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排序方式: 共有680条查询结果,搜索用时 31 毫秒
641.
Food irradiation is a process which exposing food to ionizing radiations and it can improve the safety of food. The pomegranate juice contained considerable anthocyanins and has become a new functional food available for dieting and health. In the present study, the effects of gamma irradiation (0–10 kGy) on the stability of anthocyanins and inhibition of microbial growth in pomegranate juice during storage were investigated. Results indicated that the irradiation at all applied doses, significantly reduced total and individual anthocyanins. Moreover, irradiation with higher dosages (3.5–10 kGy) had undesirable effect on the total content of anthocyanins. However, irradiation at 2.0 kGy had effectively diminished the total bacteria and fungi count and retarding microbial growth during storage. Based on adverse effect of gamma irradiation on ACs content of studied juices, it is not recommended to irradiate pomegranate juice with dosage higher than 2.0 kGy. 相似文献
642.
M. Afzaal D. Crouch P. O'Brien Jin-Ho Park 《Journal of Materials Science: Materials in Electronics》2003,14(9):555-557
Dithioimidobisdiisopropylphosphinato indium chloride In[(SPiPr2)2N]2Cl has been shown to be an effective single-source precursor for the deposition of indium sulfide films by aerosol-assisted chemical vapor deposition (AACVD). X-ray powder diffraction (XRPD) studies indicated that polycrystalline -In2S3 films with the tetragonal phase have been deposited on glass substrates (425–475 °C). The morphology of films was confirmed by scanning electron microscopy (SEM). Energy dispersive X-ray analysis (EDAX) indicates the presence of indium and sulfur. 相似文献
643.
L. Torkzadeh M. M. Zahedi M. Abbasi 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2007,11(10):985-990
In this note by considering the notion of (weak) dual hyper K-ideal, we obtain some related results. After that we determine the relationships between (weak) dual hyper K-ideals and (weak) hyper K-ideals. Finally, we give a characterization of hyper K-algebras of order 3 or 4 based on the (weak) dual hyper K-ideals. 相似文献
644.
J. Basiri Parsa Z. Merati M. Abbasi 《Journal of Industrial and Engineering Chemistry》2013,19(4):1350-1355
The decolorization and degradation of an organic dye, Reactive Orange 7 (RO7) in aqueous media by electrochemical oxidation process using Ti/Sb–SnO2 electrode as anode was modeled and optimized using response surface methodology (RSM) based on central composite design (CCD). The anode electrode was prepared using dip-coating and thermal decomposition method. Accordingly reduced quadratic model was developed to give the substrate color removal efficiency percentage as function of effective parameters such as: initial dye concentration, pH of the solution, electrolyte concentration and current density. The fit of the model is checked by the determination coefficient (R2). In this case, the value of the determination coefficient (R2 = 0.9949) is indicated. Maximum color removal efficiency was achieved at the obtained conditions of: pH = 4, concentration of electrolyte = 3.5 g/L and current density = 19 mA/cm2. Dye removal rate increased by increasing the concentration of electrolyte, lowering pH and increasing the current density. In optimum conditions, decolorization was obtained completely after 5 min; and the removal of chemical oxygen demand (COD) was reduced to 70.3% after 90 min. 相似文献
645.
In this article, one-dimensional transient moisture and solute diffusions in the spherical geometry during osmotic dehydration were modeled by exact analytical method and two approximate models. Approximate models have been developed based on a parabolic and power-law profile approximation for moisture and solute concentrations in the spatial direction. The proposed models were validated by experimental water loss and solid gain data obtained from osmotic dehydration of spherical cherry tomatoes in NaCl salt solution. Experiments were conducted at six combinations of two temperatures (30°C and 40°C) and three solution concentrations (10%, 18%, and 25% w/w). A two-parameter model was used to predict moisture loss and solute gain at equilibrium condition, and moisture and solute diffusivities were estimated by fitting the experimental moisture loss and solute gain data to the Fick's second law of diffusion. The values of mean relative errors for exact analytical, parabolic, and power-law approximation methods respect to the experimental data were estimated between 6.58% and 9.20%, 13.28% and 16.57%, and 5.39% and 7.60%, respectively. Although the parabolic approximation leads to simpler relations, the power-law approximation method results in higher accuracy of average concentrations over the whole domain of dehydration time. 相似文献
646.
Mohammad Reza Bafandeh Mohammad Hasan Abbasi Ali Saidi Jae-Shin Lee 《Materials Science and Engineering: B》2013,178(4):277-281
In this study, (100 ? x) K0.48Na0.48Li0.04Nb0.96Ta0.04O3 ? xSrTiO3 (0 ≤ x ≤ 10) ceramics were fabricated via normal sintering of synthesized powder by using solid state reaction. All ceramics revealed pure perovskite structure, indicating formation of solid solution between KNNLT and ST up to 10%. With increasing x, the crystal structure of ceramics changed from orthorhombic to tetragonal and finally pseudocubic symmetry when x = 10. Ceramic containing 1% ST had orthorhombic and tetragonal symmetries, simultaneously. Investigation of the variation of dielectric constant of ceramics versus temperature revealed that for ceramic with x = 1, polymorphic phase transition (PPT) temperature between orthorhombic and tetragonal is less than room temperature. Thus coexistence of two different structures in this ceramic is due to vicinity of its composition to morphotropic phase boundary (MPB). As a result, the maximum piezoelectric constant was measured for this ceramic. Ceramics containing 5 and 7.5% ST tend to appear relaxor ferroelectric behavior which is because of chemical inhomogeneities in both A- and B-sites of the ABO3 perovskite structure. 相似文献
647.
In this paper, the feasibility of 13N radioisotope production by a small plasma focus device for using in positron emission tomography (PET) has been studied. A large quantity of experimental data on the deuteron beam emission in dense plasma focuses are summarized and has been used in estimation of deuteron energy spectrum, intensity and angular distribution. The induced activity of 13N by 12C(d,n)13N reaction in an external solid target is calculated for different ‘m’ values (the power in energy distribution function of deuterons), and for a repetition rate plasma focus. A small plasma focus can produce 13N radionuclides in the order of 10 kBq in one shot, and it can be increased to few 10 MBq in a rep rate working mode with f = 10 Hz after 600 s operating time. Whereas a typical PET scan in myocardial blood perfusion assessment requires about 4 GBq radiopharmaceutical of 13N, it is concluded that a small plasma focus device, even with repetition frequency of f = 10 Hz can’t produce adequate 13N activity for this special PET imaging. Nonetheless, higher producible activities in higher energy PF devices and by endogenous production methods (i.e., nuclear reactions are induced inside the pinch itself) maybe result to introduction of an optimized repetitive high energy plasma focus as an alternative for cyclotrons in this special application. 相似文献
648.
Dust explosions-cases, causes, consequences, and control 总被引:3,自引:0,他引:3
Dust explosions pose the most serious and widespread of explosion hazards in the process industry alongside vapour cloud explosions (VCE) and boiling liquid expanding vapour explosions (BLEVE). Dust explosions almost always lead to serious financial losses in terms of damage to facilities and down time. They also often cause serious injuries to personnel, and fatalities. We present the gist of the dust explosion state-of-the-art. Illustrative case studies and past accident analyses reflect the high frequency, geographic spread, and damage potential of dust explosions across the world. The sources and triggers of dust explosions, and the measures with which different factors associated with dust explosions can be quantified are reviewed alongside dust explosion mechanism. The rest of the review is focused on the ways available to prevent dust explosion, and on cushioning the impact of a dust explosion by venting when the accident does take place. 相似文献
649.
Reducing the forming load,deletion of springback,increasing the formability of sheets as well as producing high strength parts are the main reasons to apply hot stamping process.Hot stamping process and 22MnB5 steels are the state of the art process and grades,respectively;however novel processes and steel grades are under considerations.In the current research,behavior of the steel grade MSW1200 blanks under semi and fully hot stamping processes was characterized.During semi-hot stamping process,the blank was firstly heated to a temperature of about 650℃ and then formed and quenched in the die assembly,simultaneously.Microstructure and mechanical properties of semi and fully hot stamped blanks were studied and the results were compared with those of normally water/air quenched blanks.The hot stamped blanks attained the strength values as high as water quenched blanks.The highest ductility and consequently,the best formability were achieved for the blank which had been semi-hot stamped.It was concluded that for the mentioned steel,semi-hot stamping process could be considered as an improved thermo-mechanical process which not only guaranteed a high formability,but also led to ultra high strength values. 相似文献
650.
Nikoo Darestani Farahani Fereydoon Abbasi Davani Zahra Shahbazi Rad 《Journal of Fusion Energy》2011,30(6):466-472
In this paper, best condition of filling gas pressure and operating voltage for SBUPF1 plasma focus device to have maximum
intensity of hard and soft X-ray emission has been reported. For time resolved X-ray detection, PIN detector and fast plastic
Scintillator detector with appropriate filters have been used and for time integrated X-ray emission measurement, radiography
films with appropriate filter masks have been used. Rogowski coil has been used for pinch detection. The highest hard X-ray
emission has been observed at the pressure of 0.45 mbar of Argon and discharge voltage about 23.5 kV. The highest Soft X-ray
emission has been observed at the pressure of 0.35 mbar of Argon and discharge voltage about 23.5 kV. For enhancement of hard
X-ray emission intensity, lead disk was placed in copper anode tip and measurements were repeated. Results have shown that
hard X-ray emission has been enhanced about 23% and soft X-ray emission has been enhanced about 33% with inserting a high
atomic number metal disk like lead. Results from integral X-ray measurement have shown presence of dominant peaks in ranges
13.2–15, 21–21.9 and 23.4–24.3 keV with significant spectral components in the range of 0–50 keV. Pinch size has measured
with pin hole camera and it is about 0.6 mm × 2.12 mm. Captured images with SBUPF1 have confirmed that it is a suitable source
for introspective imaging with capability of showing very fine details. 相似文献