• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2A
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• pp.123-130
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• 2012

A cooling system is indispensable for the fossil and nuclear power plants which produce electricity by rotating the turbines with hot steam. A cycle of the typical cooling system includes pumping of seawater at the intake pump house, exchange of heat at the condenser, and discharge of hot water to the sea. The cooling type of the nuclear power plants in Korea recently evolves from the conventional surface intake/discharge systems to the submerged intake/discharge systems that minimize effectively an intake temperature rise of the existing plants and that are beneficial to the marine environment by reducing the high temperature region with an intensive dilution due to a high velocity jet and density differential at the mixing zone. It is highly anticipated that the future nuclear power plants in Korea will accommodate the submerged cooling system in credit of supplying the lower temperature water in the summer season. This study investigates the approach flow patterns at the velocity caps and discharge flow patterns from diffusers using the 3-D computational fluid dynamics code of $FLOW-3D^{(R)}$. The approach flow test has been conducted at the velocity caps with and without a cap. The discharge flow from the diffuser was simulated for the single-port diffuser and multi-ports diffuser. The flow characteristics to the velocity cap with a cap demonstrate that fish entrainment can significantly be minimized on account of the low vertical flow component around the cap. The flow pattern around the diffuser is well agreed with the schematic diagram by Jirka and Harleman.

• Child Health Nursing Research
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• v.5 no.2
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• pp.185-197
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• 1999

In the family life cycle, the most important task the families with school children should perform is ‘child education’ and ‘socialization’ However, economic stress on poor families with school children presents multiple problems through the shortage of resources necessary for child education and socialization, inappropriateness of family appraisal, and the insufficiency of the control channels for the efficient management of these confined resources and appropriate appraisal. The objectives of this article are : First, to report research on the actual conditions of the poor families in one area of Cheju and on the relevant health welfare policy, and to examine the appropriateness of the direction and the substance of this policy in terms of the intervention in economic stress on the poor families under the categories of resource management and control of appraisal. Second, to analyze qualitative data extracted from the memoirs of single-parent families living in several areas of Korea under the conceptual framework constructed by literature review in order to get a better understanding of the stress which poor families with school children have experienced. And third, to confirm the factors that can be risk factor but, at the same time, strength to these poor families from presented data and to use them as the basic data from which an intervention model can be developed, based on resource management and control of appraisal. The findings of this article are : First, while the number of absolute poor families in one area of Cheju is increasing and, as a result, the danger of the possibility that multiple problems will occur is also growing, the supporting level of the current policy is no more than a direct resource offer and there is no evidence that resource management is being professionally carried out. When it comes to control of appraisal, due to absence of the professional human resources in this matter, policy performances such as technical education training can have a negative impact. Second, a conceptual framework introduced in this article, ; Economic Pressure → Helplessness → Poor self-esteem → Marital Conflict → Parent-Child financial conflict → Inappropriate socialization → Poor child social competence : is partly verified. And third, judging from the results of the qualitative data, it is confirmed that the healing families, having overcome poverty, show several positive characteristics including : hope, strength, and social support. These findings are identified with the factors of resiliency considered above. According to these results, this article suggests the following. The anti -poverty policy in the future should focus not only on a direct resource offer but also on resource management and the control of appraisal that can magnify its effects. In particular, close attention should be paid to school children since they are in the most crucial period for socialization. Moreover, an emotional labor is such an essential resource for intervention that skilled nurses should play pivotal roles.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.3
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• pp.32-42
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• 2022

The strategy to develop a launch vehicle family by bundling multiple rocket engines of a single type has been proven by SpaceX and their reusable fleet comprised of Falcon 9 and Falcon Heavy. In this study, we revisit a potential launch vehicle family out of a 35 tonf-class methalox staged combustion cycle engine and evaluate their utility and performance in various space missions. For example, a Korean version of Falcon 9 can deliver 4.7 tons of payload into 500 km SSO in an expendable mode while the payload is reduced to 2.16 tons in a sea-landing reusable mode. A Korean version of Falcon Heavy can deliver 4.4 tons into GTO when launched from the Naro Space Center, indicating that this common booster core configuration can handle Cheollian 2 albeit the high inclination. Once developed, the same methaloax engine can power the first-stage of smallsat launch vehicles and air launch vehicles.

• Journal of Biosystems Engineering
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• v.7 no.1
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• pp.53-61
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• 1982

As an attempt to reduce the consumption of petroleum resources and to improve the performance of a kerosene engine, a series of experiments was conducted using several kinds of ethanol-kerosene blends under the various compression ratios. The engine used in this study was a single-cylinder, four-cycle kerosene engine having a compression ratio of 4.5. To investigate the feasibility of ethanol-kerosene blends in the original engine, kerosene and blends of 5-percent, 10-percent, and 20-percent-ethanol, by volume, with kerosene were used. And to investigate the feasibility of improving the performance of the kerosene engine, a portion of the cylinder head was cut off to increase the compression ratio up to 5.0 by reducing the combustion chamber volume. Kerosene and blends of 30-percent and 40-percent-ethanol, by volume, with kerosene were used for the modified engine with an increased compression ratio. Variable speed tests at wide-open throttle were also conducted at five speed levels in the range of 1000 to 2200 rpm for each compression ratio and fuel type. Volumetric efficiency, engine torque, and brake specific fuel consumption were determined, and brake thermal efficiency based on the lower heating values of kerosene and ethanol was calculated. The results obtained in the study are summarized as follows: A. Test with the original engine: (1) No abnormal conditions were found when burning ethanol-kerosene blends in the original engine. (2) Volumetric efficiency increased with ethanol concentration in blends. When burning blends of 5-percent, 10-percent, and 20-percent ethanol, by volume, with kerosene, average volumetric efficiency increased 1.6 percent, 2.6 percent, and 4.1 percent respectively, than when burning kerosene. (3) Mean engine torque increased 5.2 percent for 5-percent-ethanol blend, 9.3 percent for 10-percent-ethanol blend, and 11.5 percent for 20-percent-ethanol blend than for kerosene. Increase in engine torque when using ethanol-kerosene blends was due to the improved combustion characteristics of ethanol as well as an increase in volumetric efficiency. (4) Up to ethanol concentration of 20 percent, mean brake specific fuel consumption was nearly constant inspite of the difference in heating value between ethanol and kerosene. (5) Brake thermal efficiency increased 0.3 percent for 5-percent-ethanol blend, 3.8 percent for 10-percent-ethanol blend, and 6.8 percent for 20-percent-ethanol blend than for kerosene. B. Test with the modified engine with an increased compression ratio: (1) When burning kerosene, mean volumetric efficiency, engine torque, and brake thermal efficiency were somewhat lower than for the original engine. (2) Engine torque increased 15.1 percent for 30-percent-ethanol blend and 18.4 percent for 40-percent-ethanol blend than for kerosene. (3) There was no significant difference in brake specific fuel consumption regardless of ethanol concentration in blends. (4) Brake thermal efficiency increased 15.0 percent for 30-percent-ethanol blend and 19. 5 percent for 40-percent-ethanol blend than for kerosene.

• Clinical and Experimental Reproductive Medicine
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• v.46 no.4
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• pp.173-177
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• 2019

Objective: We investigated the clinical characteristics of men with testosterone replacement therapy (TRT)-induced hypogonadism and its effect on assisted reproductive technology (ART) in infertile couples. Methods: This study examined the records of 20 consecutive male patients diagnosed with azoospermia or severe oligozoospermia (< 5 × 10⁶/mL) who visited a single infertility center from January 2008 to July 2018. All patients were treated at a primary clinic for erectile dysfunction or androgen deficiency symptoms combined with low serum testosterone. All men received a phosphodiesterase 5 inhibitor and TRT with testosterone undecanoate (Nebido^®) or testosterone enanthate (Jenasteron^®). Patients older than 50 years or with a chronic medical disease such as diabetes were excluded. Results: The mean age of patients was 37 years and the mean duration of infertility was 16.3 ± 11.6 months. At the initial presentation, eight patients had azoospermia, nine had cryptozoospermia, and three had severe oligozoospermia. Serum follicle-stimulating hormone levels were below 1.0 mIU/mL in most patients. Three ongoing ART programs with female factor infertility were cancelled due to male spermatogenic dysfunction; two of these men had normal semen parameters in the previous cycle. After withholding TRT, serum hormone levels and sperm concentrations returned to normal range after a median duration of 8 months. Conclusion: TRT with high-dose testosterone can cause spermatogenic dysfunction due to suppression of the hypothalamic-pituitary-testicular axis, with adverse effects on infertility treatment programs. TRT is therefore contraindicated for infertile couples attempting to conceive, and the patient's desire for fertility must be considered before initiation of TRT in a hypogonadal man.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.6
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• pp.431-441
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• 2003

This paper presents the design of 32 bit microprocessor for a sequence control using a field programmable gate array(FPGA). The microprocessor was designed by a VHDL with top down method, the program memory was separated from the data memory for high speed execution of sequence instructions. Therefore it was possible that sequence instructions could be operated at the same time during the instruction fetch cycle. In order to reduce the instruction decoding time and the interface time of the data memory interface, an instruction code size was implemented by 32 bits. And the real time debug operation was implemented for easeful debugging the designed processor with a single step run, PC break point run, data memory break point run. Also in this designed microprocessor, pulse instructions, step controllers, master controllers, BM and BCD type arithmetic instructions, barrel shift instructions were implemented for sequence logic control. The FPGA was synthesized under a Xilinx's Foundation 4.2i Project Manager using a V600EHQ240 which contains 600,000 gates. Finally simulation and experiment were successfully performed respectively. For showing good performance, the designed microprocessor for the sequence logic control was compared with the H8S/2148 microprocessor which contained many bit instructions for sequence logic control. The designed processor for the sequence logic showed good performance.

• Applied Microscopy
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• v.12 no.2
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• pp.11-22
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• 1982

The morphological development of Mycoplasma pneumoniae attached to solid surfaces was examined by light and electron microscopies. Critical point drying and carbon replication techniques revealed that during the growth cycle of developing microcolonies, the morphological form coincided with the pH of the culture. M. pneumoniae appeared to have a well defined morphology associated with age of the culture. The organisms were dimorphic, with round cells capable of reproduction and segments consisting of a spindle shaped body with one pointed and one knob-like end. Starting with single cells, there were the following stages in the development of a culture: replication stage through binary fission and segmentation, stage of confluency, and a degeneration stage into rough spherical forms. The round cells appearrd to replicate by binary fission during the lag and early log phases of growth, while spindle segments replicated by segmentation during most of the logarithmic growth. The growth of the filaments and replication of the segments occured at the knob-like ends, showing a type of polarity, and formed a meshwork across the surface. This development could be cycled under favorable growth conditions, but the culture aged and when the conditions became adverse(e.g. pH 6.8 or lower), filamentous cells converted to spherical forms, losing their reproductive capability.

• Nutrition Research and Practice
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• v.13 no.1
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• pp.58-63
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• 2019

BACKGROUND/OBJECTIVES: Telomeres are located at the chromosomal ends and progressively shortened during each cell cycle. Telomerase, which is regulated by hTERT and c-MYC, maintains telomeric DNA sequences. Especially, telomerase is active in cancer and stem cells to maintain telomere length for replicative immortality. Recently we reported that walnut phenolic extract (WPE) can reduce cell viability in a colon cancer stem cell (CSC) model. We, therefore, investigated the effect of WPE on telomere maintenance in the same model. MATERIALS AND METHODS: $CD133^+CD44^+$ cells from HCT116, a human colon cancer cell line, were sorted by Fluorescence-activated cell sorting (FACS) and treated with WPE at the concentrations of 0, 10, 20, and $40{\mu}g/mL$ for 6 days. Telomere lengths were assessed by quantitative real-time PCR (qRT-PCR) using telomere specific primers and DNA extracted from the cells, which was further adjusted with single-copy gene and reference DNA ($ddC_t$). Telomerase activity was also measured by qRT-PCR after incubating the PCR mixture with cell protein extracts, which was adjusted with reference DNA ($dC_t$). Transcriptions of hTERT and c-MYC were determined using conventional RT-PCR. RESULTS: Telomere length of WPE-treated cells was significantly decreased in a dose-dependent manner ($5.16{\pm}0.13$ at $0{\mu}g/mL$, $4.79{\pm}0.12$ at $10{\mu}g/mL$, $3.24{\pm}0.08$ at $20{\mu}g/mL$ and $3.99{\pm}0.09$ at $40{\mu}g/mL$; P = 0.0276). Telomerase activities concurrently decreased with telomere length ($1.47{\pm}0.04$, $1.09{\pm}0.01$, $0.76{\pm}0.08$, and $0.88{\pm}0.06$; P = 0.0067). There was a positive correlation between telomere length and telomerase activity (r = 0.9090; P < 0.0001). Transcriptions of both hTERT and c-MYC were also significantly decreased in the same manner. CONCLUSION: In the present cell culture model, WPE reduced telomere maintenance, which may provide a mechanistic link to the effect of walnuts on the viability of colon CSCs.

• Korean Journal of Remote Sensing
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• v.38 no.3
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• pp.251-263
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• 2022

This paper presents an idea of ScanSAR image formation. For image formation of ScanSAR that utilizes the burst mode for raw signal acquisition, most conventional single burst methods essentially require a step of azimuth stitching which contributes to radiometric and phase distortions to some extent. Time-domain cross correlation could replace SPECAN which is most popularly used for ScanSAR processing. The core idea of the proposed method is that it is possible to relieve the necessity of azimuth stitching by an extension of Doppler bandwidth of the reference function to the burst cycle period. Performance of the proposed method was evaluated by applying it to the raw signals acquired by a spaceborne SAR system, and results satisfied all image quality requirements including 3 dB width, peak-to-sidelobe ratio (PSLR), compression ratio,speckle noise, etc. Image quality of ScanSAR is inferior to that of Stripmap in all aspects. However, it is also possible to improve the quality of ScanSAR image competitive to that of Stripmap if focused on a certain parameter while reduced qualities of other parameters. Thus, it is necessary for a ScanSAR processor to offer a great degree of flexibility complying with different requirements for different applications and techniques.

• Journal of Life Science
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• v.26 no.12
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• pp.1383-1391
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• 2016

Anti-estrogen drugs such as tamoxifen have been used for treating patients with ER-positive, early breast cancer. However, resistance to anti-estrogen treatment is inevitable in most patients. Breast cancer anti-estrogen resistance-3 (BCAR3) has been identified as the protein responsible for the induction of tamoxifen resistance in estrogen-dependent human breast cancer. We have previously reported that BCAR3 regulates the cell cycle progression and the signaling pathway of EGF and insulin leading to DNA synthesis. In this study, we investigated the functional role of BCAR3 in regulating c-Jun transcription in non-tumorigenic human breast epithelial MCF-12A cells. A transient transfection of BCAR3 increased both the mRNA and protein of c-Jun expression, and stable expression of BCAR3 increased c-Jun protein expression. The overexpression of BCAR3 directly activated the promoter of c-jun, AP-1, and SRE but not that of $NF-{\kappa}B$. Furthermore, single-cell microinjection of BCAR3 expression plasmid in the cell cycle-arrested MCF-12A cells induced c-Jun protein expression, and co-injection of dominant negative mutants of Ras, Rac, and Rho suppressed the transcriptional activity of c-Jun in the presence of BCAR3. Furthermore, stable expression of BCAR3 increased the proliferation of MCF-12A cells. The microinjection of inhibitory materials such as anti-BCAR3 antibody and siRNA BCAR3 inhibited EGF-induced c-Jun expression but did not affect IGF-1 induced upregulation of c-Jun. Taken together, we propose that BCAR3 plays a crucial role in c-Jun protein expression and cell proliferation and that small GTPases (e.g., Ras, Rac, and Rho) are required for the BCAR3-mediated activation of c-Jun expression.