用光纤准直耦合光路测量大气光学湍流

阐述了利用光纤准直器对组成的耦合光路的附加损耗产生的机理,证明大气湍流运动可引起该光路的附加损耗发生随机变化。根据湍流大气光传播原理,推导出了耦合光功率与光路参数和湍流参数关系式。分析表明：实际湍流大气造成的随机附加损耗主要取决于湍流强度。实验验证了利用该光路可在很短的空气间隙内获得湍流强度的变化信息。     

不同蒸煮方式下不同链长脂肪酸对板栗淀粉特性的影响

目的 研究不同蒸煮方式下不同链长脂肪酸与板栗淀粉（chestnut starch, CS）复合对板栗淀粉特性的影响。方法 通过测定淀粉及淀粉-脂质复合物的粒径大小,短程有序度、结晶度、糊化特性和流变特性,探究脂肪酸碳链长度和蒸煮方式对CS性质的影响。结果 脂肪酸的加入降低了CS颗粒尺寸、结晶度和短程有序性,增强了CS持水能力。同一蒸煮方式下,以板栗淀粉-月桂酸复合物变化最为明显,其次依次为板栗淀粉-肉豆蔻酸复合物、板栗淀粉-棕榈酸复合物。与常压蒸煮相比,高压蒸煮后淀粉持水能力增强,结晶结构更有序;短期老化淀粉的储能模量G''降低,损耗角正切值tan δ升高,表明抗短期老化性能提升。结论 不同碳链脂肪酸与CS 复合,短链脂肪酸及高压蒸煮复合效果更优,复合体系复合率更高,持水性能和抗短期回升效果更好。     

The role of amorphous phase content on the electrical properties of atmospheric plasma sprayed (Ba,Sr)TiO3 coatings

(Ba,Sr)TiO₃ coatings deposited on carbon steel substrates were successfully prepared by an atmospheric plasma spray system. Three sets of samples containing different amount of both crystalline and amorphous phases were deposited and consequently studied in order to determine their electrical properties. The results show a clear correlation existing between the amorphous phase content and coating´s electrical properties. The resistivity increases with increase of amorphous phase content. Relative permittivity for low frequencies decreases and become more stable with frequency tuning when amorphous phase content increased. The maximum relative permittivity value is in the range 75–200 for frequency 1 kHz. The loss factor varies between 0.23 and 0.03 for all studied samples. The loss factor is at the lower limit of these values and frequency much less dependent when the coating contains 15 wt% of amorphous phase and more. The band gap of all samples is between 2.75 eV and 2.90 eV. Microstructure and hardness were evaluated in order to determine basic mechanical properties of deposits.     

常减压装置塔顶管道腐蚀原因解析

针对目前原油品质日趋劣化,造成常减压装置塔顶管线腐蚀日益严重,经过腐蚀调查并分析腐蚀原因后,阐述了腐蚀的环境和机理,解决常减压蒸馏装置管线低温部位防腐的合理措施,提出了加强工艺调整PH值的控制,并合理的减缓腐蚀-加强对缓蚀剂和剂量控制,降低腐蚀所造成的风险。     

Application of sol gel spin coated yttria-stabilized zirconia layers for the improvement of solid oxide fuel cell electrolytes produced by atmospheric plasma spraying

Due to its high thermal stability and purely oxide ionic conductivity, yttria-stabilized zirconia (YSZ) is the most commonly used electrolyte material for solid oxide fuel cells (SOFCs). Standard electrolyte fabrication techniques for planar SOFCs involve wet ceramic techniques such as tape-casting or screen printing, requiring sintering steps at temperatures above 1300 °C. Plasma spraying (PS) may provide a more rapid and cost efficient method to produce SOFCs without sintering. High-temperature sintering requires long processing times and can lead to oxidation of metal alloys used as mechanical supports, or to detrimental interreactions between the electrolyte and adjacent electrode layers. This study investigates the use of spin coated sol gel derived YSZ precursor solutions to fill the pores present in plasma sprayed YSZ layers, and to enhance the surface area for reaction at the electrolyte-cathode interface, without the use of high-temperature firing steps. The effects of different plasma conditions and sol concentrations and solid loadings on the gas permeability and fuel cell performance have been investigated.     

Single-step process for transparent conductive ZnO:Ga films with uniform ultrahigh haze by oblique angle deposition

Increasing the haze of front electrodes of solar cells while retaining high optical transmittance is beneficial for increasing the power conversion efficiency. However, conventional methods of fabricating hazy films require additional etching steps or materials. Moreover, depositing large-area transparent conductive oxides with uniform ultrahigh haze is challenging. Here, we combine the oblique angle deposition and the atmospheric pressure plasma jet to produce GZO with a uniform ultrahigh haze of > 80% (non-uniformity ~1.35%), high transmittance of 88% (referenced to the substrate), and resistivity of 1.96 × 10^–3 Ω cm in a single step. We show that the high haze is caused by the “pre-deposition” of adsorbed particles on the bare substrate downstream and that the upstream dummy area should be avoided for high uniformity. Unlike existing methods, our method produces uniform films with ultrahigh haze and good transmittance in a single step without additional etching/ materials or changing parameters during operation.     

Investigation on dual corrosion performance of magnesium-rich primer for aluminum alloys under salt spray test (ASTM B117) and natural exposure

Magnesium-rich primers perform very well on outdoor exposure and actual test conditions, yet fail rapidly in accelerated corrosion testing (salt spray test - ASTM B117). To investigate the behavioral dichotomy, Mg-rich primers exposed to salt spray testing and natural weathering were characterized at periodic intervals. The results revealed the presence of a thin and porous magnesium hydroxide layer in primers exposed to salt spray, and in natural exposure, a thicker, protective magnesium carbonate layer was detected and characterized. Samples exposed to atmospheric carbon dioxide exhibit excellent corrosion resistance but salt spray conditions are not conducive to facilitate magnesium carbonate formation.     

Contribution of trace metals from atmospheric deposition to stormwater runoff in a small impervious urban catchment

The contribution of atmospheric deposition to emissions of trace metals in stormwater runoff was investigated by quantifying wet and dry deposition fluxes and stormwater discharges within a small, highly impervious urban catchment in Los Angeles. At the beginning of the dry season in spring 2003, dry deposition measurements of chromium, copper, lead, nickel, and zinc were made monthly for 1 year. Stormwater runoff and wet deposition samples also were collected, and loading estimates of total annual deposition (wet+dry) were compared with annual stormwater loads. Wet deposition contributed 1-10% of the total deposition inside the catchment, indicating the dominance of dry deposition in semi-arid regions such as Los Angeles. Based on the ratio of total deposition to stormwater, atmospheric deposition potentially accounted for as much as 57-100% of the total trace metal loads in stormwater within the study area. Despite potential bias attributable to processes that were not quantified in this study (e.g., resuspension out of the catchment or sequestration within the catchment), these results demonstrate atmospheric deposition represents an important source of trace metals in stormwater to waterbodies near urban centers.     

Changes in atmospheric corrosion rate caused by chloride ions depending on rain regime

Plain carbon steel and copper samples were exposed in two atmospheric test stations located in Havana, Cuba and Medellin, Colombia. Samples were submitted to accelerated outdoor test by intermittent spraying of a salt solution (SCAB test) according to ISO 11474:98.A remarkable difference in the acceleration rate of chloride ions for mild steel and copper between Cuban and Colombian stations was determined. Differences in rain amount and frequency between Havana and Medellin are noticeable. The influence of rain seems to be important in determining the acceleration rate of chloride ions on steel and copper due to its washing effect. A model for the influence of the interaction between rain characteristics and chloride deposition rate on mild steel and copper corrosion behaviour with time is proposed. Data fit very well to the proposed model. It is concluded that rain regime should be taken into account in order to determine the real acceleration rate caused by chloride ions in atmospheric conditions.     

环境因素对钢的大气腐蚀的影响

分析了我国七个试验点十七种钢的八年大气腐蚀试验结果,对润湿时间、二氧化硫及盐粒子的污染作用提出了新的看法。对非耐候钢,湿热条件对长期腐蚀的影响非常大,如果加上污染,会造成特别高的腐蚀。讨论了用气象及污染特征划分大气腐蚀性等级的ISO9223国际标准。碳钢、低合金钢在不同腐蚀环境中,暴露第一年期间所显示的大气腐蚀规律与长期暴露所显示的不同,因此用钢的第一年腐蚀结果来测定大气腐蚀性是不妥当的。