• 한국소음진동공학회논문집
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• 제14권12호
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• pp.1347-1353
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• 2004

With respect to the researches of the optical flying head(OFH) , the head-gimbal assembly should be analyzed to guarantee the stable fabrication and the characteristics of shock resistance. The suitable design is proved through the Probabilistic analysis of the design parameters and material properties of the model. Probabilistic analysis is a technique that be used to assess the effect of uncertain input parameters and assumptions on your analysis model. Using a probabilistic analysis you can find out how much the results of a finite elements analysis are affected by uncertainties in the model. Another factor is analysis of the dynamic shock analysis. For the mobile application, one of the important requirements is durability under severe environmental condition, especially, resistance to mechanical shock. An important challenge in the disk recording is to improve disk drive robustness in shock environments. If the system comes in contact with outer shock disturbance. the system gets critical damage in head-gimbal assembly or disk. This paper describes probabilistic and dynamic shock analysis of head-gimbal assembly in micro MO drives using OFH slider.

• 한국CDE학회논문집
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• 제19권4호
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• pp.316-323
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• 2014

This paper proposes the 3D modeling and simulation technique for predicting the integrated performance of combat vehicle. To consider the practical driving and firing condition of a combat vehicle, the full vehicle model, which can define the six degrees-of-freedom of vehicle motion and various firing angles, is developed. The critical design parameters such as the stiffness and damping coefficient of suspension system are applied to construct the analysis model of vehicle. A simple ballistic model, which incorporates the empirical interior ballistic model and the point mass trajectory model, is built to estimate the firing range and the firing recoil force. To predict the integrated performance and analyze the effect of system parameters, MATLAB/SIM-ULINK model of a combat vehicle for performing the real time simulation is also developed. Several simulation tests incorporating the road bump and the firing recoil force are presented to confirm the effectiveness of the proposed vehicle model.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.570-574
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• 1999

In this paper, by using the electrophoresis, preparation of YBCO superconducting wire deposited on metal Ag base wire was studied with its Properties. YBCO Powder could be prepared by solid state reactions with calcining and sintering processes. Superconducting wire prepared on metal Ag wire used as cathode of deposition base could be also fabricated in the YBCO/acetone-dispersed solution to obtain several tens of re thick films. And then it could be used as superconducting wire for measurement after calcination, sintering and oxygen absorption processes. In the process of film deposition, a catalyst I$_2$added into the suspension solution was very useful for preparing thick film of YBCO, and BaF$_2$ of additive material was also necessary for preparing crack-free wire of YBCO superconductor. As a result, YBCO superconducting wire added 2~3wt.% of BaF$_2$\ulcorner with catalyst, 12 had better deposition condition for uniform and dense YBCO wires, and critical current density, Jc was calculated at the value of 1,458A/$\textrm{cm}^2$(more than 10$^{3}$A/$\textrm{cm}^2$ ,77K, o[T]) of 30${\mu}{\textrm}{m}$ thick sample by 4 point prove method.

• 대한기계학회논문집
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• 제11권3호
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• pp.437-443
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• 1987

본 연구에서는 승차감을 향상시키기 위해 원전석의 진동을 고려한 평면 5자 유도 모델을 사용하여 확정적 노면과 무작위 노면에 대한 시간영역, 주파수영역 해석 과 이에 따른 최적설계를 수행하였다. 최적설계시 목적함수는 주파수영역에서의 운 전석의 가속도 PSD를 구하여 여진동력(absorbed power)을 계산한 다음, 이를 최소화하 면서 차체의 안정성을 제한조건으로 하였다. 또 최적설계의 결과인 운전석의 가속도 rms값과 ISO경계값을 비교하였다. 시간영역에서는 결과를 해당된 운전석의 최대절대 가속도 및 상대변위에 대한 한계치와 비교하였다. 한편으로는 실제 노면 형상을 컴 퓨터로 시뮬레이션하고, 속도에 따른 최적치들 중에서 전체최적치 결정법을 제시하였 다.

• KSBB Journal
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• 제30권6호
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• pp.307-312
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• 2015

Transgenic rice cells using RAmy3D promoter can provide high productivity, and the production of recombinant protein is induced by sugar starvation. In this system, productivity was reduced during the scale-up processes. To ensure the influences of shear stress and oxygen transfer rate, working volume and mixing performances were investigated under various agitation speeds and working volumes. In addition, inoculation methods including suspended cells and filtered cells were compared. Working volumes and shaking speeds were 300, 450 mL and 80, 120 rpm, respectively. Hydrodynamic environment of each condition was measured numerically like mixing time and $k_La$. Good mixing performance and high shear stress were measured at high agitation speed and low volume. The highest level of hCTLA4Ig was 30.7 mg/L at 120 rpm, 300 mL. When conditioned medium was used for inoculation, increased cell growth was noticed during the day 0~4 and decreased slower than filtered cells. Compared with filtered cells, the maximum hCTLA4Ig level reached 37.8 mg/L at 120 rpm, 300 mL and lower protease activity level was observed. In conclusion mixing performance is critical factor for productivity and conditioned medium can have a positive effect on damaged cells caused by hydrodynamic shear stress.

• Smart Structures and Systems
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• 제16권2호
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• pp.243-262
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• 2015

Optimal sensor placement (OSP) is a critical issue in construction and implementation of a sophisticated structural health monitoring (SHM) system. The uncertainties in the identified structural parameters based on the measured data may dramatically reduce the reliability of the condition evaluation results. In this paper, the information entropy, which provides an uncertainty metric for the identified structural parameters, is adopted as the performance measure for a sensor configuration, and the OSP problem is formulated as the multi-objective optimization problem of extracting the Pareto optimal sensor configurations that simultaneously minimize the appropriately defined information entropy indices. The nondirective movement glowworm swarm optimization (NMGSO) algorithm (based on the basic glowworm swarm optimization (GSO) algorithm) is proposed for identifying the effective Pareto optimal sensor configurations. The one-dimensional binary coding system is introduced to code the glowworms instead of the real vector coding method. The Hamming distance is employed to describe the divergence of different glowworms. The luciferin level of the glowworm is defined as a function of the rank value (RV) and the crowding distance (CD), which are deduced by non-dominated sorting. In addition, nondirective movement is developed to relocate the glowworms. A numerical simulation of a long-span suspension bridge is performed to demonstrate the effectiveness of the NMGSO algorithm. The results indicate that the NMGSO algorithm is capable of capturing the Pareto optimal sensor configurations with high accuracy and efficiency.

• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.695-703
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• 2006

The dissolved oxygen level of any cell culture environment has a critical effect on cellular metabolism. Specifically, hypoxia condition decreases cell viability and recombinant protein productivity. In this work, to develop CHO cells producing recombinant protein with high productivity, mammalian expression vectors containing a human tissue-type plasminogen activator (t-PA) gene with hypoxia response element (HRE) were constructed and stably transfected into CHO cells. CHO/2HRE-t-PA cells produced 2-folds higher recombinant t-PA production than CHO/t-PA cells in a $Ba^{2+}-alginate$ immobilized culture, and 16.8-folds in a repeated batch culture. In a non-aerated batch culture of suspension-adapted cells, t-PA productivity of CHO/2HRE/t-PA cells was 4.2-folds higher than that of CHO/t-PA cells. Our results indicate that HRE is a useful tool for the enhancement of protein productivity in mammalian cell cultures.

• 한국수자원학회논문집
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• 제54권8호
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• pp.607-616
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• 2021

본 연구는 가는 모래로 이루어진 하상으로부터 침식된 부유사의 농도분포 계산결과에 차폐효과가 미치는 영향을 살펴보는 것을 목적으로 수행되었다. 하상재료의 입도분포를 고려하여 침식율을 산정할 수 있는 유사이동 모형을 개발하였으며, 측정자료와의 비교를 통해 수치모형의 적용가능성을 검토하였다. 수치모의결과로부터 하상재료 입도분포의 기하표준편차가 1.5보다 작은 경우 차폐효과가 부유사 농도의 연직방향 분포 계산결과에 미치는 영향은 매우 작은 것으로 나타났다. 또한 기하표준편차가 1.5이하인 가는 모래로 이루어진 하상으로부터 침식된 유사 농도를 계산하는 경우, 균일사로 가정 후 대표입경을 바탕으로 농도를 산정하여도 합리적인 결과가 얻어지는 것으로 확인되었다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 춘계학술발표회
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• pp.45-45
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• 2018

We had already reported the successful germination for green pods of purple lady's slipper orchid (Cypripedium macranthos Sw.). The green pod methods is to take immature seeds in green capsules, sterilize the capsule, and take out the sterile seeds. This method, however, needs very critical time of harvest. The critical time of seed harvest changes depending upon the species, condition of the specimen, and climatic influence, and the right time lies between 5 and 12 weeks after fertilization. In this study, the mature seeds were collected after 120-130 days with hand-polination of lady's slipper orchids. Mature seeds are usually dormant and it has to be overcome, either with hormone or storing the seeds near freezing for two or three months to break dormancy. The seeds were first surface sterilized with 70% ethanol and then transferred 1% NaOCl for 10-15 minutes, followed by rinses 3 times with sterilized distilled water. The cypripedium seeds consists of an embryo within a seed coat known as a testa. The testa is water repellent and the seed has a large air space between the embryo and testa so the seed tends to float on water. We had resolved the problems with vacuum pump to soak water into the testa before sterilization. The seeds were placed on liquid or agar solidified germination media. Cultures were incubated at $24{\pm}1^{\circ}C$ in dark. The seeds were germinated in 6-8 weeks in liquid suspension culture (germination percentage over 18%); however, the seeds on agar solidified media took more than 5 months to germinate and the germination percentage less than 5%. The most effective media for liquid culture was 1/4 strength Murashige and Skoog (MS) medium with 50 ml/l coconut water ($4brix^{\circ}$) at pH 5.8.

• 한국산학기술학회논문지
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• 제19권10호
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• pp.16-23
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• 2018

하 폐수 슬러지 발생량의 꾸준한 증가로 인해 폐 슬러지의 효율적인 처리 기술개발이 요구되고 있다. 본 연구에서는 PEF (Pulsed Electric Fields) 기술을 활용하여 슬러지의 가용화를 통한 감량화 가능성을 평가하였다. PEF에 사용되는 스테인레스 재질의 전극에 테프론과 에폭시로 코팅한 후 활성슬러지 혼합액에 전계 펄스를 인가하여 전극 코팅에 따른 가용화 효율을 평가하였다. 또한 인가된 전압의 세기를 6, 12, 15 kV로 변화시켜 가며 가용화 정도를 평가하였다. 에폭시 코팅 전극에서는 MLSS, 용존성-COD, -TN, -TP를 분석한 결과 슬러지의 가용화가 발생하지 않은 것으로 나타났다. 그러나 테프론으로 코팅한 전극에서는 MLSS는 최대 9 % 감소하였고 MLVSS 역시 최대 10 % 감소하였다. 또한 용존성-COD는 최대 496 % 증가하였다. 인가전압 6 kV 하에서는 가용화가 거의 발생하지 않았으나, 12 kV와 15 kV의 전압에서는 슬러지 가용화가 발생한 것으로 나타났다. 또한 슬러지 가용화가 발생한 12 kV와 15 kV의 전압에서는 코로나가 발생한 것으로 보아 슬러지 가용화는 코로나에 의해 유도되었으며, 코로나가 발생하는 임계전압이 존재하는 것으로 판단되었다. 결론적으로 PEF의 인가전압과 적절한 코팅제를 선택하여 코로나 발생을 제어함으로써 슬러지의 가용화를 유도할 수 있음을 확인하였다.