• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.832-839
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• 1992

Lead has been determined by Resonance Ionization Mass Spectrometry (RIMS) through one-color-two-photon ionization, two-color-two-photon ionization and three-color-three-photon ionization in a vacuum chamber equipped with Time-of-Flight(TOF) mass spectrometer. In all cases, the first excited state chosen was 6p7s($^3P_1$) state and the transition was at 283.3 nm in wavelength from the ground state. By using various concentrations of lead standard solutions, the calibration curve is obtained in the range of 0.1 ${\mu}g$ to 1.0 pg in both ionization schemes. The detection limit was estimated as 20 pg for the two-color ionization, while 10 pg for the three-color ionization experiment.

• Journal of Gastric Cancer
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• v.13 no.1
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• pp.34-43
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• 2013

Purpose: The intracorporeal reconstruction after laparoscopic gastrectomy can minimize postoperative pain, and give better cosmetic effect, while it may have technical difficulties and require the learning curve. This study aimed to analyze the surgical outcome of intracorporeal reconstruction according to the surgeon's experience comparing with extracorporeal procedure. Materials and Methods: From January 2009 to September 2011, intracorporeal reconstruction in laparoscopic surgery for gastric cancer was performed for 71 patients (Intra group). During same period, 231 patients underwent laparoscopy-assisted gastrectomy (Extra group). These patients were classified into initial (1st to 20th case of intra group), intermediate (21th to 46th case), and experienced (after 47th case) phases. Results: Intracorporeal procedures included 35 cases of Billroth-I, 30 Billroth-II and 6 Roux en Y reconstructions. In the initial phase, operation time (P=0.022) were significantly longer for the patients of intra group than them of extra group. Although the difference was not significant, the length of hospital stay was longer and complication rate was higher in the intra group. In intermediate and experienced phases, there was no difference between two groups in operation time and hospital stay. In these phases, complication rate was lower in the intra group than the extra group (3.9% versus 9.7%). The pain scale was significantly lower post operation day 5 in the intra group. Conclusions: Intracorporeal reconstruction after laparoscopic distal gastrectomy was feasible and safe, and the technique was stabilized after 20th case if the surgeon has sufficient experiences when we compared it with extracorporeal reconstruction.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.27 no.3
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• pp.251-257
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• 2023

Backgrounds/Aims: This is a retrospective analysis of whether the 8th edition American Joint Committee on Cancer (AJCC) was a significant improvement over the 7th AJCC distal extrahepatic cholangiocarcinoma classification. Methods: In total, 111 patients who underwent curative resection of mid-distal bile duct cancer from 2002 to 2019 were included. Cases were re-classified into 7th and 8th AJCC as well as clinicopathological univariate and multivariate, and Kaplan-Meier survival curve and log rank were calculated using R software. Results: In patient characteristics, pancreaticoduodenectomy/pylorus preserving pancreaticoduodenectomy had better survival than segmental resection. Only lymphovascular invasion was found to be significant (hazard ratio 2.01, p = 0.039) among all clinicopathological variables. The 8th edition AJCC Kaplan Meier survival curve showed an inability to properly segregate stage I and IIA, while there was a large difference in survival probability between IIA and IIB. Conclusions: The 8th distal AJCC classification did resolve the anatomical issue with the T stage, as T1 and T3 showed improvement over the 7th AJCC, and the N stage division of the N1 and N2 category was found to be justified, with poorer survival in N2 than N1. Meanwhile, in TMN staging, the 8th AJCC was able differentiate between early stage (I and IIA) and late stage (IIB and III) to better explain the patient prognosis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2879-2887
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• 2011

This research is aimed for the better understanding of corrosion behavior of carbon steel in ETA or $NH_3$ solution at high temperature. To minimize the corrosion it is important to select proper pH control agent(s), which also let it maintain basic or reductive environment inside the steel pipe. This work will provide the practical guideline which can be applied to the nuclear power plant for developing the life extension method of carbon steel. Experiments were carried out by measuring the corrosion rate using the potentiodynamic polarization curve of carbon steel in ETA and NH3 at different temperatures. The corrosion rate was estimated by using the Tafel curve measured under various test conditions: i) $NH_3$ is less than ETA as a pH agent. ii) the corrosion was reduced at high pH, and iii) the corrosion was maximum in the temperature range of $150\sim200^{\circ}C$.

• The Journal of Korean Society for Radiation Therapy
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• v.34
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• pp.13-20
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• 2022

Purpose : IMRT using Tomotherapy during nasopharyngeal cancer radiation therapy irradiate an accurate dose to tumor tissues and is effective to reduce a dose rapidly in normal tissues. However, this has high MU and long Beam On Time. This study aims to analyze differences in tumors, normal tissues and low-dose distributions and the efficiency of Split VMAT after applying Helical IMRT (Tomotherapy), VMAT (Linac : 2Arc) and Split VMAT (Linac : 4Arc) plans. Materials and Methods : This study targeted ten nasopharyngeal cancer patients of this hospital and compared three treatment plans (Helical IMRT, VMAT, Split VMAT). For Helical IMRT planning, Precision^® (Version 1.1.1.1, Accuray, USA) was used, and for VMAT and Split VMAT planning, Pinnacle^3® (Version 9.10, Philips, USA) was used. The total dose applied was 38.4 Gy / 32 Gy (Daily Dose 2.4 Gy (GTV + 0.3 cm) / 2 Gy (CTV + 0.3 cm) 16Fx), and for GTV + 0.3 cm (P_GTV), 95% of V_38.4Gy was prescribed. VMAT with an angle of 360° 2Arc was applied, and for Split VMAT, the field was divided into the right, the left, the top and the bottom and an angle of 360° 4Arc, 6MV was set. For evaluating the quality of the treatment plans, differences in tumors, normal tissues and low-dose area were compared, and Beam On Time was measured to analyze the efficiency. Results : When calculating the mean values of evaluation items of the three treatment plans (Helical IMRT, VMAT, Split VMAT) for the patients, the H.I (Homogeneity Index) of P_GTV was 1.04, 1.11 and 1.1 respectively, and the C.I (Confomity Index) of P_CTV was 1.03, 0.99 and 1.00 respectively. The mean dose of RT Parotid Gland (Gy) was 14.54, 17.06 and 14.76 respectively, the mean dose of LT Parotid Gland (Gy) was 14.32, 17.32 and 15.09 respectively, the maximum dose of P_Cord (Spinal Cord + 0.3 cm) (Gy) was 20.57, 22.59 and 21.06 respectively, and the maximum dose of Brain Stem (Gy) was 22.35, 23.99 and 21.68 respectively. The 50% isodose curve (cc) was 1332, 1132.5 and 1065.2 respectively. Beam On Time (sec) was 373.7, 130.7 and 254.4 respectively. Conclusion : Displaying a similar treatment plan quality to Helical IMRT, which is used a lot for head and neck treatment, Split VMAT reduced the low-dose area and Beam On Time and produced a better result than VMAT. Therefore, it is considered that Split VMAT is effective not only for nasopharyngeal cancer but also for other head and neck cancers.

• 전기의세계
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• v.23 no.4
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• pp.46-52
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• 1974

Generally, it has been regarded that there are two kinds of the effect of the electrodes, especially of the cathode in the gas discharge, (a) the effect caused by the difference of the cathode meterial and (b) the effect by the change of the cathode surface state even in the same meterials. Thus the two effects must be investigated independently to study the roles of the cathode in gas discharges. This paper measured sparking voltage in Rare gas (Ar, He) for the change of sparking voltage in repeating sparks and for the effect of (a) and (b) mentioned above, under the condition that the desorption of impurities from the cathod can be nigligible, and it is obtained that the correlative relations of the work function, sparking voltage and secondary coefficient are comparatively simple. In addition, the interesting character of the minimum point of the paschen's curves is found. The results were as follows; 1) The value of (pd)min with minimum pint of sparking voltage, (Vs)min, is 0.7-0.9 Torr. cm in Argon, but is 5.6-7.1 Torr. cm in Helium, and Paschen's curve in Helium shows slow curve than in Argon. 2) The minimum point of the Paschen's curve is satisfied actually Townsend's self sustaining criterion in Argon, but non-satisfaction in Helium, and the Townsend's secondary coefficient .gamma. action have compound property (.gamma.$_{i}$, .gamma.$_{p}$, .gamma.$_{m}$) in Helium. 3) The dependenting character of work function in Helium is less than in Argon. 4) The minimum point of sparking voltage increase under oxidized electrode than clear electrode in Au and Ag, but minimum point decrease in Ni and Cu.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.5
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• pp.750-757
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• 2003

In order to determine creep stress intensity limit of high-temperature components, the usefulness of the creep work and time equation, defined as W$\_$c/t$\^$p/ = B(where W$\_$c/ = $\sigma$$\varepsilon$ is the total creep work done during creep, and p and B are constants), was investigated using the experimental data. For this Purpose, the creep tests for generating 1.0% strain for commercial type i16 stainless steel were conducted with different stresses; 160 MPa, 150 MPa, 145 MPa, 140 MPa and 135 MPa at 593$^{\circ}C$. The plots of log W$\_$c/ - log t showed a good linear relation up to 10$\^$5/ hr, and the results of the creep work-time relation for p, B and stress intensity values showed good agreement to those of isochronous stress-strain curves (ISSC) presented in ASME BPV NH. The relation can be simply obtained with only several short-term 1% strain data without ISSC which can be obtained by long-term creep data. Particularly, this relation is useful in estimating stress intensity limit for new and emerging class of high-temperature creeping materials.

• Korean Journal of Microbiology
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• v.5 no.2
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• pp.93-96
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• 1967

Especially, we mainly dealt on the isolation of mold in the sample of the Korean products, Kock Ja. The kinds of the isolated strain are such as these, Rhizopus, Mucor, Aspergillus oryzae sp., aspergillus niger sp., Penicillum and Flungi Imperfecti. The action of the starch saccharification of isolated strain and the order of liquefying action are follows: The saccharification power was R-l>R-2>M-2> Kock Ja>M-1>O-2>N-1>O-4 The liquefying power was R-1, R-2>0-2>0-4>M-2, Kock Ja>M-1>N-1 We compared the pH's saccharification curve of each kind of strain with Kock Ja. The most suitable pH value of R-1, R-2 was the closest to pH 4. 0, close value with Kock Ja. The Rhizopus species on the saccharification action of each kind of strain in regard to raw wheat starch was stronger than other kinds of strain. We think that to generalize the above result, the Rhizopus species consists of an important strain of this Kock Ja, and is an important factor for the saccharification action of Kock Ja and the existence of Mucor species as well.

• Radiation Oncology Journal
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• v.12 no.3
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• pp.301-305
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• 1994

Purpose :. To investigate the effect of aqueous extract of Ganoderma lucidum(G.I.) on the surival of tumor cells in vitro and on the growth of tumors in vivo. Materials and Methods : Dried G.I. was made into powder, extracted with distilled water, filtered and diluted from a maximum concentration of 100 mg/ml in sequence. The cytotoxicity of G.I, in vitro was evaluated from its ability to reduce the clonogenicity of SCK tumor cells. For the tumor growth delay study, about $2{\times}10^5$$ of SCK tumor cells were subcutaneously inoculated in the legs of A/J mice. The first experimental group of mice were injected i.p. with 0.2ml of 250 mg/kg of G.I. from the first day after tomor inoculation for 10 days. The second experimental group of mice were injected i.p. with 0.2ml of 250 mg/kg of G.I. either once a day for 10 days or twice a day for 5 days beginining from the 7th day after tumor inoculation Results : 1. Cytotoxicity in vitro;survival fraction, as judged from the curve, at G.I. concentration of 0.5, 1,5, 10, 25, 50 and 100 mg/ml were 1.0, $0.74{\pm}0.03$, $0.18{\pm}0.03$, $0.15{\pm}0.02$, $0.006{\pm}0.002$, 0.015 and 0.0015, respectively. 2. Tumor growth delay in vivo; a) the time required for the mean tumor volume to grow to $1,000mm^3$ was 11 days in the control group and 14 days in the experimental group. b) the time required for tumor volume to increase 4 times was 11 days in the control group while it was 10.5 and 12 days in the groups injected with G.I. once a day and twice a day from the 7th day after tumor inoculation respectively. Conclusion : Aqueous extracts of G.I. showed a marked cytotoxicity on the SCK mammary cells in vitro. Tumor growth delay was statistically signiricant when G.I. in-jection was started soon after tumor inoculation, but it was not significant when injection was started after the tumors were firmly established.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.2
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• pp.415-433
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• 1998

Digora system is an intraoral indirect digital radiography system utilizing storage phosphor image plate. It has wide dynamic range which allows it to decrease the patient s exposure time and may increase diagnostic ability through image processing (such as edge enhancement, grey scale conversion, brightness change, and contrast enhancement). And also, it can transmit and storage image information. The purpose of this study was to evaluate the diagnostic ability of artificial proximal caries between Conventional radiograph and Digora images(unenhanced image, brightness & contrast controlled image, and edge enhanced image). ROC(Receiver Operating Characteristic) analysis, paired t-tests, and F-tests were done for the statistical evaluation of detectability. The following results were acquired: 1. In Grade I lesions, the mean ROC areas of Conventional radiograph, Digora unenhanced image, Digora controlled image, and Digora edge enhanced image were 0.953, 0.933, 0.965, 0.978 (p>0.05). 2. In Grade II lesions, the mean ROC areas of Conventional radiograph, Digora unenhanced image, Digora controlled image, and Digora edge enhanced image were 0.969, 0.964, 0.988, 0.994. Among theses areas, there was just statistical significance between Diagnostic abilities of Digora edge enhanced image and Conventional radiograph (p<0.05). 3. In the Interobserver variability, the ROC curve areas of Digora edge enhanced image was lowermost in these areas, regardless of the Carious lesion depths. In conclusion, intraoral indirect digital system, Digora system, has the potential possibility as an alternative of Conventional radiograph in the diagnosis of proximal caries.