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排序方式: 共有831条查询结果,搜索用时 15 毫秒
31.
Gabriela Sacarescu Elena Taran Bogdan C Donose Mihaela Simionescu Valeria Harabagiu Liviu Sacarescu 《Polymer International》2012,61(12):1726-1732
To produce surface plasmons, silver nanoparticles are synthesized in situ in a pseudo‐template system based on polyhydrosilanes. Adsorption on the silver nanoparticle surface produces a thin layer of polymer with properties different from those of bulk polysilane. The metal‐adsorbed polymer layer serves as a spacer between the polysilane fluorophore and the plasmonic nanoparticle. This prevents quenching of the polysilane emission and leads to a strong surface‐enhanced fluorescence through coupling of surface plasmons having a resonance frequency that matches the emission frequency of the polymeric emitter. Copyright © 2012 Society of Chemical Industry 相似文献
32.
This paper introduces a new facet of social media, namely that depicting social interaction. More concretely, we address this
problem from the perspective of nonverbal behavior-based analysis of competitive meetings. For our study, we made use of “The
Apprentice” reality TV show, which features a competition for a real, highly paid corporate job. Our analysis is centered
around two tasks regarding a person’s role in a meeting: predicting the person with the highest status, and predicting the
fired candidates. We address this problem by adopting both supervised and unsupervised strategies. The current study was carried
out using nonverbal audio cues. Our approach is based only on the nonverbal interaction dynamics during the meeting without
relying on the spoken words. The analysis is based on two types of data: individual and relational measures. Results obtained
from the analysis of a full season of the show are promising (up to 85.7% of accuracy in the first case and up to 92.8% in
the second case). Our approach has been conveniently compared with the Influence Model, demonstrating its superiority. 相似文献
33.
Initial moisture and pre-wetting method influence on the water absorption of recycled concrete aggregates (RCA) have been studied experimentally. For this purpose, RCA were pre-wetted by three methods: soaking under partial vacuum (simulating long term wetting), soaking under atmospheric pressure, and spraying (simulating short term wetting). The results show that the same initial amount of water in two samples of RCA do not lead to the same total amount of water absorbed by RCA during 5–120 min. The latter depends on the way they have been pre-wetted (either long term or short term). It is suggested that this phenomenon is related to the accessibility filled pores in the different pre-wetting methods. So, the pre-wetting history of RCA could change the amount of total water absorbed by the RCA up to 1%. When mixing and casting concrete are produced with RCA, the corresponding error in the determination of the effective water should have adverse effects on the fresh and hardened concrete characteristics. In this study real applications on mixtures of recycled concrete have been carried out, where the influence of initial moisture content and pre-wetting history of RCA on fresh recycled concrete properties (slump) have been investigated. 相似文献
34.
Amalia Mesaros Cristina D. Ghitulica Mihaela Popa Raluca Mereu Adriana Popa Traian Petrisor Jr. Mihai Gabor Adrian Ionut Cadis Bogdan S. Vasile 《Ceramics International》2014
Zn1−xCoxO (x==0.05, 0.10, 0.15) nanoparticles have been synthesized by an alternative wet-chemical synthesis route using the SimAdd technique. The as-obtained powders were investigated by FT-IR spectroscopy, X-ray diffraction and thermal analysis correlated with evolved gas analysis (TG–DTA–FT-IR) in order to determine their chemical nature, crystalline structure and to establish the decomposition sequences. The precipitates are generally amorphous, but low-intensity reflection peaks assigned both to the zinc oxalate dihydrate, and zinc hydroxide can be observed in the recorded patterns, indicating that hydroxy-oxalate precipitates were obtained. The structure, morphology and magnetic properties of the thermally treated samples have been investigated by X-ray diffraction, FT-IR, HRTEM, SAED, UV–vis and EPR. XRD studies reveal a hexagonal wurtzite-type structure for all Zn1−xCoxO samples. TEM investigations show particle size between 28 and 37 nm, with spherical and polyhedral shapes and with tendency to form aggregates. The presence of a Co3O4 secondary phase was evidenced by XRD, UV–vis and EPR for the Zn0.85Co0.15O sample. The ferromagnetic behavior of the samples was revealed. The paper highlights that by varying the cobalt concentration it is possible to modulate the structural, morphological, optical and magnetic properties. 相似文献
35.
Bogdan Korel 《Software Testing, Verification and Reliability》1992,2(4):203-213
Test data generation in program testing is the process of identifying a set of test data which satisfies a given testing criterion. Existing pathwise test data generators proceed by selecting program paths that satisfy the selected criterion and then generating program inputs for these paths. One of the problems with this approach is that unfeasible paths are often selected; as a result, significant computational effort can be wasted in analysing those paths. In this paper, an approach to test data generation, referred to as a dynamic approach for test data generation, is presented. In this approach, the path selection stage is eliminated. Test data are derived based on the actual execution of the program under test and function minimization methods. The approach starts by executing a program for an arbitrary program input. During program execution for each executed branch, a search procedure decides whether the execution should continue through the current branch or an alternative branch should be taken. If an undesirable execution flow is observed at the current branch, then a real-valued function is associated with this branch, and function minimization search algorithms are used to locate values of input variables automatically, which will change the flow of execution at this branch. 相似文献
36.
Dr. Lilia Clima Bogdan Florin Craciun Dr. Andrea Angeli Andrea Petreni Alessandro Bonardi Dr. Alessio Nocentini Dr. Fabrizio Carta Prof. Paola Gratteri Prof. Mariana Pinteala Prof. Claudiu T. Supuran 《ChemMedChem》2020,15(21):2052-2057
We report novel molecules incorporating the nontoxic squalene scaffold and different carbonic anhydrase inhibitors (CAIs). Potent inhibitory action, in the low-nanomolar range, was detected against isoforms hCA II for sulfonamide derivatives, which proved to be selective against this isoform over the tumor-associate hCA IX and XII isoforms. On the other hand, coumarin derivatives showed weak potency but high selectivity against the tumor-associated isoform CA IX. These compounds are interesting candidates for preclinical evaluation in glaucoma or various tumors in which the two enzymes are involved. In addition, an in silico study of inhibitor-bound hCA II revealed extensive interactions with the hydrophobic pocket of the active site and provided molecular insights into the binding properties of these new inhibitors. 相似文献
37.
Bogdan M. Leu Hasan Yavaş Innokenty Kantor Vitali B. Prakapenka 《Journal of the American Oil Chemists' Society》2010,87(12):1517-1520
We measured the velocity of sound in olive oil under pressure with the Brillouin light scattering technique. Using the values
for the density and the thermal conductivity that have only recently been reported, we calculated the adiabatic compressibility
and the isobaric specific heat up to 356 MPa and the thermal diffusivity up to 200 MPa. The specific heat displays a maximum
at 124 MPa, suggesting a possible phase transition around this pressure. Apart from the theoretical and practical importance
of these results for the food industry and beyond, this work shows that Brillouin light scattering and macroscopic methods
are complementary and can be employed to measure thermophysical parameters of food liquids under pressure. 相似文献
38.
Coordination‐Assisted Bioorthogonal Chemistry: Orthogonal Tetrazine Ligation with Vinylboronic Acid and a Strained Alkene 下载免费PDF全文
Selma Eising Dr. Bo‐Tao Xin Fleur Kleinpenning Jurriaan J. A. Heming Dr. Bogdan I. Florea Prof. Dr. Herman S. Overkleeft Dr. Kimberly M. Bonger 《Chembiochem : a European journal of chemical biology》2018,19(15):1648-1652
Bioorthogonal chemistry can be used for the selective modification of biomolecules without interfering with any other functionality that might be present. Recent developments in the field include orthogonal bioorthogonal reactions to modify multiple biomolecules simultaneously. During our research, we observed that the reaction rates for the bioorthogonal inverse‐electron‐demand Diels–Alder (iEDDA) reactions between nonstrained vinylboronic acids (VBAs) and dipyridyl‐s‐tetrazines were exceptionally higher than those between VBAs and tetrazines bearing a methyl or phenyl substituent. As VBAs are mild Lewis acids, we hypothesised that coordination of the pyridyl nitrogen atom to the boronic acid promoted tetrazine ligation. Herein, we explore the molecular basis and scope of VBA–tetrazine ligation in more detail and benefit from its unique reactivity in the simultaneous orthogonal tetrazine labelling of two proteins modified with VBA and norbornene, a widely used strained alkene. We further show that the two orthogonal iEDDA reactions can be performed in living cells by labelling the proteasome by using a nonselective probe equipped with a VBA and a subunit‐selective VBA bearing a norbornene moiety. 相似文献
39.
Bogdan M. Diaconu 《Energy and Buildings》2009,41(2):212-219
Over the last years the use of phase change slurries (PCSs) based on microencapsulated phase change material (MEPCM) increased considerably due to their capacity of adaptation to various heat storage systems. PCSs are obtained by dispersing a microencapsulated PCM (particle diameter 5-20 μm) into a heat carrier fluid (e.g. water). Heat storage systems are used in applications where the available energy supply is not synchronous with the demand, such as solar thermal and waste heat recovery systems. The theoretical study conducted here - based on heat transfer and energy conservation equations - is intended to developing a theoretical model of the heat storage properties of phase change slurries capable of predicting the transient thermal response of a thermal energy storage system (TES). Most of the research work was focused on investigating the enthalpy-temperature curves resulting from a heating-cooling cycle around the melting point of the PCM. The influence of other parameters such as mico-particles diameter was assessed. 相似文献
40.