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Nano Research 2010年第8期3卷 604-611页

作者： Yanfeng Zhang Pengfei Guan Hironari Isshiki Mingwei Chen masahiro yamashita Tadahiro Komeda Institute of Multidisciplinary Research for Advanced Materials Tohoku UniversitySendai 980-0877Japan Center for Nanochemistry Academy for Advanced Interdisciplinary StudiesDepartment of Advanced Materials and NanotechnologyCollege of EngineeringBeijing UniversityBeijing 100871China WPI-Advanced Institute for Materials Research Tohoku UniversitySendai 980-8577Japan Department of Chemistry Graduate School of ScienceTohoku UniversitySendai 980-8578Japan CREST Japan Science and Technology Agency(JST)Saitama 332-0012Japan

Scanning tunneling microscopy/spectroscopy(STM/STS)at 4.8 K has been used to examine the growth of a double-decker bis(phthalocyaninato)yttrium(YP_(c2))molecule on a reconstructed Au(111)*** differential conductance spectra(dI/dV)of a single YPc2 molecule allow the characteristics of the highest occupied molecular orbital(HOMO)and the lowest unoccupied molecular orbital(LUMO)to be ***,lateral distributions of the local density of states(LDOS)have also been obtained by dI/dV mapping and confirmed by first principles *** electronic feature mappings and theoretical calculations provide a basis for understanding the unique STM morphology of YPc2,which is usually imaged as an eight-lobed *** addition,we demonstrate that bias-dependent STM morphologies and simultaneous dI/dV maps can provide a way of understanding the stability of two-dimensional YP_(c2) films.

关键词： Scanning tunneling microscopy/spectroscopy(STM/STS) phthalocyanine electronic structure

Magnetic relaxation behavior of a spatially closed dysprosium(Ⅲ) phthalocyaninato double-decker complex

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Science China Chemistry 2012年第6期55卷 918-925,1178-1184页

作者： KATOH Keiichi UMETSU Kaori BREEDLOVE BRIAN K. yamashita masahiro Department of Chemistry Graduate School of Science Tohoku University 6-3 Aramaki-Aza-Aoba Aoba-ku Sendai Miyagi 980-8578 Japan

The SMM properties of the spatially closed Dy（Ⅲ） double-decker Pc complex Dy（obPc）2 （1）, which is equivalent to a pseudo dinuclear complex, are reported. Complex 1 crystallized with ethanol in the crystal lattice in the monoclinic space group P22/n and was isomorphous with Tb（obPc）2 （3）, which is arranged in a dimer structure along the b axis. The intermetallic Dy-Dy distance was determined to be 0.756 nm. ZMT versus T plots for 1 decreased with a decrease in T, which suggests the existence of an antiferromagnetic （AF） interaction between the Dy3＋ ions. The M-H curve for 1 at 1.8 K showed magnetic hysteresis. In ac susceptibility measurements on a powder sample of 1, which were dependent on the applied ac field, indicating that 1 is an single molecule magnet （SMM）, a maximum appeared at 22 K at an ac frequency 09 of 1488 Hz. The shape of the peaks dras- tically changed, and the peaks did not shift when an Hd~ large enough to suppress the quantum tunneling of the magnetization （QTM） was applied. The energy barrier （A/hc） was estimated to be 44 cm-1 with a pre-exponential factor （r0） of 1.6 × 10-5 s from an Arrhenius plot. Our results suggest that the SMM/magnetic properties of 1 significantly change in a dc magnetic field. These relaxation mechanisms are related to the energy gap of the ground state and to QTM.

关键词： single-molecule magnets dysprosium double-decker complex pseudo dinuclear complex magnetic relaxation process

Controlling Three-Step and Five-Step Spin Transitions by Polymorphism in an Fe^(Ⅲ) Spin Crossover Complex

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Chinese Journal of Chemistry 2024年第8期42卷 879-886页

作者： Yingying Wu Shuang Peng Ziyi Zhang Yue Gao Guangyan Xu Jingwei Dai Zhao-Yang Li masahiro yamashita School of Materials Science and Engineering Nankai University38 Tongyan RoadHaihe Educational ParkTianjin300350 China State Key Laboratory of Medicinal Chemical Biology Nankai UniversityTianjin300071 China Department of Chemistry Graduate School of ScienceTohoku UniversitySendai980-8578 Japan

Comprehensive Summary,Regulating spin crossover(SCO)behavior,especially controlling the spin transition steps,is an important scientific issue,mainly because people aim to control spin bistability and ***,SCO bistability can be regulated by changing the ligand-modifying species,non-coordinated anions,guest molecules,and metal-ion ***,the control of multistability is extremely challenging,especially in Fe(III)SCO ***,we report that[FeIII(H-5-Br-thsa)(5-Br-thsa)]·H2O(5-Br-thsa=(5-bromo-2-hydroxybenzylidene)hydrazinecarbothioamide),a compound we have reported before,exists in two polymorphic forms:polymorph 1 exhibits three-step SCO,and polymorph 2 shows five-step SCO,with multi-step SCO behavior effectively regulated by *** to single-crystal and powder X-ray diffractometry,polymorphs 1 and 2 crystallize in different space groups during their spin transitions,with two-step symmetry breaking observed(Pbcn→Pnc2→Pbcn for polymorph 1;P21/n→Pn→P21/n for polymorph 2).We realized that the behavior of these two polymorphs depends significantly on the structure,including(i)the average Fe—N bond distance,(ii)deformation of octahedral FeIII atoms,and(iii)distinct crystal packing,which account for the large differences observed in magnetic properties.

关键词： Spin crossover Multi-step spin transition Symmetry breaking Polymorphism Magnetic property

Magnetic relaxation behavior of a spatially closed dysprosium（Ⅲ） phthalocyaninato double-decker complex

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中国科学：化学 2012年第6期42卷 889-890页

作者： Keiichi KATOH Kaori UMETSU BRIAN K. BREEDLOVE masahiro yamashita Department of Chemistry Graduate School of Science Tohoku University 6-3 Aramaki-Aza-Aoba Aoba-ku Sendai Miyagi 980-8578 Japan

The SMM properties of the spatially closed Dy(Ⅲ) double-decker Pc complex Dy(obPc)2(1), which is equivalent to a pseudo dinuclear complex, are reported. Complex 1 crystallized with ethanol in the crystal lattice in the monoclinic space group P21/n and was isomorphous with Tb(obPc)2 (3), which is arranged in a dimer structure along the b axis. The intermetallic Dy-Dy distance was determined to be 0.756 nm. χMT versus T plots for 1 decreased with a decrease in T, which suggests the existence of an antiferromagnetic (AF) interaction between the Dy3+ions. The M-H curve for 1 at 1.8 K showed magnetic hysteresis. In ac susceptibility measurements on a powder sample of 1, which were dependent on the applied ac field, indicating that 1 is an single molecule magnet (SMM), a maximum appeared at 22 K at an ac frequency (f) of 1488 Hz. The shape of the peaks drastically changed, and the peaks did not shift when an Hdclarge enough to suppress the quantum tunneling of the magnetization (QTM) was applied. The energy barrier (Δ/ηχ) was estimated to be 44 cm-1with a pre-exponential factor (τt0) of 1.6 × 10-5s from an Arrhenius plot. Our results suggest that the SMM/magnetic properties of 1 significantly change in a dc magnetic field. These relaxation mechanisms are related to the energy gap of the ground state and to QTM.

关键词：镝(Ⅲ) 空间群弛豫行为封闭磁化率测量酞菁交流电场单分子磁体

Dual-radical-based molecular anisotropy and synergy effect of semi-conductivity and valence tautomerization in a photoswitchable coordination polymer

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National Science Review 2023年第6期10卷 200-214页

作者： Jing-Wei Dai Yu-Qin Li Zhao-Yang Li Hai-Tao Zhang Carmen Herrmann Shohei Kumagai Marko Damjanovi? Markus Enders Hiroyuki Nojiri Masakazu Morimoto Norihisa Hoshino Tomoyuki Akutagawa masahiro yamashita State Key Laboratory of Medicinal Chemical Biology Nankai University School of Materials Science and Engineering Nankai University Institute of Inorganic and Applied Chemistry University of Hamburg Department of Chemistry Graduate School of Science Tohoku University Institute of Inorganic Chemistry University of Heidelberg Institute for Materials Research Tohoku University Department of Chemistry Rikkyo University Institute of Multidisciplinary Research for Advanced Materials (IMRAM) Tohoku University

Organic radicals are widely used as linkers or ligands to synthesize molecular magnetic ***,studies regarding the molecular anisotropies of radical-based magnetic materials and their multifunctionalities are ***,a photoisomerizable diarylethene ligand was used to form{[CoⅢ(3,5-DTSQ·-)(3,5-DTCat2-)]2(6F-DAE-py2)}·3CH3CN·H2O(o-1·3CH3CN·H2O,6F-DAE-py2=1,2-bis(2-methyl-5-(4-pyridyl)-3-thienyl)perfluorocyclopentene),a valence-tautomeric(VT) coordination *** directly observed dual radicals for a single crystal using high-field/-frequency(～13.3 T and～360 GHz) electron paramagnetic resonance(EPR) spectroscopy along the c-axis,which was further confirmed by angle-dependent Q-band EPR ***,a conductive anomaly close to the VT transition temperature was observed only when probes were attached at the ab plane of the single crystal,indicative of synergy between valence tautomerism and *** anisotropy studies and density functional theory(DFT) calculations revealed that this synergy is due to electron transfer associated with valence *** study presents the first example of dual-radical-based molecular anisotropy and charge-transfer-induced conductive anisotropy in a photoswitchable coordination polymer.

关键词： valence tautomerization charge transfer photo switching diradical coordination polymer

氰基桥联的[Fe4ⅢNi2Ⅱ]六核单分子磁体

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氰基桥联的[Fe4ⅢNi2Ⅱ]六核单分子磁体

基于元胞自动化模型的三维雪花晶体近似模式的产生(英文)

中国化学会第29届学术年会

作者：李朝阳 Kim R.Dunbar masahiro yamashita Department of Chemistry School of ScienceTohoku University Department of Chemistry Texas A&M UniversityCollege Station

分子磁性材料是一类通过化学方法将自由基或顺磁离子及抗磁配体以自组装的方式组合而形成的分子水平的磁性化合物。在这其中,单分子磁体（Single-Molecule Magnets,SMMs）尤其引人注目1-2,SMMs是指在磁场下能被磁化,而当磁场撤去后仍能... 详细信息

分子磁性材料是一类通过化学方法将自由基或顺磁离子及抗磁配体以自组装的方式组合而形成的分子水平的磁性化合物。在这其中,单分子磁体（Single-Molecule Magnets,SMMs）尤其引人注目1-2,SMMs是指在磁场下能被磁化,而当磁场撤去后仍能保持磁性的单个分子。由于在信息存储方面具有潜在的广泛的应用前景,SMMs日益成为化学、材料物理等学科的研究热点。本文报道了一例氰基桥联的[FeⅢ4NiⅡ2]六核化合物,{[FeⅢ（Tp*）（CN）3]4[NiⅡ（tptz）]2}·MeOH·nH2O（1）,我们通过X射线单晶衍射确定了化合物的结构,如图1a所示,更重要的是我们通过测量化合物的磁性性质（图1b是化合物的直流磁化率对温度的曲线）,成功观测到了缓慢磁驰豫现象,通过对其能垒的计算,可以认定化合物1是一例单分子磁体。

关键词：氰基过渡金属簇合物单分子磁体

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山东大学学报（工学版） 2009年第1期39卷 102-105,117页

作者：李芳佳高尚策唐政石井雅博山下和也富山大学工学部

关于雪花生长过程的计算机模拟已经受到了广泛关注.其中,元胞自动化模型是一种基于网格和简单规则的计算方法.尽管这是一种简单的模型,但其在模拟复杂过程(比如:生命现象,晶体生长和湍流)时往往能取得较好的结果.提出了一种由传统的二... 详细信息

关于雪花生长过程的计算机模拟已经受到了广泛关注.其中,元胞自动化模型是一种基于网格和简单规则的计算方法.尽管这是一种简单的模型,但其在模拟复杂过程(比如:生命现象,晶体生长和湍流)时往往能取得较好的结果.提出了一种由传统的二维模型扩展而来的三维雪花晶体生长方法.计算机模拟结果显示提出的方法能够更精确地模拟出三维雪花的晶体化过程.

关键词：雪花晶体近似模式元胞自动化模型

Laser ion source for heavy ion inertial fusion

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Matter and Radiation at Extremes 2018年第2期3卷 61-66页

作者： masahiro Okamura Collider-Accelerator Department Brookhaven National LaboratoryBuilding 930UptonNY 11973USA

The proposed heavy ion inertial fusion(HIF)scenarios require ampere class low charge state ion beams of heavy *** laser ion source(LIS)is recognized as one of the promising candidates of ion beam providers,since it can deliver high brightness heavy ion beams to *** design of LIS for the HIF depends on the accelerator structure and accelerator complex following the *** this article,we discuss the specifications and design of an appropriate LIS assuming two major types of the accelerators:radio frequency(RF)high quality factor cavity type and non-resonant induction core *** believe that a properly designed LIS would satisfy the requirements of both types,while some issues need to be verified experimentally.

关键词： Inertial fusion Accelerator Ion source Laser ablation Heavy ion source

On a Relation between the Universal Teichmu¨ller Space and the Grunsky Operator

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Acta Mathematica Sinica,English Series 2014年第4期30卷 591-600页

作者： masahiro YANAGISHITA Departments in Fundamental Science and Engineering Waseda University

Being a Strebel point gives a sufficient condition for that the extremal Beltrami coefficient is uniquely determined in a Teichmiiller equivalence class. We consider how Strebel points are characterized. In this paper, we will give a new characterization of Strebel points in a certain subset of the universal Teichmfiller space by a property of the Grunsky operator.

关键词： Quasiconformal mappings Strebel points Grunsky inequalities

An Inverse Problem for Maxwell's Equations in Anisotropic Media

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Chinese Annals of Mathematics,Series B 2007年第1期28卷 35-54页

作者： masahiro YAMAMOTO Graduate School of Mathematical Sciences The University of Tokyo 3-8-1 Komaba Meguro Tokyo 153Japan

The authors consider Maxwell＇s equations for an isomagnetic anisotropic and inhomogeneous medium in two dimensions, and discuss an inverse problem of determining the permittivity tensor （ε1,ε2,ε2,ε3 ） and the permeability μ in the constitutive relations from a finite number of lateral boundary measurements. Applying a Carleman estimate, the authors prove an estimate of the Lipschitz type for stability, provided that ε1,ε2,ε3,μ satisfy some a priori conditions.

关键词： Anisotropic media Inverse problem Maxwell's equations Carleman estimate Lipschitz stability