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오스템퍼링한 구상흑연주철(ADI)의 드릴 가공시 경도 및 현미경조직변화에 관한 연구
조규재,장우양,심재기,홍성오,김선진 한국공작기계학회 1999 한국생산제조학회지 Vol.8 No.1
This paper was carried out to know the influence of advanced austempered ductile cast iron (ADI) on the tool life and mechanical properties of drilling machinability. For manufactured method of ADI, the spheroidal graphite cast iron were austenized at 900℃ for 1 hour and then austempered for 2 hour at 370℃ in the salt bath. And interrelationship has been investigated between tool life and mechanical characteristics of specimen material on drilling condition when the ordinary and step-feed drilling are carried out to drill holes of specimens. Tensile strength and hardness of ADI decrease and elongation of ADI increases with the increase austempered temperature. It is known that about 2 times of tool life in the case of step-feed decreases compared with ordinary feed due to the high hardness of ADI and hardness ascribed to the fact that retained austenite beame to martensite state due to cutting heat in drilling. Under the constant feed rate 0.1㎜/rev relation between hardness and length of end tip after drilling can be formularized to Hv=788.46L^-0.096 for the cutting speed 6.1m/min.
교육용 소프트웨어 개발에 적합한 하이퍼미디어 시스템에 관한 연구
박성한,정혜윤,한민규,심진석 한양대학교 공학기술연구소 1993 공학기술논문집 Vol.2 No.1
This paper presents a back-end system of hypermedia authoring system for courseware development. For the design, repersentative hypertext reference models, the Dexter model and the HAM(Hypertext Abstract Machine) which belongs to Campbell & Goodman model were analyzed. Based on those models, data objects, attributes, and operations of back-end system were designed and implemented. Because the application area of this system is on computer based education, the path mechanism is enforced for the various educational strategies. In order to reduce the user disorientation and cognitive overheads in navigating hypernetwork, filtering, backtracking and history mechanism were implemented.
Anti-skin aging activity of eggshell membrane administration and its underlying mechanism
Sim Woo-Jin,Ahn Jisong,Lim Wonchul,손동주,Lee Eunjung,Lim Tae-Gyu 대한독성 유전단백체 학회 2023 Molecular & cellular toxicology Vol.19 No.1
Background There is active research on developing materials for improving skin function. Eggshell membrane (ESM) is one such raw material that is consumed as a functional food to support skin health. However, studies on the mechanism of improvement of skin function on ingestion of ESM are still lacking. Objectives To explore this mechanism of action, we conducted an ultraviolet (UV) irradiation study on a SKH-1 hairless mouse model. Feeding ESM was found to improve skin moisture and reduce wrinkles during 12 weeks of UVB irradiation. Results Oral administration of ESM restored moisture in the dorsal skin tissue of mice. In addition, oral ingestion of ESM also reversed the increased transepidermal water loss and reduction of mRNA expression of hyaluronic synthases induced by UVB irradiation. Furthermore, UVB irradiation-induced collagen degradation was inhibited, and the expression of the collagenase MMP was reduced in the ESM intake group compared to the control. These results confirmed that oral ingestion of the ESM has an anti-wrinkle effect. In addition, the mRNA expression of the antioxidant enzyme SOD1, which was reduced on UVB irradiation, was restored on ingestion of the ESM. Restoring the expression of antioxidant enzymes is a key strategy for improving skin function of the ESM. Conclusion Taken together, the findings from our study reveal the potential of ESM as a nutricosmetic material with antiwrinkle and skin moisturizing properties.
Determinants of Nicotine Dependence in Chronic Obstructive Pulmonary Disease
Sim, Yun Su,Lee, Jin Hwa,Kim, Ki Uk,Ra, Seung Won,Park, Hye Yun,Lee, Chang-Hoon,Kim, Deog Kyeom,Shin, Kyeong-Cheol,Lee, Sang Haak,Hwang, Hun Gyu,Ahn, Joong Hyun,Park, Yong Bum,Kim, Yu-Il,Yoo, Kwang Ha The Korean Academy of Tuberculosis and Respiratory 2017 Tuberculosis and Respiratory Diseases Vol.80 No.3
Background: Smoking cessation is the most powerful intervention to modify progress of chronic obstructive pulmonary disease (COPD), and nicotine dependence is one of the most important determinants of success or failure in smoking cessation. We evaluated nicotine dependence status and investigated factors associated with moderate to high nicotine dependence in patients with COPD. Methods: We included 53 current smokers with COPD in the Korean Obstructive Lung Disease II cohort enrolled between January 2014 and March 2016. Nicotine dependence was measured by using Fagerstrom test for nicotine dependence (FTND). Cognitive function was assessed by Korean version of Montreal Cognitive Assessment. Results: The median FTND score was 3, and 32 patients (60%) had moderate to high nicotine dependence. The median smoking amount was 44 pack-years, which was not related to nicotine dependence. Multiple logistic regression analysis revealed that high education status (odds ratio, 1.286; 95% confidence interval, 1.036-1.596; p=0.023), age <70 (odds ratio, 6.407; 95% confidence interval, 1.376-29.830; p=0.018), and mild to moderate airflow obstruction (odds ratio, 6.969; 95% confidence interval, 1.388-34.998; p=0.018) were related to moderate to high nicotine dependence. Conclusion: Nicotine dependence does not correlate with smoking amount, but with education level, age, and severity of airflow obstruction. Physicians should provide different strategies of smoking cessation intervention for current smokers with COPD according to their education levels, age, and severity of airflow obstruction.
Sim, Yeomoon,Choi, Jin Gyu,Gu, Pil Sung,Ryu, Byeol,Kim, Jeong Hee,Kang, Insug,Jang, Dae Sik,Oh, Myung Sook The Korean Society of Applied Pharmacology 2016 Biomolecules & Therapeutics(구 응용약물학회지) Vol.24 No.4
Cyperi Rhizoma (CR), the rhizome of Cyperus rotundus L., exhibits neuroprotective effects in in vitro and in vivo models of neuronal diseases. Nevertheless, no study has aimed at finding the neuroactive constituent(s) of CR. In this study, we identified active compounds in a CR extract (CRE) using bioactivity-guided fractionation. We first compared the anti-oxidative and neuroprotective activities of four fractions and the CRE total extract. Only the ethyl acetate (EA) fraction revealed strong activity, and further isolation from the bioactive EA fraction yielded nine constituents: scirpusin A (1), scirpusin B (2), luteolin (3), 6'-acetyl-3,6-diferuloylsucrose (4), 4',6' diacetyl-3,6-diferuloylsucrose (5), p-coumaric acid (6), ferulic acid (7), pinellic acid (8), and fulgidic acid (9). The activities of constituents 1-9 were assessed in terms of anti-oxidative, neuroprotective, anti-inflammatory, and anti-amyloid-${\beta}$ activities. Constituents 1, 2, and 3 exhibited strong activities; constituents 1 and 2 were characterized for the first time in this study. These results provide evidence for the value of CRE as a source of multi-functional neuroprotectants, and constituents 1 and 2 may represent new candidates for further development in therapeutic use against neurodegenerative diseases.
Input-Output Model에 의한 우리나라 호수의 영양상태 평가
沈有燮,朱忠男,문숙미,明奎男,柳明辰 서울시립대학교 산업기술연구소 1994 산업기술연구소논문집 Vol.2 No.-
The objectives of this research were to evaluate the trophic state using input-output models for some Korean lakes such as Daechung, Juam, Paldang and so on. Input-output models were designed to predict the trophic state of a lake and could be useful for water quality management in lakes. In this study, the applied empirical models were Vollenweider model, Larsen and Mercier model and Dillon model The results were as follows : 1. Total phosphorus to total nitrogen ratios in lakes were very high. It was estimated that lake productivity was influenced in accordance with the increase of phosphorus level. 2. A low correlation was found between the predicted total phosphorus concentration and chlorophyll-a concentrations. 3. The Present trophic states of the observed lakes might be evaluated to be eutrophic by the input-output models. In this respect a further study on the phosphorus removal of lake was needed.
Jin-Woo Park,Gyu-Jeong Sim,Dong-Chan Yang,Kyoung-Hwan Lee,Ji-Hea Chang,남기연,Hojun Lee,Bumsun Kwon 대한재활의학회 2016 Annals of Rehabilitation Medicine Vol.40 No.6
Objective To confirm a relationship between the pharyngeal response and bolus volume, and examine whether increasing the fluid bolus volume can improve penetration and aspiration for stroke dysphagic patients.Methods Ten stroke patients with a delayed pharyngeal response problem confirmed by a videofluoroscopic swallowing study (VFSS) were enrolled. Each subject completed two swallows each of 2 mL, 5 mL, and 10 mL of barium liquid thinned with water. The pharyngeal delay time (PDT) and penetration-aspiration scale (PAS) were measured and the changes among the different volumes were analyzed.Results PDTs were shortened significantly when 5 mL and 10 mL of thin barium were swallowed compared to 2 mL. However, there was no significant difference in PAS as the bolus volume increased. Conclusion The increased fluid bolus volume reduced the pharyngeal delay time, but did not affect the penetration and aspiration status.
Pain on injection with microemulsion propofol
Sim, Ji-Yeon,Lee, Soo-Han,Park, Do-Yang,Jung, Jin-Ah,Ki, Kyoung-Ho,Lee, Dong-Ho,Noh, Gyu-Jeong Blackwell Publishing Ltd 2009 British Journal of Clinical Pharmacology Vol.67 No.3
<P><B>WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT</B></P><P>• Aqueous free propofol in lipid emulsion elicits pain.</P><P>• No data on the incidence and severity of injection pain for Aquafol™ (Daewon Pharmaceutical Co., Ltd, Seoul, Korea), a lipid-free microemulsion propofol, are available.</P><P>• Two hypotheses involving plasma bradykinin generation have been proposed to explain propofol-induced pain; one implicates aqueous free propofol, the other implicates the lipid solvent.</P><P><B>WHAT THIS STUDY ADDS</B></P><P>• Microemulsion propofol produces more frequent and severe pain on injection, an effect that may be attributable to the high concentration of aqueous free propofol.</P><P>• There was no evidence that plasma bradykinin generation caused propofol-induced pain.</P><P>• In addition, agents known to prevent propofol-induced pain did not decrease aqueous free propofol concentrations.</P><P>AIMS</P><P>To evaluate the incidence and severity of injection pain caused by microemulsion propofol and lipid emulsion propofol in relation to plasma bradykinin generation and aqueous free propofol concentrations.</P><P>METHODS</P><P>Injection pain was evaluated in 147 patients. Aqueous free propofol concentrations in each formulation, and in formulation mixtures containing agents that reduce propofol-induced pain, were measured by high-performance liquid chromatography. Plasma bradykinin concentrations in both formulations and in their components mixed with blood sampled from six volunteers were measured by radioimmunoassays. Injection pain caused by 8% polyethylene glycol 660 hydroxystearate (PEG660 HS) was evaluated in another 10 volunteers.</P><P>RESULTS</P><P>The incidence of injection pain [visual analogue scale (VAS) >30 mm] caused by microemulsion and lipid emulsion propofol was 69.7 and 42.3% (<I>P</I> < 0.001), respectively. The median VAS scores for microemulsion and lipid emulsion propofol were 59 and 24 mm, respectively (95% confidence interval for the difference 12.5, 40.0). The aqueous free propofol concentration of microemulsion propofol was seven times higher than that of lipid emulsion propofol. Agents that reduce injection pain did not affect aqueous free propofol concentrations. Microemulsion propofol and 8% PEG660 HS enhanced plasma bradykinin generation, whereas lipid emulsion propofol and lipid solvent did not. PEG660 HS did not cause injection pain.</P><P>CONCLUSIONS</P><P>Higher aqueous free propofol concentrations of microemulsion propofol produce more frequent and severe pain. The plasma kallikrein–kinin system may not be involved, and the agents that reduce injection pain may not act by decreasing aqueous free propofol concentrations.</P>