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The idea that wireless LAN protocols can be customized so as to extend battery life in mobile devices has received considerable attention. We have previously reported experimentation and analysis of various methods for extending the lifetime of batteries in wireless devices. One area of our investigation has focused on the recovery effect and on a second battery effect, the rate capacity effect, and on their relative impact on the lifetime of Li-ion battery cells. Our experimental results support earlier non-experimental work that casts doubt on the efficacy of modifying protocols to take advantage of the recovery effect. In the work summarized here, we have augmented the previous work by comparing battery switching techniques, designed to exploit the recovery effect, to more conventional parallel cell connections which exploit the rate capacity effect. We show that the latter approach gives as good or better lifetime extension with simpler circuitry.

Objectives: The purpose of this paper was to suggest a new diagnostic method to estimate the electrical properties at acupoints. Thus, we developed a multi-frequency bioelectrical impedance measurement system to analyze the state of bioions in body fluids, not the skin impedance at an acupoint, for various body compositions. Methods: At low frequencies, the current does not penetrate the cell membrane, and at high frequencies, the current passes through both intracellular and extracellular fluids because of a decrease in the cell membrane’s impedance. To confirm the effect of the composition of an extracellular fluid or an intracellular fluid in a segment such as an acupoint, are developed a system to detect the acupoint potential at 5, 50 and 200 KHz between two adjacent points in the areas of LU3, LU4 and LU9. Results: The detected acupoint potential decreased with increasing frequency. A correlation analysis of identical left/right acupoints showed a high correlation for three types of acupoint potentials at multiple frequencies. Moreover, we observed a low correlation at 5 KHz, which is a significant factor to be considered for the unbalanced relationship between identical acupoints. Conclusions: On the basis of a meridian theoretical point of view, we may infer the acupoint’s physiological composition by using the multi-developed frequency bioelectrical impedance measurement system.

The purpose of this work is to clarify the relationship between some of the properties of MOS capacitors passivated by fluoride-containing zinc borosilicate glasses and the hydroxyl content of the glasses. Substitution of ZnF 2 for ZnO progressively decreases the OH - absorption coefficient and the C - V curve shift, Δ V G , in the MOS capacitors decreased. A good recovery without hysteresis was observed in the MOS capacitors passivated by glasses with a small concentration of OH - ions.

Hot carrier induced bipolar transistor degradation under dynamic stress is studied. The model, ΔIB ∝ (IR1.8 t)0.5, established from d.c. emitter-base reverse bias stress measurements is found to be still valid under pulse stress down to 20 ns pulse width, where ΔIB is drift of base current, IR is reverse emitter-base current under stress and t is stress time. Although partial degradation recovery is observed under d.c. emitter-base forward bias, ΔIB from alternating reverse-forward stress representative BiCMOS circuit operation agrees with the ΔIB model with no significant recovery effect. This is explained by a higher degradation rate after recovery of previous damage. An experimental basis of BiCMOS circuit reliability testing simulation is thus provided.

This paper introduces a stochastic model of battery behavior, that emulates electrochemical mechanisms that are key to battery performance under pulsed discharge conditions. A pulsed discharge allows charge recovery during the idle periods. Recovery depends on the state of charge of the battery and on the duration of the rest time period. Using the postulated model, we derive the improvement to battery lifetime that results from pulsed current discharge driven by bursty stochastic transmissions. The results emphasize the role of traffic shaping in the quest to enhance battery behavior.

A model for battery behavior taking into account the recovery effect is presented. The recovery capability of the battery is represented as an exponential function of both the state of charge and the discharged capacity of the battery. Using the proposed model, the benefits of the pulsed battery discharge relative to the constant discharge are shown. Then, we introduce a new battery management technique, that, exploiting the traffic shaping algorithm leaky bucket, allows us to optimize the gain obtained from the pulsed discharge and maximize the capacity obtained from the battery. Results presenting the effect of the proposed solution on the system performance are presented for different packet arrival processes.

Degradation characteristics for MBE grown Ga/sub 0.51/In/sub 0.49/P and GaAs single junction and Ga/sub 0.51/In/sub 0.49/P/GaAs tandem solar cells irradiated with 3 MeV and 10 MeV protons with fluences of 10/sup 10/- 10/sup 13/ cm/sup -2/ are reported. The cell degradation was characterized with illuminated current-voltage (I-V) and spectral response measurements. Minority carrier diffusion length damage coefficients for the GaAs cells for 3 MeV and 10 MeV protons were calculated as a function of fluence. The results were compared to the InP damage coefficients. In addition, photo-annealing recovery effect at temperatures of 35-60/spl deg/C under 1-Sun AM0 illumination on the Ga/sub 0.51/In/sub 0.49/P cells are presented.

Wireless networking has experienced a great deal of popularity, and significant advances have been made in wireless technology. However, energy efficiency of radio communication systems is still a critical issue due to the limited battery capacity of portable devices. In this paper, we deal with the charge recovery effect that takes place in electrochemical cells and show how we can take advantage of this mechanism to increase the energy delivered by a battery. Then, we present energy-aware traffic shaping techniques, as well as scheduling and routing algorithms, which exploit the battery recovery effect.

For the exchange biased polycrystalline FeNi/FeMn bilayers, we systematically studied the ferromagnet (FM) magnetization reversal pathway dependent recovery effect of training using a vector vibrating sample magnetometer. Our experimental results show unambiguously that the well-known recovery effect strongly depends on the FM magnetization reversal pathway in addition to the final FM magnetization orientation. If the FM magnetization rotates in two opposite directions, i.e., clockwise (CW) or counter clockwise (CCW), to the same final FM magnetization orientation, the recovery effect exhibits distinct asymmetry. For the present initial magnetization configuration, only the CW pathway induces recovery effect, whereas it is impossible to produce training recovery through the CCW pathway. This recovery asymmetry can be explained by considering the random distribution of antiferromagnetic grains' easy axes and the FM magnetization reversal history as well.

Progress in battery technology is closely tied to that in electronics. The fast development in battery-powered portable systems and the increasing demand for longer run time and lighter weight handheld devices is driving battery makers to make new investments and researches into new battery technologies. This resulted in a great improvement in energy density, shelf life and reliability of batteries. However the battery technology progresses are very slow compared to the ones in the electronic field. A typical battery-powered System is represented in Figure 1 [1]. This system is present in portable devices such as laptop computers, cellular phones, etc. It consists of the VLSI circuit, the dc-dc converter and the battery.

An experimental study of the mechanical properties of NiTi SMA wires and belts is carried out. The shape recovery effect and pseudoelasticity are tested. Emphasis is put on the relation between the recovery stress and testing temperature at different initial strains.Copyright © 1995 by ASME

The relationship between roughness at the Si/SiO2 interface and the oxide thickness was investigated by means of a nondestructive measuring method, using the Si metal-oxide-semiconductor (MOS) structure. It was demonstrated that the Si/SiO2 interface roughness recovers during thermal oxidation. This recovery process was also verified by observation with the transmission electron microscope (TEM). It was found that the recovery effect on the roughness at the Si/SiO2 interface depends on the oxidation process and that it is more significant in wet oxidation than in dry oxidation.

A method suitable for performing NBTI measurements on power p-channel VDMOS transistors is described. A practical implementation using simple boosting circuit for obtaining required gate stress voltage and sweep I–V measurements for the threshold voltage shift determination is presented. Experimental results are discussed in terms of the time necessary to perform interim measurements during NBTI tests. It is shown that the measurements could be done fast enough to capture part of the dynamic recovery effect in these devices, which is important for the lifetime prediction.

The recovery mechanism of the light-induced instability of amorphous InGaZnO thin-film transistors was examined. Following light illumination, the bare devices displayed more dark recovery of the threshold voltage (Vth) shifts than the ones encapsulated in nitrogen ambient. This was attributed to the adsorption of more oxygen (O2) in the back channel of the bare devices. Further, much more recovery was also observed for the bare devices than the nitrogen-encapsulated ones under positive gate bias. This implied the recovery effect under gate bias could be further enhanced because the induced electrons could greatly increase the adsorption of more O2 for the bare devices.

Using computer-aided design three-dimensional (3D) simulation technology, the recovery mechanism of single event upset and the effects of spacing and hit angle on the recovery are studied. It is found that the multi-node charge collection plays a key role in recovery and shielding the charge sharing by adding guard rings. It cannot exhibit the recovery effect. It is also indicated that the upset linear energy transfer (LET) threshold is kept constant while the recovery LET threshold increases as the spacing increases. Additionally, the effect of incident angle on recovery is analysed and it is shown that a larger angle can bring about a stronger charge sharing effect, thus strengthening the recovery ability.

For exchange bias in polycrystalline NiFe/FeMn bilayers, the hysteretic behavior of the angular dependence and the recovery effect has been studied. In particular, the pinning direction (PD) at the ending remanent state of each hysteresis loop is identified. In the hysteretic behavior, in addition to the coercivity, the PD also demonstrates different angular dependence between clockwise and counterclockwise rotations of the external magnetic field. Measurements of the recovery effect consist of two major steps. In the first step, the PD is deviated from the initial one by using its hysteretic effect and training effect. For polycrystalline NiFe/FeMn bilayers, the rotated PD is located at the maximal angle θPD0 of ±22° with respect to the initial ones. As for the second step, an external magnetic field is applied at a specific orientation θH−RE and then switched off at the same orientation. For the negative θPD0, the recovery effect only occurs for 0

The relationship between roughness at the Si/SiO2 interface and the oxide thickness was investigated by means of a nondestructive measuring method, using the Si metal-oxide-semiconductor (MOS) structure. It was demonstrated that the Si/SiO2 interface roughness recovers during thermal oxidation. This recovery process was also verified by observation with the transmission electron microscope (TEM). It was found that the recovery effect on the roughness at the Si/SiO2 interface depends on the oxidation process and that it is more significant in wet oxidation than in dry oxidation.

We have found a recovery effect from a deposit on the anode wire of proportional counters after high count detection. Usually we use a quenching gas of some organic material for proportional counters. During the development of position-sensitive proportional counters, we found that isobutylene as a quenching gas creates a deposit on the carbon anode wire in proportional counters under high irradiation, while carbon dioxide eliminates the deposit. Furthermore, we have measured the expansion of the deposit on the anode wire using an X-ray beam of 0.15 mmφ.

The hydrogen-induced charge in the hydrogenated Pd-on-GaAs (n-type) Schottky interface was observed to diminish upon application of forward current at low temperature. This apparent recovery disappears when the sample is heated towards room temperature, that is, the hydrogen-induced charge is reobserved without additional hydrogenation. Thus, it is conceivable that this apparent recovery effect is not due to the removal of the hydrogen, but to variation of the charge state of the hydrogen due to the trapping of the electrons.

The recovery effect may be induced by the introduction of a homogeneous blank flash after a patterned mask. It is not clear which parameters optimize the effect. In this study, the effect of systematical variation of the different interstimulus intervals on performance was investigated. Conditions in which the blank flash preceded the patterned mask were included. The important parameter is shown to be the interval between Mask 1 and Mask 2. For optimal recovery, this value has to be 0–20 msec. It is argued that these results, as well as a number of other recovery findings, can be explained by the suppressing influence of homogeneous flashes on contour processing channels in the visual system.

The survival of uv-irradiated phage Tl is much lower in excision repair- deficient than in excision repair-proficient E.coli cells, due to lack of host ceH reactivation (HCR). sn additional decrease in phage survival occurs when repair-deficient (HCR-) host cells have been exposed to uv doses from 3000 to 10,000 erg mm/-sup 2/ of 254 nm uv radiation prior to infection. The observed effect is attributed to loss of a minor phage recovery process, which requires neither the bacterial excision repair nor the bacterial REC repair system. This type of recovery is little affected by caffeine or acriflavine at concentrations that preclude HCR completely. Its full inhibition by uv-irradiation of the cells requires on approximately 8 times larger dose than complete inhibition of HCR. In heavily preirradiated cells, the TI burst size is extremely small and multiplicity reactivation is considerably less extensive than in unirradiated cells. Presumably the survival of singly infecting Tl in these cells reflects absence of any type of repair. The observed phage sensitivity and shape of the curve are compatible with the expectation for completely repairless conditions. The mechanism underlying the minor recovery is not known; theoretical considerations make a phage REC repair mechanism seem likely. (auth)

Processes of shape recovery by NaCl whiskers, previously deformed by bending, are studied. The studies reveal that there are two successive stages in the recovery, developing at different temperatures. A relation is established between recovery effect and the internal friction in whiskers.

Highly localized strain fields are observed at grain boundaries in crept specimens of Si3N4/MgO alloys which were frozen under stress. These fields disappear upon annealing. Unresolved asperities between the grain pairs appear to give rise to the strain field during deformation. Viscoelastic effects responsible for primary creep and strain recovery are explained in terms of grain-boundary sliding on the glassy interphase which is accommodated by the elastic strain arising at the asperities. Each boundary containing an asperity can be modelled as a simple Kelvin element. The spectrum of these boundaries within the bulk gives rise to a spectrum of relaxation times that is observed for the strain recovery effect. The highly stressed region at the asperity also gives rise to the higher chemical potential required to drive diffusional creep. Although the source of the asperities was not observed, the possibility of opposing ledges of either single or multiple interplanar height is discussed.

The stress-strain curves of Cu and Cu + Zn alloys containing alumina particles have been measured as a function of temperature, strain rate, composition, volume fraction and radius of the particles. Around room temperature the stress-strain curves of the Cu alloys are strongly temperature dependent and there is a marked recovery effect. A theory of work­ hardening is developed based on a model deduced from the electron microscope observations in which the glide dislocations generate rows of loops at the particles which act as parallel linear obstacles, leading to ‘self-hardening’ of a slip line. In addition, the interaction of other dislocations on parallel glide planes is considered, and the slip line spacing and the number of dislocations per slip line are adjusted to minimize the flow stress for a given strain. The theory predicts a parabolic stress-strain curve following an initial region of relatively low hardening rate, in good quantitative agreement with the stress-strain curves for the Cu alloys at 77 K. The predicted slip line spacing agrees with electron microscope observations. The behaviour of the Cu + Zn alloys, the temperature and strain rate dependence of the stress-strain curve, and the recovery effect are discussed qualitatively and are correlated with observed changes in the microstructure.

SummaryIn view of its importance for radiotherapy, the effects of dose fractionation have been investigated for 15 MeV neutrons and x-rays, using the reproductive capacity of cultured human cells as a criterion for survival. In the split-dose experiments either the magnitude of the second dose or the time interval between the two fractions was varied. After neutron irradiation a significant recovery effect has been observed, which is approximately a factor of two smaller than after x-irradiation.

This study investigated whether the recovery effect—obtained increments in free recall following fantasy or free associations—is producible when the stimulus is a relatively meaningless array of letters rather than a picture. Experimental Ss completed the following sequence: (a) brief (20 msec.) stimulus presentation, (b) free recall, (c) free association of letters, (d) second free recall, and (e) forced recall. Dart Control Ss completed the same sequence except for the association task, throwing darts instead. A recovery effect was obtained in postassociational free recall. The effect, however, did not survive control over response number in the forced recall measure, substantiating a response criterion interpretation of the recovery effect.

The “low-temperature” recovery range is defined as the range of temperatures in which equilibrium atomic diffusion is too slow to be the rate controlling process in recovery. A survey of various low-temperature recovery phenomena is carried out in order to determine to what extent effects due to point defects (vacancies, interstitial atoms, etc.) and to dislocations may be separated from one another. It is concluded that both annealing out of point defects and regrouping of dislocations occur in the very early stages of annealing. Of the various physical properties for which recovery data have been obtained, electrical resistivity seems to be the most sensitive to point defects, while internal friction and elastic modulus are affected most by the earliest stages of the rearrangement of dislocations. Studies of the latter properties show, in fact, that considerable dislocation recovery takes place at room temperature in very short times after deformation, even for high melting point metals. This recovery effect is believed to be the early stage of the same process that also leads to the release of stored energy and eventually to X-ray line sharpening. In the quantitative interpretation of recovery data it is convenient to regard recovery as a superposition of elementary first-order processes, each having a unique recovery time. The pre-exponential factor in the Boltzmann expression for the recovery time generally falls close to 10−11 sec. For point defect phenomena, this result implies that the mean lifetime of a defect in a cold worked lattice is of the order of 102 to 103 jumps.

A suppression-recovery (S-R) effect to repetitive light flashes has been studied in terms of evoked potentials in the optic tract in the cat under conditions of progressive light adaptation dark adaptation following bleaching, and with scotopically equated red and blue adapting fields. The S-R effect is maximal in the dark adapted eye, it parallels rod sensitivity, decreasing in duration with progressive light adaptation and increasing with rod sensitivity during recovery from bleaching. These results are discussed with respect to lateral inhibition and rod-cone interaction hypotheses.

SUMMARY Fading and recovery of Af-feulgen stained sperm heads are investigated at 73·5 K. The fast fluorescence signals are measured and stored by two coupled transient recorders. 100% recovery was reached after a dark time of 3 s. This shows that the photodecomposition is mainly caused by change of the probability density of energy level and not by destruction of the chromophore groups. The recovery effect allows measurement of the fluorescence intensity of the same sample more than 50 times. Therefore the unaffected spectrum can be measured directly, provided that between the short-term measurements at constant wavelength an appropriate dark phase has been put into operation.

The capacitive array sensor is a versatile and promising device for nondestructive evaluation of dielectric materials. The capacitive probe responds to the complex dielectric constant of the interrogated material. In the typical configuration, the device is operated as a single sided sensor. In addition to detection of surface and subsurface features in dielectric materials, the device is sensitive to surface features in conductive materials.

The period of suppression and recovery ( S-R effect) of optic tract responses which occurred at the onset of a test flash train (TFT) was also evoked by a single conditioning flash (CF) without intervening repetitive flashes. The duration of the S-R effect increased monotonically as a function of the intensity of the CF. The amplitude of the evoked potentials showing the S-R effect varied inversely with increment thresholds measured electrophysiologically during the S-R period. Thus it was possible to identify the S-R effect with similarly patterned threshold variations during rapid light adaptation in humans.

Accurate models capable to predict the dynamic behavior and the State-of-Charge (SoC) of Battery Energy Storage Systems (BESSs) is a key aspect for the definition of model-based controls in electric vehicles and in power grid applications of these energy storage systems. In this context, the paper presents an enhanced electrical BESS model capable to accurately represent the effects of charge redistribution in Lithium-based cells. In fact, this phenomenon is the main source of nonlinearity in the behavior of such devices. The improvement of the proposed model is achieved by a virtual DC current generator accounting for the internal charge transfer. The behavior of this virtual generator is inferred from experimental results describing the effects of the charge redistribution during different sub-phases, namely charge, discharge and rest phases. The proposed model, along with its parameter assessment, has been experimentally validated for: i) two types of Li-ion chemistry, ii) aged cells; iii) different cell operating temperatures ranging from -20°C up to 55°C, iv) a complex battery cell pack of 25 kWh rated energy.

Since battery life directly impacts the extent and duration of mobility, one of the key considerations in the design of a mobile embedded system should be to maximize the energy delivered by the battery, and hence the battery lifetime. To facilitate exploration of alternative implementations for a mobile embedded system, in this paper we address the issue of developing a fast and accurate battery model, and providing a framework for battery life estimation of Hardware/Software (HW/SW) embedded systems. We introduce a stochastic model of a battery, which can simultaneously model two key phenomena affecting the battery life and the amount of energy that can be delivered by the battery: the rate capacity effect and the recovery effect. We model the battery behavior mathematically in terms of parameters that can be related to physical characteristics of the electro-chemical cell. We show how this model can be used for battery life estimation of a HW/SW embedded system, by calculating battery discharge demand waveforms using a power co-estimation technique. Based on the discharge demand, the battery model estimates the battery lifetime as well as the delivered energy. Application of the battery life estimation methodology to three system implementations of an example TCP/IP network interface subsystem demonstrates that different system architectures can have significantly different delivered energy and battery lifetimes.

Very-fast high-current pulses that occur during charged device model (CDM) ESD events lead to transient voltage overshoots in forward- and reverse-biased pn-junctions, called forward recovery and dynamic reverse overshoot. To improve the device modeling for CDM circuit simulation of integrated circuits, these effects should be fully understood and should be implemented in the device models. In this paper the effects are studied under the CDM relevant operating conditions by experimental characterization and device simulation. Technological parameters have been varied to assess the presence of the effects in different technologies, such as sub-micron CMOS technologies and smart power technologies. A simple compact model extension to include the forward recovery effect in diode models is presented. A novel parameter extraction method that uses the transient TDR signals of the very-fast TLP method is introduced. Using this extraction method we can parameterize high-current device models in the nanosecond time scale. The parameter extraction method is demonstrated by applying it to the modeling of the forward recovery effect.

Wearable sensors and healthcare devices use small lightweight batteries to power their typical operations of monitoring and tracking. It becomes absolutely vital to effectively utilise all the available battery charge for device longevity between charges. The electrochemical recovery effect enables the extraction of more power from the battery when implementing idle times in between use cycles, and has been used to develop various power management techniques. However, there is no evidence concerning the actual increase in available power that can be attained using the recovery effect. Also, this property cannot be generalised on all the battery chemistries since it is an innate phenomenon, relying on the anode/cathode material. Indeed recent developments suggest that recovery effect does not exist at all. This paper presents experimental results to verify the presence and level of the recovery effect in commonly used battery chemistries in wearable sensors and healthcare devices. The results have revealed that the recovery effect significantly does exist in certain batteries, and importantly we show that it is also comprised of two different time constants. This novel finding has important implications for the development of power management techniques that utilise the recovery effect with application in a large range of battery devices.

The electrical resistivities of an α-β brass, some α brasses of various zinc contents, and an aluminium bronze have been measured after various deformations by wire drawing. The resistivity of the duplex alloy increases steeply after about 80 per cent. reduction in area. This increase is shown to be due to the resistivity change of the β phase which probably becomes disordered on deformation. A recovery effect is observed in the duplex alloy on aging at room temperature, indicating that the disordered state is not stable. No recovery has been observed in single phase wires. Unusually large increases in resistivity of some a phase alloys with deformation hare been observed and may indicate that even these alloys are not completely disordered.

A COMMUNICATION by L. L. Van Reijen1 refers to a recovery effect after an interval of some months in filed copper powder. This was shown by X-ray transmission photographs of a thin layer of the powder specimen. He used the same interval of time when verifying his observation, and presumably did not follow the progress of recovery in detail. However, in view of his reference to rotation powder photographs taken by Megaw, Lipson and Stokes2,3, in which recovery was detected some days after the preparation of the powder, it may be of interest to report that we have detected the self-recovery of filings of electrolytic tough pitch copper several days after filing, in both transmission photographs and rotation powder photographs.

The photoluminescence fatigue effect is carefully reinvestigated on a typical emission with a broad peak around 0.65 eV, believed to be associated with the main deep donor EL2, in undoped Czochralski-grown GaAs crystals. A characteristic recovery effect is found to occur in the “fatigued” emission band by continuous irradiation with Ar laser (514.5 nm); this is explained as an optical transition from the metastable state of the EL2 level to the conduction band in the configuration coordinate diagram. A wide variety of fatigue and recovery rates indicates that various lattice relaxations are induced by the microdefects responsible for the EL2 level.