bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accuracy of position tracking and fabrication of thin diameter sensor
Authors: Chen Xiangyan , Zhang Yanan , Qian Jinwu , Shen Linyong 
Published: January 2021

Abstract
The shape reconstruction of medical surgical instruments in robotic laryngeal surgery, positioning a needle to puncture a breast tumour, shape display during intestinal endoscopy, and positioning a cardiac vascular catheter, is affected by not only the end position and the shape reconstruction accuracy but also the diameter and curvature of the sensor owing to the limited application space. A sensor with a substrate is manufactured by pasting a fibre Bragg grating (FBG) on the surface of nitinol wire. The measuring range of the substrate is improved by applying a certain preload before glue injection. The sensor has the advantages of being less prone to breakage and greater durability but has a limited bending curvature and diameter. In minimally invasive surgery, the curvature of the body cavity is complex, and the space is narrow, and thus the FBG sensor must have a smaller diameter and good bending curvature. The present paper proposes a method of filling and encapsulating a small-diameter substrate sensor. A substrate-less sensor with a diameter of 1.5 mm and sensing length of 200 mm is encapsulated by improving the packaging positioning piece, current glue injection method, and packaging process. Four FBGs with two grating points for each fibre are distributed at 90° to each other, and four measuring points are obtained by wavelength division multiplexing and space division multiplexing. A calibration and shape reconstruction experiment is carried out for the shape sensor, while a packaging error compensation calibration method is introduced to improve the precision of shape reconstruction. Results of a two-dimensional experiment show that the shape reconstruction accuracy of the sensor on the plane bending is 2.71%. In a three-dimensional spiral experiment, the measurement accuracy of FBG shape sensor out-of-plane bending is 3.42%.
Facile synthesis of 2D α-MnO2 nanosheets for the removal of heavy metal ions
Authors: Li Hao , Gui Lin , Gao Zhanyang , Ren Feipeng , Zhang Honglei , Peng Ruichao 
Published: January 2021

Abstract
Removal of heavy metal ions (HMIs) has attracted great attentions due to the fact that they have serious effect on environment and human beings. Manganese oxide (MnO2) was widely used as absorbent for the HMIs removal on account of its low-cost, eco-friendly and biocompatibility. The modification of morphological and structure is recognized as the effective route to improve the adsorption capacity. In this work, 2D α-MnO2 nanosheets were synthesized by hydrothermal method with Al3+ additive. With the merits of high specific surface area, high dispersity in aqueous solution and abundant surface defects, 2D α-MnO2 nanosheets exhibited excellent HMIs adsorption performance. The maximum adsorption capacity of 2D α-MnO2 nanosheets reached 1.604 mmol g−1 (Pb2+) and 0.813 mmol g−1 (Cd2+), respectively and can maintain stable after five cycles. Besides, the established adsorption kinetics fitted well with pseudo-second-order adsorption kinetics model. Based on the above results, 2D α-MnO2 is efficient for the removal of HMIs and possesses remarkable practical application potential.
Strong adsorption, catalysis and lithiophilic modulation of carbon nitride for lithium/sulfur battery
Authors: Ji Lei , Jia Yongfeng , Wang Xia , Duan Limei , Li Weishan , Liu Jinghai , Zhang Yuegang 
Published: January 2021

Abstract
Lithium/sulfur (Li/S) batteries have emerged as one of the most promising next-generation energy storage systems with advantages of high theoretical energy density, low cost and environmental friendliness. However, problems regarding to severe shuttle effect of soluble polysulfide, poor electronic/ionic conductor of solid charged/discharged products (S8 and Li2S), and fatal swell of volume along with the growth of Li dendrites greatly deteriorate the sulfur utilization and capacity retention during extended charge–discharge cycles. With advantages of high nitrogen content, lithiophilic modulation and tunable charge density and charge transfer, carbon nitride (g-C3N4) has played a positive role in restricting the shuttle effects and dendrite formation. This minireview mainly discusses these research achievements of g-C3N4 in Li/S batteries, aiming to provide a basic understanding and direct guidance for further research and development of functionalized g-C3N4 materials in electrical energy storage. The two-dimensional (2D) structure of g-C3N4 with abundant hierarchical pores improves its accommodation capacity for sulfur by effectively confining the lithium polysulfides (LiPSs) into the pores, and provides favorable channels for ion diffusion. The rich nitrogen and carbon defects further offer more active sites for strongly adsorbing LiPSs and bridge electron transfer pathway at atomic scale for catalytic reactions to accelerate redox kinetics of Li/S conversion chemistry. Moreover, the features of lithiophilic wettability, high adsorption energy and densely distributed lithiophilic N of g-C3N4 provide a large number of adhesive sites for lithium cation (Li+) and disperse the nucleation sites to enable uniform nucleation and deposition of Li on the anode surface and to suppress formation and growth of Li dendrites. Finally, the g-C3N4 also effectively regulates the wettability between Li anode and solid inorganic electrolyte, and reduces the crystallinity of solid polymer electrolyte to enhance the Li+ migration ability and ionic conductivity.
Crystallinity-dependent device characteristics of polycrystalline 2D n = 4 Ruddlesden–Popper perovskite photodetectors
Authors: Kim Junwoo , Lee Woocheol , Cho Kyungjune , Ahn Heebeom , Lee Jonghoon , Baek Kyeong-Yoon , Kim Jae-Keun , Kang Keehoon , Lee Takhee 
Published: January 2021

Abstract
Ruddlesden–Popper (RP) perovskites have attracted a lot of attention as the active layer for optoelectronic devices due to their excellent photophysical properties and environmental stability. Especially, local structural properties of RP perovskites have shown to play important roles in determining the performance of optoelectronic devices. Here, we report the photodetector performance variation depending on the crystallinity of n = 4 two-dimensional (2D) RP perovskite polycrystalline films. Through controlling the solvent evaporation rate, 2D RP perovskite films could be tuned between highly- and randomly-orientated phases. We investigated how different factors related to the film crystallinity are reflected in the variation of photodetector performances by considering grain boundary and low energy edge state effects in n = 4 RP perovskites. Better understanding the interplay between these factors that govern the photophysical properties of the devices would be beneficial for designing high-performance RP perovskite-based optoelectronic devices.
H2S sensing for breath analysis with Au functionalized ZnO nanowires
Authors: Kaiser Angelika , Torres Ceja Erick , Liu Yujia , Huber Florian , Müller Raphael , Herr Ulrich , Thonke Klaus 
Published: January 2021

Abstract
This work presents a H2S selective resistive gas sensor design based on a chemical field effect transistor (ChemFET) with open gate formed by hundreds of high temperature chemical vapour deposition (CVD) grown zinc oxide nanowires (ZnO NW). The sensing ability of pristine ZnO NWs and surface functionalized ZnO NWs for H2S is analysed systematically. ZnO NWs are functionalized by deposition of discontinuous gold (Au) nanoparticle films of different thicknesses of catalyst layer ranging from 1 to 10 nm and are compared in their gas sensing properties. All experiments were performed in a temperature stabilized small volume compartment with adjustable gas mixture at room temperature. The results allow for a well-founded understanding of signal-to-noise ratio, enhanced response, and improved limit of detection due to the Au functionalisation. Comprehension and controlled application of the beneficial effects of Au catalyst on ZnO NWs allow for the detection of very low H2S concentrations down to 10 ppb, and a theoretically estimated 500 ppt in synthetic air at room temperature.
Quantitative estimation of atom-scaled ripple structure using transmission electron microscopy images
Authors: Xie Lilin , Oshima Yoshifumi 
Published: January 2021

Abstract
Atom-scaled ripple structure can be intrinsically formed because of thermal instability or induced stress in graphene or two-dimensional (2D) materials. However, it is difficult to estimate the period, amplitude, and shape of such a ripple structure. In this study, by applying the geometrical phase analysis method to atomically resolved transmission electron microscopy images, we demonstrate that the atom-scaled ripple structure of MoS2 nanosheet can be quantitatively analyzed at the subnanometer scale. Furthermore, by analyzing the observed ripple structure of the MoS2 nanosheet, we established that it is inclined by approximately 7.1° from the plane perpendicular to the incident electron beam; it had 5.5 and 0.3 nm in period and amplitude, respectively. For quantitative estimation of ripple structure, our results provide an effective method that contributes to a better understanding of 2D materials in the sub-nanometre scale.
An oblique projection modification technique (OPMT) for fast multispectral CT reconstruction
Authors: Zhao Shusen , Pan Huiying , Zhang Weibin , Xia Dimeng , Zhao Xing 
Published: January 2021

Abstract
In x-ray multispectral (or photon-counting) computed tomography (MCT), the object of interest is scanned under multiple x-ray spectra, and it can acquire more information about the scanned object than conventional CT, in which only one x-ray spectrum is used. The obtained polychromatic projections are utilized to perform material-selective and energy-selective image reconstruction. Compared with the conventional single spectral CT, MCT has a superior material distinguishability. Therefore, it has wide potential applications in both medical and industrial areas. However, the nonlinearity and ill condition of the MCT problem make it difficult to get high-quality and fast convergence of images for existing MCT reconstruction algorithms. In this paper, we proposed an iterative reconstruction algorithm based on an oblique projection modification technique (OPMT) for fast basis material decomposition of MCT. In the case of geometric inconsistency, along the current x-ray path, the oblique projection modification direction not only relates to the polychromatic projection equation of the known spectrum, but it also comprehensively refers to the polychromatic projection equation information of the unknown spectra. Moreover, the ray-by-ray correction makes it applicable to geometrically consistent projection data. One feature of the proposed algorithm is its fast convergence speed. The OPMT considers the information from multiple polychromatic projection equations, which greatly speeds up the convergence of MCT reconstructed images. Another feature of the proposed algorithm is its high flexibility. The ray-by-ray correction will be suitable for any common MCT scanning mode. The proposed algorithm is validated with numerical experiments from both simulated and real data. Compared with the ASD-NC-POCS and E-ART algorithms, the proposed algorithm achieved high-quality reconstructed images while accelerating the convergence speed of them.
New target volume delineation and PTV strategies to further personalise radiotherapy
Authors: Bernstein David , Taylor Alexandra , Nill Simeon , Oelfke Uwe 
Published: January 2021

Abstract
Target volume delineation uncertainty (DU) is arguably one of the largest geometric uncertainties in radiotherapy that are accounted for using planning target volume (PTV) margins. Geometrical uncertainties are typically derived from a limited sample of patients. Consequently, the resultant margins are not tailored to individual patients. Furthermore, standard PTVs cannot account for arbitrary anisotropic extensions of the target volume originating from DU. We address these limitations by developing a method to measure DU for each patient by a single clinician. This information is then used to produce PTVs that account for each patient’s unique DU, including any required anisotropic component. We do so using a two-step uncertainty evaluation strategy that does not rely on multiple samples of data to capture the DU of a patient’s gross tumour volume (GTV) or clinical target volume. For simplicity, we will just refer to the GTV in the following. First, the clinician delineates two contour sets; one which bounds all voxels believed to have a probability of belonging to the GTV of 1, while the second includes all voxels with a probability greater than 0. Next, one specifies a probability density function for the true GTV boundary position within the boundaries of the two contours. Finally, a patient-specific PTV, designed to account for all systematic errors, is created using this information along with measurements of the other systematic errors. Clinical examples indicate that our margin strategy can produce significantly smaller PTVs than the van Herk margin recipe. Our new radiotherapy target delineation concept allows DUs to be quantified by the clinician for each patient, leading to PTV margins that are tailored to each unique patient, thus paving the way to a greater personalisation of radiotherapy.
U-Net-based approach for automatic lung segmentation in electrical impedance tomography
Authors: Ko Yen-Fen , Cheng Kuo-Sheng 
Published: January 2021

Abstract

Objective. Electrical impedance tomography (EIT) is a non-invasive technique that constitutes a promising tool for real-time imaging and long-term monitoring of the ventilation distribution at bedside. However, clinical monitoring and diagnostic evaluations depend on various methods to assess ventilation-dependent parameters useful for ventilation therapy. This study develops an automatic, robust, and rapidly accessible method for lung segmentation that can be used to define appropriate regions-of-interest (ROIs) within EIT images. Approach. To date, available methods for patients with defected lungs have the disadvantage of not being able to identify lung regions because of their poor ventilation responses. Furthermore, the challenges related to the identification of lung areas in EIT images are attributed to the low spatial resolution of EIT. In this study, a U-Net-based automatic lung segmentation model is used as a postprocessor to transform the original EIT image to a lung ROI image and refine the inherent conductivity distribution of the original EIT image. The trained U-Net network is capable of performing an automatic segmentation of conductivity changes in EIT images without requiring prior information. Main results. The experimental design of this study was based on a finite element method (FEM) phantom used to assess the feasibility and effectiveness of the proposed method, and evaluation of the trained models on the test dataset was performed using the Dice similarity coefficient (DSC) and the mean absolute error (MAE). The FEM experimental results yielded values of 0.0065 for MAE, and values >0.99 for DSC in simulations. Significance. The use of a deep-learning-based approach attained automatic and convenient segmentation of lung ROIs into distinguishable images, which represents a direct benefit for regional lung ventilation-dependent parameter extraction and analysis. However, further investigations and validation are warranted in real human datasets with different physiology conditions with CT cross-section dataset to refine the suggested model.
Estimating blood flow velocity using time-resolved 3D angiography and a derived physical law of contrast media
Authors: Chen Ko-Kung , Lin Chung-Jung , Guo Wan-Yuo , Chu Wei-Fa , Wu Yu-Te 
Published: January 2021

Abstract

Objective. Four-dimensional (4D) digital subtraction angiography (DSA) offers a method for evaluating hemodynamics. It is, however, unclear how the delivered contrast medium interacts with the physiological blood flow, and how hemodynamic information may be inferred from the mixture of the contrast medium and blood. In this study, we present a theoretical explanation of contrast dynamics, and an accompanying algorithm for estimating blood flow velocity. Approach. We retrospectively recruited 23 patients who underwent both 4D DSA and magnetic resonance (MR) phase-contrast imaging. The 4D DSA-reconstructed contrast dynamics were first studied for the internal carotid arteries. Using physical laws governing fluid motion within a curved tube, we showed that the reconstructed contrast dynamics obeyed a simple advection equation. We then proposed an algorithm for estimating the contrast dynamics using angiographic data, and subsequently estimated the axial blood flow velocity using an advection equation. Main results. The estimated velocities were compared using three techniques: the Fourier technique, Lin’s method, and MR phase contrast. Testing with noise-corrupted artificial data showed that the proposed algorithm was noise resistant. The velocities of 23 patients computed by 4D DSA using the proposed algorithm showed a moderate correlation with the MR phase contrast (r = 0.61), and good correlations with the other two techniques (r = 0.75 and r = 0.72). Significance. The proposed algorithm and has been applied to blood vessel segments with poor signal-to-noise ratios and axial lengths of less than 3 cm, and has a physical basis for computing axial flow velocities using an advection equation. The results of the proposed algorithm are consistent with existing methods.
Solution-based CdS thin film transistors with low temperature-processed Al2O3-GPTMS-PMMA as hybrid dielectric gate
Authors: Meza-Arroyo J , Chandra Sekhar Reddy K , Syamala Rao M G , Garibay-Martínez F , de Urquijo-Ventura M S , Ramírez-Bon R 
Published: January 2021

Abstract
Herein, we report the low-temperature fabrication process and the electrical response of n-type cadmium sulfide (CdS)-based thin-film transistors (TFTs) with an Al2O3-GPTMS-polymethylmethacrylate (PMMA) hybrid dielectric gate. The TFTs with bottom-gate structure were assembled on ITO (indium-tin-oxide)-coated glass substrates employing solution processes for the deposition of both the dielectric gate and semiconductor layers. The hybrid dielectric layers were deposited by the sol-gel process and subsequently annealed at 150 °C. The FTIR and XPS analysis of the hybrid films demonstrated a proper link between Al2O3 and PMMA through the cross-linking agent 3-glycidoxy(propyltrimethoxysilane) silane (GPTMS). The surface characteristics were obtained by contact angle and atomic force microscope studies, the results show that the surface of hybrid films displays a hydrophobic behavior with a smooth surface. The CdS active layer was deposited on the hybrid dielectric gate at room temperature by a simple photochemical bath deposition using a 313 nm UV lamp. The CdS-TFTs showed outstanding electrical performance with a low threshold voltage of 1.3 V, I
ON
/I
OFF of 104, subthreshold swing of 440 mV dec−1, and remarkable high mobility value of 64.4 cm2 V−1 s−1. Ultimately, the feature of these completely solution-based CdS TFTs is the maximum processing temperature of 150 °C, and the findings of this study are very promising for potential low-cost solution-processed TFTs.
Wearable pressure sensor based on MXene/single-wall carbon nanotube film with crumpled structure for broad-range measurements
Authors: Fan Zhihong , Zhang Lei , Tan Qiulin , Yao Xue , Lin Baimao , Wang Ya , Xiong Jijun 
Published: January 2021

Abstract
High-performance flexible pressure sensors are attracting great interest owing to their potential applications for electronic skins, human–machine interfaces, and biomedical diagnostics. However, there remain significant challenges for the fabrication of low-cost and high-sensitivity sensors. Here, we report the preparation of Ti3C2T
x
MXene/single-wall carbon nanotube (SWNT) composite films through vacuum-assisted filtration followed by thermal shrinkage. SWNTs can effectively prevent MXenes from stacking and improve the electrical performance of the films. The films are used as a flexible piezoresistive sensor for pressures ranging from 33 Pa to 130 kPa. And experimental test results indicate that the fabricated pressure sensors have high sensitivity (116.15 kPa−1 below 40 kPa and 12.7 kPa−1 at 40–130 kPa), a fast response time of 13 ms, and long-term stability over 6000 periods. The sensor can be used to monitor human physiological signals, such as finger movements, voice detection, and wrist pulse in real-time. Moreover, a 4 × 4 sensor array was successfully applied in the pressure distribution mapping of different objects, indicating that the pressure sensor can be applied in electronic skin, medical devices, and other wearable devices.
Control of rejection frequency and density of output spectrum by programming nonuniform two channels with ternary fluidic system
Authors: Park Eiyong , Lim Sungjoon 
Published: January 2021

Abstract
The growth of multi-functional wireless systems has made selecting the operation frequency and rejecting unwanted frequencies very difficult because of the interferences in dense spectra. Compared to conventional electronic tuning devices, microfluidic channels have great potential because of the greater design freedom and fewer parasitic effects. Previously, single or uniform microfluidic channels have been used for microwave sensors, antennas, or filters. In this study, a rejection frequency control filter was constructed by programming two nonuniform channels with a ternary fluidic system. To obtain two nonuniform channels with a wide tuning range, a novel defected ground cavity structure was designed. When three different fluids are used as ‘0’, ‘1’, and ‘2’ inputs for the ternary fluidic system, it outputs nine different rejection frequencies. The density of the output spectrum can be controlled by designing either uniform or nonuniform channels in the proposed fluidic system. For instance, uniform channels produce sparse frequency channels between 1.95 and 3.55 GHz. By contrast, the nonuniform channels produce dense and successive frequency spectra ranging from 2.5 to 3.32 GHz. Thus, the tuning range of uninform channels is wider than that of nonuniform channels.
Heating and de-icing function in conductive concrete and cement paste with the hybrid addition of carbon nanotubes and graphite products
Authors: Farcas C , Galao O , Navarro R , Zornoza E , Baeza F J , Del Moral B , Pla R , Garcés P 
Published: January 2021

Abstract
This paper aims to study the viability of conductive cement paste and conductive concrete with the hybrid addition of carbon nanotubes (CNT) and graphite powder (GP) as a self-heating material for heating, ice formation prevention and de-icing in pavements. Different heating tests, ice-preventing tests and de-icing tests were performed with cement paste and concrete specimens. Results confirm that the conductive cement composites studied, with the addition of 1% CNT + 5% GP, exhibited heating, de-icing and ice-prevention properties, when applying constant AC/DC voltages between the two end sides of each specimen, with relatively low energy consumption. The main contribution of this work is to achieve a sufficient conductivity level for the development of the heating and de-icing function using this hybrid addition in concrete, which has not been used so far, in order to be applied in real concrete structures.