• Title/Summary/Keyword: Low-flow

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Low Temperature Growth of MCN(M=Ti, Hf) Coating Layers by Plasma Enhanced MOCVD and Study on Their Characteristics (플라즈마 보조 유기금속 화학기상 증착법에 의한 MCN(M=Ti, Hf) 코팅막의 저온성장과 그들의 특성연구)

  • Boo, Jin-Hyo;Heo, Cheol-Ho;Cho, Yong-Ki;Yoon, Joo-Sun;Han, Jeon-G.
    • Journal of the Korean Vacuum Society
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    • v.15 no.6
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    • pp.563-575
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    • 2006
  • Ti(C,N) films are synthesized by pulsed DC plasma enhanced chemical vapor deposition (PEMOCVD) using metal-organic compounds of tetrakis diethylamide titanium at $200-300^{\circ}C$. To compare plasma parameter, in this study, $H_2$ and $He/H_2$ gases are used as carrier gas. The effect of $N_2\;and\;NH_3$ gases as reactive gas is also evaluated in reduction of C content of the films. Radical formation and ionization behaviors in plasma are analyzed in-situ by optical emission spectroscopy (OES) at various pulsed bias voltages and gas species. He and $H_2$ mixture is very effective in enhancing ionization of radicals, especially for the $N_2$. Ammonia $(NH_3)$ gas also highly reduces the formation of CN radical, thereby decreasing C content of Ti(C, N) films in a great deal. The microhardness of film is obtained to be $1,250\;Hk_{0.01}\;to\;1,760\;Hk_{0.01}$ depending on gas species and bias voltage. Higher hardness can be obtained under the conditions of $H_2\;and\;N_2$ gases as well as bias voltage of 600 V. Hf(C, N) films were also obtained by pulsed DC PEMOCYB from tetrakis diethyl-amide hafnium and $N_2/He-H_2$ mixture. The depositions were carried out at temperature of below $300^{\circ}C$, total chamber pressure of 1 Torr and varying the deposition parameters. Influences of the nitrogen contents in the plasma decreased the growth rate and attributed to amorphous components, to the high carbon content of the film. In XRD analysis the domain lattice plain was (111) direction and the maximum microhardness was observed to be $2,460\;Hk_{0.025}$ for a Hf(C,N) film grown under -600 V and 0.1 flow rate of nitrogen. The optical emission spectra measured during PEMOCVD processes of Hf(C, N) film growth were also discussed. $N_2,\;N_2^+$, H, He, CH, CN radicals and metal species(Hf) were detected and CH, CN radicals that make an important role of total PEMOCVD process increased carbon content.

Purification Characteristics and Hydraulic Conditions in an Artificial Wetland System (인공습지시스템에서 수리학적 조건과 수질정화특성)

  • Park, Byeng-Hyen;Kim, Jae-Ok;Lee, Kwng-Sik;Joo, Gea-Jae;Lee, Sang-Joon;Nam, Gui-Sook
    • Korean Journal of Ecology and Environment
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    • v.35 no.4 s.100
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    • pp.285-294
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    • 2002
  • The purpose of this study was to evaluate the relationships between purification characteristics and hydraulic conditions, and to clarify the basic and essential factors required to be considered in the construction and management of artificial wetland system for the improvement of reservoir water quality. The artificial wetland system was composed of a pumping station and six sequential plants beds with five species of macrophytes: Oenanthe javanica, Acorus calamus, Zizania latifolia, Typha angustifolia, and Phragmites australis. The system was operated on free surface-flow system, and operation conditions were $3,444-4,156\; m^3/d$ of inflow rate, 0.5-2.0 hr of HRT, 0.1-0.2 m of water depth, 6.0-9.4 m/d of hydraulic loading, and relatively low nutrients concentration (0.224-2.462 mgN/L, 0.145-0.164 mgP/L) of inflow water. The mean purification efficiencies of TN ranged from 12.1% to 14.3% by showing the highest efficiency at the Phragmites australis bed, and these of TP were 6.3-9.5% by showing the similar ranges of efficiencies among all species. The mean purification efficiencies of SS and Chl-A ranged from 17.4% to 38.5% and from 12.0% to 20.2%, respectively, and the Oenanthe javanica bed showed the highest efficiency with higher concentration of influent than others. The mean purification amount per day of each pollutant were $9.8-4.1\;g{\cdot}m^{-2}{\cdot}d^{-1}$ in BOD, $1.299-2.343\;g{\cdot}m^{-2}{\cdot}d^{-1}$ in TN, $0.085-1.821\;g{\cdot}m^{-2}{\cdot}d^{-1}$ in TP, $17.9-111.6\;g{\cdot}m^{-2}{\cdot}d^{-1}$ in SS and $0.011-0.094\;g{\cdot}m^{-2}{\cdot}d^{-1}$ in Chl-a. The purification amount per day of TN revealed the hi링hest level at the Zizania latifolia bed, and TP showed at the Acrous calamus bed. SS and Chl-a, as particulate materials, revealed the highest purification amount per day at the Oenanthe javanica bed that was high on the whole parameters. It was estimated that the purification amount per day was increased with the high concentration of influent and shoot density of macrophytes, as was shown in the purification efficiency. Correlation coefficients between purification efficiencies and hydraulic conditions (HRT and inflow rate) were 0.016-0.731 of $R^2$ in terms of HRT, and 0.015-0.868 of $R^2$ daily inflow rate. Correlation coefficients of purification amounts per day with hydraulic conditions were 0.173-0.763 of Ra in terms of HRT, and 0.209-0.770 daily inflow rate. Among the correlation coefficients between purification efficiency and hydraulic condition, the percentages of over 0.5 range of $R^2$ were 20% in HRT and in daily inflow rate. However, the percentages of over 0.5 range of correlation coefficients ($R^2$) between purification amount per day and hydraulic conditions were 53% in HRT and 73% in daily inflow rate. The relationships between purificationamount per day and hydraulic condition were more significant than those of purifi-cation efficiency. In this study, high hydraulic conditions (HRT and inflow rate) are not likely to affect significantly the purification efficiency of nutrient. Therefore, the emphasis should be on the purification amounts per day with high hydraulicloadings (HRT and inflow rate) for the improvement of eutrophic reservoir withrelatively low nutrients concentration and large quantity to be treated.

Edge to Edge Model and Delay Performance Evaluation for Autonomous Driving (자율 주행을 위한 Edge to Edge 모델 및 지연 성능 평가)

  • Cho, Moon Ki;Bae, Kyoung Yul
    • Journal of Intelligence and Information Systems
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    • v.27 no.1
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    • pp.191-207
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    • 2021
  • Up to this day, mobile communications have evolved rapidly over the decades, mainly focusing on speed-up to meet the growing data demands of 2G to 5G. And with the start of the 5G era, efforts are being made to provide such various services to customers, as IoT, V2X, robots, artificial intelligence, augmented virtual reality, and smart cities, which are expected to change the environment of our lives and industries as a whole. In a bid to provide those services, on top of high speed data, reduced latency and reliability are critical for real-time services. Thus, 5G has paved the way for service delivery through maximum speed of 20Gbps, a delay of 1ms, and a connecting device of 106/㎢ In particular, in intelligent traffic control systems and services using various vehicle-based Vehicle to X (V2X), such as traffic control, in addition to high-speed data speed, reduction of delay and reliability for real-time services are very important. 5G communication uses high frequencies of 3.5Ghz and 28Ghz. These high-frequency waves can go with high-speed thanks to their straightness while their short wavelength and small diffraction angle limit their reach to distance and prevent them from penetrating walls, causing restrictions on their use indoors. Therefore, under existing networks it's difficult to overcome these constraints. The underlying centralized SDN also has a limited capability in offering delay-sensitive services because communication with many nodes creates overload in its processing. Basically, SDN, which means a structure that separates signals from the control plane from packets in the data plane, requires control of the delay-related tree structure available in the event of an emergency during autonomous driving. In these scenarios, the network architecture that handles in-vehicle information is a major variable of delay. Since SDNs in general centralized structures are difficult to meet the desired delay level, studies on the optimal size of SDNs for information processing should be conducted. Thus, SDNs need to be separated on a certain scale and construct a new type of network, which can efficiently respond to dynamically changing traffic and provide high-quality, flexible services. Moreover, the structure of these networks is closely related to ultra-low latency, high confidence, and hyper-connectivity and should be based on a new form of split SDN rather than an existing centralized SDN structure, even in the case of the worst condition. And in these SDN structural networks, where automobiles pass through small 5G cells very quickly, the information change cycle, round trip delay (RTD), and the data processing time of SDN are highly correlated with the delay. Of these, RDT is not a significant factor because it has sufficient speed and less than 1 ms of delay, but the information change cycle and data processing time of SDN are factors that greatly affect the delay. Especially, in an emergency of self-driving environment linked to an ITS(Intelligent Traffic System) that requires low latency and high reliability, information should be transmitted and processed very quickly. That is a case in point where delay plays a very sensitive role. In this paper, we study the SDN architecture in emergencies during autonomous driving and conduct analysis through simulation of the correlation with the cell layer in which the vehicle should request relevant information according to the information flow. For simulation: As the Data Rate of 5G is high enough, we can assume the information for neighbor vehicle support to the car without errors. Furthermore, we assumed 5G small cells within 50 ~ 250 m in cell radius, and the maximum speed of the vehicle was considered as a 30km ~ 200 km/hour in order to examine the network architecture to minimize the delay.

Study on the Anti-cancer, Anti-metastasis and Immune response improvement Effects of Aqua-acupuncture with Rubi Fructus infusion solution (항암(抗癌) 및 면역효과(免疫效果)에 복분자약침(覆盆子藥鍼)이 미치는 영향(影響))

  • Lee, Seon-Hee;Lee, Byung-Ryul
    • Journal of Acupuncture Research
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    • v.17 no.1
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    • pp.189-219
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    • 2000
  • To study the effects of anti-cancer, anti-metastasis and immune response improvement effects of aqua-acupuncture with Rubi Fructus infusion solution, we used Rubi Fructus infusion solution(taken by water-alcohol method) put into Chung-wan (CV12) and Chok-Samni(ST36) of BALB/c or C57BL/6 which are corresponding to humanbody. We observed the cytotoxicity, the effect on the expression of MMP-9 gene, the ability to control cancer cell proliferation, change of body weight, surviving number, median surviving time, increase of life span, changes in amount of leukocyte, erythrocyte, platelet, total protein, creatinine, glucose and LDH, weight of spleen, number of pulmonary colony, histological analysis on tissue metastasis of lung and liver, splenic cell proliferation, the expression of cytokine gene, the number of $CD4^+$, $CD8^+$, $CD19^+$ and NK cell, and concluded like this. The results were obtained as follows : 1. Effects of Anti-cancer 1) The cytotoxicity about B16-F10 cell line of $2^0$, $2^{-1}$, $2^{-2}$, $2^{-3}$, $2^{-5}$, $2^{-6}$, $2^{-7}$, $2^{-8}$ diluent groups in Rubi Fructus infusion solution treatment was inhibited significantly, compared with control group. 2) The cytotoxicity about HT1080 cell line of $2^0{\sim}2^{-8}$ diluent groups in Rubi Fructus infusion solution treatment was inhibited significantly, compared with control group. 3) The effect on expression of MMP-9 gene was inhibited significantly in all the sample groups, compared with control group. 4) The effect on the control-ability on the cancer cell proliferation showed cytotoxicity significantly in $2^0$, $2^{-1}$, $2^{-2}$, $2^{-3}$, $2^{-4}$, $2^{-5}$, $2^{-6}$, $2^{-7}$, diluent groups. 2. Effects of Anti-metastasis 1) S-180 cancer cell line transplants in BALB/c mice were inhibited significantly in weight increase in all the sample groups, compared with control group. The surviving number increased in almost sample groups, except one group put into Chok-Samni(ST36) with 20% Rubi Fructus infusion solution treatment group that showed same number of the control group. 2) S-180 cancer cell line transplants in BALB/c mice showed high MST significantly in almost sample groups, compared with control group. But one group put into Chok-Samni(ST36) with 20% Rubi Fructus infusion solution showed low MST than control group. 3) The group injected in vein with B16-F10 cancer cell line in C57BL/6 mice showed increased ILS than control group significantly in anti-metastasis test. 3. Effects of Immune response improvement 1) The group injected in vein with B16-F10 cancer cell line in C57BL/6 mice were increased significantly in the number of leukocyte and glucose, and decreased significantly in the amount of platelet and LDH, compared with control group. However, there's no significant increase or decrease in number of erythrocyte, total protein and creatinine. 2) We couldn't find any significant relation in spleen weight of the sample group. 3) In pulmonary colony, sample group was decreased significantly, compared with control group. 4) Histological analysis of sample group inhivited compared with that of control group in both of lung and liver. 5) In immune system, all the sample groups showed having more relevancy to the effect on splenic cell proliferation than normal group. 6) Cytokine gene increased in almost sample groups, except one group treated with $50{\mu}g/m{\ell}$ Rubi Fructus infusion solution on IL-12. 7) In flow cytometry there's no significant relation in number of $CD8^+$ cell, however, the number of $CD4^+$, $CD19^+$ cell and NK cell in sample group had more relation than in control group. Above the results showed that aqua-acupuncture of Rubi Fructus solution has effects of anti-cancer, and-metastasis and immune response improvement.

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Study on the Anti-cancer, Anti-metastasis and Immune response improvement of Aqua-acupuncture with Cistanches Herba infusion solution (육종용약침의 항암작용(抗癌作用) 및 면역효과(免疫效果)에 대(對)한 실험적(實驗的) 연구(硏究))

  • Lee, Eun-Yong;Lee, Byung-Ryul
    • Journal of Acupuncture Research
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    • v.17 no.1
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    • pp.251-286
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    • 2000
  • To study the effects of anti-cancer, anti-metastasis and immune response improvement of aqua-acupuncture with Cistanches Herba infusion solution, we used Cistanches Herba infusion solution(taken by water-alcohol method) put into Chung-wan(CV12) and Chok-Samni(S36) of BALB/c or C57BL/6 which are corresponding to human body. We observed the cytotoxicity, the effect on the expression of MMP-9 gene, the ability to control cancer cell proliferation, change of body weight, surviving number, MST, ILS, changes in amount of WBC, RBC, PLT, total protein, creatinine, glucose and LDH, weight of spleen, number of pulmonary colony, histological analysis on tissue metastasis of lung and liver, splenic cell proliferation, the expression of cytokine gene, the number of $CD4^+$, $CD8^+$, $CD19^+$ and NK cell, and concluded like this. The results were obtained as follows : 1. The cytotoxicity about B16-F10 cell line of $2^0$, $2^{-1}$, $2^{-2}$, $2^{-5}$ diluent groups in Cistanches Herba infusion solution treatment was inhibited significantly, compared with control group. 2. The cytotoxicity about HT1080 cell line of $2^0$, $2^{-1}$, $2^{-2}$, $2^{-3}$, $2^{-5}$, $2^{-8}$ diluent groups in Cistanches Herba infusion solution treatment was inhibited significantly, compared with control group. 3. The effect on expression of MMP-9 gene was decreased in all the sample groups, compared with control group. 4. The effect on the control-ability on the cancer cell proliferation showed cytotooicity significantly in $2^0$, $2^{-1}$, $2^{-2}$, $2^{-3}$, $2^{-4}$, $2^{-5}$ diluent groups. 5. S-180 cancer cell line transplants in BALB/c mice were inhibited significantly in weight increase in all the sample groups, compared with control group. The surviving number increased in almost sample groups, except one group put into Chok-Samni(S36) with 20% Cistanches Herba infusion solution treatment group that showed same number of the control group. 6. S-180 cancer cell line transplants in BALB/c mice showed high MST and ILS significantly in almost sample groups, compared with control group. But one group put into Chok-Samni(S36) with 20% Cistanches Herba infusion solution treatment group showed low MST and ILS than control group. 7. The sample group injected in vein with B16-F10 cancer cell line in C57BL/6 mice showed increased ILS compared with control group significantly in anti-metastasis test. 8. The sample group injected in vein with B16-F10 cancer cell line in C57BL/6 mice were increased significantly in the number of WBC and glucose, and decreased significantly in the amount of LDH, compared with control group. However, there's no significant increase or decrease in number of RBC, PLT, total protein and creatinine. 9. We couldn't find any significant relation in spleen weight of the sample group. 10. In pulmonary colony, sample group was decreased significantly, compared with control group. 11. Histological analysis of sample group inhivited compared with that of control group in both of lung and liver. 12. In immune system, all the sample groups showed having more relevancy to the effect on splenic cell proliferation than normal group. 13. The effect on cytokine gene expression of all the sample groups were increased than control group. 14. In flow cytometry there's no significant relation in number of $CD8^+$, $CD19^+$ cell, however, the number of $CD4^+$ cell and NK cell in sample groups were increased than in control group. Above the results showed that aqua-acupuncture of Cistanches Herba infusion solution has effects of anti-cancer, anti-metastasis and immune response improvement.

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Study on the Biodegradability of Dispersants and Dispersant/Bunker-C Oil Mixtures and the Dissolved Oxygen Consumption in the Seawater(I) - The Biodegradability of Dispersants and the Dissolved Oxygen Consumption in the Seawater - (해수중에서 유처리제 및 유처리제/Bunker-C유 혼합물의 생분해도와 용존산소소비에 관한 연구(I) - 유처리제의 생분해도와 용존산소소비 -)

  • KIM Gwang-Su;PARK Chung-Kil;YOU Sun-Jae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.26 no.5
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    • pp.493-501
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    • 1993
  • As the dispersants and the dispersant/oil mixtures are degraded naturally by the microorganisms in the seawater, the consumption of dissolved oxygen may cause marine organisms to be damaged especially in the waters where the dissolved oxygen level is low due to the pollution and the restriction of seawater flow. The biodegradation experiment, the TOD analysis and the element analysis for three dispersants(SG, GL and WC) and a nonionic surfactant(OA-5) were conducted for the purposes of evaluating the biodegradability of dispersants and studying the effect of dispersants on dissolved oxygen in the seawater. The results of biodegradation experiment showed 1mg of dispersants to be equivalent to $0.403{\sim}0.595mg$ of $BOD_5$ and to $0.703{\sim}0.855mg$ of $BOD_{20}$, and 1mg of nonionic surfactant to be equivalent to 0.50mg of $BOD_5$ and to 0.97mg of $BOD_{20}$ in the natural seawater. The results of TOD analysis showed 1mg of dispersants to be $2.37{\sim}2.80mg$ of TOD and 1mg of nonionic surfactant to be 2.45mg of TOD. The results of element analysis showed carbon content and hydrogen content to be $67.6{\sim}76.5\%$ and $10.2{\sim}12.2\%$ for dispersants, and $65.3\%$ and $10.3\%$ for nonionic surfactant, respectively. No nitrogen element was detected in dispersants and a nonionic surfactant. The biodegradability of dispersants shown as the ratio of $BOD_5/TOD$ was found to be in the range of $17{\sim}21\%$, and that of nonionic surfactant was found to be about $20\%$. This means that dispersants and nonionic surfactant belong in the organic matter group of middle-biodegradabilily. The deoxygenation rates($K_1$) and ultimate oxygen demands($L_o$) obtained through the biodegration experiment and Thomas slope method were found to be $0.121{\sim}0.171/day$ and $3.155{\sim}3.810mg/l$ for 4mg/l of dispersants and to be 0.181/day and 1.911mg/l for 2mg/l of nonionic surfactant in the seawater, respectively.

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Assessment of Water Quality and Pollutant Loads on Agricultural Watershed in Jeonbuk Province (전북지역 농업용 하천유역의 수질과 부하량 특성)

  • Uhm, Mi-Jeong;Moon, Young-Hun;Ahn, Byung-Koo;Shin, Yong-Kyu
    • Korean Journal of Environmental Agriculture
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    • v.27 no.2
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    • pp.111-119
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    • 2008
  • This study was conducted to evaluate water quality and pollutant loads on small agricultural watershed in Jeonbuk province. The EC level of investigated watershed ranged from 0.07 to 0.52 dS/m, BOD level ranged from 0.1 to 5.0 mg/L, and $COD_{Cr}$ level ranged from 0.6 to 17.7 mg/L. As above, contents of water quality indicators covered wide range, but each indicator was alike in mean content every other year. The contents of EC, $Ca^{2+},\;Mg^{2+},\;K^+\;and\;Na^+$ were decreased in rainy season, but the contents of BOD, $COD_{Cr},\;COD_{Mn}$, T-N and T-P were not greatly different as compared to dry season. And high content of SS showed substantial sediments near the surface flow out and influence on water system in rainy season. The pollutant loads measured in terminal of watershed were $9.6{\sim}757.9$ kg/day for BOD, $51.2{\sim}1418.5$ kg/day for T-N and $0.3{\sim}44.7$ kg/day for T-P. The pollutant loads of BOD, T-N and T-P in rainy season increased several times as compared to dry season. In rainy season, watershed with more than 30% in the proportion of paddy field to land showed relatively low discharge and pollutant loads in comparison to watershed with less than 30%. The discharge of watershed in rainy season increased 5.7times compared with the dry season in watershed with less than 30% in the proportion of paddy field to land, whereas was only 2.3times in watershed with more than 30%. The correlation coefficient($R^2$) of regression between discharge and pollutant loads of T-N were higher than those of BOD and T-P.

Frequency of Spontaneous Polyploids in Monoembryonic Jeju Native Citrus Species and Some Mandarin Cultivars (단배성 제주 재래귤 및 만다린잡종에서 자연 발생적인 배수체의 발생 빈도)

  • Chae, Chi-Won;Yun, Su-Hyun;Park, Jae-Ho;Kim, Min-Ju;Koh, Sang-Wook;Song, Kwan-Jeong;Lee, Dong-Hun
    • Journal of Life Science
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    • v.22 no.7
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    • pp.871-879
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    • 2012
  • Polyploids are a potentially important germplasm source in seedless citrus breeding program. Seedlessness is one of the most promising traits of commercial mandarin breeds that mandarin triploid hybrids possess permanently. The formation of new constant triploid hybrids can be recovered through diploid species hybridization from the fusion of divalent gametes at low frequencyor intra-and inter-ploidy crosses. However, extensive breeding work based on small $F_1$ hybrid seeds developed is impossible without a very effective aseptic methodology and ploidy event. In this study, in vitro embryo culture was employed to recover natural hybrids from monoembryonic diploid, open-pollinated mandarin. Flow cytometry was used to determine ploidy level. A total of 10,289 seeds were extracted from 792 fruits having approximately 13 seeds per fruit. Average frequency of small seeds developed was 7.1%, while the average frequency of small seeds per fruit were: 8.9% for 'Clementine' 10.2% for 'Harehime' 2.6% for 'Kamja' 3.1% for 'Pyunkyool' 2.8% for 'Sadookam' and 7.0% for 'Wilking' mandarin. Average size of a perfect seed was $49.52{\pm}0.07mm^2$ ('Clementine') while the small seed measured $7.95{\pm}0.04mm^2$ ('Clementine'), which was about 1/6 smaller than the perfect seed. In total, 731 small seeds were obtained and all of them contained only one embryo per seed. The efficiency of 'Clementine' was 14 times higher than 'Wilking' and more than 109 times higher than 'Pyunkyool'. The basic information on spontaneous polyploidy provides for the hybridization of constant triploids and increases the efficiency of conventional cross.

Performance Analysis of a Deep Vertical Closed-Loop Heat Exchanger through Thermal Response Test and Thermal Resistance Analysis (열응답 실험 및 열저항 해석을 통한 장심도 수직밀폐형 지중열교환기의 성능 분석)

  • Shim, Byoung Ohan;Park, Chan-Hee;Cho, Heuy-Nam;Lee, Byeong-Dae;Nam, Yujin
    • Economic and Environmental Geology
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    • v.49 no.6
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    • pp.459-467
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    • 2016
  • Due to the limited areal space for installation, borehole heat exchangers (BHEs) at depths deeper than 300 m are considered for geothermal heating and cooling in the urban area. The deep vertical closed-loop BHEs are unconventional due to the depth and the range of the typical installation depth is between 100 and 200 m in Korea. The BHE in the study consists of 50A (outer diameter 50 mm, SDR 11) PE U-tube pipe in a 150 mm diameter borehole with the depth of 300 m. In order to compensate the buoyancy caused by the low density of PE pipe ($0.94{\sim}0.96g/cm^3$) in the borehole filled with ground water, 10 weight band sets (4.6 kg/set) were attached to the bottom of U-tube. A thermal response test (TRT) and fundamental basic surveys on the thermophysical characteristics of the ground were conducted. Ground temperature measures around $15^{\circ}C$ from the surface to 100 m, and the geothermal gradient represents $1.9^{\circ}C/100m$ below 100 m. The TRT was conducted for 48 hours with 17.5 kW heat injection, 28.65 l/min at a circulation fluid flow rate indicates an average temperature difference $8.9^{\circ}C$ between inlet and outlet circulation fluid. The estimated thermophysical parameters are 3.0 W/mk of ground thermal conductivity and 0.104 mk/W of borehole thermal resistance. In the stepwise evaluation of TRT, the ground thermal conductivity was calculated at the standard deviation of 0.16 after the initial 13 hours. The sensitivity analysis on the borehole thermal resistance was also conducted with respect to the PE pipe diameter and the thermal conductivity of backfill material. The borehole thermal resistivity slightly decreased with the increase of the two parameters.

Relationship between Gb3 Expression and Cytotoxicity of Shiga-like Toxin I (Shiga-like Toxin I의 세포독성과 수용체 Gb3 발현과의 관계)

  • Lim, Suk-Hwan;Kim, Gi-Young;Kim, Hyung-Chun;Kim, Young-Hee;Son, Yong-Hae;Oh, Yang-Hyo;Park, Yeong-Min
    • Clinical and Experimental Pediatrics
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    • v.46 no.2
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    • pp.143-153
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    • 2003
  • Purpose : Infection with Shiga-like toxin (SLT)-producing Escherichia coli, an emerging human pathogen found particularly in young children under 5 years of age, causes a spectrum of illnesses with high morbidity and mortality, ranging from diarrhea to hemorrhagic colitis and hemolytic uremic syndrome. Host mediators play an important role in the pathogenesis of SLT-I toxicity. The experiments described here were designed to investigate the effect of SLT-I on TNF-${\alpha}$ production and to understand the effect of TNF-${\alpha}$ on GB3 expression. We also further examine the relationship between the Gb3 level and the differential susceptibility of cells to the cytotoxic action of SLT-I. Methods : The effect of purified SLT-1 from E. coli O157 : H7 (ATCC 43890) on tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) production in Raw264.7 cells was investigated. Many mediators regulate endothelial cell membrane expression of the glycolipid globotriaosyleramide (Gb3), which serves as the toxin receptor, suggesting that the host response to the toxin or other bacterial products may contribute to pathogenesis by regulating target cell sensitivity to the toxins. Therefore, the relationships between Gb3 expression and cytotoxicity against SLT-I on three types of cells were evaluated. Results : Detectable levels of TNF-${\alpha}$ were produced as early as six hours after induction and continued to increase during 48 hours by SLT-I. It was also found that Vero cells and dendritic cells (DC2.4 cells) expressed high levels of Gb3, 83% and 68%, respectively, and that Raw264.7 cells had a low level of Gb3 (29%) and appeared refractory to cytotoxicity against SLT-I. Vero cells and DC2.4 cells expressing high levels of Gb3 were highly susceptible to SLT-I. Furthermore, macrophages showed a resistance to SLT-I cytotoxicity, despite the fact that Gb3 expression was enhanced. Conclusion : These results strongly suggest that the expression of Gb3 is necessary but not sufficient to confer sensitivity of macrophages to SLT-I and further underpin the important role of SLT-I and its Gb3 receptors in the pathogenesis of E. coli O157 infection.