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1.
The early history of the IEEE Microwave Theory and Techniques Society (IEEE MTT-S) is summarized since its founding in 1952, and all administrative committee members and presidents are listed. Some of the more recent changes resulting from growth and multinational participation are described. Publications are discussed with editors listed for this Transactions, the IEEE Microwave and Wireless Components Letters, the IEEE Microwave Newsletter, and IEEE Microwave Magazine. The chronological evolution of the IEEE MTT-S's awards is presented, including a listing of all award winners. Distinguished lecturers and microwave symposia sites and chairpersons are also discussed. Early technology trends are described 相似文献
2.
N‐p‐Bromophenylmaleimide (BrPMI) does not polymerize in solution by conventional free radical mechanism. However, it readily polymerized in bulk when mixed with a free radical initiator and heated in a microwave oven for 7–8 min. Copolymerization of ethyl methacrylate or butyl methacrylate with BrPMI was conducted in dioxane. The copolymers were characterized by IR and 1H NMR spectroscopy and gel permeation chromatography. The monomer reactivity ratios were calculated by a non‐linear least‐square analysis. Thermal analysis indicated a great improvement in thermal stability of the copolymers compared with the methacrylate homopolymers. BrPMI was also polymerized in bulk in the DSC pan, which allowed the calculation of the activation energy of its polymerization. Copyright © 2003 Society of Chemical Industry 相似文献
3.
Anthony L. Andrady Carlos M. Nunez Bor‐Sen Chiou Saad A. Khan 《Polymer Engineering and Science》2002,42(11):2065-2071
The solution rheology of different generations of hyperbranched polyesters in N‐methyl‐2‐pyrrolidinone (NMP) solvent was examined in this study. The solutions exhibited Newtonian behavior over a wide range of polyester concentrations. Also, the relative viscosities of poly(amidoamine) (PAMAM) dendrimers in ethylenediamine were compared with those of the hyperbranched polyesters in NMP. Both types of dendritic polymers have relative viscosities that are exponential functions of their molar fraction in solution. The slopes of these relative viscosity curves show a linear relationship with respect to the generation number. PAMAM dendrimers have the greater slopes for each generation, reflecting their relatively larger intrinsic viscosity values. 相似文献
4.
Rapid determination of the membrane potential of mitochondria in small biopsy specimens of the liver
Y Yamamoto M Obara W Isselhard J Sturz T Morimoto T Minor S Saad K Ozawa 《Canadian Metallurgical Quarterly》1995,27(3):145-150
In liver transplantation, graft viability is ideally to be determined before implantation. Integrity of mitochondria may be a prerequisite to a viable graft. A new method is presented, which allows for the determination of the membrane potential of mitochondria (MPM; mV) in state 4 respiration within 50 min in 40-mg specimens, employing rhodamine 123 as a probe. Normal control showed a MPM of 239.2 mV. Storage in saline at 37 degrees C yielded an impaired MPM of 153.5 mV within 3 h. The cold storage at 1 degree C could preserve MPM at quasi-normal after 3 h but reduced it significantly after 24 h to 222.2 mV in saline (p < 0.005 vs. control) and 231.0 mV in UW solution (p < 0.05 vs. control): the difference between the 24-hour values was significant (p < 0.05). 相似文献
5.
Amr Fouda Mohamed A. Awad Ahmed M. Eid Ebrahim Saied Mohammed G. Barghoth Mohammed F. Hamza Mohamed F. Awad Salah Abdelbary Saad El-Din Hassan 《International journal of molecular sciences》2021,22(10)
The discovery of eco-friendly, rapid, and cost-effective compounds to control diseases caused by microbes and insects are the main challenges. Herein, the magnesium oxide nanoparticles (MgO-NPs) are successfully fabricated by harnessing the metabolites secreted by Penicillium chrysogenum. The fabricated MgO-NPs were characterized using UV-Vis, XRD, TEM, DLS, EDX, FT-IR, and XPS analyses. Data showed the successful formation of crystallographic, spherical, well-dispersed MgO-NPs with sizes of 7–40 nm at a maximum wavelength of 250 nm. The EDX analysis confirms the presence of Mg and O ions as the main components with weight percentages of 13.62% and 7.76%, respectively. The activity of MgO-NPs as an antimicrobial agent was investigated against pathogens Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans, and exhibited zone of inhibitions of 12.0 ± 0.0, 12.7 ± 0.9, 23.3 ± 0.8, 17.7 ± 1.6, and 14.7 ± 0.6 mm respectively, at 200 µg mL−1. The activity is decreased by decreasing the MgO-NPs concentration. The biogenic MgO-NPs exhibit high efficacy against different larvae instar and pupa of Anopheles stephensi, with LC50 values of 12.5–15.5 ppm for I–IV larvae instar and 16.5 ppm for the pupa. Additionally, 5 mg/cm2 of MgO-NPs showed the highest protection percentages against adults of Anopheles stephensi, with values of 100% for 150 min and 67.6% ± 1.4% for 210 min. 相似文献
6.
A study on the functional and nutritional properties of sesame (Sesamum indicum, L.) flour, concentrate and enzymatic hydrolysates, demonstrated that nitrogen solubility of the hydrolysates is improved, in water (85%) and at different pHs (91-95%), by the action of neutrasa 0.5L and alcalasa 0.6L, yielding a product with good emulsifying and improved foaming properties. Hydrolysates produced by the pH-stat method, then freeze-dried and spray-dried presented a PER of 1.1 and 0.9, respectively. The flour and the concentrate had PER values of 1.2. Supplementation of one of the hydrolysates with soya hydrolysate (1:1), improved the PER to a value similar to that of casein. Use of neutrasa 0.5L and alcalasa 0.6L enzymes, enhances the sesame protein solubility without modifying extensively the PER. Besides, it yields a dehydrated product with improved emulsifying and foaming properties. 相似文献
7.
The electrochemical behavior of Li/V6O13 cells is investigated at room temperature (22 °C) both in liquid electrolyte consisting of oligomeric poly(ethyleneglycol)dimethylether+lithium bis(trifluoromethylsulfonylimide) and composite electrolytes formed by blending the liquid electrolyte with silica nanoparticles (fumed silica). The addition of fumed silica yields a gel-like electrolyte that demonstrates the desirable property of suppressing lithium dendrite growth due to the rigidity and immobility of the electrolyte structure. The lithium/electrolyte interfacial resistance for composite gel electrolytes is less than that for the corresponding base-liquid electrolyte, and the charge-discharge cycle performance and electrochemical efficiency for the Li/V6O13 cell is significantly improved. The effect of fumed silica surface group on the electrochemical performance is discussed; the native hydrophilic silanol surface group appears better than fumed silica that is modified with a hydrophobic octyl surface moiety. 相似文献
8.
Electrical conductivity of concrete containing silica fume 总被引:15,自引:0,他引:15
S. A. Abo El-Enein M. F. Kotkata G. B. Hanna M. Saad M. M. Abd El Razek 《Cement and Concrete Research》1995,25(8):1615-1620
The influence of silica fume on concrete properties represents an important technical research. In general, silica fume tends to improve both mechanical characteristics and durability of concrete. Thus the electrical properties of concrete containing silica fume can be studied to clarify its physical performance during hydration. The electrical conductivity of neat cement, mortar and concrete pastes was measured during setting and hardening. The ordinary Portland cement was partially replaced by different amounts of silica fume by weight. The changes in the electrical conductivity were reported during setting and hardening after gauging with water. The results of this study showed that the electrical conductivity can be used as an indication for the setting characteristics as well as the structural changes of the hardened pastes made with and without silica fume. 相似文献
9.
Standard genetic algorithms (SGAs) are investigated to optimise discrete-time proportional-integral-derivative (PID) controller parameters, by three tuning approaches, for a multivariable glass furnace process with loop interaction. Initially, standard genetic algorithms (SGAs) are used to identify control oriented models of the plant which are subsequently used for controller optimisation. An individual tuning approach without loop interaction is considered first to categorise the genetic operators, cost functions and improve searching boundaries to attain the desired performance criteria. The second tuning approach considers controller parameters optimisation with loop interaction and individual cost functions. While, the third tuning approach utilises a modified cost function which includes the total effect of both controlled variables, glass temperature and excess oxygen. This modified cost function is shown to exhibit improved control robustness and disturbance rejection under loop interaction. 相似文献
10.
Razzaq Saad Shah Babar Iqbal Farkhund Ilyas Muhammad Maqbool Fahad Rocha Alvaro 《Neural computing & applications》2023,35(11):8017-8026
Neural Computing and Applications - A lot of different methods are being opted for improving the educational standards through monitoring of the classrooms. The developed world uses Smart... 相似文献