• 분석과학
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• 제17권4호
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• pp.302-307
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• 2004

환경시료중의 극미량의 악티늄계 동위원소들을 분석하기는 무척 어렵다. 이들 원소들은 개별 분리하는 작업이 필요하며, 알파분광법으로 분석한 어떤 핵종들은 검출감도도 높은 편이다. 이런 극미량의 악티늄계 동위원소들을 분석하기 위해 용매추출법이 결합된 TRU-Spec 이온교환수지와 음이온 교환수지를 사용하여 악티늄계 원소들을 분리한 후 알파분광법으로 검출하였다. 그리고 U과 Th의 검출한계를 낮추기 위해 중성자방사화분석법을 적용하였다. 중성자방사화분석법을 적용하기 위한 바탕물질로 고순도 V foil을 사용하여 검출감도를 10배 향상시킬 수 있었으며, 이 분석법을 표준시료인 NIST-4354, IAEA-368 퇴적물 시료에 적용한 결과 표준값과 10% 이내에서 잘 일치하였다.

• 한국해안·해양공학회논문집
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• 제35권4호
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• pp.84-94
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• 2023

재현기간에 따른 설계주기 추정에는 일반적으로 파고-주기 관계곡선을 이용한다. 본 연구에서는 설계주기 추정을 위한 파고-주기 관계곡선의 매개변수를 선형, 로버스트 선형, 비선형 함수를 이용하여 추정하고 그 계수를 비교-평가하였다. 매개변수 추정에 사용한 자료는 해양수산부(2019) 설계파고 추정에 사용한 연 최대 파고-주기 자료이며, 태풍, 비태풍 조건으로 구분하여 매개변수 추정에 이용하였다. 추정 매개변수는 해역의 지점에 따라 뚜렷한 차이를 보였으며, 추정기법의 경우에는 태풍 조건의 자료의 경우 비선형과 선형 기법이 큰 차이를 보이고 있는 것으로 파악되었다. 또한 SPM 공식과 GODA 공식을 평균하여 추정하는 Suh et al.(2008, 2010) 제안 방법은 절편 매개변수는 과소추정, 경사 매개변수는 과대 추정하는 것으로 파악되었으며, 해역의 국지적인 특성 반영에는 한계가 있는 것으로 판단된다.

• Journal of Chest Surgery
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• 제57권3호
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• pp.272-280
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• 2024

Background: The phenomenon known as the "weekend effect" impacts various medical disciplines. We compared outcomes between regular hours and off hours to investigate the presence of the weekend effect in extracorporeal cardiopulmonary resuscitation (ECPR). Methods: Between January 2018 and December 2020, 159 patients at our center were treated with veno-arterial extracorporeal membrane oxygenation (ECMO) for cardiac arrest. We assessed the time required for ECMO preparation, the rate of successful weaning, and the rate of in-hospital mortality. These factors were compared among regular hours ("daytime": weekdays from 7:00 AM-7:00 PM), off hours on weekdays ("nighttime": weekdays from 7:00 PM-7:00 AM), and off hours on weekends and holidays ("weekend": Fridays at 7:00 PM to Mondays at 7:00 AM). Results: The time from the recognition of cardiac arrest to the arrival of the ECMO team was shortest for the daytime group and longest for those treated over the weekend (daytime, 10.0 minutes; nighttime, 12.5 minutes; weekend, 15.0 minutes; p=0.064). The time from the ECMO team's arrival to ECMO initiation was shortest for the daytime and longest for the nighttime group (daytime, 13.0 minutes; nighttime, 18.5 minutes; weekend, 14.0 minutes; p=0.028). No significant difference was observed in the rate of successful ECMO weaning (daytime, 48.3%; nighttime, 39.5%; weekend, 36.1%; p=0.375). Conclusion: In situations involving CPR, the time to arrival of the ECMO team was longer during off hours. Furthermore, ECMO insertion required more time at night than during the other periods. These findings warrant specific training in decision-making and emergent ECMO insertion.

• Tribology and Lubricants
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• 제27권4호
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• pp.213-217
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• 2011

In this study, friction characteristics using elastomeric actuator with Magneto-rheological (MR) materials are identified. Typically, Magneto-rheological materials are divided into two groups by MR fluid in fluid state and MR elastomer in solid state like rubber. The stiffness characteristics of Magneto-rheological material can be changed as magnetic field is applied. MR fluid has been applied to various industry fields such as to brake, clutch, damper, engine mount and etc. However, MR fluid has been used under the sealed condition to prevent leaking issues. In order to overcome these problems, MR elastomer that has same property as MR fluid has been developed and studied. MR elastomer mainly consists of polymer material such as natural rubber or silicon rubber with particles that can be polarized with magnetic field. And it is called as a smart material since its stiffness and damping characteristics can be changed. In this study, MR elastomer is produced and pin-on-disc tests are carried out to identify the friction characteristics of the material. Several test conditions are applied to evaluate the feasibility to use as a smart actuator in the field of vibration control.

• 한국위성정보통신학회논문지
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• 제6권1호
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• pp.97-102
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• 2011

현재 국내 라디오 방송은 디지털 방식이 아닌 아날로그 방식을 통해 서비스 되고 있다. 디지털라디오란 기존의 FM/AM 라디오를 디지털 신호로 전송하는 것으로 보다 깨끗한 음질과 교통, 날씨정보 등 다양한 부가 서비스를 제공할 수 있다는 장점이 있다. 이 밖에도 라디오가 디지털로 전환되면 갈수록 늘어나는 FM 주파수에 대한 수요도 충족시킬 수 있을 것으로 기대하고 있다. 디지털 라디오 방식중 하나인 DRM+는 배치하고자하는 지역의 주파수 사용현황에 따라 상대적으로 간섭이 적은 대역이라면 어디든 배치할 수 있다. 본 논문에서는 DRM+ 시스템에 대해 간단히 설명하고, 현재 사용 중인 주파수 현황을 알아본 후, 그에 맞는 DRM+후보 채널 도출 방안을 제시하고, 기존 아날로그 방송과 DRM+의 전파 간섭영향을 모의실험을 통해 검증 하였다.

• 한국기계가공학회지
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• 제14권4호
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• pp.134-139
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• 2015

PolyJet technology is an additive manufacturing (AM) technology commonly used for modeling, prototyping, and production applications. It is one of the techniques used for 3D printing. The PolyJet technique is a process that joins materials to fabricate a product from 3D CAD data in a layer-by-layer manner. The orientation of a layer can affect the mechanical properties of the product manufactured by the PolyJet technique because of its anisotropy. In this paper, tensile and shearing tests of specimens were developed with the PolyJet technique in order to study the mechanical properties according to the orientation of a layer. The mechanical properties of the specimens were determined on the basis of true stress-strain curves from tensile and shearing tests. In addition, the tensile and shearing tests were simulated under the same conditions as those of experiment, and the experiment and simulated results were compared. Through this study, the fracture criteria could be established.

• 대한암한의학회지
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• 제10권1호
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• pp.87-91
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• 2005

Objective: It is the aim of the present paper to derive further studies evaluating the effectiveness of oriental medical treatment on SCLC patients. We present a case of SCLC patient who survives over 8 years. Method: We followed all of treatments and examination. We prescribed to the patient what to take HangAmDan (HAD) three times a day. Chest X-ray was performed to evaluate the therapeutic efficacy. Results and conclusion: The patient survives over 8 years. Chest X-rays were shown partial regression. Conclusion: This case may give us a possibility of that oriental medical treatment offers potential benefits for patients with SCLC.

• 대한한방내과학회지
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• 제28권3호
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• pp.662-669
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• 2007

Objectives : The aim of the present study is to derive further studies evaluating the effectiveness of oriental medical treatment on colon cancer patients. We present a case of a patient diagnosed with colon cancer with colon cancer with liver metastasis who has survived more than 8 years. Methods : We followed all of treatments and examination. We prescribed the patient to take HangAm-dan(HAD) three times a day for 5 years and 1 month from January, 2000 to February, 2005. Abdominal computed tomography(CT) was performed to evaluate the therapeutic efficacy and measuring concentration of carcinoembryonic antigen(CEA) in blood serum was also performed to monitor therapeutic response. Results : The patient was diagnosed with liver metastasis in September of 1999 but has survived for over 8 years since. Abdomen CT show no interval change. Conclusions : This case may give us a possibility that oriental medical treatment offers potential benefits for patients with colon cancer.

• Bulletin of the Korean Chemical Society
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• 제34권1호
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• pp.79-88
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• 2013

$LiFePO_4$ is a promising active material (AM) suitable for use in high performance lithium-ion batteries used in automotive applications that require high current capabilities and a high degree of safety and reliability. In this study, an optimization of the electrode design parameters was performed to produce high capacity lithium-ion batteries based on $LiFePO_4$/graphite electrodes. The electrode thickness and porosity (AM density) are the two most important design parameters influencing the cell capacity. We quantified the effects of cathode thickness and porosity ($LiFePO_4$ electrode) on cell performance using a detailed one-dimensional electrochemical model. In addition, the effects of those parameters were experimentally studied through various coin cell tests. Based on the numerical and experimental results, the optimal ranges for the electrode thickness and porosity were determined to maximize the cell capacity of the $LiFePO_4$/graphite lithium-ion batteries.

• 대한약침학회지
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• 제3권2호
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• pp.41-54
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• 2000

This study was undertaken to determine if Plantaginis Semen Herbal Acupuncture(PSA) has a protective effect against glycerol-induced acute renal failure in rats. Rats were dehydrated for 24hr and then injected with 8 ml/kg of $50\%$ glycerol, one-half of dose in each hindlimb muscle. In experiments for PSA effect, rats received 0.1 ml of PSA extraction in both sides of corresponding Shenso($BL_{23}$) of human body for 3 days after injection of glycerol. The experimental group were di vided into the Normal group, the Control group, the PSA group. Glycerol injection decreased glomerular filtration rate and increased urine volume, serum creatinine, BUN level and fractional excretion of glucose, $Na^+$, $K^+$ and $CI^-$. These result show that glycerol injection result in acute renal failure. PSA significantly increased glomerular filtration rate and significantly decreased serum creatinine, BUN level and fractional excretion of glucose, $Na^+$ and $CI^-$ as compared Control group. This suggests that PSA could be used in prevention and treatment of acute renalfailure. However, the precise mechanisms of PSA protection remain to be determined.