The output from a pesticide screening model indicated that chemicals with low Henry's Law constants (KH) will tend to accumulate at the soil surface when water is evaporating, resulting in an ...increased volatilization with time. Volatilization losses and surface distributions of two pesticides with widely differing KH were measured to test the predictions of the screening model, particularly with respect to the importance of KH in controlling relative volatilization and vapor behavior. Volatilization of prometon 2,4-bis(isopropylamino)-6-methoxy-s-triazine, a Category III compound with low KH, increased with time with water evaporating and prometon accumulated at the soil surface. Volatilization of lindane (gamma isomer of 1,2,3,4,5,6-hexachloro-cyclohexane), a Category I compound with high KH, decreased with time with or without water evaporating and did not accumulate at the surface with water evaporating. The experimental data confirmed the model predictions that volatilization of chemicals with low KH is controlled by the air-boundary layer above the soil surface, whereas control of volatilization of Category I chemicals with high KH is within the soil. Accumulation and increased volatilization of compounds with low KH are controlled by boundary layer thickness and water evaporation rate as well as KH. The phenomena of organic chemicals with low KH accumulating at the soil surface following convective movement in evaporating water could greatly enhance their volatilization and increase their availability for photolysis and runoff into surface waters. Sufficient accumulation can occur that changes in adsorption coefficients with concentration must be taken into account in modeling their volatilization
The primary crystallization of the Ti40Zr25NisCu9Bc18 amorphous alloy was studied by isochronal differential scanning calorimetry （DSC）. The activation energy was determined by the ...Kissinger-Akahim-Sunose method. Trying to analyze the crystallization kinetics of the Ti40Zr25NigCu9Be18 amorphous alloy by two different methods, it was found that the crystallization kinetics did not obey the Johnson-Mehl-Avrami equation. A modified method in consideration of the impingement effect was proposed to perform kinetic analysis of the isochronal crystallization of this alloy. The kinetic parameters were then obtained by the linear fitting method based on the modified kinetic equation. The results show that the isochronal crystallization kinetics of the amorphous Ti40Zr25Ni8CugBe18 alloy is heating rate dependent, and the discrepancy between the Johnson-Mehl-Avrami method and the modified method increases with the increase of heating rate.
We continue our systematic statistical study of various components in gamma-ray burst (GRB) optical lightcurves. We decompose the early onset bump and the late re-brightening bump with empirical fits ...and analyze their statistical properties. Among the 146 GRBs that have well-sampled optical lightcurves, the onset and re-brightening bumps are observed in 38 and 26 GRBs, respectively. It is found that the typical rising and decaying slopes for both the onset and re-brightening bumps are ~1.5 and -1.15, respectively. No early onset bumps in the X-ray band are detected to be associated with the optical onset bumps, while an X-ray re-brightening bump is detected for half of the re-brightening optical bumps. The peak luminosity is anti-correlated with the peak time, L_p\propto t_{p}^{-1.81+/-0.32} and L_p\propto t_{p}^{-0.83+/-0.17} for the onset and re-brightening bumps, respectively. Both L_p and the isotropic energy release of the onset bumps are correlated with E_{\gamma, iso}, whereas no similar correlation is found for the re-brightening bumps. Taking the onset bumps as probes for the properties of the fireballs and their ambient medium, we find that the typical power-law index of the relativistic electrons is 2.5 and the medium density profile behaves as n\propto r^{-1} within the framework of the synchrotron external shock models. With the medium density profile obtained from our analysis, we also confirm the correlation between initial Lorentz factor (\Gamma_0) and E_{\gamma, iso} in our previous work. The jet component that produces the re-brightening bump seems to be on-axis and independent of the prompt emission jet component. Its typical kinetic energy budget would be about one order of magnitude larger than the prompt emission component, but with a lower \Gamma_0, typically several tens.
Mesoporous oxides TiO2 and ZrO2, synthesized by surfactant templating via a neutral C13（EO）6–Zr（OC3H7）4 assembly pathway, and ceria-modified TiO2 and ZrO2, prepared by a deposi-tion–precipitation（DP） ...method, featuring high surface areas and uniform pore size distributions were used as supports for gold catalysts. The supported gold catalysts were assessed for the cata-lytic abatement of air pollutants, i.e., CO, CH3OH, and（CH3）2O. The gold was supported on the mes-oporous oxides by a DP method. The supports and catalysts were characterized by powder X-ray diffraction, high-resolution transmission electron microscopy, N2 adsorption–desorption analysis, and temperature-programmed reduction technique. A high degree of synergistic interaction be-tween ceria and mesoporous ZrO2 and TiO2 as well as a positive modification of the structural and catalytic properties by ceria was observed. The ceria additive interacts with the mesoporous oxides and induces a strong effect on the reducibility of the supports. The catal
The durations (T90) of 315 GRBs detected with Fermi/GBM (8-1000 keV) by 2011 September are calculated using the Bayesian Block method. We compare the T90 distributions between this sample and those ...derived from previous/current GRB missions. We show that the T90 distribution of this GRB sample is bimodal, with a statistical significance level being comparable to those derived from the BeppoSAX/GRBM sample and the Swift/BAT sample, but lower than that derived from the CGRO/BATSE sample. The short-to-long GRB number ratio is also much lower than that derived from the BATSE sample, i.e., 1:6.5 vs 1:3. We measure T90 in several bands, i.e., 8-15, 15-25, 25-50, 50-100, 100-350, and 350-1000 keV, to investigate the energy-dependence effect of the bimodal T90 distribution. It is found that the bimodal feature is well observed in the 50-100 and 100-350 keV bands, but is only marginally acceptable in the 25-50 keV and 350-1000 keV bands. The hypothesis of the bimodality is confidently rejected in the 8-15 and 15-25 keV bands. The T90 distributions in these bands are roughly consistent with those observed by missions with similar energy bands. The parameter T90 as a function of energy follows \bar T90 \propto E^{-0.20\pm 0.02} for long GRBs. Considering the erratic X-ray and optical flares, the duration of a burst would be even much longer for most GRBs. Our results, together with the observed extended emission of some short GRBs, indicate that the central engine activity time scale would be much longer than T90} for both long and short GRBs and the observed bimodal T90 distribution may be due to an instrumental selection effect.
碩士
逢甲大學
纖維與複合材料學系
102
In this study, the diameter 1.0 mm of 304 stainless steel wires were processed from 1.0 mm to 0.2 mm using a cold drawing of one stage and two stages. Then the wires of diameter ...0.2 mm were annealed at various temperatures in the range of 400-500 oC. The phase transformation and fracture morphology of the cold-drawn and annealed stainless wires were studied. The crystalline phases of stainless steel wires were identified using Jade 5.0. The volume fraction of each crystalline phase of stainless steel wires were obtained using MAUD with Rietveld method. The mechanical properties of stainless steel wires were measured by tensile tests, and the fracture morphology of the wires were analyzed using FE-SEM.
The results of X-ray diffraction pattern demonstrated that the increase on the true strain (0→3.22) of the one stage cold drawing wires induces the formation of martensite (γ→α’) in the wires, and influences the increasing amount of α’phase. It proved that a part of α’phase reverses to γ-ph
AIM:To investigate the effects of bovine pituitary extract on the proliferation of keratocytes and maintaining the keratocyte phenotype/n v/tro.METHODS:Single keratocytes were isolated by enzyme ...digestion for in vitro culture.Three groups were designed according to the different culture media:a bovine pituitary extract(BPE)group,a fetal bovine serum(FBS)group and the control group.The phenotypes and proliferation of cultured cells were evaluated by morphology,immunofluorescent staining and mRNA expression of CD34,Lumican,VSX1,α-SMA and proliferating cell nuclear antigen(PCNA).in the BPE group,cells underwent serial subcultivation,and their phenotypes were identified by immunofluorescent staining.To analyze the proliferation of keratocytes in different concentrations of BPE,six different concentrations were designed to ascertain the most appropriate amount.RESULTS:In the BPE group,the cells spread out and presented dendritic morphology,and their dendrites connected to one another to form networks.On the third passage,most cells maintained their phenotype.In the FBS group,the cells exhibited a dendritic appearance in early cultured stages,but their morphology subsequently changed into a fibroblast-like shape.The number ofdendritic cells in BPE group was more than FBS and control groups.Immunofluorescent staining and realtime polymerase chain reaction(PCR)confirmed that few keratocytes underwent fibroblastic transformation in the BPE and control groups,and that proliferation was higher in the BPE group than in the control group.Although the proliferation was higher in the FBS group,many keratocytes underwent fibroblastic transformation.The analysis of cell morphology and mRNA expressions of CD34,PCNA and VSX1 in six group showed that different concentrations of BPE affected the proliferation obviously but didn’t affect the keratocyte phenotype,and the concentration of 40μg/mL was the most appropriate one.CONCLUSION:BPE can improve the proliferation of keratocytes and maintain their phenotype in vitro.Many keratocytes can be harvested rapidly and provide seeds for the construction of corneal stroma.
Using apparatus designed by ourselves, we obtained data on 11 binary azeotropic systems at normal pressure, and 20 binary and 7 ternary azeotropic systems at subatmospheric pressures. The data ...obtained for binary azeotropes, were used to predict the azeotropic data and vapor-liquid equilibria for ternary systems, and the heats of vaporization for azeotropic mixtures. In general, the results obtained gave linear plots of the logarithm of pressure versus the reciprocal of temperature and of the azeotrope composition versus temperature. A minimum boiling point azeotrope is usually formed by hydrocarbon-alcohol binary systems. The alcohol content of the azeotropic mixture increases as the pressure is raised, and decreases as the number of carbon atoms is increased (constant pressure).
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