• Journal of Welding and Joining
• /
• 제21권4호
• /
• pp.56-62
• /
• 2003

MIG brazing is used for many parts without melting base metal because of high productivity. Pulsed MIG brazing can be used to further reduce heat input and to improve the process stability. However, a significant amount of zinc in galvanized sheet steel is burned off in the area of brazes. Therefore, the brazing method to reduce the heat input is needed. In the brazing for galvanized sheet steel, variable polarity AC pulse MIG arc brazing can be applied to more decrease the heat input by setting EN-ratio adequately. In this research, we studied for the variable polarity AC pulse MIG arc brazing to decrease the heat input by using ERCuSi-A wire. As the result of increasing EN-ratio, melting ratio of base metal and burning off of zinc were reduced in galvanized sheet steel.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 1992년도 추계학술발표회논문집
• /
• pp.37-40
• /
• 1992

This paper examined the existance behavior of charged particles by measuring polarity inversion current Thermal Stimulate Current (TSC) and analysed appearance mechanism of polarity inversion current Peak and Also investigated relation between ionic space charge format ion and dielectric breakdown by measuring D.C breakdown impulse breakdown D.C - impulse superposition as a sample of FET. As a result. lie found that dielectric breakdown is likely to happen due to ionic space charge at the transient state when applied polarity inversion voltage and that charged partion of TSE Peak at the high temperature was the same as that of polarity inversion current. Also there was no effect on ionic space charge about the dielectric breakdown in stationary state when applied D.C voltage.

• 한국초전도ㆍ저온공학회논문지
• /
• 제19권2호
• /
• pp.44-47
• /
• 2017

In this paper, the current limiting characteristics of the transformer type superconducting fault current limiter (SFCL) with the two coupled secondary windings due to its winding direction were analyzed. To analyze the dependence of transient fault current limiting characteristics on the winding direction of the additional secondary winding, the fault current limiting tests of the SFCL with an additional secondary winding, wound as subtractive polarity winding and additive polarity winding, were carried out. The time interval of quench occurrence between two superconducting elements comprising the transformer type SFCL with the additional secondary winding was confirmed to be affected by the winding direction of the additional secondary winding. In case of the subtractive polarity winding of the additional secondary winding, the time interval of the quench occurrence in two superconducting elements was shorter than the case of the additive polarity winding.

• 전기전자학회논문지
• /
• 제3권2호
• /
• pp.285-294
• /
• 1999

본 논문에서는 다치논리 함수의 GRM(Generalized Reed-Huller)계수 생성 방법에 관하여 제안하였다 일반적인 GRM계수의 생성 방법은 Reed-Muller(RM) 전개식를 이용하여 극수 P=0의 RM계수를 구하고 이를 확장하여 모든 GRM계수를 구하는 방법을 사용한다. 본 논문에서 제안한 알고리즘은 모든 극수의 GRM계수를 구하지 않고 극수의 0의 개수를 순차적으로 비교해가며 GRM계수를 구하는 방식이다.

• 한국군사과학기술학회지
• /
• 제11권3호
• /
• pp.154-160
• /
• 2008

We investigated molecular polarity by using theoretical means and comparing empirical solvent polarity. Our approach employed electrostatic potentials at the molecular surface calculated by density functional methods. A number of molecular descriptors related to molecular polarities were computed from molecular surface electrostatic potentials. Among computed molecular descriptors, the most positive electrostatic potential provided the best correlation with the empirical solvent polarities. A regression equation was developed in order to predict molecular polarities of molecules whose experimental solvent polarities were unknown. The new regression equations were utilized in estimating solvent polarities of cubane derivatives which are considered important precusors of high-energy density meterials.

• 대한화학회지
• /
• 제11권4호
• /
• pp.126-131
• /
• 1967

各 種 아민(triethylamine, diethylamine, pyridine, diphenylamine, dimethylaniline)과 各種 Electron Acceptor($CCl_4,\;ICl,\;I_2$)를 Hexane 溶媒 存在下에서 作用시킨 結果 各各 Charge Transfer Complex를 形成하였으나 그 形成能은 아민의 Basicity에 比例하였고 Electron Donor의 Polarity의 差가 클 때에는 다른 形式의 Complex를 形成함을 紫外線 吸收 分光法으로 確認하였다. Complex 形成能과 아민의 Basicity 및 Electron Acceptor의 Polarity의 關係를 論하였다.

• 한국재료학회지
• /
• 제25권7호
• /
• pp.352-357
• /
• 2015

To research the characteristics of ITO film depending on a polarity of SiOC, specimens of ITO/SiOC/glass with metal-insulator-substrates (MIS) were prepared using a sputtering system. SiOC film with 17 sccm of oxygen flow rate became a non-polarity with low surface energy. The PL spectra of the ITO films deposited with various argon flow rates on SiOC film as non-polarity were found to lead to similar formations. However, the PL spectra of ITO deposited with various argon flow rates on SiOC with polarity were seen to have various features owing to the chemical reaction between ITO and the polar sites of SiOC. Most ITO/SiOC films non-linearly showed the Schottky contacts and current increased. But the ITO/SiOC film with a low current demonstrated an Ohmic contact.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 제38회 하계학술대회
• /
• pp.1436-1437
• /
• 2007

This paper presents the experimental results of the dielectric characteristics with temperature changes under highly non-uniform electric field in $SF_6$ gas. The impulse preliminary breakdown developments were investigated by the measurement of predischarge current and breakdown voltage. As a result, the first stremer corona is initiated at the tip of needle electrode, and bridges the test gap. Also the first stremer corona onset and breakdown voltages the negative polarity was much higher than that in the positive polarity in same temperature. In addition, the varition of temperature have a little effect on the positive polarity. On the other hand, in some cases negative polarity corona onset and breakdown voltages increased with increasing a high temperature.

• 한국언어정보학회지:언어와정보
• /
• 제8권1호
• /
• pp.53-76
• /
• 2004

Negative polarity items(NPIs), which function as quantifiers are licensed in a syntactically strict way by negatives, which function as qualifiers, resulting in universal negating interpretations as pairs. We present a proposal to explain the related phenomena, in which the syntax and the semantics are closely related to each other, with Combinatory Categorial Grammar. For this purpose, we first adopt the usual approach to scrambling, but control its overgeneration with the use of markers, taking into account the complex syntactic phenomena involving NPIs and scrambling in Korean. We also propose to utilize polarity intensity as a novel feature, in order to account for the universal negating interpretations when NPIs are combined with negatives. Our proposal also explains the difference in readings when other quantifiers or qualifiers intervene the NPI and the related negatives.

• 천문학회지
• /
• 제52권4호
• /
• pp.89-97
• /
• 2019

We demonstrate the subsurface origin of the observed evolution of the solar active region 10930 (AR10930) associated with merging and breakup of magnetic polarity regions at the solar surface. We performed a magnetohydrodynamic simulation of an emerging magnetic flux tube whose field-line twist is asymmetrically distributed along its axis, which is a key to merging and fragmentation in this active region. While emerging into the surface, the flux tube is subjected to partial splitting of its weakly twisted portion, forming separate polarity regions at the solar surface. As emergence proceeds, these separate polarity regions start to merge and then break up, while in the corona sigmoidal structures form and a solar eruption occurs. We discuss what physical processes could be involved in the characteristic evolution of an active region magnetic field that leads to the formation of a sunspot surrounded by satellite polarity regions.