• Journal of the Korean Society of Tobacco Science
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• v.20 no.1
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• pp.26-32
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• 1998

This study was conducted to obtain the basic information on the burley tobacco (Nicotiana tabacum L.) curing methods. The effects of the three kinds of curing methods on the dry weight losses during curing, chemical contents and physical properties of cured leaves, and organoleptic and smoking qualities were observed. The dry weight losses during curing was the highest in the stalk curing, and the lowest in the conventional priming. The longer the curing periods was, the more the loss of dry weight. The percent of the excessive dried leaves was high and the price per kilogram was low in the conventional priming. The chemical contents and the physical properties of the cured leaves in the conventional priming were similar to those of yellowing or browning stage of curing. But, the chemical contents and the physical properties of the cured leaves in the stalk curing were comparable to those of the air curing. The smoking quality was the best in the stalk curing.

• Elastomers and Composites
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• v.25 no.1
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• pp.13-19
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• 1990

The purpose of this study is to estabilish the synthetic condition of polyurhethane elastomer for excellent properties. Polyurethane elastomer which have different NCO percentage and hard segment contents was synthesized by casting method. And the effects of hard segment contents were investigated by analytical methods such as IR, DSC, etc. [NCO]/[OH] ratio was proper at the range $1.02{\sim}1.05$. By IR absorption peak($1250cm^{-1}$) which indicate interurethane hydrogen bond it was confirmed that hard segment were crystallized. Melting point that was determined by DSC showed the effects of hard segment contents, phase mixing and crystalline size.

• Journal of Ecology and Environment
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• v.32 no.4
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• pp.295-304
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• 2009

To understand the properties of soil in Dokdo, we collected soil samples from 12 locations on Seodo and 23 locations on Dongdo, in Dokdo of Gyeongsangbuk-do Province in 2007-2008 and analyzed the soil's physical and chemical characteristics. Sand comprises the largest component (49.37%) of Dokdo soil, followed by silt (40.70%) and clay (9.93%). The soil structure consists mostly of sand loam, followed by loam and silt loam. The pH level of soils from Dokdo varied dramatically among sampling sites and seasons, ranging from 3.36 to 8.02. The total ion content of Dokdo soil also varies greatly among survey places and periods, but in general the total ion content was high in summer when vegetation develops, and low in spring. The exchangeable cation contents of the soil showed low levels in samples where the soil pH was low, including habitats dominated by Agropyron tsukushiense var. transiens and Echinochloa crus-galli, whereas the exchangeable cation contents were high where the organic contents were high, as in habitats dominated by Liriope platyphylla and Artemisia japonica subsp. littoricola. Soil N contents varied greatly among survey sites and higher N contents were found in soil inhabited by Chenopodiaceous plants than in habitats inhabited by other plants. The substantial differences in phosphorus contents among sites were related to excrement of black-tailed gulls. To understand the basic physical and chemical features of the soil on Dokdo, it will be necessary to conduct seasonal and long-term research on soil pH, ion contents, organic contents, N and P, as well as obtaining precise data from samples collected at different depths.

• 한국해양학회지
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• v.5 no.1
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• pp.14-29
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• 1970

Tidal variations of various chemical constituents in the laver bed sea waters in Wan Do Gun were determined over one spring tidal cycle from Oct. 1968 to Feb. 1969. Total ranges and means of the contents at Pyung-il Do and Wan Do are as follows. Although the average monthly variations of each content at Pyung-il Do were similar to those at Wan Do, most of the contents at Pyung-il Do were at a slightly higher level than at Wan Do. The values of silicate-silicon, phosphate- phosphorus and soluble iron, however, showed high levels at Wan Do. Chlorinity, magnesium, calcium, dissolved oxygen, silicate-silicon and phosphate-phosphorus contents increased from Oct. 1968 to Feb. 1969, though the content of soluble iron decreased before December and slightly increased in January and February. The average monthly variations of ammonia-nitrogen and nitrate-nitrogen contents were irregular. The nitrite-nitrogen content appeared in trace amounts in the months with a comparatively high water temperature, i.e., October and November, but in midwinter it was undetected. The ranges of the tidal variations of the contents of each chemical constituent were not significantly wide, though the contents varied excessively by the hour, and this may show the irregularity of the water quality in Wan Do Gun coastal area. As a rule, no regular tidal variation of the chlorinity was observed except slightly decreased value at ebb tide at Wan Do. In general, although the pattern of the variations of calcium and magnesium contents were similar to that of the chlorinity, no definite relationships between these constituents and chlorinity were observed. Tidal variations of the dissolved oxygen content, nutrient salts and soluble iron were irregular.

• Korean Journal of Materials Research
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• v.16 no.12
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• pp.731-738
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• 2006

It is seriously considered using Al CMP (chemical mechanical planarization) process for the next generation 45 nm Al wiring process. Al CMP is known that it has a possibility of reducing process time and steps comparing with conventional RIE (reactive ion etching) method. Also, it is more cost effective than Cu CMP and better electrical conductivity than W via process. In this study, we investigated 4 different kinds of slurries based on abrasives for reducing scratches which contributed to make defects in Al CMP. The abrasives used in this experiment were alumina, fumed silica, alkaline colloidal silica, and acidic colloidal silica. Al CMP process was conducted as functions of abrasive contents, $H_3PO_4$ contents and pressures to find out the optimized parameters and conditions. Al removal rates were slowed over 2 wt% of slurry contents in all types of slurries. The removal rates of alumina and fumed silica slurries were increased by phosphoric acid but acidic colloidal slurry was slightly increased at 2 vol% and soon decreased. The excessive addition of phosphoric acid affected the particle size distributions and increased scratches. Polishing pressure increased not only the removal rate but also the surface scratches. Acidic colloidal silica slurry showed the highest removal rate and the lowest roughness values among the 4 different slurry types.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1085-1088
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• 2011

Heavy metal concentration as well as chemical composition were surveyed in commercial liquid pig manure to provide the basic information for mitigation research of hazardous material to agro-product. Seventy-five samples of liquid pig manure were collected and analyzed from 2009 to 2010 nationwide. Average contents of T-N, $P_2O_5$, and $K_2O$ were 0.29%, 0.08%, and 0.11%, respectively. The contents of heavy metals ranged from 0.001~0.083 for As, 0.001~0.108 for Cd, 0.002~0.495 for Cr, 0.07~47.8 for Cu, ND~0.005 for Hg, 0.035~1.033 for Ni, ND~0.291 for Pb, and $0.75{\sim}342.4mg\;L^{-1}$ for Zn, respectively. It was noted that among 75 samples, only four samples exceeded the Zn guideline ($130mg\;L^{-1}$) of liquid fertilizer derived from livestock manure but others were not exceeded the regulation.

• Elastomers and Composites
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• v.54 no.2
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• pp.97-104
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• 2019

Emulsion styrene-butadiene rubber silica wet masterbatch (ESBR silica WMB) technology was studied to develop highly filled and highly dispersed silica compounds, involving the preparation of a composite by co-coagulating the modified silica and the rubber latex in a liquid phase. Previous studies have shown that when manufacturing ESBR silica WMB/Butadiene silica dry masterbatch (BR silica DMB) blend compounds, preparing BR silica dry masterbatch and mixing it with ESBR silica WMB gave excellent results. However, WMB still has the problem of lower crosslink density due to residual surfactants. Therefore, in this study, tetrabenzylthiuram disulfide (TBzTD) was added instead of diphenyl guanidine (DPG) in the ESBR silica WMB/BR silica DMB blend compounds and sulfur/CBS contents were increased to evaluate their cure characteristics, crosslink densities, mechanical properties, and dynamic viscoelastic properties. TBzTD was found to be more effective in increasing the crosslink density and to produce superior properties compared to DPG. In addition, with increasing sulfur/CBS contents, mechanical properties and rolling resistance were enhanced due to high crosslink density, but the abrasion resistance was not significantly changed because of the toughness.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.6 s.107
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• pp.95-102
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• 2005

This study was carried out to find out the heavy metal contents and the physico-chemical properties for the improvement of dredged soils which widely exist in lowlands of Korea. At first all the average heavy metal contents were close to background level and were much lower than concern level of the Soil Environment Conservation Act of Korea. And the results of physical analyses of soils showed on the average $2.46\~2.74 Mg/m^3$ in Particle density, $0.45\~2.45 kg/kg$ in soil water contents, $0.34\~0.90 Mg/m^3$ in bulk density, $0.67\~0.87m^3/m^3$ in porosity, $2.18\times10^{-5}\~1.20\times10^{-8} m/s$ in saturated hydraulic conductivity, R0.12\~0.65 m^3/m^3$ in available water contents. Finally the results of chemical analyses of soils showed on the average $6.5\~8.2\;in\; pH,\;5\~48 g/kg\;in\; OM,\;0.48\~4.51g/kg\;in\;T-N,\;19\~25mg/kg$ in available phosphate, $0.28\~11.80 dS/m\;in\;EC,\;8.7\~38.1cmol/kg$ in CEC, respectively Accordingly, the physicochemical properties of soils ought to be analyzed accurately before dredging for effective using of dredged soils. And it will be more effective, if the dredged soils are used with proper balance among each content of components with consideration to the physicochemical properties of common soils.

• Korean Journal of Medicinal Crop Science
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• v.18 no.2
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• pp.118-125
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• 2010

This study was carried out to determine changes in general chemical composition, free sugars, physicochemical properties of extract, and ginsenoside contents depending upon processing methods. Ginseng roots harvested from the same field were employed for the processing into white ginseng (WG), taegeuk ginseng (TG), red ginseng A (RGA, steamed one time), and red ginseng B (RGB, steamed three times). The fat content decreased by increasing duration of treatment and number of steaming treatment. On the other hand, there was no significant variation in contents of ash and carbohydrate depending on processing methods. Contents of sucrose and maltose was higher in Taegeuk and red ginseng than those of white ginseng. Steamed ginseng root (taegeuk and red ginseng root) showed higher amount of water extractable solid than the unsteamed white ginseng, but the variation of crude saponin content was not distinctive depending on processing methods. The contents of total ginsenosides increased by the order of white, taegeuk, red A, and red B root. In summary, chemical composition and total ginsenoside content were different according to part of root and processing methods, thus implies the importance of quality control as well as pharmacological activity of ginseng root.

• KSBB Journal
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• v.26 no.2
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• pp.112-118
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• 2011

Contents of amino acids, vitamins, and minerals as well as its antioxidant activitiy of Laminaria japonica water extract have been analyzed for preparation of functional foods and cosmetic products. From the analysis of total amino acids, eighteen kinds of amino acids were found in the water extract of Laminaria japonica. Among total amino acids, the order of contents was glutamic acid (2.07 mg/g), alanine (0.51 mg/g), aspartic acid (0.44 mg/g), glycine (0.34 mg/g), and valine (0.34 mg/g). In case of free amino acids, glutamic acid (0.95 mg/g), prolin (0.54 mg/g), aspartic acid (0.44 mg/g), leucine (0.07 mg/g), and phenylalanine (0.07 mg/g) were dominant compositions. Vitamin E was only detected in water extract of Laminaria japonica. The mineral contents were as follows: K 752.60 mg, Na 259.20 mg, Ca 80.20 mg, P 29.50 mg, and Fe 8.32 mg based on 100 g Laminaria japonica water extract. The nitrite scavenging activity of the extract were gradually increased with the extracts contents to 86.2% at concentration of 100 mg/mL and DPPH radical scavenging activity of the extracts were 86.4% at concentration of 50 mg/mL.