锌电积过程中锰元素对铝阴极的电化学行为影响

传统湿法炼锌工艺采用纯铝板作为阴极,但随着锌精矿品位的降低,电解液中杂质离子含量增大,造成阴极腐蚀消耗增加.本文以铝锰合金为研究对象,研究锰作为添加元素,与铝形成良好铝锰合金阴极材料的电化学行为,进一步提高铝阴极的耐蚀性和电催化活性.采用交流阻抗、阴极极化曲线、恒电流极化曲线、塔菲尔曲线等分析方法,探讨不同Mn元素含量对铝锰合金在40℃恒温条件,Zn2+65g·L-1和H2SO4150g·L-1溶液中电化学行为的影响.研究结果表明:相比纯铝电极,添加Mn元素的铝锰合金电极的耐蚀性普遍提高,腐蚀电流均减小;随着Mn含量的增加,腐蚀电流逐步降低,腐蚀电位与Mn含量增加无明显变化规律;当Mn质量分数为1.5％时腐蚀电流达最低(1.11mA·cm-2),腐蚀电位最小(-1.0954V);零电势下,表观电流密度i0受Mn元素的添加影响显著,i0随Mn含量增加呈现出先增大后减小的趋势,在Mn质量分数1.5％时达到最大值3.7462×10-16mA·cm-2,远大于纯铝电极4.8027×10-33mA·cm-2,整体变化幅度明显,电极的电催化活性得到提高;不同电流密度下的析氢过电位和纯铝电极的整体接近,电化学过程均为电化学传质步骤控制.综合考虑电极材料的耐蚀性和电催化活性,含Mn质量分数1.5％的铝锰合金可作为理想的电积锌阴极使用.     

石墨电极上电沉积钯镍合金的循环伏安研究

用循环伏安法对NiSO4 与PdCl2 混合溶液合成钯镍合金纳米线的电化学沉积条件进行了研究 .结果表明 ,钯镍离子混合液中钯的析出对镍、氢的电极过程有很强的去极化作用 ,使镍的析出电势正移 ,减小了钯、镍析出电势的差距 .钯离子浓度为 2mmol·L- 1,镍离子浓度为 0 .32mol·L- 1时 ,有利于形成钯镍合金 .高超电势和大电流密度下可以实现钯、镍共沉积 .但高浓度和高超电势下 ,电沉积的电流密度大 ,使金属的沉积速度过快 ,不利于形成钯镍合金纳米线 .钯镍析出电势相差较大 ,在低超电势条件下 ,难于实现共沉积 ,需通过加入添加剂或络合剂等其它方法来改变钯、镍的析出电势 ,使二者析出电势更进一步接近以达到共沉积的目的 .     

Sn对Mg-Al-Sn-Zn系海水电池用镁阳极材料组织及电化学性能的影响

采用金相显微镜、X射线衍射、扫描电镜和结合能谱仪研究了Sn对镁阳极材料显微组织、相结构、表面形貌及成分分布的影响;并通过恒电流法、动电位极化法和排水集气法等研究了该镁合金的腐蚀行为和电化学性能.结果表明:合金元素Sn的加入可以抑制棒状β-Mg17Al12相沿晶界析出,随着Sn含量的增大,颗粒相Mg2Sn增多;均匀化处理使大部分β-Mg17Al12相溶解,而残留Mg2Sn未溶相.Sn的加入可以提高镁合金自腐蚀电位和析氢率,当Sn质量分数为1%时镁合金阳极的放电电压和电流效率最大.析氢率随电流密度的增大而增大,当电流密度为20mA.cm-2时电流效率最高,可达82.28%.腐蚀产物主要成分为MgO和Al2O3,且疏松,易脱落,使镁合金阳极的工作电位负而且稳定,可促进电池反应深入进行.     

钯—泡沫镍电极电催化还原脱硝络合液的研究

Fe(Ⅱ)EDTA络合脱硝技术是烟气脱硝技术中较为常用的一种方法.然而,Fe2＋易氧化,损失较大,二次使用困难,导致运行成本高.为了达到络合液重复利用的目的,利用钯－泡沫镍电极对脱硝络合液进行电催化还原再生,主要探究催化剂的负载量、电流密度及反应温度对钯－泡沫镍电极的电催化再生效果的影响.实验结果表明：当采用化学置换将钯负载在泡沫镍电极,负载量为1.0 mg·cm－2,电流密度为6 mA·cm－2、温度为30 ℃时,再生效果最好,Fe(Ⅱ)EDTA－NO的转换率达90.0%、NH选择性为10.0%、N2的选择性为90.0%、再生液对NOx脱除效率在25 min内均大于80%.     

直接黄11染料电渗析脱盐

采用电渗析法对直接黄11染料进行脱盐纯化,考察了电流密度、染料液室流量、染料质量浓度、盐的质量分数及pH值等对直接黄11染料电渗析脱盐过程的脱盐率与染料损失率的影响。实验表明,电渗析可有效脱除染料中的无机盐,在实验的电流密度1.5~5.0 mA/cm2、染料室流量0.12~0.21 L/min、染料质量浓度4~16 g/L、盐的质量分数5%~20%及pH3.8~12范围内,直接黄11染料液的脱盐率均达到99%以上,染料损失率小于2%。     

纳米多晶镍钨合金力学性能的分子动力学研究

为了研究钨原子分数与平均晶粒尺寸对镍钨合金纳米多晶力学性能的影响，本文运用分子动力学方法在10 K与300 K时对镍钨合金纳米多晶模型进行拉伸与剪切模拟，计算分析了不同钨原子分数(0%、5%、10%、15%、20%)的镍钨合金的抗拉强度、延伸率与抗剪切性能等力学性能，进一步研究了不同晶粒尺寸(2.4 nm、1.9 nm、1.5 nm)对镍钨合金多晶力学性能的影响。结果表明，当镍钨合金纳米多晶中钨原子分数为0%时，在10 K或者300 K时，平均晶粒尺寸小的镍钨合金纳米多晶抗拉强度大，但是抗剪切强度反而小；当镍钨合金纳米多晶中钨原子分数在0%～20%之间时，随着钨元素含量的增加，抗拉强度与抗剪强度也逐渐增大；当镍钨合金纳米多晶中钨原子分数在0%～15%之间时，温度为10 K或者300 K时，平均晶粒尺寸为1.5 nm的镍钨合金纳米多晶的延伸率大于平均晶粒尺寸为1.9 nm或者2.4 nm的镍钨合金纳米多晶的延伸率。     

乙二醛电氧化制备乙醛酸的研究

以间接氧化技术电化学法合成乙醛酸.Br-在阳极上氧化生成Br2,继而以Br2作媒介,间接氧化乙二醛生成乙醛酸,同时Br2被还原为Br-,从而实现了溴的循环使用.研究了氧化媒介、电流密度、温度、乙二醛初始浓度等因素对氧化过程的影响.实验表明,在电流密度为25 mA·cm-2,反应温度为(30±5)℃,乙二醛初始质量分数为10%～25%,氢溴酸质量分数为10%的条件下,电流效率75%～83%.     

InGaN p-i-n同质结太阳能电池性能的理论分析

基于复合速率连续性方程,理论分析了InGaN p-i-n同质结太阳能电池的性能.结果表明,随着In组分含量增加,载流子收集效率、填充因子和开路电压均减小,短路电流密度增大,这些因素导致太阳能电池转换效率先增大后减小.当In摩尔分数大约为0.6时,太阳能电池转换效率达到最大.当缺陷密度低于1016 cm-3时,缺陷密度对载流子收集效率和短路电流密度几乎没有影响,而当缺陷密度高于1017 cm-3时,随着缺陷密度增大,载流子收集效率、短路电流密度、开路电压、填充因子和转换效率均减小.In摩尔分数越高,缺陷密度对太阳能电池性能的影响越大.     

熔盐电解二氧化硅制备低硼磷铝硅合金

分别采用高纯石墨和Fe-Ni合金为阳极,在960℃的冰晶石熔盐中电解SiO₂制备低硼磷铝硅合金,研究电流密度和SiO₂添加量对电流效率、阴极产物成分和B,P杂质含量的影响规律,并利用XRD和SEM表征阴极产物的物相组成和微观形貌.结果表明,以石墨为阳极时,当电流密度从0.5A/cm²增大到0.9A/cm²时,阴极产物中w［Si］从0.75%增大到15.17%,电流效率从2.58%增大到38.06%;B和P的最低质量分数分别为3×10^-6和7×10^-6.以Fe-Ni合金为阳极时,当SiO₂添加量从2%增大到6%时,阴极产物中w［Si］从3.19%增大到19.86%,电流效率从12.43%增大到70.48%;B和P的最低质量分数分别为6×10^-6和11×10^-6;阴极产物的物相组成为铝、硅和铝硅合金.     

哈氏合金表面脉冲电镀镍层的制备及其耐蚀性能

采用双脉冲电镀法在哈氏合金表面制备了纯镍涂层,主要研究了正向脉冲电流密度和正向周期对电镀镍层质量的影响及其耐熔盐腐蚀性能.结果表明:随着正向电流密度和正向周期的增加,镀层厚度增大,显微硬度呈先增后减的趋势.在本实验条件下,当正向电流密度为30 A/dm2、正向周期为70 ms时,镀层质量较好.哈氏合金基材和镀镍涂层的哈氏合金试样的腐蚀失重分别为0.083 7 mg/mm2和0.053 1 mg/mm2,基材经熔盐腐蚀后由于Cr元素大量流失而呈现典型的沿晶腐蚀特点,但镀镍试样经腐蚀后镀镍层仍与基材紧密结合,基体区组织未发生明显变化,优化制备的电镀纯镍涂层显著提高了哈氏合金基体的耐熔盐腐蚀性能.     

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.     

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.     

A computer generator for randomly layered structures

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

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。     

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     

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     

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

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.