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排序方式: 共有1641条查询结果,搜索用时 15 毫秒
41.
Şerife Saçmacı Şenol Kartal Mustafa Saçmacı 《International journal of environmental analytical chemistry》2013,93(14):1626-1637
A simple back-extraction method was developed for the separation and preconcentration of trace levels of zinc from different matrices. Ethyl-2-(4-methoxybenzoyl)-3-(4-methoxyphenyl)-3-oxopropanoylcarbamate (EMPC) was used as a new complexing agent for the extraction of zinc(II) from the aqueous sample phase to the methyl isobutyl ketone (MIBK) phase as Zn(EMPC)2 complexes. The Zn(II) can be selectively stripped with 1?mL of 0.5?mol?L?1 HCl from Mn+(EMPC)n complexes [Ag(I), Al(III), Cd(II), Cr(III), Cu(II), Fe(II), Fe(III), Mn(II), Ni(II), Pb(II) and Pd(II)] which dissolved in MIBK phase. Some experimental parameters, which are important for the whole extraction process, including pH, sample volume, shaking time, amount of the EMPC reagent, amount of MIBK, ionic strength, and type of back-extractant were investigated. The recovery for Zn(II) was greater than 95%. The detection limit of the method was found to be 0.2?µg?L ? 1 and the relative standard deviation as 6.4%. The concentrations of Zn(II) in the certified reference materials (LGC6019 river water and NIST-1547 peach leaves) by the presented method were in good agreement with the certified values. The proposed method was succesfully applied to the determination of zinc in some natural waters, rice, hair, soil, and tea samples. 相似文献
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43.
Three magnetically recoverable Brønsted acidic calix[n]arene derivatives were successfully constructed by immobilizing calix[n]arene sulfonic acids onto silica-coated magnetic nanoparticles, a process, which allows calix[n]arene derivatives to acquire magnetic properties. All of the magnetically recoverable Brønsted acidic calix[n]arenes efficiently catalyze the coupling of electron-rich arenes with some alcohols in water. After separation and recovery from the reaction mixture by a simple magnet, these Brønsted acidic calix[n]arenes can be recycled many times without losing their catalytic activity. 相似文献
44.
Adil Mustafa Elisa Pedone Lucia Marucci Despina Moschou Mirella Di Lorenzo 《Electrophoresis》2022,43(3):501-508
Effective methods for rapid sorting of cells according to their viability are critical in T cells based therapies to prevent any risk to patients. In this context, we present a novel microfluidic device that continuously separates viable and non-viable T-cells according to their dielectric properties. A dielectrophoresis (DEP) force is generated by an array of castellated microelectrodes embedded into a microfluidic channel with a single inlet and two outlets; cells subjected to positive DEP forces are drawn toward the electrodes array and leave from the top outlet, those subjected to negative DEP forces are repelled away from the electrodes and leave from the bottom outlet. Computational fluid dynamics is used to predict the device separation efficacy, according to the applied alternative current (AC) frequency, at which the cells move from/to a negative/positive DEP region and the ionic strength of the suspension medium. The model is used to support the design of the operational conditions, confirming a separation efficiency, in terms of purity, of 96% under an applied AC frequency of 1.5 × 106 Hz and a flow rate of 20 μl/h. This work represents the first example of effective continuous sorting of viable and non-viable human T-cells in a single-inlet microfluidic chip, paving the way for lab-on-a-chip applications at the point of need. 相似文献
45.
Natali Rianika Mustafa Vincent Simon Spelbos Geert-Jan Witkamp Robert Verpoorte Young Hae Choi 《Molecules (Basel, Switzerland)》2021,26(9)
Some medicines are poorly soluble in water. For tube feeding and parenteral administration, liquid formulations are required. The discovery of natural deep eutectic solvents (NADES) opened the way to potential applications for liquid drug formulations. NADES consists of a mixture of two or more simple natural products such as sugars, amino acids, organic acids, choline/betaine, and poly-alcohols in certain molar ratios. A series of NADES with a water content of 0–30% (w/w) was screened for the ability to solubilize (in a stable way) some poorly water-soluble pharmaceuticals at a concentration of 5 mg/mL. The results showed that NADES selectively dissolved the tested drugs. Some mixtures of choline-based NADES, acid-neutral or sugars-based NADES could dissolve chloral hydrate (dissociated in water), ranitidine·HCl (polymorphism), and methylphenidate (water insoluble), at a concentration of up to 250 mg/mL, the highest concentration tested. Whereas a mixture of lactic-acid–propyleneglycol could dissolve spironolacton and trimethoprim at a concentration up to 50 and 100 mg/mL, respectively. The results showed that NADES are promising solvents for formulation of poorly water-soluble medicines for the development of parenteral and tube feeding administration of non-water-soluble medicines. The chemical stability and bioavailability of these drug in NADES needs further studies. 相似文献
46.
Mustafa Siti Fatimah Zaharah Arsad Siti Rosilah Mohamad Habsah Abdallah Hassan H. Maarof Hasmerya 《Structural chemistry》2021,32(3):1151-1161
Structural Chemistry - Binding affinity and intermolecular interactions are essential characteristics that could be used to comprehend molecular recognition between molecules in supramolecular... 相似文献
47.
In this study, facile preparation of pure and nano-sized cobalt oxides particles was achieved using low-cost mechanical ball-milling synthesis route. Microstructural and morphological properties of synthesised products were characterised by X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. XRD results indicated that the fabricated samples composed of cubic pure phase CoO and Co3O4 nanocrystalline particles with an average crystallite size of 37.2 and 31.8 nm, respectively. TEM images showed that the resulting samples consisted of agglomerates of particles with average diameter of about 37.6 nm for CoO and 31.9 nm for Co3O4. Phase purity of the prepared samples was further investigated due to their promising technological applications. Local atomic structure properties of the prepared nanoparticles were probed using synchrotron radiation-based X-ray absorption spectroscopy (XAS) including X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). EXAFS data analysis further confirmed the formation of single-phase CoO and Co3O4 nanoparticles. In addition, structural properties of cobalt oxide nanoparticles were investigated by performing density functional theory calculations at B3LYP/TZVP level and Born–Oppenheimer molecular dynamics. Theoretical calculations for both prepared samples were found to be consistent with the experimental results derived from EXAFS analysis. Obtained results herein reveals that highly crystalline and pure phase CoO and Co3O4 nanoparticles can be synthesised using simple, inexpensive and eco-friendly ball-milling method for renewable energy applications involving fuel cells and water splitting devices. 相似文献
48.
Multi‐crystalline silicon solar cells with metal‐assisted nano‐texturing using HNO3 as hole injection agent 下载免费PDF全文
In this study, metal‐assisted etching (MAE) with nitric acid (HNO3) as a hole injecting agent has been employed to texture multi‐crystalline silicon wafers. It was previously proven that addition of HNO3 enabled control of surface texturing so as to form nano‐cone shaped structures rather than nanowires. The process parameters optimized for optically efficient texturing have been applied to multi‐crystalline wafers. Fabrication of p‐type Al:BSF cells have been carried out on textured samples with thermal SiO2/PECVD‐SiNx stack passivation and screen printed metallization. Firing process has been optimized in order to obtain the best contact formation. Finally, jsc enhancement of 0.9 mA/cm2 and 0.6% absolute increase in the efficiency have been achieved. This proves that the optimized MAE texture process can be successfully used in multi‐crystalline wafer texturing with standard passivation methods.
49.
Mustafa Aghazadeh Mehdi Ghaemi Behrouz Sabour Somayeh Dalvand 《Journal of Solid State Electrochemistry》2014,18(6):1569-1584
Well-dispersed nanoparticles of nickel hydroxide were prepared via a simple electrochemical method. Electrodeposition experiments were performed from 0.005 M Ni(NO3)2 bath at a constant current density of 0.1 mA cm?2 on the steel cathode for 1 h. Recording the potential values during the deposition process revealed that the reduction of water has major role in the base electrogeneration at the applied conditions. The obtained deposit was characterized by the X-ray diffraction (XRD), infrared (IR), differential scanning calorimeter–thermogravimetric analysis, carbon–nitrogen–hydrogen (CHN), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. The CHN, XRD, and IR analyses showed that the obtained deposit has α phase of Ni(OH)2 with intercalated nitrate ions in its structure. Morphological characterization by SEM and TEM revealed that the prepared α-Ni(OH)2 is composed of well-dispersed ultrafine particles with the size of about 5 nm. The supercapacitive performance of the prepared nanoparticles was analyzed by means of cyclic voltammetry and galvanostatic charge–discharge tests. The electrochemical measurements showed an excellent supercapacitive behavior of the prepared α-Ni(OH)2 nanoparticles. It was also observed that the α-Ni(OH)2 ultrafine particles have better electrochemical characteristic and supercapacitive behavior than β-Ni(OH)2 ultrafine nanoparticles, including less positive charging potential, lower E a???E c value, better reversibility, higher E OER???E a, higher utilization of active material, higher proton diffusion coefficient, greater discharge capacity, and better cyclability. These results make the α-Ni(OH)2 nanoparticles as an excellent candidate for the supercapacitor materials. 相似文献
50.
Khoja Asif Hussain Anwar Mustafa Shakir Sehar Mehran Muhammad Taqi Mazhar Arslan Javed Adeel Amin Nor Aishah Saidina 《Research on Chemical Intermediates》2020,46(8):3817-3833
Research on Chemical Intermediates - The excess emission of greenhouse gases (GHGs) such as CO2 and CH4 is posing an acute threat to the environment, and efficient ways are being sought to utilize... 相似文献