Abstract
After the outbreak of COVID-19, unlike other countries in the world, China has always taken strict prevention and control measures, and even formed a trend of excessive epidemic prevention. ...Influenced by traditional culture, Chinese students’ willingness to study abroad has been greatly reduced, but long-term strict prevention will also lead to the public weariness of the epidemic. Therefore, our research group has formed a new “push–pull” theoretical analysis framework, carried out three rounds of the same volume investigation in the early (2020), middle (2021), and late (2022) stages of the epidemic, and 12,248 students from more than 270 universities in mainland China were investigated. Through tracking and investigating the changes in the willingness of Chinese students to study abroad at different stages of the epidemic, this study fills the gap in existing research that has not yet conducted a dynamic survey on the willingness of Chinese students to study abroad because of the epidemic. The results show that COVID-19 profoundly reversed the four influencing factors: study abroad pull, study abroad push, domestic pull, and domestic push. The epidemic and related factors have become new components of push–pull factors influencing Chinese students studying abroad. Under the government’s guidance of strict epidemic prevention measures, COVID-19 has dramatically reduced the willingness of Chinese students to study abroad, and effectively changed the preference for their studying destinations, which is related to national political ideology. However, under the excessive epidemic prevention, Chinese college students’ willingness to study abroad rebounded as the public’s acceptance of the epidemic increased in the latest period. This study has added new factors to the push–pull theory, providing inspiration for the advancement of the push–pull theory with the times. It also provides deeper thinking on the new pattern of talent mobility faced by different countries.
From the perspective of the complex system, university ranking is a complex system that involves multiagent actors, which evolve over time. Yet, current major university rankings fail to reflect the ...system dynamics of the university innovation system. In this paper, we apply the complex system model in the field of the university innovation system in the context of university ranking in the countries along the Belt and Road, which is a long-term overlooked field. We introduce a new method of university ranking based on the “winning and losing” relationship to measure the relative competitiveness between universities. This paper contributes to complex system research, the Belt and Road research, and the university ranking arena.
Flexible and implantable glucose biosensors are emerging technologies for continuous monitoring of blood-glucose of diabetes. Developing a flexible conductive substrates with high active surface area ...is critical for advancing the technology. Here, we successfully fabricate a flexible and highly sensitive nonenzymatic glucose by using DVD-laser scribed graphene (LSG) as a flexible conductively substrate. Copper nanoparticles (Cu-NPs) are electrodeposited as the catalyst. The LSG/Cu-NPs sensor demonstrates excellent catalytic activity toward glucose oxidation and exhibits a linear glucose detection range from 1 μM to 4.54 mM with high sensitivity (1.518 mA mM−1 cm−2) and low limit of detection (0.35 μM). Moreover, the LSG/Cu-NPs sensor shows excellent reproducibility and long-term stability. It is also highly selective toward glucose oxidation under the presence of various interfering species. Excellent flexing stability is also demonstrated by the LSG/Cu-NPs sensor, which is capable of maintaining 83.9% of its initial current after being bent against a 4-mm diameter rod for 180 times. The LSG/Cu-NPs sensor shows great potential for practical application as a nonenzymatic glucose biosensor. Meanwhile, the LSG conductive substrate provides a platform for the developing next-generation flexible and potentially implantable bioelectronics and biosensors.
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•A flexible and highly sensitive LSG/Cu-NPs glucose sensor is successfully fabricated.•Cu nanoparticle catalysts are electrodeposited on a laser-scribed-graphene substrate produced by a DVD drive.•The LSG/Cu-NPs sensor demonstrates a linear glucose detection range from 1 μM to 4.54 mM.•The LSG/Cu-NPs sensor exhibits high sensitivity (1.518 mA mM−1 cm−2) and low limit of detection (0.35 μM).•Excellent flexing stability and interfering resistance are demonstrated by the LSG/Cu-NPs sensor.
Abstract
The Guangdong‐Hong Kong‐Macao Greater Bay Area is becoming a new world economic centre, but research on the law of academic talent mobility in the Greater Bay Area is still scarce at ...present. This study builds an overall analysis framework, introduces the curriculum vitae analysis method, and systematically collects resumes of academics from universities in Guangdong, Hong Kong, and Macao. Through this, we try to find the stock, distribution, study origin and inflow of academic talents in the Greater Bay Area, the internal mobility of academic talents in the Greater Bay Area, and the global mobility network of academic talents in the Greater Bay Area. Academic mobility is a significant topic in higher education research, closely related to higher education's competitiveness and attractiveness. This research is of positive significance for clarifying the basic situation of academic talents in the Greater Bay Area, scientifically carrying out talent planning during the new stage of China's national economic and social development, and scientifically attracting talents based on the law of talent mobility.
Dental X-ray image segmentation is helpful for assisting clinicians to examine tooth conditions and identify dental diseases. Fast and lightweight segmentation algorithms without using cloud ...computing may be required to be implemented in X-ray imaging systems. This paper aims to investigate lightweight deep learning methods for dental X-ray image segmentation for the purpose of deployment on edge devices, such as dental X-ray imaging systems. A novel lightweight neural network scheme using knowledge distillation is proposed in this paper. The proposed lightweight method and a number of existing lightweight deep learning methods were trained on a panoramic dental X-ray image data set. These lightweight methods were evaluated and compared by using several accuracy metrics. The proposed lightweight method only requires 0.33 million parameters (
∼
7.5
megabytes) for the trained model, while it achieved the best performance in terms of IoU (0.804) and Dice (0.89) comparing to other lightweight methods. This work shows that the proposed method for dental X-ray image segmentation requires small memory storage, while it achieved comparative performance. The method could be deployed on edge devices and could potentially assist clinicians to alleviate their daily workflow and improve the quality of their analysis.
•We fabricate a humidity sensor with laser-scribed graphene electrode and graphite oxide sensing layer.•The fabrication process is done by a low power (5 mW) DVD drive.•The LSG-GO humidity sensor ...operates in the relative humidity (RH) range of 19 %–97.4 %.•The LSG based humidity sensor demonstrates high sensitivity (4770.14 pF/% RH).•Excellent sensing stability for more than 30 days has been demonstrated.
Monitoring the environmental humidity are of great significance to human comfort and product quality in many fields. However, high performance humidity sensors are difficult to be widely used because of their cost and complex preparation process. It is also highly desirable to develop a facile fabrication method that is capable of producing humidity sensors of customized size, shape, and geometry. Here, using a low power DVD drive, we successfully fabricate a highly sensitivity and low-cost humidity sensor, consisting of laser-scribed graphene (LSG) electrode and graphite oxide (GO) sensing layer. The LSG-GO humidity sensor operates in the relative humidity (RH) range of 19 %–97.4 %, demonstrating high sensitivity (4770.14 pF/% RH), quick response/recovery, and excellent sensing stability. In addition, the possible humidity sensing mechanism is discussed with the help of impedance spectroscopy. These results indicate that the LSG/GO sensor, enabled by the facile fabrication process with low power DVD drives, demonstrates promising potential with broad application prospects.
Laser reduction of graphene oxide (GO) produces graphene effectively. As a low-power laser source, commercial digital video disc (DVD) drives provide a versatile platform to produce reduced graphene ...films in designed 2D patterns. However, research on how GO characteristics affect its laser reduction efficiency in DVD drives is rarely conducted. Here, we investigate how heating the GO dispersion affects the photoreduction process of GO films in a LightScribe DVD drive. Without noticeably changing the oxygen content, such mild heat treatment significantly improves GO’s absorption in the visible region, resulting in significant enhancement on GO’s laser reduction efficiency. We demonstrate that the laser reduction efficiency increases with the increasing treatment time. The enhanced reduction level greatly improves the performance of laser-scribed graphene electrodes in applications such as glucose sensors (with an optimal linear response range up to 2550 μM) and supercapacitors (with an optimal areal capacity of 1.37 mF cm–2 at the scan rate of 50 mV s–1). This proposed approach provides general insights into the production of laser-reduced graphene with low-power laser sources, for advanced device applications such as wearable electronics and flexible microelectronics.
In the context of global innovation systems, it has become a universal law that the resource elements of scientific and technological innovation, such as talents, flow along the track of high ...efficiency to the regions that can produce high benefits. As faculty in research universities are important resources of scientific and technological innovation, developing countries such as China have sought to accelerate the transnational mobility of faculty by leveraging income. This study endeavors to gain a better understanding of the motivations for and the outcomes of faculty mobility at Chinese research universities and to determine whether attaining higher income levels through academic mobility can be considered a lever for facilitating change and improving the status of the academic profession in China. Using survey data from 445 faculty members at 11 major research universities in China, this study found a significant relationship between mobility frequency and indirect income. The findings also revealed, however that employees’ different attitudes toward income during the process of mobility are a key variable in confirming academic professional boundaries. The findings suggest that more successful mechanisms to attract or retain talented scholars should be developed and that these mechanisms should not focus exclusively on income.
Flexible pressure sensors possess vast potential for various applications such as new energy batteries, aerospace engines, and rescue robots owing to their exceptional flexibility and adaptability. ...However, the existing sensors face significant challenges in maintaining long-term reliability and environmental resilience when operating in harsh environments with variable temperatures and high pressures (∼MPa), mainly due to possible mechanical mismatch and structural instability. Here, we propose a composite scheme for a flexible piezoresistive pressure sensor to improve its robustness by utilizing material design of near-zero temperature coefficient of resistance (TCR), radial gradient pressure-dividing microstructure, and flexible interface bonding process. The sensing layer comprising multiwalled carbon nanotubes (MWCNTs), graphite (GP), and thermoplastic polyurethane (TPU) was optimized to achieve a near-zero temperature coefficient of resistance over a temperature range of 25–70 °C, while the radial gradient microstructure layout based on pressure division increases the range of pressure up to 2 MPa. Furthermore, a flexible interface bonding process introduces a self-soluble transition layer by direct-writing TPU bonding solution at the bonding interface, which enables the sensor to achieve signal fluctuations as low as 0.6% and a high interface strength of up to 1200 kPa. Moreover, it has been further validated for its capability of monitoring the physiological signals of athletes as well as the long-term reliable environmental resilience of the expansion pressure of the power cell. This work demonstrates that the proposed scheme sheds new light on the design of robust pressure sensors for harsh environments.
Abstract Hydrogels are extensively explored as biomaterials for tissue scaffolds, and their controlled fabrication has been the subject of wide investigation. However, the tedious mechanical property ...adjusting process through formula control hindered their application for diverse tissue scaffolds. To overcome this limitation, we proposed a two-step process to realize simple adjustment of mechanical modulus over a broad range, by combining digital light processing (DLP) and post-processing steps. UV-curable hydrogels (polyacrylamide-alginate) are 3D printed via DLP, with the ability to create complex 3D patterns. Subsequent post-processing with Fe 3+ ions bath induces secondary crosslinking of hydrogel scaffolds, tuning the modulus as required through soaking in solutions with different Fe 3+ concentrations. This innovative two-step process offers high-precision (10 μm) and broad modulus adjusting capability (15.8–345 kPa), covering a broad range of tissues in the human body. As a practical demonstration, hydrogel scaffolds with tissue-mimicking patterns were printed for cultivating cardiac tissue and vascular scaffolds, which can effectively support tissue growth and induce tissue morphologies.
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