著者

Motoki Shiga Shunsuke Muto

出版者

The Japan Society of Vacuum and Surface Science

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.17, pp.148-154, 2019-09-21 (Released:2019-09-21)

参考文献数

19

被引用文献数

7

---

Scanning transmission electron microscopy combined with electron energy-loss spectroscopy and energy-dispersive X-ray spectroscopy is useful for analyzing chemical states and elemental components in a new material. Using these instruments, the spectra over the spatial grid points in a region of interest can be observed. This measurement technique is called spectral imaging (SI). Because of the large size of SI data, the analysis cost is a bottleneck in the evaluation process of the material. To reduce the analysis cost, machine learning techniques can be applied, which can automatically extract essential information from the data. This paper reviews our developed machine learning method, which is based on non-negative matrix factorization and its extensions. A spatial orthogonality constraint and a generalized noise model, which includes Gaussian and Poisson noise models, are introduced. Numerical experiments demonstrate the effectiveness and characteristics of our developed methods.

著者

Hiroshi Kuwahata Takeshi Yamaguchi

出版者

The Japan Society of Vacuum and Surface Science

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.14, pp.231-236, 2016-12-24 (Released:2016-12-24)

参考文献数

25

被引用文献数

1 3

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An atmospheric-pressure argon (Ar) plasma jet was generated with a frequency of 10 kHz, an applied voltage of 10 kV, and an Ar gas flow rate of 10 L/min. When an aluminum (Al) thin film deposited on a glass substrate was irradiated with the Ar plasma jet in air for 5 s, Al was removed. The removal rate was ∼700 nm/s. Because the streamers in the plasma reached the Al thin film, Al was removed and a mark was formed on the film, which was referred to as a removal mark. The shape of the removal mark depended on the irradiation distance: it was ring-shaped with an inner diameter of ∼5 mm and an outer diameter of ∼6 mm for irradiation distances of 2–7 mm, and disc-shaped with a diameter of ∼5 mm for irradiation distances of 10–20 mm. The dependence of the shape of the removal mark on the irradiation distance suggests that the distribution of the streamers in the plasma depended on the irradiation distance. The streamers inside the quartz tube were concentrated along the inner wall. In contrast, the streamers outside the tube were distributed in a ring shape with an inner diameter of ∼5 mm and an outer diameter of ∼6 mm for irradiation distances of 2–7 mm, but they converged then diverged to form a smaller disc shape with a diameter of ∼5 mm for irradiation distances of 10–20 mm. [DOI: 10.1380/ejssnt.2016.231]

著者

Hikaru Sawahata Naoya Yamaguchi Hiroki Kotaka Fumiyuki Ishii

出版者

The Japan Society of Vacuum and Surface Science

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.16, pp.427-430, 2018-11-24 (Released:2018-11-24)

参考文献数

29

被引用文献数

1

---

We investigate the effect of the electric field on the edge states in one-bilayer Bi(111) by first-principles calculations. We calculate the band structures of armchair and zigzag Bi nanoribbons. With increasing strength of the electric field E > 2.1 V/Å, the armchair nanoribbon shows a topological phase transition from non-trivial metallic edge states to insulating edge states. However, under the same conditions, the zigzag nanoribbon shows a topological phase transition from non-trivial metallic edge states to trivial metallic edge states. We expect that these findings will contribute to the development of, e.g., spin current switches for use in next-generation devices. [DOI: 10.1380/ejssnt.2018.427]

著者

S. Kobayashi S. Kaneko S. Fujii T. Nishino M. Kiguchi K. Tsukagoshi

出版者

The Japan Society of Vacuum and Surface Science

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.16, pp.145-149, 2018-05-12 (Released:2018-05-12)

参考文献数

34

被引用文献数

2

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We have investigated the current-voltage (I-V) curves of the benzenedithiol (BDT) single molecular junction as a function of stretch length of the junction. The BDT single molecular junction was prepared with the nano fabricated Au electrodes using the mechanically controllable break junction (MCBJ). The conductance of the BDT single molecular junction gradually decreased with the stretching length of the junction. We analyzed the obtained I-V curves based on the two different models; the single channel model and the field emission model. Based on the single channel model, it was revealed that the decrease in conductance was mainly caused by the decreases in the metal-molecule coupling and that the HOMO approached to the Fermi level with the decrease in the electrode separation. The energy shift of the HOMO was supported by the analysis based on the field emission model. [DOI: 10.1380/ejssnt.2018.145]

著者

Natee Sirisit Daiki Kido Yuki Wakisaka Hiroko Ariga-Miwa Satoru Takakusagi Kiyotaka Asakura Oki Sekizawa Tomohiro Sakata Tomoya Uruga Yasuhiro Iwasawa

出版者

The Japan Society of Vacuum and Surface Science

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.16, pp.387-390, 2018-09-01 (Released:2018-09-01)

参考文献数

20

被引用文献数

3

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We have shown a possibility of multi-atom resonant X-ray Raman (MARX-Raman) spectroscopy by measuring the N K-edge loss spectrum of TaN at Ta L3-edge and C K-edge loss spectrum of Er(C5H5)3 at Er L1-edge. When the excitation X-ray energy was tuned to the Ta L3-edge and inelastic scattering spectra were recorded around 400 eV loss corresponding to the N K-edge Raman region, we found a clear enhancement of emission spectrum. The same enhancement was observed in C K-edge Raman region in Er(C5H5)3. These experimental results have indicated the possibility of MARX-Raman phenomenon which may lead to a new in situ and bond-specific XAFS spectroscopy for low Z elements. [DOI: 10.1380/ejssnt.2018.387]

著者

Theodore L. Einstein Ludwig Bartels Josue R. Morales-Cifuentes

出版者

The Japan Society of Vacuum and Surface Science

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.16, pp.201-208, 2018-05-25 (Released:2018-05-25)

参考文献数

70

被引用文献数

1

---

This paper modestly expands an invited talk at ISSS-8 with the same title. After reviewing the relevant interactions between adsorbates on substrates with metallic surface states [especially Cu(111)], it focuses on organic adsorbates. Of particular interest are those which form honeycomb lattices with pores of various sizes. The nature of the confined states derived from the surface-state electrons is discussed as their effect on admolecules inside the pores. [DOI: 10.1380/ejssnt.2018.201]

著者

Tsuyoshi Akiyama

出版者

The Surface Science Society of Japan

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.10, pp.157-160, 2012-04-27 (Released:2012-04-27)

参考文献数

28

被引用文献数

1 6

---

I have fabricated gold and silver nanoparticle layers on amino-terminated glass substrates by immersion processes from aqueous colloidal solutions of gold and silver nanoparticles. The composition ratio of nanoparticles on the modified substrates was varied by the mixing ratio of corresponding colloidal solutions of nanoparticles. Raman signals of rhodamine 6G were observed on the nanoparticle-modified substrates. In the case of the mixed gold and silver nanoparticle-modified substrates, the intensities of the Raman signals were larger than the intensities expected from a simple proportional sum of the Raman signals obtained using a gold nanoparticle layer or a silver nanoparticle layer. The nonlinear enhancement properties of the Raman signal intensities may be attributable to unique localized surface plasmon resonance between the gold and silver nanoparticles. [DOI: 10.1380/ejssnt.2012.157]

著者

Seyedeh Maryamdokht Taimoory John F. Trant Abbas Rahdar Mousa Aliahmad Fardin Sadeghfar Mahmoud Hashemzaei

出版者

公益社団法人 日本表面科学会

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.15, pp.31-39, 2017-04-01 (Released:2017-04-03)

参考文献数

88

被引用文献数

24

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Magnetite (Fe3O4) nanoparticles, are promising inorganic nanomaterials for future biomedical applications due to their low toxicity and unique magnetic properties. However, the synthesis of these particles can often be expensive, energy intensive, and non-scalable, requiring the addition of surfactants to stabilize the material to control the particle size and avoid agglomeration. We wish to report a simple, green, surfactant-free electrochemical synthesis of these materials using a closed aqueous system at ambient temperature. Particle diameter, between 19 and 33 nm, was controlled by simply modifying the distance between the electrodes. These magnetite nanoparticles were then fully characterized using both spectroscopy and microscopy. Vibrational magnetometry indicates that as the size of the particle decreases, the magnetic hysteretic gap decreases, although for samples below 25 nm no inter-sample difference was observed. To support this experimental data, we carried out a Density Functional Theory (DFT) analysis of magnetite containing more than three iron atoms in the cluster, an essential proposition as magnetite contains three distinct iron species. These calculations were used to support the experimental observations, and closely reproduced both the experimental IR spectrum, and the XRD pattern. In vitro cytotoxicity assays showed dose responsive behavior for the nanoparticles, and demonstrated that they are non-toxic at clinically relevant concentrations; below 200 μg/mL we observed no toxicity in a 48-hour standard assay. This work represents the first DFT based simulation of this detailed magnetite cluster, and demonstrates that this sustainable synthetic method is capable of producing nanomaterials with a physical and biological profile that might make them suitable for biomedical applications. [DOI: 10.1380/ejssnt.2017.31]

著者

Tomohiro Shiraki Naotoshi Nakashima

出版者

公益社団法人 日本表面科学会

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.13, pp.179-184, 2015-04-18 (Released:2015-04-18)

参考文献数

75

被引用文献数

1

---

The determination of electronic states of single-walled carbon nanotubes (SWNTs) has been a central issue in nanoscience of carbon nanotubes. We have established an in situ photoluminescence (PL) spectroelectrochemistry to determine the electronic properties of the SWNTs. This review article focuses on the fundamentals of the in situ PL spectroelectrochmical method to determine electrochemical potentials of isolated SWNTs and microenviromental effects on the electronic states of the SWNTs, electronic states of SWNTs with a single chirality, and empirical prediction for the electronic potentials of the SWNTs. Such electronic state determination is important for detailed understanding about fundamental properties of the SWNTs and their applications, especially in electronic device applications of the nanotubes. [DOI: 10.1380/ejssnt.2015.179]

著者

A. Mosca Conte O. Pulci R. Del Sole A. Knapik J. Bagniuk J. Lojewska L. Teodonio M. Missori

出版者

公益社団法人 日本表面科学会

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.10, pp.569-574, 2012-10-13 (Released:2012-10-13)

参考文献数

29

被引用文献数

4 15

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Paper is the most widely used writing support due to the remarkable properties of its principal component - cellulose - one of the most abundant biomaterials present on Earth. However, due to the complexity of the material, an exhaustive picture of its degradation pathways is still missing. In this paper, we will present recent results and progresses obtained in the comprehension of the role of cellulose oxidation in the yellowing of ancient paper. Visible and ultraviolet spectra of cellulose in ancient paper samples and reference modern samples artificially aged have been interpreted with the aid of ab-initio Time-Dependent Density Functional Theory calculations. Through the comparison of measured and calculated absorption spectra, several oxidized forms of cellulose polymers, acting as chromophores, and responsible for ancient paper yellowing were identified. The relative concentration of ketones and aldehydic groups depends on the environmental conditions in which samples were stored along their life. [DOI: 10.1380/ejssnt.2012.569]

著者

Ryo Tsuchitani Hiroshi Nakanishi Hideaki Kasai

出版者

公益社団法人 日本表面科学会

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.11, pp.138-141, 2013-12-28 (Released:2013-12-28)

参考文献数

31

被引用文献数

2 6

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Based on density functional theory, we report an initial degradation reaction before a ring-opening reaction which is a traditional degradation reaction in imidazolium-based anion exchange membranes (AEMs) and has been reported by several experimental groups. In the present work, a 1-ethyl-3-(4-vinylbenzyl) imidazolium (EVIm) monomer is focused as a part of imidazolium-based AEMs. Firstly, a hydroxide anion is put to the EVIm monomer and the geometry is optimized. Secondly, the minimum reaction path along the ring-opening reaction is calculated and it is concluded that the EVIm monomer is resistant to the ring-opening reaction because of the high energy barrier. Further, when the hydroxide anion is put near the EVIm monomer, the C-H bond at the C2 position of imidazole ring is elongated. As the result, the feasibility of a dehydrogenation reaction where the hydrogen bonding to the C2 position desorbs is suggested. Finally, in order to compare the energy barrier to that of the ring-opening reaction, the minimum reaction path along the dehydrogenation reaction is calculated. From these analyses, we propose that the dehydrogenation reaction precedes the ring-opening reaction and it is also much more dominant rather than the ring-opening reaction in the EVIm monomer. [DOI: 10.1380/ejssnt.2013.138]

著者

Takao Sakurai Yoshihiro Momose Keiji Nakayama

出版者

公益社団法人 日本表面科学会

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.3, pp.179-183, 2005 (Released:2005-06-02)

参考文献数

14

被引用文献数

5 7

---

The influence of surface states on photoelectron emission phenomena was investigated to determine the work function precisely. A new method for analyzing the yield spectra of photoelectron emission as a function of temperature has been developed. This method was used to decide the work function and surface state of aluminum metal sheets mechanically scratched and ultrasonically cleaned in organic solvent. The yield spectrum as a function of photon energy exhibited a greatly changed shape with an increase and subsequent decrease in temperature in flowing Q gas under the irradiation of 220 nm wavelength light. The ionization energy of a surface state generated at the surface by the influence of temperature and light was estimated. [DOI: 10.1380/ejssnt.2005.179]

著者

Yuki Nagao

出版者

The Japan Society of Vacuum and Surface Science

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.10, pp.114-116, 2012-04-21 (Released:2012-04-21)

参考文献数

17

被引用文献数

11 11

---

To investigate the proton transport properties of the Nafion thin films on MgO(100) substrates, impedance measurements of the 60 and 400 nm thick thin films were carried out. The proton conductivity of two thin films were quite lower values compared to that of the commercial Nafion membrane, and the thickness dependence of the proton conductivity was also observed. To investigate in-plane and out-of-plane molecular vibrations in an identical 400 nm thick film of Nafion on the MgO(100) substrate, an infrared p-polarized multiple-angle incidence resolution spectrometry (p-MAIRS) technique was carried out. The in-plane spectrum showed well-known spectrum, however, the out-of-plane spectrum was quite different compared to the in-plane spectrum. The largely different shapes of the spectra clearly indicate that the 400 nm thick film of Nafion has an anisotropic molecular structure. [DOI: 10.1380/ejssnt.2012.114]

著者

Rei Hobara Shinya Yoshimoto Shuji Hasegawa Katsuyoshi Sakamoto

出版者

The Japan Society of Vacuum and Surface Science

雑誌

e-Journal of Surface Science and Nanotechnology (ISSN:13480391)

巻号頁・発行日

vol.5, pp.94-98, 2007-04-30 (Released:2007-04-30)

参考文献数

106

被引用文献数

30 38

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We present a method to prepare tungsten tips for use in multi-tip scanning tunneling microscopes. The motivation behind the development comes from a requirement to make very long and conical-shape tips with controlling the cone angle. The method is based on a combination of a “drop-off” method and dynamic electrochemical etching, in which the tip is continuously and slowly drawn up from the electrolyte during etching. Its reproducibility was confirmed by scanning electron microscopy. Comparison in tip shape between the dynamic and static methods was shown. [DOI: 10.1380/ejssnt.2007.94]