• Analytical Science and Technology
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• v.9 no.3
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• pp.279-291
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• 1996

The new chelating resins, XAD-2, 4, 16-TAC and XAD-2, 4, 16-TAO were synthesized by Amberlite XAD-2, XAD-4, and XAD-16 macroreticular resins with 2-(2-thiazolylazo)-p-cresol(TAC) and 4-(2-thiazolylazo)orcinol(TAO) as functional groups and were characterized by elemental analysis and FT-IR spectrometry. It was found that the content of functional group in chelating resin was 0.60mmol/g in XAD-16-TAC and 0.68mmol/g in XAD-16-TAO respectively. The chelating resins were stable in acidic and alkaline solution and can be reused over 10 times. The sorption behavior of some metalions to two chelating resins was investigated by batch method, which included batch equilibrium, effect of pH, coexisting ions and masking agent. For the optimum condition of sorption, the time required for equilibrium was about 1 hour and optimum pH was 5. In the presence of anions such as ${SO_4}^{2-}$ and $CH_3COO^-$, the sorption of U(VI) ion was slightly reduced but other anions such as $Cl^-$ and $NO{_3}^-$ revealed no interference effect. Also, sorption capacity of U(VI) ion was decreased by addition of $CO{_3}^{2-}$ ion because of complex formation of $[UO_2(CO_3)_3]^{4-}$, but alkali metals and alkali earth metals including Na(I), K(I), Mg(II), and Ca(II) were not affected for the sorption extent. Masking agent, NTA showed better separation efficiency of U(VI) ion from coexisting metal ions such as Th(IV), Zr(IV), Hf(IV), Cu(II), Cd(II), Pb(II), Ni(II), Zn(II) and Mn(II) than EDTA, CDTA.

• Korean Journal of Food Science and Technology
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• v.33 no.4
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• pp.427-436
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• 2001

The effects of storage form (paddy and milled rice) and storage period (1, 2, and 3 years) of rice at low temperature $(4^{\circ}C)$ on physicochemical properties of milled and cooked rice and sensory characteristics of cooked rice were investigated. The proximate compositions except moisture content of rice decreased as the storage period increased. Water binding capacity, solubility and swelling power of rice flour decreased with the extended storage period. In the amylogram, the initial pasting temperature, paste viscosity and breakdown of paddy rice flour slurry decreased after 2 years of storage. Moisture content of cooked rice increased while the amount of water evaporated during cooking decreased. These trends were obvious with the longer storage period. Lightness and yellowness of cooked rice were greatly changed after 3 years of storage, regardless of storage form. Texture profile analysis of cooked rice by Texture Analyzer revealed that hardness, fracturability, gumminess were gradually increased while adhesiveness decreased as the storage period of rice increased. A trained panel found that color intensity, intactness of grains, rancid flavor, rice bran flavor, wet cardboard flavor, hardness and chewiness of cooked rice increased with the longer storage period. However, glossiness, transparency, plumpness, puffed corn flavor, dairy flavor, boiled egg white flavor, sweet taste, adhesiveness to lips, smoothness and inner moisture decreased with the extended storage period up to 3 years. Instrumental hardness was highly correlated with sensory hardness.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.7-24
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• 1977

This paper is the forth and fifth one of the study on balanced type oscillating mole drainer. In the light of the results from previous reports about the model tests, some design criteria were established and a prototype machine was set up for experimental purpose. Motion characteristics and functionof the each parts of the machine were checked and analyzed. After that, performance tests of the prototype machine were carried out in thefield. Obtained results are summarized as follows ; 1. Ten centimeter of the bullet diameter was determined so as to be able to attach it to the tractors with capacity of 30 PS to 40 PS. 2. To maintain the balance between the moments of the front shank and rear shank, the oscillating amplitude of the rear bullet was determined to be larger than that of the front bullet. At the same time , the oscillating direction of the rear bullet was designed with the inclines of ten to thirty degrees. 3. An octagonal dynamo transduced was developed for measuring the compressive force of the upper link is measuring the draft force of the machine. Acceptable linear relationship between forces and strain responses from O.D.T. was obtained. 4. Analysing the balancing mechanism of the acting part of the machine , it was found that the total draft force of the machine was equal to the difference between the sum of the draft force produced from the right and left side bending moments of the lower drawber and the compressive force on the upper link. 5. There are acceptable linear relationship between the strain and twisting moment by driving shaft, and between strain and shank moment. Above results enable us to carry out the field experiment with prototype machine. 6. When the test machine was used in the field, it was possible to reduce the oscillating acceleration by forty percent in average as compared it with the single bullet mole drainer. 7. When the test machine was used under the oscillating condition, the dratt torce was reduced by 27 percent to 59 percent as compared it with the test machine under non-oscillating condition, while the draft force was increased by 7 percent to 20 percent as compared it with the mole drainer having oscillating single bullet. The reasoning behind this fact was considered as the resistance force due to the rear shank and bullet. 8. As the amplitude and frequency of the bullet were increased, the torque was increased accordingly. This tendency could be varied with the various characteristics of the given soils. And the larger frequency and amplitute, the more increasing oscil\ulcornerlating power but decreasing draft brce were needed, and draft force was increased as the velocity was increased.9. When the amplitude of the rear bullet was designed to be larger than that of the front bullet, the minimum value of the moment was lowered and oscillating acceleration was reduced. And when the oscillating direction of the rear bullet was declined back\ulcornerwards, oscillating acceleration was increased along with the increasing angle of decli\ulcornernation. When the test machine was operated in high speed, the difference between maximum moments and minimum ones became narrow. This varying magnitude of moments appeared on the moment oscillogram seems to be correlated to the oscillating acceleration and draft force. 10. From the analysis of variance, it was found that those factors such as frequency, amplitude, and operating velocity significantly affected in the oscillating acceleration, the draft resistance, the torque, the moment, and the total power required. And interaction between frequency and amplitude affected in the oscillating acceleration. 11. Within the given situation of this study, the most preferable operating conditions of the test machine were 7 Hz in oscillating frequency, 0.54 m/sec in operating velocity, and 39.1 mm in oscillating amplitude of front and rear bullets. However, it is necessary to select the proper frequency and magnitude of oscillation depending on the soil properties of the field in which the mole drainer is practiced by use of a bal1nced type oscillating mole drainer. 12. It is recommended that a comparative study of the mole drainers would be performed in the near future using two separate balanced oscillating bullet with the one which is operated by oscillating the movable bullet in a single cylinder or other balanced type which may be single oscillating bullet with spring, damper or balancing weight, and that of thing. To expand the applicability of the balanced type oscillating mole drainer in practical use, it is suggested to develop a new mechanism which perform mole drain with vinyl pipe or filling material such as rice hull.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.6
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• pp.373-379
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• 2001

The weathering rates and change of chemical composition of 6 residual Entisols derived from granite, granite-gneiss, limestone, sandstone, shale, amd basalt in Korea were studied. The chemical composition of each profile with parent rocks were determined using XRF with the physico-chemical properties and the morphology of soils. In the A horizons of all the soils except Euiseong series, the content of clay, organic matter and cation exchange capacity(CEC) showed higher than those of C horizon, but bulk density and pH showed lower than C horizon. Clay content in the soil from sandstone was decrease with soil depth, which may caused by the elluriation. In total element analysis. $SiO_2$ was high in the soil from granite. granite-gneiss, sandstone and compare with basalt and limestone. $Fe_2O_3$ and MgO was high in the soil from basalt, limestone and shale compare with granite. granite-gneiss and sandstone. And ignition loss was particularly high in the soil from basalt and limestone. The rate of element loss was higher in base cations(Ca, K, Mg, Na) than Si, Al, Fe in the soils. The concentrations of $TiO_2$ in the A horizon compare with that of the C horizon was due to resulting from losses of other less stable elements existed. Considering with relative rate of each elements in soils, $SiO_2$ and $Al_2O_3$ which originated from sandstone and granite, granite-gneiss, sandstone, shale, and basalt were lost higher than those from lime tone, but loss of basic cations were more in the soil from limestone which may be rapid weathering of calcite. The magnitude of losses of the overall elements were increased in the order of the soils from sandstone and granite ${\gg}$ limestone and shale) granite-gneiss and basalt.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.197-202
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• 2010

Purpose: Recently, many hospitals have been tried to increase the satisfaction of the outpatients through blood-gathering, exam, result notice and process in a day. Each laboratory has been used the automatic equipment for the rapid requests of the result notice and the increase of the reliability and efficiency. Current automatic equipments that have been limited short TAT(Turn-Around Time)because of the restricted batch lists and 1 tip-5 detectors. The Gamma Pro which is made in Korea to improve the shortcomings of existing automation equipment, complemented with capacity to perform a wide range of domestic automation equipment. In this study, we evaluated the usefulness and reliability of short TAT by comparing Gamma Pro with current automatic equipment. Materials and Methods: We studied the correlation between Gamma Pro and RIA-mat 280 using the respective 100 specimens of low or high density to the patients who were requested the thyroid hormone test (Total T3, TSH and Free T4) in Samsung Medical Center Sep. 2009. To evaluate the split-level Gamma Pro, First, we measured accuracy and carry over on the tips. Second, the condition of optimal incubation was measured by the RPM (Revolution Per Minute) and revolution axis diameter on the incubator. For the analysis for the speed of the specimen-processing, TAT was investigated with the results in a certain time. Result: The correlation coefficients (R2) between the Gamma Pro and RIA-mat 280 showed a good correlation as T3 (0.98), TSH (0.99), FT4 (0.92). The coefficient of variation (C.V) and accuracy was 0.38 % and 98.3 % at tip 1 and 0.39 % and 98.6 % at tip 2. Carry over showed 0.80 % and 1.04% at tip 1 and tip 2, respectively. These results indicate that tips had no effect on carry over contamination. At the incubator condition, we found that the optimal condition was 1.0mm of diameter at 600RPM in 1.0mm and 1.5mm of at 500RPM or 1.0mm and 1.5 mm of diameter at 600 RPM. the Gamma Pro showed that the number of exam times were increased as maximum 20 times/day comparing to 6 times/day by current automatic equipment. These results also led to the short TAT from 4.20 hour to 2.19 hours in whole processing. Conclusion: The correlation of between the Gamma Pro and RIA-mat 280 was good and has not carry over contamination in tips. The domestic automation equipment (Gamma Pro) decreases the TAT in whole test comparing to RIA-280. These results demonstrate that Gamma Pro has a good efficiency, reliability and practical usefulness, which may contribute to the excellent skill to process the large scale specimens.

• Journal of the Mineralogical Society of Korea
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• v.21 no.3
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• pp.313-320
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• 2008

Hectorite was synthesized under hydrothermal conditions and its physicochemical properties have been investigated in terms of temperature, pH, and organic agent to observe the change of doll basal spacing. The IR, CEC, MB, swelling volume and specific surface area of the hectorite were measured for the characterization. The solid/liquid ratio of hectorite to distilled water before mixing with other materials was also determined for its use as a multi-functional material. The $d_{001}$ basal spacing decreased from $12.63\;\AA$ at room temperature to $10.19\;\AA$ at $650^{\circ}C$ in the heating tests. As the pH of hectorite slurry increased. the $d_{001}$ basal spacing decreased. reaching the lowest value of $13.33\;\AA$ at pH 7 and afterward, increased. All the fool basal spacings of the hectorite increased when it was intercalated with the following solvents: $12.86\;\AA$ in diethyl ether, $13.31\;\AA$ in acetonitrile. $13.59\;\AA$ in methanol, $14.05\;\AA$ in ethanol, $15.69\;\AA$ in acetone, and $17.42\;\AA$ in ethylene glycol. Our IR analysis results were in good agreement with those of other researchers. The CEC, MB, swelling volume and specific surface area of hectorite were determined to be 105 cmol/kg, 80 cmol/kg, $68\sim74ml/2g$ and $213m^{2}/g$, respectively. Also, the hectorite to distilled water ratio of 2 to 100 was found to be most favorable for mixing with other materials such as the solvents mentioned above.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.10
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• pp.1353-1360
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• 2011

This study was performed to investigate the antimicrobial effects against food-borne pathogens and antioxidant activity of Rhododendron brachycarpum ethanol-extract. The antimicrobial activity of the extract was determined using a paper disc-diffusion method, and the diameter of the clear zone was measured. The diameter of the clear zone in the presence of 10 mg of extract was maximal against Bacillus cereus among the three tested Gram-positive bacteria and against Escherichia coli O157:H7 among the five tested Gram-negative bacteria. Analysis of the minimum inhibitory concentration (MIC) showed that the extract exhibited a similar efficacy as that of sorbic acid, a well-known chemical preservative. The growth inhibitory effects of the extract at concentrations of 250, 500, 1,000, and 2,000 mg/L on food-borne pathogens were determined against Staphylococcus aureus, Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7. Growth of the microorganisms was not affected by the extract at concentrations up to 250 mg/L, but it was significantly (p<0.05) inhibited by the extract at concentrations higher than 1,000 mg/L. The antioxidant effects of the extract were examined via measurement of DPPH radical scavenging activity, inhibition of reactive oxygen species (ROS) generation using fluorescent dichlorofluorescien (DCF) assay, and prevention of peroxyl radical- and hydroxyl radical-induced supercoiled DNA breakage. The $IC_{50}$ of the extract for DPPH radical scavenging activity was about half that of ${\alpha}$-tocopherol, which was used as a positive control. DCF fluorescence intensity decreased as the concentration of the extract increased, demonstrating that ROS generation was inhibited in a concentration-dependent manner. The ROS inhibitory effect of the extract was higher than that of ascorbic acid. The extract prevented supercoiled DNA strand breakage induced by peroxyl radical and hydroxyl radical. Thus, the results of the present study demonstrate that the extract exhibits antimicrobial effects against food-borne pathogens as well as potent antioxidant capacity, suggesting that R. brachycarpum could be used as a natural antibacterial agent and effective antioxidant in food.

• Journal of Korea Multimedia Society
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• v.14 no.1
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• pp.54-75
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• 2011

PoC(Push-to-talk Over Cellular) is an integrated technology of group voice calls, video calls and internet based multimedia services. If a PoC user can not participate in the PoC session for various reasons such as an emergency situation, lack of battery capacity, then the user can use the PoC Box which has a similar functionality to the MM Box in the MMS(Multimedia Messaging Service). The RTSP(Real-Time Streaming Protocol) method is recommended to be used when there is a transmission session between the PoC box and a terminal. Since the existing VOD service uses a wired network, the packet size of RTSP-based VOD service is huge, however, the PoC service has wireless communication environments which have general characteristics to be used in RTSP method. Packet loss in a wired communication environments is relatively less than that in wireless communication environment, therefore, a buffering latency occurs in PoC service due to a play-out delay which means an asynchronous play of audio & video contents. Those problems make a user to be difficult to find the information they want when the media contents are played-out. In this paper, the following techniques and methods were proposed and their performance and superiority were verified through testing: cross-over dual reception buffering technique, advance partition multi-reception buffering technique, and on-demand multi-reception buffering technique, which are designed for effective picking up of information in media content being transmitted in short amount of time using RTSP when a user searches for media, as well as for reduction in playback delay; and same-priority packetization transmission method and priority-based packetization transmission method, which are media data packetization methods for transmission. From the simulation of functional evaluation, we could find that the proposed multiple receiving buffering and packetizing methods are superior, with respect to the media retrieval inclination, to the existing single receiving buffering method by 6-9 points from the viewpoint of effectiveness and excellence. Among them, especially, on-demand multiple receiving buffering technology with same-priority packetization transmission method is able to manage the media search inclination promptly to the requests of users by showing superiority of 3-24 points above compared to other combination methods. In addition, users could find the information they want much quickly since large amount of informations are received in a focused media retrieval period within a short time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.435-442
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• 2020

This study was conducted to investigate the effect of different raising periods (24 and 48 months) on the physico-chemical quality and fatty acid composition of meat from Korean native black goats. In terms of proximate composition, the meat from the 24-month age-group of the goats contained lower moisture and protein content and higher fat and ash content than that from the 48-month age-group. With an increase in age, moisture and protein content increased, whereas fat and ash content decreased. The pH was higher as was the cooking loss in the meat from the 24-month age-group than in the meat from the 48-months age-group (p < 0.05). However, there was no significant difference in the water-holding capacity and shear force of the meat from the two breeding periods (p > 0.05). A color analysis showed that the meat from the 24-month age-group had higher L*, a*, and b* values than the 48-month age-group (p < 0.05). The fatty acid composition and palmitic acid content increased with an increase in rearing periods, whereas stearic acid and oleic acid content decreased. The proportion of saturated and unsaturated fatty acid content was lower and higher, respectively, at 24 months of age and 48 months of age (p < 0.05).

• Tunnel and Underground Space
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• v.13 no.1
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• pp.52-63
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• 2003

Discontinuities such as faults, fractures and joints in rock mass play the dominant role in the mechanical and hydraulic properties of the rock mass. The key factors that influence on the flow of groundwater are hydraulic and geometric characteristics of discontinuities and their connectivity. In this study, a program that analyzes groundwater flow in the 3D discontinuity network was developed on the assumption that the discontinuity characteristics such as density, trace length, orientation and aperture have particular distribution functions. This program generates discontinuities in a three-dimensional space and analyzes their connectivity and groundwater flow. Due to the limited computing capacity In this study, REV was not exactly determined, but it was inferred to be greater than 25$\times$25$\times$25 ㎥. By calculating the extent of aperture that influences on the groundwater flow, it was found that the discontinuities with the aperture smaller than 30% of the mean aperture had little influence on the groundwater flow. In addition, there was little difference in the equivalent hydraulic conductivity for the the two cases when considering and not considering the boundary effect. It was because the groundwater flow was mostly influenced by the discontinuities with large aperture. Among the parameters considered in this study, the length, aperture, and orientation of discontinuities had the greatest influence on the equivalent hydraulic conductivity of rock mass in their order. In case of existence of a fault in rock mass, elements of the equivalent hydraulic conductivity tensor parallel to the fault fairly increased in their magnitude but those perpendicular to the fault were increased in a very small amount at the first stage and then converged.