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基于GIS的宁夏压沙地生产力评价研究 被引量:4
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作者 王宾 田军仓 《节水灌溉》 北大核心 2012年第8期69-73,共5页
宁夏中西部干旱地带,气候干旱,水资源匮乏,通过对压沙地生产力自然条件评价和社会经济指标评价综合评价压沙地的生产力,得出宁夏中卫压沙地评价区的综合评价指数SI模型,即SI=0.8PI+0.2TI。其中自然生产力的评价从土壤化学条件、土壤物... 宁夏中西部干旱地带,气候干旱,水资源匮乏,通过对压沙地生产力自然条件评价和社会经济指标评价综合评价压沙地的生产力,得出宁夏中卫压沙地评价区的综合评价指数SI模型,即SI=0.8PI+0.2TI。其中自然生产力的评价从土壤化学条件、土壤物理条件、土壤生态条件3方面,应用FAO提出的PI模型进行评价;社会经济条件评价从压沙地年限、水利化水平、化学化水平、农业机械化水平和耕地现有人口承载量5个方面,应用层次分析法,得出各个指标的影响权重,最后应用TI模型进行评价。 展开更多
关键词 压沙地 生产力 评价模型 评价指标
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宁夏压沙地西瓜自然降水生产力及障碍因子分析 被引量:2
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作者 赵小勇 田军仓 《节水灌溉》 北大核心 2012年第5期16-18,共3页
在水资源缺乏状况下,通过降水模拟对比试验,分析宁夏各压沙地类型在不同自然降水水平下的生产力及主要障碍因子对产量影响度。研究表明,西瓜自然降水生产力大小排序依次为丰水年>平水年>枯水年,新沙地>中沙地>老沙地;障碍... 在水资源缺乏状况下,通过降水模拟对比试验,分析宁夏各压沙地类型在不同自然降水水平下的生产力及主要障碍因子对产量影响度。研究表明,西瓜自然降水生产力大小排序依次为丰水年>平水年>枯水年,新沙地>中沙地>老沙地;障碍因子影响程度为水文条件>压沙类型>肥力水平,为当地压沙地西瓜生产提供科学指导依据。 展开更多
关键词 压沙地 自然降水生产力 障碍因子
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自然降雨条件下不同种植模式土面蒸发规律研究 被引量:1
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作者 李王成 刘民安 +2 位作者 王帅 刘学智 董亚萍 《湖北农业科学》 2017年第23期4507-4509,共3页
在自然降雨条件下,对西瓜不同种植模式的土壤水分运动及土面蒸发规律进行研究。结果表明,不同种植方式的土壤水分在0~100 cm的土层内,土壤含水率随时间的变化幅度较大,在100 cm以下的土层所受影响较小,各处理动态储水量变化范围为0~100... 在自然降雨条件下,对西瓜不同种植模式的土壤水分运动及土面蒸发规律进行研究。结果表明,不同种植方式的土壤水分在0~100 cm的土层内,土壤含水率随时间的变化幅度较大,在100 cm以下的土层所受影响较小,各处理动态储水量变化范围为0~100 cm。在降雨后的2 d内裸地的蒸发量与水面蒸发量接近一致,日蒸发量可达到9.3 mm,2 d后,土面蒸发量从9.3 mm减小至0.3 mm,在没有降雨补给的情况下,土面蒸发量无限接近于0,而压沙地的土面蒸发则始终维持在1.1 mm左右;总体上,水面日平均蒸发量为9.3 mm,裸地土面日平均蒸发量为1.8 mm,压沙地土面日平均蒸发量为1.1 mm。 展开更多
关键词 土面蒸发量 覆盖 压沙地 水分运动
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Effect of amlodipine combined with telmisartan or compound amiloride on plasma ET-1 concentration and left ventricular diastolic function of essential hypertension patients with left ventricular hypertrophy 被引量:2
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作者 YIN Yanrong WANG Xin +2 位作者 WANG Yaping ZHANG Yong TIAN Gang 《Journal of Medical Colleges of PLA(China)》 CAS 2013年第6期345-354,共10页
Objective: To observe the effect of different combination antihypertensive therapies on plasma endothelin-1 (ET-1) concentration and left ventricular diastolic function of essential hypertension patients with left ... Objective: To observe the effect of different combination antihypertensive therapies on plasma endothelin-1 (ET-1) concentration and left ventricular diastolic function of essential hypertension patients with left ventricular hypertrophy (LVH) Methods: A total of 111 patients with essential hypertension were selected, including 60 cases (34 males, 26 females) aged (60.7±5.6) years with simple hypertension, and 51 cases (28 males, 23 females) aged (61.8±7.0) years with essential hypertension complicated with LVH. Essential hypertension patients with LVH were randomly divided into the group of amlodipine (2.5 mg/d) combined with telmisartan (40 mg/d, n=26) and the group of amlodipine (2.5 mg/d) combined with amiloride (half tablet/d, n=25),and the treatment lasted for 1 year. Echocardiography was performed before and after the treatment. Left ventricular mass index (LVMI), left ventricular isovolumic relaxation time (IVRT) and other indicators were detected, and plasma ET-1 concentrations were measured for comparative analysis. And 56 patients (31 males, 25 females) aged (59.3±6.7) years with normal blood pressure in the same period in our hospital were selected as the normal control group. Results: The general clinical characteristics were similar between hypertensive LVH group, simple hypertensive group and normal healthy control group. Plasma ET-1 concentrations, LVMI and IVRT of hypertensive LVH group were significantly higher than those of normal control group and simple hypertension group, and the difference was statistically significant. The patients' baseline blood pressure, ET-1, LVMI, interventricular septal thickness (IVST), left ventricular posterior wall thickness (LVPWT), left ventricular end-diastolic diameter (LVEDd) and other clinical parameters showed no significant difference (P〉0.05) between the group of amlodipine combined with telmisartan and the group of amlodipine combined with amiloride. It was found that compared with that before treatment, blood pressure could be effectively controlled (P〈0.05), and LVMI, IVST, LVPWT and IVRT (P〈0.05) were all lowered, and ET-1 (P〈0.01) was significantly reduced after 1 year of antihypertensive therapy in both the group of amlodipine combined with telmisartan and the group of amlodipine combined with amiloride. The group of amlodipine combined with telmisartan was better in lowering blood pressure and reducing LVMI, IVST, LVPWT, IVRT and ET-1 than the group of amlodipine combined with amiloride (P〈0.05). Conelus|on: Amlodipine-based combination antthypertensive therapy could reverse LVH and improve left ventricular diastolic function partly by lowering blood pressure and ET-1, and the effect of amlodipine combined with telmisartan was superior to that ofamlodipine combined with amiloride 展开更多
关键词 HYPERTENSION Left ventricular hypertrophy ENDOTHELIN-1 Left ventricular diastolic function
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Influence of Lithological Characters of Coal Bearing Formation on Stability of Roof of Coal Seams
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作者 孟召平 彭苏萍 +3 位作者 李国庆 黄为 芦俊 雷志勇 《Journal of China University of Mining and Technology》 2003年第1期1-6,共6页
Lithology is one of the important factors influencing the stability of roof of coal seams. In order to investigate this, the phenomenon of underground pressure and distribution of pressure were studied by using the lo... Lithology is one of the important factors influencing the stability of roof of coal seams. In order to investigate this, the phenomenon of underground pressure and distribution of pressure were studied by using the local observation and simulation test with similar materials. The observation results show that the distance of initial weighting and periodic weighting of the mudstone roof is shorter than that of sandstone roofs. The sandstone roof with a high strength has a longer distance of initial weighting and periodic weighting, the abutment stress on the working face is big and the height of caving and fracture zone is high. The peak point of abutment stress in the sandstone roof is near to the working face and the pressure bump is inclined to occur. The result is contrary to that in case of the mudstone roof with a low strength. While in the transition zone of nipped sandstone, roof rock-mass is broken and is poor in stability, therefore, it is difficult to hold the roof. 展开更多
关键词 Coal bearing formation lithological characters roof stability
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沙地枣树冬季管理技术
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作者 李春松 《北京农业(下旬刊)》 2013年第A04期35-35,共1页
宁夏中卫市地处中部干旱带,近年来,压沙西瓜的种植已经成为本地区农民发家致富的重要途径。目前,中卫市压沙地面积已经达到近6.67万hm2。大量推广枣瓜间作的种植模式是很有必要的。
关键词 压沙地 枣树 冬季管理
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