Electrochromic Variation of the Infrared Emissivity in Tungsten Oxide Compounds

The so-called plastic technology first developed for the Li-based batteries leads to a new flexible infrared modulator. Orthorhombic monohydrated tungsten oxide (o-WO³ · H₂O) is used as the active insertion element in the LiCoO₂/o-WO³ · H₂O system. To prevent its degradation under air moisture, the device is protected with hermetic plastic and a window. Measurements of the reflectivity values indicate a very good contrast between the bleached and colored states for the first insertion (about 50% contrast in the 2.5–15 μm range), but the contrast between the inserted and de-inserted states is only about 30%. Optical properties follow quite well Drude mechanism.     

Evaluation of mathematical models for flexible job-shop scheduling problems

With the rapid development in computer technologies, mathematical programming-based technique to solve scheduling problems is significantly receiving attention from researchers. Although, it is not efficient solution method due to the NP-hard structure of these problems, mathematical programming formulation is the first step to develop an effective heuristic. Numerous comparative studies for variety scheduling problems have appeared over the years. But in our search in literature there is not an entirely review for mathematical formulations of flexible job shop scheduling problems (FJSP). In this paper, four the most widely used formulations of the FJSP are compiled from literature and a time-indexed model for FJSP is proposed. These formulations are evaluated under three categories that are distinguished by the type of binary variable that they rely on for using of sequencing operations on machines. All five formulations compared and results are presented.     

Flexible integration of optical switch with optical power splitting and attenuating functions for optical fiber-based networking applications

A flexible integration of optical switch with optical power splitting and attenuating functions has been proposed to optimally serve optical fiber-based networking applications. In this switch, an etched binary-slope sidewall reflector is electrostatically actuated in and out of the plane to manipulate optical signals between input and output optical fibers. The fabrication process is a simple combination of a bulk-silicon micromachining process and silicon-to-glass anodic bonding where fiber alignment grooves, reflectors and actuators are fabricated on the same silicon substrate. Ball-lensed fibers are assembled with the device to achieve high coupling efficiency. Performances of the fabricated devices are measured and discussed. The switching time is less than 9 ms at 31 V. The excess loss of the device is less than 3 dB and the controllable attenuation range is up to 38 dB at 139 V, respectively. Moreover, polarization-dependent loss is less than 0.7 dB in the whole attenuation and splitting range.     

Highly Reproducible Flexible Ion-selective Electrodes for the Detection of Sodium and Potassium in Artificial Sweat

It is well known that potentiometric sensors provide a versatile, cost-effective, and efficient platform for wearable applications. Unfortunately, mass production and commercialization of such devices is often constrained by the requirement of a calibration step, which is due to the poor sensor-to-sensor reproducibility and the need of conditioning the electrodes in the analyte before use. Herein, we fabricated calibration-free flexible sensors including ion-selective electrode and reference electrode by integrating single-walled carbon nanotubes (SWCNTs) with poly(3-octylthiophene) (POT) and applying on polyethylene terephthalate (PET) substrate. The developed sodium and potassium ion-selective electrodes (ISEs) display excellent repeatability, selectivity, stability as well as high sensor-to-sensor reproducibility, with a standard deviation of as low as 1.0 mV in artificial sweat microliter samples volume.     

High Performance Dynamic X-ray Flexible Imaging Realized Using a Copper Iodide Cluster-Based MOF Microcrystal Scintillator

X-ray imaging technology has achieved important applications in many fields and has attracted extensive attentions. Dynamic X-ray flexible imaging for the real-time observation of the internal structure of complex materials is the most challenging type of X-ray imaging technology, which requires high-performance X-ray scintillators with high X-ray excited luminescence (XEL) efficiency as well as excellent processibility and stability. Here, a macrocyclic bridging ligand with aggregation-induced emission (AIE) feature was introduced for constructing a copper iodide cluster-based metal–organic framework (MOF) scintillator. This strategy endows the scintillator with high XEL efficiency and excellent chemical stability. Moreover, a regular rod-like microcrystal was prepared through the addition of polyvinyl pyrrolidone during the in situ synthesis process, which further enhanced the XEL and processibility of the scintillator. The microcrystal was used for the preparation of a scintillator screen with excellent flexibility and stability, which can be used for high-performance X-ray imaging in extremely humid environments. Furthermore, dynamic X-ray flexible imaging was realized for the first time. The internal structure of flexible objects was observed in real time with an ultrahigh resolution of 20 LP mm⁻¹.     

Flexible Rolled Thick‐Film Miniaturized Flow‐Cell for Minimally Invasive Amperometric Sensing

We describe here a miniaturized flexible thick‐film electrochemical biosensor flow detector, suitable for insertion into the lacrimal canaliculus towards minimally invasive amperometric monitoring of biomarkers in the tear fluid. Our focus here is on the microfabrication and in‐vitro testing of the new laterally rolled screen‐printed sensor. The new device responds rapidly and sensitively to dynamic changes in the levels of norepinephrine and glucose (the later in connection to glucose‐oxidase containing ink). Coverage of the enzyme electrode with an electropolymerized polytyramine minimizes contributions from the common electroactive interferences ascorbic and uric acids. Such attractive performance indicates great promise for minimally invasive monitoring of health biomarkers in the tear fluid, or in alternative usage such as capillary microelectrophoresis, ultralow volume sampling, or in‐flow (tubular) systems for batch processing of blood or culture media.     

Dynamically Resettable Electrode-Electrolyte Interface through Supramolecular Sol-Gel Transition Electrolyte for Flexible Zinc Batteries

Flexible batteries based on gel electrolytes with high safety are promising power solutions for wearable electronics but suffer from vulnerable electrode-electrolyte interfaces especially upon complex deformations, leading to irreversible capacity loss or even battery collapse. Here, a supramolecular sol-gel transition electrolyte (SGTE) that can dynamically accommodate deformations and repair electrode-electrolyte interfaces through its controllable rewetting at low temperatures is designed. Mediated by the micellization of polypropylene oxide blocks in Pluronic and host-guest interactions between α-cyclodextrin (α-CD) and polyethylene oxide blocks, the high ionic conductivity and compatibility with various salts of SGTE afford resettable electrode-electrolyte interfaces and thus constructions of a series of highly durable, flexible aqueous zinc batteries. The design of this novel gel electrolyte provides new insights for the development of flexible batteries.     

Printing graphene-carbon nanotube-ionic liquid gel on graphene paper: Towards flexible electrodes with efficient loading of PtAu alloy nanoparticles for electrochemical sensing of blood glucose

The increasing demands for portable, wearable, and implantable sensing devices have stimulated growing interest in innovative electrode materials. In this work, we have demonstrated that printing a conductive ink formulated by blending three-dimensional (3D) porous graphene–carbon nanotube (CNT) assembly with ionic liquid (IL) on two-dimensional (2D) graphene paper (GP), leads to a freestanding GP supported graphene–CNT–IL nanocomposite (graphene–CNT–IL/GP). The incorporation of highly conductive CNTs into graphene assembly effectively increases its surface area and improves its electrical and mechanical properties. The graphene–CNT–IL/GP, as freestanding and flexible substrates, allows for efficient loading of PtAu alloy nanoparticles by means of ultrasonic-electrochemical deposition. Owing to the synergistic effect of PtAu alloy nanoparticles, 3D porous graphene–CNT scaffold, IL binder and 2D flexible GP substrate, the resultant lightweight nanohybrid paper electrode exhibits excellent sensing performances in nonenzymatic electrochemical detection of glucose in terms of sensitivity, selectivity, reproducibility and mechanical properties.     

Micro Electrical Impedance Spectroscopy (μEIS) Fabricated on the Curved Surface of a Fine Needle for Biotissue Discrimination

This work presents a novel micro electrical impedance spectroscopy (μEIS) technique that can measure and discriminate the electrical signal responses of biotissues in real time. An EoN (EIS‐on‐a‐needle), EIS on the surface of a fine needle (400 μm in diameter), was fabricated using a newly developed flexible photomask film. The base material of the photomask is parylene‐C, which allows uniform contact on the curved surface of the needle; thus, the designed electrode patterns of the photomask can be transferred onto the needle surface with a high resolution (2.95 % or less in dimensional error). To validate the developed EoN as an electrical sensor, ex vivo experiments with various biotissues—butchered pork (skin, fat, and muscle) and human breast tissues (normal and cancerous)—were conducted by measuring real‐time electrical impedance during a frequency sweep. The conductivities (relative permittivity) of the pork tissues were evaluated by electrical equivalent circuit analysis: 56.6 mS/m (37,800), 68.0 mS/m (74,755), and 74.9 mS/m (26,145) for the skin, fat, and muscle, respectively. Moreover, the normal and cancerous tissues were well distinguished by electrical resistance at 4.04 kHz for various cancer grades (Elston grades 1, 2, and 3). Analysis of the electrical impedance suggests that the EoN can be utilized to diagnose the physiological states of biotissues in clinical use.     

空间相机中变形镜的结构设计

设计了一种适用于空间环境的变形镜装置,以校正高分辨率空间相机中大口径主反射镜的波像差.讨论了空间相机用变形镜的设计准则,确定了该变形镜的结构形式;给出了具体的结构组成和材料组合,并设计了柔性结构.仿真结果表明,该结构在z向重力工况下RMS值仅17.2nm,4℃温升时的RMS值仅为3.7nm,且一阶频率为1 015Hz,各模拟空间工况下的反射面经主动展平后,均可获得近似的标准平面;该结构能够较准确地拟合前36项泽尼克多项式所对应的基元波面,残留误差较小,不仅具有良好的力学性能和热稳定性,还能保证变形镜的像差校正能力得到充分发挥,从而满足空间相机的使用需求.