• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.525-526
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• 2009

본 논문에서는 Sporosarcina pasteurii라는 미생물의 생체광물형성작용을 이용하여 Calcite($CaCO_3$) 석출을 유도하고, 이를 Mortar에 적용하여 요구 성능 향상을 평가하였다. Sporosarcina pasteurii를 혼입(input)한 Mortar 시험체(C3S-S.p)와 일반 Mortar 시험체(C3S-W)의 중성화 반응을 실험을 통해 비교한 결과 C3S-S.p가 C3S-W에 비해 중성화가 지연되는 것을 육안으로 확인할 수 있었다. 또한 28日간 Urea-CaCl2 수용액(Medium)에서 양생한 C3S-S.p와 C3S-W의 내구성을 실험을 통해 비교한 결과 Sporosarcina pasteurii를 혼입한 Mortar 시험체(C3S-S.p)가 일반 Mortar 시험체(C3S-W) 비해 내구성이 향상된 것으로 나타났다.

• 한국세라믹학회지
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• 제26권4호
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• pp.514-520
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• 1989

The early hydration characteristics according to the C3S/C3A ratio and presence of gypsum, in order to establish the hydration mechanism of the system C3S-C3A, have been studied. The rate of C3S dissolution in the system C3S-Gypsum was higher than that in the system C3S. Consequently, the induction period was reduced and the rate of Ca(OH)2 formation in the accleration period was increased. The hydration of C3S in the system C3S-C3A was retarded because Al3+ in the liquid phase originating from the hydration of C3A was incorporated into calcium hydrosilicates formed. The retardation phenomenon of C3S hydration was not appeared in the system C3S-C3A-gypsum because the reaction of monosulfate formation became the rate-determining step.

• 미생물학회지
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• 제33권2호
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• pp.111-117
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• 1997

Virginiamycin(VM) 생산 유도에 관여하는 virginiae butanolide C(VB-C)및 receptor의 기능을 명확히 규명하기 위해 S. virginiae로부터 NTG및 hydroxylamine 처리를 통해 두 개의 변이주를 분리하였으며, VM을 생산하는 균중에서 VB, receptor를 모두 생산하지 않는 S. ostreogriseus와, receptor는 생산하나 VB를 생산하지 않는 S. graminofaciens를 대상으로 하여 유도능의 관계를 검토하였다. 분리한 S. virginiae mutant N-25와 H-05는 VB가 receptor보다 먼저 생산되는 특성을 나타내었으며, VM 생산시기가 현저히 지연되었다. 이는 S. virginiae 모균주에서 receptor가 생사노디기 이전에 합성 VB-C를 첨가하였을 때 VM 생산이 억제되는 것과 같은 현상인것으로 판단되었다. 한편, VM 생산균인 S. ostreogriseus 및 S. graminofaciens는 모두 VB를 생산하지 않으며 합성 VB-C 첨가에 의한 유도능을 검토한 결과, receptor를 생산하지 않는 S. ostreogriseus의 경우 VM 생산이 억제되는 반면, receptor를 생산하는 S. graminofaciens의 경우에는 VM 생산이 촉진되었다. 이들 결과에서 볼 때, VM 생산 촉진에 VB가 필수적이며 VB의 신호전달에 따른 VM 생산 촉진 효과는 반드시 receptor의 존재하에서 일어난다고 사료되었다. S. graminofaciens의 경우 합성 VB-C 첨가에 의해 생산된 하생물질을 HPLC를 이용하여 분석한 결과, 항생물질 생산량이 증가하였으며, 새로운 항생물질 생상 유도도 가능한 것으로 시사되었다.

• 한국안광학회지
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• 제6권1호
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• pp.43-47
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• 2001

구면렌즈와 비구면렌즈를 착용한 피검자의 굴절이상을 중등도근시, 중등도 근시성 복난시, 중등도 혼합난시이상의 착용자를 대상으로 비교하였다. 양안 굴절이상의 구면렌즈 착용자는 S-3.00 ~ S-6.00Dptr 가 16%, S-6.00D Dptr 이상이 19%, S-3.00C-0.50(90.180) ~ S-6.00C-2.00DptrAxis(90.180) 이 57%, S-3.00C+0.50 ~ S-6.00C+2.00DptrAxis(90.180)이 8%로 분포되어 나타났으며, 비구면렌즈 착용자는 S-3.00 S-6.00Dptr이 31%,S-6.00Dptr 이상이 36%, S-3.00C-0.50(90.180) ~ S-6.00C-2.00DptrAxis(90.180)이 21%, S-3.00C+0.50(90.180) ~ S-6.00C+2.00DptrAxis(90.180)이 12%로 분포되었다.

• 한국세라믹학회지
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• 제27권8호
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• pp.1055-1063
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• 1990

The early hydration characteristics of the system $C_3S-C_3A-C_4AF$ according to the clinker composition variations, in order to establish the mutual interactionof clinker minerals during the portland cement hydration, have been studied. The early hydration rate of $C_3S$ was greatly effected by the change of $C_3S/C_3A$ ratio. The lower the $C_3S/C_3A$ ratio was, the faster the apex reaching time and the rate of heat liberation of the 2nd exothermic peak originating from the formation of $Ca(OH)_2$ were. The effect of $C_3S/C_3A$ ration on the amounts of $Ca(OH)_2$ formation was decreased, in process of hydration time, but the effect of $C_3S$ content was increased.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.473-474
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• 2010

C-S-H(I)은 활성슬래그시멘트의 강도생성의 핵심물질이며 시멘트 수화물의 강도원천물질인 C-S-H의 구조모델로 사용되어 왔기 때문에, 나노 수준의 콘크리트 연구 분야에서는 세계적으로 아주 중요한 물질로 다루어지고 있다. 이러한 C-S-H(I)에서 발생되는 Si에 대한 Al 치환은 C-S-H(I)의 분자구조변경을 인위적으로 할 수 있다는 점에서 주목되어 왔고, C-S-H(I)의 기계적 물성치 (예, bulk modulus)에도 큰 영향을 미칠 것이라고 예상되어 왔었다. 그러나 본 연구를 통해 이러한 Al 치환이 실제로는 C-S-H(I)의 bulk modulus에는 거의 영향을 미치지 못함이 밝혀졌다.

• 한국세라믹학회지
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• 제28권4호
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• pp.315-323
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• 1991

The preparation of zirconium carbide powders by the halogenide process of ZrCl4-C-Mg system (1:1:2, molar ratio) was studied between 300。 and 120$0^{\circ}C$ under Ar gas flow (200 mι/min). The formation mechanism and kinetics of zirconium carbide and characteristics of the synthesized powder were examined by TG-DTA, XRD, SEM and PSA. 1) The formation mechanism of zirconium carbide were as follows, above 30$0^{\circ}C$ ZrCl4(S)+Mg(s)longrightarrowZrCl2(s)+MgCl2(s) above 40$0^{\circ}C$ ZrCl2(S)+Mg(s)longrightarrowZr(s)+MgCl2(s) above 50$0^{\circ}C$ Zr(s)+C(s)longrightarrowZrC(s) 2) The apparent activation energy of the reduction-carbonization at temperature of 800$^{\circ}$to 100$0^{\circ}C$ was 11.9 kcal/mol. 3) The lattice parameter and the crystallite size of ZrC which was produced from the mixture powder of ZrCl4, C and Mg (1:1:2, molar ratio) at 100$0^{\circ}C$ for 1 h were 4.700A and 180A, respectively. 4) The powders obtained from the mixture powder of ZrCl4, C and Mg(1:1:2, molar ratio) at 100$0^{\circ}C$ for 1 h were agglomerate with the average size of about 13${\mu}{\textrm}{m}$ in SEM micrograph.

• 한국주거학회논문집
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• 제12권2호
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• pp.191-198
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• 2001

The aim of this research was to examine the thermal performance of the flat roof in proportion to various directional changes, the results of which were drawn from the miniature model experiment. In this process, various thermal environmental factors were measured and compared with one another to research their aspects of changes. The brief results of this research are as follows: 1) The indoor temperature and load per hour in proportion to directional changes shows the same degree of changes. As for the results of the clear-sky and cloudy-sky experiments, both of them generally appear advantageous in the order of S, $S-30^{\cire}C$-E, $S-30^{\cire}C$-W, $S-60^{\cire}C$-W, E, $S-60^{\cire}C$-E, despite slight differences in the indoor temperature and load per hour in proportion to directional changes. 2) As for the total load of degree day per direction of the clear-sky and cloudy-sky experiments, both of them shows their advantageous results in the order of S, $S-30^{\cire}C$-E, $S-30^{\cire}C$-W, $S-60^{\cire}C$-W, E, $S-60^{\cire}C$-E, despite minor differences in their loads. 3) As for the peak load of degree hour, while the clear-sky experiment shows its advantage in the order of $S-30^{\cire}C$-E, S, $-30^{\cire}C$-W, $S-60^{\cire}C$-W, E, $S-60^{\cire}C$-E, the cloudy-sky experiment does so in the order of S, $S-30^{\cire}C$-E, $S-30^{\cire}C$-W, E, $S-60^{\cire}C$-W, $S-60^{\cire}C$-E.

• 대한화학회지
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• 제10권4호
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• pp.166-174
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• 1966

cinnamoylated photosensitive polymer의 광증감 경화반응기구를 반응속도론적으로 연구했다. Cinnamic acid(C)와 증감제(S)의 first excited singlet and lowest triplet energy level diagram과 증감제의 농도증가에 따른 sensitivity의 포화 등의 사실로부터 이 반응의 주요과정은 C와 S의 광 energy흡수에 의한 $C^{*(1)}$ 및 $S^{*(1)}$로의 여기, $S^{*(1)}{\to}S^{*(3)}$ intersystem crossing, S의 excimer 형성, $S^{*(3)}{\to}C^{*(3)}$ energy transfer 그리고 $C^{*(3)}$와 C의 termination 등임을 가정하고 다음 반응속도를 구했다. $-\frac{d[C]}{dt} = \frac{K_1[C]}{K_2 + [C]}[\frac{I^c_{abs}}{K_3 + [S]} + \frac{K_4[C]}{(K_5 + [C])(K_6 + [S])}(I^s_{abs} + \frac{K_7I^c_{abs}[S]}{K_8 + [S]})]$ $I^c_{abs}$와 $I^s_{abs}$ ;C 및 S의 광흡수율 $K_n$;상수 적외선 흡수스펙트럼 분석의 결과, Cinnamoyl 에스테르화도와 sensitivity의 관계 및 증감제의 농도와 sensitivity의 관계에 대하여 발표된 실험 data는 윗식을 만족시키므로 가정한 반응기구에 대한 뒷받침을 얻었다.

• Journal of Korean Neurosurgical Society
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• 제64권6호
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• pp.913-921
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• 2021

Objective : Accurate measurement of T1 slope (a component of T1s minus cervical lordosis [CL]) is often constrained by anatomical limitations. In this situation, efforts should be made to find the exact meaning of T1s-CL and whether there are any alternatives to it. Methods : We enrolled 117 patients who received two-level anterior cervical discectomy and fusion (ACDF). Occipital slope, C2 slope (C2s), C7 slope (C7s), T1, O-C2 angle (O-C2A), C2-7 angle (C2-7A), O-C7 angle (O-C7A), T1s-CL, C7-T1 angle (C7-T1A), and C2-7 sagittal vertical axis were measured. We determined 16° (T1s-CL) as the reference point for dividing subjects into the mismatch group and the balance group, and a comparative analysis was performed. Results : The mean value of C7-T1A was constantly maintained within 2.6° peri-operatively. In addition, C2s and T1s-CL showed the same absolute change (Δ|0.8|°). The mean values of T1s-CL of the mismatch and balance groups were 23.0° and 7.6°, respectively. The five factors with the largest differences between the two groups were as follows : C2s (Δ13.3°), T1s-CL (Δ15.4°), O-C2A (Δ8.7°), C2-7A (Δ14.7°), and segmental angle (Δ7.9°) before surgery. Only four factors showed statistically significant change between the two groups after ACDF : T1s-CL (Δ4.0° vs. Δ0.2°), C2s (Δ3.2° vs. Δ0.7°), O-C2A (Δ2.6° vs. Δ1.3°), C2-7A (Δ6.3° vs. Δ1.3°). A very strong correlation between T1s-CL and C2s was also found (r=|0.88-0.96|). Conclusion : C2s itself may be the essential key to represent T1s-CL. The amounts and directions of change of these two factors (T1s-CL and C2s) were also almost identical. The above phenomenon was re-confirmed once again through the correlation analysis.