• Title, Summary, Keyword: stable range one

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ON LIFTING OF STABLE RANGE ONE ELEMENTS

  • Altun-Ozarslan, Meltem;Ozcan, Ayse Cigdem
    • Journal of the Korean Mathematical Society
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    • v.57 no.3
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    • pp.793-807
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    • 2020
  • Stable range of rings is a unifying concept for problems related to the substitution and cancellation of modules. The newly appeared element-wise setting for the simplest case of stable range one is tempting to study the lifting property modulo ideals. We study the lifting of elements having (idempotent) stable range one from a quotient of a ring R modulo a two-sided ideal I by providing several examples and investigating the relations with other lifting properties, including lifting idempotents, lifting units, and lifting of von Neumann regular elements. In the case where the ring R is a left or a right duo ring, we show that stable range one elements lift modulo every two-sided ideal if and only if R is a ring with stable range one. Under a mild assumption, we further prove that the lifting of elements having idempotent stable range one implies the lifting of von Neumann regular elements.

RINGS WITH MANY REGULAR ELEMENTS

  • Ashrafi, Nahid;Nasibi, Ebrahim
    • Communications of the Korean Mathematical Society
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    • v.32 no.2
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    • pp.267-276
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    • 2017
  • In this paper we introduce rings that satisfy regular 1-stable range. These rings are left-right symmetric and are generalizations of unit 1-stable range. We investigate characterizations of these kind of rings and show that these rings are closed under matrix rings and Morita Context rings.

WEAKLY STABLE CONDITIONS FOR EXCHANGE RINGS

  • Chen, Huanyin
    • Journal of the Korean Mathematical Society
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    • v.44 no.4
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    • pp.903-913
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    • 2007
  • A ring R has weakly stable range one provided that aR+bR=R implies that there exists a $y{\in}R$ such that $a+by{\in}R$ is right or left invertible. We prove, in this paper, that every regular element in an exchange ring having weakly stable range one is the sum of an idempotent and a weak unit. This generalize the corresponding result of one-sided unit-regular ring. Extensions of power comparability and power cancellation are also studied.

UNIT-REGULARITY AND STABLE RANGE ONE

  • Chen, Huanyin
    • Bulletin of the Korean Mathematical Society
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    • v.47 no.3
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    • pp.653-661
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    • 2010
  • Let R be a ring, and let $\Psi$(R) be the ideal generated by the set {x $\in$R | 1 + sxt $\in$ R is unit-regular for all s, t $\in$ R}. We show that $\Psi$(R) has "radical-like" property. It is proven that $\Psi$(R) has stable range one. Thus, diagonal reduction of matrices over such ideal is reduced.

Modeling and Experimental Response Characterization of the Chevron-type Bi-stable Micromachined Actuator (Chevron형 bi-stable MEMS 구동기의 모델링 및 실험적 응답특성 분석)

  • 황일한;심유석;이종현
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.2
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    • pp.203-209
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    • 2004
  • Compliant bi-stable mechanism allows two stable states within its operation range staying at one of the local minimum states of the potential energy. Energy storage characteristics of the bi-stable mechanism offer two distinct and repeatable stable states, which require no power input to maintain it at each stable state. This paper suggests an equivalent model of the chevron-type bi-stable microactuator using the equivalent spring stiffness in the rectilinear and the rotational directions. From this model the range of spring stiffness where the bi-stable mechanism can be operated is analyzed and compared with the results of the FEA (Finite Element Analysis) using ANSYS for the buckling analysis, both of which show a good agreement. Based on the analysis, a newly designed chevron-type bi-stable MEMS actuator using hinges is suggested for the latch-up operation. It is found that the experimental response characteristics of around 36V for the bi-stable actuation for the 60$mu extrm{m}$ stroke correspond very well to the results of the equivalent model analysis after the change in cross-sectional area by the fabrication process is taken into account. Together with the resonance frequency experiment where 1760Hz is measured, it is shown that the chevron-type bi-stable MEMS actuator using hinges is applicable to the optical switch as an actuator.

A Study on the Character of Observation Time in order to Draw the Features of Spatial Primacy Effect - Focus on the Public space - (공간의 초두효과 특성 도출을 위한 주시시간특성에 관한 연구 - 공공공간의 로비를 대상으로 -)

  • Kim, Jong-Ha
    • Korean Institute of Interior Design Journal
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    • v.21 no.6
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    • pp.137-146
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    • 2012
  • This study introduced the concept of Primacy Effect for the analysis of the observation characters by time so as to analyze the characters of information which the users observing the lobby in a public space get when they encounter the space. From the viewpoint that the first impression on any space can motivate the judgement of space and continuous activities, the time range with the observation characters which can be regarded as Primacy Effect was analyzed in the aspects of continuity and saccade. First, with the case of alignment by time on three times of continuous observation, the perception attributes of subjects were shown to be very different among one another depending on which time range was applied for alignment. Second, the subjects with low average value of continuous observation times were found to be relatively stable in "ii~iii time ranges" and the time range of "0~5.10 seconds" was known to be the time range of relatively stable analysis for the characters of subjects' primacy effect to be analyzed. Third, the change of the amount of acquired information could be examined concretely through the analysis of observation attributes by time range, and the time range of "iii time range" showed more stable changing characters than other time ranges. Fourth, in the "iii time range" set up as a proper time range for the analysis of primacy effect had higher average value of 3.9 times of observation frequency compared with 6 times of continuous observation. As a grand average, 6 times(19.3) of average observation value was between 3 times(21.3) and 9 times(16.9), which enabled to set up 6 times of continuous observation as the number of observation times for stable analysis of primacy effect.

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Implementation of permanent Magnetic Repulsion Type of Magnetic Levitation Table Using One Degree-of-freedom Active Control (1 자유도 능동제어에 의한 영구자석 반발형 자기부상 테이블의 구현)

  • Jo, Yeong-Geun;Choe, Gi-Bong;Tadahiko Shinshi;Akira Shimokohbe
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.7
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    • pp.125-132
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    • 2002
  • This paper shows an experimental magnetic levitation table using one degree-of-freedom active control. The magnetic levitation table using repulsions of permanent magnets was theoretically presented already. Thus the objective of this paper is to prove stable levitation with only one degree-of-freedom active control experimentally. For the design of the system, at first, permanent magnets are selected. Secondly, the spring constants of the virtual spring are obtained by simulation. Thirdly, the moving magnets are arranged using a stable layout relation. Fourthly, a linear voice coil motor is designed. Finally, the magnetic levitation system is manufactured. The phenomenon of stable levitation in the manufactured table is proven by means of dynamic time and frequency responses. The differences between the theoretical natural frequencies and experimental ones are analyzed. Also, stable range in the control direction is shown experimentally.

Changes of Lectin from Viscum coloratum by Fermentation with Lactobacillus plantarum : Effect of pH and Temperature, Suger Specificity and Lymphocyte Stimulting Activity (유산균 발효에 의한 겨우사리 중의 렉틴 성분의 변화 : pH, 온도의 영향, 당 특이성, 림프구 자극분열효과)

  • 박원봉;김희숙;나혜복;함승시
    • YAKHAK HOEJI
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    • v.39 no.1
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    • pp.24-30
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    • 1995
  • Lectin from mistletoe(Viscum coloratum) fermented by Lactobacillus plantarum was compared with the lectin from unfermented mistletoe. Agglunating activity of fermented mistletoe was stable at pH 3.77~8.71, at temperature range of $0~40^{\circ}C$ and in the presence of 9 mental ions, which results are similar to unfermented one, but less stable at pH 2.03~3.00 and more stable at temperature $60~80^{\circ}C$ than lectin from unfermented one. Agglunating activity of lectin from mistletoe fermented for 1 or 2 days and from fraction number 42~54 was not inhibited by all sugars used except for lectin from fraction number 21~34. Mitogenic activity to murine lymphpocytes of lectin from mistletoe was decreased by fermentation process.

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Improvement in the Stability of Glycinecin A through Protein Fusion of the Two Structural Components

  • Kim, Youngmee;Somi K. Cho;Moonjae Cho
    • Journal of Microbiology
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    • v.39 no.3
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    • pp.177-180
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    • 2001
  • Glycinecin A, a bacteriocin produced by Xanthomonas campestris pv. glycines, inhibits the growth of X. c. pv. vesicatoria. We have reported that purified glycinecin A is composed of two polypeptides, is active over a wide range of pH (6 to 9), and is stable at temperatures up to 60$\^{C}$. Glycinecin A is a heterodimer consisting of 39- and 14-kDa subunits; the two encoding genes, glyA and glyB, respectively, have been cloned (Heu et al. 2001. Appl. Environ. Microbiol. 67, 4105-4110). Co-expression of glyA and glyB in the same cell is essential for bacteriocin activity. We constructed and produced a chimeric glycinecin A connecting glyA and glyB in one open reading frame. The chimeric glycinecin A has the same bactericidal activity as the wild-type glycinecin A. However, the chimeric glycinecin A is more stable in a wider range of pH and temperature.

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Analysis of Self-Pulsation Characteristics in Multi-Section Complex-Coupled DFB Lasers With Amplifying Optical Feedback (증폭된 광 귀환을 가자는 다중 전극 복소 결합 DFB 레이저에서 발생되는 self-pulsation 특성 해석)

  • Kim, Sang-Taek;Kim, Tae-Young;Kim, Boo-Gyoun;Leem, Young-Ahn;Park, Kyung-Hyun
    • Korean Journal of Optics and Photonics
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    • v.16 no.6
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    • pp.527-534
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    • 2005
  • We investigate the pulsation characteristics in a multi-section DFB laser which is composed of one DFB section, phase tuning section, and gain section. Multi-section DFB lasers with anti-phase (AP) complex-coupled (CC) DFB structure show wide current ranges of gain and phase tuning sections fer stable pulsations compared to those with in-phase CC DFB structure or index-coupled DFB structure. For multi-section DFB lasers with AP CC DFB structure, the current range of a gain section for stable pulsations increases and the tuning range of the pulsation frequency increases as a coupling strength or a gain coupling coefficient increases Also, the tuning range using the phase variation in a phase tuning section increases. For a fixed coupling strength, the current ranges of gain and phase tuning sections for stable pulsations increase and the tuning range of the pulsation frequency increases as the length of a DFB section increases.