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61.
Omid Sayar Mostafa M. Amini Hamidreza Moghadamzadeh Omid Sadeghi Stuart J. Khan 《Mikrochimica acta》2013,180(3-4):227-233
Nano-porous carbon (NPC) was synthesized by hydrothermal condensation of fructose and characterized by X-ray powder diffraction and also nitrogen adsorption analysis. It was then modified with amino groups and used as a sorbent for the removal of heavy metal ions. The formation of amino-modified NPC was confirmed by X-ray powder diffraction, infrared spectroscopy, thermogravimetric and elemental analysis. NPC was applied for removal of Pb(II), Cd(II), Ni(II) and Cu(II) ions. The effects of sample pH and the adsorption kinetics were studied, and the adsorption capacity was determined. The sorbent was applied to the removal of heavy metal ions in industrial waste water samples. Figure
A schematic diagram for sorbent synthesis 相似文献
62.
Hamidreza Alemohammad Ehsan Toyserkani Christ P. Paul 《Optics and Lasers in Engineering》2007,45(10):1010-1017
To realize the concept of smart tools, embedding of fiber optic sensors in the metallic structure of a cutting tool with combined laser solid freeform fabrication (LSFF) and moulding is presented in this paper. Metallic parts with embedded optical fiber sensors are capable of monitoring physical parameters like force and temperature. These sensors are advantageous relative to other conventional electric and electromagnetic sensors due to their light weight, immunity to external electromagnetic fields, small size, long-term durability, and long-range linearity. In the present work, the optical fibers (e.g., fiber Bragg grating sensor, single-mode fiber optics) are moulded under tensile forces within a mild steel casing filled by Sn–Pb to fabricate a protective layer around them. Afterwards, LSFF is utilized to deposit tungsten carbide reinforced in cobalt (WC–Co) on the surface of the mild steel component. The performance results, in which the sensor exposed to a light bandwidth, show that the maximum light power loss after embedding is about 21% implying that the fiber is not damaged during the embedding process. Also, the sensor output has a linear characteristic under compression loadings indicating that the debonding of the fiber from the protective layer is not probable. The produced samples are examined by scanning electron microscopy and X-ray diffraction to assess the physical properties of the tool. Microstructural images reveal no cracks and porosity around the fiber indicating a good bonding between the fiber and the surrounding media. Material characterizations of the manufactured tool are also discussed. 相似文献
63.
Gholamreza Khayatian Hamidreza Ahmadzadeh Vosta Kolaie Farough Nasiri Bahareh Atashkar Shahed Hassanpoor 《中国化学会会志》2010,57(1):118-123
A novel solid phase extraction technique for determination of total iron in environmental water samples was developed. The method is based on sorption of Fe(III) ions on octadecyl silica membrane disk modified with a new synthetic ligand dimethyl(E)‐2‐(2‐methoxyphenoxy)‐2‐butenedioate (I). Iron(III) is quantitatively retained on the disk in the pH range of 3–7 at a flow rate of 1–7 mL min−1. The Fe(III) eluted with 10 mL of 0.01 M EDTA and than was measured by flame atomic absorption spectrometry (FAAS) at 248.3 nm. The maximum capacity disk modified by 7 mg of ligand was found to be 197 ± 2 μg of iron(III). The breakthrough volume was greater than 2000 mL. The iron(III) was completely recovered (> 99%) from water with a preconcentration factor of more than 200. The limit of detection of the proposed method was 1.00 ng mL−1. The various cationic and anionic interferences had no effect on the recovery of iron(III) from the binary mixtures. The proposed method was successfully applied to determination of total iron from three different water samples. 相似文献
64.
Ghasem Soleimani Rad Hassen Aydi Poom Kumam Hamidreza Rahimi 《Rendiconti del Circolo Matematico di Palermo》2014,63(2):287-300
In this paper, we prove some common tripled fixed point and tripled coincidence point results for contractive conditions in a cone metric type space. Our results extend, unify and generalize well-known results in the literature, in particular the recent results of Aydi et al. (Fixed Point Theory Appl 2012:134, 2012). Some examples are also presented to validate our obtained results and new concepts. 相似文献
65.
Hamidreza Sanaeepur Abtin Ebadi Amooghin Abdolreza Moghadassi Ali Kargari Sadegh Moradi Davood Ghanbari 《先进技术聚合物》2012,23(8):1207-1218
Polymeric membranes were prepared by blending different grades of poly(ethylene glycol) (PEG) as the added polymer with acrylonitrile–butadiene–styrene as the backbone structure. The membranes were characterized by Fourier transform infrared, X‐ray diffractometry, dynamic mechanical thermal analysis, differential scanning calorimetry, and scanning electron microscopy. Furthermore, the gas permeation and separation properties of CO2/CH4 were studied. In addition, the effect of pressure (1–8 bar) and the effect of PEG content (0–40 wt%) on CO2 and CH4 permeability/selectivity were investigated. The results showed that, in more cases, with the introduction of PEG molecules, CO2/CH4 selectivity increases without significant changes in CH4 permeability, indicating that the incorporation of intermolecular interaction is suitable for the separation of gas pairs with no molecular size domination but the solution–diffusion. From the viewpoint of gas separation applications, the resultant data are in the commercially attractive region. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
66.
H Ramezani DN Christodoulides V Kovanis I Vitebskiy T Kottos 《Physical review letters》2012,109(3):033902
We show that complex PT-symmetric photonic lattices can lead to a new class of self-imaging Talbot effects. For this to occur, we find that the input field pattern has to respect specific periodicities dictated by the symmetries of the system. While at the spontaneous PT-symmetry breaking point the image revivals occur at Talbot lengths governed by the characteristics of the passive lattice, at the exact phase it depends on the gain and loss parameter, thus allowing one to control the imaging process. 相似文献
67.
Hakimeh Sharafi Mahya Abdoli Hamidreza Hajfarajollah Nima Samie Leila Alidoust Habib Abbasi Jamshid Fooladi Hossein Shahbani Zahiri Kambiz Akbari Noghabi 《Applied biochemistry and biotechnology》2014,173(5):1236-1249
A biosurfactant-producing thermophile was isolated from the Kahrizak landfill of Tehran and identified as a bacterium belonging to the genus Aneurinibacillus. A thermostable lipopeptide-type biosurfactant was purified from the culture medium of this bacterium and showed stability in the temperature range of 20–90 °C and pH range of 5–10. The produced biosurfactant could reduce the surface tension of water from 72 to 43 mN/m with a CMC of 1.21 mg/mL. The strain growing at a temperature of 45 °C produces a substantial amount of 5 g/L of biosurfactant in the medium supplemented with sunflower oil as the sole carbon source. Response surface methodology was employed to optimize the biosurfactant production using sunflower oil, sodium nitrate, and yeast extract as variables. The optimization resulted in 6.75 g/L biosurfactant production, i.e., 35 % improved as compared to the unoptimized condition. Thin-layer chromatography, FTIR spectroscopy, 1H-NMR spectroscopy, and biochemical composition analysis confirmed the lipopeptide structure of the biosurfactant. 相似文献
68.
Seyyed Shahabeddin Azimi Mansour Kalbasi Hamidreza Sadeghifar 《Journal of Optimization Theory and Applications》2014,162(1):191-201
To solve nonlinear equations by an optimization method, scaling is very important. Two types of poor scaling where: (a) the variables differ greatly in magnitude; (b) the merit function of system is highly sensitive to small changes in certain variables and relatively insensitive to changes in other variables. If poor scaling is ignored, the algorithm may produce solutions with poor quality. To solve (a), we can change units of variables. A numerical solution of the nonlinear equations produced by the finite volume method in the forced convective heat transfer of a nanofluid, as a case study, indicates that the poor scaling (b) is solved by using the Euclidean norm of columns of the Jacobian matrix as scaling data, while some researchers proposed diagonal elements of the Hessian matrix as scaling data. 相似文献
69.
The field of polymer therapeutics has evolved over the past decade and has resulted in the development of polymer-drug conjugates with a wide variety of architectures and chemical properties. Whereas traditional non-degradable polymeric carriers such as poly(ethylene glycol) (PEG) and N-(2-hydroxypropyl methacrylamide) (HPMA) copolymers have been translated to use in the clinic, functionalized polymer-drug conjugates are increasingly being utilized to obtain biodegradable, stimuli-sensitive, and targeted systems in an attempt to further enhance localized drug delivery and ease of elimination. In addition, the study of conjugates bearing both therapeutic and diagnostic agents has resulted in multifunctional carriers with the potential to both "see and treat" patients. In this paper, the rational design of polymer-drug conjugates will be discussed followed by a review of different classes of conjugates currently under investigation. The design and chemistry used for the synthesis of various conjugates will be presented with additional comments on their potential applications and current developmental status. 相似文献
70.
Gantumur Battogtokh Oyuntuya Gotov Nithya Subrahmanyam Young Tag Ko Hamidreza Ghandehari 《Macromolecular bioscience》2019,19(7)
Photodynamic therapy (PDT) is a promising cancer treatment approach. However, the photosensitizers (PS) used for PDT are often limited by their poor solubility and selectivity for tumors. The goal of this study is to improve water solubility and delivery of the photosensitizer 2‐[1‐hexyloxyethyl]‐2‐divinyl pyropheophorbide‐a (HPPH) to breast cancer cells. An N‐(2‐hydroxypropyl)methacrylamide (HPMA) copolymer–HPPH photosensitizer conjugate is synthesized with heat shock receptor glucose‐regulated protein 78 (GRP78), targeting to GRP78 receptors of MCF‐7 cells, which are upregulated under mild hyperthermia. It is found that the uptake of the GRP78 targeted pep‐HPMA‐HPPH copolymer conjugate in MCF‐7 cells is improved through heat induction. Under mild hyperthermia the targeted copolymers are more effective compared to free HPPH. These results show potential for the utility of mild hyperthermia and copolymer delivery vehicles to enhance the efficacy of photodynamic therapy. 相似文献