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101.
Natural germanium and selenium consist of, respectively, five and six stable isotopes. Several of these isotopes have considerable abundances and one should expect to observe the bands of at least six isotopic variants of germanium monoselenide (GeSe). In this paper, for the first time, the results of the high-resolution electronic spectrum of the main transition A1Π-X1Σ+ of the specific isotopomer 74Ge80Se, excited in a microwave discharge and recorded in the 33 500-26 000 cm−1 region using a Fourier transform spectrometer, is discussed. From the rotational analysis of 25 bands involving v″ = 0-12 and v′ = 0-7, accurate vibrational and rotational constants of the A1Π state are determined. The present study has revealed perturbations in the v′ = 6 and 7 levels of the A1Π state. 相似文献
102.
Wuosmaa AH Back BB Baker S Brown BA Deibel CM Fallon P Hoffman CR Kay BP Lee HY Lighthall JC Macchiavelli AO Marley ST Pardo RC Rehm KE Schiffer JP Shetty DV Wiedeking M 《Physical review letters》2010,105(13):132501
We have studied the 1?C(d,p)1?C reaction in inverse kinematics using the Helical Orbit Spectrometer at Argonne National Laboratory. Prior studies of electromagnetic-transition rates in 1?C suggested an exotic decoupling of the valence neutrons from the core in that nucleus. Neutron-adding spectroscopic factors give a different probe of the wave functions of the relevant states in 1?C. Shell-model calculations reproduce both the present transfer data and the previously measured transition rates, suggesting that 1?C may be described without invoking very exotic phenomena. 相似文献
103.
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105.
The discovery of the antibiotic fusidic acid from Fusidium coccineum in 19621 provided a valuable new medicinal agent, highly active against staphylococcal infections. Though various modifications of the tetracyclic structure (I) have so far failed to furnish derivatives with enhanced antibiotic activity2, no analogs of different skeletal configuration have yet been prepared for assessing the significance of the unique stereochemistry of the fusidane framework. For this purpose it would be desirable to have an effective method of attaching the fusidic acid sidechain to the 17-keto group of various steroids or to other ketones. 相似文献
106.
B. Chandrakantha Arun M. Isloor Kishore Sridharan Reji Philip Prakash Shetty Mahesh Padaki 《Arabian Journal of Chemistry》2013,6(1):97-102
In the present investigation we have synthesized a novel series of N-substituted-5-phenyl-1H-pyrazole-4-ethyl carboxylates, which are characterized by 1H NMR, UV–Vis and FT-IR spectroscopy methods. The optical nonlinearity of the compounds in chloroform solution has been studied at 532 nm using 5 ns laser pulses, employing the open-aperture z-scan technique. It is found that compound 3c having carboxylic acid group and ester substituent has maximum nonlinearity. From measurements we conclude that compounds 3c (4-[4-(ethoxycarbonyl)-5-phenyl-1H-pyrazol-1-yl]benzoic acid) and 3e (ethyl 1-(2-bromophenyl)-5-phenyl-1H-pyrazole-4-carboxylate) are potential candidates for optical limiting applications. 相似文献
107.
Rupa Shetty 《Tetrahedron letters》2006,47(46):8021-8024
Several 2,5-disubstituted benzyl alcohols containing a functionalized t-butyl moiety were synthesized via palladium catalyzed α-arylation of methyl isobutyrate and butyronitrile on synthetically useful scales. The resulting benzyl alcohols could then be further elaborated to benzyl amines or other desirable intermediates. 相似文献
108.
David L. Olson Bala Shetty M. A. Venkataramanan Ishwar Murthy 《Annals of Operations Research》1989,20(1):219-232
Network models are attractive because of their computational efficiency. Network applications can involve multiple objective analysis. Multiple objective analysis requires generating nondominated solutions in various forms. Two general methods exist to generate new solutions in continuous optimization: changing objective function weights and inserting objective bounds through constraints. In network flow problems, modifying weights is straightforward, allowing use of efficient network codes. Use of bounds on objective attainment levels can provide a more controlled generation of solutions reflecting tradeoffs among objectives. To constrain objective attainment, however, would require a side constrained network code, sacrificing some computational efficiency for greater model flexibility. We develop reoptimization procedures for the side constrained problem and use them in conjunction with simplex-based techniques. Our approach provides a useful tool for generating solutions allowing greater decision maker control over objective attainments, allowing multiobjective analysis of large-scale problems. Results are compared with solutions obtained from the computationally more attractive weighting technique. Reoptimization procedures are discussed as a means of more efficiently conducting multiple objective network analyses. 相似文献
109.
Li M Schiano JL Samra JE Shetty KK Brey WW 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,212(2):254-264
Resistive and hybrid (resistive/superconducting) magnets provide substantially higher magnetic fields than those available in low-temperature superconducting magnets, but their relatively low spatial homogeneity and temporal field fluctuations are unacceptable for high resolution NMR. While several techniques for reducing temporal fluctuations have demonstrated varying degrees of success, this paper restricts attention to methods that utilize inductive measurements and feedback control to actively cancel the temporal fluctuations. In comparison to earlier studies using analog proportional control, this paper shows that shaping the controller frequency response results in significantly higher reductions in temporal fluctuations. Measurements of temporal fluctuation spectra and the frequency response of the instrumentation that cancels the temporal fluctuations guide the controller design. In particular, we describe a sampled-data phase-lead-lag controller that utilizes the internal model principle to selectively attenuate magnetic field fluctuations caused by the power supply ripple. We present a quantitative comparison of the attenuation in temporal fluctuations afforded by the new design and a proportional control design. Metrics for comparison include measurements of the temporal fluctuations using Faraday induction and observations of the effect that the fluctuations have on nuclear resonance measurements. 相似文献
110.
Juan Jose Pavn Jean Paul Allain Devendra Verma Mnica Echeverry‐Rendn Christy L. Cooper Lisa M. Reece Akshath R. Shetty Vikas Tomar 《Macromolecular bioscience》2019,19(2)
Surgical clipping and endovascular coiling are well recognized as conventional treatments of Penetrating Brain Injury aneurysms. These clinical approaches show partial success, but often result in thrombus formation and the rupture of aneurysm near arterial walls. The authors address these challenging brain traumas with a unique combination of a highly biocompatible biopolymer hydrogel rendered magnetic in a flexible and resilient membrane coating integrated to a scaffold stent platform at the aneurysm neck orifice, which enhances the revascularization modality. This work focuses on the in situ diagnosis of nano‐mechanical behavior of bacterial nanocellulose (BNC) membranes in an aqueous environment used as tissue reconstruction substrates for cerebral aneurysmal neck defects. Nano‐mechanical evaluation, performed using instrumented nano‐indentation, shows with very low normal loads between 0.01 to 0.5 mN, in the presence of deionized water. Mechanical testing and characterization reveals that the nano‐scale response of BNC behaves similar to blood vessel walls with a very low Young´s modulus, E (0.0025 to 0.04 GPa), and an evident creep effect (26.01 ± 3.85 nm s?1). These results confirm a novel multi‐functional membrane using BNC and rendered magnetic with local adhesion of iron‐oxide magnetic nanoparticles. 相似文献