• 제목/요약/키워드: levels of analysis and structure

Search Result 765, Processing Time 0.03 seconds

Study of the Resonance Structures of the Preionizing Spectrum of Molecular Hydrogen by Phase-shifted Multichannel Quantum Defect Theory

  • Lee, Chun-Woo
    • Bulletin of the Korean Chemical Society
    • /
    • v.33 no.3
    • /
    • pp.809-817
    • /
    • 2012
  • The resonance structure of the preionization spectrum of $H_2$ in the region immediately above its ionization threshold, ($^2{\sum}_{g}^{+}$, $\nu^+=0$, $N^+=0$) converging toward its rotationally excited ($\nu^+=0$, $N^+=2$) limit, is complicated due to perturbation by the vibrationally excited levels $7_{p\pi}\;v=1$ and $57_{p\pi}\;v=2$. The spectra of interlopers are separated from the rotationally preionizing Rydberg series to allow analysis of this complex resonance structure. Although only two vibrationally excited levels perturb the rotational preionization spectrum, at least 6 interloper Rydberg series participate in the complex spectrum over most of its energy range and more interloper series participate at a narrow range around $124500cm^{-1}$ in the spectrum. To allow handling of an arbitrary number of interloper series, MATLAB$^{(R)}$'s symbolic operation is used to perform on-the-fly formulation.

A Study of Husband's Stress, Communication, Family Cohesion and Adaptation in Families Living Apart and Living Together (가구주분리가족과 일반가족의 가구주스트레스, 의사소통, 가족응집성.적응성의 비교연구)

  • Hong, Sang-Ook;Bae, Ok-Hyun
    • Korean Journal of Human Ecology
    • /
    • v.7 no.1
    • /
    • pp.11-24
    • /
    • 1998
  • This study aims to compare the husband's stress, communication, family cohesion and adaptation which contribute to the internal structure of conjugal understanding between families living apart from one another and those living together. The data for analysis was derived from questionnaires. 172 husbands from families living apart and 185 husbands who live with their families. The data was treated by spss pc+ program and the methods of analysis were frequency, t-test and one-way ANOVA. The results of this study were as follows : 1. Husband's stress in conjugal understanding in families living apart was higher than those who live with their families. 2. Between the husbands whose families are living apart and those who are living together, there were no significant differences in effort levels to overcome stress, family cohesion, family adaptation and communication needs for conjugal understanding. 3. Husbands who live with their families communicate differently according to the degree of their stress levels. 4. Low stress levels led to high family cohesion and family adaptation in both cases. 5. High communication levels led to high family cohesion and family adaptation in both cases.

  • PDF

Behavior of symmetrically haunched non-prismatic members subjected to temperature changes

  • Yuksel, S. Bahadir
    • Structural Engineering and Mechanics
    • /
    • v.31 no.3
    • /
    • pp.297-314
    • /
    • 2009
  • When the temperature of a structure varies, there is a tendency to produce changes in the shape of the structure. The resulting actions may be of considerable importance in the analysis of the structures having non-prismatic members. Therefore, this study aimed to investigate the modeling, analysis and behavior of the non-prismatic members subjected to temperature changes with the aid of finite element modeling. The fixed-end moments and fixed-end forces of such members due to temperature changes were computed through a comprehensive parametric study. It was demonstrated that the conventional methods using frame elements can lead to significant errors, and the deviations can reach to unacceptable levels for these types of structures. The design formulas and the dimensionless design coefficients were proposed based on a comprehensive parametric study using two-dimensional plane-stress finite element models. The fixed-end actions of the non-prismatic members having parabolic and straight haunches due to temperature changes can be determined using the proposed approach without necessitating a detailed finite element model solution. Additionally, the robust results of the finite element analyses allowed examining the sources and magnitudes of the errors in the conventional analysis.

A Full-Wave Model Analysis on Noise Reduction and Impedance of Power-Bus Cavity with Differential Signaling

  • Kahng, Sung-Tek
    • Journal of electromagnetic engineering and science
    • /
    • v.6 no.4
    • /
    • pp.197-202
    • /
    • 2006
  • This paper presents a study on the differential signaling for the rectangular power-bus structure. The full-wave modal analysis method analyzes how the differential-signaling can lower the power-bus resonance noise levels. The methodology is validated by the use of the FDTD method and reference measurements.

Shaking Table Test and Seismic Performance Evaluation of Shanghai Tower

  • Chunyu, Tian;Congzhen, Xiao;Hong, Zhang;Jinzhe, Cao
    • International Journal of High-Rise Buildings
    • /
    • v.1 no.3
    • /
    • pp.221-228
    • /
    • 2012
  • Shanghai Tower is a super high-rise building of 632 m height with 'mega frame-core- outrigger truss' structure system. Due to the complexity and irregularity of structure, shaking table test was carried out to investigate its seismic performance. A 1/40 scaled test model was designed, built and tested on shaking table under earthquake of small, moderate and large levels. The experimental results showed that the structure can meet the requirements of Chinese codes and reach scheduled performance objectives. Elastic and plastic time-history analysis on the structure were carried out and the results were compared to experimental results. Based on the research results some suggestions were proposed to contribute favorable effect on the seismic capacity of the structure.

An Analysis of the Effects of Learning Stress for Inquiry Activities in College Earth Science Course

  • Cho, Jae-Hee;Kim, Hak-Sung;Shin, Hyun-Chul
    • Journal of the Korean earth science society
    • /
    • v.39 no.4
    • /
    • pp.349-360
    • /
    • 2018
  • This study analyzed variations of learning stress by comparing the salivary cortisol levels of students who participated in Earth Science inquiry activities. The cortisol concentrations between the pre- and post-inquiries of the sample of 34 university students, who had taken the course of 'Basic Earth Science and Experiments', were analyzed. The Earth Science inquiries consisted of geology and astronomy activities. The observational geology activities consisted of a session of 'structure contours and map patterns' and the cognitive astronomy activities consisted of a session of 'representations of horizontal and equatorial coordinates'. These Earth Science inquiry activities were found to cause students to have anxiety, and the thought processes that these activities involved were found to cause learning stress. The variations in cortisol concentrations of students increased by $1.6{\pm}5.9ng\;mL^{-1}$ after conducting observational activities in geology compared with $2.1{\pm}6.2ng\;mL^{-1}$ after doing cognitive activities in astronomy. The analysis of the observational activities in the geology inquiry activities indicated that they were consistent with low levels of learning stress. Conversely, the analysis of the cognitive activities in the astronomy inquiry activities showed significant individual variations in cortisol concentrations. Furthermore, individual differences in cognitive ability were reflected in the astronomy inquiry activities. While students, who received high scores, exhibited low levels of stress in the geology inquiry activities, they showed high levels of stress in the astronomy inquiry activities. It was concluded that, in the case of students with high scores in the study, the level of learning stress increased due to the raised anxiety in cognitive inquiry activities. In contrast, students, who received low scores in the study, exhibited high levels of stress in the geology inquiry activities, and low levels of stress in the astronomy inquiry activities.

Structural System Reliability Analysis of Semi-rigid Connected Frame - Focused on Plastic Greenhouse - (반강결 프레임 구조물의 시스템 신뢰성 해석 - 비닐하우스를 중심으로 -)

  • Lee, Sangik;Lee, Jonghyuk;Jeong, Youngjoon;Kim, Dongsu;Seo, Byunghun;Seo, Yejin;Choi, Won
    • Journal of The Korean Society of Agricultural Engineers
    • /
    • v.64 no.5
    • /
    • pp.67-77
    • /
    • 2022
  • Recently, the trend in structural analysis and design is moving towards the development of reliable system. The reliability-based method defines various limit states related to usability and failure, thereby enabling multiple levels of design according to the importance of a structure. Meanwhile, an actual structure is composed of a set of several elements, and particularly, a frame type is composed of a system in which the members are connected each other. At this time, the actual connection between members is in a semi-rigid condition, not in complete rigid or hinged. This semi-rigid is found in several structures, especially in agricultural facilities designed with lightweight materials. In this study, a system reliability analysis technique for frame structure was established, and applied to an analysis of the semi-rigid connection. Various conditions of correlation were applied to reflect the connectivity between members, and through this, the limitations of existing structural analysis method and the behavioral characteristics of structure were analyzed. The failure probability of the frame member component and the overall structure system was significantly different in consideration of the semi-rigid connection. In addition, it was evaluated that the behavior of structure can be more accurately analyzed if the correlation according to the position of members in a system is further investigated.

A nonlinear structural experiment platform with adjustable plastic hinges: analysis and vibration control

  • Li, Luyu;Song, Gangbing;Ou, Jinping
    • Smart Structures and Systems
    • /
    • v.11 no.3
    • /
    • pp.315-329
    • /
    • 2013
  • The construction of an experimental nonlinear structural model with little cost and unlimited repeatability for vibration control study represents a challenging task, especially for material nonlinearity. This paper reports the design, analysis and vibration control of a nonlinear structural experiment platform with adjustable hinges. In our approach, magnetorheological rotary brakes are substituted for the joints of a frame structure to simulate the nonlinear material behaviors of plastic hinges. For vibration control, a separate magnetorheological damper was employed to provide semi-active damping force to the nonlinear structure. A dynamic neural network was designed as a state observer to enable the feedback based semi-active vibration control. Based on the dynamic neural network observer, an adaptive fuzzy sliding mode based output control was developed for the magnetorheological damper to suppress the vibrations of the structure. The performance of the intelligent control algorithm was studied by subjecting the structure to shake table experiments. Experimental results show that the magnetorheological rotary brake can simulate the nonlinearity of the structural model with good repeatability. Moreover, different nonlinear behaviors can be achieved by controlling the input voltage of magnetorheological rotary damper. Different levels of nonlinearity in the vibration response of the structure can be achieved with the above adaptive fuzzy sliding mode control algorithm using a dynamic neural network observer.

Interior Noise Reduction of a Passenger Car using Panel Contribution Analysis (패널 기여도 분석에 의한 승용차의 실내 소음 저감)

  • 이두호;김태정
    • Journal of KSNVE
    • /
    • v.9 no.4
    • /
    • pp.785-794
    • /
    • 1999
  • The panel contribution analysis to reduce interior booming noise of a passenger car is carried out using both experimental method and numerical one. The accelerations of panels are measured on the outer surface of car body during operation. The acoustic characteristic of cavity is represented by two different ways. One is the acoustic transfer function obtained by experiment with reciprocal manner. The other is the boundary element model and numerical results of the model are calculated using SYSNOISE. The results from numerical method show more good agreement with measured sound pressure levels than the experimental one. Contributions of panels for interior noise are ranked and structure of the car is reinforced according to the results, which shows that the panel contribution analysis is a powerful tool to lessen structure-borne noise of passenger vehicle.

  • PDF

Early Vocalization and Phonological Developments of Typically Developing Children: A longitudinal study (일반 영유아의 초기 발성과 음운 발달에 관한 종단 연구)

  • Ha, Seunghee;Park, Bora
    • Phonetics and Speech Sciences
    • /
    • v.7 no.2
    • /
    • pp.63-73
    • /
    • 2015
  • This study investigated longitudinally early vocalization and phonological developments of typically developing children. Ten typically developing children participated in the study from 9 months to 18 months of age. Spontaneous utterance samples were collected at 9, 12, 15, 18 months of age and phonetically transcribed and analyzed. Utterance samples were classified into 5 levels using Stark Assessment of Early Vocal Development-Revised(SAEVD-R). The data analysis focused on 4 and 5 levels of vocalizations classified by SAEVD-R and word productions. The percentage of each vocalization level, vocalization length, syllable structures, and consonant inventory were obtained. The results showed that the percentages of level 4 and 5 vocalizations and word significantly increased with age and the production of syllable structures containing consonants significantly increased around 12 and 15 months of age. On average, the children produced 4 types of syllable structure and 5.4 consonants at 9 months and they produced 5 types of syllable structure and 9.8 consonants at 18 months. The phonological development patterns in this study were consistent with those analyzed from children's meaningful utterances in previous studies. The results support the perspective on the continuity between babbling and early speech. This study has clinical implications in early identification and speech-language intervention for young children with speech delays or at risk.