28 research outputs found

    A Study on the Quality Monitoring of County Education

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    Study on Power Switching Process of a Hybrid Electric Vehicle with In-Wheel Motors

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    Hybrid electric vehicles with in-wheel motors (IWM) achieve a variety of driving modes by two power sources—the engine and the IWM. One of the critical problems that exists in such vehicle is the different transient characteristics between the engine and the IWM. Therefore, switching processes between the power sources have noteworthy impacts on vehicle dynamics and driving performance. For the particular switching process of the pure electric mode to the engine driving mode, a specific control strategy coordinating clutch torque, motor torque, and engine torque was proposed to solve drivability issues caused by inconsistent responses of different power sources during the mode transition. The specific switching process could be described as follows: the engine was started by IWM with the clutch serving as a key enabling actuator, dynamic torque compensation through IWM was implemented after engine started, and, meanwhile, engine speed was controlled to track the target speed through the closed loop PID control strategy. The bench tests results showed that the vehicle jerk caused during mode switching was reduced and fast and smooth mode switching was realized, which leads to the improvement of vehicle’s riding comfort

    A Nonenzymatic Glucose Sensor Platform Based on Specific Recognition and Conductive Polymer-Decorated CuCo2O4 Carbon Nanofibers

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    CuCo2O4 decoration carbon nanofibers (CNFs) as an enzyme-free glucose sensor were fabricated via electrospinning technology and carbonization treatment. The CNFs with advantages of abundant nitrogen amounts, porosity, large surface area, and superior electrical conductivity were used as an ideal matrix for CuCo2O4 decoration. The resultant CuCo2O4–CNF hybrids possessed favorable properties of unique three-dimensional architecture and good crystallinity, accompanied by the CuCo2O4 nanoparticles uniformly growing on the CNF skeleton. To further enhance the selective molecular recognition capacity of the developed sensor, a conductive film was synthesized through the electropolymerization of thiophene and thiophene-3-boronic acid (TBA). Based on the synergistic effects of the performances of CNFs, CuCo2O4 nanoparticles, and boronic acid-decorated polythiophene layer, the obtained poly(thiophene-3-boronic acid) (PTBA)/CuCo2O4–CNF-modified electrodes (PTBA/CuCo2O4–CNFs/glassy carbon electrode (GCE)) displayed prominent electrocatalytic activity toward electro-oxidation of glucose. The fabricated sensor presented an outstanding performance in the two linear ranges of 0.01–0.5 mM and 0.5–1.5 mM, with high selectivity of 2932 and 708 μA·mM−1·cm−2, respectively. The composite nanofibers also possessed good stability, repeatability, and excellent anti-interference selectivity toward the common interferences. All these results demonstrate that the proposed composite nanofibers hold great potential in the application of constructing an enzyme-free glucose sensing platform

    Design, Fabrication and Characterization of a MEMS-Based Three-Dimensional Electric Field Sensor with Low Cross-Axis Coupling Interference

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    One of the major concerns in the development of three-dimensional (3D) electric field sensors (EFSs) is their susceptibility to cross-axis coupling interference. The output signal for each sensing axis of a 3D EFS is often coupled by electric field components from the two other orthogonal sensing axes. In this paper, a one-dimensional (1D) electric field sensor chip (EFSC) with low cross-axis coupling interference is presented. It is designed to be symmetrical, forming a pair of in-plane symmetrically-located sensing structures. Using a difference circuit, the 1D EFSC is capable of sensing parallel electric fields along symmetrical structures and eliminating cross-axis coupling interference, which is contrast to previously reported 1D EFSCs designed for perpendicular electric field component measurement. Thus, a 3D EFS with low cross-axis coupling interference can be realized using three proposed 1D EFSCs. This 3D EFS has the advantages of low cross-axis coupling interference, small size, and high integration. The testing and calibration systems of the proposed 3D EFS were developed. Experimental results show that in the range of 0–120 kV/m, cross-axis sensitivities are within 5.48%, and the total measurement errors of this 3D EFS are within 6.16%

    A High Sensitivity Electric Field Microsensor Based on Torsional Resonance

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    This paper proposes a high sensitivity electric field microsensor (EFM) based on torsional resonance. The proposed microsensor adopts torsional shutter, which is composed of shielding electrodes and torsional beams. The movable shielding electrodes and the fixed sensing electrodes are fabricated on the same plane and interdigitally arranged. Push–pull electrostatic actuation method is employed to excite the torsional shutter. Simulation results proved that the torsional shutter has higher efficiency of charge induction. The optimization of structure parameters was conducted to improve its efficiency of charge induction further. A micromachining fabrication process was developed to fabricate the EFM. Experiments were conducted to characterize the EFM. A good linearity of 0.15% was achieved within an electrostatic field range of 0–50 kV/m, and the uncertainty was below 0.38% in the three roundtrip measurements. A high sensitivity of 4.82 mV/(kV/m) was achieved with the trans-resistance of 100 MΩ, which is improved by at least one order of magnitude compared with previously reported EFMs. The efficiency of charge induction for this microsensor reached 48.19 pA/(kV/m)

    Correlation analysis of clinical, pathological, imaging and genetic features of ground-glass nodule featured lung adenocarcinomas between high-risk and non-high-risk individuals

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    Abstract Background Early stage lung adenocarcinomas manifested as ground-glass nodules (GGNs) are increasingly being detected, but screening and diagnosis for GGN-featured lung adenocarcinomas in different risk populations reach no agreement. Objectives To analyze the clinical, pathological, imaging and genetic features of GGN-featured lung adenocarcinomas on high-resolution computed tomography (HRCT) in different risk groups. Methods Include patients with GGNs on HRCT surgically diagnosed as lung adenocarcinoma in the West China Hospital, Sichuan University from 2009 to 2021, and their clinical, pathological, imaging and gene sequencing data. Results According to Chinese Expert Consensus on Screening and Management of Lung Cancer, 1,800 patients with GGN-featured lung adenocarcinoma, 545 males (incl. 269 smokers) and 1,255 females (incl. 16 smokers), were divided into high-risk (509) and non-high-risk (1,291) groups. Among them, 1,095 were detected via physical examination. The mean age at diagnosis was 54.78 (23–84) and the mean time from detection to diagnosis was 9.59 months. There were more males than females in the high-risk group [288 (56.58%) vs 221 (43.42%)], just the opposite in the non-high-risk group [1,034 (80.09%) vs 257 (19.91%)] (both P  0.05). The frequency of invasive adenocarcinoma was higher in the high-risk group, while those of precursor lesions and minimally invasive adenocarcinoma were higher in the non-high-risk group (all P < 0.001). The preoperative follow-up time in the non-high-risk group was shorter (P < 0.05). A total of 711 gene mutations were observed in 473 patients with a ratio of non-high-risk to high-risk of 494:217. The incidence of EGFR mutation was not statistically significant (P = 0.824), while those of TP53 and KRAS mutations were higher in the high-risk group (P < 0.05). Conclusions GGN-featured lung adenocarcinoma is dominated by non-high-risk female patients. Shorter preoperative follow-up in the non-high-risk group and no statistical difference in GGN detection way suggests the existing screening criteria for high-risk population may not suit GGN-featured lung cancer. In addition, the incidences of KRAS and TP53 mutations are higher in the high-risk group

    Highly Efficient Adsorption of Heavy Metals onto Novel Magnetic Porous Composites Modified with Amino Groups

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    A novel porous magnetic composite CoFe<sub>2</sub>O<sub>4</sub>–SiO<sub>2</sub> (CF–S) was prepared by a simple template method. After facile amino-functionalization, it exhibited bigger adsorption capacity and higher removal efficiency (>90%) for all the heavy metal ions (Cu­(II), Mn­(II), Cd­(II), and Pb­(II)) in single or mixed metal ions solution. The adsorption affinity for heavy metal ions was not much impacted by the presence of competitive ions. Moreover, effects of experimental parameters, including adsorbent dosage, solution pH, initial concentration, reaction temperature and time, were discussed. The isothermal adsorption results were well described by the Langmuir model, and the maximum adsorption capacities were 429.18 mg·g<sup>–1</sup> (25 °C), 500.00 mg·g<sup>–1</sup> (35 °C), 523.56 mg·g<sup>–1</sup> (45 °C), and 555.51 mg·g<sup>–1</sup> (55 °C) for Cu­(II) ions. The adsorption kinetics fitted well with pseudo-second order kinetic model. Analysis of thermodynamic study for Cu­(II) showed that the process of adsorption was spontaneous and endothermic in nature. The results indicated that the excellent adsorption was attributed to chemical adsorption through strong surface complexation, as well as the special structure of the CF–S–N composite

    Double molecular recognition ligands modified CPDS/CMCS/Fe3O4-rGO hybrid with enhanced enrichment capacity for glycoproteins at neutral environment

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    In order to achieve specific enrichment of target glycoproteins, double molecular recognition ligands functionalized surface solid-phase adsorption materials that can play a role under physiological pH conditions, have obvious advantages. In this work, a novel strategy was proposed for the synthesis of double molecular recognition functionalized magnetic graphene nanocomposites. Horseradish peroxidase was selected as the template proteins for evaluating the selectivity and binding capacity of the adsorption material. The bimolecular recognition was realized by introducing 4-carboxyphenylboronic acid (CPBA) and Suberic acid bis(3-sulfo-N-hydroxysuccinimide ester) sodium salt (Sulfo-DSS) as functional ligands. The abundant oxygen-containing groups in the complex (abbreviated as CPDS/CMCS/Fe3O4-rGO) were beneficial to reduce the pKa value of CPBA. Finally, CPDS/CMCS/Fe3O4-rGO realized the selective adsorption of glycoproteins in the neutral environment (pH 7.0). The resultant CPDS/CMCS/Fe3O4-rGO exhibited a high adsorption capacity of 1280.6 mg g−1 and excellent specificity toward glycoproteins compared to nonglycoproteins. Moreover, CPDS/CMCS/Fe3O4-rGO with strong magnetic responses (59.29 emu·g−1), could achieve rapid aggregation and separation under the external magnetic field. The results demonstrated the great potential of CPDS/CMCS/Fe3O4-rGO composites to separate and enrich glycoproteins from the complex biological sample for the glycoproteins analysis
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