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81.
Rajesh K Vatsa Chiranjib Majumder Onnattu D Jayakumar Shailendra K Kulshreshtha Jai P Mittal 《Journal of Chemical Sciences》2001,113(2):129-138
Multiphoton dissociation/ionization has been studied for CH3SCH3 at 355 and 532 nm using a time-of-flight mass spectrometer. The major ion signals observed at 355 nm are C+, CH3
+, HCS+, CH2S+, CH3S+ and CH3SCH3
+. Power dependence studies at 355 nm show a (2+1) REMPI process for the formation of parent ion. Peaks atm/e = 46, 47 and 61 show two-photon laser power dependence whereasm/e = 15 and 45 peaks show four-photon dependence. However, in 532 nm photo-ionisation, no parent ion signal is observed. A peak
atm/e = 35 corresponding to SH3
+ has been observed. SH3
+ has been suggested to originate from CH3SCH2
+ via a cyclic transition state. Photoionisation results of CH3SCH3 have been compared with those of CH3SSCH3, at these two wavelengths. 相似文献
82.
B.B. Lahiri S. Bagavathiappan T. Jayakumar John Philip 《Infrared Physics & Technology》2012,55(4):221-235
Abnormal body temperature is a natural indicator of illness. Infrared thermography (IRT) is a fast, passive, non-contact and non-invasive alternative to conventional clinical thermometers for monitoring body temperature. Besides, IRT can also map body surface temperature remotely. Last five decades witnessed a steady increase in the utility of thermal imaging cameras to obtain correlations between the thermal physiology and skin temperature. IRT has been successfully used in diagnosis of breast cancer, diabetes neuropathy and peripheral vascular disorders. It has also been used to detect problems associated with gynecology, kidney transplantation, dermatology, heart, neonatal physiology, fever screening and brain imaging. With the advent of modern infrared cameras, data acquisition and processing techniques, it is now possible to have real time high resolution thermographic images, which is likely to surge further research in this field. The present efforts are focused on automatic analysis of temperature distribution of regions of interest and their statistical analysis for detection of abnormalities. This critical review focuses on advances in the area of medical IRT. The basics of IRT, essential theoretical background, the procedures adopted for various measurements and applications of IRT in various medical fields are discussed in this review. Besides background information is provided for beginners for better understanding of the subject. 相似文献
83.
R. Mittal S. L. Chaplot A. I. Kolesnikov C. -K. Loong O. D. Jayakumar S. K. Kulshreshtha 《Pramana》2004,63(2):405-408
We report here measurements of phonon spectrum and lattice dynamical calculations for GaPO4. The measurements in low-cristobalite phase of GaPO4 are carried out using high-resolution medium-energy chopper spectrometer at ANL, USA in the energy transfer range 0–160 meV.
Semiempirical interatomic potential in GaPO4, previously determined using ab-initio calculations have been widely used in studying the phase transitions among various
polymorphs. The calculated phonon spectrum using the available potential show fair agreement with the experimental data. However,
the agreement between the two is improved by including the polarisability of the oxygen atoms in the framework of the shell
model. The lattice dynamical models are also exploited for calculations of various thermodynamic properties of GaPO4. 相似文献
84.
Dr. Jayachandran Jayakumar Guganchandar Vedarethinam Huan-Chang Hsiao Shang-You Sun Prof. Dr. Shih-Ching Chuang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(2):699-704
Quaternary ammonium salts were synthesized in moderate to good yields through double oxidative C−H bond activation on azobenzenes. The mechanism of the highly regioselective reaction of 2-azobiaryls with alkenes to give orange-red-fluorescent cinnolino[2,3-f]phenanthridin-9-ium salts and 15H-cinnolino[2,3-f]phenanthridin-9-ium-10-ide is proposed to involve ortho C−H olefination of the 2-azobiaryl compound with the alkene, intramolecular aza-Michael addition, concerted metalation–deprotonation (CMD), reductive elimination, and oxidation. 相似文献
85.
The dehydration of aldoximes and amides, and oxidation of benzoin are accomplished in one-pot using in situ–generated Burgess-type reagent.
Keywords: Amide, benzil, benzoin, Burgess reagent, Burgess-type reagent, dehydration, nitrile, oxidation, oxime
86.
Ching‐Zong Luo Dr. Parthasarathy Gandeepan Jayachandran Jayakumar Dr. Kanniyappan Parthasarathy Yu‐Wei Chang Prof. Dr. Chien‐Hong Cheng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(42):14181-14186
An efficient and convenient method for the synthesis of highly substituted polycyclic pyridinium salts from the reaction of various 2‐aryl‐pyridines and 2‐aryl‐sp2‐nitrogen‐atom‐containing heterocycles with alkynes through rhodium(III)‐catalyzed C? H activation and annulation under an O2 atmosphere is described. A possible mechanism that involves the chelation‐assisted C? H activation of the 2‐aryl‐pyridine substrate, insertion of the alkyne, and reductive elimination is proposed. This mechanism was supported by the isolation of a five‐membered rhodacycle ( I′ ). In addition, kinetic isotope studies were performed to understand the intimate reaction mechanism. 相似文献
87.
Lakshmi R. Lakshman K. T. Shalumon Sreeja V. Nair R. Jayakumar S. V. Nair 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):1012-1018
Polyurethane foam is currently used as an exudate absorptive wound dressing material. In this study silver (Ag) nanoparticles were incorporated into electrospun polyurethane (PU) nanofiber to enhance the antibacterial as well as wound healing properties. The electrospinning parameters were optimized for PU with and without silver nanoparticles. Silver nanoparticles were synthesized by aqueous and organic methods. The water absorption, antibacterial and cytocompatibility of the PU-Ag nanofibers were studied and compared to that of conventional PU foam. The results indicated that the PU-Ag nanofibers could be used for wound dressing applications. 相似文献
88.
Lakkavarapu Suresh Jayakumar Singh Bondili Pradeep Kumar Brahman 《Electroanalysis》2020,32(7):1439-1448
Present work demonstrates the fabrication of new and facile sandwich‐type electrochemical immunosensor based on palladium nanoparticles (PdNPs), polyaniline (PANI) and fullerene‐C60 nanocomposite film modified glassy carbon electrode (PdNP@PANI‐C60/GCE) for ultrasensitive detection of Prostate‐specific antigen (PSA) biomarker. PdNP@PANI‐C60 was electrochemically synthesized on GCE and used as an electroactive substrate. PdNP@PANI‐C60 was characterized by scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDS), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Primary antibody anti‐PSA (Ab1) was covalently immobilized on PdNP@PANI‐C60/GCE using NHS/EDC linkers. In the presence of PSA antigen, horseradish peroxidase secondary antibody (HRP‐Ab2) was brought into the surface of the electrode, developing stable amplified signals of H2O2 reduction. Under the optimal conditions, a linear curve for determination of PSA at the proposed immunosensor was 1.6×10?4 ng.mL?1 to 38 ng.mL?1 with a limit of detection (LOD) of 1.95×10?5 ng.mL?1. The proposed immunosensor was successfully validated in serum and urine samples towards PSA detection with satisfactory and acceptable results. 相似文献
89.
K. Jayakumar 《Mathematical and Computer Modelling》2003,37(12-13):1427-1434
First-order autoregressive Mittag-Leffler process is studied. Methods for generating dependent (first-order autoregressive Markovian) sequences of random variables with Mittag-Leffier marginal distributions are discussed. Comparison of the first-order autoregressive Mittag-Leffler process with the first-order autoregressive exponential process of Gaver and Lewis [1] is done. As an application, the first-order autoregressive Mittag-Leffier process is fitted to weakly stream flows of the Kallada River in Kerala, India. 相似文献
90.
Nguyen CT Hoang PH Perumal J Kim DP 《Chemical communications (Cambridge, England)》2011,47(12):3484-3486
A high resolution negative-tone-type of inorganic-organic diblock copolymer photoresist was synthesized as a novel precursor for simple and direct fabrication of SiCN ceramic mesoporous patterns with ordered nanoscale pores by using a "top-down" photolithographic technique and the subsequent sacrificial processes of a "bottom-up" self-assembled nanostructure. 相似文献