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A Study of the Attitudes of Nursing Students toward Their Clinical Affiliation in a Mental Hospital (정신과간호 실습에 대한 간호 학생들의 태도 조사연구)

  • 김소야자
    • Journal of Korean Academy of Nursing
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    • v.3 no.3
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    • pp.15-26
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    • 1973
  • (Directed by Professor Hong, Shin Yong) Today, over seventy five Percent of the schools of nursing in Korea Provide a psychiatric experience in the basic curriculum. The psychiatric presents numerous major problems of adjustment to the student. The importance of positive attitudes toward the nursing care of psychiatric patients is recognized by the nursing profession. The purpose of this study was to determine the expressed attitudes of fifty-three nursing students toward their psychiatric affiliation. An attempt, also, was made to determine what implications these attitudes revealed relative to future program planning for students during the psychiatric nursing affiliation. A questionnaire, a Korean translation of the "psychiatric Nursing Attitude Questionnaire" by Milder Elizabeth Fletcher, was administered to fifty-three nursing students from three schools of nursing in Seoul, Who had completed a four-week psychiatric affiliation in a large mental hospital during Mar. 19, 1973 to May 19, 1973. The questionnaire of 100 statements was administered in the following way: (1) Part 1, Preconceptions. was. given in individual conferences with each subject, during the first few days of their affiliation, and again during the final week of the affiliation. The responses to Part Ⅰ were oral. (2) Part Ⅱ , Expectations, Part Ⅱ, Personal Relations, Part Ⅳ, Personal Feelings, and Part V , Attitudes and Activities of Patients were given to all of the subjects in a group meeting during the second week of the affiliation, and again. during the fourth week at the termination of the affiliation. Responses to Parts B, B, n, and f, wire written. Each of the 100 statements of the questionnaire was considered to be either Positive or Negative. A favorable response was assigned the Positive value of land an unfavorable response was assigned the Negative value of O. The coefficient of correlation was computed between the two sets of scores for the fifty-three nursing students., The mean score, the standard deviation, and the differences in the means on each of the five parts of the questionnaire were computed and the relationships calculated by a t-test. The results. of the study were as follows: 1. There was no significant correlation between the two sets of scores for the fifty-three nursing students during the four-week psychiatric affiliation. (r=573) 2. There was no significant difference in the mean scores between the first and final tests for any of the five parts of the questionnaire. 3. The Part.1, Preconceptions, data indicated nursing students enter the psychiatric affiliation with certain attitudes and preconceptions toward tile psychiatric affiliation which affect their psychiatric nursing experience, 4. The Part Ⅰ, Expectations, data indicated inappropriate expectations of students related to lack of experience, Lack of pre-psychiatric affiliation orientation, lack of social understanding, and feelings of insecurity. 5. The Part Ⅲ, Personal relations, data indicated some students have negative attitudes in personal relations with normal people in respect to psychological security and social responsibilities. 6. The Part Ⅳ, Personal feelings, data indicated nursing students have psychological insecurity & inappropriateness. 7. The Part Ⅴ, Attitudes and activities of patients, data indicated nursing students have negative attitudes of fear and frustration due to the psychotic behavior of certain patients in certain situations. 8. The data indicated preconceptions are predominate in unfavorable attitudes of students toward psychiatric nursing affiliation. Further researches indicated in the following areas: 1. Because of the limited number of students in this study, similar studies should be performed with larger groups for further validation of the results. 2. Because of the findings concerning the influence of the opinions of people in close contact with the students, similar studies of the attitudes of the staff in nursing schools, attitudes of graduate nurses and attitudes of the public should be done to determine weakness and strengths of present programs.

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Relationships between Community Unit and Environment Factor in Forest Vegetation of Mt. Dutasan, Pyeongchang-gun (평창 두타산 산림식생의 군집유형과 입지환경요인의 상관관계)

  • Lee, Jeong Eun;Shin, Jae Kwon;Kim, Dong Gap;Yun, Chung Weon
    • Journal of Korean Society of Forest Science
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    • v.106 no.3
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    • pp.275-287
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    • 2017
  • The purpose of this study was to analyze forest vegetation type classification and relationships between the type and environment factor in Mt. Dutasan. Data were collected by total of forty six plots using Z-M phytosociological method from June to October, 2016, and analyzed by vegetation classification, canopy layer structure and relationships between vegetation unit and environment factor using coincidence methods. As a result of vegetation type classification, Quercus mongolica community group was classified at a top level of vegetation hierarchy that was classified into Rhododendron schlippenbachii community and Betula costata community. R. schlippenbachii community was divided into Lychnis cognata group and R. schlippenbachii typical group. L. cognata group was subdivided into Veratrum oxysepalum subgroup and L. cognata typical subgroup. B. costata community was divided into Fraxinus mandshurica group and Betula schmidtii group. F. mandshurica group was subdivided into Weigela subsessilis subgroup and Cimicifuga heracleifolia subgroup. Therefore the forest vegetation was composed of six vegetation units with two kinds of bisected species groups and fourteen species groups. As the result of an analysis of canopy layer structure, there were two kinds of structures with monotonous structures V. oxysepalum subgroup (vegetation units 1), L. cognata typical subgroup (vegetation units 2), W. subsessilis subgroup (vegetation units 4) and complicated structures R. schlippenbachii typical group (vegetation units 3), C. heracleifolia subgroup (vegetation units 5), Betula schmidtii group (vegetation units 6). The vertical layer structure of vegetation unit 5 was the most developed and vegetation unit 6 had the lowest coverage of herb layer. According to the correlation between vegetation unit and environmental factor, R. schlippenbachii community (vegetation units 1~3) and B. costata community (vegetation units 4~6) were classified based on 1,100 m of altitude, middle slope, twenty of slope degree, twenty percents of bare rock and thirty centimeters of DBH in tree layer. R. schlippenbachii community (vegetation units 1~3) showed positive correlation with altitude, topography and B. costata community (vegetation units 4~6) showed negative correlation tendency with them.

Total Arterial 011-Pump Coronary Revascularization with Multiple Y Arterial Composite Grafts (다중 복합 Y 동맥 이식편(Multiple Y Composite Craft)을 이용한 완저너 동맥 무인공 심폐바이패스 관상동맥우회술)

  • Kim Do-kyun;Lee Kyo Jgon;Joo Hyun Chul;Li Gyjong;Ahn Jiyoung;shim Yungee;Yoo Kyung Jong
    • Journal of Chest Surgery
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    • v.38 no.8 s.253
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    • pp.551-556
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    • 2005
  • Background: Complete arterial off-pump coronary artery bypass grafting (OPCAB) by sequential anastomoses with one or two arterial grafts provides favorable outcomes. However, problems of insufficient graft length, hypopefusion, kinking of graft, and unfavorable course of graft may be encountered. To solve these problems, we have used different technique with multiple arterial Y composite graft to allow end-to-side rather than sequential anastomoses and evaluated the results of this method. Material and Method: Between February 2003 and October 2004, If patients underwent total arterial OPCAB using multiple arterial V composite grafts with left internal mammary artery (LIMA), radial artery (RA), and right internal mammary artery (RIMA). We divided RA into multiple segments by number of distal target site after measuring of individual proper length and constructed arterial composite graft. One of segments was sutured end-to-side to LIMA and other segment was sutured end-to-side to the previously constructed radial graft. Postoperative graft patency was evaluated in 6f patients by multi-slice computed tomegraphy. Result: An average of $2.5\pm0.6$ arteries and $3.7pm0.7$ distal anastomoses per patient were done. There was no perioperative myocardial infarction, clinical hypoperfusion syndromes, and operative mortality. Postoperative mean CK-MB level was $17.4pm29.7\;IU/L.$Overall graft patency was $99.1\%\;(214/216)(LIMA:\;100\%,\;RA:\;98.4\%,\;RIMA:\;100\%).$ Conclusion: This technique allows total arterial OPCAB without technical problems and provides excellent early clinical results and graft patency. We believe that this technique is more convenient in the obtuse marginal area compared to sequential technique, and helpful in patients who require complex arterial grafting.

Spatial and Temporal Variations of Environmental Factors and Phytoplankton Community in Lake Yongdam, Korea (용담호에서 환경요인과 식물플랑크톤의 시공간적 변동)

  • Kwon, Sang-Yong;Kim, Young-Geel;Yih, Won-Ho;Lim, Byung-Jin;Kim, Bom-Chul;Heo, Woo-Myung
    • Korean Journal of Ecology and Environment
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    • v.39 no.3 s.117
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    • pp.366-377
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    • 2006
  • Environmental gradients and phytoplankton community were studied on a monthly basis, at 3 stations of Lake Yongdam, from April 2002 March 2004. During July to August, thermocline formed at the depth of about 10 m, but it was lowerd depth, in between 25${\sim}$30 m in October. Monthly variations of the epilimnetic (0${\sim}$5 m) TP concentrations at station 1, 2 and 3 were in the range of $5.1{\sim}36.1\;mg\;P\;{\cdot}\;m^{-3}$, $6.1{\sim}77.7\;mg\;P\;{\cdot}\;m^{-3}$ and $6.7{\sim}47.7\;mg\;P\;{\cdot}\;m^{-3}$ respectively; with higher concentrations at the upstream areas showing. Monthly average of the epilimnetic (0${\sim}$5 m) TN concentration at Station 1 was in the range of $0.88{\sim}1.73\;mg\;N\;{\cdot}\;L^{-1}$, and Station 3 was in the range of $0.94{\sim}2.77\;mg\;N\;{\cdot}\;L^{-1}$, which is higher if compared with the values of station 1. Transparency wa:s in the range of 0.8${\sim}$6.7 m, with lower values at upstream areas and higher at the downstream area. As for phytoplankton, during the winter season, diatoms had high appearance rate; during the spring season, Cyclotella comta, Aulacoseira ambigua f. spiralis, A. granulata and similar diatoms, during spring and summer Ankistrodesmus spiralis, Chodatella subsala, Crucigenia irregularis, Coelastrum cambricum, Scenedesmus ecornis v. ecornis.

A Development and Application of the Landscape Evaluation Model Based on the Biotope Classification (비오톱 유형분류를 기반으로 한 경관평가 모형개발 및 적용)

  • Park, Cheon-Jin;Ra, Jung-Hwa;Cho, Hyun-Ju;Kim, Jin-Hyo;Kwon, Oh-Sung
    • Journal of the Korean Institute of Landscape Architecture
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    • v.40 no.4
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    • pp.114-126
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    • 2012
  • The purpose of this study is to find ways of the view evaluation of biotope classification before development by selecting an area, which is as large as about $10.0km^2$ around Non Gong Up, Auk Po Myun, Dalsung Gun, Daugu where the large project has been planned, as a subject of this study. The results of this study are as follows. Because of the classification of biotope, there are 23 kinds of types that are subdivided into 140 types. Three surveys for selecting the assessment indicators were performed. The first survey analyzed the importance of 22 selected assessment indicators based on the evaluation of an existing literature review and on the spot research. The second survey performed factor analysis and reclassified the value indicators. The third survey computed additive values of the selected assessment indicators. It used a method of standardizing the average importance of indicators by making their sum equal by 10. Theses additive values were then multiplied by each grade of indicators in order to make a final evaluation. The number of assessment indicators finally selected through the survey of asking specialist is vitality elements, visual obstructs elements etc 19. According to the result of evaluation of 1st, 1 grade spaces which especially valuable is analyzed that 7 spaces, 2 grade spaces for 4, 3 grade spaces for 5, 4 grade space for 2, 5 grade space for 5. Because of the evaluation of 2st, 1 grade spaces which especially valuable(1a, 1b) is analyzed that 15 spaces, 2 grade spaces which valuable is analyzed that 28 space. As the evaluation of site suitability model of this study couldn't have high applicability to other similar area because of having only one site as a subject, it is needed to do synthesize and standardization of various examples to have higher objectivity later.

Standardization and Reliability and Validity of the Korean Edition of Profile of Mood States(K-POMS) (한국판 기분상태척도(K-POMS)의 표준화와 신뢰도와 타당도 평가)

  • Kim, Eui-Joong;Lee, Sang-Ick;Jeong, Do-Un;Shin, Min-Sup;Yoon, In-Young
    • Sleep Medicine and Psychophysiology
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    • v.10 no.1
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    • pp.39-51
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    • 2003
  • Objectives: The Profile of Mood States (POMS) has been used broadly and frequently in various medical studies with various subjects. For the development and application of the Korean edition of POMS, called K-POMS, we translated POMS into Korean and then evaluated the reliability and validity of K-POMS. Methods: The subjects were 161 male students with a mean age of 18.1 years (15-30) and 244 female students with a mean age of 16.6 years (14-23). They were requested to perform K-POMS and SCL-90-R (Korean version) at the same time. Means, reliability coefficients, and test-retest correlations of K-POMS were calculated. Content validities, correlations with SCL-90-R, and discrimination validities in comparison with 76 depressive patients were obtained, and factor analyses were carried out. Results: Mean scores of Total Mood Disturbance (TMD) and some subscales (T, F, C, V factor) showed a significant difference between male and female students. The internal consistency coefficient ($\alpha$) of the total 65 items was 0.93, and ranged from 0.67 to 0.90 for subscales. Test-retest correlations of 43 subjects ranged from 0.27 to 0.63. Seven psychiatrists rated the properness of the content of each item as more than moderate degree (mean scale points=2.66, in the range of 0 to 4). Every subscale of KPOMS exhibited significant correlation with the matching subscale of SCL-90-R. Mean scores of K-POMS of the total 405 subjects were significantly different from those of the 76 depressive subjects after age correction. Six factors were extracted, accounting for 51.2% of total variance. Factor 6 consisted of 6 items which came from various subscales of POMS and represented "uncertainty and helplessness," which may be somewhat different to depression or sadness proper. Conclusion: The validity and reliability of K-POMS could be confirmed. The significant difference in K-POMS scores between depressive subjects and normal subjects suggests that K-POMS can be used clinically for the evaluation and screening of depression. The main structure of K-POMS is very similar to that of POMS, except the Confusion-Bewilderment factor which shows weak factor consistency in K-POMS. This may reflect some emotional characteristic of Koreans such as an undifferentiated aspect of cognitive efficiency. The sixth factor newly extracted from K-POMS also may be indicative of an unique emotional aspect of young Koreans.

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A study on the smile of Korean Youth compared with twenty years ago (20년전과 비교한 한국청년의 미소 변화에 관한 연구)

  • Beom, Seung-Gyun;Jung, Ji-Hye;Kim, Tae-Young;Lee, Kyung-Eun;Dong, Jin-Keun
    • The Journal of Korean Academy of Prosthodontics
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    • v.50 no.3
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    • pp.162-168
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    • 2012
  • Purpose: Teeth are generally exposed when people smiling. Moreover, the exposed teeth and soft tissue when smiling becomes an important guideline for esthetically prosthetic restoration. This research is to compare and find out differences of Korean young men's smile living in presence and twenty years ago. Materials and methods: Subjects, 100 young men (50 male and 50 female), were required about several aspects; normally developed physical condition, no psychological or genetic disorders, a fine face with no loss of teeth, no experience in orthodontic or prosthetic treatment, relatively normal occlusion, aged between 20-29. The photos of the subject at rest position and front face when fully smiled were taken three times. 100 photos (50 male and 50 female) were chosen at random from the 240 university students' smile photos taken by Yoon and his colleagues in 1991. By Hulsey's method of measuring smile, several factors; the change of upper lip curvature, the change of the relation between the upper lip and teeth, parallelism between Mx. incisor and lower lip, contact relation between Mx. incisor and lower lip and teeth displayed in a smile, were measured and analyzed. Meanwhile, ten dentists assessed aesthetic evaluation about men and women's smile for twice and recorded and compared smile score. The -test (P<.05) was used to compare the measured value. The difference of smile score was analyzed by t-test (P<.05). Results: The smile score calculated in 2011 (60.22) was higher than that of 1991 (52.80). Among five measurement categories, the noticeable difference was distinguished from two factors; the change of upper lip curvature and contact relation between Mx. incisor and lower lip. Conclusion: The Korean young men's smile has been considerably improved for twenty years. And it is found that the change of upper lip curvature plays an important role, that is, the smile formed with an ascended labial commissure has been increased significantly.

LCD 연구 개발 동향

  • 이종천
    • The Magazine of the IEIE
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    • v.29 no.6
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    • pp.76-80
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    • 2002
  • 'Liquid Crystal의 상전이(相轉移)와 광학적 이방성(異方性)이 1888년과 1889년 F. Reinitzer와 O. Lehmann에 의해 Monatsch Chem.과 Z.Physikal.Chem.에 각각 보고된 후 부터 제2차 세계대전이 끝난 뒤인 1950년대 까지는 Liquid Crystal을 단지실험실에서의 기초학문 차원의 연구 대상으로만 다루어 왔다. 1963년 Williams가 Liquid Crystal Device로는 최초로 특허 출원을 하였으며, 1968년 RCA사의 Heilmeier등은 Nematic 액정(液晶)에 저주파(低周波) 전압(電壓)을 인가하면 투명한 액정이 혼탁(混濁)상태로 변화하는 '동적산란(動的散亂)'(Dynamic Scattering) 현상을 이용하여 최초의 DSM(Dynamic Scattering Mode) LCD(Liquid Crystal Display)를 발명하였다. 비록 150V 이상의 높은 구동전압과 과소비전력의 특성 때문에 실용화에는 실패하였지만 Guest-Host효과와 Memory효과 등을 발견하였다. 1970년대에 이르러 실온에서 안정되게 사용 가능한 액정물질들이 합성되고(H. Kelker에 의해 MBBA, G. Gray에 의한 Cyano-Biphenyl 액정의 합성), CMOS 트랜지스터의 발명, 투명도전막(ITO), 수은전지등의 주변기술들의 발전으로 인하여 LCD의 상품화가 본격적으로 이루어지게 되었다. 1971년에는 M. Shadt, W. Helfrich, J.L. Fergason등이 TN(Twisted Nematic) LCD를 발명하여 전자 계산기와 손목시계에 응용되었고, 1970년대 말에는 Sharp에서 Dot Matrix형의 휴대형 컴퓨터를 발매하였다. 이러한 단순 구동형의 TN LCD는 그래픽 정보를 표시하는 데에는 품질의 한계가 있어 1979년 영국의 Le Comber에 의해 a-Si TFT(amorphous Silicon Thin Film Transistor) LCD의 연구가 시작되었고, 1983년 T.J. Scheffer, J. Nehring, G. Waters에 의해 STN(Super Twisted Nematic) LCD가 창안되었고, 1980년 N. Clark, S. Lagerwall 및 1983년 K.Yossino에 의해 Ferroelectric LCD가 등장하여 LCD의 정보 표시량 증대에 크게 기여하였다. Color화의 진전은 1972년 A.G. Ficher의 셀 외부에 RGB(Red, Green, Blue) filter를 부착하는 방안과, 1981년 T. Uchida 등에 의한 셀 내부에 RGB filter를 부착하는 방법에 의해 상품화가 되었다. 1985년에는 J.L. Fergason에 의해 Polymer Dispersed LCD가 발명되었고, 1980년대 중반에 이르러 동화상(動畵像) 표시가 가능한 a-Si TFT LCD의 시제품(試製品) 개발이 이루어지고 1990년부터는 본격적인 양산 시대에 접어들게 되었다. 1990년대 초에는 STN LCD의 Color화 및 대형화(大型化) 고(高)품위화에 힘입어 Note-Book PC에 LCD가 본격적으로 적용이 되었고, 1990년대 후반에는TFT LCD의 표시품질 대비 가격경쟁력 확보로 인하여 Note-Book PC 시장을 독점하기에 이르렀다. 이후로는 TFT LCD의 대형화가 중요한 쟁점으로 부각되고 있고, 1995년 삼성전자는 당시 세계최대 크기의 22' TFT LCD를 개발하였다. 또한 LCD의 고정세(高情細)화를 위해 Poly Si TFT LCD의 개발이 이루어졌고, 디지타이져 일체형 LCD의 상품화가 그 응용의 폭을 넓혔으며, LCD의 대형화를 위해 1994년 Canon에 의해 14.8', 21' 등의 FLCD가 개발되었다. 대형화 방안으로 Tiled LCD 기술이 개발되고 있으며, 1995년에 Sharp에 의해 21' 두장의 Panel을 이어 붙인 28' TFT LCD가 전시되었고 1996년에는 21' 4장의 Panel을 이어 붙인 40'급 까지의 개발이 시도 되었으며 현재는 LCD의 특성향상과 생산설비의 성능개선과 안정적인 공정관리기술을 바탕으로 삼성전자에서 단패널 40' TFT LCD가 최근에 개발되었다. Projection용 디스플레이로는 Poly-Si TFT LCD를 이용하여 $25'{\sim}100'$사이의 배면투사형과 전면투사형 까지 개발되어 대형 TV시장을 주도하고 있다. 21세기 디지털방송 시대를 맞아 플라즈마디스플레이패널(PDP) TV, 액정표시장치 (LCD)TV, 강유전성액정(FLCD) TV 등 2005년에 약 1500만대 규모의 거대 시장을 형성할 것으로 예상되는 이른바 '벽걸이TV'로 불리는 차세대 초박형 TV 시장을 선점하기 위하여 세계 가전업계들이 양산에 총력을 기울이고 있다. 벽걸이TV 시장이 본격적으로 형성되더라도 PDP TV와 LCD TV가 직접적으로 시장에서 경쟁을 벌이는 일은 별로 없을 것으로 보인다. 향후 디지털TV 시장이 본격적으로 열리면 40인치 이하의 중대형 시장은 LCD TV가 주도하고 40인치 이상 대화면 시장은 PDP TV가 주도할 것으로 보는 시각이 지배적이기 때문이다. 그러나 이러한 직시형 중대형(重大型)디스플레이는 그 가격이 너무 높아서 현재의 브라운관 TV를 대체(代替)하기에는 시일이 많이 소요될 것으로 추정되고 있다. 그 대안(代案)으로는 비교적 저가격(低價格)이면서도 고품질의 디지털 화상구현이 가능한 고해상도 프로젝션 TV가 유력시되고 있다. 이러한 고해상도 프로젝션 TV용으로 DMD(Digital Micro-mirror Display), Poly-Si TFT LCD와 LCOS(Liquid Crystals on Silicon) 등의 상품화가 진행되고 있다. 인터넷과 정보통신 기술의 발달로 휴대형 디스플레이의 시장이 예상 외로 급성장하고 있으며, 요구되는 디스플레이의 품질도 단순한 문자표시에서 그치지 않고 고해상도의 그래픽 동화상 표시와 칼라 표시 및 3차원 화상표시까지 점차로 그 영역이 넓어지고 있다. <표 1>에서 보여주는 바와 같이 LCD의 시장규모는 적용분야 별로 지속적인 성장이 예상되며, 새로운 응용분야의 시장도 성장성을 어느 정도 예측할 수 있다. 따라서 LCD기술의 연구개발 방향은 크게 두가지로 분류할 수 있으며 첫째로는, 현재 양산되고 있는 LCD 상품의 경쟁력강화를 위하여 원가(原價) 절감(節減)과 표시품질을 향상시키는 것이며 둘째로는, 새로운 타입의 LCD를 개발하여 기존 상품을 대체하거나 새로운 시장을 창출하는 분야로 나눌 수 있다. 이와 같은 관점에서 현재 진행되고 있는 LCD기술개발은 다음과 같이 분류할 수 있다. 1) 원가 절감 2) 특성 향상 3) New Type LCD 개발.

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Pressure Drop Predictions Using Multiple Regression Model in Pulse Jet Type Bag Filter Without Venturi (다중회귀모형을 이용한 벤츄리가 없는 충격기류식 여과집진장치 압력손실 예측)

  • Suh, Jeong-Min;Park, Jeong-Ho;Cho, Jae-Hwan;Jin, Kyung-Ho;Jung, Moon-Sub;Yi, Pyong-In;Hong, Sung-Chul;Sivakumar, S.;Choi, Kum-Chan
    • Journal of Environmental Science International
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    • v.23 no.12
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    • pp.2045-2056
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    • 2014
  • In this study, pressure drop was measured in the pulse jet bag filter without venturi on which 16 numbers of filter bags (Ø$140{\times}850{\ell}$) are installed according to operation condition(filtration velocity, inlet dust concentration, pulse pressure, and pulse interval) using coke dust from steel mill. The obtained 180 pressure drop test data were used to predict pressure drop with multiple regression model so that pressure drop data can be used for effective operation condition and as basic data for economical design. The prediction results showed that when filtration velocity was increased by 1%, pressure drop was increased by 2.2% which indicated that filtration velocity among operation condition was attributed on the pressure drop the most. Pressure was dropped by 1.53% when pulse pressure was increased by 1% which also confirmed that pulse pressure was the major factor affecting on the pressure drop next to filtration velocity. Meanwhile, pressure drops were found increased by 0.3% and 0.37%, respectively when inlet dust concentration and pulse interval were increased by 1% implying that the effects of inlet dust concentration and pulse interval were less as compared with those changes of filtration velocity and pulse pressure. Therefore, the larger effect on the pressure drop the pulse jet bag filter was found in the order of filtration velocity($V_f$), pulse pressure($P_p$), inlet dust concentration($C_i$), pulse interval($P_i$). Also, the prediction result of filtration velocity, inlet dust concentration, pulse pressure, and pulse interval which showed the largest effect on the pressure drop indicated that stable operation can be executed with filtration velocity less than 1.5 m/min and inlet dust concentration less than $4g/m^3$. However, it was regarded that pulse pressure and pulse interval need to be adjusted when inlet dust concentration is higher than $4g/m^3$. When filtration velocity and pulse pressure were examined, operation was possible regardless of changes in pulse pressure if filtration velocity was at 1.5 m/min. If filtration velocity was increased to 2 m/min. operation would be possible only when pulse pressure was set at higher than $5.8kgf/cm^2$. Also, the prediction result of pressure drop with filtration velocity and pulse interval showed that operation with pulse interval less than 50 sec. should be carried out under filtration velocity at 1.5 m/min. While, pulse interval should be set at lower than 11 sec. if filtration velocity was set at 2 m/min. Under the conditions of filtration velocity lower than 1 m/min and high pulse pressure higher than $7kgf/cm^2$, though pressure drop would be less, in this case, economic feasibility would be low due to increased in installation and operation cost since scale of dust collection equipment becomes larger and life of filtration bag becomes shortened due to high pulse pressure.

Effects of Momordica charantia Saponins on In vitro Ruminal Fermentation and Microbial Population

  • Kang, Jinhe;Zeng, Bo;Tang, Shaoxun;Wang, Min;Han, Xuefeng;Zhou, Chuanshe;Yan, Qiongxian;He, Zhixiong;Liu, Jinfu;Tan, Zhiliang
    • Asian-Australasian Journal of Animal Sciences
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    • v.29 no.4
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    • pp.500-508
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    • 2016
  • This study was conducted to investigate the effects of Momordica charantia saponin (MCS) on ruminal fermentation of maize stover and abundance of selected microbial populations in vitro. Five levels of MCS supplements (0, 0.01, 0.06, 0.30, 0.60 mg/mL) were tested. The pH, $NH_3-N$, and volatile fatty acid were measured at 6, 24, 48 h of in vitro mixed incubation fluids, whilst the selected microbial populations were determined at 6 and 24 h. The high dose of MCS increased the initial fractional rate of degradation at t-value = 0 ($FRD_0$) and the fractional rate of gas production (k), but decreased the theoretical maximum of gas production ($V_F$) and the half-life ($t_{0.5}$) compared with the control. The $NH_3-N$ concentration reached the lowest concentration with 0.01 mg MCS/mL at 6 h. The MSC inclusion increased (p<0.001) the molar proportion of butyrate, isovalerate at 24 h and 48 h, and the molar proportion of acetate at 24 h, but then decreased (p<0.05) them at 48 h. The molar proportion of valerate was increased (p<0.05) at 24 h. The acetate to propionate ratio (A/P; linear, p<0.01) was increased at 24 h, but reached the least value at the level of 0.30 mg/mL MCS. The MCS inclusion decreased (p<0.05) the molar proportion of propionate at 24 h and then increased it at 48 h. The concentration of total volatile fatty acid was decreased (p<0.001) at 24 h, but reached the greatest concentration at the level of 0.01 mg/mL and the least concentration at the level of 0.60 mg/mL. The relative abundance of Ruminococcus albus was increased at 6 h and 24 h, and the relative abundance of Fibrobacter succinogenes was the lowest (p<0.05) at 0.60 mg/mL at 6 h and 24 h. The relative abundance of Butyrivibrio fibrisolvens and fungus reached the greatest value (p<0.05) at low doses of MCS inclusion and the least value (p<0.05) at 0.60 mg/mL at 24 h. The present results demonstrates that a high level of MCS quickly inhibits in vitro fermentation of maize stover, while MCS at low doses has the ability to modulate the ruminal fermentation pattern by regulating the number of functional rumen microbes including cellulolytic bacteria and fungi populations, and may have potential as a feed additive applied in the diets of ruminants.