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Nb3Sn is now recognized as the practical material for the high-field applications from 10 to 16 T, for particle accelerators, fusion and other related fields. However, the obtaining of high Jc in Nb3Sn presently contradicts one of the most important stability criteria: to keep a small filament size, which makes the stability issue particularly prominent. Large filament sizes frequently cause flux jumps in the conductor, making quench detection and protection more challenging for Nb3Sn magnets. In this work, we try to numerically simulate the flux jumps more accurately down to a filamentary scale. Based on the theory of superconducting dynamics, we have established a theoretical model to describe the magnetothermal instability of Nb3Sn wires by considering the superconductor flux dynamics, heat diffusion and temperature response. The preliminary analysis of the test results for LPF3 which is a 16-T hybrid common coil dipole magnet fabricated by Institute of High Energy Physics is conducted to study the causes of its quenching and the impact of flux jumps on the magnet.

The downward shortwave radiation (DSR) is an important part of the Earth’s energy balance, driving Earth’s system’s energy, water, and carbon cycles. Due to the harsh Antarctic environment, the accuracy of DSR derived from satellite and reanalysis has not been systematically evaluated over the transect of Zhongshan station to Dome A, East Antarctica. Therefore, this study aims to evaluate DSR reanalysis products (ERA5-Land, ERA5, MERRA-2) and satellite products (CERES and ICDR) in this area. The results indicate that DSR exhibits obvious monthly and seasonal variations, with higher values in summer than in winter. The ERA5-Land (ICDR) DSR product demonstrated the highest (lowest) accuracy, as evidenced by a correlation coefficient of 0.988 (0.918), a root-mean-square error of 23.919 (69.383) W m−2, a mean bias of −1.667 (−28.223) W m−2and a mean absolute error of 13.37 (58.99) W m−2. The RMSE values for the ERA5-Land reanalysis product at seven stations, namely Zhongshan, Panda 100, Panda 300, Panda 400, Taishan, Panda 1100, and Kunlun, were 30.938, 29.447, 34.507, 29.110, 20.339, 17.267, and 14.700 W m−2, respectively; with corresponding bias values of 9.887, −12.159, −19.181, −15.519, −8.118, 6.297, and 3.482 W m−2. Regarding seasonality, ERA5-Land, ERA5, and MERRA-2 reanalysis products demonstrate higher accuracies during spring and summer, while ICDR products are least accurate in autumn. Cloud cover, water vapor, total ozone, and severe weather are the main factors affecting DSR. The error of DSR products is greatest in coastal areas (particularly at the Zhongshan station) and decreases towards the inland areas of Antarctica.

A compact High Temperature Superconducting (HTS) cable, which is achieved by in-plane bending stacked REBCO tapes directly to realize the transposition(X-cable), has been designed and successfully fabricated by the Institute of High Energy Physics, Chinese Academy of Sciences (IHEP, CAS) for the application in high-field accelerator magnets. The high current carrying capacity and low AC loss of the X-cable have been investigated in our previous studies. In this article, the bendability of the X-cable was studied at 77 K and self-field, especially the minimum bending radius without performance degradation. The critical current (Ic) of each tape contained in the full-scale strand in the cable was powered individually at different bending radii. By analyzing the single tape's Ic as a function of bending radius, the test results demonstrate a good bending performance of the cable. The inter-tape resistance (Rc) is also investigated as a function of bending radius, which becomes more uniform and smaller after bending. Meanwhile, the dome-like shape of Rc explains that the copper film wrapped outside the stack can help share the current to improve the stability of the cable. The cable's parameters, bending performance test, and results analysis are presented in this work.

The Institute of High Energy Physics, Chinese Academy of Sciences (IEHP, CAS) proposed a compact ReBCO cable (named X-cable) which is implemented by in-plane bending ReBCO tapes to realize the transposition, and successfully fabricated a 10 m length prototype cable. The study on the mechanical properties of the cable is of great significance to its engineering application. Based on the finite element model, the stress-strain state of cable under different loads has been analyzed, which are used to predict the critical current performance of superconducting tapes in cable. This paper focuses on the possible failure mechanism of the X-cable under bending and transverse loads. Based on the established model, the critical bending radius of the x-cable is determined to be 20 mm. We analyzed the critical pressure and shear stress of the cable under lateral load, considering two possible scenarios that may occur during the manufacturing process. The above results can serve as a valuable reference for subsequent design of magnets and winding of coils.

The Superconducting magnet group at Institute of High Energy Physics (IHEP, China) has been engaging in the development of the high field dipole superconducting magnet with common-coil configuration and shell-based structure. A superconducting magnet named LPF3 was proposed to realize a bore field of 16 T with Nb3Sn (13 T) and HTS (3 T). Six Nb3Sn coils and two kinds of HTS inserted coils have been assembled in August, 2023. LTS coils (LPF3-LTS) will be firstly trained to 13 T then HTS coils will be energized afterwards. Instead of Bladder & Key technology, LPF3 used the commercial hydraulics devices to apply the pre-load force in horizontal and vertical direction for the first time. Strain gauges and Fiber Bragg Grating (FBG) sensors were applied to monitor the pre-loading effect of the magnet. The main design parameters, stress analysis results, assembly procedure and strain measurement results will be presented.

R&D of high field accelerator magnets is ongoing at the Institute of High Energy Physics, Chinese Academy of Sciences (IHEP, CAS) for pre-study of the next-generation high energy colliders like Super Proton-Proton Collider (SPPC), Future Circular Collider (FCC) and etc. A 12.47-T main field at 4.2 K has been attained in 2021 within two 14-mm apertures of LPF1-U, a superconducting model dipole magnet with Nb3Sn & NbTi combined common-coil configuration. Based on the experiences mastered in the LPF1 series magnets, a 16-T high field dipole magnet named LPF3 has been designed, fabricated and is in the performance test process. LPF3 is also a combined magnet with six racetrack Nb3Sn coils outside, expected to provide a 13-T main field within two 50-mm apertures, and with inserted HTS coils to enhance the field up to 16 T or even higher. The 13-T Nb3Sn dipole magnet, named LPF3-LTS, incorporates a graded common-coil configuration to enhance superconductor efficiency. The optimization of coil layouts includes varying bending radii (BR) and lengths of straight sections (LSS) to mitigate field accumulation in the outer four coils near the central posts and coil ends, respectively. Several Rutherford cables over 200 meters were fabricated for the coils winding, and with the maximum strands count of 42. The support structure for LPF3-LTS has adopted a shell-based design, with an improved “Bladder & Key” technology. Dedicated hydraulic pistons were investigated and utilized to replace the traditional bladders. The main design characteristics, fabrication process and some preliminary test results of the magnet are presented in this paper.

On the basis of the successful development of a high field dipole magnet named LPF1-U, which reached a peak field of 12.47 T in 2021, the new magnet LPF3 with an expected field of over 13 T in the two 50-mm apertures has been designed and fabricated at IHEP. The magnet is developed in a common-coil configuration with six flat racetrack Nb3Sn coils, as well as High Temperature Superconducting (HTS) insert coils in the center to further enhance the field to 16 T or more. The Nb3Sn coils are designed to provide a 13 T main field at the operating current of 7580 A. The quench protection of the Nb3Sn coils is significantly important and challenging because of the much larger magnet apertures (50 mm) and stored energy (2155 kJ). Finally, the method of CLIQ (coupling-loss induced quench protection system) together with varistor is adopted to accelerate the propagation of quench in the magnet and control the hotspot temperature. This article describes the design of the optimized quench protection scheme, the model and the simulation results. The experiment test results are also analyzed and discussed in this article.

The high temperature superconductivity (HTS) technology present itself a bright future to be used in a flywheel energy storage system (FESS). In addition to the characteristics of conventional flywheel energy storage systems, the self-stability of high temperature superconducting maglev enables the suspension bearing to completely eliminate external control, improving the efficiency and stability of the whole system. And superconducting flywheel energy storage system can effectively eliminate the loss caused by mechanical friction and the electrical loss caused by resistance. In this paper, a superconducting flywheel system which is suspended and self-stabilized through the meticulous design of a high magnetic field is presented. The most obvious advantages are the reduction of mechanical friction, the use of Lorentz force to provide centripetal force instead of relying on mechanical limit of materials, and a higher speed than traditional flywheels. The optimization of the field distribution as well as the HTS coil of the flywheel is discussed. Subsequently, the energy storage efficiency, power density, energy ratio and suspension force of the flywheel are analyzed and compared in detail.

Strong H-tensors play a significant role in identifying the positive definiteness of an even-order real symmetric tensor. In this paper, first, an improved iterative algorithm is proposed to determine whether a given tensor is a strong H-tensor, and the validity of the iterative algorithm is proved theoretically. Second, the iterative algorithm is employed to identify the positive definiteness of an even-order real symmetric tensor. Finally, numerical examples are presented to illustrate the advantages of the proposed algorithm.

In the new concept design of the circular electron positron collider detector, the magnet should be an ultrathin HTS solenoid with maximum radiation transparency. A novel aluminum-stabilized stacked REBCO tape cable (ASTC) was proposed and developed. The advantages of aluminum's high residual resistivity ratio, high thermal conductivity, and high transparency for particles, combined with the advantages of REBCO tape's high engineering current density, high strength and large temperature margin, constitute a suitable cable option for future detector magnets. The ASTC uses REBCO tapes in a stacked structure, which are wrapped and bound with metal tapes, and then covered with aluminum stabilizer by coextrusion processing. By optimizing the process parameters, such as preheating temperature, extrusion speed, Al outer layer thickness, and improving the internal structure of the cable, the critical current of the ASTC prototype cable is increased to 905 A@ 77 K, self-field. The degradation of the tape is less than 20%. This article presents the development process of the ASTC cable, discusses the challenges encountered during cable processing, and proposes corresponding solutions.

Flexible pressure sensors are devices that mimic the sensory capabilities of natural human skin and enable robots to perceive external stimuli. One of the main challenges is maintaining high sensitivity over a broad linear pressure range due to poor structural compressibility. Here, we report a flexible pressure sensor with an ultrahigh sensitivity of 153.3 kPa–1and linear response over an unprecedentedly broad pressure range from 0.0005 to 1300 kPa based on interdigital-shaped, multigradient architectures, featuring modulus, conductivity, and microstructure gradients. Such multigradient architectures and interdigital-shaped configurations enable effective stress transfer and conductivity regulation, evading the pressure sensitivity–linear range trade-off dilemma. Together with high pressure resolution, high frequency response, and good reproducibility over the ultrabroad linear range, proof-of-concept applications such as acoustic wave detection, high-resolution pressure measurement, and healthcare monitoring in diverse scenarios are demonstrated.

Metal film-based stretchable conductors are essential elements of flexible electronics for wearable, biomedical, and robotic applications, which require strain-insensitive high conductivity over a wide strain range and excellent cyclic stability. However, they suffer from serious electrical failure under monotonic and cyclic tensile loading at a small strain due to the uncontrolled film cracking behavior. Here, we propose a novel in-plane crack control strategy of engineering hierarchical microstructures to achieve outstanding electromechanical performance viaharnessing the strain distribution in metal films. The wrinkles delay the crack initiation at undercuts which should be the most vulnerable sites during the stretching process. The surface protrusions/grooves/undercuts inhibit the crack propagation because of the effective strain redistribution. In addition, hierarchical microstructures significantly improve cyclic stability due to the strong interfacial adhesion and stable crack patterns. The metal film-based conductors exhibit ultrahigh strain-insensitive conductivity (1.7 × 107S m−1), negligible resistance change (ΔR/R0= 0.007) over an ultra-wide strain range (>200%), and excellent cyclic strain durability (>15 000 cycles at 100% strain). A range of metal films was explored to establish the universality of this strategy, including ductile copper and silver, as well as brittle molybdenum and high entropy alloy. We demonstrate the strain-insensitive electrical functionality of a metal film-based conductor in a flexible light-emitting diode circuit.

In this work, the phase stability of non-equiatomic Fe50Mn30Co10Cr10and Fe50Mn30Co10Ni10high entropy alloys (HEAs) under strong constraining conditions as well as its effect on the mechanical properties were comparatively studied in the magnetron sputtered Cu/Fe50Mn30Co10Cr10and Cu/Fe50Mn30Co10Ni10nanolaminates with the layer thickness hranging from 5 to 150 nm. During the deposition process, the size-driven hexagonal close packed (HCP) to face-centered cubic (FCC) phase transformation occurs in the Fe50Mn30Co10Cr10layers as h< 25 nm due to the nanolayer constraining and template effects. Meanwhile, the stress-driven HCP-to-FCC phase transformation also occurs in the Cu/Fe50Mn30Co10Cr10nanolaminates during the indentation deformation, which is attributed to the nucleation of stacking faults that could serve as the nuclei for phase transformation. However, the Fe50Mn30Co10Ni10layers maintain stable microstructure without size-driven nor stress-driven phase transformation. With reducing h, both the Cu/HEA nanolaminates exhibit a transition from h-independent to h-dependent ultrahigh hardness, as elucidated by the partial dislocation-mediated mechanisms. In particular, the normalized hardness of Cu/Fe50Mn30Co10Cr10nanolaminates represented by the ratio of measured hardness to predicted hardness from the rule-of-mixture is more superior to conventional Cu-based bimetal nanolaminates. These findings provide a new perspective to tailor the phase transformation of HEAs and thereby enhance their strength and plasticity.

•Global air quality has experienced a shift from lightly polluted to clean conditions.•Trends in type-dependent AODs related to aerosol particle properties were examined.•SAOD and SPAOD play a leading role in driving interannual variability in land TAOD.

Metal film-based stretchable strain sensors hold great promise for applications in various domains, which require superior sensitivity-stretchability-cyclic stability synergy. However, the sensitivity-stretchability trade-off has been a long-standing dilemma and the metal film-based strain sensors usually suffer from weak cyclic durability, both of which significantly limit their practical applications. Here, we propose an extremely facile, low-cost and spontaneous strategy that incorporates topological gradients in metal film-based strain sensors, composed of intrinsic (grain size and interface) and extrinsic (film thickness and wrinkle) microstructures. The topological gradient strain sensor exhibits an ultrawide stretchability of 100% while simultaneously maintaining a high sensitivity at an optimal topological gradient of 4.5, due to the topological gradients-induced multistage film cracking. Additionally, it possesses a decent cyclic stability for >10 000 cycles between 0 and 40% strain enabled by the gradient-mixed metal/elastomer interfaces. It can monitor the full-range human activities from subtle pulse signals to vigorous joint movements.

Telomeres are the physical ends of linear chromosomes. They are composed of short repeating sequences (such as TTGGGG in the G-strand for Tetrahymena thermophila) of double-stranded DNA with a single-strand 3′ overhang of the G-strand and, in humans, the six shelterin proteins: TPP1, POT1, TRF1, TRF2, RAP1 and TIN21,2. TPP1 and POT1 associate with the 3′ overhang, with POT1 binding the G-strand3and TPP1 (in complex with TIN24) recruiting telomerase via interaction with telomerase reverse transcriptase5(TERT). The telomere DNA ends are replicated and maintained by telomerase6, for the G-strand, and subsequently DNA polymerase α–primase7,8(PolαPrim), for the C-strand9. PolαPrim activity is stimulated by the heterotrimeric complex CTC1–STN1–TEN110–12(CST), but the structural basis of the recruitment of PolαPrim and CST to telomere ends remains unknown. Here we report cryo-electron microscopy (cryo-EM) structures of TetrahymenaCST in the context of the telomerase holoenzyme, in both the absence and the presence of PolαPrim, and of PolαPrim alone. TetrahymenaCtc1 binds telomerase subunit p50, a TPP1 orthologue, on a flexible Ctc1 binding motif revealed by cryo-EM and NMR spectroscopy. The PolαPrim polymerase subunit POLA1 binds Ctc1 and Stn1, and its interface with Ctc1 forms an entry port for G-strand DNA to the POLA1 active site. We thus provide a snapshot of four key components that are required for telomeric DNA synthesis in a single active complex—telomerase-core ribonucleoprotein, p50, CST and PolαPrim—that provides insights into the recruitment of CST and PolαPrim and the handoff between G-strand and C-strand synthesis.

Negative Air Ions (NAIs), essential for environmental and human health, facilitate air purification and offer antimicrobial benefits. Our study achieves hourly estimations of NAIs using a machine learning framework, developed from a multi‐layer selection pipeline of over 200 variables, to identify the key determinants critical for adapting to high‐resolution NAIs dynamics. Addressing site sparsity and NAIs volatility, we introduced a hybrid stacking incorporating pseudo sites generated from Kriging Spatiotemporal Augmentation (KSTA) to mitigate spatial overfitting. Our approach, validated in Zhejiang, China, demonstrates exceptional accuracy, achieving R2values of 0.90 (sample‐based), 0.85 (temporal‐based), and 0.79 (site‐based). This work not only sheds light on NAIs behavior in relation to diurnal shifts, land use, and environmental events, but also integrates a health grading system, enhancing public health strategies through precise air quality assessment. Our study advances the environmental science by developing a machine‐learning model capable of estimation the hourly concentrations of negative air ions (NAIs) across Zhejiang Province, China. NAIs, vital for air purification and human health, are significantly related to environmental conditions. Taking advantage of a novel approach that reduces errors commonly seen in similar models, we provide a highly accurate, hour‐by‐hour analysis of air quality. Our research goes beyond mere prediction; it investigates how various factors like vegetation, soil type, and weather events influence NAI levels. The insights gained offer a comprehensive view of how NAI distribution changes over time and across different landscapes, informing environmental policy and public health strategies with precise air quality assessments. This study contributes significantly to the field by introducing an essential tool for continuous environmental monitoring, thereby facilitating more effective decision‐making in environmental and public health sectors. A hybrid stacking machine learning framework shows superior accuracy (R2= 0.90), combing a filter pipeline dealing with more than 200 variablesKriging Spatiotemporal Augmentation (KSTA) as a pseudo‐label strategy to resolve spatial overfitting due to sparse sitesAn hourly estimate of NAIs reveals NAIs dynamics correlations with environmental factors and land use, supporting public health policy A hybrid stacking machine learning framework shows superior accuracy (R2= 0.90), combing a filter pipeline dealing with more than 200 variables Kriging Spatiotemporal Augmentation (KSTA) as a pseudo‐label strategy to resolve spatial overfitting due to sparse sites An hourly estimate of NAIs reveals NAIs dynamics correlations with environmental factors and land use, supporting public health policy

Human telomerase is a RNA–protein complex that extends the 3′ end of linear chromosomes by synthesizing multiple copies of the telomeric repeat TTAGGG1. Its activity is a determinant of cancer progression, stem cell renewal and cellular aging2–5. Telomerase is recruited to telomeres and activated for telomere repeat synthesis by the telomere shelterin protein TPP16,7. Human telomerase has a bilobal structure with a catalytic core ribonuclear protein and a H and ACA box ribonuclear protein8,9. Here we report cryo-electron microscopy structures of human telomerase catalytic core of telomerase reverse transcriptase (TERT) and telomerase RNA (TER (also known as hTR)), and of telomerase with the shelterin protein TPP1. TPP1 forms a structured interface with the TERT-unique telomerase essential N-terminal domain (TEN) and the telomerase RAP motif (TRAP) that are unique to TERT, and conformational dynamics of TEN–TRAP are damped upon TPP1 binding, defining the requirements for recruitment and activation. The structures further reveal that the elements of TERT and TER that are involved in template and telomeric DNA handling—including the TEN domain and the TRAP–thumb helix channel—are largely structurally homologous to those in Tetrahymenatelomerase10, and provide unique insights into the mechanism of telomerase activity. The binding site of the telomerase inhibitor BIBR153211,12overlaps a critical interaction between the TER pseudoknot and the TERT thumb domain. Numerous mutations leading to telomeropathies13,14are located at the TERT–TER and TEN–TRAP–TPP1 interfaces, highlighting the importance of TER–TERT and TPP1 interactions for telomerase activity, recruitment and as drug targets.

The introduction of solubilizing additives has historically been an attractive approach to address the ever-growing proportion of poorly water-soluble drug (PWSD) compounds within the modern drug discovery pipeline. Lipid-formulations, and more specifically micelle formulations, have garnered particular interest because of their simplicity, size, scalability, and avoidance of solid-state limitations. Although micelle formulations have been widely utilized, the molecular mechanism of drug solubilization in surfactant micelles is still poorly understood. In this study, a series of modern nuclear magnetic resonance (NMR) methods are utilized to gain a molecular-level understanding of intermolecular interactions and kinetics in a model system. This approach enabled the understanding of how a PWSD, 17β-Estradiol (E2), solubilizes within a nonionic micelle system composed of polysorbate 80 (PS80). Based on one-dimensional (1D) 1H chemical shift differences of E2 in PS80 solutions, as well as intermolecular correlations established from 1D selective nuclear Overhauser effect (NOE) and two-dimensional NOE spectroscopy experiments, E2 was found to accumulate within the palisade layer of PS80 micelles. A potential hydrogen-bonding interaction between a hydroxyl group of E2 and a carbonyl group of PS80 alkane chains may allow for stabilizing E2–PS80 mixed micelles. Diffusion and relaxation NMR analysis and particle size measurements using dynamic light scattering indicate a slight increase in the micellar size with increasing degrees of supersaturation, resulting in slower mobility of the drug molecule. Based on these structural findings, a theoretical orientation model of E2 molecules with PS80 molecules was developed and validated by computational docking simulations.

Medium Mn steel was metal inert gas (MIG) welded with NiCrMo-3 and 307Si filler wires. The effect of filler wires on the microstructure and mechanical properties of joint was investigated, and the carbide precipitates were contrastively discussed. The results revealed that the microstructure of weld metal, heat-affected zone and base metal are austenite. Obvious grain coarsening occurred in the heat-affected zone (HAZ), and the maximum grain size grew up to 160 μm. In HAZ, C and Cr segregated at grain boundaries, the carbides was identified as Cr 7 C 3. The dispersive (Nb, Mo)C phase was also found in weld metal with NiCrMo-3 filler wire. All the welded joints failed in HAZ during tensile tests. The tensile strength of welded joint with NiCrMo-3 filler wire was 675 MPa, which is much higher than that with 307Si filler wire. In comparison to base metal, higher microhardness and lower impact toughness were obtained in HAZ for these two welded joints, which was attributed to the precipitation of Cr 7 C 3 phase and grain coarsening. The impact toughness around the fusion line is the worst for these two welded joints. [ABSTRACT FROM AUTHOR]

Telomerase is unique among the reverse transcriptases in containing a noncoding RNA (known as telomerase RNA (TER)) that includes a short template that is used for the processive synthesis of G-rich telomeric DNA repeats at the 3′ ends of most eukaryotic chromosomes1. Telomerase maintains genomic integrity, and its activity or dysregulation are critical determinants of human longevity, stem cell renewal and cancer progression2,3. Previous cryo-electron microscopy structures have established the general architecture, protein components and stoichiometries of Tetrahymenaand human telomerase, but our understandings of the details of DNA–protein and RNA–protein interactions and of the mechanisms and recruitment involved remain limited4–6. Here we report cryo-electron microscopy structures of active Tetrahymenatelomerase with telomeric DNA at different steps of nucleotide addition. Interactions between telomerase reverse transcriptase (TERT), TER and DNA reveal the structural basis of the determination of the 5′ and 3′ template boundaries, handling of the template–DNA duplex and separation of the product strand during nucleotide addition. The structure and binding interface between TERT and telomerase protein p50 (a homologue of human TPP17,8) define conserved interactions that are required for telomerase activation and recruitment to telomeres. Telomerase La-related protein p65 remodels several regions of TER, bridging the 5′ and 3′ ends and the conserved pseudoknot to facilitate assembly of the TERT–TER catalytic core.

Metastable high entropy alloys (HEAs) and amorphous metallic glasses (MGs), with the chemical disordered character, are intensively studied due to their excellent performance. Here, we introduce Cu to separately constrain these two metastable materials and comparatively investigate their deformation behaviors and mechanical properties of Cu/HEA FeCoCrNi and Cu/MG CuZr nanolaminated micropillars in terms of intrinsic layer thickness h and extrinsic pillar diameter D. The metastable HEA layers, as the hard phase in Cu/HEA micropillars, are stable and dominate the deformation, while transformation (crystallization) occurs in MG which plays a minor role in deformation of Cu/MG micropillars. The h -controlled deformation mode transits from the D -independent homogenous-like deformation at large h to the D -dependent shear banding at small h in both Cu/HEA and Cu/MG micropillars. Although both Cu/HEA and Cu/MG micropillars exhibit a maximum strain hardening capability controlled by h , the former manifests much lower hardening capability compared with the latter. The intrinsic size h and extrinsic size D have a strong coupling effect on the strength of Cu/HEA and Cu/MG micropillars. The strength of strength of Cu/HEA micropillars exhibits the D -dependent transition from "smaller is stronger" to "smaller is weaker" with increasing h. By contrast, the strength of Cu/MG micropillars exhibits the transition from bulk-like D -independent behavior at large h to small volume D -dependent behavior (smaller is stronger) at small h. [ABSTRACT FROM AUTHOR]

Service component selection is a core problem in software development process. With an enormous number of components available, it is often difficult for the developer to select the most appropriate one, as he or she might not be aware of all the possible business scenes ahead of time. Taking these challenges into consideration, we propose a deep learning-based system that automatically recommends service components based on component selection history during the software development process. We employ a sequential model with two long short-term memory (LSTM) layers and two fully connected layers, using SoftMax as an activation function, to predict the next service component. The model was trained, validated and tested on dataset with more than 120,000 examples from a real-world software company. The proposed network outperforms the baseline methods in terms of the evaluation criteria. In addition, the model results were deployed in a real-world software tool and gave positive feedback.

High entropy alloys (HEAs) have attracted extensive attention due to their excellent properties in harsh environments. Here, we introduced the HEA NbMoTaW into the laminated structure to synthesize the Cu/HEA nanolami-nates (NLs) with equal layer thickness hspanning from 5 to 100 nm, and comparatively investigated the size dependent mechanical properties and plastic deformation. The experimental results demonstrated that the hardness of Cu/HEA NLs increased with decreasing h, and reached a plateau at h≤ 50 nm, while the strain rate sensitivity munexpectedly went through a maximum with reducing h. The emergence of maximum mresults from a transition from the synergetic effect of crystalline constituents to the competitive effect between crystalline Cu and amorphous-like NbMoTaW. Micro-structural examinations revealed that shear banding caused by the incoherent Cu/HEA interfaces occurred under severe deformation, and the soft Cu layers dominated plastic deformation of Cu/HEA NLs with large h.

The Beijing government implemented a number of clean air action plans to improve air quality in the last 10 years, which contributed to changes in the concentration of fine particles and their compositions. However, quantifying the impacts of these interventions is challenging as meteorology masks the real changes in observed concentrations. Here, we applied a machine learning technique to decouple the effect of meteorology and evaluate the changes in the chemistry of nonrefractory PM1(particulate matter less than 1 μm) in winter 2007, 2016, and 2017 as a result of the clean air actions. The observed mass concentrations of PM1were 74.6, 90.2, and 36.1 μg m–3in the three winters, while the deweathered concentrations were 74.2, 78.7, and 46.3 μg m–3, respectively. The deweathered concentrations of PM1, organics, sulfate, ammonium, chloride, SO2, NO2, and CO decreased by −38, −46, −59, −24, −51, −89, −16, and −52% in 2017 in comparison to 2007. On the contrary, the deweathered concentration of nitrates increased by 4%. Our results indicate that the clean air actions implemented in 2017 were highly effective in reducing ambient concentrations of SO2, CO, and PM1organics, sulfate, ammonium, and chloride, but the control of nitrate and PM1organics remains a major challenge.

In 2013, China issued the “Action Plan for the Prevention and Control of Air Pollution” (“Ten Statements of Atmosphere”) and implemented a series of pollution reduction measures from 2013 to 2017. In key regions of China, the mass concentrations of particulate matter with aerodynamic equivalent diameters less than 2.5 µm (PM2.5) have dropped significantly. However, the contributions of meteorological changes to PM2.5reduction are largely uncertain, which has attracted particular concern from the government and the public. Here, we investigated the impact of large-scale and boundary layer (BL) meteorological conditions on aerosol pollution and estimated the contributions of meteorological changes to PM2.5reduction based on in-depth analysis and diagnosis of various observed meteorological elements and an integrated pollution-linked meteorological index (PLAM, which is approximately and linearly related to PM mass concentration). In this study, we found that the meteorological conditions worsened in 2014 and 2015 and improved in 2016 and 2017 relative to those in 2013 in key regions in China. In 2017 relative to 2013, only ∼5% (approximately 13% of the total PM2.5decline) of the 39.6% reduction in PM2.5mass concentrations can be attributed to meteorological changes in the Beijing-Tianjin-Hebei (BTH) region, and only ∼7% (approximately 20% of the total PM2.5decline) of the 34.3% reduction can be attributable to meteorological changes in the Yangtze River Delta (YRD) region. Overall, the PM2.5reduction due to meteorological improvement is much lower than the observed PM2.5reduction in these areas, which indicates that emission reduction during the five-year implementation of the “Ten Statements of Atmosphere” is the dominant factor in the improvement in air quality. The changes in meteorology and climate are conducive to PM2.5reduction but do not dominate the substantial improvement in air quality. Similar to the above regions, in the Pearl River Delta (PRD) region, the impact of meteorological changes on the annual averaged PM2.5concentration from 2013 to 2017 was relatively weak, and the PM2.5reduction was mainly due to emission reductions. During winter 2017 (January, February, and December of this year), the meteorological conditions improved ∼20% in the BTH region (observed total PM2.5reduction: 40.2%) and ∼30% in the YRD region (observed total PM2.5reduction: 38.2%) relative to those in 2013, showing the meteorological factors played more important role in the decrease of PM2.5in winter of these years in the two regions, respectively. The meteorological conditions in winter 2016 were 14% better than those in winter 2017, but the PM2.5reduction in winter 2016 was still less than that in winter 2017, reinforcing the significant contributions of the increasing efforts to reduce PM2.5emissions in 2017. The substantial progress of strict emission measures was also confirmed by a comparison of several persistent heavy aerosol pollution episodes (HPEs) with similar meteorological conditions. It is found that the decrease of PM2.5mass caused by emission reduction increases year by year, especially the decrease of PM2.5concentration in 2016 and 2017. In China, HPEs mainly occur in winter, when meteorological conditions are approximately 40–100% worse than in other seasons. This worsening is partly due to the harbor effect of high topography, including downdrafts and the weak wind zone, and partly due to the increasingly stable regional BL structure caused by climate warming. For the formation of HPEs, it occurred under regional stagnant and stable conditions associated with upper-level circulation patterns, including the zonal westerly winds type and high-pressure ridges. After pollution formation, PM2.5with mass accumulated to a certain degree can further worsen the BL meteorological conditions. The feedback effect associated with worsening conditions dominates PM2.5mass explosive growth. In the context of high air pollutant emissions in China, unfavorable meteorological conditions are the necessary external conditions for the formation and accumulation of HPEs. Therefore, reducing aerosol pollution significantly during the earlier transport stage is critical in reducing persistent HPEs. Currently, even under favorable meteorological conditions, allowing emissions without restriction is also not advisable because aerosol pollution allowed to accumulate to a certain extent will significantly worsen the BL meteorological conditions and close the “meteorological channels” available for pollution dispersion.

Information regarding dust concentrations and size distributions is very important for determining air quality and aerosol–radiation–cloud interactions. Only by using a correct erosion database can the sectional dust emission scheme resolve detailed size distributions and determine where and how dust will be emitted. In this paper, the bias and reasons for dust emission in China Meteorological Administration Unified Atmospheric Chemistry Environment–Dust, an operational dust forecasting model, are analyzed using a heavy sand and dust storm episode. We used 18 years of routine sand and dust storm phenomena recorded at meteorological stations to retrieve and update the desertification details in the MBA sectional dust emission scheme adopted in China Meteorological Administration Unified Atmospheric Chemistry Environment–Dust. New desertification details include decreased erodibility in the area adjacent to Uzbekistan, Turkmenistan, and southern Kazakhstan, where Kyzylkum, Karakum, and Aralkum are located in central Asia, and in the Chinese deserts of Onqin Daga, Mu Us, and Gurbantungut. New desertification also results in increased erodibility in northern Mongolia. Comparisons show that the new desertification database decreases overestimation of dust emission in central Asia, including western Mongolia. It improves the underestimation of dust emission in northern Mongolia and the Gobi desert in southeast Mongolia, and the Taklimakan desert in China. Consequently, it corrects the overestimated dust cloud in the source area and in areas impacted by dust transportation. The timing, quantitative mass concentrations, and dust size distributions determined here are all more reasonable and rational than those of the original case. Dust emission in a heavy sand and dust storm (SDS) is overestimated in central Asia and underestimated in Mongolia by the sectional SDS model CUACE/DustDesertification classification was improved using SDS data from meteorological stations and incorporating local land use changesOverestimations and underestimations of dust emissions/concentrations by CUACE/Dust were corrected using new desertification information

Among RNA 5′-cap structures, γ-phosphate monomethylation is unique to a small subset of noncoding RNAs, 7SK and U6 in humans. 7SK is capped by methylphosphate capping enzyme (MePCE), which has a second nonenzymatic role as a core component of the 7SK ribonuclear protein (RNP), an essential regulator of RNA transcription. We report 2.0- and 2.1-Å X-ray crystal structures of the human MePCE methyltransferase domain bound to S-adenosylhomocysteine (SAH) and uncapped or capped 7SK substrates, respectively. 7SK recognition is achieved by protein contacts to a 5′-hairpin-single-stranded RNA region, thus explaining MePCE’s specificity for 7SK and U6. The structures reveal SAH and product RNA in a near-transition-state geometry. Unexpectedly, binding experiments showed that MePCE has higher affinity for capped versus uncapped 7SK, and kinetic data support a model of slow product release. This work reveals the molecular mechanism of methyl transfer and 7SK retention by MePCE for subsequent assembly of 7SK RNP.

This study compares the aerosol optical properties measured by CE318 sunphotometers at the Institute of Atmospheric Physics and the Chinese Academy of Meteorological Sciences in Beijing between January 2013 and July 2015 to provide the framework to quantify the spatial and temporal variability of aerosol properties. Aerosol optical parameters included extinction (scattering plus absorption) aerosol optical depth (EAOD), extinction Ångström exponent (EAE), columnar water vapor (CWV), absorption aerosol optical depth (AAOD), absorption Ångström exponent (AAE), extinction aerosol optical depth of fine particles (EAODf), extinction aerosol optical depth of coarse particles (EAODc), real parts of the refractive index (REFR), imaginary parts of the refractive index (REFI), single scattering albedo (SSA), asymmetry factor (ASYM), size distribution, and sphericity fraction. Comparison of aerosol optical properties using the simultaneous observations between two sites showed that correlation coefficients were larger than or equal to 0.98 for EAOD, EAE, and CWV, but smaller than or equal to 0.90 for AAOD, REFR, REFI, and SSA; the percentage differences for most of the parameters were less than 2%, but for EAODfwere relatively large, ranging from 4.35 to 6.45%; the mean size distributions simultaneously showed bi-modal patterns, with two peak volumes at the radii of 0.15 and 2.94 μm; two kinds of tri-peak model were apparent during the study period; a case of EAODs at 440 nm differing by more than 0.2 between the two sites reflected the effect of local aerosol pollution. Comparison of aerosol characterization inferred by absorption properties using all the inversion data showed that classification using EAE, AAE, and sphericity fraction indicated the main aerosol type was “U/I&BB” (urban/industrial and biomass-burning), accounting for 59.87 and 57.43%, respectively; the volume size distribution retrievals binned by AAE exhibited coarse mode particles became dominant as AAE increased to 2.0; the SSA retrievals binned by AAE demonstrated SSA transitioned from spectra representing dust to U/I&BB pollution; averaged SSA for all the retrievals and SSA data partitioned by the EAE and η675 nmsuggested there were more absorbing aerosols at IAP. The results of the study will be beneficial in validating satellite observations and model simulation results, providing more accurate input parameters for model simulations.

Explaining the evolution of cooperation remains one of the greatest problems for both biology and social science. The classical theories of cooperation suggest that cooperation equilibrium or evolutionary stable strategy between partners can be maintained through genetic similarity or reciprocity relatedness. These classical theories are based on an assumption that partners interact symmetrically with equal payoffs in a game of cooperation interaction. However, the payoff between partners is usually not equal and therefore they often interact asymmetrically in real cooperative systems. With the Hawk-Dove model, we find that the probability of cooperation between cooperative partners will depend closely on the payoff ratio. The higher the payoff ratio between recipients and cooperative actors, the greater will be the probability of cooperation interaction between involved partners. The greatest probability of conflict between cooperative partners will occur when the payoff between partners is equal. The results show that this asymmetric relationship is one of the key dynamics of the evolution of cooperation, and that pure cooperation strategy (i.e., Nash equilibrium) does not exist in asymmetrical cooperation systems, which well explains the direct conflict observed in almost all of the well documented cooperation systems. The model developed here shows that the cost-to-benefit ratio of cooperation is also negatively correlated with the probability of cooperation interaction. A smaller cost-to-benefit ratio of cooperation might be created by the limited dispersal ability or exit cost of the partners involved, and it will make the punishment of the non-cooperative individuals by the recipient more credible, and therefore make it more possible to maintain stable cooperation interaction.

Mechanochromic structural-colored materials have promising applications in various domains. In this Letter, we report three types of reversible mechanochromisms in simple material systems by harnessing mechano-responsive wrinkling dynamics including (i) brightness mechanochromism (BM), (ii) hue change mechanochromism (HCM), and (iii) viewable angle mechanochromism (VAM). Upon stretching, the BM device exhibits almost a constant hue but reduces light brightness due to the postbuckling mechanics-controlled deformation, while the HCM device can change the hue from blue to red with almost constant intensity because of the linear elastic mechanics-controlled deformation. The VAM device shows a constant hue because of the thin film interference effect. However, the viewable angles decrease with increasing applied strain owing to the light scattering of wrinkles. All of the mechanochromic behaviors exhibit good reversibility and durability. We clearly elucidated the underlying mechanisms for different mechanochromisms and demonstrated their potential applications in smart displays, stretchable strain sensors, and antipeeping/anticounterfeiting devices.

Based on 481-year records of historical dust storm (DS) and Dryness-Wetness Index (DWI) at 120 sites, spatial distribution characteristics of dryness-wetness (DW) in typical dust storm years (DS years) and in non-dust storm years (non-DS years) were derived for continental China. In DS years, most of the sites were drier than in normal years while in non-DS years wetter than normal, and the variation of DWI in DS years was larger than that in non-DS years. The relative instability and increased regional difference of atmospheric circulation in DS years might have induced more frequent DS events and dry-wet abnormality in continental China. In DS years the latitudinal (north-south) dry-wet difference was larger than that in non-DS years, that is, north China was even much drier than south China. This might be attributed to increased latitudinal differences of thermal and pressure gradients in DS years, resulting in the southward withdrawal of precipitation and increase of DS events.

The objectives of this research were to characterise the clay minerals composition of soil-derived dust in Northern China and to set up a mineralogical signature to trace their origin. Mineral composition of aerosol particles was investigated at Aksu, Dunhuang, Yulin, Tongliao and Changwu during an intensive field campaign period of ACE-Asia. The results show that the kaolinite (K) to chlorite (C) ratio is sensitive to the regional origin of Asian dust. Western source areas (represented by Aksu) displayed the lowest K/C ratio of 0.3 (average), while it was found to increase up to 0.70 (average) upon moving towards northern source areas (represented by Yulin). By studying transported dust in a deposition area representative of the Chinese Loess Plateau, the usefulness of the K/C ratio, when associated with back air-mass trajectories, was found to lie in revealing the origin of the dust. Comparison of the mineralogical data between Asian dust and Sahara dust, shows that the K/C ratio is also an effective signature to identify the source areas on a hemisphere scale.

Retrieving historical fine particulate matter (PM2.5) data is key for evaluating the long-term impacts of PM2.5on the environment, human health and climate change. Satellite-based aerosol optical depth has been used to estimate PM2.5, but estimations have largely been undermined by massive missing values, low sampling frequency and weak predictive capability. Here, using a novel feature engineering approach to incorporate spatial effects from meteorological data, we developed a robust LightGBM model that predicts PM2.5at an unprecedented predictive capacity on hourly (R2 = 0.75), daily (R2 = 0.84), monthly (R2 = 0.88) and annual (R2 = 0.87) timescales. By taking advantage of spatial features, our model can also construct hourly gridded networks of PM2.5. This capability would be further enhanced if meteorological observations from regional stations were incorporated. Our results show that this model has great potential in reconstructing historical PM2.5datasets and real-time gridded networks at high spatial-temporal resolutions. The resulting datasets can be assimilated into models to produce long-term re-analysis that incorporates interactions between aerosols and physical processes.A high-performance machine-learning model incorporating spatial effects was developed to estimate historical PM2.5 concentrations based on meteorological data. Capable of hourly resolution, this dataset will be of great value for understanding PM2.5's long-term climate and environmental effects and producing chemical-weather coupled reanalysis.

In this paper, the question of when the subdirect sum of two doubly strictly diagonally dominant (DSDDs) matrices is addressed. Some sufficient conditions are given, and these sufficient conditions only depend on the elements of the given matrices. Moreover, examples are presented to illustrate the corresponding results.

Recently, biomaterials for cartilage regeneration has been intensively investigated. However, the development of scaffolds that capture regenerated cartilage with biomechanical and structural recovery has rarely been reported. To address this challenge, platelet-rich plasma (PRP)-based cartilage constructs with a well-orchestrated symphony of cellular, biochemical and biomechanical elements were prepared by simultaneously employing chondrogenic progenitor cells (CPCs) as a cell source, optimizing platelet concentration, and adding an enzyme-ion activator. It was shown that this triple-optimized PRP + CPC construct possessed increased biomechanical properties and suitable biochemical signals. The following in vitrostudy demonstrated that the triple-optimized PRP + CPC constructs generated cartilage-like tissue with higher expression levels of chondrogenic-specific markers, more deposition of cartilage-specific extracellular matrix (ECM), and greater biomechanical values than those of the other constructs. Twelve weeks after the construct was implanted in a cartilage defect in vivo, histological analysis, qPCR, and biomechanical tests collectively showed that the triple-optimized constructs yielded a more chondrocyte-like cell phenotype with a higher synthesis of Col-II and aggrecan. More importantly, the triple-optimized constructs facilitated cartilage regeneration with better biomechanical recovery than that of the other constructs. These results demonstrate the efficacy of the triple-optimization strategy and highlight the simplicity and potency of this PRP + CPC construct for cartilage regeneration.

Aerosol microphysical and optical properties as well as aerosol direct radiative effect (ADRE) were measured at a few ground sites to investigate aerosol optical‐radiative characteristics in northeastern China. Bimodal size distributions showed a dominance of fine mode particles at Shenyang, a megacity, and more impacts from larger particles at Fushun and Dalian, industrial and coastal sites, respectively. High aerosol optical depths at 440 nm in July (0.67–1.25) were ascribed to hygroscopic effects or cloud processing. Single scattering albedos at 440 nm show strong to moderate absorption at the urban and industrial sites (0.84–0.86) and weaker absorption at the coastal and rural sites (0.92–0.94). The single scattering albedo wavelength dependence implied influences of dust at the urban, industrial, and coastal regions (shorter wavelengths) and biomass emissions at the rural site (longer wavelengths). Absorptive aerosol optical depths at the urban and industrial sites were ~2.5 and 3.7 times higher than at the coastal and rural sites. Large negative ADREs at the bottom of the atmosphere at the urban and industrial sites implied strong surface cooling and the larger ADREs at the top of the atmosphere at the coastal site indicated more cooling of the Earth‐atmosphere system. The main aerosol types at the urban and industrial sites were mixed absorbing particles, while weakly‐absorbing fine mode particles dominated the coastal and rural sites. This study provides new information on the aerosol distributions and potential regional climate effects of aerosols in northeastern China. High AODs in July were ascribed to hygroscopic effects in Northeast ChinaThe SSA440 nmshow strong to slight absorption over the study regionThere is stronger surface cooling effect at the urban and industrial sites