销钉耳片连接件接触应力分析的能量解法

针对光滑无间隙的钉孔接触情况,根据圣维南原理,以耳片孔为中心取出一圆形区域,采用叠加原理将受力状态分解为对称和反对称状态,利用正交完备的三角级数和勒让德级数构造这两种受力状态的位移场.假设接触表面的载荷分布模态,由最小势能原理确定位移函数中的待定系数,得到耳片孔边的位移场和应力场.本文计算结果与有限元数值解比较显示:两...     

A multi-channel sensor based on 8-hydroxyquinoline ferrocenoate for probing Hg(II) ion

A new sensing molecule 8-hydroxyquinoline ferrocenoate (Fc-Q) which combines ferrocene and 8-hydroxyquinoline moieties was synthesized and applied as a multi-channel sensor for the detection of Hg²⁺ ion. Fc-Q can coordinate with Hg²⁺ to give colorimetric, fluorescent and electrochemical responses. Upon complexation with Hg²⁺ ion, the characteristic absorption peak is red-shifted (Δλ = 45 nm), the fluorescent intensity is quenched at 303 nm, and the oxidation peak is cathodic shifted (ΔE_1/2 = −149 mV). Quantitatively analyzed Hg²⁺ ions at the range of ppb level could be achieved by electrochemical response. For the practical application of sensing Hg²⁺ in real world water, Fc-Q modified screen-printed carbon electrodes were obtained for facile, sensitive, and on-site analysis of Hg²⁺.     

Impact of elliptical cross-section on the propagation delay of multi-channel gate-all-around MOSFET based inverters

Multi-channel (MC) gate-all-around (GAA) metal-oxide-semiconductor field-effect transistor (MOSFET) is one of the promising candidates for the next-generation high performance devices. However, due to fabrication imperfections the cross-section of GAA devices may be ellipse-shaped having different major (a) and minor (b) axes, instead of the theoretically ideal round shape. The aspect ratio (AR), defined as a/b, of such elliptical GAA devices can vary depending on a and b. This introduces variability in the effective diameter, which in turn affect the performance parameters of circuits based on elliptical GAA MOSFETs. In the present work we have investigated the impact of diameter variability on the transient response of MC elliptical GAA MOSFET based CMOS inverters with a novel perspective. We have modeled the spread in the effective diameter by a parameter, σ, the standard deviation (SD), which may be thought of as a quantitative measure of the amount of variability introduced in the device. We have elaborated the ‘ON-Resistance’ method for calculating the propagation delay of MC GAA MOSFET based CMOS inverters. Computations were carried out to show the dependence of the propagation delay of such inverters on some important device/circuit parameters. We have also shown that even long channel elliptical devices can offer significant reduction of circuit delay (comparable to short channel devices) by proper tuning the effective diameter and number of channels, provided the admissible small dimensional effects have been taken into account.     

基于CPCI总线多通道并行A/D采集卡设计

提出了一种基于CPCI总线多通道并行A/D采集卡的设计方案。该板卡应用高精度∑-ΔA/D转换器,研究解决了频率特性不同的多通道电压量实时采集,完成了CPCI总线多通道并行A/D采集卡设计。该板卡既可以实现并行采集,实时性强;又能适用于多种频率被测电压量的情况,适用范围更广。     

用于运动目标探测的多通道成象系统

本文提出了一种采用自聚焦(GRIN)透镜阵列对运动目标进行探测的多通道光学成象系统.与单孔径成象系统比较,多通道成象系统具有更宽的视场和更高的运动敏感度,使之更适合于对运动目标的捕获、跟踪以及对运动量的测定.本文根据复眼的视觉机制和自聚焦透镜的成象原理,对运动目标进行了成象与测定实验.此外,初步介绍了为提高图象分辨率而采用的并行多通道处理技术.     

Chaos in complex motor networks induced by Newmanben Watts small-world connections

We investigate how dynamical behaviours of complex motor networks depend on the Newman-Watts small-world (NWSW) connections. Network elements are described by the permanent magnet synchronous motor (PMSM) with the values of parameters at which each individual PMSM is stable. It is found that with the increase of connection probability p, the motor in networks becomes periodic and falls into chaotic motion as p further increases. These phenomena imply that NWSW connections can induce and enhance chaos in motor networks. The possible mechanism behind the action of NWSW connections is addressed based on stability theory.     

无线网络中iSCSI性能的研究

在介绍和分析标准iSCSI协议体系结构的基础上,给出了在iSCSI会话中通过建立多个虚拟TCP连接且在无线局域网中的iSCSI层采用并行工作机制的优化方法,并对其性能进行了理论分析和实验测试.结果表明,与标准iSCSI相比,在无线网络中使用多连接TCP能有效的改善iSCSI协议的存储性能.     

A combined multi-channel Wiener filter-based noise reduction and dynamic range compression in hearing aids

Noise reduction (NR) and dynamic range compression (DRC) are basic components in hearing aids, but generally these components are developed and evaluated independently of each other. Hearing aids typically use a serial concatenation of NR and DRC. However, the DRC in such a concatenation negatively affects the performance of the NR stage: the residual noise after NR receives more amplification compared to the speech, resulting in a signal-to-noise-ratio (SNR) degradation. The integration of NR and DRC has not received a lot of attention so far. In this paper, a multi-channel Wiener filter (MWF)-based approach is presented for speech and noise scenarios, where an MWF-based NR algorithm is combined with DRC. The proposed solution is based on modifying the MWF and the DRC to incorporate the conditional speech presence probability in order to avoid residual noise amplification. The goal is then to analyse any undesired interaction effects by means of objective measures. Experimental results indeed confirm that a serial concatenation of NR and DRC degrades the SNR improvement provided by the NR, whereas the combined approach proposed here shows less degradation of the SNR improvement at a low increase in distortion compared to a serial concatenation.     

Simulation of the electrostatic and transport properties of 3D-stacked GAA silicon nanowire FETs

This paper presents a detailed comparative study of the switching characteristics of resistive memory devices, with NiO or HfO₂ active materials and Pt electrodes, based on identical integration schemes. Material screening and qualification are performed using structural and composition analyses. Preliminary electrical investigations outline the non-polar switching behavior of both HfO₂ and NiO devices. Then, by using a specific test setup, we present a systematic comparative study of HfO₂ and NiO devices, clearly showing the tunability of the electrical characteristics with material type and process. HfO₂ devices lead to largest High Resistance State/Low Resistance State ratios and higher forming voltages compared to NiO cells, while reset voltages are similar. Data retention of both materials show highly stable Low Resistance State, while High Resistance State increases over time under 85 °C baking.     

Regulating the slow magnetic relaxation behavior of two different shapes Dy4 clusters with in situ formed penta- and heptadentate Schiff base ligands

The design and synthesis of clusters possessing the same number of cores but different connection methods and properties have always been difficult. Herein, we used 2-pyridinaldehyde, 1,3-diamino-2-propanol, and Dy (ClO₄)₃·6H₂O at room temperature (RT) to obtain the cluster [Dy₄(L¹)₄(μ₂-OH)₄]·4ClO₄⁻ ( 1 , HL¹ = 2-pyridinecarboxaldehyde-1,3-diamino-2-propanol) with square Dy₄O₈ cluster cores. Cluster 1 consisted of four Schiff base ligands (L¹)⁻, four Dy(III) ions, four bridged (μ₂-OH)⁻, and four free ClO₄⁻. The ligand HL¹ was formed by in situ Schiff base reaction with 2-pyridinecarbaldehyde and 1,3-diamino-2-propanol in the presence of Dy(III) ions. 2-Aldehyde-8-hydroxyquinoline, 1,3-diamino-2-propanol, and Dy (NO₃)₃·6H₂O reacted at RT to yield a tetranuclear Dy(III) cluster [Dy₄(L²)₂(μ₃-OH)₂(NO₃)₄(EtOH)₂]·2CH₃CN ( 2 , H₃L² = 2-aldehyde-8-hydroxyquinoline-1,3-diamino-2-propanol) with butterfly-shaped Dy₄O₆ cluster core. Cluster 2 consisted of two ligands (L²)³⁻, four Dy(III) ions, two bridged μ₃-OH, two end-group-coordinated ethanol molecules, and four bidentate-chelated NO₃⁻. The in situ reaction of 2-aldehyde-8-hydroxyquinoline and 1,3-diamino-2-propanol under Dy(III) ion-assisted catalytic conditions provided the ligand H₃L². It is worth noting that the magnetic test showed that 1 is a typical single-molecule magnet (SMM), whereas 2 only showed a significant frequency dependence behavior. We considered Orbach and Raman processes (τ⁻¹ = τ₀⁻¹ exp(−U_eff/k_BT) + CTⁿ) to fit 1 and 2 in the high-temperature range and obtained U_eff = 7.01 and 5.43 K and τ₀ = 1.18 × 10⁻⁴ and 4.14 × 10⁻⁵ s, respectively.