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  • MDPI AG  (32)
  • 2020-2024  (32)
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  • MDPI AG  (32)
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  • 2020-2024  (32)
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  • 1
    Online Resource
    Online Resource
    Thermal Process of Rock Crystal: Cause of Infrared Absorption Band at 3585 cm−1
    MDPI AG ; 2021
    In:  Crystals Vol. 11, No. 9 ( 2021-09-06), p. 1083-
    Details
    In: Crystals, MDPI AG, Vol. 11, No. 9 ( 2021-09-06), p. 1083-
    Abstract: Synthetic rock crystals often show a typical infrared (IR) absorption band at 3585 cm−1. However, the authors recently found this band in a natural rock crystal with blue coating. The origin of this IR band is controversial as yet. In this paper, the infrared spectra of several natural and synthetic rock crystal samples which were heated to 673 K and 1073 K were measured after these samples returned to room temperature. Comparing the infrared spectra of samples before and after heating, we found the absorption band at 3585 cm−1 was induced by the thermal process, which indicates that this band cannot be used as diagnostic evidence for synthetic rock crystal alone. In addition, the LiOH bands decreased while AlOH bands increased upon thermal processing. And the negative correlation between the LiOH bands and the 3585 cm−1 band was also distinct. The above results reveal that the thermal process destroyed the LiOH defects, leading to the formation of a new AlLi defect. And the isolated OH− defect inside dislocations generated upon thermal processing is considered to be the exact cause of the 3585 cm−1 band.
    Type of Medium: Online Resource
    ISSN: 2073-4352
    URL: Article
    DOI: 10.3390/cryst11091083
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2661516-2
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  • 2
    Online Resource
    Online Resource
    SGCNCMI: A New Model Combining Multi-Modal Information to Predict circRNA-Related miRNAs, Diseases and Genes
    MDPI AG ; 2022
    In:  Biology Vol. 11, No. 9 ( 2022-09-13), p. 1350-
    Details
    In: Biology, MDPI AG, Vol. 11, No. 9 ( 2022-09-13), p. 1350-
    Abstract: Computational prediction of miRNAs, diseases, and genes associated with circRNAs has important implications for circRNA research, as well as provides a reference for wet experiments to save costs and time. In this study, SGCNCMI, a computational model combining multimodal information and graph convolutional neural networks, combines node similarity to form node information and then predicts associated nodes using GCN with a distributive contribution mechanism. The model can be used not only to predict the molecular level of circRNA–miRNA interactions but also to predict circRNA–cancer and circRNA–gene associations. The AUCs of circRNA—miRNA, circRNA–disease, and circRNA–gene associations in the five-fold cross-validation experiment of SGCNCMI is 89.42%, 84.18%, and 82.44%, respectively. SGCNCMI is one of the few models in this field and achieved the best results. In addition, in our case study, six of the top ten relationship pairs with the highest prediction scores were verified in PubMed.
    Type of Medium: Online Resource
    ISSN: 2079-7737
    URL: Article
    DOI: 10.3390/biology11091350
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2661517-4
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  • 3
    Online Resource
    Online Resource
    Full Factorial Simulation Test Analysis and I-GA Based Piecewise Model Comparison for Efficiency Characteristics of Hydro Mechanical CVT
    MDPI AG ; 2022
    In:  Machines Vol. 10, No. 5 ( 2022-05-10), p. 358-
    Details
    In: Machines, MDPI AG, Vol. 10, No. 5 ( 2022-05-10), p. 358-
    Abstract: The hydro-mechanical continuously variable transmission (HMCVT) has complicated transmission characteristics. To analyze the influences of various factors on HMCVT’s efficiency characteristics and build a more precise HMCVT efficiency characteristic model, the paper conducted a full factorial simulation test for and a modeling study on a novel five-stage HMCVT’s efficiency characteristics. The full factorial test considered four factors with a total of 160 groups of test samples and used a range analysis method. Moreover, we proposed a piecewise modeling method for HMCVT efficiency characteristics based on the improved genetic algorithm (I-GA) and compared the precision of seven models. Research results showed that the working stage with the power output from the planet carrier had relatively higher efficiency. The variable pump’s displacement ratio had the greatest influence, and the HMCVT’s efficiency characteristics presented two variation laws with the boundary that the displacement ratio is 0. The load power and the engine speed showed a positive correlation and a negative correlation with the efficiency characteristics, respectively, and the influences decreased as the factor values increased. The modeling method proposed had high modeling precision and the mean absolute percentage error (MAPE) of seven models was in the range of 1.6884~3.1375%. The estimation precision greatly could be improved (the MAPE reduced by 7.7024% and the R2 increased by 9.2943%) by introducing the first-order term of engine speed on the basis of a two-factor model (in which the factors were the displacement ratio and the load power). The paper aimed to offer direct reference information on parameters of the mechanical design and control strategy development of HMCVT from an energy-saving perspective in the design stage.
    Type of Medium: Online Resource
    ISSN: 2075-1702
    URL: Article
    DOI: 10.3390/machines10050358
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2704328-9
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  • 4
    Online Resource
    Online Resource
    Optimization Design Based on I-GA and Simulation Test Verification of 5-Stage Hydraulic Mechanical Continuously Variable Transmission Used for Tractor
    MDPI AG ; 2022
    In:  Agriculture Vol. 12, No. 6 ( 2022-06-02), p. 807-
    Details
    In: Agriculture, MDPI AG, Vol. 12, No. 6 ( 2022-06-02), p. 807-
    Abstract: To improve the characteristics of a tractor power transmission system, make the transmission system not only meet the geometric principle but also meet the working speed requirements of the tractor, realize the continuous adjustment of the speed ratio, and solve the power interruption caused by the change of speed ratio. This paper not only proposes a new type of five-stage hydraulic mechanical continuously variable transmission (HMCVT), but also proposes a geometric design method based on I-GA. In this paper, the intersection position of each working section is introduced in the optimization design process, and six wet clutches, one brake and two planetary rows are used to achieve a flexible geometric design. The results show that the HMCVT proposed in this paper can effectively match the required speed of the tractor. After optimization, the transmission ratio characteristics are consistent with the target characteristics (the average error is about 3.27% and the common ratio is about 1.81); the simulation results based on Simulation X are highly consistent with the theoretical design values (the MAPE of 36 simulation experiments is about 0.72%); and the maximum speed of the tractor is 41.62 km/h. The proposed HMCVT design scheme and optimization design method provide a direct basis for the research and development of the composite power transmission system of tractors or other vehicles and agricultural machinery.
    Type of Medium: Online Resource
    ISSN: 2077-0472
    URL: Article
    DOI: 10.3390/agriculture12060807
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2651678-0
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  • 5
    Online Resource
    Online Resource
    Study on the Stress Distribution and Stability Control of Surrounding Rock of Reserved Roadway with Hard Roof
    MDPI AG ; 2023
    In:  Sustainability Vol. 15, No. 19 ( 2023-09-23), p. 14111-
    Details
    In: Sustainability, MDPI AG, Vol. 15, No. 19 ( 2023-09-23), p. 14111-
    Abstract: According to field observation and theoretical analysis, the failure of the 1523103 reserved roadway is mainly affected by the lateral support pressure, rock mass strength, and support mode. With the mining of the 152309 working face, the lateral pressure of coal pillars on both sides of the reserved roadway increases, and since the lithology of the two sides and the floor of the roadway is weak, the reserved roadway experiences spalling and floor heave. Through numerical simulation, the distribution law of surrounding rock stress and the displacement of surrounding rock are obtained after the roof cutting and pressure relief of the reserved roadway with hard roof. According to the cause of surrounding rock failure of a reserved roadway, the combined control technology of roof cutting and pressure relief, grouting anchor cable support, and bolt support is put forward. After cutting the roof and releasing the pressure on the working face, the lateral support pressure of the two sides of the roadway is significantly reduced, the deformation of the two sides of the roadway is small, the maximum shrinkage rate of the section is reduced from 70% to 11%, and the deformation of the surrounding rock of the 1523103 reserved roadway is effectively controlled. The successful control of the surrounding rock in the 1523103 tunnel reduces the number of coal pillars to be installed, improves the coal extraction rate, and is conducive to the sustainable utilization of limited natural resources and the sustainable development of the coal industry.
    Type of Medium: Online Resource
    ISSN: 2071-1050
    URL: Article
    DOI: 10.3390/su151914111
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2518383-7
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  • 6
    Online Resource
    Online Resource
    Laboratory Evaluation of the Permeability Durability of Utilization of Oil Shale Waste as Fine Aggregate in Open Grade Friction Course in Seasonal Frozen Regions
    MDPI AG ; 2020
    In:  Applied Sciences Vol. 10, No. 1 ( 2020-01-06), p. 419-
    Details
    In: Applied Sciences, MDPI AG, Vol. 10, No. 1 ( 2020-01-06), p. 419-
    Abstract: Open graded friction course (OGFC), as a highly permeable mixture, has the characteristics of good friction and splash-and-spray reduction during rainstorms. The limitations of the use of such mixtures include the fact that they are affected by poor durability, including strength and permeability durability issues. In a previous study, oil shale waste, as a fine aggregate in the mixture (with a particle size less than 4.75 mm), could effectively improve the overall properties of OGFC, but the permeability durability was not clear. Thus, a comprehensive investigation of the permeability durability of oil shale waste as a fine aggregate is essential to achieving a better understanding in order to promote its engineering application. In this paper, the long-term permeability when using oil shale waste as a fine aggregate in OGFC was systematically investigated based on a self-developed laboratory physical clogging procedure. The test results illustrated the effectiveness of the utilization of oil shale waste as a fine aggregate in terms of permeability durability. A comprehensive index of the clogging coefficient containing mass, porosity and permeability coefficient was proposed based on gray relation entropy theory, the physical clogging model of COF-OGFC (OGFC containing oil shale waste filler) was established and the clogging speed of COF-OGFC was quantified based on the Mistcherlich growth model. The analysis showed that there is an essential difference in the clogging behavior of permeable pavement in the spring and summer. The maximum clogging degree of the permeable pavement in summer is about 40% higher than that in spring, while the clogging rate is much lower than in the spring, at only about 14%, which indicates that the clogging behavior of permeable asphalt pavement in spring is mostly in the rapid clogging mode, and that in summer is mostly in a slow deposition clogging mode. Moreover, the test results showed that the most important influences on the spring clogging behavior of COF-OGFC were the sandy clogging materials and particle sizes ranging from 150 μm to 1180 μm, which can be used to provide a reference for the design of anti-slip sand.
    Type of Medium: Online Resource
    ISSN: 2076-3417
    URL: Article
    DOI: 10.3390/app10010419
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2704225-X
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  • 7
    Online Resource
    Online Resource
    Wide-Gap Brazing of K417G Alloy Assisted by In Situ Precipitation of M3B2 Boride Particles
    MDPI AG ; 2020
    In:  Materials Vol. 13, No. 14 ( 2020-07-14), p. 3140-
    Details
    In: Materials, MDPI AG, Vol. 13, No. 14 ( 2020-07-14), p. 3140-
    Abstract: In this study, K417G Ni-based superalloy with a 20-mm gap was successfully bonded at 1200 °C using powder metallurgy with a powder mixture. The results indicated that the microstructure and mechanical properties of the as-bonded alloy were highly dependent on the brazing time (15–45 min), mainly due to the precipitation and distribution characteristics of M3B2 boride particles. Specifically, alloy brazed for 30 min exhibited desirable mechanical properties, such as a high tensile ultimate strength of 971 MPa and an elongation at fracture of 6.5% at room temperature, exceeding the balance value (935 MPa) of the base metal. The excellent strength and plasticity were mainly due to coherent strengthening and dispersion strengthening of the in situ spherical and equiaxed M3B2 boride particles in the γ + γ′ matrix. In addition, the disappearance of dendrites and the homogenization of the microstructure are other factors that cannot be excluded. This powder metallurgy technique, which can avoid the eutectic transformation of traditional brazing, provides a new effective method for wide-gap repair of alloy materials.
    Type of Medium: Online Resource
    ISSN: 1996-1944
    URL: Article
    DOI: 10.3390/ma13143140
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2487261-1
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  • 8
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    Online Resource
    Transcriptomic Analysis of Yunwu Tribute Tea Leaves under Cold Stress
    MDPI AG ; 2023
    In:  Current Issues in Molecular Biology Vol. 45, No. 1 ( 2023-01-13), p. 699-720
    Details
    In: Current Issues in Molecular Biology, MDPI AG, Vol. 45, No. 1 ( 2023-01-13), p. 699-720
    Abstract: Background: Cold stress usually occurs in winter and is one of the most significant environmental factors restricting the growth of the tea plant as well as its geographical distribution. Objective: It is necessary to identify the physiological and molecular mechanisms of plants under cold stress so that cold-tolerant crop varieties can be cultivated to limit production losses. At the same time, this would allow the crop planting area to be expanded, hence improving the economic benefits. Methods: In this study, the transcriptome data of Yunwu Tribute Tea under cold conditions were obtained using the Illumina HiSeq platform. By analyzing changes in transcriptome data associated with the antioxidant enzyme system, plant hormone signal transduction, proline and tyrosine metabolism pathways, and transcription factors, the molecular mechanisms involved in Yunwu Tribute Tea under cold stress were investigated. Results: In this study, Illumina HiSeq technology was applied to investigate the cold-tolerance mechanism. For this purpose, cDNA libraries were obtained from two groups of samples, namely the cold-treated group (DW) and the control group (CK). A total of 185,973 unigenes were produced from 511,987 assembled transcripts; among these, 16,020 differentially expressed genes (DEGs) (corrected p-value 〈 0.01, |log2(fold change)| 〉 3), including 9606 up-regulated and 6414 down-regulated genes, were obtained. Moreover, the antioxidant enzyme system, plant hormone signal transduction, proline and tyrosine metabolism pathways, and transcription factors were analyzed; based on these results, a series of candidate genes related to cold stress were screened out and discussed. The physiological indexes related to the low-temperature response were tested, along with five DEGs which were validated by quantitative real-time PCR. Conclusions: Differential gene expression analysis has confirmed that substantial cold-responsive genes are related to the antioxidant enzyme system, plant hormone signal transduction, proline metabolism pathway, tyrosine metabolism pathway, and transcription factors.
    Type of Medium: Online Resource
    ISSN: 1467-3045
    URL: Article
    DOI: 10.3390/cimb45010047
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2090836-2
    SSG: 12
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  • 9
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    Research Progress on Intrinsically Conductive Polymers and Conductive Polymer-Based Composites for Electromagnetic Shielding
    MDPI AG ; 2023
    In:  Molecules Vol. 28, No. 22 ( 2023-11-17), p. 7647-
    Details
    In: Molecules, MDPI AG, Vol. 28, No. 22 ( 2023-11-17), p. 7647-
    Abstract: Electromagnetic shielding materials are special materials that can effectively absorb and shield electromagnetic waves and protect electronic devices and electronic circuits from interference and damage by electromagnetic radiation. This paper presents the research progress of intrinsically conductive polymer materials and conductive polymer-based composites for electromagnetic shielding as well as an introduction to lightweight polymer composites with multicomponent systems. These materials have excellent electromagnetic interference shielding properties and have the advantages of electromagnetic wave absorption and higher electromagnetic shielding effectiveness compared with conventional electromagnetic shielding materials, but these materials still have their own shortcomings. Finally, the paper also discusses the future opportunities and challenges of intrinsically conductive polymers and composites containing a conductive polymer matrix for electromagnetic shielding applications.
    Type of Medium: Online Resource
    ISSN: 1420-3049
    URL: Article
    DOI: 10.3390/molecules28227647
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2008644-1
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  • 10
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    Ensemble of Deep Convolutional Neural Networks for Automatic Pavement Crack Detection and Measurement
    MDPI AG ; 2020
    In:  Coatings Vol. 10, No. 2 ( 2020-02-08), p. 152-
    Details
    In: Coatings, MDPI AG, Vol. 10, No. 2 ( 2020-02-08), p. 152-
    Abstract: Automated pavement crack detection and measurement are important road issues. Agencies have to guarantee the improvement of road safety. Conventional crack detection and measurement algorithms can be extremely time-consuming and low efficiency. Therefore, recently, innovative algorithms have received increased attention from researchers. In this paper, we propose an ensemble of convolutional neural networks (without a pooling layer) based on probability fusion for automated pavement crack detection and measurement. Specifically, an ensemble of convolutional neural networks was employed to identify the structure of small cracks with raw images. Secondly, outputs of the individual convolutional neural network model for the ensemble were averaged to produce the final crack probability value of each pixel, which can obtain a predicted probability map. Finally, the predicted morphological features of the cracks were measured by using the skeleton extraction algorithm. To validate the proposed method, some experiments were performed on two public crack databases (CFD and AigleRN) and the results of the different state-of-the-art methods were compared. To evaluate the efficiency of crack detection methods, three parameters were considered: precision (Pr), recall (Re) and F1 score (F1). For the two public databases of pavement images, the proposed method obtained the highest values of the three evaluation parameters: for the CFD database, Pr = 0.9552, Re = 0.9521 and F1 = 0.9533 (which reach values up to 0.5175 higher than the values obtained on the same database with the other methods), for the AigleRN database, Pr = 0.9302, Re = 0.9166 and F1 = 0.9238 (which reach values up to 0.7313 higher than the values obtained on the same database with the other methods). The experimental results show that the proposed method outperforms the other methods. For crack measurement, the crack length and width can be measure based on different crack types (complex, common, thin, and intersecting cracks.). The results show that the proposed algorithm can be effectively applied for crack measurement.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    URL: Article
    DOI: 10.3390/coatings10020152
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2662314-6
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