• Title/Summary/Keyword: Frequency response character

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A Study on Sound Radition from the Periodic Structure depend on Symmetrical beam space Using FEM (FEM을 이용한 대칭형 보강재에 보강된 평판의 음향방사에 관한 연구)

  • Kim J.T.;Kim T.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.732-739
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    • 2005
  • The determination of sound pressure radiated from periodic plate structures is fundamental in the estimation of noise level in aircraft fuselages or ship hull structures. As a robust approach to this problem, here a very general and comprehensive analytical model is developed for predicting the sound radiated by a vibrating plate stiffened by periodically spaced orthogonal symmetrical beams subjected to a sinusoidally time varying point load. In this these, we experiment with the numerical analysis using the space harmonic series and the SYSNOISE for measuring the vibration mode and character of response caused by sound radiation with adding the harmonic point force in the thin isotropic plate supported by the rectangular lattice reinforcement. We used the reinforcements, beams of open type section like the style of 'ㄷ' letter; the space of the beams were chosen to be 0.2m, 0.3m, 0.4m. We studied the behavior of sound pressure levels, analysis of vibration mode between support points, connection between frequency function and sound pressure levels, and connection between position function and sound pressure levels.

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Propagation characteristics of blast-induced vibration to fractured zone (파쇄영역에 따른 발파진동 전파특성)

  • Ahn, Jae-Kwang;Park, Duhee;Park, Ki-Chun;Yoon, Ji Nam
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.6
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    • pp.959-972
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    • 2017
  • In evaluation of blast-induced vibration, peak particle velocity (PPV) is generally calculated by using attenuation relation curve. Calculated velocity is compared with the value in legal requirements or the standards to determine the stability. Attenuation relation curve varies depending on frequency of test blasting, geological structure of the site and blasting condition, so it is difficult to predict accurately using such an equation. Since PPV is response value from the ground, direct evaluation of the structure is impractical. Because of such a limit, engineers tend to use the commercial numerical analysis program in evaluating the stability of the structure more accurately. However, when simulate the explosion process using existing numerical analysis program, it's never easy to accurately simulate the complex conditions (fracture, crushing, cracks and plastic deformation) around blasting hole. For simulating such a process, the range for modelling will be limited due to the maximum node count and it requires extended calculation time as well. Thus, this study is intended to simulate the elastic energy after fractured zone only, instead of simulating the complex conditions of the rock that results from the blast, and the analysis of response characteristics of the velocity depending on shape and size of the fractured zone was conducted. As a result, difference in velocity and attenuation character were calculated depending on fractured zone around the blast source appeared. Propagation of vibration tended to spread spherically as it is distanced farther from the blast source.

호스피스 자원봉사자의 활동과 영적안녕에 관한 연구

  • Cha, Yeong-Nam;Han, Hye-Sil;Jeong, Jeong-Suk;Yun, Mae-Ok;Choe, Eun-Ju
    • Korean Journal of Hospice Care
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    • v.2 no.1
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    • pp.41-57
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    • 2002
  • This study was done to examine spiritual well-being of hospice care service volunteers for the purpose of providing them with programs promoting coping skills in response to the wholistic needs of patient effectively, also providing data for professional or nonprofessional hospice training program. Subjects were 123 volunteers serving in 6 hospice centers in Jeonbuk province at present. Data collection were done from 16 Oct. 2000 to 17 Nov. 2000. questionnairs were consisted of activities of hospice care service volunteer and spiritual well-being. The study results were as follows 1.Mean of activities of hospice care service volunteers were 2.433, those activities were divided into 5 categories such as spiritual, activities of volunteer for themselves, psychosocial, physical area and bereavement. The highest mean score was spiritual area 2.578, activities of volunteers for themselves 2.525, psychosocial area 2.456, physical area was 2.359 and the lowest mean score was bereavement area 2.130. 2.Spiritual well-being of hospice care service volunteers was 5.25, the highest mean. In subcategories of spiritual well-being, religious spiritual well-being was higher than existential spiritual well-being, mean score for each one was 5.41, 5.10. 3.Statistically significant relations among demographic characteristics such as gender(t=2.72, P=.008), status of marriage(t=6.067, P=.003), occupation(F=3.795, P=.025), frequency of visiting for volunteered hospice care(F=3.833, P=.024) were noted. 4.Statistically significant demographic characteristics of hospice service volunteers was religion(t=-4.38, p=0.000), status of marriage(F=3.505, p=0.033), frequency of visiting for volunteered hospice care(F=3.107, p=0.048), level of satisfaction from hospice care volunteer service(F=3.610, p=0.030), hospice service volunteers doing more home visiting(5-9times/month) had higher status of spiritual well being than volunteer with less home visiting(1-4times/month) 5.A significant relationship between activities of hospice service volunteers and status of spiritual well-being was noted(r=.236, p=.004), activities of hospice service volunteers was related to both subcategories of spiritual well-being such as religious well-being(r=.210, p=.010) and existential well-being(r=.208, p=.011). From the results of the study It is noted that status of spiritual well-being for hospice volunteers influences on service activities. It means spiritual well-being should be considered as a essential character for hospice service volunteers, it also means that managing and maintaining of status of spiritual well-being for hospice service volunteers is important. On the base of the study recommendation are made as follows: 1.Considering status of spiritual well-being for hospice care service volunteers is needed to promote hospice care activities. 2.It is necessary to develope spiritual well-being programs for hospice care service volunteers and further study for effect validation of them is needed. 3.Further study to sort out effecting variables for hospice care service volunteer activities is needed. 4.It will be desirable to have spiritual well-being information included in the hospice education program.

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Studies on the Breeding of the Response to short photoperiod, Fiber weight, and Qualitative characters and of the Associations Among these characters in Kenaf (섬유용양마의 육종에 관한 연구 -단일반응성과 섬유종의 유전 및 연소)

  • Johng-Moon Park
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.4 no.1
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    • pp.115-124
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    • 1968
  • It was shown that the most desirable characters for kenaf are high-fiber weight and moderately early maturity. Therefore, the objectives of this research on this crop is to find varieties possessing these characteristics. The experiments covered in this report provided new information relative to segregation, mode of inheritance, estimate of the number of genes involved in fiber weight and their response to short day length of 10 hours and the qualitative characters, such as, color of stem, capsule, petiole and shape of leaves. The associations which exist among these characters are also indicated. Fiber weight per plant, days to flowering, Stem color, Petiole color, Capsule color, and shape of leaves were studied in parental, $F_1$.$F_2$and backcross populations of a cross between Dashkent, a low-fiber weight but early maturing kenaf variety, and G 38 F-1, a high-fiber weight but late maturing kenaf variety. Crosses were made using the varieties, Dashkent and G 38 F-1 as parents. The Dashkent parent had the following characteristics: green stems, capsules and petioles and lobed shaped leaves; 105.8234 mean-days to flowering in the field, and 106.9222 mean-days under 10 hours short day treatment. The other parent, G 38 F-1 had red stems yellow capsules and red petioles and unlobed shaped leaves; 149.8921 mean-days to flowering in the field, and 62.3684 mean-days under 10 hours short day treatment. Both of the parents, $F_1$, $F_2$, $BC_1$ ($F_1$ X Dashkent, ) and $BC_2$($F_1$ ${\times}$ G38F-1) of the kenaf cross were grown at the Crops Experiment Station, Suwon, Korea in 1965. Color of stems, petioles and capsules, and shape of leaves were noted to be simply inherited as a single factor. Red stem color was dominant over green stem color, red petiole color was dominant over green petiole, lobed shaped leaves were dominant over unlobed shaped leaves and yellow capsules were dominant over green capsule. It was, also, noted that the factor for color of petiole was linked with the factor for shape of leaf with a 11.9587 percent recombination value, however no interaction or linkage were found among the color of stem and capsule color. Using Powers partitioning method, theoretical means and frequency distributions for each population, the days to flowering were calculated with the assumption that two gene pairs were involved. The values obtained fitted the theoretical values. In general this would indicate that Dashkent and G 38 F -1 were differentiated by two gene pairs. Heritability values were calculated as the percent of additive genetic variance. Heritability value of days to flowering, 89.5% in the broad sense and 79.91% in the narrow sense, indicated that the selection for this character would be effective in relatively early generations. Particularly, high positive correlations were found between days to flowering and the color of petioles and shape of leaves. However, there was no relation between days to flowering and capsule color nor between these and stem color. On the basis of the results of this experiment there is evidence that the hereditary factor for shape of leaves and the color of petioles is linked with an effective factor or factors for the characters of days to flowering. The association was sufficiently close to offer a possible simple and efficient means of selection for moderately early mat. uring plants by leaf shape and petiole color selection. Again using Powers partitioning method the frequency distribution for each population to the fiber weight were calculated with the assumption that two gene pairs, AaBb, were involved. Both phenotypic and genotypic dominance were complete. The obtained value did not agree with the theoretical value for $F_2$ and $BC_1$ ($F_1$ ${\times}$ Dashkent.) It seems that Dashkent and G 38 F-1 were differentiated by two major gene pairs but some the other minor genes are necessary. It is certain that the hereditary factor for shape of leaves and color of petioles is linked with an effective factor or factors for fiber weight. Also, high. yielding plants with moderately early maturity were found in the $F_2$ population. Thus, simultaneous selection for high-fiber yield and moderately early maturing plants should be possible in these populations. Phenotypic and genotypic correlation coefficients between fiber weight per plant and days to flowering, stem height and stem diameter were calculated. In general, genotypic correlations are higher than the phenotypic correlation. The highest correlation is found between stem height and fiber weight per plant (0.7852 in genotypic and 0.4103 in phenotypic) and between days to flowering and fiber weight per plant (0.7398 in genotypic and 0.3983 in phenotypic.) It was also expected that the selection of high stem height and moderately early maturing plants were given the efficient means of selection for high fiber weight.

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