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241.
A proteinaceous binding media for the polychrome terracotta army of Emperor Qin Shihuang has been identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF-MS).Methods for the preparation of the model samples and the elimination of interferences have been evaluated,as well as ageing processes.A method involving the complexation of EDTA in combination with dialysis was used to eliminate any interference in the polychrome layers taken from the historical samples.The model samples were aged by being buried in loess to replicate the ageing process of the historical samples as closely as possible.The optimum conditions for the extraction and subsequent enzymatic hydrolysis of the extracted protein were investigated.Under the optimized conditions,the‘‘peptide mass fingerprints’’of the proteinaceous binding media from the historical and model samples were determined by MALDITOF-MS.The results revealed that animal glue was used as the binding media for the polychrome layers of Emperor Qin Shihuang’s terracotta army.It also shows that animal glue used as binding media has a long history in China.  相似文献   
242.
Strand electromagnetic stirring (S-EMS) and final electromagnetic stirring (F-EMS) are the main methods used to improve the center porosity and segregation for round blooms. To optimize the stirring conditions, nail shooting tests were conducted for three sections of large round blooms with diameters of ?380 mm, ?450 mm, and ?600 mm. Acid leaching and sulfur print tests were used to investigate the shell thickness. Based on the results of nail shooting tests, a mathematical model of solidification was established, and the variation of shell thickness and the central solid fraction were exactly calculated by the model. By taking all sections into account, the locations of S-EMS and F-EMS were optimized for each section. In the results, the macro-segregation of various sections is improved after the locations of S-EMS and F-EMS systems are changed.  相似文献   
243.
多个体参与交叉的遗传算法   总被引:2,自引:0,他引:2  
提出了多个体参与交叉的遗传算法,即采取新的交叉算子使子代个体同时含有多个父代个体的模式.突破了以前遗传算法只有两个个体参与交叉的局限,通过调整参与交叉的父代个体数目和交叉后产生的后代个体数目,实际上提出了遗传算法调试中的两个新参数.通过调整新参数,使得遗传算法可能有更高的计算效率.证明了多个体参与交叉的遗传算法的模式定理.将方差与熵作为描述遗传算法解群多样性的工具.分析了多个体参与交叉的遗传算法对解群方差及熵的影响.通过一个算例验证了多个体参与交叉的遗传算法具有较高的计算效率  相似文献   
244.
245.
山西省自然资源禀赋分析   总被引:1,自引:0,他引:1  
在分析山西省土地、水、气候、矿产等自然资源情况的基础上,阐述了各类资源的禀赋及生产、加工、转换过程中的特征,以期为资源的深度开发寻找适宜的技术与制度环境.  相似文献   
246.
中国海岸带耐盐经济植物资源   总被引:16,自引:2,他引:14  
我国海岸带耐盐经济植物种类十分丰富,约有115科359属517种具有经济潜力的耐盐植物,其中药用资源植物436种,芳香资源植物46种,纤维资源植物83种,油脂及树脂资源植物50种,饲草资源植物152种,此外还有蜜源植物和观赏植物。作者对其进行了分类评述,并在此基础上提出一些开发利用的建议。  相似文献   
247.
Gou  Kemian  Shang  Lijuan  An  Xiaorong  Deng  Jixian  Chen  Yongfu  Huang  Peitang 《科学通报(英文版)》1999,44(3):236-236
Western blot analysis revealed that one IgG1 monoclonal antibody (mAb) to sp18 family membrane proteins (Mr. 14, 16 and 18 ku) of bovine sperm reacted faintly with protein bands of 14, 18, 22, 30 and 60 ku (reducing) in samples of mouse sperm. The mAb also reacted to protein of egg lysozyme. Using a laser confocal microscope, indirect immunofluorescence (IIP) showed that the sp18 antigens were present in the posterior head of murine sperm. In murine in vitro fertilization (IVF) and embryo development trails, a total of 426 oocytes from C57BL/6 and F1 hybrid strain (CD1 × C57BL/6 cross) of 12 female mice were used in 3 independent trails. After preincubating capacitated sperm with 182 μg/mL of sp18 mAb in the modified TYH IVF medium for 15-20 min, cumulus-oocyte-complexes were introduced. The fertilization rate in sp18 mAb groups was 77.1 %, which was not significantly (P > 0.05) different from the nonspecific mouse IgG (79.2%) and non-IgG (80.3 %) control groups. Fertilized oocytes had been continuously cultured in modifed CZB medium. 100%, 100% and 97.9% of 1-cell embryos developed to 2-cell stage in sp18 mAb, nonspecific mouse IgG and non-IgG group 30 h after the start of fertilization, respectively. In the nonspecific mouse IgG and non-IgG groups, 64.1 % and 64.3% of embryos developed to the 4-cell stage, respectively, but all developing eggs in sp18 mAb groups arrested development in vitro at 2-cell stage. After zonae of 2-cell blocked embryos were enzy-matically removed with 0.5% pronase, detection of sp18 antigens by IIF indicated that the fluorescence scattered on two embryonic cells. For embryos fertilized in vivo and co-cultured with 182 μg/mL sp18 mAb, the numbers of 1-cell embryos reaching the 2-cell and 4-cell stage were 95. 2% and 70. 5%, which were not significantly (P>0.05) different from the control group (92.9% and 77.9%). These results indicate that the sp18 antigens on posterior head of mouse sperm were incorporated into the egg plasma membrane during fertilization, and played an active role in development of murine preimplanta-tion embryo.  相似文献   
248.
Using the isotopic diluting and thermal ionization mass spectrometric (TIMS) technique, the U-series dating procedure was established on the basis of measurement of national standard GBW04412. With this highly precise technique the Holocene corals from the South China Sea were dated. Comparison between this method and α-spectrometry was made. The results show that a thriving period of corals in the South China Sea appeared at 6 800-5 800 a BP, during which the paleosea level was the higher than at present in the Holocene.  相似文献   
249.
文章介绍了企业计算机信息集成系统的特点、组成及运行过程。通过与传统的MIS、CIMS的比较,指出该系统的特点:以信息集成为主线,从最终管理对象出发形成信息模型,组成稳定的数据结构,各种管理功能可从对数据结构中的数据处理而得到,注重人在整个信息集成过程中的主导作用。文中着重分析了系统模型的建立、信息的采集与集成及过程。  相似文献   
250.
材料疲劳损伤过程描述的智能方法   总被引:4,自引:1,他引:3  
对描述材料疲劳损伤过程的智能仿真方法进行了研究,建立了新的模型·它能定量地反映载荷顺序效应和材料疲劳特性,准确地描述材料疲劳损伤的复杂变化历程,材料的疲劳韧性视为常量,可作为失效判据·选用正火35钢进行了两级载荷及随机载荷疲劳试验,两种载荷作用下其寿命估算的最大误差分别为15-74%和8-9%·其寿命估算值与试验值吻合较好,分析精度较高·  相似文献   
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