• Korean Journal of Environmental Agriculture
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• v.17 no.2
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• pp.117-121
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• 1998

In the study to reduce the error on the method of sampling pine needles to monitor the atmospheric concentration of polychlorinated biphenyls(PBCs),it was found that: 1. Concentration of PCBs almost linearly increased from new to three-years-old pine needles, so that the biomonitoring method using pine needles canbe applied to measuring long-term contamination from air in a local area. Needles of differernt age should not be mixed in sampling but be seperately analysed .It no good idea comparing PCB concentrations of differently aged needles. 2. Concentratio n of PCBs on pine needles had nothing to do whit the indivisual and age of the pine tree. 3. Concentration of PCBs on pine needles growing avobe was lower than that on needke below. 4. Concentration of PCBs on pine needles locatied in poorly ventilative places such as needle of a forest was lower than that on needles in well-ventilated areas.

• Korean Journal of Environmental Agriculture
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• v.29 no.4
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• pp.388-395
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• 2010

In order to decrease level of an organophosphorus fungicide, tolclofos-methyl, from in situ ginseng cultivating soil, we isolated a tolclofos-methyl degrading bacteria from ginseng cultivating soil samples. The bacterial strain removed tolclofos-methyl around 95% after 3 days incubation with complete liquid media. The strain was identified as Sphingomonas sp. by 16S rDNA sequence comparison, and designated as Sphingomonas sp. 224. Through the GC-MS analysis, Sphingomonas sp. 224 was proposed to have an initiative degradation pathway generating the metabolite such as 2,6-dichloro-4-methyl phenol compound from tolclofos-methyl. In addition, Sphingomonas sp. 224 was confirmed representing the effective degrading capability to tolclofosmethyl in situ soil.

• Korean Journal of Environmental Biology
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• v.19 no.1
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• pp.19-24
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• 2001

Agricultural pesticides may cause certain biological risks since they are widely used to eradicate pests. Agricultural disasters may arise even from the possibility of their synergistic interaction with other harmful enviromnetal factors. The effect of pesticide on radiation-induced DNA damage in human blood lymphocytes was evaluated by the single cell gel electrophoresis (SCGE) assay. The lymphocytes, with or without pretreatment of the pesticide, were exposed to 0-2.0 Gy of $^60 CO$ gamma ray. Significantly increased tail moment, which was a marker of DNA strand breaks in SCGE assay, showed an excellent dose-response relationship. The present study confirms that the pesticide has the cytotoxic effect on lymphocytes and that it shows the synergistic interaction with radiation on DNA damage as well. The results may have a role of providing biological information necessary for the prevention of environmental disaster.

• Journal of Embryo Transfer
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• v.21 no.1
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• pp.29-34
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• 2006

본 연구는 개 체외성숙 난자를 안정적으로 생산하기 위하여 채취시기, 난구세포 부착 여부 및 배양액에 EGF와 호르몬을 첨가 후 배양했을 때 체외성숙율에 미치는 영향을 조사하였다. 1. 미성숙 난포란을 TCM-199 배양액에서 24, 45시간 배양했을 때 체외성숙율은 각각 7.93%, 8.94%로서 48시간 배양했을 때 가장 높은 체외성숙율을 나타냈다. 2. 휴지기, 난포기, 황체기에 채취한 난소로부터 회수한 난자를 20 ng/ml의 EGF가 첨가된 TCM-199 배양액에서 배양했을 때 체외성숙율은 14.3%로서 0, 10 ng/ml의 EGF 첨가군(3.1%, 7.5%)에 비해 높은 체외성숙율을 나타냈다. 3. 난구세포 부착 및 미부착 난자를 48시간 배양했을 때 체외성숙율은 각각 18.8% 및 7.5%로서 난구세포 부착 난자가 미부착 난자보다 높은 체외성숙율을 나타냈다. 4. 난자의 체외성숙 배양 시 0.5 mg/ml FSH, 5 mg/ml LH, 1 mg/ml $E_2$와 FSH+LH, $FSH+LH+E_2$를 첨가한 TCM-199 배양액에서 배양했을 때 체외성숙율은 각각 1.2%, 10.0%, 2.0%와 10.0%, 31.2%로서 호르몬의 병용처리군이 높은 체외성숙율을 나타냈다. 5. 난자의 체외성숙 배양 시 EGF와 FSH, LH, $E_2$ 및 EGF와 FSH+LH, $FSH+LH+E_2$를 첨가한 TCM-199 배양액에서 배양했을 때 체외성숙율은 32.3%, 27.0%, 3.0%와 36.2%, 69.4%로서 EGF와 호르몬 병용 처리군이 높은 체외성숙율을 나타냈다.

• School Mathematics
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• v.10 no.3
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• pp.375-399
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• 2008

Infinitesimal did not play an explicit role concerning definite integral in the textbook nowadays. But studies which investigate understanding of students on definite integral show that many students comprehend definite integral with infinitesimal. Formally infinitesimal is not taught at mathematics classroom, but many students identify definite integral as infinite sum of infinitesimals. This means that definite integral itself contains some structural elements that allow infinitesimal interpretation. In this study we investigate the role of infinitesimal In the historical development of partition-sum in definite integral, extract didactical issues concerning understanding of definite integral, and analyse Korean mathematics textbooks. Finally we propose some suggestions on the teaching of definite integral which contains the process of refinement intuition.

• Journal of Embryo Transfer
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• v.21 no.1
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• pp.77-83
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• 2006

본 연구는 개 동결 정액 융해 시 straw 크기 및 융해 속도가 융해 정자의 질(quality)에 미치는 영향을 조사하고 최적의 융해 조건을 조사하는데 그 목적이 있다. 정상적인 번식능을 가진 비글 수컷 5마리에서 정액을 채취하여 원심 분리하여 정장을 버리고 남은 정자에 동결보호제인 glycerol이 첨가된 tris-glucose-egg yolk extender를 첨가하여 동결하고 액체질소에 보관한 후 융해하였다. 동결 융해 조건에 따른 효과를 알아보기 위해 straw는 0.25 ml과 0.5 ml크기를 사용하였고 융해 조건은 $75^{\circ}C$에 10초, $55^{\circ}C$에 12초 및 $37^{\circ}C$에서 120초로 하여 융해 후 정자의 활력도(vigor), 운동성(motility), Hypo-osmotic test(HOS test)를 이용한 생존성(viability) 및 $SperMac^{\circledR}$ 염색을 하여 정자의 membrane integrity를 비교 조사하였다. 조사 결과 0.5 ml 크기의 straw를 사용한 경우 $37^{\circ}C$ 융해가 $55^{\circ}C,\;75^{\circ}C$ 융해보다, 0.25 ml 크기의 straw를 사용한 경우에는 $37^{\circ}C,\;55^{\circ}C$ 융해가 $75^{\circ}C$ 융해보다 유의적으로 높은 활력 지수 및 생존성을 보였다(P<0.05). Straw크기에 따라 비교하였을 경우 0.5 ml 군에서 유의적으로 높은 활력도, 생존성 및 membrane integrity를 보였다(P<0.05). 결론적으로 개 정액이 동결 및 융해 시 0.5ml straw를 이용하여 동결한 후 $37^{\circ}C$에서 120초 동안 융해하는 것이 최적의 조건임이 사료된다.

• Journal of fish pathology
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• v.17 no.2
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• pp.91-98
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• 2004

This study was performed for the identification of Streptococcus sp. from cultured flounders (Paralichthys olivaceus) showing streptococcosis in the Jeju island. We isolated 10 strains of Streptococcus iniae from the cultured olive flounders with streptococcosis. Isolated strains were identified in S. iniae since they have formed the expected band through performing PCR assay using specific primers, Sin-1 (5'-CTAGAGTACACATGTACT(AGCT)AAG-3') and Sin-2 (5'-GGATTTTCCACTCCCATTAC-3'). In addition to 16S-23S rRNA intergenic spacers (ISR), operon structure of isolated strains showed that all strains had three 16S-23S rRNA ISR band patterns. The 16S-23S rRNA ISR sequence of isolated strains showed 96% sequence identity with S. iniae (GenBank accession number AF 048773). This paper is the first report that S. iniae is associated with streptococcosis of Olive flounder in Korea.

• Journal of Internet Computing and Services
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• v.8 no.2
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• pp.77-87
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• 2007

A typical VOD service allows that a number of remote clients playback a desired video from a large collection of videos stored in one or more video servers. The main bottleneck for a VOD service is the network bandwidth connecting to the VOD server to the client due to the high bandwidth requirements. Many previous researches have shown that VOD server can be greatly improved through the use of multicast, broadcast, or P2P scheme. Broadcast is one of the most efficient techniques because it can transmit a stream to many users without additional network bandwidth. But the broadcast has long latency time. In order to overcome the drawback, in this paper, we propose P2Prefix broadcast scheme that can solve the service latency time, which is the problem of broadcast scheme, by using P2P caching as well as minimizing the client buffer requirement.

• Journal of Internet Computing and Services
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• v.9 no.4
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• pp.97-114
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• 2008

Eclipse is an open integrated environment for software development, rapidly emerging as the de facto standard for developing java applications. Also, it is easily extensible since new functions for the environment can be added through the installation of various plug-in modules. WebDAV is an IETF standard protocol, which is an extended version of HTTP 1.1, supporting asynchronous collaborative authoring of various contents on the web. In this paper, we describe the development of the DAVSpace plug-in which enables programmers to use remote workspaces offered by WebDAV servers as project workspaces for software development in Eclipse. Based on the WebDAV protocol, DAVSpace supports the management of resources on the remote workspaces associated with projects in Eclipse. Using DAVSpace, we can create a project in Eclipse on a designated remote workspace in addition to the default local workspace. Whenever an event for storing a resource is generated, DAVSpace stores the resource into both workspaces. Thanks to DAVSpace, developers can effectively proceed their projects regardless of where they are located.

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.1029-1033
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• 1997

Fundamental research of non-isothermic analysis of reaction rate has been carried out for the heat storage system using the thermal decomposition of $Na_2B_4O_7{\cdot}10H_2O$. It was found that the equilibrium temperature of the thermal decomposition reaction was lowered less than 373K in $Na_2B_4O_7{\cdot}10H_2O/Na_2B_4O_7{\cdot}5H_2O$ system, but the heat efficiency was unchanged. The initiation temperature of the reaction was varied from low to high temperature region with heating rate. The reaction order of the dehydration reaction by the thermal decomposition was appeared to be 0.67 by non-isothermic analysis, thereby $Na_2B_4O_7{\cdot}10H_2O$ may be used as a hemical heatstorage material.