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Weld defect recognition plays an important role in the manufacturing process of large-scale equipment. Traditional methods generally include several serial steps, such as image preprocessing, region segmentation, feature extraction, and type recognition. The results of each step have significant impact on the accuracy of the final defect identification. The convolutional neural network (CNN) has strong pattern recognition ability, which can overcome the above problem. However, there are two problems: one is that the pooling strategy has poor dynamic adaptability and the other is the insufficient feature selection ability. To overcome these problems, we propose a CNN-based weld defect recognition method, which includes an improved pooling strategy and an enhanced feature selection method. According to the characteristics of the weld defect image, an improved pooling strategy that considers the distribution of the pooling region and feature map is introduced. Additionally, in order to enhance the feature selection ability of the CNN, an enhanced feature selection method integrating the ReliefF algorithm with the CNN is proposed. A case study is presented for demonstrating the proposed techniques. The results show that the proposed method has higher accuracy than the traditional CNN method, and establish that the proposed CNN-based method is successfully applied for weld defect recognition.

Gas overruns and explosions often occur in coal mining. To deal with this problem, the spatial structure model of a new non-ventilation excavation system is constructed. Combined with the model, a simulation experiment is conducted and the variations in gas concentration in each area of the system with variations in the amount of gas emission, drainage, and nitrogen curtain outlet velocity are obtained. The effectiveness of the gas barrier by the combined action of the gas drainage and nitrogen curtain is verified. This study provides the experimental basis for solving the problem of gas overruns and explosions, and is of great significance for realizing safe, efficient, and rapid excavation.

For electrified transportation (eTransportation) systems, multi-phase motors can provide higher performance and reliability than three-phase ones, but also bring more challenges in their optimal design and control. In this article, a set of high reliable electric drive system based on dual three-phase permanent magnet synchronous motor (DTP PMSM) is developed for auxiliary systems in eTransportation field. A digital collaborative develop process is proposed with the support of multiple software tools. Design, manufacture, and bench testing stages of the DTP PMSM, the two-level six-phase inverter, and the control algorithm are efficiently incorporated. A prototype of the multi-phase electric drive system is fabricated and tested. Comparison of the simulation analysis and experimental results confirms the effectiveness of the collaborative develop progress. Control algorithms based on dual d-q model and vector space decomposition model are both verified and compared via the bench test. Operation mode switching from six-phase mode to three-phase mode is also realized with the prototype system, verifying its capability in fault-tolerant and potential in efficiency optimizing.

Materials based on graphene oxide (GO) have good adsorption capacities to various water contaminants in recent studies, owing to GO can provide more active sites than reduced graphene oxide. However, the inefficient preparation methods and tedious separation steps after adsorption limit their application in wastewater treatment. In this report, a facile method is proposed for the synthesis of a cetyltrimethylammonium bromide (CTAB)-GO composite via ionic interaction. The hydrophobicity of CTAB-GO composite is enhanced by the alkyl chains of CTAB, and thus, it can be readily separated from water-soluble impurities via low-speed centrifugation (3000 rpm for 3 min). The obtained CTAB-GO composite can efficiently remove the azo dye, Congo red from aqueous solutions, with an adsorption capacity as high as 2767 mg/g. Increasing the initial acidity of the solutions enhances the dye removal process. The adsorption kinetic studies reveal that the adsorption equilibrium achieves in ∼60 min, and the experimental data of the adsorption of Congo red fits well with the pseudo-second-order kinetic model and the Langmuir isotherm. Furthermore, the CTAB-GO composite presents good recyclability and the adsorption capacity is greater than 2000 mg/g even at the tenth cycle.

In order to effectively monitor the battery usage status of electric vehicle, this paper designs a high-precision voltage monitoring circuit applied to multi-series battery packs, which based on the 0.18μm, 40V high voltage BCD process. According to the characteristics of the voltage superposition and battery distinction in the series battery pack, this circuit uses the voltage conversion circuit with the matched negative feedback technology to achieve effective “scaling” of the battery's absolute high voltage to ground-based analog signals. Under the typical/slow/fast process corners, -40°C~85°C and1.5V~31.5V, the simulation results show that the monitoring error of single cell voltage is 1.92mV, and the relative error rate is less than 0.043%, showing out of the strong robustness.

A personalized thermal environment is an effective way to ensure a good thermal sensation for individuals. Since local thermal sensation and temperature distribution are affected by individual physiological differences, it is necessary to study the effects of physiological parameters. The purpose of this study was to investigate the effects of internal structures and tissue composition on head temperature distribution and thermal sensation. A new mathematical model based on fuzzy logic control was established, the internal structure and tissue composition of the head were obtained by magnetic resonance imaging (MRI), and the local thermal sensation (LTS) index was used to evaluate the thermal sensation. Based on the mathematical model and the real physiological data, the head temperature and local sensation changes under different parameters were investigated, and the sensitivity of thermal sensation relative to the differences in tissue thickness was analyzed. The results show that skin tissue had the highest influence ( C s k i n = 0.0180 ) on head temperature, followed by muscle tissue ( C m u s c l e = 0.0127 ), and the influence of adipose tissue ( C f a t = 0.0097 ) was the lowest. LTS was most sensitive to skin thickness variation, with an average sensitivity coefficient of 1.58, while the muscle tissue had an average sensitivity coefficient of 0.2, and the sensitivity coefficient of fat was relatively small, at a value of 0.04.

The most common yellow phosphor for wLEDs, Y3Al5O12:Ce3+ (YAG:Ce3+), suffers from a deficiency of red in its spectral content of light. In this paper, a new strategy is provided to tailor the Ce3+ spectral profile through surface-located dye molecules of ATTO-Rho101, which feature intense, broad absorption in the green-yellow spectral region of Ce3+ emission as well as bright red emission. Sphere-shaped and highly dispersed micrometer and nanometer-sized YAG:Ce3+ (micro/nano-YAG:Ce3+) was synthesized through a modified solvothermal method. Surface SiO2 coating and simultaneous dye embedding were performed on the solvothermally derived YAG:Ce3+, heat-treated micro-YAG:Ce3+ and commercial phosphors. Efficient radiative transfer/reabsorption from Ce3+ in the inner core of YAG to the dye molecules in the SiO2 outer shell, irrespective of the size of the phosphors, was demonstrated in the accumulated YAG:Ce3+@SiO2 + dye powder upon blue light excitation; this enhanced its red emission. Fluorescence microscopy was demonstrated to be a powerful tool to identify the reabsorption phenomenon of the powdered materials. Packaging the heat-treated micro-YAG:Ce3+@SiO2 + dye phosphors on blue LED chips yielded a warm wLED (Ra∼ 93), but an Ra of only ∼79 was obtained for the wLED with commercial YAG:Ce3+@(SiO2 + dye)5 due to the low concentration of phosphors dispersed in the epoxy resin and the resulting decreased reabsorption by dye molecules. Surface-protonated amine species were found to induce Ce3+→ Ce4+ oxidation upon activation by heating or photoirradiation and then quench the photoluminescence (PL) of micro-YAG:Ce3+ even after surface modification by SiO2, YAG or being embedded in an epoxy resin matrix. High calcination temperatures greatly improved the PL stability of micro-YAG:Ce3+ through the removal of surface-capped species. The dye in the silica matrix showed high stability against heating and irradiation due to the so-called "caging effects"; however, decreased photo-stability was found in commercial YAG:Ce3+@(SiO2 + dye)5 due to the incomplete and/or loose SiO2 layer grown during multiple surface modifications.

The Y3Si6N11:Ce3+ yellow phosphor shows a well-known ∼150 nm broad emission band, exhibiting a potential application in UV or blue based white LEDs. We report the observation of two Ce3+ emitting centers, the superposition of which forms the broad emission band. One center has a green emission band peaked at 539 nm (Ce1) with the first excitation band at 420 nm. The other has a red emission band peaked at 600 nm (Ce2) with the first excitation band at 485 nm. The two Ce3+ centers are assigned to the substitution for two Y sites in Y3Si6N11. It was found that the Ce2 emission intensity is continuously enhanced relative to that of Ce1 with an increasing Ce3+ concentration, thus leading to a redshift of the broadband. Meanwhile, a more notable fluorescence lifetime shortening of Ce1 compared to Ce2 with an increasing Ce3+ concentration was observed. These results suggest the occurrence of energy transfer from Ce1 to Ce2. The temperature-dependent luminescence intensity of Y3Si6N11:Ce3+ was also studied in the range of 93 to 473 K.

Recently, a new kind of distributed element superconducting resonators with granular aluminum (grAl) has been developed for circuit quantum electrodynamics. Given that lumped element resonators possess certain advantages over the distributed element ones, in this paper, we use a relatively simple micro-nanotechnology, without the etching process, to fabricate the designed lumped element superconducting grAl resonators. They are deposited on silicon substrates by DC magnetron sputtering of pure Al in an atmosphere of Ar and O2. By cryogenic microwave transmission measurements, at a temperature of 50 mK, we find that, compared with a usual Al resonator of the same size, such a device shows significantly strong nonlinearity and thus higher kinetic inductance. The noise features, quality factors, and temperature-dependence of the resonant frequencies have been investigated experimentally. It is believed that the lumped element superconducting resonators with high kinetic inductance demonstrated here could also be applied to superconducting quantum computation and photon counting in the future.

To utilize the lignite residues after humic acid extraction, experimental studies on pyrolysis of Xianfeng lignite residue (XLR) were conducted with a fixed-bed reactor under nitrogen atmosphere in the temperature range of 500–900 °C. The product gas yield and composition, and the properties of solid product were investigated and compared with those obtained from pyrolysis of Xianfeng lignite (XL). The results showed that the gas yield of dry-ash-free XLR was higher than that of XL and the content of CO in the product gas increased rapidly with increasing temperature. The surface area of the char from XLR pyrolysis increased as the pyrolysis temperature increased, which reached a high value of 612 m2/g at 900 °C compared to only 10 m2/g for the char obtained from XL pyrolysis. The porosity development in the former was due to the activation of carbon in the char matrix with Na-containing groups leading to the formation of micropores and mesopores in the solids, which could be potentially useful as adsorbents.

In this work, the metal–organic frameworks of ruthenium [Ru2II,III(BTC)2XxY1.5 − x] (BTC = 1,3,5-benzenetri-carboxylate, X, Y = Cl− or OH−, termed as Ru-MOFs) that are grown on montmorillonite (Mt) in a solvothermal reaction, and a type of composite materials (Ru-MOF_Mt) with open channels have been fabricated. Due to the high pore volume, the Ru-MOF particles are found to greatly enlarge the surface area of the hybrid material. To activate the metal centers in the Ru-MOF, the hybrids are annealed in a flow of H2 at mid-level temperatures (~ 300 °C). With this H2-annealing treatment the frameworks are found to be partly decomposed, and the coordinatively unsaturated sites (CUS) are produced. The annealed Ru-MOF_Mt is highly efficient in catalyzing reactions of benzene hydrogenation. The turn-over frequency (TOF) of benzene to hexane reaches 3478 h− 1. This catalyst is able to be reused at least five times without any de-activation demonstrating that the CUS are readily protected by the Mt layers.

A new method is developed to immobilize silver (Ag) nanocrystals (NCs) on carbon nanotubes (CNTs) by using the pre-coated MoS2 as sacrificial layers, and a type of composite materials consisting with CNTs, Ag NCs and MoS2 have been prepared. In this method the ultral-thin layers of MoS2 are coaxially pre-coated on the CNTs to prepare the hybrid of CNTs-MoS2. The CNTs-MoS2 is used as substrates to immobilize Ag NCs in a hydrothermal solution. During the hydrothermal reaction the MoS2 is oxidized by [Ag(NH3)2]+, and parts of the MoS2 layers are removed in the form of (NH4)2MoO4. The Ag NCs are found to be uniformly dispersed on the CNTs-MoS2. The fabricated composites (CNTs-MoS2–Ag) exhibit excellent catalytic performances in the antibacterial tests under illumination by visible lights. The antibacterial performance is contributed by the ultra-small Ag NCs and the brilliant photo-absorption afforded by the synergistic effects between the CNTs-MoS2 and Ag NCs.

Building 3D tunnel model is one of the important work in underground mining management, the methods to build 3D tunnel model by secondary development of commercial software or using OpenGL are not convenient and efficient. After analyzing the structure of DXF file, a method that building 3D tunnel model based on DXF file is proposed. On the basis of designing the tunnel section type and parameters, the modeling process is given in details. The result shows the method has a good efficiency and more convenient to realize.

The induced airflow velocity level and the mechanical efficiency are the significant issues for the surface DBD flow control application. In this paper, the effects of optical characteristics, electrical performances and mechanical properties of surface DBD with composite dielectric glass/PI film are investigated. The current, discharge plasma morphology, electrical power consumption, and induced airflow velocity are analyzed at applied voltage 17-23 kV with working frequency 9.15 kHz. The experiment results indicate that with the addition of PI film, the discharge just occurs near the exposed electrode and is suppressed obviously in the negative half cycle of current. Though the induced airflow velocity decreases slightly about 0.1-0.2 m/s at each voltage level, the mechanical efficiency substantially improves. The maximum mechanical efficiency increases by 25.12% under the 23 kV.The induced airflow velocity level and the mechanical efficiency are the significant issues for the surface DBD flow control application. In this paper, the effects of optical characteristics, electrical performances and mechanical properties of surface DBD with composite dielectric glass/PI film are investigated. The current, discharge plasma morphology, electrical power consumption, and induced airflow velocity are analyzed at applied voltage 17-23 kV with working frequency 9.15 kHz. The experiment results indicate that with the addition of PI film, the discharge just occurs near the exposed electrode and is suppressed obviously in the negative half cycle of current. Though the induced airflow velocity decreases slightly about 0.1-0.2 m/s at each voltage level, the mechanical efficiency substantially improves. The maximum mechanical efficiency increases by 25.12% under the 23 kV.

The Neoproterozoic Zhoutan Group, located at the conjunction area between the Yangtze and the Cathaysia Blocks, preserves an important record of the Neoproterozoic sedimentary system of the South China Block. However, its accurate depositional age, provenance, and tectonic affinity remain poorly studied. Here, we report new LA-ICP-MS detrital zircon U–Pb age data of four meta-sedimentary samples from the Zhoutan Group in the Nancheng area for complemental decipherment of its sedimentary and tectonic histories. Concordant detrital zircon ages reveal proportions of 54% latest Mesoproterozoic to early Neoproterozoic (ca. 1050–820 Ma), 24% early Paleoproterozoic (ca. 2500–2150 Ma), and 22% late Paleoproterozoic to early Mesoproterozoic (ca. 2000–1500 Ma) populations. Youngest detrital zircon age clusters exhibit a consistent weighted mean age of ca. 827 Ma, suggesting the maximum Tonian depositional age of the Zhoutan Group. Provenance interpretations reveal that the detritus of investigated samples were mainly sourced from the proximal Jiangnan Orogen with some additionally derived from the Cathaysia Block, the interior Yangtze Block, and/or extraneous terranes. In addition, the appearance of some later early Palaeozoic-aged (ca. 437 Ma) metamorphic rims and grains suggest that the Zhoutan Group has locally experienced an intense metamorphism during the early Palaeozoic (Silurian) time, which has been consistently recorded by the Neoproterozoic meta-strata in the Cathaysia Block. These new data, together with those from previous studies, indicate that the Zhoutan Group belongs to the early Neoproterozoic sedimentary successions between the Yangtze and the Cathaysia Blocks. Subsequently, it might be thrusted onto the present side of the Cathaysia Block during later tectonic processes and was affected by locally metamorphism during the Silurian time. Thus, such observations suggest that the potential border between the Yangtze and the Cathaysia Blocks should be to the north of the current position of the Zhoutan Group. Refereed/Peer-reviewed