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1.
对称配筋小偏心受压构件的截面设计 总被引:4,自引:1,他引:3
对小偏心受压构件在对称配筋情况下的截面配筋计算,提出用最佳一次逼近多项式简化基本公式,直接按二次方程求解ξ的近似方法,具有精度高,相对误差小,计算方便等优点,可供工程设计人员参考。 相似文献
2.
In its policy rationale for evidence-based practice in psychology (EBPP), the APA Presidential Task Force on Evidence-Based Practice (see record 2006-05893-001) claims to have constituted itself with "scientists and practitioners from a wide range of perspectives and traditions, reflecting the diverse perspectives within the field" (p. 273). We applaud this attention to diversity but contend that an entire perspective of the debate was omitted in the Task Force's newly approved policy and its underlying report. The failure to consider a philosophy of science perspective led the Task Force to make a number of epistemological assumptions that are not based on evidence or rationale and that thus violate the very spirit of evidence-based decision making. In this comment, we reveal a few of these assumptions and discuss their detrimental consequences. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
Michael V. Antony 《Minds and Machines》1991,1(3):321-341
Fodor and Pylyshyn (1988) have argued that the cognitive architecture is not Connectionist. Their argument takes the following form: (1) the cognitive architecture is Classical; (2) Classicalism and Connectionism are incompatible; (3) therefore the cognitive architecture is not Connectionist. In this essay I argue that Fodor and Pylyshyn's defenses of (1) and (2) are inadequate. Their argument for (1), based on their claim that Classicalism best explains the systematicity of cognitive capacities, is an invalid instance of inference to the best explanation. And their argument for (2) turns out to be question-begging. The upshot is that, while Fodor and Pylyshyn have presented Connectionists with the important empirical challenge of explaining systematicity, they have failed to provide sufficient reason for inferring that the cognitive architecture is Classical and not Connectionist. 相似文献
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本文利用最优回归设计“310”方案,研究了黑土地甜菜 Zn、K_2O、B的效果及合理施用问题。得出甜菜块根产量、含糖、产糖量、灰分 K 和有害 N 与 ZnK_2O、B 肥回归关系显著的回归模型,分析了 Zn、K_2O、B 对上述五个指标的效应,明确了 Zn 是影响各项指标的主要因子,并采用频率筛选法,提出了兼顾上述五项指标的优质高产施肥措施。 相似文献
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C. Llopis F. Revents L. Batet C. Pretel I. Sol 《Nuclear Engineering and Design》2007,237(18):2014-2023
The Technical University of Catalonia (UPC) has been jointly working with the Asociación Nuclear Ascó-Vandellòs (ANAV) for a number of years in order to establish, qualify and use best estimate (BE) models for the reactors under the control of ANAV. ANAV is the consortium that is responsible for operation of the Ascó and Vandellòs-II reactors. The reactors are Westinghouse-design three-loop PWRs with an approximate electrical power of 1000 MW. The existing integral plant models for each plant are currently used for many different purposes among which are support of plant operation and control. Quite a number of studies have been done in order to improve both safety and plant competitiveness. Most of these dynamic analyses were carried out in relation to transients starting at nominal full power or at least, very close to full power. This paper develops a specific use of the Vandellòs-II plant model for operation and control support at low power involving new ranges of system actuation parameters. It also examines scenarios that are somewhat different from those typically analysed. The study starts showing the results of an assessment case, which is a start-up test and provides some additional qualification, and subsequently attempts to establish calculations to support both an improvement in feed water controls and to set up operating recommendations for low-load manual operation of feed water turbo-pump. Both results hopefully, will produce an outcome, which leads to an improvement in safety and reduces reactor trip probability. 相似文献
8.
腐殖(植)酸(Humic Acid,以下简称HA)是天然有机化合物。在农业应用上十分广泛,主要有土壤改良剂、肥料、农药、植物生长剂、兽药、饲料添加剂、水产养殖剂等产品。从狭义的角度说,食品生产源头指土、水、肥、药、种等主要生产环节的硬条件。HA与食品生产源头诸要素之问关系密切。HA与土壤:土壤是种植业依赖的生命基础;HA是土壤有机质中的重要组成部分,也是最活跃的部分。HA与水:水是生命之源;HA在水生体系中普遍存在,是转运大多数生命必需物质甚至毒性物质的一种非常好的工具。HA与肥料:肥料是植物的粮食;HA在改良肥料、增加肥效、提高肥料利用率、协调各种营养等方面具有非常重要的作用。HA与农药:农药是植物的保护伞;HA具有提高农药药效、降低农药毒性、保护农业环境的基本条件。HA与种苗:种苗不好,作物不保;HA是孵化种苗的“保育剂”。除土、水、肥、药、种外,HA因其具有生理活性特征,而与种植业相关的诸多因素均有良好的协同作用。在此基础上,由HA开发的农用产品,涉足改土、活水、制肥、制药、种苗处理及其他衍生制剂等6大类产品,足以构筑起立体农业的防护体系,也是构筑食品源头安全的最佳选择。 相似文献
9.
Selection of strategies that help reduce riverine inputs requires numerical models that accurately quantify hydrologic processes. While numerous models exist, information on how to evaluate and select the most robust models is limited. Toward this end, we developed a comprehensive approach that helps evaluate watershed models in their ability to simulate flow regimes critical to downstream ecosystem services. We demonstrated the method using the Soil and Water Assessment Tool (SWAT), the Hydrological Simulation Program–FORTRAN (HSPF) model, and Distributed Large Basin Runoff Model (DLBRM) applied to the Maumee River Basin (USA). The approach helped in identifying that each model simulated flows within acceptable ranges. However, each was limited in its ability to simulate flows triggered by extreme weather events, owing to algorithms not being optimized for such events and mismatched physiographic watershed conditions. Ultimately, we found HSPF to best predict river flow, whereas SWAT offered the most flexibility for evaluating agricultural management practices. 相似文献
10.
李曼 《武汉纺织工学院学报》2009,(2):12-16
随着办研究氧化亚铁硫杆菌结果表明,最佳培养温度为30℃左右,最佳生长pH为2.0~2.5,最佳生长初始Fe2+浓为0115mol/L左右,在进行细菌培养时接种量取10%比较恰当。低pH值和高浓度Fe2+驯化后,在培养温度30℃、初始pH值1.5、初始Fe2+浓度25g/L条件下,氧化亚铁硫杆菌仍能保持一定的Fe2+氧化活性,6天Fe2+氧化率可达82.28%,Fe2+平均氧化速率达3.43g/L/d,pH值的变化是先上升后下降,最后稳定在1.81。 相似文献