• 한국산림과학회지
• /
• 제97권1호
• /
• pp.127-133
• /
• 2008

본 연구는 장뇌삼(Panax ginseng)의 효율적인 증식과 성공적인 토양 순화의 최적 조건을 구명하기 위해 수행되었다. 장뇌삼의 자엽을 시료로 사용하여 체세포배를 유도한 후, 유도된 체세포배를 발아시켜 얻은 자엽을 다시 시료로 사용하여 2차 체세포배를 유도함으로써 효율성을 증가시켰다. 2차 체세포배의 형성율은 MS 배지의 경우 약 53%이고, WPM 배지의 경우 약 48%인 것으로 나타나 1차 체세포 배의 형성율인 MS 배지와 WPM 배지의 각각 83%, 73%에 비해 약간 떨어지는 것으로 나타났다. 형성된 체세포배는 $GA_3$가 첨가된 WPM 배지에서 발아시키고, 무기염류의 양을 반감시키고, $GA_3$가 첨가된 WPM 배지에서 신장시킨 후, 무기염류를 줄인 SH 배지에서 대기 순화와 무당배양의 처리에 따른 줄기와 뿌리길이, 생존율 차이를 조사하였다. 기내에서 대기 순화와 무당배양 혼용처리 시 가장 정상적인 유식물체로 성장 시킬 수 있었고, 뿌리길이도 가장 길었으며, 생존율 또한 75%로써 가장 높은 생존율을 보였다.

• 열처리공학회지
• /
• 제12권2호
• /
• pp.136-144
• /
• 1999

The study on the wear characteristics of compound layers formed during gaseous nitrocarburising in the medium carbon boron steels and the plain carbon steel has been carried out by using a pin-on-disc type wear test machine under the oil lubricating condition at room temperature and by varying applied loads, sliding speeds and wear distances. Values of friction coefficient measured at the sliding speed of 0.4m/sec under the oil lubricating condition have been shown to decrease considerably with increasing applied load and become gradually a constant value as load is increased to a higher value, showing that the transition load for friction coefficient appears at an applied load of 247.2N. The length and volume wear rates of compound layer have been revealed to relatively constantly increase, also showing that the wear life per unit thickness of compound layer turns out to be superior as porous layer has a denser and thinner appearance. As the sliding speed increases during wear test performed by varying sliding speed at a load of 63.2N under the oil lubricating condition for medium carbon boron steel nitrocarburised in gas atmosphere, the wear rate has been found to increase, the friction coefficient to decrease and the wear life per unit thickness of compound layer to decrease considerably.

• 한국산림과학회지
• /
• 제96권2호
• /
• pp.178-182
• /
• 2007

Rauvolfia serpentina (L.) Benth. ex Kurz is a medicinal plant and an endangered tropical rainforest plant species. Since the field cultivation that aims to fulfill the industrial needs is never accomplished, tissue culture appears to be the most feasible way to improve the quality and quantity of R. serpentina. This experiment used two kinds of explants (roots and shoots) to induce optimal root formation in different combinations of auxin and photoperiod. Each explants exhibited different responses on given treatments. Differentiated root could be produced from explants cultured in IBA 20 mg/L with and without light. The highest number of roots, root length and root weight induced from shoot explants were effective on MS medium containing IBA 20 mg/L and incubated under dark condition, while highest total weight (callus and root) from root explants cultured on MS medium supplemented 10 mg/L IBA and 10 mg/L NAA and incubated under day length (11/13 hr). The root induced from shoot explants produced the highest major alkaloid content. The highest content of ajmaline (2.17 ppm fresh weight) and reserpine (1.30 ppm fresh weight) were observed in shoot explants cultured in MS medium containing combination of IBA 10 mg/L and NAA 10 mg/L and incubated under dark condition, yohimbine (1.47 ppm fresh weight) was in the shoot explants cultured in MS medium containing NAA 20 mg/L and incubated under day length, while serpentine was absent.

• 약학회지
• /
• 제38권5호
• /
• pp.614-620
• /
• 1994

Following the study on the fermentation conditions influencing the production of vitamin $B_{12}$ by Propionibacterium shermanii(Korean J Biotechnol. Bioeng. 7,126-131, 1992), the effects of some factors supplemented in the medium on the production of vitamin $B_{12}$ were studied. Maximum production of vitamin $B_{12}$ was observed when $Co^{+2}$ was supplemented at the concentration of 2-4 ppm in the fermentation medium. Increase of the supplemented $Co^{+2}$ to 12 ppm did not inhibit the growth of the organism, but it accelerated the lysis of the organism. In the literature, peptone was reported to activate the biosynthesis of vitamin $B_{12}$. Examination of the effect of peptone on the growth and the production of vitamin $B_{12}$ showed that at early stage more vitamin$B_{12}$ was observed in the supplemented medium, but no difference was observed in the later stage of fermentation. Examination of the time for addition and the amount of 5,6-dimethylbenzimidazole, a precursor known to influence the production of vitamin $B_{12}$, showed that a maximum yield of vitamin $B_{12}$ was observed when 15 mg/L was added to the fermentation medium after 2 days' incubation. The effect was comparable with the increase of the production of vitamin $B_{12}$ when the fermentation condition was changed to aerobic condition after 2 days' culture under anaerobic condition.

• Journal of Animal Science and Technology
• /
• 제64권6호
• /
• pp.1013-1023
• /
• 2022

Body condition score (BCS) at calving is a vital indicator of the effectiveness of the beginning of lactation in dairy animals. The purpose of this study was to examine the effect of BCS at calving on milk production and transition success in dairy buffaloes. Thirty-six (36) Nili Ravi buffaloes were enrolled at 40 days of expected calving and followed through 90 days of lactation. The buffaloes were categorized into three groups according to their BCS (on a scale of 1-5 with 0.25 increments) as follows: 1) low, buffaloes with BCS ≤ 3.0; 2) medium, buffaloes with BCS 3.25-3.5; and 3) high, buffaloes with BCS ≥ 3.75. All buffaloes were fed a similar diet ad libitum. The lactation diet had increased concentrate allowance according to milk yield. The results revealed that the BCS at calving did not affect milk yield; however, fat percentage (fat%) was lower in the low-BCS group. Dry matter intake (DMI) was similar among the treatment groups, although post-calving BCS loss was greater in the high-BCS group compared to the medium- and the low-BCS groups. Similarly, the buffaloes in the high-BCS group had higher non-esterified fatty acids (NEFA) concentration compared to the low- and medium-BCS groups. No cases of metabolic disorders were observed during the study. The present results suggest that the buffaloes in the medium-BCS group appeared to perform better compared to the low- and the high-BCS groups with respect to milk fat% and blood NEFA concentration.

• 한국자원식물학회지
• /
• 제7권2호
• /
• pp.171-175
• /
• 1994

The effects of medium, hormones, and PFP on the proliferation of red callus in leaf tissue cultures of Garden orach(Atriplex hortensis L.) was investigated. As a result,88% of leaf tissues formed eallus on MS nledium containing 2mg/$\ell$ 2,4-D. Fresh weight of callus was higher on MS medium than on Bsand NN media. It was also found that 2, 4-D was more effective than Dicamba and Picloram. The op-timum concentrations of hormones for callus proliferation depended on culture media. Isolated red cal-lus grew markedly both on MS medium supplemented with 1-2mg/$\ell$ 2, 4-D and Bs medium contain-ing 2-4111g/$\ell$ 2,4D. Callus proliferated on B5 and NN media containing Dicabma Img/$\ell$ as well as onthe same media containing 2mg/$\ell$ Picioram. The addition of PFP concentrations of 2, 5, and 40mg/ $\ell$rcspectiely to culture medium caused increase of callus fresh weight, especially under light condition.

• 아시안잔디학회지
• /
• 제12권4호
• /
• pp.195-202
• /
• 1998

The development of a protocol for high efficiency of embryogenic callus separation, maintenance and plant regeneration from the seeds of zoysiagrass cv. Zenith was studied. Embryogenic callus ratio is absolutely determined by genotype, but by adding high concentration of copper into medium, changing light condition and maintaining callus on initial induction medium for 8∼10 weeks, embryogenic callus can be easily distinguished and its growth can be promoted. There were significant differences among selected callus lines (each from one seed) according to their growth rates and regeneration percentages. Callus pre-treatment with activated charcoal inhibited callus growth, increased the level of precocious germination during culture and promoted shoot cluster formation after transfer to regeneration medium. For long-term callus maintenance, N6AA medium was better than MS medium, because the former inhibited non-embryogenic callus formation and kept vigor of embryogenic callus. The best callus lines Z-(5) has been successfully used for transformation and somaclonal variation selection in our laboratory.

• 산업경영시스템학회지
• /
• 제25권4호
• /
• pp.32-39
• /
• 2002

This study investigated the management environment of medium and small business by examining the role of medium and small business in national economics, the change in management condition, and the problems in quality and technique. Also we analyzed problems in the past quality control activity of our medium and small business, and examined the driving direction and introduction method of QM. And to understand the effect of manager's concern in quality management to observe the quality system before and after introduction of QM. A target for this investigation is the medium and small business which has introduced QM through ISO 9000.

• 한국작물학회지
• /
• 제45권1호
• /
• pp.32-37
• /
• 2000

The in vitro culture of rice panicles is a culturing technique only panicle without other organs in culture solution containing organic substance, so that would be useful to study how assimilate supply affects grain development and maturation. To find the optimum stage for in vitro culture, rice panicles grown in greenhouse were sampled periodically after anthesis and cultured in nutrient medium. The panicles older than 1 weeks after anthesis had produced normal grains. Grain-filling was apparently dependent upon sucrose concentration (8-12 %) in medium, but not affected by nitrogen concentration supplied with glutamine. As far as rice panicle was supplied with sucrose and N in nutrient medium, grains continued accumulation of dry matter and maturation regardless to light condition. Considerably, grain-filling was improved when panicles were positioned horizontally inside flask, so that each grain was partially submerged to nutrient medium.

• Computers and Concrete
• /
• 제22권2호
• /
• pp.221-225
• /
• 2018

In this paper, vibration analysis of concrete foundations resting on soil medium is studied. The soil medium is simulated by Winkler model considering spring element. The concrete foundation is modeled by thick plate elements based on classical plate theory (CPT). Utilizing energy method consists of potential energy, kinetic energy and external works in conjunction with Hamilton's principle, the motion equations are derived. Assuming the simply supported boundary condition for the concrete foundation, the Navier method is used for calculating the frequency of the structure. The effect of different parameters such as soil medium, mode numbers, length to width ratio and length to thickness ratio of the concrete foundation are shown on the frequency of the structure. At the first, the results are validated with other published works in order to show the accuracy of the obtained results. The results show that considering the soil medium, the frequency of the structure increases significantly.