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介绍了Web前台开发技术jQuery在Eclipse3.5下的编程环境设置和编辑与运行jQuery程序的方法。 相似文献
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本文介绍了不同利用年限的红壤水稻土中重金属元素As、Cd、Cr、Cu、Ni、Pb和Zn的含量变化,利用年限分别为3、10、15、30和80年。研究结果表明,虽然红壤水稻土中不同的重金属元素含量的变化趋势有所差异,但总体上重金属元素含量随利用年限的延长而降低,并可能达到一个相对稳定的水平;施用未经处理的城市垃圾会导致水稻土中某些重金属元素含量明显升高;研究区的水稻土已发生Cd和Cu污染。 相似文献
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通过对土壤调理剂主要原料的分类分析,研究我国主要土壤调理剂产品中Hg、As、Cd、Pb、Cr 5种重金属元素含量及不合格率等现状,就相关原料农业资源化利用进行探讨,为我国土壤调理剂行业管理提供技术支撑。分析样品主要来自农业部肥料登记检验样品,部分样品来自企业质量跟踪或质量复核样品,以及调研采集样品;采用农业推荐性标准NY/T 1978-2010《肥料汞、砷、镉、铅、铬含量的测定》进行重金属元素含量检测,根据农业部肥料和土壤调理剂登记标准进行结果判定。在4种类型的土壤调理剂中,有机源土壤调理剂、化学源土壤调理剂和农林保水剂3类产品在本试验所有样本中均未出现不合格情况。矿物源土壤调理剂中存在As、Pb、Cr3种重金属元素超过限量规定的情况,尤其Pb元素导致的不合格率达20.9%,Pb含量检测平均值为42.5 mg/kg,已经接近限量标准(50 mg/kg),Pb含量最高检测值达到204 mg/kg,是导致矿物源土壤调理剂不合格的主要原因。通过土壤调理剂主要原料的分类分析,发现导致Pb元素超标所用原料主要包括钾长石、牡蛎壳、钢渣、钼尾矿、磷矿石+碱渣等5种。因此,我国土壤调理剂产品中重金属元素情况总体处于相对安全的水平范围内,有机源土壤调理剂、化学源土壤调理剂和农林保水剂质量情况较好,而矿物源土壤调理剂中As、Pb、Cr元素存在一定质量问题,尤其是Pb元素质量问题突出。关于钾长石、牡蛎壳作为土壤调理剂原料农用,笔者认为应注意严格控制重金属元素含量,避免因原料引起产品重金属元素超标,而钢渣则建议慎重作为土壤调理剂原料使用。 相似文献
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在限制小麦灌溉面积的大背景下,为进一步稳产促优,本文探讨了华北地区水分亏缺对不同小麦品种矿质元素吸收、分布特性及其与植株水分利用和产量的关系。选用3个生态类型冬小麦品种(抗旱品种‘沧麦6001’、丰水高产品种‘邯麦9’和多抗超高产品种‘济麦22’),设置正常和水分亏缺两个水平的人工气候室箱体栽培试验,主要调查了小麦不同器官矿质元素含量、积累量变化、分配比以及矿质元素变化对水分利用效率和产量的影响。结果表明,矿质元素的含量和分配具有器官特异性,其中小麦叶片Ca、籽粒Cu和Zn、茎秆Na的含量、分配比最高;Fe含量、积累量及Fe分配比因品种、器官、水分差异而不同:正常水分下,‘沧麦6001’以茎秆、‘邯麦9’以叶片的Fe含量、分配比最高;‘济麦22’以茎秆和颖壳Fe含量较高,以叶片和颖壳Fe分配比较高。而水分亏缺下,‘沧麦6001’和‘邯麦9’Fe含量以籽粒最高,‘济麦22’以叶片最高;3品种Fe分配比均以籽粒最高。此外,水分亏缺增加了小麦籽粒Cu、Zn含量及分配比,籽粒Zn、Na和Ca积累量,显著增加‘沧麦6001’的水分利用效率和产量以及‘济麦22’的产量水分利用效率;而降低了‘沧麦6001’籽粒Mn、‘邯麦9’籽粒Cu和Mn、‘济麦22’籽粒Cu和Fe积累量以及‘邯麦9’水分利用效率、干物重、产量。综上,水分亏缺下,‘沧麦6001’更易高产高效,籽粒Fe含量增加,但需补充一定的Mn元素;‘济麦22’的水分利用效率增加,产量未显著下降,需补充一定Fe元素保证品质;‘邯麦9’产量和水分利用效率均显著下降,且籽粒中Cu和Mn积累下降明显。相关分析表明,Cu、Zn、Ca、Mn含量与干物重变化之间存在一定的相互调节作用,但未直接影响产量和水分利用效率,这可能与品种间差异及品种和水分互作影响有关。但矿质元素可能通过影响干物重间接调控水分利用效率的趋势是存在的,尚需进一步研究和验证。 相似文献
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Field portable X-ray fluorescence (PXRF) spectrometry has become an increasingly popular technique for in-situ elemental characterization of soils. The technique is fast, portable, and accurate, requiring minimal sample preparation and no consumables. However, soil moisture 〉 20% has been known to cause fluorescence denudation and error in elemental reporting and few studies have evaluated the presence of soil moisture in solid form as ice. Gelisols (USDA Soil Taxonomy), permafrost-affected soils, cover a large amount of the land surface in the northern and southern hemispheres. Thus, the applicability of PXRF in those areas requires further investigation. PXRF was used to scan the elemental composition (Ba, Ca, Cr, Fe, K, Mn, Pb, Rb, Sr, Ti, Zn, and Zr) of 13 pedons in central and northern Alaska, USA. Four types of scans were completed: 1) in-situ frozen soil, 2) re-frozen soil in the laboratory, 3) melted soil/water mixture in the laboratory, and 4) moisture-corrected soil. All were then compared to oven dry soil scans. Results showed that the majority of PXRF readings from in-situ, re-frozen, and melted samples were significantly underestimated, compared to the readings on oven dry samples, owing to the interference expected by moisture. However, when the moisture contents were divided into 〉 40% and 〈 40〈 groups, the PXRF readings under different scanning conditions performed better in the group with 〈 40% moisture contents. Most elements of the scans on the melted samples with 〈 40% moisture contents acceptably compared to those of the dry samples, with R2 values ranging from 0.446 (Mn) to 0.930 (St). However, underestimation of the melted samples was still quite apparent. Moisture-corrected sample PXRF readings provided the best correlation to those of the dry, ground samples as indicated by higher R2 values, lower root mean square errors (RMSEs), and slopes closer to 1 in linear regression equations. However, the in-situ (frozen) sample scans did not differ appreciably from the melted sample scans in their correlations to dry sample scans in terms of R2 values (0.81 vs. 0.88), RMSEs (1.06 vs. 0.85), and slopes (0.88 vs. 0.92). Notably, all of those relationships improved for the group with moisture contents 〈 40%. 相似文献
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利用地统计学的方法,对贵州水城岩溶盆地复合土地利用方式下土壤微量重金属元素含量的时空变异进行了研究。结果表明:贵州水城盆地岩溶土壤微量重金属元素含量的变化与不同的土地利用方式时空上的变异有很好的一致性。盆地中工业区往往成为土壤微量重金属元素迁移富集的高值中心,而受人类活动影响较小的自然林区则基本保持了原始状况成为低值中心。因此合理进行土地利用对保护土壤和岩溶地下水免受污染具有重要的意义。 相似文献
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选取亚热带花岗岩区不同利用方式下的3个相邻小流域(F:100%森林;FA1:82%森林+18%农田;FA2:76%森林+24%农田),通过定期监测与分析雨水和径流水的元素组成,获得了流域尺度元素的降水输入与径流输出特征,在此基础上分析了元素收支平衡及其对土壤酸化的影响。结果表明:雨水中离子输入总量为181.74 kg/(hm~2·a),夏季输入量约占全年输入量的45%,Ca~(2+)、Na~+和NH_4~+约占阳离子输入总量的80%,SO_4~(2–)和NO_3~–约占阴离子输入总量的74%。F、FA1和FA2流域径流水中离子输出总量分别为236.81,153.17和243.36 kg/(hm~2·a),夏季输出量约占全年输出量的39%~47%,Ca~(2+)和Na~+约占阳离子输出总量的81%~86%,SO_4~(2–)和NO_3~–约占阴离子输出总量的65%~70%。降水和径流水的元素收支平衡表明,F、FA1和FA2流域中SO_4~(2–)、NO_3~–、Cl~–、NH_4~+和H~+均表现为净输入,其中SO_4~(2–)的净滞留量最高,分别为13.7、30.43和20.49 kg/(hm~2·a);而Ca~(2+)、Mg~(2+)和Na~+均表现为净输出,其中Na~+的净输出量最高,分别为28.99、14.96和31.76 kg/(hm~2·a)。F、FA1和FA2流域内酸雨直接输入的H~+为818 mol/(hm~2·a),而流域内氮素转化产生的H~+分别为396、389和401 mol/(hm~2·a),占H~+输入总量的32%~33%。F、FA1和FA2流域的土壤酸化速率分别为996、1 069和1 035 mol/(hm~2·a),表明即使不考虑农业施肥的情况下农林复合流域(FA1和FA2)的土壤酸化速率仍高于森林流域(F)。 相似文献
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对煤矸石及其周围土壤、水体、大气,以及煤矸石山上植物体中重金属元素的有关研究分析表明1)我国大多数矿区煤矸石属于普通固体废弃物,重金属元素超标倍数不大;2)煤矸石山对周围土壤、水体、大气影响较小,但其本身不宜生产具有食用价值的植物产品;3)煤矸石植被恢复后,大多数植物体内重金属元素含量超过蔬菜限量物质指标. 相似文献
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采用3种方法:M3-双硫腙、DTPA-AAS、EDTA-AAS测定了土壤中有效态锌的含量,并且进行比较,研究了M3-双硫腙方法的精密度、重现性,并分别进行了M3浸提剂及双硫腙萃取剂重现性的重现性实验。结果表明:M3-双硫腙法与标准参比法呈显著相关,M3浸提剂及双硫腙萃取剂的重现性好。M3-双硫腙法精密度高、工效快,可用于土壤重金属的联合速测。 相似文献
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该研究探讨了矿物元素指纹分析技术对黑龙江黄豆产地溯源的可行性,筛选出判别黑龙江黄豆产地溯源的有效指标。利用电感耦合等离子体质谱仪(inductively coupled plasma mass spectrometry,ICP-MS)测定来自齐齐哈尔和北安2个地域50份黄豆样品中52种矿物元素的含量,并对数据进行了方差分析、主成分分析和判别分析。研究表明,46种矿物元素含量在地域间存在显著差异,通过逐步判别分析筛选出8项元素指标建立黄豆产地判别模型,所建立的模型对黄豆产地整体交叉检验判别率为95.7%。As、Ru、Gd含量在黄豆与土壤间呈显著正相关(P0.05),Tb含量在黄豆与土壤间呈极显著正相关(P0.01),由4种元素建立的判别模型对产地判别准确。因此,上述元素是黄豆矿物元素产地鉴别较可靠的指纹信息指标。 相似文献
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PurposeThe use of rare earth elements (REEs) as tracers provides a high-precision method for quantitative determinations of soil particle movement in soil erosion studies. In this study, a new calculation method was developed and tested to improve the precision of the REE tracing method and to expand the application of this method to areas with coarse-textured soils. Materials and methodsThis study used purple soil to simulate a catchment with data based on a field survey of a small catchment located in the Three Gorges Area in China. Eight different powdered rare earth oxides, which included La2O3, CeO2, Nd2O3, Sm2O3, Eu2O3, Tb4O7, Ho2O3 and Yb2O3, were applied as tracers to describe soil movement in this scaled catchment during three simulated rainfall events of 1.0, 1.5 and 2.0 mm min?1 rainfall intensity. Leaching experiments were conducted to investigate the vertical migration of REEs in soil layers. Particle size distributions (PSDs) and REE concentrations for each soil particle size class (1–2, 0.5–1, 0.25–0.5, 0.1–0.25, 0.075–0.1, 0.05–0.075, 0.02–0.05, 0.005–0.02 and <0.005 mm) were analysed to evaluate the precision of the proposed calculation method. Results and discussionMost REEs remained in the first layer during leaching. The scanning electron microscopy-energy dispersive X-ray (SEM-EDX) mapping images showed that more REEs were adsorbed by small particles (≤0.1 mm), with large specific surface areas, than by large particles (>0.1 mm). During the three rainfall events, the coarsest size classes (1–2 and 0.5–1 mm) of the sediment samples were less than that of the soil. In contrast, the other classes, including <0.075 mm, showed the strongest adsorption for REEs, and the weight percentage of grains in eroded sediment was more than that in the source soil. The accuracy of the new proposed calculation method increased by 24.37, 20.25 and 3.84 % for the first, second and third storm, respectively, compared with the uncorrected mass of soil loss from the scaled catchment. ConclusionsThe REEs bonded well with purple soil particles and the leaching of REEs from the tagged layer to the lower layers was minimal. The <0.075-mm particle size class had the strongest adsorption capacity for REEs. The soil loss estimates were improved with the new calculation method. 相似文献
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为了明确变化环境下流域未来气候要素时空变化趋势及特征,该文以泾河流域为研究对象,利用流域1960-2010的逐月降水、气温和NCEP再分析等资料,建立了流域气候要素月序列降尺度模型;然后,将模型应用于CMIP5中CNRM-CM5模式下的RCP4.5和RCP8.5情景,得到了流域未来气候要素的变化趋势。主要成果如下:1)该方法对气温的模拟效果较好,降水次之;2)RCP8.5情景下泾河流域未来年均降水量是356.41 mm,小于RCP4.5情景下的374.19 mm;除冬季外,流域未来春、夏及初秋的降水将有所减少,空间分布在南北方向呈现递减趋势;3)RCP8.5情景下泾河流域未来年均温度是9.32℃,高于RCP4.5情景下的8.96℃;流域未来气温除了深冬初春降低外,其余时期尤其是夏季将显著上升,空间分布为南高北低、西高东低。对泾河流域气候要素模拟与预估表明,泾河流域未来气候演变中存在着降水减少以及极端天气事件发生的风险,这在流域未来水资源管理运行等方面应当引起重视。 相似文献
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pp. 881–889 In order to understand the influences of nitrogen and silicate fertilizer application on anther length and percentage of the sterility of the rice plant, we investigated by field experiment in Hokkaido Kamikawa Agric. Exp. Stn. (Brown Lowland soil) and by air-conditioned room experiment. The results are summarized as follows. 1) Application of silicate fertilizer decreased percentage of sterility. Compared with basal application, topdressing of silicate fertilizer was more effective in increasing carbohydrate content and anther length, decreasing percentage of sterility. 2) The anther length was negatively correlated to percentage of sterility and was positively correlated to carbohydrate content in the rice plant. Similar regression curves were plotted between the field experiment and the air-conditioned room experiment. 3) Silicate content in rice plants was increased at the flag leaf stage by applying both basal and topdressing silicate fertilizer. Furthermore, silicate content was correlated to carbohydrate content. Nitrogen content was negatively correlated to carbohydrate content. 4) Protein content in polished rice was decreased by silicate fertilizer application. 相似文献
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pp. 875–880 The trace-element composition of kernel in pickled Japanese apricot ( Prunus mume Sieb. et Zucc.) was determined using an inductively coupled plasma optical emission spectrometer in order to distinguish between Japanese products and Chinese products. Strontium and barium concentrations in the kernels of Chinese products were 10 or more times those of the Japanese ones. When based on 8.0 mg kg ?1 of strontium concentration in kernel, 93.2% of sample was distinguished as Japanese products or Chinese ones. Applying principal component analysis using 9 elements (Mn, Zn, Fe, Ni, Ba, Sr, Cu, Co, Cr), the pickled Japanese apricots tend to separate into two countries. Linear discriminant analysis (LDA) using 9 elements allowed a reasonable classification of pickled Japanese apricots according to the country of production. The result of the analysis of K-nearest neighbors (KNN) was better than that of LDA. 相似文献
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自私遗传元件(SGEs)采用对自身有利的方式进行传递,它们在生物中广泛存在,在生物进化中具有不可替代的重要作用。SGEs被认为是生物基因组的重要部分,它们以低拷贝数长期稳定地寄生在宿主及其基因组中。SGEs的种类很多,所熟知的有转座元件、Wolbachia、B染色体、减数分裂驱动元件、限制-修饰系统和Medea基因等。为了加强自身的传播,这些元件通过许多方法操控宿主配子发生过程或宿主生殖,如诱导减数分裂驱动或胞质不亲和性和雌性化、雄性致死或雄性不育等。它们对宿主的调控和宿主基因组对这种调控的反应可能暗含着性别决定的进化、物种形成等重要机制。本文对SGEs的种类及其作用的研究进展进行了综述。 相似文献
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In order to evaluate the possibility of contamination of soil with trace elements by the application of sludges to soil, the contents of rare earth elements (REEs; La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) and other trace elements (Be, As, Ag, Cd, Sb, Cs, Bi, and U) in wastewater treatment sludges were determined. In sludges of night soil treatment plants (night soil sludges) and sludges of wastewater treatment plants in the food industry (food industry sludges), the distribution patterns of REEs normalized versus average REEs in the continental crust were almost flat. It was considered that the REE patterns of uncontaminated sludges reflected the pattern of the continental crust. The crust-normalized REE patterns of sludges of wastewater treatment plants in the chemical industry (chemical industry sludges) and municipal sewage sludges did not always show flat plots. The sludges that did not show a flat REE pattern were considered to be contaminated with some of the REEs. The coefficient of variation of each element determined among the 10 samples of night soil sludges and the 14 samples of sewage sludges ranged from 34 to 77% and from 26 to 84%, respectively. Among the 10 samples of food industry sludges and the 10 samples of chemical industry sludges, the coefficient ranged from 60 to 143% and from 67 to 172%, respectively. The variations of the content of each element among the food industry sludges or the chemical industry sludges were larger than those among the night soil sludges or the sewage sludges. The contents of Be, As, Cs, REEs, and U in all the sludges were lower than or the same as those in a field soil. Some of the food and chemical industry sludges contained larger amounts of Ag, Cd, and Sb than the soil. All the night soil sludges and sewage sludges contained much larger amounts of Ag and Bi than the soil. 相似文献
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Abstract To assess soil-to-plant transfer of various elements more precisely, the concentrations of the elements extracted from soil samples using eight chemical solutions were compared with the results of a pot cultivation experiment of komatsuna ( Brassica rapa L. var. perviridis) or buckwheat ( Fagopyrum esculentum M.) using the soils. From agricultural fields in Aomori, Japan, 16 soil samples were collected. Elements in the samples were extracted using acids (1 mol L ?1 HNO 3, 0.1 mol L ?1 HNO 3, 0.01 mol L ?1 HNO 3), chelating agents (0.05 mol L ?1 EDTA), neutral salt solutions (1 mol L ?1 NH 4OAc, 1 mol L ?1 NH 4NO 3, 0.01 mol L ?1 CaCl 2) and pure water. The 28 elements in the extracted solutions and plant samples were determined. The extractability of many metals was higher in 1 mol L ?1 HNO 3, 0.1 mol L ?1 HNO 3 and the 0.05 mol L ?1 EDTA solutions than in the other extractants. Higher extractability using the NH 4OAc solution than the NH 4NO 3 solution was observed for some elements, in particular U. Extractability by pure water was not always lowest among these methods, probably because of dispersion of colloidal substances in the extracted solution. The pot cultivation experiment showed that the concentrations in soil and in the extracted fraction using 1 mol L ?1 HNO 3, 0.1 mol L ?1 HNO 3 or the EDTA solution did not correlate with the concentration in plant samples for most elements. Plant uptake of Zn, Y and La by komatsuna correlated well with their concentrations in extracts with neutral salt solutions or 0.01 mol L ?1 HNO 3. Concentrations of Al, Cu and Cd in buckwheat were also correlated with the concentrations in the extracts. 相似文献
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