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Developing low-cost non-precious metals as efficient catalysts for the reduction of toxic 4-nitrophenol (4-NP) to useful 4-aminophenol (4-AP) have received increasing attention in recent years. Herein, a novel and efficient Cu-based catalyst Cu/CuxO@CN (carbon doped with nitrogen) was prepared via a facile method from pyrolysis of bi-ligand MOFs material Cu-2(BDC)(2)(BPY) (BDC = p-Phthalic acid, BPY = 4,40'-b ipyridyl) in Ar atmosphere. Characterization results revealed that N doping in carbon matrix favors the development of mesoporous structure, the formation of more defect sites in carbon matrix, better dispersion of Cu/CuxO nano particles, and maintenance of Cu species in metallic Cu state (the active site), all of which contribute to a superior catalytic activity for 4-NP reduction with a pseudo-first-order rate constant as high as 0.126 s(-1) (the molar ratio of NaBH4 to 4-NP is 400), nearly 11 times higher than its counterpart Cu/CuxO@C without N doping (0.011 s(-1)). The activation energy for 4-NP reduction to 4-AP catalyzed by Cu/CuxO@CN was determined as 55.6 kJ mol(-1) (the molar ratio of NaBH4 to 4-NP is 100). In addition, Cu/CuxO@CN showed excellent reusability in successive 6 cycles. The facile synthesis and superior catalytic activity make Cu/CuxO@CN a promising catalyst in industrial applications for many other similar reaction systems. (C) 2021 Elsevier Inc. All rights reserved.

The reduction of carbon dioxide (CO2 ) into value-added fuels using an electrochemical method has been regarded as a compelling sustainable energy conversion technology. However, high-performance electrocatalysts for CO2 reduction reaction (CO2 RR) with high formate selectivity and good stability need to be improved. Earth-abundant Bi has been demonstrated to be active for CO2 RR to formate. Herein, we fabricated an extremely active and selective bismuth nanosheet (Bi-NSs) assembly via an in situ electrochemical transformation of (BiO)2 CO3 nanostructures. The as-prepared material exhibits high activity and selectivity for CO2 RR to formate, with nearly 94% faradaic efficiency at -1.03 V (versus reversible hydrogen electrode (vs. RHE)) and stable selectivity (>90%) in a large potential window ranging from -0.83 to -1.18 V (vs. RHE) and excellent durability during 12 h continuous electrolysis. In addition, the Bi-NSs based CO2 RR/methanol oxidation reaction (CO2 RR/MOR) electrolytic system for overall CO2 splitting was constructed, evidencing the feasibility of its practical implementation.

The corrosion behaviour of Mg-6Gd-3Y-1Zn-0.3Ag (wt.%) alloy components with different sizes after cooling was investigated. The alloys in the small components (SC) cooled fast, which were composed of α-Mg matrix and coarse long-period stacking ordered (LPSO) phases. The alloys in the large components (LC) cooled slowly, and there were thin lamellar LPSO phases precipitating inside the grains, except for α-Mg matrix and coarse LPSO phases. The hydrogen evolution test revealed that the corrosion rate of LC sample was higher than that of SC sample. Electrochemical impedance spectroscopy (EIS) test showed that the surface film on LC alloys provided worse protection. The corrosion morphologies indicated that the precipitation of the thin lamellar LPSO phases in LC sample caused severe micro-galvanic corrosion, which accelerated the rupture of the surface film.

An electrocatalytic carbon dioxide reduction reaction (CO2RR) is an appealing route to obtain the value-added feedstocks and alleviate the energy crisis. However, how to achieve high-performance electrocatalysts for CO2 reduction to formate is challenging owing to the poor intrinsic activity, insufficient conductivity, and low surface density of active sites. Herein, we fabricated an extremely active and selective hydrangea-like superstructured micro/nanoreactor of ultrathin bismuth nanosheets through an in situ electrochemical topotactic transformation of hierarchical bismuth oxide formate (BiOCOOH). The resulted bismuth nanosheet superstructure is in the form of three-dimensional intercrossed networks of ultrathin nanosheets, forming an ordered open porous structure through self-assembly, which can be used as a micro/nanoreactor to enable a large electrochemically active surface area as well as high atomic utilization. Such a distinctive nanostructure endows the material with high electrocatalytic performances for CO2 reduction to formate with near-unity Faradaic selectivity (>95%) in a wide potential window from -0.78 to -1.18 V. Furthermore, this micro/nanoreactor can give the high current densities over 300 mA cm-2 at low applied potentials without compromising selectivity in a flow cell reactor. Density functional theory (DFT) and in situ attenuated total reflection-infrared spectroscopy (in situ ATR-IR) were further conducted to interpret the CO2RR mechanisms.

Rapid advances in 3D hybrid additive manufacturing have provided opportunities to the use of Ta as a highly effective biomaterial. In this study, we used electron beam melting (EBM) process to fabricate Ti–6Al–4V 3D structures (EBM-Ti64) and then applied cold spray additive manufacturing to deposit commercially pure (CP) Ti, Ti–Ta composite and pure Ta coatings on the EBM-Ti64 substrate to explore the biocompatibility of Ti–Ta composite structures through hybrid additive manufacturing. The microstructure, microhardness, corrosion resistance and biocompatibility were evaluated. Feedstock powders and process parameters of cold spray determine the microstructures of the deposited coating. Microhardness and indentation testing of Ti–Ta composite reveal the weight ratio of Ta influences the microhardness. In particular, higher corrosion resistance was achieved on cold sprayed Ti–30%Ta composite compared to CP Ti and pure Ta coatings. Moreover, live/dead and MTS assay demonstrate that the cold sprayed coatings were non-toxic, while the EBM-Ti64 substrate shows some cytotoxicity signs which might be related to the released toxic ions. This study confirms the biocompatible Ti–Ta composite structures can be manufactured through a combination of EBM and cold spray, opening opportunities for the rapid hybrid manufacture of biocompatible implants.

Currently, most of the hole transport layers (HTLs) of organic solar cells (OSCs) are unable to meet the requirements of printing preparation, which imposes restrictions on the commercial process of the OSCs severely. Here, we report a printable HTL, PCPDTK0.50H0.50-TT. The PM6:Y6:PC71BM device with PCPDTK0.50H0.50-TT as an HTL exhibits a power conversion efficiency (PCE) of 16.3% (with an area of 0.04 cm2). More importantly, the PCE of the device is up to 10.2%, with an area of 1.0 cm2 prepared by the wire-bar coating PCPDTK0.50H0.50-TT HTL, which is in favor of the printing fabrication of the OSCs. In view of the superiorities of the large-area printing and the impressive PCE, we believe that PCPDTK0.50H0.50-TT should be a potential HTL for industrial production of OSCs.

This letter reports a multi-spectral infrared chemical sensor based on a virtual array of bulk acoustic wave resonators with different frequencies. The plasmonic metasurfaces with different patterns on the top surface of resonators provide high IR absorption without degradation of resonating performance. The metasurfaces enhance the frequency responses of the resonant sensor to the specific infrared by about ten times. In a demonstration, four kinds of polymers and their mixtures were detected by the sensor to show its capability for distinguishing unknown compounds. The proposed chemical sensor shows great potential for fast, accurate and portable infrared spectrum microsystems for chemical composition analysis.

A series of novel metal–organic frameworks were synthesized by using semirigid ligand 1,1′,1″-(1,3,5-triazine-2,4,6-triyl)tripiperidine-4-carboxylic acid (H3TTPCA) and lead halide (Cl, Br, or I). T...

Low-Ag Sn-0.7Cu-0.5Ag Pb-free solder solidifies into βSn dendrite and coupled eutectics structures. In this study, a range of solidification events in Sn-0.7Cu-0.5Ag solder alloy, such as primary βSn dendrite growth, binary eutectics and ternary eutectics growth, have been studied using in situ time-resolved synchrotron X-ray radiography. It was found that primary βSn dendrite arms showed accelerated growth, whilst secondary dendrite arms competitive growth/coarsening was strongly influenced by neighboring arms. Axial remelting of tertiary arms of βSn dendrite also occurred during coarsening. Most importantly, simultaneous growth of invariant binary βSn-Ag3Sn eutectic/ternary βSn-Cu6Sn5-Ag3Sn eutectic were observed.

This paper describes the detection and discrimination of volatile organic compounds (VOCs) using an e-nose system based on a multiparameter virtual sensor array (VSA), which consists of a single-chip temperature-compensated film bulk acoustic wave resonator (TC-FBAR) coated with 20-bilayer self-assembled poly(sodium 4-styrenesulfonate)/poly(diallyldimethylammonium chloride) thin films. The high-frequency and microscale FBAR multiparameter VSA was realized by temperature modulation, which can greatly reduce the cost and complexity compared to those of a traditional e-nose system and can allow it to operate at different temperatures. The discrimination effect depends on the synergy of temperature modulation and the sensing material. For proof-of-concept validation purposes, the TC-FBAR was exposed to six different VOC vapors at six different gas partial pressures by real-time VOC static detection and dynamic detection. The resulting frequency shifts and impedance responses were measured at different temperatures and evaluated using principal component analysis and linear discriminant analysis, which revealed that all analytes can be distinguished and classified with more than 97% accuracy. To the best of our knowledge, this report is the first on an FBAR multiparameter VSA based on temperature modulation, and the proposed novel VSA shows great potential as a compact and promising e-nose system integrated in commercial electronic products.

Drift bipolar junction transistors (BJTs), characterized by a graded doping profile in the base region, are susceptible to the recombination in both the base and emitter–base depletion regions when they are damaged by atomic displacement, leading to the gain degradation. The previous model of the gain degradation of BJTs (i.e., Messenger–Spratt model) adopts the assumptions of the neutral base and ideal depletion, which are not valid for the drift BJTs. A drift BJT has an extra build-in electric field which breaks the neutral base condition, and the excess recombination rate is reduced and depends on the drift parameters. Furthermore, the nonideal depletion effects can suppress the excess recombination in the junction region, which will also reduce the susceptibility of the displacement damage (DD). This paper presents a physics-based improvement of the previous model and provides a much better fit to the experimental data of the 3CK3B drift BJTs subjected to deuterium–tritium 14-MeV neutron irradiation. The new model also suggests that the ideal factor of excess base current induced by DD approaches to 1.33 for the BJT technologies with narrow base or operated under low bias conditions.

Effects of La2O3 modification on the microstructure, mechanical and ablation properties of C/C-SiC composites were investigated. Experimental results show that a new La10(SiO4)6O3 phase was generated during heat treatment process. The presence of the La-compounds, namely La2O3 and La10(SiO4)6O3, had an important impact on the structure of reinforced skeleton and the molten oxide film, and thus strongly affected the mechanical and ablation properties of the composites. Excessive La addition induced the structural damage of the reinforced skeleton, resulting in weakened mechanical and ablation properties. The C/C-SiC composites with 25.65 wt.% La2O3 addition displayed better mechanical properties and the best ablation resistance. The La10(SiO4)6O3 phase could react with molten silica to form a viscous glass during ablation. The transformation of La-compounds into La2Si2O7 can reduce the ablation of SiO2 and enhance the glass film, so as to protect the composites from further ablation.

The performance of flexible organic solar cells (OSCs) significantly relies on the quality of transparent flexible electrode. Here, we used silver nanowires (AgNWs) with various weight ratios to dope high-conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PH1000) to optimize the optical and electronic properties of PH1000 film. A high-quality flexible composite electrode PET/Ag-mesh/PH1000:AgNWs-20 with smooth surface, a low sheet resistance of 6 Ω/sq and a high transmittance of 86% at 550-nm wavelength was obtained by doping 20 wt% AgNWs to PH1000 (PH1000:AgNWs-20). The flexible OSCs based on the PET/Ag-mesh/PH1000:AgNWs-20 electrode delivered a power conversion efficiency (PCE) of 12.07% with an open circuit voltage ( V oc) of 0.826 V, a short-circuit current density ( J sc) of 20.90 mA/cm2 and a fill factor (FF) of 69.87%, which is the highest reported PCE for the flexible indium-tin oxide (ITO)-free OSCs. This work demonstrated that the flexible composite electrodes of PET/Ag-mesh/PH1000:AgNWs are promising alternatives for the conventional PET/ITO electrode, and open a new avenue for developing high-performance flexible transparent electrode for optoelectronic devices.

The main components of global carbon budget calculations are the emissions from burning fossil fuels, cement production, and net land-use change, partly balanced by ocean CO2 uptake and CO2 increase in the atmosphere. The difference between these terms is referred to as the residual sink, assumed to correspond to increasing carbon storage in the terrestrial biosphere through physiological plant responses to changing conditions (ΔBphys). It is often used to constrain carbon exchange in global earth-system models. More broadly, it guides expectations of autonomous changes in global carbon stocks in response to climatic changes, including increasing CO2, that may add to, or subtract from, anthropogenic CO2 emissions. However, a budget with only these terms omits some important additional fluxes that are needed to correctly infer ΔBphys. They are cement carbonation and fluxes into increasing pools of plastic, bitumen, harvested-wood products, and landfill deposition after disposal of these products, and carbon fluxes to the oceans via wind erosion and non-CO2 fluxes of the intermediate breakdown products of methane and other volatile organic compounds. While the global budget includes river transport of dissolved inorganic carbon, it omits river transport of dissolved and particulate organic carbon, and the deposition of carbon in inland water bodies. Each one of these terms is relatively small, but together they can constitute important additional fluxes that would significantly reduce the size of the inferred ΔBphys. We estimate here that inclusion of these fluxes would reduce ΔBphys from the currently reported 3.6 GtC yr−1 down to about 2.1 GtC yr−1 (excluding losses from land-use change). The implicit reduction in the size of ΔBphys has important implications for the inferred magnitude of current-day biospheric net carbon uptake and the consequent potential of future biospheric feedbacks to amplify or negate net anthropogenic CO2 emissions.

Four coordination polymers (CPs), [Zn2(H2BCA)2(o-bimb)2(H2O)2]n (1), {[Pb(H2BCA)(p-bib)0.5]·H2O}n (2), {[Cd2(H2BCA)2(p-bib)2]·(H2O)3}n (3) and {[Zn(H2BCA)(m-bib)]·H2O}n (4), have been derived from the designed flexible bis(4-carboxybenzyl)amine (H2BCA) with bis(imidazole) linkers (p-bib = 1,1′-benzene-1,4-diylbis(1H-imidazole), m-bib = 1,3-bis(1-imidazoly)benzene, and o-bimb = 1,2-bis(imidazol-1-ylmethyl) benzene). X-ray single crystal diffraction analyses reveal that complex 1 is a 3D supramolecular structure composed of 2D 3-connected hcb layers via hydrogen contacts. Complex 2 exhibits a 3D 2-nodal (4,5)-connected {44.62}{44.66}-tcs net. Complex 3 shows a novel 2-nodal 3D (4,5,5)-connected net with the point symbol {4.66.83}2{42.62.82}. Complex 4 displays a 3D 3-fold interpenetrating 3-connected {103} ThSi2 net. Structural comparison reveals that the central ions as well as the auxiliary ligand play critical roles in determining the coordination modes of H2BCA and the final structures. In addition, the luminescence measurements of two zinc-containing compounds (1 and 4) have been discussed and show excellent selectivity and sensitivity in detecting acetone molecules and Cr2O72−/CrO42− anions in aqueous solution.

The power conversion efficiencies (PCEs) of nonfullerene organic solar cells (OSCs) have made significant progress. However, little attention has been paid to improving the thermal stability of nonfullerene OSCs, which is critical for future practical application. Herein, two novel isomeric nonfullerene small molecule acceptors (n-SMAs) based on the classical ITIC acceptors, namely oF-ITIC and mF-ITIC, with fluorine atoms substituting at the ortho-alkyl and meta-alkyl positions of the phenyl side chains, respectively, are designed. The effect of fluorinated side-chains on the efficiency and thermal stability is systematically investigated. When combined with PBTIBDTT, both oF-ITIC and mF-ITIC devices show enhanced PCEs as compared to the ITIC device. More importantly, these active layers show distinct degrees of morphological deterioration under thermal annealing. Among the acceptors, mF-ITIC shows the best thermal stability, retaining 92% of its initial device efficiency after thermal annealing for 96 h at 150 °C, while ITIC and oF-ITIC devices only preserve 82% and 67% of their initial efficiencies, respectively. Investigation indicates that the miscibility of donor/acceptor and crystallinity of the acceptors synergistically affect the thermal stability of the active layers, which provides a new molecule design strategy to achieve high efficiency nonfullerene OSCs with outstanding thermal stability.

Juandan-Baihe (Lilium lancifolium Thunb.), Lanzhou-Baihe (Lilium davidii var. unicolor), and Jin-Baihe (Lilium trompeten) are of the same family, but of different genera. They have often been used in Chinese Materia Medica (CMM) as Lilii Bulbus in the Chinese market. These three species of CMM are often confused, and thus, for better application, they must be accurately identified. Herein we use a headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) technique as a screening system to authenticate the three species of CMM. The obtained ion mobility data were processed using LAV processing software to identify fingerprints and perform principal component analysis (PCA). From the fingerprints, fifty peaks, for 36 compounds, were identified, among which 3-methylbutanal was the most abundant in Lilium lancifolium Thunb. (JD), butanone was the most abundant in Lilium davidii var. unicolor (LZ), and 3-methylbutanoic acid and 2-heptanone were the most abundant in Lilium trompeten (WP). All three species have a characteristic area in the fingerprint containing their characteristic biomarker. The PCA for the initial solution to original variables showed that the two principal components accounted for 53% and 21% of the total variance. This research is aimed at establishing a green, rapid method based on HS-GC-IMS to provide scientific data for discrimination between Lilii Bulbus from different species.

The evacuation process from a supermarket under good and limited visibility is investigated by a group of experiments and questionnaires. The evacuations in both situations are compared to explore their differences. Some typical behaviors such as following behavior, helping behavior and finding the dependent during evacuation under limited visibility are observed from the experimental video. The reduced visibility hinders pedestrian movement and prolongs evacuation process. As a result, pedestrians need more time to evacuate from the supermarket under limited visibility. However, a similar point is that pedestrians prefer to select the closest exit and minimize their movement distances in both situations. A multi-grid model considering these typical behaviors is proposed to simulate pedestrian evacuation under both conditions and simulation results agree well with the experiment results. Finally simulations with and without obstacles inside are compared to study the effect of obstacles on evacuation time. The study is helpful to understand pedestrian behavior and develop efficient evacuation strategy to guide pedestrian evacuation under limited visibility.

Epoxidation of bio-derived plant oils is a sustainable route to manufacturing plasticizers, additives in lubricants, and other chemicals. The traditional synthetic approaches suffer from the employment of corrosive mineral acid or expensive peroxides (e.g., H2O2). In this work, we report the epoxidation of plant oils using O2 as the terminal oxidant catalyzed by Co-N-C/SiO2 single-atom catalyst. The single-atom dispersion of cobalt is confirmed by high-angle annular dark field-STEM and x-ray absorption fine structure techniques. In the epoxidation of methyl oleate under mild reaction conditions (35 °C, 0.1 MPa O2), 99% selectivity to the desired product is achieved at full conversion. Even for crude oils, Co-N-C/SiO2 is also effective and good yields of the corresponding epoxides are obtained. In addition, the catalyst is easily recovered and can be reused five times without obvious decay in catalytic activity/selectivity. A superoxide radical involved reaction mechanism is proposed on the basis of kinetic study and EPR experiment.

Studying solar filaments can help in understanding the distribution of large-scale field in the solar atmosphere and provide useful insights into the nature of the solar magnetic field. Recently, the National Astronomical Observatory of the Chinese Academy of Sciences has collected huge volumes of data about solar filaments from several international observing stations for nearly 100 years. Designing a database, as well as establishing a networked tool for making the best of it, are necessary to provide efficient and convenient access to the data for researchers. In this study, we introduce a solar filament database, involving digital image data of nearly 45 terabytes, based on MySQL and a data management platform named database management system of hundred years of solar filament archives ( http://faste.ctgu.edu.cn ) that adopts Browser/Server mode and is written in the Java programming language. From this data system, users can realise multi-property query on the basis of demands, download data under multiple conditions, perform visual query for information on one single filament, view long-term data statistics of filament properties, and implement extensions and management of the database.

Cointegration and coupling a perfect metamaterial absorber (PMA) together with a film bulk acoustic wave resonator (FBAR) in a monolithic fashion is introduced for the purpose of producing ultracompact uncooled infrared sensors of high sensitivity. An optimized ultrathin multilayer stack was implemented to realize the proposed device. It is experimentally demonstrated that the resonance frequency of the FBAR can be used efficiently as a sensor output as it downshifts linearly with the intensity of the incident infrared irradiation. The resulting sensor also achieves a high absorption of 88% for an infrared spectrum centered at a wavelength of 8.2 μm. The structure is compact and can be easily integrated on a CMOS-compatible chip since both the FBAR and PMA utilize and share the same stack of metal and dielectric layers.

For the scattering problems of acoustic wave for an open arc in two dimensions, we give a uniqueness and existence analysis via the single layer potential approach leading to a system of integral equations that contains a weakly singular operator. For its numerical solutions, we describe an $O(h^{3})$ O ( h 3 ) order quadrature method based on the specific integral formula including convergence and stability analysis. Moreover, the asymptotic expansion of errors with odd power $O(h^{3})$ O ( h 3 ) is got and the Richardson extrapolation algorithm (EA) is used to improve the accuracy of numerical solutions. The efficiency of the method is illustrated by a numerical example.

The bug Orius similis Zheng is a native generalist predator of insect pests in southern China. The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), is a notorious defoliator that is now an economically important insect pest throughout China. To investigate the ability of O. similis to control FAW, we evaluated the predatory capacity, behavior, and functional response of O. similis with respect to FAW and their olfactory response. Both females and males successfully preyed on FAW eggs and first-instar larvae but not on second-instar or older larvae. Adult O. similis only attacked and killed one egg or one larva at a time before sucking the prey, and similar predatory behavior was also observed with regard to FAW egg masses. Both female and male O. similis exhibited type II functional response when preying on FAW eggs and first-instar larvae. Maximum estimated prey consumed per day was 23.7 eggs and 26.2 larvae for adult females and 22.5 eggs and 19.6 larvae for adult males. Moreover, in a Y-tube olfactometer experiment, both female and male O. similis exhibited a significant preference for maize (Zea mays L.) seedlings damaged by FAW over clean air, healthy seedlings, FAW feces, and FAW, suggesting that seedlings damaged by FAW may releases specific volatiles attracting the predator. Collectively, the results of the study suggest that O. similis is a promising candidate for the biological control of FAW eggs and first-instar larvae, particularly given its attraction to FAW-damaged leaves, which may enable it to locate the target prey rapidly.

Magnesium alloys are commonly melted and held in steel or cast iron crucibles and small but important amounts of Fe and C can dissolve into Mg-rich melts. Here, carbide formation is studied during interface reactions between solid Fe-xC alloys (x = 0–3.6 wt%) and liquid Mg-9Al-0.7Zn-0.2Mn (wt.%, AZ91) at temperatures from 700 to 800 °C. Two ternary carbides, AlFe3C and Al2MgC2, formed in the reaction layers between the Fe-C and AZ91, and T2-Al2MgC2 additionally formed within the AZ91 alloy due to carbon pickup. T2-Al2MgC2 grew in liquid AZ91 as hexagonal plates that were commonly twinned. A reproducible orientation relationship was measured between T2-Al2MgC2 and α-Mg, and the grain refinement of magnesium by heterogeneous nucleation on T2-Al2MgC2 is explored.

Stratospheric ozone and water vapour are key components of the Earth system, and past and future changes to both have important impacts on global and regional climate. Here we evaluate long-term changes in these species from the pre- industrial (1850) to the end of the 21st century in CMIP6 models under a range of future emissions scenarios. There is good agreement between the CMIP multi-model mean and observations, although there is substantial variation between the individual CMIP6 models. For the CMIP6 multi-model mean, global total column ozone (TCO) has increased from ∼300 DU in 1850 to ∼305 DU in 1960, before rapidly declining in the 1970s and 1980s following the use and emission of halogenated ozone depleting substances (ODSs). TCO is projected to return to 1960s values by the middle of the 21st century under the SSP2-4.5, SSP3-7.0, SSP4-3.4, SSP4-6.0 and SSP5-8.5 scenarios, and under the SSP3-7.0 and SSP5-8.5 scenarios TCO values are projected to be ∼10 DU higher than the 1960s values by 2100. However, under the SSP1-1.9 and SSP1-1.6 scenarios, TCO is not projected to return to the 1960s values despite reductions in halogenated ODSs due to decreases in tropospheric ozone mixing ratios. This global pattern is similar to regional patterns, except in the tropics where TCO under most scenarios is not projected to return to 1960s values, either through reductions in tropospheric ozone under SSP1-1.9 and SSP1-2.6, or through reductions in lower stratospheric ozone resulting from an acceleration of the Brewer-Dobson Circulation under other SSPs. CMIP6 multi-model mean stratospheric water vapour mixing ratios in the tropical lower stratosphere have increased by ∼0.5 ppmv from the pre-industrial to the present day and are projected to increase further by the end of the 21st century. The largest increases (∼2 ppmv) are simulated under the future scenarios with the highest assumed forcing pathway (e.g. SSP5-8.5). Both TCO and tropical lower stratospheric water vapour show large variability following explosive volcanic eruptions.

Filaments are very common physical phenomena on the Sun and are often taken as important proxies of solar magnetic activities. The study of filaments has become a hot topic in the space weather research. For a more comprehensive understanding of filaments, especially for an understanding of solar activities of multiple solar cycles, it is necessary to perform a combined multifeature analysis by constructing a data set of multiple solar cycle data. To achieve this goal, we constructed a centennial data set that covers the H$\alpha$ data from five observatories around the world. During the data set construction, we encountered varieties of problems, such as data fusion, accurate determination of the solar edge, classifying data by quality, dynamic threshold, and so on, which arose mainly due to multiple sources and a large time span of data. But fortunately, these problems were well solved. The data set includes seven types of data products and eight types of feature parameters with which we can implement the functions of data searching and statistical analyses. It has the characteristics of better continuity and highly complementary to space observation data, especially in the wavelengths not covered by space observations, and covers many solar cycles (including more than 60 yr of high-cadence data). We expect that this new comprehensive data set as well as the tools will help researchers to significantly speed up their search for features or events of interest, for either statistical or case study purposes, and possibly help them get a better and more comprehensive understanding of solar filament mechanisms., Comment: 20 pages, 17 figures, 1 table, accepted for publication in ApJS

One of the key questions in the air quality and climate sciences is how tropospheric ozone concentrations will change in the future. This will depend on two factors: changes in stratosphere-to-troposphere transport (STT) and changes in tropospheric chemistry. Here we aim to identify robust changes in STT using simulations from the Chemistry Climate Model Initiative (CCMI) under a common climate change scenario (RCP6.0). We use two idealized stratospheric tracers to isolate changes in transport: stratospheric ozone (O3S), which is exactly like ozone but has no chemical sources in the troposphere, and st80, a passive tracer with fixed volume mixing ratio in the stratosphere. We find a robust increase in the tropospheric columns of these two tracers across the models. In particular, stratospheric ozone in the troposphere is projected to increase 10 %–16 % by the end of the 21st century in the RCP6.0 scenario. Future STT is enhanced in the subtropics due to the strengthening of the shallow branch of the Brewer–Dobson circulation (BDC) in the lower stratosphere and of the upper part of the Hadley cell in the upper troposphere. The acceleration of the deep branch of the BDC in the Northern Hemisphere (NH) and changes in eddy transport contribute to increased STT at high latitudes. These STT trends are caused by greenhouse gas (GHG) increases, while phasing out of ozone-depleting substances (ODS) does not lead to robust transport changes. Nevertheless, the decline of ODS increases the reservoir of ozone in the lower stratosphere, which results in enhanced STT of O3S at middle and high latitudes. A higher emission scenario (RCP8.5) produces stronger STT trends, with increases in tropospheric column O3S more than 3 times larger than those in the RCP6.0 scenario by the end of the 21st century.

Electrochemical reduction of CO

Ga alloys have been attracting significant renewed attention for low-temperature bonding applications in electronic packaging. This study systematically investigates the interfacial reaction between liquid Ga and Cu-10Ni substrates at 30 °C. In addition to CuGa2 formed from binary Ga/Cu couples, a layer of nanocrystalline Ga5Ni and CuGa2 formed between the Cu-10Ni substrate and the blocklike micrometer scale CuGa2 layer. The growth of interfacial intermetallics (IMCs) on the Cu-10Ni substrate was substantially accelerated compared to the IMC growth in binary Ga/Cu couples. Reaction kinetics study shows the IMC growth from the Cu-10Ni substrate was controlled by reaction and volume diffusion, while the IMC growth from the Cu substrate was controlled by volume diffusion. It is also found that the presence of Ni within the CuGa2 phase resulted in improved thermal stability and a smaller coefficient of thermal expansion during heating from 25 to 300 °C, using synchrotron XRD analysis. There was least thermal expansion anisotropy among most of the IMCs that form in conventional Sn-based solder alloys, including Cu6Sn5 and so forth. It is concluded that using a Cu-10Ni substrate as opposed to a Cu substrate could achieve sufficient metallurgical bonding within shorter processing time. The results have implications for broadening the application temperatures when using Ga as a low-temperature joining material.

Manganese-bearing intermetallic compounds (IMCs) are important for limiting micro-galvanic corrosion of magnesium-aluminum alloys and can initiate cracks under tensile load. Here, we use electron backscatter diffraction (EBSD), deep etching, and focussed ion beam (FIB) tomography to investigate the types of Al-Mn phases present, their faceted growth crystallography, and their three-dimensional distribution at different locations in high-pressure die cast (HPDC) AZ91D. The Al-Mn particle size distributions were well-described by lognormal distributions but with an additional population of externally solidified crystals (ESCs) formed in the shot chamber analogous to α-Mg ESCs. The large Al8Mn5 particles were cyclic twinned. Differences in the particle size distributions and number density in the center compared with the HPDC skin are identified, and the spatial relationship between Mg17Al12 and Al-Mn particles is explored.

Quantifying forcings from anthropogenic perturbations to the Earth System (ES) is important for understanding changes in climate since the pre-industrial period. In this paper, we quantify and analyse a wide range of present-day (PD) anthropogenic climate forcings with the UK's Earth System Model (ESM), UKESM1, following the protocols defined by the Radiative Forcing Model Intercomparison Project (RFMIP) and the Aerosol and Chemistry Model Intercomparison Project (AerChemMIP). In particular, by quantifying effective radiative forcings (ERFs) that include rapid adjustments within a full ESM, it enables the role of various climate-chemistry-aerosol-cloud feedbacks to be quantified. Global mean ERFs are 1.83, 0.13, −0.33, and 0.93 W m−2 at the PD (Year 2014) relative to the pre-industrial (PI; Year 1850) for carbon dioxide, nitrous oxide, ozone-depleting substances, and methane, respectively. The PD total greenhouse gas ERF is 2.89 W m−2, larger than the sum of the individual GHG ERFs. UKESM1 has an aerosol forcing of −1.13 W m−2. A relatively strong negative forcing from aerosol-cloud interactions and a small negative instantaneous forcing from aerosol-radiation interactions are partially offset by a substantial forcing from black carbon absorption. Internal mixing and chemical interactions mean that neither the forcing from aerosol-radiation interactions nor aerosol-cloud interactions are linear, making the total aerosol ERF less than the sum of the individual speciated aerosol ERFs. Tropospheric ozone precursors, in addition to exerting a positive forcing due to ozone, lead to oxidant changes which in turn cause an indirect aerosol ERF, altering the sign of the net ERF from nitrogen oxide emissions. Together, aerosol and tropospheric ozone precursors (near-term climate forcers, NTCFs) exert a global mean ERF of −1.12 W m−2, mainly due to changes in the cloud radiative effect. There is also a negative PD ERF from land use (−0.32 W m−2). It is outside the range of previous estimates, and is most likely due to too strong an albedo response. In combination, the net anthropogenic ERF is potentially biased low (1.61 W m−2) relative to other estimates, due to the inclusion of non-linear feedbacks and ES interactions. By including feedbacks between greenhouse gases, stratospheric and tropospheric ozone, aerosols, and clouds, some of which act non-linearly, this work demonstrates the importance of ES interactions when quantifying climate forcing. It also suggests that rapid adjustments need to include chemical as well as physical adjustments to fully account for complex ES interactions.

In this paper, we derive the convergence for the high-accuracy algorithm in solving the Dirichlet problem of the modified Helmholtz equation. By the boundary element method, we transform the system to be a boundary integral equation. The high-accuracy algorithm using the specific quadrature rule is developed to deal with weakly singular integrals. The convergence of the algorithm is proved based on Anselone’s collective compact theory. Moreover, an asymptotic error expansion shows that the algorithm is of order Oh03. The numerical examples support the theoretical analysis.

We assess the effective radiative forcing due to ozone-depleting substances using models participating in the Aerosols and Chemistry Model Intercomparison Project (AerChemMIP). A large inter-model ...

Our understanding of the processes that control the burden and budget of tropospheric ozone has changed dramatically over the last 60 years. Models are the key tools used to understand these changes, and these underscore that there are many processes important in controlling the tropospheric ozone budget. In this critical review, we assess our evolving understanding of these processes, both physical and chemical. We review model simulations from the International Global Atmospheric Chemistry Atmospheric Chemistry and Climate Model Intercomparison Project and Chemistry Climate Modelling Initiative to assess the changes in the tropospheric ozone burden and its budget from 1850 to 2010. Analysis of these data indicates that there has been significant growth in the ozone burden from 1850 to 2000 (approximately 43 ± 9%) but smaller growth between 1960 and 2000 (approximately 16 ± 10%) and that the models simulate burdens of ozone well within recent satellite estimates. The Chemistry Climate Modelling Initiative model ozone budgets indicate that the net chemical production of ozone in the troposphere plateaued in the 1990s and has not changed since then inspite of increases in the burden. There has been a shift in net ozone production in the troposphere being greatest in the northern mid and high latitudes to the northern tropics, driven by the regional evolution of precursor emissions. An analysis of the evolution of tropospheric ozone through the 21st century, as simulated by Climate Model Intercomparison Project Phase 5 models, reveals a large source of uncertainty associated with models themselves (i.e., in the way that they simulate the chemical and physical processes that control tropospheric ozone). This structural uncertainty is greatest in the near term (two to three decades), but emissions scenarios dominate uncertainty in the longer term (2050–2100) evolution of tropospheric ozone. This intrinsic model uncertainty prevents robust predictions of near-term changes in the tropospheric ozone burden, and we review how progress can be made to reduce this limitation.

Based on the designed conjugated ligand of N,N'-dioxide 3,3'-benzo(c)cinnoline dicarboxylic acid (H2DBCD) with the aid of d10-metal cations and two ancillary bis(imidazole) bridges, two 3D coordination polymers， namely, {[Cd(DBCD)(1,3-bib)]·(H2O)2}n (1), {[Zn(DBCD)(1,4-bib)]·(H2O)2}n (2), were constructed here. Structural analyses show compounds 1 and 2 are 3-fold and 6-fold interpenetrating dia nets, respectively. Further luminscence studies suggested that the two CPs can selectively and sensitively detect Fe3+ cation in aqueous solution and nitrobenzene derivatives nitrobenzene (NB), p-nitrotoluene (PNT), p-nitroaniline (PNA) and p-nitrophenol (PNP) in DMF.

The influence of Ni on the size and twinning of primary Cu6Sn5 crystals in Sn-0.7Cu-0.05Ni and Sn-xCu (x = 0.7, 0.9, 1.1) (mass%) solder joints is studied using synchrotron radiography and SEM-based EBSD. It is shown that the Ni addition does not cause significant refinement of primary Cu6Sn5 if the alloy is fully melted. However, for peak temperatures ≤250 °C relevant to industrial soldering, primary Cu6Sn5 are not completely melted in Sn-0.7Cu-0.05Ni and there are 10–100 times more numerous and smaller crystals than in Sn-0.7Cu. X-shaped Cu6Sn5 crystals with an angle of ∼70° commonly formed in Sn-0.7Cu-0.05Ni/Cu joints and are shown to be penetration twins. This type of growth twinning was only found in partially melted samples, both in Sn-0.7Cu-0.05Ni/Cu joints and binary Sn-1.1Cu alloy. The frequency of twinned crystals was significantly higher in Ni-containing solders. The results are discussed in terms of the influence of Ni on the Cu6Sn5 liquidus slope and on the lattice parameters of (Cu,Ni)6Sn5.

Herein, one novel coordination polymer [Zn(Htda)(bib)0.5]n (1) based on 5′-carboxyl-[1,1′,3′,1″-terphenyl]-4,4″-dicarboxylic acid (H3tda) and 1,4-bis(1-imidazolyl)benzene (bib) has been achieved. Single-crystal X-ray diffraction analysis reveals that compound 1 crystallizes in the monoclinic system with space group P21/n. The whole structure can be viewed as a 3D 2-nodal (3, 4)-connected net with the Point Symbol of {4.82.103}{4.82}. To our delight, the fluorescence measurement shows that compound 1 can selectively and sensitively detect Cr3+ cations among twelve kinds of metal ions

Power cycling test is often used for the development of lifetime models of power semiconductor devices. The performance of power semiconductor devices in power cycling test is defined by the number of cycles to failure under certain given test conditions. In this work, power cycling tests with the same start test condition but different control strategies were performed. Except the standard control strategy, two other control strategies were realized by regulating three different adjustable parameters. It is also found that the definition of failure criteria in power cycling test will strongly influence the test results, which should also be defined appropriately.

The power conversion efficiencies (PCEs) of flexible organic solar cells (OSCs) still lag behind those of rigid devices and their mechanical stability is unable to meet the needs of flexible electronics at present due to the lack of a high-performance flexible transparent electrode (FTE). Here, a so-called "welding" concept is proposed to design an FTE with tight binding of the upper electrode and the underlying substrate. The upper electrode consisting of solution-processed Al-doped ZnO (AZO) and silver nanowire (AgNW) network is well welded by utilizing the capillary force effect and secondary growth of AZO, leading to a reduction of the AgNWs junction site resistance. Meanwhile, the poly(ethylene terephthalate) is modified by embedding the AgNWs, which are then used to link with the AgNWs in the upper hybrid electrode, thus enhancing the adhesion of the electrode to the substrate. By this welding strategy, critical bottleneck issues relating to the FTEs in terms of optoelectronic and mechanical properties are comprehensively addressed. The single-junction flexible OSCs based on this welded FTE show a high performance, achieving a record high PCE of 15.21%. In addition, the PCEs of the flexible OSCs are less influenced by the device area and display robust bending durability even under extreme test conditions.

We document the development of the first version of the United Kingdom Earth System Model UKESM1. The model represents a major advance on its predecessor HadGEM2‐ES, with enhancements to all component models and new feedback mechanisms. These include: a new core physical model with a well‐resolved stratosphere; terrestrial biogeochemistry with coupled carbon and nitrogen cycles and enhanced land management; tropospheric‐stratospheric chemistry allowing the holistic simulation of radiative forcing from ozone, methane and nitrous oxide; two‐moment, five‐species, modal aerosol; and ocean biogeochemistry with two‐way coupling to the carbon cycle and atmospheric aerosols. The complexity of coupling between the ocean, land and atmosphere physical climate and biogeochemical cycles in UKESM1 is unprecedented for an Earth system model. We describe in detail the process by which the coupled model was developed and tuned to achieve acceptable performance in key physical and Earth system quantities, and discuss the challenges involved in mitigating biases in a model with complex connections between its components. Overall the model performs well, with a stable pre‐industrial state, and good agreement with observations in the latter period of its historical simulations. However, global mean surface temperature exhibits stronger‐than‐observed cooling from 1950 to 1970, followed by rapid warming from 1980 to 2014. Metrics from idealised simulations show a high climate sensitivity relative to previous generations of models: equilibrium climate sensitivity (ECS) is 5.4 K, transient climate response (TCR) ranges from 2.68 K to 2.85 K, and transient climate response to cumulative emissions (TCRE) is 2.49 K/TtC to 2.66 K/TtC.

Recent theoretical studies revealed that two-dimensional (2D) antimonene has attractive characteristics, such as superior photothermal conductivity, absorption over a wide range, high mobility, and good spintronic properties. Herein, we report a reliable liquid phase exfoliation (LPE) route for the preparation of high-quality high-stability atomically thin (AT) antimonene via high ultrasonic power. The AT antimonene delivers a high specific capacity of up to 860 mA·h·g–1, with high rate capability and good cycling stability as an anode of a sodium ion battery (SIB). The good conductivity and 2D structure endow AT antimonene with more active sites for sodium storage, a facilitated pathway for electron transfer and mass transport, and the capability to reduce the volume expansion during the discharge–charge process.

It is important to study pedestrian stepping behavior and characteristics for facility design and pedestrian flow study due to pedestrians’ bipedal movement. In this paper, data of steps are extracted based on trajectories of pedestrians from a single-file experiment. It is found that step length and step frequency will decrease 75% and 33%, respectively, when global density increases from 0.46 ped/m to 2.28 ped/m. With the increment of headway, they will first increase and then remain constant when the headway is beyond 1.16 m and 0.91 m, respectively. Step length and frequency under different headways can be described well by normal distributions. Meanwhile, relationships between step length and frequency under different headways exist. Step frequency decreases with the increment of step length. However, the decrease tendencies depend on headways as a whole. And there are two decrease tendencies: when the headway is between about 0.6 m and 1.0 m, the decrease rate of the step frequency will increase with the increment of step length; while it will decrease when the headway is beyond about 1.0 m and below about 0.6 m. A model is built based on the experiment results. In fundamental diagrams, the results of simulation agree well with those of experiment. The study can be helpful for understanding pedestrian stepping behavior and designing public facilities.

Oxide formation on surface of nitrogen-rich uranium nitride film/particles was investigated using X-ray photoelectron spectroscopy (XPS), auger electron spectroscopy (AES), aberration-corrected transmission electron microscopy (TEM), and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) coupled with electron energy-loss spectroscopy (EELS). XPS and AES studies indicated that the oxidized layer on UN2-x film is ternary compound uranium oxynitride (UNxOy) in 5–10 nm thickness. TEM/HAADF-STEM and EELS studies revealed the UNxOy crystallizes in the FCC CaF2-type structure with the lattice parameter close to the CaF2-type UN2-x matrix. The work can provide further information to the oxidation mechanism of uranium nitride.

The determination of interstitial oxygen atom site in U2N3+xOy film could facilitate the understanding of the oxidation mechanism of α-U2N3 and the effect of U2N3+xOy on anti-oxidation. By comparing the similarities and variances between N K edge and O K edge electron energy loss spectra (EELS) for oxidized α-U2N3 and UO2, the present work looks at the local structure of nitrogen and oxygen atoms in U2N3+xOy film, identifying the most possible position of interstitial O atom.

Micro-diamond modified C/SiC (C/SiC-D) composites were fabricated using pressureless infiltration (PI) and precursor impregnation and pyrolysis (PIP) methods. The influence of micro-diamond addition on the ablation and mechanical properties of C/SiC composites was discussed. Results show that, compared with C/SiC composites, the thermal conductivity of C/SiC-D composites improves 33.7% due to the good thermal properties of diamond particles and the strong connection with SiC matrix. Meanwhile, C/SiC-D composites exhibit significantly enhanced ablation resistance, with the linear ablation rate decreasing by 43.3%, from 0.030 mm s −1 to 0.017 mm s −1 . The introduction of micro-diamond only brings a limited enhancement to the mechanical properties of C/SiC composites due to the small size and low content of the diamond caused by the limitation of PI method.

30 pags., 11 figs., 5 tabs., We quantify the stratospheric injection of brominated very short-lived substances (VSLS) based on aircraft observations acquired in winter 2014 above the Tropical Western Pacific during the CONvective TRansport of Active Species in the Tropics (CONTRAST) and the Airborne Tropical TRopopause EXperiment (ATTREX) campaigns. The overall contribution of VSLS to stratospheric bromine was determined to be 5.0 ± 2.1 ppt, in agreement with the 5 ± 3 ppt estimate provided in the 2014 World Meteorological Organization (WMO) Ozone Assessment report (WMO 2014), but with lower uncertainty. Measurements of organic bromine compounds, including VSLS, were analyzed using CFC-11 as a reference stratospheric tracer. From this analysis, 2.9 ± 0.6 ppt of bromine enters the stratosphere via organic source gas injection of VSLS. This value is two times the mean bromine content of VSLS measured at the tropical tropopause, for regions outside of the Tropical Western Pacific, summarized in WMO 2014. A photochemical box model, constrained to CONTRAST observations, was used to estimate inorganic bromine from measurements of BrO collected by two instruments. The analysis indicates that 2.1 ± 2.1 ppt of bromine enters the stratosphere via inorganic product gas injection. We also examine the representation of brominated VSLS within 14 global models that participated in the Chemistry-Climate Model Initiative. The representation of stratospheric bromine in these models generally lies within the range of our empirical estimate. Models that include explicit representations of VSLS compare better with bromine observations in the lower stratosphere than models that utilize longer-lived chemicals as a surrogate for VSLS., The CONTRAST field deployment was supported by the U.S. NSF, and the ATTREX field deployment was supported by the National Aeronautics and Space Administration (NASA). P. A. W., R. J. S., T. P. C., J. M. N., and D. C. A. received support from NSF, NASA Atmospheric Composition Modeling and Analysis Program (ACMAP), and the NASA Modeling, Analysis, and Prediction (MAP). D. C. A. also received support from the NASA Upper Atmospheric Research Program. J. M. N. was also supported by the NASA Postdoctoral Program at the NASA Goddard Space Flight Center, administered by Universities Space Research Association under contract with NASA. R. V. acknowledges funding from NSF awards AGS‐1261740 and AGS‐1620530. CONTRAST data are publicly available at “http://data.eol.ucar.edu/master_list/?project= CONTRAST.” ATTREX data are publicly available at “https://espoarchive.nasa.gov/archive/browse/attrex/id4/GHawk.” The National Center for Environmental Prediction (NCEP) meteorological data are available at “https://doi.org/10.5065/D6M043C6.” CCMI outputs from CESM1‐WACCM and CESM1‐CAM4Chem are archived by the National Center for Atmospheric Research (NCAR) at “www.earthsystemgrid.org,” and NCAR is sponsored by NSF. CCMI output from the EMAC‐L90MA‐SD simulation is available at “https://doi.org/10.5281/zenodo.1204495.” All other CCMI simulations are archived by the British Atmospheric Data Centre at “http://badc.nerc.ac.uk/”. Output from CAM‐chem‐SD is available as “NCAR/ACD CAMChem 1 Degree Forecast” at “http://catalog.eol.ucar.edu/contrast/model/CAMChem_NCAR_1deg/.” WACCM and CAM‐Chem are components of the Community Earth System Model (CESM), which is also supported by NSF. Computing resources were provided by NCAR's Climate Simulation Laboratory, sponsored by NSF and other agencies. This research was enabled by the computational and storage resources of NCAR's Computational and Information System Laboratory (CISL). R. S. and K. A. S., with ACCESS‐CCM, acknowledge support from Australian Research Council's Centre of Excellence for Climate System Science (CE110001028), the Australian Government's National Computational Merit Allocation Scheme (q90), and Australian Antarctic science grant program (FoRCES 4012). CCSRNIES research was supported by the Environment Research and Technology Development Fund (2‐1303 and 2‐1709) of the Ministry of the Environment, Japan, and computations were performed on NEC‐SX9/A(ECO) computers at the CGER, NIES. The EMAC simulations have been performed at the German Climate Computing Centre (DKRZ) through support from the Bundesministerium für Bildung und Forschung (BMBF). DKRZ and its scientific steering committee are gratefully acknowledged for providing the HPC and data archiving resources for the consortial project ESCiMo (Earth System Chemistry integrated Modelling). The TOMCAT modeling was supported by NERC NCAS and the SISLAC project (NE/R001782/1), and the simulations were performed on the Archer and Leeds HPC Systems.

The radial X-ray camera, which is used to measure magnetohydrodynamic phenomenon and monitor edge localised mode events, is a key diagnostic system for physics studies in the international thermonuclear experimental reactor (ITER) tokamak. Considering the special requirements of physics measurements and spatial resolution, 144 detector channels are required. The board card of the pre-amplifier is designed to improve the integration, on which 16 signal channels have been integrated. In order to suppress the noise and improve the stability of the pre-amplifier, the target impedance analysis method is applied in the design of the power supply, the trans-impedance amplifier and a two-stage active low pass filter are applied in the design. Simulation with Cadence OrCAD and ANSYS SIwave has been adopted to optimize the characteristics of the pre-amplifier. A test of the pre-amplifier shows its good performance for ITER application. After optimization of the pre-amplifier, the band width is 270 kHz, the amplification is 107 V/A, and the noise attenuation is − 30 dB, the noise of the pre-amplifier is reduced to 10 mV (noise of the power supply is included).

Sn-0.7Cu-0.05Ni is a widely used Pb-free solder that solidifies into a near-eutectic microstructure and a small fraction of primary Cu6Sn5. This paper overviews in-situ time-resolved imaging experiments on the solidification of Sn-0.7Cu-0.05Ni solder under three conditions: (i) directional solidification, (ii) continuous cooling in a near-uniform thermal field, and (iii) solder joint solidification on a Cu substrate. Primary Cu6Sn5 grow as rods along [0001] in each case but can also grow as X-shaped crystals in (iii). There are significant differences in eutectic growth due to nucleation difficulties for tin in conditions (ii) and (iii).

The exploration of anode materials for lithium ion batteries (LIBs) or sodium ion batteries (SIBs) represents a grand technological challenge to meet the continuously increased demand for the high-performance energy storage market. Here we report a facile and reliable synthetic strategy for in situ growth of few-layer MoS2 nanosheets on reduced graphene oxide (rGO) cross-linked hollow carbon spheres (HCS) with formation of three-dimensional (3D) network nanohybrids (MoS2-rGO/HCS). Systematic electrochemical studies demonstrate, as an anode of LIBs, the as-developed MoS2-rGO/HCS can deliver a reversible capacity of 1145 mAh g–1 after 100 cycles at 0.1 A g–1 and a revisible capacity of 753 mAh g–1 over 1000 cycles at 2 A g–1. For SIBs, the as-developed MoS2-rGO/HCS can also maintain a reversible capacity of 443 mAh g–1 at 1 A g–1 after 500 cycles. The excellent electrochemical performance can be attributed to the 3D porous structures, in which the few-layer MoS2 nanosheets with expanded interlayers can prov...

It's a challenge to prepare high-performance polymer solar cells (PSCs) employing non-halogenated solvents due to the poor solubility of conjugated polymers. Here, a new region-random copolymer, in contrast to traditional polymers featuring a D–A or D–π–A–π backbone, is synthesized and fully characterized. By polymerizing ffBT-T (π–A) units with BDT (D) units, the resultant polymer PBDT-ffBT-T (P1T) with repeat units of D–π–A or D–A–π exhibits superior solubility in non-halogenated solvents and outperforms its traditional analogues with the highest performance of 8.53% when processed from anisole. Importantly, the optimal device performance is attained with an active layer thickness of over 200 nm and shows no batch-to-batch difference, implying its compatibility with printing technology. Our results demonstrate that this simple chemical modification for copolymers may significantly benefit the development of PSCs using environmentally friendly solvents.