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341.
Ričardas Buividas Narges Fahim Jurga Juodkazytė Saulius Juodkazis 《Applied Physics A: Materials Science & Processing》2014,114(1):169-175
The actual surface area of a gold-coated conductive layer over the laser nano-textured surface of sapphire is determined using an electrochemical cyclic voltammetry. The method is down scaled to measure the sensing surface area of 200 × 200 μm2 on a laser-ablated ripple sensor used for surface-enhanced Raman spectroscopy/scattering (SERS). Ripple SERS sensors made on different substrates of high refractive index materials such as GaP, diamond, SiC, and Al2O3 make a versatile sensing platform with the detection of analyte (here a thiophenol) down to 10 nM concentrations. Direct measurement of the surface area provides a powerful tool to investigate roughness, porosity, and morphology of coatings used for SERS or other light harvesting surfaces such as solar cells. Novelty of the proposed method is in the use of cathodic peak of surface passivation–activation cycle for calculation of surface charge. The method enables high-accuracy surface area measurements from as small as 0.01 mm2 pads up to functional solar cells. 相似文献
342.
In this paper, we discuss some basic properties of uniform fractal interpolation functions (FIFs), which is a special class of FIFs, on Sierpinski gasket. We firstly study the min-max property of uniform FIFs. Then we present a necessary and sufficient condition such that uniform FIFs have finite energy. Normal derivative and Laplacian of uniform FIFs are also discussed. 相似文献
343.
Choi R Kim BH Naowaboot J Lee MY Hyun MR Cho EJ Lee ES Lee EY Yang YC Chung CH 《Experimental & molecular medicine》2011,43(12):676-683
Diabetic nephropathy is the most serious complication in diabetes mellitus. It is known that oxidative stress and inflammation play a central role in the development of diabetic nephropathy. In this study, we investigated that ferulic acid (FA) known as anti-oxidative agent could effect on diabetic nephropathy by anti-oxidative and anti-inflammatory mechanism. We examined the effects of FA in obese diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats and non-diabetic control Long-Evans Tokushima Otsuka (LETO) rats. We treated FA to experimental rats from 26 to 45 weeks of age. We evaluated ACR, MDA and MCP-1 in 24 h urine and examined renal histopathology and morphologic change in extracted kidneys from rats. Also, we evaluated the ROS production and MCP-1 levels in cultured podocyte after FA treatment. In the FA-treated OLETF rats, blood glucose was significantly decreased and serum adiponectin levels were increased. Urinary ACR was significantly reduced in FA-treated OLETF rats compared with diabetic OLETF rats. In renal histopathology, FA-treated OLETF rats showed decreased glomerular basement membrane thickness, glomerular volume, and mesangial matrix expansion. FA treatment decreased oxidative stress markers and MCP-1 levels in 24 h urine of rats and supernatants of cultured podocyte. In conclusion, it was suggested that FA have protective and therapeutic effects on diabetic nephropathy by reducing oxidative stress and inflammation. 相似文献
344.
Dr. Da‐Young Sung Dr. Jayavant L. Gunjakar Dr. Tae Woo Kim Dr. In Young Kim Yu Ri Lee Prof. Seong‐Ju Hwang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(22):7109-7117
A new prompt room temperature synthetic route to 2D nanostructured metal oxide–graphene‐hybrid electrode materials can be developed by the application of colloidal reduced graphene oxide (RGO) nanosheets as an efficient reaction accelerator for the synthesis of δ‐MnO2 2D nanoplates. Whereas the synthesis of the 2D nanostructured δ‐MnO2 at room temperature requires treating divalent manganese compounds with persulfate ions for at least 24 h, the addition of RGO nanosheet causes a dramatic shortening of synthesis time to 1 h, underscoring its effectiveness for the promotion of the formation of 2D nanostructured metal oxide. To the best of our knowledge, this is the first example of the accelerated synthesis of 2D nanostructured hybrid material induced by the RGO nanosheets. The observed acceleration of nanoplate formation upon the addition of RGO nanosheets is attributable to the enhancement of the oxidizing power of persulfate ions, the increase of the solubility of precursor MnCO3, and the promoted crystal growth of δ‐MnO2 2D nanoplates. The resulting hybridization between RGO nanosheets and δ‐MnO2 nanoplates is quite powerful not only in increasing the surface area of manganese oxide nanoplate but also in enhancing its electrochemical activity. Of prime importance is that the present δ‐MnO2–RGO nanocomposites show much superior electrode performance over most of 2D nanostructured manganate systems including a similar porous assembly of RGO and layered MnO2 nanosheets. This result underscores that the present RGO‐assisted solution‐based synthesis can provide a prompt and scalable method to produce nanostructured hybrid electrode materials. 相似文献
345.
The reaction of the lithio derivative of novel polyethylene glycol (PEG)‐supported α‐phenylselenopropionate with aldehydes, followed by oxidation–elimination with 30% hydrogen peroxide and then treatment with sodium nitrite, formed PEG‐bound 2‐nitromethyl‐2‐alkenoates. Subsequent cleavage from the PEG efficiently afforded methyl (E)‐2‐nitromethyl‐2‐alkenoates in good yields and high purities. 相似文献
346.
Baji Shaik Ji Hee Park Tae Kyu An Young Ri Noh Soon Byung Yoon Chan Eon Park Young Jin Yoon Yun-Hi Kim Sang-Gyeong Lee 《Tetrahedron》2013
Anthracene and thiophene compounds are promising materials for OTFTs. We report here, the synthesis, as well as the physical, thermal, and optoelectronic properties of alkyl-substituted asymmetric anthracene–thiophene compounds connected by a bridged triple bond. The target molecules were synthesized using 2-bromoanthracene as the starting material, and the proceeding reactions included alkylation, bromination, and the Sonogashira coupling reaction. The synthesized compounds were both thermally and electrochemically stable. Among the synthesized compounds, HTEA (7a) and DTEA (7b) showed mobility and on/off ratio values of 1.3×10−1 cm2/V s, 2.6×106 and 2.0×10−2 cm2/V s, 1.0×106, respectively. 相似文献
347.
Influence of cationic composition and pH on the formation of metal stearates at oil-water interfaces
de Ruiter R Tjerkstra RW Duits MH Mugele F 《Langmuir : the ACS journal of surfaces and colloids》2011,27(14):8738-8747
We study the formation of layers of metal stearates at the interface between a decane solution of stearic acid and aqueous salt solutions of variable composition and pH by monitoring the evolution of their mechanical, optical, and chemical properties as a function of time after formation of the interface. For values of the pH below the pK(a) of stearic acid hardly any interfacial activity is observed. For pH > pK(a), stearic acid deprotonates at the interface and forms metal stearates, eventually leading to the formation of macroscopic solid layers. Dynamic interfacial tension measurements reveal that the process takes place in several stages, which we attribute to the successive formation of dilute and dense monolayers followed by three-dimensional growth. In the presence of divalent ions, the solid layers display a significant increase in the dilatational storage modulus. Experiments performed with an aqueous phase containing multiple cation species (artificial seawater) give rise to particularly pronounced growth of solid layers, which preferentially incorporate Ca(2+) as revealed by X-ray photoelectron and infrared spectroscopy. Our results highlight in particular the importance of the complex synergistic effects of simultaneously present monovalent and divalent cation species on the interfacial adsorption. 相似文献
348.
349.
Jang Yeol Lee Hyuck Sik Wang Bye Ri Yoon Man Jae Han Jae Young Jho 《Macromolecular rapid communications》2010,31(21):1897-1902
On purpose to develop a polymer actuator with high stability in air‐operation as well as large bending displacement, a series of ionic polymer–metal composites (IPMC) was constructed with poly(styrene sulfonate)‐grafted fluoropolymers as ionomeric matrix and immidazolium‐based ionic liquids (IL) as inner solvent. The prepared IPMC actuators exhibited greatly enhanced bending displacement compared to Nafion‐based actuators. The actuators were stable in air‐operation, maintaining initial displacement for up to 104 cycles or 24 h. Investigating the material parameters and morphology of the IPMCs, high ion exchange capacity of the ionomers resulted in high ion conductivity and robust electrode of IPMC, which synergistically contributed to the high bending performance.