• Microbiology and Biotechnology Letters
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• v.50 no.4
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• pp.548-556
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• 2022

Acylases can have a significant effect on biofilm formation owing to their quorum quenching activity. In this study, we investigated the effects of acylase treatment episodes on multispecies biofilm development. A consortium composed of 9 species belonging to different genera was allowed to form biofilms for 5 days under various treatment episodes (different treatment periods, 1, 2, 3, or 4 days; and two application timings, beginning or later) at 1, 5, 10, 20 and 50 mg·l^-1 acylase concentrations. The acylase treatment for 5 days showed that acylase concentration was negative with biofilm development (linear regression, Y = -0.05·x + 2.37, p < 0.05, R² = 0.88). Acylase was more effective in reducing biofilm formation when it was applied in the beginning (vs. in later development stage) at all acylase concentrations (p < 0.05). ANOVA indicated that treatment period was significant on biofilm formation in both application timings at ≥ 10 mg·l^-1 (p < 0.05). Linearity test results showed that all slope values between period and biofilm were negative in both timings at ≥ 10 mg·l^-1 (p < 0.05, except for the later application at 20 mg·l^-1). When temporal biofilm dynamics were monitored at 20 mg·l^-1, biofilms gradually increased with time at all treatment episodes (p < 0.05), and slope values in linear regression between biofilm and time were lower when acylase was applied in the beginning (p < 0.05). Our findings suggest the importance of the acylase treatment period and application timing on biofilm control.

• The Korean Journal of Malacology
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• v.30 no.2
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• pp.107-116
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• 2014

Gonadal development and maturation mechanism were studied on the freshwater marsh clam Corbicula papyracea (Heude), which is the endangered species in Korea. The specimens were collected in the rearing ponds and waterway of NFRDI in Gapyeong-gun, Gyeonggi-do from January to December 2004, and then investigated by condition factor, relative growth, gonadal development phases and gonad histological characters based on 30-50 individuals every month. Comparing with the freshwater marsh clam, C. papyracea is small, light olive brown shell and violet interior. The hermaphrodite individuals of C. papyracea take an internal fertilization and fertilized eggs are stored in the foster-sack in the gills, then the hatched juveniles are released outside after an ovoviviparous process. The average water temperature of inhabit area was in range of $1.8-27.0^{\circ}C$ and usually took great effects on the gonad maturation of C. papyracea. The condition factor ranged from 0.14 to 0.21 throughout the year, which was the lowest during winter season (December-February), and gradually increased to the highest value of 0.21 in May. The ratio of meat weight to total weight was 25.9-38.7%, indicating the similar trend with condition factor. The highest values of condition factor and the ratio of meat weight appeared 1-2 months later than gonadosomatic index reached the peak value, it was probably because that the ovoviviparous eggs would spend a long period before hatching from the foster-sack in the gills. To synthesize the characters of meat weight, condition factor and gonad development by histological study, reproductive cycle of C. papyracea could be divided into five successive stages: multiplicative stage (December to February), growing stage (February to May), mature stage (June to August), spawning stage (August to November), recovery stage (November to December). The smallest shell length of matured C. papyracea was 12.6 mm, and individuals, larger than 16 mm, was formed the nursery in the gills.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.2
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• pp.166-181
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• 2003

With the rapid growth of Internet, many devices such as Web TVs, PDAs and Web phones, begin to be directly connected to the Internet. These devices need real-time operating systems (RTOS) to support complex real-time applications running on them. Development of such real-time applications called embedded internet applications, is difficult due to the lack of adequate tools, especially debuggers. In this paper we present a new tracepoint debugging tool for the Qplus-T RTOS embedded system, which facilitates the instrumentations of the real-time software applications with timing trace-points. Compared with traditional breakpoint debugger, this trace-point debugger provides the ability to dynamically collect and record application data for on-line examination and for further off-line analysis. And, the trace-points can also provide the means for assigning new values to the running application's variables, without neither halting its execution nor interfering with its natural execution flow. Our trace-point debugger provides a highly efficient method for adding numerous monitoring trace-points within a real time target application such as Qplus-T internet applications, utilizing these trace-points to monitor and to analyze the application's behavior while it is running. And also, our trace debugger is different from previous one in that we can specify and detect the timing violations using its RTL (Real-Time Logic) trace experiments.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.2
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• pp.139-145
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• 2015

Rice ratooning is the production of a second rice crop from the stubble left behind after the main-crop harvest. The main advantage of rice ratooning is that in areas where rice is the main crop, double crop of rice can be grown for additional returns. Eight cultivars of rice were tested for estimation their ratooning ability. The main crop was harvested at mass maturity, after which the tillers were mowed to stubbles of about 10 cm tall. And then left without any further input, until the ratooned plant were ready for harvest. Highly significant variations were detected in the ratoon performance among cultivars, with ratoon ability ranging from 0% ('Unkwang', 'Jopeyong', 'Odae', 'Nokyang') to 33% ('Jinbuol') in their grain yield. The maximum grain yield from ratoon rice was 202 and 203 kg/10a for 'Jinbuol' and 'Joun' followed by 'Junamjoseng' 174kg/10a. Protein and amylose contents of ratoon rice were more increased than those of main rice. The platability value of cooked rice of ratoon was lower than that of main crop. Germination rate of the previous year's harvest of rice was not significantly different between ratoon and main crop. This rice ratooning system requires short duration, creating possibility for growing another crop in the same cropping year and offers an opportunity to increase cropping intensity per unit of cultivated areas.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.2
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• pp.167-173
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• 2015

Green manure crops are organic materials that can supply organic matter and substitute chemical fertilizer, yet emit methane while being decomposed. Therefore, we experimented with different kinds of Green manure crops and tillage depth in order to decrease the amount of methane emitted when utilizing Green manure crops in paddy soil. The amount of methane emitted during the cultivation period of rice started to increase after transplanting and peaked at 63, and 74 days after transplanting, than decreased to almost none starting from 106 days. According to the kind of Green manure crop, it was highest in barley, then hairy vetch and chemical fertilizer. Depending on the tillage depth, the amount of methane emitted decreased by 22.5% in chemical fertilizer, 12.4% in hairy vetch and 11.7% in barley in 20cm tillage compared to 10cm tillage. The air temperature of methane test period was $30{\sim}40^{\circ}C$, and the soil temperature was more than about $2{\sim}10^{\circ}C$ lower than the air temperature. Due to the irrigation started before transplanting, the oxidation-reduction potential (Eh) of soil was rapidly reduced, and showed negative (-) values. Eh values mostly kept the range of -300~-500 mV during rice cultivation. It rapidly increased 106 days after transplanting. Rice yield the highest in hairy vetch and did not show differences according to tillage depth. Methane emission could be effectively reduced if the paddy soil was tilled by 20 cm during the application of hairy vetch.

• Journal of Korea Water Resources Association
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• v.45 no.3
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• pp.275-290
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• 2012

In this study, we have developed an optimal time distribution model through extraction of peaks over threshold (POT) series. The median values for annual maximum rainfall dataset, which are obtained from the magnetic recording (MMR) and the automatic weather system(AWS) data at Seoul meteorological observatory, were used as the POT criteria. We also suggested the improved methodology for the time distribution of extreme rainfall compared to Huff method, which is widely used for time distributions of design rainfall. The Huff method did not consider changing in the shape of time distribution for each rainfall durations and rainfall criteria as total amount of rainfall for each rainfall events. This study have suggested an extracting methodology for rainfall events in each quartile based on interquartile range (IQR) matrix and selection for the mode quartile storm to determine the ranking cosidering weighting factors on minutely observation data. Finally, the optimal time distribution model in each rainfall duration was derived considering both data size and characteristics of distribution using kernel density function in extracted dimensionless unit rainfall hyetograph.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.328-334
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• 2013

A greenhouse heating system to improve heat pump performance using inside and outside air of greenhouse as a heat source selectively and cut $CO_2$ enrichment costs by delay of greenhouse ventilation was developed. In this system, thermal storage modes divided into inside circulation mode using surplus solar energy and outside circulation mode using outside air heat. The thermal storage modes were designed to be switched mutually according to inside greenhouse temperature and six temperature values were input to control the heat pump operating, thermal storage mode switching and greenhouse heating automatically. Operating characteristics of this system were tested in a plastic greenhouse of non-ventilation condition. The results of test showed that the inside circulation mode began at about 11:00 and lasted for about 210 minutes and inside greenhouse temperature was maintained between $20{\sim}28^{\circ}C$ in spite of non-ventilation. System heating COP of the inside circulation mode in the daytime was 3.35, which was 36% and 25% higher than that of the outside circulation modes in the nighttime and daytime respectively.

• Analytical Science and Technology
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• v.26 no.6
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• pp.401-406
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• 2013

Oxygen($O_2$) consumption and carbon dioxide($CO_2$) excretion of a fertile chicken egg during incubation were measured by a gas mass spectrometer. A closed sample chamber was developed to collect gas samples during the 20 days of artificial incubation of both a fertile and an infertile egg. After leaving an egg in the sample chamber for an hour, using a gas-tight syringe, samples of 2 mL of gas were collected from the closed sample chamber and analyzed using a gas mass spectrometer in 2~4 day intervals. The $O_2$ consumption and $CO_2$ excretion of chicken embryos increased rapidly after 10 days from the starting point of incubation. After 20 days, 23 mL of $O_2$ was consumed and 16 mL of $CO_2$ was excreted per hour. Throughout the whole period of incubation, concentration of $O_2$ decreased 4.3 mol% and $CO_2$ increased only 3.1 mole%, i.e., the mole of consumed $O_2$ and the mole of excreted $CO_2$ were not the same. On the other hand, during the same period, concentration of $N_2$ increased about 1.3 mol% and the increased mole fraction of $N_2$ was comparable with the difference (1.2 mol%) between the mole fraction of consumed $O_2$ and excreted $CO_2$. Therefore, we can attribute the increase of $N_2$ mole% to the difference of mole fraction between consumed $O_2$ and excreted $CO_2$. In this study, through the analysis of gas, we could explain the respiration of a fertile chicken egg during incubation.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.327-328
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• 2012

의료분야의 진단 방사선 장비는 초기의 필름방식 및 카세트에서 진보되어 현재는 디지털방식의 DR (Digital Radiography)이 널리 사용되며 이에 관한 연구개발이 활발히 진행 되고 있다. DR은 일반적으로 직접방식과 간접방식으로 나눌 수 있다. 직접방식의 원리는 X선을 흡수하면 전기적 신호를 발생 시키는 광도전체(Photoconductor)를 사용하여 광도전체 양단 전극에 전압을 인가하여 전기장을 유도한 가운데, X선을 조사하면 광도전체 내부에서 전자-전공쌍(Electron-hole pair)이 생성된다. 이것은 양단에 유도된 전기장의 영향으로 전자는 +극으로, 전공은 -극으로 이동하여 아래에 위치한 하부기판을 통하여 이미지로 변조된다. 간접방식은 X선을 흡수하면 가시광선으로 전환하는 형광체(Scintillator)를 사용하여 조사된 X선을 형광체에서 가시광선으로 전환하고, 이를 Photodiode와 같은 광변환소자로 전기적 신호로 변환하여 방사선을 검출하는 방식을 말한다. 본 연구에서는 직접방식에서 이용되는 광도전체 중 흡수효율이 높고 Mobility가 뛰어난 CdTe를 선정하여 PVD (Physical vapor deposition)방식으로 300 m의 두께를 목표로 하여 증착을 진행하였다. Chamber의 진공도가 $2.5{\times}10^{-2}$ Torr로 도달 시점부터, Substrate와 Boat에 열을 가하였다. Substrate온도는 $350^{\circ}C$, Boat온도는 $300^{\circ}C$도로 설정하여 11시간 동안 진행하였다. Substrate온도는 $303^{\circ}C$, Boat온도는 $297^{\circ}C$도부터 증착이 시작되어 선형적인 증가세 추이를 나타내어 Substrate 및 Boat온도가 설정 값에 도달 하였을 때, $25{\sim}34.4{\AA}/s$ 증착율을 나타내었다. 하부전극의 물질에 따른 CdTe증착 효율성 평가를 진행한 후, 그에 따른 전기적 특성을 알아보았다. 하부전극의 물질로는 ITO (Indium Tin Oxide), Parylene이 코팅 된 ITO, Au, Ag를 사용하였다. 하부전극의 물질 상단에 Thermal Evaporation System을 사용하여 CdTe를 증착한 후, Cdte 상단에 Au를 증착 시켜 민감도(Sensitivity)와 암전류(Dark current)를 측정하였다. 증착 결과 ITO와 Ag상단에 증착시킨 CdTe박막은 박리가 되었고, Au와 Parylene이 코팅 된 ITO에는 CdTe박막이 안정적이게 형성이 되었다. 이 두 샘플에 대하여 동일한 조건으로 민감도와 암전류를 측정 시, Parylene이 코팅된 ITO를 하부전극으로 사용한 CdTe박막은 0.1021 pA/$cm^2$의 암전류와 1.027 pC/$cm^2$의 민감도를 나타낸 반면, Au를 하부전극으로 사용한 CdTe박막은 0.0381 pA/$cm^2$의 암전류와 1.214 pC/$cm^2$의 민감도를 나타내어 Parylene이 코팅된 ITO보다 우수한 전기적 특성을 나타내었다. 따라서 Au는 CdTe박막 증착 시, 하부전극 기판으로서 뛰어난 특성을 나타내는 것을 알 수 있었다.

• Korean Journal of Environment and Ecology
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• v.34 no.3
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• pp.216-223
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• 2020

This study investigated the ecological characteristics of Coreoperca herzi at Jaho stream from September 2018 to August 2019. This species inhabited riffle and midstream of the stream, where the riverbed structure was mostly covered with cobble and pebble. The depth of the habitat was 32-157 cm, and the velocity of stream fast at 0.64±0.28 (0.32-1.28) m/sec. The gender ratio of females to males was 1:0.95. The age according to the frequency analysis of total length indicated that the group with 42-80 mm in total length was one year old, the group with 80-130 mm was two years old, the group with130-200 mm was three years old, and the group over 200 mm was four years old. The total length of sexually mature fishes was 65 mm for females and 70 mm for males. The sexually mature individuals grown in nature had a smaller total length than those reared in a laboratory. The spawning season was from May to late July, and the water temperature was 18.4-26.4℃ during the period. The prosperous spawning season was from May to June, and the water temperature was 18.4-21.8℃ during the period. The average number of eggs in the ovaries was 462 (151-919) per mature female, and the matured eggs were yellowish and spherical with a mean diameter of 2.31±0.33 (1.93-3.10) mm. Calculation length-weight relation of Korean aucha perch showed the constant a as 0.00002 and b as 3.01, condition factor (K) as 1.76 (1.01-2.63) on average, and the slope was a positive value of 0.0005.