排序方式: 共有131条查询结果,搜索用时 15 毫秒
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Hatice Kaplan Can 《高分子科学杂志,A辑:纯化学与应用化学》2016,53(1):26-33
The binary copolymerization of maleic anhydride (MA) and N-vinyl caprolactam (VCL) or considered as acceptor (A)?donor (D) monomer systems were used (MA:VCL) 50:50 in BPO (0.5%) as an initiator at 70°C under nitrogen atmosphere. The functional copolymers, having a combination of rigid/flexible linkages and an ability of complex-formation with interlayered surface of organo-silicate, and their nanocomposites have been synthesized. Interlamellar in situ complex-radical copolymerization of intercalated monomer complexes of MA and VCL undergoes with stearyl amine surface modified montmorillonite (O-MMT) and monomer mixtures. Charge transfer complex formation was followed and identified by UV-Vis-NIR spectroscopy. Equilibrium constant (KAD) molar absorption coefficient (?AD)) of the complex were determined by the Benesi-Hildebrand, Scott and Ketaalar equations respectively. The results show that copolymerization of MA:VCL system was preceded via alternating copolymerization mechanism. Obtained functional alternating copolymer and copolymer/O-MMT nanostructures were characterized by XRD and TEM. 相似文献
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Transition Metal Chemistry - New double-armed benzo-15-crown-5 compound (L) was successfully synthesized from 4’,5’-bis(bromethyl)benzo-15-crown-5 with 2,2’-dipyridylamine. The... 相似文献
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Janin T. Offenloch Marvin Gernhardt Dr. James P. Blinco Dr. Hendrik Frisch Dr. Hatice Mutlu Prof. Dr. Christopher Barner-Kowollik 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(15):3700-3709
Catalyst-free and bond-forming light-induced reactions have seen an unprecedented renaissance in the realm of soft matter materials science due to their efficiency, spatio-temporal controllability and, sometimes, photoreversible nature. However, many of these reactions rely on the application of high energy UV light that can cause photo-degradation and is inapplicable in biological environments. If up-conversion systems or two-photon processes are to be avoided, strategies for red-shifting catalyst-free ligation technology are critically required. This Concept article introduces the reader to recent methods that lead to efficient, catalyst-free visible-light-induced ligation chemistry based on polyaromatic substituted photoreactive compounds—pyrene and anthracene—and, furthermore, emphasizes the broad and facile applicability of these molecules in polymeric material design. Concomitantly, we highlight that a careful action plot analysis of photochemical reactivity can provide deep insights into reactivity patterns, far beyond those suggested by the absorption spectrum. Indeed, we suggest that an action plot analysis is necessary for the evaluation of any photochemical system and its response to structural chemical changes. 相似文献
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Staining of tissue is a significant process in histotechnology and staining techniques are used in the examination and diagnosis of diseases. The increase of international awareness for the environment, ecology, and health directed people to reduce toxic effluents and stop usage of dangerous chemical dyes. The present trend throughout the world is shifting towards to use of natural products over their synthetic alternatives. Therefore, in this study, the dyeing ability of alkanet plant on the cells of unstained sections taken from Wistar rat liver was investigated. The extract of Alkanna tinctoria contain naphthaquinone group of dyestuff. Chemical characterization of A. tinctoria extract was performed with HPLC-TOF/MS and UV spectra analysis, respectively. Different metal salts were used in the staining processes in order to obtain different colors. In the staining of without adding mordant (metal salt) to the extract, pale brown staining was obtained in the cytoplasm. Light pink color was obtained with the addition of CuSO4 mordant. Dark pink-red color was achieved by adding alum, and also NiSO4 was added for light purple staining. The staining of cytoplasm of different cells in liver tissue was achieved successfully with the extract of A. tinctoria and different colors were obtained using various mordants. 相似文献
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Yelda Bingöl Alpaslan Nevin Süleymanoğlu Emin Öztekin Ferda Erşahin Erbil Ağar Şamil Işık 《Journal of chemical crystallography》2010,40(11):950-956
Abstract
The molecular and crystal structure of the title compound, C14H11Cl2NO, has been determined by X-ray single crystal diffraction technique. The compound crystallizes in the orthorhombic, space group Pbca with unit cell dimensions a = 7.5537(10) ?, b = 11.5518(13) ?, c = 29.760(4) ?, M r = 280.14, V = 2596.8(6) ?3, Z = 8, R 1 = 0.065 and wR 2 = 0.191. The title compound exists in the enol–imine tautomeric form with a strong intramolecular O–H···N hydrogen bond. The dihedral angle between the two benzene rings is 37.66(15)°. The asymmetric unit in the crystal structure contains only one neutral molecule. Calculational studies were performed by using AM1, PM3, PM6 semi-empirical and DFT methods. Geometry optimizations of compound have been carried out by using three semi-empirical methods and DFT method and bond lengths, bond and torsion angles of title compound have been determined. Dipole moments (Debye) and the energy parameters of compound (kcal/mol) were calculated by using above mentioned calculation methods. Atomic charge distribution has been obtained from AM1, PM3, PM6 and DFT. In order to determine conformational flexibility on the molecule, molecular energy profile of the title compound was obtained with respect to the selected torsion angle T(N1–C7–C1–C2), which is varied from −180° to +180° in every 10 via PM3 semi-empirical method. 相似文献37.
Hatice Boylan Nils-Peter Skoruppa 《Abhandlungen aus dem Mathematischen Seminar der Universit?t Hamburg》2010,80(2):213-226
We derive an explicit formula for Hecke Gauss sums of quadratic number fields. As an immediate consequence we obtain a quadratic
reciprocity law in quadratic number fields which generalizes the classical one given by Hecke. The proofs use, apart from
the well-known formulas for ordinary Gauss sums, only elementary algebraic manipulations. 相似文献
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Geometry is one of the disciplines children involve within early years of their lives. However, there is not much information about geometry education in Turkish kindergarten classes. The current study aims to examine teachers’ perspectives on teaching geometry in kindergarten classes. The researchers inquired about teachers’ in-class experiences in geometry and asked a series of questions such as “what are the benchmarks in your kindergarten class?”; “what kind of tools and materials you use to teach geometry in your class?”; “what shape do you teach first in your kindergarten class?”; “what do you expect to hear when you asked your students ‘what is square’?”; “how do you teach rectangular?”. The study utilized one of the qualitative research methods, namely phenomenography, to collect the data and analyze the data. The study involved with eight kindergarten teachers who work in different schools in central Kutahya, Turkey. The researchers collected data by conducting face-to-face half-structured interviews. The findings of this phenomenographic research showed that kindergarten teachers have some difficulties in teaching geometry and have lack of knowledge and skills in teaching geometry in kindergarten classes. 相似文献
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Use of surfactants to remove water-based inks from plastic film: effect of calcium ion concentration and length of surfactant hydrophobe 总被引:1,自引:0,他引:1
Hatice?GecolEmail author John?F.?Scamehorn Sherril?D.?Christian Brian?P.?Grady Fred?E.?Riddell 《Colloid and polymer science》2004,283(2):154-163
Effective plastic film deinking could permit the reuse of recycled polymer to produce clear film, reduce solid waste for landfills, reduce raw material demand for polymer production, and aid process economics. In this study, the deinking of a commercial polyethylene film printed with water-based ink was studied using surfactants in the presence of hardness ions (calcium ions) at various pH levels. The electrostatic properties of ink particles in a washing bath were also investigated. Synthetic anionic surfactant or fatty acid soap in the presence of calcium ions at alkaline pH levels was found to be nearly as effective at deinking as cationic, nonionic, or amphoteric surfactants alone. However, adding calcium ions decreases the deinking effectiveness of cationic, nonionic, and amphoteric surfactants. Increasing the length of the ionic surfactant hydrophobe enhances deinking. Zeta potential measurements showed that water-based ink particles in water reach the point of zero charge (PZC) at a pH of about 3.6, above which ink particles are negatively charged, so cationic surfactant tends to adsorb better on the ink than anionic surfactant above the PZC in the absence of calcium. As the cationic surfactant concentration is varied between 0.005 and 25 mM, the zeta potential of the ink particles reverses from negative to positive owing to adsorption of cationic surfactant. For anionic surfactants, added calcium probably forms a bridge between the negatively charged ink and the negatively charged surfactant head groups, which synergizes adsorption of the surfactant and aids deinking. In contrast, calcium competes for adsorption sites with cationic and nonionic surfactants, which inhibits deinking. All the surfactants studied here disperse ink particles effectively in the washing bath above pH 3 except for the ethoxylated amine surfactant. 相似文献
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Hatice Yildirim 《Phosphorus, sulfur, and silicon and the related elements》2020,195(6):516-522
AbstractA set of bis(arylthio) substituted 5,8-quinolinedione derivatives were synthesized and investigated for their in vitro antimicrobial effect. The antibacterial and antifungal activities of 6,7-bis(arylthio)-5,8-quinolinedione (4a–f) and 6,7-bis(arylthio)-2-methyl-5,8-quinolinedione (5a–f) were evaluated against four gram-negative bacteria, three gram-positive bacteria, and three fungi strains. The bis(methoxyarylthio) 5,8-quinolinedione analogs presented better activity against especially gram-positive bacteria compared to bis(halogenarylthio) 5,8-quinolinedione analogs. Bis(3-methoxyarylthio) 5,8-quinolinedione (4e) had the same activity of the reference drug against Staphylococcus aureus. Bis(2-methoxyarylthio) 5,8-quinolinedione (4f) showed two-and-a half-fold better activity with 89.69?μM against Enterococcus faecalis, and two-fold better activity with 11.20?μM against Staphylococcus epidermidis. Bis(2-methoxyarylthio)-2-methyl-5,8-quinolinedione 5f exhibited five-fold higher antibacterial activity with 43.44?μM against E. faecalis and also eight-fold activity of the reference drug with 2.71?μM against S. epidermidis. 相似文献