426 research outputs found

    Development of multi-functional combine harvester with grain harvesting and straw baling

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    The decomposition and burning of straw results in serious environmental pollution, and research is needed to improve strategies for straw collection to reduce pollution. This work presents an integrated design of multi-functional rice combine harvester that allows grain harvesting and straw baling. This multi-functional combine harvester could reduce the energy consumption required for rice harvesting and simplify the process of harvesting and baling. The transmission schematic, matching parameters and the rotation speed of threshing cylinder and square baler were designed and checked. Then the evaluation of grain threshing and straw baling were tested on a transverse threshing cylinders device tes rig and straw square bales compression test rig. The test results indicated that, with a feeding rate of 3.0 kg/s, the remaining straw flow rate at the discharge outlet was only 1.22 kg/s, which indicates a variable mass threshing process by the transverse threshing cylinder. Then the optimal diameter, length and rotating speed of multi-functional combine harvester transverse threshing cylinder were 554 mm, 1590 mm, and 850 r/min, respectively. The straw bale compression rotating speed of crank compression slider and piston was 95 r/min. Field trials by the multi-functional combine harvester formed bales with height×width×length of 40×50×54-63 cm, bale mass of 22.5 to 26.0 kg and bale density 206 to 216 kg/m3. This multi-functional combine harvester could be used for stem crops (such as rice, wheat and soybean) grain harvesting and straw square baling, which could reduce labor cost and power consumption

    Strong quantum metrological limit from many-body physics

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    Surpassing the standard quantum limit and even reaching the Heisenberg limit using quantum entanglement, represents the Holy Grail of quantum metrology. However, quantum entanglement is a valuable resource that does not come without a price. The exceptional time overhead for the preparation of large-scale entangled states raises disconcerting concerns about whether the Heisenberg limit is fundamentally achievable. Here we find a universal speed limit set by the Lieb-Robinson light cone for the quantum Fisher information growth to characterize the metrological potential of quantum resource states during their preparation. Our main result establishes a strong precision limit of quantum metrology accounting for the complexity of many-body quantum resource state preparation and reveals a fundamental constraint for reaching the Heisenberg limit in a generic many-body lattice system with bounded one-site energy. It enables us to identify the essential features of quantum many-body systems that are crucial for achieving the quantum advantage of quantum metrology, and brings an interesting connection between many-body quantum dynamics and quantum metrology.Comment: 7 pages, 3 figures + supplementary information (14 pages

    Ion Exchange Membranes for Electrodialysis: A Comprehensive Review of Recent Advances

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    Electrodialysis related processes are effectively applied in desalination of sea and brackish water, waste water treatment, chemical process industry, and food and pharmaceutical industry. In this process, fundamental component is the ion exchange membrane (IEM), which allows the selective transport of ions. The evolvement of an IEM not only makes the process cleaner and energy-efficient but also recovers useful effluents that are now going to wastes. However ion-exchange membranes with better selectivity, less electrical resistance, good chemical, mechanical and thermal stability are appropriate for these processes. For the development of new IEMs, a lot of tactics have been applied in the last two decades. The intention of this paper is to briefly review synthetic aspects in the development of new ion-exchange membranes and their applications for electrodialysis related processes

    Evolution of Microstructural Characteristics of Carbonated Cement Pastes Subjected to High Temperatures Evaluated by MIP and SEM

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    The microstructural evolutions of both uncarbonated and carbonated cement pastes subjected to various high temperatures (30 degrees C, 200 degrees C, 400 degrees C, 500 degrees C, 600 degrees C, 720 degrees C, and 950 degrees C) are presented in this study by the means of mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). It was found that the thermal stabilities of uncarbonated cement pastes were significantly changed from 400 to 500 degrees C due to the decomposition of portlandite at this temperature range. More large pores and microcracks were generated from 600 to 720 degrees C, with the depolymerization of C-S-H. After carbonation, the microstructures of carbonated cement pastes remained unchanged below 500 degrees C and started to degrade at 600 degrees C, due to the decompositions of calcium carbonates and calcium modified silica gel. At 950 degrees C, both uncarbonated and carbonated cement pastes showed a loosely honeycombed microstructure, composed mainly of beta-C2S and lime. It can be concluded that carbonation improves the high-temperature resistance of cement pastes up to 500 degrees C, but this advantage is lost at temperatures over 600 degrees C

    Effects of Temperature on Corrosion Behavior of Reinforcements in Simulated Sea-Sand Concrete Pore Solution

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    The effects of temperature on the chloride-induced corrosion behavior of reinforcing steel in simulated sea-sand concrete pore solution are studied by means of linear polarization resistance. The results show that the Ecorr (corrosion potential) and icorr (corrosion current density) of the reinforcing steels are temperature and/or chloride concentration (CCl )-related parameters. A linear correlation between Ecorr and temperature and a natural logarithmic correlation between icorr and CCl are observed. It is proved that the relationship between the corrosion rate and temperature follows the Arrhenius equation, whereas the activation energy of corrosion reaction increases with the increase of CCl

    Heptacarbonyldiosmium and Hexacarbonyldiosmium: Two Highly Unsaturated Binuclear Osmium Carbonyls

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    A total of nine singlet structures for Os2(CO)7 and 15 structures (nine singlet and six triplet) for Os2(CO)6 have been found by density functional theory thereby indicating very complicated energy surfaces. The global minimum for Os2(CO)7 is a doubly carbonyl bridged structure Os2(CO)5(μ-CO)2 with an Os=Os distance of 2.67 Å suggesting a formal double bond and hence a 16-electron rather than an 18-electron configuration for one of the osmium atoms. However, at only slightly higher energy (3.2 kcal mol−1) lies an unbridged Os2(CO)7 structure with a shorter Os≡Os distance of 2.54 Å, corresponding to a formal triple bond and an 18-electron configuration for each osmium atom. The global minimum for Os2(CO)6 can be derived from that of Os2(CO)7 by removal of a carbonyl group while retaining the Os=Os double bond and the two bridging carbonyl groups. Slightly higher energy Os2(CO)6 structures at ≈3 kcal mol−1 or more above the global minimum have short Os-Os quadrupole bond distances around 2.4 Å, consistent with the formal quadruple bonds necessary to give both osmium atoms the favored 18-electron configuration. None of the 24 structures for Os2(CO)7 and Os2(CO)6 found in this work has a four-electron donor η2-μ-CO bridging carbonyl group

    Japanese Encephalitis Virus wild strain infection suppresses dendritic cells maturation and function, and causes the expansion of regulatory T cells

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    <p>Abstract</p> <p>Background</p> <p>Japanese encephalitis (JE) caused by Japanese encephalitis virus (JEV) accounts for acute illness and death. However, few studies have been conducted to unveil the potential pathogenesis mechanism of JEV. Dendritic cells (DCs) are the most prominent antigen-presenting cells (APCs) which induce dual humoral and cellular responses. Thus, the investigation of the interaction between JEV and DCs may be helpful for resolving the mechanism of viral escape from immune surveillance and JE pathogenesis.</p> <p>Results</p> <p>We examined the alterations of phenotype and function of DCs including bone marrow-derived DCs (bmDCs) <it>in vitro </it>and spleen-derived DCs (spDCs) <it>in vivo </it>due to JEV P3 wild strain infection. Our results showed that JEV P3 infected DCs <it>in vitro </it>and <it>in vivo</it>. The viral infection inhibited the expression of cell maturation surface markers (CD40, CD80 and CD83) and MHCⅠ, and impaired the ability of P3-infected DCs for activating allogeneic naïve T cells. In addition, P3 infection suppressed the expression of interferon (IFN)-α and tumor necrosis factor (TNF)-α but enhanced the production of chemokine (C-C motif) ligand 2 (CCL2) and interleukin (IL)-10 of DCs. The infected DCs expanded the population of CD4+ Foxp3+ regulatory T cell (Treg).</p> <p>Conclusion</p> <p>JEV P3 infection of DCs impaired cell maturation and T cell activation, modulated cytokine productions and expanded regulatory T cells, suggesting a possible mechanism of JE development.</p

    Learning-based real-time imaging through dynamic scattering media

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    Imaging through dynamic scattering media is one of the most challenging yet fascinating problems in optics, with applications spanning from biological detection to remote sensing. In this study, we propose a comprehensive learning-based technique that facilitates real-time, non-invasive, incoherent imaging of real-world objects through dense and dynamic scattering media. We conduct extensive experiments, demonstrating the capability of our technique to see through turbid water and natural fog. The experimental results indicate that the proposed technique surpasses existing approaches in numerous aspects and holds significant potential for imaging applications across a broad spectrum of disciplines

    Atmospheric turbulence and land - atmosphere energy transfer characteristics in the surface layer of the Northern slope of Mt. Qomolangma area : abstract

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    Based on the turbulent data collected at Quzong site, on the northern slope of Mt. Qomolangma, from April 2005 to March 2006, macro-scale turbulent statistical characteristics and land-atmosphere energy transfer before and after the onset of southwest monsoon were acquired by the eddy correlation method. It was found that Monin-Obukhov similarity theory is applicable for Mt. Qomolangma area. The relationship between normalized wind speed standard deviation and atmospheric stability, variances of normalized temperature and humidity standard deviation with atmospheric stability were simulated in the study. It was also found that energy balance components (net radiation flux, sensible heat flux, latent heat flux and soil heat flux) and surface heating filed had evident diurnal and seasonal changes. Especially under the influence of southwest monsoon, the sensible heat flux and latent heat flux in Quzong area have evident opposite changing trends. The variation characteristics of other surface parameters (surface reflectance and Bowen ratio) is very clear before and after the breakout of southwest monsoon
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