汽车驾驶员疲劳状态下穴位磁刺激效应分析

在驾驶员疲劳状态下，应用心率变异性(HRV)功率谱分析，评价穴位碰刺激对自主神经系统功能的调整作用．健康志愿人员26名，每人参加两组模拟驾驶实验，A组为磁灸组，B组为对照组，时间均为90min．对磁灸组志愿者，在执行驾驶任务1h后，施加磁刺激30min．实验过程中实时记录实验者心电信号．执行任务过程中，实验者心率变异性表现出明显的线性趋势．磁灸组施加穴位磁刺激后，实验者表现为交感神经活动性降低，迷走神经活动性提高，精神紧张及疲劳程度降低．穴位磁刺激有利于改善心脏自主神经系统功能状态，可在一定程度上缓解精神疲劳．     

磁刺激对大鼠心电的影响及分析

为研究胸闷、心疼痛等疾病的机理,分析磁刺激导致心电变化的原因,选择大鼠若干只,接受不同频率不同强度的脉冲磁刺激,监测刺激开始前?进行中和结束后的心电信号,比较无外加刺激和刺激进行时?刺激结束后的异同;比较了施加不同强度不同频率刺激时心电的异同.结果表明,刺激进行时,在脉冲作用的瞬间,大鼠心电幅值超出无刺激时心电的若干倍,且频率一定时心电幅值随着线圈电流变化率的增大而增大;刺激结束后,刺激对心电的残余影响将随着刺激频率的逐渐降低而加剧.所以合适强度频率的磁刺激将会对恢复心肌功能、治疗心肌疾病产生积极的作用.     

吹吸扰动对湍流边界层多尺度相干结构的影响

用IFA-300热线风速仪以高于对应最小湍流时间尺度的分辨率，精细测量了风洞中施加局部周期性吹吸扰动平板湍流边界层近壁区域不同法向和流向位置的瞬时速度的时间序列信号．对平板湍流的扰动是通过平板上沿展向分布的一条窄缝引入的正弦振荡产生的．用子波分析对壁湍流脉动速度信号进行多尺度分解，用子波系数的瞬时强度因子和平坦因子检测壁湍流多尺度相干结构，并提取不同尺度相干结构的条件相位平均波形，研究不同频率的吹吸扰动对平板湍流边界层多尺度相干结构的影响，结果表明，扰动对边界层近壁区域平均速度分布、能量随尺度分布以及多尺度相干结构及其条件相位平均波形，都有显著影响，其中32Hz扰动影响最大．     

铜锟的转速对Pr9Fe74Co12B5快淬条带的磁性能的影响

本文研究了铜辊的转动频率对Pr9 Fe74 Co12 B5快淬条带的磁性能的影响．实验结果表明，当铜辊转动频率为36Hz时，Pr9 Fe74 Co12 B5快淬条带具有最佳的磁性能：Jr=1.18T，μ0Hc=0.55T,（BH）max=19.96MGOe.直接快淬不经热处理的条带亦可具备较好的磁性．     

磁致伸缩超声导波的包覆层轻烃管道检测试验分析

采用磁致伸缩传感器(Ms S)超声导波检测系统,对带包覆层轻烃管道进行在线检测。研究了不同检测频率、管道直径对管道缺陷检测定位精度的影响,并分析了带有黏弹性包覆层环氧树脂对超声导波信号的影响。对114 mm和80 mm两类管道,以三通、弯头等近似为缺陷,分别使用32 k Hz和64 k Hz探头进行检测。检测结果表明:不同检测频率时管道缺陷检测精度不同,频率越高,定位精度越高。管道的直径对导波信号缺陷检测精度有重要影响,采用32 k Hz频率对80 mm管道的定位精度为9.3 cm,远高于114 mm管道的定位精度(17.6 cm)。黏弹性包覆层对检测信号有强烈的衰减,平均衰减速率约为1 d B/m。     

Agrotis segetum雄蛾触角叶神经元的时相编码特性

应用细胞内记录神经放电方法 ,研究Agrotissegetum雄蛾触角叶MGC神经元对性信息素的反应特征及时相编码特点。在此种雄蛾MGC中 ,投射神经元对性信息素的反应呈现一种双相反应模式。 2 6个MGC神经元均可对 1,3Hz频率的每个刺激有明显的双相反应 ,14个神经元可对 5Hz频率的每个刺激引起明显的双相反应 ,4个神经元仅能识别 7Hz频率的每个刺激 ,1个神经元可识别高至 10Hz频率的每个刺激。神经元对性信息素频率刺激的反应能力与神经元自发放电频率、反应时的超极化幅度等都有一定的相关关系     

漏磁检测的交直流磁化问题

针对漏磁检测交流磁化的磁化电流频率选择问题 ,采用概率论的有关知识分析了影响漏磁检测信号大小的因素 ,并从漏磁场的检测理论上分析了磁化频率的选取原则 ,即 :载波频率应远大于调制波频率。对宽 0 .2 mm、深0 .2 m m的人工矩形槽缺陷的检测结果验证了对缺陷漏磁场所作的理论分析 ,得出了在常规的漏磁检测条件下磁化频率应大于 1k Hz,并指出漏磁检测不能采用频率为 5 0 Hz交流电磁化     

可实时调整刺激参数的功能性电刺激仪的研制

基于STM32微处理器设计并实现了可实时调整刺激强度的功能性电刺激仪.通过上位机设定刺激参数值;通过数字电位器或DAC转换器控制恒压源的电压实现设定的恒流输出;通过改变H桥开关管的导通时间控制脉冲的频率和脉宽实现设定的频率和脉宽,分别进行电阻和人体实验测试.结果表明,功能性电刺激器的电流幅度、频率和脉冲宽度分别在0～50 mA, 0～100 Hz和0～1 000μs范围内连续可调.该电刺激仪可以实时调整刺激参数,为闭环FES的应用提供基础.     

磁电复合振子PbZr_(0.48)Ti_(0.52)O_3/Tb_(0.3)Dy_(0.7)Fe_(1.92)的电容型磁阻抗效应

谐振频率及阻抗匹配是压电换能器中十分重要的参数.基于压电陶瓷圆环Pb Zr_(0.48)Ti_(0.52)O_3(PZT)和磁致伸缩材料铽镝铁Tb_(0.3)Dy_(0.7)Fe_(1.92)(TDF)构成"环-环"磁电复合振子,实验研究磁场作用下,由磁电复合振子的有效介电常数变化引起的电容型磁阻抗以及磁控谐振频率偏移效应.实验结果显示,谐振频率和反谐振频率下的磁阻抗可达18%、32%;当磁场为800 m T时,谐振及反谐振频率的最大偏移量约为9 k Hz.利用复合材料的磁-力-电耦合效应,对电容型磁阻抗及磁控谐振频率偏移进行了理论分析.本研究为解决压电换能器谐振频率的漂移问题及阻抗匹配提供了实验及理论基础.     

岩石在循环加载下的力学特性

采用试验设备MTS-815岩石和混凝土试验系统,对40MPa围压作用的岩样进行了常规三轴试验和不同频率的轴向循环加载试验。施加的循环荷载频率分别为0.1Hz,1Hz和3Hz。岩样为砂岩,试样平均直径为48.9mm,高度与直径之比为2:1。试验结果表明:在相同围压作用下,频率对岩样的残余变形和破坏模式有很大影响。频率越高,破坏时的残余轴向应变越大和破坏次数越多,岩样的初始刚度越大。     

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).     

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.     

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.