• Title/Summary/Keyword: asymmetrical structures

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Ban-mal and Hierarchical Structures : Professor Chung′s Theory Critically Examined (반말과 계층 구조 -정대현 교수의 반말 이론에 대한 비판적 검토-)

  • 선우환
    • Lingua Humanitatis
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    • v.5
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    • pp.93-106
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    • 2003
  • Professor Daihyun Chung has recently presented an intriguing view of Ban-mal(non-honorific expressions) in Korean. He criticizes uses of Ban-mal, on the grounds that they presuppose the existence of hierarchical structures in human beings. Professor Chung also advocates ″a relational theory of Ban-mal″ according to which ascriptions of 'n-mal' should be relativized to the speaker-hearer relationship. He employs this view in showing that uses of Ban-mal indeed presuppose the existence of hierarchical structures in human beings I claim that Professor Chung has not shown the credibility of his relational theory of Ban-mal, and that this very view leads to an unintended and undesirable consequence. Moreover, 1 show that even if we assume that this view is true for the sake of an argument, he is not able to show that uses of Ban-mal indeed presuppose the existence of hierarchical structures. All he can show is rather that uses of 'Ban-mal'(a meta-linguistic expression) presuppose the existence of hierarchical structures. Finally, 1 conclude that what really presupposes the existence of hierarchical structures is the asymmetrical uses of Ban-mal and honorific expressions.

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SSI effects on the redistribution of seismic forces in one-storey R/C buildings

  • Askouni, Paraskevi K.;Karabalis, Dimitris L.
    • Earthquakes and Structures
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    • v.20 no.3
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    • pp.261-278
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    • 2021
  • In the current work, a series of seismic analyses of one-storey asymmetrical reinforced concrete (R/C) framed buildings is accomplished while the effect of soil deformability on the structural response is investigated. A comparison is performed between the simplified elastic behavior of R/C elements according to the structural regulations' instructions to the possible non-linear behavior of R/C elements under actual circumstances. The target of the time history analyses is the elucidation of the Soil-Structure Interaction (SSI) effect in the seismic behavior of common R/C structures by examining the possible elastic or elastoplastic behavior of R/C sections because of the redistribution of the internal forces by employing a realistic damage index. The conclusions acquired from the presented elastic and elastoplastic analyses supply practical guidelines towards the safer design of structures.

Performance evaluation of a rocking steel column base equipped with asymmetrical resistance friction damper

  • Chung, Yu-Lin;Du, Li-Jyun;Pan, Huang-Hsing
    • Earthquakes and Structures
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    • v.17 no.1
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    • pp.49-61
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    • 2019
  • A novel asymmetrical resistance friction damper (ARFD) was proposed in this study to be applied on a rocking column base. The damper comprises multiple steel plates and was fastened using high-strength bolts. The sliding surfaces can be switched into one another and can cause strength to be higher in the loading direction than in the unloading direction. By combining the asymmetrical resistance with the restoring resistance that is generated due to an axial load on the column, the rocking column base can develop a self-centering behavior and achieve high connection strength. Cyclic tests on the ARFD proved that the damper performs a stable asymmetrical hysteretic loop. The desired hysteretic behavior was achieved by tuning the bolt pretension force and the diameter of the round bolt hole. In this study, full-scale, flexural tests were conducted to evaluate the performance of the column base and to verify the analytical model. The results indicated that the column base exhibits a stable self-centering behavior up to a drift angle of 4%. The decompression moment and maximum strength reached 42% and 88% of the full plastic moment of the section, respectively, under a column axial force ratio of approximately 0.2. The strengths and self-centering capacity can be obtained by determining the bolt pretension force. The analytical model results revealed good agreement with the experimental results.

Direct analysis of steel frames with asymmetrical semi-rigid joints

  • Chan, Jake L.Y.;Lo, S.H.
    • Steel and Composite Structures
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    • v.31 no.1
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    • pp.99-112
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    • 2019
  • Semi-rigid joints have been widely studied in literature in recent decades because they affect greatly the structural response of frames. In literature, the behavior of semi-rigid joints is commonly assumed to be identical under positive and negative moments which are obviously incorrect in many cases where joint details such as bolt arrangement or placement of haunch are vertically asymmetrical. This paper evaluates two common types of steel frames with asymmetrical beam-to-column joints by Direct Analysis allowing for plasticity. A refined design method of steel frames using a proposed simple forth order curved-quartic element with an integrated joint model allowing for asymmetrical geometric joint properties is presented. Furthermore, the ultimate behavior of six types of asymmetrical end-plate connections under positive and negative moment is examined by the Finite Element Method (FEM). The FEM results are further applied to the proposed design method with the curved-quartic element for Direct Analysis of two types of steel frames under dominant gravity or wind load. The ultimate frame behavior under the two different scenarios are examined with respect to their failure modes and considerably different structural performances of the frames were observed when compared with the identical frames designed with the traditional method where symmetrical joints characteristics were assumed. The finding of this research contributes to the design of steel frames as their asymmetrical beam-to-column joints lead to different frame behavior when under positive and negative moment and this aspect should be incorporated in the design and analysis of steel frames. This consideration of asymmetrical joint behavior is recommended to be highlighted in future design codes.

The Synaptic Organization of the Cat Striatum (고양이 선조체의 신경연접기구에 대한 형태학적 관찰)

  • Chung Jin-Woong;Choi Wol-Bong;Kwun Hung-Sik
    • Applied Microscopy
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    • v.8 no.1
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    • pp.53-66
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    • 1978
  • An attempt has been made to discriminate the synapses in the striatum consisting caudate nucleus, putamen and fundus striati of the cat with emphasis on the characteristic structures of axon terminals and postsynaptic profiles. The differentiation is based on the size and shape of vesicle in the bouton terminal, and the symmetrical or asymmetrical thickening the pre- and postsynaptic membrane. Four types of synapses could be differentiated: Type I: the bontons with asymmetrical,synaptic thickenings contain round 45 nm diameter vesicles and contact cell soma, dendritic shafts and dendritic spines (74%). Type II : the boutons contain round 45nm diameter vesicles and are associated with symmetrical membrane thickenings. These synapses are formed on the soma and dendritic shafts (6%). Type III: the boutons with symmetrical membrane thickenings contain 50-60 nm diameter pleomorphic vesicles, and contact soma and dendritic shafts (18%). Type IV: the terminals contain flattened vesicles ($25{\times}45 nm$) and are associated with symmetrical membrane thickenings. These synapses are found in contact with soma and dendritic shafts. Additionally, the bouton en passant, which is expanded from myelinated or unmyelinated axons containing round vesicles (45nm diameter) contacts the dendritic shaft or dendritic spine with asymmetrical membrane thickenings. Two unusual types of synapses, axo-axonic and dendro-dendritic, are found occasionally.

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A Study on Improvement of Linearity and Efficiency Compensation in a Power Amplifier Using Asymmetical Doherty Structure (비대칭 Doherty 구조를 이용한 전력 증폭기의 선형성 개선과 효율 보상에 관한 연구)

  • Kang, Dong-Jin;Han, Ki-Kwan;Lee, Ho-Woong
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.3 no.1
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    • pp.63-69
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    • 2010
  • In this paper, a new design method of asymmetrical configuration of main amplifier and peaking amplifier using changed bias point is proposed for excellent linearity, instead of the conventional Doherty structure. We have utilized the uneven wilkinson power divider for the unequal power drive at the input network of amplifiers. And we proposed a compensating method of the decreasing efficiency due to improving linearity using 3-stage Doherty structures. From the simulation results of asymmetrical Dohertry power amplifier and asymmetrical 3-stage Doherty power amplifier with uneven power drive are implemented. From the implementation and measurement results of the each amplifier, IMD characteristics have -55 dBc as the good efficiency of 13% compensates the decreased entire efficiency due to the improving linearity characteristics.

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Optimized Phase Noise of LC VCO Using an Asymmetrical Inductance Tank

  • Yoon Jae-Ho;Shrestha Bhanu;Koh Ah-Rah;Kennedy Gary P.;Kim Nam-Young
    • Journal of electromagnetic engineering and science
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    • v.6 no.1
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    • pp.30-35
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    • 2006
  • This paper describes fully integrated low phase noise MMIC voltage controlled oscillators(VCOs). The Asymmetrical Inductance Tank VCO(AIT-VCO), which optimize the shortcoming of the previous tank's inductance optimization approach, has lower phase noise performance due to achieving higher equivalent parallel resistance and Q value of the tank. This VCO features an output power signal in the range of - 11.53 dBm and a tuning range of 261 MHz or 15.2 % of its operating frequency. This VCO exhibits a phase noise of - 117.3 dBc/Hz at a frequency offset of 100 kHz from carrier. A phase noise reduction of 15 dB was achieved relative to only one spiral inductor. The AIT-VCO achieved low very low figure of merit of -184.6 dBc/Hz. The die area, including buffers and bond pads, is $0.9{\times}0.9mm^2$.

A study on transverse vibration characteristics of a sandwich plate with asymmetrical faces

  • Ahn, Namshik;Lee, Kangsu
    • Structural Engineering and Mechanics
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    • v.40 no.4
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    • pp.501-515
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    • 2011
  • Sandwich elements have high flexural rigidity and high strength per density. They also have excellent anti-vibration and anti-noise characteristics. Therefore, they are used for structures of airplanes and high speed ships that must be light, as well as strong. In this paper, the Reissner-Mindlin's plate theory is studied from a Hamilton's principle point of view. This theory is modified to include the influence of shear deformation and rotary inertia, and the equation of motion is derived using energy relationships. The theory is applied to a rectangular sandwich model which has isotropic, asymmetrical faces and an isotropic core. Investigations are conducted for five different plate thicknesses. These plates are identical to the sandwich plates currently used in various structural elements of surface effect ships (SES). The boundary conditions are set to simple supports and fixed supports. The elastic and shear moduli are obtained from the four-point bending tests on the sandwich beams.

A Study on the Design of High Efficiency Induction Motor by Grain-oriented Magnetic Cores (방향성 자기재료에 의한 유도전동기의 효율향상설계에 관한 연구)

  • 황영문;이인칠;안진우;박한웅
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.38 no.3
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    • pp.173-181
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    • 1989
  • A split-phase induction motor with asymmetrical magnetizing reactance axes develops starting torque and its efficiency can be high under certain conditions. In this paper, one method of producing the asymmetry of magnetizing reactance axes is described. The grain-oriented silicon steel core is used to produce the asymmetric axes instead of non-oriented silicon steel core which is used in general motors. The optimum design method for the motor is suggested and analyzed. To verify this suggestion, the permanent capacitor run type induction motors are designed to be driven at balanced condition by its asymmetrical effect, and then the oscillating torque due to the asymmetry of motor structures are analyzed. Tests of the sample motor have shown good performance comparable to ordinary types. This motor structure can be used where high effciency and reliability are required, and also the amount of core materials can be reduced due to its high permeability.

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Buckling Characteristics of Skin-Stringer Composite Stiffened Panel

  • Noh, Ji-Sub;Ghim, Yeong-Taek;Shin, Joon-Hyung;Kwon, Bo-Seong;Byun, Joon-Hyung;Nam, Young-Woo;Kweon, Jin-Hwe
    • Journal of Aerospace System Engineering
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    • v.14 no.6
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    • pp.68-73
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    • 2020
  • Skin-stringer structures are widely used in aircrafts due to their advantage of minimizing structural weight while maintaining load carrying capacity. However, buckling load can cause serious damage to these structures. Therefore, the buckling characteristics of skin-stringer structures should be carefully considered during the design phase to ensure structural soundness. In this study, finite element method was applied to predict the buckling characteristics of stiffened panels. In terms of the failure mode, finite element analysis showed a symmetrical buckling mode, whereas an asymmetrical mode was determined by experimentation. The numerical results were obtained and compared to the experimental data, showing a difference of 9.3% with regard to the buckling loads.