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Various self-circumferences of unit circles placed on a Minkowskian plane are expressed in terms of elliptic integrals of the first and second kinds. Landen's transformation is interpreted in this geometric context, and the self-circumferences are estimated asymptotically in the case of circles whose boundaries come very close to the origin. 相似文献
64.
Abdolraouf?Samadi-MaybodiEmail author Nasser?Goudarzi Hamidreza?Bijanzadeh 《Journal of solution chemistry》2005,34(3):283-295
Aluminum-27 NMR spectroscopy was used to characterize aqueous and methanolic alkaline solutions of tetramethylammonium (TMA) aluminosilicates. Aluminosilicate solutions have been prepared with different concentrations of silicon [0.577–1.24% (w/w)], aluminum [0.0022–0.239% (w/w)], methanol [0.0–0.70% (w/w)] and H2O [0.23–90% (w/w)]. All solutions contain the same ratio of Si/TMA = 1 and Si/Al molar ratios between 0.5 and 25.27Al NMR spectra of TMA aluminosilicate solutions are characterized by a variety of aluminosilicate species such as q1(Al1OSi), q2(Al2OSi), q3(Al3OSi) and q4(Al4OSi). Aluminum-27 NMR spectra of TMA aluminosilicate solutions indicate that considerable changes occurred by changing the Si/Al ratio. The distribution of aluminosilicate species was affected by the presence of the methanol and the method of mixing the silicate and aluminosilicate solutions. A methanolic aluminosilicate solution needs about twice the time required for an aqueous aluminosilicate solution to reach a steady state, i.e., the latter takes 36 h to reach steady state. Results with the same concentration of silicon and aluminum show that the formation and distribution of aluminosilicate species are strongly dependent on the solvent comprising the silicate and aluminate solutions. 相似文献
65.
Hamidreza Rahmati 《Proceedings of the American Mathematical Society》2008,136(2):467-474
Let be a -dimensional local ring, with maximal ideal , containing a field and let be a system of parameters for . If and the local cohomology module is finitely generated, then there exists an integer such that the modules have the same Betti numbers, for all .
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Sayed Zia Mohammadi Hadi Beitollahi Hamidreza Fadaeian 《Journal of Analytical Chemistry》2018,73(7):705-712
3-(4'-Amino-3'-hydroxy-biphenyl-4-yl)-acrylic acid, was synthesized and used to construct a modified-graphene oxide nano sheets paste electrode. The electro-oxidation of isoproterenol at the surface of the modified electrode was studied using cyclic voltammetry, chronoamperometry, and square wave voltammetry. Under the optimized conditions, the square wave voltammetric peak currents of isoproterenol increased linearly with isoproterenol concentrations in the range of 2.5 × 10–8 to 2.0 × 10–5 M and detection limit of 12 nM was obtained for isoproterenol. Finally this modified electrode was used for determination of isoproterenol in some real samples. 相似文献
68.
Alireza Doroudi Seyyed Mostafa Saadati Hossein Hassan Pour Faramarz Ahmadi Mostafa Erfani Saeed Rezaee Mohammad Javad Khodayar Hamidreza Samaee Behrouz Etesami 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(2):1185-1190
The (37MBq) 99mTc-MIBI complex samples were prepared due to ultrasound irradiation technique or boiled water bath method as a standard method. The qualitative and quantitative studies have been performed. The accumulation of 99mTc-MIBI complexes prepared by two above mentioned modalities were approximately 3 ± 0.1 % in the rats’ heart. The ultrasound irradiation technique is recommended to prepared 99mTc-MIBI complex in efficiently amount. Our approach can potentially reduce medical risk to the patient by avoiding any delay in acute therapy particularly for myocardial infarction patients. 相似文献
69.
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
70.
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