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Weakly disseminated sulphide mineralization is present in the outcrops of several mafic–ultramafic intrusions in the Beishan region of the Central Asian Orogenic Belt in western China, but the pote...

This article proposes a new method for semiautomatically generating the image Mask required for training Mask R-CNN. Since manual labeling is very time-consuming and laborious to obtain the image mask, we propose a very simple and fast method based on graph cut to obtain image Mask method, which uses graph cut-based image segmentation to output pixel-level segmentation results and obtain Mask of the input image through image transform, and then, the Mask R-CNN-based surface defect detection method is implemented, which includes three different branches, namely, the boundary box regression and positioning branch, the boundary box classification branch, and the segmentation branch, to realize the function of locating, classifying, and segmenting defects at the same time. The experimental results confirm the effectiveness of our proposed method; under the premise of ensuring the detection accuracy of the Mask R-CNN method, the Mask required for training Mask R-CNN can be quickly and simply obtained.

Clearance of endogenous glutathione (GSH) to cytotoxic hydroxyl radicals (·OH) and insufficient cellular hydrogen peroxide (H2O2) limited the efficacy of chemodynamic therapy (CDT) to tumor. Herein...

This article proposes a novel solder joint recognition method based on the state-of-the-art Mask Region-convolutional neural network (R-CNN) deep learning method. Traditional classification methods, such as neural networks and statistical methods, can only classify defect type, and the template-matching method can only match the position of the object. Based on Mask R-CNN, our proposed approach can classify, position, and segment the solder joint defect at the same time. To train our Mask R-CNN-based detection method, the transfer learning method uses the ResNet-101, which is initialized and trained on the Microsoft COCO data set. Through experimentation, our proposed method obtained better results than the traditional classification method in solder joint recognition, and it can achieve very high classification accuracy with more than 95% mean of average precision (mAP) for segmentation. The proposed method can classify and identify the position and segment of the solder joint defect simultaneously with very high recognition accuracy.

In this work, a new core-shell structure of antiferroelectric ceramic powder (Pb0.97La0.02Zr0.85Sn0.12Ti0.03O3-PLZST) coated with linear dielectric (Al2O3) has been successfully prepared to realize high energy density through tape-casting process. According to the experimental results of electron microscope, the sol-gel derived Al2O3 layer was uniformly coated on the PLZST particles and the Al2O3 layer can be taken as the buffer layer to effectively refine the grain growth as well. Therefore, the modified PLZST particles were fine and uniform compared with the pure PLZST. It was found that the buffer layer could undertake higher electric field and the electric field applied to PLZST particles was weakened based on finite element analysis, which can avoid the premature breakdown of PLZST. And the actual measured breakdown strength was significantly enhanced from 22.2 kV/mm to 35.5 kV/mm. Correspondingly, an extremely high recoverable energy storage density of 5.3 J/cm3 was obtained for PLZST with 0.5%wt Al2O3, an 204% enhancement over the pure PLZST ceramics (2.6 J/cm3), and the corresponding efficiency was up to 88.3%. In addition, impedance spectroscopy measurement was carried out to further confirm the better insulation of the ceramic with Al2O3 buffer.

The fabrication of platinum (Pt)-based electrocatalysts with high electrochemical durability is a key prerequisite for the practical application of proton exchange membrane fuel cells (PEMFCs). In this work, we present an effective and scalable strategy to strongly stabilize Pt nanoparticles at a Ta-based (Ta2O5–TaC) binary junction formed by a controllable carbothermal phase conversion process, affording stable Pt–Ta2O5–TaC triple interfaces for durable catalysis of the oxygen reduction reaction (ORR). Our strategy utilizes a robust corrosion-resistant support for Pt nanoparticles involving a hollow-structured Ta2O5–TaC composite anchored on a thin carbon skeleton; the presence of the composite inhibits corrosion of the carbon support. The resulting hybrid support overcomes the drawbacks commonly associated with metal oxides and has a large specific surface area and high electrical conductivity owing to the presence of TaC and the carbon skeleton. X-ray absorption near edge structure analysis indicates the presence of strong interactions between Pt and Ta2O5–TaC that induce a surface electron delocalization of Pt and ensure the strong anchoring of Pt nanoparticles. When used as a catalyst for the ORR, the Ta2O5–TaC/C supported Pt electrocatalyst has high mass (0.297 A mgPt−1) and specific (0.424 mA cm−2) activities (respectively 3.7 and 3.2-times those of commercial Pt/C) at 0.9 V. Furthermore, the electrocatalyst exhibits an outstanding electrochemical durability without any obvious degradation after 10 000 potential cycles in 0.1 M HClO4 solution, significantly outperforming commercial Pt/C which suffers 107 mV loss of half-wave potential. Our synthesis strategy offers a new avenue for developing highly durable Pt-based electrocatalysts with high activity which should have applications in practical PEMFCs.

Alumina (Al2O3) thin films derived from a sol-gel wet chemistry process were used to prepare capacitors with a simple MIM structure of Al/Al2O3/Pt. Driven by the external applied electric field, the phenomenon of anodic oxidation has been observed and confirmed at the Al/Al2O3 interface，resulting in the formation of a new alumina blocking layer (BL). Importantly, similar to the product of anodic oxidation of aluminum in liquid electrolytes, the blocking layer here exhibited excellent electrical characteristic and voltage-dependent growth mode as well, which endowed the capacitor with less defective electrode/film structure and self-enhanced electrical performance under the application of external voltage. Specifically, an ∼50% enhancement of the maximum working voltage and better capacitance characteristics of the thin film capacitor can be achieved. With the impedance and finite element analyses, the electrical characteristic of the BL and its corresponding effect on the alumina capacitor were explored in depth.

In-situ formation of emulsions has been observed in a large amount of chemical flooding pilots, and their effect on oil recovery is of great interest to petroleum engineers and researchers. In this study, microfluidic and transparent sand pack models were used to investigate mechanisms of emulsion propagation and plugging in both pore and macro scales. A microfluidic chip consisting of high- and low-permeability areas was fabricated to represent a heterogeneous area. Another chip was created with the same throat width but enlarged pore sizes (1.5 times larger) and reduced throat lengths. Two microscopic displacement experiments were conducted to compare the effect of pore structure on residual oil displacement after surfactant/polymer (SP) flooding by injecting the same emulsion slug. Meanwhile, the macroscopic flow path of the displacing fluid in the emulsion flooding was investigated using a relatively homogeneous transparent 2D sand pack. The emulsion plugging was proved to be a complicated process, and it could be strongly affected by pore throat structures. Fluid division and high oil recovery could only be achieved during the emulsion flooding in the condition with properly matched sizes of emulsion droplets and pore throats. For a relatively homogeneous 2D sand pack model, oil bank formation and enlarged sweep volume were observed in the emulsion flooding even though it was conducted after SP flooding. As suggested by results of this study, the in-situ formation of emulsion might significantly contribute to the oil recovery in reservoirs with tortuous pore structures, while making little difference in those with large pore throat channels that emulsion couldn’t be trapped in.

A Ni and MoxC hybrid (Ni-MoxC) supported on N-doped reduced graphene oxide (N-rGO) electrocatalyst with high hydrogen evolution reaction (HER) activity was prepared by ultrasonication and lyophilization. Notably, benefiting from the synergistic effect between Ni and MoxC nanoparticles, the optimized electrocatalyst displayed excellent catalytic activity with low overpotentials of 183 mV and 216 mV for the HER at the current density 10 mA cm−2 in 1.0 M KOH and 0.5 M H2SO4 solution. The stability of the electrocatalyst could be well maintained for 24 h. These results indicate that the method to prepare hybrid (Ni-MoxC) is a simple way to produce cost-effective and high-efficient molybdenum carbide for hydrogen evolution.

A novel core-shell structured Pb0.91La0.06(Zr0.552Sn0.368Ti0.08)O3@PbO–B2O3-SiO2-Al2O3-ZnO-MnO2 (PLZST@PBSAZM) antiferroelectric particles were successfully fabricated via sol-gel method. As expected, the sintering temperature was notably reduced from 1250 oC to 1100 oC with the increasing glass contents. More importantly, the breakdown strengths of PLZST@PBSAZM ceramics were significantly increased from 252 kV/cm to 402 kV/cm. As a result, the energy density was up to 7.4 J/cm3 with 1 wt.% of coating glass content, a 55.3% enhancement over the pure PLZST (4.7 J/cm3). Furthermore, the simulations of electric field distribution provided a powerful evidence that the enhancement of the breakdown strength was induced by the core-shell structure, since the glass coating layer could not only undertake the most of electric field, but also impede the grain growth to achieve the smaller grains, which led to the reduction of electric field intensity on the grain cores.

This study investigates the very-high-cycle fatigue (VHCF) behavior at elevated temperature (650 °C) of the Inconel 718 alloy fabricated by selective laser melting (SLM). The results are compared with those of the wrought alloy. Large columnar grain with a cellular structure in the grain interior and Laves/δ phases precipitated along the grain boundaries were exhibited in the SLM alloy, while fine equiaxed grains were present in the wrought alloy. The elevated temperature had a minor effect on the fatigue resistance in the regime below 108 cycles for the SLM alloy but significantly reduced the fatigue strength in the VHCF regime above 108 cycles. Both the SLM and wrought specimens exhibited similar fatigue resistance in the fatigue life regime of fewer than 107–108 cycles at elevated temperature, and the surface initiation mechanism was dominant in both alloys. In a VHCF regime above 107–108 cycles at elevated temperature, the wrought material exhibited slightly better fatigue resistance than the SLM alloy. All fatigue cracks are initiated from the internal defects or the microstructure discontinuities. The precipitation of Laves and δ phases is examined after fatigue tests at high temperatures, and the effect of microstructure on the formation and the propagation of the microstructural small cracks is also discussed.

Korea’s automobile industry has not developed for a long time, but it has achieved a leading position in the world, and also occupied part of the Chinese market. What causes this result is worth studying. Based on the big data, this paper uses the result equation model to analyze the development of Korean automobile industry in China

CNC machine tool plays a vital role in intelligent manufacturing, but up to now, CNC controller, which works as the “brain” of the machine tool, is just a loyal executor of machining command without intelligence. This paper is aimed to improve the intelligence of CNC controller from the aspect of machining process planning, which has a great effect on product quality and production efficiency. A STEP-compliant data model is adopted. Compared to previous STEP-NC controller, this paper presents a new paradigm to integrate the ability of autonomous process planning into CNC controller based on cloud knowledge base. A hierarchical and modular architecture is designed to obtain machining process planning from cloud knowledge base timely and to conduct the machining implementation on shop floor. Furthermore, efficient and matching operation mechanism is researched. It offers a proposal to use cloud knowledge to implement intelligent manufacturing. Finally, a case study is demonstrated to verify the feasibility of this intelligent CNC controller.

Nano-Au self-producing process was investigated to improve the dielectric properties of amorphous Al2O3 thin films via controlling the heat-treatment temperature. The results of high-resolution transmission electron microscopy (HTEM) showed that the nano-Au particles were uniformly dispersed in the amorphous Al2O3 matrix. More importantly, nano-Au particles could supply more space polarization charges and the dielectric constant of the nanocomposite thin film was enhanced from 8.2 to 32.2. As a result, the ultimate energy density was up to 13.3 J/cm3 with 2 mol% doping content, which is increased by about 137.5% compared to the pure counterpart. Furthermore, the thermally stimulated depolarization current (TSDC) analysis provided a powerful evidence to testify that the enhancement of the dielectric constant was originated from the trap charge polarization after the nano-Au doping. The finite element simulation results showed that the more space charges were generated around the nano-Au particles, which is more intuitive to understand the reason for the increase of the dielectric constant.

The through-thickness inhomogeneity of environmentally assisted cracking (EAC) for AA5083-H128 thick plate is investigated based on sensitization treatments, microstructure characterization, slow strain rate tests (SSRT) and J-based fracture tests. More continuous Mg-rich precipitates with a higher Mg concentration are identified along the grain boundaries of sensitized specimens excised from near the top of the plate than those of specimens excised from the middle of the plate. The larger amount and grain boundary coverage of Mg-rich precipitates present after sensitization for samples excised from the top of the plate was consistent with both mechanical tests (i.e. SSRT, J-based fracture) that showed greater EAC susceptibility than samples excised from the middle of the plate. In the J-based fracture tests, sensitized specimens tested in the S-T orientation exhibited greater EAC susceptibility than L-T specimens. In the L-T tests, more grain boundary delamination, likely caused by hydrogen embrittlement from the hydrogen evolution associated with the corrosion of the Mg-rich phases, was exhibited on the fracture surfaces for sensitized specimens removed from the top of the plate compared to the middle. Despite this embrittlement, this grain boundary delamination contributed to the greater crack growth resistance exhibited by the sensitized L-T samples due to delamination toughening.

An original design of sandwich-structured SrTiO3 (STO) nanocomposite thick films has been achieved via a sol–gel based coating process. In that process, a pure STO amorphous film is set as the central layer and the STO composite films containing nanoparticle fillers and amorphous matrices are employed as two outer layers. It is revealed that the central amorphous layer with optimal thickness can permeate within the composite layer and effectively eliminate the interfacial structural defects (voids and cracks), giving rise to an increased dielectric constant. Additionally, the finite element simulation results show that the design of a sandwich structure is conducive to enhancing the Eb value of the nanocomposite films. It is because the middle amorphous layer could not only alleviate the high local electric field concentration caused by interface voids and cracks, but also lower the electric field in the outer composite layer to protect the sandwich-structured films from being broken down early. As a result, the sandwich-structured films reach the largest energy density of 10 J cm−3, which increases by 177% compared to the films without interface modulation (3.6 J cm−3).

Taking Al as top electrode, a repairing layer with ultrahigh dielectric strength and resistivity was generated at the interface between sol-gel Al2O3 films and electrodes under the applied electric field. This repairing layer effectively restored the defects on the film surface and improved the dielectric strength. More importantly, it was found that adding ZrO2 nanoparticle into the matrix film could further enhance the dielectric strength, since the ZrO2 nanoparticle is conductive to forming the interfacial repairing layer. The analysis of ac conduction properties showed that the introduction of nano-ZrO2 resulted in a lower potential barrier and a longer hopping distance for ionic migration. In addition, the simulation result indicated that nano-ZrO2 addition induced a local region of high electric field that accelerated ionic migration. As a result of the two factors, the nanocomposite structure of Al2O3/nano-ZrO2 is capable to provide more ions for the formation of interfacial repairing layer. With the stronger repairing behavior, Al2O3/nano-ZrO2 composite films exhibited significantly enhanced breakdown strength of ~ 576 MV/m and energy density of 14.7 J/cm3, in contrast with 385 MV/m and 5.9 J/cm3 for pure Al2O3 films with Al electrodes.

Process of self-growth nanocrystalline structure was explored to improve the dielectric properties of amorphous Sr0.925Bi0.05TiO3 (SBT) thin films through controlling the annealing temperature. The crystallinity of the material was 15% when annealed at 550 °C, and the resulting nanocrystalline particles were 14 nm in size as determined by XRD analysis. Therefore, the proposed process could produce a novel film of an amorphous matrix coating nanocrystalline particles. Finite element analysis results showed that the applied electric field was focused primarily in the amorphous matrix, which could effectively decrease the probability of low voltage breakdown of the nanocrystalline particles. Simultaneously, the nanocrystalline particles supplied more polarization charges, which helped to improve the dielectric constant of the inorganic composite. Combining the merits of amorphous and crystalline phases, the ultimate energy storage density of the modified sample was as high as 21.2 J/cm3, which represents an improvement of 5.1 J/cm3 compared with that of pure amorphous SBT thin film.

A sol-gel based coating technology was utilized to improve the dielectric properties of SrTiO3 (STO) thick films based on crystalline@amorphous core-shell nanostructure. In this route, poly(vinyl pyrrolidone) (PVP) was used as the surface modification agent to optimize the dispersibility of nanoparticles, which played an important role in promoting the dielectric homogeneity in the nanocomposite films. The crystalline@amorphous structure could achieve both the enhanced dielectric constant and high breakdown strength because the external amorphous STO matrix shells were capable of undertaking higher applied field while the internal STO nano-crystalline cores supplied more polarization charges. Compared with the amorphous matrix, the dielectric constant of the modified film could be increased from 15 to 46 under the precondition of maintaining the high breakdown strength (170 MV/m). Consequently, the calculated energy density is 5.9 J/cm3. Furthermore, based on the electric field simulation result, it can be concluded that interface blocking effect created by the amorphous layers and reduced electric field intensification by PVP modification led to the enhancement in breakdown strength.

The effects of sensitization (175 °C for 100 h) and microstructure anisotropy on corrosion and environmental cracking of AA5083-H128 have been studied using immersion tests, electrochemical experiments and slow strain rate tests (SSRT). Pitting corrosion attack is observed for as-received (AR) and sensitized polished surfaces after immersion in 0.6 M NaCl solution at open circuit potential and is strongly dependent on the amount and distribution of intermetallic particles, including Mg-rich phases resulting from sensitization, as well as pre-existing anodic Mg-rich and cathodic (Mn, Fe)-rich particles. Anodic potentiodynamic polarization experiments indicate that sensitization increases the activity of the surface with a negative shift in corrosion potential and an increase in anodic reaction kinetics. SSRT tests show that samples orientated along the short transverse (S) direction exhibit the largest susceptibility to intergranular stress corrosion cracking (IGSCC), followed by samples with transverse (T) orientation, and then samples with longitudinal (L) orientation. Serrated stress–strain response and flow instability, referred to as the Portevin-Le Chatelier (PLC) effect, is exhibited in SSRT curves, and is more pronounced in L-orientated samples compared to T- and S-oriented samples. The effects of microstructure anisotropy and sensitization on the environmental cracking and the PLC effect are discussed.

A nitrogen-doped porous carbon materials (CPNs) with supported Co nanoparticles (Co@CPNs) with lamellar structure, high surface area and excellent magnetic properties was synthesized successfully by one-pot method. The Co@CPNs exhibited an excellent catalytic activity with 99% conversion and selectivity for hydrogenation of furfural (FAL) to furfuryl alcohol (FOL) under the pressure of H2. In addition, the Co@CPNs were further investigated in the kinetic study and selective hydrogenation of the other α, β unsaturated carbonyl compounds. The study of the Co@CPNs indicated that it was suitable for selective hydrogenation of the α, β unsaturated carbonyl compounds in the industry.

Nowadays, machining task becomes more and more complex and customized product needs small quantity manufacturing, which come up with higher demands for CNC machine tools to realize smart manufacturing. However, current process planning is generally made by process planners depending on their professional knowledge and experience rather than CNC machine tools. Several knowledge bases are developed to make CNC machine tools more intelligent. In process planning, a proper methodology for capturing knowledge is essential for constructing a knowledge base to support process planning decision making. Therefore, this research presents a knowledge generation mechanism to generate machining solutions taking advantages of Map/Reduce framework to handle large-scale data. Knowledge unit is defined, which consists of generalized feature and operation to store process knowledge. Workingstep is as the instantiation of knowledge unit, which is stored in database as the data foundation for query and reasoning. According to the top-down idea of hierarchical clustering algorithm, all workingsteps are clustered to get several similar workingsteps. Then query engine tries to inquiry workingsteps which contain same generalized features to the task, if there is no workingstep fulfilling requirements, reasoning engine is dealing with this situation to generate new workingsteps. After that, a machining solution is generated according to reasoning rules for working sequencing. Finally, a test example is given to validate the proposed approach and result is presented to demonstrate and verify the generation mechanism.

Proton gradient reactions are common, but those with inverse proton gradients are rare. Inspired by the phenomenon that stomach can release acid with microenvironment changes, an inverse proton gradient process along with a ring-closing of the precursors of oxazolidine molecular switches (i.e., ROF+X−s) was achieved within specific microenvironments both in solution and on solid substrate. Nucleophilicity and concentration of solution were found playing important roles in this process. Furthermore, benefits from this ring-closing process arose from inverse proton gradient, a potential application of ROF+X−s replacing their akalization products—ring-closed forms (RCFs) of oxazolidines in water-jet rewritable paper (WJRP) was developed. Influence of dissolving solvent and drying temperature on hydrochromic performances of ROF+X− based WJRP were inspected and compared to its corresponding RCF based WJRP. Results indicate that the former outperforms the latter in color depth, coloration speed and retention time. The water-jet prints on ROF+X− based WJRP exert excellent legibility, resolution, uniformity, and repeatability. This research achievement will not only promote the industrialization of oxazolidines derivatives based WJRP by greatly reducing production costs from a perspective of synthetic industrialization, but may also provide a reference for better understanding of similar microenvironment-induced phenomena of inverse proton gradient in complex biosystems.

The breakdown strength and energy storage performance of SrTiO3 thin film were substantially improved by means of two different modifications on the micro and macro levels. On the micro level, the cyclic cooling–heating process caused the repeated displacement of interstitial atoms, resulting in the interstitial atoms returning to the original defect location and the restoration of internal defects. On the macro level, a blocking layer with high resistivity was generated between the Al top electrode and the SrTiO3 thin film, which could effectively prevent the charge carriers at the interface. After micro and macro modification, electrode damage caused by the edge effect was effectively restrained and the space charge limited conductance (SCLC) mechanism was almost eliminated. Thermally stimulated depolarization current (TSDC) spectra provided powerful evidence to testify that the number of traps sharply decreased after cyclic cooling–heating. As a result of the defect restoration as well as the interfacial blocking effect, the leakage current was decreased by one order magnitude and the breakdown strength was enhanced from 142.8 MV m−1 to 607.1 MV m−1. More importantly, the ultimate energy density was up to 30.31 J cm−3, which is 1132% greater than the sample without micro and macro modification.

Developing highly active electrocatalysts with low cost and high efficiency for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential for water splitting. In this work, we for the first time report a high-efficiency electrocatalyst cobalt telluride encapsulated in nitrogen-doped carbon nanotube frameworks (CoTe2@NCNTFs) derived from metal–organic framework ZIF-67, which was synthesized via a straightforward telluride process under a hydrogen atmosphere. Notably, benefiting from the hollow polyhedron carbon nanostructure with large surface area, high conductivity, fast electron transport, and open channels for effective gas release, the as-synthesized electrocatalysts exhibit remarkable catalytic activity, with overpotentials of 330 mV and 208 mV toward the OER and HER at a current density of 10 mA cm−2 in 1.0 M KOH solution, respectively. Moreover, when CoTe2@NCNTFs was fabricated as an alkaline electrolyzer in basic solution, overall water splitting was achieved with high efficiency, which was comparable to the integrated performance of the commercial IrO2 and Pt/C catalyst couple. Our work provides a way for developing efficient noble-metal-free catalysts via rational surface engineering.

High-precision, non-enzymatic electrochemical detection of glucose is of vital importance for the diagnosis and treatment of diabetes mellitus. To meet this requirement, a facile and effective strategy for creating glucose-sensitive detective materials with high sensitivity and selectivity is demonstrated via the synthesis of Ni nanoparticles self-supported on N-doped carbon (Ni/NC) by direct pyrolysis of cross-linked nickel polyphthalocyanine (NiPPc) for non-enzymatic glucose detection. Owing to the extended electronic structure of the N-doped carbon supports and the considerable improvement in charge/mass transport, the resultant Ni/NC sample exhibits excellent activity and long-term reusability in non-enzymatic glucose detection, with a sensitivity of 660.3 μA mM−1 cm−2 and a rather low detection limit of 0.12 μM, along with a wide linear range of 2 μM to 4.658 mM. The facile and promising synthetic strategy of Ni-based sensors for non-enzymatic glucose detection may offer an advanced alternative to noble metal and enzymatic sensors for the diagnosis of diabetes mellitus, and may promote the development of such materials in medical technology.

Herein, a novel aluminium/amorphous aluminium oxide (Al/AmAO) multilayer film was fabricated, which exhibited enormous potential application in the energy storage field due to its low leakage current, high operating voltage and high energy density. Specifically, (a) its leakage current density was remarkably suppressed (stabilized at ∼5.4 × 10−5 A cm−2); (b) its operating voltage was drastically enhanced to 591 MV m−1; and (c) its energy density was as high as 13.9 J cm−3. The amorphous aluminium oxide thin film was prepared via a facile sol–gel and spin-coating method. Its outstanding electric properties were attributed to the interfacial evolution of the newly-formed dense aluminium oxide (NAO) freshly developed at the Al/AmAO interface during the application of a positive voltage. Furthermore, the electric characteristics and growth mechanism of NAO were investigated. The results revealed that NAO, possessing an ultrahigh resistivity of ∼9.4 × 1012 Ω cm, endowed Al/AmAO with excellent energy storage density and limited leakage current. The NAO growth model, which originates from the transformation of the amorphous aluminium oxide and chemical reaction of the aluminium electrode, was proposed to deeply understand interfacial evolution behaviour. The novel and simple multilayer film, which achieved excellent properties via interfacial evolution rather than the traditional methods for improving the dielectric properties of dielectric materials, offers a convenient and effective approach for the design of high-performance dielectric capacitors.

Exploring the sensitive and reliable methods for the determination of hydrogen peroxide (H2O2) is a crucial issue for the health and environmental challenges. Herein, we demonstrate a facile, but rational and effective solvothermal approach to the synthesis of hierarchical NiO mesoporous nanospheres (NiO-MNS) as an effective non-enzymatic sensor towards the H2O2 detection. Owing to the intercalation and stabilization effect of polyethylene glycol for the Ni(OH)2 intermediate, the NiO mesoporous nanosphere (NiO-MNS) product is consistent with the low-dimensional nanostructured NiO blocks with large surface area and plentiful mesopores after the calcination treatment. The obtained NiO-MNS sensor presents superior electrochemical performance with a high sensitivity (236.7 μA mM−1 cm−2) and low limit of detection (0.62 μM), as well as the good selectivity and reliability for the further application of H2O2 detection. In addition, the unraveling mechanism of the mesopores formation derived from the in situ measurements also offers the valuable guidance for the future design of porous materials for electrochemical devices and other applications.

We have for the first time experimentally demonstrated a high repetition-rate picosecond fiber laser source at 2 $\mu \text{m}$ by a spectrally masked phase modulation technique, where a phase modulator driven by a sinusoidal RF signal and a fiber Bragg grating are used to convert the output of a 2- $\mu \text{m}$ continuous-wave single-longitudinal-mode diode to a picosecond pulse train. The repetition-rate of this laser source can be continuously and flexibly tuned from 1 to 6 GHz by simply changing the RF signal. We achieved a shortest pulse width of ~60 ps and a high SNR of >75 dB at an operating frequency of 6 GHz. The simplicity and robustness of such a picosecond laser as well as the ability to synchronize with an external trigger make it a highly useful source for 2- $\mu \text{m}$ high speed optical data processing, communications, and metrology.

Self-repairing behavior of SrTiO 3 film capacitor was explored to improve the energy density. With Au and Al being deposited on SrTiO 3 thin films as top electrode, the breakdown processes were investigated by a real-time optical microscope system. A high electric field of the electrode edge attributed to edge effect provided the “trigger factor” for the self-repairing behavior. Absorbed water not only provided “mobile phase” for self-repairing process which significantly enhanced breakdown strength but also, and equally important, it supplied additional polarization charges to raise dielectric constant. As a result of the concurrent increase in E b and e r , a higher energy density of 15.7 J/cm 3 is achieved. A leakage current platform was observed in the self-repairing process and the thickness of a new layer Al 2 O 3 film generated from self-repairing process was estimated according to Ohm's law and breakdown strength. Using relative humidity dependence of breakdown voltage, the maximum breakdown field was explored to realize the optimum self-repairing capability.

Thermally stimulated depolarization current (TSDC) was investigated on amorphous SrTiO3 film to study the internal polarization mechanism. Three TSDC peaks were observed around 240 K, 270 K and 320 K, respectively. By comparing the experiment results with the theoretical characteristics of three polarization mechanisms, the first peak was assigned to dipole polarization and the second peak was consistent with ionic polarization. The origin of the third peak was ascribed to the trap charge depolarization, since it exhibited a typical linear relation between poling field and square of peak temperatures. In addition, the second peak vanished after the sample had been treated by heating treatment to remove the absorbed water, indicating that the second peak arose from the absorbed water. For the absorbed water, the activation energy of ionic polarization activation energy and ionic conductance are approximately equal, which suggests that ionic polarization charge could turn to be ionic conductance with increasing field.

This paper presents a method of fracture and vug characterization and automatic classification of rock type in a naturally fractured vuggy carbonate reservoir using X-ray computed tomography (CT). First, using image processing technologies such as image segmentation, morphological processing and skeleton extraction, the fractures and vugs in the CT images of core plugs were characterized, and then, the characteristic parameters of the fractures and vugs were calculated. Then, a support vector machine (SVM) was utilized for automatic classification of the fractures and vugs. The shape and the eccentricity of fractures and vugs as the SVM training eigenvectors can effectively distinguish fractures from vugs with high classification confidence. Finally, with the characteristic parameters of fractures and vugs calculated from the CT images of core plugs, a new defined function of the carbonate rock index (CRI) was proposed, which can quantitatively classify the carbonate rock into three different types: matrix, fractured and vuggy. After analysis of more than 200 core plugs from the Y reservoir in the Middle East, the CRI values for matrix, vuggy and fractured carbonate rock were given and are 0 10, respectively. A high CRI value indicates a high fracture density, and a small CRI value indicates that the carbonate rock is mainly matrix without fractures and vugs. For the vuggy carbonate core plug, the CRI value is in between those of fractured core plugs and matrix core plugs. Therefore, the value of CRI can quantitatively evaluate the heterogeneity of carbonate rock due to fractures and vugs. The field application of this method demonstrated that this new method can effectively characterize fractures and vugs and quantitatively classify the rock type of the naturally fractured vuggy carbonate reservoir.

The development of robust, active and nonprecious electrocatalysts for hydrogen evolution reaction is quite urgent but still challenging. Here MoS2 QDs@Graphene is prepared via a facile lyophilization method, which leads to a better dispersion of MoS2 QDs on the graphene and optimizes the electronic mobility between the MoS2 layers. Impressively, the electrocatalyst MoS2 QDs@Graphene demonstrates the remarkable activity for HER in 0.5 M H2SO4 solution, with a current density of 10 mA cm(-2) at a low overpotential of 140 mV and strong stability in acid condition. The achieved excellent performance is attributed to its morphology with large amount of active sites fabricated by the lyophilization method. This new method opens new pathway for the fabrication of non-precious metal electrocatalysts achieving high activity. (C) 2017 Elsevier B.V. All rights reserved.

Comparing the frequency spectrums of the measured signals from both outer surface-mounted electrostatic sensor and inner flush-mounted electrostatic sensor, it is found that the transferred charge signal which used to be ignored appears primarily in the mean value of the measured signal. Furthermore the signal frequency spectrum of inner flush-mounted electrostatic sensor contains a critical frequency for decoupling induced charge signal and transferred charge signal. Then harmonic wavelet transform is proposed to decompose the measured signal. As a result, the induced charge signals from the upstream and downstream electrodes have higher similarity than the directly measured signals. Thus the mean cross-correlation coefficient increases from 0.61 to 0.78, which contributes to the cross-correlation velocity. In addition, the RMS value of the transferred charge signals increases linearly with the increasing of both the particle mass flow rate and the superficial air velocity, which is an effective prediction method for particle mass flow rate.

Here, we synthesized a Mo2C-Ni-modified nitrogen-doped carbon nanofiber (Mo2C-Ni@N-CNF) material by a Te nanowire template-directed hydrothermal and carbonization process. It was found that the addition of Ni nanoparticles could improve the activity of the hydrogen evolution reaction (HER) by a synergistic effect within the Mo2C-modified N-CNFs. As we expected, the as-synthesized Mo2C-Ni@N-CNF with a Ni/Mo ratio of 0.046 was nearly the most efficient non-noble-metal catalyst for the HER with acidic media at present, and has a low overpotential and a small Tafel slope of 65 mV vs. RHE (at a current density of 10 mA cm−2) and 72 mV dec−1 respectively, as well as satisfactory stability. Besides, it also has relatively good HER performance in alkaline electrolyte. Hence, this work confirmed that 3d transition metals, which are cheap and abundant, could easily achieve high activity and durability by reasonable design.

Stepped-frequency synthetic aperture radar (SAR) system errors induce the periodic magnitude error and phase error (MEPE) in the synthesized wideband spectrum. The periodic MEPE results in periodic grating lobes in the high range resolution profile, which degrade the SAR image quality seriously. This paper presents a data-driven grating lobes suppression (GLS) method, named MEPE-GLS, to suppress grating lobes by estimating and compensating the periodic MEPE. Based on the dominant targets' image domain data, MEPE-GLS estimates the phase error and magnitude error by the weighted maximum-likelihood estimation and weighted least-squares estimation, respectively. In order to improve the signal-to-clutter-and-noise ratio (SCNR) of the data employed in the MEPE estimation, MEPE-GLS applies the discrete windows to selected targets to remove clutters between two adjacent grating lobes. Compared with conventional GLS methods, MEPE-GLS removes grating lobes effectively while at the same time preserves the original image information, and has no restriction on hardware, scenes, and spectrum reconstruction methods. Simulation and real data experiments validate the effectiveness and robustness of MEPE-GLS.

Underwater wet shielded metal-arc welding using three heat inputs were investigated. The columnar microstructures in weld metal contain large amounts of ferrite with second phase aligned and grain boundary ferrite, and some polygonal ferrite and acicular ferrite. The coarse grain heat affected zone (CGHAZ) is dominated by lath martensite and some bainite. The microstructure evolution of the reheated columnar region and CGHAZ is discussed to explain the beneficial effect of temper bead. The unaltered CGHAZ in the top layer is the most preferential sites for cold cracks due to the lack of tempering. Although large heat input can reduce the hardness and the susceptibility of cold cracking, it also degrades the mechanical performance of weld metal owing to the microstructure coarsening and less reheated regions.

Multifunctional nanoplatforms yield extremely high synergistic therapeutic effects on the basis of low biological toxicity. Based on the unique tumor microenvironment (TME), a liposomes (Lips)-based multifunctional antitumor drug delivery system known as GOD-PTL-Lips@MNPs was synthesized for chemotherapy, chemodynamic therapy (CDT), starvation therapy, and magnetic targeting synergistic therapy. Evidence has suggested that parthenolide (PTL) can induce apoptosis and consume excessive glutathione (GSH), thereby increasing the efficacy of chemodynamic therapy. On the other hand, glucose oxidase (GOD) can consume intratumoral glucose, lower pH and increase the level of H2O2 in the tumor tissue. Integrated Fe3O4 magnetic nanoparticles (MNPs) containing Fe2+ and Fe3+ effectively catalyzes H2O2 to a highly toxic hydroxyl radical (•OH) and provide magnetic targeting. During the course of in vitro and in vivo experiments, GOD-PTL-Lips@MNPs demonstrated remarkable synergistic antitumor efficacy. In particular, in mice receiving a 14 day treatment of GOD-PTL-Lips@MNPs, tumor growth was significantly inhibited, as compared with the control group. Moreover, toxicology study and histological examination demonstrated low biotoxicity of this novel therapeutic approach. In summary, our data suggests great antitumor potential for GOD-PTL-Lips@MNPs which could provide an alternative means of further improving the efficacy of anticancer therapies.

Simultaneously enhancing the breakdown strength and the dielectric constant is considered as a trend in material design for increasing energy density of linear dielectrics. Based on this point, crystalline SrTiO3 nanoparticle@amorphous Al2O3 composite film (Au top electrode) is prepared via spin coating process with dielectric strength of 118.1 MV/m and dielectric constant of 23.6. Further, under aluminum top electrode, higher breakdown strength of 342.9 MV/m and superior energy density of 12.2 J/cm3 are realized, which is stemmed from anodic oxidation reaction at the interface between the aluminum electrode and the composite dielectric film. This new composite structure shows an improved energy density, which provides a feasible avenue to design excellent inorganic dielectric composites assimilating the high breakdown strength of amorphous structure and high dielectric constant of crystalline dielectrics.

Since the advent of virtual reality technology, great changes have taken place in modern education and training. It conducts an in-depth study of its fundamental cause, that is, the virtual training method has distinct advantages over the traditional training method. The electric power skill training platform based on the virtual reality technology was established in this paper. Three-dimensional digital modeling of high-risk, invisible, and inaccessible scenarios in electric power industry had been structured by the computer system, in order to construct an immersive virtual environment and the simulation of real-life space would be realized. The electric power skill training platform could provide the somatosensory interaction system to enhance the trainees' simulation experience so that they can feel the authenticity of the training to the greatest extent. Trainees are enabled to have an accurate perception of various objects in the virtual environment through the senses of sight, hearing and touch by applying a variety of high-performance interactive devices, which is beneficial to improve the actual operation level of trainees, improve training quality and training efficiency, and reduce training cost input.

X-ray computed tomography (X-ray CT) is a nondestructive internal core structure characterization technique. With X-ray CT, natural fractures and vugs have been identified in the Y Field, which is a limestone carbonate reservoir in the Middle East. Based on CT images of all core samples, three main core types in the Y Field were identified: matrix, fractured and vuggy carbonate. For core samples with different pore types and structures, the petrophysical properties vary considerably. In this paper, the X-ray CT technique was used to investigate the effect of fractures and vugs on the porosity–permeability relationship, internal heterogeneity of the core samples, permeability and porosity stress sensitivity, and oil–gas relative permeability. The analysis results show that matrix carbonate displays a stronger porosity–permeability relationship compared with that of fractured and vuggy carbonate. Fractured carbonate is very sensitive to the net confining pressure compared with non-fractured carbonate, and vugs increase the porosity stress sensitivity. The oil–gas relative permeability experiment demonstrates that fractures and vugs can provide flow channels and increase gas flowability. In particular, fractures are unfavourable for gas injection and oil recovery is low due to gas channelling.

Highly dispersed Pd nanoparticles supported on amine-functionalized magnetic mesoporous silica nanotubes (NH2-MSNTs) have been successfully prepared and tested in the aqueous phase catalytic hydrodechlorination (HDC) of chlorophenols (CPs). The as-synthesized Pd@NH2-MSNTs catalyst is investigated by transmission electron micrograph (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), Fourier-transfer infrared spectroscopy (FT-IR) and N2 adsorption–desorption. The synthesized MSNTs material exhibits a large surface area of 966 m2 g−1, high pore volume of 0.81 cm3 g−1, highly open mesoporous size of 3.4 nm and high saturation magnetizations of 19.65 emu g−1. For the HDC of CPs, the catalyst shows 100% conversion with 99% selectivity for cyclohexanone in aqueous solution at mild conditions of temperature (60 °C) under ambient pressure. It is astonishing that the Pd@NH2-MSNTs catalyst shows better catalytic performance, and it can synthesize cyclohexanone in one pot, in comparison with other heterogeneous catalysts for which phenol is the only reaction product. The novel heterogeneous magnetic catalyst exhibits excellent catalytic stability and can be used seven times without an obvious decrease of product selectivity. In addition, our study further reveals that the synergetic effect between Pd nanoparticles and NH2-MSNTs support plays a key role in the HDC of CPs.

The different of Ag-11Au-4.5Pd and Ag-11Au-4.5Pd-0.1Y alloy bonding wire mechanical properties, fusing current and structure were analyzed by strength tester, electronic conductivity tester, and scanning electron microscope. The effects of Y on Ag-11Au-4.5Pd and Ag-11Au-4.5Pd-0.1Y alloy bonding wire ball size, bonded micro phonology and bonded strength were investigated. The results show that the elongation and tensile strengths of Ag-11Au-4.5Pd-0.1Y alloy bonding wire increases from 14.55%, 9.4g to 16.35%, 10.2g because of doping Y, and the fusing current of Ag-11Au-4.5Pd-0.1Y alloy bonding is smaller than Ag-11Au-4.5Pd alloy bonding wire, the Ag-11Au-4.5Pd-0.1Y alloy bonding wire bonded strength is higher than Ag-11Au-4.5Pd alloy bonding wire. The heat affect zone length decreases from 60μm to 45μm because of doping Y. For Ag-11Au-4.5Pd-0.1Y alloy bonding wire, Y can refine the grain, then the grain size decreases, and the grain quantity increases, then the inhomogeneous deformation of different grain decrease, and the ball bonded shape is uniform. After HTS test, cracks phenomenon happens at the bonding interface because of Ag atoms rapidly migrate, Y can decrease the Ag migrate rate and avoid the crack in bonded interface.

Prepared with two layers of anodized alumina (Al2O3), a novel structure of multi-layer anodized alumina/Sr0.85Bi0.1TiO3 (AO/SBT) dielectric capacitor has been designed and fabricated to realize significant improvement in energy density. The first Al2O3 layer (AO1) was artificially introduced through anodic oxidation of aluminum layer in electrolyte, while the second Al2O3 layer (AO2) was automatically generated during the I–V testing process. With ultrahigh breakdown strength, the embedded Al2O3 layers could be taken as the patch to repair the micro-holes located at the interface. In addition, they could be used as barrier layers to dramatically reduce the leakage current. More importantly, it was found that the different location of the AO1 layer has enormous impact on the ultimate breakdown strength. Based on finite element analysis, the simulation results showed the electric field was mainly concentrated on the Al2O3 layer, which could effectively reduce the breakdown probability of SBT films. By dual interfacial modification, the multi-layer thin films with an optimal structure show a remarkable enhancement in breakdown strength from 134.09 to 534.72 MV m−1. As a result, the maximum energy density of 29.71 J cm−3 has been achieved, which represents a ∼741% increase in comparison to the samples without dual interfacial modification. The unique dual interfacial modification technology employed in this work offers a new approach to increase the energy storage density of dielectric capacitors from the perspective of structural design.

Polymeric surfactants display different capabilities in migration rules and emulsifying crude oil as compared with that of traditional polymers attributing to the co-existence of hydrophilic and hydrophobic groups in molecular chains. To investigate the migration rules of polymeric surfactants in porous media and the matching relationship between polymeric surfactants and porous media, seepage-behavior experiments of different concentrations of polymeric surfactants in different permeability and different length cores were first carried out. The generation of emulsified oil droplets with the polymeric surfactants was then elucidated by comparing core flooding experiments with different injection rates, different saturated oil types and different polymeric surfactants concentrations. The flow characteristics of the emulsion and displacement mechanisms were evaluated by microscopic displacement experiments. The results showed that unlike polymers, when the polymeric surfactant was transported in porous medium, the pressure was difficult to reach a stable state. Based on the matching coefficient, the migration rules of polymeric surfactants in porous media could be defined as high blocking weak flow mode (λ 19.7). The main reasons for the formation of polymeric surfactants emulsions are a certain shearing action, the snapping action of hydrophobic microdomains on residual oil droplets and assisted effect of colloidal asphaltene. Capillary number(Nc) was used as an evaluation index to divide the emulsification action into four zones: non-emulsified zone(Nc 1.46 × 10−4). The emulsion microscopic flooding experiment showed that in the porous medium, the transport characteristics of polymeric surfactants emulsion were mainly plugging action of single large emulsion particle, stacking and plugging action of small emulsion particles, forming “emulsion bridge” to block super large pores and vortex action of different sizes emulsion particles.

We report that MBE-grown three-dimensional (3D) topological Dirac semimetal Cd 3 As 2 thin-film exhibits remarkable saturable absorption effects at 1, 1.5 and 2 μm. A mode-locked Tm fiber laser is demonstrated using such a SESAM-like material.

The magnitude error and phase error (MEPE) in the transfer function of a stepped-frequency synthetic aperture radar (SAR) system results in a periodic MEPE in the synthesized wideband waveform (SWW), which induces the grating lobes in the high-resolution range profile (HRRP). In this paper, a robust data-driven grating lobe suppression (GLS) method is proposed. Based on a contrast-based error estimation method and the grating lobes of the brightest scatterers in the SAR image, the periodic MEPE can be robustly estimated using the proposed method. By compensating the estimated periodic MEPE, the range grating lobes can be suppressed to the background level of the SAR image. Simulation results and real data processing have demonstrated the superiority of the proposed method.

Conventional methods of moving target detection, such as DPCA, GMTI have difficulties in detecting low speed target and showing the movement route. Multi-aspect airborne SAR can illuminate the same scene from different directions to get all-round scattering features of scene. In this paper, a method of moving target detection based on multi-aspect SAR images is proposed. This method can extract the change part from multi-aspect images to estimate the velocity and show the movement route. There is geometric correction, image registration and change detection along the process. As the key part of the detection, an improved image registration method named WT-SIFT is proposed, which combines Wavelet Transform (WT) with Scale-Invariant Feature Transform(SIFT). Finally, the validity of this method of moving target detection is demonstrated by an airborne multi-aspect SAR experiment.

WTe2 is a unique material in the family of transition metal dichalcogenides and it has been proposed as a candidate for type-II Weyl semimetals. However, thus far, studies on the optical properties of this emerging material have been significantly hindered by the lack of large-area, high-quality WTe2 materials. Here, we grow a centimeter-scale, highly crystalline WTe2 ultrathin film (∼35 nm) by a pulsed laser deposition technique. Broadband pump-probe spectroscopy (1.2–2.5 μm) reveals a peculiar ultrafast optical response where an initial photo-bleaching signal (lasting ∼3 ps) is followed by a long-lived photoinduced absorption signature. Nonlinear absorption characterization using femtosecond pulses confirms the saturable absorption response of the WTe2 ultrathin films, and we further demonstrated a mode-locked Thulium fiber laser using a WTe2 absorber. Our work provides important insights into linear and nonlinear optical responses of WTe2 thin films.