8,260 research outputs found
An evaluation of the microstructure and microhardness in an Al–Zn–Mg alloy processed by ECAP and post‐ECAP heat treatments
No full textHerein the microstructure evolution and microhardness variations in a peak‐aged Al–Zn–Mg alloy after equal‐channel angular pressing (ECAP) for 1–8 passes followed by heat treatments at temperatures of 393–473 K for 5–20 h are examined. The results show that ECAP processing hardens the alloy, and the hardness increases with each pass due to grain refinement, the formation of large numbers of fine precipitates, and the introduction of a high dislocation density. Post‐ECAP annealing at 393 K up to 20 h after 1 and 4 passes of ECAP leads to a further increase in microhardness and this increase is substantial for an annealing time of 20 h after 1 pass due primarily to the extensive formation of a nano‐sized η′ phase. After ECAP for 8 passes, post‐ECAP annealing at 393 K for 5 h or more leads to softening due to the occurrence of recrystallization and the transformation of fine η′ to coarse η. Post‐ECAP anneals at the higher temperatures of 423 and 473 K are not capable of producing high hardness values
Achieving an excellent combination of strength and plasticity in a low carbon steel through dynamic plastic deformation and subsequent annealing
No full textAn investigation was conducted to evaluate the effect of dynamic plastic deformation (DPD) and post-DPD annealing on the microstructural and mechanical properties of a tempered low carbon steel. The results showed that ultrafine-grained structures consisting of elongated martensitic laths and sub-grains are achieved after DPD processing. The amounts and sizes of carbides in the steels, identified as (Fe,Cr,Mn,Mo)
3C, decreased markedly with DPD straining due to their fragmentation and dissolution but a large number of finer carbides appeared due to re-precipitation during subsequent annealing. A simultaneous improvement in the strength and plasticity was obtained at DPD strains below ∼0.8. This increase in strength by ∼30–60% is mainly attributed to grain boundary strengthening, dislocation strengthening while the good plasticity is due to more active sliding systems, a reduction in the stress concentration during loading because of the amount decreasing of M
3C distributed along the interfaces, the increase of crack propagation resistance by more grain boundaries and the energy released through the occurrence of delamination fracture. After post-DPD annealing both the strength and plasticity improved compared with the as-received steel. Strengths higher by ∼20–39% were attributed to a combination of grain boundary strengthening, dislocation strengthening and precipitation strengthening derived from the re-precipitation of fine and dispersed carbides. The dislocation recovery occurring during annealing led to a decrease in strength compared with that before annealing. The incremental increase in plasticity is attributed to a combination of further active slip systems, a decreasing dislocation density and a dispersed distribution of finer carbides.
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Strain rate dependence of compressive behavior in an Al-Zn-Mg alloy processed by ECAP
No full text
Experiments were conducted to study the compressive mechanical properties of an Al-Zn-Mg alloy after solid solution treatment and equal-channel angular pressing (SS-ECAP) using strain rates ranging from 1.0 × 10
−3
to 3.0 × 10
3
s
−1
. The results show that SS-ECAP processing enhances the compressive strength due to the high dislocation density, large numbers of fine precipitates and grain refinement. The alloy in both the peak-aged (as-received) and the SS-ECAP states shows a strain rate strengthening effect such that the strain rate sensitivity increases with increasing strain rate. The high volume fraction of fine precipitates in the SS-ECAP alloy decreases the strain rate sensitivity. The coarse precipitates in the peak-aged alloy are fragmented while their sizes increase in the SS-ECAP alloy due to dynamic precipitation assisted by the high density of dislocations during compressive testing. With increasing strain rate, the size of the precipitates further increases for the SS-ECAP alloy and this is influenced by accelerated dislocation motion. During compression, the T (Al
20
Cu
2
Mn
3
) and E (Al
18
Mg
3
Cr
2
) phases evolve into a new tetragonal phase containing Mg, Mn, Cr and Zn with Al.
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Microstructure and mechanical properties of an Fe–Mn–Al–C lightweight steel after dynamic plastic deformation processing and subsequent aging
No full textAn austenitic low-density steel was processed by dynamic plastic deformation (DPD) over the strain range from 0.25 to 0.75 followed by aging at 450°C and then it was subjected to compressive testing at strain rates of 1.0 × 10-3 − 2.0 × 103 s-1. The results show that fine grain structures with high density dislocations are achieved after DPD processing. After aging, the grain size increased slightly together and there was an additional marginal decrease in the dislocation density. κ-carbides only appeared in the samples after DPD processing at the strain of 0.75 and after subsequent aging. Submicron-sized (Nb, Mo)C particles existed in the matrix before DPD and there was no change in size and distribution during DPD processing and post-DPD aging. The yield strengths of the steels after DPD at different strain rates increased significantly by ~120-190% compared with the as-received sample, where this is mainly due to a combination of dislocation strengthening and grain boundary strengthening. For the steel processed by DPD at strain of 0.75, there was an additional precipitation strengthening of κ-carbides besides the dislocation strengthening and grain boundary strengthening, and this produced an increase of over ~900 MPa in yield strength by comparison with the as-received steel. After aging, the yield strength decreased slightly due to a reduction in the dislocation density and a slight coarsening of the grains, except for samples after DPD at a strain of 0.75 which showed a slight increase in strength due to further κ precipitation. The strain rate strengthening effect and strain hardening ability were also analyzed
An Interview with an Author and Editor: The View from Taiwan
No full textORCID Engagement Manager Asia-Pacific, Estelle Cheng, recently spoke with Wen-Yau Cathy Lin, an academic, author and scholarly journal editor about ORCID and its use in Taiwan
Chinese Cooking with Theresa Cheng : Results
No full textStanding wok-adjacent, chef and cookbook author Theresa Cheng displays a dish made during the Chinese Cooking program, while another person eyes the demonstration table
[[alternative]]The Analysis of Master's Theses in Sport Management in Taiwan
No full text[[abstract]]The Analysis of Master’s Theses in Sport Management in Taiwan
Lin, Wen-Cheng
Advisor：Philip Cheng, Shao-Tung, Ph.D.
Abstract
The purposes of this study were to understand and analyze the contents and the status of the development of 398 master’s theses and their 26803 references in sport management during 1993-2003 in Taiwan. The Content Analysis was used as the study’s main research method, with the assistance of the Citation Analysis. The instrument “content analysis checklist of master’s theses in sport management in Taiwan” was used to collect data. The data was statistically analyzed in terms of Frequency Distribution and Percentage, Chi-square. The results showed as the followings：
1.The total number of master’s theses in sport management has been growing significantly since 1998. The total number of master’s theses in sport management in different areas has been in unbalanced distribution. There were six major universities playing the key roles in terms of sport management research.
2.The main three research topics of the master’s theses were Sport Marketing Management（Sponsorship included）, Sport Management, Organization and Leadership, Sport Leisure Management.
3.There was no significant correlation found among master’s theses in different years and research topics. The significant correlations were found between these master’s theses were correlations among research purposes, research areas, research instruments, and computerize statistical software.
4.There was no significant correlation found among master’s theses in different areas, research purposes, research areas, research instruments, and computerize statistical software. The significant correlations were found between these master’s theses and their respective research topics, and research instruments.
5.The quantity of references has been increasing. The languages of the references were mainly Chinese and English. Most of the references were published between the year of 1991 and 2003. The main types of the references were books and journals. The most cited English author was Chelladurai, P., and the Chinese counterpart was Ministry of Education（Taiwan）.
This study provides the research information and analysis of Master’s Theses in Sport Management in Taiwan during recent 10 years, and expects the increasing application of qualitative research method in sport management. It would be combined together between Sport Marketing Management and Sport Leisure Management to create benefit for organization, and it would be a future trend.
Key words：Content Analysis, sport management.
A Study on Luo Zhi Cheng\ue2s Historical narrative poems
No full textLuo Zhi Cheng is an important poet in the field of Taiwanese modern poetry, who is known for distinctive linguistic style and intense creative consciousness that are respected. Based on his powerful imagination and flourishing creativity as two primary advantages, through the mediation of poetry, prose, remarks, and commentaries, he maximally amplifies the implication of literature, and thereby composes himself and enriches the character. Distinguished from the majority of researchers focusing on Luo\ue2s lyric works, this study particularly found a writing context of \ue2avoidance of lyric sensibility\ue2 in Luo\ue2s poems, that is, his series of works historical themes in the form of long poems utilizing narrative skills to exhibit the remarkable consistency between the internality and the externality of the author.
\ue3\ue3This study conducted a comparative investigation of Luo\ue2s poetry work (The Book of Zhuzi) and prose works (Austral Court\ue2s Notandum and The Initiation of Civilization) to build a relatively more multi-faceted \ue2author\ue2s image of Luo Zhi Cheng\ue2 according to the writing of works of historical themes. Using the methodology of narratology, I departed from the internality of the text (the collection of poems) to identify how Luo forms the ideal spectrum of character by shaping historical persons; and meanwhile, I equally departed from the collections of prose to grasp the external information of the texts, and thereby clarified that Luo may treat \ue2writing, individual, and society\ue2 as a process of self-fulfillment. It is the two corresponding identities \ue2poet\ue2 and \ue2the intellectual\ue2 that are the mechanism of his constructing self-justification. Such investigation of the internality and the externality of text confirmed the complex relationships of the sustained \ue2opposition,\ue2 \ue2coexistence,\ue2 and \ue2conflict\ue2 between Luo and his works of historical themes
[[alternative]]The Effect of Wai Tan Kung Exercise on Energy Expenditure And Heart Rate Variability
No full text[[abstract]]The Effect of Wai Tan Kung Exercise on
Energy Expenditure And Heart Rate Variability
Graduate student: Cheng-Kun Wu
Advisor: Cheng-Chung Lin ,Ph.D.
Abstract
The purpose of the present study was to investigate the effect of long-term Wai Tan Kung exercise on heart rate (HR), energy expenditure, oxygen uptake (VO2), ventilation (VE), heart rate variability and blood pressure. Two different groups of older adults were recruited. One group subjects (n =16; 65.0 ± 4.2 yrs, 163.3 ± 7.3 cm, 63.3 ± 7.3 kg) had been participated at least 10 years of regular Wai Tan Kung exercise (long-term group, LTG), and the other (n = 16; 59.0 ± 3.7 yrs, 162.0 ± 3.9 cm, 65.7 ± 3.6 kg) had been participated as same exercise as LTG but less than one year (short-term group, STG). The results of this study showed that there were significant differences (p < .05) in rest systolic pressure, and HR, energy expenditure, VO2, VE, high frequency power (HFP) and low frequency power (LFP) during exercise between LTG and STG (p < .05). LTG subjects had a significant lower in rest heart rate and blood pressure (p < .05) than STG subjects, and the former also reached higher (p < .05) exercise intensities during exercise testing than the latter. Moreover, there were significant higher heart rate, VO2 and VE during exercise testing for LTG than STG, suggesting that LTG subjects had higher metabolic rate. Additionally, LTG had a higher HFP than STG, suggesting that there was a significant increase in parasympathetic division of autonomic nervous activity during exercise testing for LTG than STG, indicating LTG subjects may prevent from coronary artery disease and improve functions of the heart. It is concluded that older adults participate in regular long-term of Wai Tan Kung exercise have a positive effect on their cardiovascular fitness. Therefore, such kind of exercise may especially fit for older adults.
Key words: oxygen uptake (VO2), ventilation (VE), heart rate, heart rate variability, Wai Tan Kung exercise.
[[alternative]]The study for Master Cheng-Yen’s gratitude leadership and its educational practice.
No full text[[abstract]]The study for Master Cheng-Yen’s gratitude leadership and its educational practice.
Abstract
This thesis is based on personal experiences in education and admiration for Master Cheng-Yen’s Great Love for the world. Thus, this thesis aims at working out the theoretic system of Master Cheng-Yen’s Gratitude Leadership, including its nature and practice. Further, its contributions for educational leadership are approached.
In order to reach the above aim, critical analysis is used for clarifying the works by Master Cheng-Yen. In addition, a questionnaire and semi-structure interview questionnaire are designed for identifying the nature and practical approaches of Gratitude Leadership. It is by this way, Master Cheng-Yen’s theory and practice of Gratitude Leadership can be grasped which affords help for educational leadership, in terms of theory and practice in schools.
Finally, the results of this thesis are as follows:
a) Master Cheng-Yen’s Gratitude Leadership makes significant contribution for democratic education via purifying human heart and harmonizing the society;
b) it is helpful for promoting inner motivation of educational organization; and
c) it develops characteristics of creativity with non-power leadership style with effectiveness.
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