26 research outputs found
Space advanced technology demonstration satellite
The Space Advanced Technology demonstration satellite (SATech-01), a mission for low-cost space science and new technology experiments, organized by Chinese Academy of Sciences (CAS), was successfully launched into a Sun-synchronous orbit at an altitude of similar to 500 km on July 27, 2022, from the Jiuquan Satellite Launch Centre. Serving as an experimental platform for space science exploration and the demonstration of advanced common technologies in orbit, SATech-01 is equipped with 16 experimental payloads, including the solar upper transition region imager (SUTRI), the lobster eye imager for astronomy (LEIA), the high energy burst searcher (HEBS), and a High Precision Magnetic Field Measurement System based on a CPT Magnetometer (CPT). It also incorporates an imager with freeform optics, an integrated thermal imaging sensor, and a multi-functional integrated imager, etc. This paper provides an overview of SATech-01, including a technical description of the satellite and its scientific payloads, along with their on-orbit performance
Refactoring and Optimization of Bridge Dynamic Displacement Based on Ensemble Empirical Mode Decomposition
Considering the lack of precision in transforming measured micro-electro-mechanical system (MEMS) accelerometer output signals into elevation signals, this paper proposes a bridge dynamic displacement reconstruction method based on the combination of ensemble empirical mode decomposition (EEMD) and time domain integration, according to the vibration signal traits of a bridge. Through simulating bridge analog signals and verifying a vibration test bench, four bridge dynamic displacement monitoring methods were analyzed and compared. The proposed method can effectively eliminate the influence of low-frequency integral drift and high-frequency ambient noise on the integration process. Furthermore, this algorithm has better adaptability and robustness. The effectiveness of the method was verified by field experiments on highway elevated bridges
Determining charge carrier mobility in Schottky contacted single-carrier organic devices by impedance spectroscopy
Impedance spectroscopy (IS) is one of the most important methods for analyzing transport properties of semiconducting thin films. At present carrier mobility can be determined by IS methods only for Ohmic contacted single-carrier devices, which hinders the use of the IS method for determining the carrier mobility of thin films with high-lying lowest unoccupied molecular orbits or low-lying highest occupied molecular orbits. Based on the theory of space charge limited current conduction and thermionic emission at metal-organic interface, we developed a numerical IS model for single-carrier organic devices with Schottky injection contact. With the help of this model, a concise empirical formula is obtained from which the carrier mobility can be determined from the characteristic frequency of the negative differential susceptance and the Schottky energy barrier height at the injection contact
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The Unintended Impacts of Agricultural Fires: Human Capital In China
The practice of burning agricultural waste is ubiquitous around the world, yet the external human capital costs from those fires have been underexplored. Using data from the National College Entrance Examination (NCEE) and agricultural fires detected by high-resolution satellites in China during 2005 to 2011, this paper investigates the impacts of fires on cognitive performance. To address the endogeneity of agricultural fires, we differentiate upwind fires from downwind fires. We find that a one-standard-deviation increase in the difference between upwind and downwind fires during the exam decreases the total exam score by 1.42 percent of a standard deviation (or 0.6 point), and further decreases the probability of getting into first-tier universities by 0.51 percent of a standard deviation
Enhanced performance of isotype planar heterojunction photoresponsive organic field-effect transistors by using Ag source-drain electrodes
Pentacene/lead phthalocyanine (PbPc)-based isotype and fullerene /PbPc-based anisotype planar heterojunction near-infrared photoresponsive organic field-effect transistors (PhOFETs) were fabricated. We compared the performance of the isotype planar heterojunction PhOFET and the anisotype one, and dominantly investigated the effect of contact on the performance of the isotype planar heterojunction devices. The results showed that the isotype planar heterojunction device exhibits a comparable maximum photoresponsivity of 107 mA/W and a comparable maximum photo/dark current ratio of to the anisotype one ( of 109 mA/W and of ), and exhibits superior air stability to the anisotype one. Moreover, it is surprising to find that Ag source-drain electrodes replacing Au ones yield a performance enhancement in isotype PHJ devices, this is mainly because the use of Ag source-drain electrodes enhances the photo-generated exciton dissociation efficiency at the metal/PbPc interface
Variation of Fertility and Phenological Synchronization in <i>Cunninghamia lanceolata</i> Seed Orchard: Implications for Seed Production
Reproductive synchronicity between parents influences the seed production and quality in seed orchards. Our objective was to determine clonal variation in fertility and phenological synchronization, as well as their effect on seed production, in a Chinese fir (Cunninghamia lanceolata) open-pollinated seed orchard. Significant variation of female fertility and male phenological synchronization occurred in the clones. The flowering of the male was 2 days earlier than the female. The gamete contribution of female and male were unbalanced between clones (the phenological synchronization indexes (POij) were 0.000–0.585 (as female) vs. 0.000–0.385 (as male)). In general, the average POij value of as a male was lower than as a female, but the number of male flowers were significantly higher than female, indicating that the management of female flowers should be enhanced. The average POij of self-pollination was 0.298, higher than cross-pollination (0.236), indicating that there was a larger probability to selfing in the orchard. The middle phenological type possessed higher phenological synchronization indexes than early and late phenological type. Genetic control was stronger for number of female flowers (H2 = 0.277) than for male and female initial stages and flower duration (H2 = 0.193–0.239). We found a positive correlation between POij and TSW (r = 0.756), SOsc (r = 0.612), and Cp (r = 0.337), suggesting the phenological synchronization determined the seed quality and yield. Comprehensively, this study provided fertility and phenology information for management of a Chinese fir seed orchard, as well as a reference for the establishment of advanced seed orchards of conifer trees
Variation of Fertility and Phenological Synchronization in Cunninghamia lanceolata Seed Orchard: Implications for Seed Production
Reproductive synchronicity between parents influences the seed production and quality in seed orchards. Our objective was to determine clonal variation in fertility and phenological synchronization, as well as their effect on seed production, in a Chinese fir (Cunninghamia lanceolata) open-pollinated seed orchard. Significant variation of female fertility and male phenological synchronization occurred in the clones. The flowering of the male was 2 days earlier than the female. The gamete contribution of female and male were unbalanced between clones (the phenological synchronization indexes (POij) were 0.000–0.585 (as female) vs. 0.000–0.385 (as male)). In general, the average POij value of as a male was lower than as a female, but the number of male flowers were significantly higher than female, indicating that the management of female flowers should be enhanced. The average POij of self-pollination was 0.298, higher than cross-pollination (0.236), indicating that there was a larger probability to selfing in the orchard. The middle phenological type possessed higher phenological synchronization indexes than early and late phenological type. Genetic control was stronger for number of female flowers (H2 = 0.277) than for male and female initial stages and flower duration (H2 = 0.193–0.239). We found a positive correlation between POij and TSW (r = 0.756), SOsc (r = 0.612), and Cp (r = 0.337), suggesting the phenological synchronization determined the seed quality and yield. Comprehensively, this study provided fertility and phenology information for management of a Chinese fir seed orchard, as well as a reference for the establishment of advanced seed orchards of conifer trees