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574 results on '"Liu, Yanguang"'

107. Predicting the sound speed of seafloor sediments in the Middle area of the Southern Yellow Sea based on a BP neural network model.

Author

Chen, Mujun, Meng, Xiangmei, Kan, Guangming, Wang, Jingqiang, Li, Guanbao, Liu, Baohua, Liu, Chenguang, Liu, Yanguang, and Meng, Wenjing

Subjects
SPEED of sound, SEDIMENTS, SEDIMENT sampling
Abstract

Based on the data of the sound speed and the physical–mechanical properties of 300 seafloor sediment samples collected in the middle area of the Southern Yellow Sea, a backpropagation (BP) neural network algorithm is used herein to study the neural network topology and the corresponding neuron characteristic factors. A neural network model for predicting the sound speed of the seafloor sediment based on density, water content, porosity, void ratio, liquid limit, plastic limit, and clay content in the middle area of the Southern Yellow Sea is established. The results show that the sound speed prediction accuracy is the highest when the network model contains seven input layer neurons, ten hidden layer neurons, and one output node. According to the prediction results, the MAE(Mean Absolute Error) and the MAPE(Mean Absolute Percentage Error) are 13.19 m s−1 and 0.85%, respectively. The prediction results illustrate that the established BP neural network prediction method for the seafloor sediment sound speed is better than the traditional single, two and multi-parameter prediction equations. [ABSTRACT FROM AUTHOR]

Published
2023
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128. Occurrence of geothermal resources and prospects for exploration and development in China

Author

Guiling Wang, Li Tingxin, Xi Zhu, and Liu Yanguang

Subjects
Renewable Energy, Sustainability and the Environment, lcsh:TJ807-830, 05 social sciences, lcsh:Renewable energy sources, Energy Engineering and Power Technology, 010502 geochemistry & geophysics, 01 natural sciences, ComputingMilieux_GENERAL, lcsh:Production of electric energy or power. Powerplants. Central stations, Energy conservation, Fuel Technology, Nuclear Energy and Engineering, Environmental protection, lcsh:TK1001-1841, 0502 economics and business, Environmental science, Energy structure, China, Geothermal gradient, 050212 sport, leisure & tourism, 0105 earth and related environmental sciences
Abstract

Under the background of China’s energy structure optimization, environmental protection, energy conservation, and rising pressure of emission reduction, geothermal, as a potential strategic replacement energy, has ushered in new opportunities and challenges. This paper systematically summarizes the domestic achievements in the exploration and development of geothermal resources, analyzes the endowment, distribution, and accumulation mechanism of geothermal resources in China, and points out the main problems existing in the exploration and development of geothermal resources in China. On this basis, it looks forward to China’s urgent geothermal exploration and development work and key technologies to be urgently developed, providing important guidance for China’s geothermal science and technology innovation and rapid industrialization development.

Published
2019

129. Influence of low temperature tail water reinjection on seepage and heat transfer of carbonate reservoirs

Author

Wang Yan, Bian Kai, Liu Yanguang, Shenjun Qin, Wanli Wang, Zhang Hongyun, Hong Zhang, and Xiaojun Wang

Subjects
TK1001-1841, Materials science, Computer simulation, Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, TJ807-830, Mechanics, Renewable energy sources, Coupling (electronics), chemistry.chemical_compound, Fuel Technology, Production of electric energy or power. Powerplants. Central stations, Nuclear Energy and Engineering, chemistry, Scientific method, Heat transfer, Carbonate
Abstract

Seepage and heat transfer in the carbonate reservoir under low-temperature tail water reinjection is a complex coupling process, which is an important basis for scientific and reasonable evaluation of geothermal resource sustainability. This study based on the tracer test of double-well reinjection for carbonate heat reservoir, a coupling model of seepage field and temperature field of fracture network is established by using the finite element software COMSOL. The uncertainty analysis is carried out to study the fluid-thermal coupling process of carbonate fracture under the condition of low-temperature tail water reinjection.The variation law of seepage field and temperature field of thermal reservoir under low-temperature geothermal tail water reinjection is revealed, The variation of measured temperature of thermal reservoir pumping side under different reinjection conditions is predicted. The results show that the dominant fracture channels between wells of the fractured heat reservoir in Xian county geothermal field play an important role in controlling the seepage heat transfer. Under the coupling action of the seepage field, pressure field and the temperature field of the heat reservoir, the low-temperature tail water reinjection forms a preferential flow along the dominant channels, which is one of the important factors to consider in the prediction of thermal breakthrough. Reinjection pressure, temperature and well spacing are the main factors for artificial control of geothermal production and reinjection system. In the pumping and reinjection system of Xian county geothermal field, under the conditions of 0.5 MPa reinjection pressure, 30 °C reinjection tail water temperature and 270 m spacing between pumping and reinjection wells, the heat reservoir temperature at the pumping side decreased by 1.5 °C in 100 years.

Published
2021

137. Economic agglomeration and product quality upgrading: evidence from China.

Author

Zhou, Dinggen, Liu, Yanguang, Ren, Xiaohang, Yan, Cheng, and Shi, Yukun

Abstract

Based on merged custom import and export data and Chinese industrial enterprise data, this paper studies the influence of economic agglomeration incurred by urbanization in China on the products' quality upgrading. We find that economic agglomeration can improve the product quality of Chinese enterprises. We further show that in the context of deepening trade liberalization, economic agglomeration leads enterprises to import more various intermediate products, thus helping to upgrade the quality of final products. The increase in the proportion of intermediate products imported from high-income countries will strengthen the role of economic agglomeration in upgrading the quality of products. [ABSTRACT FROM AUTHOR]

Published
2022
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143. Isotopic Records of Ancient Wildfires in C4 Grasses Preserved in the Sediment of the Ross Sea, Antarctica.

Author

Ren, Peng, Luo, Chunle, Zhang, Hongmei, Cui, Chao, Sun, Shuwen, Song, Hongying, Xu, Liping, Rebesco, Michele, De Santis, Laura, Liu, Yanguang, and Wang, Xuchen

Subjects
CARBON isotopes, WILDFIRES, SEDIMENTS, STABLE isotopes, BIOMASS burning, WILDFIRE prevention
Abstract

We report carbon isotopic values in total organic carbon (TOC) and pyrogenic carbon (PyC) preserved in two sediment cores from the Ross Sea, Antarctica. The δ13C values of PyC ranged from −10.9‰ to −17.2‰, with distinct differences from the δ13C values of TOC (−24.1‰ to −26.1‰) in the sediments. The radiocarbon ages of PyC were 9,128 and 8,410 years old on average in the two cores but were thousands of years younger than the ages of TOC at the same core depth. These isotopic records provide strong evidence indicating that the PyC was produced from ancient wildfires predominantly in C4 vegetation and transported to Antarctica in the atmosphere. We suggest that ancient wildfires in predominantly C4 grasslands likely frequently occurred on a large scale and at a high intensity in the Southern Hemisphere during the last deglaciation to mid‐Holocene period of 14,800–4,200 years ago. Plain Language Summary: A large fraction of pyrogenic carbon (PyC) is produced from incomplete combustion of biomass fires on Earth and is widely distributed on land and in the oceans. This study presents the first evidence of both radiocarbon and stable carbon isotopes in the PyC preserved in the slope sediments of the Ross Sea in Antarctica. The results revealed that PyC accounted for a significant fraction (10.0%–28.0%) of the sedimentary total organic carbon (TOC) buried in the sediments, and both the Δ14C and δ13C values of PyC showed distinctive differences compared with those of TOC. The well‐defined δ13C (−10.9‰ to −17.2‰) and Δ14C (−415‰ to −843‰) values of PyC in the sediments revealed that in ancient times, PyC was produced from wildfires of C4 vegetation in the Southern Hemisphere and was transported in the atmosphere to Antarctica. The isotopic records of PyC preserved in the Ross Sea sediments provide meaningful evidence for environmental changes. Key Points: Pyrogenic carbon (PyC) constitutes a significant fraction of total organic carbon (TOC) preserved in sediment of the Ross Sea, AntarcticaDistinctive differences in both radiocarbon and stable carbon isotope values exist between PyC and TOC in the Ross Sea sedimentThe isotopic records indicated that the PyC was produced from ancient wildfires in C4 grasslands and transported to Antarctica in atmosphere [ABSTRACT FROM AUTHOR]

Published
2022
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