摘要：为探测中层大气风场信息,研制了一台具有热补偿特性的大集光率(AΩ)、高信噪比(Signal-to-Noise Ratio,SNR)的地基多普勒非对称空间外差(Doppler Asymmetric Spatial Heterodyne,DASH)干涉仪。针对557.7 nm的氧原子气辉谱线,制定了DASH干涉仪的详细参数和指标。系统采用扩视场和消热差设计,半视场角达到2.815°,集光率为0.09525 cm^(2)sr,系统信噪比在113.75左右,经过热补偿设计后,最终光程差随温度变化(dΔd0/dT)的数值仅为2.224×10^(−7)mm/°C。根据相应参数设计优化了光学系统,前置光学系统和探测器光学系统分别采用像方远心和双远心结构,各项指标均满足探测要求。为验证设计结果,搭建了地基DASH干涉仪实验平台,进行室内以及地基室外实验,最终得到了明显的干涉条纹。上述结果证明DASH干涉仪的系统设计是合理的,系统的信噪比和集光率满足检测要求。

摘要：The human skin has the ability to sense tactile touch and a great range of ***,in prosthetic or robotic systems,it is necessary to prepare pressure sensors with high sensitivity in a wide measurement range to provide human-like tactile ***,we developed a flexible piezoresistive pressure sensor that is highly sensitive in a broad pressure range by using lotus leaf micropatterned polydimethylsiloxane and multilayer *** superposing four layers of micropatterned constructive substrates,the multilayer piezoresistive pressure sensor achieves a broad pressure range of 312 kPa,a high sensitivity of 2.525 kPa^(−1),a low limit of detection(LOD)of<12 Pa,and a fast response time of 45 *** with the traditional flexible pressure sensor,the pressure range of this sensor can be increased by at least an order of *** flexible piezoresistive pressure sensor also shows high robustness:after testing for at least 1000 cycles,it shows no sign of *** importantly,these sensors can be potentially applied in various human motion detection scenarios,including tiny pulse monitoring,throat vibration detection,and large under-feet pressure *** proposed fabrication strategy may guide the design of other kinds of multifunctional sensors to improve the detection performance.

摘要：Backgrou nd Dense titanium(Ti)fusion cages have been commonly used in transforaminal lumbar interbody ***,the stiffness mismatch between cages and adjacent bone endplates increases the risk of stress shielding and cage *** The current study presents a multiscale optimization approach for porous Ti fusion cage development,including microscale topology optimization based on homogenization theory that obtains a unit cell with prescribed mechanical properties,and macroscale topology optimization that determines the layout of framework structure over the porous cage while maintaining the desired *** biomechanical performance of the designed porous cage is assessed using numerical simulations of fusion *** laser melting is employed to assists with fabricating the designed porous structure and porous *** The simulations demonstrate that the designed porous cage increases the strain energy density of bone grafts and decreases the peak stress on bone *** mechanical and morphological discrepancies between the as-designed and fabricated porous structures are also *** From the perspective of biomechanics,it is demonstrated that the designed porous cage contributes to reducing the risk of stress shielding and cage *** optimization of processing parameters and post-treatments are required to fabricate the designed porous *** present multiscale optimization approach can be extended to the development of cages with other shapes or materials and further types of orthopedic implants.

摘要：Bioprinting has been widely investigated for tissue engineering and regenerative medicine ***,it is still difficult to reconstruct the complex native cell arrangement due to the limited printing resolution of conventional bioprinting techniques such as extrusion-and inkjet-based ***,an electrohydrodynamic(EHD)bioprinting strategy was reported for the precise deposition of well-organized cell-laden constructs with microscale filament size,whereas few studies have been devoted to developing bioinks that can be applied for EHD bioprinting and simultaneously support cell *** study describes functionalized alginate-based bioinks for microscale EHD bioprinting using peptide grafting and fibrin incorporation,which leads to high cell viability(>90%)and cell *** printed filaments can be further refined to as small as 30μm by incorporating polyoxyethylene and remained stable over one week when exposed to an aqueous *** utilizing the presented alginate-based bioinks,layer-specific cell alignment along the printing struts could be observed inside the EHD-printed microscale filaments,which allows fabricating living constructs with cell-scale filament resolution for guided cellular orientation.

摘要：The metallurgical properties of the CaO–SiO_(2)–Al_(2)O_(3)–4.6wt%Mg O–Fe_(2)O_(3)slag system,formed by the co-treatment process of spent automotive catalyst(SAC)and copper-bearing electroplating sludge(CBES),were studied systematically in this *** slag structure,melting temperature,and viscous characteristics were investigated by Fourier transform infrared(FTIR)spectroscopy,Raman spectroscopy,Fact Sage calculation,and viscosity *** results show that the increase of Fe_(2)O_(3)content(3.8wt%–16.6wt%),the mass ratio of CaO/SiO_(2)(m(CaO)/m(SiO_(2)),0.5–1.3),and the mass ratio of SiO_(2)/Al_(2)O_(3)(m(SiO_(2))/m(Al_(2)O_(3)),1.0–5.0)can promote the depolymerization of silicate network,and the presence of a large amount of Fe_(2)O_(3)in form of tetrahedral and octahedral units ensures the charge compensation of Al^(3+)ions and makes Al_(2)O_(3)only behave as an acid *** calculation and viscosity measurements show that with the increase of Fe_(2)O_(3)content,m(Ca O)/m(SiO_(2)),and m(SiO_(2))/m(Al_(2)O_(3)),the depolymerization of silicate network structure and low-melting-point phase transformation first occur within the slag,leading to the decrease in melting point and viscosity of the slag,while further increase causes the formation of high-melting-point phase and a resultant re-increase in viscosity and melting *** on experimental analysis,the preferred slag composition with low polymerization degree,viscosity,and melting point is as follows:Fe_(2)O_(3)content of 10.2wt%–13.4wt%,m(CaO)/m(SiO_(2))of 0.7–0.9 and m(SiO_(2))/m(Al_(2)O_(3))of 3.0–*** work provides a theoretical support for slag design in co-smelting process of SAC and CBES.

摘要：The interfacial performance of implanted neural electrodes is crucial for stimulation safety and the recording quality of neuronal *** paper proposes a novel surface architecture and optimization strategy for the platinum–iridium(Pt–Ir)electrode to optimize electrochemical performance and wettability.A series of surface micro/nano structures were fabricated on Pt–Ir electrodes with different combinations of four adjustable laser-processing ***,the electrodes were characterized by scanning electron microscopy,energy-dispersive X-ray spectroscopy,cyclic voltammetry,electrochemical impedance spectroscopy,and wetting *** results show that electrode performance strongly depends on the surface *** scanning overlap along with moderate pulse energy and the right number of pulses leads to enriched surface micro/nano structures and improved electrode *** raises the maximum charge storage capacity to 128.2 mC/cm^(2) and the interface capacitance of electrodes to 3.0×10^(4)μF/cm^(2) for the geometric area,compared with 4.6 mC/cm^(2) and 443.1μF/cm2,respectively,for the smooth Pt–Ir *** corresponding optimal results for the optically measured area are 111.8 mC/cm^(2) and 2.6×10^(4)μF/cm^(2),which indicate the contribution of fner structures to the ablation *** hierarchical structures formed by the femtosecond laser dramatically enhanced the wettability of the electrode interface,giving it superwicking properties.A wicking speed of approximately 80 mm/s was *** optimization strategy,leading to superior performance of the superwicking Pt–Ir interface,is promising for use in new neural electrodes.

摘要：利用InP基共振隧穿二极管(RTD)和加载硅透镜的片上天线设计实现了超过1 THz的振荡器。采用Silvaco软件对RTD模型进行仿真研究,分析了不同发射区掺杂浓度、势垒层厚度、隔离层厚度以及势阱层厚度等对器件直流特性的影响规律。对研制的RTD器件直流特性测试显示:峰值电流密度J_(p)为359.2 kA/cm^(2),谷值电流密度J_(v)为135.8 kA/cm^(2),峰谷电流比PVCR为2.64,理论计算得到的器件最大射频输出功率和振荡频率(f_(max))分别为1.71 mW和1.49 THz。利用透镜封装的形式对采用Bow-tie片上天线和RTD设计的太赫兹振荡器进行封装,测试得到振荡频率超过1 THz,输出功率为2.57μW,直流功耗为8.33 mW,是国内首次报道超过1 THz的振荡器。

摘要：以成兰铁路沿线的桩板墙加固边坡为原型,设计并完成了几何相似比为1:10的地震动模拟振动台试验,并采用HHT时频分析方法分析桩板墙加固边坡地震响应特性,研究结果表明:在加载不同幅值地震波过程中,板式挡墙加固堆积体滑坡的加速度响应表现出明显的高程效应,且在0.3g地震波作用下,滑坡的高程效应最为显著,然后随幅值增大高程效应逐渐减弱。桩板式挡墙的桩身动土压力沿桩身呈非线性分布,其包络线的大小和范围与地震波幅值成正比。桩身最大动土压力出现在嵌入截面处,故需注意该部位的加固设计。桩身的位移响应同样随地震波幅值逐渐增大,耦合位移模式则由以平动为主转变为转动为主。此外,利用基于HHT变换的时频分析方法研究桩板式挡墙加固堆积体滑坡地震稳定性是可行的。通过Hilbert能量谱分析得到地震能量主要集中在2~6 s时域范围内,对应的频域为10~50 Hz。随着输入地震波幅值的增加,滑床和滑体测点的Hilbert能量在时频域上的差异性增大,两者的地震响应差异性显著增大。通过Hilbert边际谱可以识别到滑坡内部的损伤情况,受桩板式挡墙作用滑坡底部的损伤主要发生在坡面,而滑坡中部的损伤主要发生在内部。

摘要：负泊松比超材料由于其优异的力学性能,包括优异的抗剪切性能、抗冲击性能、抗断裂性能、吸能隔振等,在个体防护和抗冲击、减振吸能等领域有着重要的应用价值,从而引起了科学家和工程师们极大的研究兴趣.大多数传统的负泊松比超材料通常基于单元胞体的拓扑结构设计,这类超材料通常不可避免地面临着由其复杂拓扑结构,特别是内凹多边形结构,所带来的设计、制备难题.迄今为止,尽管许多研究人员致力于开发新的负泊松比超结构和材料,但很少有研究能明确指出负泊松比超材料的设计指南或工作流程,更多的研究是基于研究人员的设计灵感和对特定胞元结构的计算机辅助优化.基于此,我们提出了一种受自然启发的负泊松比超材料设计策略,利用天然多孔材料所具有的独特双梯度结构,例如以松质骨和向日葵茎髓心作为生物模型,通过在多孔结构中引入双梯度变化即可得到负泊松比效应,从而制备负泊松比超材料.这种受自然启发的负泊松比超材料设计思路具有一定的普适性,可以扩展到具有常见凸多边形胞元的多孔结构中,基本胞元结构并不局限于特定的内凹多边形等常见的用来构造负泊松比超材料的结构和形状.

摘要：近年来,基于薄膜铌酸锂(TFLN)平台的高性能电光调制器以其小体积、低能量损耗等特点受到广泛关注。本文提出了一种新的具有垂直电极结构的Y波导铌酸锂薄膜电光调制器。研究了调制器的半波电压与缓冲层厚度之间的关系,优化了Y波导的设计参数,最后设计得到插入损耗<5 dB,半波电压<1.5 V的高性能调制器。本文不仅为基于TFLN平台的小型化波导的设计和实现提供了思路,而且为制造高性能和多功能的电光调制器提供了实验依据。