Search

In this study, the equivalent bending stiffness of cement-bonded joints connecting the porcelain bushing and flange in ultra-high voltage (UHV) electrical equipment was investigated. A mechanical bending model of the joint was developed based on its structural features, and a new equation for the equivalent bending stiffness of the joint was proposed. Based on experimental data for nine UHV porcelain bushings, a dimensionless elasticity coefficient for the equivalent bending stiffness equation was determined. Finally, considering two 1000 kV arresters as examples, the bending stiffness was calculated using the equation proposed in this paper and that which is used in China's seismic code. A comparison of the results shows that the equation proposed in this study is in better agreement with the experimental data. Compared with the code equation, the equation in this paper adopts the expression for the dimensionless coefficient, which can more reasonably reveal the bending mechanism of the joint. [ABSTRACT FROM AUTHOR]

This paper aims to optimize the design of overburden thickness for underground arsenals. The dynamic finite-element program ANSYS/LS-DYNA was adopted to numerically simulate the damage and failure process of two types of rocks (i.e., marble and granite) with different sizes and lithologies under the explosion load. The simulated results were verified against the data of a previous explosion test. The simulation was found to be reliable, for the simulated results agreed well with the test data. Based on the collected data, the authors thoroughly analyzed the damage effect of underground explosion on the cave under different overburden thicknesses and charge densities. The results show that the overburden thickness directly affects the limiting effect of the outer rock on the particle vibration of the inner rock; the vibration intensity on the free surface is significantly negatively correlated with the overburden thickness; the damage of underground caves has a steep nonlinear relationship with charge density. The research findings provide a guide for the future design of overburden thickness for underground arsenals. [ABSTRACT FROM AUTHOR]

Motion pose capture technology can effectively solve the problem of difficulty in defining character motion in the process of 3D animation production and greatly reduce the workload of character motion control, thereby improving the efficiency of animation development and the fidelity of character motion. Motion gesture capture technology is widely used in virtual reality systems, virtual training grounds, and real-time tracking of the motion trajectories of general objects. This paper proposes an attitude estimation algorithm adapted to be embedded. The previous centralized Kalman filter is divided into two-step Kalman filtering. According to the different characteristics of the sensors, they are processed separately to isolate the cross-influence between sensors. An adaptive adjustment method based on fuzzy logic is proposed. The acceleration, angular velocity, and geomagnetic field strength of the environment are used as the input of fuzzy logic to judge the motion state of the carrier and then adjust the covariance matrix of the filter. The adaptive adjustment of the sensor is converted to the recognition of the motion state. For the study of human motion posture capture, this paper designs a verification experiment based on the existing robotic arm in the laboratory. The experiment shows that the studied motion posture capture method has better performance. The human body motion gesture is designed for capturing experiments, and the capture results show that the obtained pose angle information can better restore the human body motion. A visual model of human motion posture capture was established, and after comparing and analyzing with the real situation, it was found that the simulation approach reproduced the motion process of human motion well. For the research of human motion recognition, this paper designs a two-classification model and human daily behaviors for experiments. Experiments show that the accuracy of the two-category human motion gesture capture and recognition has achieved good results. The experimental effect of SVC on the recognition of two classifications is excellent. In the case of using all optimization algorithms, the accuracy rate is higher than 90%, and the final recognition accuracy rate is also higher than 90%. In terms of recognition time, the time required for human motion gesture capture and recognition is less than 2 s. [ABSTRACT FROM AUTHOR]

In vivo loose patch and breakthrough whole-cell recordings are useful tools for investigating the intrinsic and synaptic properties of neurons. However, the correlation among pipette resistance, seal condition, and recording time is not thoroughly clear. Presently, we investigated the recording time of different pipette resistances and seal conditions in loose patch and breakthrough whole-cell recordings. The recording time did not change with pipette resistance for loose patch recording (R p-loose) and first increased and then decreased as seal resistance for loose patch recording (R s-loose) increased. For a high probability of a recording time ≥30 min, the low and high cutoff values of R s-loose were 21.5 and 36 MΩ, respectively. For neurons with R s-loose values of 21.5–36 MΩ, the action potential (AP) amplitudes changed slightly 30 min after the seal. The recording time increased as seal resistance for whole-cell recording (R s-tight) increased and the zero-current membrane potential for breakthrough whole-cell recording (MPzero-current) decreased. For a high probability of a recording time ≥30 min, the cutoff values of R s-tight and MPzero-current were 2.35 GΩ and −53.5 mV, respectively. The area under the curve (AUC) of the MPzero-current receiver operating characteristic (ROC) curve was larger than that of the R s-tight ROC curve. For neurons with MPzero-current values ≤ −53.5 mV, the inhibitory or excitatory postsynaptic current amplitudes did not show significant changes 30 min after the seal. In neurons with R s-tight values ≥2.35 GΩ, the recording time gradually increased and then decreased as the pipette resistance for whole-cell recording (R p-tight) increased. For the high probability of a recording time ≥30 min, the low and high cutoff values of R p-tight were 6.15 and 6.45 MΩ, respectively. Together, we concluded that the optimal R s-loose range is 21.5–36 MΩ, the optimal R p-tight range is 6.15–6.45 MΩ, and the optimal R s-tight and MPzero-current values are ≥2.35 GΩ and ≤ −53.5 mV, respectively. Compared with R s-tight, the MPzero-current value can more accurately discriminate recording times ≥30 min and <30 min. [ABSTRACT FROM AUTHOR]

In auditory-conditioned fear learning, the freezing response is independent of the sound frequencies used, but the frequency of the conditioned sound is considered distinct from those of unrelated sounds based on electrophysiological responses in the auditory system. Whether an emergent discriminative learning underlies auditory fear conditioning and which nuclei and pathways are involved in it remain unclear. Using behavioral and electrophysiological assays, we found that the response of medial prefrontal cortex (mPFC) neurons to a conditioned auditory stimulus (CS) was enhanced relative to the response to unrelated frequencies (UFs) after auditory fear conditioning, and mice could distinguish the CS during multifrequency testing, a phenomenon called emergent discriminative learning. After silencing the mPFC with muscimol, emergent discriminative learning was blocked. In addition, the pure tone responses of mPFC neurons were inhibited after injection of lidocaine in the ipsilateral primary auditory cortex (A1), and the emergent discriminative learning was blocked by silencing both sides of A1 with muscimol. This study, therefore, provides evidence for an emergent discriminative learning mediated by mPFC and A1 neurons after auditory fear conditioning. [ABSTRACT FROM AUTHOR]

Variable-temperature Fourier transform infrared spectroscopy was used to investigate matrix-nanofiller interactions in amorphous semiaromatic polyamide/layered silicate nanocomposites prepared by melt intercalation. The types of polymer-nanofiller interactions were found to be strongly dependent on the nature of the polymer matrix and the surfactant-modified layered silicate. Improved compatibility resulted when hydrogen-bonding interactions occurred between the surfactant and polymer chains. The presence of surfactants with phenyl groups also led to a more stable molecular structure of the polymer matrix because of the enhanced resonance effect between aromatic groups. SiO stretching vibrations in the layered silicate shifted to lower wavenumbers with increasing temperature; this indicated the presence of weaker polymer-layered silicate interactions. The results of this study demonstrate that for the polymer nanocomposites prepared by melting intercalation, more important interfacial interactions existed between the polymer and the surfactant. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

Fourier transform infrared (FTIR) spectroscopy was used to characterize the state of dispersion of layered silicate in polymer nanocomposites. The nanocomposite samples were based on poly(hexamethylene isophthalamide) and montmorillonite nanoclay prepared by melt intercalation. The infrared spectra of SiO stretching bands between 1150 and 960 cm−1 are found to be very sensitive to the extent of nanoclay dispersion at the molecular level. Increased level of nanoclay delamination resulted in significant changes to the out-of-plane a [ABSTRACT FROM AUTHOR]

Zhang, X.-G.; Zhu, J.-X.; Zeng, Y.; Jiang, P.; Yi, N.-P.; Yan, L.-E., and Li, Y.-J., 2019. Numerical analysis for liquefaction deformation of low embankment on soft foundation based on water level changes in coastal highway. In: Gong, D.; Zhu, H., and Liu, R. (eds.), Selected Topics in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 94, pp. 321–326. Coconut Creek (Florida), ISSN 0749-0208. This paper mainly studies the water level change of coastal soft foundation by taking the soft foundation in the liquefaction zone of the Xiniujiao-Dafengjiang section of the coastal first-class highway in Guangxi, China as the research object. To this end, by arranging the saturated silt soft foundation of 6 1.5m inverted trapezoidal gravel wall low embankment structure in the vertical direction, the numerical simulation method was adopted to simulate its liquefaction deformation of the soft foundation problem under the traffic load in the working condition I (constant annual water level) and working condition II (temporary water level rise), and also judge its liquefaction potential, the development and dissipation of the pore water pressure, and the excess pore pressure ratio. Finally, the results show that under different water levels, the gravel-paving on embankment can effectively improve the liquefaction-resistant ability of the soft foundation and improve the uneven settlement of the original compacted fill embankment. [ABSTRACT FROM AUTHOR]

We investigate a solid state reaction between Ge and Ni–InGaAs on n+ In0.53Ga0.47As and its effects on the contact resistance of Ni-based contacts on InGaAs. This reaction was performed by isochronous annealing of Ge on Ni–InGaAs at temperatures ranging from 400 to 600 °C in N2 ambient. It was found that a regrown InGaAs layer rich in Ge was formed below the metal contact. Compared with Ni–InGaAs contact, more than 60% reduction in contact resistance on Si-implanted n-In0.53Ga0.47As was achieved after annealing at 600 °C. This contact structure was characterized by secondary ion mass spectroscopy, high resolution transmission electron microscopy, X-ray diffraction, and scanning electron microscopy. [ABSTRACT FROM AUTHOR]