• Korean Journal of Optics and Photonics
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• v.28 no.5
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• pp.241-249
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• 2017

This paper presents the design and evaluation of the optical system for an uncooled thermal-imaging camera. The operating wavelength range of this system is from $7.7{\mu}m$ to $12.8{\mu}m$. Through optimization, we have obtained a LWIR (Long Wave Infrared) optical system with a focal length of 5.44 mm, which consists of four aspheric surfaces and two diffractive surfaces. The f-number of the optical system is F/1.2, and its field of view is $90^{\circ}{\times}67.5^{\circ}$. The hybrid lens was used to balance the higher-order aberrations, and its diffraction properties were evaluated by scalar diffraction theory. We calculated the polychromatic integrated diffraction efficiency, and the MTF drop generated by background noise. We have evaluated the thermal compensation of a LWIR fixed optical system, which is optically passively athermalized to maintain MTF performance in the focal depth. In conclusion, these design results are useful for an uncooled thermal-imaging camera.

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.165-171
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• 1993

The effects of the iron ions for the light-induced mitochondrial $F_0F_1-ATPase$ of Lentinus edodes was studied. The enzyme activity was stimulated up to 202% by 0.1 mM $Fe^{2-}$ ion, but was inhibited by $Fe^{3+}\;and\;Mg^{2+}$. In the presence of 0.5 mM $Mg^{2+}$, the activity also increased 32% by 0.1 mM $Fe^{2+}$ ion, and decreased to a similar extent by $Fe^{3+}$ ion than by only $Fe^{3+}$ ion. Also, the activity was inhibited 53% by 5.0 mM $Fe^{2-}$ ion in the presence of 0.5 mM $Mg^{2+}$ ion and various concentration of $Fe^{3+}$ ion(mM). These results showed that $Fe^{2+}$ strongly stimulated the enzyme activity and its role for the enzyme was independent of $Mg^{2+}$ ion, but was dependent of $Fe^{3+}$ ion. From inactivation of the enzyme by addition of metal chelating agent, EDTA, it is suggested that the enzyme is to be metalloenzyme. The optimal pH and temperature of the enzyme in the presence of 0.1 mM $Fe^{2+}$ was 7.6 and $63^{\circ}C$, respectively.

• Journal of the military operations research society of Korea
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• v.34 no.2
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• pp.163-174
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• 2008

The military is an organization where reliability and availability take much more importance than in any other organization. And, in line with a recent trend of putting emphasis on 'system readiness', not only functions but also availability of a weapon system has become one of achievement targets. In this regard, the military keeps spares for important facility and equipment, which is called as Maintenance Float (M/F), in order to enhance reliability and availability in case of an unforeseen event. The military has calculated yearly M/F requirements based on the number of equipment and utilization rate. However, this method of calculation has failed to meet the intended targets of reliability and availability due to lack of consideration on the characteristics of equipment malfunctions and maintenance unit's capability. In this research, we present an analysis model that can be used to determine an optimal M/F inventory level based on queuing and absorbed Markov chain theories. And, we applied the new analysis model to come out with an optimal volume of K-1 tank M/F for the OO division, which serves as counterattack military unit. In our view, this research is valuable because, while using more tractable methodology compared to previous research, we present a new analysis model that can describe decision making process on M/F level more satisfactorily.

• Journal of the Korean Magnetics Society
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• v.5 no.1
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• pp.64-70
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• 1995

The authors have studied crystallographic and magrletic properties of $NdFe_{10.7}TiM_{0.3}(M=B,\;Ti)$ by X-ray diffraction, VSM magnetometer, and Mossbauer spectrometer. The Alloys were prepared by arc-melting under argon atmosphere. The $NdFe_{10.7}TiM_{0.3}$ has pure single phase, whereas the $NdFe_{10.7}Ti_{1.3}$ contains some $\alpha-Fe$, from powder X-ray diffractometry. The $NdFe_{10.7}TiM_{0.3}$ has the $ThMn_{12}$-type tetragonal structure with $a_{0}=8.587\;{\AA}\;and\;c_{0}=4.788\;{\AA}$. The Curie temperature ($T_c$) is $570{\pm}3\;K$ from $M\"{o}ssbauer$ spectroscopy performed at various temperatures ranging from 13 to 770 K. Each spectrum of below $T_c$ was fitted with five subspectra of Fe sites in the structure ($8i_{1},\;8i_{2},\;8j_{1},\;8j_{2}\;and\;8f$). The area fraction of the subspectra at room temperature are 16.4, 8.2, 14.8, 21.3 and 39.3 %, respectively. Magenetic hyperfine fields for the Fe sites decrease in the order, $H_{hf}(8i)>H_{hf}(8j)>H_{hf}(8f)$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1658-1663
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• 2015

To control the indoor humidity, humidifier is installed in an air handling unit. Up to now, foreign product made of glasswool has been widely used as a humidifying element. In this study, a new humidifying element made of cellulose and PET was tested, and the performance was compared with Glasdek element, which is made of glasswool. Mass transfer rates and pressure drops were measured from the element which was installed at the entrance of the suction-type wind tunnel. Results show that, $j_m$ and f factors of the new element are 33%~39% larger and 0%~51% smaller than those of Glasdek. Large water absorption capacity and the smoothness of the new element appear to be responsible for the large $j_m$ and small f factor. The mass transfer effectivenesses ($j_m/f^{1/3}$) of the new element are 36%~63% larger than those of Glasdek.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.413-419
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• 2009

The appropriate dripper position in perlite bag was investigated for tomato production. Drippers were laid at 5(F5), 15cm (F15) away from the stem base or 5cm at first and then moved to 15cm later (M5-15). Roots were developed more near the stem base in F5, while less in F15. Roots were distributed evenly in M5-15. In vertical distribution of water in perlite bag, water content was higher as it went deeper with the variation by dripper positions. Yield was high in F15 and low in F5. In conclusion the position of dripper is the best at 15cm from the stem base in perlite bag culture in view of root distribution and yield.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.420-427
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• 2018

The orthogonal pair of Saccharomyces cerevisiae tyrosyl-tRNA synthetase (Sc YRS) and a variant of E. coli initiator tRNA, fMam $tRNA_{CUA}$ which recognizes the amber stop codon is an effective tool for site-specific incorporation of unnatural amino acids into the protein in E. coli. To evolve the amber suppression activity of the orthogonal pair, we generated a mutant library of Sc YRS by randomizing two amino acids at 320 and 321 which involve recognition of the first base of anticodon in fMam $tRNA_{CUA}$. Two positive clones are selected from the library screening with chloramphenicol resistance mediated by amber suppression. They showed growth resistance against high concentration of chloramphenicol and their $IC_{50}$ values were approximately 1.7~2.3 fold higher than the wild type YRS. In vivo amber suppression assay reveals that mutant YRS-3 (mYRS-3) clone containing amino acid substitutions of P320A and D321A showed 6.5-fold higher activity of amber suppression compared with the wild type. In addition, in vitro aminoacylation kinetics of mYRS-3 also showed approximately 7-fold higher activity than the wild type, and the enhancement was mainly due to the increase of tRNA binding affinity. These results demonstrate that optimization of anticodon recognition by engineered aminoacyl tRNA synthetase improves the efficiency of unnatural amino acid incorporation in response to nonsense codon.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.24 no.1
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• pp.25-35
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• 2011

Objective : The present study was designed to assess the potential inhibitory activity of an ethanol extract of Belamcandae Rhizoma (EBR) on the alpha-melanocyte stimulating hormone (${\alpha}$-MSH)-induced melanogenesis signal pathway in B16F10 melanoma cells. Methods : Several experiments were performed in B16F10 melanoma cells. We studied tyrosinase activity, melanin content, cell-free tyrosinase activity and DOPA stain, and performed Western blots and RT-PCR for proteins and mRNA involved in melanogenesis. Results : ${\alpha}$-MSH-induced tyrosinase activity and melanin content were inhibited significantly by EBR. EBR markedly suppressed the protein expression level of tyrosinase in B16F10 melanoma cells. On the other hand, the expression of tyrosinase-related protein-1 (TRP-1) and -2 (TRP-2; DCT) were not affected by EBR. To elucidate the mechanism of the depigmenting property of EBR, we examined the involvement EBR in cAMP response element binding (CREB) protein phosphorylation and microphthalmia-associated transcription factor (MITF) signalling induced by ${\alpha}$-MSH. EBR did not regulate CREB phosphorylation and MITF expression by ${\alpha}$-MSH. Nevertheless, the mRNA expression of tyrosinase was significantly attenuated by EBR treatment without changes in the expression of TRP-1 and -2 mRNA. Conclusion : Our study suggested that EBR inhibits ${\alpha}$-MSH-induced melanogenesis by suppressing tyrosinase mRNA.

• Korean Journal of Plant Resources
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• v.14 no.2
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• pp.152-156
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• 2001

This study was conducted to investigate the flower organ removal effect on Atractylodes macrocephala Koidz which was introduced from China. The results were summarized as follows; The plant height of Flower Organ Cutting(F.O.N.C.) treatment short by 1.7∼2.5 cm compared to Flower Organ Non-Cutting(F.O.N.C.) treatment. But number of stem and stem diameter of F.0.C treatment were similar to that of F.O.N.C. treatment. The fresh weight of above-ground part of F.O.N.C. treatment was decreased 48∼60% compare to F.O.C. treatments. The later was period of F.O.C., the higher was fresh weight of above-ground part. The growth of underground part was more F.O.C. at July 15 and Aug. 20 treatments than F.O.N.D treatment. The dry rhizome yield of F.O.C. at July 15 treatment was increased 40% compare to F.O.N.D treatment. Essential oil content of F.O.C. at July 15 treatment was increased 12% compare to F.O.N.D treatment.

• The Korean Journal of Nuclear Medicine
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• v.38 no.1
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• pp.99-108
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• 2004

Purpose: The ability to noninvasively track the migration of neural progenitor cells would have significant clinical and research implications. We generated stably transfected F3 human neural progenitor cells with human sodium/iodide symporter (hNIS) for noninvasively tracking F3. In this study, the expression patterns of hNIS gene in F3-NIS were examined according to the cultured time and the epigenetic modulation. Materials and Methods: F3 human neural stem cells had been obtained from Dr. Seung U. Kim (Ajou University, Suwon, Korea). hNIS and hygromycin resistance gene were linked with IRES (Internal Ribosome Entry Site) under control of CMV promoter. This construct was transfected to F3 with Liposome. To investigate the restoration of hNIS gene expression in F3-NIS, cells were treated with demethylating agent (5-Azacytidine) and Histone deacetylase inhibitor (Trichostatin A: TSA). The expression of hNIS was measured by I-125 uptake assay and RT-PCR analysis. Results: The iodide uptake of the F3-NIS was higher 12.86 times than F3 cell line. According to the cell passage number, hNIS expression in F3-NIS gradually diminished. After treatment of 5-Azacytidine and TSA with serial doses (up to $20{\mu}M$, up to 62.5nM, respectively) for 24 hours, I-125 uptake and mRNA of hNIS in F3-NIS were increased. Conclusion: These results suggest that hNIS transfected F3 might undergo a change in its biological characters by cell passage. Therefore, the gene ex[ressopm of exogenous gene transferred human stem cell might be affected to the epigenetic modulation such as promoter methylation and Histone deacetylation and to the cell culture conditions.