• 산업기술연구
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• 제7권
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• pp.9-14
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• 1987

The maximum specific gravity of asphaltic concrete can be calculated based on the effective specific gravity of aggregates and the specific gravity of asphalt cement. The maximum specific gravity is sometimes obtained based on the apparent specific gravity of aggregates and specific gravity of asphalt concrete. However, the apparent specific gravity is in general greater than the effective specific gravity for most aggregates. This study showed, by comparing the results obtained based on two specific gravities, that application of the apparent specific gravity instead of the effective specific gravity resulted in discrepancies in the calculated values of effective asphalt content, air void and maximum density.

• 한국식품조리과학회지
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• 제15권4호
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• pp.377-381
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• 1999

This study was designed to observe the effect of the amount of egg and the specific gravity on the quality of sponge cake. There was a little difference of the moisture content by the specific gravity when the amount of egg was same. However, as the amount of egg was increased at the same specific gravity, the moisture content and baking loss was significantly increased(p<0.05). At 100% of egg amount, the largest specific loaf volume was gained at 0.55 of specific gravity, in the same way 150% at 0.45, 200% at 0.35, 250% at 0.45, The hardness of sponge cake was increased as the specific gravity was increased at the same amount of egg(p<0.05). The specific gravity which the lowest hardness was gained was 0.55 with 100% of the amount of egg, in th same way 0.45 with 150%, 0.35 with 200%. As the period of storage was longer, the increase of hardness was increased as the specific gravity went up at the same amount of egg(p<0.05). Therefore, in the case of sugar content 166%, the specific gravity with maximum specific loaf volume and minimum hardness was gained 0.55 at the amount of egg 100%, 0.45 at 150%, 0.35 at 200% and 0.35 at 250%.

• 한국작물학회지
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• 제53권4호
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• pp.434-439
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• 2008

The amount of salt to make seed sorting solution of the specific gravity of 1.13 was reconsidered and determined as 3.8 kg salt in 18 L water, which is lower amount than currently used. Five rice cultivars were examined. Percent germination and seedling emergence were not similar. Seedling emergence rate of Japonica varieties, Nampyungbyeo and Daerypbyeo-1 were 87% and 95% under specific gravity of 1.13, respectively. Seedling emergence rate of Tongil type variety, Dasanbyeo was as high as 67% in specific gravity of 1.06. Seedling emergence rate of waxy rice, Hwasunchalbyeo and Aranghangchalbyeo were examined. Seedling emergence rate was 94% in both cultivars in specific gravity of 1.04. Seedling emergence rate was same in specific gravity of 1.08 which is generally used for selecting seed currently. Early growth (plant height, leaf number, and dry weight) were not significantly different by specific gravity within species. In all cultivars except waxy rice, highest seedling emergence rate was observed in specific gravity of 1.13 which is currently used for selection and decreased as specific gravity is lowed. However, considering total amount of seeds in each group of specific gravity, amount of seed in lower specific gravity group is relatively small and total seedling emergence rate within variety dose not show big difference. However, if seeds with low speicific gravity are produced due to the bad grain filling condition and consequently total seed content of low specific gravity increases, results will be differnt. Reduction in total growth and yield could occur. It will be important to comply with the seed sorting criterion of 1.13 for Japonica, 1.06 for Tongil, and 1.04 for waxy rice variety to ensure the maximum rice growth and yield.

• Ocean and Polar Research
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• 제39권4호
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• pp.257-267
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• 2017

Although Pacific mackerel (Scomber japonicus) is an important commercial species in Korea, its recruitment mechanism remains largely unknown. Diel vertical positioning of larvae in the water column, which is affected by their specific gravity and the surrounding water density, may help to provide an understanding on recruitment success through predator avoidance and prey availability. The specific gravity measurement on Pacific mackerel eggs and larvae would seem to be essential information necessary to learn about the transport process from spawning to nursery grounds, and consequently the recruitment success. Eggs were artificially fertilized, and larvae were fed with rotifer when their mouths opened 3-4 days after hatching. We conducted the experiment using a density gradient water column to measure the ontogenetic changes in specific gravity from fertilization to 10 days after hatching. Egg specific gravity was stable during most of the embryonic period, but a sudden increase to $1.0249g\;cm^{-3}$ happened just before hatching. However, the specific gravity of newly hatched larvae was much lighter ($1.0195g\;cm^{-3}$), and specific gravity tended to increase continuously after hatching. Comparison of specific gravity with seawater density reveals that eggs and newly hatched larvae can float in the surface layer of the ocean. For the later period of the experiment, the specific gravity showed a cyclic diel pattern: the highest in the evening while the lowest at dawn. The fullness of larval stomach may be responsible for the observed differences in specific gravity, because stomach fullness was lower (40-60%) at midnight, and higher (80-85%) in evening. The diel pattern of specific gravity might provide clues regarding how larvae match the diel vertical migration of prey organisms.

• 한국수산과학회지
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• 제51권3호
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• pp.332-337
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• 2018

The Pacific cod Gadus macrocepahlus, lays demersal eggs and the hatching larvae rise toward the surface layer of the ocean to feed. The change in the specific gravity of eggs and larvae was investigated to examine their vertical distribution and movement in the water column. The specific gravities of fertilized eggs and various size classes of larvae were measured using a density gradient apparatus. In total, the instantaneous specific gravity of 146 eggs and 225 larvae were measured. To prevent any disturbance in the gradient water column due to larval movement, 0.004% MS222 was used for anesthesia. Due to their high specific gravity, eggs spawned were deposited over the sea-bed of the spawning ground. The specific gravity of hatching larvae decreased abruptly. However, Pacific cod larvae still had a comparatively high specific gravity at hatching ($1.03655{\pm}0.00146g/cm3$, n=4, mean SL=3.62 mm) and their specific gravities tended to decrease as they grew. The specific gravity stabilized 6 days after hatching ($1.02590{\pm}0.00212g/cm3$, n=15, mean SL=4.67 mm) and the cod larvae were eventually able to float in the water column.

• Journal of the Korean Wood Science and Technology
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• 제34권2호
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• pp.1-9
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• 2006

The structural wooden members of the ancient building are deteriorated by fungi and termite over time. The deteriorate of the members causes the decrease of the specific gravity and the strength of it, so the stability of the building is threatened. Therefore, in this study, the evaluation of the specific gravity, which is correlated with the strength of the wood, was conducted in the post member using Nondestructive Evaluation (NDE) - Drilling Resistance Test (DRT). For the purpose of it, the specific gravity and drilling resistance of small specimens was measured to obtain the correlation between the specific gravity and the drilling resistance. And then, the drilling resistance test of the post members, which were expected to have the deteriorated parts, was performed. Consequently, the correlation between the specific gravity and the drilling resistance was very high ($R^2=0.89$) and the distributions of the specific gravity were evaluated for the each member. Also, the results were verified by the visual inspection of the cross section of it. Especially, the various variations of the wood member such as the deteriorated parts with termite or fungi and the crack could be detected exactly but the knot couldn't because the drill could pass by or could not penetrate the knot.

• 한국잠사곤충학회지
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• 제20권2호
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• pp.6-9
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• 1978

잠 103$\times$잠 104 와 그 역교, 잠107$\times$잠108 및 그 역교를 공시하여 6개 업자의 잠종비중별 부화율 및 실용부화율 시험에서 얻은 결과는 1. 난비중을 세분하여 부화율 실용부화율을 보면 경비중에 비하여 중비중 및 중비중의 난이 부화율 및 실용부화율이 높았다. 2. 일모체는 중모체에 비하여 경비중 및 중비중난에서 부화률이 높았고 실용부화율은 경비중난에서만 높았다. 3. 중모체는 비중별 실용부화율 및 부화율의 차이가 컸으며 이에 비하여 일모체는 부화율에는 차이가 없으나 실용부화율에서 비중별 차이를 인정할 수 있었다. 4. 제조업자별 중비중난의 부화율 및 실용부화율의 차이는 없으나 경비중, 중비중난에서는 현저한 차이를 나타내었다.

• 한국가구학회지
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• 제10권1호
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• pp.57-63
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• 1999

This study was carried out to analyze the relationship between basic physical properties and acoustical characteristics of imported violin wood and to offer the information on raw material procurement and incoming-material quality control to domestic violin makers which have purchased most raw materials from European exporting countries at high expense. Equilibrium moisture content of European spruce with lower specific gravity after the prolonged storage was rather higher than that of European maple with higher specific gravity. The specific gravity of spruce increased with decreasing annual ring width, however, that of narrower annual ring. Increasement in specific gravity enhanced the dynamic Young's modulus of both wood species, but influenced the vibration energy loss by internal friction differently between two species. For dynamic MOE, qurater-sawn spruce was higher than the flat-sawn, but maple showed the reverse directional characteristics. Consequently, it would be well for violin makers to establish the standard for materials and quality control system to assure the quality of their violin products.

• KSBB Journal
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• 제22권5호
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• pp.366-369
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• 2007

본 연구에서는 식물세포배양으로부터 회수한 식물세포, 즉 biomass로부터 항암제 paclitaxel를 정제하기 위한 크로마토그래피 공정에서 컬럼을 통하여 용리되는 eluent의 비중 (specific gravity) 조절에 의한 eluent 재사용 방법을 개발하였다. 크로마토그래피 조업 전에 eluent (methanol/water = 70/30, v/v)의 비중을 측정한 결과 0.853을 얻었다. 컬럼으로부터 분취한 용액을 증발 건조하여 건조된 제품과 증발된 용액인 eluent를 각각 회수하였다. HPLC 분석을 통하여 증발/회수된 eluent에 불순물이 포함되어 있지 않음을 확인하고, 회수된 eluent의 비중을 측정하여 비중이 0.853에서 벗어났을 경우에는 메탄올 또는 물을 첨가하여 eluent의 비중을 0.853으로 조정하여 eluent로 재사용하였다. 회수된 eluent를 재사용하여 크로마토그래피 정제를 실시한 결과, 고순도 ($\sim$95%), 고수율 ($\sim$86%)의 paclitaxel을 얻을 수 있었다. 이는 eluent를 재사용하지 않을 경우, 즉 재사용 전과 동일한 수준의 결과로 비중 조절에 의한 eluent의 재사용이 성공적임을 알 수 있었다.

• Journal of the Korean Wood Science and Technology
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• 제48권4호
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• pp.458-471
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• 2020

Effect of pre-treatment and compression ratio on specific gravity (SG) and dimensional stability improvement of three lesser-used wood species from natural forest area of North Kalimantan Province, Indonesia had been investigated. Hot soaking at 80℃ for 3 hours within 2 and 5% of boron solution was applied as pre-treatment, while compression ratio applied was 20 and 40% from the initial thickness. Densification was conducted using hot pressing machine at 30 kg/㎠ of pressure and 160℃ of temperature for 15 minutes. Specific gravity was measured gravimetrically, while dimensional stability was evaluated through thickness swelling and water absorption as the indicator. Results show that SG of densified wood was influenced by wood species and compression ratio, but not by pre-treatment applied; while dimensional stability was influenced by wood species, compression ratio, and pre-treatment. Specific gravity and water absorption of densified wood was improved significantly. Specific gravity increased 28.86-63.03%, while water absorption decreased 12.80-15.89%. Thickness swelling of 20% densified wood was lower than that of 40% densified wood.