• Journal of the Korean Wood Science and Technology
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• v.24 no.4
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• pp.22-31
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• 1996

Air permeabilities for both sapwood and heartwood of the three softwoods(Picea jezoensis, Larix gmelini, Pinus sylvestris), imported from the Russian Far East, in the three different structural directions were measured using steady-state rotameter method. After measuring permeability, the liquid absorption into the longitudinal permeability specimens was measured, and then related with the measured permeability. The longitudinal permeability was overwhelmingly greater than the transverse permeability, with the radial direction showing higher permeability than the tangential direction. There appear to be species differences in permeability of the three softwoods. The mean longitudinal sapwood permeability of P. jezoensis(3.300darcy) and P. sylvestris(3.028darcy) were considerably greater(ca. 25times) than that of L. gmelini(0.134darcy). Also the average longitudinal heartwood permeability of P. jezoensis(0.300darcy) was about 10 times as great as that of P. sylvestris(0.029darcy) and L. gmelini(0.024darcy). The average calculated radius of pit openings in the heartwood was $0.101{\mu}m$ for L. gmelini, $0.152{\mu}m$ for P. sylvestris for and $0.703{\mu}m$ for P. jezoensis. Heartwood permeability increases with the increase in radius of pit pore and the decrease in ring width and in extractive content, even though the correlation between permeability and its affecting factors was dependent on species. However, there was an inverse relationship between specific gravity and permeability, showing poor correlation between them. The correlation between air permeability and liquid retention was fairly high, so it was revealed that prediction of liquid absorption into the wood by using permeability was feasible.

• Journal of Plant Biology
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• v.17 no.4
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• pp.31-37
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• 1974

Seedlings of Nongbaek representing strong cold tolerant variety of rice plant, Jinheung of medium variety and Tongil of weak variety were used respectively for the present study. These seedlings were water cultured in phytotron which maintained at the daytime and night temperature of 30-$25^{\circ}C$, 20-2$0^{\circ}C$, 20-15$^{\circ}C$ and 15-1$0^{\circ}C$. The growth rate of plant height, tillering rate, increase in dry weight and absorption pattern of important mineral nutrients at their early growth stage under each temperature conditions were observed. Generally, it appeared that Nongbaek was more active in the growth of plant height than Jinheung, and Jinheung was more active than Tongil under low temperature condition. The tillering rate of these three varieties was equally rapid while it was decreased in the order of weak cold tolerant variety, such as Tongil, Jinheung and Nongbaek as the temperature declined gradually. The dry weigh tincreasing curve showed almost the same pattern in the varieties at the treatment of each temperature. Under low temperature conditions, Nongbaek showed higher absorption rate of N per dry weight and higher absorption amount of per plant body, Jinheung followed and Tongil was the lowest. The absorption amount of P2O5 increased in the top part compared with the roots as temperature rose and decreased as temperature declined. There seemed to be no difference of absorption among the varieties which have different cold tolerance each other. Under low temperature the absorption rate of K per dry weight was high, as a whole, especially Nongbaek was markedly higher than the other two. The absorption rate of Ca, Mg and Fe was also equally high in all varieties under low temperature and Nongbaek showed a more absorptive tendency in the absorption amount under low temperature.

• Journal of the Korean Society of Tobacco Science
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• v.8 no.2
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• pp.29-41
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• 1986

Effects of some mineral nutrients on the chlorine absorption by the plants, on the chemical constituents and physical properties of leaves were investigated tinder the paddy field and pot conditions. The chlorine content of cured leaf grown in paddy field was high in iron and manganese application groups and highest in combined application of iron and manganese. Lime application inhibited the absorption of chlorine and increased the yield and quality of cured leaf, and inhibited the absorption of iron and manganese those causing the grey leaf. Lime application reduced the leaf chlorine content and rate of muddy grey leaf by increasing the soil pH in acid soil.

• Journal of the Optical Society of Korea
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• v.8 no.1
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• pp.1-5
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• 2004

Using the external cavity spectroscopy method, we have observed the saturated absorption spectrum of the P(16) line of the v$_1$+v$_3$ band of $^{13}C$_2$H$_2$$. The frequency of a laser has been stabilized to the saturated absorption spectrum. The relative contrast of the saturation spectrum is about 7% with respect to the linear absorption and the linewidth is about 1.8 MHz. The frequency fluctuation of the stabilized LD is about $\pm$ 20 KHz for a sampling time of 100 ms.

• Bulletin of the Korean Chemical Society
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• v.18 no.12
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• pp.1296-1301
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• 1997

Polymerization of terminal alkynes (phenlacetylene and 4-ethynyltoluene) catalyzed by water soluble rhodium (Ⅰ) complex, RhCl(CO)(TPPTS)2 (TPPTS=m-P(C6H4SO3Na)3) (1) selectively produces cis-transoid polymers at room temperature in homogeneous solution of H2O and MeOH as well as in biphasic solutions of H2O and CHCl3. The rate of polymerization is higher in H2O/MeOH than in H2O/CHCl3. The iridium analog, IrCl(CO)(TPPTS)2 (2) shows catalytic activity for the polymerization of phenylacetylene only at elevated temperature to give trans-polymers. The polymerization rate increases significantly when the trimethylamine N-oxide (Me3NO) was added to the reaction mixtures. The electronic absorption spectra of the cis-transoid polymers show three absorption bands whereas the trasn-polymers show only one absorption band. It seems that the electronic absorption bands depend on the configuration of the polymers.

• Bulletin of the Korean Chemical Society
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• v.13 no.6
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• pp.650-654
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• 1992

Absorption and fluorescence spectra are reported for four different 1 : 3 $Dy^{3+}$ : ligand systems in aqueous solution under mild alkaline pH conditions. The ligands included in this study are oxidiacetate, dipicolinate, iminodiacetate and methyliminodiacetate. The oscillator strengths for the 4f→4f multiplet-to-multiplet transitions are empirically determined from the absorption spectra and the intensity parameters ${\Omega}_{\lambda}$}(${\lambda}$ = 2, 4, 6) for the systems are also obtained by applying the Judd-Ofelt theorem to the observed oscillator strengths. The values of the intensity parameters for the systems are compared and discussed in terms of ligand structural properties to investigate how the intensity parameters can response to the minor changes in the ligand environment. In addition, the relative oscillator strengths for fluorescence are evaluated and compared to the results obtained from absorption spectra.

• Journal of the Korean Wood Science and Technology
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• v.31 no.3
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• pp.17-23
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• 2003

As a fundamental study of developing sawdust board from thinning softwood logs from three species (Pinus densiflora S. et Z., Larix leptolepis G. and Pinus koraiensis S. et Z.), this study examined the effect of board density and resin content on physical and mechanical properties of sawdust board. As the board density increase, thickness swelling, bending strength, and Brinell hardness increased while water absorption decreased. With increasing the resin content, the bending strength and hardness increased while water absorption and thickness swelling decreased. The board made of L. leptolepis was slightly low in its water absorption, and the one made of P. koraiensis was a little high in its bending strength, while there was no definite difference between each kind of trees in their hardness values.

• Journal of Preventive Medicine and Public Health
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• v.17 no.1
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• pp.269-279
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• 1984

The optimum conditions for measuring cadmium content of less than 0.2ppm by flame atomic absorption spectrophotometry were investigated. The cadmium in urine was extracted by APDC-MIBK for the analysis by atomic absorption spectrophotometry after ashing them by a wet method. 1. Optimum conditions by APDC-MIBK and DDTC-MIBK extractions. The acidic aqueous solution was prepared with appropriate amount of 0.IN nitric acid, 5ml of 25% (W/V) sodium potasstum tartarate, 10ml of saturated ammonium sulfate, and 2ml of 2% APDC(or 1 ml of 5% DDTC) chelating agent. The total volume of solution was adjusted to 55 ml and pH to $2{\sim}10$ (or$7{\sim}10$). The aqueous solution was extracted with 10ml MIBK. Concentration of Triton X-100 did not effect the absorbance for APDC-MIBK extraction of cadmium, but absorbance decreased as the concentration increased for DDTC-MIBK extraction. The sensitivity and detection limits for the cadmium determination from APDC-MIBK extraction were 0.0038ppm and 0.0102, 0.0022ppm and 0.0116 for DDTC-MIBK, and 0.0132ppm and 0.0034 for 0.1N nitric acid. APDC-MIBK and DDTC-MIBK extractions were 3 times higher than 0.1N nitric acid for the sensitivity. 2. Excretion of cadmium in 24-hour urine by APDC-MIBK extraction. Determination of cadmium in urine by atomic absorption spectrophotometry of A.A. (Cd=2 mA) mode and B.C. (Cd=4 mA) mode and B.C. (Cd=4mA, $D_2=20mA$) mode showed some difference (p<0.05). The difference of cadmium determination and recovery according to method of standard additions and standard calibration curve method in urine was not significant (p>0.05, $93.48{\pm}11.78%,\;94.83{\pm}22.00%$). Excretion of cadmium in 24-hour urine collection from normal person and variance analysis within measurement variation was not significant (p>0.05), but between interindividual was significant (0.05). Determination of cadmium content by two different methods of flame atomic absorption spectrophotometry and dithizone colorimetry showed that the results from the two methods can be described by a regression line with a good correlation (y=1.0153x-0.2927, x=Cd by D.C., y=Cd by A.A.S., $r=0.8651^*$, p<0.01).

• Journal of Soil and Groundwater Environment
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• v.16 no.6
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• pp.122-132
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• 2011

Mercury accumulates in biota mainly as methylmercury. In nature, methylmercury shows high affinity to organic matter and $CH_3Hg^+$-organic matter complexation affects the mobility and bioavailabiity of methylmercury. In this study, we examined the methylmercury binding sites in an aquatic humic acid as affected by the pH condition using Hg $L_{III}$-edge extended X-ray absorption fine structure (EXAFS). We evaluated methylmercury binding humic ligands using methylmercury-thiol, methylmerury-carboxyl, and methylmercury-amine complexation models. When $CH_3Hg^+$-to-humic reduced sulfur ratio is 0.3, we found that most of $CH_3Hg^+$ binds to thiol ligands at pH 5 and 7. At pH 7, however, some carboxyl or amine ligand contribution is observed, unlike at pH 5 where $CH_3Hg^+$ almost exclusively binds to thiol ligands. The carboxyl or amine ligand contribution may indicate that some types of thiol ligands in the natural organic matter have relatively low complexation constants or acid dissociation constants compared to those of some carboxyl or amine ligands. Analysis results indicate that ~0.2 fraction of methylmercury binds to amine or carboxyl ligands and ~0.8 to thiol ligands at pH 7.

• Journal of Preventive Medicine and Public Health
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• v.7 no.2
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• pp.377-381
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• 1974

Determination of lead in urine is important in industrial hygiene and toxicology. Dithizone method has been principally used for the determination of lead in urine, which gives accurate results in skilful hands but is usually complex and time-consuming. Atomic absorption spectrophotometry is a new simple method and several procedures have been described. However, the influences of pH and the presence of chelating agents during treatment of lead poisoning are not clear. The purpose of this study was to find out the effect of pH and chelating agents on the determination of lead using Shimadzu atomic absorption/flame spectrophotometer, model AA-610. The results obtained were as follows: 1. The atomic absorption spectrophotometry(AAS) could be applied without prior acid digestion to specimens in the absence of chelating agents. The absorbance at $2,170\;{\AA}$, though more sensitive, was more noisy electronically. Therefore, we selected the wavelength of $2,833\;{\AA}$ plus scale expansion. 2. The optimal pH was in the range from 2 to 3. 3. The sensitivity was $0.075{\mu}g/ml/%$ and detection limit was about $0.2{\mu}g/ml$. 4. In the presence of EDTA, lead could not be completely determined without prior acid digestion. 5. On specimens from patients receiving penicillamine therapy, a comparison was made between the values obtained with dithizone method and AAS method with prior acid digestion. The results of comparison showed a very good agreement.