• Corrosion Science and Technology
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• v.2 no.1
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• pp.7-11
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• 2003

Photoelectrochemical response and electrochemical impedance behavior was investigated for passive film formed on sputter-deposited Cr alloy in $0.1kmol{\cdot}m^{-3}$. Photoelectrochemical action spectrum could be separated into two components, which were considered to be derived from $Cr_2O_3$ ($E_g\sim3.6eV$) and $ Cr(OH)_3 $ ($E_g\sim2.5eV$). The band gap energy, $E_g$, of each component was almost constant for various applied potentials. polarization periods and alloying additives. The photoelectrochemical response showed negative photo current for most potentials in the passive region. Therefore, the photo current apparently exhibited p-typesemiconductor behavior. On the other hand, Mort-Schottky plot of the capacitance showed positive slope, which means that passive film formed on Cr alloy has n-type semiconductor property. These apparently conflicting results are rationally explained assuming that the passive film on Cr alloy formed in the acid solution has n-type semiconductor property with a fairly deep donor level in the band gap and forms an accumulation layer in the most of potential region in the passive state.

• Journal of Applied Reliability
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• v.15 no.2
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• pp.108-123
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• 2015

Test and Evaluation (T&E) have been verifying the level of it's technological skill and the needed operational status of the development weapons. If the overall spectrum of test and evaluation is fulfilled substantially in the production & deployment, the needed level of the weapon system will be enhanced and also the reliability status will become higher considerably. We can know currently these issues through the mass media and all kinds of the news regarding the defense industry and programs. And so this article have studied the method of enhancing reliability of the test and evaluation, the 6 variables were selected through the discussion of the professional group. The the test and evaluation group needs consistently the professional training systems. After DT&E, we have to the event to verify the technical level of the development systems. We have to take the high level of the kinds of the environmental test. Scientific methods like system engineering will be adapted in process of the test and evaluation. The number of suitable test prototype in the test and evaluation is analysed more systematically. And we need to establish the standardization of the test and evaluation. If 6 variables are well analysed and adapted in the working field, the reliability of the test and evaluation will be considerably, the defense industry will take the chance to develope the future-oriented.

• Korean Journal of Weed Science
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• v.9 no.3
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• pp.230-237
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• 1989

This research was carried out to investigate the influences of temperature and light on the herbicidal activity of oxyfluorfen, oxadiazon and paraquat. Increased temperature from 10 to $35^{\circ}C$ resulted in increase of herbicidal activity in whole plants or leaf discs treated with herbicides. It seemed that temperature affected herbicide penetration into and reaction to the action site rather than appearance process of herbicidal activity (maybe membrane peroxidation after being absorbed. The activity of compounds tested increased with increased light intensity. Paraquat showed similar activities regardless of light qualities but oxyfluorfen and oxadiazon showed the highest activities in blue light spectrum, indicating that they seemed to be closely related to chlorophyll biosynthesis rather than carotenoid biosynthesis or electron transport systems of photosynthesis and respiration.

• Natural Product Sciences
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• v.12 no.4
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• pp.175-192
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• 2006

Screening for the cytotoxicity from plant origin is the first stage for anti-cancer drug development. A variety of terpenoids with exomethylene, epoxide, allyl, $\alpha,\beta-unsaturated$ carbonyl, acetylenes, and $\alpha-methylene-\gamma-lactone$ induces apoptosis and/or differentiation as well as cytotoxicity through the ROS signal transduction pathways. These are found among monoterpenes, sesquiterpenes, triterpenes, flavonoids, coumarins, diarylheptanoids, and even organosulfuric compounds. The most essential characteristics of natural cytotoxic substances is to possess the strong electrophilicity that is susceptible to nucleophilic biomolecules in the cell. Thiol-reductants and superoxide dismutase can block or delay apoptosis. Thus, ROS and the resulting cellular redox-potential changes can be parts of the signal transduction pathway during apoptosis. Disturbance of the balance of oxireduction by the pigment of natural quinones also caused the induction of the differentiation and apoptosis. Saponins with the cytotoxicity are restricted to their monodesmosides, rather than to bisdesmosides. Those saponins exhibited calcium ion-mediated apoptosis in addition to cytotoxicity whereas they showed also differentiation without extracellular calcium ion. The properties on cytotoxicity, apoptosis, and differentiation were assumed to depend on resultant oxidative stress to the cells. In this review, we describe a spectrum of cytotoxic compounds with various action mechanisms.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.280.2-286
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• 1998

Flood is the main natural disaster mostly in the world. It is a care problem to prevent flood disaster generally. The frequency of flood disaster is high and the distributing field is wide, the 50 percent population and 70 percent properties distribute at the threaten field of flood disaster in China. Flood disaster has caused a huge amount of economical losses and these losses have an increasing trend. Along with the development of reducing natural disaster action, it has become one of the most attentive problems for monitoring flood, preventing flood and forecasting flood efficiently. Remote sensing has the characteristics of large spatial observing areas, wide spectrum ranges, and imaging far away from the targets, imaging capabilities all weather. Spatial remote sensing information, which records the full, processes of the disaster's occurrence and development in real-time. It is a scientific basis for management, planning and decision-making. Through systemic analyzing the RS monitoring theory, based on compounding RS information, the technology and method of monitoring flood disaster are studied.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.80-80
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• 1995

T4 Endonuclease V (Mw 16,000) acts as a repair enzyme for UV induced pyrimidine dimers in DNA. Many researchers have studied the biochemical characteristics of the enzyme. However the precise action mechanism of T4 endo V has not fully elucidated yet. In our laboratory NMR spectroscopy technique is being used for the structural study of T4 endo V. Because of its low temperature stability and high content of ${\alpha}$-helix, the conventional $^1$H NMR technique was inapplicable. Therefore we utilized stable isotope labeling technique and so far prepared about 10 amino acid specific labeled proteins. The HSQC spectra of amino acid specific labeled proteins will help us to interpret the triple resonance 3D, 4D data which are under processing, We also studied the behaviors of specific amino acid residues whose roles might be critical. When the enzyme labeled by $\^$15/N-Thr was mixed with the substrate oligonucleotide (semispecific -TT- sequence), one crosspeak in its HSQC spectrum was completely desappeared, which means that one of seven Thr residues is in the binding site of the enzyme with DNA, This result is well consistent with previous report that implicated the Thr 2 residue in the activity of the enzyme. Similar studies were carried on the behaviors of Arg and Tyr residues.

• Biomolecules & Therapeutics
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• v.15 no.3
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• pp.192-198
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• 2007

Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a major constituent of rhubarb. Although it has been claimed to have a wild spectrum of therapeutic value, its side effects, especially in human kidney cells have not been well characterized. In this study, we have carried out in vitro genetic toxicity test of emodin and microarray analysis of differentially expressed genes in response to emodin. The result of Ames test showed mutations with emodin treatment in base substitution strain TA1535 both with and without exogenous metabolic activation. Likewise, emodin showed mutations in frame shift TA98 both with and without exogenous metabolic activation. The result of COMET assay in L5178Y cells with emodin treatment showed DNA damage both with and without exogenous metabolic activation. Emodin did not increase micronuclei in CHO cells both with and without exogenous metabolic activation. 150 Genes were selected as differentially expressed genes in response to emodin by microarray analysis and these genes would be candidate biomarkers of genetic toxic action of emodin.

• Biomolecules & Therapeutics
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• v.15 no.3
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• pp.199-204
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• 2007

Carbamates have excellent insecticidal activities against a broad spectrum of insects. They possess knocking-down, fast-killing, and systemic effects, however, they are toxic to mammals. In this study, we have carried out in vitro genetic toxicity test of methylcarbamate and microarray analysis of differentially expressed genes in response to methylcarbamate. Methylcarbamate did not show mutations in base substitution strain TA1535 both with and without exogenous metabolic activation. Methylcarbamate did not show mutations in frame shift TA98 both with and without exogenous metabolic activation. Methylcarbamate showed DNA damage based on single cell gel/comet assay in L5178Y cells both with and without exogenous metabolic activation. Methylcarbamate did not increase micronuclei in CHO cells both with and without exogenous metabolic activation. Microarray analysis of gene expression profiles in L5178Y cells in response to methylcarbamate selected differentially expressed 132 genes that could be candidate biomarkers of genetic toxic action of methylcarbamate.

• Nuclear Engineering and Technology
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• v.31 no.1
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• pp.17-28
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• 1999

A thermal-hydraulic analysis is conducted on the loss-of-coolant-accident (LOCA) during shutdown operation of YGN Units 3/4. Based on the review of plant-specific characteristics of YGN Units 3/4 in design and operation, a set of analysis cases is determined, and predicted by the RELAP5/MOD3.2 code during LOCA in the hot-standby mode. The evaluated thermal-hydraulic phenomena are blowdown, break flow, inventory distribution, natural circulation, and core thermal response. The difference in thermal-hydraulic behavior of LOCA at shutolown condition from that of LOCA at full power is identified as depressurization rate, the delay in peak natural circulation timing and the loop seal clearing (LSC) timing. In addition, the effect of high pressure safety injection (HPSI) on plant response is also evaluated. The break spectrum analysis shows that the critical break size can be between 1% to 2% of cold leg area, and that the available operator action time for the Sl actuation and the margin in the peak clad temperature (PCT) could be reduced when considering uncertainties of the present RELAP5 calculation.

• The Journal of Korean Medicine
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• v.23 no.1
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• pp.50-60
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• 2002

Objectives: Sunghyangjunggisan (SHJS) is a commonly prescribed drug with a wide neuropharmacological spectrum. The water extracts of SHJS were found to be protective against neurotoxicity elicited by deprivation of serum and glucose. Methods: The morphological examination and Hoechst staining of nucleus also clearly showed that the extracts attenuated the cell shrinkage, membrane blebbing, representing typical neuronal apoptotic phenomena and nucleosome-sized fragmentation under the microscope in PC 12 rat pheochromocytoma cells. Results: Activation of protein kinase A (PKA) with dibutyl-cAMP and forskolin also protected during glucose deprivation, although it was not additive with the effect provided by phorbol ester. Interestingly, treatment with the protein kinase A inhibitor, KT5720, was not neuroprotective in the presence of SHJS. Electrophoretic mobility shift assays were used to characterize the neuroprotective binding of nuclear proteins to consensus sequences for AP-l, nuclear factor kappa B ($NF-{\kappa}B$) after glucose deprivation. When PC 12 cells are induced to undergo apoptosis by serum deprivation, AP-l and $NF-{\kappa}B$ DNA binding activity transiently increases to a slight degree. This stimulation is blocked by the water extracts of SHJS. The site of action of the drugs appeared to involve specific inhibition of AP-1 and nuclear factor kB binding activity. Conclusions: Taken together, these results suggested the possibility that the extracts of SHJS might provide a neurotrophic-like activity in PC 12 cells.