41 resultados para FACETS


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YPO4 nano/microcrystals with multiform crystal phases and morphologies, such as hexagonal nano/submicroprisms, spherical-like nanoparticles, and nanorods with different length/diameter ratios as well as tetragonal nanospindles, have been synthesized via a facile hydrothermal route. A series of controlled experiments indicate that the pH values in the initial solution, phosphorus sources, and the organic additive trisodium citrate (Cit(3-)) are responsible for crystal phase and shape determination of final products. It is found that Cit(3-) as a ligand and shape modifier has the dynamic effect by adjusting the growth rate of different facets under different experimental conditions, resulting in the formation of various geometries of the final products. The possible formation mechanisms for products with diverse architectures have been presented.

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LaF3. CeF3, CeF3:Tb3+, and CeF3:Tb3+ @LaF3 (core-shell) 2D nanoplates have been successfully synthesized by a facile and effective hydrothermal process. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra as well as kinetic decays were used to characterize the samples. The experimental results indicate that the organic additive, trisodium citrate (Cit(3-)), as a shape modifier has the dynamic effect by adjusting the growth rate of different crystal facets, resulting in forming the anisotropic geometries of the final products. The possible formation mechanisms for different products have been presented. The CeF3, CeF3:Tb3+, and CeF3:Tb3+ @LaF3 (core/shell) nanoplates show characteristic emission of Ce3+ (5d-4f) and Tb3+ (f-f), respectively.

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In the paper, we report an efficient method to prepare high yield (up to 97%) of silver nanoplates. Synthesis of silver nanoplates was carried Out in a binary solvent system of N,N-dimethylformamide (DMF) and toluene, in which DMF served as the reductant and polyvinylpyrrolidone (PVP) as the capping agent. By increasing the ratio of toluene to DMF to 7:6, silver nanoplates can be Successfully synthesized; otherwise other shaped nanoparticles would be the major products. The nanoplate sample was characterized by TEM, HRTEM, SAED, XRD, AFM and UV-visible spectroscopy, proving the high nanoplate purity of this sample. The influence of toluene content, other solvents, AgNO3 concentration, preparation temperature and chloride ions was also examined, which suggests that the function of nonpolar solvents in this system is to enhance the PVP coverage on silver surface and, furthermore, to facilitate the preferential adsorption of PVP on two (I I I) facets of silver nanoplates.

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Large-scale GdVO4:Eu3+ nanowires with diameters of about 15 nm and lengths of several micrometers were achieved by a facile hydrothermal method in the presence of disodium ethylenediamine tetraacetate (Na2H2L). The influences of several parameters, such as pH value, reaction temperature, and molar ratio of Na2H2L to Gd3+ on the final products were investigated. The formation mechanism of the as-obtained GdVO4:Eu3+ nanowires is proposed on the basis of time-dependent experiments. It is found that the organic additive Na2H2L, which acts as a shape modifier, has a dynamic effect by adjusting the growth rates of different facets, resulting in the formation of the GdVO4:Eu3+ nanowires. The luminescent spectrum of GdVO4:Eu3+ nanowires shows the strong characteristic dominant emission of the Eu3+ ions at 614 nm.

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beta-NaYF4 microcrystals with a variety of morphologies, such as microrod, hexagonal microprism, and octadecahedron, have been synthesized via a facile hydrothermal route. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and photoluminescence (PL) spectra were used to characterize the samples. The intrinsic structural feature of beta-NaYF4 seeds and two important external factors, namely, the pH values in the initial reaction solution and fluoride sources, are responsible for shape determination of beta-NaYF4 microcrystals. It is found that the organic additive trisodium citrate (Cit(3-)) as a shape modifier has the dynamic effect by adjusting the growth rate of different facets under different experimental conditions, resulting in the formation of the anisotropic geometries of various beta-NaYF4 microcrystals. The possible formation mechanisms for products with various architectures have been presented. A systematic study on the photoluminescence of Tb3+-doped beta-NaYF4 samples with rod, prism, and octadecahedral shapes has shown that the optical properties of these phosphors are strongly dependent on their morphologies and sizes.

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Two- and three-dimensional Au nanoparticle/[tetrakis(N-methylpyridyl)porphyrinato]cobalt (CoTMPyP) nanostructured materials were prepared by "bottom-up" self-assembly. The electrocatalytic and plasmonic properties of the Au nanoparticle/CoTMPyP self-assembled nanostructured materials (abbreviated as Au/CoTMPyP SANMs) are tunable by controlled self-assembly of the An nanoparticles and CoTMPyP on indium tin oxide (ITO) electrode. The electrocatalytic activity of the Au/CoTMPyP SANMs can be tuned in two ways. One way is that citrate-stabilized An nanoparticles are positioned first on ITO surface with tunable number density, and then positively charged CoTMPyP ions are planted selectively on these gold sites. The other way is that An nanoparticles and CoTMPyP are deposited by virtue of layer-by-layer assembly, which can also tune the amount of the as-deposited electrocatalysts. FE-SEM studies showed that three-dimensional SANMs grow in the lateral expansion mode, and thermal annealing resulted in both surface diffusion of nanoparticles and atomic rearrangement to generate larger gold nanostructures with predominant (I 11) facets.

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Single crystal nanoplates with thickness less than 30 nm, characterized by hexagonal and truncated triangular shapes bounded mainly by {111} facets, were obtained in large quantities by aspartate reduction of gold chloride.

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The catalytic decomposition of NO over Ag-ZSM-5 catalyst prepared by ion-exchange was investigated. The exchanged silver in the zeolite was reduced and it collected in the course of the reaction to form silver particles of about 20 nm. The catalytic reaction induced a pronounced restructuring of the Ag particles through preferential formation of the (111) facets. These facets were shown to hind a tightly bound oxygen species (O-gamma). The O-gamma species occupies the active sites for NO adsorption resulting in catalyst deactivation. It could be removed by appropriate reducing agents, such as CO, to recover the active sites at elevated temperatures.

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This study employed the compliance, identification, and internalization model of attitude change to explore the mechanism of rule-following behaviors in organizations. The objectives of this study were to examine the effects of individual utilitarianism and formalism on rule compliance, deference and rule-breaking behaviors, and the relationships between legitimacy, organizational identification, and value internalization. I surveyed 262 employees from a high-tech corporation in Beijing. After Confirmative Factor Analysis, Regression Analysis, and Structural Equation Modeling, I summarized main conclusions as follow. First, rule legitimacy and organizational identification have different effects on different rule behaviors. Perceived rule legitimacy and organizational identification have direct positive effect on rule deference. But the effects of legitimacy on rule-compliance and rule-breaking are moderated by organizational identification and value internalization. Only under high identification or value congruence with organization, could legitimacy perception predict rule compliance and breaking. Second, individual formalism (IF) has positive effect on rule compliance. IF’s positive effect on rule deference only appear under high value congruence between individuals and organization. Third, organizational identification works as a “valve” in the relationship between individual viewpoints and rule-breaking. Organizational identification turns off the tendency of utilitarianism to break rules, and turns on the tendency of formalism to inhibit rule-breaking. Forth, attitudinal and behavioral facets of utilitarianism and formalism have different influences on rule-following behaviors. Only individuals who are both attitudinal and behavioral formalists show deference to rules, while formalism as behavioral tendency predicts less rule-breaking. Fifth, innovation behaviors coexist independently with compliance and deference to rules. But the division between innovation and rule-breaking is obscure. Organizational identification facilitate both rule following and innovation. Sixth, women comply with rules more than men do, while men break more rules than women do. More aged people develop deeper identification with their organizations, and higher deference to rules. Individuals with higher education are fewer formalists, and accordingly defer to rules less and break more.

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Based on social survey data conducted by local research group in some counties executed in the nearly past five years in China, the author proposed and solved two kernel problems in the field of social situation forecasting: i) How can the attitudes’ data on individual level be integrated with social situation data on macrolevel; ii) How can the powers of forecasting models’ constructed by different statistic methods be compared? Five integrative statistics were applied to the research: 1) algorithm average (MEAN); 2) standard deviation (SD); 3) coefficient variability (CV); 4) mixed secondary moment (M2); 5) Tendency (TD). To solve the former problem, the five statistics were taken to synthesize the individual and mocrolevel data of social situations on the levels of counties’ regions, and form novel integrative datasets, from the basis of which, the latter problem was accomplished by the author: modeling methods such as Multiple Regression Analysis (MRA), Discriminant Analysis (DA) and Support Vector Machine (SVM) were used to construct several forecasting models. Meanwhile, on the dimensions of stepwise vs. enter, short-term vs. long-term forecasting and different integrative (statistic) models, meta-analysis and power analysis were taken to compare the predicting power of each model within and among modeling methods. Finally, it can be concluded from the research of the dissertation: 1) Exactly significant difference exists among different integrative (statistic) models, in which, tendency (TD) integrative models have the highest power, but coefficient variability (CV) ones have the lowest; 2) There is no significant difference of the power between stepwise and enter models as well as short-term and long-term forecasting models; 3) There is significant difference among models constructed by different methods, of which, support vector machine (SVM) has the highest statistic power. This research founded basis in all facets for exploring the optimal forecasting models of social situation’s more deeply, further more, it is the first time methods of meta-analysis and power analysis were immersed into the assessments of such forecasting models.

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This research aims to discuss it is the complexity of interpersonal association and job autonomy that influence the predictive validity of personality for job performance. In addition, for service profession, incumbents' personality can predict not only contextual performance, but also task performance. Salesclerks in shopping center and life insurance agents are selected as subjects. The job performance rating scale is produced by using Critical Incidents Technique. The research method is measuring NEO-PI and collecting direct supervisors' rating of salespeople's job performance. The research results are as follows: 1. The factor analysis result of job performance is different from the west. That is to say, the support for organizations which belongs to contextual performance in the west can not be distinguished from task performance. Therefore, in China, or to say in the shopping center selected, task performance includes both technical proficiency and the support for organizations, and contextual performance includes job dedication and interpersonal facilitation. 2. For salespeople, personality can be the antecedent of contextual performance and task performance as well. However, the predictive validity for task performance is very low. 3. The more complexity of interpersonal association, the stronger relationship between personality and job performance. 4a. The correlation between job performance and facets of Big Five is higher than the one between job performance and factors of Big Five, such as Agreeableness, whose facets have different impacts on job performance, some positive and others negative. 4b. The correlation between personality and the items of job performance rating scale is higher than the one between personality and the factors of job performance. 4. Working experience is the moderator of the relationship between personality and job performance. For salesclerks, only if the working experience of subjects is less than 3 years, achievement striving-one facet of conscientiousness-is significantly correlated with the ratio of finished sales volume at 0.01 level.