氢对X80钢在库尔勒土壤模拟溶液中应力腐蚀开裂行为的影响

采用电化学充氢技术、动电位扫描技术、交流阻抗技术(EIS)和慢应变速率拉伸试验(SSRT)研究库尔勒土壤模拟溶液中氢对X80管线钢应力腐蚀开裂(SCC)行为的影响,并利用扫描电镜(SEM)观察试样断口形貌。研究结果表明:充氢电流密度和充氢时间的增加均能加速金属腐蚀反应;随着充氢量的增大,试样自腐蚀电位呈下降趋势,腐蚀速率逐渐增大,氢促进了X80钢在库尔勒模拟溶液中腐蚀的发展;电化学充氢后,X80钢的应力腐蚀开裂行为主要由氢致开裂(HIC)作用决定,阳极溶解过程只起到辅助裂纹形核的作用,因为氢能引起材料局部塑性变形,促进裂纹尖端形核和扩展。     

碳钢在我国四种土壤中腐蚀机理的研究

利用Q235钢在我国四种典型土壤（即大庆中心站苏打盐土、大港中心站滨海盐渍土、新疆中心站沙漠戈壁土、华南站酸性土）中进行室内模拟加速腐蚀试验和电化学实验，并对腐蚀试验后的腐蚀产物进行了微观分析和微生物分析。研究结果表明，碳钢在上述四种土壤中的腐蚀过程为：阳极过程为铁的溶解，非晶态羟基氧化铁的生成，经生化最终成为褐铁矿；阴极过程为氧去极化为主要的扩散控制过程。华南土pH值较低，同时伴随着氢去极化腐蚀的阴极过程。大港土中检测出少量的FeS，这是由于SRB参与氢去极化过程的结果。腐蚀过程受阴极极化控制，扩散控制程度随试验土样温度的升高和含水量的增大而增大。     

X80管线钢在近中性pH溶液中的应力腐蚀开裂

采用电化学动电位扫描技术、慢应变速率拉伸(SSRT)试验和扫描电镜观察研究了X80管线钢及焊接接头在NS4溶液中的应力腐蚀行为.电化学实验结果显示,X80管线钢及焊接接头在NS4溶液中的极化曲线具有典型的活性溶解特征.SSRT试验结果表明,随着外加电位的负移,断裂时间、断面收缩率、应变量都明显变小,X80管线钢及焊接接头的应力腐蚀开裂敏感性增加,应力腐蚀断口呈现穿晶准解理特征.施加相同外加电位时,焊接接头较母材的应力腐蚀敏感性增加,其断裂位置全部落在焊缝或HAZ处.     

外加电位对X80管线钢模拟海岸土壤腐蚀的影响

为探究双相X80管线钢在沿海土壤模拟溶液环境中的腐蚀机理，采用极化曲线、慢应变速率拉伸试验(SSRT)和交流阻抗(EIS)法对不同外加电位(-750,-900和-1 050 mV vs.饱和甘汞电极(SCE))下双相X80管线钢的应力腐蚀和电化学腐蚀行为进行研究。结果表明，双相X80管线钢在-1 050 mV电位下对应力腐蚀(SCC)最为敏感。慢应变拉伸呈现为脆性断裂，断口可见铁素体区域圆形或椭圆形的凹坑，这是由于过度阴极反应产生的氢原子扩散进入到钢中在铁素体晶界聚集，氢气析出产生的较高氢压超过材料的强度产生圆形孔洞，在拉伸应力作用下变为椭圆形。在此电位下EIS模拟电阻最小，耐腐蚀性最差。-750 mV的外加电位可起到一定的电化学保护作用，但不足以防止X80管线钢应力腐蚀的发生。-900 mV的外加电位可有效抑制X80管线钢的阳极溶解，SSRT的强度和延展性均高于0 mV电位试样，表现出韧性断裂特征，EIS模拟电阻最高，因此双相X80管线钢在模拟海岸土壤环境下最佳的阴极保护电位约为-900 mV vs. SCE。双相X80管线钢在沿海土壤模拟环境中的应力腐蚀行为的研究可对其在实际使用过...     

AZ31镁合金表面羟基磷灰石涂层的制备和表征

以氢氧化钙和磷酸二氢钙为前驱物,在AZ31镁合金表面通过溶胶凝胶法制备了羟基磷灰石涂层。利用X射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)对涂层的物相组成、表面形貌、截面进行了分析表征,利用电化学工作站测试了该涂层在生理盐水中的动电位极化曲线和电化学阻抗谱,并对涂层在Hank’s模拟体液中的析氢量和浸泡腐蚀形貌进行了表征。结果表明,溶胶凝胶法制备的羟基磷灰石涂层纯度较高,结晶性良好,涂层厚度在8μm左右;动电位极化曲线结果显示,该涂层的腐蚀电流密度为1.486 4×10-2 mA/cm2,与空白镁合金的腐蚀电流密度相比降低了5倍左右。析氢试验及其浸泡腐蚀形貌进一步说明羟基磷灰石涂层能有效地保护镁合金基体。     

X70管线钢焊接接头组织及其海水腐蚀规律

对X70管线钢现场实际焊接工艺下的焊接接头,采用显微镜、电化学方法及失重法等方法和手段对母材、焊缝、热影响区进行了显微组织分析和在海水中的极化曲线、腐蚀速率的测试,研究焊接接头在模拟海水环境中的腐蚀性能。研究表明,X70管线钢焊接接头各区域组织不均匀,实验室模拟海水环境下的电化学行为、腐蚀速率存在明显差异;在海水腐蚀过程中腐蚀电位和腐蚀速率会发生变化,热影响区（HAZ）与母材及焊缝形成电偶腐蚀,接头腐蚀以点蚀为主。     

X70钢在模拟大气腐蚀水中的腐蚀行为研究

采用极化曲线法和交流阻抗法研究了X70钢在含0．5g／L的Na2SO4、Na2CO3、NaCl模拟大气腐蚀水中的电化学行为．结果表明：随着浸泡时间的延长,X70钢腐蚀速率逐渐降低;液膜厚度在1000—800μm时,阴极极限扩散电流变化不大,液膜厚度小于800μm时,阴极极限扩散电流剧增．随着液膜厚度减薄,X70钢腐蚀速率呈增大趋势．     

钙离子的浓度对X80钢腐蚀行为的影响

采用失重法、电化学测试、扫描电镜、X射线衍射等方法研究了钙离子浓度对X80钢在哈密土壤模拟溶液中的腐蚀行为影响.在60 d浸泡期内,X80钢在不同钙离子浓度模拟溶液中的腐蚀形态均为全面腐蚀,腐蚀产物都为β-FeOOH;X80钢在模拟溶液中的腐蚀速率随钙离子浓度的降低而呈逐渐增大的趋势.在180 d浸泡期内,在钙离子浓度为63.5 mmol·L-1的模拟溶液中,钙盐随时间的增加在X80钢基体表面不断结晶析出;钙盐层有效阻碍了溶解氧的迁移,并促进其覆盖区域下形成氧浓差电池,最终导致基体表面点蚀的萌生.同时,在内层腐蚀产物表面连续析出的钙盐层的致密性也随时间不断得到改善,在一定程度上起到了抑制氯离子和溶解氧对基体的侵蚀作用,X80钢的全面腐蚀逐渐减缓.     

X65钢CO2腐蚀产物膜电化学行为研究

在模拟油田CO2腐蚀环境下,利用失重法、极化曲线及交流阻抗技术研究了X65钢在不同腐蚀时间和不同温度下形成的腐蚀产物膜特征。结果表明,腐蚀产物膜的生成可以显著降低腐蚀电流密度;从65℃,75℃到90℃时,随着温度的升高,腐蚀速率逐渐下降;从90℃到115℃时,腐蚀速率又开始上升。不同腐蚀时间电化学阻抗谱(EIS)曲线主要有高频容抗弧、低频感抗弧和低频容抗弧,其中低频感抗弧与试样表面活化溶解有关,低频容抗弧与试样表面腐蚀产物膜的生成有关。随着温度的升高,腐蚀产物膜的交流阻抗谱形状发生了变化。     

SO42-对X80管线钢在库尔勒土壤模拟溶液中腐蚀行为的影响

采用动电位极化和交流阻抗技术研究在库尔勒土壤模拟溶液中SO42-质量分数对X80管线钢腐蚀行为的影响,并利用金相显微镜观察不同SO42-质量分数下的腐蚀形貌.结果表明:X80管线钢在SO42-不同质量分数的库尔勒土壤模拟溶液中,其极化曲线呈现典型的活化溶解特征;随着SO42-质量分数的增加,X80钢的腐蚀速率呈现先增大、后减小的趋势;当SO42-质量分数为5％时,极化电阻Rp出现临界值,此时X80管线钢的腐蚀最严重;当SO42-质量分数为10％时,金属腐蚀反应严重受阻,其表面腐蚀现象不明显,只有几个小的腐蚀坑存在;溶液中的Cl-吸附在X80钢表面会导致金属发生腐蚀自催化过程;而SO42-优先于Cl-吸附在金属表面上,能够抑制Cl-对X80管线钢的腐蚀行为.     

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。     

A computer generator for randomly layered structures

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

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.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

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.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with