• Radiation Oncology Journal
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• v.33 no.1
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• pp.12-20
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• 2015

Purpose: To evaluate treatment outcomes and determine prognostic factors in patients with esophageal cancer treated with esophagectomy after neoadjuvant chemoradiotherapy (NCRT) Materials and Methods: We retrospectively evaluated 39 patients with esophageal cancer who underwent concurrent chemoradiotherapy followed by esophagectomy between 2002 and 2012. Initial clinical stages of patients were stage IB in 1 patient (2.6%), stage II in 5 patients (12.9%), and stage III in 33 patients (84.6%). Results: The median age of all the patients was 62 years, and the median follow-up period was 17 months. The 3-year overall survival (OS) rate was 33.6% in all the patients. The 3-year locoregional recurrence-free survival (LRFS) rate was 33.7%. In multivariate analysis with covariates of age, the Eastern Cooperative Oncology Group performance status, hypertension, diabetes mellitus, tumor length, clinical response, clinical stage, pathological response, pathological stage, lymphovascular invasion, surgical type, and radiotherapy to surgery interval, only pathological stage was an independent significant prognostic factor affecting both OS and LRFS. The complications in postoperative day 90 were pneumonia in 9 patients, anastomotic site leakage in 3 patients, and anastomotic site stricture in 2 patients. Postoperative 30-day mortality rate was 10.3% (4/39); the cause of death among these 4 patients was respiratory failure in 3 patients and myocardial infarction in one patient. Conclusion: Only pathological stage was an independent prognostic factor for both OS and LRFS in patients with esophageal cancer treated with esophagectomy after NCRT. We could confirm the significant role of NCRT in downstaging the initial tumor bulk and thus resulting in better survival of patients who gained earlier pathological stage after NCRT.

• Proceedings of the Korean Magnestics Society Conference
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• 2011.06a
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• pp.7-8
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• 2011

Basically, the lattice mismatch between film and substrate can make those BiFeO3(BFO) films distorted with strain structure. BFO phase can be stabilized on LaAlO3(LAO) represents the example of a multiferroic with giant axial ratio. Its crystal structure is not strictly tetragonal, but tetragonal with a slight monoclinic distortion and related to the rotation of the oxygen octahedra. In this study, we show that phases with a tetragonal-like epitaxial BFO films can indeed be ferroelectric and also can be stabilized via epitaxial growth onto LAO. Recent reports on epitaxial BFO films show that the crystal structure changes from nearly rhombohedral ("R-like") to nearly tetragonal("T-like") at strains exceeding approximately -4.5%, with the "T-like" structure being characterized by a highly enhanced c/a ratio. While both the "R-like" and the "T-like" phases are monoclinic, our detailed x-ray diffraction results reveal asymmetry change from MA and MC type, respectively. By applying additional strain or by modifying the unit cell volume of the film by substituting Ba for Bi, the monoclinic distortion in the "T-like" MC phase is reduced, i.e. the system approaches a true tetragonal symmetry. There are two different M-H loops for $Bi_{1-x}Ba_xFeO_{3-{\delta}}$(BBFO) and BFO films on SrTiO3(STO) & LAO substrates. Along with the ferroelectric characterization, these magnetic data indicate that the BFO phase stabilized on LAO represents the first example of a multiferroic with giant axial ratio. However, there is a significant difference between this phase and other predicted ferroelectrics with a giant axial ratio: its crystal structure is not strictly tetragonal, but tetragonal with a slight monoclinic distortion. Therefore, in going from bulk to highly-strained films, a phase sequence of rhombohedral(R)-to-monoclinic ["R-like" MA-to-monoclinic, "T-like" MC-to-tetragonal (T)] is observed. This sequence is otherwise seen only near morphotropic phase boundaries in lead-based solid-solution perovskites (i.e. near a compositionally induced phase instability), where it can be controlled by electric field, temperature, or composition. Our results show that this evolution can occur in a lead-free, stoichiometric material and can be induced by stress alone. Those major results are summarized as follows ; 1) Ba-doping increases the unit cell volume, 2) BBFO on LAO can be fully strained up to x=0.08 as a strain limit (Fig. 1), 3) P(E) & M(H) properties can be tuned by the variation of composition, strain, and film thickness.

• Journal of Radiation Protection and Research
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• v.21 no.1
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• pp.1-7
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• 1996

In this paper, we discussed the fabrication and characterization of bulk type CdZnTe detector for pocket surveymeter. The resistivity of CdZnTe single crystal grown by the High Pressure Bridgman method is in the mid of $10^9$ ohm-cm. The detector structure is Au/CdZnTe/Au and gold electrode is formed by electroless deposition method. Resolutions of 4.8keV and 2.2keV were observed at 22.2keV line of $^{109}Cd$ and 59.6keV line of $^{241}Am$ at room temperature, respectively. We also constructed the small size pocket surveymeter using home made CdZnTe detector. It shows the good linearity over a range from 1mR/hr to 10R/hr with deviation less than 5%. The sensitivity of the surveymeter developed is $2.2{\times}10^3 cps/Rad\;hr^{-1}$ for the 662keV of $^{l37}Cs\;{\gamma}-ray$.

• The Journal of the Petrological Society of Korea
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• v.15 no.1 s.43
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• pp.10-24
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• 2006

Staurolite grains in staurolite, kyanite and sillimanite zones occurred in the Littleton Formation, Northcentral Massachusetts have interpreted to form by Barrovian-type metamorphism during Acadian orogeny. However, various occurrence of staurolite in the three zones, (a) porphyroblast, (b) randomly oriented and coarse-grained muscovite pseudomorph after staurolite, (c) recrystallized staurolite at the margin of garnet porphyroblast and within the pseudomorph, indicates that they have resulted from polymetamorphism. Staurolite in these three metamorphic zones can be formed by demise of chlorite or chloritoid that depends on difference of bulk-rock compositions and changes of P-T conditions. Staurolite modal proportion calculated in MnNCKFHASH system using THERMOCALC program reveals that staurolite could have grown with garnet with increasing pressure and temperature, if it coexist with chlorite. After demise of chlorite and appearance of biotite, staurolite mode decrease with increasing pressure and temperature. Therefore, based on the previous P-T paths for the Acadian metamorhism, staurolite porphyroblast grew with garnet during 400-370 Ma. Randomly oriented and coarse-grained muscovite pseudomorphs after staurolite probably have grown due to heating with appearance of kyanite and sillimanite. Consequently, pseudomorphisrn of staurolite occurred by heating derived from locally intense Alleghanian shearing (ca. 320-300 Ma) overprinted the Acadian metamorphism. Recrystallized fine-grained staurolite in sillimanite zone observed between the grain boundaries of muscovite in the pseudomorphs and at the edge of garnet porphyrobasts has formed during decreasing temperature and pressure (ca. 300-280 Ma) after peak temperature (ca. $700^{\circ}C$) of the Allegllanian metamorphism.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.2
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• pp.168-179
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• 1994

In some ceramic industries, worker exposure to dust, crystalline free silica and lead were determined and evaluated. The conclusions are as follows. 1. Crystalline silica in bulk samples was 10.5 % in sanitary ware industry, 9.4 % in tile industry, and 2.1 % in ceramic insulator industry respectively. The free silica content of air filter sample was 8.03 % in table ware industry, 5.59 % in sanitary ware industry, and 1.32 % in ceramic insulator industry. Because silica content in ceramic dust is relatively high, it is should be considered silica as important factor in evaluating for ceramic industry. 2. The silica contents in dust from tile, sanitary ware and table ware industries are above 5%, it should be classified as "Type" 2 dust. 3. The airborne concentration of respirable crystalline silica was $27.9{\mu}g/m^3$ in a sanitary ware factory and $5.8{\mu}g/m^3$ in a ceramic insualtor factory. Three of ten samples sampled the above factories were exceeded the occupational exposure levels, $100{\mu}g/m^3$. 4. Geometric mean(GM) of total dust in 11 factories was $1.00mg/m^3$ and GM of respirable dust concentration in 5 factories was $0.33mg/m^3$. Sanitary ware industry had the highest concentration of total dust, $1.62mg/m^3$ and of respirable dust, $0.88mg/m^3$. 5. Average lead concentration in air was $0.05mg/m^3$ in glazing process of 2 factories manufacturing table ware. Five of ten sample(50%) were exceeded $0.05mg/m^3$. Therefore lead exposure in pottery industry should be considered as important problem.

• Journal of the Korean Society of Groundwater Environment
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• v.5 no.3
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• pp.155-161
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• 1998

Retardation effect of heavy metals in soils caused by adsorption onto the surfaces of solids particles is well known phenomenon. In this study, we investigated the retardation effect on the mobility of a Zn in a sandy soil by conducting batch and column tests. The column test consisted of monitoring the concentrations of effluent versus time known as a breakthrough curve (BTC). We used NaCl and ZnCl$_2$ solutions with the concentration of 10 g/L as a tracer, and injected them respectively into the inlet boundary of the soil sample as a square pulse type, and monitored the effluent concentrations at the exit boundary under a steady state condition using an EC-meter and ICP-AES. The batch test was conducted based on the standard procedure of equilibrating fine fractions collected from the soil with various initial ZnCl$_2$ concentrations, and analysis of Zn ions in the equilibrated solutions using ICP-AES. The results of column test showed that i) the peak concentration of ZnCl$_2$analyzed by ICP was far less than that of either NaCl or bulk electrical conductivity and ⅱ) travel times of peak concentrations for two tracers were more less identical. The relatively low concentration of Zn can be explained by ion exchange between Zn and other cations, and possible precipitation of Zn in the form of Zn(OH)$_2$due to high pH range (7.0∼7.9) of the effluent. The identical result of travel times of peak concentrations indicates that the retardation effect is not present in the soil. The only way to describe the prominent decrease of Zn ion was to introduce decay or sink coefficient in the CDE model to account for irreversible decrease of Zn ions in the aqueous phase.

• Journal of Sericultural and Entomological Science
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• v.41 no.1
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• pp.36-40
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• 1999

The optimal condition for the production of the artificial fruiting bodies of Paecilomyces japonica in bulk was determined from the observation of the conidial, hyphal, and cultural condition and the medium. The colony was grown 32 mm diameter in 14 days on potato dextrose agar(PDA). Conidia was irregularly long oval-shaped and measured 4.07${\times}$1.56 ${\mu}$m in average. The hyaline hyphae formed transparent bundles which branched out. The fruiting body on the insect surface was measured 30 to 50 mm in length and formed up to 55 branches. Potato dextrose(PD) both was the most effective for the growth of Paecilomyces japonica among the liquid type media. About 3.1 mg mrcelia in dry weight were produced in 50 ml/PD broth. The best condition for the production of conidia under which condition 4.3${\times}$10$^8$ conidia/ml were harvested was pH 5.0 in acidity and 20$^{\circ}C$ following preculture at 24$^{\circ}C$ in temperature for 7 days.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.4
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• pp.398-422
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• 2017

Objectives: The major aim of this study is to construct the database of retrospective exposure assessment for crystalline silica through reviews of literatures in South Korea. Methods: Airborne concentrations of crystalline silica were collected using an academic information search engine, Research Information Service System(RISS), operated by the Korea Education & Research Information Service(KERIS). The key words used for the literature search were 'silica', 'crystalline silica', 'cristobalite', 'quartz' and 'tridymite'. A total number of 18 published documents with the information of crystalline silica level in air or bulk samples were selected and used to estimate retrospective exposures to crystalline silica. Weighted arithmetic mean(WAM) calculated across studies was summarized by industry type. Industries were classified according to Korea Standard Industrial Classification(KSIC) using information provided in the literature. Results: A total of 2,131 individual air sampling data measured from 1987 to 2012 were compiled. Compiled individual measurement data consisted of 827 respirable crystalline silica (RCS), 31 total crystalline silica(TCS), 24 crystalline silica(CS), 778 respirable dust(RD) and 471 total dust(TD). Most of RCS measurements(68.9%) were collected from 'cast of metals(KSIC 243)'. Comparing industry types, 'mining coal and lignite(KISC 051)' showed the highest WAM concentration of RCS, $0.14mg/m^3$, followed by $0.11mg/m^3$ of 'manufacture of other non-metallic mineral products(KSIC 239)', $0.108mg/m^3$ of 'manufacture of ceramic ware(KSIC 232)', $0.098mg/m^3$ of 'heavy construction(KSIC 412)' and $0.062mg/m^3$ of 'cast of metals(KSIC 243)'. In terms of crystalline silica contents in airborne dust, 'manufacture of other non-metallic mineral products(KSIC 239)' showed the highest value of 7.3%(wt/wt), followed by 6.8% of 'manufacture of ceramic ware(KSIC 232)', 5.8% of 'mining of iron ores(KSIC 061)', 4.9% of 'cast of metals(KSIC 243)' and 4.5% of 'heavy construction(KSIC 412)'. WAM concentrations of RCS had no consistent trends over time from 1994 ($0.26mg/m^3$) to 2012 ($0.12mg/m^3$). Conclusion: The data set related RCS exposure level by industries can be used to determine not only the possibility of retrospective exposure to RCS, but also to evaluate the level of quantitative retrospective exposure to RCS.

• Korean Journal of Materials Research
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• v.13 no.6
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• pp.347-351
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• 2003

II-Ⅵ ZnO compound semiconductor thin films were grown on $\alpha$-Al$_2$O$_3$(0001) single crystal substrate by radical beam assisted molecular beam epitaxy and the optical properties were investigated. Zn(6N) was evaporated using Knudsen cell and O radical was assisted at the partial pressure of 1$\times$10$^{4}$ Torr and radical beam source of 250-450 W RF power. In $\theta$-2$\theta$ x-ray diffraction analysis, ZnO thin film with 500 nm thickness showed only ZnO(0002)and ZnO(0004) peaks is believed to be well grown along c-axis orientation. Photoluminescence (PL) measurement using He-Cd ($\lambda$=325 nm) laser is obtained in the temperature range of 9 K-300 K. At 9 K and 300 K, only near band edge (NBE) is observed and the FWHM's of PL peak of the ZnO deposited at 450 RF power are 45 meV and 145 meV respectively. From no observation of any weak deep level peak even at room temperature PL, the ZnO grains are regarded to contain very low defect density and impurity to cause the deep-level defects. The peak position of free exciton showed slightly red-shift as temperature was increased, and from this result the binding energy of free exciton can be experimentally determined as much as $58\pm$0.5 meV, which is very closed to that of ZnO bulk. By van der Pauw 4-point probe measurement, the grown ZnO is proved to be n-type with the electron concentration($n_{e}$ ) $1.69$\times$10^{18}$$cm^3$, mobility($\mu$) $-12.3\textrm{cm}^2$/Vㆍs, and resistivity($\rho$) 0.30 $\Omega$$\cdot$cm.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1999.04a
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• pp.5-5
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• 1999

The Principal deficiency of the existing notion about the sintering-mixtures consists in the fact that almost no attention is focused on the Phenomenon of alloy formation during sintering, its connection with dimensional changes of powder bodies, and no correct ideas on the driving force for the sintering process in the stage of establishing chemical equilibrium in a system are available as well. Another disadvantage of the classical sintering theory is an erroneous conception on the dissolution mechanism of solid in liquid. The two-particle model widely used in the literature to describe the sintering phenomenon in solid state disregards the nature of the neighbouring surrounding particles, the presence of pores between them, and the rise of so called arch effect. In this presentation, new basic scientific principles of the driving forces for the sintering process of a two-component powder body, of a diffusion mechanism of the interaction between solid and liquid phases, of stresses and deformation arising in the diffusion zone have been developed. The major driving force for sintering the mixture from components capable of forming solid solutions and intermetallic compounds is attributed to the alloy formation rather than the reduction of the free surface area until the chemical equilibrium is achieved in a system. The lecture considers a multiparticle model of the mixed powder-body and the nature of its volume changes during solid-state and liquid-phase sintering. It explains the discovered S-and V-type concentration dependencies of the change in the compact volume during solid-state sintering. It is supposed in the literature that the dissolution of solid in liquid is realised due to the removal of atoms from the surface of the solid phase into the melt and then their diffusicn transfer from the solid-liquid interface into the bulk of liquid. It has been shown in our experimental studies that the mechanism of the interaction between two components, one of them being liquid, consist in diffusion of the solvent atoms from the liquid into the solid phase until the concentration of solid solutions or an intermetallic compound in the surface layer enables them to pass into the liquid by means of melting. The lecture discusses peculimities of liquid phase formation in systems with intermediate compounds and the role of the liquid phase in bringing about the exothermic effect. At the frist stage of liquid phase sintering the diffusion of atoms from the melt into the solid causes the powder body to grow. At the second stage the diminution of particles in size as a result of their dissolution in the liquid draws their centres closer to each other and makes the compact to shrink Analytical equations were derived to describe quantitatively the porosity and volume changes of compacts as a result of alloy formation during liquid phase sinteIing. Selection criteria for an additive, its concentration and the temperature regime of sintering to control the density the structure of sintered alloys are given.