电子束辐照防治不同品系米象成虫及对大米蒸煮品质的影响

针对储粮害虫的磷化氢抗性问题,采用电子加速器对磷化氢抗性品系和敏感品系米象成虫及大米进行辐照处理,研究了0~1000Gy的电子束辐照对两品系米象的致死效应,分析了二者对辐照的敏感性,并研究了0~5000Gy剂量辐照下大米的蒸煮品质。结果表明,电子束处理对两品系米象的致死规律大致相同,二者对电子束的敏感性存在差异,但差异不显著。电子束辐照对大米的蒸煮品质影响显著,随辐照剂量的升高,大米的胶稠度升高,吸水率、膨胀率和感官评分降低,5000Gy时蒸煮米饭出现明显的褐变。因此,100Gy~3000Gy的剂量可以作为电子束辐照防治不同品系米象的适宜剂量。     

Calculation Method of Shear Behavior of Hybrid Fiber Reinforced High Performance Concrete Deep Beams

The static tests on hybrid fiber (steel fiber and polypropylene fiber) reinforced high performance concrete deep beams according to the orthogonal experimental design were conducted. The shear capacity and calculation method of deep beams were discussed as well. The contributory factors such as the characteristic parameters of steel fiber (types, volume fraction, aspect ratio), the volume fraction of polypropylene fiber, the ratio of web horizontal reinforcement and the ratio of web vertical reinforcement were analyzed. Results show that the shear failure mode of deep beams is changed with adding a reasonable volume of hybrid fibers, and hybrid fiber can greatly increase the diagonal cracking strength and shear strength of HPC deep beams. The diagonal cracking strength is increased by 45.2% averagely while the shear strength is increased by 25.6% averagely. A satisfied result is obtained when the plasticity theory is used to analyze shear behavior of hybrid fiber reinforced HPC deep beams. The contribution of web horizontal reinforcement and web vertical reinforcement to shear strength of deep beams is not obvious but the former plays a major role. After analyzing the strengthening mechanism of hybrid fiber, a formula to calculate the shear capacity of hybrid fiber reinforced HPC deep beams is presented based on spatial strut-and-tie mode and splitting failure.     

Reinforced Concrete Beam's Stiffness Degeneration Regulation and its Calculation Formula Under the Action of Fatigue Load

Fatigue failure is a fatal damage for the reinforced concrete structure bearing fatigue load repeatedly. That how to estimate or describe the degree of fatigue damage is a challenge in areas of structure damage and lifespan estimation. Structure's stiffness degenerates irreversibly along with the damage progress. There is a certain inherent relevance between stiffness degeneration and fatigue damage. A series of fatigue tests were carried out to study stiffness degeneration regulation due to its simplicity and feasibility. According to the test results, reinforced concrete beam's stiffness degeneration presents a three-stage rules obviously, and the stiffness degeneration curves accord with "S" style. Based on the stiffness degeneration regulation, the reinforced concrete beams' stiffness degeneration calculation formula is obtained by fitting experimental data. The formula has a perfect goodness of contact area with 10 test beams' experimental results, and it can describes reinforced concrete beams' stiffness degeneration perfectly. The formula can be used to forecast the deformation developing. Meanwhile, the residual life of the structure can be used to decision structure's fatigue fracture and the degree of performance degradation.     

Fire Resistance Analysis of High Strength Q460 Steel Beams-Part II：Theory Validation

In the previous companion paper, the fire resistance of high strength steel beams made from Q460 was theoretically studied. The methods to obtain temperature distribution, critical moment, critical temperature and stability coefficient were presented. The temperature distribution and load bearing capacity was analyzed by finite element method, and the validation was evaluated by comparison of results between theoretical computation and finite element analysis as well as experimental results. The comparison was made between Q460 steel beam and mild Q235 steel beam and the difference on fire resistance was obtained. A simplified approach for fire resistance of high strength Q460 steel beams was proposed and an example was given to show the application and reference of the approach.     

N+ 离子束注入对毛叶山桐子种子萌发、幼苗生长 和碳氮含量的影响

为了解N⁺离子束处理对毛叶山桐子种子萌发和表型的影响，采用4种不同能量N⁺离子束（0、20、25和30 keV，同一剂量4×10¹⁵ N⁺·cm^-2）注入毛叶山桐子（Idesia polycarpa Maxim. var. vestita Diels）种子，比较分析其种子的发芽率、容器苗株高、冠幅、叶片数、地径和叶片全C、N含量，以筛选出最适宜种子萌发和营养生长的N⁺离子束注入能量。结果表明，与CK比较，30 keV处理可显著增加种子发芽率、幼苗株高、冠幅、叶片数、叶片全N含量，显著减少了C/N；25 keV处理对种子发芽率、幼苗株高、冠幅、叶片数和地径无显著影响，但显著增加了叶片全C、N含量；20 keV处理对种子发芽率、幼苗冠幅、叶片数和地径增加无显著影响，对株高增加有一定促进作用，并显著增加了叶片全C、N含量。因此，在进行毛叶山桐子容器育苗时，30 keV是最有利其种子萌发和幼苗营养生长的N⁺离子束注入能量。     

Beam pumping process modeling and parameters optimization based on generalized regression neural networks for energy conservation

This paper presents a data-mining-based beam pumping unit process modeling and parameters optimization method to solve the problem of inefficiency and energy-intensive of beam pumping unit. The ideality of process parameters is one of the main factors influencing system efficiency and energy consumption, while the effectiveness of mode plays a key role in process parameters choosing. Beam pumping unit system is a complicated nonlinear system, and is hardly to be precisely described by precise mathematical models. Generalized regression neural network (GRNN), which is powerful in nonlinear mapping and generalization, is suitable for nonlinear systems. Therefore, GRNN is proposed to model the beam pumping unit in this paper, and the experimental results show that the fitness is good. Then the trained model is applied to optimize the decision parameters by vector evaluated particle swarm optimization based on Pareto (VEPSO-BP), and at last the resulting parameters are applied to the production. Experimental results show that after using the optimal parameters, the efficiencies and energy consumptions increase more than 6.6% and decrease more than 4.1% respectively, which illustrates the feasibility and effectiveness of the proposed method.     

横向正应变对梁接触问题的影响

应用深梁理论，分析了受均布荷载悬臂梁与刚性地基接触的全过程。消队 了接触区间端占的集中反力，其接触区间明显大于只考虑剪切变形的梁理论的结果，揭示了横正应对梁的接触问题有着不可忽略的影响。