30 research outputs found

    大台北地區國民中學電腦課程內涵之研究

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    [[abstract]]Abstract The main purposes of this study were to Investigate and analyze the degree of importance for the content of junior high school computer curriculum. According to the results of the research, the researcher set forth recommendations that concerning about the selection of content for the computer curriculum for schools and teachers to consider. This study made use of Delphi method to accomplish the research objectives. The researcher collected related documents and carried out an analytical investigation questionnaire. This questionnaire “The Content of Public Junior School Computer Curriculum,” carried out Delphi three times for the expert team. The expert team is consisted of 6 computer educational professors and 6 public junior high school computer teachers. The Mean, Median, and Quartile Deviation for the data obtained from the survey were used to assess the degree of importance for each question item as well as the circumstances of the centralization or dispersal of the opinions. The results obtained from the final questionnaire utilized the One Sample Test of Kolmogorov-Smironov for the testing in order to find out whether or not the experts’ and teachers’ viewpoints on each question item had significant variations. The research results are listed below: 1. Computer technology as already blended into everyday life. Understanding basic computer operations is a basic ability for our nation’s current generation in moving towards an information society. 2. After going through the Delphi questionnaire three times, there were finally only 11 chapters with 34 units that were comparatively suitable for the current stage of junior high school computer curriculum. The total class time was set at 96 hours. 3. For those 4 units, the computer development, the explanation of computer BIOS’s setting, standard unit, and databases, the content was relatively hard and not suitable for the current stage of junior high school instruction. It would be more suitable to be arranged for senior high school computer curriculum. Finally, in accordance with the research findings, recommendations will be addressed for the junior high schools, and the junior high schools’ teachers. Keywords: junior high school, computer curriculum, Content of Curriculum, Delphi

    [[alternative]]The Study of camphor sulfonic acid derivatives metal complex selective binding affinity to DNA

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    [[abstract]]This study utilize the cleavage activity of phage φX174 as the model DNA system to investigate the selectivity and affinity for a series camphor sulfonic acid derivatives [Cpd1: (C20H28N2O4), Cpd2: (C26H38N2O4), and Cpd3: (C27H26N4O4)] when complex with various metal ion. The cleavage activity is as follow: Zn2+ > Cu2+ >> Mn2+ ~ V4+ when complex with above series of camphor sulfonic acid derivatives as reveled from agarose electrophoresis experiment. Whereas the chemical shifting experiment in 1D 1H NMR (One-dimensional 1H nuclear magnetic resonance spectroscopy) show the all metal and camphor sulfonic acid derivatives would bind together. Whereas for the randomized sequence oligonucleotide, the AT-rich DNA sequence give better selectivity as forming stable 1:1 ratio complex such as: [d(CGAAATTTGCG)]2 > [d(CAGCTTG)]2 > [d(CCGG)]2 when investigated with CD (Circular dichroism) experiment.

    A review of impact loads on composite wind turbine blades: Impact threats and classification

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    A fiber-reinforced composite wind turbine blade (WTB) is exposed to numerous impact threats during its service life causing damages that can be detrimental to its structural integrity. Currently, impact loads are not considered during blade design, so high safety factors are introduced, which result in a conservative design. However, as wind turbine blades become stiffer and lighter and health monitoring systems become more sophisticated, the design process is shifting toward damage-tolerant approaches. The design philosophy accepts damages to the structure, but it also requires that the damaged blade still meet structural and functional requirements. This design procedure requires a comprehensive understanding of different impact threats and their characteristics, which is currently unavailable in the public domain. This paper is a first attempt to review the impact loads on composite wind turbine blades. The aim of the current paper is to (a) identify different sources of impact threats on wind turbine blades during different stages of their service life, (b) describe their qualitative (causes and vulnerable regions) as well as quantitative characteristics (size, mass, and velocity of impactor), and to (c) provide modeling guidelines by comparing these impact threats using five different criteria - (i) relative deformability of projectile and wind turbine blade, (ii) impact velocity, (iii) kinetic energy of impact, (iv) repeatability of impacts and (v) nature of the impact. The review paper will be of special interest to researchers working on wind turbine blades and will serve as a baseline report for designing damage-tolerant blades. Recommendations are also provided for future research.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Aerospace Manufacturing Technologie

    Reformation Capability of Short-Range Order and Their Medium-Range Connections Regulates Deformability of Bulk Metallic Glasses

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    Metallic glasses (MGs) typically have high yield strength while low ductility, and the latter is commonly considered as the Achilles&#39; heel of MGs. Elucidate the mechanism for such low ductility becomes the research focus of this field. With molecular level simulations, we show the degree of short-range order (SRO) of atomic structure for brittle Fe-based glass decreases dramatically during the stretch, while mild change occurs in ductile Zr-based glass. The reformation capability for SRO and their medium-range connections is found to be the primary characteristics to differentiate the deformability between the two metallic glasses. We suspect that, in addition to the strength of networks formed by SRO structure, the reformation capability to reform SRO networks also plays the key role in regulating the ductility in metallic glasses. Our study provides important insights into the understanding about the mechanisms accounting for ductility or brittleness of bulk metallic glasses.;Metallic glasses (MGs) typically have high yield strength while low ductility, and the latter is commonly considered as the Achilles&#39; heel of MGs. Elucidate the mechanism for such low ductility becomes the research focus of this field. With molecular level simulations, we show the degree of short-range order (SRO) of atomic structure for brittle Fe-based glass decreases dramatically during the stretch, while mild change occurs in ductile Zr-based glass. The reformation capability for SRO and their medium-range connections is found to be the primary characteristics to differentiate the deformability between the two metallic glasses. We suspect that, in addition to the strength of networks formed by SRO structure, the reformation capability to reform SRO networks also plays the key role in regulating the ductility in metallic glasses. Our study provides important insights into the understanding about the mechanisms accounting for ductility or brittleness of bulk metallic glasses.</p

    Numerical study on the deformation of soil stratum and vertical wells with gas hydrate dissociation

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    Gas hydrate (GH) dissociates owing to thermal injection or pressure reduction from the well in gas/oil or GH exploitation. GH dissociation leads to, for example, decreases in soil strength, engineering failures such as wellbore instabilities, and marine landslides. The FLAC3D software was used to analyze the deformation of the soil stratum and vertical wells with GH dissociation. The effects of Young's modulus, internal friction angle, cohesion of the GH layer after dissociation, and the thickness of the GH layer on the deformation of soils were studied. It is shown that the maximum displacement in the whole soil stratum occurs at the interface between the GH layer and the overlayer. The deformation of the soil stratum and wells increases with decreases in the modulus, internal friction angle, and cohesion after GH dissociation. The increase in thickness of the GH layer enlarges the deformation of the soil stratum and wells with GH dissociation. The hydrostatic pressure increases the settlement of the soil stratum, while constraining horizontal displacement. The interaction between two wells becomes significant when the affected zone around each well exceeds half the length of the GH dissociation zone

    Cellular entry of graphene nanosheets: The role of thickness, oxidation and surface adsorption

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    Coarse grained molecular dynamics simulations are conducted to study the interaction of graphene nanosheets with a lipid bilayer, focusing on the effects of graphene thicknesses (single/multi-layered graphene), oxidation and surface absorption by lipid molecules. The results show that a hydrophobic corner of graphene can pierce into the bilayer, while different oxidations of the nanosheets affect their final equilibrium configurations in the bilayer: lying across or within the hydrophobic core of the bilayer. The underlying mechanism is clarified by calculating the energy barrier for graphene piercing into the bilayer. Our studies provide fundamental guidance towards understanding how graphene enters cells, which is important for biomedical diagnostics and therapies, and for managing health impacts following occupational or environmental exposure

    Immobilization of lead by application of zeolite: Leaching column and rhizobox incubation studies

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    Application of zeolite can reduce lead (Pb) mobility in soil. Leaching columns and rhizobox incubation experiments were carried out to investigate the leaching processes and rhizosphere behavior of Pb in a Pb-contaminated soil amended with zeolite. Zeolite addition reduced Pb release from the contaminated soil as well as increasing leachate pH and decreasing the bioavailable Pb concentration. Leachate pH was not significantly different among different zeolite dose treatments at the same measurement time. Leaching of Pb from the treated soil was lower than that from the untreated soil for the first nine weeks but the trend was reversed for the final weeks of the study. The Pb concentration in the leachate did not appear to be sensitive to changes in pH. It was concluded that when a relatively low amount of zeolite was added (<20 mg kg(-1)), the cation exchange capacity was the dominant factor for regulating Pb leaching behavior. The DTPA extractable Pb in the rhizosphere was similar to 15% higher than that in the close-root and bulk soil. In addition, the amounts of DTPA extractable Pb in the rhizosphere soil not treated with zeolite were 10% and 16% higher than in the rhizosphere soil with 10 and 20 g kg-1 zeolite addition, respectively. It could be concluded that zeolite addition inhibits uptake of Pb by affecting rhizospheric behavior. (C) 2013 Elsevier B.V. All rights reserved.Application of zeolite can reduce lead (Pb) mobility in soil. Leaching columns and rhizobox incubation experiments were carried out to investigate the leaching processes and rhizosphere behavior of Pb in a Pb-contaminated soil amended with zeolite. Zeolite addition reduced Pb release from the contaminated soil as well as increasing leachate pH and decreasing the bioavailable Pb concentration. Leachate pH was not significantly different among different zeolite dose treatments at the same measurement time. Leaching of Pb from the treated soil was lower than that from the untreated soil for the first nine weeks but the trend was reversed for the final weeks of the study. The Pb concentration in the leachate did not appear to be sensitive to changes in pH. It was concluded that when a relatively low amount of zeolite was added (<20 mg kg(-1)), the cation exchange capacity was the dominant factor for regulating Pb leaching behavior. The DTPA extractable Pb in the rhizosphere was similar to 15% higher than that in the close-root and bulk soil. In addition, the amounts of DTPA extractable Pb in the rhizosphere soil not treated with zeolite were 10% and 16% higher than in the rhizosphere soil with 10 and 20 g kg-1 zeolite addition, respectively. It could be concluded that zeolite addition inhibits uptake of Pb by affecting rhizospheric behavior. (C) 2013 Elsevier B.V. All rights reserved

    Trend analysis for evaluating the consistency of Terra MODIS and SPOT VGT NDVI time series products in China

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    The Normalized Difference Vegetation Index (NDVI) is an important vegetation greenness indicator. Compared to the AVHRR GIMMS NDVI data, the availability of two datasets with 1 km spatial resolution, i.e., Terra MODIS (MOD13A3) monthly composite and SPOT Vegetation (VGT) 10-day composite NDVI, extends the application dimensions at spatial and temporal scales. An overlapping period of 12 years between the datasets now makes it possible to investigate the consistency of the two datasets. Linear regression trend analysis was performed to compare the two datasets in this study. The results show greater consistency in regression slopes in the semi-arid regions of northern China. Alternatively, the results show only slight changes in the Terra MODIS NDVI regression slope in most areas of southern China whereas the SPOT VGT NDVI shows positive changes over a large area. The corresponding regression slope values between Terra MODIS and SPOT VGT NDVI datasets from the linear fit had a fair agreement in the spatial dimension. However, larger positive and negative differences were observed at the junction of the three regions (East China, Central China, and North China). These differences can be partially explained by the positive standard deviation differences distributed over a large area at the junction of these three regions. This study demonstrated that Terra MODIS and SPOT VGT NDVI have a relatively robust basis for characterizing vegetation changes in annual NDVI in most of the semi-arid and arid regions in northern China.The Normalized Difference Vegetation Index (NDVI) is an important vegetation greenness indicator. Compared to the AVHRR GIMMS NDVI data, the availability of two datasets with 1 km spatial resolution, i.e., Terra MODIS (MOD13A3) monthly composite and SPOT Vegetation (VGT) 10-day composite NDVI, extends the application dimensions at spatial and temporal scales. An overlapping period of 12 years between the datasets now makes it possible to investigate the consistency of the two datasets. Linear regression trend analysis was performed to compare the two datasets in this study. The results show greater consistency in regression slopes in the semi-arid regions of northern China. Alternatively, the results show only slight changes in the Terra MODIS NDVI regression slope in most areas of southern China whereas the SPOT VGT NDVI shows positive changes over a large area. The corresponding regression slope values between Terra MODIS and SPOT VGT NDVI datasets from the linear fit had a fair agreement in the spatial dimension. However, larger positive and negative differences were observed at the junction of the three regions (East China, Central China, and North China). These differences can be partially explained by the positive standard deviation differences distributed over a large area at the junction of these three regions. This study demonstrated that Terra MODIS and SPOT VGT NDVI have a relatively robust basis for characterizing vegetation changes in annual NDVI in most of the semi-arid and arid regions in northern China

    PREVALENCE AND PREDICTORS OF POSTTRAUMATIC STRESS DISORDER AMONG CHINESE YOUTHS AFTER AN EARTHQUAKE

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    In the current study we investigated the prevalence and predictors of posttraumatic stress disorder (PTSD) among Chinese youths after an earthquake. A total of 753 middle school students participated in the survey and 99.5% of them were of Tibetan ethnicity. The University of California, Los Angeles PTSD Reaction Index was used to assess PTSD symptoms and a total of 101 participants were identified as probable PTSD cases. Independent predictors of PTSD included female sex, being injured, witnessing death, and derealization during the earthquake. Our results add to extant understanding of the impact of disasters on youth mental health, and carry implications for revising the current Criterion A2 of PTSD in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders
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