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排序方式: 共有335条查询结果,搜索用时 15 毫秒
81.
Mehmet Cokun Hilmi Erten Kadir Demirelli Nihat Dilsiz Misir Ahmedzade 《Polymer International》2000,49(4):367-370
3‐(1‐Cyclohexyl)azetidiniyl methacrylate (CyAMA), a new methacrylate monomer, was synthesized by reaction of the sodium salt of 1‐cyclohexylazetidin‐3‐ol with methacryloyl chloride. The monomer was polymerized at 60 °C in 1,4‐dioxane solution using 2,2′‐ azobisisobutyronitrile (AIBN) as an initiator. CyAMA and poly(CyAMA) were characterized by FTIR and 1H and 13C NMR spectroscopy. The activation energy of the initiation step of the polymerization was estimated from initial rates, and the number average molecular weight of the homopolymer was determined by gel permeation chromatography (GPC). The antibacterial and antifungal effects of the monomer and homopolymer were investigated on various bacteria and fungi. The thermal stability of poly(CyAMA) was investigated by TGA, and its glass transition temperature was determined by DSC as 93 °C. © 2000 Society of Chemical Industry 相似文献
82.
Sahena Ferdosh Md Zaidul Islam Sarker Nik Norulaini Nik Ab Rahman Md Jahurul Haque Akand Kashif Ghafoor Mohamed Bin Awang Mohd Omar Ab Kadir 《Korean Journal of Chemical Engineering》2013,30(7):1466-1472
Total oil was extracted from ground fish head of Longtail tuna (Thunnus tonggol) using supercritical carbon dioxide (SC-CO2) at 20 to 40 MPa, 45 to 65 °C and 1 to 3 ml min?1. Response surface methodology (RSM) was employed to optimize the operating conditions of the SC-CO2 technique where the highest oil yield was obtained (35.6% on dry weight basis) at 40 MPa, 65 °C, and 3 ml min?1. The solubility of the oil in SC-CO2 increased from 2.9 to 14.2 g oil/100 g of CO2 with increasing pressure and temperature. The total saturated, monounsaturated and polyunsaturated fatty acids obtained were 41.6, 24.7 and 26.8%, respectively, where the omega-3 fatty acids were found to be 22.3%. A correlation was developed determining the coefficients of the second-order polynomial equation where the extraction parameters of SC-CO2 method to extract fish oil from fish sample were successfully optimized using response surface methodology. 相似文献
83.
The incorporation of SO3? groups into a polypyrrole backbone was successfully carried out using FSO3H/acetonitrile medium. The degree of sulfonation (sulfonation or sulfur‐to‐nitrogen ratio) of polymer was controlled by varying FSO3H concentration while the film was being electrodeposited. The cyclic voltammograms of the electrodeposited films were taken between ?1.00 and +2.00 V (versus Ag/AgCl) in blank solution. A substantial effect on the electrical conductivity was observed upon the incorporation of SO3? groups in the polypyrrole polymeric chain. The elemental analysis results of the freshly prepared and reduced films give independent evidence that the SO3? groups are covalently bound to the structure. FTIR, UV‐Vis, spectroscopy and SEM techniques were used to characterize the electrosynthesized polypyrrole films. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 526–533, 2004 相似文献
84.
For the first time, the electrosynthesis of poly(pyrrole-co-bithiophene) copolymers (P(Py-co-BT) I, II, III) was carried out using the potentiostatic technique on stainless steel (SS) electrode from aqueous oxalic acid solutions containing fixed concentration of bithiophene (BT) and different concentrations of pyrrole (Py) in the presence of sodium dodecylsulfate (SDS). Corrosion protection behaviors of these copolymer-coated steels were investigated in 3.5% NaCl solution by potentiodynamic polarization, Tafel test technique and electrochemical impedance spectroscopy (EIS). Among the protective copolymer coatings, the P(Py-co-BT) II, which was obtained from polymerization solution containing 0.025 M Py, exhibited the best protection against corrosion. Hence, only this copolymer was characterized by cyclic voltammetry, FT-IR, UV–vis, conductivity measurement and differential scanning calorimetry (DSC) by comparing with those of the polybithiophene (PBT) and polypyrrole (PPy) homopolymers. It was determined that this polymer was the polypyrrole-based copolymer. The incorporation of BT units into PPy chains not only increased dry conductivity but also developed the toughness of polymer. 相似文献
85.
Poly(N-ethylaniline) (PNEA) coatings were grown by potentiodynamic synthesis technique on 304 stainless steel (SS) alloy from 0.1 M of N-ethylaniline (NEA) in 0.3 M oxalic acid solution. Characterization of adhesive and electroactive PNEA coatings was carried out by cyclic voltammetry, FT-IR spectroscopy and scanning electron microscopy (SEM) techniques. The protective properties of PNEA coatings on SS were elucidated using linear anodic potentiodynamic polarization, Tafel and electrochemical impedance spectroscopy (EIS) test techniques, in highly aggressive 0.5 M HCl and 0.5 M NaCl solutions. Linear anodic potentiodynamic polarization test results proved that PNEA coating improved the degree of protection against pitting corrosion in HCl and NaCl solutions. Tafel test results showed that PNEA coating appears to enhancement protection for SS in 0.5 M NaCl and 0.5 M HCl solutions. However, according to long-term EIS results, PNEA coating is better for the protection of SS electrodes during the long immersion period in NaCl compared to that in HCl medium. 相似文献
86.
In metal cutting, the problems need to be well analyzed in order to take precautions before any unexpected results are encountered. This process plays a significant role in achieving consistent quality and in controlling the overall cost of manufacturing. However, it is a difficult task that needs an expert who has a great deal of information and experience in metal cutting. In the present paper, a knowledge-based expert system (COROSolve) that investigates problems that are encountered in three main metal cutting areas: turning, milling and drilling is developed. A great deal of metal cutting operations such as external/internal turning with negative/positive inserts, aluminum turning, parting bars/tubes, grooving, profiling, recessing and threading operations in turning; face milling, square shoulder milling, end milling, multi-purpose milling and side and face milling operations in milling; and drilling operations that use solid drills or drills with indexable inserts in drilling are taken into consideration. COROSolve gives recommendations for the cutting data (i.e., cutting speed, depth of cut, and feed) and updates the problem, cause and remedy database, thus the number of problems that the system can handle is increased. 相似文献
87.
Kadir Bakirci 《Canadian Metallurgical Quarterly》2008,134(4):130-134
In this study, variation of the solar radiation over horizontal surfaces for clear-sky atmospheres was predicted and compared with measurements carried out in Erzurum, Turkey (latitude: 39.55, longitude: 41.16, and altitude: 1869?m). Hottel’s clear-sky model was used in calculations of solar radiation on horizontal surfaces for clear-sky atmospheres. The results show that the model calculations are reasonably consistent with the measured data. It is recommended that Hottel’s clear-sky model can be used for solar radiation calculations in Erzurum. Also, correlation equations giving monthly averages of clear-sky and global solar radiation on horizontal surfaces have been developed. In order to indicate the performance of the correlation equations, the relative percentage error, correlation coefficient, mean percentage error, mean bias error, and root-mean-square-error methods were used. 相似文献
88.
T Gibson K Hameed M Kadir S Sultana Z Fatima A Syed 《Canadian Metallurgical Quarterly》1996,35(2):146-149
We present a case of adenoid cystic carcinoma of the trachea. The tumor could not be resected due to extensive progression but it was effectively treated endoscopically with a Nd-YAG Laser followed by 70 Gy of conventional radiotherapy. Histologically-confirmed complete remission was achieved, and the patient has lived for nearly 9 years without recurrence of disease. 相似文献
89.
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