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
参考文献数
68

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
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
尾﨑 紀昭 Fabio Nudelman
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.46, no.3, pp.46-3-04, 2019 (Released:2019-11-13)
参考文献数
51

With some exceptions, most land plants are static. Being static always involves the risk of being preyed. To counter that, plants have evolved various defence mechanisms against herbivores. These defence mechanisms can be divided into two main strategies. The first is called chemical defence, which involves synthesizing and storing organic compounds such as alkaloids, terpenes, polyphenols, and proteolytic enzymes. These organic compounds act as chemical weapons that are toxic to herbivores, or causes digestion and nutrient blockages. The second mechanism is physical defence, where the cellulose in the cell walls is often reinforced with deposits of inorganic minerals, forming an organic-inorganic hybrid armour. In this paper, we review several reports on plant biomineralization, which is an example of physical defence in plants, and discuss the molecular mechanism and significance of the mineral formation process from a biological point of view.
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
水野 元博 宮東 達也 新屋 隆士
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.4, pp.268-273, 2016 (Released:2017-05-31)

For hydrated proteins, hydration waters largely contribute to the structure and properties of proteins. Therefore, the information of the dynamics of hydration waters in proteins is very important for understanding unique structure, function and crystal growth of protein. In the present study, the change in the rotational motion of water molecules around dynamical transition point (T_D〜220 K) was investigated for hydrated lysozyme using solid-state ^2H NMR. An Arrhenius-type temperature dependence of correlation time for the rotational motion of water molecules was observed above and below T_D. Although the water molecules at the surface of proteins undergo fast isotropic rotation above T_D, 180° flip becomes main motion of water molecules below T_D. Thus, the dynamics of hydrated water is found to be suppressed below T_D. The large distribution of the electric field gradient at ^2H observed below T_D indicates the glassy state of hydration water in protein.
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
黒田 登志雄 Lacmann Rolf
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.6, no.3, pp.51-64, 1979-12-25

The new interpretation on habits ofice growing from vapour is proposed. The primary habits of ice alternate three times (plates→ - 4℃→ columns → -10℃ → plates→from -20℃ to -35℃ → columns) with decreasing temperature. The theory is based on a viewpoint that the surface of ice just below 0℃ is covered with a quasi liquid layer, whose depth or coverage 〓 decreases with falling temperature, and therefore the growth mechanism of a surface changes also as followings : i) Vapour-Quasi Liquid-Solid-Mechanism (〓>1) , ii) Adhesive Growth on a surface strongly adsorbed by water molecules (0.01<〓<1) and iii) Two Dimensional Nucleation Growth on a singular surface (〓<0.01) . As the change in surface structure as well as growth mechanism depend on surface orientation, the complicated habits change is caused mainly by the combination of growth mechanism of each surface, i.e. {0001} and {101^^-0 }. The first and second transition temperature are expected to be independent on absolute supersaturation Δp as same as experiments. On the other hand the third one is the temperature where the two dimensional nucleation growth of {0001} surface reaches the one of { 101^^-0}, so that it falls with decreasing Δp. The observed marked columnar crystals can be explained only by {0001} account of spherical volume diffusion field near taking surfaces and cylindrical one near {1010} surfaces. For plate like crystals between - 10℃ and -20℃ to -35℃ the surface diffusion from {0001} to {101^^-0} and volume diffusion with cylindrical symmetry near {101^^-0} surfaces are very important.