• Title/Summary/Keyword: microwave processing

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Novel synthesis of nanocrystalline thin films by design and control of deposition energy and plasma

  • Han, Jeon G.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.77-77
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    • 2016
  • Thin films synthesized by plasma processes have been widely applied in a variety of industrial sectors. The structure control of thin film is one of prime factor in most of these applications. It is well known that the structure of this film is closely associated with plasma parameters and species of plasma which are electrons, ions, radical and neutrals in plasma processes. However the precise control of structure by plasma process is still limited due to inherent complexity, reproducibility and control problems in practical implementation of plasma processing. Therefore the study on the fundamental physical properties that govern the plasmas becomes more crucial for molecular scale control of film structure and corresponding properties for new generation nano scale film materials development and application. The thin films are formed through nucleation and growth stages during thin film depostion. Such stages involve adsorption, surface diffusion, chemical binding and other atomic processes at surfaces. This requires identification, determination and quantification of the surface activity of the species in the plasma. Specifically, the ions and neutrals have kinetic energies ranging from ~ thermal up to tens of eV, which are generated by electron impact of the polyatomic precursor, gas phase reaction, and interactions with the substrate and reactor walls. The present work highlights these aspects for the controlled and low-temperature plasma enhanced chemical vapour disposition (PECVD) of Si-based films like crystalline Si (c-Si), Si-quantum dot, and sputtered crystalline C by the design and control of radicals, plasmas and the deposition energy. Additionally, there is growing demand on the low-temperature deposition process with low hydrogen content by PECVD. The deposition temperature can be reduced significantly by utilizing alternative plasma concepts to lower the reaction activation energy. Evolution in this area continues and has recently produced solutions by increasing the plasma excitation frequency from radio frequency to ultra high frequency (UHF) and in the range of microwave. In this sense, the necessity of dedicated experimental studies, diagnostics and computer modelling of process plasmas to quantify the effect of the unique chemistry and structure of the growing film by radical and plasma control is realized. Different low-temperature PECVD processes using RF, UHF, and RF/UHF hybrid plasmas along with magnetron sputtering plasmas are investigated using numerous diagnostics and film analysis tools. The broad outlook of this work also outlines some of the 'Grand Scientific Challenges' to which significant contributions from plasma nanoscience-related research can be foreseen.

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INVESTIGATION OF BAIKDU-SAN VOLCANO WITH SPACE-BORNE SAR SYSTEM

  • Kim, Duk-Jin;Feng, Lanying;Moon, Wooil-M.
    • Proceedings of the KSRS Conference
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    • 1999.11a
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    • pp.148-153
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    • 1999
  • Baikdu-san was a very active volcano during the Cenozoic era and is believed to be formed in late Cenozoic era. Recently it was also reported that there was a major eruption in or around 1002 A.D. and there are evidences which indicate that it is still an active volcano and a potential volcanic hazard. Remote sensing techniques have been widely used to monitor various natural hazards, including volcanic hazards. However, during an active volcanic eruption, volcanic ash can basically cover the sky and often blocks the solar radiation preventing any use of optical sensors. Synthetic aperture radar(SAR) is an ideal tool to monitor the volcanic activities and lava flows, because the wavelength of the microwave signal is considerably longer that the average volcanic ash particle size. In this study we have utilized several sets of SAR data to evaluate the utility of the space-borne SAR system. The data sets include JERS-1(L-band) SAR, and RADARSAT(C-band) data which included both standard mode and the ScanSAR mode data sets. We also utilized several sets of auxiliary data such as local geological maps and JERS-1 OPS data. The routine preprocessing and image processing steps were applied to these data sets before any attempts of classifying and mapping surface geological features. Although we computed sigma nought ($\sigma$$^{0}$) values far the standard mode RADARSAT data, the utility of sigma nought image was minimal in this study. Application of various types of classification algorithms to identify and map several stages of volcanic flows was not very successful. Although this research is still in progress, the following preliminary conclusions could be made: (1) sigma nought (RADARSAT standard mode data) and DN (JERS-1 SAR and RADARSAT ScanSAR data) have limited usefulness for distinguishing early basalt lava flows from late trachyte flows or later trachyte flows from the old basement granitic rocks around Baikdu-san volcano, (2) surface geological structure features such as several faults and volcanic lava flow channels can easily be identified and mapped, and (3) routine application of unsupervised classification methods cannot be used for mapping any types of surface lava flow patterns.

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Dehydration of Foamed Fish(Sardine)-Starch Paste by Microwave Heating 2. Quality Stability and Shelf-life of the Product (어육(정어러) 발포건조제품가공에 관한 연구 2. 제품저장중의 품질변화와 저장기간)

  • LEE Kang-Ho;LEE Byeong-Ho;SONG Dong-Suck;You Byeong-Jin;LEE Byeong-Ho;SUH Jae-Soo;JEA YOi-Guan;RYU Hong-Soo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.15 no.4
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    • pp.291-297
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    • 1982
  • In this part of the studies on dielectric dehydration of foamed fish-starch paste, qualify stability and shelf-life of the product of which the preparation formula and processing conditions were described in previous report (Lee et al, 1982) were determined by means of accelerated reaction test. The product was stored for 50 days under the conditions of temperatures at 35, 45, and $55^{\circ}C$ in steady state and various water activities of 0.44, 0.52, 0.65, and 0.75, respectively. The loss of available lysine, extent of TBA value, and development of browning during the storage were measured and reaction kinetically analysed to assess quality stability and shelf-life of the product for the storage at room temperature of $25^{\circ}C$. Extent of browning was accelerated with the increase of water activity and temperature marking the time to reach a limit of color and flavor deterioration, or to reach brown color density of 0.17 O.D./g at 420 nm, 106 days at aw=0.44, $35^{\circ}C$, and 41 days at aw=0,65, $55^{\circ}C$, These reaction rates resulted in a prediction of shelf-life, 130 to 110 days in the storage at aw=0.44 to 0.75, $25^{\circ}C$. The quality limit assessed by TBA values and sensory evaluation of rancidity was 87 days at aw=0.44, $35^{\circ}C$, and 30 days at aw=0.75, $55^{\circ}C$ which gave a predicted shelf-life, 128 to 113 days . at aw=0.44 to 0.75, $25^{\circ}C$ storage.

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Mineral Contents in Soybeans with Different Cooking Methods (조리방법에 따른 콩의 무기질 함량)

  • Kim, So Young;Hwang, Jinbong;Park, Ji Su;Choi, Youngmin;Nam, Jin-sik;Lee, Jong-Hun;Seo, Dongwon
    • The Korean Journal of Community Living Science
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    • v.28 no.4
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    • pp.525-535
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    • 2017
  • The purpose of this study was to compare the of ash and minerals contents in different types of soybeans (Baektae, Seoritae, Heuk Tae and Seomoktae) with different cooking methods. Raw, boiled and pan-fried soybean samples were prepared by the Rural Development Administration. Samples were digested by using a microwave and analyzed using ICP-OES and ICP-MS for determining the ash and minerals contents. Ash content in four raw soybeans ranged from 5.07 to 5.59 g/100g. There was no significant difference in the ash contents in raw and pan-fried soybeans (p>0.05). However, the ash content of boiled soybeans was 9 to 14% lower than that of raw soybeans (p<0.05). The minerals contents of Baektae and Seomoktae were high and the major minerals of various soybeans were K, P, Mg, and Ca, which accounted for ash 60.80-65.61%, 20.73-24.26%, 6.90-8.46% and 5.79-8.60%, respectively. The mineral contents of soybeans were significantly different depending on the type of cultivar (p<0.05), but the tendency was not constant. Because the process of soaking and boiling of soybeans made the soluble minerals elute, the ash and mineral contents were reduced. And process of pan-frying of soybeans make Because process of soaking and boiling of soybeans make soluble minerals elute (Ed- this section is very confused and seems to have 2 sentences combined: please check your intended meaning), the ash and mineral contents were reduced. As the soybeans are cooked by pan-frying, the water in the soybeans is evaporated and the mineral content is concentrated or kept constant. These results can serve as the basic data of mineral content during processing and cooking of soybeans.

Impact of Cooking Method on Bioactive Compound Content and Antioxidant Capacity of Cabbage (양배추 가공조건에 따른 생리활성 물질의 함량 및 항산화 활성)

  • Hwang, Eun-Sun;Thi, Nhuan Do
    • Korean Journal of Food Science and Technology
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    • v.47 no.2
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    • pp.184-190
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    • 2015
  • We evaluated the effects of three common cabbage cooking methods (blanching, steaming and microwaving) on glucosinolate and S-methylmethionine (SMM) content and total antioxidant capacity of cabbage leaves. We detected four glucosinolates, including glucoraphanin, sinigrin, glucobrassicin, and 4-methoxyglucobrassicin, by high-pressure liquid chromatography (HPLC). Cabbage contained high levels of SMM (192.85 mg/100 g dry weight), compared to other cruciferous vegetables. Blanching cabbage leaves for one to ten minutes decreased glucosinolate and SMM levels, whereas microwaving or steaming cabbage for 5-10 min preserved glucosinolate and SMM levels. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2-2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activities of cooked cabbage generally decreased as cooking time increased, but microwave cooking had a smaller negative effect on antioxidant activities than blanching or steaming. This study demonstrates that some domestic cooking methods, such as microwaving and steaming, can increase the bioaccessibility of glucosinolates and SMM, highlighting the positive role of cooking on the nutritional qualities of cabbage.

Blind Adaptive Equalization of Partial Response Channels (부분 응답 채널에서의 블라인드 적응 등화 기술에 관한 연구)

  • 이상경;이재천
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.11A
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    • pp.1827-1840
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    • 2001
  • In digital data transmission/storage systems, the compensation for channel distortion is conducted normally using a training sequence that is known a priori to both the sender and receiver. The use of the training sequences results in inefficient utilization of channel bandwidth. Sometimes, it is also impossible to send training sequences such as in the burst-mode communication. As such, a great deal of attention has been given to the approach requiring no training sequences, which has been called the blind equalization technique. On the other hand, to utilize the limited bandwidth effectively, the concept of partial response (PR) signaling has widely been adopted in both the high-speed transmission and high-density recording/playback systems such as digital microwave, digital subscriber loops, hard disk drives, digital VCRs and digital versatile recordable disks and so on. This paper is concerned with blind adaptive equalization of partial response channels whose transfer function zeros are located on the unit circle, thereby causing some problems in performance. Specifically we study how the problems of blind channel equalization associated with the PR channels can be improved. In doing so, we first discuss the existing methods and then propose new structures for blind PR channel equalization. Our structures have been extensively tested by computer simulation and found out to be encouraging in performance. The results seem very promising as well in terms of the implementation complexity compared to the previous approach reported in literature.

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Development of Landslide Detection Algorithm Using Fully Polarimetric ALOS-2 SAR Data (Fully-Polarimetric ALOS-2 자료를 이용한 산사태 탐지 알고리즘 개발)

  • Kim, Minhwa;Cho, KeunHoo;Park, Sang-Eun;Cho, Jae-Hyoung;Moon, Hyoi;Han, Seung-hoon
    • Economic and Environmental Geology
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    • v.52 no.4
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    • pp.313-322
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    • 2019
  • SAR (Synthetic Aperture Radar) remote sensing data is a very useful tool for near-real-time identification of landslide affected areas that can occur over a large area due to heavy rains or typhoons. This study aims to develop an effective algorithm for automatically delineating landslide areas from the polarimetric SAR data acquired after the landslide event. To detect landslides from SAR observations, reduction of the speckle effects in the estimation of polarimetric SAR parameters and the orthorectification of geometric distortions on sloping terrain are essential processing steps. Based on the experimental analysis, it was found that the IDAN filter can provide a better estimation of the polarimetric parameters. In addition, it was appropriate to apply orthorectification process after estimating polarimetric parameters in the slant range domain. Furthermore, it was found that the polarimetric entropy is the most appropriate parameters among various polarimetric parameters. Based on those analyses, we proposed an automatic landslide detection algorithm using the histogram thresholding of the polarimetric parameters with the aid of terrain slope information. The landslide detection algorithm was applied to the ALOS-2 PALSAR-2 data which observed landslide areas in Japan triggered by Typhoon in September 2011. Experimental results showed that the landslide areas were successfully identified by using the proposed algorithm with a detection rate of about 82% and a false alarm rate of about 3%.

The Causes of Guilt in Ready-meal Users: A Focus on Cooking Instructions and Consumers' Health Locus of Control

  • Shin, Hyunsook;Lee, Dongmin;Lim, Jeeyoung;Moon, Junghoon
    • Asia Marketing Journal
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    • v.21 no.4
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    • pp.25-43
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    • 2020
  • Although ready meals have recently increased their market share in the Korean food industry, a literature review found that the use of ready meals triggers feelings of guilt in homemakers. Such guilt arises as a result of several factors apparently related to consumers' health. Consequently, levels of guilt might be expected to vary depending on consumers' perceived health locus. The present study aims to examine (a) how health locus affects guilty feelings about ready-meal consumption, (b) how the effect varies in relation to the consumption of different types of ready meal, and (c) the relationship between consumers' guilty feelings and willingness to buy ready meals. Three dimensions of health locus of control (HLC) -internal HLC (IHLC), powerful-others HLC (PHLC), and chance HLC (CHLC)- were presumed to influence consumers' feelings of guilt in association with ready meals. Data were collected via an online survey, and participants were randomly assigned to either of two groups: one group was instructed to heat meals in a microwave (ready-to-heat [RTH] group, n=104) and the other cooked using a pan with additional ingredients (ready-to-cook [RTC] group, n=101). The study found that guilty feelings about consuming RTH meals increased in line with increased external HLCs, namely, PHLC and CHLC. For the RTC group, guilt increased in line with increased PHLC. IHLC had no significant effect on guilty feelings in either group. Willingness to buy ready meals decreased for both groups as consumers' feelings of guilt increased. Even RTC meals, which require more time and energy in food preparation, did not reduce guilty feelings among consumers with higher PHLC. RTC meals are preferable for consumers with higher CHLC, since their sense of greater involvement in the cooking process alleviates their feelings of guilt. Cooking with already prepared and uncooked ingredients brought fun and joy, both for the participants and their significant others. This interpretation may be developed into a strategic plan by ready-meal producers to strengthen their marketing strategy.

Processing and Property of Olive Flounder Paralichthys olivaceus Steak (넙치(Paralichthys olivaceus)스테이크제품의 제조 및 품질특성)

  • Yoon, Moon-Joo;Kwon, Soon-Jae;Lee, Jae-Dong;Park, Si-Young;Kong, Cheong-Sik;Joo, Jong-Chan;Kim, Jeong-Gyun
    • Journal of Fisheries and Marine Sciences Education
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    • v.27 no.1
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    • pp.98-107
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    • 2015
  • Olive flounder contains rich amount of lysine which is required for children's growth. Moreover, it is good foodstuffs for elderly, convalescent and diabetics because of low lipid content and high digestibility. This study was investigated for the purpose of obtaining basic data which can be applied to the processing of olive flounder steak. Olive flounder 100 g were chopped, mixed with vegetable (onion 20%, celery 10%, carrot 15%, garlic 1% of chopped olive flounder meat) and ingredient (bread crumbs 20 g, onion 15 g, celery 10 g, egg 1 ea, tarragon 1/2 t, blanc sauce 20 g, fresh cream 20 mL, salt and pepper pinch). Mixed dough was molded into steak shape ($12{\times}7cm$) and was processed by two types of products, Steak-1 {Roasting for 2 minutes in a frying pan wrapped with olive oil and then vacuum packaging in polyethylene film ($20{\times}30{\times}0.05mm$), and then storage at $-20^{\circ}C$ for 7 days, next thawed and warmed by microwave for 2 minutes} and Steak-2 {vacuum-packaging in polyethylene film ($20{\times}30{\times}0.05mm$), and then storage at $-20^{\circ}C$ for 7 days, after thawed, roasted during 2 minutes in a frying pan wrapped with olive oil}. The factors such as pH, TBA value, amino-N, free amino acid, chemical composition, color value (L, a, b), texture profile, sensory evaluation and viable bacterial count of the olive flounder steak (Steak-1, Steak-2) were measured. From the result of sensory evaluation, Steak-2 showed a bit more high scores than Steak-1 but it was difficult to distinguish significant difference (color, odor, taste, texture and acceptance) between Steak-1 and Steak-2 products.

Processing of Water Activity Controlled Fish Meat Paste by Dielectric Heating 1. Formulation and Processing Conditions (내부가열을 이용한 보장성어육(고등어) 연제품의 가공 및 제품개발에 관한 연구 1. 원료${\cdot}$첨가물의 배합 및 가공조건)

  • LEE Kang-Ho;LEE Byeong-Ho;You Byeong-Jin;SUH Jae-Soo;JO Jin-Ho;JEONG In-Hak;JEA Yoi-Guan
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.17 no.5
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    • pp.353-360
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    • 1984
  • As an effort to expand the utilization of mackerel which has been thought disadvantageous to processors due to the defects in bloody dark color of meat, high content of lipid, and low stability of protein, and to develope a new type of product, so called, preservative fish meat paste, the processing method was studied in which dielectric heating was applied by means of cooking, pasteurization, dehydration, and control of water activity. The principle of this method is based on that dielectric heating can initiate a rapid dispersion or displacement of moisture in the meat tissue so that the level of water acivity can be controlled by dehydration with hot air meanwhile the product is cooked, pasteurized, and texturized. And the product is finally heated with electric heaters and vacuum sealed to stabilize water activity and storage stability. In present paper, a formula for preparing the fish meat-stach paste, the conditions of dielectric heating and dehydration, shape and size of the product, and other parameters were tested to optimize the process operation. A formula of the fish meat-starch paste to provide proper textural properties and water activity was $10\%$ starch, $1.5\%$ salt, $3\%$ soybean, $0.6\%$ MSG, $2\%$ sucrose, and $3\%$ sorbitol against the weight of fish meat. A proper shape and size of the product to avoid foaming and case hardening during heating was sliced disc of 8 cm $diameter{\times}0.8$ cm thickness or $10{\times}10$ cm square plate with 1.0 cm thickness. The disc shape was recommended because it resulted more uniform heating, minimum foaming and case hardening. And it was also advantageous that disc was simply provided when the fish meat disc was stuffed in the same, solidified in boiling water for 2 to 3 minutes, and sliced. Condition of dielectric heating was critical to decide the levels of sterility, water activity, and textural property of the product. The temperature at the center of the meat disc slices was raised up to $95^{\circ}C$ in 1.5 minutes so that continuous exposure to microwave caused expanded tissue and hardening ending up with a higher water content. Heating for 5 to 6 minutes was adequate to yield the final water activity of 0.86 to 0.83(35 to $40\%$ moisture). It is important, however, that heating had to be done periodically, for instance, in the manner of 2.0, 1.5, 1.5, and 1.0 minute to give enough time to displace or evaporate moisture from the meat tissue. The product was dehydrated for 2 to 3 minutes by hot air of $60^{\circ}C$, 3 to 5m/sec and finally exposed to electric heaters for 5 to 6 minutes until the surface was roasted deep brown. These conditions of heating and dehydration resulted in a complete reduction of total plate count from an initial count of $5.3{\times}10^6/g$ to less than $3{\times}10^2/g$. General composition of the product was $40.1\%$ moisture, $20.8\%$ protein, $17.4\%$ lipid, $16.2\%$ carbohydrate, and $5.5\%$ ash. Textural properties revealed folding test AA, hardness 42, cohesiveness 0.53, toughness 4.6, and elasticity 0.8.

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