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21.
Alejandro Heredia Vincent Meunier Igor K. Bdikin José Gracio Nina Balke Stephen Jesse Alexander Tselev Pratul K. Agarwal Bobby G. Sumpter Sergei V. Kalinin Andrei L. Kholkin 《Advanced functional materials》2012,22(14):2996-3003
Ferroelectrics are multifunctional materials that reversibly change their polarization under an electric field. Recently, the search for new ferroelectrics has focused on organic and bio‐organic materials, where polarization switching is used to record/retrieve information in the form of ferroelectric domains. This progress has opened a new avenue for data storage, molecular recognition, and new self‐assembly routes. Crystalline glycine is the simplest amino acid and is widely used by living organisms to build proteins. Here, it is reported for the first time that γ‐glycine, which has been known to be piezoelectric since 1954, is also a ferroelectric, as evidenced by local electromechanical measurements and by the existence of as‐grown and switchable ferroelectric domains in microcrystals grown from the solution. The experimental results are rationalized by molecular simulations that establish that the polarization vector in γ‐glycine can be switched on the nanoscale level, opening a pathway to novel classes of bioelectronic logic and memory devices. 相似文献
22.
Dirac Cone Spin Polarization of Graphene by Magnetic Insulator Proximity Effect Probed with Outermost Surface Spin Spectroscopy 下载免费PDF全文
Seiji Sakai Sergei V. Erohin Zakhar I. Popov Satoshi Haku Takahiro Watanabe Yoichi Yamada Shiro Entani Songtian Li Pavel V. Avramov Hiroshi Naramoto Kazuya Ando Pavel B. Sorokin Yasushi Yamauchi 《Advanced functional materials》2018,28(20)
The effects of the proximity contact with magnetic insulator on the spin‐dependent electronic structure of graphene are explored for the heterostructure of single‐layer graphene (SLG) and yttrium iron garnet Y3Fe5O12 (YIG) by means of outermost surface spin spectroscopy using a spin‐polarized metastable He atom beam. In the SLG/YIG heterostructure, the Dirac cone electrons of graphene are found to be negatively spin polarized in parallel to the minority spins of YIG with a large polarization degree, without giving rise to significant changes in the π band structure. Theoretical calculations reveal the electrostatic interfacial interactions providing a strong physical adhesion and the indirect exchange interaction causing the spin polarization of SLG at the interface with YIG. The Hall device of the SLG/YIG heterostructure exhibits a nonlinear Hall resistance attributable to the anomalous Hall effect, implying the extrinsic spin–orbit interactions as another manifestation of the proximity effect. 相似文献
23.
Qian Liu Shohei Kumagai Sergei Manzhos Yingqian Chen Indunil Angunawela Masrur Morshed Nahid Krishna Feron Steven E. Bottle John Bell Harald Ade Jun Takeya Prashant Sonar 《Advanced functional materials》2020,30(34)
To achieve semiconducting materials with high electron mobility in organic field‐effect transistors (OFETs), low‐lying energy levels (the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO)) and favorable molecular packing and ordering are two crucial factors. Here, it is reported that the incorporation of pyridine and selenophene into the backbone of a diketopyrrolopyrrole (DPP)‐based copolymer produces a high‐electron‐mobility semiconductor, PDPPy‐Se. Compared with analogous polymers based on other DPP derivatives and selenophene, PDPPy‐Se features a lower LUMO that can decrease the electron transfer barrier for more effective electron injection, and simultaneously a lower HOMO that, however, can increase the hole transfer barrier to suppress the hole injection. Combined with thermal annealing at 240 °C for thin film morphology optimization to achieve large‐scale crystallite domains with tight molecular packing for effective charge transport along the conducting channel, OFET devices fabricated with PDPPy‐Se exhibit an n‐type‐dominant performance with an electron mobility (μe) as high as 2.22 cm2 V?1 s?1 and a hole/electron mobility ratio (μh/μe) of 0.26. Overall, this study demonstrates a simple yet effective approach to boost the electron mobility in organic transistors by synergistic use of pyridine and selenophene in the backbone of a DPP‐based copolymer. 相似文献
24.
Sergei E. Alexandrov Michael L. Hitchman Sarkis Shamlian 《Advanced functional materials》1993,2(6):301-312
In this paper we describe the growth of silicon nitride from nitrogen and silane for the first time by capacitively coupled remote PECVD. We report on the effect of process parameters on the composition and properties of the deposited films and we show that by adjustment of these parameters it is possible to produce high-quality material which could be of interest for electronic applications. Of particular note is that the growth rate is about one order of magnitude higher than any previously reported for nitride growth with remote PECVD using molecular nitrogen as the nitrogen source. We also discuss the mechanism of growth and propose that electron excitation of nitrogen and silane occurs in the gas phase, producing SiHx species which are adsorbed on the growing surface. The nitrogen is then incorporated into the layer by heterogeneous reaction. 相似文献
25.
Sergei Yakovenko 《Journal of Dynamical and Control Systems》2006,12(3):433-449
We give a simplified proof and an improvement of a recent theorem of A. Grigoriev, placing an upper bound for the number of
roots of linear combinations of solutions of systems of linear equations with polynomial or rational coefficients.
To Yulij Sergeevich Ilyashenko on his 60th birthday.
2000 Mathematics Subject Classification. 34C08, 34C10, 34M10.
Gershon Kekst professorial chair in Mathematics. 相似文献
26.
Alexei A. Kotov Sergei S. Bazylev Vladimir E. Adashev Aleksei S. Shatskikh Ludmila V. Olenina 《International journal of molecular sciences》2022,23(8)
The Y chromosome is one of the sex chromosomes found in males of animals of different taxa, including insects and mammals. Among all chromosomes, the Y chromosome is characterized by a unique chromatin landscape undergoing dynamic evolutionary change. Being entirely heterochromatic, the Y chromosome as a rule preserves few functional genes, but is enriched in tandem repeats and transposons. Due to difficulties in the assembly of the highly repetitive Y chromosome sequence, deep analyses of Y chromosome evolution, structure, and functions are limited to a few species, one of them being Drosophila melanogaster. Despite Y chromosomes exhibiting high structural divergence between even closely related species, Y-linked genes have evolved convergently and are mainly associated with spermatogenesis-related activities. This indicates that male-specific selection is a dominant force shaping evolution of Y chromosomes across species. This review presents our analysis of current knowledge concerning Y chromosome functions, focusing on recent findings in Drosophila. Here we dissect the experimental and bioinformatics data about the Y chromosome accumulated to date in Drosophila species, providing comparative analysis with mammals, and discussing the relevance of our analysis to a wide range of eukaryotic organisms, including humans. 相似文献
27.
28.
Daniel J. O’Shannessy Stephen M. Jackson Natalie C. Twine Bryan E. Hoffman Zoltan Dezso Sergei I. Agoulnik Elizabeth B. Somers 《International journal of molecular sciences》2013,14(7):13687-13703
Folate receptor alpha (FOLR1/FRA) is reported to be overexpressed in epithelial ovarian cancers (EOC), especially the serous histotype. Further, while dysregulation of the folate-dependent 1-carbon cycle has been implicated in tumorogenesis, little is known relative to the potential mechanism of action of FOLR1 expression in these processes. We therefore investigated the expression of FOLR1, other folate receptors, and genes within the 1-carbon cycle in samples of EOC, normal ovary and fallopian tube on a custom TaqMan Low Density Array. Also included on this array were known markers of EOC such as MSLN, MUC16 and HE4. While few differences were observed in the expression profiles of genes in the 1-carbon cycle, genes previously considered to be overexpressed in EOC (e.g., FOLR1, MSLN, MUC16 and HE4) showed significantly increased expression when comparing EOC to normal ovary. However, when the comparator was changed to normal fallopian tube, these differences were abolished, supporting the hypothesis that EOC derives from fallopian fimbriae and, further, that markers previously considered to be upregulated or overexpressed in EOC are most likely not of ovarian origin, but fallopian in derivation. Our findings therefore support the hypothesis that the cell of origin of EOC is tubal epithelium. 相似文献
29.
Victor V. Ivanov Sergei D. Kirik Alexander А. Shubin Irina A. Blokhina Victor M. Denisov Lilya А. Irtugo 《Ceramics International》2013,39(4):3843-3848
A saturated acidic aluminum chloride solution with a total composition of AlCl3·HCl·12H2O was obtained, and its behavior under thermal treatments was studied using thermogravimetry, differential scanning calorimetry and mass spectrometry techniques. The thermolysis solid products were characterized with XRD and SEM. Four stages of the thermolysis could be distinguished. Initially, the solution lost free water molecules, and an amorphous precipitate with an approximate composition AlCl3·HCl·12 H2O was obtained as a product. The precipitate released eight water molecules in the temperature range 390–425 K. Then, all chlorine atoms in the form of HCl and two water molecules were outgassed at 425–485 K. The product completely lost water up to 650 K. The crystallization of the solid begins with appearance of the phase γ-Al2O3 at 1073 K, and the final product, α-Al2O3, is observed at 1323 K. The application of the saturated trichloride solutions as a binder and a promoter for activated sintering of composite ceramics on the base of alumina was examined. 相似文献
30.
Garrett BC Dixon DA Camaioni DM Chipman DM Johnson MA Jonah CD Kimmel GA Miller JH Rescigno TN Rossky PJ Xantheas SS Colson SD Laufer AH Ray D Barbara PF Bartels DM Becker KH Bowen KH Bradforth SE Carmichael I Coe JV Corrales LR Cowin JP Dupuis M Eisenthal KB Franz JA Gutowski MS Jordan KD Kay BD Laverne JA Lymar SV Madey TE McCurdy CW Meisel D Mukamel S Nilsson AR Orlando TM Petrik NG Pimblott SM Rustad JR Schenter GK Singer SJ Tokmakoff A Wang LS Wettig C Zwier TS 《Chemical reviews》2005,105(1):355-390