Kinetic Pathways of Order-Disorder and Order-Order Transitions in Weakly Segregated Microstructured Systems

The kinetics of hexagonal to disordered and hexagonal to body-centered-cubic phase transitions in weakly segregated, microstructured systems (e.g., diblock copolymers) is studied using a time-dependent Ginzburg-Landau (TDGL) approach. Both computer simulation of the TDGL equation and analysis of a simplified two-mode model reveal nontrivial pathways during the transition

Transient instability upon temperature quench in weakly ordered block copolymers

We report a novel transient instability upon temperature quench in weakly ordered block copolymer microphases possessing a soft direction or directions, such as the lamellar and hexagonal cylinder (HEX) phases. We show that reequilibration of the order parameter is accompanied by transient long wavelength undulation of the layers or cylinders—with an initial wavelength that depends on the depth of the temperature quench—that eventually disappears as the structure reaches its equilibrium at the new temperature. Such undulation leads to a transient transverse broadening of the scattering peaks near the Bragg positions. We argue that this instability might be responsible for the experimentally observed unusual ordering dynamics of the HEX phase of a diblock copolymer after quenching from the disordered state

Nonlinearity, Feedback and Uniform Consistency in Causal Structural Learning

The goal of Causal Discovery is to find automated search methods for learning causal structures from observational data. In some cases all variables of the interested causal mechanism are measured, and the task is to predict the effects one measured variable has on another. In contrast, sometimes the variables of primary interest are not directly observable but instead inferred from their manifestations in the data. These are referred to as latent variables. One commonly known example is the psychological construct of intelligence, which cannot directly measured so researchers try to assess through various indicators such as IQ tests. In this case, casual discovery algorithms can uncover underlying patterns and structures to reveal the causal connections between the latent variables and between the latent and observed variables. This thesis focuses on two questions in causal discovery: providing an alternative definition of k-Triangle Faithfulness that (i) is weaker than strong faithfulness when applied to the Gaussian family of distributions, (ii) can be applied to non-Gaussian families of distributions, and (iii) under the assumption that the modified version of Strong Faithfulness holds, can be used to show the uniform consistency of a modified causal discovery algorithm; relaxing the sufficiency assumption to learn causal structures with latent variables. Given the importance of inferring cause-and-effect relationships for understanding and forecasting complex systems, the work in this thesis of relaxing various simplification assumptions is expected to extend the causal discovery method to be applicable in a wider range with diversified causal mechanism and statistical phenomena

Promoting Student’s Online Engagement with Communication Tools

This case study investigated students’ engagement and learning experiences in online courses through Blackboard CE6 (Course Management System). The meaning that students gave to their learning experiences and the problems they encountered were also investigated in order to understand how students learn in a technology-enriched learning environment. Data were col­lected through open-ended survey questions, participant observations, and document analyses from three online instructional technology graduate courses where students used threaded dis­cussion, live classroom, chat room, and email for online communication and interaction. Find­ings indicated that students’ engagement was promoted by using various communication tools although student preferred discussion board and email to other tools. This study also illustrated the strengths and weaknesses of each tool and discussed the issues of using these tools as well as student’ perspectives on using these tools to promote their interaction and collaboration

Adopting Cell Phones in EFL Teaching and Learning

Though Mobile Learning (ML) has a brief history of no more than four decades, the medium is developing rapidly with the upgrading of different mobile devices. Among all the devices, cell phones have great potential in language teaching and learning. This article explores the different devices especially cell phone use in ML. The paper also reviews teaching and learning of English as a Foreign Language (EFL) in China and discusses potential applications of cell phones in Chinese EFL teaching and learning

Criteria for Selecting Trisyllabic Words as Headwords in the Chinese-French Dictionary

In the 2015 concluding report An Approach to Revising Chinese-French Dictionary—Resequencing Entry Words, sponsored by Lexicographical Studies Center at Guangdong University of Foreign Studies, we put forward three criteria for adjusting trisyllabic words based on their disyllabic. The three criteria suggest to maintain, deprive or restore the use of trisyllabic words as headwords for separate entries. Considering the vastness of this word category, as well as it’s complicated intrinsic semantic relations and diversified grammatical features, this paper takes thirty trisyllabic words that fall in Yang Shujun’s “Nine Structure Categories” as an example to check whether the above three criteria can be applied in reality and promoted widely through a method of word prosody trichotomy (trisyllabic words are classified into three general patterns, namely [1+1+1], [2+1], and [1+2])