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1.
Molecular Diversity - Nowadays, one of the principal causes of death in the world is cancer. A series of 2-azetidinones containing anthraquinone moiety with various substituents were synthesized... 相似文献
2.
Soltani Rad Mohammad Navid Behrouz Somayeh Mohammad-Javadi Mehdi Zarenezhad Elham 《Molecular diversity》2022,26(5):2503-2521
Molecular Diversity - The preparation, characterization and application of hydroxyapatite silica propyl bis aminoethoxy ethane cuprous complex (HASPBAEECC) as a novel hybrid nano-catalyst for... 相似文献
3.
The discrete least squares meshless (DLSM) method is extended in this paper for solving coupled bedload sediment transport equations. The mathematical formulation of this model consists of shallow water equations for the hydrodynamical component and an Exner equation expressing sediment continuity for the bedload transport. This method uses the moving least squares (MLS) function approximation to construct the shape functions and the minimizing least squares functional method to discretize the system of equations. The method can be viewed as a truly meshless method as it does not need any mesh for both field variable approximation and the construction of system matrices; it also provides the symmetric coefficient matrix. In the present work, several benchmark problems are studied and compared with the work of other researchers; the proposed method shows good accuracy, high convergence rate, and high efficiency, even for irregularly distributed nodes. At the end, a real test problem is performed to show and verify the main benefit and applicability of the proposed method to cope with complex geometry in practical problems. 相似文献
4.
Today, analyzing of sound pressure level and frequency is considered as an important index in human society. Sound experts believe that analyzing of these parameters can help us to better understanding of work environments. Sound measurements and frequency analysis did to fix the harmful frequency in all sections in Shiraz gas power plant with sound analyzer model BSWA 308. The sound pressure levels (LP) and the one and one-third octave band were continuously measured in A and C weighting networks and slow mode for time response. Excel 2013 and Minitab 18.1 software used for statistical calculations. Results analyzed by Minitab 18.1 software. The highest harmful frequency in Shiraz Gas Power Plant (SGPP) was 50 Hz with 115 dB. The sound pressure level (SPL) ranged from 45 dB to 120 dB in one-third octave band and weighting network C. The maximum sound pressure level was in Craft electricity generator with 105.3 dB and 67 Hz. Sound pressure level in surrounded environment was 120 dB. According to the results, in this industry the sound pressure level exceeded the Occupational Exposure Level of Iran (OEL). The value of sound pressure level were higher than the Standard of occupational health. SGPP consumes 47000 cubic meters of natural gas per hour to produce 100 MW (Mega Watt) of electricity. It is very high and it is not economical and cost effective. These numbers indicate that the power plant’s efficiency is low. It could be concluded that the noise pollution is an important issue in these industries. Moreover, SGPP produce noise with loss energy. Frequencies rotation at high sound pressure levels toward low frequencies were happened. 相似文献
5.
Binarization has always been a challenging problem in document image processing because of various types of degradation. In this paper, we present a nonlinear reaction–diffusion model for binarization of bleed-through document images, which is the Perona–Malik equation involving diffusion coefficient based on structure tensor along with a nonlinear reaction term. The Perona–Malik diffusion is utilized to selectively smooth document images with bleed-through removal. Meanwhile, the nonlinear reaction term takes the responsibility for the desired binarization. In order to solve our model numerically, we develop a parallel–series splitting algorithm by combining finite differencing with two kinds of splitting methods in the literature. Our algorithm is tested on seven publicly available datasets (DIBCO 2009 to 2014 and 2016). The experimental results show that our method averagely outperforms six relevant models for the nineteen document images with bleed-through in the DIBCO series datasets. 相似文献
6.
Mahdieh Darroudi Sara Ranjbar Mohammad Esfandiar Mahsima Khoshneviszadeh Mahshid Hamzehloueian Mehdi Khoshneviszadeh Yaghoub Sarrafi 《应用有机金属化学》2020,34(12):e5962
In the present work, novel 5-((1-benzyl-1,2,3-triazol-4-yl)methoxybenzylidene)-2-(arylamino)thiazol-4-one thiazolone incorporated triazole derivatives have been designed as tyrosinase inhibitors. The compounds were synthesized through click reaction in good yield. Moreover, the antityrosinas activity of the synthesized derivatives was evaluated. In the search for establishing a click copper-catalyzed azide/alkyne cycloaddition (CuAAC) reaction under strict conditions, in terms of a novel air-stable, a recyclable and efficient magnetic catalyst was planned for new triazole derivatives as a well-organized copper iodide supported on the functionalized Fe3O4@SiO2 core-shell (CuI/Fe3O4@SiO2(TMS-EDTA) nanoparticles). The engineered nanocatalyst synthesized for the first time and characterized by different methods, including FT-IR spectroscopy, XRD, FESEM, EDX, TEM, TGA, and BET analysis. The excellent catalytic performance in ethanol with high surface area (351.7 m2g−1) and short reaction time for diverse functional groups (120–200 min), no use of toxic solvents, reusability of the catalyst, and using eco-friendly conditions are the advantageous of this work. Moreover,the nanocatalyst can be used at least five times without any significant decrease in the yield of the reaction. The thiazolidine-triazole derivatives 9a , 9c , 9e , and 9 g showed promising tyrosinase inhibitory activity with IC50 values in the range of 5.90–9.81 μM. The compounds were found to be considerably more potent tyrosinase inhibitors than the reference inhibitor kojic acid (IC50 = 18.36 μM). 相似文献
7.
8.
Knowledge of the vibrational properties of nanoparticles is of fundamental interest since it is a signature of their morphology, and it can be utilized to characterize their physical properties. In addition, the vibration characteristics of the nanoparticles coupled with surrounding media and subjected to magnetic field are of recent interest. This paper develops an analytical approach to study the radial breathing-mode frequency of elastically confined spherical nanoparticles subjected to magnetic field. Based on Maxwell's equations, the nonlocal differential equation of radial motion is derived in terms of radial displacement and Lorentz's force. Bessel functions are used to obtain a frequency equation. The model is justified by a good agreement between the results given by the present model and available experimental and atomic simulation data. Furthermore, the model is used to elucidate the effect of nanoparticle size, the magnetic field and the stiffness of the elastic medium on the radial breathing-mode frequencies of several nanoparticles. Our results reveal that the effects of the magnetic field and the elastic medium are significant for nanoparticle with small size. 相似文献
9.
Milad Kazemnejadi Seyyedeh Ameneh Alavi G. Zinat Rezazadeh Mohammad Ali Nasseri Ali Allahresani Mohsen Esmaeilpour 《应用有机金属化学》2020,34(2):e5388
Cu(II) Schiff base complex supported on Fe3O4@SiO2 nanoparticles was employed as a magnetic nanocatalyst (nanocomposite) with a phase transfer functionality for the one-pot preparation of α-aminonitriles (Strecker reaction). The desired α-aminonitriles were obtained from the reaction of aromatic or aliphatic aldehydes, aniline or benzyl amine, NaCN, and 1.6 mol% of the catalyst in water at room temperature and good to excellent yields were obtained for all substrates. The catalyst was characterized analytically and instrumentally including Fourier-transform infrared spectroscopy, X-ray diffraction, thermogravimetric, nuclear magnetic resonance, energy-dispersive X-ray spectroscopy, inductively coupled plasma spectroscopy, vibrating-sample magnetometry analysis, dynamic light scattering, Brunauer–Emmett–Teller surface area, field emission scanning electron microscopy, and transmission electron microscopy analyses. The reaction mechanism was investigated, in which the performance of the catalyst as a phase transition factor seems to be probable. The catalyst showed high activity, high turnover frequency (TOF)s, significant selectivity, and fast performance toward the Strecker synthesis. The nanocatalyst can be readily and quickly separated from the reaction mixture with an external magnet and can be reused for at least seven successive reaction cycles without significant reduction in efficiency. 相似文献
10.
Pezhman Shiri 《应用有机金属化学》2020,34(5):e5600
The development of novel approaches for the preparation of small-sized heterocyclic products has remained an extremely attractive but challenging proposition. Copper has been known as one of the most applicable and significant transition metals utilized in the synthesis of organic products. A couple of factors such as high earth abundance and versatile catalysis resulted in the growth of copper-promoted synthesis of five-membered heterocyclic products. Utilizations such as making coins and electrical equipment express the importance of copper, as well. Here, a comprehensive overview of the copper-catalyzed synthesis of five-membered heterocyclic products is presented, focusing on the developments over the past 4 years. 相似文献