• Title/Summary/Keyword: low temperature

Search Result 17,552, Processing Time 0.063 seconds

Comparative Analysis of GNSS Precipitable Water Vapor and Meteorological Factors (GNSS 가강수량과 기상인자의 상호 연관성 분석)

  • Jae Sup, Kim;Tae-Suk, Bae
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.33 no.4
    • /
    • pp.317-324
    • /
    • 2015
  • GNSS was firstly proposed for application in weather forecasting in the mid-1980s. It has continued to demonstrate the practical uses in GNSS meteorology, and other relevant researches are currently being conducted. Precipitable Water Vapor (PWV), calculated based on the GNSS signal delays due to the troposphere of the Earth, represents the amount of the water vapor in the atmosphere, and it is therefore widely used in the analysis of various weather phenomena such as monitoring of weather conditions and climate change detection. In this study we calculated the PWV through the meteorological information from an Automatic Weather Station (AWS) as well as GNSS data processing of a Continuously Operating Reference Station (CORS) in order to analyze the heavy snowfall of the Ulsan area in early 2014. Song’s model was adopted for the weighted mean temperature model (Tm), which is the most important parameter in the calculation of PWV. The study period is a total of 56 days (February 2013 and 2014). The average PWV of February 2014 was determined to be 11.29 mm, which is 11.34% lower than that of the heavy snowfall period. The average PWV of February 2013 was determined to be 10.34 mm, which is 8.41% lower than that of not the heavy snowfall period. In addition, certain meteorological factors obtained from AWS were compared as well, resulting in a very low correlation of 0.29 with the saturated vapor pressure calculated using the empirical formula of Magnus. The behavioral pattern of PWV has a tendency to change depending on the precipitation type, specifically, snow or rain. It was identified that the PWV showed a sudden increase and a subsequent rapid drop about 6.5 hours before precipitation. It can be concluded that the pattern analysis of GNSS PWV is an effective method to analyze the precursor phenomenon of precipitation.

Studies on the Improvement and Utilization of Pasture in the Foerst II. The effect of shde on the intake palptability and grazing behavior (임간초지의 개량 및 이용에 관한 연구 II. 채식기호성 및 방목습성에 미치는 비음의 영향)

  • 이인덕;윤익석;이조윤;신용국
    • Journal of The Korean Society of Grassland and Forage Science
    • /
    • v.5 no.3
    • /
    • pp.207-211
    • /
    • 1985
  • This study was conducted to determine the effects of shade (full day light; 100, 80, 60, 40 and 20%) and fertilization levels (high; $N\;30kg-P_2O_5\;35kg-K_2O\;30kg$, moderate; $N\;20kg-P_2O_5\;25kg-K_2O\;20kg$, and low; $N\;10kg-P_2O_5\;15kg-K_2O\;10kg$) of forest pasture on intake palatability of Korean native goat, and the effects of shade under the conditions of 50% shaded forest pasture and full day light pastures on grazing behavior. This experiment was done at the experimental field of Chungnam National University, in Taejon, from 1983 to 1984. The results obtained are summarized as follows: 1. The dry matter intake, R.I.I. and Touch number of Korean native goat were affected by the shade degrees and fertilization levels, generally the increase of the fertilization level and high shading degree increased the NO_3-N$ contents in the plants, but decreased the soluble carbohydrate contents. It means that the decrease of the utilization of the shade culture grasses is due to the decreased intake palatability of forest pastures, particularly the conditions high fertilization level and above 60% of shading level seemed to have a nitrate stress. 2. Grazing time of forest pastures by Korean native goat tended to be spend more time than full day light pastures, also tendency of the major grazing activity tended to be graze continuously without difference of variation of grazing time within a day. Considering of the characteristies os shade, the intensive utilization of forest pastures seemed to be most effective during the high temperature season in August.

  • PDF

Quality Characteristics and Granule Manufacture of Mulberry and Blueberry Fruit Extracts (오디 및 블루베리 추출물을 이용한 과립제조 및 품질특성)

  • Park, Hye-Mi;Yang, Su-Jin;Kang, Eun-Ji;Lee, Dae-Hoon;Kim, Dae-Ik;Hong, Joo-Heon
    • Korean journal of food and cookery science
    • /
    • v.28 no.4
    • /
    • pp.375-382
    • /
    • 2012
  • The quality characteristics of granules prepared from water and 50% ethanol extracts of mulberry and blueberry were investigated. The total polyphenol and total flavonoid contents of mulberry and blueberry were higher in the 50% ethanol extract than those in the water extract. Total anthocyanin content was highest in the 50% mulberry ethanol extract (470.91 mg/100 g). Oxygen radical absorbance capacity (ORAC) of the mulberry and blueberry extracts was 335.37 ${\mu}moles\;TE/g$ and 238.14 ${\mu}moles\;TE/g$, respectively. Superoxide radical scavenging activity of the mulberry and blueberry extracts increased with an increase in extract concentration. Total polyphenol and flavonoid contents of granules from the mulberry extract were 4.83 mg/mL and 3.49 mg/mL, respectively. Total anthocyanin content of granules from the mulberry and blueberry extracts was 76.26 mg/100 g and 75.26 mg/100 g, respectively. Electron donating ability and ORAC of granules from the mulberry and blueberry extracts were 45.09% and 24.10%, 87.65 ${\mu}moles\;TE/g$ and 57.59 ${\mu}moles\;TE/g$, respectively. Granules that were stored for 7 weeks at room temperature had low anthocyanin content degradation and Hunter color values (L, a, and b).

Changes of Quality Characteristics on the Bread added Chitosan (키토산 첨가에 따른 식빵의 품질 변화)

  • Lee, Hyun-Young;Kim, Seong-Mi;Kim, Jin-Young;Youn, Sun-Kyoung;Choi, Jung-Su;Park, Sun-Mee;Ahn, Dong-Hyun
    • Korean Journal of Food Science and Technology
    • /
    • v.34 no.3
    • /
    • pp.449-453
    • /
    • 2002
  • This was studied to evaluate the quality characteristics of the bread added chitosan during storage at room temperature(Temp. $27^{\circ}C{\pm}2$, RH $75%{\pm}10$). The volume of the dough was increased depending on the larger molecular weight and the higer concentration of chitosan but was decreased at 0.50% of 120 kDa chitosan. The water activity was low depending on the larger molecular weight and the higher concentration of chitosan at the early storage, but maintained constantly during storage totally. The colors of the bread was hardly affected by 30 kDa of chitosan. Textural characteristics was improved at 30 kDa and 120 kDa of chitosan. Especially, the change of the hardness were maintained lower at 30 kDa, 120 kDa of chitosan during storage than that of standard. These results showed that the quality of the bread by added 30 kDa of chitosan was improved highly.

Effects of Additives on Quality Attributes of Minced Ginger During Refrigerated Storage (첨가물이 냉장 중 생강 다대기의 품질특성에 미치는 영향)

  • Choi, Min-Seek;Kim, Dong-Ho;Lee, Kyung-Hae;Lee, Young-Chun
    • Korean Journal of Food Science and Technology
    • /
    • v.34 no.6
    • /
    • pp.1048-1056
    • /
    • 2002
  • Quality of fresh ginger deteriorates rapidly during low temperature storage, and its storage life is short due to sprouting and microbial spoilage. The objectives of this research were to develop, using additives, a minced ginger product, which could maintain acceptable quality for over 30 days, and to investigate its quality changes during the cold storage. Storage stability of minced ginger product was investigated from the standpoint of the inhibition of brown discoloration, gas formation and liquid-solid separation. Fresh ginger was peeled and ground to produce minced ginger (control). Sodium bisulfite, L-cysteine, NaCl, sodium benzoate, modified starch, and/or xanthan gum were added to the control to minimize quality loss during storage, and to develop an optimum formula (A) of minced ginger. Samples were packed in Nylon/PE films, stored at $5^{\circ}C$, sampled at a 30-day interval, and subjected to quality evaluations. Changes in pH, surface color, gas formation, liquid-solid separation, contents of free amino acids, free sugars, organic acids, and fatty acids were determined. Gas formation was effectively inhibited in samples with sodium benzoate and/or NaCl. Samples with xanthan gum did not result in liquid-solid separation. L-Cysteine and sodium bisulfite were effective in controlling discoloration. pH decreased during storage in all samples, except sample A. Organic acid contents of all samples increased during storage, with lactic acid content showing the highest increase. Free amino acid content decreased with increasing storage time. Free sugar content of all samples decreased during storage. Sensory results showed sample A maintained acceptable quality until 90 days of storage. These results suggest that quality of minced ginger could be successfully maintained with the additions of selected additives for up to 90 days.

Quality Attributes of Whole Soybean flour Tofu Affected by Coagulant and Theirs Concentration (응고제 종류와 농도에 따른 전지대두분 두부의 품질)

  • Kim, Ju-Young;Kim, Jun-Han;Kim, Jong-Kuk;Moon, Kwang-Deog
    • Korean Journal of Food Science and Technology
    • /
    • v.32 no.2
    • /
    • pp.402-409
    • /
    • 2000
  • To investigate the textural and physical characteristics of WSF(whole soybean flour) tofu affected by coagulant and its concentration, $CaCl_2$, $CaSO_4$, $GDL(glucono-{\delta}\;lactone)$, $MgCl_2$, and some mixed coagulants were used in this study. Yields of WSF tofu coagulated with $CaSO_4$ and GDL were ranged 4.3-4.5(g/g WSF), but common tofu was 2.2-3.0(g/g soybean). As the water addition ratio increased, L and a value were increased while heating time increased, b value increased. L value of WSF tofu was lower and b value was higher than conventional tofu and 4 commercial tofus. Kinds of coagulant and its concentration significantly affected to textural properties of WSF tofu. As the concentration of coagulant increase, the hardness increased in most all coagulants. WSF tofu coagulated with $CaSO_4$ and GDL recorded low hardness and adhesiveness, and high springiness among the used coagulants at the same concentration. As the hardness increased, the gumminess and chewiness increased in most all coagulants. As coagulation temperature and molding pressure increase, hardness also increased. WSF tofu coagulated with 0.3% $CaSO_4+GDL$ was the most similar in the textural properties with conventional tofu and 4 commercial tofus. WSF tofu coagulated with 0.3% of $CaSO_4+GDL$ at $85^{\circ}C$, 10 times water addition, 5min. heating and $25.0g/cm^2$ molding pressure recorded the highest score in the sensory evaluation.

  • PDF

A Study on the menu preferences with school dinner by food service management types in Daegu (대구지역 고등학생의 학교급식 공급유형에 따른 석식식단 선호도 조사)

  • Lee, Eun-Ju
    • Journal of Nutrition and Health
    • /
    • v.45 no.5
    • /
    • pp.489-499
    • /
    • 2012
  • The purpose of this study is to present basic data for an improvement of school foodservice by identifying students' preference level for school meal menu. A survey was carried out in two high schools provided with different types of consignment service in Daegu. Study subjects were consisted of 100 high school students from a school with on-site service and 119 students from the other school with external transporting service. More than half of students (54.2% of male and 68.3% of female) had normal weights while 13.5% of male and 30.1% of female students had underweights. 'Taste' and 'family' were the most important factors in meal choices and in eating habits, respectively of all the study subjects. Students who answered to have unbalanced diet (33.0%) were less in school with on-site service than those (56.1%) with external transporting service. Compared with on-site service, preferences for meats fruit and milk were higher and as cooking method, preference for blanching lower but stew, roasting and frying higher in the school with external transporting service. Various types of cooking methods and food materials were better accepted by the students with on-site service than those with external transporting service who preferred meat more exclusively regardless of cooking methods of main dish. Most kinds of kimchi was less liked by the students with external transporting service. It is concluded that low preference for most menus provided by the external transporting service is attributed by limitation in food materials, cooking methods and maintenance of food temperature. The limitation could be overcome by more intensive efforts for developing menus and using more efficient facilities and ultimately by changing meal service system in cooperation with school administrators, dietitians and parents.

Isolation, Purification and Some Properties of Polyphenol Oxidase from Pear (배과실(果實)의 Polyphenol Oxidase의 분리(分離) 정제(精製) 및 그 특성(特性))

  • Kang, Yoon Han;Sohn, Tae Hwa;Choi, Jong Uck
    • Current Research on Agriculture and Life Sciences
    • /
    • v.4
    • /
    • pp.55-64
    • /
    • 1986
  • Polyphenol oxidase in japanese pear (Pyrus communis var. mansamkil) was isolated, partially purified and its some properties were investigated. Polyacrylamide disc gel electrophoresis indicated two bands with polyphenol oxidase activity in the extract from acetone dry powder of par flesh. These two polyphenol oxidases (PPO A and PPO B) were purified through acetone precipitation and diethylaminoethyl cellulose column chromatography. PPO A and B were purified 7.8 fold and 8.7 fold by the present procedure, respectively. The Rm values of partially purified PPO A and B were estimated to be 0.58 and 0.68, respectively. The optimum temp, and pH of PPO A activity were $33^{\circ}C$ and pH 7.0, while those of PPO B were $30^{\circ}C$ and pH 4.2, respectively. Two PPO were unstable over the temperature of $60^{\circ}C$. The substrate specificity of pear PPO showed high affinity toward o-diphenolic compounds, especially catechol in PPO A and chlorogenic acid in PPO B, but inactive toward m-diphenol, p-diphenol and monophenols. PPO A showed affinity toward the trihydroxyphenolic compound. $Zn^{{+}{+}}$ activated the PPO A activity but $Fe^{{+}{+}}$ inhibited PPO B activity, while $Fe^{{+}{+}}$ and $Zn^{{+}{+}}$ activated the PPO B activity, while $Fe^{{+}{+}}$ and $Zn^{{+}{+}}$ activated the PPO B activity but $K^+$, $Mg^{{+}{+}}$, $Ca^{{+}{+}}$ and $Hg^{{+}{+}}$ inhibited at 10mM concentration. $Cu^{{+}{+}}$ activated the enzyme action at low concentrations but inhibited at high concentration. Inhibition studies indicated that L-ascorbic acid, L-cysteine and thiourea were most potent. The Km values of PPO A and PPO B for catechol were 20mM and 14.3mM, respectively.

  • PDF

Naked Waxy Barley Cultivar "Jinjuchal" with High Whiteness after Cooking and High β-glucan Content (취반 후 백도가 좋고 베타글루칸 함량이 높은 찰성 쌀보리 "진주찰")

  • Lee, Mi-Ja;Seo, Jae-Hwan;Kim, Yang-Kil;Park, Jong-Chul;Choi, Jae-Seong;Park, Tae-Il;Hyun, Jong-Nae;Kim, Jung-Gon
    • Korean Journal of Breeding Science
    • /
    • v.41 no.3
    • /
    • pp.299-305
    • /
    • 2009
  • A new six-rowed naked barley cultivar "Jinjuchal" with high whiteness after cooking and high $\beta$-glucan content was developed from the cross between 'Jinmichapssalbori' with high winter hardiness, lodging tolerance, grain whiteness and pearling yield, and 'Suwon 333' with waxy endosperm by the Honam Agricultural Research Institute (HARI), NICS, RDA in 2007. An elite line, SB962002G-B-B-B-84-4 was selected in 2002 and designated as 'Iksan 79' It showed good agronomic performance in the regional yield trials (RYT) from 2005 to 2007 and was released with the name of "Jinjuchal" possessing high whiteness and low proanthocyanidin waxy endosperm. The average heading and maturing dates of "Jinjuchal" were April 27 and June 1 in paddy field, which were same and one day later than those of the check cultivar 'Saechalssalbori' respectively. The new cultivar, "Jinjuchal" had 81 cm of culm length that was 1cm longer than that of 'Saechalssalbori' and 4.9 cm of spike length. It showed 673 spikes per $m^2$, 56 grains per spike, 27.0 g of 1,000-grain weight, and 752 g of test weight. "Jinjuchal" showed stronger hardiness and better resistance to powdery mildew and BaYMV (Barley yellow mosaic virus) than those of the check cultivar, 'Saechalssalbori' It showed higher $\beta$-glucan content(8.4%) and water absorption rate than those of the check cultivar, 'Saechalssalbori' Its average yield of the pearled grain in the regional yield trial was 3.79 MT/ha in upland, and 3.73 MT/ha in paddy field, which were 1% lower and 3% higher than those of the check cultivar, respectively. Total phenol and proanthocyanidin contents were 4.2 and 0.2 mg/g, respectively. This cultivar is suitable for the area of the daily minimum temperature above $-6^{\circ}C$ in January in Korean peninsula.

Improvement of Energy Density in Supercapacitor by Ion Doping Control for Energy Storage System (에너지 저장장치용 슈퍼커패시터 이온 도핑 제어를 통한 에너지 밀도 향상 연구)

  • Park, Byung-jun;Yoo, SeonMi;Yang, SeongEun;Han, SangChul;No, TaeMoo;Lee, Young Hee;Han, YoungHee
    • KEPCO Journal on Electric Power and Energy
    • /
    • v.5 no.3
    • /
    • pp.209-213
    • /
    • 2019
  • Recently, demand for high energy density and long cycling stability of energy storage system has increased for application using with frequency regulation (F/R) in power grid. Supercapacitor have long lifetime and high charge and discharge rate, it is very adaptable to apply a frequency regulation in power grid. Supercapacitor can complement batteries to reduce the size and installation of batteries. Because their utilization in a system can potentially eliminate the need for short-term frequent replacement as required by batteries, hence, saving the resources invested in the upkeep of the whole system or extension of lifecycle of batteries in the long run of power grid. However, low energy density in supercapacitor is critical weakness to utilization for huge energy storage system of power grid. So, it is still far from being able to replace batteries and struggle in meeting the demand for a high energy density. But, today, LIC (Lithium Ion Capacitor) considered as an attractive structure to improve energy density much more than EDLC (Electric double layer capacitor) because LIC has high voltage range up to 3.8 V. But, many aspects of the electrochemical performance of LIC still need to be examined closely in order to apply for commercial use. In this study, in order to improve the capacitance of LIC related with energy density, we designed new method of pre-doping in anode electrode. The electrode in cathode were fabricated in dry room which has a relative humidity under 0.1% and constant electrode thickness over $100{\mu}m$ was manufactured for stable mechanical strength and anode doping. To minimize of contact resistance, fabricated electrode was conducted hot compression process from room temperature to $65^{\circ}C$. We designed various pre-doping method for LIC structure and analyzing the doping mechanism issues. Finally, we suggest new pre-doping method to improve the capacitance and electrochemical stability for LIC.