• 농업생명과학연구
• /
• 제46권5호
• /
• pp.1-10
• /
• 2012

본 연구는 설악산, 발왕산, 태백산, 오대산의 아고산대에 분포하는 주목 군락의 보존과 효율적인 관리방안을 제시하기 위하여 종조성과 흉고직경급을 조사, 분석하였다. 각 조사지의 교목 아교목 관목층의 층위별 식생은 설악산 11, 22, 33종, 발왕산 15, 21, 33종, 태백산 10, 23, 36종, 오대산 14, 30, 32종으로 구성되어 있다. 층위별 중요치 분석 결과, 전 조사지의 교목층은 주목과 분비나무, 아교목층은 주목, 분비나무, 시닥나무, 관목층에서는 미역줄나무의 중요치가 가장 높은 것으로 분석되었다. 전 조사지에 있어서 종다양도는 교목층 0.834~1.234, 아교목층 1.125~1.329의 범위 내에 있는 것으로 분석되었다. 흉고직경 분포에서는 오대산지역의 주목개체군이 역J자형의 유형을 보이고 있어 주목군락이 유지될 수 있을 것으로 판단된다.

• 농업생명과학연구
• /
• 제46권6호
• /
• pp.33-41
• /
• 2012

본 연구는 덕유산, 계방산의 가문비나무 군락의 보존을 위한 기초자료를 제시하기 위하여 종조성과 흉고직경급을 조사, 분석하였다. 두 조사지의 교목 아교목 관목층의 층위별 식생은 덕유산이 8, 20, 26종, 계방산이 12, 23, 33종으로 구성되어 있다. 층위별 중요치 분석 결과, 덕유산 교목층은 가문비나무, 사스래나무, 구상나무, 아교목층은 사스래나무, 신갈나무, 관목층은 조릿대가 중요치가 높았으며, 계방산의 교목층은 가문비나무, 사스래나무, 분비나무, 아교목층은 시닥나무, 부게꽃나무, 관목층은 미역줄나무의 중요치가 가장 높은 것으로 분석되었다. 조사구의 층위별 종다양도의 경우 교목층은 덕유산 0.779, 계방산 0.984, 아교목층은 덕유산 1.052, 게방산 1.161, 관목층은 덕유산 0.823, 계방산 1.304로 분석되었다. 흉고직경 분포에서는 덕유산지역의 가문비나무 개체군이 역J형의 유형이 나타나고 있어 당분간 가문비나무군락이 유지될 수 있을 것으로 판단된다.

• Journal of Microbiology and Biotechnology
• /
• 제29권10호
• /
• pp.1495-1505
• /
• 2019

The Burkholderia cepacia complex (BCC) is capable of remaining viable in low-nutrient environments and harsh conditions, posing a contamination risk in non-sterile pharmaceutical products as well as a challenge for detection. To develop optimal recovery methods to detect BCC, three oligotrophic media were evaluated and compared with nutrient media for the recovery of BCC from autoclaved distilled water or antiseptic solutions. Serial dilutions ($10^{-1}$ to $10^{-12}CFU/ml$) of 20 BCC strains were inoculated into autoclaved distilled water and stored at $6^{\circ}C$, $23^{\circ}C$ and $42^{\circ}C$ for 42 days. Six suspensions of Burkholderia cenocepacia were used to inoculate aqueous solutions containing $5{\mu}g/ml$ and $50{\mu}g/ml$ chlorhexidine gluconate (CHX) and $10{\mu}g/ml$ benzalkonium chloride (BZK), and stored at $23^{\circ}C$ for a further 199 days. Nutrient media such as Tryptic Soy Agar (TSA) or Tryptic Soy Broth (TSB), oligotrophic media (1/10 strength TSA or TSB, Reasoner's $2^{nd}$ Agar [R2A] or Reasoner's $2^{nd}$ Broth [R2AB], and 1/3 strength R2A or R2AB) were compared by inoculating these media with BCC from autoclaved distilled water and from antiseptic samples. The recovery of BCC in water or antiseptics was higher in culture broth than on solid media. Oligotrophic medium showed a higher recovery efficiency than TSA or TSB for the detection of 20 BCC samples. Results from multiple comparisons allowed us to directly identify significant differences between TSA or TSB and oligotrophic media. An oligotrophic medium pre-enrichment resuscitation step is offered for the United States Pharmacopeia (USP) proposed compendial test method for BCC detection.

• Safety and Health at Work
• /
• 제7권2호
• /
• pp.111-119
• /
• 2016

Background: Shift work and/or sleep quality may affect health. We investigated whether shift work and sleep quality, separately and jointly, were associated with abnormal levels of triglycerides, total cholesterol (TC), and low-and high-density lipoprotein cholesterol in 360 police officers (27.5% women). Methods: Triglycerides, TC, and high-density lipoprotein were analyzed on the Abbott Architect; low-density lipoprotein was calculated. Shift work was assessed using City of Buffalo payroll work history records. Sleep quality (good, ${\leq}5$; intermediate, 6-8; poor, ${\geq}9$) was assessed using the Pittsburgh Sleep Quality Index questionnaire. A shift work + sleep quality variable was created: day plus good sleep; day plus poor sleep; afternoon/night plus good; and poor sleep quality. Mean values of lipid biomarkers were compared across categories of the exposures using analysis of variance/analysis of covariance. Results: Shift work was not significantly associated with lipids. However, as sleep quality worsened, mean levels of triglycerides and TC gradually increased but only among female officers (age- and race-adjusted p = 0.013 and 0.030, respectively). Age significantly modified the association between sleep quality and TC. Among officers ${\geq}40$ years old, those reporting poor sleep quality had a significantly higher mean level of TC ($202.9{\pm}3.7mg/dL$) compared with those reporting good sleep quality ($190.6{\pm}4.0mg/dL$) (gender- and race-adjusted p = 0.010). Female officers who worked the day shift and also reported good sleep quality had the lowest mean level of TC compared with women in the other three categories (p = 0.014). Conclusion: Sleep quality and its combined influence with shift work may play a role in the alteration of some lipid measures.

• Wind and Structures
• /
• 제28권2호
• /
• pp.71-87
• /
• 2019

The yaw and interference effects of blades affect aerodynamic performance of large wind turbine system significantly, thus influencing wind-induced response and stability performance of the tower-blade system. In this study, the 5MW wind turbine which was developed by Nanjing University of Aeronautics and Astronautics (NUAA) was chosen as the research object. Large eddy simulation on flow field and aerodynamics of its wind turbine system with different yaw angles($0^{\circ}$, $5^{\circ}$, $10^{\circ}$, $20^{\circ}$, $30^{\circ}$ and $45^{\circ}$) under the most unfavorable blade position was carried out. Results were compared with codes and measurement results at home and abroad, which verified validity of large eddy simulation. On this basis, effects of yaw angle on average wind pressure, fluctuating wind pressure, lift coefficient, resistance coefficient,streaming and wake characteristics on different interference zone of tower of wind turbine were analyzed. Next, the blade-cabin-tower-foundation integrated coupling model of the large wind turbine was constructed based on finite element method. Dynamic characteristics, wind-induced response and stability performance of the wind turbine structural system under different yaw angle were analyzed systematically. Research results demonstrate that with the increase of yaw angle, the maximum negative pressure and extreme negative pressure of the significant interference zone of the tower present a V-shaped variation trend, whereas the layer resistance coefficient increases gradually. By contrast, the maximum negative pressure, extreme negative pressure and layer resistance coefficient of the non-interference zone remain basically same. Effects of streaming and wake weaken gradually. When the yaw angle increases to $45^{\circ}$, aerodynamic force of the tower is close with that when there's no blade yaw and interference. As the height of significant interference zone increases, layer resistance coefficient decreases firstly and then increases under different yaw angles. Maximum means and mean square error (MSE) of radial displacement under different yaw angles all occur at circumferential $0^{\circ}$ and $180^{\circ}$ of the tower. The maximum bending moment at tower bottom is at circumferential $20^{\circ}$. When the yaw angle is $0^{\circ}$, the maximum downwind displacement responses of different blades are higher than 2.7 m. With the increase of yaw angle, MSEs of radial displacement at tower top, downwind displacement of blades, internal force at blade roots all decrease gradually, while the critical wind speed decreases firstly and then increases and finally decreases. The comprehensive analysis shows that the worst aerodynamic performance and wind-induced response of the wind turbine system are achieved when the yaw angle is $0^{\circ}$, whereas the worst stability performance and ultimate bearing capacity are achieved when the yaw angle is $45^{\circ}$.

• 대한통합의학회지
• /
• 제8권4호
• /
• pp.223-230
• /
• 2020

Purpose : The purpose of this study was to examine the effects of tools (i., extracorporeal shock wave therapy, massage gun, and foam roller) on range of motion, muscle tone and pain threshold among patients with hamstring stiffness. Methods : Fourteen participants with hamstrings stiffness were recruited. Interventions were performed 6 times, and each session was for 30 seconds using the three tools. The range of motion, muscle tone, and pain threshold were measured. The order of the use of the three tools was randomly determined. The foam roller was made to move from the bottom of the hip crease to the upper part of the back of the hamstring. Additionally, velocity 5 vibration stimulation was performed on the hamstring using a massage gun. Moreover, vibration stimulation was performed on the hamstring with extracorporeal shock wave therapy 5 minutes, 5 Hz, and 1,500 strokes. The flexibility of the posterior thigh muscle was based on maintaining the knee and hip joints in a 90 ° bend in the supine position. The joint angle of the knee was measured, when the knee was actively extended, at the maximum point where the posterior thigh muscle was stretched. The elasticity of the posterior thigh muscle was measured while the subject was prone and in a relaxed state without any force. Measurements were made at the muscle abdominal area of the semitendinosus muscle of the posterior femur, and the area to be measured was marked with a pen. The measurement of the tenderness threshold of the posterior femur was measured using a tenderness meter(Commander Algometer, J-Tech, USA). The force value at the point at which the pressure sensation change to pain was measured after applying vertical pressure to the posterior femur muscle, which was the halfway point between the ischial tuberosity and the popliteal surface of the subject lying on their stomach. Results : The extracorporeal shock wave therapy increased stiffness and, muscle tone, and caused changes in the pain threshold, whereas the other two tools had no effect on these indices. Conclusion : Extracorporeal shock wave therapy has important effects on range of motion and muscle stiffness and can be used in warmup protocols.

• 대한원격탐사학회지
• /
• 제36권6_1호
• /
• pp.1339-1348
• /
• 2020

식물성플랑크톤은 영양염, 광합성, 탄소순환 등의 측면에서 해양의 생태계를 제어하는데, 해양 환경에 미치는 영향의 정도는 식물성플랑크톤의 크기에 좌우된다. 원격탐사 기술을 기반으로 해양의 식물성플랑크톤 크기 별 생체량을 식별하려는 많은 연구가 있었으며, 그 중 가장 성공적인 접근법 중 하나는 식물성플랑크톤의 크기를 세 등급(micro-plankton;> 20 ㎛, nano-; 2-20 ㎛ 및 pico-; <2 ㎛)으로 구분하여 각 그룹별 엽록소 농도를 추정하는 삼성분 모델(three-component model)이다. 이 연구에서는 동해에서 식물성플랑크톤의 크기 별 생체량 분포를 추정하기 위한 GOCI 자료의 활용 가능성에 대해 검토하였다. 각 크기 별 엽록소 농도(CHL)를 도출하기 위해, 연구지역에서 수 년 동안 수집된 식물성플랑크톤 색소자료를 기반으로 회귀분석을 통해 삼성분 모델의 계수를 산출하였다. 새롭게 산출된 삼성분 모델을 시간 별 GOCI 기반 엽록소 농도 이미지에 적용하여, 전체 엽록소 농도 중 각 식물성플랑크톤 크기 별 생체량이 차지하는 비율을 산출하였다. 또한, 이 결과를 이용하여 동해에서 2013년 여름 대규모 적조가 발생한 시기의 크기 별 엽록소-a 농도 분포를 분석하였다.

• 국제지역연구
• /
• 제12권4호
• /
• pp.67-88
• /
• 2009

남아공의 진실과 화해위원회는 1995년에 설립되어 3년 동안 인종차별주의 체제의 과거사를 정리하였다. 진실과화해위원회의 설립 목적은 기본적으로 진실과 화해를 통한 민주주의 체제로의 이행이었다. 진실과화해위원회의 활동에 대한 평가는 다양하다. 조사에 집중한 법률적 보복으로 평가하는 클러크, 민주주의를 과도기적으로 이행시킨 활동이었다고 평가하는 크로닌, 그리고 단기적인 활동에 머물러 과거사를 제대로 정리하지 못하였다고 평가하는 시민운동단체들도 있다. 그렇지만 진실과화해위원회는 남아공의 민주주의를 이행시키는 과정에서 주요한 역할과 기능을 담당하였다. 첫째, 사회통합의 정체성을 강화시키려 하였다. 둘째, 사회적 하부구조를 개혁시키려 하였다. 셋째, 사회경제적 모순을 약화시키려 하였다. 진실과화해위원회의 역할과 기능이 법무부의 진실과화해국으로 이관된 상태이지만, 남아공의 과거사 정리정책은 몇 가지의 과제를 안고 있다. 첫째, 역사의 복원이라는 차원에서 진실을 지속적으로 규명할 수 있는 국가적·사회적 시스템을 구축할 필요가 있다. 둘째, 사회적 하부구조의 개혁이 위원회의 권고안에 머물거나 부분적이고 일면적인 수준에 머무는 것이 아니라 총체적인 차원의 정부정책으로 수립·집행되어야 한다. 셋째, 남아공의 과거사가 곧 흑인들에 대한 백인들의 노동착취와 긴밀하게 연계되어 있다는 점을 고려하면, 남아공 정부는 흑인들의 노동권리 및 생활권리를 보장할 수 있는 정책을 적극적으로 추진할 필요가 있다. 마지막으로, 국가폭력 및 인권유린의 전체 사건 중에서 약 42%만을 위원회가 조사하였다는 사실에 비추어 보면, 나머지 58%의 사건에 대한 진실규명과 화해조치가 이루어져야 한다.

• Nuclear Engineering and Technology
• /
• 제25권4호
• /
• pp.529-538
• /
• 1993

이전에 제신된 시간 균일적인 경우의 모델［1］에 대한 확장으로 균열암반내 핵종이동에 관한 연속시간 마코프 프로세스를 이용한 통계적 방법에 의한 모델이 제시되었다. 단일 평판 균일을 갖는 암반매질에서 핵종이 균열로부터 알반조직내로 확산 이동하는 경우 더 이상 균열시간적인 마코프 모델을 적용할 수 없으므로 암반으로의 확산항을 시간에 따라 변화하는 과정으로 보아 모델을 제시한 후 기존의 결정론적 해석해와 비교하였다. 통계적모델의 최종 결과는 시간의 함수로서의 상태변수에 대한 기댓값과 그 분산치일 것이다. 핵종의 시간 종속적인 확률분포가 전이강도가 주어질 때 매질내의 특성이 균질하다고 볼 수 있도록 나누어진 암반매질의 각 구획에 대해 주어지게 된다. 이 모델은 매질공간에 대해 불연속적이므로 핵종이동에 영향을 주는 변수들이 쉽게 균열암반이나 다중매질 등과 같은 비균질한 매질에 적용되어 질수 있다. 매질을 나눈 구획수가 수치적 분산에 민감한 것으로 나타났지만 분산계수의 보정에 의해 해석해와 잘 일치되는 것을 알 수 있었다.

• Nuclear Engineering and Technology
• /
• 제55권10호
• /
• pp.3874-3897
• /
• 2023

A high-fidelity computational fluid dynamics (CFD) analysis was performed using the Large Eddy Simulation (LES) model for the lower plenum of the High-Temperature Test Facility (HTTF), a ¼ scale test facility of the modular high temperature gas-cooled reactor (MHTGR) managed by Oregon State University. In most next-generation nuclear reactors, thermal stress due to thermal striping is one of the risks to be curiously considered. This is also true for HTGRs, especially since the exhaust helium gas temperature is high. In order to evaluate these risks and performance, organizations in the United States led by the OECD NEA are conducting a thermal hydraulic code benchmark for HTGR, and the test facility used for this benchmark is HTTF. HTTF can perform experiments in both normal and accident situations and provide high-quality experimental data. However, it is difficult to provide sufficient data for benchmarking through experiments, and there is a problem with the reliability of CFD analysis results based on Reynolds-averaged Navier-Stokes to analyze thermal hydraulic behavior without verification. To solve this problem, high-fidelity 3-D CFD analysis was performed using the LES model for HTTF. It was also verified that the LES model can properly simulate this jet mixing phenomenon via a unit cell test that provides experimental information. As a result of CFD analysis, the lower the dependency of the sub-grid scale model, the closer to the actual analysis result. In the case of unit cell test CFD analysis and HTTF CFD analysis, the volume-averaged sub-grid scale model dependency was calculated to be 13.0% and 9.16%, respectively. As a result of HTTF analysis, quantitative data of the fluid inside the HTTF lower plenum was provided in this paper. As a result of qualitative analysis, the temperature was highest at the center of the lower plenum, while the temperature fluctuation was highest near the edge of the lower plenum wall. The power spectral density of temperature was analyzed via fast Fourier transform (FFT) for specific points on the center and side of the lower plenum. FFT results did not reveal specific frequency-dominant temperature fluctuations in the center part. It was confirmed that the temperature power spectral density (PSD) at the top increased from the center to the wake. The vortex was visualized using the well-known scalar Q-criterion, and as a result, the closer to the outlet duct, the greater the influence of the mainstream, so that the inflow jet vortex was dissipated and mixed at the top of the lower plenum. Additionally, FFT analysis was performed on the support structure near the corner of the lower plenum with large temperature fluctuations, and as a result, it was confirmed that the temperature fluctuation of the flow did not have a significant effect near the corner wall. In addition, the vortices generated from the lower plenum to the outlet duct were identified in this paper. It is considered that the quantitative and qualitative results presented in this paper will serve as reference data for the benchmark.