• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.252-252
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• 2017

Nowadays water shortage is becoming one of the biggest problems in the Korea. Many different methods are developed for conservation of water. Soil water management has become the most indispensable factor for augmenting the crop productivity especially on soybean (Glycine max L.) because of their high susceptibility to both water stress and water logging at various growth stages. The farmers have been using irrigation techniques through manual control which farmers irrigate lands at regular intervals. Automatic irrigation systems are convenient, especially for those who need to travel. If automatic irrigation systems are installed and programmed properly, they can even save you money and help in water conservation. Automatic irrigation systems can be programmed to provide automatic irrigation to the plants which helps in saving money and water and to discharge more precise amounts of water in a targeted area, which promotes water conservation. The objective of this study was to determine the possible effect of automatic irrigation systems based on soil moisture on soybean growth. This experiment was conducted on an upland field with sandy loam soils in Department of Southern Area Crop, NICS, RDA. The study had three different irrigation methods; sprinkle irrigation (SI), surface drip irrigation (SDI) and fountain irrigation (FI). SI was installed at spacing of $7{\times}7m$ and $1.8m^3/hr$ as square for per irrigation plot, a lateral pipe of SDI was laid down to 1.2 m row spacing with $2.3L\;h^{-1}$ discharge rate, the distance between laterals was 20 cm spacing between drippers and FI was laid down in 3m interval as square for per irrigation plot. Soybean (Daewon) cultivar was sown in the June $20^{th}$, 2016, planted in 2 rows of apart in 1.2 m wide rows and distance between hills was 20 cm. All agronomic practices were done as the recommended cultivation. This automatic irrigation system had valves to turn irrigation on/off easily by automated controller, solenoids and moisture sensor which were set the reference level as available soil moisture levels of 30% at 10cm depth. The efficiency of applied irrigation was obtained by dividing the total water stored in the effective root zone to the applied irrigation water. Results showed that seasonal applied irrigation water amounts were $60.4ton\;10a^{-1}$ (SI), $47.3ton\;10a^{-1}$ (SDI) and $92.6 ton\;10a^{-1}$ (FI), respectively. The most significant advantage of SDI system was that water was supplied near the root zone of plants drip by drip. This system saved a large quantity of water by 27.5% and 95.6% compared to SI, FI system. The average soybean yield was significantly affected by different irrigation methods. The soybean yield by different irrigation methods were $309.7kg\;10a^{-1}$ from SDI $282.2kg\;10a^{-1}$ from SI, $289.4kg\;10a^{-1}$ from FI, and $206.3kg\;10a^{-1}$ from control, respectively. SDI resulted in increase of soybean yield by 50.1%, 7.0% 9.8% compared to non-irrigation (control), FI and SI, respectively. Therefore, the automatic irrigation system supplied water only when the soil moisture in the soil went below the reference. Due to the direct transfer of water to the roots water conservation took place and also helped to maintain the moisture to soil ratio at the root zone constant. Thus the system is efficient and compatible to changing environment. The automatic irrigation system provides with several benefits and can operate with less manpower. In conclusion, improving automatic irrigation system can contribute greatly to reducing production costs of crops and making the industry more competitive and sustainable.

• Journal of Animal Environmental Science
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• v.18 no.3
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• pp.207-220
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• 2012

There are around 7,500 manure tanks to treat the manures from pigs in Korea. In the tank, there are too much sediments deposited on the base and wall, which causes low efficiency of stock capacity and manure fermentation. In order to minimize sediments and to ferment manure effectively, we developed a 2-fluid jet mixer for mixing sediments in liquid livestock manure tank. For developing the prototype, we tested a factorial experimental system with various nozzles, and simulated CFD models with two kinds of nozzle arrangement. From the results of factorial experiment and CFD simulation, we concluded the dia. ratio of primary : secondary nozzle should be 1:2 and the nozzles should be arranged at the same distances toward to the circumferential direction. With this results, we manufactured a 2-fluid jet mixer which is consists of four 2-phase nozzles, centrifugal slurry pump and root's type air blower. And, we carried out the performance test of the prototype in the round shaped liquid manure tank in the farm. The performance test results showed that the uniformity of TS (Total Solid) and VS (Volatile Solid) was raised from 21.3 g/L, 13.3 g/L In steady state to TS and VS to 23.0 g/L, 14.1 g/L in the mixing operation. Therefore, we could conclude that the prototype of 2-fluid mixer could make the solid material which could be sediments in the tank not to be deposited in the tank and to be contacted to air bubbles which could enhance the efficiency of the fermentation of livestock manure.

• Applied Microscopy
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• v.38 no.3
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• pp.175-183
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• 2008

Liver regeneration is a result of highly coordinated proliferation of hepatocytes and non-parenchymal liver cells. At this process, induction of metallothionein (MT), which is low molecular and cysteine rich, has been reported. The present study was carried to find the ultrastructure of hepatocytes and determine the expression of MT in regenerating rat liver after partial hepatectomy. As a result, the remnant liver after PH grew fast from 1 day until 7 days. Various changes were morphologically observed. Disintegration of cell plates and liver lobule appeared shortly after PH. And hepatocytes showed the rapid proliferation, characterized by high nuclear cytoplasmic ratio, weak intercellular junctional complexes, chromatin condensation, increase of ribosomes and mitochondria, and temporary increase of lipid droplets. Finally, remodeling of the liver lobule was completed through the rearrangement of blood vessels and cell plates by 7 days after PH. On histochemistry, immunoreactivity indicating the presence of MT appeared moderately throughout the cytoplasm of control rat hepatocyte. After PH, positive reactions for MT increased at the cytoplasm and the nucleus. These results suggest that the remnant liver cells immediately entered cell proliferation and increase of MT expression after PH. It is thought that MT protein might be associated with transfer of some factors needed to cell division from the cytoplasm to the nucleus for regeneration of the liver after PH.

• International Journal of Highway Engineering
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• v.1 no.1
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• pp.107-119
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• 1999

The joints in the jointed concrete pavement provide a control against transverse or longitudinal cracking at slab, which may be caused by temperature or moisture variation during or after hydration. Without control of cracking, random cracks cause more serious distresses and result in structural or functional failure of pavement system. However, joints nay cause distresses due to its inherent weakness in structural integrity. Thus, the evaluation at joint is very important. and the joint-related distresses should be evaluated reasonably for economic rehabilitation. The purpose of this paper was to develop an evaluation system at joints of jointed concrete pavement using finite element analysis program, ILLI-SLAB, and nondestructive testing device. FWD. To develop an evaluation system for JCP, a sensitivity analysis was performed using ILLI-SLAB program with a selected variables which might affect fairly to on the performance of transverse joints. The most significant variables were selected from precise analysis. An evaluation charts were made for jointed concrete pavement by adopting the field FWD data. It was concluded that the variables which most significantly affect to pavement deflections are the modulus of subgrade reaction(K) and the modulus of dowel/concrete interaction(G), and limiting criteria on the performance of joints at JCP are 300pci. 500,000 lb/in. respectively. Using these variables and FWD test, a charts of load transfer ratio versus surface deflection at joints were made in order to evaluate the performance of JCP. Practically, Chungbu highway was evaluated by these evaluation charts and FWD field data for jointed concrete pavement. For Chungbu highway, only one joint showed smaller value than limiting criterion of the modulus of dowel/concrete interaction(G). The rest joints showed larger values than limiting criteria of the modulus of subgrade reaction(K) and the modulus of dowel/concrete interaction(G).

• Journal of Food Hygiene and Safety
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• v.26 no.4
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• pp.315-321
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• 2011

This study was performed to investigate contamination levels of aflatoxins, the secondary metabolites produced by fungi Aspergillus flavus and A. parasiticus, in herbal medicine. Herbs is susceptible to these fungi infections through its growth harvest, transport and storage. This study determine the aflatoxin $B_1$, $B_2$, $G_1$ and $G_2$ levels by HPLC-florescence detector coupled with photochemical enhancement in 558 samples herbal medicine distributed in Korea and China. Also, We checked a transfer ratio of aflatoxins from raw herbal medicines to herbal medicine extract. Hot water extraction of herbal medicines was prepared by air pressure and high pressure condition. The analytical method for aflatoxins was validated in this method. In results recoveries of the analytical method were ranged from 67.4% to 96.2% and, limits of detection and quantitation for aflatoxins were $0.015{\sim}0.138\;{\mu}g/kg$ and $0.046{\sim}0.418\;{\mu}g/kg$, respectively. According to the results of monitoring on aflatoxins in herbal medicine, aflatoxins 1.7 ug/kg $B_1$ and 0.9 ug/kg $G_1$ were detected in only one sample of Strychni Ignatii Semen, and 0.8 ug/kg $G_1$ in Strychni Semen. About 13.6~51.3% of aflatoxins were transferred to hot water extract. Although the detected levels are under the permitted levels for aflatoxins in herbal medicine, these amounts should be considered in regard to overall daily exposure to mycotoxins.

• Progress in Medical Physics
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• v.26 no.1
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• pp.28-35
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• 2015

In this study, we investigated the effects of an iterative reconstruction algorithm and an automatic exposure control (AEC) technique on image quality and radiation dose through phantom experiments with coronary computed tomography (CT) angiography protocols. We scanned the AAPM CT performance phantom using 320 multi-detector-row CT. At the tube voltages of 80, 100, and 120 kVp, the scanning was repeated with two settings of the AEC technique, i.e., with the target standard deviations (SD) values of 33 (the higher tube current) and 44 (the lower tube current). The scanned projection data were reconstructed also in two ways, with the filtered back projection (FBP) and with the iterative reconstruction technique (AIDR-3D). The image quality was evaluated quantitatively with the noise standard deviation, modulation transfer function, and the contrast to noise ratio (CNR). More specifically, we analyzed the influences of selection of a tube voltage and a reconstruction algorithm on tube current modulation and consequently on radiation dose. Reduction of image noise by the iterative reconstruction algorithm compared with the FBP was revealed eminently, especially with the lower tube current protocols, i.e., it was decreased by 46% and 38%, when the AEC was established with the lower dose (the target SD=44) and the higher dose (the target SD=33), respectively. As a side effect of iterative reconstruction, the spatial resolution was decreased by a degree that could not mar the remarkable gains in terms of noise reduction. Consequently, if coronary CT angiogprahy is scanned and reconstructed using both the automatic exposure control and iterative reconstruction techniques, it is anticipated that, in comparison with a conventional acquisition method, image noise can be reduced significantly with slight decrease in spatial resolution, implying clinical advantages of radiation dose reduction, still being faithful to the ALARA principle.

• Korean Journal of Animal Reproduction
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• v.25 no.2
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• pp.119-124
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• 2001

This study was performed to investigate the effects of the peptide to carrier ratio on the immune and biological functions to inhibin immunization in Hanwoo. A peptide sequence kom the alpha -subunit (19~32 peptide) of porcine inhibin was synthesized for antigen and conjugated to human serum albumin(HSA) for carrier protein. Anti-inhibin sera(AI) were produced 52 day later from rabbit after injection of inhibin-$\alpha$ -subunit peptide conjugator for antigen with the interval of 2 weeks. Immune-blotting analysis using antibody specific fur inhibin-$\alpha$ subunits revealed that the inhibin was detected at 1.0 cm bovine follicular fluid(bFF). However, each stage of corpus lutea and 0.1 cm of follicular fluid were not detected. The maximal contents of estradiol-17 $\beta$ in Hanwoo ovarian follicular fluid were detected at 2.0 cm of follicular size(diameter), but the mean total contents of these hormone decreased significantly with decreasing diameter of follicles. However, progesterone contents of follicular fluid were high at 1.0 cm of follicle. Progesterone secretion by Hanwoo granulosa cell cultured for 48 hr in vitro was significantly (p＜0.05) inhibited in 5% bFF and 5% bFF + 5% AI addition group compared with control group. Estradiol-17 $\beta$ secretion by Hanwoo granulosa cell cultured for 48 hr in vitro was significantly (p＜0.05) increased in 5% AI and 5% AI + 5% bFF addtion group compared with control group. However, the groups added 5% AI were not changed compared to control groups in progesterone and estradiol-17 $\beta$. Taken together, we suggested that inhibin in the mature FF plays a pivotal role on the biosynthesis of steroid hormone of follicular cells during follicular development.

• The Journal of the Korean Society for Microbiology
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• v.14 no.1
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• pp.27-37
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• 1979

Ninety-five strains of Shigella, 70 of Salmonella paratyphi A, and 230 of Salmonella typhi were tested for their resistance to drugs. Also studied was the inhibition and elimination of drug resistance. All except one strain of Shigella consisted of 79 Sh. flexneri and 16 Sh. sonnei were multiply resistant to chloramphenicol, tetracycline, streptomycin, and splfisomidine. Among them, 70 strains were resistant to ampicillin and carbenicillin, 80 to trimethoprim-sulfamethoxazole, 22 to nalidixic acid, and one to kanamycin, but strain resistant to gentamicin, cephaloridine, and rifampin was not encountered. All strains of S. paratyphi A and S. typhi were susceptible to drugs tested, except sulfisomidine and rifampin, for which all S. paratyphi A were slightly resistant to sulfisomidine and the majority of S. paratyphi A and S. typhi were slightly resistant to rifampin. Approximately 80% of multiply drug-resistant Shigella transferred their resistance to E. coli by conjugation, and the resistance was considered to be mediated by R plasmids. The frequency of transfer of drug resistance varied by donor strains and recipients, but not by selecting drugs. Resistance to nalidixic acid was not transferred by conjugation to the recipients. Drug-resistant Shigella strains successively subcultured in nutrient agar stabs contained clones resistant to drugs and those susceptible to drugs, but the ratio of resistant and susceptible clones varied by strains. The multiply drug-resistant S. typhi and Shigella strains were found to not lose completely their drug resistance by subculture in media. Acriflavine has some effect on the elimination of drug resistance mediated by R plasmids, but the effect varied markedly by strains. Atabrine has no effect among strains tested. The combination of drugs increased the drug actions in majority of cases with synergistic or additive effects.

• Korean Journal of Food Science and Technology
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• v.12 no.3
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• pp.170-175
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• 1980

A mass production of chestnut necessiates the development of economic long-term storage method. The main objective of this study was to confirm the technical aspect of the chestnut storage method which was developed by two year project and to review the method of commercial application. The chestnut used for the experiments were separated in brine $(5.5{\sim}6.0^{\circ}\:B{\acute{a}}ume)$ into matured and unmatured lots and fumigated with $CS_2$ at a 5 $lb/27\;m^3$ level for $25{\sim}30\;hrs.$ The chestnuts were packed in wooden boxes with sawdust (50% moisture) in the ratio of 1 : 1 by volume. The boxes were stored in the cold room $(1{\pm}1^{\circ}C,\;85{\sim}95%\;RH)$ and the cellar ($0{\sim}10^{\circ}C$, controlled only by circulating night cool air). The results obtained were as follows: 1. Fully matured chestnut could be successfully preserved $8{\sim}9\;months$ at a l0% decay level in the cold room and $4{\sim}5\;months$ months in cellar. 2. Immatured chestnuts wire inferior to the matured in storage stability. At the maximum storage period, its storage life was two months shorter. 3. The heat transfer equation of piled chestnuts with sawdust can be suggested as $T_{\infty}-T_0=(T_{\infty}-T_0){\cdot}10^{-t/320}$ and j and $f_h$ values were 1 and 320 min, respectively. 4. The chestnuts in the package of storage unit had longer shelf life than naked chestnut during the retail distribution at ambient temperature.

• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.27-32
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• 2010

This study was conducted to monitor aflatoxins in various medicinal herbs, providing available data for the safety of those products. To monitor aflatoxins in medicinal herbs, a total of 400 samples of 40 different herbs were collected in commercial retailers in Seoul, Daejeon, Gwangju, Daegu, and Busan from March to August, 2008. The samples that passed the sensory evaluation were tested for aflatoxins. Aflatoxins in samples were analyzed by HPLC-florescence coupled with photochemical enhancement. Samples were extracted with 70% methanol and then diluted to the appropriate concentration. A refining process was performed using an immunoaffinity column. The analytical method used in this study was validated. The $R^2$ value for aflatoxin $B_1$ was 0.99946, and the detection range was from 0.25 to 10.0 ng/mL. The accuracy of the analysis was ranged from 83.2% to 101.8%. The relative standard deviation (RSD) in the aflatoxin $B_1$ analysis was 3.4%, demonstrating the precision of this method. In addition, the detection limit and quantitative analysis limit of aflatoxin $B_1$ was $0.53\;{\mu}g/kg$ and $1.76\;{\mu}g/kg$, respectively. These results indicated that the analytical method used in this study was appropriate. The results of HPLC showed that 1% (4 samples) of the samples may contain aflatoxins. The concentration of quantified aflatoxin was $2.3\;{\mu}g/kg$ for both Quisqualis fructus and Remotiflori radix samples. The other samples were below the limit of quantification. Moreover, the concentration of aflatoxin $B_1$ which is made by specific fungi were below the level of regulation. Only 20% of aflatoxin $B_1$ were transferred to hot water. Therefore, the levels of aflatoxins in medicinal herbs were considered to be safe especially considering the aflatoxin transfer ratio.