2D molybdenum disulfide (MoS2)-based thin film transistors are widely used in biosensing, and many efforts have been made to improve the detection limit and linear range. However, in addition to the complexity of device technology and biological modification, the compatibility of the physical device with biological solutions and device reusability have rarely been considered. Herein, we designed and synthesized an array of MoS2 by employing a simple-patterned chemical vapor deposition growth method and meanwhile exploited a one-step biomodification in a sensing pad based on DNA tetrahedron probes to form a bio-separated sensing part. This solves the signal interference, solution erosion, and instability of semiconductor-based biosensors after contacting biological solutions, and also allows physical devices to be reused. Furthermore, the gate-free detection structure that we first proposed for DNA (BRCA1) detection demonstrates ultrasensitive detection over a broad range of 1 fM to 1 μM with a good linear response of R2 = 0.98. Our findings provide a practical solution for high-performance, low-cost, biocompatible, reusable, and bio-separated biosensor platforms.
Modern gas turbine rotors are usually designed as combined rotors in which disks are tied together by one central tie rod or several tie rods distributed along the circumference. This structure has the advantages in cooling design, light weight and processing assembly, however it brings some problems and challenges in predicting the dynamic characteristics of rotor. No matter how many tie rods are used to fasten the disks, the rotor is not an integral or continuous structure any more. The contact effects between contact faces and the pre-tightening forces of tie rods have great influence on the rotor’s dynamic behaviors. Traditional methods to calculate the critical speed in rotor dynamics such as Transfer Matrix Method and 2-D Finite Element Method (FEM), based on the integral and continuous rotor, fail to consider factors of the contact effects and the pre-tightening forces of tie rods. Although the 3-D FEM can exactly calculate the critical speed, it is still time and resource consuming to establish and calculate such complex three-dimensional structures, even on the most advanced computers at present. In this paper, the traditional 2-D FEM is improved by considering the contact effects and pre-tightening forces of tie rods. Contact faces in the rotor are dealt as elements with equivalent stiffness but without mass, thus the rotor-bearing system of gas turbine are composed of contact elements, elastic elements, rigid disk elements and bearing elements. According to the improved 2-D FEM, a program is developed to calculate the critical speed and unbalance response of gas turbine rotors. The equivalent stiffness, serving as an important input parameter in the program and elements in the stiffness matrix of the system, is mainly determined by the contact stiffness between contact faces and the pre-tightening force. To find out relationships between them, GW (Greenwood and Williamson) statistical model is used and the equivalent stiffness of complex contact faces is obtained. According to the results, certain curves showing the relationship between equivalent stiffness of contact surface and pre-tightening force are obtained. By these curves and the program, we can easily calculate the dynamic characteristics of gas turbine rotors with satisfying accuracy and less time. To validate this method, the critical speed of a real rotor of a certain gas turbine was calculated with the program and curves, and the results agree well with the measured data.
With the assistance of a ferroelectric field created by a ferroelectric polymer, the performance of perovskite photo transistors is significantly improved.
Aims and Background Hepatocellular carcinoma (HCC) is a dismal malignancy associated with multiple molecular changes. The purpose of this study was to identify the differentially expressed genes and analyze the biological processes related to HCC. Methods and Study Design Datasets of HCC were obtained from the NCBI Gene Expression Omnibus. Integrated analysis of differentially expressed genes was performed using the INMEX program. Then Gene Ontology enrichment analyses and pathway analysis were performed based on the Gene Ontology website and Kyoto Encyclopedia of Genes and Genomes. A protein-protein interaction network was constructed using the Cytoscape software; the netwerk served to find hub genes for HCC. Real-time RT-PCR was used to validate the microarray data for hub genes. Results We identified 273 genes that were differentially expressed in HCC. Gene Ontology enrichment analyses revealed response to cadmium ion, cellular response to cadmium ion, and cellular response to zinc ion for these genes. Pathway analysis showed that significant pathways included fatty acid metabolism, butanoate metabolism, and PPAR signaling pathway. The protein-protein interaction network indicated that CDH1, ECHS1, ACAA1, MT2A, and MYC were important genes which participated in many interactions. Experimental validation of the role of four upregulated genes ( ECHS1, ACAA1, MT2A and MYC) in the progression of HCC was carried out. Conclusions Our study displayed genes that were consistently differentially expressed in HCC. The biological pathways and protein-protein interaction networks associated with those genes were also identified. We predicted that CDH1, ECHS1, ACAA1, MT2A, and MYC might be target genes for diagnosing HCC.
In order to ensure the safety of the structure design for the polycrystalline silicon reduction furnace and conduct the regulating and controling of the cooling systems in operation,it is nesscessary to master the temperature distribution of all parts in operation comprehensively.It describes the reasarch of the heat transfer coupling temperature simulation invovled radiation,heat conduction and convection,which is combined with the RD of a Large-Scale polycrystalline silicon furnace.The 3-dimentional model is constructed by Unigraphics~and the temperature calculating contained radiative heat transfer inside the hearth,the convective heat transfer in the cooling systems and heat conduction in all metal and non-metal parts are carried on the numerical simulation bench of ANSYS CFX~.By Comparing with the physical model of the furnace,it has shown that the temperature simulation is enough reliable and accurate to conduct the control of the technological parameters.The results of the simulation could be used as the temper-ature boundary conditions in the thermal-structure coupling analysis,which could be used to evaluate the safety of furnace under working condition of the high temperature and high pressure.
We reported the spectral extension to 1.65 μm far beyond the λ cutoff of 870 nm. Ultrahigh R and D * above 3.84 A W −1 and 3.73 × 10 11 Jones, respectively, are realized, illustrating strong competitiveness with Si, Ge and InGaAs commercial detectors.
Electronic properties of two-dimensional (2D) materials can be significantly tuned by an external electric field. Ferroelectric gates can provide a strong polarization electric field. Here, we report the measurements of the band structure of few-layer MoS2 modulated by a ferroelectric P(VDF-TrFE) gate with contact-mode scanning tunneling spectroscopy. When P(VDF-TrFE) is fully polarized, an electric field up to ∼0.62 V/nm through the MoS2 layers is inferred from the measured band edges, which affects the band structure significantly. First, strong band bending in the vertical direction signifies the Franz-Keldysh effect and a large extension of the optical absorption edge. Photons with energy of half the band gap are still absorbed with 20% of the absorption probability of photons at the band gap. Second, the electric field greatly enlarges the energy separations between the quantum-well subbands. Our study intuitively demonstrates the great potential of ferroelectric gates in band structure manipulation of 2D materials.
Organic-inorganic hybrid semiconducting (OIHS) materials, which can detect broader spectral regions, are highly desired in several applications including biomedical imaging, night vision, and optical communications. Although lead (Pb)-halide perovskites have reached a mature research stage, high toxicity of Pb hinders their large-scale viability. Tin (Sn)-based perovskites are the most common OIHS broadband light absorbers that replace toxic Pb; however, they are extremely unstable due to the notorious Sn
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