Traditional coal mining and utilisation patterns are severely detrimental to natural resources and environments and significantly impede safe, low-carbon, clean, and sustainable utilisation of coal resources. Based on...Traditional coal mining and utilisation patterns are severely detrimental to natural resources and environments and significantly impede safe, low-carbon, clean, and sustainable utilisation of coal resources. Based on the idea of in situ fluidized coal mining that aims to transform solid coal into liquid or gas and transports the fluidized resources to the ground to ensure safe mining and low-carbon and clean utilisation, in this study, we report on a novel in situ unmanned automatic mining method. This includes a flexible, earthworm-like unmanned automatic mining machine (UAMM) and a coal mine layout for in situ fluidized coal mining suitable for the UAMM. The technological and economic advantages and the carbon emission reduction of the UAMM-based in situ fluidized mining in contrast to traditional mining technologies are evaluated as well. The development trends and possible challenges to this design are also discussed. It is estimated that the proposed method costs approximately 49% of traditional coal mining costs. The UAMM-based in situ fluidized mining and transformation method will reduce CO2 emissions by at least 94.9% compared to traditional coal mining and utilisation methods. The proposed approach is expected to achieve safe and environmentally friendly coal mining as well as lowcarbon and clean utilisation of coal.展开更多
The purpose of this study is to investigate the entire evolution process of shales with various total organic contents(TOC)in order to build models for quantitative evaluation of oil and gas yields and establish metho...The purpose of this study is to investigate the entire evolution process of shales with various total organic contents(TOC)in order to build models for quantitative evaluation of oil and gas yields and establish methods for assessing recoverable oil and gas resources from in-situ conversion of organic matters in shale.Thermal simulation experiments under in-situ conversion conditions were conducted on Chang 7_(3) shales from the Ordos Basin in a semi-open system with large capacity.The results showed that TOC and R_(o) were the key factors affecting the in-situ transformation potential of shale.The remaining oil and gas yields increased linearly with TOC but inconsistently with R_(o).R_(o) ranged 0.75%—1.25%and 1.05%—2.3%,respectively,corresponding to the main oil generation stage and gas generation stage of shale in-situ transformation.Thus a model to evaluate the remaining oil/gas yield with TOC and R_(o) was obtained.The TOC of shale suitable for in-situ conversion should be greater than 6%,whereas its R_(o) should be less than 1.0%.Shales with 0.75%(R_(o))could obtain the best economic benefit.The results provided a theoretical basis and evaluation methodology for predicting the hydrocarbon resources from in-situ conversion of shale and for the identification of the optimum“sweet spots”.The assessment of the Chang 7_(3) shale in the Ordos Basin indicated that the recoverable oil and gas resources from in-situ conversion of organic matters in shale are substantial,with oil and gas resources reaching approximately 450×10^(8) t and 30×10^(12)m^(3),respectively,from an area of 4.27×10^(4) km^(2).展开更多
Total knee arthroplasty (TKR) is the most common and costly surgical procedure performed, and it is considered one of the most successful clinical interventions for patients suffering from severe knee osteoarthritis (...Total knee arthroplasty (TKR) is the most common and costly surgical procedure performed, and it is considered one of the most successful clinical interventions for patients suffering from severe knee osteoarthritis (OA). The incidence of TKR, including demographics, incidence rates, lengths of hospital stay, and costs, was estimated from 2010 to 2019 by analyzing data extracted from the Joint Surgery Department in our hospital, which included a total of 6770 patients. We calculated the TKR risk ratios to compare the rate of TKR between different covariables such as gender, age group, and primary diagnoses. The annual volume of TKR increased by fivefold (5.14%), with a higher incidence observed in the 60 to 69 age group constituting approximately 36% of cases. There has also been an increase in incidence among young people (<50), which now stands at 6.2%. The rate ratio (RR) per female vs. male was found to be 3.0 and the RR of OA vs. RA was 0.09. The mean average length of stay (ALOS) in the hospital decreased from 15 to just 5 days during this period. Additionally, the adjusted mean cost per patient increased significantly from ¥ 38261 ± 3630.63 to ¥ 53115.17 ± 2831.35. The majority of TKR recipients were over 60 years old with osteoarthritis being identified as the main causative agent. It is worth noting that women are more susceptible to knee arthritis and there is a concerning shift toward younger individuals being affected by this disease. Our results indicate a rise in in-hospital costs alongside a significant decline in hospital ALOS for TKR procedures. We predict an unprecedented rise in TKR incidence in the coming years due to population aging and improving economic conditions in China.展开更多
The analytical method of total resource reallocation effect is an evolution of the analytical method of the factors of economic growth. Since the marketization reform in China in 1978, market mechanism has played a mo...The analytical method of total resource reallocation effect is an evolution of the analytical method of the factors of economic growth. Since the marketization reform in China in 1978, market mechanism has played a more and more important role in resource allocation, and Chinese economy has developed greatly, which is called "the Chinese Miracle". This paper analyzes the economic growth in China from 1978 to 2004 with the analytical method of total resource reallocation effect. The result shows that the annual growth rate of total resource reallocation effect was 0.2%, which was 5.1% of the comprehensive productivity and 0.21% of the gross output growth, i.e. the total resource allocation played a weak role in the economic growth in China. When analyzing it in Chenery's multinational model, we find that Chinese comprehensive productivity growth rate was higher than that in all the income phases of the model, but the total resource allocation effect was obviously lower than that in all the income phases of the model. It indicates that the total resource allocation in China has a great potential, and that to accelerate marketization reform is one of the important issues for Chinese economic development.展开更多
基金The authors gratefully acknowledge the financial support provided by the State Key Research Development Program of China (Grant Number 2016YFC0600705)the National Natural Science Foundation of China (Grant Numbers 51674251, 51727807, and 51374213)+1 种基金the National Major Project for Science and Technology (Grant Number 2017ZX05049003-006)and the Innovation Teams of Ten-thousand Talents Program sponsored by the Ministry of Science and Technology of China (Grant Number 2016RA4067).
文摘Traditional coal mining and utilisation patterns are severely detrimental to natural resources and environments and significantly impede safe, low-carbon, clean, and sustainable utilisation of coal resources. Based on the idea of in situ fluidized coal mining that aims to transform solid coal into liquid or gas and transports the fluidized resources to the ground to ensure safe mining and low-carbon and clean utilisation, in this study, we report on a novel in situ unmanned automatic mining method. This includes a flexible, earthworm-like unmanned automatic mining machine (UAMM) and a coal mine layout for in situ fluidized coal mining suitable for the UAMM. The technological and economic advantages and the carbon emission reduction of the UAMM-based in situ fluidized mining in contrast to traditional mining technologies are evaluated as well. The development trends and possible challenges to this design are also discussed. It is estimated that the proposed method costs approximately 49% of traditional coal mining costs. The UAMM-based in situ fluidized mining and transformation method will reduce CO2 emissions by at least 94.9% compared to traditional coal mining and utilisation methods. The proposed approach is expected to achieve safe and environmentally friendly coal mining as well as lowcarbon and clean utilisation of coal.
基金supported by PetroChina Co Ltd.(Grant number:2015D-4810-02,2018YCQ03,2021DJ52)National Natural Science Foundation of China(Grant number:42172170)
文摘The purpose of this study is to investigate the entire evolution process of shales with various total organic contents(TOC)in order to build models for quantitative evaluation of oil and gas yields and establish methods for assessing recoverable oil and gas resources from in-situ conversion of organic matters in shale.Thermal simulation experiments under in-situ conversion conditions were conducted on Chang 7_(3) shales from the Ordos Basin in a semi-open system with large capacity.The results showed that TOC and R_(o) were the key factors affecting the in-situ transformation potential of shale.The remaining oil and gas yields increased linearly with TOC but inconsistently with R_(o).R_(o) ranged 0.75%—1.25%and 1.05%—2.3%,respectively,corresponding to the main oil generation stage and gas generation stage of shale in-situ transformation.Thus a model to evaluate the remaining oil/gas yield with TOC and R_(o) was obtained.The TOC of shale suitable for in-situ conversion should be greater than 6%,whereas its R_(o) should be less than 1.0%.Shales with 0.75%(R_(o))could obtain the best economic benefit.The results provided a theoretical basis and evaluation methodology for predicting the hydrocarbon resources from in-situ conversion of shale and for the identification of the optimum“sweet spots”.The assessment of the Chang 7_(3) shale in the Ordos Basin indicated that the recoverable oil and gas resources from in-situ conversion of organic matters in shale are substantial,with oil and gas resources reaching approximately 450×10^(8) t and 30×10^(12)m^(3),respectively,from an area of 4.27×10^(4) km^(2).
文摘Total knee arthroplasty (TKR) is the most common and costly surgical procedure performed, and it is considered one of the most successful clinical interventions for patients suffering from severe knee osteoarthritis (OA). The incidence of TKR, including demographics, incidence rates, lengths of hospital stay, and costs, was estimated from 2010 to 2019 by analyzing data extracted from the Joint Surgery Department in our hospital, which included a total of 6770 patients. We calculated the TKR risk ratios to compare the rate of TKR between different covariables such as gender, age group, and primary diagnoses. The annual volume of TKR increased by fivefold (5.14%), with a higher incidence observed in the 60 to 69 age group constituting approximately 36% of cases. There has also been an increase in incidence among young people (<50), which now stands at 6.2%. The rate ratio (RR) per female vs. male was found to be 3.0 and the RR of OA vs. RA was 0.09. The mean average length of stay (ALOS) in the hospital decreased from 15 to just 5 days during this period. Additionally, the adjusted mean cost per patient increased significantly from ¥ 38261 ± 3630.63 to ¥ 53115.17 ± 2831.35. The majority of TKR recipients were over 60 years old with osteoarthritis being identified as the main causative agent. It is worth noting that women are more susceptible to knee arthritis and there is a concerning shift toward younger individuals being affected by this disease. Our results indicate a rise in in-hospital costs alongside a significant decline in hospital ALOS for TKR procedures. We predict an unprecedented rise in TKR incidence in the coming years due to population aging and improving economic conditions in China.
文摘The analytical method of total resource reallocation effect is an evolution of the analytical method of the factors of economic growth. Since the marketization reform in China in 1978, market mechanism has played a more and more important role in resource allocation, and Chinese economy has developed greatly, which is called "the Chinese Miracle". This paper analyzes the economic growth in China from 1978 to 2004 with the analytical method of total resource reallocation effect. The result shows that the annual growth rate of total resource reallocation effect was 0.2%, which was 5.1% of the comprehensive productivity and 0.21% of the gross output growth, i.e. the total resource allocation played a weak role in the economic growth in China. When analyzing it in Chenery's multinational model, we find that Chinese comprehensive productivity growth rate was higher than that in all the income phases of the model, but the total resource allocation effect was obviously lower than that in all the income phases of the model. It indicates that the total resource allocation in China has a great potential, and that to accelerate marketization reform is one of the important issues for Chinese economic development.
