• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.617-621
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• 2003

Existing loudness models are specified only to diotic sounds in spite of the fact that normal human beings hear dichotic sounds. Approximately, the arithmetic mean of loudness values of both ear signals has been suggested for the resultant perceived loudness. In this study, the dependence of overall loudness perception on the interaural level differences was investigated by the subjective tests. It was found that the larger the interaural level difference, the louder the perception than the mean of calculated loudness values at both ears and the lower the critical band rate or the reference level, the louder the perception than the mean value. A modified loudness model was proposed to he applicable to dichotic sounds by using the equivalent diotic levels.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.4
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• pp.458-467
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• 2012

In this study, the linear viscoelastic response of a rectangular laminated plate is investigated. The viscoelastic properties, expressed by two basic spring-dashpot models, that is Kelvin and Maxwell models, is assumed in the range to investigate the influence of viscoelastic coefficients to mechanical behavior. In the present study, viscoelastic responses are performed for two popular equivalent single-layered theories, such as the first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT). Compliance and relaxation modulus of time-dependent viscoelastic behavior are approximately determined by Prony series. The constitutive equation for linear viscoelastic material as the Boltzmann superposition integral equation is simplified by the convolution theorem of Laplace transformation to avoid direct time integration as well as to improve both accuracy and computational efficiency. The viscoelastic responses of composite laminates in the real time domain are obtained by applying the inverse Laplace transformation. The numerical results of viscoelastic phenomena such as creep, cyclic creep and recovery creep are presented.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.2
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• pp.233-243
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• 2015

Controlled broadband acoustic scattering laboratory experiments were conducted using a linear chirp signal (95-220 kHz), and x-ray images of live and model fish with an artificial swim bladder were analyzed to investigate the changes in orientation and frequency dependence of target strength (TS) due to morphological differences in fish swim bladders. The broadband echoes from live and model fish were measured over an orientation angle range of ${\pm}45^{\circ}$ in the dorsal plane and in approximately $1^{\circ}$ increments. The location of nulls in the simulated echo response of the SINC [sinc function] model was overlaid on the TS map, showing the orientation and frequency dependence of fish TS, and they matched very well. It was possible to infer the equivalent fish scattering size (or swim bladder) using the null spacing in the experimentally obtained broadband TS map. Good agreement was observed for inferring the equivalent scattering size between the SINC model and the broadband echoes measured for the three fish species (black scraper Thamnaconus modestus; goldeye rockfish Sebastes thompsoni; and whitesaddled reef fish Chromis notatus). Some results of this inference are discussed.

• Journal of the Korean Wood Science and Technology
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• v.22 no.2
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• pp.54-60
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• 1994

The pine bark from mechanical pulp industry was cooked with bisulfite liquor, and the chemical and physical properties of the spent liquor after cooking for 90 minutes, which allowed partial defibration were determined. Lignosulfonate or lignin-related materials in the spent liquor have a molecular weight of approximately 3,000, which is lower than that of commercial lignosulfonate (C-LS) prepared from wood. The sulfonic equivalent weight calculated by colloid titration was 307 for C-LS, 238~239 for spent liquor. The contents of lignosulfonic acid and phenolic hydroxyl groups on $C_9$ unit of lignin in the spent liquor were 0.98~0.99, and 1.51~1.66, respectively. These values were remarkably higher than those of C-LS. Especially the content of phenolic hydroxyl group was almost twice that of C-LS. The viscosity of spent liquor after freeze drying was very low compared to C-LS. The dispersing ability of spent liquor was almost equivalent to or more than that of C-LS.

• The Korean Journal of Physiology
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• v.28 no.2
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• pp.233-240
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• 1994

In this study, it was investigated whether immortalized proximal tubule cells transformed with pRSVT could survive through the numerous passages. Results were as follows: 1. The cells transfected with pRSVT formed rapidly growing, multilayered colonies within 2 weeks in a hormone defined medium. Domes were also observed in some of the cultures. 2. r-glutamyl transpeptidase activity was equivalent to that observed in primary renal proximal tubule cell cultures. 3. Transformed cells with pRSVT form tubules in matrigel following 20 passages. 4. Genomic DNA of transformants was digested with either the restriction enzyme Xba or BamH1. A band of approximately 7.5kb was detected with Xba. Three BamH1 bands were detected at approximately 15 kb, 6.5 kb, and 3 kb.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.3
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• pp.35-43
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• 2012

Medium size rotorcraft consist of approximately 5,000 key components. The components must satisfy the target weight and performance requirement through optimization. Therefore a rotorcraft component has approximately 100 times higher unit cost for mass production than the equivalent of an automobile's, along with huge development cost. Configuration management consists of four main parts : configuration identification, configuration control, configuration audit, and data management. In development programme, configuration management is one of the methods to save development cost, and setting a well-structured configuration management system according to the Military Standard is an important factor in success of the programme. The paper proposes a configuration management system suitable for development of various multi-use components development and presents that the configuration management was performed successfully during dual-use component development programme using the established system.

• Korean Journal of Pharmacognosy
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• v.20 no.3
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• pp.162-169
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• 1989

Tissue culture of the roots of Panax ginseng was carried out to enhance the production of ginseng callus as well as to increase its contents of ginsenosides. A long cylinder type callus mass was formed when cultured IK callus by rotary shaking culture method, the growth ratio of the callus being 7.71 which was approximately 4 fold higher than those obtained by other culture methods. Ginsenosides $Rg_1$, Re and $Rb_1$ could be detected from the callus mass by TLC, however, their total contents were revealed to be approximately 9% compared to that of the fresh ginseng root equivalent by HPLC analysis,.

• Journal of Plant Biology
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• v.39 no.4
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• pp.257-263
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• 1996

Flower-inducing activity in the phloem exudata of Pharbitis cotyledons was investigated using the bioassay of Pharbitis and Lemna. By SDS-PAGE and 2-D gel electrophoresis of the phloem exudate, two polypeptides of 11 kDa and of approximately 32 kDa (pI 6.9) showing qualitative changes during the flower induction were detected. A polypeptide of approximately 20 kDa (pI 4.8) specifically labeled in vivo with [35S]methionine was found during the inductive dark period in Pharbitis cotyledon tissues. The polypeptide of the equivalent molecular mass and with the identicl pI value was also detected by in vitro translation assay. Thus, it is assumed that the 20 kDa polypeptide plays a role in the process of flower induction in Pharbitis cotyledons.

• Korean Journal of Mathematics
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• v.27 no.3
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• pp.661-690
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• 2019

The soft compactness notion via soft topological spaces was first studied in [10,29]. In this work, soft semi-open sets are utilized to initiate seven new kinds of generalized soft semi-compactness, namely soft semi-$Lindel{\ddot{o}}fness$, almost (approximately, mildly) soft semi-compactness and almost (approximately, mildly) soft semi-$Lindel{\ddot{o}}fness$. The relationships among them are shown with the help of illustrative examples and the equivalent conditions of each one of them are investigated. Also, the behavior of these spaces under soft semi-irresolute maps are investigated. Furthermore, the enough conditions for the equivalence among the four sorts of soft semi-compact spaces and for the equivalence among the four sorts of soft semi-$Lindel{\ddot{o}}f$ spaces are explored. The relationships between enriched soft topological spaces and the initiated spaces are discussed in different cases. Finally, some properties which connect some of these spaces with some soft topological notions such as soft semi-connectedness, soft semi $T_2$-spaces and soft subspaces are obtained.

• Journal of Radiation Protection and Research
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• v.12 no.2
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• pp.37-50
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• 1987

The exposure of the population in the United States to ionizing radiation has recently been evaluated by the National Council on Radiation Protection and Measurements (NCRP). This was done by constituting six organizational groups to address various phases of the work and the results of this work are summarized in this article. The article is based on the report, by the same title, which is scheduled for publication by the NCRP in September, 1987. The six organizational groups are titled Radiation Exposure from Consumer Products, Natural Background Radiation, Radiation Associated with Medical Examinations, Radiation Received by Radiation Employees, Public Exposure from Nuclear Power, and Exposure from Miscellaneous Environmental Sources. These titles are descriptive of the subject areas covered by each of these separate groups. The data evaluated are for the years 1977-1984 with the majority of the data being for the period 1980-1982. Summary information is presented and discussed for the number of people exposed to given sources, the effective dose equivalent, the average effective dose equivalent to the U.S. population, and the genetically significant dose equivalent. The average annual effective dose equivalent from all sources to the U.S. population is approximately 3.6 mSv (360 mrem). Exposures to natural sources make the largest contribution to this total. Radon and radon decay products contribute 2.0 mSv (200 mrem) whereas the other naturally occurring radionuclides contribute 1.0 mSv (100 mrem). Among man-made or enhanced sources, medical exposures make the largest additional contributions, namely 0.39 mSv (39 mrem) for diagnosis and 0.14 mSv (14 mrem) for nuclear medicine. It was not possible to evaluate exposures for therapy. Most of the other sources of population exposure, including nuclear power and consumer products, are minor. A possible exception would be the use of tobacco products. These exposures are discussed in relation to a negligible individual risk level of $10{\mu}Sv/y$ (1 mrem/y). The NCRP considers exposures below the negligible individual risk level as trivial and as such should be dismissed.