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In situ TEM dynamic observation of non-classical nucleation at heterogeneous interfaces further enriches the nucleation theory.

：The reservoir-bank collapse has caused soil erosion and bank expansion in the lower Yellow River, which seriously affects the ecological environment and agricultural development. Understanding the processes of mass movement occurred on reservoir-bank is important to predict and control bank expansion. However, little research exists concerning how to accurately quantify the process of bank collapse and trace the source of sediment. In this study, a reservoir-bank model with the gentle slope of 3°, steep slope of 40° and abrupt slope of 70°, was constructed according to geomorphological characteristics of the soil reservoir-bank in Xiaolangdi Reservoir, in which rare earth elements were used to trace the provenance of sediment originated from mass movement on reservoir-bank under different rainfall conditions, and quantify the soil loss from the bank contributed to sediment deposition in reservoir. The results show that the sediment in reservoir mainly comes from steep slope, and the percentage contribution of abrupt slope to the total soil loss increases significantly in rainstorms with the precipitation larger than 60 mm. Under the rainstorms, the contributions of the gentle slope, steep slope and abrupt slope to soil loss were 10%, 55% and 35%, respectively. Without rainstorm, the contributions of the gentle slope, steep slope, and abrupt slope to soil loss were 4%, 72% and 24%, respectively. Meanwhile, sediment deposition in reservoir also mainly derived from steep slope and abrupt slope. The contribution of steep slope and abrupt slope to sediment deposition were 49% and 40% under the rainstorms, and the contribution of steep slope and abrupt slope to sediment deposition without rainfall were 67% and 28%, respectively. In addition, most of the sediment generated from the lower abrupt slope accumulates near the reservoir-bank, while the sediment generated from the steep slope accumulates at a distance from the reservoir-bank. Under the rainstorms, the contribution of upper steep slope to sediment deposition was 54% at 240 cm from the reservoir-bank, while the contribution of lower steep slope to sediment deposition without rainfall was 70% at 180 cm from the reservoir-bank. Whether with or without rainfall, the contribution of lower abrupt slope to sediment deposition was all about 54% at 40 cm from the reservoir-bank. Thus, in the near future, engineering measures such as grid protected slope may be used in the reservoir area to protect the steep slope of reservoir-bank, which can effectively reduce soil erosion and bank expansion in the reservoir area.Keywords: Bank collapse; Mass movement; Xiaolangdi Reservoir; REEs; Rainstorm

Through in-situ TEM observation during 30 keV H2+-He+ dual-beam irradiation at 723 K, the reaction and transformation of dislocation loops in pure Mo were investigated, especially for loops. Irradiation could directly cause the formation of 1/2 loops and loops, but 1/2 loops were dominant. In-situ observation confirmed the formation mechanism of loops, including direct irradiation induced mechanism, 1/2 loop direct conversion mechanism, and reaction mechanism of two 1/2 loops. Meanwhile, the reaction of two 1/2 loops to produce loop should not require the strict size similarity condition. The reaction between 1/2 loops could also produce 1/2 loop, which was essentially a process in which one loop absorbed another one. The yield strength increment caused by irradiation-induced loops was analyzed, and its saturation value reached 0.48 GPa at 0.06 dpa. Compared with single He+ irradiation, the number density and average diameter of loops increased significantly and more serious damage was caused under the synergistic effect of hydrogen and helium. The mechanism based on in-situ experimental observation was discussed in depth.

The microstructural evolution of purity Pd under 30 keV He+ irradiation at 573 K was investigated by in-situ transmission electron microscopy. The nucleation, growth, merging, annihilation, size change, number density variation, and types of dislocation loops were analyzed under the influence of irradiation fluence and sample thickness. Both perfect dislocation loops with b = 1/2 and faulted dislocation loops with b = 1/3 were formed. However, at low irradiation fluence, most of the loops were 1/3 loops. The thickness of TEM foil obviously affected the ratio of 1/3 loop variants, the size and number density of dislocation loops, and the characteristics of bubble-loop complexes. With the increase of irradiation fluence, the size of dislocation loops increased, but loop volume number density remained almost constant until dislocation loops merged and evolved into dislocation network. There was an obvious interaction between dislocation loops and bubbles, indicating that 1/3 loop was first formed at the initial stage of irradiation, and when the loop grew to a certain size, obvious helium bubbles appeared inside its region.

The effects of long-term natural climate change and human activities on runoff generation mechanism in the middle Yellow River Basin are long-standing concerns. This study analyzed the characteristics of hydro-climatic variables in the meso-scale Tuweihe catchment based on the observed data for the period 1956–2016 and a climate elastic method. The spatial distribution of dominant runoff processes (DRP) following land use changes in case of rainfall was identified. The results show significant decreasing trends in annual runoff, whereas slightly downward trends are identified for annual precipitation and potential evapotranspiration, 1984 is detected as the mutation year of the study period. The average contributions of climate change and human activities to the runoff reduction in the Tuweihe catchment were 33.2% and 66.8%, respectively. In general, the influences of human activities on runoff are applied mostly through the alteration of the catchment characteristics. The dominant runoff processes changes between 1980 and 2015 show significant effects of large-scale soil and water conservation measures in the Tuweihe catchment. We found that Hortonian overland flow (HOF) and fast subsurface flow (SSF1) were the two main processes in 1980 (30.3% and 34.4% respectively), but the proportion of HOF decreased by 9.6% in 2015. The proportions of saturation overland flow (SOF) and SSF have increased to varying degrees, which means that the catchment is more prone to generate subsurface flow processes. Consequently, under similar rainfall conditions, the runoff yield of flood events decreases in the second period. HIGHLIGHTS Based on GIS to identify the spatial distribution map of the dominant runoff process in the watershed, it can be used as a starting point for the construction of a refined hydrological model in the future.; Attribution analysis of the covariant phenomenon of the runoff law of storms and floods under changing conditions from the mechanism level.

Dislocation loop and gas bubble evolution in tungsten were in-situ investigated under 30 keV H2+ and He+ dual-beam irradiation at 973 K and 1173 K. The average size and number density of dislocation loops and gas bubbles were obtained as a function of irradiation dose. The quantitative calculation and analysis of the migration distance of 1/2 $$\langle{111}\rangle$$ loops at low irradiation dose indicated that the main mechanism of the formation of $$\langle{100}\rangle$$ loops should be attributed to the high-density helium cluster inducement mechanism, instead of the 1/2 $$\langle{111}\rangle$$ loop reaction mechanism. H2+ and He+ dual-beam irradiation induced the formation of $$\langle{100}\rangle$$ loops and 1/2 $$\langle{111}\rangle$$ loops, while increasing the irradiation temperature would increase $$\langle{100}\rangle$$ loop percentage. The percentage of $$\langle{100}\rangle$$ loops was approximately 18.6% at 973 K and increased to 22.9% at 1173 K. The loop reaction between two 1/2 $$\langle{111}\rangle$$ loops to form a large-sized 1/2 $$\langle{111}\rangle$$ loop was in-situ observed, which induced not only the decrease of the number of 1/2 $$\langle{111}\rangle$$ loops but also the significant increase of their sizes. The $$\langle{100}\rangle$$ loops impeded the movement of dislocation line and tended to escape from it instead of being absorbed. With the increase of irradiation dose, the yield strength increment ( $$\Delta {\sigma }_{\mathrm{l}\mathrm{o}\mathrm{o}\mathrm{p}}$$ ) caused by the change of loop size and density increased first and then decreased slightly, while the yield strength increment ( $$\Delta {\sigma }_{\mathrm{b}\mathrm{u}\mathrm{b}\mathrm{b}\mathrm{l}\mathrm{e}}$$ ) caused by the change of bubble size and density always increased. Meanwhile, within the current irradiation dose range, $$\Delta {\sigma }_{\mathrm{l}\mathrm{o}\mathrm{o}\mathrm{p}}$$ was much larger than $$\Delta {\sigma }_{\mathrm{b}\mathrm{u}\mathrm{b}\mathrm{b}\mathrm{l}\mathrm{e}}$$ .

The changes of runoff in the middle reaches of the Yellow River basin of China have received considerable attention owing to their sharply decline during recent decades. In this paper, the impacts of rainfall characteristics and land use and cover change on water yields in the Jingle sub-basin of the middle reaches of the Yellow River basin were investigated using a combination of statistical analysis and hydrological simulations. The Levenberg Marquardt and Analysis of Variance methods were used to construct multivariate, nonlinear, model equations between runoff coefficient and rainfall intensity and vegetation coverage. The land use changes from 1971 to 2017 were ascertained using transition matrix analysis. The impact of land use on water yields was estimated using the M-EIES hydrological model. The results show that the runoff during flood season (July to September) decreased significantly after 2000, whereas slightly decreasing trend was detected for precipitation. Furthermore, there were increase in short, intense, rainfall events after 2000 and this rainfall events were more conducive to flood generation. The “Grain for Green” project was carried out in 1999, and the land use in the middle reaches of the Yellow River improved significantly, which make the vegetation coverage (Vc ) of the Jingle sub-basin increased by 13%. When Vc approaches 48%, the runoff coefficient decreased to the lowest, and the vegetation conditions have the greatest effect on reducing runoff. Both land use and climate can change the water yield in the basin, but for areas where land use has significantly improved, the impact of land use change on water yield plays a dominant role. The results acquired in this study provide a useful reference for water resources planning and soil and water conservation in the erodible areas of the middle reaches of the Yellow River basin.

Photothermal/photodynamic therapy (PTT/PDT) and synergistic therapeutic strategies are often sought after, owing to their low side effects and minimal invasiveness compared to chemotherapy and surgical treatments. However, in spite of the development of the most PTT/PDT materials with good tumor-inhibitory effect, there are some disadvantages of photosensitizers and photothermal agents, such as low stability and low photonic efficiency, which greatly limit their further application. Therefore, in this study, a novel bismuth-based hetero-core-shell semiconductor nanomaterial BiNS-Fe@Fe with good photonic stability and synergistic theranostic functions was designed. On the one hand, BiNS-Fe@Fe with a high atomic number exhibits good X-ray absorption, enhanced magnetic resonance (MR) T2-weighted imaging, and strong photoacoustic imaging (PAI) signals. In addition, the hetero-core-shell provides a strong barrier to decline the recombination of electron-hole pairs, inducing the generation of a large amount of reactive oxygen species (ROS) when irradiated with visible-NIR light. Meanwhile, a Fenton reaction can further increase ROS generation in the tumor microenvironment. Furthermore, an outstanding chemodynamic therapeutic potential was determined for this material. In particular, a high photothermal conversion efficiency (η = 37.9%) is of significance and could be achieved by manipulating surface decoration with Fe, which results in tumor ablation. In summary, BiNS-Fe@Fe could achieve remarkable utilization of ROS, high photothermal conversion law, and good chemodynamic activity, which highlight the multimodal theranostic potential strategies of tumors, providing a potential viewpoint for theranostic applications of tumors.

To investigate the potential benefits of acarbose therapy on cardiovascular events (CVD) in Type 2 diabetes (T2DM) in an urban community over 10-year follow-up. The study population of Beijing Community Diabetes Study (BCDS) were type 2 diabetes (T2DM) living in 21 communities in Beijing. All patients received comprehensive intervention in accordance with the Chinese guidelines for the prevention and treatment of diabetes. Professors in endocrinology from top tier hospitals regularly visited the communities for consultations, which was a feature of this study. A total of 1797 T2DM in BCDS study had complete screening data, including blood glucose, blood pressure, lipid profiles and acarbose continuous therapy. After 10-year follow-up, the risks of CVD outcomes were assessed according to whether patients had received acarbose therapy or not. All patients were followed-up to assess the long-term effects of the multifactorial interventions. At baseline, compared with the acarbose therapy free in T2DM, there was no significant difference in achieving the joint target control in patients with acarbose therapy. From the beginning of 8th year follow-up, the joint target control rate in patients with acarbose therapy was significantly higher than that of acarbose therapy free. During the 10-year follow-up, a total of 446 endpoint events occurred, including all-cause death, cardiovascular events, cerebrovascular events. The incidences of myocardial infarction (from the 4th year of follow-up) and all-cause death (from the 2nd year of follow-up) in patients who received acarbose therapy were significantly lower than that of acarbose therapy free respectively. In Cox multivariate analyses, there were significant differences in incidences of myocardial infarction and all-cause death between afore two groups during the 10-year follow-up, and the adjusted HRs were 0.50 and 0.52, respectively. After multifactorial interventions, T2DM with acarbose therapy revealed significant reductions of myocardial infarction and all-cause death. The long-term effects of with acarbose therapy on improving joint target control might be one of the main reasons of myocardial infarction and all-cause death reduction.Trial Registration: ChiCTR-TRC-13003978, ChiCTR-OOC-15006090.

In-situ TEM observation and molecular dynamics simulation were used to investigate the evolution of irradiation-induced dislocation loops and their interactions with the pre-existing dislocation lines in molybdenum irradiated by 30 keV He+ at 673 K. The nucleation, annihilation, merging, size change, and types of dislocation loops were investigated in detail, and the hardening effect from dislocation loops was analyzed. With the increase of helium fluence, the volume number density of dislocation loops increased rapidly and then decreased slowly to a saturation value, while the average size of dislocation loops increased continuously until it reached an upper limit. Both 1/2 and loops were formed, with a proportion of 60.2% to 39.8% at 3.95 × 1015 He+.cm−2 (0.07 dpa). The pre-existing dislocation lines would suppress the nucleation and growth of the dislocation loops, while the irradiation-induced dislocation loops had a strong pinning effect on the dislocation lines and impeded their motion. Molecular dynamics simulations were used to clarify the atomistic mechanisms of some major features of the line-loop interactions observed in the in-situ experiment, which showed in a good agreement. The different interaction processes depended on the Burgers vector and plane of the dislocation loop, the motion and reaction kinetics of dislocation segments, and the external loading.

The megacities in China experienced increasing impacts from the urban floods due to the climate change in the past ten years. However, it is still unknown how to deal with the potential hazards under the impact of extreme precipitation. This paper briefly reviews the general characteristics and challenges of urban flooding in China with a case study of the extreme rainstorm in Zhengzhou on 20 July 2021. Results indicate that, to comprehensively protect a megacity with existing building standards and emergency plans is difficult under the extreme rainstorms, and the disruption of weak lifeline facilities, e.g. the road network, may further disrupt the provisions from neighbouring cities. This study offers a unique perspective reflecting a multi-scale approach from a single local city to regional area, an urban cluster or even a country on the urban floods control, urban infrastructure design and policy development. In more details, the measures are anticipated to increase the control rate of annual rainfall via the development of sponge city, improve monitoring and forecasting in the urban area, and enhance the risk-response strategies from the local government. The study strongly suggests expand the experiences and achievements of the flood management from a disaster area to adjacent or distant cities coupled with different pathways including government cooperation, water conservation practices, information exchange or human migration. The policymakers in a megacity are also encouraged to update the viewpoints for the policies and strategies to control floods. Hopefully a clue for relatively effective water management and land use for the sustainable urban development may be obtained from the study.

In this study, novel Al-based Gd2O3 metal matrix composites were designed and synthesized using powder metallurgy to overcome the shortcomings of common neutron absorbers used as shielding materials in spent fuel storage. With an increase in the ball-milling time, the size of powder particles was gradually refined to nanometer scale. Meanwhile, monoclinic Gd2O3 was induced by collision pressure and, according to dynamic analysis, the solid solution was inconspicuous. Al3Gd and Gd3Al5O12 were formed during ball-milling, which was further accelerated during sintering because thermodynamics analysis indicated that the reaction was endothermic. The microstructures of powder mixtures and sintered bulks were seen. Particles of various shapes were found to be dispersed in the bulk matrix; their shapes and sizes varied with milling time, sintering time and temperature, and concentration of Gd2O3. With the increase in sintering temperature and time, the number of porosities and nanoparticles were found to decrease, whereas the sizes of the particles increased. The microhardness of the samples prepared under various conditions was measured, and its relationship with the microstructure was analyzed. It was found that microhardness was positively correlated with the areas of the particles, whereas it was negatively correlated with their sizes. Further, the thermal parameters of the sintered bulks were also measured and the effect of their microstructure and components was analyzed.

To overcome the disadvantages of commercial neutron absorbers used for spent-fuel storage, novel Al-based Gd2O3–W composites were designed by calculating the neutron absorption and γ-ray transmission and synthesized via ball milling, cold isostatic pressing, and sintering. During the ball milling, the cubic Gd2O3 was partially transformed into monoclinic Gd2O3, and new Al3Gd and Gd3Al5O12 phases were formed. The sintering induced chemical reactions that formed Gd3Al5O12, Al3Gd, and Al12W phases. Nanoparticles with sizes of 100–300 nm were uniformly distributed in the sintered bulk materials. Moreover, with increasing sintering time, sintering temperature, and W content, the microhardness of the Al-based Gd2O3–W metal matrix composites (MMCs) increased. The compressive strength of the Al-based Gd2O3–W MMCs increased with W content, in contrast to the thermal expansion coefficient. Overall, the properties of the synthesized composites were better than those of the reference Al–B4C.