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The codoping effect of antimony on the photocatalytic activity of visible-light-driven SrTiO 3 doped with rhodium (SrTiO 3 :Rh) was investigated. SrTiO 3 doped with rhodium and antimony (SrTiO 3 :Rh/Sb) prepared by a hydrothermal method was found to be active for photocatalytic H 2 evolution from an aqueous methanol solution and O 2 evolution from an aqueous silver nitrate solution under visible light irradiation, although SrTiO 3 doped with rhodium and no antimony was active only for the H 2 evolution. Photocatalytic activities of SrTiO 3 :Rh/Sb were strongly dependent on the ratio of codopant to dopant (Sb/Rh). Diffuse reflection spectroscopy (DRS), electron spin resonance (ESR), Raman, and action spectrum analyses revealed the contribution of rhodium and antimony to visible-light response of SrTiO 3 :Rh/Sb. Unstable and reversible Rh 3+ ions in oxidation state were the superior species for the H 2 evolution. On the other hand, Rh 3+ ions stabilized by codoping of antimony without the formation of Rh 4+ ions and oxygen defects which would work as undesirable recombination sites between photogenerated electrons and holes played an important role in the O 2 evolution. Moreover, when an IrO X cocatalyst was loaded on the surface of the SrTiO 3 :Rh/Sb photocatalyst, the photocatalytic activity of the O 2 evolution drastically increased. The apparent quantum yield for the H 2 evolution over Pt(0.3 wt%)/SrTiO 3 :Rh(1%)/Sb(1%) and the O 2 evolution over IrO X (3.0 wt%)/SrTiO 3 :Rh(1%)/Sb(1%) at 420 nm were 0.8% and 4.5%, respectively. The Z -scheme system composed of Ru(1.0 wt%)/SrTiO 3 :Rh(2%) as a H 2 -evolving photocatalyst, IrO X (3.0 wt%)/SrTiO 3 :Rh(1%)/Sb(1%) as an O 2 -evolving photocatalyst, and an Fe 3+ /Fe 2+ redox couple as an electron mediator showed photocatalytic activity for overall water splitting under visible light irradiation.

This study focused on strength properties of fiber-reinforced soil cement (hereafter FRSC), which contained PVA (polyvinyl alcohol) fiber with 14μm diameter, 8mm length, and 0.6% volume fraction. We conducted two series of experiments, mixing tests with different soil cement matrix mix proportions, and execution tests of FRSC column. As the result of material strength tests for laboratory mixed samples, improvement in tensile strength was the most significant: about four times higher than that of plain soil cement (hereafter SC). And modulus of rupture of FRSC also increased 2-3 times above those of SC. Execution test was conducted at loamy ground, using the machine for Soil Mixing Wall Method, and material strength tests of sampling specimen were carried out. Direction dependence of modulus of rupture was found, but executed FRSC column had approximately high-performance ductility close to that of laboratory mixed samples.

The purpose of this paper is to evaluate the relation between initial shear modulus and shear strength of cohesive soils. The initial shear moduli were obtained from the results of the well -shooting tests by means of shear waves, while the shear strength could be obtained from the results of laboratory tests conducted on undisturbed soil samples collected at the same site as the well-shooting tests. Taking into consideration the fact that there have been a number of instances where the well-shooting test and the standard penetration test were conducted on the same sites, the authors conducted their research to seek some relationships between the initial shear modulus and the N-value of the standard penetration test, between the shear strength and the N-value, and between the initial shear modulus and the shear strength. The research works have finally led the authors to finding out several relations among initial shear modulus, shear strength and N-value.