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21.
Fundamental properties of a touchable high‐power pulsed microplasma jet and its application as a desorption/ionization source for ambient mass spectrometry 下载免费PDF全文
Takahiro Iwai Ken Kakegawa Kensuke Okumura Mieko Kanamori‐Kataoka Hidekazu Miyahara Yasuo Seto Akitoshi Okino 《Journal of mass spectrometry : JMS》2014,49(6):522-528
Plasma‐based ambient desorption/ionization mass spectrometry (ADI–MS) has attracted considerable attention in many fields because of its capacity for direct sample analyses. In this study, a high‐power pulsed microplasma jet (HPPMJ) was developed and investigated as a new plasma desorption/ionization source. In an HPPMJ, a microhollow cathode discharge is generated in a small hole (500 µm in diameter) using a pulsed high‐power supply. This system can realize a maximum power density of 5 × 108 W/cm3. The measured electron number density, excitation temperature and afterglow gas temperature of the HPPMJ were 3.7 × 1015 cm‐3, 7000 K at maximum and less than 60 °C, respectively, which demonstrate that the HPPMJ is a high‐energy, high‐density plasma source that is comparable with an argon inductively coupled plasma while maintaining a low gas temperature. The HPPMJ causes no observable damage to the target because of its low gas temperature and electrode configuration; thus, we can apply it directly to human skin. To demonstrate the analytical capacity of ADI–MS using an HPPMJ, the plasma was applied to direct solid sample analysis of the active ingredients in pharmaceutical tablets. Caffeine, acetaminophen, ethenzamide, isopropylantipyrine and ibuprofen were successfully detected. Application to living tissue was also demonstrated, and isopropylantipyrine on a finger was successfully analyzed without damaging the skin. The limits of detection (LODs) for caffeine, isopropylantipyrine and ethenzamide were calculated, and LODs at the picogram level were achieved. These results indicate the applicability of the HPPMJ for high‐sensitivity analysis of materials on a heat‐sensitive surface. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Nickel phosphide particles were synthesized by thermal decomposition of a nickel precursor in a mixed solution of trioctylphosphine and trioctylphosphine oxide. The crystal phase and morphology of samples prepared by changing the solvents, the amount of trioctylphosphine as a phosphorus source, the reaction temperature, and the nickel precursor were characterized using X-ray diffraction and transmission electron microscopy. Spherical Ni(5)P(4) particles with diameters of 500 nm were obtained using nickel acetylacetonate as a nickel precursor at 360 °C for 1 h in trioctylphosphine oxide. NiP(2) particles with diameters of 200-500 nm were obtained using nickel acetate tetrahydrate at 360 °C for 5 h in trioctylphosphine oxide. All-solid-state cells were fabricated using NiP(2) particles as an active material and 80Li(2)S·20P(2)S(5) (mol %) glass-ceramic as a solid electrolyte. The Li-In/80Li(2)S·20P(2)S(5)/NiP(2) cell exhibited an initial discharge capacity of 1100 mAh g(-1) at a current density of 0.13 mA cm(-2) and retained a discharge capacity of 750 mAh g(-1) after 10 cycles. 相似文献
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Wide-bore capillary hydrodynamic chromatography (W-HDC) resolves analytes on the basis of a difference in the extent of radial diffusion simply by their passage through an empty capillary. The combination of this method with ICP-MS proves efficient for the evaluation of the interaction of metal ions with molecular aggregates. Lecithin vesicles are suitable molecular aggregates for the uptake of the lanthanide ions in the presence of the first row transition metal ions, suggesting that the present method is applicable to the screening of the molecular aggregate system suitable for selective extraction of a particular targeted small molecule. The visual inspection of the elution profiles gives us qualitative but useful information on the interaction between the vesicle and metal ions. In addition, studying the slope of the front edge of an elution curve provides more quantitative implications. 相似文献
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Akitoshi Hayashi Hideki MorishimaKiyoharu Tadanaga Masahiro Tatsumisago 《Solid State Ionics》2011,192(1):126-129
Glassy solid electrolytes were prepared by combining the 50Li2SO4·50Li3BO3 (mol%) ionic glass and the 1-ethyl-3-methyl-imidazolium tetrafluoroborate ([EMI]BF4) ionic liquid. High-energy ball milling was carried out for the mixture of the inorganic ionic glass and the organic ionic liquid. The ambient temperature conductivity of the glass electrolyte with 10 mol% [EMI]BF4 was 10−4 S cm−1, which was three orders of magnitude higher than that of the 50Li2SO4·50Li3BO3 glass. The addition of [EMI]BF4 to the ionic glass decreased glass transition temperature (Tg) of the glass and the decrease of Tg is closely related to the enhancement of conductivity of the glass. Morphology and local structure of the glass electrolyte was characterized. The dissolution of an ionic liquid in an ionic glass with Li+ ion conductivity is a novel way to developing glass electrolytes for all-solid-state lithium secondary batteries. 相似文献
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Takamasa Ohtomo Akitoshi Hayashi Masahiro Tatsumisago Koji Kawamoto 《Journal of Solid State Electrochemistry》2013,17(10):2551-2557
Sulfide solid electrolytes, which show high ion conductivity, are anticipated for use as electrolyte materials for all-solid-state batteries. One drawback of sulfide solid electrolytes is their low chemical stability in air. They are hydrolyzed by moisture and generate H2S gas. Substituting oxygen atoms for sulfur atoms in sulfide solid electrolytes is effective for suppression of H2S gas generation in air. Especially, the xLi2O·(75-x)Li2S·25P2S5 (mol%) glasses hardly generated H2S gas in air. However, substituting oxygen atoms for sulfur atoms caused a decrease in conductivity. The x?=?7 glass showed high chemical stability in air and maintained high conductivity of 2.5?×?10?4 S cm?1 at room temperature. Performance of cells using the 7Li2O·68Li2S·25P2S5 and the 75Li2S·25P2S5 glasses as solid electrolytes were compared. All-solid-state C/LiCoO2 cell using the 7Li2O·68Li2S·25P2S5 glass produced performance as good as that obtained using the 75Li2S·25P2S5 glass. Capacity retention and change of interfacial resistance of the former cell were superior to those of the latter cell after storage at 4.0 V and 60 °C. The diffusion of oxygen element into the 7Li2O·68Li2S·25P2S5 glass was less than that into the 75Li2S·25P2S5 glass after storage at the voltage of 4.0 V at 60 °C. Improvement of the stability of sulfide solid electrolytes to moisture was related to cell performance as well as an increase in conductivity. 相似文献
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Satoshi Ujiie Akitoshi Hayashi Masahiro Tatsumisago 《Journal of Solid State Electrochemistry》2013,17(3):675-680
The glass–ceramic electrolytes of (100?x)(0.8Li2S·0.2P2S5)·xLiI (in mole percent; x?=?0, 2, 5, 10, 15, 20, and 30) were prepared by mechanical milling and subsequent heat treatment. Crystalline phases analogous to the thio-LISICON region II or III in the Li2S–GeS2–P2S5 system were precipitated. The thio-LISICON III analog phase was mainly precipitated at the composition x?=?0, and the thio-LISICON II analog phase was precipitated in the composition range from x?=?2 to 15. The X-ray diffraction peaks of the thio-LISICON II analog phase shifted to the lower diffraction angle side with increasing the LiI content. High conductivities above 2?×?10?3?S?cm?1 at room temperature were observed in the glass–ceramics at the wide composition range from x?=?2 to 15. The glass–ceramic electrolyte at x?=?5 with the highest conductivity of 2.7?×?10?3?S?cm?1 showed a wide electrochemical window of about 10 V. The addition of LiI to the 80Li2S·20P2S5 (in mole percent) glass was effective in crystallizing the thio-LISICON II analog phase with high conductivity from the glass. 相似文献
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Kitaguchi Y Shiotari A Okuyama H Hatta S Aruga T 《The Journal of chemical physics》2011,134(17):174703
Adsorption of methanol and its dehydrogenation on Cu(110) were studied by using a scanning tunneling microscope (STM). Upon adsorption at 12 K, methanol preferentially forms clusters on the surface. The STM could induce dehydrogenation of methanol sequentially to methoxy and formaldehyde. This enabled us to study the binding structures of these products in a single-molecule limit. Methoxy was imaged as a pair of protrusion and depression along the [001] direction. This feature is fully consistent with the previous result that it adsorbs on the short-bridge site with the C-O axis tilted along the [001] direction. The axis was induced to flip back and forth by vibrational excitations with the STM. Two configurations were observed for formaldehyde, whose structures were proposed based on their characteristic images and motions. 相似文献
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Takuya Matsuyama Atsushi Sakuda Akitoshi Hayashi Yoshihiko Togawa Shigeo Mori Masahiro Tatsumisago 《Journal of Solid State Electrochemistry》2013,17(10):2697-2701
Amorphous titanium trisulfide (TiS3) active materials were prepared by ball milling of an equimolar mixture of crystalline titanium disulfide (TiS2) and sulfur. A high-resolution transmission electron microscope image revealed no periodic lattice fringes on the amorphous TiS3. The all-solid-state lithium secondary batteries using a sulfide solid electrolyte and the amorphous TiS3 electrode showed high capacity of greater than 300 mAh g?1 for 10 cycles. The amorphous TiS3 had a higher capacity than the mixture of crystalline TiS2 and S, which was used as the starting material of amorphous TiS3. The X-ray diffraction patterns and the Raman spectra of the amorphous TiS3 electrode after the first and tenth charge–discharge measurements were similar to those before the measurement. The amorphous structure of TiS3 did not change greatly during the first few cycles. The all-solid-state cells with the amorphous TiS3 electrode showed higher initial coulombic efficiency because the amorphous TiS3 active material retained its structure during the initial electrochemical test. 相似文献
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Iwai Takahiro Inoue Hiroki Kakegawa Ken Ohrui Yasuhiko Nagoya Tomoki Nagashima Hisayuki Miyahara Hidekazu Chiba Koichi Seto Yasuo Okino Akitoshi 《Plasma Chemistry and Plasma Processing》2020,40(4):907-920
Plasma Chemistry and Plasma Processing - High-efficiency decomposition technology for volatile chemical warfare agent sarin was developed using a dielectric-barrier discharge (DBD). The power... 相似文献