Fruit softening correlates with enzymatic activities and compositional changes in fruit cell wall during growing in Lycium barbarum L.

The present study aims to examine fruit cell wall-associated fruit softening in Lycium barbarum L. by the microstructure of the fruit cells and the changes in the contents of cell wall components, molecular weights of cell wall polysaccharides and the activities of related cell wall degrading enzymes at different development stages of L. barbarum L. fruit. Fruit firmness significantly declined during ripening, with the greatest reduction between the 28 and 35 days stages. The decrease in firmness correlated with an extensively deformed microstructure in the parenchyma tissues and positively correlated with reductions in the contents of fruit cell wall materials and molecular weight in cell wall polysaccharide. Cellulase, α-galactosidase, polygalactosidase and pectin methylesterase showed higher activities during 28 days; whereas, the activities of β-galactosidase were higher during 35 days. These results indicate that cell wall-related processes are a key feature of early softening in L. barbarum L.     

Influence of bio-clogging on permeability characteristics of soil

It is necessary to enhance the barrier performance of cutoff walls in order to improve the contamination control level, especially for reconstruction or expansion of existing landfill sites. This paper presents a comprehensive laboratory investigation on the synergistic effects of microorganisms and fibers on the hydraulic conductivity of silty sand to evaluate the applicability to the field condition as an alterative barrier material. Inside the soil, the added carbon fibers not only provided good biocompatibility, but also formed spatial three-dimensional network between soil particles to improve the bacterial adhesion that eventually caused 2–3 orders of magnitude decrease in soil permeability. The resistance of the biofilm to extreme conditions was tested by permeation with solutions of different salinity and pH values, and by subjecting specimens to various hydraulic gradients and soil conditions. Despite the microbial growth inhibition occurred at these conditions, however, biofilm can largely remain intact and continue to reduce k, which due to the gradual adaptation of microorganisms to the extreme environment and the gradual recovery of their activity. Results of these tests demonstrate that biofilm treatment may be a feasible technology for creating waste containment barriers in soil.     

Experimental investigation of the effects of contraction on tsunami-induced forces and pressures on a box section bridge

Many bridges that lie within possible tsunami inundation zones are critical links in transport networks. Some efforts have been made to determine the effects of tsunamis on bridges, but only a limited range of published design guidelines are available. Therefore, it is necessary to further investigate the effects of tsunamis on bridges. In the current study, physical modeling experiments were carried out to measure bore impact forces and pressures for various tsunami bore strengths on a bridge deck with different abutment types (wing wall and spill-through) and different opening and submergence ratios. The experiments were conducted in a wave flume with dimensions of 14 × 1.2 × 0.8 m (length × width × height), equipped with an automatic gate designed to generate a tsunami bore. The horizontal and vertical forces showed an increasing trend with increasing submergence ratio for both types of abutment. However, the horizontal force showed a decreasing trend as the opening ratio decreased, while the vertical force initially increased as the opening ratio decreased, until it reached a peak value, and then it started to decrease. The overall shapes of the results for both types of abutment are similar, with higher values for spill-through abutments due to their lower energy dissipation rates. Based on the experimental data, empirical equations are proposed for estimation of tsunami loads as a function of opening and submergence ratios.     

有机保温板薄抹灰外墙外保温系统修复改造研究

结合有机保温板薄抹灰外墙外保温系统的特点,通过具体修复工程案例介绍,研究了注浆法和表层加固法在既有建筑修复改造工程中的应用。     

三维石墨烯-碳纳米管/水泥净浆的压敏性能

为了探索三维石墨烯-碳纳米管(G-CNTs)/水泥净浆的压敏性能,采用四电极法研究了荷载作用下GCNTs/水泥净浆的电阻率变化,并分析不同G-CNTs掺量、加载幅度、加载速度以及恒定荷载对电阻率变化的影响。研究表明:随着G-CNTs掺量的增加,电阻率呈先减小后稳定的变化趋势,在G-CNTs掺量由0.2wt%增加至1.6wt%时,电阻率下降51.8%;电阻率与温度呈负相关;G-CNTs掺量高于0.8wt%时可以显著提高水泥净浆的压敏性能,且电阻率变化率与应力应变有明显的对应关系,1.2wt%G-CNTs掺量下试件的应力灵敏系数和应变灵敏系数分别为2.3%/MPa和291;G-CNTs/水泥净浆电阻率变化率幅值随着加载幅度增大而相应增加,其电阻率变化率曲线在不同加载速度以及恒定荷载作用下均与应力-应变曲线一一对应,具有良好的压敏特性。     

15层全剪力墙结构居民楼定向爆破拆除

介绍了复杂环境下15层居民楼的定向爆破拆除案例,根据工程特点及周围环境制定了向西南方向倒塌的爆破方案。对1层⁵层非承重墙、楼梯进行局部预拆除;采用重心移出的方法计算爆破高度;计算了楼房的质量,用来确定预留墙体的面积;采用多重闭合电-非电复式起爆网路。通过合理的方案设计和参数选取,取得了良好的爆破效果,塌落振动未对周围建筑产生影响,可为类似工程提供参考。     

综放工作面留设合理小煤柱尺寸研究

孔庄煤矿综放工作面先前留设17～20m大煤柱护巷,巷道处于高应力区,维护十分困难。为保证巷道安全和提高煤炭采出率,现采用理论计算、现场观测和数值模拟方法综合确定小煤柱合理尺寸,选择合理的掘巷时间,为类似条件下煤柱留设提供理论依据。     

用潜孔钻处理岩墙根底的实践

本文介绍了永平铜矿露采深孔台阶爆破后出现岩墙、根底的产生原因、处理方法和在实际处理过程中所要注意的问题。     

SP预应力空心板在钢结构厂房围护结构中的应用研究

对SP预应力空心板用作围护结构墙板进行了研究,参照国家建筑标准图集《SP预应力空心板》(99ZG408)的板型并结合生产工艺流程,对SP板的结构性能及配筋形式进行了分析计算和调整,使其在不同于楼板的受力情况下能满足使用要求。这样,不仅拓宽了SP板对于大型钢结构厂房的应用范围,同时也为钢结构厂房围护墙体的设计提供了新的思路。     

减力板式挡土墙的受力分析及应用

减力板式挡土墙结构设计的一次飞跃，论文阐述了其受力特点，结合实际工程论证了其优越性和可推广价值。