Hydrogen sensing performance of silica microfiber elaborated with Pd nanoparticles

A hydrogen sensor has been proposed by coating Pd nanoparticles-PMMA composite organic sol on silica microfiber independent on any expensive or complex chemical process. The thickness of cladding layer and the diameter of elaborated microfiber were determined as ∼20 μm and ∼57.93 μm, respectively. Due to the evanescent wave excited by silica microfiber and the amorphous structure of PMMA film, the Pd nanoparticles effectively absorbed the hydrogen molecules and resulted in the shift of resonance wavelength. The experimental results match well with an exponential curve with an average sensitivity of 5.58 nm/%, which is comparable to other electrochemical hydrogen sensors reported recently.The authors thank the support from the National Natural Science Foundation of China (NSFC) under Grants (61405032, 61403074, 61605031); and Doctoral Scientific Research Startup Foundation of Liaoning Province under Grant (201501144); and Fundamental Research Funds for the Central Universities under Grants (N150404022, N150401001); and China Scholarship Council (201606085023)

Memetic-Based Schedule Synthesis for Communication on Time-Triggered Embedded Systems

ime-triggered systems play an important role in industrial embedded systems. The time-triggered network is deployed on the time-triggered network-on-chip implementation. It ensures the safety-critical industrial communication for real-time embedded multiprocessor systems. To guarantee the safety-critical requirements for communication, each message is transmitted by a predefined static schedule. However, synthesizing a feasible schedule is a challenge because both spatial and temporal constraints should be considered. This article presents a novel memetic-based schedule synthesis algorithm to derive a feasible schedule by determining the offset of messages on the time-triggered network-on-chip. Memetic-based schedule synthesis algorithm is based on memetic algorithm, which incorporates local search in the iterations of general genetic algorithm. We compare memetic-based schedule synthesis algorithm with genetic algorithm in different scale of time-triggered network-on-chip and number of messages. The experimental results show that the memetic-based schedule synthesis algorithm is effective to synthesize a feasible schedule, and the failure schedule synthesized by memetic-based schedule synthesis algorithm is only 34.2% in average compared to the conventional genetic algorithm

Recent developments in electrochemical sensors based on nanomaterials for determining glucose and its byproduct H2O2

The development in glucose and H2O2 electrochemical sensors has significantly progressed using some original nanomaterials, such as nanoparticles and nanowires in metal, metal oxide, or carbon nanomaterials. In this review, we discussed and analyzed the mechanism, performance, and characteristics of the enzyme/nonenzyme glucose and H2O2 electrochemical sensors based on some pure metal (Au, Pd, Ni, Pt, and Cu), metal oxide (ZnO, NiO, CuO (x) , TiO2, and Co3O4), and carbon (nanotubes and graphene) nanomaterials. Although the introduction of nanomaterials can effectively improve the sensitivity of enzyme glucose/H2O2 sensors by enhancing the activity of protein enzyme, the enzymes are sensitive to the biochemical environment. Meanwhile, the sensing performance of nonenzyme glucose/H2O2 sensors significantly depends on the morphology, uniformity, and distribution of nanomaterials.This work was supported by the National Natural Science Foundation of China (NSFC) under Grants (Numbers 61405032, 61403074, 61605031, 61425003); and Doctoral Scientific Research Startup Foundation of Liaoning Province under Grant (Number 20150 1144); and Fundamental Research Funds for the Central Universities under Grants (Numbers N1504 04022, N150401001). Jin Li acknowledges the financial support from the China Scholarship Council for his Research Scholarship No. 201606085023

Refractive index sensor based on silica microfiber doped with Ag microparticles

We proposed a composite microfiber using silica capillary and Ag microparticles, and demonstrated its optical sensing characteristics by changing the refractive index of surrounding environment using different concentrations of NaCl solution. Either the diameter or doping density of Ag microparticles contributes to the sensitivity change. The experimental results reveal that the diameter uniformity and distribution of Ag microparticles exerted impact on the sensing performance. The highest sensitivity of −7246 dB/RIU has been experimentally demonstrated in this work. The selectivity of this composite microfiber sensor will be explored by decorating its surface with some enzyme or other sensitive materials.This work was supported by the National Natural Science Foundation of China (NSFC) under Grants (number 61405032, 61403074, 61605031, 11504072); and Doctoral Scientific Research Startup Foundation of Liaoning Province under Grant (number 201501144); and Fundamental Research Funds for the Central Universities under Grants (number N150404022, N150401001). Jin Li acknowledges the financial support from the China Scholarship Council for his Visiting Scholarship No. 201606085023

Ultrasonic Phased Array Sparse-TFM Imaging Based on Sparse Array Optimization and New Edge-Directed Interpolation

The ultrasonic phased array total focusing method (TFM) has the advantages of full-range dynamic focusing and high imaging resolution, but the problem of long imaging time limits its practically industrial applications. To reduce the imaging calculation demand of TFM, the locations of active array elements in the sparse array are optimized by combining almost different sets with the genetic algorithm (ADSGA), and corrected based on the consistency of the effective aperture with the equivalent point diffusion function. At the same time, to further increase the imaging efficiency, a sparse-TFM image with lower resolution is obtained by reducing the number of focus points and then interpolated by the new edge-directed interpolation algorithm (NEDI) to obtain a high quality sparse-TFM image. Compared with TFM, the experimental results show that the quantitative accuracy of the proposed method is only decreased by 1.09% when the number of sparse transmitting elements reaches 8 for a 32-element transducer, and the imaging speed is improved by about 16 times with the same final pixel resolution

Study for Longitudinal Deformation of Shield Tunnel in Side of Foundation Pit Based on Virtual Image Technique

A prediction model of enclosure structure deformation caused by the excavation of foundation pit is established. Based on the virtual image technique, the soil deformation caused by sidewall deformation is calculated. Meanwhile, the deformation model considering rotating and staggering of shield tunnel is used to establish a calculation method of longitudinal deformation of adjacent shield tunnel. The result suggests that: (a) The horizontal displacement of adjacent shield tunnel is normally distributed. (b) With increasing retaining structure deformation, it is obvious that deformation value and range of adjacent shield tunnel also increase. (c) As the distance between the adjacent shield tunnel and the enclosure structure increases, the horizontal displacement of the side shield tunnel decreases nonlinearly. (d) The shield tunnel with shallow buried depth is greatly affect by the excavation of adjacent foundation pit. As the depth of the tunnel increases, the impact gradually decreases

Intracystic papillary carcinoma of the breast in a male patient

We report a case of intracystic papillary carcinoma of the right breast in a 59-year old man presenting with bloody nipple discharge for 1 week prior to presentation. Mammography, ultrasonography, and core needle aspiration were consistent with intracystic papillary carcinoma. The patient underwent right simple mastectomy. Pathology was also consistent with low grade intracystic papillary carcinoma. A 21-gene assay revealed a recurrence score of 0, corresponding to a 3% risk of distant recurrence at 10 years. The patient did not receive chemotherapy or post-mastectomy radiotherapy. The patient was placed on tamoxifen and has been free of disease to date

Numerical simulations of arbitrary evolving cracks in geotechnical structures using the nonlinear augmented finite element method (N-AFEM)

This paper presents an integrated numerical algorithm based on the nonlinear augmented finite element method (N-AFEM) to accurately simulate the arbitrary evolving strong discontinuities (cracks/slip lines) and failure behaviors in geotechnical structures. A novel nonlinear elemental augmentation and condensation scheme was first proposed within the N-AFEM framework, which allows the consideration of nonlinear coupled intra-element cracks without the need of additional nodes or nodal DoFs. Then a modified exponential cohesive zone model (CZM) that considers the coupling effects between tension/compression and shear at the fracture surface was proposed to describe the fracture process of geomaterials. Besides, a nonlinear yielding function based on the Mohr-Coulomb strength theory was introduced into the framework and serves as the fracture initiation criteria for geomaterials. Finally, several benchmark examples were simulated and the predicted results were compared with existing numerical or experimental data to demonstrate the validity of the proposed method. •A nonlinear elemental augmentation scheme is proposed to account for intra-element cracks without additional nodal DoFs.•A CZM that considers the coupling effects between tension/compression and shear at the fracture surface is formulated.•A nonlinear yield function based on Mohr-Coulomb theory is introduced as fracture initiation criteria for geomaterials.•The fracture behaviors and failure mechanisms of several benchmark examples are investigated in detail

An improved crack-tip element treatment for advanced FEMs

•An improved crack-tip element treatment for those advanced FEMs is proposed.•The improved treatment is integrated into the augmented finite element method.•Examples at elemental/structural level are used to verify the proposed treatment.•Results from the improved treatment are more reasonable and high accuracy. This paper presents an improved treatment for those advanced FEMs that use stresses in the crack-tip element for evaluation crack propagation condition. We show that the common treatment of obtaining crack-tip displacements using simple interpolation from the edge of the crack-tip element is inaccurate and is responsible for the jagged jump and unwarping behavior (JJU) frequently reported in literature. In this study we propose a more accurate treatment by introducing an element node with independent degree of freedom (DoF) to enrich the crack-tip element. We show that the proposed approach can relieve the stiffness overestimation of the crack-tip element without disrupting the standard element interpolation process. Results of numerical examples demonstrate that the improved treatment can greatly improve the stress shielding phenomenon and effectively reduce the JJU in load-displacement curves