• Korean Journal of Environmental Agriculture
• /
• v.29 no.4
• /
• pp.396-401
• /
• 2010

Tolclofos-methyl is one of the most widely used organophosphorous pesticides in control of soil-borne diseases in ginseng field. In Korea, residues of tolclofosmethyl in ginseng and cultivation soil is quite often detecting. The objective of this study was to know the possibility for the accelerated degradation of tolclofos-methyl by various chemical treatment under soil slurry condition. The degradation of tolclofos-methyl was accelerated by zerovalent metals treatment in soil slurry. The degradation rate of tolclofos-methyl was found to be at higher zerovalent zinc than unannealed zerovalent and annealed zerovalent iron. The effect of different sizes of zerovalent iron on tolclofos-methyl degradation was showed that the smaller size of zerovalent iron, the greater the degradation rate. In aqueous solution of pH 4.0 below the degradation rate of tolclofos-methyl was very high. Under this experimental condition, tolclofos-methyl degradation was the greatest at 2% (w/v) of ZVI under 0.1 N of HCl in 24 hours, the degradation rate was 94.4%. By testing various chemicals, it was found that $Fe_2(SO_4)_3$ as iron source showed better for degrading tolclofos-methyl in $H_2O_2$ 500 mM treatment and sodium sulfite also showed the degradable possibility tolclofos-methyl in soil slurry.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.24 no.4
• /
• pp.325-330
• /
• 2004

Several kinds of low voltage cables have been used in nuclear power plants for the supply of electric power, supervision, and the propagation of control signals. These low voltage tables must be inspected for safe and stable operation of nuclear power plants. In particular, the degradation diagnosis to estimate the integrity of low voltage rabies has recently been emphasized according to the long use of nuclear power plants. In order to evaluate their degradation, the surrounding temperature, hardness of insulation material, elongation at breaking point (EAB), etc. have been used. However, the measurement of temperature or hardness is not useful because of the absence of quantitative criteria; the inspection of a sample requires turning off of the power plant power; and, the electrical inspection method is not sufficiently sensitive from the initial through the middle stage of degradation. In this research, based on the theory that the ultrasonic velocity changes with relation to the degradation of the material, we measured the ultrasonic velocity as low voltage cables were degraded. To this end, an ultrasonic degradation diagnosis device was developed and used to measure the ultrasonic velocity with the clothing on the cable, and it was confirmed that the ultrasonic velocity changes according to the degradation of low voltage cables. The low voltage cables used in nuclear power plants were degraded at an accelerated rate, and EAB was measured in a tensile test conducted after the measurement of ultrasonic velocity. With the increasing degradation degree, the ultrasonic velocity decreased, whose potential as a useful parameter for the quantitative degradation evaluation was thus confirmed.

• Journal of Applied Reliability
• /
• v.17 no.1
• /
• pp.66-71
• /
• 2017

Purpose: Polymer capacitors are known to have very high reliability as compared with liquid electrolytic capacitors, but their capacity has been reported to decrease in charge and discharge at low temperature. The purpose of this study to clarify these characteristics. Methods: In order to clarify these characteristics, charging-discharging tests were carried out for 200 hours with three different capacities and at 5 different temperature from $5^{\circ}C$ to $100^{\circ}C$. Results: As a result of the test, it was confirmed that the capacity of the polymer capacitor was decreased with higher capacity and lower temperature. Conclusion: Such a failure phenomenon was caused by the shrinkage and expansion characteristics of the polymer used therein, it is presumed that this failure phenomenon is due to the complex pore structure made by etching.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.33 no.2
• /
• pp.198-204
• /
• 2013

Acoustic emission(AE) signal was detected during charge and discharge of lithium ion battery to investigate relationships among cumulative count, discharge capacity, and microdamages. AE signal was received during accelerated charge/discharge cycle test of a coin-type commercial battery. A number of AE signals were successfully detected during charge and discharge, respectively. With increasing number of cycle, discharge capacity was decreased and AE cumulative count was observed to increase. Microstructural observation of the decomposed battery after cycle test revealed mechanical damages such as interface delamination and microcracking of the electrodes. These damages were attributed to sources of the detected AE signals. Based on a linear correlation between discharge capacity and cumulative count, feasibility of AE technique for evaluation of battery degradation was suggested.

• Polymer(Korea)
• /
• v.32 no.5
• /
• pp.440-445
• /
• 2008

The failure mechanism and failure morphology of linear low density polyethylene (LLDPE) tubing under hydrostatic pressure were investigated. Microscopic observations using video microscope and scanning electron microscope indicate that the failure mode is a brittle fracture including cracks propagated from inner wall to outer wall. In addition, oxidation induction time and Fourier transform infrared spectroscopy results show the presence of exothermic peak and the increase in carbonyl index on the surface of fractured LLDPE tubing, due to thermal-degradation. An accelerated life test methodology and testing system for LLDPE tubing are developed using the relationship between stresses and life characteristics by means of thermal acceleration. Statistical approaches using the Arrhenius model and Weibull distribution are implemented to estimate the long-term life time of LLDPE tubing under hydrostatic pressure. Consequently, the long-term life time of LLDPE tubing at the operating temperature of $25^{\circ}C$ could be predicted and also be analyzed.

• Journal of KIISE:Information Networking
• /
• v.27 no.1
• /
• pp.76-87
• /
• 2000

ATM is a key technology of integration of multimedia service. Recently, Many study have been concentrated on performance testing for evaluation network performance are stronger everyday. The performance testing is on evaluation of maximal throughput of network by measuring and analyzing of various performance parameters. There are two ways to test ATM network performance; one is using QoS in cell level on the point of network's view, and the other is using metric in frame level in the point of user's view. And, the standardization process is also under way. In this paper, we derive a performance requirement of TCP in TCP/IP data transmission over ATM UBR service. By applying the derived requirements to ATM and packet networks, we evaluate the performance of TCP over UBR based on the result of our simulations. Therefore, we evaluate the result of simulation and find degradation of network throughput by interaction between TCP congestion control and ATM cell drop policy. So we suggest the accelerated Vegas that modify traditional TCP Vegas in congestion control mechanism for batter network throughput.

• Corrosion Science and Technology
• /
• v.2 no.5
• /
• pp.207-211
• /
• 2003

The weather resistance of five coatings systems based on alkyd, chlorinated rubber, epoxy, polyurethane and fluoropolymer were studied by natural exposure test and accelerated test. The coatings were exposed at Hanoi station with urban industry atmosphere and at Baichay station with marine atmosphere. The degradation of coatings was evaluated by gloss measurement and surface analysis by scanning electronic microscopy. The results obtained show that among coatings tested the gloss of polyurethane and fluoropolymer coatings remained highly and those of alkyd, chlorinated rubber and epoxy coatings were very low after two years of atmospheric exposure. Under accelerating conditions the gloss of fluoropolymer coatings remained highly after 80 cycles of testing. By comparison with accelerating test in UV-condensation chamber the conditions at atmospheric stations are more aggressive.

• Journal of Applied Reliability
• /
• v.10 no.4
• /
• pp.213-235
• /
• 2010

In this paper, we carried out an accelerated degradation test that is commonly used to predict characteristics life of rubber gaskets for a pole transformer. The potential failure mode applied for the test is rubber elongation and the corresponding failure mechanism is heat. From the result, we found that Weibull distribution is the fatigue life distribution in NBR and H-NBR. After estimating characteristics life in commonly used temperature, the average life span of $B_{50}$ in NBR is 7.7 years under $50^{\circ}C$ and the life span in H-NBR is 28 years.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07b
• /
• pp.1022-1025
• /
• 2002

This paper presents the reliability of planar InP/InGaAs avalanche photodiodes (APD's) with recess etching, which is very crucial for the commercial 10-Gb/s optical receiver application. A versatile design for the planar InP/InGaAs APD's and bias-temperature tests to evaluate long-term reliability at temperature from 200 to $250^{\circ}C$. The reliability is examined by accelerated life tests by monitoring dark current and breakdown voltage. The lifetime of the APD's is estimated by a degradation activation energy. Based on the test results, it is concluded that the planar InP/InGaAs APD's with recess etching shows the sufficient reliability for practical 10-Gb/s optical receivers.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.3 no.3
• /
• pp.122-131
• /
• 2003

In this study, some characteristics of conductive and non-conductive adhesive inter-connections are derived, based on data from literature and own projects. Assembly of flip chip on flex is taken as a carrier. Potential failure mechanisms of adhesive interconnections reported in literature are reviewed. Some methods that can be used to evaluate the quality of adhesive interconnections and to evaluate their aging behavior are given. Possible finite element simulation approaches are introduced and the required critical materials properties are summarized. Response to temperature and moisture, resistance to reflow soldering and resistance to rapid change in temperature and humidity are elaborated. The effect of post cure during accelerated testing is discussed. This study shows that only a combined approach using finite element simulations, and use of appropriate experimental evaluation methods can result in revealing, understanding and quantifying the complex degradation mechanisms of adhesive interconnections during aging.