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Transcatheter arterial chemoembolization (TACE) has been widely used in clinical practice as a first-line treatment for unresectable hepatocellular carcinoma (HCC). However, the current therapeutic effect of TACE is far from satisfactory and thus requires further improvement. TACE combined with multifunctional magnetic particles may be a promising approach for the treatment of HCC. In this study, we designed a new magnetic drug carrier system consisting of micron-sized iron powder, barium ferrite (BaFe12O19), and carbon-coated iron nanocrystals (CCINs). CCINs possess properties, such as high drug loading and sustained release. BaFe12O19 could attract both CCINs and iron powder to form larger clusters after magnetization. Altogether, the triple therapeutic effects of chemotherapeutic enhancement, embolization, and thermal ablation could be realized herein. Further experiments indicate that the system has a high drug-loading capacity, good controlled-release effect, and no significant cytotoxicity. Under the action of a medium-frequency magnetic induction device, the magnetic induction temperature could reach 43 °C in one min while the maximum temperature of 70.8 °C could be reached in 2.5 hours. Overall, this new carrier system displayed excellent antitumor effects in a mouse model. Our findings demonstrate the great application prospects of this system in TACE for HCC.

Perovskite solar cells (PSCs) have become a promising alternative to sustainable energy due to their high power conversion efficiency (PCE) and low-cost processing. However, the practical applications of PSCs are still limited by the trade-off between high performance and poor stability under operation. Here, a 2D@3D perovskite with quasi core-shell architecture linking the superiorities of both two-dimensional (2D) and three-dimensional (3D) perovskite is prepared through a novel upgraded antisolvent approach. The basic properties as well as the phase distribution and the charge transport behavior of the 2D@3D perovskite were systematically elucidated. A high PCE of 21.60% for 2D@3D PSCs is achieved due to the enhanced surface and grain boundaries passivation, improved energy level alignment and efficient holes transport. The 2D@3D perovskite device without encapsulation shows significantly improved stability at the room temperature (90% of initial PCE for 45 d with a relative humidity of 50%±5%) and relative thermal conditions (83% of initial PCE for 200 h under 85 °C). Compared with traditional 3D PSCs, it proved that such 2D@3D perovskite configuration is an effective architecture for enhancing efficiency and improving stability and therefore will facilitate the further industrialization of PSCs.

Liquid phase sintering (LPS) is a proven technique for preparing large-size tungsten heavy alloys (WHAs). However, for densification, this processing requires that the matrix of WHAs keeps melting for a long time, which simultaneously causes W grain coarsening that degenerates the performance. This work develops a novel ultrashort-time LPS method to form bulk high-performance fine-grain WHAs based on the principle of laser additive manufacturing (LAM). During LAM, the high-entropy alloy matrix (Al0.5Cr0.9FeNi2.5V0.2) and W powders were fed simultaneously but only the matrix was melted by laser and most W particles remained solid, and the melted matrix rapidly solidified with laser moving away, producing an ultrashort-time LPS processing in the melt pool, i.e., laser ultrashort-time liquid phase sintering (LULPS). The extreme short dwell time in liquid (~1/10,000 of conventional LPS) can effectively suppress W grain growth, obtaining a small size of 1/3 of the size in LPS WHAs. Meanwhile, strong convection in the melt pool of LULPS enables a nearly full densification in such a short sintering time. Compared with LPS WHAs, the LULPS fine-grain WHAs present a 42% higher yield strength, as well as an enhanced susceptibility to adiabatic shear banding (ASB) that is important for strong armor-piercing capability, indicating that LULPS can be a promising pathway for forming high-performance WHAs that surpass those prepared by conventional LPS.

Many researches have shown that phosphorus doping can affect the photocatalytic activity, mainly because the incorporation of P atoms significantly alters the electronic, surface chemical, and properties of different semiconductors. However, excessive phosphorous doping will form the accumulation and recombination center of photo-generated charge carrier, thereby limiting the activity of photocatalytic reactions. In this work, we successfully prepared excessive P-doping g-C3N4 with ruthenium phosphide nanoparticles (RuxP/PCN), which had excellent performance of hydrogen evolution (1.94 mmol g−1 h−1). Specifically, C was replaced by P in the melon units of PCN and positive charge center (P+) was introduced, reinforcing the chemical connection between PCN and RuxP. In fact, excessive P+ centers became the traps and stacking centers of photo-generated carriers. However, due to the introduction of RuxP NPs, the accumulated charges in the P+ centers through the chemical bridges between PCN and RuxP NPs migrated to surface and then separated on RuxP NPs. Our research illustrates the mechanism of the accumulated charges caused by excessive phosphorus doping migrate to the surface and separate on phosphides, which can prolong the lifetime of photo-generated carriers. This result promoted the significant increase of photocatalytic hydrogen production activity. Our research clarifies the mechanism of excessive phosphorus doping and phosphides act on this photocatalytic system, which will provide a new way to design a photocatalytic system with higher HER performance.

Although organic redox molecules as electrode materials can achieve a high specific capacity through molecular design engineering, effective strategies to overcome their low cycling stability have not yet been developed. Herein, we establish a novel strategy that utilizes a strong dipole effect to suppress the high solubility of organic molecules and, thus, improve cycling stability. Two organic single crystals of squaraine derivative molecules with different substituents, 2,4-di(piperidin-1-yl)cyclobutane-1,3-dione (SAPD) and 2,4-di(pyrrolidin-1-yl)cyclobutane-1,3-dione (SAPL), were synthesized by facile routes. In particular, the SAPL cathode exhibited a discharge capacity of 371 mA h g–1 at 48 mA g–1 (0.1 C) and a nearly 78% capacity retention after 1000 cycles at 0.24 A g–1 (0.5 C). It also exhibited a capacity of 135 mA h g–1 even at 4.8 A g–1 (10 C) without hybridizing with graphene or carbon nanotubes. We studied the molecular interactions of SAPD and SAPL via detailed density functional theory calculations and revealed their lithium-ion storage mechanisms by using ex-situ technologies. Through comparing their intermolecular interactions, we found the stronger dipole effect can elevate cycling performance better. Hence, our design strategy can serve as a promising path for constructing high-performance lithium-organic batteries with long-term cycling stability.

Vanadium carbide (VC) as excellent ceramic and functional material is usually prepared by carbothermal reduction of V2O5 which must be extracted from a typical V slag by complex processes. Pollutants, such as ammonia-nitrogen wastewater, NH3 and CO2 are inevitably discharged. A novel and green method for VC preparation was proposed by one-step co-electrolysis of soluble NaVO3 and CO2 in molten salt. It was found that VC with high purity was easily obtained by reducing electrolysis temperature and CO2 flow rate to 600 °C and 10 mL min−1 at 3.0 V. Besides VC with particles and layered stacking structure in products, a small amount of carbon and oxygen elements existed. The atomic percentage contents of C, V, and O elements in VC were about 50.0%, 44.5% and 3.8%, respectively. During electrolysis, CO32− and VO3− was reduced at about −0.55 V (vs. Ag/AgCl) and −1.38 V (vs. Ag/AgCl), respectively. CO32− ions were more easily reduced than VO3−, and was firstly reduced to CO22− and then converted to C. Then, VC was prepared by two routes from CO2 and NaVO3. One route is that VO3− ions are firstly electroreduced to VO2− ions and then are further electroreduced to VC with C. Another route is that VO3− ions are electroreduced to V which in-situ reacted with C to VC. Both VO3− and CO32− ions are electroreduced by two-step process. In final, VC is in-situ deposited on cathode. It provides a novel and green way to prepare VC and also achieves the high value-added utilization of vanadium slag and CO2.

Astragali radix (AR, the dried root of Astragalus) is a popular herbal remedy in both China and the United States. The commercially available AR is commonly classified into premium graded (PG) and ungraded (UG) ones only according to the appearance. To uncover novel sensitive and specific markers for AR grading, we took the integrated mass spectrometry-based untargeted and targeted metabolomics approaches to characterize chemical features of PG and UG samples in a discovery set (n=16 batches). A series of five differential compounds were screened out by univariate statistical analysis, including arginine, calycosin, ononin, formononetin, and astragaloside Ⅳ, most of which were observed to be accumulated in PG samples except for astragaloside Ⅳ. Then, we performed machine learning on the quantification data of five compounds and constructed a logistic regression prediction model. Finally, the external validation in an independent validation set of AR (n=20 batches) verified that the five compounds, as well as the model, had strong capability to distinguish the two grades of AR, with the prediction accuracy > 90%. Our findings present a panel of meaningful candidate markers that would significantly catalyze the innovation in AR grading., Graphical abstract Image 1, Highlights • Five specific and reliable markers are uncovered to distinguish two grades of AR. • A logistic regression prediction model is built, with an accuracy of > 90%. • Most markers, but not astragaloside Ⅳ, exhibit accumulation in premium graded AR. • The findings are validated in an independent set by targeted LC-MS/MS analysis.

Hydrodechlorination is a promising technology for the remediation of water body contaminated with trichloroethylene (TCE). In this work, the liquid-phase hydrogenation of TCE by Raney Ni (R-Ni) and Pd/C under an open system have been studied, in which nascent H2 (Nas-H2) generated in situ from the cathode acted as a hydrogen source. Experimental results showed that TCE was completely eliminate from the solution through the synergistic effects of hydrodechlorination and air flotation due to the formation of continuous micro/nano-sized Nas-H2 bubbles from the cathode. Furthermore, the effects of inorganic anions and organic solvents on R-Ni and Pd/C hydrogenation activity were investigated, respectively. The results showed that NO3− and acetonitrile can form a competitive reaction with TCE; Sulfur with lone-pair electrons will cause irreversible poisoning to these two catalysts, and have a stronger inhibitory effect on Pd/C. This work helps to realize the separation of volatile halogenated compounds from water environment and provides certain data support for the choice of catalyst in the actual liquid-phase hydrogenation system.

In this study, molecular dynamics (MD) was used to simulate the rapid solidification process of Ni47Co53 and Ni48Co52 alloys at a cooling rate of 1012 K/s. The effects of HCP on the formation of twin boundaries and dislocations in two Ni–Co alloys are studied. It is found that the difference of HCP clusters is the main effect that producing discrepancies on microstructure of two alloys. The number of HCP clusters accounted for 9.23% in Ni47Co53 alloy. They are regularly arranged to form the number of single-layer twin boundaries, and each twin boundary ends in a dislocation. The FCC and HCP structures coexist in the same atomic layers, which is easy to create dislocations. The relatively standard FCC crystal and only 0.32% HCP clusters are formed in Ni48Co52 alloy at 300 K. That small amount of HCP clusters are dispersed on the surface, and cause the formation of dislocation in the border with FCC clusters.

The theory-practice gap (TPG) is well known in the environmental realm, referring to disconnects between knowledge generated through scientific research and the needs, expectations, and practices of knowledge users for environmental decision-making and practice. While the presence of the TPG is well established, we have yet to fully implement mechanisms for overcoming its challenges. Thus, our goal is to characterize the TPG and identify practical recommendations for minimizing it. Here, a diverse group of experts in the environmental realm (spanning landscape planning, conservation science, environmental sociology, resource management, political science, and anthropology, among others) present our perspectives on the TPG. More specifically, we share an organized framework for understanding the TPG and suggest recommendations that can help make progress in one or more dimension(s). Conceptual topics discussed are the implications of the gap and its persistence. Organizational/institutional topics include the implications of the overabundance, inaccessibility, and uncertainty of scientific information, and a need for mainstreaming boundary spanning activities. Lastly, cultural topics include differences in culture and epistemologies across knowledge generators and users, shifting cultures through co-production, and changes in educational curricula. Recommendations for minimizing the TPG include conceptually recasting what is considered ‘success,’ institutional reform, enhanced information delivery, leveraging knowledge brokers and boundary organizations, leveraging ‘champions’ in policy, using co-production and/or integrative research, confronting the contemporary ‘fake news’ phenomenon, and rethinking researcher and practitioner training and development. By sharing our framework and recommendations, we provide insight, as well as a starting point for those looking to narrow the TPG and improve knowledge generator-user relationships.

： In this paper, two dimensional Ti3C2Tx MXene nanosheets and one-dimensional Ni nanochains are successfully assembled into three dimensional porous MXene/Ni composite microspheres by ultrasonic spray. Their unique micro nano structure and well-designed three-dimensional porous interconnection network can significantly improve the stacking of Ti3C2Tx MXene nanosheets and the agglomeration of magnetic Ni nanochains. By changing the content of Ni nanochains，we can obtain MXene/Ni composite microspheres with different magnetic content. Due to the difference in conductivity between Ti3C2Tx MXene and Ni, as well as the newly generated hetero interface and abundant surface groups, MXene/Ni composite microspheres show good impedance matching and excellent electromagnetic wave absorption performance. The minimum reflection loss (RLmin) is −52.7 dB@12.8 GHz, and the corresponding matching thickness is only 1.9 mm. The preparation of MXene/Ni composite microspheres provides a simple and effective method for designing other MXene-based composite materials.

By the 2050s, more than 120 million people are predicted to settle in the Pearl River Delta (PRD), which covers large coastal cities such as Guangzhou, Shenzhen and Hong Kong. Cities in the PRD are vitally important to China in relation to their socio-economic contributions. From recent evidence, this strongly urbanized area is vulnerable to, and currently facing bigger incidences of, coastal and urban flooding. Flood risk is growing in low-lying coastal areas due to rapid urbanization and increasing flood hazards exacerbated by climate change. Frequent intensive rainstorms, sea-level rise, typhoons and surges threaten large populations and their economic assets, causing severe socio-economic and ecological impacts in the PRD cities. Current flood risk management (FRM) in the delta is still predominately focused on using traditional techno-fixes and infrastructure paradigms, lacking sufficient strategic planning and flood protection to develop adequate flood resilience. Recent urban floods, enhanced by storm surges and intensive rainstorms, have affected multiple PRD cities and drawn attention to flood risk as a major challenge in the PRD’s coastal cities. This review encourages development of long-term FRM practices with provincial and municipal authorities working together more closely to develop better-integrated regional FRM strategies for the PRD.

Hydratable magnesium carboxylate (HMC), which is similar to the properties of cement, can be used as a potential binder for refractory castables. However, its decomposition may lead to poor mechanical properties at medium temperatures (300 °C–1100 °C). This work investigated the effects of boric acid on the mechanical properties and microstructural evolution of castables bonded with hydratable magnesium carboxylate. The mechanical strength, bulk density, apparent porosity, thermal shock resistance, and sintering properties of the castables were evaluated. The results showed that the mechanical properties of HMC-bonded castables (HMCC) at various temperatures can be improved by adding boric acid. Boric acid reacts with HMC to form magnesium carboxylate borate ester (MCBE), which improves the bonding strength between HMC molecules. Thus, the cold modulus of rupture of HMCC containing boric acid dried at 110 °C are higher than that of calcium aluminate cement-bonded refractory castables (CACC). The decomposition temperature of MCBE is 77 °C higher than that of HMC, so MCBE can endow castables with better mechanical properties at 110 °C–500 °C. The B4C obtained by MCBE pyrolysis could form a boron-rich liquid phase, which can accelerate the structural densification of castables via transient liquid phase sintering, thus improving the mechanical properties of castables at 500 °C–1100 °C. Moreover, boric acid can improve the thermal shock resistance of HMCC. The residual strength rate first increases and then decreases with an increasing boric acid, and reaches a maximum value of 29.7% (1 wt% boric acid is added), which is 2.3 times that of the CACC. The nanoindentation test showed that the microcracks in the matrix of 1 wt% boric acid castables are easy to initiate but difficult to propagate, so the microcracks are many and wavy.

An accurate characterization of rocks for the modelling of creep is an essential step toward ensuring the safety with respect to reliability of underground rock engineering. In this work, a novel variable fractional order rheological model is established to describe the full-stage creep behavior of rocks. With simpler form and fewer parameters, the proposed model is verified to have the ability for the description of trimodal creep behavior of rocks. The evolution of mechanical properties during creep is quantitatively described by the variable fractional order including the creep hardening, softening and the transition part between them. Moreover, the physical significance of fractional order is further explored by the commonly accepted competition mechanism of creep hardening and softening for brittle creep, which indicates that the mechanical property of rocks during creep is harder with lower water contents but softens faster with larger applied stresses. Furthermore, the linear form of the variable order function is determined by applying the new variable order fractional operator. It is shown that the slope of order function confirms the creep strain rate and the intercept of order function primarily affects the critical time for entering the nonlinear creep phase. Finally, the rising tendency of fractional order reveals that the accelerating creep is a continuous softening process of mechanical properties since the larger values of fractional order exhibits the property of rocks is more viscous.

A high entropy alloy (HEA) with a composition of Ti2ZrMo0.5Nb0.5 was prepared by vacuum induction melting technology. The mechanical properties at room temperature and elevated temperature (900 °C–1150 °C), microstructure evolution and hot deformation behavior during hot deformation are studied. The as-cast alloy is composed of equiaxed grains with the yield strength, the apparent plastic strain of 1306 MPa and 44%, respectively. By TEM analysis, the ZrTi2 Laves C15 phase is found corresponding the precipitation strengthening effect accompanied with the solid solution strengthening as a ramification of the high-entropy alloy. Then the hot compression tests were carried out. The deformed alloy still maintains the same single BCC structure as the as-cast state. It is noted that when the temperature is 900 °C, the structure of the alloy mainly exhibits dynamic recovery (DRV) characteristics, and when the temperature reaches 1000 °C, there are clear dynamic recrystallization (DRX) characteristics in the structure, which are analyzed as the features of continuous dynamic recrystallization (CDRX). Keeping the temperature at 1150 °C, when the strain rate is 0.1 s−1, the characteristics of discontinuous dynamic recrystallization (DDRX) appear, and as the strain rate decreases, CDRX becomes the main recrystallization mechanism again.

The ionosphere characteristics are important for radio propagation and to monitor climate. At present, its research is confined to global scale or a single station. There are only few local area studies of ionosphere. In view of this situation, we will first verify the reliability of Global Ionosphere Map (GIM, IGS final products) in the Qinghai–Tibet Plateau, then implement low-power filtering and time series analysis to study the periodic, semiannual, and seasonal variation, the peak characteristic, and the “winter anomaly” phenomenon of the ionosphere. Finally, correlations between total electron content (TEC), solar activity indices, and geomagnetic indices are investigated, respectively, by executing quadratic polynomial fitting and establishing the relationship of TEC and F10.7p. The experimental results show that GIM is a reliable resource to research on the temporal and spatial characteristics of the ionosphere in the Qinghai–Tibet Plateau. The minimum TEC always occurs in autumn, whereas the maximum TEC occurs in spring or winter alternatively, which depends on the ascending or descending phase of solar activity. The “winter anomaly” phenomenon that existed for few years normally appears during the ascending phase of solar activity. The correlation coefficients of TEC with three solar activity indices, sunspot number, F10.7, and F10.7p are 0.79, 0.82, and 0.83, respectively, which show strong correlations between them. The correlation coefficients of TEC with three geomagnetic indices, Dst, Kp, and Ap are −0.48, 0.43, and 0.38, respectively, which show weak correlations between them. Quadratic polynomial regression of F10.7p and TEC is implemented. The regression line reflects that the ionosphere TEC in the Qinghai–Tibet Plateau has a saturated status.

Despite being difficult to identify, extremely dilute oxygen vacancies have been widely reported to play an important role in enhancing magnetism in ZnFe2O4. The mechanisms underlying this enhanced magnetism have not been well understood for a long time and remain controversial because the formation of oxygen vacancy-rich ZnFe2O4 can be accompanied by changes in the chemical/physical characteristics, especially the composition, particle size, surface morphology and cation distribution, which can significantly affect the magnetization. An open and important question is whether and to what extent the enhanced magnetization can be attributed only to oxygen vacancies. In this study, the relationship between the magnetization and oxygen vacancies in ZnFe2O4 was definitively determined by using a carefully designed “shake-and-heat” treatment to prepare vacancy-rich samples while keeping the other crystal/surface parameters constant. Compared to the nearly vacancy-free paramagnetism samples, the vacancy-rich samples exhibited a higher magnetization of approximately 5 emu/g at both 300 K and 2 K. The Fe3+-O2--Fe3+ superexchange paths broken by oxygen vacancies then resulting in the Fe3+-Fe3+ ferromagnetism configuration. Meanwhile, the oxygen vacancy is highly diluted then the ferromagnetism configuration is confined in a single super-cell, favoring a short-range magnetic ordering at room temperature. The concentration of oxygen vacancies was calculated to be 0.68% by magnetization measurement. Our results may shed a light on how oxygen vacancies affect magnetism.

To improve the combustion stability at micro scale, the micro combustor with a central and bilateral slotted blunt body (MCSB) exhibiting significant combustion performance improvement is designed. The new one can not only effectively prevent the flame tip opening, but also exhibit higher combustion efficiency and blown-off limit. Its blown-off limit can reach 756 cm3/s at the flow rate ratio of 0.2 and the bluff body angle of 90°, which is 61.5% higher than that of the conventional one with the blown-off limit of 468 cm3/s. The combustion efficiency improves with the growth of the flow rate ratio, while the blown-off limit of MCSB increases first and then decreases. The blown-off limit of MCSB with the bluff body angle of 90° reaches to the peak value of 792 cm3/s at the flow rate ratio of 0.15. Moreover, the increase of the bluff body angle provides better combustion efficiency and stability.

Micro-scale combustion is facing the problems of ignition difficulty, combustion instability, and low combustion efficiency. Therefore, it is necessary to improve the combustion characteristics in micro-combustor to expand the application range of micro-combustor. Focusing on the problem of the weak preheating effect of the micro cavity-combustor, the guide vanes are constructed to enhance the combustion near the cavity, and further combine with the bluff body to enhance combustion. The combustion characteristics of three types of cavity combustors with guide vanes (CCGV), bluff body (CCBB), bluff body, and guide vanes (CCGB) respectively are compared and analyzed under different inlet velocities (8–32 m/s), equivalence ratios (0.6–1.4), and wall materials (quartz glass, steel, and SiC). Results show that the guide vanes can greatly improve the combustion intensity near the cavity and improve the combustion stability of the cavity combustor. The combustion efficiency of CCGV and CCGB are increased by 43.04% and 85.96% respectively than CCBB when the inlet velocity is 32 m/s. The reaction heat of CCGV is 244.5 W when inlet velocity is 32 m/s, which is 0.55 times and 1.57 times that of CCGV and CCBB, respectively. The temperature uniformity and mean temperature of the outer wall of CCGV and CCGB both are better than that of CCGB. The combustion efficiency of CCGB is the highest among three combustors under the same equivalence ratio, especially when the equivalence ratio is less than 1. The reaction intensity in the cavity of the CCGV and CCGB with steel wall material is highest than that of the combustor with the other two wall materials. Wall materials with high thermal conductivity have a better preheating effect. Compared with quartz as the wall material, the mean temperature of the external wall of CCGV and CCGB using steel and silicon carbide as the wall material both increase by more than 130 K, and the wall heat loss both increase by more than 50%.

Energy consumption prediction can provide reliable data support for energy scheduling and optimization of office buildings. It is difficult for traditional prediction model to achieve stable accuracy and robustness when energy consumption mode is complex and data sources are diverse. Based on such situation, this paper raised an approach containing the method of comprehensive similar day and ensemble learning. Firstly, the historical data was analyzed and calculated to obtain the similarity degree of meteorological features, time factor and precursor. Next, the entropy weight method was used to calculate comprehensive similar day and applied to the model training. Then the improved sine cosine optimization algorithm (SCA) was applied to the optimization and parameter selection of a single model. Finally, an approach of model selection and integration based on dominance was proposed, which was compared with Support Vector Regression (SVR), Back Propagation Neural Network (BPNN), Long Short-Term Memory (LSTM), with a large office building in Xi ‘an taken as an example to analysis showing that compared with the prediction accuracy, root mean square percentage error (RMSPE) in the ensemble learning model after using comprehensive similar day was reduced by about 0.15 compared with the BP model, and was reduced by about 0.05, 0.06 compared with the SVR and LSTM model. Respectively, the mean absolute percentage error (MAPE) was reduced by 12.02%, 6.51% and 5.28%. Compared with several other integration methods, integration model based on dominance reduced absolute error at all times. Accordingly, the proposed approach can effectively solve problems of low accuracy and poor robustness in traditional model and predict the building energy consumption efficaciously.

Hg2+ toxicity is one of the most common chemical poisonings that occurs mainly from drinking polluted water. In the current work, Phycocyanin (PC) was exploited as a fluorescent sensor for sensitive and selective detection of Hg2+ in an aqueous system. PC-Hg2+ interaction was monitored using a spectro-fluorometer under different buffered solutions at pH values of 6,7,8,9, or 10 above the isoelectric point of PC (5.18). A remarkable decrease of PC fluorescence intensity was observed under Tris-buffer at pH 6 upon the addition of increasing Hg2+ concentrations (1-120 nM). Under the maintained experimental conditions, the current sensor showed a good linear relationship with R2 = 0.9971 and a limit of detection as low as 0.7 nM was achieved. In addition, a notable selectivity of Hg2+ over other nine heavy metals (Cu2+, Zn2+, Pb2+, Mg2+, Mn4+, Li+, Fe3+, Co2+, and Al3+) was achieved in the presence of 120 nM of each metal. Moreover, the current fluorescent detection assay was also tested in real samples of pond water, and recoveries as well as relative standard deviations within the acceptable limits were recorded.

China has become the world’s most carbon-emitting country, and the coal-fired power industry (CFPI) dominates China’s carbon emissions. Stimulating the carbon emission reduction potential of China’s CFPI is important for reducing global carbon emissions and mitigating global warming. To explore the potential for reducing carbon emissions in the CFPI, this study constructed a model based on the data envelopment analysis (DEA) method, considering profit motive and the cost of regulatory policy. To analyze the factors influencing carbon reduction potential (CRP), the Kaya-LMDI (Kaya Identity-Logarithmic Mean Divisia Index) method was also applied. Some policy implications for the regions in China came out. The results show that: (a) China’s coal power industry generation process has not yet reached its optimal profit. When China’s CFPI realizes the optimal profit, a CRP will also decrease industrial carbon emissions by 3.54%. (b) At the carbon costs ranging from 16.8 to 95.2 Yuan/ton caused by carbon regulation policy, the total CRP of China’s CFPI would be further enhanced to 4.32%. (c) The coal-fired power output rate and industry scale had a positive effect on CRP, while the labor productivity had a negative effect. Carbon costs caused by carbon regulation policies could promote the CFPI to realize a greater carbon emission reduction potential by adjusting labor productivity and the industry scale effect.

Combining photodynamic therapy (PDT), chemodynamic therapy (CDT), and ferroptosis is a valuable means for an enhanced anticancer effect. However, traditional combination of PDT/CDT/ferroptosis faces several hurdles, including excess glutathione (GSH) neutralization and preparation complexity. In this work, a versatile multifunctional nanoparticle (HCNP) self-assembled from two porphyrin molecules, chlorin e6 and hemin, is developed. The as-constructed HCNPs exhibit a peroxidase-mimic catalytic activity, which can lead to the in situ generation of endogenous O

Replacing natural gas with the environmentally sustainable biogas is a promising way to reduce the usage of fossil fuels and promote organic waste utilization. Micro gas turbine (MGT), as a common power supply machine, is capable of adopting biogas as the fuel. Given the different intrinsic components between natural gas and biogas, combustion performance of biogas in MGT was studied in this work. The effects of fuel composition and excess air coefficient on combustion performance were analyzed through three-dimensional numerical simulation of the MGT combustor. RNG k-e turbulent model, eddy-dissipation/finite rate model, and eight-step reaction mechanism were adopted in the simulation. The results showed that when the CO2 percentage in biogas increases, the NO and CO emissions decreases. However, the fuel rate and pressure drop of combustion chamber increases to maintain constant thermal input. The overall high velocity also increases the requirement for materials of combustion chamber. Furthermore, the average temperature of whole combustor decreases when the excess air coefficient increases. Accordingly, the CO2 mole fraction in biogas should be controlled below 30% and the optimal range of the excess air coefficient is 2–2.5 for the MGT.

The Mount Wilson magnetic classification of sunspot groups is thought to be meaningful to forecast flares’ eruptions. In this paper, we adopt a deep learning method, CornerNet-Saccade, to perform the Mount Wilson magnetic classification of sunspot groups. It includes three stages, generating object locations, detecting objects, and merging detections. The key technologies consist of the backbone as Hourglass-54, the attention mechanism, and the key points’ mechanism including the top-left corners and the bottom-right corners of the object by corner pooling layers. These technologies improve the efficiency of detecting the objects without sacrificing accuracy. A dataset is built by a total of 2486 composited images which are composited with the continuum images and the corresponding magnetograms from HMI and MDI. After training the network, the sunspot groups in a composited solar full image are detected and classified in 3 seconds on average. The test results show that this method has a good performance, with the accuracy, precision, recall, and mAP as 0.94, 0.93, 0.94, and 0.90, respectively. Moreover, the flare productivities of different types of sunspot groups from 2011 to 2020 are calculated. As I tot ≥ 1, the flare productivities of α , β , β γ , β δ , and β γ δ sunspot groups are 0.14, 0.28, 0.61, 0.71, and 0.87, respectively. As I tot ≥ 10, the flare productivities are 0.02, 0.07, 0.27, 0.45, and 0.65, respectively. It means that the β γ , β δ , and β γ δ types are indeed very closely related to the eruption of solar flares, especially the β γ δ type. Based on the reliability of this method, the sunspot groups of the HMI solar full images from 2011 to 2020 are detected and classified, and the detailed data are shared on the website (https://61.166.157.71/MWMCSG.html).

Single-atom catalysts (SACs), with atomically dispersed metal atoms anchored on a typical support, representing the utmost utilization efficiency of the atoms, have recently emerged as promising catalysts for a variety of catalytic applications. The electronic properties of the active center of SACs are highly dependent on the local environment constituted by the single metal atom and its surrounding coordination elements. Therefore, engineering the coordination environment near single metal sites, from the first coordination shell to the second shell or higher, would be a rational way to design efficient SACs with optimized electronic structure for catalytic applications. The wide range of coordination configurations, guaranteed by the multiple choices of the type and heterogeneity of the coordination element (N, O, P, S, etc.), further offer a large opportunity to rationally design SACs for satisfactory activities and investigate the structure–performance relationship. In this review, the coordination engineering of SACs by varying the type of coordination element was elaborated and the photocatalytic water splitting of SACs was highlighted. Finally, challenging issues related to the coordination engineering of SACs and their photocatalytic applications were discussed to call for more efforts devoted to the further development of single-atom catalysis.

The energy output and energy conversion efficiency of MTPV system are relatively low due to the energy loss. In order to improve the energy output of micro-thermophotovoltaic (MTPV) system, the internal straight and spiral fins are introduced into the micro combustor. The impact of hydrogen mass flow rate, equivalence ratio, and materials on the thermal performance are investigated. The increase of hydrogen mass flow rate brings higher average outer wall temperature, but the temperature difference also increases and the temperature uniformity becomes worse. The equivalence ratio of 1 is suggested to obtain higher average outer wall temperature and better temperature uniformity. The materials with higher thermal conductivity can obtain better thermal performance. Meanwhile, the higher thermal conductivity can also reduce the impact of introduction of internal fins.

Strain modulation is crucial for heteroepitaxy such as GaN on foreign substrates. Here, the epitaxy of strain-relaxed GaN films on graphene/SiC substrates by metal-organic chemical vapor deposition is demonstrated. Graphene was directly prepared on SiC substrates by thermal decomposition. Its pre-treatment with nitrogen-plasma can introduce C–N dangling bonds, which provides nucleation sites for subsequent epitaxial growth. The scanning transmission electron microscopy measurements confirm that part of graphene surface was etched by nitrogen-plasma. We study the growth behavior on different areas of graphene surface after pre-treatment, and propose a growth model to explain the epitaxial growth mechanism of GaN films on graphene. Significantly, graphene is found to be effective to reduce the biaxial stress in GaN films and the strain relaxation improves indium-atom incorporation in InGaN/GaN multiple quantum wells (MQWs) active region, which results in the obvious red-shift of light-emitting wavelength of InGaN/GaN MQWs. This work opens up a new way for the fabrication of GaN-based long wavelength light-emitting diodes.

The precipitation hardening and intergranular corrosion behavior of Al–Mg alloys with Ag and Si additions are systematically investigated. Results reveal that both alloys present an obvious aging hardening. However, the addition of Si in Al–Mg alloy presents poor intergranular corrosion resistance. After the addition of Ag, mechanical properties and intergranular corrosion resistance of the alloy are both improved. Ag promotes the precipitation of nanoscale MgAg phase and Q' phase (Mg9Si7Ag2Al3) inner grain, which contribute to the improvement of aging strengthening. Besides, precipitate-free zone (PFZ) and consecutive Si segregation band are diminished by Ag-addition. Therefore, the intergranular corrosion resistance of the alloy is improved by Ag.

The high driving electric field and the large strain hysteresis are subject to a challenge for piezoelectric actuators’ practical applications. In order to obtain the piezoceramics with giant strain and low hysteresis at small electric field, a ternary solid solution (0.97-x)(K0.48Na0.52)Nb0.965Sb0.035–0.03Bi0.5(K0.18Na0.82)0.5ZrO3-xBaZrO3 (x = 0–0.06) was designed and synthesized by the traditional solid-state reaction method. The relationships among phase transition, microstructure, and electrical properties of the ceramics samples were systemically investigated. Under a low electric field of 4 kV/mm, the ceramic with x = 0.02 obtained a high bipolar strain of 0.29% (Smax/Emax = 729 pm/V) and a low hysteresis of 13.8%. The excellent piezoelectric properties are mainly attributed to rhombohedral–orthorhombic–tetragonal (R–O–T) phase boundary and the relaxor-to-ferroelectric phase transition. We believe that our research can not only provide the pathway of achieving KNN-based ceramics with high strain and low hysteresis but also promote the practical application of lead-free piezoelectric actuators.

A radical nitrohalogenation/cyclization of various enynes with tert-butyl nitrite has been developed that conveniently introduces useful nitro and halo groups into organic compounds. Some control experiments were performed to elucidate the mechanism. Further functional transformations proceeded well in this reaction system.

Multiple displacement amplification (MDA) is a popular single-cell whole-genome amplification (WGA) technique that can greatly improve the amplification efficiency of single-cell genomes. However, there is an inherent problem that cannot be completely solved, that is, the amplification bias. We here propose an improved MDA method based on low melting agarose gel, named gelMDA. Firstly, the agarose gel and solution were characterized with SEM and fluorescent reagent. Then, we used gelMDA for cDNA amplification in library preparation of RNA-seq, and conventional MDA was used as a comparison. The sensitivity, efficiency of gelMDA, and amplification bias were evaluated with fluorescence curve, product yield, and the sequencing results. Finally, gelMDA was used for single-cell transcriptome sequencing. The results showed that the sensitivity and product yield of gelMDA were significantly higher than those of conventional MDA. A lower coefficient of variation (CV) and a higher reproducibility were obtained from gelMDA sequencing results. A region of 30 μm in diameter was amplified from the tissue sections and successfully sequenced. In conclusion, gelMDA obtained higher amplification efficiency and lower amplification bias in the present study. It suggested the great potential in single-cell RNA amplification and sequencing.

Nowadays, wearable technology and the Internet of Things (IoT) are transforming the healthcare sector by refining the way how devices, applications, and people connect and interact with each other. IoT applications in sports are tremendously useful to monitor health and reduce the risk factor. The battery life of wearable and accurate monitoring has been considered a significant challenge in sports medicine. Hence, in this paper, Energy Efficient IoT based Improved Health Monitoring system (EEIoT-IHMS) has been proposed for accurate and continuous sports person’s health monitoring system. This paper determines the optimal set of clusters based on sensor features, in which power usage has been minimized by duty cycling with optimized prediction accuracy. The experimental results demonstrate that the proposed (EEIoT-IHMS) enhances accuracy ratio, improves battery life, and reduces energy consumption compared to other popular methods.

Low-cost transition-metal oxide is regarded as a promising electrocatalyst family for an oxygen evolution reaction (OER). The classic design principle for an oxide electrocatalyst believes that point defect engineering, such as oxygen vacancies (VO..) or heteroatom doping, offers the opportunities to manipulate the electronic structure of material toward optimal OER activity. Oppositely, in this work, we discover a counterintuitive phenomenon that both VO.. and an aliovalent dopant (i.e., proton (H+)) in perovskite nickelate (i.e., NdNiO3 (NNO)) have a considerably detrimental effect on intrinsic OER performance. Detailed characterizations unveil that the introduction of these point defects leads to a decrease in the oxidative state of Ni and weakens Ni-O orbital hybridization, which triggers the local electron-electron correlation and a more insulating state. Evidenced by first-principles calculation using the density functional theory (DFT) method, the OER on nickelate electrocatalysts follows the lattice oxygen mechanism (LOM). The incorporation of point defect increases the energy barrier of transformation from OO*(VO) to OH*(VO) intermediates, which is regarded as the rate-determining step (RDS). This work offers a new and significant perspective of the role that lattice defects play in the OER process.

Thioredoxin (TRX) is a highly conserved low-molecular-weight protein and a ubiquitous antioxidant enzyme that plays key role in the regulation of plant growth and development. Here, using the whole-genome sequence, we performed a systematic analysis for the TRX gene family in upland cotton (Gossypium hirsutum L.) and analyzed their structural characteristics, evolution, and expression profiles during growth and development. At least 86 GhTRX members, 40 typical and 46 atypical, were identified in the cotton genome, and they were unevenly distributed on the 26 chromosomes. Conserved domains and phylogenic tree construction classified the typical TRX gene family into seven subfamilies and the atypical TRX into nine subfamilies. An evolutionary analysis revealed that the TRX gene family underwent purification selection during evolution. In addition, an RNA-Seq analysis showed that, during vegetative and reproductive development, the differences in transcript abundance levels and organ-specific expression patterns suggest functional diversity. Biochemical assays demonstrated that the atypical TRX protein GhTRXL3-2 interacted with the cotton FLOWERING LOCUS T protein GhFT. The overexpression of GhTRXL3-2 in Arabidopsis thaliana resulted in early flowering compared with control plants. Additionally, the silencing of GhTRXL3-2 in cotton delayed maturation, suggesting that it has important roles in cotton’s flowering regulation. These results help clarify the evolution of the TRX genes and elucidate their biological functions in cotton flowering regulation.

The combination of solution IR spectroscopy measurement, fast cooling crystallization experiments, conformational search, and molecular computation was investigated in detail in this study to explo...

Studying electronic structure plays a key role in improving the photoluminescence (PL) properties of materials. Therefore, the electronic structure of YF3: xEu3+ with different Eu3+ ions doping concentrations was explored by first-principles calculations based on density functional theory (DFT). As calculated, the YF3 host had an indirect bandgap of 7.68 eV. From all calculation results we got, the band structure of YF3: xEu3+ exhibited the smallest direct band gap of 6.54 eV when the value of x was 0.10. This small direct band gap is beneficial to obtain excellent emission intensity. Besides, the morphologies and sizes have a significant influence on the fluorescence intensity of the products. A series of YF3: xEu3+ phosphors with leaf-like, spindle-like, pecan-like, and granular-like morphologies were obtained by changing the RE3+/NaF ratio via a microwave hydrothermal method. At the same time, the formation process of granule-like YF3: Eu3+ was explored through time-dependent experiments. Furthermore, the fluorescence performance of YF3: xEu3+ was studied in detail. The as-obtained YF3: xEu3+ can exhibit orange-red emission under ultraviolet excitation because of the magnetic dipole of the 5D0–7F1 transition of Eu3+ ions. After comparing the luminescence properties of samples with different morphologies, we found that the sample with granule-like morphology had the highest orange-red emission intensity. The experimental result proved that the appropriate Eu3+ ions doping concentration were x = 0.10, which is highly consistent with the calculation result.

Hollow hydroxyapatite microspheres (HHAM), a type of mesoporous nanomaterials with a specific internal cavity and hierarchical architectures, have attracted enormous interest over the past years owing to their remarkable potential for biomedical applications. However, the as-obtained HHAM fail to meet the need of the ever-updating diagnosis, treatment, and theranostics technologies. With the attempt to enhance performances and expand applications of HHAM, scientists have tailored the properties of HHAM by various methods including -doping modification and surface functionalization to give a versatile type of biomaterials, i.e., functionalized hollow hydroxyapatite microspheres (f-HHAM). Actually, significant achievements in the realm of f-HHAM have been obtained and various intractable clinic problems have been resolved. Nevertheless, designing desirable f-HHAM is expected to accelerate the development of the biomedicine field. In this contribution, the state-of-the-art progress f-HHAM is overviewed, which covers from the developments and preparation methods to bioapplications of these biomaterials. In addition, the current trends and key points as well as the future prospects and challenges for the applications of f-HHAM are discussed, aiming at providing a guideline for rational design of more creative f-HHAM according to different therapeutic requirements.

A series of multi-component fluoride-containing phosphate-based glasses prepared in a reducing atmosphere showed improved resistance to high-energy ultraviolet (UV) laser-induced damage and strong laser-induced fluorescence (LIF) within the glass bulk. The UV optical absorption, photoluminescence, and fluorescence decay properties of these glasses were investigated to explore the defect-related LIF mechanism and its underlying effect on the glasses’ laser-induced damage threshold (LIDT). Seven laser wavelengths ranging from 253 nm to 532 nm were used to excite the LIF, and two characteristic fluorescence bands peaking at approximately 414 nm and 780–800 nm occurred in all three types of glasses. The LIF band at 414 nm was attributed to PO3-EC defects in the second harmonic frequency (2ω) absorptive glass and third harmonic frequency (3ω) transparent glass, but Fe2+ ions in the fundamental frequency (1ω) absorptive glass. A later fluorescence band at 780–800 nm occurred due to POHC defects in the 2ω absorptive and 3ω transparent glasses and Fe3+ ions in the 1ω absorptive glass. A detailed study on the dynamic decay processes of two additional dominant fluorescence peaks at 450 nm and 780 nm under 266 nm excitation revealed the potential effect of LIF on LIDT improvement. The relatively longer LIF lifetime, higher LIF intensity, and larger LIF peak area corresponded with and contributed to a higher LIDT, especially in the 3ω transparent glass with a low UV absorption coefficient. This study provides strong evidence for the prior hypothesis between strong LIF and LIDT.

Clouds and precipitation have vital roles in the global hydrological cycle and the radiation budget of the atmosphere–Earth system and are closely related to both the regional and the global climate. Changes in the status of the atmosphere inside clouds and precipitation systems are also important, but the use of multi-source datasets is hampered by their different spatial and temporal resolutions. We merged the precipitation parameters measured by the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) with the multi-channel cloud-top radiance measured by the visible and infrared scanner (VIRS) and atmospheric parameters in the ERA5 reanalysis dataset. The merging of pixels between the precipitation parameters and multi-channel cloud-top radiance was shown to be reasonable. The 1B01-2A25 dataset of pixel-merged data (1B01-2A25-PMD) contains cloud parameters for each PR pixel. The 1B01-2A25 gridded dataset (1B01-2A25-GD) was merged spatially with the ERA5 reanalysis data. The statistical results indicate that gridding has no unacceptable influence on the parameters in 1B01-2A25-PMD. In one orbit, the difference in the mean value of the near-surface rain rate and the signals measured by the VIRS was no more than 0.87 and the standard deviation was no more than 2.38. The 1B01-2A25-GD and ERA5 datasets were spatiotemporally collocated to establish the merged 1B01-2A25 gridded dataset (M-1B01-2A25-GD). Three case studies of typical cloud and precipitation events were analyzed to illustrate the practical use of M-1B01-2A25-GD. This new merged gridded dataset can be used to study clouds and precipitation systems and provides a perfect opportunity for multi-source data analysis and model simulations. The data which were used in this paper are freely available at https://doi.org/10.5281/zenodo.4458868 (Sun and Fu, 2021).

An iron-catalyzed allyation of isoquinoline with potassium allyltrifluoroborate is described. The operation of this reaction is very simple and highly practical. The diastereoisomer having two adjacent chiral centers were obtained in single anti-configuration.

Soil moisture plays an important factor to impact runoff and the slope stability, but how vegetation affects the soil moisture variability of slope stability is poorly understood. In order to compare the stability of different shrub slopes under the effect of soil moisture, four types of shrubs (Periploca sepium, Lespedeza bicolor, Ziziphus jujuba, and Punica granatum) are selected for ecological restoration in shallow landslide-prone areas, and the effects of rhizosphere soil moisture and plant roots on the slope stability are studied. Trace infiltration is applied in order to study plant roots and soil moisture impact. The shear strength of the roots slope soil under different moisture content is determined by laboratory shear strength test. The slope safety factor of different shrubs is obtained by FLAC 3D (Fast Lagrangian Analysis of Continua 3D) simulation. Among the four shrubs, thick roots show the greatest improvement to soil porosity, and fine and medium roots could provide more preferential flow channels for water infiltration. The soil moisture content significantly increases after planting Lespedeza bicolor. At 10% soil moisture content, the P. sepium slope safety factor is highest in four shrubs (1.39). When the soil moisture content reaches 30%, the safety factor value of the L. bicolor slope reaches the maximum, and the safety factor value of L. bicolor decreased by 25.6%. The results show that even during the wettest condition of the soil (saturated soil moisture content 30%), the mechanical reinforcement form the L. bicolor root maintains some degree of stability. Shrubs have a good effect on enhancing the stability of slopes, especially in areas prone to shallow landslides.

The development of robust analytical tools capable of probing the formation kinetics and thermodynamics of DNA nanostructures is a crucial step toward better understanding and manufacturing of diverse DNA-based materials. Herein, we introduce a real-time fluorescence anisotropy assay and rationally designed DNA reaction termination probes (DRTPs) as a set of new tools for exploring the formation mechanisms of DNA nanostructures. We deployed these tools for probing the formation of a classic tetrahedral DNA nanostructure (TDN) as a model system. Our tools revealed that the formation of TDN was dominated by simultaneous hybridization, whereas its undesired side products were caused mainly through step-wise hybridization. An optimal reaction temperature exists that favors the formation of TDN over side products. With insight into the TDN formation mechanism, we further engineered magnetic DRTPs to achieve single-step purification of TDN, enabling 10-fold improvement in the ratio between the targeted TDN and undesired side products without tedious procedures or bulky instruments. Combining the optimal reaction and purification conditions, we finally demonstrated the one-pot synthesis and purification of TDN. The analytical techniques offered in this work may hold potential to find wide applications and inspire new analytical methods for structural DNA nanotechnology.

Fascinating phenomena can occur as charge and/or energy carriers are confined in one dimension1–4. One such example is the divergent thermal conductivity (κ) of one-dimensional lattices, even in the presence of anharmonic interatomic interactions—a direct consequence of the Fermi–Pasta–Ulam–Tsingou paradox proposed in 19555. This length dependence of κ, also known as superdiffusive phonon transport, presents a classical anomaly of continued interest6–9. So far the concept has remained purely theoretical, because isolated single atomic chains of sufficient length have been experimentally unattainable. Here we report on the observation of a length-dependent κ extending over 42.5 µm at room temperature for ultrathin van der Waals crystal NbSe3 nanowires. We found that κ follows a 1/3 power law with wire length, which provides experimental evidence pointing towards superdiffusive phonon transport. Contrary to the classical size effect due to phonon-boundary scattering, the observed κ shows a 25-fold enhancement as the characteristic size of the nanowires decreases from 26 to 6.8 nm while displaying a normal–superdiffusive transition. Our analysis indicates that these intriguing observations stem from the transport of one-dimensional phonons excited as a result of elastic stiffening with a fivefold enhancement of Young’s modulus. The persistent divergent trend of the observed thermal conductivity with sample length reveals a real possibility of creating novel van der Waals crystal-based thermal superconductors with κ values higher than those of any known materials. A 1/3 power law between thermal conductivity and length of a NbSe3 nanowire is observed, pointing towards a superdiffusive heat transport regime.

For the inverted organic solar cells (OSCs), the interface contacts between the ZnO electron transporting layer and the organic active layer play an important role in the device performance and stability. Since the solution-processed ZnO surface always contains some base or zinc salt contaminants, we explored how the surface pH conditions influence the performance and stability of the nonfullerene acceptor (NFA) cells. A tight relationship between the surface pH condition and the device performance and stability was established. Specifically, device performance and stability were improved by treating the ZnO films with acid solutions but worsened after base treatment. The large number of hydroxyl groups on the surface of the solution-processed ZnO films was proved to be the main reason for the surface pH condition-related performance, which caused oxygen-deficient defects and unfavorable vertical phase separation in the blend films, hindered the photogenerated charge transfer and collection, and consequently resulted in low short-circuit current density and power conversion efficiency (PCE). The surface -OH groups also boosted the photocatalytic activity and led to fast degradation of the nonfullerene acceptor. Removal of the surface -OH groups can alleviate such problems. Different acid solutions, ZrAcac, 2-phenylethylmercaptan (PET), and glutamic acid (GC), were used to treat the ZnO films, and PET treatment was the most effective treatment for performance improvement. An efficiency of 16.46% was achieved for the PM6:Y6 cells and the long-term stability under continuous illumination conditions was significantly improved with a T80 lifetime of over 4000 h (4410 h), showing the excellent long-term stability of this heterojunction solar cell. Our understanding of the surface pH condition-related device performance and stability would guide the development of a feasible method for solving the interface problems in OSCs. We also provide a practical strategy to modify ZnO with acid solutions for high-performance and stable NFA OSCs.

Iron carbodiimide (FeNCN) belongs to a type of metal compounds with a more covalent bonding structure compared to common transition metal oxides. It could provide possibilities for various structural designs with improved charge-transfer kinetics in battery systems. Moreover, these possibilities are still highly expected for promoting enhancement in rate performance of sodium (Na)-ion battery. Herein, oriented FeNCN crystallites were grown on the carbon-based substrate with exposed {010} faces along the [001] direction (O-FeNCN/S). It provides a high Na-ion storage capacity with excellent rate capability (680 mAh g-1 at 0.2 A g-1 and 360 mAh g-1 at 20 A g-1), presenting rapid charge-transfer kinetics with high contribution of pseudocapacitance during a typical conversion reaction. This high rate performance is attributed to the oriented morphology of FeNCN crystallites. Its orientation along [001] maintains preferred Na-ion diffusion along the two directions in the entire morphology of O-FeNCN/S, supporting fast Na-ion storage kinetics during the charge/discharge process. This study could provide ideas toward the understanding of the rational structural design of metal carbodiimides for attaining high electrochemical performance in future.

Urban growth can take different forms, such as infill, expansion and leapfrog development. Here we focus on leapfrogging, which is characterised as new urban development bypassing vacant land. Analysing a sample of 100 global locations, we study the probability that land cover is converted from non-urban to urban as a function of the minimum distance to existing urban cells. The probability decreases with the distance but in many of the considered real-world samples it increases again just before the maximum possible distance. Comparing these empirical findings with numerical ones from a gravitational model, we discover that the characteristic increase can be found in both. Our results indicate that the conversion probability as a function of the distance to urban land cover includes three urban growth domains. (i) Expansion of existing settlements, (ii) discontinuous development of coincidental new settlements rather close to existing ones and (iii) leapfrogging of new settlements far away from existing ones. We conclude that gravitational effects can explain discontinuous development but leapfrogging can be attributed to a scarcity of developable land at long distances to settlements.