Superior anti-corrosion and self-healing bi-functional polymer composite coatings with polydopamine modified mesoporous silica/graphene oxide

In this article,graphene oxide (GO) and benzotriazole-loaded mesoporous silica nanoparticles (BTA/MSNs)are combined on micro scale through the in situ polymerization of polydopamine (PDA),preparing a self-healing bi-functional GO (fGO) used as nano-fillers for anti-corrosion enhancement of waterborne epoxy(WEP) coatings.Scanning electronic microscopy (SEM) images show that the BTA/MSNs are uniformly distributed on the surface of high aspect ratio GO nanosheets to endow GO nanocontainer characteristics.UV-vis profiles demonstrate that fGO has pH-controlled release function.Modulus at lowest frequency is generally used for comparing the corrosion resistance of organic coatings.Modulus at lowest frequency(1.42 × 107 Ω cm2) after 30 days immersion in 3.5 wt.％ NaCl solution revealed 2 orders of magnitude higher that of blank WEP (1.17 × 105 Ω cm2).With artificial cracks on its coatings,fGO/WEP had no obvious rust compared with blank WEP after 240 h of immersion.We anticipate that self-healing and physical barrier bi-functional nanocontainers improve the traditional anticorrosion coating efficiency with better,longer-lasting performance for shipping,oil drilling or bridge maintenance.     

Template-free preparation of non-metal (B,P,S) doped g-C3N4 tubes with enhanced photocatalytic H2O2 generation

Developing environmentally friendly methods to produce hydrogen peroxide (H2O2) has received increas-ing attention.Photocatalysis has been proved to be a sustainable technology for H2O2 production.Herein,the novel non-metal elements (B,P,and S) doped g-C3N4 tubes (B-CNT,P-CNT,and S-CNT) photocata-lysts were obtained via a hydrothermal synthesis followed by thermal polymerization.By adjusting the precursor,the yield of g-C3N4 tubes (CNT) materials has been greatly improved.The as-prepared B-CNT,P-CNT,and S-CNT photocatalysts show an enhanced photocatalytic H2O2 production with the formation rate constants values of 42.31 μM min-1,24.95μM min-1,and 24.22μM min-1,respectively,which is higher than that of bulk CN (16.40 μM min-1).The doped B,P,S elements significantly enhanced the photocatalytic activity by adjusting their electronic structures and promoting the separation of electron-hole carriers.The results have shown great potential for the practical application of CNT photocatalysts.     

Mechanical(compressive)form of driving force triggers the phase transformation from βto ω&α"phases in metastable β phase-field Ti-5553 alloy

Most of the structural alloys'applications are under static,dynamic,and cyclic forms of loading.Ti-5553 alloy in the beta phase field is being investigated to confirm the mechanism of deformation and phase transformation upon quasi-static and dynamic compression.The Ti-5553 alloy was heat-treated at 900 C(almost 50℃above beta transus temperature)for one hour of soaking time followed by air quenching to achieve a fully β phase field.After that,Dynamic compression(DC)by Split Hopkinson Pressure Bar(SHPB)and Quasi-static compression(QSC)were performed at a strain rate of～103/s and 10-3/s,respectively.Recovered specimens were thoroughly examined by using different tools,such as an Optical microscope(OM),Scanning electron microscope(SEM),High-resolution transmission electron microscope(HRTEM),and Electron backscatter diffraction(EBSD)to get the reliable data for justification of logical conclusions.It is found that the dominating mode of deformation was dislocation slip along with twinning({332}〈113〉)to some extent in both of QSC and DC,but sliding&spalling of the grain boundary is observed more in the former.Stress-induced phase transformation,i.e.,β to α"and 3 toω,took place in the grains saturated with dislocation slips,where the former transformation occurred simultaneously with{332}〈113〉twinning,while β to ω transformation was completed when a set of two adjacent(110)β planes covered±1/6th of the total separation distance between two(next to each other)(111)β planes,by equal but opposite shear in(111)β direction,and it caused 3％shrinkage of two closed packed(110)β planes after transformation.     

Enhanced Q-switching performance of magnetite nanoparticle via compositional engineering with Ti3C2 MXene in the near infrared region

In this work,we reported a new strategy to improve the nonlinear saturable absorption performance of magnetite (Fe3O4) nanoparticles (FONPs) via the compositional engineering with the Ti3C2 MXene in the near-infrared (NIR) region.Based on the DFT simulation,the band structures and work function were significantly modified by the Ti3C2 MXene doping.By using the open-aperture Z-scan technology,the nonlinear optical features of the FONPs@Ti3C2 nanocomposite were significantly improved,show-ing the great potential as the saturable absorber in the pulsed laser.With the nanocomposite as the saturable absorber,the passively Q-switched Nd∶GdVO4 lasers emitted much shorter pulse durations when compared with the pristine FONP saturable absorber.These findings indicated that FONPs@Ti3C2 heterostructure was a promising saturable absorber for the short pulse generation in the NIR region.     

Charge storage coating based triboelectric nanogenerator and its applications in self-powered anticorrosion and antifouling

As a novel energy-harvesting device, a triboelectric nanogenerator (TENG) can harvest almost all mechanical energy and transform it into electrical energy, but its output is low. Although the micro-nano structures of triboelectrode surfaces can improve their output efficiency, they lead to high costs and are not suitable for large-scale applications. To address this problem, we developed a novel TENG coating with charge-storage properties. In this study, we modified an acrylic resin, a friction material, with nano-BaTiO₃ particles and gas phase fluorination. The charge-trapping ability of nanoparticles was used to improve the output of TENG. The short-circuit current and the output voltage of coating-based TENGs featuring charge storage and electrification reached 15 μA and 800 V, respectively, without decay for longtime working. On this basis, self-powered anticorrosion and antifouling systems are designed to reduce the open circuit potential of A3 steel by 510 mV and reduce the adhesion rate of algae on the surface of metal materials. This study presents a high-output, stable, coating-based TENG with potential in practical applications for anticorrosion and antifouling.     

基于DMD的小型近红外光谱仪原理及优化分析

数字微镜器件小型近红外光谱仪器具有检测速度快、灵敏度高、无损伤检测、仪器小型化等优点,广泛应用于化学成分分析和质量检测。然而,作为仪器设计的前提,整个光谱范围的光学优化设计是系统的难点。文中研究了基于数字微镜器件小型近红外光谱仪的光谱成像系统的理论设计方法。该方法采用双配消像差透镜,结合几何像差理论,对小型数字微镜器件近红外光谱仪的设计进行了优化,以降低整个系统的像差。然后,利用光学仿真软件对准直接成像系统进行光学仿真。最终达到设计仿真要求。仿真结果表明,该分光计的整体尺寸小于150 mm×150 mm×150 mm,在工作波段1000~1700 nm范围内,其分辨率优于15 nm。因此,该方法能满足设计要求,在实际应用中具有广阔的应用前景。     

Robust Visual Tracking with Hierarchical Deep Features Weighted Fusion

To solve the problem of low robustness of trackers under significant appearance changes in complex background, a novel moving target tracking method based on hierarchical deep features weighted fusion and correlation filter is proposed. Firstly, multi-layer features are extracted by a deep model pre-trained on massive object recognition datasets. The linearly separable features of Relu3-1, Relu4-1 and Relu5-4 layers from VGG-Net-19 are especially suitable for target tracking. Then, correlation filters over hierarchical convolutional features are learned to generate their correlation response maps. Finally, a novel approach of weight adjustment is presented to fuse response maps. The maximum value of the final response map is just the location of the target. Extensive experiments on the object tracking benchmark datasets demonstrate the high robustness and recognition precision compared with several state-of-the-art trackers under the different conditions.     

Analysis and Optimization of Inside-Cushion Structure in High-Speed Hydraulic Cylinders

An inside-cushion structure with sidestep and taper-shaped plungers is studied to address the problems of high impact and vibration in high-speed hydraulic cylinders. First, the three stages of cushion processes are discussed according to the varying flow area as the piston moves. Then, to establish a precise mathematical model, the states of the flow field are estimated in terms of the Reynolds number. Accordingly, the simulation model parameterized against measured data is developed and verified by experiment. Last, the average velocity, peak cushion pressure, and terminal velocity are defined to evaluate cushion performance. According to these optimized objectives, the non-linear programming by quadratic Lagrange (NLPQL) algorithm is applied to optimize the structure parameters. The optimization results indicate that the peak cushion pressure is reduced by 28% and terminal velocity is reduced by 21% without reduction of average velocity.     

Electronic transport through ruthenium-based redox-active molecules in metal-molecule-metal nanogap junctions

Electronic transport through ruthenium-based redox-active organometallic molecules is measured by self-assembling diruthenium(III) tetra(2-anilinopyridinate)-di(4-thiolphenylethynyl) (trans-Ru2(ap)4(C'CC6H4S-)2 (A) and trans- Ru2(ap)4((C'CC6H4)2S-)2 (B) molecules in nanogap molecular junctions. Voltage sweeps at a high scan rate show low bias current peaks (at +/-0.35 +/- 0.05 V for A and +/-0.27 +/- 0.05 V for B), which change to plateaus in slow bias scans and a second conductance peak at approximately +/-1.05 +/- 0.15 V. The peaks/plateaus are not observed in the return bias sweeps, possibly due to charge storage in the molecules. The energy states for the molecular orbitals of these molecules as estimated from the conductance peaks are in close agreement with the respective energy values from voltammetric measurements in solution.     

莲花美容沙龙，四壁如发

是否曾经想象墙壁可以被“电烫”？日本青年建筑师中村拓志设计的坐落在日本三重县桑名市的莲花美容沙龙正是这样的,白色织物墙充满动感与变化。根据美容室的空闲或占用,而敞开或围合．美容室时而融入公共空间．成为大堂的一部分,时而成为私密空间,让客人独享服务。这种通过材料改变空间形态的手法,让空间与置身空间时的情感都充满连续且微妙的变化。