• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.1
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• pp.25-30
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• 1987

There are differences in opinion as to whether nitrogen fertilizer should be used when establishing alfalfa (Medicago sativa L.). Various reports show that under a hot environment, rhizobia (Rhizobium meliloti) are not as effective in fixing atmospheric nitrogen as they are under moderate temperatures. It is also believed that the addition of nitrogen fertilizer inhibits nodulation of alfalfa seedlings. A replicated experiment was conducted under controlled environmental conditions at the University of Nevada-Reno, Reno, Nevada, USA, to determine the effects of nitrogen application on seedling growth and nodulation of alfalfa grown in a hot environment. Sterile sand was used as the growing media to which a complete nutrient solution minus nitrogen was applied volumetrically to each pot daily. In addition, half of the pots received NH4-$NO_3$, at the rate of 11.2 kg per ha at seeding and at two and four weeks after planting giving a total nitrogen application rate of 33.6 kg per ha during the seven-week experimental period. Rhizobia inoculant (R-12) consisted of a mixture of strains 171-15a, 1682c and 80 PI 265 of (Rhizobium meliloti). Inoculant was applied to the seeds prior to planting and to the sand media at two and four weeks after seeding. Twenty seeds were planted in pots 14.0 cm in diameter and 11.5 cm deep. Plants were thinned to ten plants per pot after emergence and were grown in a controlled environment chamber with a 16-hour light period. Soil temperature at 6 cm depth ranged from 17.4^{\circ}C.$ to 31.1^{\circ}C.$ and had a daily mean of 26.5^{\circ}C.$. Plants were harvested at weekly intervals for seven weeks. Root, shoot and total length, dry weight, volume and number of nodules per plant were determined. Root, shoot, and total length were greater in seedlings grown in soil where nigrogen was applied than that grown in soil to which no nitrogen was applied. The average size of the seedlings as determined by volume and weight was more than two times greater where plants were fertilized with nitrogen. Nodule number per seedling was also greater when nitrogen was applied compared to those which received no nitrogen. The differences were greater as the plants became older. The rhizobia did not fix enough nitrogen for adequate growth of seedlings. This is probably due to high temperature growing conditions that caused the rhizobia to become relatively ineffective as compared to cooler growing conditions. Data suggests it would be desirable to apply nitrogen at seeding when alfalfa is established under hot conditions that occur in mid- or late summer.

• Korean Journal of Agricultural and Forest Meteorology
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• v.10 no.1
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• pp.25-31
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• 2008

Information on daily maximum air temperature is important in predicting the status of plants and insects, but the uneven and sparse distribution of weather stations prohibits timely access to the data in regions with complex topography. Since cumulative solar irradiance plays a critical role in determining daily maximum temperature on any sloping surfaces, derivation of a quantitative relationship between cumulative solar irradiance and the resultant daily maximum temperature is a prerequisite to development of such estimation models. Air temperatures at 8 sideslope locations with similar elevation and slope angle but aspect, circumventing a cone-shaped, grass-covered parasitic volcano (c.a., 570 m diameter for the bottom circle and 90m bottom-to-top height), were measured from June to December in 2007. Daily maximum temperatures from each location were compared with the average of 8 locations (assumed to be the temperature measured at a "horizontal reference" position). The temperature deviation at all locations increased with the day of year (or sun elevation) from summer solstice to winter solstice. Averaged over the entire period, the south facing location was warmer by $1^{\circ}C$ in daily maximum temperature than "horizontal reference" and the north facing location was cooler by $0.8^{\circ}C$ than the reference, resulting in the year round average south-north temperature difference of $1.8^{\circ}C$. In November, both south and north facing slopes showed the greatest deviation of $+2.0^{\circ}C$ and $-1.3^{\circ}C$, respectively in daily maximum temperature at monthly scale. On a daily scale, the greatest deviation was +3.8 and $2.7^{\circ}C$ at the south and north slope, respectively. The cumulative solar irradiance (on the slope for 4 hours from 11:00 to 15:00 TST) explained >60% of the variance in daily maximum temperature deviations among 8 locations, suggesting a feasibility of developing an estimation model for daily maximum temperature over complex topography at landscape scales.

• Economic and Environmental Geology
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• v.31 no.5
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• pp.389-398
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• 1998

The Au-Ag deposit of the Oknam mine occurs as gold-silver-bearing rhodochrosite veins in biotite schist and phyllite of the Precambriam Yulri Group. Five stages of ore deposition are recognized, each showing a definite mineral assemblage. General mineral parageneses in veins (stage III) associated with gold and silver vary inwardly from the vein margin: arsenopyrite + pyrite $\Rightarrow$ sphalerite+chalcopyrite+galena+gold $\Rightarrow$ ga1ena+Ag-bearing minerals. Fluid inclusion data indicate that temperature and salinity of ore fluids overally decreased with time: $345^{\circ}{\sim}240^{\circ}C$ and 3.4~7.8 wt. % NaCl equiv during stage I (quartz vein mineralization), $313^{\circ}{\sim}207^{\circ}C$ and 2.3~8.7 wt.% NaCl equiv during manganese-bearing carbonate stages (II and III), and $328^{\circ}{\sim}213^{\circ}C$ and 3.6-5.4 wt.% NaCl equiv during stage IV (quartz vein mineralization). The ore fluids probably evolved through repeated pulses of boiling and later mixing with cooler and more dilute meteoric waters. Fluid inclusion data and geologic arguments indicate that pressures during the mineralization were in the range of 90 to 340 bars. Gold occurs as silver-rich electrums (21 to 29 atom. % Au) and was deposited at temperatures between $300^{\circ}$ and $240^{\circ}C$. Thermochemical calculations suggest that gold was deposited as a combined result of increase in pH and decreases in temperature, $fs_2$ and $fo_2$.

• Economic and Environmental Geology
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• v.26 no.2
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• pp.117-127
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• 1993

Ag-Au vein ores from the Weolyu mine, Youngdong district, contain significant germanium (up to 145g/t, average 34.9g/t), in the form of argyrodite ($Ag_8GeS_6$). Mineral chemistries of argyrodite and its associated minerals were determined by electron probe microanalysis. Twenty eight elements in thirteen ore samples were analyzed using an ICP mass spectrometer. Argyrodite occurs in the paragenetically later mineral assemblage consisting of carbonates+quartz+native silver+argentite+Ag-sulfosalts, indicating that the germanium mineralization represents the culmination of a complex mineral sequence which includes early gold and late silver deposition. The mean formula of the argyrodite is $Ag_{7.90}\;(Ge_{0.76}Sn_{0.04})S_6$, with minor amounts of Cu, Fe, Sb, As, Sn, and Zn. The Weolyu argyrodite shows systematic substitutions of Ag by Cu, and of Ge by Sb. Chemical analyses of vein ores indicate that metals were precipitated in the order of $Fe{\rightarrow}Pb$, $Zn{\rightarrow}Cu{\rightarrow}Ag$, Sb, As, Ge. Germanium has a strong geochemical affmity with As and Sb, and Cu, Pb, Zn, Mo, and Sr show weak positive correlations with Ge. Germanium deposition at Weolyu was mainly a result of cooling of hydrothermal fluids (down to $175^{\circ}C{\sim}210^{\circ}C$, due to increasing involvement of cooler meteoric waters in the epithermal system.

• Journal of the Korean Geographical Society
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• v.44 no.4
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• pp.447-462
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• 2009

Kohyun River basin is located at southern parts of Taebaek Mountains and most of river basins consists of sedimentary rock. The aims of this study are to investigate the distribution characteristics and processes of fluvial terraces at Kohyun River, using scientific methods such as classification of fluvial landforms, analysis of geomorphological deposits, XRD and OSL age dating. In Kohyun River basin are three levels terraces from T1 to T3. Fluvial terraces are assumed to be erosional terraces according to deposited situation of alurium and existences of bedrock riverbed. From the result of OSL age dating, formation age of fluvial terrace 1(T1) is calculated about 37,000 yr.B.P.(MIS 3), and fluvial terrace 2(T2) is calculated about 113,000 yr.B.P.(MIS 5). Therefore, fluvial terraces at Kohyun River are assumed to be formed at warmer period in the glacial stages or cooler period in the interglacial stages. The incision rate of fluvial terrace 1 at Kohyun River is calculated to be 0.054m/ka, and the incision rate of fluvial terrace 2 is calculated to be 0.115m/ka. This results suggest to lower incision rate than other rivers in Korea because of low uplift rates and little discharge.

• Publications of The Korean Astronomical Society
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• v.24 no.1
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• pp.53-64
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• 2009

MIRIS is the main payload of the STSAT-3 (Science and Technology Satellite 3) and the first infrared space telescope for astronomical observation in Korea. MIRIS space observation camera (SOC) covers the observation wavelength from $0.9{\mu}m$ to $2.0{\mu}m$ with a wide field of view $3.67^{\circ}\times3.67^{\circ}$. The PICNIC HgCdTe detector in a cold box is cooled down below 100K by a micro Stirling cooler of which cooling capacity is 220mW at 77K. MIRIS SOC adopts passive cooling technique to chill the telescope below 200 K by pointing to the deep space (3K). The cooling mechanism employs a radiator, a Winston cone baffle, a thermal shield, MLI (Multi Layer Insulation) of 30 layers, and GFRP (Glass Fiber Reinforced Plastic) pipe support in the system. Optomechanical analysis was made in order to estimate and compensate possible stresses from the thermal contraction of mounting parts at cryogenic temperatures. Finite Element Analysis (FEA) of mechanical structure was also conducted to ensure safety and stability in launching environments and in orbit. MIRIS SOC will mainly perform Galactic plane survey with narrow band filters (Pa $\alpha$ and Pa $\alpha$ continuum) and CIB (Cosmic Infrared Background) observation with wide band filters (I and H) driven by a cryogenic stepping motor.

• Korean Journal of Environment and Ecology
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• v.29 no.4
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• pp.590-598
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• 2015

Despite various control methods for pine wilt disease, the disease has been increasing at an alarming rate every year in Korea. Still there is a lack of research on the problems of the current methods used to curb the disease. One main method to control pine wilt disease is fumigation for eliminating the larva of the pine sawyer beetle (Monochamus alternatus) which is known as the vector insect for pine wilt disease. We surveyed and analyzed the amount of destroyed uninfected trees in the fumigated area by studying 32 survey plots ($100m^2$) in Miryang city. The destroyed trees' crown area was estimated by induced regression between root collar area and crown area of the remaining trees (coniferous tree: $R^2=57.4$, deciduous broad-leaved tree: $R^2=63.8$). According to the analysis results, the infected trees (cut trees) were 18.7% and cut trees which were not infected were 35.5% of the total tree population of the study area on the basis of total crown area. In case of pine trees, 8.4% of uninfected trees were cut off but 62% of uninfected deciduous broad-leaved trees including Quercus spp. were affected and damaged during the fumigation process. Since these broad-leaved trees dominate the sub-canopy layer of the forest, this indiscriminate interruption of broad-leaved trees has the adverse effect of depriving the public benefits such as shadow, a cooler weather, controlling humidity, etc.

• Korean Journal of Optics and Photonics
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• v.16 no.3
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• pp.209-216
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• 2005

A new second generation advanced thermal imager, which can be used for battle tank sight has been developed by ADD. This system uses a $480\times6$ TDI HgCdTe detector, operating in the $7.7-10.3{\mu}m$ wavelength made by Sofradir. The IR optics has dual field of views such as $2.67\times2^{\circ}$ in NFOV and $10\times7.5^{\circ}$ in WFOV. And also, this optics is used for athermalization of the system. It is certain that our sensor can be used in wide temperature range without any degradation of the system performance. The scanning system to be able to display 470,000 pixels is developed so that the pixel number is greatly increased comparing with the first generation thermal imaging system. In order to correct non-uniformity of detector arrays, the two point correction method has been developed by using the thermo electric cooler. Additionally, to enhance the image of low contrast and improve the detection capability, we have proposed the new technique of histogram processing being suitable for the characteristics of contrast distribution of thermal imagery. Through these image processing techniques, we obtained the highest quality thermal image. The MRTD of the LWIR thermal sight shows good results below 0.05K at spatial frequency 2 cycles/mrad at the narrow field of view.

• Korean Journal of Human Ecology
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• v.10 no.4
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• pp.399-409
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• 2001

The purpose of this study was to evaluate the preference of image for modern application of Korean traditional patterns. A survey was conducted using the random selection among female undergraduate students in Daegu city. The degree of interest and preference in Korean traditional style or something like that measured by 5 scale method. And then they were classified into two groups which were interest/non-interest group, and preference/non-preference group. The image of Korean traditional patterns consisted of semantic differential scales. Frequency, percentage and mean were analyzed, for difference of groups t-test was analyzed. The results were as fellows; 1. For the degree of interest for Korean traditional patterns, it was showed that 53.8% of total respondents took interest and about 40.4% of them had preference for traditional patterns. the correlation coefficient of the degree of interest and preference was 0.782(p<0.01) and showed that the positive correlation was high. 2. Among 20 kinds of Korean traditional patterns, the degree of preference for the patterns of plants and nature was quite high whereas that for the patterns of geometrical things was low relatively. 3. It was evaluated that pattern of nature was fresh, refined and womanly image generally. It was evaluated that pattern of plants was womanly, fresh, weak, light and soft image and that of animals was heavy, splendid, high-class, manly, strong and positive image. It was evaluated that pattern of geometrical things was the most refined image and high-class, rigid and strong. 4. The statistical significance of mean between interest/non-interest group was showed statistically in the patterns of clouds, mountains, lotus, apricot, orchid, dragon, phoenix and bogey. In case of pattern of orchids, the degree of preference was most different between interest/non-interest group. 5. The pattern of plants showed the most different evaluation for images between interest/non-interest group. For refined/old-fashioned polar adjective images, the interest group evaluated the pattern of plants more refined. 6. For pattern of orchids, the difference of degree of preference between preference/non-preference group was most remarkable in Korean traditional patterns. 7. The pattern of geometrical things showed the most different evaluation for images between preference/non-preference group. For warm/cool polar adjective images, the preference group evaluated the pattern of geometrical things cooler.

• The Korean Journal of Quaternary Research
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• v.11 no.1
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• pp.57-68
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• 1997

Climatic change of the late-Quaternary period has been record-ed in the loess deposits of the central Great plains and the record of such change is extractable using a number of approaches and parameters. The stratigraphy of loess deposits which have been investigated on Fort Riley exhibits the same sequence of loess units and intercalated buried soils as is found elsewhere in the re-gion but adds detail unique to the reservation Upland late-Qua-ternary composite stratigraphy preserved on the reservation con-sists of the basal Sangamon soil of the Last interglacial(c. 120-110ka), Gilman Canyon Formation(c. >40 -20ka), Peoria loess(c. 20 -10ka) Brady soil(c. 11 -10ka) Bignell loess(c. 9-\ulcornerka). and mod-ern surface soil. Application of magnetic analyses has provided proxy data sets that represent a time series of climatically regulated pedogenesis/weathering and botanical composition. magetic data have yielded an impression of the variation in climate from Sangamon time to the late Holocene through a reconstruction of the history of pedogenesis/weathering. Sangamon soil formation dominated the reservation durin the Last interglacial as indicated by magnetic parameters. During Gil-man Canyon time loess influx was usually sufficiently slow as to permit pedogenesis which appears to have been at a maximum twice during that time. Warm season grasses were important dur-ing soil formation but diminished in importance during the peri-ods of more rapid loess fall which were cooler and perhaps wet-ter. Peoria loess fall a function of the deterioration of climate during the last Glacial Maximum thinly blanketed the reservation with thickest accumulations occurring to the north-west(Bala Cemetery site)proximal to the source region. Long-term surface stability did not apparently occur within Peoria time but short-term stability may be indicaed by the presence of thin weathering zones(incipient soils) in the Peoria loess. Re-gional landscape stability prevailed during the environmental shift at the Pleistocene/Holocene transition resulting in forma-tion of the well expressed Brady soil. One or more weak soils developed in the Bignell loess as it ac-cumulated. A notable feature of the Bignell loess is the appear-ance of the Altithermal dry period: the loess experienced little weathering and was dominated by warm season grasses until the latter of the Holocene.