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111.
Anita Raj Sanwaria Nikita Sharma Archana Chaudhary Meena Nagar 《Journal of Sol-Gel Science and Technology》2013,68(2):245-253
Non-aqueous reactions of aluminum isopropoxide with 8-hydroxyquinoline (Hq = HONH6C9) in 1:1, 1:2 and 1:3 molar ratios in anhydrous benzene yield complexes of the type [qnAl(OPri)3?n] {where n = 1 (1), n = 2 (2), n = 3 (3)}. Progress of the reactions were monitored by estimating liberated 2-propanol in benzene-2-propanol azeotrope by oxidimetric method. All the products were fluorescent green powders, sparingly soluble in CHCl3. They were characterized by elemental analysis, FT-IR and (1H, 13C and 27Al) NMR studies. The ESI mass spectral studies indicate dimeric nature for (1) and (2) and monomeric nature for the compound (3). The XRD spectra of (1–3) showed crystalline nature with the average particle size of 45, 32 and 27 nm respectively, as evaluated from Debye–Scherrer equation. The XRD spectrum of (3) also suggests the formation of β-crystalline polymorphs of Alq3. The SEM images appear to indicate granular morphology for (1) and formation of cylindrical shaped rods for (2) and (3). Sol–gel hydrolysis of (1), (2) or (3) in presence of a strong acid as well as of the precursor, Al(OPri)3,without acid or base catalyst, followed by sintering at 950 °C yielded tetragonal primitive phase of nano-sized δ-alumina in all the cases, as reflected by their powder X-ray diffraction pattern. The IR, SEM and EDX studies also support the formation of transition alumina. 相似文献
112.
113.
Vijaya Kabra Sonia Sharma Neelima Gupta Ashok Kumar Priyadarshi Meena 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2212-2219
Novel chiral 1,3,2-oxazaphospholane-2-sulfides incorporating a dihydropyridine ring have been synthesized via phosphorylation of 2-aminopyridinium salts, followed by in situ oxidation and cyclocondensation with 2-(alkylamino)ethanol. Cyclic organothiophosphates thus obtained have been screened for their antioxidant properties. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
114.
Areeba Khayal Virendra Kumar Yadav Shivraj Gangadhar Wanale Krishna Kumar Yadav Abhishek Meena Mohd Shkir Zubair Ahmad Byong-Hun Jeon 《Particle & Particle Systems Characterization》2023,40(8):2300029
Nanotechnology applications are rapidly expanding in various fields because of its unique qualities, such as a large surface area. Also, the synthetic changes can be utilized to alter nanomaterial to fit into specialized necessities. From the last decade there is a tremendous increase in the utilization of nanotechnology and nanomaterials in the petroleum industry. The current review's main objective is to summarize numerous nanoparticle applications in the field of petroleum, bio-fuel formation, and clean-up treatments of oil spill-related issues with their existing challenges that may help improve further research. 相似文献
115.
Hydrogel systems composed of kC/Xylan (kC/OSX or kC/BX) blends and linear polyvinylpyrrolidone (PVP) were prepared in the presence of water soluble initiator sodium persulphate (KPS) with microwave irradiation. The hydrogel materials were investigated by measuring their syneresis, swelling, gel fraction, and rheological properties. Physicochemical and rheological properties of the natural polysaccharide (kC/Xylans) blends were modified significantly after blending with PVP. The introduction of PVP and the formation of semi-interpenetrating polymer network (semi-IPN) structure improved the gelling properties of the resulting hydrogels. It has been proven, that a high incorporation of PVP could only be obtained if the hydrogels were prepared using KPS initiator and microwave irradiation in combination. FTIR, CP-MAS 13C NMR, and elemental analysis confirmed the presence of PVP in the blends but no direct evidence for covalent bonds could be obtained. 相似文献
116.
An efficient regeneration system was established for an ethnomedicinal shrub Rhinacanthus nasutus from root-derived callus organogenesis. The root segments were cultured on MS medium supplemented with various concentrations of Kn (1.0–4.0 μM) alone or in combination with IBA (0.2–0.6 μM) or 2, 4-D (0.5–1.5 μM). The optimum frequency (94 %) of callus induction was recorded on MS medium supplemented with 3.0 μM Kn and 0.4 μM IBA. For shoot regeneration from callus, MS medium supplemented with different concentrations (1.0–7.0 μM) of BA or TDZ alone or in combination with NAA (0.2–1.0 μm) was employed. The highest frequency of shoot regeneration (91 %) and mean number of shoots (28.3) were observed on MS medium supplemented with 5.0 μM BA and 0.7 μM NAA. The shoots were excised and cultured on MS medium with 4.0 μM IBA produced 3.4 roots per shoot in 88 % cultures. Of the 65 plants transferred to soil 54 survived (83 %). The plants were transferred to field after successful hardening. RAPD analysis of the regenerated plants showed high similarity with the mother plant. 相似文献
117.
Fundamental studies on the feasibility of deep eutectic solvents for the selective partition of glaucarubinone present in the roots of Simarouba glauca 下载免费PDF全文
Faisal Kholiya Nidhi Bhatt Meena R. Rathod Ramavatar Meena Kamalesh Prasad 《Journal of separation science》2015,38(18):3170-3175
Several deep eutectic solvents prepared by the complexation of choline chloride as the hydrogen bond acceptor and hydrogen bond donors such as urea, thiourea, ethylene glycol, and glycerol were employed to partition glaucarubinone, an antimalarial compound present in roots of the plant, Simarouba glauca. Among all the solvents, the deep eutectic solvent consisting of the mixture of choline chloride and urea the most suitable to partition the antimalarial compound from the extract selectively. Analytical tools such as high‐performance liquid chromatography and electrospray ionization mass spectrometry were used for characterizations, and glaucarubinone extracted from the roots of the plant by conventional solvent extraction method was used as a reference for comparison. The hydrogen and noncovalent bonds formed between glaucarubinone and the deep eutectic solvents could be responsible for the selective partition of the drug molecule. 相似文献
118.
The boundary value problem in basic enzyme reactions is formulated and approximate expressions for substrate and product concentrations
are presented. He’s variational iteration method is used to give approximate and analytical solutions of non-linear reaction
equations containing a non-linear term related to enzymatic reaction. The relevant analytical solutions for the substrate,
enzyme, substrate-enzyme and product concentration profiles are discussed in terms of dimensionless reaction diffusion parameters
K, λ and e{\varepsilon}. 相似文献
119.
Meena R. Kumar R. P. Dixit 《International Journal of Infrared and Millimeter Waves》2000,21(6):931-938
A broad band VCO has been developed at Ka-band for FMCW Radar applications. To achieve a wide range of frequency variation, VCO has been designed in series configuration. Design steps have been presented. VCO exhibits a tuning range of 600 MHz with the power output of 50 mw, when the controlled varactor voltage varies from 7.5 volts to 15 volts. Frequency drift with temperature has been contained within 30 MHz using a proportionally controlled DC heater module over the temperature range of 0°C to +55°C. Phase Noise of the oscillator measured at the mid and extreme frequencies is about -70 dBc/kHz at 10 kHz away from the carrier. The experimental circuit and measured performance is also presented. 相似文献
120.
Peerzada R. Hussain Raghuveer S. Meena Mohd A. Dar Ali M. Wani 《Radiation Physics and Chemistry》2011,80(7):817-827
The study is aimed at the optimization of gamma irradiation treatment of sun-dried apricots for quality maintenance and quarantine purposes. Sun-dried apricots pre-treated with potassium meta-bisulphite (KMS) at 2.5% w/v were procured from progressive apricot grower of district Kargil, Ladakh region of Jammu and Kashmir state. The sun-dried apricots were packed in 250 gauge polyethylene packs and gamma irradiated in the dose range 1.0–3.0 kGy. The gamma irradiated fruit including control was stored under ambient (15±2–25±2 °C, RH 70–80%) conditions and periodically evaluated for physico-chemical, sensory and microbial quality parameters. Radiation treatment at dose levels of 2.5 and 3.0 kGy proved significantly (p≤0.05) beneficial in retention of higher levels of β-carotene, ascorbic acid, total sugars and color values without impairing the taste as perceived by the sensory panel analysists. The above optimized doses retained the β-carotene content of sun-dried apricots to the extent of 71.2% and 72.6% compared to 63.9% in control samples after 18 months of storage. Irradiation treatment facilitated the release of residual sulfur dioxide in KMS pre-treated sun-dried apricots significantly (p≤0.05) below the prescribed limit for dried products. During storage, two-fold decrease in sulfur dioxide content was recorded in irradiated samples (3.0 kGy) as compared to 16.9% in control. The above optimized doses besides maintaining the higher overall acceptability of sun-dried apricots resulted in 5 log reductions in microbial load just after irradiation and 1.0 and 1.3 log reductions in yeast and mold and bacterial count after 18 months of ambient storage. 相似文献