Synthesis of Y3Al5O12:Eu2+ Phosphor by a Facile Hydrogen Iodide‐AssistedSol–Gel Method

Pure yttrium aluminum garnet (YAG) phosphor doped with Eu²⁺ has been successfully synthesized by a facile sol–gel method. The use of hydrogen iodide aimed to get Eu²⁺ ions, confirmed by X‐ray absorption near‐edge structure (XANES) analysis. Nearly spherical and well dispersed particles were synthesized. The produced YAG:Eu²⁺ phosphor powder had a broad emission band in the range of 400–600 nm with a peak at 480 nm, attributed to the allowed 4f⁷–4f⁶5d¹ transition of electrons in Eu²⁺ ions. The proposed method could also be expanded to prepare many other Eu²⁺‐doped phosphors with a solution method.     

Influence of fuel type,dilution and equivalence ratio on the emission reduction from the auto-ignition in an Homogeneous Charge Compression Ignition engine

One technology that seems to be promising for automobile pollution reduction is the Homogeneous Charge Compression Ignition (HCCI). This technology still faces auto-ignition and emission-control problems. This paper focuses on the emission problem, since it is incumbent to realize engines that pollute less. For this purpose, this paper presents results concerning the measurement of the emissions of CO, NO_x, CO₂, O₂ and hydrocarbons. HCCI conditions are used, with equivalence ratios between 0.26 and 0.54, inlet temperatures of 70 °C and 120 °C and compression ratios of 10.2 and 13.5, with different fuel types: gasoline, gasoline surrogate, diesel, diesel surrogate and mixtures of n-heptane/toluene. The effect of dilution is considered for gasoline, while the effect of the equivalence ratio is considered for all the fuels. No significant amount of NO_x has been measured. It appeared that the CO, O₂ and hydrocarbon emissions were reduced by decreasing the toluene content of the fuel and by decreasing the dilution. The opposite holds for CO₂. The reduction of the hydrocarbon emission appears to compete with the reduction of the CO₂ emission. Diesel seemed to produce less CO and hydrocarbons than gasoline when auto-ignited. An example of emission reduction control is presented in this paper.     

Combustion oxidization synthesis of unique cage-like nanotetrapod ZnO and its optical property

Cage-like nano-tetrapod ZnO is a novel structure, which was successfully synthesized by combustion oxidation at 850 degrees C. No catalyst or carrier gases were used. Thorough SEM and TEM analyses revealed that the linking legs of the tetrapod ZnO can have or not interface. The formation or not of an interface is discussed and it was attributed to different growth process of the cage-like ZnO nano-tetrapod. Enhanced UV emission peak at the wavelength of 375 nm, featuring high intensity and narrow width, indicates a highly crystalline structure. A green emission, recorded at 502 nm, was related to the defects of the surface of the branching configuration as well as to the ZnO nuclei of the cage-like nano-tetrapod ZnO.     

The magnetic susceptibilities of CsMnCl3·2H2O and CsMnCl3·2D2O

The magnetic susceptibilities of CsMnCl₃·2H₂O and CsMnCl₃·2D₂O have been measured at temperatures between 0.35 and 35 K. Above 9 K both salts show the broad susceptibility maximum of the one-dimensional Heisenberg antiferromagnet previously seen in the hydrate. In both cases the intrachain exchange parameter isJ/k=–3.00 K. AtT _N (4.89 K for the hydrate) three-dimensional antiferromagnetic long-range order begins to develop due to weak interchain interactions with preferred alignment along theb axis. AtT _N all susceptibility-temperature curves have their maximum slopes, those of _a and _c being negative. This is shown to be related to the unusual phase diagram of these systems. The limiting behavior of the susceptibilities asT 0 K is established and interpreted. (0) reflects the strong anisotropy of the spinwave spectrum due to the dominant intrachain interaction.Supported in part by the National Science Foundation and the Office of Naval Research.Supported in part by the Science Research Fund of the Ministry of Education of the Japanese government.     

Evidence that cholesteryl ester hydrolase and triglyceride lipase are different enzymes in rat liver

Studies on intracellular cholesteryl ester hydrolase (CEH) and triglyceride lipase (TGL) from rat adipose tissue and adrenal cortex have suggested that a single protein is responsible for both activities. To determine whether one hepatic protein catalyzes both reactions, we studied several properties of CEH and TGL in rat liver. During liver perfusion with heparin, perfusate peaks of TGL and CEH did not consistently coincide, and TGL activity was considerably higher and less heat-stable than that of CEH. Significant TGL, but not CEH, activity was released during incubation of isolated hepatocytes. Although microsomes isolated from hepatocytes contained both activities, the specific activities of CEH and TGL in cytosol from hepatocytes were 95% and 3%, respectively, of those found in cytosol from whole liver. Preincubation of liver cytosol with 5 mM Mg²⁺ decreased CEH, but not TGL, activity. Intracellular CEH and TGL activities were completely separated by prep-disc gel electrophoresis. Finally, both cytosolic and microsomal TGL, but not CEH, activities were inhibited by antiserum against rat hepatic TGL. We conclude that extracellular TGL does not have CEH activity and intracellular CEH differs from TGL.     

Extending Stochastic and Quantum Functions

Abstract. We determine a large class of recognizable functions properly containing stochastic and quantum functions, having good closure properties and where a cutpoint theorem is valid.     

Opening new dimensions for e-Tourism

In this paper we describe an e-Tourism environment that takes a community-driven approach to foster a lively society of travelers who exchange travel experiences, recommend tourism destinations or just listen to catch some interesting gossip. Moreover, business transactions such as booking a trip or getting assistance from travel advisors or community members are constituent parts of this environment. All these happen in an integrated, game-like e-Business application where each e-Tourist is impersonated as an avatar. More precisely, we apply 3D Electronic Institutions, a framework developed and employed in the area of multi-agent systems, to the tourism domain. The system interface is realized by means of a 3D game engine that provides sophisticated 3D visualization and enables humans to interact with the environment. We present “itchy feet”, a prototype implementing this 3D e-Tourism environment to showcase first visual impressions. This new environment is a perfect research playground for examining heterogeneous societies comprising humans and software agents, and their relationship in e-Tourism.     

An experimental and numerical investigation on the influence of external gas recirculation on the HCCI autoignition process in an engine: Thermal, diluting, and chemical effects

In order to contribute to the solution of controlling the autoignition in a homogeneous charge compression ignition (HCCI) engine, parameters linked to external gas recirculation (EGR) seem to be of particular interest. Experiments performed with EGR present some difficulties in interpreting results using only the diluting and thermal aspect of EGR. Lately, the chemical aspect of EGR is taken more into consideration, because this aspect causes a complex interaction with the dilution and thermal aspects of EGR. This paper studies the influence of EGR on the autoignition process and particularly the chemical aspect of EGR. The diluents present in EGR are simulated by N₂ and CO₂, with dilution factors going from 0 to 46 vol%. For the chemically active species that could be present in EGR, the species CO, NO, and CH₂O are used. The initial concentration in the inlet mixture of CO and NO is varied between 0 and 170 ppm, while that of CH₂O alters between 0 and 1400 ppm. For the investigation of the effect of the chemical species on the autoignition, a fixed dilution factor of 23 vol% and a fixed EGR temperature of 70 °C are maintained. The inlet temperature is held at 70 °C, the equivalence ratios between 0.29 and 0.41, and the compression ratio at 10.2. The fuels used for the autoignition are n-heptane and PRF40. It appeared that CO, in the investigated domain, did not influence the ignition delays, while NO had two different effects. At concentrations up until 45 ppm, NO advanced the ignition delays for the PRF40 and at higher concentrations, the ignition delayed. The influence of NO on the autoignition of n-heptane seemed to be insignificant, probably due to the higher burn rate of n-heptane. CH₂O seemed to delay the ignition. The results suggested that especially the formation of OH radicals or their consumption by the chemical additives determines how the reactivity of the autoignition changed.     

Lipid composition of the sponge Verongia aerophoba from the Canary Islands

The fatty acid composition of the lipids from the sponge Verongia aerophoba was investigated and 60 acids were identified. Two of them were new and their structures were elucidated by gas chromatography‐mass spectrometry. These acids were identified as 20‐methylhexacosanoic and Δ5, 9, 22‐nonacosatrienoic. Only 13 sterols were present, and aplysterol predominated. In the volatile fraction 13 compounds were identified, mainly fatty acids, their esters and hydrocarbons, while in the n‐butanol fraction we found mainly free fatty acids and free amino acids.