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Background Few reliable methods to simulate and evaluate the intersegmental plane have been reported. We introduce intersegmental plane simulation based on the bronchus-vein-artery triad in three-dimensionally reconstructed images from patients who underwent segmentectomy for early lung cancer. Methods We collected clinical data of consecutive patients with early-stage lung cancer who underwent three-dimensional imaging-guided single-port thoracoscopic segmentectomy at Department No. 1 of Thoracic Surgery at Fujian Medical University Fujian Union Hospital from January 2019 to July 2019. Patients were divided into two groups according to the application of intersegmental plane simulation and nodule analysis: the intersegmental plane group and the non-intersegmental plane group. General clinical characteristics, operation status, and postoperative recovery were compared between groups. The three-dimensional reconstruction results in the intersegmental plane group were analyzed and summarized. Results A total of 120 patients were included (61 in the intersegmental plane group and 59 in the non-intersegmental plane group). There were no significant differences between the two groups in general characteristics (all P>0.05). All target lesions were resected in both groups. There were no significant differences between groups in operation characteristics or postoperative recovery, with the exception of the duration of chest drainage and the rate of gross margin insufficiency. There were five cases of gross margin insufficiency in the non-intersegmental plane group. With three-dimensional imaging reconstruction, a total of 131 intersegmental veins could be used to evaluate the simulated intersegmental plane in 61 patients, with an average of 2.1±0.5 veins per patient. Two patients (3.3%) had one vein that could be used to evaluate the intersegmental plane, 50 patients (82.3%) had two, seven patients (11.3%) had three, and two patients (3.3%) had four. The total number of intersegmental veins located on the simulated intersegmental plane was 124 (94.7%), with an average of 2.0±0.6 veins per patient. The accuracy of intersegmental plane simulation was 91.8% (56/61). Conclusions The bronchus-vein-artery triad in intersegmental plane simulation can assist surgeons in preoperative planning and can facilitate complete resection of early lung cancer with sufficient surgical margins.

Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) enable the visualization of three-dimensional (3D) microstructures ranging from atomic to micrometer scales using 3D reconstruction techniques based on computed tomography algorithms. This 3D microscopy method is called electron tomography (ET) and has been utilized in the fields of materials science and engineering for more than two decades. Although atomic resolution is one of the current topics in ET research, the development and deployment of intermediate-resolution (non-atomic-resolution) ET imaging methods have garnered considerable attention from researchers. This research trend is probably not irrelevant due to the fact that the spatial resolution and functionality of 3D imaging methods of scanning electron microscopy (SEM) and X-ray microscopy have come to overlap with those of ET. In other words, there may be multiple ways to carry out 3D visualization using different microscopy methods for nanometer-scale objects in materials. From the above standpoint, this review paper aims to (i) describe the current status and issues of intermediate-resolution ET with regard to enhancing the effectiveness of TEM/STEM imaging and (ii) discuss promising applications of state-of-the-art intermediate-resolution ET for materials research with a particular focus on diffraction contrast ET for crystalline microstructures (superlattice domains and dislocations) including a demonstration of in situ dislocation tomography.

Rimozione trans-orale dei calcoli sottomandibolari ilo-parenchimali profondi con tecnica videoassistita 3D.L’articolo descrive la prima applicazione dell’endoscopia 3D in alta definizione (3D-HD) nella rimozione chirurgica transorale di calcoli sottomandibolari siti in sede ilo-parenchimale profonda in cinque pazienti. Vengono riportati i riscontri intraoperatori ed i risultati chirurgici ottenuti in questo gruppo di pazienti; cinque pazienti sottoposti a chirurgia transorale videoassistita con endoscopi 2D-HD per la medesima patologia sono stati utilizzati come controlli. Il follow-up clinico ed ecografico è stato effettuato ad un mese di distanza dal trattamento chirurgico. Il successo della procedura è stato definito dalla completa clearance del calcolo alla valutazione ecografica. La valutazione della nitidezza, luminosità e della percezione stereoscopica della profondità (SDP) delle immagini 3D e 2D è stata definita mediante valutazione soggettiva dei chirurghi eseguita post-operativamente mediante una scala di valutazione analogica (VAS). La rimozione chirurgica completa dei calcoli ed un miglioramento soggettivo (attestato dalla risoluzione sintomatologica) sono stati ottenuti in tutti i pazienti, eccetto in un paziente appartenente al gruppo 3D in cui è stata riscontrata ecograficamente la presenza a livello ilo-parenchimale di un piccolo calcolo residuo asintomatico di 3 mm, successivamente trattato con litotrissia intracorporea laser con completa clearance. Il dotto di Wharton ed il nervo linguale sono stati correttamente identificati e preservati in tutti i casi. Le VAS medie relative alla luminosità, nitidezza e SDP delle immagini 3D-HD sono risultate rispettivamente 7 (range 6-8), 7,8 (range 7-9), e 8,2 (range 8-9); le VAS medie relative alla luminosità e nitidezza delle immagini 2D-HD sono risultate rispettivamente 7,8 (range 7-9), 7 (range 7-8). In conclusione i nostri riscontri confermano la sicurezza ed efficacia dell’approccio chirurgico conservativo transorale per la rimozione di calcoli ilo-parenchimali. Sulla base dei riscontri intraoperatori e del livello di confort riferito post-operativamente dai chirurghi, l’esplorazione endoscopica 3D-HD sembra fornire una migliore visualizzazione delle strutture anatomiche nobili limitrofe, specialmente nelle vicinanza del parenchima sottomandibolare. Il supporto dell’endoscopia 3D-HD sembra pertanto utile a migliorare la performance chirurgica e a preservare i meccanismi funzionali nella riabilitazione chirurgica dei disordini ostruttivi salivari.The aim of this paper is to describe the intra-operative findings and surgical results of the first application of 3D high-definition (HD) endoscopic support to the trans-oral surgical treatment of five patients with deep hilo-parenchymal sub-mandibular stones who underwent clinical and ultrasonographic (US) follow-up examinations at one month after the procedure. Five patients undergoing 2D-HD video-assisted transoral surgery for the same condition were used as controls. The results were classified as successful (US - demonstrated complete clearance) or unsuccessful (US - demonstrated total or partial persistence). Visual analogue scales (VAS) were used post-surgically to evaluate the sharpness and brightness of the 2D and 3D images on the screen and stereoscopic depth perception (SDP) of the 3D-HD endoscope. Successful stone removal and significant subjective improvement (lack of obstructive symptoms) was obtained in all but one of the patients in the 3D group, in whom the one-month US evaluation revealed a residual 3 mm asymptomatic hilo-parenchymal stone that was successfully treated by sialendoscopy-assisted intra-corporeal laser lithotripsy. Wharton’s duct and the lingual nerve were identified and preserved in all cases. The mean 3D-HD VAS results were brightness 7 (range 6-8), sharpness 7.8 (range 7-9) and SDP 8.2 (range 8-9); the mean 2D-HD results were brightness 7.8 (range 7-9) and sharpness 7 (range 7-8). Our findings confirm the safety and efficacy of conservative transoral surgical treatment of hilo-parenchymal sub-mandibular stones. From a surgeon’s perspective, 3D-HD guided exploration of the oral floor seems to provide a better view of Wharton’s duct and the lingual nerve, especially near the sub-mandibular parenchyma. The 3D-HD video-assisted transoral removal of deep hilo-parenchymal sub-mandibular stones can therefore be considered a useful new means of preserving the function of an obstructed salivary gland.

Background: This retrospective study quantifies target vessel displacement during fenestrated and branched endovascular aneurysm repair due to the introduction of stiff guidewires and stent graft delivery systems. The effect that intraoperative vessel displacement has on the usability of computed tomography angiography (CTA) roadmaps is also addressed. Methods: Patients that underwent fenestrated or branched EVAR were included in this retrospective study. Two imaging datasets were collected from each patient: (I) preoperative CTA and (II) intraoperative contrastenhanced cone beam computed tomography (ceCBCT) acquired after the insertion of the stiff guidewire and stent graft delivery system. After image registration, the 3D coordinates of the ostium of the celiac artery, superior mesenteric artery, right renal artery and left renal artery were recorded in both the CTA and the ceCBCT dataset by two observers. The three-dimensional displacement of the ostia of the target vessels was calculated by subtracting the coordinates of CTA and ceCBCT from one another. Additionally, the tortuosity index and the maximum angulation of the aorta were calculated. Results: In total 20 patients and 77 target vessels were included in this study. The ostium of the celiac, superior mesenteric, right renal and left renal artery underwent non-uniform three-dimensional displacement with mean absolute displacement of 8.2, 7.7, 8.2 and 6.2 mm, respectively. The average displacement of all different target vessels together was 7.8 mm. A moderate correlation between vessel displacement and the maximum angulation of the aortoiliac segment was found (Spearman's ρ=0.45, P

The recent growth of learning technologies has catalyzed the surge in investments in e-learning systems across higher education to revolutionize pedagogical practices. Thus, the implementation of 3D virtual learning tools has become an indispensable, standard methodological tool in higher education. More recently, the enforcement of restrictions and emergency lockdowns to curb the spread of the COVID-19 pandemic compelled higher education institutions worldwide to cope with and meet the requirements of online education while preserving the quality of the learning experience at an equal pace. To develop a 3D physics laboratory, the appropriate equipment for physical experiments was first collected, then, the design software was applied to construct the 3D model. Software was then developed to edit the 3D experimental environment. Two practical tests were performed on the completed setup to verify the disadvantages and feasibility of the experiments. The present study develops and validates the incorporation of user satisfaction approaches to examine the quality of the most influential 3D learning tools during the coronavirus outbreak. The findings of this study confirm that 3D laboratories can positively influence learning attitudes when it comes to physics and improve learners’ understanding of physics concepts, they also confirm that 3D laboratories are a suitable tool for teaching physics experiments. Finally, the difficulties and solutions encountered in the development of the 3D laboratory are outlined as a reference for subsequent studies.

Breakthroughs in stem cell technology have contributed to disease modeling and drug screening via organoid technology. Organoid are defined as three-dimensional cellular aggregations derived from adult tissues or stem cells. They recapitulate the intricate pattern and functionality of the original tissue. Insulin is secreted mainly by the pancreatic β cells. Large-scale production of insulin-secreting β cells is crucial for diabetes therapy. Here, we provide a brief overview of organoids and focus on recent advances in protocols for the generation of pancreatic islet organoids from pancreatic tissue or pluripotent stem cells for insulin secretion. The feasibility and limitations of organoid cultures derived from stem cells for insulin production will be described. As the pancreas and gut share the same embryological origin and produce insulin, we will also discuss the possible application of gut organoids for diabetes therapy. Better understanding of the challenges associated with the current protocols for organoid culture facilitates development of scalable organoid cultures for applications in biomedicine. [BMB Reports 2019; 52(5): 295-303].

Objectives The aim of this study was to measure the mediastinal-thoracic volume ratio (CTR_VOL) on PMCT as a more accurate version of traditional CTR, in order to assess the terminal positional relationship between the heart and lungs in the different causes of death with regard to age, gender, BMI, cardiomegaly, and lung expansion. Materials Two hundred fifty consecutive postmortem cases with pre-autopsy PMCT and full forensic autopsy were retrospectively evaluated. The lungs and the mediastinum were manually segmented on the PMCT data and the correspondent volumes were estimated in situ. CTR_VOL was calculated as the ratio of the mediastinal to the thoracic volume. The volume measurements were repeated by the same rater for the evaluation of the intrarater reliability. Age, gender, body weight and height, heart weight at autopsy, and cause of death were retrieved from the autopsy reports. Presence of lung expansion was radiologically evaluated in situ. Results CTR_VOL was positively associated with age and BMI but not with gender and was higher for cardiomegaly compared to normal hearts, lower for asphyxiation-related deaths compared to cardiac deaths and intoxications, and lower for cases with lung expansion. The intrarater reliability was excellent for the calculated volumes of both lungs and mediastinum. Conclusion The results of the present study support CTR_VOL as a tool to assess the relationship between the heart and lungs in situ, which differs significantly between the studied cause of death categories.

Background and Objective: In the first trimester of pregnancy, fetal growth, and abnormalities can be assessed using the exact middle sagittal plane (MSP) of the fetus. However, the ultrasound (US) image quality and operator experience affect the accuracy. We present an automatic system that enables precise fetal MSP detection from three-dimensional (3D) US and provides an evaluation of its performance using a generative adversarial network (GAN) framework. Method: The neural network is designed as a filter and generates masks to obtain the MSP, learning the features and MSP location in 3D space. Using the proposed image analysis system, a seed point was obtained from 218 first-trimester fetal 3D US volumes using deep learning and the MSP was automatically extracted. Results: The experimental results reveal the feasibility and excellent performance of the proposed approach between the automatically and manually detected MSPs. There was no significant difference between the semi-automatic and automatic systems. Further, the inference time in the automatic system was up to two times faster than the semi-automatic approach. Conclusion: The proposed system offers precise fetal MSP measurements. Therefore, this automatic fetal MSP detection and measurement approach is anticipated to be useful clinically. The proposed system can also be applied to other relevant clinical fields in the future.

Graphene for energy storage devices suffers from the preparation method and deficient quality, hindering their further widespread application. Here, we report a facile and cost-effective approach to derive three-dimensional porous graphene (3DPG) from biocompatible chitosan for massive production. Taking advantage of the large surface area, excellent electrical conductivity and high electrochemical activity of the 3DPG, an advanced symmetric supercapacitor (3DPG//3DPG SCs) is achieved by coupling two 3DPG electrodes in commercial DLC301 organic electrolyte. The device delivers a remarkable capacitance of 168.9 F g-1 at the scan rate of 10 mV s-1 and displays a superior rate capability, witnessing 81.5% capacitance retention from 10 to 100 mV s-1. Furthermore, the 3DPG//3DPG SCs exhibits prominent cyclic durability, as evidenced by its 96% capacitance after 10,000 cycles. This work might shed light on the probable application of graphene at industrial level for efficient energy storage.

Millimeter-wave (mm-wave) spectrum unravels the humongous and accelerating demand for wireless data rates and, therefore, it will be a fundamental ingredient of the fifthgeneration (5G) wireless technology. In case of mm-wave access links, humans are the most noticeable blockers of electromagnetic waves from access points to mobile stations and hence cause temporal variation in the radio channel. This paper presents human blockage measurements in the anechoic chamber at 15, 28 and 60GHz frequencies employing 15 human subjects of different sizes and weights. An effective three-dimensional human blockage model as a double-truncated and absorbing multiple knife-edge (DTMKE) scheme is also proposed. By calculating diffraction from the DTMKE, the frequency, body orientation and antenna height dependency of the blockage are most accurately reproduced compared to the existing models, such as absorbing double knife-edge model and third generation partnership project (3GPP) human blockage model. The results demonstrate that the losses are proportional to the cross-section of the human body with respect to the radio link. Furthermore, the blockage loss decreases as the height of the transmitting antenna increases.

[EN] Multiple-input multiple-output (MIMO) radars have been shown to improve target detection for surveillance applications thanks to their proven high-performance properties. In this paper, the design, implementation, and results of a complete 3-D imaging frequency-modulated continuous-wave MIMO radar demonstrator are presented. The radar sensor working frequency range spans between 16 and 17 GHz, and the proposed solution is based on a 24-transmitter and 24-receiver MIMO radar architecture, implemented by timedivision multiplexing of the transmit signals. A modular approach based on conventional low-cost printed circuit boards is used for the transmit and receive systems. Using digital beamforming algorithms and radar processing techniques on the received signals, a high-resolution 3-D sensing of the range, azimuth, and elevation can be calculated. With the current antenna configuration, an angular resolution of 2.9° can be reached. Furthermore, by taking advantage of the 1-GHz bandwidth of the system, a range resolution of 0.5 m is achieved. The radio-frequency front-end, digital system and radar signal processing units are here presented. The medium-range surveillance potential and the high-resolution capabilities of the MIMO radar are proved with results in the form of radar images captured from the field measurements.

Purpose: To perform a clinical assessment of quantitative three-dimensional (3D) dynamic contrast-enhanced ultrasound (DCE-US) feasibility and repeatability in patients with liver metastasis, and to evaluate the extent of quantitative perfusion parameter sampling errors in 2D compared to 3D DCE-US imaging. Materials and Methods: Twenty consecutive 3D DCE-US scans of liver metastases were performed in 11 patients (45% women; mean age, 54.5 years; range, 48-60 years; 55% men; mean age, 57.6 years; range, 47-68 years). Pairs of repeated disruption-replenishment and bolus DCE-US images were acquired to determine repeatability of parameters. Disruption-replenishment was carried out by infusing 0.9 mL of microbubbles (Definity; Latheus Medical Imaging) diluted in 35.1 mL of saline over 8 min. Bolus consisted of intravenous injection of 0.2 mL microbubbles. Volumes-of-interest (VOI) and regions-or-interest (ROI) were segmented by two different readers in images to extract 3D and 2D perfusion parameters, respectively. Disruption-replenishment parameters were: relative blood volume (rBV), relative blood flow (rBF). Bolus parameters included: time-to-peak (TP), peak enhancement (PE), area-under-the-curve (AUC), and mean-transit-time (MTT). Results: Clinical feasibility and repeatability of 3D DCE-US using both the destruction-replenishment and bolus technique was demonstrated. The repeatability of 3D measurements between pairs of repeated acquisitions was assessed with the concordance correlation coefficient (CCC), and found to be excellent for all parameters (CCC > 0.80), except for the TP (0.74) and MTT (0.30) parameters. The CCC between readers was found to be excellent (CCC > 0.80) for all parameters except for TP (0.71) and MTT (0.52). There was a large Coefficient of Variation (COV) in intra-tumor measurements for 2D parameters (0.18-0.52). Same-tumor measurements made in 3D were significantly different (P = 0.001) than measurements made in 2D; a percent difference of up to 86% was observed between measurements made in 2D compared to 3D in the same tumor. Conclusions: 3D DCE-US imaging of liver metastases with a matrix array transducer is feasible and repeatable in the clinic. Results support 3D instead of 2D DCE US imaging to minimize sampling errors due to tumor heterogeneity.

It is important to grasp the number and location of trees, and measure tree structure attributes, such as tree trunk diameter and height. The accurate measurement of these parameters will lead to efficient forest resource utilization, maintenance of trees in urban cities, and feasible afforestation planning in the future. Recently, light detection and ranging (LiDAR) has been receiving considerable attention, compared with conventional manual measurement techniques. However, it is difficult to use LiDAR for widespread applications, mainly because of the costs. We propose a method for tree measurement using 360° spherical cameras, which takes omnidirectional images. For the structural measurement, the three-dimensional (3D) images were reconstructed using a photogrammetric approach called structure from motion. Moreover, an automatic tree detection method from the 3D images was presented. First, the trees included in the 360° spherical images were detected using YOLO v2. Then, these trees were detected with the tree information obtained from the 3D images reconstructed using structure from motion algorithm. As a result, the trunk diameter and height could be accurately estimated from the 3D images. The tree detection model had an F-measure value of 0.94. This method could automatically estimate some of the structural parameters of trees and contribute to more efficient tree measurement.

Fabrication methods for a 3D periodic nanostructure with excellent and unique properties for various applications, such as photonic and phononic crystals, have attracted considerable interest. Templating processes using colloidal crystals have been proposed to create nanoshell-based 3D structures over a large area with ease. However, there are technical limitations in structural design, resulting in difficulties for structural flexibility. Here, we demonstrate a combination of proximity field nanopatterning and infiltration processes using solution-derived ZnO for a nanoshell-based 3D periodic structure with high structural flexibility and controllability. A unique process of infiltration of a solution-derived material into a polymeric template prepared by a proximity field nanopatterning process achieves the fabrication of a pre-formed layer that works as a protective layer for the template and framework for the inverse structure. Subsequently, this process shows the controllability of nanoshell thickness and significant improvement in the structure height shrinkage factor (16%) compared to those of a previous non-vacuum infiltration method (34%). The proposed method offers high controllability and flexibility in the design of structural sizes, leading to further development toward nanoshell-based 3D structures for various applications including energy devices and sensors. Electronic supplementary material The online version of this article (doi:10.1186/s11671-017-2186-6) contains supplementary material, which is available to authorized users.

Background To describe the clinical set-up and evaluate the feasibility of multimodal ultrasound tomography (MUT) for breast imaging. Methods Thirty-two consecutive patients referred for breast imaging and 24 healthy volunteers underwent MUT. In the 32 patients, the examination discomfort was compared to that of mammography (n = 31), handheld ultrasound (HUS) (n = 27) and magnetic resonance imaging (MRI) (n = 4) on a scale from 1 (lowest discomfort) to 10 (highest discomfort). MUT investigation time was recorded. Findings automatically detected by MUT were correlated with conventional imaging and biopsy results. Results Breast MUT was well tolerated by all 56 participants; 55 bilateral exams were uneventful. During one exam, the digitalisation card failed and the exam was successfully repeated within three days. Mean examination discomfort was 1.6 (range = 1–5) for MUT, 1.5 (range = 1–5) for HUS, 5.3 (range = 3–7) for MRI, and 6.3 (range = 1–10) for mammography. MUT examination time was 38 ± 6 min (mean ± standard deviation). In the patients referred for breast imaging, MUT detected four lesions and indicated malignancy in three of these cases. These findings were confirmed by additional imaging and biopsy. Conclusion MUT is feasible in a clinical context considering examination time and patient acceptance. These interesting initial diagnostic findings warrant further studies.

AIMS Our aim was to evaluate the acute effects of transcatheter edge-to-edge mitral valve repair using the MitraClip device on mitral valve geometry in patients with functional mitral regurgitation (FMR). METHODS AND RESULTS Forty-two patients (age 73 years [IQ range 66.1-78.0], 55% men, 62% ischaemic FMR) with moderate-to-severe and severe FMR treated with the MitraClip were included. Three-dimensional transoesophageal echocardiography was performed prior to and immediately after MitraClip implantation. Acute changes of mitral annular and leaflet geometry were assessed with dedicated mitral modelling software. FMR less than moderate grade was achieved in 36 (86%) patients. After MitraClip implantation, the mitral annulus became more elliptical (ellipticity from 122±17% to 129±18%; p=0.04) with a non-significant reduction in anteroposterior diameter (33±6 to 32±5 mm, p=0.08). The coaptation area increased from 350 mm2 (IQ range 289-493 mm2) to 434 mm2 (IQ range 328-523 mm2, p=0.008). In particular, a larger part of the anterior mitral leaflet was included in the coaptation, leaving a smaller exposed anterior leaflet length of the A2 segment (from 27±6 mm to 25±5 mm, p

[EN] The experimental analysis of three-dimensional (3D) movement is of great importance to introduce students to knowledge of the actual physical world. However, the difficulties of collecting 3Ddatamake it little suitable for beginner physics students. In this work, we propose an experiment to analyse 3D motion in stationary and rotating systems. A projectile is launched from a rotating platform. The tracking of the projectile is carried out with the assistance of a stereoscopic camera and simplified object tracking techniques. The experiment can be modelled through the well-known transformation equations between an inertial reference system and a non-inertial one with constant angular velocity. The simplicity of the method and the agreement between the experimental data and the theoretical model make the experiment accessible to undergraduate physics students. In this way, they can easily measure a 3D movement and verify its theoretical equations. © 2011 IOP Publishing Ltd.

For synthetic aperture radars, it is difficult to achieve forward-looking and staring imaging with high resolution. Fortunately, terahertz coded-aperture imaging (TCAI), an advanced radar imaging technology, can solve this problem by producing various irradiation patterns with coded apertures. However, three-dimensional (3D) TCAI has two problems, including a heavy computational burden caused by a large-scale reference signal matrix, and poor resolving ability at low signal-to-noise ratios (SNRs). This paper proposes a 3D imaging method based on geometric measures (GMs), which can reduce the computational burden and achieve high-resolution imaging for low SNR targets. At extremely low SNRs, it is difficult to detect the range cells containing scattering information with an ordinary range profile. However, this difficulty can be overcome through GMs, which can enhance the useful signal and restrain the noise. By extracting useful data from the range profile, target information in different imaging cells can be simultaneously reconstructed. Thus, the computational complexity is distinctly reduced when the 3D image is obtained by combining reconstructed 2D imaging results. Based on the conventional TCAI (C-TCAI) model, we deduce and build a GM-based TCAI (GM-TCAI) model. Compared with C-TCAI, the experimental results demonstrate that GM-TCAI achieves a more impressive performance with regards to imaging ability and efficiency. Furthermore, GM-TCAI can be widely applied in close-range imaging fields, for instance, medical diagnosis, nondestructive detection, security screening, etc.

As a promising radar imaging technique, terahertz coded-aperture imaging (TCAI) can achieve high-resolution, forward-looking, and staring imaging by producing spatiotemporal independent signals with coded apertures. However, there are still two problems in three-dimensional (3D) TCAI. Firstly, the large-scale reference-signal matrix based on meshing the 3D imaging area creates a heavy computational burden, thus leading to unsatisfactory efficiency. Secondly, it is difficult to resolve the target under low signal-to-noise ratio (SNR). In this paper, we propose a 3D imaging method based on matched filtering (MF) and convolutional neural network (CNN), which can reduce the computational burden and achieve high-resolution imaging for low SNR targets. In terms of the frequency-hopping (FH) signal, the original echo is processed with MF. By extracting the processed echo in different spike pulses separately, targets in different imaging planes are reconstructed simultaneously to decompose the global computational complexity, and then are synthesized together to reconstruct the 3D target. Based on the conventional TCAI model, we deduce and build a new TCAI model based on MF. Furthermore, the convolutional neural network (CNN) is designed to teach the MF-TCAI how to reconstruct the low SNR target better. The experimental results demonstrate that the MF-TCAI achieves impressive performance on imaging ability and efficiency under low SNR. Moreover, the MF-TCAI has learned to better resolve the low-SNR 3D target with the help of CNN. In summary, the proposed 3D TCAI can achieve: (1) low-SNR high-resolution imaging by using MF; (2) efficient 3D imaging by downsizing the large-scale reference-signal matrix; and (3) intelligent imaging with CNN. Therefore, the TCAI based on MF and CNN has great potential in applications such as security screening, nondestructive detection, medical diagnosis, etc.

PurposeThe purpose of this paper is to present in‐depth numerical modelling of heat and mass exchange in industrial induction channel furnace (ICF).Design/methodology/approachThe turbulent heat and mass exchange in the melt is calculated using a three‐dimensional (3D) electromagnetic model and a 3D transient large eddy simulation method. The simulation model has been verified by flow velocity and temperature measurements, which were carried out using an industrial sized channel inductor operating with Wood's metal as a low temperature model melt.FindingsThe ICF is well‐established for melting, holding and casting in the metallurgical industry. But there are still open questions regarding the heat and mass exchange in the inductor channel itself and between the channel and the melt bath. Different new designed channel geometries have been investigated numerically in order to find an optimized shape of the channel, which leads to an improved heat and mass transfer.Originality/valueLong‐term computations for the industrial ICF have been performed. Low frequency oscillations of the temperature maximum and its position in the ICF channel are considered.

The paper presents a new three-dimensional (3D) cooperative guidance approach by the receding horizon control (RHC) technique. The objective is to coordinate the impact time of a group of interceptor missiles against the stationary target. The framework of a distributed RHC scheme is developed, in which each interceptor missile is assigned its own finite-horizon optimal control problem (FHOCP) and only shares the information with its neighbors. The solution of the local FHOCP is obtained by the constrained particle swarm optimization (PSO) method that is integrated into the distributed RHC framework with enhanced equality and inequality constraints. The numerical simulations show that the proposed guidance approach is feasible to implement the cooperative engagement with satisfied accuracy of target capture. Finally, the computation efficiency of the distributed RHC scheme is discussed in consideration of the PSO parameters, control update period and prediction horizon.

Perovskite solar cells (PSCs) are promising alternatives toward clean energy because of their high-power conversion efficiency (PCE) and low materials and processing cost. However, their poor stability under operation still limits their practical applications. Here we design an innovative approach to control the surface growth of a low dimensional perovskite layer on top of a bulk three-dimensional (3D) perovskite film. This results in a structured perovskite interface where a distinct layered low dimensional perovskite is engineered on top of the 3D film. Structural and optical properties of the stack are investigated and solar cells are realized. When embodying the low dimensional perovskite layer, the photovoltaic cells exhibit an enhanced PCE of 20.1% on average, when compared to pristine 3D perovskite. In addition, superior stability is observed: the devices retain 85% of the initial PCE stressed under one sun illumination for 800 hours at 50 1 C in an ambient environment.