• The Journal of the Acoustical Society of Korea
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• v.25 no.1E
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• pp.14-19
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• 2006

Ultrasonic absorption and velocity spectra in bovine serum albumin (BSA) aqueous solutions have been measured at $20^{\circ}C$ over the frequency range 0.2-3 MHz in the pH range 1.5-13.2. The high-Q ultrasonic resonator and pulse-echo overlap methods were used. At acid pH's, excess absorption over that of pH 7 was explained by double relaxation. The pH dependences of the relaxation frequency and maximum absorption per wavelength, showed that the relaxation at about 200 kHz was related to the expansion of molecules and that about 3 MHz resulted from the proton transfer reaction of carboxyl group. At alkaline pH's, the excess absorption was explained by double relaxation. The relaxation at about 300 kHz was associated with a helix-coil transition, and that about 3 MHz was attributed to the proton transfer reaction of phenolic group. The rate constants and volume changes associated with these processes were estimated.

• The Korean Journal of Ecology
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• v.6 no.4
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• pp.243-249
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• 1983

Absorption pattern of potassium, calcium, phosphate and nitrate ions, and the pH change during ion-absorption at pH 3.0-11.0 by Oryza sativa L. were studied to investigate indirectly the evidence of H^+-efflux by ATPase. The rice seedlings which were grown either in $L^{\circ} -dark or in L^+-sunlight$, were used both in each ion-absorption to compare with one another. The uptake rate of these ions appeared to favor more in $L^+than in L^{\circ}$, over all range in pH, nearly with the same pattern. The absorption of potassium resulted in bell shape and that of calcium increased linearly to the alkali range. The shape of phosphate-absorption showed nearly the t-distribution curve with high value in acid range and the uptake of nitrate resulted in the dual peaks, but higher in acid range. The pH of the external solution changed from the range of 3.5-11.0 to 3.5-7.0 after lhr-absorptioin, and further acidified after 3hr-absorption. It is suggested that the pH change of the external solution be affected by $ H^+-efflux$ which may be caused by the ATP-hydrolysis.

• Preventive Nutrition and Food Science
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• v.8 no.1
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• pp.1-6
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• 2003

Catechins exhibit a hypocholesterolemic effect in cholesterol-fed animals. The present study was conducted to examine whether (+)-catechin influences the absorption of cholesterol in rats. Male Sprague-Dawley rats were fed ad libitum an AIN-93G diet containing soybean oil for 5 wk. Rats with lymph cannulae were infused at 3.0 mL/h for 8 h via a duodenal catheter with a lipid emulsion containing radiolabeled cholesterol with or without (+)-catechin. Lymph was collected hourly for 8 h. The enteral infusion of (+)-catechin significantly lowered the lymphatic absorption of $^{14}$ C-cholesterol (21.1 $\pm$ 3.6% dose/B h) compared with controls infused with the lipid emulsion devoid of (+)-catechin (38.2 $\pm$ 1.2% dose/8 h). The intestinal absorption of $\alpha$-tocopherol (24.2$\pm$3.0% dose/8 h) also was significantly decreased by (+)-catechin infusion, relative to controls (32.2$\pm$2.2% dose/8 h). However, the lymphatic outputs of oleic acid and phospholipid were not affected by enteral (+)-catechin infusion. The results indicate that (+)-catechin has a profound inhibitory effect on the intestinal absorption of cholesterol and $\alpha$-tocopherol without affecting the absorption of fat.

• Journal of the Korean Solar Energy Society
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• v.23 no.4
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• pp.37-43
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• 2003

The aim of this research is to study the feasibility of the solar(hot fluid) driven $NH_3/H_2O$ absorption chiller, made by re-manufacturing of Gas fired $NH_3/H_2O$ absorption chiller. This experimental study is performed with the temperature of the inlet hot fluid of generator. In order to determine the inlet temperature of the generator, which gives maximum COP, the experimental data are obtained with various hot fluid supply temperature in range of $130\sim170^{\circ}C$. Remodeled chiller is operated with periodical cooling effect, which due to mixture subcooled pool boiling, then the COP is evaluated in average. The maximum COP$(\sim0.36)$ is at $160^{\circ}C$. The temperature is stable operation temperature range of typical vacuum collector. It offers a feasibility of solar driven $NH_3/H_2O$ absorption chiller.

• 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.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.792-799
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• 1998

Further improvement of existing $H_{2}O/LiBr$ absorption refrigeration machine is absolutely neces-sary to promote the utilization of gas-cooling system Among various methods to improve the per-formance of the absorption refrigeration machine this research has focused on the use of a new working fluid that has better properties than the existing $H_{2}O/LiBr$ working fluid. In the series of the research, $H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$ system was selected as the most promisable candidate. The absorption refrigeration machine is water-cooled double-effect, $H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$ sys-tem with series flow type. In this study we found out the characteristic of new working solution through the cycle simulation and compared the result with that of LiBr solution to evaluate. Theoptimum designs and operating conditions were determined based on the operating constraints and the coefficient of performance. Results demonstrate that new working fluid subsrantially increases COP by as much as 10% and has a wider working range with 8% higher crystallization limits compared to the conventional $H_{2}O/LiBr$.

• Journal of the Korean Institute of Gas
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• v.2 no.4
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• pp.47-52
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• 1998

Water vapor absorption performance of four components solution ($LiBr+LiNO_3+LiC1+H_2O$) which could be substituted for commonly used $LiBr/H_2O$ solution in water cooled abosorption chiller is tested using a vertical tube absorber. Inlet solution concentration, inlet solution temperature, solution flow rate and inlet temperature of cooling water is varied as experimental parameters. The results of the experiment of water vapor absorption performance show that four components solution should have $2\%$ higher concentration for equal absorption capacity of $LiBr/H_2O$. But considering that four components solution have higher solubility than LiBr solution about $3\%$ high oncentration, four components solution ($LiBr+LiNO_3+LiC1+H_2O$) have more absorption capacity than LiBr solution in actual absorption chiller and can be applied to a small or air cooled absorption chiller.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.124-129
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• 2008

The objectives of this paper are to examine the effect of nano-particles on the pool type absorption heat transfer enhancement and to find the optimal conditions to design a highly effective compact absorber for $NH_3/H_2O$ absorption system. The effect of $Al_2O_3$ and CNT particles on the absorption performance is studied experimentally. The experimental ranges of the key parameters are 20% of $NH_3$ concentration, $0{\sim}0.08%$ (volume fraction) of CNT particles, and $0{\sim}0.06%$ (volume fraction) of $Al_2O_3$ nano-particles. For the $NH_3/H_2O$ nanofluids, the heat transfer rate and absorption rate with 0.02 vol% $Al_2O_3$ nano-particles were found to be 28.9% and 17.8% higher than those without nano-particles, respectively. It is recommended that the concentration of 0.02 vol% of $Al_2O_3$ nano-particles be the best candidate for $NH_3/H_2O$ absorption performance enhancement.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.782-791
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• 1998

This paper presents a computer simulation of five types of triple effect absorption cycles employ-ing the refrigerant absorbent combinations of NH3/LiNO3 low-pressure type NH3/LiNO3+H2O/LiBr binary two-stage type series flow cycle and two types of parallel flow cycle for H2O/LiBr. The absorption systems is investigated through cycle simulation to obtain the system characteristics with the cooling water inlet temperature approach temperature of absorber loss temperature of absorber and chilled water outlet temperature. The most important characteristic temperature of absorber and chilled water outlet temperature. The most important characteristic of NH3/LiNO3 low-pressure type and a NH3/LINO3+H2O/LiBr binary two-stage type is that it obtains a coefficient of performance higher than the sum of the performance coefficients of its part operating independently. As a result of this analysis the optimum designs and operating conditions were determined based on the operating conditions and the coefficient of performance.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.2
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• pp.80-85
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• 2006

The foliar injuries and absorption rates of calcium compounds in tomato (Lycopersicon esculentum cv. momotaro) and citrus [Shiranuhi(C. Marc. ${\time}C$. sinensis Osbeck)${\time}C$. reticulata Blanco)] were investigated. 0.3, 0.5 and 1.0% of $CaCl_2$, $Ca(NO_3)_2$, $Ca(H_2PO_4)_2$, Ca-EDTA, Ca formate or Ca acetate solution were applied to the leaves of tomato and citrus. The leaf burns were observed only in the foliar applications of Ca-EDTA and $Ca(H_2PO_4)_2$. Ca-EDTA exhibited more serious foliar injury than CaH2PO4. As applied with $^{45}CaCl_2$, $^{45}Ca(NO_3)_2$, $^{45}Ca$ formate or $^{45}Ca$ acetate, the rates of Ca absorptions by tomato and citrus leaves for 7 days were 17 to 32% and 6.6 to 46%, respectively. It meant that the absorption was differently influenced on calcium compounds. In tomato, the order of Ca foliar absorption was $Ca(NO_3)_2$ > Ca formate = $CaCl_2$ > Ca acetate. Although there was no difference in Ca absorption between the adaxial and abaxial parts of tomato leaves, total absorption was greater in expanded leaves than in expanding ones. On the other hand, in citrus Ca foliar absorption from $Ca(NO_3)_2$ or Ca formate was more active than that from $CaCl_2$ or Ca acetate. In conclusion, $Ca(NO_3)_2$ and Ca formate are recommended for the foliar application of Ca in tomato and citrus in order to increase absorption of Ca into their leaves.