• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.400-409
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• 2015

This study examined the plant growth and development characteristics of leafy vegetables on the hydroponic substrates of waste wood chips, radiate pine chips, and mat type of waste wood chips. The bulk density of waste wood chips and radiata pine chips were $0.2g/cm^3$ and $0.16g/cm^3$, respectively. The moisture retention properties of both the radiata pine chips and waste wood chips were found to be similar but not better than those of the control rock wool and coco peat hydroponic substrates. The moisture retention property of the mat type was found to be the lowest. The chemical analysis of waste wood hydroponic substrates (w/v) was as follows.; The pH was 6.59, electric conductivity was 6.76 dS/m, total nitrogen content was 0.5%, C/N ratio was 113%, phosphorus was 10.1 ppm, potassium was 77 ppm, calcium was 531 ppm, magnesium was 49 ppm, and sodium was 96 ppm. The results from the radiata pine chemical analysis showed that it had a pH of 5.29, electric conductivity of 4.49 dS/m, total nitrogen content of 0.32%, C/N ratio of 180%, phosphorus of 6.4 ppm, potassium of 83 ppm, calcium of 97 ppm, magnesium of 29 ppm, and sodium of 59 ppm. Except for the plants grown in mat type, the developmental characteristics of the plants grown in rock wool and coco peat hydroponic substrates were similar. Based on the results of the experiment, waste wood resources may possibly be used as an organic solid medium in place of the existing rock wool and coco peat medium.

• Investigative Magnetic Resonance Imaging
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• v.4 no.1
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• pp.27-33
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• 2000

Purpose: To determine the electronic spin relaxation times, $T_{le}$, of three commercially available Gd-chelated MR contrast agents, Gd-DTPA, Gd-DTPA-BMA and Gd-DOTA, using Electron Paramagnetic Resonance(EPR) technique. Material and Methods: The paramagnetic MR contrast agents, Gd-DTFA(Magnevist) , Gd-DTFA-BMA(OMNISCAN) and Gd-DOTA(Dotarem), were used for this study, The EPR spectra of these contrast agents, which were prepared 2:1 methanol/water solution, were obtained at low temperatures, from $-160^{\circ}C~20^{\circ}C$. The glassy-state EPR spectra for these contrast agents were then fitted by the simulation spectra generated with different zero-field splitting (ZFS) parameters by a computer simulation program 'GEN', which generates the EPR powder spectrum using a given ZFS in $3{\times}3$ tensor. Finally, the spin relaxation times of the contrast agents were then determined from the $T_{2e}$, D, and E values of the best simulation spectra using the McLachlan's theory of average relaxation rate. Results: The electronic transverse spin relaxation times, $T_{2e}'s$, of Gd-DTPA, Gd-DTPA-BMA and Gd-DOTA were 0.113ns, 0.147ns and 1.81ns respectively. The g-values were 1.9737, 1.9735 and 1.9830 and the electronic spin relaxation times, $T_{1e}'s$, were 18.70ns, 33.40ns and $1.66{\mu}s$, respectively. Conclusion: The results of these studies reconfirm that the paramagnetic MR contrast agents with larger ZFS parameters should have shorter $T_{1e}'s$. Among three contrast agents used for this study, Gd-DOTA chelated with cyclic ligand structure shows better electronic property then the others with linear structure. Thus, it is concluded that the exact determination of ZFS parameters is the important factor in evaluating relaxation enhancement effect of the agents and in developing new contrast agents.

• Korean journal of food and cookery science
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• v.18 no.6
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• pp.692-697
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• 2002

The purpose of this study is to investigate the characteristics of the doughs and noodles cooked with the pea starch-wheat composite flour which was substituted with 20% and 30% of pea starch for the flour by the mechanical and sensory evaluation. Wheat dough had the most cohesive property among various composite non.(p＜0.05) There was no significant differences in weight gain after cooking among various noodles. The more the pea starch was subsituted, the lighter the color was shown by increasing L value. It was also noted that the b value was decreased significantly. While pea starch noodle were more transparent in appearance and less smooth in the texture, corn starch-wheat composite flour noodle was sorter in the texture significantly. There was no significant difference on the hardness between wheat and pea stach composite flour noodles. There were also no significant differences in stickiness, chewiness and overall acceptability among various noodles. Considering mechanical and sensory results, the composite flour with 20% substitution of pea starch for flour was more suitable for the production of the noodle than those of 30% substitution of pea starch.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.2
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• pp.82-89
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• 2014

Purpose: The purpose of this study was to observe the change of viscoelastic properties of dental resin cements during polymerization. Materials and methods: Six commercially available resin cement materials (Clearfil SA luting, Panavia F 2.0, Zirconite, Variolink N, RelyX Unicem clicker, RelyX U200) were investigated in this study. A dynamic oscillation-time sweep test was performed with AR1500 stress controlled rheometer at $32^{\circ}C$. The changes in shear storage modulus (G'), shear loss modulus (G"), loss tangent (tan ${\delta}$) and displacement were measured for twenty minutes and repeated three times for each material. The data were analyzed using one-way ANOVA and Tukey's post hoc test (${\alpha}$=0.05). Results: After mixing, all materials demonstrated an increase in G' with time, reaching the plateau in the end. RelyX U200 demonstrated the highest G' value, while RelyX Unicem (clicker type) and Variolink N demonstrated the lowest G' value at the end of experimental time. Tan ${\delta}$was maintained at some level and reached the zero at the starting point where G' began to increase. The tan ${\delta}$and displacement of the tested materials showed similar pattern in the graph within change of time. The displacement of all 6 materials approached to zero within 6 minutes. Conclusion: Compared to other resin cements used in this study, RelyX U200 maintained plastic property for a longer period of time. When it completed the curing process, RelyX U200 had the highest stiffness. It is convenient for clinicians to cement multiple units of dental prostheses simultaneously.

• The Korean Journal of Zoology
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• v.30 no.1
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• pp.53-70
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• 1987

The morphological study on the parenchymal cells in the adult planaria performed to observe their cytochemical and ultrastructural characteristics. The results are as follows. Nine types of cells are found in parenchyma. 1. Free parenchymal cell: These cells contain several chromatoid bodies around the nucleus. Heterochromatins are evenly dispersed in large nucleus. These cells are abundant in free ribosomes. 2. Fixed parenchymal cells: These cells have well-developed granular endoplasmic reticulum, mitochondria and Golgi complex but they contain the cytosols exhibiting electron-lucencies. 3. Rhabdite-forming cells: These cells contain the electron-dense rhabdite granules of up to about 0.3 x 0.9 $\mu$m in size. Rhabdite-forming cells have well-developed cell organelles, granular endolplasmic reticulum, mitochondria and Golgy complex. 4. A-type of basophilic granule cells: These cells contain irregularly-shaped granules exhibiting alcianophilia. These granules surrounded by a limited membrane, approximately 1.4 x 0.7 $\mu$m in size, are accumulated in the cytoplasm. 5. C-type of basophilic granule cells: These cells contain electron-dense granules of less than 0.2 $\mu$m in size, which exhibit PAS- positive reaction. This type of granule is also found in the muscle layer of parenchyma. 6. D-type of basophilic granule cells: This type of granule cell occurs only in the parenchyma around reproductive organ. The granules have cytochemical characteristics that they exhibit strongly positive reaction with PAS and weakly eosinophilic property. These electron-dense granules, which are 0.2 to 0.6 $\mu$m in length, have oval shapes. 7. E-type of basophilic granule cells: These cells are found only in the parenchyma around re productive organ. The granules contained in a small number in the cell, exhibit PAS-positive reaction and have an average size of 0. 2pm. 8. Eosinophilic granule cells: These cells contain a large number of eosinophilic granules which have relatively diverse sizes from 0.3 x 0.2 to 0.8 x 0.4 $\mu$m. Most of granules are round or irregularly-shaped and highly electrondense. These cells have an array of well-developed granular endoplasmic reticulum of which cisternae are distened. 9. Transparent granule cells contain electron-lucent granules which exhibit negative reactions with three kinds of cytochemical methods used in this experiment.

• Journal of the Korea Concrete Institute
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• v.16 no.1 s.79
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• pp.79-87
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• 2004

The qualify of lightweight aggregate made from waste PET bottle(WPLA) and the workability, the unit weight and strength property of concrete with WPLA were investigated for the purpose of recycling the waste PET bottles as lightweight concrete fine aggregate. This study indicated a good result that WPLA should be replaced with less than $50\%$ of natural fine aggregate. When WPLA was replaced with $50\%$ of natural fine aggregate, the specific gravity and water absorption of mixed fine aggregate were greatly reduced about 23 and $75\%$ respectively in comparison with those of river sand. The quality of WPLA affected on the properties of lightweight aggregate concrete. The workability of fresh concrete with WPLA(WPLAC) was improved with increasing the replacement ratio of WPLA and water cement ratio. Slump increasing ratio of the former showed about $45 {\~} 120\%$ because that a specific gravity of fine aggregate was decreased from 2.6 to 1.7. The unit weight of concrete with $75\%$ WPLA was decreased about $17\%$ in comparison with that of control concrete. Furthermore, the compressive strength of concrete with 25 and $50 \%$ WPLA at the age of 28 days increased higher than 30 MPa regardless with water cement ratio (W/C=45, 49 and $53\%$) of this study. Specific strength of concrete with $25\%$ WPLA, $15.11{\times}10^3 MPa{\cdot}m^3/kg$, was higher than that of contro concrete in water cement ratio of $49\%$. The compressive strength-splitting tensile strength ratio and compressive strength-modulus of elasticity ratio of WPLAC were similar to that of nomal lightweight aggregate concrete. This results showed a good estimation that WPLA will be able to recycled as a fine aggregate for lightweight concrete.

• Food Science and Preservation
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• v.14 no.2
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• pp.148-153
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• 2007

The chemical components of flesh persimmon flowers (petal and calyx), and the qualify of hot-water extracts (teas) prepared from powders of these flower parts, were investigated In flesh petal and calyx, the contents of moisture, crude protein, crude lipid, and carbohydrate were 84.8% 0.4% 0.3% and 13.7% respectively. The values were not significantly different when the two tissues were compared. In petal and calyx respectively, the crude ash values were 0.5% and 1.1% of flesh weights, the vitamin C content were 192.3mg% and 392.7ng%, the flavonoid levels were 98.4 mg% and 355.2mg% and the carotenoid content were 0.8mg% and 3.8mg%. Hot air and freeze drying methods applied to petals, prior to powder preparation, did not affect the levels of soluble solids or soluble annins. Extract from calyx had higher L values, higher ${-\alpha}$ values, more soluble tannins, greater 1,1-diphenyl-2-picrylhy-drazylradical-scavenging activities, me lower pH values, than did exracts from petal. Fructose and glucose were higher in petal extract than in calyx extract, but sucrose was higher in calyx extracts. Extract of freeze-dried powdered petals had significantly higher free sugar levels than did exracts from petals dried with hot air. The major organic acids in extracts were citric acid, oxalic acid, and malic acid. The levels of organic acids were inversely related to free sugar levels in all flower parts and after all drying methods tested. Sensory tests of aroma, taste and overall acceptability yielded scores above medium for all teas, regardless of the flower part powdered, or the drying method used. The results show that the petal and calyx of persimmon may be used to make tea and perhaps other foods.

• Journal of the Korean Wood Science and Technology
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• v.12 no.2
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• pp.20-26
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• 1984

This study was carried out to investigate the influence of chemical type and its retention in the fire-retardant treated plywoods on the static bending strength, a property peculiar to plywood. Being soaked in 20% aqueous solution of $(NH_4)_2SO_4$, $NH_4H_2PO_4$, $(NH_4)_2HPO_4$. Borax-Boric acid and Minalith for 3 to 12 hours at three-hour intervals and redried at $120^{\circ}C$ in hot press, the treated plywoods were put to static bending test. The values of chemical treated plywoods in Stress at proportional limit, Modulus of elasticity, Modulus of rupture and Work per unit volume to proportional limit were widely higher than those of water treated plywoods(control) and Borax-Boric acid treatment showed the highest value in the four mechanical data. And the bending strength of fire-retardant treated plywoods increased with the extension of soaking time or the increase of chemical retention in themselves. Borix-Boric acid was the desirable fire-retardant for thin plywood in view of mechanical strength and soaking defects in this study.

• Korean Journal of Plant Resources
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• v.24 no.4
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• pp.413-418
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• 2011

This study was carried out to establish a proper cultivation site and diagnose the drought-tolerance of Aster scaber and Synurus deltoides leaves by using Pressure-volume curves. In order to measure pressure-volume (P-V) curves, Aster scaber and Synurus deltoides were cut off above ground part and the tip of the cutting were placed in water, which was covered with a plastic bag. Samples were kept overnight (about 12 hours) in darkness at room temperature (20~25$^{\circ}C$) to achieve maximal turgor (full saturation). The pressure in the chamber was gradually increased from 0.3MPa to 1.8MPa by nitrogen gas. After measured, leaf samples were dried at 80$^{\circ}C$ for 48 hours and dry weight of each samples were determined. The result of the original bulk osmotic potential at maximum turgor ${\Psi}^{sat}_o$ sat was lower -0.8 MPa in Aster scaber leaves than -0.7 MPa Synurus deltoides leaves. Also the osmotic potential at incipient plasmolysis ${\Psi}^{tlp}_o$ in Aster scaber leave was -0.9 MPa. In contrast, the value of maximum bulk modulus of elasticity $E_{max}$ of Aster scaber leaves were approximately two folds higher than that of Synurus deltoides leaves. The values of the relative water content at incipient plasmolysis $RWC^{tlp}$ are all above 90% showing that the function of osmoregulation is somewhat better, and Vo/DW, Vt/DW, Ns/DW of Synurus deltoides leaves were approximately 1~2 times higher than that of Aster scaber leaves. Thus, responses to water relations of Aster scaber and Synurus deltoides such as ${\Psi}^{sat}_o$, ${\Psi}^{tlp}_o$, $E_{max}$, ${\Psi}_{P,max}$, $RWC^{tl}$ were shown that the Aster scaber leaves was slightly higher drought-tolerance than Synurus deltoides leaves. However, in both of Aster scaber and Synurus deltoides, occurring incipient plasmolysis at the high water content, have a relatively lower drought-tolerance property indicating that growth of these plants are cultivated appropriate in high moisture soil sites.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.3
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• pp.159-168
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• 2005

This experiment was carried out during the period from May to October 1998 to determine the effect of fermented sawdust swine manure application (SSM) on the herbage production of Japanese millet and soil properties in the Cheju brown volcanic ash soil. The randomized block design (T1 : basic chemical fertilizer, N 200 kg/ha + $P_2O_5\;300 kg/ha+K_2O$ 200kg/ha ; T2 : 1/2 basic chemical fertilizer, N $100+P_2O_5\;150+K_2O$ 100kg/ha; T3 : 1/2 basic SSM, N 100kg/ha, T4:basic SSM, N 200kg/ha; T5:2 times basic SSM, N 400 kg/ha ; T6:4 times basic SSM, N 800 kg/ha) was used. At the same application level of nitrogen 200kg/ha, the application of $100\%$ chemical fertilizer (T1) had significantly lower dry matter yield than that of $50\%$ chemical fertilizer and $50\%$ SSM (T2) or $100\%$ SSM (T4)(p<0.01). Dry matter yield increased with an increase of SSM application to N 400kg/ha level but decreased at N 800 kg/ha level. P, K and Ca contents of Japanese millet tended towards to decrease with an increase of SSM level. The application of chemical fertilizer lowered P and K content of Japanese millet in comparison with that of SSM (p<0.05). pH, available phosphorus. exchangeable potassium, Ca and Mg content of soil studied showed a significant increase with an increase of SSM application level (p<0.05). However, at the same application level of N 200kg/ha, there was statistically no significant difference between chemical fertilizer and SSM in those contents of soil after experiment. The bacterial number of soil among microbial population increased with an increase of SSM level, in June, 1998 (p<0.05), but there was no regular tendency, in October. The rate of bacteria to fungus in soil had a tendency to decrease with an increase of SSM level. In conclusion, it is recommended to use N 400kg/ha of SSM or N 100 kg/ha of chemical fertilizer+N 100 kg/ha of SSM for Japanese millet.