Search

Background: Fractures heal through a process that involves angiogenesis and osteogenesis but may also lead to non-union or delayed healing. Bone marrow mesenchymal stem cells (BMSCs) have been reported to play a pivotal role in bone formation and vascular regeneration and the p75 neurotrophin receptor (p75NTR) as being an important regulator of osteogenesis. Herein, we aim to determine the potential mediation of BMSCs by p75NTR in bone healing. Methods: Rat BMSCs were identified by flow cytometry (FCM) to detect cell cycle and surface markers. Then transfection of si/oe-p75NTR was performed in BMSCs, followed by Alizarin red staining to detect osteogenic differentiation of cells, immunofluorescence double staining was performed to detect the expression of p75NTR and sortilin, co-immunoprecipitation (CO-IP) was conducted to analyze the interaction between p75NTR and sortilin, and EdU staining and cell scratch assay to assess the proliferation and migration of human umbilical vein endothelial cells (HUVECs). The expression of HIF-1α, VEGF, and apoptosis-related proteins were also detected. In addition, a rat fracture healing model was constructed, and BMSCs-si-p75NTR were injected, following which the fracture condition was observed using micro-CT imaging, and the expression of platelet/endothelial cell adhesion molecule-1 (CD31) was assessed. Results: The results showed that BMSCs were successfully isolated, p75NTR inhibited apoptosis and the osteogenic differentiation of BMSCs, while si-p75NTR led to a decrease in sortilin expression in BMSCs, increased proliferation and migration in HUVECs, and upregulation of HIF-1α and VEGF expression. In addition, an interaction was observed between p75NTR and sortilin. The knockdown of p75NTR was found to reduce the severity of fracture in rats and increase the expression of CD31 and osteogenesis-related proteins. Conclusion: Silencing p75NTR effectively modulates BMSCs to promote osteogenic differentiation and angiogenesis, offering a novel perspective for improving fracture healing. [ABSTRACT FROM AUTHOR]

Aiming to the problem that thermal error seriously weakens grinding accuracy, according to the involute property and involute helical gear form-grinding principle, this work proposes a novel thermal error predicting model with the combination of steady-state temperature field working condition and non-steady-state temperature field working condition to optimize machining accuracy, eliminate warm-up time, and improve processing efficiency. In view of the above, the independently developed new type of high-precision horizontal forming CNC gear grinder L300G is taken as research object, and the combination of fuzzy clustering algorithm and mutual information theory is taken to optimize temperature variables, which is also verified with the comprehensive gray correlation; on this basis, L300G thermal error predicting model is established based on the combination of autoregressive time series and BP neural network. Then, the model is given practice tests through temperature field finite element analysis, temperature and thermal error measuring, temperature variables optimizing, thermal error predicting, and involute helical gear form-grinding. Results show that the model is fairly effective in thermal error predicting; what is more, after thermal error real-time compensation, it can eliminate warm-up time of gear grinder about 6000 s, and the Gleason measuring results show that the involute helical gear form-grinding tooth profile accuracy is improved from level 6 to 4, which verifies the correctness. So that it is expected to be widely used in high-precision form-grinding of horizontal gear grinder; besides, it also has significance for high-precision form-grinding research of vertical gear grinder. [ABSTRACT FROM AUTHOR]

The influence and mechanism of porous structure on the deformation failure of cement sheaths under hydraulic pressure is still unclear. To solve this problem, a net slurry cement sheath and a liquid silicon cement sheath were prepared by using a cement material and a liquid silicon suspension. The distributions of the pore radius and spatial location were analyzed using computed tomography scanning and statistics to obtain their probability density distribution functions. Based on the distribution functions, the single-layer and double-layer porous reconstruction models of the net slurry cement sheath and liquid silicon cement sheath were constructed using a FLAC 3D program. A series of numerical simulations were conducted to study the deformation failure of the cement sheaths under in situ stress and hydraulic pressure. The effects of the porous and double-layer structures on the breakdown pressure, plastic failure zone, radial deformation, and stress distribution of the cement sheaths were analyzed. As a result, the mechanisms for the influence of the porous and double-layer structures on the failure mode, failure path, and interaction between the cement sheath and metal casing were revealed. The results of this research provide a theoretical basis for an in-depth understanding of the failure mechanisms of porous cement sheaths. [ABSTRACT FROM AUTHOR]

For instance, by employing a tripodal bis(benzimidazole) ligand bis((1-methylbenzimidazol-2-yl)methyl)amine(MeIDB) and its derivative as the main ligand, a series of nickel and copper complexes were synthesized which allow a systematic investigation of a biomimetic chemistry [[8]]. Comment Multi-benzimidazole ligands have been often used in the synthesis of various metal-organic complexes or modelling the biomimetic coordination environment around the enzymatic active site [[7]]. However, up to now the detailed crystallization properties of MeIDB has been not reported which can be helpful for the design of various multifunctional compounds due to its central acyclic -CH SB 2 sb -N-CH SB 2 sb - linkage moiety, making the ligand possess various steric arrangements. [Extracted from the article]

Deterioration of adhesively bonded CFRP/steel systems in salt fog environment, i.e., deicing salts and ocean environments, has to be taken into account in the design of steel strengthened structures. In the present work, monotonic and quasi-static cyclic loading were applied to CFRP-to-steel double strap joints for two kinds of CFRP laminates after being aged for a period of 5000 h to evaluate the bond behavior. The bonded joints exposed to salt fog had a different failure mode than that observed in the control specimens (0 h of exposure). The severe reduction of the maximum bond stress resulted from damage initiation that occurred in the corrosion region of the steel substrate, associated with final partial rupture on the corroded steel substrate around the edge of the bonded area: it was also correlated with reduced load carrying capacity. Results of pseudo-cyclic tests showed that the relationship between a local damage parameter (D) and normalized local dissipated energy (W d /G f) and the normalized slip increment (ΔS/ΔS ult) exhibited almost the same trend in the un-aged and aged bonded joints. The normalized slip increment can be seen as a direct indicator for the local and global damage for the un-aged and aged bonded joints. However, monotonic and quasi-static cyclic tests results revealed that the stress concentration due to local corrosion of steel substrate could lead to brittle rupture or accelerated cumulative damage once the aged bonded interface had become weaker. The bonded joints have exhibited also a smaller relative deformation capacity between CFRP and steel. [ABSTRACT FROM AUTHOR]

The bearing vibration of wind turbines is nonlinear and non-stationary. To effectively extract bearing vibration signal features for fault diagnosis, a method of feature vector extraction based on variational mode decomposition (VMD) and energy entropy is proposed. In addition, the support vector machine (SVM) classifier is used to identify the types of vibration faults. VMD transforms the constrained variational objective function into the unconstrained one to optimize solution. Compared with the VMD and empirical mode decomposition (EMD), the modal decomposition layer of VMD is less than EMD, no found false modality, and truly reflecting signal components. After the Hilbert transformation, double logarithmic coordinates show that the VMD-based spectral characteristics are significant. VMD is performed on the different types of vibration signals of wind turbines. Therefore, VMD is not that affected by noise and has few decomposition levels. The energy entropy of the normalized four modal components is considered the eigenvalue and classified by SVM, and compared with EMD-based and wavelet db4-based energy entropy eigenvalue extraction methods. Experimental results indicate that the accuracy of the method is higher than those based on EMD and wavelet db4, under the limited sample condition. Thus, a referential diagnostic method is provided for practical applications. • A method of feature vector extraction based on variational mode decomposition (VMD) and energy entropy is proposed. • The time-frequency energy spectrum obtained by VMD is compared with that by empirical mode decomposition (EMD). • Different types of bearing vibration signals of wind turbine are analyzed. • The fault diagnostic identification of the proposed method is compared with EMD-based and wavelet db4-based methods. [ABSTRACT FROM AUTHOR]

Abstract The degradation mechanisms of bonded joints between CFRP laminates and steel substrates under severe environmental conditions require more durability data and studies to increase the database and better understand their causes. Studies on bond properties of double-strap CFRP-to-steel bonded joints with two different composite materials as well as adhesive coupons subjected to freeze-thaw cycles for 10,000 h were conducted to reduce that gap. In addition, the equivalent to the number of thermal cycles and their slips induced in the CFRP laminates was replicated by an equivalent (mechanical) loading-unloading history condition imposed by a static tensile machine. The mechanical properties of the adhesive coupons and the strength capacity of the bonded joints were only slightly changed by the artificial aging. It was confirmed that the interfacial bond strength between CFRP and adhesive is critically related to the maximum shear stress and failure mode. The interfacial bond strength between adhesive and steel degraded with the aging. However, the equivalent thermal cyclic bond stress caused no detectable damage on the bond because only the interfacial elastic regime was actually mobilized, which confirmed that pure thermal cycles aging, per se , at the level imposed, have a low impact on the degradation of CFRP-to-steel bonded joints. [ABSTRACT FROM AUTHOR]

Pseudo-cyclic and cyclic loading were applied to CFRP-to-steel bonded joints built with two different CFRP laminates. In this paper, the strength capacity and bond-slip curves are presented and compared. The modes of failure are also described and associated with the types of material used, and the observed performances are correlated. The analysis of the results showed a threshold value for loading and amplitude level, below which the cyclic loading caused no detectable damage. For cycles above that limit, the region of the joints around the loaded end presented degradation reflected on the bond-slip stiffness and on the increase of residual deformation. It was found that the normalized dissipated energies either obtained from the bond-slip relationship or from the load-slip response had the same trend. The experimental data allowed also to establish a relationship between the damage developed within the interface and the normalized slip. A preliminary estimate of fatigue limit based on those data is suggested. [ABSTRACT FROM AUTHOR]

Lumen is a common anatomical condition in endoscopic therapy or diagnostics. The navigation of autonomous robotic endoscopy usually involves vision techniques such as detection of lumen center or anatomically specific contour features. However, these methods may fail to achieve smooth interventions and result in large conveying force without spatial awareness of the tissue state. In this paper, a novel navigation pipeline based on a spatial-aware monocular vision is proposed. The spatial awareness pipeline starts with a data-driven depth estimation technique for reconstructing real-time approximate tissue surface. The spatial shape of the lumen described by the skeleton is then extracted using digital topology. We modify the skeleton to get a smooth pathway, and design an adaptive autonomous control strategy using geometric information from the pathway. We conduct experiments on a colon phantom and ex vivo pig intestines. We test turning performance of several bending segments with different angles in phantom, as well as the overall performance of a long-range intervention task in the phantom and pig intestines. The results show our navigation scheme achieve smoother intervention with lower conveying force. The proposed navigation method with spatial awareness can effectively improve the fluency of autonomous robotic endoscopy. • Use explicit and implicit geometric consistency for endoscopic depth estimation. • Extract spatial pathway from depth map by digital topology method. • Utilize spatial information in adaptive control of autonomous robotic endoscopy. • Test autonomous endoscopy on digestive tract phantom and ex vivo pig intestines. [ABSTRACT FROM AUTHOR]

Monocular depth estimation is critical for endoscopists to perform spatial perception and 3D navigation of surgical sites. However, most of the existing methods ignore the important geometric structural consistency, which inevitably leads to performance degradation and distortion of 3D reconstruction. To address this issue, we introduce a gradient loss to penalize edge fluctuations ambiguous around stepped edge structures and a normal loss to explicitly express the sensitivity to frequently small structures, and propose a geometric consistency loss to spreads the spatial information across the sample grids to constrain the global geometric anatomy structures. In addition, we develop a synthetic RGB-Depth dataset that captures the anatomical structures under reflections and illumination variations. The proposed method is extensively validated across different datasets and clinical images and achieves mean RMSE values of 0.066 (stomach), 0.029 (small intestine), and 0.139 (colon) on the EndoSLAM dataset. The generalizability of the proposed method achieves mean RMSE values of 12.604 (T1-L1), 9.930 (T2-L2), and 13.893 (T3-L3) on the ColonDepth dataset. The experimental results show that our method exceeds previous state-of-the-art competitors and generates more consistent depth maps and reasonable anatomical structures. The quality of intraoperative 3D structure perception from endoscopic videos of the proposed method meets the accuracy requirements of video-CT registration algorithms for endoscopic navigation. The dataset and the source code will be available at https://github.com/YYM-SIA/LINGMI-MR. [ABSTRACT FROM AUTHOR]

Highlights • We propose a robust one-shot three-dimensional imaging method based on image processing. • We propose a top to bottom clustering algorithm to cluster the continuous lines robustly. • We propose a phase map computation method based on the clustered lines. Abstract Reconstruction of the object by single-shot is of great importance in many applications, in which the object is moving or its shape is non-rigid and changes irregularly. In this paper, we propose a single-shot structured light 3D imaging technique that calculates the phase map from the distorted line pattern. This technique makes use of the image processing techniques to segment and cluster the projected structured light line pattern from one single captured image. The coordinates of the clustered lines are extracted to form a low-resolution phase matrix which is then transformed to full-resolution phase map by spline interpolation. The 3D shape of the object is computed from the full-resolution phase map and the 2D camera coordinates. Experimental results show that the proposed method was able to reconstruct the three-dimensional shape of the object robustly from one single image. [ABSTRACT FROM AUTHOR]

Transformer is an important equipment for power energy transmission. The vibration and noise of transformer have always been a serious issue of people concern. Transformer body vibration and noise are mainly caused by the global magnetization of limbs and yokes and magnetic forces of transformer core. However, the process of vibration transfer from core to body is a key factor for monitoring the transformer condition. In this paper, a transformer model for vibration transmission is presented based on motion transmission and it can be used to analyze the vibration relation between core and shell of transformer. Considering strain of silicon steel as the vibration source, the motion equations whichexpress the relations of transformer core and shell are derived. And then, the test system is built to analyze the vibrations of a 5 kVA three phase transformer. A 3D real model simulation used COMSOL finite element software is performed for analyzing the deformation characteristic of transformer. The locations of test points which reflect the vibration more efficiently are determined through the deformation simulation results. Lastly, the vibration signals of two directions have been measured considering DC magnetic bias or not. The experimental results reveal that vibration relations between core and shell are satisfied with the theoretical derivation. Therefore, the Vibration Transmission is significant and it can provide valid method for the DC magnetic bias analysis and core diagnosis of transformer. [ABSTRACT FROM AUTHOR]

Partial discharge (PD) is one of the main diagnosis methods for the insulation aging of large motors. A data compression denoising method based on the empirical mode decomposition (EMD) algorithm is proposed according to the weak and large disturbances of large motor PD signals. A simulation model is constructed to verify the effectiveness of the proposed algorithm. Furthermore, the denoising effect of the proposed algorithm is compared with that of the db2 and db8 wavelets in the experiments. The simulation and experimental results show that a data compression denoising algorithm based on EMD can achieve the same denoising effect with those based on db2 and db8 wavelets. The proposed algorithm is even better in terms of relative error and mean square error. For actual signal processing, the data compression denoising algorithm is better than the other algorithms and does not lose the original signal energy. The PD ultrasonic signals are spectrally analyzed by using HHT, and signal energy distribution in time and frequency can be clearly described. The main PD ultrasonic signal characteristics can be extracted currently from the marginal and Hilbert spectra. The results of this study will be helpful for the diagnosis of PD faults in large motors. [ABSTRACT FROM AUTHOR]

Carbon Fiber Reinforced Polymer (CFRP) composites have a large potential for strengthening and retrofitting steel parts but due to their premature debonding from steel, further data and research are still required for wider application in such situations. In the present paper, the bond characteristics of CFRP-to-steel joints in pull-pull loaded conditions were studied. Monotonic loading of the double strap joints with different bond lengths was applied and the failure modes and interfacial bond-slip curves were obtained. A tri-linear bond-slip model is proposed and it was derived from the experimental data. A closed-form solution approach is also proposed based on the tri-linear bond-slip model. The strength of the CFRP-to-steel interface, the distribution of the relative displacements between bonded materials, the strains developed in the CFRP laminate and the bond stresses along the interface are reported and the closed-form solution is compared with the experimental results. Two cases are selected for presentation: (i) one with the bond length greater than the effective bond length; and, inversely, (ii) one with bond length which is shorter than the effective bond length. The results predicted by the closed-form solutions are shown to be accurate enough when compared to the experiments. [ABSTRACT FROM AUTHOR]

• We used Cr 2 Si 2 Te 6 combined with a tapered fiber as SA to couple into an erbium-doped fiber laser. • A triple-wavelength fiber laser is generated with a novel Sagnac loop structure. In this work, a Cr 2 Si 2 Te 6 -based tapered fiber saturable absorber with a modulation depth of 4.7 % and a saturable intensity of 28.67 MW/cm2 was fabricated by liquid-phase exfoliation. A triple-wavelength erbium-doped mode-locked fiber laser with a Sagnac loop structure was successfully generated. Its output wavelengths were 1560.2, 1561.3, and 1562.8 nm. The basic repetition rate was 0.97 MHz, corresponding to a signal-to-noise ratio of 49 dB. This is the first demonstration of a triple-wavelength mode-locked fiber laser focusing on a two-dimensional ferromagnetic insulator Cr 2 Si 2 Te 6. This experiment shows that this triple-wavelength mode-locked fiber laser has excellent performance. [ABSTRACT FROM AUTHOR]

In this study, the hydraulic fracture propagation mechanism in low-permeability layered rocks was investigated using the true triaxial hydraulic fracturing test system and the Continuum-based Discrete Element Method. Firstly, the mechanical properties of natural cores in reservoirs and interlayers were determined using uniaxial and triaxial testing machines. Secondly, the Kaiser stress effect method was employed to calculate the in-situ stress. To characterize the thickness distribution characteristics of reservoirs/interlayers in layered rocks, the concept of reservoir thickness ratio k δ was proposed. The influence law of k δ on the fracture pressure P f of layered rocks was explored. The fracture elongation r was proposed to describe the extension state of fractures in reservoirs and interlayers, and the effect of k δ on fracture elongation r were analyzed. The spatial morphology and geometrical characteristics of fractures were characterized based on the 3D fractal dimension and fracture opening. The 3D damage variable D V was defined to reveal the damage evolution law of layered rocks during fracture propagation. The research results reveal the fracture propagation mechanism in hydraulic fracturing of layered rocks and provide theoretical guidance for the effective implementation of hydraulic fracturing technology. This study is important for the efficient reconstruction of low-permeability reservoirs with layered media and improving oil and gas recovery. • Reservoir thickness ratio k δ charactering reservoir/interlayer thickness proposed. • 3D reconstruction models of fractures spatial morphology established. • Influence of k δ on the fracture propagation behaviors of layered rock explored. • Spatial morphology and geometrical characteristics of fractures quantified. • 3D damage variable and damage evolution law during fracture propagation obtained. [ABSTRACT FROM AUTHOR]

Fiber reinforced polymer (FRP) composites with anhydride cured epoxy resin matrices are widely used in civil engineering (e.g., pultruded FRP plates and bars), and their thermal aging behavior is a concern when they are subjected to elevated temperatures (e.g., FRP chimney). In the present article, thermal aging of an epoxy resin matrix at 130 °C–160 °C for 30 days was performed, and the effects on the flexural properties, molecular structures, free volume fraction, and mechanical properties were investigated. FTIR spectroscopy indicated that oxidation and molecular rearrangement occurred in the skin of the epoxy samples during thermal aging. Dynamic mechanical thermal analysis (DMTA) further illustrates the dominant effect of the molecular rearrangement in the sample skin with a thickness less than 100 μm, leading to a new high temperature tan δ peak. The free volume fraction of the skin and the bulk epoxy sample was characterized by positron annihilation lifetime spectroscopy (PALS). The results indicate that a noticeable reduction of the apparent free volume fraction occurred in the sample skin, while the bulk sample was only slightly affected. The flexural results indicate that thermal aging obviously reduced the break strain, while the flexural strength was only slightly affected and the modulus increased. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) semiconductors are being considered as alternative channel materials as silicon-based field-effect transistors (FETs) have reached their scaling limits. Recently, air-stable 2D selenium nanosheet FETs with a gate length of 5 µm were experimentally produced. In this study, we used an ab initio quantum transport approach to simulate sub-5 nm gate-length double-gate monolayer (ML) selenene FETs. When considering negative-capacitance technology and underlap, we found that 3 nm gate-length p-type ML selenene FETs can meet the 2013 ITRS standards for high-performance applications along the armchair and zigzag directions in the 2028 horizon. Therefore, ML selenene has the potential to be a channel material that can scale Moore's law down to a gate length of 3 nm. [ABSTRACT FROM AUTHOR]

This paper presents a numerical and experimental investigation on the effects of pore structures on the static mechanical properties of porous sandstone. Three-dimensional (3D) numerical models of porous sandstone with different statistical pore parameters are constructed using a software program and the experimentally acquired data of the parameters. The mechanical properties of sandstone are numerically tested using Brazilian disc split tests to probe the influences of pore structures. A number of physical models having similar statistical characteristics of pores and physical properties with those of the numerical models are produced using modeling materials. Brazilian disc tests and computer tomography tests are performed on the physical specimens with different porosities to clarify the responses of pore structures during failure processes. The numerical analysis implies that pores significantly affect the mechanical properties of porous sandstone such as stress concentration, distribution, and the connection of the failed material elements. It is shown that the statistical distribution of pore radii presents a certain degree of influence on the split failure behavior of porous rock, which is closely related to rock porosity. However, distribution of spatial location of pores has negligible influence on stress distribution, failure mechanisms, and the split tensile strength of the porous media. A porosity of 15% seems to be a threshold porosity, above which the effects of geometrical and statistical characteristics of pore structures on the split mechanical properties of porous rock become significant. The laboratory test verifies that the developed physical models have consistent geometric and statistical characteristics of pores with those of the real sandstone. The measured split mechanical properties of the physical models present good agreement with the predictions of numerical simulations. [ABSTRACT FROM AUTHOR]

In this paper, the influence of salt fog and ambient condition exposure on CFRP-to-steel bonded joints (CSJs) with a near end mechanical anchorage was studied. The tests of the CSJs were carried out with a monotonic loading history respectively with and without a near end mechanical anchorage both unaged and after being exposed to the ageing conditions. The results revealed failures in the adhesive for some CSJs with a near end mechanical anchorage, among which also exhibited the best bond performance both in aged and unaged specimens. Due to the high state of degradation after ageing exposure, local damage of the CFRP located at the gap position of the CSJs was induced by a torsion action during the fixation of the specimen in the tensile machine even prior to the testing, which caused, although locally, severe delamination of the CFRP of the aged CSJs. From the torsion test results, a decrease in the torsional capacity of the CFRP after aging revealed the degradation of the carbon fiber-to-matrix interface. Additional results reflected that a drop in the initial stiffness of the load vs. slip relationship can be observed, caused by a pre-crack with a length of 30 mm in the CSJs. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the prevalence and visual acuity (VA) outcomes of cataract surgery in adults of the Bai Nationality populations in rural China. Methods: We conducted a population-based cross-sectional survey (from randomly selected block groups) of Chinese Bai Nationality aged ≥50 years in southwestern China. Presenting visual acuity (PVA), best corrected visual acuity (BCVA) were recorded and a detailed eye examination was carried out. For all aphakic and pseudophakic subjects identified, information on the date, setting, type, and complications of cataract surgery were recorded. In eyes with VA <20/63, the principal cause of visual impairment was identified. Results: Of 2133 (77.8% of 2742) subjects, 99 people (129 eyes) had undergone cataract surgery. The prevalence of cataract surgery was 4.6%. Surgical coverage among those with PVA <20/200 in both eyes because of cataract was 52.8%. Unoperated cataract was associated with older age. The main barrier to cataract surgery was lack of awareness and knowledge, cost, and fear. Among the 129 cataract-operated eyes, 22.5% had PVA of ≥20/32, 25.6% had PVA of 20/40 to 20/63, 23.3% had PVA <20/63 to 20/200, and 28.7% had PVA<20/200. With BCVA, the percentages were 42.6%, 23.3%, 10.9%, and 23.3%, respectively. Aphakia (odds ratio [OR], 8.49; P<0.001) and no education (OR, 10.18; P = 0.001) or less education (OR, 6.49; P = 0.014) were significantly associated with postoperative visual impairment defined by PVA, while aphakia (OR, 8.49; P<0.001) and female gender (OR, 4.19; P = 0.004) were significantly associated with postoperative visual impairment by BCVA. The main causes of postoperative visual impairment were refractive error, retinal disorders and glaucoma. Conclusions: Half of those with bilateral visual impairment or blindness because of cataract remain in need of cataract surgery in Bai population. Surgical uptake and visual outcomes should be further improved in the future. [ABSTRACT FROM AUTHOR]

Mechanical anchorage devices have the potential to efficiently improve the bond behavior of Carbon Fiber-Reinforced Polymers (CFRP) Externally Bonded (EB) onto steel with an adhesive. Existing relevant studies, however, have been very limited. Against this background, experimental and numerical studies on the double overlapped CFRP-to-steel bonded joints with an end mechanical anchorage were carried out in the present study. Two types of CFRP laminates (i.e. , SIKA CFRP and the other type made in Harbin Institute of Technology – HIT) were used in the bond tests, with or without end mechanical anchorage devices. The test results showed that the end mechanical anchorage had marginal effect on the bond-slip relationship between EB CFRP and steel as well as debonding load, but could increase the ultimate load. It was also found that CFRP laminate from HIT had a better bond performance than that from SIKA, in terms of both debonding load and ultimate load. Using ABAQUS, Finite Element (FE) model was established on such bonded joints and the accuracy was verified with test results. The verified FE model was adopted in a parametric study to further clarify the effect of key parameters on the bond behavior of such bonded joints. [ABSTRACT FROM AUTHOR]

In order to improve the performance in the practical engineering applications including so called low-speed video tracking and large-angle swing scanning imaging at the same time for a three-axis universal inertially stabilized platform (UISP), we propose an adaptive nonsingular fast terminal sliding mode control (ANFTSMC) strategy subjected to the uncertain disturbances and input saturation constraints. First of all, a second-order dynamic model is established with uncertain disturbances and input saturation constraints. Secondly, a nonsingular fast terminal sliding mode controller (NTSMC) is constructed to ensure the system error converges to zero fast in a finite time; meanwhile, a novel reaching law based on a modified normal distribution function is designed to adjust the control gain. Thirdly, an adaptive control law is designed to online estimate the parameters of the lumped uncertain disturbances. Additionally, the stability of the control system is proved by Lyapunov theory. Finally, extensive comparative simulations and experiments are carried out, the results comprehensively show the effectiveness and superiority of the proposed control method, which can accelerate convergence, weaken the chattering, and has the better control accuracy and robust performance both in the low-speed tracking and large-angle swing scanning applications. Moreover, the exact dynamic model and the prior knowledge of the upper bounds of the disturbances are not required during the procedure of the controller design, which make it have more extensive application value in practical engineering. [ABSTRACT FROM AUTHOR]

Effects of salt fog on CFRP-steel bonded joints were studied via simulation by accelerated cycles. CFRP-to-steel double strap joints made of two different types of laminates were subjected to salt fog cycles for 5000 h and Mode-II tests conducted to assess the degradation of their bond capacity at selected time stages of the process. Different mechanisms causing strength losses were found and analyzed. Results showed that the bond capacity of joints increased initially but was reduced at later stages. Corrosion debonding took place in the chamber between 5,000 h and 10,000 h prior to the application of external loading. Combined Attenuated Total Reflectance-Fourier transform infrared (FTIR) spectroscopy and Dynamic Mechanical Analysis (DMA) results showed that severe degradation at the interface of carbon fibers and resin only took place for one type of laminate. Galvanic corrosion was also analyzed and coupling between CFRP and steel developed due to the corrosion product depositions over the components leading to the degradation of the same type of laminate. [ABSTRACT FROM AUTHOR]

As the calculation of transformer no-load characteristics measured by low-frequency test method is not perfect, different interpolation methods are explored to fit and convert the transformer's volt-ampere characteristics under power frequency (50 Hz) excitation to find the best interpolation fitting conversion method. The no-load test of transformer is carried out by using 10 Hz, 15 Hz, 20 Hz low-frequency square wave and triangular wave excitation. Then the measured excitation voltage, excitation current and no-load loss are converted to those of 50 Hz sine wave excitation. The converted volt-ampere characteristic curve is calculated by the proposed algorithm, and compared with the measured results under the 50 Hz sine wave excitation. Experiments show that under the condition that the magnetic flux amplitudes are equal at each frequency of non-sinusoidal and sine waves, whether it is square wave or triangular wave excitation, the volt-ampere characteristic curve converted to the 50 Hz sine wave excitation by the proposed method can better approximate the curve of the measured 50 Hz sine wave excitation. The average values of the relative errors of the converted excitation current of the three frequencies are within 4%, and those of the converted excitation voltage of the square wave are within 1.1%, and those of the converted excitation voltage of the triangular wave are within 0.47%. Compared with the generalized Steinmetz equation method and the multi-frequency method, the proposed method has a better conversion effect and can almost replace the no-load test results of the 50 Hz sine wave, which has practical value in engineering. [ABSTRACT FROM AUTHOR]

Brazilin possesses anticancer effects, but the mechanisms are poorly understood. This study investigated the mechanisms of brazilin‐induced cell death in the T24 human bladder cancer cell line. Low serum cell culture and the lactate dehydrogenase assay were used to confirm the antitumor effect of brazilin. Annexin V and propidium iodide double staining, transmission electron microscopy, fluo‐3‐AM assay for Ca2+ mobilization and caspase activity assay were performed to identify the type of cell death after brazilin treatment. Mitochondria membrane potentials were measured using JC‐1. Quantitative real‐time polymerase chain reaction and western blot analyses were performed to verify the expression of the necroptosis‐related genes and proteins receptor interacting protein 1 (RIP1), RIP3 and mixed lineage kinase domain‐like (MLKL). The results showed that brazilin induced necrosis in T24 cells and upregulated the mRNA and protein levels of RIP1, RIP3 and MLKL and Ca2+ influx. The necroptosis‐mediated cell death was rescued by the necroptosis inhibitor necrostatin‐1 (Nec‐1), but not by the apoptosis inhibitor z‐VAD‐fmk. Brazilin repressed caspase 8 expression and decreased the mitochondrial membrane potentials; both effects were partially reversed by Nec‐1. Brazilin induced physiological and morphological changes in T24 cells and RIP1/RIP3/MLKL‐mediated necroptosis might be involved. In conclusion, the results confirm the involvement of necroptosis in brazilin‐induced cell death and suggest that brazilin could be explored as an anticancer agent against bladder cancer. [ABSTRACT FROM AUTHOR]

Despite the great prosperity and fast development of image segmentation technology, threshold selection method is still the best choice in many practical applications. The state-of-the-art threshold selection methods perform poorly in segmenting many images with different modalities, such as the magnetic resonance images, cell images, and laser line images. Thus, it is desirable to come up with a more robust method that could segment images with different modalities with the optimum accuracy. To this end, the method should be flexible and its parameters should be adjustable for different types of images. In this paper, we propose to compute the threshold based on the slope difference distribution, which is computed from the image histogram with adjustable parameters. First, the pixels are clustered based on the peaks of the slope difference distribution into different pixel classes. Second, the threshold is selected based on the valleys of the slope difference distribution to separate the pixel classes. The robustness of this threshold selection method relies on the adjustable parameters that could be calibrated to achieve the optimum segmentation accuracy for each specific type of images. The proposed threshold selection method is tested on both the synthesized images and the real images. Experimental results show that the proposed method outperforms the state-of-the-art methods as a whole. [ABSTRACT FROM AUTHOR]

Zn2C8H32N4O16S4, triclinic, P1 (no. 2), a = 9.0313(9) Å, b = 9.6075(14) Å, c = 15.3044(15) Å, α = 89.933(2)°, β = 78.579(1)°, γ = 68.878(1)°, V = 1210.6(2) Å3, Z = 2, Rgt (F) = 0.0323, wRref (F2) = 0.1043, T = 100(2) K. [ABSTRACT FROM AUTHOR]

This study proposes a novel inter‐turn fault diagnosis method for a permanent magnet synchronous machine. Search coils are set on every stator tooth to measure the tooth fluxes. The high‐order harmonics produced by the inverter are adopted to diagnose the inter‐turn fault existence and locate the fault tooth. The fault severity coefficient is proposed on the basis of theoretical analysis and can identify the fault severity. A comparative[AQ ID=Q1] analysis of a traditional method based on co‐simulation shows that the proposed method is sensitive and that the fault severity coefficient is accurate, intuitive and independent of the operating condition of the motor. An experimental platform is set up, and it validates the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

In the present article, effects of elevated temperature treatment on the flexural fatigue behavior of a pultruded basalt fiber reinforced epoxy plates (BFRPs) were investigated. Elevated temperature treatment conditions were set as 150 and 250°C for 0.5, 1, and 2 h in an oven. The static testing results revealed that elevated temperature treatment only brings in slight degradation in the flexural properties of the BFRP. However, the short beam shear strength (SBS) was deteriorated significantly. Dynamic mechanical thermal analysis (DMTA) results indicates that elevated temperature treatment at 150°C mainly shows a post‐curing effect on the resin matrix, while elevated temperature treatment at 250°C leads to fiber debonding and decomposition of the resin. The S‐N curves of BFRP (untreated and treated 150 and 250°C for 1 h) show that the elevated temperature treatment decreased the fatigue lives of BFRP remarkably, especially under high strain ratio. As indicated, elevated temperature treatment accelerates the growth of the damages due, mainly, to the deteriorated fiber–resin bonding property and increased void content. POLYM. COMPOS., 39:1731–1741, 2018. © 2016 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

A 3D electromagnetic model of the end region of a 1550 MW nuclear generator is set up. The electromagnetic forces on the involute and nose parts of the end winding under a rated operation are obtained through the 3D time-step finite element method. The electromagnetic forces on different coils in the same phase are analyzed. By changing the rotor’s relative length and stator coil’s linear length in the 3D electromagnetic model, the electromagnetic force distributions on the end winding are obtained. The influence of each structure change on the electromagnetic force in different directions is studied in detail. Conclusions that can be helpful in decreasing the electromagnetic forces on the end winding through optimizing the end region design are presented. [ABSTRACT FROM AUTHOR]

Utilizing ductile adhesive on CFRP-reinforced steel structures makes the bonded interface with good resistance to dynamic and fatigue loading, which is suitable for the rehabilitation of steel bridges. Currently, considerable studies on the aspect of the CFRP–steel interface are focused only on mode-II loading, ignoring the effects of mode-I loading which could lead to a catastrophic collapse of the retrofitted structures. In the present paper, modified CFRP-to-steel bonded double overlapped joints with various initial peeling angles (θ) were manufactured in order to consider mode-I loading and study the bond behavior of CFRP-to-steel joints under mixed mode-I&II loading. The results showed that the bonded side with weaker adhesion between CFRP and adhesive debonded first and presented a CFRP-adhesive interfacial debonding mode, while the debonding of the other side was delayed and showed a cohesive failure mode in the adhesive. The bond shear stress vs. slip relationship of the debonded side showed to have a bi-linear trend in which the bond strength and interfacial fracture energy were low whilst the other side showed a trapezoidal relationship with a constant plastic plateau and with higher interfacial fracture energy. It was found that sudden debonding caused a quick propagation in the CFRP strain as well as on the global interfacial slip of the joints. It was also found that the peeling angle had significantly deteriorated the local bond response in mode-II, i.e. the trapezoidal bond shear stress vs. slip relationship in the joints with θ = 0 ° shifted to a bi-linear relationship in the joints with θ = 1 ° , θ = 2 ° and with θ = 3 ° in which the bond strength, slip and fracture energy, all decreased very much. Moreover, with θ = 4 ° was experimentally determined as the threshold angle from which the associated mode-I loading can, per se , separate the CFRP from steel. • A review of the bond behavior of CFRP-to-steel joints subjected to mode-I, mode-II and mixed mode-I&II loading is presented. • Modified CFRP-to-steel bonded joints were conceived, allowing assessment of the bond behavior considering mode-I loading. • Different bond qualities in both sides of the CFRP-to-steel double overlapped joints were identified. • Influences of the initial peeling angles on the bond performance of the CFRP-to-steel joints were analyzed thoroughly. • Degradation of bond shear stress vs. slip response due to mode-I loading was experimentally observed. [ABSTRACT FROM AUTHOR]

A quantification method for evaluation of the fracability of shale is essential for optimizing hydraulic fracturing of shale gas reservoirs and enhancing shale gas recovery. To quantitatively evaluate the fracability, seven sets of shale cores are drilled from the reservoirs at different depths of an oilfield in the east of China. The influences of six fracability-related mechanical and physical characteristics of shale, i.e. brittleness, brittle mineral content, clay mineral content, cohesion, angle of internal friction, and unconfined compressive strength, are analyzed. A mathematical model taking account of significance of the influencing factors is proposed based on analytic hierarchy process (AHP) to evaluate the fracability according to their different effects on shale fracability. The analysis indicates that the fracability decreases with the increase of reservoir depths. The hydraulic fracturing tests of the shale cores are conducted to verify the accuracy of the quantification method. The fractal geometry is used to characterize the fracture degree of the shale. It is shown that a larger fractal dimension of the fracture network corresponds to a better fracability of shale. The more complex the fractures are, the larger the fracability of shale is. The experimental data coincide with the results of the proposed evaluation model. [ABSTRACT FROM AUTHOR]

C15H13N5O9Zn2, monoclinic, P21/n (no. 14), a = 6.7739(13) Å, b = 14.160(3) Å, c = 18.506(4) Å, β = 97.908(4)°, V = 1758.1(6) Å3, Z = 4, Rgt(F) = 0.0597, wRref(F2) = 0.1125, T = 298(2) K. [ABSTRACT FROM AUTHOR]

The addition of nano-additives provides a path to improve joint performance. However, it is not clear if the use of these materials can alter the susceptibility of bonded joints to the presence of defects. This work aims to shed some light on this matter, by testing the performance of defective joints bonded with adhesives modified with nano-additives. Two different kinds of carbon-based nano-platelets, including graphene (G) and graphene oxide (GO), were used in this work as additives for adhesives used to bond single lap joints (SLJs). Bulk specimens, as well as three geometrically different SLJs were manufactured and tested. One configuration was manufactured without defects (WO), another with a disbond defect in the middle of the overlap, and another with a disbond defect on the edge of the overlap, known as a side defect (SD). These specimens were bonded with a neat epoxy adhesive and with the same adhesive modified with the addition of 0.3 wt% of G and GO. The addition of G and GO was found to improve Young's modulus and the strength of the epoxy adhesive, while also decreasing its toughness. Dual effect of G and GO addition on improving the strength of the neat epoxy and WO SLJs while reducing the strength of some defective SLJs is also discussed using FT-IR and Raman spectrometry as well as scanning electron microscope pictures of the fracture surfaces. [ABSTRACT FROM AUTHOR]

Despite the rapid technical advancement of augmented reality (AR) and mixed reality (MR) in minimally invasive surgery (MIS) in recent years, monocular-based 2D/3D reconstruction still remains technically challenging in AR/MR guided surgery navigation nowadays. In principle, soft tissue surface is smooth and watery with sparse texture, specular reflection, and frequent deformation. As a result, we frequently obtain only sparse feature points that give rise to incorrect matching results with conventional image processing methods. To ameliorate, in this paper we enunciate an accurate and robust description and matching method for dense feature points in endoscopic videos. Our new method first extracts contours of the low-rank image sequences based on the adaptive robust principal component analysis (RPCA) decomposition. Then we propose a multi-scale dense geometric feature description approach, which simultaneously extracts dense feature descriptors of the contours in the original Euclidean coordinate space, the accompanying 3D color coordinate space, and the derived curvature-gradient coordinate space. Finally, we devise a new algorithm for both global and local point-wise matching based on feature fusion. For global matching, we employ the fast Fourier transform (FFT) to reduce the dimension of the dense feature descriptors. For local feature point matching, in order to enhance the robustness and accuracy of the matching, we cluster multiple contour points to form "super-point" based on dense feature descriptors and their spatio-temporal continuity. The comprehensive experimental results confirm that our novel approach can overcome the highlight influence, and robustly describe contours from image sequences of soft tissue surfaces. Compared with the state-of-the-art feature point description and matching methods, our analysis framework shows the key advantages of both robustness and accuracy in dense point-wise matching, even when the severe soft tissue deformation occurs. Our new approach is expected to have high potential in 2D/3D reconstruction in endoscopy. [Display omitted] • Accurate and robust contour description for soft tissue. • Multi-scale, dense, and hybrid geometric feature descriptors in endoscopic images. • Global and local point-wise feature point matching. • Our method overcomes the problems of highlight and sparse texture in feature extraction, and demonstrates its potential applications in 2D/3D reconstruction for endoscopy. [ABSTRACT FROM AUTHOR]

In this paper the dynamical characteristics of a ferrofluid acceleration sensor are studied experimentally and theoretically. The stiffness coefficient and damping coefficient are key factors in dynamical characteristics of a ferrofluid acceleration sensor. The damping coefficient depends on the viscosity of ferrofluid. The experimental data is very close to theoretical calculation. [ABSTRACT FROM AUTHOR]

Demagnetization and eccentricity are unique and common rotor faults of permanent magnet synchronous motors, respectively. These important factors affect reliability and security of motor drive systems. Online monitoring and real-time diagnosis are typically required in highly reliable application scenarios. The influence of demagnetization and eccentricity faults on spatiotemporal distribution of stator tooth flux based on a stator magnetic flux detection device with multiple search coils is analyzed in this article by establishing a mathematical model of stator tooth flux with corresponding faults. Moreover, a method for extracting rotor fault features and formulating the corresponding fault diagnosis is proposed. Simulations and experiments showed that the proposed diagnosis method can effectively identify the corresponding fault type and diagnose the number of demagnetization poles, degree of demagnetization, and magnitude and orientation of eccentricity ratio. The proposed method can provide an important basis for the operation and maintenance of the motor, help reduce losses due to faults, and improve reliability of the motor and the entire system. [ABSTRACT FROM AUTHOR]

• A passively mode-locked EDF laser using an Sb 2 S 3 -PVA SA. • Evolution of multiple pulses from onefold to sixfold pulses. • Pump hysteresis phenomenon. • Relationship of RF modulation period and pulse interval of multi-pulse bunch. The evolution of multiple pulses and the pump hysteresis phenomenon were observed in a passively mode-locked Er-doped fiber laser using an Sb 2 S 3 -PVA saturable absorber. As the pump power was increased, the generations of onefold, twofold and threefold pulses were meticulously documented. When the pump power was decreased, the evolution of fivefold and sixfold pulses was carefully recorded, accompanied by a clear pump hysteresis phenomenon. A thorough analysis was conducted to examine and reveal the inversely proportional relationship between the RF spectrum modulation periods and the total pulse intervals of the multi-pulse bunches including from onefold to sixfold pulses. [ABSTRACT FROM AUTHOR]

Background: Urinary bladder carcinoma is characterized by high post-operative recurrence rates. Sufu'ning lotion, prepared with Lignum Sappan, can reduce the recurrence of urinary bladder carcinoma. Objectives: The present study describes a methodology for extracting and obtaining high purity brazilin from Lignum sappan and evaluates its effects on urinary bladder carcinoma, in vitro and in vivo. Materials and Methods: The brazilin was extracted from Lignum sappan, purified and identified. The purified brazilin was assessed in vitro for its effects on tumor cell viability and growth using human (T24) and mouse urinary bladder (BTT) cancer cell lines. The role of brazilin in the inhibition of the cell cycle was determined by flow cytometry. The in vivo activity of brazilin was assessed based on the survival of tumor-bearing mice. Results: Brazilin was purified of 99.10% purity and was bioactive as it significantly (P < 0.05) inhibited the growth of T24 and BTT cells. The IC50was 10.08 μg/ml for T24 cells and 8.76 μg/ml for BTT cells after 48 h of treatment. Brazilin blocked the cell cycle progression in the G2 phase. Brazilin (100, 200 and 300 mg/kg) significantly (P < 0.05) increased the survival of BTT tumor-bearing T739 mice and T24 tumor-bearing BALB/c nude mice. Conclusion: The methodology described for the extraction of brazilin from Lignum sappan yields high purity and bioactive brazilin. The extracted brazilin exerts marked inhibitory effects on urinary bladder cancer cells in vitro and in vivo. [ABSTRACT FROM AUTHOR]

Tight multilayered hydrocarbon reservoirs are typical in unconventional oil and gas extraction, in which widespread bedded interfaces have crucial effects on hydraulic fracturing propagation behavior. However, because of the complex natural properties of bedded interfaces in natural layers, such as geometric structure, distribution, strength, and contact conditions, their effects on fracture propagation and governing mechanisms are not well understood. In particular, traditional theoretical models are not suitable for characterizing the propagation behavior of hydraulic fractures in multilayered reservoirs and conventional numerical methods cannot effectively simulate the interactions between hydraulic fractures and bedded interfaces. In this study, the adaptive finite element-discrete element method was introduced to probe the effects of bedded interfaces on hydraulic fracture propagation. Different numerical models of five deviation angles of representative bedded interfaces were established based on the geometric and physical parameters of natural multilayered reservoir rocks. Some novel techniques (local remeshing near the fracture tips to guarantee accurate fracture propagation path, mesh coarsening to improve the computation efficiency, characterization technology for bedded interfaces and contacts between layers, and hydro-mechanical coupling between fluid flow in fracture network and porous rock matrix in the fracturing process) were comprehensively utilized. Furthermore, the fracturing-induced microseismic damaged and contact slip events were identified based on the computed moment tensors to detect the interactions between the hydraulic fractures and bedded interfaces. The results of the cases with single and multiple perforations in horizontal wells show that the bedded interfaces disturb the stress continuity, reselect propagation direction of hydraulic fractures in multiple perforations, induce hydraulic fracture growth, and promote the occurrences of fracturing-induced damaged and contact slip events. The offset and deflection of hydraulic fractures increase with increasing deviation angles between hydraulic fractures and bedded interfaces and the offset vanishes when the deviation angle is 0°. • Adaptive finite element-discrete element method was proposed. • The effects of bedded interfaces on hydraulic fracture propagation were studied. • Models of bedded interfaces of multilayered reservoir rocks were developed. • Bedded interfaces disturb the stress continuity and provoke fracture growth. • Bedded interfaces promote fracturing-induced microseismic events. [ABSTRACT FROM AUTHOR]

Summary: The heterogeneity of tight reservoirs significantly influences hydrofracturing behaviours, such as crack morphology, type, initiation, propagation, and distribution. The accurate characterisation of the influencing mechanisms has become a pivotal issue in enhancing the fracturing stimulation of tight reservoirs, as well as in the prediction of tight oil and gas production. In this study, the hydrofracturing behaviours of heterogeneous glutenites and their influencing mechanisms were numerically investigated based on bonded particle models (BPMs). The geometry and mechanical properties of the natural glutenites were obtained using microfocus computed tomography (CT) and triaxial tests and were used to construct heterogeneous BPMs. The hydrofracturing behaviours of the heterogeneous BPMs under various in‐situ stresses were analysed with hydro‐mechanical coupling effects considered and compared with those of homogeneous BPMs under the same conditions. The numerical results show that gravels in heterogeneous glutenites inhibit crack propagation. The shear cracks that appear in the initial stage of crack development subsequently propagate and distribute around the injection hole, and there are fewer hydraulic shear cracks than tensile cracks. The crack morphologies of BPMs are found to be consistent with the experimental forms. The numerical simulation provides a way to understand the mechanisms that govern the hydrofracturing crack types and propagation of heterogeneous reservoirs. [ABSTRACT FROM AUTHOR]

• This paper proposes a method called 2DWT-CNN for identifying DC bias magnetism conditions in transformers by studying the magnetostrictive effect of ferromagnetic materials and analyzing the dynamic process of core deformation. • A DC bias vibration test platform was built and vibration signals were collected from the core and shell of the transformer. • A two-dimensional transformation method of vibration signal is proposed to extract magnetic bias features by analyzing the magnetostrictive characteristics of transformer core under DC bias magnetic. • This paper successfully applies the microscopic process of magnetostriction to the macroscopic and practical testing of transformer bias conditions. Abnormal vibration of transformers under DC bias magnetism may cause permanent damage to its mechanical structure. Considering the magnetostrictive effect of the core is the main source of vibration in transformers, this paper proposes a method called 2DWT-CNN for identifying DC bias magnetism conditions in transformers by studying the magnetostrictive effect of ferromagnetic materials and analyzing the dynamic process of core deformation. Specifically, the electromagnetic vibration signals of the core and the shell of the transformer were acquired separately on the experimental platform. Then, based on the expansion and contraction characteristics of the core under DC bias magnetism conditions, the magnetic vibration features were extracted using the 2D wavelet transform. Finally, a bias magnetism recognition method called two-dimensional wavelet-convolutional neural network (2DWT-CNN) was established by combining convolutional neural networks as the classifier. The experimental results show that the recognition model has a classification accuracy of almost 100% for the core test points and a prediction accuracy of around 97% for the points located in the transformer's shell. Therefore, the 2DWT-CNN, which takes magnetostrictive effects into account, is an effective method for identifying bias magnetic conditions and can successfully apply the microscopic process of magnetostriction to the macroscopic and practical detection of transformer bias magnetic conditions. [ABSTRACT FROM AUTHOR]

• A human thoracic tissue lung tumor model for calculating magnetothermal effects is established. • The magnetothermal generation model is designed and applied. • The accuracy of the numerical model is verified by the experimental and computational comparison of the magnetothermal gel for tumor treatment. • The temperature distribution of the magnetothermal gel is investigated by infrared measurements and model calculations. • The effects of different influencing factors on the temperature of the magnetothermal gel are discussed to evaluate the effect of tumor treatment. This paper proposes a medium frequency magnetothermal treatment method, which can be used for a certain depth of thermal hyperthermia of tumor tissue in vivo. Firstly, a magnetothermal treatment program using a vortex coil is designed with a medium frequency alternating magnetic field, which can better realize the external implementation. Next, the electromagnetic field of the vortex coil is simulated by finite element method, and the electromagnetic field distribution characteristics of the system are obtained for treatment reference. Then, the preparation and composition design of the gel suitable for the magnetothermal effect are studied, and the temperature rise experiment is carried out to verify the reliability of the temperature rise of the magnetothermal gel. Finally, the human thoracic cavity tissue model is established to calculate the magnetothermal effect of the gel on the lung tumor tissue. And the thermal effect and temperature distribution of different physical parameters on the tissue are obtained. The results show that the magnetothermal therapy can penetrate non-magnetic barriers and effectively generate a temperature rise on the magnetothermal gel injected into the body, so that the tumor tissue in a certain space is inhibited by the temperature rise in a short time. Therefore, the research results in this article provide important theoretical and clinical value for non-invasive hyperthermia of tumors in vivo. [ABSTRACT FROM AUTHOR]

We have theoretically studied the propagation of Airy beams in a close- Λ three-level atomic vapor which is coupled with two optical fields and a microwave field. The analytical expression of susceptibility for the probe beam is deduced under EIT condition. Due to the role of the microwave field, the refractive index of atomic medium for the probe beam is periodically varying along the propagation direction. By utilizing the S-matrix, we find that the acceleration of Airy beams can be feasibly manipulated and modulated in a wavy parabolic way. This self-bending with special wavy shape may afford potential applications in accelerating microparticle along a wavy parabolic path. [ABSTRACT FROM AUTHOR]

When HVDC transmission lines operate in the monopole ground return mode or asymmetric bipolar mode, DC current flows in the earth and DC magnetic bias will arise in neutral point grounding (NPG) transformers. In this work, the model to calculate the potential distribution for multi-layer soil structure is set up, then the magnetic bias current (MBC) is calculated. The magnetic field distribution in the NPG transformer is obtained according to MBC, and electromagnetic energy and force in the transformer are calculated. Finally, the influence on MBC, electromagnetic energy and force caused by soil parameters are investigated. Results indicate that thickness of the first layer and resistivity of the second layer have a greater contribution to MBC, electromagnetic energy and force. To avoid excessive vibration of the NPG transformer, the soil at grounding electrode with a greater thickness in the first layer and lower resistivity in the second layer is preferred. [ABSTRACT FROM AUTHOR]

The Taoer River, a representative ecologically sensitive area in Northeast China, has undergone great climate changes and rapid social developments since 1961. Subsequently, a substantial alteration of the streamflow regime was observed and severe eco-environmental problems were becoming prominent. To provide decision makers the scientific basis for effective resource management and sound future planning, it is crucial to understand and assess the impacts of the climate variability and human activities on streamflow in this region. In this study, we combined an observation-based statistical analysis and physical modeling experiments to address this broad question. The Mann-Kendall and Sen's slope were used to examine the trends and the moving t test was used to identify change points for the streamflow, precipitation, and potential evapotranspiration datasets. A statistically significant upward trend ( α = 5 %) was found for annual streamflow. An abrupt change point was identified in 1985 for the basin outlet station at Taonan. Accordingly, the streamflow was divided into baseline and changed period for attribution analysis. To investigate the impacts of climate change and human activities on annual streamflow, we applied a distributed hydrological model and six Budyko-type functions during the two periods. The results indicated that climate change and human activities accounted for about 45 and 55 % of the changes in streamflow, respectively. [ABSTRACT FROM AUTHOR]

Drought is one of the most costly natural disasters in the world. Understanding the drought characteristics in space and time will help deepen our apprehension of the drought formation and evolution mechanisms. It can also contribute to design monitoring system for drought warning and mitigation. In this study, we analyzed meteorological droughts, using the Standardized Precipitation Index, for Lancang River Basin, Southwest China. The 46-year (1960-2005) daily precipitation observations from 35 meteorological stations in the basin were used to derive the drought index. Spatial patterns and temporal patterns of the drought characteristics at multiple scales were investigated. The results utilizing the Principal Component Analysis and K-means clustering methods suggest that the study area can be divided into four sub-regions geographically with each sub-region having its own distinctive temporal evolution patterns of droughts. The temporal variability of droughts was investigated using the Empirical Mode Decomposition (EMD) analysis and the wavelet method. The EMD analysis showed that more than 60 % of the variance of the drought is associated with intra-decadal fluctuations in precipitation, except for one sub region, represented by the Changdu station. The wavelet transform showed an evolution of the main cycle near 3-7 years for most parts of the study area. [ABSTRACT FROM AUTHOR]

Background: Anterior talofibular ligament (ATFL) injury is a commonly seen sports-related injury and a major underlying pathology of chronic ankle instability. However, it is difficult to accurately identify chronic injury of the ATFL. Purpose: To investigate the value of ultrasound (US) examination in identifying chronic ATFL injury. Material and Methods: We evaluated 83 consecutive patients who underwent US examination for diagnosis of the ATFL injury and subsequent ankle arthroscopy. The arthroscopic findings were used as the reference standard. Results: Forty-four patients were found to have ATFL injury on arthroscopy. The accuracy of US examination for the detection of ATFL injury was 95.2%, with sensitivity of 97.7%, specificity of 92.3%, positive predictive value of 93.5%, negative predictive value of 97.3%, positive likelihood ratio of 12.7, and negative likelihood ratio of 0.025. Conclusion: US examination is a reliable and accurate method to evaluate chronic ATFL injury. [ABSTRACT FROM AUTHOR]

The characterization of pore structure in rocks is relevant in determining their various mechanical behaviors. Digital image processing methods integrated with fractal theory were applied to analyze images of rock slices obtained from industry CT, elucidating the characteristics of rock pore structure and the relationship between porosity and fractal dimensions. The gray values of pixels in CT images of rocks provide comprehensive results with respect to the attenuation coefficients of various materials in corresponding rock elements, and these values also reflect the effect of rock porosity at various scales. A segmentation threshold can be determined by inverse analysis based on the pore ratios that are measured experimentally, and subsequently binary images of rock pores can be obtained to study their topological structures. The fractal dimension of rock pore structure increases with an increase in rock pore ratio, and fractal dimensions might differ even if pore ratios are the same. The more complex the structure of a rock, the larger the fractal dimension becomes. The experimental studies have validated that fractal dimension calculated directly from gray CT images of rocks can give an effective complementary parameter to use alongside pore ratios and they can suitably represent the fractal characteristics of rock pores. [ABSTRACT FROM AUTHOR]