• YAKHAK HOEJI
• /
• v.36 no.3
• /
• pp.220-229
• /
• 1992

The muscarinic acetylcholine receptors of the dog unpregant uterus were characterized using $[^3H]quinuclidinyl$ benzilate(QNB) as a radioligand and the binding of muscarinic receptor agonists and antagonists in the uterus was compared to that in the urinary bladder which contains almost exclusively the M2 receptors in order to determine the receptor subtypes in the uterus. $[^3H]QNB$ binding to uterus and bladder was rapid, saturable and reversible. Scatchard analysis of the saturation data gave linear plots and the Hill coefficients were close to unit, which indicated that each preparation contained a single population of specific binding sites for $[^3H]QNB$. The KD values(120 pM) for QNB were almost identical in both organs, whereas the $B_{max}$ value of 256 fmol/mg protein in the uterus was significantly different from that of 563 fmol/mg protein in the bladder. Muscarinic agonists and antagonists inhibited in a competitive manner the $[^3H]QNB$ binding to the same extent in both organs. The competition binding studies using antagonists(atropine and pirenzepine) exhibited a single binding site and this site had a low affinity for pirenzepine with the Ki value of about 330 nM. However, high and low affinity binding sites were observed with carbachol, methacholine and oxotremorine. These binding studies with agonists and antagonists did not show any differences in drug affinities between uterus and bladder. These results indicate that the muscarinic receptors in the uterus are M2 receptors which have a low affinity for pirenzepine.

• Journal of the Optical Society of Korea
• /
• v.14 no.4
• /
• pp.321-325
• /
• 2010

We analyze the current density - voltage (J - V) curve of a Cu(In,Ga)$Se_2$ (CIGS) thin-film solar cell measured at different irradiation power densities. For the solar-cell sample investigated in this study, the fill factor and power conversion efficiency decreased as the irradiation power density (IPD) increased in the range of 2 to 5 sun. Characteristic parameters of solar cell including the series resistance ($r_s$), the shunt resistance ($r_{sh}$), the photocurrent density ($J_L$), the saturation current density ($J_s$) of an ideal diode, and the coefficient ($C_s$) of the diode current due to electron-hole recombination via ionized traps at the p-n interface are determined from a theoretical fit to the experimental data of the J - V curve using a two-diode model. As IPD increased, both $r_s$ and $r_{sh}$ decreased, but $C_s$ increased.

• Journal of Environmental Science International
• /
• v.9 no.1
• /
• pp.1-11
• /
• 2000

A study on the variational characteristics of water quality and phytoplankton biomass by principal component analysis(PCA) was carried out in Kogum-sudo from February to October in 1993. We analyzed PCA on biological factors such as chlorophyll a and phytoplankton cell numbers for centric and pennate diatoms, phytoflagellates, and total phytoplankton as well as physico-chemical factors as water temperature, salinity, transparency, dissolved oxygen(DO), saturation of DO, apparent oxygen utilization (AOU), chemical oxygen demand(COD), nutrient (ammonia, nitrite, nitrate, phosphate and silicate), N/P ratio and suspended solid(SS). The source of nutrients supply depended on the mineralization of organic matters and inputs of seawater from outside rather than runoff of freshwater. The phytoplankton biomass was changed within short interval period by nutrients change. And it was controlled by the combination of several environmental factors, especially of light intensity, ammonia and phosphate. The marine environmental characteristics were determined by the mineralization of organic matters in winter, by runoff of freshwater including high nutrients concentration in spring, by ammonia uptake and high phytoplankton productivity in summer, and phosphate supplied input seawater from outside of Kogeum-sudo in autumn. And Kogum-sudo was separated with 2 regions by score distributions of PCA. That is to say, one region was middle parts of straits which was characterized by the mixing seawater and the accumulated organic matters, other one region was Pungnam Bay and the water around Kogum Island which was done by high phytoplankyon biomass and productivity year-round.

• BMB Reports
• /
• v.31 no.1
• /
• pp.25-30
• /
• 1998

Kinetic studies of L-Alanine dehydrogenase from Bacillus subtilis-catalyzed reactions in the presence of $Zn^{2+}$ were carried out. The substrate (L-alanine) saturation curve is hyperbolic in the absence of the metal ion but it becomes sigmoidal when $Zn^{2+}$ is added to the reaction mixture indicating the positive cooperative binding of the substrate in the presence of zinc ion. The cooperativity of substrate binding depends on the xinc ion concentration: the Hill coefficients ($n_H$) varied from 1.0 to 1.95 when the zinc ion concentration varied from 0 to $60\;{\mu}m$. The inhibition of AlaDH by $Zn^{2+}$ is reversible and noncompetitive with respect to $NAD^+$ ($K_i\;=\;5.28{\times}10^{-5}\;M$). $Zn^{2+}$ itself binds to AlaDH with positive cooperativity and the cooperativity is independent of substrate concentration. The Hill coefficients of substrate biding in the presence of $Zn^{2+}$ are not affected by the enzyme concentration indicating that $Zn^{2+}$ binding does not change the polymerization-depolymerization equilibria of the enzyme. Among other metal ions, $Zn^{2+}$ appears to be a specific reversible inhibitor inducing conformational change through the intersubunit interaction. These results indicate that $Zn^{2+}$ is an allosteric competitive inhibitor and substrate being a non-cooperative per se, excludes the $Zn^{2+}$ from its binding site and thus exhibits positive cooperativity. The allosteric mechanism of AlaDh from Bacillus subtilis is consistent with both MWC and Koshland's allosteric model.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.471.2-471.2
• /
• 2014

We demonstrate here that an improvement in precursor film density (green density) leads to a great enhancement in the photovoltaic performance of CuInSe2 (CISe) thin film solar cells fabricated with Cu-In nanoparticle precursor films via chemical solution deposition. A cold-isostatic pressing (CIP) technique was applied to uniformly compress the precursor film over the entire surface (measuring 3~4 cm2) and was found to increase its relative density (particle packing density) by ca. 20%, which resulted in an appreciable improvement in the microstructural features of the sintered CISe film in terms of lower porosity, reduced grain boundaries, and a more uniform surface morphology. The low-bandgap (Eg=1.0 eV) CISe PV devices with the CIP-treated film exhibited greatly enhanced open-circuit voltage (VOC, from 0.265 V to 0.413 V) and fill factor (FF, from 0.34 to 0.55), as compared to the control devices. As a consequence, an almost 3-fold increase in the average power conversion efficiency, 3.0 to 8.2% (with the highest value of 9.02%), was realized without an anti-reflection coating. A diode analysis revealed that the enhanced VOC and FF were essentially attributed to the reduced reverse saturation current density (j0) and diode ideality factor (n). This is associated with the suppressed recombination, likely due to the reduction in recombination sites such as grain/air surfaces (pores), inter-granular interfaces, and defective CISe/CdS junctions in the CIP-treated device. From the temperature dependences of VOC, it was confirmed that the CIP-treated devices suffer less from interface recombination.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.30 no.1
• /
• pp.38-49
• /
• 1988

This paper presented as follows results of laboratory model tests with various shaped footings on soil bed reinforced with the strips on the base of behaviour of soil structure according to the loads and triaxial test results reinforced with geotextiles. Their parameters studied were the effects on the bearing capacity of a footing of the first layer of reinforcement, horizontal and vertical spacing of layers, number of layers, tensile strength of reinforcement and iclination load to the vertical 1.Depending on the strip arrangement, ultimate bearing capacity values could be more improved than urreinforced soil and the failure of soil was that the soil structure was transfered from the macrospace to microspase and its arrangement, from edge to edge to face to face. 2.The reinforcement was produced the reinforcing effects due to controlling the value of factor of one and permeable reinforcement was never a barrier of drainage condition. 3.Strength ratio was decreased as a linear shape according to increment of saturation degree of soil used even though at the lower strength ratio, the value of M-factor was rot influenced on the strength ratio but impermeable reinforcement decreased the strength of bearing capacity. 4.Ultimate bearing capacity under the plane-strain condition was appeared a little larger than triaxial or the other theoretical formulars and the circular footing more effective. 5.The maximum reinforcing effects were obtained at U I B=o.5, B / B=3 and N=3, when over that limit only acting as a anchor, and same strength of fabric appeared larger reinforcing effects compared to the thinner one. 6.As the LDR increased, more and more BCR occurred and there was appeared a block action below Z / B=O.5, but over the value, decrement of BCR was shown linear relation, and no effects above one. 7.The coefficient of the inclination was shown of minimum at the three layers of fabrics, but the value of H / B related to the ultimate load was decreased as increment of inclination degree, even though over the value of 4.5 there wasn't expected to the reinforcing effects As a consequence of the effects on load inclination, the degree of inclination of 15 per cent was decreased the bearing capacity of 70 per cent but irnproved the effects of 45 per cent through the insertion of geotextile.

• Journal of the Korean Magnetics Society
• /
• v.15 no.1
• /
• pp.12-16
• /
• 2005

The $Fe_{87}Zr_{7}B_{6}$ amorphous alloy after neutron irradiation are studied hysteresis loop and complex permeability measurements. The total integration fluence of fast neutrons is varied from $1.92{\times}10^{14}$ to $4.85{\times}10^{16}n_{f1}cm^{-2}$. After neutron irradiation, the imaginary part of complex permeability in low frequency region decreased due to the decrease of wall motion, but the permeability in high frequency region increased due to the enhancement of rotational magnetization. The measurement of hysteresis loop showed the increase of magnetic softness, related to rotational magnetization, but saturation magnetization was decreased in neutron irradiation sample.

• Transactions of Materials Processing
• /
• v.8 no.3
• /
• pp.247-247
• /
• 1999

The segregation (distribution) of nickel and the composition of its constituents influence the low thermal expansion characteristics (Invar effect) in Fe-30 wt.% Ni-12.5 wt.% Co-xC Invar alloy. The change of coefficient of the thermal expansion and magnetic properties were studied as an aspect of carbon addition causing the segregation of Ni in primary austenite of as-cast Fe-30 wt.% Ni-12.5 wt.% Co Invar alloy. The coefficient of thermal expansion of Fe-30 wt.% Ni-12.5 wt.% Co-xC Invar alloy showed its lowest value at 0.08 wt.% carbon, increased with increasing carbon content in the range of 0.08-1.0 wt.%C, kept constant at 1.0-2.0 wt.%C and decreased at carbon higher than 2.0 wt.%. The effective distribution of the coefficient of nickel in as-cast Fe-30 wt.% Ni-12.5 wt.% Co-xC Invar alloy increased with increasing carbon content. The volume fraction of they phase of Fe-30 wt.% Ni-12.5 wt.% Co-xC alloy increased with increasing carbon content. The microstructure of Fe-30 wt.% Ni-12.5 wt.% Co-xC alloy changed with the carbon content was independent of the coefficient of thermal expansion. The Curie temperature changed linearly with the carbon content and was similar to the change of the coefficient of thermal expansion. Moreover, the coefficient of thermal expansion decreased when the ratio of saturation magnetization to Curie temperature ($\sigma_s/T_c$) increased, decreasing the Curie temperature and showed a specific relationship with the magnetic properties of the Fe-30 wt.% Ni-12.5 wt.% Co-xCInvar alloy.

• Journal of Welding and Joining
• /
• v.2 no.1
• /
• pp.30-40
• /
• 1984

Moisture content in the coating of an electrode is known to cause defects such as porosities, fish eyes and cracks in the weld metal, however, quantitative relationship between them is not clearly understood. In this study widely consumed and the most common type of arc welding rods such as ilmenite and low hydrogen type were chosen for the investigation, and attempts were made to correlate the relationship between the mechanical properties and gas contents when welding was carried out with electrodes of various moisture contents. As the relative humidity changed from 70% to 92%, it was determined that moisture content to reach saturation was in the range of 0.6~6.8%. As the moisture content in the electrode coating was increased, the amount of gaseous components (H, O, N) in the weld metal was accordingly increased, especially diffusible hydrogen showed prominent effect, i.e. it increased proportionally to the increase of the moisture content. The mechanical properties of the weld metal was observed to become more inferior as the diffusible hydrogen was greater. It was determined for ilmenite type of electrode that the increase of hydrogen content was approximately 1.8ml per unit weight percent increase of moisture and also tensile strength resulted lowering from $45.3kg/\textrm{mm}^2$ to $42.7kg/\textrm{mm}^2$ as moisture content increased from 0.7% to 6.8%. For low hydrogen type the increase of the hyrogen was about 2.4ml per unit percent of moisture and tensile strength decreased from $63.0kg/\textrm{mm}^2$ to $53.8kg/\textrm{mm}^2$ particularly in the region of moisture content 0.1~4.2%.

• Progress in Superconductivity and Cryogenics
• /
• v.17 no.1
• /
• pp.21-24
• /
• 2015

New results of dependence of magnetic field, trapped by a stack of HTS tapes, on amount of tapes in a stack are reported. Commercial GdBCO tape 12 mm width and without Cu layer was used for the research. Tape was divided in square pieces $12{\times}12mm^2$ from which stacks were formed. Filling factor of the tape was about 1.4%. Measurements were carried out for stacks with height from 5 to 250 pieces and at wide temperature range from liquid helium to liquid nitrogen. Both FC (field cooling) and ZFC (zero field cooling) cooling methods were used in the research. These two methods show matching results with good accuracy. As a result dependences of trapped magnetic flux on amount of tapes for different temperatures were received. Research shows, that with increasing height of the stack trapped magnetic field value reach saturation at about 60 tapes in a stack for low temperatures. From 60 to 100 tapes increase of magnet flux is only 5%. Thus increase amount of tapes in a stack is not profitable. Also investigation of trapped magnet field relaxation was carried out. Relaxation speed decreases with increasing amount of elements. It means that the higher the stack is, the longer trapped flux will be held in cause of the same temperature.