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The high throwing power (TP) value is one of the most important parameters for the Cu electroplating of through-holes in flexible printed circuit (FPC). It was found that an ultra-high TP value could be obtained using a specific suppressor, i.e., iodonitrotetrazolium chloride (INT) in the electrolyte. The ultra-high TP value was attributed to fast-consumption of this suppressor instead of traditional convection-dependence adsorption mechanism. A consumption model was built and simulated to clarify the formation of the ∆θ, i.e., the difference of suppressor fractional coverage between the entrance and center of through-holes sidewalls. It revealed that the TP, proportional to the ∆θ, was determined by the consumption rate of a suppressor. This simulation results were well consistent with the results of electroplating using INT with different concentration. The electrochemical analysis verified the characteristics of fast consumption of INT due to the reduction reaction. The difference of residual INT between the entrance and center of the plated through-holes confirmed the occurrence of ∆θ. These results supported the opinion that the ultra-high TP value was obtained by fast-consumption mechanism of INT suppressor.

Influence of coiling temperature (CT) on the microstructure and mechanical properties of a hot-rolled high-strength steel microalloyed with Ti, Mo and V was elucidated. The precipitation behavior of nano-sized particles was investigated by theoretical calculation and quantitative analysis. And the results revealed that V-enriched (Ti, Mo, V)C precipitated in the ferrite matrix. As the CT decreased, the site fractions of Ti in (Ti, Mo, V)C changed little, the site fractions of Mo increased, and the site fractions of V decreased accordingly. Moreover, the low CT could refine the microstructure and precipitated particles but suppress the precipitation of (Ti, Mo, V)C particles simultaneously, leading to the volume fraction of (Ti, Mo, V)C significantly decreasing, consequently causing an increment of grain refinement strengthening and a reduction in precipitation hardening. When the CT was 600 °C, the steel characterized by fine polygonal ferrite, a small amount of bainite and nano-sized (Ti, Mo, V)C precipitates exhibited the optimum mechanical properties with the ultimate tensile strength of 870 MPa, yield strength of 807 MPa and elongation to fracture of 17%.

The continuous cooling transformation (CCT) diagram of 30CrMo steel simulated by compact strip production process was constructed. And the effect of austenite deformation on the CCT behaviour was i...

Semitransparent polymer solar cells (STPSCs) are a potential photostatic structure for building-integrated photovoltaic (BIPV) application. In order to realize the application practically, the balance between efficiency, transparency, and color property is a challenge in the field. In this paper, efficient semitransparent polymer solar cells utilizing P3HT:ICBA as active layers were demonstrated. By introducing ZnSe/LiF distributed Bragg Reflector (DBR) onto the device, the power conversion efficiency (PCE) has been increased to 6.19%. In addition, this approach can also improve the color render property by leveling the transmittance spectrum. The highest color-rendering index (CRI) is achieved using device with 1 pair of DBR. As a result, the high efficiency and fine CRI confirmed that the STPSC with DBR is an effective structure for BIPV application.

The rapid and accurate measurement of in situ stress fields is one of the essential steps in geological engineering. Indoor acoustic emission tests and the Kaiser effect provide a promising prior peak stress measurement method. This paper aims to qualitatively explore the time delay mechanism of the Kaiser effect under uniaxial compressive stress. Acoustic emission tests were conducted with natural and water-soaked sandstone specimens to examine the time delay phenomenon of the Kaiser effect, and the typical Griffith fracture mechanics theory was adopted to explain the mechanism. The time delay of the Kaiser effect under uniaxial compressive stress was affected by the friction coefficient on the crack surfaces and the initial crack angle $$\beta$$ . The time effect was indirectly induced by the changes in the friction coefficient on the crack surfaces, and the friction coefficient was controlled by the water content in the rock specimen. A higher initial friction coefficient led to an earlier and easier time delay of the Kaiser effect. Consequently, from the aspect of the Kaiser effect, it was suggested that when testing in situ stress, measures should be taken to maintain the original moisture contents in the rock cores after they are drilled underground. Otherwise, the in situ stress should be tested within 7 days.

The research on graphene-based anode materials for high-performance lithium-ion batteries (LIBs) has been prevalent in recent years. In the present work, carbon-coated SnO2 riveted on a reduced graphene oxide sheet composite (C@SnO2/RGO) was fabricated using GO solution, SnCl4, and glucose via a hydrothermal method after heat treatment. When the composite was exploited as an anode material for LIBs, the electrodes were found to exhibit a stable reversible discharge capacity of 843 mA h g−1 at 100 mA g−1 after 100 cycles with 99.5% coulombic efficiency (CE), and a specific capacity of 485 mA h g−1 at 1000 mA g−1 after 200 cycles; these values were higher than those for a sample without glucose (SnO2/RGO) and a pure SnO2 sample. The favourable electrochemical performances of the C@SnO2/RGO electrodes may be attributed to the special double-carbon structure of the composite, which can effectively suppress the volume expansion of SnO2 nanoparticles and facilitate the transfer rates of Li+ and electrons during the charge/discharge process.

In deep underground engineering, understanding of time-related stress memory properties is critical to evaluate the in situ stress conditions of a rock mass. In this study, the time-sensitivity mechanism of the rock stress memory properties under tensile stress was investigated. It was found that the material property (Poisson's ratio) and crack angle were the controlling factors of the Kaiser effect (KE) under tensile stress. In particular, the time-sensitivity of the stress memory properties was closely related to the crack growth path. When the failure of the rock specimen was dominated by tensile microcracks and the crack development direction was deflected by up to 30° in the successive loading process, the stress memory capacity was likely to be time-independent for a sandstone specimen. The distribution of the Felicity ratio in a Brazilian test was more discrete than that in a three-point bending test. It also showed that the changes in the crack path, rather than the time interval between successive loading cycles, led to inaccuracy of the detected KE. This study provides insights into stress memory-related issues under uniaxial or more complex stress conditions and thus facilitates development of methods for testing in situ mechanical behaviors of rocks with acoustic emission (AE) technology.

Surface micro/nano processing is an important method and research hotspot for enhancing the boiling heat transfer process. However, the effects of a structural gradient on a boiling surface have not been systematically studied. In this paper, we review researches that focus on porous surfaces with a structural gradient and their effects on the enhancement of boiling heat transfer and performance of phase-change devices from two main aspects: Geometric gradient and wettability gradient. Porous surfaces with a geometric (structural) gradient were divided into four series: single-layer geometric gradient structure, multi-layer geometric gradient structure, surface covered with a micro/nanolayer, and surface with a radial gradient. In addition, the surface with a wettability gradient also has a considerable improvement in boiling heat transfer. Especially, we present some of the work related to the improvement in boiling heat transfer for porous surfaces with structural gradient, which has been carried out by our research group. Honeycomb-like and forest-like porous copper surfaces are typical single-layer geometric gradient porous surfaces with excellent boiling heat transfer performance. They have abundant microstructures and sub-microstructures/nanostructures, which are favorable for vapor escaping and liquid rewetting, respectively. For all the mentioned single-layer geometry gradient porous surfaces, the critical heat flux increases as the sample thickness increases. Furthermore, we fabricated a two-layer composite porous surface (TLCS) with a honeycomb-like porous copper surface on top of a forest-like porous copper surface. This TLCS is a multilayer geometric gradient structure porous surface that can further enhance the boiling heat transfer process. The heat transfer coefficient (HTC) of TLCS is 1.5 and 1.2 times larger than those of the biomimetic copper forest and honeycomb structures, respectively. When a small current is applied to the honeycomb-like porous copper surface, the dendrites on the pore wall transferred to micro balls and a surface with a structural gradient is obtained. The modified surface is a microstructural porous surface covered by a nanolayer that further enhances the HTC (1.7 times). The diameter of the honeycomb-like porous copper surface can be controlled with a radial diameter gradient. A sample in which the diameter around the center is much smaller than that around the edge enhances the HTC 1.4 times compared with a sample with uniform diameter. When the TLCS was modified with polytetrafluoroethylene (PTFE), it became a hybrid wetting surface. The experimental results show that the wall superheat temperature at the same heat flux during the heat flux decreasing can repeat that during the heat flux increasing well within 0.5°C, demonstrating that the boiling hysteresis was successfully eliminated. As the porous surface with a structural gradient has excellent performance in boiling heat transfer, it has been widely used in phase-change devices, such as loop and flat heat pipes, to improve their functioning. An ultra-thin flat heat pipe (UTHP), which is only 0.6 mm thick, can significantly reduce the evaporator temperature by 10°C under a 6 W heat load compared with a copper plate. This paper summarizes the most relevant features related to boiling heat transfer enhancement when using structural-gradient porous surfaces and the improvements in phase-change devices that use such surfaces. Despite the advances in this aspect, the porous surfaces can be further optimized to achieve a better heat transfer performance.

Photocatalytic TiO2/cement composites were prepared by a smear method with a slim thread, through floating TiO2/waterproof emulsion mixture onto the pre-wet surfaces of cement pastes/mortars. The composition, microstructure, hydrophobicity, photocatalytic properties and durability of the prepared TiO2/cement composites were systematically studied. The results showed that TiO2 particles were dispersed equally on the surfaces of the cement pastes. The TiO2/cement paste composites had good hydrophobic property with contact angle of 145.2 °C. Under UV irradiation, the photocatalytic cement pastes could almost completely degrade 10 mg L−1 Rhodamine B (RhB), methylene blue (MB) and methylene orange (MO) in 50 min. After soaking in acid or alkaline solution, the photocatalytic cement pastes had better degradation performance than before soaking. Good cycling performance was achieved for the photocatalytic cement pastes. In the aspect of durability, the photocatalytic cement mortars had good water permeation resistance, chloride penetration resistance and carbonation resistance.

Tactile sensors are of great significance for robotic perception improvement to realize stable object manipulation and accurate object identification. To date, developing a broad-range tactile sensor array with high sensitivity economically remains a critical challenge. In this study, a flexible capacitive tactile sensor array, consisting of a carbon nanotube (CNT)/polydimethylsiloxane (PDMS) film, parylene films, and two polyimide (PI) films patterned with electrodes, is facilely prepared. The CNT/PDMS film, acting as a giant dielectric permittivity material, is utilized to improve the sensitivity, while the parylene film serves as the scaffold architecture to extend the working range of the tactile sensor array. Also, it is promising to realize mass production for this sensor array due to the scalable fabrication procedure. The as-prepared sensor exhibits excellent sensing performance with a high sensitivity of 1.61% kPa−1 (

Fibrous supercapacitors have garnered great interest from researchers because of their large electrode/electrolyte interface area, short ion transport path, and high flexibility. However, obtaining a thin gel electrolyte interlayer with a high ion transport rate and uniform thickness is still challenging. Here, we proposed an efficient wet-spinning technique to fabricate uniform polyvinyl-montmorillonite tubular layers for the preparation of a high-performance coaxial asymmetry fibrous supercapacitor (AFSC). The coaxial AFSC shows ultrahigh energy densities in the range of 2.86-4.04 μW h cm-2 at power densities of 0.16-1.61 mW cm-2 while maintaining a long cycling life (94% retention even after 20 000 cycles). After charging at a constant voltage of 2.4 V for 30 s, the flexible watchband which is composed of three series-connected AFSCs could power a commercial electronic watch for more than 2 min. This work provides a universal strategy to fabricate high-performance and wearable energy storage devices.

Transfer chutes for bulk material conveying systems have significant importance in ship loading and unloading and are ‘worn’ from large mass flow and fast granular material flow conditions. In this investigation, the impact forces of different granular materials on the transfer chute wear process are considered, the DEM–FEM (Discrete Element Method–Finite Element Method) coupling method was used to calculate the wear and the deformation of the transfer chute. The stress–strain and cumulative contact energy from three different granular materials were analyzed under different working conditions. The results show that the wear, stress–strain, and cumulative contact energy of the transfer chute are closely related to the belt speed, the chute inclination angle, and the types of granular materials, the impact force and the stress–strain on the transfer chute achieves maximum value under a 4 m/s belt speed condition, meanwhile, with the increase of belt speed by 0.5 m/s, the wear of the transfer chute increases 25% and the deformation increases 20%, the shape variable, wear area, and normal cumulative contact capacity of the transfer chute are the smallest with a transfer chute inclination angle from 40° to 45°.

To reveal the evolution law of coal skeleton deformation during the process of CO2 flooding and displacing CH4 in coal seam, a fluid-solid coupling mathematical model of CO2 injection enhanced CH4 drainage was established based on Fick’s law, Darcy’s law, ideal gas state equation, and Langmuir equation. Meanwhile, numerical simulations were carried out by implementing the mathematical model in the COMSOL Multiphysics. Results show that the CH4 content of both regular gas drainage and CO2 enhanced gas drainage gradually decreases with time, and the decreasing rate is high between 10 and 60 days. Compared with regular gas drainage, the efficiency of CO2 enhanced gas drainage is more obvious with greater amount of CH4 extracted out. When coal seam gas is extracted for 10, 60, 120, and 180 days, CH4 content in coal seam is reduced by 5.2, 17.2, 23.6, and 26.7%, respectively. For regular gas drainage, the deformation of coal skeleton is dominated by the shrink of coal matrix induced by gas desorption, and the strain curve shows a continuous downward trend. For CO2 enhanced gas drainage, the strain curve of coal skeleton showed a decrease—rapid increase—slow increase trend. The evolution of permeability is opposite to the evolution of coal skeleton strain. Higher gas injection pressure will lead to a greater coal skeleton strain. The pumping pressure affects the deformation of coal skeleton slightly compared with that of initial water saturation and initial temperature. Greater initial water saturation leads to larger deformation of coal skeleton in the early stage. The strain value of coal skeleton gradually tends to be consistent as gas injection prolongs. Higher initial temperature leads to greater reduction in coal skeleton strain when the gas injection continues. Research achievements provide a basis for the field application of CO2 injection enhanced CH4 drainage in underground coal mines.

Highlights Shape memory self-soldering tape used as conductive interconnecting material. Perfect shape and conductivity memory performance and anti-fatigue performance. Reversible strong-to-weak adhesion switched by temperature. Abstract With practical interest in the future applications of next-generation electronic devices, it is imperative to develop new conductive interconnecting materials appropriate for modern electronic devices to replace traditional rigid solder tin and silver paste of high melting temperature or corrosive solvent requirements. Herein, we design highly stretchable shape memory self-soldering conductive (SMSC) tape with reversible adhesion switched by temperature, which is composed of silver particles encapsulated by shape memory polymer. SMSC tape has perfect shape and conductivity memory property and anti-fatigue ability even under the strain of 90%. It also exhibits an initial conductivity of 2772 S cm−1 and a maximum tensile strain of ~ 100%. The maximum conductivity could be increased to 5446 S cm−1 by decreasing the strain to 17%. Meanwhile, SMSC tape can easily realize a heating induced reversible strong-to-weak adhesion transition for self-soldering circuit. The combination of stable conductivity, excellent shape memory performance, and temperature-switching reversible adhesion enables SMSC tape to serve two functions of electrode and solder simultaneously. This provides a new way for conductive interconnecting materials to meet requirements of modern electronic devices in the future.

The soil-rock mixture (S-RM) is widely used as a kind of geotechnical material in some construction engineering. When analyzing the stability of the engineering, the strength properties of S-RM are used as crucial input parameters. In this paper, to improve the understanding of strength properties of S-RM, a series of large-scale direct shear tests were conducted on S-RM with two volumetric rock block contents (VBCs), each with three types of block lithology. The particle breakage after each test and its relationship with strength properties were also analyzed. The results reveal that the influences of VBC and block lithology on particle breakage are slight when VBC is low, while significant as VBC increases. Compared with the traditional M-C strength criterion, a modified M-C nonlinear strength criterion is more suitable for the S-RM. When VBC is low, the influences of VBC and block lithology on the strength properties are slight. However, when VBC is high, their impacts will become greater, especially on the nonlinear strength parameter Δφ. The nonlinear strength characteristics become more obvious with an increase in relative breakage index Br, which are mainly caused by the particle breakage during the shearing process.

Two new sets of UiO-Zr metal-organic framework (MOF) bearing mixed linkers BDC-(SCH3)2 and BDC-(SOCH3)2 that have different band gaps and edges were prepared through post oxidation and direct methods, namely, UiO-66-(SCH3)2-xh (x = 4, 9, 12 oxidation hours) and UiO-66-(SOCH3)x(SCH3)2-x (x = 0, 0.4, 0.6, 2), respectively. These composites with stoichiometric components were fully characterized via proton nuclear magnetic resonance (1H NMR) spectroscopy, powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectra, Brunauer-Emmett-Teller (BET), photo electrochemical measurements, and femtosecond transient absorption (fs-TA) spectroscopy. The structure, electronic property, and photoresponsive and catalytic ability as the functions of the molar ratio of linkers and the synthetic protocol were first investigated. The mixed-linker UiO-66-(SCH3)2-xh and UiO-66-(SOCH3)x(SCH3)2-x exhibited improved performances as compared to the UiO-66-(SCH3)2 and UiO-66-(SOCH3)2 possessing neat linkers only. Their photo response and catalytic activity varied with different linker ratios. For UiO-66-(SCH3)2-xh, the performance increased with the increasing linker BDC-(SOCH3)2 ratio upon oxidation but reached the highest as the BDC-(SOCH3)2 being of 24.4% in UiO-66-(SCH3)2-9h. In comparison, the best photocurrent (80.74 uA/cm-2) and the highest H2 generation rate (2018.8 μmol g-1 h-1) (λ > 400 nm) in UiO-66-(SCH3)2-9h are about twice those of UiO-66-(SOCH3)0.4(SCH3)1.6 obtained by direct synthesis, although the linker BDC-(SOCH3)2 ratio of those two composites is almost the same (24.4% vs 23.9%). Recorded shorter lifetime and higher charge separation efficiency of the former than those of the latter suggest the postsynthetic protocol as the efficient method for achieving the mixed-liner-MOF-based photocatalyst with high performance. A new type-II tailored homojunction is proposed in these mixed-linker MOFs for their efficient charge separation and improved activity.

The corresponding relationship between the fracture geometrical morphology of laminar shale and the acoustic emission (AE) power spectrum characteristics was established to further reveal the shale microdamage mechanism. Laboratory Brazilian tests coupled with AE and digital image correlation (DIC) were conducted on black shale disks. The amplitude–time–dominant/second dominant frequency values of AE waveforms from the entire loading process were extracted with the function package PSD in MATLAB. The geometrical morphology of shale disk fracture is the result of a dynamic balance of microcracks, spatial anisotropy, local heterogeneity of the shale specimen, and the stress condition. There is a corresponding relationship between the distribution of dominant/second dominant frequency and shale internal microdamage. Four factors contribute to the shale specimen final failure, including the tearing of the shale matrix induced by local tensile failure (high dominant/second dominant frequency components at approximately 300 kHz), shearing on the bedding layer (middle dominant/second dominant frequency components at approximately 200–250 kHz), opening of the bedding layer induced by the weak structural plane, and friction on the microcrack surface (low dominant/second dominant frequency components at approximately 150 kHz). The fracture mainly controlled by the shale matrix tearing is flexible in profile because it is greatly affected by the competition of microcracks and local natural defects in the process of initiation and propagation. The fracture controlled by the opening of the bedding layer is a straight line with the rough surface and the fracture controlled by the shearing on the bedding layer is a straight line with the smooth surface. Finally, the fracture predominantly controlled by friction on the microcrack surface is generally arched. This work is helpful in providing considerations for depicting the probable fracture planar profile and explaining the microdamage mechanism, allowing for the enhancement of human control when constructing complex underground fracture networks in shale reservoirs.

A MnCO₃ /Multiwalled carbon nanotube (MnCO₃/MWCNT) composite has been successfully fabricated by an in-suit hydrothermal method. When the MnCO₃/MWCNT composite is applied as anode materials in lithium-ion batteries (LIBs), the electrodes exhibit a reversible capacity of 645 mA h g-1 at 100 mA g-1 after 80 cycles, reaching an initial coulombic efficiency (CE) of up to 60.6%. Furthermore, the as-prepared MnCO₃/MWCNT composite displays more excellent rate performances than the pure multiwalled carbon nanotube (MWCNT) and pure MnCO₃ particles. The reason is that the MnCO₃ particles can be effectively connected by the MWCNT, thus enhancing the electrochemical performance of the MnCO₃/MWCNT composite.

A NiO flake and reduced graphene oxide sheet (NiO/RGO) composite was synthesized via an in situ ultrasonic agitation method after heat calcination in a nitrogen atmosphere. The NiO/RGO composite displayed a high reversible capacity of 825 mA h/g after 50 cycles at 100 mA/g, which was higher than the pure NiO flakes (197 mA h/g). The RGO sheets (115 mA h/g) used in lithium-ion batteries as anode materials. The NiO/RGO electrode showed excellent rate capacities that were higher than the pure NiO flakes and the RGO sheets electrodes within the same experimental conditions. These improvements could be attributed to the RGO sheets improved the electrical conductivity of NiO flakes and buffered the volume expansion of the NiO/RGO composite electrode during lithium cycling.

In this paper, a type of macroporous carbon (MPC) material was produced using water-soluble sodium carbonate (Na2CO3) as the template and glucose as the carbon precursor. After annealing in an argon atmosphere (Ar) at 700 °C, the samples exhibited specific surface areas up to 600 m2 g−1 with different proportions of sodium carbonate and glucose. When the samples were employed as anode materials in lithium-ion batteries, the electrodes delivered a stable reversible capacity at 200 mA g−1 and favourable cycling stability at 500 mA g−1. Moreover, all MPC samples exhibited excellent rate performances at 5000 mA g−1.

An N-doped MnO/rGO composite (N-MnO/rGO) was successfully fabricated by a one-step hydrothermal method in which histidine and potassium permanganate (KMnO4) reacted in water containing graphene oxide, and the product was then calcinated in a nitrogen (N2) atmosphere. The N-MnO/rGO presents an excellent lithium-storage capability. It shows a high reversible specific capacity of 1020 mA h g−1 at a current density of 200 mA g−1 after 150 cycles and 760 mA h g−1 at a current density of 500 mA g−1 after 200 cycles. Meanwhile, the N-MnO/rGO sample presents a stable rate capability from 100 to 2000 mA g−1. Even at 2000 mA g−1, the electrode delivers 335 mA h g−1, which is higher than the capability for the pure MnO particles and rGO sheets. The outstanding electrochemical performances of the N-MnO/rGO electrodes may be attributed to the combined effect of the rGO with N-doping that can effectively buffer the large volume expansion of the MnO particles and can enhance the transport rates of lithium ions and electrons during lithium cycling.

NiO-ZnO/RGO composite was obtained by the annealing of an Ni (OH) 2 -Zn (OH) 2 /RGO precursor, which has been fabricated by in situ ultrasonic agitation. Moreover, the NiO-ZnO nanoflakes are evenly distributed on the RGO sheets based on the scanning electron microscope (SEM) and transmission electron microscope (TEM) characterization results. When the NiO-ZnO/RGO composite was used as an anode material in lithium-ion batteries (LIBs), the electrodes exhibited a high reversible capacity of 1017 mA h/g at a current density of 100 mA/g after 200 cycles and a specific capacity of 458 mA h/g at 500 mA/g even after 400 cycles. The electrode even reached a capacity of 185 mA h/g at a current density of 2000 mA/g. The excellent electrochemical properties of the NiO-ZnO/RGO composite might be attributable to the NiO-ZnO nanoflakes offering rich electrochemical reaction sites and shortening the diffusion length for lithium ion (Li + ), as well as the RGO sheets improving the transfer rates of Li + and electron during the charge-discharge process.

Polymer nanocomposites based on carbon nanotubes attract a great deal of attention recently due to their excellent performance. The dispersion state of CNTs embedded in the matrix is the primary and key issue to realize the potential of the nanocomposite. Here, this paper considers how the boiling point of solvent affects the performance of the nanocomposite when the ultrasonication dispersion method is employed. It is found that solvent with a low boiling point is conducive to save evaporation time so that CNTs can maintain the homogenous dispersion state as much as possible after ultrasonication. Therefore, the stretchability and tensile strength can be improved, while the electrical conductivity has an obvious enhancement as well.

Owing to the growing interest in the application of Raman spectroscopy for quantitative purposes in solid pharmaceutical preparations, an article on the identification of compositions in excipient dominated drugs based on Raman spectra is presented. We proposed label-free Raman spectroscopy in conjunction with deep learning (DL) and non-negative least squares (NNLS) as a solution to overcome the drug fast screening bottleneck, which is not only a great challenge to drug administration, but also a major scientific challenge linked to falsified and/or substandard medicines. The result showed that Raman spectroscopy remains a cost effective, rapid, and user-friendly method, which if combined with DL and NNLS leads to fast implantation in the identification of lactose dominated drug (LDD) formulations. Meanwhile, Raman spectroscopy with the peak matching method allows a visual interpretation of the spectral signature (presence or absence of active pharmaceutical ingredients (APIs) and low content APIs).

Heavy-metal ions detection conventionally relies on standard instruments that are complicated, time-consuming and constrained to laboratories. To mitigate this problem, we developed a hand-held and cost-effective smartphone-integrated analysis platform that allows fast identification of heavy-metal ions pollution caused by industrial wastewater discharge. This portable platform integrates a colorimetric sensor array consisting of plasmonic nanocolorants and organic chromophores to detect typical heavy-metal ions at the ppm level within 15 s. The image of the colorimetric sensor array is transmitted to the Complementary metal–oxide–semiconductor (CMOS) imager of the smartphone via 96 individual optical fibers, generating RGB differential fingerprints and quantitatively analyzed by pattern recognition algorithms. Facile identification of 13 common heavy-metal ions (Hg2+, Cd2+, Cr6+, Pb2+, Ni2+, Se4+, Mg2+, Ba2+, Zn2+, As3+, Mn6+, Fe3+, Cu2+) was demonstrated using several different multivariate analyses of the digital data library, including principal component and hierarchical cluster analysis. Furthermore, we demonstrated the multiplexed detection and classification of 4 typical industrial wastewater models (Electroplating, Battery, Metallurgical, Pesticide wastewater) and real water samples with this portable platform, and achieved good discrimination and reproducibility. Combined with edge computing of smartphones and Internet-of-Things (IoT) cloud infrastructure, the portable platform shows feasible potential for pollution traceability, environmental monitoring, and water quality analysis.

This paper presents a novel highly sensitive and flexible tactile sensor based on the fabrication of truncated pyramid-shaped porous graphene nanoplate (GNP)/silicone rubber (SR) composites as the sensing material. The designed tactile sensor has 3 × 3 (=9) sensing units, each unit has three layers: top cover layer with upper electrodes, middle truncated pyramid-shaped porous composite sensing materials, and substrate layer with bottom electrodes. The fabrication processes to make the truncated pyramid-shaped porous piezoresistive sensing material and tactile sensor were developed. The prepared porous GNP/SR composites possess extremely high sensitivities of 8.45 kPa−1 at 0–55 kPa and 195.02 kPa−1 at 55–80 kPa for pressure sensing, its Young's modulus is generally low (∼85.72 kPa), and can endure large strain over 60%. The sensing performances of the fabricated tactile sensor were also characterized, results show that the tactile sensor has high sensitivity, good dynamic response, and repeatability under cyclic pressure sensing. Human body wearing experiments were performed and results demonstrate that the developed tactile sensor was able to detect the distributed motion signals as well as human physiological signals such as pulse accurately, indicating that the proposed tactile sensor has great potential for human motion and health monitoring.

Quantitative evaluation of the fracture morphology of shale is an essential prerequisite for assessing the complexity of hydraulic fracturing fracture networks during shale gas exploitation. Brazilian tests coupled with digital image correlation and acoustic emission technique were conducted on black shale in Sichuan Basin in China, the corresponding relationships between the characteristics of the frequency band of acoustic emission power spectra and the micro-damage mechanism of rock specimens were established, and the fracture morphology was quantitatively evaluated. The bedding layer leads to the differences in power spectra characteristics, micro-damage mechanism and fracture morphology of shale. The tension and shear failure of shale matrix induce high-frequency acoustic emission signals, and the tension and shear failure of shale bedding induce low-frequency acoustic emission signals. With the increase of the angle between the bedding layer and loading direction, the dominant frequency and secondary dominant frequency gradually diffuse from low-frequency band to high-frequency band, and the quantitative ratio of high frequency to low frequency H:L gradually increases. The H:L of 0° shale specimen is 4.28%: 95.72%, and the fracture is a straight line in shape. The H:L of 30° and 60° shale specimens are 15.89%: 84.11% and 36.93%: 63.07% respectively, and their fractures are arched in shape. The H:L of 90° specimen is 93.85%: 6.15%, and the fracture is composited arc-straight line in shape. The results can provide references for analyzing micro-seismic data in situ, and provide a theoretical basis for controlling fracture trajectory in hydraulic fracturing in shale reservoirs.

In recent years, the increasing demand for flexible and wearable devices requires the synthesis of novel stretchable and piezoresistive materials. Piezoresistive polymer composites are popular due to their excellent piezoresistivity and high stretchability, which can readily be attached to clothes or human body. In this study, a stretchable and sensitive strain sensor based on multi-wall carbon nanotube (MWCNT)/polydimethylsiloxane (PDMS) composite with an excellent overall performance was fabricated in a facile and effective way. The composite with 7% MWCNTs is ideal for strain sensor compared to those with 5% and 9% MWCNTs. Not only can the gauge factor reach 5–9 under 10–40% strain, but also the curve of relative change in resistance versus strain is almost linear. The strain sensor can respond immediately with low hysteresis. The strain sensor also exhibits great stability under 1000 cycles of stretching/releasing, demonstrating the desirable long-term endurance to mechanical stimuli as well. The strain sensor was then implemented to monitor human motions (finger and wrist bending), precisely sensing the motion deformation and states. In conclusion, the reported sensor based on MWCNT/PDMS composite possesses numerous favorable characteristics including high sensitivity, good stretchability, ease of fabrication, and promising practical application in the field of biomedical system and wearable electronic devices.

The elastic polymer composite embedded with carbon nanotubes (CNTs) is an ideal candidate for stretchable and flexible sensor fabrication due to the perfect combination between the excellent properties of CNTs and the high stretchability of the elastomer. A cube model of nanotube/polymer composite is constructed to comprehensively and theoretically analyze its electrical behavior, which is dominantly governed by the CNT network. The aspect ratio and alignment of CNTs significantly influence both the percolation threshold range and the electrical conductivity; however, the electrical conductivity of CNTs has little impact on the percolation threshold. The piezoresistivity of the composite is not only governed by the property of CNTs but also by the mechanical property of the polymer matrix, including the Poisson’s ratio and alignment of CNTs. The specific reasons why the composite resistance rises when it is stretched are investigated. Finally, one optimizing suggestion is given for making the CNTs/polymer composite with high sensitivity.

The role human hair plays on the solar ultraviolet (UV) transmission in the skin has been investigated regarding melanoma development in our previous work. However, due to the lack of knowledge about the optical properties of human hair medulla, hair has always been modelled as a homogenous structure in Monte Carlo (MC) simulations of photon transport in skin. In this paper, we have estimated the ratio range of the absorption to attenuation coefficient of hair medulla, in order to examine how the presence of medulla would affect the solar UV transmission in the skin. This was simulated in TracePro™ software with the implementation of the MC method for photon transport. The results show that medullated and non-medullated terminal hairs have similar shielding effects against solar UV transmission into skin.

Fusiform shape MnO/C composite was fabricated for the first time by heat calcining of MnCO3/C precursor, which was produced via a two-step hydrothermal method using glycine, KMnO4 and glucose as reagents. When the composite applied in LIBs as anode materials, the electrodes deliver a reversible capacity as high as 691 mA h g−1 after 120 cycles at a current density of 100 mA g−1 and can retain a stable capacity of 187 mA h g−1 at 1000 mA g−1. Compared with pure MnO particles sample, the enhanced electrochemical performances of MnO/C electrodes were attributed to the carbon layers can effectively improve the transfer rate of electrons and buffer the volume expansion of MnO particles during the charge/discharge process.

Ternary organic solar cells (OSCs) hold great promise in enabling the roll-to-roll printing of environmentally friendly, mechanically flexible, and cost-effective photovoltaic devices. Nevertheless, many ternary OSCs display the best power conversion efficiency (PCE) with a thin active layer at the thickness of about 100 nm, which can be hardly translated in to the roll-to-roll processing with high reproducibility. In this paper, the ternary OSCs with a high PCE and a thick active layer were reported, which was obtained by incorporating a dye small molecule named as 2’-(5,5’-(9,9-dioctyl-9H-fluorene-2,7-diyl)bis(thiophene-5,2-diyl))bis(methanylylidene))-bis(3-ethyl-2-thioxothizolidin-4-one) (FTR)) into a PTB7-Th:PC71BM binary system. Specifically, the addition of FTR into the PTB7-Th:PC71BM binary system was found to improve the hole mobility of the active layer, which resulted in faster charge transport, more efficient charge separation, and higher PCEs even in the presence of a thick active layer. The single-junction PTB7-Th:FTR:PC71BM ternary OSCs with the active layer thickness of 160 nm presented an outstanding PCE of 9.4%, which was much higher than that 7.5% of the PTB7-Th:PC71BM binary OSCs with the active layer thickness of 160 nm. Notably, the PTB7-Th:FTR:PC71BM ternary OSCs devices exhibited excellent thickness insensitivity. In other words, the PTB7-Th:FTR:PC71BM ternary OSCs device with a thick active layer (200 nm) could still demonstrate a high PCE of over 8.2%, which was well compatible to the requirement for future roll-to-roll printing.

A film containing three dimensional Bi2S3 nanowires network was obtained using Bi(NO3)3 and thioacetamide as starting materials through three steps, namely the chemical synthesis of Bi2S3, preparation of its sol under ultrasonic condition and crystal self-assembly at 25 °C. The nanowires had diameters of 20–100 nm. The formation mechanism of the 3D nanowires network is the anisotropic growth of Bi2S3. The sensor based on 3D Bi2S3 nanowires network with an excellent response to ammonia at 30 °C. The response mechanism of the sensor for ammonia is a weak coordination adsorption of ammonia molecule on the Bi2S3 nanowires and the electron is partially transferred from ammonia molecule to bismuth (III) ion. The maximum response of the sensor to ammonia was up to 82.3 and had a good linear range from 30 to 350 ppm concentration, indicating its potential applications in the determination and leak alarm of ammonia.

The word-line (WL)-position dependence of memory cell's threshold-voltage fluctuation (ΔVth) in 3D charge trapping flash (CTF) caused by random telegraph noise (RTN) was studied. Contrary to planar NAND flash, test results show that WL0 has wider accumulative distributions of ΔVth than WL63 in 3D CTF NAND. Transmission electron microscopy (TEM) results show that grain size (GS) decreases by 14.6% from top WLs to bottom WLs. As a result, grain boundary density increases from top to bottom, which corresponds to a larger ΔVth. Moreover, despite the similar transconductance (Gm) trend in planar and 3D Flash memories, WL31's RTN hardly changed with altered RS and RD in CTF memory. These experimental results indicate that Gm is not the dominant factor of RTN in 3D CTF, but the physical properties of the polycrystalline silicon (poly-Si) channel.

The stability, ferroelectricity, and electronic structure of R3c-MgSnO3 and R3c-MgSnO3 under compressive strain were investigated by density functional theory. The calculated phonon frequencies and elastic coefficient indicated that MgSnO3 and MgSnO3 under compressive strain could meet dynamic and mechanical stability. The phonon frequencies, elastic coefficient, and mechanical property have been increased in MgSnO3 under compressive strain, which is explained by the bond length, Bader charge, and electronic structure. The bandgap of R3c-MgSnO3 under compressive strain has been increased to 3.8 eV with an indirect bandgap to enhance optical transparency, which agrees with the experiment. The ferroelectric stability and polarization strength could also be promoted by the compressive strain in MgSnO3. The stability, ferroelectric, mechanical, and photoelectric properties of R3c-MgSnO3 could be controlled by compressive strain.

Micro pin fin arrays have been widely used in electronic cooling, micro reactors, catalyst support, and wettability modification and so on, and a facile way to produce better micro pin fin arrays is demanded. Herein, a simple electrochemical method has been developed to fabricate copper vertical micro dendrite fin arrays (Cu-VMDFA) with controllable shapes, number density and height. High copper sulphate concentration is one key point to make the dendrite stand vertically. Besides, the applied current should rise at an appropriate rate to ensure the copper dendrite can grow vertically on its own. The Cu-VMDFA can significantly enhance the heat transfer coefficient by approximately twice compared to the plain copper surface. The Cu-VMDFA may be widely used in boiling heat transfer areas such as nuclear power plants, electronic cooling, heat exchangers, and so on.

The elastic and photocatalytic properties of multiferroic material InFeO3 under strain are calculated through density functional theory. The calculated results indicate that the intrinsic InFeO3 and the strained InFeO3 meet the mechanical stability conditions and hold a relatively larger elastic coefficient than popular multiferroic material BiFeO3. The calculated bandgap and band edge of InFeO3 under tensile strain show that InFeO3 could be a high-efficiency photocatalytic hydrogen production material. InFeO3 under tensile strain holds the ability of photocatalytic water splitting to produce hydrogen with excellent ferroelectric, mechanical properties and absorption of visible light.

AlGaN-based deep ultraviolet (DUV) light emitting diodes (LEDs) are irradiated by fast neutrons, with optical and electrical properties analyzed in detail. Significant enhancement of output power is observed under neutron irradiation fluences of 6.0 × 1012 and 1.5 × 1013 cm−2. However, the device exhibits performance degradation as the fluence increases to 1.0 × 1014 cm−2. As previous observations are limited to degradation. Further analysis reveals that there exist two different competitive mechanisms of neutron radiation effect on DUV LEDs. The enhancement of the output power is attributed to the increased efficiency of the carriers injected into the irradiated multi-quantum wells (MQWs). Meanwhile, neutron irradiation-induced nitrogen vacancies in p-AlGaN electron blocking layer increase the leakage of the current dominating the device performance degradation, in contrast with results from former studies on longer wavelength GaN-based LEDs. Those findings are not only helpful to further enrich the degradation mechanism of neutron irradiated DUV LEDs, but also provide a fresh idea to improve their luminous characteristics.

The last several decades have witnessed the tremendous achievement of energy storage devices such as batteries and supercapacitors in the field of charging portable electronic devices. However, the frequent charging requirement and inconvenient device replacement greatly restrict the further practical application of energy storage devices in self-powered systems for human life. Great efforts have been devoted to integrating TENG with energy storage devices to provide the sustainable power supply for electronic devices. In this review article, the recent progress of flexible TENG-based self-charging power units (SCPUs) was presented. Firstly, the working modes and triboelectric series of TENG were introduced. Next, the working principle, research progress of flexible/wearable SCPUs, and strategies to improve energy conversion efficiency were also demonstrated. Finally, the main challenges that need to be overcome when designing and optimizing TENG-based SCPUs were also highlighted.

The recently synthesized LiSbO3 with LiNbO3 structure is a new ferroelectric oxide. The elastic coefficient, electronic structure, and ferroelectric properties of LiSbO3 under different pressures are calculated by the first-principles method. The calculated results show that the mechanical and ferroelectric properties of LiSbO3 could be improved by high pressure. The calculated phonon state density and the potential energy curve of the atomic motion path indicate that the ferroelectric distortion in LiSbO3 is closely related to the interaction of Li-O atoms. At the same time, the edge position of LiSbO3 meets the conditions of photocatalytic hydrolysis to produce hydrogen. LiSbO3 is a potential, highly efficient ferroelectric photocatalytic material under ultraviolet light conditions.

Janus effect has been studied for emerging materials like Janus membranes, Janus nanoparticles, etc., and the applications including fog collection, oil/water separation, CO 2 removal and stabilization of multiphasic mixtures. However, the Janus effect on oil/water separation is still unclear. Herein, Janus Cu mesh decorated with Ni-NiO/Ni(OH) 2 core-shell nanoparticles is synthesized via selective electrodeposition, in which we keep one side of Cu mesh (Janus A) to be superhydrophilic, while manipulate the wettability of another side (Janus B) from hydrophobic to superhydrophilic. Experimental results indicate that Cu mesh with both-side superhydrophilic shows the superior oil/water separation performance (separation efficiency >99.5%), which is mainly due to its higher water capture percentage as well as larger oil intrusion pressure. Further, we demonstrate the orientation of Janus membranes for oil/water separation, and summarize that the wettability of the upper surface plays a more important role than the lower surface to achieve remarkable performance. Our work provides a clear insight of Janus effect on oil/water separation, it is significative to design high-performance membranes for oil/water separation and many other applications.

Nowadays, new emerging two-dimensional (2D) materials have become a hot topic in the field of theoretical physics, material science, and nanotechnology engineering due to their high surface area, planar structure, and quantum confinement effect. Within a two-dimensional framework, we systematically concentrate on the buckled and puckered systems consisting of the VA group elements (denoted as arsenene, antimonene, and bismuthene). Among these studied systems, the buckled antimonene harbors a thermoelectric figure of merit (ZT) of 2.15 at room temperature. This is probably the highest value that has ever been reported in pristine 2D materials. By simple biaxial strain engineering, the ZT can even get enhanced to 2.9 under 3% tensile strain. The enhancement mainly results from both tuning the electronic structures and reducing the thermal conductance. This work predicts a new promising candidate in thermoelectric devices, based on the fact that buckled antimonene has been lately fabricated and proved to be ...

High mobility, stable and thick hole-transporting layer (HTL) materials are highly desirable for organic solar cells (OSCs). In this work, two pH neutral conjugated polyelectrolytes (CPEs), namely PCPDT-T and PCPDT-2T, based on 3,4-dithia-7H-cyclopenta[a]pentalene and thienyl units with a self-doping effect were designed and synthesized. Between the two CPEs, the PCPDT-T exhibits higher, more homogeneous mobility and appropriate work function, which makes it an ideal HTL material for OSCs. The single-junction OSCs modified with the PCPDT-T HTL showed an outstanding power conversion efficiency of 9.3%, which is much higher than that of the PEDOT:PSS-modified devices (8.0%). Notably, the PCPDT-T HTL exhibits excellent thickness insensitivity in fabricating OSC devices, i.e. OSC devices with very thick PCPDT-T interlayers over 50 nm still demonstrated high power conversion efficiencies over 7.1%, which is very compatible to meet the requirement for future roll-to-roll printing.

With the rapid development of wearable devices in recent years, stretchable strain sensors based on electrically conductive composites have attracted a great deal of attention owing to their good stretchability and piezoresistivity. However, due to the intrinsic restriction of these types of composites, the conventional stretchable strain sensors cannot do well in all aspect of sensing performance. A stretchable strain sensor based on carbon nanotubes/poly(dimethylsiloxane) composite with the serpentine shape was devised and fabricated. The sensor was readily manufactured through a molding technique. Not only can this sensor distinguish tension strain from transverse or longitudinal direction, but also exhibits good linearity of response to tensile strain. In terms of sensitivity, hysteresis and response time, the stretchable strain sensor showed significant performance. The sensing performance of this proposed stretchable sensor has been demonstrated to be good in this work and it also shows a good prospect for utilization in multifunctional wearable devices.

Capacitive Deionization (CDI), a recently developed water treatment technology, has proved to be superior to traditional desalinization processes such as reverse osmosis (RO) in terms of high environmental friendliness, simple operation, and low energy consumption. This paper reviews the progress of research into CDI technology with focus on electrode materials and factors affecting CDI such as voltage and plate spacing. It also discusses existing problems and predicts the future development direction of this technology.

Based on the density functional theory, the energy band and electronic structure of β-CuGaO2 are calculated by the modified Becke-Johnson plus an on-site Coulomb U (MBJ + U) approach in this paper. The calculated results show that the band gap value of β-CuGaO2 obtained by the MBJ + U approach is close to the experimental value. The calculated results of electronic structure indicate that the main properties of the material are determined by the bond between Cu-3d and O-2p energy levels near the valence band of β-CuGaO2, while a weak anti-bond combination is formed mainly by the O-2p energy level and Ga-4s energy level near the bottom of the conduction band of β-CuGaO2. The β-CuGaO2 thin film is predicted to hold excellent photovoltaic performance by analysis of the spectroscopic limited maximum efficiency (SLME) method. At the same time, the calculated maximum photoelectric conversion efficiency of the ideal CuGaO2 solar cell is 32.4%. Relevant conclusions can expand β-CuGaO2 photovoltaic applications.

In this work, we investigate the droplet bouncing on the hierarchical branched nanotube (BNT) arrays surface above and below 0 °C. By anodization, we fabricate large-area arrays of BNT with the BNT spacing controlled from adjacent to sparse. We evaluate the influence of the BNT spacing on the droplet bouncing. The adjacently distributed BNT (A-BNT) outperforms the sparsely distributed BNT (S-BNT). We find that the A-BNT can repel up to 3.1 m/s droplet at 20 °C and 2.3 m/s droplet at −18 °C, while the maximum bouncing velocity on the S-BNT is below 2.3 m/s at 20 °C and below 0.9 m/s at −10 °C. For the bouncing on the supercooled A-BNT surface, the droplet bouncing contact time increases as the substrate temperature decreases for the same droplet velocity, while the bouncing contact time decreases as the droplet velocity increases for the same substrate temperature. We discuss the influence of the nanosized air cushion entrapped amid the branched-arms of the BNT on the three-phase contact line on the BNT walls and bouncing performance under supercooled conditions.

We studied the effect of annealing and Co ion doping on the structure, leakage current, ferroelectric polarization and magnetism of BiFeO3 samples. X-ray diffraction patterns demonstrate that an appropriate Co doping concentration is favor of suppressing the secondary phase but annealing treatment is apt to the growth of both the main and the secondary phases. The current density as a function of an electric field indicates that Co doping increases the leakage current density as samples before annealing but suppresses it after annealing. Annealing treatment improves the leakage for Co-doped sample and reduces it for the undoped sample. Ferroelectric hysteresis loops reflect that Co ions doping is liable to increase the ferroelectric polarization, while the sample is annealed it will do opposite effect. However the annealing treatment do improve the ferroelectricity for pure BiFeO3 sample. The magnetic hysteresis at room temperature shows the obvious enhancement of ferromagnetic properties with the sample after annealing.