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排序方式: 共有329条查询结果,搜索用时 15 毫秒
81.
Mahboubeh Rostami Ahmad R. Khosropour Valiollah Mirkhani Iraj Mohammadpoor-Baltork Majid Moghadam Shahram Tangestaninejad 《Journal of the Iranian Chemical Society》2014,11(5):1493-1501
Di[1,6-bis(3-methylimidazolium-1-yl)hexane] decatangstate ([C6(MIm)2]2W10O32) was found to be a novel, powerful and effective catalyst for the preparation of N-benzoylglycine carbamides as derivatives of AT-130 via one-pot multicomponent reaction performed under microwave irradiations. The products were obtained in high to excellent yields, thus providing a unique strategy to the large-scale synthesis of these compounds. 相似文献
82.
83.
Dr. Hajar Baguia Prof. Gwilherm Evano 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(41):e202200975
Perfluoroalkylated (hetero)arenes represent an extremely important family of molecules commonly utilized in many areas such as medicinal chemistry, agrochemistry and material sciences. Due to their unique properties, they have attracted significant interest from synthetic chemists and various methods have been developed for their synthesis. Among them, the direct perfluoroalkylation of C(sp2)−H bonds in (hetero)arenes is one of the most attractive and straightforward ones, provided that it proceeds with high levels of regioselectivity. In this review article, a comprehensive overview of advances in this field is presented, with a special focus on the reaction mechanisms involved in these transformations and their regioselectivity. All methods available have been classified according to the nature of the perfluoroalkyl chain introduced, trifluoromethylation reactions being overviewed in a separate section, and to the nature of the reagents/catalysts required. 相似文献
84.
Shadpour Mallakpour Amir Abdolmaleki Maryam Rostami 《Colloid and polymer science》2015,293(2):545-553
85.
Parvaneh Shabanzadeh Rubiyah Yusof Kamyar Shameli Hajar Khanehzaei 《Research on Chemical Intermediates》2016,42(4):2831-2843
This research was to apply the combination of the particle swarm optimization method and artificial neural network training with the aim of building a quantitative model to forecast the size of copper nanoparticles (Cu-NPs) prepared in sodium alginate. Sodium alginate, sodium hydroxide, copper sulfate, hydrazinium hydroxide, and ascorbic acid were used as stabilizer, pH moderator, copper precursor, reducing agent, and antioxidant, respectively. The results showed that the different sizes of Cu-NPs were obtained by changing these functions. Meaning that by increasing the amount of sodium alginate and or increase the volume of hydrazine hydrate, particle sizes of Cu-NPs were reduced. Other variables had the opposite effects due to the increase of the size of the Cu-NPs. The prediction results were remarkably in agreement with the experimental data with a correlation coefficient of 0.99 and a mean square error of 0.0058. 相似文献
86.
Free convection heat transfer along an isothermal vertical wavy surface was studied experimentally and numerically. A Mach-Zehnder
Interferometer was used in the experiment to determine the local heat transfer coefficients. Experiments were done for three
different amplitude–wavelength ratios of α = 0.05, 0.1, 0.2 and the Rayleigh numbers ranging from Ra
l
= 2.9 × 105 to 5.8 × 105. A finite-volume based code was developed to verify the experimental study and obtain the results for all the amplitude–wavelength
ratios between α = 0 to 0.2. It is found that the numerical results agree well with the experimental data. Results indicate
that the frequency of the local heat transfer rate is the same as that of the wavy surface. The average heat transfer coefficient
decreases as the amplitude–wavelength ratio increases and there is a significant difference between the average heat transfer
coefficients of the surface with α = 0.2 and those surfaces with α = 0.05 and 0.1. The experimental data are correlated
with a single equation which gives the local Nusselt number along the wavy surface as a function of the amplitude–wavelength
ratio and the Rayleigh number. 相似文献
87.
In this paper, we investigate the optical bistability induced by optical nonlinearity in a compact parallel array of micro-ring resonators with radius of 5 μm. Due to the nature of perfect light confinement in this structure, resonance and accumulation process in a ring resonator and optical nonlinear effects, are observable even at small optical power (a few milliwatts). Different optical applications such as all-optical switching, optical memory devices, logic gates and modulators are possible, due to optical bistability in a ring resonator. Using alternative semiconductor compounds, instead of silicon that have weak nonlinear optical properties, we improve the performance of ring-resonator based devices. Here we use a polymer cladding layer with negative thermo-optic coefficient. Using this structure we can eliminate the temperature created nonlinearity which is a very slow process. Therefore, the switching speed increases from a few MHz to several tens of GHz. By plotting the transfer function of the resonator, a hysteresis loop is observed in a few milliwatts. Although, using a ring resonator array the bandwidth reduces, however, the width of the hysteresis loop and resolution between both steady state increases. 相似文献
88.
In this paper we propose a framework to enhance light extraction efficiency in white organic light emitting diodes (WOLED) using photonic crystal (PhC) structures sandwiched between indium tin oxide (ITO, nITO = 1.8+0.01i) and glass (nglass = 1.51) substrate, according to the high refractive index contrast of these two layers almost 50% of the generated light inside WOLED gets trapped in the mentioned interface. The main purpose of this article is to suggest a method to intentionally optimize PhC structures to reduce total internal reflections (TIR) happening at ITO/glass interface. Here three different patterns are considered including rectangular, hexagonal and circular lattices. Using Finite Difference Time Domain (FDTD) method and the presented framework for choosing structural parameters the portion of 50% trapped light in ITO was reduced to 20% which is a large enhancement in extraction efficiency of WOLED. Also far-field results before and after adding PhCs are investigated. 相似文献
89.
Ahmad Abbasi Hajar Roshan-Shekalgourabi Dawood Hassanzadeh-Lelekaami 《Czechoslovak Mathematical Journal》2014,64(2):327-333
Let R be a commutative Noetherian ring with identity and I an ideal of R. It is shown that, if M is a non-zero minimax R-module such that dim Supp H I i (M) ? 1 for all i, then the R-module H I i (M) is I-cominimax for all i. In fact, H I i (M) is I-cofinite for all i ? 1. Also, we prove that for a weakly Laskerian R-module M, if R is local and t is a non-negative integer such that dim Supp H I i (M) ? 2 for all i < t, then Ext R j (R/I,H I i (M)) and Hom R (R/I,H I t (M)) are weakly Laskerian for all i < t and all j ? 0. As a consequence, the set of associated primes of H I i (M) is finite for all i ? 0, whenever dim R/I ? 2 and M is weakly Laskerian. 相似文献
90.
A nonenzymatic electrochemical sensor for glucose and fructose was fabricated that contained a glassy carbon electrode modified with a copper oxide (CuO)/multiwalled carbon nanotube (MWCNT) nanocomposite. The electrochemical properties of the CuO/MWCNT‐modified glassy carbon electrode were investigated. Two distinguishable anodic peaks were observed around 0.30 and 0.44 V corresponding to the oxidation of glucose and fructose, respectively, at the surface of the modified electrode. The detection limits for glucose and fructose were both 0.04 mmol/L. The sensor was used to simultaneously determine the concentrations of glucose and fructose in hydrolyzed sucrose samples, and to measure glucose in blood serum samples, demonstrating its potential as a nonenzymatic carbohydrate sensor. 相似文献