长炭纤维网对PEMFC用炭纸性能的影响

向炭纸初坯中引入长炭纤维网,以改性酚醛树脂为黏合剂对炭纸坯体进行浸渍,经模压固化、炭化和石墨化工艺制得质子交换膜燃料电池(PEMFC)用炭纸。研究长炭纤维的添加对炭纸性能的影响。研究结果表明:在兼顾炭纸具有优良透气性的前提下,长纤维的加入对炭纸起到了既增强又增韧的效果,并且提高了炭纸的导电能力;当添加的长炭纤维占炭纸初坯的10%(质量分数)时,炭纸的综合性能最好,其性能参数如下:厚度为0.23 mm,密度为0.47 g/cm3,电阻率为2.39 m-.cm,抗拉强度、抗弯强度及弯曲挠度分别为28.15 MPa,83.89 MPa和1.1 mm,孔隙率为75.8%,透气率为4 906.75 m3/(h.kPa.m),满足燃料电池气体扩散层用炭纸的需要。     

聚乙烯吡咯烷酮-镱(Ⅲ)配合物与鲱鱼精DNA的相互作用

采用UV-vis光谱法，在pH=7．00环境中用摩尔比法确定了鲱鱼精DNA与镱（Yb）的结合比nDNA：nYb=1：3，表观摩尔吸光系数ε=7．52×10^3L·mol^-1·cm^-1，聚乙烯吡咯烷酮（PVP）与鲱鱼精DNA-镱（Ⅲ）配合物（DNA（Yb）3）的结合比nPVP：nDNA（Yb）3=4：1，表观摩尔吸光系数ε=2．68×10^5·mol^-1·cm^-1。用双倒数法求得结合常数K^θ12℃=0．965×10^2L·mol^-1和K^θ22℃=0．218×10^2L·mol^-1，△H^θ，22℃=-1．04×10^5J·mol^-1，△rS^θm22℃=-3．27×10^2J·mol^-1·K^-1，△rG^θm22℃=-0．76×10^4J·mol^-1，该过程为焓驱动。确定了PVP—Yb（Ⅲ）与hsDNA之间为沟区作用方式。     

基于（Sn，Ba，La）·（P04）3C1．Eu纳米颗粒荧光猝灭法测定废水中Cr（VI）

基于Cr（VI）对（Sn，Ba，La）5·（PO4）3Cl·Eu纳米颗粒的荧光猝灭作用，建立了用琼脂溶液来固定分散（Sn，Ba，La）5·（PO4）3Cl·Eu纳米颗粒并用于测定水中微量Cr（VI）的荧光分析新方法．研究表明：Cr（Ⅵ）离子对固定于琼脂溶液中的（Sn，Ba，La）5·（PO4）5Cl·Eu纳米颗粒有荧光猝灭作用．在pH=9．0的条件下，测定的荧光最大激发波长和发射波长分别为271nm和447nm，测定Cr（VI）浓度的线性范围为4．0×10^-6mol／L^-1．4×10^-4mol／L，检测限为2．99×10^-6mol／L，回收率为98．9％～103．0％．方法具有良好的重现性和选择性，一些常见金属离子不干扰测定．应用于环境水中Cr（VI）离子含量的测定，结果满意．     

石河子大学学报(自然科学版)征稿简则

《石河子大学学报（自然科学版）》是石河子大学主办的自然科学综合性学术期刊,双月刊,132页,现设有农学·植物保护：园艺·林学、畜牧·兽医、医学·药学、生物·环境、食品·化工·材料、力学·水利·建筑工程、机械·电气工程、计算机技术·信息工程、数学·物理·化学10个栏目。     

石河子大学学报（自然科学版）征稿简则

《石河子大学学报（自然科学版）》是石河子大学主办的自然科学综合性学术期刊,双月刊,132页,现设有农学·植物保护、园艺·林学、畜牧·兽医、医学·药学、生物·环境、食品·化工·材料、力学·水利·建筑工程、机械·电气工程、计算机技术·信息工程、数学·物理·化学10个栏目。     

后经典叙事学的研究态势及其带来的思考：从首届叙事学国际会议谈起

2007年10月16-19日,第1届叙事学国际会议暨第3届全国叙事学研讨会在江西南昌召开。这是自2005年中国中外文艺理论学会叙事学分会成立以来首次召开的叙事学国际会议,吸引了众多国外知名叙事学家与会,如修辞性叙事学家詹姆斯·费伦GamesPhelan）、彼德·拉宾诺维茨（PeterJ．Rabinowitz）,女性主义叙事学家罗宾·沃霍尔（RobynWarh01）、萨吉塔·雷（SangeetaRay）,后现代叙事学家布赖恩·麦克黑尔（BrimMcHale）、     

猪卵母细胞第一极体排出与否对其早期胚胎发育的影响

探讨猪卵母细胞第一极体排出与否对其体外受精和孤雌激活后早期发育的影响．从屠宰场收集猪卵巢卵母细胞,体外成熟培养42-46h后分为3组：排出第一极体组、没有排出第一极体组和对照组（不挑选第一极体卵母细胞）,进行体外受精或化学孤雌激活之后放入胚胎培养液进行体外培养,分别于第48h和第168h统计分裂率和囊胚率．①体外受精后,有极体组的卵裂率略高于无极体组和对照组的卵裂率（62．19％±6．99％vs55．40％±6．80％和56．33％±8．17％）,各组间没有显著差异（P〉0．05）;囊胚率分别为4．87％±3．77％,2．33％±1．34％和3．50％±2．96％,有极体组明显高于无极体组（p〈0．05）,对照组与其它两组没有显著差异（p〉0．05）．②化学激活后,有极体组的卵裂率高于无极体组和对照组（75．45％±1．35％vs64．81％±2．07％和69．64％±2．51％,p〈0．05）;有极体组的囊胚率也高于无极体组和对照组（24．54％±4．34％vs12．96％±3．99％和18．75％±1．87％,p〈0．05）．排出第一极体卵母细胞比没有排出第一极体卵母细胞的发育能力强,但没有排出第一极体卵母细胞经体外受精或人工激活后也可以发育到囊胚阶段．     

各向同性煤沥青制备炭/石墨纤维的研究

以各向同性煤沥青为原料,采用熔融纺丝工艺制备了直径为55μm的沥青纤维,经预氧化、炭化和石墨化处理后得到炭纤维和石墨纤维,并采用偏光显微镜、XRD和SEM等对其形貌、结构和性能进行表征。结果表明,炭/石墨纤维具有与沥青原料相似的各向同性光学结构;随热处理温度升高,炭/石墨纤维截面逐渐变粗糙,且内部石墨微晶逐步发育并长大,3 000℃下石墨化纤维微晶增大较明显,其堆积高度和平面尺寸分别约为5nm和11nm;1 600℃炭化纤维的力学性能较好,其拉伸强度和杨氏模量分别达到0.57GPa和32.19GPa,进一步提高热处理温度,纤维拉伸强度逐步降低,但是其杨氏模量逐渐增加,3 000℃石墨化纤维的拉伸强度和杨氏模量分别为0.26GPa和40.57GPa;炭/石墨纤维室温轴向电阻率随热处理温度的升高而降低,1 000℃炭化纤维室温轴向电阻率为47.78μΩ.m,3 000℃石墨化纤维室温轴向电阻率降至21.98μΩ.m。     

硅橡胶膜渗透萃取脱除模拟废水中苯酚的研究

采用自制的硅橡胶（PDMS）平板膜制备成管式膜渗透萃取接触器处理含酚模拟废水，考察了苯酚的去除效果，并与硅橡胶管制成的卷绕式渗透萃取接触器和管式渗透萃取接触器进行了比较。实验结果表明：与硅橡胶管相比，PDMS平板膜的传质阻力减小，总传质系数提高，苯酚去除率、总传质系数和渗透通量分别为979，5、1．77×10^-1m·s^-1、5．73×10^-7g·m^-2·s^-1；硅橡胶管管式膜渗透萃取接触器较卷绕式膜渗透萃取接触器浓差极化小，且膜面积利用率高，硅橡胶管管式和卷绕式膜渗透萃取接触器总传质系数分别为1．25×10^-7m·s^-1和5．11×10^-8sm·s^-1。     

木质素热解/炭化官能团演变与焦炭形成

为了深入理解生物质热解/炭化过程,制备功能型焦炭,采用热重红外联用仪研究了木质素热解/炭化官能团演变与焦炭形成,并对所形成焦炭进行了导电性测试.实验结果表明:木质素热解/炭化过程分为4个阶段:200℃以下为自由水的脱除阶段;200～ 500℃为热解阶段,焦炭开始形成;500～900℃时焦炭中C-C键和C-H键进一步断裂,苯环大部分已被解链或芳香族化,形成无定形炭,在此阶段,焦炭的电阻率迅速下降,由986 Ω·cm减小到0.6 Ω·cm;900～1400℃时,碳碳双键几乎完全消失,焦炭内部结构重组,形成了一种介于无定型结构和石墨结构之间的新结构,电阻率达到0.2Ω·cm,导电性进一步增强.     

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.     

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.     

Tracking data management using topology of moving object database system for moving object constrained trajectory in LBS application

Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.