• 한국세라믹학회지
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• 제33권10호
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• pp.1163-1169
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• 1996

The effects of borax on the phase formation of C2S, C4A3 and $\alpha$'-C2S phases. It has negative effects on formation of C4A3 And it lowers the forming temperature of C4AF. It also has been found that borax improves the clinkerization of MBC. In the MBC clinker with borax 3% C2S have larger and more irregular shapes, larger C/S mole ratio and C4A3 have smaller size larger C/ molr ratio than in the clinker without borax.

• Journal of the Korean Data Analysis Society
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• 제20권6호
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• pp.2721-2731
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• 2018

This study purposes to derive the predictive model for the cold tolerance of Brassica napus, using the data collected in the Tree Breeding Lab of Gyeongsang National University during July and August of 2016. Three Brassica napus samples were treated at each of low temperatures from $4^{\circ}C$ to $-12^{\circ}C$ by decrement of $4^{\circ}C$, step by step, and electrolyte leakage levels were measured at each stage. Electrolyte leakages were observed tangibly from $-4^{\circ}C$. We tried to fit the six nonlinear regression models to the electrolyte leakage data of Brassica napus: 3-parameter logistic model, baseline logistic model, 4-parameter logistic model, (4-1)-parameter logistic model, 3-parameter Gompertz model, and (3-1)-parameter Gompertz model. The baseline levels of the electrolyte leakage estimated by these models were 4.81%, 4.07%, 4.19%, 4.07%, 4.55%, and 0%, respectively. The estimated median lethal temperature, LT50, were $-5.87^{\circ}C$, $-6.31^{\circ}C$, $-6.05^{\circ}C$, $-6.35^{\circ}C$, $-4.98^{\circ}C$, and $-5.15^{\circ}C$, respectively. We compared and discussed the measures of goodness of fit to select the appropriate nonlinear regression model.

• 생물환경조절학회지
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• 제7권1호
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• pp.15-24
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• 1998

태양열 에너지의 효율적인 이용과 자동화 장치의 개발을 목표로 지중가온의 온도변화 특성을 실험. 분석한 결과는 다음과 같다. 1) 10월 13일의 1일 하우스 내기온이 주야간에 24$^{\circ}C$의 차이가 있으며, 무가온시 지온변화는 지중 10 m 부근에서 6$^{\circ}C$, 지중 20 cm 부근에서는 3$^{\circ}C$정도의 차이를 보이고 있다. 2) 20시경에 내기온과 지온차가 가장 작은 것으로 나타났으며, 지중 20 cm 부근의 온도변화는 내기온이 가장 낮은 오전 7시부터 약 3시간이 경과된 오전 10시에 최저가 되었다 3) 가온수의 온도를 4$0^{\circ}C$, 5$0^{\circ}C$, 6$0^{\circ}C$로 변화하였을 때 지중 10 cm의 최저은도는 약 2$0^{\circ}C$ 지중 20 cm의 최저온도는 약 23$^{\circ}C$로 나타나 가온온도가 4$0^{\circ}C$ 이상일 경우 가온온도에 따른 지중 10~20 cm사이의 온도차는 매우 작았다. 4) 지중 15~20 cm의 지온이 2$0^{\circ}C$가 되기 위해서는 가온수의 온도를 4$0^{\circ}C$ 이하가 되도록 설정하여야한다. 5) 가온수의 온도가 4$0^{\circ}C$, 5$0^{\circ}C$, 6$0^{\circ}C$이고 파이프 매설 깊이가 12 m일 경우 유입구와 유출구의 1일 평균온도차는 4$0^{\circ}C$일 경우 3.5$^{\circ}C$ 5$0^{\circ}C$일 경우 4.4$^{\circ}C$, 6$0^{\circ}C$일 경우 5.4$^{\circ}C$정도로 이 구간에서 온도변화식은 T = 0.09591T＋2.5451($R^2$= 0.9966)로 거의 선형적으로 변화하였다. 6) 가온수 온도가 4$0^{\circ}C$의 경우 지중 15~20 cm, 5$0^{\circ}C$의 경우는 지중 13~19 cm, 6$0^{\circ}C$의 경우는 12~17 cm 부근이 경계영역으로 판단되었다. 7) 재배기간중 하우스 내기온을 11$^{\circ}C$ 이상으로 유지하고, 가온수의 온도를 28$^{\circ}C$로 순환 결과 지중 15 cm 이하에서 최저지온를 2$0^{\circ}C$ 이상의 온도를 유지할 수 있어 저온수공급에 의한 온도상승효과가 뚜렷이 나타났다. 8) 가온수의 온도를 28$^{\circ}C$로 하여 지중가온 한 결과 지중 15~20 cm사이에 온도변화는 무가온구에 비하여 공히 4$^{\circ}C$~7$^{\circ}C$가 상승되었다.

• 센서학회지
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• 제18권1호
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• pp.54-62
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• 2009

${Co_3}{O_4}$ and ${Co_3}{O_4}$-based thick films with additives such as ${Co_3}{O_4}-{Fe_2}{O_3}$(5 wt.%), ${Co_3}{O_4}-{SnO_2}$ (5 wt.%), ${Co_3}{O_4}-{WO_3}$(5 wt.%) and ${Co_3}{O_4}$-ZnO(5 wt.%) were fabricated by screen printing method on alumina substrates. Their structural properties were examined by XRD and SEM. The sensitivities to iso-${C_4}H_{10}$, $CH_4$, CO, $NH_3$ and NO gases were investigated with the thick films heat treated at $400^{\circ}C$, $500^{\circ}C$ and $600^{\circ}C$. From the gas sensing properties of the films, the films showed p-type semiconductor behaviors. ${Co_3}{O_4}-{SnO_2}$(5 wt.%) thick film heat treated at $600^{\circ}C$ showed higher sensitivity to i-${C_4}H_{10}$ and CO gases than other thick-films. ${Co_3}{O_4}-{SnO_2}$(5 wt.%) thick film heat treated at $600^{\circ}C$ showed the sensitivity of 170 % to 3000 ppm iso-${C_4}H_{10}$ gas and 100 % to 100 ppm CO gas at the working temperature of $250^{\circ}C$. The response time to i-${C_4}H_{10}$ and CO gases showed rise time of about 10 seconds and fall time of about $3{\sim}4$ minutes. The selectivity to i-${C_4}H_{10}$ and CO gases was enhanced in the ${Co_3}{O_4}-{SnO_2}$(5 wt.%) thick film.

• 한국세라믹학회지
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• 제35권12호
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• pp.1241-1248
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• 1998

$\beta$-C2S and C4A3 were synthesized separately and potassium oxalate was added to each system. The ad-ditive caused calcium ions in solution to decrease at early time in hydration and promoted hydration reac-tion. And then clinker which is mainly composed of $\beta$-C2S and C4A3 was synthesized at 130$0^{\circ}C$ After ad-ding potassium oxalate to it behavior of hydration was observed. It showed that the additive promoted et-tringtie formation at early time and C-S-H formation as time went on.

• 대한화학회지
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• 제34권6호
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• pp.517-526
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• 1990

D-glucitol hexaacetate 와 xylitol pentaacetate의 결정구조를 단결정 X-선 회절법으로 연구하였다. D-glucitol hexaacetate 는 공간군 P2$_1$, 단위세포 상수는 a = 10.275 (2), b = 8.363 (1), c = 12.560 (5) $\AA$, $\beta$= 95.97 $(2)^{\circ}$; Z = 2이고, xylitol pentaacetate는 공간군이 P2$_1$/C이고, a = 18.126 (1), b = 11.422 (2), c = 8.649 (1) $\AA$, $\beta$ = 95.03 $(1)^{\circ}$이며 Z = 4이다. 회절세기는 diffractomerer로 얻었고, 분자구조는 직접법으로 밝혔으며, 최소자승법으로 정밀화하였다. 두 분자에 결쳐 결합의 평균길이는 C($sp^3)-C(sp^3$)가 1.514 (10), C($sp^3)-O: 1.444 (6),\; C(sp^2)-O: 1.347 (9),\; C(sp^2)=O: 1.197 (6),\; C(sp^2)-C(sp^3): 1.479(9){\AA}$이고, 평균 결합각도는 C($sp^3)-C(sp^3)-C(sp^3): 114.6 (17),\; O-C(sp^3)-C(sp^3): 109.4 (23),\; C(sp^2)-O-C(sp^3): 117.4 (6),\; O=C(sp^2)-O: 122.6 (6),\; C(sp^3)-C(sp^2)-O: 111.8 (7), C(sp^3)-C(sp^2)=O: 125.5 (4)${\circ}$이다. 두 분자내의 탄소 사슬들은 extended zigzag chain으로 되어 있어 D-glucitol과 xylitol 분자들의 conformation과는 다르다. Acetate group들의 각 원자들은 모두 한 평편상에 놓여있다.

• 자원리싸이클링
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• 제14권5호
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• pp.13-17
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• 2005

용융전로슬래그를 일반 포틀랜드 시멘트로 활용하기 위하여, 용융슬래그와 $C_3A(3CaO{\cdot}Al_2O_3)$가 반응하여 시멘트의 구성상인 $C_4AF$가 생성되는 기구와 생성속도를 조사하고자 한다. 전로슬래그에 소정의 $SiO_2$를 첨가하여 MgO도가니에 넣고 $1300^{\circ}C{\sim}1350^{\circ}C$에서 30분간 가열 용해하여 균질화 한 후, 같은 온도로 가열해 둔 소결 $C_3A$펠렛을 투입하여 $10{\sim}30$분간 반응시켰다. 반응 후, 급냉한 시편을 도가니의 직경방향으로 절단해서 펠렛 단면의 $C_3A$직경 변화를 측정하여 $C_3A$의 용해속도를 조사하고, 계면반응 생성상을 SEM/EDX로 관찰하였다. 그 결과 $C_3A$ 펠렛의 슬래그로의 용해속도는 $1300^{\circ}C$에서 $0.75{\times}10^{-4}(cm/sec)$으로부터 $1350^{\circ}C$에서 $1.67{\times}10^{-4}(cm/sec)$으로 증가하였으며, 슬래그와 $C_3A$ 펠렛 사이에 $C_4AF$와 $C_{12}A_7$의 혼합층이 생성됨을 알 수 있었다.

• Journal of Life Science
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• 제10권2호
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• pp.50-54
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• 2000

The RAD4 gene of Saccharomyces cerevisiae is essential for the incision step of UV-induced excision repair. A yeast RAD4 gene has been previously isolated by functional complementation. In order to identify the RAD4 homologous gene from fungus Coprinus cinereus, we have constructed cosmid libraries from electrophoretically separated chromosomes of the C. cinereus. The 13 C. cinereus chromosomes were resolved by pulse-field gel electrophoresis, hybridized with S. cerevisiae RAD4 DNA, and then isolated homologous C. cinereus chromosome. Here, we report the cloning and characterization of fungus C. cinereus homolog of yeast RAD4 gene. Southern blot analysis confirmed that C. cinereus contains the sequence homologous DNA to RAD4 gene and this gene exists as a single copy in C. cinereus genome. When total RNA isolated from C. cinereus cells was hybridized with the 3.4 kb BglII DNA fragment of the S. cerevisiae RAD4 gene, a 2.5 kb of transcript was detected. The isolated gene encodes a protein of 810 amino acids.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.151-151
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• 2000

We have studied the atomic structure of Si(100)-c(4$\times$4) reconstruction using scanning tunneling microscopy(STM). The c(4$\times$4) reconstruction can be formed by annealing the hydrogen exposured surface at temperatures between 850 and 960 K. At this temperature ranges, adsorbed hydrogen atoms are all desorbed. Therefore, the c(4$\times$4) reconstruction is due to the Si dimers on surface. The filled and empty state images of the STM were interpreted in terms of Si dimers in c(4$\times$4) primitive cell forming the reconstruction. Based on the STM images and hydrogen adsorption experiment on c(4$\times$40 surface, we suggest that Si dimers in c(4$\times$40 unit cell are perpendicular ad-dimer to the underlying Si dimer rows.

• 한국세라믹학회지
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• 제30권1호
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• pp.7-16
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• 1993

Effect of sulfate on the reactionof C3S formation in presence of clinker melt and its appearance in clinker were investigated, using (NH4)2SO4 and CaSO4 as sulfate sources. When (NH4)2SO4 and CaSO4 were added, both showed the similar results, 1.0wt% of sulfate could promoted the reaction of C3S formation, however for its content of more than 2.0wt%, the formation of C3S was prevented. Residual limit of sulfate to C3S formation is about 1.4wt%. Appearances of sulfate were C4A3l and CaSO4 in interstitial phase. For the addition of (NH4)2SO4 or CaSO4 of 20wt%~4.0wt%, C3S grains showed the hypertrophic growth. We might consider that, because sulfate reduced the surface tension and viscosity of the clinker melt, C3S crystals were precipitated below 140$0^{\circ}C$, and the crystlas of C3S were coalesced and linked in the same crystallographical direction with increasing temperature becuase of their rapid growth rate.