期刊文献+
共找到6篇文章
< 1 >
每页显示 20 50 100
Study on the Change Rules of Ningqi 1 and Meteorological Factors in Qaidam Basin
1
作者 樊光秀 罗显发 李成桃 《Meteorological and Environmental Research》 CAS 2010年第6期36-38,共3页
[Objective] The change rules of Lycium barbarum and meteorological factors in Qaidam Basin were studied. [Method] Botanical characteristics,growth characteristics and physiological factor changes of Ningqi 1 were anal... [Objective] The change rules of Lycium barbarum and meteorological factors in Qaidam Basin were studied. [Method] Botanical characteristics,growth characteristics and physiological factor changes of Ningqi 1 were analyzed,and the change laws of Ningqi 1 and environmental factors(including sunlight,temperature,water and soil) were investigated by using meteorological observation data in 1973-2008. [Results] The results showed that Ningqi 1 belonged to light preferring plant,and the higher photosynthetic rate showed double peak type with the peaks appearing at 12:00 and 16:00,having midday depression of photosynthesis. The diurnal variation of transpiration rate in leaves showed a double peak,and the temperature around leaves was 0.2-0.5 ℃ higher than that in the field. The average relative humidity and temperature were the key factors to affect forming L. barbarum fruits. The suitable temperature for developing big seeds was 18 ℃. [Conclusions] Ningqi 1 could be taken as the first choice variety to plant and popularize in Qaidam Basin. 展开更多
关键词 Qaidam Basin Ningqi 1 Meteorological factors change rule China
下载PDF
A New Method Based on Association Rules Mining and Geo-filter for Mining Spatial Association Knowledge 被引量:6
2
作者 LIU Yaolin XIE Peng +3 位作者 HE Qingsong ZHAO Xiang WEI Xiaojian TAN Ronghui 《Chinese Geographical Science》 SCIE CSCD 2017年第3期389-401,共13页
Association rule mining methods, as a set of important data mining tools, could be used for mining spatial association rules of spatial data. However, applications of these methods are limited for mining results conta... Association rule mining methods, as a set of important data mining tools, could be used for mining spatial association rules of spatial data. However, applications of these methods are limited for mining results containing large number of redundant rules. In this paper, a new method named Geo-Filtered Association Rules Mining(GFARM) is proposed to effectively eliminate the redundant rules. An application of GFARM is performed as a case study in which association rules are discovered between building land distribution and potential driving factors in Wuhan, China from 1995 to 2015. Ten sets of regular sampling grids with different sizes are used for detecting the influence of multi-scales on GFARM. Results show that the proposed method can filter 50%–70% of redundant rules. GFARM is also successful in discovering spatial association pattern between building land distribution and driving factors. 展开更多
关键词 data mining association rules rules spatial visualization driving factors analysis land use change
下载PDF
Changing Rule of Physical and Chemical Indicators of Sediment in Tilapia Aquaculture Ponds
3
作者 裘丽萍 李志波 +4 位作者 宋超 张聪 郑尧 孙博 陈家长 《Agricultural Science & Technology》 CAS 2016年第3期690-693,699,共5页
To provide basic information for studying balancing mechanism of nutrition environment in aquaculture ponds, sediment samples were collected periodically during the breeding process of tilapia in ponds. Then various t... To provide basic information for studying balancing mechanism of nutrition environment in aquaculture ponds, sediment samples were collected periodically during the breeding process of tilapia in ponds. Then various types of nutrient content of the samples were detected and the changing rule was summarized. The results showed that dry weight of the sediment and content of TP, TN and TOC generally presented a trend of first increasing and then decreasing. The main production period of each nutrient was from July to September and the production percentage was close to 80% of the total production. The content of NH4^+-N increased gradually and reached a peak in early August, then maintained at the peak level. NO2^--N content of the sediment in each pond was basically the same in the earlier aquaculture stage and decreased in middle stage with a big difference, then rose again in the later stage. 展开更多
关键词 TILAPIA SEDIMENT Physical and chemical indicators Changing rule
下载PDF
The dynamic changes of genes revealed that persistently overexpressed genes drive the evolution of cyflumetofen resistance in Tetranychus cinnabarinus
4
作者 Kaiyang Feng Jialu Liu +5 位作者 Mingyu Zhao Zhixin Jiang Peilin Liu Peng Wei Wei Dou Lin He 《Insect Science》 SCIE CAS CSCD 2023年第4期1129-1148,共20页
Changes in gene expression are associated with the evolution of pesticide resis-tance in arthropods.In this study,transcriptome sequencing was performed in 3 different resistance levels(low,L;medium,M;and high,H)of cy... Changes in gene expression are associated with the evolution of pesticide resis-tance in arthropods.In this study,transcriptome sequencing was performed in 3 different resistance levels(low,L;medium,M;and high,H)of cyflumetofen-resistant strain(YN-CyR).A total of 1685 genes,including 97 detoxification enzyme genes,were upregulated in all 3 stages,of which 192 genes,including 11 detoxification enzyme genes,showed a continuous increase in expression level with resistance development(L to H).RNA in-terference experiments showed that overexpression of 7 genes(CYP392A1,TcGSTd05,CCE06,CYP389A1,TcGSTz01,CCE59,and CYP389C2)is involved in the development of cyflumetofen resistance in Tetranychus cinnabarinus.The recombinant CYP392A1 can effectively metabolize cyflumetofen,while CCE06 can bind and sequester cyflumetofen in vitro.We compared 2 methods for rapid screening of resistance molecular markers,in-cluding short-term induction and 1-time high-dose selection.Two detoxification enzyme genes were upregulated in the field susceptible strain(YN-S)by induction with 20%lethal concentration(LC2o)of cyflumetofen.However,16 detoxification enzyme genes were up-regulated by 1-time selection with LCso of cyflumetofen.Interestingly,the 16 genes were overexpressed in all 3 resistance stages.These results indicated that 1685 genes that were upregulated at the L stage constituted the basis of cyflumetofen resistance,of which 192 genes in which upregulation continued to increase were the main driving force for the de-velopment of resistance.Moreover,the 1-time high-dose selection is an efficient way to rapidly obtain the resistance-related genes that can aid in the development of resistance markers and resistance management in mites. 展开更多
关键词 change rules cyflumetofen detoxification enzyme genes resistance molec-ular markers Tetranychus cinnabarinus
原文传递
Study on Acoustic Emission Characteristics of Self-Compacting Concrete under Uniaxial Compression Test
5
作者 Yongshuai Sun Guihe Wang Yixuan li 《Journal of Renewable Materials》 SCIE EI 2022年第8期2287-2302,共16页
To study the relationship between acoustic emission characteristic parameters of self-compacting concrete(SCC)and its destruction evolution,under uniaxial compression,acoustic emission(AE)tests are performed on C30 se... To study the relationship between acoustic emission characteristic parameters of self-compacting concrete(SCC)and its destruction evolution,under uniaxial compression,acoustic emission(AE)tests are performed on C30 selfcompacting concrete test blocks that are preserved for 7 days and 28 days,the corresponding relationship among energy,amplitude,ring count and different failure stages of the specimens are analyzed by AE experiment,and the spatial distribution of AE in each stage is described by introducing location map.The test shows that there are two rules for the failure of SCC specimens cured for 7 days and 28 days:(1)The first failure law is divided into four stages according to the percentage of the stress value reaching the limit stress:Initial stage:above 10%,the compaction time of test block cured for 28 days is relatively low;Elastic failure stage:30%–35%,the cumulative value of each parameter increases linearly,and the cumulative value of the amplitude is the largest;Crack stable propagation stage:35%–90%,there is a moment that causes local stress concentration in both test blocks;Active stage:above 90%,the cumulative value of the parameter rises sharply,then continues to load the test block instability and damage.(2)The second failure law is divided into five stages according to the percentage of the stress value reaching the limit stress:Initial stage:15%–20%,the cumulative value of each parameter increases with time;Elastic failure stage:20%–40%,the cumulative value of the parameter continues to grow,but the growth curve is approximately parallel;Crack stable propagation stage:40%–60%,all parameters increased sharply and the increase reached the peak of the whole process;A stable state:60–80%,the emission characteristic parameter will become zero,and the stable state of the 28 days curing test block is lagging;Active stage:above 90%,the number of signals increased sharply,but the energy and amplitude are low,and the later test block is completely fractured.(3)In the process of failure,the test block of SCC will form an inverted triangle or landslide failure surface,and the part above the failure surface is prone to failure,and there is a tendency to leave the test block.(4)Under uniaxial compression,the penetration of SCC cracks is mostly shear penetration. 展开更多
关键词 Acoustic emission change rule damage localization self-compacting concrete uniaxial compression
下载PDF
Concrete Physics Method for Solving NP hard Problem
6
作者 Huang Wen\|qi College of Computer Science, Huazhong University of Science and Technology, Wuhan 430074,China Laboratory of Computer Science, Institute of Software, Chinese Academy of Sciences, Beijing 100080, China 《Wuhan University Journal of Natural Sciences》 CAS 2001年第Z1期140-146,共7页
With a NP hard problem given, we may find a equivalent physical world. The rule of the changing of the physical states is simply the algorithm for solving the original NP hard problem .It is the most natural algorithm... With a NP hard problem given, we may find a equivalent physical world. The rule of the changing of the physical states is simply the algorithm for solving the original NP hard problem .It is the most natural algorithm for solving NP hard problems. In this paper we deal with a famous example , the well known NP hard problem——Circles Packing. It shows that our algorithm is dramatically very efficient. We are inspired that, the concrete physics algorithm will always be very efficient for NP hard problem. 展开更多
关键词 concrete physics algorithm NP hard problem circles packing the rule of the changing of the physical states
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部