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排序方式: 共有1149条查询结果,搜索用时 46 毫秒
921.
The wide use of manganese dioxide(MnO2)as an electrode in all-solid-state asymmetric supercapacitors(ASCs)remains challenging because of its low electrical conductivity.This complication can be circumvented by introducing trivalent gadolinium(Gd)ions into the MnO2.Herein,we describe the successful hydrothermal synthesis of crystalline Gd-doped MnO2 nanorods with Ni(OH)2 nanosheets as cathode,which we combined with Fe3O4/GO nanospheres as anode for all-solid-state ASCs.Electrochemical tests dem on strate that Gd dopi ng sign ifica ntly affected the electrochemical activities of the MnO2,which was further enhanced by introducing Ni(OH)2.The GdMnO2/Ni(OH)2 electrode offers sufficient surface electrochemical activity and exhibits excellent specific capacity of 121.8 mA h g-1,at 1A g-1,appealing rate performance,and ultralong lifetime stability(99.3%retention after 10,000 discharge tests).Furthermore,the GdMnO2/Ni(OH)2//PVA/KOH//Fe3O4/GO solid-state ASC device offers an impressive specific energy density(60.25 W h kg-1)at a high power density(2332 W kg-1).This investigation thus shows its large potential in developing novel approaches to energy storage devices. 相似文献
922.
Yong‐Kyu Kim Bun‐Joo Kim Sung Kwon Kang Sung‐Nak Choi Yong‐Min Lee 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(2):m64-m66
In the title compound, [Cu(N3)2(C15H26N2)], the chiral alkaloid (−)‐l‐sparteine (Sp) acts as a bidentate ligand, with two azide ligands occupying the remaining coordination sites, forming a distorted CuN4 tetrahedron. The dihedral angle between the NSp—Cu—NSp and Nazide—Cu—Nazide planes is 55.3 (2)°. Principal dimensions include Cu—NSp = 2.011 (6) and 2.025 (5) Å, and Cu—Nazide = 1.939 (6) and 1.934 (7) Å. The mid‐point of the NSp⋯NSp line does not lie exactly in the Nazide—Cu—Nazide plane, but is tilted towards one of the NSp atoms by 0.026 Å. 相似文献
923.
Hyun Min Park Hwack Joo Lee Sang Hyun Park Han Ill Yoo 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(12):i131-i132
LaInO3, a promising ion conductor for a holistic solid oxide fuel cell, was synthesized by a solid‐state reaction method. The structure was refined by the Rietveld method using X‐ray powder diffraction data. The structure of LaInO3 is distorted by the in‐phase and antiphase tilting of oxygen octahedra in the a+b−b− system of the InO6 polyhedra. In the Pmna space group, the In atom lies on an inversion centre and the La atom and one of the O atoms lie on a mirror plane. 相似文献
924.
Gantumur Battogtokh Yechan Joo Sharif Md Abuzar Heejun Park Sung-Joo Hwang 《Molecules (Basel, Switzerland)》2022,27(3)
Purpose: Most therapeutic agents have limitations owing to low selectivity and poor solubility, resulting in post-treatment side effects. Therefore, there is a need to improve solubility and develop new formulations to deliver therapeutic agents specifically to the target site. Gelatin is a natural protein that is composed of several amino acids. Previous studies revealed that gelatin contains arginyl-glycyl-aspartic acid (RGD) sequences that become ligands for the integrin receptors expressed on cancer cells. Thus, in this study, we aimed to increase the efficiency of drug delivery into cancer cells by coating drug-encapsulating liposomes with gelatin (gelatin-coated liposomes, GCLs). Methods: Liposomes were coated with gelatin using electrostatic interaction and covalent bonding. GCLs were compared with PEGylated liposomes in terms of their size, zeta potential, encapsulation efficiency, stability, dissolution profile, and cell uptake. Results: Small-sized and physically stable GCLs were prepared, and they showed high drug-encapsulation efficiency. An in vitro dissolution study showed sustained release depending on the degree of gelatin coating. Cell uptake studies showed that GCLs were superior to PEGylated liposomes in terms of cancer cell-targeting ability. Conclusions: GCLs can be a novel and promising carrier system for targeted anticancer agent delivery. GCLs, which exhibited various characteristics depending on the coating degree, could be utilized in various ways in future studies. 相似文献
925.
Min Sang Kim Su Jong Hwang Jong Kwon Han Eun Kyung Choi Heon Joo Park Jin Seok Kim Doo Sung Lee 《Macromolecular rapid communications》2006,27(6):447-451
Summary: A pH‐sensitive block copolymer is synthesized by step polymerization and its pH‐sensitive micellization‐demicellization behavior is studied. This polymer has a hydrophilic MPEG (shell) and hydrophobic but pH‐sensitive poly(β‐amino ester) (core), which can form a self‐assembled micelle. As confirmed by fluorescence spectroscopy and dynamic light scattering (DLS), this polymer shows a sharp pH‐sensitive micellization‐demicellization behavior. It is confirmed that the pH sensitivity is affected by the molecular weight ratio between the MPEG and poly(β‐amino ester).
926.
Seog Joo Kang Sung Il Hong Chong Rae Park 《Journal of polymer science. Part A, Polymer chemistry》2000,38(6):936-942
A new aromatic polyamide containing a pendant ethoxycarbonyl group was successfully synthesized from the reaction between 4,4′‐diamino‐2′‐ethoxycarbonylbenzanilide and terephthaloyl chloride. The new polymer was soluble in organic solvents such as N‐methyl‐2‐pyrrolidone and dimethylacetamide, and a tough and transparent film was cast from the polymer solution with viscosities ranging from 2.6 to 5.6 dL/g. When the polymer film was heat‐treated at a temperature greater than 300 °C, a cyclization reaction occurred between the ethoxycarbonyl group and the adjacent amide bond to form a benzoxazinone unit in the polymer backbone. The thermal decomposition onset temperature of the cyclized film was about 523 °C, which was somewhat lower than that of poly(p‐phenylene terephthalamide) (PPTA; 566 °C); however, the decomposition rate was slower than that of PPTA to yield a higher char residue. The dispersion temperature of the uncyclized poly(4,4′‐diamino‐2′‐ethoxycarbonylbenzanilide terephthalamide) (PDEBTA) was about 340 °C, whereas that of the cyclized PDEBTA was not clear. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 936–942, 2000 相似文献
927.
Moonhor Ree Sang Il Kim Seung Moon Pyo Tae Joo Shin Hong Ki Park Jin Chul Jung 《Macromolecular Symposia》1999,142(1):73-84
New aromatic diamines containing π-conjugated heterocyclic rings were synthesized, which emit blue light in the photoluminescence. Using these new monomers, soluble poly(amic acid)s were prepared by the polycondensations with pyromellitamic dianhydride, and thermally converted to the polyimides in films which emit intense blue-light. These polyimides are considered as potential candidate materials for fabricating optoelectronic devices which emit blue light. In addition, new poly(m-phenylene 4,4′-oxydiphthalimide)s containing various side chains were synthesized. For these polyimides, thermal properties were investigated with considering the chain flexibility of polymer backbone as well as the spacer and biphenyl mesogen end group in the side chains. In particular, these polyimides exhibited excellent performance in the rubbing process and the controlling of both the alignment and the pretilt of liquid-crystal (LC) molecules in the LC cell. This might be attributed mainly to a strong interaction between the biphenyl mesogen end group in the side chains and the mesogen unit of LC molecules. 相似文献
928.
Byungjick Min Yejin Ahn Hyeok-Jun Cho Woong-Kwon Kwak Hyung Joo Suh Kyungae Jo 《Molecules (Basel, Switzerland)》2021,26(23)
Hops contain flavonoids that have sedative and sleep-promoting activities such as α-acid, β-acid, and xanthohumol. In this study, the sleep-enhancing activity of a Saaz–Saphir hops mixture was measured. In the caffeine-induced insomnia model, the administration of a Saaz–Saphir mixture increased the sleep time compared to Saaz or Saphir administration alone, which was attributed to the increase in NREM sleep time by the δ-wave increase. Oral administration of the Saaz–Saphir mixture for 3 weeks increased the γ-amino butyric acid (GABA) content in the brain and increased the expression of the GABAA receptor. As the GABA antagonists picrotoxin and bicuculline showed a decrease in sleep activity, it was confirmed that the GABAA receptor was involved in the Saaz–Saphir mixture activity. In addition, the GABAA receptor antagonist also reduced the sleep activity induced by xanthohumol and humulone contained in the Saaz–Saphir mixture. Therefore, xanthohumol and humulone contained in the Saaz–Saphir mixture showed sleep-promoting activity mediated by the GABAA receptors. The mixture of the Saaz and Saphir hop varieties may thus help mitigate sleep disturbances compared to other hop varieties. 相似文献
929.
930.
Hae Yong Kweon Joo Hong Yeo Kwang Gill Lee Yong Woo Lee Young Hwan Park Joong‐Hee Nahm Chong‐Su Cho 《Macromolecular rapid communications》2000,21(18):1302-1305
Effects of the concentration of poloxamer 407, temperature, and the concentration of sericin on the gelation of silk sericin (SS) were studied. Gelation of SS was accelerated with an increase in poloxamer concentration and temperature. The sol‐gel transition of SS became irreversible with respect to the temperature in the presence of poloxamer, whereas the sol‐gel transition of SS itself was reversible. Infrared (IR) and circular dichroism (CD) spectra show that the conformational change of SS in the presence of poloxamer was accelerated from random coil to β‐structure. X‐ray diffraction and differential scanning calorimetry (DSC) show that the crystalline structure of poloxamer in the mixture was affected by the presence of SS and that its melting temperature was shifted to lower temperature with increasing SS content, indicating an interaction between poloxamer and SS through hydrogen and hydrophobic bondings. 相似文献