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1.
TANG Zhi-feng LV Fu-zai XIANG Zhan-qin 《浙江大学学报(A卷英文版)》2007,8(7):1059-1064
This paper presents two numerical realization of Preisach model by Density Function Method (DFM) and F Function Method (FFM) for a giant magnetostrictive actuator (GMA). Experiment and simulation showed that FFM is better than DFM for predicting precision of hysteresis loops. Lagrange bilinear interpolation algorithm is used in Preisach numerical realization to enhance prediction performance. A set of hysteresis loops and higher order reversal curves are predicted and experimentally verified. The good agreement between the measured and predicted curves shows that the classical Preisach model is effective for modelling the quasi-static hysteresis of the GMA. 相似文献
2.
a number of与the number of两个比较容易混淆的短语，尤其是当它们作主语时，其谓语的单复数形式很容易被弄错。要解开他们之间的疙瘩，其中的奥妙就在下面。 相似文献
3.
INTRODUCTIONInthispaperwewilldiscusssomeproblemsoninventoryreplenishmentpoliciesfordeteriorat ingitemswithshortagesinadecliningmarket.Replenishmentpoliciesofdeterioratingcommodi tieshavebeenaninterestingresearchtopicinin ventorymanagementsinthepast,anditwillre mainlikelythesameinthefuture.SinceGhareandSchrader (1963 )publishedthefirstpaperconsideringdeteriorationofinventory,manypa perspresentedvariousmodelswithdifferentas sumptionsonpatternsofdeteriorationwithorwithoutshortages.Allofthem… 相似文献
4.
Frédéric Guay Catherine Ratelle Simon Larose Robert J. Vallerand Frank Vitaro 《Contemporary educational psychology》2013
Does the perception of many close relationships as autonomy-supportive make students more motivated and competent? The goal of this study was to use latent class analysis (LCA) to compare the educational correlates of having one vs. several autonomy-supportive relationships. Participants were 1406 high school students (47% boys, 52% girls). LCA revealed three groups: Group 1 (17%) included students who perceived low autonomy support by their mother, father, and teacher; Group 2 (7%) included students who perceived low autonomy support by their father, but moderate autonomy support by their mother and teacher; and Group 3 (76%) included students who perceived all sources as moderately autonomy-supportive. Results of multiple comparisons suggest that more is not necessarily better: Students in Group 2, who perceived low autonomy support by fathers, reported equivalent autonomous (intrinsic and identified) and controlled (external and introjected) regulations and perceived competence to those of students in Group 3, who perceived all sources as moderately autonomy-supportive. One difference was that Group 3 showed better academic achievement than Group 2. Results are discussed in light of research on close relationships and self-determination theory (SDT). 相似文献
5.
邱学绍 《重庆大学学报(英文版)》2003,2(1)
~~Super number roots and factorizations for a kind of polynomial@邱学绍$Information and Computation Department, Zhengzhou Institute of Light Industry, Zhengzhou450002, P.R. China~~ 相似文献
6.
Hodges Tracey S. Wright Katherine Landau Roberts Kathryn L. Norman Rebecca R. Coleman Julianne 《Learning Environments Research》2019,22(3):427-441
Learning Environments Research - In this study, we examined students’ access to text, defined as the number of texts freely available to children in their classrooms. From 60 elementary... 相似文献
7.
Sedimentation tanks and clarifiers play a significant role in an active sludge system, and the efficiency of the whole system is closely related with the design and operation of the sedimentation tanks. This paper focuses on the sludge concentration in each cross-section of the sedimentation tank. We measured the sludge concentration to explore its distribution inside the tank, carried in-situ tests to research the fluid pattern and real operational rules of the sedimentation tank. We also used the computational fluid dynamics (CFD) software, PHOENICS 3.5, to simulate the solid-liquid two-phase fluid inside the tank and describe the sludge concentration distribution. The numerical results indicate obviously a sludge-water interface and a compression interface inside the sedimentation tank, a stratified sedimentary region with uniform concentration and a compression region with high concentration at the bottom of the tank. Although the simulated concentrations deviated slightly from those of in-situ tests, they were still acceptable for identifying the sludge interfaces and fluid pattern inside a sedimentation tank, which are important parameters for optimizing the tank size and improving the settling efficiency. 相似文献
8.
The methodology of 5-axis cutter selection to avert collision for free-form surface machining by flat-end cutters is presented.The combination of different cutters is adopt aiming at short machining time and high precision.The optimal small cutter is determined based on the geometric information of the points where a cutter most probably collide with the machined surface.Several larger cutters are slected to machine the surface in order to find the interference-free area.The difference of machining time for this area between the optimal small cutter and the large cutters is calculated.The functional relationship between the machining time and the radius of a cutter is established,by which the optimal number of cutters is obtained.The combination of cutters,which possesses the minimum overall machining time,is selected as the optimal cutter sizes.A case study has demonstrated the validity of the proposed methodology and algorithms. 相似文献
9.
Turner syndrome is a common genetic disorder associated with select deficits in executive functions, working memory and mathematics. In Study 1, we examined growth trajectories of skills in these areas, from grades 1 to 6, among girls with or without Turner syndrome. Rates of growth and performance levels at 6th grade, on an untimed math achievement test, did not suggest that girls with Turner syndrome have math learning difficulty (MLD). However, analyses did reveal lower efficiency on timed executive function tasks, among girls with Turner syndrome, who traded accuracy for speed under mild to moderate working memory demands. In Study 2 we compared numerical processing skills of 6th graders who had either Turner syndrome, MLD, low math achievement, or typical achievement in math. A numerical decomposition task revealed numerical processing deficits for the Turner syndrome and MLD groups, relative to typically achieving students. The relative difficulties in how numerical processing vs. working memory demands affected performance accuracy differed among groups, with the former demands leading to more performance difficulties in the Turner syndrome group. Our findings support the notion that girls with Turner syndrome recruit different strategies than their peers during allegedly basic numerical processing, that numerical processing deficits vs. executive function deficits underlie their difficulties with mathematics, and that math difficulties among these girls may not be apparent on untimed tests. These finding have implications for a possible manifestation of MLD. 相似文献
10.
Xia Li Ye Sun Arthur J. Baroody David Purpura 《European Journal of Psychology of Education - EJPE》2013,28(4):1525-1542
Recent research has found that linguistic cues may affect children's number word acquisition. Two studies were undertaken to evaluate the use of singular/plural markings and small number words in Chinese and English and its effect on children's number concepts. The first study utilized the CHILDES data and investigated how singular/plural markings and number words of "one," "two," and "three" are used in Chinese and compared it with that of English. The second study entailed testing twenty-four 2.4- to 3.3-year-old Chinese- and English-speaking children on number identification tasks. Results show that the English-speaking children performed significantly better than Chinese-speaking children in identifying "two," "three," and "four" as referents for collections of multiple items but not in identifying those number words as referents for specific pluralities. Additionally, the results show that English-speaking children were more inclined to count when quantifying small number sets than Chinese-speaking children. 相似文献
11.
Preschoolers’ conceptual understanding and procedural skills were examined so as to explore the role of number‐words and concept–procedure interactions in their additional knowledge. Eighteen three‐ to four‐year‐olds and 24 four‐ to five‐year‐olds judged commutativity and associativity principles and solved two‐term problems involving number words and unknown numbers. The older preschoolers outperformed younger preschoolers in judging concepts involving unknown numbers and children made more accurate commutativity than associativity judgements. Children with conceptual profiles indicating a strong understanding of concepts applied to unknown numbers were more accurate at solving number‐word problems than those with a poor conceptual understanding. The findings suggest that an important mathematical development during the preschool years may be learning to appreciate addition concepts as general principles that apply when exact numbers are unknown. 相似文献
12.
Children's intuitive understanding of numbers begins early in life, and their numbers-related knowledge influences instructors’ teaching practices. The number zero is more difficult to teach and learn than other numbers. The purpose of this study was to investigate how preschool teachers perceive the number zero and design their teaching practices for it. The participants in this case study were selected through convenience sampling. The findings indicated that the majority of the participating preschool teachers perceived the number zero as a symbol and considered children's age while developing teaching practices. 相似文献
13.
fixation rate and color fastness,but the Lanasol type of wool fiber used reactive dye is not so applicable to dye the soybean protein fiber.0针织工业Knittin 相似文献
14.
Andrew T. Knudsen 《Paedagogica Historica: International Journal of the History of Education》2016,52(5):507-524
AbstractWhen historians discuss the impact of examinations on elementary education in mid-Victorian England and Wales they typically focus on the Revised Code of 1862. The Revised Code is famous for instituting a policy of “payment-by-results” for teachers in state-supported voluntary schools. “Payment-by-results” made government grants to schools – and, by extension, for teachers’ salaries – contingent upon student attendance and pass rates in reading, writing and arithmetic. As this article emphasises, however, “payment-by-results” was not the first, or even the most significant, instance in which competitive examination was used by the state as an instrument for establishing the pedagogical fitness and salaries of teachers. Less often explored by historians is the formative role that state-mandated competitive examinations for teachers played in developing a professionally aspirant body of schoolteachers and, consequently, the schoolteachers’ later role in developing competitive examination as a broad-scale national accreditation apparatus. But while the use of competitive examinations came to shape modern British academic and professional life in fundamental ways, the strengthening effects that they had for certain occupations and institutions, such as physicians, civil servants and middle-class secondary schools, were in fact ultimately denied to state teachers and the elementary education sector generally. With the introduction of “payment-by-results” in 1862, competitive examinations were converted into an instrument that weakened rather than strengthened teachers’ professional identity and policy influence. This article explains how the nineteenth-century English state structured examinations and examination results to manipulate the professional status of teachers in order to suit state priorities during different stages of national development. This historical narrative is framed in reference to present-day examination-based reforms of teacher compensation systems such as performance-related-pay and value-added modelling. 相似文献
15.
ThisstoryisaboutfourFloridafirefightersnamedEverybody，Somebody，Any－bodyandNobody．Therewasanimportantjobtobedone．Everybodywasaskedtodoit．EverybodywassurethatSome－bodywoulddoit．Anybodycouldhavedoneit．ButNobodydidit．SomebodygotangrybecauseitwasEverybody＇sjob．Ev－erybodythoughtAnybodycoulddoit．NobodyrealizedthatEv－erybodywouldn＇tdoit．Itend－edupthatEverybodyblamedSomebody，whenactuallyNo－bodyblamedAnybody．参考译文：这个故事讲的是佛罗里达州的四名消防队员，他们的名字分别是… 相似文献
16.
This story is about four Florida fire fighters named Everybody, Somebody, Anybody and Nobody. There was an important job to be done. Everybody was asked to do it. Everybody was sure that Somebody would do 相似文献
17.
英语中的连词是一种虚词,在句子中不单独用作句子成分。连词按其性质可分为并列连词和从属连词。and,but,so,or就是大家所熟知的并列连词,在小学课文中接触过,也学习过。今天在这里简单地归纳总结。下面请四位连词先生作个自我介绍吧。 相似文献
18.
We used both student interviews and diagnostic testing to reveal students’ misconceptions about number representations in computing systems. This article reveals that students who have passed an undergraduate level computer organization course still possess surprising misconceptions about positional notations, two's complement representation, and overflow. Contrary to common opinion, these misconceptions are widespread and reveal the need for instruction that specifically targets these misconceptions. In addition, these misconceptions will serve as the basis for the creation of a standard assessment tool called the digital logic concept inventory. This concept inventory will provide a rigorous and quantitative metric to assess the effectiveness of new teaching methods. 相似文献
19.
Phillip D. Tomporowski Catherine L. Davis Patricia H. Miller Jack A. Naglieri 《Educational Psychology Review》2008,20(2):111-131
Studies that examine the effects of exercise on children’s intelligence, cognition, or academic achievement were reviewed
and results were discussed in light of (a) contemporary cognitive theory development directed toward exercise, (b) recent
research demonstrating the salutary effects of exercise on adults’ cognitive functioning, and (c) studies conducted with animals
that have linked physical activity to changes in neurological development and behavior. Similar to adults, exercise facilitates
children’s executive function (i.e., processes required to select, organize, and properly initiate goal-directed actions).
Exercise may prove to be a simple, yet important, method of enhancing those aspects of children’s mental functioning central
to cognitive development.
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| Phillip D. TomporowskiEmail: |
20.
1.Mr Yang is rich______he is not happy.2.It's cold,_____Miss Li will close the window.3.It is usually warm_____wet in spring. 相似文献