Mitigating Greenhouse Gas Emissions from Winter Production of Agricultural Greenhouses

Consuming conventional fossil fuel, such as coal, natural gas, and oil, to heat agricultural greenhouses has contributed to the climate change and air pollutions regionally and globally, so the clean energy sources have been increasingly applied to replace fossil energies in heating agricultural greenhouses, especially in urban area. To assess the environment performance (e.g., greenhouse gas (GHG) emissions) of the ground source heat pump system (GSHPs) for heating agricultural greenhouses in urban area, a GSHPs using the shallow geothermal energy (SGE) in groundwater was applied to heat a Chinese solar greenhouse (G1) and a multispan greenhouse (G2) in Beijing (latitude 39°40′ N), the capital city of China. Emission rates of the GSHPs for heating the G1 and G2 were quantified to be 0.257–0.879 g CO2 eq. m−2 day−1. The total GHG emissions from heating greenhouses in Beijing with the GSHPs were quantified as 1.7–2.9 Gt CO2 eq. year−1 based on the electricity from the coal-fired power plant (CFPP) and the gas-fired power plant (GFPP). Among different stages of the SGE flow, the SGE promotion contributed most GHG emissions (66%) in total due to the higher consumption of electricity in compressors. The total GHG emissions from greenhouses heating with the coal-fired heating system (CFHs) and gas-fired heating system (GFHs) were quantified as 2.3–5.2 Gt CO2 eq. year−1 in Beijing. Heating the G1 and G2 with the GSHPs powered by the electricity from the CFPP, the equivalent CO2 emissions were 43% and 44% lower than directly burning coal with the CFHs but were 46% and 44% higher than the GFHs that burn natural gas. However, when using the GFPP-generated electricity to run the GSHPs, the equivalent CO2 emissions would be 84% and 47% lower than the CFHs and the GFHs, respectively

Does China’s emission trading scheme affect corporate financial performance:Evidence from a quasi-natural experiment

Taking China’s emissions trading system (ETS) pilots as a quasi-natural experiment, we examine how the ETS affects firms’ financial performance. Previous studies highlight the impact of ETS on regional and industrial development; however, few studies focus on its potential impact on firms’ performance. Using a time-varying difference-in-differences model and data on Chinese listed firms from 2008 to 2020, we find that the ETS pilots have significant positive impacts on firms’ profitability and value and a negative impact on operating costs. We also find that the ETS pilots improve total factor productivity, but the technological changes indirectly suppress the relation between the ETS and financial performance. Finally, we find evidence that state-owned enterprises experience more significant improvements in their financial performance, led by ETS participation. Our findings have policy implications for firms’ sustainable development and the transition to a low-carbon economy

Evaluation of the deposition and distribution of spray droplets in citrus orchards by plant protection drones

Plant protection drone spraying technology is widely used to prevent and control crop diseases and pests due to its advantages of being unaffected by crop growth patterns and terrain restrictions, high operational efficiency, and low labor requirements. The operational parameters of plant protection drones significantly impact the distribution of spray droplets, thereby affecting pesticide utilization. In this study, a field experiment was conducted to determine the working modes of two representative plant protection drones and an electric backpack sprayer as a control to explore the characteristics of droplet deposition with different spray volumes in the citrus canopy. The results showed that the spraying volume significantly affected the number of droplets and the spray coverage. The number of droplets and the spray coverage area on the leaf surface were significantly increased by increasing the spray volume from 60 L/ha to 120 L/ha in plant protection drones. Particularly for the DJI T30, the mid-lower canopy showed a spray coverage increase of 52.5%. The droplet density demonstrated the most significant variations in the lower inner canopy, ranging from 18.7 droplets/cm2 to 41.7 droplets/cm2 by XAG V40. From the deposition distribution on fruit trees, the plant protection drones exhibit good penetration ability, as the droplets can achieve a relatively even distribution in different canopy layers of citrus trees. The droplet distribution uniformity inside the canopy is similar for XAG V40 and DJI T30, with a variation coefficient of approximately 50%-100%. Compared to the plant protection drones, the knapsack electric sprayer is suitable for pest and disease control in the mid-lower canopy, but they face challenges of insufficient deposition capability in the upper canopy and overall poor spray uniformity. The distribution of deposition determined in this study provides data support for the selection of spraying agents for fruit trees by plant protection drones and for the control of different pests and diseases

Woodchuck hepatitis virus core antigen-based DNA and protein vaccines induce qualitatively different immune responses that affect T cell recall responses and antiviral effects

AbstractT helper type 1 (Th1) immunity was considered to play a dominant role in viral clearance of hepadnaviral infection. However, pre-primed Th2 type responses were able to efficiently control hepadnaviral infection in animal models. We investigated how pre-primed Th1/2 responses control hepadnaviral replication using the newly established mouse models. DNA (pWHcIm, pCTLA-4-C) and protein vaccines based on the nucleocapsid protein (WHcAg) of woodchuck hepatitis virus (WHV) primed specific immune responses with distinct features. The pre-primed responses determined the characteristics of recall responses if challenged with a WHcAg-expressing adenoviral vector. Vaccination with pWHcIm and pCTLA4-C facilitated viral control in the hydrodynamic injection model and reduced WHV loads by about 3 and 2 logs in WHV-transgenic mice, respectively, despite of different kinetics of specific CD8+ T cell responses. Thus, pre-primed Th2-biased responses facilitate the development of CD8+ T cell responses in mice compared with naïve controls and thereby confer better viral control

A Continuously Tunable and Filter-Less QPSK Modulated Millimeter-Wave Signal Generation with Frequency Quadrupling Just Based on an MZM

In this paper, we propose a new frequency quadrupling scheme to generate a quadrature phase shift keying (QPSK) modulated vector millimeter-wave signal, in which an optical filter is not necessary. To eliminate constellation overlapping of the generated vector millimeter-wave signal caused by phase multiplication in the process of frequency multiplication, a precoding assisted technique is adopted. The principle and feasibility of the proposed scheme is deduced by a detailed mathematical formula. Simulations are carried out to generate 40 GHz QPSK modulated vector millimeter-wave signals using a 10 GHz radio frequency source and the BER performance is analyzed in detail. The results show that BER of the generated 5/10-Gbaud vector millimeter-wave signal is below 3.8×10-3, when the input optical power for into photo-detector is higher than −20.67 dBm

Establishment and application of in vitro and in vivo models of hepatitis B virus infection

Hepatitis B is still an important infectious disease which threatens human health, and current antiviral therapy, including interferon and nucleos(t)ide analogues, cannot cure chronic hepatitis B. Therefore, it is urgent to explore the detail mechanisms of HBV replication and pathogenesis, identify new therapeutic targets, and develop new drugs or treatment regimens, which relies on the development of suitable models for HBV infection and replication. Species restriction and tissue tropism of HBV have limited the development of models for HBV infection and replication. With the support by National Science and Technology Major Project for Infectious Diseases, the researchers in China have developed a series of cellular and animal models for HBV. This article reviews these models with reference to recent research advances in China and foreign countries

On the downlink throughput capacity of hybrid wireless networks with massive MIMO

Abstract In this paper, the entire network model is a hybrid wireless network model in which each base station is connected to each other via a wired link. On this basis, we place a large number of antennas (massive MIMO) at each base station to serve a single terminal in the downlink scenario, and we research the outage capacity and ergodic capacity in this scenario. The result of this paper is that the expressions for ergodic throughput capacity, outage probability, and outage throughput capacity have been derived under the favorable propagation condition. Through simulation, we can see the trend of outage throughput capacity and ergodic throughput capacity

4th International Conference on Communications, Signal Processing, and Systems

This book brings together papers presented at the 4th International Conference on Communications, Signal Processing, and Systems, which provides a venue to disseminate the latest developments and to discuss the interactions and links between these multidisciplinary fields. Spanning topics ranging from Communications, Signal Processing and Systems, this book is aimed at undergraduate and graduate students in Electrical Engineering, Computer Science and Mathematics, researchers and engineers from academia and industry as well as government employees (such as NSF, DOD, DOE, etc)