双酶法制备低黏度辛烯基琥珀酸淀粉钠的工艺条件   总被引：4，自引：0，他引：4  

阳元娥  罗发兴  黄强  谭伟 《广东海洋大学学报》2004,24(4):49-53

对双酶法制备用作微胶囊壁材的低黏度辛烯基琥珀酸淀粉钠的工艺路线与工艺条件进行了研究。正交实验结果表明 ,在酯化淀粉乳质量浓度 2 0 %、每 g淀粉α 淀粉酶的用量为 6SKBU的条件下 ,影响产品性能的各因素中 ,糖化酶的用量对产品的DE值和流度的影响最大 ,各因素的重要性依次是 :糖化酶的用量、糖化酶作用时间、α 淀粉酶保温作用时间。最佳工艺条件是 :α 淀粉酶保温作用时间 4min ,每 g淀粉糖化酶用量 0 .2GAU ,糖化酶作用时间 2 .5h ,此时产品的DE值为 30 ,流度为 80左右  相似文献   

Size and shape evolution of pores in a viscoplastic matrix under compression     

M. Berli  M. L. Accorsi  D. Or 《国际地质力学数值与分析法杂志》2006,30(12):1259-1281

The frequent use of soils and earth materials for hydraulic capping and for geo‐environmental waste containment motivated our interest in detailed modelling of changes in size and shape of macro‐pores to establish links between soil mechanical behaviour and concurrent changes in hydraulic and transport properties. The objective of this study was to use finite element analysis (FEA) to test and extend previous analytical solutions proposed by the authors describing deformation of a single macro‐pore embedded in linear viscoplastic soil material subjected to anisotropic remote stress. The FEA enables to consider more complex pore geometries and provides a detailed picture of matrix yield behaviour to explain shortcomings of approximate analytical solutions. Finite element and analytical calculations agreed very well for linear viscous as well as for viscoplastic materials, only limited for the case of isotropic remote stress due to the simplifications of the analytical model related to patterns and onset of matrix‐yielding behaviour. FEA calculations were compared with experimental data obtained from a compaction experiment in which pore deformation within a uniform modelling clay sample was monitored using CAT scanning. FEA predictions based on independently measured material properties and initial pore geometry provided an excellent match with experimentally determined evolution of pore size and shape hence lending credence to the potential use of FEA for more complex pore geometries and eventually connect macro‐pore deformation with hydraulic properties. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

凤太矿田层控铅锌(铜)矿床的成矿物质来源探讨     

隗合明  吕仁生 《地球科学与环境学报》1990,(1)

秦岭凤太矿田层控铅锌(铜)矿床的金属物质、硫和成矿溶液主要来自深部基底的岩石,属海底喷流—沉积成因矿床。从这一理论认识出发可进一步分析控矿地质条件及今后在该区有效地寻找同类矿床。  相似文献   

Motive force of Qinghai-Tibet Plateau moving to east     

YANG Dong-hong  YANG Xue-xiang  CHEN Dian-you 《世界地质(英文版)》2005,8(1)

A calculation formula on spherical pattern of Qinghai-Tibet plateau moving model is established. Tibet massif moves norward by east in speed of 28 mm/a, Ganshu-Qinghai massif moves to northeast in speed of 15 mm/a, Qomolangma Feng moves northward by a few east in speed of 35 ～42 mm/a. The low latitude perimeter is longer than the nigh latitude perimeter. When the Tibet massif moves northward, its latitude perimeter must be contracted and the Tibet massif must move eastward by Coriolis. Coriolis force is inertial in earth rotation. It makes the fall body turning to east and the rising block turning westward. In the Northern Hemisphere, it makes the northward body turning to east and the southward block turning to west.This is the reason why the tectonic zones of western Pacific are different from those of eastern Pacific.  相似文献   

The importance of oxygen isotope provenance in relation to solute content of bulk meltwaters at Imersuaq Glacier,West Greenland     

Jacob C. Yde  N. Tvis Knudsen 《水文研究》2004,18(1):125-139

Stable oxygen isotope analysis and measurement of several dissolved cations and anions of bulk meltwater samples have provided information about the hydrochemical environment of the glacial hydrological system at Imersuaq Glacier, an outlet tongue from the Greenland ice‐sheet, West Greenland. The samples were collected at frequent intervals during the period 20–28 July 2000 in a small (<20 L s^?1) englacial meltwater outlet at the glacier margin. The results document the following findings: (i) a marked diurnal variation of δ¹⁸O is related to the composition of oxygen isotope provenances, mainly near‐marginal local superimposed ice and basal up‐sheared ice further up‐glacier; (ii) a relationship is seen between all base cations (Na⁺, K⁺, Ca²⁺, Mg²⁺), SO₄^2? and δ¹⁸O, indicating that solute acquisition is provided by solid–solution contact with the up‐sheared ice—as the relationship with Cl^? is weak the influence of seasalt‐derived solutes is small in the area; (iii) when the melt rate is high, two diurnal maxima of δ¹⁸O values and solute concentrations are measured, and it is suggested that a snow meltwater component is responsible for the second maximum of δ¹⁸O—a short residence time leads to a delayed decrease in ion concentrations. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

History of crustal growth and recycling at the Pacific convergent margin of South America at latitudes 29°–36° S revealed by a U–Pb and Lu–Hf isotope study of detrital zircon from late Paleozoic accretionary systems     

A.P. Willner  A. Gerdes  H.-J. Massonne 《Chemical Geology》2008,253(3-4):114-129

Detrital zircon provides a powerful archive of continental growth and recycling processes. We have tested this by a combined laser ablation ICP-MS U–Pb and Lu–Hf analysis of homogeneous growth domains in detrital zircon from late Paleozoic coastal accretionary systems in central Chile and the collisional Guarguaráz Complex in W Argentina. Because detritus from a large part of W Gondwana is present here, the data delineate the crustal evolution of southern South America at its Paleopacific margin, consistent with known data in the source regions.Zircon in the Guarguaráz Complex mainly displays an U–Pb age cluster at 0.93–1.46 Ga, similar to zircon in sediments of the adjacent allochthonous Cuyania Terrane. By contrast, zircon from the coastal accretionary systems shows a mixed provenance: Age clusters at 363–722 Ma are typical for zircon grown during the Braziliano, Pampean, Famatinian and post-Famatinian orogenic episodes east of Cuyania. An age spectrum at 1.00–1.39 Ga is interpreted as a mixture of zircon from Cuyania and several sources further east. Minor age clusters between 1.46 and 3.20 Ga suggest recycling of material from cratons within W Gondwana.The youngest age cluster (294–346 Ma) in the coastal accretionary prisms reflects a so far unknown local magmatic event, also represented by rhyolite and leucogranite pebbles. It sets time marks for the accretion history: Maximum depositional ages of most accreted metasediments are Middle to Upper Carboniferous. A change of the accretion mode occurred before 308 Ma, when also a concomitant retrowedge basin formed.Initial Hf-isotope compositions reveal at least three juvenile crust-forming periods in southern South America characterised by three major periods of juvenile magma production at 2.7–3.4 Ga, 1.9–2.3 Ga and 0.8–1.5 Ga. The ¹⁷⁶Hf/¹⁷⁷Hf of Mesoproterozoic zircon from the coastal accretionary systems is consistent with extensive crustal recycling and addition of some juvenile, mantle-derived magma, while that of zircon from the Guarguaráz Complex has a largely juvenile crustal signature. Zircon with Pampean, Famatinian and Braziliano ages (< 660 Ma) originated from recycled crust of variable age, which is, however, mainly Mesoproterozoic. By contrast, the Carboniferous magmatic event shows less variable and more radiogenic ¹⁷⁶Hf/¹⁷⁷Hf, pointing to a mean early Neoproterozoic crustal residence. This zircon is unlikely to have crystallized from melts of metasediments of the accretionary systems, but probably derived from a more juvenile crust in their backstop system.  相似文献   

Biaxial test simulations using a packing of polygonal particles   总被引：1，自引：0，他引：1  

A. A. Peña  A. Lizcano  F. Alonso‐Marroquin  H. J. Herrmann 《国际地质力学数值与分析法杂志》2008,32(2):143-160

The mechanical response of cohesionless granular materials under monotonic loading is studied by performing molecular dynamic simulations. The diversity of shapes of soil grains is modelled by using randomly generated convex polygons as granular particles. Results of the biaxial test obtained for dense and loose media show that samples achieve the same void ratio at large strains independent of their initial density state. This limit state resembles the so‐called critical state of soil mechanics, except for some stress fluctuations, which remain for large deformations. These fluctuations are studied at the micro‐mechanical level, by following the evolution of the co‐ordination number, force chains and the fraction of the sliding contacts of the sample. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

伊通盆地梁家地区奢岭组混源扇三角洲内幕结构   总被引：1，自引：0，他引：1  

石万忠  孔敏  宋志峰 《地球科学》2008,33(3):365-371

伊通盆地梁家地区(二号断层上盘)钻井揭示奢岭组是该区主要的油气富集层,目前研究结果认为奢岭组储集层是由两个方向的扇三角洲混合沉积形成,但由于资料有限,应用常规方法无法清楚地认识两个不同方向的物源混合沉积的扇三角洲的内幕特征以及这两个物源如何动态地控制着砂体的分布,影响了对该区油气储集层的深入认识.应用地震和地质资料,在波阻抗反演结果二次解释的基础,解析了这两个混合物源扇三角洲的内幕特征和演化特征,得出3个结论:(1)伊通盆地梁家地区奢岭组至少有4期扇三角洲沉积,每期扇三角洲的沉积范围由下向上逐渐扩大,反映了基准面逐渐下降的过程;(2)奢岭组的4期扇三角洲是由两个物源混合沉积形成,这4期扇三角洲逐渐由受从二号断层来的物源控制为主,变为由受从北东方向来的物源控制为主;(3)基于波阻抗体进行的砂层组解释和分析,能够清楚地分析扇三角洲沉积体的内幕结构,是应用波阻抗进行高分辨率地震分析和应用的一种新的分析方法.  相似文献   

空间刚架结构极限强度分析     

刘修禾 《海洋工程》1997,(3)

本文用理想结构单元法对空间刚架结构进行了极限强度分析，理想结构单元法在于将结构分成最大可能的单元。以简单的形式归并几何非线性与材料非线性。按增量形式加载，直到达到极限强度。本文根据Ｒａｓｈｅｄ理论导出了对称的切向方程组，节省了存贮单元、改善了破坏准则的描述。算例结果与非线性有限单元法结果十分吻合。  相似文献   

中太平洋铁锰结壳铅同位素研究   总被引：5，自引：0，他引：5  

周枫  凌洪飞  陆尊礼  蒋少涌 《海洋地质与第四纪地质》2005,25(1):55-62

已有研究表明大洋中溶解的铅(Pb)来源于陆源物质，但是，对Pb进入大洋的途径争议很大。为此分析了取自中太平洋两块铁锰结壳样品的Pb同位素组成，获得了整个新生代的中太平洋Pb同位素演化历史。结果表明这两块结壳的Pb同位素随时间的演化曲线与中北太平洋沉积物岩心LL44-GPC3中风成碎屑的Pb同位素演化曲线相似。证实该区深水中的天然溶解铅主要来自风成粉尘，并且50Ma之前中太平洋中溶解Pb同位素组成主要取决于源自美洲的风成粉尘的输入，40Ma之后主要取决于源自亚洲的风成粉尘的输入。  相似文献