粉末冶金法制得的白口铸铁的超塑性研究

通过快速结晶法制得了2.875％C+1.3％Cr的白口铸铁粉末。然后用热等静压方法在温度720℃,压力150MPa将粉末压3h得到了高密度的粉末压块。压块经63％的变形后,显微组织由晶粒尺寸为1～3μm的铁素体和直径小于3.5μm的渗碳体颗粒组成。在670～770℃的温度区间和3×10~(-4)～1~(s-1)的应变速率范围,对材料在热等静压后和热等静压+63％的墩粗变形后的超塑性行为进行了研究。研究结果表明:材料在720℃和3×10~(-3)～3×10~(-2s-1)的应变速率下显示出低的流动应力和高的应变速率敏感性(m=0.42)。     

毛细管电泳电化学检测葛根和葛藤中几种黄酮类化合物

用毛细管电泳电化学检测法测定了葛根和葛藤中葛根素、大豆甙元和芦丁含量.以碳圆盘电极为检测电极,电极电位为0.90V(vs.SCE),在50mmol/L硼酸盐缓冲液(pH9.0)中,使用长40cm熔融石英毛细管,当分离电压为9kV,上述三组分在12min内完全分离.葛根素、大豆甙元和芦丁浓度与电泳峰电流分别在2.5×10-6～1.0×10-3,1.0×10-6～1.0×10-3和5.0×10-6～1.0×10-3mol/L范围内呈良好线性,检出限(S/N=3)分别为3.4×10-7,2.4×10-7和5.1×10-7mol/L.7次测定葛根素、大豆甙元和芦丁的混合标准溶液,峰高的相对标准偏差分别为2.71%,2.47%和4.21%.     

二甲酚橙—溴化十六烷基三甲胺与铜（Ⅱ）钴（Ⅱ）的光度法研究及铜的测定

本文研究了二甲酚橙(XO)-溴化十六烷基三甲胺(CTMAB)与铜(Ⅱ)、钴(Ⅱ)的显色反应.结果表明在pH8.0,溴化十六烷基三甲胺存在时,铜(Ⅱ)、钴(Ⅱ)与二甲酚橙能形成稳定的络合物.其最大吸收波长均为590nm,摩尔吸光系数分别为6.9×104L·mol-1·cm-1和3.6×104L·mol-1·cm-1.铜(Ⅱ)含量在0～15.1μg/25mL内,钴(Ⅱ)含量在0～18μg/25mL内符合比尔定律.线性方程及回归系数分别为A=4.765×10-3+0.0185C,γ=0.9962;A=3.005×10-3+7.481C,γ=0.9966.应用本法测定了铅合金标样中的微量铜.     

聚组氨酸修饰电极测定多巴胺的研究

本文研究了多巴胺在聚组氨酸修饰电极上的循环伏安行为.在pH7.0的磷酸盐缓冲溶液中,用线形扫描伏安法测定多巴胺的线性范围为:6.0×10-8～1.0×10-5mol/L,1.5×10-5～1.0×10-3mol/L,检出限为4×10-8mol/L.用于药剂中多巴胺的测定,结果满意.     

流动注射化学发光增强法测定酪氨酸

在Na2CO3-NaHCO3介质中,酪氨酸对Luminol-K3Fe(CN)6化学发光体系有很强的增敏作用.据此建立了流动注射化学发光增强法测定酪氨酸的方法.发光信号的增强值(ΔI)与酪氨酸的浓度在5.0×10-5～4.0×10-7mol/L的范围内呈良好的线性关系,检出限为1×10-7mol/L(S/N=3),对于1.0×10-6mol/L的酪氨酸测定相对标准偏差为2.4%(N=11).该法用于测定医用氨基酸注射液中的酪氨酸,结果令人满意.     

微分电位溶出法测柠檬酸

报道了微分电位溶出法 (DPS)在 0 .1mol/LHAc -NaAc介质中测定柠檬酸 .在选定条件下 ,于4 .0× 10 - 5～ 8.0× 10 - 3mol/L范围内有较好的线性关系 ,r =0 .9893,检测限为 1.0× 10 - 5mol/L .用于常见汽水测定 ,结果满意     

离子对反相高效液相色谱法测定VB2,VB6,VB12,VC和叶酸

建立了用离子对反相高效液相色谱法同时测定VB2,VB6,VB12,VC和叶酸含量的方法.用HypersilC18色谱柱(ODS2,5 μm,4.6 mm×150 mm,),V(甲醇)V(0.5%醋酸溶液)=3070,其中每升流动相加入2.5 mmol的戊烷磺酸钠作为流动相.柱温30℃时于254 nm波长处以外标法测定.结果表明VB2,VB6,VB12,VC和叶酸的浓度与峰高成良好的线性关系.VB2的线性范围为2.0×10-7～8.0×10-6g/mL(r=0.999 8),VB6的线性范围为2.0×10-6～5.0×10-4g/mL(r=0.999 0),VB1 2的线性范围为2.0×10-7～8.0×10-4g/mL(r=0.999 9),叶酸的线性范围为2.0×10～5.0×10-5g/mL(r=0.998 7),VC的线性范围为5.0×10-7～8.0×10-5g/mL(r=0.999 1).VB2,VB6,VB12,VC和叶酸的检测限分别为6×10-9g/mL,6×10-8g/mL,7×10-9g/mL,1×10-9g/mL和6×10-8g/mL实验表明该法准确,快捷,操作简便,应用于蜂蜜和复合维生素片中维生素的测定,取得了很好的结果.     

极谱法连续测定痕量铅和镉

研究了Pb2+和Cd2+与KCI-酒石酸钠-三乙醇胺-明胶体系的二次导数极谱波.在pH=4.5的HAc-NaAc介质中,Pb2+和Cd2+分别于-0.46V和-0.64V电位处产生一良好的极谱波.峰电流与Pb2+和Cd2+的浓度分别在1×10-5～3×10-1 g·L-1和5×10-5～6×10-3 g·L-1范围内呈线性关系.Pb2+和Cd2+的检出限分别为1×10-7 g·L-1和5×10-7 g·L-1.本法准确、简便、快速、选择性高.已直接用于饮料中铅和镉的连续测定,同时也对酒及面粉样品进行了测定,回收率分别为99.9%～100.1%和97.0%～104.8%.     

单扫描示波极谱法测定保健食品中的叶酸

建立了保健食品中叶酸的单扫描二阶导数示波极谱测定方法,并用正交条件试验确定了测定叶酸的最佳底液条件.在B R(Britton Robinson)缓冲体系(pH=7.22)中,叶酸产生一灵敏的极谱还原波,峰电位Ep=-0.89V(vs.SCE),其二阶导数波峰电流与叶酸浓度在3×10-7～5×10-6mol L范围内呈线性关系,线性方程i″p=59.441c+9.627,相关系数r=0.9991,检出极限为3×10-7mol L.     

{MoOS3Cu3 （PPh3）3Cl}的合成及晶体结构

本文合成并测定了{MoOS_3Cu_3(PPh_3)C1}的晶体结构,簇合物属正交晶系,空间群为P_(212121)晶胞参数:a=12.833(5)×10~(-10)m,b=17.552(5)×10~(-10)m,c=22.778(7)×10~(-10)m;Z=4。结构用直接法解出,经最小二乘法修正,偏离因子R=0.069.     

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