摘要：Polyurethane elastomers with covalent adaptable networks(PU-CANs)based on the dynamic urethane bond have attracted remarkable attention owing to their reprocessability,adaptability,and ***,it is still a formidable challenge to achieve excellent dynamics at low temperatures since the urethane bond energy is usually ***,a fluorinated phenolic polyurethane(FPPU)elastomer with CANs based on phenol±carbamate bonds was successfully designed and ***,the effects of fluorine atoms on the mechanical properties,thermal stability,reprocessability,and self-healability,surface free energy,and hydrophobicity of the prepared elastomers were systematically *** FPPU elastomer showed notch-insensitivity,remarkable self-healable efficiency(98%),low dynamic dissociation temperature(60℃),excellent reprocessability,and low surface energy(62 MJ m^(-2))compared with non-fluorinated counterpart phenolic polyurethane elastomer(APPU).Based on the above-mentioned features,FPPU was selected as an elastic substrate to assemble into a triboelectric nanogenerator(TENG)to harvest energy from natural *** TENG exhibited an excellent electrical output performance with a peak open-circuit voltage of 103 V,a peak short-circuit current of 4.7μA and a peak short-circuit charge of 43 *** addition,the TENG possessed high selfcleaning and reprocessing ***,a stretchable and self-healing composite conductor based on FPPU was fabricated for flexible electronic devices.

摘要：模拟和研究了高性能同心金属-绝缘体-金属环的光学特性.通过改变内环折射率ni,内环和外环之间的共振波长和耦合强度可以被大范围调谐,内环和外环的能量分配比也可以被调节.当能量主要分布在内环时,可以有效地抑制损失到波导的能量,从而得到该结构的超高品质(Q)因子.当外环能量较大时,同心双MIM环与波导之间的耦合强度较大,得到该结构的消光比高.提出的同心双MIM环为设计先进的等离子体谐振腔提供了新的视角.

摘要：TiO_(2)is the dominant and most widely researched photocatalyst for environmental remediation,however,the drawbacks,such as only responding to UV light(<5%of sunlight),low charge separation efficiency,and difficulties in recycling,have severely hindered its practical ***,we synthesized magnetically separable Fe_(3)O_(4)@MoS_(2)@mesoporous TiO_(2)(FMmT)photocatalysts via a simple,green,and template-free solvothermal method combined with ultrasonic *** is found that FMmT possesses a high specific surface area(55.09 m2·g−1),enhanced visible-light responsiveness(~521 nm),and remarkable photogenerated charge separation *** addition,the photocatalytic degradation efficiencies of FMmT for methylene blue(MB),rhodamine B(RhB),and tetracycline(TC)are 99.4%,98.5%,and 89.3%within 300 min,*** corresponding degradation rates are 4.5,4.3,and 3.1 times higher than those of pure TiO_(2)*** to the high saturation magnetization(43.1 A·m^(2)·kg^(−1)),FMmT can achieve effective recycling with an applied magnetic *** improved photocatalytic activity is closely related to the effective transport of photogenerated electrons by the active interlayer MoS_(2) and the electron–hole separation caused by the MoS_(2)@TiO_(2)***,the excellent light-harvesting ability and abundant reactive sites of the mesoporous TiO_(2)shell further boost the photocatalytic efficiency of *** work provides a new approach and some experimental basis for the design and performance improvement of magnetic photocatalysts by innovatively incorporating MoS2 as the active interlayer and integrating it with a mesoporous shell.

摘要：为提高骨缺损修复的治疗效果,设计孔隙率为78.8%、70.8%、62.6%和54.4%的梯度多孔钛支架(分别表示为P1,P2,P3和P4),并通过选择性激光熔化技术进行制备。通过模拟和实验方法研究支架的成形性、显微组织、力学性能和渗透性能。模拟结果表明,4种梯度结构的最大等效应力和渗透性分别在569.1~1469.0MPa和(21.7~54.6)×10^(−9)m^(2)范围内,并且P3和P4具有更小的最大等效应力,表明P3和P4具有更高的强度。P3和P4结构支架的显微组织为α'马氏体,屈服强度和弹性模量分别为185.3~250.8MPa和6.1~9.7GPa。相比于P3结构支架,P4结构支架展现出更高的强度和与皮质骨更加匹配的弹性模量,并且其渗透性(18.6×10^(−9)m^(2))在人体骨组织渗透性范围内。因此,具有P4结构支架有望被应用于骨科植入领域。

摘要：本文提出了一种考虑几何非线性的三维连续体结构显式拓扑优化方法.采用移动可变形孔洞(MMV)方法描述结构,具有设计变量少、可与CAD系统无缝集成的优点.此外,由于结构拓扑描述模型与有限元分析模型之间解耦,在有限元分析中可以直接删除孔洞区域的冗余自由度,从根本上解决有限变形拓扑优化因弱单元引起的收敛性问题,同时显著提高了有限元分析的计算效率.数值算例验证了该方法的有效性,结果表明:(1)无论单工况还是多工况载荷作用下,几何非线性对三维结构的最优拓扑构型均具有显著影响;(2)优化后的几何非线性结构可以充分利用大位移和小应变来降低结构柔顺度;(3)几何非线性拓扑优化应评估优化设计的临界失稳荷载,以保证结构服役的安全性.

摘要：To enable real-time flight visualization for junior operators,this paper designs a quadrotor flight system via computer *** aircraft’s three-dimensional model and the flight scene are generated using open graphics library(OpenGL).Attitude angle of the model are calculated using the mathematical model of the *** flight system provides an intuitive way to describe the flight according to real-time data input from the controller.

摘要：目的:在振荡水柱装置研究中,通常通过不同的孔口几何特征来改变能量俘获系统的特性,但其具体流动特性却鲜有报道。本文探讨孔口几何特征(形状、尺寸和开孔率等)对流动特性的影响机制,理解影响能量俘获系统特性的关键因素,研究其对振荡水柱装置水动力特性和波能提取的影响规律,并评估波能提取性能指标的有效性。创新点:1.提出了两点测量法来重构振荡水柱腔室内液面;2.建立了孔口流动特性与孔口几何特征的关系式;3.提出了仅测量腔室内气压即可获得波能提取功率的方法;4.该方法可扩展至非二维矩形腔室及斜向波。方法:1.采用不同尺寸狭缝孔和圆形孔来模拟非线性能量俘获系统;2.通过一系列波浪水槽试验,对振荡水柱装置的水动力特性及波能的提取展开研究;3.采用二次损耗系数和收缩系数来描述孔口往复流动特性,并构建其与孔口几何特征的关系;4.通过两点测量法获取振荡水柱腔室内的准确信息;5.评估压力波动系数和液面放大系数作为振荡水柱装置波能提取性能指标的有效性。结论:1.两点测量法能够重建二维矩形振荡水柱腔室内液面的瞬时空间分布,消除了单点法的测量偏差;2.孔口相对厚度及振荡气流对可被视为薄壁的圆形孔的影响可以忽略不计,但对不能视为薄壁的狭缝孔的影响显著;3.本文提出的二次损耗系数经验公式可用于(1)通过孔口几何尺寸设计其流动特性和(2)通过仅测量腔室内气压来计算波能提取功率;4.用作振荡水柱装置的波能提取性能指标时,压力波动系数比液面放大系数更为可靠。

摘要：Ancient India and Africa had thousands of years of early economic and cultural exchanges based on the basis of spontaneous *** the two sides gradually became colonies of Western countries,they passively changed their original communication methods and modes,and even partly changed *** relationship between India and Africa during this period was linked to the growth and decline of Western powers in the Indian Ocean region,reflecting the internal governance methods and foreign relations concepts of the non-colonial rulers of *** has generally experienced the Portuguese colonial period,the period of hegemony and the period of British *** a large period of time,the sub-stages such as the rule of the Mughal Empire and the British East India Company can also be ***,they present a relatively unique picture of historical exchanges between colonial Indo-African countries or regions.

摘要：The“Belt and Road Initiative”is a major theoretical innovation of major-country diplomacy with Chinese *** is not only a flagship public good for china’s participation in global governance,but also is an important platform for us to build a community of shared *** this initiative,the Chinese Dream of the great rejuvenation of the Chinese nation is linked to the wonderful dreams of the peoples all over the world in pursuit of development and prosperity and has far reached strategic significance.

摘要：目的探究膳食锌摄入和高尿酸血症的相关性。设计横断面研究。研究地点中国湖南省的一家体检管理中心。研究人群共纳入5168例中老年（40岁及以上）研究对象（2697例男性和2471例女性）。结局指标利用经过验证的半定量食物频率调查表来评价膳食锌摄入水平。高尿酸血症定义为男性血尿酸值≥416μmol／L，女性≥360μmol／L。结果高尿酸血症在男性人群中的患病率为22．9％，通过校正年龄、体质指数和能量摄入，和最低组相比，不同膳食锌摄入水平组高尿酸血症的危险度（OR）分别是0．68[95％可信区间（CI）0．45—0．92]，0．63（95％CI0．45-0.89），0．68（95％C10．46—1．00），0．55（95％CI0。35—0．87）（p=0．03）。在女性人群中，高尿酸血症的患病率是10．O％，未校正以及最低校正和多因素校正的OR值均表明膳食锌摄入和高血尿酸血症之间无显著相关性。结论本研究表明膳食锌摄入水平和高尿酸血症在中老年男性中呈负相关，但这种负相关性在女性中并不成立。在男性人群中，这种负相关性在校正年龄、体质指数和能量摄入以及维生素c摄入、乙醇摄入以及营养补充剂摄入等后依然成立。