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161.
Received November 5, 1997 相似文献
162.
The synthesis and cation binding properties of chiral crown ethers derived from 7-deoxycholic acid along with their application in asymmetric Michael reaction are described. 相似文献
163.
Anirudh Pratap Singh Raman Pallavi Jain Ajay Kumar Jaya Tomar Neha Kaushik Eun Ha Choi Nagendra Kumar Kaushik Latifa Negadi Prashant Singh 《印度化学会志》2022,99(8):100570
In this work, DFT calculations for the designed eutectic mixtures (EMs) using oxoazolidine 2,4-dione (OZD) and zinc chloride (ZnCl2) are done. The interaction between the hydrogen bond donor and hydrogen bond acceptor at atomic level to get EMs are studied using DFT calculations. At room temperature, the stability of these various systems have been investigated using thermodynamic values or parameters such as enthalpy, free energy and others. DFT calculations is used to investigate the possibility of forming the systems (EMs). Further, the impact of varying the temperature on each system was also investigated (323K, 348K). Various other thermodynamic parameters are studied like dipole moment, hardness, chemical potential of the systems (individual molecules and EMs) at different temperatures. The results of the calculations showed that O1Z4 and O4Z1 have maximum dipole moment having values 8.1291, 9.8801 respectively, indicating maximum polarizability. Change in free energy for O1Z4 is least and was found to be ?37.2496 kcal/ mol. Further on changing the temperature, the parameters do not show much variation. Additionally, we have analyzed structure activity relationship (SAR) method to understand the physico-chemical properties of designed EMs and predict their regression and correlation to optimized energy. From the calculated values of pOE model, the value of r2 is 0.9995 confirms the validity of the equation obtained. The results of this study suggest a link between the structures that have been utilized to describe the intermolecular interaction between the hydrogen bond donor and acceptor, as well as the stability of the EMs. 相似文献
164.
165.
Nickel-doped anatase TiO2 nanoparticles have been prepared by sol-gel method. The X-ray powder diffraction study reveals that all the prepared samples have pure anatase phase tetragonal system. The average crystallite size of the prepared sample is 14 nm, when found through transmission electron microscope. A strong frequency dependence of both dielectric constant (?′) and dielectric loss (tan δ) were observed for various dopant levels at room temperature in the frequency range of 42 Hz to 5 MHz. At low frequency, the piling up of mobile charge carriers at the grain boundary produces interfacial polarization giving rise to high dielectric constant. The asymmetric shape of frequency dependence of the dielectric loss for the primary relaxation process is observed for each concentration. From the ac conductivity studies, the reduction in conductivity may arise due to the decreasing particle with the increase in Ni-dopant level. 相似文献
166.
An end-to-end assembly of spherical Ag nanoparticles takes place in the presence of biotin to form long fiberlike microstructures. These microstructures are about 4 mum long with a thickness of 1 mum, obtained from SEM studies. TEM studies showed the presence of spherical silver nanoparticles having an average size of 20 nm. ATR-FTIR studies revealed that silver ions interact with biotin involving the carboxylate group. A weak binding of the silver particles with the thioether and ureido groups helps in connecting the Ag nanoparticles to form long fiberlike structures. Elucidation of the mechanism of formation of the spherical Ag clusters was done by pulse radiolysis. 相似文献
167.
Kapoor RN Cervantes-Lee F Campana CF Haltiwanger C Abney K Pannell KH 《Inorganic chemistry》2006,45(5):2203-2208
The reaction between Ta(OEt)5 and 1,1,3,3-tetramethyl-1,3-disiloxanediol, (HOSiMe2OSiMe2OH), leads to new siloxy complexes in which the dimeric nature of Ta(OEt)5 is maintained with both bridging ethoxide and disiloxanediolato bridges. With equal amounts of the reagents, two terminal OEt groups are replaced to form [Ta(OEt)2]2(mu-OEt)2(mu-OSiMe2OSiMe2O)2, 1, whereas with an excess of diol, the remaining terminal OEt groups are also replaced but with a trisiloxanediolato unit to form [Ta(OSiMe2OSiMe2OSiMe2O)]2(mu-OEt)2(mu-OSiMe2OSiMe2O)2, 2. Complexes 1 and 2 catalyze the transformation of HOSiMe2OSiMe2OH to polysiloxanes. Thermal treatment of 1 results in the formation of a 1:2 mixture of Ta2O5/SiO2; no new phases are observed. The molecular structures of 1 and 2 are confirmed by X-ray crystallography. 相似文献
168.
Vijai Singh Pallavi Somvanshi Gaurav Rathore D. Kapoor B. N. Mishra 《Applied biochemistry and biotechnology》2010,160(7):1985-1991
Aerolysin is a significant virulent toxin protein secreted by Aeromonas hydrophila; it produces deep wound infections and hemorrhagic septicemia. The complete aerolysin gene (1,482 bp) was amplified from
A. hydrophila. Furthermore, it was cloned and expressed into Escherichia coli BL21(DE3) codon plus RP cells using 0.5 mM IPTG for induction. The protein size was 54 kDa as estimated by SDS-PAGE, and
it was purified by Ni–NTA affinity chromatography. Anti-His antibodies were used to characterize the expressed aerolysin by
Western blotting and showed hemolytic activity with fish red blood cells. Aerolysin may be used as immunoassays for earlier
control of A. hydrophila and is also compatible for vaccination. 相似文献
169.
A simple derivation, which relates the thermal lens focal length in solid state lasers to pump power and a method for direct
estimation of thermal lens focal length, is reported. This method is applicable to any type of stable resonator. The method
is used for the measurement of the thermal lens focal length with an accuracy of 8% in an axially pumped microchip laser.
The variation of focal length with pump power is also measured. 相似文献
170.
In this work we deal with the dynamical analysis of nonlinear systems with input constraints. A characterization of the domain of attraction of the region of controllability of an equilibrium point under bounded control is provided and the concept of regions of invariance within such domains of attraction is introduced and characterized. The concepts and results are illustrated through case studies on chemical reactor models. (c) 1999 American Institute of Physics. 相似文献