本文对国际科学计量学杂志《Ｓｃｉｅｎｔｏｍｅｔｒｉｃｓ》１９７９－１９９１年的研究论文内容、栏目、作者及国别和编委及国别作了计量分析，揭示出科学计量学研究的重点、活动的中心及发展趋势，说明了学科带头人在发展科学计量学这门新兴学科中的作用。

国际刊物《Scientometrics》文献计量研究

Graphene edges are of particular interest since their orientation determines the electronic properties. Here we present a detailed Raman investigation of graphene flakes with edges oriented at different crystallographic directions. We also develop a real space theory for Raman scattering to analyze the general case of disordered edges. The position, width, and intensity of G and D peaks are studied as a function of the incident light polarization. The D-band is strongest for polarization parallel to the edge and minimum for perpendicular. Raman mapping shows that the D peak is localized in proximity of the edge. For ideal edges, the D peak is zero for zigzag orientation and large for armchair, allowing in principle the use of Raman spectroscopy as a sensitive tool for edge orientation. However, for real samples, the D to G ratio does not always show a significant dependence on edge orientation. Thus, even though edges can appear macroscopically smooth and oriented at well-defined angles, they are not necessarily microscopically ordered.

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Raman Spectroscopy of Graphene Edges

The electronic properties of graphene, a two-dimensional crystal of carbon atoms, are exceptionally novel. For instance, the low-energy quasiparticles in graphene behave as massless chiral Dirac fermions which has led to the experimental observation of many interesting effects similar to those predicted in the relativistic regime. Graphene also has immense potential to be a key ingredient of new devices, such as single molecule gas sensors, ballistic transistors and spintronic devices. Bilayer graphene, which consists of two stacked monolayers and where the quasiparticles are massive chiral fermions, has a quadratic low-energy band structure which generates very different scattering properties from those of the monolayer. It also presents the unique property that a tunable band gap can be opened and controlled easily by a top gate. These properties have made bilayer graphene a subject of intense interest. In this review, we provide an in-depth description of the physics of monolayer and bilayer graphene f...

Properties of graphene: a theoretical perspective

A brief review is given of electronic and transport properties of carbon nanotubes obtained mainly in a k · p scheme. The topics include a giant Aharonov–Bohm effect on the band gap and a Landau-level formation in magnetic fields, magnetic properties, interaction effects on the band structure, optical absorption spectra, and exciton effects. Transport properties are also discussed including absence of backward scattering except for scatterers with a potential range smaller than the lattice constant, its extension to multi-channel cases, a conductance quantization in the presence of short-range and strong scatterers such as lattice vacancies, and transport across junctions between nanotubes with different diameters. A continuum model for phonons in the long-wavelength limit and the resistivity determined by phonon scattering are reviewed as well.

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Theory of Electronic States and Transport in Carbon Nanotubes

This paper addresses the scope for more integrated general analysis of diversity in science, technology and society. It proposes a framework recognizing three necessary but individually insufficient properties of diversity. Based on 10 quality criteria, it suggests a general quantitative non-parametric diversity heuristic. This allows the systematic exploration of diversity under different perspectives, including divergent conceptions of relevant attributes and contrasting weightings on different diversity properties. It is shown how this heuristic may be used to explore different possible trade-offs between diversity and other aspects of interest, including portfolio interactions. The resulting approach offers a way to be more systematic and transparent in the treatment of scientific and technological diversity in a range of fields, including conservation management, research governance, energy policy and sustainable innovation.

A General Framework for Analysing Diversity in Science, Technology and Society

We study the lattice distortion in graphite ribbons of a nanometer width by taking account of the electron-phonon interaction in the tight binding model In the ribbons with armchair edges, the typical Kekule structure appears near the edges depending on the distribution of the bond orders On the other hand, the zigzag ribbons do not undergo bond alternations along the ribbon axis, implying less Peierls instability Special emphasis is put on the survival of the edge state which forms almost flat bands and a sharp peak in the density of states in consideration of the electron-phonon interaction

Lattice Distortion in Nanographite Ribbons

The conductance of carbon nanotubes with a vacancy is studied in a tight-binding model. We examine the Fermi energy e dependence of the conductance and show it is quantized into zero, one, and two times the conductance quantum $e^{2}/\pi\hbar$ depending on the type of vacancy in the half-filled case, i.e., e= 0. In the presence of a magnetic field, the conductance is scaled by the component of the magnetic field in the direction of the vacancy.

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Conductance of Carbon Nanotubes with a Vacancy

We report first-principles electronic-structure calculations using local density approximation in density functional theory for hexagonally bonded hetero-sheets ${\mathrm{BNC}}_{x}$ consisting of graphite and boron-nitride strips. We find a class of electron states that are localized at borders of the heterosheet. Calculations for other heterosheets and homosheets, C, BN, and ${\mathrm{BC}}_{3},$ clarify universal features of the border states, edge states, and nearly-free-electron states. Electronic properties related to the border states in planer or tubular ${\mathrm{BNC}}_{x}$ are discussed.

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Border states in heterosheets with hexagonal symmetry

Effects of impurities with a strong and short-range potential are studied in carbon nanotubes within a k · p scheme. The calculated conductance approaches those obtained for nanotubes with a lattice vacancy when the strength of the potential is sufficiently large. The conductance at e=0 is analytically shown to be quantized into zero, one, and two times of the conductance quantum $e^2/\pi\hbar$ depending on the difference in the number of vacancies at A and B sublattices in nanotubes with a sufficiently large diameter.

Effective-mass theory of carbon nanotubes with vacancy

This analysis aims at capturing current inventive activities in nanotechnologies based on the analysis
of patent applications to the European Patent Office (EPO).

/pdf/capturing-nanotechnology-s-current-state-of-development-via-4iqgegjy3j.pdf

Masatsura Igami

Papers

Lattice Distortion in Nanographite Ribbons

Conductance of Carbon Nanotubes with a Vacancy

Border states in heterosheets with hexagonal symmetry

Effective-mass theory of carbon nanotubes with vacancy

Capturing Nanotechnology's Current State of Development via Analysis of Patents