Showing papers by "Nanjing University published in 2022"

A long short-term memory-based model for greenhouse climate prediction

Abstract: Greenhouses can grow many off‐season vegetables and fruits, which improves people's quality of life. Greenhouses can also help crops resist natural disasters and ensure the stable growth of crops. However, it is highly challenging to carefully control the greenhouse climate. Therefore, the proposal of a greenhouse climate prediction model provides a way to solve this challenge. We focus on the six climatic factors that affect crops growth, including temperature, humidity, illumination, carbon dioxide concentration, soil temperature and soil humidity, and propose a GCP_lstm model for greenhouse climate prediction. The climate change in greenhouse is nonlinear, so we use long short‐term memory (LSTM) model to capture the dependence between historical climate data. Moreover, the short‐term climate has a greater impact on the future trend of greenhouse climate change. Therefore, we added a 5‐min time sliding window through the analysis experiment. In addition, sensors sometimes collect wrong climate data. Based on the existence of abnormal data, our model still has good robustness. We experienced our method on the data sets of three vegetables: tomato, cucumber and pepper. The comparison shows that our method is better than other comparison models.

Biomedical polymers: synthesis, properties, and applications

Abstract: Biomedical polymers have been extensively developed for promising applications in a lot of biomedical fields, such as therapeutic medicine delivery, disease detection and diagnosis, biosensing, regenerative medicine, and disease treatment. In this review, we summarize the most recent advances in the synthesis and application of biomedical polymers, and discuss the comprehensive understanding of their property-function relationship for corresponding biomedical applications. In particular, a few burgeoning bioactive polymers, such as peptide/biomembrane/microorganism/cell-based biomedical polymers, are also introduced and highlighted as the emerging biomaterials for cancer precision therapy. Furthermore, the foreseeable challenges and outlook of the development of more efficient, healthier and safer biomedical polymers are discussed. We wish this systemic and comprehensive review on highlighting frontier progress of biomedical polymers could inspire and promote new breakthrough in fundamental research and clinical translation.

1.95-kV Beveled-Mesa NiO/β-Ga 2 O 3 Heterojunction Diode With 98.5% Conversion Efficiency and Over Million-Times Overvoltage Ruggedness

Abstract: The technical progress of Ga2O3 power diodes is now stuck at a critical point where a lack of performance evaluation and reliability validation at the system-level applications seriously limits their further development and even future commercialization. In this letter, by implementing beveled-mesa NiO/Ga2O3 p–n heterojunction diodes (HJDs) into a 500-W power factor correction (PFC) system circuit, high conversion efficiency of 98.5% with 100-min stable operating capability has been demonstrated. In particular, rugged reliability is validated after over 1 million times dynamic breakdown with a 1.2-kV peak overvoltage. Meanwhile, superior device performance is achieved, including a static breakdown voltage (BV) of 1.95 kV, a dynamic BV of 2.23 kV, a forward current of 20 A (2 kA/cm2 current density), and a differential specific on -resistance of 1.9 mΩ·cm2. These results indicate that Ga2O3 power HJDs are developing rapidly with their own advantages, presenting the enormous potential in high-efficiency, high-power, and high-reliability applications.

MoS 2 -Templated Porous Hollow MoO 3 Microspheres for Highly Selective Ammonia Sensing via a Lewis Acid-Base Interaction

Abstract: The development of a high-performance sensing material for the detection of ammonia gas is of significant importance due to its wide industrial presence and potential hazard risks In this article, we report the synthesis of porous and hollow MoO3 (p-h-MoO3) microspheres via the oxidation of MoS2 microsphere templates, which are obtained via self-assembly of MoS2 nanosheets under hydrothermal conditions The composition and morphology of the p-h-MoO3 microspheres are systematically characterized via microscopic and spectroscopic techniques, and our sensing tests reveals that p-h-MoO3 possesses ultrahigh responsiveness to ammonia gas, which can be further optimized via the selection of a suitable oxidation temperature and time Additionally, the p-h-MoO3 shows minimal responses to other gaseous molecules, thereby demonstrating significant selectivity toward ammonia The sensing mechanism of p-h-MoO3 toward ammonia is further investigated to identify the origin of its ultrahigh sensitivity and selectivity via X-ray photoelectron spectroscopy and diffuse reflectance Fourier transform infrared spectroscopy

Highly active atomically dispersed platinum-based electrocatalyst for hydrogen evolution reaction achieved by defect anchoring strategy

Abstract: Single-atom catalysts (SACs) can achieve ultimate atomic utilization of precious metals to improve water splitting’s economy. However, active sites in SACs are usually insufficient. Therefore, we propose the use of porous Co1NC which is rich in defects as support to prepare Pt1/Co1NC by mild electrochemical reduction at room temperature. Pt1/Co1NC showed record-high hydrogen evolution reaction (HER) activity, with an overpotential of only 4.15 mV at a current density of 10 mA cm−2. Its mass activity reached 32.4 A mg−1Pt at an overpotential of 20 mV, which is 54 times that of Pt/C. The turnover frequency was up to 32.86 s−1 at 20 mV, with excellent stability in long-term service. Our strategy suggests that nitrogen/carbon defects are vital for anchoring&forming monodispersed Pt active sites while preventing agglomeration. These sites possess low energy barriers, as verified by theoretical simulations. Therefore, our method presents a technical breakthrough for reducing cost of hydrogen energy.