bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluating advanced search interfaces using established information‐seeking models
Authors: Wilson Max L. , schraefel m.c. , White Ryen W. 
Published: April 2009

AbstractWhen users have poorly defined or complex goals, search interfaces that offer only keyword‐searching facilities provide inadequate support to help them reach their information‐seeking objectives. The emergence of interfaces with more advanced capabilities, such as faceted browsing and result clustering, can go some way toward addressing such problems. The evaluation of these interfaces, however, is challenging because they generally offer diverse and versatile search environments that introduce overwhelming amounts of independent variables to user studies; choosing the interface object as the only independent variable in a study would reveal very little about why one design outperforms another. Nonetheless, if we could effectively compare these interfaces, then we would have a way to determine which was best for a given scenario and begin to learn why. In this article, we present a formative inspection framework for the evaluation of advanced search interfaces through the quantification of the strengths and weaknesses of the interfaces in supporting user tactics and varying user conditions. This framework combines established models of users and their needs and behaviors to achieve this. The framework is applied to evaluate three search interfaces and demonstrates the potential value of this approach to interactive information retrieval evaluation.
Brand and its effect on user perception of search engine performance
Authors: Jansen Bernard J. , Zhang Mimi , Schultz Carsten D. 
Published: April 2009

AbstractIn this research we investigate the effect of search engine brand on the evaluation of searching performance. Our research is motivated by the large amount of search traffic directed to a handful of Web search engines, even though many have similar interfaces and performance. We conducted a laboratory experiment with 32 participants using a 42 factorial design confounded in four blocks to measure the effect of four search engine brands (Google, MSN, Yahoo!, and a locally developed search engine) while controlling for the quality and presentation of search engine results. We found brand indeed played a role in the searching process. Brand effect varied in different domains. Users seemed to place a high degree of trust in major search engine brands; however, they were more engaged in the searching process when using lesser‐known search engines. It appears that branding affects overall Web search at four stages: (a) search engine selection, (b) search engine results page evaluation, (c) individual link evaluation, and (d) evaluation of the landing page. We discuss the implications for search engine marketing and the design of empirical studies measuring search engine performance.
New Energetic Materials: Functionalized 1‐Ethyl‐5‐aminotetrazoles and 1‐Ethyl‐5‐nitriminotetrazoles
Authors: Stierstorfer Jörg , Tarantik Karina R. , Klapötke Thomas M. 
Published: April 2009

AbstractA new way to make a bang: Several functionalized 1‐ethyl‐5‐aminotetrazoles, 1‐ethyl‐5‐nitrimino‐tetrazoles, and copper complexes have been synthesized and their chemical and energetic properties have been comprehensively characterized. The compounds belong to all classes of “energetic materials”: explosives, propellants, and pyrotechnics.magnified imageAlkylation of 5‐aminotetrazole (1) with 2‐chloroethanol leads to a mixture of the N‐1 and N‐2 isomers of (2‐hydroxyethyl)‐5‐aminotetrazole. Treatment of 1‐(2‐hydroxyethyl)‐5‐aminotetrazole (2) with SOCl2 yielded 1‐(2‐chlorethyl)‐5‐aminotetrazole (3). 1‐(2‐Azidoethyl)‐5‐aminotetrazole (4) was generated by the reaction of 3 with sodium azide. Nitration of 2, 3, and 4 with HNO3 (100 %) yielded in the case of 2 and 3 1‐(2‐hydroxyethyl)‐5‐nitriminotetrazole (5) and 1‐(2‐chloroethyl)‐5‐nitriminotetrazole (6). In the case of 4, 1‐(2‐nitratoethyl)‐5‐nitriminotetrazole monohydrate (7) was obtained. 1‐(2‐Azidoethyl)‐5‐nitriminotetrazole (8) could be obtained by nitration of 4 with NO2BF4 via the formation of potassium 1‐(2‐azidoethyl)‐5‐nitriminotetrazolate (9). The reaction of 6 with NaN3 resulted in the formation of the salt sodium 1‐(2‐chloroethyl)‐5‐nitriminotetrazolate (10 a). The deprotonation reaction of 6 was further investigated by the formation of the ammonium salt (10 b). The protonation of 2 and 4 with dilute nitric acid led to 1‐(2‐hydroxyethyl)‐5‐aminotetrazolium nitrate (11) and 1‐(2‐azidoethyl)‐5‐aminotetrazolium nitrate (12), respectively. Similarly, protonation of 4 with perchloric acid led to 1‐(2‐azidoethyl)‐5‐aminotetrazolium perchlorate monohydrate (13). Since 5‐nitrimino‐tetrazoles can be used as bidentate ligands, the coordination abilities of 5, 6, and 8 were tested by the reaction with copper nitrate trihydrate, yielding the copper complexes trans‐[diaquabis{1‐(2‐hydroxyethyl)‐5‐nitriminotetrazolato‐κ2N4,O5}copper(II)] (14), trans‐[diaquabis{1‐(2‐chloroethyl)‐5‐nitriminotetrazolato‐κ2N4,O5}copper(II)] dihydrate (15), and [diaquabis{1‐(2‐azidoethyl)‐5‐nitriminotetrazolato‐κ2N4,O5}copper(II)] (16). All compounds were characterized by low‐temperature single‐crystal X‐ray diffraction. In addition, comprehensive characterization (IR, Raman, and multinuclear NMR spectroscopy (1H, 13C), elemental analysis, mass spectrometry, DSC) was performed. The heats of formation of selected compounds were computed by using heats of combustion obtained by bomb calorimetry or calculated by the atomization method. With these values and the densities determined from X‐ray crystallography, several detonation parameter were calculated by the EXPLO5 program. Finally, the sensitivities towards impact and friction were determined using a BAM drop hammer and friction tester.
Peptide‐Coated Silver Nanoparticles: Synthesis, Surface Chemistry, and pH‐Triggered, Reversible Assembly into Particle Assemblies
Authors: Graf Philipp , Mantion Alexandre , Foelske Annette , Shkilnyy Andriy , Mašić Admir , Thünemann Andreas F. , Taubert Andreas 
Published: April 2009

AbstractThe degree of aggregation of silver nanoparticles can be controlled via a pH sensitive peptide coating (see figure). As the peptide not only controls the colloidal properties, but also influences the crystal structure of the individual nanoparticles, peptide/silver particle hybrid materials can be viewed as flexible and simple building blocks for the construction of new meta‐materials with tunable properties.magnified imageSimple tripeptides are scaffolds for the synthesis and further assembly of peptide/silver nanoparticle composites. Herein, we further explore peptide‐controlled silver nanoparticle assembly processes. Silver nanoparticles with a pH‐responsive peptide coating have been synthesized by using a one‐step precipitation/coating route. The nature of the peptide/silver interaction and the effect of the peptide on the formation of the silver particles have been studied via UV/Vis, X‐ray photoelectron, and surface‐enhanced Raman spectroscopies as well as through electron microscopy, small angle X‐ray scattering and powder X‐ray diffraction with Rietveld refinement. The particles reversibly form aggregates of different sizes in aqueous solution. The state of aggregation can be controlled by the solution pH value. At low pH values, individual particles are present. At neutral pH values, small clusters form and at high pH values, large precipitates are observed.
The Diversity of Difluoroacetylene Coordination Modes Obtained by Coupling Fluorocarbyne Ligands on Binuclear Manganese Carbonyl Sites
Authors: Liu Xian‐mei , Wang Chao‐yang , Li Qian‐shu , Xie Yaoming , King R. Bruce , Schaefer Henry F. 
Published: April 2009

AbstractOne Mn or two? The fluorocarbyne manganese carbonyl complexes [Mn(CF)(CO)n] (n=3, 4) and [Mn2(CF)2(CO)n] (n=4–7; see picture) have been investigated by density functional theory. In mononuclear complexes the CF ligand behaves very much like the NO ligand in terms of π‐acceptor strength. In binuclear complexes the two CF ligands couple in many of the low‐energy structures to form a bridging C2F2 ligand derived from difluoroacetylene.magnified imageRecent work has shown that the fluorocarbyne ligand CF, isoelectronic with the NO ligand, can be generated by the defluorination of CF3 metal complexes, as illustrated by the 2006 synthesis by Hughes et al. of [C5H5Mo(CF)(CO)2] in good yield by the defluorination of [C5H5Mo(CF3)(CO)3]. The fluorocarbyne ligand has now been investigated as a ligand in the manganese carbonyl complexes [Mn(CF)(CO)n] (n=3, 4) and [Mn2(CF)2(CO)n] (n=4–7) by using density functional theory. In mononuclear complexes, such as [Mn(CF)(CO)4], the CF ligand behaves very much like the NO ligand in terms of π‐acceptor strength. However, in the binuclear complexes the two CF ligands couple in many of the low‐energy structures to form a bridging C2F2 ligand derived, at least formally, from difluoroacetylene, FCCF. The geometries of such [Mn2(C2F2)(CO)n] complexes suggest several different bonding modes of the bridging C2F2 unit. These include bonding through the orthogonal π bonds of FCCF, similar to the well‐known [R2C2Co2(CO)6] complexes, or bonding of the C2F2 unit as a symmetrical or unsymmetrical biscarbene. This research suggests that fluorocarbyne metal chemistry can serve as a means for obtaining a variety of difluoroacetylene metal complexes, thereby avoiding the need for synthesizing and handling the very unstable difluoroacetylene.
Structural and Reactivity Studies of “Pincer” Pyridine Dicarbene Complexes of Fe0: Experimental and Computational Comparison of the Phosphine and NHC Donors
Authors: Danopoulos Andreas A. , Pugh David , Smith Hayley , Saßmannshausen Jörg 
Published: April 2009

AbstractPincer carbene complexes: Comparison of the electronic structures of “pincer” Fe0pyridine bis(imidazol‐2‐ylidene) and pyridine diphosphine dicarbonyl complexes (see figure) show subtle differences that account for observed spectroscopic trends. Intermolecular CH activation has been observed in Fe pyridine dicarbene complexes.magnified imageReduction of [Fe(C‐N‐C)(Br)2] or [Fe(C‐NMe‐C)(I)2] with Na/Hg under N2gave the Fe0complexes [Fe(C‐N‐C)(N2)2] and [Fe(C‐NMe‐C)(N2)2] for which C‐N‐C=2,6‐bis(arylimidazol‐2‐ylidene)‐pyridine, C‐NMe‐C=2,6‐bis(arylimidazol‐2‐ylidene)‐3,5‐dimethyl‐pyridine and aryl=2,6‐iPr2C6H3. Substitution of the coordinated N2by CO or CN(2,6‐xyl), xyl=2,6‐dimethylphenyl, took place readily to afford [Fe(C‐N‐C)(L)2] and [Fe(C‐NMe‐C)(L)2], L=CO or CN(2,6‐xyl). The electronic characteristics of the N‐heterocyclic carbene and phosphine donors in the complexes [Fe(C‐N‐C)(CO)2], [Fe(C‐NMe‐C)(CO)2] and [Fe(P‐N‐P)(CO)2], P‐N‐P=2,6‐bis(di‐tert‐butylphosphinomethyl)‐pyridine, have been evaluated by spectroscopic, structural and computational methods. The unexpected reduced Fe0to CO backbonding in [Fe(C‐N‐C)(CO)2] and [Fe(C‐NMe‐C)(CO)2] compared to [Fe(P‐N‐P)(CO)2] is accounted for by backbonding from the FeNpyridinebond in the imidazol‐2‐ylidene complexes. Reduction of [Fe(C‐N‐C)(Br)2] under Ar gave mixtures from which a complex with a metalated pyridine and a dangling imidazolium group was isolated. Photolysis of [Fe(C‐N‐C)(N2)2] in the presence of benzaldehyde phenylimine gave anortho‐metalated benzaldehyde phenylimine. The FeIIcomplex [Fe(C‐N‐C)(CO)(Br)2] was prepared by the reaction of [Fe(C‐N‐C)(Br)2] with CO or reduction of CO2with [Fe(C‐N‐C)(N2)2].
Hydrogen‐Release Mechanisms in Lithium Amidoboranes
Authors: Kim Dong Young , Singh N. Jiten , Lee Han Myoung , Kim Kwang S. 
Published: April 2009

AbstractHydrogen storage: In lithium amidoboranes an initial molecule of H2 is released by the formation of LiH, followed by a redox reaction of the dihydrogen bond formed between LiHδ− and NHδ+. In this dehydrogenation process, an intermolecular NB bond forms through the catalytic effect of a Li cation. After releasing the first molecule of H2, a Li cation binds to a nitrogen atom, lowering the energy barrier for the second H2 loss per lithium amidoborane dimer (see figure).magnified imageAlkali‐metal amidoboranes have been recently highlighted as materials that satisfy many of the criteria required to make hydrogen‐storage media. It is, therefore, crucial for us to understand the dehydrogenation mechanism of these materials for further development towards making successful hydrogen‐storage media. In the present study, we attempt to shed light on the mechanisms involved in the loss of one molar equivalent of H2 from solid lithium amidoboranes by using high‐level ab initio calculations of monomeric and dimeric compounds in the gas phase. In the lithium amidoborane dimer, H2 is released by the formation of LiH, which is followed by a redox reaction of the dihydrogen bond formed between the strongly basic H− in LiH and Hδ+ bonded to N. In the dehydrogenation process, the Li cation catalyzes the intermolecular NB bond formation; this could lead to new pathways for NB polymerization. After the release of the first molecule of H2, a Li cation binds to a nitrogen atom, resulting in a lowering of the energy barrier for the second dehydrogenation process per dimer. These results will be useful for the design of future hydrogen‐storage media.
Stable Electroenzymatic Processes by Catalyst Separation
Authors: Hildebrand Falk , Lütz Stephan 
Published: April 2009

AbstractDivision of labour: The rapid enzyme inactivation in the electroenzymatic synthesis of chiral alcohols has been the main obstacle for synthetic applications during the last two decades. The reasons for this inactivation have now been elucidated. The development of a water‐soluble polymeric mediator and the spatial separation of enzyme and mediator led to the first stable process and significantly improved catalyst utilisations (see picture).magnified image
Low‐Temperature Synthesis of LiBH4 by Gas–Solid Reaction
Authors: Friedrichs Oliver , Borgschulte Andreas , Kato Shunsuke , Buchter Florian , Gremaud Robin , Remhof Arndt , Züttel Andreas 
Published: April 2009

AbstractStrikingly simple: The low‐temperature and solvent‐free synthesis of LiBH4 from LiH in a borane atmosphere at ambient pressures is reported. The results indicate that the formation of BH bonds is the limiting step for the formation of LiBH4 from the elements. Therefore, the use of diborane as a starting reactant allows one to circumvent the reaction barrier for the BB bond dissociation and explains the rather moderate synthesis conditions.magnified imageThe solvent‐free synthesis of LiBH4 from LiH in a borane atmosphere at 120 °C and ambient pressures is demonstrated. The source of borane is a milled LiBH4/ZnCl2 mixture, in which Zn(BH4)2 is generated by a metathesis reaction. The yield of the reaction of about 74 % LiBH4 shows that a bulk reaction is taking place upon borane absorption by LiH. This indicates that the formation of BH bonds is the limiting step for the formation of LiBH4 from the elements. Therefore, the use of diborane as a starting reactant allows one to circumvent the reaction barrier for the BB bond dissociation and explains the rather moderate synthesis conditions.
Alkyne‐Promoted H2Loss in a Metallaborane:Nido‐to‐ClosoCluster Transformation and sp CH Bond Oxidative Addition
Authors: Álvarez Álvaro , Macías Ramón , Bould Jonathan , Cunchillos Carmen , Lahoz Fernando J. , Oro Luis A. 
Published: April 2009

AbstractA sensitive cluster: The labile rhodathiaborane [(PPh3)2(H)‐nido‐RhSB9H9(NC5H5)] combines the redox and coordinative flexibility of the {(PPh3)2(H)Rh} fragment with the capability of the 11‐vertex rhodathiaborane cluster to undergo oxidativenido‐to‐closotransformations induced by coordination of alkynes to the metal centre, which leads to hydrogenation of the triple bond, dehydrogenation of the cluster and oxidative addition of sp CH bonds.magnified image
ChemInform Abstract: An ab initio Theoretical Study of the Electronic Structure of UO2+ and [UO2(CO3)3]5‐.
Authors: Ruiperez Fernando , Danilo Cecile , Real Florent , Flament Jean‐Pierre , Vallet Valerie , Wahlgren Ulf 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: A New Polymorph with a Layered Structure ε‐CaTe2O5.
Authors: Barrier N. , Rueff J. M. , Lepetit M. B. , Contreras‐Garcia J. , Malo S. , Raveau B. 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: La16[Si8N22][SiON3]2 — A Nitridosilicate with Isolated, Corner‐Sharing and Edge‐Sharing Tetrahedra.
Authors: Schmolke Christian , Lupart Saskia , Schnick Wolfgang 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Crystal Structure of a New Small‐Pore Zirconosilicate Na2ZrSi2O7·H2O and Its Relation to Stoichiometrically and Topologically Similar Compounds.
Authors: Nikolova Rosica Petrova , Fujiwara Keiko , Nakayama Noriaki , Kostov‐Kytin Vladislav 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Crystal Chemistry and Physical Properties of the Ternary Compounds LnBC (Ln: Ce, Pr, Nd).
Authors: Babizhetskyy Volodymyr , Hiebl Kurt , Mattausch Hansjuergen , Simon Arndt 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Structure Elucidation of BaSi2O2N2 — A Host Lattice for Rare‐Earth Doped Luminescent Materials in Phosphor‐Converted (pc)‐LEDs.
Authors: Kechele Juliane A. , Oeckler Oliver , Stadler Florian , Schnick Wolfgang 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Flexible Polar Nanowires of Cs5BiP4Se12 from Weak Interactions Between Coordination Complexes: Strong Nonlinear Optical Second Harmonic Generation.
Authors: Chung In , Song Jung‐Hwan , Jang Joon I. , Freeman Arthur J. , Ketterson John B. , Kanatzidis Mercouri G. 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Vacuum Ultraviolet Spectroscopic Properties of Rare Earth (RE) (RE: Eu, Tb, Dy, Sm, Tm)‐Doped K2GdZr(PO4)3 Phosphate.
Authors: Zhang Zhi‐Jun , Yuan Jun‐Lin , Chen Hao‐Hong , Yang Xin‐Xin , Zhao Jing‐Tai , Zhang Guo‐Bin , Shi Chao‐Shu 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: A Powder Neutron Diffraction Study of the Metallic Ferromagnet Co3Sn2S2.
Authors: Vaqueiro Paz , Sobany Gerard G. 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Ferromagnetic Ordering in CeZnSn.
Authors: Hermes Wilfried , Matar Samir F. , Harmening Thomas , Rodewald Ute Ch. , Eul Matthias , Poettgen Rainer 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Low‐Lying Electronic States and Revised Thermochemistry of TiCl, TiCl2, and TiCl3.
Authors: Hildenbrand D. L. 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Crystal Structure and Phase Transitions of Sodium Potassium Niobate Perovskites.
Authors: Tellier J. , Malic B. , Dkhil B. , Jenko D. , Cilensek J. , Kosec M. 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: High‐Pressure Synthesis and Characterization of the Alkaline Earth Borate β‐BaB4O7.
Authors: Knyrim Johanna S. , Roemer S. Rebecca , Schnick Wolfgang , Huppertz Hubert 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Nd5O4Cl[AsO3]2 and Gd5O4Br3[SeO3]2: Two Lanthanoid Oxide Halides with Complex “Lone‐Pair” Oxoanions.
Authors: Kang Dong‐Hee , Wontcheu Joseph , Schleid Thomas 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis and Crystal Structure of the First Chain‐Type Nitridosilicates Ln5Si3N9 (Ln: La, Ce).
Authors: Schmolke Christian , Bichler Daniel , Johrendt Dirk , Schnick Wolfgang 
Published: April 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.