高分子材料导热性能影响因素研究进展

介绍了高分子材料导热性能影响因素研究进展，重点阐释了聚合物基体的结构特性（链结构、分子间相互作用、取向、结晶度等）、导热填料（种类、含量、形态、尺寸等）以及制备方法等对高分子材料导热性能的影响。     

Competitive growth of Al2O3/YAG/ZrO2 eutectic ceramics during directional solidification: Effect of interfacial energy

The microstructure evolution and growth behavior of the Al₂O₃/Y₃Al₅O₁₂(YAG)/ZrO₂ ternary eutectic ceramics during directional solidification were well investigated. During directional solidification of the Al₂O₃/YAG/ZrO₂ ternary eutectic ceramics, {} Al₂O₃ paralleled with {001}ZrO₂ while they did not parallel with {001}YAG at the same time in the competitive growth stage. All of the interfaces parallel to each other finally. The area percentage of the Al₂O₃/ZrO₂ and YAG/ZrO₂ interfaces are 40.4 ± 0.2% and 30.8 ± 0.1%, respectively, higher than that of the Al₂O₃/YAG (28.8 ± 0.2%). The content of Al₂O₃ and YAG phases are 39.9% and 41.1%, respectively, almost double of that of ZrO₂. The interfaces of Al₂O₃/ZrO₂ and YAG/ZrO₂ are shorter and more dispersed than that of the Al₂O₃/YAG. It was found that the interfacial energy of Al₂O₃/ZrO₂ and YAG/ZrO₂ interfaces are lower than that of Al₂O₃/YAG. It can be concluded that interfacial energy plays a decisive role in affecting the crystallographic orientation and interfaces distribution in the Al₂O₃/YAG/ZrO₂ eutectic since the interfaces of Al₂O₃/ZrO₂ and YAG/ZrO₂ with lower interfacial energy can be formed more easily during directional solidification. Therefore, the contents of Al₂O₃/ZrO₂ and YAG/ZrO₂ interfaces are higher. This study can provide theoretical guidance for interface design of multi-phase materials.     

Key-dependent side-channel cube attack on CRAFT

CRAFT is a tweakable block cipher introduced in 2019 that aims to provide strong protection against differential fault analysis. In this paper, we show that CRAFT is vulnerable to side-channel cube attacks. We apply side-channel cube attacks to CRAFT with the Hamming weight leakage assumption. We found that the first half of the secret key can be recovered from the Hamming weight leakage after the first round. Next, using the recovered key bits, we continue our attack to recover the second half of the secret key. We show that the set of equations that are solvable varies depending on the value of the key bits. Our result shows that 99.90% of the key space can be fully recovered within a practical time.     

Rayleigh-Type Wave in A Rotated Piezoelectric Crystal Imperfectly Bonded on a Dielectric Substrate

Propagation characteristics of Rayleigh-type wave in a piezoelectric layered system are theoretically investigated. The piezoelectric layer is considered as a cubic crystal with finite thickness rotated about Y-axis and is imperfectly bonded onto a semi-infinite dielectric substrate. The imperfect interface between the two constituents is assumed to be mechanically compliant and dielectrically weakly conducting. The exact dispersion relations for electrically open or shorted boundary conditions are obtained. The numerical results show that the phase velocity of Rayleigh-type wave is symmetric with respect to the cut orientation of 45。 and can achieve the maximum propagation speed in this orientation. The mechanical imperfection plays an important role in the dispersion relations, further the normal imperfection can produce a significant reduction of phase velocity comparing with the tangential imperfection. Comparing with the mechanical imperfection the electrical imperfection makes a relatively small reduction of phase velocity of Rayleigh-type wave. The obtained results can provide some fundamentals for understanding of piezoelectric semiconductor and for design and application of piezoelectric surface acoustic wave devices.     

Improving EBSD precision by orientation refinement with full pattern matching

We present a comparison of the precision of different approaches for orientation imaging using electron backscatter diffraction (EBSD) in the scanning electron microscope. We have used EBSD to image the internal structure of WC grains, which contain features due to dislocations and subgrains. We compare the conventional, Hough-transform based orientation results from the EBSD system software with results of a high-precision orientation refinement using simulated pattern matching at the full available detector resolution of 640 × 480 pixels. Electron channelling contrast imaging (ECCI) is used to verify the correspondence of qualitative ECCI features with the quantitative orientation data from pattern matching. For the investigated sample, this leads to an estimated pattern matching sensitivity of about 0.5 mrad (0.03°) and a spatial feature resolution of about 100 nm. In order to investigate the alternative approach of postprocessing noisy orientation data, we analyse the effects of two different types of orientation filters. Using reference features in the high-precision pattern matching results for comparison, we find that denoising of orientation data can reduce the spatial resolution, and can lead to the creation of orientation artefacts for crystallographic features near the spatial and orientational resolution limits of EBSD.     

Effects of sintering in a high magnetic field on properties of vitrified bond and vitrified CBN composites

Vitrified bond CBN grinding wheels are being widely used due to their superior performance. Also, advantages of vitrified grinding wheels are high elastic modulus, stable chemical property, and low thermal expansion coefficient. Brittleness and low strength are key factors restricting the development of vitrified bond CBN grinding wheels. In this paper, the sintering in a high magnetic field was innovatively introduced into the manufacturing of vitrified bond CBN grinding wheels, and the effects of sintering in a high magnetic field on properties on vitrified bond and vitrified CBN composites were systematically investigated. Vitrified bond was characterized using three-point bending, scanning electron microscopy, X-ray diffraction. It was observed that microstructure of vitrified bond could be changed, grain orientation could be controlled and average grain size could be decreased in a high magnetic field, while vitrified bond strength could be simultaneously improved. High quality vitrified bond could be obtained by appropriately adjusting the strength and direction of high magnetic field. Results demonstrated that vitrified bond properties were improved when the magnetic field strength was 6?T. In order to highlight the high magnetic field effect on the vitrified CBN composites, the ordinary CBN abrasives and nickel plated CBN abrasives were used respectively. Microstructures, bending strengths of vitrified CBN composites were compared in different high magnetic fields. When the magnetic field strength was appropriate (less than 6?T), the binding characteristic of vitrified bond CBN composites with nickel plated CBN abrasives was greatly improved. The highest bending strength value of vitrified CBN composites was 79.5?MPa in 6?T high magnetic field.     

The correlation between porosity characteristics and the crystallographic texture in extruded stabilized aluminium titanate for diesel particulate filter applications

Porous ceramic diesel particulate filters (DPFs) are extruded products that possess macroscopic anisotropic mechanical and thermal properties. This anisotropy is caused by both morphological features (mostly the orientation of porosity) and crystallographic texture. We systematically studied those two aspects in two aluminum titanate ceramic materials of different porosity using mercury porosimetry, gas adsorption, electron microscopy, X-ray diffraction, and X-ray refraction radiography. We found that a lower porosity content implies a larger isotropy of both the crystal texture and the porosity orientation. We also found that, analogous to cordierite, crystallites do align with their axis of negative thermal expansion along the extrusion direction. However, unlike what found for cordierite, the aluminium titanate crystallite form is such that a more pronounced (0 0 2) texture along the extrusion direction implies porosity aligned perpendicular to it.     

Unraveling the attitudes on entrepreneurial universities: The case of Croatian and Spanish universities

The objective of this paper is to present evidence that there are different types of supportive faculty members. We conducted a case study on a sample of Croatian and Spanish universities by using an already tested ENTRE-U scale for measuring the faculty members' attitudes. These two scenarios are quite different in terms of their innovation systems, economic context and university system. We tested and found no evidence of any statistically significant difference due to the country. These two facts suggest the possible existence of an isomorphic trajectory when implementing entrepreneurial universities regardless the context. University managers should be aware of the existence of three different types of supportive individuals. Each of these groups requires a certain program of human resource development. This shifts the debate to how entrepreneurial universities should manage the tensions arising from the need of some degree of specialization in any of the three roles of the faculty members, namely teaching, researching and transfer of the knowledge stemming from research results.     

汉英双语法庭口译员角色定位的伦理思考

关于汉英法庭口译员的角色定位,从译员的主体性意识角度出发,得出其在庭审过程中担任的有"信息的筛选人","交际的调解人","权力的平衡人"以及"立场的倾斜人"四种不同的角色,这四种角色的交织关系具化了在庭审过程中译员所展现出来的主体性意识。同时也不能回避其自身的伦理意识问题。以切斯特曼的五种翻译伦理模式为导向,结合相关真实庭审语料分析,对汉英双语法庭口译员的角色定位进行客观的伦理评价,得到如下发现:1)译员主体性意识下的汉英双语法庭口译员的四种角色符合翻译伦理要求;2)汉英双语法庭口译员的角色定位并不是一层不变的,只要符合翻译伦理要求,译员角色的定位可以有新的突破和发展。     

Influence of market orientation on performance: the moderating roles of customer participation breadth and depth in new product development

ABSTRACT

With a greater number of B2B firms integrating customers into the new product development (NPD) process, how to utilize customer involvement in NPD is an important decision because it may be a double-edged sword carrying both bright and dark sides. Utilizing a sample of 193 B2B firms across various industries, we validate previous research that suggests market orientation positively influences NPD performance and subsequently examine how this relationship may either be enhanced or diminished contingent upon how customers are utilized in the NPD process. The results show that the market orientation–NPD performance relationship is enhanced by having customers participate in a greater number of activities throughout NPD (customer participation breadth) and diminished when customers are involved at deeper levels (customer participation depth). This research suggests that the exact involvement of customers is a critical decision and has clear implications for the dialogues about customer involvement and management of customer relationships.