• 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.

• Progress in Medical Physics
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• v.16 no.4
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• pp.166-175
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• 2005

The purpose of this study is to develop the optimization method for adjusting the film isocenter shift and to suggest the quantitative acceptable criteria for film dosimetry after optimization In the dynamic conformal arc radiation therapy (DCAR). The DCAR planning was peformed In 7 patients with brain metastasis. Both absolute dosimetry with ion chamber and relative film dosimetry were peformed throughout the DCAR using BrainLab's micro-multileaf collimator. An optimization method for obtaining the global minimum was used to adjust for the error in the film isocenter shift, which is the largest pan of systemic errors. The mean of point dose difference between measured value using ion chamber and calculated value acquired from planning system was $0.51{\pm}0.43\%$ and maximum was $1.14\%$ with absolute dosimetry These results were within the AAPM criteria of below $5\%$. The translation values of film isocenter shift with optimization were within ${\pm}$1 mm in all patients. The mean of average dose difference before and after optimization was $1.70{\pm}0.35\%$ and $1.34{\pm}0.20\%$, respectively, and the mean ratios over $5\%$ dose difference was $4.54{\pm}3.94\%$ and $0.11{\pm}0.12\%$, respectively. After optimization, the dose differences decreased dramatically and a ratio over $5\%$ dose difference and average dose difference was less than $2\%$. This optimization method is effective in adjusting the error of the film isocenter shift, which Is the largest part of systemic errors, and the results of this research suggested the quantitative acceptable criteria could be accurate and useful in clinical application of dosimetric verification using film dosimetry as follows; film isocenter shift with optimization should be within ${\pm}$1 mm, and a ratio over $5\%$ dose difference and average dose difference were less than $2\%$.

• Journal of Korean Medical classics
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• v.4
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• pp.101-126
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• 1990

At early Cheong (淸) dynasty, in medical aspect by dependent on practical studying attitude that must found a theory only by an evidence, there had been a tendancy that hoped direct research of sages' mind-eye by escaping the theory of individual classes since Geum-Won (金-元) dynasty. Yoo Chang (喩昌), born in Man-Ryeok (萬曆) 12th year of Myung (明) dynasty (A.D.1583) and dead in Gang-Hee (康熙) 3rd year of Cheong (淸) dynasty (A.D.1664). The results were as follows after studying his practical idea of medicine. 1. Yoo Chang, by recognizing the ${\ll}$Sang-Han-Ro${\gg}$ has lost its true meaning after commented by Wang Hee (王熙), Lim Eog (林億), Seong Moo-I (成無巳), etc. according to Bang Yoo-Jip's (方有執) Chak-Gan-Jung-Jeong (錯簡重訂) theory, he diversified the protocal of ${\ll}$Sang-Han-Ro${\gg}$ 397 method and arranged under Six Meridian part. (六經) 2. The theory of Sam-Gang-Jeong-Rip (三綱鼎立) can be summerized Gye-Ji (桂枝) syndrome which is the case of Wind (風) has injured Wi (衛) stage, Ma-hwang (麻黃) syndrome which is the case of Cold (寒) has injured Yeong (榮) stage, Dae-Cheong-Ryong (大靑龍) syndrome which is the case both of Wind-Cold (風寒) has injured Yeong-Wi (榮衛) stage, and there has been Sam-Gang-Jeong-Rip theory by anterior medical practitioners already but the person who formally used its Sam-Gang-Jeong-Rip term is Yoo Chang. 3. Yoo Chang seized the On Byeng (溫病) by dividing three category and in Byon-Jeung-Si-Chi (辨證施治) he influenced to many aspect of establishment of later Byon-Jeung system On-Byong (溫病의 辨證體系) pertaining to Triple-Warmer by O-Dang (吳瑭) introducing Triple-Wanner Theory. (三焦理論) 4. At Chu-Jo-Ron (秋燥論) of ${\ll}$EUi-Moon-Beop-Ryo${\gg}$, while ${\ll}$Nae-Gyeong${\gg}$ describing if humidity injury Lung, then occur a disorder in it, Yoo Chang recognized that of au tuam when dryness injure Lung there occure a disorder is it so he insisted that at this case, must use Cheong-Joe-Goo-Pye method (淸操救肺法) withherbs, pertaing to Gam-Yoo-Ja-Yoon(甘柔滋潤性) property and he invented Cheong-Joe-Goo-Pye-Tang. (淸操救肺湯) 5. Yoo Chang', so called, Dae-Gi (大氣) indicates Yang-Gi (陽氣) of chest, he insisted that man's creation and every physiological activity depends on maintainence of Dae-Gi, and it integrate Yeong-Gi (榮氣), Wea-Gi (衛氣), Jong-Gi (宗氣), Jang-Boo-Ji-Gi (臟腑之氣), Gyeong-Rak-Ji-Gi. (經絡之氣) 6. Yoo Chang's expression about partical function and character of stomach, not only bolster its theory of historical physician's expression, that is stomach is. foundatness of postnatal period, but also it has corresponding aspect with modern medicine and clinic. 7. Yoo Chang emphasized "if one cure a disease, be must understood the character of disease first and use drugs later" (先議病 後用藥) phrase about of drug usage, and his theory of Geup-Rew-Man-Joo method (急流挽舟) and three therapy of Simple Ascite (單腹腸) are all unique opinion based upon this phrase mentioned above. 8. Yoo Chang's practical idea of medicine greatly influenced to Jang Ro (張璐), Hwang Won-A (黃元御), Oh Eui-Rak (吳儀洛), Joo Yang-Joon (周揚俊), etc. and theory of Sam-Gang-Jeng-Rip (三綱鼎立), Triple Warmer Theory of On Byong (溫疫의 三焦論治), Chu-Jo-Ron (秋燥論), Dae-Gi-Ron (大氣論) etc. became important object to student of Sang-Han (傷寒) and On-Byeng. (溫病) 9. Yoo Chang's Writings has more practical meaning than other physician's, especially, later the idea of Sang-Han (傷寒) and On-Byong (溫病) greatly contributed to development of Sang-Han theory and formation of On-Byong theory.

• Progress in Medical Physics
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• v.22 no.1
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• pp.52-58
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• 2011

Our goal is to assess the suitability of a glass dosimeter on detection of high-energy electron beams for clinical use, especially for radiation therapy. We examined the dosimetric characteristics of glass dosimeters including dose linearity, reproducibility, angular dependence, dose rate dependence, and energy dependence of 5 different electron energy qualities. The GD was irradiated with high-energy electron beams from the medical linear accelerator andgamma rays from a cobalt-60 teletherapy unit. All irradiations were performed in a water phantom. The result of the dose linearity for high-energy electron beams showed well fitted regression line with the coefficient of determination; $R^2$ of 0.999 between 6 and 20 MeV. The reproducibility of GDs exposed to the nominal electron energies 6, 9, 12, 16, and 20 MeV was ${\pm}1.2%$. In terms of the angular dependence to electron beams,GD response differences to the electron beam were within 1.5% for angles ranging from $0^{\circ}$ to $90^{\circ}$ and GD's maximum response differencewas 14% lower at 180o. In the dose rate dependence, measured dose values were normalized to the value obtained from 500 MU/min. The uncertainties of dose rate were measured within ${\pm}1.5%$ except for the value from 100 MU/min. In the evaluation of the energy dependence of the GD at nominal electron energies between 6 and 20 MeV, we obtained lower responses between 1.1% and 4.5% based on cobalt-60 beam. Our results show that GDs have a considerable potentiality for measuring doses delivered by high-energy electron beams.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.31 no.2
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• pp.20-30
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• 2013

'Paulownia tree', one of a tree species which has been with human civilization, has been widely used as a garden plant. The purpose of this study is to investigate concrete species of 'paulownia tree,' which had been planted in Korean traditional garden, the position of plantation, and consider its usefulness therefrom. The results of the study can be summarized as follows. 1. As the result of considering old literatures as encyclopedia, agricultural book (農書), gardening book, etc., there's a difference in the description of 'paulownia tree' depending on the complier, as well, the classification of concrete species is quite ambiguous. Therefore, it judged a limit which is planted based on point of the compass is not apply to species of tress of paulownia tree. Merely, the point of suitability and evasion(宜忌) related to the plantation of 'paulownia tree' could be identified in "Jeungbosanrimgyeongje(增補山林經濟) and "Imwongyeongjeji(林園經濟志)", not "Sanrimgyeongje (山林經濟)". 2. It could be confirmed again through poetry and prose which describe old garden that the words such as 'O(梧)', 'Dong(桐)', 'Odong(梧桐)', etc. were used without significant division. However, it is supposed that the species 'Odong' which was actually adopted at the garden might be Catalpa as well including Korean Paulownia and Chinese parasol tree. 3. It is considered that the reference point of suitability and evasion(宜忌) regarding 'paulownia tree' plantation was not generally applied. That is, species of paulownia tree was not divided for planting according to direction, as well, they seemed to willingly plant paulownia trees nearby the house as well, e.g. front yard or nearby yard, etc. 4. The usefulness of paulownia tree as a garden plant of an old garden played a role of 'the messenger of fall,' emphasizing a sense of the season. 5. Paulownia tree has another usefulness as a tree which adds an Ephemeral landscape. Therefore, the ancient people considered 'paulownia tree' that goes with 'the moon' the best, and enjoyed the quaint beauty of those two are juxtaposed. Also, 'paulownia tree' was utilized as a tree which adds an atmosphere of a rainy day, such as enjoying the sound of rain dropping on the 'paulownia tree', etc. The limitation of this study is that the research was performed being restricted to the translation among lots of Chinese references. Later-on task of research is the necessity of a more in-depth study through the discover of new historical sources and the accumulation of translation outcome.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.1
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• pp.45-50
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• 2002

The 'hands-on' craftsmanship of the 20th century has came and gone. Today, we are dealing with whole new, 'cerebral approach,' to concept and design with this new approach, design and function are very much dependant upon planning, sales, promotion, and the formative technique of the design industry. The innovative process of design constantly change as it reflects the needs and wants of society. It is and industry that constantly change as it reflects the needs and wants of society. It is and industry that constantly remakes and reshapes itself to suit current trend and outlook. The current idea being that consumers are looking for quality over quantity. Due to the 20th centuries dominant philosophy of functionalism, production intended to standardize the individual's purchasing choice. Aesthetic, or philosophic qualities played a second fiddle to the functional bias of a product, With production, Marketing, and research and development are integrated into the management process. This translates as good which include efficiency, quality, durability, and credibility an trademark and style. There is a definite 'post-modernist' movement and style in 21st century. Every possibility is available as the old boundaries of the 20th century are laid aside. There is a new, transformative quality to the current paradigm of design. The old "should" and "should not" of design no longerapplies. The integrated rative of design solves the usual disparity between aesthetic qualities and production. Design and profirability need not be stranger to one another. It can differentiate the image perceived of both enterprises and consumers by making use of integrated goods services. With an integrated system. both producers and designers win. While design gets full access to design in turn. All consumers make decisions based upon the evaluation of quality, service, and image ; even though it may not be a conscious decision to do so. Consumers are fully integrated human beings ; therefore producers who apply the new, integrated paradigmatic approach to concept, design, and production will reap the harvest of making a true relationship with individual buyer.

• Journal of Korean Society of Forest Science
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• v.95 no.3
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• pp.334-341
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• 2006

This study was to investigate the growth of planted red pine (Pinus densiflora S. et. Z.) seedling, soil properties and understory vegetation structure after fertilizer treatments [unfertilized plot (control), CF plot (Combination Fertilizer), UF plot (Urea Formaldehyde Fertilizer)] in a Pinus densiflora stand planted after the forest fires in Gosung, Gangwon province. The height growth rates of seedlings in four years were 264% in unfertilized, 404% in CF, and 388% in UF plots, respectively. The root collar diameters were increased 340% in unfertilized, 454% in CF, and 427% in UF plots, respectively. No significant changes occurred in soil total nitrogen and potassium ion ($K^+$) with the fertilization. However, available $P_2O_5$, content in the soil surface (0-15 cm) increased with the fertilizer application. Soil organic matter increased significantly with fertilizer treatments, while gradual decrease occurred in unfertilized plots. Sodium ion ($Na^-$) decreased in all sites. Soil pH, CEC, calcium ion ($Ca^{2+}$) and magnesium ion ($Mg^{2+}$) contents were not significantly different among treatments. Although Shannon's species diversity index and species richness in understory vegetation did not change with fertilizer treatments, vegetation cover rates in forest floor increased significantly with the fertilization. These results suggest that the increase of pine seedling growth and vegetation cover rates with fertilization could enhance soil stabilization in forest tire areas.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.2
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• pp.87-98
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• 2016

During the period between July 3 and 27 of 2009, water samples were collected from the Russian coast at a depth of 30m from 26 stations (including Ulleung and Japan basins) onboard the Russian survey vessel R/V Lavrentyev following 4 lines (D, R, E, and A). The samples were analyzed for nutrients and chlorophyll a contents. All parameters exhibited higher values in warm waters than in cold waters ($NH_4:1.8-fold$, $PO_4:1.8-fold$, $SiO_2:1.2-fold$, and chlorophyll-${\alpha}$:1.9-fold), except nitrates, which was 1.4-fold higher in cold waters than in warm waters. The horizontal distribution of ammonia, phosphate, and chlorophyll-${\alpha}$ was very similar to each other and showed the highest values in the waters near Russia, where a upwelling influence of cold current and bottom water prevails, while relatively low distribution was observed at the Ulleung Basin. On the other hand, nitrates showed the highest concentration at the Ulleung Basin, which is under the direct influence of the Tsushima warm water, and showed a gradual decrease northward. The N/P ratio showed the highest value in the Tsushima middle water, rather than in the North Korean Cold Water, the Tsushima Warm Water was the primary source of nitrate flow into the East Sea. However, the average concentration of phosphate in the warm waters was < $0.2{\mu}M$, thereby limiting phytoplankton growth, while a high concentration of phosphate in cold waters showed a direct correlation with chlorophyll-${\alpha}$. The results of principal component analysis for the identification of primary factors that influence the marine environment showed that principal component I was water temperature and principal component II was influenced chlorophyll-${\alpha}$ and nutrients. Therefore, Study area has greatest influenced by water temperature, and clearly distinct cold and warm water regions were observed in the East Sea.

• Korean Journal of Environmental Agriculture
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• v.23 no.1
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• pp.28-33
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• 2004

This study was conducted to how the effect of lime and humic acid on cadmium availability and ie uptake by plant grown in contaminated paddy soils with heavy metal. The treatment levels of lime were 2.5 and 5.0 ton/ha and that of humic acid were 1 and 2%. The contents of 0.1N HCl extractable Cd were reduced with lime and humic acid and were negatively correlated with CEC as well as soil pH. The sequential extraction procedure was used to fractionate the heavy metals in soils into the designated from exchangeable (0.5 M $KNO_3$) water soluble ($H_2O$), organically bound (0.5 M NaOH), carbonate (0.05 M $Na_{2-}$ EDTA) and sulfide/residual (4 M $HNO_3$). In soil amended with 2.5 ton/ha lime and 1% humic acia che- mical forms of Cd at tillering stage were predominant exchangeable + water soluble extractable Cd, whereas that at harvesting stage were predominant carbonate + sulfide/residual extractable Cd. The exchangeable forms of Cd in soil with lime and humic acid were negatively correlated with soil pH during the harvesting period. Total absorbed Cd of paddy rice tended to occur in the order of root > stem > leaf > brown rice. Cd contents of brown rice with lime and humic acid treatment were 0.09 and 0.08 mg/kg, respectively. That were lower than control, 0.20 mg/kg. It could be that treatment of lime and humic acid in polluted soil by heavy metals would reduce the uptake of heavy metals by piano and be a temporary method of reclamation at the highly heavy Metal contaminated soils.

• Analytical Science and Technology
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• v.24 no.3
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• pp.193-199
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• 2011

The purpose of this experiment is to evaluate the stability of products according to the storage methods, the period of use, and the diurnal variations through the short term stability experiment of recombinunt protein A (rProtein A) produced in AP Tech Co. That is, we investigated how long the stability of the products would last, when we used the samples frozen at $-20^{\circ}C$, which is one of the storage conditions of the produced rProtein A and then kept them refrigerated at $4^{\circ}C$. The experiment was conducted for 8 weeks and 6 experiment points were established. The experiment was done by thawing the samples frozen at $-20^{\circ}C$ at room temperature, and then refrigerating them at $4^{\circ}C$. In addition, experiments for endotoxin, bioburden, HPLC purity, and concentration were conducted. As a result of the experiment, 0.5 EU/mg endotoxin was detected both at the beginning and at the 8th week and bioburden was not analyzed. In the case of purity, it showed 99.23~99.90% at 210 nm (RSD% 0.23%) and 100% at 280 nm, which meant the change into other materials didn't happen and there was no material degradation characteristics. Finally, we also found the fact that the concentration stayed stable at 55.15 mg/mL (RSD% 0.55%) both at the beginning and at the end. From the experiment results, we were able to conclude that the stability at the condition to store rProtein A at 4 oC for 8 weeks was procured without producing microorganisms or having material degradation characteristics.