974 resultados para Vadianus, Joachim, 1484-1551.
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Reverse phase high performance liquid chromatography (HPLC) was used to separate and quantify aromatic diester-diacids isomers which arise from the opening selectivity of anhydride rings towards methanol. C-13 NMR spectroscopy was a supplementary tool to characterize the isomer structure. It was found that a meta-position attack is slightly preferred in pyromellitic dianhydride (PMDA), while the preferred position of an attack in bridged dianhydrides is determined by the chemical nature (donors or accepters) of the bridged group. The stronger its electron-withdrawing abilities, the lower the probability of a meta-position attack.
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双层类脂膜(BLM)作为生物膜的基本结构主体已被广泛接受。通过掺杂和化学修饰可以改变BLM的特性,并能应用于多种生物膜过程的研究。特别是制成生物传感器和双分子电子器件将有广阔的应用前景。多种有机染料被称作生物着色剂并常用于生物学、生理学、药物学和医学。一般来说,染色和着色过程包括吸附、溶解、渗透和化学反应。但染料如何影响磷脂膜仍然不十分清楚。本文选用用于生物传感器中的生物催化剂Meldola蓝来修饰BLM,并对它的传输性质进行了分析。
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Using three-step laser excitation in an atomic beam and a time-resolved spectroscopy technique, we measured both the lifetimes of the Rydberg levels of Yb I belonging to the perturbed series 6nsp 3P2 and the lifetimes of the perturbing 4f(13)5d(2)6s 3P2, 1D2 levels. An expected shortening has been observed for the lifetimes of those levels which are strongly mixed with the perturbers.
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构建海藻微球体以获得适宜的藻体形态和研究了解微球体系统的光能传输情况以提高光能利用效率,这是实现海藻的生物反应器高密度培养的二个关键问题。 本文以蜈蚣藻、多管藻、孔石莼3种海藻的丝状体无性系为起始材料,分别构建了绒球状、网状和簇生这3类微球体,通过研究其形态建成的原理和方法,提出构建各类海藻的微球体的普适性原理和技术。 采用自制的光合测定装置、光温双梯度培养装置和藻类生物反应器等研究了微球体的光合特性、培养条件、营养盐吸收,建立了相关的研究方法。 以比较典型的孔石莼簇生状微球体为代表,进行了微球体光能利用情况的研究,着重分析研究了长期以来一直被忽视的微球体内部的光衰减情况,建立了光衰减模型;将反应器表面至藻体表面和藻体内部的光能利用情况相结合,全面了解反应器培养中的光能传输问题。研究结果为改进光生物反应器和培养技术,提高光能利用效率,实现高密度培养提供了依据。 同时,这些海藻在细胞工程育苗、生态工程和天然产物生产等方面有着重要的应用价值,分别对其育苗、无机氮磷吸收、藻胆蛋白含量等方面进行了初步研究,为大型海藻的生物反应器培养应用于海藻良种化育苗养殖、药物等高值化产品生产和水产养殖水处理等开辟了新途径。
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卡拉麦里山有蹄类自然保护区是世界著名的荒漠有蹄类自然保护区, 区内有蒙古野驴(E. hemionus)、鹅喉羚(G. subgutturosa)、盘羊(Ovis ammon)以及近期野放的普氏野马(E. przewalski)。经过多年有效保护和管理,区内蒙古野驴及鹅喉羚种群得到恢复并有较大增长。从2006年开始,我们在该保护区开展了蒙古野驴和鹅喉羚的食性构成、社群结构、种群密度、卧息及采食生境利用、季节性栖息地利用等方面的研究。主要结果如下: 采用粪样显微分析技术研究了蒙古野驴、鹅喉羚与家羊、家马和家骆驼3种家养动物春季、秋季和冬季食性组成及食物生态位。结果发现:(1) 该区域的蒙古野驴、鹅喉羚和家畜所采食的植物科数和种数都不相同,针茅、驼绒藜、蒿和梭梭在各自食谱中所占的比例不同, 但蒙古野驴、鹅喉羚和家畜主要采食针茅、驼绒藜、蒿和梭梭;(2) 春季、秋季和冬季这些野生与家养草食动物两两之间的食物生态位重叠均在0.8以上,最低为0.832(冬季:鹅喉羚和家马),最高达到0.986(秋季:蒙古野驴和家羊;秋季:家马和家羊)。五种有蹄类之间的食物生态位重叠度也达到了0.3以上。表明在卡拉麦里山有蹄类自然保护区,上述野生动物及季节性进入该自然保护区的家畜之间均存在食物竞争。冬季积雪深,食物短缺, 荒漠有蹄类易因冻饿及疾病等造成死亡。因此,应采取限制秋冬季进入该自然保护区家畜数量及调整放牧区域等保护管理措施,对该区域荒漠有蹄类实施有效保护。 对蒙古野驴和鹅喉羚的集群行为进行了初步研究。将鹅喉羚或蒙古野驴集群划分为雌性群、雄性群、母仔群、雌雄混群和独羚或独驴5种类型。共统计蒙古野驴556群次,计8235匹次。其中,雌雄混群223群次, 占40%, 为最多的集群类型;其余为雄性群(24%)、独驴(19%)、雌性群(11%)和母仔群(6% )。不同集群大小的比例差异极显著 (P=0.000)。其中2-30匹的集群占69%,独驴占18%,其余为13%。最大集群为266匹。除独驴外,其余4种集群类型的集群大小存在极显著差异。独驴作为一种特殊的集群类型,其占雄性个体的比例达63%,说明雄性个体比雌性更容易形成独驴。观察记录到鹅喉羚1286群次,计9148只次。其中,雌雄混群459群次, 占35%,为最多的集群类型;其余为独羚(18%)、母仔群(18%)、雄性群(17%)和雌性群(12%)。不同大小集群的比例差异极显著(P=0.000),其中2一15头的集群占73%, 16头以上集群占42%,独羚仅占3%,不同集群大小差异也极为显著(P=0.000)。除独羚外,其余4种集群类型的集群大小存在极显著差异。独羚作为一种特殊的集群类型,其雌性个体的比例占到55%,因此, 不能说明雄性比雌性更容易形成独羚。 分四个季节采用截线取样法,用DISTANCE5.0估计了蒙古野驴、鹅喉羚的密度和遇见率。根据DISTANCE5.0计算,该区域春季蒙古野驴种群密度为0.55±0.14匹/km2 (平均数±标准差,下同),夏季为0.60±0.13匹/km2,秋季为0.78±0.19匹/km2和冬季为0.54±0.14匹/km2。春季、夏季、秋季和冬季的鹅喉羚种群密度分别为1.14± 0.18头/km2,0.95±0.12头/km2,1.08±0.18头/km2和1.54±0.31头/km2。将这些结果与本区域不同时期及不同地域的蒙古野驴、鹅喉羚密度和遇见率数据进行了比较对比。截线取样法为研究干旱地区的有蹄类动物提供了一种标准方法,本研究结果为卡拉麦里自然保护区蒙古野驴和鹅喉羚的长期监测提供了基础数据。 采用样方法研究了鹅喉羚夏季和冬季卧息生境选择。夏季测定了49个卧迹样方,36个对照样方;冬季测定了75个卧迹样方,75个对照样方。研究发现,春季鹅喉羚主要选择平滩、下坡位和无坡位、海拔高度910米以上、与水源距离较远、远离道路、远离居民点、隐蔽级高、中低植被密度和中高草本密度的区域作为卧息生境;而冬季则主要选择山坡、阳坡和半阴半阳坡、中上坡位和下坡位、海拔900~1000m范围、离道路501~1000m以及大于2000m的距离、靠近居民点、中低隐蔽级、中厚度(1.1-3cm)雪深、中高植被密度和中高草本密度的区域作为卧息生境。主成分分析表明,卡拉麦里山鹅喉羚夏季季卧息样方前4个主成分的累积贡献率达到86.57%,第1主成分主要反映卧迹样方的植物密度、草本密度、针茅密度、至最近居民点距离、至永久水源最近距离和海拔。冬季该区域鹅喉羚卧息样方前4个主成分的累积贡献率达到73.88%,第1主成分主要反映卧迹样方的植物密度、草本密度、针茅密度和坡度。 通过设立样方研究了蒙古野驴的采食生境。研究发现,夏季和秋季两个季节蒙古野驴主要在平滩和山沟采食。集中在无坡向的平滩、1001m以上的海拔高度、与水源距离较近、远离道路、远离矿区等人类活动点、植被盖度高、草本盖度高、植物多样性高、草本多样性高(P<0.05)的区域采食。主成分分析表明,夏季影响蒙古野驴采食生境选择的环境因子是植物盖度、草本盖度、针茅盖度、植物密度、草本密度、针茅密度、植物种类、草本种类和禾本科种类。秋季影响蒙古野驴采食生境选择的环境因子是海拔、植物盖度、草本盖度、针茅盖度、植物密度、草本密度、针茅密度、植物种类、草本种类和禾本科种类。 利用卡山保护区不同季节野外种群调查数据,以3S技术为手段,评价了蒙古野驴和鹅喉羚季节性栖息地适宜性。首先把各季节蒙古野驴和鹅喉羚分布点图层,分别和固定水源点图层、道路图层、固定冬牧点图层和矿点图层进行叠加和距离查询,用Vanderploeg & Scavia’s选择指数(Ei*)分析了蒙古野驴和鹅喉羚季节性栖息地选择及其主要影响因素,建立了固定水源点、植被、道路、固定冬牧点和矿点对蒙古野驴和鹅喉羚栖息地影响强度的评价标准。通过缓冲区分析,分别研究了固定水源点、道路、固定冬牧点、矿点对蒙古野驴和鹅喉羚季节性栖息地的影响。通过缓冲区分析,综合研究了与人类活动有关的道路、固定冬牧点和矿点因子对蒙古野驴和鹅喉羚季节性栖息地的影响。最后将固定水源点、植被、道路、固定冬牧点和矿点等5个因子结合起来通过地图综合查询研究分析了这些因子对蒙古野驴和鹅喉羚季节性栖息地的综合影响,在固定水源点较适宜以上范围给出了该保护区蒙古野驴和鹅喉羚季节性不同适宜等级的生境面积。 我们建议采取以下积极措施来保护卡山保护区荒漠生态系统多样性以有效保护该区域内栖息的蒙古野驴和鹅喉羚:提高保护区周边社区政府的认识,提高公众参与自然资源和生物多样性保护的意识;加强水源地建设,积极采取飞播等措施,恢复植被,提高栖息生境质量;逐步限制进入卡拉麦里山越冬渡春的家畜数量;严格进入卡山保护区采矿制度,取缔非法矿业;加强草原围栏生态通道建设;与蒙古国合作建立跨国界的国际自然保护区;建立卡山自然保护区自然资源有偿使用机制;开展长期蒙古野驴和鹅喉羚种群监测。
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深入探讨了以知识为基础的产品的概念,从而为各行各业的发展指出了广阔的前景。
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Acoustic Gravity waves (AGW) play an important role in balancing the atmospheric energy and momentum budget. Propagation of gravity wave in the atmosphere is one of the important factors of changing middle and upper atmosphere and ionosphere. The purpose of this dissertation is to study the propagation of gravity wave in a compression atmosphere whit means of numerical simulation and to analyze the response of middle and upper atmosphere to pulse disturbance from lower atmosphere. This work begins with the establishment of 2-D fully nonlinear compressible atmospheric dynamic model in polar coordinate, which is used ton numerically study gravity wave propagation. Then the propagation characteristics of acoustic gravity wave packets are investigated and discussed. We also simulate the response of middle and upper atmosphere to pulse disturbance of lower atmosphere in background winds or without background winds by using this model and analyze the data we obtained by using Fourier Transform (FT), Short-time Fourier Transform (STFT) and Empirical Mode Decomposition (EMD) method which is an important part of Hilbert-Huang Transform (HHT). The research content is summarized in the following: 1. By using a two-dimensional full-implicit-continuous-Eulerian (FICE) scheme and taking the atmospheric basic motion equations as the governing equations, a numerical model for nonlinear propagation of acoustic gravity wave disturbance in two-dimensional polar coordinates is solved. 2. Then the propagation characteristics of acoustic gravity wave packets are investigated and discussed. Results of numerical simulation show that the acoustic gravity wave packets propagate steadily upward and keep its shape well after several periods. 3. We simulate the response of middle and upper atmosphere to pulse disturbance of lower atmosphere in background winds or without background winds by using this model, and obtain the distribution of a certain physical quantity in time and space from earth’s surface to 300km above. The results reveal that the response of ionosphere occurs at a large horizontal distance from the source and the disturbance becomes greater with increasing of height. The situation when the direction of the background wind is opposite to or the same as the direction of disturbed velocity of gravity-wave is studied. The results show that gravity wave propagating against winds is easier than those propagating along winds and the background wind can accelerate gravity wave propagation. Just upon the source, an acoustic wave component with period of 6 min can be found. These images of simulation are similar to observations of the total electron content (TEC) disturbances caused by the great Sumatra-Andaman earthquake on December 26 in 2004. 4. Using the EMD method the disturbed velocity data of a certain physical quantity in time and space can be decomposed into a series of intrinsic mode function (IMF) and a trend mode respectively. The results of EMD reveal impact of the gravity wave frequency under the background winds.
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在扬子地台贵州台江八郎下、中寒武统界线剖面界线附近,碳酸盐岩和干酪根碳同位素组成有规律变化。δ13Cker (PDB) 值在23314 ‰和226. 5 ‰间漂移与δ13Ccarb (PDB) 值在2217 ‰和+ 311 ‰间变化,反映了当时海水的碳同位素组成。无机和有机碳同位素组成之差的Δδ值,沿剖面不断变小,指示剖面上部样品可能受到热扰动和成岩后期作用影响。碳同位素规律的变化,反映了最初的沉积信息,特别是有机质埋藏量的变化,这些变化与早2中寒武世环境变化和生物组合差异有关。
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The MOS transistor physical model as described in [3] is presented here as a network model. The goal is to obtain an accurate model, suitable for simulation, free from certain problems reported in the literature [13], and conceptually as simple as possible. To achieve this goal the original model had to be extended and modified. The paper presents the derivation of the network model from physical equations, including the corrections which are required for simulation and which compensate for simplifications introduced in the original physical model. Our intrinsic MOS model consists of three nonlinear voltage-controlled capacitors and a dependent current source. The charges of the capacitors and the current of the current source are functions of the voltages $V_{gs}$, $V_{bs}$, and $V_{ds}$. The complete model consists of the intrinsic model plus the parasitics. The apparent simplicity of the model is a result of hiding information in the characteristics of the nonlinear components. The resulted network model has been checked by simulation and analysis. It is shown that the network model is suitable for simulation: It is defined for any value of the voltages; the functions involved are continuous and satisfy Lipschitz conditions with no jumps at region boundaries; Derivatives have been computed symbolically and are available for use by the Newton-Raphson method. The model"s functions can be measured from the terminals. It is also shown that small channel effects can be included in the model. Higher frequency effects can be modeled by using a network consisting of several sections of the basic lumped model. Future plans include a detailed comparison of the network model with models such as SPICE level 3 and a comparison of the multi- section higher frequency model with experiments.
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This thesis investigates the problem of estimating the three-dimensional structure of a scene from a sequence of images. Structure information is recovered from images continuously using shading, motion or other visual mechanisms. A Kalman filter represents structure in a dense depth map. With each new image, the filter first updates the current depth map by a minimum variance estimate that best fits the new image data and the previous estimate. Then the structure estimate is predicted for the next time step by a transformation that accounts for relative camera motion. Experimental evaluation shows the significant improvement in quality and computation time that can be achieved using this technique.
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Poolton, Nigel; Hamilton, B.; Evans, D.A., (2005) 'Synchrotron-laser pump-probe luminescence spectroscopy: Correlation of electronic defect states with x-ray absorption in wide-gap solids', Journal of Physics D: Applied Physics 38 pp.1478-1484 RAE2008
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F. Baria, M. Khalid, W. Haresign, A. Murray and B. Merrell (2003). Factors affecting the survival of sheep embryos after transfer within a MOET program. Theriogenology, 59 (5/6), 1265-1275. Sponsorship: DEFRA RAE2008
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13 hojas : 17 ilustraciones fotográficas.
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Two new notions of reduction for terms of the λ-calculus are introduced and the question of whether a λ-term is beta-strongly normalizing is reduced to the question of whether a λ-term is merely normalizing under one of the new notions of reduction. This leads to a new way to prove beta-strong normalization for typed λ-calculi. Instead of the usual semantic proof style based on Girard's "candidats de réductibilité'', termination can be proved using a decreasing metric over a well-founded ordering in a style more common in the field of term rewriting. This new proof method is applied to the simply-typed λ-calculus and the system of intersection types.