• Journal of Ecology and Environment
• /
• 제35권3호
• /
• pp.235-242
• /
• 2012

Mikania micrantha, a neo-tropical vine, is spreading rapidly in the tropical part of Nepal and is now threatening the rural ecosystem including biodiversity and rural livelihoods. However, no attempt has been made to control the spread of M. micrantha. As a result, the vines are spreading freely and rapidly. After a thorough literature review and assessment of forest management practices, we proposed a manual cutting method, as it suits the Nepalese situation for several reasons: required labor is readily available, as local communities are managing forest patches, and the method does not have any potential adverse effects on non-target native species. Experimental plots were laid out in August 2011 to examine the effectiveness of manual cutting. Two different site types based on canopy coverage were selected and divided into three blocks based on cutting strategy. Four treatments were assigned across the experimental plots following a complete block design. We harvested above-ground biomass according to the assigned treatment. The results suggested that there should be at least two consecutive cuttings within a 3-week interval before flowering, and that three consecutive cuttings resulted in 91% mortality of the vines. In addition, cutting promoted regeneration of native plant species. Employing regular cutting operations can modify understory shade enhancing regeneration of native species, which is a desirable condition to constrain proliferation of M. micrantha. Periodic cuttings reduced the competitiveness of M. micrantha regardless of canopy openness, but native ground cover should be retained.

• Journal of Ecology and Environment
• /
• 제41권3호
• /
• pp.66-71
• /
• 2017

Background: The sprouts of oak species play an important role in maintaining the oak community in a disturbed environment. In this study, we cut 1-year-old oak in three times during the 3 years and measured the sprout responses to know sprouting ability of six deciduous oaks in Korea. Results: Oak sprouts have appeared in spring and fall, and some of the sprouts had lifespan as short as a month. As the number of cutting increases, sprout number of Quercus acutissima increased whereas the other oak species decreased or died. The average number of sprouts over the 3 years was from 1.4 (Quercus mongolica) to 2.2 (Q. acutissima) per individual. Quercus serrata died after the second cutting, and Quercus dentata died after the third cutting. So, the two species have the lowest sprouting ability among six oak species. The sprouts grew actively during fall and slowly in summer. The sprout length during the 3 years was in the following descending order: Q. acutissima, Quercus aliena, Q. dentata, and Q. mongolica. Sprout of Q. acutissima and Q. aliena generated steadily over the 3 years, and sprout of Quercus variabilis and Q. mongolica was changed by year. After the 3 years, the number of sprouts increased only in Q. acutissima but sprout number of the other five oak species decreased. The sprout length of Q. acutissima, Q. aliena, and Q. variabilis increased, but sprout length of the other three oak species decreased. The average survival rate of saplings over the 3 years was in the following descending order: Q. acutissima, Q. aliena, Q. variabilis, and Q. mongolica. Conclusions: As a result, the sprouting ability of Q. acutissima was the highest. Such level of sprouting ability may be the evidence of how Q. acutissima community exists as a dominant species in a disturbed environment in lowlands of Korea peninsula.

• 화훼연구
• /
• 제17권4호
• /
• pp.256-261
• /
• 2009

본 연구는 하국용으로 가장 많이 재배되고 있는 '백선' 품종의 플러그 묘 생산에 있어서 삽수의 조건이 묘의 지상부 생육과 발근 및 절화생육에 미치는 영향을 알아보고자 실시하였다. 삽수에 부착된 엽수가 많을수록 묘의 지상부 생육과 발근이 양호하였다. 삽수 길이에 따른 지상부 생육에는 큰 차이가 없었으나, 발근은 삽수 길이가 5cm 이상인 처리에서 양호하였다. 삽수의 굵기가 굵을수록 지상부의 생체중이 무거웠으며, 굵기가 5.5 mm 처리에서 형성된 뿌리수가 가장 많았다. 삽수에 부착된 엽수가 많을수록 절화장이 길었고, 절화무게도 무거웠다. 삽수의 길이가 7~11 cm 처리에서 절화장, 절화무게, 엽수, 설상화수 등 절화의 생육이 양호하였다. 삽수 굵기가 5.5 cm 처리에서 다른 처리에 비해 절화 생육이 우수하였다. 띠라서 '백선' 플러그 묘 생산시 굵기가 5.5 mm 정도의 7cm 길이의 삽수에 잎을 4장 부착하여 삽목하는 것이 묘의 생육 및 발근에 효과적이고, 정식 후 절화의 생육에도 적합하였다.

• 한국정밀공학회지
• /
• 제15권6호
• /
• pp.58-63
• /
• 1998

There are lots of factors that are related to the geometric characteristics of machined surface. Among them, the tool path and milling mode (up cut milling or down cut milling) are the easiest controllable machining conditions. Thus, the first objective of this research is to study the effects of them on the milled surface that is generated by an end milling tool. To get precision parts, not only the machining process but also the measurement of geometric tolerance is important. But, this measurement requires a lot of time, because the infinite surface points must be measured in the ideal case. So, the second objective is to propose a simple flatness measurement method that can be available instead of the 3-D geometric tolerance measurement method, using a scale factor and characterized points. Finally, it is also shown that the possibility of flatness improvement by shifting the consecutive fine cutting tool path as compared with the last rough cutting tool path.

• 한국정밀공학회지
• /
• 제12권2호
• /
• pp.23-34
• /
• 1995

This paper is concerned with effective and reliable tool breakage detection method using pattern characteristics of feed motor current in milling operations. Correlation coefficient is derived from the feature vector of signal for two consecutive which are extracted feed motor current over three spindle revolutions. The changing pattern of correlation coefficient is continuously compared to detect tool breakage and monitor cutting conditions. This proposed monitoring scheme is not affected by different tools, friction of motion, and varying cutting conditions and material shapes. Experimental results are presented to support the proposed monitoring scheme.

• 생물환경조절학회지
• /
• 제21권4호
• /
• pp.385-391
• /
• 2012

국내에서 육성된 딸기 품종인 '매향' 및 '설향'을 대상으로 비가림 포트 육묘 시 런너의 절단 시기에 따른 자묘의 생육과 정식 후 수량을 2작기(2009년 및 2010년)에 걸쳐 검토하였다. 자묘는 정식일(2009년 9월 11일 및 2010년 9월 10일)을 기준으로 30일, 20일, 10일 및 5일 전에 모주로부터 런너를 절단하였다. 런너의 절단 시기가 늦을수록 모주에서 양수분이 육묘 후기까지 자묘로 공급되어 지상부 생체중, 관부직경 및 엽록소 함량은 증가하는 경향을 보였다. 반면에 근중 등 지하부 생육은 런너의 절단 시기가 빨라서 모주로부터 자묘의 독립 기간이 길수록 증가하였다. 모주에서 런너를 절단한 경우의 관수 요구량이 런너를 절단하지 않은 처리구에 비하여 29.7% 증가하였다. 또한, 런너를 절단하였을 경우에 런너를 통하여 탄저병이 침입한 경우가 런너를 절단하지 않은 처리구에 비하여 37.6% 높게 나타났다. 정식 후 정화방의 출뢰 및 개화 개시기는 런너 절단 시기가 늦을 경우 2~3일까지 지연되었으나 런너 절단 시기에 따른 조기 수량의 차이가 없으므로 런너 절단 시기를 정식일의 5~10일 전인 8월 하순 이후로 늦추어 실시하는 것이 탄저병 발생 경감 측면에서는 유리한 것으로 생각된다.

• 한국생활과학회지
• /
• 제17권1호
• /
• pp.115-126
• /
• 2008

The construction of an athlete's tight-fitting garments is very important to the wearer in terms of athletic performance. Therefore pattern development of tight-fitting garments must allow for the full range of human movement and postures. In this study the relationship between the construction of a skate pants pattern and clothing fitting was explored with the aim of improving the comfort of the clothing. The four male subjects were university students between the ages of 20 to 24. Subjective wear sensations of the experimental garments were rated using a seven-point Likert scale on four consecutive days. While wearing the garments, subjects were asked to take five different postures including waist flexion, sitting and others. A Likert-type scale was used for the evaluation, with 7 points indicating the best fit in tight-fitting pants. Results showed differences in the front-rise length and back-rise length between basic pants(A) and modified pants(B,C,D) were -5.16cm and +5.64cm. Comparing the basic pants pattern(A) with modified pants pattern(B), the latter was superior to basic pants(A) in terms of pressure sensation and closeness of fit, but there was no significant difference. Among the four tight-fitting skate pants, A and B pants were superior to the others in terms of fitting and stability of waist and hip sections. In the case of the skate pants, the number of cutting lines in the pattern had an influence on clothing comfort. A minimum cutting line for tight skate pants was better than a maximum cutting line in terms of clothing comfort.

• KIEE International Transactions on Electrophysics and Applications
• /
• 제4C권2호
• /
• pp.55-59
• /
• 2004

Throughout manufacturing processes, pulse shaping is required for material processing and it is regarded as an important (actor according to the specific characteristics of materials. Therefore, this study suggests a highly appropriate pulse shaping technique using a multi-switching method. This is a pulse superposition method in which one flash lamp can consecutively turn on by the double switching of the discharging system. It is possible to construct a variety of pulse shapes and pulse widths by the consecutive trigger of the silicon-controlled rectifiers (SCR) of a PIC (program integrated circuit) one-chip microprocessor. The use of this technique can provide a number of advantages to people who require suitable pulse shaping for particular applications such as welding, cutting, and drilling.

• 한국축산식품학회지
• /
• 제28권5호
• /
• pp.562-566
• /
• 2008

본 연구에서는 포장돈육 가공공정에서 교차오염의 정도를 알아보기 위하여 실제 돈육 가공공정에서 돈육과 빈번하게 접촉하는 작업자의 손(polyethylene glove 착용, 면장갑 착용, 맨손) 및 작업도구(칼, 도마)를 대상으로 각각에 대하여 Salmonella spp.의 상호 교차오염 전이율을 분석하였다. 오염된 돈육에서 작업자로의 전이율은 면장갑이 38.80%로 가장 높았고, 다음이 PG 3.11%,맨손 1.35% 순으로 나타났다. 특히, 면장갑의 경우 면 장갑으로 전이된 균이 다시 맨손으로의 재오염 전이(0.07%)가 이루어지는 것으로 나타났으며, 오염된 돈육에서 칼과 도마로의 전이율은 0.20-1.99%이다. 반대로 오염된 작업자로부터 돈육 및 기구로의 전이율은 0.0015-0.21%로 전체적으로 오염된 돈육으로부터의 작업자의 손과 기구로의 전이보다 상당히 낮은 수준으로 전이되었다. 따라서 PG 착용이 작업공정에서의 교차오염을 줄이거나 예방하는 효과를 얻을 수 있는 것으로 파악되었다. 축산물 작업공정에서의 교차오염은 원료육에서 손 또는 장갑, 도마, 칼 등으로 오염이 전이되고 이들이 다시 돈육을 오염시킬 수 있으므로, 안전한 식품생산을 위해서는 이러한 교차오염의 연속성을 차단하는 것이 무엇보다 중요함을 확인하였다.

• 한국산림과학회지
• /
• 제97권5호
• /
• pp.540-546
• /
• 2008

Enrichment planting has been used as one of the promising restoration techniques to accelerate the natural restoration process of secondary forests or logged-over forests in Myanmar, The objectives of this study were to examine the growth performances of two commercial species such as Teak (Tectona grandis Linn f.) and Padauk (Pterocarpus macrocarpus Kurz) in response to different canopy opening treatments and to examine the suitability of these species in enrichment planting activities for the restoration of degraded tropical forests in Myanmar. In this study, split plot design was applied, and three levels of canopy openings were experimented. The survival rate and height growth of two species were measured four times with 6 month interval. The root collar diameter (RCD) was also measured in the last assessment. Although the survival rate of seedlings was not significantly different among the three treatments (p>0.05) as well as between two species (p>0.05) for all consecutive measurements, height (p<0.05) and RCD were significantly different (p<0.001) among the treatments, T. grandis seedlings thrived best under complete canopy opening (i.e., 5 m width canopy opening with strip-clear cutting) while P. macrocarpus seedlings under partial canopy opening (without felling of marketable tree species). Because this study is concerned with only for young stage of seedlings, continuous assessment and follow-up tending activities are needed to verify the species suitability and optimum width of canopy opening for enrichment planting activities in restoration of degraded forests of Myanmar.