• Title/Summary/Keyword: Mechanical activation

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Kinetic Data for Texture Changes of Foods During Thermal Processing

  • Lee, Seung Hwan
    • Food Engineering Progress
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    • v.21 no.4
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    • pp.303-311
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    • 2017
  • To automate cooking processes, quantitative descriptions are needed on how quality parameters, such as texture change during heating. Understanding mechanical property changes in foods during thermal treatment due to changes in chemical composition or physical structure is important in the context of engineering models and in precise control of quality in general. Texture degradation of food materials has been studied widely and softening kinetic parameters have been reported in many studies. For a better understanding of kinetic parameters, applied kinetic models were investigated, then rate constants at $100^{\circ}C$ and activation energy from previous kinetic studies were compared. The food materials are hardly classified into similar softening kinetics. The range of parameters is wide regardless of food types due to the complexity of food material, different testing methods, sample size, and geometry. Kinetic parameters are essential for optimal process design. For broad and reliable applications, kinetic parameters should be generated by a more consistent manner so that those of foods could be compared or grouped.

Update on dentin hypersensitivity: with the focus on hydrodynamic theory and mechanosensitive ion channels

  • Won, Jonghwa;Oh, Seog Bae
    • International Journal of Oral Biology
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    • v.44 no.3
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    • pp.71-76
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    • 2019
  • Dentin hypersensitivity is an abrupt intense pain caused by innocuous stimuli to exposed dentinal tubules. Mechanosensitive ion channels have been assessed in dental primary afferent neurons and odontoblasts to explain dentin hypersensitivity. Dentinal fluid dynamics evoked by various stimuli to exposed dentin cause mechanical stress to the structures underlying dentin. This review briefly discusses three hypotheses regarding dentin hypersensitivity and introduces recent findings on mechanosensitive ion channels expressed in the dental sensory system and discusses how the activation of these ion channels is involved in dentin hypersensitivity.

A Study on the Economic Effect of the Establishment of Convergence Zone in the Gyeongbuk Industry-University Convergence Area (경북산학융합지구 융복합 Zone 조성 경제적 파급효과 연구)

  • Kim, Shin-Pyo;Kim, Jae-Moon;Gown, Yun-Ha;OH, Se-Dong;Lee, Soon-Bea
    • Journal of Industrial Convergence
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    • v.13 no.1
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    • pp.1-9
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    • 2015
  • The purpose of this Study is to analyze the economic effect of the project for the establishment of the Convergence Zone of the Gyeongbuk Industry-University Convergence Area aimed at activation of R&D of companies within the Kumoh Technology Valley. As the result of the analysis, the investment of 56.837 Billion Won in the establishment of the Convergence Zone of the Gyeongbuk Industry-University Convergence Area had the effect on production inducement valued at 133.582 Billion Won, effect on added value inducement valued at 41.764 Billion Won, effect on import inducement valued at 16.794 Billion Won and the effect on employment inducement numbered at 4,992 persons.try.

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Neural Network Model Compression Algorithms for Image Classification in Embedded Systems (임베디드 시스템에서의 객체 분류를 위한 인공 신경망 경량화 연구)

  • Shin, Heejung;Oh, Hyondong
    • The Journal of Korea Robotics Society
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    • v.17 no.2
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    • pp.133-141
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    • 2022
  • This paper introduces model compression algorithms which make a deep neural network smaller and faster for embedded systems. The model compression algorithms can be largely categorized into pruning, quantization and knowledge distillation. In this study, gradual pruning, quantization aware training, and knowledge distillation which learns the activation boundary in the hidden layer of the teacher neural network are integrated. As a large deep neural network is compressed and accelerated by these algorithms, embedded computing boards can run the deep neural network much faster with less memory usage while preserving the reasonable accuracy. To evaluate the performance of the compressed neural networks, we evaluate the size, latency and accuracy of the deep neural network, DenseNet201, for image classification with CIFAR-10 dataset on the NVIDIA Jetson Xavier.

Effects of Taurine and ${\beta}-Alanine$ on the Responses of Dorsal Horn Cell to Various Stimuli in Cats (Taurine 및 ${\beta}-alanine$이 고양이 척수후각세포의 Activity에 미치는 효과)

  • Koh, Young-Ik;Kang, Sok-Han;Kim, Jin-Hyuk;Shin, Hong-Kee;Kim, Kee-Soon
    • The Korean Journal of Physiology
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    • v.24 no.1
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    • pp.171-180
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    • 1990
  • In 19 cats anesthetized with ${\alpha}-chloralose$ effects of taurine and ${\beta}-alanine$ on the responses of wide dynamic range (WDR) cells to mechanical, chemical and thermal stimuli were investigated in the lumbar spinal cord of the cat. Also studied was an interaction of strychnine with taurine in affecting the activities of WDR cells. Following intravenous administration of taurine, the responses of WDR cells to all types of mechanical stimuli were markedly enhanced, demonstrating that the response to pressure was most sensitive to taurine action. When the receptive field was exposed to thermal stimuli ($50^{\circ}C$) for 20 sec. taurine increased activity of WDR cell to 169.5% of the control value. The $K^{+}$-induced activation of WDR cells was invariably suppressed after taurine administration. Intravenously administered strychnine remarkably reduced the enhanced response of WDR cell to natural stimuli resulting from intravenous administration of taurine. Also ${\beta}-alanine$ markedly activated the response of spinal dorsal horn cell to natural mechanical stimuli. These findings suggest that neutral amino acid and its derivative such as ${\beta}-alanine$ and taurine can enhance the response of WDR cells to different stimuli in cats.

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Development of Hydrogen-Storage Alloy by Mechanical Alloying of Mg and Ni (Mg과 Ni의 기계적인 합금화에 의한 수소 저장 합금의 개발)

  • Song, Myoung-Youp
    • Transactions of the Korean hydrogen and new energy society
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    • v.7 no.2
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    • pp.181-191
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    • 1996
  • Samples with the compositions of Mg-10wt.%Ni and Mg-25wt.%Ni were prepared by mechanical alloying in a planetary mill. $Mg_2Ni$ phase was formed in the mixture with hydriding dehydriding cycling. The activation of Mg-10wt.%Ni and Mg-25wt.%Ni was completed after n=7 and n=6 around, respectively, at 583K, $0{\sim}8barH_2$. Mg-10wt.% Ni and Mg-25wt. %Ni are considered as excellent hydrogen-storage materials with very high hydriding rates, high dehydriding rates and relatively large hydrogen-storage capacity. The effets of mechanical alloying and hydriding dehydriding cycling are considered the augmentation in the density of active nucleation sites and the diminution in the particle size.

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Formation and Hydrogen Absorption Properties of Intermetallic Mg-Ni Compound Nanoparticles (Mg-Ni 금속 간 화합물 나노입자의 형성과 수소저장 특성)

  • BAE, YOOGEUN;HWANG, CHULMIN;KIM, JONGSOO;DONG, XING LONG;KIM, SEWOONG;JUNG, YOUNGUAN
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.3
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    • pp.238-245
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    • 2017
  • Mg-Ni nanoparticles were synthesized by a physical vapor condensation method (DC arc-discharge) in a mixture of argon and hydrogen atmosphere, using compressed mixture of micro powders as the raw materials. The crystal phases, morphology, and microstructures of nanoparticles were analyzed by means of X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). It was found that the intermetallic compounds of $Mg_2Ni$ and $Mg_2Ni$ formed with existence of phases of Mg, Ni, and MgO in Mg-Ni nanoparticles. After one cycle of hydrogen absorption/desorption process (activation treatment), Mg-Ni nanoparticles exhibited excellent hydrogen absorption properties. $Mg_2Ni$ phase became the main phase by aphase transformation during the hydrogen treatments. The phenomenon of refinement of grain size in the nanoparticle was also observed after the hydrogen absorption/desorption processes, which was attributed to the effect of volume expansion/shrinkage and subsequent break of nanoparticles. Maximum hydrogen absorption contents are 1.75, 2.21 and 2.77 wt.% at 523, 573 and 623 K, respectively.

Numerical Investigation of Factors affecting Photoresist Stripping Process on the ITO Surface using the Spray Method (노즐 분사 방식의 ITO 표면 포토레지스트 박리과정 요인의 수치해석)

  • Kim, Joon Hyun;Lee, Joon Hyuck;Kang, Tae Seong;Joo, Gi-Tae;Kim, Young Sung;Jeong, Byung Hyun;Lee, Dae Won
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.26 no.2
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    • pp.158-165
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    • 2017
  • This study investigated spraying factors applicable to stripper usage. Cyclodextrine, as environment-friendly material, was included in the stripper composition. An efficient spray technology was applied for the Photoresist strip. For industrial applications, stripping requires a temperature below $50^{\circ}C$, a strip time within 50 s, and chemically stable activation. Spraying factors were organized considering many conditions-orifice diameter, working pressure (inlet speed), spray distance, and spray angle. For commercial practicability, the flow rate was limited to 3 L/min. The nozzle parameters were nozzle orifice diameter of 1.8-2.2 mm, spray distance of 40-60 mm, and injection speed of 0.7-1.2 m/s. Through the thermal spray movement of the fluid, the thermal boundary layer for a chemical reaction just above the ITO-glass surface and momentum region for sufficient agitation (above 4 m/s) was achieved.

Dynamic Mode Tuning of Ultrasonic Guided Wave Using an Array Transducer (배열 탐촉자를 사용한 유도초음파의 모드선정 기법)

  • Kim, Young-H.;Song, Sung-Jin;Park, Joon-Soo;Kim, Jae-Hee;Eom, Heung-Sup
    • Journal of the Korean Society for Nondestructive Testing
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    • v.25 no.1
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    • pp.20-26
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    • 2005
  • Ultrasonic guided waves have been widely employed for long range inspection of structures such as plates, rods and pipes. There are numerous modes with different wave velocities, and the appropriate mode selection is one of key techniques in the application of guided waves. In the present work, phase tuning by an array transducer was applied to generate ultrasonic guided waves. For this purpose, 8-channel ultrasonic pulser/receiver and their controller which enables sequential activation of each channels with given time delay were developed. Eight transducers were fabricated in order to generate guided waves by using an array transducer. The selective tuning of wave mode can be achieved by changing the interval between elements of an array transducer.

Hydrogen Absorption at a Low Temperature by MgH2 after Reactive Mechanical Grinding

  • Song, Myoung Youp;Lee, Seong Ho;Kwak, Young Jun;Park, Hye Ryoung
    • Korean Journal of Materials Research
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    • v.24 no.3
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    • pp.129-134
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    • 2014
  • Pure $MgH_2$ was milled under a hydrogen atmosphere (reactive mechanical grinding, RMG). The hydrogen storage properties of the prepared samples were studied at a relatively low temperature of 423 K and were compared with those of pure Mg. The hydriding rate of the Mg was extremely low (0.0008 wt% H/min at n = 4), and the $MgH_2$ after RMG had higher hydriding rates than that of Mg at 423 K under 12 bar $H_2$. The initial hydriding rate of $MgH_2$ after RMG at 423 K under 12 bar $H_2$ was the highest (0.08 wt% H/min) at n = 2. At n = 2, the $MgH_2$ after RMG absorbed 0.39 wt% H for 5 min, and 1.21 wt% H for 60 min at 423K under 12 bar $H_2$. At 573 K under 12 bar $H_2$, the $MgH_2$ after RMG absorbed 4.86 wt% H for 5 min, and 5.52 wt% H for 60 min at n = 2. At 573 K and 423 K under 1.0 bar $H_2$, the $MgH_2$ after RMG and the Mg did not release hydrogen. The decrease in particle size and creation of defects by reactive mechanical grinding are believed to have led to the increase in the hydriding rate of the $MgH_2$ after RMG at a relatively low temperature of 423 K.