하이브리드 여자방식을 이용한 SRM 의 진동 소음 저감

김창섭,이상훈,안진우 경성대학교 공학기술연구소 2000 공학기술연구지 Vol.7 No.-

The simple motor construction and low cost, fault tolerant power electronic drive has made the switched reluctance drive a strong contender for many applications. But the switched reluctance drive does exhibit higher levels of vibration and acoustic noise than most competing drives. The main source of vibration in the switched reluctance drive is generated by rapid change of radial force when phase current is exthinguished by commutation action. In this paper, a hybrid excitation method is proposed to reduce vibration and acoustic noise of the switched reluctance drive. The hybrid excitation has 2-phase excitation by long dwell angle as well as conventional 1-phase excitation. The vibration and acoustic noise are reduced because the scheme reduces abrupt change of excitation level by distributed and balanced excitation.

전기 지게차 구동용 1.2kW급 SRM

김창섭,이상훈,안진우 경성대학교 공학기술연구소 2000 공학기술연구지 Vol.7 No.-

An SRM for a pallet truck drive is developed and tested. The drive system has to operate with low voltage and high current, and has to have the characteristics of DC series motor. The small size, ruggedness high efficiency make it possible to replace with DC motor. Test results show that pallet truck with SRM has better performance characteristics than that of the DC motor's.

서울의 Penicillinase Producing Neisseria Gonorrhoeae 발생빈도(1994)

김재홍,안진균,정성재,김영태,김중환,김시영,이석종,이홍렬,서호석,김경훈,권혁진,정우권,고우석,이용석,안필수,오준규,오용섭 대한화학요법학회 1996 대한화학요법학회지 Vol.14 No.1

Background : In recent years gonorrhoea has been panendemic and remains one of the most common Sexually Transmitted Diseases in the world, especially in developing countries. Objective & Method : For the detection of a more effective therapeutic regimen and assessing the prevalence of Penicillinase Producing Neisseria Gonorrhoeae(PPNG), Ive have been trying to study the patients who have visited the VD Clinic of Choong-Ku Public Health Center in Seoul since 1980 by means of the chromogenic cephalosporin method. Results : In 1994, 168 strains of N. gonorrhoeae were isolated, among which 109 (64,9% ) were PPNG. Conclustion : Our results suggests that the prevalence of PPNG in Seoul is still increasing.

High rate capabilities induced by multi-phasic nanodomains in iron-substituted calcium cobaltite electrodes

Ko, Young-Dae,Kang, Jin-Gu,Choi, Kyung Jin,Park, Jae-Gwan,Ahn, Jae-Pyoung,Chung, Kyung Yoon,Nam, Kyung-Wan,Yoon, Won-Sub,Kim, Dong-Wan Royal Society of Chemistry 2009 Journal of materials chemistry Vol.19 No.13

<P>Two-dimensional (2-D) nanoplates of iron-substituted calcium cobaltite (Ca<SUB>3</SUB>Co<SUB>3</SUB>FeO<SUB>9</SUB>) are synthesized through a simple citrate-gel method. The lithium electroactivity of Ca<SUB>3</SUB>Co<SUB>3</SUB>FeO<SUB>9</SUB> demonstrates that this is an applicable active anode material. In this study, we focus on the reversible conversion process and internally multi-phasic, nanostructured character occurring in Ca<SUB>3</SUB>Co<SUB>3</SUB>FeO<SUB>9</SUB> nanoplates. Moreover, we demonstrate that in-situ formation of active/inactive nanocomposite improves the conversion reaction kinetics by accommodating the large volume changes during lithium uptake and removal, thereby achieving outstanding rate capabilities.</P> <P>Graphic Abstract</P><P>Two-dimensional nanoplates of iron-substituted calcium cobaltite (Ca<SUB>3</SUB>Co<SUB>3</SUB>FeO<SUB>9</SUB>) synthesized through a simple citrate-gel method are found to be an active anode material. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b817120c'> </P>

Evidence of reversible oxygen participation in anomalously high capacity Li- and Mn-rich cathodes for Li-ion batteries

Muhammad, Shoaib,Kim, Hyunchul,Kim, Yunok,Kim, Donghwi,Song, Jay Hyok,Yoon, Jaegu,Park, Jin-Hwan,Ahn, Sung-Jin,Kang, Sun-Ho,Thackeray, Michael M.,Yoon, Won-Sub Elsevier 2016 Nano energy Vol.21 No.-

<P><B>Abstract</B></P> <P>The reaction mechanism of a high capacity lithium- and manganese-rich metal oxide, 0.4Li<SUB>2</SUB>MnO<SUB>3</SUB>–0.6LiMn<SUB>0.5</SUB>Ni<SUB>0.5</SUB>O<SUB>2</SUB>, has been investigated at the atomic level. High-resolution synchrotron X-ray powder diffraction (HRPD) and X-ray absorption spectroscopy (XAS) were used, respectively, to evaluate the electrochemical charge and discharge reactions in terms of local and bulk structural changes, and variations in the oxidation states of the transition metal ions. Ni K-edge XAS data indicate the participation of nickel in reversible redox reactions, whereas Mn K-edge absorption spectra show that the manganese ions do not participate in the electrochemical reactions. Rietveld refinements of the oxygen occupancy during charge and discharge provide evidence of reversible oxygen release and re-accommodation by the host structure; this unique oxygen participation is likely the main reason for the anomalously high capacity of these electrodes. The HRPD data also show that during the early cycles, characteristic peaks of the Li<SUB>2</SUB>MnO<SUB>3</SUB> component disappear when charged to 4.7V, but reappear on discharge to 2.5V, consistent with a reversible lithium and oxygen extraction process. The results provide new insights into the charge compensation mechanisms that occur when high capacity, lithium- and manganese-rich electrode materials are electrochemically cycled – a topic that is currently being hotly debated in the literature.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Anomalous high capacity of Li- and Mn-rich electrodes has been probed by HRPD and XAS. </LI> <LI> Reversible oxygen release and re-accommodation by the host structure accounts, at least in part, for the unusual high capacity. </LI> <LI> The Li<SUB>2</SUB>MnO<SUB>3</SUB> character of Li- and Mn-rich metal oxide structures is preserved during the initial cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Correlations of 3T DCE-MRI Quantitative Parameters with Microvessel Density in a Human-Colorectal-Cancer Xenograft Mouse Model

Ahn, Sung Jun,An, Chan Sik,Koom, Woong Sub,Song, Ho-Taek,Suh, Jin-Suck The Korean Society of Radiology 2011 KOREAN JOURNAL OF RADIOLOGY Vol.12 No.6

<P><B>Objective</B></P><P>To investigate the correlation between quantitative dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) parameters and microvascular density (MVD) in a human-colon-cancer xenograft mouse model using 3 Tesla MRI.</P><P><B>Materials and Methods</B></P><P>A human-colon-cancer xenograft model was produced by subcutaneously inoculating 1 × 10<SUP>6</SUP> DLD-1 human-colon-cancer cells into the right hind limbs of 10 mice. The tumors were allowed to grow for two weeks and then assessed using MRI. DCE-MRI was performed by tail vein injection of 0.3 mmol/kg of gadolinium. A region of interest (ROI) was drawn at the midpoints along the z-axes of the tumors, and a Tofts model analysis was performed. The quantitative parameters (K<SUP>trans</SUP>, K<SUB>ep</SUB> and V<SUB>e</SUB>) from the whole transverse ROI and the hotspot ROI of the tumor were calculated. Immunohistochemical microvessel staining was performed and analyzed according to Weidner's criteria at the corresponding MRI sections. Additional Hematoxylin and Eosin staining was performed to evaluate tumor necrosis. The Mann-Whitney test and Spearman's rho correlation analysis were performed to prove the existence of a correlation between the quantitative parameters, necrosis, and MVD.</P><P><B>Results</B></P><P>Whole transverse ROI of the tumor showed no significant relationship between the MVD values and quantitative DCE-MRI parameters. In the hotspot ROI, there was a difference in MVD between low and high group of K<SUP>trans</SUP> and K<SUB>ep</SUB> that had marginally statistical significance (<I>ps</I> = 0.06 and 0.07, respectively). Also, K<SUP>trans</SUP> and K<SUB>ep</SUB> were found to have an inverse relationship with MVD (<I>r</I> = -0.61, <I>p</I> = 0.06 in K<SUP>trans</SUP>; <I>r</I> = -0.60, <I>p</I> = 0.07 in K<SUB>ep</SUB>).</P><P><B>Conclusion</B></P><P>Quantitative analysis of T1-weighted DCE-MRI using hotspot ROI may provide a better histologic match than whole transverse section ROI. Within the hotspots, K<SUP>trans</SUP> and K<SUB>ep</SUB> tend to have a reverse correlation with MVD in this colon cancer mouse model.</P>

Energy-Band-Engineered Unified-RAM (URAM) Cell on Buried <tex> $\hbox{Si}_{1 - y}\hbox{C}_{y}$</tex> Substrate for Multifunctioning Flash Memory and 1T-DRAM

Jin-Woo Han,Seong-Wan Ryu,Chung-Jin Kim,Sung-Jin Choi,Sungho Kim,Jae-Hyuk Ahn,Dong-Hyun Kim,Kyu Jin Choi,Byung Jin Cho,Jin-Soo Kim,Kwang Hee Kim,Gi-Sung Lee,Jae-Sub Oh,Myeong-Ho Song,Yun Chang Park,Je IEEE 2009 IEEE transactions on electron devices Vol.56 No.4

<P>A band-offset-based unified-RAM (URAM) cell fabricated on a Si/Si<SUB>1-y</SUB>C<SUB>y</SUB> substrate is presented for the fusion of a nonvolatile memory (NVM) and a capacitorless 1T-DRAM. An oxide/nitride/oxide (O/N/O) gate dielectric and a floating-body are combined in a FinFET structure to perform URAM operation in a single transistor. The O/N/O layer is utilized as a charge trap layer for NVM, and the floating-body is used as an excess hole storage node for capacitorless 1T-DRAM. The introduction of a pseudomorphic SiC-based heteroepitaxial layer into the Si substrate provides band offset in a valence band. The FinFET fabricated on the energy-band-engineered Si<SUB>1-y</SUB>C<SUB>y</SUB> substrate allows hole accumulation in the channel for 1T-DRAM. The band-engineered URAM yields a cost-effective process that is compatible with a conventional body-tied FinFET SONOS. The fabricated URAM shows highly reliable NVM and high-speed 1T-DRAM operations in a single memory cell.</P>

The influence of a continuous increase in thickness of opaque-shade composite resin on masking ability and translucency

An, Jung-Sub,Son, Ho-Hyun,Qadeer, Sarah,Ju, Sung-Won,Ahn, Jin-Soo Informa Healthcare 2013 Acta odontologica scandinavica Vol.71 No.1

<P><B><I>Objectives.</I></B> This study was conducted to determine the minimum thickness of opaque-shade composite resin required to mask discolored tooth structures or darkness of the oral cavity and to determine the effect of the brand and shade of composite resins on masking ability and translucency. <B><I>Materials and methods.</I></B> Discs and beveled specimens were manufactured using six opaque-shade light-curing composite resins (Charisma, Heraeus Kulzer; Estelite Sigma Quick, Tokuyama; Gradia Direct Anterior, GC). The discolored tooth structures and darkness of the oral cavity were reproduced using background tiles. The disc specimen colors were measured using a spectroradiometer by increasing the thickness of the beveled specimens on the backing by 0.05 mm in series, and color difference (ΔE*<SUB>ab</SUB>) and translucency parameter (TP) were calculated. <B><I>Results.</I></B> The thicknesses of opaque-shade composite resins that masked the C4 shade and black backings were 0.80-1.45 and 1.85-2.00 mm, respectively. Overall, the ΔE*<SUB>ab</SUB> and TP values decreased as the thickness of the opaque-shade composite resins increased. When the shades of the composite resins were identical, the TP decreased in the order of Charisma, Estelite Sigma Quick and Gradia Direct Anterior. When the brand was fixed, the TP was higher in the OA3 shade than in the OA2 shade. A significant correlation was seen between ΔE*<SUB>ab</SUB> and TP (<I>p</I> < 0.05). <B><I>Conclusions.</I></B> The brands and shades of the composite resins were shown to have a clear effect on TP, but an inconsistent tendency for ΔE*<SUB>ab</SUB>.</P>

Nondestructive Measurement of Paprika (Capsicum annuum L.) Internal Electrical Conductivity and Its Relation to Environmental Factors

Hyun Jun Park,Jin Hee Park,Kyoung Sub Park,Tae In Ahn,Jung Eek Son 한국원예학회 2018 원예과학기술지 Vol.36 No.5

The electrical properties of plants represent physiological activities including water and ion transport in their stems. Therefore, monitoring electrical conductivity in plants (EC<SUB>p</SUB>) can be used to detect plant responses to changes in environmental conditions. Stable measurement of internal EC<SUB>p</SUB> was developed to evaluate the relationship between the EC<SUB>p</SUB> and environmental factors. Two electrodes with three needles were inserted into each side of paprika stems to monitor paprika EC<SUB>p</SUB> in response to the environmental factors of temperature, irradiation, and relative humidity. The EC<SUB>p</SUB> was positively correlated with irradiation and temperature (R² = 0.642 and 0.815, respectively), but negatively correlated with relative humidity (R² = -0.416). The EC<SUB>p</SUB> was higher in May than in February due to size differences in the vascular bundle sheaths as well as changes in irradiation and temperature. The EC<SUB>p</SUB> was predicted using a regression equation that described environmental data, and the predicted results corresponded well to plant measurements. The EC<SUB>p</SUB> was higher during the day than at night, which was attributed to higher daytime water content in the stems.

Antioxidant Effect of Secondary Metabolites from Ligularia fischeri Leaves

Jin Kyu Kim(김진규),Changon Seo(서찬곤),Seong Su Hong(홍성수),Jin Gwan Kwon(권진관),You Jin Hong(홍유진),Jae Yeon Lee(이재연),Eun-Kyung Ahn(안은경),Joa Sub Oh(오좌섭) 한국약용작물학회 2013 한국약용작물학회 학술대회논문집 Vol.2013 No.2