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BACKGROUND With the high specific surface area, rich functional groups and strong adsorption capacity, attapulgite (AT) and its modified materials have become a research hotspot in the field of heavy metal remediation of farmland soil. OBJECTIVES To investigate the stabilization mechanism and effect of different modified AT for Cd-contaminated alkaline soil. METHODS AT materials were modified by sodium hydroxide and ferric chloride. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR), and nitrogen adsorption/desorption test (BET-BJH) were used to analyze the microstructure and surface morphology of the modified AT. Combined with the characterization results, the passivation mechanism was analyzed, and the indoor simulated Cd-contaminated alkaline soil cultivation experiment and the lettuce potting experiment were carried out. Soil Cd content was determined by atomic absorption spectrophotometry. The effect differences between single application and compound application of two modified attapulgites in Cd-contaminated alkaline soil were investigated. RESULTS Alkali treatment made the Si-O groups and structural negative charges increase, and the number of micropores and specific surface area of the iron-modified attapulgite (IM) also increased. The internal pore distribution and surface morphology of attapulgite can be significantly changed in two types of modification, which can also improve their adsorption capacity. Alkali-modified attapulgite (AM) can improve soil pH and cation exchange (CEC) by stronger chemical adsorption capacity, while IM has stronger physical adsorption capacity and strong chemical adsorption capacity, which makes soil pH decrease and CEC rise. To a certain extent, the compound application of the two materials can reduce soil pH and improve CEC, which can improve their stabilization effect. After using the passivation material of AM: IM ratio of 3:1 and 2.00% of the soil mass, the available DTPA-Cd content was reduced by 33.85%, and the BCF of lettuce was reduced by 24.49%. The treatment attained the best stabilization effect. CONCLUSIONS IM has good stabilization effect on heavy metal Cd in alkaline soil. AM should be avoided for single application, and it can be recombined with other stabilization materials to achieve better reduction of soil Cd pollution while improving the quality of alkali soil.

Based on the microstructure, volume parameters and braiding angle of needled and braiding C/C composites, a unit cell model with needled areas and braiding structures is proposed, in order to study the effect of braiding structure and needled density on the overall mechanical properties of the composites. A microstructure model of needled and braiding C/C composites was established to study the effects of braiding angle and needled density on the overall elastic properties of the composites. The results indicate that there is stress concentration in the contact area between the acupuncture area and the fibers, as well as in the matrix around the fibers area. The braiding angle had a significant impact on the elastic properties of the needled and braiding C/C composites. The axial tensile test of composites was conducted according to the standard of GB/T 33501--2017, and the predicted elastic modulus of the model was in good agreement with the experimental data, with an error of 2.27% in the predicted results. The study of the microstructure of needled and braiding C/C composites can provide some basis for the design of the microstructure and exploration of mechanical properties of subsequent composites. [ABSTRACT FROM AUTHOR]

Hollow floors are widely used in structures with a large span that bear a large load. In this study, we propose a hollow floor with built-in corrugated pipes as a filling material that has the advantages of a lighter weight, higher stiffness, and lower cost than traditional floors. We first propose a novel form of stiffness by coupling the anisotropies of the material and the structure. This concept is then used to develop a theoretical formula to compute the deflection of a hollow slab set using corrugated pipes on simply supported and fixed constraints on opposite sides. We then use static loading tests to show that this hollow slab has excellent ductility and load-bearing capacity. Following this, we design a mixed finite element model of the hollow slab to predict its deflection by considering concrete, steel, and corrugated tubes. We then use six reference points on the hollow slab to verify the model in comparison with the results of the static loading test and the theoretical formula. The results show that while the maximum deformation occurred at point a1 in the middle of the slab, the maximum errors among the results of the theoretical formula, static loading tests, and the finite element model occurred at point a2. The maximum and minimum errors between the results of the theoretical prediction and the outcomes of the static loading test were 9.09% and 0%, while those between the results of the theoretical prediction and the finite element model were 8.92% and 1.19%, respectively. The proposed hollow slab, set using thin-walled corrugated tubes, can be used in a variety of engineering designs. [ABSTRACT FROM AUTHOR]

This study examines the beliefs of Chinese junior high school English teachers about foreign language teaching and influencing contextual factors in a time when curriculum innovation is confronting deep-rooted cultural traditions and complex teaching realities. Drawing upon data collected by means of questionnaires and interviews, this study reveals a multi-dimensional structure of teachers' beliefs. On the whole, teachers' beliefs are congruent with the constructivism-oriented curriculum reform, but a closer examination suggests that both traditional and constructivist beliefs exist. Constructivist beliefs favour student participation, interactive class, and learning strategy training while traditional beliefs involve focus on grammar and language form, drill and practice, rote memorization, and teacher authority. A variety of contextual factors are found to exert a strong influence on teachers' beliefs, such as Confucian culture, curriculum reform, high-stakes testing, and school environment. These factors interact to facilitate or constrain the development of teachers' beliefs. The study highlights the situated nature of teachers' beliefs with implications for curriculum reform, teacher development and many other important issues in secondary foreign language education in China and other similar contexts internationally.

To address the problem of poorly understood mechanical mechanism of stress-caused brittle failure in shale, the brittle fracture model of laminated shale with longitudinal mechanical inhomogeneity was established by applying the theory of rock fracture mechanics and combining it with generalized Hooke's law on the basis of analyzing the characteristics of laminated shale, and the main influencing factors of the fracture mode of laminated shale were analyzed. The study shows that the fracture modes of laminated shale are mainly divided into shear failure and tensile failure, hard rock formations are prone to tensile failure, while soft rock formations are prone to shear failure under external stress conditions; the larger the Young's modulus of the rock formation and the smaller the Poisson' s ratio, the more prone the formation is to tensile failure and vice versa; the larger the minimum horizontal principal stress and the smaller the horizontal principal stress difference, the more prone the formation is to shear failure; the variability of mechanical properties between shale layers is the fundamental reason for the brittle fracture of shale; the greater the variability between shale layers, the more brittle the rock is, and the more favorable it is for fracturing. This study can provide theoretical guidance for shale brittleness evaluation and hydraulic fracturing scheme development. [ABSTRACT FROM AUTHOR]

This is the second of four essays discussing Wu's "Interpretation, autonomy, and transformation: Chinese pedagogic discourse in a cross-cultural perspective" (JCS, 43(5), 569-590). The essay is interesting against the background of recent debates, both inside and outside China, about the relationship between the Chinese and Western traditions of curriculum and pedagogy. The essay helps one to understand that there is no clear divide between the so-called Chinese and Western traditions. The modern Chinese language as well as its pedagogical discourse have been hybridized with something western, with the implication that it is difficult to distinguish one from the other. However, the paper falls into a trap of cultural judgement: it (re)interprets the Confucian "authentic" texts as "desirable" and attributes many "contemporary" pedagogical practices and/or the discourse of the so-called "Confucian heritage" to the influence of the West. (Contains 2 notes.)

Classroom research has largely focused on an "instructional discourse" in local classroom contexts where teachers and students interact about subject knowledge. Few studies have been conducted, however, to examine "regulative discourse", which is the precondition for the transmission of subject knowledge. In this article, therefore, we investigate regulative discourse in Singapore primary school English Language classrooms from a perspective of Bernstein's pedagogic discourse theory. Specifically, we identify the typology of teachers' directives with morphosyntactic patterns by using corpus linguistic approach, and explore what choices teachers make of directives, for what regulatory purposes and how they position students. In this way, we illustrate how the regulative discourse is constructed and what power relations are enacted or manifested between teachers and students in the Singapore classroom context. The findings help illuminate relationships between sociocultural factors and classroom regulative practices that enable a better understanding of sociocultural specific rules of order, relation and identity in the classroom context. (Contains 2 tables and 5 notes.)

In this article, I analyse the initiation/response/follow-up (IRF) exchanges between teachers and students in teacher-fronted instruction by using transcribed classroom data. Adopting a social constructivist position, I examine ways in which teachers construct or reduce students' learning opportunities in these communications. Furthermore, I demonstrate how language is used to serve the functions of mediation and to provide learning opportunities. Although teachers talk most of the time and control most of the turns, I argue that teachers can improve their talk and control in their fronted instruction to optimise student contributions and to facilitate students' learning. (Contains 3 notes.)

This article examines the discourses of cultural values and beliefs constructed in Chinese language textbooks currently used for primary school students nationwide in China. By applying story grammar analysis in the framework of critical discourse analysis, the article critically investigates how the discourses are constructed and what ideological forces are manifested in the textbooks. More specifically, it analyses how story grammar and textual devices are manipulated in the construction of selected versions of cultural values and beliefs for the child reader. Further, it explores how the discourses position the child reader to read through the ways that the discourses are constructed, and concludes that the discourses serve the interests of the government and its cultural elites, but not the interests of the child reader. (Contains 1 table and 1 figure.)