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我国拥有居世界第二的草地资源,然而由于自然和人为因素使得我国的天然草场正在遭受不同程度的退化。导致草原生态岌岌可危。本文在深入分析导致草原退化的制度原因的基础上,论证了草原私有化和产权明晰等制度设置由于执行成本过高、监督不当等原因并不能草原使退化得到缓解。而且制度本身的缺陷加上执行过程中的偏差反而会加重草原生态的恶化,在文章最后提出作者对有效缓解草原退化的相关建议。 相似文献
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氮、磷、钾是农作物需要三大主要元素,缺一不可,称为作物必需元素。硅是水稻生长过程中所需要大量元素,水稻在生育过程中所需硅量是氮、磷、钾总和的2倍,虽然它不是必需元素,却是营养需求量最大的无素。近几年来,随着氮、磷、钾肥用量逐年增加,水稻产量有了大幅度的提高。但逐年种植土壤中硅含量相对降低,因此以成为高产再高产的制约因素,表现为秆软,易生病虫害,对此,我县开展氮、磷、钾硅配比试验。 相似文献
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本文把自然场景下的图像作为系统识别的研究对象,采用特征提取与SVM分类相结合的方法,能够快速、准确、高效的分类识别出交通标志,并能有效克服形状变换、光照、颜色退化的影响。 相似文献
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硝酸分解磷矿粉生产硝基节酸磷肥 总被引:2,自引:0,他引:2
在硫资源缺乏且需要硝态氮的作物区,可以适当的发展硝基节酸磷肥。硝态氮能直接被作物吸收,属于速效性肥料,可用作追肥或寒冷季节作物施肥。不含重金属离子的废酸与磷矿粉混合后,作为硝基磷肥,既解决了废酸处理问题,又同时副产肥料。采用不足量的硝酸来分解磷矿,生产硝基节酸磷肥,综合分析,较佳的反应条件为磷矿粉与折纯硝酸质量比为1.0~1.2,烘干固化温度120℃左右,烘干固化时间8h。该方法处理后,矿粉分解率74.41%,所得硝基磷肥总养分为25.09%,其中有效磷17.55%,硝态氮7.54%。 相似文献
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洗涤剂中磷酸盐对水域的污染危害及防治对策 总被引:1,自引:0,他引:1
通过对洗涤剂中磷酸盐流入江河湖海引起赤潮污染造成巨大经济损失的分析。提出只有通过政府等部门立法洗涤剂禁磷,才是能决磷酸盐污染的最佳方法。并介绍了新型无磷助洗剂层硅是替代三聚磷酸钠的最佳产品。 相似文献
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采用火焰原子吸收分光光度法测定食品添加剂磷酸氢二铵中的铅含量,并对最低检出限、精密度、回收率、扣除背景及酸的控制等方面进行了实验,结果表明具有很好的可行性和实用性。 相似文献
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MARY E. PURCHASE CAROL K. BERNING ANNE L. LYNG 《International Journal of Consumer Studies》1982,6(4):301-317
This paper develops the national average cost of washing clothes by examining consumer research data on the frequencies of using various water temperature settings and laundry additives and by utilizing national surveys of laundry product prices. Variations in these costs are shown to be significantly affected by three variables: (1) costs increase with family size due to the higher number of loads washed, (2) costs increase in areas where phosphate detergents are not available due to an increased use of hot water and laundry additives and (3) costs increase in harder water areas due to an increased use of hot water and fabric softener. The average increased cost for energy and laundry additives per family due to the nonavailability of phosphate detergents exceeds $11.00 per year. In addition to this amount, increased wear on washing machine parts and fabrics from the use of carbonate-built detergents significantly increases the costs to consumers in nonphosphate areas. 相似文献
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模拟污泥好氧堆肥系统,将本实验室筛选所得嗜热高效降解复合菌F12,按投加量2%、5%及10%投加至堆肥体系中,研究该复合菌合适的堆肥接种量及对堆体的降解特性。结果表明,投加量为5%时堆肥效果最好,接种复合菌可提高堆体温度、延长堆肥高温期,实验组高温期可维持4 d,较对照组的1 d效果显著;与对照组相比含水率下降较多,相差5.7%;接种该复合菌有助于有机质的降解,7 d降解率与对照组的差值为3%。pH和氨气含量的变化反映了接种有利于有机质代谢,但对堆肥的保氮效果较差,堆肥产品农用质量下降,需进一步做这方面的研究;三种接种比例实验组的细菌、真菌及放线菌数量均大于对照组,外源接种给堆体带来更多微生物,加速了有机质的降解。 相似文献
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DONNA M. BROWN BRUCE A. CAMERON SONYA S. MEYER 《International Journal of Consumer Studies》1993,17(2):145-152
The effectiveness of 11 non-phosphate containing powdered detergents and 12 phosphate containing powdered detergents, of varying formulations, in cleaning a standard soiled fabric in soft water (5 ppm) were evaluated. It was found that in soft water there were no differences between washing with either phosphate or non-phosphate detergent. In general, washing with detergents which contained phosphates did give somewhat better results in warm water. Detergents that contained bleach as an additive did not result in a whiter fabric. 相似文献
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研究了固体超强酸SO42-/TiO2-SnO2-Al2O3催化衣康酸与异辛醇合成衣康酸二异辛酯的酯化反应,甲苯作为带水剂,考察了催化剂种类,确定以SO24-/TiO2-SnO2-Al2O3为催化剂。随后考察反应物配比、催化剂用量、反应时间等因素对酯化反应的影响,确定了最佳工艺条件为n(衣康酸):n(异辛醇)=1:3,催化剂用量4.5%(质量分数),反应时间2h。在该条件下,衣康酸转化率达到98.9%,产物衣康酸二异辛酯的收率为96.2%。并对SO24-/TiO2-SnO2-Al2O3的重复使用性能进行考察,结果表明,与SO24-/TiO2相比,SO42-/TiO2-SnO2-Al2O3在重复使用5次后仍具有较高的催化活性,衣康酸转化率和衣康酸二异辛酯收率为分别为98.2%和95.7%,说明载体中添加Sn和Al对于增加固体超强酸的寿命起了主要作用。 相似文献
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A multidimensional measure of ethical culture (EC) was examined for its relationship to person–organization (P–O) fit, ethical intent and organizational citizenship behavior (OCB), using a sample of 525 employees from the financial industry in Spain. As hypothesized, relative to studies using unidimensional assessments, our measure of EC was more strongly related to ethical intent and organizational citizenship. Also, significant differences were found in the degree to which each the EC dimensions related to both ethical intent and OCB. Finally, in a first for the literature, we demonstrated the important role of overall P–O fit in connection with EC, ethical intent, and organizational citizenship. Specifically, as hypothesized, P–O fit moderated positively the association between EC and ethical intent, but mediated the EC–OCB relationship. 相似文献