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51.
Katrin Witting Sina Ober-Blöbaum Michael Dellnitz 《Journal of Global Optimization》2013,57(2):331-345
In contrast to classical optimization problems, in multiobjective optimization several objective functions are considered at the same time. For these problems, the solution is not a single optimum but a set of optimal compromises, the so-called Pareto set. In this work, we consider multiobjective optimization problems that additionally depend on an external parameter ${\lambda \in \mathbb{R}}$ , so-called parametric multiobjective optimization problems. The solution of such a problem is given by the λ-dependent Pareto set. In this work we give a new definition that allows to characterize λ-robust Pareto points, meaning points which hardly vary under the variation of the parameter λ. To describe this task mathematically, we make use of the classical calculus of variations. A system of differential algebraic equations will turn out to describe λ-robust solutions. For the numerical solution of these equations concepts of the discrete calculus of variations are used. The new robustness concept is illustrated by numerical examples. 相似文献
52.
Dirk K. Neumann Michael W. Hoffman Sina Balkır 《Circuits, Systems, and Signal Processing》2008,27(3):381-390
Many ultra-wideband (UWB) systems are challenged by strong jammers and narrowband interferers. Using two antennas, we demonstrate
a robust UWB radio frequency (RF) front-end design in a 0.25 μm mixed-signal complementary metal oxide semiconductor (CMOS)
technology. The proposed realization is capable of adaptively removing a high-power, narrowband interferer early in the receiver
chain avoiding front-end saturation and preserving UWB signal power. The early interferer removal resulting in interferer-free
demodulation is based on the least mean squares (LMS) algorithm and achieved through a novel combiner low-noise amplifier
and noise optimized filtering. Circuit level RF simulations of the proposed circuitry indicate a maximum improvement in signal-to-interference
ratio of 39.6 dB. 相似文献
53.
Mohamad Hasan Mohamadzadeh Moghadam Sina Sabury Mohsen Moazzami Gudarzi Farhad Sharif 《Journal of polymer science. Part A, Polymer chemistry》2014,52(11):1545-1554
Graphene oxide (GO)–polyaniline (PANI) composite is synthesized by in situ polymerization of aniline in the presence of GO as oxidant, resulting in highly crystalline and conductive composite. Fourier transform infrared spectrum confirms aniline polymerization in the presence of GO without using conventional oxidants. Scanning electron microscopic images show the formation of PANI nanofibers attached to GO sheets. X‐ray diffraction (XRD) patterns indicate the presence of highly crystalline PANI. The sharp peaks in XRD pattern suggest GO sheets not only play an important role in the polymerization of aniline but also in inducing highly crystalline phase of PANI in the final composite. Electrical conductivity of doped GO–PANI composite is 582.73 S m?1, compared with 20.3 S m?1 for GO–PANI obtained by ammonium persulfate assisted polymerization. The higher conductivity appears to be the result of higher crystallinity and/or chemical grafting of PANI to GO, which creates common conjugated paths between GO and PANI. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1545–1554 相似文献
54.
55.
Flat plates, both single and in tandem or side by side arrangement, are widely used in many engineering applications. Despite vast investigations of the flow structures and wakes downstream of these bluff bodies, this unsteady phenomenon yet remains a fundamental issue in many industrial applications. This paper reviews the state of the art concerning the flow over flat plates in different arrangements focusing on plates normal to the flow. Turbulent wake regions are discussed for the flat plates in side by side or tandem arrangement. Numerical studies are reviewed with emphasis on the realized turbulent models. The effect of the chosen turbulence model on the prediction of the wake region is discussed. 相似文献
56.
Hamzeh Eyni Mansour Jahangiri Farhoush Kiani Hasan Tahermansouri 《Journal of solution chemistry》2018,47(6):1079-1095
In this work we investigate the thermodynamic properties and pKa value of lamivudine and pefloxacin drugs, in aqueous solutions, by ab initio and density functional theory (DFT) methods at different temperatures. Molecular structures and solute–solvent effects of the anions, cations, and neutral molecules of lamivudine and pefloxacin were studied by the polarizable continuum model (PCM). The calculation was done at the DFT-B3LYP/6-31+G(d) level of theory using Tomasi’s method to analyze the formation of intermolecular hydrogen bonds (IHB) in aqueous solution. The pKa1 values of lamivudine and pKa2 values of pefloxacin increase with temperature increase. In contrast, the pKa1 values of pefloxacin decrease when the temperature increases. Further, the thermodynamic properties of the ionization processes (?H, ?S and ?G) of the drugs in aqueous solution were determined and discussed. The results of this work are in good agreement with the literature data at 298.15 K. 相似文献
57.
Hai Xin Farshad Oveissi Sina Naficy Geoffrey M. Spinks 《Journal of polymer science. Part A, Polymer chemistry》2018,56(19):1287-1293
Hydrogen bonds are known to play an important role in prescribing the mechanical performance of certain hydrogels such as polyether-based polyurethanes. The quantitative contribution of hydrogen bonds to the toughness of polymer networks, however, has not been elucidated to date. Here, a new physical model is developed to predict the threshold fracture energies of hydrogels physically crosslinked via hydrogen bonds. The model is based on consecutive and sequential dissociation of hydrogen-bonded crosslinks during crack propagation. It is proposed that the scission of hydrogen bonds during crack propagation allows polymer strands in the deformation zone to partially relax and release stored elastic energy. The summation of these partial chain relaxations leads to amplified threshold fracture energies which are 10–45 times larger than those predicted by the classical Lake–Thomas theory. Experiments were performed on a hydrophilic polyurethane hydrogel where urea additions were used to control the density of hydrogen bonds. The measured fracture energies were in good agreement with the calculated values. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1287–1293 相似文献
58.
Junrong Li Alain Wuethrich Shuvashi Dey Rebecca E. Lane Abu A. I. Sina Jing Wang Yuling Wang Simon Puttick Kevin M. Koo Matt Trau 《Advanced functional materials》2020,30(37)
The field of precision oncology is rapidly progressing toward integrated “multiomics” analysis of multiple molecular species (such as DNA, RNA, or proteins) to provide a more complete profile of tumor heterogeneity. Micro/nanomaterial‐based systems, which leverage the unique properties of miniature materials, are currently well positioned to expand beyond rudimentary biomarker detection toward multiomics signature analysis. To enable clinical translation, the rational design and implementation of miniaturized systems should be driven by the unique clinical challenges present at various crucial cancer stages. This review features micro/nanomaterial‐based systems that are robustly tested on real patient samples for molecular biomarker detection at i) initial cancer screening and/or diagnosis, ii) cancer prognosis and risk stratification, and iii) longitudinal treatment/recurrence monitoring. Furthermore, this review discusses the use of micro/nanomaterials to facilitate sample preparation for different molecular biomarker species. Finally, this review deliberates on the recent paradigm shift of micro/nanomaterial‐based system innovation toward integrated multiomics cancer signature analysis and puts forth insights and perspectives on existing challenges. It is anticipated that this review could stimulate the propagation of new concepts and approaches to kick‐start a new generation of clinically translational technologies that capitalize on multiomics cancer signatures. 相似文献
59.
Wireless Networks - In this paper, a Mercedes-Benz logo antenna with a metal plate located at an optimized distance from the proposed antenna is introduced as a wearable antenna to operate in the... 相似文献
60.
Thiazole orange was synthetically incorporated into oligonucleotides by using the corresponding phosphoramidite as the building block for automated DNA synthesis. Due to the covalent fixation of the TO dye as a DNA base surrogate, the TO-modified oligonucleotides do not exhibit a significant increase of fluorescence upon hybridization with the counterstrand. However, if 5-nitroindole (NI) is present as a second artificial DNA base (two base pairs away from the TO dye) a fluorescence increase upon DNA hybridization can be observed. That suggests that a short-range photoinduced electron transfer causes the fluorescence quenching in the single strand. The latter result represents a concept that can be transferred to the commercially available Cy3 label. It enables the Cy3 fluorophore to display the DNA hybridization by a fluorescence increase that is normally not observed with this dye. 相似文献