• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.1 no.1
• /
• pp.23-31
• /
• 1976

When Television signal of VHF and UHF channel is retransmitted at the relay system with 6MHz Bandwidth including video and aural signals, the image is often affected with the unnatural changes of output amplitude frequency response within ttle region of dual sideband near to the carrier frequency. These phenomena are caused by the unnecessary lower sideband due to the spurious emission at the local oscillator, the nonlinear distortion in the linear amplifier, the intermoudulation distortion with the components of neighboring signal, the AM-PM conversion, and the envelope delay distortion. From the output characteristics, considering above results, the chief cause is caused by nonlinear response and has an effect on the bias states. Finally, it is confirmed that the effects on neighboring signal appear high in case of Down conversion than Up conversion and obtained the method for reducing the effects on the system.

• Child Health Nursing Research
• /
• v.4 no.2
• /
• pp.265-273
• /
• 1998

The purpose of this study was to identify the children's sleeping patterns, such as the sleeping hours and the nature of sleep disruptions following hospitalization and its accompanying factors. The data were collected from December, 1997 to March, 1998 using a questionnaire developed by researchers. The subjects were 76 children in a hospital. The results of this study were summarized as follows : 1. The average sleeping hours (sleep duration) at night were 10 hours and 10 minutes and 9 hours and 9 minutes before and after hospitalization respectively. There was a significant difference (p<0.01). The average sleeping hours in the day time were 1 hour 28 minutes and 2 hours and 26 minutes before and after hospitalization respectively. There was a significant difference(P<0.01). 2. The mean bed time(sleep onset) was 10: 22 pm and 10 : 28 pm before and after hospitalization respectively. There was no significant difference. 3. The mean hour of rising(sleep termination) was 7: 54 am 7 : 08 am before and after hospitalization respectively. There was a significant difference (p<0.01). 4. The mean number of sleep disruption was 0.72 and 1.94 before and after hospitalization respectively. There was a significant difference(P<0.01). The sleep disruptions were influenced by crying of other children(53.9%), lights(28.9), nursing procedures(18.4%), noise of TV(17.l%) and noise of visitors (15.8%).

• Child Health Nursing Research
• /
• v.18 no.2
• /
• pp.85-94
• /
• 2012

Purpose: Instead of a chaotic non circadian environmental approach, continuing regular day-night rhythm in neonatal nurseries may benefit the development of preterm infants. The purpose of this study was to define the effects of cycled lighting on circadian rhythms of premature infants. Methods: The experimental group included 15 preterm infants, and the control group, 15 premature infants in the NICU of a general hospital in Seoul. All infants were between 32 and 37 weeks' postconceptional age. The experimental group infants were provided with cycled lighting before discharge. The incubator or bassinet cover of the experimental group was off between 7 AM and 7 PM, and was covered between 7 PM and 7 AM. Results: There were significant differences in the NNNS score ($p$=.039), and some significant differences in the sleep-activity pattern between the experimental group and the control group, but distinct differences in sleep-activity patterns between the two groups could not be defined. Conclusion: The results of this study suggest that cycled lighting can be helpful in the neurobehavioral development of preterm infants. By modifying the NICU environment to provide a more developmentally supportive milieu, nursing professionals can better meet the infants' physiologic and neurobehavioral needs.

• Journal of Korean Society for Atmospheric Environment
• /
• v.30 no.3
• /
• pp.233-244
• /
• 2014

The objective of this study was to explore the characteristics of concentration of indoor air pollutants, such as $PM_{10}$, $CO_2$, and $NO_2$, measured by tele-monitoring system in a Seoul Metropolitan underground railway station from January 1, 2008 to December 31, 2012. The annual average concentration of indoor air pollutants actually varied over a wide range and was found to exhibit marked variation with time and measurement sites (tunnel inlet, platform, and concourse). After installing platform screen doors, the average $PM_{10}$ concentration on platform and concourse was decreased by 43.8% and 31.2%, respectively during the study periods. The relationship between the concentration of $PM_{10}$ and meteorological parameters (relative humidity and rainfall) or the Asian dust events was regarded as statistically significant. The correlations between the number of boarding/alighting passengers and $PM_{10}$, $CO_2$, and $NO_2$ were calculated. A p-value of less than 0.01 was regarded as significant except $NO_2$. The I/O ratio of $PM_{10}$ concentration was elevated after a congested time (about 08:00 am). The average I/O ratios of $NO_2$ were observed in concourse and platform on 03:00 am with $1.76{\pm}0.91$ and $1.50{\pm}0.51$, respectively. The average daily variation of standard excess rate of $PM_{10}$ and $NO_2$ concentration in concourse and platform was investigated. The highest standard excess rate was observed on 21:00 (09:00 pm).

• Journal of agricultural medicine and community health
• /
• v.12 no.1
• /
• pp.94-101
• /
• 1987

Enterobiasis is common helminthic infections found in man. But control of this disease is still troublesome because of its difficulty in the d diagnosis and prevention of infection. Considering the difficulty of accurate diagnosis of pinworm infection, which is very common and somewhat pathogenic, reevaluation of cellotape anal swab method for the diagnosis of enterobiasis was performed. A total of 147 children ranging the ages of 1-12 years in 3 orphanages in the suburbs of Seoul, Korea was subjected for this study. Repeated cellotape anal swabs were carried out against 70 children, 7 times for 3 days interval, in the morning 6am. Finally 10 mg/kg body weight pyrantel pamoates were given to all children including egg negative cases and whole stools of 3 following successive days were collected for the confirmation of residual worm ourden at the time of treatment. Cellotape anal swabs were also performed to another 77 children at 6am, 3pm, 9pm, twice for 3 days interval. The resultant findings were summarized as follows; 1) While the each time average detection rate of Enterobius egg was 28.8% in this study group, the accumulative detection rate up to 7th examination was 62.8%. The accumulative detection rate rose continuously up to 6th examination. 2) After administration of pyrantel pamoate 10 mg/kg body weight, final infection rate was increased to 72.9% by adding worm positive cases who didn't show any evidence of infection in the cellotape anal swabs. 3) Although pinworms were detected in 35 among 70 children treated, 7 cases (20%) of them were egg negative cases in 7 consecutive cellotape anal swabs. 4) Pinworms were expelleded in 14 (87.5%) among 16 children whose swab result was positive in the last examination which was done concurrently with drug administration. 5) Estimated infection rate calculated by best asymptotically normal estimate of Neuman from Moriya's modification revealed 71.5% similar to 72.9% of present results. 6) The result of anal swab performed at 6am was higher than that of 3pm or 8pm. In conclusion, cellotape anal swab method for Enterobius vermicularis infection was considered as method having relatively high positive accuracy. However to gain the reliable infection rate, at least 6 examination is required in the group with 25-30% infection rate by single swab. Moriya's modification of Neuman could be used efficiently in the mass control of this diease for the estimation of true infection rate of E. vermicularis in the sampled population.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.15 no.2
• /
• pp.280-285
• /
• 2015

A fully integrated high-efficiency linear CMOS power amplifier (PA) is developed for 802.11n WLAN applications using the 65-nm standard CMOS technology. The transformer topology is investigated to obtain a high-efficiency and high-linearity performance. By adopting a 2:2 output transformer, an optimum impedance is provided to the PA core. Besides, a LC harmonic control block is added to reduce the AM-to-AM/AM-to-PM distortions. The CMOS PA produces a saturated power of 26.1 dBm with a peak power-added efficiency (PAE) of 38.2%. The PA is tested using an 802.11n signal, and it satisfies the stringent error vector magnitude (EVM) and mask requirements. It achieves -28-dB EVM at an output power of 18.6 dBm with a PAE of 14.7%.

• KIEAE Journal
• /
• v.11 no.2
• /
• pp.83-90
• /
• 2011

This study has observed 12 parks (20 spots) in Seoul to know the number of users, gender, age groups for the units of 30 minutes from 06:00AM till 10:00PM. According to the systematic characteristic of the surveyed outdoor exercise place, the details of their users during the summer time were analyzed from the objective viewpoint. Major results of analysis are as follows: Firstly, in case of the riverside of the Han River 07:00AM marked a mini peak and 21:00PM reached the peak, and in case of sub-stream neighborhoods, 21:00PM showed only one peak. On the other hand, in case of neighborhood parks (including pocket park) no peak time was noticeable. Secondly, in case of the riverside of the Han River and the neighborhoods of sub-streams, people used the exercise equipment remarkably at night, and in case of neighborhood parks people used the exercise equipment a little bit more in the morning than in the afternoon. Thirdly, in case of nights in summer the riverside of the Han River was preferred by men, while the neighborhoods of sub-streams were preferred by women and the neighborhood parks showed no difference in the number of users among men and women. Fourthly, differently from men, women do not regard the exercise so seriously as men and their purpose of using outdoor exercise place is to use their leisure time mostly with their family members or neighbors, and women prefer light and comfortable exercises. Fifthly, in summer even those who like to exercise a lot like to exercise in the morning to avoid summer heat. Therefore, provision of shades in summer is very important.

• Fisheries and Aquatic Sciences
• /
• v.25 no.11
• /
• pp.537-548
• /
• 2022

Apparent digestibility coefficients (ADCs) of dry matter, crude protein, crude lipid, nitrogen-free extract, energy and essential amino acids in animal-based feed ingredients were determined for olive flounder (Paralichthys olivaceus). A reference diet (RF) was formulated to contain 1.0% chromic oxide (Cr₂O₃) as an inert indicator. Nine test diets were formulated to contain RF and one of the feed ingredients (pollock meal [PM], jack mackerel meal [JMM], anchovy meal [AM], cod meal [CM], sardine meal [SM], sand eel meal [SEM], tuna meal [TM], meat meal [MM] and squid liver meal [SLM]) at a 7:3 ratio in each diet designated as PM, JMM, AM, CM, SM, SEM, TM, MM and SLM, respectively. Olive flounder, averaging 150 ± 8.0 g, were stocked at a density of 25 fish per tank in 400-L fiberglass tanks attached with fecal collection columns. Feces were collected from triplicate groups of fish one time a day for four weeks. Dry matter and crude protein ADCs of CM and SEM were significantly higher than the other tested ingredients. Lipid ADCs of JMM, CM and SEM were significantly higher than the other test ingredients. Energy ADCs of CM and SEM were significantly higher than that of the other tested ingredients. The availability of amino acids in CM was generally higher than the other animal protein sources. PM exhibited the lowest amino acid availability among the treatments. Interestingly, MM exhibited significantly higher nutrient digestibility than several marine-based ingredients. However, CM and SEM are seeming to be highly digestible and effective to use in olive flounder diet compared to the other tested ingredients. Overall, the results of this study provide information about the bioavailability of nutrients and energy in animal feedstuffs to apply when formulating cost-effective practical feeds for olive flounder.

• Journal of Dairy Science and Biotechnology
• /
• v.26 no.1
• /
• pp.1-4
• /
• 2008

Melatonin is one of the functional hormones in the milk and found in all mammalian species. The primary motivation for the use of melatonin as a supplement is as a natural aid to better sleep. Melatonin contents in milk vary according to the naturally occurring factors such as seasons and milking times. As a number of studies indicate melatonin supplementation helps to reduce the age-related decline in hormone production and overall enhancement of health, the more detailed studies are required to know the nature of milk derived hormones and to clarify them as a functional value adaptation. The objectives of this study were to examine the change of melatonin content in bovine milk during different milking times at the two dairy farms and during dairy process including homogenization and pasteurization. Commercial dairy products including night time milking products(night milk) marketed in Japan were also investigated. Melatonin content was determined by radioimmunoassay using 125I. Individual milk was collected from lactating Holstein cows at Kyong-Ki province in Korea. At farm A, the melatonin contents milking at 4 a.m. was higher than those of 7 p.m. and 12 p.m.($6.90{\pm}3.55,\;2.01{\pm}1.47$ and $0.16{\pm}0.04pg/mL$, respectively). At farm B, the mean melatonin contents milked from 24:00 AM to 05:00 AM have shown the highest contents ($4.65{\pm}$0.72pg/mL), and milking samples of the rest time had very little or non-detection of melatonin contents. Melatonin contents of commercial night milk samples were about 5 times higher than those of other common milk products. These results suggested that melatonin might be heat-resistant and commercial dairy process might not affect its contents in the final products.

• Particle and aerosol research
• /
• v.20 no.3
• /
• pp.79-94
• /
• 2024

Exposure to ambient particulate matter (PM) 2.5 can impair alveolar macrophages (AMs) functions and induce pathological conditions. This study explores the impact of PM2.5 exposure on AMs, focusing on gene expression changes and functional alterations. Murine AMs cell line MH-S were exposed to PM2.5 at a concentration of 100 ㎍/ml for durations of 3 and 48 hours. After 3 hours of exposure, genes involved in inflammatory and immune responses were activated, including TNF and B-cell receptor signaling pathways. In contrast, 48 hours of exposure significantly altered genes related to cell proliferation, apoptosis, and immune processes, with PI3K-Akt and cytokine-cytokine receptor interaction pathways. PM2.5 initially triggers immune responses; however, prolonged exposure over 48 hours impairs AM functions risk of chronic inflammation and cancer. This research provides foundational data for therapeutic approaches related to PM2.5 exposure.