A new model for deformed carbon nanotubes using Green’s function

A new method for modeling and analysis of deformed carbon nanotubes (CNTs) using Green’s function, is presented in this paper, for the first time. Using the proposed method, a new circuit model is obtained for the deformation region of a deformed single-walled CNT (SWCNT), which the values of its elements depend on the type of deformation and also the deformation parameters such as the coupling matrices and the energy variations of deformation region. The comparison between the obtained results from the analysis of proposed model and the literature gives a good match which approves the accuracy and correctness of the proposed model.     

Enhanced properties of photovoltaic devices tailored with novel supramolecular structures based on reduced graphene oxide nanosheets grafted/functionalized with thiophenic materials

For verifying the influence of donor–acceptor supramolecules on photovoltaic properties, different hybrids were designed and used in organic solar cells. In this respect, reduced graphene oxide (rGO) was functionalization with 2‐thiophene acetic acid (rGO‐f‐TAA) and grafted with poly(3‐dodecylthiophene) (rGO‐g‐PDDT) and poly(3‐thiophene ethanol) (rGO‐g‐PTEt) to manipulate orientation of poly(3‐hexylthiophene) (P3HT) assemblies. Face‐on, edge‐on, and flat‐on orientations were detected for assembled P3HTs on rGO and its functionalized and grafted derivatives, respectively. Alteration of P3HT orientation from face‐on to flat‐on enhanced current density (J _sc), fill factor (FF), and power conversion efficiency (PCE) and thus J _sc = 7.11 mA cm^?2, FF = 47%, and PCE = 2.14% were acquired. By adding phenyl‐C71‐butyric acid methyl ester (PC71BM) to active layers composed of pre‐designed P3HT/rGO, P3HT/rGO‐f‐TAA, P3HT/rGO‐g‐PDDT, and P3HT/rGO‐g‐PTEt hybrids, photovoltaic characteristics further improved, demonstrating that supramolecules appropriately mediated in P3HT:PC71BM solar cells. Phase separation was more intensified in best‐performing photovoltaic systems. Larger P3HT crystals assembled onto grafted rGOs (95–143 nm) may have acted as convenient templates for the larger and more intensified phase separation in P3HT:PCBM films. The best performances were reached for P3HT:P3HT/rGO‐g‐PDDT:PCBM (J _sc = 9.45 mA cm^?2, FF = 54%, and PCE = 3.16%) and P3HT:P3HT/rGO‐g‐PTEt:PCBM (J _sc = 9.32 mA cm^?2, FF = 53%, and PCE = 3.11%) photovoltaic systems. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55 , 1877–1889     

Synthesis and characterization of new polynuclear bis-5-oxy-1H-tetrazoles

Different bis-phenols reacted with cyanogen bromide in the presence of triethylamine as base to give the corresponding bis-cyanates which were treated with sodium azide in acetone as solvent to produce new bis(5-oxy-1H-tetrazole) derivatives. One more bis-tetrazole derivative was synthesized by reaction of 5-(4-aminophenoxy)-1H-tetrazole with adipoyl chloride. The prepared compounds were characterized by usual spectroscopic techniques. Published in Russian in Zhurnal Organicheskoi Khimii, 2009, Vol. 45, No. 1, pp. 156–159. The text was submitted by the authors in English.     

Palladium Supported on Zinc Oxide Nanoparticles as Efficient Heterogeneous Catalyst for SuzukiMiyaura and Hiyama Reactions under Normal Laboratory Conditions

Nanoscale Pd supported on ZnO was prepared by a facile coprecipitation method. Pd/ZnO Nanoparticles were characterized by using XRD, TEM, SEM, XPS, BET specific surface area measurement, and thermogravimetric analysis. This catalyst was used as novel and excellent heterogeneous catalyst for ligand‐free C? C bond‐formation particularly in the synthesis of unsymmetrical biaryls by Suzuki? Miyaura and Hiyama cross‐coupling reactions under air atmosphere without use of any Ar or N₂ flow. The catalyst can be recovered and recycled several times without marked loss of activity.     

An Efficient Method for Chemoselective Reduction of Nitro Compounds Using Bimetallic Fe‐Ni NPs/H3PW12O40.×H2O System

The selective reduction of nitro compounds by treatment with bimetallic Fe‐Ni nanoparticles (NPs) and tungestophosphoric acid hydrate (H₃PW₁₂O₄₀.×H₂O) in H₂O is reported. The method has been applied to a broad range of nitro compounds with different sensitive functionalities, including halides, carbonyl, hydroxyl, aldehyde, methyl, acetyl, nitrile, and ester substituents with excellent yields. The reaction yielded single product in all cases with very high yield. The simple experimental procedure and easy purification make the protocol advantageous.     

A new method for the analysis of transmission property in carbon nanotubes using Green’s function

A new method for the analysis of electron transmission property in single-walled carbon nanotubes (SWCNTs) using Green’s function is presented in this paper for the first time. Using the proposed method, a new relation for the transmission function through a deformed SWCNT is obtained, which depends on the energy variations and the coupling matrices related to the mechanical deformations applied to the structure of CNT. The obtained new relation is explained by the presented results in the literature.     

Thermally stable polymers based on 1,3,4-oxadiazole rings

<正>In the present work,new thermally stable polymers containing 1,3,4-oxadiazole units have been synthesized through Huisgen reaction of the aromatic bis-tetrazole compounds with the aromatic/aliphatic bis-acid chlorides in pyridine as solvent.The obtained polymers are insoluble or slightly soluble in polar aprotic solvents such as DMSO and DMF. Thermal analyses of the polymers using DSC and TGA techniques showed that the polymers had improved thermal stabilities.The model reaction was also investigated and the resulting bis-l,3,4-oxadiazole compounds were characterized by conventional spectroscopic methods.     

One‐Pot,Three‐Component Synthesis of 1‐(2‐Hydroxyethyl)‐1H‐1,2,3‐triazole Derivatives by Copper‐Catalyzed 1,3‐Dipolar Cycloaddition of 2‐Azido Alcohols and Terminal Alkynes under Mild Conditions in Water

A safe, efficient, and improved procedure for the regioselective synthesis of 1‐(2‐hydroxyethyl)‐1H‐1,2,3‐triazole derivatives under ambient conditions is described. Terminal alkynes reacted with oxiranes and NaN₃ in the presence of a copper(I) catalyst, which is prepared by in situ reduction of the copper(II) complex 4 with ascorbic acid, in H₂O. The regioselective reactions exclusively gave the corresponding 1,4‐disubstituted 1H‐1,2,3‐triazoles in good to excellent yields. This procedure avoids the handling of organic azides as they are generated in situ, making this already powerful click process even more user‐friendly and safe. The remarkable features of this protocol are high yields, very short reaction times, a cleaner reaction profile in an environmentally benign solvent (H₂O), its straightforwardness, and the use of nontoxic catalysts. Furthermore, the catalyst could be recovered and recycled by simple filtration of the reaction mixture and reused for ten consecutive trials without significant loss of catalytic activity. No metal‐complex leaching was observed after the consecutive catalytic reactions.     

3D quantum mechanical simulation of square nanowire MOSFETs by using NEGF method

In order to investigate the specifications of nanoscale transistors, we have used a three dimensional (3D) quantum mechanical approach to simulate square cross section silicon nanowire (SNW) MOSFETs. A three dimensional simulation of silicon nanowire MOSFET based on self consistent solution of Poisson-Schrödinger equations is implemented. The quantum mechanical transport model of this work uses the non-equilibrium Green’s function (NEGF) formalism. First, we simulate a double-gate (DG) silicon nanowire MOSFET and compare the results with those obtained from nanoMOS simulation. We understand that when the transverse dimension of a DG nanowire is reduced to a few nanometers, quantum confinement in that direction becomes important and 3D Schrödinger equation must be solved. Second, we simulate gate-all-around (GAA) silicon nanowire MOSFETs with different shapes of gate. We have investigated GAA-SNW-MOSFET with an octagonal gate around the wire and found out it is more suitable than a conventional GAA MOSFET for its more I _on /I _off , less Drain-Induced-Barrier-Lowering (DIBL) and less subthreshold slope.     

Reactions on a solid surface. A simple, economical and efficient Friedel-Crafts acylation reaction over zinc oxide (ZnO) as a new catalyst

Zinc oxide (ZnO) brings about a rapid Friedel-Crafts acylation of a range of activated and unactivated aromatic compounds such as anisole and chlorobenzene with acid chlorides in solvent-free conditions at room temperature. The ZnO powder can be reused up to three times after simple washing with dichloromethane.