棱镜波导结构的古斯-汉欣位移模拟

模拟并分析了波长为633 nm的偏振光通过Kretschmann-Raether微米级棱镜波导结构时的古斯-汉欣位移.在金膜厚度为45 nm的条件下,当入射角为44.1°时,利用稳态相位理论,得到的最大束位移为+120μm;当入射角为44.1°时,利用COMSOL Multiphysics5.1软件中的波动光学模块,得到的最大束位移为+3.37 μm.在共振角附近,COMSOL Multiphysics5.1模拟软件与稳态相位理论均得到正的古斯-汉欣位移,但是COMSOL Multiphysics5.1软件模拟的结果远小于稳态相位理论仿真的结果.该研究对设计基于古斯-汉欣位移测量的高灵敏度传感器具有指导意义.     

Photovoltaic performance of Gallium-doped ZnO thin film/Si nanowires heterojunction diodes

In this work, photovoltaic performance of Ga-doped ZnO thin film/Si NWs heterojunction diodes was investigated. Highly dense and vertically well-aligned Si NW arrays were successfully synthesised on a p-type (1?0?0)-oriented Si wafer through cost-effective metal-assisted chemical etching technique. Ga-doped ZnO thin films were deposited onto Si NWs via radio frequency magnetron sputtering to construct three-dimensional heterostructures. Photovoltaic characteristics of the fabricated diodes were determined with current density (J)–voltage (V) measurements under simulated solar irradiation of AM 1.5 G. The optimal open-circuit voltage, short-circuit current density, fill factor and power conversion efficiency were found to be 0.37 V, 3.30 mA cm^?2, 39.00 and 0.62%, respectively. Moreover, photovoltaic diodes exhibited relatively high external quantum efficiency over the broadband wavelengths between 350 and 1100 nm interval of the spectrum. The observed photovoltaic performance in this study clearly indicates that the investigated device structure composed of Ga-doped ZnO thin film/Si NWs heterojunctions could facilitate an alternative pathway for optoelectronic applications in future, and be a promising alternative candidate for high-performance low-cost new-generation photovoltaic diodes.     

Flexible Aqueous Lithium‐Ion Battery with High Safety and Large Volumetric Energy Density

A flexible and wearable aqueous lithium‐ion battery is introduced based on spinel Li_1.1Mn₂O₄ cathode and a carbon‐coated NASICON‐type LiTi₂(PO₄)₃ anode (NASICON=sodium‐ion super ionic conductor). Energy densities of 63 Wh kg^?1 or 124 mWh cm^?3 and power densities of 3 275 W kg^?1 or 11.1 W cm^?3 can be obtained, which are seven times larger than the largest reported till now. The full cell can keep its capacity without significant loss under different bending states, which shows excellent flexibility. Furthermore, two such flexible cells in series with an operation voltage of 4 V can be compatible with current nonaqueous Li‐ion batteries. Therefore, such a flexible cell can potentially be put into practical applications for wearable electronics. In addition, a self‐chargeable unit is realized by integrating a single flexible aqueous Li‐ion battery with a commercial flexible solar cell, which may facilitate the long‐time outdoor operation of flexible and wearable electronic devices.     

Electrochemical Red Blood Cell Counting: One at a Time

We demonstrate that the concentration of a red blood cell solution under physiological conditions can be determined by electrochemical voltammetry. The magnitude of the oxygen reduction currents produced at an edge‐plane pyrolytic graphite electrode was diagnosed analytically at concentrations suitable for a point‐of‐care test device. The currents could be further enhanced when the solution of red blood cells was exposed to hydrogen peroxide. We show that the enhanced signal can be used to detect red blood cells at a single entity level. The method presented relies on the catalytic activity of red blood cells towards hydrogen peroxide and on surface‐induced haemolysis. Each single cell activity is expressed as current spikes decaying within a few seconds back to the background current. The frequency of such current spikes is proportional to the concentration of cells in solution.     

物联网嵌入式智能设备实时控制系统设计

随着智能设备功能业务的逐渐扩展,用户对智能设备控制系统的实时性要求越来越高,当前控制系统采用CAN技术实现智能设备与用户间的通信,无法满足用户对系统实时性的需求。提出一种新的物联网嵌入式智能设备实时控制系统,通过构建系统的总体框架,将嵌入式LPC2378 ARM处理器作为核心处理器,通过RS-485总线将智能设备连接在一起,和处理器构成一个总线传输网络,在嵌入式LPC2378 ARM处理器中,将带DMA的10/100M以太网模块和以太网PHY芯片DP83848I连接,以提高数据包的传输效率,增强系统的实时性。系统GPRS模块选择SIM300CZ模块,将远程报警模块和RS-485总线结合在一起,共同实现远程报警和控制功能。软件设计时,给出了软件的整体架构和总体流程图,介绍了部分存储代码。实验结果表明,所设计系统对智能设备有很高的控制性能。     

一种双轴姿态稳定平台的设计与实现

机载姿态稳定平台可隔离载体角运动、精确跟踪当地水平面,因此在航空遥感领域中有着广泛的应用前景。通过以微惯性传感器作为主要测量元件,以步进电机作为执行机构,构建了一种双轴姿态稳定平台,进行姿态的闭环控制,克服了传统陀螺稳定平台造价昂贵、设计复杂的特点。试验测试结果表明,该平台可以实现对当地水平面的精确跟踪。     

Coupling of the Decarboxylation of 2‐Cyano‐2‐phenylpropanoic Acid to Large‐Amplitude Motions: A Convenient Fuel for an Acid–Base‐Operated Molecular Switch

The decarboxylation of 2‐cyano‐2‐phenylpropanoic acid is fast and quantitative when carried out in the presence of 1 molar equivalent of a [2]catenane composed of two identical macrocycles incorporating a 1,10‐phenanthroline unit in their backbone. When decarboxylation is over, all of the catenane molecules have experienced large‐amplitude motions from neutral to protonated catenane, and back again to the neutral form, so that they are ready to perform another cycle. This study provides the first example of the cyclic operation of a molecular switch at the sole expenses of the energy supplied by the substrate undergoing chemical transformation, without recourse to additional stimuli.     

A Highly Stable Nonhysteretic {Cu2(tebpz) MOF+water} Molecular Spring

A molecular spring formed by a hydrophobic metal–organic framework Cu₂(tebpz) (tebpz=3,3′,5,5′‐tetraethyl‐4,4′‐bipyrazolate) and water is presented. This nanoporous heterogeneous lyophobic system (HLS) has exceptional properties compared to numerous reported systems of such type in terms of stability, efficiency, and operating pressure. Mechanical and thermal energetic characteristics as well as stability of the system are discussed and compared in detail with those of other previously reported HLS.     

Rapid screening,separation, and detection of hydroxyl radical scavengers from total flavonoids of Ginkgo biloba leaves by chromatography combined with molecular devices

Hydroxyl radicals are the most reactive free radical of human body, a strong contributor to tissue damage. In this study, liquid chromatography coupled to electrospray ionization mass spectrometry was applied to screen and identify hydroxyl radical scavengers from the total flavonoids of Ginkgo biloba leaves, and high‐performance counter current chromatography was used to separate and isolate the active compounds. Furthermore, molecular devices were used to determine hydroxyl radical scavenging activities of the obtained hydroxyl radical scavengers and other flavonoids from G. biloba leaves. As a result, six compounds were screened as hydroxyl radical scavengers, but only three flavonoids, namely, rutin, cosmos glycosides and apigenin‐7‐O‐Glu‐4’‐O‐Rha, were isolated successfully from total flavonoids by high‐performance counter current chromatography. The purities of the three obtained compounds were over 90%, respectively, as determined by liquid chromatography. Molecular devices with 96‐well microplates evaluation indicated that the 50% scavenging concentration values of screened compounds were lower than that of other flavonoids, they performed greater hydroxyl radical scavenging activity, and the evaluation effects were consistent with the liquid chromatography with mass spectrometry screening results. Therefore, chromatography combined with molecular devices is a feasible and an efficient method for systematic screening, identification, isolation, and evaluation of bioactive components in mixture of botanical medicines.     

Ruthenium‐Amine Conjugated Organometallic Materials for Multistate Near‐IR Electrochromism and Information Storage

Monometallic and dimetallic complexes with the ruthenium‐amine conjugated structural unit have been prepared. These complexes display consecutive redox waves with low potentials and rich and intense absorptions in the near‐infrared region. The electrochemical and spectroscopic properties can be modulated using substituents or auxiliary ligands with different electronic natures. Through simple functionalization, electropolymerized or monolayer thin films of these complexes have been prepared. These films display multistate near‐infrared electrochromism with good contrast ratios and long optical retention times. In addition, flip‐flop and flip‐flap‐flop memories have been demonstrated on the basis of these thin films.