• BMB Reports
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• v.34 no.3
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• pp.194-200
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• 2001

Secreted arginase from Evernia prunastri thallus has been purified 616-fold from the incubation medium. Purified arginase was resolved as only one peak in a capillary electrophoresis with a pI value of 5.35. The protein contained high amounts of acidic amino acids, such as Asx and Glx, and a relatively high quantity of Ser and Gly. The molecular mass of native, purified arginase was estimated as about 26 kDa by SE-HPLC. Substrate saturated kinetic showed a typical Michaelis-Menten relationship with a K_m value of 3.3 mM L-arginine. Atranorin behaved as a mixed activator of the enzyme (apparent $K_m$ = 0.96 mM); whereas evernic and usnic acid were revealed as non competitive inhibitors (apparent $K_m$ values were 3.16 mM and 3.05 mM, respectively). Kinetics of atranorin binding indicated that saturation was reached from 0.18 ${\mu}mol$ of the total atranorin and the occurrence of multiple sites for the ligand. This agrees with a possible aggregation of several enzyme subunits during the interaction process. A value of binding sites of about 12 was obtained. The binding of evernic acid was saturated from 23 nmol of total phenol. The number of binding sites was about 5. The loss of the binding ability of evernic acid could be interpreted as a single negative cooperatively. Usnic acid behaves in a similar way to evernic acid, although the binding saturation occurs at $0.14\;{\mu}moles$ of the ligand. This binding appears to be unspecific, and has 28 usnic acid binding sites to the protein.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.250-253
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• 2007

An evaporated Ti/Pd/Ag contact system is most widely used to make high-efficiency silicon solar cells, however, the system is not cost effective due to expensive materials and vacuum techniques. Commercial solar cells with screen-printed contacts formed by using Ag paste suffer from a low fill factor and a high shading loss because of high contact resistance and low aspect ratio. Low-cost Ni and Cu metal contacts have been formed by using electroless plating and electroplating techniques to replace the Ti/Pd/Ag and screen-printed Ag contacts. Ni/Cu alloy is plated on a silicon substrate by electro-deposition of the alloy from an acetate electrolyte solution, and nickel-silicide formation at the interface between the silicon and the nickel enhances stability and reduces the contact resistance. It was, therefore, found that nickel-silicide was suitable for high-efficiency solar cell applications. The Ni contact was formed on the front grid pattern by electroless plating followed by anneal ing at $380{\sim}400^{\circ}C$ for $15{\sim}30$ min at $N_{2}$ gas to allow formation of a nickel-silicide in a tube furnace or a rapid thermal processing(RTP) chamber because nickel is transformed to NiSi at $380{\sim}400^{\circ}C$. The Ni plating solution is composed of a mixture of $NiCl_{2}$ as a main nickel source. Cu was electroplated on the Ni layer by using a light induced plating method. The Cu electroplating solution was made up of a commercially available acid sulfate bath and additives to reduce the stress of the copper layer. The Ni/Cu contact was found to be well suited for high-efficiency solar cells and was successfully formed by using electroless plating and electroplating, which are more cost effective than vacuum evaporation. In this paper, we investigated low-cost Ni/Cu contact formation by electroless and electroplating for crystalline silicon solar cells.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.319-319
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• 2013

Even though the fabrication methods of metal oxide based thin film capacitor have been well established such as RF sputtering, Sol-gel, metal organic chemical vapor deposition (MOCVD), ion beam assisted deposition (IBAD) and pulsed laser deposition (PLD), an applicable capacitor of printed circuit board (PCB) has not realized yet by these methods. Barium Strontium Titanate (BST) and other high-k ceramic oxides are important materials used in integrated passive devices, multi-chip modules (MCM), high-density interconnect, and chip-scale packaging. Thin film multi-layer technology is strongly demanded for having high capacitance (120 nF/$mm^2$). In this study, we suggest novel multi-layer thin film capacitor design and fabrication technology utilized by plasma assisted deposition and photolithography processes. Ba0.6Sr0.4TiO3 (BST) was used for the dielectric material since it has high dielectric constant and low dielectric loss. 5-layered BST and Pt thin films with multi-layer sandwich structures were formed on Pt/Ti/$SiO_2$/Si substrate by RF-magnetron sputtering and DC-sputtering. Pt electrodes and BST layers were patterned to reveal internal electrodes by photolithography. SiO2 passivation layer was deposited by plasma-enhanced chemical vapor deposition (PE-CVD). The passivation layer plays an important role to prevent short connection between the electrodes. It was patterned to create holes for the connection between internal electrodes and external electrodes by reactive-ion etching (RIE). External contact pads were formed by Pt electrodes. The microstructure and dielectric characteristics of the capacitors were investigated by scanning electron microscopy (SEM) and impedance analyzer, respectively. In conclusion, the 0402 sized thin film multi-layer capacitors have been demonstrated, which have capacitance of 10 nF. They are expected to be used for decoupling purpose and have been fabricated with high yield.

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.656-662
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• 1998

To make a distinction between the influence of the dielectric constant and of methanol concentration on trypsin-catalyzed hydrolysis and methanolysis at $0^{\circ}C$, a model reaction of $N^u$-benzyloxycarbonyl-L-lysine p-nitrophenyl ester with water-methanol mixtures was chosen and a kinetic study done. The $k_{cat}$ values increased with methanol concentration, in a linear manner whereas $K_{M}$ values increased in a log-linear fashion. However, the $k_{cat},$_{M}$ ratio increased at lower methanol concentrations than 30% and then began to decrease at higher concentrations. The decrease in $k_{catK_M}$observed at higher than 30% methanol concentrations is attributed to the hydrophobic partitioning effect on substrate binding. On the other hand, the increase in $k_{catK_M}$ in the 0~30% methanol concentration range seems to be due to the effect of nucleophilic cosolvent on $k_{cat}$ and of the dielectric constant on $k_m$. This explanation was verified by measuring the effect of varying the dielectric constant of the medium on kinetic constants with isopropyl alcohol chemically unrelated to the enzyme reaction as the methanol concentration is maintained at a constant level. Therefore, we conclude that the effect of increasing the methanol concentration in the model reaction on the kinetic parameters $k_{cat \;and\;{K_M}}$ is caused by changes in both the nucleophilicity and the dielectric constant of the medium. Based on product analysis, the increase in $k_4, k_3$by decreasing the temperature can be accounted for by the suppression of hydrolytic reactions. This observation indicates that the nucleophile is favored by low temperatures. There was no loss of trypsin activity over a 10 h period in 60% methanol concentration at $pH^＊\; 5.5,\; 0^{\circ}C$.EX>.

• The Korean Journal of Pharmacology
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• v.30 no.1
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• pp.59-65
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• 1994

The experiments were performed to determine whether lidocaine interferes with the utilization of lipid as source of energy fuel for the contractile process by the isolated rat atria. Rats were starved for two days in order to inerease the lipid content of the heart. Atria from starved rats were better able to maintain their contractility in the absence of exgenous substrate, and also were more resistant to depression by lidocaine than atria from fed rats. Starvation results in a marked loss of body weight in rats. In contrast to the starved rats, the body weight of fed rats inereased with time. The smaller reduction in contractile activity of atria from the starved rats may suggest that endogenous lipid accumulates during starvation period and is used as an energy source for the contractile process in the face of a lidocaine-induced blockade in glycolysis.

• Journal of Microbiology and Biotechnology
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• v.25 no.11
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• pp.1827-1834
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• 2015

The SMG1 lipase from Malassezia globosa is a newly found mono- and diacylglycerol (DAG) lipase that has a unique lid in the loop conformation that differs from the common alpha-helix lid. In the present study, we characterized the contribution of three residues, L103 and F104 in the lid and F278 in the rim of the binding site groove, on the function of SMG1 lipase. Site-directed mutagenesis was conducted at these sites, and each of the mutants was expressed in the yeast Pichia pastoris, purified, and characterized for their activity toward DAG and p-nitrophenol (pNP) ester. Compared with wild-type SMG1, F278A retained approximately 78% of its activity toward DAG, but only 11% activity toward pNP octanoate (pNP-C8). L103G increased its activity on pNP-C8 by approximately 2-fold, whereas F104G showed an approximate 40% decrease in pNP-C8 activity, and they both showed decreased activity on the DAG emulsion. The deletion of 103-104 retained approximately 30% of its activity toward the DAG emulsion, with an almost complete loss of pNP-C8 activity. The deletion of 103-104 showed a weaker penetration ability to a soybean phosphocholine monolayer than wild-type SMG1. Based on the modulation of the specificity and activity observed, a pNP-C8 binding model for the ester (pNP-C8, N102, and F278 form a flexible bridge) and a specific lipid-anchoring mechanism for DAG (L103 and F104 serve as "anchors" to the lipid interface) were proposed.

• Journal of Microbiology and Biotechnology
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• v.24 no.9
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• pp.1196-1206
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• 2014

A metagenomic fosmid library was constructed using genomic DNA isolated from the gut microflora of Hermetia illucens, a black soldier fly. A cellulase-positive clone, with the CS10 gene, was identified by extensive Congo-red overlay screenings for cellulase activity from the fosmid library of 92,000 clones. The CS10 gene was composed of a 996 bp DNA sequence encoding the mature protein of 331 amino acids. The deduced amino acids of CS10 showed 72% sequence identity with the glycosyl hydrolase family 5 gene of Dysgonomonas mossii, displaying no significant sequence homology to already known cellulases. The purified CS10 protein presented a single band of cellulase activity with a molecular mass of approximately 40 kDa on the SDS-PAGE gel and zymogram. The purified CS10 protein exhibited optimal activity at $50^{\circ}C$ and pH 7.0, and the thermostability and pH stability of CS10 were preserved at the ranges of $20{\sim}50^{\circ}C$ and pH 4.0~10.0. CS10 exhibited little loss of cellulase activity against various chemical reagents such as 10% polar organic solvents, 1% non-ionic detergents, and 0.5 M denaturing agents. Moreover, the substrate specificity and the product patterns by thin-layer chromatography suggested that CS10 is an endo-${\beta}$-1,4-glucanase. From these biochemical properties of CS10, it is expected that the enzyme has the potential for application in industrial processes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.307-315
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• 2005

We have studied to obtain the SAW filter for the passband was formed on the Langasite substrate and was evaporated by Aluminum-Copper alloy and then we performed computer-simulated by simulator. We can fabricate that the block weighted type IDT as an input transducer of the filter and the withdrawal weighted type IDT as an output transducer of the filter from the results of our computer-simulation. Also, we have performed to obtain the properly design conditions about phase shift of the SAW filter for WCDMA. We have employed that the number of pairs of the input and output IDT are 50 pairs and the thickness and the width of reflector are 5000$\AA$ and 3.6$mu$m, respectively. Frequency response of the fabricated SAW filter has the property that the center frequency is about 190MHz and bandwidth at the 3dB is probably 8.2MHz. And we could obtain that return loss is less then 16dB, ripple characteristics is probably 4dB and triple transit echo is less then 18dB after when we have matched impedance.

• Journal of Navigation and Port Research
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• v.27 no.5
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• pp.505-511
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• 2003

In this paper, a driving amplifier stage with 1 Watt output has been designed and fabricated, which is operating at UHF band( 470 ∼ 806 MHz) for digital TV repeater. In the driving amplifier stage, preamplifier and 1 Watt unit amplifier are integrated by one electric substrate which is 2.53 in dielectric constant and 0.8 mm thickness. When the driving amplifier stage is flown by bias voltage of 28 V DC and current of 900 mA. it has the gain of more than 53.5 dB. the gain flatness of $\pm$0.5 dB and return loss of less than -15 dB in 470 ∼ 806 MHz. Also, when two signals at 2 MHz frequency interval are input port into the driving amplifier stage with 1 Watt output, it resulted in excellent characteristics to designed specification with showing intermodulation distortion characteristics of more than 48 dBc.

• Journal of Advanced Navigation Technology
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• v.12 no.2
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• pp.122-131
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• 2008

In this paper, an S-band oscillator of the low phase noise property using miniaturized microstrip hairpin shaped ring resonator has been designed and implemented. The TACONIC's RF-35 substrate has a dielectric constant ${\varepsilon}_r$=3.5 a thickness h=20mil a copper thickness t=17 um and loss tangent $tan{\delta}$=0.0025. The designed and implemented 2.45 GHz oscillator shows low phase performance of -100.5 dBc/Hz a 100kHz offset. Output power 20.9 dBm at center frequency 2.45 GHz and harmonic suppression -32 dBc. The circuit was implemented with hybrid technique. But can be fully compatible with the RFIC's, MIC and MMIC due to its entirely planar structure.