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排序方式: 共有431条查询结果,搜索用时 15 毫秒
1.
Fouad Erchiqui 《Polymer Engineering and Science》2005,45(10):1319-1335
The problem of modeling and the dynamic finite element simulation of thermoforming process for viscoelastic sheet are considered. The pressure load used in modeling is thus deduced from the thermodynamic law of ideal gases. The viscoelastic behavior of the K‐BKZ model is considered. The Lagrangian formulation together with the assumption of the membrane theory is used in the finite element implementation. The numerical validation is performed by comparing the theoretical solution for the uniaxial and equibiaxial hencky deformation with numerical results. Moreover, the influence of the K‐BKZ constitutive model, for three linear time distribution of airflow rate loading, on the thickness and on the stress distribution in thermoforming of containers made of HDPE are analyzed. POLYM. ENG. SCI., 45:1319–1335, 2005. © 2005 Society of Plastics Engineers 相似文献
2.
Feruglio S. Fouad Hanna V. Alquie G. Vasilescu G. 《IEEE transactions on instrumentation and measurement》2006,55(6):1892-1903
In this paper, analytical expressions of dark currents and equivalent noise generators of a CMOS color image sensor are presented, and the signal-to-noise ratio (SNR) at both outputs is evaluated. Static measurements and simulations on Austria Micro Systems 0.35-mum CMOS test structures yield guidelines to increase the SNR of the buried double junction photodetector 相似文献
3.
CE Lewis V George M Fouad V Porter D Bowen N Urban 《Canadian Metallurgical Quarterly》1998,19(5):461-476
The Women's Health Trial:Feasibility Study in Minority Populations (WHT:FSMP) examined the feasibility of recruiting postmenopausal women from a broad range of racial and socioeconomic backgrounds into a primary prevention trial requiring marked reductions in dietary fat. Postmenopausal women aged 50-79 yr who had no history of cardiovascular disease or cancer and who consumed 36% or more total energy from fat qualified to participate. We randomized the women into dietary intervention (60%) or control (40%) groups; we aimed to randomize 750 women in 18 months in each of the three clinical centers. All centers achieved goals for randomization based on ethnicity, and two centers exceeded overall recruitment goals. The greatest source of randomized participants was mass mailing, followed by items in the media, referrals, and community outreach. Recruitment yields were generally similar for the ethnic groups but lower for less-educated participants. The experience of WHT:FSMP indicates that postmenopausal women from the African-American, Hispanic, and non-Hispanic white communities can be recruited into dietary intervention studies for the prevention of disease. 相似文献
4.
M. Amine Abou-State Fouad F. Abd El-Megeid 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1972,22(9):993-999
Egyptian cotton linters were pulped by the nitric acid process. In order to reduce the high ash and silica contents of the resulting pulps it was found necessary to apply hot refining with sodium hydroxide solution. Different conditions of concentration, temperature, and pressure in the refining step were investigated. Refining before and during bleaching were compared. 相似文献
5.
Lin Wang Xianju Xie Michael D. Weir Ashraf F. Fouad Liang Zhao Hockin H. K. Xu 《Journal of materials science. Materials in medicine》2016,27(11):168
The objectives of this study were to: (1) develop a new bioactive dental bonding agent with nanoparticles of amorphous calcium phosphate and dimethylaminohexadecyl methacrylate for tooth root caries restorations and endodontic applications, and (2) investigate biofilm inhibition by the bioactive bonding agent against eight species of periodontal and endodontic pathogens for the first time. Bonding agent was formulated with 5?% of dimethylaminohexadecyl methacrylate. Nanoparticles of amorphous calcium phosphate at 30?wt% was mixed into adhesive. Eight species of biofilms were grown on resins: Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Parvimonas micra, Enterococcus faecalis, Enterococcus faecium. Colony-forming units, live/dead assay, biomass, metabolic activity and polysaccharide of biofilms were determined. The results showed that adding dimethylaminohexadecyl methacrylate and nanoparticles of amorphous calcium phosphate into bonding agent did not decrease dentin bond strength (P?>?0.1). Adding dimethylaminohexadecyl methacrylate reduced the colony-forming units of all eight species of biofilms by nearly three orders of magnitude. The killing efficacy of dimethylaminohexadecyl methacrylate resin was: P. gingivalis?>?A. actinomycetemcomitans?>?P. intermedia?>?P. nigrescens?>?F. nucleatum?>?P. micra?>?E. faecalis?>?E. faecium. Dimethylaminohexadecyl methacrylate resin had much less biomass, metabolic activity and polysaccharide of biofilms than those without dimethylaminohexadecyl methacrylate (P?<?0.05). In conclusion, a novel dental adhesive was developed for root caries and endodontic applications, showing potent inhibition of biofilms of eight species of periodontal and endodontic pathogens, and reducing colony-forming units by three orders of magnitude. The bioactive adhesive is promising for tooth root restorations to provide subgingival margins with anti-periodontal pathogen capabilities, and for endodontic sealer applications to combat endodontic biofilms. 相似文献
6.
7.
Ali Fouad Keith Phalp John Mathenge Kanyaru Sheridan Jeary 《Software Quality Journal》2011,19(2):411-430
Model-Driven Architecture (MDA) brings benefits to software development, among them the potential for connecting software
models with the business domain. This paper focuses on the upstream or Computation-Independent Model (CIM) phase of MDA. Our contention is that, whilst there are many models and notations available
within the CIM phase, those that are currently popular and supported by the Object Management Group (OMG) may not be the most
useful notations for business analysts nor sufficient to fully support software requirements and specification. Therefore,
with specific emphasis on the value of the Business Process Modelling Notation (BPMN) for business analysts, this paper provides
an example of a typical CIM approach before describing an approach that incorporates specific requirements techniques. A framework
extension to MDA is then introduced, which embeds requirements and specification within the CIM, thus further enhancing the
utility of MDA by providing a more complete method for business analysis. 相似文献
8.
In this paper we formulate power systems as nonlinear nearly Hamiltonian systems. Using the invariance principle for ordinary differential equations, necessary and sufficient conditions for asymptotic stability are established and a new method of estimating the domain of attraction of the stable equilibrium point is developed. The present results constitute a novel approach to stability analysis and involve the following three steps:
- Given a system with dissipation, the stability of its equilibrium is ascertained by determining the stability of the associated conservative system.
- Attractivity of the stable equilibrium of the entire system (with dissipation) is determined from the system topology.
- An estimate of the domain of attraction of the asymptotically stable equilibrium is obtained by making use of results obtained in (a) and (b).
9.
S. S. Fouad E. A. A. El-Shazly M. R. Balboul S. A. Fayek M. S. El-Bana 《Journal of Materials Science: Materials in Electronics》2006,17(3):193-198
The optical properties of As30Se70-xSnx with (x = 0, 1, 2 and 3 at Sn %) thin films have been investigated. The films used in these studies were thermally evaporated. The
structural characterization revealed that the as-deposited films were amorphous in nature. The spectral and optical parameters
have been investigated using spectrophotometric measurements of transmittance in the wavelength range (200–1100 nm). The optical
constants were determined from the interference maxima and minima using the Swanepole method. The dispersion of the refractive
index is discussed in terms of the single-oscillator Wemple-Didomenico model. The optical-absorption edge and the optical
band gap are calculated from the absorption coefficient values using the non direct transition model proposed by Tauc’s extrapolation
procedure. The relation between the optical gap and chemical composition in As-Se-Sn glassy system is discussed in terms of
the average heat of atomization Hs and the average coordination number Nc. 相似文献
10.
The sludge production and settleability have been estimated experimentally in a completely mixed biofilm-activated sludge reactor (hybrid reactor). A steady-state hybrid reactor was run at different stages of suspended biomass concentration (X) under constant values of influent substrate concentration (So) and hydraulic retention time (HRT). The values of X were gradually decreased in these stages until the system completely washed out of the suspended biomass and converted to pure biofilm reactor. As a result, the role of biofilm in the treatment gradually increased with an increase in the effluent substrate concentration (S). The experiment was supported by a mathematical expression for describing the sludge yield in the system under the previous conditions. The experimental and theoretical studies in the present work reveal that there is a critical phase of the hybrid system at which the system produces a high rate of excess sludge. That critical phase is found at a specific ratio between the suspended and the attached growth. Avoiding that critical phase enables the sludge production in the hybrid reactor to be reduced and optimized. Further, the minimum sludge production was found when the biofilm is theoretically inactive for chemical oxygen demand (COD) removal (S相似文献