• 한국전자파학회논문지
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• 제17권12호
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• pp.1231-1239
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• 2006

본 연구는 수동 루프 축소 시험 장치를 이용하여 수동 루프 유형별 자기장 저감 효과를 분석하였다. 본 연구에서는 수직 2회선 선로 및 수평 선로를 대상으로 실험을 통하여 향후 실증 시험 선로에 적용할 수동 루프의 자기장 저감 효과를 검토하였다. 그 결과 수동 루프 채용으로 선로 리액턴스 보상이 없어도 50 % 이상의 송전 선로의 자기장 저감 효과를 얻을 수 있음을 확인함으로써 실증 선로 수동 루프 적용 방안을 확보하였다. 대부분 우리나라 송전 선로에 채용되는 수직 2회선 선로에서는 수평 루프보다는 수직 루프가 자기장 저감율에 보다 효과적이었으며 차폐 영역에서도 근거리뿐만 아니라 원거리까지도 효과가 좋음을 알 수 있었다. 또한, 수동 루프를 3 턴으로 설치하는 경우가 1 턴에 비해 2배정도 자기장 저감 효과가 있음을 확인하였다.

• Clinical and Experimental Pediatrics
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• 제64권5호
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• pp.239-246
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• 2021

Background: The consequences of severe acute respiratory syndrome corona virus 2 on mother and fetus remain unknown due to a lack of robust evidence from prospective studies. Purpose: This study evaluated the effect of coronavirus disease 2019 (COVID-19) on neonatal outcomes and the scope of vertical transmission. Methods: This ambispective observational study enrolled pregnant women with COVID-19 in North India from April 1 to August 31, 2020 to evaluate neonatal outcomes and the risk of vertical transmission. Results: A total of 44 neonates born to 41 COVID-19-positive mothers were evaluated. Among them, 28 patients (68.3%) (2 sets of twins) were delivered within 7 days of testing positive for COVID-19, 23 patients (56%) (2 sets of twins) were delivered by cesarean section; 13 newborns (29.5%) had low birth weight; 7 (15.9%) were preterm; and 6 (13.6%) required neonatal intensive care unit admission, reflecting an increased incidence of cesarean delivery and low birth weight but zero neonatal mortality. Samples of cord blood, placental membrane, vaginal fluid, amniotic fluid, peritoneal fluid (in case of cesarean section), and breast milk for COVID-19 reverse transcription-polymerase chain reaction tested negative in 22 prospective delivery cases. Nasopharyngeal swabs of 2 newborns tested positive for COVID-19: one at 24 hours and the other on day 4 of life. In the former case, biological samples were not collected as the mother was asymptomatic and her COVID-19 report was available postdelivery; hence, the source of infection remained inconclusive. In the latter case, all samples tested negative, ruling out the possibility of vertical transmission. All neonates remained asymptomatic on follow-up. Conclusion: COVID-19 does not have direct adverse effects on the fetus per se. The possibility of vertical transmission is almost negligible, although results from larger trials are required to confirm our findings.

• 한국해양공학회지
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• 제22권4호
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• pp.27-33
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• 2008

One of the central problems in astudy of the coastal surface wave environment is predicting the transformation of waves as they propagate toward the shore. The transformation is mainly due to the existence of obstacles, such as breakwaters and vertical cylinders. In general, the types of wave transformation can be classified as follows: wave diffraction, reflection, transmission, scattering, radiation, et al. This research dealtwith wave transmission and dissipation problems for two dimensional irregular waves and vertical circular cylinders. Using the unsteady mild slope equation, a numerical model was developed to calculate the reflection and transmission of regular waves from a multiple-row circular breakwater and vertical cylinders. In addition, hydraulic model experiments were conducted with different values for the properties between tire piles and the opening ratio (distances) between the rows of the breakwater. It was found that the transmission coefficients decreased with a decrease in the opening ratio and an increase in the rows of vertical cylinders. A comparison between the results of hydraulic and numerical experiments showed reasonable agreement.

• 한국해안·해양공학회논문집
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• 제27권5호
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• pp.345-352
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• 2015

본 연구에서는 직립식 구조물의 전달파고계수 산정을 위한 2차원 수리실험을 실시하였다. 불규칙파를 입사파로 적용하였으며 직립식 구조물에 대한 전달파고계수 산정식을 제안하고, Goda(1969) 등의 결과와 비교하였다. Goda(1969)의 결과는 입사파로 규칙파를 적용한 결과로서 불규칙파를 적용한 본 실험의 결과와 차이를 보였다. Goda의 결과가 본 연구에 비하여 크게 전달파고계수를 제시하는 것을 알 수 있었다. 또한 Goda는 직립벽에 대하여 평균, 상한 및 하한에 대한 계수값을 제시하였으나(d=h조건), 본 연구에서는 각각의 설계요소(구조물 폭, 수심, 파장 등)가 전달파고계수에 주는 영향을 계수를 통하여 정량적으로 제시하였다. 또한 여유고가 0인 조건에 대한 에너지보존 및 전달파고 특성을 제시하였다.

• Clinical and Experimental Pediatrics
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• 제64권4호
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• pp.157-164
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• 2021

Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in December 2019, a small number of coronavirus disease 2019 (COVID-19) cases in neonates have been reported worldwide. Neonates currently account for only a minor proportion of the pediatric population affected by COVID-19. Thus, data on the epidemiological and clinical features of COVID-19 in neonates are limited. Approximately 3% of neonates born to mothers with COVID-19 reportedly tested positive for SARS-CoV-2. Current limited data on neonates with COVID-19 suggest that neonatal COVID-19 shows a relatively benign course despite a high requirement for mechanical ventilation. However, neonates with pre-existing medical conditions and preterm infants appear to be at a higher risk of developing severe COVID-19. The greatest perinatal concern of the COVID-19 pandemic is the possibility of vertical transmission, especially transplacental transmission of SARS-CoV-2. Although direct evidence of the vertical transmission of SARS-CoV-2 is lacking, its possibility during late pregnancy cannot be ruled out. This review summarizes available case studies on COVID-19 in neonates and introduces what is currently known about neonatal COVID-19 with focus on its vertical transmission.

• International Journal of Internet, Broadcasting and Communication
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• 제4권2호
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• pp.22-27
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• 2012

The design characteristics of circular vertical-cavity surface-emitting lasers are studied by using a newly developed equivalent network. Optical parameters, such as the stop-band or the reflectivity of periodic mirrors and the resonance wavelength, are explored for the design of these structures. To evaluate the differential quantum efficiency and the threshold current density, a transverse resonance condition of modal transmission-line theory is also utilized. This approach dramatically reduces the computational time as well as gives an explicit insight to explore the optical characteristics of circular vertical-cavity surface-emitting lasers (VCSELs).

• Nuclear Engineering and Technology
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• 제36권1호
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• pp.12-23
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• 2004

In the present study a new measurement technique has been developed, which uses an ultrasonic transmission signal in order to identify the vertical two phase flow pattern. The ultrasonic measurement system developed in the present study not only provides the information required for the identification of vertical two phase flow patterns but also makes real time identification possible. Various vertical two phase flow patterns such as bubbly, slug, churn, annular flow etc. have been accurately identified with the present ultrasonic measurement system under atmospheric condition. In addition, the present test apparatus can practically simulate the ultrasonic propagation characteristics under high temperature and high pressure systems. Therefore, it is expected that the present ultrasonic flow pattern identification technique could be applicable to the vertical two phase flow systems under high temperature and high pressure conditions.

• 한국언론정보학보
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• 제62권
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• pp.200-222
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• 2013

최근의 망 중립성 논쟁은 전송 차등화와 그에 따른 비용정산으로 전환되고 있으며, 이와 같은 현상은 수직 계열화된 네트워크 사업자가 경쟁 사업자를 배제하기 위한 전략이라는 주장이 제기되고 있다. 이와 같은 맥락에서 본 연구는 네트워크 사업자의 전송 차등화 사례를 분석하고, IX 시장에서 수직 계열화된 네트워크 사업자의 문제점을 검토했다. 연구결과 전송 차등화 현상은 향후 OTT나 스마트TV 응용 프로그램과 같이 범용 망을 사용하는 콘텐츠에 대한 차별화 현상을 가중시킬 것으로 전망되며, 관련법에서는 이와 같은 문제를 해결할 수 있는 방법이 애매한 것으로 나타났다. 더욱이 ISP 시장에서 수직 계열화되어 있고, 상업적으로 운영되는 IPS 사업자들은 경쟁 사업자를 차별하고 이와 같은 현상은 관련법에서도 노골적으로 명시되고 있는 것으로 나타났다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제2권1호
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• pp.109-115
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• 1999

Hepatitis C virus (HCV) has been identified as an important cause of posttransfusion hepatitis, but vertical transmission of chronic infected HCV RNA positive mothers has been documented in some cases. The reports of the risk of perinatal infection have been widely varied in the literature. The authors experienced one case of vertical transmission of HCV in an infant of a mother who had hepatitis C during pregnancy. At admission, HCV RNA (+), Ig G anti HCV (+) and Ig M anti HCV (+) were found in the mother. Also at admission, HCV RNA (+), Ig G anti HCV (+), Ig M anti HCV (+), elevation of liver aminotransferase level and hepatosplenomegaly on ultrasonography were found in the baby on day 31. HCV RNA (-), Ig M anti HCV (-) and normal of liver aminotransferase level were noted on day 250 in the serum of the infant. We used reverse transcriptase polymerase chain reaction (RT-PCR) technique to find a very small amount of HCV RNA in the serum. All the findings suggest vertical transmission of HCV RNA from mother to infant during 3rd trimester of pregnancy.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.573-574
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• 2006

This research deals with the wave transmission and dissipation problems for two dimensional regular waves and s vertical circular cylindersr. Using the unsteady mild slope equation, a numerical model has been developed to calculate the reflection and transmission of regular waves from a multiple-row vertical circular cylinders. In addition hydraulic model experiments have been conducted with different values of properties between the cylinders and opening ratio (distances) between the rows of the cylinders. It is found that the transmission coefficients decrease with decreasing the opening ratio and increasing the rows of vertical cylinders. Comparison between hydralic and numerical experiments results shows resonable agreement.