Pusan National University

About: Pusan National University is a education organization based out in Busan, South Korea. It is known for research contribution in the topics: Catalysis & Population. The organization has 24124 authors who have published 45054 publications receiving 819356 citations. The organization is also known as: Busan National University & Pusan University.

Persistence of Ferroelectricity in BaTiO3 through the Insulator-Metal Transition

Abstract: The ferroelectric BaTiO(3) is a band-gap insulator. Itinerant electrons can be introduced in this material by doping, for example, with oxygen vacancies. Above a critical electron concentration of n(c) approximately 1 x 10(20) cm(-3), BaTiO(3-delta) becomes metallic. This immediately raises a question: Does metallic BaTiO(3-delta) still retain ferroelectricity? One may expect itinerant electrons to destroy ferroelectricity as they screen the long-range Coulomb interactions. We followed the phase transitions in BaTiO(3-delta) as a function of n far into metallic phase. Although their stability range decreases with n, the low-symmetry phases in metallic BaTiO(3-delta) are still retained up to an estimated concentration of n* approximately 1.9 x 10(21) cm(-3). Moreover, it appears that the itinerant electrons partially stabilize the ferroelectric phases in metallic BaTiO(3-delta) by screening strong crystal field perturbations caused by oxygen vacancies.

Prevalence of chronic obstructive pulmonary disease in Korea: The fourth Korean National Health and Nutrition Examination Survey, 2008

Abstract: Background and objective: Because the mortality and social burden associated with COPD is increasing, repeated surveys of the prevalence of COPD have been used to assess risk factors, detect potential patients, and establish early diagnoses and management protocols. We report the prevalence of spirometrically detected COPD in Korea in 2008, using data from the fourth Korean National Health and Nutrition Survey. Methods: Using nationwide stratified random sampling, based on the Korean Statistical Office census, 6840 subjects aged ≥19 years underwent spirometry, which was performed by four trained technicians, during 2008. The place of residence, levels of education and income and smoking status, as well as other results from a COPD survey questionnaire were also assessed. Results: Airflow obstruction (FEV1/FVC < 0.7) was detected in 8.8% of subjects aged ≥19 years (11.6% of men and 5.9% of women) and COPD was detected in 13.4% of subjects aged ≥40 years (19.4% of men and 7.9% of women). Of the 6840 subjects, 27.3% were current smokers and 17.2% were former smokers, and the prevalence of COPD was higher in current and former smokers than in never smokers. Approximately 94% of patients with COPD had mild-to-moderate disease, without apparent symptoms; only 2.4% had been diagnosed by a physician and only 2.1% of patients had been treated. The independent risk factors for COPD were smoking, advanced age and male gender. Conclusions: Although the prevalence of COPD in Korea is high, the disease is underdiagnosed and most COPD patients are under-treated.

Installing kelp forests/seaweed beds for mitigation and adaptation against global warming: Korean Project Overview

Abstract: Ik Kyo Chung1*, Jung Hyun Oak2, Jin Ae Lee3, Jong Ahm Shin4, Jong Gyu Kim5, and Kwang-Seok Park6 Department of Oceanography, Pusan National University, 30, Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea Marine Research Institute, Pusan National University, Busan 609-735, Republic of Korea School of Environmental Science and Engineering, Inje University, Gimhae 621-749, Republic of Korea College of Fisheries and Ocean Sciences, Chonnam National University, Yeosu 550-749, Republic of Korea Response to Climate Change Co., Ltd., Pohang 790-390, Republic of Korea Material Research Division, Research Institute of Industrial Science and Technology, Pohang 790-330, Republic of Korea *Corresponding author: tel: +82 51 51