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The use of a two-dimensional (2D) van der Waals (vdW) metal-semiconductor (MS) heterojunction as an efficient cold source (CS) has recently been proposed as a promising approach in the development of steep-slope field-effect transistors (FETs). In addition to the selection of source materials with linearly decreasing density-of-states-energy relations (D(E)s), in this study, we further verified, by means of a computer simulation, that a 2D semiconductor-semiconductor combination could also be used as an efficient CS. As a test case, a HfS2/MoTe2 FET was studied. It was found that MoTe2 can be spontaneously p-type-doped by interfacing with n-doped HfS2, resulting in a truncated decaying hot-carrier density with an increasing p-type channel barrier. Compared to the conventional MoTe2 FET, the subthreshold swing (SS) of the HfS2/MoTe2 FET can be significantly reduced to below 60 mV/decade, and the on-state current can be greatly enhanced by more than two orders of magnitude. It was found that there exists a hybrid transport mechanism involving the cold injection and the tunneling effect in such a p- and n-type HfS2/MoTe2 FET, which provides a new design insight into future low-power and high-performance 2D electronics from a physical point of view. [ABSTRACT FROM AUTHOR]

2D semiconductors, which have been the candidate channel materials for next‐generation field‐effect transistors (FETs), are now reaching the fundamental limits to what they can offer for higher driving current and switching speed. Low carrier mobility and correspondingly high effective mass hinder such materials to become the ideal electron transport systems. Herein, the electronic and transport properties of strained α‐GeTe are studied for low‐power transistor applications. It is found that monolayer α‐GeTe exhibits a sensitive strain response and undergoes an indirect‐to‐direct bandgap transition at about 2% of tensile uniaxial strain in the zigzag direction, significantly decreasing the electron effective mass and improving electron mobility. In addition, applying tensile strain in the armchair direction can effectively reduce the band‐edge energy of the conduction band minimum (CBM), suggesting that strain can reduce the energy barrier of electrons. These favorable strain responses considerably impact the device performance where both steeper subthreshold swing (SS) and higher on‐state currents can be achieved in monolayer α‐GeTe‐based metal–oxide–semiconductor FETs (MOSFETs). It is hoped that such strain benefits can provide an effective way to modulate the properties of α‐GeTe and finally enhance the device performance. [ABSTRACT FROM AUTHOR]

Scoliosis is a spinal deformation in which the spine takes a lateral curvature, generating an angle in the coronal plane. The conventional method for detecting scoliosis is measurement of the Cobb angle in spine images obtained by anterior X-ray scanning. Ultrasound imaging of the spine is found to be less ionising than traditional radiographic modalities. For posterior ultrasound scanning, alternate indices of the spinous process angle (SPA) and ultrasound curve angle (UCA) were developed and have proven comparable to those of the traditional Cobb angle. In SPA, the measurements are made using the spinous processes as an anatomical reference, leading to an underestimation of the traditionally used Cobb angles. Alternatively, in UCA, more lateral features of the spine are employed for measurement of the main thoracic and thoracolumbar angles; however, clear identification of bony features is required. The current practice of UCA angle measurement is manual. This research attempts to automate the process so that the errors related to human intervention can be avoided and the scalability of ultrasound scoliosis diagnosis can be improved. The key objective is to develop an automatic scoliosis diagnosis system using 3-D ultrasound imaging. The novel diagnosis system is a three-step process: (i) finding the ultrasound spine image with the most visible lateral features using the convolutional RankNet algorithm; (ii) segmenting the bony features from the noisy ultrasound images using joint spine segmentation and noise removal; and (iii) calculating the UCA automatically using a newly developed centroid pairing and inscribed rectangle slope method. The proposed method was evaluated on 109 patients with scoliosis of different severity. The results obtained had a good correlation with manually measured UCAs ( R 2 = 0.9784 for the main thoracic angle and R 2 = 0.9671 for the thoracolumbar angle) and a clinically acceptable mean absolute difference of the main thoracic angle (2.82 ± 2.67°) and thoracolumbar angle (3.34 ± 2.83°). The proposed method establishes a very promising approach for enabling the applications of economic 3-D ultrasound volume projection imaging for mass screening of scoliosis. [ABSTRACT FROM AUTHOR]

Purpose: Evidence suggests that social capital in medical and health institutions is associated with the job satisfaction of medical staff. We examined the relationship between the social capital of Primary Healthcare Institutions (PHI) and the job satisfaction of pharmacists within it. Materials and Methods: From August 24 to September 1, 2021, we visited a total of 253 PHIs in 31 provinces of China. The social capital of healthcare organizations reported by employees (SOCAPO-E) scale was used to measure the social capital level of PHIs. And the Minnesota short-form job satisfaction scale was used to obtain pharmacists' job satisfaction. We employed multiple linear regression to explore the relationship between the social capital of PHI and pharmacists' job satisfaction. We also examined the effects of pharmacists' individual characteristics and job-related factors on pharmacists' job satisfaction. Results: It was statistically significant that the higher the social capital stock of PHI, the higher the job satisfaction level of pharmacists becomes. In addition, the regression analysis revealed that work hours, employment form, license acquired condition, disputes with patients and training frequency were significantly associated with the job satisfaction of pharmacists in PHI. Conclusion: Social capital in PHI has a significant impact on pharmacists' job satisfaction, suggesting that investing in social capital in PHI is a valuable investment in China. Furthermore, trust, which can be divided into affective trust and cognitive trust, and reciprocity are vital to the fulfillment of pharmacists' job satisfaction as core elements of social capital. [ABSTRACT FROM AUTHOR]

• Established a dataset for spine segmentation of ultrasound scoliosis images. • Build a dual-task spine transverse vertebrae segmentation network based on U-Net. • An auxiliary shape regularization task is used to assist the semantic segmentation. • Fused the features of two-stream to enhance their representation abilities. • Imported ASPP structure which also fused features of auxiliar network. • Obtained a promising result and are the first team to segment them automatically. 3D ultrasound imaging has become one of the common diagnosis ways to assess scoliosis since it is radiation-free, real-time, and low-cost. Spine curvature angle measurement is an important step to assess scoliosis precisely. One way to calculate the angle is using the vertebrae features of the 2-D coronal images to identify the most tilted vertebrae. To do the measurement, the segmentation of the transverse vertebrae is an important step. In this paper, we propose a dual-task ultrasound transverse vertebrae segmentation network (D-TVNet) based on U-Net. First, we arrange an auxiliary shape regularization network to learn the contour segmentation of the bones. It improves the boundary segmentation and anti-interference ability of the U-Net by fusing some of the features of the auxiliary task and the main task. Then, we introduce the atrous spatial pyramid pooling (ASPP) module to the end of the down-sampling stage of the main task stream to improve the relative feature extraction ability. To further improve the boundary segmentation, we extendedly fuse the down-sampling output features of the auxiliary network in the ASPP. The experiment results show that the proposed D-TVNet achieves the best dice score of 86.68% and the mean dice score of 86.17% based on cross-validation, which is an improvement of 5.17% over the baseline U-Net. An automatic ultrasound spine bone segmentation network with promising results has been achieved. [ABSTRACT FROM AUTHOR]

• Since recent cascade MRI reconstruction models deeply rely on the known sample mask, we designed a specific network to estimate the mask from sampled k-space data. This network solved the mask prior needed problem. • We rethink the MRI reconstruction model as a k-space inpainting task and proposed a dualdomain network to extract features in both the k-space domain and image domain to inpaint the MR image. • Combining these two networks, we presented a blind MRI reconstruction model named dual-task dual-domain network. MRI reconstruction is the key technology to accelerate MR acquisition. Recent cascade models have gained satisfactory results, however, they deeply rely on the known sample mask, which we call it mask prior. To restore the MR image without mask prior, we designed an auxiliary network to estimate the mask from sampled k-space data. Experimentally, the sample mask can be completely estimated by the proposed network and be used to input to the cascade models. Moreover, we rethink the MRI reconstruction model as a k-space inpainting task. A dual-domain cascade network, which utilized partial convolutional layers to inpaint features in k-space, was presented to restore the MR image. Without the mask prior, our blind reconstruction model demonstrates the best reconstruction ability in both 4x acceleration and 8x acceleration. [ABSTRACT FROM AUTHOR]

• Considers the selection of the ultrasound spine images with large number of similarities as a ranking problem. • Selects the best image by ranking them in sequence. • Designs a specific CNN architecture for the feature extraction to replace the artificial neural network in the conventional RankNet. • Adopts the hinge loss function rather than the cross-entropy loss function in the conventional RankNet, which has more discriminating ability when the estimated output scores of two images are very close. Periodic inspection and assessment are important for scoliosis patients. 3D ultrasound imaging has become an important means of scoliosis assessment as it is a real-time, cost-effective and radiation-free imaging technique. With the generation of a 3D ultrasound volume projection spine image using our Scolioscan system, a series of 2D coronal ultrasound images are produced at different depths with different qualities. Selecting a high quality image from these 2D images is the crucial task for further scoliosis measurement. However, adjacent images are similar and difficult to distinguish. To learn the nuances between these images, we propose selecting the best image automatically, based on their quality rankings. Here, the ranking algorithm we use is a pairwise learning-to-ranking network, RankNet. Then, to extract more efficient features of input images and to improve the discriminative ability of the model, we adopt the convolutional neural network as the backbone due to its high power of image exploration. Finally, by inputting the images in pairs into the proposed convolutional RankNet, we can select the best images from each case based on the output ranking orders. The experimental result shows that convolutional RankNet achieves better than 95.5% top-3 accuracy, and we prove that this performance is beyond the experience of a human expert. [ABSTRACT FROM AUTHOR]

Computer-aided algorithm plays an important role in disease diagnosis through medical images. As one of the major cancers, lung cancer is commonly detected by computer tomography. To increase the survival rate of lung cancer patients, an early-stage diagnosis is necessary. In this paper, we propose a new structure, multi-level cross residual convolutional neural network (ML-xResNet), to classify the different types of lung nodule malignancies. ML-xResNet is constructed by three-level parallel ResNets with different convolution kernel sizes to extract multi-scale features of the inputs. Moreover, the residuals are connected not only with the current level but also with other levels in a crossover manner. To illustrate the performance of ML-xResNet, we apply the model to process ternary classification (benign, indeterminate, and malignant lung nodules) and binary classification (benign and malignant lung nodules) of lung nodules, respectively. Based on the experiment results, the proposed ML-xResNet achieves the best results of 85.88% accuracy for ternary classification and 92.19% accuracy for binary classification, without any additional handcrafted preprocessing algorithm. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials have received significant attention for their potential use in next-generation electronics, particularly in nonvolatile memory and neuromorphic computing. This is due to their simple metal–insulator–metal (MIM) sandwiched structure, excellent switching performance, high-density capability, and low power consumption. In this work, using comprehensive material simulations and device modeling, the thinnest monolayer hexagonal boron nitride (h-BN) atomristor is studied by using a MIM configuration with Ta electrodes. Our first-principles calculations predicted both a high resistance state (HRS) and a low resistance state (LRS) in this device. We observed that the presence of van der Waals (vdW) gaps between the Ta electrodes and monolayer h-BN with a boron vacancy (VB) contributes to the HRS. The combination of metal electrode contact and the adsorption of Ta atoms onto a single VB defect (TaB) can alter the interface barrier between the electrode and dielectric layer, as well as create band gap states within the band gap of monolayer h-BN. These band gap states can shorten the effective tunneling path for electron transport from the left electrode to the right electrode, resulting in an increase in the current transmission coefficient of the LRS. This resistive switching mechanism in monolayer h-BN atomristors can serve as a theoretical reference for device design and optimization, making them promising for the development of atomristor technology with ultra-high integration density and ultra-low power consumption. [ABSTRACT FROM AUTHOR]

• Dual source λET model was improved for film mulched cropland with shallow groundwater. • Ignoring film mulching leads to overestimation of λE and then λET. • Responses of the resistances in SW model to λET and its components were quantified. • Average T/ET during maize growing season was as high as 0.78–0.84. • Path analysis revealed the dominated effects of Hc and WTD on maize λET. Evapotranspiration (ET) is a key link in terrestrial water cycle and influenced by complex environmental factors in cropland. Accurate assessment of crop ET over heterogeneous underlying surfaces remains challenging. In this study, the dual source Shuttleworth-Wallace (SW) model was modified to estimate λET (latent heat corresponding to ET) through incorporating the effects of film mulching and shallow groundwater. λET and latent heat from transpiration (λT) were measured in a maize field in northwest China during 2017 and 2018 to assess the performance of the original (SW) and modified (SWM) models. Results indicate that the overestimation of latent heat from soil evaporation (λE) due to ignoring film mulching could be obviously mitigated by SWM. Besides, considering capillary rise from shallow groundwater in SWM improved not only λET estimates but also the accuracy of canopy resistance parameter. The SWM model outperformed the SW model that the slopes of fitting lines for λET and λT increased from 0.60 to 0.79 to 0.77–0.99 at daily scale and Nash-Sutcliffe Efficiency coefficient exceeded 0.86. Relative error and RMSE were decreased to below 0.15 and 19.88 W m−2, respectively. The estimations of λET and λT by SWM were also improved at hourly scale. Seasonal variation and partition of λET between two years were comparable and average T/ET for the entire growing season was about 78 %-84 %, which was largest at the heading stage. Path analysis on the responses of λET to the environmental factors recognized the greatest direct effect of crop height or leaf area index, and identified the significantly direct control of shallow groundwater on λT in this area. The study presented an improved dual source model to better quantify λET, which would benefit water resources management for film mulched croplands with shallow groundwater. [ABSTRACT FROM AUTHOR]

As part of China's first Mars exploration mission 'Tianwen-1', the Zhurong rover has successfully touched down on the surface of southern Utopia Planitia on May 15th 2021 and has been conducting surface operations for several months. A multispectral camera (MSCam), as an important payload onboard the Zhurong rover, aims to acquire multispectral images to investigate the morphological characteristics and mineralogic properties of the Martian surface. In this study, a detailed optimization design for the MSCam was carried out to achieve the abovementioned scientific objectives. The MSCam can perform multispectral imaging without chromatic aberration by utilizing eight narrow bandwidth filters made of glass of different thicknesses. Clear images of observation targets at different distances can be obtained by utilizing the six focal plane compensation lenses of varying thicknesses through the rotation of wheels. Calibration experiments, key specification tests and ground verification tests were also conducted in this study. Our results show that the pixel resolution of the MSCam can reach 0.146 mrad, the system static modulation transfer function (MTF) of the MSCam is better than 0.25@525 nm, and the signal-to-noise ratio (SNR) is higher than 40 dB, all of which allow clear imaging and accurate multispectral data acquisition of the targets. The high-resolution images obtained by the MSCam will provide detailed geological context for the data interpretation of other payloads on the rover, such as the Mars surface composition detector (MarSCoDe). The mineralogy information of the targets (e.g., fresh rock, dune) indicated by the MSCam multispectral data will also help to constrain the surface material composition of Mars. [ABSTRACT FROM AUTHOR]

• A 3D nanoporous holey graphene with both N and Mo dopants is prepared. • The edge-rich holey graphene facilitates the doping of pyridinic N and single-atom Mo. • The co-doped nanoporous holey graphene is highly active for ORR and OER. Materials co-design of the single-atom catalytic centers and the supports can push the limits of the emerging wearable metal-air batteries. The metal single-atom catalysts are required to be bifunctional with high efficient electrocatalytic activities for both oxygen reduction and evolution reactions (ORR and OER), and preferably non-noble. The supports, on the other hand, in addition to the requirements of being free-standing, flexible and porous, are required to strongly interact with the metal species to prevent their aggregation. However, satisfying these requirements simultaneously is yet challenging. Here, a free-standing 3D nanoporous holey graphene with both N and single-atom Mo dopants is prepared. The nanoholes are created by chemical vapor deposition method on nanoporous NiMo alloy templates with their surface decorated with catalytically inert SiO 2 nanoparticles. The edge-rich graphene induced by the nanoholes facilitates the doping of pyridinic N and single-atom Mo in the fringe near the edges. The resulting N and Mo co-doped nanoporous holey graphene exhibits high bifunctional ORR and OER catalytic activities in alkaline electrolytes. The synergetic effects between N and Mo dopants are also revealed by density functional theory calculations. When incorporated in a solid-state zinc-air battery, the battery is bendable and can be continuously discharged/charged for 88 h with a high power density of 83 mW cm−2. This work provides an efficient route to design metal single atom/cluster doped 3D freestanding nanoporous graphene as flexible electrodes. [ABSTRACT FROM AUTHOR]

Laboratory experiments were performed to investigate the effect of mud slurry on the flow resistance of cohesionless particles in debris flow. For one thing, natural angles of repose were measured for the gravel materials resting in air, in water, and in mud slurry separately. For another, rheological tests were taken using a vane rheometer to measure the torque-time response of sand particles within mud slurries of varying solid concentrations both at low and high rotational speeds. The stable torque obtained at the low rotational rate, which represents flow resistance primarily caused by particle contact friction, was nondimensionalized to compare the internal friction coefficient in each case. Furthermore, flow resistance of sand particles within one of the mud slurries was measured over a wide range of rotational speeds to compare with that in the dry system. It was found that the mud slurry has no significant effects on the frictional coefficient of cohesionless coarse particles. However, the mud slurry tends to decrease flow resistance of the particles, with the effect being more significant at higher rotational speeds or for more concentrated slurries. This derives from excess pore fluid pressure, which is easier to maintain at higher shear rates or within more cohesive slurries. [ABSTRACT FROM AUTHOR]

The city-water system relationship (CWSR) plays a key role in a region's sustainable development. Unprecedented urbanization and growing populations impose great pressures on water resources under global climate change. To date, few insights have been reported for regional CWSRs at a long-term scale and high spatial resolution. Here, we investigate the evolution of cities from primitive society and the influences of the water system and environmental heterogeneity in the northern part of the North China Plain. We find that an artificial water system replaced the natural water system and gradually dominated city development, as evidenced by the construction of the Grand Canal. Megacities such as Beijing and Tianjin have implemented water conservation projects that draw on resources outside the watershed to sustain regional development. Our study supports local practices to restore water circulation in a watershed to enhance the region's resilience and emphasizes the environmental influences on cities. • This study investigated the city-water system relationship (CWSR) in the North China Plain over two millennia. • Six interactive processes are induced between the city development and the water system changes. • The human water system replaced the natural water system marked as the Grand Canal Construction in this region. • Engineering-based CWSR is less resilient than nature-based one, thus local actions are essential. [ABSTRACT FROM AUTHOR]