Effect of the thickness of the Ru-coating on a counter electrode on the performance of a dye-sensitized solar cell

A ruthenium (Ru) catalytic layer was assessed as the counter electrode (CE) in dye sensitized solar cells (DSSCs) by examining the effect of the Ru thickness on the DSSC performance. Ru films with different thicknesses (34, 46, 69 and 90 nm) were deposited on glass/fluorine-doped tin oxide (FTO) substrates as the CE by atomic layer deposition (ALD) at 250 °C using RuDi as the precursor and O₂ as the reaction gas. Finally, a 0.45 cm² DSSC of glass/FTO/TiO₂/dye(N719)/electrolyte(C6DMII, GSCN)/Ru CE structure was prepared. The properties of the DSSCs were examined by field emission scanning electron microscopy (FESEM), four-point-probe, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), current-voltage (I–V), incident photon-to-current conversion efficiency (IPCE), and dark current measurements. FESEM showed that the crystallized Ru films had been deposited quite uniformly and conformally on the glass/FTO surface. The sheet resistance of the Ru film decreased with increasing Ru thickness. CV profiling revealed an increase in catalytic activity with increasing film thickness. The charge transfer resistance at the interface between the Ru-coated CE and electrolyte decreased with increasing Ru thickness. I–V profiling showed that the energy conversion efficiency was increased up to 3.40 % by increasing the Ru thickness. Moreover, the IPCE and dark current results showed the efficiency of the Ru-coated CE was comparable to that of a conventional platinum (Pt) CE.     

Improvement of the adhesion of a ceramic coating on a ceramic substrate

The structure and adhesion of an alumina coating on a ceramic substrate with NiCrAlY alloy bond coating was investigated by heating at 1573 and 1673 K in the air. Phases of NiO, NiCrO₃, NiAl₂O₄, αAl₂O₃, and Ni were revealed in a 100 μm thick bond coating on heating at 1573 and 1673 K. A veined structure was also detected in the coating heated at 1573 K. The adhesion strength of the coating was improved and reached approximately 20 MPa on heating at 1573 and 1673 K for 14.4 ks in air although the strength of the as-sprayed coating was only 2 MPa. The improvement of adhesion strength may arise from the formation of NiAl₂O₄ with a spinel structure at the interfaces of the top coating/bond coating/substrate coating system. The adhesion strength of the coating improved on decreasing the bond coating thickness and reached approximately 45 MPa for a 20 μm thick bond coating which was heated at 1673 K. Only NiAl₂O₄ oxide was formed in the bond coating.     

某输气管线弯管开裂原因分析

某弯管发生刺漏现象,为明确该弯管开裂原因及失效机理,本文采用宏观分析、理化性能、微观分析、腐蚀模拟试验等手段对其进行分析研究。结果表明：该弯管开裂失效机理为硫化氢应力腐蚀,失效的主要原因为,该弯管热煨弯工艺不合理,导致弯曲段产生大量的马氏体组织,马氏体组织硬度较高,对硫化氢应力腐蚀开裂较为敏感;该弯管输送的天然气中含有游离水和硫化氢,硫化氢溶于游离水,对金属基体产生应力腐蚀作用,导致弯管发生开裂。     

On the interface debond at the edge of a thin film on a thick substrate

The failure by debonding of 400 nm Al thin films on 152 μm-thick polyimide substrates has been studied in uniaxial tension experiments. To explain the edge debond of the Al film, the shear stress field along the film–substrate interface is determined. An analytical solution for the stress field exhibits a square root singularity near the free edges. The associated stress intensity factor is calculated in closed form by an asymptotic analysis. For a given loading, the stress intensity factor decreases with increasing length-to-thickness ratio of the film, and with decreasing film-to-substrate stiffness ratio. Governed by a single, dimensionless parameter, these trends are reported quantitatively in the form of a plot. Close correspondence is found for the interfacial shear stresses predicted by the presented method and by a finite element analysis.     

Kelvin-Helmholtz instability on the charged surface of a liquid with finite thickness on a hard bottom

Analytical calculations of the first order of smallness show that the size of an increment of the Kelvin-Helmholtz instability depends on the thickness of the liquids. Upon growth of the Weber and Tonks-Frenkel parameters, the instability increment increases.     

Estimation of the influence of the pulse-load parameter on a decreasing static stress in a steel band

The theoretical study of the impact of the pulse-load characteristics on the relaxation of the residual stress in materials with the help of mathematical modeling is completed.     

产业化影响下高校办学理念的思考

高等教育已经是一种产业，我们必须按产业化的规律来运作；高等教育是一种特殊的产业，我们必须凸现高等教育的特殊地位和特殊功能。以此为前提，在我们思考产业化影响下的高校办学理念时，应特别关注高等教育功能的前瞻性和先导性，强调以人为本，科学思维，体现哲学强校，在表述上要有特色和创新。     

Experimental observation of a soliton-like moving swell on the surface of a palladium-hydrogen alloy

Upon additional saturation of a PdH_0.1 alloy with hydrogen under highly nonequilibrium conditions, moving coherently conjugate undulatory swells, (whose shape and character of motion resemble those of solitary translational waves—solitons) on the surface have been for the first time fixed and recorded on video tape. Based on modern concepts about the metal-hydrogen systems, the observed soliton-like moving swell and the mechanism of its formation and motion have been discussed. Emphasis has been placed on the fact that the incipient formation of soliton-like coherent moving swells is a special previously unknown mechanism of relaxation and leveling-off of internal stresses in metal-hydrogen alloys.     

Investigation of the tarnish on the surface of a panda gold coin

In natural environment, tarnish was observed on the surface of historic and contemporary gold coins in several countries. Few years after the emergence of panda gold coins, several red spots were appeared on the surface. To identify the stains and to examine the spots, optical microscope （OM）, scanning electron microscope （SEM）, electron microprobe analysis （EMPA）, X-ray photoelectron spectroscopy （XPS）, and X-ray diffraction （XRD） were used. It was found by microscopic observation that the stain has a dark blue central area surrounded by a large area with a nuance of colors from brown to red. Red spots usually contain holes in the center, which are distributed along the forging stress zones formed in the struck process. From the surface analyses using EMPA, sulfur and silver are detected besides gold, and the contents of Ag and S at the tarnish part are higher than those at the other part. Furthermore, distributions of Ag and S are correlated with the morphology of stains. XPS shows that components of stains are Ag2S and Ag2SO4 and the former is much predominant. These results are confirmed using XRD analysis. Accelerated tarnish test of gold in an atmosphere containing sulfur compound proves that the similar phenomenon appears when a small amount of silver is present on the surface of gold. It can be concluded that the occurrence of tarnish stains is caused by the presence of Ag and S.     

烟气轮机叶片断裂原因分析

某炼化厂烟气轮机一动叶片断裂引起停机事故.通过断口宏观、微观观察和叶片金相检验对叶片断裂原因进行分析,结果表明:叶片断裂性质为微动疲劳,叶片榫头与轮盘榫槽装配不良导致局部应力过大产生微动磨损是引起疲劳断裂的主要原因.     

Effect of decarburizing on the failure of a shock-absorber cylinder

Defects arising due to violations of the regime of heat treatment of metals can worsen the serviceability and can damage expensive equipment. This especially concerns objects of the aircraft industry. The authors consider the causes of failure of shock-absorber cylinders of the landing gear of an aircraft.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 10–12, May, 1995.     

Influence of Carbon on the Microstructure of a Fe-Mn-Si-Cr-Ni Alloy

The influence of the addition of C to the Fe-Mn-Si-Cr-Ni base material is investigated at room temperature. Steel samples were deformed during a tensile experiment up to a strain of 17%. Light optical microscopy (OM) and x-ray diffraction (XRD) gave information about the different micro-structural phases that exist in the deformed and the undeformed alloys. The evolution of the defect structure is followed by positron annihilation techniques such as Doppler broadening of annihilation radiation spectroscopy (DBAR) and the positron annihilation lifetime spectroscopy (PALS). During deformation a martensitic ε-phase is induced. The size of the martensite plates increases with increasing deformation.     

Synthesis of a polypyrrole film on a non-conducting substrate; the influence of the oxidant and acid concentration

Thin films of conducting polypyrrole are deposited on a non-conducting substrate by dipping the substrate in a pyrrole solution and subsequently in an oxidising solution containing Fe(ClO₄)₃ and HClO₄. In this last step pyrrole is polymerised by Fe³⁺. Calculations on the influence of the acid concentration on the Fe³⁺ hydrolysis equilibria are in good agreement with UV/VIS and pH measurements. These calculations and experiments in which HClO₄ is replaced by LiClO₄, show that the polymerisation rate of pyrrole is determined by the perchlorate concentration and not by the acid concentration. We conclude that the perchlorate ions promote the dimerisation of the radical cations by reducing the electrical repulsion between the radical cations; therefore the dimerisation of the radical cations is the rate-determining step.     

On the thermally induced cracking of a segmented coating deposited on the outer surface of a hollow cylinder

In this work, the thermally induced cracking behavior of a segmented coating has been investigated. The geometry under consideration is a hollow cylinder with a segmented coating deposited onto its outer surface. The segmentation cracks are modeled as a periodic array of axial edge cracks. The finite element method is utilized to obtain the solution of the multiple crack problem and the Thermal Stress Intensity Factors (TSIFs) are calculated. Based on dimensional analysis, the main parameters affecting TSIFs are identified. It has been found that the TSIF is a monotonically increasing function of segmentation crack spacing. This result confirms that a segmented coating exhibits much higher thermal shock resistance than an intact counterpart, if only the segmentation crack spacing is narrow enough. The dependence of TSIF on some other parameters, such as normalized time, segmentation crack depth, convection severity as well as material constants, has also been discussed.     

A Study on the Effect of Bath Composition on the Internal Stress of a Palladium Electrodeposit

The effects of bath composition on the internal stress of palladium electrodeposits are studied in neutral media with Pd(NH₃)₂Cl₂, K₃C₆H₅O₇, (NH₄)₂C₂O₄ and the additives of the mixture of the synthesized products of nicotinic acid and nicotiamide (NANA), pyridine-3-sulfonic acid(PSA), α-furane formic acid(FF) and cetyl trimethyl ammonium bromide(CTMAB). The results show that the internal stress of electrodeposits is quite changeable at the beginning of electrodeposition later becoming stable gradually. Deposits obtained from pulse electrodeposition have lower stress than that from direct current. After electrodeposition, all the deposits keep in tensile stress which increases with time.     

在纳米压入仪上进行悬臂梁法测量弹性模量的影响因素分析

对在纳米压入仪上进行悬臂梁法测量弹性模量的主要影响因素进行了综合分析,主要包括加载系统悬置弹簧刚度、压头压入、梁沿截面宽度方向挠曲、梁支座附加挠曲等影响。在考虑这些因素的基础上,得到了悬臂梁的有效挠度,利用有效挠度与载荷之间的关系,评价悬臂梁材料的弹性模量。对单晶硅(100)悬臂梁试样进行了实验,得到其弹性模量为155GPa±9.5%GPa,与参考文献值符合较好。表明在纳米压入仪上进行悬臂梁法测量,只有综合这些影响因素后,才能获得有效、准确的弹性模量测量结果。     

焊接滚轮架上工件轴向窜动防窜机理研究

探讨了筒体在焊接中出现轴向窜动的问题和产生轴向窜动的主要原因,分析了对主动轮转速的控制和筒体轴窜位移的调节机理,同时提出了具有位移、速度负反馈的非线性控制方案,并通过相平面法对系统稳定性进行了分析.     

A study on the corner filling in the drawing of a rectangular rod from a round bar

An important characteristic of the shaped drawing process, unlike the wire drawing process, is the corner filling which influences the dimensional accuracy of the product. In this study, therefore, in order to investigate the effect of process variables, such as the reduction in area, the semi-die angle, and the rectangular ratio to the corner filling, the drawings of a rectangular rod from a round bar have been simulated by using the three-dimensional rigid-plastic finite element method (FEM) and an artificial neural network has been introduced to reduce the number of simulations. To verify the results of the study, the experimental investigations were also carried out on real industrial products. According to the results, in the case of the irregular-shaped drawing process the main process variable on the corner filling is the combination of the semi-die angle but for the regular-shaped drawing process, the reduction in area has a significant effect on the corner filling.