Μm Si Research Articles

Temporal variability and bioavailability of iron and other nutrients during the spring phytoplankton bloom in the Oyashio region

Abstract Iron [dissolved Fe (D-Fe) and total dissolvable Fe (T-Fe)] and nutrient concentrations in the surface water of the Oyashio region (northwestern North Pacific) were measured before and during spring phytoplankton bloom (March to May in 2007). During the pre-bloom period (middle of March), we observed vertically uniform concentrations of iron (0.3–0.5 nM [D-Fe] and 3–5 nM [T-Fe]), macronutrients (10–15 μM NO3+NO2, 1.0–1.5 μM PO4 and 20–30 μM Si(OH)4) and chlorophyll a (Chl-a, 0.3–0.4 μg l−1) throughout the upper 125 to 150 m due to vertical mixing during winter. Water temperature and salinity before the bloom were also vertically uniform with >5 °C and S>33.5, the conditions of a modified Kuroshio warm-water (MKW) ring, higher than those of the Coastal Oyashio Water (COW). The cold COW (

Stable silicon isotope analysis on nanomole quantities using MC-ICP-MS with a hexapole gas-collision cell

We demonstrate in this study that a single focusing multiple collector inductively coupled plasma mass spectrometer (MC-ICP-MS) equipped with a hexapole gas-collision cell (GV-instrument®Isoprobe) can precisely determine the δ29Si (2S.D., 0.2‰) using a total Si consumption of less than 14 nmole (390 ng Si). Testing and evaluation of background, rinse time, and major matrix effects have been performed in a systematic way to establish a procedure to measure δ29Si in small quantities. Chemical purification prior to analysis is required to remove potential interferences. For data collected during a four-year period, the average δ29Si value of IRMM-018 relative to NBS-28 was found to be −0.95‰ (n = 23, 2S.D. 0.16‰) with a 95% confidence interval (−0.95 ± 0.028‰). The mean δ29Si value of the Big-Batch standard was found to be −5.50‰ (n = 6, 2S.D. 0.26‰). Although determination of the δ30Si measurements is not possible, with our current instrument we demonstrate that this system provides a fast and long-term reliable method for the analysis of δ29Si in purified samples with low Si concentration (18 µM Si).

On the anomalous silicate emission features of active galactic nuclei: a possible interpretation based on porous dust

Abstract The recent Spitzer detections of the 9.7 μm Si–O silicate emission in type 1 active galactic nuclei (AGN) provide support for the AGN unification scheme. The properties of the silicate dust are of key importance to understand the physical, chemical and evolutionary properties of the obscuring dusty torus around the AGN. Compared to that of the Galactic interstellar medium (ISM), the 10 μm silicate emission profile of type 1 AGN is broadened and has a clear shift of peak position to longer wavelengths. In literature, this is generally interpreted as an indication of the deviations of the silicate composition, size and degree of crystallization of the AGN from that of the Galactic ISM. In this Letter, we show that the observed peak shift and profile broadening of the 9.7 μm silicate emission feature can be explained in terms of porous composite dust consisting of ordinary interstellar amorphous silicate, amorphous carbon and vacuum. Porous dust is naturally expected in the dense circumnuclear region around the AGN, as a consequence of grain coagulation.

Diffusional creep induced stress relaxation in thin Cu films on silicon

The results of stress measurements during annealing of thin copper films deposited on 100 μm Si substrates are presented. The stress in thin films was determined by using an optical system for curvature measurements. The annealing experiments were done during thermal cycles of heating and cooling procedures from room temperature up to 400 °C with a rate 10 °C/min. The total thickness of thin films was between 20 and 100 nm. The obtained results showed that the difference between the end and the initial values of the ratio of force to width increases with the thickness of the samples. The initial linear shape of the temperature–stress plots reaches higher temperature values with an increase in film thickness. In order to explain the observations, the dependence of stress on temperature was calculated using the rate of Coble creep. It was found that the theoretical curves reveal the same features as the experimental data. It was concluded that diffusional creep mechanism dominates for thin film of thickness below 100 nm.

Silicon light emitting diodes emitting over the 1.2–1.4μm wavelength region in the extended optical communication band

Here, we demonstrate bulk silicon light emitting diodes operating over the 1.2–1.35μm range. This is achieved by the implantation of the rare earth thulium, incorporated in the trivalent Tm3+ state, into silicon p-n junctions. Light emitting diodes operating under forward bias have been obtained by codoping of boron to reduce the thermal quenching. Seven sharp lines are observed, corresponding to known internal Tm3+ transitions in the manifold from the H53 to the H63 ground states. This center, together with the basic 1.15μm silicon emitters and Si:Er devices operating at 1.54μm, now enables significant coverage of the extended (1.1–1.8μm) optical communications band in silicon.

Passivation of InSb surface for manufacturing infrared devices

We studied the reduction of active surface states at the InSb/insulator interface by the reduction of hysteresis in C– V plots and by the performance of InSb diodes operated in photovoltaic mode. The InSb wafers were cleaned with CP4A etchant (HNO 3:CH 3COOH:HF:H 2O at 2:1:1:10). Then layers of 0.4 μm SiO 2, 0.4 μm Si 3N 4 and 0.5 μm Si 3N 4/SiO 2 were deposited on the cleaned surfaced by plasma enhanced chemical vapor deposition (PECVD). After measuring the surface morphology by atomic force microscopy (AFM) the atomic percentage of each element in each compound (e.g. Si and O 2 in SiO 2 layer) was studied by energy-dispersive X-ray spectroscopy (EDX). By using photoemission spectroscopy (XPS), we showed that the SiO 2, Si 3N 4 and Si 3N 4/SiO 2 layers include Sb and/or SbO x and the Sb In antisite during deposition occurred and for this reason their etch rates differ from pure SiO 2, Si 3N 4 and Si 3N 4/SiO 2 layers. Then the gold metal was deposited on the samples and capacitance voltage measurement was made on the MIS samples. The results showed hysteresis free curves if the surface has been cleaned correctly. Finally by depositing the 0.4 μm SiO 2, 0.4 μm Si 3N 4 and 0.5 μm Si 3N 4/SiO 2 on diode structure of InSb, the performance of diode in this case was compared with the anodic oxidation method. The results showed the performance of device is better than for the anodic oxidation method.

Factors affecting phosphate adsorption to aluminum in lake water: Implications for lake restoration

Treatment of lake inlets or lake sediments with aluminum (Al) is being increasingly used for lake restoration but only few studies exist concerning competitive substances that might influence phosphate (PO 4 3−) removal from lake water. Therefore, chemical interferences of several ions (magnesium, silicate, chloride and humic acid) on PO 4 3− adsorption to Al(OH) 3 were studied. Interference of each ion was studied in artificial lake water, and the complex interactions occurring in natural water were studied in water from 30 Danish lakes at pH 7 in both cases. In the artificial lake water Al:P ratio was high as sediment P-pools were the targets while in the natural lake water Al addition was generally lower as only P present in the water was targeted (i.e. inlet water). The single-ion experiments evidenced that silicate (> 200 μM) and humic acids significantly decreased the effectiveness of PO 4 3− adsorption to Al(OH) 3 by 10–13% at 450 μM Si and 17% at 1 mM C, respectively. NaCl did not influence adsorption of PO 4 3− to Al(OH) 3, however, PO 4 3− removal was slightly reduced in seawater, mainly due to the presence of Mg 2+. The studies on interferences in natural lake water showed that as long as the PO 4 3− concentration was low (< 5 μM), silicate competed with PO 4 3− for adsorption sites on Al(OH) 3 but at higher PO 4 3− concentrations, color and DOC (as indicators of HA) were the main variables decreasing PO 4 3− removal from lake water. Inhibition of PO 4 3− precipitation in natural lake water appeared complex and did not allow for a simple calculation of Al dose from the concentration of potentially competitive ions. Recommendation for lake management is therefore still that precipitation assays should be carried out for any type of inlet or lake water prior to Al application.

Photosensitiser-loaded biodegradable polymeric micelles: Preparation, characterisation and in vitro PDT efficacy

The application of photosensitisers (PSs) in photodynamic therapy (PDT) is often hampered by their hydrophobicity, as this complicates their formulation and results in an unfavourable biodistribution. Consequently, there is an urgent need for novel delivery vehicles for PSs. In this paper, the loading and stability of thermosensitive mPEG- b-p(HPMAm-Lac 2) micelles with a hydrophobic solketal-substituted phthalocyanine (Si(sol) 2Pc) photosensitiser were studied. It was shown that the Si(sol) 2Pc could be loaded efficiently in the micelles (diameter 75 nm) up to a concentration of ∼ 2 mg/mL. UV/Vis and fluorescence spectroscopy showed that at low concentrations (≤ 0.05 μM, 0.45 mg/mL polymer), the PS was molecularly dissolved in the micellar core, whereas it was present in an aggregated form at higher concentrations. In B16F10 and 14C cells, the photocytotoxicity of Si(sol) 2Pc-loaded micelles (PS < 0.05 μM) was similar to free PS, i.e. IC 50 of 3.0 ± 0.2 nM (10% serum). The cellular uptake of high-loaded micelles (10 μM Si(sol) 2Pc) was low and independent of the serum concentration. The nanoaggregates of Si(sol) 2Pc loaded in the micellar core were only released upon hydrolysis-induced micellar dissociation, which was observed after 5.5 h at pH 8.7 at 37 °C. The stability of the high-loaded micellar Si(sol) 2Pc formulation also in the presence of serum, the controlled release of the PS upon micellar disintegration and the high photodynamic activity of Si(sol) 2Pc make these micelles interesting for future in vivo studies.

The Irish Sea: Is it eutrophic?

The question of whether the Irish Sea is eutrophic is addressed by reviewing the evidence for anthropogenic nutrient enrichment, elevated phytoplankton production and biomass and undesirable disturbance in the context of the EU and OSPAR definitions of eutrophication. Winter concentrations of dissolved available inorganic phosphate (DAIP), nitrogen (DAIN as nitrate and nitrite) and silicate (Si) in coastal waters and concentrations of DAIP and Si in offshore waters of the Irish Sea are elevated relative to winter Celtic Sea shelf break concentrations (0.5 μM DAIP, 7.7 μM DAIN and 2.7 μM Si). Significant, negative nutrient salinity relationships and analysis of the Isle of Man nutrient time-series indicate that the elevated Irish Sea levels of DAIP and DAIN are the result of anthropogenic enrichment with highest concentrations (≈2.0 μM DAIP, 30 μM DAIN and 17 μM Si) measured in near shore eastern Irish Sea waters. Summer levels of phytoplankton chlorophyll (Chl) range from <0.1 to 11.4 mg m −3 (mean: 3.4 mg m −3) and from <0.1 to 16.4 mg m −3 (mean: 2.2 mg m −3) in coastal and offshore waters of the western Irish Sea, respectively. Offshore eastern Irish Sea summer chlorophyll levels range from 0.3 to 3.8 mg m −3 (mean: 1.8 mg m −3). Higher levels of spring (up to 43.9 mg m −3) and summer (up to 22.7 mg m −3) biomass in Liverpool Bay are attributed to nutrient enrichment. Estimates of spring and summer production in different regions of the Irish Sea are ≤194 g C m −2. The absence of: (a) oxygen depletion in near shore and open waters of the Irish Sea (except the seasonally isolated western Irish Sea bottom water); (b) trends in the frequency of Phaeocystis spp. blooms and occurrence of toxin producing algae; and (c) changes in the dominant life form of pelagic primary producers, point to a lack of undesirable disturbance and hence argue against anthropogenic eutrophication in the Irish Sea. This conclusion is discussed in the context of future trends in anthropogenic nutrient inputs.

Identification of Novel Autoxidation Products of the ω-3 Fatty Acid Eicosapentaenoic Acid in Vitro and in Vivo

Increased intake of fish oil rich in the omega-3 fatty acids eicosapentaenoic acid (EPA, C20:5 omega-3) and docosahexaenoic acid (DHA, C22:6 omega-3) reduces the incidence of human disorders such as atherosclerotic cardiovascular disease. However, mechanisms that contribute to the beneficial effects of fish oil consumption are poorly understood. Mounting evidence suggests that oxidation products of EPA and DHA may be responsible, at least in part, for these benefits. Previously, we have defined the free radical-induced oxidation of arachidonic acid in vitro and in vivo and have proposed a unified mechanism for its peroxidation. We hypothesize that the oxidation of EPA can be rationally defined but would be predicted to be significantly more complex than arachidonate because of the fact that EPA contains an addition carbon-carbon double bond. Herein, we present, for the first time, a unified mechanism for the peroxidation of EPA. Novel oxidation products were identified employing state-of-the-art mass spectrometric techniques including Ag(+) coordination ionspray and atmospheric pressure chemical ionization mass spectrometry. Predicted compounds detected both in vitro and in vivo included monocylic peroxides, serial cyclic peroxides, bicyclic endoperoxides, and dioxolane-endoperoxides. Systematic study of the peroxidation of EPA provides the basis to examine the role of specific oxidation products as mediators of the biological effects of fish oil.

In situ HCl etching of Si for the elaboration of locally misorientated surfaces

We have studied the in situ HCl etching of Si active areas on patterned wafers. After some in situ HCl etching at 20 Torr of Si(1 0 0), we have locally obtained 2 μm long areas with misorientation angles around 4.5° towards 〈1 1 0〉. Furthermore, we have evidenced a recess shape transition from convex ( T ≤ 865 °C) to concave ( T ≥ 895 °C) as the etch temperature increases, with a nearly flat surface with no facets at T = 880 °C. The morphology of the etched structures at a given time, temperature and P HCl / P H 2 ratio will be a function of the slope lengths and the pattern dimensions. Different kinds of surfaces (rounded areas, facets) were obtained in 3.5 μm × 3.5 μm Si windows after HCl etching at 850 °C during 300 s, depending on the stress within. Thermal oxidations can indeed be used to increase by 65 MPa up to 110 MPa the compressive stress in those Si windows which are bordered by SiO 2 shallow trench isolation. An increase of the misorientation angle from 4.5° up to 6° occurred after the above-mentioned HCl etch when switching from conventional to highly strained Si windows. For the shortest etching times studied here (150 s), a selective etching of 3.5 μm × 3.5 μm Si windows edges is responsible for the misorientation. The etch is then more uniform. Stress gradients might consequently be one of the main misorientation causes. We have also probed the influence of the shallow trench isolation (STI) thickness on the misorientation. A morphological difference before HCl etching has been shown to be responsible for the transition from sloped to rounded areas. A local loading effect may prevail in this case.

Cold Temperature Preparation of XTEM Specimens of Embedded Metallic Nanoparticles

Abstract Nanoparticles (1-10 nm in diameter) are particularly susceptible to disorder, amorphization, deformation and/or dissolution upon ion irradiation as compared to their bulk counterparts, which is a consequence of the enhanced surface area to volume ratio of the former (structural disorder is often observed to be preferentially located at the surface). Synchrotron-radiation-based analytical techniques are ideally suited for the elucidation of structural perturbations as compared to the bulk material. Such techniques are commonly complemented by cross-sectional transmission electron microscopy (XTEM). XTEM offers invaluable information with respect to shape and morphology of the nanoparticles. For the present work, Cu nanoparticles were synthesized within a 2 μm amorphous SiO2 matrix on a 520 μm Si support by ion implantation and thermal annealing following a procedure described elsewhere. In order to study the influence that ion irradiation has on the nanoparticles, the sample was then irradiated with 1x1015 ions / cm2 high-energy (5 MeV) Sn+ ions.

Medipix2: Processing and measurements of GaAs pixel detectors

For applications with high-energy X-ray photons (30–120 keV) semiconductors with high Z like CdTe and GaAs are required. In comparison with silicon detectors, the absorption of GaAs is higher. GaAs wafers had been prepared and flip-chip bonded to the Medipix2 readout chip at the Freiburger Materialforschungszentrum (FMF) using a low-temperature process. For this work, 300-μm-thick wafers were chosen for first measurements. The pixel and backside contacts were processed with Ti–Pt–Au to form Schottky contacts. The surface of the samples was passivated with BCB. The pixel pitch was 55 μm (standard Medipix) and 110 μm. The performance of these GaAs detectors was studied for different radiation sources and X-ray tubes. The efficiency of the GaAs assemblies is compared to 700-μm-thick Si assemblies. The number of detected quanta in 300 μm GaAs is 10 times higher than in 700 μm Si for γ-rays at 44 and 60 keV. This can be explained by the higher absorption of the GaAs.

Effects of turbulence on TEP dynamics under contrasting nutrient conditions: implications for aggregation and sedimentation processes

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 323:47-57 (2006) - doi:10.3354/meps323047 Effects of turbulence on TEP dynamics under contrasting nutrient conditions: implications for aggregation and sedimentation processes S. Beauvais1, M. L. Pedrotti1,*, J. Egge2, K. Iversen2, C. Marrasé3 1Marine Microbial Ecology Group, Laboratoire d’Océanographie de Villefranche, Univ. Paris VI, CNRS UMR 7093, Observatoire Océanologique de Villefranche-sur-Mer, Station Zoologique, BP 28, 06234 Villefranche-sur-Mer, France 2Department of Fisheries and Marine Biology, University of Bergen, HIB, 5020 Bergen, Norway 3Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, (CSIC) Passeig Maritim de la Barceloneta, Barcelona, Spain *Corresponding author. Email: pedrotti@obs-vlfr.fr ABSTRACT: The effect of different small-scale turbulence intensities on transparent exopolymeric particle (TEP) dynamics was studied in natural North Sea coastal waters. The abundance, volume, size spectra and carbon content of TEP were examined in mesocosms with and without added nutrients: no addition (T series) and a Redfield ratio supply on Day 1 (NT series), fertilized with 16 µM N:1 µM P:32 µM Si to favor phytoplankton production in the form of a bloom. Turbulence was generated by vertically oscillating grids, operating continuously for 14 d. We determined whether TEP production, under contrasting nutrient conditions, changes with level of turbulence. TEP concentration increased with turbulence. The effect of turbulence was likely indirect, by inducing an increase in growth rates of diatoms that actively exude TEP precursor, particularly when nutrients were exhausted. Following TEP production, the ratio of particulate organic carbon to nitrogen increased after the bloom, regardless of turbulence level. TEP formation led to a decoupling of carbon and nitrogen dynamics, with a large flow of carbon channeled into the TEP pool, representing up to 44% of the primary production, and was constant with the turbulence intensity. While turbulence had no effect on small particles (<40 µm), turbulence favored the aggregation of TEP >40 µm. We found significant sedimentation of TEP when turbulence was lower (5 to 8 × 10–2 cm2 s–3) and a persistence of the TEP pool in the tanks without sinking at higher levels of turbulence intensity, typical of storm events (ε = 1 cm2 s–3). KEY WORDS: Transparent exopolymer particles · TEP production · Phytoplankton · POC · Turbulence · Nutrients · Aggregation · Mesocosms Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 323. Online publication date: October 05, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research.

Quasi-Continuous Elution Chromatographic Purification of a Steroid Active Compound

In our present paper the elaborated quasi-continuous elution chromatographic separation is shown using the following instrument set up and experimental conditions: a KNAUER CSEP 9116 laboratory-scale SMB unit with five KNAUER K-501 HPLC pumps and eight columns (column dimension: 250X16 mm I.D.). The columns were packed in our laboratory by dry-packing method using vibration, the applied packing material was UETIKON C-490 15-35 μm Si gel. The appropriate eluent was methylene chloride/ethyl acetate mixture and as back-flushing solvent, pure ethyl acetate was used. After the elaboration of quasi-continuous elution chromatographic purification, the intensification of the process was carried out. The specific capacity parameters of the best quasi-continuous experiments were compared with the performance parameters of the current batch pilot-scale separation of the compound.

Enhancement of Ferroelectricity and Magnetoelectric Effect of BiFeO3 Thin Films on Membrane Structure

ABSTRACTMultiferroic BiFeO3 thin films have been prepared on Pt/TiO2/SiO2/thick (200 μm) and membrane (15 μm) Si substrate by pulsed laser deposition (PLD) to confirm the influence of stress from substrate. Si membrane was obtained by etching using reactive ion etching (RIE) until thickness is to be 15 μm. The X-ray diffraction peaks of BiFeO3 thin film on Pt/TiO2/SiO2/Si (15 μm) membrane substrate slightly shift to lower angles, compared to those on Pt/TiO2/SiO2/Si (200 μm) substrate. Ferroelectric hysteresis loops were also measured at 150 K before and after Si etching by RIE. The BiFeO3 thin film on the Pt/TiO2/SiO2/Si (15 μm) membrane structure shows remanent polarization (Pr) of 95 μC/cm2 for a maximum applied voltage of 18 V, which is larger than Pr = 71 μC/cm2 of BiFeO3 thin film on Pt/TiO2/SiO2/Si (200 μm) substrate at the same measurement conditions. Under magnetic field of 1.1 T, remanent polarization (Pr) of BiFeO3 thin film on Pt/TiO2/SiO2/Si (15 μm) membrane structure increased from 95 μC/cm2 to 101 μC/cm2 at 150 K due to stress relaxation of BiFeO3 thin film.

Seasonal dynamics of inorganic nutrients and phytoplankton biomass in the NW Alboran Sea

The seasonal dynamics of inorganic nutrients and phytoplankton biomass (chlorophyll a), and its relation with hydrological features, was studied in the NW Alboran Sea during four cruises conducted in February, April, July and October 2002. In the upper layers, the seasonal pattern of nutrient concentrations and their molar ratios (N:Si:P) was greatly influenced by hydrological conditions. The higher nutrient concentrations were observed during the spring cruise (2.54 μM NO 3 −, 0.21 μM PO 4 3− and 1.55 μM Si(OH) 4, on average), coinciding with the increase of salinity due to upwelling induced by westerlies. The lowest nutrient concentrations were observed during summer (<0.54 μM NO 3 −, 0.13 μM PO 4 3− and 0.75 μM Si(OH) 4, on average), when the lower salinities were detected. Nutrient molar ratios (N:Si:P) followed the same seasonal pattern as nutrient distribution. During all the cruises, the ratio N:P in the top 20 m was lower than 16:1, indicating a NO 3 − deficiency relative to PO 4 3−. The N:P ratio increased with depth, reaching values higher than 16:1 in the deeper layers (200–300 m). The N:Si ratio in the top 20 m was lower than 1:1, excepting during spring when N:Si ratios higher than 1:1 were observed in some stations due to the upwelling event. The N:Si ratio increased with depth, showing a maximum at 50–100 m (>1.5:1), which indicates a shift towards Si-deficiency in these layers. The Si:P ratio was much lower than 16:1 throughout the water column during the four cruises. In general, the spatial and seasonal variation of phytoplankton biomass showed a strong coupling with hydrological and chemical fields. The higher chlorophyll a concentrations at the depth of the chlorophyll maximum were found in April (2.57 mg m −3 on average), while the lowest phytoplankton biomass corresponded to the winter cruise (0.74 mg m −3 on average). The low nitrate concentrations together with the low N:P ratios found in the upper layers (top 20 m) during the winter, summer and autumn cruises suggest that N-limitation could occur in these layers during great part of the year. However, N-limitation during the spring cruise was temporally overcome by nutrient enrichment caused by an intense wind-driven upwelling event.

Reducing AC Power Consumption by Three-Dimensional Integration of Ge-On-Insulator CMOS on 1-Poly-6-Metal 0.18 μm Si MOSFETs

We have used three-dimensional (3D) integration to reduce the ac power consumption in interconnects, which is the most severe issue beyond the dc power arising from the gate dielectric leakage current. From a direct calculation of the ac power consumption using an electromagnetic method, we show that both the ac power consumption and maximum operation frequency can be improved by integrating an additional integrated circuit layer. The 3D integration was realized by Ge-on-insulator (GOI) complementary metal oxide semiconductor field effect transistors (CMOSFETs) on 1-poly-6-metal (1P6M) Si devices, where little performance degradation was measured in the lower layer Si MOSFETs, due to the inherent low thermal budget (500°C rapid thermal anneal) of the GOI processing. The drive current of the 3D GOI n- and p-MOSFETs was more than double that of the control Si devices, providing another advantage of the approach.

The Irish Sea: Nutrient status and phytoplankton

Historical nutrient and phytoplankton data from the Irish Sea are reviewed in the light of recent studies. Mean late winter concentrations of dissolved inorganic nitrogen (DIN as NO 3 − + NO 2 −), dissolved inorganic phosphate (DIP as PO 4 3 − ) and silica (Si as SiO 2) in offshore near-surface waters are 8.3, 0.7 and 6.6 μM, respectively. Concentrations in inshore waters of the eastern Irish Sea can reach 57 μM DIN, 5 μM DIP and 17 μM Si. The northwards residual flow through the Irish Sea (≈ 5 km − 3 d − 1 ) is estimated to deliver ≈ 82 × 10 3 t DIN and 12 × 10 3 t DIP during the winter period. The annual freshwater inputs of DIN (including ammonium) and DIP are 123 and 9 × 10 3 t, respectively. Offshore waters of the western Irish Sea are enriched with DIN and DIP (≈ 3.0 and 0.4 μM, respectively) relative to Celtic Sea shelf break concentrations but salinity DIN relationships show that measured winter concentrations are lower than predicted. Denitrification is considered a key process limiting nitrogen enrichment of the Irish Sea. The onset and duration of the production season is controlled by the sub-surface light climate. Differences in depth and tidal mixing in the Irish Sea give rise to regional variation in the timing and length of the production season. Maximum spring bloom biomass in coastal and offshore waters of the western Irish Sea (23 and 16 mg chlorophyll m − 3 , respectively) compares with values of up to 44 mg chlorophyll m − 3 in Liverpool Bay and elevated production and biomass in the latter is attributed to enrichment. There is no evidence that enrichment and changes in nutrient ratios have caused major shifts in phytoplankton composition in Liverpool Bay. Species of Phaeocystis are found throughout the region in most years and together with other microflagellates can dominate the spring bloom. Red tides of dinoflagellates are rare events in the Irish Sea but regular monitoring of phytoplankton in the vicinity of shellfish beds has revealed the presence of toxin-producing dinoflagellates in the Irish Sea.

Characterization of the effective mobility by split C( V) technique in sub 0.1 μm Si and SiGe PMOSFETs

The feasibility of split C– V measurements is successfully demonstrated on sub-0.1 μm Si MOSFETs. A novel improved methodology to extract accurately the effective channel length and the effective mobility is thus proposed. Unlike conventional I d( V g) based extraction techniques, this new approach does not assume the invariance of the effective mobility with gate length. The method is successfully applied to advanced Si and SiGe PMOSFETs down to 50 nm.