• 자원환경지질
• /
• 제50권6호
• /
• pp.487-495
• /
• 2017

경상북도 군위군 부계면 동산리에 위치한 팔공산 도립공원의 한 등산로에는 '북바위'라 불리는 화강암질 암체가 존재한다. 이 암체에서는 특정 부위를 타격했을 때 북과 같은 타악기에서 발생하는 공명음과 유사한 공명 현상이 발생한다. 이러한 소리를 발생시키는 공명 현상의 지질학적 원인으로는 화강암 생성 과정에서 내부 기체가 빠져나가면서 형성된 공동이 존재할 가능성과 생성 이후 지질학적으로 오랜 기간 동안 겪은 풍화 작용에 의한 박리 현상에 기인할 가능성이 있다. 이 연구에서는 북바위 화강암체에서 공명을 일으키는 내부구조를 보다 정밀하게 파악하기 위하여 비파괴 탐사기법인 지하투과레이더 탐사를 수행하였다. 지하투과레이더 탐사 기법은 수 MHz에서 수 GHz범위의 고주파 레이더 신호를 탐사 대상의 표면에서 내부로 투과시켜 물성의 변화 혹은 불연속면이 존재하는 곳에서 반사되는 반사파들의 진폭을 기록하여 해석한다. 화강암체 최외곽 표면에 존재할 것으로 추정되는 내부구조를 영상화하는 것이 연구 목표이므로 탐사 심도는 얕지만 고해상도 자료 획득이 가능한 1 GHz 레이더를 이용하였다. 3차원 내부구조 영상화를 위하여 암체 표면에 격자를 구성하여 탐사를 수행하였다. 탐사 자료 해석 결과 북소리와 같은 공명이 일어나는 지점들에서 강한 반사 레이더파가 관찰되었으며, 위치에 따라 균열과 공동에서의 반사파 특징이 모두 관찰되었다. 또한 공명이 가장 크게 일어나는 지점에서 두 불연속면이 교차하면서 만들어진 공동 구조가 관찰되었다. 주어진 균열 구조를 반영하는 수치 모델을 적용하여 계산한 결과, 공명 현상에는 화강암의 박리 작용에 의한 균열과 암석 생성 당시의 미아롤리틱 구조가 함께 기여한 것으로 보인다. 이와 같이 일반 대중의 흥미를 유발하는 지질 구조체에 대한 비파괴 탐사 기반의 영상화 연구 활동은 지구과학 대중화에 많은 기여를 할 수 있을 것으로 판단된다.

• Journal of Periodontal and Implant Science
• /
• 제44권1호
• /
• pp.33-38
• /
• 2014

Purpose: Autogenous bones are frequently used because of their lack of antigenicity, but good osteoconductive and osteoinductive properties. This study evaluated the biological behavior of perforated and nonperforated cortical block bone grafts. Methods: Ten nonsmoking patients who required treatment due to severe resorption of the alveolar process and subsequent implant installation were included in the study. The inclusion criteria was loss of one or more teeth; the presence of atrophy of the alveolar process with the indication of reconstruction procedures to allow rehabilitation with dental implants; and the absence of systemic disease, local infection, or inflammation. The patients were randomly divided into two groups based on whether they received a perforated (inner surface) or nonperforated graft. After a 6-month healing period, a biopsy was performed and osseointegrated implants were installed in the same procedure. Results: Fibrous connective tissue was evident at the interface in patients who received nonperforated grafts. However, full union between the graft and host bed was visible in those who had received a perforated graft. Conclusions: We found that cortical inner side perforations at donor sites increased the surface area and opened the medullary cavity. Our results indicate an increased rate of graft incorporation in patients who received such perforated grafts.

• 대한한방내과학회지
• /
• 제30권2호
• /
• pp.399-409
• /
• 2009

Objectives : The aim of this study was to experiment the antitumor activity of Agrimonia pilosa Ledebour (APL) in human stomach cancer (AGS) cell lines (in vitro) and male C57BL/6J mouse (in vivo). Methods : The effects of the ethanol extract from the plant on several transplantable rodent tumors were investigated in vitro by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxy phenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay. DNA content analysis and Western blot analysis. Agrimonia pilosa Ledebour (APL) was given to rats with Lewis Lung Carcinoma (LLC) cells. The experimental rats were divided into 3 groups in vivo. Saline was injected into the abdominal cavity in the first group, 50 mg/kg APL was injected into the abdominal cavity in the second group and 100 mg/kg was injected into the abdominal cavity in the third group. After that, we checked their tumor volume periodically. Results : At first, human gastric cancer (AGS) cell lines (in vitro) showed decreased cell viability, and increased $sub-G_1$ contents. When we experimented rat intestinal epithelial (RIE)l as same condition, this result didn't show. With this, compared to normal cells, Agrimonia pilosa Ledebour (APL) led selectively to the extinction of cells only in human gastric cancer. Moreover, we showed that the traditional herbal medicine APL induced caspase-dependent apoptosis in AGS cells. Next, APL inhibited the growth of LLC-bearing mouse tumor. However, we could not verify APL induced caspase-dependent apoptosis in LLC-bearing mouse tumor. Conclusions : The roots of Agrimonia pilosa Ledebour (APL) contain some antitumor constituents.

• Korean Chemical Engineering Research
• /
• 제49권1호
• /
• pp.47-55
• /
• 2011

K사의 고무 사출성형에 있어서 애로사항인 등속조인트 부트(boots)의 크 (crack) 발생 등의 문제점을 해결하기 위하여, 상용 CAE 프로그램인 MOLDFLOW(Ver. 5.2)를 이용한 전산모사를 수행하여 적정금형설계를 도출하고 적정작업조건을 구축하였다. 그 결과 크 의 발생 원인은 크 이 발생하는 위치에 형성되는 weld 및 meld line의 형성 때문이고, 또한 크 이 발생하는 위치에서의 가류(curing)가 불완전한 것이 확인되었다. 이와 같은 weld 및 meld line의 형성을 방지하기 위해서 게이트(gate)의 위치를 변경하고 최적위치에 설계함으로써, 유동선단(melt front)의 충돌 또는 수지흐름의 만남을 최소화하는 충전패턴(fill pattern)을 형성하고 부트 안쪽 하단의 크 발생을 방지하였다. Weld 및 meld line과 에어트랩(air trap) 불량이 가장 큰 게이트 위치는 각각 최적 게이트위치를 기준으로 서로 정반대 방향임이 관찰 되었다. 한편 몰드(mold)의 온도를 $170^{\circ}C$로 유지하게 함으로써 크 이 발생했던 위치에 가류조건을 만족시켰다.

• Applied Microscopy
• /
• 제18권2호
• /
• pp.91-101
• /
• 1988

The ultrastructure of the sac and tail portion of the large ampullate gland and production of the silk materials in the orb web spider, Nephila clavata L. Koch, are studied with electron microscope. Large ampullate glands, the largest glands among the seven kinds of silk glands in this species, are composed of three parts which are the excretory duct, the storage sac and the convoluted tail. The wall of the sac is composed of a single layer of columnar epithelial cells. In the cytoplasm of these cells several kinds of the secretory granules, which are commonly associated with the rough endoplasmic reticula and had characteristic crystalloid, are seen. According to the morphology and internal textures of these granules, the sac portion is subdivided into proximal(connected with the convoluted tail) and distal(connected with excretory duct) portion. Between these two portions, the proximal portion is longer than the distal by four times. Silk materials, being synthesized to the shape of secretory granules, within the glandular epithelial cell of the tail portion are released to the inner cavity by the mechanism of the eccrine secretion. These secretory granules are originated from the rough endoplasmic reticula of the glandular epithelial cells, whereas no Golgi complexes has been found in any of the cells which have been examined.

• Tribology and Lubricants
• /
• 제12권4호
• /
• pp.28-34
• /
• 1996

The lubrication characteristics of high-speed ball bearings have been investigated empirically using 45mm bore split inner ring ball bearings employed in small industrial gas turbine engines with oil-jet lubrication method. For the close structural simulation, experiments carried out with bearing mounting supports of real engines, such as bearing housings and oil nozzle assemblies with squeeze film dampers. Thus the results of tests can be directly applied to the design and the development of gas turbine engines. Testing was done by varying operating speeds, axial load on bearings, and lubricant flow rates. During testing, the temperature of bearing at outer-ring face, the power consumption of the driving motor, and the rotating resistance of the bearing were measured. From this study, the representative factors for lubrication characteristics at high speed was found, and the most important one was not operating speed but axial load up to 1.95 million dmN speed and 2969 N axial load. Furthermore, the detailed variation of the rotational resistance of the bearing could be visualized by measuring the change of the radial load under the bearing supports. The rotational resistance consists of the frictional resistance and the bearing-cavity oil resistance.

• 한국응급구조학회지
• /
• 제10권1호
• /
• pp.23-39
• /
• 2006

In Korea, There are many disasters, like the collapse of Sampung department store, the strike of severe typhoon 'Rusa' and the subway tragedy in Taegu, because of global warming, urbanization, high-density and high-rise of buildings. So, the government made 'The Framework Act' on the safe and management of disaster and 'The National Emergency Management Agency' was established. But emergency medical service systems in Korea is not growing so much. The purpose of this research is to give basic data for the development of emergency medical service systems in Disaster by comparing of disaster management systems and emergency medical systems among the nations of the world, analysing emergency medical systems in disaster in Korea and suggesting some improvement methods. The improvment methods are like this ; First, establishing the National Disaster Medical System in Korea, making the good triage by EMT, expansion of EMT's working area, developing protocols and framing of medical director increasing the working force of EMT, broad inner cavity of ambulance for treatment of patientent, supplement of professional equipments, active using of helicopters are needed in prehospital are. Second, equal establishment of emergency medical center and increase of working force of emergency medical team are needed in hospital area. Finally, enforcement of the dispatcher's qualification, smooth communication among EMSS systems and actualization of medical direction through screen are needed in the Telecommunication system.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 춘계학술대회
• /
• pp.668-671
• /
• 2007

A numerical study was conducted on a simplified model of a high-temperature solar receiver which incorporates liquid-metal heat pipe. The objective of this paper is to compare the isothermal characteristics of the heat pipe receiver with the conventional receiver utilizing convection of molten salt as heat carrier. The solar receiver was assumed to be subject to a concentration ratio between 50 and 1,000 to supply high-temperature heat to a stirling engine for electric power generation. For simplicity of the analysis, a cylindrical geometry was assumed and typical dimensions were used based on available literature. The heat pipe had a shape of double-walled cavity and the working fluid was a sodium. The analysis was performed assuming that the radiation heat flux on the inner walls of the receiver was uniform, since the focus of this study was laid on the comparison of the conventional type and heat pipe type receiver. The results showed that the heat pipe type exhibited superior performance when the operating temperature becomes higher. In addition, to explore the advantage of the heat pipe receiver, the channel shape and dimensions should be adjusted to increase the heat transfer area between the wall and the heat trnasfer medium.

• Clinical and Experimental Reproductive Medicine
• /
• 제41권4호
• /
• pp.174-177
• /
• 2014

Adenomyosis is a common gynecological disorder characterized by the presence of endometrial glands and stroma deep within the myometrium associated with myometrial hypertrophy and hyperplasia. Focal uterine infarction after IVF-ET in a patient with adenomyosis following biochemical pregnancy has not been previously reported, although it occurs after uterine artery embolization in order to control symptoms caused by fibroids or adenomyosis. We report a case of a nulliparous woman who had uterine adenomyosis presenting with fever, pelvic pain and biochemical abortion after undergoing an IVF-ET procedure and the detection of a slightly elevated serum hCG. Focal uterine infarction was suspected after a pelvic magnetic resonance imaging demonstrated preserved myometrium between the endometrial cavity and inner margin of the necrotic myometrium. This case demonstrates that focal uterine infarction should be considered in the differential diagnosis of acute abdominal pain, vaginal bleeding and infectious signs in women experiencing biochemical abortion after an IVF-ET procedure.

• 대한수의학회지
• /
• 제8권2호
• /
• pp.84-91
• /
• 1968

The arteries in and under the brain of the fowl were invesitigated. Arteries of the brain were injected with neoplen latex into the arteria carotis communis. Those were fixed in 10--- formalin. After fixation, those brain were carefully removed from the cranial cavity doing not wound the arteries of the brain. The results of observation on the arterial supply under the brain surface were essentially the same as those obtained by Hofmann Shiina and Mjyata, Kaku, and Kithoh. The nomenclature of the arteries used by other authers were written in the discussion. In this observation, several conclusions were obtained. 1. In the arteries under the brain of the fowl, their front anastomoses forming the circle of Willis under the brain surface of the mammalia were not seen in all brain. 2. It is very difficult to indicate so called A. cerebri anterior as only one artery ramus. 3. Artery distribution of the two-third in the fissura longitudinal cerebri surface originate from on1y one side in the left or right A. cerebri posterior, and origins of the right side were man number than left. 4. The origin of the A. basilaris originate from only one side R. posterior, therefore their origin were more left than right. 5. There is Rami arteries that branch from A. ethmoidalis to Chiasma opticum in all cases.