• Animal cells and systems
• /
• v.6 no.4
• /
• pp.287-292
• /
• 2002

Functional characterization of sex pheromones in olfactory responses is essential for the study of chemical communications in amphibians. Using Y-maze olfactory preference tests, we have investigated the olfactory res-ponses of male and female red-spotted newts, Notophthalmus viridescens, to the crude extracts of the opposite sex's genial and cloacal pheromones. Both male and female cloacal pheromone extracts caused the opposite sex to initiate olfactory responses by leaving the starting area in the Y-maze, but only subject males exposed to female cloacal pheromone extracts completed olfactory choice by entering the side arm of the Y-maze which received the pheromones. For genial pheromone extracts, only female genial pheromone extracts induced initial olfactory responses from test males. Neither male nor female genial pheromone extracts made the oppo-site sex complete olfactory choice. Pre-exposure of test females to male pheromone extracts increased the likelihood of initial olfactory responses. The latency for initial olfactory responses of test females that were previously exposed to male genial extracts was significantly shorter than that of control females.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2008.03a
• /
• pp.301-306
• /
• 2008

A pyrogen igniter was designed to satisfy the required condition of kick motor system for the space launch vehicle. We analyzed the ignition characteristics and performed the combustion tests to verify the internal ballistic performance. In the design process, the arc-image test was carried out to find the sufficient heat flux as varying the initial pressure from 10 to 700kPa. The analysis indicated that the initial pressure condition would delay ignition time within a range from 100 to 500ms. The combustion test with an inert chamber was also performed to understand the ignition characteristics with the variation of the initial pressure of free chamber volume. Finally, we confirmed that the igniter could provide the acceptable energy to ignite the propellant of kick motor at the ground test. The result of the ground tests showed that the ignition delay time was within the design range at the atmospheric pressure condition.

• Structural Engineering and Mechanics
• /
• v.83 no.1
• /
• pp.109-121
• /
• 2022

Twelve push-out test specimens were conducted with various parameters to study the static and fatigue performance of a new through-bolt shear connector transferring the shear forces of interface between prefabricated hybrid fiber reinforced concrete (HFRC) slabs and steel girders. It was found that the fibers could improve the fatigue life, capacity and initial stiffness of through-bolt shear connector. While the bolt-hole clearance reduced, the initial stiffness, capacity and slippage of through-bolt shear connector increased. After the steel-concrete interface properties were improved, the initial stiffness increased, and the capacity and slippage reduced. Base on the test results, the equation of the load-slip curve and capacity of through-bolt shear connector with prefabricated HFRC slab were obtained by the regression of test results, and the allowable range of shear force under fatigue load was recommended, which could provide the reference in the design of through-bolt shear connector with prefabricated HFRC slabs.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.27 no.2
• /
• pp.119-127
• /
• 2023

In this paper, seismic performance evaluation was carried out for eight circular reinforced concrete columns designed seismically by KRTA[1]and KCI[8]. Primary design parameters for such columns included many longitudinal reinforcements, yield strength of reinforcements, the vertical spacing of spirals, aspect ratio, and axial force ratio. The test results showed that all the columns exhibited stable hysteretic and inelastic responses. Based on the test results, drift ratios corresponding to each damage state, such as initial yielding, initial cover spalling, initial core concrete crushing, buckling, and fracture of longitudinal reinforcement and final spalled region, were evaluated. Then, those ratios were compared with widely accepted damage limit states. The comparison revealed that the existing damage states were considerably conservative. This implies that additional research is required for the damage limit states of such columns designed seismically by current Korean design codes.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.6
• /
• pp.135-141
• /
• 1997

Low velocity impact test and compressive residual strength test after impact were performed by using Hercules AS4/3501-6[45/0/-45/90]$_{2s}$ laminated plate to investigate the low velocity impact damage behavior and the post-impact strength degradation on orthotropic composite laminate plate. Due to the lateral impact losd, the load path showed "" shape according to the laminate central deflection. Damage in a laminate occurs by inclined matrix crack at the damage initiation load stage and vertical matrix crack, occurs on the outer surface. Evaluating the compressive residual strength after the low velocty impact test, it could be found that there is a transient range where the compressive residual strength drop suddenly in the initial damage which is in the matrix crack range and the initial delamination area. is in the matrix crack range and the initial delamination area.

• The Korean Journal of Food And Nutrition
• /
• v.13 no.5
• /
• pp.434-439
• /
• 2000

This study was conducted to investigate the association between initial nutritional status and treatment outcome of hepatoma patients. Initial nutritional status was measured based on weight, serum albumin and total lymphocyte counts. Treatment outcome was measured in the three categories such as complication, treatment status at discharge and mortality. The study subjects were 120 patients with hepatoma cancer admitted at a university hospital in Seoul. The information about initial nutritional status and treatment outcome was collected from medical records. Chi-square test was used to test the association between initial nutritional status and treatment outcome As a result. 76.6% of the subjects were classified as the nutritional risk group based on initial nutritional states. Prevalence of complication was higher in nutritional risk group I and II than that in non-risk group(p<0.05). Death rare of the nutritional risk group was significantly higher than that of non-risk group(p<0.001). The findings suggest the strong association between the initial nutritional status and treatment outcome of hepatoma cancer.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.4
• /
• pp.145-151
• /
• 2014

Modern vehicle has a lot of ECU(Electronic Control Unit) products to control many parts such as engine, transmission, brake, body and so on. ECU quality is one of important factors related to vehicle quality and driver's safety. Based on Bath-tub curve which presents failure rate during product lifetime, we designed and applied Accelerated Run-in Test into manufacturing line by simulating stress amount to ECU and developing the required software and efficient test equipment for mass production. This test makes ECU products stressed through electrical and thermal stresses under excessive driving condition, which induce potential initial failure of components in the ECU during production. The outcome until these days proved that Acceleration Run-in Test have reduced initial failure rates and increased quality of ECU products in the field outstandingly.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.722-727
• /
• 2004

This paper includes the comparative study between Cr plating and nitriding process with an aim at improving corrosion, wear and maintainability for KNR(Korean Next Generation Rifle) 5.56mm barrel. The endurance test was conducted to compare the performance of standard barrel, Cr plating barrel and nitriding barrel. Main activities are described as follows; optimal Cr plating and nitriding process set-up for KNR 5.56mm barrel; durability test of each barrel(20,000 rounds); salt water immersion test; dispersion, initial velocity, inner diameter data acquisition. According to the results of this firing test, Cr plating barrel is superior to standard barrel and nitriding barrel in view of corrosion, wear and maintainability

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.2163-2173
• /
• 2011

In this study, the deformations and stresses occurred in the elastic rail fastening system were evaluated according to applied extreme track forces based on various field conditions, track curvature and poor properties. The purpose of this study is to establish a method for efficient management and suggest guide line for track construction in order to secure the performance quality of the elastic rail fastening system on the sharp curved track.. Therefore, initial construction qualities of rail and concrete bed, initial clamping force and applied extreme track forces were used into experiment as several parameters. Using these test results, the performance characteristics of the elastic rail fastening system were also evaluated. As a result, it suggested the method to secure long-term durability of fastening system and comparing sharp curved track to results on field test.

• Journal of Ocean Engineering and Technology
• /
• v.11 no.4
• /
• pp.40-48
• /
• 1997

There are many research results as individual uni-axial tension creep test of heat-resisting materials. However, there are very few about the study on the high temperature creep test for the Initial Strain Method, and especially any study on it about the friction welded joints of SUH3 to SUH35. One of the important concerns is a reliable method of evaluating static creep properties. No reliable method seems available at present to evaluate or predict static creep properties. So, the reliable method to evaluate and predict them by the ISM and AE techniques was made.