Nanjing University

About: Nanjing University is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Catalysis & Adsorption. The organization has 85961 authors who have published 105504 publications receiving 2289036 citations. The organization is also known as: NJU & Nanking University.

Cadmium sulfide-based nanomaterials for photocatalytic hydrogen production

Abstract: Solar hydrogen generation via photocatalytic water splitting represents an attractive strategy to address the global energy crisis and environmental pollution issues. CdS-based photocatalysts, including nanosized CdS powder, CdS-based solid solutions and CdS quantum dots, have attracted significant attention for photocatalytic H2 production due to their unique advantages, including strong visible light absorption capacity, suitable band edge levels and excellent electronic charge transfer. This review focuses on recent advances in material design and technological aspects of CdS-based photocatalysts for applications in photocatalytic H2 production. A brief overview of basic concepts and principles of photocatalytic water splitting was given in the Introduction section, followed by the basic properties of CdS. Then, the utilization of three main types of CdS-based semiconductor photocatalysts for solar H2 generation is introduced, and those important factors which can determine the photocatalytic performance were also discussed in detail. Special consideration has been given to the effect of morphology, interfacial junctions, exposing facet and cocatalysts on the photocatalytic performance of CdS-based photocatalysts. Finally, a roadmap of possible future directions to further explore the research field of CdS-based photocatalysts for solar H2 generation is also discussed.

H6 Transformerless Full-Bridge PV Grid-Tied Inverters

Abstract: Transformerless inverters are widely used in grid-tied photovoltaic (PV) generation systems, due to the benefits of achieving high efficiency and low cost. Various transformerless inverter topologies have been proposed to meet the safety requirement of leakage currents, such as specified in the VDE-4105 standard. In this paper, a family of H6 transformerless inverter topologies with low leakage currents is proposed, and the intrinsic relationship between H5 topology, highly efficient and reliable inverter concept (HERIC) topology, and the proposed H6 topology has been discussed as well. One of the proposed H6 inverter topologies is taken as an example for detail analysis with operation modes and modulation strategy. The power losses and power device costs are compared among the H5, the HERIC, and the proposed H6 topologies. A universal prototype is built for these three topologies mentioned for evaluating their performances in terms of power efficiency and leakage currents characteristics. Experimental results show that the proposed H6 topology and the HERIC achieve similar performance in leakage currents, which is slightly worse than that of the H5 topology, but it features higher efficiency than that of H5 topology.

Dynamics of Controlled Mechanical Systems with Delayed Feedback

Abstract: 1 Modeling of Delayed Dynamic Systems.- 2 Fundamentals of Delay Differential Equations.- 3 Stability Analysis of Linear Delay Systems.- 4 Robust Stability of Linear Delay Systems.- 5 Effects of a Short Time Delay on System Dynamics.- 6 Dimensional Reduction of Nonlinear Delay Systems.- 7 Periodic Motions of Nonlinear Delay Systems.- 8 Delayed Control of Dynamic Systems.- References.

Trends in temperature extremes during 1951–1999 in China

Abstract: [1] Based on the daily surface air temperature data from about 200 stations during 1951-1999 in China, changes in the frequency of some extreme temperature events were studied with a focus on trends. For China as a whole, the number of hot days (Tmax over 35°C) displays a slightly decreasing trend, while the number of frost days (Tmin below 0°C) exhibits a significant decreasing trend. Meanwhile, increasing trends were detected in the frequencies of warm days and warm nights. In addition, decreasing trends was found in the frequencies of cool days and even stronger decreasing trend was found in frequencies of cool nights in China.