850 resultados para Effective notch stress method
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An effective and facile method for fabrication of large area of aggregated gold nanorods (AuNRs) film was proposed by self-assembly of AuNRs at a toluene/water interface for the first time. It was found that large area of aggregated AuNRs film could be formed at the interface of toluene and water due to the interfacial tension between the two phases. The obtained large area of aggregated AuNRs film exhibits strong surface-enhanced Raman scattering (SERS) activity with 4-aminothiophenol (4-ATP) and 2-aminothiophenol (2-ATP) as the probe molecules based on the strong electromagnetic coupling effect between the very adjacent AuNRs.
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Four saponins were isolated from the leaves of Aralia elata, and established using NMR and other spectroscopic methods, as well as data reported in the literature. Three Aralia saponins from the leaves of Aralia elata sharing the same structures as those isolated from the root bark suggested that the leaves would be a good substitute for the root bark of Aralia elata. These four Aralia saponins were then extensively investigated using complementarily positive and negative electrospray ionization multistage tandem mass spectrometry (ESI-MSn). Two isomers of saponins with different sugar linkages were then successfully differentiated by positive ESI-MSn and verified with different retention times and the collision-induced dissociation (CID) spectra by LC-MS. A simple and effective LC-MS method was thus developed for the rapid identification and screening of these saponins in plant extracts from leaves of Aralia elata.
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Gas bubble dynamic template, a new green and promising template, can be used to prepare nanostructured materials with different shapes from electrochemical deposition processes. Different morphological platinum nanomaterials have been synthesized by the replacement reaction of the deposited copper nanomaterials which were obtained under negative potential along with H-2 evolution (dynamic template) at a glassy carbon electrode. Scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and electrochemical methods were adopted to characterize their structures and properties. The nanomaterials platinum exhibited excellent catalytic activity toward oxygen reduction. The results demonstrated that the strategy is a simple, cost-effective, and potent method to prepare platinum nanomaterials.
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进行一个多装配机器人系统 DAMAS的模型研究 ,介绍离散事件动态系统的重要建模工具 Petri网 ,提出解决模型复杂性的有效方法 ,建立了系统中各个 Agent及整个系统的 Petri网模型 ,对这些模型及相互间的交互模型进行了重要的活性和有界性分析 ,对多机器人系统的协作机制进行了验证分析。
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本文提出了机器人末端过空间三点作空间圆弧运动的一种有效轨迹规划方法,并成功地应用于我们开发的电子装配机器人中.理论分析与实验分析的结果一致
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The seismic survey is the most effective prospecting geophysical method during exploration and development of oil/gas. The structure and the lithology of the geological body become increasingly complex now. So it must assure that the seismic section own upper resolution if we need accurately describe the targets. High signal/noise ratio is the precondition of high-resolution. For the sake of improving signal/noise ratio, we put forward four methods for eliminating random noise on the basis of detailed analysis of the technique for noise elimination using prediction filtering in f-x-y domain. The four methods are put forward for settling different problems, which are in the technique for noise elimination using prediction filtering in f-x-y domain. For weak noise and large filters, the response of the noise to the filter is little. For strong noise and short filters, the response of the noise to the filter is important. For the response of the noise, the predicting operators are inaccurate. The inaccurate operators result in incorrect results. So we put forward the method using prediction filtering by inversion in f-x-y domain. The method makes the assumption that the seismic signal comprises predictable proportion and unpredictable proportion. The transcendental information about predicting operator is introduced in the function. The method eliminates the response of the noise to filtering operator, and assures that the filtering operators are accurate. The filtering results are effectively improved by the method. When the dip of the stratum is very complex, we generally divide the data into rectangular patches in order to obtain the predicting operators using prediction filtering in f-x-y domain. These patches usually need to have significant overlap in order to get a good result. The overlap causes that the data is repeatedly used. It effectively increases the size of the data. The computational cost increases with the size of the data. The computational efficiency is depressed. The predicting operators, which are obtained by general prediction filtering in f-x-y domain, can not describe the change of the dip when the dip of the stratum is very complex. It causes that the filtering results are aliased. And each patch is an independent problem. In order to settle these problems, we put forward the method for eliminating noise using space varying prediction filtering in f-x-y domain. The predicting operators accordingly change with space varying in this method. Therefore it eliminates the false event in the result. The transcendental information about predicting operator is introduced into the function. To obtain the predicting operators of each patch is no longer independent problem, but related problem. Thus it avoids that the data is repeatedly used, and improves computational efficiency. The random noise that is eliminated by prediction filtering in f-x-y domain is Gaussian noise. The general method can't effectively eliminate non-Gaussian noise. The prediction filtering method using lp norm (especially p=l) can effectively eliminate non-Gaussian noise in f-x-y domain. The method is described in this paper. Considering the dip of stratum can be accurately obtained, we put forward the method for eliminating noise using prediction filtering under the restriction of the dip in f-x-y domain. The method can effectively increase computational efficiency and improve the result. Through calculating in the theoretic model and applying it to the field data, it is proved that the four methods in this paper can effectively solve these different problems in the general method. Their practicability is very better. And the effect is very obvious.
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The seismic survey is the most effective prospecting geophysical method during exploration and development of oil/gas. The structure and the lithology of the geological body become increasingly complex now. So it must assure that the seismic section own upper resolution if we need accurately describe the targets. High signal/noise ratio is the precondition of high-resolution. As one important seismic data processing method, Stacking is an effective means to suppress the records noise. Broadening area of surface stacked is more important to enhance genuine reflection signals and suppressing unwanted energy in the form of coherent and random ambient noise. Common reflection surface stack is a macro-model independent seismic imaging method. Based on the similarity of CRP trace gathers in one coherent zone, CRS stack effectively improves S/N ratio by using more CMP trace gathers to stack. It is regarded as one important method of seismic data processing. Performing CRS stack depends on three attributes. However, the equation of CRS is invalid under condition of great offset. In this thesis, one method based on velocity model in depth domain is put forward. Ray tracing is used to determine the traveltime of CRP in one common reflection surface by the least squares method to regress the equation of CRS. Then we stack in the coherent seismic data set according to the traveltime, and get the zero offset section. In the end of flowchart of implementing CRS stack, one method using the dip angle to enhance the ratio of S/N is used. Application of the method on synthetic examples and field seismic records, the results of this method show an excellent performance of the algorithm both in accuracy and efficiency.
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R. Jensen and Q. Shen, 'Fuzzy-Rough Data Reduction with Ant Colony Optimization,' Fuzzy Sets and Systems, vol. 149, no. 1, pp. 5-20, 2005.
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Gemstone Team Cogeneration Technology
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Particle degradation can be a significant issue in particulate solids handling and processing, particularly in pneumatic conveying systems, in which high-speed impact is usually the main contributory factor leading to changes in particle size distribution (comparing the material to its virgin state). However, other factors may strongly influence particles breakage as well, such as particle concentrations, bend geometry,and hardness of pipe material. Because of such complex influences, it is often very difficult to predict particle degradation accurately and rapidly for industrial processes. In this article, a general method for evaluating particle degradation due to high-speed impacts is described, in which the breakage properties of particles are quantified using what are known as "breakage matrices". Rather than a pilot-size test facility, a bench-scale degradation tester has been used. Some advantages of using the bench-scale tester are briefly explored. Experimental determination of adipic acid has been carried out for a range of impact velocities in four particle size categories. Subsequently, particle breakage matrices of adipic acid have been established for these impact velocities. The experimental results show that the "breakage matrices" of particles is an effective and easy method for evaluation of particle degradation due to high-speed impacts. The possibility of the "breakage matrices" approach being applied to a pneumatic conveying system is also explored by a simulation example.
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The standard local density approximation and generalized gradient approximations fail to properly describe the dissociation of an electron pair bond, yielding large errors (on the order of 50 kcal/mol) at long bond distances. To remedy this failure, a self-consistent Kohn-Sham (KS) method is proposed with the exchange-correlation (xc) energy and potential depending on both occupied and virtual KS orbitals. The xc energy functional of Buijse and Baerends [Mol. Phys. 100, 401 (2002); Phys. Rev. Lett. 87, 133004 (2001)] is employed, which, based on an ansatz for the xc-hole amplitude, is able to reproduce the important dynamical and nondynamical effects of Coulomb correlation through the efficient use of virtual orbitals. Self-consistent calculations require the corresponding xc potential to be obtained, to which end the optimized effective potential (OEP) method is used within the common energy denominator approximation for the static orbital Green's function. The problem of the asymptotic divergence of the xc potential of the OEP when a finite number of virtual orbitals is used is addressed. The self-consistent calculations reproduce very well the entire H-2 potential curve, describing correctly the gradual buildup of strong left-right correlation in stretched H-2. (C) 2003 American Institute of Physics.
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The construction industry notoriously excels at dispute creation – both in Ireland and world wide. This paper exams mediation in the Irish construction industry based around critical success factors in the competencies and processes required by mediators operating in the construction industry. Through conducting the relevant analysis, it was possible to extract and outline the resulting critical success factors in process and competencies of mediators in the Irish construction industry. This was achieved through a review of the literature, followed by detailed interviews from industry experts to elicit and highlight the core competencies required. To aid in the study, qualitative analysis using mind mapping software was adopted, thus assisting the identification of the key factors. Following analysis, facilitative mediation was identified as best suited for the industry in question; recommendations and experience were key for mediator selection and five and six factors were identified for mediator skills and mediation critical success factors respectively. The results returned are similar to those determined by authors in other countries and provide a good reference point for the development the industry. By following the findings of this report mediators and parties in dispute can improve processes and be more successful in outcomes. In this study the author shows that mediation is an effective and appropriate method of resolving disputes within the Irish construction industry.
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A new approach for extracting stress intensity factors (SIFs) by the element-free Galerkin (EFG) class of methods through a modified crack closure integral (MCCI) scheme is proposed. Its primary feature is that it allows accurate calculation of mode I and mode II SIFs with a relatively simple and straightforward analysis even when a coarser nodal density is employed. The details of the adoption of the MCCI technique in the EFG method are described. Its performance is demonstrated through a number of case studies including mixed-mode and thermal problems in linear elastic fracture mechanics (LEFM). The results are compared with published theoretical solutions and those based on the displacement method, stress method, crack closure integral in conjunction with local smoothing (CCI–LS) technique, as well as the M-integral method. Its advantages are discussed.
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1. Quantitative reconstruction of past vegetation distribution and abundance from sedimentary pollen records provides an important baseline for understanding long term ecosystem dynamics and for the calibration of earth system process models such as regional-scale climate models, widely used to predict future environmental change. Most current approaches assume that the amount of pollen produced by each vegetation type, usually expressed as a relative pollen productivity term, is constant in space and time.
2. Estimates of relative pollen productivity can be extracted from extended R-value analysis (Parsons and Prentice, 1981) using comparisons between pollen assemblages deposited into sedimentary contexts, such as moss polsters, and measurements of the present day vegetation cover around the sampled location. Vegetation survey method has been shown to have a profound effect on estimates of model parameters (Bunting and Hjelle, 2010), therefore a standard method is an essential pre-requisite for testing some of the key assumptions of pollen-based reconstruction of past vegetation; such as the assumption that relative pollen productivity is effectively constant in space and time within a region or biome.
3. This paper systematically reviews the assumptions and methodology underlying current models of pollen dispersal and deposition, and thereby identifies the key characteristics of an effective vegetation survey method for estimating relative pollen productivity in a range of landscape contexts.
4. It then presents the methodology used in a current research project, developed during a practitioner workshop. The method selected is pragmatic, designed to be replicable by different research groups, usable in a wide range of habitats, and requiring minimum effort to collect adequate data for model calibration rather than representing some ideal or required approach. Using this common methodology will allow project members to collect multiple measurements of relative pollen productivity for major plant taxa from several northern European locations in order to test the assumption of uniformity of these values within the climatic range of the main taxa recorded in pollen records from the region.
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Novos processos fermentativos, designados por processos de Fermentação Extractiva, são caracterizados por apresentarem etapas de produção e extracção em simultâneo. A extracção líquido-líquido como técnica de separação é amplamente usado na indústria química pela sua simplicidade, baixo custo e facilidade de extrapolação de escala. No entanto o uso de solventes orgânicos nestes processos potencia os riscos ocupacionais e ambientais. Neste contexto, o uso de sistemas de duas fases aquosas baseados em líquidos iónicos, apresenta-se como uma técnica eficaz para a separação e purificação de produtos biológicos. Este trabalho apresenta um estudo integrado sobre o uso de líquidos iónicos não aromáticos foram determinados. A capacidade para a formação de sistemas de duas fases foi estudada para uma vasta gama de líquidos iónicos hidrofílicos com diferentes aniões, catiões e cadeias alqúilicas. A capacidade de separação e purificação de um largo conjunto de líquidos iónicos foi posteriormente investigada, recorrendo-se ao uso de várias biomoléculas modelo de diferentes graus de complexidade, um amino-acido (L-triptofano) e duas enzimas lipolíticas (enzima produzida pela bactéria Bacillus sp. e Candida antarctica lipase B – CaLB). Esta última foi ainda usada para um estudo de biocompatibilidade, tendo sido determinado o efeito de diferentes LIs hidrofílicos na sua actividade enzimática. Este trabalho mostra um estudo ecotoxicológico duma vasta gama de líquidos iónicos e espécies aquáticas, inseridas em diversos níveis tróficos. A bioacumulação foi investigada através do estudo dos coeficientes de distribuição 1-octanol-água (Dow).