摘要：当活动断层发生错动时,穿越活动断层的隧道会发生不同程度的破坏。以往的研究大多未考虑隧道埋深、高应力对跨活断层隧道的影响,结果不太能贴切实际。充分讨论了解决深埋隧道抗错断问题的必要性,通过跨活断层隧道模型试验,对比深埋隧道与浅埋隧道的破坏差异,并通过深埋铰接隧道错断试验,分析了隧道外部应力变化、衬砌应变与破坏形态。结果表明:(1)在深埋与浅埋环境下隧道整体变形皆呈“S”型变形,破坏较严重的区域都集中在断层带位置,其中深埋隧道的破坏模式主要以剪切拉伸破坏为主,产生了较大的挤压变形,破坏区域较大,而浅埋隧道主要以剪切破坏为主,在跨断层位置隧道被剪断。(2)在对深埋隧道进行铰接设计后,隧道由“S”型变形转化成“阶梯”型,隧道应变与外部岩体应力峰值得到降低,破坏程度显著减小。(3)通过对隧道衬砌裂纹分布分析,发现无铰接隧道为贯穿型破坏,裂纹影响至整个衬砌,铰接隧道裂纹影响范围约占隧道总长的66.6%,短铰接节段隧道裂纹影响范围约占隧道总长的33.3%,故深埋环境下采用更短的铰接节段对隧道的抗错断效果更佳。(4)通过对比前人研究的浅埋铰接隧道得出,浅埋铰接隧道在断层带外也会发生变形,而深埋铰接隧道破坏主要集中在断层带内位置,因此对于深埋隧道抗错断保护措施应当多集中在断层带位置。

摘要：为了展宽天线的波束宽度，在磁电（ME）偶极子天线的基础上，该文设计出一种低交叉极化宽频带宽波束的新型磁电偶极子天线。通过将振子倾斜弯折，展宽了天线的波束宽度；结合6个寄生振子的对称加载，提高了辐射方向图的一致性。在？型馈电结构基础上，优化天线的振子间距和振子长度，实现了天线58.5%的相对带宽（S11？-10 dB），频带范围为2.3~4.2 GHz；对振子倾斜角度以及寄生振子的参数进行优化，在2.4~4.0 GHz的频带内实现了辐射方向图E面和H面同时达到120＆#176;以上的半功率波束宽度（HPBW）。测试与仿真有较好的一致性，证明了所设计天线不仅具有宽频带宽波束特性，同时在整个频带范围内方向图的一致性得到了极大地提高。

摘要：厦门海底隧道海域隧道地段存在多处风化深槽,岩体主要为全、强风化花岗岩。由于该类岩石强度低,压缩性高,自稳和自承能力差,在隧道衬砌结构的设计和施工工艺的选择方面会遇到一系列特殊的问题。主要通过对天然和重塑强风化花岗岩岩样进行一系列的室内试验,在掌握其基本物理力学特性的基础上,重点对其流固耦合作用下的力学特性进行研究,并建立该类强风化花岗岩的力学模型,通过反演分析对力学模型进行验证。研究成果对风化花岗岩类工程的力学参数取值有重要借鉴意义,对该类岩体中隧道的设计施工具有指导作用。

摘要：设计了一种具有快速瞬态响应能力的低漏失稳压器,利用提出的一种瞬态响应加速(Transient Response Enhancement,TRE)电路,有效地提高了稳压器的瞬态响应速度,而且瞬态响应速度的提高并不增加静态电流.设计的LDO电路采用0.5μm标准CMOS工艺投片验证,芯片面积为0.49mm2.该LDO空载下的静态电流仅23μA,最大带载200mA.在1μF输出电容、200mA/100ns负载阶跃变化时的最大瞬态输出电压变化量小于3.5%.

摘要：提出了一种基于PMA单元结构的超薄宽带完美吸波屏设计方法.该方法将多层拓展带宽的技术与单层多谐振方法有机结合,实现带宽拓展的同时,保持了完美吸波屏结构简单、无集总元件的特点,易于实际加工和应用.以双层三谐振超薄宽带完美吸波屏为例,结合其等效电路,理论上验证了所设计吸波屏的吸波机理,同时验证了方法的有效性.仿真分析该吸波屏具有低雷达散射截面、极化不敏感和宽入射角的特征.仿真和实测结果表明:该吸波屏在厚度为0.01λ的条件下,具有14.1%的半波功率带宽;-3dBsm的雷达散射截面缩减带宽为18.9%,在法线方向的最大缩减量为23 dBsm,在法向±40°内具有较好的雷达散射截面减缩效果.

摘要：Alloyed nanoparticles with core-shell structures provide a favorable model to modulate interfacial interaction and surface structures at the atomic level,which is important for designing electrocatalysts with high activity and ***,core-shell structured Pd3M@Pt/C nanoparticles with binary PdM alloy cores(M=Fe,Ni,and Co)and a monolayer Pt shell were successfully synthesized with diverse *** these,Pd3Fe@Pt/C exhibited the best oxygen reduction reaction catalytic performance,roughly 5.4 times more than that of the commercial Pt/C catalyst used as *** significantly enhanced activity is attributed to the combined effects of strain engineering,interfacial electron transfer,and improved Pt *** functional theory simulations and extended X-ray absorption fine structure analysis revealed that engineering the alloy core with moderate lattice mismatch and alloy composition(Pd3Fe)optimizes the surface oxygen adsorption energy,thereby rendering excellent electrocatalytic *** researches may use this study as a guide on the construction of highly effective core-shell electrocatalysts for various energy conversions and other applications.

摘要：超空泡航行体由于浮力缺失以及尾部滑行力的出现,使航行体具有了尾拍、结构振动和非线性等复杂的运动特征,给超空泡航行体的运动稳定控制设计造成了极大的困难。通过分析作用在超空泡航行体上的流体动力,推导出了超空泡下潜—俯仰面运动数学模型。依据对该模型开环时的系统特性分析,针对开环系统的不稳定性,设计了基于改进型指数趋近率的变结构控制器,并进行了数学仿真。仿真结果表明,该闭环系统响应快速,具有良好的稳定性能。

摘要：Introduction As a kind of high-energy electromagnetic radiation,gamma rays can lead to radiation effect and environmental *** ensure the reliability and safety utilization of gamma radiations in different areas,materials with reliable gamma shielding performances should be *** existing efforts are to use glasses as alternative for the conventional radiation shielding *** a typical window material,glass itself has attracted wide attention due to its unique chemical and physical *** them,lead-based radiation shielding materials are widely used in the field of ionizing radiation protection due to their reliable physical *** the nuclear industry and high energy physics laboratories,different materials can be used for temporary or permanent *** lead-based glass doped with heavy metal oxide PbO is widely used in the field of radiation shielding for a long time with reliable light transmission properties,which facilitates the observation and monitoring of radiation *** this paper,three kinds of transparent silicate glass with different PbO contents were prepared by a high-temperature melting forming *** gamma-rays protection abilities of the three kinds of glass were investigated through experimental and thermotical *** chemical and thermal stability of the glass were also *** addition,the influence mechanism of the structure and performance differences of the three kinds of glass was also *** Analytical pure quartz sand(SiO_(2),purity 99.5%,in mass,the same below),lead monoxide(PbO,purity 99.0%),potassium nitrate(KNO3,purity 99.0%)and sodium nitrate(NaNO3,purity 99.0%)were selected as raw materials for preparation of three kinds of gamma-rays shielding glass materials by a high-temperature melting *** appropriate amount of raw materials was thoroughly mixed and added to 3 L quartz crucible and heated in air at 1200℃.Then the raw materials were melted at 1250℃for 14

摘要：目的:文章从地域文化视角,对滨海城市地域性特征进行分析归纳,探讨基于滨海城市整体风貌和文化内涵的公共设施设计导向。方法:主要以设计学重塑研究的方法开展基础研究,界定相关概念,紧扣滨海特色,总结出城市公共设施在可视层、递进层、内涵层三个层面的塑造方法,并运用案例研究法和3D打印技术,进行滨海城市公共座椅设计实践。结果:依托地域文化开展公共设施设计,从产品的形、色、质、人文关怀入手,为人们提供全新的设计思路,使公共座椅在满足实用功能的基础上,形成更具地域特色的海洋风格。结论:基于地域文化的滨海城市公共设施设计研究,是以城市公共设施为载体,展现城市文化内涵和地域特色的有益尝试,有利于塑造城市形象,营造和谐共生、服务智能的城市发展理念。

摘要：提出了一种具有部分反射特性和吸波特性的共享孔径人工电磁媒质(shared aperture metamaterial,SA-MTM).该媒质由上层斜十字金属图案加载集总电阻的吸波表面、下层开条带缝隙金属面的部分反射表面以及中间介质层构成,吸波表面和部分反射表面在垂直维度上共享了一个物理孔径使该媒质同时实现了吸波特性和部分反射特性.将SA-MTM与天线一体化设计,利用SA-MTM的部分反射表面和天线表面构成的法布里-珀罗(Fabry-Perot,F-P)谐振腔提升天线的增益,利用SA-MTM的吸波表面吸收入射电磁波实现低雷达散射截面(radar section cross,RCS)天线的设计.仿真和实验结果表明,SA-MTM的加载使天线的前向增益在5.57—5.94 GHz的工作带宽范围内都提升了3 d B以上,且天线的后向RCS在2—9 GHz范围内都有明显的减缩.该研究成果克服了天线辐射性能和散射性能无法兼顾的矛盾,对高增益低RCS天线的设计具有重要的指导意义.