α-Fe_2O_3纳米颗粒的制备及其对曙红B的吸附性能研究

以Fe(NO_3)_3·9H_2O与Na_2S_2O_3为前驱体溶液,加入表面活性剂聚乙烯吡咯烷酮(PVP),采用光化学合成方法首先制备FeO(OH)/S粉体材料,然后通过高温煅烧后得到Fe_2O_3纳米颗粒.结果表明,随着煅烧温度的升高,α-Fe_2O_3纳米颗粒的结晶度变好,晶粒粒度逐渐增大;α-Fe_2O_3纳米颗粒对曙红B具有较好的吸附效果,煅烧温度为400℃时吸附效果最佳.研究了不同吸附剂用量、p H对吸附性能的影响.Fe_2O_3纳米颗粒对曙红B的吸附过程符合二级动力学与Freundich等温吸附模型,最大吸附量为368 mg/g.     

毛竹遗态Fe_2O_3/Fe_3O_4/C复合材料对水中铬(Ⅵ)的吸附

以毛竹遗态Fe_2O_3/Fe_3O_4/C复合材料为吸附剂,研究铬(Ⅵ)不同的初始浓度、溶液初始pH不同、吸附剂不同的投加量、不同粒径的条件下对吸附效果的影响。结果表明:Cr(Ⅵ)溶液初始p H对吸附效果的影响最为显著,其次是吸附剂用量。温度、振荡时间、投加量等因素对Cr(Ⅵ)吸附作用影响不大。优化工艺的组合为:Cr(Ⅵ)浓度为10 mg/L,溶液初始pH=1,温度为45℃,吸附剂粒径小于100目,吸附剂用量为0.5 mg/50 mL,吸附时间为5 h。     

上转光剂掺杂钨酸铋复合物的制备及其光催化降解 罗丹明B的研究

采用溶胶-凝胶法制备了上转光剂Er~(3+):Y_3Al_5O_(12),然后采用超声分散法将制备的Er~(3+):Y_3Al_5O_(12)与Bi_2WO_6复合得到光催化剂Er~(3+):Y_3Al_5O_(12)/Bi_2WO_6复合物,利用X-射线衍射(XRD)和扫描电镜(SEM)对催化剂进行了表征.在(发出可见光的)三基色灯照射下,对罗丹明B的降解效果进行了一系列研究,如Er~(3+):Y_3Al_5O_(12)/Bi_2WO_6的煅烧温度,煅烧时间以及用量,光照强度,光照时间对罗丹明B降解率的影响.同时也考察了Er~(3+):Y_3Al_5O_(12)/Bi_2WO_6催化降解不同染料以及不同染料浓度的催化活性,并与单一的Bi_2WO_6的催化活性进行了对比.实验结果表明,催化剂的量为1.00 g/L,染料的初始浓度为10.00 mg/L,煅烧温度为350℃,煅烧时间为120 min时,对罗丹明B染料的降解效果最佳.     

磁性聚苯乙烯-苯甲氨二乙酸对Cu~(2+)富集性能的研究

为制备新型材料用于快速分离富集水中的微量铜元素,以磁性硅胶微球为核,N-(4-乙烯基)-苯甲氨二乙酸为单体,二乙烯基苯为交联剂,采用热引发聚合制备了磁性聚苯乙烯-苯甲氨二乙酸复合材料.通过傅里叶红外光谱、透射电镜和热重分析对复合材料的组成和结构特性进行了表征,并用Cu~(2+)研究了其富集性能和相关吸附动力学.结果表明:具有官能团的聚合物成功地包覆在了Fe_3O_4纳米粒子表面.10 mg吸附剂在pH值为5的10 m L Cu~(2+)溶液(25 mg·L-1)中,15 min达到吸附平衡且吸附率可达93%.Cu~(2+)在EDTA溶液(0.1 mol·L-1)中15 min可快速洗脱,洗脱率达95%.Cu~(2+)在材料上的吸附行为与准二级动力学模型拟合较好.     

化学预处理氧化铝自溶液中吸附SCN~-的研究

用不同浓度的HNO_3预处理Al_2O_3,制取pH为3.7～6.6的Al_2O_3吸附剂,在不同pH、浓度、时间、温度、共存电解质的条件下研究了Al_2O_3吸附SCN~-的规律和特性,并用离子交换机理所解释。近年来、对于氧化铝吸附含氧酸根SeO_4~(2-),CrO_4~(2-),PO_4~(3-)等的研究在国外已有报道,但对于HNO_3预处理氧化铝吸附SCN~-的研究尚未见到。而Al_2O_3大量存在于自然界中,SCN~-性质与卤素相似,能与许多金属络合。故我们用HNO_3预处理层析氧化铝研究了Al_2O_3在不同条件下吸附SCN~-的特性,并推断出该体系主要为离子交换吸附机理。这对于研究其他体系有所启示,并在分离提取、环境保护等实际应用中具有一定意义。     

三唑型磁性螯合树脂的合成、表征及吸附性能研究

采用化学共沉淀制备油酸包覆的纳米Fe_3O_4;在乙醇/甲苯溶剂中用分散聚合法制备微米级磁性聚甲基丙烯酸缩水甘油酯(PGMA-Fe_3O_4),然后用3-氨基-1,2,4-三氮唑对其进行化学修饰引入功能基团.经振动样品磁强计(VSM)检测,所制备的纳米Fe_3O_4和树脂具有超顺磁性;红外光谱(FTIR)证实了树脂的结构;通过扫描电镜(SEM)和透射电镜(TEM)观察,树脂具有微米级尺寸和核-壳结构.采用对几种常见金属粒子的24 h静态吸附来考察树脂的吸附选择性及吸附容量,发现树脂对Cu~(2 )有吸附选择性,最大吸附容量达3.24 mmol/g.     

阴离子对Al2O3吸附MoO4^2—的影响

本文报导了分别在磷酸盐、硅酸盐、硫酸盐、硝酸盐溶液中MoO_4~(2-)在中性Al_2O_3上的吸附情况,结果发现,MoO_4~(2-)的吸附量随着溶液的阴离子浓度和pH值而变化,其对吸附的影响情况与Hsu在酸性溶液中的结果是一致的.     

介孔纳米γ-Al_2O_3的制备及其对硫酸根离子的吸附性能研究

利用模板法合成介孔纳米γ-Al2O3,用透射电镜(TEM)、X射线衍射(XRD)、比表面测定(BET)等手段对所得的介孔纳米γ-Al2O3进行了表征.考察了介孔纳米γ-Al2O3在静态条件下对硫酸根离子的吸附性能.探讨了溶液的初始浓度、pH值、时间和温度对吸附性能的影响,结果表明:介孔纳米γ-Al2O3对硫酸根离子有较好的吸附性能,其吸附行为符合Freundlich等温式.     

介孔纳米γ-Al2O3的制备及其对硫酸根离子的

利用模板法合成介孔纳米γ=Al2O3,,用透射电镜(TEM)、X射线衍射(XRD)、比表面测定(BET)等手段对所得的介孔纳米γ-Al2O3进行了表征.考察了介孔纳米γ-Al2O3在静态条件下对硫酸根离子的吸附性能.探讨了溶液的初始浓度、pH值、时间和温度对吸附性能的影响,结果表明:介孔纳米γ-Al2O3对硫酸根离子有较好的吸附性能,其吸附行为符合Freundlich等温式.     

溶胶—凝胶法制备的钡铁氧体的微结构和磁性能

采用溶胶—凝胶法制备了M型纳米钡铁氧体(BaFe_(12)O_(19)),并进一步研究了不同pH值、煅烧温度和保温时间对样品微结构和磁性能的影响,用X射线衍射、扫描电子显微镜和振动样品磁强计对样品进行了表征和测量.当溶液pH在3以上时,比较容易生成BaFe_(12)O_(19)纯相,纯相样品的形貌基本为六角片状;样品的晶粒尺寸随煅烧温度的增大和保温时间的延长而变大;样品的磁性能与热处理温度有密切关系,1 200℃时样品磁化强度最佳:M_s=75.24 emu/g,M_r=35.18 emu/g;在950℃时矫顽力达最大值:H_c=3.33×10~5A/m.     

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