• Tunnel and Underground Space
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• v.20 no.4
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• pp.241-251
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• 2010

The polar region is in the limelight for an academic worth as well as plenty of natural resources. The study on the polar region was reviewed for better understanding of the polar region and its rock properties. The antarctica has a windy and dry climate along with the lowest temperature on the earth. The thermal distribution according to depth in the area was reported: The freezing-thawing process was repeated in shallow depth, and the temperature falls down below zero under the specific depth. There is a great temperature difference between the atmosphere and rock. A research reported for the degree of weathering of the antarctic slope by using Schmidt hammer and Taffoni test. The rock specimens weathered by repeated freezing-thawing process were tested of the shore hardness and uniaxial compressive strength: The rock strength gradually decreased as the freezing-thawing process was repeated. The comprehensive mechanical properties of the polar region rocks and the relationship between the laboratory weathering test result and the real rock property change in the site remain as future research topics.

• Journal of Korean Neurosurgical Society
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• v.64 no.6
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• pp.901-912
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• 2021

Objective : In the cervical spine, many surgical procedures have been developed to achieve optimal results for various disorders, including degenerative diseases, traumatic injury, and tumor. In this study, we report our experience and follow-up results with a new surgical technique for cervical spine entitled posterior floating laminotomy (PFL) in comparison with conventional laminectomy and fusion (LF). Methods : Data for 85 patients who underwent conventional LF (n=66) or PFL (n=19) for cervical spine disorders between 2012 and 2019 were analyzed. Radiological parameters, including cervical lordosis (CL), T1 slope (T1S), segmental lordosis (SL), and C2-7 sagittal vertical axis (SVA), were measured with lateral spine X-rays. Functional outcomes, comprising the modified Japanese Orthopaedic Association (mJOA), neck disability index (NDI), and visual analog scale (VAS) scores, were also measured. For the patients who underwent PFL, postoperative magnetic resonance image (MRI) was performed in a month after the surgery, and the degree of decompression was evaluated at the T2-weighted axial image, and postoperative computed tomography (CT) was conducted immediately and 1 year after the operation to evaluate the gutter fusion. Results : There was no difference in CL, T1S, SL, and C2-7 SVA between the groups but there was a difference in the preoperative and postoperative SL angles. The mean difference in the preoperative SL angle compared with that at the last follow-up was -0.3° after conventional LF and 4.7° after PFL (p=0.04), respectively. mJOA, NDI, and VAS scores showed significant improvements (p<0.05) during follow-up in both groups. In the PFL group, postoperative MRI showed sufficient decompression and postoperative CT revealed gutter fusion at 1 year after the operation. Conclusion : PFL is a safe surgical method which can preserve postoperative CL and achieve good clinical outcomes.

• Journal of the Korean GEO-environmental Society
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• v.12 no.8
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• pp.5-12
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• 2011

This study was performed to analyze the degree of rainfalls, the duration time of rainfalls, the inclination of slopes and other damage causes depending on the ground condition, when the landslide occurs by the rainfall. Based on that, a big and a small model soil box were compared to examine the features of landslides, which is ultimately for forecasting landslides. An artificial rainfall device was installed in the model box, and the large model box has a real-size slope in it. Also, various measures were fulfilled such as collapse forms, a pore pressure, an earth pressure and moisture contents in order to analyze the effect of the model box size on the landslide mechanism and to test the usability of a small model box as a material for landslide experiments.

• Journal of the Korean Institute of Telematics and Electronics
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• v.16 no.4
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• pp.36-46
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• 1979

Using N_ Ch silicon gate technology . the capacitors and transistors with various dimenssion were fabricated. Although the applied process was somewhat standard the conditions of ion implantation for the gate were varied by changing the implant energies from 30keV to 60keV for B and from 100 keV to 175keV for P . The doses of the implant also changed from 3 $\times$ 10 /$\textrm{cm}^2$ to 5 $\times$ 10 /$\textrm{cm}^2$ for B and from 4$\times$ 10 /$\textrm{cm}^2$ to 7 $\times$ 10 /$\textrm{cm}^2$ for P . The D. C. parameters such as threshold voltage. substrate doping level, the degree of inversion, capacitance. flat band voltage, depletion layer width, gate oxide thickless, surface states, motile charge density, electron mobility. leakage current were evaluated and also compared with the corresponing theoretical values and / or good numbers for application. The threshold voltages measured using curve tracer and C-V plot gave good agreements with the values calculated from SUPREM II which has been developed by Stanford University process group. The threshold vol tapes with back gate bias were used to calculate the change of the substrate doping level. The measured subthreshold slope enabled the prediction of the degree of inversion The D. C. testing results suggest the realized capacitors and transistors are suited for the memory applications.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.6
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• pp.341-348
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• 2003

Mechanical stimuli to the cardiac myocytes initiate many biochemical and physiological events. Stretch-activated cation channels have been suggested to mediate these events. In this study, cell-attached and inside-out excised-patch clamp methods were used to identify stretch-activated cation channels in adult rat atrial myocytes. Channel openings were increased in cell-attached configuration when negative pressure was applied to the pipette, and also in inside-out excised patches by negative pressure. The channel was not permeable to $Cl^-$, $Na^+$ and $Cs^+$, but selectively permeable to $K^+$, and the degree of activation was dependent on the magnitude of negative pressure (full activation at ${\sim} -50 mmHg). In symmetrical 140 mM KCl, the slope conductance was $51.2{\pm}3$ pS between the potentials of -80 and 0 mV and $55{\pm}6$ pS between 0 and +80 mV (n=5). Glibenclamide ($100{mu}M$) or ATP (2 mM) failed to block the channel openings, indicating that it is not ATP-sensitive $K^+$ channel. Arachidonic acid ($30{mu}M$), which has been shown to activate a $K^+$ channel cooperatively with membrane stretch, did not affect the channel activity. $GdCl_3$ ($100{mu}M$) also did not alter the activity. These results demonstrate that the mechanical stretch in rat atrial myocytes activates a novel $K^+$-selective cation channel, which is not associated with other $K^+$ channels such as ATP-sensitive and arachidonic acid-activated $K^+$ channel.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.246-255
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• 2011

This study was carried out to investigate the characteristics of wind damaged trees in the Hongneung Arboretumin Korea. Many trees in the Hongneung Arboretum were damaged by the 'Kompasu', the seventh typhoon in the year of 2010 having strong impacts on the central region of Korea. Damaged trees were divided into 3 damage types: windthrow, slanted and broken trees. Most of damaged trees (97.3%) were found at low slope (below 15 degree) or medium slope (15~20 degree). The 45.3% of damaged trees were coniferous and 54.7% were deciduous trees. The wind speed was recorded for the duration of the typhoon from 04:00 AM to 12:00 PM on September 2. The average wind speed and the maximum instantaneous wind speed inside the forest were 1.4 m/sec and 3.5 m/sec, respectively. The highest peak of the average and the maximum instantaneous wind speed inside of forest, 3.4 m/sec and 8.7 m/sec respectively, were recorded at 06:10 AM on September 2. To analyze relationship between wind characteristics and the damage types, the average wind speed and the frequency of wind wave was compared to those of pre-typhoon period (Feb. 13, Feb. 20, Apr. 21, Oct. 16, 2009 and Mar. 20, 2010). The results indicated that the damaged trees were affected by frequent wind wave rather than the wind speed itself. Also average wind direction inside the forest was analyzed to investigate the impact of wind direction on the damaged trees. The wind had mainly blown from SE and SW, and the maximum instantaneous wind direction was SE direction overall. Most of the damaged trees (84.0%) had fallen down to the NW or NE direction. This result showed that the fallen direction of the damaged trees and wind direction was highly related. Therefore, we found that the frequency of wind wave was the main factor of wind damages during the typhoon 'Kompasu' and wind direction was highly related to the fallen direction.

• Journal of Sericultural and Entomological Science
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• v.17 no.2
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• pp.141-149
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• 1975

Silkworm is known to be damaged under the unfavorable environmental conditions. Recently, it has been often argued that nicotine is a main factor to affect the silkworm nutritional balance and to result in decrease of quantitative characters, and unbalance of larval nutrition. Especially in spring season, there is tendency to produce nicotine damage to silkworm fed with the mulberry leaf near to tobacco field early cultivated in mulching system. In these connections, the trial was made in the different pots placing by the different distance 10rn, 20m, 40m, and 60m in the direction of east-north from the tobacco field. Location of pot near to the tobacco fold is 40m below the tobacco Held and gradually higher than the tobacco field by 10 degree of slope. In addition, when the mulberry field is divided into two areas from the east-south to west-north, southern east zone is lowering down below 10 degree of slope and has 36％ of east-south wind, 21％ of south-east wind and 16％ of south wind, etc. Pots are left on the mulberry field from the completion of lower part leaf harvest to just before upper part leaf harvest is completed for 32 days. Then silkworm at 4th-5th stage was fed with the leaf grown during the period and larval characters are statistically analyzed. The results are summarized as follows： 1. 10-40m distant pot statistically at the same level has the longest larval duration and 60m distant pot is. not significant at 5％ level. Whole larval duration has same tendency as in the 5th larval duration. 2. Percentage of delayed molting larvae at the 5th stage is increased in 10m distant pot and there is no significance statistically in other pots, as compared with that of control. 3. It is not showed that there is no damage to mortality of the old larvae in 60m distant pot. 4. 10-20m distant pot produces a low pupation and others are at the same level statistically at 5％ significance, 5. It is showed that nicotine damage is occurred in single cocoon freight and cocoon shell weight up to 60m distant pot, rather higher damage in cocoon shell weight than in single cocoon weight. 6. It is showed that cocoon yield from 10, 000 molted larvae including double cocoon is decreased up to 40m distant pot far from the tobacco field in which 40％ of cocoon yield in 10m distant pot by 7kg, 26％ of cocoon yield in 20m distant pot by 3.9kg, 24％ of cocoon yield in 40m distant pot by 3.6kg, and 12％ of cocoon yield in 60m distant pot by 1.8kg, as compared with control. However, there is no significance statistically at 5％ level in 60m distant pot. With these above results, it is concluded that nicotine da mage could be occurred in cocoon yield and cocoon quality up to 60m distant far from the tobacco field.

• Korean Journal of Ecology and Environment
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• v.49 no.2
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• pp.102-109
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• 2016

The sustainability of Iris koreana, a rare and endemic plant designated by the Korea Forest Service, is threatened due to artificial factors such as habitats loss and climate change etc. and internal factors such as changes in biological properties of the habitats etc. but conservation biology research has not been performed in South Korea. The objective of this study is to establish the species conservation strategies by analyzing the characteristics of their habitats, including: 1) Population characteristics, and 2) habitat analysis of the vegetation and abiotic environments. From April to May, 2015, population characteristics [density (stems $m^{-2}$), flowering rate (%) and leaf area size ($cm^2$)] in I. koreana habitats such as Buan1~6 (BA1~6), Jangseong1~2 (JS1~2) and vegetation characteristics (phytosociological research and ordination analysis), and abiotic environments [soil temperature ($^{\circ}C$), soil humidity (%), transmitted light ($mol{\cdot}m^{-2}{\cdot}d^{-1}$) and canopy openness (%)] were measured. I. koreana was mainly distributed at elevation 50 to 150 m and 2 to $11^{\circ}$ slope. Slope direction was shown as 90 to $193^{\circ}$. The average degree of canopy openness was 11.9%. It showed the highest at BA2 (17.5) and the lowest at JS1 (7.7). The average degree of transmitted light was $6.3mol{\cdot}m^{-2}{\cdot}d^{-1}$. It showed the highest at BA2 (10.1) and the lowest at JS1 (3.6). Population density showed average 25.8 (stems $m^{-2}$). It showed the highest at JS2 (19.7) and the lowest at JS1 (9.3). flowering stems showed average 16.9 (stems). It showed the highest at BA3 (35) and the lowest at BA5 (4). Leaf area size was average $94.1cm^2$.

• Korean Journal of Ecology and Environment
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• v.48 no.4
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• pp.253-262
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• 2015

The sustainability of Cypripedium japonicum, a rare plant designated by the Korea Forest Service, is threatened due to artificial factors such as habitat loss and climate change etc. and internal factors such as changes in biological properties of the habitat etc. but conservation research has not been performed in South Korea. The objective of this study is to establish the species conservation strategies by analyzing the characteristics of their habitats, including: 1) Population characteristics, and 2) habitat analysis of the vegetation and abiotic environments. From April to September, 2014, population characteristics [density (stems $m^{-2}$), flowering rate (%), and leaf area ($cm^2$)] in Cypripedium japonicum habitats such as Chuncheon (CC), Hwacheon (HC), Muju (MJ), and Gwangyang (GY) and vegetation characteristics (plant sociological research and ordination analysis), and abiotic environments [temperature ($^{\circ}C$), relative humidity (%), transmitted light ($mol{\cdot}m^{-2}{\cdot}d^{-1}$) and canopy openness (%)] were measured. Cypripedium japonicum was mainly distributed at elevation 450 to 990 m and 5 to $30^{\circ}$ slope. Slope direction was shown as 0 to $110^{\circ}$. Habitats temperature (mean $18.94^{\circ}C$) was well matched to seasonal changes. Differences among sites showed greater level according to latitude difference. It showed the highest in habitat, GY located in the South. On the other hand, relative humidity (77.38%) didn't show much difference among sites. The average degree of canopy openness was 18.17%. It showed the highest at HC (22.1%) and the lowest at MJ (16.1%). The average degree of transmitted light was $9.1mol{\cdot}m^{-2}{\cdot}d^{-1}$. It showed the highest at CC ($10.6mol{\cdot}m^{-2}{\cdot}d^{-1}$) and the lowest at GY ($6.87mol{\cdot}m^{-2}{\cdot}d^{-1}$). Chlorophyll content showed average 26.12 SPAD. It showed the highest at MJ (30.64 SPAD value) and the lowest at HC (23.69 SPAD value). Leaf area was average $253.35cm^2$. It showed the highest at CC ($281.51cm^2$) and the lowest at HC ($238.23cm^2$).

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.6
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• pp.357-365
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• 2006

The investigations were conducted to find out the situation of fertilizer use and the contents of soil chemical components on summer vegetable crops at 791 farmers' upland fields located in the parts of Gangwon-do, Gyengsangbuk-do and Jeollabuk-do of alpine area. Major vegetable crops were potato, Chinese cabbage, radish, carrot, onion, and cabbage. From the location surroundings cultivated alpine vegetable crops, the orders were Gangwon-do>Gyeongsangbuk-do>Jeollabuk-do part in the sizes of a fie1d area and the height above sea level, and Jeollabuk-do>Gyeongsangbuk-do>Gangwon-do part in the slope degrees. The soil texture was of wide distribution on sandy loam soil for Gangwon-do(76%) and Jeollabuk-do part(64%), and 1oam(42%) and sandy loam soil(35%) for Gyeongsangbuk-do part. From the numbers of investigated fields, the distribution of slope degree was wider than those of height above sea level in relation to location surroundings. The upland soils of 785 fields cultivated vegetable crops were sampled at 0~15 cm of top soil before seeding or transplanting and analyzed. On an average, pH, organic matter, available phosphate and exchangeable potassium, calcium, magnesium of soil were 5.7, $27.6g\;kg^{-1}$, $765mg\;kg^{-1}$, $1.16cmol_c\;kg^{-1}$, $6.1cmol_c\;kg^{-1}$, and $1.6cmol_c\;kg^{-1}$, respectively. The average cation exchange capacity(CEC) of 120 sites in Gangwon-do part was $9.2cmol_c\;kg^{-1}$. The content of organic matter, exchangeable potassium, exchangeable calcium and exchangeable magnesium was higher, while that of available phosphate was lower with slope degrees. And the content of major chemical components in carrot soil was lower in comparison with other crop soils. The average levels of N, $P_2O_5$, $K_2O$, livestock manure and lime fertilizer of 785 Belds applied by farmers were 335, 198, 244, 12,680 and $1,750kg\;ha^{-1}$, respectively, for summer vegetable crops in alpine area. The average amounts of $N-P_2O_5-K_2O$ fertilizers applied by farmers in 785 Gelds of vegetable crops were higher 1.7~2.0-4.2~7.0-1.4~2.0 times on potato, 1.4~1.6-4.6~8.3-3.5~4.2 times on Chinese cabbage, and 1.2~1.3-4.2~7.2-3.0~3.61 times on radish than the rates of NPK fertilizers based on soil testing for each crop.