• Journal of the Korean Wood Science and Technology
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• v.16 no.2
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• pp.69-78
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• 1988

For the modification of kiln drying schedule, rela ons between drying resistance R and moisture content or drying times were found 2.5cm-and 5.0cm-thick pitch pine (Pinus rigida Mill.) board and dimension lumber by the conventional kiln drying schedule until the average moisture content was 10%. The results of this study were as follows. 1. Drying resistance increased curvilinearly as moisture content decreased, and was higher for dimension lumber than for board at a given moisture content. The relationships between drying resistance and moisture content for the conventional kiln drying schedule and thickness of lumber were 1) $R_{2.5}=6.795\times10^3M^{-1.27^{**}}$ for 2.5cm-thick board by the conventional kiln drying schedule. 3) $R_{5.0}=5.206\times10^4M^{-1.55^{**}}$ for 5.0cm-thick dimension lumber by the conventional kiln drying schedule. 2. As drying time increased, moisture content decreased and drying resistance increased at the same time. Gradient of slope for dimension lumber was gentler than board. 3. The predicted drying times to 10% moisture content with the conventional kiln drying schedule were a little shorter than actual drying times with relatively small error. 4. It is necessary for the conventional kiln drying schedule to be modified to provide the desired final moisture content at minimum drying time with no significant degrade under severe drying conditions. 5. The kiln factors for 2.5cm-thick board and 5.0cm-thick dimension lumber with the conventional kiln drying schedule were 1.112, 1.136, respectively.

• Geophysics and Geophysical Exploration
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• v.18 no.4
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• pp.171-180
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• 2015

Electrical resistivity of 23 core samples from Ulleung Island at dry or saturated condition has been measured along with dry density and effective porosity, and the relations between the properties has also been discussed. Upper and lower bounds of electrical resistivity at room temperature can be provided by the dry- and saturated-resistivity, respectively. Injecting nitrogen gas to the pore space at the very end of drying process can prevent humid air from getting into the pore space, so that measurement of dry-resistivity can be less affected by humidity in the air. Dry density and porosity have very close correlation; the ratio between increase of porosity and the decrease of density showed distinct relation to the rock types, such that basaltic rocks showed higher ratio while trachytic rocks showed lower. Saturated resistivity showed close correlation to density and effective porosity of the rock sample, while dry resistivity didn't.

• Journal of the Korean Geosynthetics Society
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• v.10 no.4
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• pp.113-121
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• 2011

River sand has generally used for the backfill material of underground power cables. The thermal resistivity of it has $150^{\circ}C$-cm/Watt in wet condition and more than double in dry condition. The final goal of this study is to find the backfill material which has a small change in thermal resistivity with various water contents, for example thermal resistivity is $50^{\circ}C$-cm/Watt and $100^{\circ}C$-cm/Watt in wet and dry conditions respectively. In this study it is presented that the comparison of thermal resistivity using stone powder, crush rock, weathered granite soil and Jumunjin sand as well as river sand in the needle method regarding water content, dry unit weight and particle size distribution. As a result, the thermal resistivity of a material is minimized when they have maximum dry unit weight at optimum moisture content and maximum density by appropriately mixing materials for particle size distribution. Therefore thermal resistivity characteristics should be considered two factors: one is the difference between natural dry condition and dry state after optimum moisture content, and the other is the difference between unit weight of raw material and maximum dry density.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.575-584
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• 2015

Drought stress is a crucial environmental factor determining crop survival and productivity. The goal of this study was to clearly identify a new drought stress-tolerance gene in Brassica rapa. From KBGP-24K microarray data with the B. rapa ssp. pekinensis inbred line 'Chiifu' under drought stress treatment, a gene which was named BrDSR (B. rapa Drought Stress Resistance) was chosen among 738 drought-responsive unigenes. BrDSR function has yet to be determined, but its expression was induced over 6-fold by drought. To characterize BrDSR, the gene was isolated from B. rapa inbred line 'CT001' and found to contain a 438-bp open reading frame encoding a 145 amino acid protein. The full-length cDNA of BrDSR was used to construct an over-expression vector, 'pSL100'. Tobacco transformation was then conducted to analyze whether the BrDSR gene can increase drought tolerance in plants. The BrDSR expression level in T1 transgenic tobacco plants selected via PCR and DNA blot analyses was up to 2.6-fold higher than non-transgenic tobacco. Analysis of phenotype clearly showed that BrDSR-expressing tobacco plants exhibited more tolerance than wild type under 10 d drought stress. Taking all of these findings together, we expect that BrDSR functions effectively in plant growth and survival of drought stress conditions.

• Geophysics and Geophysical Exploration
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• v.18 no.3
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• pp.105-114
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• 2015

A long-term resistivity monitoring system has been developed for saturated cores in room temperature and humidity condition. A 3-channel water-pump continuously drops the water onto the top of saturated core sample surrounded by shrinkable tube as well as on the paper filters of the electrodes at both sides of the core sample, by which one can monitor the resistivity changes with maintaining full saturation of the rock core for a week or longer. Monitoring the resistivity changes has been performed with 3 kinds of rock samples including biotite gneiss, andesitic tuff, and shale for 9 days using the system. Consequently, it is proposed two hypothesis that conversion speed of temperature coefficient has close relation to the thermal properties of the rock sample and that the ratio of resistance between dry and saturated conditions for a rock sample can be related to the effective porosity of the sample. The ratio between dry and saturated resistance for the three rock types are 48, 705, and 2, while effective porosity was 3.7%, 3.3%, and 13.0%, respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.409-410
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• 2009

The eco-cement concrete using fly-ash was produced for the improvement of the compressive strength of the eco-cement concrete under the long term age, and compressive strength test, drying shrinkage test, uniaxial restraint shrinkage cracking test, and bond test were carried out. In this study, the cracking resistance performance was investigated.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.410-411
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• 2015

765kV 송전선로와 선하 건조물은 최하단 도체의 높이 28m를 적용하고 대지저항률은 $100{\Omega}m$, IEEE 변전소 설계지침인 Std-80에 따라 건조물에 접촉하는 사람의 인체저항은 $1000{\Omega}m$, 대지를 딛고 있는 사람의 한쪽 발 접지저항은 직경 8cm의 원판 접지저항을 적용한다. 이렇게 구성된 모델에서 선로중심에서 건조물까지 이격거리 변동에 따라 인체 유도전류를 측정하고자 한다. 본 연구에서는 전기안전 실증시험을 위해 765kV 가공송전선로 직하에 목조 및 샌드위치 판넬 2가지 시험용 가옥을 설치하였다. 전기설비기술기준에 의거하여 선하직하 이격거리가 28m일 때 발생할 수 있는 전자계 특성과 재질에 따른 전자계가 미치는 영향을 비교 분석하고 장기 유도장해 실측 데이터를 확보하고자 그림 1과 같이 구축 설계하였다. 이를 통해 송전선로에 의해 선로중심으로부터 구축된 모의가옥까지 이격거리에 따라 유도되는 전류를 측정하고 그 크기가 인체에 미치는 유도전류 한계치 초과 여부에 대해 검토함으로써 안전성 여부에 대해 측정 및 검토하고자 시험게획을 수립하였다. 또한 선로 고장 시 대지전위상승에 의한 선하 건조물 안정성 검토 및 낙뢰서지 유입에 의한 전기안전 시험 구성을 하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.795-797
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• 2013

This paper describes a charge sharing capacitive-sensing circuit technique that improves the quality of images captured with fingerprint sensor LSIs. When the finger is dry, the electrical resistance of a finger surface is high. It leads to poor image quality. To capture clear images even when the finger is dry, the modified capacitive detection circuit improves the image quality using an enhancement plate at the finger surface and a voltage control circuit. The test circuit is analyzed on $0.35{\mu}m$ CMOS process.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04a
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• pp.43-43
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• 1999

98년말 동일제지에 도입 설치된 Condebelt 설비는 세계 최초의 대형생산설비로 국제적 인 관심을 모으고 있다. 이러한 첨단 Condebelt 기술의 국산화를 위해서는 국내 원료 특성 에 적합하도록 공정최적화가 요청된다. 본 연구에서는 KOCC를 원료로 이용한 라이너지를 C Conde belt를 이용하여 생산할 경우 주요 공정변수에 따른 물성 변화를 평가하고, 이를 통하 여 Condebelt 공정을 최적화하고자 실험실용 파일로트 건조기를 이용하여 Condebelt 공정의 주요 변수가 지질에 미치는 영향을 검토하였다. 실험용 Condebelt 건조장치의 상부플레이트는 18WC까지, 하부플레이트는 냉각수를 이용 하여 40-80'C까지 조절이 가능하도록 설계하였으며, 유압을 이용하여 압체 압력과 시간을 변화시킬 수 있도록 하였다. 구축된 실험장치를 이용하여 Conde belt 공정의 주요 변수인 온도, 압력, 압체시간, 유입 지필의 건조도 변화에 따른 라이너지의 물성 변화를 평가하고 이를 실린더 건조된 종이의 물성과 비교하였다. 그 결과 본 연구에서 검토된 모든 건조조건에서 Conde belt 건조된 종이가 실린더 건조 된 종이보다 높은 강도를 나타내었으며, 투기저항성과 광택도 역시 향상되었다. 투기저항성 과 광택도는 강도적 성질과 달리 유입지 건조도가 높을수록, 상부플레이트의 온도가 높을수 록 그 효과가 저하되었다. 일반적으로 KOCC를 원료로한 라이너지를 Conde belt로 제조할 경우 상부 고온챔버의 온도를 160'C, 압체압력을 5 bar로 조절하는 것이 가장 좋을 것으로 판단되었다. 원료펄프의 조성에 따른 Condebelt 공정의 건조효과를 연구한 결과 모든 펄프에서 공히 C Condebelt 건조방법이 실린더 건조방법에 비하여 물성 향상 효과가 있는 것으로 나타났으 며, 그 효과는 펼프의 리그닌 함량이 높을수록 크게 나타났다. 또 Condebelt의 물성개선 특 성을 이용한 원료비 절감 가능성을 평가하기 위해 AOCC와 KOCC를 이용하여 단층지와 이 층지를 제조하고 물성을 비교평가하였다. 그 결과 Condebelt를 이용하면 KOCC의 비율을 증가시키더라도 AOCC만을 이용하여 실린더 건조한 종이보다 우수한 물성을 얻을 수 있었다. 이러한 연구를 통하여 Condebelt 공정이 국내 저급원료로 제조된 종이의 강도 저하를 극복할 수 있는 기술임을 확인하였다.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.479-486
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• 2010

Tolerance against heat, sanitizers, and antibiotics of 112 Cronobacter isolates classified by desiccation was determined to permit effective biocontrol in powdered foods. The isolates were classified into three groups: dry-tolerant (n=37), dry-sensitive (n=7), and dry-intermediate (n=68). The strains that were highly tolerant to drying also showed high heat tolerance that they seemed to have high tolerance to heat after dry stress in powdered foods like infant formula. Sodium hypochlorite and benzalkonium chloride concentrations necessary to achieve a 5-log reduction in viable counts (CFU/mL) were 15-25 ppm and 5-15 ppm, respectively. However, there was little difference of the efficacy of these sanitizers between dry-sensitive and -tolerant strains for planktonic cells suspended in 3% albumin. The minimal inhibition concentration (MIC) of $\beta$-lactam ampicillin was 64-128 ppm for 90% of the strains. The isolates were consistently sensitive to kanamycin and naldixic acid (MIC=4 ppm). Dry-tolerant strains displayed more antibiotic resistance than dry-sensitive strains. The results indicate that dry-tolerant Cronobacter isolates often possess heat and antibiotic resistance, indicated the need for potent sterilization treatments of powdered foods.