• Elastomers and Composites
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• v.49 no.2
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• pp.144-148
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• 2014

Compression set (CS) and weight loss by thermal degradation of the ACM rubber composite sample prepared for an automotive part were measured simultaneously at several given temperatures of $150^{\circ}C$, $160^{\circ}C$, $170^{\circ}C$, and $180^{\circ}C$. Using the relationship between them, thermal life of the sample could be predicted at a given operating temperature by applying Toops method which is based on the analysis of non-isothermal TGA thermograms. Conversion by weight loss showed a linear relationship with CS changes, exhibiting 4.2% at CS 40%. Activation energy of thermal degradation was calculated as 120.2 kJ/mol at 4.2% of weight loss from Flynn-Wall-Ozawa analysis. When the expected life was set as time to reach CS 40% at $120^{\circ}C$, the life time of the sample was calculated as 9,700 hrs when Toops method was applied.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.15 no.2
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• pp.244-251
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• 2002

Introduction: SLE is autoimmune disease to appear systemic pathology in the connective tissue. Perniotic LE is sub-type of chronic dermal LE which causes purple macules on the terminal part of body-nose, ends of fingers, heals, calfs of the legs, elbows and knees. Objective: The purpose of this study was to estimate the efficiency of oriental medical treatment and management on the SLE and perniotic LE. Subject: We studied 2 patients who visited and hospitalized in Daejon University Oriental Hospital Dept. of Dermatology, with SLE and pemiotic LE from April 2002 till May 2002 Method: We treated them with herb medication, acupuncture and in addition to we consulted western medication if they were needed Results: In case of SLE patient, we considered it to be Yeol-Dok-Chi-Seong, so we priscriped Ga-Mi-So-Dok-Eum1, 2 , Yang-Dok-Baek-ho-Tang first. and till 22 days of hospitalization, we considered to be Gi-Eum-Yang-Heo and priscriped Ji-Hwang-Tang-Hab-Cheong-Sim-Yeon- Ja -Eum-Ga-Mi. but it wasn't adjust and high fever was reaccurred. And till 24 days of hospitalization we priscriped Gal-Geon-Hae-Gi-Tang, and becomed to 25 days, high fever was disappeared and the patient discharged and she has remained generally good condition. In case of Perniotic LE, at first we misdiagnosed her disease as a acral lentiginous melanoma, and we considered it to be Gan-Soo-Yeol-Li-Yeol- Jeung and priscriped Cheong-Pae-Sa-Gan-Tang and transferred her to another hospital, but she was diagnosed Perniotic LE Conclusion: Considering the above results, in case of SLE, in acute phase, we could treat her with oriental-western treatment, and in relief phase, we could treat her with only oriental treatment very efficiently. but in case of perniotic LE, we misdiagnosed it as a acral lentiginous melanoma, but we could experienced very rare perniotic LE case. And also further study is needed on the SLE, and perniotic LE, and we have to systematize of dyagnosis and treatment system.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.112-115
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• 2012

To develop an efficient mass rearing system for Cadra cautella(Walker) and Orius laevigatus(Fieber) were investigated under the conditions of photoperiod 16L : 8D, $70{\pm}5%$ RH and $23{\pm}2^{\circ}C$. The highest efficiency rate(multiply 28.6) of C. cautella was achieved when using the rearing cage of $20{\ell}$ than $3{\ell}$. The highest efficiency rate(multiply 16.3) of O. laevigatus was achieved when using the rearing cage of $5{\ell}$ (adult 1,500, 10 pcs(10 cm) of plant of egg taking). The moth could be successfully reared with all food substrates tested, of which rice bran(43%) + chick feed(43%) + yeast(14%) assumed to be proper for mass-rearing in view of cost.

• Food Engineering Progress
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• v.14 no.3
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• pp.256-262
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• 2010

Saururus chinensis powder was added into cookie dough at 5 levels (0%, 1.5%, 3%, 4.5%, and 6%) by partially replacing equivalent amount of wheat flour in cookie formulation, and cookies thus made were evaluated for physicochemical properties and sensory quality by a small semi-trained panel. Thickness and density of cookies increased significantly with increase in Saururus chinensis powder content (p<0.05); however, those of dough were not affected (p<0.05). The pH of both dough and cookies decreased significantly as the level of Saururus chinensis powder increased (p<0.05). Lightness and yellowness decreased significantly as the Saururus chinensis powder content increased while redness increased significantly (p<0.05). Spread factor decreased with the powder addition (p<0.05). Sensory evaluation indicated that samples with higher amount of the powder received higher scores in terms of taste, flavor, and color but not for hardness (p<0.05). Finally, correlation analysis showed that level of Saururus chinensis powder incorporation was well-correlated with most of the physicochemical properties and sensory attributes studied.

• Korean Journal of Materials Research
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• v.29 no.11
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• pp.697-702
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• 2019

In this study, using a wet chemical process, we evaluate the effectiveness of different solution concentrations in removing layers from a solar cell, which is necessary for recovery of high-purity silicon. A 4-step wet etching process is applied to a 6-inch back surface field(BSF) solar cell. The metal electrode is removed in the first and second steps of the process, and the anti-reflection coating(ARC) is removed in the third step. In the fourth step, high purity silicon is recovered by simultaneously removing the emitter and the BSF layer from the solar cell. It is confirmed by inductively coupled plasma mass spectroscopy(ICP-MS) and secondary ion mass spectroscopy(SIMS) analyses that the effectiveness of layer removal increases with increasing chemical concentrations. The purity of silicon recovered through the process, using the optimal concentration for each process, is analyzed using inductively coupled plasma atomic emission spectroscopy(ICP-AES). In addition, the silicon wafer is recovered through optimum etching conditions for silicon recovery, and the solar cell is remanufactured using this recovered silicon wafer. The efficiency of the remanufactured solar cell is very similar to that of a commercial wafer-based solar cell, and sufficient for use in the PV industry.

• Korean Journal of Materials Research
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• v.29 no.11
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• pp.703-708
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• 2019

In this study, we investigate the relationship between the peeling behavior of the backsheet of a photovoltaic(PV) module and its surface temperature in order facilitate removal of the backsheet from the PV module. At low temperatures, the backsheet does not peel off whereas, at high temperatures, part of the backsheet remains on the surface of the PV module after the peeling process. The backsheet material remaining on the surface of the PV module is confirmed by X-ray diffraction(XRD) analysis to be poly-ethylene(PE). Differential scanning calorimetry(DSC) is also performed to investigate the interfacial characteristics of the layers of the PV module. In particular, DSC provides the melting temperature($T_m$) of laminated ethylene vinyl acetate(EVA) and of the backsheet on the PV module. It is found that the backsheet does not peel off below the $T_m$ of ethylene of EVA, while the PE layer of the backsheet remains on the surface of the PV module above the $T_m$ of the PE. Thus, the backsheet is best removed at a temperature between the $T_m$ of ethylene and that of PE layer.

• Journal of Powder Materials
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• v.29 no.3
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• pp.219-225
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• 2022

An alternative fabrication method for carburizing steel using spark plasma sintering (SPS) is investigated. The sintered carburized sample, which exhibits surface modification effects such as carburizing, sintered Fe, and sintered Fe-0.8 wt.%C alloys, is fabricated using SPS. X-ray diffraction and micro Vickers tests are employed to confirm the phase and properties. Finite element analysis is performed to evaluate the change in hardness and analyze the carbon content and residual stress of the carburized sample. The change in the hardness of the carburized sample has the same tendency to predict hardness. The difference in hardness between the carburized sample and the predicted value is also discussed. The carburized sample exhibits a compressive residual stress at the surface. These results indicate that the carburized sample experiences a surface modification effect without carburization. Field emission scanning electron microscopy is employed to verify the change in phase. A novel fabrication method for altering the carburization is successfully proposed. We expect this fabrication method to solve the problems associated with carburization.

• Journal of Powder Materials
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• v.29 no.5
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• pp.399-410
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• 2022

Changes in the mechanical properties and microstructure of an IN 939 W alloy according to the sintering heating rate were evaluated. IN 939 W alloy samples were fabricated by spark plasma sintering. The phase fraction, number density, and mean radius of the IN 939 W alloy were calculated using a thermodynamic calculation. A universal testing machine and micro-Vickers hardness tester were employed to confirm the mechanical properties of the IN 939 W alloy. X-ray diffraction, optical microscopy, field-emission scanning electron microscopy, Cs-corrected-field emission transmission electron microscopy, and energy dispersive X-ray spectrometry were used to evaluate the microstructure of the alloy. The rapid sintering heating rate resulted in a slightly dispersed γ' phase and chromium oxide. It also suppressed the precipitation of the η phase. These helped to reinforce the mechanical properties.

• Journal of Powder Materials
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• v.29 no.5
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• pp.382-389
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• 2022

A typical trade-off relationship exists between strength and elongation in face-centered cubic metals. Studies have recently been conducted to enhance strength without ductility reduction through surface-treatment-based ultrasonic nanocrystalline surface modification (UNSM), which creates a gradient microstructure in which grains become smaller from the inside to the surface. The transformation-induced plasticity effect in Fe-Mn alloys results in excellent strength and ductility due to their high work-hardening rate. This rate is achieved through strain-induced martensitic transformation when an alloy is plastically deformed. In this study, Fe-6%Mn powders with different sizes were prepared by high-energy ball milling and sintered through spark plasma sintering to produce Fe-6%Mn samples. A gradient microstructure was obtained by stacking the different-sized powders to achieve similar effects as those derived from UNSM. A compressive test was performed to investigate the mechanical properties, including the yielding behavior. The deformed microstructure was observed through electron backscatter diffraction to determine the effects of gradient plastic deformation.

• Journal of the Korean Geotechnical Society
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• v.26 no.10
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• pp.15-25
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• 2010

In this study, a method for estimating the in-situ stress state of NC clays using piezocone penetration test (PCPT) results is proposed. The proposed method is based on a correlation between the PCPT results and strength increment ratio. According to proposed method, no additional testing procedure for collecting undisturbed soil sample is required, which can reduce overall testing cost. To verify this method various analytical solutions were adopted and used. Measured result and predicted result are compared with each other. The verification sites consist of a variety of soil conditions. From the comparison, it is seen that predicted value of effective strcss using the proposed method match well those from measured results.