bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses, Structures, and Properties of Quinone-Bridged Calix[6]arenes
Authors: Akine Shigehisa , Goto Kei , Kawashima Takayuki 
Published: January 2005

Abstract
The quinone-bridged calix[6]arenes 1 and 2, carrying a 1,4-benzoquinone moiety in the cavity of a calixarene macrocycle, were synthesized from the corresponding p-methoxyphenol derivatives. X-ray crystallography revealed the structures of 1 and 2, in which the quinone moiety is located inside the cone-shaped calix[6]arene framework and surrounded by the lower-rim substituents. Their 1H NMR spectra showed upfield shifts of the protons on the bridging unit in comparison with reference compounds without the calixarene framework, in accordance with their crystal structures. The cyclic voltammograms of 1 and 2 showed two waves, the second ones being considerably broadened. Their reduction potentials were found to be negatively shifted in comparison with those of the reference compounds. These shifts were explained in terms of the nonbonded interaction between the ether oxygen atoms of the calixarene moiety and the quinone moiety, as well as the sterically restricted access of the counter cation to the semiquinone anion radical. Reactions of 1 with hydroxylamine and phenylhydrazine afforded the corresponding hydroquinone along with the quinone monoimine derivatives, indicating that electron transfer from the amines proceeds quickly, although the negatively shifted reduction potentials of 1 are apparently unfavorable for the electron transfer process.
Synthesis and Properties of Novel Stilbazolium Analogues as Second-Order Nonlinear Optical Chromophores
Authors: Tsuji Kyoko , Nishimura Naoyuki , Duan Xuan-Ming , Okada Shuji , Oikawa Hidetoshi , Matsuda Hiro , Nakanishi Hachiro 
Published: January 2005

Abstract
This study synthesized a series of methoxystilbazolium analogues with π-conjugation extended by attaching a fused aromatic ring, i.e., 6-styrylisoquinolinium and 4-[2-(2-naphthyl)ethenyl]pyridinium derivatives with methoxy substituents. We evaluated their transition energies (Eegs) and second-order hyperpolarizabilities (βs) experimentally using their absorption spectra and a hyper-Rayleigh scattering measurement, respectively. Subsequently, we calculated βs using the MOPAC PM3 method. These values were compared with those of 4-[4-(4-methoxyphenyl)-1,3-butadienyl]pyridinium derivative, which is a stilbazolium analogue with π-conjugation that is simply extended by an increase of the double-bond number between two aromatic rings. This study clarified that the fused-ring systems possess large βs, irrespective of their relatively short absorption wavelengths, compared to the double-bond elongation system.
Redox Properties and Basicity of Keggin-Type Polyoxometalate Complexes
Authors: Himeno Sadayuki , Takamoto Masayo , Santo Ryoko , Ichimura Akio 
Published: January 2005

Abstract
For Keggin-type polyoxometalate complexes (α-[XMo12O40]n− (X = S, P, As, Si, Ge; n = 2–4) and α-[XW12O40]n− (X = S, P, As, Si, Ge, B, Al; n = 2–5)), the conversion processes of the first two one-electron waves into a two-electron wave were investigated in dipolar aprotic solvents containing H+, Li+, or Na+ as a Lewis acid. A simulation of the cyclic voltammogram indicated that the potential difference (ΔEmid) between the first one- and two-electron redox waves served as a useful criterion for the basicity of the Keggin anions. According to the ΔEmid values, the Keggin anions were classified into the following four groups: (1) [SW12O40]2−; (2) [SMo12O40]2−, [XW12O40]3− (X = P, As); (3) [XMo12O40]3− (X = P, As), [XW12O40]4− (X = Si, Ge); (4) [XMo12O40]4− (X = Si, Ge), [XW12O40]5− (X = B, Al). The voltammetric properties of the Keggin anions were systematized with reference to their basicities.
Preparation of Tetrahedral Pt Nanoparticles Having {111} Facet on Their Surface
Authors: Miyazaki Akane , Yoshida Shuichiro , Nakano Yoshio , Balint Ioan 
Published: January 2005

Abstract
{100} and {111} facets are typical for metal clusters having FCC structure. We have ever succeeded to obtain square Pt particles having {100} facet on their surface. However, there has not been an effective method to obtain Pt nanoparticles with the other facets, i.e., {111}. In this paper we report a novel preparation method of tetrahedral Pt nanoparticles, whose surface is controlled {111}, by using a thermosensitive capping polymer [poly(N-ethylacrylamide)].
Activation of Urea as a Leaving Group in Substitution Reactions of Formamidine Ureas
Authors: Díaz David D , Lewis Warren G , Finn M G 
Published: January 2005

Abstract
The reactions of formamidine ureas with amines take different paths under protic vs. nonprotic conditions; loss of the urea fragment has been observed for the first time when protons are made available intra- or intermolecularly.
Petrochemicals, Feedstocks
Authors: Boepple John T. 
Published: January 2005

Abstract
Petrochemicals are derived from natural gas or petroleum and can be broadly classified as olefins or aromatics. The choice of feedstock for a given operator is primarily an economic issue, but may be constrained by technical considerations or local availability of indigenous hydrocarbons. Feedstock economics are influenced by fuels products markets and the seasonal effects in fuels prices. Olefins are produced primarily by the thermal cracking of hydrocarbon feedstocks such as ethane, propane, naphtha, or gas oil. In the United States, the most important olefin feedstocks are ethane and propane, which are recovered from natural gas, whereas in most of the rest of the world naphthas are the dominant feedstocks. Lesser quantities of olefins, primarily propylene, are produced from refinery gas streams. Aromatics are recovered from refinery catalytic reformer operations and pyrolysis gasoline from olefin plants based on naphtha or gas oil feedstock. In the United States, reformer operations are the most important source; in the rest of the world, pyrolysis gasoline is the dominant feedstock. Although alternative feedstocks have been the subject of much research, only minimal usage can be expected over the coming decades.
Poly(Fluorosilicones)
Authors: Romenesko David J. , Chorvath Igor , Olsen Charles W. , Tonge Lauren M. 
Published: January 2005

AbstractPoly(fluorosilicones) are siloxane polymers with fluorinated organic substituents bonded to silicon. The combination of fluoro‐organic and siloxane properties in one material has many unique applications. The monomer and polymer preparations are reviewed for the manufacture of poly(3,3,3‐trifluoropropyl)methylsiloxane and related poly(fluorosilicones). The polymers and their materials' application properties are discussed with a correlation to chemical structure and stability. The processing, compounding, and curing of the poly(fluorosilicones) into fluids, sealants, rubber, and related applications are described, along with information on safe handling characteristics. Specific examples of applications are covered. An estimation of global capacity is given along with a perspective on market aspects.
Nonwoven Fabrics, Staple Fibers
Authors: Chapman Roger 
Published: January 2005

Abstract
This article provides an overview of the production methods, properties, and uses of nonwoven fabrics. The discussion includes a brief introduction, short history, and compilation of definitions of a nonwoven fabric. Staple fiber processes, including fiber selection, web formation, web layering, web consolidation, and finishing, are described. Descriptions and illustrations of the manufacturing sequences follow. Production trends and product applications are discussed.
Process Design
Authors: Smith Robin 
Published: January 2005

Abstract
Chemical process design requires the selection of a series of processing steps and their integration to form a complete manufacturing system. Once a structure for the process has been established, then a mathematical model of the process can be developed and the process simulated. The type of product, scale of production, and life cycle of the product have major influences on the priorities in chemical process design. Short life cycles require the design of multi‐product processes.
Chemical processing should form part of a sustainable industrial activity. For chemical processing, this means that processes should use raw materials and energy as efficiently as is economic and practicable, both to prevent the production of waste that can be environmentally harmful and to preserve the reserves of raw materials and energy as much as possible. All aspects of chemical processing must feature good health and safety practice.
The design might be a new design or the retrofit of an existing process. If the design is a retrofit, then one of the objectives should be to maximize the use of existing equipment, even if it is not ideally suited to its new purpose. Both continuous and batch process operation can be used.
Transparent Poly(methyl methacrylate)/Single‐Walled Carbon Nanotube (PMMA/SWNT) Composite Films with Increased Dielectric Constants
Authors: Clayton L. M. , Sikder A. K. , Kumar A. , Cinke M. , Meyyappan M. , Gerasimov T. G. , Harmon J. P. 
Published: January 2005

AbstractPoly(methyl methacrylate)/single‐walled carbon nanotube (PMMA/SWNT) composites were prepared via in situ polymerization induced either by heat, ultraviolet (UV) light, or ionizing (gamma) radiation. The composites dissolved in methylene chloride and then cast into films exhibited enhanced transparency as compared with the melt‐blended composite material. UV/visible spectroscopy was used to quantitatively analyze the transparency of the composites. The dielectric constant (ε′) was measured via dielectric analysis (DEA) and correlated to the refractive‐index values using Maxwell's relationship. The dielectric constant increased in the composite samples as compared with the neat PMMA samples prepared by the same methods. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) provided images of the polymer–nanotube composites and single‐walled CNTs, respectively.
Li6ALa2Ta2O12 (A = Sr, Ba): Novel Garnet‐Like Oxides for Fast Lithium Ion Conduction
Authors: Thangadurai V. , Weppner W. 
Published: January 2005

AbstractOxides with the nominal chemical formula Li6ALa2Ta2O12 (A = Sr, Ba) have been prepared via a solid‐state reaction in air using high purity La2O3, LiOH·H2O, Sr(NO3)2, Ba(NO3)2, and Ta2O5 and are characterized by powder X‐ray diffraction (XRD) in order to identify the phase formation and AC impedance to determine the lithium ion conductivity. The powder XRD data of Li6ALa2Ta2O12 show that they are isostructural with the parent garnet‐like compound Li5La3Ta2O12. The cubic lattice parameter was found to increase with increasing ionic size of the alkaline earth ions (Li6SrLa2Ta2O12: 12.808(2) Å; Li6BaLa2Ta2O12: 12.946(3) Å). AC impedance results show that both the strontium and barium members exhibit mainly a bulk contribution with a rather small grain‐boundary contribution. The ionic conductivity increases with increasing ionic radius of the alkaline earth elements. The barium compound, Li6BaLa2Ta2O12, shows the highest ionic conductivity, 4.0×10–5 S cm–1 at 22 °C with an activation energy of 0.40 eV, which is comparable to other lithium ion conductors, especially with the presently employed solid electrolyte lithium phosphorus oxynitride (Lipon) for all‐solid‐state lithium ion batteries. DC electrical measurements using lithium‐ion‐blocking and reversible electrodes revealed that the electronic conductivity is very small, and a high electrochemical stability (&&num;62; 6 V/Li) was exhibited at room temperature. Interestingly, Li6ALa2Ta2O12 was found to be chemically stable with molten metallic lithium.
Improving the Brightness and Daylight Contrast of Organic Light‐Emitting Diodes
Authors: Vaenkatesan V. , Wegh R. T. , Teunissen J.‐P. , Lub J. , Bastiaansen C. W. M. , Broer D. J. 
Published: January 2005

AbstractFor most applications of displays based on organic light‐emitting diodes (LEDs), it is desirable to have good daylight contrast in combination with a high intensity of emitted light. The conventional approaches to enhance the daylight contrast, using a black cathode or circular polarizers, result in a significant loss of light emitted by the LED. A rather novel approach to enhance daylight contrast while keeping loss of emitted light to a minimum is the introduction of a chiral‐nematic film in the device. This approach leads to an increase in light efficiency by a factor of 1.8 (with respect to circular polarizers) with some loss in daylight contrast values within the reflection band of the chiral‐nematic film. Outside the reflection band, however, the contrast approaches infinity.
Influence of Side‐Chain Structure and Irradiation Condition on Photoalignment of Ladder‐Like Polysiloxane Films
Authors: Gu H.‐W. , Xie P. , Fu P.‐F. , Zhang T.‐Y. , Zhang R.‐B. 
Published: January 2005

AbstractIn this paper we consider the photo‐induced aligning capability of various ladder‐like polysiloxane‐based photoalignment films—which could be used in liquid‐crystal displays—bearing different photoreactive side chains, i.e., laterally grafted cinnamate/azobenzene‐based dual photoreactive side chains with a short or longer spacer, and terminally fixed coumarin‐containing side chains. Results from polarized optical microscopy (POM), Fourier‐transform infrared (FTIR) spectroscopy, surface‐enhanced Raman scattering (SERS), atomic force microscopy (AFM), etc., are integrated to elucidate the influence of side‐chain structure and the irradiation conditions on the photoalignment of ladder‐like polysiloxane films. It is demonstrated that the film containing the dual photoreactive group with a longer spacer exhibits better alignment properties. Reasonably, the concerted photoreactions of the dual photoreactive group and the longer spacer are beneficial to the cooperative motion of chromophores at the “domain level”, resulting in improved alignment facility and stability. The complicated effects of irradiation conditions and moderate annealing are also discussed. High‐quality alignment of the polysilsesquioxane (LPS)‐based photoalignment film LPS‐CA11 with a longer spacer between the LPS main chain and cinnamoyl/azobenzene side chains can be achieved only within an optimal range of exposure (5–8 J cm–2), while the pretilt angles can be adjusted in the range 0.5°–7° by varying the incident light intensity. Additionally, moderate annealing before and after illumination can markedly improve the alignment uniformity by self‐healing of defects.
Preparation of Hollow Silica Nanospheres by Surface‐Initiated Atom Transfer Radical Polymerization on Polymer Latex Templates
Authors: Chen Y. , Kang E. T. , Neoh K. G. , Greiner A. 
Published: January 2005

AbstractPoly(vinylbenzyl chloride), (PVBC) latex particles of about 100 nm in size are prepared by emulsion polymerization. Silyl functional groups are introduced onto the PVBC‐nanoparticle templates via surface‐initiated atom transfer radical polymerization of 3‐(trimethoxysilyl)propyl methacrylate. The silyl groups are then converted into a silica shell, approximately 20 nm thick, via a reaction with tetraethoxysilane in ethanolic ammonia. Hollow silica nanospheres are finally generated by thermal decomposition of the PVBC template cores. Field‐emission scanning electron microscopy and field‐emission transmission electron microscopy are used to characterize the intermediate products and the hollow nanospheres. Fourier‐transform infrared spectroscopy results indicate that the polymer cores are completely decomposed.
Formation of Oxynitride as the Photocatalytic Enhancing Site in Nitrogen‐Doped Titania Nanocatalysts: Comparison to a Commercial Nanopowder
Authors: Chen X. , Lou Y.‐B. , Samia A. C. S. , Burda C. , Gole J. L. 
Published: January 2005

AbstractA nitrogen‐doped TiO2 nanocolloid has been successfully prepared and its properties compared with the commercially available TiO2 nanomaterial, Degussa P25. Several characterization techniques, X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), transmission electron spectroscopy (TEM), Fourier transform infrared (FT‐IR) spectroscopy, Raman scattering, and UV‐visible reflectance spectra, are combined in order to determine the crystal phase and grain size, shape, degree of nitrogen incorporation, and nature of the resultant oxynitride chemical bonding on the surface and in the bulk. The high relative photocatalytic activity of the nitrogen doped‐TiO2 nanocolloid is evaluated through a study of the decomposition of methylene blue under visible light excitation. The ease and degree of substitutional‐insertional nitrogen doping is held accountable for the significant increase in photocatalytic activity in the porous nanocolloid versus the nitrided commercial nanopowder. It is suggested that the nitrogen incorporation produces an NO bonding region as evidenced by the resulting XPS spectrum.
Permeability of subcritical hydrocarbons in activated carbon
Authors: Bae Jun‐Seok , Do D. D. 
Published: January 2005

AbstractA new diffusion and flow model is presented to describe the behavior of hydrocarbon vapors in activated carbon. The micro/mesopore size distribution (PSD) is obtained according to Do's method which consists of two sequential processes of pore layering and pore filling. This model uses the micro/meso PSD obtained from each adsorbate equilibrium isotherm, which reflects the dynamics behavior of adsorbing molecules through the solid. The initial rise in total permeability is mainly attributed to adsorbed‐phase diffusion (that is, surface diffusion), whereas the decrease over reduced pressure of about 0.9 is attributed to the reduction of pore space available for gas phase diffusion and flow. A functional form of surface diffusivity is proposed and validated with experimental data. This model predicts well the permeability of condensable hydrocarbon vapors in activated carbon. © 2005 American Institute of Chemical Engineers AIChE J, 51: 487–501, 2005
Personality traits as intermediary phenotypes in suicidal behavior: Genetic issues
Authors: Baud Patrick 
Published: January 2005

AbstractA genetic contribution to the risk of suicidal behavior is now supported by many studies. It probably involves specific factors acting on their own, independently of the genetic transmission of associated psychiatric disorders. A history of childhood maltreatment, adverse events, psychosocial stress, psychological traits and major psychiatric disorders all appear to contribute to the global risk of suicide attempt or completion. The interplay between previously identified risk factors, different as they are in nature and degree of complexity, still remains to be clarified. A stress‐diathesis model has been proposed, where trait‐like genetic and developmental risk factors (the diathesis) interact through still unknown mechanisms with actual (stress‐related) factors to create the conditions for a suicidal gesture. Disentangling the effects of these risk factors, and specifically the effects of the genetic factors influencing these different pathological conditions, appears to be a difficult task. Indeed the results of candidate gene association studies suggest that genetic vulnerability factors for various related psychiatric phenotypes (major psychiatric disorders and personality traits) partly overlap with more specific factors predisposing to suicidal behavior. Personality traits are partly under genetic control and may be closer to the genetic effects than psychiatric syndromes. We review here the available data on the genetics of personality traits presumably involved in suicidal behavior, focusing on the association studies carried out with serotonin‐related genes. We suggest that future studies on the genetic vulnerability to suicidal behavior should include the investigation of endophenotypes, with the aim of deciphering the mechanisms underlying the genetic susceptibility to these closely associated phenotypes. © 2005 Wiley‐Liss, Inc.
Improvement of the polarity of polyethylene with oxidized Fischer–Tropsch paraffin wax and its influence on the final mechanical properties
Authors: Novák I. , Krupa I. , Luyt A. S. 
Published: January 2005

AbstractThe easy, low‐cost modification of the polarity of low‐density polyethylene (LDPE) and high‐density polyethylene (HDPE) through blending with oxidized Fischer–Tropsch wax was investigated. A 10 wt % concentration of the wax increased the polar component of the total surface free energy 10 times for LDPE and 4.5 times for HDPE. Modified LDPE also had significantly higher adhesion to the polar substrate, which was represented by a crosslinked epoxy‐based resin. This behavior was not observed for HDPE. The conservation of the good mechanical properties of polyethylene was observed. The wax content had only a moderate influence on the mechanical properties. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1164–1168, 2005
Structure and properties of phenolic resin/nanoclay composites synthesized by in situ polymerization
Authors: Pappas Jonathan , Patel Kandarp , Nauman E. B. 
Published: January 2005

AbstractAn in situ semibatch polymerization process for making phenolic resin/montmorillonite clay nanocomposites is developed. It is found that auxiliary mixing in phenol allows intercalation of the monomer and polymer between montmorillonite clay layers. At 2.7% clay by mass the montmorillonite is predominantly exfoliated (fully dispersed). At higher clay loading, a substantial amount of the clay remains in aggregate or intercalated form. When the montmorillonite is exfoliated, the material is mechanically superior. The composite has a tensile modulus that is 21% higher than the neat resin and has 87% improved fracture strength, 100% larger fracture energy, and strain to failure 13% above the pure resin. Thermogravimetric analysis shows the montmorillonite system maintains its thermal stability up to 200°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1169–1174, 2005
Propylene–ethylene random copolymers: Comonomer effects on crystallinity and application properties
Authors: Gahleitner Markus , Jääskeläinen Pirjo , Ratajski Ewa , Paulik Christian , Reussner Jens , Wolfschwenger Johannes , Neißl Wolfgang 
Published: January 2005

AbstractFor understanding the correlation chain from the polymer structure to the final application properties of propylene–ethylene random copolymers, four commercial grades with different ethylene content (0–8 mol %) but identical molecular weight distributions were investigated. Structural investigations concerning the comonomer distribution, using two different techniques (temperature rising elution fractionation and stepwise isothermal segregation), showed an increase of inhomogeneity with the total comonomer content, which was reflected for temperature rising elution fractionation in a widening of the elution temperature range. Crystallinity and crystallization speed studies confirmed the reduced overall crystallinity and increase of γ‐modification content as reported previously, but they also showed the reason for these effects in the distinctive decrease of the spherulitic growth speed. Good correlations of all these parameters to the mechanical performance of the four materials were obtained. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1073–1081, 2005