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101.
A composite consisting of carbon nanotubes (CNT) and copper nanoparticles (CuNPs) was prepared by a chemical reduction method, and its structure characterized by scanning electron microscopy, transmission electron microscopy energy dispersive spectroscopy and FT-IR spectrometry. The hybrid composite was deposited on the surface of a disposable gold electrode that was manufactured from a commercial digital versatile gold disc by a drop casting method. The electrochemical properties of the modified electrode were investigated by cyclic voltammetry and differential pulse voltammetry. The sensor showed an excellent electrocatalytic activity towards oxidation of paracetamol (PA). The calibration plot (with current typically measured at 0.41 V vs. Ag/AgCl) is linear in the 0.5 to 80 μM concentration range, and the detection limit is as low as 10 nM. The sensor was successfully applied to the determination of PA in spiked water and tablet samples where it gave recoveries ranging between 95.25 and 100.5 %. 相似文献
102.
Ghazaleh Ghani-Moghadam Somayeh Rezaei Mohammad J. Jafari Amir H. Farahbod 《等离子体物理论文集》2021,61(9):e202100042
Plasmas created by the interaction of high power optical laser with a target surface can be used as a source of soft X-ray lasers. Plasma and pump laser characteristics play significant role in achieving high gain coefficient for such plasma based on soft X-ray lasers. In the present work, the plasma active medium parameters for germanium element at a wavelength of 19.6 nm irradiated by a double-pulse pump laser have been studied using MED103 hydrodynamic code. For this purpose, first, the effects of laser intensity, pulse width and delay time of two pulses on the gain coefficient have been investigated and the optimum conditions for the maximum gain extent of Ne-like germanium soft X-ray laser are obtained. Then, in order to calculate the intensity of such high gain lasers in which Linford equation is invalid, we have adopted the general formula of amplified spontaneous emission intensity, which is valid in all range of intensities even at much higher intensities than saturation intensity. Finally, the soft X-ray laser intensities in the saturated areas for different plasma lengths have been calculated. The results show that the output of soft X-ray laser intensity with 294 cm−1 gain coefficient can reach to about several times saturated intensity by applying a 1–2 mm plasma length as the active medium. 相似文献
103.
Fabrication of a Nanostructure Based Electrochemical Sensor for Voltammetric Determination of Epinephrine,Uric Acid and Folic Acid 下载免费PDF全文
Hadi Mahmoudi Moghaddam Hadi Beitollahi Somayeh Tajik Hossein Soltani 《Electroanalysis》2015,27(11):2620-2628
A carbon paste electrode (CPE) was modified by incorporation of graphene nano sheets and a ferrocene derivative. The modified electrode showed an excellent electrocatalytic effect on the oxidation of epinephrine. In phosphate buffer solution (PBS) of pH 7.0, the oxidation current increased linearly with concentration of epinephrine in the range of 0.05–550.0 µM and a detection limit (3σ) 27.0 nM was obtained for epinephrine. Then the modified electrode was used to determine epinephrine in an excess of uric acid and folic acid by SWV. 相似文献
104.
Dr. Somayeh Ahadi Dr. Shahid I. Awan Prof. Dr. Daniel B. Werz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(28):6264-6270
A general and efficient strategy for synthesis of tri-, hexa- and heptasaccharidic substructures of the lipopolysaccharide of Providencia rustigianii O34 is described. For the heptasaccharide seven different building blocks were employed. Special features of the structures are an α-linked galactosamine and the two embedded α-fucose units, which are either branched at positions-3 and -4 or further linked at their 2-position. Convergent strategies focused on [4+3], [3+4], and [4+2+1] couplings. Whereas the [4+3] and [3+4] coupling strategies failed the [4+2+1] strategy was successful. As monosaccharidic building blocks trichloroacetimidates and phosphates were employed. Global deprotection of the fully protected structures was achieved by Birch reaction. 相似文献
105.
A mild, efficient, and selective protocol for the one-pot $N$ -alkylation of sulfonamides with alcohols using triphenylphosphine and carbon tetrachloride is described. In this method, treatment of alcohols with a mixture of triphenylphosphine, carbon tetrachloride, and potassium sulfonylamide salts in refluxing anhydrous DMF furnishes the corresponding $N$ -alkyl sulfonamides in good to excellent yields. This protocol is highly efficient for various structurally diverse alcohols and potassium sulfonylamide salts. In this paper the influence of solvents and various reagents as sources for electrophilic-halogen instead of carbon tetrachloride in combination with triphenylphosphine have been examined. This protocol demonstrates the selectivity between primary and secondary alcohols. A plausible mechanism for this protocol has been described. 相似文献
106.
Deposition of zinc(II) oxide (ZnO) nanoparticles on the surface of silk fabrics was prepared by sequential dipping steps in alternating bath of potassium hydroxide and zinc nitrate under ultrasound irradiation. This coating involves in situ generation and deposition of ZnO in a one step. The effects of ultrasound irradiation, concentration and sequential dipping steps on growth of the ZnO nanoparticles have been studied. Results show a decrease in the particles size as increasing power of ultrasound irradiation. Also, increasing of the concentration and sequential dipping steps increase particle size. The physicochemical properties of the nanoparticles were determined by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and wavelength dispersive X-ray (WDX). 相似文献
107.
Eric Emtander Fatemeh Mohammadi Somayeh Moradi 《Czechoslovak Mathematical Journal》2011,61(3):577-607
We consider Stanley-Reisner rings k[x
1, …, x
n
]/I(H) where I(H) is the edge ideal associated to some particular classes of hypergraphs. For instance, we consider hypergraphs that are natural
generalizations of graphs that are lines and cycles, and for these we compute the Betti numbers. We also generalize some known
results about chordal graphs and study a weak form of shellability. 相似文献
108.
Synthesis and photoluminescent and nonlinear optical properties of manganese doped ZnS nanoparticles
Somayeh NazerdeylamiEsmaiel Saievar-Iranizad Zahra DehghaniMehdi Molaei 《Physica B: Condensed Matter》2011,406(1):108-111
In this work we synthesized ZnS:Mn2+ nanoparticles by chemical method using PVP (polyvinylpyrrolidone) as a capping agent in aqueous solution. The structure and optical properties of the resultant product were characterized using UV-vis optical spectroscopy, X-ray diffraction (XRD), photoluminescence (PL) and z-scan techniques. UV-vis spectra for all samples showed an excitonic peak at around 292 nm, indicating that concentration of Mn2+ ions does not alter the band gap of nanoparticles. XRD patterns showed that the ZnS:Mn2+ nanoparticles have zinc blende structure with the average crystalline sizes of about 2 nm. The room temperature photoluminescence (PL) spectrum of ZnS:Mn2+ exhibited an orange-red emission at 594 nm due to the 4T1-6A1 transition in Mn2+. The PL intensity increased with increase in the Mn2+ ion concentration. The second-order nonlinear optical properties of nanoparticles were studied using a continuous-wave (CW) He-Ne laser by z-scan technique. The nonlinear refractive indices of nanoparticles were in the order of 10−8 cm2/W with negative sign and the nonlinear absorption indices of these nanoparticles were obtained to be about 10−3 cm/W with positive sign. 相似文献
109.
Bardajee GR Pourjavadi A Ghavami S Soleyman R Jafarpour F 《Journal of photochemistry and photobiology. B, Biology》2011,102(3):232-240
A highly swelling nanoporous hydrogel (NPH) was synthesized via UV-irradiation graft copolymerization of acrylic acid (AA) onto salep backbone and its application as a carrier matrix for colonic delivery of tetracycline hydrochloride (TH) was investigated. Optimized synthesis of the hydrogel was performed by the classic method. The swelling behavior of optimum hydrogel was measured in different media. The hydrogel formation was confirmed by Fourier transform infrared spectroscopy (FTIR) and thermo-gravimetric analysis (TGA/DTG/DTA). The study of the surface morphology of hydrogels using SEM showed a nanoporous (average pore size: about 350nm) structure for the sample obtained under optimized conditions. The drug delivery results demonstrated that this NPH could successfully deliver a drug to the colon without losing the drug in the stomach, and could be a good candidate as an orally administrated drug delivery system. 相似文献
110.
Sajjad Ahmadi Zinatossadat Hossaini Daryoush Zareyee Somayeh Soleimani Amiri Sattar Arshadi 《Journal of heterocyclic chemistry》2024,61(1):110-117
In this research, the synthesis of novel derivatives of spiroisatins in high yields was investigated. These new compounds were synthesized using a multicomponent reaction (MCR) of isatin, malononitrile, acetophenone derivatives, diethyl oxalate, primary amines, and Et3N in aqueous media. Under similar conditions, spiropyrroloisatins were prepared using MCRs of synthesized spiroistins. The antioxidant activity of newly synthesized spiroisatins is due to having an NH group which was evaluated by two procedures. Also, the antimicrobial activity of newly generated spiroisatins was evaluated by a disk distribution process utilizing two kinds of Gram-negative bacteria and Gram-positive bacteria and bacterial growth was stopped using these compounds. The advantages of this method are short reaction times, high yields of products, and the easy separation of catalyst and product using simple procedures. 相似文献