bluuebunny/crossref_metadata_2025_split huggingface dataset:
NO2and children’s respiratory symptoms in the PATY study
Authors: Pattenden S , Hoek G , Braun-Fahrländer C , Forastiere F , Kosheleva A , Neuberger M , Fletcher T 
Published: November 2006

Objectives:NO2is a major urban air pollutant. Previously reported associations between ambient NO2and children’s respiratory health have been inconsistent, and independent effects of correlated pollutants hard to assess. The authors examined effects of NO2on a spectrum of 11 respiratory symptoms, controlling for PM10and SO2, using a large pooled dataset.Methods:Cross sectional studies were conducted in Russia, Austria, Italy, Switzerland, and the Netherlands, during 1993–99, contributing in total 23 955 children. Study-specific odds ratios for associations with ambient NO2are estimated using logistic regressions with area-level random effects. Heterogeneity between study-specific results, and mean estimates (allowing for heterogeneity) are calculated.Results:Long term average NO2concentrations were unrelated to prevalences of bronchitis or asthma. Associations were found for sensitivity to inhaled allergens and allergy to pets, with mean odds ratios around 1.14 per 10 μg/m3NO2. SO2had little confounding effect, but an initial association between NO2and morning cough was reduced after controlling for PM10.Associations with reported allergy were not reduced by adjustment for the other pollutants. Odds ratios for allergic symptoms tended to be higher for the 9–12 year old children compared with the 6–8 year old children.Conclusions:Evidence for associations between NO2and respiratory symptoms was robust only for inhalation allergies. NO2most likely is acting as an indicator of traffic related air pollutants, though its direct effect cannot be ruled out. This remains important, as policies to reduce traffic related air pollution will not result in rapid reductions.
First Principles Calculation for Cu Gettering by Dopantor Dopant-Vacancy Complex in Silicon Crystal
Authors: Sueoka Koji , Ohara Shigehiro , Shiba Seiji , Fukutani Seishiro 
Published: November 2006

For finding the effective gettering center of cupper (Cu) atom in silicon (Si) crystal, an interaction between interstitial Cu atom and dopant (B, Sb, As, P), C or O atom was studied with first principles calculation. It was found that only B could be an effective gettering center. This result indicates that heavily B doped p/p+ epitaxial wafers will show a sufficient gettering efficiency for Cu contamination.	In order to design the gettering center of Cu in n/n+ epitaxial wafers, the interaction between vanancy (V)-Sb, V-As or V-P complexes and Cu was investigated. It was found that these complexes could be effective gettering centers. The mechanism of Cu gettering by oxide precipitates was also studied with further calculations. It was found that the stabilities of Cu atom in β-crystobalite or in strained Si were not superior to that in strain-free Si. The trapping at the interface or the interaction with emitted interstitial Si (I) from oxide precipitates should be the possible mechanisms for Cu gettering.
Frequency Changes Observed with the EQCM Resulting from Hydrophilic/Hydrophobic Transitions
Authors: Woods R. , Jeffrey Matthew I. 
Published: November 2006

The processes responsible for the altered frequency response of the EQCM when the electrode surface changes from a hydrophilic to a hydrophobic condition have been investigated using silver electrodes in ethyl xanthate solution.	The frequency accurately tracks the voltammetric charge when silver ethyl xanthate is formed, but moves in the opposite direction when xanthate is chemisorbed; chemisorption is known to result in the surface becoming hydrophobic. The characteristics of the EQCM in a xanthate solution that had been completely degassed was the same as that in one deaerated with nitrogen. This is inconsistent with nanobubbles being formed at a hydrophobic surface, but is in agreement with slippage occurring as a result of a change in water structure. Similar voltammograms were observed for smooth silver surfaces to those for electrodeposited ones, but the alteration in frequency response during the change in wettability was much greater. This is also explained in terms of water structure.
Gold Enhanced Observation of Surface Products in Chalcopyrite Dissolution
Authors: Hope Gregory A. , Parker Gretel , Woods R. 
Published: November 2006

Gold decoration of chalcopyrite surfaces has been shown to stimulate surface enhancement of Raman scattering and this enables sulfur oxidation products to be investigated when they are undetectable by normal Raman spectroscopy.	Solution cementation, sputtering and evaporative deposition of gold each facilitated SERS. The last of these techniques was selected for studies of chalcopyrite leaching since it has the least possibility of affecting the mineral surface. Similar oxidation products and electrochemical behaviour were observed on potential cycling of chalcopyrite electrodes in H2SO4 and HCl. SERS spectroscopy indicated that S-S bonding was present in the major product, indicative of sulfur in a somewhat amorphous structure. It is proposed that this species results from aging of a metal-deficient remnant sulfide lattice formed when metal atoms are dissolved. Ex situ investigations of the oxidation of chalcopyrite substantiated the conclusion that the species detected after gold deposition were oxidation products of chalcopyrite.
A Rotating Disk Electrochemical Dual Autoclave for the Study of Electrochemistry and Leaching at High Temperature and Pressure
Authors: Lazaro Isabel , Jeffrey Matthew I. 
Published: November 2006

A study of the pressure acid leaching of chalcopyrite was performed using a unique rotating disc electrochemical dual autoclave. The autoclave permits electrochemical and leaching experiments to be conducted up to 200 {degree sign}C using a chalcopyrite rotating disk electrode. The paper describes in detail the design of the dual autoclave, which consists of separate pre- heater and reactor. This eliminates heat-up effects, and allows either leaching or electrochemistry to be commenced at the correct temperature. The mixed potential measurements and voltammograms of chalcopyrite at 150 {degree sign}C indicate that pressure acid leaching in a solution containing 0.1 M Fe(III) will occur quite rapidly. In comparison, when using 120 psi partial pressure of oxygen, the mixed potential is in the so- called	prewave region, and hence slow leaching would be expected.
PVT Growth at High Temperatures
Authors: Singh Narsingh B. , Wagner Brian , Sherwin Marc , Berghmans Andre , Thomson Darren , Kahler David , Knuteson David 
Published: November 2006

Physical vapor transport (PVT) growth method was used to grow bulk crystals of AlN and thick epitaxial SiC films on on-axis Si-face 4H-SiC(0001) substrates from the powder source materials. Both bulk and thick film crystals were characterized by scanning electron microscopy (SEM), which showed a surface morphology did not have any observable growth defects or cracking. We observed nice hexagonal growth morphology a typical characteristic of diffusion-limited growth. River-patterns free from micro bubbles and micro voids were observed on the as grown surface.	An XRD rocking curve measured the FWHM as 51.0 arc seconds and a reciprocal space map showed a singular intense region that is attributed to the high quality homoepitaxial SiC film. A similar value was observed for small AlN crystals also.
The Present Status and Recent Advancements in Corona-Kelvin Non-Contact Electrical Metrology of Dielectrics for IC-Manufacturing
Authors: Wilson Marshall , Marinskiy Dmitriy , Byelyayev Anton , D'Amico John , Findlay Andrew , Jastrzebski Lubek , Lagowski Jacek 
Published: November 2006

Non-contact electrical metrology offers a fast and cost saving monitoring of dielectrics in IC manufacturing process.	This corona-Kelvin measuring technique has entered the maturity stage with about 400 tools installed in silicon IC-fabs. We discuss recent advancements that broaden the spectrum of monitoring parameters and enhance the precision of these measurements. We also discuss the current ongoing extension of corona-Kelvin metrology to the micro scale measurement on sites as small as 30µm x 30µm. This opens new possibilities for non-contact electrical testing of product wafers, rather than expensive process monitor wafers. Micro-measurement is illustrated using flash memory ONO structures and corona induced programming and erasing.
Advanced Metal Gate Electrode Options Compatible with ALD and AVD® HfSiOx-Based Gate Dielectrics
Authors: Karim Zia , Biossiere Olivier , Lohe Christoph , Zhang Zhihong , Park Woong , Manke Christian , Baumann Peter K. , Dalton Jeremie , Ramanathan Sasangan , Lindner Johannes , Seidel Tom , Lehnen Peer 
Published: November 2006

We have investigated metal gate electrodes for use with high k HfSiOx gate dielectric films using AVD® and ALD technology. First, we report on the characterization of the AVD® and ALD deposition techniques where both HfO2 and SiO2 are combined for the formation of HfSiOx. Nitrogen is then incorporated using both in-situ and ex-situ methods to form HfSiON and the resulting film properties are compared. Using an AVD process a work-function of >4.7eV for Ru and RuO2 gate electrode metals in combination with HfSiOx was obtained. A TaN-based metal gate was also characterized to target a promising pMOS solution using different compositions.	Together with its high flexibility and composition control, both ALD and AVD® can become key processes for advanced high-k dielectrics as well as compatible CMOS metal electrodes.
Mechanical Stress and Defect Formation in Device Processing
Authors: Polignano Maria Luisa , Carnevale Gianpietro , Fantini Paolo , Mica Isabella 
Published: November 2006

In this work we address the problem of estimating the mechanical stress and the related risk of crystal defect generation in a complex device process. The validity of numerical calculations of the mechanical stress developed in the device process flow is assessed by comparing the simulation results with the electrical measurements of test structures designed to monitor the dislocations formation and of other silicon strain sensitive structures. The results show that based upon numerical calculations	it is possible to define	mechanical stress criteria for preventing defect generation. By using this sort of criteria, potentially dangerous process variations can be easily identified. This method is quite general and can be applied to any device process flow. On the other hand, by comparing the electrical results of structures prone to defect generation and of stress-sensitive transistors with a non-critical geometry for defect generation, it is shown that after defect nucleation the elastic stress in non-critical structures and the defect- related failure fraction in critical structures may evolve into opposite directions. Therefore, suitable stress criteria are needed at all the levels in the process flow where crystal damage may cause defect nucleation. In this study it is also pointed out that a high temperature stress release annealing can be beneficial for stress reduction and defect prevention, but its position in the process flow is critical.
Evaluation of Silicon Photovoltaic Devices with Near-Field Scanning Optical Microscopy
Authors: Wagener Magnus C. , Rozgonyi George 
Published: November 2006

This report presents the use of near field scanning optical microscopy (NSOM) as a complementary tool for photovoltaic investigations requiring a significantly higher degree of spatial resolution and sensitivity. The applicability of near-field photocurrent contrast imaging to cast silicon material and nano-crystalline silicon thin-film is demonstrated. The recombination efficiency of individual dislocation arrays was resolved and revealed secondary bands of reduced collection efficiency adjacent to each dislocation array.	The collection uniformity of a nano-crystalline silicon thin film was also successfully imaged.
Regular Dislocation Networks in Silicon as a Tool for Novel Device Application
Authors: Kittler Martin , Reiche Manfred , Seifert Winfried , Yu X. , Arguirov T. , Vyvenko Oleg , Mchedlidze Teimuraz , Wilhelm Thomas 
Published: November 2006

The paper deals with possibilities of utilizing dislocation structures as active components of devices. The suggested means for controlled formation of dislocations is direct wafer bonding, giving rise to well defined dislocation networks with adjustable properties.	It is shown that the networks allow building light emitting diodes based on the D line luminescence of the dislocations. A light emitter at about 1.5 mm wavelength is demonstrated, with an efficiency potential estimated at 1%. Immobilization of biomolecules on Si surfaces by Coulomb interaction with the dislocations in the network is another application discussed. Finally, the potential use of dislocation networks as insulating layers permeable to impurities to be gettered and as three-dimensional buried conductive channels in the Si wafer is addressed.
New Silicon-Based Materials for Spintronics Applications - Si:V and Si:Cr
Authors: Misiuk Andrzej , Chow Lee , Barcz Adam , Surma Barbara , Bak-Misiuk Jadwiga , Romanowski P. 
Published: November 2006

We present here two new silicon-based materials for possible applications as spintronics materials.	These materials are based on high dose ion implantation of transition metal ions, V+ or Cr+ into a single crystalline silicon wafer. After ion implantation, thermal anneals at high temperatures and high hydrostatic pressures are carried out in a high pressure chamber. Secondary ion mass spectrometry is used to characterize the re-distribution of the implanted atoms after thermal anneals; photoluminescence and X-ray techniques are applied to check microstructure of the samples. A variable temperature SQUID magnetometer is used to measure the magnetic properties of the processed samples. It is found that some of the samples showed ferromagnetic hysteresis loops at low temperatures. Implications of our findings are discussed in terms of future applications of spintronics materials based on ion-implanted silicon.
Study of Charged States of Si Quantum Dots with Ge Core
Authors: Makihara Katsunori , Ikeda Mitsuhisa , Higashi Seiichiro , Miyazaki Seiichi 
Published: November 2006

Si quantum dots with Ge core were self-assembled on thermally- grown SiO2 from thermal decomposition of alternately pure SiH4 and GeH4 diluted with He. Changes in the surface potential caused by electron charging to and discharging from individual Si dot with and without Ge core were studied by using a Kelvin probe technique in atomic force microscopy (AFM). The potential change attributable to the extraction of one electron from a Si dot with Ge core was observed after tapping an AFM tip biased at +1.2V while for pure Si dot with almost the same size, the tip bias required for causing a similar potential change was as high as +3.0V.	Also there was no significant difference in tip bias for electron injection between Si dot with and without Ge core. The result suggests an energy band structure in which Ge core act as a deep potential well for holes but less modulate the conduction band.	Correspondingly, stable positively-charged states for Si dots with Ge core were confirmed in comparison with pure Si dots.
Silicon-Germanium Saturable Absorber Mirrors for Ultra-Short Pulse Generation
Authors: Kaertner Franz X. , Byun Hyunil , Grawert Felix , Gopinath Juliet , Shen Hanfei , Ippen Erich , Akiyama Shoji , Liu Jifeng , Wada Kazumi , Kimerling Lionel, K 
Published: November 2006

Silicon-Germanium saturable absorber mirrors are developed for laser mode locking. The fabrication process is fashioned such that a highly reflecting Si/SiO2 Bragg mirror with a crystalline absorber top-layer is generated. One step of wafer- bonding allows for subsequent epitaxial growth on the mirror. A six-pair reflector centered at 1400 nm with 99.8% peak reflectivity, a 99%-reflectivity bandwidth of 700 nm and a surface roughness of 0.136 nm is demonstrated.	A thin Germanium layer is epitaxially deposited on the mirror surface to provide saturable absorption at 1550nm. with a sub- picosecond recovery time. The device is used to achieve stable, continuously modelocked operation of an Er-Yb:glass laser centered at 1540 nm, generating 220 fs pulses.
XAFS Study of Heat-Treated Cobalt Tetraphenylporphyrin Supported on Active Carbon
Authors: Hiroshima Kazutaka , Nonaka Takamasa , Asaoka Takahiko , Morimoto Yu 
Published: November 2006

Co K-edge XANES measurements were conducted for heat-treated cobalt tetraphenylporphyrins supported on activated carbon (CoTPP/C) which was under use as the cathode electrode of a PEFC to investigate the effect of applied potential on the local structure and the electronic property of cobalt of CoTPP/Cs. N K-edge NEXAFS measurements of CoTPP/Cs	were also conducted to examine the effect of heat treatment temperature on the local structure around the nitrogen atoms. As a result, the structure of the cobalt atom surrounded by the nitrogen atoms (Co-N4 structure) was preserved during the fuel cell operation when the heat treatment temperature was 600{degree sign}C. The preservation of the Co-N4 structure is likely the reason for the highest catalytic activity for oxygen reduction reaction of this catalyst.
Effective Testing Matrix for Studying Membrane Durability in PEM Fuel Cells: Part I. Chemical Durability
Authors: Liu Wen , Crum Matt 
Published: November 2006

In order to advance membrane technologies for PEM fuel cells, it is critical to establish an effective testing matrix, which includes tests that target specific mechanisms of chemical and mechanical durability, as well as tests that can challenge the membrane with combined failure mechanisms. Furthermore, the tests should be both accelerated and realistic. In studies of membrane chemical durability, it was discovered that using regular test cells resulted in highly non-uniform membrane degradation in the active area. This compromised the quantitative value of the data and prevented the use of average fluoride release rate over the entire cell as an accurate measure of the chemical degradation rate of the membrane. Therefore, a homogeneous environment was needed for more quantitative studies of membrane chemical durability. Among various options, operation at OCV using standard test cells and operation under a load using high gas stoichiometries with a uniform test cell were chosen.	Test results indicate that combinations of these test protocols enable the dependable selection of more chemically durable membranes and also provide quantitative data to assist understanding of degradation mechanisms in fuel cells under various operation conditions.
Increased Stability of PFSA Proton Exchange Membranes Under Fuel Cell Operation by the Decomposition of Peroxide Catalyzed by Heteropoly Acids.
Authors: Herring Andrew M. , Gregory Haugen M. , Fanqin Meng , Aieta Niccolo V. , Horan James L. , Frey Mathew H. , Hamrock Steven J. , Kuo Mei Chen 
Published: November 2006

Proton exchange membranes were cast from mixtures of the 3M perfluorinated sulfonic acid ionomer, with side chain -O-(CF2) 4-SO3H, and various heteropoly acids (HPAs) at a 10 or 20 wt% doping level.	The membrane electrode assemblies (MEAs) prepared from these membranes were subjected to a fuel cell testing protocols involving incubation to steady state, temperature challenge, accelerated testing, and post mortem analysis. The cell temperature was varied from 70 - 100 ºC under relatively dry conditions, 70 ºC dewpoint, to avoid leaching of the HPA. The most important finding from this study was that the more stable HPAs, H4SiW12O40, α-H3P2W18O62, and H6P2W21O71 reduce the rate of F- release threefold and improve the performance of the MEA dramatically under these conditions. For HPAs that possibly rearrange in peroxide or at elevated temperatures, H3PW12O40, H6CoW12O40, H5SiAlW11O39, H6As2W21O69, and H21B3W39O162, the results were mixed as fragments of these molecules possibly interfere with the fuel cell electrochemistry.
Free Convection Direct Methanol Fuel Cells Powered by Electroosmotic Pumps
Authors: Buie Cullen , Kim Daejoong , Litster Shawn , Santiago Juan G. G. 
Published: November 2006

This work reports on the design and performance evaluation of a miniature direct methanol fuel cell (DMFC) integrated with an electroosmotic pump for methanol delivery. Electroosmotic pumps require minimal parasitic power while boasting no moving parts and simple fuel cell integration. Here, electroosmotic pumps are realized from commercially available porous glass frits.	Experimental results show that electroosmotic pumps deliver 4M, and 8M methanol/water mixtures to DMFCs (at 50oC) while utilizing 1% and 4% of the fuel cells power, respectively. Furthermore, we discuss pertinent design considerations when using electroosmotic pumps with DMFCs and areas of future study.
Palladium-Platinum Alloy Anode Catalysts for Direct Formic Acid Fuel Cells
Authors: Blair Sharon , Lycke Derek , Iordache Coca A. 
Published: November 2006

The relationship between the composition of palladium-platinum alloy nanoparticles and their performance as electrocatalysts for formic acid electro-oxidation has been studied. Unsupported nanoparticle palladium-platinum alloys have been prepared by the co-reduction of palladium and platinum salts with ethylene glycol and characterized by X-ray diffraction (XRD).	The electrocatalytic activities of the alloys were compared to that of pure platinum and palladium nanoparticle catalysts using cyclic voltammetry, chronopotentiometry, and chronoamperometry. The results reveal a synergetic effect of platinum and palladium as well as independent behaviour of the two metals for formic acid oxidation.
Ab Initio Investigations of Textured Ni2Si Films on Silicon
Authors: Alippi Paola , Alberti Alessandra 
Published: November 2006

Transition metal silicides grown on Si substrates show peculiar structural behavior, due to their rich variety of phases with different stoichiometric compositions.	Phases with low electrical resistivity and high thermal stability are needed as contact materials in advanced integrated circuits while nickel silicide is the main candidate as future material for interconnects. Recently, structural investigations on thin silicide films on Si(100) have characterized novel forms of silicide texturing: alignment of planes across the interface seems to be preferred over standard in-plane epitaxial alignment. We investigate by first-principle total energy calculations the role of interface and elastic energies in the stabilization of textured silicide film structures on Si(001). From the comparison of calculated interface energy values we address the role of energetics in texture selection.
Effect of Deposition Temperature on Chemical Structure of Lanthanum Oxide/Si Interface Structure
Authors: Nohira Hiroshi , Matsuda Toru , Tachi Kiichi , Shiino Yasuhiro , Song Jaeyeol , Kuroki Yusuke , Ng Jin Aun , Ahmet Parhat , Kakushima Kuniyuki , Tsutsui Kazuo , Ikenaga Eiji , Kobayashi Keisuke , Iwai H. , Hattori Takeo 
Published: November 2006

The effect of substrate-temperature during the deposition of lanthanum oxide on the chemical structure of lanthanum oxide/Si(100) interfacial transition layer formed between lanthanum oxide and Si-substrate was studied from the measurements of angle-resolved Si 1s, O 1s and La 3d5/2 photoelectron spectra.	In the case of the deposition at room temperature the amount of lanthanum silicate (La-silicate) was extremely small, and was not affected by the post deposition annealing (PDA) at 300{degree sign}C, and increased by PDA at temperature above 500{degree sign}C. On the other hand, in the case of the deposition at 300{degree sign}C the amount of La-silicate increased appreciably by PDA even at 300{degree sign}C. Therefore, the existence of La-silicate accelerates the formation of La-silicate by PDA.