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21.
Aryl pyridyl ethers were prepared from phenols and active halopyridines under essentially neutral condition via fluoride ion assisted reaction. 相似文献
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K.C. Devarayapalli S.V. Prabhakar Vattikuti T.V.M. Sreekanth Ki Soo Yoo P.C. Nagajyothi Jaesool Shim 《应用有机金属化学》2020,34(3):e5376
Herein, cobalt (Co)-based metal–organic zeolitic imidazole frameworks (ZIF-67) coupled with g-C3N4 nanosheets synthesized via a simple microwave irradiation method. SEM, TEM and HR-TEM results showed that ZIF-67 were uniformly dispersed on g-C3N4 surfaces and had a rhombic dodecahedron shape. The photocatalytic properties of g-C3N4/ZIF-67 nanocomposite were evaluated by photocatalytic dye degradation of crystal violet (CV), 4-chlorophenol (4-CP) and photocatalytic hydrogen (H2) production. In presence of visible light illumination, the photocatalytic dye results showed that 95% CV degradation and 53% 4-CP degradation within 80 min. The H2 production of the g-C3N4/ZIF-67 composite was 2084 μmol g−1, which is 3.84 folds greater than that of bare g-C3N4 (541 μmol g−1). 相似文献
26.
Choon Ki Ahn 《Journal of Optimization Theory and Applications》2012,154(2):573-587
This paper is concerned with the delay-dependent exponential robust filtering problem for switched Hopfield neural networks with time-delay. A new delay-dependent switched exponential robust filter is proposed that results in an exponentially stable filtering error system with a guaranteed robust performance. The design of the switched exponential robust filter for these types of neural networks can be achieved by solving a linear matrix inequality (LMI), which can be easily facilitated using standard numerical packages. An illustrative example is given to demonstrate the effectiveness of the proposed filter. 相似文献
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Tuning of Supramolecular Architectures of l‐Valine‐Containing Dicyanoplatinum(II) 2,2′‐Bipyridine Complexes by Metal–Metal, π–π Stacking,and Hydrogen‐Bonding Interactions
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Heidi Li‐Ki Fu Dr. Charlotte Po Dr. Hexiang He Dr. Sammual Yu‐Lut Leung Prof. Kam Sing Wong Prof. Dr. Vivian Wing‐Wah Yam 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(33):11826-11836
A series of newly synthesized dicyanoplatinum(II) 2,2′‐bipyridine complexes exhibits self‐assembly properties in solution after the incorporation of the l ‐valine amino units appended with various hydrophobic motifs. These l ‐valine‐derived substituents were found to have critical control over the aggregation behaviors of the complexes in the solution state. On one hand, one of the complexes was found to exhibit interesting circularly polarized luminescence (CPL) signals at low temperature due to the formation of chiral spherical aggregates in the temperature‐dependent studies. On the other hand, systematic transformation from less uniform aggregates to well‐defined fibrous and rod‐like structures via Pt???Pt and π–π stacking interactions has also been observed in the mixed‐solvent studies. These changes were monitored by UV/Vis absorption, emission, circular dichroism (CD), and CPL spectroscopies, and morphologies were studied by electron microscopy. 相似文献
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Choon Ki Ahn 《Nonlinear dynamics》2012,67(1):573-586
In this paper, a new exponential state estimation method is proposed for switched Hopfield neural networks based on passivity
theory. Through available output measurements, the main purpose is to estimate the neuron states such that the estimation
error system is exponentially stable and passive from the control input to the output error. Based on augmented Lyapunov–Krasovskii
functional, Jensen’s inequality, and linear matrix inequality (LMI), a new delay-dependent state estimator for switched Hopfield
neural networks can be achieved by solving LMIs, which can be easily facilitated by using some standard numerical packages.
The unknown gain matrix is determined by solving delay-dependent LMIs. Finally, a numerical example is provided to demonstrate
the effectiveness of the proposed method. 相似文献
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Ultrastructural aspects of leaf epicuticular wax structures were investigated in the garden strawberry Fragaria × ananassa by scanning and transmission electron microscopy. Both the adaxial and abaxial surfaces of two cultivars (Maehyang and Red Pearl) were collected and subjected to surface observations and ultrathin sections. The most prominent leaf epicuticular wax structures included membraneous platelets and angular rodlets. Most wax platelets were membraneous, and appeared to protrude from the surface at an acute angle. Angular rodlets were usually bent and had rather distinct facets in the abaxial surface of the two cultivars. Membraneous platelets were predominant on the adaxial surface of Maehyang, whereas the adaxial surface of Red Pearl was characterized by angular rodlets. However, both cultivars possessed angular rodlets on the abaxial surface, simultaneously. The combination of air-drying without vacuum and in-lens imaging of secondary electron signals with a field emission gun could impart the superb resolution at low electron dose with minimal specimen shrinkage. In vertical profiles of the leaf epidermis, epicuticular waxes were observed above the cuticle layer, and measured approximately as 50 nm in thickness. The natural epicuticular waxes were seemingly mixtures of electron-dense microfibrils, and heterogeneous in shape on ultrathin sections. Distinct crystal-like strata could be hardly discernable in the wax structures. These results suggest that the garden strawberry has the nature of syntopism within one plant and polymorphism within the same species in the formation and occurrence of leaf epicuticular waxes. 相似文献