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Imbibition is very common, occurring in life, material, chemistry, and energy. It plays an important role in enhanced oil recovery (EOR). The development of many reservoirs is beneficial to the imbibition process, such as fractured reservoirs, conventional reservoirs developed by a water-injection mode of huff-n-puff in their later development, and unconventional reservoirs with abundant micro–nanopores developed by the fracturing technology. Here, we present a critical review of EOR through imbibition. First, the mechanisms of EOR through imbibition are reviewed, including the mechanical analysis of imbibition in a capillary, imbibition models for rocks, and the scaling law. Then, the governing factors of EOR by imbibition are summarized, including the properties of rocks and fluids and the effects of the temperature and pressure. Besides, the EOR by imbibition in the oil and gas development is discussed, including the roles of surfactants, nanofluids, salinity, shut-in time, and injection/production rates. Finally, conclusions and outlooks are presented. This review provides systematic and recent insights about EOR by imbibition and a direction for future research on this topic, which can help for a better understanding of EOR by imbibition.

In this study, we aimed to demolish irregular constructions that are usually composed of convex, concave, and straight structures based on the shaped charge jet. Accordingly, the penetration behaviour of convergent, divergent, and straight linear shaped charges (LSCs) have been detected with numerical and physical methods. For comparison purposes, numerical models for all three types of LSCs with identical cross-sections have been established to investigate the impacts of structural features. It is found that the shaped charge structure not only determines the kinematic consumption during the penetration process but also influences the initial value of the jet velocity. Additionally, because of the interactions between the previous and subsequent jets, the jet velocity of the convergent LSC shows an obvious undulation during the penetration process. Furthermore, quantitative analyses of the kinematic consumption and initial velocity differences for three types of LSCs are conducted with physical models. A kinematic consumption difference is revealed, and the mass of the charge that determines the initial jet velocity as a function of the geometric parameters in three types of LSCs is deduced. Finally, we combined the numerical and physical models and conducted integral analyses to assess the penetration behaviours of the three LSC types.

In this study, the influence of different reflow profiles and dosages of SnPb solder paste on the reliability of the SnAgCu/SnPb mixed assembly process was investigated. The interfacial microstructures were carefully examined through scanning electron microscopy, and two failures modes were found. Firstly, when reflowed at 245°C for 95 s, Pb-rich phases were buried within an intermetallic compound (IMC) layer and led to micro-voids and cracks under thermal stress or mechanical stress. However, upon increasing the reflow temperature or time further led to melting the solder ball totally, and the Pb element dissolved into a liquid phase and precipitated into uniform and small granules during the cooling process. Further, among the samples with different dosages of SnPb solder paste, severe shrinkage occurred at the solder joints with the addition of 12 wt.% eutectic SnPb component. Electron back-scattered diffraction analysis was conducted in order to determine the mechanism of different shrinkages. The solder ball consisted of several primary Sn grains, and the shrinkage and Pb-rich phase are preferred to appear at the grain boundary. When the solder ball consisted of a single grain, no preferred orientation of the shrinkage and Pb-rich phase were detected. The shrinkage appeared at the final solidification region, which is near the IMC layer. Moreover, the shrinkages connect to each other, and a continuous crack formed on the chip side, leading to the failure.

In this paper, we present a new image dehazing method via fast multi-scale image fusion. It is designed based on a fusion strategy. Instead of estimating the exact global atmospheric and the transmission separately as most previous methods did, our method directly constructs initial dehazing images with different exposure through the histogram analysis and L0 gradient minimization with adaptive boundary constraint to improve the visual dehazing effect. Experimental results show that this method outperforms state-of-the-art haze removal methods in terms of both efficiency and the dehazing visual effect.

Background Docetaxel (DTX) is an anticancer drug that is currently formulated with polysorbate 80 and ethanol (50:50, v/v) in clinical use. Unfortunately, this formulation causes hypersensitivity reactions, leading to severe side-effects, which have been primarily attributed to polysorbate 80. Methods In this study, a DTX-loaded human serum albumin (HSA) nanoparticle (DTX-NP) was designed to overcome the hypersensitivity reactions that are induced by polysorbate 80. The methods of preparing the DTX-NPs have been optimized based on factors including the drug-to-HSA weight ratio, the duration of HSA incubation, and the choice of using a stabilizer. Synthesized DTX-NPs were characterized with regard to their particle diameters, drug loading capacities, and drug release kinetics. The morphology of the DTX-NPs was observed via scanning electron microscopy (SEM) and the successful preparation of DTX-NPs was confirmed via differential scanning calorimetry (DSC). The cytotoxicity and cellular uptake of DTX-NPs were investigated in the non-small cell lung cancer cell line A549 and the maximum tolerated dose (MTD) of DTX-NPs was evaluated via investigations with BALB/c mice. Results The study showed that the loading capacity and the encapsulation efficiency of DTX-NPs prepared under the optimal conditions was 11.2 wt% and 63.1 wt%, respectively and the mean diameter was less than 200 nm, resulting in higher permeability and controlled release. Similar cytotoxicity against A549 cells was exhibited by the DTX-NPs in comparison to DTX alone while higher maximum tolerated dose (MTD) with the DTX-NPs (75 mg/kg) than with DTX (30 mg/kg) was demonstrated in mice, suggesting that the DTX-NPs prepared with HSA yielded similar anti-tumor activity but were accompanied by less systemic toxicity than solvent formulated DTX. Conclusions DTX-NPs warrant further investigation and are promising candidates for clinical applications.

With the development of wireless communication technologies and explosive increases number of UEs, data traffic grows rapidly so that much denser deployment is essential. More frequent handover cause higher latency and throughput reduction, which has a negative impact on the network performance and users’ satisfaction. For the applications of 5G network including resource allocation and mobility management, it is essential to predict the positions of mobile users in the future so as to make preparation in advance. In this paper, we propose a Long Short-term Memory (LSTM) model based location prediction considering the wireless measurement reports from the serving base station and the neighbour base stations, and introduce orientation loss function in order to enable the model to acknowledge the information on the direction of the UE movement. Extensive numerical experiments demonstrated that the proposed LSTM model based on multiple features and orientation information can achieve better performance on the location prediction.

Existing dehazing methods are usually to appear visual problems. In the paper, we put forward a truncated total variation method (TTV) to eliminate haze. A histogram analysis is firstly developed to obtain global atmospheric light. Then, using an adaptive boundary constraint TTV to optimize the transmission properly. Finally, a new DCP is presented to remove haze. Shown in experimental results, our method can outperform existent methods on the visual effect.

Nanotwinned copper has excellent properties of high strength and high conductivity, making it a hot research topic in the field of electronic packaging. It is well known that additives play a crucial role during the electroplating process. And JGB is a leveler which often used in the copper electroplating industry. In our study, different concentrations of JGB were added into nanotwinned copper electrolyte in order to investigate the effect of JGB on the formation of nanotwins. It was found that the micro-morphology of nanotwinned copper is closely related to the addition of JGB during direct current (DC) electroplaitng process. The microstructural characteristics of nanotwins can be adjusted by changing the concentration of JGB. The growth rate of the film gradually slowed down when the concentration of JGB increased. What’s more, as the concentration of JGB increases, the degree of cathodic polarization becomes more and more significant, the crystals are finer, and the twinning characteristics gradually disappear.

Nanotwinned copper is reported to have excellent strength, hardness and conductivity. So nanotwinned copper is a promising material to replace conventional coarse-grain or nano-grain copper using as redistribution layer (RDL) in the electronic packaging industry. In this study, the direct current (DC) electrodeposition was used to prepare nanotwinned copper films with a high-acid and high-salt plating solution. Within these nanotwinned copper films, a 2-4 µm thick equiaxed-grain transition layer was formed between the nanotwinned region and substrate as observed by scanning electron microscope (SEM), which takes a proportion ranging from 9.7% to 46.2% of total thickness within the film. It was founded that the corresponding tensile strengths of these films is closely related to the thickness of transition layer. In detail, the smaller the proportion of the transition layer, the stronger tensile strength of the film can be obtained.

Homogeneous columnar Cu film with fully embedded nanotwins was successfully fabricated on Ti/Cu seed layer on silicon wafer. The nanotwins with thickness of tens of nanometers are generally parallel to the silicon surface, showing a strong (111) preferred orientation. The acid concentration was found to be important in influencing the formation of nanoscale twins. By adjusting the acid concentration, the nanotwins can be induced from the top columnar grain to middle columnar grain and reach the bottom equiaxed grain, and a microstructural transformation model was given. A theory focusing on the cathode overpotential was proposed to reveal the effect of acid concentration on the growth mechanism of nanoscale twins. An appropriate adsorption proportion of hydrogen on cathode (acid concentration 17 ml L−1) could increase the overpotential which supplies adequate nucleation energy for nanoscale twins formation.

Fe-Ni films with compositions of 73 wt% of Ni and 45 wt% of Ni were used as under bump metallization (UBM) in wafer level chip scale package, and their reliability was evaluated through electromigration (EM) test compared with commercial Cu UBM. For Sn3.8Ag0.7Cu(SAC)/Cu solder joints, voids had initiated at Cu cathode after 300 h and typical failures of depletion of Cu cathode and cracks were detected after 1000 h EM. While the SAC/Fe-Ni solder joints kept at a perfect condition without any failures after 1000 h EM. Moreover, the characteristic lifetime calculated by Weibull analysis for Fe-73Ni UBM (2121 h), Fe-45Ni UBM (2340 h) were both over three folds to Cu UBM’s (698 h). The failure modes for Fe-Ni solder joints varied with the different growth behavior of intermetallic compounds (IMCs), which can all be classified as the crack at the cathodic interface between solder and outer IMC layer. The atomic fluxes concerned cathode dissolution and crack initiation were analyzed. When Fe-Ni UBM was added, cathode dissolution was suppressed due to the low diffusivity of IMCs and opposite transferring direction to electron flow of Fe atoms. The smaller EM flux within solder material led a smaller vacancy flux in Fe-Ni solder joints, which can explain the delay of solder voids and cracks as well as the much longer lifetime under EM.

•Crystalline α-(Cr1-xAlx)2O3 (0.08 ≤ x ≤ 0.16) were grown on α-Al2O3 at 320 °C and 400 °C.•The films deposited at room temperature are amorphous.•The Raman and infrared vibration are dependent on the lattice constant c.•The band gap of the thin films is between 2.72 eV and 2.85 eV.

The images and videos captured in bad weather usually have low quality caused by reduced contrast and faded color. However, traditional techniques are not sufficient to solve the problems of halo artifacts and brightness distortion. In this paper, a multi-focus fusion method for single fog image restoration is proposed. Firstly, we estimate the global atmospheric light only in the sky regions to minimize interference from other regions. Secondly, we introduce a novel fast local Laplacian filtering with adaptive boundary constraint to optimize the transmission properly so as to reduce the halo artifacts. Finally, we remove the haze and produce a more natural effect on visual recovery by using a new multi-focus image fusion method. Experimental results show that the proposed method outperforms state-of-the-art haze removal methods in terms of efficiency and dehazing visual effect.

High temperature storage was conducted on SnAgCu/Fe-Ni (73 wt% Ni and 45 wt% Ni) as well as SnAgCu/Cu solder joints at 125 °C, 150 °C, and 175 °C to evaluate the diffusion barrier effect of Fe-Ni under bump metallization (UBM). For Fe-73Ni solder joints, rod-like (Cu,Ni)6Sn5 finally accumulated in the form of a continuous outer layer on the FeSn2 layer, as the aging time increased. Compared to Cu UBM, the Fe-73Ni UBM showed a better diffusion barrier effect at 125 °C and 150 °C. However, when the temperature increased to 175 °C, the inter-diffusion between FeSn2 and (Cu,Ni)6Sn5 generated a mixed IMC layer, which further transformed into the (Ni,Cu)3Sn4 phase which was accompanied with an abrupt increase of IMC thickness and rapid dissolution of UBM. In terms of the SAC/Fe-45Ni solder joints, the growth rate of (Cu,Ni)6Sn5 and the transformation of (Ni,Cu)3Sn4 were both suppressed, resulting in a compact FeSn2 layer and a higher Fe content after the UBM. As a result, the Fe-45Ni UBM showed an excellent diffusion barrier effect from 125 °C to 175 °C, as compared to the Cu and Fe-73Ni UBM. Using the statistical thicknesses of the interfacial intermetallic compounds (IMCs), the activation energies of the diffusion controlled growth of FeSn2 and (Cu,Ni)6Sn5 in Fe-45Ni solder joints were calculated as 106 kJ/mol and 122 kJ/mol, which were higher than that for the Cu3Sn (97 kJ/mol) and Cu6Sn5 (86 kJ/mol) in the Cu solder joints.

Mixed-matrix membranes (MMMs) have aroused great attention for CO2 capture due to high gas separation properties and good processability. However, besides high cost, poor interfacial compatibility and inorganic particles aggregation in MMMs hinder their further development. Herein, we chose microporous sodium zeolite-Y (NaY) as a filler, which was added into sulfonated poly (ether ether ketone) (SPEEK) to engineer the MMMs for CO2/N2 separation. We deeply studied the influence of NaY incorporation on microstructure and separation properties of the membrane. It is obvious that NaY particles were evenly distributed in the SPEEK matrix due to strong interfacial interaction by hydrogen bonding, which was verified by ATR-FTIR and SEM results, and the string-like nanochannels were formed from the SAXS observation. MMM incorporated with 20 wt% NaY exhibited the separation properties (CO2 permeability of 765 Barrer; CO2/N2 selectivity of 63) at 1 bar under the pure gas conditions, which were superior to the pristine SPEEK membrane as well as the MMMs incorporated with other zeolites, transcending the 2008 Robeson's upper bound. The enhancement in separation properties is due to the fact that CO2 molecules preferentially pass through the string-like nanochannels faster than N2 molecules under elevated relative humidity owing to selective surface flow effect. Moreover, an increase in total water of MMMs loaded with NaY also contributed to enhanced CO2 permeability, while improved CO2/N2 selectivity resulted from high bound water. More importantly, stability studies reveal that the MMM (with 20 wt% NaY loading) held outstanding CO2 separation properties for over 360 h, demonstrating outstanding stability under a gas mixture testing condition.

(0001) oriented nanocrystalline α-(Cr 1-x Al x ) 2 O 3 (0.08 ≤ x ≤ 0.16) thin films with an average thickness of ~ 270 nm were grown on c -plane α-Al 2 O 3 (0001) single crystal substrates at 400 °C by non-reactive r.f. magnetron sputtering by a combinational approach using a segmented ceramic target. The stoichiometric composition of the films was determined by electron probe micro-analysis (EPMA). The composition dependent crystallization behavior of the α-(Cr 1 − x Al x ) 2 O 3 thin films was characterized by detailed X-ray diffraction (XRD) analyses (i.e. XRD in Bragg-Brentano geometry, Rocking curve, Pole figure, Reciprocal space mapping (RSM)). Transmission electron microscopy (TEM) was carried out to study the microstructure and describe the orientation and epitaxial relationship between the films and the substrates. Further, Raman spectra show a significant shift of phonon frequency with Al concentration.

The effect of Ni element on mechanical properties of FeSn2 phase was investigated by means of nano-indentation measurements and first-principles calculations. The Ni content within (Fe,Ni)Sn2 interfacial intermetallic compounds (IMCs) were controlled by using different Fe Ni under bump metallizations (UBMs) within SnAgCu(SAC)/Fe-Ni solder joints. For SAC/Fe-45Ni (45 wt% Ni) solder joint, (Fe,Ni)Sn2 phase has coarser grains with an average amount of 1.5 at.% Ni as confirmed by scanning electron microscopy (SEM) observation and energy disperse spectroscopy (EDS). Its average Young's modulus and hardness are 134.1 GPa and 6.0 GPa respectively as measured by nano-indentation test. While for SAC/Fe-73Ni solder joints, (Fe,Ni)Sn2 phase has smaller grain size with 4.2 at.% Ni solid solution. The corresponding Young's modulus and hardness are 143.2 GPa and 6.1 GPa respectively. As further confirmed by transmission electron microscopy (TEM) and selected area electron diffraction (SAED), the (Fe,Ni)Sn2 phase possesses a crystalline of I4/mcm space group. The mechanical properties of pure FeSn2, Fe23NiSn48(about 1.5 at. % Ni) and Fe7NiSn16(about 4.2 at. % Ni) are also calculated using first principle calculation. The calculated results showed that Young's modulus increased from 134.8GPa to 139.9GPa as the Ni concentrations increased from 0 at.% to 4.2 at.%. Combining theoretical and experimental methods, we can safely conclude that the introduction of Ni element improves the Young's modulus of FeSn2 phase. However, ductility of FeSn2-based phase was the worst among the common IMCs deducing from the B/G value. And the brittleness was also confirmed by the fracture surface according to SEM observation. The brittleness of (Fe,Ni)Sn2 phase might be a risk of the reliability of SAC/Fe-Ni solder joints.

Highly discriminative feature expression for non-rigid shape recognition is an important and challenging task, which requires both abstract and robust shape descriptors. However, the majority of existing low-level descriptors are designed via hand-crafted, which are sensitive to local changes and larger deformation. To address this issue, this paper proposes a bag of shape descriptor based on unsupervised deep learning and Bag of Words (BoW) for shape recognition. Different from existing pipelines, our method is specially designed to learn high-level and hierarchical shape features from multi-scale context structures. It effectively overcomes obstacles, such as irregular topology, orientation ambiguity, and rigid or non-rigid transformation in the hierarchical learning of contour fragments. Specifically, by adopting an improved decomposing strategy, the shape can be decomposed to a series of valuable contour fragments, results in local to global feature learning. An unsupervised learning framework is also applied to the contour fragment for its feature expression based on the context structure and SSAE (Stack Sparse Auto Encode). In the process of shape representation, a high-level shape dictionary is learned by K-clustering to achieve discriminative feature coding. In addition, to achieve a compact and simplified shape representation, SPM (Spatial Pyramid Matching) is adopted by max-pooling, which effectively incorporates spatial layout information of the given shape. The experiments demonstrate that the proposed method achieves state-of-the-art performance on several public shape datasets comparing with the latest approaches. Our method also obtains high performance under the noisy and occlusion condition.

Uncertain delay differential equations (UDDEs) involving a current state and a certain past state have been proposed to model an uncertain system with a delay time, such as uncertain delay logistic model. Stability of the UDDEs is a vital problem for its applications. Based on the strong Lipschitz condition, the stability in mean for UDDEs have been investigated. Actually, the strong Lipschitz condition is assumed that it only relates to the current state, it is difficult to be employed to determine the stability in mean for the UDDEs. In this paper, we propose two kinds of new Lipschitz conditions containing the current state and the past state, which are more weaker than the strong Lipschitz condition. Meanwhile, two sufficient theorems based on these new Lipschitz conditions as the tools to judge the stability in mean for the UDDEs are verified. For a special class of the UDDEs, which are proved to be stable in mean without any limited condition. Besides, some examples are discussed in this paper.

This study was performed on the Amtrak Northeast Corridor (NEC) at Kingston, Rhode Island where is known as the Great Swamp and requires more frequent track maintenance. It was suspected that the so-called “critical speed” condition might exist at this particular location. The critical speed is the speed at which trains travel on the soft subgrade close to or higher than the Rayleigh wave velocity of the subgrade soil. The conventional understanding of the “critical speed” would expect both a cone-shaped ground wave motion and substantial amount of track deflections. Field investigations combined with a validated 3-D dynamic track-subgrade interaction model were used to evaluate the track performance and determine if the critical speed effect exists at the Kingston site. The track performance was investigated by a three-by-three (3 × 3) array of accelerometers. Site investigations were carried out to characterize the site and provide input data for modeling. According to the field measurements and model results, the rail did not show excessive deflections; however, ground surface wave propagation had been detected with a cone-shaped mode. In other words, the cone-shaped ground wave motion and the increase in rail deflection did not occur at the same time as the conventional understanding. In addition, the model results pointed out that the stress level in the subgrade would encounter a significant increase under the current operational speeds (less than 250 km/h) rather than excessive rail deflections and the rail deflections will increase dramatically at the simulated train speeds of over 300 km/h. Therefore, the “critical speed” is defined in two levels for the Kingston site: 1) The speed causing significant stress increase in the ballast and subgrade, at which more frequent ballast maintenance is needed; 2) The speed causing significant increase in rail deflection, at which derailment becomes a concern.

Thermal cycling tests have been conducted on Sn-Ag-Cu/Fe-xNi (x = 73 wt.% or 45 wt.%) and Sn-Ag-Cu/Cu solder joints according to the Joint Electron Device Engineering Council industrial standard to study their interfacial reliability under thermal stress. The interfacial intermetallic compounds formed for solder joints on Cu, Fe-73Ni, and Fe-45Ni were 4.5 μm, 1.7 μm, and 1.4 μm thick, respectively, after 3000 cycles, demonstrating excellent diffusion barrier effect of Fe-Ni under bump metallization (UBM). Also, two deformation modes, viz. solder extrusion and fatigue crack formation, were observed by scanning electron microscopy and three-dimensional x-ray microscopy. Solder extrusion dominated for solder joints on Cu, while fatigue cracks dominated for solder joints on Fe-45Ni and both modes were detected for those on Fe-73Ni. Solder joints on Fe-Ni presented inferior reliability during thermal cycling compared with those on Cu, with characteristic lifetime of 3441 h, 3190 h, and 1247 h for Cu, Fe-73Ni, and Fe-45Ni UBM, respectively. This degradation of the interfacial reliability for solder joints on Fe-Ni is attributed to the mismatch in coefficient of thermal expansion (CTE) at interconnection level. The CTE mismatch at microstructure level was also analyzed by electron backscatter diffraction for clearer identification of recrystallization-related deformation mechanisms.

A lookback option is an exotic option that allows investors to “look back” at the underlying prices occurring over the life of the option, and exercises the right at asset’s optimal point. This paper mainly investigates the lookback call and put option pricing formulas based on the uncertain exponential Ornstein–Uhlenbeck model and designs the algorithms to calculate those prices numerically. Several numerical examples are given to illustrate the effectiveness of the proposed model.

Ball shear test was conducted on the SnAgCu/Fe–Ni solder joints, as well as SnAgCu/Cu for comparison after reflow and 150 °C high temperature storage following the industrial JEDEC standards. According to microstructural observation, Fe–Ni UBMs show better diffusion barrier effect than Cu UBM, which form very thin FeSn2 or FeSn2+(Cu,Ni)6Sn5 layers at the interface without any Kirkendall voids. With such thin IMC layers, the shear strengths of Fe–Ni solder joints were comparable to Cu solder joints, which are in the range of 6.3–6.4 mg/μm2 after reflow and then fall into 4.7–5.1 mg/μm2 after 1000 h storage. Statistic observations revealed four kinds of fracture mode among failed solder joints, which are ductile fracture, brittle fracture, UBM fracture and pad lift respectively. The UBM fracture is the most common failure mode for Cu solder joint due to the fast consumption and low mechanical strength of Cu UBM, while the ductile failure takes the majority for Fe–Ni UBMs although it gradually turned into brittle fracture later as the aging time increased. The related mechanism of fracture behavior was also discussed concerning the physical properties of interfacial IMCs. Combining the low IMC growth rate, the comparable shear strength and the ductile fracture mode, Fe–45Ni UBM is superior to Cu UBM on the interfacial reliability of high temperature storage.

Three-dimensional numerical simulations and experiments were performed to examine the formation and spatial dispersion patterns of integral multiple explosively formed penetrators (MEFP) warhead with seven hemispherical liners. Numerical results had successfully described the formation process and distribution pattern of MEFP. A group of penetrators consisting of a central penetrator surrounded by 6 penetrators is formed during the formation process of MEFP and moves in the direction of aiming position. The maximum divergence angle of the surrounding penetrator group was 7.8°, and the damage area could reach 0.16 m2 at 1.2 m. The laws of perforation dispersion patterns of MEFP were also obtained through a nonlinear fitting of the perforation information on the target at different standoffs. The terminal effects of the MEFP warhead were performed on three #45 steel targets with a dimension of 160cm ( 160cm ( 1.5cm at various standoffs (60, 80, and 120 cm). The simulation results were validated through penetration experiments at different standoffs. It has shown excellent agreement between simulation and experiment results.

Crossties are critical components of the railroad track to facilitate load distribution to track substructure. Recent instrumentation at Kingston, Rhode Island indicated that a crosstie could have translations as well as rotations under train load repetitions. However, previous laboratory experiments on crossties did not fully take the crosstie rotations into consideration. In this paper, actual movements of railroad crossties under moving train loads were first characterized by numerical modeling and field investigation, and then the effect of tie rotations on track ballast performance was evaluated by discrete element modeling (DEM). A vehicle dynamics model coupled with a three-dimensional finite element track model were utilized to simulate the crosstie movements. To obtain the crosstie movements under train passage, field measurements were conducted on an Amtrak high-speed passenger line and a freight railroad short line. The measuring units were mounted on top of crossties to record the accelerations in vertical, lateral, and longitudinal directions and the Euler angles in roll, pitch and yaw. The translations of crossties were obtained by the double integration of accelerations and the rotations were represented in terms of the Euler angles. Both modeling results and field measurements indicate that crossties have not only translations but also rotations under moving trains. In addition, angular velocity and angular acceleration measured in the field tests indicate that the rotations could cause extra moments up to 5000 N-m on top of the ballast layer. The extra moments may not cause significant track failure, but may accelerate the deterioration of track components. Further, a DEM program was used to evaluate the effect of the crosstie rotations on track ballast. The results of DEM show that the crosstie rotations would increase the acceleration of individual ballast particles and contact forces between ballast particles.

Cr 2 O 3 thin films with a thickness of ~180 nm are grown on c-plane α-Al 2 O 3 (0001) single crystal substrates at a substrate temperature of 320 °C by non-reactive radio frequency magnetron sputtering. Phase formation and composition are characterized by X-ray diffraction (XRD) and Raman spectroscopy analysis. Additional information such as in-plane and out-of-plane lattice parameters, strain relaxation and texture are obtained by reciprocal space mappings (RSMs) and pole figure measurements. Transmission electron microscopy (TEM) has been carried out in order to study the microstructure and further confirm the orientation and epitaxial relationship between films and substrates.

Dividing video sequences into shots for video content analysis and video retrieval is very important, so shots are the beginning of these advanced analyses. In this paper, we proposed a new model based on visual perception, which can be expressed as "whole to local", following the concept of human vision. We first browse the video to remove the redundant frames of the video, which can reduce the computational cost. Then, the visual consistency feature of the video is used to construct the consistency function between frames to create pending shots. Finally, the shot boundary detection results are further optimized in conjunction with the motion feature. The new model which contains the inter-frame coherence and optical flow feature for shot boundary detection can shorten the calculation time and detect the shots boundary fast and accurately, without sacrificing detection performance. In terms of evaluation, the precision, recall and F1 value of the model shows good results.

To avoid halo artifacts and brightness distortion and achieve ideal visual effects, in this paper a relativity-of-Gaussian method (ROG) for single image dehazing is proposed. Firstly, we estimate the global atmospheric light only in the sky regions to minimize interference in other regions. Then, we use an adaptive boundary constraint ROG filtering to optimize the transmission properly which can reduce the halo artifacts. Finally, we remove the haze and produce a more natural visual recovery effect with an improved dark channel method. Experimental results show that this method outperforms state-of-the-art haze removal methods in terms of both efficiency and the dehazing visual effect.

An efficient three-dimensional dynamic track-subgrade interaction model has been formulated and then validated by field investigations at various field and traffic conditions including the effect of different train speeds and types of trains. The model contains a two-dimensional discrete support track model and three-dimensional computation-efficient finite element soil subgrade model. In the two-dimensional track model, the rail beam is modelled as an Euler-Bernoulli beam. The two-dimensional track model discretizes the tie and ballast as rigid bodies with designated spacing. The three-dimensional finite element subgrade model is simulated by plane-stress quadrilateral finite elements. The longitudinal direction of the subgrade model is expanded in the frequency domain and is assumed to be homogeneous. Therefore, the computing time could be largely reduced. A moving dynamic loading is applied on top of the rail. The model is capable of taking train speed variations and the profile change of the cross section into consideration. Multiple field instrumentation tests covering the two train types and different train speeds at the test site were then conducted to verify the accuracy of the dynamic track-subgrade interaction model. Testing site is located on the Amtrak's highest speed line (Northeast Corridor: 250 km/h) near Kingston, Rhode Island in the United States. A method to obtain the tie deflection from accelerometer data at Kingston was proposed and then validated at another site on the Northeast Corridor. Tie deflections measured in the field were compared with those predicted by the three-dimensional dynamic track-subgrade interaction model. It is concluded that this model can predict track performance accurately for the Kingston site.

A hanging tie is a form of railroad track distress that occurs when voids have developed beneath the ties due to uneven ballast settlement and improper maintenance practices. It will lead to an increase in dynamic impact loading on the top of the ballast thereby further deteriorating the track structure. This paper proposes a fast, nondestructive screening method to identify the hanging tie problem. The method utilizes a dynamic track model to characterize the track’s “moving deflection spectrum” under different tie-supporting scenarios. The model includes a moving dynamic load and ties with discrete supports. The moving deflection spectrum shows dynamic responses of the “track moving deflection” in the frequency domain. The modeling results indicate that a significant discrepancy exists in the moving deflection spectrum depending on whether or not there is a hanging tie condition. To validate this method, preliminary field tests were carried out on both Boston Metro and St. Louis Metro lines. Then the moving deflection spectrum generated by the model is compared with the moving deflection spectrum in the field tests as measured by the accelerometers installed on a high-rail vehicle. Results show that the method is effective in identifying the hanging tie problem and has great potential to be employed by the rail industry in the future.

In this paper, a Discrete Element Modeling (DEM) approach is used to evaluate the impacts of gradation on both ballast void space and load carrying performances. All existing ballast gradations were first represented by a set of “characteristic gradation curves”. The effect of “characteristic gradations” on aggregate assembly volumetric properties is then studied by using DEM. It is found that ballast particles with size around half of the nominal maximum size are not favorable as they separate major particle contacts and introduce extra voids i.e. decrease the overall density of the ballast. To test the effect of this particle size on ballast load carrying capability full-scale ballast layers with common gradations listed in the American Railway Engineering and Maintenance-of-Way Association (AREMA) specifications for main line railroads are generated and tested in DEM. Also, the lab test for the modeling was conducted to verify the modeling results. Repeated train loading is applied to investigate the structural performances by means of comparing settlements occurred after certain volume of traffic. Introducing ballast particles with size finer than half of the nominal maximum size was again not favorable because it yields the maximum ballast settlement. This finding is believed to provide insight into optimizing ballast layer aggregate gradations for better railroad track performances.

A series of VCN-Ag films with different Ag content were deposited by the magnetron sputtering system. The microstructure, mechanical and tribological properties of VCN-Ag films were characterized by X-ray diffractometer (XRD), Raman spectrometer, transmission electron microscopy (TEM), scanning electron microscopy (SEM), nano-indentation and ball-on disc tribo-meter. The results showed that the deposited VCN-Ag films consisted of face-centered cubic (fcc) Ag, fcc-VCN, tetragonal (t) V5CN and amorphous graphite and CNx phases, and nano-crystalline Ag was dispersed in the films. The addition of Ag below 0.72 at.% into the film increased the hardness, however, the hardness decreased rapidly when the Ag content was increased furtherly. The initial introduction of Ag into the film led to the lowering of the film's room-temperature wear rate, nonetheless, the wear resistance deteriorated when the Ag content was further increased. However, the friction coefficient of the films at room temperature increased monotonically as the content of the Ag increased. As for elevated temperature tribological properties of the film at 3.03 at.% Ag, there was an initial increase in frictional values but, when the temperature was above 300 °C the frictional values declined. More so, the wear rate increased monotonically when the temperature increased from 100 °C to 500 °C.

The interfacial reliability of Au-Si bonding between Cu/MoCu/Cu (named as CPC) substrate and silicon chip is analyzed. The results of optical microscopy (OM) and conformal laser scanning microscopy (CLSM) revealed that the Au layer of the cracked sample has small roughness without any patterns on it. Furthermore, the results of scanning electron microscopy (SEM), electron back-scattered diffraction (EBSD) and electron probe micro-analysis (EPMA) demonstrated that the void or crack initiated at the interface between a thin intermetallic compound (IMC) layer and the NiCo layer. It showed that the cracked sample had higher Ni content within NiCo layer and smaller size of Au layer. Moreover, the IMCs were characterized using transmission electron microscopy (TEM), which were identified as bulk-like dispersed NiSi2 and a thin continuous (Ni,Co)2Si layer. Based on the experimental results, the failure mechanism of Au-Si bonding is concluded coming from the unbalanced diffusion rate between Ni and Si during interfacial reaction. Higher Ni content of NiCo layer and small grain size of Au and (Ni,Co)2Si layer accelerate the diffusion of Ni, which also promotes the growth of interfacial Ni-contained IMC. As a result, the vacancy flows diffuse inversely towards the interface and form voids along the interface, which leads to the final crack failure.

Electrodeposition of Sn within porous anodic aluminum oxide (AAO) template was used to synthesize Sn nanowires. Ag seed layer was sputtered upon AAO template firstly, then the Sn nanowires were electroplated upon the seed layer. After electrodeposition the Ag seed layer was removed and the AAO template was dissolved in order to obtain Sn nanowires finally. The diameter of Sn nanowires was about 200 nm, being consistent with the template pore size, while the length of nanowires had a linear growth rate of approximately 2.49 μm/min. X-ray diffraction (XRD) and electron diffraction revealed that individual Sn nanowire was single crystal without preferential growth direction. The surface of the nanowire was wrapped by a thin SnO film (~5 nm thick), as verified by transmission electron microscopy (TEM) observation and X-ray photoelectron spectrometer (XPS) analyses. The synthesized Sn nanowire powders had a dark brown color, which comes from the surface SnO layer. Through the differential scanning calorimetry (DSC) analysis, the melting point of Sn nanowires was determined as 231.73 °C, which is about 2.7% lower than the pure Sn particles. Fabrication of Sn nanosolders from Sn nanowires was tried using liquid bath melting method. It was found that Sn nanowires could convert into spheroidal nanosolder in liquid paraffin, which demonstrated a novel technology to fabricate nanosolders used for nanoscale interconnections.

In order to investigate the performance of Fe-Ni magnetic cores within embedded inductor in 3D package, a series of Fe-Ni films with compositions ranging from 15 wt% to 80 wt% iron were electrodeposited on 8-inch silicon wafer. The uniformity on brightness, phase structure and grain size of Fe-Ni magnetic films were investigated through SEM (scanning electron microscopy) and XRD (X-ray diffraction). A gradient growth behavior of fcc (face-centered cubic) and bcc (body-centered cubic) phase was revealed when Fe content ranges 50–75 wt% within Fe-Ni films, which can be attributed to the slightly faster growth rate of fcc phase. As also revealed in TEM (transmission electron microscope) observation, the fcc phase gradually spread over bcc phase region during the electroplating process, and formed an interface with a slight tilt angle to the substrate on the thickness direction. Several methods, such as increasing solution stirring, temperature or decreasing the current density, were proposed to restrain the gradient growth behavior of Fe-Ni film in wafer level.

Uniaxial magnetic anisotropy has been induced in multi-element soft magnetic amorphous FeNiPGd thin films, which were fabricated by electroplating with an external magnetic field applied parallel to the plane of the electrode. After the application of the magnetic field, surface morphology of the FeNiPGd layer is improved. The crystal grains are refined, and the number of pores generated on the surface is remarkably reduced. The introduction of external magnetic field can significantly improve the deposition rate and dynamic permeability. And the cutoff frequency can achieve 500 MHz when the applied magnetic field is 40 mT during the deposition process. Specifically, the in-plane anisotropy field of the film was calculated by the area integral method to be approximately 116Oe while the magnetic field is 10 mT, which is obviously higher than that of the binary FeNi material.

Single image dehazing is a challenging task because of the hue and brightness distortion problems. In this paper, we propose a dual-fusion method for single image dehazing. By a segmentation method creating two divided regions, the sky and non-sky regions can be obtained. To properly optimize the transmission, a multi-region fusion method is proposed for single image smooth. An exposure fusion method is constructed by the brightness transform function to effectively remove the haze from a single image. Experimental results show that this method outperforms state-of-the-art dehazing methods in terms of both efficiency and the dehazing effect.

Haze usually degrades the visibility of outdoor images and decreases their visual quality. Previous techniques are not sufficient enough to deal with dehazing problem by using various hand-crafted priors or supervised training on paired manners. In this paper, we propose a self-constructing image fusion method for single image dehazing, which does not rely on the accuracy of global atmospheric light and transmission map. Hence, the proposed method can avoid some visual problems, such as undesirable brightness perception, unsatisfied halo artifacts and edge blur in sky regions or bright objects in dehazed images. To produce several self-constructing images with different exposures, a novel segmentation method is exploited to capture the range of global atmospheric light approximately, and a new adaptive boundary-limited L0 gradient optimization method is employed to optimize the transmission map. An adaptive selective SIFT flow multi-exposure fusion method is constructed by applying the two-layer visual sensory selector. Extensive experimental results on both synthetic and real-world images demonstrate that the proposed algorithm performs favorably against the state-of-the-art algorithms in terms of no-reference and full-reference image quality.

Cells are the most basic structural units that play vital roles in the functioning of living organisms. Analysis of the chemical composition and content of a single cell plays a vital role in ensuring precise investigations of cellular metabolism, and is a crucial aspect of lipidomic and proteomic studies. In addition, structural knowledge provides a better understanding of cell behavior as well as the cellular and subcellular mechanisms. However, single-cell analysis can be very challenging due to the very small size of each cell as well as the large variety and extremely low concentrations of substances found in individual cells. On account of its high sensitivity and selectivity, mass spectrometry holds great promise as an effective technique for single-cell analysis. Numerous mass spectrometric techniques have been developed to elucidate the molecular profiles at the cellular level, including electrospray ionization mass spectrometry (ESI-MS), secondary ion mass spectrometry (SIMS), laser-based mass spectrometry and inductively coupled plasma mass spectrometry (ICP-MS). In this review, the recent advances in single-cell analysis by mass spectrometry are summarized. The strategies of different ionization modes to achieve single-cell analysis are classified and discussed in detail.

Under-excited limiter (UEL) is one of the important auxiliary functions in generator excitation system. It has significant influence on the small signal stability of power system. However, the conventional analysis method based on Heffron-Phillips model does not consider the dynamic action of damping windings effectively. Based on the one machine infinite bus $C_{1}\sim C_{12}$ model including the damping windings, the extended $C_{1}\sim C_{15}$ model with consideration of UEL is derived. The mechanism of the system damping weaken by superimposed type of UEL is proposed based on the principle of superposition and electromagnetic torque analysis method. The results show that the electromagnetic torque provided by UEL through the main excitation channel weakens the system damping and the electromagnetic torque generated by UEL through q-axis damper winding enhances system damping. The damping torque provided by UEL reduces as the boundary line slope of UEL increases until the positive to negative. The total damping torque of the system is greatly reduced as the UEL boundary line slope increases.

With the increasing mutual interaction between smart grid and users, intelligent acquisition terminals and mobile operation terminals are widely used and accessed. The types of data transmitted in the network are more complex, and the requirements for information security protection are higher. Currently, the general security protocols for power systems do not meet the new requirements. This paper studies ISO/IEC 9798 series of standards, combines key agreement, entity authentication and hybrid algorithm technology, designs a secure channel protocol for high-security data transmission, and analyzes its complexity and time performance. Finally, it is completed based on security chip. Data transmission test shows that it has the characteristics of high security and flexible protocol, and can effectively meet the security and real-time requirements of data communication.

The captured images and videos in bad weather usually have degraded quality by reduced contrast and faded colors, and is very difficult to achieve promising performance. The traditional prior techniques are not sufficient to address this challenging problem to deal with the halo artifacts and brightness distortion problems. In this paper, we propose a multi-scale fusion method for single fog image restoration. By creating two divided regions, the global atmospheric light can be effectively obtained in the sky regions. To properly optimize the transmission, our method is designed in a new Kirsch operators with adaptive boundary constraint. With a new multi-scale image fusion method, we can effectively remove and fuse the haze from these images. The proposed method reduces the halo artifacts by adaptively limiting the boundary of an arbitrary haze image. A new multi-scale image fusion method for single image dehazing has also been proposed to produce a more nature visual recovery effect. Experimental results show that this method outperforms state-of-the-art haze removal methods in terms of both efficiency and the dehazing visual effect.

In this paper, the growth behavior of twin boundary in plated copper film was thoroughly investigated using SEM and TEM to facilitate its application as under bump metallization (UBM). The bath consisting of different amounts of H2SO4 was adopted to individually study the influence of pH on cross-sectional microstructure of copper film. Increasing the sulfuric acid concentration could greatly increase the nanoscale twin formation and make it nucleate and grow from sites much nearer the wafer. Besides, nanoscale twins were only observed in columnar grains rather than equiaxed crystallites. The growth rate of copper film was found to be enhanced with acid amount, and it was found that the stacking faults rise consequently which contributed to the nucleation and extension of the nanoscale twins. The unevenly distributed acid concentration in the bath could “recrystallize” the columnar grains into equiaxed grains, and nanoscale twins were transformed into low density of thick “annealed twins”. This could illuminate why columnar grains form ahead of equiaxed grains and coherent twin boundaries nucleated in columnar grains repetitively along the growth direction. Here, the influence of sulfuric acid was first confirmed to be the essential factor in nanoscale twin formation and this may show a distinct insight into nanotwinned copper fabrication and promote its application.

The high temperature storage test (HTST) was conducted on the SnAgCu/Ni-W-P and Ni-Fe solder joints. While the conventional Ni-P solder joints were used as comparison to study the diffusion barrier effect of Ni-W-P and Ni-Fe under bump metallization (UBM). Both cross section and top view for the microstructural evolution of solder joints during 150°C aging were observed by the scanning electron microscope (SEM). After reflow, (Cu, Ni)6Sn5 in the forms of chunky and rod-like was formed with an average thickness of around 1µm in SAC/Ni-P solder joint. During the HTST, bulky (Cu, Ni)6Sn5 grains were formed with a 5µm in diameter due to the interconnections of multiple (Cu, Ni)6Sn5 grains. In terms of SAC/Ni-Fe solder joints, during the reflow process, FeSn2 layer and rod-like (Cu, Ni)6Sn5 grains were formed. During the aging at 150°C, rod-like dispersed (Cu, Ni)6Sn5 grains started to interconnect with each other which finally progressed into an outer IMC layer upon FeSn2 phase. In Ni-W-P solder joints, the morphology and composition of IMCs is similar to it in Ni-P solder joints. The thickness of (Cu, Ni)6Sn5 was much thicker during reflow but turned out to be below it in Ni-P solder joints after 120h aging. Experimentally, both Ni-W-P and Ni-Fe UBM show an excellent diffusion barrier effect to retard the Kirkendall voids formation compared to the conventional Ni-P UBM. Specifically, (Cu, Ni)6Sn5 were formed at the SnAgCu/ Ni-W-P interface with a total thickness around 2µm, while only a 1µm thick FeSn2 layer accompanying with several dispersing (Cu, Ni)6Sn5 grains outside were formed at the SnAgCu/Ni-Fe interface. The addition of Fe elements can dramatically supress the diffusion of Ni and the formation of Ni3Sn4, which shows superior diffusion barrier compared to Ni-P UBM. The addition of W into Ni-P significantly decreases the growth rate of the interfacial IMCs during the aging process, which shows potential for electronic devices operated under long-term aging process.

Cuckoo search algorithm with advanced levy flight strategy, can greatly improve algorithm’s searching ability and increase the diversity of population. But it also has some problems. We improve them in this paper. First, in order to address the randomness of levy flight fluctuating significantly in the later and its poor convergence performance, we combine artificial bee colony algorithm with cuckoo search algorithm since artificial bee colony algorithm considers the group learning and cognitive ability, individuals learn from each other in the iterative process, which improves the local search ability of the later, and can find the optimal solution more quickly. Second, we use mutation operation to create the worst nest’s position so as to increase the diversity of the population. Then put forward the ABC-M-CS algorithm and use the thought of K-means to cluster UCI data. The experimental results on UCI data sets indicate that ABC-M-CS algorithm has the fastest convergence speed, highest accuracy and stability.

We have developed a novel nanoparticle delivery system fabricated from polyethylenimine (PEI) and poly(d,l-lactide-co-glycolide) (PLGA), which were able to deliver the chemotherapeutic agent Paclitaxel, while the biomacromolecule Herceptin acted as a targeting ligand that was conjugated onto the surfaces of the nanoparticles via electrostatic interactions. In this study, these electrostatically-conjugated Herceptin-bearing PEI/PLGA nanoparticles (eHER-PPNs) were optimized and employed as vectors to target HER2-positive breast cancer cells. The eHER-PPNs had an average diameter of ∼ 280 nm and a neutral surface charge (1.00 ± 0.73 mV), which remained stable under physiological conditions. The anticancer effects of eHER-PPNs were investigated in HER2-positive BT474 cells and HER2-negative MCF7 cells. The eHER-PPNs showed enhanced cytotoxicity that was dependent on the receptor expression levels and the incubation time. These conjugated nanoparticles deliver Paclitaxel more efficiently (p