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We investigated the energy resolution of a segmented silicon strip detector for photon-counting spectral computed tomography (CT). The detector response to different monochromatic photon energies a ...

An edge-on silicon strip detector designed for photon-counting spectral computed tomography (CT) is presented. Progress on the development of an application specific integrated circuit (ASIC) to pr ...

This article presents a Monte Carlo simulation of the detector energy response in the presence of pileup in a segmented silicon microstrip detector designed for high flux spectral computed tomography with sub-millimeter pixel size. Currents induced on the collection electrode of a pixel segment are explicitly modeled and signals emanating from events in neighboring pixels are superimposed together with electronic noise before the entire pulse train is processed by a model of the readout electronics to obtain the detector energy response function. The article shows how the lower threshold and the time constant of the electronic filters need to be set in order to minimize the detrimental influence of cross talk from neighboring pixel segments, an issue that is aggravated by the sub-millimeter pixel size and the proposed segmented detector design.

Si-LDMOS transistor is studied by TCAD simulation for improved RF performance. In LDMOS structure, a low-doped reduced surface field (RESURF) region is used to obtain high breakdown voltage, but it reduces the transistor RF performance due to high on-resistance. The interface charges between oxide and the RESURF region are studied and found to have a strong impact on the transistor performance both in DC and RF. The presence of excess interface state charges at the RESURF region results not only higher DC drain current but also improved RF performance in terms of power, gain and efficiency. The most important achievement is the enhancement of operating frequency and RF output power is obtained well above 1 W/mm up to 4 GHz.

The switching behavior of a previously fabricated and tested SiC transistor is studied in Class-C amplifier in TCAD simulation. The transistor is simulated for pulse input signals in Class-C power ...

The design of power transistors for microwave applications requires a good understanding of their large signal behaviour in a real circuit context. The computational load-pull simulation technique ...

Summary Background: The association between social position, living environment and nasal symptoms is inconsistent. We wanted to test how living environment, occupation and social position were associated with nasal symptoms. Methods: In a postal survey study of a random sample of 12,079 adults, aged 20–59 years living in the southern part of Sweden the relationship between nasal symptoms, socioeconomic status and environmental factors was analysed. Results: The response rate was 70% (n ¼ 8469) of whom 33% reported significant nasal symptoms. Nasal discharge, thick yellow discharge, a blocked nose, sneezing and itching were strongly associated with living close to heavy traffic or living in cities Most of the nasal symptoms provoked by extrinsic factors were more frequently reported among subjects who lived close to heavy traffic and in cities. Apart from thick yellow discharge and nasal symptoms provoked by damp/cold air which were more common in the socio-economic position ‘‘low’’ no relation to the socio-economic group was found. The prevalence of self-reported hay fever was neither affected by site of living nor by socio-economic status. Nasal symptoms evoked by ‘‘allergic’’ factors were linked to asthma but symptoms evoked by non-allergic factors were linked to chronic bronchitis/emphysema CBE. Conclusions: To conclude, we found a strong relation between geographical site and the prevalence of self-reported nasal symptoms which emphasizes the environment as a risk factor for nasal symptoms. Only by merging the socio-economic groups into ‘‘low’’ and ‘‘middle/high’’ an association to nasal symptoms was apparent. Nasal symptoms evoked by ‘‘allergic’’ factors were linked to asthma but symptoms evoked by ‘‘non allergic factors’’ were linked to CBE. r 2003 Elsevier Science Ltd. All rights reserved.

We have synthesized a new compound with formula Re4As6S3 and characterized its crystal structure by Rietveld powder diffraction methods. Re4As6S3 crystallizes in an face-centered cubic unit cell, space group F (4) over bar 3m (no. 216), with lattice constant a = 9.8608(1) Angstrom and Z = 4. The rhenium atoms form tetrahedral clusters linked via tetrahedral arsenic clusters to produce an NaCl-type arrangement. The oxidation state of rhenium is IV and the number of electrons shared by the rhenium atoms in the cluster is 12. The structure is based on an ordered defect thio-spinel A((1-x))B(2)X(4) where the B-type atoms form tetrahedral clusters. (C) 2003 Elsevier Science (USA). All rights reserved.

Background: Symptoms of seasonal allergic rhinitis may vary greatly. Hence, for research purposes, there is a need for disease-like models of allergic rhinitis. In a preliminary study, involving 7 days' challenge with allergen, promising symptom consistency was obtained and dose-response to a glucocorticosteroid could, in part, be demonstrated. Objective: To establish this model of seasonal allergic rhinitis and test the hypothesis that mometasone furoate is more potent than budesonide as an antirhinitis drug. Methods: Thirty-eight patients with seasonal allergic rhinitis received treatment with spray-formulations of placebo, budesonide 64 kg, budesonide 256 mug, and mometasone furoate 200 mug in a double-blind, crossover design. After 3 days' treatment, individualized nasal allergen-challenges were administered daily for 7 days while the treatment continued. Nasal symptoms and peak inspiratory flow (PIF) were recorded. Results: During the last 3 days of allergen challenge without active treatment, consistent around-the-clock symptoms were recorded and recordings during these days were used in the analysis. With few exceptions the active treatments reduced nasal symptoms and improved nasal PIF (P values

We have investigated the crystal structures of CsLnFe(CN)6·nH2O (Ln=lanthanide, n=4,5), as well as TlTmRu(CN)6·3H2O. These phases can be thought of as derivatives of LnFe(CN)6·4H2O, where, simultaneously, an alkali ion (or Tl+) is introduced while the valence of Fe is reduced from Fe3+ to Fe2+. A new arrangement of the structural units is observed in the CsLnFe(CN)6·5H2O, where the coordination of the Ln-ion is changed to a bisdisphenoid. The resulting LnN5O3 units alternate with Fe(CN)6 units to form an overall rocksalt-type ralted lattice that accommodates the alkali ions in interstitial sites. Due to the arrangement of the water molecules, a layer structure results.

It has been difficult to demonstrate dose-dependent clinical effects of anti-allergic glucocorticosteroid drugs in allergic rhinitis.To determine dose-dependent effects on rhinitis symptoms of clinical doses of the glucocorticosteroid budesonide in a standardized daily allergen challenge model.Twenty-five patients with seasonal allergic rhinitis were examined outside the pollen season. The highest 256 microg once daily and lowest 64 microg once daily clinically recommended doses of budesonide aqueous nasal spray and placebo were given in a double-blind, placebo-controlled, randomized, and crossover design with 4 weeks' washout between treatments. After 1 week's treatment, the patients received individually titrated nasal allergen challenges once every morning for 8 days while treatment continued. Nasal symptoms were scored in diary cards. Nasal symptoms from the 6th to the 8th challenge days were used in the analysis.The provocation model produced clinically relevant, and around the clock well tolerable rhinitis symptoms, suggesting that after several days of repeated allergen challenges, a season-like, transient allergic disease condition had been established. Both 64 microg and 256 microg of budesonide aqueous nasal spray reduced nasal symptoms. Budesonide 64 microg reduced total nasal symptoms scores from 5.19 +/- 0.5 to 4.23 +/- 0.53 (P.05), and budesonide 256 microg reduced total nasal symptoms scores to 3.41 +/- 0.51 (P.001). A significant difference in nasal symptoms after challenge between budesonide aqueous nasal spray 64 microg and 256 microg (P = .03), indicated a dose-dependent effect.A dose-dependent, symptom-reducing effect of once-daily treatment with topical aqueous nasal sprays of budesonide for two weeks was demonstrated, suggesting that this model is relevant for assessments of dose-dependent effects of anti-inflammatory drugs.

The main idea of this paper is to compare the readout architectures for uncooled microbolometer focal plane detector arrays with respect to the detector and readout circuit noise. The comparison is done keeping the total power consumption of all architectures constant. Three CMOS readout architectures with different degree of parallelism are described in this paper: pixelwise, columnwise and serial. The noise model of the readout circuit is given. Also, the optimization for the lowest NETD (noise equivalent temperature difference) and estimation of the self-heating effect is presented.

The crystal structure of Ba11Fe8Ti9O41 was determined using single crystal and powder X-ray diffraction methods. This new phase crystallizes in the hexagonal space group P63/mmc (No 194) (a=5.7506(3) A, c=61.413(2) A; Z=2; ρcalc.=5.75 g cm−3) and exhibits a 26-layer structure built from close-packed [O,(Ba,O)] layers with a stacking sequence (chcchchchcchc)2. Octahedral sites are occupied by a mixture of Fe3+ and Ti4+, with some preferential ordering of the Fe ions, and tetrahedral sites are occupied by Fe3+. The magnetic Fe ions were observed to concentrate within four contiguous cp layers around z=1/4 and 3/4. Unusual structural features, including cation disorder associated with unreasonably short cation–cation separations, were observed to occur within these magnetic sections of the structure. Indexed X-ray powder diffraction data for polycrystalline Ba11Fe8Ti9O41 are given. Complementary structural studies of this compound using neutron and electron diffraction are underway and will be described elsewhere along with the results of dielectric and magnetic property measurements.

A new forecasting model for predicting the need for fungicide applications for Sclerotinia stem rot on oilseed rape is presented. Logistic regression was used for calibration and receiver operating characteristic (ROC) curves were used to compare different models. Data from about 800 fields collected during a 10-year period were used in the analysis. The new forecasting model is a risk point table based on field specific data and precipitation. Six factors that affect Sclerotinia infection (number of years since last oilseed rape crop, disease incidence in last Sclerotinia host crop, crop density, rain in the last 2 weeks before flowering, weather forecast and regional risk for apothecium development) are given points with regard to the risk of heavy infestation. The new model was tested in 48 fields during 1996 and 30 fields during 1997 and predicted the need for fungicide applications with high accuracy. At a given risk point threshold, spraying recommendations were given in 75% of the fields that needed fungicide application and in 16% of the fields that did not need to be sprayed. If a lower threshold was used, spraying was recommended in more fields in need of spraying but also in more fields that did not need to be sprayed.

Synthesis, crystal structure, enantiomeric resolution, and CD spectroscopy of the first colchicine derivative with an eight-membered B-ring lactam obtained via a Beckmann reaction, is described and only one of the stable atropisomeric enantiomers arrests microtubule assembly.

Background: Microvascular-epithelial exudation of bulk plasma may characterize inflammatory airway diseases. This study compares the acute allergen challenge–induced mast cell and exudative responses in nasal and bronchial airways. The focus is on α 2 -macroglobulin as an index of luminal entry of plasma exudates. Methods: Separate nasal and bronchial allergen challenges were carried out outside the pollen season in eight patients with pollen-induced seasonal allergic rhinitis. The levels of different-sized plasma proteins (albumin molecular weight, 66,000 d and α 2 -macroglobulin molecular weight, 725,000 d) and tryptase were determined in pre- and postchallenge nasal lavage and bronchoalveolar lavage (BAL) fluids. Diluent and increasing doses of allergen were sprayed into the right nasal cavity, and each challenge was followed by a nasal lavage (volume, 15 ml) with a "nasal pool" device (recovery, >80%). Endobronchial allergen challenge (individual doses) and BAL (volume, 2 × 25 ml) were performed in a lobe bronchus through a fiberoptic bronchoscope (recovery, 30%). Saline challenge and BAL were carried out in the contralateral lung as control. Results: The levels of albumin, α 2 -macroglobulin, and tryptase increased dose-dependently in postchallenge nasal lavage fluids ( p 2 -macroglobulin correlated ( r = 0.98, p 2 -macroglobulin and tryptase, but not albumin, were increased in BAL fluids from the allergen-challenged side ( p Conclusion: Local allergen challenge causes luminal entry of tryptase and α 2 -macroglobulin in the nose and bronchi of patients with allergy. We suggest that mast cell and plasma exudation responses may be similar in human nasal and bronchial airways and that albumin levels (in BAL fluids) may not well reflect the exudation process in bronchial airways. (J ALLERGY CLIN IMMUNOL 1995;96:239-46.)

Background: Despite the wide use of antihistamines in the treatment of allergic rhinitis, little is known about effects of these drugs on airway mucosal indices, which specifically reflect either mast cell release activity (tryptase) or microvascular-epithelial exudation of bulk plasma (α 2 -macroglobulin). Objective: This study, involving subjects with seasonal allergic rhinitis, examines the effects of loratadine treatment on allergen-induced nasal mucosal output of tryptase and α 2 -macroglobulin. Effects on nasal symptoms and eosinophils are also examined. Methods: Placebo and loratadine (20 mg) were given orally once daily for 5 days at 6-week intervals. Nasal diluent and allergen challenges were carried out on day 5. The mucosa was lavaged with saline solution after each challenge, and nasal lavage fluid levels of tryptase and α 2 -macroglobulin were determined. Nasal symptoms were scored, and nasal peak expiratory flow rates were measured. Superficial cells (eosinophils) were obtained with a brush device before and 24 hours after the allergen challenges. Results: Allergen dose-dependently increased the nasal symptoms and the lavage fluid levels of α 2 -macroglobulin and tryptase. Allergen also reduced the nasal peak expiratory flow rates. Loratadine inhibited the exudation of α 2 -macroglobulin and reduced tryptase levels, nasal symptoms, and obstruction, but did not affect the number of eosinophils. Conclusion: The inhibitory effects of loratadine on nasal lavage fluid levels of α 2 -macroglobulin suggest that histamine, through effects on microvascular H 1 -receptors, mediates allergen challenge–induced exudation of bulk plasma in acute allergic rhinitis. The reduced lavage fluid levels of tryptase suggest either that loratadine directly attenuates mast cell release activity or that loratadine, through inhibition of the exudation process, simply attenuates luminal entry of tissue solutes (in this case, tryptase). (J Allergy Clin Immunol 1995;96:97-103.)

The coadsorption of Na and CO on Cu(111) has been investigated with high resolution electron energy loss spectroscopy for low and intermediate submonolayer precoverages of Na. On coadsorption with Na the CO stretch vibration frequency is strongly reduced. From the sequential appearance of loss peaks upon CO exposure we find, in contrast to previous observations made for alkali/CO coadsorption systems, that at low Na precoverage the molecules prefer sites corresponding to the high stretch frequency characteristic of the Na-free substrate (255 meV) rather than sites with a strongly reduced frequency (180–210 meV). At intermediate Na precoverages the loss characteristic of Na-substrate vibrations (at 21 meV loss energy) shows a drastic intensity increase on CO exposure. This is ascribed to a reduced screening of the field from the incoming electrons, when due to CO adsorption, the Na layer loses valence electrons and thereby its metal character.

We describe the digital filter section of the FERMI readout microsystem. The filter section, consisting of two separate filter blocks, extracts the pulse amplitude and time information for the first-level trigger process and performs a highly accurate energy measurement for higher-level triggering and data readout purposes. An FIR-order statistic hybrid filter structure is used to improve the amplitude extraction performance. Using a training procedure the filters are optimized to produce a precise and accurate output in the presence of electronics and pile-up noise, sample timing jitter and the superposition of high-energy pulses. As the FERMI system resides inside the detector where accessibility is limited, the filter implementations are presented together with fault tolerance considerations. The filter section is modelled with the VHDL hardware descriptive language and the subsystems are further optimized to minimize the system latency and circuit area.

Conducting polymers appear very attractive as sensor materials either as the gas-sensitive component or as a matrix for easy immobilization of a specific substrate. The planar Schottky barrier diod ...

Extracts of the culture filtrate of the fungus Merulius tremellosus, from which isolactarane and sterpurane sesquiterpenes previously have been isolated, has yielded a sesquiterpene lactone with a novel skeleton and a pentacyclic aldehyde. The structures of the compounds were determined by mass and NMR spectroscopy and by X-ray structural analysis.

When Na (K) is adsorbed on Cu(111) and the coverage is below half of a full monolayer electron energy loss spectra show a peak at 21 meV (13 meV) ascribed to the excitation of Na (K) vibrations perpendicular to the surface. From the intensity of the loss peak at low alkali metal coverage a dynamic charge of approximately 0.5e (0.6e) is obtained assuming dipolar scattering. The value agrees well with theoretical estimates obtained from the dependence of the induced dipole moment on the distance from the substrate surface and provides strong support for the description of the adsorbate as partly ionic at low monolayer coverages. If the Na covered Cu(111) surface is exposed to water vapour there is a rapid uptake only if there is more than 10% of a full monolayer of Na on the surface. The existence of a Na precoverage threshold is revealed by the exposure induced vibrational losses and work function changes. Above threshold there is, upon H 2 O exposure, an increase of the work function and strong changes in the low loss energy region of the electron energy loss spectra with peaks appearing at 18 meV and 36 meV loss energy.

Purpose : The purpose of this study was to evaluate our treatment results of anal cancer. Methods and Materials : During the years 1985–1990, 82 patients with invasive epidermoid anal cancer were referred to the Department of Oncology at Sdersjukhuset. In 76 cases irradiation was used in the primary therapy, and in 43 cases bleomycin was administered concurrently. Fifteen of these tumors were situated in the perianus and 61 in the anal canal. Probability of survival, recurrence, and preservation of anal sphicter was analyzed according to Kaplan-Meier. Cox multivariate analysis was used in studying potential determinants of risk for treatment failure. Results : Tumor-specific survival at 5 years was 71% for both anal canal and perianal cancer. Analyses with regard to cancer of the anal canal indicated that T4 tumors had significantly worse prognosis than those in stages TI-3. Overall survival was 73% and 79% at 5 years for T1 and T2 tumors and 73% and 18% at 4 years for T3 and T4 tumors. Corresponding figures for tumor specific survival were 79%, 79%, 82%, and 31%. Eighty-five precent of patients with T1 tumors, has a preserved anal sphincter after 4 years. For T2 and T3 tumors the corresponding figures were 62% and 60%. Also the multivariate analyses showed t$ to be a strong negative prognostic determinant. There was no firm evidence of a positive effect of bleomycin on the treatment results, but it increased the acute radiation toxicity. Conclusion : Primary radiotherapy of anal cancer yielded a high probability of survival, but in many cases sphincter amputation have been necessary. The role of bleomycin appears questionable.

The changes of the size of gamma/delta T (gamma delta T) and alpha/beta T (alpha beta T) cell subsets in the blood were examined after radiation therapy (66 Gy) for prostatic carcinoma in 17 men. Following radiation both subpopulations of T cells were reduced to 52% and 36% of starting values, respectively. gamma delta T cells were not replaced four months after radiation therapy, in contrast to alpha beta T cells, which were increased to 47% of initial values. The T alpha beta/T gamma delta ratio was significantly reduced immediately after radiation therapy but was normalised after four months. Blood gamma delta T cells may be reduced for a long time after radiation therapy and this may be true also for gamma delta T cells in irradiated epithelial organs and tumours.

In this paper fabrication and characterization of Schottky gate planar field-effect transistors using poly(3-alkylthiophene) as an active semiconductor region are reported. This is the first time that planar MESFET transistors utilizing a polymer semiconductor have been fabricated and measured. Aluminum metal is used for the rectifying contact and two gold electrodes are constructed as source and drain. From the MESFET characteristic the channel carrier mobility is evaluated as 10 −5 cm 2 V −1 s −s , which is one order of magnitude larger than a MOSFET utilizing the same polymer.

A personal description of the history of gas-sensitive field-effect devices is given. It is shown how the originally described palladium-gate metal-oxide-semiconductor field-effect transistor has developed into sensing surfaces enabling the production of response images to odours. Images obtained for the odour from different cheeses are presented as examples of such ‘artificial olfactory images’.

Electronic devices based on organic semiconductors, mainly conjugated polymers, have recently been reported. In this paper characterization and improvements of three devices will be presented, namely, Metal Oxide Semiconductor Field Effect Transistors (MOSFET), Schottky barrier diodes and Schottky gated Field Effect Transistors (MESFET). The MOSFET devices work through the modulation of an accumulation layer at the semiconductor (polymer)-insulator interface. A model for organic MOSFET is proposed by changing the classical equations according to this particular operating mode. It is shown that, the characteristics of these organic devices can be improved by controlling the doping in certain level and decreasing the thickness of the semiconducting (polymer) layer. The mobility also increases with the gate bias in contrast to inorganic semiconductor. A planar Schottky barrier diode is successfully fabricated and reported, using poly (3-alkylthiophene) as an active semiconductor and aluminium and gold electrodes are used as Schottky and ohmic contacts. The electrical characteristics of the poly (3-alkylthiophene) / metal interfaces have been studied. Electrical characterization reveals diode behaviour with a rectification ratios larger than 104 at sufficiently high voltage. The ideality factor (n) is as low 1.2. Possible transport mechanisms are discussed. In this paper also fabrication and characterization of Schottky gated planar field effect transistors using poly(3-alkylthiophene) as an active material are reported. Aluminium is used for the rectifying contact and two gold electrodes are used as source and drain. From the MESFET characteristic the channel carrier mobility is evaluated to be 10−5 cm2/Vs, which is one order of magnitude larger than than mobility found from an MOS transistor using the same polymer.

When Na-covered Cu(111) is exposed to water vapour the adsorption proceeds rapidly only if the amount of Na on the surface is greater tha 10% of full monolayer coverage. The adsorption is monitored via the electron energy loss spectrum which for the coadsorption system shows vibrational excitations at 18 and 36 meV while for Na on Cu (111) the adsorbate vibrations perpendicular to the surface produce a loss peak at 21 meV.

The red pigments exudated from Drechslera teres, D. graminea, D. tritici-repentis, D. phlei, D. dictyoides, D. avenae and Bipolaris sorokiniana , were extracted and isolated by means of thin-layer chromatography and/or high-performance liquid chromatography. Chemical characterization was made by spot-tests, uv-vis spectrophotometry and 1 H-nuclear magnetic resonance spectroscopy. The red pigment produced by the five first-mentioned Drechslera species was identified as the anthraquinone catenarin while that form D. avenae and B. sorokinana consisted of two other anthraquinones — cynodontin and helminthosporin. Catenarin was totally inhibitory against the Gram-positive bacterium Bacillus subtilis but not the Gram-negative bacterium Erwinia carotovora . However, catenarin could also partly inhibit the mycelium of D. teres itself.

Rectifying contacts between poly(3-hexylthiophene) and Indium-Tin oxide or Aluminum have been studied by means of current-voltage measurements and capacitance-voltage measurements. The results show that the current transport through these contacts is not well described by conventional thermionic emission theory. Furthermore, the dopant distribution is not homogeneous in the polymer. Dopants accumulate near the polymer/metal interface. This accumulation can be enhanced by means of an electric field applied across the structure.

This study examined plasma- and eosinophil-derived products in nasal lavage fluids obtained from patients with hay fever during natural allergen exposure. Nine patients with strictly seasonal allergic rhinitis and five normal, nonallergic subjects (control group) were studied. Nasal lavages were performed twice weekly, starting 1 week before the expected birch-pollen season and continuing for 6 weeks, thereby covering the entire birch-pollen season. Nasal symptoms and pollen counts were recorded daily. The lavage fluid was analyzed for it content of albumin, bradykinins, and eosinophil cationic protein (ECP). During the pollen season, each of these solutes was significantly increased in the nasal lavage fluid from the allergic patients (p less than 0.05) but not from the control subjects. Albumin, bradykinins, and ECP generally correlated better between themselves than with symptoms and pollen counts. We conclude that natural exposure to allergens induces plasma exudation and increased levels of ECP on the human nasal mucosa.

We report studies of the transport properties of thin films of the neutral polymer poly(3-alkylthiophene). Our measurements were done using a field effect transistor structure, which allows measurements of the mobility of the charge carrier in the film, as well as the conductance. We have also studied the temperature dependence of these parameters. The field effect mobility in the channel was found to be typically 10−5 cm2/Vs. (with a surface conductance of 10 −8 1 μ and a density of charge carriers of 1011 cm−2 at room temperature). The field effect mobility in the channel was found to decrease with temperature, partly reversibly and partly non-reversible. The decrease of mobility with temperature may possibly be related to the formation of conjuction defects on the polymer, leading to loss of planarity and decreasing conjugation lengths.

The capacitance vs voltage curve of thin oxide (30–40 A) MOS structures in strong accumulation was studied. The results were interpreted in terms of equivalent surface density of state masses, which was found to be 0·2 m 0 for the silicon valence band and 0·06 m 0 for the conduction band, for both 111 and 100 surfaces. The experimental density of state masses were shown to be much lower than the bulk values. Equivalent density of states masses were calculated from a surface quantization model and in this case agreement with the experiments was obtained for the valence band only.

A simple extension to the standard nonoverlapping two phase clocking strategy, allowing a considerable clock skew between different isochronic regions is suggested. It is shown how this strategy can be further extended to other clocking strategies and to clock skews of more than half a clock period.

The crystal structure of NaIO3 at 293 K has been refined from MoKα data in space group Pbnm, Z = 4, Mr 197.89, a = 5.7500(3), b = 6.3953(4), c = 8.1280(4), A, V = 298.89(5), A3. Three thousand eighty-five (857 unique) reflections refined to R(F) = 0.018. The iodate group forms a pyramid with I as one apex; the IO bond distances are 1.8016(8) and 1.8112(7) A, and the OIO angles are 96.43(4)° and 102.60(3)°. Including next-nearest neighbors at distances 2.95–3.30 A the IO coordination is described as a two-capped trigonal prism. NaIO3 is of the anti-cementite type, with Na occupying octahedral interstices (empty in cementite) and with the I lone pair approximately in the cementite C position.

It is pointed out that metal-oxide-semiconductor structures can be used to stfidy catalytic reactions on metal surfaces (like Pd and Pt surfaces). The flatband voltage shift induced by hydrogen at the metal-oxide interface is a measure of the amount of hydrogen in the metal, which in turn reflects the chemical reactions on the surface. Experimental results on hydrogen in argon and in air detected with Pd-MOS structures are compared with absolute reaction rate theory. The agreement between theory and experiments is surprisingly good.

The noise behavior of a Static Induction Transistor (SIT) has been studied. The SIT transistor has a relative high noise level for the low and middle frequency range and it increases with decreasing temperature. Spectral analysis for different temperatures has been carried out. Observation of the noise spectra indicates generation-recombination noise from a single energy level trap. An activation energy of 0.13 eV has been measured which might originate from a previously observed SiO complex in the bulk, this may be an important noise source in the SIT.

We have performed ESR measurements on oxidized (111) silicon wafers and found two ESR centers. One, the previously known Pb center,was found to be a two level interface trap by corona bias studies. The other one, previously known as “damaged silicon” center was found to be a silicon center, probably related to the oxide growth process.

A model for a vertical metal base transistor is proposed. A virtual base is created by a hole-plasma which is maintained by injection of holes from a forward biased Schottky-diode. By using a Schottky-barrier controlled plasma instead of a controlled p — n -diode, the good power handling capabilities of the BSIT can be combined with improved speed performance. This is obtained by the low base spreading resistance. The metal is placed as a buried grid between the emitter and the collector on intrinsic or weakly doped silicon. The metal is oxidized to protect the base from n + doped emitter. A possible model for the transistor is given and the current gain is calculated. The injection efficiency is discussed in consideration with the design of the base and emitter. Different designs of the transistor are discussed with respect to possible fabrication techniques.

The discharge behavior of MNOS structures without voltage applied, is investigated at temperatures from 25 to 300°C, for times from 10 min to about 1 week. The observed discharge behavior is explained by a theoretical model, including two discharge processes. The two processes are direct tunneling from traps and thermal excitation of these traps. It is shown that static retention times of more than 10 yr at 85°C is attainable. Also, discharge with voltage applied is investigated and shown to agree with the model when the voltage is small enough.

The low frequency noise voltage spectrum for a MOS transistor is calculated under the assumption that a time constant dispersion, giving a 1/ƒ- spectrum , is caused by tunneling of carriers at the silicon-silicon oxide interface to traps located inside the oxide. The magnitude of the noise from different trap distributions is calculated. The largest noise contribution is shown to come from traps near the quasi Fermi level of the current carriers in the channel. The influence of temperature and operating point on the noise is examined. The theoretically predicted noise magnitude agrees with the experimental results (presented in Part II). The theory presented describes qualitatively the shape of the low frequency noise spectrum.

A FAMOS cell may be unintentionally written during repeated reading. The temperature dependence of this failure process was studied and it is shown that the worst case for unintentional charging of a FAMOS device occurs at low temperatures. This is qualitatively explained by a simple model including the temperature dependence of preavalanche carrier multiplication and hot electron injection.

It is shown that hydrogen in the ambient atmosphere changes the flatband voltage of palladium gate MOS-structures. The physical mechanisms behind this phenomenon are discussed. Experimental results on the detection of hydrogen in air, argon and nitrogen are given. It is shown that the rate constants of chemical reactions on the Pd-surface are obtained from such experiments. The detection of hydrogen in hydrogen compounds like ammonia and of hydrogen in smoke is also demonstrated.

Tunnel currents vs oxide voltage have been measured on thin (30–40 A) oxides on heavily doped p -type silicon. At the onset of Fowler-Nordheim tunneling, oscillations in the current vs oxide field curve were observed. These oscillations show excellent agreement with resonances occuring in the triangular potential well defined by the top of the oxide conduction band and the oxide-silicon interface.

An increase in flow stress in ZnO under illumination was observed. Measurements of this effect are presented and a model is proposed for the explanation.

The discharge of MNOS memory devices at zero or low gate voltages is studied theoretically and experimentally. A theory based on direct tunneling of charge carriers from traps in the silicon nitride layer into the silicon describes the experiments quite well. The discharge process is found to be logarithmic in time, starting at a certain time, ift d , which is exponentially dependent on the oxide thickness, and ending at another time, extrapolated to much larger than 10 years. Some implications of the discharge model are discussed.