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https://www.readbyqxmd.com/read/28644638/ferroelectric-domain-patterning-controlled-schottky-junction-state-in-monolayer-mos_-2
#1
Zhiyong Xiao, Jingfeng Song, David K Ferry, Stephen Ducharme, Xia Hong
We exploit scanning-probe-controlled domain patterning in a ferroelectric top layer to induce nonvolatile modulation of the conduction characteristic of monolayer MoS_{2} between a transistor and a junction state. In the presence of a domain wall, MoS_{2} exhibits rectified I-V characteristics that are well described by the thermionic emission model. The induced Schottky barrier height Φ_{B}^{eff} varies from 0.38 to 0.57 eV and is tunable by a SiO_{2} global back gate, while the tuning range of Φ_{B}^{eff} depends sensitively on the conduction-band-tail trapping states...
June 9, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28644492/electronic-properties-of-blue-phosphorene-graphene-and-blue-phosphorene-graphene-like-gallium-nitride-heterostructures
#2
Minglei Sun, Jyh-Pin Chou, Jin Yu, Wencheng Tang
Blue phosphorene (BlueP) is a graphene-like phosphorus nanosheet which was synthesized very recently for the first time [Nano Lett., 2016, 16, 4903-4908]. The combination of electronic properties of two different two-dimensional materials in an ultrathin van der Waals (vdW) vertical heterostructure has been proved to be an effective approach to the design of novel electronic and optoelectronic devices. Therefore, we used density functional theory to investigate the structural and electronic properties of two BlueP-based heterostructures - BlueP/graphene (BlueP/G) and BlueP/graphene-like gallium nitride (BlueP/g-GaN)...
June 23, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28641426/assessment-of-two-hybrid-van-der-waals-density-functionals-for-covalent-and-non-covalent-binding-of-molecules
#3
Kristian Berland, Yang Jiao, Jung-Hoon Lee, Tonatiuh Rangel, Jeffrey B Neaton, Per Hyldgaard
Two hybrid van der Waals density functionals (vdW-DFs) are developed using 25% Fock exchange with (i) the consistent-exchange vdW-DF-cx functional [K. Berland and P. Hyldgaard, Phys. Rev. B 89, 035412 (2014)] and (ii) with the vdW-DF2 functional [K. Lee et al., Phys. Rev. B 82, 081101 (2010)]. The ability to describe covalent and non-covalent binding properties of molecules is assessed. For properties related to covalent binding, atomization energies (G2-1 set), molecular reaction energies (G2RC set), and ionization energies (G21IP set) are benchmarked against experimental reference values...
June 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28640628/oriented-gold-nanorods-and-gold-nanorod-chains-within-smectic-liquid-crystal-topological-defects
#4
Brigita Rožič, Jérôme Fresnais, Celine Molinaro, Joseph Calixte, Shivakumar Umadevi, Stephanie Lau-Truong, Nordin Felidj, Tobias Kraus, Fabrice Charra, Vincent Dupuis, Torsten Hegmann, Celine Fiorini-Debuisschert, Bruno Gallas, Emmanuelle Lacaze
We show that the use of oriented linear arrays of smectic A defects, the so-called smectic oily streaks, enables the orientation of gold nanorods (GNRs) for a large range of GNR diameters, ranging from 7 to 48 nm, and for various ligands. For the small GNRs it enables oriented end-to-end small chains of GNRs when the density is increased from around 2 GNRs/μm(2) to around 6 GNRs/μm(2). We have characterized the orientation of single GNRs by spectrophotometry and two-photon luminescence (TPL). A strongly anisotropic absorption of the composites and an on-off switching of GNR luminescence, both controlled by incident light polarization, are observed, revealing an orientation of the GNRs mostly parallel to the oily streaks...
June 22, 2017: ACS Nano
https://www.readbyqxmd.com/read/28640515/carbon-dots-as-fillers-inducing-healing-self-healing-and-anticorrosion-properties-in-polymers
#5
Cheng Zhu, Yijun Fu, Changan Liu, Yang Liu, Lulu Hu, Juan Liu, Igor Bello, Hao Li, Naiyun Liu, Sijie Guo, Hui Huang, Yeshayahu Lifshitz, Shuit-Tong Lee, Zhenhui Kang
Self-healing is the way by which nature repairs damage and prolongs the life of bio entities. A variety of practical applications require self-healing materials in general and self-healing polymers in particular. Different (complex) methods provide the rebonding of broken bonds, suppressing crack, or local damage propagation. Here, a simple, versatile, and cost-effective methodology is reported for initiating healing in bulk polymers and self-healing and anticorrosion properties in polymer coatings: introduction of carbon dots (CDs), 5 nm sized carbon nanocrystallites, into the polymer matrix forming a composite...
June 22, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28640302/influence-of-substituents-on-dna-and-protein-binding-of-cyclometalated-ir-iii-complexes-and-anticancer-activity
#6
Sujay Mukhopadhyay, Roop Shikha Singh, Rajendra Prasad Paitandi, Gunjan Sharma, Biplob Koch, Daya Shankar Pandey
Synthesis of terpyridyl based ligands 3-([2,2':6',2''-terpyridin]-4'-yl)-7-methoxy-2-(methylthio)-quinolone, (L1); 3-([2,2':6',2''-terpyridin]-4'-yl)-6-methoxyquinolin-2(1H)-one, (L2); 3-([2,2'-:6',2''-terpyridin]-4'-yl)-6-methylquinolin-2(1H)-one (L3) and cyclometalated iridium(iii) complexes [[Ir(ppy)2L1](+)PF6(-) (1), [Ir(ppy)2L2](+)PF6(-) (2), [Ir(ppy)2L3](+)PF6(-) (3) (2-phenylpyridine = Hppy)] involving these ligands has been described. The ligands L1-L3 and complexes 1-3 have been thoroughly characterized by elemental analyses, spectral studies (IR, (1)H, (13)C NMR, UV/vis and fluorescence) ESI-MS, and the structure of 3 has been unambiguously authenticated by single crystal X-ray analyses...
June 22, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28639401/van-der-waals-epitaxial-growth-of-atomic-layered-hfs2-crystals-for-ultrasensitive-near-infrared-phototransistors
#7
Lei Fu, Feng Wang, Bin Wu, Nian Wu, Wei Huang, Hanlin Wang, Chuanhong Jin, Lin Zhuang, Jun He, Lei Fu, Yunqi Liu
As a member of the group IVB transition metal dichalcogenides (TMDs) family, hafnium disulfide (HfS2 ) is recently predicted to exhibit higher carrier mobility and higher tunneling current density than group VIB (Mo and W) TMDs. However, the synthesis of high-quality HfS2 crystals, sparsely reported, has greatly hindered the development of this new field. Here, a facile strategy for controlled synthesis of high-quality atomic layered HfS2 crystals by van der Waals epitaxy is reported. Density functional theory calculations are applied to elucidate the systematic epitaxial growth process of the S-edge and Hf-edge...
June 22, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28639323/molecular-interactions-of-dioxins-and-dlcs-with-the-xenosensors-pxr-and-car-an-in-silico-risk-assessment-approach
#8
Garima Verma, Mohemmed Faraz Khan, Mohammad Shaquiquzzaman, Wasim Akhtar, Mymoona Akhter, Syed Misbahul Hasan, Mohammad Mumtaz Alam
Dioxins and dioxin-like compounds (DLCs) are known to cause endocrine disruption in humans and animals. Being lipophilic xenobiotic chemicals, they can be easily absorbed into the biological system from the surrounding environments, thereby causing various health dysfunctions. In the present study, a total of 100 dioxins and DLCs were taken, and their binding pattern was assessed with the xenosensors pregnane X receptor (PXR) and constitutive androstane receptor (CAR) in comparison with the corresponding known inhibitors and a well-studied endocrine disrupting xenobiotic, bisphenol A (BPA)...
June 22, 2017: Journal of Molecular Recognition: JMR
https://www.readbyqxmd.com/read/28638905/thermal-stability-and-thermal-conductivity-of-phosphorene-in-phosphorene-graphene-van-der-waals-heterostructures
#9
Qing-Xiang Pei, Xiaoliang Zhang, Zhiwei Ding, Ying-Yan Zhang, Yong-Wei Zhang
Phosphorene, a new two-dimensional (2D) semiconducting material, has attracted tremendous attention recently. However, its structural instability under ambient conditions poses a great challenge to its practical applications. A possible solution for this problem is to encapsulate phosphorene with more stable 2D materials, such as graphene, forming van der Waals heterostructures. In this study, using molecular dynamics simulations, we show that the thermal stability of phosphorene in phosphorene/graphene heterostructures can be enhanced significantly...
June 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28638769/deeper-insight-into-the-six-step-domino-reaction-of-aldehydes-with-malononitrile-and-evaluation-of-antiviral-and-antimalarial-activities-of-the-obtained-bicyclic-products
#10
Christina M Bock, Gangajji Parameshwarappa, Simon Bönisch, Walter Bauer, Corina Hutterer, Maria Leidenberger, Oliver Friedrich, Manfred Marschall, Barbara Kappes, Andreas Görling, Svetlana B Tsogoeva
The straightforward and efficient synthesis of complex aza- and carbobicyclic compounds, which are of importance for medicinal chemistry, is a challenge for modern chemical methodology. An unprecedented metal-free six-step domino reaction of aldehydes with malononitrile was presented in our previous study to provide, in a single operation, these bicyclic nitrogen-containing molecules. Presented here is a deeper investigation of this atom-economical domino process by extending the scope of aldehydes, performing post-modifications of domino products, applying bifunctional organocatalysts and comprehensive NMR studies of selected domino products...
June 2017: ChemistryOpen
https://www.readbyqxmd.com/read/28637365/insight-into-the-c-f-bond-mechanism-of-molecular-analogs-for-antibacterial-drug-design
#11
Junna Liu, Biyu Lv, Huaqing Liu, Xin Li, Weiping Yin
The activities of biological molecules usually rely on both of intra-molecular and intermolecular interactions between their function groups. These interactions include interonic attraction theory, Van der Waal's forces and the function of geometry on the individual molecules, whether they are naturally or synthetic. The purpose of this study was to evaluate the antibacterial activity of C-F bond compound using combination of experiments verification and theoretical calculation. We target on the insect natural products from the maggots of Chrysomyis megacephala Fabricius...
June 21, 2017: Natural Product Research
https://www.readbyqxmd.com/read/28633817/computational-study-of-state-equation-effect-on-single-acoustic-cavitation-bubble-s-phenomenon
#12
Kaouther Kerboua, Oualid Hamdaoui
Many models have been established to study the evolution of the bubble dynamics and chemical kinetics within a single acoustic cavitation bubble during its oscillation. The content of the bubble is a gas medium that generates the evolution of a chemical mechanism governed by the internal bubble conditions. These gases are described by a state equation, linking the pressure to the volume, temperature and species amounts, and influencing simultaneously the dynamical, the thermal and the mass variation in the cavitation bubble...
September 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28633399/the-interfacial-character-of-antibody-paratopes-analysis-of-antibody-antigen-structures
#13
Minh N Nguyen, Mohan R Pradhan, Chandra Verma, Pingyu Zhong
Summary: In this study, computational methods are applied to investigate the general properties of antigen engaging residues of a paratope from a non-redundant dataset of 403 antibody-antigen complexes to dissect the contribution of hydrogen bonds, hydrophobic, van der Waals contacts and ionic interactions, as well as role of water molecules in the antigen-antibody interface. Consistent with previous reports using smaller datasets, we found that Tyr, Trp, Ser, Asn, Asp, Thr, Arg, Gly, His contribute substantially to the interactions between antibody and antigen...
June 15, 2017: Bioinformatics
https://www.readbyqxmd.com/read/28632421/novel-urushiol-derivatives-as-hdac8-inhibitors-rational-design-virtual-screening-molecular-docking-and-molecular-dynamics-studies
#14
Hao Zhou, Chengzhang Wang, Tao Deng, Ran Tao, Wenjun Li
Three series of novel urushiol derivatives were designed by introducing a hydroxamic acid moiety into the tail of an alkyl side chain and substituents with differing electronic properties or steric bulk onto the benzene ring and alkyl side chain. The compounds' binding affinity towards HDAC8 was screened by Glide docking. The highest-scoring compounds were processed further with molecular docking, MD simulations and binding free energy studies to analyze the binding modes and mechanisms. Ten compounds had Glide scores of -8...
June 20, 2017: Journal of Biomolecular Structure & Dynamics
https://www.readbyqxmd.com/read/28631480/fully-transparent-quantum-dot-light-emitting-diode-with-a-laminated-top-graphene-anode
#15
Li Yao, Xin Fang, Wei Gu, Wenhao Zhai, Yi Wan, Xixi Xie, Wanjin Xu, Xiaodong Pi, Guangzhao Ran, Guogang Qin
A new method to employ graphene as top electrode was introduced, and based on that, fully transparent quantum dot light emitting diodes (T-QLEDs) were sucessfully fabribated through a lamination process. We adopted the widely used wet transfer method to transfer bilayer graphene (BG) on polydimethylsiloxane/polyethylene terephthalate (PDMS/PET) substrate. The sheet resistance of graphene reduced to ~540 Ω/□ through transferring BG for 3 times on the PDMS/PET. The T-QLED has an inverted device structure of glass/Indium tin oxide (ITO)/ZnO nanoparticles (NPs)/(CdSSe/ZnS quantum dots (QDs))/ 1,1-bis[(di-4-tolylamino)phenyl] cyclohexane (TAPC)/MoO3/ graphene/PDMS/PET...
June 20, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28631123/modeling-solubility-of-co2-hydrocarbon-gas-in-ionic-liquid-emim-fap-using-aspen-plus-simulations
#16
Bishwadeep Bagchi, Sushmita Sati, Vidyasagar Shilapuram
The Peng-Robinson equation of state with quadratic van der Waals (vdW) mixing rule model was chosen to perform the thermodynamic calculations in Flash3 column of Aspen Plus to predict the solubility of CO2 or any one of the hydrocarbons (HCs) among methane, ethane, propane, and butane in an ionic liquid 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([emim][FAP]). Bubble point pressure, solubility, bubble point temperature, fugacity, and partial molar volume at infinite dilution were obtained from the simulations, and enthalpy of absorption, Gibbs free energy of solvation, and entropy change of absorption were estimated by thermodynamic relations...
June 19, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28630925/buckyball-sandwiches
#17
Rasim Mirzayev, Kimmo Mustonen, Mohammad R A Monazam, Andreas Mittelberger, Timothy J Pennycook, Clemens Mangler, Toma Susi, Jani Kotakoski, Jannik C Meyer
Two-dimensional (2D) materials have considerably expanded the field of materials science in the past decade. Even more recently, various 2D materials have been assembled into vertical van der Waals heterostacks, and it has been proposed to combine them with other low-dimensional structures to create new materials with hybridized properties. We demonstrate the first direct images of a suspended 0D/2D heterostructure that incorporates C60 molecules between two graphene layers in a buckyball sandwich structure...
June 2017: Science Advances
https://www.readbyqxmd.com/read/28630922/flexible-ferroelectric-element-based-on-van-der-waals-heteroepitaxy
#18
Jie Jiang, Yugandhar Bitla, Chun-Wei Huang, Thi Hien Do, Heng-Jui Liu, Ying-Hui Hsieh, Chun-Hao Ma, Chi-Yuan Jang, Yu-Hong Lai, Po-Wen Chiu, Wen-Wei Wu, Yi-Chun Chen, Yi-Chun Zhou, Ying-Hao Chu
We present a promising technology for nonvolatile flexible electronic devices: A direct fabrication of epitaxial lead zirconium titanate (PZT) on flexible mica substrate via van der Waals epitaxy. These single-crystalline flexible ferroelectric PZT films not only retain their performance, reliability, and thermal stability comparable to those on rigid counterparts in tests of nonvolatile memory elements but also exhibit remarkable mechanical properties with robust operation in bent states (bending radii down to 2...
June 2017: Science Advances
https://www.readbyqxmd.com/read/28630901/stable-anchoring-chemistry-for-room-temperature-charge-transport-through-graphite-molecule-contacts
#19
Alexander V Rudnev, Veerabhadrarao Kaliginedi, Andrea Droghetti, Hiroaki Ozawa, Akiyoshi Kuzume, Masa-Aki Haga, Peter Broekmann, Ivan Rungger
An open challenge for single-molecule electronics is to find stable contacts at room temperature with a well-defined conductance. Common coinage metal electrodes pose fabrication and operational problems due to the high mobility of the surface atoms. We demonstrate how molecules covalently grafted onto mechanically robust graphite/graphene substrates overcome these limitations. To this aim, we explore the effect of the anchoring group chemistry on the charge transport properties of graphite-molecule contacts by means of the scanning tunneling microscopy break-junction technique and ab initio simulations...
June 2017: Science Advances
https://www.readbyqxmd.com/read/28628313/tunneling-kinetics-and-non-adiabatic-proton-coupled-electron-transfer-in-proteins-the-effect-of-electric-fields-and-anharmonic-donor-acceptor-interactions
#20
Bridget Salna, Abdelkrim Benabbas, Douglas Russo, Paul M Champion
A proper description of proton donor-acceptor (D-A) distance fluctuations is crucial for understanding tunneling in proton-coupled electron transport (PCET). The typical harmonic approximation for the D-A potential results in a Gaussian probability distribution, which does not appropriately reflect the electronic repulsion forces that increase the energetic cost of sampling shorter D-A distances. Because these shorter distances are the primary channel for thermally activated tunneling, the analysis of tunneling kinetics depends sensitively on the inherently anharmonic nature of the D-A interaction...
June 19, 2017: Journal of Physical Chemistry. B
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