A Novel Temperature Model of Regions Formed during the Preheating Stage of Belt Heating in Incremental Sheet Forming

The temperature of a forming region has a gradient distribution characteristic in the belt heating incremental sheet forming process, in which the relation between the heating power and the temperature distribution is ambiguous in the pre-heating stage. The setup of the heating power is therefore challenging, and the whole forming efficiency might decrease due to the above issue. Therefore, this paper proposes a belt heating method for electric conduction heating and presents a temperature calculation model for the forming region of the plate in the preheating state based on the heat conduction model. The calculated accuracy of the model is analysed through physical experiments, and the thermal transfer efficiency of heating tubes is analysed in detail. Based on the result, the thermal transfer efficiency value for heating tubes is determined to improve the accuracy of the suggested model. In addition, the effect of the model slope on the calculated result is further analysed, and the setting method of the slope value for the model is proposed according to different accuracy requirements

Fabrication and properties of zirconia/hydroxyapatite composite scaffold based on digital light processing

Zirconia and hydroxyapatite(HA) are two typical implant materials, which have the advantages of excellent mechanical strength and good biological activity respectively. It was found that composite material had good biocompatibility and mechanical strength compared to the single material. In this paper, the porous scaffolds of ZrO2/HA composite were formed by digital light processing (DLP) technology and their performance were evaluated. Cell experiments showed that the addition of HA had a positive effect on cell proliferation and differentiation. Mechanical tests showed that the composite scaffold with 10 wt% HA had the best compressive capacity due to the pinning and bridging effect of a small amount of HA grains. When scaffolds were immersed in the simulated body fluid (SBF), the compressive strengths of the composite scaffolds decreased within the first 14 days and gradually increased after 14 days. The reason for this phenomenon was the degradation of calcium phosphate components and the deposition of apatite. By the 28th day, the compressive strengths of all the composite scaffolds increased to over 20 MPa, close to that of the zirconia scaffolds during the same period (25 MPa). The compressive strengths of all scaffolds met the requirement of cancellous bone during the entire soaking period, and the composite scaffolds have potential application value in bone repair

Research on a Visual Electronic Nose System Based on Spatial Heterodyne Spectrometer

Light absorption gas sensing technology has the characteristics of massive parallelism, cross-sensitivity and extensive responsiveness, which make it suitable for the sensing task of an electronic nose (e-nose). With the performance of hyperspectral resolution, spatial heterodyne spectrometer (SHS) can present absorption spectra of the gas in the form of a two dimensional (2D) interferogram which facilitates the analysis of gases with mature image processing techniques. Therefore, a visual e-nose system based on SHS was proposed. Firstly, a theoretical model of the visual e-nose system was constructed and its visual maps were obtained by an experiment. Then the local binary pattern (LBP) and Gray-Level Co-occurrence Matrix (GLCM) were used for feature extraction. Finally, classification algorithms based on distance similarity (Correlation coefficient (CC); Euclidean distance to centroids (EDC)) were chosen to carry on pattern recognition analysis to verify the feasibility of the visual e-nose system

Terahertz photoconductive antenna with all-dielectric nanopillars

Photoconductive antennas (PCAs), as a popular terahertz (THz) radiation source, have been widely used in spectroscopy, material characterization, biological imaging and detection of hazardous materials. However, PCAs have a relatively low energy conversion efficiency from femtosecond laser pulses to THz radiation which often limits the signal-to-noise ratio and bandwidth of THz imaging and spectroscopy systems. To address these limitations, here we report a THz photoconductive antenna emitter with all-dielectric nanopillars integrated on top of the SI-GaAs substrate to increase the generated photocarriers, which achieves a broadband and frequency insensitive THz power enhancement factor around 1.25 at frequencies 0.05 - 1.6 THz. Our results reported here provide a new method for increasing the THz power of PCAs, which paves the way for the subsequent researches of next-generation PCAs

A Novel Minimal Invasive Mouse Model of Extracorporeal Circulation

Extracorporeal circulation (ECC) is necessary for conventional cardiac surgery and life support, but it often triggers systemic inflammation that can significantly damage tissue. Studies of ECC have been limited to large animals because of the complexity of the surgical procedures involved, which has hampered detailed understanding of ECC-induced injury. Here we describe a minimally invasive mouse model of ECC that may allow more extensive mechanistic studies. The right carotid artery and external jugular vein of anesthetized adult male C57BL/6 mice were cannulated to allow blood flow through a 1/32-inch external tube. All animals (n=20) survived 30 min ECC and subsequent 60 min observation. Blood analysis after ECC showed significant increases in levels of tumor necrosis factor α, interleukin-6, and neutrophil elastase in plasma, lung, and renal tissues, as well as increases in plasma creatinine and cystatin C and decreases in the oxygenation index. Histopathology showed that ECC induced the expected lung inflammation, which included alveolar congestion, hemorrhage, neutrophil infiltration, and alveolar wall thickening; in renal tissue, ECC induced intracytoplasmic vacuolization, acute tubular necrosis, and epithelial swelling. Our results suggest that this novel, minimally invasive mouse model can recapitulate many of the clinical features of ECC-induced systemic inflammatory response and organ injury

Molecular Enhancement of Direct Electrolysis of Dilute CO₂

Producing chemicals and fuels via direct electrolysis of dilute CO2 derived from industrial point sources can improve the economic feasibility of CO2 electrolysis technology, yet it suffers from many challenges owing to unfavorable mass transport, reaction thermodynamics, and kinetics. Here we report a molecular enhancement strategy for direct electrolysis of a dilute CO2 stream with a 10% concentration in typical flue gas, using a commercially available cobalt phthalocyanine (CoPc) catalyst. A poly(4-vinylpyridine) (P4VP)-modified CoPc electrode exhibits a remarkable CO partial current density of 252 mA cm–2 with a CO Faradaic efficiency of 90% under the dilute CO2 feed, 2.24-fold higher than that of the bare CoPc electrode. The integration of the CoPc molecule and the P4VP modifier with abundant pyridine moieties creates a reaction microenvironment for sequentially capturing and activating CO2, thus resulting in impressive electrocatalytic performance. The presented molecular enhancement strategy paves the way for direct utilization of a dilute CO2 stream from industrial flue gas