• Advances in concrete construction
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• 제7권2호
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• pp.87-96
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• 2019

Self-compacting concretes (SCC) are highly fluid concrete which can flow without any vibration. Their composition requires a large quantity of fines to limit the risk of bleeding and segregation. The use of crushed sand rich in limestone fines could be an adequate solution for both economic and environmental reasons. This paper investigates the influence of quarry limestone fines from manufactured crushed sand on rheological, mechanical and durability properties of SCC. For this purpose, five mixtures of SCC with different limestone fines content as substitution of crushed sand (0, 5, 10, 15 and 20%) were prepared at constant water-to-cement ratio of 0.40 and $490kg/m^3$ of cement content. Fresh SCC mixtures were tested by slump flow test, V-funnel flow time test, L-box height ratio, segregation resistance and rheological test using a rheometer. Compressive and flexural strengths of SCC mixtures were evaluated at 28 days. Regarding durability properties, total porosity, capillary water absorption and chloride-ion migration were studied at 180 days. For the two test modes in fresh state, the results indicated compatibility between slump flow/yield stress (${\tau}_0$) and V-funnel flow time/plastic viscosity (${\mu}$). Increasing the substitution level of limestone fines in SCC mixtures, contributes to the decrease of the slump flow and the yield stress. All SCC mixtures investigated achieved adequate filling, adequate passing ability and exhibit no segregation. Moreover, the inclusion of limestone fines as crushed sand substitution reduces the capillary water absorption, chloride-ion migration and consequently enhances the durability performance.

• 한국작물학회지
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• 제33권2호
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• pp.157-160
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• 1988

본 연구는 호프의 수령, 재배지 표고, 생산년도에 따른 생구화 수량의 변화를 구명하여 재배면적 확대, 적지선정 및 수량 예측의 기초자료로 이용하고자 호프 주산지인 강원도 횡성에서 756 농가의 생구화 수량을 중심으로 검토하였던 바 다음과 같은 결과를 얻었다. 1. 호프의 수령별 10a당 평균 생구화 수량은 1년생 181.0kg. 2년생 516.0kg, 3년생 670.0kg, 4년생 726.4kg, 5년생 761.0kg 이었다. 2. 호프의 수령간 생구화 수량은 1, 2, 3, 4 년생에서 각각 고도의 유의한 수량차가 있었으나 4년생과 5년생 이상과는 수량차가 인정되지 않아 호프의 수량성은 4년생 이상이 되어야 충분히 발휘될 수 있었다. 3. 4년생 이상 호프의 재배지 표고별 수량차는 인정되지 않았으나 재배 년도별 평균 수량은 통계적 유의차가 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제13권9호
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• pp.1329-1336
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• 2000

Two experiments were carried out to investigate the effect of Murrah buffalo cows pulling sledges under field conditions on milk production and milk composition. In Exp. 1, 24 buffaloes in the fourth month of lactation were used. They were allotted to four treatments according to a $2{\times}2$ factorial arrangement: work or no work, and with or without urea-molasses cake supplementation (700 g/animal/day). Feeds consisted of 20 kg fresh elephant grass (18% DM), 2 kg rice bran per day and rice straw ad lib. The animals worked in pairs three hours per day (work done: $3464{\pm}786kJ/d$) five days a week for three months. Three teams worked in the morning and the others worked in the afternoon in the same day. The following day the working times were switched. In Exp. 2, 16 lactating Murrah buffalo cows in the sixth month of lactation were allotted to two groups (work and no work). They were fed with fresh ruzi grass (Brachiaria ruziziensis) ad lib. supplemented with 2 kg rice bran and 700 g urea-molasses cake. The working regime was similar to that of the first experiment (work done: $3753{\pm}879kJ/d$) and they worked for two months. In the first experiment, there was a small but significant drop (p<0.05) in milk yield from 3.5 to 3.0 kg/day due to work, but there was no supplementation effect. The working buffaloes lost 5.2 kg whereas the non-working animals gained 9.7 kg during the three months (p<0.05). Supplementation increased live weight by 9.9 kg as compared to -5.4 kg for those not supplemented (p<0.05). Milk composition was not affected by the treatments. In the second experiment, daily milk production was similar for both treatments and approximately 3 kg. No significant differences were found in milk composition or in live weight changes for working and non-working groups, respectively. It was concluded that work may cause a reduction in milk yield and a loss of live weight on a poor rice straw diet but that an appropriate supplementation can alleviate this situation.

• 한국초지조사료학회지
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• 제29권1호
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• pp.19-24
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• 2009

초고는 크림손 클로버에 비하여 헤어리 베치가 높았으며, 희토 1회 처리시 크림손 클로버는 가장 낮았고, 헤어리 베치는 가장 좋아 상반된 결과를 보였다. 크림손 클로버와 헤어리베치의 평균 건물율은 각각 20.3%와 18.1%로 크림손 클로버의 건물율이 높았으며 희토 처리에 의한 건물을 차이는 없었다. 생초 수량은 크림손 클로버에 비하여 헤어리 베치가 많았으나 건물 수량은 생초 수량과 반대로 크림손 클로버가 많았으며 유의적인 차이는 없었다. 크림손 클로버와 헤어리 베치의 생초 수량과 건물 수량은 두 초종 모두 희토 1회 처리가 가장 높았으나 유의적인 차이는 없었다. 사료가치는 크림손 클로버보다 헤어리 베치가 좋았으며, NDF와 ADF는 희토 1회 처리가 낮은 경향이었으나 조단백질과 소화율은 처리간에 뚜렷한 경향을 보이지 않았다. 따라서 본 연구는 크림손 클로버와 헤어리 베치가 희토에 반응하지 않았으며, 처리 횟수간에도 영향이 없었다.

• 원예과학기술지
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• 제34권3호
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• pp.405-413
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• 2016

Quinoa (Chenopodium quinoa Willd.) is a plant native to the Andean region that has become increasing popular as a food source due to its high nutritional content. This study determined the optimal photoperiod, light intensity, and electrical conductivity (EC) of the nutrient solution for growth and yield of quinoa in a closed-type plant factory system. The photoperiod effects were first analyzed in a growth chamber using three different light cycles, 8/16, 14/10, and 16/8 hours (day/night). Further studies, performed in a closed-type plant factory system, evaluated nutrient solutions with EC (salinity) levels of 1.0, 2.0 or $3.0dS{\cdot}m^{-1}$. These experiments were assayed with two light intensities (120 and $143{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) under a 12/12 and 14/10 hours (day/night) photoperiod. The plants grown under the 16/8 hours photoperiod did not flower, suggesting that a long-day photoperiod delays flowering and that quinoa is a short-day plant. Under a 12/12 h photoperiod, the best shoot yield (both fresh and dry weights) was observed at an EC of $2.0dS{\cdot}m^{-1}$ and a photosynthetic photon flux density (PPFD) of $120{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. With a 14/10 h photoperiod, the shoot yield (both fresh and dry weights), plant height, leaf area, and light use efficiency were higher when grown with an EC of $2.0dS{\cdot}m^{-1}$ and a PPFD of $143{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Overall, the optimal conditions for producing quinoa as a leafy vegetable, in a closed-type plant factory system, were a 16/8 h (day/night) photoperiod with an EC of $2.0dS{\cdot}m^{-1}$ and a PPFD of $143{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$.

• 한국약용작물학회지
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• 제8권2호
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• pp.89-93
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• 2000

절편씨마를 이용하여 마를 재배할 경우 토성에 따른 괴경의 형태적 특성과 수량성의 차이를 단마 품종 '마1호'와 장마 품종 '안동재래종'을 공시하여 검토한 결과를 요약하면 다음과 같다. 사토에서는 괴경의 길이가 짧고 분기의 발생이 많아 괴경의 모양이 좋지 않았다. 양토와 사양토에서는 사토에 비하여 분기 발생이 적어 괴경의 모양이 양호하였으며, 괴경의 생체수량은 단마가 $21{\sim}27%$, 장마가 각 6% 증수되었고 , 상마수량은 단마가 $45{\sim}55%$, 장마가 $20{\sim}22%$ 증수되었다. 식양토에서 단마는 괴경의 분지 발생이 다소 많았으며, 장마는 괴경의 굵기가 가늘고 만곡되어 모양이 좋지 않았다.

• 한국작물학회지
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• 제47권6호
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• pp.418-421
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• 2002

백하수오 근수량 증대를 위한 밀식 재배법을 확립하고자 직파와 육묘 이식으로 구분하여 파종하고 재식밀도를 달리하여 시험을 수행한 결과를 요약하면 다음과 같다. 1. 지상부 생육은 파종 방법 간에는 육묘 이식재배에서 양호하였으며, 재식밀도 간에는 밀식할수록 만장과 분지수는 길거나 많았으나, 엽장과 엽폭은 소식할수록 증가하는 경향이었으며, 개체당 엽수는 22주/$m^2$에서 가장 많았다. 2. 지하부 생육은 파종 방법 간에는 육묘 이식재배에서 양호하였고, 재식밀도 간에는 주당 지근수, 근장 및 근태는 소식할수록 많거나 길거나 굵었으나, 단위 면적당 지근수는 밀식할수록 증가하였다. 3. 생근수량은 직파 재배보다 육묘 이식재배에서 많았으며, 재식밀도 간에는 밀식할수록 많아 육묘 이식 17주/$m^2$(1,680 kkg/10a)에 비하여 27주/$m^2$(2,567 kg/10a)에서 53%증수되었다.

• 한국작물학회지
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• 제47권5호
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• pp.356-360
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• 2002

The seedlings of yacon (Polymnia sonchifolia Poeppig ＆ Endlicher), which were cuttings, plug seedling (PS), crown bud before sprouting (CBBS), crown bud after sprouting (CBAS), and divided seedling after budding (DSAB) were planted at 70$\times$50 cm planting distance on ridge; that was interow spacingintrarow spacing, and about 28,500$\pm$71 plants/ha. CBBS didn't need work and equipment to raise seedlings. PS and DSAB grew taller to 140.5 and 143.3cm, respectively, than others at 150 days after planting. In the changes of plant height, PS and DSAB showed taller than others during growth period, cuttings, CBBS, and CBAS grew rapidly in middle growth stage. Excepting main stem and petiole length, other characters were significant for seedling. Fresh weights were different among seedlings. Even though the yield of plants grown from CBAS and CBBS were lower with 34.7 and 36.4 ton/ha, respectively, than 3.6 ton/ha of DSAB; its yield index were over 95%, hence, those of plants grown from cutting and PS were lower with 73 and 87%, respectively. The ratio of tuberous roots over 200g to total tuberous roots per plant was the highest from DSAB. Most of tuberous roots were under 200g per tuberous root from cuttings. CBBS, CBAS, and DSAB are suitable to use seedlings for high yield of yacono. Yacon plant by DSAB much produced tuberous root of over 200g.

• 한국초지조사료학회지
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• 제18권3호
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• pp.217-222
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• 1998

This experiment was carried out to investigate effects of herbicide application method on Calysteria jcqoonica control and corn yield at the forage experimental field, grassland and forage crops division, National Livestock Research Institute, RDA, Suwon from 1996 to 1997. The experiment was arranged in a randomized block design with three replication. The herbicide application consisted of control, 2~3 leaf stage(Dicamba), 5~6 leaf stage(Dicamba) and soil treatment (Pendimethalin). The hybrid of corn used in this experiment was P 3352. The results obtained are summarized as follow; 1. The plant height was the lowest at control and the highest at Dicamba treatment in 5~6 leaf stage, but no significant difference was found among herbicide application method at ear height. Tasseling and silking date were delayed 2~3 day at control. The length and weight of ear were highest at Dicamba treatment in 2~3 leaf stage. 2. The herbicide injury of corn was very slightly after 10-20 day, but corn was recovered soon. The weed control value was 94.2~67.5% at herbicide application plot. 3. The fresh and dry matter yield of Dicamba treatment in 2-3 leaf stage was highest as 42,878 and 16,033kg/ha, respectively. The application of Dicamba increased the DM yield of corn by 13~30%. 4. Herbicide application time had little effect on the ADF, NDF and CP contents, but the forage quality of ear was higher than that of stover. The result of this experiment indicate that the application of Dicamba in 2~6 leaf stage of corn will remove almost all of Calysreria jqonica and increase DM yield of com.

• 한국약용작물학회지
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• 제7권2호
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• pp.89-93
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• 1999

구기자의 비닐 하우스 재배에서 재배방법에 따른 생육, 수량성 및 병해충 발생정도를 알아보기 위하여 충남 청양군 청양농공업고등학교 실습 포장의 비닐 하우스에서 1997년 2월 20일부터 98년 10월5일까지 ‘청양 재래’ 품종을 재식거리, 적심시기 및 적심횟수를 달리하여 재배한 시험 결과를 요약하면 다음과 같다. 1. 재식거리가 멀수록 분지수가 적어졌고, 경장, 경직경, 분지당 엽수, 엽장, 엽폭은 증가하였으며, 개화기 차이는 없었다. 2. 재식거리가 멀수록 분지당 화수, 착과수, 생과중, 전과중은 증가하였으나, 총 수량은 단위면적당 총 주수가 많은 재식거리 $60\;{\times}\;20cm$에서 가장 높았다. 3. 적심시기가 5월5일에서 6월5일로 늦어질수록 생육형질인 경장, 경직성, 분지수, 분지당 엽수, 엽장, 엽폭은 낮았고, 분지당 화수, 착과수, 생과중, 건과중도 모두 낮았다. 4. 적심횟수가 증가할수록 분지수는 많아졌지만, 경장, 경직경, 분지당 엽수, 엽장, 엽폭 모두 감소하였다. 5. 적심횟수가 증가할수록 분지당 개화수, 과립수, 착과율은 감소하였지만, 주당 생과중, 건과중은 증가하였다.