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31.
人们对《盐铁论》的研究,大多集中在西汉政府盐铁官营专卖的经济思想和经济政策、桑弘羊与贤良文学们的“义利之辩”、汉武帝的内外政策之争、王道与霸道之论、以及对历史人物的品评等方面。实际上,《盐铁论》可以称得上是西汉中期的一部有关社会生活的百科全书,反映出西汉中期人们日常社会生活的全景。我们从《盐铁论》一书中既可以看到西汉中期人们衣、食、住、行、用、玩等各种日常生活物品,也可以看到西汉中期人们的日常社会生活状况和社会风气:物质文明的高度发展;社会生活的奢侈腐化;社会风气的江河日下;贫富两极的严重分化。  相似文献   
32.
基于GIS的黄淮海平原土壤盐分分布与管理研究   总被引:15,自引:0,他引:15  
本文通过GIS定位取样分析、Kriging插值和GIS处理,研究了黄淮海平原土壤盐分的空间分布,结果表明:黄淮海平原非盐渍土的面积为80.8%,轻度盐化土壤占17.0%,中度盐化占2.2%,重度盐化土壤的面积仅占0.04%。有7.2%的土壤表层(0∽10cm)虽无盐化现象,但20cm以下次土壤含盐量超0.1%;黄淮海平原盐渍化目前已主要分布于沿渤海湾低平原、河北省的衡水以北和山东南四湖地区,其它地区已无大面积盐渍土分布;从宏观而论,黄淮海平原的盐渍化程度正在减轻,土壤正向脱盐方向发展,大部分地区已经脱离了土壤盐渍化的困扰。但是,在上述三地区及周边地区,土壤盐渍化的治理与次生盐渍化的防治仍是近期农业管理所必须考虑的重要因素。  相似文献   
33.
张晓 《教育技术导刊》2010,9(5):192-193
目前根据三视图来完成三维图的绘制比较复杂。利用基于AutoCAD的软件-AdaucogitSalt,可以快速地实现三视图转换为三维立体图。Salt解决了工程师制图的繁琐过程,提高了工作效率,使设计者集中心力于创新。  相似文献   
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35.
商籍设立于明末,清承明制,并普及到全国各大盐场。明清商籍设立之初衷为方便远在他乡的盐商子弟参加科举应试,确保他们的科举权利。但因商籍设立与盐业资本之间的密切关系,商籍管理事实上赋予了盐商子弟一种科举特权。这样,商籍制度从设立伊始便具有二重属性:一为科举公平,一为政治交易。商籍管理的特权性质造成清代不断有人假冒商籍参加科举考试。为此,清政府逐步完善了商籍管理的各项制度,在一定程度上维护了科举考试的正常秩序。  相似文献   
36.
Roman cements, one of the most extensively produced types of hydraulic binders of the second half of the 19th century, played an important role in the architecture of many European countries. This paper deals with the chemical-mineralogical and microstructural characterisation of historic Roman cement renders from Budapest, Hungary. Different microscopic techniques were used on polished thin sections and fracture surfaces in order to understand the method of producing these renders and the effect of urban pollution on them. The renders exhibited characteristics typical to a Roman cement mortar, such as high binder to aggregate ratios (b/a), mostly fine-grained aggregates and high capillary porosity, but without the shrinkage cracks that are also normally present. This research suggests that coarse residual cement grains may have acted in a manner similar to aggregates by absorbing stress and thereby reducing the formation of shrinkage cracks. Based on the mineral characteristics of residual cement grains, the samples could be divided into two groups, which correspond to either a higher or lower temperature of calcination of the original source material of the cement. Chemical characteristics of the binders suggest the presence of intermixed CaCO3 originating from the carbonation of hydration products and partly from residual calcium carbonate of the raw material. Despite dense and often impermeable coats applied in later renovations and exposure to a polluted urban environment, which resulted in formation of gypsum on the surface of the renders, the samples show good to excellent state of preservation after more than a century. The strong “house of cards”-like arrangement of the complex C-(A)-S-H-type phases is responsible for both the high capillary porosity and the good resistance of Roman cement renders to atmospheric pollution and potentially damaging salts such as Na- and K-chlorides which are found near the base of the building due to sidewalk de-icing. These results help to better understand the behaviour of historic Roman cement renders, which in turn assists in making good decisions in choosing a repair material to future restorations of 19th century façades built with this material.  相似文献   
37.
The salt-gradient operation mode used in ion-exchange simulated moving bed chromatography (SMBC) can improve the efficiency of protein separations. A detailed model that takes into account any kind of adsorption/ion-exchange equilibrium, salt gradient, size exclusion, mass transfer resistance, and port periodic switching mechanism, was developed to simulate the complex dynamics. The model predictions were verified by the experimental data on upward and downward gradients for protein separations reported in the literature. All design and operating parameters (number, configuration, length and diameter of columns, particle size, switching period, flow rates of feed, raffinate, desorbent and extract, protein concentrations in feed, different salt concentrations in desorbent and feed) can be chosen correctly by numerical simulation. This model can facilitate the design, operation, optimization, control and scale-up of salt-gradient ion-exchange SMBC for protein separations.  相似文献   
38.
蚌埠地区设施土壤盐分累积特征研究   总被引:2,自引:0,他引:2  
对蚌埠市怀远和固镇两地不同年限设施土壤的盐分累积特征进行了研究,测定了土壤剖面各层次中的盐分总量和Na+、K+、NH4+、Ca2+、Mg2+、NO3-、H2PO4-、Cl-、SO42-、HCO3-等10种离子的含量,根据这10种离子之和与盐分总量的比值计算"盐分回收率".结果表明,大棚内土壤表层的盐分总量是露地土壤相同层次的2.4~5.7倍,盐分主要聚积在0~15cm土层中,尤其是0~5cm层次中;随着大棚使用年限的延长,盐分总量有增加趋势;除Na+和HCO3-外,NH4+、Ca2+、Mg2+、NO3-、H2PO4-、SO42-在大棚表层土壤中都有明显的累积,尤以Ca2+和NO3-累积严重,怀远大棚表层土壤的Ca2+和NO3-占盐分离子总量的63.8%,固镇大棚表层土壤的K+、Ca2+和NO3-占盐分离子总量的73.3%;根据"盐分回收率"推断,除了本文测定的10种离子外,还有相当数量(约占总盐的15%~23%)的其他重金属离子和非金属离子存在于大棚土壤中.  相似文献   
39.
桑弘羊理财活动的重要理论依据是管子的轻重学说。他运用管子轻重之学,推行盐铁官营、均输、平准和统一铸币权等重要经济政策,解决了汉武帝时期所面临的严重财政困难,为西汉王朝的强盛作出了杰出的贡献。了解轻重理论,将有助于我们了解桑弘羊的理财活动。  相似文献   
40.
Soybean (Glycine max (L.) Merrill) is a salt-sensitive crop, and its production is severely affected by saline soils. Therefore, the response of soybean seeds to salt stress during germination was investigated at both physiological and proteomic levels. The salt-tolerant cultivar Lee68 and salt-sensitive cultivar N2899 were exposed to 100 mmol/L NaCl until radicle protrusion from the seed coat. In both cultivars, the final germination percentage was not affected by salt, but the mean germination times of Lee68 and N2899 were delayed by 0.3 and 1.0 d, respectively, compared with controls. In response to salt stress, the abscisic acid content increased, and gibberellic acid (GA1+3) and isopentenyladenosine decreased. Indole-3-acetic acid increased in Lee68, but remained unchanged in N2899. The proteins extracted from germinated seeds were separated using two-dimensional gel electrophoresis (2-DE), followed by Coomassie brilliant blue G-250 staining. About 350 protein spots from 2-DE gels of pH range 3 to 10 and 650 spots from gels of pH range 4 to 7 were reproducibly resolved, of which 18 protein spots showed changes in abundance as a result of salt stress in both cultivars. After matrix-assisted laser desorption ionization-time of flight-mass spectroscopy (MALDI-TOF-MS) analysis of the differentially expressed proteins, the peptide mass fingerprint was searched against the soybean UniGene database and nine proteins were successfully identified. Ferritin and 20S proteasome subunit β-6 were up-regulated in both cultivars. Glyceraldehyde 3-phosphate dehydrogenase, glutathione S-transferase (GST) 9, GST 10, and seed maturation protein PM36 were down-regulated in Lee68 by salt, but still remained at a certain level. However, these proteins were present in lower levels in control N2899 and were up-regulated under salt stress. The results indicate that these proteins might have important roles in defense mechanisms against salt stress during soybean seed germination.  相似文献   
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