• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.3
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• pp.405-413
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• 2015

Acoustic target strength (TS) measurement and theoretical acoustic scattering models were applied to estimate the TS for assessing the fish biomass. TS measurement was made of ex situ sailfin sandfish Arctoscopus japonicus at 70 and 120 kHz, and then compared to backscatter model prediction. The live sandfish was tethered in seawater using monofilament lines. Measurements were made versus incidence angle, $-50^{\circ}$ to $50^{\circ}$ relative to dorsal aspect directions. Distorted wave Born approximation (DWBA) model was used to calculated TS pattern. The TS values of sandfish (body length: 16.2 cm) at 70 and 120 kHz were -66.94 dB and -64.45 dB, respectively, and were about 20 dB lower than TS of other fishes in Korea waters. These TS levels were distributed within the range of the theoretical TS. Ex situ measurement and theoretical TS may be applied to improve acoustical detection and biomass estimation of the sandfish, and is necessary to measure with various lengths.

• Journal of Industrial Technology
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• v.23 no.A
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• pp.149-156
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• 2003

The development and maintenance of a sound bond are essential requirements of concrete repair and replacement. The bond property of a overlay to its substrate concrete during the lifetime is one of the most important performance requirements which should be quantified. A standard or a verified bond strength measurement method is required at field for screening, selecting materials and quality control for overlay or repair materials, but no test method has been adopted as a standard. In this study, a concrete pull off bond strength measurement method for field application is proposed and evaluated. This study compares the splitting tensile test, slant shear test, nipple pipe direct tensile test, flexural adhesion test, briquette tensile test, jumbo nail pull-out test and core pull-off test with their test procedures. From these comparison and investigation, core pull-off test is selected as a main topic of this study because of it's suitability for in situ testing, simplicities in field application and clearness at interface boundary condition. Thus, the proposed core pull off test is evaluated to be the most appropriate method for field application in a simple manner. The fracture surface and fracture mode could be easily determined by visual observation of failure surface of the field specimen. The core pull off test was found to be sensitive to surface condition and latex contents at latex modified concrete.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.9
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• pp.1030-1038
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• 2007

This paper presents the measurement results of strength of electromagnetic wave for GSM-900/GSM-1800 band which is used in Europe. The Giryong village and Sosan field are selected as candidate regions according to the measurement results in Gijang-gun, Busan. The vertical polarizations is about 12 dBm higher than horizontal polarization at two candidate places, and it is measured 25 dBm lower than urban. The maximum value of measured strength of vertical polarizations in the cellular/GSM-900 bands are -65 dBm at Giryong village and -69 dBm at Sosan field, respectively. The maximum value of measured results of PCS/GSM-1800 bands are -90.5 dBm at Giryong village and -85 dBm at Sosan field, respectively, We confirm that the receiving strength of electromagnetic wave are very weak below -65 dBm at two candidate places and the signals of GSM frequency bands not affect to conversional system, then it is considered as a suitable place for GSM mobile field test.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.4
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• pp.345-353
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• 2004

Target strength (TS) of Japanese common squids (Todarodes pacificus) were measured using 38 and 120 kHz split beam scientific echosounders under the live condition. For the TS measurement of an individual, a total of 3 squids (mantle length (ML): 22.8, 25, and 27 cm) were used using small fishhook method, whereas for measurement of swimming angle, a total of 8 squids (ML: 21-27 cm) were used under live condition, confined with net cage with 2 m diameter At the same time, two underwater video cameras enabled continuous monitoring of squid behavior. Considering normal behavior, the mean TS at 38 and 120 kHz varied from -48.6 to -45.9 dB, and from -46.5 to -44.6 dB, respectively In both frequencies, mean TS at 120 kHz is relatively higher than that of 38 kHz, approximately 1.3-2.5 dB. From free living condition, the mean swimming angle of the squlds was $-24^{\circ}$. The results of the measurement will be provided basic information for conducting acoustic surveys of the squid.

• Journal of the Korean Applied Science and Technology
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• v.39 no.5
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• pp.614-622
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• 2022

This study attempted to investigate the effect of manufacturing a formulation with lavender extract and applying it to damaged hair. The experimental material was prepared by adding 0 g, 3 g 6 g, and 9 g of lavender extract to the perm base agent. The prepared formulation was applied to four damaged hair samples and compared and analyzed. As a measurement method for the effect on damaged hair, tensile strength, absorbance using methylene blue, and gloss were measured. Statistical analysis was conducted for the reliability of the research results. The tensile strength measurement results showed that the tensile strength of the sample applied with a formulation containing 6 g and 9 g at 8 levels increased, affecting damaged hair. As a result of absorbance analysis using methylene blue, it was found that the absorbance of all samples applied by adding extracts decreased, affecting damaged hair. The gloss measurement results showed that the addition of 9 g affected the damaged hair. In conclusion, it can be seen that lavender extract affects damaged hair, so it is considered to have an effect of improving Damage hair.

• Journal of the Korean Applied Science and Technology
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• v.41 no.1
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• pp.36-45
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• 2024

This study was to investigate the effect of manufacturing an avocado oil-added formulation and applying it to damaged hair. The experimental materials were prepared by adding avocado oil contents of 0 g, 3 g, 6 g, and 9 g to the perm base agent. It was applied to 4 damaged hair samples with the prepared formulation for comparative analysis. Tensile strength, absorbance using methylene blue, and gloss were measured as measurement methods for the effect on damaged hair. Statistical analysis was performed for the reliability of the research results. As a result of the tensile strength measurement, it was found that the tensile strength of the sample applied with the formulation containing 6 g and 9 g to the sample increased, affecting damaged hair. As a result of the absorbance analysis using methylene blue, it was found that the absorbance of all samples applied by adding oil decreased, affecting damaged hair. The gloss measurement result was found to affect damaged hair when 6 g and 9 g were added. The conclusion is that avocado oil affects damaged hair, so it is thought that it will have an effect of improving hair.

• Corrosion Science and Technology
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• v.13 no.5
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• pp.186-194
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• 2014

Establishment of adhesion strength measurement procedure for marine epoxy coatings was conducted in order to ensure reliability of the test results. It was found that (1) the increase in thickness of the substrates would induce increase of pull-off strength. Especially, the increase in adhesion strength with the substrate thickness increment was attributed to the transition of stress mode to the pure tensile mode excluding bending effect. (2) The longer curing time, the higher pull-off strength. It may be due to higher cross-linking density of the coating (3) The pull-off strength increases as coating thickness increases due to the diminishment of bending effect (4) The longer drying time after water immersion, the higher pull-off strength. It may be due to the evaporation of water molecule at the coating-substrate interface.

• Journal of the Korean Ceramic Society
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• v.35 no.2
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• pp.185-195
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• 1998

This experiment carried out in order to investigate the effect of the chemical activators for acceleration of hydration the system of Fly ash-Cao The paste was consisted of 80wt% Fly ash and 20wt% CaO with 1. 3. 5wt% of 4 activators(N{{{{ alpha _2 }}S{{{{ OMICRON _4 }}, CaC{{{{ {l }_{2 } }}, NaOH, Ca(N{{{{ OMICRON _3 {)}_{2 } }} and W/S ratio of 0.42 After curing for 1, 3, 7, 14, 28 days the paste hydration was characterized by the measurement of compressive strength XRD analysis SEM observation the combined water and the reaction amount of Ca(OH)2 determination. As a result of this ex-periment all of the system which involved Na2SO4 or NaOH had a god compressive strength. In the case of 7 days curing a system which added CaCl2 showed the highest compressive strength among all especially NaOH system showed a high increase in strength as a dosage of it increased. Hydration products were different according to activatores added. Only C-S-H was observed in NaOH system. As the reaction amount of Ca(OH)2 and combined water were increased the compressive strength increased. There were few differences in the comparision of strength between ignited loss 3.1% and loss 9.3% of fly ash.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.617-625
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• 2009

The primary purpose of this study was to compare the hamstring-to-quadriceps strength(H/Q) ratios in collegiate soccer players and normal age-matched healthy students, and the secondary purpose was to investigate the changes in the H/Q ratio according to the degree of knee flexion. Twenty-five subjects volunteered to participate in this study. The study group comprised 12 healthy male collegiate soccer players, and the control group, 13 healthy age-matched male collegiate students. The modified N-K table was used for isometric strength measurement(unit: N). Mann-Whitney tests were performed to determine the differences in the H/Q ratios of soccer players and age-matched students at different knee flexion angles of the dominant leg. The strength of the hamstring muscle in the study group was significantly lower than that observed in the control group at knee flexion angles of $60^{\circ}$ (p<.001), $90^{\circ}$ (p<.01), and $120^{\circ}$ (p<05). The strength of the quadriceps muscle in the study group was significantly higher than that observed in the control group at flexion angles of $30^{\circ}$ (p<.001) and $60^{\circ}$ (p<.05). The H/Q ratios in the study and control groups differed significantly at all angles ($60^{\circ}$, p<.001, $90^{\circ}$, p<.001 and $120^{\circ}$, p<.001).

• Journal of the Korean Wood Science and Technology
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• v.31 no.3
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• pp.35-41
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• 2003

The mechanical and physical properties of wood are strongly dependent upon the slope of grain. Specially, tensile strength is more severely affected by the slope of grain. Therefore, tension tests were performed on small thin wood samples made from Pinus radiata with varying the slope of grain. Determining the tensile strength for clear thin wood samples the other variabilities associated with material, size, drying, defects, etc were discarded. Slope of grain was measured by the slope of grain indicator and actual slope of grain was also determined by a protractor. Correlation coefficients between machine measured and actual slope of grain for 40 pieces of 2×20 mm, 300 mm long Pinus radiata were 0.84 for wide face measurement. Results also showed that tensile strength and MOE from stress wave tests decreased with increasing the slope of grain. This study did not establish a relationships for tensile strength and MOE from stress wave with slope of grain. However, the trends of MOEs from stress wave test with both slope of grain are agreed well with Hankinson's equation. Predicted tension strength curve by Hankinson's equation was also agreed well with the experimental data over the range from 0 to 13 degrees for slope of grain.