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中国近年寒区地下水试验研究进展 总被引:1,自引:0,他引:1
占国土面积一半左右的寒区是中国重要的地理区域之一,由于特殊的低温环境,使得在寒区开展地下水赋存、运动和演化研究的过程中,比较倚重于试验基础。梳理分析可见,有关寒区地下水的试验研究可以大致归结为如下四类。①冻融过程中土壤水热盐迁移试验,这类试验数量最多,试验的目标内容在于监测、探究不同覆被/不同土质/不同冻融过程条件下土壤非饱和带水/热/盐单项或耦合迁移特征及其定量描述方法;②冻土水理性质试验,这类试验多结合寒区工程展开,其目的在于探究固/液二相不同组成条件下冻土的冻融特征参数与其工程力学性质的关系;③在东北、西北、青藏高原等寒区开展的具有显著地域特征和明确目标指向的应用类试验,主要针对各自区域的典型问题展开;④有关试验仪器、试验方法的研究。进一步梳理可知,中科院寒旱所和《冰川冻土》是国内支撑和交流寒区地下水试验研究的最重要的平台。 相似文献
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本文通过人工模拟气候下的冷冻实验,以生活污水为研究对象,分析冷冻法对水中有机物和NH3-N的去除效果。实验结果表明:冷冻法能有效的去除水中的污染物,对COD去除效率达到80%左右,对NH3-N去除效率达到90%左右。本方法所需设备简单、操作简便、高效低耗,特别适合我国北方冬季长、气温低的气候条件。 相似文献
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海冰在其成冰过程中盐分大量析出而盐度较低,可能成为干旱季节的一种灌溉水资源。海冰水改良滨海盐渍土是在渤海湾地区利用海冰融解的低盐水灌溉和淋洗高盐土壤的一种措施,该措施应用的同时也产生土壤熟化时间慢、土壤结构恶化、土壤养分的流失和土壤生物种群数量减少等问题。本文在收集和分析大量资料基础上,论述了蚯蚓与盐渍土壤的相互关系:盐碱地土壤中蚯蚓种类和盐渍土壤对蚯蚓的影响因素。根据在盐渍土壤中,蚯蚓活动能够增加有机物的分解和养分释放,同时使盐碱地土壤的团聚体结构、渗透率、生物数量和活性得以恢复和改善,进一步阐述了在海冰水改良滨海盐渍土壤中引入蚯蚓的可行性,并探讨引入蚯蚓改良滨海盐渍土壤的研究方法和存在的问题以及今后的研究方向。 相似文献
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Sheshadri Narayanan 《Indian journal of clinical biochemistry : IJCB》1996,11(2):120-123
Approaches to the stabilization of tumor markers vary depending on the lability of the tumor marker. Thus while merely freezing the serum promptly at ?70°C may be adequate for some analytes such as gastrin, some other polypeptide hormones such as vasoactive intestinal peptide require collection of blood in EDTA and prompt freezing of plasma to protect the analyte from metal oxidation. In addition to collection of blood in EDTA an addition of a proteolytic enzyme inhibitor such as aprotinin may be necessary to preserve labile polypeptide hormones such as ACTH, somatostatin etc. Analytes such as parathyroid hormone related protein (PTH-rp) are so labile that additives such as leupeptin and pepstatin have to be added to EDTA and aprotinin and the plasma refrigerated to achieve stability for up to 24 hrs. Catecholamines also require stabilization with additives such as EGTA and glutathione and prompt freezing of plasma at ?70°C. Special precautions are required in handling tumor tissue intended for hormone receptor measurements since they are not only extremely heat labile but are also subjected to alteration during specimen preparation. 相似文献
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Cryotherapy is a prospective green method for malignant tumor treatment. At low temperature, the cell viability relates with the cooling rate, temperature threshold, freezing interface, as well as ice formation. In clinical applications, the growth of ice ball must reach a suitable size as cells could not be all killed at the ice periphery. The cell death ratio at the ice periphery is important for the control of the freezing destruction. The mechanisms of cryoinjury around the ice periphery need thorough understanding. In this paper, a primary freeze-thaw control was carried out in a cell culture microchip. A series of directional freezing processes and cell responses was tested and discussed. The temperature in the microchip was manipulated by a thermoelectric cooler. The necrotic and apoptotic cells under different cryotreatment (duration of the freezing process, freeze-thaw cycle, postculture, etc.) were stained and distinguished by propidium iodide and fluorescein isothiocyanate (FITC)-Annexin V. The location of the ice front was recorded and a cell death boundary which was different from the ice front was observed. By controlling the cooling process in a microfluidic channel, it is possible to recreate a sketch of biological effect during the process of simulated cryosurgery. 相似文献
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Najma Zaheer Baquer Dhananjay Gupta Jayadev Raju 《Indian journal of clinical biochemistry : IJCB》1998,13(2):63-80
Diabetes has been classified as a disease of glucose overproduction by tissues, mainly liver and glucose underutilization
by insulin requiring tissues like liver, adipose and muscle due to lack of insulin. There is, however, glucose over utilization
in tissues not dependent on insulin for glucose transport like kidney, nerve and brain. There are serious complications due
to this excess glucose in these tissues and their reversal is important for a good metabolic control and normalisation of
other parameters. Insulin, trace metals and some plant extracts have been used to see the reversal effects of the complications
of diabetes in liver and kidney in experimental diabetes. Almost complete reversal of the metabolic changes has been achieved
in the activities of key enzymes of metabolic pathways in liver and kidney and an effective glucose control has been achieved
suggesting a combination of therapies in the treatment of metabolic disturbance of the diabetic state. 相似文献
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贵州高原西北部冻雨的时空变化特征 总被引:3,自引:1,他引:2
采用Mann-Kendall、Morlet小波分析、合成分析等方法,分析了近48a贵州西北部冻雨日数的时空分布及环流特征。结果表明:贵州西北部冻雨的空间分布差异显著,冻雨日数自东向西逐渐增多,冻雨日数出现频率最多的在威宁,年平均冻雨日数48.1d,冻雨日数出现频率最少的在六枝,年平均日数仅4.8d,贵州西北部冻雨主要出现在12月到翌年2月。近48a来贵州西北部冻雨日数呈下降趋势,年冻雨日数存在3~5a左右的周期,突变分析表明,贵州西北部冻雨日数突变特征明显,突变发生在1989年。冻雨日数偏多和偏少时期,其环流特征存在着显著的差异。 相似文献
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植物蜡质合成与分泌的研究进展 总被引:3,自引:0,他引:3
植物蜡质是指植物裸露在空气中的植物组织表皮脂质,它在降低植物非气孔水分散失,保护植物抵御紫外线、病虫害中起到重要作用.本文对近年来蜡质成份的研究及相关基因克隆的研究进展进行了综述,同时并对蜡质基因的应用前景进行了展望. 相似文献
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Quantitative feedback theory (QFT) is a powerful design technique for robust feedback control systems with plant uncertainties. In applying QFT to design robust feedback control systems, the generation of plant templates is an essential step. For a system with affinely dependent parameters and the parameter domain is a box, it is well known that the boundary of a plant template is included in the image of the set of edges of the parameter domain box. One can obtain the plant template from the image of the set of edges. However, this approach to the generation of the plant template leads to heavy computational burden since it wastes much computational effort computing the images of points on edges which lie in the interior of the plant template. In this paper, an efficient algorithm is proposed to identify, from an edge of the parameter domain box, the set of parameter points whose image lies in the interior of the plant template. The computational burden for generating the plant template thus can be obviously reduced by eliminating the identified sets of parameter points in the plant template generation procedure. Numerical examples are included to illustrate the efficiency of the algorithm. 相似文献
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周发为 《科技成果管理与研究》2011,(4):80-82
城市燃气是建设现代化城市必须具备的一整套现代化设施的组成部分,因此城市燃气管网的平稳运行和安全供气显得尤为重要。为防止由于管线冻堵影响到用户的正常用气,对于燃气管道在冬季发生冻堵的情况进行分析总结,根据冻堵的机理提出预防和解决的措施。 相似文献
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冬季咸水结冰灌溉对滨海盐碱地的改良效果研究 总被引:14,自引:0,他引:14
冬季利用地下苦咸水(9.59g/L)对滨海盐碱地进行咸水结冰灌溉,灌溉水量为180mm,咸水融化入渗完成后覆以地膜以防止返盐(T),以不灌溉同期覆膜的地块作为对照1(CK1),以不做任何处理的地块作为对照2(CK2)。种植作物为棉花。结果表明,冬季咸水灌溉结冰、春季咸水冰融化入渗后土壤各层次脱盐效果明显。春季咸水冰融水入渗后,T处理0~20cm土壤表层含盐量由灌水前的0.69%降低到0.39%,脱盐效率为43.5%,显著高于CK1和CK2;而CK1和CK2由于受冬季土壤冻融积盐和春季强烈蒸发影响,0~20cm土壤表层出现强烈的积盐,土壤平均含盐量分别从0.63%和0.58%增加到1.44%和1.27%;在棉花播种期,T处理的土壤表层含盐量为0.31%,而CK1和CK2土壤表层含盐量分别为0.65%和0.98%。由于T处理的土壤含盐量低,适于棉花的播种出苗,播种后出苗率达76.8%,最终籽棉产量达3700.17kg/hm2;而CK1和CK2由于土壤含盐量高,几乎没有棉花出苗,最终棉花绝收。 相似文献
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自然沼泽湿地生物量与CH4、N2O排放量关系初步研究 总被引:2,自引:0,他引:2
气候变化是人类所面临的全球环境问题之一,而温室气体的排放是引起气候变化的一个重要原因,因此温室气体的排放量估算是环境变化研究热点,其中对其估算方法是研究内容之一。2003年,在三江平原典型沼泽湿地,采用收割法和静态箱-气相色谱法研究不同植被类型小叶章、毛果和漂筏地上生物量及CH4、N2O排放量。通过对地上植物生物量与CH4、N2O排放量数据分析表明,在地上生物量达到最大前,三江平原沼泽湿地生长季不同植被群落生物量与CH4、N2O排放累积量呈现强的线性相关。可用Y=b1X+b0函数表示,R2都在0.89以上。 相似文献
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支持向量机在植物分类中的应用 总被引:1,自引:0,他引:1
提出了基于支持向量机的分类原理对鸢尾属植物进行分类的方法。支持向量机是在统计学习理论基础上提出的一种新型的通用学习方法,主要应用于数据的分类和回归估计,而植物分类的主要依据是植物的外观特征。通过提取植物的特征数据和使用支持向量机算法获得实验结果,实验结果表明,采用支持向量机对植物分类是可行的。 相似文献
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针对深厚表土层冻结法凿井井壁安全,从冻结压力、提高井壁强度,尤其是高强度高性能混凝土配制等几个方面进行分析研究,对于以后类似地层条件下冻结法凿井井壁设计和施工安全有一定的借鉴和参考作用。 相似文献