968 resultados para H 460.7 C572c
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目的 研究藏药市场上9种“藏茵陈”植物中有效化学成分,根据所含成分的差异及其生理活性,确定这些植物的药用价值。方法 采用HPLC法测定7种成分的量。结果 9种植物的有效成分差异很大。结论 针对不同的化学成分用途,选择不同的植物,有效利用资源。[著者文摘]
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根据天然草地退化程度的差异,采用松耙+补播+施肥+封育(退化较严重的草地)、封育+施肥(轻度退化草地)等措施,植物群落物种组成、多样性等特征值及其植被盖度发生明显变化.研究第2年结果表明,物种数封育+施肥处理最高(32种),对照居中(26种),补播+施肥处理最低(13种);多样性指数大小依次为封育+施肥(3.126)、对照(2.819)、补播+施肥(1.494);均匀度指数大小依次为封育+施肥(0.902)、对照(0.865)、补播+施肥(0.582);群落总盖度大小依次为封育+施肥(85.9%)、补播+施肥(79.7%)、对照(72.9%);补播+施肥+封育处理后地上生物量最大(460.65 g/m2),原生植被+封育+施肥处理居中(310.14 g/m2),对照最低(178.96 g/m2);地下生物量大小依次为封育+施肥(6 920.37 g/m2)、补播+施肥(1 458.96 g/m2)、对照(828.91 g/m2);补播+施肥+封育处理优良牧草较对照提高近50倍,杂草类减少82.81%,封育+施肥处理较对照良牧草比例提高48倍,杂草类比例减少80.46%.半人工草地通过灭除杂草和施肥相结合的示范试验表明:单纯进行灭杂,地上生物量减少,灭杂和施肥相结合不仅可提高地上生物量,而且可提高优良牧草的比例;不同处理区土壤养分含量各不相同,其中封育+施肥处理全氮、全碳、有机碳最高,对照居中,补播+施肥较低.
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目的通过观察藏药7号水提液对大鼠离体胸动脉条收缩作用的影响,研究藏药7号的降压机制.方法以生理盐水作为对照组,观察藏药7号水提液(6 g/L)和维拉帕米(Ver 0.013 g/L)对高K+液引起的主动脉条收缩的时效影响,观察对KCl、NE及CaCl2引起的大鼠主动脉条收缩的量效曲线的影响,以及对NE引起的依赖于细胞内钙及细胞外钙收缩的影响.结果藏药7号水提液抑制高K+液引起的主动脉收缩(P<0.001);而且可以使KCl、NE及CaCl2引起的大鼠主动脉条收缩的量效曲线非平行右移,最大效应降低,呈非竞争性拮抗作用(P<0.05);与维拉帕米相似,并且对NE引起的依赖于细胞内钙及细胞外钙的收缩均有抑制作用(P<0.05).结论提示藏药7号的降压机制与钙离子通道拮抗剂一致,而且其作用效果比Ver平稳,其最大作用与Ver相近.
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目的 通过对比观察藏药1号与藏药7号水提液对大鼠离体胸动脉条收缩作用的影响,研究藏药1号与藏药7号的降压机制。方法 以生理盐水作为对照组,观察藏药1号与藏药7号水提液(6mg/ml)和维拉帕米(Ver 0.013 mg/ml)对高K~+液引起的主动脉条收缩的时效影响,观察对KCl,NE及CaCl_2引起的大鼠主动脉条收缩的量效曲线的影响,以及对NE引起的依赖于细胞内钙及细胞外钙的收缩的影响。结果 藏药1号与藏药7号水提液抑制高K~+液引起的主动脉收缩(P<0.001);而且可以使KCl,NE及CaCl_2引起的大鼠主动脉条收缩的量效曲线非平行右移,最大效应降低,呈非竞争性拮抗作用(P<0.05),与维拉帕米相似,并且对NE引起的依赖于细胞内钙及细胞外钙的收缩均有抑制作用(P<0.05)。从pD'2值分析,藏药1号的药效作用要强于藏药7号,但比Ver的弱。结论 提示藏药1号与藏药7号的降压机制与钙离子通道拮抗剂一致,而且其作用效果比Ver延迟、平缓,其最大作用与Ver相近。而且藏药1号药效更加显著。
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本文在分析、归纳、综合的基础上作出了7自由度机械臂的图谱.包括位置空间、奇异空间、回避障碍和回避奇异等问题.给出了一种普遍适用的方法.并介绍了该方法的使用,对7自由度机器人的结构设计和选型有一定的参考价值.
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To investigate the changes in the chemical weathering intensity of dust source region in Asia continent, ~(87)Sr/~(86)Sr ratios of acid-washed residues from the loess deposits in China and Tajikistan were analyzed, respectively. The results and conclusions are listed as below. 1. The oscillation of ~(87)Sr/~(86)Sr ratios of acid-insoluble residues in the Chinese Loess Plateau was mainly attributed to the chemical weathering intensity of the source region and the grain size. Counteracted the effect of particle size, the calibrated 87Sr/S6Sr ratio can be used as a proxy for the chemical weathering intensity of the source region. 2. The Sr/ Sr ratios of red clay-loess sequence from the Loess Plateau indicate that the chemical weathering intensity of the dust source region between 7.0 and 2.6 Ma is stronger than that in the Quaternary period. This also suggests a general decline in chemical weathering intensity of the source region from 2.6 Ma to the present. Such pattern is more remarkable since 1.0 Ma BP. 3. The ~(87)Sr/~(86)Sr ratios of the Tajik loess during 0.8-1.8 Ma is much more higher than those from 0.8 Ma to the present. This implies that the chemical weathering intensity of the source region in Central Asia is much stronger during 0.8-1.8 Ma than the period since 0.8 Ma. 4. The record of Sr isotope ratios from both sections shows an accelerating course of aridity of the Asian dust source region over the Quaternary period.
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为了解高温高压条件下,α-β石英相变过程中的弹性性质,在0.7~1.8GPa,室温~1120℃条件下,利用多顶砧波速测量装置,采用脉冲反射-透射法,测量了α石英以及相变为β石英的纵波速度,弹性纵波穿过单晶α石英的方向为平行结晶轴X方向。实验结果表明,随温度升高,α石英的纵波速度开始非线性降低,之后,快速升高,这一现象是由于α-β石英相变引起的,依据晶体对称性与弹性参数的关系确定了α石英的弹性参数(C_(11)),及其随温度和压力的变化关系,同时获得了β石英的弹性参数(C_(11)),实验证实,测量α-β石英相变时的纵波速度,不仅是确定α-β石英相变温度和压力的一种方法,也是校正高压腔体温度和压力的有力手段.
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峨眉山大火成岩省二滩地区玄武岩W(SiO2)/%=40.5~59.65;普遍高碱,w(K2O+Na2O):2.64%~7.67%。W(TiO2):2.10%~6.53%,Ti/Y〉500,该区玄武岩属于高钛(HT)型玄武岩;其Mg^#:58~84,明显高于高于宾川高钛玄武岩(31~53),说明岩浆演化程度明显低于宾川高钛玄武岩浆。岩石样品中Sr显示明显负异常,暗示了二滩玄武岩经历了广泛的斜长石结晶分离;而Eu不显异常,则反映了玄武岩岩浆中有高Eu^3+/Eu^2+比值的存在,其环境为氧化环境。在二滩玄武岩和宾川高钛玄武岩中,Ni,Zr,TiO2和Mg^#均显示了明显差异,说明二滩玄武岩具有独立的地球化学特征。二滩玄武岩不相容元素(Rb,Ba,Th,U,Nb,Ta,La,Ce等)配分曲线与OIB相似,及其Ta/Yb vs Th/Yb双变量图解也显示出了富集地幔特征,这些特征反映了峨眉山二滩玄武岩源区为富集地幔源,玄武岩岩浆可能为地幔柱物质。此外,Ba/Th,Zr/Nb,La/Nb,Ba/Nb等比值介于EMI OIB和EMII OIB之间,以及Ce/Pb比值也说明:二滩玄武岩缺少HIMU OIB端元组分,是EMI OIB和EMII OIB两端元的混合产物。
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云南白马寨镍矿区煌斑岩全部为云煌岩.两个样品的^40Ar/^39Ar定年结果分别为32.46±0.62Ma和32.01±0.60Ma,表明矿区煌斑岩为哀牢山断裂带新生代早期高钾岩浆活动的产物.在化学组成上,矿区煌斑岩具有高M值[100×Mg/(Mg+Fe^2+)](67.42~86.35)、高ALK(K2O+Na2O为7.01%~9.81%)、富钾(K2O/Na2O为1.66~2.64)、富大离子亲石元素(如Sr、Rb、Ba等)和LREE、明显的Ta、Nb、Ti负异常的特征.Sr-Nd同位素具有高(^87Sr/^86Sr)0比值(0.70625~0.70912)和低εNd(-5.22~-3.68)的特征,位于EM1和EM2地幔端元之间,有更靠近EM2的趋势.元素和同位素地球化学特征表明矿区煌斑岩的源区为交代富集地幔,进一步判别表明源岩处于尖晶石相方辉橄榄岩和石榴石相二辉橄榄岩的混合线上,以尖晶石相方辉橄榄岩为主.源区交代富集的矿物既有金云母,也有角闪石.岩浆演化过程中经历了橄榄石+斜长石±磷灰石±铁钛氧化物的结晶分异.岩浆形成于大陆弧的构造背景,俯冲的陆壳和古特提斯洋壳对富集的源区均有贡献.白马寨镍矿区煌斑岩和哀牢山断裂带新生代早期其它高钾岩浆岩具有相近的年代、一致的地球化学特征,表明它们具有相似的源区,受控于相同的构造背景.
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创造力发展的年龄特征一直是研究者非常关注的问题。很多研究者认为,只有更全面地探查儿童创造力的发展,才能充分了解创造力的本质,所以,应该在多个领域中研究创造力。本研究以文学领域中儿童比较熟悉并喜欢的讲故事的形式,采用同感评估技术(CAT),对4-7岁儿童的创造力发展趋势进行了研究,并深入探讨了经常被人们提到的出现在该阶段中的“入学突降”现象。研究共分为两个部分:研究一考察了4-7岁儿童创造力的发展趋势和创造力的“入学突降”现象;研究二探查了讲故事任务的创造力与言语能力的关系,讨论了创造力的领域特殊性。研究结果发现: 1. 4-7岁儿童的创造力随年龄的增长总体上表现出先上升后下降的趋势,并且存在性别差异。性别差异的具体表现为,女生在4-5岁的发展快于男生,且在6岁开始出现下降趋势。 2. 排除入学影响,随年龄增长,6-7岁儿童的创造力显著上升。 3. 6岁已入学儿童的创造力显著低于同年龄未入学儿童,其中女生受到的影响更大。 4. 言语能力是讲故事创造力的基础,只有达到了一定水平的言语能力才能够表现出较高水平的创造力,但是言语能力只是讲故事创造力的必要而非充分条件。 5. 研究结果部分支持了创造力领域特殊性的理论。
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儿童的故事重述涉及工作记忆和抽象表征能力,是与儿童的日常学业任务密切联系。儿童能否把握时间线索来组织故事重述,反映的是儿童抽象出故事事件内在时间关系的能力,因此对儿童故事重述的探查可以揭示儿童抽象思维发展的一般规律和特点。本研究在前人研究的基础上,系统探查了7-11岁儿童故事重述能力及其策略的发展过程,探讨了时间线索对儿童故事重述的影响,并对ADHD儿童和正常儿童的故事重述及策略进行了比较。 主要研究结果如下: (1)7-11岁儿童故事重述能力总体上随年龄增长而提高,按正确顺序重述的事件数量增多,重述过程中提取和使用的时间线索也增加。其中7-9岁有较快速的发展。 (2)随故事中包含的事件数量的增加,故事难度增大,儿童的故事重述成绩有所下降,故事长度对7岁和9岁儿童的影响大于对11岁儿童的影响。 (3)有、无时间线索语词会影响儿童的故事重述。故事中包含时间语词线索有助于儿童的故事重述。11岁儿童的故事重述已不受有、无时间线索的影响,他们在无时间线索的条件下,更多地主动使用表示因果关系的语词来表征事件关系。 (4)ADHD儿童的故事重述能力在9岁到11岁有较快的发展。但总体而言,ADHD儿童对含有时间线索故事的重述能力显著差于正常儿童。 (5)故事再学习对ADHD儿童和正常儿童的故事重述都存在促进作用。但ADHD儿童故事再学习效果不如正常儿童,低龄儿童中差距尤其明显,随着年龄的增加,ADHD儿童与正常儿童故事再学习效果的差距逐渐缩小。 (6)不同年龄的儿童主要采用四种策略解决问题。随年龄增长,正常儿童和ADHD儿童中使用水平较高的内容主线和逻辑关系策略的人数都有所增加。但ADHD儿童中高水平策略使用人数比例仍低于正常儿童。
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Children’s understanding of deontic rules and theory of mind (ToM) were the two research domains for children’s social cognition. It was significant for understanding children’s social cognition to combine the researches in the two domains. Children at 3, 5 and 7years were required to answer three questions according to the stories which happened in children’s familiar context. The three questions were designed to address the three problems:⑴Development of 3-7-Year-old children’s understanding about how the deontic rules were enacted or changed.⑵ Development of 3-7-Year-old children’s understanding about that the deontic rules and the actor’s mental states could impact on his behaviors.⑶ Development of 3-7-Year-old children’s capacity to integrate the deontic rules and mental state to evaluate the actor’s behavior. The results showed that: ① The 3-7-Year-old children had known that deontic rules were established by the authority’s speech act. But there were still some irrelevant factors which influenced the children’s judgments, such as the authority’s desire. ② The children gradually recognized the relationship between actors should do something and they will do the same thing. 3-year-old children could recognize such relationship in a way, but their predictions were usually influenced by some irrelevant factors. The children at 5 and 7 years old understood this relationship more steady. ③ In deontic context, more and more children predicted the actors’ behaviors according to the actors’ mental states as they grown up. The ratio that the 3-7-Year-old children predicted the actors’ behavior according to their false belief about the deontic rules was smaller in deontic context compared with the children’s performance in traditional false belief task. This maybe indicated that the deontic context influenced the children’s inference stronger than the physical context. ④ When they could get the actors’ desires and the deontic rules, all the children could predict the actors’ behaviors according to their desires, but not the deontic rules. It meant that all the children could understand that the actors’ desire mediated between the deontic rules and their behaviors. But when the actors wanted to transgress the deontic rules, all the children’s predications became less accurate. ⑤ When they assigned criticism, more and more children could discriminate different behaviors as a result of diverse mental states although they all transgressed the deontic rules. But the most part of children overweighed the deontic rules but overlooked the actors’ mental state about the deontic rules; their criticism to behaviors which transgressed the deontic rules just differ in quantity according to diverse mental states, that is: if the actors known the rules or want to transgress the rules, then punished more, and if the actors didn’t know the rules or transgress the rules accidentally, then punished a little.