4,073 research outputs found
Degree of hydration-based creep modeling of concrete with blended binders : from concept to real applications
The mechanical behavior of hardening concrete is to a large extent determined by the evolving microstructure as a result of the hydration process. For traditional binder systems, consisting of Portland cement or blast furnace slag cement, the degree of hydration is known to be a fundamental parameter in this respect, enabling a detailed study and accurate prediction of the early-age mechanical behavior, including basic creep. Nowadays, in view of improved sustainability of cementitious materials, binder systems tend to become more complex, consisting of a blend of different powders. As the hydration process and microstructure development are influenced by the inclusion of powders into the binder, the question is raised whether the degree of hydration concept is still applicable to concrete based on complex blended binder systems. In this paper, some experimental results are summarized and the application to real structures is illustrated. Basic creep of hardening concrete with complex blended binders can still be modeled following the degree of hydration concept
Radio Polarization of BL Lacertae objects
In this paper, using the database of the university of Michigan Radio
Astronomy Observatory (UMRAO) at three (4.8 GHz, 8 GHZ, and 14.5 GHz) radio
frequencies, we studied the polarization properties for 47 BL Lacertae
objects(38 radio selected BL Lacertae objects, 7 X-ray selected BL Lacertae,
and two inter-middle objects (Mkn 421 and Mkn 501), and found that (1) The
polarizations at higher radio frequency is higher than those at lower
frequency, (2) The variability of polarization at higher radio frequency is
higher than those at lower frequency, (3) The polarization is correlated with
the radio spectral index, and (4) The polarization is correlated with
core-dominance parameter for those objects with known core-dominance parameters
suggesting that the relativistic beaming could explain the polarization
characteristic of BL Lacs.Comment: 5 pages, 3 figures, 1 table. PASJ, in pres
Virtual Instrument for Determining Rate Constant of Second-Order Reaction by pX Based on LabVIEW 8.0
The virtual instrument system based on LabVIEW 8.0 for ion analyzer which can measure and analyze ion concentrations in solution is developed and comprises homemade conditioning circuit, data acquiring board, and computer. It can calibrate slope, temperature, and positioning automatically. When applied to determine the reaction rate constant by pX, it achieved live acquiring, real-time displaying, automatical processing of testing data, generating the report of results; and other functions. This method simplifies the experimental operation greatly, avoids complicated procedures of manual processing data and personal error, and improves veracity and repeatability of the experiment results
Separating sexual dimorphism from other morphological variation in a specimen complex of fossil marine reptiles (Reptilia, Ichthyosauriformes, Chaohusaurus).
The Early Triassic Chaohu Fauna from Anhui Province, China, contains the oldest record of Mesozoic marine reptiles, such as Cartorhynchus and Sclerocormus. Most specimens from the fauna belong to the ichthyosauriform Chaohusaurus, more specifically resembling C. chaoxianensis. However, a wide range of morphological variation exists within about 40 skeletons that have been prepared, likely reflecting mixed signals from both sexual and taxonomic differences. We test whether the sexual and taxonomic signals are separable based on quantification, aided by the knowledge of sexual dimorphism in extant marine tetrapods. There are two different suites of dimorphism that divide the specimens differently from each other yet consistently within each suite, resulting in four morphotypes in combination, likely representing two sexes of two taxa. Presumed males have larger organ of prehension sensu Darwin, specifically limbs in the present case, for a given body length. This sexing criterion is supported by the only specimen of a gravid female, which belongs to the morphotype with short limbs. Males also have larger skulls for the trunk length compared to females. This study demonstrates that sexual and taxonomic signals are separable in fossil reptiles, with a sufficient sample size and careful analyses
A multilayered approach of Si/SiO to promote carrier transport in electroluminescence of Si nanocrystals
The electroluminescence (EL) and photoluminescence of Si nanocrystals (Si-nc) from multilayered samples of Si/SiO are investigated. Si-nc are formed within Si and SiO layers after furnace annealing. It is found that the presence of Si interlayers creates extra carrier paths for EL emission. A comparative study is further performed on a multilayered Si/SiO sample and a single-layered one with Si and SiO homogeneously mixed. Both samples have the same ratio of Si to O and the same contents of Si and O. The multilayered sample is found to have higher EL intensity, less turn-on voltage, lower resistance, and higher current efficiency than the single-layered one. The results indicate that Si interlayers in Si/SiO may act as carrier channels, which promote carrier transport and enhance the EL emission of Si-nc
MiRNA-145 increases therapeutic sensibility to gemcitabine treatment of pancreatic adenocarcinoma cells.
Pancreatic adenocarcinoma is one of the most leading causes of cancer-related deaths worldwide. Although recent advances provide various treatment options, pancreatic adenocarcinoma has poor prognosis due to its late diagnosis and ineffective therapeutic multimodality. Gemcitabine is the effective first-line drug in pancreatic adenocarcinoma treatment. However, gemcitabine chemoresistance of pancreatic adenocarcinoma cells has been a major obstacle for limiting its treatment effect. Our study found that p70S6K1 plays an important role in gemcitabine chemoresistence. MiR-145 is a tumor suppressor which directly targets p70S6K1 for inhibiting its expression in pancreatic adenocarcinoma, providing new therapeutic scheme. Our findings revealed a new mechanism underlying gemcitabine chemoresistance in pancreatic adenocarcinoma cells
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