End-tidal carbon dioxide monitoring using a naso-buccal sensor is not appropriate to monitor capnia during non-invasive ventilation.

BACKGROUND: In acute respiratory failure, arterial blood gas analysis (ABG) is used to diagnose hypercapnia. Once non-invasive ventilation (NIV) is initiated, ABG should at least be repeated within 1��h to assess PaCO2 response to treatment in order to help detect NIV failure. The main aim of this study was to assess whether measuring end-tidal CO2 (EtCO2) with a dedicated naso-buccal sensor during NIV could predict PaCO2 variation and/or PaCO2 absolute values. The additional aim was to assess whether active or passive prolonged expiratory maneuvers could improve the agreement between expiratory CO2 and PaCO2. METHODS: This is a prospective study in adult patients suffering from acute hypercapnic respiratory failure (PaCO2 ≥ 45��mmHg) treated with NIV. EtCO2 and expiratory CO2 values during active and passive expiratory maneuvers were measured using a dedicated naso-buccal sensor and compared to concomitant PaCO2 values. The agreement between two consecutive values of EtCO2 (delta EtCO2) and two consecutive values of PaCO2 (delta PaCO2) and between PaCO2 and concomitant expiratory CO2 values was assessed using the Bland and Altman method adjusted for the effects of repeated measurements. RESULTS: Fifty-four datasets from a population of 11 patients (8 COPD and 3 non-COPD patients), were included in the analysis. PaCO2 values ranged from 39 to 80��mmHg, and EtCO2 from 12 to 68��mmHg. In the observed agreement between delta EtCO2 and deltaPaCO2, bias was -0.3��mmHg, and limits of agreement were -17.8 and 17.2��mmHg. In agreement between PaCO2 and EtCO2, bias was 14.7��mmHg, and limits of agreement were -6.6 and 36.1��mmHg. Adding active and passive expiration maneuvers did not improve PaCO2 prediction. CONCLUSIONS: During NIV delivered for acute hypercapnic respiratory failure, measuring EtCO2 using a dedicating naso-buccal sensor was inaccurate to predict both PaCO2 and PaCO2 variations over time. Active and passive expiration maneuvers did not improve PaCO2 prediction. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01489150.

Current transport and electroluminescence mechanisms in thin SiO2 films containing Si nanocluster-sensitized erbium ions.

We have studied the current transport and electroluminescence properties of metal oxide semiconductor MOS devices in which the oxide layer, which is codoped with silicon nanoclusters and erbium ions, is made by magnetron sputtering. Electrical measurements have allowed us to identify a Poole-Frenkel conduction mechanism. We observe an important contribution of the Si nanoclusters to the conduction in silicon oxide films, and no evidence of Fowler-Nordheim tunneling. The results suggest that the electroluminescence of the erbium ions in these layers is generated by energy transfer from the Si nanoparticles. Finally, we report an electroluminescence power efficiency above 10���3%. �� 2009 American Institute of Physics. doi:10.1063/1.3213386

Electron tunneling in heavily In-doped polycrystalline CdS films

The electrical properties of heavily In���doped polycrystalline CdS films have been studied as a function of the doping level. The films were prepared by vacuum coevaporation of CdS and In. Conductivity and Hall measurements were performed over the temperature range 77-400 K. The conductivity decreases weakly with the temperature and shows a tendency towards saturation at low temperatures. A simple relationship ��=��0(1+��T2) is found in the low���temperature range. The temperature dependence of the mobility is similar to that of the conductivity since the Hall coefficient is found to be a constant in the whole temperature range. We interpret the experimental results in terms of a modified version of grain���boundary trapping Seto"s model, taking into account thermionic emission and tunneling of carriers through the potential barriers. The barriers are found to be high and narrow, and tunneling becomes the predominating transport mechanism.

Properties of amorphous silicon thin films grown in square wave modulated silane rf discharges.

Hydrogenated amorphous silicon (a���Si:H) thin films have been obtained from pure SiH4 rf discharges by using the square wave modulation (SQWM) method. Film properties have been studied by means of spectroellipsometry, thermal desorption spectrometry, photothermal deflection spectroscopy and electrical conductivity measurements, as a function of the modulation frequency of the rf power amplitude (0.2-4000 Hz). The films deposited at frequencies about 1 kHz show the best structural and optoelectronic characteristics. Based upon the experimental results, a qualitative model is presented, which points up the importance of plasma negative ions in the deposition of a���Si:H from SQWM rf discharges through their influence on powder particle formation.

Highly textured Sr, Nb, co-doped BiFeO3 thin films grown on SrRuO3/Si substrates by rf-sputtering

In this study, (011)-highly oriented Sr, Nb co-doped BiFeO3 (BFO) thin films were successfully grown on SrRuO3/Si substrates by rf-magnetron sputtering. The presence of parasite magnetic phases was ruled out based on the high resolution x-ray diffraction data. BFO films exhibited a columnar-like grain growth with rms surface roughness values of 5.3 nm and average grain sizes of 65-70 nm for samples with different thicknesses. Remanent polarization values (2Pr) of 54 lC cm 2 at room temperature were found for the BFO films with a ferroelectric behavior characteristic of an asymmetric device structure. Analysis of the leakage mechanisms for this structure in negative bias suggests Schottky injection and a dominant Poole-Frenkel trap-limited conduction at room temperature. Oxygen vacancies and Fe3��/Fe2�� trap centers are consistent with the surface chemical bonding states analysis from x-ray photoelectron spectroscopy data. The (011)-BFO/ SrRuO3/Si film structure exhibits a strong magnetic interaction at the interface between the multiferroic film and the substrate layer where an enhanced ferromagnetic response at 5 K was observed. Zero-field cooled (ZFC) and field cooled (FC) magnetization curves of this film system revealed a possible spin glass behavior at spin freezing temperatures below 30 K depending on the BFO film thickness.

Resistance Switching in Transparent Magnetic MgO Films

We have studied the abrupt and hysteretic changes of resistance in MgO-based capacitor devices. The switching behavior is discussed in terms of the formation and rupture of conduction filaments due to the migration of structural defects in the electric field, together with the redox events which affects the mobile carriers. The results presented in this paper suggest that MgO transparent films combining ferromagnetism and multilevel switching characteristics might pave the way for a new method for spintronic multibit data storage.

Separation of ammonia and carbon dioxide by adsorption

T��ss�� ty��ss�� on tutkittu ammoniakin ja hiilidioksidin erottamista adsorptio prosessilla ja suunniteltiin paineen muunteluun perustuvan adsorptioprosessin (PSA) k��ytt����. Ty��n tarkoituksena oli laskea adsorptioon perustuvan prosessin kannattavuus melamiinitehtaan poistokaasujen erotuksessa. T��t�� varten ty��ss�� suunniteltiin tehdasmitta-kaavainen prosessi ja arvioitiin sen kannattavuus. Ty��ss�� mitattiin adsorptiotasapainot, joiden perusteella sovitettiin sopiva kokeellinen adsorptioisotermi. Adsorptioisotermi lis��ttiin simulointiohjelmaan, jonka avulla suunniteltiin kaksi vaihtoehtoista pilot laitteistoa kaasujen erottamiseksi. Toisella pilot laitteistolla saadaan mitattua vain l��p��isyk��yr��t, mutta paremmalla versiolla saadaan my��s tietoa erotettujen komponenttien puhtaudesta. Suunnittelun t��rkeimpi�� l��ht��kohtia on molempien komponenttien mahdollisimman korkea puhtaus ja talteenottoaste. T��ysimittakaavainen tehdas suunniteltiin simulointiohjelmiston avulla kahdelle eri kapasiteetille ja arvioitiin niiden kustannukset ja kannattavuus. Adsorptioprosessit osoittautuivat kannattaviksi kaasuseoksen erottamisessa kummassakin tapauksessa

Painatuksen UV-stabiilisuuden optimointi fenolihartsatussa paperissa

T��ss�� diplomity��ss�� tutkittiin painetun paperin ja siit�� fenoliformaldehydihartsilla impregnoimalla valmistetun pinnoituskalvon UV-stabiilisuuden parantamis-mahdollisuuksia. Ty��n kirjallisuusosassa k��sitell����n painetun pinnoituskalvon valmistusprosessia ja painatuksen UV-valonkestoon vaikuttavia tekij��it��. Painov��rin pigmentti, sen m����r�� ja k��sittely, painov��rin sideaine sek�� fenoliformaldehydihartsi ja sen lis��aineet vaikuttavat pinnoitetun betonoimisvanerin s����nkesto-ominaisuuksiin. Erilaisilla ep��orgaanisilla valkoisilla pigmenteill�� ja kidemuodoilla on erilainen UV-valonkesto ja taitekerroin. P����llyst��m��ll�� titaanidioksidi esimerkiksi alumiini- tai zirkoniumoksideilla sen UV-valonkestoa voidaan parantaa merkitt��v��sti. UV-hajoaminen voidaan havaita painetun pinnoitteen liituuntumisena. Liituuntumista voidaan pit���� veden ja hapen v��lisen�� reaktiona, jota titaanidioksidi ja UV-s��teily katalysoivat. Sen takia my��s muiden valkoisten ep��orgaanisten pigmenttien ominaisuuksia ja k��ytt���� selvitettiin. Kokeissa k��ytettiin yhdeks���� eri painov��ri��, kahta eri paksuista paperia ja kahta eri tyyppist�� hartsia. Painov��rej�� ohennettiin vedell�� ja paperin painopuolta vaihdeltiin. Kaikissa painatuksissa k��ytettiin kolmea eri rasterointiasteen laattaa, jolloin painov��rin m����r���� paperissa saatiin v��hennetty��. Painetuista papereista mitattiin densiteetti, v��rim����r��, pisara-absorptio vedell�� ja kontaktikulma hartsilla. My��s painov��rin tunkeumaa selvitettiin paperin poikkileikeist�� tehtyjen SEM-kuvien avulla. Painetut paperit impregnoitiin fenoliformaldehydihartsilla kalvoksi. Pinnoituskalvot puristettiin vanerin pinnalle laboratoriopuristimella. Koekappaleet altistettiin UV-valolle, sateelle ja pakkaselle s����kaapissa 400 h ajan, mik�� vastaa noin 1,5 vuotta ulkona Suomen oloissa. Kappaleista mitattiin kiilto, v��rinmuutos ja liituuntuminen. Pinnoitteen liituuntumista tapahtui v��hiten niiss�� koepisteiss��, joissa painatus oli tehty 30 % rasteroidulla laatallaS����nkest��v�� TiO2 osoittautui hyv��ksi, mutta my��s ZnO-pigmentill�� saatiin hyvi�� tuloksia. ZnO-koepisteess�� liituuntumisreaktio ei ole niin voimakkaasti katalysoitu kuin TiO2-koepisteiss��. Paksun paperin painatuspuolella n��ytti olevan merkityst�� s����nkestoon. Huopapuolelle painettuna pinnoitteen liituuntuminen oli v��h��isemp����

Surface passivation of crystalline silicon by Cat-CVD amorphous and nanocrystalline thin silicon films

In this work, we study the electronic surface passivation of crystalline silicon with intrinsic thin silicon films deposited by Catalytic CVD. The contactless method used to determine the effective surface recombination velocity was the quasi-steady-state photoconductance technique. Hydrogenated amorphous and nanocrystalline silicon films were evaluated as passivating layers on n- and p-type float zone silicon wafers. The best results were obtained with amorphous silicon films, which allowed effective surface recombination velocities as low as 60 and 130 cms -1 on p- and n-type silicon, respectively. To our knowledge, these are the best results ever reported with intrinsic amorphous silicon films deposited by Catalytic CVD. The passivating properties of nanocrystalline silicon films strongly depended on the deposition conditions, especially on the filament temperature. Samples grown at lower filament temperatures (1600 ��C) allowed effective surface recombination velocities of 450 and 600 cms -1 on n- and p-type silicon.

Cationic and charge segregation in La2/3Ca1/3MnO3 thin films grown on (001) and (110) SrTiO3.

Electron energy-loss spectroscopy is used to map composition and electronic states in epitaxial La2/3Ca1/3MnO3 films grown on SrTiO3 001 and 110 substrates. It is found that in partially relaxed 110 films cationic composition and valence state of Mn3+/4+ ions are preserved across the film thickness. In contrast, in fully strained 001 films, the Ca/La ratio gradually changes across the film, being La rich at film/substrate interface and La depleted at free surface; Mn valence state changes accordingly. These observations suggest that a strongly orientation-dependent adaptative composition mechanism dominates stress accommodation in manganite films and provides microscopic understanding of their dissimilar magnetic properties.

Top-gate microcrystalline silicon TFTs processed at low temperature (<200��C)

N-type as well P-type top-gate microcrystalline silicon thin film transistors (TFTs) are fabricated on glass substrates at a maximum temperature of 200 ��C. The active layer is an undoped ��c-Si film, 200 nm thick, deposited by Hot-Wire Chemical Vapor. The drain and source regions are highly phosphorus (N-type TFTs) or boron (P-type TFTs)-doped ��c-films deposited by HW-CVD. The gate insulator is a silicon dioxide film deposited by RF sputtering. Al-SiO 2-N type c-Si structures using this insulator present low flat-band voltage,-0.2 V, and low density of states at the interface D it=6.4��10 10 eV -1 cm -2. High field effect mobility, 25 cm 2/V s for electrons and 1.1 cm 2/V s for holes, is obtained. These values are very high, particularly the hole mobility that was never reached previously.

Domain matched epitaxial growth of Bi1.5Zn1Nb1.5O7 thin films by pulsed laser deposition

Bi1.5Zn1Nb1.5O7 (BZN) epitaxial thin films were grown by pulsed laser deposition on Al2O3 with a double ZnO buffer layer through domain matching epitaxy (DME) mechanism. The pole figure analysis and reciprocal space mapping revealed the single crystalline nature of the thin film. The pole figure analysis also shows a 60�� twinning for the (222) oriented crystals. Sharp intense spots in the SAED pattern also indicate the high crystalline nature of BZN thin film. The Fourier filtered HRTEM images of the BZN-ZnO interface confirms the domain matched epitaxy of BZN with ZnO buffer. An electric field dependent dielectric tunability of 68% was obtained for the BZN thin films with inter digital capacitors patterned over the film.

New features of the layer-by-layer deposition of microcrystalline silicon films revealed by spectroscopic ellipsometry and high resolution transmission electron microscopy

Spectroscopic ellipsometry and high resolution transmission electron microscopy have been used to characterize microcrystalline silicon films. We obtain an excellent agreement between the multilayer model used in the analysis of the optical data and the microscopy measurements. Moreover, thanks to the high resolution achieved in the microscopy measurements and to the improved optical models, two new features of the layer-by-layer deposition of microcrystalline silicon have been detected: i) the microcrystalline films present large crystals extending from the a-Si:H substrate to the film surface, despite the sequential process in the layer-by-layer deposition; and ii) a porous layer exists between the amorphous silicon substrate and the microcrystalline silicon film.

The Electronic Structure of Co-Sputtered Zinc Indium Tin Oxide Thin Films

Zinc indium tin oxide (ZITO) transparent conductive oxide layers were deposited via radio frequency (RF) magnetron co-sputtering at room temperature. A series of samples with gradually varying zinc content was investigated. The samples were characterized with x-ray and ultraviolet photoemission spectroscopy (XPS, UPS) to determine the electronic structure of the surface. Valence and conduction bands maxima (VBM, CBM), and work function were determined. The experiments indicate that increasing Zn content results in films with a higher defect rate at the surface leading to the formation of a degenerately doped surface layer if the Zn content surpasses 50%. Furthermore, the experiments demonstrate that ZITO is susceptible to ultraviolet light induced work function reduction, similar to what was earlier observed on ITO and TiO2 films.