基于深度学习和分层角谱的三维纯相位全息显示

传统的纯相位全息成像方法,大多数依赖于高强度的迭代,耗费时间长,成像质量不高,针对此问题,提出了一种深度学习与分层角谱结合的纯相位全息图生成算法,在快速生成全息图的同时提高了全息图再现质量.通过LeNet网络结构预测三维物体的复振幅信息,降低了计算量,采用精确的角谱算法生成三维物体的高质量纯相位全息图.通过仿真实验证明...     

A 130 nm CMOS low-power SAR ADC for wide-band communication systems

This paper presents a low power 9-bit 80 MS/s SAR ADC with comparator-sharing technique in 130 nm CMOS process. Compared to the conventional SAR ADC, the sampling phase is removed to reach the full efficiency of the comparator. Thus the conversion rate increases by about 20% and its sampling time is relaxed. The design does not use any static components to achieve a widely scalable conversion rate with a constant FOM. The floorplan of the capacitor network is custom-designed to suppress the gain mismatch between the two DACs. The ＇set-and- down＇ switching procedure and a novel binary-search error compensation scheme are utilized to further speed up the SA bit-cycling operation. A very fast logic controller is proposed with a delay time of only 90 ps. At 1.2 V supply and 80 MS/s the ADC achieves an SNDR of 51.4 dB and consumes 1.86 mW, resulting in an FOM of 76.6 fJ/conversion-step. The ADC core occupies an active area of only 0.089 mm2.     

高能炸药的非理想爆轰性能研究

对凝聚态高能炸药的非理想爆轰现象:绕爆边界效应与波面演变、爆轰引发与能量利用效率、反应速率与爆轰波结构,应用理论分析、数值模拟及相应实验结果核对,从压力波形、能量转换、动能输出等,进行了机制和规律方面的初步研究.对高能炸药的非理想爆轰性能研究,提出了今后深入进行精密物理实验、计算和理论分析的建议.     

Formation of Gold and Silver Nanoparticle Arrays and Thin Shells on Mesostructured Silica Nanofibers

Mesostructured silica nanofibers synthesized in high yields with cetyltrimethylammonium bromide as the structure‐directing agent in HBr solutions are used as templates for the assembly of Au and Ag nanoparticles and the formation of thin Au shells along the fiber axis. Presynthesized spherical Au and Ag nanoparticles are adsorbed in varying amounts onto the silica nanofibers through bifunctional linking molecules. Nonspherical Au nanoparticles with sharp tips are synthesized on the nanofibers through a seed‐mediated growth approach. The number density of nonspherical Au nanoparticles is controlled by varying the amount of seeded nanofibers relative to the amount of supplied Au precursor. This seed‐mediated growth is further used to form continuous Au shells around the silica nanofibers. Both the Au‐ and Ag‐nanoparticle/silica‐nanofiber hybrid nanostructures and silica/Au core/shell fibers exhibit extinction spectra that are distinct from the spectra of Au and Ag nanoparticles in solution, indicating the presence of new surface plasmon resonance modes in the silica/Au core/shell fibers and surface plasmon coupling between closely spaced metal nanoparticles assembled on silica nanofibers. Spherical Au‐ and Ag‐nanoparticle/silica‐nanofiber hybrid nanostructures are further used as substrates for surface‐enhanced Raman spectroscopy, and the enhancement factors of the Raman signals obtained on the Ag‐nanoparticle/silica‐nanofiber hybrid nanostructures are 2 × 10⁵ for 4‐mercaptobenzoic acid and 4‐mercaptophenol and 7 × 10⁷ for rhodamine B isothiocyanate. These hybrid nanostructures are therefore potentially useful for ultrasensitive chemical and biological sensing by using molecular vibrational signatures.     

Cover Picture: A Hierarchically Structured Ni(OH)2 Monolayer Hollow‐Sphere Array and Its Tunable Optical Properties over a Large Region (Adv. Funct. Mater. 4/2007)

The fabrication of hierarchically structured Ni(OH)₂ monolayer hollow‐sphere arrays with the shell composed of building blocks of nanoflakelets is reported on p. 644 by Weiping Cai and co‐workers. The morphology can be easily controlled by the synthesis parameters, and the arrays show a tunable optical transmission stop band. Tuning can be achieved by changing the size or morphology of the hollow spheres. Such arrays may have potential applications in optical devices, photonic crystals, and as sensors for gas detection. The fabrication of a hierarchically structured Ni(OH)₂ monolayer hollow‐sphere array with the shell composed of building blocks of nanoflakelets is demonstrated based on a colloidal monolayer and electrochemical deposition. The morphology can be easily controlled by the colloidal monolayer and deposition parameters. Importantly, such monolayer hollow‐sphere array shows a morphology‐ and size‐dependent tunable optical transmission stop band. This stop band can be easily tuned from 455–1855 nm by changing the size of the hollow spheres between 1000 and 4500 nm, and also fine‐adjusted by changing the deposition time. The array exhibits a nearly incident‐angle‐independent position of the stop band that 3D photonic crystals do not possess. This structure may have potential applications in optical devices, photonic crystals, and sensors for gas detection.     

On the profile design and optimization of epitaxial Si- andSiGe-base bipolar technology for 77 K applications. II. Circuitperformance issues

For pt.I see ibid., vol.40, no.3, p.525-41 (1993). The circuit performance issues associated with optimizing epitaxial Si- and SiGe-base bipolar technology for the liquid-nitrogen temperature environment are examined in detail. It is conclusively demonstrated that the notion that silicon-based bipolar circuits perform poorly at low temperatures is untrue. Transistor frequency response is examined both theoretically and experimentally, with particular attention given to the differences between SiGe and Si devices as a function of temperature. ECL and NTL ring oscillator circuits were fabricated for each of the four profiles described in pt.I. The minimum ECL gate delay for a SiGe base is essentially unchanged from its room-temperature value. ASTAP models were used to explore circuit operation under typical wire loading. The results indicate that epitaxial-base bipolar technology offers significant leverage for future cryogenic applications     

A low spur,low jitter 10-GHz phase-locked loop in 0.13-μm CMOS technology

This paper presents a 10-GHz low spur and low jitter phase-locked loop(PLL).An improved low phase noise VCO and a dynamic phase frequency detector with a short delay reset time are employed to reduce the noise of the PLL.We also discuss the methodology to optimize the high frequency prescaler's noise and the charge pump's current mismatch.The chip was fabricated in a SMIC 0.13-μm RF CMOS process with a 1.2-V power supply.The measured integrated RMS jitter is 757 fs(1 kHz to 10 MHz);the phase noise is-89 ...     

星箭包带锁紧装置分离过程动态包络的动力学仿真

包带锁紧装置是世界上各主要运载火箭大都采用的星箭连接和分离机构.随着卫星种类、结构形式的不断变化,卫星对包带装置提出了更高的要求.因此,对包带分离过程中动态包络的研究也显得日益重要.介绍了用ADAMS软件对包带装置分离过程动态包络进行动力学仿真的研究情况,包括建模的方法,模型的ADAMS描述,以及仿真结果与试验结果的比较.     

两栖战车浮心测量方法研究

介绍了两栖战车浮心位置的变化规律，提出了一套基于现有设备的测量方法，并编制了两栖战车浮心位置分析计算软件。     

武器装备的远程智能监测、诊断与维护技术研究

本文介绍了国外对远程智能监测、诊断与维护技术研究、应用现状与特点,建立了针对武器装备远程智能监测、诊断与维护技术的系统结构模型,指出其主要由现场维护诊断、大修基地、远程诊断维护中心三部分构成,并给出了相应的功能模型.其中的重点是:远程智能监测、诊断,便携/嵌入式智能检测前端和快速维修支持与后勤管理.文章最后对该技术应用也进行了讨论.