[Source Constraints on Turquoise of the Erlitou Site by Infrared Spectra].

Shiyan district in Hubei province is a famous locality of high-quality turquoise with brightcolor, finegrain in the world. Erlitou archacologicalsite, which is about 300km north to the Shiyan Turquoise mine, has been excavated a remarkable number of turquoise artifacts since 2002. Some researchers infer that there was "a road of turquoise" between the two sites in history. In order to check the inference, and identify local features of the turquoises found in Shiyan, and Eelitou site as well, spectra of three turquoise groups from Shiyan, Hubei and one group of Erlitou unearthed samples were obtained by means of IR. Their spectra have visible differences in the 1 200-950 and 700-400 cm(-1) range. Peak 1 174 cm(-1) appears only in samples from Wenfeng, and from 700 to 400 cm(-1), 5 peaks show in samples from Wenfeng while 7 peaks emerge from the other two sites. Turquoises in Erlitou site have similar spectra to those from Qingu and Yungaisi, and are more similar to Yungaisi of peak around 1 159 cm(-1). According to A = lg(1/T) , intensity of transmittance spectra were calculated and then Ratios(A783 cm(-1)/A837 cm(-1)) were yielded. The ratios of samples from Qingu, Wenfeng, Yungaisi and Erlitou site are 0.819-0.920, 0.870-1.010, 0.806-0.860 and 0.827-0.878 respectively, allowing for a suggestion that turquoise in Erlitou site was the most probable from Yungaisi. This research can be used as example for identifying origin of the unearthed turquoise relics, which is more likely a good tool for archeological research.

Insights into the Mechanism of Graphene Acting on Water and Chloride Ion Permeability of Cement-Based Materials.

Due to its excellent mechanical properties and high aspect ratio, graphene can significantly improve the water and chloride ion permeability resistance of cementitious materials. However, few studies have investigated the effect of graphene size on the water and chloride ion permeability resistance of cementitious materials. The main issues are as follows: How do different sizes of graphene affect the water and chloride ion permeability resistance of cement-based materials, and by what means do they affect these properties? To address these issues, in this paper, two different sizes of graphene were used to prepare graphene dispersion, which was then mixed with cement to make graphene-reinforced cement-based materials. The permeability and microstructure of samples were investigated. Results show that the addition of graphene effectively improved both the water and chloride ion permeability resistance of cement-based materials significantly. The SEM (scanning electron microscope) images and XRD (X-ray diffraction) analysis show that the introduction of either type of graphene could effectively regulate the crystal size and morphology of hydration products and reduce the crystal size and the number of needle-like and rod-like hydration products. The main types of hydrated products are calcium hydroxide, ettringite, etc. The template effect of large-size graphene was more obvious, and a large number of regular flower-like cluster hydration products were formed, which made the structure of cement paste more compact and thus significantly improved the resistance to the penetration of water and chloride ions into the matrix of the concrete.

Validation of a Measure of Flipped English Learning Readiness and Examination of Its Relationships With Instructional Practices, Learning Self-Efficacy, and Learning Beliefs.

This study validated the Flipped English Learning Readiness Questionnaire, and examined its relationships with teacher instructional practices, English learning self-efficacy, and language learning beliefs. A total of 442 Chinese university EFL students voluntarily participated in this research. Exploratory and confirmatory factor analysis resulted in determination of five flipped English learning readiness factors (i.e., doing previews, in-class communication self-efficacy, positive experience, intentional behaviors, and self-directed learning) with a strong psychometric basis. The composite reliability, average variance extracted, and HTMT ratio of correlations further confirmed the convergent and discriminant validity of the Flipped English Learning Readiness Questionnaire. Structural equation modeling analysis suggested that English learning self-efficacy was a significant predictor of student flipped English learning readiness among students from different year-levels. Autonomy-supportive instructional practices significantly predicted year 2 students' self-directed learning while grammar/translation-oriented learning had a significantly positive influence on year 3 students' positive flipped learning experience and intentional behaviors.

Performance-Based Evaluation of Healing Efficiency on Mechanical Properties of Self-Healing Cementitious Materials Incorporated with PMMA/Epoxy Microcapsule.

In this study, based upon the investigation of its effect on workability and the mechanical property of cementitious materials, the Box-Behnken design was adopted to establish models describing self-healing performance on mechanical properties of cementitious materials with polymethylmethacrylate (PMMA)/epoxy microcapsule in terms of healing rate of peak strength (Y1), the recovery rate of peak strength (Y2), the healing rate of Young's modulus (Y3), the recovery rate of Young's modulus (Y4), the healing rate of peak strain (Y5), and recovery rate of peak strain (Y6). This was performed under the influence of the four factors, including microcapsule size (X1), microcapsule content (X2), pre-loading (X3), and curing age (X4). The results showed the four factors significantly affect the healing rate and recovery rate of the peak strength, Young's modulus, and peak strain, except the healing rate on peak strain. Moreover, the interaction between the factors showed some influence as well. The numerically optimised values of X1, X2, X3, and X4 are 203 nm, 5.59%, 43.56%, and 21 days, respectively, and the self-healing cementitious materials with desirable mechanical characteristics (Y1 63.67%, Y2 145.22%, Y3 40.34%, Y4 132.22%, Y5 27.66%, and Y6 133.84%) with the highest desirability of 0.9050 were obtained. Moreover, the porosity of the specimen confirmed the healing performance of PMMA/epoxy microcapsules in cementitious materials.

Enhanced removal of bilirubin on molecularly imprinted titania film.

Titania film imprinted by bilirubin molecule at the surface of quartz crystal was prepared using molecular imprinting and surface sol-gel process. The molecularly imprinted titania film was characterized by FTIR spectra, and the interaction between bilirubin and imprinted film was investigated using quartz crystal microbalance (QCM) technique. Compared with pure titania film, the molecularly imprinted titania film exhibits a much higher adsorption capacity for the target molecule, and the adsorption kinetic parameter estimated from the in situ frequency measurement is about 1.6×10(8) M(-1), which is ten times higher than that obtained on pure titania film. The photocatalytic measurements indicate that the bilirubin adsorbed on molecularly imprinted titania film can be completely removed under UV illumination. Moreover, our study indicates that the molecularly imprinted titania film possesses a better stability and reusability.