ARTICLE | doi:10.20944/preprints202302.0266.v1
Subject: Social Sciences, Education Keywords: entrepreneurship education; entrepreneurial self-efficacy; entrepreneurial intention; higher vocational students; China
Online: 16 February 2023 (03:55:20 CET)
To reveal the influence of variables such as entrepreneurial learning, entrepreneurial inspiration, and incubation resources on students' entrepreneurial intentions in vocational colleges, this study took vocational colleges in Zhejiang Province, a province with a strong entrepreneurial climate in China, as an example. The study used a questionnaire to obtain data, and 614 valid questionnaires were collected from seven vocational colleges. The study divided entrepreneurship education into three dimensions: entrepreneurial learning, entrepreneurial inspiration, and incubation resources, and used structural equation modeling to investigate the influence of entrepreneurship education on entrepreneurial intentions while introducing entrepreneurial efficacy as a mediating variable to examine the influence mechanism of entrepreneurship education on entrepreneurial intentions of higher education students. The results showed that entrepreneurial learning, entrepreneurial inspiration, incubation resources, and entrepreneurial efficacy were all significantly and positively correlated with entrepreneurial intentions and that entrepreneurial efficacy mediated between the two dimensions of entrepreneurship education (entrepreneurial learning and entrepreneurial inspiration) and entrepreneurial intentions. Therefore, to enhance the effectiveness of entrepreneurship education in vocational institutions, we should stimulate students' sense of entrepreneurial efficacy, strengthen their entrepreneurial learning and inspire them to start their businesses. In turn, university incubation resources can be developed and utilized to enhance students' entrepreneurial confidence and intentions.
ARTICLE | doi:10.20944/preprints201808.0248.v1
Subject: Engineering, Energy And Fuel Technology Keywords: photovoltaic panel; explicit model; spectrum splitting; I-V characteristic prediction; shape parameter
Online: 23 August 2018 (11:03:53 CEST)
Looking at different operating climatic conditions, the electrical behavior predicting photovoltaic modules gets very important. For the estimation of output power from photovoltaic (PV) plants this is a very essential and basic aspect. In this paper, the relationship between the I-V curve and the irradiation spectrum is discussed by combining the single diode model. An explicit elementary analytical model with two defined shape parameters is discussed and improved with three approximations and second order Taylor expansion. Then, the explicit elementary analytical model is investigated under varying conditions leveraging the four parameters Iph, I0, Rs and Rsh from the single diode model. The relationship between the physical parameters and the condition parameters are discussed and applied to extract the shape parameters at different scenarios. Considering the aging effect, the process of calculation to predict the I-V curve under different splitting spectra is simplified as follow: (1) two shape parameters are gotten from the I-V data at measurement reference conditions (MRC); (2) the short circuit current, open circuit voltage and shape parameters under any splitting spectrum can be calculated based on the relationship provided in article; (3) the performance of PV panel can be predicted with parameters. The validation of this model was experimentally proven leveraging monocrystalline silicon photovoltaic module with different splitting films. Results showed that the model accurately predicts the I-V characteristics for the examined PV modules at different irradiance spectra and cell temperatures. Moreover, the presented model performs superior compared to other investigated models when looking at accuracy and simplicity.
REVIEW | doi:10.20944/preprints201809.0057.v1
Subject: Physical Sciences, Condensed Matter Physics Keywords: metal-insulator transitions; electronic transport in interface structures; quantum hall effects
Online: 4 September 2018 (06:03:44 CEST)
The apparent metal-insulator transition (MIT) in two-dimension (2D) was discovered by Kravchenko et al.  more than two decades ago in strongly interacting 2D electrons residing in a Si-metal-oxide-semiconductor field-effect transistor (Si-MOSFET). Its origin remains unresolved. Recently, low magnetic field reentrant insulating phases (RIPs), which dwell between the zero-field (B=0) metallic state and the integer quantum Hall (QH) states where the Landau-level filling factor υ > 1, have been observed in strongly correlated 2D GaAs hole systems with large interaction parameter rs (~20-40) and high purity. A new complex phase diagram was proposed, which includes zero field MIT, low magnetic field RIPs, integer QH states, fractional QH states, high field RIPs and insulating phases (HFIPs) with υ < 1 in which the insulating phases are explained by the formation of Wigner crystal. Furthermore, evidences of new intermediate phases were reported. All contribute to the further understandings of the puzzle. This review article serves the purpose of summarizing those recent experimental findings and theoretical endeavors, to foster future research efforts.
ARTICLE | doi:10.20944/preprints202204.0240.v1
Subject: Engineering, Civil Engineering Keywords: Deep Learning; Aerial photo; Typhoon Faxai; roof damage; detection; classification
Online: 26 April 2022 (10:58:36 CEST)
Following the occurrence of a typhoon, quick damage assessment related to residents can facilitate quick dispatch of house repair and disaster insurance works. Employing a deep learning method, this study used aerial photos of the Chiba prefecture obtained following the Typhoon Faxai in 2019 to automatically detect and evaluate the roof damage. This study comprised three parts: training deep learning model, detecting the roof damage using trained model, and classifying the level of roof damage. The detection object comprised roof outline, blue tarps, and roof completely destroyed. The roofs were divided into three categories: roof without damage, roof with blue tarps and roof completely destroyed. the F value obtained using the proposed method was higher than those obtained using other methods. In addition, it can be further divided into 5 levels from level 0 to 4. Finally, the spatial distribution of the roof damage was analyzed using ArcGIS tools. The proposed method is expected to provide certain reference for the real-time detection of the roof damage after the occurrence of a typhoon.
ARTICLE | doi:10.20944/preprints202001.0081.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: Berberine; Lipophilic substituent; Anti-cancer activity; Photocytotoxicity; Reactive oxygen species
Online: 9 January 2020 (11:30:40 CET)
The objective of this study was to synthesize 9-/13-position substituted berberine derivatives and evaluated their cytotoxic and photocytotoxic effects against three human cancer cell lines. Among all the synthesized compounds, 9-O-dodecyl- (5e), 13-dodecyl- (6e) and 13-O-dodecyl-berberine (7e) exhibited stronger growth inhibition against three human cancer cell lines, (HepG2, HT-29 and BFTC905), in compare with structurally related berberine (1). These three compounds also showed the photocytotoxicity in human cancer cells in a concentration-dependent and light dose-dependent manner. Through flow cytometry analysis, we found out a lipophilic group at 9-/13-position of berberine may have facilitated its penetration into test cell and hence enhanced its photocytotoxicity on human liver cancer cell HepG2. Further, in cell cycle analysis, 5e, 6e and 7e induced HepG2 cells to arrest at S phase and caused apoptosis upon irradiation. In addition, photodynamic treatment of berberine (1) and its derivatives 5e, 6e and 7e again showed a significant photocytotoxic effects on HepG2 cells, induced remarkable cell apoptosis, greatly increased intracellular ROS level and the loss of mitochondrial membrane potential. These results over and again confirmed that berberine derivatives 5e, 6e and 7e greatly enhanced photocytotoxicity. Taking together, the test data led us to conclude that berberine derivatives with a dodecyl group at 9-/13-position could be great candidates for the anti-liver cancer medicines developments.