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41.
It is important to quantitatively analyze the effects of protection of important eco-logical spaces in China to ensure national ecological security.By considering changes in the ecological land,this study examines the effects of protecting three types of important natural ecological spaces in China from 1980 to 2018.Moreover,considering important ecological spaces and their surroundings yields differences in the effects of protection between internal and external spaces,where this can provide a scientific basis for the categorization and zoning of China's land.The results show the following:(1)In 2018,the ratio of ecological land to important natural ecological spaces accounted for 92.64%.This land had a good ecological background that reflects the developmental orientation of important ecological spaces.(2)From 1980 to 2018,the area of ecological land in important ecological spaces shrank but the rate of reduction was lower than the national average,which shows the positive effect of regulating construction in natural ecological spaces.The restorative effects of ecological projects to convert farmland into forests and grasslands have been prominent.The expanded ecological land is mainly distributed in areas where such projects have been implemented,and the reduced area is concentrated in grain-producing areas of the Northeast China Plain and agricultural oases of Xinjiang.In the future,the government should focus on strength-ening the management and control of these areas.(3)The area ratio of ecological land was the highest in national nature reserves.The rate of reduction in its area was the lowest and the trend of reduction was the smallest in national nature reserves,which reflects differences in the status of ecological protection among different spaces.(4)The ratio of ecological land to important ecological spaces was higher than that in the surrounding external space,and the rate of reduction in it was lower.Thus,the effects of internal and external protection had clear differences in terms of gradient.  相似文献   
42.
基于实验与计算相结合的方法,在实验室配制标准物质去检测全新的FDR型土壤水分传感器,得出被测值;利用烘干称重法测量标准物质的容积含水量,得出标准值。使用数学方法分析检验两者之间的误差,验证贵州省气象部门FDR型土壤水分传感器校准方法的可行性。结果显示:误差在(-2.5%~2.5%)的传感器占总传感器的99.4%;误差在(-2%~2%)的传感器占总传感器的97.5%;在99.7%的置信区域内,所有校准点的标准差都小于5%。结合工作实际检验,该校准方法可应用于贵州省土壤水分传感器校准。  相似文献   
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我国在海域开展了大规模的航空重力勘探,这些资料对构建高精度大地水准面具有重要价值.基于此,本文提出一种利用海域航空重力测量数据快速构建大地水准面的方法.该方法基于移去-恢复法思想,利用位场最小曲率方法对航空重力数据进行高精度向下延拓并获取相应的扰动位,实现航空重力测量快速构建海域大地水准面.与斯托克斯积分计算相比,采用了处理效率更高的频率域位场转换,解决了向下延拓及垂向积分时航空重力异常数据空白及扩边问题,具有较高的位场转换精度.本文应用EGM2008模拟航空重力数据进行模型验证,计算结果与其给出的水准面的精度相当;同时,也选取GRAV-D计划的航空重力数据进行实际验证,计算结果与xGEOID18B水准面模型精度基本一致.模型验证和实际应用验证了本方法的实用性.  相似文献   
45.
In this paper, we consider the time at which earthquake events occur when analyzing seismic structural damage to a deteriorating RC bridge within a specified period. Because the uncertainty exists in the occurrence time of earthquake events, Monte Carlo simulation is applied. The proposed procedure for evaluating the exceedance probability, which corresponds to a specified limit state, is then applied to a case study of RC bridges in Taiwan to demonstrate its applicability. This study selects three typical RC bridges located in the Taipei Basin, Taiwan, to analyze exceedance probabilities of specified damage states during various specified periods and then discusses the cumulative damage effect on the exceedance probabilities of specified damage states. Additionally, for the chloride-induced deteriorating bridges at various distances to the sea in Suao, Taiwan, the effects of the deterioration and seismic structural damage on the exceedance probabilities of specified damage states are demonstrated and discussed. The proposed assessment procedure can help engineers understand whether the deterioration would accelerate the declining seismic performance of bridges and shorten their serviceability-related and safety-related service lives, as well as provide reference for repairing RC bridges and retrofitting their seismic performance.  相似文献   
46.
吕拉昌  于英杰  栾惠 《地理科学》2022,42(1):115-125
城市舒适性对城市创新发展有重要影响,但对大都市区内部舒适性及差异性对城市创新能力的影响研究较少。以北京市为研究区域,利用耦合协调度模型和多元线性回归模型分析城市舒适性与创新能力的关系。研究发现:① 北京市总体舒适性分布特点是以中心城区为核心,随着距中心城区距离增加,城区的舒适性水平逐渐降低。② 北京生态环境舒适性呈现从西北地区向东南地区逐渐递减的特点,而人工环境和社会氛围的舒适性由中心向四周地区递减,各区的舒适性水平在空间分布上呈集聚状态,高-高型聚类集中在东城区、西城区、朝阳区、海淀区及丰台区,形成北京市“高舒适性”区域。③ 结合耦合协调度模型发现北京市除平谷区、密云区和延庆区,其他城区目前均处于高水平耦合阶段,海淀区、东城区、西城区、朝阳区、丰台区的创新能力和舒适性发展耦合协调度较高,但北京市各区也存在舒适性与城市创新之间发展相对滞后问题。④ 北京城市舒适性与创新能力存在正相关关系,但不同舒适性要素对创新能力的作用不同,文化教育条件对城市创新能力的影响强度最大,交通便利性和社会氛围对创新能力的作用次之。政策建议是要推进文化教育、交通条件等人工舒适性水平的相对均衡发展,提高各区的城市舒适性,以城市舒适性推动创新能力的提升。  相似文献   
47.
姚作新  秦荣茂  任泉  吕鸣  何芳 《气象科技》2013,41(5):949-954
新疆气象局依据中国气象局发布的《霾的观测和预报等级》(QX/T113-2010)中霾观测等级标准,开发的“雾霾天气自动判识业务系统”软件,具备自动识别雾、霾、晴等天气现象的功能,能24 h连续在线、实时、自动显示气象监测站PM2.5、气溶胶吸收特性等表征大气洁净状况的监测值,能为气象站观测员提供一个辅助判识雾、霾等天气状况的依据,能为预报员提供一个检验雾、霾等天气状况预报质量的在线实况依据.该软件系统已经在乌鲁木齐国家基本气象站、自治区气象台等单位试运行,且运行情况良好.  相似文献   
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49.
中国战略性新兴产业集聚度演变与空间布局构想   总被引:1,自引:0,他引:1  
培育和发展战略性新兴产业,重要任务之一是建成一批产业链完善、创新能力强、特色鲜明的战略性新兴产业集聚区.依据国家统计局编制的《战略性新兴产业分类》(试行),选取了18个战略性新兴产业大类行业,运用地理集中指数方法对中国战略性新兴产业的集聚程度及演变趋势进行分析,并进一步考察其区域分布特征,进而根据测算结论提出中国西部地区战略性新兴产业的布局应以点状模式为主、中部地区应以点轴模式为主、东部沿海地区应以网络模式为主的空间布局模式构想,以及中国战略新兴产业“一带、两区、多点”的空间布局方案构想,以期为中国战略性新兴产业现阶段所面临的区域间同质化竞争和低水平重复建设问题提供突围良策.  相似文献   
50.
Utilizing experimental data of the atmospheric surface layer in the Gobi Oasis of Jinta in a comparative study, we demonstrate that under the condition of unstable stratification, the normalization variances of temperature in the oasis and Gobi Desert meet 1/3(z/Λ)(z/Λ)while normalization variances of both humidity and CO2 in the oasis meet(z)sz\Λ-1/3;s s z Λ the normalization variance of temperature in the oasis is large due to disturbance by advection, whereas variance of CO2 in the Gobi Desert has certain degree of deviation relative to Monin-Obukhov(M-O) scaling, and humidity variance completely deviates from variance M-O scaling. The above result indicates that under the condition of advection, humidity variance meets the relationsm sA sB D and it is determined by relative magnitude of scalar variance of advection transport. Our study reveals that, if the scalar variance of humidity or CO2 transported by advection is much larger than local scalar variance, observation value of scalar variance will deviate from M-O scaling; when scalar variance of advection transport is close to or less than local scalar variance, the observation value of scalar variance approximately meets M-O scaling.  相似文献   
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