• Journal of the Korean Society for Heat Treatment
• /
• v.22 no.6
• /
• pp.368-374
• /
• 2009

Nickel titanium shape memory alloys (NiTi) have been investigated for applications in the biomedical industry. However, little is known about the influences of surface modifications on the propertise of these alloys. The effect of electropolishing and heat treatments was found to exhibit significant surface roughness. Change of phase was B2, r-phase and B19' by heat treatments. In this study, effect of the electropolishing conditions on surface roughness is investigated in Ni-Ti alloys (Nitinol). Variation in phases with heat treatment temperature is investigated for a Ni-Ti alloy by X-ray diffraction and DSC. Characteristic of the microstructure have been observed by SEM. Surface roughness have been measured by AFM. The results clearly show that significant different in surface property to heat treated at $500^{\circ}C$ (R-phase). $TiO_2$ phases preciritated all of the specimens. It is not good effect of surface roughness because made to surface relief. The surface roughness appears to be important in the property of Ni-Ti alloys for biomedical applications.

• Journal of Power System Engineering
• /
• v.18 no.2
• /
• pp.37-42
• /
• 2014

The purpose of this paper is to investigate polarization characteristics of heat-treated Ni-based self-flux alloy coating in alkaline solution. Ni-based self-flux alloy powder was sprayed to a steel substrate using flame spray process, and heat treatments were performed in a vacuum furnace at $800^{\circ}C$, $900^{\circ}C$, $1000^{\circ}C$ and $1100^{\circ}C$. After heat treatments, corrosion tests were carried out using potentiostat/galvanostat at solution with pH 8 and pH 13. Corrosion potential(Ecorr) and corrosion current density(Icorr) could be analyzed from polarization curve. Anticorrosive effect of heat-treated coating at solution with pH 8 was relatively greater than at solution with pH 13. Heat-treated coating at $1100^{\circ}C$ showed the greatest anti-corrosion characteristics in alkaline solution.

• Preventive Nutrition and Food Science
• /
• v.12 no.4
• /
• pp.251-258
• /
• 2007

Thermal resistance and heat activation characteristics of Clostridium botulinum ATCC 25763 spores were evaluated. The effects of nisin and pH on the activation and subsequent germination were also investigated. Spores of C. botulinum were not inactivated by heat treatments up to $92^{\circ}C$ for 2 hr. Heat treatment at $85^{\circ}C$ for 90 min was selected as the optimal activation condition based on monitoring subsequent germination. L-alanine alone or in combination with L-cysteine was not sufficient to germinate the spores of this strain. Tryptone-Peptone- Glucose-Yeast extract (TPGY) broth supplemented with L-alanine was used as a suitable germination medium. Decreasing pH of activation suspension increased the degree of phase darkening, i.e., germination. In addition, the presence of nisin during activation increased the degree of phase darkening. The majority of spore populations were dormant at a pH of less than 2.8, and these populations required heat activation to increase the culturability on TPGY agar medium. However, extended heating in the presence of nisin at pH 2.8 decreased the spore count; however, heat activation was less necessary at pH 3.4, compared at pH 2.8.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2004.11a
• /
• pp.69-79
• /
• 2004

A feeding trial was conducted to determine whether dietary vitamin C (200 mg/kg) and vitamin E (250 mg/kg) prevent any drops in egg shell quality under heat stress in broiler breeder hens. One hundred and sixty molted Ross broiler breeders were housed randomly in an individual cage at 83 weeks of age. Four dietary treatments with forty hens and four replications per treatment were control (no additional vitamins). vitamin C-. or vitamin E-supplemented. and combined supplementation of the two vitamins. After a ten-day-adaptation period at 25 $^{\circ}C$. the ambient temperature was kept at 32 $^{\circ}C$ for a three-week-testing period. Egg production dropped dramatically over week but it did not show a significant change among treatments (P<0.05). However. egg weight. SG. shell thickness. SWUSA. puncture force and shell breaking strength of the birds fed the diet with the combined vitamins C and E were significantly improved than those fed the basal diet during the heat stress period (P<0.05). The hens fed the vitamin C supplemented diet showed a tibia breaking strength of 37.16 kg statistically higher than those of the basal and the vitamin E supplemented groups (P<0.05). The hens fed the basal diet showed higher serum corticosterone levels. a mean of 5.97 ng/ml. than those of the rest of treatments (P<0.05). The heat stress elevated heterophils but decreased lymphocytes in serum. and it changed H/L ratios of all the treatments. The increases in H/L ratios were alleviated in the bird by feeding vitamin C and/or vitamin E supplemented diets. but they did not differ significantly (P<0.05). In conclusion. vitamins C (200 mg/kg) and/or E (250 mg/kg) supplementation to diets could prevent drops in egg shell quality and tibia bone strength by alleviating stressful effects from high temperature in broiler breeder hens.

• Journal of the East Asian Society of Dietary Life
• /
• v.23 no.5
• /
• pp.620-628
• /
• 2013

In this study, the condition for preventing abnormal fermentation was set by heating the nuruk extract, such that glycosyl enzymes maintain its activity and unnecessary microbes are removed. The total colony of microbes in the heated nuruk extract was highest in number at $25^{\circ}C$ and began to reduce at 50, $60^{\circ}C$ and sharply reduced over $70^{\circ}C$. Saccharogenic power (SP), glucoamylase and acidic protease activities were highest at $50^{\circ}C$, 10, 20, 30min and ${\alpha}$-amylase activity was lower at $50^{\circ}C$ than at $25^{\circ}C$. In the pHs of the nuruk extract, as the heat temperature became higher and treatment time was longer, the pHs were reduced significantly. The total acidities of heat treatments at 50, $60^{\circ}C$ were lower by 0.2% than at $25^{\circ}C$, where as the 70, $80^{\circ}C$ treatments showed a sharp rise from the early stage of fermentation. Soluble solids showed the same aspects with the glycosyl enzymes cases. In reducing sugar, 25, $50^{\circ}C$ treatments were sharply increased from the first day of fermentation while $60^{\circ}C$ treatments began to rise from second day 70, $80^{\circ}C$ were slightly increased after the fourth day. The normally alcohol fermented treatments were 25, 50 and $60^{\circ}C$ 30min. The $70^{\circ}C$ treatments almost did not alcohol fermentation. In the preference tests, taste and total acceptability were high at 25, $50^{\circ}C$ treatments. These results suggest that makgeolli using heat treated nuruk extract also has good taste as well as did not.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
• /
• v.33 no.2
• /
• pp.140-155
• /
• 2020

Objectives : The purpose of this study is to report the effectiveness of korean medical treatments on recurrent aphthous stomatitis(RAS) diagnosed as excess pattern(實證) based on symptoms of damum(痰飮), blood stasis(瘀血) and fire-heat(火熱). Methods : We treated a 61-year-old male patient who has RAS by korean medicine, pharmacopuncture and acupuncture treatment. These treatments were performed from 2020.01.22. to 2020.02.29. We have confirmed the improvement of ulcer lesions and pain. We recorded images that include change of symptoms. Results : After the treatments were done, the scores of numeric rating scale(NRS), oral health impact profile-14 (OHIP-14), oral assessment guide (OAG) and world health organization oral toxicity scale (WHO OTS) were decreased. The NRS score was decreased from 7 to 1. The OHIP-14 score was decreased from 30 to 14. The OAG score was decreased from 17 to 9. The WHO OTS score was decreased from 2 to 1. And ulcer lesions were clearly decreased. Conclusions : According to the result, korean medical treatments such as korean medicine, pharmacopuncture and acupuncture treatment, that are targeted at excess pattern(實證) caused by damum(痰飮), blood stasis(瘀血) and fire-heat(火熱) can be effective for the treatment of RAS.

• Journal of Korea Foundry Society
• /
• v.28 no.5
• /
• pp.221-225
• /
• 2008

The structural and hardness variations of Mg-5Sn-(1,2,3) Ca (wt%) alloys have been investigated during various aging heat treatments followed by solution heat treatment at $500^{\circ}C$ for 24 hrs. Maximum hardness of Hv61 has been obtained for Mg-5Sn-3Ca alloys, when the aging treatment was performed at $200^{\circ}C$ for 24 hrs. The microstructures were critically changed when the content of Ca was more than 1wt%, since CaMgSn and $Mg_{2}Ca$ phases were mainly precipitated during aging treatments. The hardness variations with structural evolutions are discussed with respect to the aging temperatures and times.

• The Journal of Advanced Prosthodontics
• /
• v.8 no.2
• /
• pp.75-84
• /
• 2016

PURPOSE. To evaluate the effect of various surface treatments on the surface structure and shear bond strength (SBS) of different ceramics. MATERIALS AND METHODS. 288 specimens (lithium-disilicate, leucite-reinforced, and glass infiltrated zirconia) were first divided into two groups according to the resin cement used, and were later divided into four groups according to the given surface treatments: G1 (hydrofluoric acid (HF)+silane), G2 (silane alone-no heat-treatment), G3 (silane alone-then dried with $60^{\circ}C$ heat-treatment), and G4 (silane alonethen dried with $100^{\circ}C$ heat-treatment). Two different adhesive luting systems were applied onto the ceramic discs in all groups. SBS (in MPa) was calculated from the failure load per bonded area (in $N/mm^2$). Subsequently, one specimen from each group was prepared for SEM evaluation of the separated-resin-ceramic interface. RESULTS. SBS values of G1 were significantly higher than those of the other groups in the lithium disilicate ceramic and leucite reinforced ceramic, and the SBS values of G4 and G1 were significantly higher than those of G2 and G3 in glass infiltrated zirconia. The three-way ANOVA revealed that the SBS values were significantly affected by the type of resin cement (P<.001). FIN ceramics had the highest rate of cohesive failure on the ceramic surfaces than other ceramic groups. AFM images showed that the surface treatment groups exhibited similar topographies, except the group treated with HF. CONCLUSION. The heat treatment was not sufficient to achieve high SBS values as compared with HF acid etching. The surface topography of ceramics was affected by surface treatments.

• Fisheries and Aquatic Sciences
• /
• v.17 no.2
• /
• pp.203-207
• /
• 2014

The present study was conducted to elucidate effects of heat, salt and hydrocolloid treatments on flying fish Cypselurus agoo roe analogs prepared using calcium alginate gel. The changes in size, sphericity and rupture strength of the analogs as affected by treatments of heat, sodium chloride and hydrocolloids were investigated. The size (mm), sphericity (%), and rupture strength (kPa) of the analogs were $2.2{\pm}0.1$, $98.2{\pm}0.2$, and $74.7{\pm}1.7$, respectively. When the analogs were heated at $95^{\circ}C$ in water, the size was slightly decreased. The rupture strength by curing with 2% sodium chloride was slightly increased. Sphericity didn't show significant differences by sodium chloride and heat treatment. The rupture strength of the analogs was slightly decreased by heat treatment, whereas remarkably decreased by curing with sodium chloride. In order to prevent a remarkable decrease in rupture strength of the analogs by curing with sodium chloride, the analogs were treated with hydrocolloids such as xanthan gum, gum guar, glucomannan, pectin and gelatin. The hydrocolloids treated analogs showed an increment in size and no significant changes in sphericity. On the other hand, the rupture strength of the hydrocolloids treated analogs exhibited remarkable increase than that of untreated ones.

• Journal of the Korean Society for Precision Engineering
• /
• v.5 no.4
• /
• pp.48-58
• /
• 1988

This study was undertaken to observe the formation behavior of ferro- magnetic phase in Mn-Al-Cu Alloys. The alloy selected for this investigation was 70% Mn-29% Al-1% Cu. This pre-allyed pig was prepared to the cylinderical castings using an Induction furnace after homogenizing at $1100^{\circ}C$ for 2hr, the specimens were cooled by cooling methods. Subwequent isothermal heat treatments were followed at $550^{\circ}C$ for various periods of time at predetermined(1-1000min). The formation behavior of ferromagnetic phase was investigated by measurements of magnetic properties of the specimens at each stage of heat treatment, and optical microscopic esamination and X-Ray diffraction analyses were also employed. By this basic experimental results, the conclusions are as follows 1) In order to obtain much amount of ferromagnetic phase, the optimum average cooling rate was about 7.35-$16.4^{\circ}C$/sec($1100^{\circ}C$-$600^{\circ}C$). 2) We verified the decomposition of {\tau} phase to {\beta} -Mn and {\gamma} , as the specimens were homogenized at $1100^{\circ}C$ for 12hr, then heat-treased at $550^{\circ}C$ for 1-1000min. 3) A condition of optimum heat treatments in Mn-Al-Cu permanent mag-netic alloys showed that after homogenizing at $1100^{\circ}C$ for 2hr, the speciments were cooled in air or furnace(A) and subsequent heat treatments at $550^{\circ}C$ for 1-30min. The maximum magnetic properties were measured as follows: Air cooling; Br=1200(Gause), bHc=100(oe), (BH)max=0.07(MGOe) Furnace cooling(A);Br=950(Gauss), bhe=80(Oe), (BH)max=0.05(MGOe)