中国八个地区的消费需求分析   总被引：12，自引：1，他引：11  

钟颖杰  王铮 《地理学报》1998,53(4):295-302

本文应用经济学的消费需求分析模式,分析了我国８个代表地区的消费需求特性,并讨论了其对可持续发展的意义。  相似文献   

长白山地区近代火山岩的ESR测年研究   总被引：3，自引：0，他引：3  

尹功明  业渝光  万京林  孙瑛杰  陈文寄  刁少波 《地质论评》1999,45(7):287-293

在对火山灾害和潜在危险性评价中火山活动的时代起着极其重要的作用,但是,目前还没有成熟的测年方法能够对年轻火山岩直接定年。本文采用电子自旋共振（ESR）测年方法对年轻火山岩直接测年进行了尝试。所测年轻火山岩石英矿物中没有E信号,有较弱的Ge中心信号,根据Ge中心信号获得了长白山三期近代火山岩的年龄,其中,气象站碱性流纹岩的ESR年龄约3930 a BP,而气象站碱性流纹岩之下粗面岩的ESR年龄约为17500～20900 a BP。  相似文献   

湖北省水库与湖泊银鱼移植与增殖试验   总被引：2，自引：0，他引：2  

龚世园  张训蒲  何绪刚  杨学芬  梁开学  刘英杰  严国璋  王晓燕 《湖泊科学》2004,16(2):186-191

在受试水库、湖泊中,移植与增殖二种银鱼,即近太湖新银鱼和太湖新银鱼。经三种人工采卵受精技术的比较试验,采用半干法人工受精最为理想。经多种受精卵运输方法的比较试验,采用塑料袋充氧运输最为理想。经散撒受精卵和网箱孵化的比较实验,采用网箱孵化最为理想。经不同放流鱼苗技术的比较实验,采用鱼苗平游后放流最为理想。经不同季节、不同开捕时间的比较实验,二种银鱼的合理捕捞时间为秋冬季,严禁在春季捕捞;最合理的开捕时间为国庆节前后。近太湖新银鱼和太湖新银鱼的人工采卵授精时间为3月上旬和4月上旬,严禁在非繁殖盛期采卵。银鱼的捕捞强度应控制在资源量的2/3或3/4范围内。  相似文献   

基于主客观赋权模糊综合评价法的湖泊水生态系统健康评价   总被引：2，自引：0，他引：2  

吴易雯  李莹杰  张列宇  过龙根  李华  席北斗  王雷  李曹乐 《湖泊科学》2017,29(5):1091-1102

运用湖泊营养状态指数判断湖泊的富营养化状态,并根据湖泊的水质、沉积物和水生生物群落的现状和特点,运用主观赋权法中的层次分析法和客观赋权法中的熵权法结合模糊综合评价法,对长江中游地区江汉湖群37个湖泊的水生态系统进行健康状态评价.对湖泊富营养化的调查结果表明,海口湖处于中营养状态,18个湖泊处于富营养化状态,18个湖泊处于超富营养化状态.湖泊生态系统健康评价的研究结果表明,37个湖泊中,处于健康状况"优"的湖泊只有海口湖,处于健康状况"良"的湖泊有5个,分别为东西汊湖、花马湖、梁子湖、童家湖和涨渡湖,其余31个湖泊均处于健康状况"差"的状态.经过与湖泊营养状态指数的对照,本研究结果表明,由主观赋权的专家评分的层次分析法结合模糊综合评价法对江汉湖群湖泊水生态健康状态的评价效果相比客观赋权的熵权模糊综合评价法更贴合实际.  相似文献   

喀斯特湿地水葫芦(Eichhornia crassipes)生长及表型可塑性特征对不同富营养化水体的响应   总被引：1，自引：0，他引：1  

滕秋梅  孙英杰  沈育伊  张德楠  徐广平  周龙武  张中峰  黄科朝  何文  何成新 《湖泊科学》2021,33(1):123-137

选择桂林会仙喀斯特湿地,以不同富营养化水体中生长时期为6月(生长旺盛期)和8月(暴发高峰期)的水葫芦(Eichhornia crassipes)为研究对象,探讨不同富营养化条件下水葫芦的生长及表型可塑性响应特征,以揭示水葫芦对不同富营养化水体的生态适应机制.结果表明:水葫芦的株高、根长和叶绿素含量均随水体富营养化程度的增加而降低,叶柄数、叶柄宽、叶片数、叶长、叶宽、匍匐茎数和分株速率随着水体富营养化程度的增加而升高;各性状参数在暴发高峰期均略高于生长旺盛期;根生物量、茎生物量、叶生物量和总生物量均随水体富营养化程度的加深而增加,茎生物量高于根生物量和叶生物量;水葫芦生物量的分配以及性状间的权衡关系(根生物量比、茎生物量比、叶生物量比和茎叶比等)因生长时期的不同而呈现差异性,表现出较强的表型可塑性特征;水体总有机碳、总氮、总磷、硝态氮、氨氮和叶绿素a浓度分别与水葫芦的茎生物量、叶宽、匍匐茎数和分株速率间存在显著的正相关关系,与根长、株高、叶生物量比和茎叶比间存在显著的负相关关系;水葫芦的表型可塑性指数在0.009~0.792之间,叶重比的可塑性指数最大,根冠比最小,重度富营养化水体下的可塑性指数最大.在会仙喀斯特湿地不同富营养化水体环境中,水葫芦通过外部形态结构调节和生物量的配比关系,产生了有利于其入侵和存活的较强的表型可塑性,是其生存繁殖的重要响应机制之一.  相似文献   

涉县地磁台地磁观测室建设材料磁性检测     

李晓鹏  张小涛  江永建  赵长红  张英杰 《地震地磁观测与研究》2017,38(2):89-93

涉县地磁基准台地磁观测室在建设过程中严格按照观测规范要求施工,利用GSM-19T磁力仪,对建筑材料磁性进行严格检测和筛选,并对地磁房建设前后磁场梯度进行检测,对比可以发现磁房场地磁场梯度是否符合规范要求。此次涉县地磁房建设过程中各种建筑材料的磁性检测工作,可以为其他台站磁台建设提供参考。  相似文献   

Response of First-Order Sequence to the Galactic Year Cycle in the Phanerozoic:An Important Progress and Topic     

Yingjie Zhang  Long Wang 《地球科学进展》2020,35(3):275-285

The sequence which corresponds to the first-order sea-level cycle is called the first-order sequence, and the first-order sequence may have an internal relationship with the galactic year cycle, in other words, the galactic year cycle may control the first-order sequence macroscopically. The superevents in the Phanerozoic, such as the concentration change of atmospheric gas carbon dioxide, the alternation of "calcite sea" and "aragonite sea" in the hydrosphere, and the reversal of magnetic poles, are cyclical. They have obvious correlation in genesis, and they are likely to be controlled by the complicated genetic relationship between galactic annual cycles and various superevents. Over the years, researches have shown that when the solar system moves around the galactic center, the acceleration of gravity (value of G) changes accordingly, and the solar system expands (or shrinks). The Earth, a member of the solar system, forms a change in potential energy and absorbs (or releases) heat. At the same time, the gravitational differentiation changes as a result of the value of G change, which leads to the expansion of the mantle and the contraction of the core; when the energy accumulates to a certain degree, the superplume will be activated, which will affect the plate pattern on the earth. In recent years, the periodic changes of these superevents in Phanerozoic have attracted extensive attention and discussion. Paying attention to these wise understandings and existing problems will provide important thinking process and research clues for in-depth research.  相似文献   

西江梧州段水沙变化及原因分析     

朱颖洁 《水文》2017,37(5):84-91

分析了西江大湟江口-梧州段水沙组成,并采用不均匀系数分析其年内变化;通过相关分析研究降水与年径流量及年输沙量的关系;利用双累积曲线分析人类活动对水沙的影响;利用Morlet小波对梧州站年径流量及年输沙量进行突变分析;采用水文分析法量化降水与人类活动对水沙变化的影响。结果表明:2006年长洲水利枢纽正式运行导致地区水沙分布发生明显变化;年径流量和年输沙量年内分配具有一定的不均匀性;气候因素的变化只是西江年径流量和年输沙量变化的主要原因之一;在不受降水变化影响的情况下,西江年输沙量的变化,主要是人类活动影响流域侵蚀产沙的结果。  相似文献   

Evaluation of ontological value of regional tourism resources:A case study of Hainan Island,China     

ZHANG Tongyan  WANG Yingjie  ZHANG Shengrui  WANG Yingying  YU Hu 《地理学报(英文版)》2021,31(7):1015-1038

Evaluation of tourism resources is necessary for tourism regionalization and plan-ning and for the development of tourism destinations.Furthermore,the scientific evaluation of the status of existing tourism resources is important for optimally combining and rationally developing regional tourism resources.In this study,a conceptual model for estimating the ontological value of tourism resources was developed and an evaluation indicator system was designed for the ontological value.On the basis of the quantitative and spatial characteristics of regional tourism resources,six indicators were constructed:quantitative density,richness,dominance,combination,aggregation,and accessibility.Furthermore,spatial differentiation characteristics of the ontological value indicators of county-level tourism resources on Hainan Island were analyzed,and the ontological value of the tourism resources was comprehen-sively evaluated and ranked by using a fuzzy clustering evaluation method.Finally,the evaluation results were verified on the basis of the quantity,quality,and accessibility of re-gional tourism resources by using an expert scoring method.The results showed that the test results were consistent with the inferences drawn from the ontological value,indicating that the evaluation indicator system is scientific and reliable and that it is an effective alternative to existing evaluation indexes of regional tourism resources,which are inconsistent.The fuzzy clustering evaluation method overcomes the subjectivity in the evaluation process and is practical for the quantitative evaluation of regional tourism resources.The evaluation indicator system for regional tourism resources designed in this study can provide a reference for the evaluation of the tourism resource development value on a regional scale,and the evaluation results can facilitate informed policymaking for the rational development of regional tourism resources.  相似文献   

内蒙古西乌旗晚石炭世马尼塔埃达克岩的发现及其对古亚洲洋东段洋内俯冲的约束     

王帅  李英杰  王金芳  董培培  李红阳  郭雷亮  汪轩辰 《地质通报》2021,(1):82-94

在内蒙古西乌旗迪彦庙SSZ型蛇绿岩北部新发现一套晚石炭世马尼塔埃达克岩.该埃达克岩位于兴蒙造山带东段贺根山缝合带内,岩性为花岗闪长岩和斜长花岗岩.马尼塔埃达克岩SiO2含量为61.91％ ～75.16％,A12 O3含量为13.54％ ～17.42％,MgO含量为0.33％～2.49％,富钠贫钾(Na2O=4.58％～...  相似文献