Browsing by Author "Wu, Chia-Hua"

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All-in-one visual and computer decoding of multiple secrets: translated-flip VC with polynomial-style sharing
(2017-06-01)
Wu, Chia-Hua
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Lee, Suiang-Shyan
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Lin, Ja-Chen
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資訊工程學系
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Department of Computer Science
This all-in-one hiding method creates two transparencies that have several decoding options: visual decoding with or without translation flipping and computer decoding. In visual decoding, two less-important (or fake) binary secret images S1 and S2 can be revealed. S1 is viewed by the direct stacking of two transparencies. S2 is viewed by flipping one transparency and translating the other to a specified coordinate before stacking. Finally, important/true secret files can be decrypted by a computer using the information extracted from transparencies. The encoding process to hide this information includes the translated-flip visual cryptography, block types, the ways to use polynomial-style sharing, and linear congruential generator. If a thief obtained both transparencies, which are stored in distinct places, he still needs to find the values of keys used in computer decoding to break through after viewing S1 and/or S2 by stacking. However, the thief might just try every other kind of stacking and finally quit finding more secrets; for computer decoding is totally different from stacking decoding. Unlike traditional image hiding that uses images as host media, our method hides fine gray-level images in binary transparencies. Thus, our host media are transparencies. Comparisons and analysis are provided. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Multi-Stimuli Responsive FRET Processes of Bifluorophoric AlEgens in an Amphiphilic Copolymer and Its Application to Cyanide Detection in Aqueous Media
(2020-03-04)
Nhien, Pham Quoc
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Chou, Wei-Lun
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Cuc, Tu Thi Kim
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Khang, Trang Manh
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Wu, Chia-Hua
A novel amphiphilic aggregation-induced emission (AIE) copolymer, that is, poly(NIPAM-co-TPE-SP), consisting of N-isopropylacrylamide (NIPAM) as a hydrophilic unit and a tetraphenylethylene-spiropyran monomer (TPE-SP) as a bifluorophoric unit is reported. Upon UV exposure, the close form of non-emissive spiropyran (SP) in poly(NIPAM-co-TPE-SP) can be photo-switched to the open form of emissive merocyanine (MC) in poly(NIPAM-co-TPE-MC) in an aqueous solution, leading to ratiometric fluorescence of AlEgens between green TPE and red MC emissions at 517 and 627 nm, respectively, via Forster resonance energy transfer (FRET). Distinct FRET processes of poly(NIPAM-co-TPE-MC) can be observed under various UV and visible light irradiations, acid-base conditions, thermal treatments, and cyanide ion interactions, which are also confirmed by theoretical studies. The subtle perturbations of environmental factors, such as UV exposure, pH value, temperature, and cyanide ion, can be detected in aqueous media by distinct ratiometric fluorescence changes of the FRET behavior in the amphiphilic poly(NIPAM-co-TPE-MC). Moreover, the first FRET sensor polymer poly(NIPAM-co-TPE-MC) based on dual AlEgens of TPE and MC units is developed to show a very high selectivity and sensitivity with a low detection limit (LOD = 0.26 mu M) toward the cyanide ion in water, which only contain an approximately 1% molar ratio of the bifluorophoric content and can be utilized in cellular bioimaging applications for cyanide detections.
Tooth bleaching by using a helium-based low-temperature atmospheric pressure plasma jet with saline solution
(2017-11-01)
Cheng, Yun-Chien
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Wu, Chia-Hua
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Liu, Chih-Tung
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Lin, Chia-Yung
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Chiang, Hsuan-Ping
In this study, tooth bleaching was performed by using a helium-based low temperature atmospheric-pressure plasma jet (He-APPJ) with saline solution to avoid ozone and hydrogen peroxide (H2O2) harm. In this study, tooth samples were treated through three approaches, namely a helium flow with saline, H2O2 gel, and He-APPJ with saline. The bleaching efficacy of the He-APPJ treatment was the highest among the three groups. Furthermore, scanning electron microscopy images showed that enamel treated with He-APPJ was much less damaged than that treated with H2O2 gel. In addition, ozone tests showed that APPJ produced little ozone (<0.35ppm). In conclusion, He-APPJ with saline solution achieves higher bleaching efficacy and is less harmful than methods that use H2O2 gel.