• Current Optics and Photonics
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• 제4권3호
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• pp.247-252
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• 2020

Important determinants for selecting outdoor lighting are the color-rendering index (CRI) and scotopic-to-photopic (S/P) ratio of the lighting units. The higher the S/P ratio, the better energy savings and visual performance. In this study, CCT-tunable LED lighting units were optimized and fabricated by spectral combination of red, green, blue, and yellow LEDs. The measured results for RGB LEDs provided S/P ratios of 1.55~2.58 and those of RGBY LEDs gave 1.46~2.46 to the correlated color temperatures (CCTs) ranging from 2700 K to 6500 K, with CRI values of over 80 at the same time.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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• pp.283-289
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• 1996

In this paper, the mix design of the super flowing concrete is described with respcet to basic concept, confined water ratio($\beta_p$), volume ratio of water-binder(w/b), volume ratio of fine aggregates($S_r$) and coarse aggregates($G_v$). The primary purposes of this study are to evaluate the effects of cementitious materials(fly ash, slag cement, portland cement), mixing factors ($\beta_p$, w/b, $S_r$, $G_v$)., and to propose the mix design method of the super flowing concrete. As results of this study, confined water ratio($\beta_p$) of cementitious materials is very high (0.99~1.1), and then the ranges of the optimum mixing factors to be satisfied with the super flowing concrete are $S_r$ 47$\ell$ 2%, $G_v$ 52$\ell$ 1%.

• Journal of Nutrition and Health
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• 제28권2호
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• pp.95-106
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• 1995

The effects of various n-6/n-3 ratios(about 2, 4, 6, 8) of dietary fatty acids on various lipid levels and prostaglandin production were studied at the constant P/S ratio (1.5-1.6) in young (5 weeks old) and adult(8 months old) Sprague-Dawley rats using palm oil, safflower oil and sardine oil. The concentration of serum cholesterol tended to increase with the increasing n-6/n-3 ratio. The tendency of HDL-cholesterol levels was similar to serum cholesterol levels. These were not apparent differences between young and adults rats. Serum triglyceride levels increased according to increasing n-6/n-3 ratio in young rats. These were generally high in the adult rats compared with the young rats. Though liver cholesterol level tended to increase according to the increasing n-6/n-3 ratio in the young rats. The liver triglyceride level did not change according to the n-6/n-3 ratio. However, these levels were apparently higher in the adult than in the young rats. The fatty acid compositions of phosphatidylcholine(PC) were similar in serum and liver. The arachidonate/linoleate ratios in tissue PC were influenced by the n-6/n-3 ratio. They tended to be lower in the adult rats compared with the young rats. It was suggested that the activity of $\Delta$6-desturase was decreased by aging. Production of platelet thromboxane A2(TXA2)and aortic prostacyclin(PGI2) was not apparently influenced with n-6/n-3 ratio. Whereas the ratio of TXA2/PGI2 was the lowest value at 3.8 of n-6/n-3 ratio, expecially in the young rats. Thus this ratio seemed to be a desirable level to protect atherosclerosis. These results indicate that the lipid level and prostaglandin production were influenced not only by n-6/n-3 ratio(under constant P/S ratio) but by aging, particulary triglycerde level and arachidonic/linoleic acid ratio.

• 자원환경지질
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• 제18권2호
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• pp.151-157
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• 1985

Events detected by the KIER microearthquake network operated in the Southern Part of Korea for 265 days in 1982~1984 were reviewed, and some of them were identified to be a dynamite explosion from several construction sites. The purpose of the present work is to determine the crustal structure of the Southern Korea using the time-destance data obtained from such explosion seismic records. The time·distance data can be well explained by a crustal model composed of four horizontal layers of which thickness, p and s-wave velocity ($V_p$ and $V_s$) are characterized as follows. 1st layer (surface) ; 0~2km, $V_p=5.5km/sec$, $V_s=3.3km/sec$ 2nd layer (upper crust) ; 2~15km, $V_p=6.0km/sec$, $V_s=3.5km/sec$ 3rd layer (lower crust) ; 15~29km, $V_p=6.6km/sec$, $V_s=3.7km/sec$ 4th layer (upper mantle) ; 29km~ , $V_p=7.7km/sec$, $V_s=4.3km/sec$ The relatively shallow crust·mantle boundary and low $P_n$ velocity compared with the mean values for stable intraplate region are noteworthy. Supposedely, it is responsible for the high heat flow in the South-eastern Korea or an anomalous subterranean mantle. The mean $V_p/V_s$ ratio calculated from the relation between p-wave arrival and s-p arrival times appears to be 1.735 which is nearly equivalent to the elastic medium of ${\lambda}={\mu}$. However, the ratio tends to be slightly larger with the depth. The ratio is rather high compared with that of the adjacent Japanese Island, and the fact suggests that the underlying crust and upper mantle in this region are more ductile and hence the earthquake occurrences are apt to be interrupted. As an alternative curstal model, a seismic velocity structure in which velocities are successively increased with the depth is also proposed by the inversion of the time·distance data. With the velocity profile, it is possible to calculate a travel time table which is appropriate to determine the earthquake parameters for the local events.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.387-388
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• 2006

The influence of porosity (P) on Young's modulus (E) and Poisson's ratio $(\upsilon)$ of sintered steels produced from four types of steel powders was investigated. The values of E and $(\upsilon)$ depend mainly on the value of P, and those were a little affected by alloying elements. The relationships between E, $(\upsilon)$, and P were described as following equations: $E\;=\;E_0{\cdot}(1\;-\;k_E{\cdot}P)^2$ and $\upsilon\;=\;({\upsilon}_0\;-\;\upsilon_{sub}){\cdot}(1\;-\;k_{\upsilon}{\cdot}P)2+\upsilon_{sub}$, where subscript 0 means P = 0, and $k_E,\;k_{\upsilon}$ and ${\upsilon}_{sub}$ are empirical constants. These approximate equations showed good agreement with empirical results.

• 한국동물위생학회지
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• 제29권1호
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• pp.9-18
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• 2006

The ELISA titers to avian pneumovirus (APV) and avian reovirus (ARV) were surveyed to sera of 38 breeder farms (78 blocks, 1,560 hens) in Jeonbuk province during February to October, 2005. In APV, the positive ELISA were detected 36 (94.7%) breeders, 71 (91.0%) blocks, 1,057 (67.8%) hens, and their S/P ratio was 1.940. Regionally, the positivity of 24 breeders farms in the Jeonju, Jeongeup, Namwon, and Jangsu were noted as 100%, whereas 85.7% in Iksan. The positivity to species such as Cobb (20), Ross (13) and Hanhyup-3 (5), all of the breeding farms were detected as positive, 40 (86.9%), 17 (94.4%) and 14 (100.0%) in blocks, 553 (60.1%), 285 (79.2%) and 219 (78.2%) in hens, and their mean S/P ratio were 1.677, 1.769 and 2.254, respectively. The positivity of the breeders vaccinated with ARV, all of the 9 breeder farms (38 blocks) were noted as 100%, but 627 (82.5%) in hens, and its mean S/P ratio was 1.273. Whereas nonvaccinated with ARV were 28 (96.5%) in breeders farms, 38 (95.0%) in blocks, 660 (82.5%) in hens, and the mean S/P ratio was 1.612. In species which were vaccinated with ARV, 11 breeder farms (38 blocks) were noted as 100%, but 82.5% in hens, and their mean S/P ratio were 1.315. Whereas in nonvaccinated with ARV, 25 (92.6%) in farms, 38 (95.0%) in blocks and 660 (82.5%) in hens were positive, and their mean S/P ratio was 1.532.

• Journal of the Korean Wood Science and Technology
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• 제28권3호
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• pp.1-8
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• 2000

본 연구는 미이용 자원인 소경목(小經木) 조생수(早生樹) 등의 저질원료로부터 고성능을 지니는 구조용 보드를 제조하는 기술을 개발하는 것을 목적으로 하여 할렬 스트랜드 (S)/파티클(P) 복합체의 층구조와 S와 P의 혼합비율을 바꾼 단면구성에 따른 기초적 물성을 검토했다. 그 결과 스트랜드층을 포함하고 있는 SP 복합체의 경우, 전체적으로 휨성능(MOR, MOE)이 매우 높았다. 또 S단층 보드는 현저한 이방성을 나타내었지만 층구조가 PB에 가까워질수록 이방성은 감소하여, 7층 구조의 복합체는 이방성이 적었으며 특히 SP7은 직교방향도 휨강도가 높았다. 습윤시 휨강도 성능도 같은 경향을 나타내었다. 박리강도(IB)는 PB가 가장 높았고, 스트랜드층을 가진 복합체는 거의 같은 값을 나타내었다. 두께팽창율(TS) 은 PB가 가장 적은 값을 나타내었으며, 표층이 P층인 구조가 S표층구조보다 적은 경향을 나타내었다. 복합체의 표면특성은 표층 엘리먼트의 영향을 받아, 적고 미세한 엘리먼트인 P표층의 복합체가 크고 두꺼운 S표층 복합체보다 양호하였다. S와 P의 혼합비율의 영향은, SP비(比)를 증가시켜도 강도물성(MOR, MOE, IB)은 향상되지 않으며, 오히려 저하되는 것도 있었다. 두께팽창율(TS)은 SP 비(比) 1:1 이상의 복합체에서는 S만으로 제조한 보드와 같은 정도의 값을 나타내었다.

• Journal of Nutrition and Health
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• 제28권10호
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• pp.1004-1014
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• 1995

Effect of age and dietary fatty acid composition on immune responses were investigated in Sprague-Dawley male rets. The animals weighing 88.6$\pm$2.2g were fed 10% dietary fat (W/W, 20% of calorie) with P/S ratio of 0.5, 1 and 2, and in each group, there were three different levels of n-6/n-3 fatty acid ratio; 2, 4 and 8(3$\times$3). The experimental periods were 1 month, 6 months and 12 months. The results of this study were; 1) Weights of thymus and spleen were significantly reduced with increasing age, moreover thymus weights were reduced with increasing the degree of unsaturation in dietarty fatty acid at 12 month. 2) The proportion of splenic lymphocyte in the total T-cell was increased with increased with age. The proportion of helper T-cell was not changed, while the proportion of suppressor T-cell was decreased. Thus at 12 month, the ratio of helpe $r^pressor T-cell was appeared to increase significantly, and showed the tendency to increase by consuming the low amount of dieraty n-3 fatty acid. 3) Proliferation stimulated by Con A or PWM reduced significantly at 12 month in which are high in dietary P/S ratio, representing the similar pattern with decrease in thymus weight. 4) Natural killer cell activities were shown significantly higher at 1 month than those at 6 month or 12 month.th.

• 터널과지하공간
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• 제23권3호
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• pp.212-218
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• 2013

풍화된 응회암 시험편을 모사하기 위하여 최고 예열온도를 200, 400, 600($^{\circ}C$)로 한 예열시험편을 제작하였다. 각 예열시험편에 대한 실내시험을 통해 비중, 흡수율, 탄성파속도, 일축압축강도, 압열인장강도, 탄성계수, 포아송비, 슬레이크 내구성 지수를 측정하였다. 암석에 열을 가하는 경우 물성의 열화가 발생하는 것으로 나타났으나 예외적으로 슬레이크 내구성 지수는 별로 영향을 받지 않는 것으로 평가되었다. P-파 속도와 일축압축강도, 압열인장강도, 탄성계수, 흡수율 간에는 상당한 상관성이 있는 것으로 해석되었으며, P-파 속도를 알면 일축압축강도, 압열인장강도, 탄성계수, 흡수율을 추정할 수 있는 회귀식을 도출하였다.

• Journal of the Korean Wood Science and Technology
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• 제20권1호
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• pp.60-71
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• 1992

To investigate the delignification behaviour in solvolysis pulping process, Populus alba ${\times}$ glandulosa H. and Pinus Kuraiensis S. et Z. were cooked with p-cresol and vater solvent(2:8, 5:5, 8:2 v/v) at $175^{\circ}C$ for 9 cooking time levels(20, 40, 60, 80, 100, 120, 140, 160, 180, min). Pulp yield, residual lignin content, de lignification rate, decarborhydration rate were determined. Delignification behaviours were analyzed by TEM. 1. The p-cresol-water solvent cooking of P. alba ${\times}$ glandulosa showed good delignification at the solvent system which the mixture ratio of p-cresol and water were 2:8(v/v), while the cooking of P. koraiensis with the p-cresol and water mixture ratio of 5:5 was no good. 2. P. alba ${\times}$ glandulosa showed three step-delignification phenomena at the solvent system which the mixture ratio of p-cresol and water were 2:8(v/v) anti 5:5(v/v). But P. koraiensis showed a first order delignification reaction at the same mixture ratio of p-cresol and water solvent system. 3. In TEM micrograph obtained for the solvent system which the mixture ratio of p-cresol and water was 5:5(v/v), the partial delignification of the cell corner of P. alba ${\times}$ glandulosa and P. koraiensis were observed at 60min. of cooking time. Complete delignification at the cell corner of P. alba ${\times}$ glandulosa was observed at 160min. and that of P. koraiensis was observed of 180min. of cooking time. 4. In optical microscopic observation, fiber separation of P. alba ${\times}$ glandulosa occured at 120min. and that of P. koraiensis began at 140min. of cooking time. 5. At the solvent system which the mixture ratio of p-cresol and water was 5:5(v/v), middle layer on secondary wall($S_2$) and cell corner of P. alba ${\times}$ glandulosa were more selectively delignified than primary wall(P) and outer layer on secondary wall($S_1$). However P. koraiensis did not showed any difference in delignification between cell wall layers and cell corner.