• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.3
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• pp.182-194
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• 2009

This study was conducted to evaluate health status and to propose health protection measures of irregular plant construction workers in Yoesu National Industrial Complex (YNIC). The status of safety and health management was examined in five areas including safety and health education, work environment monitoring, health examination, health management record, and personal protective equipment (PPE) for plant construction workers. The safety training rate for plant construction workers was reached high at 91%, The training was mostly consisted of safety accident related things, but training on hazardous materials was found to be insufficient. Workplace monitoring results showed that the compliance rate for work environment for irregular construction workers was 54% and workplace monitoring during turnaround (TA) period with high risk of exposure to hazardous agents has not been implemented. While 61.4% of irregular workers received the general health examination but only 36.8% received the special health examination. The special health examination was found to be conducted only upon welders from 2-3 years ago. The issue of health management record upon irregular construction workers was not being implemented. In case of PPE, basic safety protective equipments such as safety shoes, safety belt, safety helmet were being supplied well while the supply rate of respirator for organic vapor was relatively low at 40%. Based on this study, two suggestions to maximize the utilization of the current safety and health program were made while boosting its effectiveness in protecting workers' health. First, the role of owners (petrochemical plant) related to safety and health should be strengthened. Second, in consideration of the characteristics of construction workers who usually engage in short term employment and frequent movement, community based health management organization is suggested that can overcome such structural problem and carry out the implementation of health examination and sustained health management.

• Journal of Preventive Medicine and Public Health
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• v.21 no.2 s.24
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• pp.284-294
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• 1988

To measure the mutagenic activity of micro-organic pollutants in drinking water, mutagenicity test was conducted using Salmnella typhimurium TA 98 strain on the water sample taken from three water supply stations and six tap water in Seoul in July and November 1987. The results were as follows : 1. The average amounts of organic matters in raw, treated, and tap water sampled in July were 0.38mg/l, 0.28mg/l, and 0.45mg/l. respectively, and sampled in November were 0.34mg/l, 0.24mg/l, and 0.22mg/l, respectively. The amount of organic matters of tap water sampled in November did not increase while that of tap water sampled in July increased compare to those of raw or treated water. 2. The amount of organic matters is the highest in neutral fraction compare to acidic and basic fractions. 3. In the five out of six tap water and raw water of Paldang and Kuui station sampled in July, the mutagenicity ratios were greater then two (both direct and indirect mutagenicity). 4. In the three out of six tap water and raw and treated water of Kuui station sampled in November, the mutagenicity ratios were greater than two. 5. While mutagenic activities were low in acidic and basic fraction, they were high in neutral fraction. The samples which had high mutagenic acitivity in the total amount also showed high mutagenic activity in neutral fraction. 6. While mutagenic acitivity was decreased after the treatement of water, it was increased in tap water as the distance from the water supply station increases.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.277-280
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• 2008

Enhancing the positioning precision is the primary pursuit of GPS users. To achieve this goal, most studies have focused on the relationship between GPS receiver clock errors and GPS positioning precision. This study utilizes undifferentiated phase data to calculate GPS clock errors and to compare with the frequency of cesium clock directly, thus verifying estimated clock errors by the method used in this paper. The relative frequency offsets from this paper and from National Standard Time and Frequency Laboratory of Taiwan match to $1.5{\times}10^{12}$ in the frequency instability, suggesting that the proposed technique has reached a certain level of quality. The built-in quartz clocks in the GPS receivers yield relative frequency offsets that are 3 to 4 orders higher than those of rubidium clocks. The frequency instability of the quartz clocks is on average two orders worse than that of the rubidium clock. Using the rubidium clock instead of the quartz clock, the horizontal and vertical positioning accuracies were improved by 26-78% (0.6-3.6 mm) and 20-34% (1.3-3.0 mm), respectively, for a short baseline. These improvements are 7-25% (0.3-1.7 mm) and 11% (1.7 mm) for a long baseline. Our experiments show that the frequency instability of clock, rather than relative frequency offset, is the governing factor of positioning accuracy.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.163-163
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• 1999

MOSFET, MESFET 그리고 MODFET는 Logic ULSIs, high speed ICs, RF MMICs 등에서 중요한 역할을 하고 있으며, 그것의 gate electrode, contact, interconnect 등의 물질로는 refractory metal을 이용한 CoSi2, MoSi2, TaSi2, PtSi2, TiSi2 등의 효과를 얻어내고 있다. 그중 TiSi2는 비저항이 가장 낮고, 열적 안정도가 좋으며 SAG process가 가능하므로 simpler alignment process, higher transconductance, lower source resistance 등의 장점을 동시에 만족시키고 있다. 최근 소자차원이 scale down 됨에 따라 TiSi2의 silicidation 과정에서 C49 TiSi2 phase(high resistivity, thermally unstable phase, larger grain size, base centered orthorhombic structure)의 출현과 그것을 제거하기 위한 노력이 큰 issue로 떠오르고 있다. 여러 연구 결과에 따르면 PAI(Pre-amorphization zimplantation), HTS(High Temperature Sputtering) process, Mo(Molybedenum) implasntation 등이 C49를 bypass시키고 C54 TiSi2 phase(lowest resistivity, thermally stable phase, smaller grain size, face centered orthorhombic structure)로의 transformation temperature를 줄일 수 있는 가장 효과적인 방법으로 제안되고 있지만, 아직 그 문제가 완전히 해결되지 않은 상태이며 C54 nucleation에 대한 physical mechanism을 밝히진 못하고 있다. 본 연구에서는 증착 시 기판온도의 변화(400~75$0^{\circ}C$)에 따라 silicon 위에 DC/RF magnetron sputtering 방식으로 Ti/Si film을 각각 제작하였다. 제작된 시료는 N2 분위기에서 30~120초 동안 500~85$0^{\circ}C$의 온도변화에 따라 RTA법으로 각각 one step annealing 하였다. 또한 Al을 cosputtering함으로써 Al impurity의 존재에 따른 영향을 동시에 고려해 보았다. 제작된 시료의 분석을 위해 phase transformation을 XRD로, microstructure를 TEM으로, surface topography는 SEM으로, surface microroughness는 AFM으로 측정하였으며 sheet resistance는 4-point probe로 측정하였다. 분석된 결과를 보면, 고온에서 제작된 박막에서의 C54 phase transformation temperature가 감소하는 것이 관측되었으며, Al impuritydmlwhswork 낮은온도에서의 C54 TiSi2 형성을 돕는다는 것을 알 수 있었다. 본 연구에서는 결론적으로, 고온에서 증착된 박막으로부터 열적으로 안정된 phase의 낮은 resistivity를 갖는 C54 TiSi2 형성을 보다 낮은 온도에서 one-step RTA를 통해 얻을 수 있다는 결과와 Al impurity가 존재함으로써 얻어지는 thermal budget의 효과, 그리고 그로부터 기대할 수 있는 여러 장점들을 보고하고자 한다.

• The Journal of Korean Academy of Prosthodontics
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• v.25 no.1
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• pp.71-94
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• 1987

This study was carried out to investigate the sound distortion following the alternation of the palatal plate thickness. For this study, 2 healthy male subjects (24-year-old) were selected. Born in Seoul, they both spoke Seoul dialect. First, their sounds of /na(나)/, /da(다)/, /1a(라)/, /ja(자)/, /cha(차)/, /ta(타)/, without inserting plates were recorded, and then the sounds with palatal plates of different thickness were recorded, successively. The plate was fabricated in 3 types, each palatal thickness being 1.0mm, 2.5mm, dentoalveolar portion 2.5mm, other residual portion was 1.0mm, successively. Each type plates named B, C, D-type, in succession. Series of analysis were administered through Computer(16 bit) to analyze the sound distortions. These experiments were analyzed by the LPC (without weighting, pre-weighting, post-weighting) of the consonants, vowels portion, formant frequency of the vowels and word duration of the consonants. The findings led to the following conclusions: 1. There was no correlation of the distortion rate on the 2 informants. 2. Generally, vowels were not affected by the palatal plate thickness in the formant analysis, however, more distortion was detected in the LPC analysis, especially C, D-type plates. 3. Consonants distortion was more evident in the C, D-type plate. 4. The second formant was most disturbed and reduced in the all consonants with insertion of the palatal plate, especially C, D-type plate. 5. Word duration was shortened in the plate inserted(except /ja/, /cha/), especially C, D-type. 6. It was found that dentoalveolar, hard palatal sounds were severely distorted in plate inserted, and they were mainly affected by the dentoalveolar portion thickness. 7. There was correlation between palatal thickness and consonants quality.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.5
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• pp.2263-2266
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• 2014

The aim of the study was to investigate the results of bladder irrigation with Water for Injection (WFI) after transurethral resection of bladder tumours for comparison with those for adjuvant use of BCG. A total of 239 patients (158 with single tumours, group A, and 81 with multiple tumours, group B) received continuous intravesical postoperative irrigation with WFI. Some 128 patients received intravesical irrigation with WFI, followed by weekly instillations of BCG (group C). Recurrence-free rate (RFR) and recurrence-free intervals (RFI) were recorded. RFR for those patients who received only intravesical irrigation with WFI (groups A and B) was 75.8%, 66.2% and 63.2% at the 1st, 2nd and 3rd year of follow up, respectively. Corresponding rates for group C were 61.7%, 55.4% and 49%. Median RFI in group B were 18, 11, 15, 15 and 12 months for Ta, T1, grade 1, grade 2 and grade 3 tumours, respectively. In group C corresponding intervals were 20, 33, 8, 20 and 42 months. BCG improved RFR only in T1 (p=0.014) and grade 3 tumours (p=0.007). In conclusion, postoperative bladder irrigation with WFI could increase RFR during the first and second year of follow up.

• Journal of Distribution Science
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• v.6 no.2
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• pp.41-60
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• 2008

This study examined state of local pharmaceuticals industry and investigated distribution system. The study found out associated problems as well as improvements of distribution system of local pharmaceuticals. Finally, to improve distribution system of local pharmaceuticals, the study investigated distribution system of 10 kinds of pharmaceuticals of 'J' Company being a leading local manufacturer of local pharmaceuticals, and found out improvements of the distribution system. The study collected and compiled 'J' Company's internal slips and reporting material from April 1, 2008 to July 31, 2008, and interviewed persons in charge continuously to find out state and problems of the distribution system.

• Journal of Oral Medicine and Pain
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• v.21 no.2
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• pp.265-277
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• 1996

The aim of this study was to investigate the electromyographic(EMG) activity of masticatory and cervical muscles according to chewing pattern in coronal plane during gum chewing. 70 patients with temporomandibular disorders and 30 dental students without any signs and symptoms of the disorders participated in this study. We measured the activity of masseter (MM), anterior temporalis(TA), sternocleidomastoideus(SCM) and trapezius muscle and recorded the chewing patterns using Biopak system synchronously. Chewing pattern was classified into S- or L-pattern by the midline opening path and short or long type by the lateral distance from midline. Obtained data were analyzed with SAS/STAT Program. The obtained results were as follows : 1. Generally, there was tended to be higher activity in the control group than in the patients group. 2. When comparing EMG activity according to preferred side, the muscle activity was tended to higher on the preferred chewing side than on the contralateral side. However, this difference is insignificant statistically 3. In unilateral affected patients, there was no difference in muscle activity between affected chewing side and unaffected chewing side except for the EMG of the temporalis anterior muscle. 4. Despite the varietal in each of the following variables, there mere no differences in EMG activity during gum chewing: chewing pattern in coronal plane and lateral distance of chewing. 5. The activity of SCM in chewing side was higher than that in contralateral side (p<0.001), but there was no difference in trapezius muscle. 6. In all of the control group, there was appeared L-chewing pattern than not involved the midline during preferred side chewing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.4
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• pp.871-876
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• 2005

Theme park automation system is developed by using the RFID sensor reader, IIS web server, ASP.NET and MSSQL database in this paper. Its operation is that park entrance people checked automatically when he who possessed the ta8 passed the reader acquisition bound and its tag information is sent to the host computer through the RS-232 data acquisition system. Tag information and time data will be stored in the RFID database tables and reused to extract and distribute the entrance people for the purpose of each arrangement of each entertainment devices. First of all, we developed interface program between host and reader and then, programmed the related web site and database connection function using ASP.NET with $C\#$ and MSSQ. We also design and make an production of external Ant. to extend the acquisition range up to $30\~40$ cm using copper PCB plate. We confirmed the performance through the RFID test bed site.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.339-342
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• 2003

The corrosion characteristics of Copper by oxidizers in Cu CMP slurry has been investigated. Key experimental variables that has been investigate are the corrosion rate by different oxidizers containing slurry of Cu CMP. Oxidizers in Cu CMP slurry reacts with Cu surfaces to raise the oxidation state of the metal via a reduction-oxidation reaction, resulting in either dissolution of the Cu or the formation of Ta surface film on the metal.[1] When Cu films were corroded adding each oxidizer, corrosion rate increased as much as higher Icorrosion. The corrosion rate of Cu was the largest as added $(NH_4)_2S_2O_8$. The higher content of Urea Hydrogen peroxide was, the higher corrosion rate was measured. Putting in tartaric acid as complexing agent, the corrosion rates of the compounds(Urea hydrogen peroxide+$H_2O_2$) are uniformly. As a result of Cu corrosion by $Cu(NO_3)_2$, the high corrosion rate was determined by even small amounts of $Cu(NO_3)_2$. Consequently, this can be explained by assuming that corrosion by oxidizers has primary effects on the removal rate of Cu and the proper oxidizer needs to be chosen in accordance with relationship of each slurry agent.