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排序方式: 共有1634条查询结果,搜索用时 15 毫秒
131.
Dhan Lord B. Fortela Rafael Hernandez Emmanuel Revellame William Holmes Wayne Sharp Mark Zappi 《Journal of the American Oil Chemists' Society》2019,96(9):1073-1079
This study focuses on new interpretations of the published literature by statistically evaluating the potential of microbial lipids from activated sludge (AS) as alternatives to high-value oils and fats. There are two data analysis stages involved in this study after compilation and organization of fatty acid profiles from the literature databases: (1) comparison of fatty acid profiles of the cultivated AS lipids with that of oils and fats found in the literature databases, and (2) hierarchical cluster analysis of the fatty acids of the combined dataset of literature oils and fats, and the AS lipids. Results show that fatty acid profiles of lipids from cultivated AS were similar to the fatty acid profiles of some oils and fats of plant, animal, single-microbial cultures, and algal origins; hence, lipids from AS could be potential alternatives to specialty oils and fats. The cultivation conditions of AS during lipid content enhancement may influence lipid application. 相似文献
132.
A branched polymer was prepared by grafting allyltrimethylammonium chloride onto polyvinyl alcohol (PVA) via free‐radical polymerization. Afterwards, a series of hybrid membranes were prepared by sol‐gel cross‐linking between quaternary ammonium‐PVA and tetraethoxysilane. The obtained membranes were characterized in terms of infrared spectroscopy, ion exchange capacity, water uptake, linear expansion ratio, and acid resistance. The thermal properties of the membranes were investigated as well. The diffusion dialysis performances of the membranes were tested by using a simulated feed solution containing HCl and FeCl2. The diffusion dialysis coefficients and the separation factors were much better than those of the commercial DF‐120 membrane. 相似文献
133.
Aline Guimont Emmanuel Beyou Pierre Alcouffe Philippe Cassagnau Anatoli Serghei Gregory Martin Philippe Sonntag 《Polymer》2014
Covalent functionalization of pentadecane-decorated thermally reduced graphite oxide (GO) sheets has been studied as a tool for the preparation of polyethylene/GO composites exhibiting rheological and electrical percolation thresholds. It was accomplished through pentadecane based radical addition onto unsaturated bonds located on the GO sheets' surface using dicumyl peroxide as hydrogen abstractor. This chemical functionalization influences the affinity of the formed pentadecane grafted GO sheets for various solvents. Then, the compounding of the composites pentadecane grafted GO/PE was performed at a processing temperature of 140 °C with 25, 20, 15, 10, 8 and 5 wt% loadings. Rheological and electrical percolation thresholds were found between 10 and 15 wt% for polyethylene/pentadecane functionalized graphene oxide composites while the composite graphite/PE at the same loading percentage did not reach any percolation threshold. 相似文献
134.
Jiahao Lv Hua Hao Xuewen Jiang Zhen Liu Marwa Emmanuel Minghe Cao Zhonghua Yao Hanxing Liu 《Journal of the American Ceramic Society》2020,103(9):5129-5138
Relaxor perovskite ferroelectric 0.1Bi(Zn1/2Zr1/2)O3-0.9BaTiO3(0.1BZZ-0.9BT) ceramics were successfully prepared, whose powders synthesized by the sol-gel process, with average grain size about 1.29 μm. 1.75 J/cm3 discharge energy density and good dielectric stability were obtained over a wide temperature range from 25°C to 140°C. The pulse discharge capability of 0.1BZZ-0.9BT ceramics was tested under different electric fields. The discharge time was 2.13 μs, which proved its ability to charge and discharge quickly. Complex impedance analysis and thermally stimulated depolarization current tests were applied to investigate the defect types and activation of 0.1BZZ-0.9BT ceramics. The evolution process of composite defects and oxygen vacancies profoundly affects the dielectric temperature stability of 0.1BZZ-0.9BT ceramics’ energy storage property. 相似文献
135.
Millicent Appiah Hua Hao Zheng Liu Shefiu Kareem Marwa Emmanuel Naomi Addai Asante Zhonghua Yao Minghe Cao Hanxing Liu 《Ceramics International》2021,47(17):24360-24371
In this study, the intermediate rare-earth oxide Gd2O3 (Gd) was substituted in different amounts (x = 0.2–2 mol%) for the formulation of BaTi1-xGdxO3-x/2 (BTGx) dielectric materials. The effect of B-site substitution was confirmed by the additional Raman active A1g octahedral peak at ~835cm-1 strengthened at x ≥ 0.4 mol%. Additionally, properties of 0.9BTG0.007-0.1BA dielectric ceramics were analysed based on the influence of various processing methods as a function of sintering temperature. The focal samples were labelled Method-A (direct-mix) and Method-B (indirect-mix). As the sintering temperature (1075–1200 °C) increased, the 1 kHz response of the ε–T curves of Method-A samples transformed from a single peak to broad-narrow double peaks of high dielectric loss tangent (tan δ). Nonetheless, samples of Method-B possessed a clearly defined transmission electron microscopy (TEM) core-shell structure, flattened double-peak ε-T curves, optimised dielectric properties (ε = ~1563–1851 and tan δ < 1.5% at room temperature), and a wide-ranging temperature behaviour that meets the X8R dielectric standards (ΔC/C25°C < ±15%). The maximum dielectric breakdown strength of Method-B samples reached ~131 kVcm, while the energy storage density was ~0.726 J/cm3 at a maximum efficiency of ~80% at 1100 °C. Thus, exhibiting good potentials for balancing temperature stability with energy storage applications. 相似文献
136.
The surface of two natural smectite-type clay samples was chemically modified by covalent grafting of amine groups, by reaction with γ-aminopropyltriethoxysilane, which were easily protonated in HCl medium. Multisweep cyclic voltammograms of clay-film modified glassy carbon electrodes made of either the raw clays or the propylammonium-functionalized samples exposed to Ru(NH3)63+ or Fe(CN)63− electroactive probes were obtained. The results indicated a permselective behavior of these clay and organoclay-films based on either favorable or unfavorable electrostatic interactions. The cation-exchanging raw clay film modified electrodes exhibited accumulation properties for Ru(NH3)63+ species while rejecting Fe(CN)63−, whereas the anion-exchanging organoclay coatings acted as a barrier against Ru(NH3)63+ while increasing dramatically the concentration of Fe(CN)63− species at the electrode surface. Strong binding of the probe to the organoclays resulted in a potential shift of ca. 0.1 V of the voltammetric signals characteristic of the Fe(CN)63−/4− couple in the anodic direction. Their good preconcentration efficiency at low analyte concentration highlighted their interest for electroanalytical applications. 相似文献
137.
The simplicity principle—an updating of Ockham's razor to take into account modern information theory—states that the preferred theory for a set of data is the one that allows for the most efficient encoding of the data. We consider this in the context of classification, or clustering, as a data reduction technique that helps describe a set of objects by dividing the objects into groups. The simplicity model we present favors clusters such that the similarity of the items in the clusters is maximal, while the similarity of items between clusters is minimal. Several novel features of our clustering criterion make it especially appropriate for clustering of data derived from, psychological procedures (e.g., similarity ratings): It is non-parametric, and may be applied in situations where the metric axioms are violated without requiring (information-forgetting) transformation procedures. We illustrate the use of the criterion with a selection of data sets. A distinctive aspect of this research is that it motivates a clustering algorithm from psychological principles. 相似文献
138.
This paper considers the design of robust l1 estimators based on multiplier theory (which is intimately related to mixed structured singular value theory) and the application of robust l1 estimators to robust fault detection. The key to estimator-based, robust fault detection is to generate residuals which are robust against plant uncertainties and external disturbance inputs, which in turn requires the design of robust estimators. Specifically, the Popov-Tsypkin multiplier is used to develop an upper bound on an l1 cost function over an uncertainty set. The robust l1 estimation problem is formulated as a parameter optimization problem in which the upper bound is minimized subject to a Riccati equation constraint. A continuation algorithm that uses quasi-Newton BFGS (the algorithm of Broyden, Fletcher, Goldfab and Shanno) corrections is developed to solve the minimization problem. The estimation algorithm has two stages. The first stage solves a mixed-norm H2/l1 estimation problem. In particular, it is initialized with a steady-state Kalman filter and, by varying a design parameter from 0 to 1, the Kalman filter is deformed to an l1 estimator. In the second stage the l1 estimator is made robust. The robust l1 estimation framework is then applied to the robust fault detection of dynamic systems. The results are applied to a simplified longitudinal flight control system. It is shown that the robust fault detection procedure based on the robust l1 estimation methodology proposed in this paper can reduce false alarm rates. 相似文献
139.
A digital rights management scheme for broadcast video 总被引:2,自引:0,他引:2
Many watermarking techniques have been proposed for digital video and digital broadcast video. In general, they address the
seller's or broadcaster's concerns, such as copyright-violation deterrence, copyright-violation detection and copy protection.
Some of them provide for data integrity (tamper proofing), which is a shared concern of both subscriber and broadcaster. In
all these cases, the watermark generation and embedding is performed or controlled by the seller or broadcaster. Therefore,
a broadcaster with malicious intentions could, with manipulation, falsely implicate an innocent subscriber in copyright violation.
This could be a major concern for subscribers.
In this paper, we propose an integrated solution to manage the broadcaster's copyright and subscriber's false-implication
concern (subscriber's rights) for digital video broadcasts. The proposed novel approach makes use of interactive watermarking
techniques and protocols to help protect digital rights of all parties involved in video broadcasting. 相似文献
140.
Emmanuel Benoist Jean-Jacques Hébrard 《Annals of Mathematics and Artificial Intelligence》2003,37(3):251-272
The enlarged Horn formulas generalize the extended Horn formulas introduced by Chandru and Hooker (1991). Their satisfying truth assignments can be generated with polynomial delay. Unfortunately no polynomial algorithm is known for recognizing enlarged Horn formulas or extended Horn formulas. In this paper we define the class of simple enlarged Horn formulas, a subclass of the enlarged Horn formulas, that contains the simple extended Horn formulas introduced by Swaminathan and Wagner (1995). We present recognition algorithms for the simple enlarged Horn formulas and the simple extended Horn formulas whose complexity is bounded by the complexity of the arborescence-realization problem. 相似文献