• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.122-134
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• 2015

This study was conducted to investigate the potential of torrefied larch wood as a raw material of pellets. First of all, larch chip was torrefied at the temperatures of 230, 250 and $270^{\circ}C$ for 30, 50 and 70 min. Secondly, moisture content, moisture absorption, higher heating value and ash content of the torrefied chip were measured to examine the effects of torrefaction conditions on the fuel characteristics of larch. Thirdly, surfaces of the torrefied chip were observed by light microscope (LM), field emission scanning microscope (FE-SEM) and SEM-energy dispersive spectroscopy (EDXS). With the increases of torrefied temperature and time, contents of lignin increased and those of hemicellulose reduced. Moisture content of torrefied larch chip was greatly lower than that of non-torrefied chip. Moisture absorption of the torrefied chip decreased as torrefaction temperature increased. As torrefaction temperature increased, higher heating value and ash content of larch chip increased. However, durability of torrefied-larch pellets was remarkably lower comparing to non-torrefied-larch pellets. When surface of larch chip was observed by LM and FE-SEM, surface color and cell wall of the chip was getting darker and more collapsed with the increases of torrefaction conditions. Through the analysis of SEM-EDXS, distribution and quantity of lignin existing on the surface of larch chip increased with the increases of torrefied conditions. In conclusion, $270^{\circ}C$/50 min might be an optimal condition for the torrefaction of larch with the aspect of fuel characteristics, but torrefaction condition of $230^{\circ}C$/30 min should be considered according to the durability of torrefied-larch pellets.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.165-174
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• 2010

The numerical modeling of a coal gasification reaction occurring in an entrained flow coal gasifier is presented in this study. The purposes of this study are to develop a reliable evaluation method of coal gasifier not only for the basic design but also further system operation optimization using a CFD(Computational Fluid Dynamics) method. The coal gasification reaction consists of a series of reaction processes such as water evaporation, coal devolatilization, heterogeneous char reactions, and coal-off gaseous reaction in two-phase, turbulent and radiation participating media. Both numerical and experimental studies are made for the 1.0 ton/day entrained flow coal gasifier installed in the Korea Institute of Energy Research (KIER). The comprehensive computer program in this study is made basically using commercial CFD program by implementing several subroutines necessary for gasification process, which include Eddy-Breakup model together with the harmonic mean approach for turbulent reaction. Further Lagrangian approach in particle trajectory is adopted with the consideration of turbulent effect caused by the non-linearity of drag force, etc. The program developed is successfully evaluated against experimental data such as profiles of temperature and gaseous species concentration together with the cold gas efficiency. Further intensive investigation has been made in terms of the size distribution of pulverized coal particle, the slurry concentration, and the design parameters of gasifier. These parameters considered in this study are compared and evaluated each other through the calculated syngas production rate and cold gas efficiency, appearing to directly affect gasification performance. Considering the complexity of entrained coal gasification, even if the results of this study looks physically reasonable and consistent in parametric study, more efforts of elaborating modeling together with the systematic evaluation against experimental data are necessary for the development of an reliable design tool using CFD method.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.2
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• pp.153-160
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• 2009

A PM10 (aerodynamic diameter${\leq}$10 ${\mu}m$) sampler is used to quantify the potential human exposure to suspended particulate matter (PM) and to comply with the governmental regulation. This study was conducted to compare and evaluate the same PM10 cutpoint and different slopes between United States Environmental Protection Agency (USEPA) PM10 sampling criterion and American Conference of Governmental Industrial Hygienists/$Comit\acute{e}$ $Europ\acute{e}en$ de Normalization/International Organization for Standardization thoracic PM10 sampling criterion through theory and experiment. Four PM10 samplers according to the USEPA criterion and one RespiCon sampler in accordance with the thoracic PM10 criterion were used in the present study. In addition, one DustTrak monitor was used to measure real time PM10 mass concentrations. All six aerosol samplers were tested in a PM generation chamber using polydisperse fly ash. Theoretical mass concentrations were calculated by applying the measured particle size distribution characteristics (geometric mean = 6.6 ${\mu}m$, geometric standard deviation = 1.9) of fly ash to each sampling criterion. The measured mass concentrations through a chamber experiment were consistent with theoretical mass concentrations in that a RespiCon sampler with the thoracic PM10 criterion collected less PM than a PM10 sampler with the USEPA criterion. The overall chamber experiment results indicated, when a PM10 sampler was used as a reference sampler, that (1) a RespiCon sampler had a normalizing factor of 1.6, meaning that this sampler underestimated an average 60% of PM10 mass sampled from a PM10 sampler, and (2) a DustTrak real-time monitor using a PM10 inlet had a calibration factor of 2.1.

• Journal of Gastric Cancer
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• v.6 no.1
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• pp.31-35
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• 2006

Purpose: A primary adenosquamous carcinoma of the stomach is relatively rare, accounting for only about 0.5% of all gastric cancers. However, its histopathologic characteristics are still unclear, and the most appropriate form of therapy has not been established yet. Materials and Methods: We retrospectively reviewed the clinicopathologic features of 8 patients with pathologically confirmed primary adenosquamous carcinomas out of 8,268 patients who underwent gastric cancer surgery at Samsung Medical Center between September 1994 and December 2004. Results: The median age of the 8 patients was 49 ($41{\sim}69$) years, and the male : female ratio was 5 : 3. In 3 patients, the tumor was located at the mid body of the stomach, and in 5 patients, at the lower body or antrum. The tumor sizes were $2.5{\sim}8cm$. Seven patients showed metastases to the regional lymph nodes. The UICC stage distribution were: 5 stage II, 2 stage III, and 1 stage IV. In the stage IV patient, a palliative gastrojejunostomy was performed, and he died 5 months after surgery. Of the 7 patients who underwent a radical gastrectomy and adjuvant chemotheratpy, the median survival was 34 ($12{\sim}66$) months, 2 patients died of cancer recurrence, and 4 patients are being followed up without evidence of recurrence. Conclusion: As for an adenocarcinoma of the stomach, a radical gastrectomy including regional lymph node dissection and postoperative adjuvant therapy should be performed for appropriate treatment of an adenosquamous carcinoma of the stomach.

• Tuberculosis and Respiratory Diseases
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• v.47 no.3
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• pp.331-338
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• 1999

Background: Nearly 10% of cancer patients will develop a second primary cancer within ten years after surgical removal of the primary tumor. The detection of risk factors for developing multiple primary tumors would be important This study was conducted to evaluate the clinical characteristics and abnormal p53 expression of lung cancer associated with multiple primary cancer(MPC). Method: Clinical characteristics and abnormal p53 expression were compared between 20 cases of lung cancer(NSCLC ; 16 cases, SCLC ; 4 cases) associated with MPC and 26 cases of primary non-small cell lung cancer. Result: MPC associated with lung cancer was gastric cancer(8), lung cancer(2), esophageal cancer(2), colon cancer(2), laryngeal cancer(1), bladder cancer(1), small bowel cancer(l), adrenal cancer(1), hepatocellular carcinoma(1), and breast cancer (1) in order. The clinical stage of primary NSCLC was relatively advanced, but NSCLC associated with MPC was even distribution at each stage. The detected incidences of abnormal p53 expressions were 62.5% in NSCLC associated with MPC and 76.9% in primary NSCLC(p>0.05). Conclusion: There was no difference in abnormal p53 expression between non-small cell carcinoma associated with multiple primary cancer and primary non-small cell carcinoma.

• Tuberculosis and Respiratory Diseases
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• v.54 no.5
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• pp.563-569
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• 2003

Background : Pleural effusions with high amylase levels are reported frequently in patients with pancreatic diseases, a rupture of the esophagus and a malignancy. However, there is no data available on the clinical features of an amylase-rich pleural effusion in Korea. This report describes the causes of the high amylase levels in a pleural effusion and analyzes its association with malignancy. Methods : The records of patients with an amylase-rich pleural effusion who were assessed at the Gyeongsang National University Hospital from January 1998 to August 2002 were examined retrospectively, and the distribution of amylase levels in those patients, the causative diseases, and the histological type in the case of a malignancy were analyzed. Among the 532 patients whose pleural effusion was evident on a chest X-ray, there were 36 cases with an amylase-rich pleural effusion. The amylase levels were determined by an enzyme method (Hitach 747 autoanalyzer). Results : Of the 36 patients with an amylase-rich pleural effusion, there were 18 patients(50%) associated with a malignancy, 8 patients(22%) with a parapneumonic effusion, 7 patients(19%) with pancreatic disease, and 3 patients with other causes. The amylase level in a pleural effusion due to pancreatic disease was much higher than that due to other causes(p<0.01). Among the malignant pleural effusions with high amylase levels, the origin of the malignancy was a primary lung cancer in 13 cases and metastatic lung cancer in 5 cases. The histological types of malignant causes were adenocarcinoma in 10 cases(56%), squamous cell carcinoma in 2 cases(11%) and unknown type of carcinoma in 6 cases. The amylase level in the adenocarcinoma cases was much higher than that in the other cell type carcinomas(p<0.01). There was no significant association between the amylase level and the glucose level among the malignant cases with amylase-rich pleural effusion(p=0.21). Conclusion : The most frequent cause of an amylase-rich pleural effusion was a malignancy. Primary lung cancer and adenocarcinoma were the most common malignancies and histological types associated with a malignant pleural effusion with high amylase levels. The amylase level in a pleural effusion secondary to pancreatic disease was much higher than from any other causes.

• Restorative Dentistry and Endodontics
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• v.33 no.4
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• pp.352-368
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• 2008

This study was done to evaluate the reliability of the digital color analysis system (ShadeScan, CYNOVAD, Montreal. Canada) for dentistry. Sixteen tooth models were made by injecting the A2 shade chemical cured resin for temporary crown into the impression acquired from 16 adults. Surfaces of the model teeth were polished with resin polishing cloth. The window of the ShadeScan handpiece was placed on the labial surface of tooth and tooth images were captured, and each tooth shade was analyzed with the ShadeScan software. Captured images were selected in groups, and compared one another. Two models were selected to evaluate repeatability of ShadeScan, and shade analysis was performed 10 times for each tooth. And, to ascertain the color difference of same shade code analyzed by ShadeScan, CIE $L^*a^*b^*$values of shade guide of Gradia Direct (GC, Tokyo, Japan) were measured on the white and black background using the Spectrolino (GretagMacbeth, USA), and Shade map of each shade guide was captured using the ShadeScan. There were no teeth that were analyzed as A2 shade and unique shade. And shade mapping analyses of the same tooth revealed similar shade and distribution except incisal third. Color difference (${\Delta}E^*$) among the Shade map which analyzed as same shade by ShadeScan were above 3. Within the limits of this study, digital color analysis instrument for dentistry has relatively high repeatability, but has controversial in accuracy.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.1
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• pp.19-26
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• 2017

Purpose: The application of density override is very important to minimize dose calculation errors by fiducial markers of metal material in proton treatment plan. However, density override with actual material of the fiducial marker could make problem such as inaccurate target contouring and compensator fabrication. Therefore, we perform density override with surrounding material instead of actual material and we intend to evaluate the usefulness of density override with surrounding material of the fiducial marker by analyzing the dose distribution according to the position, material of the fiducial marker and number of beams. Materials and Method: We supposed that the fiducial marker of gold, steel, titanium is located in 1.5, 2.5, 4.0, 6.0 cm from the proton beam's end of range using water phantom. Treatment plans were created by applying density override with the surrounding material and actual material of the fiducial marker. Also, a liver cancer patient who received proton therapy was selected. We located the fiducial marker of gold, steel, titanium in 0, 1.5, 3.5 cm from the proton beam's end of range and the treatment plans were created by same method with water phantom. Homogeneity Index(HI), Conformity Index(CI) and maximum dose of Organ At Risk(OAR) in Planning Target Volume(PTV) as the evaluation index were compared according to the material, position of the fiducial marker and number of beam. Results: The HI value was more decreased when density override with surrounding material of the fiducial marker was performed comparing with density override with actual material. Especially the HI value was increased when the fiducial marker was located farther from the proton beam's end of the range for a single beam and the fiducial marker's position was closer to isocenter for two or more beams. The CI value was close to 1 and OAR maximum dose was greatly reduced when density override with surrounding material of the fiducial marker was performed comparing with density override with actual material. Conclusion: Density override with surrounding material can be expected to achieve more precise proton therapy than density override with actual material of the fiducial marker and could increase the dose uniformity and target coverage and reduce the dose to surrounding normal tissues for the small fiducial markers used in clinical practice. Most of all, it is desirable to plan the treatment by avoiding the fiducial marker of metal material as much as possible. However, if the fiducial marker have on the beam path, density override of the surrounding material can be expected to achieve more precise proton therapy.

• Radiation Oncology Journal
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• v.13 no.3
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• pp.215-223
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• 1995

Purpose : The aim of this study was to assess the effectiveness, survival rate and complication of radiation in nasopharyngeal cancer. Materials and Methods : From January 1980 to May 1989. Fifty patients who had nasopharyngeal carcinoma treated with curative radiation therapy at Kosin Medical Center were retrospectively studied. Thirty seven patients($74{\%}$) were treated with radiation therapy alone(Group I) and 13 patients ($26{\%}$) treated with combination of chemotherapy and radiation (Group II). Age distribution was 16-75 years(median : 45.8 years). In histologic type, squamous cell carcinoma was in 30 patients($60{\%}$), undifferentiated carcinoma in 17 patients($34{\%}$), and lymphoepithelioma in 3 patients($6{\%}$). According t AJCC staging system. 4 patients($8{\%}$) were in $T_1$, 13 patients($26{\%}$) in $T_2$. 20 patients($40{\%}$) in $T_3$, 13 patients($26{\%}$) in $T_4$ and 7 patients($14{\%}$) in $N_0$, 6 patients($12{\%}$) $N_1$, 23 patients($46{\%}$) in $N_2$, 14 patients($28{\%}$) in $N_3$. Total radiation dose ranges were 5250-9200cGy(median : 7355 cGy) in Group I and 5360-8400cGy(median : 6758cGy) in Group II Radiotherapy on 4-6MV linear accelerator and/or 6-12MeV electron in boost radiation was given with conventional technique to 26 patients($52{\%}$), with hyperfractionation(115-120cGy/fr., 2times/day) to 16 patients($32{\%}$), with accelerated fractionation(160cGy/fr., 2 times/day) to 8 patients($16{\%}$). In chemotherapy, 5 FU 1000mg daily for 5 consecutive days, pepleomycin 10mg on days 1 and 3, and cisplatin 100mg on day 1 were administered with 3weeks interval, total 1 to 3 cycles(average 1.8cycles) prior to radiation therapy. Follow up duration was 6-140 months(mean : 58 months). Statistics was calculated with Chi-square and Fisher's exact test. Results : Complete local control rates in Group I and II were $75.7{\%},\;69.2{\%} Overall 5 year survival rates in Group I and II were $56.8{\%},\;30.8{\%}$. Five year survival rates by histologic type in Group I and II were $52.2{\%},\;14.3{\%}$ is squamous cell carcinoma and $54.5{\%},\;50{\%}$ in undifferentiated carcinoma. Survival rates in Group I were superior to those of Group II though there were not statistically significant. In both group, survival rates seem to be increased according to increasing total dose of radiation up to 7500cGy, but not increased beyond it. There were not statistically significant differences in survival rates by age, stage, and radiation techniques in both group. Twenty four patients($48{\%}$) experienced treatment failures. Complications were found in 12 patients($24{\%}$). The most common one was osteomyelitis(4 patients, $33.3{\%}$) involving mandible (3 patients) and maxilla(1 patient). Conclusion : Chemotherapy in combination with radiotherapy was found to be not effective to nasopharyngeal cancer and the survival rate was also inferior to that of radiation alone group though it was statistically not significant due to small population in chemotherapy combined group.

• Radiation Oncology Journal
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• v.28 no.2
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• pp.79-84
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• 2010

Purpose: We retrospectively analyzed the long-term results of radical surgery and intraoperative radiation therapy (IORT) in patients with stomach cancer. Materials and Methods: From 1988 to 1994, 51 patients were treated with curative surgery and IORT. Postoperative external beam radiotherapy (EBRT) was administered to 30 patients, while adjuvant chemotherapy was administered to 35 patients. A dose of 15 Gy was irradiated with a 9 MeV electron beam as the IORT and a median dose of EBRT was 43.2 Gy (range, 7.2 to 45 Gy). The follow-up period ranged from 1~254 months, with a median follow-up period of 64 months. Results: The median age of all the patients was 58 years (range, 30 to 71 years). The distribution of pathologic stage (American Joint Committee on Cancer [AJCC] 2002 tumor-note-metastasis [TNM]) was as follows: 13 stage I (25.5%), 10 stage II (19.6%), 25 stage III (49.0%), and 3 stage IV (5.9%). Distant metastases occurred in 11 patients (10 in the peritoneum and 1 in bone), including one patient with concurrent local recurrence (anastomosis site). The 5-year locoregional control, disease free survival and overall survival rates were 94.7%, 66.5%, and 51.7%, respectively. For the multivariate analysis, age, TNM stage, and EBRT were significant prognostic factors for overall survival, and only TNM stage for disease free survival. Conclusion: We could have achieved a high loco-regional control rate in patients with locally advanced stomach cancer by adding IORT to radical surgery. However, the benefit of IORT on survival remains to be elucidated.