Here we demonstrate electric-field induced magnetic anisotropy in a multiferroic composite containing nickel nanocrystals strain coupled to a piezoelectric substrate. This system can be switched ...between a superparamagnetic state and a single-domain ferromagnetic state at room temperature. The nanocrystals show a shift in the blocking temperature of 40 K upon electric poling. We believe this is the first example of a system where an electric field can be used to switch on and off a permanent magnetic moment.
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•EM absorbing properties of FMR-controlled M-type hexaferrite-resin composites are investigated.•The FMR frequency can be modulated in La-Co-Ti-substituted M-type Sr-hexaferrites.•The ...hexaferrite-resin composites are promising microwave and millimeter wave absorbers.
La-Co-Ti substituted Sr-hexaferrite, Sr0.906La0.094Fe11-2xCoxTixO19 (x = 0.8, 1.0, 1.2, 1.4) powder-epoxy (10 wt%) composites were fabricated for electromagnetic wave (EM) absorption application. Single M-type hexaferrite phase was confirmed by X-ray diffraction analysis for all the samples. Both saturation magnetization and coercivity of the composites decrease with increase of Co-Ti substitution x. Reflection loss (RL) of the hexaferrite powder–epoxy composites were calculated using their complex permittivity and permeability data. The EM absorbing frequency range is controlled by the substitution x because the ferromagnetic resonance (FMR) frequency of the samples is systematically varied following Snoek’s limit law. The hexaferrite sample with x = 1.2 is suitable for use as an X-band (8–12 GHz) radar absorber since RL < -10 dB is satisfied in the full X-band. Also, high EM absorbing performances in millimeter range, RL < -20 dB at 24 GHz (3 mm), and RL < -20 dB at 26.5 GHz (0.9 mm), could be achieved in the FMR-controlled La-Co-Ti substituted M-type hexaferrite-epoxy composite.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The objective of this study is to develop and validate a noncontact, nondestructive inspection and imaging method for rapidly assessing the subsurface condition of carbon fiber-reinforced polymer ...(CFRP) composite structures. The method works on the principle of planar electrical capacitance tomography (ECT). Unlike conventional ECT systems, electrodes are arranged on a rectangular planar surface in the form of a grid. The volume on one side of the electrode plane is interrogated with an electric field, and the mutual capacitances between the electrodes are measured. The volumetric electrical permittivity distribution of the interrogated region is then reconstructed from the measured capacitance responses. In this work, an ECT image reconstruction algorithm was implemented, and a customized planar capacitive imaging system was prototyped. First, different objects were placed near the electrode array, and the corresponding volumetric change in electrical permittivity was successfully captured. Second, the planar ECT system was employed for detecting artificially introduced subsurface defects in 3D-printed objects. Third, CFRP specimens with different sizes of single-layer delamination were fabricated and subjected to ECT interrogation. The results confirmed that the planar ECT system could detect the location and size of delamination in CFRP panels. The accuracy and resolution of the planar ECT prototype were also characterized.
Anti-ferroelectric (PbLa)(ZrTi)O
3
(PLZT) is a promising material for use in multilayer ceramic capacitors (MLCCs) for electric vehicles, as its dielectric and polarization properties are enhanced ...under high electric fields. To facilitate the commercialization of Cu-MLCCs, sintering in a reduction atmosphere is necessary. In this study, the effect of adding Mn ions in varying concentrations (ranging from a small amount to an excess of 2.0 mol.%, 3.0 mol.%, 5.0 mol.%, 10.0 mol.%, and 20.0 mol.%) on the dielectric constant and breakdown voltage was investigated to understand their behavior under high electric fields. Regardless of the amount of Mn ions added, a single perovskite structure with no secondary phase was observed. These oxygen vacancies originated from the ions occupying the B-site in the perovskite structure, thereby influencing the dielectric properties and breakdown voltage. Interestingly, the breakdown voltage improved significantly, reaching up to 8.0 kV/mm, and no phase transition to the ferroelectric state occurred, regardless of the amount of Mn ions substituted. Overall, it was evident that the anti-ferroelectric properties of PLZT were well maintained.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Estimation of the local attenuation coefficient in soft tissue is important both for clinical diagnosis and for further analysis of ultrasound B-mode images. However, it is difficult to extract ...spectral properties in a small region of interest from noisy backscattered ultrasound radio frequency (RF) signals. Diffraction effects due to transducer beam focal properties also have to be corrected for accurate estimation of the attenuation coefficient. In this paper, we propose a new attenuation estimation method using spectral cross-correlation between consecutive power spectra obtained from the backscattered RF signals at different depths. Since the spectral cross-correlation method estimates the spectral shift by comparing the entire power spectra, it is more robust and stable to the spectral noise artifacts in the backscattered RF signals. A diffraction compensation technique using a reference phantom with a known attenuation coefficient value is also presented. Local attenuation coefficient estimates obtained using spectral cross-correlation are within 2.3% of the actual value with small estimation variances, as demonstrated in the simulation results
Hypertriglyceridemia (HTG) is a state of increased serum triglyceride (TG) affected by multigenetic and multifactorial causes. Serum TG concentration can be markedly elevated if exposed to ...precipitating factors, such as estrogen hormone and pregnancy. We report the case of a patient with severe HTG who suffered from recurrent pancreatitis during the second trimester of pregnancy conceived with in vitro fertilization-embryo transfer (IVF-ET) and was successfully controlled by multiple sessions of plasmapheresis.A 24-year-old pregnant woman was admitted because of a sudden onset of severe abdominal pain at 26 weeks of gestation conceived by IVF-ET. She has experienced recurrent pancreatitis despite low-fat diet and dyslipidemia medications allowed in pregnancy. At admission, serum amylase and lipase were elevated to 347 and 627 U/L, respectively, along with fasting TG to 4809 mg/dL. A clinical diagnosis of HTG-induced acute pancreatitis was made, and plasmapheresis was performed. After plasmapheresis, serum TG, amylase, and lipase levels decreased to 556 mg/dL, 60 U/L, and 69 U/L, respectively, along with subsequent pain relief. The patient underwent a total of nine sessions of plasmapheresis to retain serum TG lower than 1,000 mg/dL during pregnancy, with no further recurrence of acute pancreatitis. After delivery, the serum TG level was maintained below 500 mg/dL with a combination treatment of fenofibrate, statin, and ezetimibe.Although severe HTG is usually asymptomatic, if exposed to precipitating factors, it can cause acute pancreatitis, a fatal complication. Early application of plasmapheresis may be a useful option in HTG-induced acute pancreatitis intractable to medical treatment; however, its indications, risks, and benefits should be carefully evaluated.
The human clavicle’s unique S-shaped, three-dimensional structure complicates fracture management. This study evaluated the anatomical conformity of pre-contoured anatomical plates using 3D-printed ...clavicle models. CT scans from 30 patients (15 males and 15 females) were used to create these models. Three brands of distal clavicle plate systems (Acumed, Synthes, and Arthrex) were tested for fit. Measurements included the distance from the distal end of the clavicle to the plate’s lateral end, the gap between the clavicle and the plate, and the overhang distance. Results showed significant differences in clavicle length between sexes, with men having a mean length of 156.1 ± 7.6 mm and women 138.4 ± 4.3 mm, both with normal distribution (p > 0.05). The mean lateral distance was 7.9 ± 1.7 mm, and the mean medial gap was 3.6 ± 3.0 mm, showing no significant differences between products or sexes. The mean overhang distance was 5.8 ± 4.6 mm, with larger values in women for the Acumed (p = 0.037) and Arthrex (p = 0.000) plates. Overall, pre-contoured plates exhibited notable discrepancies, especially in shorter clavicles.
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An essential requirement for bio/chemical sensors and electronic nose systems is the ability to detect the intended target at room temperature with high selectivity. We report a reduced graphene ...oxide (rGO)-based gas sensor functionalized with a peptide receptor to detect dinitrotoluene (DNT), which is a byproduct of trinitrotoluene (TNT). We fabricated the multi-arrayed rGO sensor using spin coating and a standard microfabrication technique. Subsequently, the rGO was subjected to photolithography and an etching process, after which we prepared the DNT-specific binding peptide (DNT-bp, sequence: His-Pro-Asn-Phe-Se r-Lys-Tyr-IleLeu-HisGln-Arg-Cys) and DNT non-specific binding peptide (DNT-nbp, sequence: Thr-Ser-Met-Leu-Leu-Met-Ser-Pro-Lys-His-Gln-Ala-Cys). These two peptides were prepared to function as highly specific and highly non-specific (for the control experiment) peptide receptors, respectively. By detecting the differential signals between the DNT-bp and DNT-nbp functionalized rGO sensor, we demonstrated the ability of 2,4-dinitrotoluene (DNT) targets to bind to DNT-specific binding peptide surfaces, showing good sensitivity and selectivity. The advantage of using the differential signal is that it eliminates unwanted electrical noise and/or environmental effects. We achieved sensitivity of 27 ± 2 × 10
per part per billion (ppb) for the slope of resistance change versus DNT gas concentration of 80, 160, 240, 320, and 480 ppm, respectively. By sequentially flowing DNT vapor (320 ppb), acetone (100 ppm), toluene (1 ppm), and ethanol (100 ppm) onto the rGO sensors, the change in the signal of rGO in the presence of DNT gas is 6400 × 10
per ppb whereas the signals from the other gases show no changes, representing highly selective performance. Using this platform, we were also able to regenerate the surface by simply purging with N
.
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This paper discusses a non-destructive evaluation (NDE) technique for the detection of damage in composite aircraft structures following high energy wide area blunt impact (HEWABI) from ground ...service equipment (GSE), such as heavy cargo loaders and other heavy equipment. The test structures typically include skin, co-cured stringers, and C-frames that are bolt-connected onto the skin with shear ties. The inspection exploits the waveguide geometry of these structures by utilizing ultrasonic guided waves and a line scan approach. Both a contact prototype and a non-contact prototype were developed and tested on realistic test panels subjected to impact in the laboratory. The results are presented in terms of receiver operating characteristic curves that show excellent probability of detection with low false alarm rates for defects located in the panel skin and stringers.
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Previous studies on the immunogenicity of blood group antigens have utilized a formula incorporating antigen frequencies and relative frequencies of unexpected antibodies to the corresponding ...antigens. This study was aimed at investigating other variables potentially affecting the estimation of immunogenicity using this formula. We examined the effect of multiple transfusions, as there are more chance for a recipient to receive repeated transfusions rather than only once; the effect of antigen density, which may vary depending on homozygote/heterozygote; and the effect of unreliability of the observed frequency of rare antibodies and antigens. For multiple transfusions, the expected antibody frequency increased as the number of transfusions increased. For antigen density, the immunogenicity was falsely low for the low-prevalence antigen, and this tendency intensified as the effect of antigen density increased. Expected antibody frequencies were significantly affected by the uncertainties caused by estimation of small numbers. This study showed that the effects of various factors on the immunogenicity of blood group antigens depended on the antigen frequency. Estimating the immunogenicity of blood group antigens requires acknowledging the diverse factors that can affect it and interpreting the findings with caution.
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