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101.
The steady viscous incompressible and slightly conducting fluid flow around a circular cylinder with an aligned magnetic field is simulated for the range of Reynolds numbers 100 ? Re ? 500 using the Hartmann number, M. The multigrid method with defect correction technique is used to achieve the second order accurate solution of complete non-linear Navier–Stokes equations. The magnetic Reynolds number is assumed to be small. It is observed that volume of the separation bubble decreases and drag coefficient increases as M is increased. We noticed that the upstream base pressure increases slightly with increase of M whereas downstream base pressure decreases with increase of M. The effect of the magnetic field on the flow is discussed with contours of streamlines, vorticity, plots of surface pressure and surface vorticity. 相似文献
102.
Yonzon CR Jeoung E Zou S Schatz GC Mrksich M Van Duyne RP 《Journal of the American Chemical Society》2004,126(39):12669-12676
A comparative analysis of the properties of two optical biosensor platforms: (1) the propagating surface plasmon resonance (SPR) sensor based on a planar, thin film gold surface and (2) the localized surface plasmon resonance (LSPR) sensor based on surface confined Ag nanoparticles fabricated by nanosphere lithography (NSL) are presented. The binding of Concanavalin A (ConA) to mannose-functionalized self-assembled monolayers (SAMs) was chosen to highlight the similarities and differences between the responses of the real-time angle shift SPR and wavelength shift LSPR biosensors. During the association phase in the real-time binding studies, both SPR and LSPR sensors exhibited qualitatively similar signal vs time curves. However, in the dissociation phase, the SPR sensor showed an approximately 5 times greater loss of signal than the LSPR sensor. A comprehensive set of nonspecific binding studies demonstrated that this signal difference was not the consequence of greater nonspecific binding to the LSPR sensor but rather a systematic function of the Ag nanoparticle's nanoscale structure. Ag nanoparticles with larger aspect ratios showed larger dissociation phase responses than those with smaller aspect ratios. A theoretical analysis based on finite element electrodynamics demonstrates that this results from the characteristic decay length of the electromagnetic fields surrounding Ag nanoparticles being of comparable dimensions to the ConA molecules. Finally, an elementary (2 x 1) multiplexed version of an LSPR carbohydrate sensing chip to probe the simultaneous binding of ConA to mannose and galactose-functionalized SAMs has been demonstrated. 相似文献
103.
S. N. Bhadani Madhu Tiwari Archana Agrawal Chandra Sekhar Kavipurapu 《Mikrochimica acta》1994,117(1-2):15-22
A sensitive Spectrophotometric method for the determination of iron with tiron and a cationic surfactant, cetylpyridinium chloride, at pH 5.6 is reported. The complex is extracted into a chloroform-propan-2-ol (41) mixture and shows maximum absorbance at 520 nm. Beer's law is obeyed in the range 1–14 g/ml with an average molar absorptivity of 15800 l mol–1 cm–1. The molar ratio as determined by Job's method for Fe:tiron:CPC is 143. Interferences by various ions are examined. Zr, Ti and Mo interfere heavily. The method is applied for the determination of iron in Al-based and Cu-based alloys, using appropriate masking agents. 相似文献
104.
Ghosh Kamal Kumar Ray Dipankar Chanda Pranab 《International Journal of Theoretical Physics》1989,28(1):111-117
We present the complete set of solutions of the coupled differential equations of the form ()2=(), 2
=(). Equations of this form appear in several physical situations. 相似文献
105.
A quick, economic synthesis of the alkaloid 1, an inhibitor of mycothiol-S-conjugate amidase (MCA) is reported. Starting from low-cost, commercially available 4-hydroxybenzaldehyde, the nine-step synthesis involved dibromination and coupling with N-acetylglycine to give a stable methyloxazole intermediate 5 which was hydrolyzed, oximated and coupled to agmatine to yield the oxime in ∼30% overall yield. It was not necessary to protect the oxime in the synthetic sequence thereby circumventing a deprotection step. 相似文献
106.
S. N. Bhadani Madhu Tewari Archana Agrawal K. Chandra Sekhar 《Analytical and bioanalytical chemistry》1994,349(6):478-481
A red, water-soluble complex of nickel with PAR can be extracted into chloroform with CTAB at pH 7.0. The system obeys Beer's law upto 0.5 μg/ml with a molar absorptivity of 45 200 L·mol?1·cm?1 at 540 nm. Job's method of continuous variations revealed that the composition of the extracting species is 1:2:2 for nickel:PAR:CTAB. Based on this extraction, a highly sensitive and selective spectrophotometric method for the determination of nickel in polymetallic sea-bed nodules and in steels, after prior separation of iron and manganese, was developed. The standard deviation was 0.04–0.127 μg for 5–25 μg of nickel. 相似文献
107.
Radha Rani Chinthaparthi Chandra Sekhar Reddy Gangireddy Veeranarayana Reddy Mudumala Mohan Gundluru Nagaraju Chamarthi Suresh Reddy Cirandur 《Tetrahedron letters》2013
An efficient and simple protocol is reported for the synthesis of a new class of 1-substituted-octahydro-[1,3,2]diazaphospholo[1,5-a]pyridine-1-oxides in good to excellent yield (88–95%) via Michaelis–Arbuzov rearrangement. Condensation of diamido phosphite with various halides at 60 °C using CeCl3·7H2O as a highly efficient catalyst afforded the products within a short period of reaction time. This procedure is mild, efficient, and non-toxic and stability of the catalyst is the merit of this process. Therefore, this protocol being environmentally benign and efficient, serves as an alternative procedure for the preparation of the title compounds. 相似文献
108.
Ratha Satyajit Vernekar Dnyanesh Sivaneri Kavin Jagadeesan Dinesh Rout Chandra Sekhar 《Journal of Solid State Electrochemistry》2017,21(6):1665-1674
Journal of Solid State Electrochemistry - In this work, we report the synthesis and electrode applications of iron-carbon nanohybrid particles prepared by carbonization of a nanocomposite of FeOOH... 相似文献
109.
Positivity - In this article, we will prove the existence of infinitely many positive weak solutions to the following nonlocal elliptic PDE. $$\begin{aligned} (-\Delta )^s u&= \frac{\lambda... 相似文献
110.
Sayan Biswas Amit Kar Joydeb Chanda Nanaocha Sharma Pardeep Kumar Bharadwaj Pallab Kanti Haldar Pulok Kumar Mukherjee 《Biomedical chromatography : BMC》2022,36(5):e5328
A rapid validated ultra-fast liquid chromatography–photodiode array detector (UFLC-PDA) method was developed to identify and quantify ayapanin (AY) and umbelliferone (UM) simultaneously in Ayapana triplinervis Vahl methanolic extract. The method was validated for linearity, limit of detection (LOD; 3:1σ/S), limit of quantification (LOQ; 10:1σ/S), precision, accuracy, specificity and robustness. The response was linear with a good correlation between concentration and mean peak area through a correlation coefficient of 0.9996, y = 7025.7x – 2269.8 and 0.9997, y = y = 16,262x – 946 with LOD of 6.256 ± 0.52 and 3.325 ± 0.36, and LOQ of 18.838 ± 0.18 and 8.870 ± 0.85 for AY (0.67% w/w) and UM (0.18% w/w), respectively. The relative standard deviation (%) of precision and recovery of AY and UM was <2.0%. The proposed method was simple, accurate, specific, precise and reproducible. 相似文献