检索结果-南通市图书馆

Pseudogap,Fermi arc,and Peierls-insulating phase induced by 3D-2D crossover in monolayer VSe2

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2019年第1期12卷 165-169页

作者： Yuki Umemoto Katsuaki Sugawara Yuki Nakata Takashi Takahashi takafumi Sato Department of Physics Tohoku UniversitySendai 980-8578Japan WPI-Advanced Institute for Materials Research Tohoku UniversitySendai 980-8577Japan Center for Spintronics Research Network Tohoku UniversitySendai 980-8577Japan

One of important challenges in condensed-matter physics is to realize new quantum states of matter by manipulating the dimensionality of materials,as represented by the discovery of high-temperature superconductivity in atomic-layer pnictides and room-temperature quantum Hall effect in *** sition-metal dichalcogenides(TMDs)provide a fertile platform for exploring novel quantum phenomena accompanied by the dimensionality change,since they exhibit a variety of electronic/magnetic states owing to quantum *** we report an anomalous metal-i nsulator transition in duced by three-dimensional(3D)-two-dimensional(2D)crossover in mono layer 1T-VSe2 grown on bilayer *** observed a complete insulating state with a finite energy gap on the entire Fermi surface in monolayer 1T-VSe2 at low temperatures,in sharp contrast to metallic nature of *** surprisingly,monolayer 1T-VSe2 exhibits a pseudogap with Fermi arc at temperatures above the charge-density-wave temperature,showing a close resemblanee to high-temperature *** similarity suggests a common underlying physics between two apparently different systems,pointing to the importance of charge/spin fluctuations to create the novel electronic states,such as pseudogap and Fermi arc,in these materials.

关键词： transition-metal dichalchogenides 1T-VSe2 charge density wave electronic states pseudogap Fermi arc

Role of Double MgO/ZnO Buffer Layers on Defect Reduction of ZnO Layers Grown on c-Sapphire by P-MBE

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

材料科学与工程（中英文A版） 2011年第3X期1卷 380-389页

作者： Agus Setiawan takafumi Yao Department of Mechanical Engineering Education Indonesia University of Education Bandung 40154 Indonesia Center for Interdisciplinary Research Tohoku University Aramaki Aoba-ku Sendai 980-8578 Japan

Depositional condition of Paleoproterozoic Francevillian carbonate rocks revisited from rare earth element contents

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geoscience Frontiers 2024年第3期15卷 31-49页

作者： Satoshi Yoshida Karen Bakakas Mayika Yuki Ishihara Mathieu Moussavou Hisashi Asanuma Tomohiko Sato takafumi Hirata Cédric Ligna Yusuke Sawaki Amboise Edou-Minko Department of Earth Science and Astronomy The University of Tokyo3-8-1 Komaba Meguro-kuTokyo 153-8902Japan Center for Northeast Asian Studies Tohoku University41 KawauchiAoba-kuSendai 980-8576Japan Department of Geology Universitédes Sciences et Techniques de MasukuBP:90190025 FrancevilleGabon Department of Earth and Planetary Science The University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-0033Japan Geochemical Research Center The University of Tokyo7-3-1HongoBunkyo-kuTokyo 113-0033Japan Graduate School of Human and Environmental Studies Kyoto UniversityYoshida-nihonmatsuSakyo-kuKyoto 606-8501Japan Center for Fundamental Education Okayama University of Science1-1Ridai-choKita-kuOkayama CityOkayama 700-0005Japan

The Paleoproterozoic Francevillian Group in the eastern Gabonese Republic has been recently attracting increasing attention because it includes distinctive macroscopic structures interpreted as eukaryotic ***,its depositional setting and associated redox conditions need to be clearly *** clarify these,petrological studies and rare earth element(REE)abundances of carbonate rocks of the Francevillian Group in the Lastoursville basin were determined with ICP-MS coupled with a laser ablation sampling *** microscopic observations indicate that dolostones in this basin underwent the complicated diagenetic history,including sparitization,decomposition of organic matter,reduction of ferromanganese oxides,silicification,and later *** dolostones of lower Francevillian B(FB)Formation show heterogeneous textures formed by alterations during *** the alterations,changes of REE abundances and degrees of positive Y anomalies appear to have *** indicates that REE signatures in carbonate rocks can vary during *** high Mn contents in the dolostones of upper FB Formation were derived from the reduction of ferromanganese oxides in *** signatures of REE abundance in dolostones can be explained by the mixing of seawater and ferromanganese oxide *** that sense,the dolostones inherited the trace element characteristics of precursor ferromanganese oxides even after the diagenesis.Y/Ho values of the most primary parts of each sample exceed 33,the newly determined threshold value for marine carbonate rocks based on our *** magnitude of the La anomaly values also falls within the range of that of Holocene reefal *** indicate that a precursor of the dolostone of the Francevillian Group was deposited in a marine *** addition,presence of Ce anomalies in the upper FB Formation suggests that the Paleoproterozoic ocean was oxidized to such an ex

关键词： Carbonate diagenesis Francevillian Group LA-ICP-MS Seawater composition Y/Ho fractionation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

蒙药材止泻木子生物碱的分离与纯化

化工学报 2016年第S2期67卷 191-196页

作者：王红英周英男 UCHIDA takafumi MARI Yotsu Yamashita 钱斯日古楞大连工业大学生物工程学院辽宁大连116034 tohoku University Graduate School of Agricultural Science

以夹竹桃科植物止泻木子的干燥种子为原材料,采用乙醇提取法对其生物碱类物质进行粗提取,通过硅胶柱层析和重结晶技术对生物碱粗提物进行分离和纯化。利用核磁共振波谱和质谱法对其一种生物碱单体进行化学结构和分子量鉴定。实验结果表... 详细信息

以夹竹桃科植物止泻木子的干燥种子为原材料,采用乙醇提取法对其生物碱类物质进行粗提取,通过硅胶柱层析和重结晶技术对生物碱粗提物进行分离和纯化。利用核磁共振波谱和质谱法对其一种生物碱单体进行化学结构和分子量鉴定。实验结果表明,用70%乙醇在60℃条件下静止浸取3次,每次提取6h,得到止泻木子总生物碱提取物,其得率达到0.244%。经过硅胶柱分离和重结晶纯化,可获得3种生物碱单体。对HPLC检测纯度达到94.89%的2号生物碱单体进行核磁共振波谱和质谱检测,得知该生物碱单体是一个分子量为356.59的锥丝碱(conessine)。该结果有利于了解以止泻木子为主要成分的蒙药药剂作用机理。

关键词：止泻木子核磁共振硅胶柱分离锥丝碱萃取药物