• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.511-515
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• 2012

In this study, we used a commercial simulator to investigate the gasification characteristics of Roto coal in the partitioned fluidized-bed gasifier, which consists of 4 parts such as coal pyrolysis, char gasification, tar/oil gasification and char combustion. The heating medium was exchanged between the combustion part and the gasification part in order to supply the energy needed for pyrolysis and gasification. The correlation model from experimental data in relation to the reaction temperatures, the reaction gases and the coal feed rates was derived for the coal pyrolysis. The equilibrium model was used for the gasification and the combustion model for the char combustion. In order to compare the reaction behavior of the partitioned fluidized-bed gasifier, the single-bed gasifier was also simulated. The cold gas efficiency of both partitioned fluidized-bed gasifier and single-bed gasifier was almost the same. The $H_2$ and $CH_4$ contents of the syngas in the partitioned fluidized-bed gasifier slightly increased and the CO and $CO_2$ contents slightly decreased, compared with the singlebed gasifier. In order to verify the model, ten cases of the single-bed gasification experiment have been simulated. The contents of CO, $CO_2$, $CH_4$ in the syngas from the simulation corresponded with the experimental data while those of $H_2$ was slightly higher than experimental data, but the tendency of $H_2$ content in the syngas was similar to the experiments. In the coal conversion, the simulation results were higher than the experiments since equilibrium model was used for the gasification so that the residence time and contact time in the model is different from the experiments.

• Journal of Chest Surgery
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• v.34 no.12
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• pp.895-900
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• 2001

Background : This study aimed to evaluate the usefulness of preoperative placement of intraaortic balloon pump(IABP) in reducing operative risk and facilitating posterior vessel OPCAB in high risk patients with left main disease( 75％ stenosis), intractable resting angina, postinfarction angina, or left ventricular dysfunction(ejection fraction 35％). Material and Method : One hundred eighty- nine consecutive patients who underwent multi-vessel OPCAB including posterior vessel revascularization were studied. The patients were divided into group I(n=74) that received preoperative or intraoperative IABP and group II(n=115) that did not receive IABP. In group I, there were 39 patients with left main disease, 40 patients with intractable resting angina, 14 patients with left ventricular dysfunction and 7 patients with postinfarction angina. Ten patients received intraoperative IABP support due to hemodynamic instability during OPCAB. Result : There was one operative mortality in group I and two mortalities in group II. The average number of distal anastomoses was not different between group I and group II(3.5$\pm$0.9 vs 3.4$\pm$0.9, p=ns). There were no significant differences in the number of posterior vessel anastomosis per patient between the two groups. There were no differences in ventilator support time, length of hospital stay, and morbidity between the two groups. There was one case of IABP-related complication in group I. Conclusion : IABP facilitates posterior vessel OPCAB in high risk patients, with comparable surgical results to low risk patients

• Journal of Korean Society of Transportation
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• v.20 no.7
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• pp.15-22
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• 2002

Transportation project appraisal should be precise in order to increase the social welfare and efficiency, and it has been evaluated by only a single criterion analysis such as benefit/cost analysis. However, this method cannot assess some qualitative items, and cannot get a proper solution for the clash of interests among various groups. Therefore, the multi-criteria analysis, which can control these problems, is needed, and then Saaty has developed one of these methods, AHP(Analytic Hierarchy Process) method. In AHP, the project is evaluated through weighted score of the criteria and the alternatives, which is surveyed by a questionnaire of specialists. It is based on some strict suppositions such as reciprocal comparison, homogeneity, expectation, independence relationship between multi-criteria, but supposing that each criterion has independence relation with others is too difficult in two reasons. First, in real situation, there cannot be perfect independence relationship between standards. Second, individuals, even though they are specialists of that area, do not feel the degree of independence relation as same as others. This paper develops a modified AHP method for solving this dependence relationship between multi-criteria. First of all. in this method, the degree of dependence relationship between multi-criteria that the specialist feels is surveyed and included to the weighted score of multi-criteria This study supposes three methods to implement this idea. The first model products the degree of dependence relationship in the first step for calculating the weighted score, and the others adjust the result of weighted score from the basic AHP method to the dependence relationship. One of the second methods distributes the cross weighted score to each standard by constant ratio, and the other splits them using Fuzzy measure such as Bel and Pl. Finally, in order to validate these methods, this paper applies them to evaluate the alternatives which can control public resentments against Korean rail path in a city area.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.1
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• pp.77-81
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• 2009

Purpose: The PET of the PET/CT (Positron Emission Tomography/Computed Tomography) quantitatively shows the biological and chemical information of the body, but has limitation of presenting the clear anatomic structure. Thus combining the PET with CT, it is not only possible to offer the higher resolution but also effectively shorten the scanning time and reduce the noises by using CT data in attenuation correction. And because, at the CT scanning, the contrast media makes it easy to determine a exact range of the lesion and distinguish the normal organs, there is a certain increase in the use of it. However, in the case of using the contrast media, it affects semi-quantitative measures of the PET/CT images. In this study, therefore, we will be to establish the reliability of the SUV (Standardized Uptake Value) with CT data correction so that it can help more accurate diagnosis. Materials and Methods: In this experiment, a total of 30 people are targeted - age range: from 27 to 72, average age : 49.6 - and DSTe (General Electric Healthcare, Milwaukee, MI, USA) is used for equipment. $^{18}F$- FDG 370~555 MBq is injected into the subjects depending on their weight and, after about 60 minutes of their stable position, a whole-body scan is taken. The CT scan is set to 140 kV and 210 mA, and the injected amount of the contrast media is 2 cc per 1 kg of the patients' weight. With the raw data from the scan, we obtain a image showing the effect of the contrast media through the attenuation correction by both of the corrected and uncorrected CT data. Then we mark out ROI (Region of Interest) in each area to measure SUV and analyze the difference. Results: According to the analysis, the SUV is decreased in the liver and heart which have more bloodstream than the others, because of the contrast media correction. On the other hand, there is no difference in the lungs. Conclusions: Whereas the CT scan images with the contrast media from the PET/CT increase the contrast of the targeted region for the test so that it can improve efficiency of diagnosis, there occurred an increase of SUV, a semi-quantitative analytical method. In this research, we measure the variation of SUV through the correction of the influence of contrast media and compare the differences. As we revise the SUV which is increasing in the image with attenuation correction by using contrast media, we can expect anatomical images of high-resolution. Furthermore, it is considered that through this trusted semi-quantitative method, it will definitely enhance the diagnostic value.

• Radiation Oncology Journal
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• v.24 no.3
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• pp.171-178
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• 2006

[ $\underline{Purpose}$ ]: To determine the efficacy and safety of concurrent chemotherapy and radiation therapy with high-dose-rate brachytherapy for cervical cancer. $\underline{Materials\;and\;Methods}$: From January 2001 to December 2002, 30 patients with cervical cancer were treated with concurrent chemotherapy (cisplatin and 5-FU) and definitive radiation therapy. The median age was 58 (range $34{\sim}74$) year old. The pathology of the biopsy sections was squamous cell carcinoma in 29 patients and one was adenocarcinoma. The distribution to FIGO staging system was as follows: stage IB, 7 (23%); IIA, 3 (10%); IIB, 12 (40%); IIIA, 3 (10%); IIIB, 5 (17%). All patients received pelvic external beam irradiation (EBRT) to a total dose of $45{\sim}50.4\;Gy$ (median: 50.4 Gy) over $5{\sim}5.5$ weeks. Ir-192 HDR intracavitary brachytherapy (ICBT) was given after a total dose of 41.4 Gy. HDR-ICBT was performed twice a week, with a fraction point A dose of 4 Gy and median dose to point A was 28 Gy (range: $16{\sim}32\;Gy$) in 7 fractions. The median cumulative biologic effective dose (BED) at point A (EBRT+ICBT) was $88\;Gy_{10}$ (range: $77{\sim}94\;Gy_{10}$). The median cumulative BED at ICRU 38 reference point (EBRT+ICBT) was $131\;Gy_3$ (range: $122{\sim}140\;Gy_3$) at point A, $109\;Gy_3$ (range: $88{\sim}125\;Gy_3$) at the rectum and $111\;Gy_3$ (range: $91{\sim}123\;Gy_3$) at the urinary bladder. Cisplatin ($60\;mg/m^2$) and 5-FU ($1,000\;mg/m^2$) was administered intravenously at 3 weeks interval from the first day of radiation for median 5 (range: $2{\sim}6$) cycles. The assessment was performed at 1 month after completion of radiation therapy by clinical examination and CT scan. The median follow-up time was 36 months (range: $8{\sim}50$ months). $\underline{: The complete response rate after concurrent chemoradiation therapy was 93.3%. The 3-yr actuarial pelvic control rate was 87% and 3-yr actuarial overall survival and disease-free survival rate was 93% and 87%, respectively. The local failure rate was 13% and distant metastatic rate was 3.3%. The crude rate of minor hematologic complications (RTOG grade 1-2) occurred in 3 patients (10%) and one patient had suffered from severe leukopenia (RTOG grade 4) during concurrent treatment. Acute minor enterocolitis (RTOG grade 1-2) occurred in 11 patients (37%) and one patient (3%) was suffered from colon perforation during radiation therapy. Late colitis of RTOG grade 1 occurred in 5 patients (15%). Acute cystitis of RTOG grade 1 occurred in 12 patients (40%) and late cystitis of RTOG grade 2 occurred in one patient (3%). No treatment related death was seen. $\underline{Conclusion}$: The results of this study suggest that the concurrent chemoradiation therapy with HDR brachytherapy could be accepted as an effective and safe treatment for cervical cancer.

• The Korean Journal of Nuclear Medicine
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• v.36 no.4
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• pp.244-254
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• 2002

Purpose: This study investigated the differences between technetium-99m ethyl cysteinate dimer (Tc-99m ECD) and technetium-99m hexamethylpropylene amine oxime (Tc-99m HMPAO) uptake in the normal brain by means of statistical parametric mapping (SPM) analysis. Materials and Methods: We retrospectively analyzed age and sex matched 53 cases of normal brain SPECT. Thirty-two cases were obtained with Tc-99m ECD and 21 cases with Tc-99m HMPAO. There were no abnormal findings on brain MRIs. All of the SPECT images were spatially transformed to standard space, smoothed and globally normalized. The differences between the Tc-99m ECD and Tc-99m HMPAO SPECT images were statistically analyzed using statistical parametric mapping (SPM'99) software. The differences bgetween the two groups were considered significant ant a threshold of corrected P values less than 0.05. Results: SPM analysis revealed significantly different uptakes of Tc-99m ECD and Tc-99m HMPAO in the normal brains. On the Tc-99m ECD SPECT images, relatively higher uptake was observed in the frontal, parietal and occipital lobes, in the basal ganglia and thalamus, and in the superior region of the cerebellum. On the Tc-99m HMPAO SPECT images, relatively higher uptakes was observed in subcortical areas of the frontal region, temporal lobe, and posterior portion of inferior cerebellum. Conclusion: Uptake of Tc-99m ECD and Tc-99m HMPO in the normallooking brain was significantly different on SPM analysis. The selective use of Tc-99m ECD of Tc-99m HMPAO in brain SPECT imaging appears especially valuable for the interpretation of cerebral perfusion. Further investigation is necessary to determine which tracer is more accurate for diagnosing different clinical conditions.