Fourier transform Raman spectra of methyl red adsorbed on untreated and pretreated ${\gamma}$-alumina and silicaalumina calcined at 900 $^{\circ}C$ under 1 atm steam flowing were recorded. Spectral analysis shows that the active species adsorbed on ${\gamma}$-alumina was to be deprotonated methyl red, and on silica-alumina to be di-protonated. This indicates that ${\gamma}$-alumina adapted in this work holds Bronsted basicity, and silica-alumina Bronsted acidity. Raman intensities of methyl red on pretreated ${\gamma}$-alumina are about three times stronger than on untreated ${\gamma}$-alumina, while spectral features are unchanged. For silica-alumina, spectral features show modified vibrational characteristics upon surface hydroxylations generated from pretreatment. Consequently, the acidity loss for silica-alumina and the basicity gain for ${\gamma}$-alumina were observed by increasing the surface hydroxyl groups on the catalysts through pretreatment of the steam calcination.
This study attempts to investigate the factors that could affect the acceptance of agricultural technologies by considering empirical factors for new agricultural technologies, based on previous studies on the acceptance of new technologies and innovations. In order to test the hypotheses, this study used a sample of 157 young farmers under the age of 39 who grow strawberries nationwide. The results are as follows. First, as a result of verifying the hypothesis on the effect of young farmers’ personal characteristics (innovation, technical competency, self-efficacy) on perceived ease of use and perceived usefulness, the hypothesis for the innovation was adopted because it directly affected perceived usefulness. And, the hypothesis for the self-efficacy was adopted because it directly affected perceived young farmers’ environmental characteristics (network, social influence) on perceived ease of use and perceived usefulness, the hypothesis for the network was rejected because no significance was secured in both perceived ease of use and perceived usefulness. On the other hand, the hypothesis for social influence was adopted because it directly affected perceived ease of use. Third, As a result of verifying the hypothesis on the relationship among the perceived ease of use, perceived usefulness, attitude toward using, and intention to accept technology, the hypothesis was adopted as it was shown that perceived ease of use had a direct effect on perceived usefulness, perceived usefulness had a direct effect on attitude toward using, and intention to accept technology, and perceived ease of use and attitude toward using, had a direct effect on the intention to accept technology. Summarizing this study, it was analyzed that innovation and selfefficacy among the personal characteristics of young farmers, and social influence among the environmental characteristics of young farmers influenced the acceptance intention of innovative technology. Based on these research results, policy implications for fostering young farmers as the subject of agricultural innovation were presented.
Separation factor for and has been determined using ion exchange resin having 1,7,13-trioxa-4,10,16-triazacyclooctadecane () as an anchor group. The ion exchange capacity of the ion exchanger was 2.0 meq/g dry resin. The lighter isotope, , is concentrated in the fluid phase, while the heavier isotope, , is enriched in the resin phase. By column chromatography [0.3 cm(I.D)30 cm (height)] using 3.0 M ammonium chloride solution as an eluent, single separation factor, , 1.018, i.e. was obtained by the Glueckauf theory from the elution curve and isotope ratios.
Background : Recently, inorganic arsenic trioxide () was reported to induce complete remiss ion in a high proportion of patients with refractory acute promyelocytic leukemia (APL). To illustrate cellular and molecular mechanisms of in the treatment of APL, many experimental studies were performed on APL- derived cell lines in vitro. Previous studies showed that inhibited proliferation and induced apoptosis in the APL- derived cell lines. This study was done to clarify the in vitro mechanisms of - induced apoptosis in APL- derived NB4 cell lines. Methods : To determine the effects of in the various concentrations, NB4 cells were cultured with 0.1 to 2 M/L of . To assay the apoptosis in NB4 cell lines, DNA fragmentation assay and TUNEL were performed. To find out the molecular change of - induced apoptotic NB4 cell lines, RT-PCR and Western blot analysis for PML- RAR chimeric protein expression and flow cytometry for bcl- 2/bax expression were performed. To clarify the caspase activation pathway, Western blot analysis and flow cytometry for procaspase express ion were performed. Results : induces apoptosis on NB4 cells in relatively high concentration (0.5 to 2 M/ L) for 2 days. After 2 days of culture the PML-RAR chimeric protein expression decreased rapidly by Western blot and RT-PCR analysis and bcl-2 expression also decreased by flow cytometry. The express ion of bax by flow cytometry showed a marked increase in high concentration (2M/ L) but there was no change in low concentration (0.5M/ L). In the Western blot analysis, the amount of pro-`enzyme of caspase-3 was significantly decreased in the cells with high concentration (2M/ L) compared with that in the cells with low concentration (0.5M/L). induces proteolytic processing of pro-caspase 7 but not pro-caspase 9 and 8. Conclusion : Apoptosis of APL- derived NB4 cell lines was induced by and progressed rapidly in higher concentrations. During apoptosis, activation of caspase- 7 pathway and degradation of PML-RAR chimeric protein, decrease in bcl- 2 and increase in bax were shown. (Korean J Hematol 2002;37: 200 2 11)
Separation of magnesium isotopes was investigated by chemical ion exchange with synthesized 1-aza-15-crown-5 bonded Merrifield peptide resin using elution chromatography. The capacity of novel monoazacrown ion exchanger was 2.3 meq g−1 dry resin. The heavier isotopes of magnesium are concentrated in the resin phase, while the lighter isotopes are enriched in the solution phase. The glass ion-exchange column used in our experiment was 35-cm long with an inner diameter of 0.2 cm, and 2.0 M NH4Cl solution was used as an eluent. The single-stage separation factor was determined according to the method of Glueckauf from the elution curve and isotopic assays. The separation factors of 24Mg2+–25Mg2+, 24Mg2+–26Mg2+, and 25Mg2+–26Mg2+ were 1.014, 1.026, and 1.012, respectively.
Experiments were conducted to determine the structural dynamic characteristics of bump foil bearing. The housing of the bearing on the journal was driven by two shakers which were used to simulate dynamic forces acting on the bump foil strips. Three different bump foils(Cu-coated bump, silicon bump, viscoelastic bump) are tested and the dynamic coefficients of three bump foils compared, based on the experimental measurements for a wide range of operating conditions. From the test results, the high damping coefficients of viscoelastic bump are achieved and the possibility of the super-bending-critical operation is suggested.
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