• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.11
• /
• pp.5326-5336
• /
• 2012

Most middle and high school students in Korea use internet for gaming and recreation. This study aimed to classify middle and high school students according to amount of time they spend playing games and analyze relationship domestic factors. Weekday game times and environmental factors of the adolescents in Korea. The group with average game time of 30 min, 0:30-1:30 hours, 1:30-3:00 hours, over 4:00 hours. Subjects in this study were 6,487 middle and high school students. For the category "thoughts about game characters", the group with average game time of 1:30~3:00 hours replied "not at all" but the group with average game time of over 4:00 hours replied "sometimes", which was significantly different from the previous group. Similarly, for the category "lack of time for homework", the group with average game time of 1:30~3:00 hours replied "not at all", which significantly differed from the "sometimes" response from the group with average game time. For satisfaction with interest, "average" was the most frequent response from all the groups. Analyzing correlation of factors influencing game addiction in subjects with game time showed that factors related to game addiction diagnosis and academic performance were especially different in the group with average game time of over 4:00 hours compared to other groups. Nowadays internet has taken a large and significant part of our life such that a life without internet is hard to imagine, and our dependency on internet has risen at the same time. Accordingly, education on appropriate utilization and correct usage of internet to youths who lack self-control and judgment is very needed.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.67 no.4
• /
• pp.362-366
• /
• 2022

This study was conducted to find out the changes in the growth and yield of ginseng and the changes in the soil of direct-seeded ginseng fields after applying different compaction strengths. As a result of surface soil compactions, the topsoil hardness increases as the strength of treatment increases in the first year but topsoil hardness increased only by applying 30 kg weight of compaction in the second year. The germination rate was significantly higher (79.4% and 79.1% at 25 kg and 30 kg, respectively) in 1st year after the application of soil surface compactions. The longest plant was 35.7 cm in 4- years old ginseng in the control and the height was 26.9 cm and 26.5 cm in the soil surface compactions of 25 kg and 30 kg, respectively. In addition, the higher weight of ginseng roots of 31.3 g and 30.3 g were observed after applying 25 kg and 30 kg compaction treatment, and the lowest root weight of 25.6 g was in the control. Therefore, it is shown that after sowing, applying the weight of 25 kg to 30 kg for soil surface compaction is appropriate for better yield in direct seeded cultivation of ginseng at paddy fields.

• Applied Chemistry for Engineering
• /
• v.34 no.6
• /
• pp.674-678
• /
• 2023

The effect of Pt was investigated to the catalytic methane decomposition of CH₄ to H₂ over Pt(1)-Fe(30)/MCM-41 and Fe(30)/MCM-41 using a fixed bed flow reactor under atmosphere. The Fe₂O₃ and Pt crystal phase behavior of fresh Pt(1)-Fe(30)/MCM-41 were obtained via XRD analysis. SEM, EDS analysis, and mapping were performed to show the uniformed distribution of nano particles such as Fe, Pt, Si, O on the catalyst surface. XPS results showed O^2-, O^- species and metal ions such as Pt⁰, Pt²⁺, Pt⁴⁺, Ft⁰, Fe²⁺, Fe³⁺ etc. When 1 wt% of Pt was added to Fe(30)/MCM-41, automic percentage of Fe2p increased from 13.39% to 16.14%, and Pt4f was 1.51%. The yield of hydrogen over Pt(1)-Fe(30)/MCM-41 was 3.2 times higher than Fe(30)/MCM-41. The spillover effect of H₂ from Pt to Fe increased the reduction of Fe particles and moderate interaction of Fe, Pt and MCM-41 increased the uniform dispersion of fine nanoparticles on the catalyst surface, and improved hydrogen yield.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.37 no.4
• /
• pp.372-376
• /
• 1992

This experiment was conducted to determine hay making time on the drying period, hay moisture content, hay loss content, yield and forage quality of Italian ryegrass in paddy field. Plant height increased rapidly from middle of April, and leaf weight rate were 55.6% at April 20 and 18.9% at May 30. Moisture content and loss content of hay were 17.1-20.5% and 10.2-15.0%, respectively, at drying for 4 days from May 10 to May 30. As the growth stage later, crude protein, fat and ash contents reduced, but crude fiber and NFE contents increased. Dry matter and TDN yield at the cutting of May 20 and May 30 increased to 17-18% and 5-11%, respectively, than those of April 20＋May 30.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2000.05a
• /
• pp.38-44
• /
• 2000

To determine the optimum sowing date and nursery period in Alisma piantago in the southern area of Korea, Alisma plantago local cultivar was grown under three different sowing dates and nursery periods. The plant height, leaf width and leaf length at the area sown on the seedbed in June 30 and conducted the growing seedling in 30 days is 12.1cm, 2.5cm and 3.1cm respectively and it shows tess decrease than that of plant height, leaf width and leaf length with 12.3cm, 2.6cm and 3.2cm respectively which was sown on the seedbed in June 20 and carried out the growing seedling in 30 days, and it also shows less decrease than that of plant height, leaf width and leaf length with 15.2cm, 3.1cm and 5.2cm respectively at the area sown on the seedbed in July 10 and condected the growing seedling in the same date. The stem length, number of stems and diameter of root at the area sown on the seedbed in June 30 and conducted the growing seedling in 30 days is 31cm, 11 and 3.7cm respectively and it shows more increase than that of stem length, number of stem and diameter of and on the other hand shows tess decrease than that of stem length, number of stems and diameter of root with 30cm, 10cm, 35cm respectively which was sown on the seedbed in 30 days, and on the other hand shows less decrease than that of stem length, number of stems and diameter of root with 32cm,13cm,3.9cm respectively at the area sown on the seedbed in July 10 and conducted the growing seedling in the same date, The fresh yield of roots at the area sown on the seedbed in June 30 and conducted the growing seedling in 30 days is 431.4Kg/10a and it shows more increase of 26.9Kg than that of fresh yield of root with 410.59g110a which was sown on the seedbed in lune 20an4 carried out the growing seedling in 30 days, and it also shows more increase of 7Kg than that of fresh yield of root with 430.4Kg/10a at the area sown on the seedbed in July 10 and conducted the growing seedling in the same date. The dry yield of roots at the area on the seedbed in June 30 and conducted the growing seedling in 30 days is 351.9Kg110a which was sown on the seedbed in June 20 and carried out the growing seedling in 30 days, and it also shows more increase of 16.4Kg than that of dry yield of root with 335.4Kg110a at the area sown on the seedbed in July 10 and conducted the growing seedling in the same date. Therefore, the seedling period of proper seedbed for high yield bumper crop of Alisma plantago for exporting to Japan is June 30 and the number of days for seedling is 30 days.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.33 no.4
• /
• pp.329-335
• /
• 1988

[n order to find out the effects of nitrogen fertilizer and planting density on the leaf characteristics of high yielding cultivars of rice, Dongjin (Japonica type) and Samkang (Tongil type) were .grown under two nitrogen levels (150 and 250 kg N/ha) and three planting densities (30 ${\times}$ 15 cm, 30 ${\times}$ 12 cm, 30 ${\times}$ 9 cm. Leaf blade, sheath and dry weight of individual leaf. the number of green leaves after flowering were measured. Samkang was characterized as longer and wider leaf blade and sheath than Dongjin, less sensitive to nitrogen fertilizer and planting density, and higher proportions of green leaves after flowering. These morphological characteristics of Samkang caused an increase of grain yield by 30 per cent.

• Korean Journal of Food Science and Technology
• /
• v.37 no.6
• /
• pp.939-943
• /
• 2005

Jinyangju, Korean rice wine, has been traditionally brewed using unique glutinous rice produced only in Haenam, Korea. Because this glutinous rice is expensive, possibility of partial replacement by lower costing non-waxy rice to make Jinyangju was investigated. Both chemical and sensory properties of the rice wine made from different levels of non-waxy rice replacement were determined. Total acidity, pH, total sugar content, and alcohol content of rice wines made with varying replacement levels of non-waxy rice (0, 30, 50, and 70%) were respectively as follows: 1.02, 0.98, 1.1, and 1.1%; 3.76, 3.83, 3.64, and 3.58; 6.22, 6.31, 4.58, and 4.73%; 14.2, 14.8, 15.6, and 15,2%. Highest overall acceptabilities in sensory test including color, flavor, odor, and overall favorite were 4.45, 4.73, 4.45, and 3.55, respectively, at 30% non-waxy rice replacement.

• Magazine of the Korea Concrete Institute
• /
• v.15 no.4
• /
• pp.30-33
• /
• 2003

• 한국전산유체공학회:학술대회논문집
• /
• 2008.08a
• /
• pp.30.4-30.4
• /
• 2008

• The Korean Journal of Pain
• /
• v.30 no.4
• /
• pp.241-242
• /
• 2017