Under submerged conditions, compared with traditional self-excited oscillating pulsed waterjets(SOPWs), annular fluid-enhanced self-excited oscillating pulsed waterjets(AFESOPWs) exhibit a higher surge pressure throug...Under submerged conditions, compared with traditional self-excited oscillating pulsed waterjets(SOPWs), annular fluid-enhanced self-excited oscillating pulsed waterjets(AFESOPWs) exhibit a higher surge pressure through self-priming. However, their pressure frequency and cavitation characteristics remain unclear, resulting in an inability to fully utilize resonance and cavitation erosion to break coal and rock. In this study, high-frequency pressure testing, high-speed photography, and large eddy simulation(LES) are used to investigate the distribution of the pressure frequency band, evolution law of the cavitation cloud, and its regulation mechanism of a continuous waterjet, SOPW, and AFESOPW. The results indicated that the excitation of the plunger pump, shearing layer vortex, and bubble collapse corresponded to the three high-amplitude frequency bands of the waterjet pressure. AFESOPWs have an additional self-priming frequency that can produce a larger amplitude under a synergistic effect with the second high-amplitude frequency band. A better cavitation effect was produced after self-priming the annulus fluid, and the shedding frequency of the cavitation clouds of the three types of waterjets was linearly related to the cavitation number. The peak pressure of the waterjet and cavitation erosion effect can be improved by modulating the waterjet pressure oscillation frequency and cavitation shedding frequency.展开更多
Predicting tropical cyclone(TC)genesis is of great societal importance but scientifically challenging.It requires fineresolution coupled models that properly represent air−sea interactions in the atmospheric responses...Predicting tropical cyclone(TC)genesis is of great societal importance but scientifically challenging.It requires fineresolution coupled models that properly represent air−sea interactions in the atmospheric responses to local warm sea surface temperatures and feedbacks,with aid from coherent coupled initialization.This study uses three sets of highresolution regional coupled models(RCMs)covering the Asia−Pacific(AP)region initialized with local observations and dynamically downscaled coupled data assimilation to evaluate the predictability of TC genesis in the West Pacific.The APRCMs consist of three sets of high-resolution configurations of the Weather Research and Forecasting−Regional Ocean Model System(WRF-ROMS):27-km WRF with 9-km ROMS,and 9-km WRF with 3-km ROMS.In this study,a 9-km WRF with 9-km ROMS coupled model system is also used in a case test for the predictability of TC genesis.Since the local sea surface temperatures and wind shear conditions that favor TC formation are better resolved,the enhanced-resolution coupled model tends to improve the predictability of TC genesis,which could be further improved by improving planetary boundary layer physics,thus resolving better air−sea and air−land interactions.展开更多
In 2012,the International Agency for Research on Cancer(IARC)classified diesel particulate matter(DPM)as a carcinogen to human.With the increased usage of diesel equipment in underground mines,miners have a high risk ...In 2012,the International Agency for Research on Cancer(IARC)classified diesel particulate matter(DPM)as a carcinogen to human.With the increased usage of diesel equipment in underground mines,miners have a high risk of over-exposure to DPM,which has drawn many concerns from the public.This study used computational fluid dynamics(CFD)to analyse the DPM dispersion and concentration distribution characteristics in an underground development face based on an onsite experiment.The DPM emitted from a moving loader under a forcing auxiliary ventilation system was simulated.The motion of the load-haul-dump(LHD)in the tunnel was represented by a dynamic mesh method.The species transport approach was applied to study the DPM behaviours.High DPM concentration zones were then identified based on the simulation results.The results could provide guidelines for work practices and be helpful to an optimum auxiliary ventilation design to reduce underground miner exposure.展开更多
Background:The ossification mechanism of the temporomandibular joint(TMJ)condyle remains unclear in human embryo.The size and structure of TMJ,shape of articular disc and the characteristics of omnivorous chewing in t...Background:The ossification mechanism of the temporomandibular joint(TMJ)condyle remains unclear in human embryo.The size and structure of TMJ,shape of articular disc and the characteristics of omnivorous chewing in the pig are similar to those of humans.The pig is an ideal animal for studying the mechanism of ossification of the TMJ condyle during the embryonic period.Method:In a previous study by our group,it was found that there was no condylar ossification on embryonic day(E)45,but the ossification of condyle occurred between E75 and E90.In this study,a total of 12 miniature pig embryos on E45 and E85 were used.Six embryos were used for tissue sections(3 in each group).The remaining six embryos were used for transcriptomic and proteomic studies to find differential genes and proteins.The differentially expressed genes in transcriptome and proteomic analysis were verified by QPCR.Results:In total,1592 differential genes comprising 1086 up-regulated genes and 506 down-regulated genes were screened for fold changes of≥2 to≤0.5 between E45 and E85.In the total of 4613 proteins detected by proteomic analysis,there were 419 differential proteins including 313 up-regulated proteins and 106 down-regulated proteins screened for fold changes of≥2 to≤0.5 between E45 and E85.A total of 36 differential genes differing in both transcriptome and proteome analysis were found.QPCR analysis showed that 14 of 15 selected genes were consistent with transcriptome analysis.Conclusion:Condylar transcriptome and proteomic analysis during the development of TMJ in miniature pigs revealed the regulatory genes/proteins of condylar ossification.展开更多
Four ground cover plant species of Taiyuan(Iris,Hemerocallis,Sedum,Hosta)were selected to study their capacities in adsorbing PM_(2.5).Meanwhile,the concentration of PM(2.5)in Taiyuan between April 2017 and August 201...Four ground cover plant species of Taiyuan(Iris,Hemerocallis,Sedum,Hosta)were selected to study their capacities in adsorbing PM_(2.5).Meanwhile,the concentration of PM(2.5)in Taiyuan between April 2017 and August 2017 was recorded,and the characteristics of PM_(2.5)pollution in summer and autumn in Taiyuan were studied.The results showed that for the 4 plants,the ability to adsorb PM_(2.5)was in the order from great to small of Hosta,Iris,Hemerocallis,Sedum,in which H.plantaginea had the best effect to adsorb PM_(2.5).The fresh weight and dry weight per gram of H.plantaginea were 4.4 times and 2 times higher than those of S.spectabile,while the mass quality of dust adsorption was 2.8 times higher.The sorting result was the same as the ability to adsorb PM_(2.5)of unit leaf area.The result of the coefficient of purification showed that the purification coefficients of 3 vegetation structure were positive,and the combination of trees and shrubs in university campus had strong PM_(2.5)adsorption capacity.By comparing the seasonal variation of PM_(2.5)concentration in Taiyuan city,it found that the PM_(2.5)concentration was particularly high in late spring and early summer of Taiyuan,when most of the ground cover plants were not fully grown.Therefore,ground cover plants played an important role in the construction of landscape and the regulation of ecological environment in Taiyuan.展开更多
The reliability of energy systems is strongly influenced by the prevailing climate conditions.With the increasing prevalence of renewable energy sources,the interdependence between energy and climate systems has becom...The reliability of energy systems is strongly influenced by the prevailing climate conditions.With the increasing prevalence of renewable energy sources,the interdependence between energy and climate systems has become even stronger.This study examines the impact of different spatial resolutions in climate modeling on energy grid reliability assessment,with the Texas interconnection between 2033 and 2043 serving as a pilot case study.Our preliminary findings indicate that while low-resolution climate simulations can provide a rough estimate of system reliability,high-resolution simulations can provide more informative assessment of low-adequacy extreme events.Furthermore,both high-and low-resolution assessments suggest the need to prepare for severe blackout events in winter due to extremely low temperatures.展开更多
A regional coupled prediction system for the Asia-Pacific(AP-RCP)(38°E-180°,20°S-60°N) area has been established.The AP-RCP system consists of WRF-ROMS(Weather Research and Forecast,and Regional Oc...A regional coupled prediction system for the Asia-Pacific(AP-RCP)(38°E-180°,20°S-60°N) area has been established.The AP-RCP system consists of WRF-ROMS(Weather Research and Forecast,and Regional Ocean Model System) coupled models combined with local observational information through dynamically downscaling coupled data assimilation(CDA).The system generates 18-day forecasts for the atmosphere and ocean environment on a daily quasi-operational schedule at Pilot National Laboratory for Marine Science and Technology(Qingdao)(QNLM),consisting of 2 different-resolution coupled models:27 km WRF coupled with 9 km ROMS,9 km WRF coupled with 3 km ROMS,while a version of 3 km WRF coupled with 3 km ROMS is in a test mode.This study is a first step to evaluate the impact of high-resolution coupled model with dynamically downscaling CDA on the extended-range predictions,focusing on forecasts of typhoon onset,improved precipitation and typhoon intensity forecasts as well as simulation of the Kuroshio current variability associated with mesoscale oceanic activities.The results show that for realizing the extended-range predictability of atmospheric and oceanic environment characterized by statistics of mesoscale activities,a fine resolution coupled model resolving local mesoscale phenomena with balanced and coherent coupled initialization is a necessary first step.The next challenges include improving the planetary boundary physics and the representation of air-sea and air-land interactions to enable the model to resolve kilometer or sub-kilometer processes.展开更多
基金supported by the program for National Natural Science Foundation of China (Nos. 52174173, 52274188, and 52104190)the Joint Funds of the National Natural Science Foundation of China (No. U24A2091)+1 种基金The Natural Science Foundation of Henan Polytechnic University (No. B2021-2)Double FirstClass Initiative of Safety and Energy Engineering (Henan Polytechnic University) (Nos. AQ20240703 and AQ20230304)。
文摘Under submerged conditions, compared with traditional self-excited oscillating pulsed waterjets(SOPWs), annular fluid-enhanced self-excited oscillating pulsed waterjets(AFESOPWs) exhibit a higher surge pressure through self-priming. However, their pressure frequency and cavitation characteristics remain unclear, resulting in an inability to fully utilize resonance and cavitation erosion to break coal and rock. In this study, high-frequency pressure testing, high-speed photography, and large eddy simulation(LES) are used to investigate the distribution of the pressure frequency band, evolution law of the cavitation cloud, and its regulation mechanism of a continuous waterjet, SOPW, and AFESOPW. The results indicated that the excitation of the plunger pump, shearing layer vortex, and bubble collapse corresponded to the three high-amplitude frequency bands of the waterjet pressure. AFESOPWs have an additional self-priming frequency that can produce a larger amplitude under a synergistic effect with the second high-amplitude frequency band. A better cavitation effect was produced after self-priming the annulus fluid, and the shedding frequency of the cavitation clouds of the three types of waterjets was linearly related to the cavitation number. The peak pressure of the waterjet and cavitation erosion effect can be improved by modulating the waterjet pressure oscillation frequency and cavitation shedding frequency.
基金supported by the National Key Research&Development Program of China(Grant Nos.2017YFC1404100 and 2017YFC1404104)the National Natural Science Foundation of China(Grant Nos.41775100 and 41830964)。
文摘Predicting tropical cyclone(TC)genesis is of great societal importance but scientifically challenging.It requires fineresolution coupled models that properly represent air−sea interactions in the atmospheric responses to local warm sea surface temperatures and feedbacks,with aid from coherent coupled initialization.This study uses three sets of highresolution regional coupled models(RCMs)covering the Asia−Pacific(AP)region initialized with local observations and dynamically downscaled coupled data assimilation to evaluate the predictability of TC genesis in the West Pacific.The APRCMs consist of three sets of high-resolution configurations of the Weather Research and Forecasting−Regional Ocean Model System(WRF-ROMS):27-km WRF with 9-km ROMS,and 9-km WRF with 3-km ROMS.In this study,a 9-km WRF with 9-km ROMS coupled model system is also used in a case test for the predictability of TC genesis.Since the local sea surface temperatures and wind shear conditions that favor TC formation are better resolved,the enhanced-resolution coupled model tends to improve the predictability of TC genesis,which could be further improved by improving planetary boundary layer physics,thus resolving better air−sea and air−land interactions.
基金the Minerals Research Institute of Western Australia(M495)the computation resources provided by the Pawsey Supercomputing Centre with funding from the Australian Government and the Government of Western Australia.
文摘In 2012,the International Agency for Research on Cancer(IARC)classified diesel particulate matter(DPM)as a carcinogen to human.With the increased usage of diesel equipment in underground mines,miners have a high risk of over-exposure to DPM,which has drawn many concerns from the public.This study used computational fluid dynamics(CFD)to analyse the DPM dispersion and concentration distribution characteristics in an underground development face based on an onsite experiment.The DPM emitted from a moving loader under a forcing auxiliary ventilation system was simulated.The motion of the load-haul-dump(LHD)in the tunnel was represented by a dynamic mesh method.The species transport approach was applied to study the DPM behaviours.High DPM concentration zones were then identified based on the simulation results.The results could provide guidelines for work practices and be helpful to an optimum auxiliary ventilation design to reduce underground miner exposure.
基金National Key Research and Development Program,Grant/Award Number:2017YFB1104103Municipal Health Commission,Grant/Award Number:BJRITO-RDP-2023。
文摘Background:The ossification mechanism of the temporomandibular joint(TMJ)condyle remains unclear in human embryo.The size and structure of TMJ,shape of articular disc and the characteristics of omnivorous chewing in the pig are similar to those of humans.The pig is an ideal animal for studying the mechanism of ossification of the TMJ condyle during the embryonic period.Method:In a previous study by our group,it was found that there was no condylar ossification on embryonic day(E)45,but the ossification of condyle occurred between E75 and E90.In this study,a total of 12 miniature pig embryos on E45 and E85 were used.Six embryos were used for tissue sections(3 in each group).The remaining six embryos were used for transcriptomic and proteomic studies to find differential genes and proteins.The differentially expressed genes in transcriptome and proteomic analysis were verified by QPCR.Results:In total,1592 differential genes comprising 1086 up-regulated genes and 506 down-regulated genes were screened for fold changes of≥2 to≤0.5 between E45 and E85.In the total of 4613 proteins detected by proteomic analysis,there were 419 differential proteins including 313 up-regulated proteins and 106 down-regulated proteins screened for fold changes of≥2 to≤0.5 between E45 and E85.A total of 36 differential genes differing in both transcriptome and proteome analysis were found.QPCR analysis showed that 14 of 15 selected genes were consistent with transcriptome analysis.Conclusion:Condylar transcriptome and proteomic analysis during the development of TMJ in miniature pigs revealed the regulatory genes/proteins of condylar ossification.
基金Supported by the Special Fund Project of Provincial Financial Support for Agriculture of Shanxi Province(2017ZZCX-11)
文摘Four ground cover plant species of Taiyuan(Iris,Hemerocallis,Sedum,Hosta)were selected to study their capacities in adsorbing PM_(2.5).Meanwhile,the concentration of PM(2.5)in Taiyuan between April 2017 and August 2017 was recorded,and the characteristics of PM_(2.5)pollution in summer and autumn in Taiyuan were studied.The results showed that for the 4 plants,the ability to adsorb PM_(2.5)was in the order from great to small of Hosta,Iris,Hemerocallis,Sedum,in which H.plantaginea had the best effect to adsorb PM_(2.5).The fresh weight and dry weight per gram of H.plantaginea were 4.4 times and 2 times higher than those of S.spectabile,while the mass quality of dust adsorption was 2.8 times higher.The sorting result was the same as the ability to adsorb PM_(2.5)of unit leaf area.The result of the coefficient of purification showed that the purification coefficients of 3 vegetation structure were positive,and the combination of trees and shrubs in university campus had strong PM_(2.5)adsorption capacity.By comparing the seasonal variation of PM_(2.5)concentration in Taiyuan city,it found that the PM_(2.5)concentration was particularly high in late spring and early summer of Taiyuan,when most of the ground cover plants were not fully grown.Therefore,ground cover plants played an important role in the construction of landscape and the regulation of ecological environment in Taiyuan.
文摘The reliability of energy systems is strongly influenced by the prevailing climate conditions.With the increasing prevalence of renewable energy sources,the interdependence between energy and climate systems has become even stronger.This study examines the impact of different spatial resolutions in climate modeling on energy grid reliability assessment,with the Texas interconnection between 2033 and 2043 serving as a pilot case study.Our preliminary findings indicate that while low-resolution climate simulations can provide a rough estimate of system reliability,high-resolution simulations can provide more informative assessment of low-adequacy extreme events.Furthermore,both high-and low-resolution assessments suggest the need to prepare for severe blackout events in winter due to extremely low temperatures.
基金supported by the National Key Research and Development Program of China(2017YFC1404100,2017YFC1404104)the National Natural Science Foundation of China(41775100,41830964)+1 种基金the Shandong Province’s"Taishan"Scientist Project(2018012919)the collaborative project between the Ocean University of China(OUC),Texas A&M University(TAMU)and the National Center for Atmospheric Research(NCAR)and completed through the International Laboratory for High Resolution Earth System Prediction(iHESP)-a collaboration among QNLM,TAMU and NCAR。
文摘A regional coupled prediction system for the Asia-Pacific(AP-RCP)(38°E-180°,20°S-60°N) area has been established.The AP-RCP system consists of WRF-ROMS(Weather Research and Forecast,and Regional Ocean Model System) coupled models combined with local observational information through dynamically downscaling coupled data assimilation(CDA).The system generates 18-day forecasts for the atmosphere and ocean environment on a daily quasi-operational schedule at Pilot National Laboratory for Marine Science and Technology(Qingdao)(QNLM),consisting of 2 different-resolution coupled models:27 km WRF coupled with 9 km ROMS,9 km WRF coupled with 3 km ROMS,while a version of 3 km WRF coupled with 3 km ROMS is in a test mode.This study is a first step to evaluate the impact of high-resolution coupled model with dynamically downscaling CDA on the extended-range predictions,focusing on forecasts of typhoon onset,improved precipitation and typhoon intensity forecasts as well as simulation of the Kuroshio current variability associated with mesoscale oceanic activities.The results show that for realizing the extended-range predictability of atmospheric and oceanic environment characterized by statistics of mesoscale activities,a fine resolution coupled model resolving local mesoscale phenomena with balanced and coherent coupled initialization is a necessary first step.The next challenges include improving the planetary boundary physics and the representation of air-sea and air-land interactions to enable the model to resolve kilometer or sub-kilometer processes.
