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1.
The interaction between poly(methymethacrylate) (PMMA) and poly(vinyl chloride) (PVC) has been studied indilute urea solutions of dimethylformamide (DMF) at 28℃ using a dilute solution viscometry method. The results show thatthe polymer mixtures are compatible in DMF solution in the absence of urea. The influence of urea addition on the degree ofcompatibility of the polymer mixtures has been studied in terms of the compatibility parameters (△b_m and △[η]_m). It wasfound that the compatibility of the polymer mixtures is decreased with increasing urea addition, passing through a minimumat 0.5 M urea. 相似文献
2.
A. M. Abushanab A. A. S. El-Khaldy R. M. Baraka M. A. Wasif 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):577-586
Diphenyl diselenide reacts with O,O-dialkyl and alkylene dithiophosphoric acids in equimolar amounts in refluxing benzene to yield Ph 2 Se 2 HS 2 P(OR) 2 , R = Et, Pr-n, Pr-i, Bu-i and Ph, and Ph 2 Se 2 HS 2 POGO where G = CH 2 CMe 2 CH 2 m , --CH 2 CEt 2 CH 2 m , and --CMe 2 CMe 2 m . The complexes are sticky solids, soluble in common organic solvents and monomeric in nature. These have been characterized on the basis of elemental analysis, molecular weight determinations, UV, IR, and NMR ( 1 H, 13 C, and 31 P NMR). Spectral data reveal addition of dithiophosphate moieties to Ph 2 Se 2 . 相似文献
3.
N. Bel Baraka 《International Journal of Theoretical Physics》2002,41(4):737-752
Comparing the star product defined by Takhtajan on the Poisson–Lie group GL(2) and any star product calculated from the Kontsevich's graphs (any K-star product) on the same group, we show, by direct computation, that the Takhtajan star product on GL(2) can't be written as a K-star product. 相似文献
4.
Mahmoud M. Sebaiy Abdullah A. El‐Shanawany Mohamed M. Baraka Lobna M. Abdel‐Aziz 《中国化学会会志》2019,66(2):179-187
This article presents a continuous capillary electrophoresis with laser‐induced fluorescence (CE‐LIF) following spectral studies of the noncovalent interactions between novel Squarylium Boronic Acid 4 (SQ‐BA4) & Squarylium Diboronic Acid 2 (SQ‐DBA2) squarylium dyes and human serum albumin (HSA). Two protocols were used wherein the on‐column‐labeling protocol was found to be more sensitive than the precolumn one by showing a better enhancement in the peak area of the HSA–dye complex besides lower limits of detection (LODs) for HSA. Also, stability studies were conducted with or without HSA using precolumn‐labeling mode over one week exhibiting the superiority of SQ‐BA4 to SQ‐DBA2. Then, a mixture containing three model proteins, HSA, β‐lactoglobulin B, and transferrin, was labeled on‐column with both dyes and completely resolved by CE‐LIF after optimization of several parameters. Both dyes provided lower LODs for HSA than those of β‐lactoglobulin B and transferrin with higher sensitivities. In addition, the SQ‐BA4 dye showed again greater sensitivities with all the three proteins than SQ‐DBA2. 相似文献
5.
M.G.A. Khedr S.M.Abd El Haleem A. Baraka 《Journal of Electroanalytical Chemistry》1985,184(1):161-169
Streaming potentials have been measured by the fast pulse method for cellulose acetate membranes cured at 85 and 95°C. Bounding, solutions of Li+, Na+, K+, Cs+, Mg2+, Sr2+, Ba2+ and La3+ chlorides were used in the concentration of 10?4-10?1M. The streaming potenial was shown to depend on the nature of the cation and to increase with decreasing solution concentration.Rather good consistency was obtained in dilute solutions between the electroosmotic cross coefficients calculated from the streaming potentials and from the electroosmosis measurements for Part I (M.G.A. Khedr, S.M. Abd el Haleem and A. Baraka, J. Electronal. Chem. 182 (1985) 157), according to the Onsager reciprocal relations. The deviation observed at higher concentrations, independent of the cation nature, is attributed to concentration polarization and/or excessive water transport encountered in electroosmosis measurements.Determination of additional phenomenological coefficients of the same system, the hydraulic permeability and the electric resistance enabled the estimation of the effective exchange capacity of modified cellulose acetate membranes. The resulting value of 2.1×10?3 mol of unit charge/1 of pore liquid is compared to the corresponding values previously reported on a different basis. 相似文献
6.
A. Alian M. Baraka H. Flex S. Hammouda 《Journal of Radioanalytical and Nuclear Chemistry》1977,36(2):375-388
The radioactive tracer technique was used for studying the extraction and predicting the best conditions of separation of
arsenic halides by organic solvents of different nature. Sulphuric acid was found to enhance the extraction of arsenic halides.
Extraction of AsI3 increases in the order cyclohexane <CCL4 toluene <o-xylene <CHCl4 and is quantitative by benzene and nitrobenzene. For a given extraction increases in the order AsCl3<AsBr3< <AsI3. Spectral measurements were made on some solvents; at maximum absorption there was a linearity between absorbance and AsI3 concentration up to 2·10−4 M for o-xylene and to 2.5·10−4 M for nitrobenzene. 相似文献
7.
Two new compounds: 2-(3',4'-dihydroxyphenyl) ethyl-3-O-α-L-rhamnopyranosyl-4-O-p-hydroxyphenylacetyl-6-O-caffeoyl-β-D-glucopyranoside and 2-(3',4'-dihydroxyphenyl) ethyl-3-O-α-L-rhamnopyranosyl-4-O-piperidine-3-carboxylic acid-6-O-caffeoyl-β-D-glucopyranoside were isolated from the stem bark of Jacaranda mimosaefolia. In addition, the known compounds lupeol, betulinaldehyde, terminic acid, betulinic acid, maslinic acid, β-sitosterol glucoside and isoacteoside were isolated and identified. 相似文献
8.
A new coordination polymer, Zn-(OC-AMAM-CO) CP, has been synthesized from Zn (II) as ionic node and 2,2′-((1,2-phenylenebis [azanediyl])bis (carbonyl))dibenzoic acid, (OC-AMAM-CO), as a new linker, where (OC-AMAM-CO) has been synthesized as an amide product through condensation reaction of phthalic acid and o-phenylenediamine. The amide product (OC-AMAM-CO) and Zn-(OC-AMAM-CO) CP were characterized via FTIR and PXRD analyses, and Zn-(OC-AMAM-CO) CP was further characterized via SEM/EDX and XPS analyses. Moreover, DFT study was performed to shed light on the both structures of (OC-AMAM-CO) and Zn-(OC-AMAM-CO). PXRD analysis revealed the successful syntheses of the new linker (OC-AMAM-CO) and Zn-(OC-AMAM-CO) CP where the new CP is crystalline. DFT study revealed that the 3D topological structure assembled through coordination, π–π stacking, and hydrogen bonding. Zn-(OC-AMAM-CO) CP was applied as an adsorbent for the removal of Cu (II) from water as it has abundant chelating groups that serve as adsorptive coordinating sites. Isotherm study revealed the obedience of Cu (II)/Zn-(OC-AMAM-CO) CP adsorption system to Langmuir modeling with adsorption capacity of about 55 mg/g. A kinetic study showed that the rate of adsorption was a pseudo-first-order type. Further, adsorption process was found to be strongly diffusion dependent. 相似文献
9.
The intermolecular interaction between poly(methyl methacrylate) (PMMA) and polystyrene (PS) intetrahydrofuran (THF) and N,N'-dimethyl formamide (DMF) solvents was studied at 28℃ using a dilute solution viscometrymethod. Solvent is believed to play a key role in characterizing the viscosity behavior of the polymer solution. The intrinsicviscosity and viscosity interaction parameter were experimentally measured for the binary (solvent/polymer) and for theternary systems in two solvents. The compatibility of the polymer mixture was discussed in terms of the sign of △b_m. Theresults show that the compatibility of PMMA/PS blend in DMF is larger than that in THF. 相似文献
10.
Nasman Omar S. M. Baraka Rajai M. Khaldi Adnan A. Nahhal Issa El Varkey Saji P. Shakir Mohammad 《Transition Metal Chemistry》1997,22(3):273-276
A new series of CoII, NiII, CuII and ZnII complexes incorporating pentaazamacrocyclic ligands has been prepared via the template condensation of o-aminobenzoic acid with succinic or phthalic acids in the presence of diethylenetriamine. The overall geometry and mode of bonding have been deduced on the basis of elemental analyses, i.r., 1H-n.m.r., e.p.r. and u.v.-vis. spectral studies, and conductivity and magnetic susceptibility measurements. An octahedral geometry is proposed for all the complexes, where five coordination sites are occupied by the macrocyclic nitrogens and the sixth by an anion. 相似文献