期刊文献+
共找到31,248篇文章
< 1 2 250 >
每页显示 20 50 100
Urban-Rural Gap Widens
1
《China Population Today》 2000年第Z2期14-15,共2页
关键词 HIGH urban-rural gap Widens
在线阅读 下载PDF
An empirical research of urbanization and urban-rural gap in China:1952-2005
2
作者 Ye Chao Cao Zhidong Chen Mingxing 《Ecological Economy》 2008年第4期403-409,共7页
There are two important problems of urban-rural relationship in China nowadays: the accelerated urbanization process and an enlarged urban-rural gap. The researchers can be divided into two schools according to their ... There are two important problems of urban-rural relationship in China nowadays: the accelerated urbanization process and an enlarged urban-rural gap. The researchers can be divided into two schools according to their emphasis. One emphasizes particularly the urban development, and the other pays attention to the urban-rural income gap. However, there is a very strong association between urbanization rate and urban-rural inequality. As far as it goes, there is a paradox between urbanization and urban-rural inequality in China. This main reason lies' in the different temporal and spatial scales chosen by the scholars. Making use of correlative analysis and wavelet method, this paper rethinks and sums up the commonly evolving characteristics and trends between urbanization and urban-rural gap from 1950s to now. There is an intensively positive correlation between urbanization and urban- rural consumption gap. In general, with the acceleration of urbanization, urban-rural gap of China has undergone three stages of cyclical fluctuations. The rapid urbanization results in the increase of urban-rural highly risky. In addition, the special stage of urbanization is the other reason that expands urban-rural gap. 展开更多
关键词 URBANIZATION urban-rural relation urban-rural gap Correlative analysis Wavelet analysis
在线阅读 下载PDF
Mechanisms and Pathways for the Cultural Tourism Industry to Empower Integrated Urban-Rural Development in the Digital Era
3
作者 Zhou Jin Cao Yang Li Han 《Contemporary Social Sciences》 2025年第3期63-82,共20页
Integrated urban-rural development is a crucial stage in the development of China’s urban-rural relations and is essential for Chinese modernization.In the digital era,the cultural tourism industry has the potential ... Integrated urban-rural development is a crucial stage in the development of China’s urban-rural relations and is essential for Chinese modernization.In the digital era,the cultural tourism industry has the potential to promote integrated urban-rural development through multidimensional integration mechanisms,including cultural exchanges,resource sharing,and industrial linkages.Specifically,by innovating cultural tourism development models,the efficiency of labor allocation between urban and rural areas can be improved,fostering the transformation of rural cultural tourism and its related industries.By expanding the cultural tourism scenarios,new spaces for rural cultural consumption can be constructed,which would help to reduce urban and rural consumption disparities.By establishing cultural tourism development platforms and facilitating the sharing of data elements,the coordinated development of urban and rural public cultural services can be promoted,which would reduce the service gaps between urban and rural areas.By leveraging smart city construction to drive the development of the rural digital infrastructure,integrated urban-rural development,guided by a“digital+”approach,can then be fostered and help to reduce urban and rural development gaps.Building on this foundation,the digital transformation of cultural tourism will advance industrial linkages,resource sharing,factor mobility,and spatial co-creation within urban and rural cultural tourism,gradually realizing integrated urban-rural development and ultimately driving rural revitalization and fostering common prosperity. 展开更多
关键词 digital era cultural tourism urban-rural integration rural revitalization
在线阅读 下载PDF
National age-specific mortality trends for cervical and breast cancers in urban-rural areas of China from 2009 to 2021:a population-based analysis
4
作者 Meng-Long Li Jin-Lei Qi +8 位作者 Ya-Qi Ma Wen Shu Hui-Di Xiao Li-Jun Wang Peng Yin Hao-Yan Guo Sten H.Vermund Mai-Geng Zhou Yi-Fei Hu 《Military Medical Research》 2025年第5期727-740,共14页
Background:Cervical and breast cancers are among the top 4 leading causes of cancer-related mortality in women.This study aimed to examine age-specific temporal trends in mortality for cervical and breast cancers in u... Background:Cervical and breast cancers are among the top 4 leading causes of cancer-related mortality in women.This study aimed to examine age-specific temporal trends in mortality for cervical and breast cancers in urban and rural areas of China from 2009 to 2021.Methods:Age-specific mortality data for cervical and breast cancers among Chinese women aged 20-84 years were obtained from China’s National Disease Surveillance Points system spanning the years 2009 to 2021.Negative binomial regression models were utilized to assess urban-rural differences in mortality rate ratios,while Joinpoint models with estimated average annual percent changes(AAPC)and slopes were employed to compare temporal trends and the acceleration of mortality rates within different age groups.Results:From 2009 to 2021,there was a relative increase in age-specific mortality associated with the two cancers observed in rural areas compared with urban areas.A rising trend in the screening age of 35-64[AAPC:4.0%,95%confidence interval(CI)0.5-7.6,P=0.026]for cervical cancer was noted in rural areas,while a stable trend(AAPC:-0.7%,95%CI-5.8 to 4.6,P=0.780)was observed in urban areas.As for breast cancer,a stable trend(AAPC:0.3%,95%CI-0.3 to 0.9,P=0.280)was observed in rural areas compared to a decreasing trend(AAPC:-2.7%,95%CI-4.6 to-0.7,P=0.007)in urban areas.Urban-rural differences in mortality rates increased over time for cervical cancer but decreased for breast cancer.Mortality trends for both cervical and breast cancers showed an increase with age across 4 segments,with the most significant surge in mortality observed among the 35-54 age group across urban and rural areas,periods,and regions in China.Conclusions:Special attention should be given to women aged 35-54 years due to mortality trends and rural-urban disparities.Focusing on vulnerable age groups and addressing rural-urban differences in the delivery of cancer control programs can enhance resource efficiency and promote health equity. 展开更多
关键词 Cervical cancer Breast cancer Age-specific mortality TREND urban-rural difference Joinpoint model China
原文传递
A Research on the Threshold Effect of Credit Rationingupon the Urban-rural Income Gap in Rural Areas
5
作者 郑平 刘艳华 《石家庄经济学院学报》 2016年第3期68-77,共10页
在剖析了信贷配给与城乡收入差距之间作用机制的基础上,论文构建了信贷配给与城乡收入差距的面板门槛模型,选取3 1 个省市1987年- 201 3年的省级面板数据,运用面板门槛模型估计方法,实证分析信贷配给对城乡收入差距的影响,并且从区域层... 在剖析了信贷配给与城乡收入差距之间作用机制的基础上,论文构建了信贷配给与城乡收入差距的面板门槛模型,选取3 1 个省市1987年- 201 3年的省级面板数据,运用面板门槛模型估计方法,实证分析信贷配给对城乡收入差距的影响,并且从区域层面进行了比较分析.结果显示:降低信贷配给程度有助于缓解城乡收入差距,而从东部、中部、西部三大区域的实证结果来看,各地区的信贷配给程度的提升对城乡收入差距的扩大有不同程度的影响.最后根据研究结果,提出降低各地区农业信贷配给程度的措施,从而达到缩小城乡收入差距的目的. 展开更多
关键词 信贷配给 城乡收入差距 面板门槛
在线阅读 下载PDF
Mapping and measuring urban-rural inequalities in accessibility to social infrastructures 被引量:2
6
作者 Chenmeng Guo Weiqi Zhou +1 位作者 Chuanbao Jing Dawa Zhaxi 《Geography and Sustainability》 CSCD 2024年第1期41-51,共11页
Equal access to social infrastructures is a fundamental prerequisite for sustainable development,but has long been a great challenge worldwide.Previous studies have primarily focused on the accessibility to social inf... Equal access to social infrastructures is a fundamental prerequisite for sustainable development,but has long been a great challenge worldwide.Previous studies have primarily focused on the accessibility to social infras-tructures in urban areas across various scales,with less attention to rural areas,where inequality can be more severe.Particularly,few have investigated the disparities of accessibility to social infrastructures between urban and rural areas.Here,using the Changsha-Zhuzhou-Xiangtan urban agglomeration,China,as an example,we investigated the inequality of accessibility in both urban and rural areas,and further compared the urban-rural difference.Accessibility was measured by travel time of residents to infrastructures.We selected four types of social infrastructures including supermarkets,bus stops,primary schools,and health care,which were funda-mentally important to both urban and rural residents.We found large disparities in accessibility between urban and rural areas,ranging from 20 min to 2 h.Rural residents had to spend one to two more hours to bus stops than urban residents,and 20 min more to the other three types of infrastructures.Furthermore,accessibility to multiple infrastructures showed greater urban-rural differences.Rural residents in more than half of the towns had no access to any infrastructure within 15 min,while more than 60%of the urban residents could access to all infrastructures within 15 min.Our results revealed quantitative accessibility gap between urban and rural areas and underscored the necessity of social infrastructures planning to address such disparities. 展开更多
关键词 ACCESSIBILITY Social infrastructures urban-rural difference INEQUALITY Regional sustainability
在线阅读 下载PDF
AlH_(3)/GAP胶表界面的相互作用
7
作者 毛家淦 李洪旭 +6 位作者 武卓 徐爽 余方源 赵志坤 彭圆坤 熊文博 哈恒欣 《火炸药学报》 北大核心 2025年第6期568-573,共6页
通过电子万能材料试验机测试了AlH_(3)等质量和等体积替换Al粉对GAP/AlH_(3)推进剂力学性能的影响;采用扫描电镜(SEM)观察了Al粉和AlH_(3)的形貌;采用接触角法研究了Al粉和AlH_(3)与GAP的浸润性;采用原位拉伸扫描电镜、动态热机械分析(D... 通过电子万能材料试验机测试了AlH_(3)等质量和等体积替换Al粉对GAP/AlH_(3)推进剂力学性能的影响;采用扫描电镜(SEM)观察了Al粉和AlH_(3)的形貌;采用接触角法研究了Al粉和AlH_(3)与GAP的浸润性;采用原位拉伸扫描电镜、动态热机械分析(DMA)等方法研究了AlH_(3)/GAP复合物的界面黏接性能。结果表明,用AlH_(3)等质量和等体积替换Al粉,推进剂的抗拉强度和模量都升高,伸长率都降低;Al粉形状为球体,而AlH_(3)粉末形状为立方体;Al与GAP的黏附功(80.5 mN/m)小于AlH_(3)与GAP的黏附功(130.6 mN/m),而Al与GAP的界面张力(52.6 mN/m)大于AlH_(3)与GAP的界面张力(29.4 mN/m),说明AlH_(3)与GAP的浸润性优于铝粉;AlH_(3)/GAP复合物在拉伸过程中不存在明显的脱湿问题,界面黏接情况良好。 展开更多
关键词 材料力学 AlH_(3) 三氢化铝 gap 界面张力 gap推进剂
在线阅读 下载PDF
Preliminary Study on Effects of the Model of Community-supported Agriculture(CSA) on Urban-rural Income Gap in China
8
作者 彭雅琴 扈立家 《Agricultural Science & Technology》 CAS 2015年第2期404-406,410,共4页
The urban-rural income gap is widening,which has become a bottleneck restricting China's economic and social development.It is the current outstanding problems in the harmonious development of the society.Community S... The urban-rural income gap is widening,which has become a bottleneck restricting China's economic and social development.It is the current outstanding problems in the harmonious development of the society.Community Supported Agriculture(CSA) is one of the most important forms of sustainable agriculture and it has received the attention in recent years.This paper first introduces the rise and development of CSA in China,and discuss the impact of CSA on urban-rural income gap in China preliminarily in order to provide ideas for improving the farmers' income and narrowing the income gap between urban and rural areas. 展开更多
关键词 Community Supported Agriculture(CSA) The urban-rural income gap The income of the farmers
在线阅读 下载PDF
The Approaches to Narrowing Urban-Rural Income Gap——From the Perspective of Rural Social Security 被引量:3
9
作者 ZHENG Shuang-sheng 《Asian Agricultural Research》 2010年第6期37-40,45,共5页
From the situations about the incomes and life quality of the urban and rural residents,the thesis briefly introduces the status quo of the urban-rural income gap and explores the impact of the income gap on social ec... From the situations about the incomes and life quality of the urban and rural residents,the thesis briefly introduces the status quo of the urban-rural income gap and explores the impact of the income gap on social economy:firstly,it hampers economic development;secondly,it is detrimental to the social development.Then the thesis analyzes the role of a sound social security in narrowing urban-rural income gap:at first,it broadens the institutional environment of improving the agricultural efficiency;secondly,it eliminates the uncertainties influencing the farmers' income;thirdly,it improves the farmers' capacity to increase income;at last,it enhances the farmers' consciousness of wealth.Next the thesis inquires into the problems existing in the system of rural social security:the first problem is more obviously fragmented system;the second is inadequate security projects and narrower coverage;the third is an obvious lack of equality in urban and rural security;the fourth is even less sound management system;the last is the lagging of legislation.Afterwards the thesis proposes the countermeasures and suggestions to improve the system of rural social security and narrow urban-rural income gap:firstly,to integrate the social security system in rural areas;secondly,to perfect security projects and enhance the security system;thirdly,to integrate the administrative management of social security;at last,to enforce the legal system. 展开更多
关键词 Income distribution urban-rural income gap Rural social security Urban and rural residents China
在线阅读 下载PDF
探索中药材质量优化:GAP、HACCP和ISO体系的综合运用
10
作者 俸世洪 叶霄 赵文吉 《中国中医药信息杂志》 CAS 2025年第1期30-34,共5页
中医药在世界范围内的应用增加,但我国中医药产品进入国际市场仍面临东西方文化差异、中药质量标准不完善、全球针对植物药的政策壁垒、中药材质量不达标等问题。2022年《中药材生产质量管理规范》引入危害分析与关键控制点理念,对中药... 中医药在世界范围内的应用增加,但我国中医药产品进入国际市场仍面临东西方文化差异、中药质量标准不完善、全球针对植物药的政策壁垒、中药材质量不达标等问题。2022年《中药材生产质量管理规范》引入危害分析与关键控制点理念,对中药材生产中的危害因素进行控制;同时,国际标准化组织中医药技术委员会ISO/TC249成立后,建立中医药国际标准,中医药企业开展GAP和ISO双认证,从源头上控制中医药的质量,是我国中医药扩大国际市场份额的根本途径。本文通过GAP、HACCP和ISO体系在中药材质量控制应用现状的对比研究,提出我国的中药材生产规范要充分借鉴国际上其他质量管理体系的优点,在降低生产风险和成本的同时,使GAP更具有操作性。 展开更多
关键词 中药材 gap体系 HACCP体系 ISO体系 质量控制
暂未订购
Influence of Transportation Accessibility on Urban-rural Income Disparity and Its Spatial Heterogeneity 被引量:1
11
作者 HUANG Xiaoyan KANG Chenchen +1 位作者 YIN Chun TANG Junqing 《Chinese Geographical Science》 SCIE CSCD 2024年第3期453-467,共15页
Transportation accessibility has been treated as an important means of reducing the urban-rural income disparity.However,only a few studies have examined the effects of different types of transportation accessibility ... Transportation accessibility has been treated as an important means of reducing the urban-rural income disparity.However,only a few studies have examined the effects of different types of transportation accessibility on urban-rural income disparity and their spatial heterogeneity.Based on data from 285 prefecture-level(and above)Chinese cities in 2000,2005,2010,2015,and 2020,this study uses spatial econometric models to examine how highway accessibility and railway accessibility influence the urban-rural income disparity and to identify their spatial heterogeneity.The result reveals that highway accessibility and railway accessibility have‘coreperiphery’ring-like circle structures.The urban-rural income disparity exhibits strong spatial clustering effects.Both highway accessibility and railway accessibility are negatively associated with urban-rural income disparity,and the former having a greater effect size.Moreover,there is a substitution effect between highway accessibility and railway accessibility in the whole sample.Furthermore,these associations differ in geographic regions.In the central region,highway accessibility is more important in reducing the urban-rural income disparity,but its effect is weakened with the increase of railway accessibility.In the western region,railway accessibility has a larger effect on narrowing the urban-rural income disparity,and this effect is strengthened by the increase of highway accessibility.We conclude that improving transportation accessibility is conducive to reducing the urban-rural income disparity but its effect is spatial heterogenetic.Highways and railways should be developed in a coordinated manner to promote an integrated transport network system. 展开更多
关键词 transport accessibility income gap regional divergence spatial heterogeneity urban and rural areas China
在线阅读 下载PDF
Granger Causality Test of Urban-rural Income Gap and Employment of Rural Labor Forces——A Case Study of Shouguang City 被引量:2
12
作者 LU Gui-xing Weifang University, Weifang 261061, China 《Asian Agricultural Research》 2012年第1期36-39,70,共5页
Taking Shouguang City in Shandong Province as an example, this article researches the mutual relationship between urban-rural income and employment of rural labor forces, and conducting cointegration test and Granger ... Taking Shouguang City in Shandong Province as an example, this article researches the mutual relationship between urban-rural income and employment of rural labor forces, and conducting cointegration test and Granger causality test on the variable sequences using statistical data. The results show that the average annual income of rural labor forces influences the income per capita of rural residents, and there is a Granger causality relationship between the income per capita of rural residents and urban employees' average wage. Engaging in production concerning agriculture, forestry, animal husbandry and fishery makes the total income per capita in rural areas of Shouguang City higher than the average wage of urban residents in Shouguang City, even in Weifang City. The comparative advantage in terms of income causes the city to loose attraction to rural residents in Shouguang City. The comparative advantage drives more rural labor forces in Shouguang City to engage in primary industry, thereby greatly reducing the pressure of employment and transfer of rural labor forces. Finally important following measures are put forward to promote employment and on-the-spot transfer of rural labor forces: vigorously propel agricultural industrialization; increase rural residents' income; improve the living conditions for rural residents. 展开更多
关键词 urban-rural INCOME gap RURAL LABOR FORCES GRANGER
在线阅读 下载PDF
GaP/SiH范德华异质结构的可调谐电子和光学特性的第一性原理研究
13
作者 郭鑫 马永强 +4 位作者 鲍爱达 邓蕊 秦丽 张文琦 徐厚敦 《高等学校化学学报》 北大核心 2025年第2期135-142,共8页
预测并构建了一种Ⅱ型的GaP/SiH异质结构,并对其结构特性、电子特性和光学特性进行了研究.结果表明,该GaP/SiH异质结构属于典型的Ⅱ型范德华异质结构,展现出卓越的能量稳定性.GaP/SiH异质结构的带隙为2.24 eV,Ⅱ型能带结构的排列有效抑... 预测并构建了一种Ⅱ型的GaP/SiH异质结构,并对其结构特性、电子特性和光学特性进行了研究.结果表明,该GaP/SiH异质结构属于典型的Ⅱ型范德华异质结构,展现出卓越的能量稳定性.GaP/SiH异质结构的带隙为2.24 eV,Ⅱ型能带结构的排列有效抑制了光生载流子的复合.通过施加不同的双轴应变和垂直应变,可以对异质结的电子结构进行一定范围内的精确调控.GaP/SiH异质结构在可见光和紫外光区也表现出优异的光吸收性能,吸收率可达2.34×10^(6)cm^(−1).GaP/SiH异质结构表现出的优异性能为光电子器件的设计提供了参考. 展开更多
关键词 第一性原理 gap/SiH范德华异质结构 光吸收
在线阅读 下载PDF
Spatial Distribution Pattern and Influencing Factors of Bed-and-breakfasts(B&Bs)from the Perspective of Urban-rural Differences:A Case Study of Jiaodong Peninsula,China 被引量:1
14
作者 WANG Xinyue MA Qian 《Chinese Geographical Science》 SCIE CSCD 2024年第4期752-763,共12页
There are significant differences between urban and rural bed-and-breakfasts(B&Bs)in terms of customer positioning,economic strength and spatial carrier.Accurately identifying the differences in spatial characteri... There are significant differences between urban and rural bed-and-breakfasts(B&Bs)in terms of customer positioning,economic strength and spatial carrier.Accurately identifying the differences in spatial characteristics and influencing factors of each type,is essential for creating urban and rural B&B agglomeration areas.This study used density-based spatial clustering of applications with noise(DBSCAN)and the multi-scale geographically weighted regression(MGWR)model to explore similarities and differences in the spatial distribution patterns and influencing factors for urban and rural B&Bs on the Jiaodong Peninsula of China from 2010 to 2022.The results showed that:1)both urban and rural B&Bs in Jiaodong Peninsula went through three stages:a slow start from 2010 to 2015,rapid development from 2015 to 2019,and hindered development from 2019 to 2022.However,urban B&Bs demonstrated a higher development speed and agglomeration intensity,leading to an increasingly evident trend of uneven development between the two sectors.2)The clustering scale of both urban and rural B&Bs continued to expand in terms of quantity and volume.Urban B&B clusters characterized by a limited number,but a higher likelihood of transitioning from low-level to high-level clusters.While the number of rural B&B clusters steadily increased over time,their clustering scale was comparatively lower than that of urban B&Bs,and they lacked the presence of high-level clustering.3)In terms of development direction,urban B&B clusters exhibited a relatively stable pattern and evolved into high-level clustering centers within the main urban areas.Conversely,rural B&Bs exhibited a more pronounced spatial diffusion effect,with clusters showing a trend of multi-center development along the coastline.4)Transport emerged as a common influencing factor for both urban and rural B&Bs,with the density of road network having the strongest explanatory power for their spatial distribution.In terms of differences,population agglomeration had a positive impact on the distribution of urban B&Bs and a negative effect on the distribution of rural B&Bs.Rural B&Bs clustering was more influenced by tourism resources compared with urban B&Bs,but increasing tourist stay duration remains an urgent issue to be addressed.The findings of this study could provide a more precise basis for government planning and management of urban and rural B&B agglomeration areas. 展开更多
关键词 urban-rural bed-and-breakfasts(B&Bs) spatiotemporal evolution density-based spatial clustering of applications with noise(DBSCAN)model multi-scale geographically weighted regression(MGWR) Jiaodong Peninsula China
在线阅读 下载PDF
Comparative Research on Prediction Model of China's Urban-rural Residents' Income Gap 被引量:2
15
作者 TU Xiong-ling School of Finance and Statistics,Jiangxi University of Finance and Economics,Nanchang 330013,China 《Asian Agricultural Research》 2011年第5期88-91,95,共5页
By using the data concerning China's urban-rural residents' income gap from 1978 to 2010,this paper mainly researches the application of several kinds of models in predicting China's urban-rural residents&... By using the data concerning China's urban-rural residents' income gap from 1978 to 2010,this paper mainly researches the application of several kinds of models in predicting China's urban-rural residents' income gap.By conducting empirical analysis,we establish ARIMA prediction model,grey prediction model and quadratic-polynomial prediction model and conduct accuracy comparison.The results show that quadratic-polynomial prediction model has excellent fitting effect.By using quadratic-polynomial prediction model,this paper conducts prediction on trend of China's urban-rural residents' income gap from 2011 to 2013,and the prediction value of income gap of urban-rural residents in China from 2011 to 2013 is 14 173.20,15 212.92 and 16 289.67 yuan respectively.Finally,on the basis of analysis,corresponding countermeasures are put forward,in order to provide scientific basis for energy planning and policy formulation:first,strengthen government's function of public service,coordinate resources,and strive to provide an equal opportunity of development for social members,so as to promote people's welfare and promote social equality;second,breach industrial monopoly and bridge income gap between employees in monopoly industry and general industry;last but not the least,support,encourage and call for government to establish social relief fund,adjust residents' income distribution from the non-governmental perspective,and endeavor to promote the income level of low-income class. 展开更多
关键词 urban-rural residents’ INCOME gap ARIMA model GREY
在线阅读 下载PDF
RAP1GAP基因多态性与阳原驴产仔数的相关分析
16
作者 陈亮 苏咏梅 +9 位作者 朱文进 李可强 李哲 明佳 逯春香 王茂森 胡文波 路长青 刘海洋 张艳英 《中国畜牧杂志》 北大核心 2025年第6期152-159,共8页
本试验旨在研究RAP1 GTP酶激活蛋白(Rap1 GTPase-activating Protein,RAP1GAP)基因多态性与阳原驴产仔数的相关性。以86头阳原驴母驴(其中10头为产双仔母驴)为研究对象,采用PCR-SSCP技术对RAP1GAP基因单核苷酸多态性(Single Nucleotide ... 本试验旨在研究RAP1 GTP酶激活蛋白(Rap1 GTPase-activating Protein,RAP1GAP)基因多态性与阳原驴产仔数的相关性。以86头阳原驴母驴(其中10头为产双仔母驴)为研究对象,采用PCR-SSCP技术对RAP1GAP基因单核苷酸多态性(Single Nucleotide Polymorphism,SNP)位点进行分型,并对各SNP位点与阳原驴产仔数进行关联分析。结果表明:在RAP1GAP基因中发现8个单碱基突变,分别为g.44031G>C、g.44156G>C、g.48851 A>G、g.49456 A>C、g.52853T>C、g.52880T>C、g.59730T>C、g.64393T>G。其中g.44031 G>C在外显子上且为错义突变,导致蛋白质二级结构发生变化,其余7个位点均在内含子上。g.44031G>C、g.44156G>C位点CG和GG基因型个体的平均产仔数显著高于CC基因型;g.49456 A>C位点AC基因型个体的平均产仔数显著高于CC和AA基因型;g.52853 T>C、g.52880 T>C位点CT和TT基因型个体的平均产仔数显著高于CC基因型;g.59730 T>C位点CC基因型个体的平均产仔数显著高于CT和TT基因型;而g.48851 A>G、g.64393 T>G位点未发现与产仔数存在显著关联性。综上,RAP1GAP基因的g.44031G>C、g.44156 G>C、g.49456 A>C、g.52853 T>C、g.52880 T>C、g.59730 T>C 6个位点可作为阳原驴产仔数育种的分子标记。 展开更多
关键词 阳原驴 RAP1gap 多态性 产仔数
在线阅读 下载PDF
The Impact of the Upgrading of Industrial Structure in the Yangtze River Delta on the Urban-Rural Income Gap 被引量:1
17
作者 Qianqian Zhao 《管理科学与研究(中英文版)》 2021年第1期7-16,共10页
Firstly,this paper conducts theoretical analysis and current situation analysis,and then proposes research hypotheses.Secondly,using spatial Dubin model and partial differential method,it empirically studies the impac... Firstly,this paper conducts theoretical analysis and current situation analysis,and then proposes research hypotheses.Secondly,using spatial Dubin model and partial differential method,it empirically studies the impact of industrial structure advancement and rationalization on the urban-rural income gap.The results show that:(1)Both industrial structure and urban-rural income gap have significant spatial dependence;(2)The increase in the industrial structure rationalization will narrow the urban-rural income gap in local region,while its spillover effect on neighboring areas is not obvious.(3)The impact of the industrial structure advancement on the urban-rural income gap is not linear.It is first expanded and then narrowed.The industrial structure advancement in the Yangtze River Delta will generally narrow the urban-rural income gap at this stage.Finally,this paper put forward relevant suggestions. 展开更多
关键词 Yangtze River Delta(Yrd) urban-rural Income gap Upgrading of Industrial Structure Spatial Dubin Model
在线阅读 下载PDF
高承载下Al_(2)O_(3)-GdAlO_(3)(GAP)非晶陶瓷涂层的摩擦磨损性能
18
作者 艾伊昭彤 任九龙 +3 位作者 强林芽 张小珍 杨凯 高彦峰 《无机材料学报》 北大核心 2025年第10期1111-1118,共8页
针对高承载、高温、富氧及宽温域交变热冲击等苛刻工况的航空航天动力装置关键部件,对材料的力学性能、热稳定性及抗氧化能力提出了极高要求。传统热喷涂技术制备的Al_(2)O_(3)涂层凭借高硬度、良好的耐磨性、优异的抗氧化能力及较好的... 针对高承载、高温、富氧及宽温域交变热冲击等苛刻工况的航空航天动力装置关键部件,对材料的力学性能、热稳定性及抗氧化能力提出了极高要求。传统热喷涂技术制备的Al_(2)O_(3)涂层凭借高硬度、良好的耐磨性、优异的抗氧化能力及较好的热稳定性,已在航空航天、能源及机械等领域得到了广泛应用。然而,热喷涂Al_(2)O_(3)涂层以亚稳态γ-Al_(2)O_(3)为主晶相,力学及导热性能弱于α-Al_(2)O_(3)相,这限制了其在更高承载极端工况下的应用效果。为解决上述问题并提升涂层的综合性能,本研究采用大气等离子体喷涂(Atmospheric Plasma Spraying,APS)技术,制备了厚度约350μm的Al_(2)O_(3)-GdAlO_(3)(GAP)非晶涂层。通过设计磨损试验(载荷2000 N、转速500 r/min、时间1 h),对涂层的摩擦磨损行为及力学性能进行了系统考察。实验结果表明,由于涂层中高比例的非晶相及优化的微观结构,Al_(2)O_(3)-GAP涂层在高速重载摩擦测试中表现出优异的耐磨性和抗裂纹扩展能力,显著优于传统多晶Al_(2)O_(3)涂层。此外,Al_(2)O_(3)-GAP涂层的摩擦系数较低且稳定,摩擦表面温度明显降低,减缓了高温氧化及热损伤的发生,缓解了应力集中效应。综上所述,Al_(2)O_(3)-GAP非晶涂层在高载荷、高速摩擦工况下具有显著优势,为航空航天动力装置关键部件的防护提供了一种高性能、可靠服役的涂层解决方案。 展开更多
关键词 大气等离子体喷涂 Al_(2)O_(3)-GdAlO_(3)(gap) 非晶陶瓷涂层 高承载耐磨性能
在线阅读 下载PDF
甜瓜基因组GAPs特征及形成原因探究
19
作者 王孟文 王贤磊 +1 位作者 彭媛 李泽玉 《新疆大学学报(自然科学版中英文)》 2025年第1期66-72,共7页
未知区域(GAPs)是基因组中未被测序或组装的区域.经单分子三代测序,甜瓜基因组中GAPs由基因组V3.6.1中的79.68 Mb减少至基因组V4.0中的0.12 Mb.以甜瓜基因组V3.6.1和V4.0数据为研究对象,获取并分析基因组中GAPs内部及侧翼序列特征及规律... 未知区域(GAPs)是基因组中未被测序或组装的区域.经单分子三代测序,甜瓜基因组中GAPs由基因组V3.6.1中的79.68 Mb减少至基因组V4.0中的0.12 Mb.以甜瓜基因组V3.6.1和V4.0数据为研究对象,获取并分析基因组中GAPs内部及侧翼序列特征及规律,并探究GAPs形成原因,为组装高质量甜瓜基因组提供参考.结果表明:与基因组整体相比,GAPs内部两侧150 bp区域,简单重复序列(Simple Sequence Repeats,SSR)密度较高、非SSR区域GC含量较高,GAPs外侧150 bp含有较高的多拷贝序列.较高GC含量和微卫星密度会影响PCR扩增,多拷贝序列的存在会影响下游序列的拼接组装,且在GAPs两侧150 bp与GAPs全序列比较发现,越临近GAPs边界,其GC含量与微卫星密度越高.认为甜瓜基因组V3.6.1中GAPs形成的主要原因是含有较高GC含量、微卫星密度及较多的多拷贝序列;对V4.0基因组GAPs两侧序列比对分析发现,多拷贝序列占比为98.24%,多拷贝序列可能是V4.0中GAPs形成的重要原因. 展开更多
关键词 甜瓜 基因组 重复序列 SSR gapS
在线阅读 下载PDF
硝酸酯增塑GAP黏合剂与N100固化反应动力学的近红外光谱法研究
20
作者 张玉樊 徐胜良 +1 位作者 黄志萍 聂海英 《固体火箭技术》 北大核心 2025年第1期102-107,共6页
为监测硝酸酯增塑聚叠氮缩水甘油醚(GAP)/多异氰酸酯(N100)体系的固化反应动力学过程,基于近红外光谱技术提出了推进剂固化反应监控方法。采用多元曲线分辨-交替最小二乘(MCR-ALS)法,从连续采集的固化过程近红外光谱中提取了固化组分浓... 为监测硝酸酯增塑聚叠氮缩水甘油醚(GAP)/多异氰酸酯(N100)体系的固化反应动力学过程,基于近红外光谱技术提出了推进剂固化反应监控方法。采用多元曲线分辨-交替最小二乘(MCR-ALS)法,从连续采集的固化过程近红外光谱中提取了固化组分浓度随时间的变化曲线,通过相似度评价验证了该方法的准确性,并建立了硝酸酯增塑GAP黏合剂与N100的固化反应动力学模型。结果表明,采用连续小波变换结合MCR-ALS分析固化过程近红外光谱,方法相似度大于99%,可以提取固化反应过程中的组分浓度曲线和光谱曲线,为GAP固化反应分析提供了一种快速无损的在线监测方法;GAP黏合剂/N100体系固化反应在反应前中期遵循一级动力学反应,表观活化能为84.46 kJ/mol;反应后期,机理函数变为二维扩散模型,表观活化能为66.09 kJ/mol。 展开更多
关键词 近红外光谱 硝酸酯增塑gap黏合剂 固化反应动力学 多元曲线分辨-交替最小二乘法
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部