http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Consideration of Diluents Selection and Input Amounts of the Hunter Process for Tantalum Production
Jae‑Jin Sim,Sang‑Hoon Choi,Yong‑Kwan Lee,Sung Gue Heo,Taek‑Soo Kim,Seok‑Jun Seo,Kyoung‑Tae Park 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7
Tantalum (Ta) is a heavy refractory metal with an atomic weight of 180.95 g/mol, a density of 16.6 g/cm3, and a high meltingpoint of 3017 °C. With its refractory characteristics, it shows excellent chemical and physical stability as well as corrosionand heat resistance at elevated temperatures. The demand for Ta metal and related compounds is increasing with the expansionof the electronics and chemical industries. The Hunter process was proven to be effective in producing Ta powder in1953. Hunter proposed a method in which potassium heptafluorotantalate (K2TaF7) was reduced by sodium (Na). Thus far,this process has been the primary commercial method to produce Ta powder. In this study, quantitative differences wereanalyzed for diluent selection. Additionally, consideration was given to changes in the caloric value depending on the inputamount of diluents. Finally, the optimum material input and the properties of the prepared Ta were analyzed. Stoichiometricratios of K2TaF7(1 mol), NaCl (6.2–6.7 mol), Na (5–7 mol) were weighed, to perform a metallothermic reduction reaction. After the reaction, the tantalum powder was recovered and the flush process was carried out. After that, it was dried in avacuum atmosphere. Physical properties such as oxygen concentration, PSA, ICP-OES, and XRD of powder were conductedto evaluate the characteristics of Ta powder that was finally manufactured.
허준,양성원,양필중,고재웅 朝鮮大學校 附設 醫學硏究所 2007 The Medical Journal of Chosun University Vol.32 No.2
Purpose: Persistent pupillary membrane(PPM) can be classified as four types by means of its morphology. Type 2, which is attached to the lens, is very rare and can cause visual disability. We report 3 cases of type 2 PPM that shows a good visual acuity and cosmetic improvement after removal. Methods: We chose 3 female who showed a poor visual outcome and abnormal shaped pupil since a child. All of 3 case could be examined a hyperplastic persistent pupillary membrane by slit lamp biomicroscopy. Treatment was a surgical removal of PPM, and a surgical removal of PPM and cataract operation in one case of PPM with cataract. Results: All of 3 patient showed a good visual acuity and cosmetic improvement, Conclusion: Surgical management should be also considered to good visual acuity and cosmetic improvement to PPM observed in adult eye.
임재규(Jae Kyoo Lim),이상용(Sang Yong Lee),송준희(Jun Hee Song),최준용(Jun Yong Choi),김효진(Hyo Jin Kim),김연직(Yon Jig Kim),국중하(Jung Wha Guk),허남준(Nam Jun Heo) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.10
In recent years there has been a growing interest for the use of natural fibers in composite applications due to their low cost, environmental friendliness, and good mechanical properties. The purpose of this study is to determine the characteristic of bending strength on bamboo fiber reinforced polymer composites. The parameters of RTM process depend on the weight ratio of bamboo fiber and resin, the number of bamboo ply and amount of hardening agent. Besides the existence of pore in composites according to vacuum time investigated a effect on mechanical properties of reinforced polymer composites. Test result shows that bending strength was a maximum(approximately 850kgf/㎠) value when composite thickness was 6mm and weight ratio of resin was 13%.
Remifentanil-Propofol Sedation as an Ambulatory Anesthesia for Carpal Tunnel Release
Lee, Jae-Jun,Hwang, Sung-Mi,Jang, Ji-Su,Lim, So-Young,Heo, Dong-Hwa,Cho, Yong-Jun The Korean Neurosurgical Society 2010 Journal of Korean neurosurgical society Vol.48 No.5
Objective : This prospective study evaluated the use of continuous sedation using propofol and remifentanil when carpal tunnel release (CTR) was performed under local anesthesia. Methods : We sedated 60 patients undergoing CTR using local anesthesia with remifentanil at loading and continuous doses of $0.5\;{\mu}g\;kg^{-1}$ and $0.05\;{\mu}g\;kg^{-1}min^{-1}$, respectively, and propofol, using a target controlled infusion (TCI) pump set to a target of $2\;{\mu}g\;mL^{-1}$ (group A), or with the same drug doses except that the continuous remifentanil dose was $0.07\;{\mu}g\;kg^{-1}min^{-1}$ (group B) or $0.1\;{\mu}g\;kg^{-1}min^{-1}$ (group C). Results : In group B, the levels of pain when local anesthetics were administered (p = 0.001), intraoperative pain (p < 0.001) and anxiety (p = 0.001) were significantly lower than those of group A. Furthermore, the incidence of adverse events, including desaturation (p < 0.001) and vomiting (p = 0.043), was significantly lower in group B than in group C. Conclusion : Continuous sedation using an appropriate dose of remifentanil and propofol can be used as safe, efficacious ambulatory anesthesia in cases of CTR under local anesthesia, performed using only 2 mL of local anesthetic, with a high degree of patient satisfaction.
Role of FOXO3a in Regulation of DNA Double Strand Break Repair Activity During Aging
Jee-In Heo,Jae-Hyun Kim,Seong-Hoon Park,Hong-Jun Kang,Yoo-Jin Jung,Sung Chan Kim,Jaebong Kim,Jae-Bong Park,Jae-Yong Lee(이재용) 한국실험동물학회 2010 한국실험동물학회 학술발표대회 논문집 Vol.2010 No.2
Non homologous end joining (NHEJ) activity is known to be major double strand break DNA repair acivity in mammals and to be decreased during cellular aging even though their molecular mechanism remains still unknown. NHEJ activity was also decreased in aged tissue of mouse. Caloric restriction rescued decreased NHEJ activity in aged tissued. The level and activity of FOXO3a was also decreased in aged cells and tissues. In order to investigate the relationship between NHEJ activity and FOXO3a in cellular aging, we tested the levels of NHEJ factors and FOXO3a during cellular aging of human embryonic fibroblast (HEF). The protein levels of XRCC4, a NHEJ factor was decreased as well as NHEJ activity and FOXO3a level. To test whether NHEJ activity is dependent on XRCC4 and FOXO3a, we overexpressed XRCC4 and FOXO3a in old HEF by transfecting wildtype expression vector of XRCC4 or FOXO3a. The result showed that NHEJ activity was increased by overexpression of either XRCC4 or FOXO3a. Interestingly, the level of XRCC4 was also increased by overexpression of FOXO3a, suggesting that XRCC4 could be a target gene of FOXO3a. A reporter construct containing XRCC4 promoter and luciferase gene was used to test whether XRCC4 is regulated transcriptionally by FOXO3a. The result showed that luciferase activity was increased by FOXO3a overexpression in old HEF. Further, CHIP assay confirmed that FOXO3a interacts more tightly to XRCC4 promoter in young HEF. Immunohistochemical analysis using FOXO3a in mouse brain showed that aged hippocampus and cortex expressed low level of FOXO3a. Immuno blotting using FOXO3a in mouse brain showed that FOXO3a, XRCC4 and NHEJ were down-regulated in aged tissues. Taken together, the result demonstrated that the XRCC4 is transcriptionally regulated by FOXO3a during aging.