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121.
Saiid A. Amer 《Transition Metal Chemistry》1991,16(2):152-154
Summary The reaction of 3,4-thiophenedicarboxaldehyde and 1,3-diaminopropane in EtOH gives a tetraazamacrocylic ligand (L). Two NiII complexes of L were prepared by a simple addition reaction, while other macrocyclic NiII complexes were prepared by metal-controlled condensation reactions between 3,4-thiophenedicarboxaldehyde and aliphatic diamines. On the basis of various physical properties, the complexes can be described as six co-ordinate pseudo-octahedral structures. Simple reactions led to the isolation of isothiocyanate and percholorate derivatives. 相似文献
122.
We report a new design for an acoustically resonant spectrophone well suited for intracavity operation with widely tunable
lasers. Operation with Brewster angle windows or in a windowless mode is possible, and high quality factors (560 and 509,
respectively) are achieved. Windowless operation permits continuous monitoring of ambient air. We discuss factors limiting
the sensitivity, ∼10−7 cm−1, and present a double chopping scheme capable of significantly reducing the acoustical background encountered in windowless
operation. The sensitivity of the spectrophone's performance to misalignment is also examined. 相似文献
123.
In this paper, an attempt has been made to develop a feasible procedure for the prediction of quality parameters of motor gasoline and to discriminate between the different adulterated motor gasoline samples using density values, distillation temperatures and Fourier transform infrared (FTIR) analyses along with multivariate calibrations without the need for using chromatographic separation or other expensive instruments such as an octane number analyser. Ten blend mixtures of regular and super motor gasoline were prepared in order to study density, distillation temperatures and FTIR spectra characteristics for each blend. Distillation temperatures for the pure and blend mixtures of regular and super motor gasoline at initial boiling point (IBP) to final boling point (FBP) at 5%Vol. interval were obtained. Accurate and complete distillation data on the uncontaminated fuel would be essential for comparison. Thirteen peaks of the absorbance at the wavenumbers: 434, 461, 484, 673, 694, 1030, 1086, 1217, 1231, 1460, 1497, 1606 and 3028 cm(-1) were chosen to perform the multivariate calibration. The results obtained were expected to be useful in determination and differentiation purposes, providing information on whether the density values, distillation temperatures and FTIR analyses along with multivariate method could be an appropriate feature for differentiating a particular pure motor gasoline sample from the others. The observed differences in the specific spectral bands are investigated and discussed. They have proven to be an effective combination in the pursuit of management's differentiation goals. 相似文献
124.
Íngrid Amer Cid Lenny Van Daele Peter Dubruel Kristiaan Neyts Filip Strubbe 《Electrophoresis》2023,44(3-4):417-430
Understanding the adsorption of polymers onto particles is crucial for many technological and biomedical applications. Even though polymer adsorption on particles is a dynamic process, most experimental techniques can only study the adsorption indirectly, in equilibrium and on the ensemble level. New analysis methods are required to overcome these limitations. We investigated the use of single-particle electrophoresis to study the adsorption kinetics of cationic polymers onto anionic particles and compared the resulting data to a theoretical model. In this approach, the electrophoretic mobility of single polystyrene (PS) particles, exposed to different concentrations of poly(2-guanidinoethyl methacrylate), was measured as a function of time. The polymer adsorption leads to an electrophoretic mobility change of the PS particle over time, from the initial negative value to a positive value at equilibrium. By fitting the kinetics data to the Langmuir model, the adsorption rate, desorption rate and equilibrium constant were determined. Finally, the adsorption kinetics of several other polymers was investigated. This showed that the presented technique enables direct analysis and comparison of the kinetics of polymer adsorption on the single-particle level. 相似文献
125.
In this article, the fractional derivatives in the sense of the modified Riemann-Liouville derivatives together with the modified simple equation method and the multiple exp-function method are employed for constructing the exact solutions and the solitary wave solutions for the nonlinear time fractional Sharma-Tasso- Olver equation. With help of Maple, we can get exact explicit 1-wave, 2-wave and 3-wave solutions, which include 1-soliton, 2-soliton and 3-soliton type solutions if we use the multiple exp-function method while we can get only exact explicit 1-wave solution including 1-soliton type solution if we use the modified simple equation method. Two cases with specific values of the involved parameters are plotted for each 2-wave and 3-wave solutions. 相似文献
126.
Yutao Yan Hassan Amer Thomas Rosenau Cordt Zollfrank Jörg Dörrstein Cornelia Jobst Tanja Zimmermann Jozef Keckes Stefan Veigel Wolfgang Gindl-Altmutter Jianzhang Li 《Cellulose (London, England)》2016,23(2):1189-1197
In order to produce dry and hydrophobic microfibrillated cellulose (MFC) in a simple procedure, its modification with alkyl ketene dimer (AKD) was performed. For this purpose, MFC was solvent-exchanged to ethyl acetate and mixed with AKD dissolved in the same solvent. Curing at 130 °C for 20 h under the catalysis of 1-methylimidazole yielded a dry powder. Scanning electron microscopy of the powder indicated loss in nanofibrillar structure due to aggregation, but discrete microfibrillar structures were still present. Water contact angle measurements of films produced from modified and unmodified MFC showed high hydrophobicity after AKD treatment, which persisted even after extraction with THF for 8 h. The hydrophobized MFC was characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance and X-ray analysis. In summary, strong indications for the presence of AKD on the surface of MFC before and after extraction with solvent were found, but only a very small amount of covalent β-ketoester linkages between the modification agent and cellulose was revealed. 相似文献
127.
A Facile One‐Pot Synthesis and Anticancer Evaluation of Novel Substituted 1,2‐Dihydropyridine and 1,2,3,4‐Tetrahydropyrimidine Analogues
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Ahmed Bari Mohammad Khalid Parvez Azmat Ali Khan Amer M. Alanazi Saeed Ali Syed Mohammed S. Al‐Dosari Abdulrahman M. Alobaid 《Journal of heterocyclic chemistry》2016,53(2):377-382
Current paper involves the one‐pot synthesis of various 1,2‐dihydropyridine and 1,2,3,4‐tetrahydropyrimidine analogues. The antitumor activity of the synthesized compounds has been carried out against various human cancer cell lines, and some of the analogues are found to be potent. 相似文献
128.
Reaction of phthalaldehydic acid with different substituted aniline as well as hydrazine derivatives
Sherine N. Khattab Seham Y. Hassan Ayman El‐Faham Abdel Moneim M. El Massry Adel Amer 《Journal of heterocyclic chemistry》2007,44(3):617-626
129.
Mohamed A. Ghanem Ibrahim S. El-Hallag Mabrook S. Amer Nouf H. Alotaibi 《Journal of Saudi Chemical Society》2021,25(7):101274
The alkaline water electrochemical splitting reactions need economical, very energetic, and durable catalysts. Here, a disordered mesoporous and highly defected titanium dioxide (dom-TiO2) electrocatalyst for the oxidation of hydroxide ion was prepared via ligand-assisted evaporation-induced self-assembly. The (dom-TiO2) electrocatalyst showed significant electrocatalytic performance for the oxidation of hydroxide ion compared to that of non-porous TiO2 (bare-TiO2) and highly-ordered hexagonal mesoporous (hm-TiO2) electrodes. The chemical and electrochemical parameters of the diffusion (D), concentration in the bulk (Cb), the number of transferred electrons (n), rate constant of heterogeneous electron transfer (ks), redox potential (E°), and homogeneous chemical rate constant (kc) for the oxidation of hydroxide ion reaction at the porous TiO2 electrodes were determined via the convolution–deconvolution voltammetry and competed against that of non-porous (bare-TiO2) and hm-TiO2 and catalysts. In addition to the effect of dom-TiO2 film thickness and the type of supporting electrolytes on the electrochemical parameters of the electrocatalytic oxidation of OH– ions have been estimated. The convolutive–deconvoluted results show that the dom-TiO2 electrode catalyst exhibits a superior reaction rate constant among the studied electrodes that depend on the film thickness and type of supporting electrolyte. 相似文献
130.
Dr. Amer Baniodeh Danny Wagner Dr. Yan Peng Hagen Kaemmerer Dr. Nicolas Leblanc Prof. Stefan Bräse Dr. Jean-Valére Naubron Dr. Christopher E. Anson Prof. Annie K. Powell 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(61):15103-15109
The {Fe2Dy2} butterfly systems can show single molecule magnet (SMM) behaviour, the nature of which depends on details of the electronic structure, as previously demonstrated for the [Fe2Dy2(μ3-OH)2(Me-teaH)2(O2CPh)6] compound, where the [N,N-bis-(2-hydroxyethyl)-amino]-2-propanol (Me-teaH3) ligand is usually used in its racemic form. Here, we describe the consequences for the SMM properties by using enantiopure versions of this ligand and present the first homochiral 3d/4 f SMM, which could only be obtained for the S enantiomer of the ligand for [Fe2Dy2(μ3-OH)2(Me-teaH)2(O2CPh)6] since the R enantiomer underwent significant racemisation. To investigate this further, we prepared the [Fe2Dy2(μ3-OH)2(Me-teaH)2(O2CPh)4(NO3)2] version, which could be obtained as the RS-, R- and S-compounds. Remarkably, the enantiopure versions show enhanced slow relaxation of magnetisation. The use of the enantiomerically pure ligand suppresses QTM, leading to the conclusion that use of enantiopure ligands is a “gamechanger” by breaking the cluster symmetry and altering the intimate details of the coordination cluster's molecular structure. 相似文献