摘要：Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be changed quickly without redesigning their structures. However, large numbers of long-distance wires are required to connect the programmable metasurface to provide the coded signals from field programmable gate array (FPGA) when controlling the metasurface at a long distance, which is complicated and inconvenient. Here, we propose an infrared-controlled programmable metasurface that can be programmed remotely. The infrared transceiver is able to switch the coding sequences stored in the FPGA controller, thus controlling the voltage on the varactors integrated in the metasurface. Experiment is performed at microwave frequencies, and the measured results verify that the scattering beams of the metasurface sample can be changed remotely by using infrared ray. The proposed infrared-controlled programmable metasurface opens up avenues for constructing a new class of remotely-tuning dynamic metasurfaces.

摘要：本文提出并实现了一种基于人类语音识别的智能超表面,用于对电磁波束进行可编程调控。该智能超表面平台由数字编码超表面、语音识别模块、单片机和数模转换器(DAC)电路组成,可根据预先存储的语音指令对电磁波进行智能控制。所构建的数字编码超表面包含6×6个超级子单元,每个超级子单元由4×4个嵌入了变容二极管的有源数字单元组成。语音识别模块配合DAC和单片机对语音指令进行识别,并生成对应的电压序列来控制超表面。此外,在超表面的设计过程中引入遗传算法,可有效优化超表面相位分布。为了验证智能超表面平台的性能,演示了雷达散射截面积缩减、涡旋波束生成和波束分裂三种典型功能。所提出的方案为调控电磁波提供了一种新的途径,并在电磁和声学通信之间架起了连接桥梁。

摘要：文章针对位于杭州市的某住宅群,结合了软件的使用方法,采用Ecotect建筑性能分析软件对住宅楼室外的日照及太阳辐射、室内的自然采光及眩光特征进行了数值模拟。通过分析建筑群室内外的光环境特征,为该项目的光环境设计方案提供预测、判断及优化。

摘要：创意众包通过招募大众完成产品概念、平面广告等创意设计工作,是获取创意方案的重要手段。但创意众包中参与者通常为非专业设计人员,参与者资源整合不易。为此,提出一种引入均衡探索范式的创意众包进化计算方法,结合设计专家的专业能力与计算机的计算能力整合众包参与者资源。该方法依据设计认知领域中对专家行为的研究成果改进创意众包流程,使众包群体行为更接近专家的设计过程,提升产出的创意方案质量。具体的,利用专家行为的均衡探索范式,包括"持续信息引入"、"结构化探索"、"广度深度均衡探索"、"新老方案均衡探索"等行为准则,计算创意方案的进化适应度,改进进化计算中的基因编码、交叉遗传等操作,引导众包的方案进化。为验证此创意众包方法,实施了一个创意众包实例,招募252名参与者就坐姿矫正产品利用提出的方法产出三代创意方案。实例验证该方法能够扩展众包探索的设计空间,提升众包的创意方案质量。

摘要：高精度时间间隔测量是激光测距、雷达、示波器等多种科学和工程领域中的关键技术。为了提高测量的精确度,使用FPGA器件抽头延迟链实现高精度时间数字转换器(TDC),通过脉冲计数法和抽头延迟线法实现完整时钟周期和非完整时钟周期的测量,并提出一种使用锁相环(PLL)动态调相功能测量延迟链精度的方法,PLL调相精度为15.625 ps,通过多级延迟链级联取平均值的方式减小PLL调相精度引入的测量误差,最小测量误差为0.3125 ps。以紫光同创Logos2系列FPGA芯片实现TDC的设计,仿真验证和板级测试结果证明,使用50级延迟链能实现非完整时钟周期的测量,测量精度为71 ps,TDC时间间隔测量范围小于4.2950 ms。

摘要：The DIA-type Kawai cell possesses a larger volume and a quasi-hydrostatic pressure environment and has been widely used in materials’ synthesis and x-ray diffraction ***, few high-pressure in situ neutron diffraction experiments were performed in the DIA-type Kawai cell because there is no wide window for neutron diffraction and the second-stage anvils and guild block material attenuates the neutron signal *** this work, we tentatively modified the normal DIA-type Kawai cell(MA 2-6-8) into a MA 2-8 mode by removing the six first-stage tungsten carbide *** a consequence, the eight tungsten carbide anvils(Kawai cell) are directly driven by the guide *** results of ex situ and in situ pressure calibration show that the cell pressure can reach 5 GPa with small truncation edge lengths(TEL) of 3 mm even at the load of 300 *** suggests that this MA 2-8 cell may open a new way for high-pressure and high-temperature in situ neutron diffraction.

摘要：This paper aims to address the problem of geometric state control of large-segment steel box girders in offshore hoisting during the construction of large-span bridges. First, the geometric state control indexes of a large-segment steel box girder are determined, such as the manufacturing parameters of the top and bottom slabs, the width of the annular joint, and the support position. Second, the geometric state equations and state transfer matrixes of large-segment steel box girders under different conditions are deduced by taking the mileage and elevation of control points as basic state variables. In application of the geometric state transfer method in the construction control of the Hong Kong-Zhuhai-Macao Bridge, the width of the annular joint and the position parameters for the support of the large-segment steel box girder are predicted precisely. Moreover, the manufacturing parameters of the top and bottom slabs of the steel box girders are calculated reliably. The measured values show that the width of the annular joint is basically the same with the difference of less than 2 mm, the eccentricity of bridge support is less than 20 mm, and the elevation error of the bridge deck is within-10 mm to +15 mm, which meets the construction accuracy. Using the geometric state transfer method, the rapid and accurate installation of the Hong Kong-Zhuhai-Macao Bridge has been realized, demonstrating that the precise control of the geometric state of a steel box girder with ectopic installation and multi-state transition can be realized by using the geometric state transfer method.

摘要：针对涡流阀式变推力发动机,初步建立了设计方法,并设计了长尾管和环形燃气发生器组合的集成式原理样机,开展了考核试验。实验结果表明,设计的原理发动机实现了设计要求;涡流阀式变推力发动机具有存在旋流损失,可实现推力调节比大于压强调节比的工作特性;实验推力调节比达到9∶1。

摘要：针对目前理论模型多注重可行性和影响因素分析,以及方程复杂求解困难的现状,为了得到一个应用性较强的涡流阀变推力发动机推力工程计算方法,借鉴普通固发求解推力原理,结合数值模拟方法,建立了涡流阀变推力发动机的整体模型。结果表明,该模型有一定的精度,模型计算参数与试验和前期理论分析趋势一致,模型简洁并包含主要设计参数,可满足涡流阀变推力发动机的设计需要。

摘要：应用粒子群优化算法研究了固体运载火箭上升段弹道优化设计问题。设计了固体运载火箭上升段飞行程序,构建了固体运载火箭弹道优化设计问题的粒子群算法,通过控制参数改进和引入函数拉伸策略,对算法进行了改进。仿真计算结果表明,粒子群优化算法能有效解决固体运载火箭弹道优化设计问题,优化方案末助推级液体推进剂消耗比原方案减少11.1%,算法收敛速度快,需设置参数少,易于工程实现。可为固体运载火箭弹道优化设计提供理论参考。