1,024 research outputs found
(E)-2-{3-[4-(Diphenylamino)styryl]-5,5-dimethylcyclohex-2-enylidene}malononitrile
In the title compound, C31H27N3, the cyclohexene ring has an envelope configuration. In the crystal structure, there is an 34 Å3 void around the inversion center, but the low electron density (0.13 e Å−3) in the difference Fourier map suggests no solvent molecule occupying this void. No hydrogen bonding is found in the crystal structure
非甾体抗炎药相关的消化性溃疡并发上消化道出血
Through discussion of 1 elderly case with multiple drug application of upper gastrointestinal bleeding (UGIB), we have summarized non-steroidal anti-inflammatory drugs (NSAIDs) are responsible for peptic ulcer bleeding, then discussed the relationship between drugs and peptic ulcer bleeding, suggested current researches of the factors such as age and Helicobacter pylori infection are bleeding risk to recurrent peptic ulcer complicated with UGIB. At last, we suggested the specifec therapeutic schedule and treat focus in different periods.通过讨论1例有应用多种药物病史的老年上消化道出血病例,分析了导致该患者发生消化性溃疡进而发生上消化道出血的致病因素主要与非甾体类消炎药密切相关,同时讨论了多种药物在致病中的主要作用与促发作用。该患者年龄大,既往有胃溃疡病史,同时有幽门螺杆菌感染则是易于再发消化性溃疡并发上消化道出血的易发因素。根据上述分析提出了具体的治疗方案以及不同时期的治疗重点
Confirming the 115.5-day periodicity in the X-ray light curve of ULX NGC 5408 X-1
The Swift/XRT light curve of the ultraluminous X-ray (ULX) source NGC 5408
X-1 was re-analyzed with two new numerical approaches, Weighted Wavelet
-transform (WWZ) and CLEANest, that are different from previous studies.
Both techniques detected a prominent periodicity with a time scale of
days, in excellent agreement with the detection of the same
periodicity first reported by Strohmayer (2009). Monte Carlo simulation was
employed to test the statisiticak confidence of the 115.5-day periodicity,
yielding a statistical significance of (or ). The robust
detection of the 115.5-day quasi-periodic oscillations (QPOs), if it is due to
the orbital motion of the binary, would infer a mass of a few thousand
for the central black hole, implying an intermediate-mass black hole
in NGC 5408 X-1.Comment: 6 pages, 2 figures, submitted to Research in Astronomy and
Astrophysics (RAA
Selective attachment of benzonitrile on Si(111)-7×7: Configuration, selectivity, and mechanism
The cycloaddition of benzonitrile with Si(111)-7×7 has been investigated as a model system for understanding the interaction of conjugated π-electron systems with Si(111)-7×7 using high-resolution electron energy loss spectroscopy, x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy, scanning-tunneling microscopy (STM), and density-functional-theory calculation (perturbative Beck-Perdew functional in conjugation with a basis set of DN**). Vibrational features of chemisorbed benzonitrile unambiguously demonstrate that the cyano group directly interacts with Si surface dangling bonds, evidenced in the disappearance of C≡N stretching mode around 2256 cm-1 coupled with the appearance of C=N stretching mode at 1623 cm-1 and the retention of all vibrational signatures of phenyl ring. XPS shows that both C 1s and N 1s core levels of the cyano groups display large down-shifts by 2.5 and 1.5 eV, respectively, after chemisorption. A smaller down-shift of ∼0.8 eV is observed for the C 1s core level of phenyl group due to the weaker inductive effect of the formed C=N groups in chemisorbed benzonitrile than that of C≡N groups in physisorbed molecules. Compared with physisorbed molecules, the photoemission from πCN orbitals of chemisorbed benzonitrile is significantly reduced, suggesting the direct involvement of πCN in the surface binding. These experimental results show that the covalent attachment of benzonitrile on Si(111)-7×7 occurs in a selective manner through the (2+2) cycloaddition between the cyano group and the adjacent adatom-rest atom pair. The cycloadduct formed contains an intact phenyl ring protruding into vacuum, retaining aromaticity. This functionalized Si surface may serve as a substrate for further modification or act as an intermediate for fabrication of multilayer organic thin films or materials syntheses in vacuum
Review on the development of kelp industry in Shandong province: A comparative perspective
Shandong and Fujian are two important provinces regarding the development of the seaweed industry, which shared three-fourths of the national seaweed yield in the year 2020. The present study has analyzed the overall situation of the seaweed industry in Shandong and Fujian provinces by comparing annual output, farming area, and species structure. The current status of Laminaria japonica cultivation in two provinces is also compared to the production process, industrial organization, progress, and innovation. On this foundation, the following development strategies are proposed for the seaweed industry in Shandong Province: (1) change the mindset based on the present industrial basis, (2) retain and transform innovative achievements, (3) enhance the services of associations and organizations and (4) construct brands based on current market share
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