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《Planning》2021,(20)
<正>随着新课改的不断推进,高考作文中的材料作文也有了很大的变化,对学生的审题思路和核心素养提出了进一步的要求。材料作文的立意在很大程度上都会影响学生作文的得分,也能够有效考查学生的个人思想高度和核心素养水平,因此,教师要基于学生的核心素养对学生从立意到行文思路进行有效指导。在教学过程中着重强调作文立意的内涵和深度,提高学生的思想高度。 相似文献
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随着新常态下中国经济的发展与经济结构的优化,中国建筑业进入了存量竞争时代。分析了建筑企业在产业"寒冬"下面临的困境与挑战。以发达国家建筑承包商为例,提出了我国基建企业可以从有选择的多元化,适度的国际化,高度的价值链一体化、专业化、标准化以及资本市场有效运作几方面转型升级,以提高核心竞争力,从而穿越经济周期,保持收入和利润的持续增长。 相似文献
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随着世界经济一体化进程的加快,我国企业面临的市场竞争环境日益激烈和复杂,如何提高企业核心竞争力,全面增强企业的社会效益和经济效益,已经成为备受我国企业高度关注的重点向题.而有效的增强企业财会内控监督机制则是企业达成终极目标的重要保证.本文笔者对当前企业财会内控监督机制存在的问题作了深入分折,并针对这些问题提出了相应的对策. 相似文献
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提出梁板经济配筋率的核心范围 ,在核心范围以内 ,与经济配筋率的平均值相比较 ,无论是有效高(厚 )度 ,还是受拉钢筋的面积 ,都在正负 11%的合理范围之内 相似文献
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《交通与港航》编辑部 《城市公用事业》2018,(1)
党的十九大报告在建设现代化经济体系的战略部署中提出交通强国建设,这是以习近平同志为核心的党中央站在党和国家事业发展全局高度作出的战略部署,是新时代赋予交通运输行业的历史使命. 相似文献
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改革开放以来,社会主义经济的高度发展,带动了建筑业的发展.近年来,建筑业已经成为我国第二产业中的主体产业,随着建筑业企业的高度发展,建筑业不仅在我国的经济地位中有着不可撼动的地位,更是我国国民经济的主要支柱.因此对工程造价进行有效的管理和控制,可以更好的促进建筑业的持续稳步发展. 相似文献
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城市在国家社会、经济、人民生活中的地位越来越重要,随着全球经济一体化和和信息化的高度发展,城市的作用日益增强,国家之间,区域之间竞争更多地依赖城市间的竞争,世界各国已将城市发展、城市竞争力提高作为核心发展战略。 相似文献
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在沙漠地带中,在路基材料缺乏的状况下,利用土工格室与现场砂土可有效提高沙漠道路的承载力,并能达到经济效益与路基的设计要求。为了解土工格室于砂土路基的加筋行为,分别进行了静态承载板载重试验与动态载重试验,探讨土工格室加筋后的承载能力与动态特性。与未加筋砂土比较,土工格室发挥良好之加筋效果,其能提高砂土的承载能力;于静态承载试验中,承载能力随着土工格室高度增加而提升,并有效减少沉降量之产生。在动态试验指出,土工格室加筋于砂土受动态反复作用下,增加土工格室高度,并不相对能提升加筋的承载成效。以动态载重试验反应公路的反复载重条件,对于沙漠公路设计使用土工格室加固路基时,得以选择具有经济效益的优化方案。 相似文献
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Effective width due to deflections of composite girders with shallow height. Due to the high slenderness of composite girders with shallow height their deflection behaviour is of great importance. In many cases the cross sectional dimensions are determined by the limitation of the deflections. In contrary to high composite beams the deflection behaviour of these girders is influenced especially by the bending state and cracking behaviour of the concrete slab. Among others the deflection or the stiffness of the composite girders depend on the effective width of the slab. This article reports on investigations of the deflection behaviour and the effective width of shallow composite girders taking into account the bending state and the cracking of the concrete slab. At first it is shown that for the calculation of stresses a different value of the effective width has to be taken into account than for the calculation of deflections. On basis of extensive experimental, analytical and numerical investigations the influences on the effective width are analysed. A wide‐ranging parametric study leads to the development of an approach of the effective width for the calculation of deflections and a proposal for a quasi‐elastic calculation of the deflections of shallow composite girders. At this it turns out that the effective width due to deflections is influenced above all by the bending state of the concrete slab, its cracking behaviour, its ratio width to length, the ratio of the individual stiffness components of the composite cross section and the load level. On basis of the proposed approach for the calculation of the effective width the deflections of shallow composite girders can be determined realistically. This leads to a more economic design of composite shallow girders than until now. 相似文献
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The transient flushing of neutrally-buoyant pollutants from a naturally ventilated enclosure is investigated. A simplified transient model for buoyancy-driven natural ventilation produced by a point source of heat is presented to describe the ventilation development from the plume generation to its steady state. The instantaneous thermal stratification interface height and ventilation flow rate and the time taken for the flow to reach the steady state are then examined by the transient model. The results indicate that the decrease of the thermal stratification interface height with dimensionless time, the steady-state interface height and the dimensionless time taken for the flow to reach the steady state are only determined by the dimensionless effective area of the vents. The ventilation flow rate can be increased by decreasing the enclosure floor area or increasing the effective vent area, enclosure height or source buoyancy flux. Accordingly, for rooms with smaller floor area, larger effective vent area or larger source buoyancy flux, ventilation airflow provides more effective flushing of neutrally-buoyant pollutant. Nevertheless, increasing the enclosure height is only beneficial to flush the pollutant from the lower layer rapidly and is disadvantageous to reduce the pollutant concentration of the upper layer. 相似文献
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利用轴对称圆柱壳有矩理论进行水池设计,并进行了现场测试。设计中预应力钢筋的摩擦损失取自现场试验数据,为张拉控制应力的1 9%。工程实例表明,无粘结预应力混凝土技术应用于大直径圆柱壳可有效地控制裂缝产生,获得可观的经济和社会效益。在使用阶段,建议对0 4倍池壁高度以下截面应按偏心受拉构件计算,以上截面仍按轴心受拉构件计算。底板下的锚桩除了有效抗浮之外,还能大大降低底板的厚度。施工时应保证钢绞线与锚固壁柱上的锚垫板垂直,并选用适当的夹片式锚具,使其表面硬度与钢绞线的表面硬度差≥HRc1 0 (HRc为洛氏硬度)。 相似文献
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The steel–concrete hybrid wind turbine tower is characterized by the lower part of the traditional steel tubular tower replaced with the concrete segment. The lateral stiffness will be improved obviously, and then, the excessive vibration of the steel tower can be solved effectively. Based on the improved genetic algorithm, an optimization program is built to consider the influence of materials, labor, machinery, and transportation on the construction cost of a steel–concrete hybrid tower for a 2.0‐MW wind turbine with a hub height of 120 m, in which the initial height of the concrete segment is 32 m. During the optimization process, design requirements of relevant specifications and industry standards are used as the constraints. The optimization variables include the bottom and top diameters of the tower, the wall thickness of each segment, the height of the concrete segment, and the area of the prestressed steel strand. By comparing the results of construction cost and structural capacity before and after optimization, it can be found that the steel–concrete hybrid wind turbine tower after optimization has the better structural stiffness and lower construction cost. The proposed optimization program can meet the design requirements and significantly improve the economic performance of the tower. 相似文献
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成都某大型商业建筑,跨地铁线建设。该建筑地上部分平面约122 m×147 m,柱网为9 m×9 m,地下2层,地上7层,建筑物高40.8 m。首层以下采用12榀转换大梁支承上部结构,其跨度28 m~33.6 m不等,间距9 m。受既有地铁的影响,转换结构高度控制在6.0 m以内。工程设计中,通过整体计算分析,并作进一步的有限元分析,比较了几种不同形式大跨度转换梁的受力性能。以此为基础,进行经济性比较。通过以上各项指标的分析比较,为工程实际应用确定了最合适形式的转换大梁,创造了良好的社会效益和经济效益,同时为类似的工程设计结构选型提供了相应的依据和有益的参考。 相似文献