Contrast-enhanced endoscopic ultrasonography: advance and current status

장성일,이동기 대한초음파의학회 2014 ULTRASONOGRAPHY Vol.33 No.3

Endoscopic ultrasonography (EUS) technology has undergone a great deal of progress along withthe color and power Doppler imaging, three-dimensional imaging, electronic scanning, tissueharmonic imaging, and elastography, and one of the most important developments is the abilityto acquire contrast-enhanced images. The blood flow in small vessels and the parenchymalmicrovasculature of the target lesion can be observed non-invasively by contrast-enhancedEUS (CE-EUS). Through a hemodynamic analysis, CE-EUS permits the diagnosis of variousgastrointestinal diseases and differential diagnoses between benign and malignant tumors. Recently, mechanical innovations and the development of contrast agents have increased theuse of CE-EUS in the diagnostic field, as well as for the assessment of the efficacy of therapeuticagents. The advances in and the current status of CE-EUS are discussed in this review.

러시아-우크라이나 전쟁과 에너지 안보 : 해상수송로 안보 관점

장성일 제주평화연구원 2022 JPI 정책포럼 Vol.2022 No.6

본 연구에서는 러시아-우크라이나 전쟁으로 발생한 해상수송로 안보 문제가 어떻게 에너지 안보와 연 결되는지, 그리고 이러한 문제가 한국에 주는 시사점이 무엇인지 살펴보고자 한다. 러시아는 우크라이나를 침공한 직후 흑해를 봉쇄했고 곡물을 수출하는 우크라이나 항구 도시들도 봉쇄됨에 따라 세계적인 식량위 기가 촉발되었다. 에너지 안보에서 해상수송이 중요한 이유는 석유(원유)나 천연가스와 같은 주요 에너지 자원이 필요한 곳으 로의 수송이 많은 경우에 해상수송을 통해서 이루어지기 때문이다. 해적활동, 해상테러리즘, 영유권 주장 등으로 인한 국가 간 해양분쟁을 포함하여 미중 경쟁 같은 국가 간 갈등 등 다양한 요인이 해상수송의 안보를 위태롭게 할 수 있고, 미중 경쟁이 격화될 가능성이 높아 주요 해상수송로 안보가 위협받을 가능성이 있다. 에너지원의 수입을 해상수송에 의존하는 한국 입장에서 해상수송로 또는 해상교통로 안보 위기는 국가안보 차원의 위기라는 전략적인 인식을 갖는 것이 중요하다. 주요 해상수송로 안보를 위해 한국은 다양한 해양안 보 네트워크나 국가 간 협력체에 참여하는 다자적인 노력이 필요하며, 해상수송 안보에 영향을 미칠 수 있 는 주요 항로나 해상요충지를 위협하는 요인에 대한 최신 정보를 확보하고 이를 바탕으로 효과적인 대응 방 안을 마련하는 것이 필요하다.

Preparations and Characterizations of Nanoporous TiO₂ Films by Sol-Gel Method

장성일,여윤선,정보화,장영욱,노치우,이진국,김미라 한국공업화학회 2007 한국공업화학회 연구논문 초록집 Vol.2007 No.-

Synthesis of Carbonated Soybeanoil using Carbon Dioxide and Nonisocyanate Polyurethane by diamine

장성일,김일 한국고분자학회 2013 한국고분자학회 학술대회 연구논문 초록집 Vol.2013 No.4

개질로 튜브에서의 누출 사고 시 화염에 대한 수치해석

장성일,안준 한국에너지학회 2015 한국에너지공학회 학술발표회 Vol.2015 No.4

Performance of Oil-Separator Adopting Nature-Inspired Surface

장성일,안준,임시형 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

In order to improve a refrigeration system’s energy efficiency, the separation efficiency of its oil separator should be improved. To do so, we turned to nature for inspiration. A Namib Desert beetle collects water in fog by using its skin, which combines hydrophilic and hydrophobic surfaces. Inspired by nature’s design, we applied a surface with oleophilic and oleophobic patterns to an oil separator used in a refrigeration system. In order to make the oil separator, an appropriate design was established using computational fluid dynamics. A cyclone-type oil separator was produced with an oleophobic-treated surface on its lower cup. The efficiency of the treated surface of this oil separator was tested with an open-type experimental setup using an oil mist generator. To obtain conditions similar to those of a refrigeration system in the open-type experimental setup, the oil particle diameter and working fluid pressure were set to yield a Stokes number similar to that of oil particles in the oil separator of the refrigeration system. The oil separator with the treated oleophilic–oleophobic surface improved its oil separation efficiency by 1.67% and its pressure drop by 2.48% compared to a conventional cyclone-type oil separator.

해양안보 개념 연구: 해상수송로 안보 논의를 중심으로

장성일 21세기정치학회 2022 21세기 정치학회보 Vol.32 No.4

This paper aims to conceptualize maritime security by focusing on sea lane security. The strategic and economic significance of sea lane security has vastly increased since the Second World War. Moreover, as international trade grows, the importance of major choke points, such as the Strait of Hormuz, and Malacca, also increases. Sea lane issues can be a national security matter when a state considers a military response to tackle any sea lane security threats. The U.S.-Iran conflict over the Strait of Hormuz in 2019 was a prime example that sea lane security could be national security involving military conflict. However, sea lane security has not received adequate scholarly attention. In that context, this paper attempts to conceptualize sea lane security employing Buzan(1991)'s and Baldwin(1997)’s security studies.

Anastomotic stricture after liver transplantation: It is not Achilles’ heel anymore!

장성일,이동기 소화기인터벤션의학회 2018 Gastrointestinal Intervention Vol.7 No.2

Biliary-tract complications, such as biliary strictures, anastomotic leaks, choledocholithiasis, and biliary casts, can occur after liver transplantation (LT). Of these complications, biliary strictures are regarded as an Achilles’ heel. Recently, treatment of anastomotic biliary stricture (ABS) has transitioned from conventional surgical revision to a nonsurgical treatment modality. Endoscopic serial balloon dilatation and/or multiple plastic stent replacements are highly effective and are now regarded as the first-line treatments. However, if the patient has undergone anastomosis by means of a hepaticojejunostomy, percutaneous treatment is performed. With recent technological advances and the rendezvous method, the clinical success rates of endoscopic and percutaneous ABS treatments have increased, but these methods fail in some patients who have total obstruction of anastomotic stricture. For these patients, magnetic compression anastomosis (MCA) has been suggested as an alternative method. Animal and human studies have demonstrated the safety and efficacy of MCA, and advancements in these nonsurgical methods have increased the clinical success rate of ABS. This review focuses on ABSs that develop after LT and discusses the clinical results of various nonsurgical methods and future directions.

내시경 괄약근 절개술, 풍선을 이용한 담석 제거술, 바스켓을 이용한 담석 제거술

장성일,이동기 대한췌장담도학회(구 대한췌담도학회) 2019 대한췌담도학회지 Vol.24 No.4

담관 담석을 제거하기 위해서는 선택적 담관삽입술(selective cannulation)에 성공한 뒤 내시경 유두괄약근 절개술을 시행하게 된다. 내시경 유두괄약근 절개술은 출혈, 천공, 췌장염 등의 합병증을 발생시킬 수 있다. 이러한 합병증의 발생을 줄이고 시술의 성공률을 높이기 위하여 다양한 형태의 내시경 괄약근 절개기와 절개를 위해 사용되는 전류 발생기가 개발되었다. 또한 절개의 방향과 범위, 절개술에 대한 가이드라인이 정해지고 있다. 괄약근 절개 후 담석의 제거를 위해 사용되는 방법에서 대표적으로 풍선을 이용하는 방법과 바스켓을 이용하는 방법이 있다. 내시경 괄약근 절개술의 기술적 방법을 소개하고, 효과적으로 담석을 제거할 수 있는 대표적인 방법들에 대하여 임상적 적응증과 기술적 방법에 대하여 논하고자 한다. Endoscopic sphincterotomy is performed after selective cannulation to remove the gallstone. Endoscopic sphincterotomy can cause complications such as bleeding, perforation and pancreatitis. Various types of endoscopic sphincter incision method and current generators used for incisions have been developed to reduce the incidence of such complications and increase the success rate of the procedure. In addition, guidelines for the direction and extent of endoscopic sphincterotomy and incision technique are established. The method used for the removal of gallstones after the endoscopic sphincterotomy is a method using a balloon and/or a basket. This review introduces the technical methods of endoscopic sphincterotomy and discusses the clinical indications and technical methods for representative methods of effective gallstone removal.

WMSN의 신뢰성 있는 멀티미디어 데이터 전송을 위한 클러스터 기반 전송 기법

장성일,최승권,김성진 한국엔터테인먼트산업학회 2023 한국엔터테인먼트산업학회논문지 Vol.17 No.7

Recently, the ubiquitous environment has been generalized and IoT has rapidly drawn much public attention. In addition, the performance of the camera has been advanced with the development of low power, subminiature CCD image sensors. With this development, researches have progressed on WMSN(Wireless Multimedia Sensor Network). Unlike WSN(Wireless Sensor Network) which transmits small scalar data, WMSN needs to send massive amounts of multimedia data. Therefore, this paper proposes a cluster based multipath transmission method to reduce the energy loss of sensor nodes in WMSN. The proposed scheme uses clustering and multipath to minimize the energy consumption of sensor nodes. The proposed scheme is compared with conventional LEACH and multi-hop routing schemes through simulation in the view of network lifetime, energy residual, and delay time according to the loads. Simulation results show that the proposed scheme can increase network lifetime by inducting uniform energy consumption. The proposed scheme is an appropriate method for WMSN considering realtime multimedia data service, by reducing the delay time and increasing network lifetime through load balancing and uniformed energy consumption.