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1.
Because Nitrosomonas europaea contains ammonia-oxidizing enzyme, nitrite reductase, and nitrous oxide reductase, the conversion of ammonia to dinitrogen
was tried with different reaction conditions. In aerobic reaction conditions, ammonium was converted to nitrite (NO
2
−
), while under oxygen-limiting or oxygen-free conditions, NO
2
−
-N formed from ammonia oxidation by N. europaea was reduced to N2O and dinitrogen with 22% conversion. During denitrification, optimal pH for the production of N2O and dinitrogen was found to be 7.0–8.0. Dinitrogen was not produced in acidic pH<7.0. A low partial oxygen pressure as well
as oxygen-free conditions are favorable for high production of dinitrogen. 相似文献
2.
S. P. Hasilkar Keshav Chander S. G. Marathe 《Journal of Radioanalytical and Nuclear Chemistry》1990,139(2):263-271
Attempts to carry out potentiometric determination of plutonium (by AgO-oxidation method) following the determination of thorium (by complexometric EDTA titration) gave positively biased irreproducible values of plutonium. In order to understand the factors leading to the erroneous values of plutonium, the effect of varying amounts of AgO and EDTA on redox [Fe(II)/K2Cr2O7] titration in the medium consisting of 1M H2SO4 and 0,4M HNO3 was studied. When AgO (up to 200 mg) was added in the titration medium and destroyed by sulfamic acid prior to the redox titration, the dichromate tittre value (amount of standard K2Cr2O7 solution equivalent to 1 g of Fe(II) solution) showed negative bias. The bias was found to decrease with increase in time interval between AgO destruction and the redox titration. The presence of EDTA (up to 15 mg) gave positive bias in the titre value. Results on the titre values obtained under different conditions of the aqueous medium indicated the possibility of formation of unstable Ag(II)-sulfamic acid compled, which is probably responsible for the irreproducible values of plutonium. 相似文献
3.
Keshav Chander S. P. Hasilkar S. G. Marathe 《Journal of Radioanalytical and Nuclear Chemistry》1991,154(4):277-284
A method for the sequential determination of thorium and plutonium has been developed. In the sample solution containing thorium and plutonium, thorium is first determined by complexometric titration with EDTA and then in the same solution plutonium is determined by redox titration employing potentiometry. Prior to the determination of plutonium, EDTA is destroyed by fuming with concentrated HClO4. Thorium is determined at 10 mg level and plutonium at 1 mg level with precision and accuracy of better than ±0.5%. 相似文献
4.
S. P. Hasilkar N. Gopinath Keshav Chander S. G. Marathe H. C. Jain 《Journal of Radioanalytical and Nuclear Chemistry》1988,122(1):69-73
A method based on the complexometric titration of thorium using ethylene diaminetetra-acetic acid (EDTA) as complexant has been developed for the determination of thorium in thorium-plutonium solution without resorting to prior separation of plutonium. Plutonium in the form of Pu(VI) does not affect the thorium determination when present up to 10% in thorium—plutonium solution. For oxidation of plutonium to Pu(VI), HClO4 or AgO was used. HClO4 is preferred. The thorium values obtained without prior separation of plutonium are compared with those obtained after separating plutonium by anion exchange technique. A precision of ±0.5% has been obtained for 5–10 mg of thorium in the aliquot. 相似文献
5.
Keshav Chander S. P. Hasilkar A. V. Jadhav H. C. Jain 《Journal of Radioanalytical and Nuclear Chemistry》1993,174(1):127-132
A method for the sequential determination of thorium and uranium has been developed. In the sample solution containing thorium and uranium, thorium is first determined by complexometric titration with ethylenediaminetetraacetic acid (EDTA) and then in the same solution uranium is determined by redox titration employing potentiometry. As EDTA interferes in uranium determination giving positive bias, it is destroyed by fuming with HClO4 prior to the determination of uranium. A precision and accuracy of better than ±0.15% is obtained for thorium at 10mg level and uranium ranging from 5 mg to 20 mg in the aliquot. 相似文献
6.
In the present paper, self-focusing phenomenon occurring as a result of non-linear interaction of intense laser beam with thermal conduction-loss predominant plasmas is studied by following both approaches viz. paraxial theory approach and moment theory approach. Non-linear differential equations for the beam width parameters of laser beam have been set up and solved numerically in both cases to study the variation of beam width parameters with normalized distance of propagation. Effects of laser intensity as well as plasma density on the beam width parameters have also been analyzed. It is observed from the analysis that in case of moment theory approach, strong self-focusing of laser beam is observed as compared to paraxial theory approach. 相似文献
7.
3,3′‐(Sulfonyldi‐1,4‐phenylene)bis(4‐substituted aminosulfonyl)sydnones ( 7a , 7b , 7c , 7d , 7e , 7f , 7g , 7h , 7i , 7j ) were synthesized from the starting material 4,4′‐diaminodiphenylsulfone. The synthesized compounds were characterized by IR, NMR, and elemental analysis. Some of the compounds were effectively active against Gram‐positive bacteria (Streptococcus pneumoniae and Staphylococcus aureus) and Gram‐negative bacteria (Escherichia coli and Pseudomonas aeruginosa). 相似文献
8.
Ornithine methyl ester reacts with aromatic aldehydes to generate bis-Schiff bases, which depending on the structure of the aromatic aldehyde, further undergo an intramolecular cycloaddition through the transient formation of a reactive 1,3-dipole. 相似文献
9.
Lok Kumar Shrestha 《Journal of Dispersion Science and Technology》2013,34(8):1236-1241
We have investigated the phase behavior of diglycerol monomyristate (DGM) in a variety of organic solvents over a wide range of temperatures and compositions. At lower temperature, there exists a surfactant solid, which solubilize different amounts of oils depending on the oil nature. The melting temperature of the solid phase is virtually constant in a wide range of composition. In all the systems, a lamellar liquid crystal (Lα) is formed in surfactant‐rich regions at intermediate temperatures between the solid‐melt and isotropic two‐ or single‐phase regions. In the dilute regions reverse vesicles are formed in the Lα+O regions mainly in the case of linear hydrocarbon type oils. In the aromatic and cyclic aliphatic oils, there are isotropic solutions at 25°C. However, there is dispersion of α‐solid in the case of liner hydrocarbon oils. Two liquid‐phase regions above the Lα phase are observed in the case of tetradecane and hexadecane. In the shorter chain oil systems, such as octane and decane, no two liquid‐phase appear above Lα region. That is the two liquid‐phase region is largely dependent on the chain length of the oils, and becomes wider in longer hydrocarbon oil. 相似文献
10.
An efficient and facile green synthesis of spirooxindole derivatives bearing pyrano[2,3-c]pyrazole moiety has been achieved via a \(\mathrm{CeO}_{2}\)-NPs catalyzed four-component reaction in water. The protocol offers an environmentally benign and effective approach to highly functionalized and biologically interesting spiro[indoline-3,4\(^\prime \)-pyrano[2,3-c]pyrazole] derivatives. The synthesized compounds exhibit potent antioxidant and antibacterial activities. 相似文献