Enhancing the stability of Ni Fe-layered double hydroxide nanosheet array for alkaline seawater oxidation by Ce doping

Electrocatalytic hydrogen production from seawater holds enormous promise for clean energy generation.Nevertheless,the direct electrolysis of seawater encounters significant challenges due to poor anodic stability caused by detrimental chlorine chemistry.Herein,we present our recent discovery that the incorporation of Ce into Ni Fe layered double hydroxide nanosheet array on Ni foam(Ce-Ni Fe LDH/NF)emerges as a robust electrocatalyst for seawater oxidation.During the seawater oxidation process,CeO_(2)is generated,effectively repelling Cl^(-)and inhibiting the formation of Cl O-,resulting in a notable enhancement in the oxidation activity and stability of alkaline seawater.The prepared Ce-Ni Fe LDH/NF requires only overpotential of 390 m V to achieve the current density of 1 A cm^(-2),while maintaining long-term stability for 500 h,outperforming the performance of Ni Fe LDH/NF(430 m V,150 h)by a significant margin.This study highlights the effectiveness of a Ce-doping strategy in augmenting the activity and stability of materials based on Ni Fe LDH in seawater electrolysis for oxygen evolution.

Values of macular ganglion cell-inner plexiform layer and 10-2 visual field measurements in detecting and evaluating glaucoma

AIM:To assess the performance of macular ganglion cell-inner plexiform layer thickness(mGCIPLT)and 10-2 visual field(VF)parameters in detecting early glaucoma and evaluating the severity of advanced glaucoma.METHODS:Totally 127 eyes from 89 participants(36 eyes of 19 healthy participants,45 eyes of 31 early glaucoma patients and 46 eyes of 39 advanced glaucoma patients)were included.The relationships between the optical coherence tomography(OCT)-derived parameters and VF sensitivity were determined.Patients with early glaucoma were divided into eyes with or without central 10°of the VF damages(CVFDs),and the diagnostic performances of OCT-derived parameters were assessed.RESULTS:In early glaucoma,the mGCIPLT was significantly correlated with 10-2 VF pattern standard deviation(PSD;with average mGCIPLT:β=-0.046,95%CI,-0.067 to-0.024,P<0.001).In advanced glaucoma,the mGCIPLT was related to the 24-2 VF mean deviation(MD;with average mGCIPLT:β=0.397,95%CI,0.199 to 0.595,P<0.001),10-2 VF MD(with average mGCIPLT:β=0.762,95%CI,0.485 to 1.038,P<0.001)and 24-2 VF PSD(with average mGCIPLT:β=0.244,95%CI,0.124 to 0.364,P<0.001).Except for the minimum and superotemporal mGCIPLT,the decrease of mGCIPLT in early glaucomatous eyes with CVFDs was more severe than that of early glaucomatous eyes without CVFDs.The area under the curve(AUC)of the average mGCIPLT(AUC=0.949,95%CI,0.868 to 0.982)was greater than that of the average circumpapillary retinal nerve fiber layer thickness(cpRNFLT;AUC=0.827,95%CI,0.674 to 0.918)and rim area(AUC=0.799,95%CI,0.610 to 0.907)in early glaucomatous eyes with CVFDs versus normal eyes.CONCLUSION:The 10-2 VF and mGCIPLT parameters are complementary to 24-2 VF,cpRNFLT and ONH parameters,especially in detecting early glaucoma with CVFDs and evaluating the severity of advanced glaucoma in group level.

波形钢-UHPC组合桥面板中栓钉-PBL连接件抗剪性能数值模拟研究

针对波形顶板-超高性能混凝土(Ultra-high Performance Concrete,UHPC)新型组合桥面板结构,提出在波形钢板波峰处布置短栓钉,波谷处布置开孔板(Perfobond Leiste,PBL),形成栓钉-PBL组合连接件协同抗剪。为探究该组合连接件的抗剪力学性能,建立组合连接件推出试验及梁式试验的有限元模型,并基于现有试验对模型的正确性进行验证。在此基础上,讨论了栓钉直径、PBL孔径、栓钉抗拉强度和UHPC抗压强度等设计参数对组合连接件抗剪性能的影响规律。通过分析组合连接件在推出试验全过程中的剪力分配规律,揭示了波形顶板-UHPC组合结构中栓钉与PBL剪力连接件的协同工作机理及破坏机理,并基于此提出组合连接件的设计理论和抗剪承载力计算方法。研究结果表明:组合连接件受到的剪力由栓钉和PBL共同承担,增加短栓钉直径、PBL孔径和UHPC强度均可有效提高组合连接件抗剪承载力;栓钉与无贯穿钢筋的PBL连接件抗剪承载力相近时,后者在加载初期承担的荷载较大,并会早于栓钉发生破坏;二者抗剪承载力之比在1.5左右时,大致同时进入破坏阶段,组合效果最佳;提出的栓钉-PBL组合连接件抗剪承载力计算公式的计算结果与有限元及试验结果吻合度较高;抗剪连接程度相同时,采用组合连接件的桥面板受力性能最佳,钢板与UHPC层之间的相对滑移和间隙均最小。

Multi-field coupling and free vibration of a sandwiched functionally-graded piezoelectric semiconductor plate

Sandwiched functionally-graded piezoelectric semiconductor(FGPS)plates possess high strength and excellent piezoelectric and semiconductor properties,and have significant potential applications in micro-electro-mechanical systems.The multi-field coupling and free vibration of a sandwiched FGPS plate are studied,and the governing equation and natural frequency are derived with the consideration of electron movement.The material properties in the functionally-graded layers are assumed to vary smoothly,and the first-order shear deformation theory is introduced to derive the multi-field coupling in the plate.The total strain energy of the plate is obtained,and the governing equations are presented by using Hamilton’s principle.By introducing the boundary conditions,the coupling physical fields are solved.In numerical examples,the natural frequencies of sandwiched FGPS plates under different geometrical and physical parameters are discussed.It is found that the initial electron density can be used to modulate the natural frequencies and vibrational displacement of sandwiched FGPS plates in the case of nano-size.The effects of the material properties of FGPS layers on the natural frequencies are also examined in detail.

Cumulative second-harmonic generation of Lamb waves propagating in a two-layered solid plate

The physical process of cumulative second-harmonic generation of Lamb waves propagating in a two-layered solid plate is presented by using the second-order perturbation and the technique of nonlinear reflection of acoustic waves at an interface. In general, the cumulative second-harmonic generation of a dispersive guided wave propagation does not occur. However, the present paper shows that the second-harmonic of Lamb wave propagation arising from the nonlinear interaction of the partial bulk acoustic waves and the restriction of the three boundaries of the solid plates does have a cumulative growth effect if some conditions are satisfied. Through boundary condition and initial condition of excitation, the analytical expression of cumulative second-harmonic of Lamb waves propagation is determined. Numerical results show the cumulative effect of Lamb waves on second-harmonic field patterns.

MODIFIED LAYER REMOVAL METHOD FOR MEASUREMENT OF RESIDUAL STRESS DISTRIBUTION IN THICK PRE-STRETCHED ALUMINUM PLATE

The integrated structure parts are widely used in aircraft. The distortion caused by residual stresses in thick pre-stretched aluminum plates during machining integrated parts is a common and serious problem. To predict and control the machining distortion, the residual stress distribution in the thick plate must be measured firstly. The modified removal method for measuring residual stress in thick pre-stretched aluminum plates is proposed and the stress-strain relation matrix is deduced by elasticity theory. The residual stress distribution in specimen of 7050T7451 plate is measured by using the method, and measurement results are analyzed and compared with data obtained by other methods. The method is effective to measure the residual stress.

Non-axisymmetrical vibration of elastic circular plate on layered transversely isotropic saturated ground

The non-axisymmetrical vibration of elastic circular plate resting on a layered transversely isotropic saturated ground was studied. First, the 3-d dynamic equations in cylindrical coordinate for transversely isotropic saturated soils were transformed into a group of governing differential equations with 1-order by the technique of Fourier expanding with respect to azimuth, and the state equation is established by Hankel integral transform method, furthermore the transfer matrixes within layered media are derived based on the solutions of the state equation. Secondly, by the transfer matrixes, the general solutions of dynamic response for layered transversely isotropic saturated ground excited by an arbitrary harmonic force were established under the boundary conditions, drainage conditions on the surface of ground as well as the contact conditions. Thirdly, the problem was led to a pair of dual integral equations describing the mixed boundaryvalue problem which can be reduced to the Fredholm integral equations of the second kind solved by numerical procedure easily. At the end of this paper, a numerical result concerning vertical and radical displacements both the surface of saturated ground and plate is evaluated.

General series expression of eddy-current impedance for coil placed above multi-layer plate conductor

This paper presents a closed expression of the layered-plate factor used to calculate the coil eddy-current impedance over the multi-layer plate conductor. By using this expression, the general series of eddy-current impedance can be written directly without solving the undetermined constant equations. The series expression is easy to use for theoretical analysis and programming. Experimental results show that calculated values and measured values are in agreement. As an application, when the bottom layer of the layered plate is a non-ferromagnetic thin layer conductor and the product of the thickness and conductivity of the layer remains unchanged, using the layered-plate factor expression proposed in this paper, it can be theoretically predicted that the eddy-current impedance curves corresponding to different thin layer thickness values will coincide.

Influence of active constrained layer damping on the coupled vibration response of functionally graded magneto-electro-elastic plates with skewed edges

This article makes the first attempt in assessing the influence of active constrained layer damping(ACLD)treatment towards precise control of frequency responses of functionally graded skew-magneto-electroelastic(FGSMEE)plates by employing finite element methods.The materials are functionally graded across the thickness of the plate in terms of modest power-law distributions.The principal equations of motion of FGSMEE are derived via Hamilton’s principle and solved using condensation technique.The effect of ACLD patches are modelled by following the complex modulus approach(CMA).Additionally,distinctive emphasis is laid to evaluate the influence of geometrical skewness on the attenuation capabilities of the plate.The accuracy of the current analysis is corroborated with comparison of previous researches of similar kind.Additionally,a complete parametric study is directed to understand the combined impacts of various factors like coupling fields,patch location,fiber orientation of piezoelectric patch in association with skew angle and power-law index.

Layer-block tectonics of Cenozoic basements and formation of intra-plate basins in Nansha micro-plate, southern South China Sea

Layer-block tectonics （LBT） concept, with the core of pluralistic geodynamic outlook and multilayer-sliding tectonic outlook, is one of new keys to study 3-dimensional solid and its 4-dimensional evolution history of global tectonic system controlled by global geodynamics system. The LBT concept is applied to study the lithospheric tectonics of the southern South China Sea （SCS）. Based on the analysis of about 30 000 km of geophysical and geological data, some layer-blocks in the Nansha micro-plate can be divided as Nansha ultra-crustal layer-block, Zengmu crustal layer-block, Nanwei （Rifleman bank）-Andu （Ardasier bank） and Liyue （Reed bank） North Palawan crustal layer-blocks, Andu-Bisheng and Liyue-Banyue basemental layer-blocks. The basic characteristics of the basemental layer-blocks have been dicussed, and three intra-plate basin groups are identified. The intra-plate basins within Nansha micro-plate can be divided into three basin groups of Nanwei- Andu, Feixin-Nanhua, and Liyue-North Palawan based on the different geodynamics. In the light of pluralistic geodynamic concept, the upheaving force induced by the mid-crust plastic layer is proposed as the main dynamical force which causes the formation of the intra-plate basins within the Nansha micro-plate. Finally, models of a face-to-face dip-slip detachment of basemental layerblock and a unilateral dip-slip-detachment of basemental layer-block are put forward for the forming mechanisms of the Nanwei Andu and Liyue-North Palawan intra-plate basin groups, respectively.

Non-equilibrium turbulent phenomena in transitional flat plate boundary-layer flows

Many recent laboratory experiments and numerical simulations support a non-equilibrium dissipation scaling in decaying turbulence before it reaches an equilibrium state.By analyzing a direct numerical simulation(DNS)database of a transitional boundary-layer flow,we show that the transition region and the non-equilibrium turbulence region,which are located in different streamwise zones,present different non-equilibrium scalings.Moreover,in the wall-normal direction,the viscous sublayer,log layer,and outer layer show different non-equilibrium phenomena which differ from those in grid-generated turbulence and transitional channel flows.These findings are expected to shed light on the modelling of various types of non-equilibrium turbulent flows.

Hydroelastic Response of A Circular Plate in Waves on A Two-Layer Fluid of Finite Depth

The hydroelastic response of a circular, very large floating structure(VLFS), idealized as a floating circular elastic thin plate, is investigated for the case of time-harmonic incident waves of the surface and interfacial wave modes, of a given wave frequency, on a two-layer fluid of finite and constant depth. In linear potential-flow theory, with the aid of angular eigenfunction expansions, the diffraction potentials can be expressed by the Bessel functions. A system of simultaneous equations is derived by matching the velocity and the pressure between the open-water and the platecovered regions, while incorporating the edge conditions of the plate. Then the complex nested series are simplified by utilizing the orthogonality of the vertical eigenfunctions in the open-water region. Numerical computations are presented to investigate the effects of different physical quantities, such as the thickness of the plate, Young’s modulus, the ratios of the densities and of the layer depths, on the dispersion relations of the flexural-gravity waves for the two-layer fluid. Rapid convergence of the method is observed, but is slower at higher wave frequency. At high frequency, it is found that there is some energy transferred from the interfacial mode to the surface mode.

低能见度下GYOLOv5-SPD算法的车牌检测

车牌自动检测技术是构建智慧城市、加强交通管理等方面的重要内容。目前车牌检测技术正在逐步完善,但对于光照条件过低、雨天、雪天等能见度极低的气候环境下所拍摄的车牌照片,车牌检测技术还处于一个相对落后的水平。本文在中国城市停车数据集(CCPD)中能见度极低的车牌图像的基础上利用添加了伽玛(Gamma)变换的你只需看一次(YOLO)v5s模型与空间到深度层及无步长卷积层(SPD-Conv)进行融合用于车牌检测,将低能见度条件下的车牌视为小物体进行检测,目的是最大限度地识别其特征以提高精度。实验结果表明,本文用到的方法在车牌定位检测阶段达到了99.68%的召回率,在低能见度条件下对车牌的定位检测相较其他算法确实有一定的优势。

Modified Layer-Removal Method for Measurement of Residual Stress in Pre-stretched Aluminium Alloy Plate

Residual stress is one of the factors affecting the machining deformation of monolithic structure parts in the aviation industry. Thus, the studies on machining deformation rules induced by residual stresses largely depend on correctly and efficiently measuring the residual stresses of workpieccs. A modified layer-removal method is proposed to measure residual stress by analysing the characteristics of a traditional, layer-removal method. The coefficients of strain release are then deduced according to the simulation results using the finite element method （FEM）. Moreover, the residual stress in a 7075T651 aluminium alloy plate is measured using the proposed method, and the results are then analyzed and compared with the data obtained by the traditional methods. The analysis indicates that the modified layer-removal method is effective and practical for measuring the residual stress distribution in pre-stretched aluminium alloy plates.

XTEM STUDY ON ION PLATED STAINLESS STEEL MULTI-LAYER FILMS

In this paper, the cross sectional microstructure and crystal structure of ion plated multi layer films of stainless steel (1Cr18Ni9Ti ) were studied by cross sectional transmission electron microscopy (XTEM). The results show that ion plated stainless steel multi layer films are fine grained double phase steel films of austenites and ferrites.Cross section film growing microstructures can be divided into three zones: fine equiaxed crystals, fine columnar crystals and coarse columnar crystals. Interfaces in multi layer films can promote fine grained growing and interrupt columnar grained growing,and improve properties of film materials.

A novel LDMOS with a junction field plate and a partial N-buried layer

A novel lateral double-diffused metal–oxide semiconductor（LDMOS） with a high breakdown voltage（BV） and low specific on-resistance（Ron.sp） is proposed and investigated by simulation. It features a junction field plate（JFP） over the drift region and a partial N-buried layer（PNB） in the P-substrate. The JFP not only smoothes the surface electric field（E-field）, but also brings in charge compensation between the JFP and the N-drift region, which increases the doping concentration of the N-drift region. The PNB reshapes the equipotential contours, and thus reduces the E-field peak on the drain side and increases that on the source side. Moreover, the PNB extends the depletion width in the substrate by introducing an additional vertical diode, resulting in a significant improvement on the vertical BV. Compared with the conventional LDMOS with the same dimensional parameters, the novel LDMOS has an increase in BV value by 67.4%,and a reduction in Ron.sp by 45.7% simultaneously.

不锈钢双极板涂层-TiO_(2)薄膜的导电耐腐蚀行为研究

为了提高燃料电池金属双极板的导电耐腐蚀性,本文采用原子层沉积(ALD)工艺,在不锈钢316L上制备了TiO_(2)纳米薄膜,对比了不同加热温度以及基板加热与否时薄膜的导电耐腐蚀性能。结果表明,当加热250℃且基板不加热时,0.84 V恒电位腐蚀24 h,双极板涂层-TiO_(2)薄膜的电流密度最小,为1×10^(-10)A/cm^(2),且腐蚀前后接触电阻相对较小,导电和耐腐蚀性能均表现优异。通过XPS分析腐蚀前后薄膜表面的成分结构,发现二氧化钛保持了较稳定的结构,接触电阻增大主要源于表面C的氧化。

Numerical Analysis of the Structure of High-Strength Double-Layer Steel Plate Concrete Shaft by Drilling Method of Water-Bearing Weak Rock Formation

In order to ensure the safety of coal mine shaft construction, a double-layer steel plate concrete composite shaft wall structure was proposed. However, fewer studies were conducted on this structure, which made engineers too confused to fully recognize its feasibility of this structure. Hence, based on the previous experimental research on the Taohutu mine construction project in Ordos in Inner Mongolia, this research paper aims to provide a widely deep numerical analysis by the usage of the finite element software, in fact, to establish the corresponding numerical analysis model and make a comparison with the experimental data to get the rationality of the verified model. The influence of the composite characteristics of the steel plate and concrete on the ultimate bearing capacity and stress field of the shaft wall structure is studied here through the method of multi-factor analysis. Also, the optimal design scheme of the double-layer steel plate and concrete composite shaft wall structure is proposed in this research paper.

爆炸焊接制备铝-钛复合板工艺研究

开发了1060铝/TA2钛直接爆炸复合新工艺,研究装药量、间隙距离和垫板等参数对复合效果的影响。结果表明:装药量和布药方式对铝-钛板复合强度有明显影响,结合面剪切强度随装药量增多而先增加后降低,分析对比后确定了装药量、间隙距离和垫板形式;爆炸焊接时对6种工艺参数制备的铝-钛复合板结合性能进行分析对比,确定了适宜的焊接参数,进一步优化垫板缓冲层和阶梯布药方式,生产的大规格铝-钛复合板有效区结合率达到100%,批量生产合格,复合质量和结合强度优良,掌握了大规格铝钛直接爆炸复合的工艺技术。

化学镀Ni-P镀层耐蚀性的研究进展

文章通过介绍化学镀Ni-P反应机理、耐蚀性机理和镀层封孔技术等理论知识,同时对化学镀Ni-P技术的稀土催化、多元金属共沉积和多层复合三大趋势进行了归纳,并对化学镀Ni-P技术未来的发展进行了展望。