• Journal of Korean Society of Forest Science
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• v.98 no.6
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• pp.748-756
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• 2009

The key for cultivating Lentinula edodes in sawdust bags with an appropriate strain and medium is to encourage the mushroom growth, while discouraging contaminating fungi by controlling environment, especially temperature and relative humidity (RH). To investigate the daily and seasonal fluctuation of temperature and RH in two L. edodes cultivation sheds types, HOBO data loggers was set and the collected data were analyzed. In a Taiwan type L. edodes cultivation shed, temperature and humidity changes were divided into five characteristic periods: mycelium growing winter, mushroom fruiting spring, mushroom fruiting early summer, mushroom nonfruiting summer and mushroom fruiting autumn. First, the mycelium growing winter was December to early March with daily mean temperature of $-1{\sim}8^{\circ}C$. Second, mushroom fruiting spring was mid March to late May with daily mean temperature of $8{\sim}21^{\circ}C$ and day-night temperature difference of $15^{\circ}C$. Third, the Mushroom fruiting early summer was early June to early July with 17 to $25^{\circ}C$. Fourth, nonfruiting summer was mid July to mid August with daily mean temperature of $25{\sim}28^{\circ}C$. Lastly, mushroom fruiting autumn was late August to October with daily mean temperature of $10{\sim}23^{\circ}C$ and with cyclic temperature change by $7^{\circ}C$ decrease and 5 increase every 5 to 7 days. In a Chinese type shed, temperature ranged $-1.9{\sim}5.0^{\circ}C$ during winter and $15{\sim}32^{\circ}C$ during June to October. Temperature and relative humidity changed $12{\sim}30^{\circ}C$ and 40~100%, respectively, depending on 0~150 cm shelf heights of by positions in the shed. In conclusion, to grow L. edodes but to discourage contaminating fungi, that is, not to be too high in temperature and RH, the growers changed temperature and RH by adjusting shading, aeration and insulation in the shed.

• Composites Research
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• v.19 no.5
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• pp.20-27
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• 2006

Self-sensing and interfacial evaluation of Ni nanowire/polymer composites were investigated using electro-macromechanical technique, which can be used fur a feasible sensing measurement on tensile and compressive loading/consequent unloading, temperature, and humidity. Mechanical properties of Ni nanowire with different aspect ratio and adding contents in either epoxy or silicone composites were measured indirectly using electro-pullout test under uniform and non-uniform cyclic loadings. Comparing apparent modulus with the conventional mechanical tensile modulus of Ni nanowire/epoxy composites, the trends were consistent with each other. Ni nanowire/epoxy composites showed the sensing response on humidity and temperature. Self-sensing on applied tensile and compressive loading/unloading was also responded for Ni nanowire/silicone composites via electrical contact resistivity showing the opposite trend between tension and compression. It can be due to the different electrically-interconnecting mechanisms of dispersed Ni nanowires embedded in silicone matrix.

• Corrosion Science and Technology
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• v.7 no.6
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• pp.315-318
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• 2008

The atmospheric corrosion performance of Al-alloying, Si-alloying and Al-Si-alloying steel were studied by wet/dry cyclic corrosion tests (CCT) at $30^{\circ}C$ and 60% relative humidity (RH). The corrosion electrolyte used for CCT was 0.052 wt% $NaHSO_{3}$ (pH~4) solution. The result of gravimetry demonstrated that Al-Si-bearing steels showed lower corrosion resistance than other rusted steels. But the rusted 0.7%Si-alloying steel showed a better corrosion resistance than rusted mild steel. Polarization curves demonstrated that Al-/Si-alloying and Al-Si-alloying improved the rest potential of steel at the initial stage; and accelerated the cathodic reduction and anodic dissolution after a rust layer formed on the surfaces of steels. XRD results showed that Al-Si-alloying decreased the volume fraction of $Fe_{3}O_{4}$ and $\alpha-FeOOH$. The recycle of acid accelerated the corrosion of steel at the initial stage. After the rust layer formed on the steel, the leak of rust destabilized the rust layer due to the dissolution of compound containing Al (such as $FeAl_{2}O_{4}$, $(Fe,\;Si)_{2}(Fe,\;Al)O_{4}$). Al-Si-alloying is hence not suitable for improving the anti-corrosion resistance of steel in industrial atmosphere.

• Elastomers and Composites
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• v.55 no.1
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• pp.51-58
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• 2020

In this study, the thermal oxidation of raw natural rubber (NR) was investigated under controlled conditions by optical image and fourier transform infrared (FT-IR) analysis. The thermal oxidation was performed on a transparent thin film of raw NR coated on a KBr window in a dark chamber at 80℃ under low humidity conditions to completely exclude moisture and restrict light oxidation. Images of the thin film of raw NR were obtained before and after thermal oxidation. FT-IR absorption spectra were measured in the transmission mode at different thermal exposure times. The thermal oxidation of NR was examined by the changes in the absorption peaks at 3449, 1736, 1447, 1377, 1242, 1072, and 833 cm^-1, which corresponded to a hydroxyl group (-OH), a carbonyl group (-C=O) from an aldehyde and a ketone, a methylene group (-CH₂-), a methyl group (-CH₃), a carbon-oxygen single bond (-C-O) from an epoxide, a carbon-oxygen bond (-C-O) from an ether, an alcohol, a peroxide, or a cyclic peroxide, and a cis-methine group (cis-CCH₃=CH-), respectively. In the initial stage of thermal oxidation, two different types of free radicals were produced quickly and randomly by the homolytic cleavage of a double bond and allylic hydrogen abstraction. Aldehydes and ketones were formed from chain scissions of the double bonds and alcohols were produced from allylic hydrogen abstraction at the methylene or methyl groups. Two reactions seemed to proceed competitively with each other. At a later stage, oxidative crosslinks seemed to dominate through the combination of free radicals such as an allyl radical (CH=CHCH₂·), alkoxy radical (RO·), and peroxy radical (ROO·) and the reaction of a hydroperoxide (-ROOH) with a double bond. The image obtained after thermal oxidation showed hardening without cracks. Based on these observations, a plausible two-step mechanism was suggested for chain hardening caused by the thermal oxidation.