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81.
Novel high torque bearingless two-sided rotary ultrasonic motor 总被引:3,自引:0,他引:3
LI Xia CHEN Wei-shan XIE Tao LIU Jun-kao 《浙江大学学报(A卷英文版)》2007,8(5):786-792
Applications are limited at present because the currently available ultrasonic motors (USMs) do not provide suffi-ciently high torque and power. The conventional travelling-wave USM needs the bearing to support, which required lubricant. To solve the above problem, a bearingless travelling-wave USM is designed. First, a novel structure of the two-sided USM consisting of a two-sided teeth stator and two disk-type rotors is designed. And the excitation principle of the two-sided travelling-wave USM is analyzed. Then, using ANSYS software, we set up the model of the stator to predict the excitation frequency and modal response of the stator. The shape of the vibration mode was obtained. Last, the load characteristics of the USM are measured using ex-perimental method. The maximum stall torque and the no-load speed were obtained. The results showed that the characteristics of the two-sided USM are better than those of the conventional one-sided USM. 相似文献
82.
Joseph P. Allen Meghan A. Costello Amanda F. Hellwig Corey Pettit Jessica A. Stern Bert N. Uchino 《Child development》2023,94(6):1610-1624
Adolescent success providing satisfying support in response to a close friend's call in a caregiving task was examined as a potentially fundamental developmental competence likely to predict future social functioning, adult caregiving security, and physical health. Adolescents (86 males, 98 females; 58% White, 29% African American, 8% mixed race/ethnicity, 5% other) were followed from ages 13 to 33 (1998–2021) using multiple methods and reporters. Early caregiving success was found to predict greater self- and partner-reported caregiving security, lower negativity in adult relationships, and higher adult vagal tone. Results are interpreted as advancing our understanding beyond simply recognizing that adolescent friendships have long-term import, to now identifying specific capacities within friendships that are linked to longer-term outcomes. 相似文献
83.
You Guo Jiang 《Frontiers of Education in China》2013,8(2):326-329
Contemporary international higher education scholarship tends to focus on the global financial crisis,on massification,privatization,cross-border education,university ranking,and student mobility.However,few studies deal with the development of liberal arts programs around the world and they are often related to Western systems of higher education or that of the US,where liberal arts education has long been seen as a fundamental issue.Comparative studies,however,could help scholars to become aware of critical trends and reforms,also the impact they might have on a global society. 相似文献
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85.
A paired-associate memory task with pictures and words as items was used to categorize fourth graders into four learner types: HH, high picture-high word; HL, high picture-low word; LH, low picture-high word; LL, low picture-low word. Some children in each classification read prose passages with picture adjunct aids; other children read the passages without adjunct aids. Although free recall for the prose passage yielded inconclusive data, a constructed response test for facts in the prose passages revealed significant Aptitude × Treatment interactions, such that poor paired-associate learners (i.e., LLs) profited more than did good paired-associate learners (i.e., HHs) from picture aids on the prose task. The children's standardized reading scores were positively related to memory performance, but good and poor readers did not differ in their ability to profit from picture aids. It was suggested that less-strategic learners, such as those who perform poorly on paired-associate tasks, are more likely to be helped by externally provided mediational aids, while more-strategic learners are more likely to be helped by instructions to generate their own mediational aids. 相似文献
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88.
Mechanisms of the relation between perinatal problems, early childhood illness, and psychopathology in late childhood and adolescence 总被引:6,自引:0,他引:6
Data on perinatal and early childhood somatic and psychological risk factors of a random sample of children were gathered in early to middle childhood and employed to examine the long-term risk of emotional and behavioral problems of late childhood and adolescence. 3 issues were addressed: First, can syndromic specificity of such effects be identified on scaled and diagnostic measures of syndromes? Second, are these effects attributable to excess risk of low-income children for both perinatal and later childhood problems? Third, are the intervening mechanisms identifiable as intellectual impairment, vulnerability to poor health, poor maternal caretaking, maternal rejection, or maternal stress associated with marital problems? Findings indicated that elevated risk was present for all syndromes, both at the scale level and at the diagnostic level. None of the examined intervening mechanisms fully accounted for the effects of early risks. 相似文献
89.
Genetic and environmental origins of individual differences in masculine and feminine personality attributes were investigated in a sample of 38 monozygotic and 32 dizygotic twin pairs (total N = 140) during pre- and early adolescence. Self-report measures of both masculine and feminine characteristics were obtained for each child using 2 standardized instruments: the Children's Personality Attributes Questionnaire (CPAQ) and the Adolescent Self-Perception Inventory (ASPI). Multivariate biometrical analyses revealed significant genetic influences in all measures, accounting for 20%-48% of the observed variation in each. Environmental influences, which explained the remaining 52%-80% of variance in masculinity and femininity, were apparently specific to each individual and not shared by members of the same twin pair. The results underscore the importance of considering both genetic and environmental factors in gender-role development, particularly in studies of family resemblance. 相似文献
90.
Cultural interpretations of the visual meaning of icons and images used in North American web design
Eliot Knight Charlotte N. Gunawardena Cengiz Hakan Aydin 《Educational Media International》2013,50(1):17-35
This study examines cross‐cultural interpretations of icons and images drawn from US academic websites. Participants from Morocco, Sri Lanka, Turkey, and the USA responded to an online questionnaire containing 18 icons and images representing online functions and information types common on US academic websites. Participants supplied meanings for icons and images and selected a preferred image to represent each of four specific online functions. From three images of professors, participants chose one with whom they would prefer to study. Data were collected at the University of New Mexico, USA; in Internet cafes in the Middle Atlas region and at Al‐Akhawayn University, Morocco; the Open University of Sri Lanka in Nawala, Nugegoda; and at Anadolu University, Turkey. A qualitative analysis examines participants' perspectives and preferences for specific representations and identifies cultural themes in relation to Hofstede's dimensions. Implications for the design of images for cross‐cultural users are discussed. L'interprétation culturelle de la signification visuelle des icônes et images utilisées dans la conception de sites Web en Amérique du Nord La présente étude porte sur les interprétations transculturelles des icônes et des images extraites de sites universitaires américains. Des participants venus du Maroc,du Sri Lanka, de Turquie et des Etats Unis, ont répondu à un questionnaire en ligne contenant 18 icônes et images représentant des fonctions en ligne et des modes d'information que l'on trouve couramment sur les sites universitaires américains. Ces participants ont attribué des significations aux icônes et images et sélectionné l'image qu'ils (elles) préféraient pour représenter chacune des quatre fonctions en ligne proposées. A partir de trois images de professeurs,les participants en ont choisi une, celle avec qui ils (elles) préféreraient étudier. Une étude quantitative examine les perspectives des participants et leurs préférences pour une représentation donnée et elle identifie les thèmes culturels par rapport aux dimensions de Hofstede. On étudie les conséquences que cela peut avoir pour la conception d'images destinées à des utilisateurs interculturels. Kulturelle Interpretationen der visuellen Bedeutung der Symbole und Bilder, die in Nordamerika Web‐Design benutzt werden Diese Studie untersucht cross‐kulturelle Interpretationen von Symbolen und Bildern, die in akademischen US‐Websites benutzt werden. Teilnehmer aus Marokko, Sri Lanka, der Türkei und den USA bearbeiteten einen Online‐Fragebogen mit 18 Ikonen und Bildern, die Online‐Funktionen und – Informationen auf akademischen US‐Websites gemeinsamen sind. Die Teilnehmer benannten angenommene Bedeutungen der Symbole und Bilder und wählten ein bevorzugtes Bild für jede der vier spezifischen Online‐Funktionen aus. Aus drei Bildern von Professoren wählten die Teilnehmer eines aus, das denjenigen zeigen sollte, mit dem sie es vorziehen würden zu studieren. Eine qualitative Analyse untersucht Perspektiven und Präferenzen der Teilnehmer für bestimmte Vertretungen und Identitäten kultureller Themen in Bezug auf die von Hofstede aufgestellten Dimensionen. Auswirkungen auf die Gestaltung von Bildern für cross‐kulturelle Nutzer werden diskutiert. La interpretación cultural del significado visual de iconos y imagenes utilizados en el diseño de sitios Web en América del Norte Este artículo examina las interpretaciones transculturales de iconos y imágenes procedentes de sitios académicos de los Estados Unidos. Participantes de Marruecos, Sri Lanka, Turquía y los EUA respondierón a un cuestionario en línea conteniendo 18 iconos y imágenes que representan funciones en línea y tipos de información que se encuentran frecuentemente en los sitios académicos de los EUA. Los participantes propusieron significados para los iconos y imágenes y seleccionarón la imágen que les parecía más idónea para representar cada una de cuatros funciones en línea específicas. Entre tres imágenes de profesores, los participantes seleccionarón una, la de la persona con quien les gustaría estudiar. Un análisis cualitativo examina las perspectivas y preferencias de los participantes para tal o tal representación específica y al mismo tiempo se analiza temas culturales en relación con las dimensiones de Hofstede. Se analizan también las consecuencias que esto conlleva para el diseño de imágenes destinadas a usuarios transculturales. 相似文献