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101.
Christopher Higgins 《Canadian Metallurgical Quarterly》2004,9(6):599-605
Concrete filled grid bridge decks exhibit orthogonal elastic properties and significant two-way bending action enabling orthotropic plate theory to determine structural response for these elements. Current American Association of State Highway and Transportation Officials load and resistance factor design (LRFD) specifications employ an orthotropic plate model to predict live load moment in concrete filled grid bridge decks but provide no guidance for computing displacement, a potentially important serviceability consideration. This paper presents equations to approximate the maximum deflection in concrete filled grid bridge decks based on orthotropic plate theory, multiple patch loads, LRFD design truck and tandem load cases, the influence of multiple spans, and the two most common deck orientations. 相似文献
102.
103.
We report improvement of emission efficiency in polymer light-emitting devices (PLEDs) employing phosphorescent polymers. A hole-blocking layer was inserted between the emissive layer and the cathode to enhance recombination efficiency for the injected holes and electrons. Aluminum(III)bis(2-methyl-8-quinolinato)4-phenylphenolato (BAlq) was used for the hole-blocking layer. The resultant PLEDs exhibited significant improvement of emission efficiency. The respective external quantum efficiencies for red, green and blue PLEDs were 6.6, 11 and 6.9%. These values are very high compared with those based on conventional fluorescent polymers. 相似文献
104.
Almond preferences were produced by giving rats a mixture of almond and sucrose (Experiments 1-4) or saccharin (Experiment 4). A subsequent extinction procedure consisted of either repeated 2-bottle almond versus water tests (Experiment 1) or repeated exposure to almond alone (Experiments 2-4). The main independent variable was whether access to food following a session was given immediately, 30 min later, or 120 min later. No effect of extinction was found in any experiment. An important finding was that varying the delay until food access had no detectable effect. It was concluded that inadvertent flavor-food associations do not maintain preference for the flavor under extinction conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
105.
脆断事故的原因分析和预防措施 总被引:1,自引:0,他引:1
戚国胜 《南方冶金学院学报》2002,23(1):28-33
分析高强度材料和大型工程结构元件发生低应力脆性断裂的原因及条件,指出传统强度设计理论的局限性,从设计和工艺上提出防止发生低应力脆断事故的具体措施,给使用高强度材料和设计大型工程结构元件时提供参考。 相似文献
106.
Beck J. Gayle; Novy Diane M.; Diefenbach Gretchen J.; Stanley Melinda A.; Averill Patricia M.; Swann Alan C. 《Canadian Metallurgical Quarterly》2003,15(2):184
To examine affect and cognition in differentiating anxiety and depression, 83 older participants with generalized anxiety disorder completed the Cognitive Checklist (CCL) and the Positive and Negative Affect Schedule (PANAS). A 3-factor solution was found for the PANAS: positive affect (PA), anxiety and anger (Negative Affect 1 [NA-1]), and guilt and shame (Negative Affect 2 [NA-2]). A 2-factor structure was noted for the CCL. Correlations with anxiety and depression measures suggested that the CCL Depression (CCL-D) subscale showed stronger correlations with depression, whereas the CCL Anxiety subscale did not uniquely correlate with anxiety. The NA-1 subscale correlated positively with measures of depression and anxiety, whereas the PA subscale showed negative correlations. Hierarchical regression suggested that the CCL-D subscale was a significant predictor of self-reported depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
107.
The corrosion behavior of NiCrMo Alloy 625 (UNS N06625) has been characterized in a 10,000 h test conducted in hydrogenated water at 260 °C. The corrosion kinetics were observed to be parabolic, the parabolic rate constant being determined by chemical descaling to be 0.074 mg dm−2 h−1/2. Characterizations of the corrosion oxide layer via grazing incidence X-ray diffraction and X-ray photoelectron spectroscopy in combination with argon ion milling and target factor analysis, revealed the presence of two spinel oxide phases and significant amounts of recrystallized nickel. Based on the distribution of three oxidized alloying constituents (Ni, Cr, Fe) with respect to depth and oxidation state, it was concluded that: (a) corrosion occurs in a non-selective manner, but significant amounts of nickel(II) ions are released to the water, and (b) the spinel oxides exist as a chromite-rich inner layer (Ni0.7Fe0.3)(Cr0.8Fe0.2)2O4 underneath a coarser, ferrite-rich outer layer (Ni0.9Fe0.1)(Cr0.1Fe0.9)2O4. The trivalent cation distribution in each of these phases appears to represent a solvus in the immiscible NiCr2O4-NiFe2O4 binary. 相似文献
108.
单彤文 《中国海上油气(工程)》1995,(1)
容量系数法是用于项目初期平台上部设施估重的一种方法。本文介绍了容量系数法的理论基础、数据建立和估算实例,并分析了该法的应用条件和造成误差的原因。 相似文献
109.
本文介绍了降秩因子分析(RAFA)方法,它是从一个多组分混合物中直接定量计算其中某一组分,而不必知道其它组分的物种及含量的一种定量分析的数学方法。它适用于双线性的数据。本实验首先将荧光分光光度计与外接计算机相连,以获得样品的激发-发射矩阵(EEM),再用RAFA方法对蒽、萘、菲、芘、芴、(艹屈)六种标样的一至五组分的混合物进行定量分析,获得满意的结果。 相似文献
110.
一种可切削玻璃陶瓷的压痕断裂特性 总被引:4,自引:2,他引:2
将断裂韧性测试的压痕方法与压痕弯曲方法相结合,独立地分离出了压痕残余应力因子x,使其成为可测参量,并建立了压痕一压痕弯曲的断裂韧性测试方法.将这种方法应用于一种可切削玻璃陶瓷的测试,获得的K1c值为K1c=2.03MPa·m1/2,与单边切口法(SENB)获得的K1c值有较好的一致性.测得的残余应力因子X=0.093,符合Anstis经验公式的预测. 相似文献