• Tribology and Lubricants
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• v.2 no.1
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• pp.53-60
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• 1986

The methods to prevent or suppress the initial failure of the sliding surfaces by the formation of the protection film during the manufacturing process were studied. Now it has been known that the surface protection film which was formed during the running-in process is mainly $Fe_3O_4$ and its film was formed only at the limited oxygen ability during the lubricated sliding. So it was tried to form the same oxide film before the sliding by heat treatment at 300$\circ$C with the wetted specimen by oil. The results show that a thin oxide film ($Fe_3O_4$) was formed on the surface beneath the solid oil film and the specimen with this film has much better friction properties than those prepared with heat treatment at 500$\circ$C and 700$\circ$C or the original one.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.5
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• pp.330-336
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• 2000

This study deals with the characteristic of refrigerant for heat-treatment deformation control of SM45C steel. The control of heat-treatment deformation must need the progress of production parts for a landing gear. Most of the deformation is occurred on unequal cooling. The unequal cooling is occurred by a property of quenching refrigeration. When a heated metal is deposited in the refrigeration, the cooling speed is so slow in early period of cooling because of occurring a steam-curtain. After more cooling, the steam-curtain is destroyed. In this progress, the cooling speed is very fast. The object of this study is to control the deformation of heat-treatment for landing gear by improving the conditions of quenching. The cooling curves and cooling rates of water, oil and polymer solution are obtained and illustrated. From the characteristics of the quenching refrigerant, the effects of heat-treatments on thermal deformation and fatigue strength are also investigated.

• Carbon letters
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• v.15 no.2
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• pp.129-135
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• 2014

Spinnable pitch for melt-electrospinning was obtained from pyrolized fuel oil by electron beam (E-beam) radiation treatment. The modified pitch was characterized by measuring its elemental composition, softening point, viscosity, molecular weight, and spinnability. The softening point and viscosity properties of the modified pitch were influenced by reforming types (heat or E-beam radiation treatment) and the use of a catalyst. The softening point and molecular weight were increased in proportion to absorbed doses of E-beam radiation and added $AlCl_3$ due to the formation of pitch by free radical polymerization. The range of the molecular weight distribution of the modified pitch becomes narrow with better spinning owing to the generated aromatic compounds with similar molecular weight. The diameter of melt-electrospun pitch fibers under applied power of 20 kV decreased 53% ($4.7{\pm}0.9{\mu}m$) compared to that of melt-spun pitch fibers ($10.2{\pm}2.8{\mu}m$). It is found that E-beam treatment for reforming could be a promising method in terms of time-savings and cost-effectiveness, and the melt-electrospinning method is suitable for the preparation of thinner fibers than those obtained with the conventional melt-spinning method.

• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.402-406
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• 2013

In this study, a pitch for melt-electrospinning was prepared from naphtha cracking bottom (NCB) oil by the modification with heat treatment. The softening point and property of the modified pitch was influenced by modification conditions such as nitrogen flow rate, heat treatment temperature, and reaction time. Among these, the heat treatment temperature had a very strong influence on the distribution of molecular weight and softening point of the pitch. The C/H mole ratio and average molecular weight increased with increasing the heat treatment temperature due the decomposition and cyclization reaction of surface-functional groups. In addition, the values of benzene insoluble and quinoline insoluble also tends to decrease, and the width of molecular weight distribution seems to get more narrow. The carbon fiber with a diameter of $4.8{\mu}m$ was prepared from a modified pitch at the softening point of $155^{\circ}C$ by melt-electrospinning. It is believed that the melt-electro spinning method is much more convenient to get the thinner fiber than the conventional melt spinning method.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.1-7
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• 2017

Forensic Engineering is the art and science of professionals qualified to serve as engineering experts in courts of law or in arbitration proceedings. Buses using compressed natural gas (CNG) trend to be extended in use internationally as optimal counterplan for reducing discharge gas of light oil due to high concern about environment. However, CNG buses is equipped with composite pressure vessels (CPVs); since the CPVs contain compressed natural gas, the risks in the case of accident is very high. In this study, the bursting test for the pressure vessel depending on the heat treatment conditions of the vessel in which the actual ruptured accident occurred, after the bursting test, the fracture pattern analysis had performed. The mechanical materials properties test using Instrumented Indentation Test had performed to confirm the mechanical properties for each heat treatment cases. Also, the fractography analysis and metallographic analysis had performed to find out the difference of each heat treatment case. By comparing normal vessel with abnormal vessel which have defect of heat treatment conditions in term of the bursting patterns and characteristics of containers using various forensic engineering methods, especially, it is possible to understand how important the heat treatment process is in the high pressure vessel unlike any product.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.5
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• pp.555-559
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• 2011

Oil hydraulic piston pumps are extensively used worldwide because of their simple design, light weight, and cost effectiveness. However, an oil hydraulic pump is likely to have high leakage, friction, and low energy efficiency after long-term use. In oil hydraulic piston pumps the clearance between the valve block and the piston plays an important role in the volumetric and overall efficiency. We studied the wear property of the SACM645 material used in hydraulic piston pumps via experiments with different heat treatments. We prepared three different specimens. The maximum tensile strengths of the QT and QT-nitration specimens are similar (about 820 MPa), but the strains are significantly different. However, the fatigue characteristic depended on the heat treatment.

• Korean journal of food and cookery science
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• v.8 no.2
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• pp.95-105
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• 1992

This study was carried on the Seasoning Oil production by Autoclaving Method in order to research a developed method. The Raw, Extract states of seasoning vegetables-Garlic, Onion and Ginger were added 40, 60% (w/w) of total amounts to corn salad oil. All samples treated with various conditions were determined physicochemical characteristics by Acid value, Peroxide value, Iodine value, Refractive Index, and Volatile Carbonyl Compound Content during incubating $(40{\pm}2^{\circ}C)$ and heating $(185{\pm}2^{\circ}C)$. The results were obtained as follws; 1. During incubation at $40{\pm}2^{\circ}C$, the order of antioxidative effects among seasoning vegetables was Ginger>Garlic>BHA>Onion and Extract state were more effective man Raw state. also the antioxidative effects of the seasoning vegetables were increased proportionally with the concentration in the Seasoning Oils. 2. In the case of heat treatment $(185{\pm}2^{\circ}C)$, AV, POV, IV and RI of each Seasoning Oil were changed very sharply. The antioxidative effect and Carbonyl Compound Content according to heat treatment differed from the type and concentration of seasoning vegetables in oil. Ginger had the most excellent antioxidative effect among seasoning vegetables, and m any case, the adding states of seasoning vegetables into oils were more effective in Extract man Raw states. 3. According to those results, each Seasoning Oil made from Garlic, Onion, Ginger was shown to have antioxidative properties specially in Ginger-Extract-Seasoning Oil. also the Autoclaving Method was thought to be rational method in preparation of Seasoning Oil.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.297-302
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• 2019

In order to investigate structural changes of the pyrolysis fuel oil (PFO), the volatile matters and heavy oil fractions were separated from PFO by heat treatment temperature. As a result of $^1H-NMR$ analysis of volatile matters, 1~2 ring aromatic compounds contained in the petroleum residue were mostly removed at a temperature before $340^{\circ}C$. Moreover, new peaks corresponding to aliphatic hydrocarbons were detected at the chemical shift of 2.0~2.4 ppm. It is attributed that the aliphatic hydrocarbon sidechain was cracked from the aromatic compound by the cracking reaction occurred at $320^{\circ}C$. The C/H mole ratio and aromaticity increased with increasing the heat treatment temperature. Therefore, from the structural analysis results of heavy oil fractions and volatile matters from PFO, the decomposition of the aliphatic sidechain by cracking reaction and the separation of volatile matters by boiling point of components were mostly affected structure changes of the PFO.

• Journal of Power System Engineering
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• v.22 no.6
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• pp.44-50
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• 2018

As a type of bolt with a spherical head, the ball stud is widely used as a part of a ball joint in steering or suspension systems in automobiles. Balls and studs are subjected to heat treatment suitable for each material; in particular, the shear strength of the ball stud must meet the specifications of the production company. This study evaluated the shear strength of joints according to the cooling method of ball studs subject to resistance welding. The shear stress of water cooling was higher than that of air cooling (as-received material). Note, however, th at oil cooling showed lower stress than that of as-received. When judged by standard deviation, mean, and coefficient of variation according to the arithmetic statistics and shape parameter as well as scale parameter, oil cooling is suitable.

• Korean journal of food and cookery science
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• v.10 no.1
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• pp.63-70
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• 1994

Oleoresin, 6-gingerol and 6,10-gingerol: 6-paradol= 1 : 1 mixture were extracted from ginger (Zingi-her of ficinale Roscoe) and changes of its antioxidant activity by heat-treatment were studed. Oleoresin was extracted with Ethanol-Ether and 6,10-gingerol : 6-paradol(1 : 1) and 6-gingerol were extracted with Hexane and Hexan : Ether= 1 : 1, respectively, and identified on the Thin-layer Chromatograpy (TLC) plate with the solvent system of Hexane Ether(1 : 4, v/v). And oleoresin was heat-treated during 0, 10, 30, 60, 120 minutes, and 6-gingercl and 6,10-gingerol . 6-paradol=1 : 1 were heat-treated during 0, 5, 10, 20, 40 minutes, respectively, at 140$^{\circ}C$ dry oven. To compare with antioxidant activity, oleoresins were added into soybean oil at 3fo level, 6-gingerol and 6,10-gingerol : 6-paradol= 1 : 1 at 0.1% level, BHT and TBHQ at 0.02% level, respectively. All the substrates treated were stored in a incubator at 45 2$^{\circ}C$ condition. The oxidative stability was estimated by the analysises of peroxide value and conjugated diene value during storage. The results were as follows: Antioxidant activity of oleoresins were considerably high and by heat-treatment were not decreased. 6-paradol was not show the antioxidant activity. 6,10-gingerol : 6-paradol=1 : 1 provided poor protection for soybean oil. Antioxidant activity of 6-gingerol was higher than 6,10-gingerol : 6-paradol=1 : 1 and by heat-treat-ment antioxidant activity was directly decreased. Relative antioxidant effectiveness(RAE) of each antio-xidant was compared. RhR was found to decrease as follow : TBHQ>oleoresin》BHT TBHQ》BHT>6-gingerol》6,10-gingerol : 6-paradol=1 : 1.