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검색결과 262건 처리시간 0.02초

건축용 내화 재료로서의 포비성 알칼리 규산염의 특성에 관한 연구 (Properties of Intumescence Alkali Silicates for Building Fire-Resistant)

  • 강현주;강승민;송명신;김영식;박종헌
    • 공업화학
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    • 제20권4호
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    • pp.416-422
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    • 2009
  • 강구조 건축물은 화재시 화염을 차단하기 위한 목적으로 내화재료를 사용하고 있다. 일반적으로 모든 건축 구조용 재료는 시간이 경과할수록 초기의 성능이 열화되기 때문에 이들의 유지관리가 필요하다. 내화 피복재는 건축물의 화재에 대한 내구성능은 내화피복재에 의존하기 때문에 건축물에서 매우 중요한 재료라 할 수 있다. 본 연구에서는 내화피복재로서의 알칼리 규산염의 합성 및 합성한 알칼리 규산염의 물성에 대해 연구하였는데, 알칼리 규산염의 종류로는 potassium silicate, sodium silicate, lithium silicate으로 하였으며, 기본적으로 몰 비율의 변화를 주어 합성하였다. 합성한 알칼리 규산염의 내화특성을 확인하기 위하여 용해도 포비도, 열 분석, 결정학적 분석, 차열성능 및 차염성능에 대해 시험하였다. 연구결과, 합성한 알칼리 규산염의 용해도, 포비도는 칼륨 실리케이트, 소디움 실리케이트, 리튬실리케이트의 순서로 나타났으며, 열분석에 의한 무게 손실은 소디움 실리케이트와 리튬 실리케이트가 칼륨 실리케이트 보다 큰 것으로 나타났다. 또한 화재 시 가장 중요한 차열성능과 차염성능에 대해KS 기준을 만족하는 것은 소디움 실리케이트 3.3 몰 배합으로 나타났는데, 내화피복재로서 우수한 성능을 발휘하였다.

야관청혈탕이 고지방식이로 유도된 흰쥐의 비만 억제에 미치는 영향 (Effect of Yagwan-cheunghyeoltang on Obesity in Rats Induced by High Fat Diet)

  • 박상우;조충식;김철중
    • 대한한방내과학회지
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    • 제32권2호
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    • pp.170-187
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    • 2011
  • Background : Obesity, the syndrome caused by a high fat diet, is a disease. At the same time, obesity causes diabetes mellitus, hyperlipidemia, and cardiovascular disease. Recently, its prevalence rate is increasing. Yagwan-cheunghyeoltang (YCT) used in this experiment is the prescription of Yagwanmoon added to Cheunghyeol-tang which is reported to be very effective in weight loss controlling and serum cholesterol. It is also reported that Yagwanmoon has significant antioxidant effects and YCT has a significant effect on blood glucose control. Objectives : This study was conducted to experimentally evaluate the effects of YCT on obesity in rats induced by high fat diet. Methods : The experiment was conducted with 4-week-old male rat s divided into 5 groups. They were a normal diet group, a high fat diet group, a positive drug control group, a 1% YCT group, and a YCT 3% group, and were tested for eight weeks. After four weeks of inducing obesity by a high fat diet, rats were allowed to lose weight by following the normal diet group, approximately 30% compared with 10 rats in each group were determined as still obese. Changes in body weight and organ weight and serum cholesterol, triglyceride, glucose-density, low density lipoprotein cholesterol, antioxidant activity were checked. Results : In the experimental groups, we observed weight loss and visceral fat reduction, improvement of liver function, reduction of serum glucose, activation of HMG-CoA reductase inhibitor, reduction of concentrations of leptin and it showed a significant effect on antioxidants and lipid peroxidation. Conclusions : YCT has significant effects on the regulation of hyperlipidemia and lipid peroxidation associated with obesity and has significant effects on, antioxidants and lipid peroxidation, too. Additional clinical studies are needed.

Study on a Dynamic master system for Controller Area Network

  • Won, Ji-Woon;Hong, Won-Kee;Lee, Yong-Doo
    • 한국정보기술응용학회:학술대회논문집
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    • 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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    • pp.147-151
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    • 2005
  • CAN(Controller Area Network) is a simple and efficient network system for real time control and measurement. As it is not only good at error detection but also strong in electromagnetic interference, CAN has been widely used all over the industries. Basically, CAN needs a master node in charge of sensor data collection, node scheduling for data transmission to a monitoring system and error detection. According to the number of mater nodes, the CAN system is classified into two type of master system. One is a single master system that has only one master node and the other is a multi-master system where any sensor node can become a master node depending on the system's conditions. While it has the advantage of its fault tolerance, the multi-master system will suffer form the overall performance degradation when a defect is found in the master node. It is because all sensor nodes pertaining to a defective master node lose their position. Moreover, it is difficult and expensive to implement. For a single master system, the whole system will be broken down when a problem happens to a single master. In this paper, a dynamic master system is presented that there are several sub-master nodes of which basic functions are those of other sensor nodes at ordinary times but dynamically changed to replace the failing master node. An effective scheduling algorithm is also proposed to choose an appropriate node among sub-master nodes, where each sub-master node has its precedence value. The performance of the dynamic master system is experimented and analyzed.

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Sweet BV의 rat를 이용한 단회 근육시술 독성시험 (Study of single dose test of Sweet Bee Venom in rats)

  • 김영진;임청산;권기록
    • 대한약침학회지
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    • 제12권4호
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    • pp.5-32
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    • 2009
  • Objectives: This study was performed to analyse single dose toxicity of pure melittin(Sweet Bee Venom-Sweet BV) extracted from the bee venom by utilizing protein isolation method of gel filtration. Methods: All experiments were conducted at Biotoxtech, a non-clinical studies authorized institution, under the regulations of Good Laboratory Practice (GLP). Six weeks old female Sprague-Dawley rats were chosen for the pilot study and determined 30㎎/㎏ which is 4285 times higher than the clinical application dosage as the high dosage, followed by 15 and 7.5㎎/㎏ as mid and lose dosage, respectively. Equal amount of excipient to the Sweet BV experiment groups was administered as the control group. Results: 1. No mortality was witnessed in all of the experiment groups. 2. Hyperemia and movement disorder were observed around the area of administration in all groups, and higher occurrence in the higher dosage groups. Hyperemia and movement disorder diminished with elapsed time. 3. For the weight measurement, male groups showed larger reduction in weight in accordance with higher dosage. Female groups didn't s how significant changes. 4. To verify abnormalities of organs and tissues, cerebellum, cerebrum, liver, lung, kidney, and spinal nerves were removed and conducted histological observation with H-E staining. No abnormalities were detected in any of organs and tissues. 5. One female rat in the 30㎎/㎏ group had amputated toe near the administered area and histopathological finding was hemorrhage with inflammation. This is presumed as a secondary infection after the administration of Sweet BV. Conclusion: Above findings suggest Sweet BV is relatively s safe treatment medium. Further studies on the subject should be conducted to yield more concrete evidences.

Fast Search with Data-Oriented Multi-Index Hashing for Multimedia Data

  • Ma, Yanping;Zou, Hailin;Xie, Hongtao;Su, Qingtang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제9권7호
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    • pp.2599-2613
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    • 2015
  • Multi-index hashing (MIH) is the state-of-the-art method for indexing binary codes, as it di-vides long codes into substrings and builds multiple hash tables. However, MIH is based on the dataset codes uniform distribution assumption, and will lose efficiency in dealing with non-uniformly distributed codes. Besides, there are lots of results sharing the same Hamming distance to a query, which makes the distance measure ambiguous. In this paper, we propose a data-oriented multi-index hashing method (DOMIH). We first compute the covariance ma-trix of bits and learn adaptive projection vector for each binary substring. Instead of using substrings as direct indices into hash tables, we project them with corresponding projection vectors to generate new indices. With adaptive projection, the indices in each hash table are near uniformly distributed. Then with covariance matrix, we propose a ranking method for the binary codes. By assigning different bit-level weights to different bits, the returned bina-ry codes are ranked at a finer-grained binary code level. Experiments conducted on reference large scale datasets show that compared to MIH the time performance of DOMIH can be improved by 36.9%-87.4%, and the search accuracy can be improved by 22.2%. To pinpoint the potential of DOMIH, we further use near-duplicate image retrieval as examples to show the applications and the good performance of our method.

전북지역 일부 여대생의 체형인식도 및 신체질량지수와 식생활 행동과의 관련성 (The Relationship of Food Behaviors with Body Image and BMI of Female College Students in Jeonbuk Province)

  • 김병숙;이영은
    • 한국생활과학회지
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    • 제9권2호
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    • pp.231-243
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    • 2000
  • This study was conducted to investigate the relationship between body image and BMI with satisfaction of own body image, snack intake practices, food intake practices and weight control practices of 226 female college students in Jeonbuk province using questionnaire. The results were summarized as follows : 1. The average height, weight and BMI was 162.08cm, 52.02kg and 19.78, respectively. The average ideal body weight of the subjects was 48.92kg. Ninety percent of the subjects was dissatisfied with their body image. The degree of dissatisfaction was higher in the group who recognized themselves as fat. Most of subjects wanted to lose weight, but as the group having a recognition of thin body image significantly wanted to gain weight (p<0.001). 2. The subjects preferred fruits and juices for snack. The more subjects recognized themselves as fat, the more they restricted snack intake (p<0.05). 3. The rate of skipping meal tends to increase. The subjects did not intake balanced meals and skipped breakfast most (20.7%). The number of food groups taken at breakfast, lunch and dinner was 1.84, 2.25 and 2.55, respectively and the most variable food groups were taken at dinner(p<0.001). Dairy food group intake was low. The duration of meal time was longer in the underweight group by BMI regardless of body image recognition (p<0.05). 4. The weight controlling method was concentrated mostly on decreasing food intake. The more subjects recognized themselves as fat, the more they tried to control weight (p<0.001). Even though 59.5% of the subjects with no weight control experience had no future weight control plans, 50% of the group who recognized themselves as normal or fat did not want to control weight in the future (p<0.01). These results suggest that nutrition education programs and correction programs of food behaviors and weight control should start from focusing on the accurate recognition of body image for college female students.

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움직임 벡터의 정보 숨김을 이용한 H.264/AVC의 향상된 오류 검출 방법 (Improved Error Detection Scheme Using Data Hiding in Motion Vector for H.264/AVC)

  • 고만근;서재원
    • 한국콘텐츠학회논문지
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    • 제13권6호
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    • pp.20-29
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    • 2013
  • 제한된 통신 채널을 통한 실시간 전송을 위해 비디오 데이터의 압축이 필요하다. 압축된 영상 비트열은 전송 중에 발생되는 오류에 아주 민감하다. 전송 과정에서 오류가 발생된 패킷을 받게 되면, 복호기에서는 현재 입력되는 프레임을 잘못 재구성하게 되고 영상의 시공간적 특성에 의해 연속되는 프레임으로 전파된다. 이런 복호 영상의 화질 저하를 줄일 수 있는 방법으로 오류 검출과 오류 은닉이 있다. 이 논문에서는 오류 검출률을 높이기 위해 정보 숨김을 이용한 새로운 오류 검출 방법을 제안한다. H.264/AVC의 화면간 예측에서 발생하는 각 매크로블록의 움직임 벡터의 차분값에 특정한 정보를 숨겨 부호화하였다. 복호기에서는 전송받은 특정 정보의 체크를 통해 오류의 위치를 쉽게 찾아낼 수 있도록 하였다. H.324M 모바일 실험 도구를 이용한 실험 환경을 통해 제안한 알고리즘이 PSNR과 주관적 화질 측면에서 좋은 성능을 보임을 확인하였다.

새로운 백금 착체(II) 화합물의 흰쥐 혈장에서 대사체 확인 (Identification of Major Metabolites of New Platinum(II) Complexes in Rats)

  • 김종환;조요나;노영수;서성훈;정지창;장성구;이규홍;이주한;이경태
    • Journal of Pharmaceutical Investigation
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    • 제28권3호
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    • pp.171-175
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    • 1998
  • KHPC-002 $[(trans-l-diaminocyclohexane-bis-l,2(diphenylphosphinoethane)platinum)\;{\cdot}2NO_3]$ and $KHPC-006[(cis-diaminocyclohexane-bis-1,2(diphenylphosphinoethane)platinum)\;{\cdot}2NO_3]$ were synthesized as candidates for third platinum antitumor agent. Before their pharmacokinetic study, we optimized the analytical condition with HPLC and identified the major metabolites in the rat plasma. HPLC analysis by $C_{18}$ reverse-phase column showed that standard peak of both compounds appeared rapidly at around 1 minutes, whereas metabolites of KHPC-002 and KHPC-006 which were extracted from plasma after single I.V. administration in rats or incubation for 24 hr at $37^{\circ}C$ showed retention time of $10{\sim}11$ minutes. These metabolites were identified as the major compound by Matrix Associated Laser Deposition/Ionization (MALDI), which only lose the 2 molecules of $NO_3$. Based on these results, we suggest that the major metabolites of KHPC-002 and KHPC-006 were [trans-l-diamino-cyclohexane-bis-l,2(diphenylphosphinoethane)platinum] and [cis-diaminocyclohexane-bis-l.2(diphenylphosphinoethane)platinum], respectively.

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병렬처리를 이용한 효율적인 수량 연관규칙 (Efficient Quantitative Association Rules with Parallel Processing)

  • 이혜정;홍민;박두순
    • 한국멀티미디어학회논문지
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    • 제10권8호
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    • pp.945-957
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    • 2007
  • 수량 연관규칙은 대량의 데이터베이스에 존재하는 데이터 중 수량적 속성이 강한 데이터를 항목으로 만들어 이진 연관규칙에 적용한다. 만약 중요한 의미를 내포하는 수량 데이터의 정의역 범위가 넓을 경우 정의역을 최소지지도에 만족하는 적정 구간으로 분할하여 빈발구간 항목을 생성하는 작업이 필요하다. 이러한 빈발구간 항목은 어떻게 생성되었느냐에 따라 생성된 규칙의 신뢰도에 큰 영향을 미치게 된다. 따라서 본 논문에서는 빈발구간 항목을 효율적으로 생성하는 방법을 제시한다. 본 논문에서 제안하는 방법은 기존 방법들에 비해 의미가 있는 구간을 분실하지 않고 최소지지도에 근접하는 세밀한 빈발구간을 생성하기 때문에 데이터가 가진 특성의 손실을 최소화할 수 있는 효율적인 방법이다. 또한 병합이 불필요한 곳에서는 병합을 시도하지 않고 빈도가 높은 구간만을 취해 병합하므로 수량의 정의역이 넓을 경우 기존 방법에 비해 실행속도가 월등히 빠른 효율적인 방법이다. 그리고 인구센서스와 같은 실제로 사용되는 데이터를 이용하여 클루닉스 HPC 시스템에서 병렬처리 수행을 통하여 제안 방법이 우수함을 보였다.

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NoC 동기회로 설계를 위한 불안정상태 분석 (Analysis of Metastability for the Synchronizer of NoC)

  • ;김강철
    • 한국전자통신학회논문지
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    • 제9권12호
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    • pp.1345-1352
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    • 2014
  • 최근에 SoC 버스구조의 대안으로 NoC가 대두되고 있으며, NoC에서 다중클럭이 사용되어 클럭의 주파수는 같지만 clock skew 등으로 인한 위상차이가 발생하므로 데이터 전송 시에 클럭에 대한 동기회로가 사용되고 있다. 본 논문에서는 NoC 클럭의 위상차가 발생하는 경우 데이터의 손실이 발생할 수 있는 불안정상태 (metastability)를 정의하고 분석한다. 180nm CMOS 공정 파라미터를 사용하여 래치와 플립플롭을 설계하고, 1GHz 클럭을 사용하여 모의실험을 수행하였다. 모의실험 결과에서 출력에 로직 1과 0이 아닌 중간 값을 가지는 불안정상태를 래치와 플립플롭에서 확인하였다. 그리고 불안정상태 값이 상당히 긴 시간 동안 존재하여 온도, 공정변수, 전원 크기 등의 주변 환경에 의하여 출력 값이 변할 수 있어 입력값을 손실할 수 있다는 것을 확인하였으며, 이러한 결과는 NoC에서 위상차 동기회로 설계 시에 유용하게 사용될 수 있을 것이다.