• Journal of Science Education
• /
• v.34 no.2
• /
• pp.291-305
• /
• 2010

The aim of this study was to survey the perceptions of the elementary school teachers on the smallscale chemistry(SSC) following its training session. The teachers participating in the survey were 266 teachers in the Gyeongnam province. They were given a questionnaire that focused on the nine areas of the SSC: Needs for the teacher training and its application, its benefits, issues of safety and danger as well as treatment of environmental pollution, its economic efficiency and the development of investigative skills. The designed questionnaire was checked by an authority, and the responses to each question were tallied and analyzed. The results are as follows. The biggest problems of the traditional experimental methods as rated by the teachers were, in the order of importance, the preparation time, the legal liability of teachers for the safety and accidents, financial issues, disposal of the experimental wastes and the lack of relevant data. Since most of the teachers had not experienced the SSC lab programs in the field, they responded positively to the questions of need for its introduction and training. The implementation of the experimental SSC lab programs should proceed in the following order: introduction into the textbook, teacher training program, after-school education and the invitation of instructors. The most useful materials for the SSC program were CDs, videos, books and various printed materials, in that order. The responses regarding benefits of the SSC program included its simplicity, convenience, time savings, diversity, qualitative and quantitative aspects, integration into the regular class and use of toys. In particular, the teachers mentioned the increased safety due to the small amount of experimental reagents needed and the durability of plastic instruments. The familarity from the use of everyday tools as well as easy access to and the low-cost of the instruments were other important benefits. The teachers in general rated the educational content of the program highly, but many also found it to be average. Some pointed out the lack of sufficient discussion due to the individual or pair groupings as a potential shortcoming. The potential for development of problem solving ability and improvement of skills was rated positively. The number of teacher who rated the development of creativity positively was just over the half. As for the area of improving investigative skills, many found its assessment difficult and confusing because of the lack of its systemic definition and categorization. Based on the findings of this study, I would like to recommend the application and a wider dissemination of the small-scale chemistry lab program into the elementary school science curriculum.

• Analytical Science and Technology
• /
• v.34 no.6
• /
• pp.259-266
• /
• 2021

Cannabis (Marijuana) is one of the most widely used drugs in the world, and its distribution has been controlled in South Korea since 1976. Identification of 11-nor-Δ⁹-carboxy-tetrahydrocannabinol (THCCOOH) in urine can provide important proof of cannabis use, and it is considered scientific evidence in the forensic field. In this study, we describe a simultaneous quantitative method for identifying THCCOOH and THCCOOH-glucuronide in urine, using simple liquid-liquid extraction (LLE), and liquid chromatography-tandem mass spectrometry (LC-MS/MS). THCCOOH-D₃ and THCCOOH-glucuronide-D₃ were used as internal standards. Validation results of the matrix effect, as well as recovery, linearity, precision, accuracy, process efficiency, and stability were all satisfactory. No carryover, endogenous or exogenous interferences were observed. The limit of detection (LOD) of THCCOOH and THCCOOH-glucuronide were 0.3 and 0.2 ng/mL, respectively. The developed method was applied to 28 authentic human urine samples that tested positive in immunoassay screening and gas chromatography/mass spectrometry (GC/MS) tests. The ranges of concentrations of THCCOOH and THCCOOH-glucuronide in the samples were less than LOQ~266.90 ng/mL and 6.43~2133.03 ng/mL, respectively. The concentrations of THCCOOH-glucuronide were higher than those of THCCOOH in all samples. This method can be effectively and successfully applied for the confirmation of cannabinoid use in human urine samples in the forensic field.

• Asian Journal of Turfgrass Science
• /
• v.1 no.1
• /
• pp.7-17
• /
• 1987

The experiment with two levels of nitrogen (0. and 300kg / ha / year) and two levels of clipping height (1.5cm and 4cm) was conducted on the field during the period 3 June to 23 October 1985. Clonal lines of korean lawngrass ( Zoysia japonica Steud.) and manilagrass ( Zoysia matrella ( L.) Merr.)of Daejon origin were established in June, as individual clone in rows 30cm apart with a 40cm spacing between clones, actually 4 clones each plot. The results obtained were as follows : 1. When no nitrogen was applied to korean lawngrass, leaf blade which appeared during the August / early September period remained green for a period of about 10 weeks and even leaves emerged in late September lived for 42 days. However, leaf longevity did not exceed 8 weeks as nitrogen was applied. In contrast the leaf longevity of manilagrass which emerged during the mid - August / early September period was 11 weeks and, under the nitrogen applied, 9 weeks, indicating that the life - saen of individual leaf of manilagrass may be longer than that of korean lawngrass. Meanwhile, clipping height had no effect on the leaf longevity in both grasses. 2. During the July / August period, tiller number, green leaf number and DM weight of korean lawngrass were increased significantly with fertilizer nitrogen, but were not with two levels of clipping height. This trend was reversed after late September : no effect of nitrogen was appeared. Instead, lax clipping increased tiller number, green leaf number and DM weight. Green leaves stimulated by lax clipping resulted in the occurrance of more dead leaves in late October. 3. The increase of tiller number, green leaf number, and DM weight of korean lawngrass due to nitrogen application appeared to be of significance in early September. Unlike korean lawngrass, however, this significant increase was maintained to late October when new green leaves still emerge. Clipping height had little effect on the growth of manilagrass by early September, but since then, lax clipping stimulated leaf appearance, possibly resulting in a remained green color of manilagrass turf. 4. Among the stolons outgrown until early September, the primary stolon was not influenced by nitrogen and clipping treatments to produce only 2 - 3 stolons. However, 1st branch stolon as affected by nitrogen increased significantly, so most of stolons which occurred consisted of 1st branch stolon. 5. Until early September, stolon length obtained at nil nitrogen level was chiefly caused by lengthening the primary stolons. By applying nitrogen the primary stolons of korean lawngrass was longer than 1st branch stolons when severe clipping was involved and in turn, shorter than 1st branch stolons when lax clipping was concerned. In manilagrass, 1st branch stolons were much longer than the primary stolons when turf was clipped severely but in conditions of lax clipping, there was little difference in length between primary and 1st branch stolons. 6. Stolon nodes of both korean lawngrass and manilagrass were positively influenced by nitrogen, but no particular increases by imposing clipping height treatment was marked in manilagrass. Although the stolon of korean lawngrass was grown until late october, the growth stimulated by nitrogen was not so remarkable as to exceed that a by nil N. 7. The thickness of korean lawngrass and manilagrass was greatest in late September, but that of manilagrass did not differ significantly from that in late October. 8. The response of stolon length of korean lawngrass to lax clippings was not so great in late October as to that to severe clippings. On the other hand, the positive effect of lax clippings to stolon length in m anilagrass was confirmed even in late October.

• Korean Journal of Organic Agriculture
• /
• v.22 no.1
• /
• pp.97-113
• /
• 2014

An actual proof experiment was carried out to establish the production of high quality organic rice at farm household in Gwangjin, Junnam, Korea 2011. Experimental plot was designed with conventional organic cultivation and manual organic cultivation in both Hopeongbyeo and Onnuri varities. Experimental field was consisted with suitable drainage loam soil, anryong series, and normal paddy field. Chemical characteristics of the soil were investigated from initial soil and soil after harvest in experimental sites. Seed disinfection was treated with hot water dipping method at $60^{\circ}C$ for 10 min. Rice transplanting was carried out at 17 June with 25 days seedling using machine transplanting. Golden apple snail was used to prevent weed growth as middle size (1.5~1.7 kg/10a) at one week after rice transplanting. Amount of applied fertilizer in experimental plot was supplied with organic fertilizer for the shortage after harvest of hairy vetch (1,100 kg/10a). Bordeaux mixture was used to control of sheath blight and neck blast disease in all experimental plot at 19 Aug. Application of chitin culture solution was treated in manual organic cultivation at 2 and 15 Aug. At late growth stage, incidence rate of neck blast was the highest level at Hopyeongbyeo in conventional organic cultivation. Incidence rate of sheath blight in both Hopyeongbyeo and Onnuri was higher in conventional organic cultivation than in manual organic cultivation. Incidence of rice leaf folder was the highest level at Onnuri in conventional organic cultivation. Yield index in manual organic cultivation was increased by 13% and 38% at Onnuri and Hopyeongbyeo, respectively, compared with conventional organic cultivation. Head rice percentage in both Hopyeongbyeo and Onnuri was slightly increased in manual organic cultivation. These results indicate that high quality production of rice organic cultivation could be depending on management of safe fertilization with nutrient content in soil.

• Korean journal of applied entomology
• /
• v.10 no.2
• /
• pp.109-116
• /
• 1971

The study involved determination of resistance levels of spider mites to Metasystox, Folidol and C-8514 using slide dip technique: a feid trial of alternative acaricides using an O/P resistant strain. 1. Resistant strains of two-spotted spider mite( Tetranychus urticae Koch) were collected from Taegu, Kyungsan, Chunchun, Yesan, Suwon, Osan and Chungju, and kept in the glasshouse through the experiments. Resistant strains of European red mite (Panonychus ulmi Koch) were collected from Chungju, Taegu, Yesan, Chunchun, Suwon and Whasung, and Wonju susceptible was collected. Immediately after collection, tests were applied. All strains except susceptible populations had regularly been sprayed with Organo-phosphates including Parathion (or Folidol), Metasystox, Phenkapton and Trithion for more than the ten Bast years; and Organo-chlorines such as Kelthane and C-8514 more than five years. Comparisons of the resistant strains and susceptible strains at the $LC_50$ values are as follows: a. With Metasystox, resistance levels of the Chungju, Taegu, Yesan, Chunchun and Suwon resistant strains of P. ulmi were respectively, 96,52,4,3 and 2, times as resistant as the Wonju susceptible strain. b. With Folidol, resistance levels of the Chungju, Chunchun, Yesan, Whasung and Suwon strains of P. ulmi showed respectively, 126, 48, 33, 30 and 6-fold resistance levels over the susceptible strain. c. With C-8514, resistance levels of the Taegu, Suwon, Whasung and Chungju strains of P. ulmi were 42, 31, 30 and 20 times greater than the susceptible strain, respectively. d. With Metasystox, resistance levels of the Taegu, Chunchun, Yesan and Suwon, strains of T urticae were respectively, 32,29,25 and 17 times as resistant as the susceptible strain. e. With C-8514, resistance levels of the Taegu, Chungju and Kyungsan strains of T. urticae showed respectively, 59, 29 and 19-fold resistance levels over the Osan strain. 2. Field trials were carried out to assess the toxicities of eleven alternative materials which would be used for control of O/P resistant strain of Panonychus ulmi. The acaricide groups represented were 2 Organo-chlorines (Kelthane MF and Prethylen), 1 carbamate (Furadan), 1 nitrophenyl (Morocide), 1 carbonate (Morestan), 1 tin(Plictran), 1 fluorine (Nissol), 2 mixtures (Fundal and Banmite) and Organo-phosphate (Phenkapton). Of all acaricides tested Kelthane, Plictran, Fundal and Morestan were the most effective; fol]owed by Banmite, Furadan, Prethylen and Nissol. Sumite and Morocide were intermediate, but Phenkapton(Organo-phosphate) was very poor. In other words, a first application of the above outstanding materials gave very high degrees of control of O/P resistant population of European red mite for about 7 to 12 days. However, the results indicate that secondary application would sometimes be necessary. There was no foliage damage to apple trees by any of the acaricides tested of the concentrations used.

• Journal of Korean Society of Forest Science
• /
• v.78 no.2
• /
• pp.177-188
• /
• 1989

The habitat typing method of classification based on community has been developed on many forested areas in the ROCKY MOUNTAINS of WESTERN NORTH AMERICA, and is being used in providing an objective principle of guide for classification of forest sites, land classification, vertical distribution and multipurpose management of forest. I actually made a trial of forest habitat type classification - The methodology can be segmented into a number of tasks including reconnaissance, selection of stands to be sampled, location of plots, data gathering, preliminary and computer analysis, preparation of key- and map of habitat type and description for each habitat type in a view of forest management - on UNIVERSITY OF MONTANA FORESTS in order to examine whether its application is fit or not in korean forest circumstances : these are composed mainly of artificial forest and forest in the early stage of succession. The main results obtained from this study were summarized as follows 1. A hierarchical classification-Climax, Habitat type and Phases-of forest sites was developed using the habitat typing method of classification. 2. A diagnostic key is provided for field identification of the types based upon presence and number of indicator species, and forest managers could prepare a map of habitat type and classify forest habirat types by reference to it. 3. The classified habitat types were considered to be effective on providing an objective principle of guide for multipurpose management of forest including potential productivity for timber, feed productivity of forage and wildlife, selection of the right species in the right sites, application of method of treatment and so forth. 4. Forest habitat type classifications based upon extrapolation which used relict species and associated stands is considered to be suitable for korean forest circumstances and objective in studying potential vegetation, vertical and horizontal distribution of forest.

• Korean Journal of Weed Science
• /
• v.7 no.2
• /
• pp.208-219
• /
• 1987

Newly developed several herbicides were evaluated as paddy rice herbicide at the Yeongnam Crop Experiment in 1986. And also, the general situation of rice cultivation between Korea and Japan was compared. Twenty-nine herbicides of the total 59 herbicides were used as paddy rice field in Korea while these were 100 and 187, respectively, in Japan. Among paddy rice herbicides, butachlor was the most important herbicide in both countries. However, the degree of concentration to a particular herbicide was greater in Korea compared to Japan; consumption rate of single butachlor to the total herbicide were 66.5% for Korea and 11.9%r for Japan, respectively. Pyrazolate, pyrazoxyfen and quinclorac were the most promising hebicides in pressed-type rice nurserybed in terms of herbicidal efficacy and phytotoxic effect. For transplanted paddy rice field, single application of NC-311 or combining applications of NC-311 with butachlor or quinclorac gave excellent results at the weed community that was dominated by Echinochloa crus-galli, Aneilema japonica, Ludwigia prostrata, Scirpus hotarui, Cyperus serotinus, Potamogeton distinctus and Eleocharis kuroguwai. Particularly the above combining applications maintained their excellent herbicidal effect up to 3 leaf stage of E. crus-galli without arising herbicidal phytotoxicity. Pyrazolate and three sulfonyl urea herbicides (DPX-5384, NC-311 and CGA 142464) exhibited very high safety against rice. However, Japonica type rice cultivar was a little bit more sensitive than Indica/Japonica type rice cultivar. On the other hand, the effect of these herbicides against E. crus-galli was very strong. Herbicidal effect against E. crus-galli was enhanced through shoot absorption for sulfonyl urea herbicides and root abosorption for pyrazolate and quinclorac, respectively.

• The Korean Journal of Pesticide Science
• /
• v.21 no.1
• /
• pp.84-89
• /
• 2017

This study was carried out to investigate residue dissipation of fluquinconazole and flusilazole in field-sprayed tomatoes during greenhouse cultivation and processing. The test pesticide, fluquinconazole+flusilazole 8.5 (7+1.5)% SC, was sprayed onto the tomatoes growing in a greenhouse according to Korea preharvest intervals and then samples were collected on 0 (3 hours after spraying), 1, 3, 5 and 7 days after last application for decline test. For processing test, tomatoes collected at harvest on 5 day after last application were processed to puree and juice. Limits of quantitation of fluquinconazole and flusilazole were 0.005 mg/kg in both tomatoes and their processed products. Recoveries for validation of the analytical methods for fluquinconazole and flusilazole in tomatoes and their processed products ranged from 74.8 to 97.5%. Biological half-lives of fluquinconazole and flusilazole in tomatoes under greenhouse conditions found to be 5.2 and 6.4 days, respectively. Average persistent residue levels of fluquinconazole and flusilazole were 37.34 and 79.53% after washing, 8.95 and 28.75% in filtrates after boiling, 3.58 and 14.66% in puree, and 3.34 and 13.52% in juice, respectively. These results indicated that the test pesticide residues on tomatoes could be largely removed through washing and boiling.

• Journal of Korean Society of Forest Science
• /
• v.81 no.1
• /
• pp.53-65
• /
• 1992

For elucidating effective methods of restoration of forest recreational sites where management goals are maintaining naturalness and conserving natural ecosystem, seeding, fertilization and soil surface treatment were used for four years at the devastated forest-floor. For restoration of forest-floor vegetation, factorial experiment was used with a split plot design(main plot : fertilization, subplot : soil surface${\times}$seeding) and a randomized complete block design (fertilization${\times}$seeding) at the Kwanaksan Aboretum, Anyang, Kyonggido. Results were summarized as follows : Soil surface softening with tipping and ripping and straw-mat mulching (70% coverage) treatment was effective on germination, survival and growth of seeded vegetation at devastated forest-floor. Especially, straw-mat mulching treatment was effective on soil surface stabilization and seedling's survival at eroded soil surface, while complete soil surface softening treatment was effective on germination, survival and early growth of tree species of late-successional series. Introducing seeds of native species of pioneer or early-successional series, with good growth capability in barren soil was effective on rapid restoration in devastated forest-floor with its soil surface previously compacted and its surviving seeds washed away. When the seeding and straw-mat mulching after partial soil surface softening with tipping and ripping treatment were employed, it took about three years to restore the devastated forest-floor where surface erosion had been undertaken for an extended period of time and where naturally surviving seeds of native species had been washed away. Softening treatment of soil surface was effective for about two years, and seeding and soil surface treatment increased number of seedlings and improved soil surface environment through fixing of movement of the fallen leaves. Fertilizing effect was not oberserved, mainly due to seeding exposure and poor physical condition including soil surface erosion, low soil water potential and drought, etc, at the field experimental site. However, application of nitrogen and phosphate fertilizers was effective on seedling survival of the species in late-successional series, while lime application adversely affected the seedling survival.

• Korean Journal of Soil Science and Fertilizer
• /
• v.25 no.1
• /
• pp.38-43
• /
• 1992

A field experiment was conducted to find out the effect level of nitrogen fertilization on the yield and quality of hop (Hallertau variety) emphasis given to ${\alpha}$-acid content. Nitrogen was applied by the rates of 0, 12, 18, 24, 30 and 36kg per 10a. Results were summarized as follows. 1. Stages of cone-hair developing and coneripening were delayed with increment of nitrogen applied. Number of nodes and length of vine increased with nitrogen applid by up to 24kg N/10a. 2. Yield was the highest in the 24kg N/10a plot and cone weight had high significant correlations with yield without regard to the years of growth. No.of flower per side blanch and weight of 100 cones had a significant correlation with yield in the four-year old and five-year old Hop plants. 3. Nutrient content in Hop plants was in the order of CaO, total nitrogen, $K_2O$, MgO and $P_2O_5$. Content of total nitrogen, CaO and MgO was high in leaves while that of $P_2O_5$ and $K_2O$ was high in cone. Nitrogen, phosphorus and magnesium increased with increment of nitrogen fetilized while potassium and calcium decreased. 4. As for the distribution of nutrients in cone developing stage $SiO_2$ content was higher in lower part than in the upper part while $P_2O_5$ contetn was higher in upper part than in lower part of the plant. And content of nitrogen and potassium was higher in middle height than in upper and lower part. 5. The optimum levels of nitrogen application were 19.3kg for 2 years, 24.3kg for 3-year, 27.9kg for 4 years and 31.8kg/10a for 5-year old Hop, respectively. 6. Nitrogen uptake in cone showed a positive correlation with the content of ${\alpha}$-acid and ${\beta}$-acid in cone.