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1.
We obtain a solution of the DGLAP equation for the gluon at low x first by expanding the gluon in a Taylor series and then using the method of characteristics. We test its validity by comparing
it with that of Glück, Reya and Vogt. The convergence criteria of the approximation used are also discussed. We also calculate
εF
2(x,Q)2/ε In Q
2 using its approximate relations with the gluon distribution at low x. The predictions are then compared with the HERA data. 相似文献
2.
Overtone spectrum of o, m and p-nitrobenzaldehydes and p-chlorobenzaldehyde has been studied in 2000–12000 cm−1 region. Vibrational frequencies and anharmonicity constants for aryl as well as alkyl CH stretch vibrations have been determined.
We have also determined the internuclear distances for the aryl CH bond in the different molecules. The small variation observed
in these distances is an indication of the substitution effect.
It is observed that in the case of p-disubstituted benzens, the shift in aryl CH bond is proportional to sum of the Hammet σ of the substituents. However in the
case of o-disubstituted benzenes it is only 80% of the para-substituted shift. 相似文献
3.
Sofian M. Kanan Fatin Samara Imad A. Abu-Yousef Naser Abdo Danial Tobias 《Research on Chemical Intermediates》2010,36(5):473-482
Ag (I) nanoclusters doped in mordenite zeolite were prepared and spectroscopically analyzed. Strong luminescence emission
that is dependent on the excitation wavelength was observed. These variations in the emission modes are due to the site selective
luminescence where various luminophores might be excited upon selecting the proper excitation wavelength. The selected material
was found to have strong affinity to remove the quinalphos pesticide, which is widely used for the protection of several vegetable
and fruit crops, from water bodies. HPLC and GC–MS techniques were used to follow the kinetic data and to identify the photodecomposition
products, respectively. The photodecomposition of quinalphos in the presence of the silver doped mordenite catalyst gives
different products compared to the irradiation of quinalphos without catalyst. The presence of the Ag-mordenite catalyst not
only adsorbs the quinalphos from the solution but it also reduces its toxic effect as tested on the fruit fly (Drosophila melanogaster). 相似文献
4.
We have developed and applied an approach to reaction discovery that takes advantage of DNA encoding, DNA-programmed assembly of substrate pairs, in vitro selection, and PCR amplification, yet does not require reaction conditions that support DNA hybridization. This system allows the simultaneous evaluation of >200 potential bond-forming combinations of substrates in a single experiment and can be applied in a range of solvent and temperature conditions. In an initial application, we applied this system to explore Au(III)-mediated chemistry and uncovered a simple, mild method for the selective Markovnikov-type hydroarylation of vinyl arenes and trisubstituted olefins with indoles. 相似文献
5.
Mohd. Imran Mandeep Kumar Arora Syed Mohammed Basheeruddin Asdaq Shah Alam Khan Saleh I. Alaqel Mohammed Kanan Alshammari Mohammed M. Alshehri Ahmed Subeh Alshrari Alreshidi Mateq Ali Ahmed Muteb Al-shammeri Bushra Dhuhayyan Alhazmi Aishah Ali Harshan Md. Tauquir Alam Abida 《Molecules (Basel, Switzerland)》2021,26(19)
The COVID-19 pandemic needs no introduction at present. Only a few treatments are available for this disease, including remdesivir and favipiravir. Accordingly, the pharmaceutical industry is striving to develop new treatments for COVID-19. Molnupiravir, an orally active RdRp inhibitor, is in a phase 3 clinical trial against COVID-19. The objective of this review article is to enlighten the researchers working on COVID-19 about the discovery, recent developments, and patents related to molnupiravir. Molnupiravir was originally developed for the treatment of influenza at Emory University, USA. However, this drug has also demonstrated activity against a variety of viruses, including SARS-CoV-2. Now it is being jointly developed by Emory University, Ridgeback Biotherapeutics, and Merck to treat COVID-19. The published clinical data indicate a good safety profile, tolerability, and oral bioavailability of molnupiravir in humans. The patient-compliant oral dosage form of molnupiravir may hit the market in the first or second quarter of 2022. The patent data of molnupiravir revealed its granted compound patent and process-related patent applications. We also anticipate patent filing related to oral dosage forms, inhalers, and a combination of molnupiravir with marketed drugs like remdesivir, favipiravir, and baricitinib. The current pandemic demands a patient compliant, safe, tolerable, and orally effective COVID-19 treatment. The authors believe that molnupiravir meets these requirements and is a breakthrough COVID-19 treatment. 相似文献
6.
MJ Singh DO Kataria N Madhavan P Sugathan JJ Das DK Awasthi AK Sinha R Shanker 《Pramana》1999,53(4):743-764
A projectile ion-recoil ion coincidence technique has been employed to study the multiple ionization and the charge transfer
processes in collisions of 60–120 MeV Si
q+ (q = 4−14) ions with neutral argon atoms. The relative contribution of different ionization channels, namely; direct ionization,
electron capture and electron loss leading to the production of slow moving multiply charged argon recoil ions have been investigated.
The data reported on the present collision system result from a direct measurement in the considered impact energy for the
first time. The total ionization cross-sections for the recoil ions are shown to scale as q
1.7/E
p
0.5
, where E
p is the energy in MeV of the projectile and q its charge state. The recoil fractions for the cases of total- and direct ionizations are found to decrease with increasing
recoil charge state j. The total ionization fractions of the recoils are seen to depend on q and to show the presence of a ‘shell-effect’ of the target. Further, the fractions are found to vary as 1/j
2 upto j = 8+. The average recoil charge state 〈j〉 increases slowly with q and with the number of lost or captured electrons from or into the projectile respectively. The projectile charge changing
cross-sections σ
qq′ are found to decrease with increasing q for loss ionization and to increase with q for direct-and capture ionization processes respectively. The physics behind various scaling rules that are found to follow
our data for different ionization processes is reviewed and discussed. 相似文献
7.
The importance of tin oxide (SnO(x)) to the efficiency of CO(2) reduction on Sn was evaluated by comparing the activity of Sn electrodes that had been subjected to different pre-electrolysis treatments. In aqueous NaHCO(3) solution saturated with CO(2), a Sn electrode with a native SnO(x) layer exhibited potential-dependent CO(2) reduction activity consistent with previously reported activity. In contrast, an electrode etched to expose fresh Sn(0) surface exhibited higher overall current densities but almost exclusive H(2) evolution over the entire 0.5 V range of potentials examined. Subsequently, a thin-film catalyst was prepared by simultaneous electrodeposition of Sn(0) and SnO(x) on a Ti electrode. This catalyst exhibited up to 8-fold higher partial current density and 4-fold higher faradaic efficiency for CO(2) reduction than a Sn electrode with a native SnO(x) layer. Our results implicate the participation of SnO(x) in the CO(2) reduction pathway on Sn electrodes and suggest that metal/metal oxide composite materials are promising catalysts for sustainable fuel synthesis. 相似文献
8.
We give a unified derivation of a null chart for all spherically symmetric, homothetic spacetimes. These spacetimes contain an interesting class of naked singularities which we are also able to elucidate. Much use is made of graphical representation; in particular a chart of the spacetimes based on their homothetic group motions is introduced. Dust spacetimes, and two homogeneous examples with non-zero pressure (flat Robertson-Walker and a Kantowski-Sachs example) are studied in detail. We show the horizon structure in the null atlas, in comoving coordinates, in terms of the areal radius and comoving time, and in the homothetic diagrams. The critical delay between comoving observers for the onset of nakedness is interpreted in terms of a decreasing mass concentration in the spirit of Thorne's hoop conjecture. We also give a simple criterion for the existence of apparent horizons isolating the various singularities, and study in detail how this criterion is circumvented in the naked examples. We conclude that this type of naked singularity is a consequence of the imposed homothetic symmetry, by showing it to be generally present and timelike in the homothetic group chart even when it is not visible at comoving infinity (before the onset of criticality). It is the delayed final collapse of initially distant observers in inhomogeneous spacetimes that causes the initial singularity to become visible at comoving infinity. We conclude that these examples do not present an obstacle to the Event Horizon Conjecture as summarized by W. Israel (1984). That is, one can formulate criteria for the formation of apparent horizons that do not imply that all singularities are necessarily so enclosed. It is still possible that all singularities stronger than homothetic are isolated by an apparent horizon, in the spirit of Tipler's conjecture.On leave from Department of Physics, Queen's University, Kingston, Ontario, Canada 相似文献
9.
The translation of DNA sequences into synthetic products is a key requirement of our approach to evolving synthetic molecules through iterated cycles of translation, selection, and amplification. Here we report general linker and purification strategies for sequence-specific DNA-templated synthesis that collectively enable the product of a DNA-templated reaction to be isolated and to undergo subsequent DNA-templated reactions. Using these strategies, we have achieved the first multistep nucleic acid-templated small-molecule syntheses to generate two different molecules. In addition to representing a method for translating DNA templates sequence-specifically into corresponding multistep synthetic products, our findings also provide experimental support for previously proposed models invoking multistep nucleic acid-templated synthesis as mediating the prebiotic translation of replicable information into the earliest functional molecules. 相似文献
10.
Moyet Matthew A. Kanan Sofian M. Varney Hannah M. Abu-Farha Nedal Gold Davis B. Lain William J. Pike Robert D. Patterson Howard H. 《Research on Chemical Intermediates》2019,45(12):5919-5933
Research on Chemical Intermediates - Phosphonium iodobismuthates(III) (MePh3P)3[Bi3I12] (1) and (Ph4P)3[Bi3I12] (2) were prepared, and X-ray crystal structures were determined for both complexes.... 相似文献