• 센서학회지
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• 제31권6호
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• pp.428-432
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• 2022

In this study, we describe the improvement of the resolution of a paper-based sensor by fabricating a high-concentration ninhydrin part using a low-temperature drying method to detect proline with high resolution. In the conventional paper-based sensor for detecting proline, the ninhydrin part is fabricated at room temperature, and in this process, the ninhydrin solution spreads around the ninhydrin part. Therefore, the concentration of the ninhydrin part becomes lower than that of the applied solution, lowering the resolution of the sensor. The proposed paper-based sensor better improved the sensitivity of the sensor compared to the existing sensor by fabricating a high-concentration ninhydrin part through drying the ninhydrin solution using a low-temperature drying method. Owing to the experiment, the intensity of the green color of the paper-based sensor with the integrated ninhydrin part fabricated at 10 ℃ is approximately 20% lower than the paper-based sensor with an integrated ninhydrin part fabricated at room temperature, indicating better sensor resolution. Therefore, the paper-based sensor with an integrated ninhydrin part fabricated at a high concentration could be useful for diagnosing drought.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 추계학술대회 논문집
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• pp.80-84
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• 1993

In this research, we studied the variation of the dielectric loss absorption of the dielectric loss absorption of the sample according with the change to $\^$60/Co-${\gamma}$-ray irradiation dose of the influence of temperature and applied voltage. In order to investigate the effect of irradiation oriented polypropylene film, we have observed dissipation factor within the temperature range of 30∼130 [$^{\circ}C$] and voltage range of 100∼250$^{\circ}C$ [V]. As for the dependency of temperature by dissipation factor, the ${\alpha}$-peak which appears at high temperature increases accordingly to the increasement of irradiation dose which is contributed by the crystal region and moves towards the high temperature. The ${\beta}$-peak which appears at low temperature is origined from dipoles and molecular motions in the amorphous region. As for the dependency of voltage by tan$\delta$, at low temperature the peak of the tan$\delta$, at low temperature the peak of the tan$\delta$ shifts accordingly to the increasement of irradiation dose towards the high temperature region.

• Asian-Australasian Journal of Animal Sciences
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• 제13권5호
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• pp.625-629
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• 2000

Six yearling Suffolk ewes were used to study the effect of different roughage proportion diets (30%=LR, and 70%=HR) and intake levels (0.7 M and 1.3 M) on heat production and thermoregulatory responses in sheep exposed to different ambient temperatures (20 and $30^{\circ}C$). Sheep fed HR had higher heat production (HP) and time spent eating (TSE) and lower time spent standing (TSS) than those fed LR. But effect of roughage proportion on vaginal temperature (Tv) was obvious only at high intake and at $30^{\circ}C$. Sheep fed high intake had higher Tv, HP, TSS, and TSE than those fed low intake. Roughage proportion and intake level did not have an effect on respiration rate (RR), but ambient temperature did. Ambient temperature did not have an effect on HP, TSS and TSE. At $30^{\circ}C$ sheep had higher Tv and RR than those at $20^{\circ}C$. There were interactions between intake level and ambient temperature in TSS, between intake level and roughage proportion in TSE, and between roughage proportion and ambient temperature in HP. Results indicate that high roughage diet imposes a greater potential heat load on animals than low roughage diet when given at high ambient temperature, but not at low ambient temperature. And the effects is more pronounced at high intake.

• 한국재료학회지
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• 제27권2호
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• pp.69-75
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• 2017

To establish low-temperature process conditions, process-property correlation has been investigated for Ga-doped ZnO (GZO) thin films deposited by pulsed DC magnetron sputtering. Thickness of GZO films and deposition temperature were varied from 50 to 500 nm and from room temperature to $250^{\circ}C$, respectively. Electrical properties of the GZO films initially improved with increase of temperature to $150^{\circ}C$, but deteriorated subsequently with further increase of the temperature. At lower temperatures, the electrical properties improved with increasing thickness; however, at higher temperatures, increasing thickness resulted in deteriorated electrical properties. Such changes in electrical properties were correlated to the microstructural evolution, which is dependent on the deposition temperature and the film thickness. While the GZO films had c-axis preferred orientation due to preferred nucleation, structural disordering with increasing deposition temperature and film thickness promoted grain growth with a-axis orientation. Consequently, it was possible to obtain a good electrical property at relatively low deposition temperature with small thickness.

• Progress in Superconductivity
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• 제12권1호
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• pp.41-45
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• 2010

Low temperature micro-calorimeters have been employed in the field of high resolution alpha spectrometers. These alpha detectors typically consist of a superconducting or metal absorber and a temperature sensor. The temperature sensor can be a transition edge sensor (TES), a metallic magnetic calorimeter (MMC) or other low temperature detectors for an accurate measurement of temperature change due to an alpha particle absorption. We report a recent study of the heat flow between a replaceable absorber and a temperature sensor. A piece of gold foil in $2.4{\times}2.7{\times}0.03\;mm^3$ is used as an absorber. A $40\;{\mu}m$ diameter Au:Er paramagnetic sensor is attached to another small piece of gold foil in $400{\times}200{\times}30\;{\mu}m^3$ to serve as the temperature sensor. This sensor assembly, Au:Er and gold foil, is placed on a miniature SQUID susceptometer in a gradiometric configuration. The thermal connection between the absorber and the sensor was made with three gold bonding wires. The measured thermal conductance shows a linear dependence to the temperature. The values are in a good agreement with Wiedemann-Franz type thermal conductance of the gold wires.

• 한국물환경학회지
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• 제22권2호
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• pp.258-263
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• 2006

ANAMMOX (Anaerobic ammonium oxidation) reactor, which was cultivated ANAMMOX bacteria in mesophilic condition ($35^{\circ}C$), was operated to investigate the effects of temperature. In $20{\sim}30^{\circ}C$ of operation condition, which was assumed as field-temperature, total N removal and $NH_4-N$ removal rate were declined from about 2.50 and $1.27kg\;N/{m^3}_{reactor}-day$ (0.06 and 0.03 kg N/kgVSS/day) to 1.62 and $0.41kg\;N/{m^3}_{reactor}-day$ (0.04 and 0.01 kg N/kgVSS/day), In this range of temperature, ANAMMOX had very low activities but acid fermentation bacteria and denitrifiers, which were competitors of substrates, had high activities relatively. Though operation temperature was higher than inhibition condition for two months, ANAMMOX activities could not been recovered once they were inhibited by low temperature. This fact was resulted from very slow doubling time of ANAMMOX bacteria. This study shows that maintenance device of optimal temperature is necessary required in field application of ANAMMOX.

• 한국식생활문화학회지
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• 제33권3호
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• pp.276-282
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• 2018

This study examined the effects of low temperature conditions on the expansion of choux when mixing the dough with egg fluid. The egg fluid was tested at 5 and $17^{\circ}C$, and the dough temperature was 20, 30, 40, 50, 60 or $70^{\circ}C$. The expansion decreased with decreasing temperature of the egg fluid and dough, with the concomitant formation of membranes in the cavities of choux because of the poor emulsion stability of the choux paste. In addition, the structure of the choux pastry was not dense and the cracks in the surface were partial and narrow. The shape, expansion and cracks of choux were the best at a dough temperature of 60 and $70^{\circ}C$ added with egg fluid at $17^{\circ}C$. The temperature of the choux paste in these two samples was higher than the melting point of the butter used to produce the paste. Therefore, the practical limit temperature when mixing the egg fluid and dough is 20 and $60^{\circ}C$, respectively, and care should ve taken to maintain a low temperature when making choux in confectionary.

• 한국재료학회지
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• 제25권8호
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• pp.417-422
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• 2015

In this study, low-carbon hypoeutectoid steels with different ferrite-pearlite microstructures were fabricated by varying transformation temperature. The microstructural factors such as pearlite fraction and interlamellar spacing, and cementite thickness were quantitatively measured and then Charpy impact tests conducted on the specimens in order to investigate the correlation of the microstructural factors with impact toughness and ductile-brittle transition temperature. The microstructural analysis results showed that the pearlite interlamellar spacing and cementite thickness decreases while the pearlite fraction increases as the transformation temperature decreases. Although the specimens with higher pearlite fractions have low absorbed energy, on the other hand, the absorbed energy is higher in room temperature than in low temperature. The upper-shelf energy slightly increases with decreasing the pearlite interlamellar spacing. However, the ductile-brittle transition temperature is hardly affected by the pearlite interlamellar spacing because there is an optimum interlamellar spacing dependent on lamellar ferrite and cementite thickness and because the increase in pearlite fraction and the decrease in interlamellar spacing with decreasing transformation temperature have a contradictory role on absorbed energy.

• 자원환경지질
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• 제34권1호
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• pp.147-156
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• 2001

티탄자철석(titanomagnetite)은 해양지각을 이루는 현무암에 존재하는 중요한 자성광물로서 일반적으로 저온산화에 의해 양이온이 결핍된(cation-deficient) 티탄맥히마이트(titanomaghemite)로 변한다. 실험실에서 철성분 제거방식(removal of iron mechanism)을 통해 자연에서 일어나는 티탄자철석의 수성 저온산화(low-temperature aqueous oxidation)를 재현하였으며, 산화정도에 따라 티탄맥히마이트의 자기적 특성이 민감하게 변화하는 것을 관찰하였다. 본 실험 결과 산화정도에 따라 티탄자철석의 큐리온도(Tc)는 166$^{\circ}C$에서 40$0^{\circ}C$로 증가하였고, 상온에서의 포화자화 강도(Ms)는 126.30 kA/m(25.26 emu/g)에서 16.55 kA/m(3.31 emu/g)로 감소하였으며, 항자기력(Hc)은 6.13 kA/m(77 Oe)에서 38.83 kA/m (488 Oe)로 잔류항자기력(Hcr)은 23.24 kA/m(292 Oe)에서 47.03 kA/m(591 Oe)로 증가함을 관찰하였다. 또한 대자율($\chi$)은 $2023{\times}10^{-6}SI$에서 $84{\times}10^{-6}SI$로 감소함을 나타내었다. 이와 같은 결과를 근거로 현재에서 30 Ma까지의 해양지각의 자화 강도의 변화는 티탄자철석의 저온산화에 의한 결과로 해석하였으며 30~120 Ma에 이르는 해양지각의 자화 강도의 변화는 해양지각에 포함된 티탄자철석의 산화와 산화에 순반되는 광물전에 의한 결과로 추정하였으며 보다 구체적인 원인은 해양지각에서 채취한 시료에 대한 체계적인 연구를 통해서 밝혀질 것으로 기대된다.

• Computers and Concrete
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• 제33권5호
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• pp.605-619
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• 2024

The increase of reclaimed asphalt pavement (RAP) content in recycled asphalt concrete (RAC) is accompanied by the degradation of low-temperature cracking resistance, which has become an obstacle to the development of RAC. This paper aims to reveal the meso-scale mechanisms of the low-temperature fracture behavior of RAC and provide a theoretical basis for the economical recycling of RAP. For this purpose, micromechanical heterogeneous peridynamic model of RAC was established and validated by comparing three-point bending (TPB) test results against corresponding numerical simulation results of RAC with 50% RAP content. Furthermore, the models with different aggregate shapes (i.e., average aggregates circularity (${\bar{C_r}}=1.00$, 0.75, and 0.50) and RAP content (i.e., 0%, 15%, 30%, 50%, 75%, and 100%) were constructed to investigate the effect of aggregate shape and RAP content on the low-temperature cracking resistance. The results show that peridynamic models can accurately simulate the low-temperature fracture behavior of RAC, with only 2.9% and 13.9% differences from the TPB test in flexural strength and failure strain, respectively. On the meso-scale, the damage in the RAC is mainly controlled by horizontal tensile stress and the stress concentration appears in the interface transition zone (ITZ). Aggregate shape has a significant effect on the low-temperature fracture resistance, i.e., higher aggregate circularity leads to better low-temperature performance. The large number of microcracks generated during the damage evolution process for the peridynamic model with circular aggregates contributes to slowing down the fracture, whereas the severe stress concentration at the corners leads to the fracture of the aggregates with low circularity under lower stress levels. The effect of RAP content below 30% or above 50% is not significant, but a substantial reduction (16.9% in flexural strength and 16.4% in failure strain) is observed between the RAP content of 30% and 50%. This reduction is mainly attributed to the fact that the damage in the ITZ region transfers significantly to the aggregates, especially the RAP aggregates, when the RAP content ranges from 30% to 50%.