脂肪酶在负离子化PET表面的单分子层自组装膜研究

研究了脂肪酶分子在表面负离子化聚对苯二甲酸乙二醇酯 (PET)薄膜表面的分子自组装 ,由 AFM和FTIR-ATR等方法研究脂肪酶单分子层膜的表面结构 ;活力测定表明 :脂肪酶 /PET自组装单分子层膜的酶活力表现率约为 2 .

硬质薄膜在建筑装饰中的应用

文章主要介绍了装饰薄膜的种类及其各自的优缺点,并对装饰薄膜在建筑装饰中的应用前景进行了展望。文章指出,新装饰材料的发展方向是绿色装饰材料,而廉价材料表面薄膜化处理是一个很好的方法。在廉价材料表面沉积硬质薄膜,不仅可以使材料表面具有独特的装饰效果,还能使得材料表面具备优良的抗腐蚀、抗磨损及抗氧化性能。

Effect of depressurizing speed on mold filling behavior and entrainment of oxide film in vacuum suction casting of A356 alloy

The effect of depressurizing speed on mold filling behavior and entrainment of oxide film of A356 alloy was studied. Themold filling behavior and velocity fields were recorded by water simulation with particle image velocimetry. The results show thatthe gate velocity first increased dramatically, then changed with the depressurizing speed: the gate velocity increased slowly atrelatively high depressurizing speed; at reasonable depressurizing speed, the gate velocity kept unchanged; while at lowerdepressurizing speed, the gate velocity decreased firstly and then kept unchanged. High gate velocity results in melt falling backunder gravity at higher speed. The falling velocity is the main factor of oxide film entrainment in vacuum suction casting. The designcriterion of depressurizing rate was deduced, and the A356 alloy castings were poured to test the formula. The four-point bend testand Weibull probability plots were applied to assessing the fracture mechanisms of the as-cast A356 alloy. The results illuminate amethod on designing suitable depressurizing speed for mold filling in vacuum suction casting.

Surface characteristics and structure of oxide films containing Ca and P on Ti substrate

The oxide films were obtained in an electrolyte of calcium glycerphosphate (Ca-GP) and calcium acetate (CA) by microarc oxidation (MAO). The oxide films displayed a porous and rough structure on the film surface, and the roughness tended to increase with increasing voltage of microarc oxidation. The oxide film exhibited a uniform coating and tends to be well boned to the substrate. The thickness of oxide films depended on the final voltage at a constant concentration of electrolyte solution. Ca and P were also incorporated into the oxide film during the microarc oxidation process. It was found that the electrolyte of calcium glycerphosphate (Ca-GP) and calcium acetate (CA) was suitable for microarc oxidation to form oxide film containing Ca and P on Ti substrate. The concentration of Ca and P were 11.6 at% and 6.4 at%, respectively, when microarc oxidation was performed in the electrolyte of 0.06 M Ca-GP and 0.25 M CA at current density 50 A/m^2 and final voltage 350 V. The composition of the Ca, P and Ti changed during depth profiling. The crystalline phases were only anatase when final voltage was below 300 V and rutile was presented when voltage was up to 350 V. The microstructure, phase structure and phase composition were investigated by scanning electron microscopy (SEM), atomic force microscope (AFM), energy dispersive X-ray microanalyser (EDX), and X-ray diffraction (XRD).

Fabrication of nanoporous TiO_2 films with novel surface morphology on conducting glass(FTO) substrate

The crystalline structure and surface morphology of TiO2 semiconductor coating play an important role in the conversion efficiency of dye-sensitized solar cells. In order to obtain TiO2 coating with controllable morphology and high porosity, nanoporous TiO2 films were fabricated on conducting glass （FTO） substrates, Ti thin films （1.5-2 gin） were deposited on conducting glass （FTO） substrates via the DC sputtering method, and then electrochemically anodized in NH4F/ethylene glycol solution. The crystalline structure and surface morphology of the samples were characterized by X-ray diffraction （XRD） and field emission scanning electron microscopy （FESEM）, respectively. The influences of anodizing potential, electrolyte composition, and pH value on the surface morphology of nanoporous TiO2 films were extensively studied. The growth mechanism of nanoporous TiO2 films was discussed by current density variations with anodizing time. The results demonstrate that nanoporous TiO2 films with high porosity and three-dimensional （3D） networks are observed at 30 V, when the NH4F concentration in ethylene glycol solution is 0.3% （mass fraction） and the electrolyte pH value is 5.0.

Study on Surface States of Zinc Sulfide Electroluminescence Thin Films

The zinc sulfide electroluminescence(EL) thin film doped with erbium,fabricated by thermal evaporation with two boats,are made and analyzed by the technology of X-ray photoelectron spectroscopy.The information of surface states of the microcrystalline thin films is obtained.The transient EL spectroscopy of the thin film devices is measured and simulated by the formulae of different energy transfer mechanism.The results indicate that the formula of Gaussian line shape can fit well for description of transient EL process of zinc sulfide thin film doped with erbium.It shows that the surface states have important effect on the relaxation peaks during the decay process of EL for the thin film devices.

The Effects of Annealing on the Surface Properties of Titania Films Prepared on Titanium by Micro-Arc Oxidation

Titanium and its alloys are widely used in the aerospace, marine, and biomedical industry due to their unique bulk properties such as high strength-to-weight ratio and melting temperature, good corrosion resistance, and favorable biocom- patibility. However, in some applications, com- ponents made of titanium or titanium alloys exhibit poor wear resistance under stationary or dynamic loading as well as contact corrosion manifested by the relatively negative standard electrode potential （-1.63 V ） . In order to improve the surface properties of titanium and its alloys, several techniques such as PVD （ physical vapor deposition ） /CVD （chemical vapor deposition ） coatings,

A n-Si/CoOx/Ni:CoOOH photoanode producing 600 mV photovoltage for efficient photoelectrochemical water splitting

n-Si,believed as a promising photoanode candidate,has suffered from sluggish oxygen evolution reaction(OER)kinetics and poor chemical stability when exposed to aqueous electrolyte.Herein,CoO_(x)/Ni:CoOOH bilayers were successfully deposited on n-Si substrate by atomic layer-deposition(ALD)and photoassisted electrochemical deposition(PED)for stabilizing and catalyzing photoelectrochemical(PEC)water oxidation.In comparison to the n-Si/CoO_(x)photoanode as reference,the prepared n-Si/CoO_(x)/Ni:CoOOH photoanode upon the optimized PED process presents a much improved PEC performance for water splitting,with the onset potential cathodically shifted to~1.03 V vs.reversible hydrogen electrode(RHE)and the photocurrent density much increased to 20 mA cm^(−2)at 1.23 V vs.RHE.It is revealed that the introduction of Ni dopants increases the work functions of the deposited Ni:CoOOH overlayers,which gives rise to the upward band bending weakened at the n-Si/CoO_(x)/Ni:CoOOH cascading interface while strengthened at the Ni:CoOOH/electrolyte interface(with the band bending shifted from downward to upward),contributing to the decreased and the increased driving forces for charge transfer at the interfaces,respectively.Then,the balanced driving forces at the interfaces would endow the n-Si/CoO_(x)/Ni:CoOOH photoanode with the best PEC performance.Moreover,PED has been evidenced superior to ED to dope Ni into CoOOH with the formed overlayer effectively catalyzing and stabilizing PEC water splitting.

In vitro and in vivo evaluation of porous NiTi alloy modified by sputtering a surface TiO_2 film

A uniform and dense TiO2 film was grown on the surface of porous NiTi shape memory alloys(SMAs) successfully by RF magnetron sputtering.The morphology and composition of the surface film were analyzed by using scanning electron microscopy and X-ray photoelectron spectroscopy.The corrosion resistance measurement proved that the surface modified porous NiTi SMAs exhibit better corrosion resistance and over 25% reduction of Ni ion release in the blood of the rabbits in comparing with the samples without surface modification.Moreover,the biocompatibility,as demonstrated by cell adherence and implant surgery,revealed that the cell adherence and bone tissue inducing capability are respectively enhanced over 1.1-1.2 and 9-10 times by sputtering a uniform TiO2 film on the surfaces of porous NiTi SMAs.