• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(4)
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• pp.413-418
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• 1996

To derive the optimimum antenna launching condition for fast wave current drive, the propagation and absorption of the ion cyclotron range of frequencies waves are studied in a KT-2 tokamak plasma. We sove the kinetic wave equation in one dimensional slab geometry with the phase-shifted antenna array to inject the toroidal momentum to electrons. The accessibility conditions and the guidelines of the optimum antenna design for the efficient current drive are derived. The dependence of the current drive efficiency on launching conditions such as the phase and spacing Is presented.

• 한국자기학회지
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• 제4권4호
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• pp.347-354
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• 1994

밀링 및 화학적 처리에 의해 제조된 소재의 구조해석 및 자기적 특성은 X선회절, 투과 전자현미경, 쾨스바우어 분광 및 비탄성 중성자산란 등의 측정에 의해 조사되었다. 질화처리에 의해 제조된 ${\gamma}'-Fe_{4}N$분말의 기계적 밀링처리에 의해, 대부분의 fcc ${\gamma}'-Fe_{4}N$상은 밀링 초기단계에 bct ${\alpha}'-Fe(N)$상으로 변태를 하며, 이러한 변태는 응력유기 마르텐사이트 변태로 규정지을 수 있다. 밀링처리에 제조한 bct ${\alpha}'-Fe(N)$ 초미세 분말의 열처리에 의해 673~773 K의 온도범위에서 ${\alpha}'-Fe_{16}N_{2}$상이 부분적으로 생성되며, 이로 인해 포화자화값이 증가한다. Mn-45, 70, 85 at.% Al의 조성으로 혼합한 분말은 기계적 합금화에 의해, Al은 부분적으로 ${\alpha}-Mn$상에 고용된다. 이로 인해 ${\alpha}-Mn$형 Mn-Al합금의 자기적 성질은 상자성에서 강자성으로 특성이 변하며, 특히 밀링처리한 Mn-70 at.% Al 계에 있어서 포화자화값은 11 emu/g을 나타낸다. 한편, 밀링처리한 Mn-85 at.% Al계에서 화학적 추출법을 이용하는 것에 의해 skeleton-type의 순 ${\alpha}-Mn$분말상을 제조한 결과 포화자화값은 36 emu/g으로 급격히 증가하였다.

• 한국연초학회지
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• 제30권2호
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• pp.109-116
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• 2008

Mutagenicity of cigarette smoke is one of the major health concerns related to smoking. Reduction of the components comprising mutagenic activity in cigarette mainstream smoke can be expected to bring about reduced risk of smoking. The purpose of this study is to isolate mutagenic compounds and to investigate the relative contribution to allover mutagenicity of smoke to find clues for the effective elimination of the components. Cigarette smoke condensate (CSC) was obtained from total particulate matter (TPM) of mainstream smoke, and several fractions fractionated from CSC were made by combination of cation exchange chromatograph and reverse-phase chromatography. The mutagenic activity of these fractions was assessed using Salmonella mutagenicity assay with S. typimurium TA98 strain in the presence of metabolic activation system (S-9). The fractions isolated by cation exchange and reverse-phase column showed relatively high mutagenic activity. The basic and hydrophilic fraction 9 showed approximately 33% of mutagenic activity of CSC and its specific activity was 2,459 revertants/mg TPM. These results suggest that hydrophilic cation exchanger and/or other adsorbents possessing similar properties may be used to remove the mutagenic compounds from mainstream smoke.

• 분석과학
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• 제14권1호
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• pp.44-49
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• 2001

GC-MS와 연결된 $85{\mu}m$ 폴리 아크릴레이트 fiber의 SPME가 풍선 시료 중에 포함된 가소제를 분석하는데 사용되었다. 풍선은 IR 분광법에 의해 폴리이소프렌으로 만들어진 것으로 판명되었다. 한시간 동안 아세톤이 첨가된 물 용매에서 추출된 풍선의 가소제는 9종류의 가소제가 포함된 외부표준법에 의해 정량 하였다. 정량법은 $0.25-25{\mu}g/g$의 농도범위에서 표준 가소제들에 대하여 유효화 과정을 거쳤으며, 검출한계는 가소제에 따라 $0.11-0.38{\mu}g/g$이었고, 이러한 정량법에 의한 재현성의 RSD는 3.7-14.2%이었다. 이들 풍선 중에는 우려할만한 수준의 환경호르몬성 가소제가 검출되는 제품도 포함되어 있어 이들에 대한 규제의 필요성이 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제24권9호
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• pp.1256-1267
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• 2011

Two experiments were conducted to determine the effects of dietary lysine and energy level on performance and apparent total tract digestibility (ATTD) of nutrients in weanling pigs. In Exp. 1, a total of 288 weaned pigs (initial BW $5.77{\pm}0.85\;kg$) were randomly allotted to 4 treatments (4 replicates per treatment with 18 pigs in each replicate). Experimental diets were fed in the 3 phases: phase I (d 0 to 7), phase II (d 8 to 14) and phase III (d 15 to 28). Isocalorific diets (3,450 kcal/kg) with incremental lysine levels (Phase I: 1.51, 1.61, 1.71 and 1.81; Phase II: 1.35, 1.46, 1.56 and 1.66; Phase III: 1.18, 1.28, 1.39 and 1.49% lysine respectively for T1, T2, T3 and T4) were used as treatments. An increase in the dietary lysine levels linearly improved (p<0.05) the ADG and G:F during phases I, II and III as well as overall study period. The ATTD of DM (d 7 and 28) and CP (d 7, 14 and 28) were linearly improved (p<0.05) with increasing dietary lysine levels. ATTD of ash, Ca and P were not affected by dietary lysine level. In Exp. 2, 64 weanling pigs (initial BW $4.79{\pm}0.79\;kg$) were randomly allotted to 4 treatments (4 replicates per treatment with 4 pigs in each replicate) in a $2{\times}2$ factorial arrangement on the basis of BW. Effects of two levels of energy (high, 3,450 or low, 3,350 kcal/kg) and lysine (high or low; 1.70 or 1.50, 1.55 or 1.35 and 1.40 or 1.20% in phase I, II and III diets, respectively) on performance and ATTD of nutrients were investigated. High energy and lysine diets improved ADG (p<0.05) in pigs during phase I, II and III and overall period (p<0.001), while G:F increased (p<0.05) during phase I and overall period. Pigs fed high lysine diets consumed more (p<0.05) feed during phase III and overall period. Additionally, pigs fed high energy diets had greater (p<0.05) ATTD of GE (d 7 and 14), CP (d 7 and 28) and DM (d 28); whereas, pigs fed high lysine diets had greater (p<0.05) ATTD of GE and CP during d 7, 14 and 28. ATTD of ash, Ca and P remained unaffected (p>0.05) by dietary energy and lysine level. However, there was no energy${\times}$lysine interaction for any of the measured variables. Results obtained in present study suggested that high energy and lysine level improve the growth performance and ATTD of nutrients in weanling pigs.

• Parasites, Hosts and Diseases
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• 제29권2호
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• pp.121-128
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• 1991

Toxoplasma gondii를 HL-60 세포와 함께 in vitro 배양시 Toxopsasma 침투 정도가 각 세포에서 균일하지 않으므로 세포의 주기에 따른 일정 phase가 그 침투에 좋은 환경을 제공할 것이라는 추론으로 HL-60세포 주기를 동시화(synchronization)하여 각 stage에서 변화를 관찰하였다. 동시화는 과량의 thymidine이 DNA 합성을 억제함을 이용하여 2mM thymidine을 10시간 간격으로 각 24, 18시간 동안 처리하여 (double thymidine block method) S (synthetic) phase를 진행하는 세포를 얻었고 이후 30시 간 동안 13회의 간격을 두고 $5{\times}10^6/ml$의 Toxoplasma를 첨가하여 1시간 동안 배양하였다. 숙주세포의 동시화 정도는 (1) 3H-thymidine의 표지량 (2) mitotic index 측전 및 (3) 세포수의 증가를 통해 확인하였다. Toxoplasma의 침투 정도는 S phase중에서도 배지에서 thymidine을 제거한 후 3시간 경과시가 그 전후에 비해 6배 이상 높았으며 특히 이 시기는 DNA 합성이 최고가 되는 점과 일치하였다. 침투된 Toxoplasma 수의 변화 외에 세포의 모양도 상당한 변화가 있었고 이는 19시간 후 2번째 S phase에서도 약하나마 관찰되었다 실험 결과를 통해 특정 약 1시간 동안 일어나는 어떤 세포의 변화가 Toxoplasma 침투에 중요한 역할을 한다는 것을 알 수 있었다. 이는 원충 기생충의 숙주세포 흡착과 interiorization과정에 receptor가 관련되고 몇 receptor는 세포주기에 따라 발현이 조절되는 사실로부터 $G_1/S$ 경계부터 3시간째에 발현되면서 Togopzasma를 유인하는 receptor molecule의 존재 가능성을 시사하였다.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1985-1992
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• 2011

The stable conformers of glycine and the inter-conversions between them were studied theoretically at various levels of theory, B3LYP, MP2, CCSD and CCSD(T), in the gas phase and in aqueous solution. In aqueous solution, the structures examined by use of the conductor-like polarizable continuum model (CPCM) with various cavity models, UA0, UAHF, UAKS, UFF, BONDI and PAULING, and by use of a discrete/continuum solvation model with eight water clusters. The Gibbs free energy differences between the neutral (NE) and zwitterionic conformers (ZW), ${\Delta}G_{Z-N}[=G_{ZW}-G_{NE}]$, in aqueous solution were well reproduced by using the BONDI and PAULING cavity models. However the ${\Delta}G_{Z-N}$ values were underestimated in other cavity models, although the ZW conformers existed as stable species in aqueous solution. In the studies of a discrete/continuum solvation model with eight water clusters, gas phase results are still insufficient to reproduce the experimental findings. However the ${\Delta}G_{Z-N}$ values calculated by use of CPCM method in aqueous solution agreed well with the experimental ones.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.605-609
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• 2001

Low density ceramic supporter was prepared by using fly ash as a starting material for the application to the biological aerated filter (BAF) system, and the effect of additives and sintering atmosphere on the apparent and bulk density of the carrier was examined. Borax, Na$_2$O and glass powders were added to produce liquid phase. The density of the supporter decreased as the amount of borax increased. The bulk density of 0.79 g/㎤ and the apparent density of 1.10 g/㎤ were obtained when the fly ash with 15% of borax was sintered at 116$0^{\circ}C$ for 15 minutes. The density also decreased as the plate glass powders past through 22${\mu}{\textrm}{m}$ size were mixed. When the fly ash with 12% of grass powder was sintered at 128$0^{\circ}C$ for 10 minutes, the bulk and apparent density were 0.90g/㎤ and 1.00 g/㎤, respectively. Apparent density of 1.6~1.8g/㎤ was obtained when the fly ash was sintered at 120$0^{\circ}C$ in a weak reducing atmosphere. By maintaining the reducing atmosphere and sintering at a high heating rate, the liquid phase was farmed from the reduced composition of fly ash. This resulted in the formation of closed pores that enabled the low apparent density.

• KSBB Journal
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• 제4권3호
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• pp.241-245
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• 1989

Streptomyces erythreus의 포자를 다공성의 celite를 담체로 이용하여 미세구멍조직내에 흡착 후 배양하여 얻은 균사 증식 담체를 erythromycin의 발효에 응용하였다. 이때 균사체는 담체의 내부에서부터 포자가 발아하여 담체 표면으로 성장되어 나왔기 때문에 부착성이 강하고 매우 안정한 biofilm growth를 보여 주었다. 발효시 배지중의 com steep liquor의 양을 0.8g/L 첨가하여 인산원의 농도를 40mg $KH_2PO_4/L 정도로 하였을 때 항생제 비생산 속도는 최대값 2,898$\mu$g/g.cell.hr로서 인산원이 제한되지 않은 배지에서 얻은 비생산속도 557$\mu$g/g.cell.hr보다 약 4배의 증가효과를 보였다. 유동층 반응기를 이용한 연속 발효 공정에서도 인산원의 제한에 의하며 세포의 항생제 합성 활성은 약 600시간 이상 유지 되었다.

• 한국수정란이식학회지
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• 제31권3호
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• pp.199-205
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• 2016

The aim of this study was to investigate the effect of uterine histotroph on embryo development and the expression of cysteine-rich protein 2 (CRP2), coatomer subunit gamma-2 (G2COP), myoglobin (MYG), vascular endothelial growth factor D (VEGFD), collagen alpha 4 chain (COL4) and galactoside 3-L-fucosyltransferase 4 (FUT4) proteins in porcine embryo during pre-implantation. Uterine histotroph (UH) was collected from uterine horn on corpus albican phase, and embryos were cultured in porcine zygote medium with UH for 168 hours. Cleavage and blastocyst formation of embryo were detected at 168 hours after in vitro fertilization. And CRP2, G2COP, MYG, VEGFD, COL4 and FUT4 proteins were observed using confocal laser microscope. In results, embryo cleavage rate was not significantly changed by UH, but blastocyst rate was significantly (P<0.05) decreased in UH-treated embryos. Moreover, CRP2, G2COP, MYG, VEGFD, COL4 and FUT4 proteins were expressed in blastomere. CRP2 in embryo was significantly overexpressed (P<0.05), but not G2COP, MYG, VEGFD, COL4 and FUT4 proteins. In summary, UH on corpus albican phase was increased CRP2 protein in embryo, and inhibited blastocyst formation in preimplantation porcine embryos, suggesting that CRP2 may play an interrupter on embryo development in pigs.