다공성 탄소층이 코팅된 하이브리드 표면 구조를 갖는 산소 환원 반응용 PtCo 합금 나노 촉매

장정희,모니카 샤르마,성후광,김순표,정남기,Jang, Jeonghee,Sharma, Monika,Sung, Hukwang,Kim, Sunpyo,Jung, Namgee 한국재료학회 2018 한국재료학회지 Vol.28 No.11

During a long-term operation of polymer electrolyte membrane fuel cells(PEMFCs), the fuel cell performance may degrade due to severe agglomeration and dissolution of metal nanoparticles in the cathode. To enhance the electrochemical durability of metal catalysts and to prevent the particle agglomeration in PEMFC operation, this paper proposes a hybrid catalyst structure composed of PtCo alloy nanoparticles encapsulated by porous carbon layers. In the hybrid catalyst structure, the dissolution and migration of PtCo nanoparticles can be effectively prevented by protective carbon shells. In addition, $O_2$ can properly penetrate the porous carbon layers and react on the active Pt surface, which ensures high catalytic activity for the oxygen reduction reaction. Although the hybrid catalyst has a much smaller active surface area due to the carbon encapsulation compared to a commercial Pt catalyst without a carbon layer, it has a much higher specific activity and significantly improved durability than the Pt catalyst. Therefore, it is expected that the designed hybrid catalyst concept will provide an interesting strategy for development of high-performance fuel cell catalysts.

과체중 소아의 부비동염에 대한 한방 치료 2례

장정희,박준홍,Jang, Jung-Hee,Park, Jun-Hong 대한한방안이비인후피부과학회 2016 한방안이비인후피부과학회지 Vol.29 No.2

Objectives : The purpose of this clinical study is to investigate effectiveness of oriental medical treatment for sinusitis in the two overweight children. Methods : This study was performed for two 5-years old of age and overweight (BMI>90th percentile) children with sinusitis who visited the clinic. The symptoms of sinusitis are rhinorrhea, poor sleep due to nasal congestion, cough, sputum. Oriental herb medicines(Kami-Hyunggyeyungyotang and Kami-Cheonggeumganghwatang), moxibustion, nebulizer and aroma nasal spray were treated to two children. The progress of treatment for sinusitis was evaluated through the subjective symptoms and endoscope inspection. Results & Conclusions : After oriental medical treatment, the subjective symptoms and endoscope inspection were improved in all two children. Our results suggested that oriental medical treatment have effective to alleviate the symptoms of sinusitis in overweight children.

ICP/MS를 이용한 축산물의 유해중금속 분석방법 및 숙련도 검증

장정희,김동규,권현정,임채미,손성완,김미경,Jang, Jung-Hee,Kim, Dong-Gyu,Kwon, Hyun-Jeong,Lim, Chae-Mi,Son, Seong-Wan,Kim, MeeKyung 대한수의학회 2012 大韓獸醫學會誌 Vol.52 No.2

The analytical method of trace toxic metals in livestock products was confirmed and validated through certified reference material (CRM) and the international proficiency tests. There are some difficulties to determine low levels of toxic metals in livestock products because of interferences due to the matrix. The recoveries of CRM (NIST 1577c) ranged from 73.9 to 119% for lead and from 86.4 to 111% for cadmium in bovine liver. The international proficiency tests were carried out with the milk powder and cocoa powder samples including metals provided by Food Analysis Performance Assessment Scheme (FAPAS$^{(R)}$, UK). The test samples were prepared by microwave digestion using solution of $HNO_3:H_2O_2:H_2O$ (v/v/v = 5 : 2 : 4) and analyzed by ICP/MS. The analytical result of cadmium in milk powder was $121{\mu}g/kg$ with -0.3 of the z-score compared to the assigned value of $131{\mu}g/kg$ by FAPAS$^{(R)}$. The analytical results of lead and cadmium in cocoa powder were $29.2{\mu}g/kg$ and $97.6{\mu}g/kg$, respectively, which satisfied the assigned values of $34.2{\mu}g/kg$ for lead and $126{\mu}g/kg$ for cadmium by FAPAS$^{(R)}$. It is verified that the analytical method is accurate and reliable to determine trace lead and cadmium in livestock products by microwave digestion and ICP/MS.

2008-2009년 국내 폐사 야생조류 및 동물 체내의 잔류농약 분석

장정희,봉영훈,김동규,김미경,정갑수,손성완,Jang, Jung-Hee,Bong, Young-Hoon,Kim, Dong-Gyu,Kim, MeeKyung,Chung, Gab-Soo,Son, Seong-Wan 대한수의학회 2010 大韓獸醫學會誌 Vol.50 No.3

Pesticides are useful to eliminate harmful insects and grow crops however, misuse and abuse of pesticides may cause a death of wild birds, livestock, and companion animals. We analyzed residual pesticides in the ingesta and tissues from the dead wild birds, livestock, and companion animals which were suspected pesticide poisoning based on the diagnosis of the Animal Disease Diagnostic Center of National Veterinary Research and Quarantine Service (NVRQS). The samples were primarily brought to NVRQS from local communities and veterinary diagnostic laboratories. The 231 suspicious samples of pesticide poisoning based on the necropsy were analyzed by GC/NPD, GC/FPD, GC/ECD, or GC/MSD in 2008 and 2009. Pesticides were identified from the 55 samples of total 143 samples analyzed in 2008 and from the 34 samples of total 88 samples analyzed in 2009. The pesticide identification rates in 2008 were higher than the rates in 2009. It may have relevance to the increased samples with the outbreak of avian influenza in 2008 in Korea. The concentrations of pesticides found in the dead animals varied and exceeded the respective $LD_{50}$ of pesticides in many cases. Monochrotophos, phosphamidon, and methomyl were the most common pesticides found and those pesticides are high rank sales in Korea. The cause of pesticide poisoning in animal is assuming a misuse and an abuse of commonly used pesticides in Korea.

H₂O₂ 촉매 전환에 의해 생성된 건식산화제를 이용한 NO 산화에 관한 연구

장정희,한기보,Jang, Jung Hee,Han, Gi Bo 한국응용과학기술학회 2016 한국응용과학기술학회지 Vol.33 No.1

본 연구에서는 촉매 상 $H_2O_2$ 전환에 의해 건식산화제가 생성되었으며, 이를 이용한 NO 산화 공정에 대한 연구를 진행하였다. 건식산화제를 생성하기 위한 $H_2O_2$ 촉매 전환에 관한 실험을 수행한 결과, Mn계 촉매의 성능이 가장 우수하였으며, 이를 통해 생성된 건식산화제를 NO 산화공정에 주입하여 다양한 운전조건에서 NO 산화특성을 조사하였다. 그 결과, $H_2O_2$ 주입량, 산화반응온도, 그리고 공간속도가 NO 산화율에 크게 영향을 미치는 것을 확인하였다. 그리고, 산화반응온도와 $H_2O_2$ 주입량이 증가할수록 NO 산화효율이 증가하였으며, 공간속도가 증가할수록 NO 산화효율이 감소하였다. In this study, the NO oxidation using dry oxidant produced by catalytic $H_2O_2$ conversion was conducted. It was shown that Mn-based $Fe_2O_3$ support catalyst has the best performance in the catalytic $H_2O_2$ conversion and its combined-NO oxidation. The reaction characteristics of NO oxidation was investigated by the various operation conditions such as $H_2O_2$ amount, oxidation temperature and space velocity. As a results, the oxidation efficiency of NO greatly depends on the oxidation reaction temperature, $H_2O_2$ amount and space velocity. The performance of NO oxidation was increased with increasing the oxidation temperature and $H_2O_2$ amount. Also, the performance of NO oxidation was decreased with increasing the space velocity.

일반강의식 수업에서 교수·학습 방법에 관한 연구

장정희,서종진,Jang, Cheong Hee,Seo, Jong Jin 한국학교수학회 2021 韓國學校數學會論文集 Vol.24 No.3

과거에서 현재까지 교양 수학 수업에서 교육 환경의 변화를 추구하였으나 현재에도 대학 교육 여건으로 말미암아 일반강의식 수업이 이루어지고 있다. 이에 본 연구에서는 일반강의식 수업에서 학생들에게 도움이 되는 교수·학습 방법을 찾고자 하였다. 개별 과제와 피드백 및 수업 내용을 필기하는 방법이 동일 과제와 피드백을 제공하는 방법이나 동일 과제와 피드백 제공 및 수업 내용을 필기하도록 하는 방법보다는 학생들의 학습에 도움이 되는 것으로 나타났다. From the past to the present, general mathematics classes have pursued changes in the educational environment. However, due to the actual college education conditions, general lecture classes are taking place. In this study, we wanted to find teaching and learning methods that would help students in general lecture classes. As a result, one group that took notes about class content and provided feedback on individual tasks was more effective in math achievement than the group that provided feedback on the same task. In addition, one group who took notes on class content and provided feedback on individual assignments was more effective in math achievement than the group who took notes on class content and provided feedback on the same task.

농업기술 - 겨울철 인기 만점 포인세티아 재배관리요령

장정희,Jang, Jeong-Hui 전국농업기술자협회 2009 농업기술회보 Vol.46 No.1

크리스마스를 상징하는 화려한 포인세티아는 겨울철의 대표적인 분화이다. 포인세티아 수요는 매년 괄목할 만한 성장을 하여 겨울 꽃시장의 주요 상품으로서 자리 매김을 하고 있지만 그동안 외국 품종에 대한 높은 로열티 지불로 화훼농가 경영에 큰 부담이 되었다. 농촌진흥청에서는 포인세티아 신품종을 육성, 보급하여 로열티 경감과 화훼농가의 안정적인 소득 증대를 위해 노력하고 있다. 포인세티아는 단일성 식물로 보통 자연일장이 줄어드는 10월부터 이듬해 3월 중순까지 꽃눈을 형성한다. 이 시기는 일장단축과 함께 온도도 영향을 미치며 일장조절에 의한 연중출하가 가능하다. 겨울철 출하를 목표로 재배중인 포인세티아는 적정 온도유지, 환기에 의한 습도관리, 병해충 방제 등 환경관리에 특별히 유의해야 한다.

대한제국기 아동 독물의 탄생과 아동관의 다변화 양상

장정희(Jang Jeonghee) 한국아동청소년문학학회 2016 아동청소년문학연구 Vol.- No.18

This study conducts a comprehensive examination into the aspects of changing viewpoints of children exhibited by children"s books during the Korean Empire period. In the late Joseon Dynasty when Silhak(practical science) slowly began spreading, it was dominated by Confucian viewpoints of children where it was taught to reach adulthood by learning ‘Cheon(天)’ and ‘Dao(道).’ And this study points out that proliferation of Hangul and children’s tendency favoring books written in Korean were the pivotal elements for the formation of the viewpoints of children. Modern children’s literature in Korea is very close to ‘Korean Literature Awareness(國文意識).’ Especially, this study highly valued the Korean Empire period when the establishment of modern school was legislated including the ‘Royal Doctrine for Building State by Education(敎育立國詔書)’ by King Gojong. And many children"s textbooks published during the time were also closely looked into. At the time, Confucian viewpoints of children still remained, which led children"s book under ‘Elementary Learning’ to be the basic literature; and the concepts of ‘State(國家)’ such as ‘Gaeguk(開國)’ and ‘Independent State(獨立國)’ were enhanced. After sovereignty was taken away, the viewpoints of children also went through radical changes; and the children in the State without sovereignty emerged as a principal subject of enlightenment replacing the ‘State(國).’ It means that the declaration, “Let the young generation to be the State of Daehan,” turned feasible. And individual characteristics of children were also emphasized. During the Korean Empire period, a variety of books to read began to be developed; and while Confucian viewpoints of children still prolonged, the ‘children’ as principal subjects of modernity became more important.

다이캐스팅 모바일 기기의 기공결함 감소를 위한 유동구조 설계

장정희(Jeong Hui Jang),김준형(Jun Hyung Kim),한철호(Chul Ho Han) 한국기계가공학회 2021 한국기계가공학회지 Vol.20 No.2

Usually, the die-cast components used in small mobile devices require finishing processes, such as computer numerically controlled coating. In such cases, porosity is the most important defect. The shape of the molten aluminum that passes through the runner and gate in a mold is the one of the factors that influences gas porosity. To define the spurt index, which numerically indicates the shape of molten aluminum after the gate, Reynolds number and Ohnesorge number are used. Before die fabrication, computer-aided engineering analysis is performed to optimize the filling pattern. Finally, X-ray and surface inspection are performed after casting and machining to evaluate how the spurt index affects porosity and other product parameters. Based on the results obtained herein, a new gating system design process is suggested.

관리형매립지 포플러의 식재 지반별 토양 이화학적 특성

장정희 ( Junghee Jang ) 한국폐기물자원순환학회 2021 한국폐기물자원순환학회 추계학술발표논문집 Vol.2021 No.-