A Jitter Injection Signal Generation and Extraction System for Embedded Test of High-Speed Data I/O

An instrument for on-chip measurement of transceiver transmission capability is described that is fully realizable in CMOS technology and embeddable within an SoC. The instrument can be used to inject and extract the timing and voltage information associated with signals in high-speed transceiver circuits that are commonly found in data communication applications. At the core of this work is the use of ΣΔ amplitude- and phase-encoding techniques to generate both the voltage and timing (phase) references, or strobes used for high-speed sampling. The same technique is also used for generating the test stimulant for the device-under-test.     

A 16 MHz, 59.2 ppm/°C CMOS DLL-Assisted VCO with Improved Frequency Stability Towards Single Chip Wireless IOT

A 16 MHz, highly stable voltage controlled oscillator (VCO) is reported in this paper. The proposed VCO consists of three cross-coupled RC stages, and is fully compatible with standard CMOS process. A positively biased PN junction with negative temperature coefficient is incorporated in the design to compensate frequency drift. In addition, a delay locked loop (DLL) directly following the VCO is utilized to further improve the output stability caused by temperature variations. The designed circuit was implemented using CMOS 0.18 μm technology, and was validated through experiments. Measurement results show that the DLL-assisted VCO output variation across the 25~120 °C temperature range is less than 0.56 %, corresponding to 59.2 ppm/°C. It also shows that the output standard deviation of the DLL-assisted VCO is only 6.816 KHz, ~ 16.6 % better compared with the same VCO without DLL’s assistance.     

Modulation of Carbon Nanotubes' Perturbation to the Metabolic Activity of CYP3A4 in the Liver

The liver plays an important role in metabolizing foreign materials, such as drugs. The high accumulation of carbon nanotubes and other hydrophobic nanoparticles in the liver has raised concerns that nanoparticles may interfere with liver metabolic function. We report here that carbon nanotubes enter hepatic cells after intravenous introduction and interact with CYP enzymes, including CYP3A4. Surface chemical modifications alter the carbon nanotubes' interactions with CYP450 enzymes in human liver microsomes. They enhance, inhibit, or have no effect on the enzymatic function of CYP3A4. Using a cheminformatics analysis, certain chemical structures are identified on the surface of the carbon nanotubes that induce an enzyme inhibitory effect or prevent disruption of CYP3A4 enzymes.     

Magnetically Driven Silver‐Coated Nanocoils for Efficient Bacterial Contact Killing

The increasing threat of multidrug‐resistant bacterial strains against conventional antibiotic therapies represents a significant worldwide health risk and intensifies the need for novel antibacterial treatments. In this work, an effective strategy to target and kill bacteria using silver‐coated magnetic nanocoils is reported. The coil palladium (Pd) nanostructures are obtained by electrodeposition and selective dealloying, and subsequently coated with nickel (Ni) and silver (Ag) for magnetic manipulation and antibacterial properties, respectively. The efficiency of the nanocoils is tested in the treatment of Gram‐negative Escherichia coli (E. coli) and Gram‐positive methicillin‐resistant Staphylococcus aureus (S. aureus), both of which represent the leading multidrug‐resistant bacterial pathogens. The nanocoils show highly effective bacterial killing activity at low concentrations and in relatively short durations of treatment time. Three different investigation techniques, LIVE/DEAD assay, colony‐forming unit counting, and scanning electron microscope, reveal that the antibacterial activity is a result of bacterial membrane damage caused by direct contact with the nanocoil. The low cytotoxicity toward fibroblast cells along with the capability of precise magnetic locomotion makes the proposed nanocoil an ideal candidate to combat multidrug‐resistant bacteria in the field of biomedical and environmental applications.     

Synthesis of Millimeter‐Scale Transition Metal Dichalcogenides Single Crystals

The emergence of semiconducting transition metal dichalcogenide (TMD) atomic layers has opened up unprecedented opportunities in atomically thin electronics. Yet the scalable growth of TMD layers with large grain sizes and uniformity has remained very challenging. Here is reported a simple, scalable chemical vapor deposition approach for the growth of MoSe₂ layers is reported, in which the nucleation density can be reduced from 10⁵ to 25 nuclei cm^?2, leading to millimeter‐scale MoSe₂ single crystals as well as continuous macrocrystalline films with millimeter size grains. The selective growth of monolayers and multilayered MoSe₂ films with well‐defined stacking orientation can also be controlled via tuning the growth temperature. In addition, periodic defects, such as nanoscale triangular holes, can be engineered into these layers by controlling the growth conditions. The low density of grain boundaries in the films results in high average mobilities, around ≈42 cm² V^?1 s^?1, for back‐gated MoSe₂ transistors. This generic synthesis approach is also demonstrated for other TMD layers such as millimeter‐scale WSe₂ single crystals.     

基于能量传输模型的QCM负载效应研究

为准确、有效地区分引起石英晶体微天平(QCM)频偏的质量效应与阻尼效应,运用能量传输模型(ETM)的基本原理,推导出液体粘度和密度的乘积与石英晶体谐振器表面最大的振动幅度之间的显性函数关系式。可通过测试QCM的谐振频率与幅值信息将其负载效应分开,为QCM免疫传感器在医学中的诊断提供了一种理论基础。     

基于二维压缩感知和分层特征的图像检索算法

为了保留图像分析时的像素点位置关系及降维处理,把一维压缩感知理论推广到二维,建立了二维可稀疏信号的压缩测量模型,研究了一种二维信号的自适应梯度下降重构AGDR(Adaptive Gradient Descent Recursion)算法,由此提出了一种图像分层特征提取与检索方法.首先对图像在RGB颜色空间上进行网格离散划分,通过分层算子对图像进行分层映射,定义一种基于颜色网格空间的扩展灰度共生矩阵,采用二维测量模型获取图像的分层测量特征、纹理特征与分层颜色统计特征,图像分层测量特征综合反映出图像的颜色及像素点位置的关系,扩展灰度共生矩阵反映纹理特征.其次用AGDR算法计算检索图像之间的原始信号差量及其稀疏值.最后结合两类分层特征差量、稀疏值和颜色统计特征,融合计算图像间整体相似度度量指标.仿真实验表明,应用分层二维压缩感知测量与AGDR算法的图像检索方法在检索时间、查全率和查准率等指标上具有优越性能,为图像检索提供了新思路.     

LiNbO_3:Fe和LiNbO_3:Fe:Mn晶体非挥发全息存储的理论研究

以双中心模型为基础,理论研究了连续光条件下近化学比LiNbO3:Fe和LiNbO3:Fe:Mn晶体在稳态情况下的非挥发双色二步全息存储性能.通过考虑在深、浅能级中心之间所有可能的电子交换过程,从理论上证实了在低光强范围内LiNbO3:Fe晶体比LiNbO3:Fe:Mn晶体有着更大的空间电荷场、更高的记录灵敏度和动态范围.     

低应力PECVD SiC晶圆级薄膜封装新技术

为了解决MEMS封装过程中易对微致动件造成损伤的问题,提出了一种低成本、与CMOS工艺兼容的晶圆级薄膜封装技术,用等离子体增强化学气相淀积(PECVD)法制备的低应力SiC作为封装和密封材料。此材料的杨氏模量为460 GPa,残余应力为65 MPa,可使MEMS器件悬浮时封装部位不变形。与GaAs,Si半导体材料相比,SiC具有较佳的物理稳定性,较高的杨氏模量等性能优势。将PECVD薄膜封装技术用于表面微结构和绝缘膜上Si(SOI)微结构部件(如射频开关、微加速度计等)封装中,不仅减小了封装尺寸,降低了芯片厚度,简化了封装工艺,而且封装芯片还与CMOS工艺兼容。较之晶圆键合封装方式,此晶圆级薄膜封装成本可降低5%左右。