• Korean Chemical Engineering Research
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• 제48권2호
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• pp.244-252
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• 2010

본 연구에서는 Triple-bed 흡착튜브를 제작하여 열탈착장치와 GC-MS로써 다성분 복합 악취성물질 및 휘발성유기 화합물을 동시분석 가능성을 평가하고자 하였다. Triple-bed 흡착튜브는 하나의 튜브에 Tenax-TA와 소량의 Carbopack B 및 Carbosieve SIII 흡착제를 흡착강도 순으로 3단 배열된 것이다. GC-MS의 분석조건은 mass range 20~350 m/z, 불순물 1 ppm 이하의 헬륨을 운반가스로 하여 저비점 저분자량 물질의 분리동정에 효과적일 수 있도록 하고, 목적이온 추출을 통하여 정량하였다. 그 결과 ppbv 수준의 $C_1{\sim}C_5$의 알콜(4), 알데히드(6), 케톤(2) 그리고 황화합물(2)을 포함한 14종의 물질 모두 99%이상의 회수율과 양호한 재현성 및 직진성으로 동시분석이 가능하였다. 비교적 휘발성이 강하고 분자량이 낮은 물질인 메틸알콜, 아세트알데히드는 상대습도 45% 이하, 흡착유속 50 mL/min, 흡착량 2 L 이하에서 높은 회수율로 보다 안정적으로 정량분석이 가능하였다. 또한 목적이온 추출은 물질피크가 겹쳐 나타난 경우에도 다성분 물질을 각각 정량 가능하였다.

• 한국세라믹학회지
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• 제20권2호
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• pp.166-172
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• 1983

In this study the sillicon-alloyed isotropic pyrolytic carbon was deposited in the tumbling bed from the pyrolysis of propane and silicon tetrachloride and investigated whether the silicon-alloyed isotropic pyrolytic carbon deposited in this study was usable as bionaterial or not. The silicon-allyed isotropic pyrolytic carbon was varied by controlling the process variables such as propane con-concentration and the argon flow rate flowing in to the silicon tetrachloride bubbler at a fixed reaction bed tempera-ture of 120$0^{\circ}C$ a rotation of reaction tube of 40 rpm a bed particle weight of 7.5 g and a total flow rate of 21/min; the propane concentration was varied from 10 to 70 and the argon flow rate flowing into the silicon tetrachloride bubble from 0 to 1000 cc/min. The results show that the silicon-alloyed isotropic pyrolytic carbon was obtained at all conditions investigated, . And then the alloyed silicon content is rangion from 7 to 14.5 wt%. The density and deposition rate of deposited silicon-alloyed isotropic carbon increased axxording to silicon content and propane concentration. And the apparent crystal-size(Lc) of pyrolytic carbon is not changed with silicon content. The density and apparant crystallite size are respec-tively in the range of 1.94 to 2.06 and 20 to 25$\AA$ It is shown that the silicon-alloyed isotropic pyrolytic carbon ob-tained in this experiment is usable as biomaterial.

• 대한토목학회논문집
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• 제13권4호
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• pp.123-129
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• 1993

기연구 발표된 수많은 세굴 예측공식들은 여수로나 관암거 하류의 침강지내에서 발생하는 실제 세굴 깊이나 세굴 방지에 필요한 최소 침강지수심을 예측하기가 불가능할 정도로 광범위한 예측치를 나타내고 있다. 이같은 광범위한 예측 세굴 깊이는 대부분 세굴 지배인자에 대한 심도깊은 연구의 부족에 따른 인자들의 지나친 단순화에 기인하고 있다는 것을 문헌조사를 통하여 알수 있었다. 따라서 본 연구는 실험을 통하여 세굴을 지배하는 주요 지배인자들의 영향을 검토하였다. 문헌조사로부터 찾을 수 있었던 세굴 지배인자는 침강지수심, ?의 크기와 폭기정도, 하상입자의 입도분포 및 노출도 등이었으며 본 연구에서는 ?의 수리학적 특성 및 침강지 수면에서의 입사각, 침강지의 기하학적 특성, 그리고 ?의 크기 및 하상입자 크기의 영향을 중점적으로 검토하였다. 그 결과 침강지 수심과 ?의 수리학적 특성 및 기하하적 특성, 그리고 하상입자의 크기 등이 세굴을 지배하는 주요인자임을 알 수 있었다. 특히 기존 실험연구들의 광범위한 세굴 예측치는 ?의 크기와 하상입자의 크기에 대한 기하학적 상사법칙을 무시함에 기인하였음을 발견하였다.

• 공업화학
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• 제16권5호
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• pp.603-608
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• 2005

본 연구는 zinc titanate를 탈황제로 사용하는 유동층 탈황공정에서 고체 입자 마모특성을 고찰하는 것을 목표로 내경 0.035 m, 높이 1.34 m의 기체유동층 실험장치에서 수행되었다. 다공판 분배기에서 고속 분사 제트와 유동층 내부의 기포요동이 입자마모의 주요 원인으로 사료되었다. 탈황제의 마모속도가 작아서 회분식 측정결과가 연속식 유동층에 근사하게 적용될 수 있는 조건에서 수행되었다. 탈황공정에서 주요 변수인 기체유속, 온도, 압력, 층물질량의 변화에 따른 AI(attrition index)와 CAI(corrected attrition index)를 측정하였다. AI(5), CAI(5)는 층 무게가 증가함에 따라 감소하였다. 입자는 일정기간 충격에 의한 피로현상이 있은 후 마모되는 것으로 판단되었다. AI와 CAI는 기체속도, 상대습도, 압력이 증가함에 따라, 온도가 감소함에 따라 증가하였다. 입자마모는 주로 제트에 의하여 일어났으며 절단(fragmentation)보다 마쇄(abrasion)에 의하여 더 많은 미분입자가 발생하였다.

• 상하수도학회지
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• 제22권1호
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• pp.31-38
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• 2008

The primary objective of this study was to evaluate the variation of the molecular size distribution by granular activated carbon (GAC) adsorption. GAC adsorption was assessed by using the rapid small-scale column test (RSSCT) and high-performance size-exclusion chromatography (HPSEC) was used to analyze the molecular size distribution (MSD) in the effluent of GAC column. RSSCT study suggested that GAC adsorption exhibited excellent interrelationship between dissolved organic carbon (DOC) breakthrough and MSD as function of bed volumes passed. After GAC treatment, the nonadsorbable fraction which was about 25percents of influent DOC corresponded to the hydrophilic (HPI) natural organic carbon (NOM) of NOM fractions and was composed entirely of <300 molecular weight (MW) in the HPSEC at the initial stage of the RSSCT operation. The dominant MW fraction in the source water was 1,000~5,000daltons. At the bed volumes 2,500, MW <500 of GAC treated water was risen rather than it of source water. After the bed volumes 7,300 of operation, the MW 1,000~3,000 fraction was closed to about 80percents of DOC found in the GAC influent. The Number-average molecular weight (Mn) value determined using HPSEC for the effluent of GAC column was gently increased as DOC breakthrough progress. The quotient p(Mw/Mn) can be used to estimate the degree of polydispersity was shown greatest value for the GAC effluent at the initial stage of the RSSCT operation.

• 수산해양교육연구
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• 제18권3호
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• pp.236-243
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• 2006

A series of surveys are performed to evaluate the abundance, composition and distribution of marine debris on the sea bed around the Busan port. In order to set up a master plan for the marine environmental pollution the relevant maritime authority must understand how many and w㏊t kinds of marine litters are distributed on the sea bed. At first we planed to survey areas divided regularly according to the coast line but there were many sea going vessels and fishing boats. So we selected and surveyed the around area where there were no sea going vessels or fishing boats.The obtained results are as follows: 1. The mean values of litters in number and weight are 5.8 pieces/㏊. and 3.5㎏/㏊. respectively. 2. The highest density in terms of number are vinyl and plastic item, and in weight are fishing gear and ship articles. 3. The nearer to the shore we surveyed the more we collected in terms of the density of marine litters in number and in weight per hectare. 4. Eel pot, oiled waste, rope, others, other pot and net of fishing gear litters in number were 59.9, 22.7, 7.9, 4.5, 3.1 and 1.9% respectively. 5. There is no relationship between the amount of fish caught and the amount of marine debris.

• Journal of Plant Biology
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• 제13권4호
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• pp.13-22
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• 1970

The rice variety, Kwanok, was reared in the water, land and salt seed beds and transplanted to the reclaimed soil area having an average of 0.48% salt content (0.67% at the end of April). The plant height of land bel seedlings at transplanting stage was short but the dry-weight/plant-height ratio was large and the rooting ability was vigorous remarkably after transplantation in the salty area. The central cylinder, vessels, sclerenchyma, endodermis and other mechanical tissues of the root of land bed seedlings were well developed while the size of cortical cell layers were small. The cytoplasm of the cortical parenchyma at the root tips seemed to be most abundant in the land bed seedlings. The formation of the aerial cavity in the cortex of primary root was rapid and it seemed that the developmental mechanism of the aerial cavity in the rice plant roots was related to the development of the lateral roots.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.165-172
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• 2004

Co-incineration of coal and wastewater sludge was r;erfonn:rl in a O.lMWth bench scale circulating fluidized bed combustor(CFBC) Sludge was received from a wastewater treatment plant in a dye industrial complex in Busan. Metropolis. Moisture content of received sludge was 80%. Coal and sludge mixture was prepared with weight ratio of 90/10, 85/15 and 80/20. Co-combustion characteristics of the coal and sludge mixture demonstrated stable combustion conditions. Component analysis, incineration characteristics, boiler performance was measured before and after the test and application for commercial 59MWth CFBC boiler. The release of hazardous components such as $SO_2$ and Cl was suppressed by the presence of inherent minerals of Ca, Na, K in coal and sludge mixture. Pre-drying was not essential but it was recommended for the benefits of manageability of sludge.

• 한국작물학회지
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• 제60권4호
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• pp.412-420
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• 2015

Even though phosphorus (P) is essential element for plant growth and development, it is not enough for crop production in soil. To breed more P deficient tolerance rice, screening and selection in rice population is needed. We tried to develop more simple and rough screening method for breeding of P deficient tolerance rice. In P deficient condition, tiller number was dramatically decreased among yield components in rice. Though this result, we confirmed tiller number could be the best marker in screening of P deficient tolerance rice. 480 rice genetic resources were cultivated in rice bed tray filled with P deficient soil for four weeks and each dry weight was measured. Among them, the 55 kinds of genetic resource were selected then cultivated in paddy field with 3 fertilizer conditions. Plant dry weight and tiller number in ripening stage were shown significant difference according to P condition. Plant dry weight and tiller number in ripening stage was highly correlated especially in P deficient condition. Furthermore, the tiller number in ripening stage and plant dry weight in rough screening were shown high degree correlation. Though these results, we might expect measuring of plant dry weight after cultivation in rice bed tray filled with P deficient soil could be a simple and effective screening method in selection of P deficient tolerance rice.

• Journal of Biosystems Engineering
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• 제37권3호
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• pp.155-165
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• 2012

This study was performed to offer the data for design of the seedling bed transfer equipment to make the automation of working process in a plant factory. The seedling bed transfer equipment pushing the seedling bed with bearing wheels on the rail for interconnecting each working process by a pneumatic cylinder was made and examined. The examined transfer force to push the seedling bed with a weight of 178.9 N by the pneumatic cylinder with length of 60 cm and section area of 5 $cm^2$ was measured by experiments. The examined transfer forces was compared with theoretical ones calculated by the theoretical formula derived from dynamic system analysis according to the number of the seedling bed and pushing speed of the pneumatic cylinder head at no load. The transfer function of the equipment with the input variable as the pushing speed $V_{h0}$(m/s) and the output variable as the transfer force f(t)(N) was represented as $F(s)=(V_{h0}/k)(s+B/M)/(s(s^2+Bs/M+1/(kM))$ where M(kg), k(m/N) and B(Ns/m) are the mass of the bed, the compression coefficient of the pneumatic cylinder and the dynamic friction coefficient between the seedling bed and the rail, respectively. The examined transfer force curves and the theoretical ones were represented similar wave forms as to use the theoretical formular to design the device for the seedling bed transfer. The condition of no vibration of the transfer force curve was $kB^2>4M$. The condition of transferring the bed by the repeatable impact and vibration force according to difference of transfer distance of the pneumatic cylinder head from that of the bed was as $Ce^{-\frac{3{\pi}D}{2\omega}}<-1$, where ${\omega}=\sqrt{\frac{1}{kM}-\frac{B^2}{4M^2}}$, $C=\{\frac{\frac{B}{2M}-\frac{1}{kB}}{\omega}\}$, $D=\frac{B}{2M}$. The examined mean peak transfer force represented 4 times of the stead state transfer force. Therefore it seemed that the transfer force of the pneumatic cylinder required for design of the push device was 4Bv where v is the pushing speed.