• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.666-671
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• 2012

Gas hydrates are inclusion compounds formed when small-sized guest molecules are incorporated into the well defined cages made up of hydrogen bonded water molecules. Since large masses of natural gas hydrates exist in permafrost regions or beneath deep oceans, these naturally occurring gas hydrates in the earth containing mostly $CH_4$ are regarded as future energy resources. The heat of dissociation is one of the most important thermal properties in exploiting natural gas hydrates. The accurate and direct method to measure the dissociation enthalpies of gas hydrates is to use a calorimeter. In this study, the high pressure micro DSC (Differential Scanning Calorimeter) was used to measure the dissociation enthalpies of methane, ethane, and propane hydrates. The accuracy and repeatability of the data obtained from the DSC was confirmed by measuring the dissociation enthalpy of ice. The dissociation enthalpies of methane, ethane, and propane hydrates were found to be 54.2, 73.8, and 127.7 kJ/mol-gas, respectively. For each gas hydrate, at given pressures the dissociation temperatures which were obtained in the process of enthalpy measurement were compared with three-phase (hydrate (H) - liquid water (Lw) - vapor (V)) equilibrium data in the literature and found to be in good agreement with literature values.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.205-208
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• 2005

최근 열선 화학 기상 증착법(HWCVD)은 낮은 온도에서 TFT용 Poly Si 중착을 할 수 있다는 점과 실리콘 박막을 빠른 속도로 증착할 수 있다는 점에서 각광을 받고 있다. 본 연구에서는 HWCVD를 이용하여 태양전지를 제조하고 그 특성을 평가하였다. 조건에 따른 실리콘 박막의 특성 변화를 알기 위해 corning glass 및 실리콘 wafer에 다양한 조건에서 단위 박막(intrinsic layer)을 증착하였고 이 결과를 바탕으로 p/i/n 구조의 태양전지를 제조하였다. Ta 열선 온도는 1700-2000도였고 가스 원료인 $SiH_4$와 수소의 비율을 조절하면서 그 영향을 관찰하였다. 태양전지의 경우 p충과 n충은 PECVD로 증착하였으며 단위박막 및 태양전지 i충 증착시 기판과 열선간의 거리는 7cm, 기판 온도는 $200^{\circ}C$와 $250^{\circ}C$로 고정하였고 작업압력은 30mTorr였다. 단위 박막 특성 평가를 위해 암/광 전도도, SEM, Raman Scattering, FT-IR등을 사용하였으며 태양전지 특성 평가를 위해 I-V 및 Spectral response를 측정하였다. 열선 온도가 증가함에 따라 증착속도 및 결정화 분율은 증가하였다. 특히 비정질에서 결정질로 전이되는 구간은 매우 좁았으며 여러 분석 방법에서 일치되는 결과를 보였다. $SiH_4$ 유량이 늘어날수록 비정질이 결정질로 바뀌는 열선 온도가 증가하였으며 기판 온도가 낮을 경우 또한 결정으로 바뀌는 열선 온도가 증가하였다. 태양전지의 경우 열선 온도가 증가함에 따라 $V_{oc}$ 및 W가 낮아졌으며 $J_{sc}$, 는 증가하는 경향을 보였으며 결정질 비율이 증가하는 것을 관찰할 수 있었다. 이러한 경향은 quantum efficiency 결과에서도 확인할 수 있었다.용을 반복하면서 석재 내부와 외부의 암석 및 결정에 균열과 미세열극 등이 생성되어 석재 자체의 구조적 안정성에 영향을 주고 있다. 따라서 감은사지 석탑은 지리적 환경 차이로 인해 일반적인 환경의 석조물들과는 다른 형태의 풍화양상을 보이고 있어서 풍화양상 및 풍화형태에 대한 정확한 연구와 이해를 바탕으로 보존대책이 마련되어야 한다.되었다. 이런 모든 시편들을 각 탈염방법에 따라 탈염처리한 후 XRD와 SEM-EDS으로 분석한 결과 인철광과 침철광은 어떠한 변화도 보이지 않았고, 다만 적금광으로 동정된 시편만이 잔존하지 않았다. 철기 제작별 $Cl^-$ 이온 추출량과 탈염효과에 대한 비교 실험은 이온 크로마토그래피 분석 결과와 마찬가지로 단조 철제유물이 주조 철제보다 $Cl^-$ 이온을 많이 가지고 있었으며, 탈염 처리 후에는 $Cl^-$ 이온은 전혀 발견되지 않았다. 이상의 결과 $K_2CO_3$와 Sodium 용액은 탈염처리에서 가장 적합한 탈염처리 용액으로 알수가 있었으며 특히 어떠한 탈염 용액으로 유물을 처리한다 해도 철제유물에 생성된 부식물은 제거되지 않는다는 것을 알게 되었다. 따라서 보존처리자는 유물 표면의 부식 상태만을 보고 처리하기 보다는 철기제작물로 고려하여 처리하는 것이 필요하다. 또한 금속에 부식을 야기시키는 $Cl^-$ 이온과 부식물을 완전하게 제거하여 탈염처리를 하는 것이 유물 부식을 최대한 지연시킬 수 있는 것이라 생각된다.TEX>$88\%$)였다.(P=0.063). 결론: 본 연구에서는 MTHFR C/T & T/T 유전자 다형성이 위암의 발생과 그 위치에 대해 관련이 있는 것으로 여겨지고, 흡연력, 음주력과는 관련이 없는 것으로 여겨진다.험이 커지는 경향을 보였으나, 나이 및 병기, 종양의 크기, MD-BED $Gy_{10}$ 등의 예후 인자를 보정한 다변

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.519-526
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• 1992

The gene coding for urease of alkalophilic Bacillus pasteurii had been cloned in Escherichia coli previously. The urease protein was purified 63.1-fold by TEAE-cellulose, DEAE-Sephadex A-50, Sephadex G-150 and Sephadex G-200 chromatographies with a 7.3% yield from the sonicated fluid of the E. coli HB1Ol(pBUll) encoding B. pasteurii urease gene. The ureases of E. coli (pBUll) and B. pasteurii possessed as a $K_m$ for urea, 42.1 mM and 40.4 mM, respectively. They hydrolyzed urea with $V_{max}$ of 86.9$\mu$mol/min and 160$\mu$mol/min, respectively. Both ureases were composed with four subunits (Mrs 67,000) and a subunit (Mr 20,000). The molecular weight of both native enzymes was Mr 280,OOO$pm$10,000 determined by gel filtration chromatography and Coomassie blue staining of the subunits. The optimal reaction pH of both ureases were pH 7.5. The ureases were stabled in pH 5.5-10.5. The optimal reaction temperature of both ureases were $60^{\circ}C$, and the ureases were stable for an hour at $50^{\circ}C$, 40min at $60^{\circ}C$ and 10 min at $70^{\circ}C$ The activity of both enzymes were inhibited completely by $Ag^{2+}$, $Hg^{2+}$, $Zn^{2+}$, $Cu^{2+}$, and were inhibited 60% by CoH, 30% by $Fe^{2+}$ and 10% by $Pb^{2+}$. However it was increased by the addition of $Sn^{2+}$, $Mn^{2+}$, $Mg^{2+}$ at concentration of $1{\times}10^{-3}$M. Both ureases were inhibited completely by p-CMB and acetohydroxamic acid. The urease expressed in E. coli (pBU11) was inhibited 70% by SDS. The urease of B. pasteurii was inhibited 40% by hydroxyurea, whereas the recombinant urease of E. coli strain was inhibited 17%. Both enzymes were not inhibited by cyclohexanediaminetetraacetic acid (CDTA) and ethylendiaminetetraacetic acid (EDTA).

• Korean Journal of Weed Science
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• v.14 no.3
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• pp.212-222
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• 1994

Thiobencarb retarded the growth of new leaves in only barnyardgrass under dry condition while under water condition the shoot growth of broadcast rice, and both shoot and root growth of barnyardgrass was considerably inhibited. Root elongation of rice and barnyardgrass was severely inhibited only under water condition, while that of transplanted rice was slightly inhibited. Inhibition of shoot and root growth in broadcast, drilled rice and barnyardgrass under water condition was much higher than that under dry condition, whereas the inhibition was less in transplanted rice than direct seeded rice. Microscopically, thiobencarb severely inhibited shoot growth and development of barnyardgrass by inducing tubular-like leaves. The cells of the shoot apices of treated barnyardgrass seedling under dry condition was vacuolated and irregularly arranged. Under water condition, leaf primordia of broadcast rice was constricted, barnyardgrass showed tubular-like leaves, inhibited apices elongation and vacuolated cells(visually lack cytoplasm).

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.1
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• pp.48-59
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• 2023

Ground-level ozone affects human health and plant growth. Ozone is produced by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs) from anthropogenic and biogenic sources. In this study, two different land cover and emission factor datasets were input to the MEGAN v2.1 emission model to examine how these parameters contribute to the biogenic emissions and ozone production. Four input sensitivity scenarios (A, B, C and D) were generated from land cover and vegetation emission factors combination. The effects of BVOCs emissions by scenario were also investigated. From air quality modeling result using CAMx, maximum 1 hour ozone concentrations were estimated 62 ppb, 60 ppb, 68 ppb, 65 ppb, 55 ppb for scenarios A, B, C, D and E, respectively. For maximum 8 hour ozone concentration, 57 ppb, 56 ppb, 63 ppb, 60 ppb, and 53 ppb were estimated by scenario. The minimum difference by land cover was up to 25 ppb and by emission factor that was up to 35 ppb. From the modeling performance evaluation using ground ozone measurement over the six regions (East Seoul, West Seoul, Incheon, Namyangju, Wonju, and Daegu), the model performed well in terms of the correlation coefficient (0.6 to 0.82). For the 4 urban regions (East Seoul, West Seoul, Incheon, and Namyangju), ozone simulations were not quite sensitive to the change of BVOC emissions. For rural regions (Wonju and Daegu) , however, BVOC emission affected ozone concentration much more than previously mentioned regions, especially in case of scenario C. This implies the importance of biogenic emissions on ozone production over the sub-urban to rural regions.

• 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.

• Cartoon and Animation Studies
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• s.27
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• pp.1-30
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• 2012

Oshii Mamoru attempts to project the perception of reality about his own modern world as it is through animation. The precedent studies on Oshii Mamoru put their focus on the point that his works have a tendency to represent the devastation of reality as the image of 'a ruin.' In addition, they gave an impression that Oshii Mamoru's animation has gradually developed to expose the 'realistic taste[beauty]' from the design perspective. However, this study is going to put its focus on the point that Mamoru's works were created as an attempt at finding the subversive possibility of the suppressed modern world under the modern capitalism in the aspect of 'everyday life' of the modern world. First, for its analytical purpose, this study intends to do that by dividing the work into the three layers such as space, body and everyday life. In Chapter II, this study, in relation with the issue of 'space' representation, analyzed the space in into the modern, mechanical, compactly capitalized space and also the space just like a closed circuit having the nature of 'repetition.' In Chapter III, this analyzed that suggests the body moving freely between a human named 'Kildren' and the inhuman from the aspect of character's body, through which Mamoru represents the capitalized, reified body of the modern world. In addition, this analyzed the extreme anxiety facing the body into the reflection of the phenomena of 'anxiety' and 'placelessness' consequent on the labor flexibility of the modern world. In Chapter IV, this study, on the basis of the analysis of layers of space & body, analyzed that the 'everyday life' of the modern world was represented in the respects of 'memory' and 'habit', and in the aspects of Mise-en-Sc$\grave{e}$ne, design and direction. In Chapter V, this rooted out the fact that Mamoru suggested the attempt at 'appropriation' based on his perception of reality about such a modern world. Such a finding includes unearthing the fact that Oshii Mamoru's work is raising a question about how to desert and appropriate the modern space. In conclusion of Chapter VI, this drew the conclusion that Oshii Mamoru's work represented the layer of 'everyday life' while dealing with the post-modern themes shown by the existing modern SF genre, provided the 'window' through which people can perceive the 'modern world radically by recommending an attempt at 'appropriation', and blazed a trail in a new realm of creation for animations.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.3
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• pp.379-389
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• 2008

This study was conducted to assess the microbiological quality of raw and cooked foods served in the elementary school food service. Raw and cooked food samples were collected from 11 selected elementary schools in both June to July and September to October of 2005. Petrifilm plates were used to determine (in duplicate) total aerobic colony counts (PAC), Enterobacteriaceae (PE), coliform counts (PCC), and E. coli counts (PEC). Heavy contamination of Enterobacteriaceae (from 0.08 to 7.40 log CFU/g) and total coliform (0.50 to 6.52 log CFU/g) were observed in raw materials and cooked foods. Escherichia coli (E. coli) were detected in the sample of currant tomato (3.70 log CFU/g), sesame leaf (3.59 log CFU/g), dropwort (0.20 log CFU/g), crown daisy (3.15 log CFU/g), parsley (3.00 log CFU/g), peeled green onion (1.74 log CFU/g), frozen pork (0.65 log CFU/g), frozen beef (0.20 or 1.50 log CFU/g), chicken (1.78 log CFU/g), and young radish leaf seasoned with soybean paste (1.24 log CFU/g). Multiplex PCR system was used to determine the food-borne pathogens: Salmonella spp., Bacillus cereus (B. cereus), E. coli O157:H7, Staphylococcus aureus, Listeria monocytogenes (L. monocytogenes), Vibrio parahaemolyticus, Campylobacter jejuni (C. jejuni), Shigella spp., B. cereus was detected in 19 samples of raw materials and 8 samples of cooked foods. With regard to quantitative analysis, B. cereus counts exceeded 5.46, 3.48 and 1.79 log CFU/g in sesame leaf, peeled green onion and seasoned mungbean jelly, respectively. E. coli O157:H7 was detected on 2 samples of frozen beefs, and its biochemical characteristics of one beef sample was confirmed with API 20E kit (93.7%). L. monocytogenes was detected in fried rice paper dumpling, but the presumptive colonies were not detected onto the conventional plate. C. jejuni was detected in peeled & washed onion.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.1
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• pp.23-30
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• 2007

The ultimate objective of this study is to develop oxygen-enriched combustion techniques applicable to the system of practical industrial boiler. To this end the combustion characteristics of lab-scale LNG combustor were investigated as a first step using the method of numerical simulation by analyzing the flame characteristics and pollutant emission behaviour as a function of oxygen enrichment level. Several useful conclusions could be drawn based on this study. First of all, the increase of oxygen enrichment level instead of air caused long and thin flame called laminar flame feature. This was in good agreement with experimental results appeared in open literature and explained by the effect of the decrease of turbulent mixing due to the decrease of absolute amount of oxidizer flow rate by the absence of the nitrogen species. Further, as expected, oxygen enrichment increased the flame temperatures to a significant level together with concentrations of $CO_2$ and $H_2O$ species because of the elimination of the heat sink and dilution effects by the presence of $N_2$ inert gas. However, the increased flame temperature with $O_2$ enriched air showed the high possibility of the generation of thermal $NO_x$ if nitrogen species were present. In order to remedy the problem caused by the oxygen-enriched combustion, the appropriate amount of recirculation $CO_2$ gas was desirable to enhance the turbulent mixing and thereby flame stability and further optimum determination of operational conditions were necessary. For example, the adjustment of burner with swirl angle of $30\sim45^{\circ}$ increased the combustion efficiency of LNG fuel and simultaneously dropped the $NO_x$ formation.

• Magazine of the Korean Society of Agricultural Engineers
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• v.16 no.1
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• pp.3225-3262
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• 1974

The purposes of this thesis are to clarify experimentally the variation of ground water temperature in tube wells during the irrigation period of paddy rice, and the effect of ground water irrigation on the growth, grain yield and yield components of the rice plant, and, furthermore, when and why the plant is most liable to be damaged by ground water, and also to find out the effective ground water irrigation methods. The results obtained in this experiment are as follows; 1. The temperature of ground water in tube wells varies according to the location, year, and the depth of the well. The average temperatures of ground water in a tubewells, 6.3m, 8.0m deep are $14.5^{\circ}C$ and $13.1^{\circ}C$, respercively, during the irrigation period of paddy rice (From the middle of June to the end of September). In the former the temperature rises continuously from $12.3^{\circ}C$ to 16.4$^{\circ}C$ and in the latter from $12.4^{\circ}C$ to $13.8^{\circ}C$ during the same period. These temperatures are approximately the same value as the estimated temperatures. The temperature difference between the ground water and the surface water is approximately $11^{\circ}C$. 2. The results obtained from the analysis of the water quality of the "Seoho" reservoir and that of water from the tube well show that the pH values of the ground water and the surface water are 6.35 and 6.00, respectively, and inorganic components such as N, PO4, Na, Cl, SiO2 and Ca are contained more in the ground water than in the surface water while K, SO4, Fe and Mg are contained less in the ground water. 3. The response of growth, yield and yield components of paddy rice to ground water irrigation are as follows; (l) Using ground water irrigation during the watered rice nursery period(seeding date: 30 April, 1970), the chracteristics of a young rice plant, such as plant height, number of leaves, and number of tillers are inferior to those of young rice plants irrigated with surface water during the same period. (2) In cases where ground water and surface water are supplied separately by the gravity flow method, it is found that ground water irrigation to the rice plant delays the stage at which there is a maximum increase in the number of tillers by 6 days. (3) At the tillering stage of rice plant just after transplanting, the effect of ground water irrigation on the increase in the number of tillers is better, compared with the method of supplying surface water throughout the whole irrigation period. Conversely, the number of tillers is decreased by ground water irrigation at the reproductive stage. Plant height is extremely restrained by ground water irrigation. (4) Heading date is clearly delayed by the ground water irrigation when it is practised during the growth stages or at the reproductive stage only. (5) The heading date of rice plants is slightly delayed by irrigation with the gravity flow method as compared with the standing water method. (6) The response of yield and of yield components of rice to ground water irrigation are as follows: \circled1 When ground water irrigation is practised during the growth stages and the reproductive stage, the culm length of the rice plant is reduced by 11 percent and 8 percent, respectively, when compared with the surface water irrigation used throughout all the growth stages. \circled2 Panicle length is found to be the longest on the test plot in which ground water irrigation is practised at the tillering stage. A similar tendency as that seen in the culm length is observed on other test plots. \circled3 The number of panicles is found to be the least on the plot in which ground water irrigation is practised by the gravity flow method throughout all the growth stages of the rice plant. No significant difference is found between the other plots. \circled4 The number of spikelets per panicle at the various stages of rice growth at which_ surface or ground water is supplied by gravity flow method are as follows; surface water at all growth stages‥‥‥‥‥ 98.5. Ground water at all growth stages‥‥‥‥‥‥62.2 Ground water at the tillering stage‥‥‥‥‥ 82.6. Ground water at the reproductive stage ‥‥‥‥‥ 74.1. \circled5 Ripening percentage is about 70 percent on the test plot in which ground water irrigation is practised during all the growth stages and at the tillering stage only. However, when ground water irrigation is practised, at the reproductive stage, the ripening percentage is reduced to 50 percent. This means that 20 percent reduction in the ripening percentage by using ground water irrigation at the reproductive stage. \circled6 The weight of 1,000 kernels is found to show a similar tendency as in the case of ripening percentage i. e. the ground water irrigation during all the growth stages and at the reproductive stage results in a decreased weight of the 1,000 kernels. \circled7 The yield of brown rice from the various treatments are as follows; Gravity flow; Surface water at all growth stages‥‥‥‥‥‥514kg/10a. Ground water at all growth stages‥‥‥‥‥‥428kg/10a. Ground water at the reproductive stage‥‥‥‥‥‥430kg/10a. Standing water; Surface water at all growh stages‥‥‥‥‥‥556kg/10a. Ground water at all growth stages‥‥‥‥‥‥441kg/10a. Ground water at the reproductive stage‥‥‥‥‥‥450kg/10a. The above figures show that ground water irrigation by the gravity flow and by the standing water method during all the growth stages resulted in an 18 percent and a 21 percent decrease in the yield of brown rice, respectively, when compared with surface water irrigation. Also ground water irrigation by gravity flow and by standing water resulted in respective decreases in yield of 16 percent and 19 percent, compared with the surface irrigation method. 4. Results obtained from the experiments on the improvement of ground water irrigation efficiency to paddy rice are as follows; (1) When the standing water irrigation with surface water is practised, the daily average water temperature in a paddy field is 25.2$^{\circ}C$, but, when the gravity flow method is practised with the same irrigation water, the daily average water temperature is 24.5$^{\circ}C$. This means that the former is 0.7$^{\circ}C$ higher than the latter. On the other hand, when ground water is used, the daily water temperatures in a paddy field are respectively 21.$0^{\circ}C$ and 19.3$^{\circ}C$ by practising standing water and the gravity flow method. It can be seen that the former is approximately 1.$0^{\circ}C$ higher than the latter. (2) When the non-water-logged cultivation is practised, the yield of brown rice is 516.3kg/10a, while the yield of brown rice from ground water irrigation plot throughout the whole irrigation period and surface water irrigation plot are 446.3kg/10a and 556.4kg/10a, respectivelely. This means that there is no significant difference in yields between surface water irrigation practice and non-water-logged cultivation, and also means that non-water-logged cultivation results in a 12.6 percent increase in yield compared with the yield from the ground water irrigation plot. (3) The black and white coloring on the inside surface of the water warming ponds has no substantial effect on the temperature of the water. The average daily water temperatures of the various water warming ponds, having different depths, are expressed as Y=aX+b, while the daily average water temperatures at various depths in a water warming pond are expressed as Y=a(b)x (where Y: the daily average water temperature, a,b: constants depending on the type of water warming pond, X; water depth). As the depth of water warning pond is increased, the diurnal difference of the highest and the lowest water temperature is decreased, and also, the time at which the highest water temperature occurs, is delayed. (4) The degree of warming by using a polyethylene tube, 100m in length and 10cm in diameter, is 4~9$^{\circ}C$. Heat exchange rate of a polyethylene tube is 1.5 times higher than that or a water warming channel. The following equation expresses the water warming mechanism of a polyethylene tube where distance from the tube inlet, time in day and several climatic factors are given: {{{{ theta omega (dwt)= { a}_{0 } (1-e- { x} over { PHI v })+ { 2} atop { SUM from { { n}=1} { { a}_{n } } over { SQRT { 1+ {( n omega PHI) }^{2 } } } } LEFT { sin(n omega t+ { b}_{n }+ { tan}^{-1 }n omega PHI )-e- { x} over { PHI v }sin(n omega LEFT ( t- { x} over {v } RIGHT ) + { b}_{n }+ { tan}^{-1 }n omega PHI ) RIGHT } +e- { x} over { PHI v } theta i}}}}{{{{ { theta }_{$\infty$ }(t)= { { alpha theta }_{a }+ { theta }_{ w'} +(S- { B}_{s } ) { U}_{w } } over { beta } , PHI = { { cpDU}_{ omega } } over {4 beta } }}}} where $\theta$$\omega$; discharged water temperature($^{\circ}C$) $\theta$a; air temperature ($^{\circ}C$) $\theta$$\omega$';ponded water temperature($^{\circ}C$) s ; net solar radiation(ly/min) t ; time(tadian) x; tube length(cm) D; diameter(cm) ao,an,bn;constants determined from $\theta$$\omega$(t) varitation. cp; heat capacity of water(cal/$^{\circ}C$ ㎥) U,Ua; overall heat transfer coefficient(cal/$^{\circ}C$ $\textrm{cm}^2$ min-1) $\omega$;1 velocity of water in a polyethylene tube(cm/min) Bs ; heat exchange rate between water and soil(ly/min)