AAL2를 이용한 패킷기반 중계망에서의 호 허락/이탈 제어 알고리즘

장석기,김훈,박광채 조선대학교 전자정보통신연구소 2001 電子情報通信硏究所論文誌 Vol.4 No.2

The tandem network composed of the existing circuits network and packets network will integrate into a single network after this. that is, the circuit-based services of PSTN/ NISDN will integrate into the packet-based tandem network by using the devices of Media Gateway etc. moreover, because it is possible to multiplex the connections assigned to each subscriber by using AAL2 switching function of ATM network, we can heighten the utilization efficiency of network. In this paper, we described the VoDSL using an ATM tandem network and the call admission/ departure control algorithm, and appeared the performance estimation for the numerical results of multiplexer with bit dropping.

콘크리트의 파괴에너지 결정을 위한 3점 휨시험과 compact compression 시험의 비교 연구

김광석,장정수 朝鮮大學校 建設技術硏究所 1998 建設技術硏究 Vol.18 No.2

This paper studied on compact compression test which can calculate fracture energy by the smallest specimen and three point bending test of the most stable system which have regular thickness and inital crack. This study supposed that width W_(c) of microcrack zone is propotioned to "n" thimes of maximun aggregate size, and that derived size effect expression is propotioned to "nd^(m)_(a)". This paper could derive following conclusion as studying and researching reference and data of this experimentation, and as deriving new size effect law through dimensional analysis and similitude law. New size effect expression derived from expression which consider maximum aggregate size on the basis of strength criterion and energy criterion through dimensional analysis and similitude law. The effect of maximum aggregate size to width of microcrack zone was proportioned to rater "nd^(m)_(a)" than "n" times of maximum aggregate size da through reference and experimentation of this paper. This paper shows that concrete fracture energy G_(f) supposed in new model is accord with fracture energy by BKP method, also shows that we can get the long-awaited fracture energy fully for by CCS because specimen by three-point bending test is well accord with theoretical size on fracture energy of specimen by compact compression specimen each other.

철근비, 세장비 및 강도에 따른 철근콘크리트 기둥의 좌굴거동에 관한 실험적 연구

김광석,장정수 조선대학교 국토개발연구소 1997 국토개발연구 Vol.17 No.1

As most of the study for columns have been carried out analytically by solving the governing differential equation of columns, the prediction of behavior of columns is almost impossible when the columns exist as a part of complex structure. To study experiment of the behavior of reinforced concrete columns with normal and high strength, the 80mm square cross section was used and the amount of eccentricity was 24mm. The compressive strengths of column specimens with slenderness ratios of 10, 60 and 100 were 260, and 879kgf/㎟. The longitudinal steel ratio of columns with bending about a section diagonal and about a principal axis were 1.98%(4-D6) and 3.95%(8-D6). The ratio of ultimate load capacity to that of short column with the same eccentricity was much decreased at high slenderness ratio with increasing the compressive strength of concrete. And the lateral displacement of slender column at the ultimate load was decreased as the strength was increased.

전분/펙틴/몬모릴로나이트 나노복합 필름의 특성 및 산소 투과도 연구

서석훈,서길수,유성구,신용섭,정세환,김성철,배광수,이태진,장상희,신부영 한국공업화학회 2003 공업화학 Vol.14 No.8

Na^(+)-MMT로부터 제조한 생분해성 전분/펙틴/몬모릴로나이트 나노복합재료의 기계적 특성, 열적 특성, 그리고 산소 투과성을 연구하였다. XRD와 TEM의 결과로부터 고분자의 삽입으로 인하여 실리케이트 층간 간격이 증가하였으며, 또한 삽입형 전분/펙틴/몬모릴로나이트 나노복합재료임을 확인하였다. 합성된 전분/펙틴/몬모릴로나이트 나노복합재료의 경우 적은 양의 MMT로부터 기계적 특성과 열적 안정성이 우수함을 보였다. 그리고 전분/펙틴/몬모릴로나이트 나노복합재료의 산소 투과성은 고분자 매트릭스에 분산되어 있는 몬모릴로나이트에 의하여 현저히 저하됨을 보여주었다. Mechanical property. thermal property. and oxygen permeability of biodegradable Pectin/Starch-montmorillonite nanocomposite, prepared with Na-MMT, have been studied X-ray diffraction and TEM experiments on polymer/silicate composite samples demonstrated that the intercalation of polymer chains leads to increase in the spacing between silicate layers. In addition, it were found that the intercalated Starch/Pectin/monotmorillonite nanocomposite were prepared. It was found that the addition of only a small amount of clay was enough to improve the thermal stability- and mechanical property of Starch/Pectin/montmorillonite nanocomposite. Oxygen permeability of Starch/Pectin/montmorillonite composite was generally lower than that of pectin/starch.

철근콘크리트 기둥의 좌굴파괴에 의한 철근비 및 큰크리트 압축강도의 실험적 연구

김광석,장정수,박진희 조선대학교 국토개발연구소 1997 국토개발연구 Vol.17 No.1

This study investigates the effect of compressive strength and longitudinal steel ratio of concrete on the behavior of reinforced concrete columns and conducts the experiment of the behavior of reinforced concrete columns with normal and high strength by giving a slenderness ratio(λ=50) the columns with square section (100×100 mm) to analyze the relations to bending moment, bending displacement and ultimate strength and by having the variables of concrete compression strength (180kgf/㎠, 819kgf/㎠) and longitudinal steel ratio (0.5%, 1%, 4%, 5.7%, 10.3%). As a result, the strain of compressed steel shows considerably increased trend more than tensile steel strain and on the form of fracture in the case of low strength, as the longitudinal steel ratio is increased more, the number of crack in considerably increased and on the form of fracture in the case of high strength, there in little crack in early loading, but when it reaches the ultimate loading, it causes instantaneous breaking. Especially, when column of 0.5% and 1% of longitudinal steel ratio reaches its ultimate loading, it is broken with the phenomena that the both sides of central part are divided, and the cases of 5.7% and 10.3% of longitudinal steel ratio, the ultimate loading value is not greatly increased.

내시경적 점막절제술로 치험한 식도 과립상 세포종 1례

강혁주,김성욱,최석진,이중현,장재식,서영범,윤병구,박건욱,김성자,김용섭,강승완,이구,양창헌,이창우,김욱년,이광헌,서정일 동국대학교 의학연구소 2000 東國醫學 Vol.7 No.-

과립상 세포종은 Schwann 세포 기원으로 생각되며 인체에 비교적 드물게 발생한다. 과립상 세포종은 전신 어느 곳에서나 발견될 수 있으나 주로 혀, 구강, 피부 혹은 유방 등에서 호발하며 드물게 위장관에서 발견된다. 위장관에서는 식도에서 가장 호발하며 다음으로 위, 대장 순이다. 과립상 세포종은 대부분, 특히 위장관에서는 양성이며 소수의 악성 병변이 보고되었다. 이러한 이유와 함께 수술 전의 진단이 어렵기 때문에 과립상 세포종에 대한 근본적인 치료는 현재까지 외과적 절제술이다. 최근에 시도되는 치료방법들로는 내시경적 레이저 치료, 용종절제술, 내시경적 점막 절제술 등이 있다. 저자들은 상부 소화관 내시경검사를 시행하여 식도 과립상 세포종을 진단하고 내시경적 점막 절제술을 시행하여 합병증 없이 퇴원하여 현재 재발없이 경과 관찰중인 1례를 경험하였기에 보고하는 바이다. Granular cell tumors, which occur infrequently, are probably of Schwann cell origin. They can occur almost anywhere in the body but usually affect the tongue, oral cavity, skin, or breasts and are rarely found in the gastrointestinal tracts. The esophagus is the most frequent gastrointestinal site, followed by the stomach and the colon. Granular cell tumors are generally benign, especially in the gastrointestinal tract, some malignant lesions have been reported. For this reason, and also because preoperative diagnosis is difficult, the standard treatment for granular cell tumor has until now been surgical excision. In recent years, other therapeutic methods is endoscopic laser therapy (ELT), polypectiomy, endoscopic mucosal resection (EMR). We report a case of esophageal granular cell tumor which was diagnosed by an endoscopy and managed using an endoscopic mucosal resection without complication.

돼지에서 정맥, 근육 그리고 경구 투여시의 enrofloxacin의 약물동태학

윤효인,김무열,박승춘,조준형,박병권,이내경,노상석,장범수,신광순,조명행 충남대학교 수의과대학 동물의과학연구소 1996 動物醫科學硏究誌 Vol.4 No.-

In order to characterize pharmacokinetic profiles according to route of a new enrofloxacin salt form (Enrotil®), it was given to 4 healthy pigs via oral (p.o.), intramuscular (i.m.) or intravenous (i.v.) administrations at a dose rate of 5 ㎎/㎏ body weight. Enrofloxacin (ENFX) in serum was detected by bioassay using E. coli BE1186 as a test organism. The biological elimination half-lives (t_1/2(β)) of ENFX were 6.76±0.99 h (i.v.), 7.16±2.30 h (i.m.) and 11.45±3.90 h (p.o.), Volume of distribution (Vd) of enrofloxacin was 2.20±0.31 L/㎏ (i.v.), 2.52±0.60 L/㎏ (i.m.) and 1.88±0.33 L/㎏ (i.m.). Mean residence time (MRT) was 8.77±1.26 h after i.v. injection and the maximal concentration time (Tmax) following p.o. and i.m. administration was 0.76±0.09 h and 0.60±0.12 h, indicating a rapid absorption from these routes. Bioavailibility (F) was calculated as 64.1% for p.o. administration and 59.71% for i.m. injections. In summary, the newly formulated enrofloxacin salt form has shown a high water solubility, rapid absorption and large tissue distribution, suggesting a potential antibacterials for oral application on a large scale in veterinary sectors.

Carbon Nanotube/Polymer Thermoelectric Papers and Fibers

Kwang-Suk Jang(장광석) 한국고분자학회 2019 한국고분자학회 학술대회 연구논문 초록집 Vol.44 No.2

Temperature-size rule is modulated by macronutrient balance in a caterpillar

Kwang Pum Lee,Taehwan Jang,Myung Suk Rho 한국응용곤충학회 2016 한국응용곤충학회 학술대회논문집 Vol.2016 No.04

Most ectotherms mature at a larger body size in colder conditions. This negative relationship between developmental temperature and final body size is termed the temperature-size rule. In this study, we investigated how dietary protein:carbohydrate (P:C) balance modulates the fundamental relationship between temperature and body size in the final-instar caterpillars of Spodoptera litura. The magnitude and sign of the thermal reaction norm for body size were altered by the dietary P:C balance of the food eaten by caterpillars. The slope of the reaction norm was flat for caterpillars raised on a nutritionally balanced food (P:C = 1:1) but was negative for those on imbalanced foods (1:5 or 5:1). When allowed to self-compose their preferred diet, caterpillars preferred carbohydrate-rich food at higher temperatures. The negative impact of high temperature on body size was mitigated by such a temperature-driven shift in nutrient preference. This study highlights the importance of macronutrient balance as a key factor modulating the relationship between temperature and body size in insects.

Modified Mesoporous Silica Gas Separation Membranes on Polymeric Hollow Fibers

Jang, Kwang-Suk,Kim, Hyung-Ju,Johnson, J. R.,Kim, Wun-gwi,Koros, William J.,Jones, Christopher W.,Nair, Sankar American Chemical Society 2011 Chemistry of materials Vol.23 No.12

<P>Thin, continuous, mesoporous silica membranes are formed on polymeric hollow fibers via liquid-phase coating at roomtemperature and aging with tetraethylorthosilicate (TEOS) vapor at 100 °C. After liquid extraction of the surfactant template and mesopore infiltration with an aminoalkyloctasilsesquioxane, the membrane displays CO<SUB>2</SUB>-selective gas permeation properties.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2011/cmatex.2011.23.issue-12/cm200939d/production/images/medium/cm-2011-00939d_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm200939d'>ACS Electronic Supporting Info</A></P>