• 한국환경복원기술학회지
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• 제9권1호
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• pp.89-99
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• 2006

The growth and biomass of reeds(Phragmites australis) growing in a subsurface treatment wetland system were investigated from April 2003 to October 2003. Nitrogen(N) and phosphorous(P) concentrations in above-ground(AG) and below-ground(BG) tissues of reeds were examined and the removal rate of N and P by reeds were analyzed. The system, 29 m in length, 9 m in width and 0.65 m in depth, was constructed in June 2001 on a floodplain in the down reach of the Kwangju Stream in Korea in order to purify polluted water of the stream. A bottom layer of 45 cm in depth was filled with crushed granites(15~30 mm in diameter) and a middle layer of 10 cm in depth was filled with pea pebbles(10 mm in diameter). An upper layer of 5 cm contained course sand. Reeds were transplanted on the surface of the system, which were dug out of natural wetlands, and their shoots were trimmed 40 cm in height. The height and density of the shoots averaged 237.7 cm and 244.0 shoot/$m^2$, respectively, when the reeds grew fully. The maximum biomass of AG and BG tissues were 1,964 and 1,577 g/$m^2$, respectively, and the AG : BG ratio of biomass was 1.26. Mean AG and BG dry weights were recorded as 1,355 and 748 g/$m^2$, respectively. The AG and BG tissue concentrations of N averaged 12.37 and 10.01 mg/g, respectively, and those of P 2.37 and 2.03 mg/g, respectively. Inflow to the system averaged 40 $m^3$/day. The concentrations of total nitrogen(T-N) in influent and effluent were 8.4 mg/L and 3.2 mg/L, respectively, and those of total phosphorous(T-P) were 0.73 and 0.38 mg/L, respectively. The total removal of T-N and T-P by the system during the investigation period averaged 140.2 and 9.7 g/$m^2$, respectively, and the total uptake of N and P by the reeds were calculated as 24.39 and 4.73 g/$m^2$, respectively. Average removals of about 17% of N and about 49% of P by reeds were recorded. The N and P concentrations in AG tissues were significantly different among the three zones of the system:near to inflow(St1), in the middle of system(St2), and near to outflow(St3). The N and P concentrations in BG tissues were also significantly different among St1, St2 and St3. N and P concentrations in AG and BG tissues of reeds growing in St1 were higher than those in St2 and St3. The height and density of shoots of reeds in St1 were larger than those in St2 and St3. Significant amounts of N and P in the influent were taken up by reeds in St1.

• 대한산업공학회지
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• 제32권4호
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• pp.369-372
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• 2006

Suppose that a customer arrives at the GI/M/1/K queueing system when there are customers in the system, $n,m{\geq}0,\;n+m{\leq}K$. Sooner or later, the number of customers in the system will reach . In this paper, we present the Laplace transform of the remaining interarrival time upon reaching level, for the first time, since a customer arrived when there are customers in the system.

• 한국발생생물학회지:발생과생식
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• 제18권2호
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• pp.99-106
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• 2014

Fish larvae are immediately exposed to microbes from hatching to maturation of their lymphoid organs, therefore effective innate mechanisms is very important for survival. However, the knowledge of the development of immune system in fish is limited and in demand now. In vertebrates, recombination-activating gene 1 (RAG-1) and immunoglobulin M (IgM) have been considered as very useful markers of the physiological maturity of the immune system. In this study, the expression of the both genes was assessed throughout the early developmental stages of olive flounder larvae (5-55 dph) and used as markers to follow the development of immune system. RAG-1 and IgM mRNA expression was detectable at 5 dph and remained so until 55 dph. These patterns of expression may suggest that the olive flounder start to develop its function around 5 dph. Tissue distribution was found that both genes mRNAs are only expressed in the immune-related organ such as spleen, kidney and gill. The early detection of IgM mRNA led to the investigation of its presence in oocytes. Both RAG-1 and IgM mRNA transcripts were detected in unfertilized oocytes, suggesting that they are maternally transferred. The biological significance of such a phenomenon remains to be investigated.

• Journal of the Korean Statistical Society
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• 제30권4호
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• pp.661-666
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• 2001

In this paper we consider an M/G/1 queue where the server of the system has a vacation time and the service policy is limited-1. In this system, upon termination of a vacation the server returns to the queue and serves at most one message in the queue before taking another vacation. We consider two models. In the first, if the sever finds the queue empty at the end of a cacation, then the sever immediately takes another vacation. In the second model, if no message have arrived during a vacation, the sever waits for the first arrival to serve. The analysis of this system is particularly useful for a priority class polling system. We derive Laplace-Stieltjes transforms of the waiting time for both models, and compare their mean waiting times.

• 전기화학회지
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• 제3권4호
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• pp.241-245
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• 2000

비정질 $MnO_2\;nH_2O$ 전극재료를 사용한 pseudo-capacitor를 설계 제작하여 특성을 평가하였다. 100mV/s의 cyclic voltammogram으로부터 측정한 결과, 이 전극재료의 안정한 potential window는 1V이고 비용량은 250F/g이었다. TDMA(Time Division Multiplex Algorithm) pulse 시험에서 TDMA 시스템 (2 parallel-pseudo-capacitor systems) 은 0.22V의 ohmic voltage drop과 0.38V의 capacitor voltage drop을 보여주었다. 이 TDMA system의 total voltage drop이 0.60V이므로 TDMA 위성통신 휴대전화의 요건인 1V maximum voltage drop을 충족하였다. 또한, 이 system의 ESR과 비용량은 각각 $55m{\Omega}$과 105mF이었다. 따라서 이 TDMA system이 위성통신 휴대전화를 위한 load-leveling 캐패시터로 응용 가능함을 확인하였다.

• 한국통신학회논문지
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• 제12권4호
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• pp.347-356
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• 1987

本 論文에서는 高速 光 디지털 傳送시스템과 같은 高速 unipolar 信號 傳送시스템에 適合한 새로운 mBIZ 傳送路符號를 提案하였다. mBIZ符號는 情報信號系列 傳送速度를 $\frac{(m+1)}{m}$ 만큼 速度變換한 後 m 비트마다 補助 서어비스 비트 하나를 揷入한 信號系列과 出力傳送路符號系列의 한 비트를 遲延시킨 信號系列을 Exclusive NOR하여 符號化하기 때문에 redundancy를 줄일 수 있을 뿐만 아니라 復號回路 역시 간단하게 構成할 수 있다. mBIZ符號는 回符號連積數를 (m+1)비트 이내로 抑壓할 수 있으며 傳送路符號系列의 마크率이 1/2이기 때문에 電力 스펙트럼에 存在하는 高低周波 成分들을 抑壓할 수 있다.

• 식물조직배양학회지
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• 제21권4호
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• pp.201-206
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• 1994

Glycine, valine, alanine과 histidine의 수송은 모든 실험된 중성 아미노산에 의해 경쟁적인 방해를 당하였다.그리고 reciprocal 연구 결과로 이들 중성 아미노산들은 서로 carrier reciprocal의 활성부위를 점유하기위해 경쟁하므로 같은 운반자를 소유한다. Histidine은 전하를 띄우지 않은 상태로 중성 아미노산 운반자를 통해서 능동수송된다. 중성 운반자의 $K_m$ 값은 아미노산이 운반자에 대한 친화성에 따라서 3가지로 분류하였다. 0.1 mM 보다 작은 값, 0.1 mM에서 0.5 mM 사이에 있는 값고 0.5 mM 보다 큰 값이다. $V_{max}\;는\;3.12mol{\cdot}h^{-1}{\cdot}g{\;}fresh{\;}weight^{-1}\;과\;15.1\;{\mu}mole{\cdot}h^{-1}{\cdot}g{\;}fresh{\;}weight^{-1}$ 사이에 있다. 중성 아미노산은 아미노산 한개당 수소이온 한개가 동반수송되고, $K^{+}$ 한개가 전하보상을 위해서 배출된다. Histidine 분자도 1 분자당 1개의 수소이온과 동반수송되나 전하를 띄운 histidine 분자로부터 수소이온 한개가 배지로 떨어져 나오므로 동반수송된 수소이온의 움직임을 일시적으로 측정 할 수 없다.

• 한국항공운항학회지
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• 제11권1호
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• pp.41-55
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• 2003

A calibration jet system using separate blower is developed to calibrate a flow sensor effectively. Designed open circuit type mini calibration jet system, which has the dimension of $0.5m(W){\times}1.17m(H)$ is small compared with conventional calibration jet systems. The exit of nozzle has exchangeable contractions with a cross section area of $38.5cm^2$ , and a cross section area of $113.1cm^2$, respectively. The ranges of wind speed at exit of exchangeable nozzles are $7.5{\sim}42\;m/s$ and $1.8{\sim}16.5\;m/s$, respectively. The input power for the high pressure blower is 1.18kW. The turning vanes for corner was rolled flat plate parallel to the flow direction. The flow conditioning screen was located immediately downstream of the wide-angle diffuser. The honeycomb and two flow conditioning screens were located in the stagnation chamber. From the economical point of view and the simplicity of the calibration jet system set up and handling, it can be said that the developed calibration jet system is an effective calibration jet system. This system can also be used to calibrate the flow sensor with high resolution.

• International Journal of Reliability and Applications
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• 제3권4호
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• pp.165-171
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• 2002

An optimization of the M/M/1 queue with impatient customers is studied. The impatient customer does not enter the system if his or her virtual waiting time exceeds the threshold K ＞ 0. After assigning three costs to the system, a cost proportional to the virtual waiting time, a penalty to each impatient customer, and also a penalty to each unit of the idle period of the server, we show that there exists a threshold K which minimizes the long-run average cost per unit time.

• 대한산업공학회지
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• 제6권1호
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• pp.1-7
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• 1980

An exact solution technique for M/M/s multi-server demanding queue is introduced, and a general form of the curves representing service rates of the system is presented. As the number of customers in the system increases, the service rate is shown to increase initially, then decrease, and finally converge to a certain value. It is also shown that this phenomenon persists regardless of the numbers of servers and customer types.