• Asian Pacific Journal of Cancer Prevention
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• v.14 no.3
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• pp.1803-1806
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• 2013

Purpose: Carbohydrate antigen (CA) 242 is inversely related to prognosis in many cancers. However, few data regarding CA 242 in esophageal cancer (EC) are available. The aim of this study was to determine the prognostic value of CA 242 and propose an optimum cut-off point in predicting survival difference in patients with esophageal squamous cell carcinoma (ESCC). Methods: A retrospective analysis was conducted of 192 cases. A receiver operating characteristic (ROC) curve for survival prediction was plotted to verify the optimum cuf-off point. Univariate and multivariate analyses were performed to evaluate prognostic parameters for survival. Results: The positive rate for CA 242 was 7.3% (14/192). The ROC curve for survival prediction gave an optimum cut-off of 2.15 (U/ml). Patients with CA 242 ${\leq}$ 2.15 U/ml had significantly better 5-year survival than patients with CA 242 >2.15 U/ml (45.4% versus 22.6%; P=0.003). Multivariate analysis showed that differentiation (P=0.033), CA 242 (P=0.017), T grade (P=0.004) and N staging (P<0.001) were independent prognostic factors. Conclusions: Preoperative CA 242 is a predictive factor for long-term survival in ESCC, especially in nodal-negative patients. We conclude that 2.15 U/ml may be the optimum cuf-off point for CA 242 in predicting survival in ESCC.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.49-55
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• 2015

In this study, among in various scenarios of the duration degradation of the fuel cell, countermeasures for the cathode carbon carrier oxidation and the deactivation of catalyst by hydrogen / air interface formation have been studied. so the system was applied to the air cutoff valve. In terms of the component, the cold start performance, electrical stability, the airtight performance were mainly designed and their performance was confirmed. And in terms of the system, the air electrode flow is blocked off, so the oxygen concentration drops when system is powered off, As a result, By reducing unit cell voltage which affect the durability of the fuel cell reached up to 0.8V, the improved durability of the fuel cell was confirmed.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2198-2203
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• 2008

Hydrogen which can be produced through reforming process of hydrocarbon fuel is supplied into anode side of fuel cell system. In the fuel cell, only 70% of hydrogen is consumed through electrochemical reaction and 30% hydrogen passed by as anode off gas. When electrical output of fuel cell is within range of 1.0 to 3.0kW, burner for the reformer uses only anode off gas. And it uses mixture gas of anode off gas and LNG within range of 3.5 to 5.0kW in electrical output. CHEMKIN 4.1 program's Premixed code was used for calculating the properties of each gas. Results show that burning velocity and adiabatic flame temperature are 34.4cm/s, 1681.7K at equivalence ratio 0.8 within range of 1.0kW to 3.0kW and for cases of 3.5kW, 5.0kW, of electrical output, burning velocity and adiabatic flame temperature represent 30.5, 29.8cm/s and 1722.8, 1750K respectively. CO shows the lowest emission index at equivalence ratio 0.8 and NOx reveals the highest emission index at equivalence ratio 1.

• Progress in Superconductivity and Cryogenics
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• v.24 no.2
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• pp.27-38
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• 2022

Urban air mobility (UAM) has recently attracted lots of attention as a solution to urban centralization and global warming. Electric vertical take-off and landing (eVTOL) is a concept that emerges as one of the promising and clean technologies for UAM. There are two difficult challenges for eVTOL aircraft to solve. One is how to improve the weight efficiency of aircraft, and the other is how to complete long-range missions for UAM's flight scenarios. To approach these challenges, we propose a consolidated concept design of battery-fuel cell hybrid tiltrotor aircraft with a liquid hydrogen (LH₂) fuel tank. The efficiency of a battery-fuel cell hybrid powertrain system on the designed eVTOL aircraft is compared to that of a battery-only powertrain system. This paper shows how much payload can increase and the flight scenario can be improved by hybridizing the battery and fuel cell and presenting a detailed concept of a cryogenic storage tank for LH₂.

• Journal of Yeungnam Medical Science
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• v.29 no.1
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• pp.14-18
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• 2012

Background: The purpose of this study was to differentiate chromophobe renal cell carcinoma and clear cell renal cell carcinoma on helical CT. Methods: The CT images of 9 patients histopathologically proven to have chromophobe renal cell carcinoma and 20 patients with clear cell renal cell carcinoma were reviewed. The tumor sizes, margins, enhancement degrees and patterns, presence or absence of calcification, and tumor spread patterns (including perinephric changes, venous invasion, lymphadenopathy, and distant metastasis) were compared. Results: All the chromophobe renal cell carcinomas showed well-demarcated margins. Thechromophobe renal cell carcinomas showed milder enhancements than the clear cell renal cell carcinomas. The sensitivity and specificity for differentiating the chromophobe renal cell carcinoma from the clear cell renal cell carcinoma were 100 and 88%, respectively, when 101 Hounsfield units was used as the cut-off value in the corticomedullary phase, and 95 and 100% when a less-than-three-time enhancement change was used as a cut-off value in the corticomedullary phase (p<0.05). The chromophobe renal cell carcinomas (67%) tended to show a homogeneous enhancement whereas the clear cell renal cell carcinomas (85%) usually showed a heterogeneous enhancement (p<0.05). Statistical analysis revealed that the frequencies of the tumor spread pattern and calcification in the two subtypes didnot differ significantly (p>0.05). Conclusion: The CT findings of the chromophobe renal cell carcinomascompared to those of the clear cell renal cell carcinomas showed that there were mild enhancements in the corticomedullary phase, homogeneous enhancements, and well-demarcated margins.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.4
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• pp.330-337
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• 2015

A bucket-brigade is a way of transporting items where items are passed from one person to the next. The operation of the bucket brigade imitates the cooperative behavior of ants when brood, food or other resources are moved. Koo (2009) presented a bucket brigade-based assembly cell where each worker follows a simple rule: perform assembly operations on a product until the next worker downstream takes it over; then go back to the previous worker upstream to take over a new assembly job. In this way, the flow line is self-balanced without any predetermined job assignment. However, there are some productivity losses related to hand-off and blocking. This paper examines the hand-off and blocking losses and presents a new bucket brigade-based assembly cell where working areas for each assembler is restricted with the help of buffer interfaces. Simulation experiments are used to validate the performance of the new assembly system.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1580-1583
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• 2008

We propose an optical configuration for a vertical alignment (VA) liquid crystal (LC) cell to eliminate the off-axis light leakage in the dark state. The proposed compensation configuration consists of a positive A-film, a positive C-film and a negative C-film. The optical design is performed on a Poincar$\acute{e}$ sphere. This configuration has a better tolerance to the wavelength dispersion, as the polarization trace could self-compensate it. From calculations, we show that the proposed VA LC cell can improve the viewing angle characteristics by compensating for the light leakage in the diagonal direction.

• The KIPS Transactions:PartC
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• v.9C no.3
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• pp.385-398
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• 2002

To accommodate the increasing number of mobile terminals in the limited radio spectrum, wireless systems have been designed as micro/picocellular architectures for a higher capacity. This reduced coverage area of a cell has caused a higher rate of hand-off events, and the hand-off technology for efficient process becomes a necessity to provide a stable service. Population-based Bandwidth Reservation(PBR) Scheme is proposed to provide prioritized handling for hand-off calls by dynamically adjusting the amount of reserved bandwidth of a cell according to the amount of cellular traffic in its neighboring cells. We analyze the performance of the PBR scheme according to the changes of a fractional parameter, f, which is the ratio of request reservation to the total amount of bandwidth units required for hand-off calls that will occur for the next period. The vague of this parameter, f should be determined based on QoS(Quality of Service) requirement. To meet the requirement the value of Parameter(f) must be able to be adjusted dynamically according to the changing traffic conditions. The best value of f can be determined by a function of the average speed of mobile stations, average call duration, cell size, and so on. This paper considers the average call duration and the cell size according to the speed of mobile stations. Although some difference exists as per speed, in the range of 0.4 $\leq$ f $\leq$ 0.6, Blocking Probability, Dropping Probability and Utilization show the best values.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.533-540
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• 2013

Purpose: To investigate the synaptic pattern of NMDA glutamate receptor subtype NMDA R1 on the dendritic arbors of ON-OFF direction-selective retinal ganglion cells (DS-RGSs) in developing [(5,10) days postnatal (PN)] mouse retina. Methods: ON-OFF DS-RGCs were injected with Lucifer yellow and the cells were identified by their characteristic morphology. To identify glutamatergic excitatory input from bipolar cell, we used a marker for the membrane traffic motor protein kinesin. Results: We identified DS-RGCs in P5, and P10 mouse retina. The immunofluorescence labeling of NMDA R1 was most prominent in the IPL. Our results showed that their presence upon the entire dendritic arbor of ON-OFF DS-RGCs is without any evidence of asymmetry, which would predict direction selectivity. Conclusions: The glutamatergic input from bipolar cell reveals symmetry pattern in all periods of P5, and P10. The results may suggest that direction selectivity not lies in the specific pattern of NMDA R1 receptors.

• Journal of Electrochemical Science and Technology
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• v.13 no.4
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• pp.472-478
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• 2022

Solar energy harvesting is practiced by various nations for the purpose of energy security and environment preservation in order to reduce overdependence on oil. Converting solar energy into electrical energy through Photovoltaic (PV) module can take place either in on-grid or off-grid applications. In recent time Lithium battery is exhibiting its presence in on-grid applications but its role in off-grid application is rarely discussed in the literature. The preliminary capacity and Peukert's study indicated that the battery quality is good and can be subjected for life cycle test. The capacity of the battery was 10.82 Ah at 1 A discharge current and the slope of 1.0117 in the Peukert's study indicated the reaction is very fast and independent on rate of discharge. In this study Lithium Iron Phosphate battery (LFP) after initial characterization was subjected to life cycle test which is specific to solar off-grid application as defined in IEC standard. The battery has delivered just 6 endurance units at room temperature before its capacity reached 75% of rated value. The low life of LFP battery in off-grid application is discussed based on State of Charge (SOC) operating window. The battery was operated both in high and low SOC's in off-grid application and both are detrimental to life of lithium battery. High SOC operation resulted in cell-to-cell variation and low SOC operation resulted in lithium plating on negative electrode. It is suggested that to make it more suitable for off-grid applications the battery by default has to be overdesigned by nearly 40% of its rated capacity.