• Applied Chemistry for Engineering
• /
• v.8 no.3
• /
• pp.374-381
• /
• 1997

Ceramic membranes are prepared by using molding method of the glass materials, ceramic-silicone composite membranes are synthesized with immersing silicone compound of sodiumate, $S_3$-Al, S3and we investigated the properties of gas permeation. Ceramic membranes and ceramic-sodiumate membranes that has been prepared were identified as porous structure and ceramic-$S_3$-Al membranes and ceramic-$S_3$ membranes were showed with dense structure by immersion of silicone compounds. Gas permeation properties through the ceramic membranes and ceramic-sodiumate membranes decreased with increasing temperature and linearly increased with increasing pressure, ceramic-$S_3$-Al membranes and ceramic-$S_3$ membranes increased with increasing temperature and pressure effect was low. Permeation rate was found out high value with ceramic membranes and in order of ceramic-sodiumate membranes, ceramic-$S_3$-Al membranes and ceramic-$S_3$ membranes, but selectivity reversed in the order. Gas permeation mechanism through the ceramic membranes and ceramics-sodiumate composite membrane decreased with increasing temperature, suggesting an Knudsen diffusion mechanism, but ceramic-$S_3$-Al composite membranes and ceramic-$S_3$ composite membranes showed an activated diffusion by which gas permeation rates through the membranes increased with an increase in temperature.

• Journal of the Korean Ceramic Society
• /
• v.39 no.1
• /
• pp.57-67
• /
• 2002

The effect of $\beta$-TCP and PHA as additives on initial setting time, compressive strength and surface micro-structure after in vitro test of bone cement in TTCP and DCPA system was investigated. The median particle sizes of TTCP, $\beta$-TCP, DCPA and PHA for bone cement were about 3, 5, 0.9 and 4${\mu}{\textrm}{m}$, respectively. Initial setting time and compressive strength of bone cement with various composition was measured by Vicat test and Universal Testing Machine, and surface morphology and crystalline phases of bone cements were observed and analyzed by SEM and x-ray diffractometer. Initial setting time was not affected by composition but by powder/liquid ratio, and cement with PHA required double amount of solution for paste as much as one without PHA, especially. It was thought that $\beta$-TCP and PHA in bone cements was not related to setting reaction. Thus, the addition of $\beta$-TCP and PHA in bone cements decreased compressive strength and inhabited HAP from being produced on surface in vitro test. In conclusion, it was not expected that $\beta$-TCP and PHA in TTCP-DCPD bone cements enhanced the strength and bioacitivity.

• Journal of Radiation Protection and Research
• /
• v.27 no.3
• /
• pp.127-146
• /
• 2002

A method of more realistically, predicting radionuclide concentrations in crop plants varying with time after a nuclear accident was established to estimate 50 years' concentrations of $^{90}Sr$ and $^{137}Cs$ in polished rice seeds and Chinese cabbage for unit dry deposition. After non-growing season accidents, concentrations of both nuclides decreased gradually with time and $^{90}Sr$ concentrations were higher than those of $^{137}Cs$ throughout the whole period. Radionuclide concentrations in the 1 st year after growing season accidents were on the whole higher than those after non-growing season accidents by factors of up to 30 for $^{90}Sr$ and up to 1,000 for $^{137}Cs$. In polished rice seeds, the 50 years-integrated concentration was higher for $^{90}Sr$ than for $^{137}Cs$ after non-growing season accidents, whereas the opposite was true after growing season accidents. In Chinese cabbage. however, it was higher for $^{90}Sr$ than for $^{137}Cs$ after both types of the accident. Generally speaking, the dominant pathway for the integrated concentration after the growing season accident was root uptake for $^{90}Sr$ and direct plant contamination for $^{137}Cs$. The effect of resuspension was negligible. Based on the predicted results. the direct]on of planning countermeasures was suggested for various accident conditions.

• Journal of the Korean Society of Radiology
• /
• v.85 no.2
• /
• pp.363-371
• /
• 2024

Purpose Acute cholecystitis is a complication of transarterial chemoembolization (TACE) that occasionally requires surgical intervention. We aimed to analyze the incidence and risk factors of cholecystitis requiring surgical intervention in patients with embolic material uptake on cone beam CT (CBCT) performed immediately after various TACE procedures. Materials and Methods After a retrospective review of 2633 TACE procedures performed over a 6-year period, 120 patients with embolic material retention in the gallbladder wall on CBCT immediately after TACE were selected. We analyzed the incidence of and risk factors for acute cholecystitis. Results The overall incidence of acute cholecystitis requiring surgical intervention was 0.45% (12 of 2633 TACE procedures); however, it was present in 10% (12 of 120) of procedures that showed high-density embolic material retention in the gallbladder wall on CBCT performed immediately after TACE. Acute cholecystitis requiring surgical intervention occurred in eight patients (66.7%) who underwent direct cystic arterial embolization. Surgical intervention was performed 15 days (mean) after TACE. Conclusion Most unintended chemolipiodol deposits in the gallbladder wall resolved without intervention or surgery. However, superselective direct cystic arterial chemoembolization was associated with a high incidence of acute cholecystitis requiring surgery, and patients who undergo this procedure should be closely monitored.