摘要：While it is known that mechanical dynamics are influential in neural differentiation for critical processes like neurogenesis or neurodegeneration, studies on neural stem cell therapies usually focus on biochemical interactions rather than mechanical aspects, frequently resulting in low efficacy and unfulfilled potential. Therefore, current studies are attempting to elucidate the effect of mechanical stimulus on neural performance using conventional two-dimensional(2D) planar substrates. Yet, these2D substrates fail to capture the defining three-dimensional(3D) characteristics of the in vivo neural stem cell *** complete this research gap, we synthesized a series of soft and elastic 3D hydrogels to mimic the neural tissue mechanical environment for 3D cell culture, using long-chain polyethylene glycol diacrylate(PEGDA) and gelatin-methacryloyl(Gel MA).By varying the concentration of the polymer, we obtained biomimicking hydrogels with a tensile modulus as low as 10 k Pa and a compressive modulus as low as 0.8 k Pa. The in vitro results demonstrated that Gel MA-PEGDA hydrogels have the high biocompatibility required to support neural cell growth, proliferation, and differentiation, as well as neurite outgrowth. We then studied the effect of mechanical stretching on the behaviors of neural cells and observed that mechanical stretching could significantly enhance neurite extension and axon elongation. In addition, the neurites were more directionally oriented to the stretching direction. Immunocytochemistry and relative gene expression data also suggested that mechanical tension could upregulate the expression of neural differentiation protein and genes, including GFAP and βIII-Tubulin. Overall, this study shows that in addition to the specific mechanical properties of Gel MA-PEGDA that improve neural differentiation towards specific lineages, hydrogel stretching is also a potentially attractive strategy to improve the therapeutic outcomes of neural stem cel

摘要：Tissue curvature has long been recognized as an important anatomical parameter that affects intracellular behaviors,and there is emerging interest in applying cell-scale curvature as a designer property to drive cell fates for tissue engineering *** neural cells are known to undergo dramatic and terminal morphological changes during development and curvature-limiting behaviors have been demonstrated in neurite outgrowth studies,there are still crucial gaps in understanding neural cell behaviors,particularly in the context of a three-dimensional(3D)curvature landscape similar to an actual tissue engineering *** this study,we fabricated two substrates of microcurvature(curvature-substrates)that present a smooth and repeating landscape with focuses of either a concave or a convex *** these curvature-substrates,we studied the properties of morphological differentiation in N2a neuroblastoma *** contrast to other studies where two-dimensional(2D)curvature was demonstrated to limit neurite outgrowth,we found that both the concave and convex substrates acted as continuous and uniform mechanical protrusions that significantly enhanced neural polarity and differentiation with few morphological changes in the main cell *** enhanced differentiation was manifested in various properties,including increased neurite length,increased nuclear displacement,and upregulation of various neural *** demonstrating how the micron-scale curvature landscape induces neuronal polarity,we provide further insights into the design of biomaterials utilizing the influence of surface curvature in neural tissue engineering.

摘要：Aiming at reducing the difficulty of cooling the interior of high-density motors,this study proposed the placement of a water cold plate cooling structure between the axial laminations of the motor *** effect of the cooling water flow,thickness of the plate,and motor loss density on the cooling effect of the water cold plate were *** compare the cooling performance of water cold plate and outer spiral water jacket cooling structures,a high-speed permanent magnet motor with a high loss density was used to establish two motor models with the two cooling ***,the cooling effects of the two models were analyzed using the finite element method under the same loss density,coolant flow,and main *** results were as follows.(1)The maximum and average temperatures of the water cold plate structure were reduced by 25.5%and 30.5%,respectively,compared to that of the outer spiral water jacket motor;(2)Compared with the outer spiral water jacket structure,the water cold plate structure can reduce the overall mass and volume of the *** a 100 kW high-speed permanent magnet motor as an example,a water cold plate cooling system was designed,and the temperature distribution is analyzed,with the result indicating that the cooling structure satisfied the cooling requirements of the high loss density motor.

摘要：In the study of oriented bounding boxes(OBB)object detection in high-resolution remote sensing images,the problem of missed and wrong detection of small targets occurs because the targets are too small and have different *** OBB object detection for remote sensing images,although making good progress,mainly focuses on directional modeling,while less consideration is given to the size of the object as well as the problem of missed *** this study,a method based on improved YOLOv8 was proposed for detecting oriented objects in remote sensing images,which can improve the detection precision of oriented objects in remote sensing ***,the ResCBAMG module was innovatively designed,which could better extract channel and spatial correlation ***,the innovative top-down feature fusion layer network structure was proposed in conjunction with the Efficient Channel Attention(ECA)attention module,which helped to capture inter-local cross-channel interaction information ***,we introduced an innovative ResCBAMG module between the different C2f modules and detection heads of the bottom-up feature fusion *** innovative structure helped the model to better focus on the target *** precision and robustness of oriented target detection were also *** results on the DOTA-v1.5 dataset showed that the detection Precision,mAP@0.5,and mAP@0.5:0.95 metrics of the improved model are better compared to the original *** improvement is effective in detecting small targets and complex scenes.

摘要：为了在超高层建筑结构续建改造设计中减少已建结构的改造工程量,通过附加黏滞阻尼装置有效提高高层建筑在地震作用下的结构耗能,从而降低结构的内力和变形响应。研究了黏滞阻尼伸臂的变形放大原理,介绍了黏滞阻尼伸臂的最优布置方法,并提出了续建改造多状态矩阵,分析了续建改造项目典型驱动因素,总结了集成黏滞阻尼伸臂减震装置的超高层建筑结构续建改造设计策略,最后以工程实例验证该方法的有效性及准确性。结果表明:黏滞阻尼伸臂适用于以弯曲变形为主的超高层建筑结构,变形放大系数可近似为区格的跨度与高度之比,理论放大系数一般为2~3;采用基于阻尼耗能排序不变假定的黏滞阻尼伸臂设计方法,仅需对结构进行一次满布阻尼计算分析即可确定耗能排序及各附加阻尼方案;在以弯曲变形为主的框架核心筒结构中,阻尼伸臂布置在中、高区减震效果最好,距离该位置越远,耗能效果越差,相邻两道伸臂式阻尼提供的附加阻尼比相差约15%;在续建改造项目中布置黏滞阻尼减震系统,黏滞阻尼器提供的附加阻尼并非越大越好,存在使结构综合成本最低的集成减震设计方案;黏滞阻尼伸臂减震集成设计方法在提升结构抗震性能的同时有效降低了结构续建改造成本,具有实际工程价值。

摘要：利用生命周期数据实现设计与运维协同是复杂产品开发和维护的主要模式,也是保证产品稳定、可靠运行的重要途径。在分析当前制造企业面临的挑战与现有制造服务模式研究不足的基础上,提出一种复杂产品智能设计与主动运维“双馈式”制造服务新模式,并设计相应的体系架构。提出并讨论上述新模式的关键技术体系,包括融合物联技术的制造与运维数据主动感知与增值计算、运维过程多源异构数据与知识工程融合的智能化设计、基于产品设计知识与运维过程感知的主动预防性维修等。通过上述技术的实施,可有效促进产品生命周期各阶段数据的交互共享和业务的协同优化,进而可构建一种生命周期数据泛在互联、设计前馈指导运维服务、运维反馈改进产品设计的闭环运作机制,以提升产品设计的智能化和产品运维的预见性。所提新模式和技术体系对生命周期数据驱动的智能制造研究和应用有重要借鉴价值。

摘要：为促进桥梁长寿命设计理论的发展,从桥梁服役寿命及其影响机理出发,总结了现有桥梁长寿命设计的研究现状和面临的主要问题,探讨了未来研究重点和方向。研究结果表明:现行各国规范根据桥梁重要性及其所在公路等级进行桥梁设计寿命的规定,多采用变寿命的设计思路,赋予不同功能、重要程度、更换难度的桥梁构、部件不同的设计寿命;桥梁的寿命取决于其在真实服役环境下的长期性能,包含环境侵蚀作用下的耐久性能、反复荷载作用下的疲劳性能和持续荷载作用下的徐变性能,受服役环境、养护干预和施工过程的影响显著;新建桥梁长寿命技术主要从设计方法和高性能材料展开研究,现有服役寿命和耐久性设计方法主要围绕环境作用、劣化机理、材料性能、施工控制和检查管理等方面,达到了“看似满足”的设计目标,尚未能实现概率水平提升和设计寿命量化,全寿命设计则还停留在理念层面,UHPC、耐候钢、FRP等高性能材料的应用是提升桥梁设计寿命的有效方式;未来应以“明确结构定位,完善性能指标体系,优化结构初始状态,改善服役微环境,控制劣化传递路径”为长寿命设计的基本框架,围绕桥梁结构的长寿基因识别与调控、桥梁微环境全寿命周期演化规律、桥梁服役寿命的全概率量化设计方法等基础理论开展研究,以建立系统的桥梁长寿命设计理论体系。

摘要：菲利普·格拉斯“肖像歌剧三部曲”的后现代主义风格主要体现在以下三个方面:后现代技法与传统舞曲结合,构建“肖像歌剧”的共性音乐主题动机;解构歌剧情节与文本;反叙事的叙述。格拉斯歌剧中后现代主义音乐观的形成缘于他对现代主义音乐的反叛与学术路上受到的多重影响,受到当时以阿尔托和布莱希特为代表的后现代戏剧理论及其创作的影响。

摘要：为探究超高层连体结构在多灾害耦合作用下的设计与安全性能,以苏州超塔为例,开展地震和风耦合作用下的多灾害易损性分析.根据设计资料建立结构有限元模型,分别开展结构在地震作用下以及地震和风耦合作用下的易损性分析,探究结构在多灾害耦合作用下的响应规律.结果表明,地震和风耦合作用下结构联合易损性随着地震动和风荷载强度的增大而增加,且地震动对结构的破坏占主导作用.地震与风耦合作用时结构达到中等破坏、严重破坏和倒塌破坏的概率均比仅地震作用时有所增加.当风速达到40 m/s时,结构在罕遇地震下达到3种破坏状态的概率分别为99.77%、91.56%和46.54%,相比于仅罕遇地震作用下分别提高了1.11%、10.73%和14.65%,相比于一般高层连体结构在同样的灾害耦合作用下分别提高了0.27%、6.26%和14.34%.

摘要：This paper introduces the design and construction of global navigation satellite systems(GNSS)vulnerability simulation,verification,and mitigation *** platform contains five modules:simulation of the signal-in-space environment,simulation of the vulnerabilities in the space segment,signal quality monitoring and data processing,vulnerability assessment and validation,and integrated *** provides a set of integrated simulations of different types of interference in the GNSS signal propagation domain,including electromagnetic interference,atmospheric disturbances,multipath,and interference in the inter-satellite *** paper focuses on the design of the main system modules and testing through an experimental *** results demonstrate both the effectiveness and realism of the modules and overall platform.