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排序方式: 共有250条查询结果,搜索用时 31 毫秒
1.
Crystallization of calcium carbonate (CC) in aqueous solutions by gas‐liquid diffusion procedure was investigated systematically in the presence of poly(4‐sulfonic acid diphenylamine)‐block‐poly(ethylene glycol) (PSDA‐b‐PEG), wherein the PSDA block is a polymeric zwitterion. PSDA‐b‐PEG was synthesized with the reaction of tosylated PEG and amine‐functionalized PSDA and was characterized by nuclear magnetic resonance. The parameters such as, block copolymer concentration, crystallization time and initial pH were considered as indicators of block copolymer's capability in controlling the morphology of CC particles. The particles were characterized by Fourier transform infrared, scanning electron microscopy, and X‐ray diffraction. The results suggest that PSDA‐b‐PEG is a suitable template to control the growth mechanism of CC to produce meso‐sized particles with different morphologies. POLYM. ENG. SCI., 59:96–102, 2019. © 2018 Society of Plastics Engineers 相似文献
2.
Emrah Sefik Abamor Ozlem Ayse Tosyali Melahat Bagirova Adil Allahverdiyev 《IET nanobiotechnology / IET》2018,12(8):1018
This study is the first to investigate the antileishmanial activities of Nigella sativa oil (NSO) entrapped poly‐ɛ ‐caprolactone (PCL) nanoparticles on Leishmania infantum promastigotes and amastigotes in vitro. NSO molecules with variable initial doses of 50, 100, 150, and 200 mg were successfully encapsulated into PCL nanoparticles identified as formulations NSO1, NSO2, NSO3, and NSO4, respectively. This process was characterised by scanning electron microscope, dynamic light scattering, Fourier transform infrared, encapsulation efficiency measurements, and release profile evaluations. The resulting synthetised nanoparticles had sizes ranging between 200 and 390 nm. PCL nanoparticles encapsulated 98% to 80% of initial doses of NSO and after incubation released approximately 85% of entrapped oil molecules after 288 h. All investigated formulations demonstrated strong antileishmanial effects on L. infantum promastigotes by inhibiting up to 90% of parasites after 192 h. The tested formulations decreased infection indexes of macrophages in a range between 2.4‐ and 4.1‐fold in contrast to control, thus indicating the strong anti‐amastigote activities of NSO encapsulated PCL nanoparticles. Furthermore, NSO‐loaded PCL nanoparticles showed immunomodulatory effects by increasing produced nitric oxide amounts within macrophages by 2–3.5‐fold in contrast to use of free oil. The obtained data showed significant antileishmanial effects of NSO encapsulated PCL nanoparticles on L. infantum promastigotes and amastigotes.Inspec keywords: antibacterial activity, drug delivery systems, nanofabrication, nitrogen compounds, nanomedicine, microorganisms, cellular biophysics, diseases, scanning electron microscopy, oils, polymers, biomedical materials, nanoparticles, encapsulation, Fourier transform infrared spectraOther keywords: encapsulation efficiency measurements, entrapped oil molecules, investigated formulations, NSO‐loaded PCL nanoparticles, Nigella sativa oil entrapped polycaprolactone nanoparticles, antileishmanial activities, poly‐ε‐caprolactone nanoparticles, scanning electron microscope, DLS, Fourier transform infrared, release profile evaluations, Leishmania infantum promastigotes, Leishmania infantum amastigotes, parasites, infection, infection indexes, macrophages, immunomodulatory effects, time 288.0 hour, time 192.0 hour, mass 50.0 mg, mass 100.0 mg, mass 150.0 mg, mass 200.0 mg, size 200.0 nm to 390.0 nm 相似文献
3.
4.
Ozlem Ozgun Gökhan Apaydin Mustafa Kuzuoglu Levent Sevgi 《Computer Physics Communications》2011,182(12):2638-2654
A MATLAB-based one-way and two-way split-step parabolic equation software tool (PETOOL) has been developed with a user-friendly graphical user interface (GUI) for the analysis and visualization of radio-wave propagation over variable terrain and through homogeneous and inhomogeneous atmosphere. The tool has a unique feature over existing one-way parabolic equation (PE)-based codes, because it utilizes the two-way split-step parabolic equation (SSPE) approach with wide-angle propagator, which is a recursive forward–backward algorithm to incorporate both forward and backward waves into the solution in the presence of variable terrain. First, the formulation of the classical one-way SSPE and the relatively-novel two-way SSPE is presented, with particular emphasis on their capabilities and the limitations. Next, the structure and the GUI capabilities of the PETOOL software tool are discussed in detail. The calibration of PETOOL is performed and demonstrated via analytical comparisons and/or representative canonical tests performed against the Geometric Optic (GO) + Uniform Theory of Diffraction (UTD). The tool can be used for research and/or educational purposes to investigate the effects of a variety of user-defined terrain and range-dependent refractivity profiles in electromagnetic wave propagation.
Program summary
Program title: PETOOL (Parabolic Equation Toolbox)Catalogue identifier: AEJS_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEJS_v1_0.htmlProgram obtainable from: CPC Program Library, Queen?s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 143 349No. of bytes in distributed program, including test data, etc.: 23 280 251Distribution format: tar.gzProgramming language: MATLAB (MathWorks Inc.) 2010a. Partial Differential Toolbox and Curve Fitting Toolbox requiredComputer: PCOperating system: Windows XP and VistaClassification: 10Nature of problem: Simulation of radio-wave propagation over variable terrain on the Earth?s surface, and through homogeneous and inhomogeneous atmosphere.Solution method: The program implements one-way and two-way Split-Step Parabolic Equation (SSPE) algorithm, with wide-angle propagator. The SSPE is, in general, an initial-value problem starting from a reference range (typically from an antenna), and marching out in range by obtaining the field along the vertical direction at each range step, through the use of step-by-step Fourier transformations. The two-way algorithm incorporates the backward-propagating waves into the standard one-way SSPE by utilizing an iterative forward–backward scheme for modeling multipath effects over a staircase-approximated terrain.Unusual features: This is the first software package implementing a recursive forward–backward SSPE algorithm to account for the multipath effects during radio-wave propagation, and enabling the user to easily analyze and visualize the results of the two-way propagation with GUI capabilities.Running time: Problem dependent. Typically, it is about 1.5 ms (for conducting ground) and 4 ms (for lossy ground) per range step for a vertical field profile of vector length 1500, on Intel Core 2 Duo 1.6 GHz with 2 GB RAM under Windows Vista. 相似文献5.
Ayfer Sarac Dolunay Şakar Ozlem Cankurtaran Ferdane Yılmaz Karaman 《Polymer Bulletin》2005,53(5-6):349-357
Summary The retention diagrams of benzene, toluene, ethyl benzene, chloro benzene, n-propyl benzene, isopropyl benzene, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate and isoamyl acetate on the polycaprolactone were plotted at temperatures between 70 and 140oC by inverse gas chromatography technique. Percent crystallinity of polycaprolactone were obtained at temperatures below melting point from the retention diagrams of benzene, toluene and ethyl benzene. It was concluded that the data obtained by inverse gas chromatography were comparable those of obtained by differential scanning calorimetry. Specific retention volume, Vgo, Flory-Huggins polymer-solvent interaction parameters, 12, the weight fraction activity coefficients of the solvents at infinite dilution, 1, effective exchange energy parameters, Xeff were determined. Later, the partial molar heat of sorption, H1,sorp and the partial molar heat of mixing, H1 were obtained from the slope of the logarithm of specific retention volume, Ln Vgo versus 1/T plot and from the slope of the logarithm of the weight fraction activity coefficients, 1versus 1/T plot, respectively. 相似文献
6.
A new instance-based learning method is presented for regression problems with high-dimensional data. As an instance-based approach, the conventional method, KNN, is very popular for classification. Although KNN performs well on classification tasks, it does not perform as well on regression problems. We have developed a new instance-based method, called Regression by Partitioning Feature Projections (RPFP) which is designed to meet the requirement for a lazy method that achieves high levels of accuracy on regression problems. RPFP gives better performance than well-known eager approaches found in machine learning and statistics such as MARS, rule-based regression, and regression tree induction systems. The most important property of RPFP is that it is a projection-based approach that can handle interactions. We show that it outperforms existing eager or lazy approaches on many domains when there are many missing values in the training data. 相似文献
7.
Lutfiye Altay Ebru Bozaci Metehan Atagur Kutlay Sever Gozde Sevig Tantug Mehmet Sarikanat Yoldas Seki 《应用聚合物科学杂志》2019,136(9):47131
To increase the mechanical properties of recycled carbon fiber-reinforced polypropylene (PP) composites, recycled carbon fibers (RCF) were subjected to atmospheric plasma treatment at different plasma powers (100, 200, and 300 W). The changes on surface topography and roughness of RCF were examined by atomic force microscopy. Plasma treatment of RCF increased the roughness value of RCF. The variation of surface elemental compositions and tensile strength of RCF were determined by using X-ray photoelectron spectroscopy and tensile test, respectively. Plasma-treated RCF-reinforced PP composites were fabricated using high speed thermo-kinetic mixer. Plasma treatment of RCF at 100 W increased the tensile and flexural strength values of RCF-reinforced PP composites considerably by 17 and 11%, respectively. However, plasma treatment of RCF at higher plasma powers (200 W and 300 W) decreased tensile and flexural strength values of composites because of the etching of RCF. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47131. 相似文献
8.
El Mahdi Halim Hubert Perrot Ozlem Sel Catherine Debiemme-Chouvy Khalid Lafdi Mama El Rhazi 《International Journal of Hydrogen Energy》2021,46(38):19926-19938
The development of highly efficient catalysts using inexpensive and earth-abundant metals is a crucial factor in a large-scale commercialization of direct methanol fuel cells (DMFCs). In this study, we explored a new catalyst based on copper nanodendrites (CuNDs) supported on carbon nanofibers/poly (para-phenylenediamine) (CNF/PpPD) nanocomposite for methanol oxidation reaction (MOR). The catalyst support was prepared on a carbon paste electrode by electropolymerization of para-phenylenediamine monomer on a drop-cast carbon nanofibers network. Afterwards, CuNDs were electrodeposited on the nanocomposite through a potentiostatic method. The morphology and the structure of the prepared nanomaterials were characterized by transmission electron microscope, scanning electron microscope, energy dispersive X-ray, X-ray diffraction, and X-ray photoelectron spectroscope. The results suggested that a three-dimensional nanodendritic structure consisting of Cu2O and Cu(OH)2 formed on the hybrid CNF/PpPD nanocomposite. The catalytic performance of CuNDs supported on CNF, PpPD and CNF/PpPD was evaluated for MOR under alkaline conditions. The CNF/PpPD/CuNDs exhibits a highest activity (50 mA cm?2) and stability toward MOR over 6 h, with respect to CNF/CuNDs (40 mA cm?2) and PpPD/CuNDs (36 mA cm?2). This inexpensive catalyst with high catalytic activity and stability is a promising anode catalyst for alkaline DMFC applications. 相似文献
9.
Bilge N. Altay Veronika Husovska Alexandra Pekarovicova Paul D. Fleming 《Color research and application》2019,44(6):910-916
Unused base inks that are not going to be used for printing production are considered to be hazardous materials. Their disposal is expensive, and strict environmental regulations should be followed for their disposal. As an alternative, this article describes how spectral data of unused base inks can be gathered and mixed to generate new colors to incorporate them back to print production for small‐volume jobs. In this study, 30 different Pantone colors were selected as target colors. The CIE L*a*b* spectral data of Pantone colors and unused base inks were gathered via a spectrophotometer. A commercial formulation software, based on multiflux theory and CIE L*a*b* color space, was used to formulate ink recipes that contained the base inks. To quantify the performance of ink recipes, they were mixed and printed using an offset printability tester. The CIELAB ΔE*ab metric, developed by CIE, was used to detect the visual differences between the target Pantone Color and printed colors. 相似文献
10.
Ozlem Karahan Ozgun Bertan Basak Ceren Eropak Seda Abat Gamze Kirim Emine Girgin Asude Hanedar Elcin Gunes Ercan Citil Erdem Görgün Cigdem Yangin Gomec Fatos Germirli Babuna Suleyman Ovez Aysegul Tanik Izzet Ozturk Cumali Kinaci Yakup Karaaslan Sibel Mine Gucver Esra Siltu Aybala Koc Orhon 《Clean Technologies and Environmental Policy》2017,19(1):105-122
Monitoring and control of dangerous substances discharged into receiving waters have attracted more attention lately. Since it is not possible to analyze every single substance, a prioritization methodology is needed for the selection of those to be monitored. Existing well-developed models require significant amount of data for reliable outcomes. This paper presents a methodology to prioritize the dangerous substances having adverse effects on freshwaters in Turkey, where data are scarce. Such a methodology will also serve as a solid model for other countries with limited background data. The adopted methodology enabled the elimination of chemicals to generate a candidate list composed of 608 substances among more than 5000 substances. Further screening and prioritization were conducted using different assessment methods (i.e., Total Hazard Value, Total Impact Value, Combined Monitoring-based, and Modelling-based Priority Setting) to obtain a proposed Final Candidate Specific Pollutants List of 150 dangerous substances. The proposed Candidate National Pollutant List of Turkey was established by combining 45 priority pollutants of the European Union with a list of candidate specific pollutants. According to the outcomes of this study, monitoring and controlling of 195 dangerous substances in freshwaters are recommended. Further detailed studies should be conducted in order to observe the actual levels of these dangerous substances in freshwaters followed by a review of the monitoring list accordingly. Moreover, further revisions might be required in the proposed list due to some possible versatile conditions in terms of sampling points (i.e., change in the location of industries). 相似文献