• Title/Summary/Keyword: snap-through

Search Result 125, Processing Time 0.03 seconds

A shorted anode lateral MOS controlled thyristor with improved turn-off characteristics (턴-오프 특성이 향상된 Shorted Anode 수평형 MOS 제어 다이리스터)

  • 김성동;한민구;최연익
    • The Transactions of the Korean Institute of Electrical Engineers
    • /
    • v.45 no.4
    • /
    • pp.562-567
    • /
    • 1996
  • A new lateral MOS controlled thyristor, named Shorted Anode LMCT(SA-LMCT), is proposed and analyzed by a two-dimensional device simulation. The device structure employs the implanted n+ layer which shorts the p+ anode together by a common metal electrode and provides a electron conduction path during turn-off period. The turn-off is achieved by not only diverting the hole current through the p+ cathode short but also providing the electron conduction path from the n-base into the n+ anode electrode. In addition, the modified shorted anode LMCT, which has an n+ short junction located inside the p+ anode junction, is also presented. It is shown that the modified SA-LMCT enjoys the advantage of no snap-back behavior in the forward characteristics with little sacrificing of the forward voltage drop. The simulation result shows that the turn-off times of SA-LMCT can be reduced by one-forth and the maximum controllable current density may be increased by 45 times at the expense of 0.34 V forward voltage drop as compared with conventional LMCT. (author). 11 refs., 6 figs., 1 tab.

  • PDF

Activation of the cGMP/Protein Kinase G Pathway by Nitric Oxide Can Decrease TRPV1 Activity in Cultured Rat Dorsal Root Ganglion Neurons

  • Jin, Yun-Ju;Kim, Jun;Kwak, Ji-Yeon
    • The Korean Journal of Physiology and Pharmacology
    • /
    • v.16 no.3
    • /
    • pp.211-217
    • /
    • 2012
  • Recent studies have demonstrated that nitric oxide (NO) activates transient receptor potential vanilloid subtype 1 (TRPV1) via S-nitrosylation of the channel protein. NO also modulates various cellular functions via activation of the soluble guanylyl cyclase (sGC)/protein kinase G (PKG) pathway and the direct modification of proteins. Thus, in the present study, we investigated whether NO could indirectly modulate the activity of TRPV1 via a cGMP/PKG-dependent pathway in cultured rat dorsal root ganglion (DRG) neurons. NO donors, sodium nitroprusside (SNP) and S-nitro-N-acetylpenicillamine (SNAP), decreased capsaicin-evoked currents ($I_{cap}$). NO scavengers, hemoglobin and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (CPTIO), prevented the inhibitory effect of SNP on $I_{cap}$. Membrane-permeable cGMP analogs, 8-bromoguanosine 3', 5'-cyclic monophosphate (8bromo-cGMP) and 8-(4chlorophenylthio)-guanosine 3',5'-cyclic monophosphate (8-pCPT-cGMP), and the guanylyl cyclase stimulator YC-1 mimicked the effect of SNP on $I_{cap}$. The PKG inhibitor KT5823 prevented the inhibition of $I_{cap}$ by SNP. These results suggest that NO can downregulate the function of TRPV1 through activation of the cGMP/PKG pathway in peripheral sensory neurons.

In-plane buckling strength of fixed arch ribs subjected vertical distributed loading (수직 등분포 하중을 받는 고정 지점 포물선 아치 리브의 면내 좌굴 강도)

  • Moon, Ji Ho;Yoon, Ki Yong;Kim, Sung Hoon;Lee, Hak Eun
    • Journal of Korean Society of Steel Construction
    • /
    • v.17 no.4 s.77
    • /
    • pp.439-447
    • /
    • 2005
  • When arch ribs are subjected to vertical loading, they may buckle suddenly towards the in-plane direction. Therefore, the designer should consider their in-plane stability. In this paper, the in-plane elastic and inelastic buckling strength of parabolic, fixed arch ribs subjected to vertical distributed loading were investigated using the finite element method. A finite element model for the snap-through and inelastic behavior of arch ribs was verified using other researchers' test results. The ultimate strength of arch ribs was determined by taking into account their large deformation, material inelasticity, and residual stress. Finally, the finite element analysis results were compared with the EC3 design code.

Mechanical Characteristics of Shell Members Considering the Geometrical and Material Nonlinearity (기하 및 재료 비선형을 고려한 셸 부재의 역학적 특성)

  • Kim, Ki-Tae;Park, Beom-Hee;Kim, Da-Jin;Han, Sang-Eul
    • Journal of Korean Association for Spatial Structures
    • /
    • v.18 no.4
    • /
    • pp.31-39
    • /
    • 2018
  • This paper analyse the mechanical characteristics of geometrical and material nonlinearity behavior of cylindrical shell roofs subjected to a concentrated load. The shell elements were modeled using 'NISA2016' software as 3D general shell element and 3D composite shell element. The 3D shell element includes deformation due to bending, membrane, membrane-bending coupling and shear perpendicular to the grain effects is suited for modeling moderately thick or thin general shells and laminated composite shells. And The 3D composite shell element consists of a number of layers of perfectly bonded anisotropic and orthotropic materials. The purpose of this research is to analysis the load-deflection curves considering the combined geometric and material nonlinearity of cylindrical shells. In a shallowed cylindrical shell, snap-through curve can be found.

Characteristics of waterflood at low rate in low permeability sandstones based on the CT scanning

  • Mo, S.Y.;Lei, Q.;Lei, G.;Gai, S.H.;Liu, Z.K.
    • Geosystem Engineering
    • /
    • v.21 no.6
    • /
    • pp.344-351
    • /
    • 2018
  • It is reported that the flooding rate in low permeability sandstones is low and the oil recovery is hard to increase after water breakthrough. Understanding characteristics of waterflood is hence important for the recovery improvement. In this work, flooding tests on low permeability sandstones were conducted. The corresponding flooding characteristics were investigated by means of CT scanning and Nuclear Magnetic Resonance. Effects of irreducible water and different rates were also discussed in detail. Experimental results reveal a piston-like displacement at a low rate in low permeability samples. The saturation profile is steep and almost vertical to the forward direction. The results at a low rate confirm that once water broke through, increasing the flooding rate or flooding time can hardly reduce the remaining oil inside the sample. It is probably due to the high pore-throat ratio proven by rate-controlled mercury. Results also confirm that the presence of initial water enhanced sweep efficiency substantially. On one hand, because water had previously occupied the small pores, the subsequent oil can only invade relatively large pores and became more movable. On the other hand, stable collars can not form due to the steep front, which may suppress the snap-off.

Proposal of Makeup's Function on the Metaverse Digital Platform - Focusing on Zepeto - (메타버스 디지털 플랫폼의 메이크업 기능 제안 - 제페토를 중심으로 -)

  • Se Mi Nam;Eun Sil Kim
    • Fashion & Textile Research Journal
    • /
    • v.25 no.6
    • /
    • pp.739-744
    • /
    • 2023
  • With the popularization of 5G networks and the development of AI (artificial intelligence) technology, Metaverse, which creates production capacity by combining virtual space and reality, is attracting attention. In this study, we searched for makeup applications with more than 100 million downloads from October 11, 2020 to November 3, 2020 through the Google Play Store. As a result of the search, four applications were found: YouCam Makeup, YouCam Perfect, Beauty Plus, and Sweet Snap. Based on the functions provided by the four applications, we attempted to suggest makeup functions applicable to Zepeto's avatar. Functions for the eyes (eyeliner, eyelashes, mascara, eye shadow, eye shape, eyebrow shape, lenses, double eyelids), functions for the nose (nose shape), functions for the mouth (lipstick, lip shape, smile function) ) Functions corresponding to the facial contour (contour, skin foundation, blusher, shading, highlighter, face painting, theme makeup) and functions corresponding to the body (body adjustment) were proposed. This study is the first in the beauty field to propose a method of applying the functions of the Metaverse platform as the importance of digital platforms is highlighted, and is the first to propose a makeup function applied to the Metaverse so that it can be used as important basic data in the future.

Involvement of Peroxynitrite in NO Donor-Induced HO-1 Expression in Rat Articular Chondrocytes (흰쥐 관절연골세포에서 NO donor에 의해 유도된 HO-1 발현에서 peroxynitrite의 관련성 연구)

  • Song, Ju-Dong;Kim, Kang-Mi;Kim, Jong-Min;Yoo, Young-Hyun;Park, Young-Chul
    • Journal of Life Science
    • /
    • v.21 no.4
    • /
    • pp.486-493
    • /
    • 2011
  • Nitric oxide (NO) donors are a potent inducer of heme oxygenase-1 (HO-1). However, it is unclear whether or not HO-1 expression induced by NO donors is a direct consequence of NO released by NO donors. Here, we investigated the effects of NO donors on the expression of HO-1 in primary rat articular chondrocytes. NO donors (SIN-1, SNAP, and SNP) significantly induced the accumulation of HO-1 protein accompanied by an increase in HO-1 mRNA. NO donor-induced HO-1 expression exerted cytoprotection against NO and/or superoxide-induced cell death. Guanylate cyclase signaling was not associated with Nrf2 and HO-1 expression in NO donor-treated chondrocytes. Interestingly, NO scavenger carboxy-PTIO and SOD mimetic TEMPOL markedly inhibited NO donor-induced HO-1 expression in chondrocytes. In addition, NO donor-induced HO-1 expression was completely abrogated by the peroxynitrite scavenger MnTBAP. Since peroxynitrite can be physiologcally formed in the cell through reaction of NO with superoxide, we analyzed whether or not peroxynitrite could directly induce HO-1 expression in chondrocytes. Peroxynitrite treatment in chondrocytes evoked doseand time-dependent Nrf2 and HO-1 expression. These results indicate that HO-1 expression induced by NO donors in rat articular chondrocytes is due to NO-mediated peroxynitrite rather than NO.

Effect of Uniconazole and Silver Thiosulfate Treatment on Reduction of Ozone Injury in Snap Bean Plants (Uniconazole과 Silver Thiosulfate 처리(處理)가 강남콩의 오존피해(被害) 경감(輕減)에 미치는 효과(效果))

  • Ku, Ja Hyeong;Won, Dong Chan;Cho, Jeong Hee;Shin, Dae Shik
    • Korean Journal of Agricultural Science
    • /
    • v.19 no.2
    • /
    • pp.161-169
    • /
    • 1992
  • Studies were conducted to examine the effects of single or combined treatment of uniconazole [(E)-1-(4-chlorophenyl)-4, 4-dimethyl 2(1, 2,-4-triazol-1-yl)-1-penten-3-ol)] and silver thiosulfate (STS) on reducing ozone injury to snap beans (Phaseolus vulgaris L. 'Strike'). Two weeks after seeding, plants were given a soil drench of uniconazole(XE-1019) solution at concentrations of 0.001, 0.005 and 0.025 mg/pot, and then two days prior to ozone fumigation, 0.3 and 0.6 mM STS containing 0.01% Tween-20 were also sprayed. Uniconazole was effective in providing protection against ozone injury through increase activities of free radical scavengers such as superoxide dismutase (SOD) and peroxidase (POD) as well as the increase of chlorophyll content and stomatal resistance resulted from plant growth retardation. The phytoprotective effects of STS seemed to be related to its properly of blocking the ethylene action and increasing activities of SOD and POD. Even at low concentrations, a combined treatment with uniconazole drench, STS spray significantly reduced ozone injury compared to single application.

  • PDF

Hyaluronic Acid Enhances the Dermal Delivery of Anti-wrinkle Peptide via Increase of Stratum Corneum Fluidity (히알루론산의 각질 유동성 향상을 통한 주름 개선 펩타이드 피부 흡수 촉진)

  • Kim, Yun-Sun;Kim, Daehyun;Kim, Yumi;Park, Sun-Gyoo;Lee, Cheon-Koo;Kang, Nae-Gyu
    • Journal of the Society of Cosmetic Scientists of Korea
    • /
    • v.44 no.4
    • /
    • pp.447-453
    • /
    • 2018
  • Acetyl hexapeptide 8 (AH8) is a synthetic peptide for anti-wrinkle cosmetics ingredient. It was developed as a mimetic of botox, patternd after N -terminal end of the protein synatosomal-associated protein 25 (SNAP25), a substrate of botulinum toxin. While AH8 has good efficacy and safety profiles, the permeation through the skin is poor. Therefore, we tried to enhance the transdermal delivery of AH8 by using of hyaluonic acid (HA), a linear polysaccharide of N-acetyl glucosamine and glucuronic acid. To investigate the effect of HA on AH8 penetration, we analyzed paraffin sections of $Micropig^{(R)}$ skin. Fluorescence labeled AH8 was applied to micropig skin with or without HA. The absorption of AH8 was limited to the stratum corneum (SC) without HA. On the other hand, AH8 penetrated to the dermis with HA. Especially, low molecular weight HA (5 kDa) was most efficient compared to 500 kDa HA and 2000 kDa HA. Experiments using fourier-transform infrared (FTIR) spectroscopy revealed that lower molecular weight HA had a tendency to increase the fluidity of the SC lipids more, which means enhancing the skin penetration. Therefore, HA could be expected to enhance the anti-wrinkle effect of AH8.

Early Estimation of Rice Cultivation in Gimje-si Using Sentinel-1 and UAV Imagery (Sentinel-1 및 UAV 영상을 활용한 김제시 벼 재배 조기 추정)

  • Lee, Kyung-do;Kim, Sook-gyeong;Ahn, Ho-yong;So, Kyu-ho;Na, Sang-il
    • Korean Journal of Remote Sensing
    • /
    • v.37 no.3
    • /
    • pp.503-514
    • /
    • 2021
  • Rice production with adequate level of area is important for decision making of rice supply and demand policy. It is essential to grasp rice cultivation areas in advance for estimating rice production of the year. This study was carried out to classify paddy rice cultivation in Gimje-si using sentinel-1 SAR (synthetic aperture radar) and UAV imagery in early July. Time-series Sentinel-1A and 1B images acquired from early May to early July were processed to convert into sigma naught (dB) images using SNAP (SeNtinel application platform, Version 8.0) toolbox provided by European Space Agency. Farm map and parcel map, which are spatial data of vector polygon, were used to stratify paddy field population for classifying rice paddy cultivation. To distinguish paddy rice from other crops grown in the paddy fields, we used the decision tree method using threshold levels and random forest model. Random forest model, trained by mainly rice cultivation area and rice and soybean cultivation area in UAV image area, showed the best performance as overall accuracy 89.9%, Kappa coefficient 0.774. Through this, we were able to confirm the possibility of early estimation of rice cultivation area in Gimje-si using UAV image.