P型 α-多孔 SiC. 的光致發光光潽硏究

이기환,김영유,두영뢰,우배매 公州大學校 基礎科學硏究所 1998 自然科學硏究 Vol.7 No.-

The photoluminescence (PL) spectra from p-type a-porous silicon carbides prepared under UV photo-assisted process and under dark-current condition are investigated in detail. Emission bands with peak energies of 2.35, 2.50, 2.70, and 3.43 are resolved. The PL stability in tune and the PL difference arising from different tuning excitation energies are studied. It is found that the PL spectra of the a-porous silicon carbide depend strongly on the preparation conditions for electrochemical etching. The PL spectrum of the sample prepared under photo-assisted process has an enhancement on the lower-energy side of the emission; on the contray, another one under dark-current condition has an enhancement at the higher energy side, and the former stability is better than the latter one, and the latter PL intensity decreases with the increase of the time in the air. The reasons about these differences are discussed.

A Market Research on the Development Trends of Aerogel Daily Clothing

Du, Ying,Kim, Hee-Eun The Society of Fashion and Textile Industry 2019 한국의류산업학회지 Vol.21 No.1

The objective of this study is to analyze the development trends of aerogel daily clothing through market research, and to discuss the main points of future aerogel application in daily clothing. Market research on daily clothing has been conducted by collecting relevant information on the internet and analyzing the content of the information. We summarized the market research results in three aspects: the daily clothing brand using aerogel, the aerogel composite used in daily clothing, and the property of aerogel daily clothing. From these results, it can be seen that the development of aerogel daily clothing is becoming active and specialized. But there are still many difficulties due to lack of development experience. One problem is that the application methods of aerogel composite in current aerogel daily clothing are similar. Another problem is that the analysis of consumer reviews can only provides a rough understanding of the property of aerogel daily clothing. Therefore, further application research of aerogel composite in the field of daily clothing through scientific evaluation is required. It is expected to improve the performance of the aerogel daily clothing and increase the utilization of aerogel composite by conducting the further application research.

Temporal variation in the vertical distribution of microphytobenthos in intertidal flats of the Nakdong River estuary, Korea

Du, Guo Ying,Son, Moonho,An, Soonmo,Chung, Ik Kyo Elsevier 2010 Estuarine, coastal and shelf science Vol.86 No.1

<P><B>Abstract</B></P><P>The vertical distribution of microphytobenthos (MPB) was investigated in intertidal flats of the Nakdong River estuary over different temporal periods. The MPB biomass were measured as chlorophyll <I>a</I> concentration in the sediment, and monitored at two different depth scales. From August 2006 to August 2007, monthly sampling was carried out at four sites to a depth of 10cm. The vertical distribution exhibited an exponential decline with depth and the slope was closely related to sediment composition and MPB biomass in the surface sediment. The two slightly muddy sand (5–25% mud, <63μm) sites presented similar trends of seasonal variation to a sediment depth of 10cm, and no statistical difference was observed in their initial values and the slope of the exponential curves applied to each data set. The site with higher mud content also had higher surface biomass, and the fitted exponential curve had a larger slope than sites with more sand content. The seasonal variations of phaeo-pigments compared to chlorophyll <I>a</I> revealed higher grazing stress on the MPB in summer at the three slightly muddy sand sites, and low grazing stress all year around at the sand (<5% mud) site. In January, April and October 2007, and January 2008, diurnal sampling was conducted at hourly intervals at one slightly muddy sand site. The investigation in January 2007 which was conducted at 1cm intervals to a depth of 10cm sediment showed the migration mainly existed in the upper 1cm. The other diurnal sampling was undertaken to a 1cm depth at 0.5mm intervals. An evident migratory rhythm was present, with migration up to the surface during daytime emersion and down into deeper sediment during night and high tide submersion. Migrating cells could reach sediments as deep as 6 or even 10mm. When the visible thick biofilms formed, the migratory rhythm changed by keeping higher biomass at the surface even at night and during high tide submersion. Generally, the MPB surface biomass was an important factor in structuring the MPB vertical distribution. The vertical distribution to depths of 10cm was closely related to the sediment composition over the long term, while the MPB migration influenced the vertical distribution over the short term in the top 1cm of the sediment.</P>

Effect of light and sediment grain size on the vertical migration of benthic diatoms

Du, Guo Ying,Oak, Jung-Hyun,Li, Hongbo,Chung, Ik-Kyo The Korean Society of Phycology 2010 ALGAE Vol.25 No.3

Using chlorophyll fluorescence, the vertical migration of benthic diatoms responding to light intensity and affected by sediment grain size was studied. Minimal fluorescence ($F_o$) of surface sediment was measured by imaging pulse amplitude modulated (Imaging-PAM) fluorometer, and used to monitor diatom biomass variation in surface sediments. The test diatoms, Amphora coffeaeformis (C. Agardh) K$\ddot{u}$tzing and Cylindrotheca closterium (Ehrenberg) Reimann & Lewin, migrated to the sediment surface under irradiance from 50 to 500 ${\mu}mol$ photons $m^{-2}s^{-1}$. However, the diatoms exhibited no evident increase of surface biomass under dark conditions, and even showed slightly decrease of surface biomass under irradiances over 1,000 ${\mu}mol$ photons $m^{-2}s^{-1}$. The light intensity inducing the maximum surface migration of A. coffeaeformis was 100 ${\mu}mol$ photons $m^{-2}s^{-1}$, while the light intensity producing the same effect for C. closterium was 250 ${\mu}mol$ photons $m^{-2}s^{-1}$. C. closterium showed higher motility than A. coffeaeformis. Faster diatom surfacing was observed in larger grain size sediments (125-335 ${\mu}m$) than smaller ones (63-125 ${\mu}m$). This study confirmed the significant influence of light as a main triggering factor behind migration, indicated the distinct effect of different sediment grain size, and highlighted the species-specific migratory ability.

A Market Research on the Development Trends of Aerogel Daily Clothing

( Ying Du ),( Hee-eun Kim ) 한국의류산업학회 2019 한국의류산업학회지 Vol.21 No.1

The objective of this study is to analyze the development trends of aerogel daily clothing through market research, and to discuss the main points of future aerogel application in daily clothing. Market research on daily clothing has been conducted by collecting relevant information on the internet and analyzing the content of the information. We summarized the market research results in three aspects: the daily clothing brand using aerogel, the aerogel composite used in daily clothing, and the property of aerogel daily clothing. From these results, it can be seen that the development of aerogel daily clothing is becoming active and specialized. But there are still many difficulties due to lack of development experience. One problem is that the application methods of aerogel composite in current aerogel daily clothing are similar. Another problem is that the analysis of consumer reviews can only provides a rough understanding of the property of aerogel daily clothing. Therefore, further application research of aerogel composite in the field of daily clothing through scientific evaluation is required. It is expected to improve the performance of the aerogel daily clothing and increase the utilization of aerogel composite by conducting the further application research.

Identification and Characterization of Gonatobotryum apiculatum Causing Leaf Spot and Blight on Sinowilsonia henryi

( Ying Gao ),( Hai Feng Liu ),( Zheng Xing Song ),( Xiao Ying Du ),( Jian Xin Deng ) 한국균학회 2020 Mycobiology Vol.48 No.1

Sinowilsonia henryi is a rare and endangered plant, as well as an endemic species in China. In July 2018, leaf spot and blight disease was observed on S. henryi in Yichang, Hubei, China. A fungus isolated from disease tissues was identified as Gonatobotryum apiculatum based on morphology and sequence analyses of ITS and LSU regions. Phylogenetic analyses indicated that the species belongs to Dothioraceae (Dothideales). Morphologically, the species produced two distinct types of conidia from authentic media, both conidia were described here. Pathogenicity tests showed that the fungus is a pathogen causing leaf spots on S. henryi. This is the first report of leaf spot and blight disease on S. henryi caused by G. apiculatum in China.

Estimating Areal Production of Intertidal Microphytobenthos based on Spatio-Temporal Community Dynamics and Laboratory Measurements

Guo Ying Du,정익교 한국해양과학기술원 2009 Ocean science journal Vol.44 No.4

In situ Microphytobenthic community dynamics were combined with laboratory measurement of predominant species by fluorescence methods to estimate the areal primary production. Field investigation of community dynamics of microphytobenthos (MPB) was conducted from August 2006 to August 2007 in intertidal flats of the Nakdong River estuary, Korea. MPB Biomass varied between 0.47 and 16.58 μg cm−3 in the surface 1 cm sediment, with two dominant diatom species, Amphora coffeaeformis and Navicula sp., occupying average 77.2 ± 14.9% of total number of MPB cells. The biomass was higher in the slightly muddy sand sites than that in the sand site, and showed different pattern of seasonal variation. The profile of vertical distribution of biomass was an exponential decrease trend with depth in sediments. The biomass proportions in the uppermost 3 mm were 57.6% and 37.8% with and without the presence of biofilm, respectively. The two dominant species were cultured in laboratory, and their photosynthetic parameters, rETRmax (relative maximum electron transport rate), α (light utilization coefficient) and Ek (light saturation parameter) were derived from rETR (relative ETR)-irradiance curves by Imaging- PAM (pulse amplitude modulated) fluorometry. The rETR-irradiance curves showed no significant difference of photosynthetic activities between the two species. The areal potential production ranged from 0.74 to 2.22 g C m−2 d−1. In situ Microphytobenthic community dynamics were combined with laboratory measurement of predominant species by fluorescence methods to estimate the areal primary production. Field investigation of community dynamics of microphytobenthos (MPB) was conducted from August 2006 to August 2007 in intertidal flats of the Nakdong River estuary, Korea. MPB Biomass varied between 0.47 and 16.58 μg cm−3 in the surface 1 cm sediment, with two dominant diatom species, Amphora coffeaeformis and Navicula sp., occupying average 77.2 ± 14.9% of total number of MPB cells. The biomass was higher in the slightly muddy sand sites than that in the sand site, and showed different pattern of seasonal variation. The profile of vertical distribution of biomass was an exponential decrease trend with depth in sediments. The biomass proportions in the uppermost 3 mm were 57.6% and 37.8% with and without the presence of biofilm, respectively. The two dominant species were cultured in laboratory, and their photosynthetic parameters, rETRmax (relative maximum electron transport rate), α (light utilization coefficient) and Ek (light saturation parameter) were derived from rETR (relative ETR)-irradiance curves by Imaging- PAM (pulse amplitude modulated) fluorometry. The rETR-irradiance curves showed no significant difference of photosynthetic activities between the two species. The areal potential production ranged from 0.74 to 2.22 g C m−2 d−1.

Effect of light and sediment grain size on the vertical migration of benthic diatoms

Guo Ying Du,옥정현,Hongbo Li,정익교 한국조류학회I 2010 ALGAE Vol.25 No.3

Using chlorophyll fluorescence, the vertical migration of benthic diatoms responding to light intensity and affected by sediment grain size was studied. Minimal fluorescence (Fo) of surface sediment was measured by imaging pulse amplitude modulated (Imaging-PAM) fluorometer, and used to monitor diatom biomass variation in surface sediments. The test diatoms, Amphora coffeaeformis (C. Agardh) Kützing and Cylindrotheca closterium (Ehrenberg) Reimann & Lewin,migrated to the sediment surface under irradiance from 50 to 500 μmol photons m-2 s-1. However, the diatoms exhibited no evident increase of surface biomass under dark conditions, and even showed slightly decrease of surface biomass under irradiances over 1,000 μmol photons m-2 s-1. The light intensity inducing the maximum surface migration of A. coffeaeformis was 100 μmol photons m-2 s-1, while the light intensity producing the same effect for C. closterium was 250μmol photons m-2 s-1. C. closterium showed higher motility than A. coffeaeformis. Faster diatom surfacing was observed in larger grain size sediments (125-335 μm) than smaller ones (63-125 μm). This study confirmed the significant influence of light as a main triggering factor behind migration, indicated the distinct effect of different sediment grain size,and highlighted the species-specific migratory ability.

Migratory Responses of Benthic Diatoms to Light and Temperature Monitored by Chlorophyll Fluorescence

Guo Ying Du,Wen Tao Li,Hongbo Li,정익교 한국식물학회 2012 Journal of Plant Biology Vol.55 No.2

As an important adaptation for survival in the sediments of intertidal flats, benthic diatoms move up and down in response to a wide range of environmental stimuli. We investigated the vertical migration of two diatoms—Cylindrotheca closterium (Agradh) Kützing (B-25) and Nitzschia sp. (B-3)—under different combinations of light intensity and temperature conditions. An imaging pulse amplitude modulated (PAM) fluorometer was used to measure the minimum fluorescence (F0) in order to monitor variations in diatom biomass in surface sediments. Rapid light curves (RLCs) were applied to assess their photosynthetic activities. Both species had increased motility under higher temperatures, with the longer valved C. closterium being twice as fast as the shorter valved Nitzschia sp. The former was also influenced by exposure to light intensities of 100 or 250 μmol m−2 s−1, whereas the latter was not. Consequently, no light/temperature interaction effect was associated with the vertical migration of Nitzschia sp., perhaps because of its lower photosynthetic capacity and smaller cell size. Therefore, we conclude that motile benthic diatoms exhibit species-specific responses to light and temperature due to differences in their photosynthetic capability and morphological characteristics.

Constituents from Zhuyeqing Liquor with hepatoprotective effect on alcohol-induced HepaG 2 toxicity

Hong-Ying Gao,Guo-Yu Li,Hang-Yu Wang,Jian Huang,Xiao-Wei Du,Ying Han,Li-Fei Wang,Jin-Hui Wang 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.5

An unprecedented new skeleton compound (1R,10R, 11S)-10,11-dimethyl-4-formyl-2,9-dioxa-bicyclo [5.4.0]undeca-4,6-dien-3-one (1), monoterpenoids and monoterpeneglycoside picrocrocinic ester (2), epijasminoside B (3) and 60 -O-(3-methoxyl-4-hydroxyl-coumaroyl)-epijasminoside B (4),along with 26 known compounds, were obtained fromZhuyeqing Liquor. These compounds were identified mainlyby analyzing their NMR, HR-ESI–MS and CD data. The isolatedcompounds were screened against alcohol induced HepaG2 toxicity for hepatoprotective assay. Compounds 10, 19,21 and 26 displayed the highest potency against alcoholinduced HepaG 2 toxicity with the cell viability ratio 41.21,56.91, 67.69 and 70.32 % respectively.