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[Objective] The engineering disturbances have triggered soil erosion events in subalpine meadows, intensify regional soil erosion and vegetation destruction. The relationship between physical and chemical properties and disintegration characteristics of subalpine meadow soils in central Yunnan was studied to provide reference for soil and water conservation and control and vegetation protection in sub-alpine meadow ecosystems. [Methods] By X-ray diffraction, electron microscopy scanning, and static water disintegration experiments were conducted to determine the physico-chemical properties, mineral composition, microscopic structure, and disintegration characteristics of subalpine meadow soils in central Yunnan. The correlation between soil disintegration and physico-chemical properties was analyzed to explore the reason of soil disintegration in sub-alpine meadows of central Yunnan. [Results] (1) The subalpine meadow soils in central Yunnan exhibited a high susceptibility to disintegration when encountering water. The resistance to disintegration of different parent materials in the same soil layer were as follows sandstone>limestone≈basalt. The characteristics of different soil layers in the same parent material were as follows leaching horizon>deposition layer>parent material layer. (2) Correlation analysis showed that the average soil disintegration rate was significantly negative correlated with organic matter (r=-0.84) and total nitrogen (r=-0.83), positively correlated with clay content (r=0.88), and positively correlated with montmorillonite (r=0.68) and hematite (r=0.77). (3) The main factors affecting the disintegration of subalpine meadow soils in central Yunnan were biological processes and swelling of hydrophilic clay minerals such as montmorillonite and illite. [Conclusion] The resistance to disintegration of subalpine meadow soils in central Yunnan was ranked as follows: Sandstone>limestone≈basalt for different parent materials, and leaching horizon>deposition layer>parent material layer for different soil layers. The subalpine meadow soil in central Yunnan was easy to disintegrate when exposed to water, the main factors affecting the disintegration of subalpine meadow soils in central Yunnan were biological processes and swelling of hydrophilic clay minerals such as montmorillonite and illite.

[Objective] In order to investigate the mechanism of mechanical effect of root-soil complex and the application of modeling method. [Methods] The concept and connotation of root-soil complex, the principle of mechanical effect and mechanical model of root-soil complex, advantages and disadvantages as well as the scope of application were summarized and analyzed by using literature analysis method and comparative analysis method. [Results] (1) The root-soil complex was a composite whole of mechanical coupling effect between root system and soil body, and the root system was intertwined in soil playing a reinforced role. (2) The mechanical relationship between root system and soil body was essentially the result of soil mechanical, hydraulic and composite mechanical properties of root-soil complex. The soil mechanical and hydraulic properties focused on the influence of roots on the soil and the influence of water on the soil and root system respectively, and the composite mechanical properties focused on the direct influence of soil properties on the properties and structure of plant roots, so that the mechanical relationship between roots and soil was in a dynamic balance through the three. (3) The study of the composite mechanical model of the root-soil complex was slightly less than that of the soil mechanical and hydraulic model, which were based on quantitative parameters and measure the soil consolidation effect by comparing parameters. However, the composite mechanical properties involves both soil and hydraulic properties, which was a comprehensive consideration and should be the key research direction in the future. [Conclusion] In-depth research was needed in the future to investigate the effects of freeze-thaw cycle, dry-wet alternation and dry-hot cycle on root and soil interaction in different regions, the shear strength of multi-type plant mixtures, the influence mechanism of chemical and microbial effects on soil-water propertiess and the construction of composite models need to be further studied. This study can provide important theoretical value and engineering reference for vegetation restoration, soil and water conservation and sustainable development in ecologically fragile areas.

【Objective】 Amending degraded soils with soil conditioners is a technique widely used to improve soil quality. Different conditioners are commercially available but their effect on soil release curve is less understood. The purpose of this paper is to compare change in water characteristic curves of a red loam soils amended using different soil modifiers. 【Method】 The soil was amended by glutinous rice gum, wood fiber, and their mixture at different ratios. We measured the change in matrix suction (ψ) and volumetric soil water content (θv) of each soil sample. The internal friction angle (φ) of the soil at saturation was determined using the direct shear test method, from which we calculated the adsorption strength (τψ) of the soil using the Fredlund double stress variable shear strength. 【Result】 ① Glutinous rice gum and wood fiber both increased the saturated soil water content (θs), while their mixture reduced θs. Glutinous rice gum and its mixture with wood fiber reduced the residual soil water content (θr), while the wood fiber working alone only reduced the residual water content when the amendment ratio was low or high. All three modifiers increased the air-entry value (ψa), with the increase ranked in the order of the mixture > glutinous rice gum > wood fiber. Glutinous rice gum reduced the residual matric potential (ψr), while the wood fiber increased ψr, with the mixture in the between with its ψr higher than that of the non-amended soil. The matric potential decreased fastest as soil water content increased in the glutinous rice gum treatment, followed by the mixture and wood fiber. ②All conditioners increased the adsorption strength τψ, and the shear strength decreased with the increase in ψ. For soil water content in the range of 23.73%~30.76%, amending the soil with 2.5%~5.0% of wood fiber gave the highest adsorption strength, followed by non-amended soil, the amendment by 2.5%~5.0% of mixture, and the amendment by 0.5%~5.0% of glutinous rice gum. 【Conclusion】 ①Glutinous rice gum mainly reduced the ability of the soil to hold water. Wood fiber influenced θs, θr and ψr most and improved the ability of the soil to hold water. The mixture of wood fiber and glutinous rice gum increased ψa most, improving the ability of soil to hold water in the wet-end, but reduced water-holding capacity of the soil in the middle range. ②The effect of different modifiers in increasing τψ is ranked in the order of wood fiber > glutinous rice gum > their mixture.

[Objective] Soil disintegration characteristics around the Huangdeng hydropower station reservoir on the Lancang River were studied in order to provide a basis for the prevention and control of soil erosion around the reservoir, reduce the sediment entering the reservoir, and provide a reference for soil and water conservation and ecological restoration in the Three Rivers parallel flow area. [Methods] We used a combination of field survey sampling and laboratory experiments to determine the disintegration rate and physicochemical properties of five typical soils around the reservoir, and to analyze the correlation between soil disintegration rate and soil properties. [Results] Soil disintegration (ranging from strong to weak) was observed to follow the order of red soil, yellow brown soil, siltation soil (top), siltation soil (bottom), and purple soil. Under the saturated soil condition, the ratio of average disintegration rates was 8.76∶5.65∶5.24∶4.29∶1. Soil disintegration was closely related to the soil liquid plastic limit, mechanical composition, porosity, and other properties; There was a significant negative correlation between the average soil disintegration rate and both soil silt and liquid plastic limit. A significant positive correlation was observed between soil disintegration rate and both the content of soil coarse sand and porosity. When the initial moisture content (ω0) was high, soil disintegration rate was significantly negatively correlated with soil organic matter, hydrolytic nitrogen, available phosphorus, and total nitrogen. The linear equations between soil disintegration rate and total nitrogen, silt, and liquid plastic limit for the five soil types in the saturated state had a high fit degree (R2>0.9). [Conclusion] When ω0 was saturated for red soil, yellow brown soil, siltation soil, and purple soil, soil total nitrogen content, silt content, and liquid plastic limit can be used to predict soil disintegration. Forests and grasslands should be established and maintained or engineering measures should be implemented to treat the red soil and yellow brown soil around Huangdeng power station reservoir. Suitable water-zone plants should be planted on siltation soil. Measures should be taken to strengthen the protection of purple soil so that it is suitable for agriculture and forests. Taking these measures will provide more agricultural and forestry land resources for rural revitalization in the reservoir area.

【Objective】 Drought is the most important abiotic stress facing agricultural management and economic development in many regions and countries. The aim of this paper is to identify the spatiotemporal variation of drought in Yunnan Province, using the standardized precipitation index (SPI). 【Method】 Meteorological data measured over the past 31 years from 36 meteorological stations across the province were used in the analysis. Multi-scale variations of the droughts in both time and space were calculated using SPI, GIS, nonparametric Mann-Kendall trend test and other methods. 【Result】 ①Both annual and seasonal SPI fluctuated temporally, but we identified a small annual increase in spring SPI, small annual decreases in summer, autumn and winter SPI. The autumn SPI varied mostly, and the winter SPI least. The annual SPI varied from -1.95 to 1.44. ②The annual drought frequency varied from 32.26% to 50.00%, with the severity of most droughts varying from mild to extreme range. Spatially, drought occurred more frequently in Wenshan, Honghe, Kunming, Chuxiong and Dehong than in other regions in the province. ③Seasonally, drought frequency in spring, summer, autumn and winter was 39.86%, 39.83%, 38.43%, and 41.33%, respectively. Although drought frequency in different seasons was close, their severity differed considerably. ④Annually, except for five meteorological stations which found increased drought frequency, drought frequency in other stations remained statistically the same. Seasonally, most stations showed decreased drought frequency in spring, eleven stations showed increased drought frequency in summer, and six and two stations showed increased autumn droughts and winter droughts, respectively. 【Conclusion】 Annual and seasonal drought frequency is spatially heterogeneous across the province. Droughts in the province are seasonal, with droughts occurring in spring and winter more frequently and severely.

Wind loads have become one of the key influencing factors for the running safety of vehicles and comfort of passengers. The investigation of the wind speed spectrum characteristics of a moving vehicle under turbulent crosswinds is of great importance. Expressions of the wind speed spectrum of a moving vehicle were obtained from the von Kármán spectrum, based on Taylor's frozen flow hypothesis. The influencing factors, including the ratio of the vehicle speed to the wind speed and wind yaw angles, were analyzed. The change rules of the wind speed spectrum peak and its corresponding frequency were also studied. The results show that the wind speed spectrum peak values of the moving vehicle were larger than those of the static vehicle. The wind speed spectrum peak values corresponding to the moving vehicle were first increased and then decreased, as the wind yaw angles increased. Some of the frequencies corresponding to the longitudinal wind speed spectrum values of the moving vehicle were smaller than those of the static vehicle. Therefore, the energy had been transferred to the lower frequency. For the moving vehicle, the frequency values corresponding to the longitudinal wind speed spectrum peak were first increased and then decreased, as the ratio of the vehicle speed to the wind speed and the wind yaw angle increased. [ABSTRACT FROM AUTHOR]

To investigate the vortex-induced vibration (VIV) characteristics of a narrow-streamlined railway box girder and optimize its VIV performance, a long-span railway cable-stayed bridge was analyzed. Based on sectional model wind tunnel tests, the influence of the wind attack angle and the damping ratio on the VIV performance of the girder was investigated. The main inducing factors of the VIV of the narrow railway box girder were explored and a series of corresponding optimization schemes was put forward. The results show that there is no VIV when the wind attack angles are −5°, −3° and 0°, and the damping ratio is 0.2%. The non-dimensional maximum amplitudes 1000 y / D of the girder at wind attack angles of +3° and +5° are 14.4 and 19.4, respectively. The maximum amplitudes decrease with the increase of the damping ratios. The railing base is the influence factor that induces the vertical VIV, because the separation vortices between the railing base and ballast wall, as well as behind the railings, cause the VIV of the railway steel box girder. Compared with that of the girder section with the ballastless track board, the non-dimensional maximum vertical VIV amplitude of the girder without the ballastless track board greatly increases from 19.4 to 63.5, which could effectively suppress the VIV of the main girder. Lastly, in the construction state, vertical VIV occurs for girder sections I and II, which have respective aspect ratios of 4.3 and 4.6, at wind attack angles of +3° and +5°. Girder section III, which has a 6.7 aspect ratio and is more streamlined, does not have a VIV. The greater the aspect ratio of the bridge girder, the better the VIV performance. The relevant results could serve as a guide for wind resistance design of railway streamlined box girders. [ABSTRACT FROM AUTHOR]

Two modes of the atmospheric-pressure plasma discharge, distinguished by the dominant O3 and NO x species are studied numerically and experimentally. To investigate the mode transition mechanisms, here we develop a global chemical kinetics model for the atmospheric-pressure dielectric barrier discharge involving 63 species and 750 reactions. Validated by the experimental results, the model accurately describes the mode transition. The N, O, O2(a), and O2(b) are the essential transient intermediate species for the O3 and NO x production and loss reactions. The individual and synergistic effects of the specific discharge energy and the gas temperature on the species density and the relative contributions of the dominant reactions are quantified under the increasing discharge voltage conditions. The modeling results indicate that the gas temperature and specific discharge energy both contributed to the discharge mode transition, while the decisive factors affecting the change of the O3 and NO x density are different in the respective modes. These insights contribute to diverse plasma applications in biomedicine, agriculture, food, and other fields where selective and controlled production of O3 and NO x species is the key for the desired plasma performance. [ABSTRACT FROM AUTHOR]

In this paper, we consider perturbation properties of a linear second-order conic optimization problem and its Lagrange dual in which all parameters in the problem are perturbed. We prove the upper semi-continuity of solution mappings for the pertured problem and its Lagrange dual problem. We demonstrate that the optimal value function can be expressed as a min-max optimization problem over two compact convex sets, and it is proven as a Lipschitz continuous function and Hadamard directionally differentiable. [ABSTRACT FROM AUTHOR]

In this paper, we consider a class of nonsmooth and nonconvex optimization problem with an abstract constraint. We propose an augmented Lagrangian method for solving the problem and construct global convergence under a weakly nonsmooth Mangasarian-Fromovitz constraint qualification. We show that any accumulation point of the iteration sequence generated by the algorithm is a feasible point which satisfies the first order necessary optimality condition provided that the penalty parameters are bounded and the upper bound of the augmented Lagrangian functions along the approximated solution sequence exists. Numerical experiments show that the algorithm is efficient for obtaining stationary points of general nonsmooth and nonconvex optimization problems, including the bilevel program which will never satisfy the nonsmooth Mangasarian-Fromovitz constraint qualification. [ABSTRACT FROM AUTHOR]

Creating haptic interface by glove-based wearable robotic system has become an increasingly interested topic in the area of human robotic interaction. Many force feedback gloves are constructed based on soft actuators. However, the recent development of haptic and force feedback technology mainly focused on the advancement of the actuating components and mechanism, and innovation of the force feedback rendering algorithms. It seems that another important part of this human-robot-interaction loop, i.e. the human factors, were understudied. Here, this study focused on the learning effect in haptic perception. We designed a pneumatic muscle-based force feedback robotic glove which can provide customized force feedback to the dorsal surface of each finger. An experiment was carried out with a specifically training procedure and evaluation on the force feedback perceptions. The results show that practice-induced improvement can be achieved by this training, allowing people have a better perception of the force feedback provided by this glove.

Creating a digital twin has enormous potential in biomedical engineering. However, it is also technically challenging. No existing system can allow people who don't have the art-and-design background to create their own digital twin. To fill this gap, this study proposes a low-cost wearable system and a user-friendly framework for creating personalized digital twins with a fast speed and high fidelity. The personalized human digital twin can capture synchronized facial expressions, gaze direction, and whole-body movements for real-time rendering. The system simplifies the complex process of creating digital humans, and allows for the creation of data-driven characters without specialized skills.Clinical Relevance- This system can be used to help doctors keep track record of the patient's health status in a more visual and realistic way, supporting them in making more accurate clinical decisions, and facilitating a more detailed medical intervention.