We report vertical growth of ferromagnetic and metallic Fe1.3Ge nanowire (NW) arrays on few-layer graphene in a large area, induced by a relatively good epitaxial lattice match. Integrating ...well-aligned NW arrays onto graphene would offer a good opportunity to combine superb material properties of graphene with versatile properties of NWs into novel applications. Fe1.3Ge NWs are also synthesized on highly ordered pyrolytic graphite (HOPG). Fe1.3Ge NWs on graphene and HOPG show quite efficient field emission, which are ascribed to the well-interfaced vertical growth, a pointed tip, and high field-enhancement factor (β) of the NWs. The development of ferromagnetic metal NW−graphene hybrid structures would provide an important possibility to develop graphene-based spintronic, electronic, and optoelectronic devices.
Practical application of surface-enhanced Raman scattering (SERS)-active platforms requires that they provide highly uniform and reproducible SERS signals. Moreover, to achieve highly stable and ...consistent SERS signals, it is important to control the nanostructured gaps of SERS-active platforms precisely. Herein, we report the synthesis of gap-controllable nanoporous plates and their application to efficient, robust, uniform, and reproducible SERS-active platforms. To prepare well-defined nanoporous plates, ultraflat, ultraclean, and single-crystalline Au nanoplates were employed. The Au nanoplates were transformed to AuAg alloy nanoplates by reacting with AgI in the vapor phase. The Ag in the alloy nanoplates was then chemically etched, thus forming well-defined SERS-active nanoporous plates. For the precise control of gaps in the nanoporous plates, we investigated the alloy forming mechanism based on X-ray photoelectron spectroscopy and transmission electron microscopy analyses. According to the mechanism, the composition of Ag was tunable by varying the reaction temperature, thus making the nanostructured gaps of the porous plates adjustable. We optimized the nanoporous plates to exhibit the strongest SERS signals as well as excellent uniformity and reproducibility. The computational simulation also supports the experimental SERS signals of nanoporous plates. Furthermore, we successfully performed label-free detection of a biocide mixture (5-chloro-2-methyl-4-isothiazolin-3-one/2-methyl-4-isothiazol-3-one) up to 10 ppm using Au nanoporous plates. The adoption of single-crystalline Au nanoplates, the novel synthesis method for alloy nanoplates in the vapor phase, and the investigation of alloy forming mechanisms synergistically contributed to the formation of well-defined nanoporous plates. We anticipate that the nanoporous plates will be useful for the practical sensing of trace chemical and biological analytes.
A gold plate with uniform and controllable intra-nanogaps was synthesized by the chemical vapor reaction of AgI vapor and Au nanoplate and subsequent etching and the nanoporous plate exhibited excellent SERS activity.
Structural and Magnetic Properties of Park, Il Jin; Kwon, Woo Jun; Kouh, Taejoon ...
IEEE transactions on magnetics,
2012-April, 2012-04-00, Letnik:
48, Številka:
4
Journal Article
We have investigated the structural and magnetic properties of FeTiTaO 6 . From the Rietveid-refined XRD patterns of FeTiTaO 6 , its crystal structure at room temperature is determined to be the ...rutile structure with lattice constants of α 0 = 4.65 Å, and c 0 = 3.02 Å. The c/a ratio of 0.649 is almost same as the value in the parent rutile TiO 2 , which is 0.644. Based on the temperature dependence of the susceptibility between 3 and 400 K, measured with superconducting quantum interference device (SQUID), the magnetic Neel temperature (T N ), which is defined as temperature of the maximum slope in dM/dT, is determined to be 40 K. The detailed studies of the local structure have been carried out with 57 Co Mossbauer spectroscopy at various temperatures. The Mossbauer spectra of FeTiTaO 6 were composed of two six-line hyperfine patterns below 40 K. Also, the magnetic hyperfine field of FeTiTaO 6 is found to be 472 kOe at 4.2 K. The Mossbauer spectra clearly reveal the presence of the magnetic ordering below 40 K in FeTiTaO 6 .
An analytical method for determining phenol considered priority pollutants of the US EPA and precursor of toxic phenolic compounds by solid-phase extraction (SPE) and high performance liquid ...chromatographic systems (HPLC) equipped with fluorescence and mass selective detectors have been developed. The SPE process for sample preconcentration was performed on a commercially available Oasis HLB cartridge packed with polymeric sorbents. The effect of pH, elution solvent, and elution volume on the recoveries of the analytes were investigated with HPLC/FLD. Average recovery of >87.0% was achieved with 60 mg sorbents using 5 mL of methanol as an elution solvent at pH=3. Priority pollutant이며 페놀성화합물의 전구체인 페놀을 고체상추출법을 이용하여 추출 정제하여 형광검출기와 질량분석기가 각각 장착된 고속액체크로마토그래프를 이용하여 분석하는 방법을 설정하여 보았다. 고체상추출은 고분자성물질이 충진된 Oasis HLB cartridge를 이용하여 최적의 조건을 확립하였으며 이때의 평균회수율은 87.0% 이었다. 형광검출기를 이용한 경우가 질량분석기를 이용한 경우보다 검출한계가 낮았으나 선택성의 측면에서 질량분석기가 우수하였다.
Fluoreszenzsonden In ihrer Zuschrift auf S. 8056 beschreiben H. S. Je, Y.‐T. Chang et al. die Bildgebung lebender Mikroglia mit der Sonde CDr20. Ugt1a7c katalysiert die Glucuronidierung von CDr20, ...was zu roter Fluoreszenz führt.
Microglia, the brain‐resident macrophage, are involved in brain development and contribute to the progression of neural disorders. Despite the importance of microglia, imaging of live microglia at a ...cellular resolution has been limited to transgenic mice. Efforts have therefore been dedicated to developing new methods for microglia detection and imaging. Using a thorough structure–activity relationships study, we developed CDr20, a high‐performance fluorogenic chemical probe that enables the visualization of microglia both in vitro and in vivo. Using a genome‐scale CRISPR‐Cas9 knockout screen, the UDP‐glucuronosyltransferase Ugt1a7c was identified as the target of CDr20. The glucuronidation of CDr20 by Ugt1a7c in microglia produces fluorescence.
Da geht ein Licht auf: Die fluorogene Sonde CDr20 markiert sowohl in vitro als auch in vivo spezifisch Maus‐Mikroglia. Das ermöglicht ihre Visualisierung durch ein Fluoreszenz‐Einschalten, was durch die UDP‐Glucuronosyltransferase Ugt1a7c vermittelt wird. CDr20 könnte somit in der Charakterisierung der Rolle von Mikroglia in der Gehirnentwicklung und der Entwicklung neuronaler Erkrankungen eingesetzt werden.
Fluoreszenzsonden In ihrer Zuschrift auf S. 8056 beschreiben H. S. Je, Y.‐T. Chang et al. die Bildgebung lebender Mikroglia mit der Sonde CDr20. Ugt1a7c katalysiert die Glucuronidierung von CDr20, ...was zu roter Fluoreszenz führt.
Soluble and transparent poly(amide‐imide)s (PAIs) with a glass transition temperature over 300 °C were synthesized from the alicyclic diacid monomers containing a biphenyl unit with two ...trifluoromethyl (CF3) groups. Combination of two isomeric biphenyl units with CF3 groups significantly improves the glass transition temperature of the corresponding PAIs. The increase of unsymmetrical biphenyl units increased the glass transition temperature of the polymers by reducing the average chain packing distance.
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