Crystal and electronic facet analysis of ultrafine Ni2P particles by solid-state NMR nanocrystallography

Structural and morphological control of crystalline nanoparticles is crucial in the field of heterogeneous catalysis and the development of “reaction specific” catalysts. To achieve this, colloidal chemistry methods are combined with ab initio calculations in order to define the reaction parameters, which drive chemical reactions to the desired crystal nucleation and growth path. Key in this procedure is the experimental verification of the predicted crystal facets and their corresponding electronic structure, which in case of nanostructured materials becomes extremely difficult. Here, by employing 31P solid-state nuclear magnetic resonance aided by advanced density functional theory calculations to obtain and assign the Knight shifts, we succeed in determining the crystal and electronic structure of the terminating surfaces of ultrafine Ni2P nanoparticles at atomic scale resolution. Our work highlights the potential of ssNMR nanocrystallography as a unique tool in the emerging field of facet-engineered nanocatalysts.

Crystal and Electronic Facet Analysis of Ultrafine Ni2P Particles by Solid-State NMR Nanocrystallography

Structural and morphological control of crystalline nanoparticles is crucial in the field of heterogeneous catalysis and the development of “reaction specific” catalysts. To achieve this, colloidal chemistry methods are combined with ab initio calculations in order to define the reaction parameters, which drive chemical reactions to the desired crystal nucleation and growth path. Key in this procedure is the experimental verification of the predicted crystal facet and its corresponding electronic structure, which in case of nanostructured materials becomes extremely difficult. Here, by employing ³¹P solid-state nuclear magnetic resonance (ssNMR) aided by advanced density functional theory (DFT) calculations to obtain and assign the Knight shifts, we succeeded in determining the crystal and electronic structure of the terminating surfaces of ultrafine Ni₂P nanoparticles at atomic scale resolution. Our work highlights the potential of ssNMR nanocrystallography as a unique tool in the emerging field of facet-engineered nanocatalysts.

Crystal and Electronic Facet Analysis of Ultrafine Ni2P Particles by Solid-State NMR Nanocrystallography

Structural and morphological control of crystalline nanoparticles is crucial in the field of heterogeneous catalysis and the development of “reaction specific” catalysts. To achieve this, colloidal chemistry methods are combined with ab initio calculations in order to define the reaction parameters, which drive chemical reactions to the desired crystal nucleation and growth path. Key in this procedure is the experimental verification of the predicted crystal facet and its corresponding electronic structure, which in case of nanostructured materials becomes extremely difficult. Here, by employing ³¹P solid-state nuclear magnetic resonance (ssNMR) aided by advanced density functional theory (DFT) calculations to obtain and assign the Knight shifts, we succeeded in determining the crystal and electronic structure of the terminating surfaces of ultrafine Ni₂P nanoparticles at atomic scale resolution. Our work highlights the potential of ssNMR nanocrystallography as a unique tool in the emerging field of facet-engineered nanocatalysts.

Faceted classification in support of diversity: the role of concepts and terms in representing religion

The paper examines the development of facet analysis as a methodology and the role it plays in building classifications and other knowledge-organization tools. The use of categorical analysis in areas other than library and information science is also considered. The suitability of the faceted approach for humanities documentation is explored through a critical description of the FATKS (Facet Analytical Theory in Managing Knowledge Structure for Humanities) project carried out at University College London. This research focused on building a conceptual model for the subject of religion together with a relational database and search-and-browse interfaces that would support some degree of automatic classification. The paper concludes with a discussion of the differences between the conceptual model and the vocabulary used to populate it, and how, in the case of religion, the choice of terminology can create an apparent bias in the system.

Improving the effectiveness of subject facets in library catalogs and beyond: a MARC-based semiautomated approach

PurposeThis paper puts forward a MARC-based semiautomated approach to extracting semantically rich subject facets from general and/or specialized controlled vocabularies for display in topic-oriented faceted catalog interfaces in a way that would better support users' exploratory search tasks.Design/methodology/approachHierarchical faceted subject metadata is extracted from general and/or specialized controlled vocabularies by using standard client/server communication protocols. Rigorous facet analysis, classification and linguistic principles are applied on top of that to ensure faceting accuracy and consistency.FindingsA shallow application of facet analysis and classification, together with poorly organized displays, is one of the major barriers to effective faceted navigation in library, archive and museum catalogs.Research limitations/implicationsThis paper does not deal with Web-scale discovery services.Practical implicationsThis paper offers suggestions that can be used by the technical services departments of libraries, archives and museums in designing and developing more powerful exploratory search interfaces.Originality/valueThis paper addresses the problem of deriving clearly delineated topical facets from existing metadata for display in a user-friendly, high-level topical overview that is meant to encourage a multidimensional exploration of local collections as well as “learning by browsing.”

Developing a Taxonomic Framework of Security Methods for Security Management and Information Resource Management

People who are concerned with security (such as security professionals) are naturally interested in methods of achieving security. This paper proposes an approach to creating a taxonomic framework of security methods. The taxonomic framework is developed using facet analysis based on a tetra-facet model of security, which identifies four facets of security: subject/scope of security, object of protection, source of insecurity, and method of protection. The taxonomic framework of security methods is created by combining two of the facets: source of insecurity and method of protection. The taxonomic framework of security methods can be integrated with the taxonomic framework of security (which was developed in a previous study), and can be used for security management and the management of information resources related to security and security methods.