Search

If polymer chains could be deposited on a substrate as a fully extended chain, a procedure known as "molecular combing," the chain structure could be characterized by atomic force microscopy in more detail than has been possible with the measurements available today. We show here, for the first time, that flexible polymers can be molecularly combed to fully extended chains by the dipping method. We studied the molecular combing of a series of poly(n-alkyl acrylate)s on mica from a chloroform solution by the dipping method and found that poly(n-alkyl acrylate)s with an alkyl group longer than n-octyl can be molecularly combed into straight chains under optimized conditions. With increasing alkyl lengths, the number of chains deposited decreases by four orders of magnitude, and chains become molecularly combed under a wider range of conditions. The length of the molecularly combed chains is ∼80% for poly(n-octyl acrylate) but ∼100% of the all-trans conformation for poly(n-alkyl acrylate)s with an alkyl length longer than n-nonyl.

Point load strength test is one of the indirect methods to estimate the uniaxial compressive strength of rocks. Due to its ease of sample preparation, low cost, and simple testing, it has been widely used in rock engineering in the world. The common calculation method of point load strength index is the method of equivalent core diameter of minimum cross-section, followed by the method of actual fracture section and loading distance method. However, because there are different factors being considered in different methods, the point load strength indexes obtained from different formulas varies greatly, which will result in large errors when estimating the compressive strength of rocks. In this study, a large number of point load strength tests and uniaxial compression tests were carried out using four kinds of rock samples. Then, a series of statistical analyses were conducted based on the test data. The results indicated that the distance between two loading points and the width of actual fracture section played an important and non-negligible role for failure of rock specimens, but the effect of width of minimum cross-section of specimens could be ignored. Consequently, by combing the advantages of two traditional methods, a modified calculation method of PLSI was proposed. Finally, uniaxial compressive strength of four kinds of rocks estimated by different methods was compared. The results showed that the modified method had the least estimation error.

Ceramic matrix composites (CMC) are highly required in many fields of science and engineering. However, the CMC parts always have poor surface finish. This study attempts to improve cutting performance of CMC material by combing the advantages of ultrasonic assisted cutting and diamond wire sawing. Cutting force, surface roughness, machined edge and tool wear are analyzed based on experimental results. It shows that the oscillatory movement of tool edges provides positive effect on particle ejection and residual material reduction. Ductile chip formation can be achieved due to the small tip radius of grits. Obvious decrease in cutting force, surface roughness and tool wear are obtained. Moreover, burrs, fuzzing and fracture are reduced. Meanwhile, both the surface characteristics and shape accuracy are significantly improved. These results provide a valuable basis for application of ultrasonic assisted wire sawing and understanding of CMC cutting mechanisms.

A significant challenge of surrogate model-based structural reliability analysis (SRA) is to construct an accurate approximated model of the nonlinear limit state function (LSF) with high order and high dimension effectively. As one of the sequential update-strategies of design of experiment (DoE), the active learning method is more attractive in recent years due to greatly reduces the burden of reliability analysis. Although the active learning method based on information entropy learning function H and the line simulation (AK-LS) is a powerful tool of SRA, the computational burden from the iterative algorithm is still large during the learning process. In this research, an improved learning criterion, named the weight information entropy function (WH), is developed to update the DoE of Kriging-based reliability analysis. The WH learning function consists of the information entropy function and an adaptive weight function (W). Locations in the variable space and probability densities of the samples are taken accounted into the WH learning function, which is the most important difference from the H learning function. The samples that are closer to the LSF and has a greater probability density can be preferentially selected into the DoE comparing to others by changing the weight of information entropy during the learning process. The WH learning function can efficiently match the limit state function in an important domain rather than the entire variable space. Consequently, the approximated model of LSF via Kriging interpolation can be constructed more effectively. The new active learning method is developed based on Kriging model, in which WH learning function and Monte Carlo simulation (MCS) are employed. Finally, several engineering examples with high non-linearity are analyzed. Results shown that the new method are very efficient when dealing with intractable problems of SRA.

In this paper, a novel miniaturized triple-band planar monopole antenna combing single-cell metamaterial structure and defected ground plane is proposed. The miniaturization and triple-band charact...

End milling has been widely adopted to machine the thin-plate parts that play increasingly important role in the aerospace industry, due to the advantages of high machining accuracy and fine machined surface quality. In this paper, a systematic method is proposed to predict and compensate the wall thickness errors in end milling of thin-plate parts. The errors are caused by the static deflections induced by the varying cutting force imposed on the weakly rigid part. To improve the efficiency of computing the part deformation, a novel FE model is firstly developed by combing the methods of substructure analysis, special mesh generation and structural static stiffness modification. Then, the time- and position-dependent deformations of the part are calculated based on the proposed FE model to predict the wall thickness errors left on the finished part. It reveals for the first time that the surface topography of the finished thin-plate part is formed by the repeated cutting with the bottom edge of the cutter (BEC) in end milling. Owing to the coupling between the axial cutting depth (ACD) and the force-induced deflection, the modified ACDs for compensation of the static wall thickness errors are finally determined by an iterative adjustment method. The proposed method is verified by three-axis end milling experiments. The experiment results show that the predicted wall thickness errors match well with the really measured ones, and the errors are reduced by 77.18% with the help of the proposed compensation method. Moreover, the proposed FE model reduces the computational time elapsed for error prediction by 67.44% as compared with the benchmark FE model.

Organic-inorganic hybrid coatings (OIHCs) have attracted significant attention due to their superior properties by combing both the inorganic component and the organic component together. This type...

This paper reports the results of the experimental study to substantiate the rational structural and regime parameters of a two-drum reaping machine for harvesting flax oilseeds by the method of combing plants on the root. We have confirmed the results of the preliminary mathematical modeling of the process of separating a combed heap in the reaping machine with a predefined curved shape of the casing. An experimental study of the heap separation process in a reaping machine has established the dependence of the mass fraction of the discharge of husk and stem particles from its region δh, the proportion of the release of seeds and capsules with seeds δh,and the consumed power P, on the rotation frequency of the beater-reflector n1, and the combing drum n2, the position of the air grate L and its width B. The following structural-mode parameters of the comb-type reaping machine for harvesting oil flax seeds have been defined as the most significant ones: the rotation frequency of the beater-reflector, n1=892rpm; the rotation frequency of the comb drum, n2=652rpm; the position of the air grate, L=0.62m, and its width, B=0.56m. In this case, the mass fraction of the discharge of husk and stem particles is δh=47.5%, the share of the loss of seeds and capsules with seeds from the reaping machine is, respectively, δh=2.1%, and the power consumed to perform the process is P=2.7kW. The statistical analysis has demonstrated that the correlation coefficient between the theoretical and experimental data is 0.88‒0.95; a relative error in the optimal values is 4.6%. The actual and statistical comparison of the theoretical and experimental data has confirmed the adequacy of the mathematical models built as a result of the theoretical research. Based on the results of our experimental research, one can argue about the usefulness of their application for engineering calculations when designing new technical means for harvesting crops by the method of combing plants on the root

This research work investigated the influence of carding parameters on different properties. In this study an attempt has been made to change the fibre orientation by changing the carding parameters such as feeder speed, cylinder speed and doffer speed keeping the same areal density of fabrics. In a combination of three different levels of feeder, cylinder and doffer speeds were also considered for sampling plan to create a three-factors three-levels Box-Benkhen Design for a better explanation of results. The fibre orientation was measured by using both direct (image analysis) and indirect (lindslay’s cutting and combing) method. The properties such as bursting strength, filtration efficiency and pressure drop were evaluated. The properties were analyzed and explained in the light of fibre orientation. It was found that the considered carding parameters influenced the fibre orientation to a great extent and the properties are influenced by the fibre orientation. In the end, an overall optimization has been done to achieve maximum filtration efficiency with minimum pressure drop and moderate busting strength.

This paper presents a new efficient and robust inference method by combing the robust generalized estimating equations and the well-known empirical likelihood method in longitudinal data analysis. ...

A robust sensor bias estimation approach, named as the ridge least trimmed squares (RLTS), is proposed. Combing the advantages of ridge regression and least trimmed squares, RLTS can solve the sensor bias estimation problem with the presence of misassociations and ill-conditioning. Simulation results verify the effectiveness of the proposed approach.

The intrinsic coupling effect between the multiscale microstructure and macroscopic performance is a fundamental issue in polymer engineering and polymer physics. Combing the tensile testing and in...

The only useful prior knowledge in blind compressive sensing is that a signal is sparse in an unknown dictionary. Usually, general dictionaries cannot sparsify all images well. It simultaneously optimizes the dictionary and sparse coefficient in the reconstruction process and has been demonstrated to obtain same results as those compressive sensing techniques based on the known dictionary. In this paper, we propose a novel blind compressive sensing method combing sparse and low-rank regularizations to obtain competitive recovery results. We employ truncated Schatten-p norm and lq norm to approximate rank and norm. At last, we give an optimization strategy based on alternating direction method of multipliers to solve the recovery model. Experimental results prove that our approach could obtain the higher Peak Signal to Noise Ratio values than other competitive methods.

Owing to high accuracy in the whole measurement range, the compensator-rotating method is a powerful technique for transmission/reflection ellipsometric measurements. The compensator-rotating imaging ellipsometer, which is a system combing the optical microscope and single measurement point ellipsometer, faces non-ideal measurement conditions involving nonuniformity of the retardation across the compensator. In this paper, we study the effect of non-ideal measurement conditions on the measurement noises and introduce the systematic solution.

The goal of this paper is to develop biologically inspired soft robotic hands by using cheap commercial materials. Through finite elemental analysis and material testing, this paper shows effectiveness of a soft pneumatic finger for gripping and lifting. Using ANSYS simulations, the designs were analyzed in pressures, 0.0035 MPa and 0.007 MPa. This low pressure could output high deformations of the actuators. A single finger was able to withstand 25.3 N before failure, while being able to lift 15.3 g by itself under a low voltage air pump. When combing into a claw like gripper of four fingers it was able to lift roughly 8 times that of a single finger, around 130 g. This demonstration of a functional low-cost bio-inspired pneumatic finger showcases the potential for everyday use where a delicate touch is needed. Also, the high dexterity makes it a good design for use in manufacturing or medical areas.

Purpose The purpose of this paper is to study the variation of the mechanical strength and failure modes of solder balls with reducing diameters under conditions of multiple reflows. Design/methodology/approach The solder balls with diameters from 250 to 760 µm were mounted on the copper-clad laminate by 1-5 reflows. The strength of the solder balls was tested by the single ball shear test and pull test, respectively. The failure modes of tested samples were identified by combing morphologies of fracture surfaces and force-displacement curves. The stresses were revealed and the failure explanations were assisted by the finite element analysis for the shear test of single solder ball. Findings The average strength of a smaller solder ball (e.g. 250 µm in diameter) is higher than that of a larger one (e.g. 760 µm in diameter). The strength of smaller solder balls is more highly variable with multiple reflows than larger diameters balls, where the strength increased mostly with the number of reflows. According to load-displacement curves or fracture surface morphologies, the failure modes of solder ball in the shear and pull tests can be categorized into three kinds. Originality/value The strength of solder balls will not deteriorate when the diameter of solder ball is decreased with a reflow, but a smaller solder ball has a higher failure risk after multiple reflows. The failure modes for shear and pull tests can be identified quickly by the combination of force-displacement curves and the morphologies of fracture surfaces.

Absorbent materials are considered as the most effective way of dealing with oil spill accidents and the increasing industrial oily wastewater leakages. However, poor recycling ability and low efficiency limit their application. This paper presents a fabrication approach of porous Al2O3 plates (PAP), which combines foaming and gel-tape-casting methods. The plates, which had high bending strength (4.5 ± 0.2 MPa) and oil permeation (4.4 × 105 L·m−2·h−1·bar−1), absorbed various kinds of oils rapidly, with space utilization >98%, while the absorbed oil was readily collected by simply being poured out or gas blown. Furthermore, the plate markedly maintained its high separation efficiency, mechanical strength, and hydrophobic properties after 1000 absorption-blowing cycles, as well as after treatment in several harsh environments. The results suggest that this fast and simple ceramic plate preparation approach can be proposed for practical applications in technologies of collecting oils and organic solvents from water.

Based on critical plane approach, this article develops a new damage parameter through combing the equivalent strain energy aspect for multiaxial fatigue analysis, which includes no additional fitted parameters and overcomes the deficiency of using only equivalent stress/strain criterion separately under multiaxial loadings. Then, experimental data of GH4169, TC4, Al 7050-T7451 alloys under different loading conditions are applied for model validation and comparison with other four models. Results indicate that the proposed damage parameter yields better multiaxial fatigue life predictions than others.

The identification of distributed dynamic loads is an important but challenging task because a distributed dynamic load is composed of both time and space functions. This paper proposes a n...

&nbsp, This research studied the influence of three types of open (short-straight, long-straight, semicircular) and three different shapes of closed steel fibers (triangular, rectangular, circular) with different fiber contents by volume (0, 0.5%, 1%, 1.5%, and 2%) on the working and mechanical performance of reactive powder concrete (RPC). The results indicated that (1) the number of steel fibers and the enclosed area formed by closed steel fibers would remarkably impact the performance of RPC, (2) the semicircular fiber improves RPC’s strength the most among the three open shapes, (3) the short-straight fiber works more effectively than the closed steel fibers, (4) the circular fiber works the most efficiently in improving RPC’s mechanical performance while the triangular ones have the least effect among the three closed steel fibers, (5) both the closed and open steel fibers improve their compressive strength more than their flexural strength, (6) the closed steel fiber works more efficiently in improving the flexural strength but less efficiently in improving the compressive strength, (7) the open steel fibers enhance the mechanical performance of RPC via their anchoring performance while the closed steel fibers work by confining the concrete, (8) the hybrid utilization of steel fibers improves RPC’s mechanical performance to a higher level via combing the advantages of open and closed steel fibers.

FastText is a text classification model by Facebook. As the model is simple in structure, it has the advantage of fast and efficient. However, when the model is used in Chinese text classification, the accurate rate will decrease. To this end, a Chinese FastText text classification method combing Term Frequency-Relevance Frequency (TF-RF) and improved random walk model is suggested in the paper. The method makes TF-R weight choice to N-gram processed dictionaries during the input stage of the FastText model, making semantic analysis by using Probabilistic Latent Semantic Analysis (PLSA), and supplements to feature words; then utilizes the improved random walk model to improve the accuracy, and the improved model is more suitable for Chinese text classification. The experiment result shows that improved model in the paper has a better effect to Chinese text classification.

At present, when cultivating various agricultural crops, there is an increased load of machine-tractor units on the soil horizon, due to the use of multi-operational tillage technology. The family of universal high-speed cultivators UKS of 10-, 12- and 14-meters working width simultaneously performs the following technological operations: loosening without turning the layer with cutting and combing out weeds, as well as compacting and mulching the soil surface. UKS cultivators include the following structural elements: a frame with a hitch, a hydraulic system, a disc bar, a frame consisting of the middle and side sections and wings on the transverse bars of which there are five rows of duckfoot paws, support-running wheels, and a scraper frame with seals. In the course of field research of the developed universal high-speed cultivators, it was established that their quality indicators correspond to the agrotechnical requirements: the deviation of the processing depth from the average does not exceed 1.5 cm; the presence of ridges on the surface of the field less than 3 cm high; the number of fractions less than 25 mm in size (crumbling) was more than 80%; crop and plant residues remained on the surface of the field by at least 80%.

Shared travel plays a more and more active role in the emergence of urban traffic, but there is no systematic and perfect combing and analysis on the study of bike-sharing without piles, especially on its operation and management mode. This paper will conduct a comprehensive data analysis on the research of bike-sharing without piles from the individual micro level and the enterprise government level, and explore the research focus and possible subject areas of future research.

Coal macrolithotypes control the reservoir heterogeneity, which plays a significant role in the exploration and development of coalbed methane. Traditional methods for coal macrolithotype evaluation often rely on core observation, but these techniques are non-economical and insufficient. The geophysical logging data are easily available for coalbed methane exploration, thus, it is necessary to find a relationship between core observation results and wireline logging data, and then to provide a new method to quantify coal macrolithotypes of a whole coal seam. In this study, we propose a L-Index model by combing the multiple geophysical logging data with principal component analysis, and we use the L-Index model to quantitatively evaluate the vertical and regional distributions of the macrolithotypes of No. 3 coal seam in Zhengzhuang field, southern Qinshui basin. Moreover, we also proposed a S-Index model to quantitatively evaluate the general brightness of a whole coal seam: the increase of the S-Index from 1 to 3.7, indicates decreasing brightness, i.e., from bright coal to dull coal. Finally, we discussed the relationship between S-Index and the hydro-fracturing effect. It was found that the coal seam with low S-Index values can easily form long extending fractures during hydraulic fracturing. Therefore, the lower S-Index values indicate much more favorable gas production potential in the Zhengzhuang field. This study provides a new methodology to evaluate coal macrolithotypes by using geophysical logging data.

Combing the advantages of film cooling, impingement cooling, and enhanced cooling by pin fins, laminated cooling is attracting more and more attention. This study investigates the effects of geometric and thermodynamic parameters on overall cooling effectiveness of laminated configuration, and model experiments were carried out to validate the numerical results. It is found that the increases in film cooling hole diameter and pin fin diameter both result in the increase in cooling effectiveness, but the increases in impingement hole diameter, impingement height, and spanwise hole pitch degrade the cooling performance. The increase of the coolant flow rate causes the increase in cooling efficiency, but this effect becomes weaker at a high coolant flow rate. The coolant-to-mainstream density ratio has no obvious effect on cooling effectiveness but affects wall temperature obviously. Moreover, based on the numerical results, an empirical correlation is developed to predict the overall cooling efficiency in a specific range, and a genetic algorithm is applied to determine the empirical parameters. Compared with the numerical results, the mean prediction error (relative value) of the correlation can reach 8.3%.

To widen bridges, a usual method is to cast joint connections between new and old bridge decks without traffic interruption. The traffic vibrations have negative influence on the quality of joint connections. Shortening the construction time can alleviate the impact on the traffics, a fast-hardening retarding high-early-strength concrete (FRHC) for the connections is in need. In this study, low-alkalinity sulphoaluminate cement (LASC) concrete was modified to gain these characteristics. Based on FRHC concrete, four slab specimens including a monolithic concrete slab and three joint FRHC slabs were cast to investigate their flexural behaviors. With proper splicing details in joint connections, the joint FRHC specimens behaved approximately similar to the monolithic specimen. Combing the laboratory tests and engineering practice, the newly developed FRHC mixture succeeded in fast-hardening, retarding and high-early strength and the joint connections filled with FRHC have a good flexural performance.

A compact circular-polarization discriminator is presented in this paper. The proposed structure is composed of three simple layers, which are connected by air spacers. The first and third layers act as circular polarisers (CPs), and the second one is a linear polarizer (LP). By combing the three layers together, the right-handed circularly-polarized wave (RHCPW) can be reflected, while the left-handed circularly-polarized wave (LHCPW) can be transmitted through the proposed structure. Within the operating band, the insertion loss is lower than 2.5 dB. Finally, the proposed design is validated by both simulated and measured results.

Graphs and graph-processing have become increasingly important. This has led to an explosion in the development of graph-processing systems, each of which is evaluated relative to its predecessors. In the absence of a large corpus of real-world graphs, synthetic generators provide an easy way to construct graphs of varying sizes. The most widely used generator is the Kronecker generator. Unfortunately, the Kronecker generator was not designed to produce graphs for benchmarking and when used in this fashion, it is problematic in two ways. First, the fraction of zero-degree vertices scales with the graph size, dramatically reducing the effective size of the connected graph. Second, the generator produces a vertex degree distribution not found in real world settings. We demonstrate these phenomena and present the Smooth Kronecker Generator, which remedies the vertex degree distribution problem without changing the statistical properties of the graph.

In this study, we introduce a data stream method for dynamic runoff simulation, which allows capturing the evolving relationship between runoff and its impact factors (e.g., temperature, rainfall). The basic idea is to view continuously arriving data of runoff and its impact factors as a data stream, and dynamically learn its relationship. To validate the effectiveness of the proposed method, we compare its performance with that of three data driven models (ANN, SVR, Random Forest) and six representative hydrological models (SWAT, AWBM, SimHyd, SMAR, Sacramento, and Tank) in simulating monthly runoff. The proposed method performs well with the best NSE of 0.88, being superior to comparable models. Furthermore, the data stream model also shows its advantage in the flexibility of combing various impact factors of runoff into the model. The findings demonstrate that the data stream method provides a promising way to dynamically simulate runoff in a changing environment.

Kansei Engineering (KE) is a user-oriented technology combing customer psychological feelings and engineering for designing and developing products. Conventionally, questionnaire surveys have been ...

The artificial bee colony (ABC) algorithm, which has been widely studied for years, is a stochastic algorithm for solving global optimization problems. Taking advantage of the information of a global best solution, the Gbest-guided artificial bee colony (GABC) algorithm goes further by modifying the solution search equation. However, the coefficient in its equation is based only on a numerical test and is not suitable for all problems. Therefore, we propose a novel algorithm named the Gbest-guided ABC algorithm with gradient information (GABCG) to make up for its weakness. Without coefficient factors, a new solution search equation based on variable gradients is established. Besides, the gradients are also applied to differentiate the priority of different variables and enhance the judgment of abandoned solutions. Extensive experiments are conducted on a set of benchmark functions with the GABCG algorithm. The results demonstrate that the GABCG algorithm is more effective than the traditional ABC algorithm and the GABC algorithm, especially in the latter stages of the evolution.

An accurate battery state-of-health (SOH) monitoring is crucial to guarantee safe and reliable operation of electric vehicles (EVs). In this paper, an incremental capacity analysis (ICA) method for battery SOH estimation is proposed. This uses grey relational analysis in combination with the entropy weight method. First, an interpolation method is employed to obtain incremental capacity (IC) curves. The health indexes are then extracted from the partial IC curves for grey relational analysis, and the entropy weight method is used to evaluate the significance of each health index. The battery SOH is assessed by calculating the grey relational degree between the reference and comparative sequences. Experimental tests are conducted on two battery cells with the same specifications to verify the efficacy of the proposed method. The results show that the maximum estimation error is limited to within 4%, thus proving its effectiveness.

Based on critical plane approach, this paper develops a new damage parameter through combing the equivalent strain energy aspect for multiaxial fatigue analysis, which includes no additional parameters and overcomes the deficiency of using only equivalent stress/strain criterion separately under multiaxial loadings. Then, experimental data of GH4169, TC4, Al 7050-T7451 alloys under different loading conditions are applied for model validation and comparison with the other four models. Results indicate that the proposed damage parameter yields better multiaxial fatigue life predictions than others.

Facility layout and production planning, as two important phases during flexible production mode, have a significant effect on production efficiency and cost with the changing of consumer demand. Motivated by the problem, considering the integration between facility layout and production planning, this paper develops the model of flexible production process based on the Petri Net. The serial optimization approach combing reachability graph algorithm and search algorithm is designed to work out the problem. Then the flexible production planning and dynamic layout scheme are obtained sequentially. Finally, a case study is carried out to verify the validity and performance of the methodology.

Based on the structural features of aluminum foam sandwich (AFS) panels, random two-dimensional models of AFS panels are established by combing C++ and ANSYS/LS-DYNA in this work. During the compression process, the simulation studies on energy absorption property of AFS panels are conducted through the orthogonal experiment, range analysis and variance analysis. Four variables including porosity P, cell radius R, loading rate V and thickness of aluminum foam core H have been considered in the above research. The results indicate that for the energy absorption property of AFS panels, the influence of these variables from high to low in order is: porosity, cell radius, loading rate, thickness of aluminum foam core. Moreover, the combination of the optimal absorbed energy of AFS panels is P1R1V4H4. In addition, the obtained results also show that the absorbed energy by AFS panels decreases with the increase in the porosity or cell radius, but increases gradually under a higher loading rate. Meanwhile, the influence of parameter H on the energy absorption of AFS panels is not found.

Bacteria can easily colonize on the biomaterials surface which leads to biofilm formation and serious bacterial infections. In this work, a new raspberry structured core-shell nanoparticles were developed through two-step emulsion polymerization method. Robust superhydrophobic film formed on the substrate showed both high efficient self-cleaning and bactericidal properties.

Many drilling and oil companies are facing tight budgets, and a promising option for survival is to optimally revisit the drilling plans and production operations. Although there are some options f...

This paper investigates the leader-following fixed-time output feedback consensus problem for second-order multi-agent systems with input saturation. By combing fixed-time control technique and bi-...

Artificially embedded surface charges can dramatically improve the output energy of water–solid contact electrification devices, but the embedded charges easily escape or are cancelled out by adsorption of opponent ions in ambient conditions. Here, we demonstrate a hybrid energy harvesting nanogenerator by combing water–solid and solid–solid contact electrification schemes. It consists of a water–solid contact electrification device and wind-fluttering ribbons that regularly supplies triboelectric surface charges on the solid surface and hence, the high density of surface charges can remain on the surface. This scheme can enhance the harvesting energy by up to a factor of 30 during rain. Moreover, the fluttering ribbons independently collect electric energy from mild winds without rain. This scheme provides a facile, cost-effective, and robust approach to enhance the energy-harvesting efficiency of a water–solid contact electrification device and to combine the energy harvesting from simultaneous rain and wind.

The relation between flow instability and friction pressure drop of flow boiling in multichannel was investigated by visualization experiments and theoretical analysis. Based on visualization observation, both slug flow and liquid-plug flow were the dominating flow patterns for all operation conditions, and combing with flow instability simultaneous. With theoretical analysis, the vapor slug extension growth velocity would affect the shear force which was the main reason for friction pressure drop. In addition, the channels number and the channel length had significant effects on flow instability. With the simplified vapor growth model and the analysis on the collected database statistically, the modified friction factor, finter, and the structure factor, fstr, were proposed for the revised homogenous friction pressure drop correlation. By comparing with the database, the modified pressure drop correlation predicted the collected experimental data in a good agreement.

In this paper, a new Si3N4-based graded ceramic tool was prepared by hot press technology The tool was toughened by microscale (W, Ti)C, nanoscale Si3N4, and metal Co. The graded structure combing with proper composition distribution introduced thermal residual compressive stress into the surface layer of the tool according to the FEM analysis. The performance of the tool in high-speed intermittent turning GH2132 alloy (equivalent to A286) was studied in contrast to one homogeneous tool. The cutting forces analysis indicates that the inserts endure periodic mechanical shock in the intermittent cutting process and the mechanical shock is more serious when the tooth engages the workpiece than when it disengages the workpiece. The tool failure modes observation shows ladder-like fracture under thermal and mechanical shock in the intermittent cutting process. Tool failure mechanisms involve chipping, flaking, microcracks, and adhesion. The graded tool shows better thermal and mechanical shock resistance than the homogeneous tool due to the formation of residual compressive stress.

Classification and well-logging evaluation of carbonate reservoir rock is very difficult. On one side, there are many reservoir pore spaces developed in carbonate reservoirs, including large karst caves, dissolved pores, fractures, intergranular dissolved pores, intragranular dissolved pores, and micropores. On the other side, conventional well-logging response characteristics of the various pore systems can be similar, making it difficult to identify the type of pore systems. We have developed a new reservoir rock-type characterization workflow. First, outcrop observations, cores, well logs, and multiscale data were used to clarify the carbonate reservoir types in the Ordovician carbonates of the Tahe Oilfield. Three reservoir rock types were divided based on outcrop, core observation, and thin section analysis. Microscopic and macroscopic characteristics of various rock types and their corresponding well-log responses were evaluated. Second, conventional well-log data were decomposed into multiple band sets of intrinsic mode functions using empirical mode decomposition method. The energy entropy of each log curve was then investigated. Based on the decomposition results, the characteristics of each reservoir type were summarized. Finally, by using the Fisher discriminant, the rock types of the carbonate reservoirs could be identified reliably. Comparing with conventional rock type identification methods based on conventional well-log responses only, the new workflow proposed in this paper can effectively cluster data within each rock types and increase the accuracy of reservoir type-based hydrocarbon production prediction. The workflow was applied to 213 reservoir intervals from 146 wells in the Tahe Oilfield. The results can improve the accuracy of oil-production interval prediction using well logs over conventional methods.

To access highly ion-conductive membrane materials which are urgently desired by the technologies like fuel cells, flow batteries, electro-dialysis etc., a novel polymer architecture featured by the densely grafting of three ionic strings onto each benzene ring was developed. Compared with the previous densely functionalized AEMs prepared by closely attaching multiple cations onto polymer main chain, this study aims to achieve the improved nano-phase separation ability through combing the advantages of high cation mobility and high cation density. As a result, distinct ion conducting channels were observed by atomic force microscopy and high Br- conductivity of 50.6 mS/cm was achieved at 80 °C, suggesting the effectiveness of this strategy.

A nonlinear visco-elastic–plastic creep constitutive model is established combined with a Bingham creep model and a Kelvin creep model. Additionally, the soil creep parameters of an undisturbed soil specimen from the Wuxi subway engineering investigation site are determined according to triaxial creep testing using the ordinary least square algorithm. The ground characteristic curves considering the time effect are proposed by combing the creep equation and cavity expansion theory. Finally, the change laws of segment support force and segment deformation as a function of time were investigated through a case study of a section of the Wuxi Subway Line No. 1, and the proposed analytical solution and numerical modeling provide consistent results for tunnel lining pressure.

In order to optimise the construction of soft body armour panels by hybridization, this study aims to identify materials determination for hybrid panel. Different ballistic characteristics of aramid woven fabrics and Ultra High Molecular Weight Polyethylene uni-directional laminates were investigated through ballistic test and fractorgaphic analysis. With an increasing of total layer numbers in a panel, specific energy absorption of Twaron woven panel shows a decrease trend, and Dyneema UD panel exhibits an increasing trend. Such reverse trend of ballistic performance is due to different failure modes of two materials. According to fractorgraphic analysis, Twaron fabric has large transverse deformation for back layers in a perforated panel. This results in higher energy absorption in back layers. For Dyneema UD, thermal damage is the dominant failure mode, which can result in performance degradation especially for front layers on the strike face. In addition, Dyneema UD exhibits significant advantage of minimize Backface Signature (BFS) and a little higher perforation ratio than that of Twaron woven panels. Based on these findings, an optimized hybrid panel is designed by combing Twaron woven fabric before Dyneema UD. In comparison with other panels with different layer sequences, this hybridization manner exhibited better ballistic performance, including improvement of energy absorption, minimized BFS of the non-perforated panel and reduction of perforation ratio. These findings indicated that material determination for hybrid design should be based on ballistic characteristics of different materials and requirements of different regions in a panel.

Graphene-on-semiconductor has been proved to be a quality heterojunction with efficient photoelectric conversion. In this work, we constructed Schottky junction solar cells by combing graphene woven fabrics (GWFs) and n-doped single crystal silicon, and examined the performance of solar cells when GWFs of different meshes were used. Sparse GWFs possessed high optical transparency but led to poor carrier collection, whereas dense GWFs could collect carriers efficiently but generated too few photo carriers due to low transparency. The GWFs with an optimal mesh could provide a good balance between the generation and collection of photo-induced carriers to deliver high power conversion efficiency. Keywords: Graphene, Heterojunction, Solar cell

A thermo-elastic-plastic numerical method based on the hybrid inversion combing experiment results and numerical results was developed. The influence of various factors in the welding process on the welding deformation and residual stress was taken into account through the equivalent heat source parameter (EHSP). The out-of-plane displacement and residual stress of the butt-welded plate were measured firstly with electrical measurement method and hole-drilling method respectively. Then, a function was established to evaluate the standard error (SE) employing different heat source parameters between numerical and experimental results, and the EHSP corresponding to SEmin for the current material and welding conditions was inversed. At last, the EHSP was applied to the investigation of welding sequence. This method is also suitable for other welding methods and weld types.

It is inevitable to excavate slide slope and damage rock slope under the rapid development of expressway. To further remedy ecological environment, correct understanding of side slope stability is essential for the effective reinforcement and protection of rock–soil slope. In this paper, the reinforcement and protection technologies of cutting slopes were introduced firstly, and then the classifications of rock–soil slope reinforcement technologies in China and abroad were compared. Taking the Daqing–Guangzhou Highway as the research subject, three kinds of reinforcement and protection schemes were proposed and analyzed. Combing fuzzy comprehensive judgment with analytic hierarchy process, a supporting model of cutting slopes was established. The analytic hierarchy process was used to determine the weight and the degree of membership was calculated. Finally, the model was applied into the project to carry out evaluation. The results showed that the fuzzy comprehensive evaluation model used in this paper had a good reference value for the future development of cutting slopes.

At present, in the field of management science research, traditional analysis methods can’t meet further research needs, so the cross layer analysis method is getting more and more attention from researchers. Cross layer analysis can effectively identify the role and influence of variables of different levels. This paper demonstrates the cross layer analysis method and through combing process logic, explaining deep problems in management science.

Spectral method based on Fast Fourier Transforms (FFT) is developed to study the mechanical properties of three-dimensional (3D) braided composites with complex internal microstructures. The FFT-based method can calculate the material properties by directly using real microstructure images, which could avoid conformal meshing geometry and assembling stiffness matrix similar as FEM. Combing with damage model, the FFT-based method is used to study the progressive damage of the braided composites. The strength and dominated failure modes of the braided composites obtained by the FFT-based method are also verified by the experimental results. Due to the high computation efficiency, the FFT-based method also has a great potential to be used in multi-scale computation analysis for textile composites.