Thick-Film and LTCC Passive Components for High-Temperature Electronics

At this very moment an increasing interest in the field of high-temperature electronics is observed. This is a result of development in the area of wide-band semiconductors’ engineering but this also generates needs for passives with appropriate characteristics. This paper presents fabrication as well as electrical and stability properties of passive components (resistors, capacitors, inductors) made in thick-film or Low-Temperature Co-fired Ceramics (LTCC) technologies fulfilling demands of high-temperature electronics. Passives with standard dimensions usually are prepared by screen-printing whereas combination of standard screen-printing with photolithography or laser shaping are recommenced for fabrication of micropassives. Attainment of proper characteristics versus temperature as well as satisfactory long-term high-temperature stability of micropassives is more difficult than for structures with typical dimensions for thick-film and LTCC technologies because of increase of interfacial processes’ importance. However it is shown that proper selection of thick-film inks together with proper deposition method permit to prepare thick-film micropassives (microresistors, air-cored microinductors and interdigital microcapacitors) suitable for the temperature range between 150°C and 400°C

L'acoustique passive appliquée à l'étude du comportement des corégones (Coregonus sp. et C. Lavaretus) durant la reproduction en milieu naturel

L'acoustique passive (étude des bruits propres du milieu environnant) constitue une méthode simple, sinon facile, d'étude de l'activité et du comportement de la faune aquatique.Nous décrivons ici les systèmes de prise de son et d'analyse utilisés à cet effet à l'Institut de Limnologie (Thonon-les-Bains) et rapportons certains résultats d'observations réalisées sur les zones de fraie des corégones (Coregonus lavaretus) du lac d'Aiguebelette et des ombles chevaliers (Salvelinus alpinus du lac d'Annecy : l'activité de fraie des corégones est caractérisée par des bruits brefs (0,5 à 2 s) de type "stridulation"; certains bruits de "fouille" sur substrat d'une omblière semblent directement associés à l'activité prédatrice des lottes (Lota lota) sur la ponte.Listening to underwater sound is a simple way of studying the activity and behaviour of aquatic fauna.The material used in the Institute of Limnology (Thonon-les-Bains) for recording and analysing sounds is described (figure 2). Experiments have been performed on the spawning sites of coregonids (Coregonus lavaretus) in Lake Aiguebelette and of charrs (Salvelinus alpinus) in Lake Annecy. This paper refers mainly to observations made in December 1987 on the site of "Roc de Chère" in Lake Annecy; this is where the charrs spawn and the site is easy to survey (figure 1). Most of the work consisted in continuous visual and acoustical observations, in order to determine the origin of the sounds recorded. A great part of the period was noisy because of water disturbance (wind-induced waves).The most interesting aspect is the study of sounds produced by fish (figure 3). We could not record the activity of the charrs, because of the inconvenient area studied : the observation field was limited to 1 sq.metre, which is very small in comparison to the spawning zone (figure 1). The presence of burbot (Lota lota) in the field of the video camera suggested that these fish came and ate the charr eggs which had been deposited on the bottom. This hypothesis was confirmed by the continuous digging activity (which was heard and recorded) due to the burbot feeding and by an analysis of the stomacal content of specimens, caught white SCUBA diving, which contained fertile eggs. Though acoustically evident, burbot activity was not analysed.The coregonids found in Lake Annecy (1987) (C. species) have the same behaviour as those found in Lake Aiguebelette (1986) (C. lavaretus, a different species). Typical, short (0.5-2 s) stridulating noises are produced during courtship, when the male and the female rub against each other; these noises, nearly always the same, have been analysed (figure 4). The loudest sounds emitted are in the 100-300 Hz range.Another aspect of fish activity has been studied : the noise made by coregonids swimming (figure 4). During courtship, fish is very active and swims energetically. The low frequency of the sound has been recorded by using a special electronic device.All these observations are in accordance with the results presented in the literature. Acoustical observation is an interesting method which should be developed

Modern Microelectronic Technologies in Fabrication of RFID Tags

This paper presents fabrication of RFID tags, especially antennas for HF band (13.56 MHz), on cheap flexible substrates. The physicochemical, geometrical, DC and AC electrical properties as well as long-term stability (under thermal, moisture-thermal and mechanical exposures) have been characterized for several low-temperature polymer thick-film conductive films made on various paper or foil substrates. Resistance measurement during curing has been used for investigation of polymerization velocity, which is very important for increase of process capacity

Tunneling-percolation origin of nonuniversality: theory and experiments

A vast class of disordered conducting-insulating compounds close to the percolation threshold is characterized by nonuniversal values of transport critical exponent t, in disagreement with the standard theory of percolation which predicts t = 2.0 for all three dimensional systems. Various models have been proposed in order to explain the origin of such universality breakdown. Among them, the tunneling-percolation model calls into play tunneling processes between conducting particles which, under some general circumstances, could lead to transport exponents dependent of the mean tunneling distance a. The validity of such theory could be tested by changing the parameter a by means of an applied mechanical strain. We have applied this idea to universal and nonuniversal RuO2-glass composites. We show that when t > 2 the measured piezoresistive response \Gamma, i. e., the relative change of resistivity under applied strain, diverges logarithmically at the percolation threshold, while for t = 2, \Gamma does not show an appreciable dependence upon the RuO2 volume fraction. These results are consistent with a mean tunneling dependence of the nonuniversal transport exponent as predicted by the tunneling-percolation model. The experimental results are compared with analytical and numerical calculations on a random-resistor network model of tunneling-percolation.Comment: 13 pages, 12 figure

Multisite peripheral joint pain: a cross-sectional study of prevalence and impact on general health, quality of life, pain intensity and consultation behaviour

Background Research into musculoskeletal conditions often focusses on pain at single sites, such as the knee, yet several studies have previously reported the high prevalence of multiple sites of musculoskeletal pain. The most common form of musculoskeletal condition is arthritis, with osteoarthritis (OA) the most common cause of joint pain in adults 45 years and over. However, there is limited recognition of the prevalence of multisite peripheral joint pain in those either living with or at risk of OA, therefore this study set out to estimate the prevalence of multisite peripheral joint pain in adults 45 years and older, and its impact on several dimensions of health. Methods A cross-sectional population survey was mailed to adults (n = 28,443) aged 45 years and over from eight general practices in the North West Midlands, United Kingdom (UK). Prevalence rates were established for multisite peripheral joint pain (pain in two or more sites; hands, hips, knees, feet). Impact was measured for general health (SF-12 MCS & PCS), QoL (EQ-5D), pain intensity (0-10 numerical ratings scale) and the number of consultations with a range of health care professionals. Results Of 15,083 responders (53%), multisite peripheral joint pain was reported by 54%. Peripheral joint pain was present in n = 11,928, of which 68% reported pain in multiple sites. Multisite peripheral joint pain was shown to be significantly associated with reduced physical (Mean difference = −5.9 95% CI -6.3,-5.5) and mental (−2.8 95% CI -3.2,-2.4) components of the SF-12, reduced QoL (−0.14 95% CI -0.15, −0.13), increased pain (+0.70 95% CI 0.62, 0.79) and increased odds of consultations with GPs (OR 2.4 95% CI 2.2, 2.6) and practice nurses (OR 2.6 (95% CI 2.1, 3.2) when compared to single site pain. Conclusions Multisite peripheral joint pain is prevalent in the population in adults 45 years and over and has a significant negative impact on several dimensions of health. Health care professionals should consider joint pain beyond the index site in order to address holistic management

Exercise for lower limb osteoarthritis : systematic review incorporating trial sequential analysis and network meta-analysis

Objective: To determine whether there is sufficient evidence to conclude that exercise interventions are more effective than no exercise control and to compare the effectiveness of different exercise interventions in relieving pain and improving function in patients with lower limb osteoarthritis. Data sources: Nine electronic databases searched from inception to March 2012. Study selection: Randomised controlled trials comparing exercise interventions with each other or with no exercise control for adults with knee or hip osteoarthritis. Data extraction: Two reviewers evaluated eligibility and methodological quality. Main outcomes extracted were pain intensity and limitation of function. Trial sequential analysis was used to investigate reliability and conclusiveness of available evidence for exercise interventions. Bayesian network meta-analysis was used to combine both direct (within trial) and indirect (between trial) evidence on treatment effectiveness. Results: 60 trials (44 knee, two hip, 14 mixed) covering 12 exercise interventions and with 8218 patients met inclusion criteria. Sequential analysis showed that as of 2002 sufficient evidence had been accrued to show significant benefit of exercise interventions over no exercise control. For pain relief, strengthening, flexibility plus strengthening, flexibility plus strengthening plus aerobic, aquatic strengthening, and aquatic strengthening plus flexibility, exercises were significantly more effective than no exercise control. A combined intervention of strengthening, flexibility, and aerobic exercise was also significantly more effective than no exercise control for improving limitation in function (standardised mean difference −0.63, 95% credible interval −1.16 to −0.10). Conclusions: As of 2002 sufficient evidence had accumulated to show significant benefit of exercise over no exercise in patients with osteoarthritis, and further trials are unlikely to overturn this result. An approach combining exercises to increase strength, flexibility, and aerobic capacity is likely to be most effective in the management of lower limb osteoarthritis. The evidence is largely from trials in patients with knee osteoarthritis

X-ray absorption near edge structure and Mössbauer spectroscopy in study of iron valence states in tissues

X-ray absorption near edge structure Fe K-edge spectra and $\text{}^{57}$Fe Mössbauer spectra of selected standard compounds were recorded at room temperature. Valence and spin states of Fe in these samples known from Mössbauer spectroscopy were correlated with the shapes of X-ray absorption near edge structure spectra in search of possible application of X-ray absorption near edge structure spectroscopy as analytical tool determining local electronic states of iron in tissues. As an example, the X-ray absorption near edge structure spectra of healthy and cancerous tissues of prostate are shown, suggesting Fe$\text{}^{3+}$ in cancerous tissues