摘要：In this paper, we present the design and optimization of a side-coupled accelerating structure with an energy switch. The beam parameters are optimized, and the electric field asymmetry in the first cell is analyzed. The new structure we designed has an improvement of 10 times in the accelerating field symmetry. Thermo-mechanical analysis is performed based on the electromagnetic results. The highest temperature is 72.5 ℃ at the nose cone, and the maximal deformation is 73 μm at the outer edge of the coupling cavity.

摘要：A 499.8 MHz SOLEIL-type superconducting cavity was simulated and designed for the first time in this *** higher-order mode(HOM)properties of the cavity were *** kinds of coaxial HOM couplers were *** 4 L-type and 4 T-type HOM couplers,the longitudinal impedance and the transverse impedances were suppressed to below 3 kΩand 30 kΩ/m,*** HOM damping requirements of Hefei Advanced Light Facility(HALF)were *** paper conducted an in-depth study on the radio frequency(RF)design,multipacting optimization,and thermal analysis of these coaxial *** results indicated that under operating acceleration voltage,the optimized couplers does not exhibit multiplicating or thermal breakdown *** cavity has the potential to reach a higher acceleration gradient.

摘要：全球气候变化和城市化进程的持续推进,加剧了极端天气事件频发,采取“基于自然的解决方案”(NbS)缓解高温热浪对城市居民的健康风险具有重要意义。以福州的3种榕属树种——细叶榕(Ficus microcarpa)、高山榕(***)、雅榕(***)和2种常见优势树种杧果(Mangifera indica)和香樟(Cinnamomum camphora)作为研究对象,通过现场实验和生理指标测度等方法,探讨不同树种遮阳环境下的人体生理健康指标变化,以及不同树种遮阳环境对生理指标的影响程度。结果表明:1)相比其他树种遮阳环境,细叶榕遮阳环境下受试者表现为显著低体温和低脉搏的生理特征;2)进入细叶榕遮阳环境后,受试者的体温降低幅度显著大于香樟的遮阳环境,受试者的舒张压降低幅度显著大于杧果的遮阳环境;3)榕属树种遮阳环境下受试者体温降低的概率是香樟遮阳环境下的4.17倍,其中,细叶榕遮阳环境对受试者体温降低的影响显著大于其他树种的遮阳环境。研究结果有助于热带和亚热带城市的园林树种选择和优化,也为城市居民健康出行提供有效避暑建议。旨在揭示微观尺度上绿色空间提供的人类福祉,探讨城市优势树种如何发挥其独特的生态功能。

摘要：In order to suppress the effect of the temperature variation on the wavefront of the laser communication terminal, the secondary mirror support with flexure hinges is designed. The series-wound straight-circle flexure hinge is designed to achieve the maximal variation range of the flexibility or stiffness with the limit of flexure hinges' geometrical size. The position and quantity of the flexure hinges are determined to control the deformation direction of the secondary mirror. In order to search the direction in which the wavefront aberration is minimum, the flexure hinges' parameters are optimized with the system wavefront aberration as the optimization objective. The prototype of the laser communication terminal is constructed and the value of the wavefront aberration is measured under the condition of 20±2°C. Experimental results show that the value of the wavefront aberration root mean square(RMS) is reduced from 0.066λ to 0.042λ, meeting the requirement of RMS less than 1/20λ(λ=632.8 nm). The athermal design method presented in this paper provides a novel way for the athermal design of the small aperture mirror support in off-axis optical systems.

摘要：设计了一种简单而新颖的光学元件。光束经过此元件后,再利用透镜聚焦便可产生无衍射Mathieu光束,且改变衍射元件的参数,Mathieu光束的q值随之改变。利用离散傅里叶方法从理论上导出了该光学系统的Mathieu光束的表达式,采用Matlab模拟了光斑强度。数值模拟和实验结果证实了此元件产生无衍射Mathieu光束的有效性。

摘要：基于傅里叶变换下的菲涅尔衍射理论,对部分相干光产生Mathieu光束进行了理论和实验研究,并利用抽样理论和色散公式推导出Mathieu光束的光强分布表达式.数值模拟了不同传播距离处Mathieu光束的截面光强分布,并设计了实验对模拟结论进行验证.实验采用多波长蓝光LED为光源,利用带有椭圆形孔径的菲林片及轴棱锥得到Mathieu光束.模拟和实验结果均证明部分相干光可以产生Mathieu光束.研究结果对拓展Mathieu光束的应用范围提供了理论依据.

摘要：自然通风条件下室内空气流动及其对热舒适性的影响是住宅设计的重要因素.基于计算流体力学方法,应用Fluent软件,开展了自然通风热舒适性的研究.建立了天津某小区高层住宅建筑中两种户型的计算模型,对夏季典型气候下室内自然通风情况进行了模拟分析.探讨了风向、风速和气温对室内自然通风的速度场和热舒适指数的影响.得出了A型房间的通风效果要优于B型房间的结论.利用数值方法对住宅的自然通风进行模拟,不仅可以评价房间的自然通风效果,而且对于住宅户型的设计具有重要的参考价值.

摘要：提出一种利用环缝精确调控空心光束尺寸的新方法.首先用环缝和旋转毛玻璃产生非相干准单色的环形光源,再经过薄透镜聚焦后产生空间相干度按第一类零阶贝塞尔函数分布的贝塞尔-谢尔模型光场,最后通过轴棱锥对贝塞尔-谢尔模型光场的线聚焦,产生空心光束.通过改变环缝大小控制非相干环形光源尺寸,对贝塞尔-谢尔模型光场的空间相干度分布进行调制,从而精确控制空心光束尺寸.应用广义衍射积分理论以及贝塞尔-谢尔模型描述该光学系统所产生的光场分布.设计相关实验进行验证,理论分析、数值模拟与实验结果相符合.该研究成果对不同尺寸粒子的微操控提供有力的手段.

摘要：地震动荷载作用下,由于“群桩效应”,群桩基础表现出不同于单桩的动力时程响应规律.通过大型振动台模型试验,选取强度均为0.35g人工合成的5002波、5010波,以及典型的Kobe波、El-Centro波,探明嵌岩群桩基础的动力时程响应规律及基频损伤情况.振动台试验结果表明,地震波频谱特性对嵌岩群桩基础的各动力响应参数具有显著影响;El-Centro地震波作用时嵌岩群桩加速度峰值较大,桩顶峰值出现时刻较为滞后;Kobe波作用下,桩顶水平相对位移、弯矩峰值较大,但在El-Centro波时均出现最早;弯矩峰值均没有超出其抗弯极限承载力,且基频未发生明显变化,说明强震作用下群桩基础未发生损伤破坏;因此,可通过不同频谱特性的地震波对嵌岩群桩的抗震性能进行优化设计,并提出相应工程建议.

摘要：计算了X波段(f=9．37GHz)介质和金属膜片混合加载行波加速结构的TM01模和HEM11模的色散曲线,结果表明HEM11模的截止频率比TM01模的低,说明与盘荷波导相比,该种新加速结构单束团的BBU效应得到改善．实验研究优选得到了适用于该种新加速结构的介质(εr 5．812)．采用 MAFIA程序优化设计了模型腔,测试频率与设计的数值吻合得很好．