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991.
Partially exfoliated nanocomposite(2) has been synthesized by intercalation of poly(propylene carbonate)(PPC) into commercial clay,Cloisite 20B(PPC/C-20B).Nanocomposite 2 was characterized phiso-chemically and exhibited high thermal,mechanical and anti-water sorption properties as compared to PPC and intercalated nanocomposite(1) of PPC/C-20B having same amount of clay.TGA results revealed that the thermal decomposition temperature(Td,50%) of 2 increased significantly,being 40 K and 17 K higher than that of pure PPC and 1,respectively,while DSC measurements indicated that the nano-filler dispersion of 2 increased the glass transition temperature from 21℃to 31℃.Accordingly,2 showed high elastic modulus,hardness and anti-water absorption capacity.These thermal,mechanical and anti-water absorption improvements are of great importance for the application of PPC as packaging and biomaterials. 相似文献
992.
Kim HG Kim GS Park S Lee JH Seo ON Lee SJ Kim JH Shim JH Abd El-Aty AM Jin JS Shin SC 《Biomedical chromatography : BMC》2012,26(4):464-470
A mixture of flavonoid components was isolated from the fruit peel of three varieties of citrus native to Republic of Korea, Citrus leiocarpa Hort. ex Tanaka (CLHT), Citrus aurantium L. (CAL) and Citrus erythrosa Hort. (CEH), via 70% methanol extraction followed by ethyl acetate elution over a silica gel cartridge. The flavonoid components of the mixture were analyzed via high‐performance liquid chromatography–tandem mass spectrometry (HPLC‐MS/MS) in positive‐ion mode and a comparison of the reported data. Among 17 characterized components, two flavanones, four flavones and two coumarin derivatives in the fruit peel of the three varieties were identified for the first time. The individual characterized components were quantified via HPLC‐UV. The flavanones dominated in CAL, whereas the flavones prevailed in CLHT and CEH. The antioxidant activity of the flavonoid mixture of the fruit peel was determined via DPPH?, ABTS?+ and reducing power assays. The antioxidant activity of CEH and CAL was greater than that of CLHT. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
993.
The importance of symmetry breaking was investigated in bulk heterojunction solar cells with a conventional device structure. Artificial symmetry breaking was built up by introducing a titanium suboxide. With sufficient symmetry breaking, the influence of the cathode work-function can be diminished, thereby extracting the same level of open circuit voltage regardless of metal work-function. 相似文献
994.
P Bhunia E Hwang Y Yoon E Lee S Seo H Lee 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(39):12207-12212
n-Type graphene: A new, easy, and cheap method to produce n-type reduced graphene oxide was developed by synthesizing a partially reduced intermediate containing nitrogen (PrGO-IL, see scheme) by treating graphene oxide (GO) with an ionic liquid (IL) at 160?°C followed by rapid thermal annealing (RTA) at temperatures ranging from 400 to 1000?°C. A high N-doping level of 6?% was achieved and the N-doped rGO exhibits n-type behavior with a Dirac point at -38?V at 400?°C. 相似文献
995.
Some S Bhunia P Hwang E Lee K Yoon Y Seo S Lee H 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(25):7665-7670
A simple chemical method to obtain bulk quantities of N-doped, reduced graphene oxide (rGO) sheets (see figure) as an n-type semiconductor through the treatment of as-prepared GO sheets with the commonly used reducing reagent hydrazine, followed by rapid thermal annealing (RTA) is described. 相似文献
996.
Primary amides are unique supramolecular synthons possessing two hydrogen donors and two hydrogen acceptors. By interacting in a complementary fashion, primary amides reliably generate two-dimensional hydrogen bonded networks that differ from conventional hydrogen bonded structures such as carboxylic acid dimers or one-dimensional secondary amide chains. This feature permits the design of sophisticated supramolecular assemblies based on primary amides (especially aromatic amides). Several interesting crystal structures have been constructed utilizing primary amides, although such structures have been applied only in the field of crystal engineering because the networks strongly favor crystallization. Expansion of the applications of primary amides to liquid crystals and self-assembly in solution requires an appropriate balance between primary amide-based hydrogen bonding and other noncovalent interactions. This perspective article reviews the key hydrogen bonding properties of primary amides determined from crystal structure studies, and a variety of supramolecular assemblies involving primary amides are discussed. A new strategy for overcoming crystallinity and solubility issues is proposed, involving introduction of a trifluoromethyl group at the ortho position of the aromatic primary amide. Such substitutions produce highly processable primary amides, while maintaining the two-dimensional hydrogen bonded network. Examples of self-assembly using 2-trifluoromethylbenzamide demonstrate its usefulness in self-assembly. 相似文献
997.
The first example of the encapsulation of living yeast cells with multilayers of GO nanosheets via LbL self-assembly is reported. The GO nanosheets with opposite charges are alternatively coated onto the individual yeast cells while preserving the viability of the yeast cells, thus affording a means of interfacing graphene with living yeast cells. This approach is expanded by integrating other organic polymers or inorganic nanoparticles to the cells by hybridizing the entries with GO nanosheets through LbL self-assembly. It is demonstrated that incorporated iron oxide nanoparticles can deliver magnetic properties to the biological systems, allowing the integration of new physical and chemical functions for living cells with a combination of GO nanosheets. 相似文献
998.
Eom MS Jang W Lee YS Choi G Kwon YU Han MS 《Chemical communications (Cambridge, England)》2012,48(45):5566-5568
In this study, the use of bi-ligand co-functionalized gold nanoparticles in a highly selective and sensitive colorimetric probe for Ca(2+) ions is demonstrated and this probe also determined the concentrations of Ca(2+) ions in serum samples. 相似文献
999.
A new approach to protodecarboxylation is described that enhances the substrate scope for benzoic acids. The reaction uses oxidative radical conditions to decarboxylate a variety of acids in acetonitrile. 相似文献
1000.