排序方式: 共有63条查询结果,搜索用时 31 毫秒
31.
Nak Eun Cho Oh Sang Kwon H.M. Srivastava 《Journal of Mathematical Analysis and Applications》2004,300(2):353-520
Making use of a multiplier transformation, which is defined here by means of the Hadamard product (or convolution), the authors introduce some new subclasses of meromorphic functions and investigate their inclusion relationships and argument properties. Some integral-preserving properties in a given sector are also considered. 相似文献
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Nak Eun Cho 《Journal of Mathematical Analysis and Applications》2003,286(1):168-176
The purpose of the present paper is to investigate some integral preserving properties for certain analytic functions in the open unit disk. We also obtain the conditions for close-to-convex functions in a sector. Our results contain some interesting corollaries as the special cases. 相似文献
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Keung Shik Park Nak Bae Kim Young Suk Kim Kil Yong Lee Han Woo Choi Yoon Yeol Yoon 《Journal of Radioanalytical and Nuclear Chemistry》1988,123(2):585-592
A radiochemical separation method has been applied for determining uranium, thorium and other impurities in molybdenum metallic powder. The impurities of Na, K, Sm, Cr, Zr, Cs, Rb, Zn, Fe, Co and La were separated with a cation exchange resin, and uranium and thorium were, then, separated with an anion exchange resin. The content of impurities were determined by a single comparator method using two monitors, gold and cobalt. 相似文献
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Misgina Tilahun Tsehaye Getachew Teklay Gebreslassie Nak Heon Choi Diego Milian Vincent Martin Peter Fischer Jens Tübke Nadia El Kissi Mateusz L. Donten Fannie Alloin Cristina Iojoiu 《Molecules (Basel, Switzerland)》2021,26(13)
The membrane is a crucial component of Zn slurry–air flow battery since it provides ionic conductivity between the electrodes while avoiding the mixing of the two compartments. Herein, six commercial membranes (Cellophane™ 350PØØ, Zirfon®, Fumatech® PBI, Celgard® 3501, 3401 and 5550) were first characterized in terms of electrolyte uptake, ion conductivity and zincate ion crossover, and tested in Zn slurry–air flow battery. The peak power density of the battery employing the membranes was found to depend on the in-situ cell resistance. Among them, the cell using Celgard® 3501 membrane, with in-situ area resistance of 2 Ω cm2 at room temperature displayed the highest peak power density (90 mW cm−2). However, due to the porous nature of most of these membranes, a significant crossover of zincate ions was observed. To address this issue, an ion-selective ionomer containing modified poly(phenylene oxide) (PPO) and N-spirocyclic quaternary ammonium monomer was coated on a Celgard® 3501 membrane and crosslinked via UV irradiation (PPO-3.45 + 3501). Moreover, commercial FAA-3 solutions (FAA, Fumatech) were coated for comparison purpose. The successful impregnation of the membrane with the anion-exchange polymers was confirmed by SEM, FTIR and Hg porosimetry. The PPO-3.45 + 3501 membrane exhibited 18 times lower zincate ions crossover compared to that of the pristine membrane (5.2 × 10−13 vs. 9.2 × 10−12 m2 s−1). With low zincate ions crossover and a peak power density of 66 mW cm−2, the prepared membrane is a suitable candidate for rechargeable Zn slurry–air flow batteries. 相似文献
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Treatment of dry M(2+)-exchanged zeolite Y (M(2+) = Cd(2+), Mn(2+), and Zn(2+)) with dry H(2)S leads to the formation of isolated, ligand-free, subnanometer MS quantum dots (QDs) in zeolite Y with no framework destruction and with H(+) as the countercation. Treatment of the dry H(+)/CdS QD-incorporating zeolites Y with dry NH(3) leads to the neutralization of H(+) to NH(4)(+). During this process, the framework structure remains intact. However, small amounts of interconnected CdS QDs were formed within the zeolite Y by coalition of isolated CdS QDs at the windows. With H(+) as the countercation, isolated CdS QDs rapidly aggregate into interconnected and mesosized QDs with accompanying destruction of ~50% of sodalite cages leading to the framework rupture. With NH(4)(+) as the countercation, however, the isolated QDs and zeolite framework remain intact even after exposure to the moist air for 4 weeks. Interestingly, the interconnected QDs that were formed during neutralization of H(+) with NH(3) disintegrate into isolated QDs in the air. Similar results were obtained from ZnS and MnS QDs generated in zeolite Y. Thus, ligand-free, naked, subnanometer QDs can now be safely preserved within zeolite pores under the ambient conditions for long periods of time. This finding will expedite the generation and dispersion of various QDs in zeolite pores, their physicochemical studies, and applications. 相似文献
36.
Jeong NC Prasittichai C Hupp JT 《Langmuir : the ACS journal of surfaces and colloids》2011,27(23):14609-14614
Localized surface plasmon resonance (LSPR) by silver nanoparticles that are photochemically incorporated into an electrode-supported TiO(2) nanoparticulate framework enhances the extinction of a subsequently adsorbed dye (the ruthenium-containing molecule, N719). The enhancement arises from both an increase in the dye's effective absorption cross section and a modest increase in the framework surface area. Deployment of the silver-modified assembly as a photoanode in dye-sensitized solar cells leads to light-to-electrical energy conversion with an overall efficiency of 8.9%. This represents a 25% improvement over the performance of otherwise identical solar cells lacking corrosion-protected silver nanoparticles. As one would expect based on increased dye loading and electromagnetic field enhanced (LSPR-enhanced) absorption, the improvement is manifested chiefly as an increase in photocurrent density ascribable to improved light harvesting. 相似文献
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Nak Shin Jung 《Tetrahedron letters》2010,51(9):1291-5907
Resorcin[4]arene-based tetramidocavitands containing four secondary amide groups on their upper rim showed strong (R = methyl or ethyl) binding properties. The caviplex formation through hydrogen bonds of -(CO)N-H?X− was supported by 1H NMR and crystal structure analyses. In a mixture of C2D2Cl4/DMSO/D2O = 5:15:2 at 25 °C, the thermodynamic parameters for caviplex @1, ΔG (kcal mol−1), ΔH (kcal mol−1), and ΔS (cal K−1 mol−1), are −3.7, −8.6, and −16.7, respectively. 相似文献
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Ethanol-soluble amphiphilic TiO(2) nanoparticles (NPs) of average diameter ~9 nm were synthesized, and an α-terpineol-based TiO(2) paste was readily prepared from them in comparatively few steps. When used for fabrication of photoelectrodes for dye-sensitized solar cells (DSSCs), the paste yielded highly transparent films and possessing greater-than-typical, thickness-normalized surface areas. These film properties enabled the corresponding DSSCs to produce high photocurrent densities (17.7 mA cm(-2)) and a comparatively high overall light-to-electrical energy conversion efficiency (9.6%) when deployed with the well-known ruthenium-based molecular dye, N719. These efficiencies are about ~1.4 times greater than those obtained from DSSCs containing photoelectrodes derived from a standard commercial source of TiO(2) paste. 相似文献