• Explosives and Blasting
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• v.27 no.2
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• pp.1-11
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• 2009

Abstract By investigating the stress redistribution caused by the preceding cut blasting when applying the pre-splitting method to tunnel round, an attempt was made to find conditions that were favorable for the propagation of cracks in contour holes. The investigation of the direction of minor principal stress in the numerical analysis revealed that the most significant factor affecting the change of the direction was the loading condition, while the core shape, rock type, and tunnel depth seemed to be less important in determining the direction of minor principal stress. Moreover, the number of cracks tended to increase with the increase of deviatoric stress. Through the model test of pre-splitting, it is confirmed that the pre-splitting method taking the stress field into account can reduce the extent of yield zone and has advantage in controlling the direction of crack than the conventional one.

• Tuberculosis and Respiratory Diseases
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• v.70 no.1
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• pp.51-57
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• 2011

Background: Early recognition and treatment of sepsis would improve patients' outcome. But it is difficult to distinguish between sepsis and non-infectious conditions in the acute phase of clinical deterioration. We studied serum level of procalcitonin (PCT) as a method to diagnose and to evaluate sepsis. Methods: Between 1 March 2009 and 30 September 2009, 178 patients had their serum PCT tested during their clinical deterioration in the medical intensive care unit. These laboratories were evaluated, on a retrospective basis. We classified their clinical status as non-infection, local infection, sepsis, severe sepsis, and septic shock. Then, we compared their clinical status with level of PCT. Results: The number of clinical status is as follows: 18 non-infection, 33 local infection, 39 sepsis, 26 severe sepsis, and 62 septic shock patients. PCT level of non-septic group (non-infection and local infection) and septic group (sepsis, severe sepsis, septic shock) was $0.36{\pm}0.57$ ng/mL and $18.09{\pm}36.53$ ng/mL (p<0.001), respectively. Area under the curve for diagnosis of sepsis using cut-off value of PCT >0.5 ng/mL was 0.841 (p<0.001). Level of PCT as clinical status was statistically different between severe sepsis and septic shock ($^*severe$ sepsis; $4.53{\pm}6.15$ ng/mL, $^*septic$ shock $34.26{\pm}47.10$ ng/mL, $^*p$ <0.001). Conclusion: Level of PCT at clinical deterioration showed diagnostic power for septic condition. The level of PCT was statistically different between severe sepsis and septic shock.

• Journal of the Korean Vacuum Society
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• v.18 no.4
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• pp.272-280
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• 2009

In this study is performed to investigate the pumping characteristics of three-stage disk-type molecular drag pump (DTDP). The experiments are measured using five vacuum pressure gauges in the positions for rotors of DTDP. The experimented DTDP is consisted of three rotors and four stator. In the DTDP, spiral channels of three rotors are cut on the both upper surface and lower surface of a rotating disk, and corresponding stator is a planar disk. The experiments are performed in the outlet pressure range of $0.2{\sim}533\;Pa$. The pressure of each rotors are measured under the various condition of outlet pressure and throughputs, and nitrogen gas is used for test gas. In the numerical study, the pumping characteristics of each rotor are studied for the variation of throughputs in the all rotating channel. Pressure contour and velocity are obtained by the numerical simulation.

• Geomechanics and Engineering
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• v.19 no.1
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• pp.1-9
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• 2019

Shallow failures occur frequently in both engineered and natural slopes in expansive soils. Rainfall infiltration is the most predominant triggering factor that contributes to slope failures in both expansive soils and clayey soils. However, slope failures in expansive soils have some distinct characteristics in comparison to slopes in conventional clayey soils. They typically undergo shallow failures with gentle sliding retrogression characteristics. The shallow sliding mass near the slope surface is typically in a state of unsaturated condition and will exhibit significant volume changes with increasing water content during rainfall periods. Many other properties or characteristics change such as the shear strength, matric suction including stress distribution change with respect to depth and time. All these parameters have a significant contribution to the expansive soil slopes instability and are difficult to take into consideration in slope stability analysis using traditional slope stability analysis methods based on principles of saturated soil mechanics. In this paper, commercial software VADOSE/W that can account for climatic factors is used to predict variation of matric suction with respect to time for an expansive soil cut slope in China, which is reported in the literature. The variation of factor of safety with respect to time for this slope is computed using SLOPE/W by taking account of shear strength reduction associated with loss of matric suction extending state-of-the art understanding of the mechanics of unsaturated soils.

• Korean Journal of Exercise Nutrition
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• v.25 no.3
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• pp.16-22
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• 2021

[Purpose] Exercise-associated hyponatremia (EAH) is a well-known condition among endurance athletes at low altitudes. The incidence of EAH during ultramarathons at high altitudes warrants further investigation. This prospective observational study was conducted on the participants of the Leadville Trail 100 run, a 161-km race held at a high altitude (2,800 m-3,840 m). [Methods] Venous blood samples were collected before and immediately after the race. The participants completed an electronic survey after the race. Our main outcome measure was the post-race serum sodium ([Na⁺]) level. [Results] Of the 672 athletes who started the race, 351 (52%) successfully completed the event within the 30-hour cut-off. Post-race blood samples were collected from 84 runners (66 finishers). Both pre- and post-race blood samples were collected from 37 participants. Twenty percent of the post-race participants had EAH. Only one post-race participant had a [Na⁺] level of <130 mmol/L. All participants with EAH were asymptomatic. One participant had an abnormal pre-race [Na⁺] level (134 mmol/L). Female participants had a significantly higher rate of EAH than male participants (40% vs. 16%; p=0.039). Age, body mass index, weight changes, race completion status, nonsteroidal anti-inflammatory drug use, and urine specific gravity were not associated with the development of EAH. Lower postrace [Na⁺] levels were associated with higher serum creatine kinase values (R²=0.1, p<0.005). [Conclusion] High altitude (3,840 m peak) does not appear to enhance the incidence of EAH after an ultramarathon footrace. This suggests that ambient temperature (low temperatures reduce risk), sex (female predilection), endurance running, and overhydration are more prominent risk factors for EAH than high altitude.

• The Journal of Engineering Geology
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• v.26 no.4
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• pp.447-460
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• 2016

Samples of Hangdeung granite and Berea sandstone containing sliding planes were prepared by saw-cutting and polishing using #100 or #600 grinding powders. Their basic friction angles were then measured directly in direct shear tests and triaxial compression tests, and also in tilt tests, which measure the angles indirectly. Although the angles measured by the direct methods were generally accurate, those measured along certain planes were greatly different from the others depending on the condition of the plane. The tilt tests yielded similar angles regardless of the sliding plane condition or the rock type; however, the error range was relatively wide. Sliding planes polished by the grinding powders yielded more accurate results than those cut by the saw and tested without polishing, as polishing ensured consistent conditions among all the planes. Sliding planes polished using #100 grinding powder yielded better results than polishing with #600 grinding powder. Therefore, the basic friction angles measured along the sliding planes polished using #100 grinding powder, as obtained in direct shear and triaxial compression tests, were the most reliable. The angle could also be measured satisfactorily by tilt testing along sliding planes polished with #100 grinding powder.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.3
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• pp.75-84
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• 1992

The paper manufactories in Sangpyeong Industrial Estates, Chinju, produce more than 80 tons of paper-mill sludge cakes every day, which costs about 840 million won for dump per year. Since the paper-mill sludge is biodegradable, the sludge can he utilized as an organic fertilizer if it is properly decomposed. This may lead to not only dramatic cut of the treatment cost but prevention from secondary environmental contamination due to dump. The primary objective of the study was to explore the quantitative range of major enviromental parameters influencing early composting of paper-mill cakes, naturally pretreated in warn and cold weather. The automatically-controlled reactor was designed, manufactured, and operated for nine days to decompose about 2201 of raw sludge cakes. Four tests(Test 1-Test 4) were implemented for the study of Phase I. Treatments of two levels of initial temperature (40˚C and 28˚C) and two levels of water content + C/N ratio (35% + 40 and 63% + 80) were made to test the significance of their parameters for decomposition of raw sludge cakes pretreated in warm weather. Another four tests (Test 5- Test 8) were implemented for the study of Phase II. Treatments of initial temperature and water content(W/C) + C/N ratio of raw sludge pretreated in cold weather were made to 16˚C and 13% +58 for Test 5, 6˚C and 53% +55 for Test 6, 7˚C and 36% +81 for Test 7, 31˚C and 30% +81 for Test 8. Natural weater condition(pretreatment condition) revealed the importance m composting of the paper-mill sludge cakes. Combination of water content adjustment to about 30% with C/N ratio amendment of about 20 and initial temperature of 30~40˚C was concluded to be the best for early composting of paper-mill sludge cakes with aeration rate and pH fixed. Temperature and C/N ratio were adapted as judging variables for composting degree. In addition, tests for microbial activity were performed to validate the experimental results. Since the temperature and C/N ratio did not coincide in some tests as judging variables for the maturity of the composting sludges, taking one of these parameters could mislead the concept of the maturity (composting conceptually new criterion to provide more reliable information for early composting of paper-mill sludge cakes.

• The Journal of the Petrological Society of Korea
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• v.7 no.1
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• pp.53-68
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• 1998

Microstructural and rock structural analyses on the deformed Cheongsan granite characterized by abundant K-feldspar megacrysts have been carried out to understand the temperature condition for the ductile shear deformation. In K-feldspar, microkinks, microfractures and core-and-mantle structures without the development of subgrains in outer core-zone are the most common microstructures observed. Myrmekites and flame perthites are developed at the strain-localized areas along the microfractured K-feldspar. In plagioclase, microfractures, deformation twins and kink bands are predominant. The deformation twins cut across the igneous zonation of the plagioclase. Patterns of c-axis fabrics of dynamically recrystallized new quartz grains display single girdle and type II crossed girdle where prism slip system is predominant. These characteristic microstructures produced during the ductile shearing suggest that the ductile shear deformation in the Cheongsan granite occurred under epidote-amphibolite conditions($400-500^{\circ}C$). Three main shear zones are recognized at outcrop scale: discrete shear zone with anastomosing high-strain domain, shear zone with pervasive S-C structure and shear zone with homogeneously foliated domain. Geometric features of these shear zones produced during the ductile shear deformation are controlled by amount of strain under the $400-500^{\circ}C$ deformation temperature.

• Journal of Korean Society of Forest Science
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• v.98 no.4
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• pp.417-425
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• 2009

This study analyzed core issues addressed in the tentative agreement of WTO ministerial meetings held to finish WTO/DDA negotiations in Geneva in July 2008. The objectives of this study are to analyze changes in tariff reduction on timber products, and their influence on demand and supply of the items according to the modality of Non-Agricultural Market Access (NAMA) and to provide basic information for strategy formulation of our country for further WTO/DDA negotiations. The results indicate that there will not be significant changes in the tariff on sawnwood and on veneer sheets, however, the tariff on plywood need to be cut by around 50% from the applicable tariff rates of 2008 on condition that our country is in the position of developed countries. Therefore, the item of plywood is expected to be influenced greatly according to the change in tariff reduction. From the analysis of influence of tariff reduction on the demand and supply of timber products including sawnwood and wood based panels, such as plywood, particleboard, and fiberboard, the import quantities of the items are expected to be changed from 0.8% to 13.3% if our country is in the position of developed countries, however, they are expected to decline by 0.8%~44.3%, if our country is in the position of developing countries (22, coefficient for developing members).

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.3
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• pp.164-168
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• 1986

This study was conducted at the forage experiment field of SNU, Snweon to investigate effects of sowing time and seeding rate on growth characteristics, winter survival and dry matter yield of forage rye (Secale cereale L.) as fresh-cut forage. Treatments involved 9 combinations of sowing times (September 8, 28 and October 18) and seeding rates(80, 130 and 180kg $ha^{-1}$). Plant height was not influenced by the time of sowing, but forage rye had a tendency to be taller as increasing seeding rate when sown on September 8 and October 28 and harvested in fall and spring, respectively, Winter survival was reduced by fall harvesting in the plot sown on September 8, however, total dry matter yield was increased by the fall harvesting. Average dry matter yields of 5884, 4993 and 3525kg $ha^{-1}$ were obtained when forage rye was sown on September 8, 28 and October 18, respectively. Dry matter yield was decreased as delaying the time of sowing, but a tendency toward higher yield of forage rye by increasing seeding rate was observed. Yield difference by seeding rates was markedly larger when forage rye was sown on October 18 than September 8 and 28. Based on the results of this study, it appears that the dry matter yield of forage rye could be enhanced by sowing early to late September under upland condition in the middle plain are of Korea. The seeding rates of 80 to 130 kg $ha^{-1}$ and 180kg $ha^{-1}$ would be suitable for early to mid fall and late fall sowings, respectively.