• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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• pp.123-132
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• 2002

A numerical study was conducted to investigate the combustion phenomena of normal start and unstart processes based on ISL's RAMAC 30 experiments with different diluent amounts and fill pressures in a ram accelerator. The initial projectile launching speed was 1.8 km/s which corresponded to the superdetonative speed of the stoichiometric $H_2/O_2$ mixture diluted with 5 $CO_2$ or 4 $CO_2$. Experiments with same condition except for projectile surface material demonstrated that ignition was successful with an aluminum projectile, but no combustion was observed in case of a steel projectile. In this study, it was found that neither shock nor viscous heating was sufficient to ignite the mixture at a low speed of 1.8 km/s, as was found in the experiments using a steel projectile. However, we could succeed in igniting the mixtures by imposing a minimal amount of additional heat to the combustor section and simulate the normal start and unstart processes found in the experiments with an aluminum projectile. For the numerical simulation of supersonic combustion, multi-species Navier-Stokes equations coupled with a Baldwin-Lomax turbulence model and detailed chemistry reaction equations of $H_2/O_2/CO_2$ suitable for high-pressure gaseous combustion were considered. The governing equations were discretized by a high order accurate upwind scheme and solved in a fully coupled manner with a fully implicit, time accurate integration method. The numerical results matched almost exactly to the experimental results. As a result, it was found that the normal start and unstart processes depended on the strength of gas mixture, development of shock-induced combustion wave stabilized by the first separation bubble, and its size and location.

• 대한바이러스학회지
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• 제30권1호
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• pp.61-70
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• 2000

Standard plaque assay using agarose-overlay has long been used for titration of many infectious virus particle. Plaque assay for the titration of varicella-zoster virus and its live vaccine requires three intermittent agarose overlay to visualize plaques. Overall procedure of the assay takes at least nine days from virus inoculation and microbe contamination including fungi is frequently accompanied during incubation period. We studied whether an immunofocus assay in conjunction with peroxidase-mediated immunohistochemical reaction may replace the standard plaque assay for the virus titration by comparing the two methods. A linear relationship was observed between number of foci and virus dilution. The number of foci in a given dilution of virus appeared a little higher than counted plaques formed in standard plaque assay. Independent titration results obtained from two assay methods for a given dilution of virus demonstrated a strong correlation ($r^2=0.99$). Foci of virus infected cells as revealed by the enzyme reaction could be counted either 4 days post-infection (p.i.) under low magnification (40X) microscopy, or 6 days p.i. by naked eye observation. Larger size of cell cuture plate, virus adsorption at $35^{\circ}C$, and 10% FBS in diluent appeared to be better conditions for the assay. Immunofocus assay will be an effective and dependable titration method for varicella-zoster virus and its live vaccine in place of the standard plaque assay in respect to accuracy, costs, and experimental convenience.

• 대한화학회지
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• 제13권1호
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• pp.49-55
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• 1969

螢光X線을 利用하여 珪酸鹽鑛物中의 主成分인 $SiO_2$, $Al_2O_3$, $Fe_2O_3$, CaO, MgO 및 $K_2O$를 迅速히 分析할 目的으로 試料의 處理 測定 및 各條件에 對하여 檢討하였다. 試料를 Lithium Tetraborate로 용융하여 300Mesh 以上의 微粉末로 한後 40,000Lb의 壓力으로 成型하여 Tungsten과 Chromium 對陰極의 X-線管과 LiF, EDDT, ADP의 分光結晶을 使用하여 測定하였다. 各成分에 對한 檢量曲線은 Matrix Effect를 고려하여 N.B.S 및 International Rock Standard를 選定 使用하였고 Lanthanum Oxide 및 Binder로서 Borie Acid를 첨가하여 얻었다. 各成分에 對하여 本法의 再現性 및 誤差를 檢討하기를 爲하여 I.R.S T-1을 使用하여 測定한 結果 0.47($SiO_2$), 0.85($Al_2O_3$), 0.05($Fe_2O_3$), 0.07(caO), 0.02($K_2O$), 0.13(MgO)의 標準偏差를 얻었다. 또한 化學分析植에 對한 偏差를 求하고져 Clay, Kaoline, Alunite, Wallastonite 및 Zeolite 等의 珪酸鹽鑛物을 選定하여 化學分析 및 本法에 依한 分析結果를 비교하였다.

• 대한수의학회지
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• 제8권2호
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• pp.125-146
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• 1968

Throughout the studies the following experimental results were summarized. 1. It was impossible to infect and kill the mice, weighing 10 to 12 gm, by inoculating 0.2ml of virulent Cl. chauvoei, diluted 1 to 10 with physiological saline, via subcutaneous, intramuscular, intraperitoneal or intraveonus, route. 2. The mice which were inoculated in brain with 0.03ml of Cl. chauvoei diluted 1 : 5120 with physiological saline were resulted in all death after infection, but not in case of attenuated strain even in dilution of one to five. 3. Virulent Cl. chauvoei were diluted with each of those of whole blood, erythrocytes and serum of horse, calf, swine, sheep, rabbit, guinea pig, chicken and duck, human plasma and 2% CaCl solution, and inoculated subcutaneously 0.25 to 0.5ml in mice, weighing 12 to 15gm. It was resulted in significant increase in virulence as comparing with the case of physiological saline solution except when horse and pig sera were used. Such a phenomena were not seen in attenuated strain. 4. Virulence of virulent Cl. Chauvoei could be increased significantly in rat, as the procedures used in mice, by suspending in whole blood, erythrocytes, serum, or plasma of various animals, or 2% $CaCl_2$ solution and by inoculating subcutaneously 0.5 to 10ml in rat, weighing 30 to 60 gm, as compared with those of control group which used physiological saline solutionos diluent. 5. Mice resisted 100 and 80 percent against challenge of $10^3$ and $10^4$ M.L.D.. respectively, 24 hours after inoculation of 0.5ml black leg antiserum. 6. Immune response to the black leg living vaccine in mice could be obtained more favorably in the group of respected vaccination rather than those of single inoculation and the most profitable inoculm size of the vacine was 0.5 to 1.0ml. 7. Challenge for the immunized mice could be carried out effectively 3 weeks after first vaccination. 8. Satisfactory results could be obtained by inoculating subcutaneously for the immunization and intracerebrally or subcutaneously for the challenge. 9. Mice which were inoculated with 0.5ml of black leg living vaccine via subtaneucously two times at seven days interval and 21 days after first inoculation and challenged with 5 and 10 M.L.D. of virulent strain, resited 100 and 70 to 80 percent respectively. Same results were obtainable in black leg killed vaccine as the procedures used in living vaccine. 10. There were significantly different resistances against the definite challenge does between the mice groups which were immnuized with the living vaccine diluted five or 10 times and the undiluted. 11. For the biological assay of black leg living vaccine and antiserum, satisfactory results could be obtained using mice.

• Restorative Dentistry and Endodontics
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• 제33권1호
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• pp.1-8
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• 2008

본 연구는 공초점 현미경을 이용하여 새로운 단량체와 filler의 크기, 연마방법이 실험용 복합레진의 표면조도에 미치는 영향을 연구하였다. 단점이 많은 희석재인 TEGDMA의 사용을 줄이기 위해, Bis-GMA의 유도체로서 중합수축이 적고 점도가 낮은 새로운 단량체인 methoxlyated Bis-GMA (Bis-M-CMA)를 첨가하고 다른 크기의 filer를 갖는 2종의 실험용 복합레진과 TEGDMA를 함유한 1종의 실험용 복합레진을 제작하였다. EX1; 실험용 복합레진 1 (Bis-M-GMA/TEGDMA = 95/5 wt%, 40 nm 나노필러 함유), EX2; 실험용 복합레진 2 (Bis-M-GMA/TEGDMA = 95/5wt%, 20 nm 나노필러 함유), EX3; 실험용 복합레진 3 (Bis-GMA/TEGDMA = 70/30 wt%, 40 nm 나노필러 함유). 테프론 몰드를 이용하여 지름 6 mm 두께 2 mm의 시편을 각 실험용 복합레진과 Filtek Z250으로 9개씩 만들고 3군으로 분류하였다. Mylar strip 군은 연마를 하지 않았고, Sof-lex군은 #1000 SiC paper로 연마한 뒤 501-lex disc로 연마하였다. Diapolisher 군은 #1000 SiC paper로 연마한 뒤 DiaPolisher polishing point로 연마하였다. 공초점 현미경을 이용하여 각 시편당 7군데에서 Rq (Root mean square roughness), Rv (Valley roughness), Rp (Peak roughness), Rc (2D Roughness), Sc (3D Roughness) 값을 측정하였고, Two-way ANOVA와 Tukey multiple comparisons test로 유의수준 0.05로 통계처리 하였다. 복합레진의 종류 (p < 0.001), 연마 방법 (p < 0.001)은 각각 모두 표면조도 값에 영향을 미치며, 복합레진의 종류와 연마 방법 간에는 교호 작용이 관찰되었다 (p < 0.001). 복합레진의 종류에 따른 표면조도는 EX2가 가장 거친 표면을 보였고, EX3이 가장 평활한 면을 형성하였으며 (p < 0.05). 연마 방법에서는 연마하지 않은 Mylar strip 군이 가장 평활한 면을 형성하였다 (p < 0.05). 본 연구 결과를 종합하여보면 연마하지 않고 Mylar strip하에서 복합레진이 중합된 경우 가장 낮은 표면조도와 평활한 표면을 보였으며, 새로운 레진 단량체인 Bis-M-GMA를 함유한 복합레진이 수복물의 표면조도 측면에서는 필러 크기에 관계없이 기존의 Bis-GMA/TEGDMA를 기질단량체로 사용하는 복합레진에 비교하여 우수하지 못한 것을 확인하였다.

• 한국식품저장유통학회지
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• 제23권6호
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• pp.797-803
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• 2016

본 연구에서는 전분 및 단백질 분해력이 우수한 토착 발효종균 Aspergillus luchuensis 74-5 및 Aspergillus oryzae 75-2로 제조한 고체종국의 품질 특성을 조사하였다. 액체종국 접종량 5%와 10% 접종하였을 때, pH는 각각 5.78 및 3.85 이하로, 적정산도는 2.12와 8.54 이상, 아미노산도는 1.15 및 2.66 이상으로 균주에 따라 차이를 보였다. 효소활성의 변화는 발효종균에 따라 증감 패턴이 특징적으로 나타났고, 액국 접종량에 따라 A. luchuensis 74-5는 접종량이 증가할수록 ${\alpha}-amylase$와 glucoamylase 활성은 증가하나 acidic protease활성은 감소하였고, A. oryzae 75-2는 5% 접종하였을 때 모든 효소활성이 가장 높게 나타났다. 발효온도는 저온보다 중온(35, $40^{\circ}C$)에서 효소활성이 우수한 것으로 나타났고, 발효시간은 종균에 따라 차이는 있지만 각각 144시간과 120시간일 때 효소활성이 높은 것으로 나타났다. 발효조건에 따른 고체종국의 포자수는 약 $2.0{\times}10^7$, 세균의 오염은 약 $3.0{\times}10^3$으로 나타났으며, 세균에 의한 오염도 저감화 및 효소활성을 유지하기 위하여, 구연산, 종국의 건조법 및 부형제 등의 추가적인 연구가 필요하다.