温度对煤造气制备碳化铁的影响

研究了以煤造气为还原剂制备碳化铁过程中温度对还原度、金属化率、碳化铁率的影响,实验条件为压力0.3 MPa、反应时间180 min、还原气体中CO/CO2分别为3和1.5,反应温度在550～700℃之间变化.通过实验研究得到如下结论:产物的还原度、金属化率随温度的升高而逐渐增大;碳化铁率在600℃时最小;在气体成分达到一定还原势(CO/CO2=3)的条件下,700℃时碳化铁率最高;而在CO/CO2=1.5时,高温下不利于碳化铁的生成.     

烯(火圣)醛化和羰化的新催化剂

研究了钌簇合物Ru_1(CO)_(12),H_4Ru_4(CO)_(12)[PPN][HRu_1(CO)_(11)],[PPN][H_3Ru_4(CO)_(12)](PPN=[(Ph_2P)_2N]~)和Ru_2(CO)_2.(dpm)_3(dpm=ph_2p-m-C_4H_4SO_3Na)等摧化乙烯的醛化,报道了可溶性的Ru_3(CO)_2(dpm)在水溶液中催化丙烯和乙烯的醛化、羰化的性能,在反应温度120℃,反应气体总压为2.7～5.OMPa的条件下,丙烯和乙烯的醛化活性随反应温度、催化剂浓度和气体分压(CO/H_2=1:1)的提高而提高,温度的变化对活性的影响最明显,溶液的酸碱性也影响催化活性,中性对反应最有利,添加无机和有机卤化物显著地影响乙烯的醛化活性和产物分布,乙烯羰化生成二乙基酮的选择性高达52.7％,其反应前后的钉簇合物催化剂分别经IR和XPS表征,讨论了可能的催化活性物种。     

固态原位电还原TiO_2制取Ti的阳极和电极过程

运用循环伏安法对固态原位电还原TiO2制取Ti的阳极过程进行了研究,并分析了整个电极反应过程.研究发现,固态原位电还原TiO2制取Ti的阳极过程是一步二电子氧化反应,并且可逆,产物不熔,在石墨阳极下生成CO2气体,阳极电极反应:C+2O2--4e=CO2.固态原位电还原TiO2制取Ti的总电极反应为:2TiO2+C=2TiO+CO2,2TiO+C=2Ti+CO2,2CaO+C=2Ca+CO2.阴极生成的Ca可以继续对TiO2进行热还原反应,固态原位电还原TiO2制取Ti是TiO2的直接二步电还原与Ca热还原TiO2共同作用的结果.     

丁酸甲酯高温分解的过渡态理论研究(英文)

选取了丁酸甲酯高温分解的十三个反应路径中较为重要的两个反应:CH3OCO=CH3+CO2(R1)和CH3OCO=CH3O+CO(R2).使用密度泛函理论方法在B3LYP/TZVP基组水平上寻找了反应的过渡态,并且得到了两个反应的势能曲线.R1的势垒高度远远低于R2,同时R1的产物CH3和CO2拥有较低的能量,处于相对稳定的状态.因此,反应CH3OCO=CH3+CO2更容易发生.结论为丁酸甲酯的动力学模型研究提供了一定的理论依据.     

ZrO2改性Co-Ru/γ-Al2O3催化剂F-T合成的本征动力学

根据费-托(F-T)合成的表面碳化物机理,推导出合成气反应的8个动力学模型.利用固定床微分反应器对ZrO2改性Co-Ru/γ-Al2O3催化剂在473 K和458～498 K下的F-T合成动力学进行了研究.结果表明:473 K时,H2完全解离,吸附态CO加氢生成甲酰(HCO),HCO加氢生成表面C,同时氧以水的形式脱除(模型6),实验结果最吻合.在473K时,反应速率表达式为:-dNCO/dw=kpCOp1/2H2/(1 1.499p1/2H2 1.609pCO 2.541p-1/2H2pCO)2,k为99.83 mmol/(h·g·MPa1.5).通过实验数据对模型6的非线性回归,对反应活化能、吸附活化能等进行了估算,活化能为68.34 kJ/mol.     

气体放电等离子体直接转化CH4和CO2制备高碳烃研究

针对温室气体CH4和CO2化学利用,提出介质阻挡气体放电等离子体化学转化方法,将CH4,CO2直接转化为高碳烃,并副产一部分合成气.实验表明,介质阻挡气体放电CH4和CO2反应烃类产物类似于常规催化的Fischer-Tropsch(F-T)合成,包括气态烃、液态烃和高聚物,但产物分布不符合Flory-Schulz分布.研究讨论了分子筛在抑制等离子体聚合物和炭黑生成方面的作用,讨论了CO2进料对CH4转化制高碳烃的影响,指出适宜进料CH4/CO2比在2/1至3/1范围内.     

Pt 电极上 CO2水解析氢反应的研究

利用循环伏安法,研究了CO2-H2O 体系在 Pt 电极上的析氢反应,与单纯析氢反应相比,还原峰电位发生负偏移,还原峰电位为-0.5,V.并通过计算,得出在 pH=4附近 CO2扩散系数D =3.02×10-10,m2/s,H+扩散系数CO 2 D =+H 4.93×10-9,m2/s,电极表面的反应层厚度D k cμ=/(0 b-及 H+的浓度分布函数) c c++ΗΗ[-=10 H+HCO exp{-x k c 0 b HCO-/D +H}].33为电流法测定 CO2气体浓度的方法提供了基础参考数据     

添加氯离子对Ni/CeO2催化剂CO选择甲烷化反应催化性能的促进

采用浸渍方法制备NiO(Cl_x)/CeO₂系列样品,经还原后得到Ni(Cl_x)/CeO₂催化剂,用于富氢气体中CO的选择甲烷化反应,考察Cl/Ce原子比(x)对CO选择甲烷化反应活性的影响. 结果表明,添加氯离子能够显著抑制CO₂甲烷化反应,因而可使富氢气体中CO浓度降至10-5以下并且CO甲烷化反应选择性不低于50%,满足质子交换膜燃料电池对燃料的要求. 通过CO和CO₂吸附实验、程序升温还原(TPR)测定以及物相组成和晶粒尺寸分析,揭示添加氯离子的作用.      

ZrO_2改性Co-Ru/γ-Al_2O_3催化剂F-T合成的本征动力学

根据费-托(F-T)合成的表面碳化物机理,推导出合成气反应的8个动力学模型。利用固定床微分反应器对ZrO2改性Co-Ru/-γA l2O3催化剂在473 K和458~498 K下的F-T合成动力学进行了研究。结果表明:473 K时,H2完全解离,吸附态CO加氢生成甲酰(HCO),HCO加氢生成表面C,同时氧以水的形式脱除(模型6),实验结果最吻合。在473K时,反应速率表达式为:-dNCO/dw=kpCOp1H/22/(1 1.499p1H/22 1.609pCO 2.541p-H2 1/2pCO)2,k为99.83 mm o l/(h.g.M Pa1.5)。通过实验数据对模型6的非线性回归,对反应活化能、吸附活化能等进行了估算,活化能为68.34 kJ/m o l。     

基于Gibbs自由能最小原理分析CO2重整CH4

运用G ibbs自由能最小方法,研究了重整反应器的操作参数(温度、压力、反应气配比等)对CO2重整反应中CH4转化率和产物分布的影响,以及甲烷氧化反应与CO2重整反应间的能量耦合.研究结果表明:反应压力P不变(P=101.325 kPa),随温度升高CH4和CO2转化率增大,在900 K左右产生的H2O(g)的量达到极大值,在1 200 K以上CH4转化率接近100%;反应温度T不变(T=973 K),随压力升高CH4和CO2转化率降低,H2O(g)的选择性略微增加;T=973 K,P=101.325 kPa,原料气中nCH4/nCO2(摩尔比)从0.65增加到2.0时,CH4转化率从85%降到45%,nH2/nCO(摩尔比)从0.77增加到0.95;反应器中加入适量O2,可以提供CO2重整反应所需的能量,同时可调节产物中CO与H2的摩尔比.     

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