• The Korean Journal of Pesticide Science
• /
• v.11 no.2
• /
• pp.106-116
• /
• 2007

Pesticide, chlorfluazuron was subjected to determine the safety of terminal residues at the harvesting date of perilla leaves cultivated in plastic house. After the pesticide applied on a foliar spray in 2005 and 2006, leaf persistence of its residue was analysed for 10 days before leaf harvest. The degradation rate of chlorfluazuron in the leaf was 32.3 %(standard application), 43.6 %(double application) and 78.0 %(standard), 80.4 %(double) at second and tenth day, respectively, under analysis of GC/ECD in 2005. The degradation rate of chlorfluazuron in the leaf was 33.1 %(GC/ECD analyze), 34.0 %(HPLC/UVD analyze) and 77.9 %(GC/ECD), 78.4 %(HPLC/UVD) at second and tenth day, respectively, under the standard level of pesticide in 2006. The biological half-life of the chlorfluazuron residue was estimated by the regression equation calculated from daily dissipation of pesticide in the perilla leaves. The longest half-life of the chlorfluazuron residue in perilla leaves was 5.5 days. The maximum residual limit(MRL) for chlorfluazuron based on the longest half-life was estimated 2.0ppm at harvesting day, 2.5ppm at second day and 7.1ppm at tenth day before leaf harvesting of perilla.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1994.04a
• /
• pp.201-201
• /
• 1994

항암 및 면역조절작용을 가지고 있으며 그자체가 서방성 prodrug으로서 약효를 나타낼것으로 기대되는 ara-C와 etherphospholipid의 conjugate인 ara-CDP-DL-PCA.2Na의 실험동물(rat)에서의 체내동태를 HPLC 정량법으로 시행 하였다. Ara-CDP-DL-PCA.2Na의 정맥내 투여(20mg/300g)의 경우 혈장중 반감기는 분포상에 있어서는 평균 20min, 소실상 에서는 4.42hr이었다. 분포 용적은 0.1635Lㆍkg$^{-1}$이었고, 전신 clearance 는 25.63ml.$hr^{-1}$.kg$^{-1}$이었다. 한편 AUC는 2601$\mu\textrm{g}$.hr.ml$^{-1}$이었다. 복강내 주사(1g/kg)의 경우 소실상의 반감기는 3.28hr, AUC는 439.3$\mu\textrm{g}$.hr.ml$^{-1}$이었다. 최고 혈중농도 도달시간은 4.4hr이었으며 그때의 농도는 33.19$\mu\textrm{g}$.ml$^{-1}$이었다. 한편 흡수속도 정수는 0.2493$hr^{-1}$이었다. 정맥내 투여에 대한 복강내 투여의 생체 이용율은 1.1252%로 복강내 투여시 흡수율이 좋지 않음을 시사하고 있다. 이는 투여 시료인 micellar solution이 일종의 약물저장 형태로 작용하여 활성물질을 서서히 방출 하기 때문인 것으로 사료된다. 한편 예비적 대사연구결과 TLC에서 뇨나 담즙으로 배설되는 유의한 농도수준의 ara-CDP-DL-PCA.2Na가 없는 것으로 평가되었다. 이는 생체내에서 enzyme등에 의한 대사과정을 거치는 것으로 사료되는바 방사성 동위원소 표지화합물을 이용한 충분한 대사연구가 필요한 것으로 사료된다.

• Journal of the Korean Society for information Management
• /
• v.11 no.2
• /
• pp.31-48
• /
• 1994

This study attempts to investigate the scatter of citation, obsolescence, and half-life of some social science literature. For the study 131 journal articles taken from three scholarly journals in the field of Economics. Public Administration, and Library and Information Science are selected and all analyses are taken in terms of the material types, the publication place, and the publication year of the papers cited by those journal articles. In result, it was found that the half-life of monographs is 6.76, that of scholarly journal articles 8.07, that of reports 6.49, and that of theses 3.45. Also, the study finds that most researchers in those field, cited more articles published in foreign countries(67.79%) that those published from Korea(32.21%).

• Korean Journal of Environmental Agriculture
• /
• v.21 no.3
• /
• pp.172-177
• /
• 2002

Photodegadation rates of carbofuran in aqueous solution were measured under various test conditions mainly following the guidelines of U.S. EPA and OECD. Half-lives of carbofuran in distilled water were 9.7 days. 3.3 days, and 1 hr under natural sunlight, SUNTEST with UV filter, and SUNTEST without UV filter, respectively. Waters from a paddy field accelerated the decomposition by factor of 6. It was confirmed that the use of SUNTEST could shorten the test period of photodegradation.

• Journal of the Korean Society for information Management
• /
• v.28 no.2
• /
• pp.97-115
• /
• 2011

A large and reliable citation database is necessary to identify and analyze citation behavior of Korean researchers in science and technology. Korea Institute of Science and Technology Information (KISTI) built the Korea Science Citation Database (KSCD), and have provided Korea Science Citation Index (KSCI) and Korea Journal Citation Reports (KJCR) services. In this article, citing behavior of Korean scientists on Korean journals was examined by using the KSCD that covers 459 Korean core journals. This research dealt with (1) statistical numeric information of journals in KSCD, (2) analysis of document types cited, (3) ratio of domestic to international documents cited and ratio of citing different disciplines, (4) analysis on immediacy index, peak time, and half-life of cited documents, and (5) analysis on impact of journals based on KJCR citation indicators. From this research, we could find the immediacy citation rate (average 2.36%), peak-time (average 1.7 years) and half-life (average 5.2 years) of cited journals in Korea. We also found that the average journal self-citation rate is more than 50% in every field. In sum, citing behavior of Korean scientists on Korean journals was comprehensively identified from this research.

• Journal of Applied Biological Chemistry
• /
• v.55 no.4
• /
• pp.235-239
• /
• 2012

While cultivating crops, it is important to predict the biological half-lives of applied pesticides to ensure the safety of agricultural products. Dissipation patterns of the triazole fungicides, such as diniconazole and metconazole, during the cultivation of apple were established by utilizing the dissipation curve. As well as, the biological half-lives of the pesticides in apples were calculated using the residue amounts of them. The apples were harvested from 0 to 14 days after spraying diniconazole (WP) and metconazole (SC) at a recommended and three times of the recommended dose. Initial concentrations of diniconazole in apple were 0.09 and 0.15 mg/kg at a recommended and three times of the recommended dose, respectively, which were below MRL 1.0 mg/kg established by KFDA. The equations of biological half-life were $C_t=0.0811e^{-0.179x}$(half life: 3.9 days) and $C_t=0.1451e^{-0.148x}$ (half life: 4.7 days), respectively. In case of metconazole, initial concentrations in apple were 0.10 and 0.25 mg/kg, below MRL 1.0mg/kg, and biological half-life equations were $C_t=0.0857e^{-0.055x}$ (half life: 12.6 days) and $C_t=0.2304e^{-0.052x}$ (half life: 13.3 days), respectively. Therefore, when triazole fungicides were applied during the cultivation of apple, the biological half-life need to be calculated with the optimal equation model.

• Applied Biological Chemistry
• /
• v.47 no.1
• /
• pp.113-119
• /
• 2004

Persistence of the triazole fungicides, bitertanol and tebucnazole was investigated after their application at recommended and double rate on greenhouse-grown peppers. The half-life of bitertanol and tebuconazole on peppers at recommended and double rate was $5.2{\sim}6.1$ and $4.6{\sim}5.2$ days, respectively. Half-lives of bitertanol and tebuconazole on pepper leaves $(16.8{\sim}22.5\;days)$ was longer than those in the peppers. Residual concentration of bitertanol and tebuconazole on pepper leaves 24 days after application were 10.1 and 17.5 mg/kg, respectively, and these levels were higher than MRL which had been established at 3.0 and 5.0 mg/kg in Korea. Pattern of dissipation was well fitted to the first-order kinetics. In household washing experiment with surfactant, dislodgeable portions on pepper leaves of bitertanol and tebuconazole were occupied 36% and 48% of the residues found 24 days after application.

• Korean Journal of Weed Science
• /
• v.4 no.2
• /
• pp.154-162
• /
• 1984

The persistence of butachlor and nitrofen in different soil conditions applied organic matter, lime, and other pesticides was studied under submerged and field moisture capacity. Degradation of the herbicides in soil was significantly retarded by autoclaving the soil and half-life of nitrofen was much longer than that of butachlor under this condition. Submerging the soil enhanced degradation of the herbicides, in particular that of nitrofen. On the other hand, half-life of nitrofen under field moisture capacity was twice longer than that of butachlor. Increased amendment of rice straw to the soil shortened the half-life of nitrofen under submerged soil, however it prolonged that of butachlor when the amendment was exceeded 1000kg/10a level. Liming the soil stimulated herbicide decomposition in the soil, which appears to be pH independent. Butachlor degradation in submerged soil was slightly stimulated by simultaneous application of fungicides and insecticides, but nitrofen persistence was not influenced.

• Analytical Science and Technology
• /
• v.13 no.6
• /
• pp.722-730
• /
• 2000

The residual concentration and half-life time of synthetic pyrethroid insecticide cyfluthrin in potato and soil were investigated by gas chromatography (GC). The pesticide in potato was extracted with n-hexane, filtered and concentrated. The concentrated phase was transferred to the Sep-Pak silica gel column and purified with acetonitrile and acetone for the analysis by gas chromatography equipped with electron capture detector (GC-ECD). From the standard additional experiments with 0.01 and $0.1{\mu}g$, the recoveries were 85-87% and the detection limit was 0.005 ng. The soil sample was extracted with acetone and dichloromethane. The organic phase was concentrated and redissolved with n-hexane and analyzed with GC-ECD after cleaned with Sep-Pak column. From the standard additional experiments with 0.01 and 0.1 ng, the recoveries were 84-88% and the detection limit was 0.005ng. The half-life time of cyfluthrin in the silty clay was 25 days in the room laboratory and 0.6 days in the fieJd test whereas it was 38 days and 0.5 days for each in case of silty loam.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.11 no.1
• /
• pp.1-12
• /
• 2012

Even though the semi-actuated signal control system based on image detectors has been spreading in Korea, any appropriate methods to evaluate the effectiveness and performance has not been established yet. Therefore, this research effort is aiming at developing a systematic method for evaluating the effectiveness and performance of the semi-actuated signal control system based on image detectors. To this end, this research firstly established measures of effectiveness(MOEs) and associated information to be surveyed from fields. Secondly, this research provided a procedure and methodology to evaluate any improvements due to the introduction of a semi-actuated signal control system based on image detectors. The developed methodology was examined at a case study site located in the city of Paju. As a result of the evaluation, the MOEs including traffic throughput, travel speeds, split usage rate, progression rate, etc. showed positive improvements though individual signalized intersections as well as coordinated corridors.