摘要：Non-axisymmetric endwall is numerically investigated to suppress the secondary endwall flow in a HP turbine suction *** endwall contour is represented by a non-uniform rational B-spline *** solution spaces are designed by the rule of hypercube sampling through variation of nodal radial *** most effective endwall contour is obtained through screening all available samples with surrogate-based *** show that non axisymmetric endwall reduces the turbulence kinetic energy of the passage vortex by 5.5%and the total pressure loss 1.6%.Local heat transfer coefficient is lowered on the afore passage endwall surface with a certain increment on the aft passage *** averaged heat transfer coefficient is reduced.

摘要：High-speed high-resolution analog-to-digital （A/D） conversion demanded by ultra wideband （UWB） signal processing is a very challenging problem. This paper proposes a parallel random projection method for UWB signal acquisition. The proposed method can achieve high sampling rate, high resolution and technical feasibility of hardware implementation. In the proposed method, an analog UWB signal is projected over a set of random sign functions. Then the low-rate high-resolution analog-to-digital convertors （ADCs） are used to sample the projection coefficients. The signal can be reconstructed by simple linear calculation with the sampling matrix, without complying with optimization algorithm and prior knowledge. In other aspects, unlike other approaches that need to utilize an accurate time-shift at extremely high frequency, or design a hybrid filter bank, or generate specific basis functions or work for signals with prior knowledge, the proposed method is a universal sampling approach and easy to apply. The simulation results of signal to noise ratio （SNR） and spurious-free dynamic range （SFDR） validate the efficiency of the proposed method for UWB signal acquisition.

摘要：As future soft robotic devices necessitate a level of complexity surpassing current standards,a new design approach is needed that integrates multiple systems necessary to synchronize the motions of soft actuators and the response of signals,thereby enhancing the intelligence of flexible ***,we propose a liquid crystal elastomer unit cell-based platform that organizes the cells in a group to create expandable *** unit cell behaves like a flexible module that can expand biaxially into a specific,stable,and controllable *** the unit cells in different manners results in an adaptable soft grasper,a half-adder for information processing,and a tunable phononic *** implies a high level of reconfigurability and scalability in both structures and functions by elegantly reassembling the unit *** design strategy has the potential to integrate multiple functions that traditional soft actuators cannot accommodate,providing a platform for developing intelligent soft robotics.

摘要：应用Thermo-Calc热力学计算软件,对GH141合金的平衡析出相和非平衡凝固过程进行了模拟计算。结果表明:GH141合金的平衡析出相有γ、γ′、σ、μ和碳化物(M C、M_6C、M_(23)C_6);合金凝固过程中Mo、Ti元素正偏析比较严重,这会降低合金的初熔点;Al、Ti含量对γ′相的开始析出温度和最大析出量有很大影响;C是碳化物最大析出量的控制元素,且M C、M_6C、M_(23)C_6碳化物的主要富集元素分别是Ti、Mo、Cr。研究结果为合金的成分设计和热处理提供一定的理论依据。

摘要：论文设计了内陆水体中放射性核素连续在线监测系统,并采用蒙特卡罗方法对系统参数进行了优化。论文通过计算^(131)I、^(137)Cs、^(60)Co在不同水体厚度下探测灵敏度,结合系统造价,确定了系统最优化探测体积,并依据四川省水体中天然放射性核素浓度,计算了^(131)I、^(137)Cs、^(60)Co的判断限、探测限和定量限,该结果为内陆水体中放射性核素连续在线监测系统构建提供了技术参考和依据。

摘要：非正交双回转摆臂机构回转范围广、灵活性强,能实现复杂曲面的加工.但该类型回转摆臂机构的主轴轴心偏差会直接影响被加工工件的面形精度.为了有效分析并测量出主轴轴心偏差进而改善机床精度,基于多体系统理论建立了非正交双回转摆臂机构的主轴轴心运动误差模型,此模型包含了回转轴A、B各6项静态结构误差;通过对此运动误差模型进行ANSYS静态仿真分析,获得了回转摆臂机构B在不同回转角度下主轴轴心的运动轨迹;基于Renishaw公司开发的QC10球杆仪测量原理设计了5种不同实验测量路径,验证了主轴轴心运动误差模型可用于非正交回转机构主轴轴心的误差辨识.

摘要：为研究双向螺旋箍筋约束高强蜂窝型钢-UHPC短柱(简称“CS-UHPC”)的轴压性能,揭示箍筋直径、箍筋间距和型钢扩张比等设计参数对该类柱轴压性能的影响,设计并完成了8根轴心受压短柱试验。通过短柱的破坏形态、承载力、荷载-位移曲线、变形能力、刚度、荷载-应变曲线等分析双向高强螺旋箍筋和蜂窝型钢对该类柱的约束增强机理和失效性态。同时,将短柱截面划分为不同的UHPC约束区,计算双向高强螺旋箍筋的有效约束,并将蜂窝型钢等效为两个T形钢分肢的缀板式格构柱,提出CS-UHPC短柱的轴压承载力计算方法。研究结果表明:所有CS-UHPC短柱均发生典型的轴压破坏,由于双向高强螺旋箍筋的约束作用,裂缝发展缓慢,荷载-位移曲线下降段趋于平缓,并维持较高的残余承载力水平,与传统矩形箍筋短柱相比,双向高强螺旋箍筋短柱的轴压承载力增加13.4%、变形系数提高209%、刚度提高11.1%;与实腹短柱相比,扩张比为1.3和1.5的蜂窝腹板短柱的轴压承载力分别增加14.0%和3.8%,变形系数分别提高46.6%和34.4%,刚度分别提高32.3%和23.3%;当双向高强螺旋箍筋直径从4 mm增加至6 mm和8 mm,短柱轴压承载力分别增加17.5%和30.7%,变形系数分别提高15.7%和21.6%,刚度分别提高11.3%和18.6%;当双向高强螺旋箍筋间距从50 mm增加至80 mm和110 mm,短柱轴压承载力分别减少16.0%和14.0%,变形系数分别降低1.8%和17.2%,刚度分别降低14.8%和6.1%。

摘要：磁性粒子成像(MPI)中的磁场拓扑结构及其产生的零磁场能够直接对成像结果的质量造成影响。针对MPI系统的零磁场设计,该文提出一种永磁体与线圈复合的磁场结构。该结构综合永磁体能够直接产生大梯度静磁场的优势及电磁线圈通过控制激励方式精准调控磁场的优势来构造线型零磁场(FFL)。对所设计的磁场拓扑结构首先进行了基于圆形线圈、矩形线圈和矩形永磁体所产生静磁场的比较;然后从磁场空间分布、磁场梯度和磁场均匀性等方面对FFL进行分析;最后通过有限元仿真确定了线型零磁场的平移扫描区域范围,并进行了MPI分辨率及血管成像研究。结果表明,该文所提拓扑结构产生的FFL磁场梯度达到3.075 T/m,磁场梯度均匀性达到98.7%,在扫描区域为30 mm×70 mm×70 mm的空间内的成像分辨率能够达到1 mm。证明了该文所提拓扑结构应用于磁性粒子成像系统的可行性。

摘要：Infectious diseases caused by bacteria are a global threat to the human health. Here, we propose a solvent “irrigation” technique to endow TiO_(2) nanotubes (NTs) to precisely modify with functional nanomaterials, and apply them in constructing a near-infrared (NIR) light controlled drug-delivery system for rapid necrosis of bacteria. In this design, the NIR stimuli-responsive functional shell is located on the external tube wall of TiO_(2) NT;the internal tube wall offers sufficient binding sites for drug loading. Using kanamycin as a model drug, we demonstrate that the reactive oxygen species generated in photocatalysis not only controllably release the loaded drug by scissoring the linked chains, but also effectively compromise bacteria membrane integrity by damaging the cell wall. Benefiting from the damages, antibiotics rapidly enter the bacteria and reach ≥99.9% reduction in Escherichia coli colony within only 2 h. Importantly, such a covalently conjugation-based delivery system can efficiently relieve radical-induced inflammation and cytotoxicity. This study provides an innovative design strategy for engineering delivery systems with tailorable components, enduring stimuli-response by multiple triggers.

摘要：针对旋流气力输送气固多相流场相间作用复杂,缺乏相关流场理论及起旋技术与装备研究等问题,开展散粮水平直管旋流气力输送特性研究。设计导流叶片式起旋器产生旋流场,为维持旋流输送,设计侧向补气继旋装置。搭建试验平台,以小麦颗粒为试验材料,开展针对旋流纯流场与两相流场特性试验研究。结果表明,在旋流纯流场中,入口风速为15~20 m/s时,系统静压损失最小,旋进距离最远;在加入小麦颗粒的两相流场中,入口风速为20 m/s时,旋流管内颗粒分布均匀,静压标准差最小,输送过程更加平稳;散粮旋流气力输送继旋试验中,当主管风速度为20 m/s,补气管风速度为60 m/s,主管与辅管夹角为45°时,流场输送效果较好,系统能耗较小。验证导流叶片式起旋器和侧向补气继续装置设计的合理性。