Background: The functioning of the serratus anterior (SA) muscle is essential to normal scapulohumeral rhythm during forward flexion (FF) of the shoulder. Also, SA weakness and overuse of the upper trapezius (UT) is observed in patients with shoulder dysfunction and trapezius myalgia. We designed a combination exercise involving FF and scapular protraction with resistance (CFFSP) to activate the SA muscle and to deactivate the UT muscle. Objects: The purpose of this study was to determine whether or not CFFSP would be more effective in activating the SA muscle than FF alone and FF with scapular protraction (FFP). Methods: Nineteen subjects (12 men and 7 women) participated in this study and performed FF, FFP, and CFFSP at 120°. Surface electromyography was applied to the SA, UT, and pectoralis major (PM) muscles, as was one-way analysis of variance (ANOVA) with repeated measures. Statistical significance was set at .05. Bonferroni adjustment was used to counteract the problem of multiple comparisons, with a statistical level of significance of .017 (.05/3). Results: A statistically significant difference was found in relation to the three positions for the SA muscle (p<.001) and the SA/UT ratio (p=.005) using ANOVA. Significantly different results, depending on the position, were also demonstrated using the Bonferroni post-hoc test for the SA muscle (FF=28.27±16.20, FFP=45.66±15.81, and CFFSP=62.4±27.21) and for the SA/UT ratio (FF=3.04±2.14, FFP=3.61±2.38, and CFFSP=5.95±3.01). Significant differences between the three positions was not found regarding the average amplitude of SA/PM muscle ratio (SA/PM: p=.060). Conclusion: We recommend the use of CFFSP to strengthen the SA muscle at 120°.

습식제련 공정은 대부분 황화광석을 원료로 하기 때문에 제련 과정 중 황산 농도 2～15 wt%의 불순물을 함유한 폐 황산이 발생하게 된다. 발생하는 폐 황 산에는 다양한 희소금속들이 포함되어 있으나, 현재 공정수에서 희소금속 처리 기술부족으로 중화되어 폐기되고 있다. 이 과정에서 막분리 공정을 적용할 경우 희소금속을 친환경적이면서 효율적으로 회수할 수 있다. 본 연구에서는 폴리아 미드 계면중합을 위하여 다공성 지지막 위에 방향족 아민모노머와 트리메조일 클로라이드를 사용하여 산에 안정한 폴리아미드 나노여과막을 제조하였고, 제조 된 막의 투과분리 성능에 대하여 살펴보았다. 그리고 제조된 분리막이 내산성을 가지는지 평가하기 위하여 15 wt%의 황산용액에 침지하여 일별 투과수량 및 이온제거율을 측정하였다.

본 연구에서는 제련 공정에서 발생하는 희소금속을 함유한 폐산용액을 효율 적/경제적으로 회수하기 위해 부식 억제 특성을 가진 지방족 아민(Aliphatic Amine)를 첨가제로 사용하여 내산성이 향상된 복합 NF 분리막을 제조하고자 한다. 지방족 아민를 첨가한 내산성 NF 분리막은 다공성 지지막 위에 polyamide 계면중합법을 이용하여 제조하였고 제조한 내산성 NF 분리막은 15 wt% 황산에 노출한 후, 75psi 압력의 cross-flow 방식으로 내산성 투과실험을 진행한 결과를 flux와 rejection을 통해 확인하였다. 또한 XPS, FE-SEM, ATR-FTIR 등을 통해 제조된 막의 특성을 분석하였다.

In this study, SCM440 alloys are investigated to research the effect of wear resistance. For this purpose, three wear factors which are friction force, wear loss and coefficient of friction applied to test wear-resistance. For the wear test, ball-on-disk was used to assess the variation of wear characteristics. Lastly, the coefficient of wear was calculated by using the Archard's wear equation in SCM440 alloys. The applied normal load was fixed at 30N in all test. The test results showed that SCM440 alloy's Vickers hardness average value is near 671.4Hv, the friction force is 4.11N through the Ball-on-disk test, the coefficient of friction and the wear loss are 0.431 and 0.080 respectively. Finally, Archard’s wear value of SCM440 alloys could be shown approximately 0.1514.

Worldwide, increasing numbers insecticide resistant insect is one of the main problem in this agricultural era. To manage the insecticide resistance, IRAC suggest some tips for farmers : 1. Sequence or alteration of insecticide based on MOA 2. Choosing the effective insecticide. In this point raised following question : How to distinguish the effective or non-effective insecticide. Until now, bioassay is the right answer. However that is a very time-consuming, labor-intensive, and costly process, so we were hoping that molecular based diagnosis could be alternate. It can summarized following steps : 1. Identification of insecticide resistance mechanism 2. Marker development 3. Molecular diagnosis 4. Selection of non-effective insecticide. Here we focused on the development of insecticide resistance marker. Point mutation in target site of insecticide is a good example. Up or down-regulation of specific gene and/or existence of chimeric gene is another example from Helicoverpa armigera.

Control of the vector mosquitoes is critical for implementation of patient’s decrease. Vector mosquito control has been mainly carried out using pesticides in Republic of Korea (ROK), which has developed the resistance against selected insecticides. Voltage-gated sodium channel (VGSC) and Acethylcholine esterase (AchE) are the target of several classes of insecticides. Genetic mutations of VGSC and AchE have been documented to confer resistances to pyrethroids and organophosphates in mosquitoes, respectively. In our studies, the insecticidal resistable level of An. sinensis from four malaria risk areas near Demilitarized Zone (DMZ) was measured. The partial sequence of An. sinensis voltage gated sodium channel (VGSC) IIS6 domain for Kdr gene and ace1 gene for AchE was sequenced. An. sinensis from two areas demonstrated significantly higher resistance to pyrethroids and mutation rates of Kdr gene were comparatively higher. In all tested areas An. sinensis showed high insecticidal resistance to organophosphates and > 70% of mutation rates of ace1 gene ware higher. Understanding the mechanisms of insecticide resistance among vector mosquitoes populations is very important to efficient and effective vector control.

Among several insect pests in the potato fields, Liriomyza huidobrensis, pea leafminer, is emerging as a new threat to potato plants. Adult females damage the host mesophyll cells host due to ovipositor probing. After egg hatching, the eclosing larva also damage the leaf by mining the mesophyll and causing tissue death. Despite the importance of leafminer in potato production, there is no information available regarding its resistance level to potato cultivars in Korea. Using choice test, 21 potato cultivars consisting of 11 early-maturing, 6 mid-maturing and 4 late-maturing cultivars were evaluated the resistance to pea leafminer in the greenhouse and field condition. In this test, significant differences for resistance were observed. High levels of resistance to leafminers were obtained from cvs. Namsuh, Seohong, Jayoung and Superior. These resistant cultivars might be useful in future breeding programmes.

Bacillus thuringiensis (Bt) produces a variety of insecticidal crystal proteins and widely used as one of the most successful biological control agents. Recently, studies that introduce cry genes into crops to create pest resistance have made much progress, and the total area of land planted with Bt crops has increased substantially. In this study, pest resistance of 8 transgenic Bt rice events with a synthetic cry1Ac gene linked to rice rbcS-tp sequence were assessed under laboratory conditions. Bioassays were performed against Cnaphalocrocis medinalis, which is a significant pest of rice in Asia. C. medinalis larvae were shown to be susceptible to all eight events, even though there were differences between the causes of death. The results differed between developmental stages of the larvae, despite the fact that all 8 events led to high mortalities. These results may be a significant foundation for the evaluation of improved transgenic Bt rice.

Vollenhovia emeryi (Formicidae: Myrmicinae) is divided into two morphs based on the wing length of the queen caste: the long-winged with a normal wing and the short-winged with the aberrant short wing. The phylogenetic analysis shows that the short-winged is derived from the long-winged. In Korea, only the long-winged morph is infected with Wolbachia while the short-winged is devoid of the bacterium suggesting that the short-winged evolved the resistance to the bacterial infection. Intriguingly, some Japanese short-winged colonies proved to still be infected with the bacterium. We hypothesized that the infected Japanese short-winged is the intermediate form in the process to complete cure. However, the data of the MLST and the measurement of Wolbachia density did not support our hypothesis. Our further experiment using microsatellite markers shows that the infected Japanese short-winged shows the similar genetic background to the long-winged. In this presentation we will discuss the potential resistance evolution in the Korean short-winged and future research direction at the genome level.

본 연구에서는 플라스틱 온실에서 사용하는 죔쇠의 성능 평가 시 시험편 끝단의 구속조건이 미끄럼 저항력에 미치는 영향을 분석하기 위해 시험편 구속조건을 실험변수로 판형죔쇠의 미끄럼 저항력을 측정하였다. 각 구속조건별로 측정한 미끄럼 저항력의 평균값은 서까래 고정-고정단이 가장 컸으며, 내재해형 죔쇠의 평가 기준 값과 비교한 결과에서도 서까래 고정-고정단의 경우에만 기준을 만족하는 것으로 나타났다. 그러나 서까래 고정-고정단 구속조건은 다른 구속조건들에 비해 산 포도가 상대적으로 크게 나타나 신뢰성이 떨어지는 결과를 보였다. 또한, 일원분산 분석결과에서도 서까래 고정- 고정단은 다른 구속조건들과 비교해 미끄럼 저항력이 유의한 차이를 보였다. 따라서 시험편 구속조건이 미끄럼 저항력 평가에 영향을 미친다고 판단하며 연구자 및 기술자들이 죔쇠의 미끄럼 저항력을 측정할 때에는 시험편의 구속조건이 결과값의 신뢰성에 미치는 영향을 면밀히 검토해야 할 것으로 판단된다.

소음공해를 방지하기 위한 방음시설물로서 도로, 철로 및 공항 주변에 설치되는 방음벽은 주로 외부에 설치되어 풍하중에 노출된다. 지속적이고 반복적인 풍하중은 방음벽의 피로를 야기하며 높은 풍속이 발생할 경우 붕괴되는 경우도 흔히 발생하고 있다. 본 논문에서는 반사형, 통풍형 등 방음벽의 유형별로 방음벽에 작용하는 풍하중의 발생 과정과 내풍성능 개선방안에 대해서 전산해석을 수행하였다. 통풍형 방음벽의 경우 수압면적이 감소한 것에 비하여 풍하중은 다소 낮은 6.76%의 감소율이 나타난 원인은 풍하면의 통풍공 주변에 발달한 국부적 부압으로 판단되었다. 추가적인 풍하중 저감을 위하여 박리에 의한 와류의 규모를 개선하기 위한 방안으로 상부에 슬릿을 설치한 결과, 최대 14.67%의 감소효과를 나타내었다. 또한 슬릿의 간격이 250mm일 때 15.41%로 풍하중이 감소율이 상대적으로 우수하였으며, 이는 방음벽 상단과 슬릿에 의한 기류의 상호작용이 와류의 규모와 발달에 영향을 미친 것으로 판단된다.

본 연구에서는 KVLCC2의 파랑 중 부가저항과 운동을 Unsteady Reynolds-Averaged Navier-Stokes(URANS) 방법과 3차원 포텐셜법을 이용하여 추정하였다. 수치해석은 3가지 선박속도(설계, 운항, 정지 속도)에서 다양한 파랑조건에서의 선박의 부가저항 및 수직운동(상하 및 종 동요 응답)의 추정에 대해 수행되었다. 첫째, CFD와 3차원 포텐셜 방법을 이용하여 규칙파에서의 선박속도와 파랑조건에 따른 선박의 부가저항과 운동을 추정하고 실험값과의 비교를 통해 두 수치 해석법의 특징을 살펴보았다. 둘째, CFD를 이용한 선박의 속도별 비정상 파형 분포와 선박의 부가저항 및 운동의 시간이력에 대해 해석하였다. 수치 격자계에 대한 수렴도를 확인하였고 수치계산과 모형시험 결과를 비교하여 사용한 수치 기법들을 체계적으로 검증 하였다. 이를 통해 본 연구에 적용된 수치해석법들의 신뢰성과 선속변화에 따른 파랑 중 부가저항과 선박의 수직운동에 대한 관계를 확인하였다.

During the field operation of the Korean MBT(Main Battle Tank), the multi-smoke projectile launching system failed to function. As a result of conducting analysis, it was confirm that the gear shaft of reducer was failed. Therefore, a study on improvement in impact resistance of the reducer was conducted. The reducer was improved impact resistance by changing the design and material of gear shaft. The reliability of modified reducer was investigated by finite element analysis, performance and environmental tests. As a result of analysis, a strength of the modified gear shaft was improved by about 20 times than before improvement. The results of performance and environmental test show that the modified reducer is applicable for Korean MBT under the severe conditions. The quality improvement of multi-smoke projectile launching system contributes to survivability of Korean MBT.