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排序方式: 共有100条查询结果,搜索用时 15 毫秒
1.
Kee S. Moon M. Levy Yong K. Hong H. Bakhru S. Bakhru 《Ferroelectrics Letters Section》2003,30(3):47-57
Advances in the fabrication of solid-solution single crystal relaxor ferroelectrics have made it possible to produce highly efficient piezoelectric crystals, and have attracted renewed interest in the use of these crystals for a new generation of piezoelectric transducers, actuators and sensors. Of particular interest is their incorporation into micro-electromechanical systems (MEMS). In this paper we report on the laser-induced wet chemical etching of lead zinc niobate-lead titanate (PZN-PT) in hydrochloric acid (HCl). Argon-ion laser radiation at power levels up to 4 W is focused to a spot diameter of about 15μm and results in the chemical etching of grooves at patterning speeds up to 5μm/sec. Crystal ion slicing, an ion-implant-based film separation technique, is used in combination with laser etching to form 5 to 10μm-thick patterned and freestanding films for incorporation into micro-electromechanical devices. 相似文献
2.
3.
Patrick J. Gray Sean D. Conklin Todor I. Todorov Sasha M. Kasko 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2016,33(1):78-85
This paper reports the effects of rinsing rice and cooking it in variable amounts of water on total arsenic, inorganic arsenic, iron, cadmium, manganese, folate, thiamin and niacin in the cooked grain. We prepared multiple rice varietals both rinsed and unrinsed and with varying amounts of cooking water. Rinsing rice before cooking has a minimal effect on the arsenic (As) content of the cooked grain, but washes enriched iron, folate, thiamin and niacin from polished and parboiled rice. Cooking rice in excess water efficiently reduces the amount of As in the cooked grain. Excess water cooking reduces average inorganic As by 40% from long grain polished, 60% from parboiled and 50% from brown rice. Iron, folate, niacin and thiamin are reduced by 50–70% for enriched polished and parboiled rice, but significantly less so for brown rice, which is not enriched. 相似文献
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5.
One of the most fascinating properties of materials in nature is the superhydrophobic and self‐cleaning capabilities of different plant surfaces. This is usually achieved by the hydrophobic cuticles that are made of cutin and contain wax crystals both within them and on their surfaces. Here, bioinspired n‐hexatriacontane wax films are deposited via thermal evaporation and it is shown that the surface evolves in time via self‐assembly. This leads to a dramatic change in the wetting properties with a transition from hydrophobic to superhydrophobic characteristics, which takes place within several days at room temperature. This phenomenon is investigated and strain‐induced recrystallization is proposed to be the mechanism for it. This work could become the basis for the inspiration and production of tuned, time‐dependant, temperature‐sensitive, variable‐wettability surfaces. 相似文献
6.
Synthesis of graphene-based nanosheets via chemical reduction of exfoliated graphite oxide 总被引:27,自引:0,他引:27
Sasha Stankovich Richard D. Piner Alfred Kleinhammes Yue Wu Rodney S. Ruoff 《Carbon》2007,45(7):1558-1565
Reduction of a colloidal suspension of exfoliated graphene oxide sheets in water with hydrazine hydrate results in their aggregation and subsequent formation of a high-surface-area carbon material which consists of thin graphene-based sheets. The reduced material was characterized by elemental analysis, thermo-gravimetric analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, NMR spectroscopy, Raman spectroscopy, and by electrical conductivity measurements. 相似文献
7.
Heat transfer is observed as a function of temperature on small horizontal wires in water and four organic liquids. When the wire radius is sufficiently small, the hydrodynamic transitions in the boiling curve disappear and the curve becomes monotonie. Three modes of heat removal are identified for the monotonie curve and described analytically: a natural convection mode, a mixed film boiling and natural convection mode, and a pure film boiling mode. Nucleate boiling does not occur on the small wires. 相似文献
8.
Kinetic and mechanistic evaluation of tetrahydroborate ion electro-oxidation at polycrystalline gold
The anodic oxidation of tetrahydroborate ion is studied in NaOH at stationary and rotating polycrystalline Au disk electrodes. Linear sweep and cyclic voltammetry are applied varying the scan and rotation rate from 0.005 to 51.200 V s−1 and from 52.3 to 314.1 rad s−1, correspondingly. The effects of variation of BH4− and NaOH concentrations as well as of the potential limits of the ranges studied have been initially followed. Most of the experiments have been carried out with 10.9 mM NaBH4 in 1.04 M NaOH at 293 K in the potential range from −1.300 to 0.900 V (vs. Ag/AgCl). It is found that 6 electrons are exchanged in the overall oxidation transformation. The kinetic analysis of the processes determining the two anodic peaks recorded under static conditions at scan rates lower than 0.500 V s−1 shows that 1.4 electrons are exchanged in the potential range of the first one (at ca −0.5 V), while the rate of the second one (at ca +0.3 V) is determined by a quasi-reversible 1-electron transfer reaction. A kinetic evidence for the participation of surface bound intermediates in the electro-oxidation process is provided. Two additional well outlined anodic peaks are recorded in the aforementioned potential range under specific experimental conditions. A quasi-8 electron mechanism involving four oxidation and hydrolysis steps is advanced to explain the experimental results. It accounts for the involvement of borohydride oxidation species and the Au+/Au3+ mediator couple. 相似文献
9.
Sasha Ivkovic John Yearwood Andrew Stranieri 《Information & Communications Technology Law》2002,11(1):35-47
The Knowledge Discovery from Databases (KDD) technique called 'association rules' is applied to a large data set representing applicants for government-funded legal aid. Results indicate that KDD can be an invaluable tool for legal analysts. Association rules discovered identify associations between variables that are present in the data set though are not necessarily causal. Interesting rules can prompt analysts to formulate hypotheses for further investigation. The identification of interesting rules is typically performed using an objective measure of 'interesting' although this measure is often not sufficiently accurate to eliminate all uninteresting rules. In this article, a subjective measure of interestingness is adopted in conjunction with the objective measures. This leads to the ability to focus more accurately on those rules that surprise the analyst and are therefore more likely to be interesting. In general, KDD techniques have not been applied to law despite possible benefits because data is often stored in narrative form rather than in structured databases. However, the impending introduction of data warehouses that collect data from a number of organizations across a legal system presents invaluable opportunities for analysts using KDD. 相似文献
10.
Modeling of ammonia speciation in anaerobic digesters 总被引:2,自引:0,他引:2
Anaerobic digestion of high-nitrogen wastes such as animal manure can be inhibited by high concentrations of un-ionized ammonia, NH3 (aq). Understanding the toxicity of NH3 (aq) to anaerobic digestion requires a method for determining its concentration. Previous work on ammonia toxicity in anaerobic digesters has utilized a simple equilibrium calculation for estimating NH3 (aq) concentration from total ammonia, temperature, and pH. This approach is not appropriate for concentrated solutions. In this work, a speciation model for major solutes in anaerobic digesters, based on Pitzer's ion-interaction approach, is presented. Model simulations show that the simple equilibrium calculation (without corrections for non-ideal behavior) substantially overestimates NH3 (aq) concentration for all but dilute digesters. This error in concentration determination increases with total solids content and is estimated to be greater than 40% for a digester fed dairy manure with 5% total solids or swine manure with 3% total solids. However, including an estimate of the activity coefficient for NH4+ in the simple equilibrium calculation results in much more accurate estimates of NH3 (aq) concentration. In this case, the estimated error is less than 10% in the absence of struvite precipitation at the highest total solids contents considered. 相似文献