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Based on the polynomial theory, the error propagation characteristics of the widely used N-step discrete Fourier transform (N-DFT) phase-shift algorithm were analyzed via theoretical analysis, under the effect of Gamma distortion and phase detuning. The results showed that the N-DFT algorithm could not simultaneously suppress both types of error. A robust linear phase-shift (RLPS) algorithm was designed, the performance of the RLPS and 8-DFT algorithms in terms of spectral response, detuning robustness, and G S / N was briefly analysis by Manuel Servin method. The Simulation analysis and comparison of the results show that the RLPS algorithm could suppress both types of error simultaneously, which exhibited better stability and accuracy than N-DFT and exponential algorithms, particularly in gradient measurement stability, peak-to-valley (PV) and root-mean-square (RMS) error suppression. Moreover, a physical experiment apparatus was built to test unidirectionally inclined plane mirror and concave mirror using the RLPS, N-DFT, and exponential algorithms. The results showed that the RLPS algorithm could significantly improve the measurement stability and accuracy in the presence of detuning and without screen Gamma calibration.
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The classical body ownership illusion, such as the rubber hand illusion, is achieved through appropriate proprioceptive displacement within temporal and spatial constraints that do not exceed the limits of proprioceptive flexibility. In the 2023 Best Illusion of the Year Contest, we introduced Buddha's ear illusion (BEI), which creates the illusion of owning a dramatically deformed earlobe through immediate visuotactile stimulation and seemingly challenges classical proprioceptive boundaries. The laboratory experiment examined the mechanics of this illusion, revealing a significant interaction between tactile earlobe pulling and visual miming that contributed to the enhanced perception of earlobe stretch. Importantly, 88% of the participants confirmed the illusory earlobe stretch (a rating of +4 or higher on a 7-point scale). More than half reported an earlobe descent of >10 cm within a 10-s visuotactile stimulation. The findings suggest that BEI operates on a distinct principle separate from proprioceptive modulation in contrast to classical ownership illusions.
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BACKGROUND: Geometric distortion is a serious problem in MRI, particularly in MRI guided therapy. A lack of affordable and adaptable tools in this area limits research progress and harmonized quality assurance. PURPOSE: To develop and test a suite of open-source hardware and software tools for the measurement, characterization, reporting, and correction of geometric distortion in MRI. METHODS: An open-source python library was developed, comprising modules for parametric phantom design, data processing, spherical harmonics, distortion correction, and interactive reporting. The code was used to design and manufacture a distortion phantom consisting of 618 oil filled markers covering a sphere of radius 150 mm. This phantom was imaged on a CT scanner and a novel split-bore 1.0 T MRI magnet. The CT images provide distortion-free dataset. These data were used to test all modules of the open-source software. RESULTS: All markers were successfully extracted from all images. The distorted MRI markers were mapped to undistorted CT data using an iterative search approach. Spherical harmonics reconstructed the fitted gradient data to 1.0 ± 0.6% of the input data. High resolution data were reconstructed via spherical harmonics and used to generate an interactive report. Finally, distortion correction on an independent data set reduced distortion inside the DSV from 5.5 ± 3.1 to 1.6 ± 0.8 mm. CONCLUSION: Open-source hardware and software for the measurement, characterization, reporting, and correction of geometric distortion in MRI have been developed. The utility of these tools has been demonstrated via their application on a novel 1.0 T split bore magnet.
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The primary goal of the presented research was to investigate how processing post-event information affects memory of details in an event viewed on video. We used two forms of post-event information: classic misinformation (changing or implanting new information into memory) and a new form that involves a correct explicit or implicit negation of the existence of an object in the video. We followed the three-step procedure used in studies on the misinformation effect, with a final memory test that was either immediate or delayed by a week and consisted in indicating which objects appeared in the video. We replicated the misinformation effect. More importantly, in the delayed test condition, both explicitly and implicitly negated objects were falsely recalled more often than unmentioned objects. These results indicate that it is possible to induce negation-related false memories; they also show that memory is impaired by negated post-event information or misleading post-event information.
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The present article addresses claims commonly made by prosecution witnesses in sexual assault trials: that attention narrows under stress, and that these attended aspects of the event are encoded in a way that ensures accuracy and resistance to fading and distortion. We provide evidence to contradict such claims. Given that what is encoded is largely the gist of one's interpretation of experience, we discuss the way in which attention and emotion can bias the interpretation of experience. We illustrate with issues of memory reports in cases of acquaintance rape, where the primary issue is the presence or absence of consent. We provide some specific illustrations concerning effects of emotion on interpretation of sexual consent. Finally, based on what is known regarding priming effects on memory retrieval and judgment, we conclude with discussion of the potential of some "trauma-informed" interviewing strategies to promote false memories (such as FETI: Forensic Experiential Trauma Interview).
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Introduction: SMART syndrome is a rare complication of brain radiotherapy. This is the first described presentation of SMART syndrome with metamorphopsia, which responded to aspirin, verapamil, and high-dose L-arginine therapy. Case Presentation: A 43-year-old man presented with 3 weeks of migraine headaches with metamorphopsia and complex visual hallucinations affecting the left lower quadrant of both visual fields. This occurred on a background of high-dose radiotherapy for right cerebellar astrocytoma 32 years ago. MRI brain demonstrated unilateral gyriform enhancement and FLAIR hyperintense cortical swelling in the right occipital lobe consistent with SMART syndrome. Conclusion: Unusual presentations of SMART syndrome exist and require consideration in all patients with focal neurological deficit post-brain radiotherapy. Validated diagnostic and treatment modalities for SMART syndrome are urgently required.
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Low dimensional organic-inorganic hybrid metal halide materials have attracted extensive attention due to their superior optoelectronic properties. However, low photoluminescence quantum yields (PLQYs) caused by parity-forbidden transition hinder their further application in optoelectronic devices. Herein, a novel yellow-emitting PMA4Na(In,Sb)Cl8 (C7H10N+, PMA+) low-dimensional OIMHs single crystal with a PLQY as high as 88% was successfully designed and synthesized, originating from the fact that the doping of Sb3+ effectively relaxes the parity-forbidden transition by strong spin-orbit (SO) coupling and Jahn-Teller (JT) interaction. The as-prepared crystal shows an efficient dual emission peaking 495 and 560 nm at low temperature, which are ascribed to different levels of 3P1 â 1S0 transitions of Sb3+ in [SbCl6]3- octahedral caused by JT deformation. Moreover, wide-range luminescence tailoring from cyan to orange can be achieved through adjusting excitation energy and temperature because of flexible [SbCl6]3- octahedral in the PNIC lattice. Based on a relative stiff lattice environment, the 560 nm yellow emission under 350 nm light excitation exhibits abnormal anti-thermal quenching from 8 to 400 K owing to the suppression of non-radiative transition. The multimode luminescence regulation enriches PMA4Na(In,Sb)Cl8 great potential in the field of optoelectronics such as temperature sensing, low temperature anti-counterfeiting and WLED applications.
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A lightning current measurement method using a Rogowski coil based on an integral circuit with low-frequency attenuation feedback was proposed to address the issue of low-frequency distortion in the measurement of lightning currents on transmission lines using Rogowski coils. Firstly, the causes of low-frequency distortion in lightning current measurements using Rogowski coils were analyzed from the perspective of frequency domains. On this basis, an integration correction optimization circuit with a low-frequency attenuation feedback network was designed to correct the low-frequency distortion. The optimized integration circuit can also reduce the impact of low-frequency noise and the DC bias of the operational amplifier (op-amp) on the integration circuit due to the high low-frequency gain. Additionally, a high-pass filtering and voltage-divided sampling circuit has been added to ensure the normal operation of the integrator and improve the measurement range of the measurement system. Then, according to the relationship between the amplitude-frequency characteristics of the measurement system and the parameters of each component, the appropriate types of components and op-amp were selected to expand the measurement bandwidth. Finally, a simulation verification was conducted, and the simulation results show that this measurement method can effectively expand the lower measurement frequency limit to 20 Hz, correct the low-frequency distortion caused by Rogowski coils measuring lightning currents on transmission lines, and accurately restore the measured lightning current waveform.
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Fiber orientation distributions (FODs) is a popular model to represent the diffusion MRI (dMRI) data. However, imaging artifacts such as susceptibility-induced distortion in dMRI can cause signal loss and lead to the corrupted reconstruction of FODs, which prohibits successful fiber tracking and connectivity analysis in affected brain regions such as the brain stem. Generative models, such as the diffusion models, have been successfully applied in various image restoration tasks. However, their application on FOD images poses unique challenges since FODs are 4-dimensional data represented by spherical harmonics (SPHARM) with the 4-th dimension exhibiting order-related dependency. In this paper, we propose a novel diffusion model for FOD restoration that can recover the signal loss caused by distortion artifacts. We use volume-order encoding to enhance the ability of the diffusion model to generate individual FOD volumes at all SPHARM orders. Moreover, we add cross-attention features extracted across all SPHARM orders in generating every individual FOD volume to capture the order-related dependency across FOD volumes. We also condition the diffusion model with low-distortion FODs surrounding high-distortion areas to maintain the geometric coherence of the generated FODs. We trained and tested our model using data from the UK Biobank (n = 1315). On a test set with ground truth (n = 43), we demonstrate the high accuracy of the generated FODs in terms of root mean square errors of FOD volumes and angular errors of FOD peaks. We also apply our method to a test set with large distortion in the brain stem area (n = 1172) and demonstrate the efficacy of our method in restoring the FOD integrity and, hence, greatly improving tractography performance in affected brain regions.
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The structural failure of Na2Mn[Fe(CN)6] could not be alleviated with traditional modification strategies through the adjustable composition property of Prussian blue analogues (PBAs), considering that the accumulation and release of stress derived from the MnN6 octahedrons are unilaterally restrained. Herein, a novel application of adjustable composition property, through constructing a coordination competition relationship between chelators and [Fe(CN)6]4- to directionally tune the enrichment of elements, is proposed to restrain structural degradation and induce unconventional energy coupling phenomenon. The non-uniform distribution of elements at the M1 site of PBAs (NFM-PB) is manipulated by the sequentially precipitated Ni, Fe, and Mn according to the Irving-William order. Electrochemically active Fe is operated to accompany Mn, and zero-strain Ni is modulated to enrich at the surface, synergistically mitigating with the enrichment and release of stress and then significantly improving the structural stability. Furthermore, unconventional energy coupling effect, a fusion of the electrochemical behavior between FeLS and MnHS, is triggered by the confined element distribution, leading to the enhanced electrochemical stability and anti-polarization ability. Consequently, the NFM-PB demonstrates superior rate performance and cycling stability. These findings further exploit potentialities of the adjustable composition property and provide new insights into the component design engineering for advanced PBAs.
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Uncovering the hardening mechanisms is of great importance to accelerate the design of superhard high-entropy carbides (HECs). Herein, the hardening mechanisms of HECs by a combination of experiments and first-principles calculations are systematically explored. The equiatomic single-phase 4- to 8-cation HECs (4-8HECs) are successfully fabricated by the two-step approach involving ultrafast high-temperature synthesis and hot-press sintering techniques. The as-fabricated 4-8HEC samples possess fully dense microstructures (relative densities of up to ≈99%), similar grain sizes, clean grain boundaries, and uniform compositions. With the elimination of these morphological properties, the monotonic enhancement of Vickers hardness and nanohardness of the as-fabricated 4-8HEC samples is found to be driven by the aggravation of lattice distortion. Further studies show no evident association between the enhanced hardness of the as-fabricated 4-8HEC samples and other potential indicators, including bond strength, valence electron concentration, electronegativity mismatch, and metallic states. The work unveils the underlying hardening mechanisms of HECs and offers an effective strategy for designing superhard HECs.
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The purpose of this study was to develop two pictorial tools for assessing the attitudes of Taiwanese male senior high school students with intellectual disabilities toward sexually offensive behavior, focusing on cognitive distortion and victim empathy. A total of 181 male high school students at special education schools participated in this study. The validity and reliability were examined using exploratory factor analysis and Cronbach's alpha coefficient. For the cognitive distortion scale, 18 items grouped into three factors, rationalization, denial, and victim blaming, and explained 69.72% of the variance; for the victim empathy scale, 12 items grouped into two factors, the victim's feelings when the offensive behavior is perpetrated by another, and the victim's feelings when the offensive behavior is perpetrated by oneself, and explained 68.00% of the variance. The reliability was .96 for the cognitive distortion scale and .93 for the victim empathy scale. In conclusion, the two scales developed in this research were found to be reliable and valid tools for evaluating male students' attitudes toward sexually offensive behavior, and can also be used as reference material for courses in sex education.
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Body image distortion (BID) is a crucial aspect of anorexia nervosa (AN), leading to body overestimation, dissatisfaction, and low self-esteem. BID significantly influences the onset, maintenance, and relapse of the pathology. We assessed whether a Full Body Illusion (FBI) using under and normal-weight avatars' bodies affects perceptual body image and body schema estimations in both individuals with anorexia nervosa (AN) and healthy controls (HC). After each embodiment procedure, we asked participants to estimate the width of their hips (Perceptual Body Image Task) and the minimum aperture width of a virtual door necessary to pass through it (Body Schema Task). Additionally, we asked participants to rate the avatars in terms of self-similarity, attractiveness, and implicit disgust (i.e., pleasant/unpleasant body odour). Whereas participants with AN (N = 26) showed changes in body schema estimations after embodying the normal-weight avatar, no changes were found in HC (N = 25), highlighting increased bodily self-plasticity in AN. Notably, individuals with AN rated the normal weight avatar as the most similar to their real body, which was also considered the least attractive and the most repulsive. These ratings correlated with BID severity. Furthermore, at the explicit level, all participants reported feeling thinner than usual after embodying the underweight avatar. Overall, our findings suggest that BID in AN engages multiple sensory channels (from visual to olfactory) and components (from perceptual to affective), offering potential targets for innovative non-invasive treatments aimed at modifying flexible aspects of body representation.
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Multiprincipal element alloys usually exhibit earlier pop-in events than pure metals and dilute solid solutions during nanoindentation experiments. To understand the origin of this phenomenon, large-scale atomic simulations of nanoindentation were performed on a series of metallic materials to investigate the underlying physics of incipient plasticity at the nanoscale. Statistical result shows that lattice distortion δ and normalized critical pressure pc/Es follow a power-law relationship. Via quantitative analysis on the relative positions of the atoms within the nearest neighbor shell, the physical origin of premature incipient plasticity is revealed as severe lattice distortion induces large relative atomic displacement, so only a small indentation strain is required to meet the critical displacement threshold that triggers incipient plasticity. Therefore, for perfect crystals, lattice distortion is an intrinsic and determinative factor that affects the first pop-in event.
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Irreversible curing distortion represents a significant limiting factor in the application of high-performance composite structures. Curing distortion is the deviation of a component's profile from the theoretical profile after demolding. Introducing the optimal compensation profile into the traditional compensation algorithm represents an effective method to enhance CFRPs' forming accuracy. For this method, it is necessary to obtain the optimal compensating profile by establishing the coordinate model of the curing process parameter and mold profile compensation. The coordinated control model consists of four parameters: the mean value (Dav), root mean square value (Dmsr), minimum (Dmin), and maximum (Dmax) of curing distortion. Two sizes of composite structural parts are manufactured using the global compensation method. We investigate the influence mechanisms of heating, holding, and cooling times on curing distortion and residual stresses and develop a multi-field coupled finite element model. Strong agreement between the numerical and experimental findings serves as evidence for the effectiveness of the numerical model. The middle layer of the fabricated parts exhibit a reduction in residual stresses as the heating and holding times increase, while an opposite trend is noted with an increase in cooling time. Refining the design of curing process parameters can yield the minimum value of curing deformation within the specified resin system interval. Comparisons indicate that the distortion of the composite wall panel structure is reduced by 86.2% through the use of the global compensation method, demonstrating the validity of this approach for composite structures.
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Introduction Speech has a great impact on human evolution, allowing for the widespread knowledge and advancement of tools. Difficulty in pronouncing one or more sounds is the most common speech impairment. Speech defects are more commonly associated with class III malocclusion patients (difficulty in pronouncing 's' and 't' sounds), the second in line is class II malocclusion (difficulty in pronouncing 's' and 'z' sounds), and speech distortions are least affected in class I malocclusion (difficulty in pronouncing 's' and 'Sh'). Most patients with dentofacial disharmonies and speech distortions need orthodontic care and orthognathic surgery to resolve their issues with mastication, aesthetics, and speech. Aims and objectives To compare and assess speech difficulties in different types of malocclusion. Materials and methods The study was conducted over 160 subjects for three and half months. All of them were evaluated for speech defects before they received orthodontic treatment. The main basis of this study is according to Angle's classification of malocclusion. The subjects were segregated according to Angle's classification of malocclusion. Malocclusion traits that are included in this study are Angle's class I, Angle's class II division I and division II, and Angle's class III. Results According to the results, out of 160 subjects, labio-dental speech defects are observed in 8% where n=13 of the study participants, linguodental speech defects are observed in 2% where n=3, lingua-alveolar speech defects are present in 54% where n=86, and bilabial speech defects are observed in 2% where n=3 of the study participants. Here 'n' represents the frequency of the subjects. Severe speech defects are seen in Angle's class III malocclusion. Results according to the type of malocclusion include: labio-dental speech defects are seen in 37.5% in class I, 25% in class II division I, 0% in class II division II, and 37.5% in class III. Linguodental speech defects are seen in class III malocclusion subjects only. Lingua-alveolar sounds are seen in 27.8% of class I, 29.6% of class II division I, 1.9% of class II division II, and 40.7% of class III. Bilabial speech defects are only seen in class II division I subjects. According to the results, only lingua-alveolar speech defects are statistically significant, and more severe speech defects were observed in class III malocclusion. Conclusion Speech plays an important role in affecting the quality of life of people. Different types of malocclusion traits are associated with different types of speech defects.
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The phenomenon of high-frequency distortion (HFD) in the electric grids, at both low-voltage (LV) and medium-voltage (MV) levels, is gaining increasing interest within the scientific and technical community due to its growing occurrence and the associated impact. These disturbances are mainly injected into the grid by new installed devices, essential for achieving decentralized generation based on renewable sources. In fact, these generation systems are connected to the grid through power converters, whose switching frequencies are significantly increasing, leading to a corresponding rise in the frequency of the injected disturbances. HFD represents a quite recent issue, but numerous scientific papers have been published in recent years on this topic. Furthermore, various international standards have also covered it, to provide guidance on instrumentation and related algorithms and indices for the measurement of these phenomena. When measuring HFD in MV grids, it is necessary to use instrument transformers (ITs) to scale voltages and currents to levels fitting with the input stages of power quality (PQ) instruments. In this respect, the recently released Edition 2 of the IEC 61869-1 standard extends the concept of the IT accuracy class up to 500 kHz; however, the IEC 61869 standard family provides guidelines on how to test ITs only at power frequency. This paper provides an extensive review of literature, standards, and the main outputs of European research projects focusing on HFD and ITs. This preliminary study of the state-of-the-art represents an essential starting point for defining significant waveforms to test ITs and, more generally, to achieve a comprehensive understanding of HFD. In this framework, this paper provides a summary of the most common ranges of amplitude and frequency variations of actual HFD found in real grids, the currently adopted measurement methods, and the normative open challenges to be addressed.
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Inducing strain in the lattice effectively enhances the intrinsic activity of electrocatalysts by shifting the metal's d-band center and tuning the binding energy of reaction intermediates. NiFe-layered double hydroxides (NiFe LDHs) are promising electrocatalysts for the oxygen evolution reaction (OER) due to their cost-effectiveness and high catalytic activity. The distorted ß-NiOOH phase produced by the Jahn-Teller effect under the oxidation polarization is known to exhibit superior catalytic activity, but it eventually transforms to the undistorted γ-NiOOH phase during the OER process. Such a reversible lattice distortion limits the OER activity. In this study, we propose a facile boron tungstate (BWO) anion intercalation method to induce irreversible lattice distortion in NiFe LDHs, leading to significantly enhanced OER activity. Strong interactions with BWO anions induce significant stress on the LDH's metal-hydroxide slab, leading to an expansion of metal-oxygen bonds and subsequent lattice distortion. In situ Raman spectroscopy revealed that lattice-distorted NiFe LDHs (D-NiFe LDHs) stabilize the ß-NiOOH phase under the OER conditions. Consequently, D-NiFe LDHs exhibited low OER overpotentials (209 and 276 mV for 10 and 500 mA cm-2, respectively), along with a modest Tafel slope (33.4 mV dec-1). Moreover, D-NiFe LDHs demonstrated excellent stability at 500 mA cm-2 for 50 h, indicating that the lattice distortion of the LDHs is irreversible. The intercalation-induced lattice strain reported in this study can provide a general strategy to enhance the activity of electrocatalysts.
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In order to predict the maximum cavitation damage to hydraulic machinery in cryogenic engineering such as turbopumps in liquid rockets, it is essential to know the achievable intensity of bubble collapse. Rayleigh-Taylor instability imposes an extinction threshold for collapsing bubbles and determines the upper limit for the strongest collapse possible. In this study, we numerically investigate this information for collapsing bubbles in liquid oxygen. Our results reveal two distinct features of bubble instability in cryogenic liquids compared with that in water. First, high-order surface distortions are preferably developed on the bubble surface. Second, the bubble is most unstable when it collapses moderately, whereas it is stabilized as the collapse intensity is strengthened. A mechanistic study links these intriguing phenomena to the relatively slow bubble dynamics in cryogenic liquids. In that context, the growth time of the distortions emerges as a pivotal factor for the instability development. Together with the amplification rate, it controls the ultimate mode and amplitude of the instability.
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The distribution of China's energy resources is concentrated in the central and western regions, whereas the energy demand is predominantly centered in the eastern regions. Under the ambitious "carbon neutrality" goal, how to effectively quantify and respond to the impact of this energy "endowment-demand" distortion (EEDD) on economy and environment has become a key issue. We introduce an EEDD index that quantifies the distortion characteristics of China's energy endowment and demand. Based on the EEDD index, a panel vector auto regression-generalized method of moments (PVAR-GMM) model is adopted to assess the interactive effects between regional EEDD and sustainable development variables. The obtained results indicate that the energy endowment-demand distortions are progressively worsening across most provinces. Interestingly, we discover that the EEDD has significant beneficial effects on regional sustainable development. Moreover, the EEDD is found to be significantly influenced by the sustainability-related variables. These impacts between EEDD and sustainable development variables demonstrate significant regional heterogeneity. This study provides crucial empirical evidence for advancing the comprehensive and sustainable development of regional energy, environment, and economy.