Browsing by Author "Hsu, Yu-Chen"

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A Review of Intervention Studies On Technology-assisted Instruction From 2005-2010
(2013-07-01)
Wu, Ying-Tien
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Hou, Huei-Tse
;
Hwang, Fu-Kwun
;
Lee, Min-Hsien
;
Lai, Chih-Hung
By reviewing papers published in five important SSCI journals from 2005 to 2010, this study aimed to provide insights into intervention studies on technology-assisted instruction. It was found that still relatively little research on educational technology which addresses the effects of specific instructional interventions on student learning was conducted during this period. Moreover, most reviewed studies were conducted in higher education, rather than in high school, elementary school, or adult education contexts. The two subject domains, science and engineering (including computer studies), were most frequently involved in these studies, the majority of which addressed achievement as research (learning outcome) foci, while relatively fewer studies investigated students' learning process or affective outcomes. Regarding technology adoption, this study revealed that, in both the 2005-2007 and 2008-2010 periods, technologies for specific instructional purposes(e.g., a specially designed system for online collaborative writing) were more frequently adopted than those for general purposes (such as PowerPoint). This study also reveals that technology-mediated interpersonal interactions are commonly utilized in these intervention studies, with the focus mainly on student-student interactions.
Blending Homopolymers for Controlling the Morphology Transitions of Block Copolymer Nanorods Confined in Cylindrical Nanopores
(2017-06-21)
Cheng, Ming-Hsiang
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Hsu, Yu-Chen
;
Chang, Chun-Wei
;
Ko, Hao-Wen
;
Chung, Pei-Yun
The microphase separation of block copolymers in confined geometries has been widely investigated over the last few decades. The controllability and versatility of the confinement-induced morphologies, however, are still difficult to be achieved because of the limited experimental parameters in the process of fabricating the confined nanostructures. In this work, we study the morphology transitions of lamellae forming polystyrene-block-polydimethylsiloxane (PS-b-PDMS) nanorods confined in the nanopores of anodic aluminum oxide (AAO) templates. The nanorods are formed by solvent-assisted template wetting, and the morphologies are compared to those in the bulk state. By blending PS-b-PDMS with homopolystyrene (hPS), the morphologies of the nanorods can be controlled because of the changes of the effective volume fractions. Special morphology transitions from concentric lamellar morphology, to multihelical morphology, and finally to spherical-like morphology are observed by increasing the weight ratios of hPS. hPS with different molecular weights is also applied to investigate the effect of hPS on the morphologies of the PS-b-PDMS/hPS blend nanostructures. The unusual morphologies are further confirmed by a selective removal process, which also generates nanochannels for possible refilling with functional materials.
Synthesis and Isolation of an Acyclic Tridentate Bis(pyridine)carbodicarbene and Studies on Its Structural Implications and Reactivities
(2015-02-16)
Hsu, Yu-Chen
;
Shen, Jiun-Shian
;
Lin, Bo-Chao
;
Chen, Wen-Ching
;
Chan, Yi-Tsu
The simple synthetic development of acyclic pincer bis(pyridine)carbodicarbene is depicted herein. Presented is the first isolated structural pincer carbodicarbene with a C-C-C angle of 143 degrees, larger than the monodentate framework. More importantly, theoretical analysis showed that this carbodicarbene embodies a more allene-like character. Palladium complexes supported by this pincer ligand are active catalysts for Heck-Mizoroki and Suzuki-Miyaura coupling reactions.
Synthetic Modification of Acyclic Bent Allenes (Carbodicarbenes) and Further Studies on Their Structural Implications and Reactivities
(2013-04-22)
Chen, Wen-Ching
;
Hsu, Yu-Chen
;
Lee, Ching-Yu
;
Yap, Glenn P. A.
;
Ong, Tiow-Gan
The paper describes the synthetic development of Bertrand-type acyclic carbodicarbene scaffolds derived from an unsymmetrical bis(benzimidazol-2-yl)methane bearing two sterically demanding pendant arms, isopropyl (6a) or cyclohexyl (6b). X-ray crystallographic analysis shows that the impact of these pendant arms on the overall structural parameters of carbodicarbenes is minimal. The chemical reactivity of the carbodicarbenes was evaluated with iodomethane to afford compound 7, illustrating its nudeophilic properties. Finally, experiments were also undertaken to investigate the coordination ability of carbodicarbene toward the formation of rhodium carbonyl (10) and palladium allyl complexes (11). The crystal structures of the metal complexes have been determined, revealing that their metal-carbene distances are elongated only slightly, this fact was rationalized on the basis of geometrical steric considerations with regard to the ligand.
The Elusive Three-Coordinate Dicationic Hydrido Boron Complex
(2014-01-22)
Chen, Wen-Ching
;
Lee, Ching-Yu
;
Lin, Bo-Chao
;
Hsu, Yu-Chen
;
Shen, Jiun-Shian
The formation of a hitherto unknown three-coordinate dicationic hydrido boron complex is described. Interestingly, supporting ligand carbodicarbene gave unprecedented reaction with BH3 without using more highly electrophilic Lewis acid precursors. Spectroscopic, crystallographic, and computational analysis was performed to understand the electronic features of these species.