Refine your search:     
Report No.
 - 
Search Results: Records 1-12 displayed on this page of 12
  • 1

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Highly sensitive detection of sodium in aqueous solutions using laser-induced breakdown spectroscopy with liquid sheet jets

Nakanishi, Ryuzo; Oba, Hironori; Saeki, Morihisa; Wakaida, Ikuo; Tanabe, Rie*; Ito, Yoshiro*

Optics Express (Internet), 29(4), p.5205 - 5212, 2021/02

 Times Cited Count:0 Percentile:0(Optics)

Laser-induced breakdown spectroscopy (LIBS) combined with liquid jets was applied to the detection of trace sodium (Na) in aqueous solutions. The sensitivities of two types of liquid jets were compared: a liquid cylindrical jet with a diameter of 500 $$mu$$m and a liquid sheet jet with a thickness of 20 $$mu$$m. Compared with the cylindrical jet, the liquid sheet jet effectively reduced the splash from the laser-irradiated surface and produced long-lived luminous plasma. The limit of detection (LOD) of Na was determined to be 0.57 $$mu$$g/L for the sheet jet and 10.5 $$mu$$g/L for the cylindrical jet. The LOD obtained for the sheet jet was comparable to those obtained for commercially available inductively coupled plasma emission spectrometers.

Journal Articles

Application of an augmentation method to MCR-ALS analysis for XAFS and Raman data matrices in the structural change of isopolymolybdates

Saeki, Morihisa*; Yomogida, Takumi; Matsumura, Daiju; Saito, Takumi*; Nakanishi, Ryuzo*; Tsuji, Takuya; Oba, Hironori*

Analytical Sciences, 36(11), p.1371 - 1378, 2020/11

 Times Cited Count:0 Percentile:0(Chemistry, Analytical)

We measured X-ray absorption fine structure (XAFS) and Raman spectra of isopolymolybdates(VI) in HNO$$_{3}$$ solution (0.15- 4.0 M), which change their geometries depending on acid concentration, and performed simultaneous resolution of the XAFS and Raman data using a multivariate curve resolution by alternating least-squares (MCR-ALS) analysis. In iterative ALS optimization, initial data matrices were prepared by two different methods. The MCR-ALS result of single XAFS data matrix shows large dependence on the preparation method of the initial data matrices. The MCR-ALS result of an augmented matrix of Raman and XAFS data has little dependence on the initial data matrices. It indicates that the augmentation method effectively improves the rotation ambiguities in the MCR-ALS analysis of the XAFS data. Based on the model fitting of the pure EXAFS oscillations, we revealed the change of [Mo$$_{36}$$O$$_{112}$$(H$$_{2}$$O)$$_{16}$$]$$^{2+}$$ $$rightarrow $$ [Mo$$_{2}$$O$$_{5}$$(H$$_{2}$$O)$$_{6}$$]$$^{2+}$$ $$rightarrow $$ [HMoO$$_{3}$$(H$$_{2}$$O)$$_{3}$$]$$^{+}$$ in the highly concentrated HNO$$_{3}$$ solution.

Oral presentation

Speciation of isopolymolybdate(VI) in a highly concentrated HNO$$_{3}$$ solution by Raman and EXAFS spectroscopies

Saeki, Morihisa*; Yomogida, Takumi; Matsumura, Daiju; Saito, Takumi*; Nakanishi, Ryuzo*; Tsuji, Takuya; Okamoto, Yoshihiro; Oba, Hironori*

no journal, , 

Speciation of isopolymolybdates in a highly concentrated HNO$$_{3}$$ solution was investigated by Raman spectroscopy and Mo K-edge extended X-ray absorption fine structure (EXAFS). A series of Raman spectra and EXAFS oscillations were analyzed using Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS). The MCR-ALS analysis gives us the fraction profile in change of [Mo$$_{36}$$O$$_{112}$$(H$$_{2}$$O)$$_{16}$$]$$^{8-}$$$$rightarrow$$[Mo$$_{2}$$O$$_{5}$$]$$^{2+}$$$$rightarrow$$[MoO$$_{2}$$]$$^{2+}$$ with the increase of the HNO$$_{3}$$ concentration.

Oral presentation

In Situ Time-Resolved XAFS Studies on Laser-Induced Particle Formation of Platinum Groups Metal Ions in a H$$_{2}$$O / EtOH Solution

Saeki, Morihisa*; Matsumura, Daiju; Yomogida, Takumi; Taguchi, Tomitsugu*; Tsuji, Takuya; Saito, Hiroyuki*; Nakanishi, Ryuzo*; Oba, Hironori*

no journal, , 

When nanosecond pulsed UV laser is irradiated into a H$$_{2}$$O / EtOH solution of platinum group metal (PGM) ions, PGM particles with sub-micron size are formed. We investigated laser induced particle formation of Pd$$^{2+}$$ in the H$$_{2}$$O / EtOH solution by in situ time-resolved XAFS spectroscopy and showed dependence of the reaction rate of laser-induced particle formation on the laser fluence. The dependence on the laser fluence elucidated that the photons contribute not only to the reduction of the Pd$$^{2+}$$, but also to the autocatalytic growth of the Pd particles.

Oral presentation

In situ time-resolved XAFS studies on photo-induced particle formation in an aqueous/ethanol solution of PdCl$$_{4}$$$$^{2-}$$ using ns pulsed UV laser; Dependence of chemical kinetics on laser pulse energy

Saeki, Morihisa*; Yomogida, Takumi; Matsumura, Daiju; Nakanishi, Ryuzo*; Taguchi, Tomitsugu*; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*

no journal, , 

In the absence of a photoactivator, the laser-induced particle formation in an H$$_{2}$$O/ EtOH solution of PdCl$$_{4}$$$$^{2-}$$ was performed by three kinds of irradiation condition using fourth harmonics of the pulsed UV laser (266 nm). In the irradiation, pulsed laser energy was arranged to 5, 10 and 25 mJ, where average laser power is kept to 250 mW. The reaction kinetics of the laser-induced particle formation was observed using dispersive XAFS measurement. About half of Pd ions were reduced with 5 mJ pulsed laser irradiation. In contrast, all Pd ions were reduced with 25 mJ pulsed laser irradiation. The result elucidates that the laser photon contributes to the generation of Pd metals by the multi-photon process.

Oral presentation

Practical application of LIBS and rerated spectroscopy for decommissioning work of Fukushima Daiichi Nuclear Power Station

Wakaida, Ikuo; Oba, Hironori; Miyabe, Masabumi; Akaoka, Katsuaki; Oba, Masaki; Tamura, Koji; Saeki, Morihisa; Nakanishi, Ryuzo; Ikeda, Yuji*; Sakka, Tetsuo*; et al.

no journal, , 

no abstracts in English

Oral presentation

Gamma-ray irradiation effects to the laser-induced breakdown spectroscopy system using a ceramic and a single crystal micro-laser

Tamura, Koji; Nakanishi, Ryuzo; Oba, Hironori; Saeki, Morihisa; Taguchi, Tomitsugu*; Lim, H. H.*; Taira, Takunori*; Wakaida, Ikuo

no journal, , 

Oral presentation

Rare earth elements detection in mixed oxide using a fiber optic LIBS with a ceramic micro-laser

Oba, Hironori; Tamura, Koji; Nakanishi, Ryuzo; Saeki, Morihisa; Lim, H. H.*; Taira, Takunori*; Wakaida, Ikuo

no journal, , 

Oral presentation

Development on laser remote analysis for on-site, in-situ and quick screening of nuclear fuel debris in decommissioning of Fukushima Daiichi Nuclear Power Station

Wakaida, Ikuo; Oba, Hironori; Miyabe, Masabumi; Akaoka, Katsuaki; Oba, Masaki; Tamura, Koji; Saeki, Morihisa; Nakanishi, Ryuzo; Ikeda, Yuji*; Sakka, Tetsuo*; et al.

no journal, , 

Oral presentation

DXAFS study on laser-induced photoreduction mechanism of Rh$$^{III}$$ ion complexes; Extraction of intermediates information by multivariate spectral analysis

Saeki, Morihisa*; Matsumura, Daiju; Nakanishi, Ryuzo*; Yomogida, Takumi; Tsuji, Takuya; Saito, Hiroyuki*; Oba, Hironori*

no journal, , 

The precious metal (PM) ions complexed with negative ions and water molecules in solution has a charge transfer absorption band in the UV region. When alcohol is added to such a PM$$^{n+}$$ complex solution and irradiated with an ultraviolet laser, the PM$$^{n+}$$ complex is electronically excited and reacts with the alcohol to be reduced to the neutral atom PM$$^{0}$$. The reduced PM$$^{0}$$ spontaneously aggregates in the solution to form fine particles. This process is called Laser-Induced Particle Formation (LIPF), and is used for the formation of precious metal nanoparticles and the recovery of precious metals from factory effluents. We have investigated the LIPF reaction mechanism of Rh$$^{3+}$$ ion complexes by in situ energy-dispersive X-ray absorption fine structure spectroscopy(XAFS). As a result of analyzing the obtained XAFS spectra, we found that Rh species with three oxidation numbers are involved in the Rh$$^{3+}$$reduction reaction, which proceeds from Rh$$^{3+}$$ to Rh$$^{int}$$ (intermediate) to Rh$$^{0}$$.

Oral presentation

Oral presentation

Laser remote analysis for decommissioning of Fukushima Daiichi Nuclear Power Station

Wakaida, Ikuo; Oba, Hironori; Akaoka, Katsuaki; Shibata, Takuya; Nakanishi, Ryuzo; Karino, Takahiro

no journal, , 

no abstracts in English

12 (Records 1-12 displayed on this page)
  • 1