Modular floating solar farms exhibit periodic open surface coverages due to the strip configuration of floating modules that support the photovoltaic (PV) panels on top. The associated modulations in the surface boundary layer and its turbulence characteristics are investigated in the present study under fully developed open channel flows. Different coverage percentages of 100 % (i.e. full cover), 60 %, 30 % and 0 % (i.e. open surface) were tested and measurements were obtained using particle image velocimetry. The results showed that the turbulence statistics are similar when the coverage decreases from 100 % to 60 %. However, with 30 %, both the turbulence intensities and Reynolds stresses increase substantially, reaching up to 50 % higher compared with the 100 % coverage, and the boundary layer thickness increases by more than 25 %. The local skin friction beneath the openings increases by 50 %. Analysis of spanwise vortices and premultiplied spectra indicates that the periodic coverage elongates the hairpin vortex packets and reduces their inclination angle, imposing limitations on sustainable coherent structures. At 30 %, flow detachment and smaller-scale vortices become dominant, reducing the mean velocities and increasing the turbulence intensities. Decreasing coverage percentage with flow detachment also shifts the energy transfer to higher wavenumbers, increasing energy dissipation and decreasing the bulk flow velocity. The kinetic energy and Reynolds stress carried by very large-scale motions decreases from 40 %–50 % with the 100 % and 60 % coverage to around 30 %–40 % with the 30 % coverage. Further research studies involving spanwise heterogeneity, higher Reynolds number and varying submergence of PV modules are needed for environmental considerations.

The Weng'an Biota from the Ediacaran Doushantuo Formation in Guizhou Province, southwestern China, is known for its three-dimensionally phosphatized acritarchs, multicellular algae, and embryo-like animal fossils. Among these diverse microfossils, acanthomorphic acritarchs have played a significant role in the biostratigraphic subdivision and correlation of the lower-middle Ediacaran System. However, most previous studies on the biostratigraphy of the Doushantuo Formation in the Weng'an area have focused on large acanthomorphic acritarchs (LAAs, vesicle diameter >200 μm), whereas the smaller acanthomorphic acritarchs (SAAs, vesicle diameter <100 μm) from the Weng'an Biota have been largely overlooked. In this study, we examined >500 thin sections and discovered a large number of well-preserved, small (<100 μm) and medium-sized acanthomorphic acritarchs (MAAs, vesicle diameter ranging 100–200 μm). In total, we have identified SAAs in four genera and six species (Tanarium conoideum Kolosova, 1991, emend. Moczydłowska et al., 1993; Tanarium elegans Liu et al., 2014; Mengeosphaera membranifera Shang, Liu, and Moczydłowska, 2019; Mengeosphaera minima Liu et al., 2014; Estrella recta Liu and Moczydłowska, 2019; Variomargosphaeridium gracile Xiao et al., 2014), as well as two types of MAAs (Tanarium tuberosum Moczydłowska, Vidal, and Rudavskaya, 1993, emend. Moczydłowska, 2015; Weissiella cf. W. grandistella Vorob'eva, Sergeev, and Knoll, 2009, emend. Liu and Moczydłowska, 2019). This updated acritarch assemblage of the Weng'an Biota is valuable for correlating the Ediacaran Doushantuo Formation between the Weng'an and Yangtze Gorges areas. It also serves as a tool to test the proposed acritarch biozones in Ediacaran formations of South China and other localities, including Australia, Siberia, and the East European Platform.

There are many types of approaches for Paraphrase Identification (PI), an NLP task of determining whether a sentence pair has equivalent semantics. Traditional approaches mainly consist of unsupervised learning and feature engineering, which are computationally inexpensive. However, their task performance is moderate nowadays. To seek a method that can preserve the low computational costs of traditional approaches but yield better task performance, we take an investigation into neural network-based transfer learning approaches. We discover that by improving the usage of parameters efficiently for feature-based transfer, our research goal can be accomplished. Regarding the improvement, we propose a pre-trained task-specific architecture. The fixed parameters of the pre-trained architecture can be shared by multiple classifiers with small additional parameters. As a result, the computational cost left involving parameter update is only generated from classifier-tuning: the features output from the architecture combined with lexical overlap features are fed into a single classifier for tuning. Furthermore, the pre-trained task-specific architecture can be applied to natural language inference and semantic textual similarity tasks as well. Such technical novelty leads to slight consumption of computational and memory resources for each task and is also conducive to power-efficient continual learning. The experimental results show that our proposed method is competitive with adapter-BERT (a parameter-efficient fine-tuning approach) over some tasks while consuming only 16% trainable parameters and saving 69-96% time for parameter update.

Metamorphic robots are a new type of unmanned vehicle that can reconfigure and morph between a car mode and a biped walking machine mode. Such a vehicle is superior in trafficability because it can drive at high speeds on its wheels on structured pavement and walk on its legs on unstructured pavement. An engineering prototype of a metamorphic robot was proposed and designed based on the characteristics of wheeled–legged hybrid motion, and reconfiguration planning of the robot was conducted. A kinematics model of the reconfiguration process was established using the screw theory for metamorphic robots. To avoid component impact during the rapid global reconfiguration and achieve smoothness of the reconfiguration process, a rotation rule for each rotating joint was designed and the kinematics model was used to simulate and validate the motion of the system’s end mechanism (front frame) and the entire robot system. Based on the kinematics model and the rotation rules of the rotating joints, a zero-moment point (ZMP) calculation model of the entire robot mechanism in the reconfiguration process was established, and the stability of the reconfiguration motions was evaluated based on the ZMP motion trajectory. The foot landing position was optimized to improve the robot’s stability during the reconfiguration. Finally, the smoothness and stability of the reconfiguration motion were further validated by testing the prototype of the metamorphic robot.

Baseline data on local status of threatened species are often limited, and alternative information sources such as local ecological knowledge (LEK) have potential to provide conservation insights but require critical evaluation. We assess the usefulness of LEK to generate conservation evidence for the Hainan Peacock-pheasant Polyplectron katsumatae, a poorly known threatened island galliform. Interview surveys in rural communities across eight forested landscapes on Hainan provided a new dataset of sightings of Peacock-pheasants and other galliforms. Fewer respondents had seen Peacock-pheasants compared to other species across most landscapes, although Peacock-pheasant sightings showed significant across-landscape variation, with substantially more total and recent sightings from Yinggeling National Nature Reserve. However, validation of interview data with camera trapping data from Houmiling Provincial Nature Reserve, a landscape with few reported sightings, suggests a more optimistic possible status for Peacock-pheasants, which were detected as frequently as Red Junglefowl Gallus gallus and Silver Pheasant Lophura nycthemera during systematic camera trap placement. Hainan Peacock-pheasant sighting rates might be influenced by various factors (e.g. restricted local access to forests), with absolute abundance possibly greater than expected from limited sightings. Conversely, relative across-landscape abundance patterns from LEK are likely to be valid, as similar detection biases exist across surveyed landscapes.

Thyroid cancer (TC) incidence has increased greatly during the past decades with a few established risk factors, while no study is available that has assessed the association of the Chinese Health Dietary Index (CHDI) with TC. We conducted a 1:1 matched case–control study in two hospitals in Shanghai, China. Diet-quality scores were calculated according to CHDI using a validated and reliable FFQ. Conditional logistic regression analysis and restricted cubic spline analysis were used to reveal potential associations between CHDI score and TC risk. A total of 414 pairs of historically confirmed TC patients and healthy controls were recruited from November 2012 to December 2015. The total score of cases and controls were 67·5 and 72·8, respectively (P < 0·001). The median score of total vegetables, fruit, diary products, dark green and orange vegetables, fish, shellfish and mollusk, soyabean, whole grains, dry bean and tuber in cases was significantly lower than those in controls. Compared with the reference group (≤60 points), the average (60–80 points) and high (≥80 points) levels of the CHDI score were associated with a reduced risk of TC (OR: 0·40, 95 % CI 0·26, 0·63 for 60–80 points; OR: 0·22, 95 % CI 0·12, 0·38 for ≥80 points). In age-stratified analyses, the favourable association remained significant among participants who are younger than 50 years old. Our data suggested that high diet quality as determined by CHDI was associated with lower risk of TC.

The North China Plain suffers excessive application of nitrogen (N) and soil degradation. Recently, biochar has been promoted as an agricultural soil amendment to ameliorate soil quality, increase crop yield and mitigate greenhouse gas emissions. However, most proofs on the positive effects of biochar addition have been based on small plots or short-term field studies located in tropical or subtropical regions with defective soils. A long-term field experiment was designed with five N levels and two biochar rates to observe the changes in crop (winter wheat and summer maize) growth and soil chemical quality. Notably, crop yield was strongly dependent upon N application, with both wheat and maize yields increasing with N application. Biochar addition increased crop yield but not significantly, although the increase in grain yield was 0.96 t/ha in a rotation. Correlation analysis revealed that the optimal root-layer soil mineral N (Nmin) for crop production was around N120, especially with biochar addition. The effect of fertilization on soil chemical quality was mainly reflected in the increase in soil organic carbon (SOC), and the highest value was obtained at N60 whether or not biochar was applied. Overall, biochar addition did not appear to promote wheat and maize growth or increase the yield on calcareous alluvial soils in temperate regions, but significantly enhanced SOC content, especially at N60, which may play an important role in sustainable agricultural production.

The dependence of fishbone cycle on energetic particle intensity has been investigated in EAST low-magnetic-shear plasmas. It is observed that the fishbone mode growth rate, saturation amplitude as well as fishbone cycle frequency clearly increase with increasing neutral beam injection (NBI) power. Moreover, enhanced electron density and temperature perturbations as well as energetic particle loss were observed with greater injected NBI power. Simulation results using M3D-K code show that as the NBI power increases, the resonant frequency and the energy of the resonant particles become higher, and the saturation amplitude of the mode also changes, due to the non-perturbative energetic particle contribution. The relationship between the calculated energetic particle pressure ratio and fishbone cycle frequency is obtained as ${f_{\textrm{FC}}} = 2.2{(1000{\beta _{\textrm{ep,calc}}} - 0.1)^{5.9 \pm 0.5}}$. Results consistent with the experimental observations have been achieved based on a predator–prey model.

This study introduces a new real-time kinematic (RTK) positioning method which is suitable for baselines of different lengths. The method merges carrier-phase wide-lane, and ionosphere-free observation combinations (LWLC) instead of using pseudo-range, and carrier-phase ionosphere-free combination (PCLC), or single-frequency pseudo-range and phase combination (P1L1). In a first step, the double-differenced wide-lane ambiguities were calculated and fixed using the pseudo-range and carrier-phase wide-lane combination observations. Once the double-differenced wide-lane integer ambiguities were known, the wide-lane combined observations were regarded as accurate pseudo-range observations. Subsequently, the carrier-phase wide-lane, and ionosphere-free combined observations were used to fix the double-differenced carrier-phase integer ambiguities, achieving the final RTK positioning. The RTK positioning analysis was performed for short, medium, and long baselines, using the P1L1, PCLC, and LWLC methods, respectively. For a short baseline, the LWLC method demonstrated positioning accuracy similar to the P1L1 method, and performed better than the PCLC method. For medium and long baselines, the positioning accuracy of the LWLC method was slightly higher than those of the PCLC and P1L1 methods. In conclusion, the LWLC method provided high-precision RTK positioning results for baselines with different lengths, as it used high-precision carrier-phase observations with fixed ambiguities instead of low-precision pseudo-range observations.

We report on a high-power Ho:YAG single-crystal fiber (SCF) laser inband pumped by a high-brightness Tm-fiber laser at 1908 nm. The Ho:YAG SCF grown by the micro-pulling-down technique exhibits a propagation loss of $0.05\pm 0.005~\text{cm}^{-1}$ at $2.09~\unicode[STIX]{x03BC}\text{m}$. A continuous-wave output power of 35.2 W is achieved with a slope efficiency of 42.7%, which is to the best of our knowledge the highest power ever reported from an SCF-based laser in the 2 $\unicode[STIX]{x03BC}\text{m}$ spectral range.

The Tamusu region in northwest China is a key candidate area for China's clay rock deep geological repositories (DGRs) for high-level radioactive waste (HLRW) as it is composed of a continuous layer of thick lacustrine mudstone. To evaluate this mudstone as a host rock, two special test boreholes were drilled to investigate its spatial distribution and mineralogical and hydraulic characteristics. The southwest boundary and depositional centre of the lake basin were well delineated by boreholes TZK-1 and TZK-2. The continuous single-layer thickness of the target mudstone formation was up to 300 m at a depth of 500–800 m. Three main mineral types were determined, namely carbonates (mainly dolomite and ankerite), analcime and albite, and their abundance was used to distinguish three different facies. Other mineral phases, such as clay minerals (mainly illite and kaolinite), pyrite, hematite, quartz and calcite, were present as admixtures. The presence of carbonates may increase the mechanical strength and analcime may enhance the radionuclide adsorption properties of the mudstone. The self-sealing properties, which may be affected by the small amount of clay minerals, remain to be investigated. The hydraulic conductivity of the mudstone determined via in situ pulse tests ranged from 10–13 to 10–10 m s–1, suggesting that the Tamusu mudstone has ultra-low permeability. The transmissivity of the Tamusu mudstone fluctuated in regions with varying lithologies, but remained relatively constant for consistent lithologies. In summary, these preliminarily results confirm the possible suitability of the target formation as a host rock for DGRs of China's HLRW.

Based on dust storm frequency (DSF) data from the China Meteorological Administration, Arctic sea-ice concentration (SIC) data from the Hadley Centre, and atmospheric reanalysis data from the National Centers for Environmental Prediction (NCEP) and National Center for Atmospheric Research (NCAR), temporal variations and regime shifts of East Asian DSF and Arctic SIC during 1961–2015 are revealed, and the possible relationship between them is explored. The results show that East Asian DSF in spring is closely associated with the preceding winter SIC from the northern Greenland Sea to the Barents Sea (20° W–60° E, 74.5° N–78.5° N). In the past half-century, both East Asian DSF and Arctic SIC have shown significant declining trends, with consistent regime shifts in the early 1980s. Further statistical analyses indicate that the abrupt decrease of East Asian DSF in spring may be attributed to the concurrent sharp loss of Arctic SIC in the preceding winter. It is the loss of Arctic SIC that causes the atmospheric circulation anomalies downstream by stimulating a Rossby wave train, resulting in decelerated wind speed, dampened vertical wind shear and restrained synoptic-scale disturbances over the dust source region, eventually leading to the decline in East Asian DSF over decadal timescales.

Signal-in-space (SIS) continuity and availability are important indicators of performance assessment for Global Navigation Satellite Systems (GNSSs). The BeiDou Navigation Satellite System (BDS) Open Service Performance Standard (BDS-OS-PS-1.0) has been released, and the corresponding public performance indicators have been provided, but the actual SIS performance is uncertain to users. SIS continuity and availability are primarily related to unscheduled outages (failures). Therefore, based on the existing failure classification system and actual operation modes, four types of failure modes are first analysed: long-term failure related to satellite service period, maintenance failure related to satellite manoeuvring, short-term failure associated with random repairable anomalies and equivalent failure corresponding to a combination of the above three types of failures. Second, based on the failure classification and selected precise and broadcast ephemerides from 2015–2016, the Mean Time Between Failure (MTBF) and Mean Time To Repair (MTTR) of each failure type are obtained using appropriate detection methods. Finally, using a corresponding assessment model, the SIS continuity and availability of BeiDou are calculated for individual and equivalent failure cases, and these are compared with the provided index in the BDS Open Service Performance Standard.

Social media play an important role in emergency management. The location of citizens and distance from a disaster influence the social media usage patterns. Using the Tianjin Port Explosion, we apply the correlation analysis and regression analysis to explore the relationship between online engagement and location. Citizens’ online engagement is estimated by social media. Three dimensions of the psychological distance – spatial, temporal, and social distances – are applied to measure the effects of location and distance. Online engagement is negatively correlated to such 3 kinds of the distance, which indicates that citizens may pay less attention to a disaster that happens at a far away location and at an area of less interaction or at a relatively long period of time. Furthermore, a linear model is proposed to measure the psychological distance. The quantification relationship between online engagement and psychological distance is discussed. The result enhances our understanding of social media usage patterns related to location and distance. The study gives a new insight on situation awareness, decision-making during disasters.

The dust cycle plays an important role in the long-term evolution of the climate and environment. In this paper, an improved climate model including aerosol processes was used to carry out a set of sensitivity experiments and comparative analyses of the effects of high-latitude ice-sheet extent and abnormal dust erosion, as well as Earth’s orbital parameters and atmospheric greenhouse gas content, on dust activities during the last glacial maximum. The comparative analysis found that incorporating the abnormal surface erosion factor alone could increase dust emissions by 2.77-fold and 3.77-fold of the present-day global and Asian dust emissions, respectively. The high-latitude ice-sheet factor caused global dust emissions to increase by 1.25-fold that of the present day. Sensitivity experiments showed that increased surface erosion in Asia during the last glacial maximum made the greatest contribution to the increased dust emissions in Asia, followed by the high-latitude ice-sheet factor, while the contributions of the greenhouse gas content and orbital parameters were relatively weak. Strong dust emissions during the glacial period were therefore not only dependent on the development of the high-latitude ice sheets but were strongly associated with the underlying surface characteristics of local dust source regions.

A field study to optimize the nitrogen (N) top-dressing mode of panicle fertilization and improve rice yields was conducted in mid-eastern China. Japonica cultivar Yunongjing-6 was grown and panicle N fertilizer was applied at the beginning of the inverted fourth leaf stage using three different modes: manual broadcast application (BA) on the soil surface as a control treatment, deep application during ditching at a depth of 15 cm (DD) and manual BA on the soil surface during deep ditching (BAD). The activity of soil enzymes, including invertase, urease, phosphatase and catalase, was increased significantly at the jointing, booting and grain-filling stages with the DD and BAD treatments compared with the traditional BA mode. The DD and BAD treatments also increased basal internode and neck-panicle internode bleeding intensity. The DD treatment gave the highest crop yield, increasing the yield by 0.63 and 0.31 t/hm2 in 2011 and 2012, respectively, compared with BA. The results suggest that ditching during panicle N fertilizer application after sun-drying of the fields increases rice yields, most likely by improving the activity of soil enzymes and enhancing the physiological activity of roots and grain weight.

Underground Nuclear Astrophysics in China (JUNA) will take the advantage of the ultra-low background in Jinping underground lab. High current accelerator with an ECR source and detectors were commissioned. JUNA plans to study directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies. At the first period, JUNA aims at the direct measurements of 25Mg(p,γ)26 Al, 19F(p,α) 16 O, 13C(α, n) 16O and 12C(α,γ) 16O near the Gamow window. The current progress of JUNA will be given.

Strain path changes during clock rolling cause more serious interaction between adjacent grains, resulting in the occurrence of interactive regions (IRs) with random orientations. Furthermore, plenty of new grains with relatively random orientations are introduced by the subsequent annealing of these IRs. The morphology of the IR and the origin of random orientations were therefore investigated in this study, and the electron backscatter diffraction technique was used to characterize crystallographic orientations of nuclei and deformed matrices. A short-time annealing was imposed on a specimen to catch the transient nucleation behaviors. The results indicate that the orientations of nuclei are similar to their surrounding deformed matrices, especially the points with larger local-misorientation. Additionally, the shape of new grains depends on where it forms, and it is suggested that this fact mainly results from the great difference in stored energies between deformed matrices with {111} and {100} orientations.