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Aluminum nitride (AlN) ceramics are suitable substrate and package materials for high-power integrated circuits.

Dense AlN ceramics with Y₂O₃ and LaF₃ as sintering additives are prepared. The effects of these additives on the density, phase composition, microstructure and thermal conductivity of AlN ceramics are investigated.

Results show that 2 Wt.% Y₂O₃-doped additive is insufficient for the samples to achieve the full densification sintered at 1,700°C. When LaF₃ is added with Y₂O₃, the samples are perfectly densified at the same sintering condition. The relative density and thermal conductivity of the samples are 97.8-99.07 per cent and 169.104-200.010 W·m-1·K-1, respectively. The density of the samples and their microstructure, especially the content and distribution of secondary phases, is necessary to control the thermal conductivity of AlN ceramics.

Y₂O₃ and LaF₃ additives can effectively promote densification and enhance the thermal conductivity of AlN ceramics in a low sintering temperature, and the AlN ceramics added with Y₂O₃-LaF₃ might have potential applications in package materials for high-power integrated circuits.

This paper aims to help scholars to know the frontiers in the strategic management field. On studying, it was noted that business strategic management originated from America in the 1960s and has experienced more than half a century. However, strategic management development lacks systematical summary in the twenty-first century. The scientometric method was appliedto find out the frontiers and progress of the research of strategic management in the twenty-first century, based on the literature from 2001 to 2012 in the Strategic Management Journal.

In the paper, the authors mainly used the scientometric method and applied keywords, co-occurrence method combined with multistatistical methods and mutation words analysis, author co-citation, literature co-citation and keywords co-occurrence (national).

The findings show that the strategic management research focuses on the following theories and academic thoughts: knowledge-based view, network organization research and dynamic capability are the mainstream; besides, strategy risk, the stakeholders analysis of strategy management, corporate reputation and strategic concept also attract the attention of researchers; Barney, Teece and Porter have made significant contributions to strategy management research since the twenty-first century.

The findings in the paper will help scholars in the field of strategic management to know the main frontiers of the theory, as well as the main contributors.

The purpose of this work is to controllably synthesize a carbon aerogel with programmable functionally graded performance via a simple and effective strategy.

This work uses polyvinyl alcohol (PVA) via the controllable sol-gel, lyophilization, and carbonization approach to achieve a programmable carbon aerogel. This design has the advantages of low raw material and preparation cost, simple and controllable synthetic process and low carbonization temperature.

The thermal stability and microstructure of PVA aerogel can be controlled by the crosslinking agent content within a certain range. The crosslinking agent content and the carbonization temperature are the key factors for functionally graded programming of carbon aerogels, including microstructure, oxygen-containing functional groups and adsorption performance. The adsorption ratio and adsorption rate of uranium can be controlled by adjusting initial concentration and pH value of the uranium solution. The 2.5%25 carbon aerogel with carbonization temperature of 350 °C has excellent adsorption performance when the initial concentration of uranium solution is 32 ppm at pH 7.5.

As a new type of lightweight nano-porous amorphous carbon material, this carbon aerogel has many excellent properties.

This work presents a simple, low cost and controllable strategy for functionally graded programming of novel carbon aerogel. This carbon aerogel has great potential for application in various fields such as uranium recovery, wastewater treatment, sound absorption and shock absorption.

The construction industry is an industry with a high incidence of safety accidents, and the interactions of unsafe behaviors of construction workers are the main cause of accidents. The neglect of the interactions may lead to serious underestimation of safety risks. This research aims to analyze the cascading vulnerability of unsafe behaviors of construction workers from the perspective of network modeling.

An unsafe behavior network of construction workers and a cascading vulnerability analysis model were established based on 296 actual accident cases. The cascading vulnerability of each unsafe behavior was analyzed based on the degree attack strategy.

Complex network with 85 unsafe behavior nodes is established based on the collected accidents in total. The results showed that storing in improper location, does not wear a safety helmet, working with illness and working after drinking are unsafe behaviors with high cascading vulnerability. Coupling analysis revealed that differentiated management strategies of unsafe behaviors should be applied. Besides, more focus should be put on high cascading vulnerability behaviors.

This research proposed a method to construct the cascading failure model of unsafe behavior for individual construction workers. The key parameters of the cascading failure model of unsafe behaviors of construction workers were determined, which could provide a reference for the research of cascading failure of unsafe behaviors. Additionally, a dynamic vulnerability research framework based on complex network theory was proposed to analyze the cascading vulnerability of unsafe behaviors. The research synthesized the results of dynamic and static analysis and found the key control nodes to systematically control unsafe construction behaviors.