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  • MDPI AG  (27)
  • Yang, Zihan  (27)
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  • MDPI AG  (27)
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  • 1
    In: Processes, MDPI AG, Vol. 9, No. 12 ( 2021-12-20), p. 2281-
    Abstract: With the gradual deepening of the development of high-quality urban transformation, the “Danwei Compound” urban space production method constitutes the basis of Chinese current urban spatial transformation. The transformation plan of the original danwei compound “stock” to promote the healthy development of urban society has become the focus of research. First, with the help of Lefebvre’s space production theory, combined with the spatial transformation characteristics of its own structural form experienced by the Chinese urban danwei compound, the space production is divided into three stages, namely, the diversity-orderly type average space of the danwei compound system period, dispersed type abstract space of the commercial enclosed community period, and the integrated differential space of a livable community undergoing regeneration and transformation. At each stage, the government, market, and residents have different influences on time-space production. Secondly, using Hefei’s typical danwei compound as the research carrier, according to the space ternary dialectics, a multi-level analysis of “representations of space-representational space-spatial practice” is carried out on the production mechanism, and the logic of different types of spaces in different periods are described. Among them, the representations of space of the change of the danwei compound are the interrelationship of multiple governance subjects in different periods, such as changes in the implementation degree of governance strategies, the degree of residents’ community governance participation, residents’ satisfaction with community governance, etc. The representational space is the residents’ community perception and interpersonal relationship at different transition stages, Interpersonal trust, and other social relations’ changes. Spatial practice is manifested in changes in the support of public service facilities, public space, per capita living area, building quality, architectural style, and illegal building area. Finally, the three-dimensional space dialectical coupling coordination degree model is used to analyze and compare the representations of space of typical settlements in the three stages and the coupling characteristics of the representational space and the practice of space. On this basis, we provide innovative ideas and put forward relevant measures and suggestions for the regeneration, transformation, and development of livable areas.
    Type of Medium: Online Resource
    ISSN: 2227-9717
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2720994-5
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  • 2
    Online Resource
    Online Resource
    MDPI AG ; 2022
    In:  Coatings Vol. 13, No. 1 ( 2022-12-28), p. 52-
    In: Coatings, MDPI AG, Vol. 13, No. 1 ( 2022-12-28), p. 52-
    Abstract: High-entropy alloys (HEAs) have received increasing attention because of their excellent properties. To improve the surface hardness and wear resistance of pure Cu, a Cu35Ni25Co25Cr15 HEA coating was, for the first time, deposited on a pure Cu substrate by plasma transfer arc (PTA) welding. The welding current varied from 130 to 160 A. The microstructures and mechanical properties of the coating were investigated. The Cu35Ni25Co25Cr15 HEA coating comprised face-cubic-centered A1 (Cu-rich) and γ′ (NiCoCr-rich) phases. The coating had an apparent structural gradient with coarse grains at the interface with the Cu substrate. The bottom, middle, and top zones of the coating exhibited a fine smooth cellular structure, fine-needle structure, and long dendrites, respectively. As the welding current was increased, the dilution ratio of the coating and interfacial bonding strength gradually increased, whereas the hardness of the coating increased and then decreased. Under a welding current of 150 A, no gaps or pores appeared in the interface, and the coating exhibited good metallurgical bonding with the Cu substrate. The wear mechanisms of the Cu35Ni25Co25Cr15 HEA coating at different temperatures were also determined. Compared with pure Cu, the Cu35Ni25Co25Cr15 HEA coating exhibited excellent wear resistance, especially at high temperatures. This study paves a new way for coating on pure Cu and enhances the wear resistance of Cu components.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2662314-6
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  • 3
    In: Foods, MDPI AG, Vol. 11, No. 17 ( 2022-08-31), p. 2646-
    Abstract: The quality of Tibetan matsutake drops during cold chain transportation. To extend the shelf life and improve the market value, this study analyzed the matsutake logistics process, and optimized the dynamic monitoring and quality management systems for post-harvest matsutake with different preservation packaging in the cold chain. This system monitored the micro-environmental parameters of the cold chain in real time, and it identified the best preservation method by analyzing the quality change characteristics of the matsutake with different preservation packaging. It was concluded that the matsutake were best preserved under the conditions of modified atmosphere packaging. The data analysis on the collected data verified the performance of the system. Relevant personnel were invited to participate in the system performance analysis and offer optimization suggestions to improve the applicability of the established monitoring system. The optimized model could provide a more effective theoretical reference for the dynamic monitoring and quality management of the system.
    Type of Medium: Online Resource
    ISSN: 2304-8158
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2704223-6
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  • 4
    In: Applied Sciences, MDPI AG, Vol. 11, No. 19 ( 2021-10-04), p. 9230-
    Abstract: Wheat take-all, caused by two variants of the fungus Gaeumannomyces gramnis (Sacc.) Arx & D. Olivier, was common in spring wheat areas in northwest and north China and occurred in winter wheat areas in north China. The yield of common disease areas was reduced by more than 20% and the yield of severe cases was reduced by more than 50%. Large-scale rapid and accurate estimation of the incidence of wheat take-all plays an important role in guiding field control and agricultural yield estimation. In this study, a portable ground spectrometer was used to collect the spectral reflectance in the 350–1050 nm band range of wheat canopy after take-all infection in the wheat grain filling stage and combined with the ground disease survey data.Then a winter wheat take-all disease index estimation model was proposed based on the spectral band division interval and selected band combination. According to the normalized difference spectral index (NDSI) and the determinative coefficient of the disease index formed by any two band combinations, the spectral index band combinations corresponding to the spectral index with high correlation in each region were screened by dividing spectral intervals. Partial least-squares regression was used to establish a binary and ternary disease index calibration model. The results showed that the model based on spectral indices of ternary variables had the highest coefficient of determination. Finally, the optimal regression model of wheat take-all disease condition index composed of NDSI(R590,R598), NDSI(R534,R742) and NDSI(R810,R834) was established: Y = 134.577 − 70.301 NDSI(R590,R598) − 223.533 NDSI(R534,R742) + 51.584 NDSI(R810,R834) (R2 = 0.743, RMSEP = 0.094, df = 15), which was the most suitable model for winter wheat take-all estimation. The construction of this model can provide new method and technical support for future evaluation and monitoring of wheat take-all disease on the field.
    Type of Medium: Online Resource
    ISSN: 2076-3417
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2704225-X
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  • 5
    In: Sustainability, MDPI AG, Vol. 12, No. 1 ( 2019-12-20), p. 64-
    Abstract: Livelihood diversification is beneficial to mitigate economic and environmental risks and to improve livelihood sustainability and regional sustainable development. Unsettled herder households (UHH), settled herder households (SHH) and farmer households (FH) are different household types in far northwestern China whose livelihood diversification has not been fully explored. By applying a framework of livelihood diversification, this paper presents a comparative analysis of the characteristics and determinants of the diversification of the three household types. The results show that livelihood assets have been unequally distributed, with FH possessing the least assets; however, FH are better than UHH and SHH in the diversification of livelihood activities. Agriculture remains the most important livelihood source. The high-income groups of the three household types have a higher number of livelihood activities but do not necessarily hold an advantage in equality of livelihood activities. Labor capacity and income are positively related to the number of livelihood activities for the three household types. Livestock size is negatively associated with the number of activities of herders. Moreover, age and subsidy have negative impacts on the number of activities for UHH. Based on the findings, we provide policy suggestions on livelihood enhancement and sustainable and effective development of pastoral regions.
    Type of Medium: Online Resource
    ISSN: 2071-1050
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2518383-7
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  • 6
    In: Applied Sciences, MDPI AG, Vol. 12, No. 1 ( 2021-12-31), p. 407-
    Abstract: Truss size and topology optimization problems have recently been solved mainly by many different metaheuristic methods, and these methods usually require a large number of structural analyses due to their mechanism of population evolution. A branched multipoint approximation technique has been introduced to decrease the number of structural analyses by establishing approximate functions instead of the structural analyses in Genetic Algorithm (GA) when GA addresses continuous size variables and discrete topology variables. For large-scale trusses with a large number of design variables, an enormous change in topology variables in the GA causes a loss of approximation accuracy and then makes optimization convergence difficult. In this paper, a technique named the label–clip–splice method is proposed to improve the above hybrid method in regard to the above problem. It reduces the current search domain of GA gradually by clipping and splicing the labeled variables from chromosomes and optimizes the mixed-variables model efficiently with an approximation technique for large-scale trusses. Structural analysis of the proposed method is extremely reduced compared with these single metaheuristic methods. Numerical examples are presented to verify the efficacy and advantages of the proposed technique.
    Type of Medium: Online Resource
    ISSN: 2076-3417
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2704225-X
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  • 7
    In: Biomedicines, MDPI AG, Vol. 11, No. 3 ( 2023-03-06), p. 802-
    Abstract: Early detection and diagnosis of oral cancer are critical for a better prognosis, but accurate and automatic identification is difficult using the available technologies. Optical coherence tomography (OCT) can be used as diagnostic aid due to the advantages of high resolution and non-invasion. We aim to evaluate deep-learning-based algorithms for OCT images to assist clinicians in oral cancer screening and diagnosis. An OCT data set was first established, including normal mucosa, precancerous lesion, and oral squamous cell carcinoma. Then, three kinds of convolutional neural networks (CNNs) were trained and evaluated by using four metrics (accuracy, precision, sensitivity, and specificity). Moreover, the CNN-based methods were compared against machine learning approaches through the same dataset. The results show the performance of CNNs, with a classification accuracy of up to 96.76%, is better than the machine-learning-based method with an accuracy of 92.52%. Moreover, visualization of lesions in OCT images was performed and the rationality and interpretability of the model for distinguishing different oral tissues were evaluated. It is proved that the automatic identification algorithm of OCT images based on deep learning has the potential to provide decision support for the effective screening and diagnosis of oral cancer.
    Type of Medium: Online Resource
    ISSN: 2227-9059
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2720867-9
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  • 8
    Online Resource
    Online Resource
    MDPI AG ; 2023
    In:  Photonics Vol. 10, No. 2 ( 2023-02-05), p. 169-
    In: Photonics, MDPI AG, Vol. 10, No. 2 ( 2023-02-05), p. 169-
    Abstract: In this paper, a learning-based fiber specklegram sensor for bending recognition is proposed and demonstrated. Specifically, since the curvature-induced variations of mode interference in optical fibers can be characterized by speckle patterns, Resnet18, a classification model based on convolutional neural network architecture with excellent performance, is used to identify the bending state and disturbed position simultaneously according to the speckle patterns collected from the distal end of the multimode fiber. The feasibility of the proposed scheme is verified by rigorous experiments, and the test results indicate that the proposed sensing system is effective and robust. The accuracy of the trained model is 99.13%, and the prediction speed can reach 4.75 ms per frame. The scheme proposed in this work has the advantages of low cost, easy implementation, and a simple measurement system and is expected to find applications in distributed sensing and bending identification in complex environments.
    Type of Medium: Online Resource
    ISSN: 2304-6732
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2770002-1
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  • 9
    Online Resource
    Online Resource
    MDPI AG ; 2023
    In:  Micromachines Vol. 14, No. 11 ( 2023-11-20), p. 2127-
    In: Micromachines, MDPI AG, Vol. 14, No. 11 ( 2023-11-20), p. 2127-
    Abstract: A continuous transverse stub (CTS) array antenna with broad bandwidth and high-power handling capacity is proposed in this paper. The technologies of multi-step impedance matching and T-shaped electromagnetic band-gap (EBG) loading are utilized, which improved the antenna operating frequency bandwidth. An H-plane lens horn is used to feed the CTS array. As a result, a good bandwidth capability of more than 32% is achieved, with a gain variation less than 3.0 dB. The measured sidelobe level (SLL) is below −18 dB in the entire frequency range. Moreover, the power handling capacity of the antenna is more than 80 MW and can reach the GW level after arraying, which indicates that this antenna has application potential in the high-power microwave (HPM) field.
    Type of Medium: Online Resource
    ISSN: 2072-666X
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2620864-7
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  • 10
    In: Sustainability, MDPI AG, Vol. 14, No. 22 ( 2022-11-09), p. 14772-
    Abstract: A comprehensive evaluation is important for the sustainable development of entrepreneurship education in colleges and universities. Specifically, evaluating entrepreneurship education in colleges and universities from the perspective of teachers, as stakeholders of entrepreneurship education in colleges and universities, can provide a basis for decision making to improve the quality of entrepreneurship education. Using the improved entropy–TOPSIS method, this study selects 35 indicators from five aspects, namely, curriculum systems, organizational leadership, faculty construction, teaching management, and an institutional guarantee, to establish a sustainable and comprehensive evaluation framework for entrepreneurship education in colleges and universities. Survey data from a questionnaire of college teachers in 11 provinces (cities) in China’s Yangtze River economic zone are used. The objective is to propose a framework that enables a comprehensive evaluation of the sustainability of entrepreneurship education and to develop a new evaluation method that highlights the challenges in evaluating the sustainability of entrepreneurship education, including the selection and effective measurement of the evaluation criteria. The study provides a scientific basis and support for decision making on the optimal reform of entrepreneurship education, faculty allocation, and education methods in Chinese universities and contributes to the realization of the goal of sustainable development of entrepreneurship education in universities.
    Type of Medium: Online Resource
    ISSN: 2071-1050
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2518383-7
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