检索结果-南通市图书馆

Influence of biomass burning on ozone levels in the Megalopolis of Central Mexico during the COVID-19 lockdown

Journal of Environmental Sciences 2024年第9期143卷 99-115页

作者： Victor Almanza Luis Gerardo Ruiz-Suárez Ricardo Torres-Jardón Agustín García-Reynoso Iván Y.Hernández-Paniagua Institute for Atmospheric Sciences and Climate Change National Autonomous University of MexicoCoyoacan 04510Mexico CityMexico

The massive reductions in anthropogenic emissions resulting from the COVID-19 lockdown provided a unique opportunity to evaluate the effect of mitigation measures aiming to abate air pollution.In Mexico,the total lockdown period took place during the dry-hot season when biomass burning activity is enhanced.Here,we investigate the role of biomass burning emissions on regional ozone levels in the Megalopolis of Central Mexico.The studied period covers the lockdown phases 2 and 3,and the first month of the New Normal.We applied a factor separation technique and process analysis to estimate the pure and synergistic contributions of emission reductions under lockdown and that from biomass burning to daily ozone maximum concentrations in 7 metropolitan areas of different states in the Megalopolis.The results revealed that biomass burning plumes likely masked the effect of massive reductions from mobile emissions,impacted the PBL development during phase 3 and favored transition and mixed NO_(x)-limited and VOC-limited regional regimes.This contributed to increased ozone production in the middle to lower PBL by changing the regional background levels which potentially could bias high ozone production efficiency estimations.Given the Megalopolis contribution to economic and societal development at national scale,our study suggests that ozone mitigation measures during the dry-hot season targeting mainly mobile emissions will likely be offset by biomass burning plumes.A regional and synergic policy aiming to control biomass burning would help to reduce the occurrence of high ozone levels in Central Mexico with the co-benefit of tackling short-lived climate pollutants.

关键词： COVID-19 Mexico Megalopolis Ozone Factor Separation process analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

analysis of the Flow Field Characteristics Associated with the Dynamic Rock Breaking process Induced by a Multi-Hole Combined External Rotary Bit

引用

Fluid Dynamics & Materials processing 2021年第4期17卷 697-710页

作者： Quanbin Ba Yanbao Liu Zhigang Zhang Wei Xiong Kai Shen State key Laboratory of Gas Disaster Monitoring and Emergency Technology Chongqing400037China CCTEG Chongqing Research Institute Chongqing400037China

The characteristics of the flow field associated with a multi-hole combined external rotary bit have been studied by means of numerical simulation in the framework of an RNG k-εturbulence model,and compared with the results of dedicated rock breaking drilling experiments.The numerical results show that the nozzle velocity and dynamic pressure of the nozzle decrease with an increase in the jet distance,and the axial velocity of the nozzle decays regularly with an increase in the dimensionless jet distance.Moreover,the axial velocity related to the nozzle with inclination angle 20°and 30°can produce a higher hole depth,while the radial velocity of the nozzle with 60°inclination can enlarge the hole diameter.The outcomes of the CFD simulations are consistent with the actual dynamic rock breaking and pore forming process,which lends credence to the present results and indicates that they could be used as a reference for the future optimization of systems based on the multi-hole combined external rotary bit technology.

关键词： External rotation nozzle RNG k-εturbulence model flow field characteristics rock breaking and hole forming process analysis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Study on Application of process analysis in Mechanical processing Industry

Study on Application of Process Analysis in Mechanical Proce...

引用

2012 3rd International Conference on Information Technology for Manufacturing Systems(ITMS 2012)

作者： Huang Zong xiang Li Baoping Li Chunguang Zhongyuan University of Technology China Machinery TDI International Engineering CO. LTD

This paper primarily makes an analysis and study on existing production processes adopted in production lines of mechanical processing industry, and adopts methods of process analysis and work analysis, principles of "ECRS", 5W1 H questioning and improvement analysis sheets and relevant techniques to perform detailed analysis on the existing production processes in respect of complicated process settings, unreasonable processes and other problems in processes of production.According to field observations and data collected, measures are proposed to solve such problems like low efficiency in material flows, waiting of parts, long hauling distance etc.and process improvement plans are made on basis of facilitating reasonable material flows and benefits maximization.The results of analyses and appraisals on new plans show the efficiency of production processes has been improved effectively, which will make it possible that enterprises reduce costs and enhance their competitiveness further.

关键词： Production line process analysis process improvement work analysis

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

analysis of a Cold Wave Weather process in Chengdu in March 2010

引用

Meteorological and Environmental Research 2011年第6期2卷 1-5,10页

作者： LI Xin-yi XIE Na SHI Juan LI Yu AN Xia Chengdu Meteorological Bureau in Sichuan Province Chengdu 610071China

[Objective] The aim was to analyze one cold wave weather process in Chengdu in March in 2010.[Method] Based on the NCEP 1°×1° 6 h interval reanalysis data and daily observation data,using synoptic analysis and diagnosis methods,and combining with the cold wave forecast index in spring of Sichuan,a cold wave event covering the whole region between March 21 and 24,2010 was analyzed from the aspects of circulation background,influencing weather systems and weather causation.[Result] Results showed that the 500 high-altitude cold vortex,700-850 hPa low layer shear,and ground cold front were the main systems that influenced this cold wave;there was a ridge from Lake Balkhash across Lake Baikal at 500 hPa.The early stage of the process was controlled by the high pressure ridge and the temperature was increasing obviously.The daily mean temperature was high.The range of cold high pressure was large and the central intensity was 1 043.0 hPa;the cold air was strong and deep which was in accordance with the strong surface temperature reduction center.The strong north airstream of Lake Balkhash to Lake Baikal,ground cold high pressure center intensity changes,north and south ocean pressure and temperature differences,850 hPa temperature changes,cold advection movement route and intensity were considered as reference factors for the forecast of cold wave intensity.[Conclusion] The study provided theoretical basis for improving the forecast ability of cold wave weather.

关键词： Cold wave Circulation situation Forecast focus process analysis Chengdu China

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

analysis on "96. 8" Heavy Rainstorm process in Handan

引用

Meteorological and Environmental Research 2012年第8期3卷 18-23页

作者： ZHANG Yan-li YANG Xue-chuan WANG Ga SONG Xiao-hui TIAN Xiu-xia Shexian Meteorological Bureau in Hebei Province Shexian 056400China Handan Meteorological Bureau in Hebei Province Handan 056001China

[ ObjEtive] The research aimed to analyze ＂96.8＂ heavy rainstorm process causing flood disaster in Handan. [ Method] Based on ac- tual situation data, satellite cloud data and NCEP reanalysis data in the first dekad of August in 1996, ＂96.8＂ heavy rainstorm process causing flood disaster in Handan was analyzed to understand occurrence reason of the flood disaster. [ Result] Two meso-scale convective cloud clusters which developed and went north in turn caused ＂96.8＂ heavy rainstorm in Handan. Typhoon and inverted trough were main weather systems induced flood disaster in Handan. In going north process of the low-level jet, due to blocking of the subtropical high, water vapor and energy accumulated in Handan, providing material basis for formation of the heavy rainstorm. Development and eastward movement of the short-wave trough at middle lati- tude and continuous invasion of the reflux weak cold air at the low layer were direct reason for triggering generation and development of the convec- tive cloud cluster, and further causing continuous rainstorm. Wet layer over the rainstorm zone was deep and thick. Meridional distribution of the wet zone was wider than latitudinal distribution. South China Sea and Bay of Bengal were water vapor sources for the rainstorm zone. In the whole rain- storm period, it was convergence at low layer and divergence at high layer in the rainstorm zone. It was positive vorticity at low layer and negative vorticity at high layer. Precipitation intensity changed as convergence and divergence. Rainstorm zone had strong ascending motion. As strengthe- ning and uplifting of the ascending motion strong center, strong precipitation also strengthened. Rainstorm center was near the biggest vertical ve- locity center. Strong precipitation changed as vertical ascending motion. [ Conclmion] The research provided scientific basis for disaster prevention and reduction and decision-making service.

关键词： Heavy rainstorm No. 9608 strong typhoon process analysis Handan China

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

analysis of Heavy Rain process in South Liaoning Province Caused by No. 1105 Tropical Storm "Meari"

引用

Meteorological and Environmental Research 2012年第8期3卷 7-10,15页

作者： LIU Tong-yi YAO Wen ZHANG Jing ZHAO Xiao-chuan SUN Yao Yingkou Meteorological Bureau in Liaoning Province Yingkou 115000China

[ Objective] The aim was to study the heavy rainstorm by tropical storm ＂Meari＂ in Liaoning. [ Method] Based on the ground data, radar data, numerical report data, encrypted automatic station and NCEP reanalysis data, the heavy rain process by tropical storm ＂ Meari＂ was ana- lyzed. The changes of each physical quantity were discussed while the tropical storm moving northward. [ Result] The subtropical high pressure and Mainland high pressure jointed and maintained, forced ＂ Meari＂ turned northwest. The low-level southeast jet by ＂Meari＂ provided full water trans- mission and layer unstable conditions. The heavy rain mainly distributed in the tongue area of high energy, and the total energy was a key index to predict the rainfall area. [ Condusion] The study provided reference for the report business.

关键词： Tropical storm Meari Heavy rainfall process analysis Liaoning China

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

analysis of a Rare Continuous Rainy process in Midsummer

引用

Meteorological and Environmental Research 2011年第8期2卷 26-29页

作者： MA Ling CHEN Ling-ling WANG Xiang Bengbu Meteorological Bureau in Anhui Province Bengbu 233000China

[Objective] The research aimed to analyze a rare low temperature and rainy weather process which happened in Anhui Province from July 22 to August 14,2009.[Method] Based on the data of conventional observation,NCEP analysis field and automatic station,a rare low temperature and rainy weather process which occurred in Anhui Province from July 22 to August 14,2009 was analyzed.The formation reason of continuous rainy process in midsummer was discussed.The circulation characteristics and influence systems of continuous rainy process were revealed.On the base,the influences of configuration of circulation fields and difference of physical quantity fields at high and low layers on range and intensity of precipitation were analyzed.[Result] According to the circulation situation and influence system,the continuous rainy process could be divided into four stages:July 22-24,from July 27 to August 1,August 4-8 and August 9-14.Moreover,it was respectively affected by northeast low vortex,cold and warm air,high-level low trough,typhoon and periphery of subtropical high at four stages.The maintenance of big specific humidity zone provided sufficient water vapor condition for the continuous rainy weather.The rainstorm appeared in dense zone of specific humidity line,where the specific humidity >13 g/kg in the humidity front zone.A temperature trough maintained at 850 hPa.The cold air which continued to diffuse and go south was main reason of the abnormally low temperature during the continuous rainy period.Moreover,it provided ascending motion condition for precipitation maintenance.[Conclusion] The research provided references for actual forecast of continuous rainy weather.

关键词： Continuous rainy weather Midsummer Circulation characteristics Physical quantity field process analysis China

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

analysis on a Severe Convective Weather process in Summer in Beihai

引用

Meteorological and Environmental Research 2011年第2期2卷 46-49,52页

作者： CHEN Qiu-ji LIANG Bao-rong YIN Hai-yan Beihai Meteorological Bureau in Guangxi Beihai 536000China

[Objective] The research aimed to analyze a strong convective weather process in Beihai in summer. [Method] By using Micaps conventional data and the single station site information of Beihai, radar data, a strong convective weather process in Beihai City in August, 2010 was analyzed. [Result] 850 and 700 hPa cyclonic low-pressure circulation in the north of Vietnam and Beibu Gulf coast was favorable for the transportation of Bengal Bay southwest airflow, which provided the sufficient water vapor condition for the strong precipitation. The interaction of weak cold air and southeast warm wet airflow was the main cause of the strong rainfall process. The falling zone of strong precipitation related to the water vapor convergence. The maintenance of water vapor flux divergence field in southeast-northwest direction was favorable for the duration of strong precipitation in the south of Guangxi. Before the strong precipitation, the positive and negative vorticity in the high and low levels in Beihai station both abruptly strengthened, which was very favorable for generating the convection. The vertical velocity in the strong precipitation process turned from the positive value at the beginning into the negative value as the height variation. The turning had the indicated and early-warning roles on the generation of strong convective weather. [Conclusion] The research provided the theory basis for the strong convective weather forecast in Guangxi coast in summer.

关键词： Strong convection Weak cold air process analysis Beihai City China

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

analysis on the Heavy Snow Weather process in Benxi Area

引用

Meteorological and Environmental Research 2011年第1期2卷 24-27页

作者： KOU Si-cong CAO Wen Benxi Meteorological Observatory Liaoning ProvinceBenxi 117000China Nanjing University of Information Science and Technology Nanjing 210044China

[Objective] The aim was to study the formation and development of a heavy snow in Benxi area. [Method] Based on conventional meteorological data, the formation and development of a heavy snow in Benxi area from December 4th to 5th in 2009 were analyzed from the aspects of weather situation evolution and physical quantity field feature. [Result] The heavy snow was caused by upper trough and North China cyclone. In this process, there was upper level divergence and lower level convergence over Benxi area, and it was warm at low attitude and cold at high attitude; southwest jet at low attitude transported water vapor from Bohai Sea to eastern Liaoning, which provided good water vapor condition for snow, but it didn’t reach heavy snow due to inadequate ascending force. The development of Ural Mountains high ridge played an important role in the snow process and the strengthened high ridge moving northward was beneficial to the southward movement of cold air and deepening of upper trough. analysis on physical quantity field could provide reference for predicting beginning and ending time and strength of heavy snow. [Conclusion] The study could provide basis for the forecast of heavy snow.

关键词： Heavy snow Weather situation Physical quantity process analysis Benxi area China

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The Camshaft Timing Gear Forming process analysis and Die Design

The Camshaft Timing Gear Forming Process Analysis and Die De...

引用

2018中国汽车工程学会年会

作者： GU WenJin SUN Lichen Liaoning Xingcheng Powder Metallurgy Co. LTD

this article through to the analysis of the camshaft timing gear product figure,combining with the characteristics of powder metallurgy parts forming and the production technology of the camshaft timing gear is determined.According to the experience of the previous camshaft timing gear production,optimization design,a set of pressing mould overcomes the camshaft timing gear easy to crack during forming,the difficult problems of demoulding,to run the production.

关键词： powder metallurgy process analysis pressing mould mould taper the die structure

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：