Highly-ordered FePd Nanostructure and Magnetic Properties in Ultrahigh Density Magnetic Recording

Jun-Goo Kang,K. Takanashi,S. Mitani,Y. Sakuraba,Jae-Geun Ha 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Continuous deformation of flat-foldable crease patterns via interpretation as set of twist-patterns

Yamamoto Yohei,Mitani Jun 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.3

In the study of origami, various parametric methods have been proposed to design crease patterns under geometric conditions for flat-folding. Each design method contributes to finding a desirable crease pattern, e.g., one with superior engineering properties, by manipulating parameters. On the other hand, to continuously deform other crease patterns, it is necessary to recreate it once with such a parametric method; however, this inverse problem is less studied. This paper is basic research to solve this problem and to allow parametric deformation of flat-foldable crease patterns. Given crease patterns are interpreted as networks consisting of twist-folding patterns that can be generated by an existing parametric method named twist-based design method. Then, by manipulating the parameters, the crease pattern is deformed. Importantly, any flat-foldable crease pattern having no crease line connecting two points on the boundary can be targeted, and it is locally guaranteed that deformed crease patterns have non-intersecting crease lines and are flat-foldable. The proposed method contributes to increased origami variations by deformations of existing crease patterns.

Method for solving origami tessellation hole problem using triangle twist folding

Yamamoto Yohei,Nakazato Riku,Mitani Jun 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.1

Origami tessellations are geometric pieces folded from a single sheet of paper with flatly overlapped facets. Most existing origami tessellations are constructed by first marking a grid of crease lines on the paper and then arranging repeating patterns along the grid. However, this design method is limited because it cannot design origami tessellations with patterns that cannot be represented on a grid, such as a regular pentagon. This paper proposes a new construction method for origami tessellations that solves this problem and enriches these varieties. In the proposed method, a boundary of an origami tessellation is determined first, and then patterns called triangle twist fold patterns are placed inside the boundary. A similar approach is known as a hole problem, although in this paper, the problem is redefined and discussed in a form suitable for origami tessellations. As a result, a grid-independent construction method was proposed, and new origami tessellations were obtained by using software that implements the method.

교정치료에서 있어서 외과용 mini-plate를 이용한 Skeletal anchorage system(SAS)의 사용법(I)

Choe, Yong-Hyeon,Jo, Hyeong-Jun,Kim, Su-Hwan,Kim, Jin-Yeong,Kim, Ga-Yeong,Umemori, M.,Sugawara, J.,Mitani, H.,Kawamura, H. 대한치과의사협회 1999 대한치과의사협회지 Vol.37 No.3

간단한 Nance holding arch를 이용한 상악구치부의 Distalization (I)

Choe, Yong-Hyeon,Jo, Hyeong-Jun,Kim, Su-Hwan,Kim, Ga-Yeon,Go, Byeong-Guk,Kim, Jin-Yeong,Igarashi, K.,Mitani, H. 대한치과의사협회 1998 대한치과의사협회지 Vol.36 No.7

Approximating 3D surfaces using generalized waterbomb tessellations

Yan Zhao,Yuki Endo,Yoshihiro Kanamori,Jun Mitani 한국CDE학회 2018 Journal of computational design and engineering Vol.5 No.4

Origami has received much attention in geometry, mathematics, and engineering due to its potential to construct 3D developable shapes from designed crease patterns on a flat sheet. Waterbomb tessellation, which is one type of traditional origami consisting of a set of waterbomb bases, has been used to create geometrically appealing 3D shapes and been widely studied. In this paper, we propose a method for approximating target surfaces, which are parametric surfaces of varying or constant curvatures, using generalized waterbomb tessellations. First, we generate a base mesh by tiling the target surface using waterbomb bases. Then, by applying a simple numerical optimization algorithm to the base mesh, we achieve a developable waterbomb tessellation, which can be developed onto a plane without stretching. We provide a prototype system using which the user can adjust the resolution of the tessellation and modify waterbomb bases. Our work could expand the exploration of building developable 3D structures using origami.

Temperature dependence of reliability characteristics for magnetic tunnel junctions with a thin MgO dielectric film

Choi, Chul-Min,Oh, Young-Taek,Kim, Kyung-Jun,Park, Jin-Suk,Sukegawa, Hiroaki,Mitani, Seiji,Kim, Sung-Kyu,Lee, Jeong-Yong,Song, Yun-Heub Institute of Physics 2016 Semiconductor science and technology Vol.31 No.7

<P>Temperature dependence of the reliability characteristics of magnetic tunnel junctions (MTJs) with a thin (∼1 nm thick) MgO dielectric film were investigated by numerical analyses based on the E-model, 1/E-model, and power-law voltage V-model, as well as by measuring time-dependent dielectric breakdown (TDDB) degradation. Although the tunneling process giving rise to TDDB is still under debate, the temperature dependence of TDDB was much weaker using the 1/E model than the E-model or power-law model. The TDDB data measured experimentally in CoFeB/MgO/CoFeB MTJ devices also showed rather weak temperature dependence, in good agreement with the numerical results obtained from the 1/E-model considering the self-heating effect in MTJ devices. Moreover, we confirmed by interval voltage stress tests that some degradation in the MgO dielectric layer occurred. Based on our findings, we suggest that to characterize the reliability of MTJs, combined temperature measurements of TDDB and 1/E-model analyses taking the self-heating effect into account should be performed.</P>

Constructing foldable cylindrical surfaces via unfolded waterbomb origami units

Zhao Yan,Wei Yinglei,Jia Yiyang,Li Shiling,Zhang Mingyue,Zeng Lanling,Yang Yang,Mitani Jun 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.4

Origami tessellations have shown the potential to be utilized for approximating curved target surfaces by folding a set of elemental units. As those units are in partially folded states, the origami approximation captures the outline of the target while demonstrating a corrugated surface. In this paper, we focus on the cylindrical surface and propose a method for constructing its discrete version via square or rectangular units with crease patterns inspired by the waterbomb tessellation. We unify the unit size through optimization to realize cost-efficient constructions. Three-dimensional curved structures are deployed by folding collinear creases between adjacent rows of units and the other creases in each row are remained unfolded. The deployed structure can still be folded to a compact state by folding all creases. To flexibly approximate the outline of the target surface, we analyse relationships between the width and height of the rectangular unit and utilize variations of the waterbomb tessellation to control the region of the origami structure when fully folded. The proposed method provides a novel solution to the so-called inverse-origami-design problem for generating foldable cylindrical surfaces using unfolded waterbomb origami units.

편액에 함의된 경관 및 상징요소의 출현특성 - 한국의 담양원림과 중국의 소주원림을 중심으로 -

함광민 ( Ham Kwang-min ),이수화 ( Li Shu-hua ),장아평 ( Zhang Ya-ping ),미타니토루 ( Mitani Toru ),장준화 ( Zhang Jun-hua ) 한국전통조경학회(구 한국정원학회) 2016 한국전통조경학회지 Vol.34 No.4

16세기 한국의 담양원림과 중국 소주원림의 편액에 함의된 경관 및 상징요소의 출현특성을 비교분석한 본 연구의 결과는 다음과 같다. 첫째, 편액에 함의된 경관요소 중, 식물요소의 출현율이 양국 원림에서 높게 나타났다. 담양원림의 경우 원림 주변에 조성된 죽림과 자연림이, 소주 원림의 경우 인공적으로 조성한 가산(假山)과 수변 주변의 연, 대나무, 소나무를 포함한 다양한 식물이 편액의 의미에 반영 된 것이 특징이다. 반면, 풍경의 정취를 고조시키는 비, 바람, 달 등을 포함한 기후 및 천체요소는 담양원림의 편액과, 건물과 다리, 책 등을 포함한 인공요소는 소주원림의 편액과 관련되는 것이 특징이다. 이는 산수가 수려한 곳에 찾아 들어가 인공을 최소화하고 자연과의 합일을 미적 이상으로 삼는 한국원림의 특징과, 평탄한 곳에 원림의 경계와 경물을 인공적으로 조성하고 자연과의 동화를 미적 이상으로 삼는 중국원림의 특징을 명확히 하는 근거로 수렴될 수 있겠다. 둘째, 편액에 함의된 상징요소 중, 성인(聖人)의 기본덕목인 도덕적 인품이 두 지방 원림의 사유세계에 있어 보편적 특징으로 나타난다. 반면, 정치안정에 대한 의지는 담양원림의 편액과, 선조를 회고하고 기리는 마음은 소주원림의 편액과 관련되는 것이 특징이다. 이는 사회ㆍ정치적 양상과 연관된 것으로, 당시 호남세력들의 정치적 이상이, 강남 봉건세력들의 유교적 이념이 원림 향유 속에 드러난 것으로 이해된다. 셋째, 담양원림의 편액에 함의된 상징요소 「도덕」과 「정치안정」은 기후와 천체요소가 만들어내는 정경(情景)적 분위기와, 소주원림의 편액에 함의된 상징요소 「도덕」은 식물이 갖는 상징적인 의미와 깊게 관련되어 있고, 이는 한중 원림의 영역을 눈에 보이지 않는 비가시(非可視)영역으로 확장하는 특징과 연결된다. The comparative analysis result of appearance characteristic of landscape elements and symbolic elements implied by the tablets on the 16th century`s Korean Damyang garden and Chinese Suzhou garden is as follows. First, among the landscape elements implied in the tablets, appearance rate of botanical factors appeared high in the gardens of both areas. Damyang garden displayed bamboo grove and natural forest around the garden, while Suzhou garden displayed artificial mountain(假山) created artificially and a variety of plants including lotus, bamboo, and pine surrounding it were associated with the significance of the tablets. On the other hand, climatic/celestial elements including the rain, wind, and the moon were associated with the tablets of Damyang garden, while the artificial factors such as the building, bridge, and book, etc. were mostly were associated with the tablets of Suzhou garden. Second, among the symbolic elements included in the tablets, ethical personality which is the basic virtue of a noble man(聖人), was the universal characteristic of the meditation world of the garden in both areas. However, a will for political stability was mostly associated with the tablets of Damyang garden, while the retrospect heart for the immortal was mostly associated with the signboard in Suzhou garden. It was concerned with political ideal and the thought of Confucianism respectively. Third, the symbolic elements that appeared frequently in the tablets of Damyang garden, 「Ethics」 and 「Political stability」, were associated with the scene atmosphere created by the climatic elements and celestial elements. On the contrary, the symbolic elements which most frequently appeared in the tablets of Suzhou garden, 「Ethics」, was associated with the symbolic significance of the plant. The invisible space of gardens was expanded by tablets in both areas.