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Multiple grain-size fraction analysis of heavy minerals and the provenance identification of sediments from the abandoned Huanghe River,eastern China
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作者 Mengyao WANG Bingfu JIN Jianjun JIA 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2023年第3期921-935,共15页
The quantitative analysis of sediment sources in a sink is an important scientific topic and challenge in provenance research.The characteristics of heavy minerals,combined with the geochemical constituents of detrita... The quantitative analysis of sediment sources in a sink is an important scientific topic and challenge in provenance research.The characteristics of heavy minerals,combined with the geochemical constituents of detrital grains,provide a reliable provenance-tracing approach.We developed a mineral identification method to analyze the multiple grain-size fraction of sediments,from which the elemental geochemistry of hornblende was used to compare the characteristics of sediments from the Huaihe River and Huanghe(Yellow)River in eastern China.Elements that were statistically identified as being able to discriminate sediment provenance were employed to perform a quantitative analysis of the sources of sediments of the abandoned Huanghe River.Results reveal that the Huaihe River is characterized by a high amphibole content of>60%and that the Huanghe and abandoned Huanghe rivers have greater abundances of limonite and carbonate minerals compared with those of the Huaihe River.The contents of trace elements and rare earth elements in hornblende show that the sediments of the abandoned Huanghe River are similar to those of the Huanghe River but different from those of the Huaihe River.Furthermore,chemical mass balance was used to calculate the relative contributions of different provenances of sediment from the abandoned Huanghe River,and nine trace elements of hornblende were identified as discriminators of provenance.Approximately 2%of the hornblende in the abandoned Huanghe River is derived from the Huaihe River and 98%from the Huanghe River.Considering the proportion of hornblende in the total sediment,it is inferred that the contribution of Huaihe River sediment to the abandoned Huanghe River is approximately 0.5%.This study shows that mineral analysis using multiple grain-size fractions(within the wide range of 1Φto 6Φ)with assessment in elemental geochemistry of hornblende can characterize the provenance of fluvial material in coastal zones. 展开更多
关键词 quantitative provenance analysis heavy mineral multiple grain-size fraction HORNBLENDE elemental geochemistry fluvial sediment the abandoned Huanghe River
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Analysis of Investigation on Ebian Spotted Cattle and Suggestions
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作者 Zhaohua LI Yi SHI +7 位作者 Fang HE Min CHEN Jun YI Jia GAN Donghui FANG Yueda AGUO Xiaodong DENG Wei WANG 《Agricultural Biotechnology》 CAS 2023年第3期58-60,共3页
Ebian spotted cattle has the ability to adapt to the local natural ecological environment,and is one of the excellent local cattle breeds in Sichuan.Ebian spotted cattle is a breed of cattle for both service and meat ... Ebian spotted cattle has the ability to adapt to the local natural ecological environment,and is one of the excellent local cattle breeds in Sichuan.Ebian spotted cattle is a breed of cattle for both service and meat use and formed through long-term natural selection and artificial selection.Because of the weak development and utilization of this breed,the economic benefits of excellent breeds have not been fully brought into play,and farmers'enthusiasm in breeding is poor,so that the number of Ebian spotted cattle has reduced year by year.In order to strengthen the protection,development and utilization of Ebian spotted cattle as a local excellent breed,combined with the third national survey of livestock and poultry genetic resources in 2021,Ebian spotted cattle was investigated,and a comprehensive,scientific and objective analysis of its population numbers was conducted.Besides,reasonable suggestions were put forward. 展开更多
关键词 Ebian Ebian spotted cattle Local fine varieties quantity analysis Suggestions
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The Quantitative Analysis of Land Use Structure Characteristics of County in Mountainous Areas in Sichuan Province of China——A Case Study of Rong County 被引量:6
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作者 ZHOU Wei1,2,WANG Chen1,2,SONG Xing1,2,DENG Liang-ji1,2 1.College of Resource and Environment,Sichuan Agricultural University,Ya’an 625014,China 2.Key Laboratory of Land Information in Sichuan Province,Ya’an 625014,China 《Asian Agricultural Research》 2011年第5期28-33,共6页
Based on the data concerning detailed survey on land in the year 2009 and land change in the year 2010 in Rong County,a mountainous region of Sichuan Province,by using quantitative geographical model,we conduct quanti... Based on the data concerning detailed survey on land in the year 2009 and land change in the year 2010 in Rong County,a mountainous region of Sichuan Province,by using quantitative geographical model,we conduct quantitative analysis of the status quo of land use in Rong County in terms of land use diversification,land use centralization,land use combination type,land use geographic significance and comprehensive use degree of land use.The results show some characteristics as follows.Firstly,land use in study area displays prominent characteristic of diversification;there is a high degree of completeness land use type;there is a great similarity among towns.Secondly,there is limited combination number of land use type;mostly the combination number of the towns is 2-3;the holistic function of regional land is fragile;the proportion of farmland areas is big,reaching 40.09%;the land use type of 21 towns is farmland.Thirdly,the towns with prominent characteristic of diversification of land use in Rong County,have low degree of centralization of land use and relatively big combination number of land use type,and vice versa.Fourthly,the type and quantity of agricultural land resources with geographical significance are relatively complete with nothing missing;it abounds in untapped land,but the overall index values of land use are all smaller than 300,with low overall use degree of land. 展开更多
关键词 LAND USE quantity structure QUANTITATIVE analysis
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Sediment transport in the Luanhe River delta:grain size trend analysis 被引量:3
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作者 YU Xiaoxiao LI Tiegang +7 位作者 GU Dongqi FENG Aiping LIU Shihao LI Ping XU Guoqiang YAN Wenwen ZHANG Zhiwei ZHU Zhengtao 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2019年第3期982-997,共16页
Sediment grain size in the deltaic environment of the Luanhe River(LR),Liaoning,China,contains sediment transport pathway information useful in elucidating the shoreline change and fluvialmarine interaction.In this st... Sediment grain size in the deltaic environment of the Luanhe River(LR),Liaoning,China,contains sediment transport pathway information useful in elucidating the shoreline change and fluvialmarine interaction.In this study,we utilized numerical partitioning of the sedimentary components and geostatistical grain size trend analysis(GSTA)to define the sediment transport pattern in the Luanhe River delta(LRD)and interpolated the sediment transport pattern using content changes of end numbers(EM).EM1(the mean grain size 7.12Ф,fine silt),EM2(2.37Ф,fine sand),and EM3(1.27Ф,medium sand)components were identified by the numerical partitioning by GSTA.Kriging interpolation method was used to interpolate the parameters of the grain size for the regular grid,and the interpolation radius was 0.015 decimal degree.We chose 0.09 decimal degree as the characteristic distance for GSTA in the semivariogram model using the geostatistical method.The FB(-)case(finer,better sorted and more negatively skewed)was adopted in GSTA for its satisfaction in the Global Moran’s I test.The result of the GSTA shows that the sediments in the south barriers(SBs)were transported to the southwest of the study area.The sediments in the north,in the SE direction of sediment transport trend from the river mouth,indicated that the sediments in the north of the study area were transported from the LR to the northern beaches,and to the south and east of the study area.The sediment transport trend that simplified by GSTA as the FB(-)case was approved by the content changes of sedimentary components(i.e.EM1,EM2,and EM3).In addition,the turbulent jet diffusion pattern indicated that the coarse sediments(EM3)were delivered by LR during the flood season,and the EM2 and EM1 were from wave and tide,respectively. 展开更多
关键词 Luanhe River DELTA SEDIMENT transport grain-size partitioning geostatistical GRAIN size TREND analysis(GSTA)
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Analysis on the Heavy Snow Weather Process in Benxi Area 被引量:1
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作者 KOU Si-cong CAO Wen 《Meteorological and Environmental Research》 CAS 2011年第1期24-27,共4页
[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 Decemb... [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. 展开更多
关键词 Heavy snow Weather situation Physical quantity Process analysis Benxi area China
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Analysis of a Rare Continuous Rainy Process in Midsummer 被引量:1
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作者 MA Ling CHEN Ling-ling WANG Xiang 《Meteorological and Environmental Research》 CAS 2011年第8期26-29,共4页
[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 an... [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. 展开更多
关键词 Continuous rainy weather MIDSUMMER Circulation characteristics Physical quantity field Process analysis China
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Diagnostic Analysis of a Snowfall Weather in Beijing,Tianjin and Hebei in 2010 被引量:2
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作者 ZHOU He-ling CHEN Min 《Meteorological and Environmental Research》 2012年第1期32-35,40,共5页
[ Objective] The research aimed to analyze a local snowstorm weather process which happened in Beijing, Tianjin and Hebei during I - 4 January, 2010. [ Method] Based on routine meteorological observation data and NCEP... [ Objective] The research aimed to analyze a local snowstorm weather process which happened in Beijing, Tianjin and Hebei during I - 4 January, 2010. [ Method] Based on routine meteorological observation data and NCEP/NCAR 2.5° ×2.5° grid data (four times every day), a lo- cal snowstorm weather process which happened in Beijing, Tianjin and Hebei during 1 -4 January, 2010 was carried out diagnostic analysis by using composite analysis method. [Result] Circumfluence on the ground and strong cold advection in the rear of upper trough were the main weath- er system of the snowfall. The deep thick wet layer and strong water vapor convergence provided sufficient water vapor for snowfall. The divergence field of low-level convergence and high^level divergence, dynamic coupling effect of vorticity provided favorable dynamic condition upwardly for the occurrence of strong snowfall. The steep dense area of Oso, low temperature at the ground layer and inversion temperature at the high layer provided certain energy condition for the development of snowfall weather. [ Conclusion] The research provided theoretical basis for snowfall forecast in future. 展开更多
关键词 SNOWFALL Physical quantity Diagnostic analysis Beijing Tianjin and Hebei China
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Grain-size distribution characteristics of red sandy sediments in Dongjiang River valley,southern Nanling Mountains,during the MIS2 stage 被引量:1
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作者 ShuHuan Du 1,BaoSheng Li 1,2,DongFeng Niu 1,XiaoHao Wen 1,FengNian Wang 1,XianJiao Ou 1,Yi Yang 1,YueJun Si 1,XinNan Zhao 1 1.Department of Geography,South China Normal University,Guangzhou,Guangdong 510631,China 2.State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an,Shaanxi 710061,China 《Research in Cold and Arid Regions》 2009年第5期443-447,共5页
Layer LJ3 of Linjiang stratigraphic section in Dongjiang River valley in the south of the Nanling Mountains is a set of red sandy sediments.Measured by thermoluminescence(TL) dating,it was found to be formed in MIS2-9... Layer LJ3 of Linjiang stratigraphic section in Dongjiang River valley in the south of the Nanling Mountains is a set of red sandy sediments.Measured by thermoluminescence(TL) dating,it was found to be formed in MIS2-9,500 ± 800 yr to 19,600 ± 1,800 yr B.P.After analy-sis of the grain sizes of the 16 samples(LJ3-100 to LJ3-85) in this layer,it was discovered that(1) The contents of each grain group in dif-ferent samples are similar.(2) The values of Md,Mz,,Sk,and Kg vary from LJ3-100 to LJ3-85 in a narrow range.(3) The segments of each sample in the accumulative curves extend parallel with similar slopes.All the three aspects reveal the Aeolian characteristics of Layer LJ3.Therefore,it is thought that Layer LJ3 consists of red sandy sediments formed in MIS2 in the south of Nanling Mountain,which reflects the arid climate at that time. 展开更多
关键词 Nanling Mountain Range Dongjiang River valley red sandy sediment grain-size analysis arid environment
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ANALYSIS AND CALCULATION OF REGULATED WATER RESOURCES OF GROUNDWATER RESERVOIR 被引量:1
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作者 DAIChang-lei CHIBao-ming GAOShu-qin 《Chinese Geographical Science》 SCIE CSCD 2005年第1期60-63,共4页
Groundwater reservoir is a kind of important engineering, which can optimize water resources arran- gement by means of artificial regulation. Regulated water is the blood and value performance of groundwater reservoir... Groundwater reservoir is a kind of important engineering, which can optimize water resources arran- gement by means of artificial regulation. Regulated water is the blood and value performance of groundwater reservoir. To resolve the problem of real-time quantification of regulated water, the paper analyzed sources and compositions of regulated water in detail. Then, under the conditions of satisfying water demand inside research area, the paper analyzed quantity available and regulation coefficient of different regulated water and established a formula to calculate regulated water. At last, based on a pore groundwater reservoir in the middle reaches of the Yinma River, Jilin Province, the paper calculated regulated water with the formula and the result shows that the method is feasible. With some constraint conditions, the formula can be adopted in other similar areas. 展开更多
关键词 成分化验 水质计算 调节径流 地下水水库
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Analysis of Causes of “7.21” Rainstorm in Zhongwei City
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作者 Bai Ling Nie Jingxin +2 位作者 Yang Yuan Zhang Deyou Gao Jie 《Meteorological and Environmental Research》 CAS 2016年第1期1-4,9,共5页
Conventional information of Micaps, NCEP reanalysis data, and data from regional automatic weather stations were used to analyze the causes of rainstorm in southern mountains of Zhongwei City on July 21,2012. The resu... Conventional information of Micaps, NCEP reanalysis data, and data from regional automatic weather stations were used to analyze the causes of rainstorm in southern mountains of Zhongwei City on July 21,2012. The results showed that the favorable circulation situation " high in east and low in west" to rainfall in Nlngxia formed at 500 hPa before the precipitation appeared, and the heavy rainfall generated when cold air over Lake Baikal moved eastward and joined with warm and wet airflow on the northwest side of 584 line in Hetao region. Ground frontal surface and shear lines at 700 and 500 hPa were main influencing systems of heavy rainfall. Positive vorticity area at low levels, water vapor convergence, as- cending motion and stratification instability provided thermal, dynamic and energy conditions for the formation of the rainstorm. The rainstorm area was situated in wind direction convergence zone where southwest airflow changed into easterly airflow at 700 hPa. Sounding data show that temper- ature and humidity were high in the lower atmosphere which was nearly saturated, and atmospheric convection was unstable before the rainstorm appeared. After the rainstorm occurred, energy in the atmosphere released rapidly, and each index reduced fast, so that the precipitation ended. 展开更多
关键词 RAINSTORM Situation analysis Physical quantities Sounding data China
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Study on the Traffic Energy System Model in Urumqi Based on Scenario Analysis Methods
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作者 Xiaowei Sun Yulei Xie +1 位作者 Zhenghui Fu Hongkuan Zang 《Energy and Power Engineering》 2013年第4期241-246,共6页
In this study, a traffic energy system model is developed to optimize the traffic system cost of Urumqi, considering energy consumption, pollution emission and travel time. Meanwhile, scenario analysis method is propo... In this study, a traffic energy system model is developed to optimize the traffic system cost of Urumqi, considering energy consumption, pollution emission and travel time. Meanwhile, scenario analysis method is proposed to solve the problem of the extreme weather of traffic, and three scenarios (i.e. 10%, 20% and 30%) of reductions of traffic flow quantity and pollutant emission are examined. The results demonstrate that the medium-type coach will be the promising selection under different scenarios especially in the extreme conditions and the traffic flow reduction scenarios are not the better option for the decision owing to the same cost under the different reduction levels. Moreover, encouraging the medium-type coach traveling and restricting the small vehicle driving would be attractive alternatives for the extreme situation. The proposed model would provide reasonable references for decision makers. 展开更多
关键词 TRAFFIC ENERGY System URUMQI SCENARIO analysis POLLUTANT EMISSION TRAFFIC Flow quantity
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Media Representation of Muslims and Islam From 2011-2019: A Meta Analysis
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作者 Sidra Tariq Jamil 《Cultural and Religious Studies》 2020年第1期28-38,共11页
Media is a powerful tool to portray,represent and influence perceptions towards a particular ideology and religion in the present age of technology.Present study presents the findings about the role of media regarding... Media is a powerful tool to portray,represent and influence perceptions towards a particular ideology and religion in the present age of technology.Present study presents the findings about the role of media regarding Muslims and Islamic beliefs and identity.For the purpose a meta-analysis of 353 published studies from were critically reviewed and examined.The detailed quantitative analysis focuses on the geographical distribution,techniques,hypothesis,forms of media and time duration of published data whereas,qualitative analysis examined the most prestigious and well-known studied subject matters.Results from this study give the impression that most of the studies extends to European or western countries and on the other hand Islamic states and media belonged to them have been avoided.Findings also shed light on low volume of comparative studies,lack of perceptibility and scarcity of internet based quality work.A large number of researches focused on the trends of war on terror,links of Muslims in terror related incidences,Islamic extremism and migration.Furthermore,analysis and data of this study reveals the fact of negatively portraying the image and identity of Muslims.The religion of Islam as whole represented as religion associated with extremism,terror,violence and intolerance.Suggestions based on analysis are also taken into account. 展开更多
关键词 MEDIA REPRESENTATION ISLAM Muslims META-analysis Qualitative and QUANTITIES analysis
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Comparative Analysis of Two Snowfall Weather Processes at Nanjing Airport in Early 2022
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作者 Xiaoyin YANG Xin YU 《Meteorological and Environmental Research》 CAS 2022年第6期14-21,共8页
In early 2022,two snowfalls of different magnitudes occurred in southern Jiangsu and Anhui,which had different impacts on the operation of Nanjing Airport.Based on NCEP reanalysis data and the WRF3.9 model,the weather... In early 2022,two snowfalls of different magnitudes occurred in southern Jiangsu and Anhui,which had different impacts on the operation of Nanjing Airport.Based on NCEP reanalysis data and the WRF3.9 model,the weather condition and the physical quantity fields of two different situations were mainly compared and analyzed.The results show that the snowstorm occurred in the left front of the low-level jet stream and in the wind speed convergence area of the 700 h Pa shear line.The reasonable configuration of the convergence area of the water vapor flux divergence and the rising motion field can be regarded as an important reason for the occurrence of the snowstorm.Through the comparative analysis of these two snowfalls of different magnitudes,the focus of the short-term forecast of heavy snowfall at Nanjing Airport was preliminarily drawn:the 0℃line at 700 h Pa basically pressed southward to the south of 31°N,and the 0℃line at 850 h Pa pressed southward to the south of 30°N.Surface temperature was≤0℃,and temperature at 925-800 h Pa was≤-3 or-4℃;temperature at 700 h Pa was<0℃,and there was temperature inversion in the middle and lower troposphere.In the model forecast output field,the proportion of the mixing ratio of frozen precipitation in the near-surface atmosphere to the mixing ratio of water vapor that can condense into precipitation is very important,and can be used to determine the evolution of rain and snow boundaries and sleet areas or the south of rain and snow transition zone and precipitation phase. 展开更多
关键词 SNOWFALL Physical quantity field Comparative analysis
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Analysis and Forecast on the Car Market of Our Country
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作者 李瑞 梁庆文 《Chinese Quarterly Journal of Mathematics》 CSCD 1999年第1期55-61, ,共7页
This paper is intended to forecast the demand of the car market and the quantity of car possession in our country in 2000 by means of two statistics methods, i.e. tendency inference and regression analysis, and then i... This paper is intended to forecast the demand of the car market and the quantity of car possession in our country in 2000 by means of two statistics methods, i.e. tendency inference and regression analysis, and then its future growth tendency and market demand in our country are analyzed, according to the strategy requirement and the actual facts of our car industry development. 展开更多
关键词 中国 轿车 市场分析 预测
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初次和重复献血不足量特征及原因分析
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作者 王振兴 黄志森 +4 位作者 黄东虹 李姗丹 陈少彬 陈庆恺 揭小梅 《黑龙江医学》 2024年第12期1443-1446,共4页
目的:分析初次和重复不足量献血者的人群特征和相关影响因素,为进一步降低献血不足量的发生率提供依据。方法:回顾性调查2020年1月1日—2021年12月31日某市全血不足量献血者的献血资料,统计不足量献血者相关数据,比较初次和重复献血者... 目的:分析初次和重复不足量献血者的人群特征和相关影响因素,为进一步降低献血不足量的发生率提供依据。方法:回顾性调查2020年1月1日—2021年12月31日某市全血不足量献血者的献血资料,统计不足量献血者相关数据,比较初次和重复献血者不足量的原因。结果:本站全血献血者不足量发生率为1.03%,初次献血者发生率为1.52%,高于重复献血者0.59%,差异有统计学意义(χ^(2)=363.69,P<0.05);在初次献血者中年龄18~25岁不足量发生率为2.40%高于其他年龄组的1.22%、0.94%、0.89%、0,差异有统计学意义(χ^(2)=222.786,P<0.05);体重≤55 kg的发生率为1.89%高于体重>55 kg的发生率为1.40%,差异有统计学意义(χ^(2)=24.291,P<0.05);高校和集体献血不足量发生率最高,分别为2.81%和1.61%,差异有统计学意义(χ^(2)=176.890、12.693,P<0.05);目标献血量400 mL发生率为1.84%高于300 mL发生率为1.41%,差异有统计学意义(χ^(2)=18.916,P<0.05);初次与重复献血者发生不足量的原因由高到低排列顺序是一致的,主要原因是精神紧张和血流不畅,差异有统计学意义(χ^(2)=107.916、48.822,P<0.05)。结论:初次和重复献血者发生不足量的主要原因是精神紧张,重点关注初次献血者中年龄18~25岁、体重≤55 kg、目标血量400 mL的高校群体,应采取针对性预防措施,预防献血不足量的发生,减少血液报废和保障献血者安全。 展开更多
关键词 不足量 献血者 分析
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筛析法分析砂砾质样品的取样质量估算——对现行国标有关规定的扩展讨论
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作者 宗羿冰 陈奇 +3 位作者 朱永兰 唐雯雯 蔡廷禄 贾建军 《海洋与湖沼》 CAS CSCD 北大核心 2024年第2期386-396,共11页
筛析法是硬件要求低、操作简便、应用广泛的一种碎屑沉积物粒度分析方法。对于砂砾质沉积物而言,在具体的粒度分析实验中,应该取用多少质量的样品进行筛析,目前尚缺乏完备的、科学内涵明确的技术规范。《海洋调查规范第8部分:海洋地质... 筛析法是硬件要求低、操作简便、应用广泛的一种碎屑沉积物粒度分析方法。对于砂砾质沉积物而言,在具体的粒度分析实验中,应该取用多少质量的样品进行筛析,目前尚缺乏完备的、科学内涵明确的技术规范。《海洋调查规范第8部分:海洋地质地球物理调查》对此问题给出了部分解决方案,但其原理不明,也未能包括砂砾质沉积物的主要粒径范围。本研究针对筛析法取样质量的估算问题展开分析与讨论,基于概率分布理论推导出一套适用于砂砾质样品的筛析法取样质量估算公式,给出了不同分选系数下(0.35Φ~4.00Φ)样品最大颗粒直径对应的理论取样最小量的范围。研究表明,现行海洋调查规范的最大颗粒直径与取样最小量之间的定量关系可能是基于正态分布、分选极差的下界(σ=4.00Φ)的情况推算而来的;可将筛析法取样质量估算表的最大颗粒直径扩展至64 mm,该粒径对应的理论取样最小量为47.8 kg。为了检验推导的公式,以浙江省舟山群岛和象山半岛的潮间带近200个砂砾质样品为例,计算了样品最大颗粒直径对应的筛析法理论取样最小量及其理想状态下的正态粒度分布,并与实际样品的取样量及粒度分布分析结果进行了对比。结果显示,大部分样品的粒度分析结果近似正态分布,理论分析取样量与实际取样量的相关性较为理想。上述工作,可以为海洋调查规范的修订提供参考。 展开更多
关键词 筛析法 砂砾质沉积物 采样质量 取样质量 分选系数
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蜀葵品种的数量分类研究
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作者 陈曦 李意峰 +7 位作者 刘才磊 李秀 贾茵 潘远智 姜贝贝 朱章顺 李方文 刘晓莉 《安徽农业大学学报》 CAS CSCD 2024年第3期376-383,共8页
为了探究在蜀葵品种分类中起到关键作用的指标以及建立全面的蜀葵品种分类系统,以75个蜀葵品种为研究材料,对各品种的性状进行观测,选定26个性状指标进行R型聚类分析和主成分分析,去掉相关性较大且累积贡献率较小的性状指标,然后对75个... 为了探究在蜀葵品种分类中起到关键作用的指标以及建立全面的蜀葵品种分类系统,以75个蜀葵品种为研究材料,对各品种的性状进行观测,选定26个性状指标进行R型聚类分析和主成分分析,去掉相关性较大且累积贡献率较小的性状指标,然后对75个蜀葵品种进行Q型聚类分析。R型聚类分析结果显示:除了少数指标相关性较大外,其他指标较为分散,指标选取合理。主成分分析的结果显示:26个指标可综合为8个主成分,累计贡献率达82.818%;Q型聚类分析的结果显示:75个品种在不同等级结合线处可以被分为2类、3类、4类和5类,其中叶型、裂叶长/叶长、花型、雌雄蕊瓣化情况、花期早晚、花瓣数、花色等指标在分类中有较大的影响力。叶型和花型是蜀葵品种分类最主要的标准和依据。因此,可以将蜀葵品种划分为圆叶品种群、裂叶品种群及全裂叶品种群三大品种群。 展开更多
关键词 蜀葵 品种 数量分类 聚类分析 主成分分析
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新疆地区农田地膜残留影响因素及污染强度评价
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作者 李慧军 刘勤 +4 位作者 周明冬 武红旗 刘晓伟 夏雪梅 何文清 《农业资源与环境学报》 CAS CSCD 北大核心 2024年第3期656-665,共10页
为探明新疆地区地膜残留污染强度和污染分布情况,选择新疆地区625个有效点位进行问卷调查和实地采样,通过熵权法、层次分析法进行组合赋权,对地膜残留影响因素地块面积、距村距离、覆膜年限、覆膜比例进行权重计算,根据权重系数优化聚... 为探明新疆地区地膜残留污染强度和污染分布情况,选择新疆地区625个有效点位进行问卷调查和实地采样,通过熵权法、层次分析法进行组合赋权,对地膜残留影响因素地块面积、距村距离、覆膜年限、覆膜比例进行权重计算,根据权重系数优化聚类指标,对2021年地膜残留污染数据进行聚类分析。结果表明:不同地块面积、距村距离、覆膜年限、覆膜比例影响因素下地膜残留量差异极显著(P<0.01),权重系数分别为0.200、0.315、0.265、0.220。优化聚类指标后的K-means聚类分析将新疆地区地膜污染数据分为四类,地膜残留量第Ⅰ类<第Ⅱ类<第Ⅲ类<第Ⅳ类,地膜平均残留量依次为63、100、110、135 kg·hm^(-2),聚类分析的结果符合客观实际,且受到地膜残留影响因素影响。依据聚类结果的地膜残留量划分出低污染、中污染、高污染三个强度等级,不同级别之间具有明显的分布差异。研究表明:新疆地区农田地膜总体污染强度呈现中部高、南北低的分布状态,应重视高污染等级的点位和地区,有针对性地采取相应管理措施,加快地膜残留污染治理进程,进而保护农业可持续发展。 展开更多
关键词 地膜 残留量 影响因素 聚类分析 新疆地区 污染强度
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基于流场分析的煤焦化储罐集气罩结构优化
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作者 郭涛 朱博韬 +3 位作者 王雅玲 张治宁 张亚新 郭皓 《新疆大学学报(自然科学版中英文)》 CAS 2024年第2期236-245,共10页
集气罩是一种用来进行气体收集的装置,为研究煤焦化储罐集气罩结构对其内部流场的影响,采用计算流体力学(CFD)中的FLUENT软件模拟了开口角度为60°、90°和120°的锥形开口、开口弧度为30°、45°和55°的弧形... 集气罩是一种用来进行气体收集的装置,为研究煤焦化储罐集气罩结构对其内部流场的影响,采用计算流体力学(CFD)中的FLUENT软件模拟了开口角度为60°、90°和120°的锥形开口、开口弧度为30°、45°和55°的弧形开口以及末端加装高度为50 mm、100 mm和150 mm的扩压罩时,集气罩内部的流场变化规律.结果表明:开口为弧形、开口弧度为45°且末端加装高度为100 mm扩压罩的集气罩内部流场分布更均匀,具有更小的出口速度和更少的配风量.通过对不同开口角度、不同开口弧度及加装不同高度的扩压罩后集气罩内部流场特性的分析表明,改变开口形式和末端加装适当高度的扩压罩能大幅减小集气罩的配风量. 展开更多
关键词 集气罩 数值模拟 流场分析 结构优化 配风量
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小样本量下浙江省猪鸡源肠球菌对停、限用抗菌药物最小抑菌浓度分布变迁的追踪分析
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作者 周炜 沈红霞 +6 位作者 陈洁 周芷锦 应永飞 吕伟军 王彬 唐标 胡理明 《中国兽药杂志》 2024年第6期7-16,共10页
为追踪了解浙江省猪鸡源肠球菌对停、限用抗菌药物耐药性变化趋势,利用微量肉汤稀释法对2019-2023年间浙江省40家猪鸡养殖场的肠球菌耐药性进行了持续跟踪监测。在小样本量条件下,基于MIC分布曲线、MIC50和耐药系数方法,评估了这些肠球... 为追踪了解浙江省猪鸡源肠球菌对停、限用抗菌药物耐药性变化趋势,利用微量肉汤稀释法对2019-2023年间浙江省40家猪鸡养殖场的肠球菌耐药性进行了持续跟踪监测。在小样本量条件下,基于MIC分布曲线、MIC50和耐药系数方法,评估了这些肠球菌对吉他霉素、黄霉素、恩拉霉素、那西肽、维吉尼亚霉素、杆菌肽和氧氟沙星7种停、限用抗菌药的最小抑菌浓度的变化趋势。结果表明,鸡源和猪源肠球菌对杆菌肽的耐受水平下降趋势明显;对吉他霉素、黄霉素和恩拉霉素的耐受水平总体呈下行趋势,其中吉他霉素和黄霉素表现为先升后降,恩拉霉素则表现为先降后升;对那西肽、维吉尼亚霉素均相对较为敏感,但低浓度MIC值的菌株略有增多;对氧氟沙星呈现出物种差异,鸡源肠球菌相对较为敏感,且耐受水平有进一步下行的趋势,猪源肠球菌对氧氟沙星耐受水平相对较高,且中等浓度MIC值菌株数于2022年出现较大幅度上升。 展开更多
关键词 小样本量 追踪分析 肠球菌 抗菌药 最小抑菌浓度 分布
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