Highly Thermal Conductive and Stretchable Composite for Thermal Dissipation

Dalim Leang,Changgu Lee 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.11

Flexible electronic devices require thermal dissipating materials possessing high thermal conductivity and stretchability. Filler-reinforced polymer composites have drawn considerable attention due to their advantageous stretchability and thermal conductivity. However, the demand for composites that possess both properties remains challenging. In this study, carbon fiber (CF)/carbon nanotube (CNT)-reinforced composite film that possesses both high in-plane thermal conductivity and stretchability was fabricated using Float Assembly method. This method enables carbon fibers to align in a specific direction, reducing thermal resistance between fibers, leading to high anisotropic thermal conductivity. As a result, a high in-plane thermal conductivity of approximately 20 W/m.K at 50% loading, with strain exceeding 60%, was successfully produced. Furthermore, the thickness of the composite film was measured to be less than 1 millimeter (approximately 200 micrometers), aligning with the ongoing trend of miniaturization in electronic devices. This composite will find its application in the thermal management of flexible devices.

영상변형:얼굴 스케치와 사진간의 증명가능한 영상변형 네트워크

숭타이리엥 ( Thai-leang Sung ),이효종 ( Hyo-jong Lee ) 한국정보처리학회 2019 한국정보처리학회 학술대회논문집 Vol.26 No.1

In this paper, we propose a verifiable image transformation networks to transform face sketch to photo and vice versa. Face sketch-photo is very popular in computer vision applications. It has been used in some specific official departments such as law enforcement and digital entertainment. There are several existing face sketch-photo synthesizing methods that use feed-forward convolution neural networks; however, it is hard to assure whether the results of the methods are well mapped by depending only on loss values or accuracy results alone. In our approach, we use two Resnet encoder-decoder networks as image transformation networks. One is for sketch-photo and another is for photo-sketch. They depend on each other to verify their output results during training. For example, using photo-sketch transformation networks to verify the photo result of sketch-photo by inputting the result to the photosketch transformation networks and find loss between the reversed transformed result with ground-truth sketch. Likely, we can verify the sketch result as well in a reverse way. Our networks contain two loss functions such as sketch-photo loss and photo-sketch loss for the basic transformation stages and the other two-loss functions such as sketch-photo verification loss and photo-sketch verification loss for the verification stages. Our experiment results on CUFS dataset achieve reasonable results compared with the state-of-the-art approaches.

Prediction of Vertical Pressure in a Trench As Influenced by Soil Arching

홍원표,Meng Leang Bov,김현명 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.7

A series of model tests was performed to investigate the effect of soil arching on the vertical pressure imposed on the bottom of a trench during backfilling. Soil arching can reduce some portion of the vertical pressure generated by the overburdening soil weight in a trench. To determine theoretically the vertical pressure based on the available formula, two unknown factors must be found: (1) the horizontal stress acting on the trench wall, which is related to the lateral earth pressure coefficient, and (2) the wall friction mobilized between the fill soil and the trench wall. However, appropriately determining those two factors is extremely difficult. Therefore, this paper proposes a novel method using the soil arching coefficient to capture the vertical pressure. The soil arching coefficient is here defined as a constant value that depends on neither the internal friction angle of the backfill soil nor the width of the trench. Qualitative and quantitative tests show good agreement between the vertical pressure predicted by the proposed method and experimental data measured in both laboratory and field tests.

黃酸-蓚酸 混酸浴 中에서의 알루미늄板의 陽極酸化

張學良,金敎秀 영남대학교 공업기술연구소 1973 연구보고 Vol.1 No.1

黃酸 或은 修酸 單獨浴 中에서의 알루미늄板의 陽極酸化에 關한 特許 或은 硏究는 많이 發表되고 있다. 그러나, 이들의 混酸浴에 對하여서는 거의 發表가 없으므로 著者들은 이들 混酸浴 中에서 여러 條件下에서의 알루미늄板의 陽極酸化時 生成한 酸化皮膜의 性質, 溶出한 Al의 量 및 coating ratio 等을 浴溫 20∼35℃에서 各 單獨浴을 使用한 경우와 相互 比較 檢討하였던 바 그의 모든 點에서 單獨浴의 경우보다 그 成績이 좋았다. The properties of aluminun oxide film formed, the almount of dissolved Al, the coating ratio, etc, in the process of anodic oxidation of aluminum plate in a H₂SO₄-H₂C₂O₄mixed acid bath were compared with those obtained in either H₂SO₄or H₂C₂O₄simple bath. Consequently, in the mixed acid bath, it was revealed that 1)more thick film of the oxide was formed than formed in the H₂SO₄bath; 2) the abrasion and orrosion resistance of the film formed were inferior to those formed in the H₂C₂O₄bath, but much superior to those formed in the H₂SO₄bath; 3) the amount of dissolved Al was much smaller than that in the H₂SO₄bath, but a little greater than that in the H₂C₂O₄bath; 4) the coating ratio was the same as that in the H₂C₂O₄bath; 5) the dissolution of Al was inhibited than that in the H₂SO₄bath; and 6) in particular, the properties of the oxide formed at higher temperature was better compared to those formed in the H₂SO₄bath.

A low cost miniature PZT amplifier for wirelessactive structural health monitoring

Claudio Olmi,Gangbing Song,Leang-San Shieh,Yi-Lung Mo 국제구조공학회 2011 Smart Structures and Systems, An International Jou Vol.7 No.5

Piezo-based active structural health monitoring (SHM) requires amplifiers specifically designed for capacitive loads. Moreover, with the increase in number of applications of wireless SHM systems, energy efficiency and cost reduction for this type of amplifiers is becoming a requirement. General lab grade amplifiers are big and costly, and not built for outdoor environments. Although some piezoceramic power amplifiers are available in the market, none of them are specifically targeting the wireless constraints and low power requirements. In this paper, a piezoceramic transducer amplifier for wireless active SHM systems has been designed. Power requirements are met by two digital On/Off switches that set the amplifier in a standby state when not in use. It provides a stable ±180 Volts output with a bandwidth of 7k Hz using a single 12 V battery. Additionally, both voltage and current outputs are provided for feedback control, impedance check, or actuator damage verification. Vibration control tests of an aluminum beam were conducted in the University of Houston lab, while wireless active SHM tests of a wind turbine blade were performed in the Harbin Institute of Technology wind tunnel. The results showed that the developed amplifier provided equivalent results to commercial solutions in suppressing structural vibrations, and that it allows researchers to perform active wireless SHM on moving objects with no power wires from the grid.

Manufacturing Data Analysis Method Using Curve Deviation

Doung Chankhihort(동 키호트),Leang Bunrong(레옹 분롱),Eath Manith(이얼 마닏),Vuthea Chheang(치잉 부띠에),Ga-Ae Ryu(류가애),Kwan-Hee Yoo(류관희) 한국컴퓨터그래픽스학회 2017 한국컴퓨터그래픽스학회 학술대회 Vol.2017 No.7

The Role of Matrix Metalloproteinase-9 in Alcoholic Fatty Liver Disease

( Yu-hsiang Liao ),( Chien Huang ),( Leang-shin Wu ),( De-shien Jong ),( Chih-hsien Chiu ),( Yi-fan Jiang ) 대한간학회 2021 춘·추계 학술대회 (KASL) Vol.2021 No.1

A low cost miniature PZT amplifier for wireless active structural health monitoring

Olmi, Claudio,Song, Gangbing,Shieh, Leang-San,Mo, Yi-Lung Techno-Press 2011 Smart Structures and Systems, An International Jou Vol.7 No.5

Piezo-based active structural health monitoring (SHM) requires amplifiers specifically designed for capacitive loads. Moreover, with the increase in number of applications of wireless SHM systems, energy efficiency and cost reduction for this type of amplifiers is becoming a requirement. General lab grade amplifiers are big and costly, and not built for outdoor environments. Although some piezoceramic power amplifiers are available in the market, none of them are specifically targeting the wireless constraints and low power requirements. In this paper, a piezoceramic transducer amplifier for wireless active SHM systems has been designed. Power requirements are met by two digital On/Off switches that set the amplifier in a standby state when not in use. It provides a stable ${\pm}180$ Volts output with a bandwidth of 7k Hz using a single 12 V battery. Additionally, both voltage and current outputs are provided for feedback control, impedance check, or actuator damage verification. Vibration control tests of an aluminum beam were conducted in the University of Houston lab, while wireless active SHM tests of a wind turbine blade were performed in the Harbin Institute of Technology wind tunnel. The results showed that the developed amplifier provided equivalent results to commercial solutions in suppressing structural vibrations, and that it allows researchers to perform active wireless SHM on moving objects with no power wires from the grid.

골반 초음파 감시 하에 16 Gauge Angioneedle™을 사용하여 치료적 더글라스와 천자를 시행하여 치유된 복강 내 출혈 1예

김미영,이해혁,유애리,박정희,이임순,정수호,레앙소팔,배동한,김태희,이권해 순천향의학연구소 2008 Journal of Soonchunhyang Medical Science Vol.14 No.1

Culdocentesis is a procedure that checks for abnormal Quid in the space just behind the vagina (cul-de-sac). First, a pelvic examination is done. Then, after exposing the postehor vaginal fonix with a bivalve vaginal speculum the posterior lip of the cervix is grasped with a tenaculum. The cul-de-sac is then entered through the postehor vaginal wall with an 18-20 gauge needle with a syringe inserted. As the cul-de-sac is entered, suction is applied, and the intraperitoneal contents are aspirated. In the recent past, culdocentesis was commonly used in the evaluation of a vahety of common intraperitoneal conditions, principally, the hemorrhage associated with ectopic gestations and ruptured ovarian cysts the presence and/or drainage of purulent associated with pelvic inGammatory disease, and as a screening procedure to facilitate early diagnosis of ovarian neoplasms. Usually 16-18 gauge needle with a syhnge attached was used for culdocentesis. But we have experienced a case of therapeutic culdocentesis with 16 gauge angioneedle in patient of hemoperitoneum. So, report it with a bhef review of literature.

A universal ultrasound diagnostic system developed to support urology and coloproctological applications

김정석,Jong Gun Lee,Jae Hyeok Choi,Bong Hyo Han,Se Leang Yoon,Ho Jung,Tai Kyong Song,Jae Young Lee 대한의용생체공학회 2019 Biomedical Engineering Letters (BMEL) Vol.9 No.1

In this study, we sought to describe a novel imaging apparatus that is lightweight, inexpensive, and highly eff ective for use incolorectal diagnostic and treatment settings. Typical probes for use in colorectal ultrasonic imaging applications are developedfor surgeons to diagnose and stage rectal tumors and image the rectum and anus. Here we outline a new technique and use itfor colorectal imaging in an animal. This technique involves use of an ultrasound array module positioned along the axis ofrotation such that improved rotation is possible. This module is in the shape of a linear rod with a rotary linear componentthat allows for emission of focused ultrasonic echo signals from a linear section of the probe. The usability of the transducerand rectal image quality are satisfactory in a porcine model with the technique proposed here, axial/lateral resolution as0.96/2.24 mm with 6 dB applied through the contour map using the point spread function. When compared to currentlyavailable methods, this technique provides superior diagnostic 3D volumetric image quality with reduced acquisition time. Given this, the ultrasound device proposed here may prove a viable and preferable method to those currently available forurology and colorectal imaging applications.