Photonic crystal (PC) can manipulate light propagation due to the presence of photonic band gap (PBG). PBG can redistribute density of optical state. When the PBG overlaps with the emission of an ...emitter embedded in PC, the excited electrons will be prohibited from transferring to the ground state. Introducing PC with suitable PBG into photocatalyst will partially reduce the electron-hole combination and improve photocatalytic efficiency. Meanwhile, appropriate specific surface area of 3-D quasi-ordered structure can increase the contact area of catalysts and CO.sub.2 to provide more catalytic sites, which plays an important role in the improvement of photocatalytic activity. Herein, SiO.sub.2@Ni/TiO.sub.2 PCs with designed PBG were fabricated and applied as catalysts for photocatalytic CO.sub.2 reduction using Ru(bpy).sub.3Cl.sub.2·6H.sub.2O as photosensitizer. The designed SiO.sub.2@Ni/TiO.sub.2 PCs has a suitable specific surface area and certain surface roughness, which can effectively adsorb CO.sub.2 for photocatalytic reduction. Meanwhile, the PBG of SiO.sub.2@Ni/TiO.sub.2 PCs matches well with the electron-hole combination energy of the photosensitizer, the electron-hole combination process from the excited state falling back to the ground state can be prevented partially. Suppressing the falling of excited electrons will make electrons transfer to the catalyst, thereby improving the photocatalytic performance. Graphic
Over the past decade, system-on-chip (SoC) designs have evolved to address the ever increasing complexity of applications, fueled by the era of digital convergence. Improvements in process technology ...have effectively shrunk board-level components so they can be integrated on a single chip. New on-chip communication architectures have been designed to support all inter-component communication in a SoC design. These communication architecture fabrics have a critical impact on the power consumption, performance, cost and design cycle time of modern SoC designs. As application complexity strains the communication backbone of SoC designs, academic and industrial R&D efforts and dollars are increasingly focused on communication architecture design. This book is a comprehensive reference on concepts, research and trends in on-chip communication architecture design. It will provide practitioners, researchers, software developers and students with a comprehensive survey, not available elsewhere, of all current standards for on-chip communication architectures.
Polycarbonate (PC) is susceptible to environmental stress cracking (ESC) when the conditions of pre-strain and presence of fluid with a compatible solubility index are both prevalent. One approach to ...counter this involves using nanoscale fillers to bridge the propagating microcracks, thus, effectively inhibiting impending failure. In this work, we report incorporation of titania (TiOsub.2) with different nanoscale morphologies into polycarbonate matrix to assess its effect on ESC resistance against dioctyl phthalate (DOP). Using a hydrothermal process with a NaOH/Ti molar ratio of 72, TiOsub.2 nanostructures were produced containing nanosheets with large surface area and nanotubes having typical diameter and length values of 15-20 nm and a few hundred nanometers, respectively. PC/TiOsub.2 composites were fabricated with up to 0.5 weight percent of TiOsub.2 nanoparticles (NPs), nanowires (NWs), or hybrid nanostructures (HNs). ESC tests were conducted by exposing test coupons to DOP oil at different temperatures and pre-strain conditions. The results showed that, under identical test conditions, while as-received PC grade exhibited complete fracture in ~3.1 h, PC/TiOsub.2-0.05HN composite took ~70 h to fail via surface cracking. SEM examination of the fracture surface revealed that homogeneous dispersion and efficient load-bearing capability of TiOsub.2 nanotubes and nanosheets impeded localized crack propagation by bridging the gap between the PC matrix segments. Liquid nitrogen fracture of the PC/TiOsub.2 composite further confirmed the critical role of TiOsub.2 hybrid nanostructures towards improvement in ESC resistance of PC matrix composites.
Polycarbonate (PC) composites are often used in the production of high value-added products, but it is necessary to improve its environment stress cracking condition in the presence of pre-strain and ...soluble solvents. In this work, the effect of weight reduction and strengthening is realized by introducing microstructures and hollow glass microspheres (HGMs) into the PC composites. It is found that the addition of HGMs can reduce the melt viscosity and T.sub.g value of the composite materials, which will change the foaming behavior of PC/HGMs composites. Besides, the effect of different content of HGMs and foaming temperature on the foaming behavior of PC/HGMs composite foams are studied. The PC/HGMs composite foams exhibit a typical structure of both large and small cellular pores, because of the existence of hollow beads and cellular structures. Moreover, compared to the neat PC foam, the tensile strength as well as the flexural strength of the composite foams are significantly increased by 110.9% and 364.7%, respectively. Furthermore, the as-prepared PC/HGMs composite foams have low thermal conductivity (lower than 0.07W/mK), which can effectively insulate heat propagation.
During the cultivation of crops, irrigation is included in necessary working operations like tillage, fertilization and sowing. For irrigation, we require the highest quality of work. Therefore, in ...this contribution, we focused on monitoring the quality of work of a hose reel irrigation machine. For determining the longitudinal uniformity of winding a hose on a reel, the development of a digital device was necessary. During the development, we had to design its two basic parts--the hardware and software. After construction of the device, its function was tested directly in working conditions of the particular reel hose irrigation machine. The results of our developed device were compared with the results of the Ecostar 4000 (Bauer, Austria) microcomputer, both with the same hose winding speed. On the microcomputer, we set the hose winding speed to +2.1 m*h.sup.-1. The average measured value of speed using the first device Speedmeter SM1 (2000, KSVS) was 11.7 m*h.sup.-1. The difference between the set and measured speed was 0.4 m*h.sup.-1 (absolute error of measurement, the relative error of measurement was 3.42 %). In the second case, the measurement was performed using a more modern device--Speedmeter SM2, which allows saving of results into its internal memory (2012, KSVS). The average measured value of winding speed was 12.26 m*h-1, which represents the relative error of measurement 2.77 % compared to the set value of 12.6 m*h-1. Based on the results obtained, we recommend the maintenance of the irrigation machine.
Photonic crystals (PCs) are nanomaterials with photonic properties made up of periodically modulated dielectric materials that reflect light between a wavelength range located in the photonic band ...gap. Colloidal PCs (C-PC) have been proposed for several applications such as optical platforms for the formation of physical, chemical, and biological sensors based on a chromatic response to an external stimulus. In this work, a robust protocol for the elaboration of photonic crystals based on SiOsub.2 particle (SP) deposition using the vertical lifting method was studied. A wide range of lifting speeds and particle suspension concentrations were investigated by evaluating the C-PC reflectance spectrum. Thinner and higher reflectance peaks were obtained with a decrease in the lifting speed and an increase in the SP concentrations up to certain values. Seven batches of twelve C-PCs employing a SP 3% suspension and a lifting speed of 0.28 µm/s were prepared to test the reproducibility of this method. Every C-PC fabricated in this assay has a wavelength peak in a range of 10 nm and a peak width lower than 90 nm. Inverse-opal polymeric films with a highly porous and interconnected morphology were obtained using the developed C-PC as a template. Overall, these results showed that reproducible colloidal crystals could be elaborated on a large scale with a simple apparatus in a short period, providing a step forward in the scale-up of the fabrication of photonic colloidal crystal and IO structures as those employed for the elaboration of photonic polymeric sensors.
Environmental problems caused by large amounts of COsub.2 generated by coal-electricity integration bases have raised concerns. To solve these problems, this study develops a COsub.2 foam concrete ...(CFC) material with both heat insulation and carbon fixation characteristics to realize COsub.2 in situ storage and utilization. In this study, a Portland-cement-based COsub.2 foam concrete (PC-CFC) with good thermal insulation performance and carbon fixation ability is prepared using carbonation pretreatment cement and a physical foaming method. The effects of COsub.2 on the compressive strength, thermal insulation, and carbon fixation properties of PC-CFC are studied. The internal relationship between the compressive strength, thermal insulation, and carbon fixation performance of PC-CFC is analyzed, and the feasibility of PC-CFC as a filling material to realize the in situ mineralization and storage of COsub.2 in the coal-electricity integration base is discussed. The experimental results show that the compressive strength of PC-CFC is significantly improved by COsub.2 curing. However, COsub.2 in the PC-CFC pores may weaken the strength of the pore structure, and the compressive strength decreases by 3.62% for each 1% increase in PC-CFC porosity. Using COsub.2 as a foaming gas and the physical foaming method to prepare CFC can achieve improved thermal insulation performance. The thermal conductivity of PC-CFC is 0.0512-0.0905 W/(m·K). In addition, the compressive strength of PC-CFC increases by 19.08% when the thermal conductivity of PC-CFC increases by 1%. On the premise of meeting the thermal insulation requirements, PC-CFC can achieve improved compressive strength. The carbon sequestration rate of the PC-CFC skeleton is 6.1-8.57%, and the carbon storage capacity of PC-CFC pores is 1.36-2.60 kg/ton, which has obvious carbon sequestration potential; however, the preparation process and parameters of PC-CFC still require further improvement. The research results show that PC-CFC has great potential for engineering applications and is of great significance for realizing carbon reduction at the coal-electricity integration base.
Photonic crystals (PCs) have promising characteristic to raise the light harvest of materials. PCs with one photonic band gap (PBG) were usually used to enhance the light harvest of materials. In ...this research work, we used PCs with dual PBGs to increase the light harvest. SiO.sub.2 PCs with dual PBGs were constructed through depositing a SiO.sub.2 PCs layer on another SiO.sub.2 PCs layer by vertical deposition method. Then the bi-layer structured SiO.sub.2 PCs were composited with nanocrystalline TiO.sub.2 film which was sensitized by CdS quantum dots (QDs) (Q-T), to produce photocatalyst for photodegradation of gaseous acetaldehyde. By adjusting the PBGs of the bi-layer SiO.sub.2 PCs, namely one PBG matching with the absorption edge of TiO.sub.2 and another PBG matching with the absorbing range of CdS QDs, the photocatalytic activity of the composite film under white light irradiation was increased to 2.11 times of that of the control photocatalyst (the Q-T film coated on a disordered porous SiO.sub.2 film). When Q-T film was coupled with a monolayer SiO.sub.2 PCs, which has single PBG centered at TiO.sub.2's electronic band gap (EBG) of 380 nm, its photocatalytic activity was increased by 1.34 times. When coupled with a monolayer SiO.sub.2 PC with the PBG centering at the EBG of CdS QDs (465 nm), the photo-catalytic activity of the Q-T film was increased by 1.54 times. Because the SiO.sub.2 PCs with dual-PBGs can simultaneously enhance the light harvest in ultraviolet and visible light region, the Q-T film coupled with dual-PBGs SiO.sub.2 PCs showed the highest activity.
Single-crystalline LiNi.sub.0.5Co.sub.0.2Mn.sub.0.3O.sub.2 (denoted as SC-523) with micron size had been successfully synthesized through a facile method. Electrochemical impedance spectroscopy and ...differential scanning calorimetry were carried out to identify the improved electrochemical performance and desired thermal stability. Even after 100 cycles, SC-523 still delivered a discharge capacity of 151.1 mA h g.sup.-1 (capacity retention with 90.3%) at 1 C in voltage range from 3.0 to 4.5 V (vs. Li/Li.sup.+), while polycrystalline spherical LiNi.sub.0.5Co.sub.0.2Mn.sub.0.3O.sub.2 (denoted as PC-523) only exhibited 141.7 mA h g.sup.-1 (capacity retention with 78.4%). Besides, SC-523 shows a higher decomposition temperature of 332.13 °C, 14.61 °C higher than that of PC-523 during the thermal decomposition. Consequently, single-crystalline particles with robust morphological integrity ensure the enhanced cycling stability and thermal stability.
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