4 resultados para coerência textual

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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中国古代涉及植物学的文献可谓浩如烟海。由于中国植物种类繁多,加之方言的分化和文字的演变,古籍文献中的植物名称难以计数。距古愈久,失误愈多,渐至名称混乱难以分辨,同物异名、同名异物现象比比皆是。植物考据在这样的背景下产生了。本文确立了中国植物考据研究的范围、内容、证据、方法和目的,并以时间为线索,梳理了中国植物考据研究两千多年的历史,扼要评介了各个历史阶段的代表人物及作品。在此基础上,本文遵循“由近及远,先实后虚”的研究思路,考证了《植物名实图考》的几种百合科植物,同时选定茄子这一栽培植物,以它为点,利用中国古籍文献证据,研究它在中国的起源、驯化和传播,藉此探讨植物考据研究所能解决的植物学问题。 1. 粉条儿菜和肺筋草考 理清了近百年来“粉条儿菜”和“肺筋草”这两个植物中文名称的混乱,确认粉条儿菜一名最早见于《救荒本草》,实为菊科Compositae鸦葱属Scorzonera华北鸦葱Scorzonera albicaulis;首次记载于《植物名实图考》中的“肺筋草”才是Aletris 属植物,应为Aletris scopulorum,非前人考证的Aletris spicata。 2. 黄精属植物考 《图考》“黄精”包括了多花黄精Polygonatum cyrtonema、长梗黄精P. filipes和距药黄精P. franchetii,这三个种实际上是一个集合种 (species aggregate), 即使用现代分类的观点来看,它们之间也很难从外部形态区分开来;“黄精苗”可能为P. sibiricum或P. verticillatum;认为“滇钩吻(一)”应为点花黄精P. punctatum,这与前人的考证结果相同;“滇钩吻(二)”和“滇黄精”可能分别为卷叶黄精P. cirrhifolium和滇黄精P. kingianum中的某个种,但限于黄精属植物分类研究的程度,暂且存疑;“萎蕤”图所绘植物不属于黄精属Polygonatum,而为万寿竹属Disporum的横脉万寿竹D.trabeculatum。 3. 贝母考 《图考》贝母条下所附贝母图,不属于贝母属Fritillaria植物,而属天南星科Araceae,可能为半夏Pinellia ternata的幼苗;文中“点苍山生者”可能是鸭趾草科蓝耳草Cyanotis vaga;“张子诗”中的蔓生贝母为Bolbostemma paniculatum,这可能是中国古代最早利用的“贝母”,后来逐渐被Fritillaria属植物替代。 4. 茄子的栽培起源和传播 本文首先借助于现代系统学和遗传学的研究结果,理清茄子及其近缘种的分类、地理分布和可能的驯化过程;结合民族植物学研究和大量的野外考察,确认了茄子及其近缘种在中国的形态、分布和利用方法等等;而后将今论古,用严格的考据方法理清在浩如烟海的中国古籍文献中与茄子相关文献的科学含义。在这个基础上推演茄子在中国栽培起源和传播的途径。得到以下结论:茄子的野生种GroupF和原始栽培种Group G在中国南方热带地区存在,早在晋代记载的“茄树”很可能就是这个原始栽培种Group G;高级栽培种Group H最早在公元前一世纪就有记载,有可能在中国四川盆地南部山区的暖温带地区被首先驯化;中国有些茄子的高级栽培种Group H也有可能从印度传来,但传播路线应该是沿着由南向北的西南丝绸之路,而非如一些学者所认为的自西向东由西北丝绸之路首先传入长安;在中国,茄子的高级栽培种由成都平原向长江中下游地区传播,继而在公元五到六世纪传播到黄河中下游地区,栽培技术已经成熟,利用方法越来越多, 到了宋代已经遍布整个中国;茄子在中国的选育是向着果实体积变大、味道变甜的方向进行, 宋代茄子发生了明显的品种分化,出现了世界上最早的茄子图。

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Two types of SiO2 with different mesopore size and HZSM-5 zeolite were used to prepare hybrid supported cobalt-based catalysts. The textual and structural properties of the catalysts were studied using N-2 physisorption, X-ray diffraction (XRD), and H-2 temperature-programmed reduction (TPR) techniques. Fischer-Tropsch synthesis (FTS) performances of the catalysts were carried out in a fixed-bed reactor. The combination effects of the meso- and micropores of the supports as well as the interaction between supports and cobalt particles on FTS activity are discussed. The results indicate that the catalyst supported on the tailor-made SiO2 and HZSM-5 hybrid maintained both meso- and micropore pores during the preparation process without HZSM-5 particles agglomerating. The mesopores provided quick mass transfer channels, while the micropores contributed to high metal dispersion and accelerated hydrocracking/hydroisomerization reaction rate. High CO conversion of 83.9% and selectivity to gasoline-range hydrocarbons (C-5-C-12) of 55%, including more than 10% isoparaffins, were achieved simultaneously on this type of catalyst.

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Univ SE Calif, Ctr Syst & Software Engn, ABB, Microsoft Res, IEEE, ACMSIGSOFT, N Carolina State Univ Comp Sci

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The historical land use and land cover changes is one of the key issues in LUCC research. However, the achievement of China in this field doesn't match her position in the world yet. And the reliability of the quantitive records in Chinese historical literature, the basic data for historical land use research, has been doubted. This research focuses on Re-Cha-Sui, a typical area for the farming-pastoral region in the north of China, to make a detailed case study in this field. Based on a deep mining and calibration on the data from massive historical documents and land-use surveys, the author gives a detailed analysis on the administrative region evolution, historical population dynamics, reclamation policy, and the land statistic system. According to textual researches, parallel validation and physical geographical analysis, a unified land use series for recent 300 years, which founded on the results of modern land-use surveys, is constructed. And the thematic maps on the cultivation index for different counties in several temporal sections are plotted. Based on the endeavor above, the dynamic of forest and steppe is reconstructed as well. The temporal-spatial patterns of land use/land cover changes in the area is analyzed. And the influence of different driving forces are discussed. The main conclusions of the research are as followed: 1. The quantitive records in literatures on Re-Cha-Sui area are reflection of real amounts of croplands. It is practical to reconstruct a result comparable with the modern land-use surveys, based of a deep mining and considerate validation on historical documents. The unexceptional negative attitude towards the numerical records in historical documents is unnecessary. 2. In recent 300 years, 3 climax of reclamation appeared in Re-Cha-Sui area and altered the pure pastoral area into a farming-pastoral region. The interval were respectively the early time till mid time of the Qing dynasty, the end of the Qing dynasty till early time of the Republic of China(ROC), and the time after A.D. 1949. After the first expansion, the area of cropland in this region reached 2.0 million ha. Among them, Guisui area, which was most densely cultivated, had a cultivation index over 30%, which is similar with modern situation. The second expansion covered broader area, and the amount of cropland reached 3.5 million ha. The increase of farming area after 1949 is due to the recultivation of abandoned farmland. The current area of cropland in this region is 5.6 million ha. In the southern area where the land was reclaimed early, the amount on of the cropland has some fluctuation in 300 years. While in the new reclaimed area in the north, the area of cropland has kept the trend of increasing. 3. Due to the different natural conditions, most forests in Re-Cha-Sui area distribute in the mountain area of North Hebei province, and the upland of West Liaoning province, especially the former, which has a forest coverage near 70%. However, most of these forests were destroyed before the end of the Qing dynasty. In 1949, the natural forest near Chengde was nearly cleared up. They were partly renewed after 1949 due to plantation. 4. In the steppe zone such as northern Rehe, Suiyuan and Chahar, the area of steppe has a negative correlation with that of cropland. With the expansion of cropland, the percentage of steppe has shrunk from over 80% to 53%. In the mountain area of North Hebei province, steppe expanded with the shrinkage of forest, though cropland was expanding. The percentage once reached 60%, and then fell with the renew of forest. However, in the upland of West Liaoning province, the steppe shrink slowly from original 50% to current 26%, with the expansion of cropland. 5. The land use and land cover change in Re-Cha-Sui area in recent 300 years is driven by various factors, including human dimensions such as population, policy of the government, disorder of the society, cultural tradition, and natural factors such as climate change and natural disasters. Among them, pressure from surplus population is the basic driving force.