http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
모비키즈: 통신전자파 노출과 어린이청소년의 뇌종양에 관한 환자 -대조군 연구 프로토콜
최경화,김동석,이정일,나영신,피지훈,안영환,권종화,이애경,최형도,하미나,Choi, Kyung-Hwa,Kim, Dong-Seok,Lee, Jung-il,Ra, Young-Shin,Phi, Ji Hoon,Ahn, Young Hwan,Kwon, Jong Hwa,Lee, Ae-Kyoung,Choi, Hyung-Do,Ha, Mina 한국환경보건학회 2015 한국환경보건학회지 Vol.41 No.3
Objectives: To introduce a protocol of Mobi-kids study which was aimed to examine an association between radiofrequency (RF) radiation exposure by mobile phone use and brain tumor risk in children and adolescents. Methods: The Mobi-kids study was a multinational matched case control study using a standardized protocol with the number of subjects targeted about 1,000 cases and 2,000 controls aged 10 to 24. In Mobi-Kids Korea, the source population was restricted to Seoul, Incheon, and Gyeonggi-do province. Eligible cases of primary brain tumor (glioma, meningioma, and others) were diagnosed from January 2012 to June 2015. Eligible controls were appendicitis patients operated during the study period. Two controls were matched on age, gender, and study region for 1 case. Information about pattern and history of mobile phone use and other covariates were obtained by face to face interview by trained interviewer. The Mobi-kids study has been involved in Mobi-expo as a validation study about mobile phone use, XGridmaster to localize tumor in the brain for RF energy calculation, and histological review for validation of diagnosis. Results: The Mobi-kids was the first and largest study in children and adolescents to estimate risk of brain tumor in association with the RF energy absorption in the brain estimated by mobile phone use. Forty-six-cases and 54 controls were collected as of September 2014 in Korea. Conclusions: The meaningful results of the study were expected because of the largest sample size, high validity of EMF exposure assessment as well as the susceptible study populationof children and adolescents.
최경화,박지희,서진호,Choi, Kyoung-Hwa,Park, Ji-Hee,Seo, Jin-Ho 국립문화재연구소 2010 保存科學硏究 Vol.31 No.-
Paper cultural heritages experience chemical and physical deterioration due to various factors including preservation environments and the property of paper materials1). Thus, it is important to develop optimal preservation and restoration methods for the damaged paper cultural heritages. Currently, lining is a popular treatment for the restoration of paper cultural heritages in Korea. Since lining paper is a layer of paper directly attached to the inside of cultural heritages for protection, understanding of the preservation properties of lining paper is primarily needed in order to devise the better preservation methods. The main material of lining paper is the paper mulberry, but additives such as chalk and white clay is sometimes used to enhance the preservation properties of lining paper. To date, the properties of the functional lining paper containing these additives have been not fully understood yet. In this study, dry heating aging at $105^{\circ}C$ and biological aging by the Aspergillus versicolor and Penicillium polonicum for the lining paper, which is made from paper mulberry and the chalk, are carried out to evaluate changes in their preservation properties by these aging factors. As a result, it is found that the functional lining paper containing 25.1% of chalk can control the growth of fungi, while the paper containing 32.7% of chalk do not show any protection effect. However, the functional lining paper added by chalk is more aged than the lining paper made from paper mulberry by dry heating accelerated aging.
최경화(Kyoung-Hwa Choi),서진호(Jin Ho Seo),이명구(Myoung-Ku Lee) 한국펄프·종이공학회 2017 펄프.종이技術 Vol.49 No.3
This study was conducted to investigate the changes in the HOCl absorption rate in the different tissue fabric and its effects on antibacterial rate against Klebsiella pneumoniae . HOCl solution was made by electrolysis of NaCl solution. As results, the absorption rate of HOCl solution into the basic tissue fabric increased with increasing cotton or rayon contents. Antibacterial activity against Klebsiella pneumoniae increased as HOCl concentration increased. Especially, the antibacterial activity of wet-tissue was 100% under the conditions of more than approximately 15 ppm of HOCl. However, it was found that antibacterial activity decreased with increasing the elapsed time after HOCl solution treatment.
CMC 첨가가 HwBKP의 그라인딩 특성에 미치는 영향
최경화(Kyoung-Hwa Choi),이재훈(Jae-Hun Lee),조병욱(Byoung-Uk Cho) 한국펄프·종이공학회 2016 펄프.종이技術 Vol.48 No.6
This study was conducted to investigate the effect of carboxymethyl cellulose (CMC) addition on the grinding characteristics of hardwood bleached kraft pulp (HwBKP). CMC was added into the pulp stock before grinding, and thereafter morphological properties and fibrillation characteristics of HwBKP during grinding were evaluated. It was found that CMC contributed to improve grinding of HwBKP. Fibrillation parameters including fibril area, fibril perimeter, water retention value, and pulp slurry viscosity were increased with the CMC addition. On the other hand, morphological properties including fiber width, fiber length, and curl were not influenced by the addition of CMC. It was speculated that CMC improved fibrillation of HwBKP during grinding because CMC acted as a lubricant and/or a thickener.
베타인-옥살산 공융용매 전처리가 MFC 제조효율에 미치는 영향
최경화(Kyoung-Hwa Choi),이재훈(Jae-Hoon Lee),이명구(Myoung-Ku Lee),류정용(Jeong-Yong Ryu) 한국펄프·종이공학회 2016 펄프.종이技術 Vol.48 No.6
This study was conducted to investigate the effects of deep eutectic solvent (DES) applied pre-treatment on the MFC manufacturing efficiency of hardwood bleached kraft pulp (HwBKP). DES was prepared by mixing of betaine and oxalic acid dihydrate (B and O), and the molar ratio of these two components mixtures was controlled to 1:1 (B:O=1:1). As results, grinding without BO DES pre-treatment shows the higher fiber fibrillation than that pre-treated with BO DES. And the energy that required to produce the MFC slurry having a same level of viscosity was slightly more consumped in case of BO DES pre-treatment than the case without pre-treatment. In other hand, the viscosity of the HwBKP fiber was decreased by BO DES pre-treatment but the viscosity of the HwBKP fiber treated with BO DES was less reduced by grinding than that without BO DES pretreatment. Namely, it was found that BO DES pre-treatment diminished the cellulose degradation by grinding.
위조문서 감별을 위한 현대 문서용지 특성 분석 ( II )
최경화(Kyoung-Hwa Choi),이재훈(Jae-Hoon Lee),류정용(Jeong-Yong Ryu) 한국펄프·종이공학회 2018 펄프.종이技術 Vol.50 No.4
In order to investigate the characteristics of modern paper, the fiber type and blending ratio of the domestic paper document samples for which the year of publication has been confirmed were examined. In the results, major fibers including softwood bleached kraft pulp (SwBKP), hardwood bleached kraft pulp (HwBKP) and bleached mechanical pulp (MP) were found to be used in modern paper. SwBKP has been steadily used up to 23% of the total fiber in modern paper to improve paper strength. Prior to 1980, MP was used as the main fiber furnish of the document paper. However, since 1980, it has changed from MP to HwBKP. This change is presumably due to the high lignin content of the mechanical pulp that causes fast color reversion. It also appears to be affected by increasing consumer demand for high quality such as high brightness and excellent printing property. However, some samples produced after 1980 still contain small amounts of MP fibers. Since most of the pulp used in Korean paper mills is imported pulp, a small amount of MP is sometimes used to reduce production costs. To increase the reliability of this study, we need to increase and to update data base continuously.
HYSTAP 장치를 이용한 펄프슬러리 내 첨가제들의 응집특성 평가
최경화(Kyoung-Hwa Choi),박정은(Jung Eun Park),조준형(Jun Hyung Cho) 한국펄프·종이공학회 2018 펄프.종이技術 Vol.50 No.2
Effects of molecular weight and charge density of a C-PAM (cationic polyacrylamide) used as a retention aid on the flocculation of the pulp slurry have been investigated by measuring a hydrostatic pressure using the hydrostatic pressure tester (HYSTAP). It was found that a hydrostatic pressure of pulp slurry was increased with increasing C-PAM dosages. Flocculation property between PCC (precipitated calcium carbonate) and pulp fibers in pulp slurry was improved by C-PAM addition. Especially, the flocculation property of pulp slurry increased with when higher molecular weights and charge densities of C-PAM were added. While, the formation of handsheets was decreased with the improvement of flocculation property of pulp slurry samples by addition of C-PAM. These decreasing tendency was corresponding with the increasing changes of hydrostatic pressure of pulp slurry samples in respect of molecular weights and charge densities of CPAM. The tensile strength of handsheets was slightly decreased by addition of C-PAM while the burst strength was not changed. The changes in tensile strength of handsheet according to a molecular weight of C-PAM were agreed with those of a hydrostatic pressure. But, the changes in respect with the charge density of C-PAM wasn’t corresponding with the change of a hydrostatic pressure. In other words, tensile strength of handsheet was most decreased by addition of the C-PAM having a lowest charge density.