Skin temperature measurement method

To improve the accuracy of skin temperature measurements in thermal comfort research,a new measurement method based on a new thermometer is proposed.A platinum film resistance（Pt1000）sensor of the thermometer is welded on a printed circuit board to eliminate the heat loss from the leads and avoid the influence of the surrounding thermal environment.In order to determine the suitable thickness of the board,a steady heat conduction model is established.The simulation results reveal that when the thickness of the board is 0.2 mm,the influence of the surrounding air can be effectively prevented and the skin temperature does not obviously increase.The experimental results of verification show that the maximum measurement error of the skin temperature measured by the thermometer is 0.24 ℃,and the average measurement error of the skin temperature is 0.04 ℃.The proposed method provides an effective and reliable option for the skin temperature measurement in thermal comfort research.

Deformation behavior of A6063 tube with initial thickness deviation in free hydraulic bulging

Experiment on seamless tubes of aluminum alloy A6063 with initial thickness deviation of 0-20% was conducted through a free hydraulic bulging with tube ends free. The influence of initial thickness deviation on the cross-section profile, thickness distribution, maximum internal pressure and maximum radial expansion was investigated. FEM simulation was also performed in order to examine and help explaining the experimental results. The results indicate that the internal pressure and maximum internal pressure appear to be little influenced by the initial thickness deviation, and that the cross-section profile of the bulged tube changes diversely and can not be a perfect circle. The results also suggest that the increase in initial thickness deviation may lead to a remarkable decrease in maximum radial expansion, and a rapid increase in thickness deviation and the center eccentricity of the inner and outer profiles.

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.

A VHF PECVD Micro-Crystalline Silicon Bottom Gate TFT with a Thin Incubation Layer

The incubation layer with amorphous structure between the substrate and crystalline layer may obviously affect the performance for a microcrystalline Si thin film transistor (μc-Si TFT),especially for the bottom gate TFT(BG-TFT).It is found that decreasing the ratio of SiH 4/(H 2+SiH 4) is an effective way to decrease the incubation layer thickness of μc-Si directly deposited by VHF PECVD without any further thermal or laser treatment.Based on the μc-Si with a thin incubation layer,the BG-TFT with Al/SiN x/μc-Si/n+-μc-Si/Al structure is fabricated.The ratio of on-state current to off-state current is up to 106,the mobility is around 0.7cm2/(V·s),and the threshold voltage is about 5V.

Improvement of adhesion properties of TiB_2 films on 316L stainless steel by Ti interlayer films

The periodic [Ti/TiB2]n （n=l, 2, 3） multilayered films were prepared on the substrate of AISI 316L stainless steel by magnetron sputtering to enhance the adhesion of TiB2 films based on the remarkable mechanical performance of layered films. The influence of periods on microstructure, adhesion and hardness of [Ti/TiB2]n multilayered films was studied. X-ray diffraction （XRD） analysis shows that the monolayer TiB2 films exhibit （001） preferred orientation, and the preferred orientation of [Ti/TiB2], multilayered films transfers from （001） to （100） with the increase of periods. The cross-sectional morphology of each film displays homogeneity by field emission scanning electron microscopy （FESEM）. The hardness of the films measured via nanoindention changes from 20 to 26 GPa with the increase of periods. These values of hardness are a bit lower than that of the monolayer TiB2 films which is up to 33 GPa. However, the [Ti/TiB2]n multilayered films present a considerably good adhesion, which reaches a maximum of 24 N, in comparison with the monolayer TiB2 films according to the experimental results.

是“厚”不是“薄”

近年来,不断有既轻又薄的眼镜片投放市场,介绍这类产品的广告随之大增,有的还称为“戴镜者的福音”。“福音”常常见诸报端。例如: 位于西直门立交桥西侧路南的华静眼镜店(西直门外大街34号)新到日本康谊5000电脑验光机和法国康龄超薄茶色镜片,近视在500度至1800度的患者可配制此片,薄度仅为普通镜片的一半。(《北京广播电视》1988年2月3日)薄得只有普通镜片的一半,的确薄。可是再薄的东西在说它的厚薄程度时也得说“厚度”而不说“薄度”。“厚度”是名词,指扁平物上下的距离,还有如表示物体两端距离的名词“长度”,表示物体高低程度的名词“高度”,表示分量的名词“重量”。再短也得说“长度”;再轻也要说“重量”。它们不同于作形容词的“厚、长、高、重”等,作形容词的,有相对的表示负概念的词,“厚”有“薄”,“长”有“短”,“高”有“低”或“矮”,“重”有“轻”,作名词的则没有。

马钢CSP成功轧制出1．95mm耐候钢板

马钢CSP生产线成轧制出1．95mm合格耐候钢板，各项指标兑现率明显提高，尤其是薄度指标尤为突出，为CSP投产以来之最。此举极大地提高了马钢板材的市场占有率。

Minority-Carrier Exclusion Effect in Thin-Film SOI Temperature Sensor

A silicon temperature sensor with a conventional resistor structure is fabricated on thin-film silicon-on-insulator (SOI) substrate.The sensor has very promising characteristics.The maximum operating temperature can reach 550℃ even at a low current of 0.1mA.Experimental results support that the minority-carrier exclusion effect can be strong in the conventional resistor structure when the silicon film is sufficiently thin,thus significantly raising the maximum operating temperature.Moreover,since the structure of the device on thin-film SOI wafer is not crucial in controlling the maximum operating temperature,device layout can be varied according to the requirements of applications.

Establishment of size-dependant constitutive model of micro-sheet metal materials

The inherent mechanism of size effect in micro-sheet material behavior of plastic forming was explained by the surface layer model and theory of metal crystal plasticity. A size-dependant constitutive model based on the surface layer model was established by introducing the scale parameters and modifying the classical Hall-Petch equation. The influence of the geometric dimensions and the grain size on the flow behavior of the material was discussed using the new material constitutive model. The results show that, the flow stress decreases while the sheet metal thickness decreases when the grain size keeps constant, and the micro-sheet metal with a larger grain size is more easily to be influenced by the size effects. The material constitutive model established is validated by the stress-strain curve of the micro-sheet metal with different thicknesses derived from the tensile experiments. The rationality of the material model is verified by the fact that the calculation results are consistent with the experimental results.

Microstructure and mechanical properties of TiN/TiAlN multilayer coatings deposited by arc ion plating with separate targets

TiN/TiAlN multilayer coatings were prepared by arc ion plating with separate targets. In order to decrease the unfavorable macroparticles, a straight magnetized filter was used for the low melting aluminium target. The results show that the output plasmas of titanium target without filter and aluminium target with filter reach the substrate with the same order of magnitude. Meanwhile, the number of macropartieles in TiN/TiAlN multilayer coatings deposited with separate targets is only 1/10-1/3 of that deposited with alloy target reported in literature. Al atom addition may lead to the decrease of peak at （200） lattice plane and strengthening of peak at （111） and （220） lattice planes. The measured hardness of TiN/TiAlN multilayer coatings accords with the mixture principle and the maximum hardness is HV2495. The adhesion strength reaches 75 N.

Growth Rate of a-Si∶H Film Influenced by Magnetic Field Gradient in MWECR CVD Plasma System

The magnetic field profiles,which are produced by three ways in the deposition chamber and plasma chamber of single coil divergent field MWECR CVD system,are investigated.The magnetic field gradient of these magnetic field profiles is obtained quantitatively by using Lorentz fit.The results indicate that the gradient value of the magnetic field profile near by the substrate,which is produced by a coil current with 137.7A if a SmCo permanent magnet is equipped under the substrate holder,is the largest;when the SmCo permanent magnet is taken away,the larger one is produced by the coil current with 137.7A and the smallest one produced by a coil current with 115.2A.High deposition rate of a-Si∶H film is observed near by the substrate with high magnetic field gradient.But uneven deposition rate along the radius of the sample holder is also found by infrared analysis technology when sample is deposited in magnetic field profile,which is produced by the coil current with 137.7A if the SmCo permanent magnet is equipped under the substrate holder.

Growth and Optical Properties of ZnO Films and Quantum Wells

The growth characteristics during metalorganic chemical vapor deposition and optical properties of ZnO films on sapphire （Al2O3） （0001） and （1120） substrates are studied. For the former,the effects of two important growth parameters,i, e. temperature and pressure, are investigated in detail. Due to the large lattice mismatch between the film and the substrate, ZnO nanocrystals are usually obtained. The growth behavior at the film-substrate interface is found to be strongly dependent on the growth temperature,while the growth pressure determines the shape of the nanostructures as they grow. It is difficult to obtain ZnO films that have good quality and a smooth surface simultaneously. Due to the smaller lattice mismatch,the critical thickness of ZnO on the Al2O3 （1120） surface is found to be much larger than that on the Al2O3 （0001） surface. ZnO/MgZnO quantum wells with graded well thicknesses are grown on the Al2O3 （1120） surfaces,and their optical properties are studied. The built-in electric field in the well layer, generated by the piezoelectric effect, is estimated to be 3 × 10^5 V/cm. It is found that growth at low temperatures and low pressures may facilitate the incorporation of acceptor impurities in ZnO.

Deflection and stress of hollow CRCP slab under concentrated vehicle load

Based on the equivalence principle of deflection and stress, the concentrated vehicle load which acts on the center of continuously reinforced concrete pavement （CRCP） is translated into the equivalent half-wave sine load by the Fourier transform. On the basis of this transform and the small deflection theory of elastic thin plates, the deflection and stress formulae of CRCP under the concentrated vehicle load with a hollow foundation are put forward. The sensitivity of parameters is analyzed. The results show that maximum deflection is directly proportional to the concentrated vehicle load and the slab width, and inversely proportional to the lateral bending stiffness and slab thickness. The effects of slab width and thickness are significant with regard to maximum deflection. Maximum stress is directly proportional to the concentrated vehicle load and the slab width as well as inversely proportional to slab thickness. The effect of slab thickness is significant with regard to maximum stress. According to the calculation results, the most effective measure to reduce maximum deflection and stress is to increase slab thickness.

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.

Influence of pyrolysis temperature on ferroelectric properties of La and Mn co-doped BiFeO_3 thin films

Bi0.9La0.1Fe0.95Mn0.05O3 （BLFMO） ferroelectric thin films were fabricated on Pt/Ti/SiO2/Si/ substrates by the sol-gel process at different pyrolysis temperatures. The mass loss of BLFMO powder was investigated by thermo gravimetry analyser （TGA）, and the polycrystalline structure and smooth surface of BLFMO thin films were characterized by X-ray diffraction （XRD） and atomic force microscopy （AFM）, respectively. The remnant polarization （Pr） of the BLFMO films pyrolyzed at 420 ℃ is 21.2 μC/cm2 at the coercive field （Ec） of 99 kV/cm and the leakage current density is 7.1×10-3 A/cm2, which indicates that the BLFMO thin films display relatively good ferroelectric property at this temperature.

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.

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.

Accuracy analysis of plane-strain bulge test for determining mechanical properties of thin films

The effect of a variety of geometrics, initial conditions and material properties on the deformation behavior of thin films in the plane-strain bulge test was systematically scrutinized by performing the finite element analysis, and then the accuracy of the plane-strain bulge test in determining the mechanical properties of thin films in terms of our finite element results was analyzed. The results indicate that although the determination of the plane-strain modulus in the light of the plane-strain bulge equation is fairly accurate, the calculation of the residual stress is not satisfied as expected, especially for low residual stress. Finally, an approach is proposed for analyzing bulge test data, which will improve the accuracy and reliability of this bulge test technique.

Reinforcement by polyurethane to stiffness of air-supported fabric formwork for concrete shell construction

By spraying concrete on inner surface,air-supported fabric structures can be used as formwork to construct reinforced concrete shell structures.The fabric formwork has the finished form of concrete structure.Large deviation from the desired shape of concrete shells still remains as central problem due to dead weight of concrete and less stiffness of fabric formwork.Polyurethane can be used not only as a bonding layer between fabrics and concrete but also as an additional stiffening layer.However,there is little research on mechanical behaviors of the polyurethane shell structure.This paper presents experimental studies on an inflated fabric model with and without polyurethane,including relief pressure tests,vertical loading tests and horizontal loading tests.Experimental results show that the additional polyurethane layer can significantly enhance the stiffness of the fabric formwork.Compared with the experiment,a numerical model using shell layered finite elements has a good prediction.The reinforcement by polyurethane to improve stiffness of air-supported fabric formwork is expected to be considered in the design and construction of the concrete shell,especially dealing with the advance of shape-control.

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.