Experimental Study on the Influence of Curing Conditions on Capillary Absorption of Concrete

Both the hardening process and formation of microstructure of concrete are significantly influenced by the curing condition. The capillary absorption of concrete is closely related to the structure and distribution of the pores within the material. This paper presents an experimental study on the influence of four curing conditions, i.e., standard curing, natural curing, water curing, and sealed curing, on the capillary absorption of normal concrete. Compressive strength tests on the cylinder specimens that are core drilled from concrete slabs are carried out. The “pie” samples cut from three different locations along the height direction of cylinder specimens are then conducted to measure the ultrasonic pulse velocity (UPV) and porosity, which quantitatively characterize the internal state of concrete after 28 days initial curing. In order to realize the continuous observation of water absorption testing, an improved gravimetrical test setup for measuring the sorptivity (the rate of water absorption) of concrete is designed to investigate capillary absorption of the “pie” samples. The experimental results indicate that the curing condition has an important influence on compressive strength, ultrasonic pulse velocity, and porosity of concrete. The temperature and relative humidity are the key factors to ensure strength development during the curing procedure and to determine the internal pore structure and the compactness of concrete. For the same curing conditions, the cumulative water content, sorptivity, and porosity of concrete gradually decrease with the increase of distance from the surface, but the ultrasonic pulse velocity reverses

Semi-polar (11-22) AlGaN on overgrown GaN on micro-rod templates: Simultaneous management of crystal quality improvement and cracking issue

© 2017 Author(s).Thick and crack-free semi-polar (11-22) AlGaN layers with various high Al compositions have been achieved by means of growth on the top of nearly but not yet fully coalesced GaN overgrown on micro-rod templates. The range of the Al composition of up to 55.7% was achieved, corresponding to an emission wavelength of up to 270 nm characterised by photoluminescence at room temperature. X-ray diffraction (XRD) measurements show greatly improved crystal quality as a result of lateral overgrowth compared to the AlGaN counterparts on standard planar substrates. The full width at half maximums of the XRD rocking curves measured along the [1-100]/[11-2-3] directions (the two typical orientations for characterizing the crystal quality of (11-22) AlGaN) are 0.2923°/0.2006° for 37.8% Al and 0.3825°/0.2064° for 55.7% Al, respectively, which have never been achieved previously. Our calculation based on reciprocal space mapping measurements has demonstrated significant strain relaxation in the AlGaN as a result of utilising the non-coalesced GaN underneath, contributing to the elimination of any cracks. The results presented have demonstrated that our overgrowth technique can effectively manage strain and improve crystal quality simultaneously

Typical Correlation Analysis between Forage Type Triticale Production Performance and Different Pilot Ecological Factors

Domestic and foreign researches on triticale mainly focus on hereditary traits and excellent characteristics, but there are few reports on triticale yield and quality in the severe cold pastoral areas of Gansu and Qinghai. In this study, Gannong 2 triticale cultivars have been bred and planted in typical ecological areas according to the characteristics of different ecological regions. By studying the relationship between quality traits and various ecological factors, the effects of different ecological factors on the quality of Triticale hay have been clarified, which provides a reasonable basis for future triticale breeding and large-scale and targeted planting layout. The production performance and nutritional qualities of Triticale Trial in Maqu County, Gansu Province and Gannong No. 2 in Dulan County, Qinghai Province are obviously superior to other pilot sites. Through reasonable fertilization, the production performance and nutritional quality of triticale are the best. Triticale production performance is significantly related to climatic factors in different pilots. The most suitable planting area for Gannong 2 is Maqu County, Gansu Province

Bis(nitrato-κO)bis­[4,4,5,5-tetra­methyl-2-(5-methyl-1H-imidazol-4-yl-κN 3)-2-imidazoline-1-oxyl 3-oxide-κO]nickel(II)

In the centrosymmetric mononuclear title complex, [Ni(NO3)2(C11H17N4O2)2], the NiII atom displays a distorted octa­hedral coordination geometry and is six-coordinated by two N,O-bidentate nitronyl nitroxide radical ligands and two monodentate nitrate anions

Further Study On U(1) Gauge Invariance Restoration

To further investigate the applicability of the projection scheme for eliminating the unphysical divergence $s/m_e^2$ due to U(1) gauge invariance violation, we study the process $e^-+W^+\to e^-+\bar t+b$ which possesses advantages of simplicity and clearness. Our study indicates that the projection scheme can indeed eliminate the unphysical divergence $s/m_e^2$ caused by the U(1) gauge invariance violation and the scheme can apply to very high energy region.Comment: Latex, 13 pages, 4 EPS fiure

Neutrino oscillations in de Sitter space-time

We try to understand flavor oscillations and to develop the formulae for describing neutrino oscillations in de Sitter space-time. First, the covariant Dirac equation is investigated under the conformally flat coordinates of de Sitter geometry. Then, we obtain the exact solutions of the Dirac equation and indicate the explicit form of the phase of wave function. Next, the concise formulae for calculating the neutrino oscillation probabilities in de Sitter space-time are given. Finally, The difference between our formulae and the standard result in Minkowski space-time is pointed out.Comment: 13 pages, no figure

First complete mitochondrial genome of the tribe Coccini (Hemiptera, Coccomorpha, Coccidae) and its phylogenetic implications

Soft scale insects (Hemiptera, Coccidae) are important pests of various agricultural and horticultural crops and ornamental plants. They have negative impacts on agriculture and forestry. The tribe Coccini represents one of the most ancient evolutionary lineages of soft scale insects. However, no complete Coccini mitochondrial genome (mitogenome) is available in public databases. Here, we described the complete mitogenome of Coccus hesperidum L., 1758. The 15,566 bp mitogenome of C. hesperidum had a high A+T content (83.4%) and contained a typical set of 37 genes, with 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs) and two ribosomal RNA genes (rRNAs). Only seven tRNAs had the typical clover-leaf secondary structure and the remaining tRNAs lacked the DHU arm, TψC arm or both. Moreover, a comparative analysis of all reported scale insect mitogenomes from GenBank database was performed. The mitogenomes of scale insects showed high similarities in base composition and A+T content. Additionally, our phylogenetic analysis confirmed the monophyly of Coccomorpha and revealed that the archaeococcoids were the most basal lineage within Coccomorpha, while Ericerus pela and Didesmococcus koreanus, belonging to Coccidae, were often mixed with Aclerdidae, making Coccidae a paraphyletic group. These findings expand the mitogenome database of scale insects and provide new insights on mitogenome evolution for future studies across different insect groups