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71.
The Fourier transform infrared (FTIR) spectral analysis has been carried out for sediments of Vellar river, Tamilnadu collected
at various depths from twenty seven different locations. The minerals such as quartz, feldspar (microcline and orthoclase),
kaolinite, palygorskite, calcite, aragonite, montmorillonite, cerussite, hematite, sepiolite, magnesium oxalate and organic
carbon are identified. Among these, quartz, feldspar and kaolinite are the major minerals and palygorskite, calcite, aragonite,
montmorillonite, cerussite, hematite, sepiolite, magnesium oxalate and organic carbon are minor and traces. The relative distribution
of these three major minerals was determined by computing the extinction co-efficient. The crystalline nature of quartz is
judged by calculating crystallinity index which shows that the crystalline nature decreases with increase of depth. The observation
made through relative distribution, shows that the amount of quartz and feldspar are relatively reduced and that of kaolinite
is increased from upper to inner depth. As the depth increases the bands of kaolinite progressively broaden and shift to higher
wave number side which suggests that the content of kaolinite increases with disorderedness. From XRD analysis, the minerals
such as monazite, zircon and kyanite are additionally identified. The crystalline nature of quartz is also confirmed. 相似文献
72.
The preferred conformations of N-nitroso-t(3)-alkyl-r(2),c(6)-bis(2′-furyl)-piperidin-4-ones 1–3 [alkyl = CH3, C2H5 and CH(CH3)2] and N-nitroso-t(3),t(5)-dimethyl-r(2),c(6)-bis(2′-furyl)piperidin-4-one 4 in solutions were assigned by means of 1H and 13C NMR studies. The results derived from NMR spectra indicate the presence of an equilibrium mixture of boat conformation B
1
and alternate chair conformation CA for the E isomers of 1–3 and Z isomers of 2–3. For the Z isomer of 1 boat form B
2
is predicted to be the major conformer. The N-nitroso-3,5-dimethyl derivative 4 exists in the boat form B
1
only. Conformational analysis performed through semiempirical molecular orbital calculations also supports the conformations
for 3–4. The presence of one conformer in the equilibrium can be predicted to a reasonable accuracy by theoretical studies in 1–2. The effects due to N-nitrosation on 1H and 13C chemical shifts are also interpreted in terms of these conformations. The conformation of isopropyl group at C(3) was also
predicted by spectral and theoretical studies. 相似文献
73.
Garima Agarwal Vaibhav Kulshrestha Rajkumar Jain D. Kabiraj Indra Sulania Pawan Kulriya I. P. Jain 《Surface and interface analysis : SIA》2009,41(9):746-752
Swift heavy ion (SHI) induced modification at metal/Si interfaces has emerged as an interesting field of research due to its large applications. In this study, we investigate SHI‐induced mixed molybdenum silicide film with ion fluences. The molybdenum thin films were deposited on silicon substrates using e‐beam evaporation at 10?8 torr vacuum. Thin films were irradiated with Au ions of energy 120 MeV to form molybdenum silicide. The samples were characterized by grazing incidence X‐ray diffraction (GIXRD) technique for the identification of phase formation at the interface. Rutherford backscattering spectrometry (RBS) was used to investigate the elemental distribution in the films. The mixing rate calculations were made and the diffusivity values obtained lead to a transient melt phase formation at the interface according to thermal spike model. Irradiation‐induced effects at surface have been observed and roughness variations at the surface were calculated using atomic force microscopy (AFM) technique. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
74.
Size effect of silver nano particles on the photophysical properties of 1,4-dihydroxy-2,3-dimethyl-9,10-anthraquinone (DHDMAQ)
have been investigated using optical absorption and fluorescence emission techniques. Silver nanoparticles of different sizes
have been prepared by Creighton method using magnetic stirrer and ultrasonic field. Quenching of fluorescence of DHDMAQ has
been found to increase with decrease in the size of the silver nanoparticles. Stern–Volmer quenching constants have also been
calculated. 相似文献
75.
Diversity in Gold‐Catalyzed Formal Cycloadditions of Ynamides with Azidoalkenes or 2H‐Azirines: [3+2] versus [4+3] Cycloadditions 下载免费PDF全文
Samir Kundlik Pawar Rajkumar Lalji Sahani Prof. Dr. Rai‐Shung Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(30):10843-10850
Gold‐catalyzed cycloadditions of ynamides with azidoalkenes or 2H‐azirines give [3+2] or [4+3] formal cycloadducts of three classes. Cycloadditions of ynamides with 2H‐azirine species afford pyrrole products with two regioselectivities when the Cβ‐substituted 2H‐azirine is replaced from an alkyl (or hydrogen) with an ester group. For ynamides substituted with an electron‐rich phenyl group, their reactions with azidoalkenes proceed through novel [4+3] cycloadditions to deliver 1H‐benzo[d]azepine products instead. 相似文献
76.
Foldamers to Nanotubes: Influence of Amino Acid Side Chains in the Hierarchical Assembly of α,γ4‐Hybrid Peptide Helices 下载免费PDF全文
Dr. Sandip V. Jadhav Rajkumar Misra Dr. Hosahudya N. Gopi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(50):16523-16528
Supramolecular assembly of various artificially folded 12‐helical architectures composed of γ4‐Val, γ4‐Leu and γ4‐Phe residues is investigated. In contrast to the 12‐helices composed of γ4‐Val and γ4‐Leu residues, the helices with γ4‐Phe residues displayed unique elongated nanotubular architectures. The elongated nanotube assembly was further explored as a template for biomineralization of silver ions to silver nanowires. A comparative study using an analogous α‐peptide helix reveals the importance of the spatial arrangement of aromatic side chains along the helical cylinder in a 12‐helix. These results suggested that the proteolytically and structurally stable α,γ4‐hybrid peptide 12‐helices may serve as a new generation of potential templates in the design of functional biomaterials. 相似文献
77.
Thangamani Rajesh Yong Hyun Kim Yong-Keun Choi Jong Min Jeon Hyun Joong Kim Sung-Hee Park Hyung-Yeon Park Kwon-Young Choi Hyungsup Kim Hyung Joo Kim Sang Hyun Lee Yung-Hun Yang 《Applied biochemistry and biotechnology》2013,170(2):359-369
Amylases are important industrial enzymes that have been applied widely in the food, detergent, and pulp industries and fermentation processes. In the present study, a gene encoding an alpha-amylase from the genomic DNA library of Paenibacillus sp. was identified and characterized. The amylase gene designated amy1 was shown to consist of 1,980 bp and shared sequence identity towards α-amylase genes from other Bacillus sp. The deduced amino acid sequence for Amy1 indicated 80 % sequence identity with other Bacillus strains. Heterologous expression of recombinant Amy1 in Escherichia coli BL21(DE3) facilitated the recovery of this protein in soluble form. Enzyme kinetic data revealed Amy1 to have a K m of 23.83 mg/mL and K cat of 48.74 min?1 and K cat /K m of 2 min?1 mg?1 mL?1 for starch. The activity of this protein was found to be enhanced by Mn2+, and furthermore, Amy1 remained active at a broad pH range (4–10) and temperature (30–90 °C). The ability of Amy1 to act on food waste under broad temperature and pH conditions, together with its ability to produce simple sugars, shows many advantages for further application in the food industry. 相似文献
78.
79.
Fabrication of Nickel Tetrasulfonated Phthalocyanine Functionalized Multiwalled Carbon Nanotubes on Activated Glassy Carbon Electrode for the Detection of Dopamine 下载免费PDF全文
Chelladurai Karuppiah Rajkumar Devasenathipathy Shen‐Ming Chen Danial Arulraj Selvakumar Palanisamy Veerappan Mani V. S. Vasantha 《Electroanalysis》2015,27(2):485-493
The nickel tetrasulfonated phthalocyanine (NiTsPc) functionalized multiwalled carbon nanotube (MWCNT) nanocomposite was prepared by a simple sonochemical method. Here, NiTsPc served as a dispersing agent for MWCNT via π? π interaction between MWCNT and NiTsPc. The activated glassy carbon electrode (AGCE) modified with MWCNT‐NiTsPc composite exhibited a good electrocatalytic ability toward dopamine and displayed a good linear dependence in the concentration range of 20 nM–1.384 mM with a sensitivity of 0.17 µA µM?1 cm?2. The detection limit is 1 nM based on the signal‐to‐noise ratio of 3. 相似文献
80.
Electrochemical Activation of Graphite Nanosheets Decorated with Palladium Nanoparticles for High Performance Amperometric Hydrazine Sensor 下载免费PDF全文
Chelladurai Karuppiah Murugan Velmurugan Shen‐Ming Chen Rajkumar Devasenathipathy Raj Karthik Sea‐Fue Wang 《Electroanalysis》2016,28(4):808-816
Herein, we have demonstrated a preparation of palladium nanoparticles on electroactivated graphite nanosheets modified screen printed carbon electrode (PdNPs‐EGNS/SPCE) by a simple electrochemical method. The well‐prepared electrocatalyst was potentially applied to the high performance electrocatalytic oxidation of hydrazine in neutral medium. The PdNPs‐EGNS novel composite was characterized by scanning electron microscope (SEM) and the average diameter and thickness of PdNPs and EGNS were found to be ~38 nm and 85 nm, respectively. The high performance electrocatalytic determination of hydrazine was performed by the amperometric i‐t method. The fabricated sensor displayed irreversible electrocatalytic oxidation of hydrazine with diffusion‐controlled electrode process. The oxidation of hydrazine at PdNPs‐EGNS/SPCE showed wider linear range 0.05–1415 µM and high sensitivity 4.382 µA µM?1 cm?2. The as‐prepared electrocatalyst achieved quick response towards hydrazine with a lower detection limit 4 nM. 相似文献