Nanjing University of Information Science and Technology

About: Nanjing University of Information Science and Technology is a education organization based out in Nanjing, China. It is known for research contribution in the topics: Precipitation & Aerosol. The organization has 14129 authors who have published 17985 publications receiving 267578 citations. The organization is also known as: Nan Xin Da.

Unraveling the cause-effect relation between time series.

Abstract: Given two time series, can one faithfully tell, in a rigorous and quantitative way, the cause and effect between them? Based on a recently rigorized physical notion, namely, information flow, we solve an inverse problem and give this important and challenging question, which is of interest in a wide variety of disciplines, a positive answer. Here causality is measured by the time rate of information flowing from one series to the other. The resulting formula is tight in form, involving only commonly used statistics, namely, sample covariances; an immediate corollary is that causation implies correlation, but correlation does not imply causation. It has been validated with touchstone linear and nonlinear series, purportedly generated with one-way causality that evades the traditional approaches. It has also been applied successfully to the investigation of real-world problems; an example presented here is the cause-and-effect relation between the two climate modes, El Nino and the Indian Ocean Dipole (IOD), which have been linked to hazards in far-flung regions of the globe. In general, the two modes are mutually causal, but the causality is asymmetric: El Nino tends to stabilize IOD, while IOD functions to make El Nino more uncertain. To El Nino, the information flowing from IOD manifests itself as a propagation of uncertainty from the Indian Ocean.

A review on hydrothermal carbonization of biomass and plastic wastes to energy products

Abstract: Hydrothermal carbonization (HTC) as a promising thermochemical process can convert organic solid wastes (e.g., biomass, plastics) into valuable products (i.e., hydrochar) at relatively low temperatures (180–250 °C) and saturated pressures (2–10 MPa). Hydrothermal conversion generally occurs via dehydration, polymerization and finally carbonization reactions. The carbon materials derived from hydrochar have high potential in various applications such as solid fuel, supercapacitor, fuel cell, and sorbent. Although the energy densification of hydrochar was increased at higher temperatures, most of the benefit was achieved at modest temperatures. Chemical structures of hydrochars include crosslinks of aromatic polymer, surface porosity, organic functional groups and ultimate components. All of these characteristics can be changed significantly by HTC, influencing the reactivity and fuel properties of hydrochars. The reaction pathways including negative and positive effects during (co)-HTC of biomass and plastic wastes are thoroughly concluded. In particular, the co-HTC of chlorinated plastic (e.g., PVC) and biomass can enhance the dechlorination and inorganics removal from hydrochar.

Fast Motion Estimation Based on Content Property for Low-Complexity H.265/HEVC Encoder

Abstract: The high definition (HD) and ultra HD videos can be widely applied in broadcasting applications. However, with the increased resolution of video, the volume of the raw HD visual information data increases significantly, which becomes a challenge for storage, processing, and transmitting the HD visual data. The state-of-the-art video compression standard-H.265/High Efficiency Video Coding (HEVC) compresses the raw HD visual data efficiently, while the high compression rate comes at the cost of heavy computation load. Hence, reducing the encoding complexity becomes vital for the H.265/HEVC encoder to be used in broadcasting applications. In this paper, based on the best motion vector selection correlation among the different size prediction modes, we propose a fast motion estimation (ME) method to reduce the encoding complexity of the H.265/HEVC encoder. First, according to the prediction unit (PU) partition type, all PUs are classified into two classes, parent PU and children PUs, respectively. Then, based on the best motion vector selection correlation between the parent PU and children PUs, the block matching search process of the children PUs is adaptively skipped if their parent PU chooses the initial search point as its final optimal motion vector in the ME process. Experimental results show that the proposed method achieves an average of 20% ME time saving as compared with the original HM-TZSearch. Meanwhile, the rate distortion performance degradation is negligible.

Carbothermal synthesis of metal-functionalized nanostructures for energy and environmental applications

Abstract: Carbothermal reduction could be employed as a facile technology for the synthesis of various novel materials, especially transition-metal-functionalized nanostructures. In particular, energy materials, such as ZnO, MnO2, and LiFePO4, combined with different carbon nanostructures have been widely synthesized via carbothermal reduction, which could be well established industrially due to its low-cost starting materials. In addition, a variety of carbon sources can be employed as comparatively low-cost carbon precursors for the synthesis of carbonaceous functional materials, such as porous carbon-coated magnetic nanoparticles (e.g., Co3O4@C, Fe3O4@C, and FeC3–C). These functional materials have great potential for use in energy and environmental applications. Carbothermal reduction methods possess some incomparable advantages, such as convenience, relatively low cost, and good repeatability, for commercial applications. However, they normally require a relatively high temperature for sustaining carbothermic reaction. Consequently, novel structures can also be derived from renewable, abundant carbon precursors. Examples include lignocellulosic biomass or other biological products derived from food or agricultural wastes (carbohydrates, cellulose, hemicellulose, lignin, chitin, inorganics, and proteins). Thermochemical conversion of biomass, including pyrolysis in an inert environment, has been developed for the production of energy and carbon materials. Furthermore, it is still a potential challenge to simultaneously produce high-quality biofuel products and synthesize value-added functionalized materials via in situ carbothermal reduction. This review will be a powerful resource for stimulating the development of sustainable metal-functionalized nanostructured materials by carbothermal reduction integrated with other advanced technologies, particularly for strengthening efforts towards novel materials for clean energy and environmental applications in the future sustainable society.