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Electrochemical CO2reduction reaction (eCO2RR) over Cu-based catalysts is a promising approach for efficiently converting CO2into value-added chemicals and alternative fuels. However, achieving controllable product selectivity from eCO2RR remains challenging because of the difficulty in controlling the oxidation states of Cu against robust structural reconstructions during the eCO2RR. Herein, we report a novel strategy for tuning the oxidation states of Cu species and achieving eCO2RR product selectivity by adjusting the Cu content in CuMgAl-layered double hydroxide (LDH)-based catalysts. In this strategy, the highly stable Cu2+species in low-Cu-containing LDHs facilitated the strong adsorption of *CO intermediates and further hydrogenation into CH4. Conversely, the mixed Cu0/Cu+species in high-Cu-containing LDHs derived from the electroreduction during the eCO2RR accelerated C–C coupling reactions. This strategy to regulate Cu oxidation states using LDH nanostructures with low and high Cu molar ratios produced an excellent eCO2RR performance for CH4and C2+products, respectively.

Producing high-quality joints between high-strength steel and aluminum alloy presents a challenge, yet it is crucial for manufacturing state-of-the-art lightweight. This study investigates self-piercing riveting (SPR) for joining high-strength steel to aluminum alloy panels. The experimental results for both steel-on-top (SOT) and steel-on-bottom (SOB) configurations are presented for a range of ultimate tensile strength (UTS) values of steel up to 1180 MPa. The findings show that the SOT configuration consistently produces high-quality joints, whereas the SOB configuration, especially with higher UTS steel panels, results in inadequate joints. To overcome the challenge of the SOB configuration, we propose a novel approach that uses reinforcing aluminum plates beneath the lap joints during the SPR process. The cross-sectional characteristics and mechanical performance of joints formed with varying thicknesses of reinforcing plates under both configurations are discussed. The results demonstrate that introducing the reinforcing plates in the SOB configuration effectively eliminates geometrical defects and ensures acceptable joint strength, even with high-strength steel.

Low-dimensional metal nanostructures have attracted considerable research attention, owing to their potential as catalysts. A controlled reductive phase transition of monolayer RuO2nanosheets could provide an effective way to produce holey large-area 2D Ru nanosheets with tailored defect structures and metal coordination number. The locally optimized holey Ru metal nanosheet, with a metal coordination number of ∼10.2, exhibited excellent electrocatalytic activity for the hydrogen evolution reaction (HER) with a reduced overpotential of 38 mV in a 1 M KOH electrolyte. The creation of a highly anisotropic holey nanosheet morphology with optimization of local structure was quite effective in developing efficient catalyst materials. The universal importance of controlling the coordination number was confirmed through a comparative study of Ru nanoparticles, which showed optimized HER activity with an identical metal coordination number. The coordination number plays a pivotal role in governing electrocatalytic activity, which could be ascribed to the formation of the most active structure for HER at most 2 defects near active sites (2,2′), resulting in the stabilization of a dihydrogen Ru–(H2) intermediate and the increased contribution of Volmer–Tafel mechanism.

Compared to polycrystalline semiconductors, amorphous semiconductors offer inherent cost-effective, simple and uniform manufacturing. Traditional amorphous hydrogenated Si falls short in electrical properties, necessitating the exploration of new materials. The creation of high-mobility amorphous n-type metal oxides, such as a-InGaZnO (ref. 1), and their integration into thin-film transistors (TFTs) have propelled advancements in modern large-area electronics and new-generation displays2–8. However, finding comparable p-type counterparts poses notable challenges, impeding the progress of complementary metal–oxide–semiconductor technology and integrated circuits9–11. Here we introduce a pioneering design strategy for amorphous p-type semiconductors, incorporating high-mobility tellurium within an amorphous tellurium suboxide matrix, and demonstrate its use in high-performance, stable p-channel TFTs and complementary circuits. Theoretical analysis unveils a delocalized valence band from tellurium 5pbands with shallow acceptor states, enabling excess hole doping and transport. Selenium alloying suppresses hole concentrations and facilitates the p-orbital connectivity, realizing high-performance p-channel TFTs with an average field-effect hole mobility of around 15 cm2V−1s−1and on/off current ratios of 106–107, along with wafer-scale uniformity and long-term stabilities under bias stress and ambient ageing. This study represents a crucial stride towards establishing commercially viable amorphous p-channel TFT technology and complementary electronics in a low-cost and industry-compatible manner.

The water oxidation reaction, the most important reaction for hydrogen production and other sustainable chemistry, is efficiently catalyzed by the Mn4CaO5cluster in biological photosystem II. However, synthetic Mn-based heterogeneous electrocatalysts exhibit inferior catalytic activity at neutral pH under mild conditions. Symmetry-broken Mn atoms and their cooperative mechanism through efficient oxidative charge accumulation in biological clusters are important lessons but synthesis strategies for heterogeneous electrocatalysts have not been successfully developed. Here, we report a crystallographically distorted Mn-oxide nanocatalyst, in which Ir atoms break the space group symmetry from I41/amdto P1. Tetrahedral Mn(II) in spinel is partially replaced by Ir, surprisingly resulting in an unprecedented crystal structure. We analyzed the distorted crystal structure of manganese oxide using TEM and investigated how the charge accumulation of Mn atoms is facilitated by the presence of a small amount of Ir.

Aqueous zinc–vanadium hybrid redox flow battery systems are an efficient strategy to address the problems of low voltage and high cost of conventional all-vanadium redox flow batteries. However, the low electrochemical activity of carbon-based electrodes toward a vanadium redox reaction limits the performance of redox flow batteries. In this study, polyhedral binary cerium titanium oxide (Ce2/3TiO3, CTO) is synthesized using molten salt synthesis. CTO is fabricated by adjusting the temperature and composition. Notably, the prepared CTO obtained at 1000 °C shows the highest catalytic activity for a VO2+/VO2+redox reaction. Further, CTO is prepared as a composite electrocatalyst and applied to a high-voltage aqueous zinc–vanadium redox flow battery. The cell adopts an alkali zinc electrolyte containing a Zn/[Zn(OH)4]2–redox pair and exhibits a high operating voltage of 2.26 V. Remarkably, a zinc–vanadium redox flow battery using the composite electrocatalyst exhibits a high energy density of 42.68 Wh L–1at 20 mA cm–2and an initial voltage efficiency of 90.3%. The excellent cell performance is attributed to structural defects caused by A-site deficiency in the perovskite oxide structure as well as oxygen vacancies resulting from the low valence state of the metal ion, which enhance the catalytic activity of the vanadium ions.

The construction of a desirable, environmentally friendly, and cost-effective nanoheterostructure photoanode to treat refractory organics is critical and challenging. Herein, we unveiled a hierarchical dendritic Co3O4–SnO2heterostructure via a sequential hydrothermal process. The time of the secondary hydrothermal process can control the size of the ultrathin SnO2nanosheets on the basis of the Ostwald solidification mass conservation principle. Ti/Co3O4–SnO2-168h with critical growth size demonstrated a photoelectrocatalysis degradation rate of ∼93.3% for a high dye concentrate of 90 mg/L with acceptable long-term cyclability and durability over reported Co3O4-based electrodes because of the large electrochemically active area, low charge transfer resistance, and high photocurrent intensity. To gain insight into the photoelectric synergy, we proposed a type-II heterojunction between Co3O4and SnO2, which prevents photogenerated carriers’ recombination and improves the generation of dominant active species •O2–, 1O2, and h+. This work uncovered the Ti/Co3O4–SnO2-168 as a promising catalyst and provided a simple and inexpensive assembly strategy to obtain binary integrated nanohybrids with targeted functionalities.

ABSTRACTThe chemical industry releases various types of volatile organic compounds (VOCs) into the atmosphere, and the concentration of VOCs emitted from chimneys is regulated worldwide. However, some VOCs such as benzene are highly carcinogenic, while others such as ethylene and propylene may cause secondary air pollution, owing to their high ozone-generating ability. Accordingly, the US EPA(United State, Environment Protect Agency) introduced a fenceline monitoring system that regulates the concentration of VOCs at the boundary of a facility, away from the chimney source. This system was first introduced in the petroleum refining industry, which simultaneously emits benzene, affecting the local community because of its high carcinogenicity, and ethylene, propylene, xylene, and toluene, which have a high photochemical ozone creation potential (POCP). These emissions contribute to air pollution. In Korea, the concentration at the chimney is regulated; however, the concentration at the plant boundary is not considered. In accordance with the EPA regulations, Korea’s petroleum refining industries were identified and the limitations of the Clean Air Conservation Act were studied. The average concentration of benzene at the research facility examined in this study was 8.53 µg/m3, which complied with the benzene action level of 9 µg/m3. However, this value was exceeded at some points along the fenceline, in proximity to the benzene-toluene-xylene (BTX) manufacturing process. The composition ratios of toluene and xylene were 27% and 16%, respectively, which were higher than those of ethylene or propylene. These results suggest that reduction measures in the BTX manufacturing process are necessary. This study shows that legal regulations should enforce reduction measures through continuous monitoring at the fenceline of petroleum refineries in Korea.Implications: Although volatile organic compounds(VOCs) are essential in various industrial sites, they adversely affect the health of people in the near community. Benzene is highly carcinogenic, so it is dangerous if exposed continuously. In addition, there are various types of VOCs, which combine with atmospheric ozone to generate smog. Globally, VOCs are managed as Total VOCs. However, through this study, VOCs have priority, and in the case of the petroleum refining industry, it is suggested that VOCs should be preemptively measured and analyzed to be regulated. In addition, it is necessary to minimize the impact on the local community by regulating the concentration at the fenceline beyond the chimney measurement.

Controlling the crystallinity and surface morphology of perovskite layers by methods such as solvent engineering1,2and methylammonium chloride addition3–7is an effective strategy for achieving high-efficiency perovskite solar cells. In particular, it is essential to deposit α-formamidinium lead iodide (FAPbI3) perovskite thin films with few defects due to their excellent crystallinity and large grain size. Here we report the controlled crystallization of perovskite thin films with the combination of alkylammonium chlorides (RACl) added to FAPbI3. The δ-phase to α-phase transition of FAPbI3and the crystallization process and surface morphology of the perovskite thin films coated with RACl under various conditions were investigated through in situ grazing-incidence wide-angle X-ray diffraction and scanning electron microscopy. RACl added to the precursor solution was believed to be easily volatilized during coating and annealing owing to dissociation into RA0and HCl with deprotonation of RA+induced by RA⋯H+-Cl−binding to PbI2in FAPbI3. Thus, the type and amount of RACl determined the δ-phase to α-phase transition rate, crystallinity, preferred orientation and surface morphology of the final α-FAPbI3. The resulting perovskite thin layers facilitated the fabrication of perovskite solar cells with a power-conversion efficiency of 26.08% (certified 25.73%) under standard illumination.

Single-atom catalysts have already been widely investigated for the nitrogen reduction reaction (NRR). However, the simplicity of a single atom as an active center encounters the challenge of modulating the multiple reaction intermediates during the NRR process. Moving toward the single-atom-dimer (SAD) structures can not only buffer the multiple reaction intermediates but also provide a strategy to modify the electronic structure and environment of the catalysts. Here, a structure of a vanadium SAD (V-O-V) catalyst on N-doped carbon (O-V2-NC) is proposed for the electrochemical nitrogen reduction reaction, in which the vanadium dimer is coordinated with nitrogen and simultaneously bridged by one oxygen. The oxygen-bridged metal atom dimer that has more electron deficiency is perceived to be the active center for nitrogen reduction. A loop evolution of the intermediate structure was found during the theoretical process simulated by density functional theory (DFT) calculation. The active center V-O-V breaks down to V-O and V during the protonation process and regenerates to the original V-O-V structure after releasing all the nitrogen species. Thus, the O-V2-NC structure presents excellent activity toward the electrochemical NRR, achieving an outstanding faradaic efficiency (77%) along with the yield of 9.97 μg h–1mg–1at 0 V (vs RHE) and comparably high ammonia yield (26 μg h–1mg–1) with the FE of 4.6% at −0.4 V (vs RHE). This report synthesizes and proves the peculiar V-O-V dimer structure experimentally, which also contributes to the library of SAD catalysts with superior performance.

Surface strain tuning in a coupled heterostructure efficiently engineers the catalytic performance of heterogeneous catalysts by altering the electronic structures and boosting electron transport. Generally, Bi-based catalysts are more favorable than ZnO for CO2electroreduction to formate, but Bi is much more costly than Zn. Herein, a new Bi2O2CO3/ZnO heterojunction catalyst with porous nanoplate morphology is synthesized through a hexadecyl trimethyl ammonium bromide-templated hydrothermal reaction for a highly efficient catalytic CO2reduction reaction (CO2RR) to produce formate. The Bi2O2CO3/ZnO catalyst shows a maximum Faradaic efficiency of 92% for formate production at −1.0 V vs. reversible hydrogen electrode (RHE) and a large partial current density of −200 mA mgBi−1at −1.2 V vs. RHE. More importantly, the mass activity of Bi2O2CO3/ZnO normalized by Bi mass is an approximately 3.1-fold enhancement over that of the pristine Bi2O2CO3at −1.2 V vs. RHE. By coupling X-ray photoelectron spectroscopy and adsorption spectroscopy measurements, the charge transfer from the Zn atom to the Bi atom through a heterogeneous interface results in an electron-enriched Bi2O2CO3surface, which facilitates CO2capture and activation. Meanwhile, compressive stress produced on the catalyst surface helps optimize the adsorption energy of the reaction intermediate, synergistically enhancing the catalytic selectivity and activity of Bi2O2CO3/ZnO for electrochemical CO2reduction to formate.

Trajectory tracking of underactuated marine vessels has become an intense research area in the nonlinear control community over the past two decades. In the authors’ previous work, an asymptotic tracking scheme was proposed by introducing two polar coordinate transformations, which can transform two-input-three-output underactuated system model into a certain two-input-two-output one. Therefore, it becomes possible to solve the trajectory tracking problem of these kinds of underactuated system using general backstepping method. However, since the polar coordinate transformation does not satisfy to be a diffeomorphism, the proposed tracking scheme in the polar frame cannot guarantee the same tracking performance in the Cartesian frame. With this consideration, in this paper the authors aim to analyze and establish a generalized condition under which the proposed tracking scheme in the previous work can guarantee the same tracking property in the Cartesian frame. The analysis results are verified through numerical studies as well.

The oxygen reduction reaction is essential for fuel cells and metal–air batteries in renewable energy technologies. Developing platinum-group-metal (PGM)-free catalysts with comparable catalytic performance is highly desired for cost efficiency. Here, we report a tin (Sn) nanocluster confined catalyst for the electrochemical oxygen reduction. The catalyst was fabricated by confining 1–1.5 nm sized Sn nanoclusters in situin microporous nitrogen-doped carbon polyhedra (SnxNC) with an average pore size of 0.7 nm. SnxNC exhibited high catalytic performance in acidic media, including positive onset and half-wave potentials, comparable to those of the state-of-the-art Pt/C and far exceeding those of the Sn single-atom catalyst. Combined structural and theoretical analyses reveal that the confined Sn nanoclusters, which have favorable oxygen adsorption behaviors, are responsible for the high catalytic performance, but not Sn single atoms.

The defect engineering of low-dimensional nanostructured materials has led to increased scientific efforts owing to their high efficiency concerning high-performance electrocatalysts that play a crucial role in renewable energy technologies. Herein, we report an efficient methodology for fabricating atomically thin, holey metal-phosphide nanosheets with excellent electrocatalyst functionality. Two-dimensional, subnanometer-thick, holey Ru2P nanosheets containing crystal defects were synthesized via the phosphidation of monolayer RuO2nanosheets. Holey Ru2P nanosheets exhibited superior electrocatalytic activity for the hydrogen evolution reaction (HER) compared to that exhibited by nonholey Ru2P nanoparticles. Further, holey Ru2P nanosheets exhibited overpotentials of 17 and 26 mV in acidic and alkaline electrolytes, respectively. Thus, they are among the best-performing Ru–P-based HER catalysts reported to date. In situ spectroscopic investigations indicated that the holey nanosheet morphology enhanced the accumulation of surface hydrogen through the adsorption of protons and/or water, resulting in an increased contribution of the Volmer–Tafel mechanism toward the exceptional HER activity of these ultrathin electrocatalysts.

We provide the rational design of dual atom catalysts (DACs) supported on nitrogen-doped graphene for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) through high-throughput computational screening of M1M2N6-DAC systems, where M1and M2represent Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, or Pt metals. We predict that FeRuN6-DAC at the summit of the volcano plot exhibits a low theoretical ORR overpotential (ηORR) of 0.24 V and a low theoretical OER overpotential (ηOER) of 0.19 V. The low ηORRand ηOERresult from the catalytic performance of the Fe site being tuned to electronic properties that facilitate adsorption and desorption of the OH* intermediate. Inspired by these hybrid density functional theory (DFT) computational and machine learning (ML) results, we synthesized FeRuN6-DAC, FeN4-SAC, and RuN4-SAC and characterized them using X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), scanning transmission electron microscopy (STEM), and in-situelectron spin resonance (ESR). Our in-situESR spectroscopy signifies that the spin of the Fe active site increases with increasing applied potential due to the increase in the concentration of OH* intermediate on Fe. We verified experimentally the predicted catalytic performances, finding that FeRuN6-DAC leads to an experimental ORR overpotential of 0.29 V with a Tafel slope of 104 mVdec−1and an OER overpotential of 0.27 V with a Tafel slope of 124 mVdec−1. The rechargeable Zinc-air battery setup was fabricated with FeRuN6-DAC in place of the cathode, showing a maximum power density of 0.45 W/cm2at the current density of 0.44 A/cm2and good stability after 120 cycles. According to our findings, we demonstrate that DFT-guided strategies are useful for designing advanced DACs applicable to ORR, OER, and Zinc-air battery applications.

Exploring single-atom catalysts (SACs) for the nitrate reduction reaction (NO3–; NitRR) to value-added ammonia (NH3) offers a sustainable alternative to both the Haber–Bosch process and NO3–-rich wastewater treatment. However, due to the insufficient electron deficiency and unfavorable electronic structure of SACs, resulting in poor NO3–-adsorption, sluggish proton (H*) transfer kinetics, and preferred hydrogen evolution, their NO3–-to-NH3selectivity and yield rate are far from satisfactory. Herein, a systematic theoretical prediction reveals that the local electron deficiency of an f-block Gd single atom (GdSA) can be significantly regulated upon coordination with oxygen-defect-rich NiO (GdSA-D-NiO400) support. Thus, facilitating stronger NO3–adsorption viastrong Gd5d–O2porbital coupling and further improving the protonation kinetics of adsorption intermediates by rapid H* capture from water dissociation catalyzed by the adjacent oxygen vacancy site along with suppressed H* dimerization synergistically boosts the NH3selectivity/yield rate. Motivated by DFT prediction, we delicately stabilized electron-deficient (strongly electrophilic) GdSAon D-NiO400(∼84% strong electrophilic sites), which exhibited excellent alkaline NitRR activity (NH3Faradaic efficiency ∼97% and yield rate ∼628 μg/(mgcath)) along with superior structural stability, as revealed by in situRaman spectroscopy, significantly outperforming weakly electrophilic Gd nanoparticles, defect-free GdSA-P-NiO400, and reported state-of-the-art catalysts.

Background Abatacept (Aba) is a cytotoxic T-lymphocyte antigen-4 and fragment crystallizable fusion protein. Aba blocks B7/Cluster of differentiation 28 - cytotoxic T-lymphocyte antigen-4 costimulatory pathway, inhibits cluster of differentiation 4+T-cell activation, and is used as an anti-inflammatory drug.Objectives We conducted this study to assess the effectiveness of Aba in the treatment of allergic rhinitis (AR) in a mouse model.Methods We divided 40 four-week-old BALB/c mice into four groups: control group (n= 10), positive control group (AR, n= 10), Aba group (AR + Aba, n= 10), and dexamethasone group (AR + Dex, n= 10). Mice in each group were challenged intranasally with daily ovalbumin (OVA) administration. Episodes of sneezing and nose rubbing were counted. Mice were sacrificed on day 42 and cytokines were measured in nasal lavage fluid. Nasal mucosae of five mice from each group were used for reverse transcriptase-polymerase chain reaction and western blot assay. Samples were collected from five mice from each group for histological analysis.Results Symptoms of AR significantly improved in the AR + Aba and AR + Dex groups compared with the AR group. Fewer eosinophils and goblet cells were seen in the AR + Aba and AR + Dex groups compared with the AR group. Both the AR + Aba and AR + Dex groups showed a significant decrease in nasal T helper 2 cytokine levels, including interleukin (IL)-4, IL-5, IL-13 and T cell activation related IL-17A, and interferon gamma (IFN- γ). Total immunoglobulin (Ig) E and OVA-specific IgG1 levels were also significantly lower in the AR + Aba and AR + Dex groups. OVA-specific IgE level was also significantly lower in the AR + Aba than AR group.Conclusions Aba suppresses allergic inflammation and appears to be a good treatment for AR.

Lithium-ion batteries and pseudocapacitors are nowadays popular electrochemical energy storage for many applications, but their cathodes and anodes are still limited to accommodate rich redox ions not only for high energy density but also sluggish ion diffusivity and poor electron conductivity, hindering fast recharge. Here, we report a strategy to realize high-capacity/high-rate cathode and anode as a solution to this challenge. Multiporous conductive hollow carbon (HC) nanospheres with microporous shells for high capacity and hollow cores/mesoporous shells for rapid ion transfer are synthesized as cathode materials using quinoid:benzenoid (Q:B) unit resins of coiled conformation, leading to ∼5-fold higher capacities than benzenoid:benzenoid resins of linear conformation. Also, Ge-embedded Q:B HC nanospheres are derived as anode materials. The atomic configuration and energy storage mechanism elucidate the existence of mononuclear GeOxunits giving ∼7-fold higher ion diffusivity than bulk Ge while suppressing volume changes during long ion-insertion/desertion cycles. Moreover, hybrid energy storage with a Q:B HC cathode and Ge–Q:B HC anode exploit the advantages of capacitor-type cathode and battery-type anode electrodes, as exhibited by battery-compatible high energy density (up to 285 Wh kg–1) and capacitor-compatible ultrafast rechargeable power density (up to 22 600 W kg–1), affording recharge within a minute.

Optically left-handed materials refract the propagating light in the opposite direction. Most research has focused on the design of various structures, including split-ring resonators, either on planes or in particle cluster forms to resonate with specific light frequencies. However, for particle-based materials, the circuital structures for optical left-handedness have not been fully understood and the effect of interior structure on the optical handedness have not been investigated. Additionally, scalable methods to deploy the unique characteristics of the materials have not been reported so far and are still urgent. Here, optically left-handed nanopearl beads are synthesized in up to 1.25 L solutions. Nanopearl beads contain assembled Au nanocolloids, a dielectric sphere, and a thin silica layer that fixes the assembled structures to sustainably yield unique inductance–capacitance circuits at specific visible-near-infrared frequencies. The frequencies are tunable by modulating the interior structures. Investigation of the circuit structures and Poynting vectors generated within the nanopearl beads suggest the likelihood of their left-handedness. Moreover, the effects of interior structures on the optical handedness of the nanopearl beads are extensively investigated. The results could help commercialize optically left-handed materials and pioneer fields that have not been realized so far.

Numerical weather prediction data, in this study, were proposed to replace the meteorological measurement data acquired by widely used radiosonde, for the purpose of constructing atmospheric environment model applying to post flight analysis, especially evaluating aerodynamic performance in flight. KLAPS (Korea Local Analysis and Prediction System), the numerical weather model used in this study, is provided by the Korea Meteorological Administration every hour through the Internet and contains the meteorological information for a local region around the Korean peninsula, which is expected to give some advantage in the acquisition of regional and temporal variation of atmosphere state over the radiosonde measurement which has some drawbacks of acquiring data on only one point at one height while drifting via wind and taking some hours to climb up to 30 km high. The accuracy of KLAPS was verified by regenerating vertical distributions of atmospheric properties at the same locations and times as radiosonde measured and comparing them. Post flight analysis was carried out with an atmosphere environment model based on KLAPS and proved that the numerical weather model can provide an accurate atmospheric environment model enough to substitute the radiosonde measurement data.

In perovskite solar cells, the interfaces between the perovskite and charge-transporting layers contain high concentrations of defects (about 100 times that within the perovskite layer), specifically, deep-level defects, which substantially reduce the power conversion efficiency of the devices1–3. Recent efforts to reduce these interfacial defects have focused mainly on surface passivation4–6. However, passivating the perovskite surface that interfaces with the electron-transporting layer is difficult, because the surface-treatment agents on the electron-transporting layer may dissolve while coating the perovskite thin film. Alternatively, interfacial defects may not be a concern if a coherent interface could be formed between the electron-transporting and perovskite layers. Here we report the formation of an interlayer between a SnO2electron-transporting layer and a halide perovskite light-absorbing layer, achieved by coupling Cl-bonded SnO2with a Cl-containing perovskite precursor. This interlayer has atomically coherent features, which enhance charge extraction and transport from the perovskite layer, and fewer interfacial defects. The existence of such a coherent interlayer allowed us to fabricate perovskite solar cells with a power conversion efficiency of 25.8 per cent (certified 25.5 per cent)under standard illumination. Furthermore, unencapsulated devices maintained about 90 per cent of their initial efficiency even after continuous light exposure for 500 hours. Our findings provide guidelines for designing defect-minimizing interfaces between metal halide perovskites and electron-transporting layers.

Background: Gastric cancer perforation is rare and difficult to distinguish from gastric ulcer perforation before surgery. Peritonitis caused by gastric perforation requires emergency surgery. The optimal surgical strategy for gastric perforation has not been established. Material and methods: Data from 43 patients who underwent primary gastrectomy with curative intent for gastric perforation between June 2010 and November 2019 were reviewed. Patients were classified into gastric ulcer and gastric cancer groups. Early surgical outcomes and overall survival were assessed. Results: There were no significant differences in clinical characteristics between the two groups except regarding preoperative shock. Laparoscopic gastrectomy was performed in 35 of 43 patients. There were no conversions to open surgery. The surgical findings demonstrated that the gastric cancer group had larger mass lesions with significantly larger perforations than did the gastric ulcer group. There were no significant differences in early surgical outcomes. Severe postoperative complications occurred in nine patients, five of whom died within one month of surgery. The majority of patients (90%) had stage III or IV gastric cancer. The 5-year survival rate was 19.5%. Conclusion: We found no definitive differences in clinical characteristics distinguishing gastric cancer from ulcers. Considering our surgical outcomes, laparoscopic primary gastrectomy performed by an expert is a useful technique for emergency gastric perforation. However, unless an expert is available, caution should be used when selecting laparoscopic primary gastrectomy with curative intent as a surgical method.

An effective lattice engineering method to simultaneously control the defect structure and the porosity of layered double hydroxides (LDHs) was developed by adjusting the elastic deformation and chemical interactions of the nanosheets during the restacking process. The enlargement of the intercalant size and the lowering of the charge density were effective in increasing the content of oxygen vacancies and enhancing the porosity of the stacked nanosheets vialayer thinning. The defect-rich Co–Al-LDH–NO3–nanohybrid with a small stacking number exhibited excellent performance as an oxygen evolution electrocatalyst and supercapacitor electrode with a large specific capacitance of ∼2230 F g–1at 1 A g–1, which is the largest capacitance of carbon-free LDH-based electrodes reported to date. Combined with the results of density functional theory calculations, the observed excellent correlations between the overpotential/capacitance and the defect content/stacking number highlight the importance of defect/stacking structures in optimizing the energy functionalities. This was attributed to enhanced orbital interactions with water/hydroxide at an increased number of defect sites. The present cost-effective lattice engineering process can therefore provide an economically feasible methodology to explore high-performance electrocatalyst/electrode materials.

In this paper, a robust controller using the back-stepping approach and the time delay estimation(TDE) is proposed for the 3D space motion control of torpedo-like autonomous underwater vehicles(AUVs). Due to the lack of control inputs, the vehicle dynamics does not satisfy the matching condition and has nonlinear dynamics including rigid dynamics and hydrodynamics. By utilizing a relevant coordinate transform, it is shown that the tracking error dynamics of the vehicles can be represented as a strict-feedback form. Using the error dynamics, the back-stepping controller is designed to gain robustness against the unmatched dynamics. The nonlinear dynamics of the vehicle is compensated by using the TDE which estimates the dynamics robustly utilizing the system inputs and outputs. By combining the back-stepping scheme and the TDE, the proposed controller has robust tracking performance against model uncertainties and disturbances. Owing simplicity of the TDE, moreover, the proposed controller can be implemented without necessity of whole dynamic model of the vehicles. The simulation results using the REMUS model demonstrates the robustness of the proposed controller against the model uncertainties and disturbances.

A total of 297 patients who classified as subscapularis (SC) tears through arthroscopic evaluation were retrospectively enrolled, and Fifty-seven patients with impingement syndrome were also enrolled as the control group for normal-population comparison. The coracohumeral distance (CHD) and humeral head anterior translation (HHAT) were measured on magnetic resonance imaging. Our study demonstrated that the anterior translation of the humeral head is related with a decrease in the coracohumeral distance in subscapularis tear. Although, correlation between radiologic parameters (coracohumeral distance and anterior translation of the humeral head) and severity of subscapularis tear was note detected.

This paper presents a controller IC with on‐display capacitive sensor for touch and multi fingerprint function. Single sensor and the IC enable both touch and fingerprint without additional area or sensor. Fully balanced multi‐channel driving technique with proposed method removes column offset to maximize the immunity to display and external noise. Prototype IC is fabricated in a 65nm CMOS technology. This work achieves 31.6dB SNR with 0.7mmϕ stylus and 120Hz frame rate with 14x10 pixels TSP in touch mode, and 32dB SNR with 0.2mm cover glass and 200ms scan time in multi‐fingerprint mode with 5cmx3.5cm area.

For the fabrication of perovskite solar cells (PSCs) using a solution process, it is essential to understand the characteristics of the perovskite precursor solution to achieve high performance and reproducibility. The colloids (iodoplumbates) in the perovskite precursors under various conditions were investigated by UV–visible absorption, dynamic light scattering, photoluminescence, and total internal reflection fluorescence microscopy techniques. Their local structure was examined by in situ X-ray absorption fine structure studies. Perovskite thin films on a substrate with precursor solutions were characterized by transmission electron microscopy, X-ray diffraction analysis, space-charge-limited current, and Kelvin probe force microscopy. The colloidal properties of the perovskite precursor solutions were found to be directly correlated with the defect concentration and crystallinity of the perovskite film. This work provides guidelines for controlling perovskite films by varying the precursor solution, making it possible to use colloid-engineered lead halide perovskite layers to fabricate efficient PSCs.

The impact of topological defects associated with grain boundaries (GB defects) on the electrical, optical, magnetic, mechanical and chemical properties of nanocrystalline materials1,2is well known. However, elucidating this influence experimentally is difficult because grains typically exhibit a large range of sizes, shapes and random relative orientations3–5. Here we demonstrate that precise control of the heteroepitaxy of colloidal polyhedral nanocrystals enables ordered grain growth and can thereby produce material samples with uniform GB defects. We illustrate our approach with a multigrain nanocrystal comprising a Co3O4nanocube core that carries a Mn3O4shell on each facet. The individual shells are symmetry-related interconnected grains6, and the large geometric misfit between adjacent tetragonal Mn3O4grains results in tilt boundaries at the sharp edges of the Co3O4nanocube core that join via disclinations. We identify four design principles that govern the production of these highly ordered multigrain nanostructures. First, the shape of the substrate nanocrystal must guide the crystallographic orientation of the overgrowth phase7. Second, the size of the substrate must be smaller than the characteristic distance between the dislocations. Third, the incompatible symmetry between the overgrowth phase and the substrate increases the geometric misfit strain between the grains. Fourth, for GB formation under near-equilibrium conditions, the surface energy of the shell needs to be balanced by the increasing elastic energy through ligand passivation8–10. With these principles, we can produce a range of multigrain nanocrystals containing distinct GB defects.