Anumber of studies have investigated the effects of stress on mental health and cardiovascular diseases and the relationship between stress and various components of the immune system, and they found that chronic stre...Anumber of studies have investigated the effects of stress on mental health and cardiovascular diseases and the relationship between stress and various components of the immune system, and they found that chronic stress is associated with suppression of a variety of immune parameters. However, acute stress is often associated with transient increases in immune activationl A few studies have also examined the slgA response to occupational stress. Zeier et al2 measured salivary slgA in air traffic controllers before and immediately after radar working sessions lasting approximately 100 minutes. Counter to the author＇s expectation, slgA was significantly elevated after the stressful work-session. Ng et al3 found slgA correlated inversely with self-reported levels of stress among nurses in Singapore. In the United States and Australia, studies on occupational stress in the nursing profession using salivary IgA as a stress indicator have also been conducted. Both studies indicated that the nurses＇ stress was significantly associated with a decreased salivary IgA secretion rates.4.5 A study has indicated salivary lysozyme as a promising marker of the effects of stress on nonspecific immunity, demonstrating a negative relation between perceived stress, as indicated by a stress score obtained by means of a questionnaire, and actual stress in the form of an undergraduate examination and salivary lysozyme levels.6 Ng et al3 have not found a relationship between salivary lysozyme levels and self-reported levels of stress among nurses in Singapore.展开更多
The analysis of the coupling mechanism of thermal-hydraulic-mechanical(THM)fields,and solid-liquidgas(SLG)phases during gas extraction process is of profound significance to explore its numerical application in the ga...The analysis of the coupling mechanism of thermal-hydraulic-mechanical(THM)fields,and solid-liquidgas(SLG)phases during gas extraction process is of profound significance to explore its numerical application in the gas occurrence regularity and its effective extraction radius.In this study,the Hudi coal mine in Qinshui basin is taken as the research area,the influencing factors of gas occurrence were analyzed,the differences in overburden load for gas pressure distribution and the factors influencing the effective extraction radius were further discussed by using the COMSOL software.The results show that the derivation of mathematical model in gas extraction shows that the process is a process the THM fields restrict each other,and the SLG phases influence each other.The longer the extraction time,the larger the influencing range of borehole,and the better the extraction effect.The larger the diameter of borehole,the larger the effective extraction radius,and the influence on gas extraction effect is smaller in the early stage and larger in the late stage.The borehole arrangement should be flexibly arranged according to the actual extraction situation.The higher the porosity,the higher the permeability,the better the gas extraction effect.The larger the overburden load of reservoir,the stronger the effective stress,which will result in the more severe the strain,and the closure of pore and fracture,which in turn will lead to the decrease of permeability and slow down the gas extraction.The relationship among extraction time,borehole diameter,negative pressure of gas extraction,permeability with effective extraction radius is exponential.This study has important theoretical and practical significance for clarifying and summarizing the gas occurrence regularity and its engineering practice.展开更多
:A new accurate algorithms based on mathematical modeling of two parallel transmissions lines system(TPTLS)as influenced by the mutual effect to determine the fault location is discussed in this work.The distance rela...:A new accurate algorithms based on mathematical modeling of two parallel transmissions lines system(TPTLS)as influenced by the mutual effect to determine the fault location is discussed in this work.The distance relay measures the impedance to the fault location which is the positive-sequence.The principle of summation the positive-,negative-,and zero-sequence voltages which equal zero is used to determine the fault location on the TPTLS.Also,the impedance of the transmission line to the fault location is determined.These algorithms are applied to single-line-to-ground(SLG)and double-line-to-ground(DLG)faults.To detect the fault location along the transmission line,its impedance as seen by the distance relay is determined to indicate if the fault is within the relay’s reach area.TPTLS under study are fed from one-and both-ends.A schematic diagrams are obtained for the impedance relays to determine the fault location with high accuracy.展开更多
Using molecular dynamics （MD） simulations, we have investigated the kinetics of the graphene edge folding process. The lower limit of the energy barrier is found to be -380 meV/A （or about 800 meV per edge atom） a...Using molecular dynamics （MD） simulations, we have investigated the kinetics of the graphene edge folding process. The lower limit of the energy barrier is found to be -380 meV/A （or about 800 meV per edge atom） and -50 meV/A （or about 120 meV per edge atom） for folding the edges of intrinsic clean single-layer graphene （SLG） and double-layer graphene （DLG）, respectively. However, the edge folding barriers can be substantially reduced by imbalanced chemical adsorption, such as of H atoms, on the two sides of graphene along the edges. Our studies indicate that thermal folding is not feasible at room temperature （RT） for clean SLG and DLG edges and is feasible at high temperature only for DLG edges, whereas chemical folding （with adsorbates） of both SLG and DLG edges can be spontaneous at RT. These findings suggest that the folded edge structures of suspended graphene observed in some experiments are possibly due to the presence of adsorbates at the edges.展开更多
文摘Anumber of studies have investigated the effects of stress on mental health and cardiovascular diseases and the relationship between stress and various components of the immune system, and they found that chronic stress is associated with suppression of a variety of immune parameters. However, acute stress is often associated with transient increases in immune activationl A few studies have also examined the slgA response to occupational stress. Zeier et al2 measured salivary slgA in air traffic controllers before and immediately after radar working sessions lasting approximately 100 minutes. Counter to the author＇s expectation, slgA was significantly elevated after the stressful work-session. Ng et al3 found slgA correlated inversely with self-reported levels of stress among nurses in Singapore. In the United States and Australia, studies on occupational stress in the nursing profession using salivary IgA as a stress indicator have also been conducted. Both studies indicated that the nurses＇ stress was significantly associated with a decreased salivary IgA secretion rates.4.5 A study has indicated salivary lysozyme as a promising marker of the effects of stress on nonspecific immunity, demonstrating a negative relation between perceived stress, as indicated by a stress score obtained by means of a questionnaire, and actual stress in the form of an undergraduate examination and salivary lysozyme levels.6 Ng et al3 have not found a relationship between salivary lysozyme levels and self-reported levels of stress among nurses in Singapore.
基金financially supported by the University Synergy Innovation Program of Anhui Province(No.GXXT-2021-018)the National Natural Science Foundation of China(No.42102217)+3 种基金the Natural Science Research Project of Anhui University(Nos.KJ2020A0315,KJ2020A0317)the Institute of Energy,Hefei Comprehensive National Science Center(No.21KZS218)the Natural Science Foundation of Anhui Province(No.2108085MD134)the Foundation of State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing(No.PRP/open-2005)
文摘The analysis of the coupling mechanism of thermal-hydraulic-mechanical(THM)fields,and solid-liquidgas(SLG)phases during gas extraction process is of profound significance to explore its numerical application in the gas occurrence regularity and its effective extraction radius.In this study,the Hudi coal mine in Qinshui basin is taken as the research area,the influencing factors of gas occurrence were analyzed,the differences in overburden load for gas pressure distribution and the factors influencing the effective extraction radius were further discussed by using the COMSOL software.The results show that the derivation of mathematical model in gas extraction shows that the process is a process the THM fields restrict each other,and the SLG phases influence each other.The longer the extraction time,the larger the influencing range of borehole,and the better the extraction effect.The larger the diameter of borehole,the larger the effective extraction radius,and the influence on gas extraction effect is smaller in the early stage and larger in the late stage.The borehole arrangement should be flexibly arranged according to the actual extraction situation.The higher the porosity,the higher the permeability,the better the gas extraction effect.The larger the overburden load of reservoir,the stronger the effective stress,which will result in the more severe the strain,and the closure of pore and fracture,which in turn will lead to the decrease of permeability and slow down the gas extraction.The relationship among extraction time,borehole diameter,negative pressure of gas extraction,permeability with effective extraction radius is exponential.This study has important theoretical and practical significance for clarifying and summarizing the gas occurrence regularity and its engineering practice.
文摘:A new accurate algorithms based on mathematical modeling of two parallel transmissions lines system(TPTLS)as influenced by the mutual effect to determine the fault location is discussed in this work.The distance relay measures the impedance to the fault location which is the positive-sequence.The principle of summation the positive-,negative-,and zero-sequence voltages which equal zero is used to determine the fault location on the TPTLS.Also,the impedance of the transmission line to the fault location is determined.These algorithms are applied to single-line-to-ground(SLG)and double-line-to-ground(DLG)faults.To detect the fault location along the transmission line,its impedance as seen by the distance relay is determined to indicate if the fault is within the relay’s reach area.TPTLS under study are fed from one-and both-ends.A schematic diagrams are obtained for the impedance relays to determine the fault location with high accuracy.
文摘Using molecular dynamics （MD） simulations, we have investigated the kinetics of the graphene edge folding process. The lower limit of the energy barrier is found to be -380 meV/A （or about 800 meV per edge atom） and -50 meV/A （or about 120 meV per edge atom） for folding the edges of intrinsic clean single-layer graphene （SLG） and double-layer graphene （DLG）, respectively. However, the edge folding barriers can be substantially reduced by imbalanced chemical adsorption, such as of H atoms, on the two sides of graphene along the edges. Our studies indicate that thermal folding is not feasible at room temperature （RT） for clean SLG and DLG edges and is feasible at high temperature only for DLG edges, whereas chemical folding （with adsorbates） of both SLG and DLG edges can be spontaneous at RT. These findings suggest that the folded edge structures of suspended graphene observed in some experiments are possibly due to the presence of adsorbates at the edges.
