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In this work, a highly stretchable and sensitive strain sensor using silver nanowires (Ag NWs)/multi-walled carbon nanotubes (MWCNTs) on hair band is proposed. The fabrication process of such sensors enabled scalable and facile production with low cost by dipping hair band into Ag NWs/MWCNTs composites suspension. The sensing performance of the sensors was optimized by tuning the Ag NWs/MWCNTs mass ratio. The hair band based strain sensor with Ag NWs/MWCNTs mass ratio of 30 exhibited the best performance with high sensitivity of 416.0 and good stretchability up to 70%. Moreover, great repeatability and long-term stability could be achieved over 7500 cycles of stretch-release. This Ag NWs/MWCNTs-hair band sensor can be used for monitoring human motions and swallowing action.

Although two-dimensional fused-ring electron acceptors (FREAs) have recently attracted increasing attention, designing highly efficient two-dimensional FREAs with a new heterocycle-based two-dimensional central core for further development is still a great challenge. Herein, two chlorinated two-dimensional fused-ring electron acceptors (namely C8T-BDT4Cl and C8T-BDSe4Cl) were synthesized for polymer solar cells, featuring with the two-dimensional conjugated central donor units by alkylthienyl-substituted benzo[1,2-b:4,5-b′]dithiophene (BDT) and benzo[1,2-b:4,5-b′]diselenophene (BDSe), respectively. Compared with C8T-BDT4Cl, C8T-BDSe4Cl exhibits a red-shifted absorption spectrum and a narrower optical bandgap. Moreover, we first studied the single crystals of such two-dimensional conjugated FREAs and the crystallographic analysis indicates that both acceptors presented 3D network packing with three independent molecular conformations, but C8T-BDSe4Cl exhibits more enhanced multiple intermolecular interactions with slightly shorter π–π interaction distances. A C8T-BDSe4Cl:PM6-based blend film exhibited a more favorable morphology with better face-on intermolecular packing with a longer coherent length and more suitable phase separation, resulting in more efficient charge separation, transport, and collection. Consequently, benefiting from the above-mentioned merits, polymer solar cells (PSCs) based on C8T-BDSe4Cl:PM6 presented a much higher power conversion efficiency (PCE) of 13.5% with higher Jsc than that of sulfur-containing analogue-based C8T-BDT4Cl:PM6 (12.2%). These results indicate a unique application prospect of the selenium-substituted FREAs and demonstrate that combination of the two-dimensional conjugated central core and selenium-substituted in the central electron-rich position strategy is an effective approach to improve the Jsc value and PCE of two-dimensional FREA-based PSCs.

Oxidation and hot corrosion behaviors at 900 °C of Nb−Si based ultrahigh temperature alloys were investigated. Both oxidation and hot corrosion kinetics curves of the alloy involve an initial parabolic stage and a later rapid linear stage. In the initial oxidation stage (1−50 h), a thin and continuous scale is formed on the alloy surface, while severe pest degradation phenomenon is observed in the linear oxidation stage. Compared with oxidation of the alloy in static air, a linear hot corrosion stage happens earlier and catastrophic scale disintegration occurs after hot corrosion for 20−100 h, demonstrating that molten salts (Na2SO4 and NaCl) could significantly accelerate the oxidation process of the alloy. STEM results indicate that the corroded scale consists mainly of TiO2, Nb2O5, TiNb2O7, amorphous silicate and NaNbO3.

This study proposed a GAN-based reconstruction method-cascaded data consistency generative adversarial network (CDCGAN) to recover high-quality PET images from filtered back projection PET images with streaking artifacts and high noise. First, the authors embed defined data consistency layer (DC layer) in their generator network to constrain the reconstruction process and adjust accurately generated faked PET images. Second, to improve the accuracy of reconstruction on average, their generator network was built iteratively to achieve better performance with simple structures. They observed that the proposed CDCGAN allows the preservation of fine anomalous features while eliminating the streaking artifacts and noise. Experimental results show that the reconstructed PET images by their methods perform well comparably to other state-of-the-art methods but at a faster speed. A clinical experiment was also performed to show the validity of the CDCGAN for artifacts reduction.

Positron emission tomography (PET) image reconstruction from low-count projection data and physical effects is challenging because the inverse problem is ill-posed and the resultant image is usually noisy. Recently, generative adversarial networks (GANs) have also shown their superior performance in many computer vision tasks and attracted growing interests in medical imaging. In this work, the authors proposed a novel model [deep residual generative adversarial network (DRGAN)] based on GANs for the reduction of streaking artefacts and the improvement of PET image quality. An innovative feature of the proposed method is that the authors trained a generator to produce `residual PET map' (RPM) for image representation, rather than generate PET images directly. DRGAN used two discriminators (critics) to enforce anatomically realistic PET images and RPM. To better boost the contextual information, the authors designed residual dense connections followed with pixel shuffle operations (RDPS blocks) that encourage feature reuse and prevent losing resolution. Both simulation data and real clinical PET data are used to evaluate the proposed method. Compared with other state-of-the-art methods, the quantification results show that DRGAN can achieve better performance in bias-variance trade-off and provide comparable image quality. Their results were rigorously evaluated by one radiologist at the Shanxi Cancer Hospital.

The accurate identification of KRAS mutation status on medical images is critical for doctors to specify treatment options for patients with rectal cancer. Deep learning methods have recently been successfully introduced to medical diagnosis and treatment problems, although substantial challenges remain in the computer-aided diagnosis (CAD) due to the lack of large training datasets. In this paper, we propose a multi-branch cross attention model (MBCAM) to separate KRAS mutation cases from wild type cases using limited T2-weighted MRI data. Our model is built on multiple different branches generated based on our existing MRI data, which can take full advantage of the information contained in small data sets. The cross attention block (CA block) is proposed to fuse formerly independent branches to ensure that the model can learn as many common features as possible for preventing the overfitting of the model due to the limited dataset. The inter-branch loss is proposed to constrain the learning range of the model, confirming that the model can learn more general features from multi-branch data. We tested our method on the collected dataset and compared it to four previous works and five popular deep learning models using transfer learning. Our result shows that the MBCAM achieved an accuracy of 88.92% for the prediction of KRAS mutations with an AUC of 95.75%. These results are a significant improvement over those existing methods (p < 0.05).

To solve the poor cyclability of faradic supercapacitors (SCs), the authors reported a unique porous carbon (PC) coating with “gap shell” structure on carbon fiber cloth (CFC)/NiS2 materials. This gap shell PC coating was fabricated by combining atomic layer deposition (ALD) Al2O3 and molecular layer deposition alucone, followed by carbonization and etching. The as-prepared CFC/NiS2/PC composites were directly used as binder-free electrodes for SCs. Benefited from its novel nanostructure, the CFC/NiS2/PC electrode shows a large specific capacitance of 1034.6 F/g at 1 A/g and considerable rate capability of 67% capacitance, retaining ratio within 1–20 A/g. The cyclability of the CFC/NiS2/PC electrode is enhanced by 50% relative to the mere CFC/NiS2 after 2000 cycles, which is attributed to the gap and electrically conductive PC coating. Hence, this work provides a promising approach to design gap shell layer for improved cyclability of faradic SCs and other practical applications in energy storage electronics.

Among the various types of lung nodules, ground glass nodules (GGNs) are difficult to segment accurately due to complex morphological characteristics. Moreover, GGNs are associated with a higher malignancy probability. Three-dimensional (3D) segmentation and reconstruction techniques can help physicians intuitively elucidate the relationship between lung nodules and their surrounding tissues. We propose an improved supervoxel 3D region growing approach based on positron emission tomography/computed tomography (PET/CT) multimodal data for the segmentation and reconstruction of GGNs. First, the seed point is automatically located with PET information and a 3D mask is generated. Then, a fuzzy connectivity (FC) map is generated based on the 3D mask, and an improved supervoxel 3D region growing is utilized on a fuzzy connectivity map under the constraints of the 3D mask. Finally, 3D GGNs segmentation and reconstruction results are obtained. Qualitative and quantitative comparisons between our proposed method and other region growing methods shows great superiority of our proposed method, with the Jaccard similarity coefficient between our proposed method and physician manual segmentation reaching 95.61%; the average processing time is 16.38 s. Experimental results show that our proposed supervoxel-based 3D region growing method is very promising for assisting physicians in diagnosis.

Uniform C-Al2O3 composite coating with homogeneous thickness was adopted to improve the electrochemical properties of LiNi0.6Co0.2Mn0.2O2 by the pyrolysis of molecular layer deposited alucone in argon. Compared with LiNi0.6Co0.2Mn0.2O2 coated atomic layer deposited Al2O3, C-Al2O3 coated electrode delivered high discharge capacity, good rate capability and durable cyclic stability, even at elevated temperature. Such enhanced electrochemical performance could be attributed to the synergistic effect between the amorphous Al2O3 and conductive carbon in the dual-functional C-Al2O3 composite coating, resulting in the improved structural stability and electrochemical kinetics of LiNi0.6Co0.2Mn0.2O2 cathode. The network of carbon in C-Al2O3 composite coating supplied high electrical conductivity, and lowers the charge transfer resistance on the surface of electrode. Meanwhile, the uniform amorphous Al2O3 with its flexible structure improved the structural stability of cathode and favored the diffusion of Li+ ions.

Thermal cycling tests (TCT) have been widely used for performance demonstration and reliability validation of the spacecraft electronics. The integrated tailoring model can provide customized testing conditions of TCT for different spacecraft electronics, which is different with the traditional unified tailoring model in MIL-STD-1540. Considering the influence of welding material, defect degrees and test levels, experimental verification had been done on solder samples. The evaluation indicators including test cost, simulation bias and simulation accuracy have been defined and compared between two different tailoring methods. The results show that for Sn/Pb solder samples, the testing effects of the two tailoring methods are the same. But for other materials solder samples, the integrated method can be used to achieve better environmental stress screening with lower cost than the traditional method. Such as the SAC solder, the simulation accuracy is increased by 0–10%, and the testing cost is decreased by 0–7%.

The historical failure data of launched spacecraft are very useful to improve the designing and manufacturing of spacecraft, optimize ground tests and reduce the flight risks of spacecraft. In 2010, the study of spacecraft failure data was initiated in China. Since 2017, 2593 on-orbit failure data and 1298 ground failure data for 120 spacecraft launched from 2000 to 2017 have been identified and collected, including navigation satellites, communication satellites, remote sensing satellites, deep space exploration missions and manned spacecraft. In this paper, the development of China's aerospace manufacturing industry in the last decade is objectively evaluated by analysis of these failures, based on the most comprehensive available statistics of Chinese spacecraft. Detailed failure causes, failure impacts, affected subsystems, higher-risk components of spacecraft are analyzed. The failures exposure rate of ground tests and the number of early flight failures are also numerically estimated. Finally, the statistical evidence is provided in this paper to support the conclusion: reducing design errors, improving advanced research, adequate redundancy, effective space environmental protection measures, and adequate ground testing are the key to improve spacecraft quality.

In this work, Ni3S2/Ni foam was successfully synthesized using a facile gas-phase method of annealing Ni foam in H2S atmosphere. It was used as a binder free electrode for high-performance supercapacitors. The areal capacitance increases rapidly in the initial charge-discharge cycling and then reaches a stable stage. An ultrahigh areal capacitance of 9.88 F cm−2 at the current density of 10 mA cm−2 is achieved in the stable charge-discharge stage, which is around 88 times of initial capacitance (112.5 mF cm−2). Further studies reveal that surface Ni3S2 transforms into porous Ni(OH)2 during charge-discharge process, and surface area increases more than 100 times. The soaring specific surface area is the dominant factor contributing to the increased areal capacitance. More importantly, this self-formed porous structure exhibits ultra-stable long-time cycling ability, as no capacity fading is observed even after 60000 cycles of charge-discharge at high current density (150 mA cm−2). These results indicate that self-formed porous Ni(OH)2 structure during electrochemical cycling maybe a promising electrode for high performance supercapacitor applications.

In this work, we propose a new design of flexible strain sensors based on biomimetic patterned-polydimethylsiloxane (P-PDMS) and multi-walled carbon nanotubes (MWCNTs) decorated with Ir nanoparticles (NPs) deposited by atomic layer deposition (ALD). The biomimetic flexible strain sensors of Ir NPs@MWCNTs on patterned PDMS show superior sensitivity (34.96), larger sensing range (0–30%), better stability (＞10,000 stretch and release cycles), and fairly faster response time (150 ms) under optimal 200 ALD Ir cycles. This is attributed to the synergic effect of utilizing patterned PDMS films copied from duck webs as substrates and Ir@CNTs as sensing materials. Furthermore, the flexible strain sensors can detect not only stretch but also bend stress rapidly and accurately. Above all, a simple, green, and low cost method has been developed to fabricate the flexible biomimetic strain sensors with patterned PDMS and Ir NPs@MWCNTs, exhibit promising prospects in human motion detection, wearable electronics, human-machine interfaces, etc.

Ti-based maleic acid (MA) hybrid films were successfully fabricated by molecular layer deposition (MLD) using organic precursor MA and inorganic precursor TiCl4. The effect of deposition temperature on the growth rate, composition, and bonding mode of hybrid thin films has been investigated systematically. With increasing temperature from 140 to 280 °C, the growth rate decreases from 1.42 to 0.16 A per MLD cycle with basically unchanged composition ratio of C:O:Ti in the films. Fourier transform infrared spectra indicate that all hybrid films show preference for bidentate bonding mode. Further analyses of X-ray photoelectron spectroscopy and in situ quartz crystal microbalance elucidate that as-deposited MLD Ti-MA hybrid films consist of inorganic Ti-O-Ti units and organic-inorganic Ti-MA units. In addition, the density functional theory calculation was performed to investigate the possible reaction mechanism of the TiCl4-MA MLD process, which is well consistent with experimental results. More importantly, upon comparison with the TiCl4-fumaric acid MLD system, it is demonstrated that the cis- and trans-configurations of butenedioic acid influence the MLD growth, bonding mode, stability, and charging ability of MLD hybrid films. Ti-MA hybrid films exhibit better stability and charging ability than Ti-FA hybrid films, benefiting from the inorganic Ti-O-Ti units in the hybrid films.

A charge trapping memory device using Ta2O5/Al2O3/TiO2/Al2O3/Ta2O5 (TATiAT) nanocomposite high-k dielectrics as charge trapping layer (CTL) and amorphous Al2O3 as the tunneling and blocking layers has been investigated, in which all the high-k dielectric films were fabricated by atomic layer deposition (ALD) technique. A large memory window of 10.0 V with higher charge trap density of 1.10 × 1013 cm−2 at gate voltage of ±10 V has been achieved. The better storage characteristic is attributed to the inter-diffusion between nanocomposite high-k oxides and the formation of more oxygen vacancies in CTL. The device shows the fast P/E speed and excellent endurance characteristics. A 70% initial memory window can be maintained after 10 years of retention by using the extrapolation method. The large conduction band offsets of 1.02 eV between TATiAT and Al2O3 is beneficial to retention characteristic due to the deep trap level.

Feature extraction of lung nodules is very important in the diagnosis of lung cancer and is the premise of feature description, target matching, recognition and benign and malignant diagnosis. The main contribution of this work is the development of a new end-to-end feature extraction method that learns effective feature representation from images to effectively establish the direct relationship between multiple features and tissue features (that is, benign or malignant). The architecture consists of three seamlessly connected functional layers. RGB multichannel can automatically extract ROI sequence images involving lung parenchyma from the lung imaging sequence. The feature extraction layers, using Principal Component Analysis Network - random binary hash (PCANet-RBH), a) extract high-level semantic features of the R/G/B channel by cascading PCA and fuse the extracted normal color patterns, and b) generate multiple binary patterns via RBH to produce richer features with color information. The connected spatial pyramid pooling (SPP) layer can extract the location features of the lung nodules and map the feature matrix to the low-dimensional space and then establish a correspondence between the image features and the organizational identity. We validate the performance of the proposed method using the public dataset LIDC. The experimental results show that the fusion features extracted by our method have high and stable classification accuracy (accuracy:93.25 ± 0.53, sensitivity:93.12 ± 0.62 specificity:91.37 ± 0.62), which is significantly better than the traditional algorithm for lung nodule feature extraction. Moreover, RGB-PCANet has a short training time, which can meet the requirements of real-time diagnosis of lung cancer. In general, the advantage of our framework is that it provides a better and more comprehensive method to establish a direct relationship between image high-level semantic features, color features, location features and tissue features, making it an attractive clinical diagnostic tool for lung cancer.

A two-dimensional (2D) halogenated thiophene side chain strategy was proposed and two new 2D halogenated electron-rich fused central core units, FBDT and ClBDT, based on linear benzo[1,2-b:4,5-b′]di(cyclopenta[2,1-b:3,4-b′]dithiophene) with fluorinated and chlorinated thiophene side chains have been developed for the first time, respectively. Then, a family of multihalogenated A–D–A structured non-fullerene small molecule acceptors (NF-SMAs), namely HBDT-4Cl, FBDT-4Cl and ClBDT-4Cl, based on the same dichlorinated 1,1-dicyanomethylene-3-indanone (IC) as the terminal group and three different electron-rich central donor cores (a simple thiophene side chain functionalized central donor core HBDT, its fluorinated analogue FBDT, and its chlorinated analogue ClBDT), respectively, were synthesized for high performance organic solar cells. Compared to nonhalogenated analogues, HBDT-4Cl, FBDT-4Cl and ClBDT-4Cl exhibit slightly wider bandgaps and enhanced molar absorption coefficients, slightly down-shifted energy levels, and obviously improved crystallinity in neat thin films. After blending with the polymer donor PBDB-T-2F, the as-cast FBDT-4Cl/PBDB-T-2F blend films show the highest and most balanced hole/electron mobilities, the highest charge dissociation and collection efficiency, and the most proper phase separation feature among these blend films. Thus, the as-cast FBDT-4Cl/PBDB-T-2F based device exhibits the best power conversion efficiency (PCE) of 12.36%, which is higher than that of ClBDT-4Cl (11.65%) and HBDT-4Cl (10.35%) based devices owing to the higher Jsc and FF. The PCE of 12.36% is the highest value for fluorinated central core functionalized NF-SMA-based binary organic solar cells. Our results revealed that introduction of halogenated thiophene side chains, especially fluorinated thiophene side chains, in an electron-rich fused central core is an effective strategy to achieve high-performance two-dimensional aromatic side-chain functionalized NF-SMAs.

In the semiconductors and related industries, the fabrication of nanostructures and nanopatterns has become progressive demand for achieving near-atomic accuracy and selectivity in etching different materials, particularly in ultra-thin gate dielectrics and ultra-thin channels used in field-effect transistors and other nanodevices below 10 nm scale. Atomic layer etching (ALE) is a novel technique for removing thin layers of material using sequential and self-limiting reactions. Different from most ALE processes using plasma-enhanced or other energetic particles-enhanced surface reactions, thermal ALE realizes isotropic atomic-level etch control based on sequential thermal-drive reaction steps that are self-terminating and self-saturating. Thermal ALE can be viewed as the reverse of atomic layer deposition (ALD), both of which define the atomic layer removal and growth steps required for advanced semiconductor fabrication. In this review, we focus on the concept and basic characteristics of the thermal ALE in comparison with ALD. Several typical thermal ALE mechanisms including fluorination and ligand-exchange, conversion-etch, oxidation and fluorination reactions are intensively introduced. The pros and cons of thermal ALE, plasma ALE, and traditional plasma etching are compared. Some representative materials and their typical thermal ALE processes are summarized. Finally, the outlook and challenges of thermal ALE are addressed. Keywords: Thermal atomic layer etching, Atomic layer deposition, Self-limiting, Reaction mechanism, Atomic-scale precision

The introduction of metal nanocrystals (NCs) has been confirmed to improve electrical uniformity of oxide-based resistive random access memory (RRAM) devices significantly; however, the current reports do not systematically elucidate the relationship between the size/distribution of NCs and the electrical uniformity of RRAM devices. In this paper, we focused on the impact of metal NCs size and areal density on the resistive switching (RS) performances of oxide RRAM by atomic layer deposition (ALD) based on the experimental results and theoretical calculation. The dependence of ALD cycles of 50–130 during Pt or CoPt x NCs growth on the RS parameters of Al2O3 or HfO2 memory units has been evaluated systematically. The RRAM embedded Pt or CoPt x NCs shows the trends: with increasing ALD cycles, the forming voltage, set/reset voltage, the resistance in off and on state, and ${R}_{ \mathrm{\scriptscriptstyle OFF}}/{R}_{ \mathrm{\scriptscriptstyle ON}}$ ratio entirely first decrease, then flatten, and increase later with a minimum value at about 100 cycles. Although all metal NCs with various sizes enhance the electric field strength compared to at the planar region, only metal NCs with proper NCs size and areal density (9 nm/6– $10\times 10^{\textsf {11}}$ /cm2 in this paper) can effectively produce stronger localized electric field at the tip of metal NCs, leading to optimal RS behavior.

In February 2020, Beijing, China andCalifornia, USA respectively released road test reports of 2019 for autonomous vehicles. Beijing and California respectively represent the highest level of testing and application of autonomous vehicles in the two countries. This article will compare the test items, evaluation criteria and technical defects of each autonomous vehicle company in the road test reports of China and the United States, also analyze the existing problems, and propose an idea for the construction of a comprehensive test site for autonomous vehicles. This article aims to solve the prominently exposed problems in decision-making and planning in autonomous vehicles with DQN algorithm-base vehicle fleet, and to look forward to the future development trend of autonomous driving testing.

The global land area devoted to rubber plantations has now reached 13 million hectares, and the further expansion of these rubber plantations at the expense of tropical forests will have significant adverse effects on the ecological environment. Rubber-based agroforestry systems are considered a preferable approach for ameliorating the ecological environment. Many researchers have focused on the positive effects of rubber-based agroforestry systems on the ecological environment, while ignoring the risks involved in the establishment of rubber-based agroforestry systems. The present study investigated the effects of different-aged rubber-based agroforestry systems on the abundance and diversity of ground arthropods. It has been observed that the abundance and taxon richness of ground arthropods generally showed no difference when comparing young and mature rubber plantations. The rubber-based agroforestry systems significantly decreased the understory vegetation species, along with the abundance and taxon richness of ground arthropods compared to the same aged-rubber monoculture plantations. In addition, the change in the abundance and taxon richness of ground arthropods was greatly affected by the understory vegetation species and soil temperature. The abundance and taxon richness of ground arthropods decreased with the decrease in number of species of understory vegetation. The study results indicate that the establishment of rubber-based agroforestry systems have adversely affected the abundance and richness of ground arthropods to an extant greater than expected. Therefore, single, large rubber-based agroforestry systems are not recommended, and the intercropping of rubber and rubber-based agroforestry systems must be designed to promote the migration of ground arthropods between different systems.

Learning network embeddings has attracted growing attention in recent years. However, most of the existing methods focus on homogeneous networks, which cannot capture the important type information in heterogeneous networks. To address this problem, in this paper, we propose TransN, a novel multi-view network embedding framework for heterogeneous networks. Compared with the existing methods, TransN is an unsupervised framework which does not require node labels or user-specified meta-paths as inputs. In addition, TransN is capable of handling more general types of heterogeneous networks than the previous works. Specifically, in our framework TransN, we propose a novel algorithm to capture the proximity information inside each single view. Moreover, to transfer the learned information across views, we propose an algorithm to translate the node embeddings between different views based on the dual-learning mechanism, which can both capture the complex relations between node embeddings in different views, and preserve the proximity information inside each view during the translation. We conduct extensive experiments on real-world heterogeneous networks, whose results demonstrate that the node embeddings generated by TransN outperform those of competitors in various network mining tasks.

In order to investigate the transient hydrodynamic characteristics of water-jet propulsion with a screw mixed pump during the startup period and to overcome the difficulties in measuring the transient process parameters over a very short period of time, a method based on a flume experiment combined with computational fluid dynamics (CFD) is proposed. The thrust and torque of the pump-jet propulsion according to mooring status at different rotational speeds were measured by the test, which provided a group of data for the boundary and initial conditions of the numerical calculation of the user-defined function (UDF). Consecutive changes in the parameters of the water-jet propulsion dynamics can be captured from the numerical simulation of the startup process with the UDF. Thus, the transient hydrodynamic characteristics of water-jet propulsion according to time or rotation speed were obtained. The results show that the relationship between the thrust or torque of the water-jet propeller and pump rotational speed is close to the quadratic functions. The energy characteristic parameters of screw mixed water-jet pump, such as the flow rate, head, shaft power, and efficiency, rapidly increase and decrease and then remain relatively stable.

In this work, TiN film deposited by plasma enhanced atomic layer deposition (PEALD) is adopted to modify the commercial anatase TiO2 powders. A series of analyses indicate that the surface modification of 20, 50 and 100 cycles of TiN by PEALD does not change the morphology, crystal size, lattice parameters, and surface area of TiO2 nano powders, but forms an ultrathin amorphous layer of nitrogen doped TiO2 (TiOxNy) on the powder surfaces. This ultrathin TiOxNy can facilitate the absorption of TiO2 in visible light spectrum. As a result, TiOxNy coated TiO2 powders exhibit excellent photocatalytic degradation towards methyl orange under the visible light with good photocatalytic stability compared to pristine TiO2 powders. TiOxNy (100 cycles PEALD TiN) coated TiO2 powders exhibit the excellent photocatalytic activity with the degradation efficiency of 96.5% in 2 hours, much higher than that of pristine TiO2 powder of only 4.4%. These results clearly demonstrate that only an ultrathin surface modification layer can dramatically improve the visible light photocatalytic activity of commercial TiO2 powders. Therefore, this surface modification using ALD is an extremely promising route to prepare visible light active photocatalysts.

Transparent conducting oxide of Al-doped ZnO (AZO) films were prepared by atomic layer deposition (ALD) using diethylzinc (DEZ) and 3 kinds of Al precursors, including trimethylaluminum (TMA), aluminum isopropoxide (AIP) and AlCl 3 . The impact of ZnO/Al 2 O 3 cycle ratios from 9:1 to 39:1 and Al precursors on the growth rate, Al dopant concentration, structure, and resistivity of AZO films were investigated deeply. At the same ZnO/Al 2 O 3 cycle ratio, the film thickness decreases and the Al dopant concentration increases gradually with TMA, AIP and AlCl 3 precursors in turn. Generally, the Al doping leads to poorer crystallinity and better conductivity for AZO films. Both TMA-AZO and AIP-AZO films with 19:1 ZnO/Al 2 O 3 cycle ratio show the lowest resistivity of 3.3–4 × 10 − 3 Ω cm with Al doping content of 2.1% and 2.3%, respectively, which can be well explained by the effective field model. Additionally, all the AZO films exhibit great optical transparency of > 85% for wavelengths of 370–900 nm.

The synthesis of three neutral bis-cyclometalated iridium(III) complexes [Ir(pba)2(S^S)] (pbaH=4-(2-pyridyl)benzaldehyde; S^S=Et2NCS2 − (1), iPrOCS2 − (2), (nPrO)2PS2 − (3)) from [{Ir(μ-Cl)(pba)2}2] and the corresponding sodium or potassium dithiolates in methanol-dichloromethane is described. The composition of complexes 1–3 is discussed on the basis of 1H NMR, 13C NMR, IR, and mass spectroscopy, and the crystal structures of 1 and 3 were determined by X-ray crystallography. The absorption and emission spectra show that the [Ir(pba)2(S^S)] complexes may be effective candidates as green-emitting phosphorescent materials. The stability of the three cyclometalated iridium(III) complexes towards different transition metal ions was also investigated in acetonitrile-water solvent.

This study describes the synthesis of aluminum sulfide (AlSx) thin films by atomic layer deposition (ALD) using tris(dimethylamido)aluminum and hydrogen sulfide. We employed a suite of in situ measurement techniques to explore the ALD AlSx growth mechanism, including quartz crystal microbalance, quadrupole mass spectrometry, and Fourier transform infrared spectroscopy. A variety of ex situ characterization techniques were used to determine the growth characteristics, morphology, elemental composition, and crystallinity of the resultant AlSx films. This study revealed that the AlSx growth was self-limiting in the temperature range 100–250 °C, and the growth per cycle decreased linearly with increasing temperature from ∼0.45 A/cycle at 100 °C to ∼0.1 A/cycle at 250 °C. The AlSx films were amorphous in this temperature range. We conducted electrochemical testing to evaluate the ALD AlSx as a potential anode material for lithium-ion batteries (LIBs). The ALD AlSx exhibited reliable cyclability over 60 dischar...

The facial tris-cyclometalated iridium(III) complex fac-Ir(dmpopopz)3 (dmpopopzH = 1-(2,6-dimethylphenyloxy)-4-(4-phenyloxyphenyl)-phthalazine) was synthesized from the reaction of iridium(III) chloride hydrate and ligand dmpopopzH in refluxing ethoxyethanol. The conformation of complex fac-Ir(dmpopopz)3 is described on the basis of the 1H NMR, 13C NMR, FT-IR and mass spectroscopies, the crystal structure of fac-Ir(dmpopopz)3 was determined by X-ray crystallography, and the theoretical calculation of complex fac-Ir(dmpopopz)3 was also investigated by the DFT method. The absorption and emission spectral results exhibit that complex fac-[Ir(dmpopopz)3] may be used as a red-emitting phosphorescent material. Efficient OLEDs have been achieved using the complex fac-[Ir(dmpopopz)3] in the red-emitting region.

Coating a protection layer on the surface of Li- and Mn-rich oxide cathode is an effective approach to improve its cycling stability. In this paper, a conductive copolymer P(VDF-TrFE) coating on the surface of Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (LMNCO) was synthesized via wet-chemical method. The P(VDF-TrFE) coating layer with uniform thickness around 5 nm is confirmed by X-ray diffraction, scanning electronic microscopy, high-resolution transmission electron microscopy, infrared and X-ray photoelectron spectroscopy. Results reveal that β -phase P(VDF-TrFE) coated LMNCO electrode exhibits remarkably improved Coulombic efficiency, cycleability and rate capability, even at elevated temperature. Such improved electrochemical performance is attributed to the fact that the uniform and continuous P(VDF-TrFE) coating can not only suppress the undesirable side reactions between the electrode and electrolyte, but also enhance the structural stability of LMNCO cathode. Most importantly, the conductive P(VDF-TrFE) layer is in favour of Li + diffusion and electron transport of the coated cathode.

A series of Y zeolites exchanged with different amount of cerium and lanthanum cations were investigated. Comprehensive routine analysis tools including X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), X-ray diffraction (XRD) and Py-Fourier transform infrared spectroscopy (Py-FTIR) were used to identify the cation location, and the result was verified via XRD Rietveld study. The results revealed that almost all the RE cations in RE-4, most cations in RE-8 to RE-14 and part of cations in RE-16 were located in the sodalite cage. The AlIV/(AlV+AlVI) values revealed by 27Al MAS NMR spectra, the silicon aluminum ratio of the framework (SARF) values deduced from 29Si MAS NMR spectra and XRD, and hydroxyl amount were reasonably in accordance with the location and content of rare earth cations. The hydrothermal stability derived from in situ XRD investigation and catalyst activity provided by micro-activity test manifested that samples RE-8 to RE-14 exhibited better performances than RE-4 and RE-16, among which RE-12 had the best properties. The phenomena were interpreted by the cation location and structural properties.

The HfO2/TiO2/HfO2 trilayer-structure resistive random access memory (RRAM) devices have been fabricated on Pt- and TiN-coated Si substrates with Pt top electrodes by atomic layer deposition (ALD). The effect of the bottom electrodes of Pt and TiN on the resistive switching properties of trilayer-structure units has been investigated. Both Pt/HfO2/TiO2/HfO2/Pt and Pt/HfO2/TiO2/HfO2/TiN exhibit typical bipolar resistive switching behavior. The dominant conduction mechanisms in low and high resistance states (LRS and HRS) of both memory cells are Ohmic behavior and space-charge-limited current, respectively. It is found that the bottom electrodes of Pt and TiN have great influence on the electroforming polarity preference, ratio of high and low resistance, and dispersion of the operating voltages of trilayer-structure memory cells. Compared to using symmetric Pt top/bottom electrodes, the RRAM cells using asymmetric Pt top/TiN bottom electrodes show smaller negative forming voltage of −3.7 V, relatively narrow distribution of the set/reset voltages and lower ratio of high and low resistances of 102. The electrode-dependent electroforming polarity can be interpreted by considering electrodes’ chemical activity with oxygen, the related reactions at anode, and the nonuniform distribution of oxygen vacancy concentration in trilayer-structure of HfO2/TiO2/HfO2 on Pt- and TiN-coated Si. Moreover, for Pt/HfO2/TiO2/HfO2/TiN devices, the TiN electrode as oxygen reservoir plays an important role in reducing forming voltage and improving uniformity of resistive switching parameters.

In situ-formed SiO2 was introduced into HfO2 gate dielectrics on Ge substrate as interlayer by plasma-enhanced atomic layer deposition (PEALD). The interfacial, electrical, and band alignment characteristics of the HfO2/SiO2 high-k gate dielectric stacks on Ge have been well investigated. It has been demonstrated that Si-O-Ge interlayer is formed on Ge surface during the in situ PEALD SiO2 deposition process. This interlayer shows fantastic thermal stability during annealing without obvious Hf-silicates formation. In addition, it can also suppress the GeO2 degradation. The electrical measurements show that capacitance equivalent thickness of 1.53 nm and a leakage current density of 2.1 × 10−3 A/cm2 at gate bias of Vfb + 1 V was obtained for the annealed sample. The conduction (valence) band offsets at the HfO2/SiO2/Ge interface with and without PDA are found to be 2.24 (2.69) and 2.48 (2.45) eV, respectively. These results indicate that in situ PEALD SiO2 may be a promising interfacial control layer for the realization of high-quality Ge-based transistor devices. Moreover, it can be demonstrated that PEALD is a much more powerful technology for ultrathin interfacial control layer deposition than MOCVD.

Sulfur is easy to be incorporated into ZnO nanoparticles by the solution-combustion method. Herein, the magnetic and adsorption properties of a series of ZnO1−xSx (x = 0, 0.05, 0.1, 0.15, and 0.2) nanoparticles were systematically investigated. The X-ray diffraction patterns show that the as-prepared ZnO1−xSx nanoparticles have the hexagonal wurtzite structure of ZnO with a low sulfur content that gradually transforms into the zinc blende structure of ZnS when the x value is greater than 0.1. PL spectra show several bands due to different transitions, which have been explained by the recombination of free excitons or defect-induced transitions. The introduction of sulfur not only modifies the bandgap of ZnO, but also impacts the concentration of Zn vacancies. The as-prepared ZnO shows weak room-temperature ferromagnetism, and the incorporation of sulfur improves the ferromagnetism owing to the increased concentration of Zn vacancies, which may be stabilized by the doped sulfur ions. The adsorption capability of ZnO1−xSx nanoparticles has been significantly improved, and the process can be well described by the pseudo-first-order kinetic model and the Freundlich isotherm model. The mechanism has been confirmed to be due to the active sulfate groups existing in zinc oxysulfide nanoparticles.

Thermal tests of electronic units are critically important for the reliability validation and performance demonstration of spacecraft hardware. A tailoring equation like that provided by MIL-STD-1540s is necessary for the testing condition planning of these thermal tests, however, the tailoring equation provided by MIL-STD-1540s is mainly based on the fatigue data of solders. In this paper, a new test condition tailoring equation is proposed by introducing an integrated evaluating method for the fatigue acceleration exponent. The different thermo-mechanical fatigue mechanisms and different subsystem characteristics have been considered and discussed in the deducing of this new equation. The test precipitation efficiency (PE) of the new tailoring law has been analyzed and compared with that from the MIL-STD-1540 tailoring equations. The results are encouraging and reasonable.

Landslides are common phenomena in mountainous regions worldwide. Over the past two decades, catastrophic rockslides in mountainous regions have caused serious damage and fatalities. To develop effective preventive countermeasures, it is important to estimate the kinematic behavior of displaced masses after slope failures, such as the velocity, run-out distance, and extent. Discontinuous deformation analysis (DDA) is an appropriate tool to analyze the dynamics, kinematics, and deformability of a block assembly. Many studies have reported applications of DDA to kinematic analyses of rockslides on two-dimensional (2-D) terrain. However, because of the restrictions of numerical techniques, few kinematic analyses of rockslides on three-dimensional (3-D) terrain have been performed using DDA. This study developed a new DDA model for the analysis of rockslides on 3-D terrain. First, contact treatment techniques for the 3-D model were developed to create an accurate and efficient computational scheme. The new model was then verified by the benchmark tests on the four basic types of block motion on 3-D terrain. Finally, the new model was applied to a designed rockslide with complex terrain to demonstrate its practical applicability. The results indicate that the new 3-D DDA model is an effective tool to analyze 3-D rockslides and could potentially be used to optimize protection designs for rockslides.

With the rapid development of the energy internet, the transaction of distributed renewable energy (DRE) is playing an increasingly important role in the energy market. However, in the transaction model of distributed renewable energy combined with public blockchain technology, nodes in the trading network can join or leave the network at any time without any permission, which hinders the regulation of electricity institutions. Corresponding to the transaction principle, a distributed renewable energy transaction authentication mechanism based on consortium blockchain is proposed in this paper. First, certificate authority nodes were set in the transaction network to provide nodes with access authority by controlling the public keys and private keys of trading participants so that they can complete their identity authentication. Next, essential chaincodes in the transaction authentication were designed and deployed on a Hyperledger Fabric blockchain site, and a simulation experiment of a simple DRE transaction was used to elaborate the details on the transaction process. Finally, the proposed model was evaluated according to its performance and proved to be practical and effective.

Impulsive noise, generated by inverters and other equipment used in the field, tends to easily enter test channels in scenarios where continuous frequency conversion signals are employed to test the frequency response of electrohydraulic proportional valves. Interference caused by such noise reduces the signal-to-response ratio of response signals, thereby influencing the accuracy of the frequency response of proportional valves. To address this concern, in this article, an integrated filtering method that combines ensemble empirical mode decomposition with median filtering is proposed. The proposed method first preprocesses the response signals of the systems and subsequently obtains frequency-response diagrams using fast Fourier transforms. Simulation results demonstrate that the proposed method reduces the root mean square error associated with the amplitude–frequency characteristic curves of the proportional directional valve considered from 2.1 to 0.3, whereas that associated with phase–frequency characteristic curves is reduced from 78.0 to 1.4 with signal-to-noise ratios in the high-frequency band being of the order of –20 dB. Experimental results also reveal that the proposed method reduces the root mean square error of the amplitude–frequency characteristic curves of the proportional directional valve by 52.5% and that of the phase–frequency characteristic curves by 71.2%.

Semi-supervised learning can reduce the burden of manual label data and improve classification performance by learning with unlabelled data. However, due to the absence of label constraints, unlabelled data is usually ambiguous, which typically results in requiring large datasets to learn the correct feature space distribution. The inherently small sample characteristics of medical image datasets may make semi-supervised learning unstable, which may lead to mixed results and even degrade performance. The domain knowledge (DK) of the physician is of great value for disease diagnosis. In this paper, we propose to promote semi-supervised learning with DK and develop a DScGANS model (DScGAN (dual-path semi-supervised conditional generative adversarial networks) and S3VM (semi-supervised support vector machine)) to diagnose ultrasound thyroid nodules. DScGAN uses DK as a condition and multimodal ultrasound data for training. We concatenate the image representation of DScGAN learning and use it as the input of S3VM. DK will be used as a condition to constrain S3VM for thyroid nodule classification. The experimental results show that our proposed model can effectively avoid mixed results that may occur in semi-supervised learning with a small medical dataset with insufficient labels. Additionally, our model provides stable and advanced diagnostic performance and is potentially integrated into the thyroid ultrasound system.

The automatic and accurate diagnosis of thyroid nodules in ultrasound images is of great significance to reduce the workload and radiologists’ misdiagnosis rate. Although deep learning has shown strong image classification performance, the inherent limitations of medical images small dataset and time-consuming access to lesion annotations, leaving this work still facing challenges. In our study, a multi-task cascade deep learning model (MCDLM) was proposed, which integrates radiologists’ various domain knowledge (DK) and uses multimodal ultrasound images for automatic diagnosis of thyroid nodules. Specifically, we transfer the knowledge learned by U-net from the source domain to the target domain under the guidance of radiologist’ marks to obtain more accurate nodules’ segmentation results. We then quantify the nodules’ ultrasound features (UF) as conditions to assist the dual-path semi-supervised conditional generative adversarial network (DScGAN) in generating higher quality images obtaining more powerful discriminators. After that, we concatenate DScGAN learning’s image representation to train a supervised support vector machine (S3VM) for thyroid nodule classification. The experiment results on ultrasound images of 1030 patients suggest that the MCDLM model can achieve almost the same classification performance as the fully supervised learning (an accuracy of 90.01% and an AUC of 91.07%) using only about 35% of the full labeled dataset, which saves a lot of time and effort compared to traditional methods.

A simple method to prepare TiO2/g-C3N4 nanocomposite photocatalysts by atomic layer deposition (ALD) has been developed. A uniform ultra-thin TiO2 coating was coated conformally on g-C3N4 powders via ALD. After 500 °C annealing process, amorphous TiO2 turns into anatase nanocrystals and forms heterojunctions between TiO2 and g-C3N4, which greatly improves the separation efficiency of photo-generated carriers of g-C3N4. Moreover, an exfoliation phenomenon of g-C3N4 based on ALD is also observed with dramatically increased specific surface areas from 10.4 m2/g (g-C3N4) to 31.2 m2/g (annealed TiO2/g-C3N4), providing a new way for the exfoliation of layered materials. As a result, annealed 50TiO2/g-C3N4 nanocomposite exhibits the best photocatalytic activity with the methyl orange degradation efficiency of 98.2% in 90 min under visible light irradiation, much better than pure g-C3N4 with only 45% degradation efficiency. The first-order reaction rate constant of annealed TiO2/g-C3N4 nanocomposite is 0.0406 min−1 with the half-life period of only 17 min, which is 5.8 times higher than that of the pure g-C3N4 powders. The enhanced photocatalytic performance of annealed TiO2/g-C3N4 nanocomposites can be ascribed to the synergetic effect of heterojunctions between crystalline TiO2 and g-C3N4 and the increased specific surface areas. Above all, ALD may be a kind of promising and feasible method to fabricate g–C3N4–based nanocomposite powders for photocatalytic applications.

A-D-A types non-fullerene small molecule acceptors (NF-SMAs) have achieved excellent progress in recent years, while the development of series of new materials. Herein, a new NF-SMA, named BDSe-4F, based on linear benzo[1, 2-b:4, 5-b’] diselenophene with the difluorinated 5, 6-difluoro-3(dicyanomethylene) indanone (IC-2F) was synthesized and investigated. Due to the introduction of IC-2F, the intramolecular charge transfer is enhanced. Furtherly, the BDSe-4F exhibits a wider absorption from 600-800 nm in solution. From solution to film, the absorption spectrum shows an obvious red-shifted in the range of 800-900 nm and the maximum absorption peak red-shifted at 31 nm, suggesting that much stronger intermolecular interactions caused by non-covalent bond of F....S,F.... Se, and S....O. The BDSe-4F possesses good spectral absorption range and excellent molecular stacking, which beneficial to achieve high JSC and electron mobility. These results illustrate that the synergistic strategy of using benzo[1, 2-b:4, 5-b’] diselenophene core unit and IC-2F end group is a promising strategy to enhance performance in organic solar cells.

An effective precursor is a prerequisite and key to the success of atomic layer deposition (ALD). Currently, the design of more effective precursors is an important aspect of the development of ALD technology. In this review, theoretical design and computational screening methods for ALD precursors are discussed. Theoretical calculations can predict many properties of precursors, such as the bond strength between the metal and the ligand, the thermolysis energy and barrier, the chelation energy, the hydrolysis energy, the formation energy, and so on. Most of these calculated data are related to the stability and reactivity of the precursor, which can be used in the design and computational screening of new ALD precursors. In addition, precursor design and screening require consideration of the ALD reaction mechanism in order to predict the true reactivity of the precursor with the surface, namely the surface reactivity of the precursor, which reflects the essence of ALD technology. Such theoretical efforts are expected to provide guidance for the design of more effective precursors and thereby lead to an improvement of ALD applications.

Due to the impermeability of the blood-brain barrier and the nonselective distribution of drugs in the brain, the therapeutic access to intractable neurological disorders is challenging. In this study, dual brain-targeting polymersomes (POs) functionalized by transferrin and Tet-1 peptide (Tf/Tet-1-POs) promoted the transportation of curcumin into the brain and provided neuroprotection. The modification of the ligands that bind to the surface of POs was revealed by X-ray photoelectron spectroscopy analysis. The cell uptake of a coculture model of mouse brain capillary endothelial cells with neurons showed that the Tf/Tet-1-POs had significant transportation properties and possessed affinity for neurons. The pharmacokinetic analysis showed that the blood-brain barrier permeability-surface efficiency of the Tf/Tet-1-POs was 0.28 mL/h/g and that the brain tissue uptake rate (% ID/g) was 0.08, which were significant compared with the controls (P

Zr-Y jointly modified silicide coatings were prepared on an Nb-Ti-Si-Cr based ultrahigh temperature alloy by pack cementation process. The wear behaviors of both the base alloy and coatings were comparatively studied at room temperature and 800 °C using SiC balls as the counterpart. The Zr-Y jointly modified silicide coating is mainly composed of a thick (Nb,X)Si 2 outer layer and a thin (Ti, Nb) 5 Si 4 inner layer. The coatings possess much higher microhardness than the base alloy. The wear rates of both the base alloy and coatings increase with increasing the sliding loads. However, the coatings have much lower wear rates than the base alloy under the same sliding conditions. The coatings have superior anti-friction property, and can provide effective protection for the base alloy at both room temperature and 800 °C in air.

This paper extends three-dimensional discontinuous deformation analysis (3-D DDA) to model the frictional-cohesive failure behavior of geotechnical materials and structures. Firstly, a new contact detection scheme was developed to successfully identify the dominant sub-contacts and areas of the joints between arbitrarily shaped polyhedral blocks. Secondly, a modified joint contact model subjected to the Mohr-Coulomb failure criteria based on distributed cohesion instead of concentrated cohesion, was proposed to ensure the accuracy of the simulation by 3-D DDA. Thirdly, the extended 3-D DDA was verified by three examples, including joint contact detection, critical stability and failure mode of a system of polyhedral blocks. Finally, the complete failure process involving large displacement and rotation of multiple interaction blocks is exhibited dynamically. Overall, these examples exhibit that the extended 3-D DDA is now capable of accurately modeling the failure behavior of frictional-cohesive materials and structures, so as to optimize the material and structure stabilization or protection design.

Increasing global demands for energy storage in electric vehicles and the grid necessitate “beyond-lithium-ion” batteries that simultaneously exhibit high capacity, long-term cyclability, and excellent safety. Several candidates, most notably lithium–air and lithium–sulfur batteries, utilize lithium-metal anodes. Although the specific capacity of lithium metal is unrivaled (3860 mA h g−1), the capacity fade and risk of catastrophic failure must be overcome. Herein, we describe ultrathin, ionically conducting lithium aluminum sulfide (LixAlyS) coatings prepared on lithium-metal anodes by using atomic layer deposition, which stabilize the Li–electrolyte interface and reduce (up to five times) the interfacial impedance of lithium–metal anodes in contact with organic electrolyte. We demonstrate that these thin films effectively suppress dendrite formation and preserve a smooth, low-surface-area morphology for electrodeposited lithium metal, thereby doubling the lifetime of Li–Cu asymmetric cells.

Li4Ti5O12(LTO) and Li4Ti5O12/TiO2/Li0.4TiO2/C (LTO/C) composite were prepared by the electrospinning method using acetic acid, ethanol, butyl titanate, lithium acetate and PVP (K90) as the raw materials. The phase structure and the morphology were characterized by the X-ray diffraction (XRD) and the scanning electron microscopy (SEM), respectively. It was found that the specific capacity was 356mAh/g at 0.5C for the composite, which was higher than the theoretical specific capacity of the pure Li4Ti5O12 due to the inclusion of other phase. Moreover, the C-rate performance for the composite was also better than that of the pure Li4Ti5O12 resulting from the formation of carbon-based fiber structure. Electrochemical impedance spectra (EIS) revealed that the composite exhibited the improved electronic conductivity than that of Li4Ti5O12.