• Applied Microscopy
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• v.32 no.2
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• pp.91-105
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• 2002

Urea transport in the kidney is mediated by a family of transporter proteins that includes renal urea transporters (UT-A) and erythrocyte urea transporters (UT-B). The cDNA of five isoforms of rat UT-A, UTA1, UT-A2, UT-A3, UT-A4, and UT-A5 have been cloned. The purpose of this study was to examine the expression of UT-A (L194), which marked UT-A1, UT-A2 and UT-A4. Male Sprague-Dawley rats, weighing approximately 200 g, were divided into three group: control rats had free access to water, dehydrated rats were deprived of water for 3 d, and water loaded rats had free access to 3% sucrose water for 3 d before being killed. The kidneys were preserved by in vivo perfusion through the abdominal aorta with the 2% paraformaldehyde-lysine- periodate (PLP) or 8% paraformaldehyde solution for 10 min. The sections were processed for immunohistochemical studies using pre-embedding immunoperoxidase method and immunogold method. In the normal rat kidney, UT-A1 was expressed intensely in the cytoplasm of the inner medullary collecting duct (IMCD) cell and UT-A2 was expressed on the plasma membrane of the terminal portion of the shortloop descending thin limb (DTL) cells (type I epithelium) and of the long-loop DTL cells (type II epithelium) in the initial part of the inner medulla. Immunoreactivity for UT-A1 in the IMCD cells, was decreased in dehydrated animals whereas strongly increased in water loaded animals compared with control animals. In the short-loop DTL, immunoreactivity for UT-A2 was increased in intensity in both dehydrated and water loaded groups. However, in the long-loop DTL of the outer part of the inner medulla, immunoreactivity for UT-A2 was markedly increase in intensity in dehydrated group, but not in water loaded group. In conclusion, in the rat kidney, UT-A1 is located in the cytoplasm of IMCD cells, whereas UT-A2 is located in the plasma membrane of both the short-and long-loop DTL cells. Immunohistochemistry studies revealed that UT-A1 and UT-A2 may have a different role in urea transport and are regulated by different mechanisms.

• Journal of Intelligence and Information Systems
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• v.19 no.1
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• pp.125-139
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• 2013

Big data refers to the data that cannot be processes with conventional contemporary data technologies. As smart devices and social network services produces vast amount of data, big data attracts much attention from researchers. There are strong demands form governments and industries for bib data as it can create new values by drawing business insights from data. Since various new technologies to process big data introduced, academic communities also show much interest to the big data domain. A notable advance related to the big data technology has been in various fields. Big data technology makes it possible to access, collect, and save individual's personal data. These technologies enable the analysis of huge amounts of data with lower cost and less time, which is impossible to achieve with traditional methods. It even detects personal information that people do not want to open. Therefore, people using information technology such as the Internet or online services have some level of privacy concerns, and such feelings can hinder continued use of information systems. For example, SNS offers various benefits, but users are sometimes highly exposed to privacy intrusions because they write too much personal information on it. Even though users post their personal information on the Internet by themselves, the data sometimes is not under control of the users. Once the private data is posed on the Internet, it can be transferred to anywhere by a few clicks, and can be abused to create fake identity. In this way, privacy intrusion happens. This study aims to investigate how perceived personal information overload in SNS affects user's risk perception and information privacy concerns. Also, it examines the relationship between the concerns and user resistance behavior. A survey approach and structural equation modeling method are employed for data collection and analysis. This study contributes meaningful insights for academic researchers and policy makers who are planning to develop guidelines for privacy protection. The study shows that information overload on the social network services can bring the significant increase of users' perceived level of privacy risks. In turn, the perceived privacy risks leads to the increased level of privacy concerns. IF privacy concerns increase, it can affect users to from a negative or resistant attitude toward system use. The resistance attitude may lead users to discontinue the use of social network services. Furthermore, information overload is mediated by perceived risks to affect privacy concerns rather than has direct influence on perceived risk. It implies that resistance to the system use can be diminished by reducing perceived risks of users. Given that users' resistant behavior become salient when they have high privacy concerns, the measures to alleviate users' privacy concerns should be conceived. This study makes academic contribution of integrating traditional information overload theory and user resistance theory to investigate perceived privacy concerns in current IS contexts. There is little big data research which examined the technology with empirical and behavioral approach, as the research topic has just emerged. It also makes practical contributions. Information overload connects to the increased level of perceived privacy risks, and discontinued use of the information system. To keep users from departing the system, organizations should develop a system in which private data is controlled and managed with ease. This study suggests that actions to lower the level of perceived risks and privacy concerns should be taken for information systems continuance.

• Asia Marketing Journal
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• v.14 no.1
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• pp.25-51
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• 2012

Researches about the relationship between SST(Self Service Technology) and TRI(Technology Readiness Index) have been carried out after TRI was developed by Parasuraman and his colleagues(2000). We hypothesize Consumer Readiness can also influence consumer's motivation, attitude, and intent to use SST. Currently, there has been no research on this subject. In this study, we investigated the relationship between TR, Consumer Readiness and SST Core Attitudinal Model which Dabholkar & Bagozzi(1994) proposed. The researchers also investigated moderating effects of consumer traits and situational factors to verify the acceptance of such forms of service delivery by all kinds of consumers and under different situational contexts. Self consciousness, the need for interaction with an employee, and the technology anxiety were used as consumer trait variables. Perceived waiting time and perceived crowding were used as situational variables. 380 questionnaires were distributed to a sample group of people in their 20's and 30's, and the data were analyzed with structural equation model using AMOS 18.0 program. All of Cronbach's alpha values representing reliabilities were satisfactory. The values of Composite Reliability(CR) and Average Variance Extracted(AVE) also showed the above criteria, thus providing evidence of convergent validity. To confirm discriminant validity among the constructs, confirmatory factor analysis and correlations among all the variables were examined. The results were satisfactory. The results of this study are summarized as follows. 1. Optimism and innovativeness of TR partially influenced the motivation to use SST. People who tend to be optimistic use SST because of ease of use and fun. The innovative however, usually use SST due to its performance. However, consumer readiness of role clarity, ability and self-efficacy influence all the components of motivation to use SST, ease of use, performance and fun. The relative effect of consumer readiness on the motivation to use SST was much stronger and more significant than that of TR. No other previous studies have examined the effects of Consumer Readiness on SST usage motivation, attitude and intention. It is academically meaningful that the researchers verified that Consumer Readiness is the important precedent construct influencing the self service technology core Attitudinal Model. Our findings suggest that marketers should consider fun and ease of use attributes to promote the use of self service technology. In addition, the SST usage frequency will rise rapidly when role clarity, ability, and self-efficacy which anybody can easily handle SST is assured. If the SST usage rate is increased, waiting times for customers could be decreased. Shorter waiting time could lead to higher customer satisfaction. It may also result in making a long-term profit owing to the reduced number of employees. Thus, presentation of using SST by employees or videos showing how to use it will promote the usage attitude and intent. 2. In SST core attitudinal model, performance and fun factors among SST usage motivation affected attitudes of using SST. The attitude of using SST highly influenced intent to use SST. This result is consistent with previous researches that dealt with the relationship between motivation, attitude and intention. Expectation of using SST could result in good performance just like the effect of ordering menu to service employees and to have fun since fun during its use could promote more SST usage rate. 3. In the relationship among motivation, attitude and intent in SST core attitudinal model, the moderating effect of consumer traits(self-consciousness, need for interaction with service employees and technology anxiety) and situational factors(perceived crowding and perceived waiting time) were tested. The results also supported the hypothesized moderating effects except perceived crowding. The highly self-conscious tended to form attitudes to use SST because of its fun compared to those who were less self-conscious because of its performance. People who had a high need for interaction with service employees tended to use SST for its performance. This result indicates that if ordering results are assured, SST is easily accessible to even consumers who have a high need for interaction with a service employee. When SST is easy to use, attitudes strengthen intent among people who had a high level of anxiety of technology. People who had low technology anxiety formed attitudes to use SST because of its performance. Service firms must ensure their self service technology is designed to be easy to use for those who have a high level of technology anxiety. Shorter perceived waiting times strengthened the attitude to use self service technology because of its fun. If the fun aspect is assured, people willing to use self service technology even perceive waiting time to be shorter than it actually is. Greater perceived waiting times form higher level of intent to use self service technology than those of shorter perceived waiting times. This implies that people view self service technology as a faster alternative to ordering service employees. The fun aspect of self service technology will attract a higher rate of usage for self service technology. 4. It has been proven that ease of use, performance and fun aspects are very important factors in motivation to form attitudes and intent to use self service technology regardless of the amount of perceived waiting time, self-consciousness, need for interaction with service employees, and technology anxiety. Service firms must consider these motivation aspects(ease of use, performance and fun)strongly in their promotion to use self service technology. Ease of use, assuring absolute performance compared to interaction with service employees', and adding a fun aspect will positively strengthen consumers' attitudes and intent to use self service technology. Summarizing the moderating effects, fun is the most valuable factor triggering SST usage attitude and intention. Therefore, designing self service technology to be fun will be the key to its success. This study focused on the touch screen self service technology in fast food restaurant. Although it has its limits due to the fact that it is hard to generalize the results to any other self service technology, the conceptual framework of this study can be applied to future research of any other service site.

• Economic and Environmental Geology
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• v.8 no.2
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• pp.73-87
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• 1975

Regional unconformities have been used as boundaries of major stratigraphic units in Korea. The term "synthem" has already been propsed for formal unconformity-bounded stratigraphic units of maximum magnitude (ISSC, 1974). The unconformity-based classification of the strata in the cratonic area in Korea comprises in ascending order the Kyerim, $Sangw{\check{o}}n$, $Jos{\check{o}}n$, $Py{\check{o}}ngan$, Daedong, and $Ky{\check{o}}ngsang$ Synthems, and the Cenozoic Erathem. The unconformites separating them from each other are either orogenic or epeirogenic (and vertical tectonic). The sub-$Sangw{\check{o}}n$ unconformity is a non-conformity above the basement complex in Korea. The unconformities between the $Sangw{\check{o}}n$, $Jos{\check{o}}n$, and $Py{\check{o}}ngan$ Synthems are disconformities denoting late Precambrian and Paleozoic crustal quiescence in Korea. The unconformities between the $Py{\check{o}}ngan$, Daedong, and $Ky{\check{o}}ngsang$ Synthems are angular unconformities representing Mesozoic orogenies. The bounding unconformities of the $Ky{\check{o}}ngsang$ Synthem involve non-conformable parts overlying the Jurassic and late Cretaceous granitic rocks.

• Journal of Korean Academy of Nursing
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• v.4 no.3
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• pp.33-56
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• 1974

간호를 장래의 전문직으로 택하려고 공부하는 간호학생들은 완전한 성인으로서의 발달 과정중 후기 성년기에 속한다. 이시기는 자아를 발견하고 인간이 무엇을 믿으며 인간의 가치가 무엇인가를 추구하는 중요한 시기이다. 다시 말해서 어른과 어린이의 과도기에 서서 자신의 이상적 가치와 기성사회의 기존 가치를 잘 융화시켜 독립된 인간으로서 성숙하려는 노력의 시기이다. 그러므로 성년기의 갈등은 인생의 어느 시기보다도 그 정도가 심하게 나타난다. 간호학생들은 이상의 일반적인 성년기 발달의 요구 외에도 간호대학이라는 특수한 배움의 여건 때문에 좀 더 심각한 문제에 대두된다. 특히 소아과 간호대학이라는 실습환경은 여러 가지 복잡한 병실 사정으로 많은 긴장감을 주는 학습경험이다. 어린이의 간호에는 그들의 발달과정에 따른 다양한 역활이 요구된다. 또한 병원이라는 낯선 환경과 어머니를 떨어져야하는 두려움으로 불안한 어린이와 그 어린이의 불안과 두려움으로 인해 우울과 죄의식에 있는 어머니의 간호는 여러 면에서 성년기 학생들에게 긴장감을 일으키게 하는 요인이 된다. 본 연구의 문헌조사는 주로 미국 문헌에 나타난 간호 대학생들의 성년기 성숙을 위한 발달의 요구와, 소아병실의 복잡한 여건으로 발생되는 긴장감을 다루고 있다. 문헌을 기초로 하여 저자는 긴장감을 주는 간호활동을 크게 다섯 부군으로 묶었다. 1. 어린이 환자의 신체적 간호, 2. 어린이 환자나 부모와의 원만한 대화와 상호관계를 위한 간호활동 3. 소아병실에서 요구되는 다양한 간호원의 역활 4. 어린이나 부모의 간호에 대한 의뢰심 5. 간호의 가치나 이상적 간호. 연구방법으로는 49개의 폐쇄식 질문 항목을 가진 질문지를 사용하였다. 질문 항목들은 문헌연구에서 소아과 간호학 실습시 학생들이 긴장감을 느낀다고 밝혀진 내용들이 다. 학생들은 자신의 경험을 "긴장감이 없었다. ""긴장감이 있었다. ""심한 긴장감이 있었다. ""실습 중 경험이 없었다. "의 사항 중 택일을 하게 되어 있다. 연구대상으로는 모 대학교 간호대학 학생으로 산부인과 간호학 실습을 마친 후 소아과 간호학 실습 8주를 완료한 4학년 학생 42명이었다. 자료분석의 결과는 대부분의 학생들에게 소아과 간호학 실습은 긴장감을 주는 경험이 있다고 나타났다. 다음은 연구결과 주목할만한 몇 가지 사항들이다. 1. 어린이 환자의 신체적 간호는 성년기 학생들에게 긴장감을 주는 실습 경험이었다. 특별히 심하게 긴장감을 주었던 간호활동은 어린이환자의 상태가 중한 경우로, 장기간 앓는 아이, 선천성 기형이 있는 아이, 회복이 불가능하여 죽게될 아이나 사망하는 경우의 어린이 간호였다. 이 결과는 간호학의 기본과정 즉, 기초간호학이나 내 외과 간호학 실습만으로 소아과 간호학 실습을 위한 충분한 준비가 되지 못한다는 것을 뜻 할 수도 있다. 한편, 문헌연구에서 밝힌바와 같이 어리고 연약해 보이는 어린이들의 신체조건이 학생들의 간호활동을 어렵게 하는 경우도 될 수 있겠다. 2. 간호학생들의 어린이 환자와의 대화나 원만한 인간관계에서의 긴장감은 이 연구결과로 평가나 제언이 힘들다. 조사결과에서 학생들은 주로 어린이의 상태가 좋지 않은 경우에 심한 긴장감을 가졌고 일반적인 간호의 경우에는 별로 긴장감이 없었다. 이것은 질병의 상태나 화제, 이야기 할 때의 상황에 따라 긴장감의 여부가 달라질 수 있다는 결론이 되겠다. 3. 소아병실에서의 다양한 역활을 수행하는 것은 비교적 긴장감이 많이 생기는 간호활동으로 나타났다. 그러나 재미있는 사실은 학생들이 간호원으로서의 전문가적인 입장에서, 환자나 보호자를 가르칠때는 별로 문제가 없었으나 어린이 기르는 방법이나 어린이 이해면에서 좀 더 잘 안다고 생각되는 어머니가 지켜 볼때의 어린이 간호에는 긴장감을 가진다는 사실이다. 이것은 Jewett의 연구에서 밝힌바와는 상반되는 결과다. 그의 연구에서 학설들은 부모나 어머니들에 의해 전문가로서 인정받고 기대되는 경우가 제일 어려운 경험이 있다고 밝혔다. 4. 어린이 환자나 그들 부모의 간호에 대한 의뢰심은 학생들에게 심한 긴장감을 주는 경험이 있다. 특히 신체적 간호에 대해 의뢰하는 경우에는 더 심한 긴장감을 준다고 표현한다. 일반적으로 부모가 병실에 상주하는 경우에는 그들의 의뢰심이 심하며 이것은 학생들에게 감당하기 힘든 긴장과 어려움을 주게된다. 왜냐하면 성년기의 학생들은 그들 자신이 먼저 타인에게서 이해받기를 원하며 또 관용을 베풀어주기를 원하는데 그것을 남에게 주어야 하는 입장은 학생들을 긴장되게 하는 실습활동인 것이다. 5. 학생들은 그들이 배운 간호의 이상이나 가치가 실습지에서의 여러 경우와 맞지 않는 것을 보았을 때 극심한 긴장감을 갖는다고 밝혔다. 의사나 병원 행정의 사실이 자신의 이상과 맞지 않는다는 것보다는 간호원의 간호업무의 차이에서 더 비판적인 반응을 보였다. 대부분의 성년기 학생들은 그들의 이상적인 간호원상을 그들의 선배나 실무 간호원 중에서 찾으려는 시기에 그들의 간호활동이 이론과 다른 점이나 학생 자신의 소아과 간호의 가치와 다른 것을 보았을 때는 심한 반감과 긴장감을 갖게된다. 이 문제는 어린 사람이 윗 어른과 함께 동료의식을 갖고 일하기 어려운 한국적 사회구조 때문에 더 심하게 긴장감을 주는 경험인지도 모른다. 선배 간호원의 전문인으로서의 권위와 어린이 환자 보호자의 어른으로서의 권위 사이에서 자신의 이상과 가치의 추구는 용이하지 않으며 내적 갈등은 어쩔수 없는 일 일 것이다. 6. 대부분 높은 백분율의 긴장 반응은 죽음이나 환자의 사망에 관련된 간호활동 항목에서 나타났다. 이 연구의 대상 학생들은 2, 3학년에서 죽음에 대한 강의를 들었지만 이 연구 결과에 의하면 충분한 학습 경험이 주어진 것 같지 않다. 어떠한 경우의 죽음에라도 어린이 환자나 그 보호자들의 심리를 잘 이해하고 반응을 잘 관찰해서 적절한 간호를 해 줄 수 있는 다양한 방법의 학습 경험이 필요하다고 보겠다. 7. 학생들의 긴장도가 어린이 간호에 더 심한가, 보호자 간호에 더 심한가를 알기 위한 비교 결과는 비교적 비슷한 정도로 나타났다. 8. 학생들의 소아과 간호학 실습시의 긴장도는 과거의 병실 실습기간의 장, 단이나 가정에서의 어린인 간호의 경험과는 별 연관성이 없었다. 연구의 대상자가 적기 때문에 단정을 하기는 힘이 들지만 소아과 간호학 실습이 다른 병실의 실습과는 분리되어서 완전히 다르게 다루어 져야만 하며 간호교육자들의 주의 깊은 관심과 노력이 필요한 실습교육이 라 하겠다. 이상의 전반적인 고찰에 의하면 한국 성년기 간호학생들의 소아과 간호학 실습은 미국의 경우와 마찬가지로 긴장감을 주는 경험이다. 문화배경의 다른 점은 무시하고라도 Davis와 Oleson이 결론한 바와 같이 "간호대 학생은 어디를 막론하고 다 같은 성격과 문제를 가지고 있다. " 앞으로 보다 효과적인 학생들의 소아과 간호학 실습을 위한 연구를 위해 다음의 몇 가지를 본 연구의 결과를 가지고 제언한다. 1. 보다 여러 지역에서 다양한 교육 방법을 가진 학교의 학생을 대상으로 한 연구의 필요성. 2. 학생들이 실습 전 선입견이나 이미 들어서 생긴 긴장감의 개입 여부를 밝힐 수 있는 연구. 3. 학생 개인의 과거 경침이 긴장감 유발에 미치는 영향을 위한 연구 4. 이 연구의 결과를 입증할 수 있는 종단적 연구. 5. 이 연구에서 나타난 긴장감이 학습 행위에 미치는 영향을 알기 위한 관찰적 연구. 이 연구를 위해 많은 도움을 주셨던 보스턴대학의 Dr. Kennedy와 연세대학의 여러 선생님께 심심한 감사를 드립니다.

• The Korean Journal of Pesticide Science
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• v.5 no.3
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• pp.1-11
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• 2001

New technologies will have a large impact on the discovery of new herbicide site of action. Genomics, combinatorial chemistry, and bioinformatics help take advantage of serendipity through tile sequencing of huge numbers of genes or the synthesis of large numbers of chemical compounds. There are approximately $10^{30}\;to\;10^{50}$ possible molecules in molecular space of which only a fraction have been synthesized. Combining this potential with having access to 50,000 plant genes in the future elevates tile probability of discovering flew herbicidal site of actions. If 0.1, 1.0 or 10% of total genes in a typical plant are valid for herbicide target, a plant with 50,000 genes would provide about 50, 500, and 5,000 targets, respectively. However, only 11 herbicide targets have been identified and commercialized. The successful design of novel herbicides depends on careful consideration of a number of factors including target enzyme selections and validations, inhibitor designs, and the metabolic fates. Biochemical information can be used to identify enzymes which produce lethal phenotypes. The identification of a lethal target site is an important step to this approach. An examination of the characteristics of known targets provides of crucial insight as to the definition of a lethal target. Recently, antisense RNA suppression of an enzyme translation has been used to determine the genes required for toxicity and offers a strategy for identifying lethal target sites. After the identification of a lethal target, detailed knowledge such as the enzyme kinetics and the protein structure may be used to design potent inhibitors. Various types of inhibitors may be designed for a given enzyme. Strategies for the selection of new enzyme targets giving the desired physiological response upon partial inhibition include identification of chemical leads, lethal mutants and the use of antisense technology. Enzyme inhibitors having agrochemical utility can be categorized into six major groups: ground-state analogues, group specific reagents, affinity labels, suicide substrates, reaction intermediate analogues, and extraneous site inhibitors. In this review, examples of each category, and their advantages and disadvantages, will be discussed. The target identification and construction of a potent inhibitor, in itself, may not lead to develop an effective herbicide. The desired in vivo activity, uptake and translocation, and metabolism of the inhibitor should be studied in detail to assess the full potential of the target. Strategies for delivery of the compound to the target enzyme and avoidance of premature detoxification may include a proherbicidal approach, especially when inhibitors are highly charged or when selective detoxification or activation can be exploited. Utilization of differences in detoxification or activation between weeds and crops may lead to enhance selectivity. Without a full appreciation of each of these facets of herbicide design, the chances for success with the target or enzyme-driven approach are reduced.

• Korean Journal of Ecology and Environment
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• v.39 no.3 s.117
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• pp.352-365
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• 2006

In order to evaluate the change of aquatic environment in the reclaimed Hwaong Reservoir, situated in the early stage after construction, this study was conducted to measure the change of precipitation, temperature, and salinity from June 2002 to January 2006. The range and mean of temperature was $-0.7{\sim}33.4^{\circ}C$ and $13.6^{\circ}C$, respectively. Temperature of upstream part rapidly changed during the transitional period; from spring to summer and from fall to winter. It showed abrupt decrease with high discharge from the streams temporarily. While, hypolimnetic temperature of upstream happened to be somewhat higher than that of surface or downstream. The range and mean of salinity was 0.3${\sim}$32.3 psu and 25.3 psu, respectively. Vertical difference of salinity was marked, and the change in the surface water was much higher than middle or bottom layers. It showed the marked difference at all stations, except for the bottom layer of upstream into which Namyang Stream flows, indicating that vertical gradient of salinity is strongly sustained in the reservoir. Salinity was changed markedly during the storm period (June${\sim}$October), and freshwater with low salinity was expanded from upstream to downstream along the surface layer. The surface of the reservoir was totally covered by the stream discharged water with a large amount of silt and low salinity during this period. The difference of temperature and salinity between the surface and bottom layer ranged $-10.6{\sim}9.7^{\circ}C$ and $-27.1{\sim}30.0$ psu, respectively. The big difference of salinity appeared with a large discharge of freshwater from the streams or large input of seawater through the gate. Salinity was negatively correlated with temperature, indicating the influence of monsoon storm events on the salinity under the whole watershed scale of this brackish reclaimed reservoir.

• The Korean Journal of Pesticide Science
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• v.4 no.2
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• pp.21-28
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• 2000

A new fourty six 2-(4-(6-chloro-2-benzoxazolyloxy)phenoxy)-N-phenylpro- pionamide derivatives were synthesized and the herbicidal activities against rice plant and barnyard grass with pre-emergence in down land were measured. The structure activity relationships (SAR) between the activities and physicochemical parameters of the substituted(X) N-phenyl group in substrates were analyzed and discussed by Free- Wilson and Hansch method from the basis on the former study (Sung. et. al., 1999). The conditions of selective herbicide activity both the barnyard grass and rice plant are shown that the optimal hydrophobicity, $({\pi})_{opt.}=1.34$ and electron donating with field effect (F<0) of meta and ortho, para-substituted mono or disubstituent on the N-phenyl ring were found to contribute significantly. The herbicidal activities against barnyard grass are roughly the same as the results in up land whereas damage to rice plant in down land more increase than that of up land. Degradation products in water are 2-(4-(6-chloro-2-benzoxazolyloxy)phenoxy)propionic acid ((A)) (obs. pKa=4.35 & obs. logP=4.77) and 6-chloro-2-benzoxazolone (B) (obs. pKa=8.40 & obs. logP=2.90). These results were supposing that the hydrolysis product of substrates, (A) is comparatively absorbed in rice plant but not in barnyard grass. And it is assumed from the SAR equations that the 2,6-dimethyl-4-methoxymethyl group substituent ($pI_{50}=5.41$, 3g/ha) is selected as the most highest herbicidal activity against barnyard grass in green house.

• Korean Journal of Environmental Biology
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• v.38 no.2
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• pp.299-307
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• 2020

This study reported on the phytoplankton community and seasonal changes in the Seoul passage section and downstream in the Han River in 2012. Field samples were collected monthly from the upper (Paldang), middle (Cheongdam), and downstream(Seongsan) areas of the Seoul passage section. Water temperature, DO, pH, and conductivity were measured at each station. All environmental factors measured were recorded similarly at the three stations. The water temperature ranged from 2 to 30℃ and the dissolved oxygen ranged from 4.8 to 9.1 mg L^-1, showing typical patterns of temperate regions. The phytoplankton cell concentrations ranged from 990 cells mL^-1 (Paldang, December) to 2.9×10⁴ cells mL^-1 (Seongsan, March), and the chlorophyll-a content showed similar patterns to the cell numbers. The phytoplankton community was comprised of 75 genera and 95 species, including 37 diatoms, 29 Chlorophyta, 11 cyanobacteria, and two dinoflagellates. The number of species that appeared seasonally varied greatly, from nine species (Paldang, May) to 35 species (Cheongdam, December). Diatoms were the most dominant in all stations and seasons, except in summer. In contrast, chlorophytes and cyanobacteria showed sporadic high numbers in the summer and fall seasons. Four diatoms Stephanodiscus hantzschii f. tenuis, S. hantzschii, Fragilaria sp., and Aulacoseira spp., a chlorophyte Actinastrum hantzschii, and a cyanobacterium Microcystis sp. were each present in proportions greater than 10%. This study provides fundamental data from phytoplankton communities and environmental factors in the Han River for understanding water quality for long-term environmental monitoring.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.727-743
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• 1996

To know the floristic composition, vortical distribution and community structure of marine benthic algae inhabiting in the intertidal and subtidal zones of Yongil Bay, east coast of Korea, the study has performed using the quadrat method along a transect line from July, 1995 to June, 1996. In this area, a total of 144 species including 2 new red algae to Korea was found: 5 blue-green, 18 green, 20 brown and 101 red algae. The representative species throughout the year were Ulva pertusa, Gelidium amansii and Symphyocladia latiuscula. Dominant species were Sargassum thunbergii in spring, U. pertusa in summer and autumn. In winter, Chondrus ocellatus and Monostroma grevillei occurred dominantly. The standing crop exhibited mean value as $185.8g/m^2$ dry weight. Maximum value was recorded in spring $(267.3g/m^2)$ and minimum was observed in winter $(93.7g/m^2)$. Shannon's species diversity (H') and evenness (J') as maximum value were recorded in spring, whereas minimum values were shown in winter. Vertical distribution, rerognized by cluster analysis based on relative coverage of the species, could be divided into two or three algal groups except spring. In general, green algae (M. grevillei, Capsosiphon fulvescens, U. pefusa, Enteromorpha compressa) and brown algae (Sargassum fulvellum, S. thunbergii) were represented in the upper and middle zone and red algae (G. amansii, C. ocellatus, S. latiuscula, Crateloupia okamurae, Pachymeniopsis eilliptica) in the lower zone. The algal community varied according to season and environmental conditions. Particularly, seasonal variation of vortical distribution seemed to be affected primarily by water temperature. Also seasonal tidal level and tolerance of algal species to desiccation appeared to be associated with it in this area.