摘要：In this paper,three-dimensional(3D)novel hybrid lattice structures with exceptional mechanical properties and energy absorbing performances were proposed,and experimental and finite element simulation comparisons were performed to demonstrate their potential in mechanical ***,different types of basic cubic unit cells were designed for constructing three types of novel hybrid metamaterials,in which stepped circulation of different unit cells was conceived to generate architected ***,quasi-static compression experiments and finite element simulations were performed to study the deformation process and failure mechanisms of as-fabricated hybrid *** energy absorption efficiency,specific energy absorption(SEA)indicators,and energy absorption capabilities of different hybrid lattice metamaterials were compared and *** results show that the deformation mechanisms of novel hybrid lattice were beneficial for generating remarkable elevated densification strain,and the energy absorption efficiency can be tailored by altering the types or sizes of basic unit ***-hardening and bilinear features were also obtained.

摘要：利用直流电机的简化结构和等效电路,推导系统的微分方程和传递函数,在Matlab/Simulink环境下构建直流电机系统的仿真框图,并进行仿真和分析。针对仿真结果提出了优化系统性能的控制器设计方案。利用Simulink设计工具,加入PID控制模块,通过参数整定,设计出符合指标要求的直流电机调速系统控制器。

摘要：以紫薯茎叶为实验材料,采用超声波辅助溶剂法提取其中的总黄酮,考察液料比、提取时间、提取温度、超声功率和乙醇体积分数对紫薯茎叶中总黄酮得率的影响。基于单因素实验,选取四个主要影响因素液料比、超声时间、超声功率、乙醇浓度,应用Box-Behnken响应面实验设计法优化工艺条件。研究表明,紫薯茎叶中总黄酮的最佳提取工艺条件是:液料比18∶1(m L/g)、提取时间50 min、超声功率200 W、乙醇体积分数75%,总黄酮实际得率为3.46%,与预测值3.51%相接近,研究结果为总黄酮的高效提取及紫薯茎叶的综合利用提供了参考。

摘要：目的探索端脑冠状面上中央前、后回与髓突的对应规律。方法选20例正常人脑标本,用广告颜料对各脑回染以不同颜色,作垂直于眦耳线、层厚6 mm的冠状脑切片。选取其中典型层面,通过染色确认中央前、后回,观察对应髓突的数目和方向。结果在所选取的3个典型层面上,中央前、后回对应1支髓突最常见。左侧中央前回所对应髓突分别位于10点和2点方向,右侧中央前回所对应髓突位于12点和2点方向。左侧中央后回所对应髓突分别位于11至11点半、11至12点和9至9点半方向,右侧中央后回所对应的髓突分别位于12至1点、1点半和2点半方向。结论端脑冠状切面上,中央前、后回所对应的髓突在数目和方向上是固定的。

摘要：以某综合楼深基坑工程为例,介绍了深基坑围护方案的选型方法,阐述了基坑施工中的全过程控制、基坑监测以及突发事件的应急处置措施,同时加强对数据的分析,提出了基坑工程应特别重视明水处理的观点。

摘要：为了研究导叶对泵作透平流动状态及漩涡演化规律的影响,基于Omega方法分析泵作透平最优工况下涡结构演化过程。首先以无导叶Z_(0)=0透平为基础,然后为其添加导叶。结果表明:Z_(0)=0时漩涡结构比较紊乱,特别是出口涡相互作用使得其形态结构杂乱无序;Z_(0)=9时出口涡范围较小,漩涡形态及演化较为清晰;导叶内漩涡结构简单,演化过程十分清晰。Z_(0)=0时尾水管内主涡与小涡相互作用使得漩涡结构形态及旋向不明显;Z_(0)=9透平尾水管内螺旋形主涡与叶轮旋向相同,与小涡旋向相反。Z_(0)=9透平尾水管三个截面的切向和轴向速度均比Z_(0)=0有所提高,Z_(0)=9透平P1截面切向动能最大值比Z_(0)=0高96.40%。综上,导叶可以减少漩涡的产生,提升透平流场速度,降低水力损失。研究结果可对导叶式透平的设计运行提供一定的理论基础。

摘要：电热防/除冰是目前防除冰的主流技术,但是电热除冰传统方式采用常规的电热丝、电热片等电阻元件嵌入复材结构后会导致夹芯结构力学性能恶化,同时易结冰部位往往也是电磁波散射的重点部位,而传统电热丝和金属片等电热元件存在会导致其散射特性恶化。通过选用导电织物预浸料作为电阻元件,与复材共固化成型,开展了相关力学性能试验验证,结果表明加入导电织物预浸料的复合材料层压板SK/YJL2#的层间剪切强度和弯曲强度分别是85.7MPa和454.7MPa,SK/YJL1#的层间剪切强度和弯曲强度分别是79.5MPa和519.2MPa,加入导电织物的层板力学性能有一定程度下降,但仍满足使用要求。开展了共固化导电织物层对夹芯结构吸波性能影响验证,结果表明导电织物预浸料阻值在2400~3600Ω/sq范围内,导电织物预浸料与吸波蜂窝制备的共固化夹芯试验件在X波段垂直反射率均小于-10dB。通过调节导电织物预浸料方阻,开展电加热膜与吸波蜂窝结构的阻抗匹配设计,使得吸波性能满足隐身要求,导电织物预浸料、透波预浸料与吸波蜂窝组成的结构可同时兼顾防除冰和隐身要求。

摘要：It was shown that active queue management schemes implemented in the routers of communication networks sup-porting transmission control protocol (TCP) flows can be modelled as a feedback control system. In this paper based on Lyapunov function we developed an optimal controller to improve active queue management (AQM) router’s stability and response time, which are often in conflict with each other in system performance. Ns-2 simulations showed that optimal controller outperforms PI controller significantly.

摘要：TiO_(2)-based materials have been considered as one of most promising alternatives for high-performance Li(Na)-ion batteries because of the low cost,simple composition,easy synthesis,good environmental protection,excellent safety and relatively high specific ***,the inferior electronic conductivity and poor ion diffusion coefficients are the biggest bottlenecks that restrict the popular *** effort has been focused on resolving these problems toward large-scale applications,and numerous significant advances have been *** the present work,a comprehensive overview of structure characteristics,electrochemical reaction mechanism and modification strategies of TiO_(2)-based materials was *** recent advances of various efficient ways for improving conductivity,Li(Na)storage capacity,rate capability and cycle stability are systematically summarized,including surface engineering,constructing composite and element doping,*** TiO_(2)-based materials with novel porous heterogeneous core-shell structures have been regarded as one of the most effective ways to resolve these ***,the future research directions and development prospects of TiO_(2)-based anode materials used in the manufacture of high-performance Li(Na)-ion batteries are *** review can provide important comprehension for the construction and optimization of highperformance of TiO_(2)-based anode materials.

摘要：随着大流量涡轮泵的迅速发展,其叶轮尺寸和转速日益增大,导致涡轮泵本身的耦合振动现象凸显。为保持涡轮泵的平稳运行并降低其振动噪声,本文研究了涡轮泵转子系统的耦合动力学特性。首先,基于简化的涡轮泵转子有限元模型进行分析,发现当转子不同阶频率在Campbell图中相互趋近时,接近重合的区域会发生转向和合并两种耦合特征现象。进一步分析发生耦合特征现象时的转子模态,发现互相耦合的不同阶特征模态会相互影响。接着,采用双自由度系统模拟转子耦合特征现象,分析耦合度、阻尼以及陀螺力矩对其特性的影响。最后,分析双自由度系统耦合动力学特性,发现系统发生转向及合并现象时,其动力响应会发生突变,导致系统耦合振动幅值增大,甚至系统失稳。研究成果可为转子系统安全稳定运行提供理论指导。