A facial approach to fabricate superhydrophobic aluminum surface

A facial chemical etching method was developed for fabricating superhydrophobic aluminum surfaces. The resultant surfaces were characterized by scanning electron microscopy, water contact angle (WCA) measurement, and optical methods. The surfaces of the modified aluminum substrates exhibit superhydrophobicity, with a WCA of 154.8° ± 1.6° and a water sliding angle of about 5°. The etched surfaces have binary structure consisting of the irregular microscale plateaus and caves in which there are the nanoscale block‐like convexes and hollows. The superhydrophobicity of aluminum substrates occurs only in some structures in which the plateaus and caves are appropriately ordered. The resulted surfaces have good self‐cleaning properties. The results demonstrate that it is possible to construct superhydrophobic surface on hydrophilic substrates by tailoring the surface structure to providing more spaces to trap air. Copyright © 2009 John Wiley & Sons, Ltd.     

Mn(OH)_2空气氧化反应实验与产物表征

锰属于ⅦＢ族元素 ,其价电子构型为 3ｄ54ｓ2 ,具有ｄ区元素多种氧化态的特征 ,它的氧化态表现有 + 2、+ 3、+ 4、+ 6、+ 7,锰系化合物的化学性质也是多种多样的。关于Ｍｎ(Ⅱ )的还原性已多见报道[1～ 3 ] ,在酸性介质中Ｍｎ2 + 比较稳定 ,需要强氧化剂才能将其氧化 ,而在碱性介质中Ｍｎ2 + 沉淀为Ｍｎ(ＯＨ)2 ,易被氧化 ,即使与空气接触也能被氧化成棕色的ＭｎＯ(ＯＨ)2 。2Ｍｎ(ＯＨ) 2 +Ｏ2 =2ＭｎＯ(ＯＨ) 2 ( 1 )作出上述结论的依据是Ｍｎ的标准电极电势图[3 ] :由标准电极电势图可见 ,在碱性条件下Ｏ2 有将Ｍｎ(ＯＨ) 2 氧化成ＭｎＯ…     

Beam profile measurement with CR-39 track detector for low-energy ions

A CR-39 track detector was successfully used to measure the outline of thin low-energy ion beams. After the etching, the surface of the detector was examined with an observation system composed of a Normarski microscope, a CCD camera and a digital image processing computer. Beam images obtained with the system were in good agreement on the outline of the beam formed with a beam aperture. Also, the resolving power in the beam outline measurement was roughly explained from the consideration of the ion range and the etch-pit growth in the chemical etching for the CR-39 detector.     

On the response of LR-115 plastic track detector to 10 20 Ne-ion

The track etch rates of ₁₀ ²⁰ Ne-ion in cellulose nitrate (LR-115) have been measured for different temperatures and the activation energy is determined. The experimental results show that both the track etch rate and the normalized track etch rate depend on the energy loss as well as on etching temperature. The maximum etched track length of ₁₀ ²⁰ Ne-ion agrees with the theoretically computed range. The experimental results show that there is no sharp threshold, at least in CN(LR-115).     

Radon activity and exhalation rates measurements in fly ash from a thermal power plant

Radon exhalation rate from fly ash samples and from the homogeneous mixture of fly ash of different proportions additive in soil and cement samples to study the effect of the addition was measured by cup dosimeter using SSNTDs. Radon activities were found to vary from (1018±38) to ( whereas the radon exhalation rate varied from (366±14) to . A gradual increase has been observed in samples having fly ash as an additive in cement samples whereas a gradual decrease was observed in soil samples after the addition of fly ash. ²³⁸U in fly ash was measured by a low-level NaI (Tl)-based gamma ray spectrometer. The results show enhancement in U concentration in fly ash as compared to coal samples, whereas radon exhalation rate is less in fly ash samples.     

CO2 dial for monitoring atmospheric pollutants at the University of Calabria

Summary In this report we introduce the infrared lidar-dial apparatus developed at the University of Calabria. It has been carried out as a tool in the investigation of both the atmospheric pollution of trace gases and other atmospheric parameters as water vapour. The general scheme of the station is described, as well as the performances of the home-made CO₂ laser sources. Finally preliminary measurements of average concentration of ozone and water vapour over a range of about 3 km are presented and discussed in the report.     

山背波:对飞机的潜在威胁

山背波对飞机的潜在威胁现已毋庸置疑。为了提高在这方面作出更确切判断的能力并能进一步找出实践中可行的相应措施，首要的问题就是必须对山背波本身有足够的认识，而这正是当前国内文献中极为薄弱的环节。有鉴于此，本文系统地、较全面地介绍了山背波这种独特的次声波，对其发生机理和基本特征、以及作为其直接衍生物的相关云相和晴空湍流－－后者正是对飞机的主要潜在威胁所在－－作出简明扼要的评述。     

Determination of triethanolamine in air samples by gas chromatography-mass spectrometry

Summary Low amounts of triethanolamine, collected in ORBO 53 tubes during air sampling, required the development of a very sensitive method for determination. After desorption and silylation reaction with trimethylsilyl imidazole/trimethyl chlorosilane, the derivative was analyzed by gas chromatography-mass spectrometry on an Ultra 2 silica capillary column in single ion monitoring mode (retention time: about 6 min). The method has a detection limit of 1–2 pg with a desorption efficiency of about 81%. Linearity of response was ascertained in the ranges 10–100 ng and 100–1000 ng. Short-term method validation was carried out by intra- and inter-day assays on three amounts for each reference calibration curve. All results satisfied the pre-defined acceptance criteria. In general, the whole procedure was easily performed and was appropriate for our needs. Breakthrough volume was appropriate for our needs. Breakthrough volume was determined on authentic samples and was about 40–60 L, using a flow rate of 1 L·min⁻¹. The amounts of triethanolamine found in the samples ranged from 150 to 250 ng (about 2.5–4.2 μg·m⁻³).     

Comparison of responses of LR-115A, CR-39 and PM-355 track detectors to pulsed low-energy proton streams

The paper concerns applications of LR-115A, CR-39 and PM-355 solid-state nuclear-track detectors (SSNTDs) for investigation of pulsed fluxes of protons below 300 keV. The proton streams were generated by the RPI-IBIS device operated with hydrogen puffing [Baranowski et al. 2000. Studies of hydrogen discharges in RPI-type devices with different electrode configurations. Czech. J. Phys. 50 (Suppl. S3), 101–107]. To perform ion mass- and energy-analysis, a Thomson mass-spectrometer equipped with a special input system and exchangeable detectors was used. A quantitative analysis of proton tracks upon Thomson parabolas was performed by means of an optical microscope equipped with a CCD camera. It made possible to measure proton tracks and to determine their statistics. The paper presents proton energy spectra recorded with the selected detectors, and responses of these detectors to protons of energy from about 30 to 300 keV. The results are important for verification of detector characteristics and for measurements of protons at different experimental conditions.     

The use of apatite fission track thermochronology to constrain fault movements and sedimentary basin evolution in northeastern Brazil

An apatite fission track study of crystalline rocks underlying sedimentary basins in northeastern Brazil indicate that crustal blocks that occur on opposite sides of a geological fault experienced different thermal histories. Samples collected on the West block yielded corrected fission-track ages from 140 to 375 Ma, whereas samples collected on the East block yielded ages between 90 and 125 Ma. The thermal models suggest that each block experienced two cooling events separated by a heating event at different times. We concluded that the West block moved downward relative to the East block ca. 140 Ma ago, when sediments eroded from the East side were deposited on the West side. This process represents the early stage of sedimentary basin formation and the opening of the South Atlantic Ocean in the region. Downward and upward movements related to heating and cooling events of these crustal blocks at different periods until recent times are proposed.