A backbone enterprise under the ChinaAviation Industry Corporation,theSouth Aeronautic Power MachineryCompany is well known for its South brandmotorcycles.The SAPMC is the coreenterprise of the China South Aviation Po...A backbone enterprise under the ChinaAviation Industry Corporation,theSouth Aeronautic Power MachineryCompany is well known for its South brandmotorcycles.The SAPMC is the coreenterprise of the China South Aviation PowerMachinery Group,which is among China’sfirst 56 large-scale enterprise groups approvedby the State Council.In 1994,the展开更多
Traffic simulation can help to evaluate the impact of different mobility behaviors on the traffic flow from safety, efficiency, and environmental views. The objective of this paper is to extend the SUMO (Simulation of...Traffic simulation can help to evaluate the impact of different mobility behaviors on the traffic flow from safety, efficiency, and environmental views. The objective of this paper is to extend the SUMO (Simulation of Urban Mobility) road traffic simulator to model and evaluate the impact of motorcycles mobility on vehicular traffic. First, we go through diverse mobility aspects and models for motorcycles in SUMO. Later, we opt for the most suitable mobility models of motorcycles. Finally, the impact of motorcycle mobility on different kinds of vehicles is investigated in terms of environment, fuel consumption, velocity and travel time. The result of modeling and evaluation shows that based on the mobility model of the motorcycle, vehicular traffic flow can be enhanced or deteriorated.展开更多
Gasoline-powered motorcycles contribute disproportionately to traffic noise and emissions,so motorcycle electrification merits investigation.Recent advances in battery efficiency allow electric motorcycles(EMCs)to joi...Gasoline-powered motorcycles contribute disproportionately to traffic noise and emissions,so motorcycle electrification merits investigation.Recent advances in battery efficiency allow electric motorcycles(EMCs)to join electric cars and bicycles as a viable consumer option.This study quantifies noise and emissions using both simulations and experimental data,examines the factors that make motorcycles big offender and uses popular EMC makes and models to estimate the costs and benefits of electrification in the USA.Motorcycles produce more CO,CH4,NOx,HC and particulate matter per vehicle-mile travelled than passenger vehicles.Due to limited regulation of motorcycles and weak enforcement,the perceived noise level of motorcycles exceeds that of most other vehicles,being roughly double those of automobiles at speeds of over 30 mph and surpassing even those of medium trucks and buses at speeds of over 50 mph,at which point motorcycles exceeds the 80 dBA US standard limit.Electrification can resolve such issues,although range limitations and high prices are presently a barrier to widespread adoption.In order to realize these environmental benefits,it is important that electrification occurs with a corresponding shift away from coal as an energy source.Stricter emission regulations and stronger enforcement of existing prohibitions on certain forms of customization could also reduce the outlier status of gasoline-powered motorcycles.展开更多
Objectives: The primary objective was to characterize the range of Knowledge, Attitude, and Practice (KAP) of Helmet use in children amongst parents to prevent head injuries and death. Methods: This is a cross-section...Objectives: The primary objective was to characterize the range of Knowledge, Attitude, and Practice (KAP) of Helmet use in children amongst parents to prevent head injuries and death. Methods: This is a cross-sectional study, done by online survey using a snowball sampling technique, the number of included responses were 386 parents (Male and female) living in Riyadh Aged 21 - 60 years old or above. Results: The study showed that there is a difference in Parents’ belief in the importance of helmet use while riding a Bicycle vs Motorcycle/Quad bike and that was affected by parents’ education level, almost all the people who answered the survey (76.7%) agree that it is important for their children to wear a helmet when riding both a Bicycle and a Motorcycle or Quadbike with a cumulative percentage of (93.8%). And almost all agreed on multiple approaches to help increase helmet use be it by forcing rental shops to give out helmets, forcing sellers to recommend the use of helmets, increasing awareness campaigns, and imposing fines for not wearing helmets. Conclusions: This study is the first to explore Family helmet use while riding Bicycles and Motorcycles/Quad bikes. Although Parent’s belief in the importance of helmet use for their children was high, it is clear that the level of practice is low. With that the risk of head injuries might be high, our findings suggest that safety interventions for increasing pediatric helmet use are needed to increase helmet use and reduce the risk of head injury and hospitalization.展开更多
Roadside remote sensing measurement was used to explore the real-world emission status of light duty gasoline vehicles (LDGVs) and motorcycles in Macao. Both fuel-based and distance-based emission factors were deriv...Roadside remote sensing measurement was used to explore the real-world emission status of light duty gasoline vehicles (LDGVs) and motorcycles in Macao. Both fuel-based and distance-based emission factors were derived using the mass balance method. The emission concentration profile of LDGVs illustrated the benefits of tightening emission standards at the source country or region of import. The distance-based emission factors for CO, HC and NOx of LDGVs registered before 2000 were 8.00, 1.04 and 1.36 g/km, respectively. The distance-based emission factors for CO, HC and NOx of LDGVs registered in or after 2000 were 1.16, 0.15 and 0.18 g/km, respectively. The fuel-based CO emission factors of light duty motorcycles (LDMCs) and heavy duty motorcycles (HDMCs) registered before 2000 were about 10 times higher than those of LDGVs of the same age group. As the emissions of LDGVs decreased more quickly after 2000, the gap widens for newer vehicles. The distance-based HC emission factors of LDMCs and HDMCs registered before 2000 were 4.81 and 2.91 g/km, respectively. The distance-based HC emission factors of LDMCs and HDMCs registered in or after 2000 were 3.52 and 0.93 g/km, respectively. The poor emission performance of motorcycles and their larger share in the traffic flow will cause them to be the major contributor to traffic CO and HC emissions. LDMCs, especially two-stroke models, should be the priority for vehicle emission control efforts in Macao.展开更多
Monitoring of benzene, toluene and xylenes (BTEX) was conducted along with traffic counts at 17 roadside sites in urban areas of HoChiMinh. Toluene was the most abundant substance, followed by p,m-xylenes, benzene, ...Monitoring of benzene, toluene and xylenes (BTEX) was conducted along with traffic counts at 17 roadside sites in urban areas of HoChiMinh. Toluene was the most abundant substance, followed by p,m-xylenes, benzene, o-xylene and ethylbenzene. The maximum observed hour-average benzene concentration was 254 μg/m3 . Motorcycles contributed to 91% of the traffic fleet. High correlations among BTEX species, between BTEX concentrations and the volume of on-road motorcycles, and between inter-species ratios in air and in gasoline indicate the motorcycle-exhaust origin of BTEX species. Daily concentrations of benzene, toluene, ethylbenzene, p,m-xylenes and o-xylene were 56, 121, 21, 64 and 23 μg/m 3 , respectively. p,m-xylenes possess the highest ozone formation potential among the BTEX family.展开更多
The proliferation of Mobility on Demand (MOD) services has ushered in a surge of ridesharing platforms, catalyzing the emergence of micro mobility solutions like motorcycle sharing. Consequently, motorcycles have witn...The proliferation of Mobility on Demand (MOD) services has ushered in a surge of ridesharing platforms, catalyzing the emergence of micro mobility solutions like motorcycle sharing. Consequently, motorcycles have witnessed unprecedented growth over recent decades. This proliferation, while offering convenience, has introduced challenges such as diminished road capacity, and compromised safety. This study advocates for the implementation of exclusive motorcycle lanes to mitigate the ensuing disorderliness using VISSIM microsimulation platform. Empirical data from a key corridor in Dhaka is harnessed to calibrate and simulate network performance scenarios—pre- and post-implementation of dedicated motorcycle lanes. The outcomes of our simulation experiments exhibit the implementation of dedicated motorcycle lanes leads to a reduction in vehicular throughput but improvement the flow of motorcycles. In addition, Surrogate Safety Measures (SSMs) demonstrate the safety improvements through implementation of the treatment.展开更多
Scrotal trauma in motorcycle accidents (STMA) is a rare entity in the literature. In general, trauma to the genitals is not life-threatening. However, STMA can cause rupture of the testis with consequences that can le...Scrotal trauma in motorcycle accidents (STMA) is a rare entity in the literature. In general, trauma to the genitals is not life-threatening. However, STMA can cause rupture of the testis with consequences that can lead to alteration of sexuality and reproduction. We present an STMA case managed in a rural hospital where various types of injuries arise from motorcycle accidents. A 20-year-old man without any previous pathology presented in our hospital with a swollen painful scrotum. One week prior to presentation, the patient with a speeding motorbike drove over a speed bump, and the frame of his motorcycle broke into two halves, violently striking his genitals and causing scrotal trauma. After examination and investigation, patient has consented to scrotal exploration which was carried out. A partial left orchidectomy was performed and the right testicle was healthy. The evolution was favorable and the patient was discharged on the 5th postoperative day. Prognosis at 6 months was good. It is possible that genital trauma related to motorcycle accidents will become more frequent in the future. This underscores the importance of educating motorcyclists to respect the Highway Code;and making practitioners aware of the risk of serious injury in the event of acute scrotal trauma.展开更多
Motorcycle dependent cities have specific characteristics in terms of urban accessibility.A rapid increase in the number of motorcycles and other private motorized modes make transport problems more serious and cause ...Motorcycle dependent cities have specific characteristics in terms of urban accessibility.A rapid increase in the number of motorcycles and other private motorized modes make transport problems more serious and cause severe capacity problems for the infrastructure systems in these cities.Therefore,it is necessary to optimize the development of different modes to meet travel demand and to ensure accessibility in all urban areas.This paper aims to explore accessibility conditions in Ho Chi Minh City,a typical motorcycle dependent city in Vietnam.Understanding of accessibility could be the key element for urban planning in Ho Chi Minh City in particular and motorcycle dependent cities in general.Then,management measures for motorcycles and competitive modes will be proposed to improve the accessibility conditions and thus support sustainable urban transport development for motorcycle dependent cities.展开更多
Background: Road traffic injury remains a major source of blunt abdominal trauma (BAT). Road traffic injury and other forms of trauma have become a major health problem throughout the world especially in low and middl...Background: Road traffic injury remains a major source of blunt abdominal trauma (BAT). Road traffic injury and other forms of trauma have become a major health problem throughout the world especially in low and middle-income countries. In a previous study (2005-2007), abdominal trauma constituted 79 (4.8%) of trauma cases;BAT, 40 (53%) and penetrating abdominal trauma (PAT), 39 (47%). Effective policies on road safety should be developed based on local research and not on adapted models. We present this study to highlight the possible effect of legislation on the ban of the use of motorcycles on blunt abdominal trauma. Methods: Patients that presented to the University of Calabar Teaching Hospital, Calabar with BAT from 2008-2010 were prospectively studied based on a questionnaire following the legislation prohibiting the use of motorcycles. Results: A total of 12,083 patients presented during the study period, trauma patients totaled 4942 (41%), of this, 48 (1%) suffered abdominal trauma: BAT 19 (40%), penetrating abdominal trauma (PAT) 29 (60%). The age range of the patients was from 5 to 48 years (mean 26.6 years) with a M:F = 5.3:1. Road traffic accident (RTA) 17 (90%) [Motorvehicle 7 (37%), motorcycles 10 (53%)] was the commonest cause of trauma. The spleen was the commonest injured organ 14 (74%). Conclusion: Road traffic injury constitutes a public health challenge and the hallmark is prevention. Legislation prohibiting the use of motorcycles may have been responsible for the reduction in BAT.展开更多
Motorcycles transport commonly known as(Boda boda)in Tanzania has been growing up in the recently years in both urban and rural areas.Since motorcycles transport being authorized to carry passengers in the Tanzania it...Motorcycles transport commonly known as(Boda boda)in Tanzania has been growing up in the recently years in both urban and rural areas.Since motorcycles transport being authorized to carry passengers in the Tanzania it has been associated with many accidents resulting to large number of deaths and injuries in the country.Most of the Road Traffic Injuries victims are passengers,motorcyclists and pedestrians.Males are over represented in all causes.Most of the deceased were 18-29 years old.The major social-economic benefit of this study was to found out the main causes and measures of reducing the number of accidents associated with motorcycle transport service in both urban and rural areas.展开更多
The Pd-only catalysts for motorcycle were prepared by impregnating CeO2-ZrO2-Al2O3 and CeO2-ZrO2+Al2O3 with PdCl2 aqueous solution and characterized by X-ray diffraction (XRD), oxygen storage capacity (OSC) and H2-tem...The Pd-only catalysts for motorcycle were prepared by impregnating CeO2-ZrO2-Al2O3 and CeO2-ZrO2+Al2O3 with PdCl2 aqueous solution and characterized by X-ray diffraction (XRD), oxygen storage capacity (OSC) and H2-temperature-programmed reduction (H2-TPR) methods. The XRD result indicated that the CeO2-ZrO2-Al2O3 compound prepared by co-precipitation formed a single solid solution and had good thermal stability, and Pd phase was not observed in all catalysts. The TPR results showed that the reduction temperature of Pd/CeO2-ZrO2-Al2O3 catalyst was lower than that of Pd/CeO2-ZrO2+Al2O3 catalyst whether they were fresh or aged catalysts. The Pd/CeO2-ZrO2-Al2O3 exhibited high three-way catalytic activity at low temperature, high thermal stability, and wide working window, suggesting a great potential for applications.展开更多
Objective This study aimed to use an air-liquid interface(ALI)exposure system to simulate the inhalation exposure of motorcycle exhaust particulates(MEPs)and then investigate the benchmark dose(BMD)of MEPs by evaluati...Objective This study aimed to use an air-liquid interface(ALI)exposure system to simulate the inhalation exposure of motorcycle exhaust particulates(MEPs)and then investigate the benchmark dose(BMD)of MEPs by evaluating cell relative viability(CRV)in lung epithelial BEAS-2B cells.Methods The MEPs dose was characterized by measuring the number concentration(NC),surface area concentration(SAC),and mass concentration(MC).BEAS-2B cells were exposed to MEPs at different concentrations via ALI and CRV was determined using Cell Counting Kit(CCK-8)assay.BMD software was applied to calculate BMD and the lower limit of benchmark dose(BMDL)according to Akaike Information Coefficient(AIC),with P-value based on Hill,Linear,Polynomial,and Power model.Results Our results reveal that BMD of NC and SAC were estimated by the best-fitting Hill model,while MC was estimated by Polynomial model.The BMDL for CRV following ALI exposure to MEPs were as follows:364.2#/cm^(3)for NC;0.662×10^(7)nm^(2)/cm^(3)for SAC;and 0.278μg/m^(3)for MC.Conclusion These results indicate that MEPs exposure via ALI system induces a dose-dependent decrease of CRV and provides the potential exposure threshold of MEPs in a lung cell model.展开更多
文摘A backbone enterprise under the ChinaAviation Industry Corporation,theSouth Aeronautic Power MachineryCompany is well known for its South brandmotorcycles.The SAPMC is the coreenterprise of the China South Aviation PowerMachinery Group,which is among China’sfirst 56 large-scale enterprise groups approvedby the State Council.In 1994,the
文摘Traffic simulation can help to evaluate the impact of different mobility behaviors on the traffic flow from safety, efficiency, and environmental views. The objective of this paper is to extend the SUMO (Simulation of Urban Mobility) road traffic simulator to model and evaluate the impact of motorcycles mobility on vehicular traffic. First, we go through diverse mobility aspects and models for motorcycles in SUMO. Later, we opt for the most suitable mobility models of motorcycles. Finally, the impact of motorcycle mobility on different kinds of vehicles is investigated in terms of environment, fuel consumption, velocity and travel time. The result of modeling and evaluation shows that based on the mobility model of the motorcycle, vehicular traffic flow can be enhanced or deteriorated.
文摘Gasoline-powered motorcycles contribute disproportionately to traffic noise and emissions,so motorcycle electrification merits investigation.Recent advances in battery efficiency allow electric motorcycles(EMCs)to join electric cars and bicycles as a viable consumer option.This study quantifies noise and emissions using both simulations and experimental data,examines the factors that make motorcycles big offender and uses popular EMC makes and models to estimate the costs and benefits of electrification in the USA.Motorcycles produce more CO,CH4,NOx,HC and particulate matter per vehicle-mile travelled than passenger vehicles.Due to limited regulation of motorcycles and weak enforcement,the perceived noise level of motorcycles exceeds that of most other vehicles,being roughly double those of automobiles at speeds of over 30 mph and surpassing even those of medium trucks and buses at speeds of over 50 mph,at which point motorcycles exceeds the 80 dBA US standard limit.Electrification can resolve such issues,although range limitations and high prices are presently a barrier to widespread adoption.In order to realize these environmental benefits,it is important that electrification occurs with a corresponding shift away from coal as an energy source.Stricter emission regulations and stronger enforcement of existing prohibitions on certain forms of customization could also reduce the outlier status of gasoline-powered motorcycles.
文摘Objectives: The primary objective was to characterize the range of Knowledge, Attitude, and Practice (KAP) of Helmet use in children amongst parents to prevent head injuries and death. Methods: This is a cross-sectional study, done by online survey using a snowball sampling technique, the number of included responses were 386 parents (Male and female) living in Riyadh Aged 21 - 60 years old or above. Results: The study showed that there is a difference in Parents’ belief in the importance of helmet use while riding a Bicycle vs Motorcycle/Quad bike and that was affected by parents’ education level, almost all the people who answered the survey (76.7%) agree that it is important for their children to wear a helmet when riding both a Bicycle and a Motorcycle or Quadbike with a cumulative percentage of (93.8%). And almost all agreed on multiple approaches to help increase helmet use be it by forcing rental shops to give out helmets, forcing sellers to recommend the use of helmets, increasing awareness campaigns, and imposing fines for not wearing helmets. Conclusions: This study is the first to explore Family helmet use while riding Bicycles and Motorcycles/Quad bikes. Although Parent’s belief in the importance of helmet use for their children was high, it is clear that the level of practice is low. With that the risk of head injuries might be high, our findings suggest that safety interventions for increasing pediatric helmet use are needed to increase helmet use and reduce the risk of head injury and hospitalization.
基金supported by the Macao Environmental Protection Bureau
文摘Roadside remote sensing measurement was used to explore the real-world emission status of light duty gasoline vehicles (LDGVs) and motorcycles in Macao. Both fuel-based and distance-based emission factors were derived using the mass balance method. The emission concentration profile of LDGVs illustrated the benefits of tightening emission standards at the source country or region of import. The distance-based emission factors for CO, HC and NOx of LDGVs registered before 2000 were 8.00, 1.04 and 1.36 g/km, respectively. The distance-based emission factors for CO, HC and NOx of LDGVs registered in or after 2000 were 1.16, 0.15 and 0.18 g/km, respectively. The fuel-based CO emission factors of light duty motorcycles (LDMCs) and heavy duty motorcycles (HDMCs) registered before 2000 were about 10 times higher than those of LDGVs of the same age group. As the emissions of LDGVs decreased more quickly after 2000, the gap widens for newer vehicles. The distance-based HC emission factors of LDMCs and HDMCs registered before 2000 were 4.81 and 2.91 g/km, respectively. The distance-based HC emission factors of LDMCs and HDMCs registered in or after 2000 were 3.52 and 0.93 g/km, respectively. The poor emission performance of motorcycles and their larger share in the traffic flow will cause them to be the major contributor to traffic CO and HC emissions. LDMCs, especially two-stroke models, should be the priority for vehicle emission control efforts in Macao.
基金supported by Vietnam National University, HoChiMinh City and Vietnam National Foundation for Development of Science and Technology
文摘Monitoring of benzene, toluene and xylenes (BTEX) was conducted along with traffic counts at 17 roadside sites in urban areas of HoChiMinh. Toluene was the most abundant substance, followed by p,m-xylenes, benzene, o-xylene and ethylbenzene. The maximum observed hour-average benzene concentration was 254 μg/m3 . Motorcycles contributed to 91% of the traffic fleet. High correlations among BTEX species, between BTEX concentrations and the volume of on-road motorcycles, and between inter-species ratios in air and in gasoline indicate the motorcycle-exhaust origin of BTEX species. Daily concentrations of benzene, toluene, ethylbenzene, p,m-xylenes and o-xylene were 56, 121, 21, 64 and 23 μg/m 3 , respectively. p,m-xylenes possess the highest ozone formation potential among the BTEX family.
文摘The proliferation of Mobility on Demand (MOD) services has ushered in a surge of ridesharing platforms, catalyzing the emergence of micro mobility solutions like motorcycle sharing. Consequently, motorcycles have witnessed unprecedented growth over recent decades. This proliferation, while offering convenience, has introduced challenges such as diminished road capacity, and compromised safety. This study advocates for the implementation of exclusive motorcycle lanes to mitigate the ensuing disorderliness using VISSIM microsimulation platform. Empirical data from a key corridor in Dhaka is harnessed to calibrate and simulate network performance scenarios—pre- and post-implementation of dedicated motorcycle lanes. The outcomes of our simulation experiments exhibit the implementation of dedicated motorcycle lanes leads to a reduction in vehicular throughput but improvement the flow of motorcycles. In addition, Surrogate Safety Measures (SSMs) demonstrate the safety improvements through implementation of the treatment.
文摘Scrotal trauma in motorcycle accidents (STMA) is a rare entity in the literature. In general, trauma to the genitals is not life-threatening. However, STMA can cause rupture of the testis with consequences that can lead to alteration of sexuality and reproduction. We present an STMA case managed in a rural hospital where various types of injuries arise from motorcycle accidents. A 20-year-old man without any previous pathology presented in our hospital with a swollen painful scrotum. One week prior to presentation, the patient with a speeding motorbike drove over a speed bump, and the frame of his motorcycle broke into two halves, violently striking his genitals and causing scrotal trauma. After examination and investigation, patient has consented to scrotal exploration which was carried out. A partial left orchidectomy was performed and the right testicle was healthy. The evolution was favorable and the patient was discharged on the 5th postoperative day. Prognosis at 6 months was good. It is possible that genital trauma related to motorcycle accidents will become more frequent in the future. This underscores the importance of educating motorcyclists to respect the Highway Code;and making practitioners aware of the risk of serious injury in the event of acute scrotal trauma.
文摘Motorcycle dependent cities have specific characteristics in terms of urban accessibility.A rapid increase in the number of motorcycles and other private motorized modes make transport problems more serious and cause severe capacity problems for the infrastructure systems in these cities.Therefore,it is necessary to optimize the development of different modes to meet travel demand and to ensure accessibility in all urban areas.This paper aims to explore accessibility conditions in Ho Chi Minh City,a typical motorcycle dependent city in Vietnam.Understanding of accessibility could be the key element for urban planning in Ho Chi Minh City in particular and motorcycle dependent cities in general.Then,management measures for motorcycles and competitive modes will be proposed to improve the accessibility conditions and thus support sustainable urban transport development for motorcycle dependent cities.
文摘Background: Road traffic injury remains a major source of blunt abdominal trauma (BAT). Road traffic injury and other forms of trauma have become a major health problem throughout the world especially in low and middle-income countries. In a previous study (2005-2007), abdominal trauma constituted 79 (4.8%) of trauma cases;BAT, 40 (53%) and penetrating abdominal trauma (PAT), 39 (47%). Effective policies on road safety should be developed based on local research and not on adapted models. We present this study to highlight the possible effect of legislation on the ban of the use of motorcycles on blunt abdominal trauma. Methods: Patients that presented to the University of Calabar Teaching Hospital, Calabar with BAT from 2008-2010 were prospectively studied based on a questionnaire following the legislation prohibiting the use of motorcycles. Results: A total of 12,083 patients presented during the study period, trauma patients totaled 4942 (41%), of this, 48 (1%) suffered abdominal trauma: BAT 19 (40%), penetrating abdominal trauma (PAT) 29 (60%). The age range of the patients was from 5 to 48 years (mean 26.6 years) with a M:F = 5.3:1. Road traffic accident (RTA) 17 (90%) [Motorvehicle 7 (37%), motorcycles 10 (53%)] was the commonest cause of trauma. The spleen was the commonest injured organ 14 (74%). Conclusion: Road traffic injury constitutes a public health challenge and the hallmark is prevention. Legislation prohibiting the use of motorcycles may have been responsible for the reduction in BAT.
文摘Motorcycles transport commonly known as(Boda boda)in Tanzania has been growing up in the recently years in both urban and rural areas.Since motorcycles transport being authorized to carry passengers in the Tanzania it has been associated with many accidents resulting to large number of deaths and injuries in the country.Most of the Road Traffic Injuries victims are passengers,motorcyclists and pedestrians.Males are over represented in all causes.Most of the deceased were 18-29 years old.The major social-economic benefit of this study was to found out the main causes and measures of reducing the number of accidents associated with motorcycle transport service in both urban and rural areas.
基金Project supported by the National High Technology Research and Development Program of China (863 Program,2006AA06Z347)the Specialized Research Fund for the Doctoral Program of Higher Education (20070610026)
文摘The Pd-only catalysts for motorcycle were prepared by impregnating CeO2-ZrO2-Al2O3 and CeO2-ZrO2+Al2O3 with PdCl2 aqueous solution and characterized by X-ray diffraction (XRD), oxygen storage capacity (OSC) and H2-temperature-programmed reduction (H2-TPR) methods. The XRD result indicated that the CeO2-ZrO2-Al2O3 compound prepared by co-precipitation formed a single solid solution and had good thermal stability, and Pd phase was not observed in all catalysts. The TPR results showed that the reduction temperature of Pd/CeO2-ZrO2-Al2O3 catalyst was lower than that of Pd/CeO2-ZrO2+Al2O3 catalyst whether they were fresh or aged catalysts. The Pd/CeO2-ZrO2-Al2O3 exhibited high three-way catalytic activity at low temperature, high thermal stability, and wide working window, suggesting a great potential for applications.
基金supported by the funding from the National Natural Science Foundation of China[No.81472955,82073596 and 91643203]。
文摘Objective This study aimed to use an air-liquid interface(ALI)exposure system to simulate the inhalation exposure of motorcycle exhaust particulates(MEPs)and then investigate the benchmark dose(BMD)of MEPs by evaluating cell relative viability(CRV)in lung epithelial BEAS-2B cells.Methods The MEPs dose was characterized by measuring the number concentration(NC),surface area concentration(SAC),and mass concentration(MC).BEAS-2B cells were exposed to MEPs at different concentrations via ALI and CRV was determined using Cell Counting Kit(CCK-8)assay.BMD software was applied to calculate BMD and the lower limit of benchmark dose(BMDL)according to Akaike Information Coefficient(AIC),with P-value based on Hill,Linear,Polynomial,and Power model.Results Our results reveal that BMD of NC and SAC were estimated by the best-fitting Hill model,while MC was estimated by Polynomial model.The BMDL for CRV following ALI exposure to MEPs were as follows:364.2#/cm^(3)for NC;0.662×10^(7)nm^(2)/cm^(3)for SAC;and 0.278μg/m^(3)for MC.Conclusion These results indicate that MEPs exposure via ALI system induces a dose-dependent decrease of CRV and provides the potential exposure threshold of MEPs in a lung cell model.