• 한국재료학회지
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• 제29권12호
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• pp.798-803
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• 2019

The self-discharge behavior of zinc-air batteries is a critical issue induced by corrosion and hydrogen evolution reaction (HER) of zinc anode. The corrosion reaction and HER can be controlled by a gelling agent and concentration of potassium hydroxide (KOH) solution. Various concentrations of KOH solution and polyacrylic acid have been used for gel electrolyte. The electrolyte solution is prepared with different concentrations of KOH (6 M, 7 M, 8 M, 9 M). Among studied materials, the cell assembled with 6 M KOH gel electrolyte exhibits the highest specific discharge capacity and poor capacity retention. Whereas, 9 M KOH gel electrolyte shows high capacity retention. However, a large amount of hydrogen gas is evolved with 9 M KOH solution. In general, the increase in concentration is related to ionic conductivity. At concentrations above 7 M, the viscosity increases and the conductivity decreases. As a result, compared to other studied materials, 7 M KOH gel electrolyte is suitable for Zn-air batteries because of its higher capacity retention (92.00 %) and specific discharge capacity (351.80 mAh/g) after 6 hr storage.

• 대한세포병리학회지
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• 제7권2호
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• pp.177-184
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• 1996

Intraoperative cytologic examination of intracranial tumors using crush preparation provides useful information in operative decision making. The diminutive nature of many biopsy specimens, particularly those obtained by stereotactic neurosurgical procedures emphasizes the importance of combining the cytologic smear method with conventional frozen section interpretation. The great advantage of the cytologic smear method resides in its suitability for the study of minute fragments of tissue, allowing retention of the majority of the specimen for optimal processing. We present the cytologic features of 3 cases of intracranial germ cell tumors(2 germinomas and 1 endodermal sinus tumor), using crush preparation during intraoperative diagnosis and compare them with histologic findings. The cytologic features of the germ cell tumors were similar to those of the respective gonadal counterparts. The cytologic differential diagnosis of both types of germ cell tumors is described.

• 반도체디스플레이기술학회지
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• 제5권1호
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• pp.17-20
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• 2006

This paper presents of a new type of memory cell that could potentially replace both DRAM and flash memory. The proposed device cell operates by sensing the state of about 1,000 electrons trapped between unique insulating barriers in the channel region of the upper transistor. These electrons are controlled by a side gate on the transistor, and their state in turn controls the gate of the larger transistor, providing signal gain within the memory cell. It becomes faster and more reliable memory with lower operation voltage. Moreover, the use of a multiple tunnel junction (MTJ) fur the vertical transistor can significantly improve the data retention and operation speed.

• Plant Biotechnology Reports
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• 제2권1호
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• pp.1-6
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• 2008

Cotyledonary leaves of tomato cv. Megha were transformed with the hepatitis B virus 's' gene, which encodes surface antigen. Six plant expression cassettes (pHBS, pHER, pEFEHBS, pEFEHER, pSHER and pEFESHER) were used to assay the possible expression levels by agroinfiltration. The maximum transient expression level of 489.5 ng/g D.W. was noted in pEFEHER-infiltrated cotyledonary leaves. Transgenic tomato plants with pEFEHBS and pEFEHER expression cassettes were regenerated and characterized by molecular analysis. The expression of the antigen in the fruits was confirmed by RT-PCR and ELISA analysis. This is the first report on the expression of hepatitis B surface antigen in tomato.

• BMB Reports
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• 제29권4호
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• pp.314-320
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• 1996

The effects of non-cytotoxic concentrations of tamoxifen, verapamil, and trifluoperazine on doxorubicin cytotoxicity in five human breast cancer cell lines were studied. A non-cytotoxic concentration of tamoxifen resulted in enhanced doxorubicin cytotoxicity in HTB-123, HTB-26, and MCF-7. In these three cell lines, a combination of tamoxifen with verapamil resulted in even more increased doxorubicin cytotoxicity. Addition of verapamil or trifluoperazine alone did not influence the doxorubicin cytotoxicity significantly. Only in HTB-19 did coincubation with verapamil increase the doxorubicin cytotoxicity. In HTB-123, combination of tamoxifen with trifluoperazine increased the doxorubicin cytotoxicity significantly. In the cell lines where co-incubation with tamoxifen increased doxorubicin sensitivity, high estrogen receptor expression was detected. However, HTB-20, where tamoxifen did not enhance doxorubicin action, was also estrogen receptor positive. None of the cell lines had multidrug resistance related drug efflux and drug retention was not increased by the treatment with tamoxifen and verapamil. Cell cycle traverses were not altered by incubation with tamoxifen, verapamil or combinations thereof. These observatlons suggest mechanism of non-cytotoxic concentrations of tamoxifen and verapamil on doxorubicin cytotoxicity may involve one or more other cellular processes besides those of interference of estrogen binding to its receptor, cell cycle perturbation, or drug efflux blocking.

• 한국지반공학회지:지반
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• 제9권1호
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• pp.59-68
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• 1993

In deep excavations for creation of underground spaces, it would be difficult to predict earth pressure, especially multilayered ground including rock strata. The earth pressures and displacements on the retention walls are measured by load cell, strain gauge and inclinometer which were installed at struts or anchors at 4 deep excavation sites in Seoul area. In this paper, the measured earth pressure from the struts or anchors are compared with Peck's empirical values, and the coefficient of the earth pressures for each strata and horizontal wall displacement are investigated. The coefficient of earth pressure distribution, a(0.65zka), in the flexible and the rigid walls was about 74% and 88% of Peck's value respecitively. The measured earth pressure distributions for the 4 sites showed about 70%∼80% of Peck's empirical values and the average earth pressure coefficients based on the measured data were 0.3 for the felted layer, 0.23 for the weathered rock and 0.19 for the weak rock. The maximum w리1 displacements were found to be less 0.2% of excavation depth.

• Transactions on Electrical and Electronic Materials
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• 제5권4호
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• pp.148-152
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• 2004

The direct lateral profile and retention characteristics of locally trapped-charges in the nitride layer of the two-bit polysilicon-oxide-nitride-oxide-silicon (SONOS) memory are investigated by using the charge pumping method. After charges injection at the drain junction region, the lateral diffusion of trapped charges as a function of retention time is directly shown by the results of the local threshold voltage and the trapped-charges quantities.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
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• pp.325-328
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• 2000

The control of the data retention time is a main issue for realizing future high density dynamic random access memory. In this paper, we propose the new implantation scheme by gate-related ion beam shadowing effect and buffer-enhanced $\Delta$ Rp increase using buffered N- implantation with tilt and 4X-rotation that is designed on the basis of the local-field-enhancement model of the tail component. We report an excellent tail improvement of the retention time distribution attributed to the reduction of electric field across the cell junction due to the redistribution of N- concentration which is intentionally caused by Ion Beam Shadowing and Buffering Effect using tilt implantation with 4X-rotation.

• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2499-2510
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• 2020

We performed 3-D (3-dimensional) IVR (In-Vessel Retention) natural convection experiments simulating the oxide layer in the three-layer configuration, varying the aspect ratio (H/R). Mass transfer experiment was conducted based on the analogy to achieve high Ra_H's of 1.99 × 10¹²-6.90 × 10¹³ with compact facilities. Comparisons with 2-D (2-dimensional) experiments revealed different local heat transfer characteristics on upper and lower boundaries of the oxide layer depending on the H/R. For the 3-D shallow oxide layer, the multi-cell flow patterns appeared and the number of cells was considerably increased with the H/R decreases, which differs with the 2-D experiments that the number of cells was independent on H/R. Thus, the enhancement of the downward heat transfer and the mitigation of the focusing effect were more noticeable in the 3-D experiments.

• 대한의용생체공학회:의공학회지
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• 제17권3호
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• pp.355-364
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• 1996

Construction of the stable monolayer of endothelial cells onto physicochemically modified polymeric surFace is one of the appropriate method to develop the small caliber vascular graft with the long-term patency. In this study, we constructed the monolayer of endothelial cells on the fibronectin rind the extracellular matrix-coated polyurethane surface derived from human fibroblast cells. To elucidate the adhesion strength of endothelial cells on the extracellular matrix-coated polyurethane, a laminar flow chamber apparatus was developed to exposure the shear stress on the apical membrane of ondothelial cells. Endothelial cells show the strongest adhesion after two days of seeding onto the fibronectin-coated polyurethane surface, whereas endothelial cells on the extracellular matrix derived from the human flbroblast cells show the minimal doubling time of cellular growth.