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排序方式: 共有906条查询结果,搜索用时 31 毫秒
101.
Mehran Javanbakht Faten Divsar Fatemeh Fatollahi Mohammad Reza Ganjali Marzieh Chaloosi 《Electrochimica acta》2009,54(23):5381-5386
This study introduces the design of an anodic stripping voltammetric (ASV) method for the silver ion determination at a carbon paste electrode (CPE), chemically modified with phenylthiourea-nanoporous silica gel (Tu-SBA-15-CPE). The electroanalytical pro includes two steps: preconcentration of metal ions at an electrode surface, followed by quantification of the accumulated species by differential pulse anodic stripping voltammetric methods. Factors affecting the performance of the anodic stripping were investigated, including the modifier quantity in the paste, the electrolyte concentrations, the solution pH and the accumulation potential or time. The most sensitive and reliable electrode contained 10% Tu-SBA-15 and 90% carbon paste. The accumulation potential and time were set at, −200 mV and 300 s, respectively, and the scan rate at 50 mV s−1 in the scan range of −200 to 700 mV. The resulting electrode demonstrated a linear response over range of silver ion concentration of 8.0-80 pmol/L with detection limit (S/N = 3) of 5 pmol/L. The prepared electrodes were used for the silver determination in sea and tap water samples and very good recovery results were obtained. The accuracy was assessed through recovery experiments and independent analysis by graphite furnace atomic absorption spectrometry. 相似文献
102.
Behrooz Maleki Fatemeh Barakchi Tabrizy Reza Tayebee Mehdi Baghayeri 《Polycyclic Aromatic Compounds》2019,39(2):93-98
Oxidative aromatization of 1,3,5-trisubstituted 2-pyrazolines by in-situ generation of NO+ from oxalic acid/sodium nitrite system has been described. The main advantages of this procedure are the use of an inexpensive and readily available catalyst, facile work-up, and improved yields in aqueous ethanol. 相似文献
103.
Fatemeh Hosseinzadeh Hossein Sarpoolaky 《International Journal of Applied Ceramic Technology》2019,16(4):1544-1556
Taguchi method (TM) and response surface methodology (RSM) have been employed to optimize three parameters, including the amounts of P123, the amounts of nitric acid and calcination temperature, in order to define an optimal setting for sol-gel synthesis of high surface area mesoporous alumina powder (MA). Herein, the comparison of the both statistical approaches has been examined and discussed considering the nitrogen adsorption as the response variable because this important character for mesoporous materials is exceedingly sensitive to the synthesis parameters. The BET surface area (SBET) and pore volume of MA under Taguchi optimal condition were 323.5 m2 g−1 and 0.551 cm3 g−1, respectively, by conducting confirmation test. Furthermore, the confirmation test showed high SBET of MA (363.4 m2 g−1), which was in a good agreement with calculated SBET result (431.25 m2 g−1) by a quadratic model under RSM optimal condition. Moreover, 3D response surface plots and 2D contour plots of desirability have been discussed to visualize the influence of input factors on response variable. It is also concluded that RSM shows more appropriate (12.33% higher SBET than TM) and efficient optimal condition with determining a quadratic function as the relationship between SBET and synthesis parameters. 相似文献
104.
Controlled Preparation and Characterization of Nigella Sativa Electrospun Pad for Controlled Release
Kalhori Fatemeh Arkan Elham Dabirian Farzad Abdi Gisya Moradipour Pouran 《SILICON》2019,11(2):593-601
Silicon - Nigella sativa (NS) oil is an anti-inflammatory agent in the traditional medicine. In the present study, novel electrospun mats contained NS oil/polyacrylonitrile as a sustained release... 相似文献
105.
Shima Ghaffari Maryam Yousefzadeh Fatemeh Mousazadegan 《Polymer Engineering and Science》2019,59(10):2032-2040
The development of functional nanofiber materials with high specific surface area and porosity has been a highly interesting field of research in recent years due to its versatile properties for diverse applications. The combination of nanofibers into material clothes can open up new opportunities to improve comfort performance and thermal management properties. In this work, we demonstrated that the porous lightweight nanofibrous membrane could be coated on the fabric and laminated to improve its thermal comfort. The polyacrylonitrile was electrospun onto the surface of the polyester fabric with three different fineness and laminated with a warp knitted interlining in a controlled condition by sewing/fusing. The effect of the nanofibers diameter, sewing and fusing process on thermal insulation, air permeability, breathability, and water resistance of the obtained three‐layer samples were studied. The results showed that the presence of the nanofibers thin layer could improve the thermal comfort by controlling the studied parameters compared to the external face fabric as control. It was obtained that the fusing technique is more efficient than sewing for this purpose. The fused samples are waterproof and windproof, while instantly venting moisture and had good thermal insulation to protect the body from cold. POLYM. ENG. SCI., 59:2032–2040, 2019. © 2019 Society of Plastics Engineers 相似文献
106.
This paper describes the microwave characterization and wettability of a uniform and light magnetic nanofibers web. Iron oxide nanoparticles/recycled poly (ethylene terephthalate) nanofibers web (Fe3O4 NPs/RPET NFs web) were fabricated from bath-sonication solution via electrospinning method. For environmental conservation and economic reasons, RPET instead of virgin material was used. After synthesizing magnetic Fe3O4 NPs with an average diameter of 35?nm by precipitation method using iron sulfate and sodium hydroxide, Fe3O4 NPs/RPET NFs web was made. The main objective of this work is to show how Fe3O4 NPs are able to significantly modify electromagnetic properties at X-band frequencies. Microwave characterization is based on the microwave scattering parameters measured in the X-band (8–12?GHz). Various characterization methods, including field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM), have been used to study morphologies, crystalline structure, magnetic, and wettability properties of NFs web. The saturation magnetization of the Fe3O4 NPs/RPET NFs web at a concentration of 5% was 2.79?emu/g. The mathematical model was estimated for magnetization, diameter and concentration by MathWorks Model Predictive Control Toolbax Software. The wettability, reflection coefficient, absorption coefficient, and EMI shielding of Fe3O4 NPs/RPET NFs web have been improved compared to RPET NFs web. 相似文献
107.
Elahe Sharifisamani Fatemeh Mousazadegan Roohollah Bagherzadeh Masoud Latifi 《Polymer Engineering and Science》2020,60(7):1520-1529
This work presents an interesting method using an electrospinning process to fabricate suture yarns loaded with curcumin to achieve reasonable mechanical properties as well as tunable drug release behavior. Different structures including different yarn counts and twists as well as core-sheath structures were used to adjust drug release properties along with improving the yarn's mechanical properties. The core parts were made of polycaprolactone and the sheath parts were made of polyethylene glycol, polylactic acid, and polycaprolactone. Drugs can be incorporated in both parts based on the required condition and application. Electrospun yarns were compared using both structural properties and their drug release profiles as metrics. The results of comparing drug release profiles of six electrospun yarns with different yarn counts and twists showed that yarns with finer fiber diameters in the core part have more drug release as well as more initial release. Overall evaluations showed that core-sheath drugloaded yarn with appropriate physical and mechanical properties can be a useful material as a drug delivery system to the site of damaged tissue. It can also be concluded that the amount and duration of drug release can be controlled using the structural parameters of electrospun yarns as an engineering tool for designing suture yarns with required properties. 相似文献
108.
Rezvan Tavakoli Saeid Vakilian Fatemeh Jamshidi-Adegani Samaneh Sharif Abdolreza Ardeshirylajimi 《国际聚合物材料杂志》2018,67(15):873-878
In situ prolonged delivery of drugs at the site of tumor can be satisfactorily accelerated patient recovery. We compared the effect of temozolomide while incorporated by polycaprolactone nanofibers on the apoptotic behavior of U87 glioma cells. After biocompatibility evaluation of nanofibers by scanning electron microscope and 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide analysis, the apoptosis of U87 cells was evaluated using p53, Bcl2 and Bax genes expression. It was found that nanofiber-temozolomide group showed a greater ability to induce apoptosis as well as have a significantly diminished initial burst release of drug compared with other groups and have promising potential in treating cancer. 相似文献
109.
Different top layer fabrication methods (amine-first, acid-first, spin coating), organic phase solvents (hexane, heptane, mixed hexane/heptane), acid acceptors (triethylamine, sodium carbonate, sodium hydroxide), and surfactant sodium dodecyl sulfate concentrations (0, 0.05, and 0.1 wt%) were utilized to fabricate thin film composite polyamide membranes for CO2/N2 separation. The results, according to an L9 orthogonal array of Taguchi approach, showed that employing acid-first method increases both CO2 permeance and CO2/N2 selectivity of the membranes at a feed gas pressure of 3 bars. On the other hand, sodium hydroxide, and triethylamine should be used, as acid acceptors, to maximize CO2 permeance and CO2/N2 selectivity, respectively. Moreover, the use of hexane solvent and 0 wt% surfactant led to maximum permeance, while, hexane solvent and 0.1 wt% surfactant were needed to reach the highest selectivity. The above level setting of synthesis parameters also resulted in the minimum sensitivity of the fabrication process to the noise factors effects. As shown by the analysis of variance, acid acceptor, and organic solvent types were the most influential parameters on CO2 permeance and CO2/N2 selectivity, respectively. The effects of fabrication method and surfactant concentration, as single factors, on permeation/selectivity responses were also investigated. 相似文献
110.