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51.
Giant Hysteretic Sorption of CO2: In Situ Crystallographic Visualization of Guest Binding within a Breathing Framework at 298 K 下载免费PDF全文
Dr. Prem Lama Dr. Himanshu Aggarwal Charl X. Bezuidenhout Prof. Leonard J. Barbour 《Angewandte Chemie (International ed. in English)》2016,55(42):13271-13275
A dynamic ZnII‐MOF has been shown to exhibit extreme breathing behavior under gas pressure. The very narrow pore form of the activated framework opens up in the presence of carbon dioxide, thus making it a suitable material for CO2 capture. Sorption of CO2 at 298 K and relatively high pressure clearly shows a two‐step isotherm with giant hysteresis for the second step. In‐situ single‐crystal diffraction analysis was carried out under CO2 gas pressure at 298 K using an environmental gas cell in order to visualize the interaction between CO2 and the host framework. The results are well supported by pressure‐gradient differential scanning calorimetry (P‐DSC) and variable‐pressure powder X‐ray analysis. Theoretical calculations have been carried out in order to further back up the crystallographic data. 相似文献
52.
M. Guru Prem Prasad 《Journal of Mathematical Analysis and Applications》2007,329(2):1446-1459
Let E denote the class of all transcendental entire functions for z∈C and an?0 for all n?0 such that f(x)>0 for x<0 and the set of all (finite) singular values of f forms a bounded subset of R. For each f∈E, one parameter family is considered. In this paper, we mainly study the dynamics of functions in the one parameter family S. If f(0)≠0, we show that there exists a positive real number λ∗ (depending on f) such that the bifurcation and the chaotic burst occur in the dynamics of functions in the one parameter family S at the parameter value λ=λ∗. If f(0)=0, it is proved that the Julia set of fλ is equal to the complement of the basin of attraction of the super attracting fixed point 0 for all λ>0. It is also shown that the Fatou set F(fλ) of fλ is connected whenever it is an attracting basin and the immediate basin contains all the finite singular values of fλ. Finally, a number of interesting examples of entire transcendental functions from the class E are discussed. 相似文献
53.
Reduction of imine-anthracenone compounds selectively produces secondary alcohols leaving the external imine group unreacted. Addition of the Zn(II) ion induces a metal-mediated imine-enamine tautomerization reaction that is selective for Zn(II), a new fluorescence detection method not previously observed for this important cation. 相似文献
54.
We report on a high rate, ultra-low timing jitter, short optical pulse generator based on cascaded amplitude and phase modulation in an optoelectronic oscillator. The radio-frequency supermodes are shown to be greatly suppressed with the dual-loop architecture, and a highly coherent and flat optical frequency comb is generated. Optical pulses of 12.8 ps duration are obtained with 27.5 fs integrated timing jitter from 100 Hz to 10 MHz. 相似文献
55.
We report near-noiseless (noise figure of 0.4 dB, which is an improvement over the theoretical limit of 1.2 dB for a conventional
laser amplifier with the same gain of 1.7 dB) optical amplification of laser light in a phase-sensitive fibre amplifier. 相似文献
56.
Bayesian latent variable regression (BLVR) aims to utilize all available information for empirical modeling via a Bayesian framework. Such information includes prior knowledge about the underlying variables, model parameters and measurement error distributions. This paper improves upon the existing optimization‐based BLVR (BLVR‐OPT) method [1] by developing a sampling‐based Bayesian latent variable regression (BLVR‐S) method that relies on Gibbs sampling. Use of the sampling‐based framework not only provides point estimates, but its ability to generate samples that represent the posterior distribution of the unknown variables, also readily provides error bounds. Features and advantages of this method are demonstrated via examples based on simulated data and real Near‐Infrared (NIR) spectroscopy data. Practical aspects of Bayesian modeling such as determining when the extra computation may be worth the effort are addressed by an empirical study of the effects of the amount of training data and signal to noise ratio (SNR). The benefits of BLVR seem to be most significant when the number of measurements is limited and when noise in output variables is relatively large. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
57.
Madasu Madhu Sai Reddy Doda Prem Kumar Begari Krishna Rao Dasari Gangadhar Thalari Sudhakar Kadari Jhillu Singh Yadav 《Journal of heterocyclic chemistry》2021,58(4):942-946
Enantioselective and a highly concise total synthesis of Ambrisentan are described. The chiral auxiliary controlled enantioselective epoxidation (Azerad protocol), photochemical regioselective epoxide opening, and base mediated ester hydrolysis reactions are the key reactions. 相似文献
58.
Raman spectra of Cs2ZnI4 single crystal have been measured in different scattering orientations covering the successive phase transitions down to 68 K. Two second order anomalies at around ice temperature (270 K) and at ~ 92 K are observed. The anomaly around ice temperature exhibits the features of a normal-incommensurate transition evidenced by softening of a low-lying lattice phonon whose frequency decreases as the transition temperature is approached from below whereas the latter one appears to arise from usual structural distortions. 相似文献
59.
Jacob Lasri Preetpaul Devgan Vladimir S. Grigoryan Prem Kumar 《Optics Communications》2004,240(4-6):293-298
We demonstrate a novel, polarization-insensitive scheme for multiwavelength nonreturn-to-zero to return-to-zero format conversion at 10 Gb/s rate with significant timing-jitter suppression and signal-to-noise ratio improvement. The scheme utilizes a self-starting electroabsorption-modulator based optoelectronic oscillator that simultaneously generates a 10 GHz-rate microwave signal and a train of 15 ps-wide optical pulses with 40 fs timing jitter (100–10 MHz range). Under direct optical injection locking of the oscillator with an incoming data stream, we demonstrate the extraction of a high-quality clock that enables in-line format conversion of multiple, synchronized nonreturn-to-zero channels. 相似文献
60.
Prem C. Srivastava Clarence E. Guyer Furn F. Knapp 《Journal of heterocyclic chemistry》1983,20(4):1081-1084
Two new 125I-labeled barbituric acid analogs, 5-ethyl-5-(E-1-iodo-1-penten-5-yl)2-thiobarbituric acid ( 4 ) and 5-ethyl-5-( m -iodophenyl)barbituric acid ( 7 ), have been prepared and evaluated in rats as potential cerebral perfusion agents. Annulation of 2-ethyl-2-(E-1-iodo-1-penten-5-yl)malonate ( 3 ) with thiourea in the presence of sodium ethoxide gave the 5-ethyl-5-(E-1-iodo-1-penten-5-y1)-thiobarbituric acid ( 4 ). Diethyl 2-ethyl-2-phenyl-malonate was treated with thallium(III) trifluoroacetate followed by addition of aqueous potassium iodide to provide diethyl 2-ethyl-2-(m-iodophenyl)malonate ( 10 ). The malonic ester derivative 10 was condensed with urea in the presence of sodium hydride to give the desired 5-ethyl-5-(m-iodophenyl)barbituric acid ( 7 ), and a decarbethoxylation product, 2-(m-iodophenyl)butyric acid ( 11 ). Iodine-125-labeled 4 and 7 were synthesized in the same manner and the tissue distribution of these new agents evaluated in rats. Both [125I] 4 and [125I] 7 showed high brain uptake. Significant in vivo deiodination was detected with [125I] 4 whereas [125I] 7 was found to be stable to deiodination. 相似文献