不同含水率粘土在不同试验条件下的应力-应变特性

采用单轴固结试验和三轴剪切试验对饱和、湿润、风干以及烘干的藤森粘土进行了应力-应变特性研究。在试验过程中,进行了不同轴向应力水平下的恒应变率加载试验、蠕变试验以及卸载与重复加载试验。局部变形测量传感器(LDT)被用于三轴剪切试验中的轴向变形测量以提高小应变测量的精度。试验结果表明,不同含水率与饱和度的藤森粘土在单轴固结试验与三轴剪切试验条件下都表现出明显的粘塑性。它们的加载速率效应、蠕变效应都相似;而且在蠕变结束后的一小段邻域内藤森粘土的强度有明显的提高。笔者提出用参数β来描述藤森粘土的粘性。对试验结果的计算分析表明,在单轴和三轴试验条件下不同含水率与饱和度的藤森粘土的β值介于0.034到0.064之间;而且,含水率高的藤森粘土的β值大于含水率低的藤森粘土的β值,单轴试验条件下的β值大于三轴试验条件下的β值。     

Mechanochemical synthesis of indium complex oxides (InAO4; A = P, V, Nb, Ta, Sb) and their solid solutions

Indium complex oxides, InAO₄ (A = P, V, Nb, Ta, Sb), were synthesized by milling of the In₂O₃ and A ₂O₅ mixture using planetary ball mill at room temperature. Formation of these compounds was monitored by powder X-ray diffraction (XRD) and was found to be complete with 240 or 480 min. This method has been successfully extended to the synthesis of solid solutions, InP_1−x V _x O₄ and InTa_1−x Nb _x O₄, between these indium complex oxides.     

Particle growth of magnesium alkoxide as a carrier material for polypropylene polymerization catalyst

Images from scanning electron microscopy, transmission electron microscopy and X-ray diffraction profiles of typical magnesium diethoxide (MGE) particles obtained by the reaction of ethanol, metal magnesium and iodine showed the round MGE particle (tertiary particle) had a layer structure consisting of many crystalline fragments (secondary particles) comprising many minute crystals (primary particles). It was clearly shown that each precipitated secondary particle had not agglomerated, but had repeatedly grown and combined with others. From the investigation of the course of a reaction, it was suggested the MGE crystals grown on Mg metal exfoliated as “lump-like” seeds, and crystal growth on seeds proceeded such that the shapes of the final MGE particles were more spherical than those of their seeds. It was presumed from a model reaction that the enhancement of MGE solubility by I₂ addition to form the quasi-stable complex nMg(OEt)₂·MgI₂·mEtOH was the key process in the formation of plate crystals. The relationship between the size of crystalline fragments and crystallization rate (reaction rate, MGE solubility) was discussed.The catalyst, when prepared using MGE as the carrier material, exhibited exceptionally high polymerization activity than when it was prepared with MgCl₂ alcohol complex (MgCl₂·ROH). We presume that this is because particles of the MGE-based catalyst are porous, and because the formation of active species of the supported Ti and monomer diffusion progressed adequately from the surface of the particle to its internal parts.     

Residual Deformation of Geosynthetic-Reinforced Sand in Plane Strain Compression Affected by Viscous Properties of Geosynthetic Reinforcement

A series of plane strain compression (PSC) tests were performed on large sand specimens unreinforced or reinforced with prototype geosynthetic reinforcements, either of two geogrid types and one geocomposite type. Local tensile strains in the reinforcement were measured by using two types of strain gauges. Sustained loading (SL) under fixed boundary stress conditions and cyclic loading (CL) tests were performed during otherwise monotonic loading at a constant strain rate to evaluate the development of creep deformation by SL and residual deformation by CL of geosynthetic-reinforced sand and also residual strains in the reinforcement by these loading histories. It is shown that the creep deformation of geosynthetic-reinforced sand develops due to the viscous properties of both sand and geosynthetic reinforcement, while the residual deformation of geosynthetic-reinforced sand during CL (defined at the peak stress state during CL) consists of two components: i) the one by the viscous properties of sand and reinforcement; and ii) the other by rate-independent cyclic loading effects with sand. The development of residual deformation of geosynthetic-reinforced sand by SL and CL histories had no negative effects on the subsequent stress-strain behaviour and the compressive strength was maintained as the original value or even became larger by such SL and CL histories. The local tensile strains in the geosynthetic reinforcement arranged in the sand specimen subjected to SL decreased noticeably with time, due mainly to lateral compressive creep strains in sand during SL of geosynthetic-reinforced sand. This result indicates that, with geosynthetic-reinforced soil structures designed to have a sufficiently high safety factor under static loading conditions because of seismic design, it is overly conservative to assume that the tensile load in the geosynthetic reinforcement is maintained constant for long life time. Moreover, during CL of geosynthetic-reinforced sand, the residual tensile strains in the geosynthetic reinforcement did not increase like global strains in the geosynthetic-reinforced sand that increased significantly during CL. These different trends of behaviour were also due to the creep compressive strains in the lateral direction of sand that developed during CL of geosynthetic-reinforced sand.     

Degradation of bisphenol A using sonochemical reactions

The sonochemical degradation of bisphenol A in aqueous solution, a suspected endocrine disruptor, which can cause several damages for humans, animals and the environment, was investigated at different ultrasonic intensities under air atmosphere. Bisphenol A (0.50mM) was completely degraded after 10, 3 and 2h of ultrasonic irradiation at a frequency of 404kHz, and intensities of 3.5, 9.0 and 12.9kW/m(2), respectively. During ultrasonic irradiation, some aromatic intermediates such as 2-(4-hydroxyphenyl)-2-(3,4-dihydroxyphenyl)propane, commonly known as 3-hydroxybisphenol A were detected. Further cleavage of the aromatic rings resulted in other products, like formaldehyde and organic acids, also being detected. The proposed pathways of bisphenol A degradation by ultrasonic irradiation are based on the above-mentioned intermediates. The relationship between bisphenol A degradation and formation of hydrogen peroxide and nitric acid was taken into account, correlating this to the radicals that take part in the degradation process. In order to optimize the performance of the ultrasonic system, additional experiments using Fenton-like reactions were also carried out. However, the addition of iron (II) sulfate (FeSO(4)) did not increase bisphenol A degradation rates. Compared with the system without iron (II) sulfate, the total organic carbon concentration (TOC) was reduced by about 30%, at 404kHz and 9.0kW/m(2).     

Targeted proteome analysis of microalgae under high-light conditions by optimized protein extraction of photosynthetic organisms

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Microlens arrays for integral imaging system

When designing a system capable of capturing and displaying 3D moving images in real time by the integral imaging (II) method, one challenge is to eliminate pseudoscopic images. To overcome this problem, we propose a simple system with an array of three convex lenses. First, the lateral magnification of the elemental optics and the expansion of an elemental image is described by geometrical optics, confirming that the elemental optics satisfies the conditions under which pseudoscopic images can be avoided. In using the II method, adjacent elemental images must not overlap, a condition also satisfied by the proposed optical system. Next, an experiment carried out to acquire and display 3D images is described. The real-time system we have constructed comprises an elemental optics array with 54 H x 59 V elements, a CCD camera to capture a group of elemental images created by the lens array, and a liquid crystal panel to display these images. The results of the experiment confirm that the system produces orthoscopic images in real time, and thus is effective for real-time application of the II method.     

Efficient Identification of the MYC Regulator with the Use of the CRISPR Library and Context-Matched Database Screenings

MYC is a major oncogene that plays an important role in cell proliferation in human cancers. Therefore, the mechanism behind MYC regulation is a viable therapeutic target for the treatment of cancer. Comprehensive and efficient screening of MYC regulators is needed, and we had previously established a promoter screening system using fluorescent proteins and the CRISPR library. For the efficient identification of candidate genes, a database was used, for which mRNA expression was correlated with MYC using datasets featuring “Similar” and “Not exactly similar” contexts. INTS14 and ERI2 were identified using datasets featuring the “Similar” context group, and INTS14 and ERI2 were capable of enhancing MYC promoter activity. In further database analysis of human cancers, a higher expression of MYC mRNA was observed in the INTS14 mRNA high-expressing prostate and liver cancers. The knockdown of INTS14 in prostate cell lines resulted in decreased MYC mRNA and protein expression and also induced G0/1 arrest. This study confirmed that CRISPR screening combined with context-matched database screening is effective in identifying genes that regulate the MYC promoter. This method can be applied to other genes and is expected to be useful in identifying the regulators of other proto-oncogenes.     

Performance Evaluation of Magnetostrictive Small Wind Turbines Using Fe–Co Alloy–Based Clad Sheets

In this study, the Fe–Co alloy is combined with cobalt ferrite (CoFe₂O₄) and nickel (Ni) to form Fe–Co/CoFe₂O₄ and Fe–Co/Ni clad sheets and their energy-harvesting performance is evaluated. The Fe–Co/CoFe₂O₄ clad sheet exhibits an output voltage of 4.229 mV and an output power of 6.89 nW at a wind speed of 10 m s⁻¹. The energy-harvesting performance of both these clad sheets cannot be quantitatively compared owing to their different thicknesses, which result in varying volume and distance from the neutral plane. Nevertheless, the values of output voltage and power for Fe–Co/CoFe₂O₄ are higher than those for Fe–Co/Ni (2.107 mV and 0.294 nW).     

Piezoelectric Glass-Fiber-Reinforced Polymer Sensor for Structural Health Monitoring and Stiffness Sensing

Strengthening and repairing infrastructure with fiber-reinforced polymers while achieving low-cost, real-time monitoring of cracks in engineering structures is highly challenging. Herein, a piezoelectric glass-fiber-reinforced polymer (piezo-GFRP) sensor is used to monitor the mechanical behavior of cement beams with cracks under cyclic bending. The output voltage and frequency of the sensor are shown to be effective feedback signals for determining the mechanical behavior. The thin piezo-GFRP sensor shows sufficient piezoelectric sensitivity to monitor the slight variations in the mechanical behavior of the cement beams during the early stages of cracking. It is indicated in this result that such sensors have the potential for the multifunctional structural health monitoring of engineering structures.