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To enhance the adsorption of organic pollutants by clay materials, two types of organic clay adsorbents were prepared by modifying vermiculite(Vt) and silica lamella(SL) with gemini carboxylic betaine〔1, 2-bis(N-methyl-N-carboxymethyl-tetradecylammonium)ethane, MCTA〕 surfactant as modifier. The effects of modifier addition, contact time, initial pH, dye concentration, and temperature on the adsorption performance were investigated using chrysoidine G(CG) as the adsorbent. The results showed that compared with unmodified Vt and SL(23.70 mg/g and 10.56 mg/g), the adsorption capacities of modified MCTA-Vt and MCTA-SL for CG(131.13 mg/g and 58.14 mg/g) were significantly increased. The adsorption mechanism included hydrophobic interactions of alkyl chains,electrostatic interaction of carboxyl functional groups and electron transfer between molecular orbitals. It was shown that using MCTA as modifier could not only provide hydrophobic long chains for clay to improve its hydrophobicity and increase its adsorption capacity for organic pollutants, but also endow clay with N+ cations and —COO- anion functional groups as new adsorption sites, thereby improving the adsorption capacity of clay.

Surface modification of magnesium alloys was performed using a coating process to optimize their performance. Friction stir processing for preparing magnesium-based high-entropy alloy coatings effectively addressed issues such as oxidation, pores, cracks, and poor coating quality found in existing processes. In addition, it substantially enhanced the hardness and wear resistance of magnesium alloys. The micro-structure and elemental distribution for the cross-section and surface for the magnesium-based high-entropy alloy coating had been studied. The impact of magnesium-based high-entropy alloy upon hardness and wear resistance of the magnesium alloy had been analyzed, focusing on its favorable forming and binding characteristics. Finally, the heat conduction process during friction stir processing were discussed in detail. The theoretical basis for the preparation of magnesium-based high entropy coatings was improved.

Cu/Ti dissimilar metal welding components have significant potential applications in aerospace, nuclear industries, and other fields. To achieve a robust connection between titanium (TA2) and copper (T2), this study conducted laser-welding experiments using nickel as an intermediate layer. The influence of a nickel intermediate layer on the joint formation, microstructure, mechanical properties, melting, and element diffusion behavior were investigated. The results revealed that without the addition of a nickel intermediate layer, when the laser beam was biased toward the titanium side during welding, a 17 μm thick layer of intermetallic compounds formed in the copper-side weld region. In this area, a notable concentration of fragile Ti–Cu intermetallic compounds forms, rendering it the weakest point in the joint. As a consequence, the ultimate tensile strength of the joint measures at 131 MPa, which is roughly 55 % of the tensile strength of the copper base material. The introduction of a nickel intermediate layer led to a change in the microstructure of the fusion zone, with Cu–Ti intermetallic compounds dispersed within, preventing the formation of brittle Ti–Cu phases at the copper interface. The addition of the nickel interlayer increased the tensile strength of the TA2-T2 joint to 224 MPa, which is approximately 94 % that of the copper parent material, and the joint exhibited ductile fracture behavior in the copper parent material's heat-affected zone.

Wire and arc additive manufacturing (WAAM), recognized for its capability to fabricate large-scale, complex parts, stands out due to its significant deposition rates and cost-effectiveness, positioning it as a forward-looking manufacturing method. In this research, we employed two welding currents to produce samples of 316 austenitic stainless steel utilizing the Cold Metal Transfer wire arc additive manufacturing process (CMT-WAAM). This study initially evaluated the maximum allowable arc travel speed (MAWFS) and the formation characteristics of the deposition bead, considering deposition currents that vary between 100 A and175 A in both CMT and CMT pulse(CMT+P) modes. Thereafter, the effect of the CMT+P mode arc on the microstructure evolution was analyzed using the EBSD technique. The findings indicate that the arc travel speed and deposition current significantly affect the deposition bead’s dimensions. Specifically, an increase in travel speed or a reduction in current results in reduced bead width and height. Moreover, the employment of the CMT+P arc mode led to a reduction in the average grain size in the mid-section of the sample fabricated by CMT arc and wire additive manufacturing, from 13.426 μm to 9.429 μm. Therefore, the components of 316 stainless steel produced through the CMT+P-WAAM method are considered fit for industrial applications.

【Objective】 Precision agriculture requires a quick and accurate evaluation of the response of yield to managements at different growing stages, which is challenging at the large scales because of the heterogeneity of plants and soils. Remote sensing technologies can plug this gap, and the purpose of this paper is to investigate the feasibility of using unmanned aerial vehicle (UAV) to evaluate the variation in winter wheat yield in response to change in nitrogen fertilization. 【Method】 Canopy spectral information of winter wheat under different nitrogen fertilizations was measured using a multispectral sensor mounted on a UAV at heading, flowering and filling stages, from which we extracted the vegetation indexes. Stepwise regression and random forest models were used to screen the optimal indexes for estimating the wheat yield. 【Result】 Combination of green (G), blue (B), modified soil-adjusted vegetation index 2 (MSAVI2) and soil-adjusted vegetation index (SAVI) at heading stage works best to predict the yield with low AIC (Akaike Information Criterion) and R2=0.65. Combination of excess green (ExG), near infrared (NIR), normalized difference index (NDI), B and modified soil-adjusted vegetation index 2 (MSAVI2) at flowering stage is the best when using the random forest algorithm to predict the yield with low AIC and R2=0.71. The random forest regression model using all vegetation features at filling stages gave the most accurate prediction of the yield with R2=0.76, compared with R2=0.76 when using G, B, ExG, excess red (ExR), normalized difference vegetation index (NDVI), ratio vegetation index (RVI) and normalized difference vegetation index (TNDVI) only. Prediction using B at heading stage, ExG at flowering stage, NIR at filling stage, NDI at filling stage, and excess green-excess red (EXG-EXR) at filling stage predicted a yield with R2=0.76. 【Conclusion】 Combination of the vegetation indexes measured using multispectral sensors at different growing stages can predict the ultimate winter wheat yield, but the accuracy varies. Best results are achievable using a combination of different indexes measured at different growing stages.

With the improvement of remote sensing image resolution, remote sensing image scene classification has become a major difficulty in the research of remote sensing Urban green space spatial layout and site selection. Complex data and network structure affect the processing effect of the traditional Convolutional neural network model, so it is particularly important to design a more efficient Convolutional neural network. This research will first expand the convolution design of the Convolutional neural network to improve the scope of model recognition, then select two methods of structural pruning and separable knowledge distillation for lightweight processing of the model, and finally introduce relevant models for comparative experiments to verify the lightweight effect of the model. The experimental results show that the global average accuracy of the lightweight model based on structural pruning is 95.5%, and the Kappa coefficient value is 0.947; The global classification accuracy of the lightweight model based on knowledge distillation reaches 95.60%, with a Kappa coefficient value of 0.939. It only uses 38.419MB of storage space to recognize a remote sensing image, 4698352 model parameters, and 1397527639 floating-point operations per second. The results show that the expansion convolution and network pruning methods improve the classification performance of the Convolutional neural network, improve the accuracy of the model, and the knowledge distillation method has a better effect in reducing the complexity and making up for the loss of the classification performance of the network model.

Abstract A three-dimensional numerical model based on the volume-of-fluid (VOF) method is typically preferred for studying high-current gas metal arc welding (GMAW) metal transfer mechanism and then controlling it. It is informed that the rotating spray transfer is extremely complicated, and some researchers have focused on simplified models without considering the energy conservation to make analysis manageable for the unstable metal transfer process. Using our created numerical model, the metal transfer of high-current GMAW with shielding gas of different conductivities has been studied by analyzing acting forces and fluid flows in the metal liquid column, especially for the contributions of the self-induced electromagnetic force, equivalent volume force of the capillary pressure of the surface tension (Named surface tension force in this work), static arc pressure. It is found that the unbalanced electromagnetic force greatly promotes the metal rotating motion in 500 A metal inert gas (MIG) welding with pure argon shielding gas and it pushes the metal liquid column to rotate. Considering the arc constricting effect in active shielding gas by simply changing the arc conductivity, it is found that the metal liquid column no longer rotates, it turns to swing since the unbalanced electromagnetic force is large enough to break the rotating motion. The calculated results of the metal liquid column deflected angle and rotating/swing frequency agree well with the experiment of high-speed camera observations.

A novel controller, employing a variable-structure single-neuron adaptive PSD (proportional integral derivative) approach, was proposed for regulating the deposition width variation in the Directed Energy Deposition-Arc (DED-Arc) layer. During experimental trials, the deposition speed was chosen as the manipulated variable, while the width of the deposition layer served as the measured parameter. To facilitate controller design, a vision sensor was custom-designed to accurately detect the width of the deposition layer. The captured image of the deposition layer’s dimensions enabled the precise determination of the deposited thickness, forming the basis for subsequent controller development. In performance assessments, deliberate interference was intentionally introduced into the deposition current, deposition layer height, and the targeted deposition layer width. The assessment involved the controlled deposition of ten-layer components, focusing on width regulation for each deposition layer. The results demonstrate that the proposed controller significantly enhances the deposition process stability, particularly within a range of desired deposition widths from 7.5 mm to 8.3 mm.

For the welding process of thick-walled structural components in liquid rocket engines, the activated-flux TIG method can effectively address issues such as the formation of intermetallic phases in the weld seams, thereby enhancing mechanical performance. The present study investigates the activated-flux TIG welding technique on 10mm thick 1Cr21Ni5Ti duplex stainless steel plates. Various activated-flux, including -SiO2, TiO2, V2O5, NiO, MnO2, CaO, AlCl3, CaF2, B2O3 Cr2O3, and Al2O3, were examined to understand their impact on the weld-bead geometry. The aim was to determine the optimal activator ratio for the effective welding of 1Cr21Ni5Ti duplex stainless steel. The weld-shift experiment confirmed that the deep penetration observed in flux-assisted welding is attributed to Marangoni convection in the molten pool. Comprehensive evaluations and analyses were performed on the microstructure and mechanical properties of the normal welded joint and the A-TIG welded joint. Finally, the study delves into a discussion on the factors influencing changes in the weld penetration, microstructure, and mechanical properties of the weld.

Dynamical controls on terahertz (THz) wavefronts are crucial for many applications, but available mechanism requests tunable elements with sub-micrometer sizes that are difficult to find in the THz regime. Here, different from the local-tuning mechanism, we propose an alternative approach to construct wavefront-control meta-devices combining specifically designed metasurfaces and globally tuned graphene layers. Coupled-mode-theory (CMT) analyses reveal that graphene serves as a tunable loss to drive the whole meta-device to transit from one functional phase to another passing through an intermediate regime, exhibiting distinct far-field (FF) reflection wavefronts. As a proof of concept, we design/fabricate a graphene meta-device and experimentally demonstrate that it can reflect normally incident THz wave to pre-designed directions with different polarizations under appropriate gating voltages. We finally design a graphene meta-device and numerically demonstrate that it can generate vectorial THz beams with continuously varying polarization distributions upon gating. These findings pave the road to realizing a wide range of THz applications, such as sensing, imaging, and wireless communications.

Amorphous alloys show interesting mechanical properties as well as unique physical and chemical properties due to their atomic stacking structure. However, when partial crystallization occurs in amorphous alloys, it can impact the properties of the original amorphous alloy. To study the crystallization phenomenon in the Zr-based amorphous alloy, a three-dimensional Zr-based amorphous alloy atomic-stacking model was established by molecular dynamics simulations, and the atomic structure evolution of the Zr-Cu amorphous system after partial crystallization was analyzed by the radial distribution function g(r), HA bond index and Voronoi polyhedron. The results showed that adding more copper (Cu) atoms to the Zr-Cu amorphous system greatly improves its stability at high temperatures. The atomic diffusion was analyzed by root-mean-square displacement of atoms (MSD); as the temperature rose, the MSD of atoms also increased, suggesting that the crystallization of the amorphous material occurs due to the short-range diffusion of atoms. The analysis of the mechanism of the high-temperature action time on the Zr80Cu20 amorphous alloy showed that the crystallization phase precipitation rate of the amorphous alloy gradually increases with time, but it does not change linearly.

Abstract Researchers have recently attempted to monitor pool oscillations using the three-dimensional laser vision method. However, the deficiency of simulation software will result in significant capital expenditure. Both simulations and experiments are performed in this study, and the Bessel equation is used to analyze the oscillation mode of a weld pool. The laser dot matrix images of (0, 1), (1, 1), (2, 1), and (0, 2) oscillation modes at different times are obtained via structured laser optical measurement simulation. The oscillation mode of a stationary gas tungsten arc weld pool is analyzed based on laser dot matrix images obtained from a structure laser experiment. Results show that the simulated laser dot matrix images are consistent with the experiment results. The oscillation mode of the weld pool can be recognized based on the laser dot matrix image. This study not only provides conditions for assessing the penetrating state of a weld pool, but also enable a further understanding of the oscillation mode of a weld pool and the development of more effective observation methods and measurement tools to effectively control and improve welding quality.

The interdiffusion and atomic structure of the interface between metallic glass Cu50Zr50 and crystalline Cu were investigated using molecular dynamics simulations. We show that the interdiffusion of atoms at the amorphous/crystalline interface is mainly manifested as the diffusion of crystalline Cu atoms into amorphous atoms, and only a very small amount of amorphous atoms diffuse into crystalline Cu. And the temperature and diffusion time are proportional to the thickness of the diffusion layer. The H-A bond index and Voronoi polyhedron distribution method were used to analyze the structure type and cluster distribution of the interface atoms. the results show that the diffusion will cause the amorphization of the atoms on the crystal side of the interface, and the higher the temperature and the longer the diffusion time, the higher the degree of amorphization of the interface atoms. And the size of the amorphized region is related to the temperature, and the dividing plane between the amorphized atoms and the crystal atoms gradually moves to the crystal side with the increase of temperature. In addition, the diffusion behavior of atoms at the amorphous/crystal interface with different crystal orientations exhibits anisotropy, and some atoms at the interface between the 〈110〉 oriented crystal and amorphous are transformed from FCC structure to HCP structure during the diffusion process.

Abstract Wire arc additive manufacturing (WAAM) has been investigated to deposit large-scale metal parts due to its high deposition efficiency and low material cost. However, in the process of automatically manufacturing the high-quality metal parts by WAAM, several problems about the heat build-up, the deposit-path optimization, and the stability of the process parameters need to be well addressed. To overcome these issues, a new WAAM method based on the double electrode micro plasma arc welding (DE-MPAW) was designed. The circuit principles of different metal-transfer models in the DE-MPAW deposition process were analyzed theoretically. The effects between the parameters, wire feed rate and torch stand-off distance, in the process of WAAM were investigated experimentally. In addition, a real-time DE-MPAW control system was developed to optimize and stabilize the deposition process by self-adaptively changing the wire feed rate and torch stand-off distance. Finally, a series of tests were performed to evaluate the control system’s performance. The results show that the capability against interferences in the process of WAAM has been enhanced by this self-adaptive adjustment system. Further, the deposition paths about the metal part’s layer heights in WAAM are simplified. Finally, the appearance of the WAAM-deposited metal layers is also improved with the use of the control system.

Using wire arc additive manufacturing (WAAM), an alternating current (AC)-assisted WAAM method was proposed to fabricate a Titanium alloy functionally gradient material. The AC was added at the Ti6Al4V filling wire to regulate the microstructure variation from bottom to top during the deposition process. In this study, scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) were used to analyze the microstructure change. Transmission electron microscopy (TEM) was used to study the micro-mechanism. The mechanical performance was tested by Vickers hardness and tensile experiments. Results were obtained for the microstructures of different deposition layers with gradient changes. The results showed that β-lath accumulated around the dislocations, which were hindered by the β phase. Grain size and grain character distributions were remarkably different as the AC increased. The maximum hardness was 480 HV when the value of AC was 20 A, and the highest elongation of the deposited layer was 10.22% with a strength of 650.2 MPa when the AC value was 30 A. The effect of the magnetic field generated by the AC on the flow behavior of the molten pool, the gradual change in microstructure, and the solidification behavior of the molten pool are also discussed.

As a highly effective welding method, PPCA-TIG (Powder Pool Coupled Activating Flux–Tungsten Inert Gas) welding aims to achieve automated activation of TIG welding through the use of suitable activating fluxes. However, due to the unique transitional behavior of activating elements, the mechanism of PPCA-TIG is a little bit different from common activating TIG welding. In this research, a two-dimensional model is established to investigate the effect of four activating fluxes (TiO2, SiO2, MnO2, CaF2) on arc morphology and force. A series of welding experiments is performed to study the impact of the different activating elements on the molten pool. The results show that the increase in the penetration of TiO2 is related to the high arc temperature and great arc force and electromagnetic force in the molten pool. The problem of the softening of 3003 aluminum alloy welded joints is solved. Other activating fluxes are less effective than TiO2. The addition of calcium fluoride significantly affects penetration. The use of TiO2, SiO2 and MnO2 changes the molten pool viscosity and affects the molten pool oscillation, thus affecting the weld quality.

Objective To investigate the effect of metformin on erectile function and its regulation on cavernous fibrosis and autophagy in aged rats, and explore the underlying mechanism. Methods Forty healthy 2-month-old male SD rats were randomly divided into groups A, B, C and D. APO at a dose of 100 mg/kg was injected intraperitoneally to the rats of the former group (at 2 months old) and of the latter 3 group (at 18 months old) to screen the rats with aging-induced erectile dysfunction. Those with ED from the latter 3 groups and those without ED in the group A were employed for the further studies. Group A (control group) was given intragastrical infusion of normal saline for 2 months from the age of 2 months. The rats of the latter 3 groups (18 months old) were injected inragastrically with normal saline, metformin at 300 mg·kg-1·d-1 alone and combined with 0.2 mg/kg compound C for 2 months, respectively. The erectile function was measured by electrical stimulation. The cavernous fibrosis was detected by Masson staining. The autophagy level was detected by Western blotting and transmission electron microscopy. The expression of AMPK/mTOR pathway related proteins was detected by immunofluorescence assay and Western blotting. Results Compared with the group A, the group B had significantly decreased erectile function (P < 0.05), aggravated cavernous fibrosis, and inhibited autophagy and AMPK/mTOR pathway (P < 0.05). Metformin treatment slightly restored the erectile function in the group C (P < 0.05), alleviated the cavernous fibrosis, upregulated autophagy (P < 0.05), and activated the AMPK/mTOR pathway (P < 0.05). But these indicators still did not reach the levels of the group A (P < 0.05). There were no significant differences in above indicators between group D and group B. Conclusion Metformin alleviates cavernous fibrosis and improves erectile function in aging-induced erectile dysfunction rats, which may be related to the activation of AMPK/mTOR pathway to up-regulate autophagy.

This study was conducted to develop a novel tracking control strategy for aeroengines with strong nonlinearity and uncertainty. Compared to existing robust gain-scheduling control strategies, the proposed control strategy has relatively low conservatism and can markedly improve engine performance. An improved on-board adaptive aeroengine model was established to estimate engine performance degradation and eliminate the degradation term contained in the perturbation block of the engine uncertain model in the design process. Robust controllers under engine normal and performance degradation states were designed at a set of operating points and scheduled according to relevant scheduling and health parameters. A desired robust gain-scheduling controller, which works based on performance degradation, can be precisely constructed via this approach. Simulation results are given to demonstrate the effectiveness of the proposed method, where the response speed of engine is improved by 38%.

With ER2319 and B4C powder as feedstocks and additives, respectively, a wire arc additive manufacturing (WAAM) system based on double-pulse melting electrode inert gas shielded welding (DP-MIG) was used to fabricate single-pass multilayer 2319 aluminum alloy. The results showed that, compared with additive manufacturing component without B4C, the addition of which can effectively reduce the grain size (from 43 μm to 25 μm) of the tissue in the deposited layer area and improve its mechanical properties (from 231 MPa to 286 MPa). Meanwhile, the mechanical properties are better in the transverse than in the longitudinal direction. Moreover, the strengthening mechanism of B4C on the mechanical properties of aluminum alloy additive manufacturing mainly includes dispersion strengthening from fine and uniform B4C granular reinforcing phases and fine grain strengthening from the grain refinement of B4C. These findings shed light on the B4C induced grain refinement mechanism and improvement of WAAM 2319 Al alloy.

[Objectives] Since the geometric parameters of the ship air-intake grilles are numerous,the calculation cost of radar wave stealth performance optimizing for all parameters is too high,and the geometric parameter sequences with high Radar Cross Section(RCS) sensitivity need to be mastered.[Methods] In this paper,taking one typical air-intake grille of ship as the object,the parameterized modeling, the electromagnetic scattering calculation parameters and the electromagnetic scattering calculation method of the grille had been carried out. The sensitivity of each geometric parameter to shielding efficiency was calculated by using the central finite difference method.[Results] The variation law of radar scattering characteristics under different geometric parameters,and the geometric parameter sequence for stealth optimization of the air-intake grilles were obtained.[Conclusions] The stealth analysis and sensitivity calculation method constructed in this paper is reasonable and feasible,and can be widely used in the stealth optimization design of naval air-intake grille.

Twin-wire and arc additive manufacturing (T-WAAM) has potential advantages in improving deposition efficiency and manufacturing functionally graded materials (FGMs), thus attracting much attention. However, there are few studies on the droplet transfer mode of T-WAAM. This paper analyzes the droplet transfer mode and arc swing in the “TIG + AC” twin-wire cross-arc additive manufacturing by in-situ observation with high-speed photography, revealing what factors influence the T-WAAM on deposition shaping the quality and what are the key mechanisms for process stability. Experiments show that with the main arc current provided by TIG 100 A and the twin-wire AC arc current 10 A, three different droplet transfer modes, namely the “free transfer + free transfer, bridge transfer + free transfer, bridge transfer + bridge transfer,” can be observed with the twin wires under different feeding speeds. The corresponding deposition and arc swing are quite different in quality. Through comparative analysis, it is found that the frequent extinguishment and ignition of the arc between electrode wires is the main factor for the instability in the additive manufacturing process. The “bridge transfer + free transfer” mode can obtain a large arc swing angle and a stable deposition, in which the cross arc has a significant stirring effect on the molten pool, and the deposition shape is well-made.

In this work, the microstructure and growth behavior of Al-Fe intermetallic compounds (IMCs), which formed at interface of weld steel-aluminum joint, are successfully analyzed via the combination of experiment and physical model. A layer IMCs consists of Fe2Al5 and Fe4Al13, in which the Fe2Al5 is the main compound in the layer. The IMCs layer thickness increases with the increase of the heat input and the maximum thickness of IMCs layer is 22 ± 2 μm. The high vacancy concentration of Fe2Al5 IMCs provides the diffusion path for Al atoms to migrate through the IMCs layer for growing towards to steel substrate. By using the calculated temperature profiles as inputs, the combined 2D cellular automata (CA)-Monte Carlo (MC) model is applied to simulate the grain distribution and interfacial morphology evolution at the Al-steel interface. This 2D model simulates the IMCs nucleation, growth, and solute redistribution. The numerical results are in good agreement with the experimental results, suggesting that the growth process can be divided four stages, and the thickness of the Fe2Al5 layer increases nonlinearly with the increase of the growth time. The whole nucleation and growth process experienced 1.7~2 s, and the fastest growth rate is 8 μm/s. The addition of Si element will influence diffusion path of Al atom to form different interface morphology. The effects of peak temperature, cooling time, and the thermal gradient on the IMCs thickness are discussed. It shows that the peak temperature has the major influence on the IMCs thickness.

Advanced engine control, such as active control, often involves controlling engine with more control variables at a wider frequency range. When the conventional successive-loop-closure technology is applied to design controller with more objectives and controls, it will lead to multi-loop interleaving, and prevent the responses of the lower frequency control loops from meeting the requirements and hence exploiting the potential of the engine. A modified multivariable decoupling method in frequency domain is presented to improve the robustness and decoupling of the system and proved that it is equivalent to Rosenbrock's modified method at a single frequency, and then extended to a weighted formulation on a certain frequency range. Finally, the modified method is used to design steady-state decoupling controller, and a multivariable gain-scheduling controller for large transient is formulated as the weighted function of a family of designed decoupling controllers, whose weights are chosen as transfer function of neural network optimized by BP algorithm. Computational results are presented for controlling the small and large transient of a military aircraft turbofan engine, and the simulations show that compared with standard Hawkins's method, the resultant compensated system designed by the modified method is of better good decoupling and robustness.

For gas metal arc welding (GMAW), increasing the welding current is the most effective way to improve welding efficiency. However, much higher current decreases the welding quality as a result of metal rotating-spray transfer phenomena in the high-current GMAW process. In this work, the external axial magnetic field (EAMF) was applied to the high-current GMAW process to control the metal transfer and decrease the welding spatters. A unified arc-droplet coupled model for high-current GMAW using EAMFs was built to investigate the metal rotating-spray transfer behavior. The temperature fields, flow fields in the arc, and droplet were revealed. Considering all the heat transferred to the molten metal, the Joule heat was found to be the dominant factor affecting the droplet temperature rise, followed by the anode heat. The conductive heat from the arc contributed less than half the value of the other two. Considering the EAMFs of different alternating frequencies, the arc constricting effects and controlled metal transfer behaviors are discussed. The calculated results agree well with the experimental high-speed camera observations.

Using laser beam as main heat source, and trailing arc as an assisted role, aluminum alloy was joined to galvanized steel in a butt configuration. Under suitable welding parameters, a sound welding seam was obtained. The interface intermetallic compounds layer and wetting behavior of weld joint were studied. The assisted arc can improve the wetting and spreading ability of weld pool duo to large temperature field. There are two different types of IMCs: near to the steel side one is Fe2Al5 with tooth-like shape and near to the weld seam side is the other one Fe4Al13 with flocculent-like shape. The highest tensile strength can reach 163 MPa when the fracture occurred at the weld seam.

Pathological cardiac hypertrophy is one of the notable causes of heart failure. Circular RNAs (circRNAs) have been studied in association with cardiac hypertrophy; however, the mechanisms by which circRNAs regulate cardiac hypertrophy remain unclear. In this study, we identified a new circRNA, named circCacna1c, in cardiac hypertrophy. Adult male C57BL/6 mice and H9c2 cells were treated with isoprenaline hydrochloride (ISO) to establish a hypertrophy model. We found that circCacna1c was upregulated in ISO-induced hypertrophic heart tissue and H9c2 cells. Western blot and quantitative real-time polymerase chain reaction showed that silencing circCacna1c inhibited hypertrophic gene expression in ISO-induced H9c2 cells. Mechanistically, circCacna1c competitively bound to miR-29b-2-5p in a dual-luciferase reporter assay, which was downregulated in ISO-induced hypertrophic heart tissue and H9c2 cells. MiR-29b-2-5p inhibited the nuclear factor of activated T cells, cytoplasmic, calcineurin-dependent 1 (NFATc1) to control hypertrophic gene expression. After silencing circCacna1c, the expression of miR-29b-2-5p increased, which reduced hypertrophic gene expression by inhibiting NFATc1 expression. Together, these experiments indicate that circCacna1c promotes ISO-induced pathological hypertrophy through the miR-29b-2-5p/NFATc1 axis.

BACKGROUND: This study was conducted to identify epidemiological characteristics of the first documented CHIK fever outbreak in China and evaluate the effect of the preventive measures taken. METHODOLOGY/PRINCIPAL FINDINGS: From September 1 to October 29, 2010, China's first documented outbreak of CHIK fever occurred in the Xincun community of Wanjiang District of Dongguan city, Guangdong province; 253 case-patients were recorded, of which 129 were laboratory confirmed, with an attack rate of 1%. Before September 18(th) the number of CHIK fever cases remained relatively low in the Xincun community; from September 19(th) onwards, the number of cases increased drastically, with an outbreak peak on October 4(th). Cases were distributed across nine small village groups in the Xincun community, with an attack rate of 0-12% at the village level. The household attack rates ranged between 20% and 100%. No significant difference was found in the attack rate between males and females. There was a significant difference in the attack rate in different age groups (chi-square=18.35, p=0.005); highest in patients aged 60 years or older and the lowest in patients aged under 10. The major clinical characteristics of patients are fever (100%), joint pain (79%) and rash (54%). Phylogenetic analysis of the E1 gene on the five earliest confirmed cases showed that the strains of CHIKV isolated from their sera were highly homologous (up to 99%) with isogeneic strains isolated in Thailand in 2009. After control measures were taken, including killing adult mosquitoes and cleaning breeding habitats of Aedes mosquitoes, the Breteau index and Mosq-ovitrap index decreased rapidly, and the outbreak ended on October 29. CONCLUSION/SIGNIFICANCE: The infection source of the outbreak was imported. Cases showed obvious temporal, spatial, and population aggregation during the outbreak. Comprehensive control measures based on reducing the density of Aedes mosquitoes were effective in controlling the epidemic.