• Food Science of Animal Resources
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• v.26 no.2
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• pp.166-174
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• 2006

To determine the proper processing and storage conditions, physico-chemical, microbial and sensory properties of venison jerky under different dry times were measured during storage at $30^{\circ}C$ for 28 days. Samples were dried for 3 hr (T1), 4 hr (T2) and 5 hr (T3) at $75^{\circ}C$ in the smoke chamber, respectively. The pH of T1 was slightly lower than those of T2 and T3 as storage time increased. As dry and storage time increased, TBARS of T2 and T3 were significantly higher (p<0.05) than that of T1. In meat color, $L^*$ values of T3 showed slightly higher than those of T1 and T2, while at values were not clearly tendency by the passage of storage time. $b^*$ values of T2 and T3 were higher than that of T1. The water activity were significantly lower (p<0.05) in ,the order of T3$log_{10}$ CFU/g until 28 days and its number were accepted by sensory evaluation. In conclusions, T2 and T3 showed slightly high overall acceptability and lipid oxidative stability compared to T1 conditions. These results indicated that longer dry time ($4{\sim}5 hr$) of venison jerky would be better characteristics as compared to shorter dry time (3 hr) with increased storage time at $30^{\circ}C$.

• Journal of Biomedical Engineering Research
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• v.25 no.5
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• pp.421-430
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• 2004

Clinically, it is almost impossible for a physician to distinguish subtle changes of frequency spectrum by using a stethoscope alone especially in the early stage of thrombus formation. Considering that reliability of mechanical valve is paramount because the failure might end up with patient death, early detection of valve thrombus using noninvasive technique is important. Thus the study was designed to provide a tool for early noninvasive detection of valve thrombus by observing shift of frequency spectrum of acoustic signals with computer aid diagnosis system. A thrombus model was constructed on commercialized mechanical valves using polyurethane or silicon. Polyurethane coating was made on the valve surface, and silicon coating on the sewing ring of the valve. To simulate pannus formation, which is fibrous tissue overgrowth obstructing the valve orifice, the degree of silicone coating on the sewing ring varied from 20％, 40％, 60％ of orifice obstruction. In experiment system, acoustic signals from the valve were measured using microphone and amplifier. The microphone was attached to a coupler to remove environmental noise. Acoustic signals were sampled by an AID converter, frequency spectrum was obtained by the algorithm of spectral analysis. To quantitatively distinguish the frequency peak of the normal valve from that of the thrombosed valves, analysis using a neural network was employed. A return map was applied to evaluate continuous monitoring of valve motion cycle. The in-vivo data also obtained from animals with mechanical valves in circulatory devices as well as patients with mechanical valve replacement for 1 year or longer before. Each spectrum wave showed a primary and secondary peak. The secondary peak showed changes according to the thrombus model. In the mock as well as the animal study, both spectral analysis and 3-layer neural network could differentiate the normal valves from thrombosed valves. In the human study, one of 10 patients showed shift of frequency spectrum, however the presence of valve thrombus was yet to be determined. Conclusively, acoustic signal measurement can be of suggestive as a noninvasive diagnostic tool in early detection of mechanical valve thrombosis.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.2
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• pp.70-80
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• 2003

We report the first direct measurement of $CO_2$ flux over Kwangneung broadleaf deciduous forest, one of the tower flux sites in KoFlux network. Eddy covariance system was installed on a 30 m tower along with other meteorological instruments from June to August in 2002. Although the study site was non-ideal (with valley-like terrain), turbulence characteristics from limited wind directions (i.e., 90$\pm$45$^{\circ}$) was not significantly different from those obtained at simple, homogeneous terrains with an ideal fetch. Despite very low rate of data retrieval, preliminary results from our analysis are encouraging and worthy of further investigation. Ignoring the role of advection terms, the averaged net ecosystem exchange (NEE) of $CO_2$ ranged from -1.2 to 0.7 mg m$^{-2}$ s$^{-1}$ from June to August in 2002. The effect of weak turbulence on nocturnal NEE was examined in terms of friction velocity (u*) along with the estimation of storage term. The effect of low uf u* NEE was obvious with a threshold value of about 0.2 m s$^{-1}$ . The contribution of storage term to nocturnal NEE was insignificant; suggesting that the $CO_2$ stored within the forest canopy at night was probably removed by the drainage flow along the hilly terrain. This could be also an artifact of uncertainty in calculations of storage term based on a single-level concentration. The hyperbolic light response curves explained ＞80% of variation in the observed NEE, indicating that $CO_2$ exchange at the site was notably light-dependent. Such a relationship can be used effectively in filling up the missing gaps in NEE data through the season. Finally, a simple scaling analysis based on a linear flow model suggested that advection might play a significant role in NEE evaluation at this site.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.145-156
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• 2006

The objective of this study was to evaluate biological health conditions and physicochemical status using multi-metric models at five sites of the Keum-Ho River during August 2004 and June 2005. The research approach was based on a qualitative habitat evaluation index (QHEI), index of biological integrity (IBI) using fish assemblage, and long-term chemical data (1995 ${\sim}$ 2004), which was obtained from the Ministry of Environment, Korea. For the biological health assessments, regional model of the IBI in Korea (An,2003), was applied for this study. Mean IBI in the river was 30 and varied from 23 to 48 depending on the sampling sites. The river health was judged to be "fair condition", according to the stream health criteria of US EPA (1993) and Barbour et al. (1999). According to the analysis of the chemical water quality data of the river, BOD, COD, conductivity, TP, TN, and TSS largely varied epending on the sampling sites, seasons and years. Variabilities of some parameters including BOD, COD, TP, TN, and conductivity were greater in the downstream than in the upstream reach. This phenomenon was evident in the dilution by the rain during the monsoon. This indicates that precipitation is a very important factor of the chemical variations of water quality. Community analyses showed that species diversity index was highest (H=0.78) in the site 1, while community dominance index was highest in the site 3, where Opsariichthys uncirostris largely dominated. In contrast, the proportions of omnivore and tolerant species were greater in the downstream reach, than in the upstream reach. Overall, this study suggests that some sites in the downstream reach may need to restore the aquatic ecosystem for better biological health.

• Journal of Life Science
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• v.16 no.6
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• pp.984-988
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• 2006

Lipopolysaccharide(LPS) was posttreated after the 14 day-pretreatment of Ulva lactuca fractions(ULF), and their correlativity to enzymatic activity alteration was investigated in the liver of rats. ULF was intraperitoneally administered into rats at dose of $1m{\ell}/kg$ of 100 mg/kg concentration for 14 days. On the day 15, $1m{\ell}/kg$ of LPS was injected. The corelativity was examined by measuring the changed values of superoxide dismutase(SOD) in mitochondrial fraction and catalase(CAT), glutathione peroxidase(GPx) in liver homogenate. The results showed that LPS treatment decreased the high values of SOD, CAT, GPx to the low values, but ULF pretreatment increased the low values of SOD, CAT, GPx to the high values. It was suggested that ULF, LPS and antioxidative enzymes like SOD, CAT, GPx had the corelativity of the high-low-high pattern and that the ULF pretreatment played the proper preventive role in the protection against the LPS treatment-induced enzymatic inactivity in the water fraction.

• Korean Journal of Health Education and Promotion
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• v.1 no.1
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• pp.83-97
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• 1983

The present study is to provide information for the improvement of school health services through research on the current condition of its organization and practice in universities, colleges and junior colleges. The scope of this study is consisted of four components including health organizations/units, school health services, environmental sanitation and health education for the 30 universities, the 20 colleges and the 32 junior colleges in Korea. The major findings are summarized as follows: (1) Among the sampled schools, around 73% of them have the health service organization/unit. When we break down health service organization/unit into the types by the level of school, around 73% of the universities have formal organization called "health center" and 20.0% of them have an informal organization called "health room". For the colleges level, 30.0% of them have the "health center" and 40.0% of them have the "health room". The figure of junior colleges is a quite different from universities and colleges, 56.3% of junior colleges have the "health room" only but the other have no service organization at all. (2) It was found that only 22.0% of 82 schools have the health committee for the school health services. It might be necessary to have a kind of expert committee to establish an annual health service program, budget and health policy in the school. (3) Approximately 29% of those schools having formal health organizations/units appointed directors as a medical persons. 13.4% of the sampled schools are appointed doctors (including the dentists) at health service organization/unit, 9.8% are appointed pharmacist and 65.9% are appointed nurses. Therefore, the data imply that the school health services are depending mainly on nurses. (4) The major activities of school health services are covering primary medical care (84.1%), health counseling (72.0%), physical examination (68.3%), vaccination (58.5%), tuberculosis control (54.9%), parasite control (29.3%) and dental health case(9.8%). Also 69.5% of the schools have the program on the environmental sanitation and the health education program. (5) In regard to health budget taking account of 34 schools, approximately 92% of them have less than 5,000 won per students and only 8.8% of them have more 10,000 won per students. At the average health budget per students is 4089.8 won in universities, 1617.1 won in colleges and 475.0 won in junior colleges. (6) The students enjoy the benifit of medical insurance at 11.0% of 82 schools surveyed. They are all universities. (7) The study found that 56 universities, colleges and junior colleges provide the annual physical examination. Only 21.4% of them have provided it for all students and school employees. (8) 64.3% of the 56 schools surveyed keep a record of the regular physical examinations. Records must be utilized as the basic data for the evaluation of the student's health condition and so the individual student is encouraged to take care of his own health. (9) At the 59 schools which practice health counseling, the main concerns of the counsellees are venereal disease, tuberculosis and psychoneurosis. This shows the need to practice health education in the area of preventive medicine. (10) 69.5% of the 82 universities, colleges and junior colleges surveyed are concerned with supervision of the environmental sanitation in their school, but non-professionals are in charge at 70.1% of them. This indicates negligence in environmental sanitation. (11) 53.7% of the 82 schools responded that they have no special instructive measure for the students' health and 54.9% are found to be negative in the use of a health education method. This reveals a problem. They are not positive to the recognition of their function as the initiative organization for the students' health. (12) The supplementary education for the faculty of the school health services is executed only at 8.5% of all the schools surveyed.

• Journal of The Korean Association For Science Education
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• v.24 no.5
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• pp.851-868
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• 2004

The main purposes of this study is to develop a web-based STS biology instruction program (WB-STS) for the scientifically gifted students. The specific main research questions were as follows; 1. How can the WB-STS for biology education be developed and what are the primary components involved in it? 2. Is there any proper validity for developed the WB-STS in biology education? To solve the above mentioned problems, several procedures were applied. First, in order to develop WB-STS for the scientifically gifted students, NCISE, Renzulli' s Enrichment Triad Model and the Iowa Chautauqua program's main characteristics were analyzed systematically and the principles and general process for constructing WB-STS were examined. Additionally, the needs of students and the goals of Biology education were identified thoroughly. And then all these ideas were embodied in an agenda for constructing WB-STS. Second, to analyse the validity and utility of developing WB-STS, a questionnaire was developed and submitted to seven specialists and a group of twenty students who would participate in the experiment later. The main results of study are summarized below: First, WB-STS appeared to be successfully constructed based on Renzulli' s Enrichment Triad Model and the Iowa Chautauqua program. Its main features are that it was made emphasizing a learner-centered approach and constructive learning. It is composed of five steps: Scientific theme selection -${\rightarrow}$Exploration ${\rightarrow}$ Concept & Principle Check ${\rightarrow}$ Finding Solution ${\rightarrow}$ Action. Second, seven specialists and a group of students assessed the developed WB-STS's validity and utility with a questionnaire, the results appeared satisfactory. Students showed high interest in WB-STS and gave a positive evaluation of WB-STS.

• Journal of The Korean Association For Science Education
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• v.33 no.7
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• pp.1431-1449
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• 2013

This study is based on the assertion that science museums should consider visitors' views and expectations as they are not satisfied in many cases. In this study, we investigated 31 scientifically gifted students and 177 science high school students about their image of science museums. Using the questionnaire, it was found that only 51% of students visited science museums; however, the average number of visits was 4.2. This means that students tended to re-visit after the first visit of the science museum. Students had a 'good' image of science museums when they incurred hands-on experiences and observed new, interesting, curious and funny exhibits. And students had a 'bad' image of science museums due to the following aspects: lack of new and interesting exhibits, information and guide, diverse contents, and hands-on experience; deficiencies in environment; and inadequacy of the management, operation and composition of exhibits. Therefore, they hoped that science museums will provide more hands-on experiences and experiments, new and interesting exhibits, systematic management and composition of exhibits, information and guides, and a good environment. So science museums need to pay special attention to aspects like management, information guides and environment for the first-time visitors. Based on the above results, we suggested "Directions for a good science museum based on students' views". While asking students what topics they wanted to know and learn in a science museum, each student was given the choice of four topics; eventually, 2.9 answers overlapped for each topic. When classifying students' topics into four main themes for the Gwangju National Science Museum, the order from the most popular theme to the least one was 'science in everyday life', 'ocean/space/future science', 'light and science', and 'culture, art and science'. Among the topics mentioned by students, only 37% are exhibited in Seoul, Gwacheon, Daejeon, or Gwangju science museums. We hope that the results and research methods will be used for evaluation, re-construction, and reinvigorated presentation of science museums.

• Korean Chemical Engineering Research
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• v.58 no.1
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• pp.84-91
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• 2020

The efficiency of the synthetic magnesium silicate used in basic polyols and edible oil purification is evaluated by its purification ability and filtration rate and is affected by the particle size and surface area of magnesium silicate. In this study, it was investigated the change on the particle size of magnesium silicate was influenced by the reaction temperature, injection rate, injection order (Si, Mg) and Mg/Si reaction mole ratio. The synthesized magnesium silicate was compared and analyzed for the synthesis, grinding, and refining processes. In the synthesis process, the reaction temperature and feed rate did not affect the average particle size change of magnesium silicate, while the reaction molar ratio of Mg / Si and the order of injection acted as main factors for the change of average particle size. The average particle size of magnesium silicate increased by 8.7 ㎛ from 54.4 ㎛ to 63.1 ㎛ at Mg injection when Mg molar ratio increased from 0.125 to 0.500, and increased by about 4.8 ㎛ from 47.3 ㎛ to 52.1 ㎛ at Si injection. The average particle size according to the order of injection was 59.1 ㎛ for Mg injection and 48.4 ㎛ for Si injection and the difference was shown 10.7 ㎛, therefore the filtration rate was about 2 times faster under the condition of Mg injection. That is, as the particle size increases, the filtration time is shortened and washing filtration rate can be increased to improve the productivity of magnesium silicate. The cake form of separated magnesium silicate after filtration becomes a solid through drying process and is used as powdery adsorbent through the grinding process. As the physical strength of the dried magnesium silicate increased, the average particle size of the powder increased and it was confirmed that this strength was affected by the reaction molar ratio. As the reaction molar ratio of Mg / Si increased, the physical strength of magnesium silicate decreased and the average particle size after grinding decreased by about 40% compared to the average particle size after synthesis. This reduction of strength resulted in an improvement of the refining ability due to the decrease of the average particle size and the increase of the amount of fine particle after the pulverization, but it resulted in the decrease of the purification filtration rate. While the molar ratio of Mg/Si was increased from 0.125 to 0.5 at Mg injection, the refining ability increased about 1.3 times, but the purification filtration rate decreased about 1.5 times. Therefore, in order to improve the productivity of magnesium silicate, the reaction molar ratio of Mg / Si should be increased, but in order to increase the purification filtration rate of the polyol, the reaction molar ratio should be decreased. In the synthesis parameters of magnesium silicate, the order of injection and the reaction molar ratio of Mg / Si are important factors affecting the changes in average particle size after synthesis and the changes of particle size after grinding due to the changes of compressive strength, therefore the synthetic parameter is an important thing that determines productivity and refining capacity.

• Asian Journal of Turfgrass Science
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• v.22 no.2
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• pp.149-160
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• 2008

This study was carried out to examine the growth performance of 10 cultivars of creeping bentgrass under salt injury in Seo-san reclaimed area. Turfgrass performance studies included 10 creeping bentgrass cultivars (T-1, L-93, Penn A1, Pennlinks II, Seaside II, Declaration, Penn A4, Crenshaw, Dominant, and Penncross). Ten creeping bentgrass cultivars were grown on a USGA recommended research green. Plots were seeded on May 31, 2006 at the rate of $7\;g{\cdot}m^{-1}$. Electric conductivities of irrigation water (ECw) and soil (ECe) were ranged from 0.28 to $3.3\;d\;S{\cdot}m^{-1}$ and from 0.25 to $3.5\;d\;S{\cdot}m^{-1}$ respectively. Leaf color, turf quality, coverage rate, and growth rate were checked under the salty condition in reclaimed land for 2 year. Creeping bentgrass cultivars of T-1, Penn links, and Crenshaw presented dark green color and Penn A1, Declaration showed lighter green color. Penn A1, Penn A4 and L-93 exhibited the highest overall turfgrass quality. Average visual coverage was 75.3% after eleven weeks after seeding. Dominant, L-93, and Penn A1 resulted in higher visual coverage compared to the other cultivars. There was no difference in density among cultivars at 1 year after establishment. However, Declaration, Penn A1, T-1, and L-93 showed higher density compared to the other cultivars at 2 years after seeding. Creeping bentgrass showed different quality, density and color in salty soil (ECe: $0.25-3.5\;d\;S{\cdot}m^{-1}$) and from application of salty irrigation water (ECw: $0.28-3.3\;d\;S{\cdot}m^{-1}$) conditions. These results will be useful where selecting green cultivars for the golf courses in reclaimed land area.