349 research outputs found

    Research and Practice of Blended Teaching Mode Based on Network Teaching Platform—Taking Engine Principles as an Example

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    With the development of Internet information technology, a new educational model of “Internet + education” has emerged[1],It has promoted the reform of the university teaching classroom, and the hybrid teaching mode based on the online teaching platform will also enter the university classroom. In this paper, taking the engine principle course as an example, combines the school situation, teaching situation and learning situation of our school, and builds a hybrid teaching mode based on the online teaching platform. The construction and implementation of blended teaching mode are completed through the analysis of teaching content, teaching environment, teaching situation and teaching evaluation. It breaks the traditional teaching mode of teacher’s one-man show, realizes the dominant role of students and the leading role of teachers, stimulates students’ interest in learning, improves their independent learning ability, and ensures the quality of teaching

    Integrated Hydraulic Fracture Placement and Design Optimization in Unconventional Gas Reservoirs

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    Unconventional reservoir such as tight and shale gas reservoirs has the potential of becoming the main source of cleaner energy in the 21th century. Production from these reservoirs is mainly accomplished through engineered hydraulic fracturing to generate fracture networks that provide the gas flow pathways from the rock matrix to the production wells. While hydraulic fracturing technology has progressed considerably in the last thirty years, designing the fracturing system primarily involves judgments from a team of engineers, geoscientists and geophysicists, without taking advantage of computational tools, such as numerical optimization techniques to improve short-term and long-term reservoir production. This thesis focuses on developing novel optimization algorithms that can be used to improve the design and implementation of hydraulic fracturing in a shale gas reservoir to increase production and the net present value of unconventional assets. In particular, we consider simultaneous perturbation stochastic approximation (SPSA) and Covariance Matrix Adaptation - Evolution Strategy (CMA-ES) algorithms, which are proven very efficient in finding nearly optimal solutions. We show that with a judicious choice of control variables (continuous or discrete) we can obtain efficient algorithms for performing hydraulic fracture optimization in unconventional reservoirs. To achieve this, the hydraulic fracture production optimization problem is divided into two aspects: fracture stages placement optimization with fix stage numbers and unknown stage numbers. After check the parameters of fracture model that could be used to simulate future reservoir behavior with a higher degree of confidence, the fracture stages optimization is scheduling the fracturing sequence, and adjusting the fracture stages intensity at different locations, which is similar to well placement problem. In addition to the detailed investigation of the new optimization technique, uncertainty quantification of reservoir properties and its implications on the optimization workflow is also considered in the shale gas reservoir model. Taking into account that shale gas reservoirs are highly heterogeneous systems, stochastic optimization methods are the most suitable framework for hydraulic fracture stages placement

    Induction of Cellular Immune Response by DNA Vaccine Coexpressing E. acervulina 3-1E Gene and Mature CHIl-15 Gene

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    We previously reported that the chimeric DNA vaccine pcDNA-3-1E-linker-mChIL-15, fused through linking Eimeria acervulina 3-1E encoding gene and mature chicken IL-15 (mChIL-15) gene with four flexible amino acid SPGS, could significantly offer protection against homologous challenge. In the present study, the induction of cellular immune response induced by the chimeric DNA vaccine pcDNA-3-1E-linker-mChIL-15 was investigated. Spleen lymphocyte subpopulations were characterized by flow cytometric analysis. The spleen lymphocyte proliferation assays were measured by 3-[4,5-dimethylthiazol-2-y1]-2,5-diphenyltetrazolium bromide (MTT) method. The mRNA profiles of ChIL-2 and ChIFN-γ in spleen were characterized by means of real-time PCR. Chickens immunized with pcDNA-3-1E-linker-mChIL-15 exhibited significant upregulated level of ChIL-2 and ChIFN-γ transcripts in spleen following two immunizations compared with chickens in other groups (P < 0.01). In comparison with pcDNA3.1-immunized and control groups, lymphocyte proliferation, percentage of CD8α+ cell, and levels of ChIL-2 and ChIFN-γ transcripts in the group immunized with pcDNA-3-1E-linker-mChIL-15 were significantly increased on day 6 following challenge (P < 0.05, P < 0.01, and P < 0.01, resp.). Our data suggested that the fusion antigen 3-1E-linker-mChIL-15 could be a potential candidate for E. acervulina vaccine development

    Motion Detection in High Resolution Enhancement

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    Shifted Superposition (SSPOS) is a resolution enhancement methodwhere apparent high-resolution content is displayed using a lowresolutionprojection system with an opto-mechanical shifter. WhileSSPOS-enhanced projectors have been showing promising resultsin still images, they still suffer from motion artifacts in video contents.Motivated by this, we present a novel approach to apparentprojector resolution enhancement for videos via motion-basedblurring module. We propose the use of a motion detection moduleand a blurring module to compensate for both SSPOS-resulted andnatural motion artifacts in the video content. To accomplish this,we combine both local and global motion estimation algorithms togenerate accurate dense flow fields. The detected motion regionsare enhanced using directional Gaussian filters. Preliminary resultsshow that the proposed method can produce accurate densemotion vectors and significantly reduce the artifacts in videos

    MO-VLN: A Multi-Task Benchmark for Open-set Zero-Shot Vision-and-Language Navigation

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    Given a natural language, a general robot has to comprehend the instruction and find the target object or location based on visual observations even in unexplored environments. Most agents rely on massive diverse training data to achieve better generalization, which requires expensive labor. These agents often focus on common objects and fewer tasks, thus are not intelligent enough to handle different types of instructions. To facilitate research in open-set vision-and-language navigation, we propose a benchmark named MO-VLN, aiming at testing the effectiveness and generalization of the agent in the multi-task setting. First, we develop a 3D simulator rendered by realistic scenarios using Unreal Engine 5, containing more realistic lights and details. The simulator contains three scenes, i.e., cafe, restaurant, and nursing house, of high value in the industry. Besides, our simulator involves multiple uncommon objects, such as takeaway cup and medical adhesive tape, which are more complicated compared with existing environments. Inspired by the recent success of large language models (e.g., ChatGPT, Vicuna), we construct diverse high-quality data of instruction type without human annotation. Our benchmark MO-VLN provides four tasks: 1) goal-conditioned navigation given a specific object category (e.g., "fork"); 2) goal-conditioned navigation given simple instructions (e.g., "Search for and move towards a tennis ball"); 3) step-by-step instruction following; 4) finding abstract object based on high-level instruction (e.g., "I am thirsty").Comment: 18 page

    Shaking Table Test and Time-history Analysis of High-rise Diagrid Tube Structure

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    As a new type of high-rise building structure system, diagridtube in tube structure is increasingly applied in high-rise building.Guangzhou West tower is the first high-rise diagrid tube intube structure in China. To study seismic performance of thestructure, elastic time-history analysis and shaking table testwere conducted. The results of elastic time-history analysis andshaking table test were in a good agreement, which verified thevalidity of the elastic time-history analysis. Dynamic characteristicsand responses of the model structure’s acceleration,displacement and strain under different intensity earthquakeaction were obtained through analysis and test. Dynamicresponses of prototype structure were deduced based on similaritylaw and shaking table test results. Research shows thatdiagrid tube structure has a small deformation under earthquakeactions; the main vibration mode is translation, whiletorsional effect is not obvious; whiplash effect has less influenceon the structure; diagrid members, diagrid nodes andshear walls at the bottom of the structure are weak parts

    Quercetin and Bornyl Acetate Regulate T-Lymphocyte Subsets and INF-γ/IL-4 Ratio In Utero in Pregnant Mice

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    The objective of this study is to investigate the antiabortive effects of Quercetin and Bornvl Acetate and their immunological modulation at maternal-fetal interface. Lipopolysaccharide (LPS) was injected via tail vein to induce abortion in mice which received Quercetin and Bornvl Acetate at days 4–7 of gestation. Uterine CD4+/CD8+ T lymphocytes and IFN-γ/IL-4 of each group (n = 10) were detected by immunohistochemistry and enzyme-linked immunosorbent assay, respectively. The ratio of CD4+/CD8+ increased significantly (P < .01) in the uterus of LPS-induced abortion mice. In the Quercetin and Bornvl Acetate pretreated mice followed by LPS administration, the ratio of CD4+/CD8+ dropped to 0.562 ± 0.021, lower than that of LPS-abortion group (P < .01). The mean value of IFN-γ/IL-4 in LPS-treated mice was 0.310 ± 0.066, higher than that of Quercetin and Bornyl Acetate group. The results indicate that Quercetin and Bornyl Acetate have an antiabortive effect through modulation of immunological balance at maternal-fetal interface

    Organic mulching promotes soil organic carbon accumulation to deep soil layer in an urban plantation forest

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    Abstract Background Soil organic carbon (SOC) is important for soil quality and fertility in forest ecosystems. Labile SOC fractions are sensitive to environmental changes, which reflect the impact of short-term internal and external management measures on the soil carbon pool. Organic mulching (OM) alters the soil environment and promotes plant growth. However, little is known about the responses of SOC fractions in rhizosphere or bulk soil to OM in urban forests and its correlation with carbon composition in plants. Methods A one-year field experiment with four treatments (OM at 0, 5, 10, and 20 cm thicknesses) was conducted in a 15-year-old Ligustrum lucidum plantation. Changes in the SOC fractions in the rhizosphere and bulk soil; the carbon content in the plant fine roots, leaves, and organic mulch; and several soil physicochemical properties were measured. The relationships between SOC fractions and the measured variables were analysed. Results The OM treatments had no significant effect on the SOC fractions, except for the dissolved organic carbon (DOC). OM promoted the movement of SOC to deeper soil because of the increased carbon content in fine roots of subsoil. There were significant correlations between DOC and microbial biomass carbon and SOC and easily oxidised organic carbon. The OM had a greater effect on organic carbon fractions in the bulk soil than in the rhizosphere. The thinnest (5 cm) mulching layers showed the most rapid carbon decomposition over time. The time after OM had the greatest effect on the SOC fractions, followed by soil layer. Conclusions The frequent addition of small amounts of organic mulch increased SOC accumulation in the present study. OM is a potential management model to enhance soil organic matter storage for maintaining urban forest productivity
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