http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
당뇨병 환자에서 Power Spectrum Analysis 를 이용한 자율신경계 이상의 검정
이두하(Du Ha Lee),황형기(Hyoung Ki Hwang),이형우(Hyoung Woo Lee),김영조(Young Jo Kim),심봉섭(Bong Sup Shim),이현우(Hyun Woo Lee),신동구(Dong Ku Shin),이상학(Sang Hak Lee),이준하(Jun Ha Lee) 대한내과학회 1991 대한내과학회지 Vol.41 No.5
In order to assess the autonomic nervous system activity in normal subjects and in diabetic patients affected by different degrees of diabetic autonomic neuropathy, we applied autoregressive power spectral analysis to 35 diabetic patients and 15 normal controls. This analysis was then compared to conventional methods by CAN score tests. Each subject was placed on a bed and connected to electro-cardiographic electrodes. After 15-minute rest in a sitting position, the electrocardiogram (ECG) recorded 512 heartbeats in a supine position. Thereafter, the same measure was taken in a standing position. During the test, the subjects quietly breathed in synchronosity with a 15/min (0.25 Hz) metronome signal to obtain stationary respiratory activity without frequency change or phase drift. R-wave detection by fast peak detection algorithm and spectrum computation by Fast Fourier transform enabled the study of the power spectrum of heart rate fluctuations. The power of fluctuations at different frequencies was the result of sympathetic and vagal input into the sinoatrial node. The autoregressive power spectral density of RR interval variability contained 2 major components: a high frequency (0.25 Hz), which is a quantitative marker of cardiac vagal activity, and a low frequency (<0.15 Hz), which is a quantitative marker of sympathetic activity with vagal modulation. A marked reduction in HF spectral density was found in diabetic patients relative to the normal controls (p<0.001). When neural activity was provoked through standing, less decreased HF spectral density and less increased LF spectral density were noted in diabetic patients relative to the normal controls (p<0.01). When diabetic autonomic neuropathy was advanced, HF and LF spectral density changes were lost. This method is simple, repeatible, objective, and quantitative. It may facilitate the screening of diabetic patients for autonomic neuropathy and enable convenient quantitative fallow-up.
Kwon, Sung-Ku,Kim, Du-Hyun The Korea Association of Crystal Growth 1999 한국결정성장학회지 Vol.9 No.5
In-situ cleaning and subsequent silicon epitaxial film growth were performed in a load-locked reactor equipped with Hg-grid UV lamp and PBN heater to obtain the smooth and contaminant-free underlying surface and develop low-temperature epitaxial film growth process. The removals of organic and native oxide were investigated using UV-excited $O_2$ and $NF_{3}/H_{2}$, and the effect of the surface condition was examined on the quality of silicon epitaxial film grown at temperature as low as $750^{\circ}C$. UV-excited gas phase cleaning was found to be effective in removing the organic and native oxide successfully providing a smooth surface with RMS roughness of 0.5$\AA$ at optimal condition. Crystalline quality of epitaxial film was determined by smoothness of cleaned surface and the presence of native oxide and impurity. Crystalline defects such as dislocation loops or voids due to the surface roughness were observed by XTEM.
Physiological Damages and Biochemical Alleviation to Ozone Toxicity in Five Species of genus Acer
Han, Sim-Hee,Kim, Du-Hyun,Lee, Kab-Yeon,Ku, Ja-Jung,Kim, Pan-Gi Korean Society of Forest Science 2007 한국산림과학회지 Vol.96 No.5
We investigated physiological damages and biochemical alleviation of five species of genus Acer under ozone fumigation in order to assess their tolerant ability against ozone toxicity. At the end of 150 ppb $O_3$ fumigation, photosynthetic characteristics were measured, and chlorophyll contents, malondialdehyde (MDA) and antioxidative enzyme activities were analyzed in the leaves of five maple trees (Acer buergerianum, A. ginnala, A. mono, A. palmatum, and A. palmatum var. sanguineum). The reduction of chlorophyll (chl) a in ozone-exposed plants was 16.8% (A. buergerianum) to 26.7% (A. ginnala) of control plants. For the content of chi b, A. ginnala and A. palmatum var. sanguineum represented the high reduction of 26.3% and 23.6%, respectively. The highest reduction on the chi a:b ratio was observed in the leaves of A. palmatum. The reduction of net photosynthesis in five species varied from 2.4% to 37.6%. Among five species, A. ginnala showed remarkable reduction (37.6%) for net photosynthesis in comparison with control. Carboxylation efficiency differed significantly (P < 0.05) among species and between control and ozone treatment. The reduction of carboxylation efficiency was the highest in the leaves of A. ginnala (44.7%). A. palmatum var. sanguineum showed the highest increase (41.7%) for MDA content. The highest increase of superoxide dismutase (SOD) activity represented in A. palmatum (26.1%) and the increase of ascorbate peroxidase (APX) activity ranged from 16.5% (A. ginnala) to 49.1% (A. palmatum var. sanguineum). A. mono showed the highest increase (376.6%) of glutathione reductase (GR) activity under ozone fumigation and A. buergerianum also represented high increase (42.3%) of GR activity. Catalse (CAT) activity increased in the leaves of A. ginnala, A. palmatun and A. palmatum var. sanguineum under ozone exposure, whereas A. buergerianum and A. mono decreased in comparison with control plants. In conclusion, physiological markers such as chlorophyll content and photosynthesis that responded sensitively to $O_3$ in maple trees were considered as the very important indicators in order to evaluate the tolerance against $O_3$ stress, and parameters were closely related with each other. Among anti oxidative enzymes, SOD and APX might be contributed to alleviate to $O_3$ toxicity through the increase of activity in all maple trees. Therefore, these compounds can be used as a biochemical maker to assess the stress tolerance to $O_3$.
Mechanical properties and durability of PMMA impregnated mortar
Priya Nair,이원묵,Du Hyun Ku,이철우,Jung Soon Park,Hun Young Park 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.1
Polymer impregnated concrete (PIC) is known to exhibit better strength and durability characteristics than the other classes of polymer cement composites. In the work described herein the monomer was impregnated into cement mortar and polymerized by two methods - the conventional thermal method and using microwaves. The mechanical properties and durability characteristics of the samples and on exposure to chemical environments were then evaluated. The above studies revealed that the strengths of PIC specimens were almost 2-3 times better than those of conventional cement mortars. The chemical resistance was also found to be superior even on prolonged exposure to the chemical media. This may be attributed to the protective layer formed by the polymer on the cement mortar, which prevents the external chemical media from interacting with the cement particles. The properties of the PIC specimens prepared by both methods have also been compared and discussed in this paper.
Han, Sim-Hee,Kim, Du-Hyun,Ku, Ja-Jung,Byun, Jae-Kyung,Lee, Jae-Cheon The Ecological Society of Korea 2010 Journal of Ecology and Environment Vol.33 No.4
The objective of our study was to investigate the major reasons for the different growth and visible injury on the needles of black pine growing in Ulsan and Yeocheon industrial complex areas, South Korea. After 12 years of growth, we collected climatic and air pollutant data, and analyzed soil properties and the physiological characteristics of black pine needles. Annual and minimum temperatures in Ulsan were higher than those in Yeocheon from 1996 to 2008. Ozone ($O_3$) was the pollutant in greatest concentration in Yeocheon, and whereas the $SO_2$ concentration in most areas decreased gradually during the whole period of growth, $SO_2$ concentration in Yeocheon has increased continuously since 1999, where it was the highest out of four areas since 2005. Total nitrogen and cation exchange capacity in Yeocheon soil were significantly lower than those of Ulsan. The average growth of black pine in Yeocheon was significantly smaller than that in Ulsan, and the growth of damaged trees represented a significant difference between the two sites. Photosynthetic pigment and malondialdehyde content and antioxidative enzyme activity in the current needles of black pine in Yeocheon were not significantly different between damaged and healthy trees, but in 1-year-old needles, there were significant differences between damaged and healthy trees. In conclusion, needle damage in Yeocheon black pine can be considered the result of long-term exposure to oxidative stress by such as $O_3$ or $SO_2$, rather than a difference in climatic condition or soil properties, and the additional expense of photosynthate needed to overcome damage or alleviate oxidative stress may cause growth retardation.