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1.
Data from an anonymous survey of 3,690 adolescents were used to assess how much of the unique variance in adolescents' self-reported drug use was accounted for by number of parents in comparison to the adolescents' sex, age, social class, and peer drug use. Multiple regression revealed that the contribution of number of parents was small and nonsignificant compared to peer use, student age, parental occupation and remarriage, student sex, and parental unemployment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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Examined whether children with both academic and social skill deficiencies have higher levels of peer-nominated and self-ratings of depression than their more competent peers and whether depression levels can distinguish academically skilled children from socially skilled ones. Objective measures of academic and social competence classified 169 3rd–6th grade children as competent (above the median on both measures), incompetent (below on both), academically skilled (above only on academic competence), or socially skilled (above only on social competence). Children completed the Perceived Competence Scale for Children, Children's Depression Inventory, and a peer nomination inventory of depression. Results demonstrate information about academic and social competence best predicted Ss' depression. Peer-nominated and self-rated depression were highest among incompetent Ss and lowest among competent Ss. Peer-nominated happiness was higher among the socially skilled than among the academically skilled. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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Assigned 69 2nd–6th graders, identified as inconsistent because of extreme variability over baseline in math class work, to a home-note, family problem-solving, or control condition. Teachers scored Ss' math daily and sent home a Good-News Note with Ss in both intervention conditions when their daily means equaled or exceeded their baseline means. Ss in the family problem-solving condition wrote contingency contracts with their families, guided by a problem-solving board game, specifying consequences for receipt of Good-News Notes. Families in the home-note condition were instructed by letter to deliver favorable consequences on receipt of Good-News Notes. Compared to no treatment both forms of intervention significantly reduced class work scatter. Whereas Ss in the control and home-note conditions became less accurate during intervention, Ss in the family problem-solving condition maintained their accuracy. Only Ss in the family problem-solving condition demonstrated generalization to nonreinforced intervention probes. Involvement of the family meant that children produced high quality work even when their classmates' work dropped in quality and that they worked hard even when they expected no reward. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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Experiments on short term static compression of asphalt concrete specimens, differing in aggregate, compaction effort, bitumen percentage, size and type of loading, demonstrate a common pattern in the stress-strain relationship, identical to that long known for cement concrete and rock. Beyond the limit of linearity ‘swelling’ of asphalt concrete specimens is visible to the naked eye, analogously to cement concrete. When the friction between specimens and press platens is reduced, asphalt concrete undergoes a splitting type of failure, again like cement concrete. In the light of this similarity, the problem of asphalt concrete behaviour under short term compression is considered from the point of view adopted for cement concrete and rock. In the atrophy model the nonlinear behaviour of cement concrete in the ascending branch is ascribed to its degeneration due to the microcracking process. Applied to asphalt concrete, the model agrees well with experimental results.
Resume Les essais de compression statique à court terme qui ont été exécutés sur des éprouvettes de béton bitumineux présentant des différences de granulats, d'énergie de compactage, de pourcentage de bitume, de dimension et de type de charge démontrent un diagamme commun de la relation contrainte-déformation identique à celui qui est connu depuis longtemps pour le béton à base de ciment et les minéraux. Au-delà de la limite de linéarité, le ‘gonflement’ des éprouvettes de béton d'asphalte est visible à l'oeil nu comme pour le béton de ciment. Quand le frottement entre les éprouvettes et les plateaux de la presse est réduit, le béton d'asphalte subit une rupture par fendage, encore une fois comme le béton de ciment. On considère, à la lumière de cette similarité, le problème du comportement du béton d'asphalte sous compression à court terme à partir du point de vue adopté pour le béton à base de ciment et les minéraux. Dans le modèle atrophique, le comportement non linéaire du béton de ciment dans la branche ascendante est attribué à sa dégénérescence due au processus de microfissuration. Appliqué au béton d'asphalte, ce modèle concorde bien avec les résultats expérimentaux.
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Since the stress-strain diagram (SSD) indicates a number of distinct stages in the state of concrete, the stress-strain relationships cannot be encompassed within a single formula. It is shown that the peculiarities in the concrete behavior can be accounted for, if the widely-known fact of constancy of the instantaneous elastic modulus is taken to imply constancy of this modulus in general, the non-linearity being attributed to the atrophying effect of microcracking. It is shown that within the ascending branch of the SSD, the concrete under short-term load undergoes two stages: the elastic stage, and that of non-linear stress. For the first stage, the model is trivial; for the second, functions are derived describing the strain-dependence of the atrophying effect (hence, of the nominal stresses) — incorporating the elastic modulus, the peak strain and the elastic limit.

The presence of a Gaussian in the function of atrophy indicates stochasticity of the latter. In view of the constancy of the elastic modulus, and the impact of the atrophying effect on the live cross-section of the concrete, it follows that the specific stress and specific strength are a linear function of the strain right up to the strength point. A strength formula is also derived, relating the strength to the peak strain, the elastic limit and the initial elastic modulus.  相似文献   

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Examined the relationship between objective measures of childhood competence and behavior problems in 474 2nd–6th graders. Daily classwork measured the academic competence, and peer ratings measured social competence. Median splits formed 4 groups, with competent Ss highest and incompetent Ss lowest on the relatively independent dimensions of academic and social competence. Competent Ss excelled on attitudinal measures of a competent lifestyle and on the Harter Competence (HC) Scales. Teacher ratings on the Behavior Problem Checklist (BPC) attributed fewest problems to competent Ss. Conversely, incompetent Ss achieved the lowest HC and the highest BPC scores. Ss high on social competence and low on academic competence were distinguished by BPC conduct problems and nervousness. Peer nominations of depression on the Peer Nomination Inventory characterized all Ss low on social competence. (48 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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The ALL-1 gene positioned at 11q23 is directly involved in human acute leukemia either through a variety of chromosome translocations or by partial tandem duplications. ALL-1 is the human homologue of Drosophila trithorax which plays a critical role in maintaining proper spatial and temporal expression of the Antennapedia-bithorax homeotic genes determining the fruit fly's body pattern. Utilizing specific antibodies, we found that the ALL-1 protein distributes in cultured cells in a nuclear punctate pattern. Several chimeric ALL-1 proteins encoded by products of the chromosome translocations and expressed in transfected cells showed similar speckles. Dissection of the ALL-1 protein identified within its approximately 1,100 N-terminal residues three polypeptides directing nuclear localization and at least two main domains conferring distribution in dots. The latter spanned two short sequences conserved with TRITHORAX. Enforced nuclear expression of other domains of ALL-1, such as the PHD (zinc) fingers and the SET motif, resulted in uniform nonpunctate patterns. This indicates that positioning of the ALL-1 protein in subnuclear structures is mediated via interactions of ALL-1 N-terminal elements. We suggest that the speckles represent protein complexes which contain multiple copies of the ALL-1 protein and are positioned at ALL-1 target sites on the chromatin. Therefore, the role of the N-terminal portion of ALL-1 is to direct the protein to its target genes.  相似文献   
10.
In a noisy setting, 20 male and 20 female college students worked at anagrams and proofreading to reduce their sensitivity to the adverse effects of noise. Ss were randomly assigned before training to a perceived own-control- or no-control-over-noise condition and to a constant or increasing rate-of-exposure-to-noise condition. All Ss heard noxious noise punctuated by silence while they worked. Those who believed their rapid button pressing produced the silence improved significantly at proofreading but not at anagrams. Rate of exposure did not affect training. Conditions governing the contributions of perceived environment controlling responses to behavior rehearsal are discussed. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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