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Inchworm piezoelectric actuators have attracted much attention in the field of precision positioning due to the advantages of a large stroke, high output force, and high resolution. However, traditional inchworm piezoelectric actuators use two sets of clamps and a set of drive structures to achieve stepping motion, which generally requires at least three piezoelectric stacks, resulting in a complex structure and the control system. Several methodologies have been advanced to minimize the utilization of piezoelectric stacks. However, there still exists the issue of excessive volume. Therefore, an inchworm piezoelectric actuator with a single-clamp and single drive structure is proposed in the study, which provides a compact size and smaller volume. The clamping mechanism comprises two sets of clamping feet with opposite displacement, which alternate contact with the guide frame and adjustable plate to ensure that the clamping mechanism always has frictional force and accomplishes the stepping motion. The testing of the actuator's step distance, output force, and other parameters was conducted utilizing a displacement sensor. Experimental results indicate that the actuator achieved a maximum speed of 174.3 μm/s and an output force of 8.6 N when the frequency and voltage were 19 Hz and 150 V. [ABSTRACT FROM AUTHOR]

Water resources management and planning traditionally focus on visible liquid or blue water. However, green water also maintains social development and ecosystem services. Therefore, blue and green water should be incorporated into the watershed management system for evaluating water resources. To analyze the water resources of the Hanjiang River Basin, the SWAT model was set up using long-term and high-precision geographic data. The methods of wavelet analysis and Pearson's correlation analysis were used to explore the influence mechanism of climate and vegetation changes on the blue and green water flow (BWF and GWF) of the main ecosystems in the basin. The results showed that: (1) The spatial–temporal distribution of the BWF and GWF in the main ecosystems of the basin over the past 50 years was uneven. Forest ecosystems and farmland ecosystems have a greater concentration of water resources in the south, while grassland ecosystems have a greater concentration of water resources in the east. (2) Climate dominates the BWF and GWF changes in the main ecosystems of the basin. The BWF and the precipitation change cycle are synergistic, and the GWF and the temperature change cycle are synergistic. (3) The correlation between vegetation and BWF and GWF in the farmland ecosystem is significant. Vegetation affects the hydrological change process of the BWF and GWF at the microscale. This study can provide data support and scientific rules for ecosystem water resource management in the basin. [ABSTRACT FROM AUTHOR]

Simple Summary: The invasive pest Spodoptera frugiperda has become a global problem. Sterile insect technology is an effective means to prevent invasive insects, but at present, the research on this pest is not perfect. Our results showed that egg sterility in offspring reached 74% when the ratio of those given a 250 Gy dose of X-ray radiation to the non-irradiated males was 12:1, and there was no significant difference in mating competitiveness between irradiated males of different ages. Additional cornfield cage studies confirmed this finding by showing that release ratios from 12:1 to 20:1 significantly reduced larval populations in the field, with a 48 to 69% leaf protection effect and a 58 to 83% insect population reduction. This study provides fundamental information for the management of S. frugiperda through the use of sterile insect techniques. Spodoptera frugiperda, an invasive pest, has a huge impact on food production in Asia and Africa. The potential and advantages of sterile insect techniques for the permanent control of S. frugiperda have been demonstrated, but the methods for their field application are still unavailable. For the purposes of this study, male pupae of S. frugiperda were irradiated with an X-ray dose of 250 Gy to examine the effects of both the release ratio and the age of the irradiated males on the sterility of their offspring. The control effect of the irradiated male release ratio on S. frugiperda was evaluated using field-cage experiments in a cornfield. The results showed that when the ratio of irradiated males to non-irradiated males reached 12:1, the egg-hatching rate of the offspring of S. frugiperda decreased to less than 26%, and there was also no significant difference in mating competitiveness among the different ages. Field-cage testing showed that when irradiated males were released at ratios of 12:1–20:1 to normal males, the leaf protection effect for the corn reached 48–69% and the reduction in the insect population reached 58–83%. In this study, an appropriate release ratio is suggested, and the mating competitiveness of irradiated and non-irradiated males of S. frugiperda is investigated, thus providing a theoretical basis for the use of sterile insect techniques to control S. frugiperda. [ABSTRACT FROM AUTHOR]

The water conservation function of ecosystems is a research hot spot in the field of water resources, and it is also an important ecological service function of terrestrial ecosystems and a key point in eco-hydrology research. With the increasing frequency of human activities and climate change, how to reveal the response of ecosystem water conservation function to the changing environment is a scientific problem that needs to be urgently addressed in ecological hydrology research. To reveal the eco-hydrological processes under the changing environment, this study was based on the distributed hydrological model (SWAT) and used water conservation amount (WCA) as an indicator to assess the water conservation capacity of ecosystems. Scenario analysis and statistical analysis were also used to determine the spatial and temporal evolution of the WCAs of farmland, forest, and grassland ecosystems under a changing environment and to further investigate the influence mechanisms of land use change and climate change on the WCA. The findings show that (1) the climate conditions in the Hanjiang watershed have determined the distribution pattern of the ecosystem's WCA. The spatial distribution patterns of the WCA of each ecosystem differed significantly between the dry season and the wet season. Under the combined influence of human activities and climate change, there was no significant change in the spatial distribution pattern of the WCA. (2) Climate change patterns, which were dominated by precipitation and influenced by evapotranspiration, determined the changes in the WCA of ecosystems. In addition, there were significant spatial differences in the response of the watershed WCA under changing environments in the dry season. Differences in land use type and local climate change were the main reasons for such differences. (3) There were differences in the WCA and the response to changing environments among ecosystems. Forest ecosystems had the highest WCA; grassland ecosystems were the most sensitive to land use change. This study can provide a theoretical basis for alleviating the increasingly serious water resource problems in the basin and ensuring water and ecological security in the basin. [ABSTRACT FROM AUTHOR]

Cicadae Periostracum (CP) is a traditional Chinese medicinal herb derived from the slough that is molted from the nymph of the insect Cryptotympana pustulata Fabricius. Washing with water to remove residual silt is a primary processing method of CP that is recommended by the Chinese Pharmacopoeia, but how washing methods affect the quality and bioactivity of CP is unknown. In this study, the quality and bioactivity of non-washed CP (CP-NW), post-molting-washed CP (CP-WAT), and pre-molting-washed CP (CP-WBT) were comparatively investigated. The quality of these CP samples was evaluated in terms of the UPLC-QTOF-MS/MS-based chemical profiling and semi-quantification of 39 N-acetyldopamine oligomers (belonging to six chemical types), the HPLC-UV-based quantification of 17 amino acids, the ICP-MS-based quantification of four heavy metals, and the contents of ash; the bioactivities of the samples were compared regarding their anti-oxidant and anti-inflammatory activities. It was found that, compared with CP-NW, both CP-WBT and CP-WAT had significantly lower contents of ash and heavy metals. Moreover, compared with CP-WAT, CP-WBT contained lower levels of total ash, acid-insoluble ash, and heavy metals and higher contents of N-acetyldopamine oligomers and amino acids. It also had enhanced anti-oxidant and anti-inflammatory activities. A Spearman's correlation analysis found that the contents of N-acetyldopamine oligomers and free amino acids were positively correlated with the anti-oxidant/-inflammatory activities of CP. All these results suggest that pre-molting washing can not only remove the residual silt but can also avoid the loss of the bioactive components and assure higher bioactivities. It is concluded that pre-molting washing could enhance the quality and bioactivity of CP and should be a superior alternative method for the primary processing of qualified CP. [ABSTRACT FROM AUTHOR]

This paper proposes a dual-harmonic pole-changing (PC) motor with split permanent magnet (PM) poles (DHPCM-SPMPs). By adopting a split PM pole structure, the amplitude of the third PM flux density is increased greatly. Therefore, when a PC winding is adopted to couple with the fundamental and third PM flux density components, respectively, the proposed motor can work as a PC PM motor to satisfy operating demands of electric tractors. The design and effect of the proposed split PM pole structure is introduced first. The winding topology is then designed according to the slot vector diagrams of the two PM flux density components, and the PC operation can be realized by electric switches. Aiming at a torque ratio design objective, the PM structure parameters can be determined based on mathematical derivation, and the speed-widening capability is proved based on the operation characteristic analysis. Finally, the electromagnetic performance of the DHPCM-SPMPs is investigated and compared by finite element analysis, which shows the high torque capability in eight-pole mode and the wide speed range in twenty-four-pole mode benefiting from the PC operation. [ABSTRACT FROM AUTHOR]

A combined tip-sample scanning architecture can improve the imaging speed of atomic force microscopy (AFM). However, the nonorthogonality between the three scanners and the nonideal response of each scanner cause measurement errors. In this article, the authors systematically analyze the influence of the installation and response errors of the combined scanning architecture. The experimental results show that when the probe in the homemade high-speed AFM moves with the Z-scanner, the spot position on the four-quadrant detector changes, thus introducing measurement error. Comparing the experimental results with the numerical and theoretical results shows that the undesired motion of the Z-scanner introduces a large error. The authors believe that this significant error occurs because the piezoelectric actuator not only stretches along the polarization direction but also swings under nonuniform multifield coupling. This article proposes a direction for further optimizing the instrument and provides design ideas for similar high-speed atomic force microscopes. [ABSTRACT FROM AUTHOR]

Fixed exposure will lead to underexposure or overexposure of collected flame radiation images using CCD, which has a great influence on the temperature measuring accuracy. A temperature measurement method was proposed by image fusion with multi-exposure, which can eliminate the influence of insufficient underexposure and overexposure. The approach was first to acquire a group of flame radiation images during different exposures. Then a partial region with good exposure effect in each radiation image was obtained by segmentation, with which the complete flame image can be spliced together. An experimental system was built to calibrate the temperature measurement parameters by two-color pyrometry through a blackbody furnace. The relation between exposure time and monochromatic gray level, as well as the relation between the temperature and temperature measurement coefficient were obtained. A candle flame was selected as the measuring object and the complete and accurate flame temperature distribution was acquired following our proposed method. The experimental results show that, compared with the temperature measurement using a single exposure time, our method can effectively avoid the measurement error caused by underexposure and overexposure, and improve the measurement accuracy. [ABSTRACT FROM AUTHOR]

The fall armyworm (FAW), native to the Americas, has rapidly invaded the whole of Southern China since January 2019. In addition, it can survive and breed in the key maize- and rice- growing area of the Yangtze River Valley. Furthermore, this pest is also likely to continue infiltrating other cropping regions in China, where food security is facing a severe threat. To understand the potential infestation area of newly-invaded FAW from the Yangtze River Valley, we simulated and predicted the possible flight pathways and range of the populations using a numerical trajectory modelling method combining meteorological data and self-powered flight behavior parameters of FAW. Our results indicate that the emigration of the first and second generations of newly-invaded FAW initiating from the Yangtze River Valley started on 20 May 2019 and ended on 30 July 2019. The spread of migratory FAW benefitted from transport on the southerly summer monsoon so that FAW emigrants from the Yangtze River Valley can reach northern China. The maize-cropping areas of Northeastern China, the Korean Peninsula and Japan are at a high risk. This study provides a basis for early warning and a broad picture of FAW migration from the Yangtze River Valley. [ABSTRACT FROM AUTHOR]

The online and continuous measurement of velocity, concentration and mass flow rate of pneumatically conveyed solid particles for the high-efficiency utilization of energy and raw materials has become increasingly significant. In this paper, an integrated instrumentation system for the velocity, concentration and mass flow rate measurement of dense phase pneumatically conveyed solid particles based on electrostatic and capacitance sensorsis developed. The electrostatic sensors are used for particle mean velocity measurement in combination with the cross-correlation technique, while the capacitance sensor with helical surface-plate electrodes, which has relatively homogeneous sensitivity distribution, is employed for the measurement of particle concentration and its capacitance is measured by an electrostatic-immune AC-based circuit. The solid mass flow rate can be further calculated from the measured velocity and concentration. The developed instrumentation system for velocity and concentration measurement is verified and calibrated on a pulley rig and through static experiments, respectively. Finally the system is evaluated with glass beads on a gravity-fed rig. The experimental results demonstrate that the system is capable of the accurate solid mass flow rate measurement, and the relative error is within -3%-8% for glass bead mass flow rates ranging from 0.13 kg/s to 0.9 kg/s.