate, and the Ca/P ratios in precipitates. The yield of calcium phosphate and ca...
A most effective and less energy demanding method of producing fatty esters, diol esters, by esterifying fatty acids, with neopentyl and ethylenglycol alcohols in the presence of an acidic ion exchange resin catalyst(polyestyrendivinylbenzensulfated) was investigated at elevated temperature. In this process an azeotroping agent, toluene, was used to facilitate continuous removal of water by dis...
OBJECTIVE Although self-etching bonding systems (SES) are indicated to prepare dental enamel for bonding, concerns have been expressed regarding their effectiveness. The aim of this study was to analyze the etching pattern (EP) of nine SES in comparison with 35% and 34% phosphoric acid etchants (FA) on intact (IN) and ground (GR) enamel surface. MATERIALS AND METHODS Twenty-two human third mo...
The purpose of the present study was to assess the bond strength of composite resin repairs subjected to different surface treatments and accelerated artificial aging. 192 cylindrical samples (CSs) were prepared and divided into 24 groups (n = 8). Half of the CSs were stored in water for 24 h, and the other half were subjected to C-UV accelerated aging for non-metallic specimens. The treatments...
At present, leucine-induced hypoglycemia and maple-syrup urine disease are the only inborn errors of leucine metabolism recognized in man. In the former disorder, recurrent hypoglycemia is the result of leucine-induced hyperinsulinism.1 In maple-syrup urine disease there is a block in the oxidative decarboxylation of leucine, isoleucine, and valine resulting in the accumulation of the amino aci...
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