3D打印PSI导板在膝关节单髁置换术中的应用研究

探讨分析3D打印PSI导板在膝关节单髁置换术中的临床应用效果。方法 本课题拟选取2022年至2023年我院行膝关节单侧全髋关节置换手术的60名患者,将其分为两组,即对照组:1)行 UKA手术,2)进行常规影像学检查;观察组应用3D打印PSI截骨导板辅助UKA术,对比两组各项指标情况。结果:两组患者的术后并发症发生率、并发症发生率均明显低于对照组(P<0.05)。手术后,实验组 HSS得分降低,HKA角度增大,与对照组比较,具有显著性(P<0.05)。治疗组的术后并发症发生率为20.00%,治疗组为6.67%,比较有显著性(P<0.05)。结论:3D打印前交叉韧带导向器在膝关节单侧关节内固定中的作用比较明显,值得推广应用。

Nonlinear time-reversal interferometry with arbitrary quadratic collective-spin interaction

Atomic nonlinear interferometry has wide applications in quantum metrology and quantum information science.Here we propose a nonlinear time-reversal interferometry scheme with high robustness and metrological gain based on the spin squeezing generated by arbitrary quadratic collective-spin interaction,which could be described by the Lipkin–Meshkov–Glick(LMG)model.We optimize the squeezing process,encoding process,and anti-squeezing process,finding that the two particular cases of the LMG model,one-axis twisting and two-axis twisting outperform in robustness and precision,respectively.Moreover,we propose a Floquet driving method to realize equivalent time reverse in the atomic system,which leads to high performance in precision,robustness,and operability.Our study sets a benchmark for achieving high precision and high robustness in atomic nonlinear interferometry.

10000 PSI压力管道建造过程及隐患分析

本文探讨了10000PSI压力管道建造过程及潜在的安全、质量隐患,包括施工安全、材料质量、设计参数和操作维护等方面。

Achieving 1.2 fm/Hz^(1/2)Displacement Sensitivity with Laser Interferometry in Two-Dimensional Nanomechanical Resonators:Pathways towards Quantum-Noise-Limited Measurement at Room Temperature

Laser interferometry is an important technique for ultrasensitive detection of motion and displacement.We push the limit of laser interferometry through noise optimization and device engineering.The contribution of noises other than shot noise is reduced from 92.6%to 62.4%,demonstrating the possibility towards shotnoise-limited measurement.Using noise thermometry,we quantify the laser heating effect and determine the range of laser power values for room-temperature measurements.With detailed analysis and optimization of signal transduction,we achieve 1.2 fm/Hz^(1/2)displacement measurement sensitivity at room temperature in twodimensional(2D)Ca Nb_(2)O_(6)nanomechanical resonators,the best value reported to date among all resonators based on 2D materials.Our work demonstrates a possible pathway towards quantum-noise-limited measurement at room temperature.

Landslide Characterization Using Satellite Interferometry (PSI), Geotechnical Investigations and Numerical Modelling: The Case Study of Ricasoli Village (Italy)

Ricasoli is a village located in a morphological high in the Upper Arno river Valley (Tuscany), an area historically subject to widespread slope instability phenomena. This morphological high and the surrounding slopes result to be affected by numerous landslides, which cause the retreat of the escarpments surrounding the village, involving infrastructures and buildings. To better understand the behaviour of these phenomena a complete characterization, in terms of kinematics, mechanical properties and triggering conditions, of the landslides has been carried out. With this aim several boreholes, equipped both with inclinometer and piezometers, have been drilled and a number of samples have been collected and analysed. In addition to the traditional analysis, the radar satellite interferometry has been used to evaluate the evolution of the landslides and its correlation with rainfalls;furthermore a finite difference numerical modelling has been carried out to investigate the kinematics of the landslides and the deformation pattern.

Monitoring Landslide-Induced Displacements with TerraSAR-X Persistent Scatterer Interferometry (PSI): Gimigliano Case Study in Calabria Region (Italy)

This work provides a detailed detection of landslide-induced displacements at local scale on Gimigliano site (Italy), by means of PSI (Persistent Scatterers Interferometry) analysis, exploiting TerraSAR-X data acquired in November 2010-October 2011. In February-March 2010, several landslides affected Gimigliano, following high-intensity precipitation, and causing damages to structures and roads. In order to assess any spatial and temporal patterns of deformation, the present X-band PS data were compared with historical motion rates derived from ERS1/2 and ENVISAT satellites, and with geological and geomorphological evidences resulting from auxiliary data such as landslide databases and orthophotos referred to different dates, finally validated with recent field checks. The PSI analysis of the historical ground motion rates highlighted that the modern built-up area located downhill was already affected by surface ground deformation since 1993. A significant enlargement of the instability phenomena is detected across time. The recent PS data analysis and the in situ observations permitted us to accurately update the ground movements in the investigated site: their evidence allowed assessing a reactivation of the large deep-seated landslide zone on which the new urbanized area had built-up, with an average deformation rate of about 8 - 9 mm/yr. The higher instability phenomenon is affecting the eastern part of Gimigliano old village, with a mean displacement velocity reaching up values of -30 mm/yr, in the radar temporal acquisition of only 10 months. These outcomes can be taken into account for further hazard-reduction analysis and to support risk mitigation design within the investigated area.

Multi-Temporal Analysis of Land Subsidence in Toluca Valley (Mexico) through a Combination of Persistent Scatterer Interferometry (PSI) and Historical Piezometric Data

The Toluca Valley Aquifer (TVA) is considered one of the most overexploited aquifers in Mexico because of the high rate of groundwater extraction for supplying urban and industrial water to Mexico City and Toluca City, which causes land subsidence in urban and suburban areas. In this paper, we propose a multi-temporal analysis that uses persistent scatterer interferometry (PSI) method to evaluate the subsidence processes in Toluca Valley. The PSI results revealed differential movements of the ground of as much as 83 mm/year. A spatial variation of PSI results was identified with respect to previous studies using the conventional Din SAR methodology. The spatial distribution and density suggested the possibility of an expanding trend of subsidence process at north, northeast and east of the TVA, which corresponds to the region with the highest density of pumping wells for industrial and agricultural use.

Intensity-Dependent Dipole Phase in High-Order Harmonic Interferometry

High-order harmonics are ideal probes to resolve the attosecond dynamics of strong-field recollision processes.An easy-to-implement phase mask is utilized to covert the Gaussian beam to TEM01 transverse electromagnetic mode,allowing the realization of two-source interferometry of high-order harmonics.We experimentally measure the intensity dependence of dipole phase directly with high-order harmonic interferometry,in which the driving laser intensity can be precisely adjusted.The classical electron excursion simulations reproduce the experimental findings quite well,demonstrating that Coulomb potential plays subtle roles on movement of electrons for harmonics near the ionization threshold.This work is of great importance for precision measurements of ultrafast dynamics in strong-field physics.

Wide-spectrum optical synthetic aperture imaging via spatial intensity interferometry

High resolution imaging is achieved using increasingly larger apertures and successively shorter wavelengths.Optical aperture synthesis is an important high-resolution imaging technology used in astronomy.Conventional long baseline amplitude interferometry is susceptible to uncontrollable phase fluctuations,and the technical difficulty increases rapidly as the wavelength decreases.The intensity interferometry inspired by HBT experiment is essentially insensitive to phase fluctuations,but suffers from a narrow spectral bandwidth which results in a lack of effective photons.In this study,we propose optical synthetic aperture imaging based on spatial intensity interferometry.This not only realizes diffraction-limited optical aperture synthesis in a single shot,but also enables imaging with a wide spectral bandwidth,which greatly improves the optical energy efficiency of intensity interferometry.And this method is insensitive to the optical path difference between the sub-apertures.Simulations and experiments present optical aperture synthesis diffraction-limited imaging through spatial intensity interferometry in a 100 nm spectral width of visible light,whose maximum optical path difference between the sub-apertures reaches 69λ.This technique is expected to provide a solution for optical aperture synthesis over kilometer-long baselines at optical wavelengths.

Measurement of Shear Stress Acting on Flat Plate Using Oil Film Interferometry

Measurements of frictional resistance play an important role in engineering practice. There are several types of air resistance acting on an aircraft, for example. One of them, frictional resistance, accounts for half of the air resistance. Oil film interferometry is one of methods for measuring the frictional resistance. Oil dropped on an object is thinly stretched by the frictional resistance. The bright and dark fringe pattern is generated when monochromatic light is applied to the oil film. The gradient of the oil thickness decreases with the lapse of time, and thus the spacing between neighboring the dark lines increases. The rate at which the spacing increases is proportional to the frictional resistance. In this study, the frictional resistance acting on a small area on a plate was measured and compared with the theoretical value. As a result, these results qualitatively agree well with each other.

利用InSAR形变反演滑坡滑面运动特征——以汶川县布瓦村滑坡为例

当前滑坡滑面运动特征获取多采用接触式手段,费时费力、成本高昂,且仅能获取稀疏点位滑面运动状态。因此,本文提出一种非接触式滑坡滑面运动特征获取方法,其基本思路是:基于位错理论建立滑坡表面形变与滑面运动间的关系模型,同时引入滑面运动平滑约束条件,最终以InSAR等技术获取的地表形变为约束,反演获得滑面运动特征。本文选择四川省汶川县布瓦村滑坡作为研究对象,以时序InSAR技术获取的滑坡坡面升降轨形变数据为约束,基于发展的理论方法反演获得布瓦村滑坡滑面几何与运动学参数,并结合野外勘查、Lidar观测以及模型残差较好地验证了反演结果的可靠性,其中反演升降轨模型残差仅3.1 mm·a^(-1)和3.4 mm·a^(-1)。反演结果显示,布瓦村滑坡滑面位于坡表以下平均~15.0 m深度处,滑面整体以沿坡向运动为主,最大运动量级达~80 mm·a^(-1),同时在坡体西侧中下部发现微量的垂直坡向运动。本文提出方法可方便、快速的获取空间连续的滑坡滑面运动特征,为滑坡灾害预警和失稳风险评估提供更为直接可靠的科学参考。

TIMSS 2019中PSI任务分析及启示

国际数学与科学趋势研究(the Trends in International Mathematics and Science Study,简称TIMSS)是针对中小学教育中的数学和科学开展的规模最大、最全面的评价。其中,TIMSS 2019开发了额外的“问题解决和探究任务”(Problem Solving and Inqui-ry tasks,简称PSI任务)项目,旨在深入了解如何使用基于数字化的互动评估项目来捕捉学生的反应,进而对学生的数学与科学高阶能力进行更有效的评价。针对TIMSS 2019中PSI任务的分析,对我国科学教育评价体系的完善以及后续科学教学具有重要的现实意义。

基于PSI的纵向联邦学习数据隐私安全技术

联邦学习系统较好地解决了“数据孤岛”问题,也在一定程度上保护了私密训练数据,然而目前联邦学习仍然存在一些隐私安全风险。首先根据联邦学习系统的不同运行阶段归纳总结了其中的隐私安全威胁,并给出了一些解决办法;其次重点讨论了纵向联邦学习系统中的样本对齐问题,讨论和分析了现有的私密求交的基本方法,提出了一种基于零知识证明的私密求交方法并给出了一些改进方向;最后,基于该私密求交方法,讨论了该方法如何与其他方法结合进行联邦学习隐私保护。

面向干涉包裹相位的多等级噪声抑制网络

包裹相位是激光干涉测量获取相位信息的前提,为了减小测量过程中噪声对包裹相位条纹的干扰,提高重构图像的质量,提出了一种非对称融合非局部边缘提取神经网络(Asymmetric Fusion Non-Local and Verge Extraction Neural Network,AFNVENet)。该网络在FFDNet基础上,设计了非对称融合非局部块和边缘提取模块,通过融合不同级别噪声特征及反向引导去噪过程,在有效抑制多等级噪声的同时,保留了更多的图像细节信息。选择带有乘性散斑与加性随机噪声的包裹相位数据集用于训练,通过消融实验和对比实验结果表明,AFNVENet算法对不同等级的噪声都具有更好的噪声滤除效果,当噪声标准差在[0,2.0]范围内变化时,去噪后的PSNR、SSIM和SSI均值分别达到24.88 dB,0.97和0.95。此外,通过进一步解包裹结果表明,AFNVENet去噪后的解包裹相位均方根误差均值比SCAF,NLM,KSVD和DnCNN分别减小了87%,73%,79%和36%,验证了该方法的可行性。AFNVENet方法在抑制噪声时具有较好的鲁棒性,可适用于不同干涉测量环境下多等级噪声的包裹相位信息恢复。

大视场白光干涉测量系统及性能研究

基于国产化的2倍迈克尔逊型干涉物镜组,优选配置0.5倍适配镜,对白光LED照明光源进行带通滤波参数的仿真估算和实验性能比较,构建了整套大视场白光干涉精密测量装置系统并进行了实验测试,通过白光干涉轴向响应实验曲线确定了中心波长。实验结果表明:通过光谱滤波获得了较为理想的白光干涉轴向响应曲线;系统的水平最大视场达到了14 mm;高度为2.04μm和20.43μm的标准台阶样品的测量结果分别为2.05μm和20.47μm,10次测量重复精度(标准差)分别为12 nm和16 nm。对粗糙度样板、微机电系统传感结构和半导体晶圆膜层进行了实测,表明所研制的系统装置在三维光学无损精密检测领域的应用具有可行性。

联合SAR影像相位和幅度信息的多形变量级滑坡监测——以金沙江白格滑坡为例

近年来,雷达遥感被广泛用于提取滑坡表面的高精度形变信息,所用技术包括基于相位的干涉测量和基于幅度的像素偏移量追踪;然而,大型复杂滑坡的形变量在时间演化以及空间分布上都存在较大差异,单一雷达遥感手段难以实现滑坡形变的全面监测。该文在雷达遥感形变探测能力分析的基础上,提出联合SAR(synthetic aperture Radar)影像的相位和幅度信息进行滑坡的全过程监测。以2018年发生的金沙江白格滑坡为例,基于2014—2021年Sentinel-1数据和2014—2018年ALOS-2数据,联合时序InSAR(interferometric SAR)分析和时序像素偏移量追踪(pixel offset tracking,POT),获取滑坡灾前灾后时序形变。结果显示白格滑坡灾前后缘的年平均速率在20 mm/a,主滑坡区2014年12月—2018年7月形变量可达45 m左右;灾后滑坡逐渐向后缘扩张,年平均形变速率可达200 mm/a,已经威胁到部分民房。2种方法的联合可以实现大型复杂滑坡的时空维多形变量级提取。

基于地基测量数据的月球DRO轨道定轨精度分析

针对地月空间DRO探测,基于中国深空探测任务的现有测量条件,仿真分析月球DRO轨道探测器定轨预报精度。采用批处理定轨方法,选择以地球为中心天体进行轨道积分,并增加了月球非球形引力摄动。计算分析表明,在目前的测量条件下,2天短弧测距单独定轨精度为km量级,速度精度优于3cm/s,预报7天三维位置最大差异为数10km量级,速度差异小于6 cm/s;测距联合VLBI定轨精度为百米量级,速度精度优于0.4 cm/s,预报7天三维位置最大差异为千米量级,速度差异小于2cm/s,VLBI数据的加入能显著提高DRO短弧定轨预报精度。5天长弧测距单独定轨精度优于1km,速度精度优于1cm/s,预报7天三维位置最大差异小于2km,三维速度最大差异小于1cm/s,增加定轨弧长对测距数据单独定轨预报精度有显著提高。

高洁净度超光滑非球面的自动化干涉检测方法

为了实现应用于高能激光等领域对表面洁净度有着极高要求的超光滑非球面检测,排除检测人员带来的洁净度与空气扰动的影响,研究了高洁净度超光滑非球面的自动化干涉检测方法。通过建立补偿干涉法非球面失调量与波前像差之间的灵敏度矩阵,实现利用波前像差求解被测非球面失调量。以理想干涉系统的离焦、彗差与像散为优化目标,进行反馈控制,实现被测非球面的自动化调整,进而实现高洁净度超光滑非球面的自动化干涉检测。实验结果表明,在干涉图可测范围内,利用灵敏度矩阵通过几步迭代即可实现非球面失调量的收敛。结合Stewart六自由度调整台,分别实现2μm精度的平移误差调整、2"精度的光轴自动化对准,最终完成被测非球面的精密调整,实现高洁净度超光滑非球面的自动化干涉检测。采用灵敏度矩阵与六自由度调整的非球面自动化干涉检测方法可实现被测非球面失调量的快速求解与自动调整,降低人员和环境带来的扰动影响,提高了非球面的检测速度,并实现了高洁净度超光滑非球面的自动化干涉检测。

激光回馈精密测量技术及应用

介绍了激光回馈干涉的理论模型,阐述了激光回馈测量灵敏度高、装置结构简单、可自准直、能够对非合作目标进行精密测量的技术特点。分析了激光回馈测量相较传统干涉测量的优势,探讨了激光回馈测量技术在工业和科研领域中的应用方向,包括位移、角度、振动、绝对距离测量等,指出利用频率复用、偏振复用、(准)共路等技术可提高回馈测量的实际应用性能。最后展望了激光回馈技术的发展前景,为推动回馈技术的广泛应用提供借鉴。

基于主成分分析和VU分解法的两步随机相移算法

为了平衡相位计算的精度和速度,大量的两步随机相移算法发展起来。提出了一种基于主成分分析和VU分解法的快速、高精度两步随机相移算法。首先,采用两步主成分分析法对经过滤波的两幅相移干涉图进行计算求出迭代初始相位;然后,利用没有滤波的两幅相移干涉图进行VU分解、迭代求出最终相位。通过模拟和实验结果对比表明:与四种性能良好的两步随机相移算法相比,对于不同的条纹类型、噪声、相移值及条纹数量,提出的算法综合性能最好,其精度最高,有效相移范围和有效条纹数量范围最大,当干涉图像素数为401 pixel×401 pixel时,提出的算法仅比格兰-施密特正交化法和两步主成分分析法多花费0.035 s。在理想情况下,提出的算法可以得到完全正确的结果。如果需要得到较高精度,最好能够提前抑制噪声,同时设置相移值远离0和π,条纹数量大于2。主成分分析和VU分解法无需滤波,花费近似非迭代算法的时间获得迭代算法的精度,其打破了迭代算法花费时间较多的限制,适合高精度光学在线检测,有广泛的发展前景。