• 제목/요약/키워드: low-mass

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치과내원환자의 성격특성에 따른 고객충성도 및 구전효과 연구 (A Study on Customer Loyalty and Word-of-Mouth Effect according to Character Trait of Patient in Dental Clinics)

  • 양해영
    • 한국산학기술학회논문지
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    • 제12권12호
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    • pp.5819-5826
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    • 2011
  • 최근 치과 의료계는 장기화된 경기침체와 인력 공급 증가 및 의료기관의 양적 팽창, 의료소비자의 권리의식 향상과 의료소비 욕구의 다양화에 기인하여 의료산업의 경쟁이 심화되고 있다. 이로 인한 치과 의료기관 경영의 어려움은 치과 의료기관의 경쟁력 확보를 위한 노력을 요구하고 있다. 따라서 적은 비용으로 높은 마케팅 효과를 창출하는 구전 마케팅을 매스커뮤니케이션 마케팅의 새로운 대안으로 적극 활용해야할 필요가 있다. 이에 본 연구는 치과내원환자의 성격특성에 따른 고객충성도 및 구전효과 연구를 통해 치과 의료마케팅활동의 표적 집단을 정확히 파악하고 구전촉진요소를 제시함으로써 실무적 관점의 구전 마케팅 전략방안의 기초자료를 제시하고자 한다. 이를 위해 대구 소재 10개 치과의원을 대상으로 2011년 4월 11일부터 5월 6일 까지 4주 동안 설문을 통해 612부의 최종 분석 자료를 얻었다. 분석 결과는 다음과 같다. 대상자의 성격 특성에 따른 고객충성도 차이는 내 외 성향에서는 유의한 차이가 없었으며 마켓 메이븐 성향이 높게 나타난 대상자에게서 높은 고객충성도를 보였다(F=5.243, p=.006). 성격 특성에 따른 구전 효과 차이는 외향형의 대상자($x^2$=6.738, p=.006)와 마켓 메이븐 성향이 높은 대상자($x^2$=17.251, p=.000)에게서 더 많은 구전 경험 차이를 나타냈다. 본 연구 결과는 치과내원환자의 성격 특성에 따른 고객충성도 및 구전효과의 차별적 영향력을 밝히고 있으며 이를 통해 치과의료 마케팅 전략 수립에 있어 고려해야할 실무적 관점의 전략 수립 방안을 제시한 근거자료가 될 것이라 사료된다.

PREPARATION OF AMORPHOUS CARBON NITRIDE FILMS AND DLC FILMS BY SHIELDED ARC ION PLATING AND THEIR TRIBOLOGICAL PROPERTIES

  • Takai, Osamu
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2000년도 추계학술발표회 초록집
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    • pp.3-4
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    • 2000
  • Many researchers are interested in the synthesis and characterization of carbon nitride and diamond-like carbon (DLq because they show excellent mechanical properties such as low friction and high wear resistance and excellent electrical properties such as controllable electical resistivity and good field electron emission. We have deposited amorphous carbon nitride (a-C:N) thin films and DLC thin films by shielded arc ion plating (SAIP) and evaluated the structural and tribological properties. The application of appropriate negative bias on substrates is effective to increase the film hardness and wear resistance. This paper reports on the deposition and tribological OLC films in relation to the substrate bias voltage (Vs). films are compared with those of the OLC films. A high purity sintered graphite target was mounted on a cathode as a carbon source. Nitrogen or argon was introduced into a deposition chamber through each mass flow controller. After the initiation of an arc plasma at 60 A and 1 Pa, the target surface was heated and evaporated by the plasma. Carbon atoms and clusters evaporated from the target were ionized partially and reacted with activated nitrogen species, and a carbon nitride film was deposited onto a Si (100) substrate when we used nitrogen as a reactant gas. The surface of the growing film also reacted with activated nitrogen species. Carbon macropartic1es (0.1 -100 maicro-m) evaporated from the target at the same time were not ionized and did not react fully with nitrogen species. These macroparticles interfered with the formation of the carbon nitride film. Therefore we set a shielding plate made of stainless steel between the target and the substrate to trap the macropartic1es. This shielding method is very effective to prepare smooth a-CN films. We, therefore, call this method "shielded arc ion plating (SAIP)". For the deposition of DLC films we used argon instead of nitrogen. Films of about 150 nm in thickness were deposited onto Si substrates. Their structures, chemical compositions and chemical bonding states were analyzed by using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and infrared spectroscopy. Hardness of the films was measured with a nanointender interfaced with an atomic force microscope (AFM). A Berkovich-type diamond tip whose radius was less than 100 nm was used for the measurement. A force-displacement curve of each film was measured at a peak load force of 250 maicro-N. Load, hold and unload times for each indentation were 2.5, 0 and 2.5 s, respectively. Hardness of each film was determined from five force-displacement curves. Wear resistance of the films was analyzed as follows. First, each film surface was scanned with the diamond tip at a constant load force of 20 maicro-N. The tip scanning was repeated 30 times in a 1 urn-square region with 512 lines at a scanning rate of 2 um/ s. After this tip-scanning, the film surface was observed in the AFM mode at a constant force of 5 maicro-N with the same Berkovich-type tip. The hardness of a-CN films was less dependent on Vs. The hardness of the film deposited at Vs=O V in a nitrogen plasma was about 10 GPa and almost similar to that of Si. It slightly increased to 12 - 15 GPa when a bias voltage of -100 - -500 V was applied to the substrate with showing its maximum at Vs=-300 V. The film deposited at Vs=O V was least wear resistant which was consistent with its lowest hardness. The biased films became more wear resistant. Particularly the film deposited at Vs=-300 V showed remarkable wear resistance. Its wear depth was too shallow to be measured with AFM. On the other hand, the DLC film, deposited at Vs=-l00 V in an argon plasma, whose hardness was 35 GPa was obviously worn under the same wear test conditions. The a-C:N films show higher wear resistance than DLC films and are useful for wear resistant coatings on various mechanical and electronic parts.nic parts.

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배양액과 산소농도가 돼지난포란의 체외성숙과 배발달에 미치는 영향 (Effects of Different Media and Oxygen Concentrations on In Vitro Maturation and Development of Porcine Follicular Oocytes)

  • 천행수;한만희;김종화;박병권;이규승;서길웅
    • Reproductive and Developmental Biology
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    • 제28권2호
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    • pp.119-126
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    • 2004
  • 본 실험은 돼지체외수정란을 생산하는데 적합한 배양액과 산소조건을 구명하기 위하여 NCSU(North Carolina State University)-23, PZM(Porcine Zygotes Medium)-3, PZM-4 및 TCM(Tissue Culture Medium)-199 배양액과 5% 산소조건(39, 5% $O_2$, 5% $CO_2$ , 90% $N_2$ 및 포화습도) 및 20% 산소조건(39, 5% $CO_2$ 및 포화습도)에서 돼지 미성숙난포란의 체외성숙과 체외배발달을 실시하였다. 본 연구에서 얻어진 결과를 요약하면 다음과 같다. 1) 돼지 난포란을 5 및 20% 산소조건하에서 NCSU-23, PZM-3, PZM-4 및 TCM-199 배양액에 44시간 동안 성숙을 유도한 결과 난핵포붕괴율과 핵성숙률에 있어서 산소조건 및 배양액간 유의적(p>0.05)차이는 없었다. 2) 체외수정을 실시한 결과 정자 침투율, 자ㆍ웅전핵형성률, 다정자 침입률 및 평균정자수에 있어서 산소조건 및 배양액간에 유의적인 차이가 없었다. 3) 체외수정을 실시한 후, 5 및 20% 산소조건의 NCSU-23, PZM-3, PZM-4 및 TCM-199 배양액에서 배양하여 배발달에 미치는 영향을 조사한 결과, 난할률에 있어서는 유의적(p<0.05)인 차이가 없었으며. 배발달 7일째 배반포기 발달률에 있어서 5% 산소조건에서는 PZM-3 배양액이, 20% 산소조건에서는 NCSU-23 배양액이 유의적(p<0.05)으로 높은 결과를 나타냈다. 4) 배발달 7일째 배반포기 배의 세포수를 조사한 결과, 내부세포괴세포수와 총세포수는 산소조건과 배양액간에 통계적인 유의성이 인정되지는 않았으나, 5% 산소조건에서 PZM-3 배양액(36.8$\pm$6.5개)이 다소 높은 총세포수를 나타냈다. 위의 결과를 종합하면 돼지체외수정란의 생산에는 5% 산소조건에서 PZM-3 배양액에서 배발달을 유도하는 것이 배반포기 발달률과 세포수에 있어 효과적이라고 판단된다.

B형간염(型肝炎) 표면항원(表面抗原)의 주면역원(主免疫原) 결정기(決定基)에 특이(特異)한 합성(合成) Peptide의 면역원성(免疫原性)에 관한 연구(硏究) (Immunogenicity of Synthetic Peptide Specific for Major Immunogenic Determinat of Hepatitis B Surface Antigen)

  • 신광순;한수남
    • 대한수의학회지
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    • 제25권1호
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    • pp.7-17
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    • 1985
  • Many investigators have been pursuing various attempts so far to produce hepatitis B surface antigen(HBsAg) vaccines using the techniques such as isolation from plasma of chronic HBsAg carrier, recombinant DNA technique or preparation of synthetic peptides specific for immunogenic determinants. Hepatitis B virus can not grow on any cell lines by the tissue culture technique at the present time. The plasma of chronic HBsAg carrier is expensive and its source is limited. The HBsAg from the recombinant DNA technique gave still very low yield. Another approach, therefore, has been initiated to develop a synthetic hepatitis B virus vaccine. The possible use of several distinct synthetic vaccines in prophylaxis can be facilitated by availability of full synthetic immunogens. Peptides synthesized for potential application as antiviral vaccines have been mostly tested in the form of conjugates with carrier proteins, although the free synthetic peptide can be immunogenic. To understand basic knowledges on the antigenicity and immunogenicity of a synthetic peptide specific for major immunogenic determinant of HBsAg, a nonapeptide, $H_2N^{139}Cys-Thr-Lys-Pro-Thr-Asp-Gly-^{146}Asn-Aba$ COOH, which corresponds to HBsAg amino acid residues 139 to 147, was synthesized by the Merrifield's solid-phase method with a slight modification. The antigenicity and immunogenicity of this specific synthetic peptide were examined comparing with purified plasma-derived natural HBsAg. The results obtained are as follows; 1. The peptide synthesized showed the identical amino acid composition to the theoretical value. The degree of purification and molecular weight were acertained by methods of high performance liquid chromatography and mass spectrometry. 2. Using m-maleimidobenzoyl-N-hydroxysuccinimide ester as a conjugating agent, the synthetic peptide was conjugated to rabbit albumin and ${\gamma}$-globulin, tetanus and diphtheria toxoids, and keyhole limpet hemocyanin. Their conjugation yields were 8.3, 9.5, 15.8, 13.5, and 11.2%, respectively. 3. The natural HBsAg was purified from plasma of chronic HBsAg carrier. By the electron microscopic observation of the purified natural HBsAg preparation, no Dane particles were observed and the preparation showed negative DNA polymerase activity. 4. Antigenicity of the synthetic peptide and the plasma-derived natural HBsAg was determined by competition radioimmunoassay using $^{125}I$-natural HBsAg. Their 50% inhibitions appeared as $90{\mu}g/ml$ and $0.12{\mu}g/ml$ for the synthetic peptide and the natural HBsAg, respectively. This indicates that the former was about 750-fold less antigenic than the latter. 5. Immunogenicity of the synthetic peptide was determined by administering the peptide-carrier conjugates into rabbits with and without Freund's complete adjuvant. Regardless the carrier proteins and adjuvant, positive immune responses to the synthetic peptide were observed. The higher antibody titers, however, were shown in the groups administered with Freund's complete adjuvant. 6. Immunizing dose 50% in mice of the various peptide-carrier conjugates was 5.47, 6.00, 65.16, 31.25 and $13.03{\mu}g/dose$ for rabbit albumin and ${\gamma}$-globulin, tetanus and diphtheria toxoids, and keyhole limpet hemocyanin, respectively, while the natural HBsAg showed $0.65{\mu}g/dose$. 7. It was postulated that homologous proteins prefer to heterologous ones as the carriers.

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국내 유통 폴리락타이드(PLA) 식품용 기구 및 용기·포장의 중금속 이행량 모니터링 (Monitoring of Heavy Metals Migrated from Polylactide (PLA) Food Contact Materials in Korea)

  • 김현욱;박소연;조예은;박용춘;박세종;김미혜
    • 한국식품위생안전성학회지
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    • 제33권2호
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    • pp.102-109
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    • 2018
  • 폴리락타이드 재질의 식품용 기구 및 용기 포장에서 식품으로 이행될 우려가 있는 유해 중금속인 납, 카드뮴 및 비소의 이행량을 측정하고 안전성을 평가하기 위하여 국내에 유통중인 폴리락타이드 시료 총 211건을 수거하였다. 용출실험은 '식품용 기구 및 용기 포장 공전'의 조건에 따라 식품모사용매인 4% acetic acid로 하였으며 온도조건으로 $70^{\circ}C$와 가혹사용조건인 $100^{\circ}C$ 모두 적용하여 이행량을 비교하였다. 납, 카드뮴 및 비소의 이행량은 모두 $70^{\circ}C$보다 $100^{\circ}C$의 조건에서 증가하는 경향을 보였으나, 납의 최대 이행량은 기준 규격과 비교하여 1.0%의 낮은 수준이었고, 카드뮴은 모두 미량이 검출되었으며, 비소의 최대 이행량은 기준 규격 대비 3.9%의 낮은 수준으로 기준 규격을 초과하는 시료는 없었다. 이행량 결과를 바탕으로 납, 카드뮴 및 비소의 일일추정섭취량을 산출한 후 잠정주간섭취허용량 등과 비교하는 안전성평가를 진행하였으며, 국내에 유통되는 식품용 폴리락타이드 기구 및 용기 포장을 통한 납, 카드뮴 및 비소의 일일추정섭취량은 $2.5{\times}10^{-5}{\sim}2.0{\times}10^{-3}{\mu}g/kg\;bw/day$인 것으로 산출되었다. 용출조건별로는 $70^{\circ}C$, 30분에서 카드뮴의 일일추정섭취량이 가장 낮았고, $100^{\circ}C$, 30분에서의 납 일일추정섭취량이 $2.0{\times}10^{-3}{\mu}g/kg\;bw/day$로 제일 높게 나타났으나, 납의 위해도는 인체안전기준($25{\mu}g/kg\;bw/week$)과 비교시 0.055% 수준으로 매우 낮음을 확인되었다. 이를 통하여 국내 유통 폴리락타이드 재질 식품용 기구 및 용기 포장에서의 납, 카드뮴 및 비소의 이행량은 매우 낮은 수준임을 확인하였고, 본 연구의 결과는 향후 식품용 기구 및 용기 포장의 안전관리를 위한 과학적인 근거자료로 활용될 수 있을 것으로 사료된다.

대추의 과육지질(果肉脂質)에 존재(存在)하는 지방산(脂肪酸)의 동정(同定)과 숙성(熟成)에 따른 그 조성(組成)의 변화(變化) (Identification of Fatty Acids in the Pulp Oils of Jujube and Their Compsitional Changes in the Ripening Period)

  • 우효경;김성진;박성혜;조용계
    • 한국응용과학기술학회지
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    • 제18권1호
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    • pp.67-77
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    • 2001
  • In search for several fatty acid with unusual structure in vegetable oils, we have found that unknown peaks were shown on GLC in the analysis of fatty acids of the lipids from the pulp of ripened jujube (Zizypus jujuba var. inermis) fruits. These fatty acids were identified as a series of cis-monoenoic acids with ${\omega}-5$ double bond system such as $C_{14:1{\omega}5}$, $C_{16:1{\omega}5}$ and $C_{18:1{\omega}5}$, including ${\omega}-7$ fatty acid as $C_{16:1{\omega}7}$ and $C_{18:1{\omega}7}$, by GLC, solid-phase extraction silver ion-column chromatographic, GLC-mass spectrometric and IR techniques. First of all, total fatty acid methyl esters were resolved into saturated and branched fatty acid, monoenoic acid, dienoic acid, and trienoic acid fraction, respectively, with 100% dichloromethane (DCM), DCM/acetone (9:1, v/v) 100% acetone, and acetone/ acetonitrile (97:3, v/v) solvent system. Unknown fatty acids were included in the monoenoic fraction and were confirmed to have cis-configuration by IR. Picolinyl esters of monoenoic fatty acids gave distinct molecular ion peak and dominant diagnostic peaks, for example, m/z 317, 220 and 260 fragment for $cis-C_{14:1{\omega}5}$, m/z 345, m/z 248 and 288 fragment for $cis-C_{16:1{\omega}5}$ and m/z 373, m/z 276 and 316 fragment for $cis-C_{18:1{\omega}5}$. In this way the occurrence of $cis-C_{16:1{\omega}7}$ and $cis-C_{18:1{\omega}7}$ could be deduced from the appearance of prominent fragments as m/z 345, 220 and 260, and m/z 373, 248 and 280. Level of total ${\omega}-5$ fatty acids amounted to about 30% in the fatty acid composition with the predominance of $C_{16:1{\omega}5}$ $ (18.7{\sim}25.0%)$, in the semi-ripened and/or ripened samples collected in September 14 ($C_{16:1{\omega}5}$ ; 18.7%, $C_{14:1{\omega}5}$ ; 3.6% and $C_{18:1{\omega}5}$ ; 3.0%), September 22 ($C_{16:1{\omega}5}$ ; 25.0%, $C_{14:1{\omega}5}$ ; 1.4% and $C_{18:1{\omega}5}$ ; 2.6%), and October $7 (C_{16:1{\omega}5}$ ; 24.7%, $C_{14:1{\omega}5}$ ; 7.7% and $C_{18:1{\omega}5}$ ; 2.5%). However, the lipids extracted from unripened jujube in July and August contain these unusual fatty acids as low as negligible. It could be observed that the level of ${\omega}-5$ fatty acids in the pulps increased sharply with an elapse of ripening time of jujube fruits. Other monoenoic fatty acids with ${\omega}-7$ series, $C_{16:1{\omega}7}$ (palmitoleic acid) and $C_{18:1{\omega}7}$ (cis-vaccenic acid) could be detected. And in the lipids of the kernel and leaf of jujube, none of ${\omega}-5$ fatty acids could be detected.

A research on the introducing the waterproof corrugated cardboard box for the efficient shipment of chinese cabbages and radishes: Focusing on Garak-dong wholesale market as the center

  • Lee, Rae-Hyup;Sun, Il-Suck
    • Asian Journal of Business Environment
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    • 제2권1호
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    • pp.25-34
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    • 2012
  • It is possible to use pallet for forwarding as chinese cabbages and radishes are general large-scale trading items at the agricultural wholesale market though, however, most of these are forwarded as it have packed in net bags or in P·E bags. Thus, it is still hard for palletizing. The type of packing the product in the net bag makes it difficult for palletizing. It is not a stable shape enough and easily collapsed for pallet loading. Because of this collapsibility, the corrugated cardboard box is being used to enhance forwarding efficiency, but the existing corrugated cardboard box could be crushed easily by moist what is from the agricultural product's property and it also could be squashed by the mass of the loaded box layers on itself. In contrary, the functional waterproof corrugated cardboard box is not collapsed through palletizing and it is efficient for product management with it's ventilation function in respond to pre-cooling effect. Furthermore, because it has various functional shapes as the open type, the partition type and so on, it is effective for maintaining freshness of the product and standardizing the distribution of agricultural product. It is well-known that it is possible to introduce this box to cargo-works of agricultural product. Consequently, the recognition of main distributors about the pallet distribution of the chinese cabbage and the radish was apprehended in this study for activating mechanization of loading and unloading. The survey was conducted to the main distributors such as the forwarder, the auction dealer and the commission merchant with Garak-dong wholesale market as the center. The appropriate packing materials and problems of the existing method for loading and unloading were derived through the survey. Especially, it was focused on analyzing the difference of recognition between the subject groups for the way of using waterproof cardboard corrugated box to deal with the difficult product for packing in normal corrugated box because of the box's absorption of moist from the agricultural product like a chinese cabbage and a radish. Total In the cases of the forwarders and the commission merchants, the net was highly responded as 45%, 74% from each groups for the best packing material for mechanization of distribution and the waterproof corrugated cardboard box was responded as 20%, 22% from each groups as much preferable than multi-stage wooden box. However, for the radish, the waterproof corrugated cardboard box was the best material as 56%, and the auction trader group supported it for 80%. So, the using the waterproof corrugated cardboard box for mechanization of distribution was negative for the chinese cabbage, but it was positive for the radish. The average was 2.42, the standard deviation was 1.24. The negative response(about 55%) was prevailing more than positive response(about 23%). It could be analyzed that even there was the positive recognition for using the waterproof corrugated cardboard box for the radish though the preference for low price of net bag in the chinese cabbage forwarding procedure. Still now, it seems that is a burden for using the waterproof corrugated cardboard box with high price. In the analysis on the recognition differences about using the waterproof corrugated cardboard box for the chinese cabbages and the radish between the forwarders and the commission merchants, generally the negative recognition was prevailing, but the forwarders(2.696) were more positive for using the waterproof corrugated cardboard box than the commission merchants(2.145).

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경기지역 일부 대학생에서 나트륨의 주요 기여 음식과 변이 음식 (Major Dishes Contributing Absolute and Between-Person Sodium Intake Variations in University Students in Gyeonggi-do)

  • 정은정;유하정;심유진
    • 한국식품영양과학회지
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    • 제45권3호
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    • pp.409-419
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    • 2016
  • 본 연구에서는 경기지역 대학생 228명(남 71명, 여 157명)을 대상으로 음식빈도조사지(DFQ-125)를 이용하여 나트륨 섭취량을 조사하고 음식(군)별 나트륨 섭취량, 나트륨의 급원 및 변이 음식을 분석하였다. 남학생은 식사와 함께 섭취하는 국류(P<0.05), 어패류 반찬(P<0.05), 고기류(P<0.05), 콩류(P<0.05)에서 여학생보다 더 많은 나트륨을 섭취하고 있었다. 나트륨의 급원 음식 1, 2위는 남녀 모두 배추김치와 라면류였고 찌개/탕류 중에는 김치찌개가 급원 음식 순위 1위로 동일하였으나, 남학생은 라면으로부터 섭취하는 나트륨의 양이 상대적으로 높았고 여학생은 남학생과 달리 스낵 과자가 급원 음식 중 5위로 높은 순위에 속하였다. 또한 급원 음식 20위 내에 국 종류가 속하지 않은 여학생과 달리 남학생에서는 고염군이 좋아하는 음식으로 알려진 국, 볶음이나 튀김음식이 포함되어 있었다. 남녀 모두에서 고염군은 저염군보다 김치류 및 김치를 이용한 음식, 국물음식 및 자반고등어 조림으로부터 많은 나트륨을 섭취하고 있었다. 개인의 나트륨 섭취량에 큰 영향을 주는 음식인 변이 음식의 종류와 순위는 남녀 간 큰 차이가 있었는데, 남학생의 경우 갈비탕> 생선(참치)통조림> 라면류> 순대+쌈장 순이었고 여학생의 경우 순대+소금> 닭볶음탕>, 된장찌개> 배추김치> 피자 순으로 나타났다. 특히 변이 음식 1위는 남학생에서 갈비탕, 여학생에서 순대+소금이었는데 이들은 모두 기호에 따라 식탁에서 소금을 추가하는 음식으로, 대국민 저염 교육의 효과를 높이기 위해서는 이미 간이 맞춰진 음식에 소금을 더 첨가하지 않도록 하는 실천지침이 포함되어야 할 것이다. 한편, 남학생은 여학생보다 총나트륨 섭취량, 체질량지수, 수축기혈압이 모두 높았으며 음료수류 섭취량(P<0.01)은 물론 음료수로부터 얻는 나트륨의 양도 많은 것으로 나타나(P<0.01) 성별에 따라 나트륨 섭취량 및 음료수 섭취량과 혈압, 비만 간의 상호 관련성을 밝히는 후속 연구가 필요할 것이다. 추가로 효과적인 나트륨 저감 전략을 위해서는 나트륨과 혈압 간의 상관관계 연구로 대상자별 급원 음식뿐 아니라 변이 음식에 대한 조사가 수행되어야 할 것으로 사료된다.

공기조화, 냉동 분야의 최근 연구 동향 -2002년 및 2003년 학회지 논문에 대한 종합적 고찰 - (Recent Progress in Air Conditioning and Refrigeration Research - A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2002 and 2003 -)

  • 정광섭;김민수;김용찬;박경근;박병윤;조금남
    • 설비공학논문집
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    • 제16권12호
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    • pp.1234-1268
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    • 2004
  • A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2002 and 2003 has been carried out. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment/design. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation in diverse facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat transfer, humidity was also interesting to promote comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing research topics. Well developed CFD technologies were widely applied for analysis and design of various facilities and their systems. (2) Heat transfer characteristics of enhanced finned tube heat exchangers and heat sinks were extensively investigated. Experimental studies on the boiling heat transfer, vortex generators, fluidized bed heat exchangers, and frosting and defrosting characteristics were also conducted. In addition, the numerical simulations on various heat exchangers were performed and reported to show heat transfer characteristics and performance of the heat exchanger. (3) A review of the recent studies shows that the performance analysis of heat pump have been made by various simulations and experiments. Progresses have been made specifically on the multi-type heat pump systems and other heat pump systems in which exhaust energy is utilized. The performance characteristics of heat pipe have been studied numerically and experimentally, which proves the validity of the developed simulation programs. The effect of various factors on the heat pipe performance has also been examined. Studies of the ice storage system have been focused on the operational characteristics of the system and on the basics of thermal storage materials. Researches into the phase change have been carried out steadily. Several papers deal with the cycle analysis of a few thermodynamic systems which are very useful in the field of air-conditioning and refrigeration. (4) Recent studies on refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement when new alternative refrigerants are applied. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and new alternative refrigerants including natural refrigerants. Efficiency of various compressors and performance of new expansion devices are also dealt with for better design of refrigeration/air conditioning system. In addition to the studies related with thermophysical properties of refrigerant mixtures, studies on new refrigerants are also carried out. It should be noted that the researches on two-phase flow are constantly carried out. (5) A review of the recent studies on absorption refrigeration system indicates that heat and mass transfer enhancement is the key factor in improving the system performance. Various experiments have been carried out and diverse simulation models have been presented. Study on the small scale absorption refrigeration system draws a new attention. Cooling tower was also the research object in the respect of enhancement its efficiency, and performance analysis and optimization was carried out. (6) Based on a review of recent studies on indoor thermal environment and building service systems, it is noticed that research issues have mainly focused on several innovative systems such as personal environmental modules, air-barrier type perimeterless system with UFAC, radiant floor cooling system, etc. New approaches are highlighted for improving indoor environmental conditions and minimizing energy consumption, various activities of building energy management and cost-benefit analysis for economic evaluation.

9 ~ 11세 아동의 불포화지방산, n-3 지방산 및 n-6 지방산의 섭취와 아토피 피부염 과의 관련성 : 2013 ~ 2015년 국민건강영양조사 (Relation of polyunsaturated fatty acid, n-3 fatty acid and n-6 fatty acid intakes and atopic dermatitis in the 9~ 11 year old children: KNHANES 2013 ~ 2015)

  • 김지명
    • Journal of Nutrition and Health
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    • 제52권1호
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    • pp.47-57
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    • 2019
  • 본 연구는 제6기 (2013 ~ 2015년) 국민건강영양조사 자료를 이용하여 만 9 ~ 11세의 학령기 아동 752명을 대상으로 아토피 피부염 유병에 따른 지방산 섭취상태 및 지방산 섭취가 아토피 피부염 위험에 미치는 영향을 분석하였다. 국내 만 9 ~ 11세 아동의 아토피 피부염 유병율은 17.69% 이었고, 아토피 피부염 아동의 연령이 10.20세로 정상 아동의 10.01세보다 유의적으로 높았다. 그러나, 체위상태를 살펴보았을 때, 아토피 피부염 아동의 신장, 체중, BMI 모두 정상 아동보다 유의적으로 낮게 나타났다. 월 가구 소득수준은 아토피 피부염 아동에서 중하> 상> 중상> 하의 순으로 나타난 반면, 정상 아동은 중상> 상> 중하> 하 순으로 차이를 보였다. 국내 9 ~ 11세의 아토피 피부염 아동은 정상 아동에 비해 탄수화물의 에너지섭취비율이 유의적으로 높고, 지질의 에너지섭취비율, 다가불포화지방산, n-3 지방산, n-6 지방산의 섭취상태가 유의적으로 낮았다. 또한, 리놀레산, 감마 리놀레산, 리놀렌산 섭취량도 아토피 피부염 아동에서 정상 아동에 비해 유의적으로 낮았다. 연령, 성별, 체질량지수 및 소득수준을 보정하였을 때에도 동일한 결과를 보였다. 그러나 P/S 비율 및 n-6/n-3 비율은 아토피 피부염 아동과 정상 아동 간에 유의적인 차이를 보이지 않았다. 9 ~ 11세 아동의 총 지방 및 단일불포화지방산 섭취에서 가장 기여도가 높은 식품은 돼지고기로 전체 섭취량의 12.97%, 17.47%였다. 포화지방산 섭취에 기여도가 가장 높은 식품은 우유로, 전체 섭취량의 18.24%였다. 콩기름은 다가불포화지방산, n-3 지방산 및 n-6 지방산 섭취에서 기여도가 가장 높은 식품으로, 전체 섭취량의 23.79%, 25.24%, 24.07%였다. 아토피 피부염 아동에서는 다가불포화지방산 및 n-6 지방산 급원식품으로 정상아동과 달리 닭고기가 상위 10개 식품에 포함되었고, 참기름의 섭취량이 높았다. n-3 지방산 급원식품으로 고등어 섭취량이 아토피 피부염 아동에서 높았다. 국내 9 ~ 11세 아동에서 지방산 섭취가 아토피 피부염 위험도에 미치는 영향은 보정 여부에 상관없이 탄수화물의 에너지섭취비율은 아토피 피부염 위험도를 유의적으로 높이는 반면, 지질의 에너지섭취비율, 다가불포화지방산, n-3 지방산, n-6 지방산의 섭취가 아토피 피부염 위험도를 유의적으로 낮추는 것으로 나타났다. 이상을 종합해 볼 때, 학령기 아동의 아토피 피부염 위험도에 탄수화물 및 지질의 에너지섭취비율, 불포화지방산, n-6 지방산 및 n-3 지방산의 섭취량 등이 영향을 미치는 것으로 보이나, 아토피 피부염 아동에서 보여 지는 고탄수화물 저 지질식은 증상 개선을 위한 식이조절의 결과일 수 있어, 결과해석에 주의가 필요하다. 식이 조절 시, 적절한 지방산 섭취비율의 균형을 고려하여 섭취하는 것이 도움이 될 것으로 사료되며, 이와 관련하여 아토피 피부염 개선을 위한 지방산의 적정 비율에 관한 추가 연구가 필요할 것으로 보인다.