• 한국가구학회지
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• 제20권3호
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• pp.247-252
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• 2009

The objective of this study was the dimensional stabilization of Korean red pine (Pinus densiflora) wood by the water-based thermosetting resin. A commercial melamine-formaldehyde resin was impregnated into wood samples and cured. The weight and dimensional change of woods treated by the resin, and the absorption and dimensional behavior of treated woods were investigated. The melamine-formaldehyde resin treatment improved significantly the dimensional stability of pine wood and showed about 40% of antiswelling efficiency. The mechanism of dimensional stabilization was interpreted as the complicated reason, such as bulking effect by the resin in cell wall, mechanical restraint and/or blocking of hygroscopic site by the resin in lumen.

• 대한약리학회지
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• 제12권2호
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• pp.7-11
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• 1976

A portion of duodenum laid pancreatic duct opening were perfused continuously with physiological saline under urethane anesthesia in rats. The pancreatic amylase secretory response to caerulein was studied with autonomic blockers, such as phenoxybenzamine, dibenamine, phentolamine, hexamethonium, propranolol, atropine, and cyproheptadine. The pancreatic amylase output to caerulein, 7.5ng/kg i.v., was markedly increased and the value was approximately three times greater than control. The caerulein-stimulated pancreatic amylase secretion was significantly decreased by i.v. phenoxybenzamine and propranolol treatment, but not by phentolamine or dibenamine. Secretory response of pancreatic amylase to caerulein was not affected by i.v. atropine, hexamethonium or cyproheptadine. These result lead to the conclusion that phenoxybenzamine may inherently inhibit the secretory response of pancreatic amylase to caerulein, and this effect was not related with ${\alpha}-adrenergic$ receptor blocking action.

• The Korean Journal of Physiology and Pharmacology
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• 제5권2호
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• pp.183-188
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• 2001

To elucidate antidiabetic effect and mechanism(s) of acarbose in a polygenic spontaneous hyperglycemic and hyperinsulinemic diabetic animal model, $KKA^y$ mice, acarbose was administered orally for 4 weeks and effects on body weight, plasma glucose and insulin levels, genetic expressions of intestinal sucrase-isomaltase (SI), sodium-glucose cotransporter (sGLT1) and glucose transporter in quadriceps muscle (GLUT4) were examined in this study. Although no differences in body weight were detected between control and acarbose-treated groups, plasma glucose level in acarbose-treated group was markedly reduced as compared to the control. In the mechanism study, acarbose downregulated the SI and SGLT1 gene expressions, and upregulated the GLUT4 mRNA and protein expressions when compared to the control group. In conclusion, the data obtained strongly implicate that acarbose can prevent the hyperglycemia in $KKA^y$ mice possibly through blocking intestinal glucose absorption by downregulations of SI and sGLT1 mRNA expressions, and upregulation of skeletal muscle GLUT4 mRNA and protein expressions.

• 한국통신학회논문지
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• 제22권2호
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• pp.268-279
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• 1997

In this paper, we show the movable boundary (MB) method is the effective bandwidth allocation strategy for the ABR service among existing bandwidth allocation methods. The MB method can gurantee the QOS requirement according to the service priority and improve bandwidth utilization using the characteristics of the ABR service. The threshold values of the MB, which have an important effect upon connection blocking probability(CBP) performance of each service, are obtained by simulation. The MB method with the fixed thresholds, however, may not have good performance to variation of input traffic parameters. We suggest the dynamic MB method which changes the threshold values adaptively according to the required bandwidth of input traffic. We also show that the dynamic MB method can urantee the CBP performance according to the service priority regardless of variation of input traffic parameters.

• 한국정보처리학회논문지
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• 제5권1호
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• pp.33-39
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• 1998

본 논문에서는 고속병렬컴퓨터와 같이 다중노드로 구성된 시스템에서 사용되는 유한 버퍼를 가지는 노드간 통신시스템의 성능을 대기행렬모형을 사용하여 평가/분석하였다. 전체 시스템을 각 서브 시스템별로 나누어 버퍼크기의 제한으로 발생하는 블로킹을 고려한 안정상태에서의 도착률과 확률 값들을 구한 뒤, 이를 이용하여 전체 시스템의 성능을 분석하는 방법을 사용하였다. 평균 전송시간과 처리율을 구하여 이를 시뮬레이션 결과와 비교 검증하였으며, 제안한 모형을 사용하여 버퍼의 크기가 처리율에 미치는 결과를 분석하였다.

• 약학회지
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• 제28권5호
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• pp.257-263
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• 1984

In our former report we observed that cinnarizine influenced the antihypertensive effect of propranolol beneficially, but not of metoprolol in SHR and normal cat. Cardiac contractilities and smooth muscle relaxations induced by above drugs were measured to elucidate their mechanism of action. In cinnarizine and propranolol treated group, both of negative inotropic and ${\beta}-blocking$ activity of propranolol in perfused rat hearts were increased and propranolol induced contraction in isolated arterial and trachea smooth muscle of the guinea pig was antagonized comparing to propranolol alone treated group. However, in the cinnarizine and metoprolol treated group, no significant differences in activity on the above were observed compared to metoprolol alone treated group.

• 한국세라믹학회지
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• 제36권9호
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• pp.923-929
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• 1999

The cause of optical nonlinearity induced in thermally poled silica glass is believed to be the space charge polarization. Since the second order optical nonlinearity (electro-optic effect) can be used in optical switches the optical nonlinearity in silica glass has drawn a large attention. Space charge polarization occurs when an ionic conducting material is subjected to dc electric field by the blocking electrode. Thermal poling performed to induce the optical nonlinearity in silica glass is basically identical to the process generating space charge polarization. As a first step to understand the mechanism of space charge polarization in silica glass hence the induced optical nonlinearity the absorption currents as functions of time were measured for various types of silica glasses and analyzed by the theory of space charge polarization. It was found that the electrical relaxation exhibited a step by the space charge polarization in the relatively long time range and dielectric loss peak showed a maximum at a specific temperature which is depending on type of silica glass. It was turned out that this relaxation might be a cause of nonlinearity in electrical conductivity of silica glass.

• 한국전기전자재료학회논문지
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• 제23권3호
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• pp.183-189
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• 2010

In this paper, the trench gate emitter switched thyristor(EST) withl trench gate electrode is proposed for improving snap-back effect which leads to a lot of problems in device applications. The parasitic thyristor which is inherent in the conventional EST is completely eliminated in this structure, allowing higher maximum controllable current densities for ESTs. The dual trench gate allows homogenous current distribution in the EST and preserves the unique feature of the gate controlled current saturation of the thyristor current. The characteristics of the 1700 V forward blocking EST obtained from two-dimensional numerical simulations (MEDICI) is described and compared with that of a conventional EST. we carried out layout, design and process of EST devices.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.126-129
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• 1999

In this paper, it is assumed that a mobile radio channel is a Rayleigh distributed multipath fading channel and Erlang capacity and equivalent channel numbers are calculated for the reverse link of a imperfect power controlled DS/CDMA cellular system considering both shadowing and multipath fading. The DS/CDMA blocking probability is calculated based on a new analysis method that considers Erlang capacity and ICF(interference correction factor) using the median value of $E_{b(i)}$/ $I_{o}$ corresponding to each reverse link user. It is showed that the effect of multipath fading must not be ignored in Erlang capacity of the IS-95 DS/CDMA cellular system and the Erlang capacity is decreased according to the increase of the deviation of the imperfect power control, to the decrease of the processing gain, to the increase of the voice activity.y.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.597-600
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• 1999

TMN5 used to test the performance of H.263 is a DCT-based H.263 which DCT is used as transform coding, but DWT is used instead of DCT and adaptive quantizer of being appropriate to DWT is designed in this paper while the structure of TMN5 is maintained. DWT-based H.263, which is proposed in this paper, is excellent in transplantation of the existing system and can improve frame rate by transmitting more Frame. Also, the average PSNR, objective quality of image, has been lost at degree of average 0.35㏈ in luminance signals, but has been improved over a average of 2㏈ in chrominance signals. Subjective quality of image has been improved as blocking effect, which has seriously occurred in DCT based H.263, is diminished. DWT-based H.263 can. therefore. advance video quality of image comparing with the existing ways.