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Aboveground biomass is an important indicator used to characterize the growth status of crops, as well as an important physical and chemical parameter in agroecosystems. Aboveground biomass is an important basis for formulating management measures such as fertilization and irrigation. We selected four irrigated wheat fields in a region near Kaifeng, Henan Province, for this study. The terrain in that region was undulating and had spatial differences. We used a low-altitude unmanned aerial vehicle (UAV) remote sensing platform equipped with a multispectral camera, thermal infrared camera, and RGB camera to simultaneously obtain different remote sensing parameters during the key growth stages of wheat. Based on the extracted spectral reflectivity, thermal infrared temperature, and digital elevation information, we calculated the spatial variability of remote sensing parameters and growth indices under different terrain characteristics. We also analyzed the correlations between vegetation indices, temperature parameters, structural topographic parameters and aboveground biomass. Three machine learning methods were used, including the multiple linear regression method (MLR), partial least squares regression method (PLSR) and random forest regression method (RFR). We compared the aboveground biomass (AGB) estimation capability of single-modal data versus multimodal data fusion frameworks. The results showed that slope was an important factor affecting crop growth and aboveground biomass. We therefore analyzed several remote sensing parameters for three different slope scales. We found significant differences among them for soil water content, water content of plants, and aboveground biomass at four growth stages. Based on the strength of their correlation with aboveground biomass, seven vegetation indices (NDVI, GNDVI, NDRE, MSR, OSAVI, SAVI, and MCARI), four canopy structure parameters (CH, VF, CVM, SLOPE) and two temperature parameters (NRCT, CTD) were selected as the final input variables for the model. There was some variability in the accuracy of the models at different growth stages. The average accuracy of the models was anthesis stage > booting stage > filling stage > jointing stage. For the single-modal data framework, the model constructed with the vegetation indices was better than the aboveground biomass model constructed using the temperature or structure parameters, and the highest accuracy was obtained with an RFR model based on vegetation indices at the anthesis stage (R2 = 0.713). For the double modal data fusion approach, the highest accuracy resulted at the anthesis stage, using the structural parameters combined with the vegetation indices of the RFR model (R2 = 0.842). Even higher accuracies were obtained using the multimodal data fusion approach with an RFR model based on vegetation indices, temperature parameters and structure parameters at the anthesis stage (R2 = 0.897). By introducing terrain factors and combining them with the RFR algorithm to effectively integrate multimodal data, the complementary and synergistic effects between different remote sensing information sources could be fully exerted. The accuracy and stability of the aboveground biomass estimation models were effectively improved, and a high-throughput phenotype acquisition method was explored, which provides a reference and basis for real-time monitoring of crop growth and decoding the correlation between genotype and phenotype. [ABSTRACT FROM AUTHOR]

The law of fire occurring in the reaction of self-reactive substances is unique, when heated, comparing with common solid combustibles. In this paper, the possible thermal runaway reaction of Isoniazid storage was studied. Combined with the analysis of Isoniazid thermal stability characteristics, Fire Dynamics Simulator (FDS) was used to simulate the Isoniazid storage fire. The temperature distribution of Isoniazid storage was obtained. According to the simulation results, the temperature field of Isoniazid storage was analyzed by regression. The law of temperature distribution with height, time and distance from the center of ceiling was obtained. It was found that the ceiling temperature was highest at different heights. On the ceiling, the temperature was highest in the center. From the center to the sides, the temperature tended to drop. Therefore, when setting up the self-spraying fire extinguishing system, the sprinkler head protection roof needs to be set up, and for the stack center position, the sprinkler head should be protected. [ABSTRACT FROM AUTHOR]

• A new kind of partially coherent crescent-like beams with off-axis vortex is proposed. • The partially coherent crescent-like beams with off-axis vortex is experimentally generated. • The intensity pattern of such off-axis vortex beam possesses additional dark cores. • The off-axis vortex provides an additional degree of freedom for focus shaping. Based on the integral superposition method of constructing partially coherent beam model, a partially coherent crescent-like multi-vortex-correlated Schell-mode beam is first proposed. Numerical simulation results show that the beam possesses a crescent-like intensity distribution with multiple off-axis vortices on the source plane. By means of digital holography, the spatial light modulator was loaded with holograms, which realized experimentally the generation of this beam. The experimental normalized intensity distribution is basically consistent with the theoretical results. Adjusting the parameter N 0 , off-axis distance s and phase angle φ 0 , one can precisely control the number and position of multiple off-axis vortices. The results obtained are of importance for adjusting the beam centroid and studying vortex optics. [ABSTRACT FROM AUTHOR]

• Radiation force of a special correlated beam with multiple vortices is first derived. • Four focused hollow spots with obvious boundaries are obtained in the focal plane. • The gradient force and capture stability range increase with the increase of topological charge. • Multiple vortex beams have more capture points than the beams without vortices. In order to explore the potential application of a superimposed Hermite-Gaussian correlated Schell-model beams with off-axis multi-vortices in optical trapping, based on the generalized Collins formula, the focused beam intensity and radiation force on particles are derived in detail. Numerical results show that the gradient force and capture stability range increase with the increase of topological charge. By changing the vortex off-axis distance, the precise position control of the particles can be made. Adjusting the number of vortices can control the existence of vortex singularity on the side lobe of the beam, and generate or close the optical potential well or optical cage in real time. By selecting the appropriate beam order, two kinds of particles with different refractive indexes can be captured. The beams are expected to be applied to optical trapping of multiple particles at different positions. [ABSTRACT FROM AUTHOR]

Volcanic eruptions can release a large amount of volatiles, including sulfur dioxide and carbon dioxide, into the atmosphere and trigger regional and/or global perturbations of the climate and environment. However, the potential effect of the Linzizong volcanism, the most intense and widespread magmatism in southern Tibet, is not yet known. Here, the systematic results of fieldwork, spatial distribution analysis (area and volume), and zircon U Pb age dating of 54 samples are reported from the Linzizong volcanic rocks (Dianzhong, Nianbo and Pana Formations) in the Linzhou and Pangduo basins, southern Tibet. Our new zircon U Pb ages of 40 samples and compilations of previous data indicated that the Pana Formation erupted rapidly ca. 52–50 Ma, consistent with the coeval "flare-up" (∼51 Ma) of the Gangdese batholith. The average eruption fluxes of the lower (Dianzhong Formation), middle (Nianbo Formation), and upper (Pana Formation) parts of the Linzizong volcanic sequence are 11.8, 1.44, and 3994 km3/Ma, respectively. Evidence including the high average eruption flux (3994 km3/Ma), large magnitude (M = 8.80), and Volcanic Explosivity Index (VEI = 8) of the Pana Formation in the Linzhou and Pangduo basins suggests that this may represent a "supereruption" event in the Early Eocene. The rapid eruption of the Pana Formation was pervasive across the Tibetan Plateau and potentially extends to Sumatra, Southeast Asia, with consequences for the release of a large amount of CO 2 that could drive the Early Eocene Climatic Optimum (EECO). • Pana Formation in the Linzhou and Pangduo basins records a potential supereruption event (manitude value, M = 8.80). • Carbon flux of the Early Eocene rapid eruption of the Pana Formation was well constrained by two different methods. • Rapid eruption of the Pana Formation (∼ 52–50 Ma) in southern Tibet may be the dominant mechanism driving the EECO. [ABSTRACT FROM AUTHOR]

Hyperspectral remote sensing can quickly, nondestructively and accurately monitor crop water concentration and provide technical support for winter wheat growth monitoring, drought assessment, and variable irrigation. In this study, canopy spectral reflectance, leaf water concentration (LWC), leaf nitrogen concentration (LNC), leaf area index (LAI), and leaf dry matter (LDM) of four wheat cultivars were measured under different irrigation and nitrogen treatments, and the effects of nitrogen treatment and growth period on spectral reflectance and LWC were analyzed. Canopy spectral reflectance for different growth periods, irrigation, and nitrogen treatments showed significant changes, leading to the phenomena of "nitrogen treatment differentiation" and "growth period differentiation" for the normalized difference spectral index [NDSI (762, 1458, 2301)] and normalized difference infrared index (NDII) monitoring models. To reduce the influence of nitrogen treatment and growth period on the LWC estimation model, a modified normalized difference water index (mNDWI) was constructed by introducing the nitrogen factor (ratio of left and right peak area, RIDA) into the optimized combination of water-sensitive bands [ND (815, 1080), ND (1585, 1740), and ND (2030, 2260)]. Compared with NDSI (762, 1458, 2301), the R2 of mNDWI was improved by 36.2%–41.1% under different nitrogen levels and 18.6%–22.4% in different growth periods; this effectively reduced the impact of nitrogen status on LWC monitoring and realized the unified modeling and accurate inversion of LWC for the entire growth period. The new index mNDWI, especially mNDWI (815, 1080) and mNDWI (2030, 2260), can effectively monitor the LWC status of wheat under different cultivation conditions, which is important for the real-time diagnosis of plant moisture to guide precision field irrigation applications. [ABSTRACT FROM AUTHOR]

The Gangdese arc underwent the most intense magmatic flare-up of southern Tibet in the early Eocene (peaked at ∼50 Ma), generating widespread plutonic and volcanic rocks both along and across the arc. However, the dynamic mechanism for the magmatic flare-up is mysterious. This paper systematically analyzed the petrology, mineralogy, geochronology, and geochemistry of the early Eocene volcanic and intrusive rocks in the Pangduo basin in the eastern Gangdese arc. These rocks yielded identical zircon U Pb ages of ∼50 Ma and similar isotopic compositions. The low-silica (< 60 wt%) rocks, including basalt andesite and trachyandesite, result from low degree (2–3%) partial melting of garnet-bearing lithospheric mantle. Based on textural observations and geochemical studies, coupled with Rhyolite-MELTS modeling and zircon trace elements Rayleigh fractionation models, the following research results were obtained. The high-silica rhyolite, ignimbrite, and granite porphyry are the product of limited melt extraction, while the quartz monzonite belongs to the associated residual silicic cumulates. The quartz monzonitic porphyry and trachydacite show a widespread dissolution structure and high formation temperature of ∼850 °C. Whole-rock geochemical mixing model results indicate that they are generated by mixing products of mafic magma, high-silica melts, and remelting melts of quartz monzonite. The volcanic and intrusive rocks in the Pangduo basin are considered as a volcanic-plutonic complex, resulting from the synergistic effect of melt extraction and cognate magma mixing. Both the complex magmatic processes and the early Eocene magmatic flare-up are attributed to mafic magma injection. • The Pangduo volcanic-plutonic complex with various rock types is well exposed in the Pangduo basin, southern Tibet. • The rhyolitic ignimbrite and the quartz monzonite are extracted melts and corresponding residual cumulates, respectively. • Melt extraction and magma mixing via mafic magma injection promote the large-scale magma formation. [ABSTRACT FROM AUTHOR]

The radiance of sky brightness differs principally with wavelength passband. Atmospheric scattering of sunlight causes the radiation in the near-infrared band. The Antarctic is a singular area of the planet, marked by an unparalleled climate and geographical conditions, including the coldest temperatures and driest climate on Earth, which leads it to be the best candidate site for observing in infrared bands. At present, there are still no measurements of night-sky brightness at DOME A. We have developed the Near-Infrared Sky Brightness Monitor (NISBM) in the J ,  H , and K s bands for measurements at DOME A. The instruments were installed at DOME A in 2019 and early results of NIR sky brightness from 2019 January–April have been obtained. The variation of sky background brightness with solar elevation and scanning angle is analysed. The zenith sky flux intensity for the early night at DOME A in the J band is in the 600–1100 μJy arcsec−2 range, that in the H band is between 1100 and 2600 μJy arcsec−2, and that in the K s band is in the range ∼200–900 μJy arcsec−2. This result shows that the sky brightness in J and H bands is close to that of Ali in China and Mauna Kea in the USA. The sky brightness in the K s band is much better than that in Ali, China and Mauna Kea, USA. This shows that, from our early results, DOME A is a good site for astronomical observation in the K s band. [ABSTRACT FROM AUTHOR]

Background: Limited research has looked at the physical activity (PA) among Chinese children and adolescents with intellectual disabilities. Methods: The Children's Leisure Activities Study Survey‐Chinese version was applied in evaluating PA levels among children and adolescents with intellectual disabilities. Results: The data indicated that only 29.5% of children and adolescents with intellectual disabilities met the PA recommendation. Boys engaged in significantly more MVPA and had higher energy expenditure than girls during weekdays and the whole week. The general trend in PA levels demonstrated a downtrend with the growth of age of children and adolescents with intellectual disabilities. The students aged 6–12 years old performed more MVPA and had greater energy expenditure compared with those 13–15 and 16–18 years old. Conclusion: The level of PA among Chinese children and youths with intellectual disabilities is remarkably low, and there is a large gap compared with the PA recommendation. [ABSTRACT FROM AUTHOR]

The orogenic process and crustal growth of the Changning–Menglian Palaeo-Tethys orogenic belt in the southeastern Tibetan Plateau is not fully understood. Triassic Caojian rhyolites and granites occur extensively in this orogenic belt and represent important constraints for this issue. This study aims to examine the relationships between the Triassic Caojian rhyolites and granites and to gain a better understanding of their possible petrogenesis. The study used zircon U–Pb geochronology, trace element analyses and Sr–Nd–Hf isotope data to better understand the relationships and possible origin of the rhyolites and granites. Recent zircon U–Pb ages indicated that the Caojian rhyolites were emplaced at 227.2 Ma, whereas age estimates for Caojian granites were slightly older (233.4–236.9 Ma). The Caojian rhyolites are enriched in large-ion lithophile elements and high-field-strength elements, with elevated FeOtot/MgO and Ga/Al ratios. However, they are significantly depleted in Ba, Sr, Eu, P and Ti. These geochemical characteristics indicate that they have an A-type affinity. Furthermore, the Caojian granites comprise biotite monzogranites and granodiorites and show unfractionated composition. Mineralogically, the Caojian granites were found to contain diagnostic I-type minerals such as hornblende. Geochemical data suggest that the petrogenesis of the Triassic Caojian rhyolites is characterized by rejuvenation of crystal mush represented by the Triassic Caojian granites. The necessary thermal input was supplied by mafic magma. This magmatic evolution was likely related to lithospheric delamination and upwelling of the asthenosphere during the Mid- to Late Triassic, forming post-collisional I-type granites and A-type volcanics in the Changning–Menglian Palaeo-Tethys orogenic belt. [ABSTRACT FROM AUTHOR]

[Display omitted] • The Mengku dacites, Lincang granites and diorites are spatially and temporally related. • The Triassic Mengku dacites is characterized by rejuvenation of the Lincang crystal mush. • The thermal input was supplied by mafic magma represented by the Lincang diorites. • Magmatic evolution was related to mantle upwelling in the post-collisional setting. The tectono-magmatic event of the Changning-Menglian Paleo-Tethys orogen is an important process for understanding the tectonic evolution of the SE Tibetan Plateau. This orogen is composed of Changning-Menglian suture, Lancang group, Lincang batholith, and Yunxian volcanics. The Lincang batholith and its volcanic counterparts are part of Triassic magmatism in this orogen. The botholith is composed of biotite monzogranite, granodiorite and diorite. The Middle to Late Triassic volcanics include Manghuai rhyolite, Xiaodingxi basalt and Mengku dacite. The Mengku dacite is volcanic dome in west of the batholith. Lincang biotite monzogranite and Mengku dacite have similar geochemistry and are characterized by negative ε Hf (t) values (–13.2 to –5.2) and ε Nd (t) values (–14.7 to –8.8), whereas diorite dikes within the Lincang batholith have slightly high ε Hf (t) values (–8.3 to –4.9) and ε Nd (t) values (–6.9 to –6.7). Manifestations of resorption textures in quartz and reverse compositional zoning in feldspars are recognized from Mengku dacite. We consider that Mengku dacites resemble the erupted Lincang biotite monzogranite as they occur in the same tectonic settings and have similar geochemical features and mineral assemblages dominated by plagioclase, alkali-feldspar, quartz, and biotite. The evolution of the Mengku dacite magma is characterized by the rejuvenation of crystal mush represented by the Lincang batholith. The required thermal input was supplied by mafic magma, represented by diorite dikes and enclaves within the Lincang batholith. The Middle to Late Triassic magmatic event in this orogen likely resulted from lithospheric delamination and upwelling of the asthenosphere in a post-collisional environment. [ABSTRACT FROM AUTHOR]

A dynamic model for a hydro-turbine governing system is established that accounts for the periodic excitation caused by the dynamic transfer coefficient. The dynamic analysis shows that the turbine regulation system produces bursting oscillatory behaviors when its transmission coefficient changes. The bursting oscillation behavior can adversely affect its stable operation. In response to this challenge, a prescribed performance sliding mode controller based on the time-varying tangent barrier Lyapunov function is proposed. Specifically, a time-varying constraint function of the exponential decay type is initially established. This function is then combined with the prescribed performance constraint function and the dynamic sliding surface to construct the time-varying tangent barrier Lyapunov function. In addition, to ensure that the system output exhibits a slight overshoot and fast-tracking speed at the initial time while satisfying the steady-state index, the relevant parameters of the time-varying constraint function are presented. Finally, the stability of the proposed controller is rigorously proven, verifying the effectiveness of the controller under five working conditions. The simulation results demonstrate that the prescribed performance sliding mode control based on the time-varying tangent barrier Lyapunov function can enable the hydro-turbine governing system to quickly break away from the bursting oscillation state. The proposed control strategy achieves faster convergence times for the rotor angle and generator speed (0.3 s) as well as the guide vane opening (0.3 s) than the ordinary sliding mode controller. The proposed strategy is also superior in controlling the steady-state error, which means that the proposed controller has a faster response speed, higher control accuracy, and optimized transient performance of the system than the traditional controller. • The hydro-turbine regulation system under periodic excitation exhibits bursting oscillations. • Prescribed performance control to handle state constraint problems. • Indirect constraints on the state are achieved by constraining the sliding surface. • The controller still has better performance when the parameters change. [ABSTRACT FROM AUTHOR]

The similarity criterion for high speed or high enthalpy rarefied reaction flows is the binary scaling law, one of which is the product of the incoming flow density and the characteristic scale of the test model in a rarefied wind tunnel should be equal to that under the flight condition. This is to ensure that the ratio between the characteristic distance of the relaxation process and the characteristic length of the body is equal. However, in a rarefied wind tunnel, it is difficult to directly measure the flow density below 10−5 kg/m3 using common methods due to the relatively high rarefied degree, an indirect density estimation method based on force analysis of a pendulum sphere was proposed in this study. The oscillation trajectory of the pendulum sphere under ultrahigh-speed rarefied flow conditions was recorded and the corresponding aerodynamic drag force acted on the sphere along the trajectory was analyzed, based on which the density distribution of the flow was then estimated combined with DSMC simulations. The obtained results show that in the present study, the flow is in under-expanded condition and the measured density sharply decreased from 10−6 kg/m3 to 10−7 kg/m3 at 140–170 mm from the nozzle outlet. • An indirect density measurement method for ultrahigh-speed rarefied flow filed was presented. • The aerodynamic forces acting on a small pendulum sphere in a rarefied flow can be obtained quite precisely and easily by analyzing its oscillation trajectory experimentally. • By comparing the obtained forces with those simulated by DSMC, the flow density as low as 10-6- 10-7 kg/m3 could be estimated which is usually hard to be measured using conventional method. [ABSTRACT FROM AUTHOR]