基于有限条带的厚/薄板矩形通用单元

基于两广义位移梁理论,利用解析试函数来建立厚/薄梁单元的横向位移、转角位移、曲率、剪应变等位移模式,构造出厚/薄梁通用单元.应用有限条带,将厚/薄梁单元的位移模式应用于厚/薄板矩形弯曲单元,直接构造出单元的横向位移、转角、曲率、剪应变,导出了单元的刚度矩阵和结点等效力,编制了计算程序,进行了数值计算和比较,结果表明,所研究的单元不出现剪切闭锁且精度较好.

基于语料库的汉英“厚/薄”语义拓展对比分析

文章从认知语言学视角出发,基于语料库对汉英“厚/薄”语义拓展路径进行对比分析。研究表明:源于空间维度的汉英“厚/薄”可以通过隐喻和转喻机制拓展语义。在概念隐喻机制作用下,源域被投射到四个相同的目标域,分别是“数量/密度”“感官”“程度”和“情感/关系”,说明汉英“厚/薄”语义拓展路径具有普遍性。同时,二者还具有一定的差异性,原因主要在于文化模型的差异。文章在一定程度上证明了空间维度词语义拓展路径普遍性与差异性理论框架的合理性。

英汉“厚/薄”空间隐喻拓展的普遍性与差异性

本文从认知语义学角度出发,对英汉“厚/薄”的空间义和隐喻义进行了对比分析。研究发现,英汉空间量度形容词“厚/薄”的空间引申义存在普遍性和差异性的特征,普遍性表明空间是人类感知事物的基础,而差异性可归因于文化和认知体验的不同。

Theoretical analysis of minimum metal foil thickness achievable by asymmetric rolling with fixed identical roll diameters

A novel approach is proposed for computing the minimum thickness of a metal foil that can be achieved by asymmetric rolling using rolls with identical diameter. This approach is based on simultaneously solving Tselikov equation for the rolling pressure and the modified Hitchcock equation for the roller flattening. To minimize the effect of the elastic deformation on the equal flow per second during the ultrathin foil rolling process, the law of conservation of mass was employed to compute the proportions of the forward slip, backward slip, and the cross shear zones in the contact arc, and then a formula was derived for computing the minimum thickness for asymmetric rolling. Experiment was conducted to find the foil minimum thickness for 304 steel by asymmetric rolling under the asymmetry ratios of 1.05, 1.15 and 1.30. The experimental results are in good agreement with the calculated ones. It was validated that the proposed formula can be used to calculate the foil minimum thickness under the asymmetric rolling condition.

宪法范畴、宪法理论的建构与宪制的维系

法学家与政治学家在理解问题与思考方式上的差异,导致他们对宪法的理解也不同。图施奈特的厚宪法/薄宪法范畴与他的大众主义宪法理论的缺陷在于,在一个没有健全民主制度的国家,无法实施;佩里的第一宪法/第二宪法范畴与宪法原则第一的宪法解释理论无法解决传统宪法原则与新的宪法需求之间的矛盾,因而不适用于社会转型国家;尼诺的历史宪法/理想宪法的范畴与法院裁决正当性和个体行为正当性推理的理论,在逻辑上是一种循环论证,并且容易给他国以干预内政的机会;芬恩的法律宪法/公民宪法范畴与公民教育理论对于尚未建立司法审查制度的国家是本末倒置;立法意义上的宪法/司法意义上的宪法这一范畴的提出,可以有效地解决上述诸范畴与理论中的理论问题与现实问题,并有利于作为制度的宪法的实施与维系。

Current blockade mechanism for DNA translocation through solid-state nanopore with different membrane thickness

The current blockade mechanism for λ -DNA translocation under electrical field is investigated through solid-state nanopores with different pore thicknesses. The conductance of a nanopore system mainly consists of the contribution of the pore and access region, and the latter becomes dominant when the nanopore thickness gradually decreases to atomic layer thickness. Based on the existing model of nanopore resistance, a simplified model which describes the relative current blockade during the X-DNA translocation through the nanopores is deduced to quantitatively present the relationship between nanopore thickness and relative current blockade. Results show that the relative current blockade is effectively increased by reducing the nanopore diameter but it decreases with the decreasing nanopore thickness. A two-stage schematic is proposed to increase the relative current blockade by setting a much smaller resistance region. Experimental results show a 21. 9% increase in the relative current blockade with the proposed schematic.

Electrochemical oxidation of reactive brilliant orange X-GN dye on boron-doped diamond anode

In this study,the electrochemical oxidation of reactive brilliant orange X-GN dye with a boron-doped diamond(BDD)anode was investigated.The BDD electrodes were deposited on the niobium(Nb)substrates by the hot filament chemical vapor deposition method.The effects of processing parameters,such as film thickness,current density,supporting electrolyte concentration,initial solution pH,solution temperature,and initial dye concentration,were evaluated following the variation in the degradation efficiency.The microstructure and the electrochemical property of BDD were characterized by scanning electron microscopy,Raman spectroscopy,and electrochemical workstation;and the degradation of X-GN was estimated using UV-Vis spectrophotometry.Further,the results indicated that the film thickness of BDD had a significant impact on the electrolysis of X-GN.After 3 h of treatment,100%color and 63.2%total organic carbon removal was achieved under optimized experimental conditions:current density of 100 mA/cm2,supporting electrolyte concentration of 0.05 mol/L,initial solution pH 3.08,and solution temperature of 60°C.

Hydraulic bulging process with axial feedings and strain field of U-shaped metal bellows

Based on the traditional hydraulic bulging process,an improved hydraulic bulging process with axial feeding in the bulging process was proposed.The finite element simulation and experiment of bellows formed by the traditional and improved hydraulic bulging processes were conducted.The grid strain measurement system analysis results of strain and wall thickness distribution of the metal bellows,obtained from simulation and experiment,show that the maximum thinning rates of the wall thickness under the traditional and improved processes were 15%and 10%,respectively.And the wall thickness distribution of the metal bellows formed with improved process was more uniform.The strain values from the root to crown of the waveform increased gradually.However,the strain values were smaller than those of traditional process due to the axial feeding of the improved process in bulging process.

Effect of the Thickess on Color of Porcelain Laminate Veneer

Objective : To evaluate the color change of the two-layer porcelain laminate veneer after adding veneering porcelain of different thickness to the 0. 2 mm thick aluminum oxide. Methods : Ten aluminum oxide disks were randomized into 2 groups. Each of five disks was veneered with Vita Lumin Shade 54 porcelain of thickness 0/0.4 mm and 0. 6 mm respectively. The L'a'b* color notations of the substrate covered with nan-veneered disks and 2 thickness porcelain veneered disks were measured separately and the color differences (AE) were calculated. Results ?Statistically significant differences in color coordinates of dark substrates were recorded after the substrate was covered by an aluminum oxide disk and also after the addition of veneering porcelain to the aluminum oxide disks in group 1 (P=0. 000 2) and group 2(P=0. 007 5) and between 2 groups (P=0. 000 1). Conclusion -The ability of masking underlying discoloration was increased and shifted to gray when the thickness of veneering porcelain increased.

Effect of plastic deformation on diffusion-rolling bonding of steel sandwich plates

Diffusion bonding is one of the most important techniques for composite materials, while bonding temperature, holding time,and rolling reduction are the key parameters that affect the bonding strength of sandwich plates. To study the effect of plastic deformation on the bonding strength, laboratory experiments were carried on a Gleeble Thermal Simulator to imitate the diffusion-rolling bonding under different reductions for steel sandwich plates. The bonding strength and interlayer film thickness were measured, and the element diffusion was analyzed using line scanning. The relationship between the bonding strength and “diffused interlayer” thickness was investigated. It has been found that the bonding strength increases with reduction, whereas the interlayer film thickness decreases gradually as the reduction increases. The diffusion under plastic deformation is obviously enhanced in comparison with that of nil reduction. The mechanism of plastic deformation effect on the diffusion bonding and related models have been discussed.

Thin-bed thickness calculation formula and its approximation using peak frequency

Quantitative thickness estimation below tuning thickness is a great challenge in seismic exploration. Most studies focus on the thin-beds whose top and bottom reflection coefficients are of equal magnitude and opposite polarity. There is no systematic research on the other thin-bed types. In this article, all of the thin-beds are classified into four types： thin-beds with equal magnitude and opposite polarity, thin-beds with unequal magnitude and opposite polarity, thin-beds with equal magnitude and identical polarity, and thin-beds with unequal magnitude and identical polarity. By analytical study, an equation describing the general relationship between seismic peak frequency and thin-bed thickness was derived which shows there is a Complex implicit non-linear relationship between them and which is difficult to use in practice. In order to solve this problem, we simplify the relationship by Taylor expansion and discuss the precision of the approximation formulae with different orders for the four types of thin-beds. Compared with the traditional amplitude method for thin-bed thickness calculation, the method we present has a higher precision and isn＇t influenced by the absolute value of top or bottom reflection coefficient, so it is convenient for use in practice.

Bearing mechanism and thickness optimization of ore roof in bauxite stope

Based on the elastic thin plate theory,the main law of the ore roof failure was analyzed and the formula of the ore roof thickness was deduced.The results show that the tensile stress in the roof center accounts for the roof failure.According to the limit failure conditions of the point,the formula of the ore roof thickness was derived.Taking No.10 stope of a bauxite mine as an engineering case,the optimal thickness of the ore roof was 0.36 m.The safety factor was taken as 1.3,therefore the design thickness was 0.5 m.In the whole industrial test process,the dynamic alarm devices did not start the alarm and the ore roof was not damaged.Compared with other stopes under similar conditions,its thickness was reduced by 0.1-0.3 m.The recovery rate of the ore roof was increased by 16.7%-37.5%.

Effect of Film Thickness on Properties of a-Si∶H Films

The a-Si∶H films with different thickness smaller than 1 μm were deposited by plasma enhanced chemical vapor deposition (PECVD) under the optimum deposition conditions. The effect of different thickness on film properties is analyzed.The results show that,with the increase of the film thickness,the dark conductivity, photoconductivity and threshold voltage increase, the optical gap and peak ratio of TA to TO in the Raman spectra decrease, the refractive index keeps almost constant, and the optical absorption coefficient and current ratio of on/off state first maximize and then reduce.

Numerical analysis of bump foil bearings without nominal radial clearance

Bump foil bearings without nominal radial clearance were analyzed. An air film thickness model and a bearing theoretical analytical model were developed accounting for air compressibility and foil deformation. To analyze hydrodynamic characteristics of bump foil bearings with different operating eccentricities, the air film thickness equation and Reynolds equation were coupled through pressure and solved by Newton-Raphson Method (NRM) and Finite Difference Method (FDM). The characteristics of an bump foil bearing model were discussed including load carrying capacity, film thickness and pressure distributions. The results of simulation show that bump foil bearing without nominal radial clearance can provide better stability and greater load capacity. This numerical analytical method also reveals a good convergence in numerical calculation.

Drum instability of thinning spinning ultra thin-walled tubes with large diameter-to-thickness ratio

In order to explore drum instability problems of thinning spinning ultra thin-walled tubes with large diameter-to-hickness ratio, experiments of thinning spinning ultra thin-walled tubes with different clearances between the mandrel and the tube were carried out. The phenomena of drum instability were analyzed. Drum instability mechanism was studied. The important influence of the mandrel-locked ring on stable thinning spinning was found. Besides, two important parameters, namely drum ratio and drum stiffness, were proposed to characterize the drum instability of spinning ultra thin-walled tubes with large diameter-to-thickness ratio. What's more, numerical simulations were applied to explore the influences of different clearance ratios and diameter-to-thickness ratios on the drum instability. As a result, it is found that the mandrel-locked ring is the key to the stability and precision of spinning; drum ratio can reflect the degree of the deformation of the tubes; drum stiffness is a comprehensive index to measure the influences of the tube's own parameters on the spinning instability; both the clearance ratio and diameter-thickness ratio have significant influences on the drum ratio and drum stiffness.

Treating dye wastewater by TiO_2 coated on coal cinder

We investigated the photocatalytic degradation of dye wastewater by using titanium dioxide （TiO2） coated on a coal cinder. The coal cinder was used as the carrier, with a thin film of TiO2 coated on it by using the sol-gel method. Using the Congo red as the model pollutant for dye wastewater, we studied the decolorization efficiency, and effects of TiO2 film thickness and roasting temperature on the efficiency. We also evaluated the recycling and regeneration of the immobilized TiO2 （TiO2/cinder）. Results show that the decolorization rate of Congo red solution was more than 98% after 2.h treatment when we used TiO2/cinder calcined at 500 ℃ for 2 h and coated four times as the photocatalyst. At the same time, the TiO2/cinder remained high catalytic activity after being reused and regenerated for many times.

Preparation and Characterization of Electron-Beam Evaporated Cu-lnSe Thin Films Using Two Stage Processes

CIS （Cu-InSe） thin films were prepared onto glass substrate by the two stage process--generally called bilayer process. At first, Cu layer was deposited onto glass substrate by electron beam evaporation technique and then InSe single layer was deposited on the resulting Cu layer to produce CIS thin film. XRD （X-ray diffraction） analysis revealed that deposited film has an amorphous nature. Electrical resistivity measurements were carried out as a function of temperature during heating and cooling cycles in air. The heating and cooling cycles of the sample are almost reversible after successive heat-treatment in air. In order to consider the influence of the InSe upper layer on the optical properties, the thickness of the InSe upper layer in the CIS films was varied from 50 to 150 nm. Analysis of the transmittance and reflectance spectra, recorded in the wavelength range of 400-1,100 nm, revealed that the CIS films have high absorption coefficient of-104 cm1. The direct band gap varies from 1.40 to 1.22 eV. The refractive index, the extinction coefficient and the dielectric constant of the CIS films depend on the film thickness.

Correlating Photovoltaic Performance of Dye-Sensitized Solar Cell to the Film Thickness of Titania via Numerical Drift-Diffusion Simulations

The thickness of TiO2 film is vital to realize the optimization on photovoltaic performance of dye sensitized solar cells （DSSCs）. Herein, the process of charge separation in DSSCs was simulated by using a drift-diffusion model. This model allows multiple-trapping diffu- sion of photo-generated electrons, as well as the back reaction with the electron acceptors in electrolyte, to be mimicked in both steady and non-steady states. Numerical results on current-voltage characteristics allow power conversion efficiency to be maximized by varying the thickness of TiO2 film. Charge collection efficiency is shown to decrease with film thick- ness, whereas the flux of electron injection benefits from the film thickening. The output of photocurrent is actually impacted by the two factors. Furthermore, recombination rate constant is found to affect the optimized film thickness remarkably. Thicker TiO2 film is suitable to the DSSCs in which back reaction is suppressed sufficiently. On the contrary, the DSSCs with the redox couple showing fast electron interception require thinner film to alleviate the charge loss via recombination. At open circuit, electron density is found to decrease with film thickness, which engenders not only the reduction of photovoltage but also the increase of electron lifetime.

Determination of Optical Constant and Thickness for Thin Film by Using Improved FTM

A new method to determine the optical constant and thickness of thin films is proposed. Based on the Fresnel’s optical expression, the improved flexible tolerance method(FTM) is employed in the case of a digital model of thin film to fit the curve of measured reflectance spectrum. The simulation results show a satisfactory correlation of the optical constant with the thickness of the target film. By taking the influence of nonlinear condition into account as well as more direct and indirect limitation, the precision and value-searching efficiency have been improved. Furthermore, the problem of dimension degradation, which exists in “Downhill Simplex”, has been successfully avoided. No initial input is needed for the procedure of optimization to achieve optical solution, which makes the whole processing of value calculation much more convenient and efficient.

Measurement of thickness and heat transfer coefficient of water film out of tube in an evaporative air cooler

Thickness of falling water film out of tubes is one of critical factors of heat transfer of evaporative air cooler. A new method of resistance measurement was developed to measure thickness of the film. When the resistance probe on the tip of micrometer touches the surface and bottom of the film, two corresponding sudden reductions of resistance occurs, and the difference of two graduations on the micrometer displays the thickness of the film. The film thickness of eleven angles was measured in five kinds of water flows and results varies from 0.8933mm to 1.7233 mm. Mean thickness and mean heat transfer coefficient of the film out of the tube was calculated.