检索结果-南通市图书馆

Chemical functionalization of chitosan biopolymer and chitosan-magnetite nanocomposite with sulfonic acid for acid-catalyzed reactions

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2021年第11期34卷 154-161页

作者： Majid Masteri-Farahani Samaneh Shahsavarifar Research Institute of Green chemistry Faculty of ChemistryKharazmi UniversityTehranIran

Chemical functionalization of chitosan biopolymer and chitosan-magnetite nanocomposite was performed with sulfonic acid functional groups to achieve new solid acid *** sulfonic acid functional groups were created through the ring opening nucleophilic reaction of amine groups of chitosan with 1,4-butane *** transform infrared spectroscopy(FT-IR)and X-ray photoelectron spectroscopies(XPS)verified the successful sulfonic acid functionalization of *** obtained sulfonic acid functionalized chitosan-magnetite nanocomposite showed superparamagnetic properties according to the vibrating sample magnetometry analysis and exhibited magnetic separation feature from dispersed *** adsorption-desorption analysis indicated the increase in surface area after formation of chitosan-magnetite nanocomposite and functionalization with sulfonic *** of the prepared solid acids exhibited high catalytic activities in the acid-catalyzed acetic acid esterification with n-butanol and benzaldehyde acetalization with ethylene glycol as model ***,they can be reused several times without considerable loss of their activities.

关键词： Chitosan Magnetite Nanostructure Sulfonic acid Catalysis Esterification

Corrosion Protection of Electro-Galvanized Steel by Green Conversion Coatings

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2007年第5期25卷 537-543页

作者： Mirghasem Hosseini Habib Ashassi-Sorkhabi Heshmat Allah Yaghobkhani Ghiasvand Electrochemistry Research Laboratory Physical Chemistry Department Chemistry Faculty University of Tabriz

A A cerium-based chemical conversion process was studied. First, zinc coating obtained from a free-cyanide alkaline bath, with derivative of imidazol with new brightener, was investigated, zinc-plated steel specimens were treated with a solution of 50 mmol· L^-1 Ce（NO3 ）3 The corrosion behavior of bare and treated mild galvanized steel was evaluated during exposure to 0.5 mol · L^-1 NaCl for different immersion time, using Tafel polarization curves and electrochemical impedance spectroscopy （EIS） measurements. The surface morphology of the coating was studied using scanning electron microscopy （SEM）. The composition and chemical percent of the coating were examined by X-ray dispersion energy （EDAX）. The results of these measurements showed that the newly developed cerium-based conversion coating process was a promising candidate for replacing the conventional chromate treatments used at present for galvanized steel.

关键词： green coating free-cyanide alkaline bath EIS electro-galvanized rare earths

Construction of Nanophase Novel Coatings-Based Titanium for the Enhancement of Protein Adsorption

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2016年第3期29卷 243-252页

作者： Sahar A.Fadlallah Mohammed A.Amin Ghaida S.Alosaimi Materials and Corrosion Lab(MCL) Department of ChemistryFaculty of ScienceTaif University chemistry Department Faculty of ScienceCairo University chemistry Department Faculty of ScienceAin Shams University

In the recent years,biological nanostructures coatings have been incorporated into orthopedic and dental implants in order to accelerate osseointegration and reducing surgical *** the present work,chemical etching,anodization and metal doping surface modification methods were integrated in one strategy to fabricate innovative titanium surfaces denominated by titanium nanoporous,anodized titanium nanoporous,silver-anodized titanium nanoporous and gold-anodized titanium *** stability properties of nanostructures-coated surfaces were elucidated using electrochemical impedance spectroscopy（EIS） after 7 days of immersion in simulated biological *** and chemical compositions of new surfaces were characterized by scanning electron microscope and energy-dispersive X-ray *** EIS results and data fitting to the electrical equivalent circuit model demonstrated the influence of adsorption of bovine serum albumin on new surfaces as a function of protein *** process was described by the very well-known model of the Langmuir adsorption *** thermodynamic parameter DGADS（-50 to 59 kJ mol^（-1）） is calculated,which supports the instantaneous adsorption of protein from biological fluids to new surfaces and refers to their good ***,this study explores new surface strategy to gain new implants as a means of improving clinical outcomes of patients undergoing orthopedic surgery.

关键词： Titanium Nanoporous Surface modification Protein adsorption Electrochemical impedance spectroscopy(EIS)

Synthesis and Characterization of Soluble Polyester Based on Calixarene Dicarboxylic Acid with Tertiary Butyl Pendant Groups

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2014年第5期32卷 551-557页

作者： Hossein Mighani Hamed Tashakkorian Moein Mighani faculty of chemistry Golestan University faculty of chemistry Mazandaran University Department of Chemical Engineering Noshirvani University of Technology

A series of new polycalixesters （PCES） were synthesized by polyesterification of calixarene dicarboxylic acid derivatives having tertiary butyl pendant groups at the upper rim using five different diols. All polyesters were readily soluble in polar solvents such as NMP （N-methylpyrrolidone）, DMF （dimethylformamide）, DMSO （dimethylsulfoxide）, pyridine, THF （tetrahydrofurane）, HMPA （hexamethylenephosphoramide） and DMAC （dimethylacetamide）. The PCES were also partially soluble in TCE （tetrachloroethane） and ethanol and they were unsoluble in aceton. The glass transition temperatures of polyesters were between 80-184 ℃, the crystallinity temperatures of polyesters were between 130-212 ℃ and the melting temperatures of polyesters were between 185-234 ℃, as determined by differential scanning calorimeter （DSC）. The inherent viscosities of polyesters were obtained from 0.55 dL/mg to 0.61 dL/mg. The temperatures at 10% weight loss of polyesters ranged from 182 ℃ to 237 ℃. The temperatures at 25% weight loss of polyesters ranged from 258 ℃ to 331 ℃. The half weight loss （50%） temperatures of polyesters were among 315 ℃ to 371 ℃ and the char yields at 600 ℃ were determined within 13% to 22.3% in N2 atmosphere, as determined by thermo gravimetric analysis （TGA）. The polyester, PES3, has the higher melting point （234 ℃） and higher inherent viscosity （molecular weight） than the other polyesters.

关键词： Calixarene Polyester Thermal stability TGA DSC.

Composition and Physico-Chemical Properties of Meat from Capons Fed Cereals

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2013年第11期12卷 1953-1960页

作者： Olga Díaz Luisana Rodríguez Alexandr Torres ngel Cobos food Technology Division Department of Analytical ChemistryNutrition and Food ScienceFaculty of SciencesUniversity of Santiago de Compostela

Chemical composition, physico-chemical properties and fatty acid composition of breast and drumstick meat from capons （castrated male cockerels） fed cereals were studied. Three groups of capons were reared. One group was fed ad libitum the same commercial diet until the 4th mon of life. The last month of its life, the capons of this group were fed corn. The second and third group of capons were fed the same diet from caponization. The second group was fed mixture of corn （50%） and wheat （50%）. The third group of capons was fed 2/3 corn and 1/3 mixture of corn （50%） and barley （50%）. Capons were reared under free-range conditions and slaughtered at 150 d of age. Caponization was performed at 48 d. No signiifcant effects of feeding in chemical composition, pH, water holding capacity, drip and cooking losses and texture of the meat were observed. The meat of the third group （capons fed 83%corn） was more yellow and showed higher content of C18：2 than that of the other capons.

关键词： castrated male cockerel feeding meat quality fatty acids

Calculation of Hildebrand Solubility Parameters of Some Polymers Using QSPR Methods Based on LS-SVM Technique and Theoretical Molecular Descriptors

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2014年第5期32卷 587-594页

作者： Nasser Goudarzi M.Arab Chamjangali A.H.Amin faculty of chemistry Shahrood University of Technology

In this work, some chemometrics methods are applied for the modeling and prediction of the Hildebrand solubility parameter of some polymers. A genetic algorithm （GA） method is designed for the selection of variables to construct two models using the multiple linear regression （MLR） and least square-support vector machine （LS-SVM） methods in order to predict the Hildebrand solubility parameter. The MLR method is used to build a linear relationship between the molecular descriptors and the Hildebrand solubility parameter for these compounds. Then the LS-SVM method is utilized to construct the non-linear quantitative structure-activity relationship （QSAR） models. The results obtained using the LS-SVM method are then compared with those obtained for the MLR method; it was revealed that the LS-SVM model was much better than the MLR one. The root-mean-square errors of the training set and the test set for the LS-SVM model were 0.2912 and 0.2427, and the correlation coefficients were 0.9662 and 0.9518, respectively. This paper provides a new and effective method for predicting the Hildebrand solubility parameter for some polymers, and also reveals that the LS-SVM method can be used as a powerful chemometrics tool for the quantitative structure-property relationship （QSPR） studies.

关键词： Hildebrand solubility parameter Least square-support vector machine (LS-SVM) Quantitative structure- property relationship (QSPR) Multiple linear regression (MLR) Genetic algorithm (GA).

Interaction of TbCl_3 and lanthanide complexes with poly(N-vinylpyrrolidone)

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2014年第3期32卷 282-287页

作者： M.Karbowiak J.Cichos K.Buczko faculty of chemistry University of Wroc?aw

The interaction of TbC13 and lanthanide（Ⅲ） β-diketonate complexes with poly（N-vinylpyrrolidone）（PVP） polymer was studied using fluorescence spectroscopy. In the presence of PVP the emission of Tb3＋ in cthanolic solution of TbCl3 significantly in- creased owing to the excitation energy transfer from PVP to Tb3＋ ions, which was more efficient as compared to a direct excitation of the Tb3＋ 4f75d1 levels. In contrast, emission of NEt4Tb（hfa）4 and NEt4Eu（hfa）4 complexes was almost completely quenched in solu- tion containing PVP. The PVP bound both Ln3＋ ions and hfa ligands which caused decomposition of Ln-hfa complexes and switched off the excitation energy transfer from the ligand to the emitting Ln3＋ ion. The important role of hydrogen bonds in stabilization of in- teraction ofhfa ligands with PVP was indicated.

关键词： poly(N-vinylpyrrolidone) PVP lanthanide(Ⅲ) TbCl3 emission quenching rare earths

Efficient nonenzymatic hydrogen peroxide sensor in acidic media based on Prussian blue nanoparticles-modified poly(o-phenylenediamine)/glassy carbon electrode

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2016年第3期27卷 481-486页

作者： Reza Ojani Parisa Hamidi Jahan-Bakhsh Raoof Electroanalytical chemistry Research Laboratory Faculty of ChemistryUniversity of Mazandaran

The Prussian blue nanoparticles（PBNPs） were prepared by a self-assembly process, on a glassy carbon（GC） electrode modified with a poly（o-phenylenediamine）（Po PD） film. The stepwise fabrication process of PBNPs-modified Po PD/GCE was characterized by scanning electron microscopy（SEM） and electrochemical impedance spectroscopy. The prepared PBNPs showed an average size of 70 nm and a homogeneous distribution on the surface of modified electrodes. The PBNPs/Po PD/GCE showed adequate mechanical, electrochemical stability and good sensitivity in comparison with other PB based H2O2 sensors. The present modified electrode exhibited a linear response for H2O2 reduction over the concentration range of 1–58.22 mmol L ^-1with a detection limit of ca. 0.8 mmol L ^-1（S/N = 3）, and sensitivity of 3187.89 m A（mol L ^-1） ^-1cm ^-2using the amperometric method. This sensor was employed for the H2O2 determination in real sample and also exhibited good interference resistance and selectivity.

关键词： Self-assembly Prussian blue nanoparticles Hydrogen peroxide Sensor

Effect of Some Heterocyclic Derivatives on the Removal of Copper Ions from Wastewater by Cementation

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2004年第5期20卷 539-546页

作者： A.A.Taha M.G.Marei D.E.Abd El-khalek Department of chemistry Faculty of ScienceUniversity of AlexandriaAlexandriaEgyptDepartment of ChemistryFaculty of ScienceUniversity of AlexandriaAlexandriaEgyptDepartment of ChemistryFaculty of ScienceUniversity of AlexandriaAlexandriaEgypt

Removal of copper ions from copper sulphate solutions on a rotating zinc rod in absence and in presence of 3(2H)-furanones and 4H-pyran-4-one derivatives was investigated experimentally. Variables studied were initial copper ions concentration, rotational speed of the zinc rod, temperature and concentration of organic additives. It was found that cementation reaction is first order in presence and in absence of additives. Increasing concentration of initial copper ions, rotational speed of the zinc rod and temperature were found to increase the rate of cementation. In presence of organic additives an enhancement of the rate was observed, except in presence of methoxyfuranone the rate was found to decrease by an amount ranging from 11.74% to 33.79%. Rate acceleration or inhibition is associated mainly with changes in the structure of the additives as well as its concentration. The apparent activation energy for the cementation process in presence of different additives was estimated and was found to be ranged between 11.8 kJ/mol and 25.95 kJ/mol. These values suggest that the copper removal process in presence of these additives is controlled by diffusion. A scanning electron microscopy study of copper deposits obtained in presence of tolylfuranone, phenylpyrone and methoxyfuranone correlate with their behaviour during the kinetic study. Different reaction conditions and the physical properties of solutions were studied to obtain dimensionless correlation among all these parameters. It was found that on applying cementation reaction on a sample from industrial wastewater in presence of phenylpyrone about 91.9% of Cu2+ are removed.

关键词： Cementation of copper Furanone and pyrone derivatives