淀粉接枝丙烯酸制备高分子灭火剂

以淀粉／丙烯酸为原料，用二乙烯苯为交联剂，过硫酸钾和亚硫酸氢钠为引发体系．经接枝共聚制备淀粉／丙烯酸高吸水性树脂，再由高吸水性树脂制取高分子灭火剂．本文分析了交联剂用量、引发体系配比、单体中和度以及淀粉与单体配比等因素对吸水率的影响，并考察了高分子灭火剂的灭火性能．实验证明高吸水性树脂可吸蒸馏水600g／g，用它配制的高分子灭火剂是自来水灭火效能的14倍．     

耐盐性高吸水性树脂的合成工艺

采用水溶液法对合成耐盐性高吸水性树脂(SAP)的工艺条件进行了研究。得到最佳反应条件：聚合温度为50—60℃，聚合时间为3h，引发剂[(NH4)2S2O8]与淀粉的质量比为0．4％—0．6％，单体与淀粉的质量比为6—8，丙烯酰胺(AM)与丙烯酸(AA)的质量比为0．3—0．4．制得SAP的吸水率为400—700g/g，对0．9％ NaCl溶液的吸液率为100—130g/g，产品的吸水性和吸盐性均有明显提高。     

CDD改性淀粉高吸水树脂的研究

简述了高吸水树脂的发展史、研究概况及其前景。采用接枝共聚的实验方法，对玉米淀粉与甲基丙烯酸接技共聚制高吸水性树脂进行了吸水和吸盐方面性能研究。采用正交设计的方法得到了最适宜的工艺条件：在氢氧化钠的质量分数为20％～23％，过硫酸铵为淀粉的1．5％-3．0％和交联剂N，N-亚甲基双丙烯酰胺为淀粉的0．70％-0．85％的条件下，制备出了吸水倍率在97～260倍的高吸水性树脂。实验结果表明．该树脂具有良好的吸水性。     

丙烯酸制备高吸水性树脂及其性能研究

本文介绍了新型化工材料高吸水性树脂脂近几十年来国内外的发展状况,并以丙烯酸采用反相悬浮合成聚丙烯酸高吸水性树脂为例,研究了反应单体浓度、丙烯酸中和度、溶剂及反应温度对高吸水性树脂的吸水性能的影响。     

马铃薯淀粉高吸水性树脂的合成及性能研究

为优化马铃薯淀粉高吸水性树脂的合成工艺,采用水溶液聚合法进行接枝共聚制备高吸水性树脂,并对其性能进行研究.结果表明：当马铃薯淀粉与单体（g/mL）比例为1：7,丙烯酸与丙烯酰胺摩尔比为0.5：1,丙烯酸中和度为70％,反应温度60℃,引发剂、交联剂用量分别为单体的0.25 wt％,0.6 wt％,交联时间为1.5h.此条件下合成的高吸水性树脂吸蒸馏水倍率达到786 g/g,吸0.9％ NaCl倍率达到76.1g/g,且吸水速率较快.对人工血、人工尿及一价阳离子溶液有较好的吸收率;热稳定性较好,保水能力强,在室温条件下保水能力在7d左右;在30、40、50、60℃条件下保水能力均优于科翰98保水剂,但耐酸性较差,在中性偏碱的条件下具有很好的吸水倍率.     

硅藻土-聚丙烯酰胺系高吸水性复合材料的研制

以丙烯酸和硅藻土为原料，用溶液法合成复合高吸水性树脂，同时对影响聚合产物吸水量的各种因素进行了研究．结果表明，当硅藻土、淀粉、NaOH、引发剂和交联剂的加入量的质量分数分别为30％、30％、60％、1．5％及0．03％时，制得的超吸水性复合材料的吸水量最高，可达611g/g．硅藻土作为一种功能填料，改善了复合材料的综合吸水性能．     

淀粉接枝丙烯酸制备高分子灭火剂

.以淀粉/丙烯酸为原料,用二乙烯苯为交联剂,过硫酸钾和亚硫酸氢钠为引发体系.经接枝共聚制备淀粉/丙烯酸高吸水性树脂,再由高吸水性树脂制取高分子灭火剂.本文分析了交联剂用量、引发体系配比、单体中和度以及淀粉与单体配比等因素对吸水率的影响,并考察了高分子灭火剂的灭火性能.实验证明高吸水性树脂可吸蒸馏水600g/g,用它配制的高分子灭火剂是自来水灭火效能的14倍.     

耐电解质高吸水性树脂的合成和性能

以环已烷为连续相，丙烯酸作为单体，Span—60为悬浮稳定剂，过硫酸钾为引发剂，N，N’—亚甲基双丙烯酰胺为交联剂，加入不同量的丙烯酸聚氧乙烯酯作为改性剂，利用反相悬浮聚合方法制备耐电解质高吸水性树脂。发现一定比例丙烯酸聚氧乙烯酯的加入，可以明显改善高吸水性树脂的吸水能力和耐盐能力。     

丙烯酸-丙烯酸钠共聚合成高吸水性树脂的研究

采用反相悬浮聚合法合成丙烯酸丙烯酸钠高吸水性树脂。研究了反应单体浓度、丙烯酸中和度、交联剂、引发剂及反应温度对反相悬浮聚合产物性能的影响,为选择最佳配方和工艺条件提供了依据。     

聚六亚甲基胍盐酸盐的合成及其在纯棉织物上的应用

本文采用自由基溶液聚合的方法,合成了交联型聚丙烯酸钠阴离子高吸水性树脂,研究了引发剂用量,交联剂用量,丙烯酸中和度,单体浓度及反应温度等因素对树脂吸水性的影响,得到了最佳合成工艺条件。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the