181 resultados para 331-C0016A


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【目的】验证饱和链烷技术测定家畜食性和食量的精确性,确定绵羊粪便中链烷的回收率。【方法】于2004年秋季在中国科学院内蒙古草原生态系统定位研究站用不同放牧演替阶段的优势植物羊草(Lcymus chincnsis)、糙隐子草(Cleistogenes squarrosa)和冷蒿(Artemisia frigide)按一定比例混合组成日粮,饲喂9只2岁羯羊,每只羊投喂一粒QSM胶囊,试验期内每天记录绵羊实际牧草采食量、采食成分和排粪量,利用气相色谱分析牧草和粪样的链烷含量,应用链烷技术测定绵羊的排粪量、不同牧草呆食比例和总干物质采食量,并与实际值进行比较。【结果】3种牧草链烷模式存在种间差异;绵羊粪便中链烷的回收率随链烷长度的增加而线性增加;绵羊排粪量测定值与实际值存在极显著的正相关(P〈0.01,r=0.9994);绵羊采食羊草、糙隐子草和冷蒿比例的测定值与实际值存在极显著(P〈0.01)正相关,相关系数分别为0.9913、0.9864和0.9999;绵羊干物质采食量用C33:C32和C31:C31比值测定的值分别比实际值低4%(±1.3%)和7%(±1.3%),但差异不显著(P〉0.05)。【结论】饱和链烷技术可以精确测定典型草原绵羊的排粪量、食物组成和采食量。

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采用C18反相柱高效液相色谱方法分离、外标法定量对大黄属掌叶组唐古特大黄、波叶组波叶大黄、穗序组穗序大黄的根(及根茎)、叶片、叶柄、主茎四部分的芦荟大黄素、大黄酸、大黄素、大黄酚4种游离和结合蒽醌的含量进行了测定和比较。结果表明:唐古特大黄中,叶片中的游离蒽醌含量高于其它部分,游离蒽醌总量地上部分远高于地下部分;结合蒽醌则根中最高,蒽醌总量地下部分远高于地上部分。波叶大黄和穗序大黄中,游离和结合蒽醌均为根中最高,穗序大黄蒽醌总量地下部分远高于地上部分,而波叶大黄中,游离蒽醌总量地上部分高于地下部分,结合蒽醌总量地上部分与地下部分相差不大,地上部分略高于地下部分。

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The effect of feeding 0, 4, 8 and 16% rapeseed oil from 12-42 days of age was studied in broiler chickens on performance, digestibility of nutrients, and development of gastrointestinal tract, protein and energy metabolism. Thirty six female chickens (Ross 208) with initial body weight average 246 g were allocated to the four groups and kept pair-wise in metabolism cages. The chickens were fed similar amounts of metabolisable energy (ME) per day and similar amounts of essential amino acids relative to ME by adjusting with crystalline amino acids. The chickens were subjected to four balance periods each of five days with two 24 h measurements of gas exchange in two open-air-circuit respiration chambers inserted on the second and third day of each period. The addition of rapeseed oil increased the amount of gutfill indicating a reduced rate of passage and causing a hypertrophy of the gastrointestinal tract. There was a positive effect on feed utilisation as well as on digestibility especially of dietary fat together with higher utilisation of protein with addition of rapeseed oil. The partial fat digestibility of rapeseed oil estimated by regression was 91.1% and the partial metabolisability (ME/GE) of the rapeseed oil was estimated to 85% yielding an apparent metabolisable energy value of 34.30 MJ/kg.

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Milula, a monotypic genus endemic to the Qinghai-Tibetan Plateau, was found to be nested deeply within Allium by the molecular phylogeny despite the aberrant morphology. It remains unknown what had contributed to the rapid evolution of morphology and origin of this exceptional species. In contrast to a previous report of its karyotypes with 2n = 16 = 8M+8SM (2SAT), similar to most species of Allium, a rather different karyotype, 2n = 20 = 4M +10SM+6T (2SAT), was found in examined 31 individuals from 6 populations of M. spicata distributed in the central Tibet. Karyotypes of 7 Allium species occurring in the Qinghai-Tibetan Plateau were further reported. The basic number x = 8 was confirmed for all of them and their karyotypes consist mainly of metacentric and submetacentric chromosomes with rare subterminal and terminal chromosomes. The karyotype of M. spicata is distinctly different from that of most Allium species occurring in the plateau through a complete comparison of all available species in this region and adjacent areas. However, the same chromosome number and similar karyotypic structure were found in A. fasciculatum of Sect. Bromatorrhiza, indicating a possible close relationship between them. But this similarity is contradictory to the preliminary molecular phylogenetic analysis that Milula was closely related to A. cyathophorum of Sect. Bromatorrhiza with x=8, but the other species with x=10 and 11 in this section were clearly placed in the other clade. We therefore suggested that the paralleling evolution from x=8 to x=9, 10 and 11 with increasing asymmetry of karyotype possibly due to the chromosomal Robertsonian translocation might occur separately in the two recognized phylogenetic lineages of Allium. In addition to aneuploidy and following change of the chromosomal structures, the habitat isolation due to the recent uplift of the Qinghai-Tibetan Plateau and the Quaternary climatic oscillation, plays a greater role in origin of Milula and other endemic species (genera) with aberrant morphology from their progenitors.

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Forage selection plays a prominent role in the process of returning cultivated lands back into grasslands. The conventional method of selecting forage species can only provide attempts for problem-solving without considering the relationships among the decision factors globally. Therefore, this study is dedicated to developing a decision support system to help farmers correctly select suitable forage species for the target sites. After collecting data through a field study, we developed this decision support system. It consists of three steps: (1) the analytic hierarchy process (AHP), (2) weights determination, and (3) decision making. In the first step, six factors influencing forage growth were selected by reviewing the related references and by interviewing experts. Then a fuzzy matrix was devised to determine the weight of each factor in the second step. Finally, a gradual alternative decision support system was created to help farmers choose suitable forage species for their lands in the third step. The results showed that the AHP and fuzzy logic are useful for forage selection decision making, and the proposed system can provide accurate results in a certain area (Gansu Province) of China.

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基于捷联惯导系统(INS)与全球定位系统(GPS)定位技术的发展以及机器人导航的需要,本文对INS与GPS的组合导航系统进行了研究。捷联惯导系统与GPS导航各有优缺点,具有互补性,文中将两者结合形成了更加准确可靠的定位系统。本文首先介绍了捷联惯导系统和全球定位系统,并对捷联惯导和GPS的误差作了详细的分析,建立了误差模型。文中应用动力学误差方程建立了九状态INS/GPS综合卡尔曼滤波方程。提出了一种以位置、速度、姿态DCM的误差为状态量,以GPS和INS的位置差作为观测量的INS/GPS组合导航系统的滤波算法,并将该技术应用于机器人的定位导航。仿真实验表明,该算法可有效提高系统导航参数的估计精度。本文分五章对该课题进行了研究。第一章是引言,介绍了课题的研究背景、意义,国内外的研究现状和本文的主要工作;第二章介绍了惯性传感器和GPS接收器的原理和特性;第三章介绍了捷联惯导系统相关的理论知识,包括姿态角的解算,算法具体内容和误差分析,并对捷联惯导系统进行了仿真试验;第四章介绍了Kalman滤波的相关知识并详细介绍了INS/GPS组合导航系统;第五章对INS/GPS组合导航系统的九状态卡尔曼滤波算法进行了仿真,并对试验结果进行了详细的分析。从仿真结果可知,组合导航系统大大的提高了系统的精度,克服了纯惯导系统的缺点。

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笔者等对周潭群沉积变质岩及其中脉体的微量元素、氧同位素地球化学进行了研究, 结果表明, 变质石英脉继承了其围岩的稀土元素及氧同位素地球化学特征, 表明形成石英脉的流体来源于围岩; 脉体的微量元素对Zr—Hf、U —Th、N b—Ta 和Y—Ho 与变质岩有一定的差异, 且有一定的分异, 指示脉体是流体作用的产物。变质流体通过侧向扩散作用形成了周潭群变沉积岩中的变质脉体。

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根据对秦蛉泥盐纪沉积盐地的构造成盆一后期构造变形特征研究,秦岭造山带泥盆纪热水沉积成矿盆地申构造.热流体地质事件可初步厘定如下:① 中泥盆世伸展构造皿盆·热水同生沉积成矿事件(Dt)。@晚混盆世一石炭纪伸展变形一探源热流体叠加事件(D )。@印支期挤压收缩变形·热改造事件(D )。④ 燕山期逆冲推疆构造改造一深糠热流体叠加及脆性变形事件(D.)。@喜玛拉雅山期臆性变形(D )。从盆地热状态及热演化研究角度看-盐地内充填地层体中有机质及矿物可 以记录热状态及热演化历史-利用盆地内充填地层体中有机质及矿物温度计可以反演盆地内充填地层体形成时盆地热状态和盆地底部热流。认为热水沉积成矿盆地热状态及热演化主要研究方向有主要矿物流体包裹体测温、镜质体反射率(风)法、氧同位嘉地质温度计法等。

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为了进一步获得贵州碳酸盐岩风化成土过程的信息,为测定风化成土速率的研究工作奠定基础,本次研究工作通过U-Th的地球化学特征与主量元素、微量元素、稀土元素的地球化学特征的对比研究以及U-Th不平衡来研究贵州两个碳酸盐岩风化剖面的风化成土过程,并得出以下总体认识: 贵州碳酸盐岩风化剖面中的238U-234U-230Th不平衡说明风化剖面中的U-Th不平衡与风化过程密切相关,与风化壳中矿物和铁壳的演化特征密切相关。风化剖面不仅被简单的持续积累或者滤失过程所控制,而且被每一个土层中的复杂的重组过程所影响。U-Th不平衡也说明风化系统的扰动可能与中更新世晚期的气候变化有关。风化剖面中的U-Th不平衡是由母岩碳酸盐岩的风化、风化流体的溶解作用、表土层中的有机质、铁质结核带中的氧化铁矿物以及伊利石、高岭石等粘土矿物对U、Th的吸附作用、α反冲作用以及微生物的还原作用等共同作用的结果。 具体结论如下: (1)两个风化剖面中的U、Th都在半风化层中相对基岩强烈富集,安顺白云岩风化剖面中U、Th在全风化层中下部富集;而遵义石灰岩风化剖面中的U在全风化层中部富集,Th在全风化层上部富集,然后向表土层逐渐减少。 (2)U、Th在半风化层中相对基岩强烈富集,是因为在半风化层中,基岩中的原生矿物发生溶解、蚀变,生成新的次生粘土矿物伊利石,而伊利石对U、Th具有强烈的吸附能力。风化剖面中U、Th的富集主要与地表水的淋滤作用以及铁壳在进一步的风化过程中溶解释放出其中所富集的U、Th,而U、Th向下重新迁移的过程有关。 (3)风化剖面中U、Th的分布特征说明U、Th的含量与风化过程密切相关,与风化壳中的矿物和铁壳的演化特征密切相关。遵义石灰岩风化剖面中U、Th的淋失程度比安顺白云岩风化剖面中U、Th的淋失程度弱也说明了遵义石灰岩风化剖面的风化程度要低于安顺白云岩风化剖面的风化程度。 (4)安顺白云岩风化剖面中,234U/238U在<1和>1之间交替变化。除在剖面中部,230Th/238U≈1外,230Th/238U基本上都>1。 (5)安顺白云岩风化剖面中的238U -234U-230Th不平衡表明:安顺白云岩风化剖面中的U-Th不平衡是母岩碳酸盐岩的风化、风化流体的溶解作用、表土层中的有机质、铁质结核带中的氧化铁矿物以及伊利石、高岭石等粘土矿物对234U、230Th的吸附作用、α反冲作用以及微生物的还原作用等共同作用的结果。 (6)遵义石灰岩风化剖面中234U/238U除少数几个点外,大多数采样点的234U/238U都<1。除了少数几个点外,大部分230Th/238U>1。 (7)遵义石灰岩风化剖面中的238U -234U-230Th不平衡表明:234U-238U不平衡主要是由地表水和入渗水的溶解作用以及α反冲作用为主要的控制机制。而风化剖面中230Th-238U不平衡主要是由表土层中的有机质、高岭石、氧化铁矿物以及伊利石对230Th吸附作用和α反冲作用共同作用的结果。 (8)将U的迁移模型应用于本研究中的两个碳酸盐岩风化剖面,说明这两个风化剖面都被U的近期积累或者滤失过程所影响,风化系统处于过渡的不稳定状态,并通过U在风化剖面中的重新迁移将系统带回稳定状态。 (9)由等时线定年法计算出的安顺白云岩风化剖面的年龄范围为:87.0±7.8-479.2±47.9ka;遵义石灰岩风化剖面的年龄范围为:62.3±8.7-353.3±31.8ka。 (10)由等时线定年法可知:两个风化系统将在~1.1Ma达到稳定状态。 (11)碳酸盐岩风化剖面应用U的迁移模型得出的U的迁移过程与风化剖面中主量元素和微量元素的迁移特征相吻合,说明模型的选择是正确的。 (12)整个风化剖面的238U-234U-230Th不平衡说明风化剖面中的U-Th不平衡与风化过程密切相关,与风化壳中矿物和铁壳的演化特征密切相关。风化系统的扰动可能与中更新世晚期的气候变化有关。碳酸盐岩风化剖面被U的近期迁移过程所影响,风化剖面中的每一个单元甚至每一个土样都具有复杂的历史。这些单元或者土样是古老的风化历史和近期的重新迁移过程的叠加。

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The heat capacities of two Al62.5Cu25Fe12.5 samples containing icosahedral quasicrystals and B2 related crystals respectively were measured with a high-precision automatic adiabatic calorimeter over the temperature range of 75-385 K. The heat capacities of both samples increase with temperature. At the low temperature range, the heat capacity of the quasicrystalline sample is higher than that of the B2 approximate. However, the heat capacity of the B2 sample becomes higher above 254.987 K. (C) 1999 Elsevier Science B.V. All rights reserved.

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The effect of inorganic salts on the hydrolysis of starch in a microwave field was investigated and it was found that some inorganic salts can effectively accelerate the acid hydrolysis of starch. The yield of D-glucose reached 111 wt% (equal to the theoretical yield). (C) 2001 Published by Elsevier Science Ltd. All rights reserved.