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Perturbation theory (PT) might be one of the most powerful and fruitful tools for both physicists and chemists, which has led to a wide variety of applications. Over the past decades, advances in quantum computing provide opportunities for alternatives to classical methods. Recently, a general quantum circuit estimating the low order PT corrections has been proposed. In this article, we revisit the quantum circuits for PT calculations, and develop the methods for higher order PT corrections of eigenenergy, especially the 3rd and 4th order corrections. We present the feasible quantum circuit to estimate each term in these PT corrections. There are two the fundamental operations in the proposed circuit. One approximates the perturbation terms, the other approximates the inverse of unperturbed energy difference. The proposed method can be generalized to higher order PT corrections. [ABSTRACT FROM AUTHOR]

Levitated diamond particles in high vacuum with internal spin qubits have been proposed for exploring macroscopic quantum mechanics, quantum gravity, and precision measurements. The coupling between spins and particle rotation can be utilized to study quantum geometric phase, create gyroscopes and rotational matter-wave interferometers. However, previous efforts in levitated diamonds struggled with vacuum level or spin state readouts. To address these gaps, we fabricate an integrated surface ion trap with multiple stabilization electrodes. This facilitates on-chip levitation and, for the first time, optically detected magnetic resonance measurements of a nanodiamond levitated in high vacuum. The internal temperature of our levitated nanodiamond remains moderate at pressures below 10−5 Torr. We have driven a nanodiamond to rotate up to 20 MHz (1.2 × 109 rpm), surpassing typical nitrogen-vacancy (NV) center electron spin dephasing rates. Using these NV spins, we observe the effect of the Berry phase arising from particle rotation. In addition, we demonstrate quantum control of spins in a rotating nanodiamond. These results mark an important development in interfacing mechanical rotation with spin qubits, expanding our capacity to study quantum phenomena. Levitated nanodiamonds containing NV centers promise applications in quantum technologies, but they require experiments in high vacuum. Here the authors report on-chip levitation of nanodiamonds in high vacuum using a surface ion trap, showing spin read-out and fast rotation above NV center spin dephasing time. [ABSTRACT FROM AUTHOR]

Due to the complex interactions between multiple infectious diseases, the spreading of diseases in human bodies can vary when people are exposed to multiple sources of infection at the same time. Typically, there is heterogeneity in individuals' responses to diseases, and the transmission routes of different diseases also vary. Therefore, this paper proposes an SIS disease spreading model with individual heterogeneity and transmission route heterogeneity under the simultaneous action of two competitive infectious diseases. We derive the theoretical epidemic spreading threshold using quenched mean-field theory and perform numerical analysis under the Markovian method. Numerical results confirm the reliability of the theoretical threshold and show the inhibitory effect of the proportion of fully competitive individuals on epidemic spreading. The results also show that the diversity of disease transmission routes promotes disease spreading, and this effect gradually weakens when the epidemic spreading rate is high enough. Finally, we find a negative correlation between the theoretical spreading threshold and the average degree of the network. We demonstrate the practical application of the model by comparing simulation outputs to temporal trends of two competitive infectious diseases, COVID-19 and seasonal influenza in China. [ABSTRACT FROM AUTHOR]

Highlights: High-quality large-area perovskite films are prepared using a solid–liquid two-step film formation method combined with CsBr modification for the buried interface and Urea additive for perovskite crystallization. The inverted perovskite solar modules' performance is enhanced to 20.56% in 61.56 cm2 with improved stability. A considerable efficiency gap exists between large-area perovskite solar modules and small-area perovskite solar cells. The control of forming uniform and large-area film and perovskite crystallization is still the main obstacle restricting the efficiency of PSMs. In this work, we adopted a solid–liquid two-step film formation technique, which involved the evaporation of a lead iodide film and blade coating of an organic ammonium halide solution to prepare perovskite films. This method possesses the advantages of integrating vapor deposition and solution methods, which could apply to substrates with different roughness and avoid using toxic solvents to achieve a more uniform, large-area perovskite film. Furthermore, modification of the NiOx/perovskite buried interface and introduction of Urea additives were utilized to reduce interface recombination and regulate perovskite crystallization. As a result, a large-area perovskite film possessing larger grains, fewer pinholes, and reduced defects could be achieved. The inverted PSM with an active area of 61.56 cm2 (10 × 10 cm2 substrate) achieved a champion power conversion efficiency of 20.56% and significantly improved stability. This method suggests an innovative approach to resolving the uniformity issue associated with large-area film fabrication. [ABSTRACT FROM AUTHOR]

While the monolayer sheet is well-established as a Mott-insulator with a finite energy gap, the insulating nature of bulk 1T-TaS2 crystals remains ambiguous due to their varying dimensionalities and alterable interlayer coupling. In this study, we present a unique approach to unlock the intertwined two-dimensional Mott-insulator and three-dimensional band-insulator states in bulk 1T-TaS2 crystals by structuring a laddering stack along the out-of-plane direction. Through modulating the interlayer coupling, the insulating nature can be switched between band-insulator and Mott-insulator mechanisms. Our findings demonstrate the duality of insulating nature in 1T-TaS2 crystals. By manipulating the translational degree of freedom in layered crystals, our discovery presents a promising strategy for exploring fascinating physics, independent of their dimensionality, thereby offering a "three-dimensional" control for the era of slidetronics. While monolayer of 1T-TaS2 is considered to be a Mott insulator, the nature of the bulk insulating state is debated. Here the authors introduce a ladder-type structures with fractional misalignment of adjacent layers, showing that it becomes a Mott insulator due to decoupling between the layers. [ABSTRACT FROM AUTHOR]

Perovskite photovoltaics, typically based on a solution-processed perovskite layer with a film thickness of a few hundred nanometres, have emerged as a leading thin-film photovoltaic technology. Nevertheless, many critical issues pose challenges to its commercialization progress, including industrial compatibility, stability, scalability and reliability. A thicker perovskite film on a scale of micrometres could mitigate these issues. However, the efficiencies of thick-film perovskite cells lag behind those with nanometre film thickness. With the mechanism remaining elusive, the community has long been under the impression that the limiting factor lies in the short carrier lifetime as a result of defects. Here, by constructing a perovskite system with extraordinarily long carrier lifetime, we rule out the restrictions of carrier lifetime on the device performance. Through this, we unveil the critical role of the ignored lattice strain in thick films. Our results provide insights into the factors limiting the performance of thick-film perovskite devices. The power conversion efficiencies of thick-film perovskite solar cells lag behind those with nanometre film thickness. Here, the authors rule out the restrictions of carrier lifetime on device performance and reveal the critical role of lattice strain in micron-scale thick perovskite films. [ABSTRACT FROM AUTHOR]

In scientific research, basic research that is both curiosity-driven and use-inspired is known as Pasteur's Quadrant. The research on the impact and attention of Pasteur's Quadrant is an essential research topic in academia. In view of the many milestone breakthroughs that Artificial Intelligence (AI) has brought to humanity, this paper delves into Pasteur's Quadrant in AI through the citation of papers by patents. We empirically analyse the scientific impact of 3322 patent-cited papers and 6587 non-patent-cited papers published from 1999 to 2013, where scientific impact is measured by scientific citations and usage counts. Our main results show that patent-cited papers have a stronger scientific impact than non-patent-cited papers, and this impact is further enhanced in conference publications than in journal publications. Further, the relationship between the multidimensional characteristics of patent citations and scientific impact is investigated in terms of patent-cited papers. We find an inverted U-shaped relationship between the intensity of a paper's patent citations and its scientific citations, as well as between the breadth of a paper's patent citations and its scientific citations. In addition, the patent citation lag of a paper negatively relates to its scientific impact. [ABSTRACT FROM AUTHOR]

Perovskite solar cells with the formula FA1−xCsxPbI3, where FA is formamidinium, provide an attractive option for integrating high efficiency, durable stability and compatibility with scaled-up fabrication. Despite the incorporation of Cs cations, which could potentially enable a perfect perovskite lattice1,2, the compositional inhomogeneity caused by A-site cation segregation is likely to be detrimental to the photovoltaic performance of the solar cells3,4. Here we visualized the out-of-plane compositional inhomogeneity along the vertical direction across perovskite films and identified the underlying reasons for the inhomogeneity and its potential impact for devices. We devised a strategy using 1-(phenylsulfonyl)pyrrole to homogenize the distribution of cation composition in perovskite films. The resultant p–i–n devices yielded a certified steady-state photon-to-electron conversion efficiency of 25.2% and durable stability.We added out-of-plane cations to homogenize the distribution of cations in perovskite films, resulting in a solar cell with improved efficiency and stability. [ABSTRACT FROM AUTHOR]

Modifying the exposed upper surface of perovskite solar cells (PSCs) has greatly contributed to improving their photovoltaic performance. The equally important buried interface (that is, the hidden bottom of perovskite film and the beginning of perovskite film crystallization) is much less studied due to great difficulties in tailoring it. Here we expose the large-area buried interface non-destructively for direct investigation. We find that the disordered beginning of the perovskite film growth deteriorates the buried interface. To address this issue, instead of using a passivator, we synthesize a transparent and conductive oxide perovskite (SrSnO3) to act as the electron transport layer. The high lattice matching enables a more ordered beginning of the growth of halide perovskite on the electron transport layer, avoiding the formation of a deteriorated buried interface. The constructed buried interface exhibits suppressed defects, strain, better crystallinity, reduced ion migration and fewer voids. The best performing PSCs deliver a power conversion efficiency of 25.17%. Moreover, PSCs with an initial power conversion efficiency of 24.4% maintain 90% of the original value after operating for 1,000 h. Employing a lattice-matched perovskite oxide as an electron transport layer allows optimizing the buried interface in perovskite solar cells. A maximum power conversion efficiency of 25.17% is achieved. Cells with an initial power conversion efficiency of 24.4% maintain 90% efficiency after operation for 1,000 h. [ABSTRACT FROM AUTHOR]

In order to overcome the disadvantages of contact measurement, time-consuming in traditional radial circular runout measurement, a non-contact measurement method based on machine vision technology is proposed in this paper. Using the image template matching and sub-pixel edge extraction techniques, the fine edge information of measured region is obtained. The rand sample consistency (RANSAC) algorithm is performed to filter the noise of edge data. Then, the least squares method is used for the parallel line fitting of two edges of measured region, and the reference axis of the shaft is gotten. The distance of measured point to the reference axis is defined as the radius at this rotating position, and the radius fluctuation at different rotational positions is the radial circular runout. The proposed method also allows random rotation of the measured shaft during the measuring process, and the high-precision-assisted rotation equipment is not essential, which enhances the convenience of the measuring equipment. [ABSTRACT FROM AUTHOR]

Optically active spin defects in van der Waals materials are promising platforms for modern quantum technologies. Here we investigate the coherent dynamics of strongly interacting ensembles of negatively charged boron-vacancy ( V B − ) centers in hexagonal boron nitride (hBN) with varying defect density. By employing advanced dynamical decoupling sequences to selectively isolate different dephasing sources, we observe more than 5-fold improvement in the measured coherence times across all hBN samples. Crucially, we identify that the many-body interaction within the V B − ensemble plays a substantial role in the coherent dynamics, which is then used to directly estimate the concentration of V B − . We find that at high ion implantation dosage, only a small portion of the created boron vacancy defects are in the desired negatively charged state. Finally, we investigate the spin response of V B − to the local charged defects induced electric field signals, and estimate its ground state transverse electric field susceptibility. Our results provide new insights on the spin and charge properties of V B − , which are important for future use of defects in hBN as quantum sensors and simulators. The boron vacancy center in hBN has been intensively studied, but its characterizations have remained limited. Here the authors achieve a 5-fold enhancement of coherence time using dynamical decoupling, which enables the direct estimation of defect concentration and its electric field susceptibility. [ABSTRACT FROM AUTHOR]

Highlights: The (011) facet has excellent charge transport properties achieving closer alignment of energy levels. By exploiting the (011) facet a device (0.06 cm2) and a module (29 cm2) achieved power conversion efficiencies of 25.24% and 21.12%, respectively. Perovskite crystal facets greatly impact the performance and stability of their corresponding photovoltaic devices. Compared to the (001) facet, the (011) facet yields better photoelectric properties, including higher conductivity and enhanced charge carrier mobility. Thus, achieving (011) facet-exposed films is a promising way to improve device performance. However, the growth of (011) facets is energetically unfavorable in FAPbI3 perovskites due to the influence of methylammonium chloride additive. Here, 1-butyl-4-methylpyridinium chloride ([4MBP]Cl) was used to expose (011) facets. The [4MBP]+ cation selectively decreases the surface energy of the (011) facet enabling the growth of the (011) plane. The [4MBP]+ cation causes the perovskite nuclei to rotate by 45° such that (011) crystal facets stack along the out-of-plane direction. The (011) facet has excellent charge transport properties and can achieve better-matched energy level alignment. In addition, [4MBP]Cl increases the activation energy barrier for ion migration, suppressing decomposition of the perovskite. As a result, a small-size device (0.06 cm2) and a module (29.0 cm2) based on exposure of the (011) facet achieved power conversion efficiencies of 25.24% and 21.12%, respectively. [ABSTRACT FROM AUTHOR]

Aiming at the problems of color compensation bias and loss of detail information in local areas of current underwater image enhancement methods, this paper proposes an underwater attenuation image enhancement method with adaptive color compensation and detail optimization. The method fully considers the attenuation level of each optical channel to guide the color correction based on the attenuation image, and introduces a brightness adjustment method to give the output image a good natural appearance. Gradient-oriented local contrast enhancement and multi-scale edge optimization methods are used to process the color- corrected image separately to obtain two clear images with balanced natural colors, high contrast and good preservation of detail information and then combine with the multi-scale fusion process Artifact-free image fusion is achieved. The experimental results on the UIEB dataset show that the method in this paper improves the UIQM and BRISQUE scores by 14.32% and 8.53%, respectively, and has fewer free parameters, which can effectively enhance attenuated image contrast, detail information and balance image color. In addition, the method in this paper has a complete feature point matching and target detection application, which can be used as a general framework for image preprocessing tasks. [ABSTRACT FROM AUTHOR]

A remarkable prediction of quantum field theory is that there are quantum electromagnetic fluctuations (virtual photons) everywhere, which leads to the intriguing Casimir effect. While the Casimir force between two objects has been studied extensively for several decades, the Casimir force between three objects has not been measured yet. Here, we report the experimental demonstration of an object under the Casimir force exerted by two other objects simultaneously. Our Casimir system consists of a micrometer-thick cantilever placed in between two microspheres, forming a unique sphere-plate-sphere geometry. We also propose and demonstrate a three-terminal switchable architecture exploiting opto-mechanical Casimir interactions that can lay the foundations of a Casimir transistor. Beyond the paradigm of Casimir forces between two objects in different geometries, our Casimir transistor represents an important development for controlling three-body virtual photon interactions and will have potential applications in sensing and information processing. Experimental studies of the Casimir effect have involved only interactions between two bodies so far. Here, the authors observe a micrometer-thick cantilever under the Casimir force exerted by microspheres from two sides simultaneously. [ABSTRACT FROM AUTHOR]

Cellular senescence is an irreversible cell arrest process, which is determined by a variety of complicated mechanisms, including telomere attrition, mitochondrial dysfunction, metabolic disorders, loss of protein homeostasis, epigenetic changes, etc. Cellular senescence is causally related to the occurrence and development of age-related disease. The elderly is liable to suffer from disorders such as neurodegenerative diseases, cancer, and diabetes. Therefore, it is increasingly imperative to explore specific countermeasures for the treatment of age-related diseases. Numerous studies on humans and mice emphasize the significance of metabolic imbalance caused by short telomeres and mitochondrial damages in the onset of age-related diseases. Although the experimental data are relatively independent, more and more evidences have shown that there is mutual crosstalk between telomeres and mitochondrial metabolism in the process of cellular senescence. This review systematically discusses the relationship between telomere length, mitochondrial metabolic disorder, as well as their underlying mechanisms for cellular senescence and age-related diseases. Future studies on telomere and mitochondrial metabolism may shed light on potential therapeutic strategies for age-related diseases. [ABSTRACT FROM AUTHOR]

Aiming at the noise disturbance of unwrapping phases of control points in the camera-projector calibration system, a random sample consensus (RANSAC) based plane fitting method is proposed to filter the phase noise in this paper. Different from the classical least squares method using all data, the points with noise will not be used to fit the plane in the proposed RANSAC method, which improves the accuracy of plane fitting. The proposed method suits for any two-dimensional (2D) calibration patterns, such as checkerboard or black dots with white background, which improves the flexibility of camera-projector system calibration. [ABSTRACT FROM AUTHOR]

The recently discovered spin-active boron vacancy (V B − ) defect center in hexagonal boron nitride (hBN) has high contrast optically-detected magnetic resonance (ODMR) at room-temperature, with a spin-triplet ground-state that shows promise as a quantum sensor. Here we report temperature-dependent ODMR spectroscopy to probe spin within the orbital excited-state. Our experiments determine the excited-state spin Hamiltonian, including a room-temperature zero-field splitting of 2.1 GHz and a g-factor similar to that of the ground-state. We confirm that the resonance is associated with spin rotation in the excited-state using pulsed ODMR measurements, and we observe Zeeman-mediated level anti-crossings in both the orbital ground- and excited-state. Our observation of a single set of excited-state spin-triplet resonance from 10 to 300 K is suggestive of symmetry-lowering of the defect system from D3h to C2v. Additionally, the excited-state ODMR has strong temperature dependence of both contrast and transverse anisotropy splitting, enabling promising avenues for quantum sensing. The negatively charged boron vacancy in hBN shows promise as a quantum sensor, but, until recently, the focus has been on its ground-state properties. Here, the authors report temperature-dependent spin-resonance optical spectroscopy of the orbital excited state. [ABSTRACT FROM AUTHOR]

Stem cell senescence and exhaustion are closely related to organ failure and individual aging, which not only induces age-related diseases, but also hinders stem cell applications in regenerative medicine. Thus, it's imminent to find effective ways to delay and retrieve stem cell senescence. Metabolic abnormalities are one of the main characteristics of age-associated declines in stem cell function. Understanding the underlying mechanisms may reveal potential strategies for ameliorating age-associated phenotypes and treating age-related diseases. This review focuses on recent advances in the association between metabolism including glucose, lipid, glutamine and NAD+ metabolism and stem cell senescence, as well as the other properties like proliferation and differentiation. Layers of studies are summarized to demonstrate how metabolism varies in senescent stem cells and how metabolic reprogramming regulates stem cell senescence. Additionally, we mentioned some recent progress in therapeutic strategies to rejuvenate dysfunctional aged stem cells. Finally, a brief conclusion about the prospect of metabolic regulation as a potential strategy for rescuing stem cell senescence is displayed. [ABSTRACT FROM AUTHOR]

The crucial component, bulky spacers, in two-dimensional Ruddlesden-Popper (2DRP) layered tin (Sn) perovskites are highly limited by halide ammonium salts, leading to the insufficient control of complex crystallization process due to the limited interaction between bulky spacers and 2DRP perovskite frameworks. Here, we report an ionic liquid-bulky spacer, butylammounium acetate (BAAcO), for constructing efficient and stable 2DRP Sn-based perovskite solar cells (PSCs). In contrast to the traditional halide ammonium bulky spacer, butylammounium iodide (BAI), the AcO−-functional group in BAAcO has a strong interaction with formamidine ions (FA+) and Sn2+. The inter-component interaction allows the formation of controllable intermediates for the favorable growth of smooth, dense, and highly oriented perovskite films. A PSC with power conversion efficiency of 10.36% (7.16% for BAI) is achieved, which is the highest report, along with improved stability with ∼90% retained after ∼600 h storage in N2 atmosphere without any encapsulation. [ABSTRACT FROM AUTHOR]

There are many eyewitness reports on unexpected water level change called 'strange tide' around the area of the radial sand ridges off the coast of Jiangsu Province, China, which has caused several fatal accidents in history. This study aims to prove whether a fast-moving atmospheric pressure disturbance can be a possible cause of the 'strange tide.' Based on the nonlinear shallow water model, a large number of scenarios for waves induced by a fast-moving pressure disturbance are numerically simulated and the maximum of the wave amplification ratio in each scenario is discussed. In each scenario, we assume an idealized pressure disturbance passing through the concerned area. The heading angle and translational speed of atmospheric disturbances are considered as variables. The results show that a fast-moving pressure disturbance can induce large wave level fluctuation in this area. In some special situations, the water level rise can be amplified more than 40 times than the water level change caused by a pressure disturbance with equivalent intensity under static equilibrium state. Both the heading angle and translational speed of atmospheric disturbances play a very important role in the occurrence of dangerous situation. The most dangerous combination of the two parameters is discussed, and the disaster prone locations in this area are identified considering the historical accidents and the numerical experiments. [ABSTRACT FROM AUTHOR]

The water–gas shift (WGS) reaction is an industrially important source of pure hydrogen (H2) at the expense of carbon monoxide and water1,2. This reaction is of interest for fuel-cell applications, but requires WGS catalysts that are durable and highly active at low temperatures3. Here we demonstrate that the structure (Pt1–Ptn)/α-MoC, where isolated platinum atoms (Pt1) and subnanometre platinum clusters (Ptn) are stabilized on α-molybdenum carbide (α-MoC), catalyses the WGS reaction even at 313 kelvin, with a hydrogen-production pathway involving direct carbon monoxide dissociation identified. We find that it is critical to crowd the α-MoC surface with Pt1 and Ptn species, which prevents oxidation of the support that would cause catalyst deactivation, as seen with gold/α-MoC (ref. 4), and gives our system high stability and a high metal-normalized turnover number of 4,300,000 moles of hydrogen per mole of platinum. We anticipate that the strategy demonstrated here will be pivotal for the design of highly active and stable catalysts for effective activation of important molecules such as water and carbon monoxide for energy production.A stable, low-temperature water–gas shift catalyst is achieved by crowding platinum atoms and clusters on α-molybdenum carbide; the crowding protects the support from oxidation that would cause catalyst deactivation. [ABSTRACT FROM AUTHOR]

In order to help financial users to invest, and to provide users with comprehensive and accurate information about financial securities, information about financial securities from multi-heterogeneous information is obtained. The characteristics of financial information are analyzed to provide valuable investment advice to users. According to the financial characteristics of the user's interest, the characteristics of the investor's interest are extracted from the heterogeneous information. Then, the multi-level model is proposed to analyze the characteristics. Through the multi-level model, the conversion of convertible bonds and the net value of closed funds are predicted. In the first level, based on the characteristics of convertible bonds and closed funds, three models of trend evaluation model, SVR (Support Vector Regression) model and neural network backpropagation network (BPN) model are used to predict financial characteristics. In the second level, the results produced by the three models in the first level are fused by the neural network. The third level optimizes the neural network based on the second level. The optimal initial weights and thresholds are selected by genetic algorithm to obtain better prediction results. The results show that the model can predict the characteristics of convertible bonds and closed funds more accurately. Therefore, the model provides a certain reference for financial users' investment. [ABSTRACT FROM AUTHOR]

Inter-city highway plays an important role in modern urban life and generates sensory data with spatio-temporal characteristics. Its current situation and future trends are valuable for vehicles guidance and transportation security management. As a domain routine analysis, daily detection of traffic hotspots faces challenges in efficiency and precision, because huge data deteriorates processing latency and many correlative factors cannot be fully considered. In this paper, an ensemble-learning based method for potential traffic hotspots detection is proposed. Considering time, space, meteorology, and calendar conditions, daily traffic volume is modeled on heterogeneous data, and trends predictive error can be reduced through gradient boosting regression technology. Using real-world data from one Chinese provincial highway, extensive experiments and case studies show our methods with second-level executive latency with a distinct improvement in predictive precision. [ABSTRACT FROM AUTHOR]

Two-dimensional Ruddlesden–Popper phase (2DRP) perovskites are known to exhibit improved photostability and environmental stability compared with their three-dimensional (3D) counterparts. However, fundamental questions remain over the interaction between the bulky alkylammoniums and the 2DRP perovskite framework. Here, we unambiguously demonstrate that a sulfur–sulfur interaction is present for a new bulky alkylammonium, 2-(methylthio)ethylamine hydrochloride (MTEACl). In addition to a weaker van der Waals interaction, the interaction between sulfur atoms in two MTEA molecules enables a (MTEA)2(MA)4Pb5I16 (n = 5) perovskite framework with enhanced charge transport and stabilization. The result is 2DRP perovskite solar cells with significantly improved efficiency and stability. Cells with a power conversion efficiency as high as 18.06% (17.8% certified) are achieved, along with moisture tolerance for up to 1,512 h (under 70% humidity conditions), thermal stability for 375 h (at 85 °C) and stability under continuous light stress (85% of the initial efficiency retained over 1,000 h of operation at the maximum power point). Two-dimensional perovskite solar cells have been engineered to be robust against moisture, high temperatures and light stress. [ABSTRACT FROM AUTHOR]

High-temperature oxidation and electroless nickel plating are two common surface modification processes to improve the wettability of SiC/Al interface. The structure and properties of SiC/SiO2/Al and SiC/Ni/Al interface layers were studied for the preparation of aluminum alloy drill pipe. Two kinds of 6.5%SiC/Al–Cu–Mg–Zn composite ingot were prepared using vacuum melting/casting method, and the added SiC particles in the composites were modified by high-temperature oxidation and electroless nickel plating, respectively. Analysis of structure demonstrates that the interface structures of composites ingot are SiC/SiO2/Al structure and SiC/Ni/Al structure, respectively. For SiC/SiO2/Al interface structure, a smooth and dense SiO2 film is well bonded to SiC and Al by chemical bonding. For SiC/Ni/Al interface structure, there is a very thin Ni film between SiC and Al and the bonding strength between Ni and Al is not so strong. Results of the performance test of the composites indicate that the tensile strength and compressive strength of the composites with SiC/SiO2/Al interface structure, respectively, increase by 7.51% and 24.90%, compared with the composites ingot with SiC/Ni/Al interface structure. [ABSTRACT FROM AUTHOR]

Uyghur text localization in complex background images is a significant research for Uyghur image content analysis. In this paper, we propose a robust Uyghur text localization method in complex background images and provide a CPU-GPU heterogeneous parallelization scheme. Firstly, a multi-color-channel enhanced maximally stable extremal region is used to extract components in images, which is robust to blur and low contrast. Secondly, a two-stage component classification system is used to filter out non-text components. Finally, a component connected graph algorithm is proposed to construct text lines. Experiments on the proposed dataset demonstrate that our algorithm compares favorably with the state-of-the-art algorithms when handling Uyghur texts. Besides, the heterogeneous parallel implementation achieves 12.5 times speedup. [ABSTRACT FROM AUTHOR]

Uyghur text detection is crucial to a variety of real-world applications, while little researches put their attention on it. In this paper, we develop an effective and efficient region-based convolutional neural network for Uyghur text detection in complex background images. The characteristics of the network include: (1) Three region proposal networks are used to improve the recall, which simultaneously utilize feature maps from different convolutional layers. (2) The overall architecture of our network is in the form of fully convolutional network, and global average pooling is applied to replace the fully connected layers in the classification and bounding box regression layers. (3) To fully utilize the baseline information, Uyghur text lines are detected directly by the network in an end-to-end fashion. Experiment results on benchmark dataset show that our method achieves an F-measure of 0.83 and detection time of 0.6 s for each image in a single K20c GPU, which is much faster than the state-of-the-art methods while keeps competitive accuracy. [ABSTRACT FROM AUTHOR]

Optical liquids are ideal materials for designing apochromatic lens due to their lower refractive index and higher Abbe numbers than those of the ordinary optical glasses. Based on the Buchdahl dispersion formula, the dispersion coefficient diagram of liquids and glasses is established. The liquid-glass combination lens(LGCL) with small secondary spectrum is obtained by calculating the combination structure with low dispersion liquid and glasses. The initial optical structure of the liquid-glass apochromatic lens(LGAL) can be obtained by replacing two glass lenses in an initial optical system with the LGCL. Using the multi-configuration optimization of ZEMAX, the liquid-glass achromatic zoom lens (LGAZL) can be designed by optimizing the LGAL. The LGAZL has an objective field of view ϕ63 mm-ϕ57 mm, an image field of view 8 mm, a working distance 240 mm and the zoom range of focal length 75-85 mm. The chromatic aberration and the secondary spectrum of the LGAZL are all less than 3 μm in the whole zoom range. [ABSTRACT FROM AUTHOR]

With the explosion of multimedia data, it is usual that different multimedia data often coexist in web repositories. Accordingly, it is more and more important to explore underlying intricate cross-media correlation instead of single-modality distance measure so as to improve multimedia semantics understanding. Cross-media distance metric learning focuses on correlation measure between multimedia data of different modalities. However, the existence of content heterogeneity and semantic gap makes it very challenging to measure cross-media distance. In this paper, we propose a novel cross-media distance metric learning framework based on sparse feature selection and multi-view matching. First, we employ sparse feature selection to select a subset of relevant features and remove redundant features for high-dimensional image features and audio features. Secondly, we maximize the canonical coefficient during image-audio feature dimension reduction for cross-media correlation mining. Thirdly, we further construct a Multi-modal Semantic Graph to find embedded manifold cross-media correlation. Moreover, we fuse the canonical correlation and the manifold information into multi-view matching which harmonizes different correlations with an iteration process and build Cross-media Semantic Space for cross-media distance measure. The experiments are conducted on image-audio dataset for cross-media retrieval. Experiment results are encouraging and show that the performance of our approach is effective. [ABSTRACT FROM AUTHOR]

The paper adopted the method of using "the first successfully matched table" for the data extraction which is correct in cases where the consolidated statement comes first and the parent company statement comes second. However, using this method some of the financial data used came from the parent company while some of the data came from consolidated statements. [Extracted from the article]

Background Metallic stents change permanently the mechanical properties of the vessel wall. However little is known about the implications of bioresorbable vascular scaffolds (BVS) on the vessel wall strain. Methods Patients (n = 53) implanted with an Absorb BVS that had palpographic evaluation at any time point [before device implantation, immediate after treatment, at short-term (6-12 months) or mid-term follow-up (24-36 months)] were included in the current analysis. The palpographic data were used to estimate the mean of the maximum strain values and the obtained measurements were classified using the Rotterdam classification (ROC) score and expressed as ROC/mm. Results Scaffold implantation led to a significant decrease of the vessel wall strain in the treated segment [0.35 (0.20, 0.38) vs. 0.19 (0.09, 0.29); P = 0.005] but it did not affect the proximal and distal edge. In patients who had serial palpographic examination the vessel wall strain continued to decrease in the scaffolded segment at short-term [0.20 (0.12, 0.29) vs. 0.14 (0.08, 0.20); P = 0.048] and mid-term follow-up [0.20 (0.12, 0.29) vs. 0.15 (0.10, 0.19), P = 0.024]. No changes were noted with time in the mechanical properties of the vessel wall at the proximal and distal edge. Conclusions Absorb BVS implantation results in a permanent alteration of the mechanical properties of the vessel wall in the treated segment. Long term follow-up data are needed in order to examine the clinical implications of these findings. [ABSTRACT FROM AUTHOR]

Many longitudinal studies in field settings present challenges due to selection bias and incomplete data. A motivating example is provided by an intervention study aimed at preventing HIV transmission among runaway youths housed at shelters in New York City. Two shelters with 167 youths received the intervention, and two shelters with 144 youths received the control treatment. The number of unprotected sexual acts in the prior three months for each youth was assessed at a baseline interview and (to the extent possible) at five follow-up time points. Among observed items, there is strong evidence of a lack of balance on baseline characteristics between the intervention and control groups; meanwhile, beyond occasional missing items among participants interviewed at baseline, there were three items about baseline characteristics added after the study began, resulting in a few items being missing on a large percentage of the study sample. Here, we outline two strategies for handling the complexities of this data set, both of which make use of propensity scores to address the imbalances across treatment groups. One approach relies on available cases and ad hoc choices to simplify the steps leading up to a linear mixed model analysis in SAS PROC MIXED; the other approach uses multiple imputation strategies to reflect uncertainty due to missing values in an analogous linear mixed model analysis. Ultimately we did not find substantial qualitative differences in this setting between the available-case and imputed-data approaches. But in both cases, we find that the considerable imbalance on covariates between treatment arms constrains the ability to draw inferences about the intervention effect, suggesting the importance of evaluating propensity-score distributions in quasi-experimental intervention research. [ABSTRACT FROM AUTHOR]

The original version of this Article contained an error in the spelling of the author Dan Credgington, which was incorrectly given as Dan Credington. This has now been corrected in both the PDF and HTML versions of the Article. [ABSTRACT FROM AUTHOR]

Organometal halide perovskites (OHP) are promising materials for low-cost, high-efficiency light-emitting diodes. In films with a distribution of two-dimensional OHP nanosheets and small three-dimensional nanocrystals, an energy funnel can be realized that concentrates the excitations in highly efficient radiative recombination centers. However, this energy funnel is likely to contain inefficient pathways as the size distribution of nanocrystals, the phase separation between the OHP and the organic phase. Here, we demonstrate that the OHP crystallite distribution and phase separation can be precisely controlled by adding a molecule that suppresses crystallization of the organic phase. We use these improved material properties to achieve OHP light-emitting diodes with an external quantum efficiency of 15.5%. Our results demonstrate that through the addition of judiciously selected molecular additives, sufficient carrier confinement with first-order recombination characteristics, and efficient suppression of non-radiative recombination can be achieved while retaining efficient charge transport characteristics. Crystal sizes play a vital role in pushing up the efficiency of organometal halide perovskites based LEDs. Here Ban et al. incorporate a molecular additive to control the crystallite distribution and phase separation in the perovskite devices, resulting in high external quantum efficiency of 15.5%. [ABSTRACT FROM AUTHOR]

Using poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as hole conductor, a series of inverted planar CH3NH3PbI3−xClx perovskite solar cells (PSCs) were fabricated based on perovskite annealed by an improved time-temperature dependent (TTD) procedure in a flowing nitrogen atmosphere for different time. Only after an optimum annealing time, an optimized power conversion efficiency of 14.36% could be achieved. To understand their performance dependence on annealing time, an in situ real-time synchrotron-based grazing incidence X-ray diffraction (GIXRD) was used to monitor a step-by-step gradual structure transformation from distinct mainly organic-inorganic hybrid materials into highly ordered CH3NH3PbI3 crystal during annealing. However, a re-crystallization process of perovskite crystal was observed for the first time during such an annealing procedure, which helps to enhance the perovskite crystallization and preferential orientations. The present GIXRD findings could well explain the drops of the open circuit voltage (Voc) and the fill factor (FF) during the ramping of temperature as well as the optimized power conversion efficiency achieved after an optimum annealing time. Thus, the present study not only illustrates clearly the decisive roles of post-annealing in the formation of solution-processed perovskite to better understand its formation mechanism, but also demonstrates the crucial dependences of device performance on the perovskite microstructure in PSCs. [ABSTRACT FROM AUTHOR]

Modulation of resistance by an external magnetic field, i.e. magnetoresistance effect, has been a long-lived theme of research due to both fundamental science and device applications. Here we report colossal positive magnetoresistance (CPMR) (>30,000% at a temperature of 2 K and a magnetic field of 9 T) discovered in degenerate semiconducting strontium titanite (SrTiO3) single crystals capped with ultrathin SrTiO3/LaAlO3 bilayers. The low-pressure high-temperature homoepitaxial growth of several unit cells of SrTiO3 introduces oxygen vacancies and high-mobility carriers in the bulk SrTiO3, and the three-unit-cell LaAlO3 capping layer passivates the surface and improves carrier mobility by suppressing surface-defect-related scattering. The coexistence of multiple types of carriers and inhomogeneous transport lead to the emergence of CPMR. This unit-cell-level surface engineering approach is promising to be generalized to others oxides, and to realize devices with high-mobility carriers and interesting magnetoelectronic properties. [ABSTRACT FROM AUTHOR]