基于LiCl盐浓度梯度的固态纳米孔DNA分子检测

针对生物分子通过固态纳米孔的速度过快所引起的低时间分辨率问题,采用氯化锂(LiCl)盐溶液和盐浓度梯度相结合的方法来提高检测过程中信号的时间分辨率.通过在氮化硅薄膜上制备固态纳米孔,并在纳米孔两端施加LiCl盐浓度梯度进行DNA分子检测,发现DNA分子信号频率随LiCl盐浓度梯度的增加呈指数递增趋势,10倍浓度梯度下的...     

基于模块化多电平拓扑的谐振变换器设计

在海洋科学研究和海洋观测领域中,水下系统的供电方式大多是岸基负高压传输到海底接驳设备。海底接驳设备中的功率变换器将岸基电源的数千伏至十几千伏的直流高压转换成低压375 V供海底设备供电。针对变换器高电压输入、宽电压范围输入及输入输出电压变比大的技术难点,提出了模块化多电平的LLC谐振变换器拓扑结构,文中对变换器进行了模型搭建和电路仿真,并完成了一台40 kW工程样机的设计,最后根据仿真和实验结果验证了模块化多电平谐振变换器工作原理的正确性及可行性。     

914nm LD端面抽运Nd:YVO4 100kHz皮秒再生放大器

采用Nd:YVO4晶体带内抽运波长914nm,降低激光二极管(LD)连续抽运时晶体的热负荷和端面热应力,提高高重复频率Nd:YVO4皮秒再生放大器输出性能。研究分析了普克尔盒加压脉宽对工作频率为100kHz的Nd:YVO4再生放大器输出脉冲稳定性的影响,在吸收914nm抽运功率为68W,通过控制普克尔盒加压脉宽,实现了对单脉冲能量为1nJ、脉宽为5.7ps、频率为42.7MHz的全固态Nd:YVO4半导体可饱和吸收镜(SESAM)锁模种子激光脉冲的稳定的100kHz皮秒激光再生放大,输出平均功率为21.2W。     

一种高速高精度比较器的设计

数模转换器(ADC)作为片上集成系统SOC的关键模块,直接决定着SOC的性能.比较器更是在ADC中尤其是逐次逼近型(SAR)ADC中起着非常重要的作用.在SAR ADC中,比较器决定着ADC的速度、精度和功耗等指标,因此说,比较器是SARADC的核心电路.设计了一种应用于12 bit、1 Ms/s采样率SAR ADC的比较器,并提出了估算输入失调电压的新方法.仿真结果表明,在1.8 V,UMC18混合信号工艺下,速度能达到20 MHz,增益达到77 dB,有效分辨的最小电平达到400μV,第一级等效输入噪声仅为94μV.在每级电路存在20 mV失调电压的情况下,该比较器仍能将失调电压有效消除.     

1.8 V音频Σ-Δ调制器设计与实现

介绍了一种适用于数字音频应用的16位8 kHz Σ-Δ调制器,该电路采用单环三阶、单比特量化形式;为适应较低电压,采用带密勒补偿的两级运放.仿真结果显示,调制器在128倍过采样率时,带内信号信噪比可达到102.6.该电路采用UMC 0.18 μm混合信号工艺实现,工作电压为1.8 V,芯片版图面积为1.3 mm×1.3 mm.     

Uncertainty Quantification for Modern High-Dimensional Regression via Scalable Bayesian Methods

Tremendous progress has been made in the last two decades in the area of high-dimensional regression, especially in the “large p, small n” setting. Such sample starved settings inevitably lead to models which are potentially very unstable and hence quite unreliable. To this end, Bayesian shrinkage methods have generated a lot of recent interest in the modern high-dimensional regression and model selection context. Such methods span the wide spectrum of modern regression approaches and include among others, spike-and-slab priors, the Bayesian lasso, ridge regression, and global-local shrinkage priors such as the Horseshoe prior and the Dirichlet–Laplace prior. These methods naturally facilitate tractable uncertainty quantification and have thus been used extensively across diverse applications. A common unifying feature of these models is that the corresponding priors on the regression coefficients can be expressed as a scale mixture of normals. This property has been leveraged extensively to develop various three-step Gibbs samplers to explore the corresponding intractable posteriors. The convergence of such samplers however is very slow in high dimensions settings, making them disconnected to the very setting that they are intended to work in. To address this challenge, we propose a comprehensive and unifying framework to draw from the same family of posteriors via a class of tractable and scalable two-step blocked Gibbs samplers. We demonstrate that our proposed class of two-step blocked samplers exhibits vastly superior convergence behavior compared to the original three-step sampler in high-dimensional regimes on simulated data as well as data from a variety of applications including gene expression data, infrared spectroscopy data, and socio-economic/law enforcement data. We also provide a detailed theoretical underpinning to the new method by deriving explicit upper bounds for the (geometric) rate of convergence, and by proving that the proposed two-step sampler has superior spectral properties. Supplementary material for this article is available online.     

崎岖地形环境中月球车的动力学建模与仿真

以六轮摇臂-转向架关节式月球车为研究对象,根据其机械原理和结构特点,并参考车辆动力学理论,分析其在崎岖地形中的受力情况,利用Kane方法建立了理想状态下的非线性动力学模型,并基于此模型对月球车进行速度跟踪控制仿真,证实了模型和控制方案的可行性,为设计轨迹跟踪和避障控制器提供依据.     

一种用于音频系统的1.1mW 87dB动态范围的ΔΣ调制器

本文描述了一款应用于音频系统的1.1mW 87dB动态范围的 Delta-Sigma 调制器的设计,设计采用0.18um CMOS工艺。由于采用带有前馈支路的多比特结构,第一级积分器的输出摆幅得到有效压缩。第一级积分器采用结构简单,直流增益仅34dB,工作在1V电压下的电流镜型跨导放大器。在3KHz信号输入下,该调制器可在100Hz~24KHz的频率范围内达到83.8dB的峰值SNDR和87dB的动态范围。