폐플라스틱수지와 제지슬럿지의 열분해에 관한 연구

설수덕,왕석주,장성호 동아대학교 환경문제연구소 1994 硏究報告 Vol.17 No.2

The thermal decomposition of the sludge with Poly(acryloniti1e-butadiene-styrene) and Poly(styrene-co-acrylonitrile) were using a thermal analysis techniques in the stream of nitrogen gas of 30ml/min at various heating rates from 4 to 20℃/min. The mathematical, Derivative and Integral method were used to obtained values of activation energy of decomposition reaction. 1. The values of activation energy evaluated by Derivative and Intergral method were consistent with each other very well. 2. The maximum value of heat of decomposition evaluated by DSC method were 10, 120 cal/g at weight ratio of sludge/ABS=20/80 and 10, 500cal/g at weight ratio of sludge/SAN = 20/80. 3. The thermogravimetric trace curve agreed with the theoretical equation.

세계화를 위한 태권도 경기의 발전방향

장석왕 ( Jang Seok Wang ),안용규 ( Yong Kyu Ahn ) 한국체육대학교 체육과학연구소 2013 스포츠사이언스 Vol.31 No.1

이 연구는 세계화를 위한 태권도 경기의 발전방향이라는 주제 아래, 올림픽을 중심으로 그간 태권도 경기의 문제점들로 대두되었던 사회적 시사점을 재검토하고 그 문제점에 대한 실천적 해결방안을 모색하고자 하였다. 특히 이 연구를 통해 태권도가 세계화될 수 있었던 그간의 흔적들을 다시금 회상하고 현재를 반성함으로써 경기화로 인해 다소 훼손되고 변질된 태권도의 본질을 회복하여 태권도 경기에서도 분명 무도성이 존재하고 있음을 시각적으로 나타내고자 하였다. 그 결과, 태권도경기의 문제점들로 대두되었던 그간의 사건들은 최근 들어 새롭게 나타난 문제들이기 보다는 태권도가 경기화되면서 시작되었던 고질적인 문제들이 다른 방식과 형태로 나타나고 있다는 것을 알 수 있었다. 결국 오랜 시간 태권도 경기의 문제점들로 대두되었던 ‘재미없는 경기방식’과 ‘판정시비’가 아직까지 해결되지 않은 채 계속 이어지고 있다는 것이다. 따라서 이제는 똑같이 반복되고, 똑같이 중복되는 해결방안을 제시하는 것에서 잠시 벗어나 새로운 본질적 대안을 찾는 것이 바람직할 것으로 사료된다. 이에 연구자는 스포츠윤리교육을 통한 태권도 경기의 방향성을 새롭게 모색하고자 제언을 한다. 언론을 통해 나타나는 태권도 경기 현장의 부정부패, 페어플레이나 스포츠맨십은 뒤로 한 채 오직 승리만을 위해 수단과 방법을 가리지않은 채 비윤리적인 행위들을 서슴지 않게 행하는 태권도 선수 및 관계자들, 이러한 이들이 만연하는 현 시대에 스포츠윤리교육은 분명 필수적이라 할 수 있다. 스포츠윤리교육, 비록 기존의 제도적 방안이나 대안에 비해 긴 시간을 요하는 새로운 본질적 방안이긴 하지만 훗날 태권도 경기가 올바른 길로 나아가고 보다 이상적으로 태권도의 세계화를 이룩하기 위해서는 반드시 필요한 필수과정이자 교육임에 틀림이 없다. Under the improvement direction of Taekwondo competition for globalization, this study is tried to reconsider social current issues raised from Taekwondo competition with the Olympics as the center and find a practical solution to a problem. Particularly, study intended to regain nature of Taekwondo by reminiscing achievement until now which is globalization``s driving force and reflecting on the present and show visually that Taekwondo competition has chivalry. As a result, issues raised from Taekwondo competition are not new appeared problem. They are chronic problems after the adoption of competition as different method and form. Eventually, ``boring game method`` and ``judgement dispute`` as chronic problem are not resolved until now. Therefore, it is considered that finding fundamental alternative is desirable away from repeated overlapped solution. Researcher suggested to find new direction of Taekwondo competition through training of sports ethics. Now, there are many athlete and participator used any means to get win without respect to corruption, fair play and sportsmanship exposed by media. In this era, training of sports ethics is essential. Traninning of sports ethics, although fundamental alternative requires a lot of time compared to existing institutional way, it is certain that sports ethics is surely mandatory course and education for step on right way and more ideal globalization of Taekwondo.

표면 텍스쳐링 깊이와 간격에 따른 후면 전극 실리콘 태양전지 효율에 미치는 영향

장왕근(Wang Geun Jang),장윤석(Yun-seok Jang),박정일(Jungil Park),박정호(Jungho Pak) 대한전기학회 2011 대한전기학회 학술대회 논문집 Vol.2011 No.7

Characteristics of First Diagnosed Hepatocellular Carcinoma in Liver Cirrhotic Patients during 15 Years : Multicenter Retrospective Study in Daegu-Gyeongbuk Province

( Wang Yong Choi ),( Woo Jin Chung ),( Byoung Kuk Jang ),( Jae Seok Hwang ),( Sang Jin Kim ),( Heon Ju Lee ),( Moon Joo Hwang ),( Young Oh Kweon ),( Won Young Tak ),( Soo Young Park ),( Su Hyun Lee ) 대한간학회 2016 춘·추계 학술대회 (KASL) Vol.2016 No.1

Aims: We aimed to evaluate the characteristics of first diagnosed as hepatocellular carcinoma(HCC) in liver cirrhotic patients in Daegu-Gyeongbuk province in Korea during recent 15 years. Methods: We reviewed retrospectively medical records of 15,716 liver cirrhotic patients of 5 university hospitals with KCD-6 codes in Daegu-Gyeongbuk province from 2000 to 2014. Results: 1. Among 15,716 cirrhotic patients, 1,339 patients(8.5%) diagnosed as HCC. Mean age was 61.2±10.9 years old, men were 975(72.8%) and women were 364(27.2%). The mean time to diagnose as HCC after initial diagnose as cirrhosis was 3.91±2.79 years. 2. Mean annual incidence of HCC was 2.79%. At time of diagnosis, Child-Turcotte-Pugh(CTP) class A was 45.3%, B was 44.8% and C was 9.96%. Mean CTP score was 7.02±1.82. Underlying liver disease were HBV(61.5%), alcohol(19.2%), HCV(9.0%), NAFLD(1.9%) and others. 3. Mean time to diagnose as HCC were 4.01±2.85 years for HBV, 3.48±2.59 years for HCV, 3.96±2.87 years for alcohol, 3.00±1.91 years for NAFLD after initial diagnose as cirrhosis. Mean time to diagnose HCC were 4.98±3.29, 3.47±2.13, 2.28±1.28 years when accessed by five-year intervals (p<0.001), mean CTP score were 7.25±1.87, 6.98±1.80, 6.64±1.67 (p=0.003) 4. There were not significant clinical and laboratory differences in patients diagnosed as HCC within 5 years and beyond 10 years after initial diagnosed as cirrhosis. Conclusions: The time intervals between initial diagnosis as cirrhosis and HCC are significantly reduced. It may caused by active cancer surveillance and advanced diagnostic modalities. Among the various causes of liver cirrhosis, NAFLD has the shortest time interval to diagnoses HCC. So, we need to carefully monitor cirrhotic patients caused by NAFLD.

Nrf2, a Regulator of the Proteasome, Controls Self-Renewal and Pluripotency in Human Embryonic Stem Cells : Nrf2-Proteasome Pathway Controls Stemness in hESCs

Jang, Jiwon,Wang, Yidi,Kim, Hyung-Seok,Lalli, Matthew A.,Kosik, Kenneth S. Wiley (John WileySons) 2014 Stem Cells Vol.32 No.10

<P>Nuclear factor, erythroid 2-like 2 (Nrf2) is a master transcription factor for cellular defense against endogenous and exogenous stresses by regulating expression of many antioxidant and detoxification genes. Here, we show that Nrf2 acts as a key pluripotency gene and a regulator of proteasome activity in human embryonic stem cells (hESCs). Nrf2 expression is highly enriched in hESCs and dramatically decreases upon differentiation. Nrf2 inhibition impairs both the self-renewal ability of hESCs and re-establishment of pluripotency during cellular reprogramming. Nrf2 activation can delay differentiation. During early hESC differentiation, Nrf2 closely colocalizes with OCT4 and NANOG. As an underlying mechanism, our data show that Nrf2 regulates proteasome activity in hESCs partially through proteasome maturation protein (POMP), a proteasome chaperone, which in turn controls the proliferation of self-renewing hESCs, three germ layer differentiation and cellular reprogramming. Even modest proteasome inhibition skews the balance of early differentiation toward mesendoderm at the expense of an ectodermal fate by decreasing the protein level of cyclin D1 and delaying the degradation of OCT4 and NANOG proteins. Taken together, our findings suggest a new potential link between environmental stress and stemness with Nrf2 and the proteasome coordinately positioned as key mediators.</P>

Ultralight and compressible mussel-inspired dopamine-conjugated poly(aspartic acid)/Fe3+-multifunctionalized graphene aerogel

Wang, Bo,Kang, YingBo,Shen, Tian-Zi,Song, Jang-Kun,Park, Ho Seok,Kim, Ji-Heung Springer-Verlag 2018 JOURNAL OF MATERIALS SCIENCE - Vol.53 No.24

Scattering From Two Concentric Thick Conducting Cylindrical Cavity-Backed Apertures

Wang-Sang Lee,Hyeong-Seok Jang,Hyun-Sung Tae,Jong-Won Yu Institute of Electrical and Electronics Engineers 2014 IEEE Transactions on Antennas and Propagation Vol. No.

<P>An exact series solution for scattering and transmitting of two concentric thick conducting cylindrical cavity-backed apertures is formulated by using radial mode matching technique. The scattered and penetrated fields are represented in terms of an infinite series of radial modes. By applying the appropriate boundary conditions, the coefficients of scattered and transmitted fields are obtained. The behavior of resonance features is characterized for variation of structures with another slotted cylinder inside.</P>

High-Performance Electroactive Polymer Actuators Based on Ultrathick Ionic Polymer–Metal Composites with Nanodispersed Metal Electrodes

Wang, Hyuck Sik,Cho, Jaehyun,Song, Dae Seok,Jang, Jong Hyun,Jho, Jae Young,Park, Jong Hyuk American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.26

<P>Ionic polymer metal composites (IPMCs) have been proposed as biomimetic actuators that are operable at low applied voltages. However, the bending strain and generating force of the IPMC actuators have generally exhibited a trade-off relationship, whereas simultaneous enhancement of both the qualities is required for their practical applications. Herein, a significant improvement in both the strain and force of the IPMC actuators is achieved by a facile approach, exploiting thickness-controlled ion-exchange membranes and nanodispersed metal electrodes. To guarantee a large generating force of the IPMC actuators, ultrathick ion-exchange membranes are prepared by stacking pre-extruded Nafion Ems. Metal electrodes with a nanodispersed structure are formed on the membranes via alcohol-assisted electroless plating, which allows increased capacitance and facilitated ion transport. The resulting actuators exhibit greatly enhanced electromechanical properties, including an approximately four times larger strain and two times larger force compared to those of actuators having the conventional structure. Moreover, the ability to lift 16 coins (a weight of 124 g) has been successfully demonstrated using ultrathick IPMC actuators, which shows great promise in realizing artificial muscles.</P>

Numerical Analysis of Effect of Waveform Micropile on Foundation Underpinning During Building Vertical Extension Remodeling

Wang, Cheng-Can(왕성찬),Jang, Youngeun(장영은),Kim, Seok-Jung(김석중),Han, Jin-Tae(한진태) 대한토목학회 2019 대한토목학회논문집 Vol.39 No.2

기존건물의 수직증축시, 추가되는 증축하중을 지지하기 위해서 기초를 보강하는 것은 필수적이다. 일반적으로 기초의 지지력을 증대시키고 침하를 감소시키기 위하여 마이크로파일공법이 널리 활용되고 있다. 본 연구에서는 기존의 마이크로파일에 전단키가 추가된 새로운 형식의 파형마이크로파일을 활용하여 연구를 수행하였다. 유한요소해석법(FEM)을 통해 기초보강시 파형마이크로파일의 하중침하거동과 하중분담율을 평가하였으며, 3가지 길이 다른 일반적인 마이크로파일들의 지지거동과 비교를 통해 보강효과를 확인하였다. 해석 결과, 파형마이크로파일의 지지력과 축강성이 일반 마이크로파일보다 크게 나타났으며, 이는 파형 마이크로파일의 전단키에 의한 효과인 것으로 판단된다. 또한, 수직증축 리모델링 시, 기존하중 대비 20 %의 증축하중이 재하될 때, 파형마이크로파일의 하중분담율이 동일한 길이의 일반 마이크로파일에 비해 약 40 % 증가하였으며, 보강효과는 길이 1~1.5배의 일반적인 마이크로파일보다 우수한 것으로 나타냈다. Micropiles are widely used for foundation underpinning to enhance bearing capacity and reduce settlement of existing foundation. In this study, the main objective is to evaluate underpinning performance of a newly developed micropile called waveform micropile for foundation underpinning during vertical extension. Finite element method (FEM) was used to evaluate the underpinning performance of waveform micropile in terms of load-settlement response of underpinned foundation and load sharing behavior. For comparison, underpinning effects of three conventional micropiles with different lengths were also discussed in this study. Numerical results of load-settlement response for single pile demonstrated that bearing capacity and axial stiffness of waveform micropiles were higher than those of conventional micropiles because of the effect of shear keys of waveform micropiles. When additional loads 20 %, which is according to design loads of the vertical extension, were applied to the underpinned foundation, load sharing capacity of waveform micropile was 40 % higher than conventional micropile at the same size. The waveform micropile also showed better underpinning performance than the conventional micropile of length 1~1.5 times of waveform micropile.

1-port Measurement Method of the Coupling Factor and Receiver <tex> $Q$</tex> for Spatial and State Freedom in Wireless Power Transfer Systems

Jang, Hyeong-Seok,Yu, Jong-Won,Lee, Wang-Sang Institute of Electrical and Electronics Engineers 2016 IEEE Transactions on Antennas and Propagation Vol. No.

<P>For spatial and state freedom in wireless power transfer (WPT) systems, the coupling factor and receiver Q have been estimated, using a loop current flowing into the transmitting coil by 1-port measurement method. Since the power transfer efficiency is related to the coupling factor and the load impedance, it is required to estimate and analyze them. In strongly and loosely coupled regions, the proposed measurement method can evaluate the location and battery states of the receiver by tracking the operating frequency of the transmitter. Compared to the calculated results obtained by conventional 2-port measurements against the k between the transmitting and receiving coils and the receiver Q, the proposed 1-port estimation method for frequency-tuned WPT systems is relatively simple and efficient, and has been experimentally verified.</P>