1,532 research outputs found

    A study of Al1-xInxN growth by reflection high-energy electron diffraction-incorporation of cation atoms during molecular-beam epitaxy

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    Molecular-beam epitaxy of Al1-x Inx N alloys with different indium (In) contents, x, were studied by in situ reflection high-energy electron diffraction (RHEED). Growth rates of the alloys were measured by the RHEED intensity oscillations for different source flux conditions, while the lattice parameters were derived from the diffraction patterns. It was found that under the excess nitrogen growth regime, incorporation of aluminum was complete whereas incorporation of In atoms was incomplete even at temperatures below 400 °C. © 2008 American Institute of Physics.published_or_final_versio

    浅析公路景观设计与评价

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    Author name used in this publication: SHI Wen-zhongAuthor name used in this publication: 贺志勇Author name used in this publication: 张肖宁2002-2003 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    A Double-Voltage-Controlled Effective Thermal Conductivity Model of Graphene for Thermoelectric Cooling

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    © 1963-2012 IEEE. Graphene provides a new opportunity for thermoelectric study based on its unique heat transfer behavior controllable by a gate voltage. In this paper, an effective thermal conductivity model of graphene for thermoelectric cooling is proposed. The model is based on a double-voltage-control mechanism. According to the law of Fourier heat conduction, an effective thermal conductivity model of the proposed thermoelectric cooling device is derived taking a tunable external voltage into account. Then, a gate voltage is used which can change graphene's thermoelectric characteristics. To verify the correctness and effectiveness of the proposed model, a circuit simulation model using HSPICE is built based on the thermoelectric duality. The simulation results from HSPICE and the calculated results from the mathematic model show good agreements with each other. This paper provides a novel precisely controlling method for thermoelectric cooling

    Molecular-beam epitaxy of AlInN: An effect of source flux and temperature on indium atom incorporation in alloys

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    Growth of AlInN alloys by molecular-beam epitaxy is studied by reflection high-energy electron diffraction, where in-plane lattice constant and specular beam intensity oscillations are recorded for information of lattice misfit and growth rate as a function of source flux and temperature. An unexpected dependence of alloy growth rate on indium flux is observed, which reflects the specific incorporation kinetics of indium in the alloy. © 2010 American Institute of Physics.published_or_final_versio

    Clustering of Multilevel Factors Among Children and Adolescents:Associations With Health-Related Physical Fitness

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    BACKGROUND: To identify the clustering characteristics of individual-, family-, and school-level factors, and examine their associations with health-related physical fitness. METHODS: A total of 145,893 Chinese children and adolescents aged 9-18 years participated in this cross-sectional study. The 2-step cluster analysis was conducted to identify clusters among individual-, family-, and school-level factors. Physical fitness indicator was calculated through sex- and age-specific z scores of forced vital capacity, standing long jump, sit-and-reach flexibility, body muscle strength, endurance running, and body mass index. RESULTS: Three, 3, and 5 clusters were automatically identified at individual, family, and school levels, respectively. Students with low physical fitness indicator were more likely to be in the "longest sedentary time and skipping breakfast" cluster (odds ratio [OR] = 1.18; 95% confidence interval [CI], 1.12-1.24), and "physical inactivity and insufficient protein consumption" cluster (OR = 1.07; 95% CI, 1.02-1.12) at individual level, the "single children and high parental education level" cluster (OR = 1.15; 95% CI, 1.10-1.21), and "no physical activity support and preference" cluster (OR = 1.30; 95% CI, 1.25-1.36) at family level, and the "physical education occupied" cluster (OR = 1.06; 95% CI, 1.01-1.11), and "insufficient physical education frequency" cluster (OR = 1.16; 95% CI, 1.08-1.24) at school level. Girls were more vulnerable to individual- and school-level clusters, while boys were more susceptible to family clusters; the younger students were more sensitive to school clusters, and the older students were more susceptible to family clusters (P-interaction &lt; .05). CONCLUSIONS: This study confirmed different clusters at multilevel factors and proved their associations with health-related physical fitness, thus providing new perspective for developing targeted interventions.</p

    Clustering of Multilevel Factors Among Children and Adolescents:Associations With Health-Related Physical Fitness

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    BACKGROUND: To identify the clustering characteristics of individual-, family-, and school-level factors, and examine their associations with health-related physical fitness. METHODS: A total of 145,893 Chinese children and adolescents aged 9-18 years participated in this cross-sectional study. The 2-step cluster analysis was conducted to identify clusters among individual-, family-, and school-level factors. Physical fitness indicator was calculated through sex- and age-specific z scores of forced vital capacity, standing long jump, sit-and-reach flexibility, body muscle strength, endurance running, and body mass index. RESULTS: Three, 3, and 5 clusters were automatically identified at individual, family, and school levels, respectively. Students with low physical fitness indicator were more likely to be in the "longest sedentary time and skipping breakfast" cluster (odds ratio [OR] = 1.18; 95% confidence interval [CI], 1.12-1.24), and "physical inactivity and insufficient protein consumption" cluster (OR = 1.07; 95% CI, 1.02-1.12) at individual level, the "single children and high parental education level" cluster (OR = 1.15; 95% CI, 1.10-1.21), and "no physical activity support and preference" cluster (OR = 1.30; 95% CI, 1.25-1.36) at family level, and the "physical education occupied" cluster (OR = 1.06; 95% CI, 1.01-1.11), and "insufficient physical education frequency" cluster (OR = 1.16; 95% CI, 1.08-1.24) at school level. Girls were more vulnerable to individual- and school-level clusters, while boys were more susceptible to family clusters; the younger students were more sensitive to school clusters, and the older students were more susceptible to family clusters (P-interaction &lt; .05). CONCLUSIONS: This study confirmed different clusters at multilevel factors and proved their associations with health-related physical fitness, thus providing new perspective for developing targeted interventions.</p

    Male germ cell-specific protein Trs4 binds to multiple proteins

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    Temperature-related sequence 4 (Trs4) has been identified as a testis-specific gene with expression sensitive to the abdominal temperature changes induced by artificial cryptorchidism. In murine testes, Trs4 mRNA was detected in round spermatids and its protein was localized mainly in the elongating spermatids as well as in the acrosomes and tails of mature spermatozoa. Using a yeast two-hybrid screening system, we identified Rshl-2, Gstmu1, and Ddc8 as putative binding partners of the Trs4 protein in mouse testes. Their interactions were confirmed by in vivo and in vitro binding assays. Further studies demonstrated that Ddc8, a newly identified gene with unknown functions, displayed a similar expression pattern with Trs4 in mouse testes. In particular, Trs4, Ddc8, and Rshl-2 proteins were co-localized to the tails of mature spermatozoa. These results suggested that Trs4 might be involved in diverse processes of spermiogenesis and/or fertilization through interactions with its multiple binding partners. © 2009 Elsevier Inc.postprin

    Finite Element Modelling and Damage Detection of Seam Weld

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    © Springer Nature Singapore Pte Ltd 2020. Seam welds are widely used in assembled structures for connecting components. However, the dynamic effects of a seam weld are often difficult to characterise in numerical models for several reasons: (1) it is often not wise to build a fine mesh on the seam line which will add considerable computational cost for a structure with many welds, (2) the mechanical properties of weld materials are not well known; (3) sometimes some geometric information about welds is not known beforehand. In this work, the finite element model of a welding connection part is developed by employing CSEAM element in NASTRAN and its feasibility for representing a seam weld is investigated. Based on this result, a damage detection method by updating the properties of the built CSEAM elements is also proposed for welding quality assurance. The damage takes the form of a gap in the weld which causes a sharp change of model strain energy at the edges of the gap for certain vibration modes. Specifically, the model strain energy shape is used as the objective function. A Kriging model is introduced for efficiency and simulation of a T-shaped welded plate structure to demonstrate the effectiveness of this method
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