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  • 1
    In: Photonics, MDPI AG, Vol. 8, No. 6 ( 2021-05-22), p. 178-
    Abstract: In this study, both theoretical analysis and experimental validation are carried out for 3D surface measurement under different indoor/outdoor environmental conditions via combining the projected laser-beam-based sinusoidal optical signal, the optical filtering technique, and the single-shot approach based on Fourier transform profilometry. The designed optical signal generator used in this work is capable of ensuring that the projected fringe pattern is monochromatic, higher-contrast, time-invariant, and truly sinusoidal. The proposed and developed optical setup of 3D surface measurement is portable and is used for in-situ experiments of 3D surface measurements that have been carried out under different sunlight illuminations. The experimental results indicate that accurate reconstructions of measured objects with even or varying surface reflectivity can be obtained under windy conditions and strong environmental illuminations such as the background illuminance of 5600–35,000 Lux. The generated fringe-pattern signal is not sensitive to vibrations from environmental influences including the effects of the wind, which has overcome the outdoor-measurement restrictions of the traditional interferometric system and the profilometry approaches based on phase-shifting methods.
    Type of Medium: Online Resource
    ISSN: 2304-6732
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2770002-1
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  • 2
    In: Micromachines, MDPI AG, Vol. 10, No. 2 ( 2019-02-14), p. 126-
    Abstract: This paper analyzes the effect of the anisotropy of single crystal silicon on the frequency split of the vibrating ring gyroscope, operated in the n = 2 wineglass mode. Firstly, the elastic properties including elastic matrices and orthotropic elasticity values of (100) and (111) silicon wafers were calculated using the direction cosines of transformed coordinate systems. The (111) wafer was found to be in-plane isotropic. Then, the frequency splits of the n = 2 mode ring gyroscopes of two wafers were simulated using the calculated elastic properties. The simulation results show that the frequency split of the (100) ring gyroscope is far larger than that of the (111) ring gyroscope. Finally, experimental verifications were carried out on the micro-gyroscopes fabricated using deep dry silicon on glass technology. The experimental results are sufficiently in agreement with those of the simulation. Although the single crystal silicon is anisotropic, all the results show that compared with the (100) ring gyroscope, the frequency split of the ring gyroscope fabricated using the (111) wafer is less affected by the crystal direction, which demonstrates that the (111) wafer is more suitable for use in silicon ring gyroscopes as it is possible to get a lower frequency split.
    Type of Medium: Online Resource
    ISSN: 2072-666X
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2620864-7
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  • 3
    In: Sustainability, MDPI AG, Vol. 15, No. 15 ( 2023-07-28), p. 11714-
    Abstract: Surveys show that rivers worldwide transport an annual sediment load of 15 billion tons into the sea, with the Yellow River Basin alone contributing 1.6 billion tons of sand. Therefore, understanding the wind and sand dynamics in the Yellow River Basin is crucial to ensuring the safe development of similar basins across China and the world. This study investigated the midstream wind and sand area of the Xiliugou tributary, a part of the upper Yellow River. Sand transport flux at 0–50 cm height on various underlying surfaces of the basin was measured using a stepped sand collector combined with an anemometer. Then, the amounts of wind and sand entering the Yellow River were estimated using a function model based on the measured factors. The particle size composition of wind-eroded sand was further analyzed to better understand the principles of wind and sand erosion and accumulation in the basin. The results show that the sand transport flux per unit area varies significantly across different underlying surfaces. The vertical change in sand transport rate on the basin’s surface shows that the total sand transport rate is an exponential function of wind speed. Based on this relationship, the total annual average wind and sand entering the Yellow River basin via the Xiliugou tributary was estimated to be approximately 8.09 × 105 t. Controlled by the basin’s unique geography, sand source, and human activities, the particle size composition of wind-eroded sand distinctly differs between the east and west sides of the river channel, exhibiting a “wind-blown mud and water-washed sand” pattern. The Yellow River basin still faces significant ecological security hazards. Understanding the coupling relationship between desert-basin-sand and wind is the foundation for effectively controlling wind and sand flow into the Yellow River Basin.
    Type of Medium: Online Resource
    ISSN: 2071-1050
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2518383-7
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  • 4
    Online Resource
    Online Resource
    MDPI AG ; 2021
    In:  Micromachines Vol. 12, No. 4 ( 2021-03-25), p. 353-
    In: Micromachines, MDPI AG, Vol. 12, No. 4 ( 2021-03-25), p. 353-
    Abstract: Energy harvesting using piezoceramic has drawn a lot of attention in recent years. Its potential usage in microelectromechanical systems is starting to become a reality thanks to the development of an integrated circuit. An accurate equivalent circuit of piezoceramic is important in energy harvesting and the sensing system. A piezoceramic is always considered to be a current source according to empirical testing, instead of the derivation from its piezoelectric characteristics, which lacks accuracy under complicated mechanical excitation situations. In this study, a new current output model is developed to accurately estimate its value under various kinds of stimulation. Considering the frequency, amplitude and preload variation imposed on a piezoceramic, the multivariate model parameters are obtained in relation to piezo coefficients. Using this model, the current output could be easily calculated without experimental testing in order to quickly estimate the output power in energy harvesting whatever its geometric shape and the various excitations.
    Type of Medium: Online Resource
    ISSN: 2072-666X
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2620864-7
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  • 5
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 23, No. 19 ( 2022-09-25), p. 11288-
    Abstract: Glutathione S-transferases (GSTs) play an essential role in plant cell detoxification and secondary metabolism. However, their accurate functions in the growth and response to abiotic stress in woody plants are still largely unknown. In this work, a Phi class Glutathione S-transferase encoding gene PtGSTF1 was isolated from poplar (P. trichocarpa), and its biological functions in the regulation of biomass production and salt tolerance were investigated in transgenic poplar. PtGSTF1 was ubiquitously expressed in various tissues and organs, with a predominant expression in leaves and inducible expression by salt stress. Transgenic poplar overexpressing PtGSTF1 showed improved shoot growth, wood formation and improved salt tolerance, consistent with the increased xylem cell number and size under normal condition, and the optimized Na+ and K+ homeostasis and strengthened reactive oxygen species scavenging during salt stress. Further transcriptome analyses demonstrated that the expressions of genes related to hydrolase, cell wall modification, ion homeostasis and ROS scavenging were up- or down-regulated in transgenic plants. Our findings imply that PtGSTF1 improves both biomass production and salt tolerance through regulating hydrolase activity, cell wall modification, ion homeostasis and ROS scavenging in transgenic poplar, and that it can be considered as a useful gene candidate for the genetic breeding of new tree varieties with improved growth under salt stress conditions.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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  • 6
    Online Resource
    Online Resource
    MDPI AG ; 2021
    In:  Molecules Vol. 26, No. 20 ( 2021-10-14), p. 6219-
    In: Molecules, MDPI AG, Vol. 26, No. 20 ( 2021-10-14), p. 6219-
    Abstract: The unique fruity aroma of strawberries, a popular fruit of high economic value, is closely related to all the volatile organic compounds (VOCs) contained within them. Despite extensive studies on the identification of VOCs in strawberries, systematic studies on fruit-aroma-related VOCs are few, resulting in a lack of effective standards for accurately distinguishing aroma types. In the present study, solid-phase micro extraction and gas chromatography–mass spectrometry were used to analyze and identify VOCs in the ripe fruit of each of the 16 strawberry varieties at home and abroad and to explore their characteristic aroma components and the classification of such varieties by aroma type. The results suggested remarkable variations in the types and contents of VOCs in different strawberry varieties, of which esters were dominant. The principal volatile components, consisting of four esters, three alcohols, one aldehyde, and one ketone, in 16 strawberry varieties were detected based on the absolute and relative contents of VOCs in the fruit. The characteristic aroma components in strawberries, containing nine esters, six aldehydes, and one alcohol, were determined based on the aroma values of different VOCs, and the characteristic aroma components were divided into five types further based on aroma descriptions. Sixteen strawberry varieties were finally divided into four aroma types, namely, peachy, pineapple, fruity, and floral, based on the contributions of different types. The results provided a basis and standard for classifying strawberries by aroma type, studying the hereditary regularity of the fruity aroma of strawberries, and improving aroma quality.
    Type of Medium: Online Resource
    ISSN: 1420-3049
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2008644-1
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  • 7
    In: Agronomy, MDPI AG, Vol. 12, No. 12 ( 2022-11-24), p. 2943-
    Abstract: Improving water use efficiency is essential for the advancement of agricultural production, particularly in arid and semiarid regions. Two-year field experiments were conducted to study the effects of ridge–furrow (RF) and flat planting (FP) plastic film mulching combined with five different nitrogen (N) fertilizers, N1 (KNO3), the nitrate (NO3−)/ammonium (NH4+) mixtures with different pure nitrogen ratios N2 (1:1), N3 (1:3), and N4 (3:1), and the control N5 (urea) on maize dry matter accumulation, soil water content, grain yield, water use efficiency (WUE), and N partial factor productivity. Our results showed that RF and N4 were more efficient than FP for increasing maize grain yield, WUE, and nitrogen partial factor productivity, and there was a significant interaction for cultivation practices × N formulation. RF and 3:1 NO3−/NH4+ significantly increased grain yield by 14.73% and 13.15%, and 20.07% and 24.14% in 2016 and 2017, respectively, compared to FP and nitrate only. RFN4 produced the highest grain yield in 2016 and 2017 due to the highest dry matter accumulation at filling and physiological maturity stage, ear rows per spike, and row grains per row. Over two growing seasons, the WUE and N partial factor productivity under RFN4 were 18.75% and 29.17% more on average than those of other treatments. Therefore, RFN4 is an effective planting system for increasing the simultaneity of grain yield and WUE for maize production in rain-fed agriculture.
    Type of Medium: Online Resource
    ISSN: 2073-4395
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2607043-1
    SSG: 23
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  • 8
    In: Aerospace, MDPI AG, Vol. 10, No. 9 ( 2023-09-13), p. 800-
    Abstract: The slow regression rate induced by the high pyrolysis difficulty has limited the application and development of hydroxyl-terminated polybutadiene (HTPB)-based fuels in hybrid rocket propulsion. Nickel oxide (NiO) shows the possibility of increasing the regression rate of HTPB-based fuels by catalyzing the pyrolysis process of the polymer matrix in our previous investigation; hence, this paper studies the NiO particles in the thermal decomposition and combustion of HTPB fuel grains. The DSC/TG test shows that NiO can intensely decrease the thermal stability of HTPB, and the catalytic effect of NiO is mainly reflected in the final decomposition stages of polybutadiene components. 5 wt% NiO enhances the regression rate by 19.4% and 13.7% under an oxygen mass flux of 50 kg/m2s and 150 kg/m2s, respectively. Further investigation shows that NiO particles will also cause the reduction of combustion heat and the agglomeration at the regressing surface while catalyzing the pyrolysis process, improving the thermal conductivity, and promoting the radiative heat transfer of the HTPB-based fuels; thus, more NiO additive (5 wt% 〈 [NiO] ≤ 10 wt%) does not lead to a faster regression rate in HTPB-based fuels. This study demonstrates the catalytic effect of NiO on the polymer matrix for HTPB-based fuels, showing the attractive application prospects of this additive in HTPB-containing fuel grains.
    Type of Medium: Online Resource
    ISSN: 2226-4310
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2756091-0
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  • 9
    In: Genes, MDPI AG, Vol. 12, No. 4 ( 2021-04-05), p. 530-
    Abstract: Fragaria × ananassa Duch, which among the youngest fruit crops, comprises many popular cultivars that are famous for their favored color and aroma. The regulation roles of AP2/ERF (APETALA2/ethylene-responsive element-binding factor) transcription factors in fruit flavor and color regulation have been studied in several fruit crops. The AP2 family of strawberry, which was ignored in recent AP2/ERF identification studies, was explored in this study. A total of 64 FaAP2 (Fragaria × ananassa AP2) transcription factors belonging to the euAP2, euANT (AINTEGUMENTA), and baselANT groups were identified with canonical insertion motifs in two AP2 domains. The motif identification illustrated that motifs 1, 5, and 2 indicated a corresponding AP2 domain repeat 1 with a linker region, and motifs 6, 4, 3 indicated a corresponding AP2 domain repeat 2, all of which were highly conserved. By synteny analysis, FaAP2 paralogs were identified in each sub-genome, and FaAP2 gene duplication and loss explained the unequal AP2 loci of sub-genomes. The expression profile in three cultivars indicated that six FaAP2 paralogs—four WRI (WRINKLED) gene homologs and two AP2 gene homologs—were candidate regulators of red fruit color and/or special fruit aroma. All these finds provide a basis for further investigations into role of AP2 in fruit color and aroma and would be helpful in the targeted selection of strawberry fruit quality to improve breeding.
    Type of Medium: Online Resource
    ISSN: 2073-4425
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2527218-4
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  • 10
    In: Genes, MDPI AG, Vol. 14, No. 1 ( 2022-12-25), p. 68-
    Abstract: The cultivated strawberry (Fragaria × ananassa Duch.) is an important horticultural crop. The economic values of strawberry cultivars are decided by their fruit qualities including taste, color and aroma. The important role of MYB transcription factors in fruit quality regulation is recognized increasingly with the identification of MYB genes involved in metabolism. A total of 407 MYB genes of F. × ananassa (FaMYBs) were identified in the genome-wide scale and named according to subgenome locations. The 407 FaMYBs were clustered into 36 groups based on phylogenetic analysis. According to synteny analysis, whole genome duplication and segmental duplication contributed over 90% of the expansion of the FaMYBs family. A total of 101 FaMYB loci with 1–6 alleles were identified by the homologous gene groups on homologous chromosomes. The differentially expressed FaMYB profiles of three cultivars with different fruit quality and fruit ripe processes provided the 8 candidate loci involved in fruit quality regulation. In this experiment, 7, 5, and 4 FaMYBs were screeded as candidate genes involved in the regulation of metabolism/transportation of anthocyanins, sugars or organic acids and 4-hydroxy-2, 5-dimethyl-3(2H)-furanone, respectively. These results pointed out the key FaMYBs for further functional analysis of gene regulation of strawberry fruit quality and would be helpful in the clarification on ofe roles of MYBs in the metabolism of fruit crops.
    Type of Medium: Online Resource
    ISSN: 2073-4425
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2527218-4
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