Crystal Structures of Fluoropolymers and Their Piezoelectric Properties: A Molecular Simulation Approach

June Huh(허준),박철민 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.2

Crystal structures of fluoropolymers (FPs) and their properties were investigated using molecular simulations, focusing on the relation between structure (chemical structure of FP monomers and crystal structure) and piezoelectric property for the series of FPs including polyvinylidene fluoride (PVDF) and its variants. For molecular simulations, Monte Carlo (MC) simulations and density functional perturbation theory (DFPT) were employed to predict the crystal structure and piezoelectric properties, respectively, and the sampling of FPs in the molecular space was carried out by mutating PVDF using dynamic Monte Carlo sampling.

그래포에픽택시에 의한 블록 공중합체 라멜라 유도 자기조립의 동력학

허준(June Huh) 한국고분자학회 2014 고분자 과학과 기술 Vol.25 No.6

Self-Assembly of Comb Copolymers

June Huh(허준) 한국고분자학회 2021 한국고분자학회 학술대회 연구논문 초록집 Vol.46 No.1

The self-assembly behaviors of various comb copolymers are investigated by using Monte Carlo simulations, random phase approximation (RPA), and self-consistent field theoretic (SCFT) simulations. We consider three kinds of comb copolymer systems having different copolymer constitutions: comb copolymer with an alternating sequence of A and B side chains (a-CC); comb copolymer with blocky sequence of A and B side chains (b-CC); comb copolymer with side chains of A-B diblock chains (core-shell type side chain) (c-CC). A particular focus in this simulation study will be placed on the molecular packing of comb copolymers in their ordered structures, which will interpret various structural and transition characteristics in bulk and in thin films.

고분자 자기조립 구조의 전산 모사

허준(June Huh),조원호(Won Ho Jo) 한국고분자학회 2006 폴리머 Vol.30 No.6

거대 간 종괴와 심방 중격 결손을 동반한 Abernethy 기형 2형 1예

이해정,이지현,허준,강이석,이흥재,서연림,유소영,최연호,Lee, Hae-Jeong,Lee, Jee-Hyun,Huh, June,Kang, I-Seok,Lee, Heung-Jae,Suh, Yeon-Lim,Yoo, So-Young,Choe, Yon-Ho 대한소아소화기영양학회 2008 Pediatric gastroenterology, hepatology & nutrition Vol.11 No.1

저자들은 간의 거대 종괴와 심방 중격 결손으로 수술을 받았던 환아에서 복부 CT와 간 조직 검사를 통해 확인된 Abernethy 기형 2형 1예를 경험하였기에 문헌 고찰과 함께 보고하는 바이다. Extrahepatic portosystemic shunts, known as Abernethy malformations, were first reported by John Abernethy in 1793. They are classified into two types: Type I refers to a congenital absence of the portal vein and Type II refers to a shunt involving a side-to-side anastomosis with reduced portal blood flow into the liver parenchyma. This malformation is so rare that less than 100 cases have been reported in the medical literature. We report the case of a 13-month-old boy who had a congenital extrahepatic portocaval shunt with a hypoplastic portal vein. This case was complicated with an atrial septal defect and a large hyperplastic nodule in the liver. The patient was diagnosed with a Type II Abernethy malformation. We planned on surgical occlusion of the extrahepatic portocaval shunt. However, six months later, the patient had a sudden onset of a fever of unknown origin and developed hepatic encephalopathy. Although he underwent a liver transplantation, he died of acute hepatic failure.

Nano Clay를 이용한 난연성 Polyolefin Compound의 제조 및 특성에 관한 연구

강두환 ( Doo Whan Kang ),허준 ( June Huh ) 한국유화학회 2003 한국응용과학기술학회지 Vol.20 No.2

N/A Fireproofing polyolefin nanocomposite for the application of power distributingpanel wes prepared by compounding linear linear low density polyethylene(LLDPE),decabromodiphenyl oxide (DBDPO), Sb_2O_3 as flame retardant agents, and modified nano clay as filler. The optimized formulation ratio of compounds to prepare the fireproofing polyolefin nanocomposite ws obtained The flame retardant properties for nanocomposite prepared by compounding 22.5 phr of nano clay and 18 phr of DBDPO based on 100 phr of LLDPE were shown that the combustion time, 10∼18 s, combustion distance, 12∼15 mm and non-melt dropping characteristics. In particular, the content of DBDPO in nanocomposite could be dereased to 18 phr from 40 phr DBDPO for fireproofing composite containing 30 phr of caly. The electrical properties measured from tracking test, had an excellent antitracking properties by not showing the phenomenon of leakage current and sparking.

기관지폐이형성증 환아에서 폐고혈압의 임상 경과 및 예후에 관한 분석: 단일 기관 연구

김지현 ( Ji Hyun Kim ),허준 ( June Huh ),강이석 ( I Seok Kang ),이상일 ( Sang Il Lee ),이흥재 ( Heung Jae Lee ),안강모 ( Kang Mo Ahn ) 대한소아알레르기호흡기학회(구 대한소아알레르기 및 호흡기학회) 2008 소아알레르기 및 호흡기학회지 Vol.18 No.3

목적: 최근 기관지폐이형성증 환아가 늘면서 이로 인한 이차성 폐고혈압도 증가할 가능성이 있으나, 이에 대한 연구는 아직 부족하다. 따라서 폐고혈압이 동반된 기관지폐이형성증 환아의 임상 경과와 예후를 알고자 하였다. 방법: 삼성서울병원 신생아중환자실에 입원한 미숙아 중 기관지폐이형성증이 발생한 환아 240명을 대상으로 의무 기록을 후향적으로 분석하였다. 폐고혈압 동반 여부에 따라 두 군으로 나누고 사망률, 이환율 등의 임상 경과를 비교하고, 폐고혈압 발생군에서 예후를 예측할 수 있는 인자가 있는지 분석하였다. 결과: 총 240명의 기관지폐이형성증 환아 중 19명(7.9%)에서 폐고혈압이 발생하였다. 폐고혈압 발생군은 미발생군에 비해 여아와 부당경량아의 비율이 더 높았고, 기관지폐이형성증의 중증도가 더 높았으며, 신생아중환자실에서 인공환기요법을 시행한 기간이 더 길고, 최대 최고흡기압이 더 높았다. 폐고혈압 발생군에서 사망률이 더 높았고, 신생아중환자실 퇴원 이후 더 오랫동안 산소 치료가 필요하였다. 또한 호흡기 질환으로 인한 재입원 횟수가 더 많았으며, 재입원시 소아중환자실에서 치료받거나 인공환기요법을 시행받는 빈도가 더 높았다. 폐고혈압이 동반된 환자에서 사망과 관련된 예후를 예측할 수 있는 인자는 없었다. 결론: 폐고혈압은 기관지폐이형성증의 치명적이고 심각한 합병증으로, 임상적 특성이나 위험 인자로 예측하기 어려우므로, 특히 여아와 출생 체중 500 g 미만, 부당경량아, 장기간 인공환기요법을 받았거나 중증 기관지폐이형성증을 가진 미숙아에서는 폐고혈압의 발생 가능성에 대하여 상기해야 한다. Purpose: The aim of our study was to determine the clinical course and the prognosis of pulmonary hypertension (PHT) with bronchopulmonary dysplasia (BPD). Methods: Two hundred forty infants who were admitted to the neonatal intensive care unit (NICU) of Samsung Medical Center from January 2002 to December 2006 and were diagnosed with BPD were enrolled in this study. We investigated their medical records retrospectively to investigate any difference between BPD with PHT group and BPD without PHT group in clinical characteristics, mortality and morbidity. Results: Nineteen (7.9%) of the 240 patients with BPD developed PHT. The ratio of females to males was 2.8: 1. The severity of BPD, the small birth weight for gestational age, the duration of mechanical ventilation and the maximal peak inspiratory pressure were significantly associated with the development of PHT. (P=0.000, P=0.007 and P=0.000, respectively) The mortality was higher in the BPD with PHT group than in the BPD without PHT group. (P=0.000) BPD with PHT group required longer duration of oxygen therapy and had more rehospitalization for respiratory illness than the others. (P=0.014) More patients were admitted to the pediatric intensive care unit and received mechanical ventilation therapy in the BPD with PHT group. (P=0.001 and P=0.020, respectively) Conclusions: PHT is one of the causes associated with high mortality and morbidity in BPD patients. Therefore, the physician should be alert to the development of PHT in premature infants with severe BPD, especially if the baby is female, less than 500 g of birth weight, small for gestational age, or supported by mechanical ventilation for a prolonged duration. [Pediatr Allergy Respir Dis(Korea) 2008;18: 243-252]

고분자 재생기술 근적외선 분광법을 이용한 폐플라스틱 분리선별기술개발

최형기 ( Hyeong Ki Choi ),이용무 ( Yong Moo Lee ),허준 ( June Huh ),강두환 ( Doo Whan Kang ),서강일 ( Kang Il Seo ) 한국공업화학회 2007 공업화학전망 Vol.10 No.3

광개시제 종류에 따른 유기 박막의 경화 특성과 플렉서블 디스플레이 봉지 소재로의 적용성 분석

오준기(Junki Oh),김소현(So Hyun Kim),정인조(Kevin Injoe Jung),허준(June Huh),정현욱(Hyun Wook Jung),방준하(Joona Bang) 한국고분자학회 2020 폴리머 Vol.44 No.6

플렉서블 디스플레이에 적용할 수 있는 유기 박막 개발을 위해 광경화성 소재에 대한 특성화를 진행하였다. 광경화에 필수적인 요소인 광개시제는 광 조사 시 분해되며 라디칼을 생성하는 Type-1 개시제와 분해없이 라디칼을 생성하는 Type-2 개시제 유형으로 구분된다. Type-2 개시제는 미반응물에 의한 아웃가스 배출이 거의 없는 특성으로 인해 디스플레이 봉지 유기층 제조에 결정적인 역할을 할 수 있다. 본 연구에서는 봉지층에 사용될 유기 코팅액의 경화물성을 최적화하기 위해 Type-1, Type-2 개시제에 의한 실시간 가교 물성을 비교 분석하였다. 잉크젯 코팅공정으로의 적용 가능성을 평가하기 위하여 경화 이전 코팅액의 점도와 표면 장력 등과 같은 기본 유동 물성을 측정하였다. 또한 경화된 박막 필름의 투과율, 굴절률 등과 같은 광학적 물성들을 분석하였다. 다양한 실험 결과로부터 아웃가스 저배출 성능이 뛰어난 Type-2 개시제가 유기막의 핵심 성분으로 디스플레이 봉지 기술을 개발하는데 매우 유용함을 확인하였다. In this work, we examined photocurable materials for organic layers that can be used as an encapsulation layer in flexible displays. Photo-initiators, which are essential for UV-crosslinking, can be classified into two categories: Type-1 initiators that produce free radicals through the cleavage reaction caused by UV irradiation and Type-2 initiators that generate free radicals without the cleavage reaction. Type-2 initiators are more desirable for the encapsulation organic layer of the flexible display due to the low outgassing of unreacted components. To optimize the curing properties of organic coatings, the effect of initiator type on the real-time crosslinking behaviors were mainly scrutinized. The flow properties of pre-cured coatings such as shear viscosity and surface tension were also measured to evaluate the applicability in the inkjet coating process, and transmittance and refractive index were analyzed for the optical properties of cured thin films. As a result, it was found that Type-2 initiators, exerting the intrinsic low outgassing performance, are more advantageous in developing the display encapsulation technology as a key component in the organic layer.

CHARGE 증후군 환자에서 호흡기 문제에 관한 분석: 단일 기관 연구

송상미 ( Sangmi Song ),박미란 ( Mi Ran Park ),김지현 ( Jihyun Kim ),최연아 ( Youn Ah Choi ),허준 ( Jinyoung Song ),강이석 ( June Huh ),정만기 ( I Seok Kang ),정한신 ( Man Ki Chung ),손영익 ( Han Sin Jeong ),안강모 ( Young Ik Son 대한천식알레르기학회 2014 Allergy Asthma & Respiratory Disease Vol.2 No.1

Purpose: CHARGE syndrome consists of multiple malformation including coloboma, heart defect, choanal atresia, growth or developmental retardation, genital anomalies, and ear anomalies. The aim of this study was to evaluate the respiratory problems in children with CHARGE syndrome. Methods: Out of 9 patients with CHARGE syndrome, medical records from 8 patients showing respiratory distress or respiratory failure were retrospectively reviewed. We investigated the causes of respiratory problems by physical examination, endoscopy, echocardiogram, computed tomography, rigid bronchoscopy, swallowing test, and 24-hour impedence monitoring. esults: Five patients required endotracheal intubation soon after birth due to bilateral choanal atresia (n=2) and congenital heart diseases (n=3). Three patients were intubated within a month because of surgery for complex heart diseases (n=2) or recurrent apnea (n=1). Tracheostomy was performed in 3 patients who showed primary or secondary subglottic stenosis. Among 8 patients who had aspiration or respiratory distress after feeding, cricopharyngeal incoordination and gastroesophageal reflux disease were found in 7 and 2 children, respectively. One patient died of aspiration during oral feeding. Conclusion: Patients with CHARGE syndrome manifest respiratory distress or failure due to various causes including congenital anomaly in the airway, cardiac anomaly, neurologic or gastrointestinal problems. Therefore, pediatricians should be alert to the respiratory symptoms and signs in CHARGE syndrome and take active intervention from the birth to improve their long-term prognosis. (Allergy Asthma Respir Dis 2014;2:70-74)