• Textile Coloration and Finishing
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• v.17 no.5 s.84
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• pp.53-60
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• 2005

Fusing press m/c is used for heating and pressing the specimens that are fed into between the two moving belts. Therefore the belt movement, belt temperature, and the pressure between belts must be kept constant. Especially, the belts should move in a limited operation range. When the belts run far out of the operation point, the machine has to be stopped, which results in a product defect because the fusing conditions, e.g., temperature and pressure, change during the transient process time period. It is important to avoid the belt stopping by maintaining the belt movement in a limited range. This study reports about the movement of the endless fusing belt in a long-span roller fusing m/c. The belt position changes as the 1st-order system does; if the roller axes are slanting each other with a certain angle, the belt running around the two rolls shows a dynamic behavior with the time that deviates fastly at the beginning from the initial condion and slows down. Then it reaches at a final position. The skewer the axes, the greater the position change. The inital change rate of the belt becomes large as the skewness of the axes between the two rollers increases.

• The Korean Journal of Nuclear Medicine
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• v.3 no.1
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• pp.1-12
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• 1969

Liver functions in diffuse parenchymal liver disease such as cirrhosis of the liver depend largely on the effective hepatic blood flow rather than on the individual cell functions. Clinical methods of measuring the hepatic blood flow were developed recently by the application of colloidal disappearance rate. In order to correlate the radiogold disappearance rate to conventional biochemical liver function tests, 21 normal subjects and 80 cases of cirrhosis of the liver were studied with both methods. The results are summarized as following: 1. The validity of external counting method to measure the blood disappearance rate of colloidal radiogold was confirmed by in vitro counting of the serial blood samples. 2. The blood disappearance rate of collidal radiogold was essentially the same. as the liver uptake rate of colloidal radiogold in normal and cirrhotic subjects with various degrees of functional disturbance. And it seemed there was no serious extrahepatic removal of the colloidal radiogold. 3. The disappearance rate of colloidal radiogold was not significantly changed by the posture change, but was enhanced by ingestion of 500 ml of water. 4. The disappearance rate of colloidal radiogold was not influenced by single dose of Telepaque, while BSP retention was increased after Telepaque. 5. The mean disappearance half time of colloidal radiogold in normal subjects was $2.49{\pm}0.391$(S.D.) minutes. The mean normal disappearance rate constant (K value) was $0.285{\pm}0.0428$(S.D.)/minute. 6. The colloidal radiogold disappearance half time was abnormally prolonged (over 3.2 min.) in $87.7{\pm}3.68$(S.D.) % of cirrhotic subjects. 7. In patients of liver cirrhosis the blood disappearance rate of colloidal radiogold correlated well to serum albumin and globulin levels and BSP retention which were considered to reflect functions of hepatic parenchymal cells. There was, however, no correlation between colloidal disappearance rate and thymol turbidity test, serum glutamic pyruvic transaminase, and serm alkaline phosphatase activities. The latters were considered to be associated with the activity of liver disease.

• Journal of Photoscience
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• v.11 no.1
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• pp.29-33
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• 2004

The mechanism of interaction of cyanocobalamin (CB) with bovine serum albumin (BSA) has been investigated by spectrofluorometric and circular dichroism methods. Association constant for the CB-BSA system showed that the interaction is non-covalent in nature. Binding studies in the presence of an hydrophobic probe, 8-anilino-l-naphthalene sulphonic acid, sodium salt (ANS) showed that there is hydrophobic interaction between CB and ANS and they do not share common sites in BSA. Stern-Volmer analysis of fluorescence quenching data showed that the fraction of fluorophore (protein) accessible to the quencher (CB) was close to unity indicating thereby that both tryptophan residues of BSA are involved in drug-protein interaction. The rate constant for quenching, greater than $10^{10}$ $M^{-1}$ $s^{-1}$, indicated that the drug binding site is in close proximity to tryptophan residue of BSA. Thermodynamic parameters obtained from data at different temperatures showed that the binding of CB to BSA involves hydrophobic bonds predominantly. Significant increase in concentration of free drug was observed for CB in presence of paracetamol. Circular dichroism studies revealed the change in helicity of BSA due to binding of CB to BSA.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.892-901
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• 2018

Because of excellent electrical properties, epoxy resin is widely used in packaging and casting power equipment. Moisture and temperature in the environment are inclined to seriously affect the insulation tolerance of epoxy resin. This work focuses on the aging characteristics of epoxy resin in hygrothermal environment. Scanning electron microscopy images show that there are micro-crack, micro-slit and holes inside aged samples. The moisture absorption process undergoes three equilibrium stages and it does not follow the Fick's second law. Observing the change of hydrogen bonds in the infrared spectra of the dried samples, it is found that chemically moisture absorption immerges when the physical moisture absorption entered the third equilibrium stage. By Debye equation to fit the imaginary part of the dielectric constant, it is concluded that the uniformity of water molecule has a great influence on the electrical conductivity loss. Furthermore, the polarization loss can be more easily affected by water molecules than small free molecules. After the aged samples being dried, their real and imaginary part of the dielectric constant descend, but their original electrical properties cannot completely restored. After chemical moisture absorption appears inside the material, the residual space charges increase significantly and the charge dissipation rate slow down obviously.

• International Journal of Automotive Technology
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• v.8 no.5
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• pp.623-628
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• 2007

Reliability analysis based on fracture mechanics requires knowledge of the on statistical parameters m and C in the fatigue crack growth law $da/dN=C({\Delta}K)^m$. The purpose of the present study is to investigate if it is possible to explain the change of parameter m by the fluctuation of C only. In this study, we apply the Paris-Erdogan law treating the parameter C as random and the parameter m as constant. Fluctuations in crack growth rate are assumed to be dependent only on C. The material resistance to fatigue crack growth(Z=1/C) is treated as a spatially random process, that varies along the crack path. The theoretical crack growth rates at various stress intensity factors are discussed. Additionally, the results of constant ${\Delta}K$ fatigue crack growth tests are reported for the structural steel, SM45C. The experimental data have been analyzed to determine the probability distribution of fatigue crack growth resistanc.

• Journal of Ceramic Processing Research
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• v.20 no.6
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• pp.603-608
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• 2019

In this study, the multilayered thin films of (Ba,Sr)TiO3/K(Ta,Nb)O3 were fabricated by the sol-gel and spin coating methods, and their structural and electrical properties were investigated. The specimen showed polycrystalline X-ray diffraction (XRD) characteristics with a tetragonal structure. The average grain size and film thickness for one coating were about 30~40nm and 60nm, respectively. The phase transition temperature of specimen was lower than 10 ℃. The dielectric constant and loss at 20 ℃ of the specimen coated six times were 1,231 and 0.69, respectively. The rate of change in dielectric constant at an applied direct current (DC) voltage of the six times coated thin films was 17.3%/V. The electrocaloric effect was the highest around the temperature at which the remanent polarization rapidly changed. When an electric field of 660kV/cm was applied to the triply coated thin films, the highest electrocaloric property of 4.41 ℃ was observed.

• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.451-459
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• 2017

There are many researches showing that when a process change has occurred, variable sampling intervals (VSI) control chart is better than the fixed sampling interval (FSI) control chart in terms of reducing the required time to signal. When the process engineers use VSI control procedure, frequent switching between different sampling intervals can be a complicating factor. However, average number of samples to signal (ANSS), which is the amount of required samples to signal, and average time to signal (ATS) do not provide any control statistics about switching performances of VSI charts. In this study, we evaluate numerical switching performances of multivariate VSI EWMA chart including average number of switches to signal (ANSW) and average switching rate (ASWR). In addition, numerical study has been carried out to examine how to improve the performance of considered chart with accumulate-combine approach under several different smoothing constant and sample size. In conclusion, process engineers, who want to manage the correlation coefficients of related quality variables, are recommended to make sample size as large and smoothing constant as small as possible under permission of process conditions.

• International Journal of Reliability and Applications
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• v.15 no.2
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• pp.125-150
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• 2014

Accelerated life tests (ALTs) are extensively used to determine the reliability of a product in a short period of time. Test units are subject to elevated stresses which yield quick failures. ALT can be carried out using constant-stress, step-stress, progressive-stress, cyclic-stress or random-stress loading and their various combinations. An ALT with linearly increasing stress is ramp-stress test. Much of the previous work on planning ALTs has focused on constant-stress, step-stress, ramp-stress schemes and their various combinations where the stress is generally increased. This paper presents an optimal design of ramp soak-stress ALT model which is based on the principle of Thermal cycling. Thermal cycling involves applying high and low temperatures repeatedly over time. The optimal plan consists in finding out relevant experimental variables, namely, stress rates and stress rate change points, by minimizing variance of reliability function with pre-specified mission time under normal operating conditions. The Burr type XII life distribution and time-censored data have been used for the purpose. Burr type XII life distribution has been found appropriate for accelerated life testing experiments. The method developed has been explained using a numerical example and sensitivity analysis carried out.

• Bulletin of the Korean Chemical Society
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• v.24 no.8
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• pp.1135-1140
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• 2003

The kinetics and mechanism of the pyridinolysis $(XC_5H_4N)$ of Y-aryl phenyl isothiocyanophosphates (1;$(YC_6H_4O)\;(C_6H_5O)$P(=O)NCS) are investigated in acetonitrile at 55.0 ℃. The Hammett plots for substituent (Y) variations in the substrate (log k₂ vs σY) exhibit a convex upward biphasic type with breaks at Y = H. For electron-donating Y groups the Hammett coefficients, ρY, are positive and cross-interaction constant ρXY is negative, while those for electron-withdrawing Y groups ρY values are negative with a positive ρXY. These results are interpreted to indicate mechanistic change at the breakpoint (σY = 0) from a concerted to a stepwise mechanism with rate-limiting expulsion of the $^-NCS$ group from a trigonal bipyramidal pentacoordinated (TBP-5C) intermediate. Biphasic plots of log k₂ vs σX or $pK_a$(X) with steeper slopes for the more basic nucleophiles are obtained suggesting an equatorial nucleophilic attack in contrast to an apical attack for the less basic nucleophiles with smaller magnitude of ρX or βx.

• Journal of the Korean housing association
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• v.19 no.1
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• pp.79-88
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• 2008

Hot water is used by having a wash, dishes, taking tub and drinking water in residential buildings, and the use objective is to raise comfort of human body sense, washing and sterilization effect and so on. Cold & hot water supply system is understanded simpler than HVAC systems relatively, so it is true that pace of performance improvement is slower than other systems for plan and technical development. In this study, the performance evaluations are conducted under the condition of composition ratio by 1:1 for cold & hot water supply manifold system using functionally complex valves such as constant flow regulating valve and 3-way mixing valve in the area of $105.6m^2$ apartment which consist of the largest part of the whole apartment. Also, flow rate related to simultaneous use of faucets and change of hot water temperature are compared with the existing method.