Towards a better understanding of the political economy of regional integration in the GMS: Stakeholder coordination and consultation for subregional trade facilitation in China

The main contribution of this paper is the identification of obstacles at the different levels of coordination, and constructive recommendations for (a) improving the effectiveness of existing coordination and (b) forging linkages where necessary between the various stakeholders i.e., central and provincial governments, state-owned enterprises, the private sector – including industrial associations, and small and medium-sized enterprises (SMEs) – border communities, donors and development partners, and civil organizations are the main stakeholders.Political economy, GMS, Trade Facilitation, China

On a curvature flow model for embryonic epidermal wound healing

The paper studies a curvature flow linked to the physical phenomenon of wound closure. Under the flow we show that a closed, initially convex or close-to-convex curve shrinks to a round point in finite time. We also study the singularity, showing that the singularity profile after continuous rescaling is that of a circle. We additionally give a maximal time estimate, with an application to the classification of blowups.Comment: 43 page

Attentional Guidance from Multiple Working Memory Representations: Evidence from Eye Movements

Recent studies have shown that the representation of an item in visual working memory (VWM) can bias the deployment of attention to stimuli in the visual scene possessing the same features. When multiple item representations are simultaneously held in VWM, whether these representations, especially those held in a non-prioritized or accessory status, are able to bias attention, is still controversial. In the present study we adopted an eye tracking technique to shed light on this issue. In particular, we implemented a manipulation aimed at prioritizing one of the VWM representation to an active status, and tested whether attention could be guided by both the prioritized and the accessory representations when they reappeared as distractors in a visual search task. Notably, in Experiment 1, an analysis of first fixation proportion (FFP) revealed that both the prioritized and the accessory representations were able to capture attention suggesting a significant attentional guidance effect. However, such effect was not present in manual response times (RT). Most critically, in Experiment 2, we used a more robust experimental design controlling for different factors that might have played a role in shaping these findings. The results showed evidence for attentional guidance from the accessory representation in both manual RTs and FFPs. Interestingly, FFPs showed a stronger attentional bias for the prioritized representation than for the accessory representation across experiments. The overall findings suggest that multiple VWM representations, even the accessory representation, can simultaneously interact with visual attention

A Comparative Study Of Directional Connections In Popular U.S. And Chinese High School Mathematics Textbook Problems

Mathematical connection has received increasing attention and become one major goal in mathematics education. Two types of connections are distinguished: (a) between-concept connection, which cuts across two concepts; and (b) within-concept connection, which links two representations of one concept. For example, from the theoretical probability to experimental probability is a between-concept connection; generate a graph of a circle from its equation is a within-concept connection. Based on the directionality, unidirectional and bidirectional connections are discerned. Bidirectional connection portrays a pair of a typical and a reverse connection. The benefits of connections, especially bidirectional connections, are widely endorsed. However, researchers indicated that students and even teachers usually make unidirectional connections, and underlying reasons may be the curriculum and cognitive aspects. Previous studies have reported differences in learning opportunities for bidirectional connections in U.S. and Chinese textbook problems, but few have explored the high school level. This study addressed this issue by comparing the directionality of mathematical connections and textbook-problem features in popular U.S. (the UCSMP series) and Chinese (the PEP-A series) high school mathematics textbook problems. The results indicated that the between-concept condition and unidirectional connections dominated textbook problems. Mathematical topic, contextual feature, and visual feature were most likely to contribute to different conditions of connections. Overall, problems dealing with quadratic relations from Chinese textbooks presented a vigorous network of more unique and total between-concept connections with balanced typical and reverse directions than the U.S. counterparts. Problems from U.S. textbooks showed a denser network of (a) within-concept connections in two topics and (b) between-concept connections in probability and combinatorics than the Chinese counterparts, but still exhibited an emphasis on specific concepts, representations, and directionality. The study reached a generalized statement that the new-to-prior knowledge direction was largely overlooked in textbook problems. The results have implications for adopting graph theory and Social Network Analysis to visualize and evaluate mathematical connections and informing mathematics teachers and textbook authors to pay attention to the new-to-prior knowledge connection

RESEARCH ON COOPERATIVE LEARNING BASED ON＂ FLIPPED CLASSROOM" TEACHING MODE IN HIGHER VOCATIONAL ENGLISH TEACHING

Since its appearance, the teaching mode "flipped classroom" has quickly become a most popular teaching mode in recent years. In practice, many a scholar has tried exploring this teaching mode and has got remarkable effectiveness. According to the characteristics of "flipped classroom" teaching mode and its realization form, this paper mainly explores the feasibility of applying "flipped classroom" and analyzes the implementation strategies of cooperative learning in higher vocational English teaching

Development of Novel Nanomaterials for High-Performance and Low-Cost Fuel Cell Applications

Proton exchange membrane fuel cells (PEMFCs) are promising energy converting technologies to generate electricity by mainly using hydrogen as a fuel, producing water as the only exhaust. However, short life-time and high cost of Pt catalyst are the main obstacles for the commercialization of PEMFCs. In the conventional carbon black supported platinum nanoparticle (NP) commercial catalyst, carbon supports are prone to oxidation and corrosion over time that results in Pt NPs migration, coalescence, even detaching from the catalyst support. In addition, Ostwald ripening of the Pt NPs could also occur due to their high surface energy and zero dimensional structural features. All these contribute to the degradation of fuel cell performance. This research aims at fabricating various advanced nanomaterials, including (1) Pt-based highly efficient nanocatalysts and (2) alternative nanostructured durable catalyst supports, to address the above-mentioned challenges in PEMFCs. It is well known that the catalytic activity and durability of Pt catalysts are highly dependent on their size and shape. In contrast to commercially-used Pt spherical nanoparticles, one-dimensional (1D) structures of Pt, such as nanowires (NWs), exhibit additional advantages associated with their anisotropy and unique structure. We first reported a new approach to address both activity and durability challenges of PEM fuel cells by using 1D Pt nanowires (PtNWs) as electrocatalyst. Pt NWs were synthesized via a very simple environmentally-friendly aqueous solution route at room temperature, without the need of heating, surfactants or complicated experimental apparatus. This novel PtNW nanostructure showed much improved activity and durability than the state-of-the-art commercial Pt/C catalyst which is made of Pt nanoparticles. Further, Pt NWs were grown on Sn@CNT nanocable support to form a novel 3D fuel-cell electrode (PtNW/Sn@CNT). This approach allows us to combine the advantages of both PtNW catalyst and Sn@CNT 3D nanocable support for fuel cell applications. The PtNW/Sn@CNT 3D electrodes showed greatly enhanced electrocatalytic activities for ORR, MOR and improved CO tolerance than commercial Pt/C nanoparticle catalyst. To save more platinum, ultrathin Pt NWs with even smaller diameters of 2.5 nm (vs. 4 nm reported in our previous work) have been successfully synthesized when using N-doped CNTs as support. Direct evidence for the formation of ultrathin Pt NWs was provided by systematically investigating their growth process under TEM. Nitrogen doping in CNTs played a key role in the formation of ultrathin Pt nanowires. In terms of low durability of PEM fuel cell catalysts, the corrosion of current commonly-used carbon black support materials have been identified to be the major contributor to the catalyst failure. One of the major challenges lies in the development of inexpensive, efficient, and highly durable alternative catalyst supports that possess high corrosion resistance, high conductivity and high surface area. In this work, a series of promising alternative nanostructured catalyst supports, including 0D Nb-doped TiO2 hollow nanospheres, 1D TiSix-NCNT nanostructures, and 2D graphene nanosheets, have been synthesized by various methods and used as catalyst supports. Pt nanoparticles were then deposited on these novel supports, showing enhanced catalytic activities and durabilities. Most interestingly, a new technique, atomic layer deposition (ALD), was used to uniformly deposit Pt nanoparticles, subnanometer clusters and single atoms on graphene nanosheets. Downsizing Pt nanoparticles to clusters or even single atoms could significantly increase their catalytic activity and is therefore highly desirable to maximize the efficiency. In summary, the discoveries in this thesis contribute to applying various novel nanostructured materials to design highly active and stable electrocatalyst and durable catalyst support to develop high performance and low cost PEM fuel cells