• Title/Summary/Keyword: No Tail Current

Search Result 15, Processing Time 0.025 seconds

Electrical Characteristics of Novel LIGBT with p Channel Gate and p+ Ring at Reverse Channel Structure (p+링과 p 채널 게이트를 갖는 역채널 LIGBT의 전기적인 특성)

  • Gang, Lee-Gu;Seong, Man-Yeong
    • The Transactions of the Korean Institute of Electrical Engineers C
    • /
    • v.51 no.3
    • /
    • pp.99-104
    • /
    • 2002
  • lateral insulated gate bipolar transistors(LIGBTs) are extensively used in high voltage power IC application due to their low forward voltage drops. One of the main disadvantages of the LIGBT is its scow switching speed when compared to the LDMOSFET. And the LIGBT with reverse channel structure is lower current capability than the conventional LIGBT at the forward conduction mode. In this paper, the LIGBT which included p+ ring and p-channel gate is presented at the reverie channel structure. The presented LIGBT structure is proposed to suppress the latch up, efficiently and to improve the turn off time. It is shown to improve the current capability too. It is verified 2-D simulator, MEDICI. It is shown that the latch up current of new LIGBT is 10 times than that of the conventional LIGBT Additionally, it is shown that the turn off characteristics of the proposed LIGBT is i times than that of the conventional LIGBT. It is net presented the tail current of turn off characteristics at the proposed structure. And the presented LIGBT is not n+ buffer layer because it includes p channel gate and p+ ring.

GEOTAIL SPACECRAFT OBSERVATIONS OF NEAR-TAIL DIPOLARIZATION AND PLASMA FLOW DURING THE SUBSTORM EXPANSION

  • Lee, D.Y.;Min, K.W.;Lee, E.S.
    • Journal of Astronomy and Space Sciences
    • /
    • v.17 no.2
    • /
    • pp.141-146
    • /
    • 2000
  • Some observational features on the July 5, 1995 substorm event are presented using the data from the Geotail satellite which was located at near-Earth plasma sheet, ${X}_{GSE}$$-9.6R_{E}$, and quite close to the onset sector. Near-tail magnetic field reveals the typical dipolarizations starting ar ∼ 11-4 UT until ∼ 1113 UT. During the interval, two dipolarizations occur: First dipolarization is not strong and accompanies only weak(<150km/s) earthward/dawnward plasma flows, and in the second dipolarization that follows shortly, rather large amplitude magnetic fluctuations are seen, but it initiates with no significant earthward flow. The earthward bursty flow with a maximum speed of > 450km/s was observed, but delayed by ∼ 1 min with respect to the second dipolarization initiation. These features are in conflict with the flow-braking scenario for the substorm. Rather they fit better in the near-tail current disruption scenario.

  • PDF

Differential Effects of Ginsenoside Metabolites on HERG K+ Channel Currents

  • Choi, Sun-Hye;Shin, Tae-Joon;Hwang, Sung-Hee;Lee, Byung-Hwan;Kang, Ji-Yeon;Kim, Hyeon-Joong;Oh, Jae-Wook;Bae, Chun-Sik;Lee, Soo-Han;Nah, Seung-Yeol
    • Journal of Ginseng Research
    • /
    • v.35 no.2
    • /
    • pp.191-199
    • /
    • 2011
  • The human ether-a-go-go-related gene (HERG) cardiac $K^+$ channels are one of the representative pharmacological targets for development of drugs against cardiovascular diseases such as arrhythmia. Panax ginseng has been known to exhibit cardioprotective effects. In a previous report we demonstrated that ginsenoside $Rg_3$ regulates HERG $K^+$ channels by decelerating deactivation. However, little is known about how ginsenoside metabolites regulate HERG $K^+$ channel activity. In the present study, we examined the effects of ginsenoside metabolites such as compound K (CK), protopanaxadiol (PPD), and protopanaxatriol (PPT) on HERG $K^+$ channel activity by expressing human a subunits in Xenopus oocytes. CK induced a large persistent deactivatingtail current ($I_{deactivating-tail}$) and significantly decelerated deactivating current decay in a concentration-dependent manner. The $EC_{50}$ for persistent $I_{deactivating-tail}$ was $16.6{\pm}1.3$ ${\mu}M$. In contrast to CK, PPT accelerated deactivating-tail current deactivation. PPD itself had no effects on deactivating-tail currents, whereas PPD inhibited ginsenoside $Rg_3$-induced persistent $I_{deactivating-tail}$ and accelerated HERG $K^+$ channel deactivation in a concentration-dependent manner. These results indicate that ginsenoside metabolites exhibit differential regulation on Ideactivating-tail of HERG $K^+$ channel.

Psychological Effect of Personalized Services on Customer's Website Loyalty in Fashion -Focusing on Cognitive Efficiency, Website Socialness, and Perceived Enjoyment-

  • Lee, Eun-Jung
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.39 no.3
    • /
    • pp.394-407
    • /
    • 2015
  • Prior research highlighted personalized services as a crucial antecedent to website loyalty, yet little has been discussed on the underlying mechanism. The current study explores the intervening effects of the three psychological constructs in the personalization-loyalty relationship: cognitive efficiency, perceived enjoyment, and socialness. An experiment was conducted with a total of 414 U.S. shoppers on a fictitious e-tail site for jeans that employed different levels of personalized content. The results found that the participants exposed to the high-level personalization condition reported a higher cognitive efficiency and higher socialness perception regarding the fashion e-tail site; however, no direct effect of intensity of e-personalization was found on perceived enjoyment. Cognitive efficiency and enjoyment perceptions on the site significantly increased customers' loyalty intentions regarding the site, while website socialness perception had no direct effect on loyalty intentions. Website socialness showed indirect effects on website loyalty intentions only through cognitive efficiency and perceived enjoyment; however, no direct effect from website socialness was found. Implications and limitations of the study were discussed.

Prebreakdown Avalanche Pulses in Compressed SF6 under Uniform Field (평등전계에서 압축 SF6가스의 절연파괴 선구 애벌렌체의 전류 펄스)

    • The Transactions of the Korean Institute of Electrical Engineers
    • /
    • v.33 no.3
    • /
    • pp.106-111
    • /
    • 1984
  • Prebreakdown current pulses arising from avalanche growth in SF6 were recorded under static uniform field at pressures up to about 400kpa. At pressures less than 100kpa the current pulses consist of the electron component observed as the fast rise of current, the negative ioncomponent which is superimposed, and the positive ion component comprising the tail of the pulse. The values of positive ion drift velocity were measured from the present pulse data. At pressures in excess of about 100 Kpa the pulse shapes becam distorted such that quantitative analysis was no longer possible, and did not indicate the action of any photosecondary process at the cathode. Breakdown appers to result from the seperate development of single avalanche.

Case of Langerhans Cell Histiocytosis That Mimics Meningioma in CT and MRI

  • Zhu, Ming;Yu, Bing-Bing;Zhai, Ji-Liang;Sun, Gang
    • Journal of Korean Neurosurgical Society
    • /
    • v.59 no.2
    • /
    • pp.165-167
    • /
    • 2016
  • Langerhans cell histiocytosis (LCH) is a rare disorder histologically characterized by the proliferation of Langerhans cells. Here we present the case of a 13-year-old girl with LCH wherein CT and MRI results led us to an initially incorrect diagnosis of meningioma. The diagnosis was corrected to LCH based on pathology findings. An intracranial mass was found mainly in the dura mater, with thickening of the surrounding dura. It appeared to be growing downward from the calvaria, pressing on underlying brain tissue, and had infiltrated the inner skull, causing a bone defect. The lesion was calcified with the typical dural tail sign. The dural origin of the lesion was verified upon surgical dissection. There are no previous reports in the literature describing LCH of dural origin presenting in young patients with typical dural tail signs and meningioma-like imaging findings. The current case report underscores the need for thorough histological and immunocytochemical examinations in LCH differential diagnosis.

Taxonomic Review of a Rare Butterfly Ray Gymnura japonica (Gymnuridae, Chondrichthyes), in Korea (한국의 희귀 나비가오리[Gymnura japonica (나비가오리과, 연골어강)]의 분류학적 재검토)

  • Kim, Jin-Koo;Ryu, Jung-Hwa;Jang, Seo-Ha;Han, Kyeong-Ho;Kim, Byeong-Yeob
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.55 no.1
    • /
    • pp.30-36
    • /
    • 2022
  • We collected a total of four butterfly ray specimens (Gymnura japonica, 213.4-695.0 mm in total length) in Korea from 2016 to 2021 and investigated their morphological and molecular characteristics in order to clarify their taxonomic status. These features are summarized as follows. Disc lozenge-shaped, 1.8-2.0 times broader than long. Tail very short, post-cloaca length 23.9-28.2% in disc width. Snout short, no rostral cartilage. Clasper short, no hook. Dorsal surface uniform yellow or brownish grey, with or without rounded light yellow spots. An analysis of 434 base-pair sequences of mitochondrial DNA cytochrome c oxidase subunit I showed that all four specimens corresponded to G. japonica from Japan (Kimura-2-parameter distance = 0-0.2%), suggesting that the color patterns found may be due to intraspecific color variation. G. japonica resembles Gymnura poecilura but differs in that it has a shorter tail length to disc width (23.9-28.2% in G. japonica vs. 40.1-48.3% in G. poecilura). This study revealed that G. japonica occurred in areas affected by the Tsushima Warm Current, tentatively suggesting that G. japonica may be an indicator species for monitoring marine ecosystem changes due to climate change.

A Single-Center Experience of Robotic-Assisted Spine Surgery in Korea : Analysis of Screw Accuracy, Potential Risk Factor of Screw Malposition and Learning Curve

  • Bu Kwang Oh;Dong Wuk Son;Jun Seok Lee;Su Hun Lee;Young Ha Kim;Soon Ki Sung;Sang Weon Lee;Geun Sung Song;Seong Yi
    • Journal of Korean Neurosurgical Society
    • /
    • v.67 no.1
    • /
    • pp.60-72
    • /
    • 2024
  • Objective : Recently, robotic-assisted spine surgery (RASS) has been considered a minimally invasive and relatively accurate method. In total, 495 robotic-assisted pedicle screw fixation (RAPSF) procedures were attempted on 100 patients during a 14-month period. The current study aimed to analyze the accuracy, potential risk factors, and learning curve of RAPSF. Methods : This retrospective study evaluated the position of RAPSF using the Gertzbein and Robbins scale (GRS). The accuracy was analyzed using the ratio of the clinically acceptable group (GRS grades A and B), the dissatisfying group (GRS grades C, D, and E), and the Surgical Evaluation Assistant program. The RAPSF was divided into the no-breached group (GRS grade A) and breached group (GRS grades B, C, D, and E), and the potential risk factors of RAPSF were evaluated. The learning curve was analyzed by changes in robot-used time per screw and the occurrence tendency of breached and failed screws according to case accumulation. Results : The clinically acceptable group in RAPSF was 98.12%. In the analysis using the Surgical Evaluation Assistant program, the tip offset was 2.37±1.89 mm, the tail offset was 3.09±1.90 mm, and the angular offset was 3.72°±2.72°. In the analysis of potential risk factors, the difference in screw fixation level (p=0.009) and segmental distance between the tracker and the instrumented level (p=0.001) between the no-breached and breached group were statistically significant, but not for the other factors. The mean difference between the no-breach and breach groups was statistically significant in terms of pedicle width (p<0.001) and tail offset (p=0.042). In the learning curve analysis, the occurrence of breached and failed screws and the robot-used time per screw screws showed a significant decreasing trend. Conclusion : In the current study, RAPSF was highly accurate and the specific potential risk factors were not identified. However, pedicle width was presumed to be related to breached screw. Meanwhile, the robot-used time per screw and the incidence of breached and failed screws decreased with the learning curve.

Highly Efficient High-Voltage MOSFET Converter with Bidirectional Power Flow Legs

  • Ryu, Hyung-Min
    • Journal of Power Electronics
    • /
    • v.14 no.2
    • /
    • pp.265-270
    • /
    • 2014
  • In terms of power loss, a MOSFET has two advantages over an IGBT with an antiparallel diode: purely resistive without an offset voltage in conduction and no tail current at turn-off. However, the reverse recovery characteristic of the body diode is so poor that MOSFETs have not yet been available for high-voltage power converters with bidirectional power flow legs. This paper introduces how MOSFETs can be fully applied to high-voltage power converters with bidirectional power flow legs in order to achieve high efficiency. With a bidirectional DC-DC converter with one leg as the simplest example, the basic circuit topology and operating principle are described in detail. The high efficiency and stable operation of the proposed converter are validated through experiments with a 1.5 kW prototype.

Dissolved Oxygen Budget in Floating Net Cage of Fish Farm at the Coastal Area -In case of yellow tail farm in Konli-Do- (해산 어류 양식장 가두리의 DO수지 -곤리도 방어 양식장의 경우-)

  • KIM Yong Sool
    • Korean Journal of Fisheries and Aquatic Sciences
    • /
    • v.21 no.1
    • /
    • pp.30-34
    • /
    • 1988
  • In roastal fish farms the farmers, especialy engaging in dealing with the floating cage culture, going to know about relationships between holding capacity and water quality in cage. Some of water quality managers and specialists studing physiological ecology understand that the key of water quality management concerned fish farming is budget of dissolved oxygen. This paper deals with oxygen budget in floating cage of the yellow tail farms at southern coastal area in Korea. The sampling station is located at Konli-Do fish farm near Chungmu, and the data is collected for 24 hours from 3:00 p.m. 8th September 1987. In result, the needed oxygen coming after the consumption by the rearing fish had been supplied with the tide current exchange, the sum of oxygen produced by phytoplankton photosynthesis and diffused from atmosphere are no more that $43\%$ for the needs of sea water consumption included respiration of planktons and decomposition of organic matters. The optimum holding capacity of cage is possible to compute with the calculation of minimum diurnal water exchange rate $[Qin{\cdot}V^{-1}\;(C-\bar{c})]$ through net mesh of cage.

  • PDF