The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Yoshinori Ando - One of the best experts on this subject based on the ideXlab platform.
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MHS - PRoduction of carbon nanotubes
2012 International Symposium on Micro-NanoMechatronics and Human Science (MHS), 2012Co-Authors: Yoshinori AndoAbstract:First, the historical fact of the discovery of carbon nanotubes is reviewed. Then, pRoduction of high crystallinity multi-walled carbon nanotubes by DC arc discharge evaporation of pure Graphite Rod in pure hydrogen gas is discussed. The smallest carbon nanotubes included in the core of the multi-walled carbon nanotubes are shown. Carbon chain included in the core of the multi-walled carbon nanotubes and their special Raman peaks near 1850cm-1 also are discussed.
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encapsulation of a scandium trimer in c 82
Nature, 1992Co-Authors: Hisanori Shinohara, Yoshinori Ando, Hiroyasu Sato, Masato Ohkohchi, Takeshi Kodama, Tadamasa Shida, Tatsuhisa Kato, Yahachi SaitoAbstract:FULLERENES with metals encapsulated within the carbon cage have been prepared recently1–6. Laser vaporization of a lanthanum-impregnated Graphite Rod yielded an air-stable, solvent-extractable species comprising a single La atom inside a C82 cage1, denoted La@ C82; a cluster containing two La atoms (La2@ C82) was later reported3. Similar techniques applied to Graphite/yttrium Rods have pRoduced Y@ C82 and Y2@ C82 (refs 5, 6). Here we describe the preparation of scandium-containing C82 species, including an encapsulated scandium trimer, Sc3@C82. Mass spectrometry and ESR spectroscopy provide evidence that the Sc3, trimer is indeed trapped within the cage.
Arunas Ramanavicius - One of the best experts on this subject based on the ideXlab platform.
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amperometric nonenzymatic glucose biosensor based on Graphite Rod electRode modified by ni nanoparticle polypyrrole composite
Microchemical Journal, 2021Co-Authors: Gamze Emir, Almira Ramanaviciene, Yusuf Dilgin, Arunas RamanaviciusAbstract:Abstract This study reports non-ezymatic electrocatalytic amperometric glucose biosensor based on a Graphite Rod electRode (GRE) modified with biomimetic-composite consisting of Ni nanoparticles (Ni-NPs) and polypyrrole (Ppy) prepared by 1 cycle electro polymerization of pyrrole monomer (Ni-NPs/Ppy(1)/GRE). During the modification of GRE, the electropolymerization of pyrrole and the electRodeposition of Ni-NPs onto GRE surface were consequentially performed by potential cycling. Surface morphology of Ni-NPs/Ppy(1)/GRE electRode was evaluated by atomic force microscopy and scanning electron microscopy based imaging, and electrochemical characterization of electRodes was performed by electrochemical impedance spectroscopy and cyclic voltammetry. Cyclic voltammograms recorded in the presence of glucose show that Ni-NPs/Ppy(1)/GRE at +500 mV vs Ag/AgCl exhibits efficient electrocatalytic oxidation activity towards glucose, while the oxidation of glucose was not observed at a bare GRE. Amperometric sensing of glucose was performed by Ni-NPs/Ppy(1)/GRE at constant +450 mV vs Ag/AgCl electRode potential in 0.10 mol L-1 NaOH. Ni-NPs/Ppy(1)/GRE-based sensor, which was characterized by a wide linear glucose determination range between 1.0 and 1000 µmol L-1 with a limit of detection of 0.4 µmol L-1 and a sensitivity of 2873 µA mmol-1 L cm-2. The applicability of here reported Ni-NPs/Ppy(1)/GRE-based sensor has been demonstrated by the determination of glucose concentrations in real samples.
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Electrochemical Deposition and Investigation of Poly-9,10-Phenanthrenequinone Layer.
Nanomaterials, 2019Co-Authors: Povilas Genys, Elif Aksun, Almira Ramanaviciene, Aušra Valiūnienė, Alla Tereshchenko, Arunas RamanaviciusAbstract:In this research, a 9,10-phenanthrenequinone (PQ) was electrochemically polymerized on a Graphite Rod electRode using potential cycling. The electRode modified by poly-9,10-phenanthrenequinone (poly-PQ) was studied by means of cyclic voltammetry, electrochemical impedance spectroscopy, atomic force microscopy and scanning electron microscopy. The poly-PQ shows variations in growth pattern depending on the number of potential cycles for the initiation of polymerization. Formed poly-PQ layer demonstrates good electric conductivity, great degree of electrochemical capacitance and unique oxidation/reduction properties, which are suitable for broad technological applications, including applicability in biosensors, supercapacitors and in some other electrochemical systems.
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Electrochemical Formation and Evaluation of Poly-9,10-Phenanthrenequinone of Layer
2018Co-Authors: Arunas Ramanavicius, Povilas Genys, Elif Aksun, Aušra Valiūnienė, Almira RamanavicieneAbstract:A 9,10-phenanthrenequinone (PQ) was electrochemically polymerized on a Graphite Rod electRode using potential cycling. The electRode modified by poly-9,10-phenanthrenequinone (poly-PQ) was studied by means of cyclic voltammetry, electrochemical impedance spectroscopy, atomic force microscopy and scanning electron microscopy. The poly-PQ shows variations in growth pattern depending on the number of potential cycles for the initiation of polymerization. Formed poly-PQ layer demonstrates good electric conductivity, great electrochemical capacitance and unique oxidation/reduction properties, which are suitable for broad technological applications, including applicability in biosensors, supercapacitors, and in some other electrochemical systems.
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Reagent-less amperometric glucose biosensor based on a Graphite Rod electRode layer-by-layer modified with 1,10-phenanthroline-5,6-dione and glucose oxidase.
Talanta, 2017Co-Authors: Asta Kausaite-minkstimiene, Almira Ramanaviciene, Ruta Simanaityte, Laura Glumbokaite, Arunas RamanaviciusAbstract:Abstract A reagent-less amperometric glucose biosensor operating in not-stirred sample solution was developed. A working electRode of the designed biosensor was based on a Graphite Rod (GR) electRode, which was modified with 1,10-phenanthroline-5,6-dione (PD) and glucose oxidase (GOx). The PD and the GOx were layer-by-layer adsorbed on the GR electRode surface with subsequent drying followed by chemical cross-linking of the adsorbed GOx with glutaraldehyde (GA). Optimal preparation conditions of the working electRode (GR/PD/GOx) were achieved with 12.6 μg and 0.24 mg loading amount of PD and GOx, respectively and 25 min lasting cross-linking of the GOx with GA. A current response to glucose of the GR/PD/GOx electRode was measured at +200 mV potential vs Ag/AgCl reference electRode. Maximum current response was registered when the pH of the buffer solution was 6.0. The registered current response to glucose was linear in the concentration range of 0.1–76 mmol L –1 (R 2 =0.9985) and a detection limit was 0.025 mmol L –1 . The GR/PD/GOx electRode demonstrated good repRoducibility and repeatability with the relative standard deviation of 6.2% and 1.8% (at 4.0 mmol L –1 of glucose), respectively, high anti-interference ability to uric and ascorbic acids. It was highly selective to glucose and demonstrated good accuracy in the analysis of human serum samples.
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Development of poly(3-aminophenylboronic acid) modified Graphite Rod electRode suitable for fluoride determination
Talanta, 2014Co-Authors: Hakan Çiftçi, Yasemin Oztekin, Ugur Tamer, Almira Ramanavicine, Arunas RamanaviciusAbstract:Poly(3-aminophenylboronic acid), (PAPBA) film was formed on the Graphite Rod surface by potential cycling. The PAPBA-modified Graphite Rod (PAPBA/GR) electRode prepared in this way was used for potentiometric fluoride determination. The linear calibration range was from 5×10(-4) to 5×10(-2)M with the slope of the linear part of the calibration curve of 42.5mV/logC. No interference effect of the most common ions such as sodium, potassium, chloride, nitrate, iodide, calcium, zinc, aluminum, sulfate and sorbitol was observed during electrochemical determination of fluoride. On the other hand, the PAPBA/GR electRode showed not only good sensitivity and selectivity, but also relatively rapid response to changes of analyte concentrations in the range of 20s. The sensor was successfully applied for fluoride determination in real sample - toothpaste.
In-hwan Lee - One of the best experts on this subject based on the ideXlab platform.
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Hydrothermal growth of single crystal ZnO nanoRods on surface-modified Graphite
Electronic Materials Letters, 2013Co-Authors: Trilochan Sahoo, Lee-woon Jang, Dae-woo Jeon, In-hwan LeeAbstract:ZnO nanostructures were hydrothermally grown at 90°C on bare and surface-modified Graphite. Thermodynamically active sites along the grain boundaries on the Graphite surface initiated scattered nucleation of ZnO, leading to the formation of a bunched structure. The uniformity of nucleation and the size distribution of nanoRods were controlled by modifying the Graphite surface with a seed layer. The seed layer was created on the Graphite Rod by coating it with ethanolic solution of zinc acetate followed by baking at 300°C. The preformed particles on this layer acted as nucleation center for subsequent growth of ZnO nanoRods. The resulting ZnO nanoRods were vertically well-aligned single crystals, exhibiting strong band edge luminescence.
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Growth of ZnO nanostructures on Graphite-Rod by hydrothermal technique
2012Co-Authors: Trilochan Sahoo, In-hwan LeeAbstract:Growth of ZnO on Graphite Rods by low temperature hydrothermal technique is described. ZnO nanostructures were grown at 90°C in an aqueous precursor on bare and seeded Graphite. Thermodynamically active sites along the grain boundaries on Graphite surface initiated scattered nucleation of ZnO leading to the formation of a bunched structure. The uniformity of nucleation and of nanoRod size distribution could be achieved by modifying the Graphite surface with a seed layer. Electron microscopy demonstrated that closely packed nanoRods were formed nearly normal to the surface of the Graphite Rod. ZnO nanoRods having fairly uniform diameter and length were grown that way. X-ray diffraction and electron microscopy revealed that the ZnO nanoRods were single crystal, and oriented along the c-axis. The as grown ZnO nanoRods exhibited strong band edge luminescence and weak deep level emissions.
Shaoqi Peng - One of the best experts on this subject based on the ideXlab platform.
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The effect of different kinds of inert gases and their pressures on the preparation of carbon nanotubes by carbon arc method
Materials Chemistry and Physics, 1999Co-Authors: Haiyan Zhang, Xinmin Xue, Dengyu Wang, Shaoqi PengAbstract:Abstract The preparation of carbon nanotubes in argon atmosphere was compared with that in helium atmosphere by carbon arc method at a pressure ranging from 80 to 680 Torr. The investigations of preparation conditions, the rate of Graphite Rod consumption, the growth rates of cathode deposits and the efficiency of converting consumed Graphite into deposits in different inerts and their pressure have been carried out. The effect of Ar atmosphere and He atmosphere on the preparation of nanotubes and C60/70 are compared. The diameter distributions of nanotubes pRoduced in Ar and He gas are also examined by TEM observation. Oxidation process under the same conditions show that the sample prepared in Ar atmosphere has fewer nanoparticles and more nanotubes than those prepared in He atmosphere.
Noritsugu Umehara - One of the best experts on this subject based on the ideXlab platform.
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Extension of surface-wave-excited high-density plasma column sustained along Graphite Rod target
Vacuum, 2006Co-Authors: Hiroyuki Kousaka, Noritsugu UmeharaAbstract:Abstract In typical, surface-wave-excited plasma (SWP) is generated along dielectric antennas such as a quartz tube or an alumina disk to guide surface waves. However, recently, we intRoduced a new SWP sustained along the surface of a metal antenna at a negative voltage against a grounded chamber. In this work, Ar plasma was generated along a Graphite Rod (10 mm in diameter and 190 mm in length) at a background gas pressure of 5.7 Pa with an incident microwave power of 200 W and a negative voltage Vt supplied to the Rod. At V t = 0 V , overdense SWP was sustained locally at around the one end of the Graphite Rod. The plasma was then confirmed to extend longer along the Rod axis, with increasing Vt. At V t = – 2 0 0 V , the plasma showed a columnar structure with an electron density larger than 1011 cm−3. Note that the SWP column obtained strongly sputtered the Graphite Rod; thus, we considered that a new sputtering source can be developed employing this new technique, or SWPs sustained along metal targets.
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Pressure dependence of surface wave-excited plasma column sustained along metal Rod antenna
Vacuum, 2006Co-Authors: Hiroyuki Kousaka, Noritsugu UmeharaAbstract:Abstract A novel method was proposed to generate high-density microwave-excited plasma along metal surfaces. In our previous work, 2.45 GHz microwaves were confirmed to propagate as surface waves along the interface between overdense (>10 11 cm –3 ) plasma and a Graphite Rod biased at a negative voltage against a grounded chamber. The generated plasma showed columnar structure surrounding the Rod surface, and thus it was called metal-antenna surface wave-excited plasma (MASWP) column. In this work, the effect of gas pressure on the spatial distribution of MASWP column was investigated. It was confirmed that the length of MASWP column became longer along a Graphite Rod (25 cm in length and 1 cm in diameter) with increasing gas pressure. In particular, at an Ar gas pressure of 33 Pa, we obtained a long plasma column covering the entire surface of the Rod with a negative voltage of −150 V and an input microwave power of 100 W. The same tendency, or the extension of MASWP column with increasing gas pressure was also confirmed by using a copper Rod and a stainless-steel Rod instead of the Graphite Rod. This indicates that the extension of MASWP column with increasing gas pressure occurs independently of antenna materials.
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Microwave-Excited High-Density Plasma Column Sustained along Metal Rod at Negative Voltage
Japanese Journal of Applied Physics, 2005Co-Authors: Hiroyuki Kousaka, Noritsugu Umehara, Kouichi OnoAbstract:We have studied the mechanism of a microwave-excited plasma column sustained along a Graphite Rod at a negative voltage. It was confirmed that an Ar plasma column is extended longer along the Rod axis by increasing the negative voltage. Langmuir probe measurement showed that the electron density was higher than 1011 cm-3 at a gas pressure of 4.5 Pa with an incident microwave power of 200 W and a negative voltage of -240 V. Significantly localized electromagnetic fields were detected near the Rod surface, indicating that surface waves propagated along the axis of the conductive (or nondielectric) Graphite Rod.
