著者
中道 正之
出版者
心理学評論刊行会
雑誌
心理学評論 (ISSN:03861058)
巻号頁・発行日
vol.45, no.3, pp.334-348, 2002 (Released:2019-04-12)
著者
早川 竜馬 Tuhin Shuvra Basu 若山 裕
出版者
一般社団法人 日本物理学会
雑誌
日本物理学会誌 (ISSN:00290181)
巻号頁・発行日
vol.77, no.5, pp.298-303, 2022-05-05 (Released:2022-05-07)
参考文献数
29

単分子を集積回路の構成要素とする分子デバイスのアイディアは,1974年にAviramとRatnerによる分子ダイオードの提案に始まる.その後,単分子接合を効率的かつ再現性よく形成する技術が確立され,単分子トランジスタや単分子メモリなど興味深いデバイス提案がなされてきた.しかしながら,50年近く経った現在でも,未だ実用化には程遠いのが現状である.分子の持つ“優れた量子機能”を如何に実用デバイスの中で発現するかが重要な鍵となる.一方で現在のエレクトロニクスを支えるシリコンデバイスも大きな転換点を迎えている.素子の微細化によるトランジスタの高性能化は限界を迎え,従来とは異なる新しい動作原理で駆動するトランジスタの開発が求められている.そのため,ソース電極からドレイン電極へ流れる電荷の流れをトンネル効果により制御するトンネルトランジスタは,高速動作,低消費電力を兼ね備えた次世代トランジスタとして期待されている.しかしながら,“0”と“1”の2値動作という点では従来のトランジスタと変わらない.上記背景から,筆者らは現在のシリコンプロセスに適合した分子トランジスタを開発するため,分子を量子ドットに用いた縦型トランジスタを提案している.分子は,原子レベルで厳密に規定された均一な粒子であり,サイズ分布の無い理想的な量子ドットとして機能する.分子の持つ離散準位(分子軌道)を利用した単電子トンネル伝導を誘起できれば,低消費電力化に加え,多値化が実現でき,トランジスタのさらなる高性能化が期待できる.これまで,トランジスタの基本構造である金属–絶縁体–半導体構造の絶縁膜にC60分子を始め様々な分子を集積し,2重トンネル接合として機能することを示してきた.本研究では,上記トンネル素子をさらに縦型トランジスタのチャネル層に応用し,分子軌道を反映したトンネルトランジスタ動作を実証したので報告する.C60分子は3重縮退した最低空軌道と5重縮退した最高被占軌道を持つ.そのため,単一電荷が縮退した分子軌道へ注入されると帯電エネルギーにより縮退準位がシフトし,異なる準位として観測される.実際,20 Kにおいて測定したドレイン電流–ドレイン電圧特性において,縮退した分子軌道が等間隔に観測され,単電子トンネル伝導を確認した.オーソドックス理論を用いたシミュレーションから導出したトンネル接合容量を用い,量子ドット径を算出したところ1.3~1.9 nmとなった.これは,C60分子1~2個分に相当する.チャネル層には104–105個の分子が存在しているが,各分子が孤立分散しているため,少数分子に起因するトンネル伝導を観測できる.また,300 Kにおいても上記伝導機構が維持されており,室温動作も視野に入る.さらに僅か5 nmのチャネル長であるにもかかわらず,4桁にわたるドレイン電流のゲート変調に成功した.これは,分子軌道の変調効果に加え,シリコン基板内に形成される空乏層によりドレイン電流が効果的に制御された結果で,分子をシリコンデバイスに集積する一つの利点と言える.今後,様々な機能性分子を用い,無機材料では実現できない“分子固有の機能”を兼ね備えた次世代トランジスタが実現できると期待される.
著者
吉田 朋広
出版者
東京大学
雑誌
戦略的な研究開発の推進 戦略的創造研究推進事業 CREST
巻号頁・発行日
2014

従属性のあるビッグデータへの統計的モデリングと、確率統計学の原理に則った統計解析の体系化を目指します。とくに、超高頻度金融データ解析を可能とする確率統計的方法を構築し、金融市場のモデリングを通じて、金融技術分野に貢献します。また、時系列データ科学のインフラとなる確率過程に対する統計解析およびシミュレーションのためのソフトウエアを発展させるとともに、SNSのデータ解析による様々な社会的事象の将来予測への応用を行います。

1 0 0 0 自然選書

出版者
中央公論社
巻号頁・発行日
1972
著者
世良 貴史
出版者
岡山大学
雑誌
挑戦的萌芽研究
巻号頁・発行日
2016-04-01

従来の遺伝子治療法の問題点を克服するために、挿入酵素を空間的に標的DNAサイトに近接させることにより位置特異的遺伝子挿入を可能にする新しい技術の開発を目指した。その近接させる手法として、導入遺伝子と標的サイトにそれぞれ特異的に結合する2種類の人工DNA結合タンパク質を柔軟なペプチドリンカーで連結した新しい人工DNA結合タンパク質を作製し、これを用いて、まずは試験管内のモデル系で、標的DNAに別のDNAを特異的に挿入させることに成功した。
出版者
公益社団法人 東京地学協会
雑誌
地学雑誌 (ISSN:0022135X)
巻号頁・発行日
vol.118, no.3, pp.Cover03_1-Cover03_2, 2009-06-25 (Released:2010-03-26)

泥火山噴出物は粘性が高いため約8mの高さをもち,現在でも成長している.噴出口からは間欠的に泥,地下水,メタンを主とするガス,石油が噴出している.噴出箇所は,北東–南西方向の走向をもつ旗山断層に沿っており,地形的には尾根部に位置している.約200m四方の平坦地には数箇所の噴出口があり,それぞれ噴出物の粘性が異なる. (写真・解説:田中和広,宮田雄一郎 2006年6月27日撮影)
著者
浜田 好弘 田中 和広 宮田 雄一郎
出版者
公益社団法人 東京地学協会
雑誌
地学雑誌 (ISSN:0022135X)
巻号頁・発行日
vol.118, no.3, pp.408-423, 2009-06-25 (Released:2010-03-26)
参考文献数
38
被引用文献数
9 8

The geology and geochemistry of mud volcanoes in Taiwan was investigated to elucidate the relationship between their distribution and geological structure and the mechanism of ascending fluid migration from deep underground regions caused by abnormal pore water pressure. A detailed geological survey was carried out to describe the geological structure and the stratigraphy of mud volcanoes in the Pliocene Gutingkeng Formation in the Hsiaokunshui area. Groups of several to tens of mud volcanoes are distributed along the anticline axis within an area of 400 m in diameter. Mud volcanoes are classified into three types on the basis of differences in their morphological features (pudding type, crater type and pool type) corresponding to three types of erupted groundwater having different viscosities. As a result of geochemical studies on groundwater that erupted from mud volcanoes, it is shown that the geochemistry of groundwater that erupted from mud volcanoes distributed along the anticline, such as the Hsiaokunshui mud volcanoes, is characterized by lower δ18O ratios and high concentrations of soluble ions compared to those distributed along the Chishan Fault. Also, it is concluded that pressurized groundwater diluted by water produced during the dehydration of clay minerals ascended through the Chishan Fault and along the Hsiaokunshui anticline. On the other hand, on the basis of high δ18O ratios, it is suggested that the groundwater of mud volcanoes along the Chishan Fault was quickly expelled from underground regions deeper than those along the Hsiaokunshui anticline. Also, the groundwater of mud volcanoes along the Hsiaokunshui anticline ascended through a variety of paths from the mud chamber to the ground surface, and consequently various types of mud volcanoes were formed on the ground surface.
著者
中田 英二 千木良 雅弘
出版者
公益社団法人 東京地学協会
雑誌
地学雑誌 (ISSN:0022135X)
巻号頁・発行日
vol.118, no.3, pp.511-532, 2009-06-25 (Released:2010-03-26)
参考文献数
40
被引用文献数
10 9

Understanding erosion processes is important to prevent natural disasters such as slope failure and bedrock erosion in immature sedimentary rocks. Pliocene–Pleistocene illite-rich, non-smectite mudstone of the Gutingkeng Formation is distributed over 250 km2 in southern Taiwan, forming badlands (locally called moon-world) with mud volcanoes nearby. These volcanoes erupt saline water and natural gas, and producing a Na+, Ca2+, Cl-, and SO42- rich unsaturated Popcorn crust, which covers the mudstone slope surfaces in the moon-world area. In the crust porewater, ion strength reaches about 10 mol/L; zeta potential on particle surfaces shows a highly positive voltage. Repulsion occurs between particles under this high voltage in the crust, which is rapidly slaked to form mud by heavy precipitation. The zone that is rapidly slaked by precipitation reaches 10-20 cm beneath the crust surface. Ion strength of porewater of fresh mudstone is 0.5 mol/L approaches 0 mV (range 0.2-0.5 mol/L, pH 4-6). The surface charge of particles decreases with the infiltration of precipitation into the crust and fresh rock, with a minus surface charge occurring with increased rain infiltration. This leads to many cracks forming on the surface of mudstone, which is different from the mechanism of rapid slaking. Evaporation from the 10-20 cm-thick zone between the crust and the underlying fresh mudstone would stop if water was not supplied from depth, which is supported by in-situ measurements of water evaporation in the field. These mudstones erode readily under high precipitation because of the repulsion caused by the high ion strength of porewater. High-salinity porewater including mudstone is distributed near the active mud volcanoes where saline water rises and there is a rapid uplift rate. Rapid slaking occurred with some elements in the concentrated crust and near the surface drying zone.
著者
Atsushi KOSHIBA Takahiro HIROFUCHI Ryousei TAKANO Mitaro NAMIKI
出版者
The Institute of Electronics, Information and Communication Engineers
雑誌
IEICE Transactions on Information and Systems (ISSN:09168532)
巻号頁・発行日
vol.E102.D, no.12, pp.2377-2388, 2019-12-01 (Released:2019-12-01)
参考文献数
25
被引用文献数
2 4

Non-volatile memory (NVM) is a promising technology for low-energy and high-capacity main memory of computers. The characteristics of NVM devices, however, tend to be fundamentally different from those of DRAM (i.e., the memory device currently used for main memory), because of differences in principles of memory cells. Typically, the write latency of an NVM device such as PCM and ReRAM is much higher than its read latency. The asymmetry in read/write latencies likely affects the performance of applications significantly. For analyzing behavior of applications running on NVM-based main memory, most researchers use software-based emulation tools due to the limited number of commercial NVM products. However, these existing emulation tools are too slow to emulate a large-scale, realistic workload or too simplistic to investigate the details of application behavior on NVM with asymmetric read/write latencies. This paper therefore proposes a new NVM emulation mechanism that is not only light-weight but also aware of a read/write latency gap in NVM-based main memory. We implemented the prototype of the proposed mechanism for the Intel CPU processors of the Haswell architecture. We also evaluated its accuracy and performed case studies for practical benchmarks. The results showed that our prototype accurately emulated write-latencies of NVM-based main memory: it emulated the NVM write latencies in a range from 200 ns to 1000 ns with negligible errors from 0.2% to 1.1%. We confirmed that the use of our emulator enabled us to successfully estimate performance of practical workloads for NVM-based main memory, while an existing light-weight emulation model misestimated.
著者
金森 弘樹 田中 浩 田戸 裕之 藤井 猛 澤田 誠吾 黒崎 敏文 大井 徹
出版者
日本哺乳類学会
雑誌
哺乳類科学 (ISSN:0385437X)
巻号頁・発行日
vol.48, no.1, pp.57-64, 2008 (Released:2008-07-16)
参考文献数
7
被引用文献数
10

西中国地域のツキノワグマUrsus thibetanusの「特定鳥獣保護管理計画」は,第一期(2003~2006年度)と第二期(2007~2011年度)とも,広島県,島根県および山口県の三県で共通の指針の下に策定された.生息頭数調査は,個体の捕獲による標識再捕獲法を用いて2回実施され,1999年当時は約480頭,また2005年当時は約520頭と推定された.有害捕獲は1960年代から始まったが,2000年代に入ると年平均100頭以上へと急増した.とくに,大量出没した2004年には239頭,2006年には205頭にも達した.1996~1999年に比べて2000~2006年は,高齢個体も多数捕獲される傾向にあったが,捕獲個体の性比には変化はなかった.三県の放獣率や除去頭数の差は,地域によって異なったが,これは地域住民や行政の意識の違いに起因すると考えられた.放獣個体の再捕獲率は低かったが,学習放獣による奥地への定着や被害の再発防止効果は十分に検証できなかった.今後は,個体群のモニタリングの継続,錯誤捕獲の減少,地域住民への普及啓発の努力などがいっそう必要である.
著者
平田 利美 前川 麻弥 能美 隆
出版者
一般社団法人 日本質量分析学会
雑誌
Journal of the Mass Spectrometry Society of Japan (ISSN:13408097)
巻号頁・発行日
vol.46, no.4, pp.259-274, 1998 (Released:2007-07-20)
被引用文献数
14 13

Mechanisms of pyrolysis of cellulose which have been presented are reviewed in terms of pathways of the reaction, production of levoglucosan, carbonization and pyrolysis of levoglucosan, and kinetics. In addition measurements with machines are discussed in relation to the pyrolysis. In the section of reaction pathways five models given in diagrams are introduced and indicated lack of clear chemical definition of them, and in the levoglucosan formation six principal models are briefly described, and a proposal of an ion mechanism against a radical mechanism, and different interpretations of effects of fine structures on the reaction and the chain length are pointed out to make important controversial points. In the third section changes in residue structure through carbonization are discussed, and courses of levoglucosan pyrolysis full of variety are shown and significance of researches on the pyrolysis in air is emphasized from viewpoint of fire science. In the fifth section an enormous number of kinetic data presented with different orders of reaction are shown and a kinetics is systematically developed to explain the different reaction orders. In the sixth section, the dependency of data on individual instruments are revealed in the measurement with instruments problems involved in analytical pyrolysis. Understanding of the implication and reasonable choice of the data is shown to be important.
著者
Keizo Hosokawa Kazuya Inagaki
出版者
Japanese Society for Food Science and Technology
雑誌
Food Science and Technology Research (ISSN:13446606)
巻号頁・発行日
pp.FSTR-D-23-00072, (Released:2023-10-18)

Gluten is a component of wheat flour and has a vital function in the manufacturing of processed food via the formation of a three-dimensional network. However, gluten is associated with several diseases, such as wheat allergy and celiac disease, and some humans with gluten hypersensitivity are not able to consume wheat products. To address this problem, not only gluten-free cereal flours but also hydrocolloids and gums as gluten substitutes are used as ingredients for gluten-free products. In this study, gluten-free breadmaking was attempted using only ripe banana flour (RBF) and wheat starch as the materials. To understand the role of RBF for gluten-free breadmaking, unripe banana was ripened and RBF was fractionated into three fractions. It was clarified that the water-soluble low molecular fraction (mainly sugars) in RBF acted as a carbon source for fermentation in the dough and the water-soluble high molecular fraction acted as a gluten substitute. Pectin in the water-soluble high molecular fraction was further analyzed for four fractions separated based on differential solvent solubility. The main pectin was chelate-soluble pectin. The RBF was shown to be a good material for gluten-free breadmaking.
著者
Yuichi ODA Kosaku AMANO Kentaro CHIBA Kenta MASUI Takakazu KAWAMATA
出版者
The Japan Neurosurgical Society
雑誌
NMC Case Report Journal (ISSN:21884226)
巻号頁・発行日
vol.10, pp.285-289, 2023-12-31 (Released:2023-10-14)
参考文献数
19

As per the 2021 World Health Organization (WHO) Classification of Tumors of the Central Nervous System, chordoid glioma (CG) is defined as a slow-growing glial neoplasm categorized as grade II tumor. This tumor is primarily located in the anterior part of the third ventricle, often adheres to important surrounding structures, and is hemorrhagic in nature. Therefore, dissecting this tumor is extremely difficult. In this study, we present the case of a 44-year-old man who initially complained of mild headache and was diagnosed with a homogeneous gadolinium-enhanced lesion in the third ventricle via magnetic resonance imaging. The pathological diagnosis based on his biopsy at the previous hospital was CG. The patient demonstrated no neurological deficit at that time, but the tumor had gradually grown, hydrocephalus appeared 2 years after the tumor was detected, and the patient developed short memory disorder and daytime sleepiness. We resected the tumor via the anterior interhemispheric trans-lamina terminalis approach using a microscope and an endoscope. The residual tumor at the blind spot of the microscopic view was resected under an angled rigid endoscopic view using dedicated tools for transsphenoidal surgery. The tumor was grossly resected, and the histopathological diagnosis was CG. Postoperative neurological findings included slight memory disorder and hypothalamic adrenal dysfunction. No tumor recurrence was reported 3 years post resection. The endoscope-assisted anterior interhemispheric trans-lamina terminalis approach was determined useful for CG resection with minimal surgical complications and without tumor recurrence.