排序方式: 共有89条查询结果,搜索用时 312 毫秒
31.
Gh. Alahyarizadeh H. Aghajani H. Mahmodi R. Rahmani Z. Hassan 《Optics & Laser Technology》2012,44(1):12-20
An analytical, visual and open source model based on solving the rate equations for InGaN/GaN single quantum well (QW) lasers has been carried out. In the numerical computations, the fourth-order Runge–Kutta method has been used for solving the differential rate equations. The rate equations which have been considered in this simulation include the two level rate equations for the well and separate confinement heterostructure (SCH) layers. We present a new and inexpensive modeling method with analytical, visual and open source capabilities to investigate and comprehend the QW laser characteristics such as time behavior of carriers in SCHs and QW, photon density, output power and gain, and also the output power versus current which presents the threshold current of the laser. The characteristics of the QW lasers, which include laser time response (P–t), turn-on delay time of lasing and output power–current (P–I) characteristic and related features such as threshold current and slope efficiency have been investigated. Our model accurately computes the P–t and P–I characteristics such as turn-on delay time, threshold current and slope efficiency, and also illustrates the effects of parameters such as the injection current and geometry. 相似文献
32.
β-Cyclodextrin (β-CD) supramolecule was found to be a convenient, green and economical tool in one-pot synthesis of rhodanine scaffolds as a highly efficient mediating agent in aqueous media in which the reaction accelerated to complete in 15 min and room temperature. In this work, amines reacted with equimolar ratio of CS2 (not excess ratio of CS2) and then with activated acetylenes in the presence of β-CD in aqueous media. 相似文献
33.
Multicomponent synthesis of biologically and pharmaceutically interested α-aminophosphonates derived from different amines and aromatic aldehydes was catalysed by biodegradable and easily accessible cellulose sulphuric acid. The catalyst could be prepared by functionalisation of cellulose in a simple step. Cellulose sources are bioavailable and rich among the bio-compounds. 相似文献
34.
Dr. Asadollah Bafekry Prof. Catherine Stampfl Prof. S. Farjami Shayesteh 《Chemphyschem》2020,21(2):164-174
Using first-principles calculations we systematically investigate the atomic, electronic and magnetic properties of novel two-dimensional materials (2DM) with a stoichiometry C3N which has recently been synthesized. We investigate how the number of layers affect the electronic properties by considering monolayer, bilayer and trilayer structures, with different stacking of the layers. We find that a transition from semiconducting to metallic character occurs which could offer potential applications in future nanoelectronic devices. We also study the affect of width of C3N nanoribbons, as well as the radius and length of C3N nanotubes, on the atomic, electronic and magnetic properties. Our results show that these properties can be modified depending on these dimensions, and depend markedly on the nature of the edge states. Functionalization of the nanostructures by the adsorption of H adatoms is found induce metallic, half-metallic, semiconducting and ferromagnetic behavior, which offers an approach to tailor the properties, as can the application of strain. Our calculations give insight into this new family of C3N nanostructures, which reveal unusual electronic and magnetic properties, and may have great potential in applications such as sensors, electronics and optoelectronic at the nanoscale. 相似文献
35.
In this work, a new tridentate Schiff base dioxo-molybdenum(VI) complex immobilized on silica-coated magnetic nanoparticles (MoO25CML–Fe3O4@SiO2) has been synthesized and characterized using different techniques such as FTIR, TGA, AAS, ICP–AES, XRD, VSM, EDX and SEM analyses. The catalytic activity of synthesized complex was examined in the oxidation of various sulfides in the presence of H2O2 as cheap, green and eco-friendly oxidant. This catalytic system provides high conversion and selectivity toward either sulfoxides or sulfones under different conditions. Also, the nanocatalyst could be easily separated and regenerated from reaction media by external magnet and could be reused for ten times without significant loss of the activity and selectivity. 相似文献
36.
A new, efficient, and environmentally benign protocol for the one-pot, four-component synthesis of 2,2-dimethyl-13-phenyl-2,3-dihydro-1H-indazolo[2,1-b]phthalazine-1,6,11(13H)-trione by condensation of phthalic anhydride, hydrazinium hydroxide, aromatic aldehydes, and dimedone catalyzed by Ce(SO4)2·4H2O as an ecofriendly catalyst with high catalytic activity and reusability at 125 °C under solvent-free conditions is reported. The reaction proceeds to completion within 5-10 min in 71-95% yield. To the best of our knowledge, this new procedure provides the first example of an efficient synthetic method for 2H-indazolo[2,1-b]phthalazine-1,6,11(13H)-trione via a four-component reaction. 相似文献
37.
Elaheh Mosaddegh Mohammad Reza Islami Asadollah Hassankhani 《Arabian Journal of Chemistry》2012,5(1):77-80
ZrOCl2·8H2O was found to be an efficient and recyclable catalyst for the reaction of aromatic aldehydes with dimedone to afford 1,8-dioxo-1,2,3,4,5,6,7,8-octahydroxanthenes under solvent-free conditions. Short reaction time, excellent yields and simple work-up are the advantages of this procedure. The interaction obtained from XRD studies was shown that the catalyst loses H2O during the reaction but it did not affect catalytic activity of the catalyst and the catalyst could be reused several times. 相似文献
38.
Majid Soolaki Iraj Mahdavi Nezam Mahdavi-Amiri Reza Hassanzadeh Aydin Aghajani 《Applied Mathematical Modelling》2012
The airline industry is under intense competition to simultaneously increase efficiency and satisfaction for passengers and profitability and internal system benefit for itself. The boarding process is one way to achieve these objectives as it tends itself to adaptive changes. In order to increase the flying time of a plane, commercial airlines try to minimize the boarding time, which is one of the most lengthy parts of a plane’s turn time. To reduce boarding time, it is thus necessary to minimize the number of interferences between passengers by controlling the order in which they get onto the plane through a boarding policy. Here, we determine the passenger boarding problem and examine the different kinds of passenger boarding strategies and boarding interferences in a single aisle aircraft. We offer a new integer linear programming approach to reduce the passenger boarding time. A genetic algorithm is used to solve this problem. Numerical results show effectiveness of the proposed algorithm. 相似文献
39.
In this paper, we investigate the existence of unique continuous linear extension for linear correspondences. We also give some results on cosine families of linear correspondences. 相似文献
40.
In this work, catalytic performance of a molybdenum Schiff base complex‐supported magnetic support as a nanocatalyst was evaluated for the preparation of 2‐amino‐4H‐benzo[h]chromenes through one‐pot, three component reactions of 1‐naphthol, various aldehydes, and malononitrile under solvent‐free conditions. A promising greener and eco‐friendly method with a short reaction time, high yield of products, and simple work‐up procedure was achieved. The nanocatalyst could be easily separated and regenerated from reaction media by an external magnet and reused at least seven consecutive times with small drops in its catalytic performance. 相似文献