• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.10
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• pp.1785-1792
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• 2003

Methods to predict fatigue crack growth are compared in a quantitative manner for crack growth test data of 2024- T351 aluninum alloy under narrow and wide band random loading. In order to account for the effect of load ratio, crack closure model, Hater's equation and NASGRO's equation have been employed. Load interaction effect under random loading has been considered by crack closure model, Willenborg's model and Wheeler's model. The prediction method using the measured crack opening results provides the best result among the prediction methods discussed for narrow and wide band random loading data.

• 제어로봇시스템학회:학술대회논문집
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• 1986.10a
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• pp.352-355
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• 1986

In this paper, some candidates suggested for the improvement of the robustness in adaptive control systems are shortly surveyed. Using dead zone concept of error in adaptation process, gain retardation methods such as .sigma.-modification and parameter restriction method are those considered. Feedforward compensation and normalized adaptation technique are also considered. New modeling technique suggested by Donati et al is used for the indirect control of plants containing unmodeled dynamics. The frequency band of input signal, which is used as a test signal and control signal simultaneously, is directly related to the control of plants containing high frequency parastics. Computer simulation results of the some selected algorithms are shown.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1044-1045
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• 2008

DC transit system has been adopted in the metropolitan area, Korea since 1974. EMU in this system always reiterates that acceleration and retardation. When EMU decelerates using electric breaking, regenerative power occurs. Regenerative power can be consumed in vicinity EMU on the same line or in resistor. If DC transit system has inverter for reusing regenerative power, Energy efficiency in DC transit system will be increased. This paper present the adoption of developed inverter in commercial railway line and the test result procedure of developed inverter is presented.

• Bulletin of the Korean Chemical Society
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• v.21 no.1
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• pp.61-64
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• 2000

FT-IR/ATR analysis shows that the oriental lacquer coating network degrades mostly in the unsaturated side chain. The rate of increase in carbonyl intensity (a measure of photodegradation) during the accelerated weathering test was substantially different for the unstabilized and stabilized samples; adding 2 wt% HALS into the oriental lacquer formulation enhanced photostabilization up to three times. Weight loss measurements, another indication of photodegradation, and SEM analysis support this conclusion. Despite the presence of the photo-stabilizer, the other properties of the lacquer were not significantly affected. In particular, the curing behavior of purified lacquer (PL) and HALS-stabilized samples is similar, although the in-situ DETA analysis showed that addition of HALS can slightly retard the cure reaction rate in oriental lacquer coating. It is hypothesized that this cure retardation may be related to the salt formation between HALS and acid of oriental lacquer.

• Journal of Genetic Medicine
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• v.2 no.2
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• pp.49-51
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• 1998

Wolf-Hirschhorn syndrome (WHS) is caused by a deletion of the short arm on chromosome 4 and is characterized by multiple congenital abnormalities, growth and mental retardation. In this case report, we performed amniocentesis for the chromosome analysis on a 25-year-old pregnant woman at 16 weeks of gestation whom we suspected of Edward's syndrome by the triple test of maternal serum and ultrasonography. The result of analysis revealed a karyotype of the fetus with 46,XY,del(4)(p15) by trypsin Giemsa's banding technique. With the result, we were able to diagnose the fetus as having WHS. As such, after therapeutic termination of the pregnancy, we confirmed WHS through the sampling of tissue by both trypsin Giemsa's banding and fluorescence in situ hybridization (FISH) method. To determine the origin of the WHS, we further tested the karyotypes of the parents. As parental karyotypes were found to be normal, we determined the case of the fetal WHS to be de novo.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.2
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• pp.78-84
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• 1997

Batch and column tests were performed to investigate the sorption capacity of bottom soils of Kimpo metropolitan waste landfill. Sorption capacity and sorption isotherm from the batch test for inorganic and heavy metal substances and retardation capacity of heavy metals from the column test are obtained. It was recognized from the tests that the samples match well with Freundlich isotherm and marine clay has good sorption capacity for potassium and heavy metals such as lead and cadmium. The soil samples with different geologic origins did not show significant differences in the sorption capacity of tested components.

• The Korean Journal of Nuclear Medicine
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• v.15 no.1
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• pp.37-43
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• 1981

Congenital hypothyroidism due to organification defect was first reported by Haddad and Sidbury in 1959. The organification defect is easily proved by perchlorate discharge test. We experienced a patient who had large goiter, growth and mental retardation, and revealed positive reponse to perchlorate discharges test, and the surgical biopsied specimen showed Huerthle cell adenoma, which was probably due to chronic stimulation of thyroid stimulating hormone, or coexisted incidentally. Described here a case of congenital hypothyroidism due to organification defect associated with Huerthle cell adenoma, with review of some literatures.

• Geotechnical Engineering
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• v.13 no.4
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• pp.75-84
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• 1997

In this paper, the retardation capacity of marine clay and weathered soil of seashore waste landfill is analyzed by using a laboratory column apparatus for organic and inorganic components which can represent the components of the leachate of municipal waste landfill. The results show that sorption capacity marine clay for potassium is larger than that of weathered soil. Lead and cadmium are adsorbed completely at concentrations higher than the real concentrations developed in the landfill. The bottom soils of seashore landfill can also retard some nondegradable components of organics although their sorption capacities for organics were less than those for inorganics.

• Journal of Fisheries and Marine Sciences Education
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• v.19 no.1
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• pp.91-100
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• 2007

The purpose of this study was to compare personality existed in the populations of the mentally retarded with and without Down syndrome. For this purpose, two research questions were proposed. (a) Is there any difference of personality existed between two groups? (b) Is there any difference of sub-personality existed between two groups by disability degree? Participants in this are 159 people with mental retardation(the mentally retarded with Down syndrom: 82, the mentally retarded without Down syndrom : 77) in P and S cities. First of all, the reliability in measurement instrument was verified through a pre-study. For the first research question, t-test was used. And two way ANOVA was used to investigate the second research question. The results of this study were as follows:First, according to the result of t-test, there were significant differences of personality scores between two groups. And there were significant differences between the mentally retarded with and without Down syndrome regard to expectation of success, outerdirectedness, positive or negative responding tendency, curiosity among sub-personality factors. Second, the result of the two way ANOVA analysis, no meaningful statistically difference in personality by degree of the impairment. But It showed difference regard to effectancy motivation, expectation of success, curiosity among sub-personality factors between the mentally retarded with and without Down syndrome by impairment degree.

• Journal of Drive and Control
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• v.18 no.2
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• pp.46-55
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• 2021

A forklift is a powered industrial vehicle used to lift and move materials over short distances. Nowadays, almost all forklifts are equipped with an automatic transmission due to its improved operator comfort and increased productivity. Thanks to marked improvement of transmission control unit equipped with highly-advanced microcontrollers, recently developed automatic transmission for forklift have various auxiliary functions such as creep, auto retardation, and automatic shift with excellent shift quality. This paper deals with the creep function which enables one to maneuver a forklift at the designated low speed by slip control of clutches. The design of creep function was based on four modes of creep operation depending on the status of the operator's shift lever and accelerator pedal. Control algorithms and control parameters for each mode were designed to achieve the desired static and dynamic performance. Vehicle test for the designed creep function was carried out with an independently developed embedded controller. Test results confirmed good creep speed control without speed error at a steady state with a mild shift shock during mode changes by stepping or releasing the accelerator.