Scanning Range Research Articles

Simulation of the shielding effect of lead apron undergoing chest CT scan.

Lead aprons are used to reduce radiation dose to patients. As the distance between the lead apron and the edge of the scan range increases, organ dose is expected to decrease, but with increasing scattered radiation dose in the body. By simulation, this work aims at estimate whether the organ dose increases due to the scattered radiation in the body with lead apron. A standard-sized male and a female phantom is used to simulate organ doses of chest scans in various lead apron shielding situations. Simulations in this work considered different distance between the edge of the 0.35-mm lead apron and the edge of the scan range. For the female phantom, the dose to the gonads was significantly reduced (56% on average), but not as much as men (78% on average). However, the amount of dose reduction is small for male and female phantoms (0.0082mGy/100mAs and 0.0160mGy/100mAs).

Rydberg electromagnetically induced transparency based laser lock to Zeeman sublevels with 0.6GHz scanning range.

We propose a technique for frequency locking a laser to the Zeeman sublevel transitions between the 5P3/2 intermediate and 32D5/2 Rydberg states in 87Rb. This method allows for continuous frequency tuning over 0.6GHz by varying an applied external magnetic field. In the presence of the applied field, the electromagnetically induced transparency (EIT) spectrum of an atomic vapor splits via the Zeeman effect according to the strength of the magnetic field and the polarization of the pump and probe lasers. We show that the 480nm pump laser, responsible for transitions between the Zeeman sublevels of the intermediate state and the Rydberg state, can be locked to the Zeeman-split EIT peaks. The short-term frequency stability of the laser lock is 0.15MHz, and the long-term stability is within 0.5MHz. The linewidth of the laser lock is ∼0.8 and ∼1.8MHz in the presence and absence of the external magnetic field, respectively. In addition, we show that in the absence of an applied magnetic field and adequate shielding, the frequency shift of the lock point has a peak-to-peak variation of 1.6MHz depending on the polarization of the pump field, while when locked to Zeeman sublevels, this variation is reduced to 0.6MHz. The proposed technique is useful for research involving Rydberg atoms, where large continuous tuning of the laser frequency with stable locking is required.

Shared Aperture Wideband Endfire/Broadside mm-Wave Phased Array With Enhanced Scanning Range Integrated With Metal Frame for Mobile Terminals

Shared Aperture Wideband Endfire/Broadside mm-Wave Phased Array With Enhanced Scanning Range Integrated With Metal Frame for Mobile Terminals

Design and implementation of a sample environment for in situ moisture-dependent neutron dark-field imaging experiments

We present the design and construction of a custom neutron-transparent sample environment for in situ moisture-dependent neutron dark-field imaging (NDFI) experiments for the imaging facilities at the Paul Scherrer Institute (PSI), Villigen, Switzerland. This simple setup, combined with a moisture generator, features a continuous flow system to ensure a constant homogeneous flow of humid air to manipulate the sample’s moisture conditions at room temperature. To facilitate neutron dark-field imaging measurements, the chamber has a slim design to maximize the sample-detector distance scanning range. The chamber can maintain static or dynamic relative humidity conditions, allowing for humidity cycles. Beyond moisture-dependent studies, the system’s versatility allows its utilization in any type of gas stream-dependent study. This technical note details the engineering considerations, construction process, and validation of this sample environment.

Inverse-Designed Ultra-Compact Passive Phase Shifters for High-Performance Beam Steering.

Ultra-compact passive phase shifters are inversely designed by the multi-objective particle swarm optimization algorithm. The wavelength-dependent phase difference between two output beams originates from the different distances of the input light passing through the 4 μm × 3.2 μm rectangular waveguide with random-distributed air-hole arrays. As the wavelength changes from 1535 to 1565 nm, a phase difference tuning range of 6.26 rad and 6.95 rad is obtained for TE and TM modes, respectively. Compared with the array waveguide grating counterpart, the phase shifters exhibit higher transmission with a much smaller footprint. By combining the inverse-designed phase shifter and random-grating emitter together, integrated beam-steering structures are built, which show a large scanning range of ±25.47° and ±27.85° in the lateral direction for TE and TM mode, respectively. This work may pave the way for the development of ultra-compact high-performance optical phased array LiDARs.

Size-specific dose estimates calculated using patient size measurements from scanned projection radiograph in high-resolution chest computed tomography.

Size-specific dose estimates (SSDE) are used to assess patient-specific radiation exposure in Computed Tomography (CT), complementing the volume CT dose index (CTDIvol). This study compared SSDE calculated using patient's lateral size from scan projection radiograph (SPR) with SSDE calculated using water equivalent diameter (Dw) from tomographic images in adult chest high-resolution CT (HRCT). In a single-centre study, the CTDIvol and dose-length product (DLP) were recorded from HRCT dose reports of adult patients. Lateral width (SLat), at the centre of the scan range, from the SPR was measured and the SSDE (SSDER) was calculated using conversion factors related to SLat. Average CT number, area of the slice, and lateral size of the patient (AxLat) were measured on the middle slice. The Dw and SSDE from Dw (SSDEW) were calculated. SSDER and SSDEW were compared using Wilcoxon signed rank test. Correlation between patient size and dosimetry parameters were investigated using Spearman Correlation test with statistical significance at P < 0.05. Bland-Altman plot was also used to test agreement between the two SSDE values. Median CTDIvol, DLP, SSDER and SSDEW were 11.0 mGy, 372 mGy.cm, 11.6 mGy and 12.9 mGy, respectively. Small but statistically significant differences (P < 0.03) were found between SLat and AxLat as well as between SSDER and SSDEW. Bland-Altman analysis resulted in borderline agreement between SSDE values. Moderate correlations were observed between dosimetry quantities and patient size measurements (ρ > 0.640; P < 0.001). SSDEw showed statistically significant correlation (ρ = 0.587 and P < 0.001) with SSDER. SSDER may be used to assess patients' absorbed radiation dose, before the scan, in adult chest HRCT. The median value of SSDER was about 10% lower than the median value SSDEW. However, the SSDEW should be used after the scan to establish effective dose and radiation risk to the patient.

A novel millimetre‐wave 2D wide‐angle scanning phased array antenna based on decoupling surface

AbstractThis paper presents a novel millimetre‐wave (mmWave) 2D wide‐angle scanning (WAS) phased array antenna (PAA) based on decoupling surface (DS). The proposed element is a coaxial feeding stacked patch antenna structure that consists of an L‐shape coaxial probe, substrate integrated waveguide cavity, slot layer, radiating patch, DS and defective ground structure. The simulated impedance bandwidth for the element is 14.85% (26.18–30.34 GHz). The simulated result of the 2 × 2 array shows that the designed antenna based on DS achieves an isolation of ≥19 dB within the bandwidth. To validate the scanning capabilities of the proposed antenna, an 8 × 8 PAA prototype is fabricated and measured. The measured scanning range of the prototype achieves a 2D WAS range of ±56° at 27 GHz. The proposed antenna shows great potential in application scenarios, such as automotive radar and satellite communication due to its compact design and ability to achieve WAS in two dimensions.

The out-of-plane contact shield and mA-modulation- the effect on fetal absorbed dose.

The effect of patient shielding on fetal radiation dose was evaluated in computed tomography pulmonary angiography with the out-of-plane shield visible in the localizer but absent in the scan range in chest computed tomography (CT). An anthropomorphic phantom with additional prosthetic pregnancy belly was scanned with different CT scanners using clinical imaging protocols and radiophotoluminescence dosemeters (GD-352M). The out-of-plane shield decreased the fetal absorbed radiation dose with Siemens Somatom go.Up, Canon Aquilion Prime SP and Canon Aquilion One scanners. The decrease was 3.9%-39.4% (0.01-0.09mGy). With GE Optima the shield increased the fetal dose by 100% (0.23mGy), with Canon Aquilion One and GE Optima scanners the abdomen dose increase was 17.5% and 36.4%, respectively (0.61 and 1.38mGy). Applying an out-of-plane shield outside the scanned volume may increase the fetal radiation dose during CT when using tube current modulation, depending on the make and model of the CT scanner.

Impressive electrochemical characteristics of freeze-dried nanosheet structured Mn2P2O7 for affordable electrochemical capacitor

The electrochemical capacitive performance of supercapacitors (SCs) is mainly evaluated by active electrode material, which plays a critical participation. At present, transitional metallic pyrophosphates (TMPs) have grabbed more interest as active electrodes in SC configuration. In this work scenario, we informed a novel strategic synthesis route for constructing Mn2P2O7 (MP) through an ultrasonic probe-assisted chemical reaction approach. The electrode in the form of a monoclinic, freeze-dried nanosheet structure characterized by XRD, FESEM- TEM, and its signature chemical bonds and chemical composition were confirmed via FTIR and EDS analysis, respectively. As prepared active sample was successfully sent into electrochemical investigation tools such as Cyclic Voltagrams (CV), Galvanostatic charge/discharge (GCD), electrochemical impedance analysis (EIS), and Cycling life span (stability) using three and two-electrode set-up. These tests indicate that the active sample holds an impressive capacitive value of 558 F/g at scanning range of 2 mV/s, a specific capacity of 420 C/g at 1 A g-1, magnificent rate capability, 90 % retention over 10,000 successive voltammograms in three-electrode measurements. Additionally, the fabricated symmetric supercapacitor device shows superior energy density, power density, and good rate capability in two electrode investigations. The mentioned prominent results reflect that engineered MP and its characteristics are the efficient fruits in manufacturing affordable electrochemical capacitors.

Microstructural response of coal fracture surface induced by ScCO2 injection measured with AFM

Fractures in coal serve as the principal channels for the migration of coalbed methane (CBM). The microscopic traits of coal fracture surface are of significance for evaluating reservoir permeability and directly influence the outcome of CO2 storage and displacement. To comprehend the impact of CO2 on the coal fracture surface, the alterations in the coal fracture surface before and after CO2 injection are investigated vis atomic force microscopy. As CO2 gradually transforms into a supercritical state, the fracture density and aperture on the coal fracture surface gradually escalate. The mean pore size and porosity of the coal fracture surfaces rose from 5.45 nm to 6.55 nm and from 4.66% to 6.85%, respectively. The proportion of micropores (<2 nm) gradually diminished. The proportions of mesopores (2∼50 nm) and macropores (>50 nm) proportions gradually. Swelling, extraction and mineral dissolution are the predominant reasons for the alteration in the pore structure of the coal fracture surface. CO2 injection modifies the roughness and fractal characteristics of the coal fracture surface. The mean roughness Ra dropped from 6.54 nm to 4.03 nm, and the fractal dimension Ds declined from 2.45 to 2.28. With the fixed scanning range, the injection of CO2 has been shown to reduce the roughness of coal fracture surface and lower their fractal dimension, thereby has a positive influencing permeability enhancement. Therefore, in CO2-ECBM engineering, it is essential not only to analyse the physical properties of the target reservoir, but also to conduct a comprehensive evaluation of permeability with a suitably defined area of the reservoir.

Diagnosis of newly developed multiple myeloma without bone disease detectable on conventional computed tomography (CT) scan by using dual-energy CT

ObjectiveTo evaluate the diagnostic utility of fat (hydroxyapatite) density [DFat (HAP)] on dual-energy computed tomography (DECT) for identifying clinical diagnosed multiple myeloma without bone disease (MNBD) that is not visible on conventional CT scans. Material and MethodsIn this age-gender-examination sites matched case control prospective study, Chest and/or abdominal images on Revolution CT of MNBDs and control subjects were consecutive enrolled in a 1:2 ratio from October 2022 to November 2023. Multiple myeloma was clinical diagnosed according to criteria of the International Myeloma Working Group. Regions of interest (ROIs) were drawn separately for all thoracolumbar vertebrae in the scanning range by two radiologists. Additionally, a radiologist specializing in musculoskeletal imaging supervised the process. DFat (HAP) was extracted from each ROI. The spine was divided into upper thoracic (UPT), middle and lower thoracic (MLT), thoracolumbar (TL), and middle and lower lumbar (MLL) vertebrae. The area under the receiver operating characteristic curve (AUC) was calculated to evaluate the diagnostic performance of DFat (HAP) in diagnosing multiple myeloma, and the sensitivity, specificity, and accuracy under the optimal cut-off were determined by Youden index (sensitivity + specificity −1). ResultsA total of 32 and MNBD patients and 64 control patients were included. The total number of ROIs outlined included MNBD group (n = 493) and control group (n = 986). For all vertebrae, DFat(HAP) got average performance in the diagnosis of MNBD (AUC = 0.733, p < 0.001) with a cut-off value of 958 (mg/cm3); the sensitivity, specificity, and accuracy were 58.8 %, 77.8 %, and 71.7 %, respectively. Regarding segment analysis, the diagnostic performance was good for all (AUC, 0.803–0.837; p < 0.001) but the UPT segment (AUC = 0.692, p = 0.002). The optimal diagnostic cut-off values for the MLT, TL, and MLL vertebrae were 955 mg/cm3, 947 mg/cm3, and 947 mg/cm3, respectively; the sensitivity, specificity, and accuracy were 80.0 %-87.5 %, 71.9 %-82.6 %, and 77.1 %-81.6 %, respectively. ConclusionDECT was effective for detecting MNBD, and better diagnostic results can be obtained by grouping different spine segments.

A Design Proposal Using Coherently Radiating Periodic Structures (CORPSs) for 2-D Phased Arrays of Limited Scanning

New configurations of 2-D phased arrays are proposed in this paper for reducing the number of phase shifters. This design methodology is based on the use of a novel coherently radiating periodic structures (CORPSs) block for 2-D phased arrays. Two new antenna systems for 2-D phased arrays are studied and analyzed utilizing the CORPSs blocks of four inputs and nine outputs. These CORPSs feeding blocks are applied in a smart way to feed the planar antenna arrays by generating the required phase plane and reducing the number of control ports. Interesting results are provided based on the experimental measurements and full-wave simulations. These results illustrate a great reduction of the active devices (phase shifters), providing a good design compromise in terms of the scanning range and side lobe level performance. Furthermore, the provided results illustrate a maximum reduction capability in the number of phase shifters of 81%, considering a scanning range of ±30° in azimuth and ±30° in elevation. A raised cosine distribution is applied to reach side lobe levels of −19 dB for ±18° and −17 dB for ±30° in elevation. These benefits could be of interest to designers of phased antenna systems.

Redox-Active Polyaniline Covalently grafted Black Phosphorus Nanosheets for Integrated Digital-Analogue Memristors.

Surface covalent modification of black phosphorus (BP) with organic polymers represents a promising strategy to enhance its stability and tailor its electronic properties. Despite this potential, developing memristive materials through suitable polymer structures, grafting pathways, and polymerization techniques remains challenging. In this study, polyaniline (PANI)-covalently grafted black phosphorus nanosheets (BPNS) are successfully prepared with redox functionalities via the in situ polymerization of aniline on the surface of 4-aminobenzene-modified BPNS. The PANI coating protects the BP from direct exposure to oxygen and water, and it endows the material with analog memristive properties, characterized by a continuously adjustable resistance within a limited voltage scan range. When subjected to a broader voltage scan, the Al/PANI-g-BPNS/ITO device demonstrates a typical bistable digital memristive behavior. The integration of both digital and analog memristive functionalities in a single device paves the way for the development of high-density, multifunctional electronic components.

Full‐angle beam scanning leaky‐wave antenna array based on spoof surface plasmon polaritons

AbstractA design scheme of high‐gain and full‐angle frequency beam scanning leaky wave antenna (LWA) and array is proposed based on spoof surface plasmon polaritons (SSPPs) slow‐wave transmission line (TL) for radar field applications. A row of complementary split ring resonators is periodically etched near the SSPPs TL, which can transform the fundamental mode of SSPPs TL to the fast‐wave region and radiate electromagnetic waves, realising the full‐angle frequency beam scanning performance. A 1‐to‐2 microwave power divider is designed to feed the LWA array and realised good impedance matching covers 5.8–9.4 GHz bandwidth. Simulation and experimental results indicate that the designed LWA array can realise full‐angle beam scanning range of 180° (−90° to 90°) with a scanning rate of 3.83°/% performance. The peak gain values of the designed LWA element and array are 11.4dBi and 14.6 dBi, respectively, and the radiation efficiency of LWA array is maintained more than 80% within the operation frequency band.

A wide angle beam scanning CRLH leaky-wave antenna with non-identical elements per unit-cells

In this research article, a wide-angle scanning leaky-wave antenna (LWA) based on the composite right/left-handed (CRLH) metamaterial (MTM) operating over the C-band spectrum for mobile applications is proposed, investigated, and realized. The proposed LWA includes nine CRLH-MTM-based unit-cells. The properties of CRLH-MTM have been applied using series slots and shunt metallic via-holes. Each unit cell consists of three patches, two external patches, and one smaller middle patch implemented between them. One slot has been etched on each external patch; the width of these two slots is unequal. Moreover, the distance of the middle patch with each side patch is different. The results show that using this method of realizing non-identical elements caused the achievement of proper return-loss at the transition frequency and provided the balanced CRLH metamaterial condition. Additionally, using CRLH-MTM properties by realizing series capacitance (slot) and shunt inductance (via-holes) made the wide-angle scant from backward to forward radiation pattern. The results demonstrate that the LW antenna with small dimensions of 251.5 × 30 × 1.575 mm3 operates over a frequency range of 4.8–6.13 GHz covering a wide beam scanning range from −63° to +65° with broadside radiation at the center frequency of 5.46 GHz. The radiation gain of the proposed antenna varies from 6.2–13.1 dB. The achievements confirm the effectiveness of the proposed methods to realize a high-performance LW-antenna with the advantages of simple design, low profile, low cost, and easy of manufacture for mobile applications.

Investigation of the beam quality and dose rate dependence of PAKAG polymer gel dosimeter in optical readout technique

This study aims to evaluate the optical response dependence of the PAKAG polymer gel dosimeter on photon energy and dose rate. The produced gel dosimeters were irradiated using a Varian CL 21EX medical linear accelerator with delivered doses of 0, 2, 4, 6, 8, and 10 Gy. To examine the response dependence on the delivered dose rate, dose rates of 50, 100, 200, and 350 cGy min−1 were investigated. Additionally, two incident beam qualities of 6 and 18 MV were examined to study the response dependence on the incident beam energy. The irradiated polymer gel dosimeters were readout using a UV–vis spectrophotometer in the 300 to 800 nm scan range. The results reveal that a wide variation in dose rate (50–350 cGy.min−1) influences the absorbance-dose response and the sensitivity of PAKAG gel. However, smaller variations did not show a significant effect on the response. Furthermore, the response changed insignificantly with beam quality for investigated energies. It was concluded that the optical reading response of the PAKAG polymer gel dosimeter is satisfactorily independent of external parameters, including dose rate and incident beam quality.

Accuracy of bite registration according to the buccal bite scan range of intra-oral scanner

Accuracy of bite registration according to the buccal bite scan range of intra-oral scanner

Mapping high-resolution XCO2 concentrations in China from 2015 to 2020 based on spatiotemporal ensemble learning model

High-resolution column-averaged dry air mole fraction of CO2 (XCO2) data is crucial for understanding the spatiotemporal patterns of XCO2 and for mitigating carbon emissions. Due to the limited scanning range of sensors and strict inversion conditions, satellite-retrieved XCO2 data are often significantly incomplete. Machine learning models are widely used to fill these gaps in satellite XCO2 data. However, the limitations of individual machine learning models and the complexity of the spatial distribution of XCO₂ mean that the accuracy of XCO2 predictions still needs improvement. In this study, a new spatiotemporal stacked ensemble learning model (STEL) was developed by combining random forest (RF), extremely randomized trees (ERT), extreme gradient boosting (XGBoost), optical gradient boosting (LightGBM), and categorical boosting (CatBoost) using the stacking ensemble learning methodology. Considering the spatiotemporal heterogeneity of XCO2, a novel spatiotemporal weighting feature was constructed as part of the model's input parameters. Finally, the XCO2 observed by Orbiting Carbon Observatory 2 (OCO-2) was reconstructed using STEL, and a monthly mean XCO2 dataset covering China from 2015 to 2020 was generated at a spatial resolution of 0.1°. The results show that STEL exhibits superior performance and generalization capabilities compared to individual machine-learning models. R2 RMSE and MAPE were 0.9624, 1.0023 ppm, and 0.1583 % on the test set, and 0.8970, 1.4213 ppm, and 0.2475 % for R2, RMSE, and MAPE in ground validation, respectively. In 10-fold cross-validation, STEL's RMSE was reduced by 9.52 % compared to the best-performing single model (RF). The spatiotemporal trend of CO2 in China from 2015 to 2020 was analyzed using STEL XCO2 data. The results indicate that this dataset accurately reflects the spatiotemporal heterogeneity of XCO2 distribution at a fine scale. Overall, XCO2 exhibited a spatiotemporal pattern of “high in the east and low in the west” and “high in spring and low in summer.” Except in summer, high XCO₂ values were mainly distributed in the North China Plain. XCO2 trends and hotspots showed considerable spatial variation. The Pearl River Delta and Yangtze River Delta urban agglomerations have the fastest XCO2 growth rates, and the distribution of XCO2 hotspots is consistent with the distribution of population and economic centers. In the sparsely populated northwest of China, XCO2 is growing rapidly due to increased thermal power generation and coal mining. XCO2 hotspots in Northwest China are mainly located in Xinjiang, Ningxia, and Inner Mongolia. The methodology and data presented are useful for further research on carbon emissions, carbon sinks, and climate change.

Optical design and analysis of a high-speed triple galvanometer laser 3D scanning system

In this paper, a triple galvanometer laser three-dimensions (3D) scanning system (TGLSS) was proposed. The system consisted of three galvanometers and two parabolic mirrors, with rapid movement of the laser focus in 3D space by rotations of the three galvanometers. The optical principle of the TGLSS was analyzed, and the method of designing TGLSS by geometrical optics and Abbe’s sine condition was given in detail. Scanning range and focusing quality were analyzed by optical simulations. An experiment was carried out to verify the feasibility of TGLSS. The implications of TGLSS for reflective dynamic focusing device (RDFD)-based laser system and their impact on technologically relevant applications were discussed. The great potential for enhancing the speed of advanced laser processing in 3D space was offered by TGLSS.

Degradation and Migration in Olive Oil Packaged in Polyethylene Terephthalate under Thermal Treatment and Storage Conditions

The research addresses challenges in food safety related to the migration of contaminants from plastics to food. It focused on the physicochemical and sensory degradation of olive oils packaged in polyethylene terephthalate (PET) and subjected to thermal exposure at 40 °C and 60 °C for several weeks and a subsequent 12 months of storage, as well as the stability and migration of compounds from the PET packaging itself. Olive oils (OO) from Spanish supermarkets (a mixture of refined and virgin, with commercial identifications of mild and intense) were selected and subjected to thermal treatments at 40 °C and 60 °C for 1, 2, and 3 weeks, followed by 12 months of storage. The treatments were conducted through the following two independent experiments: Experiment A focused on immediate analysis post-thermal treatment, while Experiment B included a 12-month storage period post-thermal treatment. The presence of antimony (Sb) was analyzed using acid digestion with nitric acid (HNO3) and high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS), while the metals cadmium (Cd), copper (Cu), lead (Pb), and iron (Fe) were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The PET characterization was assessed using Fourier transform infrared spectroscopy in the mid-infrared range (FT-IR/MIR), carbonyl index, and differential scanning calorimetry (DSC). The results showed increases in the acidity index by 0.29%, the peroxide value by 25.92%, and the K268 coefficient by 51.22% between the control sample and the most severe treatments, with more pronounced effects observed after 12 months. Sensory quality declined, with reduced intensity of the “fruity” attribute and increased presence of the “rancid” defect. PET degradation was reflected in an increase in the carbonyl index and greater structural amorphization. Fe was the predominant metal, and Sb concentration increased after thermal treatments. The lack of studies on the raw consumption of oils packaged in PET and the concerns about the migration of compounds from the packaging to the food highlight the relevance of this research. This study provides new insights into the effects of thermal exposure and storage on the migration of PET contaminants into oils, contributing to the development of strategies to ensure food safety and product quality.