987 resultados para 368


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利用超临界CO_2萃取唐古特白刺籽油,并对籽油进行了GC/MS分析。实验确定的最佳超临界CO_2流体萃取条件是:萃取温度45℃,萃取压力20 MPa,CO_2流量为35-40 kg/h,萃取时间120min,在此条件下白刺籽油的萃取率为15.11%。利用GC/MS对白刺籽油分析,发现其不饱和脂肪酸的相对含量高达93.37%。比较了超临界CO_2萃取白刺籽油油样和石油醚萃取白刺籽油油样的理化性质,发现超临界CO_2流体萃取的籽油质量优于传统溶剂萃取的籽油。

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大通河流域共有野生种子植物77科、368属、1 154种.分别占本区所属的青藏高原植物亚区唐古特地区总科数的85.56%、总属数的72.44%、总种数的50.50%.区系特征如下:(1)本区是唐古特地区一个值得提倡大力保护的植物模式标本的集中产地,种类相对较丰富.(2)属的分析表明,本区属于以北温带成分,特别是欧亚大陆温、寒地带典型成分为优势的,兼具温性、寒温和高寒类型的温带区系性质.(3)区系具有年轻和衍生的性质.具体表现在木本类型较少,多年生草本多,缺乏古老的和原始的类群,一些中国特有属种为衍生类群.(4)作为青藏高原的边缘地带和过渡区系,本区系在受到我国华北区系和西南高山区系的双重影响的同时,保持了其高原、高山类型的区系性质.(5)为我国黄土高原植物区系向青藏高原植物区系过渡的代表区系之一.本文的分析表明,在中国种子植物区系分区中,本区属于青藏高原植物亚区中的唐古特地区.

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对青海海北地区高山草甸主要植物群落小嵩草(K obresia pygmaea) 草甸、矮嵩草(K. humilis) 草甸、藏嵩草(K. tibetica) 沼泽化草甸地上生物量动态和能量分配的研究结果表明, 不同植物群落年地上净生产量及其年际动态和主要植物类群生物量季节动态具明显的差异, 其生物量季节动态可由如下模型表示: W i = Ki/(1 + exp (A i - B it) )   植物群落地上、地下生物量的垂直分布呈典型的金字塔和倒金字塔模式。小嵩草草甸、矮嵩草草甸和藏嵩草沼泽化草甸的地上净生产量依次为368.4g·m – 2·a- 1、418.5 g·m – 2·a- 1和518.4 g·m – 2·a- 1, 所固定的太阳能值依次为6655.16kJ·m – 2·a- 1、7610.09 kJ·m – 2·a- 1、9488.77 kJ·m – 2·a- 1。光能利用率分别为0.1097%、0.1256%、0.1568%。

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对栖居于青海高原的根田鼠(Microtus oeconomus)于冷驯化(5℃)1、7和 21天的非颤抖性产热(NST)、褐色脂肪组织(BAT)和肝脏的组织蛋白和线粒体蛋白含量、心脏和肌肉的线粒体蛋 白含量、四种组织线粒体的细胞色素氧化酶活力及肝脏线粒体的状态Ⅵ呼吸能力等指标进行了测 定。结果表明:冷驯化过程中NST趋于增加,有一个逐渐发展的过程;BAT线粒体蛋白含量对低温的反应比组织蛋白的反应剧烈,肝脏、心脏和肌肉组织的线粒体蛋白含量变化较温和,但各种组 织的细胞色素氧化酶活力随冷驯化而急剧增加,肝脏线粒体的状态Ⅵ呼吸能力加强。结果说明 NST在低温下的热能调节过程中占十分重要的地位,肌肉、心脏、肝脏等组织也参与了体温调节过程。在自然生境中,低温是一重要的刺激调节因子。

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疏水作用色谱是色谱学科的一个分支。它与反相色谱一样都具有疏水性的特点。因此, 疏水性活性蛋白在疏水柱上比较强的保留, 而亲水性的活性蛋白不保留或保留很弱。采用盐溶液作为流动相, 在疏水柱上活性蛋白不会产生不可逆吸附, 活性蛋白的三维结构不被破坏, 失活率低, 一般不超过, 所以, 高效疏水作用色谱对活性蛋白的分离和测定是比较理想的方法。疏水作用色谱无论在填料的合成上还是在应用上都在发展中。我们用疏水作用色谱对高原春小麦的淀粉酶进行了分离和活性的测定。

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A study was conducted on grass mixtures that included smooth bromegrass (SB) + drooping wild ryegrass (DW), smooth bromegrass + Siberian wild ryegrass (SW) + crested wheatgrass (CW) and smooth bromegrass + Siberian wild ryegrass + drooping wild ryegrass + crested wheatgrass in the alpine region of Qinghai-Tibetan Plateau. The study was conducted from 1998 to 2000 to investigate the effects of N application rates and growing year on herbage dry matter (DM) yield and nutritive values. Herbage DM production increased linearly with N application rates. The effect of N application on DM yields was greater (P < 0.05) in the 2nd and 3rd production years than in the establishment year. Dry matter yields of SB + SW + CW and SB + SW + DW + CW can reach as high as 15 000 kg ha(-1) at 345 kg ha(-1) N rate in the 3rd growing year. With increased N application rates, crude protein (CP) contents and 48 h in sacco DM degradability of grasses increased (P < 0.05). No effect (P > 0.05) of N application was detected on organic matter (OM) and acid detergent fibre (ADF) concentration. It can be concluded that for increased biomass production in the alpine region of the Qinghai-Tibetan Plateau, a minimum of 345 kg N ha(-1) should be applied to grass stands in three split application of 115 kg N ha(-1), in early June, early July and late July

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为具有前轮导向的牵引车-拖车提出了一种最优控制法.这种最优控制法是基于位置误差和方向误差及导向角的二次性能指标为最小.

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贵州茂兰喀斯特原始森林地区25个雨水样品的化学组成研究表明,该区雨水的pH值为4.4~7.2,平均为5.1。雨水样品富NH4^+、Ca^2+和SO4^2-、C1^-。NH4^+是最主要的阳离子,平均值为56.8/μmol/L,占阳离子组成的26%~74%,Ca^2+次之,平均值为14.8μmol/L,NHg和Ca^2+之和占了阳离子组成的71%~94%,SO4^2-是最主要的阴离子,平均值为39.2μmol/L,占了阴离子组成的69%~91%,CI一次之,平均值为9.5μmol/L。SO4^2-和C1-占了阴离子组成的71%~96%。与中国其他地区的雨水样品相比,茂兰地区雨水离子含量要低1~2个数量级;物质来源分析表明茂兰地区雨水中溶质主要来源于自然过程的输入,人为活动输入可以忽略不计.

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利用多元统计分析方法对广西来宾铁桥剖面栖霞组层纹灰岩和江西慈化洪桥剖面栖霞组粒泥灰岩的岩石地球化学特征进行了分析;对广西来宾铁桥剖面栖霞组的灰岩样品40件及该剖面中产出的菊花石样品8件、江西慈化洪桥剖面的粒泥灰岩样品8件、浏阳永和剖面的灰岩样品10件及该区产出的菊花石样品3件进行了黄铁矿矿化程度(DOP值)的测定分析,分析结果表明华南地区的DOP值多数大于0.42;结合岩石微量元素比值特征的分析,表明华南地区栖霞组灰岩形成于缺氧的沉积环境。DOP值的变化趋势为:浏阳>来宾>慈化,表明华南地区3个剖面的沉积环境含氧量的关系为:浏阳<来宾<慈化。DOP值在3个剖面上的周期性变化与剖面中的沉积旋回相对应,亦表明沉积环境的含氧量呈周期性变化。

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本文通过对俄罗斯Streltsovka火山岩型铀矿床和中国相山火山岩型铀矿床的对比研究,发现两矿床具有相似的成矿构造控制特征:走滑挤压至拉张伸展的构造转化是矿床形成的有利构造机制;盆地格网状断裂构造对铀的成矿起着导矿、控矿和容矿的作用;多次构造叠加形成的独特的盆地二元结构是成矿的有利因素.根据对这些构造控制特征的分析,提出了火山岩型铀矿床找矿勘探的几点建议.

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在前人工作基础上,侧重研究石英脉型金矿床成矿的地质背景,建立了该类型金矿的成矿模式。进而开展三轴温压条件下的成岩成矿实验,构造形变特征及其与成矿物质活化、迁移、富集之间的相互关系的模拟实验。实验结果表明:(1)该区岩石、矿石在高温高压条件下,产生塑性变形(褶皱)和脆性变形(破裂);(2)在变形过程中使成矿物质活化、迁移和富集,形成顺层及穿层的含金石英脉,并在多期多次变形过程中使成矿物质叠加富集;(3)在褶皱(背斜)轴部形成富矿体。模拟实验结果与所建立的该类型金矿构造控矿和成矿模式非常相似。实验资料的力学分析表明,由轴压所产生的构造附加压力大大地提高了实际围压,从而促进了岩石流变、变形和物质的迁移,由此促进含矿流体向构造附加压力小的部位定向迁移、充填和成矿。构造附加压力是促进该区金成矿的重要动力条件.

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北欧和北美的研究发现水库是典型的汞敏感生态系统,新建水库而引起的鱼体甲基汞污染问题已受到科学家的高度重视,而我国在这方面的研究比较薄弱。本论文选择乌江流域的6个水库作为研究对象,并根据年龄把这些水库划分为3个演化阶段,洪家渡、引子渡、索风营水库为初级演化阶段,普定、东风水库为中级演化阶段,乌江渡水库为高级演化阶段。对这6个水库总汞和甲基汞的输入和输出通量进行了研究,探讨了不同演化阶段的水库对总汞和甲基汞的“源/汇”作用,主要研究内容有以下三个方面:(1)各水库入出库河流中汞的分布特征;(2)大气降水中汞浓度及沉降通量的分布;(3)乌江流域不同水库汞的输入输出通量。通过本论文的研究,得出以下主要结论: 1. 乌江流域河流中总汞、颗粒态汞、溶解态汞、活性汞、总甲基汞、溶解态甲基汞的年均浓度分别为3.41±1.98、2.05±1.73、1.36±0.44、0.24±0.11、0.15±0.06、0.08±0.03 ng•L-1。与国内外其它河流的比较发现,总汞的浓度明显低于国外受污染的河流,略高于国外未受污染的河流。溶解态汞、活性汞、甲基汞的浓度略低于受污染的河流,与未受污染的河流基本相当。与同处在贵州喀斯特地区的阿哈湖、红枫湖、百花湖的入出库河流相比,总汞、溶解态汞、活性汞、甲基汞、溶解态甲基汞的浓度均明显偏低。 2. 水库的修建显著降低了出库河流中总汞、颗粒态汞的浓度,使总甲基汞和溶解态甲基汞的浓度升高,而且增加了出库河流中溶解态汞、活性汞、总甲基汞占总汞的比例。不同形态汞的沿程分布显示,梯级水库的修建改变了河流原有的汞的生物地球化学过程,使乌江多个河段的甲基汞升高,并且随着水库生态系统的不断演化,水库输出的甲基汞将增加,下游河流水体中甲基汞有继续升高的趋势。 3. 大气降雨中总汞、溶解态汞、颗粒态汞、活性汞、总甲基汞的浓度分别为7.49~149 ng•L-1、1.23~10.0 ng•L-1、5.76~142 ng•L-1、0.56~2.94 ng•L-1、0.08~0.82 ng•L-1,且以颗粒态汞为主,约占总汞比例的87%。总汞、溶解态汞、颗粒态汞、甲基汞的浓度有明显的季节变化趋势,冬春季高于夏秋季,而空间分布特征不明显。2006年总汞、甲基汞的年湿沉降通量为34.7±5.80 µg•m-2•yr-1、0.18±0.03 µg•m-2•yr-1,且主要受降雨量的影响。乌江流域降雨中总汞的浓度及其湿沉降通量远高于北美和日本,低于中国的一些城市地区(如长春和北京),而甲基汞的浓度和通量与其它地区相当。 4. 在乌江流域的不同水库中,降雨输入总汞和甲基汞的通量主要受降雨量和水库面积的影响,而与降雨的汞浓度间没有相关性。河流向水库输入总汞的量主要受河流流量的控制,而输入甲基汞和颗粒物的量受河流流量和浓度的影响。下泄水输出总汞、甲基汞、颗粒物的通量受浓度和流量的影响。由于流域面积/水面面积的比值较大,水库水量、总汞、甲基汞、颗粒物的输入以河流为主,分别占总输入的87%、80%、85%、86%。输出以下泄输出为主,下泄水输出的水量、总汞、甲基汞、颗粒物分别占总输出的80%、77%、86%、79%。 5. 从输入-输出通量的结果发现,各水库均表现为河流颗粒物输送的“汇”;除乌江渡水库外,其它水库均表现为总汞的“汇”;对甲基汞而言,引子渡、洪家渡、索风营水库表现为“汇”,而普定、东风、乌江渡水库则表现为“源”。 6. 普定和洪家渡水库中总汞的贮存率为56%和57%,明显高于其它水库,说明在上游有水库存在的情况下,水库对总汞“汇”的作用将降低。普定、东风、乌江渡水库中甲基汞的净通量分别为+69.4 g•yr-1、+368 g•yr-1、+857 g•yr-1,转化率为13%、73%、84%,说明甲基汞的净通量和转化率与水库的演化阶段有关,随着水库演化阶段的升高而增加,并且随着水库的不断演化,甲基汞将从“汇”变成“源”。

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To study the relationship between mental-physical health and coping behavior,job stress and job motivation in medical laboratory scientists and technicians. A cross-section survey was conducted,using the anxiety rating scale(SAS), depression rating scale(SDS), coping behavior rating scale,self-rating subhealth scale,self-rating stress scale,and self-rating job motivation scale among 289 medical laboratory scientists and technicians with analysis of ANOVA and Regression. The study was carried out in three steps:step1 is to analyze the general situation of the mental-physical health.Step 2 is to analyze the features of the main influencial facotors.Step 3 is to study the influence of the relative factors on mental-physical health.The following are the results: 1.The anxiety and depression scores of the medical researchers and technicians were 30±6 and 37±8 respectively,both significantly lower than those of the national norm(34±6 and 42±11 respectively,both P<0.01),which are of significant difference. The depression score of the associate chief technician was 42±7, significantly higher than those of the medical researchers and technicians with any other professional titles (all P<0.05), and the anxiety score of the associate chief technicians was 32±7, significantly higher than that of the research fellows(28±4, P<0.05),with no significant difference to the score of the medical researchers and technicians with other professional titles. The depression score,anxiety score and the subhealth score of the age group of 36~49 were 39±9,31±7 and 32±9 respectively, both higher than that of the age group of 20~35 (36±8,29±6 and 29±7 respectively,both P<0.05),while there is much diference among other age groups. And the subhealth status has nothing to do with marital status,education background and professional titles. 2.The coping behaviors,job stress and motivation of the military medical laboratory scientists and technicians. 1)Coping behaviors:The seeking help score of the associate chief technicians was 2.8±0.5,not significantly different from that of the associate research fellows(2.8±0.5),but significantly lower than those of the medical researchers and technicians with other professional titles(all P<0.01),and whose self-blame score was higher than that of the research fellows,which is of significant difference.The self-blame score and the imagination score of the associate research fellows were 2.0±0.5 and 2.4±0.5 respectively, significantly higher than that of the research fellows(1.6±0.4, 2.1±0.4,both P<0.01). The seeking help score of the females was 3.1±0.5, significantly higher than that of the males(2.9±0.5, both P<0.01),and the solving problem score was 3.4±0.6,significantly lower than the male(3.6±0.7, both P<0.01).There is no any significant difference in coping behaviors among researchers and technicians of different marital status,education background and age groups. 2)Job stress: The score of job stress of the age group of 35~49 and 50~60 were 23±8 and 25±6 respectively,significantly higher than that of the 20~35(21±7,both P<0.05). There is no any significant difference in job stress among researchers and technicians of different marital status,gender,professional titles and education background. 3)The score of meeting personal desire for reputation and interests of the males was 19.6±5.4,significantly higher than that of the females(18.4±5.0, both P<0.05), while there is no significant difference in job motivation among researchers and technicians of different titles,education,age and marital status. 3.The relationship of the mental-physical health of the military medical laboratory scientists and technicians with their coping behaviors,job stress and motivations 1) Coping behaviors:Regression analysis showed that, the best predictors of subhealth were anxiety,depression and escaping (β=-0.40,β=0.23, β=0.14, both P<0.01).the best predictors of anxiety and depression were active coping behaviors and negative coping behaviors (β=-0.40,β=0.40, both P<0.01).The moderate(rational) coping behaviors is the best predictor only of anxiety and of significant difference. 2)job stress : Regression analysis demonstrated that anxiety,depression,job stress 2 and job stress 4 are the best predictor for subhealth;job stress 12 is the best retro-predictor for depression; job stress 3 and 8 are the best predictor for depression;and job stress 2 and 9 are the best predictor for anxiety ,which are of significant difference. 3)Motivation:Regression analysis demonstrated that depression is the best predictor for subhealth while motivation itself doesn't predict subhealth;with respect to the specific contents of motivation,"probing unknown rules and making contributions to the human society "is the best retro-predictor for depression and has nothing to do with anxiety prediction. 4) The combined influences of coping behaviors,job stress and motivations: Regression analysis showed that, the best predictors for subhealth were anxiety,depression and job stress(β=0.41,β=0.24, β=0.19, both P<0.01).the best predictors for anxiety and depression were active coping behaviors and negative coping behaviors (β=-0.40,β=0.40, both P<0.01).The moderate(rational) coping behaviors is the best predictor only for anxiety and of significant difference. CONCLUSIONS: Regression analysis showed that the best predictors for anxiety and depression were active coping behaviors and negative coping behaviors, the best predictors for subhealth were anxiety,depression and job stress.Coping behaviors, job stress and motivations have significant influences on the mental-physical health of the military medical researchers and and technicians. Among them,coping behavior is the most important factor while job stress and motivation follow. Seeking help more often,less self-blame ,imagination and job stress could help release the anxiety, depression and improve the subhealth of the medical researchers and technicians. The findings of this study indicate we should address the physical and mental health of the military laboratory researchers and technicians.