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排序方式: 共有165条查询结果,搜索用时 15 毫秒
1.
Multimedia Tools and Applications - In this paper, blind image quality assessment (IQA) of Gaussian blurred images based on Discrete Fourier Transform (DFT) is proposed. The proposed work is based...  相似文献   
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Nanoscale electrocatalytic materials having enhanced electroactive sites has been considered trendier and can drive kinetically uphill OER at much lower energy cost with high efficiency. However, very complex synthetic strategies, extensive functionalization processes, and less stability have stimulated quest for economically viable, straightforward and facile preparative methods for designing stable, robust and active nanoscale electrocatalysts engaging geologically abundant materials to ensure their industrial implications. Here we present surface-assembled Fe(OH)x/FeOx type colloidal catalytic thin-films, with or without post annealing, derived from Fe-colloidal NPs in simple carbonate system for efficient water oxidation. Comprehensive electrochemical studies including cyclic voltammetry, chronoamperometry, chronopotentiometry, impedance spectroscopy, Tafel slope analysis, mass activity, electrochemically active surface area measurements are conducted to comparatively evaluate the performance of simple (FeOx/HCO3?@FTO and annealed (FeOx/HCO3?@FTO250, FeOx/HCO3?@FTO500) catalysts for oxygen evolution reaction (OER) under employed conditions. The FeOx/HCO3?@FTO250 annealed at 250 °C initiates water oxidation at much lower overpotential of 1.52 V vs. RHE with remarkable stability during long-term electrochemical experimentations. In addition to enhanced OER activity as evidence by better onset potential (<1.55 V vs. RHE), lower Tafel slope value (36 mV dec1?) and negligible charge transfer resistance, the Fe(OH)x/HCO3?@FTO type catalyst presented excellent electroactive nature during long term controlled potential electrolysis experiments where more and more electroactive sites were getting exposed during continuous hours of electrolysis. The catalysts behave as a potential enduring, inexpensive and competent candidate for catalyzing water oxidation reaction when tested under begin conditions.  相似文献   
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More than 70 % of women with ovarian cancer are diagnosed with advanced-stage disease, which is initially treated with cytoreductive surgery, and combination chemotherapy with platinum-based compounds. Most patients initially respond to platinum-based therapy, but eventually up to 80 % of this responsive cohort becomes refractory due to the development of platinum resistance. This review discusses current and potential therapeutic approaches that exploit biomaterial-based applications to combat platinum resistance either by enhancing the delivery of platinum-based drugs or prodrugs, delivering other toxic non-platinum-based bioactive factors (by themselves or in combination with platinum-based drugs) or by delivering other bioactive factors that re-sensitize resistant ovarian cancer cells to these drugs. The types of materials that are used, the bioactive factors applied (i.e., drug or gene delivery), and the specific agents that are employed to target these types of cancer cells are discussed. We conclude that the unique attributes of biomaterial-based applications can be further explored toward overcoming platinum-resistant ovarian cancer as monotherapy, or in combination with other treatment strategies.  相似文献   
5.
The rapid growth of vehicular pollution; mostly running on the diesel engine, emissions emerging are the concerns of the day. Owing to clean burn characteristics features, Hydrogen (H2) as a fuel is the paradigm of the researcher. Extensive research presented in the literature on H2 dual fueled diesel engine reveals, the significant role of H2 in reducing emissions and enhancing the performance of a dual fueled diesel engine. With meager qualitative experiment data, the feasibility to develop an efficient Artificial Neural Network (ANN) model is investigated, the developed model can be utilized as a tool to investigate the H2 dual fueled diesel engine further. In the process of developing an ANN model, engine load and H2 flow rate are varied to register performance and emission characteristics. The creditability of the experiment is ascertained with uncertainty analysis of measurable and computed parameters. Leave-out-one method is adopted with 16 data sets; seven training algorithms are explored with eight transfer function combinations to evolve a competent ANN model. The efficacy of the developed model is adjudged with standard benchmark statistic indices. ANN model trained with Broyden, Fletcher, Goldfarb, & Shanno (BFGS) quasi-Newton backpropagation (trainbfg) stand out the best among other algorithms with regression coefficient ranging between 0.9869 and 0.9996.  相似文献   
6.
Keystream reuse, also known as the two time pad problem, is a well known weakness in stream ciphers. The implementers of the cryptographic algorithms are still underestimating this threat. The keystream reuse exploitation techniques presented so far assume the underlying plaintext to be textual data and all the heuristics presented previously are based on the language characteristics of the underlying text based data, which fail when compression is applied on the plaintext before encryption. This paper presents exploitation techniques for two time pads in case of stream ciphered digitized and compressed speech signals. In this paper we show that how an adversary can automatically recover the digitized speech signals encrypted under the same keystream provided the language (e.g. English) and digital encoding/compression scheme details of the underlying speech signals are known. Our technique of cryptanalysis is based on the modeling of the speech parameters by exploiting the inter frame correlations between each components of the speech vectors in different frames and then using these models to decode the two speech signals in the keystream reuse scenario. The technique is flexible enough to incorporate all modern speech coding schemes based on parameter or hybrid encoding and compression techniques. The simulation experiments have showed promising results for most of the present day speech digitization and compression techniques.  相似文献   
7.
In present work, the concentrations of toxic elements, aluminium (Al), cadmium (Cd), nickel (Ni) and lead (Pb) were measured in different solid baby foods (BFs), primarily to evaluate whether the intakes comply within permissible levels of these toxic elements (TEs). The BFs were evaluated for total contents of TEs, using a simple and fast ultrasound-assisted extraction (UAE) method. The accuracy of the proposed UAE method was ensured by using certified reference materials and results obtained by conventional wet acid digestion method on same CRM, at 95% confidence level. The range of the investigated TEs in different BFs were 4770–35,200, 25.6–88.3, 124–332 and 52.5–90.6 μg/kg for Al, Cd, Ni and Pb, respectively. The results indicated that BFs including rice cereals have high level of all four TEs. The daily intakes of TEs for children through BFs have also been estimated, and are well below the recommended tolerable levels.  相似文献   
8.
On-package graphics have the potential to influence consumers’ product-related attitudes and behaviours. In the reported study graphics designs on the labels of two products (water and vodka) were manipulated with respect to shape angularity, orientation, and left–right alignment. Participants’ evaluations indicated a preference for rounded shapes that could not be accounted for by differences in design typicality; and preference for upward shape orientation. An interaction between these response variables for ratings of purchase likelihood suggested that congruence between graphical and product form (droplet shape) may be advantageous. Effects of alignment were not consistent with existing theories, with right-aligned graphics being preferred. An explanation that distinguishes processing efficiency and hemispheric efficiency is proposed. Finally, as predicted, a halo effect was apparent, such that effects of aesthetic manipulations extended to ratings of product attributes that were not experienced. Theoretical and practical implications of these results are discussed.  相似文献   
9.
Due to an increase in the commercial use of biodiesel and biodiesel blends, both ASTM D 6751 and EN 14214 include the acid number (AN) as an important quality parameter. It was found that determination of AN of biodiesel and biodiesel blends using the ASTM D 974 results in large values of repeatability (up to 73.41%) and larger percentage error (up to 42.88%). Therefore, ASTM D 974 has been modified using a lower concentration of base (0.02 M KOH instead of 0.1 M KOH) as well as reducing the amount of toxic titration solvent from 100 mL to only 10 mL. This makes the modified ASTM D 974 as a green analytical method which uses a reduced amount of toxic solvent. This modified method significantly reduced the maximum percentage error from 42.88 to 5.92%. The application of this modified ASTM D 974 for the determination of AN of biodiesel and biodiesel blends was studied. The accuracy of this modified ASTM D 974 for biodiesel (B100) was measured to be within 3.51% over the AN range of 0.313–0.525 mg KOH/g and maximum repeatability was decreased from 8.37 to 2.75% within this AN range which is far below the ASTM D 974 stated repeatability specifications. For B20, B10, B5, B2, and B1, the most accurate values were measured at AN values of 0.177, 0.067, 0.072, 0.126, and 0.096 mg KOH/g, respectively. Excellent linearity values of R 2 for calculated and experimentally determined AN were obtained. The difference between the experimental and the calculated AN for all biodiesel and biodiesel blend samples was within ± 0.018 mg KOH/g. This extensive study has demonstrated that this modified ASTM D 974 is a reliable method for the determination of AN and could be used for establishing the specifications of AN for biodiesel and biodiesel blends ranging from B1 to B20 in quality standards.  相似文献   
10.
After a gap of more than two decades, Concentrator Photovoltaics (CPV) technology is once again under spotlight for making use of the best available solar cell technologies and improving the overall performance. CPV finds its use in a number of applications ranging from building integration to huge power generation units. Although the principles of solar concentration are well understood, many practical design, operation, control issues require further understanding and research. A particular issue for CPV technology is the non-uniformity of the incident flux which tends to cause hot spots, current mismatch and reduce the overall efficiency of the system. Understanding of this effect requires further research, and shall help to employ the most successful means of using solar concentrators. This study reviews the causes and effects of the non-uniformity in the CPV systems. It highlights the importance of this issue in solar cell design and reviews the methods for the solar cell characterization under non-uniform flux conditions. Finally, it puts forward a few methods of improving the CPV performance by reducing the non-uniformity effect on the concentrator solar cells.  相似文献   
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