• 열처리공학회지
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• 제28권1호
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• pp.24-31
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• 2015

In this study, a simulation was used to derive an optimal process of heat treatment with carburizing, and compared the derived result with SCr420HB helical gear in heat treatment with carburized quenching process about a change of the quenching method. The optimal carburizing process time is derived by the simulation with the theoretical time. The process has been performed by oil quenching and salt quenching method. Through the comparison of the results from the simulation(Hardness, effective case depth hardened by carburizing treatment and deformation) and the actual process, analyzed the error value of each quenching. And it verified the applicability of the simulation.

• Design & Manufacturing
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• 제8권2호
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• pp.23-29
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• 2014

Salt bath heat treatment is usually used but recently vacuum heat treatment is increased for the heat treatment of hot work die steels. The differences in two heat treatment processes were compared by testing the mechanical properties of heat treated products. With two different features of processes, mechanical properties such as hardness, tensile strength and impact strength of products show very different results. In this study salt bath heat treated products showed higher tensile strength and impact strength than vacuum heat treated products but hardness was not much different. These lower mechanical properties of vacuum heat treated products are due to differences in heating and quenching process.

• 열처리공학회지
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• 제26권1호
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• pp.7-13
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• 2013

Vacuum heat treatment(indirect heating method) has long exposure time at high temperature and low quenching rate. Contrarily salt bath heat treatment (direct heating method) has short exposure time at high temperature and fast cooling rate. With these different features of processes, mechanical properties such as hardness, tensile strength and impact strength of products show very different results. In this study, Salt bath heat treated products showed higher tensile strength and impact strength than vacuum heat treated products but hardness was not much different. These lower mechanical properties of vacuum heat treated products are due to differences in heat process and secondary hardening with high temperature tempering process. Consequently, It indicates that salt bath heat treatment is better way than vacuum heat treatment for product to have high mechanical properties.

• 열처리공학회지
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• 제21권3호
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• pp.137-143
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• 2008

Effect of quenching medium on the mechanical properties of ductil iron GCD 50 has been investigated using ADI treated specimens. The specimens have been austenitized at $900^{\circ}C$ for 2 hours, followed by controlled cooling to $800^{\circ}C$ under the cooling rate of $0.05^{\circ}C/sec$, then austempered at $380^{\circ}C$, $330^{\circ}C$, $280^{\circ}C$ and $230^{\circ}C$ for 1 hour. The specimens treated in the salt of 5% water were found to have higher tensile strength than that of the normal salt bath. Elongation and impact energy increased in proportion to the increase of retained austenite volume fraction. The increase of cooling rate of the salt by the addition of 5% water to the salt resulted in the increase of retained austenite volume fraction and the formation of fine bainitic ferrite.

• Journal of Applied Biological Chemistry
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• 제48권1호
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• pp.1-6
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• 2005

Analysis of chlorophyll (Chl) fluorescence implicated treatment of 40 mM NaCl decreased maximal photochemical efficiency of photosystem II (PSII) (Fv/Fm), actual quantum yield of PSII (${\Phi}_{PSII}$), and photochemical quenching (qP) in rice, but increased non-photochemical quenching (NPQ). Decreases in Fv/Fm, ${\Phi}_{PSII}$, and qP were significantly alleviated by $30\;{\mu}M$ jasmonic acid (JA), while NPQ increase was enhanced. Transcription levels of antioxidant isoenzyme genes were differentially modulated by NaCl treatment. Expression of cCuZn-SOD2 gene increased, while those of cAPXb, CATb, and CATc genes decreased. JA prevented salt-induced decrease of pCuZn-SOD gene expression, but caused greater decrease in mRNA levels of cAPXa and Chl_tAPX genes. Investigation of vacuolar $Na^+/H^+$ exchanger (NHX2) and 1-pyrroline-5-carboxylate synthetase (P5CS) gene expressions revealed transcription level of NHX2 gene was increased by JA, regardless of NaCl presence, while that of P5CS gene slightly increased only in co-presence of JA and NaCl. Unlike JA, ${\gamma}$-radiation rarely affected expressions of antioxidant isoenzyme, NHX2, and P5CS genes, except for increase in mRNA level of Chl_tAPX and decrease in that of pCuZn-SOD. These results demonstrate enhanced salt-tolerance in JA-treated rice seedlings may be partly due to high transcription levels of pCuZn-SOD, NHX2, and P5CS genes under salt stress.

• 한국토양비료학회지
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• 제43권3호
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• pp.390-399
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• 2010

한발과 염 스트레스에 대한 콩의 저항성 검정에 있어서 Non-photochemical quenching (NPQ)을 적용하기 위하여, 저항성 콩 (신팔달콩 2호)와 대조구 콩 (태광콩)을 이용하여 제한적 관수 (50 m/pot/day) 와 염 (200 mmol NaCl) 처리를 한 후, 엽록소 형광반응의 변수, maximum efficiencies of photosystem II photochemistry ($F_v/F_m$), efficiencies of photosystem II photochemistry (${\Phi}_{PSII}$), NPQ와 $CO_2$ 동화율 ($P_N$) 을 측정하였다. 콩 두 품종의 엽 수분포텐셜은 한발처리에서 -0.2 MPa에서 -0.8 MPa로, 염처리에서는 -0.7 MPa에서 -1.7 MPa로 감소하였다. 염처리에서 엽 수분함량의 감소는 신팔달콩 2호에서 적었다. 두 품종 모두 엽의 수분포텐셜이 감소함에 따라 $F_v/F_m$은 변화가 없었으며, ${\Phi}_{PSII}$와 $P_N$는 감소하였다. NPQ의 경우, 신팔달콩 2호은 한발과 염처리에 모두에서 반응이 나타난 반면, 태광콩에서는 한발처리에서만 나타났다. 두 품종의 모든 처리에서 ${\Phi}_{PSII}$와 $P_N$간에 정의 상관 관계를 보였으나, $P_N$의 감소에 대한 ${\Phi}_{PSII}$의 감소 정도가 신팔달콩 2호에서 적었다. 또한 삼투처리에 따른 ${\Phi}_{PSII}$의 감소와 NPQ의 증가는 신팔달콩 2호에서만 나타나 ${\Phi}_{PSII}$와 NPQ 간의 부의 관계가 유지된 반면, 태광콩에서는 염처리에서 이들간의 연관성이 없었다. 따라서 본 연구는 삼투 저항성의 검정에 있어서 엽록소 형광반응의 단일변수($F_v/F_m$, ${\Phi}_{PSII}$, 및 NPQ)의 이용보다 ${\Phi}_{PSII}$와 NPQ 의 상호관계 분석이 더 유효한 것을 제시하였다.

• Bulletin of the Korean Chemical Society
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• 제12권4호
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• pp.434-437
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• 1991

Irradiation of 5-styryl-1,3-dimethyluracil (5-SDU) with 2,3-dimethyl-2-butene (DMB) gives a [4+2] cycloadduct which is converted into a [2+2] cycloadduct on the prolonged irradiation. Triplet sensitization, quenching, and external heavy atom effect on the [4+2] photocycloaddition reaction demonstrate the singlet pathway and salt effect excludes a radical ion pair precursor possibility. Polar solvents increase the reaction efficiency implying a polar exciplex involvement in the [4+2] photocycloaddition reaction. Inverse temperature dependence both on the reaction and DMB fluorescence quenching of 5-SDU indicates the presence of a singlet exciplex intermediate.

• 통합자연과학논문집
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• 제2권3호
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• pp.215-218
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• 2009

A silaspirotropylidene has been obtained from the reaction of the lithium salt of tetraphenylsilole dianion with 2 equiv of diphenylcyclopropene, followed by quenching with Me3SiCl. Silaspirotropylidene exhibits an unusual optical property its optical property was characterized by UV-vis and fluorescence spectroscopy. Absorption wavelength maxima of silaspirotropylidene was 420 nm. silaspirotropylidene displayed an emission band at 550 nm with excitation wavelength of 420 nm.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.166-167
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• 2013

Bottom ash, which is discharged through a wet process in a thermal power plant, contains much unburned coal due to quenching and much salt due to seawater. However, dry bottom ash discharged through a dry process contains low unburned coal and salt, and has light -weight due to many pores. Therefore, it is expected that it can be used as lightweight aggregate. This study deals with the basic properties of concrete used dry bottom ash as coarse aggregate. As a results, the concrete having high content of dry bottom ash aggregate showed high slump by using water reducing agent and its air content was within 5±1.5% as designed value, similarly to normal weight concrete. It also showed a lower compressive strength than 100% of crushed stone.

• Bulletin of the Korean Chemical Society
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• 제17권4호
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• pp.358-362
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• 1996

The ionic strength dependent binding mode of 9-aminoacridine (9AA), a well-known DNA intercalator, to DNA is studied by flow linear dichroism, circular dichroism, fluorescence techniques and equilibrium dialysis. The DNA-bound 9AA exhibits spectral properties corresponding to the intercalative binding mode disregarding the salt concentrations; the angle between the long-axis transition moment of the 9AA molecule and DNA helix axis is calculated to be about 65°, indicating a significant deviation from the classical intercalation. At low salt concentrations, however, upwards bending curve in Stern-Volmer plot is observed (where 9AA is a fluorophore and DNA a quencher), indicating the coexistence of both static and dynamic quenching mechanisms or the existence of an additional binding site.