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71.
We present the structural and dynamic nature of water ultraconfined in the quasi-two-dimensional nanopores of the highly disordered calcium-silicate-hydrate (C-S-H), the major binding phase in cement. Our approach is based on classical molecular simulations. We demonstrate that the C-S-H nanopore space is hydrophilic, particularly because of the nonbridging oxygen atoms on the disordered silicate chains which serve as hydrogen-bond acceptor sites, directionally orienting the hydrogen atoms of the interfacial water molecules toward the calcium-silicate layers. The water in this interlayer space adopts a unique multirange structure: a distorted tetrahedral coordination at short range up to 2.7 ?, a disordered structure similar to that of dense fluids and supercooled phases at intermediate range up to 4.2 ?, and persisting spatial correlations through dipole-dipole interactions up to 10 ?. A three-stage dynamics governs the mean square displacement (MSD) of water molecules, with a clear cage stage characteristic of the dynamics in supercooled liquids and glasses, consistent with its intermediate-range structure identified here. At the intermediate time scales corresponding to the β-relaxation of glassy materials, coincident with the cage stage in MSD, the non-Gaussian parameter indicates a significant heterogeneity in the translational dynamics. This dynamic heterogeneity is induced primarily because of the heterogeneity in the distribution of hydrogen bond strengths. The strongly attractive interactions of water molecules with the calcium silicate walls serve to constrain their motion. Our findings have important implications on describing the cohesion and mechanical behavior of cement from its setting to its aging. 相似文献
72.
Synthesis of bistriphenylamine‐ and benzodithiophene‐based random conjugated polymers for organic photovoltaic applications 下载免费PDF全文
Asli Cetin Cagla Istanbulluoglu Serife Ozdemir Hacioglu Sevki Can Cevher Levent Toppare Ali Cirpan 《Journal of polymer science. Part A, Polymer chemistry》2017,55(22):3705-3715
In this study, donor–acceptor random polymers containing benzotriazole acceptor and bistriphenylamine and benzodithiophene donors, P1 and P2 , were successfully synthesized by Stille coupling polymerization. The effect of bistriphenylamine moiety and thiophene π‐conjugated linker on electrochemical, spectroelectrochemical, and optical behaviors of the polymers were investigated. Optoelectronic properties and photovoltaic performance of the polymers were examined under the illumination of AM 1.5G, 100 mW cm?2. The polymers were characterized by cyclic voltammetry, UV‐Vis‐NIR absorption spectroscopy, gel permeation chromatography. HOMO/LUMO energy levels of P1 and P2 were calculated as ?5.47 eV/–3.41 eV and ?5.43 eV/–3.27 eV, respectively. Bulk heterojunction type solar cells were constructed using blends of the polymers (donor) and [6,6]‐phenyl C71 butyric acid methyl ester (PC71BM) (acceptor). Photovoltaic studies showed that the highest power conversion efficiency of these photovoltaic devices were recorded as 3.50% with open circuit voltage; 0.79 V, short circuit current; 9.45 mA cm?2, fill factor; 0.53 for P1 :PC71BM (1:2, w/w) in 3% o‐dichlorobenzene (o‐DCB) solution and 3.15% with open circuit voltage; 0.75 V, short circuit current; 8.59 mA cm?2, fill factor; 0.49 for P2 :PC71BM (1:2, w/w) in 2% chlorobenzene (CB) solution. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3705–3715 相似文献
73.
Bar Tercan Tuncer Hkelek Selen Bilge Bilgehan
zgü Zeynel Kl 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(6):o381-o383
The title compound, C15H16Cl4N5O2P3, is a cyclophosphazenic lariat (PNP‐pivot) ether with a spiro‐cyclic 12‐membered macrocyclic ligand containing two ether O and two N atoms; the phosphazene ring is nearly planar. In the macrocyclic ring, there is a four‐center (trifurcate) N—H⋯O/N—H⋯N hydrogen bond. The relative inner‐hole size of the macrocycle is estimated as approximately 0.95 Å. 相似文献
74.
Bilge Baytekin Dr. H. Tarik Baytekin Dr. Uwe Hahn Dr. Werner Reckien Dr. Barbara Kirchner Prof. Dr. Christoph A. Schalley Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(29):7139-7149
The mass spectrometric characterization of Fréchet‐type dendrons is reported. In order to provide the charges necessary for electrospray ionization, dendrons bearing an OH group at the focal point can be deprotonated and observed in the negative ion mode. Alternatively, the corresponding bromides can be converted to quaternary ammonium ions that can easily be detected in the positive mode. If the latter ions are subjected to collision‐induced dissociation experiments, a fragmentation cascade begins with the dissociation of the focal amine. The focal benzyl cation quickly decomposes in a fragmentation cascade from the focal point to the periphery until the peripheral benzyl (or naphthylmethyl) cations are formed. Five different mechanisms are discussed in detail, three of which can be excluded based on experimental evidence. The cascade fragmentation is reminiscent of self‐immolative dendrimers. 相似文献
75.
Bilge Inan Mohamed S. Osman Turgut Ak Dumitru Baleanu 《Mathematical Methods in the Applied Sciences》2020,43(5):2588-2600
In this paper, we combine the unified and the explicit exponential finite difference methods to obtain both analytical and numerical solutions for the Newell-Whitehead-Segel–type equations which are very important in mathematical biology. The unified method is utilized to obtain various solitary wave solutions for these equations. Numerical solutions of the specific case studies are investigated by using the explicit exponential finite difference method ensures the accuracy and reliability of the proposed scheme. After obtaining the approximate solutions, convergence analysis and error estimation (the error norms and absolute errors) are presented by comparing these results with the analytical obtained solutions and other methods in the literature through tables and graphs. The obtained analytical and numerical results are in good agreement. 相似文献
76.
N. Tuluolu S. Karadeniz A. Birkan Seluk S. Bilge Ocak 《Physica B: Condensed Matter》2007,400(1-2):168-174
In this work, the investigation of the interface states density and series resistance from capacitance–voltage (C–V) and conductance–voltage (G–V) characteristics in Au/SnO2/n-Si (MOS) structures prepared at various SnO2 layer thicknesses by spray deposition technique have been reported. It is fabricated five samples depending on deposition time. The thicknesses of SnO2 films obtained from the measurement of the oxide capacitance in the strong accumulation region for MOS Schottky diodes are 37, 79, 274, 401, and 446 Å, for D1, D2, D3, D4, and D5 samples, respectively. The C–V and G–V measurements of Au/SnO2/n-Si MOS structures are performed in the voltage range from −6 to +10 V and the frequency range from 500 Hz to 10 MHz at room temperature. It is observed that peaks in the forward C–V characteristics appeared because of the series resistance. It has been seen that the value of the series resistance Rs of samples D1 (47 Ω), D2 (64 Ω), D3 (98 Ω), D4 (151 Ω), and D5 (163 Ω) increases with increasing the oxide layer thickness. The interface state density Dit ranges from 2.40×1013 cm−2 eV−1 for D1 sample to 2.73×1012 cm−2 eV−1 for D5 sample and increases with increasing the oxide layer thickness. 相似文献
77.
Selva Bilge Leyla Karadurmus Esen Bellur Atici Ali Sınağ Sibel A. Ozkan 《Electroanalysis》2022,34(8):1318-1328
Ruxolitinib (RUX), a compound of the pyrrolopyrimidines class with activity as a tyrosine kinase inhibitory drug, is used to treat myelofibrosis. This study is reported for the detailed electrochemical behavior of RUX. The effects of supporting electrolyte, pH, and scanning rate on the peak potentials and currents of RUX were investigated by BDDE and GCE using different voltammetric techniques. Under optimum experimental conditions, calibration curves for RUX were obtained as 4 μM–80 μM and 1 μM–80 μM with a limit of detection (LOD) of 0.517 μM and 0.192 μM by the GCE and BDDE, respectively using DPV. 相似文献
78.
F. Sezer Senol Deniz Gokcen Eren Ilkay Erdogan Orhan Bilge Sener Ufuk Ozgen Randa Aldaba Ihsan Calis 《Molecules (Basel, Switzerland)》2021,26(7)
Cholinesterase (ChE) inhibition is an important treatment strategy for Alzheimer’s disease (AD) as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are involved in the pathology of AD. In the current work, ChE inhibitory potential of twenty-four natural products from different chemical classes (i.e., diosgenin, hecogenin, rockogenin, smilagenin, tigogenin, astrasieversianins II and X, astragalosides I, IV, and VI, cyclocanthosides E and G, macrophyllosaponins A-D, kokusaginin, lamiide, forsythoside B, verbascoside, alyssonoside, ipolamide, methyl rosmarinate, and luteolin-7-O-glucuronide) was examined using ELISA microtiter assay. Among them, only smilagenin and kokusaginine displayed inhibitory action against AChE (IC50 = 43.29 ± 1.38 and 70.24 ± 2.87 µg/mL, respectively). BChE was inhibited by only methyl rosmarinate and kokusaginine (IC50 = 41.46 ± 2.83 and 61.40 ± 3.67 µg/mL, respectively). IC50 values for galantamine as the reference drug were 1.33 ± 0.11 µg/mL for AChE and 52.31 ± 3.04 µg/mL for BChE. Molecular docking experiments showed that the orientation of smilagenin and kokusaginine was mainly driven by the interactions with the peripheral anionic site (PAS) comprising residues of hAChE, while kokusaginine and methyl rosmarinate were able to access deeper into the active gorge in hBChE. Our data indicate that similagenin, kokusaginine, and methyl rosmarinate could be hit compounds for designing novel anti-Alzheimer agents. 相似文献
79.
F. ?zdemir A. H. Bilge 《ARI - An International Journal for Physical and Engineering Sciences》1999,51(4):247-253
We show that the notion of strong self-duality of 2-forms in dimensions 2n, defined by the equality of the absolute values of the eigenvalues of the matrix of P with respect to an orthonormal basis (Bilge et al. 1996a), is equivalent to the self-duality in the Hodge sense of Pn/2 (used in Grossman et al. 1984) and to the equality *P=kPn-1 (used in Trautman 1977). We show that the octonionic instanton solution of Grossman et al. (1984), is uniquely determined from the minimality requirement of the second Pontrjagin number p2. 相似文献
80.
The Susceptible-Infected-Recovered (SIR) and Susceptible-Exposed-Infected-Recovered (SEIR) models describe the spread of epidemics in a society. In the typical case, the ratio of the susceptible individuals fall from a value S 0 close to 1 to a final value Sf , while the ratio of recovered individuals rise from 0 to Rf?=?1???Sf . The sharp passage from the level zero to the level Rf allows also the modeling of phase transitions by the number of “recovered” individuals R(t) of the SIR or SEIR model. In this article, we model the sol–gel transition for polyacrylamide–sodium alginate (SA) composite with different concentrations of SA as SIR and SEIR dynamical systems by solving the corresponding differential equations numerically and we show that the phase transitions of “classical” and “percolation” types are represented, respectively, by the SEIR and SIR models. 相似文献