• The Korean Journal of Physiology and Pharmacology
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• 제20권6호
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• pp.621-628
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• 2016

Hypertension can be caused by various factors while the predominant causes include increase in body fluid volume and resistance in the circulatory system that elevate the blood pressure. Consumption of probiotics has been proven to attenuate hypertension; however, the effect is much strain-dependent. In this study, a newly isolated Lactobacillus casei (Lb. casei ) strain C1 was investigated for its antihypertensive properties in spontaneously hypertensive rats (SHR). Lactic acid bacteria (LAB) suspension of 11 log colony-forming unit (CFU) was given to SHR (SHR+LAB, n=8), and phosphate buffer saline (PBS) was given as a control in SHR (SHR, n=8) and in Wistar rats as sham (WIS, n=8). The treatment was given via oral gavage for 8 weeks. The results showed that the weekly systolic blood pressure (SBP), mean arterial pressure (MAP), diastolic blood pressure (DBP) and aortic reactivity function were remarkably improved after 8 weeks of bacterial administration in SHR+LAB. These effects were mostly attributed by restoration of wall tension and tensile stress following the bacterial treatment. Although not statistically significant, the level of malondialdehye (MDA) in SHR+LAB serum was found declining. Increased levels of glutathione (GSH) and nitric oxide (NO) in SHR+LAB serum suggested that the bacterium exerted vascular protection through antioxidative functions and relatively high NO level that induced vasodilation. Collectively, Lb. casei strain C1 is a promising alternative for hypertension improvement.

• 전자공학회논문지
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• 제51권6호
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• pp.228-236
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• 2014

견인 선배열 소나는 해양이라는 유체에서 작동하기 때문에 그 형상이 왜곡되고, 특히 견인 함정이 회전하는 경우 형상이 심하게 변형된다. 이러한 경우 선배열이 갖는 빔 패턴 형성은 제한되며, 이로 인한 신호 대 잡음비 등의 성능 저하를 야기한다. 본 논문에서는 2단 최소자승법에 기초한 개선된 2단 최소자승법 알고리즘을 제안하였으며, 해양에서 운용되는 선배열의 형상을 변침각도로 모델링하여 알고리즘을 적용하였다. 변침각도와 주엽의 위치를 변경하면서, 알고리즘별 조향 빔의 신호 대 잡음비를 분석하였다. 그 결과 제안한 알고리즘이 다른 알고리즘보다 2dB 정도 성능이 향상되었으며, 비교적 일정한 빔 패턴을 형성하였다.

• 한국환경복원기술학회지
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• 제21권5호
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• pp.17-28
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• 2018

Cyclonic-dissolved air flotation(Cyclonic-DAF), an advanced form of pressure flotation, applies a structure that enables the forming of twirling flows. This in turn allows for suspended matter to adhere to microbubbles and float to the surface of a treatment tank during the process of intake water flowing through a float separation tank. This study conducted a lab-scale test and pursued geometrical modeling using computational fluid dynamics(CFD) to establish a pilot scale design. Based on the design parameters found through the above process, a pilot cyclonic-DAF system($10m^3/hr$) for removing algae was created. Upon developing the pilot-scale cyclonic-DAF system, a type of algae coagulant(R-119) was applied as the coagulant to the system for field testing through which the removal rates of chlorophyll-a and cyanobacteria were evaluated. The chlorophyll-a and harmful cyanobacteria of the raw water at region B, the field-test site, were found to be $177.9mg/m^3$ and 652,500cells/mL respectively. Treated waters applied with 60mg/L and 100mg/L of algae coagulant presented removal efficiencies of approximately 95% and 97%, respectively. The cyanobacteria cell number of the treated waters applied with 60mg/L and 100mg/L of algae coagulant both that were equal to or less than 1,000cells/mL and were below attention level criteria for the issuance of algae boundary.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2000년도 춘계수산관련학회 공동학술대회발표요지집
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• pp.505-505
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• 2000

Perkinsus sp. has been identified as responsible organism for the decrease in Manil clam production along the west and south coast of Korea. Monthly investigation on infection intensity and pathology of Perkinsus infected Manila clam population was carried out in Komsoe Bay located in the west coast during February and December 1999. About one hundred clams were collected each month for the analysis. Infected clams were incubated in fluid thioglycollate media over a week, stained with iodine solution, digested with 2M NaOH and the number of Perkinsus present in an individual recorded. Histological slides were also prepared from infected clams and their pathologic symptoms were examined using a microscope. Trophozoites of Perkinsus sp. were dominantly distributed on gills and epithelia of digestive glands however a few numbers could be detected at siphons and foot tissues. Heavily infected clams often exhibited white spots on mantle and foot tissues due to the inflammatory reaction of the hemocytes, forming nodules. Trophozoites were also found along the connective tissues of follicles during spawning season indicating that Perkinsus sp. may disturb reproduction of the clam. Total number of Perkinsus sp. in an individual clam varied from none to 9, 550, 000 with a monthly mean of 279, 663 to 2, 198, 558 during the course of study. The number of Perkinsus sp. in the clam was found to lowest durin July and August when unusually low salinity was recorded in this area due to the heavy rain. Highest monthly infection intensity in terms of total number of Perkinsus sp. i clam was observed in February, when water temperature recorded as lowest during the study. Small size of clams with shell length of ten mm or less were not infected with Perkinsus sp. It was concluded that Perkinsus infection in Manila clam is in pa controlled by changes in salinity and clam growth; low salinity environment minimize infection intensity while tile clams get more Perkinsus as they grow.

• 자원환경지질
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• 제36권6호
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• pp.407-413
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• 2003

알칼리 교대암내에 배태되는 압동 Nb-Ta 광상의 지질은 상부원생대의 퇴적암류와 이를 관입분포하는 고생대 후기에서 중생대 초기의 평강암군에 속하는 호암산 관입암체(알칼리 섬장암류), 쥬라기의 흑운모화강암 및 제4기의 현무암으로 구성된다. 알칼리 섬장암류는 각섬석-휘석 섬장암, 각섬석-흑운모 섬장암, 흑운-하석 섬장암, 흑운모 섬장암 및 석영-각섬석-휘석 섬장암 등을 포함한다. 후기 마그마 단계에서 수반되는 알칼리 교대작용에 의해 형성된 알칼리 교대암은 호암산 관입암체의 남쪽 가장자리를 따라 띠모양이나 불규칙한 맥상 및 렌즈상으로 Nb-Ta 광체를 이루고 있다. 산출되는 광석광물은 파이로크롤과 저어콘을 비롯하여 극소량의 콜럼바이트, 퍼규소나이트, 자철석, 형석, 휘수 연석, 티탄철석, 티타나이트, 인회석 및 모나자이트 등 이다. Nb, Ta, 희토류 및 방사성 원소(Th, U)를 함유하는 파이로크롤은 (1) 부화된 Ta, U 및 Ce, (2) 낮은 함량의 Ta 및 F (3) Th 또는 Ba의 부화 등으로 특징된다. 지화학적 특징과 광석의 구조 및 광물의 산출 특성으로 미루어 광화작용이 알칼리성 광화유체의 교대작용에 따른 것임을 알 수 있다.

• Wind and Structures
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• 제20권5호
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• pp.643-660
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• 2015

The wind tunnel test of large-scale sectional model and computational fluid dynamics (CFD) are employed for the purpose of studying the aerodynamic appendices and mechanism on suppression for the vortex-induced vibration (VIV). This paper takes the HongKong-Zhuhai-Macao Bridge as an example to conduct the wind tunnel test of large-scale sectional model. The results of wind tunnel test show that it is the crash barrier that induces the vertical VIV. CFD numerical simulation results show that the distance between the curb and crash barrier is not long enough to accelerate the flow velocity between them, resulting in an approximate stagnation region forming behind those two, where the continuous vortex-shedding occurs, giving rise to the vertical VIV in the end. According to the above, 3 types of wind fairing (trapezoidal, airfoil and smaller airfoil) are proposed to accelerate the flow velocity between the crash barrier and curb in order to avoid the continuous vortex-shedding. Both of the CFD numerical simulation and the velocity field measurement show that the flow velocity of all the measuring points in case of the section with airfoil wind fairing, can be increased greatly compared to the results of original section, and the energy is reduced considerably at the natural frequency, indicating that the wind fairing do accelerate the flow velocity behind the crash barrier. Wind tunnel tests in case of the sections with three different countermeasures mentioned above are conducted and the results compared with the original section show that all the three different countermeasures can be used to control VIV to varying degrees.

• 한국통신학회논문지
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• 제25권7A호
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• pp.1006-1016
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• 2000

본 논문은 뇌의 자기공명영상에서 백질과 회백질 및 뇌척수액을 분리하고 각각의 체적을 산철하기 위한 것이다. 본 연구는 먼저 뇌의 자기공명영상에서 영상의 배경을 제거한 후 외피 및 지방층으로부터 뇌 영역 전체를 분리하였으며, 부분체적의 문제(partial volume artifact)에 의해 명암 값의 번짐 현상을 보이는 뇌의 내부 영역에서 자기 공명영상의 생성원리를 근거로 명암 값의 산술적인 해석을 통해 원래의 단면 안에 존재하던 각 성분의 부분체적을 산출하였다. 산출된 백질과 회백질 및 뇌척수액의 부분체적은 번짐 현상을 보이는 자기공명영상에서 각 성분을 분리하기 위한 판별값을 경정하기 위해 사용되었고, 최종적으로 백질과 회백질 및 뇌척수액의 체적을 산출하도록 하였다. 본 연구는 뇌의 위축을 보이지 않는 정상인의 자기공명영상을 대상으로 하였으며, 향후 이러한 연구 결과는 알쯔하이머 병이나 뇌성마비등과 같은 퇴행성 뇌 질환 환자의 뇌 위축정도를 객관적으로 진단하는 방법으로 사용 될 수 있다.

• 암석학회지
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• 제20권1호
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• pp.61-75
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• 2011

제주도 신산리에 분포하는 알칼리현무암에 포획된 하즈버가이트와 레졸라이트 맨틀 포획암에는 조직적으로 뚜렷하게 구별되는 이차 사방휘석이 산출되어 다양한 정도로 교대작용을 받았음을 지시한다. 이차 사방휘석은 감람석의 가장자리나 입자경계에 형성되어 있으며, 코로나 혹은 포이킬리틱 조직을 보여준다. 이러한 조직은 감람석이 소모되면서 사방휘석이 만들어진 것을 나타내는 것으로, 실리카가 포화된 유체 또는 멜트가 관여한 교대작용이 있었음을 지시한다. 제주도의 조구조 특성, 맨틀 포획암의 조직 그리고 주원소 조성에 의하면 이 실리카가 포화된 멜트나 유체는 수렴경계에 형성되는 섭입대에서 유래된 것으로, 제주도 하부 상부맨틀 암석권은 제주도가 형성되기 이전에 맨틀웨지 환경에서 광범위한 실리카부화작용을 경험하였음을 시사한다.

• 한국기계가공학회지
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• 제17권6호
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• pp.144-150
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• 2018

In this study, the freezing process of L-shaped pipe exposed to the outside was investigated numerically by considering the mushy zone of freezing water. From the numerical results, it was found that the flow was outwardly directed due to the influence of the L-shaped bending part in the outside exposed part of the pipe, and the ice was formed in the shape of longitudinal corrugation on the wall surface of the pipe after the bending part. It is confirmed that this phenomenon is caused by the venturi effect due to the freezing as seen in connection with the velocity distribution in the pipe. It is found that the remelting phenomenon at the end of the freezing section occur simultaneously during the process of forming the ice in the pipe section. In regard of the factors affecting freezing, it was found that the thickness of the freezing layer is increased as the exposed pipe surface temperature is decreased, and the pipe surface temperature had a significant effect on the change of the freezing layer thickness. At the same time, it was found that the freezing layer becomes relatively thin when the water inflow rate is increased. This phenomenon was caused by reducing the exposure time of freezing water due to the vigorous flow convection of the water fluid.

• 대한구강악안면병리학회지
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• 제42권6호
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• pp.189-198
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• 2018

A 31 years old female had been suffered from a bony swelling in right premolar region of the mandible for 12 years, recently grown rapidly. A fistula tract developed on the right anterior mandibular border, but the lesion was relatively asymptomatic. In the radiological examination, the tumor mass was irregularly mixed with radiolucent and radiopaque areas, forming multiple cystic spaces. Under the diagnosis of calcifying odontogenic cyst, the mandibular mass was resected and examined pathologically. After decalcification, the dissected tumor mass showed multiple small cystic spaces and calcifying fibrous tissue, mimicking calcifying odontogenic cyst or ameloblastoma. Histological observation showed many calcifying cementoid materials and ossifying trabeculae. The cystic spaces were turned out to be dilated vascular channels lined by endothelial cells, containing plasma fluid. However, the main lesion was diagnosed as cemento-ossifying fibroma (COF), and the atypical vascular channels were greatly dilated and gradually expanded the whole tumor mass. The present COF was examined through immunohistochemical (IHC) array, and investigated for tumor cell characteristics, exhibiting abnormal ossification and aneurysmal cystic changes. IHC array disclosed that the tumor cells grew progressively in the lack of apoptosis, and that they showed lower expression of RUNX2 than BMP-2, RANKL, and OPG, and increases of protein expression in $HIF-1{\alpha}$, VEGF-A, and CMG2. These data suggested that the reduced expression of RUNX2, osteoblast differentiation factor, be relevant to abnormal ossification of COF, and that the consistent expressions of angiogenesis factors be relevant to de novo angiogenesis in COF, subsequently resulted in aneurysmal cystic changes.