• Proceedings of the Korean Vacuum Society Conference
• /
• 2000.02a
• /
• pp.91-91
• /
• 2000

a-C:H 혹은 a-SiC:H 박막은 광전소자 및 태양전지 등의 개발에 있어서 중요한 물질이다. 우리는 a-C:H 및 a-SiC:H 박막을 PECVD (plasma-enhanced chemical vapor deposition) 방법으로 증착시키고, 박막의 가열에 따른 스핀밀도의 변화를 ESR (electron spin resonance) 측정을 통하여 조사하였다. PECVD 증착가스는 Ch4, SiH4 가스를 사용하였고, 기판은 Corning 1737glass를 사용하였으며, 기판 온도는 300-40$0^{\circ}C$, 증착 압력은 0.1-0.3 Torr, r.f. 전력은 3-36W 사이에서 변화되었다. ESR 측정은 상온 X-band 영역에서 수행되었고, modulation amplitude는 2.5G, modulation frequency는 100kHz 이었다. a-C:H 혹은 a-SiC:H 박막은 진공상태의 reactor, 혹은 공기중의 furnace 안에서 300-50$0^{\circ}C$ 영역에서 3-8시간 정도 가열되거나, 혹은 상온에서 약 50$0^{\circ}C$ 정도까지 단계적으로 가열되었다. 증착된 a-C:H 박막의 초기 구조는 Raman 측정으로부터 polymer-like Carbon으로 추정되었으며, 300-35$0^{\circ}C$ 가열시 초기 1시간 정도 사이에는 스핀밀도가 증가되었으나, 그 후 8시간 정도까지의 가열의 경우에도 대체로 동일하게 나타났다. 또한 상온으로부터 약 50$0^{\circ}C$까지 단계적으로 온도를 높여주며, 각 단계마다 1시간씩 가열했을 때도 30$0^{\circ}C$ 정도까지는 스핀밀도가 증가하다가 더 높은 온도로 가면서 다시 스핀밀도가 감소함을 볼 수 있었다. 이러한 스핀밀도의 초기 증가 및 감소를 일으키는 메카니즘에 대해서 논의해 볼 것이다.

• Journal of Food Hygiene and Safety
• /
• v.24 no.1
• /
• pp.12-18
• /
• 2009

This experiment was conducted to investigate the effect of wa-song (Orostachys japonicus A. Berger) extracts on the oxidative stability of edible oil. Wa-song was dried from hot air (HWE) and freeze (FWE), and then they were extracted by hot water. The different levels (0.1, 0.5 and 1.0 g/100 mL) of HWE and FWE were added to soybean oil and lard. The chromaticity of edible oils was generally increased with prolonged heating time and HWE was higher than FWE. The anisidine value showed significant increase during heating for 48hrs. After heating for 48 hrs, it was lower than control, except for HWE added sample of 0.5 and 1.0 g/100 mL, FWE added sample of 1.0 g/100 mL. In lard, it was lower in sample added wa-song extract than control. The acid value was not significant by added amount of wa-song. Its value in HWE added sample was lower than FWE, after heating for 48 hrs. POV was lower HWE than FWE, also. After heating for 24 hrs, TBA values in soybean oil containing HWE and FWE added sample was lower than control. In lard, its value in HWE and FWE added sample was lower than control during heating for $12{sim}48\;hrs$. Therefore, those results suggested that HWE has higher antioxidant activity than FWE added sample, and then oxidative stability of HWE in edible oil was more potential for lard during its heating.

• Journal of Energy Engineering
• /
• v.25 no.4
• /
• pp.103-109
• /
• 2016

Polyethylene pipes has useful benefits which are anti-corrosive and flexible material, so it is used to gas pipes but also class 3 water pipes of nuclear power plant, process pipes of petrochemical plant and chemical plant. So the usage of polyethylene pipes is widely increased. But it has been limited for the usage of polyethylene, because it can not be directly detected to fusion joints by using non destructive evaluation. Polyethylene pipes are connected by two methods, one is butt fusion and the other is electrofusion. Butt fusion is widely used to connecting the pipes. It is proposed to method for determining the reliability of joints in this study that is detection of the melt flow zone at fusion joints. In this study, middle density polyethylene is used, outside diameter of the test specimen is 225mm and thickness is 20.5mm. Speed of ultrasonic of this test specimen is 2,200m/s. Test specimens were fabricated by varying the heating time which means from 0% to 130% applying time through heating plate to polyethylene for detecting melt flow zone. Also 4 additional test specimens were made, one was made that not scrapping attached surface of pipes but applying 100% of the proper heating time and the others were made to include of soil, gravel and vinly tape paper at fusion joints, that were also applied 100% of proper heating time. Ultrasonic testing to measure the melt flow zone of 20 test specimens was conducted by using 3.5MHz and 5.0MHz ultrasonic probes and melt flow zone measuring was conducted to three times at different point to one specimen. To differentiate the melt flow zone signal, post image processing was equally conducted to all test results and image levels, contrast, sharpen, threshold were adopted to all teat results and the test results were displayed gray scale. From the results, for the shorter heating times the reflection area of multiple echo have been increased, so the data was obtained from the position where it can be eliminated as much as possible. At 80% of proper heating time(168 sec.), the signal of melt flow zone was obtained clearly, so measuring could be conducted. From 7% of proper heating time(15 sec.) to shorter heating times. we could not obtain the signal because test specimen was not fused. From the result, we can verify that measuring of melt flow zone by using phased array ultrasonic imaging method is possible. And we can verify to complete and incomplete butt fusion by measuring the melt flow zone.

• Korean journal of food and cookery science
• /
• v.30 no.6
• /
• pp.670-678
• /
• 2014

The purpose of this study was to find the optimal swelling method and condition for seacucumber to improve its taste and texture to accomodate the rapid increase of consumption. Another purpose was to try to determine an easy way to soak dried sea-cucumber under different conditions, and identify the influence of swelling time on the texture of sea-cucumber, in order to reduce preparation time and provide basic data for easy handling. After boiling or steaming for six different periods including 5, 15, 30 and 60 minutes the texture of the sea-cucumbers were compared, For the additive test, the sea-cucumbers were boiling for 30 minutes period with 4 different additives and the textures were compared, Since the texture is an important characteristic of sea-cucumber, there are many variables that affect this property including the, drying and preservation methods. This study provides basic understanding of the influence of the heating method, time and temperature on the swelling of sea-cucumber for handy use at processing sites.

• Korean journal of food and cookery science
• /
• v.15 no.5
• /
• pp.490-499
• /
• 1999

The purpose of this study was to investigate the changes of taste components in the boiled beef brisket soup stock and shank soup stock by varying pretreatment, boiling temperature and time. Free amino acids and nucleotides color and sensory evaluation in each samples were analyzed. The results were obtained as follows : 1. The amount of free amino acids in the brisket soup stock pretreated by soaking and blanching showed a tendency to increase in proportion to boiling time. The amount of glutamic acid in the brisket soup stock was much in order of soaking > blanching > roasting pretreatment. While the amount of glutamic acid in the boiled soup stock samples pretreated by soaking and blanching was much more at low temperature than at high temperature, the glutamic acid contents in the boiled soup stock pretreated by roasting were large at high temperature. The amount of glutamic acid in pretreated by soaked soup stock showed the highest and recorded 8.73 mg% at 6 hour-low temperature-boiling. 2. The amount of free amino acids in the shank soup stock did not show any regular tendency and had few changes in quantity by the methods of pretreatment. Each amount of glutamic acid in the shank soup stock pretreated by soaking and blanching was the highest, when boiled for 3 hours at high temperature. The samples pretreated by roasting showed the highest record 2.49 mg%, when boiled for 6 hours at high temperature, but could not recognize any regular tendency in the case of boiling at low temperature. 3. The amount of nucleotides in the brisket soup stock generally showed increase in proportion to boiling time. The amount of 5'-IMP extracted from the brisket soup stock was much in order of blanching > soaking > roaking pretreatment, but few differences between blanching and soaking soup stock samples. The amount of 5'-IMP extracted from soup stock samples pretreated by soaking and blanching was high at low-boiling and by roasting at high-boiling. Each amount of 5'-IMP extracted from soup stocks pretreated by soaking(BSL) and blanching(BBL) was the highest at 6 hour-low-boiling(37.06 mg%), and 5 hours(38.37 mg%) respectively. The amount of 5'in the soup stock pretreated by roasting(BRH) showed the highest records at 6 hour-high-boiling(10.85 mg%). 4. The amount of 5'-IMP extracted from the shank soup stock preteated by soaking and blanching showed a tendency to decrease after 3 hours boiling irrelative of boiling temperature. The amount of 5'in the shank soup stock was much in order of soaking > blanching > roasting pretreatment and showed high at the boiling of high temperature. In the sample pretreated by roasting it showed the highst records when boiled for 6 hours at high temperature(1.55 mg%). 5. The L Value of the brisket soup stock pretreared by roasting at high temperature(BRH) was the lowest and the b value of it was the highest of all the brisket samples boiled for 6 hours. No differences were found in the Value of L, a, and b in shank soup stock by the methods of pretreatment and boiling temperature. 6. The sensory scores in color and flavor of the brisket soup stock showd that BRH was higher than the other samples, and the preference in taste and overall was the highest in BSH while it was the lowest in BRH. The preference in the all sensory characteristics of SSH was higher than any other shank soup stock, but did not show any significant difference statistically.

• Journal of Food Hygiene and Safety
• /
• v.24 no.3
• /
• pp.204-210
• /
• 2009

Antioxidative activities of fresh, steamed and black garlics by different processing condition were investigated on the soybean oil. The crushed fresh, steamed and black garlics were added to 100 mL of soybean oil at a level of 0, 5, 10,20 and 40 g respectively, and then the oil mixture containing garlics (reaction samples) were heat-treated for 48 hrs at $180^{\circ}C$. The chromaticity of reaction samples were increased during heating. After 48 hrs heating, in the sample added 40 g/ 100 mL chromaticity of each samples were 1.36, 2.99 and 1.99, in the crushed fresh, steamed and black garlics, respectively. Anisidin value showed irregularly increased during heating. Acid values of reaction samples were higher than control during heating, those levels were ranged from 0.82 to 2.04 mg/g after 12 hrs, were gradually increased to $3.15{\sim}4.30\;mg$/g after 48 hrs. Peroxide value of reaction sample containing black garlic(40 g/ 100 mL) was lower than the samples containing tocopherol or BHT, after 48 hrs heating. TBA value of reaction samples containing fresh, steamed and black garlic of 40 g/ 100 mL were the lowest in the sample added black garlic, after 48 hrs heating. These results suggested that oxidative stability of black garlic in soybean oil was more potential than the other garlics during heating.

• Korean Journal of Food Science and Technology
• /
• v.41 no.4
• /
• pp.355-361
• /
• 2009

Polycyclic aromatic hydrocarbons (PAHs) are environmental carcinogenic compounds that arise by several means including food processing methods such as smoking and direct drying and cooking. This study examined the concentration of PAHs in sesame oils with various roasting temperatures (190, 220 and $250^{\circ}C$), methods (direct heating vs. indirect hot air heating), and times (5, 10, 15, 20 and 25 min). The PAHs in the sesame oils were analyzed using liquid-liquid extraction and solid-phase clean up (Florisil), followed by HPLC with fluorescence detection. According to the results, mean levels of total PAHs increased when the sesame oils were roasted at increasing temperatures and times. The sesame oil roasted at $250^{\circ}C$ for 25 min had the highest mean value of total PAHs (4.66 ${\mu}g$/kg). The results of this study suggest that the indirect hot air roasting method decreased PAH formation during sesame oil processing.

• Applied Chemistry for Engineering
• /
• v.9 no.6
• /
• pp.884-888
• /
• 1998

Effects of heating time under high temperature on the thermal and mechanical properties of neutron shielding materials based on modified (KNS-102), hydrogenated(KNS-106) bisphenol-A type epoxy resin and phenol-novolac(KNS-611) type epoxy resin for radioactive material shipping casks have been investigated. At early stages, the initial decomposition temperatures of the shielding materials of KNS-102, KNS-106 and KNS-611 increased with the heating time under high temperature, but it was rarely affected by the heating time in the later stages. In addition, the thermal conductivities of KNS-102 and KNS-106 decreased with heating time, but that of KNS-611 increased with the heating time. On the contrary, the thermal expansion coefficients of neutron shielding materials decreased with increase of heating time. At the high temperature, the tensile strength and flexural strength of the shielding materials of KNS-102 and KNS-611 increased with heating time, but those of KNS-106 decreased with increase of heating time. And the heating time under high temperature on the neutron shielding materials did not show measurable loss of weight and hydrogen content.

• Korean Journal of Food Science and Technology
• /
• v.26 no.1
• /
• pp.26-30
• /
• 1994

The purpose of this study was to investigate the effects of heating times of soy protein isolate(SPI) and mixing ratio of coagulants mixture on water holding capacity(WHC) and oil absorption capacity (OAC) of SPI, texture properties and yield of tofu. The effect of heating at $100^{\circ}C$ on the amounts of coagulants required for coagulation showed that the amounts of $CaCl_{2},\;MgCl_{2}$ and GDL decreased as the heating time extended to $6{\sim}9$ minutes while $CaSO_{2}$ was changed little. The tofu yield showed maximum for the tofu prepared by 6 minutes boiling and coagulation with $CaSO_{4}$. The WHC of SPI was significantly reduced by heating at $100^{\circ}C$ while OAC was rather increased until 9 minutes of heating. The textural properties of SPI tofu coagulated with mixed coagulants$(CaSO_{4}-GDL,\;CaSO_{4}-CaCl_{2},\;CaCl_2-GDL)$ showed that softer tofu was obtained as the ratio of $CaSO_{2}$ increased and harder tofu as the ratio of $CaCl_{2}$ and GDL increased. The maximum and minimum tofu yields were prepared from 100% of $CaSO_{2}$ and 100% of GDL, respectively. Organoleptic properties showed that more uniform and tender tofu were obtained with higher portion of $CaSO_{2}$ in the mixed coagulants and higher intensity of sourness and bitterness were scored as the GDL and $CaCl_{2}$ added more.

• Korean journal of food and cookery science
• /
• v.9 no.1
• /
• pp.52-56
• /
• 1993

This study was examined on the change of mineral contents (Calcium, Potassium, Magnesium Zinc, Iron, Sodium, Phosphorus) in Sam-gye-tang broth cooked by various cooker and boiling time. The results were as follows; 1) In cauldron, the contents of Calcium, Potassium, Magnesium Zinc Iron Sodium, Phosphorus were increased in proportion to boiling time. In pressure cooker, the contents of Calcium, Potassium, Magnesium, Zinc are increased according to boiling time but the contents of Iron, Sodium, Phosphorus were showed the maxium value at 120 minutes and were decreased since then. 2) Ca/P was 1:0.91 in raw materials of Sam-gye-tang. But the extracting rate of Ca/P of the broth cooked in cauldron was 1:3.58∼1:4.68 and 1:2.02∼l:3.96 in pressure cooker. This rate was quite different from the recommended one of 1:1∼l:1.5. 3) In the increasing rate of minerals according to boiling time, the increasing rate of Calcium was showed similar in cauldron and pressure cooker, but Potassium, Magnesium, Sodium, Phosphorus were showed the maximum increasing rate from 30 to 60 minutes in cauldron and pressue cooker. Zinc was showed the maximum increasing rate from 120 to 150 minutes in cauldron and from 30 to 60 minutes in pressure cooker.