摘要：A novel Discrete Wavelet Transform (DWT) based Hidden Markov Module (HMM) for face recognition is presented in this letter. To improve the accuracy of HMM based face recognition algorithm, DWT is used to replace Discrete Cosine Transform (DCT) for observation sequence ex- traction. Extensive experiments are conducted on two public databases and the results show that the proposed method can improve the accuracy significantly, especially when the face database is large and only few training images are available.

摘要：Phase transformation of two-dimensional(2D)nanomaterials can lead to significant changes in electronic and optical properties,which enables the development of novel *** strategies for phase engineering of 2D nanomaterials have drawn considerable attention in recent *** review focuses on the state-of-the-art progress in the phase transformation of 2D nanomaterials and their catalytic ***,the basic concepts of phase transformation and the outstanding electronic and optical properties induced by phase transformation are briefly ***,different strategies for achieving phase transformation are discussed in detail and classified into several types based on their characteristics,including(i)doping,(ii)external fields,(iii)optical irradiation,(iv)strain effect,(v)high-energy particle excitation,and(vi)thermal *** applications of 2D nanomaterials in catalysis based on phase transformation have also been ***,a summary of the technical challenges to phase control in 2D nanomaterials and potential opportunities for developing novel applications is presented.

摘要：The development of low-cost,highly active platinum(Pt)-based electrocatalysts for oxygen reduction reaction(ORR)is crucial for widespread applications of fuel *** effective approach lies in alloying Pt with non-noble transition metals to modulate the physicochemical state of the Pt ***,fundamental challenges remain in understanding the structure-performance relationship due to the complexity of composition,crystal type,and surface structure during the alloying *** this study,we synthesized a series of PtCo bimetallic solid solutions with varying ratios using a liquid-phase synthesis *** exploiting the characteristics of solid solutions,the resulting PtCo bimetallic alloy maintains the face-centered cubic crystal structure of pure platinum,minimizing the complexities introduced during alloying and facilitating mechanism ***,under controlled alloy composition and crystal structure,we investigated the dependence of the electrocatalytic activity for the oxygen reduction reaction on the surface strain of the platinum *** S-PtCo-SNPs cathode designed accordingly endows both proton exchange membrane fuel cell(PEMFC)(2.08 W cm^(−2) at 4 A cm^(−2))and Zn-air battery(ZAB)(143.1 mW cm^(−2) at 214.5 mA cm^(−2))with outstanding performance.

摘要：The global demand for effective skin injury treatments has prompted the exploration of tissue engineering *** three-dimensional(3D)bioprinting has shown promise,challenges persist with respect to achieving timely and compatible solutions to treat diverse skin *** situ bioprinting has emerged as a key new technology,since it reduces risks during the implantation of printed scaffolds and demonstrates superior therapeutic ***,maintaining printing fidelity during in situ bioprinting remains a critical challenge,particularly with respect to model layering and path *** study proposes a novel optimization-based conformal path planning strategy for in situ bioprinting-based repair of complex skin *** strategy employs constrained optimization to identify optimal waypoints on a point cloud-approximated curved surface,thereby ensuring a high degree of similarity between predesigned planar and surface-mapped 3D ***,this method is applicable for skin wound treatments,since it generates 3D-equidistant zigzag curves along surface tangents and enables multi-layer conformal path planning to facilitate the treatment of volumetric ***,the proposed algorithm was found to be a feasible and effective treatment in a murine back injury model as well as in other complex models,thereby showcasing its potential to guide in situ bioprinting,enhance bioprinting fidelity,and facilitate improvement of clinical outcomes.

摘要：Within the domain of homestays,it is imperative to prioritize the augmentation of hosts'pivotal role and the facilitation of pro-environmental behavior among tourists as essential strategies for promoting the sustainability of homestay *** research utilizes homestays in Pingtan Island as a specific example and employs a survey methodology to collect ***,a structural equation model is utilized to analyze the causal relationship between situational factors within homestays and the pro-environmental behavior of tourists,specifically within the context of host-guest *** results of the study indicate that there is a favorable correlation between environmental quality and the interaction between hosts and guests,and visitors'pro-environmental ***,it is worth noting that situational circumstances play a crucial role in shaping the dynamics of host-guest ***,in turn,serves as a mediator for the influence of situational factors on tourists'pro-environmental *** on the aforementioned findings,the present study proceeds to examine the pragmatic ramifications of the research and provides recommendations for prospective areas of investigation.

摘要：Machine learning (ML) has been widely used todesign and develop new materials owing to its low computational cost and powerful predictive capabilities. In recentyears, the shortcomings of ML in materials science have gradually emerged, with a primary concern being the scarcity ofdata. It is challenging to build reliable and accurate ML modelsusing limited data. Moreover, the small sample size problemwill remain long-standing in materials science because of theslow accumulation of material data. Therefore, it is importantto review and categorize strategies for small-sample learningfor the development of ML in materials science. This reviewsystematically sorts the research progress of small-samplelearning strategies in materials science, including ensemblelearning, unsupervised learning, active learning, and transferlearning. The directions for future research are proposed, including few-shot learning, and virtual sample *** importantly, we emphasize the significance of embedding material domain knowledge into ML and elaborate on thebasic idea for implementing this strategy.

摘要：Autologous bone marrow-derived mesenchymal stem cells(BMSCs)have been shown to promote osteogenesis;however,the effects of allogeneic BMSCs(allo-BMSCs)on bone regeneration remain ***,we explored the bone regeneration promotion effect of allo-BMSCs in 3D-printed autologous bone particle(ABP)***,we concurrently printed scaffolds with polycaprolactone,ABPs,and allo-BMSCs for appropriate support,providing bioactive factors and seed cells to promote *** vitro studies showed that ABP scaffolds promoted allo-BMSC osteogenic *** vivo studies revealed that the implantation of scaffolds loaded with ABPs and allo-BMSCs into canine skull defects for nine months promoted *** experiments suggested that only a small portion of implanted allo-BMSCs survived and differentiated into vascular endothelial cells,chondrocytes,and *** implanted allo-BMSCs released stromal cell-derived factor 1 through paracrine signaling to recruit native BMSCs into the defect,promoting bone *** study contributes to our understanding of allo-BMSCs,providing information relevant to their future application.

摘要：The style of Chinese Paintings reflects more obvious artistic characteristics of"beauty of artistic conception"and"beauty of space".However,analyzed fromthe perspective of"beauty of artistic conception",the root of beauty of artistic conception lies in the hierarchical guidance on aesthetic perspective,psychology and thinking,ultimately leading to the continuous widening of the artistic space embodied in Chinese paintings and leaving appreciators extensive artistic *** the artistic style of postmodern paintings emphasizes the abstractness of thinking as the basis and impels intuitive motivation of aesthetic perspective and psychology via the abstractness of aesthetic thinking,thus fully reflecting the postmodernist artistic characteristics of Chinese painting,and meanwhile continuously sublimating the artistic values implied in Chinese paintings.

摘要：Cam profiles play an important part in the performance of cam mechanisms. Syntheses of cam profile designs and dynamics of cam designs are studied at first. Then, a cam profile design optimization model based on the six order classical spline and single DOF(degree of freedom) dynamic model of single-dwell cam mechanisms is developed. And dynamic constraints such as jumps and vibrations of followers are considered. This optimization model, with many advantages such as universalities of applications, conveniences to operations and good performances in improving kinematic and dynamic properties of cam mechanisms, is good except for the discontinuity of jerks at the end knots of cam profiles which will cause vibrations of cam systems. However, the optimization is improved by combining the six order classical spline with general polynomial spline which is the so-called "trade-offs". Finally, improved optimization is proven to have a better performance in designing cam profiles.

摘要：After the 26th Universiade,shenzhen has been striving to build a balanced and harmonious translational eco-environment,and make Public Signs translation play a positive role in the construction of international city ***,shenzhen has formed relative completed systems in beforehand prevention and subsequent punishment in public signs ***,there is also a long way to go to perfect the translation eco-environment construction.