980 resultados para 616.992


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本文对珠芽蓼果实的营养成分进行了分析.结果表明,珠芽蓼果实含有丰富的蛋白质、总糖、氨基酸和矿质元素,是一种值得有效开发的野生植物资源.

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研究细穗香薷(Elsholtzia ianthina)的挥发油成分.采用水蒸气蒸馏法提取,用气相色谱质谱联用技术进行分析,用面积归一法计算出有关的相对含量,鉴定出45个化合物,主要的挥发油化学成分为三环[4.3.1.13,8]十一烷-1-醇,2,3,5,6-四甲基酚,共占挥发油总量的56.29%.

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系统报道了中藏药款冬大小孢子的发生、雌雄配子体发育和胚胎的发育过程。药壁发育双子叶型; 绒毡层发育接近菊科中的“The Com os bip innatus”型; 成熟花粉为3 细胞型; 单珠被, 薄珠心, 倒生胚珠;具发达的珠被绒毡层;胚囊发育4 孢子型, 接近五福花(A d ox a)型胚囊。受精作用属于有丝分裂前配子体融合类型。胚乳发育为核型。胚胎发育为紫菀型千里光变型。讨论了该种胚胎学特征的生态学及系统学意义。

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分析了高寒草甸地区冷季降水和土壤水分资源分布特征及其对牧草产量的可能影响。结果表明: 祁连山海北高寒草甸地区冷季降水资源贫乏, 但9~ 10 月较高的降水受枯黄植被蒸散量小、植被盖度大的影响, 易贮存于土壤。加之地处高寒, 气温低, 土壤封冻早, 冻结期长,使土壤水分在冬季可以冰晶水的形式留存于土体, 从而给来年牧草进入正常营养生长发育阶段提供了水分条件的需求。牧草产量的高低与冷季降水及土壤水分条件有一定的联系性。建立冷季降水与牧草产量间的预报方程, 其拟合率高。

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分析了自治水下机器人 (AUV )的控制特点 ,论述了滑模模糊控制 (SMFC)的基本原理 ,并在6 0 0 0 m自治水下机器人“CR- 0 2”上进行了仿真和水池实验。结果表明 ,滑模模糊控制的性能明显优于PID控制 ,在强干扰时表现出良好的鲁棒性

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利用动力学通量箱法与高时间分辨率大气测汞仪的联用技术, 在瑞典西南的Kristineberg海洋观测站(KMRS)和Knobesholm的Hovgårdsån河分别测定了夏季海水和河水表面与大气间汞的交换通量. 在夏季, 河水和海水都是大气汞的源. 河水和海水表面与大气间汞的交换通量在夏季具有一致的昼夜变化规律, 白天由水体向大气排汞且在正午达到最大值; 夜间排汞量相对较小且有时会出现大气汞向水体沉降. 河水与大气间汞的交换通量与光照强度呈线性正相关关系, 与大气相对湿度呈线性负相关性, 同时还与水体温度存在指数相关性. 海水与大气间汞交换通量只与光照强度存在良好的线性正相关关系. 水体中溶解态气汞的过饱和是水体汞向大气释放的驱动力.

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使用0. 5 mol/L NaOH和0. 1 mol/L Na4 P2O7 溶液分别从土壤中提取胡敏酸,并且对其进行了元素分析、红外光谱、固态13C核磁共振的定性、定量研究。结果表明,两种胡敏酸的性质很相似,但也存在一些微小差异,Na4 P2O7 提取的胡敏酸比NaOH提取的具有芳香度较大、聚合度较高、极性官能团含量较多的特点。测定了菲在6个胡敏酸上的吸附等温线, Freundlich模型很好的拟合了所有吸附等温线,相关系数r均在0. 992以上。有机碳分配系数Koc与胡敏酸中极性碳(POC)之间存在明显的线性相关关系,并受到提取剂类型的影响。

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四川盐边高家村镁铁-超镁铁质杂岩体是一个分异良好的似层状侵入体, 该岩体可以分为两个堆积旋回. 对高家村杂岩体主体岩相的角闪辉长岩进行系统的单颗粒锆石U-Pb定年以及单矿物角闪石40Ar/39Ar定年的研究, 表明高家村杂岩体的主体岩相形成年龄为840±5 Ma. 对“盐边蛇绿岩”的提法提出了质疑, 认为高家村杂岩体的形成很可能与Rodinia超级大陆下的一个超级地幔柱活动有关. 以上的研究成果有助于重新认识盐边地区新元古代构造演化特征.

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秦岭造山带是华北与扬子两大古板块的接合带,在空间上,自北而南,秦岭造山带可分为华北板块南缘(华熊地块)、北秦岭造山带、南秦岭造山带和扬子板块北缘等4个构造单元。小秦岭金矿田位于华熊地块北缘,是国内外学者共识的造山型金矿田,河南灵宝大湖金-钼矿床位于小秦岭金矿田,属断控脉状矿床。大湖金-钼矿床最先正是以金矿床进行勘查的,其黄金储量28t,平均品位8.7g/t。随着开采深度的加大,部分含金石英脉向深部转变为辉钼矿-石英脉,目前探明钼资源量已达中型规模。 本论文主要从区域地质背景、矿床地质特征、元素地球化学、同位素地球化学、流体包裹体地球化学、矿床年代学及成矿机理等角度对大湖金-钼矿床进行了较为系统的研究,主要获得如下认识: 成矿过程经历3个阶段:早阶段为黄铁矿-石英脉,遭受变形、破碎,应形成于挤压或压剪过程;中阶段为细粒的辉钼矿-黄铁矿-石英网脉,贯入到早阶段黄铁矿或石英矿物的裂隙(可呈共轭状),应形成于剪切环境;晚阶段石英-碳酸盐细脉具梳状构造,充填于张性或张扭性裂隙。 大湖金-钼矿床的金属硫化物ISr=0.70470-0.71312,平均0.70854;(143Nd/144Nd)i=0.51143-0.51215,平均0.51162;(206Pb/204Pb)i=17.033-17.285,(207Pb/204Pb)i=15.358-15.438,(208Pb/204Pb)i = 37.307-37.582。其围岩太华群样品平均值ISr=0.72294,(143Nd/144Nd)i=0.51107,(206Pb/204Pb)i=17.127-18.392,(207Pb/204Pb)i =15.416-15.604,(208Pb/204Pb)i=37.498-37.814,它们的平均值分别是17.547,15.470,37.616。通过金属硫化物及围岩太华群的对比,可以看出,成矿物质具有太华群和深部地幔混合的特征。 通过对不同阶段的含矿石英脉中的流体包裹体特征研究表明,早阶段只发育CO2-H2O型流体包裹体;中阶段流体包裹体类型复杂,有纯CO2型、CO2-H2O型、H2O-NaCl型和含子晶包裹体,指示流体沸腾作用强烈;而晚阶段只发育水溶液包裹体。早、中、晚3个阶段的流体包裹体均一温度分别集中在400-500℃、290-470℃、220-260℃;估计的早、中阶段流体的最低捕获压力分别为138-331MPa和78-237MPa,对应于成矿深度分别为13.8-11.0km和7.8-8.0km。早、中阶段的压力反应出静岩压力到静水压力的转变。成矿温度和压力明显高于浅部含金石英脉的成矿温度120-310℃,成矿压力100-150MPa。与野外观察到的“上金下钼”的空间关系一致。 大湖金-钼矿床辉钼矿-石英脉Re-Os同位素模式年龄较集中,介于215.4±5.4-255.6±9.6Ma,Re-0s等时线年龄为218±41Ma(MSWD=38,2σ误差),表明大湖金-钼矿的辉矿化形成于印支期。 三叠纪末,随着古秦岭洋的逐渐封闭,处在弧后转换带的深部岩石在挤压作用下发生变质脱水而形成初始成矿流体,成矿流体沿断裂带(韧性剪切带)向上迁移而引起大湖钼矿床成矿系统的发育。随着区域构造环境由挤压转为伸展,区域的变质脱水更强,形成大量成矿流体,变质流体上侵为浅层流体循环提供了的热能,而浅层构造也因减压扩容而为流体循环提供了通道,这无疑有利于浅层流体循环和混入成矿系统。同时,增温和减压也有利于成矿流体发生沸腾。因此,充足的流体、热以及强烈的流体沸腾等,势必导致发生最为强烈的成矿物质快速沉淀作用。随着挤压作用的减弱,伸展作用的增强,区域热异常消失,地壳深部组分发生亏损,流体以浅源大气降水占主导,成矿作用迅速衰竭,形成石英-碳酸盐网脉,对成矿作用贡献减弱。总之,通过对大湖金钼矿床研究表明,大湖金钼矿床形成于由挤压转向伸展的构造背景,这与矿床地质的特征一致。

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A novel mode of capillary electrochromatography (CEC), called dynamically modified strong cation-exchange CEC (DMSCX-CEC), is described in this paper. A column packed with a strong cation-exchange (SCX) packing material was dynamically modified with a long-chain quaternary ammonium salt, cetyltrimethylammonium bromide (CTAB), which was added to the mobile phase. CTAB ions were adsorbed onto the surface of the SCX packing material, and the resulting hydrophobic layer on this packing was used as the stationary phase. Using the dynamically modified SCX column, neutral solutes were separated with the CEC mode. The highest number of theoretical plates obtained was about 190 000/m, and the relative standard deviations (RSD's) for migration times and capacity factors of alkylbenzenes were less than 1.0% and 2.0% for five consecutive runs, respectively. The effects of CTAB and methanol concentrations and the pH value of the mobile phase on the electroosmotic flow and the separation mechanism were investigated. Excellent simultaneous separation of the basic and neutral solutes in DMSCX-CEC with a high-pH mobile phase was obtained, A mixture containing the acidic, basic, and neutral compounds was well separated in this mode with a low-pH mobile phase; however, peak tailing for basic compounds was observed in this mobile phase.

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A cultura de arroz no Estado do Acre é conduzida sob regime de "sequeiro favorecido", no que se refere à pluviosidade. Há uma grande procura no mercado consumidor pelo arroz da classe longo fino ("agulhinha"), de boa aparência, antes e depois do cozimento e de alto rendimento na panela. As cultivares tradicionalmente plantadas no Acre produzem grãos da classe longo, cuja procura está em declínio, incluindo-se a variedade Xingu, apesar de bem adaptada e como bom desempenho em solos da baixa fertilidade. Com o desenvolvimento de variedades melhoradas, adaptadas às condições de clima, solo em manejo da região, é possível aumentar a produtividade de cultura e, ao mesmo tempo, atender às exigências do mercado local quanto à qualidade. O aumento da produtividade pelo melhoramento genético e pelo aperfeiçoamento do sistema de cultivo, pode resultar em uma redução da pressão de desmatamento.