• Korean Journal of Agricultural Science
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• 제8권2호
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• pp.203-211
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• 1981

Mechanization of rice transplanting operation is very important project not only to solve the labor shortage problem at the so-called labor demand peak seasons of the rice transplanting, but also to reduce the production cost of rice by reducing the labor requirements. For these reasons this study was carried out to find the basic data for encourage the project of mechanization of rice transplanting. 381 sample farms were surveyed with questionaries and interviewed with a considerable number of relative personels about the operation, selecting and ownership trend of the rice transplanter. Collected data was analized by computer of Chungnam National University computer center applied to frequencies, cross- tabulation, $x^2$-test. The analized results of this survey are summarized as follows; 1. About 76.09% of the farmers interviewed was individual ownership of rice transplanter but about 52.27% of the farmers who wanted to purchase it in 2 or 3 years supported the cooperative ownership and utilization. This fact suggested that cooperative system of village level should be thoroghly studied. 2. The 93.33% of respondents gave the answer that the yield of rice was not affected by the planting methods between machine and manual. 3. The farmers who had a rice transplanter owned 4- row type rice transplanter with mat type seedling but the 25% of the farmers wanted to purchase it in 2 or 3 years wanted to own a 4 row type rice transplanter with band type seedling. Therefore the introduction of the 4-row type rice transplanter with band type seedling to rural area should be considered again. 4. The percent of farmers who wanted the cooperative system of village level was 49.57-57.83% of the farmers who had it already and wanted to own it in near future. It was strengthened by this fact that seedling nursely work was technically supported by the governmental level.

• Journal of Korean Society of Forest Science
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• 제51권1호
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• pp.22-35
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• 1981

This study was designed to know difference in degree of dehardening and rehardening respectively by artificial high and low temperature treatments among different clonal seedlings and seedlings from different seed sources of Cryptomeria japonica which have been grown under the cold areas in Japan and Korea. High temperature treatment was done with 15 to $20^{\circ}C$ under 100% relative humidity for one to nine days and low temperature treatment was carried with $-7^{\circ}C$ for one to three days. Occasionaly, high temperature treatment was combined and followed by low temperature treatment. The ability of stem section to delay dehardening by high temperature treatment and/or to hasten rehardening by low temperature treatment was used as an indicator of adaptability under extreme temperature fluctuation in nature. Clones and seedlings from different seed sources which showed greater freezing resistance than others after artificial high and/or low temperature treatments were selected over two to three time periods: early winter, mid winter and early spring in 1977 to 1980. These were Seoul #7, and #9, Namboo #3, and #4, Sung-Kang #11, Chung-Sam #8 and Huek-Suk #9. These selected seedlings might have survival advantage to withstand early and late frost damage, especially the critical frost damage of the basal stem, since it was known to be induced by lowering freezing resistance of the basal part when exposed to the high temperature near the ground during the day. Large variation in freezing resistance and degree of dehardening and rehardening was found among clonal or seed sources and among individuals within a seed source, but was not related to the difference in climatic conditions where the parent trees was selected. These indicated the possibility of future breeding work for more cold resistant family of Cryptomeria japonica.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• 제8권3호
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• pp.285-294
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• 2003

To select an appropriate sampler for the environmental monitoring survey in coastal waters of Saemangeum, Jeollabuk-do, a macrobenthic sampling was conducted in April 2002. Employed samplers were dredge (type Charcot), a semi-quantitative sampler and Smith-McIntyre (SM) and van Veen grab (VV) as quantitative ones. One haul was tried for dredge and 3 replicates (0.1 ㎡${\times}$3) for SM and W at each of 11 stations. Comparisons of sediment volume in sampler bucket and of precision of biological parameters (i.e., density, biomass, species number and diversity index, H') were made between SM and VV. Sediment volume was significantly different (SM > VV) at p-value of 0.0050 (paired t-test) and, in average, 3 replicate samples of SM and VV satisfied a precision level of 0.2 by applying 4th root transformation. Patterns of observed and expected species numbers and H' were compared. Dredge-VV samples showed higher affinity than any other pair. Several dominant species in the area were underestimated in dredge samples (e.g., polychaete Heteromastus filiformis. Aricidea assimilis etc.). Quantifying the agreement pattern of multi-species responses was accomplished by estimating correlations between similarity matrices. Correlation between dredge and VV was slightly higher, but near-per-fect matches were found in general. Different ranks and composition among principal species lists were presumably linked to the effect of penetration depth that differs among samplers. Lower level of some species' abundance in VV samples (ca. 50％ compared with those of SM) was explained in this context. It seem appropriate to regard the effect as a probable cause of relatively higher correlations in dredge-VV, Overall bio-logica1 features indicated that a better choice could be SM in situations of requiring high data quality. The others work well, however, on observing and defining faunal characteristics and their capability cannot be questionted if we do not expect a first-order quality.

• Parasites, Hosts and Diseases
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• 제30권2호
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• pp.65-74
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• 1992

The tegumental ultrastructure of juvenile and adult Echinostoma cinetorchis (Trematoda: Echinostomatidae) was observed by scanning electron microscopy. Three-day (juvenile) and 16-day (adult) worms were harvested from rats (Sprague-Dawley) experimentally fed the metacercariae from the laboratory-infected fresh water snail, Hippeutis cantori. The worms were fifed with 2.5% glutaraldehyde, processed routinely, and observed by an ISI Korea DS-130 scanning electron microscope. The 3-day old juvenile worms were elongated and ventrally curved, with their ventral sucker near the anterior two-fifths of the body. The head crown was bearing 37∼38 collar spines arranged in a zigzag pattern. The lips of the oral and ventral suckers had 8 and 5 type II sensory papillae respectively, and bewteen the spines, a few type III papillae were observed. Tongue or spade-shape spines were distributed anteriorly to the ventral sucker, whereas peg-like spines were distributed posteriorly and became sparse toward the posterior body. The spines of the dorsal surface were similar to those of the ventral surface. The 16-day old adults were leaf-like, and their oral and ventral suckers were located very closely. Aspinous head crown, oral and ventral suckers had type II and type III sensory papillae, and numerous type I papillae were distributed on the tegument anterior to the ventral sucker. Scale-like spines, with broad base and round tip, were distributed densely on the tegument anterior to the ventral sucker but they became sparse posteriorly. At the dorsal surface, spines were observed at times only at the anterior body. The results showed that the tegument of E. cinetorchis is similar to that of other echinostomes, but differs in the number and arrangement of collar spines, shape and distribution of tegumenal spines, and type and distribution of sensory papillae.

• Korean Journal of Agricultural and Forest Meteorology
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• 제17권2호
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• pp.108-125
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• 2015

The agro-climatic index is one of the ways to assess the climate resources of particular agricultural areas on the prospect of agricultural production; it can be a key indicator of agricultural productivity by providing the basic information required for the implementation of different and various farming techniques and practicalities to estimate the growth and yield of crops from the climate resources such as air temperature, solar radiation, and precipitation. However, the agro-climate index can always be changed since the index is not the absolute. Recently, many studies which consider uncertainty of future climate change have been actively conducted using multi-model ensemble (MME) approach by developing and improving dynamic and statistical downscaling of Global Climate Model (GCM) output. In this study, the agro-climatic index of Korean Peninsula, such as growing degree day based on $5^{\circ}C$, plant period based on $5^{\circ}C$, crop period based on $10^{\circ}C$, and frost free day were calculated for assessment of the spatio-temporal variations and uncertainties of the indices according to climate change; the downscaled historical (1976-2005) and near future (2011-2040) RCP climate sceneries of AR5 were applied to the calculation of the index. The result showed four agro-climatic indices calculated by nine individual GCMs as well as MME agreed with agro-climatic indices which were calculated by the observed data. It was confirmed that MME, as well as each individual GCM emulated well on past climate in the four major Rivers of South Korea (Han, Nakdong, Geum, and Seumjin and Yeoungsan). However, spatial downscaling still needs further improvement since the agro-climatic indices of some individual GCMs showed different variations with the observed indices at the change of spatial distribution of the four Rivers. The four agro-climatic indices of the Korean Peninsula were expected to increase in nine individual GCMs and MME in future climate scenarios. The differences and uncertainties of the agro-climatic indices have not been reduced on the unlimited coupling of multi-model ensembles. Further research is still required although the differences started to improve when combining of three or four individual GCMs in the study. The agro-climatic indices which were derived and evaluated in the study will be the baseline for the assessment of agro-climatic abnormal indices and agro-productivity indices of the next research work.

• Proceedings of the Korean Environmental Health Society Conference
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• 한국환경보건학회 2003년도 Challenges and Achievements in Environmental Health
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• pp.24-25
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• 2003

Lead is ubiquitous in the human environment as a result of industrialization. China's rapid industrialization and traffic growth have increased the potential for lead emissions. Lead poisoning in children is one of the most common public health problems today, and it is entirely preventable. Children are more vulnerable to lead pollution and lead in their bodies can affect their nervous, circulatory, and digestive systems. Children are exposed to lead from different sources (such as paint, gasoline, and solder) and through different pathways (such as air, food, water, dust, and soil). Although all children are exposed to some lead from food, air, dust, and soil, some children are exposed to high dose sources of lead. Significant sources of lead for China's children include industrial emissions (often close to housing and schools), leaded gasoline, and occupational exposure that occurs when parents wear lead-contaminated clothing home from work, burning of coal for home heat and cooking, contaminated food, and some traditional medicines. To assess the blood lead level in children in China, a large-scale study was conducted in 19 cities among 9 provinces during 1997 to 2000. There were 6502 children, aged 3-5 years, were recruited in the study The result indicates that the mean blood lead level was 8.83ug/dl 3-5 year old living in city area. The mean blood lead level of boys was higher than that of girls (9.1l ug/dl vs 8.73ug/dl). Almost 30 percent childrens blood lead level exceeded 10ug/dl. The average blood lead level was higher than that of in 1985 (8.83ug/dl vs 8.lug/dl). An epidemiological study was carried on the children living around the cottage industries recycling the lead from battery. Nine hundreds fifty nine children, aged 5-12 years, living in lead polluted villages where the lead smelters located near the residential area and 207 control children live in unpolluted area were recruited in the study. The lead levels in air, soil, drinking water and crops were measured. The blood lead and ZnPP level were tested for all subjects. The results show that the local environment was polluted. The lead levels both in the air and crops were much higher than that of in control area. In the polluted area, the average blood level was 49.6ug/dl (rang 19.5-89.3ug/dl). Whereas, in the unpolluted area, the average blood level was 12.4ug/dl (rang 4.6-24.8ug/dl). This study indicates that in some countryside area, some cottage industries induce seriously lead pollution and cause children health problem. For the introducing of unleaded gasoline in some large cities, such as Beijing and Shanghai, the blood lead level showed a declined trend since 1997. By 2000, the use of leaded gasoline in motor vehicles has been prohibited in China. The most recent data available show that levels of lead in blood among children in Shanghai decreased from 8.3ug/dl in 1997 to 7.6ug/dl in 1999. The prevalence rate of children lead poisoning (blood lead >10ug/dl) was also decreased from 37.8% to 24.8%. In children living in downtown area, the blood lead level reduced dramatically. To explore the relationship between gene polymorphisms and individual susceptibility of lead poisoning, a molecular epidemiological study was conducted among children living in lead polluted environment. The result showed that the subjects with ALAD2 allele has higher ZPP level, and the subjects with VDR B allele has larger head circumference than only with b allele. In the present study, we demonstrated that ALAD genotypes modify lead effects on heme metabolism and VDR gene variants influence the skull development in highly exposed children. The polymorphism of ALAD and VDR genes might be the molecular inherited factor modifying the susceptibility of lead poisoning. Recently, Chinese government pays more attention to lead pollution and lead poisoning in children problem. The leaded gasoline was prohibited used in motor vehicles since 2000. The government has decided to have a clampdown on the high-polluted lead smelters for recycling the lead from battery in countryside. It is hopeful that the risk of lead poisoning in children will be decreased in the further

• Proceedings of the Korea Association of Crystal Growth Conference
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• 한국결정성장학회 1996년도 The 9th KACG Technical Annual Meeting and the 3rd Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.258-292
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• 1996

In the last year great interest appears to YBCO thin films preparation on different substrate materials. Preparation of epitaxial film is a very difficult problem. There are many requirements to substrate materials that must be fullfilled. Main problems are lattice mismatch (misfit) and similarity of structure. From paper [1] or follows that difference in interatomic distances and angles of substrate and film is mire important problem than similarity of structure. In this work we present interatomic distances and angle relations between substrate materials belonging to ABCO4 group (where A-Sr or Ca, B-rare earth element, C-Al or Ga) of different orientations and YBCO thin films. There are many materials used as substrates for HTsC thin films. ABCO4 group of compounds is characterized by small dielectric constants (it is necessary for microwave applications of HTsC films), absence of twins and small misfit [2]. There most interesting compounds CaNdAlO4, SrLaAlO4 and SrLaGaO4 were investigated. All these compounds are of pseudo-perovskite structure with space group 14/mmm. This structure is very similar to structure of YBCO. SLG substrate has the lowest misfit (0.3%) and dielectric constant. For preparation of then films of substrates of this group of compound plane of <100> orientation are mainly used. Good quality films of <001> orientations are obtained [3]. In this case not only a-a misfit play role, but c-3b misfit is very important too. Sometimes, for preparation of thin films substrates of <001> and <110> orientations were manufactured [3]. Different misfits for different YBCO faces have been analyzed. It has been found that the mismatching factor for (100) face is very similar to that for (001) face so there is possibility of preparation of thin films on both orientations. SrLaAlO4(SLA) and SrLaGaO4(SLG) crystals of general formula ABCO4 have been grown by the Czochralski method. The quality of SLA and SLG crystals strongly depends on axial gradient of temperature and growth and rotation rates. High quality crystals were obtained at axial gradient of temperature near crystal-melt interface lower than 50℃/cm, growth rate 1-3 mm/h and the rotation rate changing from 10-20pm[4]. Strong anisotropy in morphology of SLA and SLG single crystals grown by the Czochralski method is clearly visible. On the basics of our considerations for ABCO4 type of the tetragonal crystals there can appear {001}, {101}, and {110} faces for ionic type model [5]. Morphology of these crystals depend on ionic-covalent character of bonding and crystal growth parameters. Point defects are observed in crystals and they are reflected in color changes (colorless, yellow, green). Point defects are detected in directions perpendicular to oxide planes and are connected with instability of oxygen position in lattice. To investigate facets formations crystals were doped with Cr3+, Er3+, Pr3+, Ba2+. Chromium greater size ion which is substituted for Al3+ clearly induces faceting. There appear easy {110} faces and SLA crystals crack even then the amount of Cr is below 0.3at.% SLG single crystals are not so sensitive to the content of chromium ions. It was also found that if {110} face appears at the beginning of growth process the crystal changes its color on the plane {110} but it happens only on the shoulder part. The projection of {110} face has a great amount of oxygen positions which can be easy defected. Pure and doped SLA and SLG crystals measured by EPR in the<110> direction show more intensive lines than in other directions which allows to suggest that the amount of oxygen defects on the {110} plane is higher. In order to find the origin of colors and their relation with the crystal stability, a set of SLA and SLG crystals were investigated using optical spectroscopy. The colored samples exhibit an absorption band stretching from the UV absorption edge of the crystal, from about 240 nm to about 550 m. In the case of colorless sample, the absorption spectrum consists of a relatively weak band in the UV region. The spectral position and intensities of absorption bands of SLA are typical for imperfection similar to color centers which may be created in most of oxide crystals by UV and X-radiation. It is pointed out that crystal growth process of polycomponent oxide crystals by Czochralski method depends on the preparation of melt and its stoichiometry, orientation of seed, gradient of temperature at crystal-melt interface, parameters of growth (rotation and pulling rate) and control of red-ox atmosphere during seeding and growth (rotation and pulling rate) and control of red-ox atmosphere during seeding and growth. Growth parameters have an influence on the morphology of crystal-melt interface, type and concentration of defects.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제17권8호
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• pp.215-225
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• 2016

This study seeks to find an alternative to the requirement for proving the competitiveness of Korean performing arts before entering into the overseas market by deriving the factors causing entry into the market to be delayed based on an analysis of the current status. Between 2007 to 2014, the overseas revenues from Korean performing arts increased by 16.4% compared to the total amount of financial support, as the number of free performances given overseas and the average guaranteed number of performances overseas are both at a standstill. Also, the size of the audience increased by a mere 3.3 times, which is an even lower growth rate than that for the number of performances, 3.8 times, during the same period. Furthermore, the audience size per unit is suffering from long-term stagnation. The main causes are as follows: 1) applying one-dimensional methods to performing arts exchanges and expanding the overseas market, 2) the existing confused concepts between profit and non-profit contents, 3) the weaknesses of the market expansion strategy, because of programming practices focusing on providers, such as presenters and producers, rather than consumers. As a result, the necessary basic research, including consumer surveys, has not been done yet. In order to understand the implications of this analysis and solve the problem of the delayed overseas expansion of Korean performing arts, the Korean wave industry was examined as a representative example. Consumer surveys for the performing arts, possibly benchmarked to the "Korean Wave Consumer Survey Index (KWCSI)", are expected to be done in the near future. In addition, through the development of a specific consumer index of the performing arts, customized marketing strategies by continent and country need to be established. This empirical study of the overseas expansion of performing arts can be utilized as a bridge between the academic and real worlds. This work may also enable a variety of strategies to be established for the overseas expansion of the performing arts.

• Journal of Korean Society of Environmental Engineers
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• 제27권8호
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• pp.844-851
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• 2005

The purpose of this study was to determine feasibility of application of regenerated or recycled $TiO_2$ on the successive treatment of Cu(II)-EDTA. The recovery of copper, the reuse of $TiO_2$ and the assessment of acute toxicity was studied in the total eight successive photocatalytic reactions. Aqueous solution of $10^{-4}\;M$ Cu(II)-EDTA was treated using an illuminated $TiO_2$ at pH 6 in a circulating reactor. Two different procedures were applied in the reuse of $TiO_2$: i) recycle of $TiO_2$ without acid wash ii) regeneration of $TiO_2$ with acid wash to remove adsorbed copper in a previous experiment. The averaged decomplexation rate constant($k'_{obs}$) of Cu(II)-EDTA in recycle of $TiO_2$ without acid wash was approximately 45% less than that in regeneration of $TiO_2$ with acid wash. Removal of Cu(II) was near complete after 180 minutes in the total eight successive photocatalytic reactions using the regenerated $TiO_2$ after acid wash. In contrast, removal of Cu(II) was minimum at total fifth successive photocatalytic oxidation using the recycled $TiO_2$ without arid wash. The recovered $TiO_2$ was approximately 86% in average in each procedure. The recovered Cu(II) was 67.9% in average. The acute relative toxicity of the treated water rapidly declined at an initial reaction time up to 60 minutes but little declination was observed after 60 minutes due to little degradation of DOC. Relative toxicity of treated water using the recycled $TiO_2$ without acid wash we some what well correlated with the concentration of dissolved Cu(II). From this work, it is suggested that Cu(II)-EDTA can be effectively treated using an integrated cyclic photocatalytic oxidation with recovery of $TiO_2$ and Cu(II).

• Journal of Sericultural and Entomological Science
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• 제8권
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• pp.41-50
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• 1968

In order to achieve efficiency of laying eggs of silkworms, it is very important to eliminate noncocooning silkworms. This study is written on the basis of observation and analysis of mechanism of silkworms physiologically and anatomically. It is hoped that given herein will contribute to the effecting elimination work. Outline of the study summarize as follows: 1. It is observed through microscope that the silkworms which are seen normal state in the silk gland but no ability of cocoon making have polyhedrosis in the nerve, trachea and muscle near the tissue of the spinneret. 2. Relatively high proportion of non-cocooning silkworms are caused by the grasserie of the silkworms. 3. As a result of inoculation with purulent discharges against silkworms from first fooding through 8th day of 5th instar, number of cocooning silkworms were increased when inoculation are applied at laterer day of the instar. In the case of non-cocooning silkworms, meanwhile, resulted not big varriation when it is apllied in the early and middle of the period, but number of non-cocooning silkworm was reduced when the inoculation are given at laterer of the instar. Number of death during rearing and mounting are increased when earliest application of inoculation are carried out. 4. Symptom of grasserie was appeared more or less three days after application of the inoculation. Some silkworms which were inoculated just before mounting has ability of cocooning making even taken grasserie, in this case the silkworm can make thin cocoon. since the silkworm fall sick during cocoon making and unable of spinning soon. when the worm was affected by grasserie slightly, it was observed that the silkworm can spinning. It is supposed to be the light paralysis of spinneret is not very much influenced to spinning. 5. As a result of observation of original stock and hybrid including other 44 kinds of silkworm, many non-cocooning silkworms were found in the original stock especially originated from japanese than in hybrid. 6. A number of undulations are found in the middle division of the silk gland of non-cocooning silkworms. 7. According to the observation of the sizes of the body and digestive organs, normal natured silkworms and non-cocooning silkworms are more or less same in length, but the width, circumference of bodies and digestive organs were more larger in the later. If silkworm which was in the period of active eating of 5th instar was given shock of dropping to the floor, the silkworm receives little more shock when hit to side of the body than to head, and concrete floor than ondol and wooden floor.