• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.210-210
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• 2011

The effects of CH2F2 and N2 gas flow rates on the etch selectivity of silicon nitride (Si3N4) layers to extreme ultra-violet (EUV) resist and the variation of the line edge roughness (LER) of the EUV resist and Si3N4 pattern were investigated during etching of a Si3N4/EUV resist structure in dual-frequency superimposed CH2F2/N2/Ar capacitive coupled plasmas (DFS-CCP). The flow rates of CH2F2 and N2 gases played a critical role in determining the process window for ultra-high etch selectivity of Si3N4/EUV resist due to disproportionate changes in the degree of polymerization on the Si3N4 and EUV resist surfaces. Increasing the CH2F2 flow rate resulted in a smaller steady state CHxFy thickness on the Si3N4 and, in turn, enhanced the Si3N4 etch rate due to enhanced SiF4 formation, while a CHxFy layer was deposited on the EUV resist surface protecting the resist under certain N2 flow conditions. The LER values of the etched resist tended to increase at higher CH2F2 flow rates compared to the lower CH2F2 flow rates that resulted from the increased degree of polymerization.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.472-472
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• 2011

The capacitive coupled plasma (CCP) has been extensively used in the semiconductor industry because it has not only good uniformity, but also low electron temperature. But CCP source has some problems, such as difficulty in varying the ion bombardment energy separately, low plasma density, and high processing pressure, etc. In this reason, dual frequency CCP has been investigated with a separate substrate biasing to control the plasma parameters and to obtain high etch rate with high etch selectivity. Especially, in this study, we studied on the etching of $SiO_2$ by using the pulse-time modulation in the dual-frequency CCP source composed of 60 MHz/ 2 MHz rf power. By using the combination of high /low rf powers, the differences in the gas dissociation, plasma density, and etch characteristics were investigated. Also, as the size of the semiconductor device is decreased to nano-scale, the etching of contact hole which has nano-scale higher aspect ratio is required. For the nano-scale contact hole etching by using continuous plasma, several etch problems such as bowing, sidewall taper, twist, mask faceting, erosion, distortions etc. occurs. To resolve these problems, etching in low process pressure, more sidewall passivation by using fluorocarbon-based plasma with high carbon ratio, low temperature processing, charge effect breaking, power modulation are needed. Therefore, in this study, to resolve these problems, we used the pulse-time modulated dual-frequency CCP system. Pulse plasma is generated by periodical turning the RF power On and Off state. We measured the etch rate, etch selectivity and etch profile by using a step profilometer and SEM. Also the X-ray photoelectron spectroscopic analysis on the surfaces etched by different duty ratio conditions correlate with the results above.

• Journal of The Korean Dental Society of Anesthesiology
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• v.3 no.1 s.4
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• pp.28-33
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• 2003

Background: The fundamental responsibility of an anesthesiologist is to maintain adequate gas exchange. Failure to maintain a patent airway can result in brain damage or death. Generally, in patients with mandibular prognathism, who have the protruded mandible, the mask ventilation was thought to be not easy. The purpose of this study was to observe the degree of the difficulty of airway management in mandibular prognathism using some anatomic criteria for defining and grading difficulty of airway and difficulty of endotracheal intubation with direct laryngoscope. Methods: The observations and measurements are done to the 54 patients with mandibular prognathism, who were scheduled for corrective esthetic surgery. The case study is done to the 30 patients with normal mandible for control group. In all patients, mouth opening distance (MOD), mouse opening angle (MOA), mandibular length (ML), mandibular depth (MD), thyromental distance (TMD), thyromental area (TMA), Mallampati grades, and Cormack and Lehane grades are measured. T-test and Chi-square test are done (P < 0.05). Results: In the mandibular prognathism cases, the measurements of MD, TMD and TMA are more greater than those of controls (P < 0.05). Mallampati grades with tongue thrust are higher in the female mandibular prognathism cases than those of female controls. Most of the grades of the mandibular prognathism cases with Cormack and Lehane grading system are I or II being easy intubation cases (P < 0.05) Conclusions: In the patients of mandibular prognathism, the intubation with laryngoscope will be easer than that of normal mandible in general. It is for that their laryngeal aperture can be easily visible when the laryngoscope are used.

• The Journal of the Korea Contents Association
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• v.17 no.3
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• pp.359-369
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• 2017

The purpose of this study was to examine whether the effect of feedback would mask the performance differences that would result from different incentive pay distribution. Five critical service behaviors were identified and measured daily at a gas station located in Seoul. Participants were 5 employees working at the gas station. Independent variables were the types of incentive distribution and feedback. After baseline (A), equally-distributed group incentive condition (B) was introduced, and individual incentive condition (C) was introduced in the next phase. Then, after the withdrawal condition (A'), equally-distributed group incentive with feedback condition (B') was introduced and finally, the individual incentive with feedback condition (C') was introduced. The results suggested that all employees showed higher work performance under individual incentive than equally-distributed group incentive system when feedback were not delivered. However, there was no difference in work performance between two incentive conditions in the phases in which feedback were delivered. These findings suggest that feedback can reduce performance differences between equally-distributed group incentives and individual incentives.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.124-131
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• 2003

The concentration of nitrous oxide in dental environment has increased especially in pediatric department. In pediatric department frequently met the behavior disordered patients who need the deep sedation. As the deeply sedated patients could not respond well to verbal command, the amount of mouth breathing would be increased especially with mouth prop which backward transposition of mandible. Inhalation of low concentration of nitrous oxide for a long duration has caused various side effects such as spontaneous abortion and inhibition of methionine synthetase activity which is harmful to DNA synthesis. For evaluation of factors of mouth breathing during deep sedation. The author measured the concentration of nitrous oxide in breathing zone by the change of the scavenging methods. One is drain the gas through the tail part of reservoir bag of Jackson Ree's system naturally. Another is scavenge from tail portion of reservoir bag with negative pressure. Last one is scavenge from nasal mask with negative pressure. The nitrous oxide concentration in breathing zone was the lowest in nasal part drainage but high above the recommended concentration of NIOSH. The order of nitrous concentration in breathing zone was: natural drainage, tail part with negative pressure, nasal part with negative pressure. This would reflect the order of resistance of nasal airway and showed the amount of mouth breathing. From the above experiment, the resistance of nasal airway by the increment of gas flow in corrugating tube and reservoir bag would be one of the causative factors of mouth breathing in deeply sedated patients.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.12
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• pp.1755-1760
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• 2006

Studies were carried out at the National Institute of Animal Nutrition and Physiology, India to determine the effect of feeding chopped paddy straw (Oryza sativa) on the energy expenditure in crossbred cattle. Four crossbred cattle male, aged 5-6 years and weighing about 450 kg were used for this study. Three experimental trials, one each for the feeding of un-chopped paddy straw offered ad libitum (UCA), chopped paddy straw fed at restricted level (CR) and chopped paddy straw offered ad libitum (CA) were conducted. The quantity of un-chopped paddy straw consumed during UCA was assumed as the voluntary intake by the cattle and the same quantity was offered after chopping during CR. Each trial comprised of 21 d preliminary feeding period and 5 d of observation recording period. Expired gas was collected in Douglas bags using a face-mask and three-way valve at 6 hourly intervals i.e., at 09.30, 15.30, 21.30, and 03.30 h throughout the observation period. Expired gas and ambient air inspired by the animals were analyzed for the oxygen content through paramagnetic oxygen analyzer. Energy expenditure (EE) by the animals was calculated by determining the volume of oxygen consumed per minute (STP) and multiplying by 4.825. Paddy straw used in all the three trials contained (g/kg DM) 90.0 CP, 786 OM, 700 NDF, 489 ADF, 357 Cellulose and 60.0 ADL. Metabolizable energy (ME) was 6.9 MJ/kg DM. Dry matter intake (DMI) both in UCA and CR was about 6.8 kg, except that it was chopped in CR. Chopping has resulted in 32% improvement (9 kg) in DMI of CA as compared to that of UCA. Although ME intake was similar in UCA and CR (47.2 MJ/day), energy expenditure (EE) was higher in UCA (23.3 MJ) when compared to that of CR (19.5 MJ). The ME intake (63.3 MJ) as well as EE (27.1 MJ) was highest in CA. Energy expenditure when expressed as MJ/kg DMI was 3.48, 2.90 and 3.12; whereas as per cent of ME intake it was 50, 41 and 44 in UCA, CR and CA respectively. Our study has unequivocally confirmed that chopping of poor quality roughages like paddy straw has definite advantages not only in terms of improving the intake by decreasing the time taken for ingestion but also in reducing the energy cost of eating.

• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.4
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• pp.508-513
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• 2018

Tidal volume by sevoflurane in small amounts is stable due to the increase in the breathing rate. But alveolus ventilation decreases due to sevoflurane as the degree of sedation increases; this ultimately causes $PaCO_2$ to rise. The occurrence of suppression of breath increases the risk of severe hypoxia and hypercapnia in deeply sedated patients with disabilities. Sevoflurane inhalation anesthesia has a number of risks and may have unexpected problems with hemodynamic changes depending on the underlying state of the body. This study was conducted to examine the stability of internal acid-base system caused by respiratory depression occurring when patients with disabilities are induced by sevoflurane. Anesthetic induction was carried out by placing a mask on top of the patient's face and through voluntary breathing with 4 vol% of sevoflurane, 4 L/min of nitrous oxide, and 4 L/min of oxygen. After the patient's loss of consciousness and muscle relaxation, IV line was inserted by an expert and intravenous blood gas was analyzed by extracting blood from vein. In a deeply sedated state, the average amount of pH of the entire patients was measured as $7.36{\pm}0.06$. The average amount of $PvCO_2$ of the entire patients was measured as $48.8{\pm}8.50mmHg$. The average amount of $HCO_3{^-}$ of the entire patients was measured as $27.2{\pm}3.0mmol/L$. In conclusion, in dental treatment of patients with disabilities, the internal acid base response to inhalation sedation using sevoflurane is relatively stable.

• Journal of agricultural medicine and community health
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• v.48 no.4
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• pp.239-250
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• 2023

Objective: This study was a preliminary study for the prevention programs for farmers' occupational diseases. It selected the priorities recognized by farmers, such as occupational diseases, and also identifies the effectiveness and feasibility of prevention programs among diseases recognized by farmers. Therefore, we plan to use it as basis data for future farmer safety and health programs. Method: The subjects of the study were farmers living in the region, selected through a snowball recruitment method, and a total of 671 people were targeted. The priority selection method was the Basic Priority Rating System (BPRS) method, and among the occupational diseases, programs to prevent musculoskeletal diseases, cardiovascular and respiratory diseases, and pesticide poisoning were surveyed on the effectiveness and feasibility of farmers. Results: Among occupational diseases, the highest priority was musculo-skeletal disease, followed by respiratory disease and pesticide poisoning. Among the programs for musculoskeletal disease, 'use of agricultural work convenience equipment and auxiliary tools' had the highest perceived effectiveness and feasibility. Among the five programs for pesticide poisoning, 'equipment of protective equipment such as pesticide protective clothing/glove' had the highest effectiveness at 67.4%, and 'compliance with pesticide use instructions' had the highest level of feasibility at 64.3%. Among the four programs to prevent respiratory diseases, 'wearing a dust mask or gas mask' was the highest at 65.5% in terms of both effectiveness and feasibility. Conclusion: When carrying out safety and health programs for farmers, the priorities recognized by farmers should be taken into consideration, and the program contents should also be developed taking into account the size of effect and feasibility recognized by farmers.

• Tuberculosis and Respiratory Diseases
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• v.43 no.2
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• pp.190-200
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• 1996

Background : Mechanical ventilation constitutes the last therapeutic method for acute respiratory failure when oxygen therapy and medical treatment fail to improve the respiratory status of the patient. This invasive ventilation, classically administered by endotracheal intubation or by tracheostomy, is associated with significant mortality and morbidity. Consequently, any less invasive method able to avoid the use of endotracheal ventilation would appear to be useful in high risk patient. Over recent years, the efficacy of nasal mask ventilation has been demonstrated in the treatment of chronic restrictive respiratory failure, particularly in patients with neuromuscular diseases. More recently, this method has been successfully used in the treatment of acute respiratory failure due to parenchymal disease. Method : We assessed the efficacy of Bilevel positive airway pressure(BiPAP) in the treatment of acute exacerbation of chronic obstructive pulmonary disease(COPD). This study prospectively evaluated the clinical effectiveness of a treatment schedule with positive pressure ventilation via nasal mask(Respironics BiPAP device) in 22 patients with acute exacerbations of COPD. Eleven patients with acute exacerbations of COPD were treated with nasal pressure support ventilation delivered via a nasal ventilatory support system plus standard treatment for 3 consecutive days. An additional 11 control patients were treated only with standard treatment. The standard treatment consisted of medical and oxygen therapy. The nasal BiPAP was delivered by a pressure support ventilator in spontaneous timed mode and at an inspiratory positive airway pressure $6-8cmH_2O$ and an expiratory positive airway pressure $3-4cmH_2O$. Patients were evaluated with physical examination(respiratory rate), modified Borg scale and arterial blood gas before and after the acute therapeutic intervention. Results : Pretreatment and after 3 days of treatment, mean $PaO_2$ was 56.3mmHg and 79.1mmHg (p<0.05) in BiPAP group and 56.9mmHg and 70.2mmHg (p<0.05) in conventional treatment (CT) group and $PaCO_2$ was 63.9mmHg and 56.9mmHg (p<0.05) in BiPAP group and 53mmHg and 52.8mmHg in CT group respectively. pH was 7.36 and 7.41 (p<0.05) in BiPAP group and 7.37 and 7.38 in cr group respectively. Pretreatment and after treatment, mean respiratory rate was 28 and 23 beats/min in BiPAP group and 25 and 20 beats/min in CT group respectively. Borg scale was 7.6 and 4.7 in BiPAP group and 6.4 and 3.8 in CT group respectively. There were significant differences between the two groups in changes of mean $PaO_2$, $PaCO_2$ and pH respectively. Conclusion: We conclude that short-term nasal pressure-support ventilation delivered via nasal BiPAP in the treatment of acute exacerbation of COPD, is an efficient mode of assisted ventilation for improving blood gas values and dyspnea sensation and may reduce the need for endotracheal intubation with mechanical ventilation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.4
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• pp.446-452
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• 2014

Objective: This study aimed to evaluate the exposure status of formaldehyde(FA) among the nurses in ambulatory care departments of university hospital. Methods: Two university hospitals were surveyed. The FA concentration in air were measured to target 62 nurses in 8 ambulatory care departments(89 samples). Air sampling and analysis of FA were carried out according to the OSHA Method ID-205. The survey was conducted with questionnaire asking about how to control FA and whether the nurses use the formaldehyde protectors or not. Results: FA was detected in all samples. The maximum concentration of FA was 0.258 ppm and the geometric mean was 0.023 ppm. There was no sample that exceeded any of exposure standards by OSHA-TWA whereas there were 54 samples(60.7%) that exceeded the standards by NOISH-TWA. Among 62 nurses handling FA, 13 nurses(21.0%) used the protective gloves while nobody used a gas mask. It was assessed that any of 8 common ambulatory care departments did not use a safety cabinet for FA in which local exhaust ventilation was fixed. Conclusions: Nurses in ambulatory care departments were exposed to FA. Therefore, the environment management of a workplace, the health management of a nurses, FA handling education and installing a FA cabinet with a local exhaust ventilation were needed because FA as a carcinogen was able to cause any cancer to a human body if it was emitted in air for long time.