Mid-range Region Research Articles

Auto-Tracking Time Reversal Wireless Power Transfer System With a Low-Profile Planar RF-Channel Cascaded Transmitter

In order to continuously power movable sensors, we present an autotracking continuous-wave time reversal (TR) wireless power transfer (ACTR-WPT) system of a novel low-profile planar transmitter. The new transmitter is designed with a radio-frequency (RF)–channel cascaded structure, which couples only a little energy of the amplified feeding signal of each radiating element to the following cascaded one. Such RF-channel cascaded transmitter makes the decrease or increase of the number of the radiating elements quite flexible. The transmitting circuits are highly integrated with a microstrip antenna for every radiating element, which benefits the planar transmitter with the profile of less than 3 mm and the weight of each radiating element of less than 40g. Meanwhile, we develop an autotracking algorithm for the ACTR-WPT system, which inherently depends on the adaptive focusing mechanism of the TR technique. With the newly developed autotracking algorithm, we successfully demonstrate the experiments of powering the devices arbitrarily moving within a range from 1m to 7 m and the angle from -45° to +45°. The received dc power ranges from 1mW to 250 mW. The demonstration results are exciting for applications in charging or powering the movable sensors of low power consumption within a mid-range region.

Data imputation in in situ-measured particle size distributions by means of neural networks

Abstract. In air quality research, often only size-integrated particle mass concentrations as indicators of aerosol particles are considered. However, the mass concentrations do not provide sufficient information to convey the full story of fractionated size distribution, in which the particles of different diameters (Dp) are able to deposit differently on respiratory system and cause various harm. Aerosol size distribution measurements rely on a variety of techniques to classify the aerosol size and measure the size distribution. From the raw data the ambient size distribution is determined utilising a suite of inversion algorithms. However, the inversion problem is quite often ill-posed and challenging to solve. Due to the instrumental insufficiency and inversion limitations, imputation methods for fractionated particle size distribution are of great significance to fill the missing gaps or negative values. The study at hand involves a merged particle size distribution, from a scanning mobility particle sizer (NanoSMPS) and an optical particle sizer (OPS) covering the aerosol size distributions from 0.01 to 0.42 µm (electrical mobility equivalent size) and 0.3 to 10 µm (optical equivalent size) and meteorological parameters collected at an urban background region in Amman, Jordan, in the period of 1 August 2016–31 July 2017. We develop and evaluate feed-forward neural network (FFNN) approaches to estimate number concentrations at particular size bin with (1) meteorological parameters, (2) number concentration at other size bins and (3) both of the above as input variables. Two layers with 10–15 neurons are found to be the optimal option. Worse performance is observed at the lower edge (0.01<Dp<0.02 µm), the mid-range region (0.15<Dp<0.5 µm) and the upper edge (6<Dp<10 µm). For the edges at both ends, the number of neighbouring size bins is limited, and the detection efficiency by the corresponding instruments is lower compared to the other size bins. A distinct performance drop over the overlapping mid-range region is due to the deficiency of a merging algorithm. Another plausible reason for the poorer performance for finer particles is that they are more effectively removed from the atmosphere compared to the coarser particles so that the relationships between the input variables and the small particles are more dynamic. An observable overestimation is also found in the early morning for ultrafine particles followed by a distinct underestimation before midday. In the winter, due to a possible sensor drift and interference artefacts, the estimation performance is not as good as the other seasons. The FFNN approach by meteorological parameters using 5 min data (R2= 0.22–0.58) shows poorer results than data with longer time resolution (R2= 0.66–0.77). The FFNN approach using the number concentration at the other size bins can serve as an alternative way to replace negative numbers in the size distribution raw dataset thanks to its high accuracy and reliability (R2= 0.97–1). This negative-number filling approach can maintain a symmetric distribution of errors and complement the existing ill-posed built-in algorithm in particle sizer instruments.

Comparative analysis of the functional results after implantation of various diffractive trifocal intraocular lenses

To compare visual outcomes after implantation of two models of diffractive trifocal IOLs using various vision assessment systems. The study included 25 patients (25 eyes) who were implanted with AcrySof IQ PanOptix (TFN) and 25 patients (25 eyes) implanted with AT LISA tri 839 MP (TRI). Postoperative examination at 1 year included assessment of monocular visual acuity for far, intermediate and near distance using decimal scale, as well as LogMAR and an interactive computer program (ICP). Contrast sensitivity was assessed with the Optec 6500 device. A questionnaire was used to evaluate subjective quality of vision and the intensity of optical phenomena. Uncorrected visual acuity (UCVA) at distance, intermediate and near was better in the TFN group in comparison with the TRI group as measured with decimal scale, ICP and LogMAR. Under photopic and mesopic conditions with and without glare, at all spatial frequencies the contrast sensitivity function (CSF) was higher after implantation of TFN in comparison with TRI. The average VF-14 score was 97.2 after implantation of TFN and 96.7 after implantation of TRI. The amount of patients who required spectacle correction after the surgery was 5.5% less in the TFN group compared to the TRI group. High visual outcomes at all distances were observed in patients after implantation of both trifocal IOLs with TFN showing a slight advantage. Evaluation of the visual outcomes using various systems showed the benefits of the ICP assessment. The CSF had typical configuration with maximum value in the mid-range region and a decrease in the high-frequency range after implantation of both IOLs, however the indicators were better in the TFN group. The postoperative period was characterized by high levels of patient satisfaction and spectacle independence in both groups.

Modeling the impact of radiation-enhanced diffusion on implanted ion profiles

Ion irradiations are a valuable research tool for exploring radiation effects in materials. However, it is well recognized that the implanted ions can artificially modify the radiation damage evolution, e.g., enhancing amorphization processes at low irradiation temperatures and suppressing void swelling at elevated temperatures. Therefore, the implanted ion region should be avoided for most studies of ion irradiated materials. Due to increased interest in high damage, high temperature ion irradiations studying radiation effects in materials for proposed high dose Generation IV fission and fusion energy applications, it is crucial to quantify the extent of diffusional broadening of the implanted ion profile for a variety of temperatures, irradiation fluxes, and sink strengths. The present study summarizes computational analyses of thermal and depth-dependent radiation enhanced diffusion (RED) on diffusion broadening of the implanted ion profiles in Fe and Ni for a variety of irradiation conditions. For a low assumed RED coefficient (10−20-10−19 m2/s and 10−4 and 10−3 peak dpa/s, respectively) or high flux, broadening of the as-implanted ion profile is very small and a suitable artifact-free midrange region for analysis exists for ion energies above 5–6 MeV at 100 peak dpa. At high RED coefficients (10−19-10−18 m2/s and 10−4 and 10−3 peak dpa/s, respectively) broadening is much more significant, and no valid region for investigation exists below 6–8 MeV ion energies at any damage level >50 dpa. While increasing flux decreases irradiation time, it also increases the RED coefficient; these effects mostly offset except under recombination-dominant conditions. For typical high dose irradiation studies of void swelling that exceed ∼100 displacement per atom (dpa), ion energies >6–8 MeV must be employed in order to achieve suitable artifact-free midrange irradiation analysis regions, depending on the material system. Analysis of amorphization/precipitation require even higher energies (>10 MeV).

Анализ функциональных результатов имплантации новой модели трифокальной интраокулярной линзы

Today, patients often expect to achieve a high visual acuity at various distances and a spectacle correction independence after cataract surgery. Trifocal intraocular lenses have been developed to try and fulfill this demand. Due to the lack of domestic experience with the new trifocal IOL model (AcrySof® IQ PanOptix®), there is a need for clinical trials to evaluate functional outcomes. Purpose. To evaluate outcomes of visual acuity using various traditional systems of assessment for functional vision and interactive computer program in a comparative aspect, as well as a contrast sensitivity and to determine a subjective patient satisfaction after implantation of a new generation of trifocal IOL AcrySof IQ PanOptix (USA). Material and methods. The study included 19 patients (37 eyes) with cataract. Mean age was 55.6±11.4 years. Visual acuity was measured monocular using different technics at distance (4 m), intermediate (60 cm) and near (40 cm). The Optec 6500 device was used for objective assessment of contrast sensitivity function. The frequency of dysphotopsia and quality of vision were evaluated by the questionnaire. Results. High visual activity results at different distances with the decimal scale and interactive computer program «TIP-TOP» were noted on the 1st day after implantation of the new trifocal IOL model. Improvement of visual acuity at three distances 3-6 months after surgery was associated with a stabilization of refractive results and a completion of neuro-adaptation processes. Mean postoperative spherical equivalent was -0.40±0.34D 1 month postoperatively and -0.28±0.27D 6 months after surgery, respectively. The contrast sensitivity function (CSF) had a typical appearance with a maximum value in the mid-range region and a decrease in the high-frequency range. The levels of photopic and mesopic CS with and without glare increased within 6 months after the operation. Mean value of VF-14 was 95.7, indicating a high level of subjective assessment of intraocular correction. No patient noted a need to use any spectacle correction for far, near or intermediate distances after surgery. More often dysphotopsia was detected through active patient interview. In dynamics, the degree of dysphotopsia decreased, or completely disappeared in 33.3% of patients 6 months after the operation. Conclusions. The new trifocal IOL provides good near, intermediate and far distance visual functions. Evaluation of visual acuity results using different systems showed the advantage of the interactive computer program Tip-Top. The contrast sensitivity function (CSF) had a typical appearance with a maximum value in the mid-range region and a decrease in the highfrequency range. The indicators of photopic and mesopic CS with and without glare increased within 6 months after the operation, however, they did not reach the age standards. Postoperative period was characterized by a high patient satisfaction and a high spectacle correction independence.

High Performance Flexible Actuator of Urchin-Like ZnO Nanostructure/Polyvinylenefluoride Hybrid Thin Film with Graphene Electrodes for Acoustic Generator and Analyzer.

A bass frequency response enhanced flexible polyvinylidene fluoride (PVDF) based thin film acoustic actuator is successfully fabricated. High concentrations of various zinc oxide (ZnO) is embedded in PVDF matrix, enhancing the β phase content and the dielectric property of the composite thin film. ZnO acts as a nucleation agent for the crystallization of PVDF. A chemical vapor deposition grown graphene is used as electrodes, enabling high electron mobility for the distortion free acoustic signals. The frequency response of the fabricated acoustic actuator is studied as a function of the film thickness and filler content. The optimized film has a thickness of 80 μm with 30 wt% filler content and shows 72% and 42% frequency response enhancement in bass and midrange compared to the commercial PVDF, respectively. Also, the total harmonic distortion decreases to 82% and 74% in the bass and midrange regions, respectively. Furthermore, the composite film shows a promising potential for microphone applications. Most of all, it is demonstrated that acoustic actuator performance is strongly influenced by degree of PVDF crystalline.

Exploring the Relationship between Family Functioning and Psycho-Pathology in a Sample in the Pediatric Age.

The purpose of this study was to investigate differences in family functioning between families with clinical subjects in paediatric age and families taken from the Italian population. To this aim we used the Family Adaptability and Cohesion Evaluation Scale (FACES). Participants were children diagnosed with a psychopathology, recruited into the psychiatry department in a Paediatric Hospital of Rome. A total of 106 families participated in the study. The non-pathological sample is composed by 2,543 parents in different age periods of the life-cycle. Results showed significant differences in family functioning between pathological and non-pathological samples. Specifically, families from the pathological sample (particularly the ones who experienced eating disorders) were more frequently located in extreme or mid-range regions of Olson's circumplex model (p < .001). These findings suggest some considerations that can be useful in therapeutic works with families in a clinical setting. Critical aspects and clinical applications are discussed.

Vibrational Energy Relaxation of Liquid Aryl-Halides X-C6H5 (X = F, Cl, Br, I)

Anti-Stokes Raman spectroscopy was used to probe vibrational energy dynamics in liquid ambient-temperature aryl-halides, X-Ph (X = F, Cl, Br, I; -Ph = C(6)H(5)), following IR excitation of a 3068 cm(-1) CH-stretching transition. Five ring vibrations and two substituent-dependent vibrations were monitored in each aryl-halide. Overall, the vibrational relaxation (VR) lifetimes in aryl-halides were shorter than those in normal benzene (H-Ph). The aryl-halide CH-stretch lifetimes increased in the order F, Cl, Br, I, ranging from 2.5 to 3.4 ps, compared with 6.2 ps in H-Ph. The aryl-halide energy transfer processes were similar overall with four exceptions. Three of the four exceptions could be explained as a result of faster VR of midrange vibrations (1000-1600 cm(-1)) in the heavier aryl-halides. The fourth appeared to result from a coincidental resonance in chlorobenzene that does not occur in the other aryl-halides. Among the aryl-halides, the decay of CH-stretching excitations (∼3070 cm(-1)) was slower in the heavier species, but the decay of midrange vibrations was faster in the heavier species. This seeming contradiction could be explained if VR depended primarily on the density of states (DOS) of the lower tiers of vibrational excitations. The DOS for the first few (1-4) tiers is similar for all aryl-halides in the CH-stretch region, but DOS increases with increasing halide mass in the midrange region.

The Effect of Material Heterogeneity and Random Loading on the Mechanics of Fatigue Crack Growth

This paper reviews the experimental work on the influence of variable amplitude or random loads on the mechanics and micromechanisms of fatigue crack growth. Implications are discussed in terms of the crack driving force, local plasticity, crack closure, crack blunting, and microstructure. Due to heterogeneity in the material’s microstructure, the crack growth rate varies with crack tip position. Using the weakest link theory, an expression for crack growth rate is obtained as the expectation of a random variable. This expression is used to predict the crack growth rates for aluminum alloys, a titanium alloy, and a nickel steel in the midrange region. It is observed using the present theory that the crack growth rate obeys the power law for small ΔK and that the power is a function of a material constant.

On the modeling of irradiation-induced homogeneous precipitation in proton-bombarded Ni-Si solid solutions

Abstract Irradiation-induced solute redistribution leading to precipitation of coherent γ' particles in undersaturated Ni-based solid solutions containing 6 and 8 at.% Si during 400-keV proton bombardment was modeled, based on the concept of solute segregation in concentrated alloys under spatially-dependent defect production conditions. The combined effects of (i) an extremely large difference between the defect production rates in the peak-damage and mid-range regions during irradiation and (ii) a preferential coupling between the interstitial and solute fluxes generate a net transient flux of Si atoms into the mid-range region, which is much larger than the solute flux out of this location. As a result, the Si concentration exceeds the solubility limit and homogeneous precipitation of the γ' phase occurs in this particular region of the irradiated samples. The spatial, compositional and temperature dependences of irradiation-induced homogeneous precipitation derived from the present theoretical calculations are in good qualitative agreement with experimental observations