降低调压器出口压力减小输差的可行性分析

对通过降低调压器出口压力来减小输差的理论基础进行探讨.结合工程实例,对该方法进行可行性分析.     

Cyclic testing of steel column-tree moment connections with weakened beam splices

Traditionally, the beam splice assemblies of column-tree connections are designed according to the full-strength design principle. Actually, the beam splice is set up at a certain distance from the column face, thus the plastic moment capacity of the beam splice does not need to be greater than the plastic moment capacity of the beam. This paper experimentally presents the effects of the weakened beam splice on the seismic performance of column-tree steel moment connections. Cyclic tests of two column-tree connection specimens with weakened beam splices and one specimen following the full-strength design principle were conducted to verify their inelastic behavior and failure modes. The test results showed that the moment resisting capacity of the column-tree connection specimens with weakened beam splices did not obviously decrease. Also, their energy dissipation capacity was better than that of the specimen following the full-strength design principle.     

太阳能热水系统设计的计算分析

太阳能热水系统是近年来发展最快、最有活力的可再生能源利用技术。本文结合建筑工程热水系统的相关节能政策,结合工程实例对集中浴室的太阳能热水系统计算进行详细的剖析,希望能对同行在设计过程中提供帮助。     

高速公路路基沉降的蠕变模型预测

采用粘弹性蠕变模型，合理计算了实际高速公路工程路基的沉降，预报了该公路的工后沉降量，根据预报结果，可以为选择合适的路面铺筑时间提供科学依据。     

中庭火灾烟气测试方法的研究

主要论述了国内外中庭建筑内火灾实验时根据火灾和烟气特性对一些相关参数进行测试的手段和方法 ,认为应根据实验条件的不同 ,灵活选择并建立相应的测试系统平台。     

为推行清单计价模式建立完善的地方造价信息网

文章探讨了工程量清单计价模式下信息技术对工程量清单计价体系的影响,提出了建立完善的地方造价信息网的途径。     

房屋节能检测中的抽样方案

分析了双百分比抽样的OC曲线,认为双百分比抽样缺乏理论依据,房屋保温隔热性能检验应采用建立在数理统计基础上的检验标准.论述了制定房屋保温隔热性能检验抽样方案时要考虑的因素,建议可采用国家抽样检验标准GB/T13262-91、GB/T13264-91作为检验的依据,并指出了在使用时要注意的问题.     

Sharpening polycrystalline phase boundary for potassium sodium niobate ceramics with MnF2 modification

The influence of anion on structure and performance is unclear in potassium sodium niobate ((K,Na)NbO₃; KNN)-based ceramics, while cation doping has been widely researched. Here, the phase structure and electrical properties are explored in MnF₂-doped KNN ceramics. Significantly, sharp rhombohedral–orthorhombic (R–O) and orthorhombic–tetragonal (O–T) phase boundary as well as reduced diffusion degree is exhibited in the ceramics along with little changed phase transition temperatures due to the optimized F⁻ content at O site, which is different from that of cation replacement for A and B sites. Notably, the domain wall motion is facilitated due to the increased A vacancy and decreased O vacancy along with strengthened polarity, originating from the higher valence state and electronegativity of F⁻ with respect to O²⁻. And then, enhanced ferroelectricity is realized via MnF₂ modification, the piezoelectricity is elevated in turn. This work presents a new idea of anion doping for controlling structure and properties in perovskite materials.     

A New Clearance Design Method for Reciprocating Fuel Pumps of Medium-Speed Diesel Engines

A new clearance design method is proposed for a reciprocating fuel pump. Structural and hydrodynamic lubrication analyses were conducted to design the clearance of the pump, and the former was used to evaluate the clearance reduction due to the deformation that results from applying maximum supply pressure. The reduction in the maximum clearance was used as the limit of the design, and the two-dimensional Reynolds equation is used to evaluate the lubrication characteristics of the pump with variations in the viscosity and clearance. The optimal clearance in the pump must be separately designed in both the stem and the head because the lubrication characteristics and the deformation patterns of the two parts are different. The validity of the numerical model was then verified by determining that the position of the wear was also similar to that of the minimum film thickness. Moreover, a rig test system was also used to verify the clearance of the proposed design method.     

移动学习App在客观题备考中的应用研究

移动学习app是一种新兴的教育技术,客观题是标准化考试的一种主要形式。本文以参加高级职业资格证考试的本校学生为实验对象,通过云班课app设计测验、头脑风暴、投票问卷等40余项多元化备考活动,研究了移动学习app在客观题备考中的应用方法及应用效果。实践数据分析表明,移动学习app满足了学生不受时空限制的个性化学习的需求,提高学生学习客观题的积极性和学习效率,并大幅提高了学习成绩和考试合格率。