• Title/Summary/Keyword: 과포화

Search Result 922, Processing Time 0.025 seconds

Degradation evaluation of paint films on surface treated steel by electrochemical impedance spectroscopy (전기화학적 임피던스 분광법에 의한 표면처리한 강재 도장의 부식-도막 열화도 평가)

  • Park, Jun-Mu;Park, Jae-Hyeok;Kim, Sun-Ho;U, Sang-Gyun;Gwon, Yong-Min;Mun, Gyeong-Man;Lee, Myeong-Hun
    • Proceedings of the Korean Institute of Surface Engineering Conference
    • /
    • 2018.06a
    • /
    • pp.95-95
    • /
    • 2018
  • 강재의 방식법 중 도장은 부식을 억제하는데 효과적이고 편리한 방법으로 선박 및 해양 강 구조물의 방식법으로 사용되고 있다. 한편, 강 구조물의 효율적인 유지관리를 위해서는 방식 도장의 도막 열화도를 평가하고 잔존 수명을 예측하여 최적 시기에 보수도장 혹은 재도장하는 것이 필요하다. 일반적으로 선박 및 해양구조물에 적용되는 도막의 방식 성능 평가 방법으로 해수 침지 시험, 염수 분무 시험, 옥외 폭로 시험 등이 있다. 그러나 이러한 시험들은 그 시험 방법에 따라서 정량적인 평가에 한계가 있음은 물론 장기간 소요되는 등 곤란한 문제점이 있다. 그러므로 선박 및 해양구조물을 비롯하여 교량, 각종 강 구조물의 도장 방식에 사용되는 방식용 도료의 성능을 단기간에 적절하게 평가할 수 있는 가속시험법이 제시되며 연구-사용되고 있다. 그 중 도막 방식 성능을 보다 효율적, 비파괴적, 정량적으로 평가할 수 있는 임피던스 분광법(EIS)과 같은 전기화학적 방법은 상대적으로 시험 기간을 크게 단축시킬 수 있고, 대상 방식 도장의 미세한 성능 차이도 분별 가능하다는 장점이 있다[1]. 따라서 본 연구에서는 선박 및 해양구조물 등 가혹한 부식환경에서 강력한 내구성을 가질 수 있도록 다양한 종류의 표면처리 도장 시편을 제작하여 자외선 조사-염수분무-침지환경 등의 열악한 환경조건 하에서 부식-열화 촉진 시험을 실시하였다. 그리고 그 촉진 열화 과정에서 도막의 외관 상태를 관찰 분석함은 물론 전기화학적 임피던스 분광법을 병행 측정하며 그 표면막의 부식 및 도막 열화도를 비교-종합 평가하였다.본 연구에 사용된 시편은 Al 및 Zn 도금 강판에 에폭시, 에폭시-실리콘 우레탄, 에폭시-우레탄 도장 시편으로 Scribe, No Scribe 및 비교재 Al 및 Zn 도금 시편으로 분류하여 각각 실험을 진행하였다. 즉, 도막 열화 시험은 복합 노화 시험법으로 UV 조사 36 시간(ASTM G53), 염수분무 32 시간(ISO 7253), 수분 응축 10 시간을 1 Cycle로 100 Cycle(7800 시간) 동안 실험을 진행하였다. 이때 도막 열화도 평가는 전기화학적 임피던스 분광법을 이용하여 각 실험 조건별로 주파수에 따른 임피던스(Z) 값을 평가하였다. 즉, 상온 $25^{\circ}C$의 3.5% NaCl 100 ml 수용액에 작동 전극(Working Electrode)과 구리 도선을 통해 연결하였고, 노출 면적은 $1cm^2$로 일정하게 유지 하였으며, 상대 전극(Counter Electrode)은 탄소봉, 기준 전극(Reference Electrode)으로 포화카로멜전극(Saturated Calomel Electrode)을 사용하여 측정하였다. No Scribe 시편의 경우에는 Al 기판 에폭시-실리콘 우레탄 도장 시편이 우수한 도막 저항성을 나타내었으며, 에폭시-우레탄 도장시편은 23사이클 이후의 저항값이 가장 낮게 나타났다. Zn 기판의 경우는 에폭시, 에폭시-실리콘 우레탄, 에폭시-우레탄 도장 시편 모두 저항 값이 유사하였으며, Al 및 Zn 도금 시편은 도장 처리된 시편에 비해 훨씬 낮은 저항 값을 보였다. 또한 Scribe 시편의 경우에는 Al 기판 에폭시-실리콘 우레탄 도장 시편에서 높은 초기 저항 값을 보였으며, 23 사이클 후의 저항 값은 세 종류의 도막에서 약 1~0.1 Gohm 으로 나타났다. 그리고 Zn 기판 에폭시-실리콘 우레탄 도장 시편에서 가장 낮은 도막 저항 값이 나타났다. 이상의 실험을 통해서 본 연구 내용은 실내촉진시험으로 선박 및 해양 강 구조물에 사용되는 다양한 종류의 도막의 열화도를 평가하는 기초 설계 지침으로 응용될 수 있을 것으로 사료된다. 한편, 도막은 노출 환경에 따라 방식 성능이 다르므로 실제 도막의 사용환경을 고려하여 도장 사양별 적용 부위에 따른 적정 가속 실험 방법을 선정할 필요가 있다고 사료된다.

  • PDF

X-linked Adrenoleukodystrophy in Childhood (X 염색체 연관 부신백질이영양증 환아들의 임상양상)

  • Yoo, Eun Jung;Kim, Eun Young;Kook, Hoon;Woo, Young Jong
    • Journal of The Korean Society of Inherited Metabolic disease
    • /
    • v.5 no.1
    • /
    • pp.33-43
    • /
    • 2005
  • Purpose: X-linked adrenoleukodystrophy(ALD) is a rare disorder that shows a great deal of phenotypic variability. We subdivided chidhood X-linked ALD patients into several phenotypes by the age at onset, the sites of most severe clinical involvement and the rate of progression of neurologic symptoms. Methods: Thirteen patients who had been diagnosed as X-linked ALD and followed up for at least one year were enrolled from 1996 to 2003. Results: 1. Ten had childhood cerebral ALD, who showed first neurologic symptoms at 7.02 years and progressed rapidly: interval between first symptoms and vegetative state was 1.35 years, and interval from initial symptoms to death was 3.35 years. Treatment with Lorenzo's oil did not prevent neurologic progression. Two patients who underwent umbilical cord blood transplantation died. 2. Two had adolescent cerebral ALD. They had first symptoms at 11.5 years, and showed tendency to progress less rapidly than childhood cerebral form patients. 3. One "Addison only" patient who had adrenal insufficiency without nervous system involvement remained asymptomatic during Lorenzo's oil treatment. 4. All cerebral form patients except one showed the lesions in both parieto-ocipital white matter in brain magnetic resonance imaging. Conclusion: The cerebral ALD was the most common form in childhood and was asoociated with a serious prognosis.

  • PDF

Development and Food Component Characteristics of Canned Boiled Rainbow Trout (송어 보일드 통조림의 개발 및 식품학적 성분 특성)

  • Kang, Kyung-Tae;Kim, Hyung-Jun;Lee, Take-Sang;Kim, Hye-Suk;Heu, Min-Soo;Hwang, Na-Ae;Ha, Jin-Hwan;Ham, Joon-Sik;Kim, Jin-Soo
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.36 no.8
    • /
    • pp.1015-1021
    • /
    • 2007
  • To expand the use of rainbow trout, the preparation of canned rainbow trout was conducted and the characteristics were also examined. Canned boiled rainbow trout was low in moisture, while high in lipid and ash compared to commercial canned salmon. There was no difference in the protein content between two kinds of canned fish. The contents of free amino acid and total amino acid of canned boiled rainbow trout were 330.9 mg/100 g and 18.2 g/100 g, respectively, and the major amino acids were glutamic acid (68.6 mg/100 g) and anserine (124.1 mg/100 g) in free amino acid and glutamic acid (18.0%), aspartic acid (8.6%), lysine (8.4%) and leucine (8.9%) in total amino acid. The mineral contents of canned boiled rainbow trout were 123.3 mg/100 g for potassium, 271.3 mg/100 g for calcium, 40.3 mg/100 g for magnesium, 2.4 mg/100 g for ferrous and 244.3 mg/100 g for phosphorus. The fatty acid composition of canned boiled rainbow trout was the highest (43.7%) in polyenoic acid, followed by monoenoic acid (28.8%) and saturated acid (27.5%) and their main fatty acids were 16:0 (18.4%), l8:1n-9 (20.6%), l8:2n-6 (17.3%) and 22:6n-3 (12.7%), respectively.

Effect of Dietary Supplementation of CLA-Containing Oil (CLAzen 80) on fatty Acid Composition of Egg Yolk in Laying Hens (산란계 사료내 CLA 함유 Oil (CLAzen 80) 첨가가 난황내 지방산 조성에 미치는 영향)

  • Hwangbo J.;Chang J. S.;Chung I. B.;Lee B. S.;Kim D. U.;Cho S. B.;Kim H. D.;Bae H. D.;Son J. H.;Hong U. C.;Choi N. J.
    • Korean Journal of Poultry Science
    • /
    • v.32 no.1
    • /
    • pp.35-41
    • /
    • 2005
  • The objectives of the present study were to investigate the effects of varying levels of dietary oil containing conjugated linoleic acid (CLA) on the egg production and fatty acid composition of egg yolk. Seventy-two 59-wk-old ISA Brown laying hens were randomly allotted to four dietary treatments, each consisting of three replicates with six birds per replicate. There were four treatments that consist of diets containing 0, 1, 2, or $3\%$ commercial CLA-containing oil. Egg production was not significantly different among the dietary treatments at 0, 2, 4, and 6 week. The proportion of saturated fatty acids such as C16:0 and C18:0 in egg yolk were increased, but that of monounsaturated fatty acid C18:1 was decreased by feeding CLA-containing oil supplementation. However, the proportion of polyunsaturated fatty acids such as C18:2 and C18:3 in egg yolk were not different among dietary treatments at 2 and 4 wk of the experiment. At 6 week, the proportion of C18:2 in egg yolk was decreased by feeding CLA-containing oil compared with the control. Polyunsaturated fatty acid:saturated fatty acid (P:S) ratio and n-6:n-3 polyunsaturated fatty acid ratio were similar across the treatments between 2 and 4 week. The P:S ratio was decreased by dietary CLA-containing oil supplementation at 6 week. The proportion of CLA in egg yolk was linearly increased with increasing levels of CLA-containing oil supplementation. In conclusion, dietary supplementation of CLA-containing oil to laying hens increased beneficially increased CLA content in their egg yolk.

Comparison between Propofol/Remifentanil and Ketamine/Remifentanil for TIVA in Beagle Dogs (비글견에서 Propofol/Remifentanil과 Ketamine/Remifentanil을 사용한 완전 정맥 내 마취법의 비교)

  • Choi, Woo-Shik;Jang, Hwan-Soo;Park, Jai-Soon;Yun, Sung-Ho;Kwon, Young-Sam;Jang, Kwang-Ho
    • Journal of Veterinary Clinics
    • /
    • v.28 no.5
    • /
    • pp.479-485
    • /
    • 2011
  • The cardiopulmonary responses during total intravenous anesthesia (TIVA) between remifentanil/propofol infusion and remifentanil/ketamine infusion in dogs were compared. Fourteen healthy adult beagle dogs were premedicated with acepromazine (0.1 mg/kg, SC) and medetomidine (20 ${\mu}g$/kg, IV), and anesthetized for 3 hr with remifentanil (0.5 ${\mu}g$/kg/min)/propofol (loading dose: 1 mg/kg, CRI: 0.3 mg/kg/min) CRI (group 'P') or remifentanil/ ketamine (loading dose : 5 mg/kg, CRI: 0.1 mg/kg/min) CRI (group 'K'), respectively. Hemodynamics, blood gas analysis and behavioral changes during recovery were measured. The level of anesthesia was determined by toe-web clamping test. The level of surgical anesthesia was maintained throughout the experiment in both groups. Systolic arterial pressure, mean arterial pressure, $PaO_2$ and $SpO_2$ in group 'K' were significantly higher than in group 'P', and were maintained near the normal ranges. In addition, $PaO_2$ in group 'K' was significantly lower than in group 'P'. However, diastolic arterial pressure, heart rate and respiratory rate were not significantly differed. Mean extubation time from the end of infusion was significantly reduced in group 'K', but mean sitting time was significantly reduced in group 'P'. Mean head-up time and mean walking time were not significantly differed. In group 'K', brief muscle rigidity, head waving and licking during recovery were observed. In conclusion, infusion rate of ketamine (0.1 mg/ kg/min) with remifentanil (0.5 ${\mu}g$/kg/min) is an appropriate for obtaining the surgical plane of anesthesia. These results showed that group 'K' had better cardiopulmonary function than group 'P'. That is, remifentanil/ketamine CRI is better TIVA protocol than remifentanil/propofol CRI for 3 hr surgery.

Improvement of an Simultaneous Determination for Clenbuterol and Ractopamine in Livestock Products using LC-MS/MS (LC-MS/MS를 이용한 축산물 중 clenbuterol과 ractopamine의 동시 분석법 개선)

  • Cho, Yoon-Jae;Chae, Young-Sik;Kim, Jae-Young;Kim, Hyung-Soo;Kang, Ilhyun;Do, Jung-Ah;Oh, Jae-Ho;Kwon, Kisung;Chang, Moon-Ik
    • Korean Journal of Food Science and Technology
    • /
    • v.45 no.1
    • /
    • pp.25-33
    • /
    • 2013
  • Clenbuterol and ractopamine, which are ${\beta}$-agonists, have been misused as a growth promoting agent in meat producing animals. Clenbuterol was banned for veterinary drug in Korea because of its problems regarding safety. Due to their adverse effects, such as cardiovascular and central nervous diseases on human health proper control and monitoring should be conducted. The existing analytical method of clenbuterol and ractopamine in the Food code was improved through our present study. The bovine muscle samples were subjected to enzymatic hydrolysis, extracted with ethyl acetate and defatted by hexane-methanol partitioning. A molecular imprinted polymer (MIP) solid phase extraction cartridge was used for clean-up and LC-MS/MS was operated in positive multiple reaction monitoring (MRM). Clenbuterol-$d_9$ and ractopamine-$d_3$ were used as an internal standard. The renewed method was validated according to the CODEX guideline. The limits of quantitation for clenbuterol and ractopamine were 0.2 and 0.5 ${\mu}g/kg$, respectively. The mean recoveries ranged in 104.2-113.5% for clenbuterol and in 107.6-118.1% for ractopamine. The improved method was able to save both time and expenses.

Geology of Athabasca Oil Sands in Canada (캐나다 아사바스카 오일샌드 지질특성)

  • Kwon, Yi-Kwon
    • The Korean Journal of Petroleum Geology
    • /
    • v.14 no.1
    • /
    • pp.1-11
    • /
    • 2008
  • As conventional oil and gas reservoirs become depleted, interests for oil sands has rapidly increased in the last decade. Oil sands are mixture of bitumen, water, and host sediments of sand and clay. Most oil sand is unconsolidated sand that is held together by bitumen. Bitumen has hydrocarbon in situ viscosity of >10,000 centipoises (cP) at reservoir condition and has API gravity between $8-14^{\circ}$. The largest oil sand deposits are in Alberta and Saskatchewan, Canada. The reverves are approximated at 1.7 trillion barrels of initial oil-in-place and 173 billion barrels of remaining established reserves. Alberta has a number of oil sands deposits which are grouped into three oil sand development areas - the Athabasca, Cold Lake, and Peace River, with the largest current bitumen production from Athabasca. Principal oil sands deposits consist of the McMurray Fm and Wabiskaw Mbr in Athabasca area, the Gething and Bluesky formations in Peace River area, and relatively thin multi-reservoir deposits of McMurray, Clearwater, and Grand Rapid formations in Cold Lake area. The reservoir sediments were deposited in the foreland basin (Western Canada Sedimentary Basin) formed by collision between the Pacific and North America plates and the subsequent thrusting movements in the Mesozoic. The deposits are underlain by basement rocks of Paleozoic carbonates with highly variable topography. The oil sands deposits were formed during the Early Cretaceous transgression which occurred along the Cretaceous Interior Seaway in North America. The oil-sands-hosting McMurray and Wabiskaw deposits in the Athabasca area consist of the lower fluvial and the upper estuarine-offshore sediments, reflecting the broad and overall transgression. The deposits are characterized by facies heterogeneity of channelized reservoir sands and non-reservoir muds. Main reservoir bodies of the McMurray Formation are fluvial and estuarine channel-point bar complexes which are interbedded with fine-grained deposits formed in floodplain, tidal flat, and estuarine bay. The Wabiskaw deposits (basal member of the Clearwater Formation) commonly comprise sheet-shaped offshore muds and sands, but occasionally show deep-incision into the McMurray deposits, forming channelized reservoir sand bodies of oil sands. In Canada, bitumen of oil sands deposits is produced by surface mining or in-situ thermal recovery processes. Bitumen sands recovered by surface mining are changed into synthetic crude oil through extraction and upgrading processes. On the other hand, bitumen produced by in-situ thermal recovery is transported to refinery only through bitumen blending process. The in-situ thermal recovery technology is represented by Steam-Assisted Gravity Drainage and Cyclic Steam Stimulation. These technologies are based on steam injection into bitumen sand reservoirs for increase in reservoir in-situ temperature and in bitumen mobility. In oil sands reservoirs, efficiency for steam propagation is controlled mainly by reservoir geology. Accordingly, understanding of geological factors and characteristics of oil sands reservoir deposits is prerequisite for well-designed development planning and effective bitumen production. As significant geological factors and characteristics in oil sands reservoir deposits, this study suggests (1) pay of bitumen sands and connectivity, (2) bitumen content and saturation, (3) geologic structure, (4) distribution of mud baffles and plugs, (5) thickness and lateral continuity of mud interbeds, (6) distribution of water-saturated sands, (7) distribution of gas-saturated sands, (8) direction of lateral accretion of point bar, (9) distribution of diagenetic layers and nodules, and (10) texture and fabric change within reservoir sand body.

  • PDF

The Geochemistry of Yuksipryeong Two-Mica Leucogranite, Yeongnam Massif, Korea (영남육괴내 육십령 복운모화강암에 대한 지화학적 연구)

  • Koh, Jeong-Seon;Yun, Sung-Hyo
    • The Journal of the Petrological Society of Korea
    • /
    • v.12 no.3
    • /
    • pp.119-134
    • /
    • 2003
  • Yuksipryeong two-mica granite presents strongly peraluminous characteristics in both mineralogy and geochemistry. It has high aluminum saturation index with 1.15∼l.20 and high corundum with 2.20∼2.98 wt% CIPW norm. As the color index is <16% and FeO$\^$T/+ MgO + TiO$_2$is average 1.9 wt%, it corresponds to leucogranite. Yuksipryeong two-mica leucogranite shows negative linear trend for TiO$_2$, Al$_2$O$_3$, FeO, Fe$_2$O$_3$, MgO, CaO, K$_2$O, P$_2$O$\_$5/, Rb, Ba, and Sr as SiO$_2$increases, and the positive relation of Zr and Th, which result from feldspar, biotite, apatite and zircon fractionation. Pegmatitic dike has higher SiO$_2$and P$_2$O$\_$5/, but lower another major elements. Yuksipryeong two-mica leucogranite has lower Rb, but higher Ba and Sr than Manaslu, Hercynian two-mica leucogranites, and S-type granites in Lachlan Fold Belt. Pegmatitic dike has higher Rb and Nb but lower Ba, Sr, Zr, Th, and Pb contents than Yuksipryeong two-mica leucogranite, resulting in removing or mobilizing for some trace elements from the granitic melt. Yuksipryeong two-mica leucogranite has total REEs with 95.7∼l23.3 ppm, and chondrite-normalized REE pattern is very steep ((La/Yb)$\_$N/ = 6.9∼24.8), light REEs (LREEs)-enriched End heavy REEs (HREEs)- depleted pattern with low to moderate Eu anomalies (Eu/Eu*= 0.7∼0.9). While pegmatitic dike has low total REEs with 7.0 ppm, and chondrite-normalized REE pattern is flat-pattern ((La/Yb)$\_$N/ = 2.1) with strong negative Eu anomalies (Eu/Eu*= 0.2). The melt compositions having formed two-mica leucogranites depend on not only the source rock but also the amounts of the residual remaining after melting of source rocks. The CaO/Na$_2$O and Rb/Sr-Rb/Ba ratios depend mainly on the composition of source rocks in the strongly peraluminous granite, that is, plagioclase/clay ratio of the source rocks. Yuksipryeong two-mica leucogranite has higher CaO/Na$_2$O and lower Rb/Sr-Rb/Ba ratios than Manaslu and Hercynian two-mica leucogranites (Millevaches and Gueret) derived from clay-rich, plagioclase-poor (polite), which suggest that the probable source rocks for Yuksipryeong two-mica leucogranite is clay-poor, plagioclase-rich quartzofeldspathic rocks. As the concentrations of Al$_2$O$_3$remain nearly constant but those of TiO$_2$increases as increasing temperature in the strong peraluminous melt, the Al$_2$O$_3$/TiO$_2$ratio may reflect relative temperature at which the melts have formed. Comparing the polite-derived Manaslu and Hercynian two- mica leucogranites, Manaslu two-mica leucogranite has higher Al$_2$O$_3$/TiO$_2$ratio than latter, and its melt have formed at relatively lower temperature ($\leq$ 875$^{\circ}C$) than Hercynian two-mica leucogranites. Likewise, comparing the quartzofeldspathic rock-derived granites, Yuksipryeong two-mica granite has higher Al$_2$O$_3$/TiO$_2$, ratio than S-type granites in Lachlan Fold Belt (>875$^{\circ}C$). The melt formed Yuksipryeong two-mica leucogranite are considered to have been formed at temperature at below the maximum 875$^{\circ}C$C$.

A Study on the 1889 'Nanjukseok' (Orchid, Bamboo and Rock) Paintings of Seo Byeong-o (석재 서병오(1862-1936)의 1889년작 난죽석도 연구)

  • Choi, Kyoung Hyun
    • Korean Journal of Heritage: History & Science
    • /
    • v.51 no.4
    • /
    • pp.4-23
    • /
    • 2018
  • Seo Byeong-o (徐丙五, 1862-1936) played a central role in the formation of the Daegu artistic community-which advocated artistic styles combining poetry, calligraphy and painting-during the Japanese colonial period, when the introduction of the Western concept of 'art' led to the adoption of Japanese and Western styles of painting in Korea. Seo first entered the world of calligraphy and painting after meeting Lee Ha-eung (李昰應, 1820-1898) in 1879, but his career as a scholar-artist only began in earnest after Korea was annexed by Japan in 1910. Seo's oeuvre can be broadly divided into three periods. In his initial period of learning, from 1879 to 1897, his artistic activity was largely confined to copying works from Chinese painting albums and painting works in the "Four Gentlemen" genre, influenced by the work of Lee Ha-eung, in his spare time. This may have been because Seo's principal aim at this time was to further his career as a government official. His subsequent period of development, which lasted from 1898 until 1920, saw him play a leading social role in such areas as the patriotic enlightenment movement until 1910, after which he reoriented his life to become a scholar-artist. During this period, Seo explored new styles based on the orchid paintings of Min Yeong-ik (閔泳翊, 1860-1914), whom he met during his second trip to Shanghai, and on the bamboo paintings of Chinese artist Pu Hua (蒲華, 1830-1911). At the same time, he painted in various genres including landscapes, flowers, and gimyeong jeolji (器皿折枝; still life with vessels and flowers). In his final mature period, from 1921 to 1936, Seo divided his time between Daegu and Seoul, becoming a highly active calligrapher and painter in Korea's modern art community. By this time his unique personal style, characterized by broad brush strokes and the use of abundant ink in orchid and bamboo paintings, was fully formed. Records on, and extant works from, Seo's early period are particularly rare, thus confining knowledge of his artistic activities and painting style largely to the realm of speculation. In this respect, eleven recently revealed nanjukseok (蘭竹石圖; orchid, bamboo and rock) paintings, produced by Seo in 1889, provide important clues about the origins and standards of his early-period painting style. This study uses a comparative analysis to confirm that Seo's orchid paintings show the influence of the early gunran (群蘭圖; orchid) and seongnan (石蘭圖; rock and orchid) paintings produced by Lee Ha-eung before his arrest by Qing troops in July 1882. Seo's bamboo paintings appear to show both that he adopted the style of Zheng Xie (鄭燮, 1693-1765) of the Yangzhou School (揚州畵派), a style widely known in Seoul from the late eighteenth century onward, and of Heo Ryeon (許鍊, 1809-1892), a student of Joseon artist Kim Jeong-hui (金正喜,1786-1856), and that he attempted to apply a modified version of Lee Ha-eung's seongnan painting technique. It was not possible to find other works by Seo evincing a direct relationship with the curious rocks depicted in his 1889 paintings, but I contend that they show the influence of both the late-nineteenth-century-Qing rock painter Zhou Tang (周棠, 1806-1876) and the curious rock paintings of the middle-class Joseon artist Jeong Hak-gyo (丁學敎, 1832-1914). In conclusion, this study asserts that, for his 1889 nanjukseok paintings, Seo Byeong-o adopted the styles of contemporary painters such as Heo Ryeon and Jeong Hak-gyo, whom he met during his early period at the Unhyeongung through his connection with its occupant, Lee Ha-eung, and those of artists such as Zheng Xie and Zhou Tang, whose works he was able to directly observe in Korea.

Comparison of Effects of Normothermic and Hypothermic Cardiopulmonary Bypass on Cerebral Metabolism During Cardiac Surgery (체외순환 시 뇌 대사에 대한 정상 체온 체외순환과 저 체온 체외순환의 임상적 영향에 관한 비교연구)

  • 조광현;박경택;김경현;최석철;최국렬;황윤호
    • Journal of Chest Surgery
    • /
    • v.35 no.6
    • /
    • pp.420-429
    • /
    • 2002
  • Moderate hypothermic cardiopulmonary bypass (CPB) has commonly been used in cardiac surgery. Several cardiac centers recently practice normothermic CPB in cardiac surgery, However, the clinical effect and safety of normothermic CPB on cerebral metabolism are not established and not fully understood. This study was prospectively designed to evaluate the clinical influence of normothermic CPB on brain metabolism and to compare it with that of moderate hypothermic CPB. Material and Method: Thirty-six adult patients scheduled for elective cardiac surgery were randomized to receive normothermic (nasopharyngeal temperature >34.5 $^{\circ}C$, n=18) or hypothermic (nasopharyngeal temperature 29~3$0^{\circ}C$, n=18) CPB with nonpulsatile pump. Middle cerebral artery blood flow velocity (VMCA), cerebral arteriovenous oxygen content difference (CAVO$_{2}$), cerebral oxygen extraction (COE), modified cerebral metabolic rate for oxygen (MCMRO$_{2}$), cerebral oxygen transport (TEO$_{2}$), cerebral venous desaturation (oxygen saturation in internal jugular bulb blood$\leq$50 %), and arterial and internal jugular bulb blood gas analysis were measured during six phases of the operation: Pre-CPB (control), CPB-10 min, Rewarm-1 (nasopharyngeal temperature 34 $^{\circ}C$ in the hypothermic group), Rewarm-2 (nasopharyngeal temperature 37 $^{\circ}C$ in the both groups), CPB-off and Post-CPB (skin closure after CPB-off). Postoperaitve neuropsychologic complications were observed in all patients. All variables were compared between the two groups. Result: VMCA at Rewarm-2 was higher in the hypothermic group (153.11$\pm$8.98%) than in the normothermic group (131.18$\pm$6.94%) (p<0.05). CAVO$_{2}$ (3.47$\pm$0.21 vs 4.28$\pm$0.29 mL/dL, p<0.05), COE (0.30$\pm$0.02 vs 0.39$\pm$0.02, p<0.05) and MCMRO$_{2}$ (4.71 $\pm$0.42 vs 5.36$\pm$0.45, p<0.05) at CPB-10 min were lower in the hypothermic group than in the normothermic group. The hypothermic group had higher TEO$_{2}$ than the normothermic group at CPB-10 (1,527.60$\pm$25.84 vs 1,368.74$\pm$20.03, p<0.05), Rewarm-2 (1,757.50$\pm$32.30 vs 1,478.60$\pm$27.41, p<0.05) and Post-CPB (1,734.37$\pm$41.45 vs 1,597.68$\pm$27.50, p<0.05). Internal jugular bulb oxygen tension (40.96$\pm$1.16 vs 34.79$\pm$2.18 mmHg, p<0.05), saturation (72.63$\pm$2.68 vs 64.76$\pm$2.49 %, p<0.05) and content (8.08$\pm$0.34 vs 6.78$\pm$0.43 mL/dL, p<0.05) at CPB-10 were higher in the hypothermic group than in the normothermic group. The hypothermic group had less incidence of postoperative neurologic complication (delirium) than the normothermic group (2 vs 4 patients, p<0.05). Lasting periods of postoperative delirium were shorter in the hypothermic group than in the normothermic group (60 vs 160 hrs, p<0.01). Conclusion: These results indicate that normothermic CPB should not be routinely applied in all cardiac surgery, especially advanced age or the clinical situations that require prolonged operative time. Moderate hypothermic CPB may have beneficial influences relatively on brain metabolism and postoperative neuropsychologic outcomes when compared with normothermic CPB.