著者
堂寺 知成
出版者
日本結晶成長学会
雑誌
日本結晶成長学会誌 (ISSN:03856275)
巻号頁・発行日
vol.36, no.1, pp.16-23, 2009-04

ソフト準結晶が近年話題になっている.この小論では,まずソフト準結晶創成には多元系,複雑分子を用いるなど5回対称クラスターや新たな長さスケールの導入が必要であることを計算機実験の立場から論じた.また,高次元結晶学を解説し,準結晶探索には近似結晶探索が鍵となっていることを記した.準結晶の起源論には2つあり,エネルギーとエントロピーの2つの立場があるが,エントロピー説に関連して準結晶特有のフェイゾン乱れを解説した.さらに,ABC星型高分子系のタイリング構造を説明し,格子高分子の計算機実験の予測を経た高分子準結晶発見への道筋を解説した.最後に,フェイゾン動力学の考慮も準結晶探索には重要な要素になっていることも論じた.
著者
若濱 五郎
出版者
日本結晶成長学会
雑誌
日本結晶成長学会誌 (ISSN:03856275)
巻号頁・発行日
vol.18, no.2, pp.252-253, 1991-12-15
著者
マリオ ランゲン 日比谷 孟俊 江口 実 イワン エグリ
出版者
日本結晶成長学会
雑誌
日本結晶成長学会誌 (ISSN:03856275)
巻号頁・発行日
vol.24, no.2, 1997-07-01

Density of molten silicon was measured by electromagnetic levitation in the wide temperature range including underccoled condition of about 300K. Density was 2.52 g/cm^3 at m.p. and volumetric expansion coefficient was.〜1.6 x 10^<-4>/K near the m.p. Density anomaly was not observed.
著者
佐藤 清隆
出版者
日本結晶成長学会
雑誌
日本結晶成長学会誌 (ISSN:03856275)
巻号頁・発行日
vol.18, no.2, pp.255-256, 1991-12-15
著者
西永 頌
出版者
日本結晶成長学会
雑誌
日本結晶成長学会誌 (ISSN:03856275)
巻号頁・発行日
vol.16, no.3, pp.234-235, 1990-03-25
著者
広瀬 洋一 細野 浩平
出版者
日本結晶成長学会
雑誌
日本結晶成長学会誌 (ISSN:03856275)
巻号頁・発行日
vol.31, no.4, pp.330-334, 2004-11-30

気相からのダイヤモンドを合成する方法であるCVD法(化学気相堆積法)についての解説である.従来は炭化水素のガス(例えばメタン,CH_4)と水素(H_2)を混合し,加熱やプラズマを使い,励起・分解してダイヤモンドを基板上に成長させている.しかし,ここでは原料にメタノールを用いると,キャリアガスとして水素を使用せずに,ダイヤモンド結晶を合成する基本的な考え方,合成装置について述べている.本方法は常圧で,ダイヤモンド合成が出来ること,装置もガラス瓶3本で構成されており,広く普及を図れば,高校生への理科教育の啓蒙活動の一助になるものと思われる.この簡易ダイヤモンド合成装置は簡単,安価(数百円),安全の特徴をもっている.また,ダイヤモンド合成の基本を見直し,そこから示唆されたアイディア(燃焼炎はプラズマである)を活かし,大気中でダイヤモンド結晶を合成する新たな燃焼炎法についても紹介している.ここでは,3000℃のアセチレン-酸素炎を用い,ガス流量比(O_2/C_2H_2)が0.8〜1.0,基板温度が500〜850℃の範囲で,基板(Si,Moなど)上にダイヤモンドが高速成長(数10μm/h〜100μm/h)する事を見出した.得られたダイヤモンドはSEM観察,ラマン分光により評価した.この燃焼炎法は,高速成長,大面積化,装置の構成が簡単,安価などの特徴を有していることから,多くの研究者が関心を持つことを願う.
著者
大谷 茂樹
出版者
日本結晶成長学会
雑誌
日本結晶成長学会誌 (ISSN:03856275)
巻号頁・発行日
vol.25, no.3, 1998-07-01

Single crystals of the Va group transition metal diborides, VB_2, NbB_2 and TaB_2, were prepared by the RF-heated floating zone method. Influence of the growth conditions on the crystal quality was examined. The growth directions and the micro-hardness were measured, and compared with the other diboride crystals, ZrB_2 and WB_2.
著者
野口 祐二 井上 亮太郎 宮山 勝
出版者
日本結晶成長学会
雑誌
日本結晶成長学会誌 (ISSN:03856275)
巻号頁・発行日
vol.43, no.3, pp.161-168, 2016 (Released:2017-08-23)
参考文献数
40

The photovoltaic (PV) effect in polar materials offers great potential for light-energy conversion that generates a voltage beyond the bandgap limit of present semiconductor-based solar cells. Ferroelectrics have received renewed attention because of the ability to deliver a high voltage in the presence of ferroelastic domain walls (DWs). We report an unusually large PV response induced by ferroelastic DWs — termed ‘DW’-PV effect. The precise estimation of the bulk PV tensor in single crystals of barium titanate enables us to quantify the giant PV effect driven by 90°DWs. We show that the DW-PV effect arises from an effective electric field consisting of a potential step and a local PV component in the 90° DW region. This work offers a starting point for further investigation into the DW-PV effect of alternative systems and opens a reliable route for enhancing the PV properties in ferroelectrics based on the engineering of domain structures in either bulk or thin-film form.
著者
金田 泰佳 八田 珠郎
出版者
日本結晶成長学会
雑誌
日本結晶成長学会誌 (ISSN:03856275)
巻号頁・発行日
vol.41, no.4, pp.194-204, 2015 (Released:2017-05-31)

Chocolate is a suspension in which solid particles of sugar and cocoa powder are dispersed at high concentrations in a continuous phase of cocoa butter. Many of chocolate's physical properties are thus determined by the behavior of cocoa butter crystal, which plays numerous essential roles in providing chocolate with a pleasing appearance, snap at room temperature, and smooth melting in the mouth. On the other hand, a fat bloom appears on chocolate when the unfavorable properties of cocoa butter crystal are manifested. Fat bloom is a condition in which the fine texture of fat crystal is lost for some reason and the chocolate becomes non-uniform. Chocolate fat bloom is classified into various types by the form of chocolate it is found on and the storage conditions that cause it. However, the relationships between the causes and results of bloom are diverse, and the classification of chocolate fat bloom is complicated. In this article, we classify chocolate fat bloom according to bloom morphology. Organizing the morphological states can help us to understand the developing mechanism, which gives a complicated flow chart showing the dependence on the type of chocolate item and its storage conditions.
著者
佐々木 拓生 高橋 正光
出版者
日本結晶成長学会
雑誌
日本結晶成長学会誌 (ISSN:03856275)
巻号頁・発行日
vol.42, no.3, pp.210-217, 2015 (Released:2017-05-31)

Dislocation-mediated strain relaxation during lattice-mismatched InGaAs/GaAs(001) heteroepitaxy was studied through in situ x-ray reciprocal space mapping (in situ RSM). At the synchrotron facility SPring-8, a hybrid system of molecular beam epitaxy and x-ray diffractometry with a two-dimensional detector enabled us to perform in situ RSM at highspeed and high-resolution. Using this experimental setup, the strain relaxation processes were classified into four thickness ranges with different dislocation behavior. In order to discuss this observation quantitatively, a strain relaxation model was proposed based on the Dodson-Tsao's kinetic model, and its validity was demonstrated by good agreement with the experimental residual strain. In addition to the single InGaAs layer, strain relaxation processes in multi-layer structures are discussed.
著者
川井 清司
出版者
日本結晶成長学会
雑誌
日本結晶成長学会誌 (ISSN:03856275)
巻号頁・発行日
vol.41, no.4, pp.185-193, 2015 (Released:2017-05-31)

Crystallization and glass transition behaviors of carbohydrate materials were reviewed. Firstly, effects of water content, molecular weight, and types of monomer and chemical bond on the glass transition temperature, effect of aging treatment on the glassy properties, and crystallization behavior of low molecular carbohydrate materials such as sucrose and trehalose were explained. Secondary, gelatinization and/or melting, recrystallization (retrogradation), and glass transition properties of starch were explained. Finally, cookie was employed as a typical carbohydrate enriched food, and practical significance of the physical control was exhibited.
著者
三浦 巌 高橋 正典 青木 聡之 安芸 晋冶
出版者
日本結晶成長学会
雑誌
日本結晶成長学会誌 (ISSN:03856275)
巻号頁・発行日
vol.31, no.3, 2004
参考文献数
1

The usefulness of low-power P MR in the study of polymorphous and molecular dynamics was examined. The milling, high temperature and humidification effect on amino acids crystal were studied by PMR. The results of these experiments were demonstrated that the normal liquid PMR system can be used as a powerful analytical tool of the solid materials.