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排序方式: 共有226条查询结果,搜索用时 375 毫秒
181.
Jong In Park June Young Jang Dr. Yoon-Joo Ko Dr. Sang Moon Lee Dr. Hae Jin Kim Prof. Hye-Young Jang Prof. Kyoung Chul Ko Prof. Seung Uk Son 《化学:亚洲杂志》2021,16(11):1398-1402
This work shows that hollow microporous organic polymer (H-MOP-A) with activated internal alkynes as IR probes can be prepared by template synthesis based on acyl Sonogashira-Hagihara coupling at room temperature. The H-MOP-A is a versatile platform in the main chain PSM based on nonradical thiol-yne click reaction. Moreover, an IR peak of internal alkynes in the H-MOP-A is very intense and could be utilized in the monitoring of thiol-yne click-based main chain PSM. The functionalized H-MOP-A with carboxylic acids (H-MOP-CA) showed efficient adsorption toward Ag+ ions. The resultant H-MOP-CA-Ag showed excellent performance in the CO2 fixation to α-alkylidene cyclic compounds. 相似文献
182.
Dr. Viktor Barát Maja Budanovic Si Man Tam Dr. June Huh Dr. Richard D. Webster Dr. Mihaiela C. Stuparu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(15):3231-3235
It is shown in this work that high electron affinity can be combined with high solubility and practical accessibility in corannulene-based electron acceptors. The electron affinity originates from the presence of three different types of electron-withdrawing groups (imide, sulfone, and trifluoromethyl) on the aromatic scaffold. The imide substituent further hosts a long alkyl chain (C18H37) to boast solubility in a wide range of organic solvents. The synthesis is modular and consists of three simple steps from a commonly available corannulene derivative with an overall isolated yield of 22–27 %. 相似文献
183.
The built-in piezoelectric field induced by compressive stress in InGaN/GaN multi-quantum well (MQW) light-emitting diodes (LEDs) was investigated using the electric field dependent electroreflectance (ER) spectroscopic method. InGaN/GaN MQW structures were prepared on sapphire substrates of different thicknesses. Thinning the sapphire substrate enables control of the compressive stress by changing the curvature of the wafer bowing. The wafer bowing-induced mechanical stress alters the piezoelectric field in the InGaN/GaN MQW. The flat band voltage, estimated by measuring the applied reverse bias voltage that induces a 180° phase shift in the ER spectra, was decreased from −11.21 V to −10.51 V by thinning the sapphire substrate thickness from 200 to 60 μm. To calculate the piezoelectric field (Fpz) from the compensation voltage, the depletion width was obtained from the capacitance–voltage measurement. The Fpz estimated from the energy shift in ER peak in a bias range from 0 to −12 V was changed by 110 kV/cm. 相似文献
184.
Controlled Nanopores in Thin Films of Nonstoichiometrically Supramolecularly Assembled Graft Copolymers 下载免费PDF全文
Suk Man Cho Giyoung Song Sun Kak Hwang Richard Hahnkee Kim Jinseong Lee Seunggun Yu Prof. June Huh Prof. Hui Joon Park Prof. Cheolmin Park 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(50):18375-18382
Herein, nanometer‐scale morphologies of graft‐copolymer‐like supramolecular thin films, composed of sulfonic acid terminated polystyrene (SPS) and poly(2‐vinylpyridine) (P2VP), and their application to antireflection coatings were investigated. The intermolecular complexes of SPS and P2VP, formed through nonstoichiometric multiple hydrogen bonding between the sulfonic acid group of SPS and the nitrogen atom in pyridine unit of P2VP, occurring in film deposition allowed for the formation of spherical micelles (with SPS and P2VP as the corona and core, respectively) in the thin film. Interestingly, the domain size of the micelles was tunable from approximately 20 to 90 nm on average by controlling either the blend ratio of components or the concentration of polymer solution. Furthermore, nanoporous thin films could be easily prepared by removing the core of micelle‐based nanostructures by using a simple solvent etching process, leaving sulfonic acid groups on the surface of nanopores, which can be utilized as potential functional sites. Those resultant nanoporous thin films were conveniently employed as an antireflection layer on a glass substrate, giving a maximum 97.8 % transmittance in the visible wavelength range. 相似文献
185.
Sung Hwan Park Dr. Wanuk Choi Hyun June Choi Prof. Suk Bong Hong 《Angewandte Chemie (International ed. in English)》2018,57(30):9413-9418
Silicoaluminophosphate (SAPO) molecular sieves are an important class of microporous materials and are useful for industrial catalysis and separations. They have been synthesized exclusively by the use of expensive and environmentally unfriendly organic structure‐directing agents. Now the synthesis of SAPO molecular sieves is reported with MER, EDI, GIS, and ANA topologies under wholly inorganic conditions. Multinuclear MAS NMR analyses demonstrate the presence of Si, Al, and P atoms in their frameworks. These SAPO materials all have unusually high framework charge densities (0.25–0.46), owing to the small size of alkali metal cations used as an inorganic structure‐directing agent. A continuous Si increase in the synthesis gel for MER‐type SAPO molecular sieves led to the formation of framework Si(0Al) units, decreasing the number of extra‐framework cations per unit cell and thus making the resulting solid useful for CO2 adsorption. 相似文献
186.
Analysis and computational method based on quadratic B‐spline FEM for the Rosenau–Burgers equation 下载免费PDF全文
Guang‐Ri Piao June‐Yub Lee Guo‐Xian Cai 《Numerical Methods for Partial Differential Equations》2016,32(3):877-895
L∞‐error estimates for B‐spline Galerkin finite element solution of the Rosenau–Burgers equation are considered. The semidiscrete B‐spline Galerkin scheme is studied using appropriate projections. For fully discrete B‐spline Galerkin scheme, we consider the Crank–Nicolson method and analyze the corresponding error estimates in time. Numerical experiments are given to demonstrate validity and order of accuracy of the proposed method. © 2015 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 32: 877–895, 2016 相似文献
187.
While 1-(2-arylethynyl)-2-nitroarenes were reduced to 2-(2-arylethynyl)anilines in the presence of indium and InCl3 in THF/H2O (v/v = 5/1) at 50 °C, 1-(2-arylethynyl)-2-nitroarenes were reductively cyclized to 2-arylindoles with good yields in the presence of indium and aqueous HI in benzene. 相似文献
188.
Niamh Holland Patrick Duggan Eleanor Owens Wayne Cummins June Frisby Helen Hughes Peter McLoughlin 《Analytical and bioanalytical chemistry》2008,391(4):1245-1253
A powerful method utilising direct probe thermal desorption GC–MS is presented for the study of molecularly imprinted polymers
(MIPs). A series of 2-aminopyridine (2-apy)-imprinted methacrylic acid–ethyleneglycol dimethacrylate (MAA–EGDMA) copolymers
were prepared under identical conditions but with varying amounts of EGDMA (crosslinking monomer). The use of appropriate
temperature programmes permitted template removal, and the subsequent assessment of polymer affinity and specificity, all
of which were found to be dependent on polymer composition and morphology. The system was sufficiently sensitive to identify
a specific response of imprinted polymers over nonimprinted counterparts. Correlations were found to exist between thermal
desorption analysis and solution phase binding, which was assessed by UV spectroscopy, where specificity was found to diminish
with decreasing EGDMA concentration. This was attributed to the increased number of free carboxyl groups in those polymers
containing a lower percentage of EGDMA. Thermal desorption profiles obtained for the analyte were found to be unaffected by
the physical and chemical properties of the solvent used for analyte reloading.
An erratum to this article can be found at 相似文献
189.
Reduction of aldehydes using decaborane (B10H14) in an aqueous solution gave the corresponding alcohol chemoselectively in good to high yields. 相似文献
190.