• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.80-81
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• 2012

Recently, one of the critical issues in the etching processes of the nanoscale devices is to achieve ultra-high aspect ratio contact (UHARC) profile without anomalous behaviors such as sidewall bowing, and twisting profile. To achieve this goal, the fluorocarbon plasmas with major advantage of the sidewall passivation have been used commonly with numerous additives to obtain the ideal etch profiles. However, they still suffer from formidable challenges such as tight limits of sidewall bowing and controlling the randomly distorted features in nanoscale etching profile. Furthermore, the absence of the available plasma simulation tools has made it difficult to develop revolutionary technologies to overcome these process limitations, including novel plasma chemistries, and plasma sources. As an effort to address these issues, we performed a fluorocarbon surface kinetic modeling based on the experimental plasma diagnostic data for silicon dioxide etching process under inductively coupled C4F6/Ar/O2 plasmas. For this work, the SiO2 etch rates were investigated with bulk plasma diagnostics tools such as Langmuir probe, cutoff probe and Quadruple Mass Spectrometer (QMS). The surface chemistries of the etched samples were measured by X-ray Photoelectron Spectrometer. To measure plasma parameters, the self-cleaned RF Langmuir probe was used for polymer deposition environment on the probe tip and double-checked by the cutoff probe which was known to be a precise plasma diagnostic tool for the electron density measurement. In addition, neutral and ion fluxes from bulk plasma were monitored with appearance methods using QMS signal. Based on these experimental data, we proposed a phenomenological, and realistic two-layer surface reaction model of SiO2 etch process under the overlying polymer passivation layer, considering material balance of deposition and etching through steady-state fluorocarbon layer. The predicted surface reaction modeling results showed good agreement with the experimental data. With the above studies of plasma surface reaction, we have developed a 3D topography simulator using the multi-layer level set algorithm and new memory saving technique, which is suitable in 3D UHARC etch simulation. Ballistic transports of neutral and ion species inside feature profile was considered by deterministic and Monte Carlo methods, respectively. In case of ultra-high aspect ratio contact hole etching, it is already well-known that the huge computational burden is required for realistic consideration of these ballistic transports. To address this issue, the related computational codes were efficiently parallelized for GPU (Graphic Processing Unit) computing, so that the total computation time could be improved more than few hundred times compared to the serial version. Finally, the 3D topography simulator was integrated with ballistic transport module and etch reaction model. Realistic etch-profile simulations with consideration of the sidewall polymer passivation layer were demonstrated.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1727-1734
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• 2005

The fermentation characteristics and mono- and di-saccharides compositions during the early stage of ensiling were studied with a temperate grass, Italian ryegrass (Lolium multiflorum Lam.) and a tropical grass, guineagrass (Panicum maximum Jacq.). The laboratory silos were kept in the room set at 25$^{\circ}C$, and then were opened on 0.5, 1, 2, 3, 5 and 7 days (14 days in Italian ryegrass) after ensiling, respectively. The Italian ryegrass silage showed a fast and large pH decrease caused by a fast and large production of lactic acid during the first 5 days of ensiling and succeeded to achieve lactic acid type fermentation; high lactic acid/acetic acid and lactic acid content at the end of ensiling (14 days), low values of pH (3.74), acetic acid, ethanol and ammonia-N/total nitrogen, none or only small amounts of Butyric acid, valeric acid and propionic acid. The guineagrass silage showed a slow decrease in pH and a slow increase in lactic acid content during the full ensiling period, causing a high final pH value, low contents of lactic acid, acetic acid, total volatile fatty acids and total organic acids. In Italian ryegrass silage, mono- and di-saccharides compositions decreased largely within the initial 0.5 day (12 h) of ensiling. Sucrose disappeared rapidly within the initial 0.5 day of ensiling, but fructose and glucose contents showed an initial rise by the activity of enzymes in plant tissues, and then decreased gradually. On the other hand, the contents of monoand di-saccharides in guineagrass showed the largest decreases due mainly to plant respiration within the initial 0.5 day of ensiling, and no initial rises in fructose and glucose contents during the early stage of ensiling because of the absence of fructans which are hydrolyzed into fructose and glucose in temperate grasses. In both silages, the rate of reduction in mono- and di-saccharides compositions within the initial 5 days of ensiling was ranked in the order of glucose>fructose>sucrose, suggesting that glucose and fructose might be more favorably utilized than sucrose by microorganisms and glucose is the first fermentation substrate. It was concluded that the silage made from Italian ryegrass with high moisture content had a good fermentation quality owing to the dominance of lactic acid bacteria and active lactic acid fermentation during the initial stage of ensiling. These results can be explained by rapid plant sap liberation and the high activity of plant enzyme hydrolyzed fructans into fructose and glucose within the initial 2 days of ensiling, which stimulate the homofermentative lactic acid bacteria growth. In ensiling a temperate grass, the physical characteristics may ensure the rapid onset of fermentation phase, which results from the smaller losses of water-soluble carbohydrates during the initial stage of ensiling and providing sufficient water-soluble carbohydrates for lactic acid bacteria. The silage made from guineagrass with intermediate dry matter and high initial mono- and di-saccharides content was stable silage. This could be explained by the higher incorporation of air during the very early stage of ensiling and the restriction of cell breakdown and juice release due to the properties of a tropical grass with coarse porosity and stemmy structures. These physical characteristics delayed the onset of lactic acid bacteria fermentation phase by extending the phases of respiration and aerobic microorganisms activity, causing the higher loss of water-soluble carbohydrates and the shortage of lactic acid bacteria fermentation substrates.

• Journal of the Mineralogical Society of Korea
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• v.28 no.1
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• pp.39-49
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• 2015

Recently, carbon capture and storage (CCS) techniques have been globally studied. This study was conducted to use waste cement powder as an efficient raw material of mineral carbonation for $CO_2$ sequestration. Direct aqueous carbonation experiment was conducted with injecting pure $CO_2$ gas (99.9%) to a reactor containing $200m{\ell}$ reacting solution and the pulverized cement paste (W:C = 6:4) having particle size less than 0.15 mm. The effects of two additives (NaCl, $MgCl_2$) in carbonation were analyzed. The characteristics of carbonate minerals and carbonation process according to the type of additives and pH change were carefully evaluated. pH of reacting solution was gradually decreased with injecting $CO_2$ gas. $Ca^{2+}$ ion concentration in $MgCl_2$ containing solution was continuously decreased. In none $MgCl_2$ solution, however, $Ca^{2+}$ ion concentration was increased again as pH decreased. This is probably due to the dissolution of newly formed carbonate mineral in low pH solution. XRD analysis indicates that calcite is dominant carbonate mineral in none $MgCl_2$ solution whereas aragonite is dominant in $MgCl_2$ containing solution. Unstable vaterite formed in early stage of experiment was transformed to well crystallized calcite with decreasing pH in the absence of $MgCl_2$ additives. In the presence of $MgCl_2$ additives, the content of aragonite was increased with decreasing pH whereas the content of calite was decreased.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.166-172
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• 2018

This study set out to conduct a field survey with smart greenhouse-based farms in seven types to figure out the actual state of smart greenhouses distributed across the nation before selecting a system to implement an optimal greenhouse environment and doing a research on higher productivity based on data related to crop growth, development, and environment. The findings show that the farms were close to an intelligent or advanced smart farm, given the main purposes of leading cases across the smart farm types found in the field. As for the age of farmers, those who were in their forties and sixties accounted for the biggest percentage, but those who were in their fifties or younger ran 21 farms that accounted for approximately 70.0%. The biggest number of farmers had a cultivation career of ten years or less. As for the greenhouse type, the 1-2W type accounted for 50.0%, and the multispan type accounted for 80.0% at 24 farms. As for crops they cultivated, only three farms cultivated flowers with the remaining farms growing only fruit vegetables, of which the tomato and paprika accounted for approximately 63.6%. As for control systems, approximately 77.4% (24 farms) used a domestic control system. As for the control method of a control system, three farms regulated temperature and humidity only with a control panel with the remaining farms adopting a digital control method to combine a panel with a computer. There were total nine environmental factors to measure and control including temperature. While all the surveyed farms measured temperature, the number of farms installing a ventilation or air flow fan or measuring the concentration of carbon dioxide was relatively small. As for a heating system, 46.7% of the farms used an electric boiler. In addition, hot water boilers, heat pumps, and lamp oil boilers were used. As for investment into a control system, there was a difference in the investment scale among the farms from 10 million won to 100 million won. As for difficulties with greenhouse management, the farmers complained about difficulties with using a smart phone and digital control system due to their old age and the utter absence of education and materials about smart greenhouse management. Those difficulties were followed by high fees paid to a consultant and system malfunction in the order.

• KDI Journal of Economic Policy
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• v.12 no.3
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• pp.153-172
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• 1990

The present paper investigates the potential value of strategic antitrust policy in an oligopolistic international market. The market is characterized by a non-cooperative Cournot-Nash equilibrium and by asymmetry in costs among firms in the world market. The model is useful for two reasons. First, it is important in the context of policy-making to examine the conditions under which it may be beneficial to relax antitrust law to enhance competitiveness. Second, the explicit derivation of the level of cost-saving required for a gain in total domestic surplus provides an empirical rule for excluding industries that do not satisfy the requirements for a socially beneficial antitrust exemption. Results of the analysis include a criterion that tells how the cost-saving and concentration effects of a merger offset each other. The criterion is derived from fairly general assumptions on demand functions and is simple enough to be applied as a part of the merger guidelines. Another interesting policy implication of our analysis is that promoting mergers would not be a beneficial strategy in a net importing industry where cost-saving opportunities are thin. Cost-saving domestic mergers are more likely to increase national welfare in exporting industries. The best candidate industries for application of strategic antitrust policy are those with the following characteristics: (i) a large potential for efficiency enhancement; (ii) high market concentration at the world but not the domestic level; (iii) a high ratio of exports to imports. Recently, many policymakers and economists in Korea have also come to believe that the appropriate antitrust policy in an era of increased foreign competition may actually be to encourage rather than to prohibit domestic mergers. The Industry Development Act of 1986 and the proposed bill for Mergers and Conversions in the Financial Industry of 1990 reflect this changing perspective on antitrust policy. Antitrust laws may burden domestic firms in the sense that they have a more constrained strategy set. Expenditures to avoid antitrust attacks could also increase costs for domestic firms. But there is no clear evidence that the impact of antitrust policy is significant enough to harm the competitiveness of domestic firms. As a matter of fact, it is necessary for domestic financial institutions to become large in scale in this era of globalization. However, the absence of empirical evidence for efficiency enhancement from mergers suggests caution in the relaxation of antitrust standards.

• Journal of Korean Academy of Nursing
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• v.10 no.1
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• pp.41-55
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• 1980

The medical care insurance system, being put into practice nearly for three years, seem to have brought about some considerable problems as serious for the government as to consider a revision of that system. As one of the most serious problems of present system, the treatment cost of insurance patients is so remarkably low in comparison with than of non-insurance cases that normal operation of hospitals is threatened and care services of low quality are induced. The researcher carried out this survey to analyze and bring to light several aspects of treatment cost of non-insurance patients as a material for a re-assessment of the cost of insurance cases which shows a a considerable difference in amount at the standpoint of hospitals with than of non-insurance cases and further, hoping the significant blind spot of present insurance system(that is, the absence of regulations' for cost assessment by patterns or types of health care treatment) will be mended in near future. The survey was carried out with the treatment invoice sheets of total 902 in-hospital Patients of a general hospital in Seoul during the period of the 2 nd quarter of the year(1979). Among total 902 patients, 694 cases were used for analysis, because those disease or syndromes shared by less than 10% of the patients were put aside before procession. The data were analyzed by kinds or types of diseases, demographic characteristics of patients, hospitalization patterns, types of nursing treatment, etc. The result of analysis was as follows 1. Among all the non-insurance cases, those who received one or more kinds of nursing treatment mounted up to 96. 7 ％. The invoice issue frequency per person was 7.2 times, while that frequency per day for a person was 0.8, : the treatment cosr per person was ￦22,650 while its daily average was ￦2,430, due to the average 9.3 in-hospital days per person. 2. As to the nursing treatment types by the demographic characteristics of patients and hospitalization patterns. a. The unit cost female patients was generally more expensive them that of males, and independent nursing service was more given than other types of treatment. As to age, higher age groups received independent nursing service most, while the youngest group received instrumental and integrated nursing services. b. As to room grade, the unit cost of I.C.U. cases was the highest : and the cast of private room patients was higher than that of public room patients. By in-hospital days, the curve of function showed L. type : that is, the longer stay, the lower function. 3. State of treatment types by kinds of disease were ; a. Dependent nursing service showed comparatively high availability in surgical and neurologic disease and independent nursing service was most received by medical, obstetrical and urological patients, while instrumental and integrated services were most available for respiratory disease and obstetrical and neurologic diseases next. b. The invoice issue frequency per day for a patient was highest in obstetrical disease 3.8 times, and the unit cost(per one invoice sheet) was also highest in obstertrical disease(￦10,880) and next in neurologic cases(￦ 4,690 ). 4. As to the pertained departments. a. Cost amount per person was highest in department of Psychiatries daily cost was highest in obstetrical cases : while the invoice issue frequency was highest in obstetrics and next in pediatrics. b. In departments in need of surgical operation, dependent nursing care was highly availabl : while in internal medicine and obstetrics, independent service was higher. Psychiatrics showed the highest the of integrate nursing while pediatrics and obstetrics higher of instrumental services. The variation co-efficien of treatment cost came out to be relatively in high in special surgery, opthalmology and internal medicine. 5. State of treatment cost by types of nursing behavior was. a. The average frequency of invoice issue was 3.5 (times). Among the type four types of treatment, instrumetal service (4.3) and independent nursing behavior(3.9) showed higher frequency than average respectively. But as to unit cost (per invoice). dependent (￦5,200) and integrated (￦5,340) nursing care services were higher than average and considerably higher than the other two types. b. In repect patient distribution. independent nursing behavior(80.3% ) was the highest and depend ent nursing (31.7% ) the lowest. The variation co-efficient of treatment cost appeared highest in dependent nursing be havior as a whole, and among that, doctor's diagnosis showed the highest coefficient value (100.7). In conclusion, the variaty of treatment cost(treatment itself ) by various characteristics and treatment types pro- that treatment various sort of patients and treatment cost of various types of nursing behavior cannot be uniform. Therefore, to attain the equalization of health care service and its cost both for insurant and non-insurant patients, a more specific provision for assessment of cost should be added to the present medical care insurance system and, in addition, the cost of nursing treatment is desired to be inserted into the treatment invoice.

• Journal of Korean Academy of Nursing Administration
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• v.5 no.3
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• pp.477-500
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• 1999

Korean labor market has showed remarkable change of the increase in the amount of unemployment and contingent employment since IMF bailout agreement. There is a theoretical position to explain this increase in contingent employment at hospitals with the notion of flexibility. The high flexibility of employment due to the increase of contingent employees is becoming very important part in new business strategy of hospitals. The types of contingent employment of the nurse are part-time employment temporary employment, fixed-term employment, and internship which was introduced in early 1999. Recently, Korean health care industry managers have paid attention to the customer oriented service, rationalization of business administration, service quality control so that they can adjust their business to outer environment. Especially their efforts concentrate on the wage reduction through efficient and scientific control of man power because wage shares about 40% of total cost. This dissertation aims at verifying the phenomena of the contingent employment of the nurse and analyzing the related factors and problems. To rephrase these aims in ordinal: First, verifying the phenomena of contingent employment of the nurse. Second, verifying the problems of that phenomena. Third, analyzing the related factors of the contingent employment of the nurse. To accomplish these research goals, a statistical survey was executed. in which 384 questionnaires-66 for manager nurses, 318 for contingent nurses - were given to nurses working at 66 hospitals-which have at least 100 beds-in Seoul. Among them, 187 questionnaires-38 from manager nurses, 149 from contingent nurses'- 'were returned. Then, the data coded and submitted to T-test, $X^2$ -test, variance analysis(ANOVA), correlation analysis, multiple regression analysis, Logistic Regression with SAS program. The research results of the contingent nurses are followings: 1. The average career term at the present hospital 8.4 months: duty-on days per month are 24.2 days: working time per day is 7.9 hours. These results showed little difference from regular nurses. 2. Their wage level is about 70% of regular nurses except for internship nurses whose wage level is 41% of regular nurses. To break down the wage composition, part-time nurses and internship nurses get few allowance and bonus. And contingent nurses get very low level of additional pay except for fixed-term nurses who are under similar condition of employment to regular nurses. These results show that hospital managers are trying to reduce the labor cost not only through the direct way of wage reduction but through differential treatment of bonus, retirement allowance, and other additional pay. 3. The problem of contingent employment: low level of pay; high level of turn-over rate: weakening of union; low level of working condition: heavy burden of work; inhuman treatment. The contingent nurses consider these problems more seriously than manager nurses do. What manager nurses regard problematic is the absence of feeling-belonged and responsibility of the contingent nurses. 4. The factors strongly related with the rate of the number of contingent nurses for the number of regular nurses; gross turn-over nurses; average in-patients per day; staring wage of graduate from professional college: the type of hospital ownership; the number of beds; the gap between gross newcomer nurses and gross turn-over nurses. The factors related with their gross wage per month; the number of beds; applying of health insurance; applying of industrial casualty insurance; applying of yearly-paid leave; the type of hospital ownership; average out-patients per day; gross turn-over nurses. The meaningful factors which make difference by employment type: monthly-paid leave; physiological leave. The logistic regression analysis using these two factors shows that monthly-paid leave is related with the type of hospital ownership; the number of beds; average out-patient per day, and physiological leave is related with the gross newcomer nurses; gross turn-over nurses; the number of beds.

• Microbiology and Biotechnology Letters
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• v.37 no.2
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• pp.118-124
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• 2009

Esterase EM2L8 gene isolated from deep sea sediment was expressed in Escherichia coli BL21 (DE3) and the esterase activity of the cell-free extract was assayed using p-nitrophenyl butyrate-spectrophotometric method. Its optimum temperature was $40-45^{\circ}C$ and 45% activity of the maximum activity was retained at $15^{\circ}C$. The activation energy at $15-45^{\circ}C$ was calculated to be 4.9 kcal/mol showing that esterase EM2L8 was a typical cold-adapted enzyme. Enzyme activity was maintained for 6 h and 4 weeks at $30^{\circ}C$ and $4^{\circ}C$, respectively. When each ethanol, methanol, and acetone was added to the reaction mixture to 15% concentration, enzyme activity was maintained. In the case of DMSO, enzyme activity was kept up to 40% concentration. (S)-4-Chloro-3-hydroxy butyric acid is a chiral intermediate for the synthesis of Atorvastatin, a hyperlipemia drug. When esterase EM2L8 (40 U) was added to buffer solution (1.2 mL, pH 9.0) containing ethyl-(R,S)-4-chloro-3-hydroxybutyrate (38 mM), it was hydrolyzed into 4-chloro-3-hydroxy butyric acid with a rate of $6.8\;{\mu}mole/h$. The enzyme hydrolyzed (S)-substrate more rapidly than (R)-substrate. When conversion yield was 80%, e.e.s value was 40%. When DMSO was added, hydrolysis rate increased to $10.4\;{\mu}mole/h$. The plots of conversion yield vs e.e.s in the presence or absence of DMSO were almost same, implying that the reaction enantioselectivity was not changed by the addition of DMSO. Taken together, esterase EM2L8 had high activity and stability at low temperatures as well as in various organic solvents/aqueous solutions. These properties suggested that it could be used as a biocatalyst in the synthesis of useful pharmaceuticals.

• Toxicological Research
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• v.4 no.1
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• pp.55-84
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• 1988

This study was carried out to investigate the teratological potential of azinphos-methyl in the rat fetuses and to establish the nature of the effects on organogenesis and intrauterine development. The Sprague-Dawley female rats (180-210g) without previous litter were used in this study. Azinphos-methyl dosages of 0.094mg/kg, 0.4mg/kg, 1.5mg/kg were selected based on the acute intragastric $LD_{50}$ of 15mg/kg in the rat. Azinphos-methyl in water (Treatment Group), non-treatment control (Negative Control), water control (Sham Control), were administered by oral route and aqueous solution of acetyl salicylic acid (Positive Control) was administered by gavage at rate of 10 ml/kg of body weight from day 6 through 15. The results obtained were summarized as follows. 1. Decreased body weight of dams was observed in animals treated with aspirin and azinphos-methyl 1.5 mg/kg from day 7 through 14. (P<0.01) 2. There was an apparent decrement in the absolute liver weight in the azinphos-methyl 1.5 mg/kg treated group (P<0.05). However, the absolute and relative kidney weight in aspirin group (P<0.05, P<0.01) and the absolute and relative ovary weight in aspirin, azinphos-methyl treatment groups (P<0.01, P<0.05) were increased. 3. Decreased protein contents of dam's liver was observed in the aspirin and high dose azinphos-methyl treated group of animals (P<0.01). 4. The number of male-female ratio per dam increased in azinphos-methyl 1.5 mg/kg group but there was an apparent decrement in the body weight of fetuses in aspirin and high dose azinphos-methyl group (P<0.01, P<0.05). Total immature and resorbed fetuses were increased in aspirin group and the number of dead fetuses were also increased in azinphos-methyl 1.5mg/kg treated group of animals. (P<0.01, P<0.05). 5. In soft tissue defects, diaphragmatic hernia in diaphragm, anophthalmia, enlarged olfactory bulb, hydrocephalus, absence of third and lateral ventricle in skull, hydronephrosis in kidney, atrophy of left ventricle wall, enlarged apex in heart were observed. Especially, defects of diaphragm, heart and eye ball showed peak incidences in the high dose azinphosmethyl and aspirin group. (P<0.01). 6. Variations in the ossification patterns of skull, sternebrae, tail, forelimbs and hindlimbs showed peak incidences in the aspirin and high dose azinphos-methyl group. (P<0.01). 7. In the developmental indices of offspring, the mortality of aspirin and azinphos-methyl 1.5mg/kg treated group was higher than that of negative control. And, there was an apparent decrement in the body weight of fetuses (P<0.01) and considerable differences were obtained in pivoting, development of fur, auditory function, vision, quadrupled muscle development and testes descent in aspirin and azinphos-methyl 1.5mg/kg group. (P<0.01).

• The Korean Journal of Pharmacology
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• v.26 no.2
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• pp.167-176
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• 1990

In the present study, we examined the effects of tamoxifen and LY117018 on various parameters for the estrogenic actions in order to understand the mechanism by which tamoxifen and LY117018 act on the uterine cells in 21-23 day old immature rats. Tamoxifen and LY117018 stimulated uterine weight and uterine contents of DNA, protein, and peroxidase activity in the absence of estradiol while inhibited above parameters in the presence of estradiol. Both cytosolic and nuclear progesterone receptors were increased by the treatment of tamoxifen and LY117018 as well as estradiol, but estradiol-induced increase in the progesterone receptors were reduced by the treatment of antiestrogens. These effects were enhanced by the multiple injections of antiestrogens. It seemed that tamoxifen was more agonistic than LY117018 but less antagonistic than LY117018, judged by their effects on various parameters for the estrogenic action. The affinities of estradiol, tamoxifen, and LY117018 for the estrogen receptor were $0.17{\pm}0.01nM(100%)$, $1.10{\pm}0.01nM(6.3%)$, and $0.23{\pm}0.01nM(77%)$, respectively. Furthermore, LY117018 was the competitive ligand for the estrogen receptor in dose-related manner but tamoxifen was not. Following estradiol treatment, nuclear estrogen receptor was sharply increased by 1 h, reaching the maximum by 16 h, while tamoxifen and LY117018 slightly increased nuclear estrogen receptor by 1 h and then decreased thereafter. It is therefore concluded that LY117018 is a competitive antagonist for the estrogen receptor with less estrogenic activity, compared to tamoxifen with low affinity to the estrogen receptor, and tamoxifen may act through other binding site than the estrogen receptor.