• Journal of Mushroom
• /
• v.13 no.3
• /
• pp.203-206
• /
• 2015

'Baekjung' adaptable to high temperature was made by crossing between monokaryon derived from selfing of brown strain and monokaryon derived from Korea white strain. In the condition that temperature is maintained at $10^{\circ}C$ without low temperature of $4^{\circ}C$ suppressing treatment and wrapping during cultivation period, it showed good productivity than Uri1ho(control). The optimum temperature of mycelial growth was $30^{\circ}C$ and that of fruiting body initiation and development were $14^{\circ}C$ and $7^{\circ}C$, respectively. The days for the fruiting and yield were 7 days and $277{\pm}11.2$ g per 1,100 ml bottle, respectively. This variety needed high concentration of carbon dioxide up to 4,000 ppm for the good quality.

• Korean Journal of Food Science and Technology
• /
• v.25 no.4
• /
• pp.327-333
• /
• 1993

The processing conditions and quality of sardine surimi were examined: Raw sardine meat was separated, washed in 0.2% $NaHCO_3$ and 0.15% NaCl solution, and then dewatered by centrifuge. The dewatered sardine meat was chopped, mixed with 20% emulsion curd (soybean protein : water : refined sardine oil=1:5:2.6), 4% sorbitol, 4% sucrose, 0.2% polyphosphate and 0.1% sodium erythorbate by stone mortar. The mixed sardine meat was frozen with contact freezer, packed in carton box and then stored at $-25{\pm}2^{\circ}C$. The moisture, crude protein and lipid contents of the sardine surimi product was 73.3%, 15.0% and 6.9%, respectively. Fatty acid composition of product consisted of 28.8% of saturates, 24.3% of monoenes and 47.7% of polyenes and the major fatty acids were 16:0, 20:5, 18:1, 22:6 and 16:1. The results of changes in POV, TBA value, fatty acids, texture and sensory score of products during frozen storage showed that lipid oxidation and freeze denaturation of product could be retarded, and flavor enhanced by addition 20% emulsion curd and 0.1% sodium erythorbate. In an attempt to apply sardine surimi in producing surimi-based product, it was concluded that pollack surimi could be substituted with sardine surimi up to 40% without showing any significant changes in texture and taste of surimi-based product.

• Asian Journal of Turfgrass Science
• /
• v.25 no.2
• /
• pp.184-189
• /
• 2011

To optimize tissue culture conditions for genetic transformation of Zoysia matrella (L.) Merr., we investigated the effects of different plant growth regulators and medium supplements on plant regeneration using stolon explants excised from mature plant grown in a green house. Plant regeneration frequency was 33.3% when stolon tissues with a node were cultured on the regeneration medium supplemented with 0.5 mg/L 2,4-D and 1 mg/L of kinetin. Comparing the basal media tested, MS medium showed higher plant regeneration performance than N6 or SH medium. Addition of 5 mg/L $AgNO_3$ with 10 mg/L cysteine improved frequency of plant regeneration up to 40%. Among different carbon sources, 3% sucrose was found to show the best for regeneration frequency. This rapid and efficient plant regeneration system would be useful for using genetic transformation experiments of manilagrass without intervening callus-mediated regeneration.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.12
• /
• pp.4205-4209
• /
• 2011

The $Li_2Mn_{0.5}Fe_{0.5}SiO_4$ silicate was prepared by blending of $Li_2MnSiO_4$ and $Li_2FeSiO_4$ precursors with same molar ratio. The one of the silicates of $Li_2FeSiO_4$ is known as high capacitive up to ~330 mAh/g due to 2 mole electron exchange, and the other of $Li_2FeSiO_4$ has identical structure with $Li_2MnSiO_4$ and shows stable cycle with less capacity of ~170 mAh/g. The major drawback of silicate family is low electronic conductivity (3 orders of magnitude lower than $LiFePO_4$). To overcome this disadvantage, carbon composite of the silicate compound was prepared by sucrose mixing with silicate precursors and heat-treated in reducing atmosphere. The crystal structure and physical morphology of $Li_2Mn_{0.5}Fe_{0.5}SiO_4$ was investigated by X-ray diffraction, scanning electron microscopy, and high resolution transmission electron microscopy. The $Li_2Mn_{0.5}Fe_{0.5}SiO_4$/C nanocomposite has a maximum discharge capacity of 200 mAh/g, and 63% of its discharge capacity is retained after the tenth cycles. We have realized that more than 1 mole of electrons are exchanged in $Li_2Mn_{0.5}Fe_{0.5}SiO_4$. We have observed that $Li_2Mn_{0.5}Fe_{0.5}SiO_4$ is unstable structure upon first delithiation with structural collapse. High temperature cell performance result shows high capacity of discharge capacity (244 mAh/g) but it had poor capacity retention (50%) due to the accelerated structural degradation and related reaction.

• Korean Journal of Head & Neck Oncology
• /
• v.18 no.1
• /
• pp.36-40
• /
• 2002

Background and Objectives: To determine if laser endoscopic microsurgery is a reliable and appropriate approach in the treatment of laryngeal carcinomas. Materials and Methods: Retrospective study of 62 patients treated with CO2 laser from June 1988 to November 2000 at Seoul National University Hospital for laryngeal squamous cell carcinoma. All patients were treated with curative intention. Fifty three untreated patients with laryngeal carcinoma (39 glottic and 14 supraglottic carcinoma patients) had primary carbon dioxide laser microsurgery. Nine radiation failure patients were treated. Postoperative radiotheray was done for 17 patients. Neck dissection was performed simultaneously for 4 supraglottic cases with cervical nodal metastasis. Mean follow-up duration was 40 months. Results: In primary laser surgery group, distribution of tumors (American Joint Committee on Cancer, 1997) were 38 cases with Tl, 13 cases with T2, 2 cases with T3. Cure rate was 88.7%(47/53) and local control rate was 92.5%(49/53). Larynx was preserved in 94%(50/53) of patients. The overall 5-year survival rate(Kaplan-Meier) was 81.5%. In radiation failure group, 56% of patients were recurred after laser surgery. Conclusion: Laser surgery could be a better treatment modality for early laryngeal cancers and selected advanced cases. Additional radiation therapy should be considered if resection margin is not satisfactory.

• Korean Journal of Environmental Agriculture
• /
• v.29 no.3
• /
• pp.221-226
• /
• 2010

Swine wastewater contains high amounts of organic matter and nutrients (nitrogen and phosphorus). The biological nitrogen removal can be achieved by nitrification and denitrification processes. Nitrification-denitrification can be performed via nitrite which is called as the short-cut process. This Short-cut process saves up to 25% of oxygen and 40% of external carbon during nitrification and denitrification. In this study, the batch tests were conducted to assess the different parameters for the nitrite sulfur utilizing denitrification, such as alkalinity, temperature, initial nitrite concentration, and dissolved oxygen. The experimental results showed that the nitrite removal efficiency of the reactor was found to be over 95% under the optimum condition ($30^{\circ}C$ and sufficient alkalinity). Autotrophic nitrate denitrification was inhibited at low alkalinity condition showing only 10% removal efficiency, while nitrite denitrification was achieved over 95%. The nitrite removal rates were found similar at both $20^{\circ}C$ and $30^{\circ}C$. In addition, nitrite removal efficiencies were inhibited by increasing oxygen concentration, but sulfate concentration increased due to sulfur oxidation under an aerobic condition. Sulfate production and alkalinity consumption were decreased with nitrite compared those with nitrate.

• Journal of Energy Engineering
• /
• v.25 no.4
• /
• pp.159-169
• /
• 2016

In this study, the effects of MTBE contents as oxygenates in gasoline on exhaust emissions and fuel economy in MPI and GDi vehicles have been investigated. Various oxygen contents have been selected such as 0, 1.0, 2.3 and 2.7 wt%. FTP-75 and HWFET modes as fuel economy test methods which are widely used in Republic of Korea and US were applied to investigate exhaust emissions from the test vehicles. Emissions of CO, NMHC and NOx did not show significant correlation with oxygen contents in gasoline fuels, although having slight difference with these contents. In addition, CO2 emissions were not significantly changed with respect to oxygen content. But in case of warm-up and FTP-75 and HWFET modes including high speed regimes, CO2 emissions showed inverse correlation with oxygen contents. Particulate number concentration was inversely proportional to the oxygen contents, having the minimum value at the condition of 2.3 wt%. In case of fuel economy through carbon balance method, the highest value has been obtained at 2.3 wt% and there was positive correlation with oxygen contents and fuel economy.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.19 no.4
• /
• pp.381-389
• /
• 2009

Confined spaces are inherently dangerous workplace and many fatal and nonfatal accidents have been reported. Even though these accidents occur in various kinds of confined spaces, there has rarely been reported on the health hazard agent, i.e., the types of gases and their concentration ranges. Therefore in this study, we evaluated several toxic and asphyxiating gas concentrations in various confined spaces. We surveyed 57 manholes, 3 sewage treatment plants, 2 yellow radish manufacturing companies and 7 barges to measure the concentrations of oxygen($O_2$), hydrogen sulfide($H_2S$), carbon monoxide(CO), ammonia($NH_3$). Lower Explosion Limits(LEL) and Volatile Organic Compounds (VOCs). Those four types of confined spaces occupies 56% of accidents during last 9 years in Korea. In 57 manholes, the concentration varied according to the types of manholes; rainfall and sewage, and by location; residential and industrial areas. Sewage manhole in industrial area was evaluated as the most hazardous than other types of manhole like rainfall manholes, residential sewage manholes. The highest $H_2S$ concentration and the lowest $O_2$ concentration at sewage manhole in industrial area were 300 ppm, 8.7% respectively. In 3 sewage treatment plants, $H_2S$ and $NH_3$ concentrations were reached up to the 500 ppm and 200 ppm respectively. Two yellow radish manufacturing companies showed the concentrations of 316 ppm, 505.2 ppm, 90 ppm and 15.7% for $H_2S$, CO, VOCs and $O_2$, respectively. Seven barges showed 15.9%~20.9% oxygen concentration. Gas species and concentration ranges varied by the types and location of confined spaces; CO, $H_2S$, $O_2$ could be hazardous in manhole, especially manhole connected to sewage plants. CO, $H_2S$, LEL, $O_2$, $NH_3$ should be controlled in sludge silo and sluge pumping confined spaces in sewage treatment plant. The activity of lifting out radish from the storage tank was evaluated more hazardous rather than the other activities in yellow radish manufacturing industry. The employers must conduct the survey to identify all possible confined spaces in their local workplace prior to performing the tasks. At the national level to reduce the accidents in the confined spaces, we suggest that systemic approach and active education program including possible hazards, standard operation procedures, ventilation plan, and personal protective equipment in confined spaces should be implemented.

• Journal of the Korean Wood Science and Technology
• /
• v.33 no.6 s.134
• /
• pp.63-70
• /
• 2005

The purpose of this study was to investigate how to modify the physical properties of cellulose after thermal treatment. Cellulose was treated between $225^{\circ}C$ and $325^{\circ}C$ for 3 hrs under air flow, and then the thermally treated cellulose was measured to specific surface area, constitute elements, consumption ofacid and base, as well as the adsorption capacity of ethylamine vapor. The higher was the treating temperature from $225^{\circ}C$ to $325^{\circ}C$, the lower was the total yield of cellulose. Elemental analysis revealed that carbon content in thermally treated cellulose was gradually increased in proportion to temperature increment. The amount of acidic functional groups tended to increase up to $300^{\circ}C$, after then to be lowered slightly. In principle, no alkaline functional groups were found in thermally treated cellulose. In case of treatment with $325^{\circ}C$, only a few amount of alkaline functional groups were detectable. Specific surface area of thermally treated cellulose are determined to $1.9m^2/g$, which value can become higher when the treated temperature rises. The thermally treated cellulose at $275^{\circ}C$ shows the highest adsorption capacity of ethylamine at $40^{\circ}C$ for 4 hrs. Solubility of those two celluloses with WPG (Weight Percent Gain) value of 113% and 108%, respectively, was determined to almost 100%. X-ray diffractogram of thermally treated cellulose suggested that the crystalline structure of cellulose began to be destroyed at the temperature of $275^{\circ}C$. As a conclusion, changes of such a physical properties make it possible to weaken inter and/or intra hydrogen bond in crystal region of cellulose macromolecules. When thermally treated cellulose adsorbs ethylamine, it turns to be well soluble to water.

• Asian-Australasian Journal of Animal Sciences
• /
• v.27 no.3
• /
• pp.439-446
• /
• 2014

Many studies on methane ($CH_4$) and nitrous oxide ($N_2O$) emissions from livestock industries have revealed that livestock production directly contributes to greenhouse gas (GHG) emissions through enteric fermentation and manure management, which causes negative impacts on animal environment sustainability. In the present study, three essential values for GHG emission were measured; i.e., i) maximum $CH_4$ producing capacity at mesophilic temperature ($37^{\circ}C$) from anaerobically stored manure in livestock category ($B_{0,KM}$, Korean livestock manure for $B_0$), ii) $EF_{3(s)}$ value representing an emission factor for direct $N_2O$ emissions from manure management system S in the country, kg $N_2O-N$ kg $N^{-1}$, at mesophilic ($37^{\circ}C$) and thermophilic ($55^{\circ}C$) temperatures, and iii) $N_{ex(T)}$ emissions showing annual N excretion for livestock category T, kg N $animal^{-1}$ $yr^{-1}$, from different livestock manure. Static incubation with and without aeration was performed to obtain the $N_2O$ and $CH_4$ emissions from each sample, respectively. Chemical compositions of pre- and post- incubated manure were analyzed. Contents of total solids (% TS) and volatile solid (% VS), and the ratio of carbon to nitrogen (C/N) decrease significantly in all the samples by C-containing biogas generation, whereas moisture content (%) and pH increased after incubation. A big difference of total nitrogen content was not observed in pre- and post-incubation during $CH_4$ and $N_2O$ emissions. $CH_4$ emissions (g $CH_4$ kg VS-1) from all the three manures (sows, layers and Korean cattle) were different and high C/N ratio resulted in high $CH_4$ emission. Similarly, $N_2O$ emission was found to be affected by % VS, pH, and temperature. The $B_{0,KM}$ values for sows, layers, and Korean cattle obtained at $37^{\circ}C$ are 0.0579, 0.0006, and 0.0828 $m^3$ $CH_4$ kg $VS^{-1}$, respectively, which are much less than the default values in IPCC guideline (GL) except the value from Korean cattle. For sows and Korean cattle, $N_{ex(T)}$ values of 7.67 and 28.19 kg N $yr^{-1}$, respectively, are 2.5 fold less than those values in IPCC GL as well. However, $N_{ex(T)}$ value of layers 0.63 kg N $yr^{-1}$ is very similar to the default value of 0.6 kg N $yr^{-1}$ in IPCC GLs for National greenhouse gas inventories for countries such as South Korea/Asia. The $EF_{3(s)}$ value obtained at $37^{\circ}C$ and $55^{\circ}C$ were found to be far less than the default value.