995 resultados para Printz, Johan, 1592-1663.
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采用产业经济学、计量经济学、统计学和GIS中的相关方法和技术,定量评价黄河中上游能源化工区产业结构演进的特征。刻画黄河中上游产业结构演进的总体特征,运用偏离—份额分析法分析三次产业及其内部结构演进的数量特征,利用产业相似系数等产业结构指标计算分析制造业内部结构的动态演进特征,并结合区位商和产业比重探究区域经济快速发展的内在机制。最后,归纳出黄河中上游能源化工区产业结构演进的主要驱动力是资源禀赋优势、市场需求拉动和政府政策引导,并针对性地提出"优化第二产业结构,保证第一产业发展,重点扶持第三产业"的对策。
Monolithic carbon aerogels from sol-gel polymerization of phenolic resoles and methylolated melamine
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Mononuclear Cu-I complexes with mixed ligands are used to fabricate green phosphorescent organic light-emitting diodes. The electroluminescence (EL) maximum at 524 nm coincides well with its photoluminescent (PL) spectrum in poly(methyl methacrylate) film (see Figure). A maximum current efficiency of 10.5 cd A(-1) at 105 cd m(-2) and a maximum brightness up to 1663 cd m(-2) are
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Nonisothermal crystallization and melting behavior of poly(3-hydroxybutyrate) (PHB) and maleated PHB were investigated by differential scanning calorimetry using various cooling rates. The results show that the crystallization behavior of maleated PHB from the melt greatly depends on cooling rates and its degree of grafting. With the increase in cooling rate, the crystallization process for PHB and maleated PHB begins at lower temperature. For maleated PHB, the introduction of maleic anhydride group hinders its crystallization, causing crystallization and nucleation rates to decrease, and crystallite size distribution becomes wider. The Avrami analysis, modified by Jeziorny, was used to describe the nonisothermal crystallization of PHB and maleated PHB. Double melting peaks for maleated PHB were observed, which was caused by recrystallization during the heating process.
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C12H12I2Te4, M(r) = 920.44, monoclinic, P2(1)/n, a = 10.942 (2), b = 14.924 (2), c = 11.415 (2) angstrom, beta = 104.32 (1)-degrees, V = 1806.0 (5) angstrom 3, Z = 4, D(x) = 3.38 g cm-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 100.7 cm-1, F(000) = 1592, T = 294 K, R = 0.033 for 1828 observed reflections. One of the Te atoms is bonded to the two I atoms, which are on either side of the molecular plane. The Te-I distances are 2.963 (1) and 2.961 (1) angstrom, which means oxidation at the Te atom instead of at the C = C bonds.
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Penicillium herquei isolate GA4 was isolated from the infected Conchocelis of Porphyra yezoensis. A large-scale fermentation using yeast extract sucrose medium and repeated chromatography afforded a new symmetrical urea derivative, hualyzin (1). The structure was determined by detailed NMR spectroscopic investigations and MS fragmentation analysis.
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机器人行走空间的复杂性决定了导航监控系统不仅为机器人提供行走路线,还要依据预先得到的先验数据与知识告诉机器人不同行走段的障碍分布、环境边界走向及约束程度,按照载体的几何形状,运动特性选择合适的速度、加速度,保证在安全的前提下最快完成行走.本文讨论了提取影响机器人当前行走的障碍、环境边界算法和不同行走速度段的划分与关键点抽取方法,讨论了各种速度段的分离、合并、高速行走段的插补和过短行走段的平滑滤除等等.
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Increasing attentions have been paid to the subsurface geological storage for CO2 in view of the huge storage capacity of subsurface reservoirs. The basic requirement for subsurface CO2 storage is that the CO2 should be sequestrated as supercritical fluids (physical trapping), which may also interact with ambient reservoir rocks and formation waters, forming new minerals (chemical trapping). In order to the effective, durable and safe storage for CO2, enough storage space and stable sealing caprock with strong sealing capacity are necessitated, in an appropriate geological framework. Up till now, hydrocarbon reservoirs are to the most valid and appropriate CO2 storage container, which is well proven as the favorable compartment with huge storage capacity and sealing condition. The thesis focuses on two principal issues related to the storage and sealing capacity of storage compartment for the Qingshankou and Yaojia formations in the Daqingzijing block, Southern Songliao Basin, which was selected as the pilot well site for CO2-EOR storage. In the operation area, three facies, including deltaic plain, deltaic front and subdeep-deep lake facies associations, are recognized, in which 11 subfacies such as subaqueous distributary channel, river- mouth bar, interdistributary bay, sheet sandbody, crevasse splay and overflooding plain are further identified. These subfacies are the basic genetic units in the reservoir and sealing rocks. These facies further comprise the retrogradational and progradational depositional cycles, which were formed base- level rise and fall, respectively. During the regressive or lake lowstand stage, various sands including some turbidites and fans occurred mostly at the bottom of the hinged slope. During the progradation stage, these sands became smaller in size and episodically stepped backwards upon the slope, with greatly expanded and deeped lake. However, most of Cretaceous strata in the study area, localized in the basin centre under this stage, are mainly composed of grey or grizzly siltstones and grey or dark grey mudstones intercalated with minor fine sandstones and purple mudstones. On the base of borehole and core data, these siltstones are widespread, thin from 10 to 50 m thick, good grain sorting, and have relative mature sedimentary structures with graded bedding and cross- lamination or crossbeds such as ripples, which reflect strong hydrodynamic causes. Due to late diagenesis, pores are not widespread in the reservoirs, especially the first member of Qingshankou formation. There are two types of pores: primary pore and secondary cores. The primary pores include intergranular pores and micropores, and the secondary pores include emposieus and fracture pores. Throat channels related to pores is also small and the radius of throat in the first, second and third member of Qingshankou formation is only 0.757 μm, 0.802 μm and 0.631 μm respectively. In addition, based on analyzing the probability plot according to frequency of occurrence of porosity and permeability, they appear single- peaked distribution, which reflects strong hetero- geneity. All these facts indicate that the conditions of physical property of reservoirs are not better. One reason may be provided to interpret this question is that physical property of reservoirs in the study area is strong controlled by the depositional microfacies. From the statistics, the average porosity and permeability of microfacies such as subaqueous distributary channel, channel mouth bar, turbidites, is more than 9 percent and 1md respectively. On the contrary, the average porosity and permeability of microfacies including sand sheet, flagstone and crevasse splay are less than 9 percent and 0.2md respectively. Basically, different hydrodynamic environment under different microfacies can decide different physical property. According to the reservoir models of the first member of Qingshankou formation in the No. well Hei47 block, the character of sedimentary according to the facies models is accord to regional disposition evolution. Meantime, the parameter models of physical property of reservoir indicate that low porosity and low permeability reservoirs widespread widely in the study area, but the sand reservoirs located in the channels are better than other places and they are the main sand reservoirs. The distribution and sealing ability of fault- fractures and caprock are the key aspects to evaluate the stable conditions of compartments to store CO2 in the study area. Based on the core observation, the fractures widespread in the study area, especially around the wells, and most of them are located in the first and second member of Qingshankou formation, almost very few in the third member of Qingshankou formation and Yaojia formation instead. In addition, analyzing the sealing ability of eleven faults in the three-dimensional area in the study area demonstrates that most of faults have strong sealing ability, especially in the No. well Hei56 and Qing90-27. To some extent, the sealing ability of faults in the No. well Hei49, Qing4-6 and Qing84-29 are worse than others. Besides, the deposition environment of most of formations in the study area belongs to moderately deep and deep lake facies, which undoubtedly take advantage to caprocks composed of mudstones widespread and large scale under this deposition environment. In the study area, these mudstones distribute widely in the third member of Qingshankou formation, Yaojia and Nenjiang formation. The effective thickness of mudstone is nearly ~550m on an average with few or simple faults and fractures. In addition, there are many reservoir beds with widely- developed insulated interbeds consist of mudstones or silty mudstone, which can be the valid barrier to CO2 upper movement or leakage through diffusion, dispersion and convection. Above all, the closed thick mud caprock with underdeveloped fractures and reservoir beds can be taken regard as the favorable caprocks to provide stable conditions to avoid CO2 leakage.
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从喀斯特石漠化的科学内涵出发,探讨喀斯特石漠化评价的具体内容,指出喀斯特石漠化评价应从现状、危险性以及发展速率3 个方面进行。评价指标选取所依据的原则,探讨了指标体系适用的时、空尺度范围;根据已有研究成果,分析喀斯特石漠化不同等级指标量化界线确定的生态基准,初步建立了石漠化评价的指标体系。
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This thesis investigates what knowledge is necessary to solve mechanics problems. A program NEWTON is described which understands and solves problems in mechanics mini-world of objects moving on surfaces. Facts and equations such as those given in mechanics text need to be represented. However, this is far from sufficient to solve problems. Human problem solvers rely on "common sense" and "qualitative" knowledge which the physics text tacitly assumes to be present. A mechanics problem solver must embody such knowledge. Quantitative knowledge given by equations and more qualitative common sense knowledge are the major research points exposited in this thesis. The major issue in solving problems is planning. Planning involves tentatively outlining a possible path to the solution without actually solving the problem. Such a plan needs to be constructed and debugged in the process of solving the problem. Envisionment, or qualitative simulation of the event, plays a central role in this planning process.
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This thesis presents a theory of human-like reasoning in the general domain of designed physical systems, and in particular, electronic circuits. One aspect of the theory, causal analysis, describes how the behavior of individual components can be combined to explain the behavior of composite systems. Another aspect of the theory, teleological analysis, describes how the notion that the system has a purpose can be used to aid this causal analysis. The theory is implemented as a computer program, which, given a circuit topology, can construct by qualitative causal analysis a mechanism graph describing the functional topology of the system. This functional topology is then parsed by a grammar for common circuit functions. Ambiguities are introduced into the analysis by the approximate qualitative nature of the analysis. For example, there are often several possible mechanisms which might describe the circuit's function. These are disambiguated by teleological analysis. The requirement that each component be assigned an appropriate purpose in the functional topology imposes a severe constraint which eliminates all the ambiguities. Since both analyses are based on heuristics, the chosen mechanism is a rationalization of how the circuit functions, and does not guarantee that the circuit actually does function. This type of coarse understanding of circuits is useful for analysis, design and troubleshooting.
Resumo:
Sk?t, L., Humphreys, M. O., Armstead, I. P., Heywood, S., Sk?t, K. P., Sanderson, R., Thomas, I. D., Chorlton, K. H., & Sackville Hamilton, N. R. (2005). An association mapping approach to identify flowering time genes in natural populations of Lolium perenne (L.). Molecular Breeding, 15(3), 233-245. Sponsorship: BBSRC RAE2008