Browsing by Issue Date, starting with "2015-01-22"

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Scaffolding Middle School Students\' Construction of Scientific Explanations: Comparing a cognitive versus a metacognitive evaluation approach
(2015-01-22)
Wang, Chia-Yu
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教育研究所
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Institute of Education
This study investigated the effects of scaffolds as cognitive prompts and as metacognitive evaluation on seventh-grade students\' growth of content knowledge and construction of scientific explanations in five inquiry-based biology activities. Students\' scores on multiple-choice pretest and posttest and worksheets for five inquiry-based activities were analyzed. The results show that the students\' content knowledge in all conditions significantly increased from the pretest to posttest. Incorporating cognitive prompts with the explanation scaffolds better facilitated knowledge integration and resulted in greater learning gains of content knowledge and better quality evidence and reasoning. The metacognitive evaluation instruction improved all explanation components, especially claims and reasoning. This metacognitive approach also significantly reduced students\' over- or underestimation during peer-evaluation by refining their internal standards for the quality of scientific explanations. The ability to accurately evaluate the quality of explanations was strongly associated with better performance on explanation construction. The cognitive prompts and metacognitive evaluation instruction address different aspects of the challenges faced by the students, and show different effects on the enhancement of content knowledge and the quality of scientific explanations. Future directions and suggestions are provided for improving the design of the scaffolds to facilitate the construction of scientific explanations.
Effect of driven frequency on flow and heat transfer of an impinging synthetic air jet
(2015-01-22)
Liu, Yao-Hsien
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Tsai, Shu-Yao
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Wang, Chi-Chuan
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機械工程學系
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Department of Mechanical Engineering
In this study, impingement heat transfer from a synthetic air jet on a heated surface was experimentally studied. A synthetic jet provides a high heat transfer coefficient and a compact design, which is suitable for the thermal management of electronic devices. The synthetic jet is produced by the high frequency oscillating motion (200-800 Hz) of a piezoelectric actuator, and a jet Reynolds number ranging from 500 to 1300. The instantaneous and time-averaged velocity profiles of the synthetic jet issuing from the jet hole were measured using a hot wire anemometer. The jet hole diameter was 3 mm and the jet-to-surface spacing (Z/d) ranged from 0 to 25. The excitation frequency effect, jet-to-surface spacing, and jet Reynolds number were tested. The heat transfer enhancement of the synthetic jet was at least double the natural convective heat transfer. At a small jet-to-surface spacing, the warm air circulates inside small spaces, jeopardizing heat transfer. An optimal driven frequency of 600 Hz in this study provided the highest jet flow rates and heat transfer enhancement. (C) 2014 Elsevier Ltd. All rights reserved.
Surface characteristics and biofunctionality of a novel high-performance, hydrophilic Jeffamine-added fluoro-containing polyimide for biomedical applications
(2015-01-24)
Lo, Teng-Yuan
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Wang, Yen-Jen
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Liu, Dean-Mo
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Whang, Wha-Tzong
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材料科學與工程學系
A brand-new class of Jeffamine-modified fluorocontaining polyimide (6FPI-J(x) series, where x ranges from 10, 20, and 30 % by weight) was developed in this study. The existing pristine fluoro-containing polyimide (6FPI) is a flexible and high-performance polymer with low surface energy for advanced engineering applications. Although it has been considered a promising biomaterial for its good blood compatibility, it has known to be toxic to normal cells. Here, we modified 6FPI [with -C (CF3)(2)-group on backbone] with a hydrophilic diamine monomer, Jeffamine, denoted as 6FPI-J(x), where x is the molar percentage of the total diamines. The newly synthesized 6FPI-J(x) series was systematically characterized in terms of surface properties included surface texture, chemistry, potential, and charging. Besides, the 6FPI-J(x) copolymer exhibited good mechanical and stability as pristine 6FPI. With the addition of Jeffamine (x=10 %), 6FPI-J(10) displayed considerably improved blood and cell compatibility compared to 6FPI, which was explainable as a combined effect of morphological texture and chemical environment of resulting surface. The new class of 6FPI-J(x) exhibited excellent solubility toward a number of organic solvents, which rendered the 6FPI-J(10) a great potential candidate as a biocompatible coating for implantable medical devices and also for potential therapeutic applications.
Arthropod steroid hormone (20-Hydroxyecdysone) suppresses IL-1 beta-induced catabolic gene expression in cartilage
(2015-01-24)
Sheu, Shiow-Yunn
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Ho, Shin-Rong
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Sun, Jui-Sheng
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Chen, Ching-Yun
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Ke, Cherng-Jyh
Background: In osteoarthritis (OA), the imbalance of chondrocytes' anabolic and catabolic factors can induce cartilage destruction. Interleukin-1 beta (IL-1 beta) is a potent pro-inflammatory cytokine that is capable of inducing chondrocytes and synovial cells to synthesize MMPs. The hypoxia-inducible factor-2alpha (HIF-2alpha, encoded by Epas1) is the catabolic transcription factor in the osteoarthritic process. The purpose of this study is to validate the effects of ecdysteroids (Ecd) on IL-1 beta-induced cartilage catabolism and the possible role of Ecd in treatment or prevention of early OA. Methods: Chondrocytes and articular cartilage was harvested from newborn ICR mice. Ecd effect on chondrocytes viability was tested and the optimal concentration was determined by MTT assay. The effect of HIF-2 alpha (EPAS1) in cartilage catabolism simulated by IL-1 beta (5 ng/ml) was evaluated by articular cartilage explants culture. The effects of Ecd on IL-1 beta-induced inflammatory conditions and their related catabolic genes expression were analyzed. Results: Interleukin-1 beta (IL-1 beta) treatment on primary mouse articular cartilage explants enhanced their Epas1, matrix metalloproteinases (MMP-3, MMP-13) and ADAMTS-5 genes expression and down-regulated collagen type II (Col2a1) gene expression. With the pre-treatment of 10(-8)M Ecd, the catabolic effects of IL-1 beta on articular cartilage were scavenged. Conclusion: In conclusions, Ecd can reduce the IL-1 beta-induced inflammatory effect of the cartilage. Ecd may suppress IL-1 beta-induced cartilage catabolism via HIF-2a pathway.
ZnO-graphene composites as practical photocatalysts for gaseous acetaldehyde degradation and electrolytic water oxidation
(2015-01-25)
Chen, Yu-Chih
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Katsumata, Ken-ichi
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Chiu, Yi-Hsuan
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Okada, Kiyoshi
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Matsushita, Nobuhiro
A facile, green one-pot hydrothermal method has been developed to prepare ZnO-reduced graphene oxide (rGO) composites with controllable rGO content. Time-resolved photoluminescence spectra revealed that an increased electron-transfer rate constant was observed for ZnO-rGO with increasing rGO contents, suggesting that an increased number of photoexcited charge carriers were separated and available for photocatalysis utilization. The photocatalytic properties of the ZnO-rGO composites were investigated by using gaseous acetaldehyde (CH3CHO), a typical volatile organic compound (VOC), as the test pollutant. This is the first time that ZnO-rGO composites have been used as photocatalysts for gaseous CH3CHO degradation. Compared to pure ZnO, ZnO-rGO composites with suitable rGO contents (1.0 and 3.0 wt%) displayed significantly enhanced photocatalytic activity in both CH3CHO degradation and CO2 generation. This enhancement was ascribed to the rGO support that can promote the carrier utilization efficiency of ZnO by readily accepting the photoexcited electrons from ZnO. As a result, abundant photogenerated holes remained on the ZnO and were available for participation in the CH3CHO photodegradation. Furthermore, the photoactivity of ZnO-rGO toward electrolytic water oxidation was evaluated. The results showed that ZnO-rGO composites achieved 50% increase in water oxidation current over pure ZnO under white light illumination. The demonstration from this work may facilitate the use of ZnO-rGO composites in photodegradation of VOCs as well as for photoelectrochemical applications, which is imperative from the environmental and energetic points of view. (C) 2014 Elsevier B.V. All rights reserved.
Non-invasive biopsy of doped-ions inside optical substrate by modified two-photon microscopy
(2015-01-26)
Wang, Yao-Chin
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Chen, Hsiang-Ning
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Li, Wang-Yang
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Chan, Ming-Che
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光電系統研究所
Doped-ion based optical elements play key roles in optical signal processes, including amplification, absorption, wavelength-filtering, lighting, and polarizing plate. Non-invasively mapping the spatial distribution of the ion concentrations in these optical elements is highly desirable either during the fabrication process or to determine their optical qualities. In this work, we applied modified two-photon fluorescence (mTPF) microscopy to trace the ion-distributions deep inside the optical elements. For demonstration purposes, polyvinyl alcohol (PVA) polymer films inside polarizing plates are taken as an example, where the spatial distributions of Iodine-dyed ions were measured by the m-TPF microscope in a fast and non-invasive way. The durability of the polarizer films can be distinguished from the axial distribution of the Iodine-dyed ions, without the need to perform a biopsy. This proposed method and demonstrated results show great potential for monitoring the spatial distributions of doped-ions in the optical elements quickly and non-destructively, which would be of great benefit in both scientific research and industrial applications. (C) 2015 Optical Society of America
Hexagonal liquid crystal lens array for 3D endoscopy
(2015-01-26)
Hassanfiroozi, Amir
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Huang, Yi-Pai
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Javidi, Bahram
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Shieh, Han-Ping D.
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光電工程學系
A liquid crystal lens array with a hexagonal arrangement is investigated experimentally. The uniqueness of this study exists in the fact that using convex-ring electrode provides a smooth and controllable applied potential profile across the aperture to manage the phase profile. We observed considerable differences between flat electrode and convex-ring electrode; in particular the lens focal length is variable in a wider range from 2.5cm to infinity. This study presents several noteworthy characteristics such as low driving voltage; 30 mu m cell gap and the lens is electrically switchable between 2D/3D modes. We demonstrate a hexagonal LC-lens array for capturing 3D images by using single sensor using integral imaging. (C) 2015 Optical Society of America
High directional backlight using an integrated light guide plate
(2015-01-26)
Wang, Yi-Jun
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Ouyang, Shi-Hong
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Chao, Wei-Chung
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Lu, Jian-Gang
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Shieh, Han-Ping D.
A high directional backlight system that combined a composite microstructure light guide plate (LGP) with a collimated light source was proposed for eco-displays. The collimated planar light was expanded from a point light source and guided towards the normal direction by utilizing the micro-prism array on LGP. High uniformity of spatial luminous, 91%, with a narrow viewing cone of +/- 4 degrees can be achieved without additional optical films. Moreover, compared to the conventional backlight, only 5% of power consumption was needed to keep the same luminance, hence, the optical efficiency increased by a factor of 1.47. (C) 2015 Optical Society of America
Utilization of multi-band OFDM modulation to increase traffic rate of phosphor-LED wireless
(2015-01-26)
Yeh, Chien-Hung
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Chen, Hsing-Yu
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Chow, Chi-Wai
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Liu, Yen-Liang
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光電工程學系
To increase the traffic rate in phosphor-LED visible light communication (VLC), a multi-band orthogonal frequency division multiplexed (OFDM) modulation is first proposed and demonstrated. In the measurement, we do not utilize optical blue filter to increase modulation bandwidth of phosphor-LED in the VLC system. In this proposed scheme, different bands of OFDM signals are applied to different LED chips in a LED lamp, this can avoid the power fading and nonlinearity issue by applying the same OFDM signal to all the LED chips in a LED lamp. Here, the maximum increase percentages of traffic rates are 41.1%, 17.8% and 17.8% under received illuminations of 200, 500 and 1000 Lux, respectively, when the proposed three-band OFDM modulation is used in the VLC system. In addition, the analysis and verification by experiments are also performed. (C) 2015 Optical Society of America
Wireless intraocular pressure monitoring device, and detecting module thereof
(2015-01-27)
Huang Tzuen-Hsi
;
Lin Ying-Chun
;
Su Wei-Shang
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Cheng Huey-Wen
;
Huang Hong-Yi
A wireless intraocular pressure monitoring device includes reflecting and detecting modules. The reflecting module includes a soft contact lens having a curvature corresponding to that of a cornea while worn. A metal layer is embedded in and deformable with the soft contact lens. The detecting module includes two waveguides, an oscillator, and a converting unit. The oscillator is operable to generate oscillation signals having a frequency dependent on an equivalent impedance of the waveguides such that the equivalent impedance corresponds to intraocular pressure. The converting unit is operable for receiving and converting the oscillation signals into an output signal corresponding to the intraocular pressure.
Cyclic code decoding method and cyclic code decoder
(2015-01-27)
Lin Yi-Min
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Hsu Chih-Hsiang
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Chang Hsie-Chia
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Lee Chen-Yi
In a cyclic code decoding method, a decoder analyzes a received codeword to identify unreliable symbols in the codeword, and sets candidate syndrome patterns accordingly. Then, a syndrome calculator calculates evaluated syndrome values associated with one of the candidate syndrome patterns, and an error location polynomial (ELP) generator generates an ELP according to the syndrome values. An error correction device corrects the errors in the codeword according to the ELP when a degree of the ELP is not more than a threshold value, and the syndrome calculator adjusts the syndrome values and the ELP generator generates another ELP according to the adjusted syndrome values when otherwise.
A Multitheragnostic Nanobubble System to Induce Blood-Brain Barrier Disruption with Magnetically Guided Focused Ultrasound
(2015-01-27)
Huang, Hsin-Yang
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Liu, Hao-Li
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Hsu, Po-Hung
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Chiang, Chih-Sheng
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Tsai, Chih-Hung
Method and system for offloading a computation to other computing units in the same device or to a server on a network based upon a computing time and a power consumption of each of the computing units and the server
(2015-01-27)
Lin Ying-Dar
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Huang Ting-Jun
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Lai Yuan-Cheng
;
Chu Tsung-Hsien
A decision method considering time and power consumption for offloading computations is provided. The method includes: obtaining a computing mission; obtaining a plurality of static effect factors from an effect factor table; collecting a plurality of dynamic effect factors. The method also includes: generating power consumptions and computing time that each of the computing unit and each of the server consumes according to the dynamic effect factors and the static effect factors; calculating cost values of executing the computing mission according to the power consumptions and the computing time; determining a target unit to execute the computing mission according to the cost values, in which the target unit is a computing unit or a server; executing the computing mission by the target unit. Therefore, the power consumptions and the computing time are simultaneously considered, and computations are adequately allocated to one of the computing unit and the servers.
ZnSe center dot 0.5N(2)H(4) Hybrid Nanostructures: A Promising Alternative Photocatalyst for Solar Conversion
(2015-01-28)
Chen, Yu-Chih
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Liu, Tao-Cheng
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Hsu, Yung-Jung
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材料科學與工程學系
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Department of Materials Science and Engineering
As the molecular precursor of ZnSe, ZnSe center dot 0.5N(2)H(4) inorganic-organic hybrids have received relatively less attention due to the feasibility of their further processing and decomposition into pure-phase ZnSe. Here we demonstrated that ZnSe center dot 0.5N(2)H(4) hybrid nanostructures, which were prepared using a facile hydrazine-assisted hydrothermal method, may practically harvest solar energy for photoconversion applications. By modulating the volume ratio of hydrazine hydrate to deionized water employed in the synthesis, the morphology of the grown ZnSe center dot 0.5N(2)H(4) can be varied, which included nanowires, nanobelts and nanoflakes. With the relatively long exciton lifetime and highly anisotropic structure, ZnSe center dot 0.5N(2)H(4) nanowires performed much better in the photodegradation of rhodamine B than the other two counterpart products. As compared to pure ZnSe nanoparticles and single-phase ZnSe nanowires obtained from further processing ZnSe center dot 0.5N(2)H(4), the ZnSe center dot 0.5N(2)H(4) hybrid nanowires exhibited superior photocatalytic performance under visible light illumination. The hybrid nanowires were further decorated with Au particles to endow them with structural and compositional diversities. Time-resolved photoluminescence spectra suggested that almost 40% of the photoexcited electrons in ZnSe center dot 0.5N(2)H(4) nanowires can be transported to the decorated Au, which enabled a fuller extent of participation of charge carriers in the photocatalytic process and thus conduced to a significant enhancement in the photocatalytic activity. The demonstrations from this work illustrate that ZnSe center dot 0.5N(2)H(4) hybrid nanostructures can serve as a versatile photocatalyst platform for advanced photocatalytic applications.
Revealing the flexoelectricity in the mixed-phase regions of epitaxial BiFeO3 thin films
(2015-01-28)
Cheng, Cheng-En
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Liu, Heng-Jui
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Dinelli, Franco
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Chen, Yi-Chun
;
Chang, Chen-Shiung
Understanding the elastic response on the nanoscale phase boundaries of multiferroics is an essential issue in order to explain their exotic behaviour. Mixed-phase BiFeO3 films, epitaxially grown on LaAlO3 (001) substrates, have been investigated by means of scanning probe microscopy to characterize the elastic and piezoelectric responses in the mixed-phase region of rhombohedral-like monoclinic (M-I) and tilted tetragonal-like monoclinic (M-II,M-tilt) phases. Ultrasonic force microscopy reveal that the regions with low/ high stiffness values topologically coincide with the M-I/M-II,M-tilt phases. X-ray diffraction strain analysis confirms that the M-I phase is more compliant than the M-II,(tilt) one. Significantly, the correlation between elastic modulation and piezoresponse across the mixed-phase regions manifests that the flexoelectric effect results in the enhancement of the piezoresponse at the phase boundaries and in the M-I regions. This accounts for the giant electromechanical effect in strained mixed-phase BiFeO3 films.
A polarized bifocal switch based on liquid crystals operated electrically and optically
(2015-01-28)
Chen, Hung-Shan
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Lin, Yi-Hsin
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Chang, Chia-Ming
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Wang, Yu-Jen
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Srivastava, Abhishek Kumar
A polarized bifocal switch based on liquid crystals (LC) operated electrically and optically is demonstrated. The bifocal switch mainly consists of two parts: a LC layer as a polarization switch and two polymeric layers for modulation of polarization dependent spatial phase difference which results in a positive or a negative lensing effect. The orientations of the LC molecules in the polarization switch are manipulated either in electrically switching (ES) mode or optically rewritten (ORW) mode. The bifocal switch with an aperture size of 10mm exhibits two discrete lens powers (-1.39 Diopter and +0.7 Diopter) with different polarization states no matter in ES mode or in ORW mode. ORW mode is also a bistable mode. The related mechanism and electro-optical performance are discussed and demonstrated. Such a versatile optical switch is capable of not only switching between a positive lens power and a negative lens power, but also switching between two linear polarization states which can be useful in optical systems. The potential applications are for optical systems, wearable devices and ophthalmic lenses. (C) 2015 AIP Publishing LLC.
Unipolar resistive switching behaviors and mechanisms in an annealed Ni/ZrO2/TaN memory device
(2015-01-28)
Tsai, Tsung-Ling
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Ho, Tsung-Han
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Tseng, Tseung-Yuen
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電子物理學系
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Department of Electrophysics
The effects of Ni/ZrO2/TaN resistive switching memory devices without and with a 400 degrees C annealing process on switching properties are investigated. The devices exhibit unipolar resistive switching behaviors with low set and reset voltages because of a large amount of Ni diffusion with no reaction with ZrO2 after the annealing process, which is confirmed by ToF-SIMS and XPS analyses. A physical model based on a Ni filament is constructed to explain such phenomena. The device that undergoes the 400 degrees C annealing process exhibits an excellent endurance of more than 1.5 x 10(4) cycles. The improvement can be attributed to the enhancement of oxygen ion migration along grain boundaries, which result in less oxygen ion consumption during the reset process. The device also performs good retention up to 10(5) s at 150 degrees C. Therefore, it has great potential for high-density nonvolatile memory applications.
RNAcentral: an international database of ncRNA sequences
(2015-01-28)
Petrov, Anton I.
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Kay, Simon J. E.
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Gibson, Richard
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Kulesha, Eugene
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Staines, Dan
The field of non-coding RNA biology has been hampered by the lack of availability of a comprehensive, up-to-date collection of accessioned RNA sequences. Here we present the first release of RNAcentral, a database that collates and integrates information from an international consortium of established RNA sequence databases. The initial release contains over 8.1 million sequences, including representatives of all major functional classes. A web portal (http://rnacentral.org) provides free access to data, search functionality, cross-references, source code and an integrated genome browser for selected species.
Asymmetric Engagement of Amygdala and Its Gamma Connectivity in Early Emotional Face Processing
(2015-01-28)
Liu, Tai-Ying
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Chen, Yong-Sheng
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Hsieh, Jen-Chuen
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Chen, Li-Fen
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資訊工程學系
The amygdala has been regarded as a key substrate for emotion processing. However, the engagement of the left and right amygdala during the early perceptual processing of different emotional faces remains unclear. We investigated the temporal profiles of oscillatory gamma activity in the amygdala and effective connectivity of the amygdala with the thalamus and cortical areas during implicit emotion-perceptual tasks using event-related magnetoencephalography (MEG). We found that within 100 ms after stimulus onset the right amygdala habituated to emotional faces rapidly (with duration around 20-30 ms), whereas activity in the left amygdala (with duration around 50-60 ms) sustained longer than that in the right. Our data suggest that the right amygdala could be linked to autonomic arousal generated by facial emotions and the left amygdala might be involved in decoding or evaluating expressive faces in the early perceptual emotion processing. The results of effective connectivity provide evidence that only negative emotional processing engages both cortical and subcortical pathways connected to the right amygdala, representing its evolutional significance (survival). These findings demonstrate the asymmetric engagement of bilateral amygdala in emotional face processing as well as the capability of MEG for assessing tha-lamo-cortico-limbic circuitry.
Potent Antibacterial Nanoparticles for Pathogenic Bacteria
(2015-01-28)
Lai, Hong-Zheng
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Chen, Wei-Yu
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Wu, Ching-Yi
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Chen, Yu-Chie
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應用化學系
Antibiotic-resistant bacteria have emerged because of the prevalent use of antibacterial agents. Thus, new antibacterial agents and therapeutics that can treat bacterial infections are necessary. Vancomycin is a potent antibiotic. Unfortunately, some bacterial strains have developed their resistance toward vancomycin. Nevertheless, it has been demonstrated that vancomycin-immobilized nanoparticles (NPs) are capable to be used in inhibition of the cell growth of vancomycin-resistant bacterial strains through multivalent interactions. However, multistep syntheses are usually necessary to generate vancomycin-immobilized NPs. Thus, maintaining the antibiotic activity of vancomycin when the drug is immobilized on the surface of NPs is challenging. In this study, a facile approach to generate vancomycin immobilized gold (Van-Au) NPs through one-pot stirring of vancomycin with aqueous tetrachloroauric acid at pH 12 and 25 degrees C for 24 h was demonstrated. Van-Au NPs (8.4 +/- 1.3 nm in size) were readily generated. The generated Van-Au NPs maintained their antibiotic activities and inhibited the cell growth of pathogens, which included Gram-positive and Gram-negative bacteria as well as antibiotic-resistant bacterial strains. Furthermore, the minimum inhibitory concentration of the Van-Au NPs against bacteria was lower than that of free-form vancomycin. Staphylococcus aureus-infected macrophages were used as the model samples to examine the antibacterial activity of the Van-Au NPs. Macrophages have the tendency to engulf Van-Au NPs through endocytosis. The results showed that the cell growth of S. aureus in the macrophages was effectively inhibited, suggesting the potential of using the generated Van-Au NPs as antibacterial agents for bacterial infectious diseases.