Relation of the infrasound characteristics and the continuous steel bridge vibration modes generated by the vibration of moving heavy trucks

Railway Engineering Science - As heavy trucks pass over highway bridges, bridge vibration occurs and generates infrasound. General trucks in Japan with rear leaf suspension have whole body...     

Corrosion damage assessment method for steel guardrail post roots

Steel guardrail posts are typically used on the highway system of Japan, but these can experience the corrosion damage at their root near the road surface. This damage may be particularly severe in the seaside areas or regions that experience cold weather and employ salt as a deicing agent. Therefore, this study aimed to develop a non-destructive way of estimating the extent of corrosion in the guardrail post roots. Particularly, 11 test specimens were parametrically designed to investigate the efficiency of using the impact vibration mode to assess the corrosion damage. The corrosion angle, range and thickness at the post root were the main parameters. Meanwhile, a parametric FEM analysis was executed as well to analyze the vibration behavior, the stiffness and the load-carrying capacity. In general, the study reveals that the high-order vibration modes are sensitive to the corrosion damage at the guardrail post roots, and based on this, an impact vibration method for assessing the corrosion damage was proposed.     

成型性和焊接性优良的超高抗拉强度钢的开发

概述了JFE开发并商业化生产成形性和焊接性均优良的780—1470MPa超高强度系列冷轧钢板。该系列钢板可实现汽车减重,提高碰撞安全性能。该系列钢板是JFE采用自主开发的WQ—CAL（水淬-连续退火生产线）工艺生产的,采用该工艺可以大幅降低钢中合金元素的添加量。其中新开发的1180MPa级抗拉强度钢板的伸长率得到大幅提高,是传统相同级别钢板的1．5倍,与980MPa级钢相同,且其拉伸凸缘性也与980MPa级钢相当。另外,1180MPa级钢的加工淬透性和烘烤硬化性也十分优良,完全可以替代热冲压部件。新开发系列钢可用于白车身结构件,如中梁（加强件）、保险杠、座椅结构架、座椅横挡及座椅部件（如机械锁扣）等多种用途。     

Ultra intense glass laser system and laser–plasma interactions

The 30 TW GEKKO MII short pulse laser (25 J in 0.71 ps at 1 μm) is completed and is used for fast ignitor and particle accelerator research. The photon pressure of the laser at 10¹⁷-10¹⁸ W/cm² pushed the critical and quarter critical density plasmas forward, resulting in the strong red shifts of the second (2ω₀) and three-halves (3ω₀/2) harmonic emissions backscattered from CH or CD planes. A few hundred keV proton and deuteron emissions are also observed from CD planes.     

锑(Ⅲ)—5-Br-PADAP配合物电化学行为的研究和分析应用

在HAc—NaAc(pH6.22)缓冲溶液中,锑(Ⅲ)与5-Br-PADAP在-0.64V(υs.SCE)处有一灵敏、对称的二次导数示波极谱电流,锑(Ⅲ)浓度在0.004～2.5μg/ml与峰高成正比,检出限0.0015μg/ml.配合物至少稳定15h.方法可用于高温合金钢中微量锑的测定.文中研究了其配合比、电流特性及电极反应的可逆性,计算了其条件常数(β)、电子转移数(n)及其系数(α),还讨论了表面活性剂CTMAB对峰电流的增敏机理.     

A Compartmental Silica Nanoreactor for Multienzyme-Regulated Superactive Catalytic Therapy

Many tumor therapies take advantage of upsetting the redox balance in tumor cells, but to do so requires excessive biochemical or physical attacks. The high-throughput simulation using multi-pathway techniques described herein can yield an increased efficacy in bio-oxidation. In this study, compartmental hierarchical nanoreactors are developed as an efficient multi-pathway singlet oxygen (¹O₂) generation system for superactive biocatalytic tumor therapy. The penetrated super cavity and connected dual-mesopore channels of the compartmental multienzyme nanoreactors are designed using the proposed heterogeneous template assembly for multi-enzyme complex (superoxide dismutase (SOD)-lactoperoxidase (LPO)) and photosensitizer molecule (indocyanine green (ICG)) encapsulation. Benefiting by the enhanced direct substrate diffusion between the interacting SOD–LPO complex and decrease in external diffusion, the parallel catalysis combined by the superactive cascade biocatalysis and enzyme-promoted photosensitization effect is verified by this compartmental silica nanoreactor system. The parallel pathways not only make full use of the products of SOD (H₂O₂ and O₂), but also exhibit outstanding capability for ¹O₂ production, at ≈2.15 and 1.70 times augmented ¹O₂, respectively. Both in vitro and in vivo studies demonstrate the synergetic ¹O₂-mediated inhibition of tumor proliferation, lending this strategy great potential for the treatment of hypoxic tumors.     

The impact vibration-based fatigue damage assessment of steel and steel fiber reinforced concrete composite girder

The steel-concrete composite girder has been usually applied in the civil structures. The current fatigue damage assessment on the composite girder, especially the negative bending region, mainly bases on the crack observation and deflection measurement. It is not stable sometimes, thus the impact vibration-based fatigue damage assessment was considered instead. A 3.3m steel-steel fiber reinforced concrete (SFRC) composite girder was designed and tested. The fatigue load, the impact load, and the static load were applied in the test. It showed that the local fatigue damage reflected by the tensile SFRC cracks may not be easily evaluated through observing the global mechanical change. However, the vibration modal parameters such as the vibration frequency, vibration mode, damping ratio might be useful for this. In particular, the vibration mode variation, which can be expressed by the Modal Assurance Criterion (MAC) value, may reflect the local fatigue damage on the composite girder.     

Structural Behavior of Reinforced Concrete Slab Rigid-frame Bridge with H-Shaped Steel Girders

This study aims towards the improvement of a reinforced concrete rigid-frame bridge in an effort to reduce the construction and maintenance costs, and achieve an improved seismic performance. Correspondingly, a new structural rigid connection is proposed for H-shaped steel girders and reinforcing bars at the corner of the rigid-frame structure. Both experiments and numerical analyses were performed. Prototype models were constructed and subjected to static loading tests to reveal their load-carrying capacity and failure mode. Numerical models were then developed using finite elements to evaluate the experimental results. Analyses elicited good agreement between simulation and experimental data and validated the numerical models. Moreover, the validity of the proposed rigid connection was confirmed, and the failure behavior was clarified. Finally, a full-size model of the reinforced concrete rigid-frame bridge with H-shaped steel girders was constructed and subjected to destructive loading tests to evaluate structural integrity of the proposed rigid connection.