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11.
报道了一个在聚乙二醇中由卤代芳烃合成不同二芳基硫化物的高效方法.在Cu催化剂作用下,无味、易得、稳定的Na2S2O3· 5H2O盐是有效的硫源. 相似文献
12.
Nadia Martinez Hadis Anahideh Jay M. Rosenberger Diana Martinez Victoria C. P. Chen Bo Ping Wang 《Journal of Global Optimization》2017,68(3):563-586
Multivariate adaptive regression spline (MARS) is a statistical modeling method used to represent a complex system. More recently, a version of MARS was modified to be piecewise linear. This paper presents a mixed integer linear program, called MARSOPT, that optimizes a non-convex piecewise linear MARS model subject to constraints that include both linear regression models and piecewise linear MARS models. MARSOPT is customized for an automotive crash safety system design problem for a major US automaker and solved using branch and bound. The solutions from MARSOPT are compared with those from customized genetic algorithms. 相似文献
13.
Ali Reza Ghiasvand Hadis Solaymani Nahid Heidari 《Journal of the Iranian Chemical Society》2017,14(5):1113-1118
Quercetin is a polyphenolic flavonoid found in many plants and is used as a nutritional supplement. It has been reported to have biological properties that may play an important role in the prevention of human diseases, such as cancer, cardiovascular diseases, diabetes, ulcer, cataract and allergies. In this research, solidified floating organic drop microextraction coupled to high-performance liquid chromatography was used to extract and determine quercetin in Rosa canina L., growing in different areas of Lorestan Province in Iran. The effect of important experimental variables such as type and volume of extracting organic solvent, extraction temperature and time, pH and effect of ionic strength on the extraction recovery was investigated and optimized. Under the optimum extraction conditions, a linear response was obtained over the range of 0.5–40 µg mL?1. Relative standard deviation (RSD%) and enrichment factor were found to be 3.4% and 230, respectively. The proposed method was applied successfully for the determination of quercetin in calycles and fruit of R. canina L. samples. The results showed good agreement compared with those obtained by a validated standard method. 相似文献
14.
Polarity control and residual strain in ZnO epilayers grown by molecular beam epitaxy on (0001) GaN/sapphire
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Md. Barkat Ullah Vitaliy Avrutin Si Qian Li Saikat Das Morteza Monavarian Mykyta Toporkov Ümit Özgür Pierre Ruterana Hadis Morkoç 《固体物理学:研究快报》2016,10(9):682-686
We report on the polarity control of ZnO grown by plasma assisted molecular beam epitaxy on Ga polar (0001) GaN/sapphire templates simply via the oxygen‐to‐Zn (VI/II) ratio during the growth of a thin nucleation layer at 300 °C. Following Zn pre‐exposure, the ZnO layers nucleated with low VI/II ratios (<1.5) exhibited Zn‐polarity. Those nucleated with VI/II ratios above 1.5, exhibited O‐polarity. Supported by scanning transmission electron microscopic imaging, we have unequivocally demonstrated that polarity inversion takes place without formation of any vertical inversion domains and within one monolayer of presumably non‐stoichiometric GaOx formed at the ZnO/GaN interface. A direct correlation between polarity and strain sign of ZnO layers has been found. The Zn‐polar ZnO layers were under tensile biaxial strain, whereas the O‐polar material exhibited compressive strain. Moreover, the amount of residual strain varied linearly with VI/II ratio used during the low‐temperature nucleation layer growth. Strain control with VI/II ratio has been explained by the potential formation of Zn interstitials. 相似文献
15.
Cover Picture: Polarity control and residual strain in ZnO epilayers grown by molecular beam epitaxy on (0001) GaN/sapphire (Phys. Status Solidi RRL 9/2016)
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16.
This article describes an efficient, simple, and clean method for the synthesis of α,α′-bis(arylidene, furylidene and cinnamylidene)cycloalkanones under solvent-free conditions. The cross-aldol condensation of cycloalkanones with aldehydes in the presence of silica-supported phosphorus pentoxide (P2O5/SiO2) or silicaphosphinoxide (silphox, [POCl3-n(SiO2)n]) as heterogeneous reagents produces the title compounds in good to excellent yields. 相似文献
17.
Shiravi Amir Hossein Shafiee Mojtaba Firoozzadeh Mohammad Bostani Hadis Bozorgmehrian Maryam 《Journal of Thermal Analysis and Calorimetry》2021,145(2):597-607
Journal of Thermal Analysis and Calorimetry - The convective heat transfer coefficient (CHTC) of a fluid is one of the most effective factors on the performance of a fluid in heat transfer... 相似文献
18.
Cemil Kayis Romualdo A. Ferreyra Congyong Zhu Vitaliy Avrutin Ümit Özgür Hadis Morkoç 《固体物理学:研究快报》2012,6(4):163-165
We report on the reliability of Inx Al1–xN/AlN/GaN‐based heterostructure field‐effect transistors (HFETs) fabricated on five different wafers with varying indium compositions (0.12 ≤ x ≤ 0.20) encompassing the tensile/compressive strain fields. All of the tested devices underwent high field on‐state stress at 20 V DC drain bias and zero gate bias for five hours. We monitored the drain current and low‐frequency noise (LFN) a priori and a posteriori the stress treatment to quantify device degradation. HFETs suffering tensile strain showed remarkably large degradation which manifested itself with up to 25 dB increase in noise power and up to 72% loss of drain current after stress. On the other hand, devices fabricated on compressively strained structures remained intact after stress, but they had about 30 dB higher pre‐stress noise‐power levels and about 50% lower drain‐current densities to begin with. The results show that the nearly lattice‐matched In0.17Al0.83N barrier exhibited very low degradation along with current density remaining high compared with the devices having barriers with lower or higher indium content. Our results suggest that the nearly‐lattice‐matched InAlN can be a good candidate for devices due to its relatively better reliability while maintaining a high current density. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
19.
Comparative study of acid yellow 119 adsorption onto activated carbon prepared from lemon wood and ZnO nanoparticles loaded on activated carbon
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Hadis Jamshidi Mehrorang Ghaedi Mohammad Mehdi Sabzehmeidani Ahmad Reza Bagheri 《应用有机金属化学》2018,32(2)
Activated carbon from lemon wood (AC) and ZnO nanoparticles loaded on activated carbon (ZnO‐NP‐AC) were prepared and their efficiency for effective acid yellow 199 (AY 199) removal under various operational conditions was investigated. The dependence of removal efficiency on variables such as AY 199 concentration, amount of adsorbent and contact time was optimized using response surface methodology and Design‐Expert. ZnO nanoparticles and ZnO‐NP‐AC were studied using various techniques such as scanning electron microscopy, X‐ray diffraction and energy‐dispersive X‐ray analysis. The optimum pH was studied using one‐at‐a‐time method to achieve maximum dye removal percentage. Small amounts of the proposed adsorbents (0.025 and 0.025 g) were sufficient for successful removal of AY 199 in short times (4.0 and 4.0 min) with high adsorption capacity (85.51 and 116.29 mg g?1 for AC and ZnO‐NPs‐AC, respectively). Fitting the empirical equilibrium data to several conventional isotherm models at optimum conditions indicated the appropriateness of the Langmuir model with high correlation coefficient (0.999 and 0.978 for AC and ZnO‐NPs‐AC, respectively) for representation and explanation of experimental data. Kinetics evaluation of experiments at various time intervals revealed that adsorption processes can be well predicted and fitted by pseudo‐second‐order and Elovich models. This study revealed that the combination of ZnO nanoparticles and AC following simple loading led to significant improvement in the removal process in short adsorption time which was enhanced by mixing the media via sonication. 相似文献
20.
Hadis Koolivand Alireza Sharifa Ehsan Chehrazi Mehdi Razzaghi Kashani Seyed Mohamad Reza Paran 《Polymer Science Series A》2016,58(5):801-809
The effect of graphene oxide (GO) nanosheets on the CO2/CH4 separation performance of a rubbery (poly(dimethylsiloxane), PDMS) as well as a glassy (polyetherimide, PEI) polymer is studied. Interfacial interactions between the nanosheets and both polymers are revealed by FTIR and SEM. The results of gas permeation through the membranes demonstrate that GO nanosheets enhance CO2/CH4 diffusivityselectivity of PEI and CO2/CH4 solubility-selectivities of the PEI and PDMS polymers, while diminish CO2/CH4 diffusivity-selectivity of PDMS. Furthermore, the possibility of overcoming the common tradeoff between CO2 permeability and CO2/CH4 selectivity of rubbery and glassy polymers by incorporating very low amounts of graphene oxide nanosheets is addressed. In other words, at 0.25 wt % GO loading, the PEI membrane shows simultaneous enhancement of CO2 permeability (16%) and CO2/CH4 selectivity (59%). Also, for the PDMS membrane simultaneous enhancement of CO2 permeability (29%) and CO2/CH4 selectivity (112%) is occurred at 0.5 wt % GO loading. Finally, the capability of the well known Nielsen model to predict the gas permeability behavior of the nanocomposites is investigated. 相似文献