• Title/Summary/Keyword: C.V.A.

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Varistor Characteristics of ZPCCL-Based Ceramics Doped with $La_{2}o_{3}$ ($La_{2}o_{3}$가 첨가된 ZPCCL계 세라믹스의 바리스터 특성)

  • 정영철;류정선;남춘우
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.415-418
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    • 2001
  • The I-V characteristics and its stability of ZPCCL-based ceramic varistors doped with La$_2$O$_3$in the range of 0.0~4.0 mol% were investigated. The density of ceramics was increased in the range of 4.7~5.8 g/cm$^3$ with increasing La$_2$O$_3$content. As La$_2$O$_3$content is increased, the varistor voltage was decreased in the range of 503.49-9.42 V/mm up to 2.0 mol%, whereas increasing La$_2$O$_3$content further caused it to increase. The ZPCCL-based varistors were characterized by nonlinearity, in which the nonlinear exponent is in the range of 3.05~82.43 and leakage current is in the range of 0.24-100.22 $\mu$A. Among ZPCCL-based varistors, 0.5 mol% added-varistors exhibited an excellent nonlinearity, in which the nonlinear exponent is 82.43 and the leakage current is 0.24 $\mu$A. Furthermore, they exhibited a high stability, in which the variation rate of the varistor voltage and the nonlinear exponent was -1.11% and -6.72%, respectively, under DC stress, such as (0.80 V$_{1mA}$9$0^{\circ}C$/12h)+(0.85 V$_{1mA}$115$^{\circ}C$//12h) +(0.90 V$_{1mA}$12$0^{\circ}C$//12h)+(0.95 V$_{1mA}$1$25^{\circ}C$//12h)+(0.95 V$_{1mA}$15$0^{\circ}C$//12h). Consequently, it was estimated that ZPCCL-based ceramics will be applied to development of Pr$_{6}$O$_{11}$ based ZnO varistors having a high performance.e.rformance.e.

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Growth and characterization of CdTe single crystals by vertical Bridgman method (수직 Bridgman법에 의한 CdTe 단결정의 성장과 특성)

  • 정용길;신호덕;엄영호;박효열;진광수
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.6 no.2
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    • pp.220-228
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    • 1996
  • CdTe single crystals were grown by vertical Bridgman method using double furnace with two siliconit heating elements. When the peak temperature of the upper furnace was fixed at $1150^{\circ}C$ and that of the lower furnace was $800^{\circ}C$, the temperature gradient was about $22.5^{\circ}C$/cm. The lattice constant $a_0$ was $6.482\AA$ from the X-ray diffraction and the band gap energy obtained from the optical absorption experiment at room temperature was 1.478 eV. PL spectrum showed that the bound exciton emission peak was resolved into ($A^0,X$) (1.5902, 1.5887 eV), ($h\;D^0$) (1.5918 eV) and ($D^0,X$ (1.5928, 1.5932 eV), and we have also calculated binding energy and ionization energy of the neutral donor and acceptor.

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Ramsay-Hunt Syndrome involving the 2nd, 3rd cervical ganglia (경부 2, 3번 피부절을 침범한 Ramsay-Hunt 증후군 1례)

  • Lee, Chung Seok;Choi, Yong Seok;Song, Eun Hyang;Kim, Jeung Mee;Han, Jeong Ho;Kim, Doo Eung
    • Annals of Clinical Neurophysiology
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    • v.4 no.1
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    • pp.85-88
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    • 2002
  • Ramsay-Hunt syndrome is a viral disease associated with peripheral facial nerve paralysis accompany by erythematous vesicular rashs on the ear(zoster oticus) or in the mouth. Based on clinical presentations that indicated involvement of more than one ganglion, the gasserian, geniculate, petrous, accessory, jugular and second and third dorsal root ganglia comprised a chain in which inflammation of a single ganglion could extend to nearby ganglia. A 71-year-old man presented with left. peripheral facial palsy with otalgia, vesicular eruption in $V_2$, $V_3$, C2, C3 dermatome, tinnitus, and hearing loss.

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Effects of Ground Faults on the Safety of Persons and Low-voltage Installations in 22.9 kV-Y Distribution Systems (22.9 kV-Y 계통에서 지락고장이 인체 및 저압설비의 안전에 미치는 영향)

  • Kim, Han-Soo;Chung, Jae-Hee;Kang, Kae-Myung
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.1
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    • pp.141-148
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    • 2008
  • This paper presents experimental results on the safety of persons and protection of low-voltage equipments of the sub-station due to a single-phase ground fault in 22.9 kV-Y distribution system. In order to evaluate the hazard voltages and the stress voltage of the low-voltage(LV) equipment due to faults between high-voltage systems and earth based on the newly prescribed KS C IEC 60364 standard series, the verification tests in a 22.9[kV] neutral multiple grounding system were carried out. From the experimental results, we introduce serious problems causing some discomfort when applying KS C IEC 60364 standard series to the existing domestic distribution system and the effective protective measures against temporary overvoltages due to a ground fault in the common grounding which is combined the 22.9 kV-Y grounding and the customer's installation grounding are proposed. As a consequence, it was found that the equipotential bonding is an important prerequisite for the effectiveness of the protective measures for the safety of persons and LV equipment in the combined 22.9 kV-Y and low-voltage grounding system.

Isolation of the Protease-producing Yeast Pichia anomala CO-1 and Characterization of Its Extracellular Neutral Protease (세포 외 중성 단백질분해효소를 생산하는 Pichia anomala CO-1의 분리 동정 및 효소 특성)

  • Kim, Ji Yeon
    • Journal of Life Science
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    • v.29 no.10
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    • pp.1126-1135
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    • 2019
  • From a sample of bamboo byproduct, the protease-producing yeast strain CO-1 was newly isolated. Strain CO-1 is spherical to ovoid in shape and measures $3.1-4.0{\times}3.8-4.4{\mu}m$. For the growth of strain CO-1, the optimal temperature and initial pH were $30^{\circ}C$ and 4.0, respectively. The strain was able to grow in 0.0-15.0%(w/v) NaCl and 0.0-9.0%(v/v) ethanol. Based on a phylogenetic analysis of its 18S rDNA sequences, strain CO-1 was identified as Pichia anomala. The extracellular protease produced by P. anomala CO-1 was partially purified by ammonium sulfate precipitation, which resulted in a 14.6-fold purification and a yield of 7.2%. The molecular mass of the protease was recorded as approximately 30 kDa via zymogram. The protease activity reached its maximum when 1.0%(w/v) CMC was used as the carbon source, 1.0%(w/v) yeast extract was used as the nitrogen source, and 0.3%(w/v) $MnSO_4$ was used as the mineral source. The protease revealed the highest activity at pH 7.0 and $30^{\circ}C$. This enzyme maintained more than 75% of its stability at a pH range of 4.0-10.0. After heating at $65^{\circ}C$ for 1 hr, the neutral protease registered at 60% of its original activity. The protease production coincided with growth and attained a maximal level during the post-exponential phase.

Construction and Characterization of the Vibrio parahaemolyticus Collagenase Inactivated Mutant (Vibrio parahaemolyticus collagenase 불활성화 돌연변이체의 제조 및 특성)

  • 이재원;전인준;강호영;차재호
    • Journal of Life Science
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    • v.14 no.2
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    • pp.362-367
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    • 2004
  • For better understanding of the host infection mechanism of Vibrio, a Vibrio parahaemolyticus collagenase mutant was generated by insertional inactivation of a vppC gene encoding extracellular collagenase. A recombinant DNA containing vppC::nptII was cloned into a suicide plasmid pDMS197, resulted in pVCM03. The recombinant suicide plasmid pVCM03 contained in E. coli $\chi$7213 was transferred to a wild-type V. parahaemolyticus 04 through conjugation. The recombinant vppC::nptII DNA in pVCM03 was exchanged with wild-type allele by homologous recombination resulting vppC mutant, V. parahaemolyticus CM. The mutant was selected and screened on TCBS media containing 10% sucrose and kanamycin. The mutation by allele exchange was confirmed with the comparison of the size of DNAs amplified by PCR. V. parahaemolyticus CM showed at least 4-fold less collagen-degrading activity than those of wild-type, and the mutant exhibited less cytotoxicity than that of wild-type in MTT assay.

Patho-anatomy and treatment of complex congenital cardiovascular anomalies associated with left superior vena cava: report of 16 cases (좌상공정맥을 합병한 복합심혈관기형의 병리해부와 수술 성적: 16례 보)

  • 정원상
    • Journal of Chest Surgery
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    • v.17 no.2
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    • pp.177-183
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    • 1984
  • From July 1975 to March 1984, 16 patients of complex congenital cardiovascular anomalies associated with left superior vena cava were seen at Han-Yang University Hospital. The age of patients was ranged from 2 to 15 years-old. The distribution of Sex was 7 patients in male, 9 patients in female. Persistent Left Superior Vena Cava [L.S.V.C.] was classified according to the proximal connection of L.S.V.C. into 3 groups. Group I which L.S.V.C. connected to coronary venous sinus was in 9 patients, Group II which L.S.V.C. connected to Left atrium was in 5 patients, Group III which L.S.V.C. hemodynamically connected to right atrium was in 2 patients. Pathoanatomical findings of complex congenital cardiovascular anomalies associated with L.S.V.C. in 16 cases were generally show unsystematic irregularity. In group I, A.S.D. were only in 3 cases, but in highest incidence and in group III, all two cases were supracardiac type of total anomalous drainage of pulmonary veins. Post-operatively, 3 patients among 14 patients of total correction, were died immediately, 1 patient of palliative shunt operation was died after 2 and half years, and Follow-up results of other remaining patients were excellent.

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V2X Communication Module Design with Hybrid LTE-WAVE (LTE-WAVE 복합형 V2X 통신모듈 설계)

  • Lim, Ki-taeg;Jin, Seong-keun;Kwak, Jae-min
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2018.05a
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    • pp.395-398
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    • 2018
  • we propose a design method and process for hardware and software of hybrid V2X communication systems that support both C-ITS communication protocol and Legacy LTE communication technology. The hybrid V2X communication systems support multiple communication technologies of WAVE and LTE, in which WAVE supports multiple channels, so that it is designed to transmit road information such as LDM and positioning correction information to an autonomous vehicle in real time.

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Coefficient of Variability of Agronomic Characters in Panax ginseng C.A. Meyer (인삼 주요형질의 변이계수)

  • 안상득;최광태
    • Journal of Ginseng Research
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    • v.9 no.1
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    • pp.9-14
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    • 1985
  • The aerial parts, stem diameter, stem length, Petiole length, leaf length and leaf width were investigated to estimate coefficient of variability in ginseng at 2 to 4 years grown under the conventional and improved shadings. C.V values of characters such as stem length, petiole length, leaf length and leaf width were decreased with increasing the plant age, while that of steam diameter was increased. C.V. values of aerial part characters were higher in conventional shading than in improved shading, and the variance of c.v. was not significant when above 20 plants were investigated.

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V-I Properties of Silicone Gel (실리콘 젤의 전압-전류 특성)

  • 송병기;최성오;신종열;이태훈;홍진웅
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1997.11a
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    • pp.377-380
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    • 1997
  • In order to investigate the electrical characteristics due to the curing condition of silicone gel for Power Semiconductor, the V-I characteristics is studied. For experiment, We have made up several samples of different curing temperature and time such as 1[H],2[H] at 150[$^{\circ}C$], 160[$^{\circ}C$], 170[$^{\circ}C$]. As a result of the V-I characteristics, it is confirmed that the properties of specimen cured at 170[$^{\circ}C$], 2[H] is stable.

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