Design and Analysis of a Permanent Magnet Spherical Actuator

This paper has proposed a 3-DOF spherical actuator consisting of a ball-shaped rotor with a full circle of permanent- magnet (PM) poles and a spherical-shell-like stator with two layers of circumferential air-core coils. One key feature of this design is the parametrization of PM and coil poles. Based on the torque model of the PM spherical actuator, the relationship between poles' parameters and torque output can be demonstrated. As a result, the actuator design aiming at achieving maximum torque output can be carried out from the relationships. Another advantage of this spherical actuator is its singularity-free workspace, which is verified with the actuator torque model and condition numbers.     

Simulation of Active-Matrix Electrophoretic Display Response Time Optimization by Dual-Gate a-Si:H TFT With a Common Gate Structure

Large off-state drain-source current of the thin-film transistor (TFT) in active-matrix electrophoretic display (AMEPD) pixel leads to dramatic data voltage degradation, which causes severe crosstalk and undesired large response time. In this paper, the leakage current influence on response time is investigated and simulated. A compact model of response time t versus off-state drain-source current I _off is established. The simulation result induces that by reducing I _off the response time can be efficiently shorted. In order to reduce the off-state current, dual-gate amorphous silicon (a-Si:H) TFT with a common gate structure is discussed. Its current regulation mechanism is illustrated, and its fitness for driving the AMEPD pixel is explained. The SPICE simulation results prove that except reducing the crosstalk, dual-gate a-Si TFT can also significantly short the response time by cutting down the off-state current under the operation conditions of AMEPD application, while insignificantly reduces the on-state current.     

基于荧光光谱法的皮肤胆固醇快速无创检测技术

皮肤胆固醇含量可以作为评价动脉粥样硬化的重要指标之一,现有的皮肤胆固醇含量检测主要基于实验室活检进行,缺少快速无创的检测技术和装备。针对以皮肤胆固醇含量为评价指标的动脉粥样硬化的早期快速筛查需求,本文提出了基于荧光光谱法的皮肤胆固醇快速无创检测方法,研发了一种皮肤胆固醇无创检测系统。为了提高测量的准确性和稳定性,该系统对温度引起的检测试剂荧光效率的波动进行了修正。本文结合气相色谱法对测量结果的准确性进行了验证,并通过检测正常人群和动脉粥样硬化高风险人群的皮肤胆固醇含量,明确了该系统的临床应用价值。本文的研究结果表明,462~520 nm波段内的平均荧光强度与温度的相关系数为-0.995(p<0.0001),可据此建立温度校准曲线对由温度差异引起的荧光波动进行修正。校正后,系统测量的皮肤胆固醇含量与气相色谱测量值的相关性显著,相关系数为0.905(p<0.0001)。在动脉粥样硬化高风险人群的筛查实验中,动脉粥样硬化高风险人群和正常人群的皮肤胆固醇检测结果具有显著差异(P=0.0004)。与现有技术相比,基于荧光光谱法的皮肤胆固醇检测技术具有测量快速无创等优势,为大规模开展动脉粥样硬化的早期风险筛查提供了先进技术手段。     

基于磁耦合共振传输技术的手机无线充电系统设计与研究

在社会经济与科技飞速进步的背景下,手机已经成为人们日常生活、工作中不可或缺的重要工具.无线充电系统能够较好地提升电能转化的效率,实现更加高效便捷的充电模式,应用磁耦合技术较好的摆脱充电线和充电接口的限制影响.文章系统性地介绍了磁耦合共振的工作原理和基本模型,结合手机无线充电的优势和现状,详细分析了该技术在充电系统中的设...     

Design and optimization of an integrated MEMS gas chamber with high transmissivity

Non-Dispersive InfraRed (NDIR) gas sensor is widely used for gas detection in collieries and the gas chemical industry, etc. The performance of the NDIR gas sensor depends on the volume, optical length and transmittance of the gas chamber. However, the existing gas sensor products have problems of large volume, high cost and incapable of integration, which need to develop towards the miniaturized sensor. This paper first presents the theoretical background of the NDIR gas sensor and the novel structure of a fully integrated infrared gas sensor and its micro-machined gas chamber structure. Then, the light structure and the gas flow of the gas chamber are optimized on Tracepro software and Ansys workbench, respectively, and the technological process for preparing the Micro-Electro-Mechanical System (MEMS) gas chamber is designed. Finally, we produce a gas chamber with a small volume and good transmissivity, which would be the most important part of producing the miniaturized NDIR gas sensor.     

Synthesizing Multi-Contrast MR Images Via Novel 3D Conditional Variational Auto-Encoding GAN

Mobile Networks and Applications - As two different modalities of medical images, Magnetic Resonance (MR) and Computer Tomography (CT), provide mutually-complementary information to doctors in...     

组织光透明技术在骨透明化中的生物医学成像应用与展望

近年来组织光透明技术的飞速发展,为现代骨科临床基础研究带来了新的契机.组织光透明技术主要通过多种物理、化学手段,降低组织的光散射和光吸收,使光能在组织中更好地传播,从而增加光学成像的深度和对比度.结合多种荧光标记策略,实现更深层、更高分辨的骨组织及三维空间微结构信息,为突破骨这种高散射组织及骨疾病的分子影像学研究带来新...     

基于太赫兹辐射的甘草主成分光谱分析

采用透射式太赫兹时域光谱系统测试了甘草主成分甘草酸、甘草次酸以及甘草苷的太赫兹光谱,发现甘草酸、甘草次酸以及甘草苷在0.3～1.72 THz频段内具有明显的吸收特征,此频段内它们的太赫兹吸收峰峰位接近、吸收谱谱线相似.利用量子化学方法模拟甘草酸的太赫兹吸收谱,并与实验谱进行对比指认完成对3种单质的定性分析工作.本文分别...     

Mimic Drug Dosage Modulation for Neuroplasticity Based on Charge-Trap Layered Electronics

The human brain is often likened to an incredibly complex and intricate computer, rather than electrical devices, consisting of billions of neuronal cells connected by synapses. Different brain circuits are responsible for coordinating and performing specific functions. The reward pathway of the synaptic plasticity in the brain is strongly related to the features of both drug addiction and relief. In the current study, a synaptic device based on layered hafnium disulfide (HfS₂) is developed for the first time, to emulate the behavioral mechanisms of drug dosage modulation for neuroplasticity. A strong gate-dependent persistent photocurrent is observed, arising from the modulation of substrate-trapping events. By controlling the polarity of gate voltage, the basic functions of biological synapses are realized under a range of light spiking conditions. Furthermore, under the control of detrapping/trapping events at the HfS₂/SiO₂ interface, positive/negative correlations of the A_n/A₁ index, which significantly reflected the weight change of synaptic plasticity, are realized under the same stimulation conditions for the emulation of the drug-related addition/relief behaviors in the brain. The findings provide a new advance for mimicking human brain plasticity.     

Modification of Energy Level Alignment for Boosting Carbon-Based CsPbI2Br Solar Cells with 14% Certified Efficiency

Hole transfer material (HTM)-free, carbon-based all-inorganic perovskite solar cells (C-PSCs) are promising alternatives to conventional organic–inorganic hybrid PSCs in addressing thermal and moisture instability issues. However, the energy level mismatch between the inorganic perovskite and carbon electrode coupled, together with the incapability of the carbon electrode to reflect incident light for reabsorption, limits the power conversion efficiency (PCE) of C-PSCs. To address these issues, herein, a new strategy of a hexyltrimethylammonium bromide (HTAB)-modified CsPbI₂Br perovskite surface is devised to reduce this energy offset from 0.70 to 0.32 eV and increase the built-in potential by 70 mV for the final devices. Additionally, a CsPbI₂Br perovskite film with a thickness of up to 800 nm is realized via a hot-flow-assisted spin coating approach in an ambient atmosphere with humidity of less than 80%. Reduced energy offset coupled with suppressed charge recombination and thick perovskite layer boosts the champion PCE of CsPbI₂Br C-PSCs to 14.3% (J_sc = 14.1 mA cm⁻², V_oc = 1.26 V, and fill factor = 0.806), and the average PCE to 13.9% under one sun illumination. A new certified efficiency record of 14.0% is obtained for HTM-free inorganic C-PSCs. Meanwhile, the moisture-resistant barrier from the alkyl chain in HTAB improves the stability of the final devices.