Topography of acoustic response characteristics in the midbrain inferior colliculus of Kunming mouse

Topography of acoustic response characteristics of the midbrain inferior colliculus(IC)of the Kunming mouse was studied by using extracellular recording techniques.The characteristic frequency(CF)range represented in the different divisions of the IC differed markedly:4-15 kHz in the dorsal cortex(DC),10-70 kHz in the central nucleus(CN),and 4-35kHz in the external cortex(EC).The CF in the CN increased from dorsal and lateral to ventral and medial,higher CFs represented at its ventromedial part and lower CFs at its dorsal part.The isofrequency contours of CFs were incurvate.Minimum thresholds(MT)of the auditory neurons in DC and the central part of CN were lower(about 10dB SPL),but considerably higher in the dorsal and ventral region of EC.Results suggest that each of the divisions in the mouse IC may have different auditory functions.     

Observation of contrast variations of a copper (Ⅱ) complex by scanning tunneling microscopy

This report presents experimental observations of dramatic variations in STM images of bis [1,3-DI(p-n-tetradecyloxyphenyl)propane-1,3-dionato]copper( Ⅱ） (abbreviated to C14O-Cu)physisorbed on HOPG as the bias voltage is changed .Several representative image patterns were obtained for the rich changes of the internal contrast of the molecule .Submolecular features of the molecular cores and the interdigitated alkyl parts are clearly visible.     

Electrochemical hydrogen storage of aligned multiwalled carbon nanotubes

Hydrogen storage of aligned multi-walled carbon nanotubes (a-MWNTs),non-aligned MWNTs(n-MWNTs) and graphite electrodes are studied by the electro-chemical measurements .The electrodes are prepared by mixing carbon nanotubes (CNTs) copper powder and ptfe binder in a weight ratio of 1:5:3 and compressing the mixture into porous nickel collector,The results show that the electrochemical hydrogen storage capacity of the a-MWNT electrode is up to 1625 mAh/g corresponding to a high hydrogen storage of 5.7 wt% ,which is 10 times that of graphite electrode and is 13 times that of n-MWNT electrode, suggesting that a-MWNTs are promising materials for electrochemical hydrogen storage.     

Recombinant PsbF from Synechococcus sp. PCC 7002 forms β:β homodimeric cytochrome b559

All organisms with oxygenic photosynthesis contain two photosystems:photosystem Ⅰ(PSⅠ)and photo-systemⅡ(PSⅡ),The minimal photosystem Ⅱ particles which are photochemically active contain three subunits:D1,D2 and cytochrome b559 (Cyt b559),The function of Cyt b559 remains unclear,We have successfully overxpressed the psbF gene,encoding the β subunit of Cyt b559,from a marine cyanobacterium Synechoccous sp.PCC 7002 as a fusion gene and obtained a redox-active from of Cyt b559,When the N-terminal GST protein of the fusion gene product was removed with thrombin ,the PsbF protein was still redox-active,suggesting that the recombinant PsbF can form dimer in Escherichia coli.The absorption spectra of either the oxidized from or the reduced form of both GST fusion protein and the purified PsbF dimer and the difference Spectra between the two forms are the same as that of the Cyt b559 isolated from the higher plants .Redox titration analysis of recombinant PsbF showed that the mid-point redox potential of the recombinant Cyt b559 was approximately 50 mV, which is close to the low potential of Cyt b559 ,The results are helpful to the understanding of locatlization and function of Cyt b559 on thylakoid membranes.Ⅰ     

单部件可修系统的一个几何过程维修模型

本文研究了单部件、一个修理工组成的可修系统的最优更换问题,假定系统不能修复如新,以系统年龄T为策略,利用几何过程求出了最优的策略T^*,使得系统经长期运行单位时间内期望效益达到最大,并求出了系统经长期运行单位时间内期望效益的显式表达式。在一定条件下证明了T^*的唯一存在性。最后还证明了策略T^*比文献[6]中的策略T^*优。     

基于粗糙集理论的人工神经网络故障诊断系统

在故障诊断神经网络模型的基础上,以粗糙集理论中的信息系统属性值表为主要工具,将复杂的神经网络分层的简并剔除其中不必要的属性,克服了网络规模过于庞大及分类识别速度慢等缺点,取得了减少分类过程中的模式匹配搜索量的良好效果,并给出基于粗糙集理论的分层发掘神经网络模型结构及算法,结果表明该系统对工程应用具有一定的参考价值。     

Ｍ—通道分解综合系统新框架及其信号的最佳对称延拓策略

在利用小波变换进行图象压缩时,需对图象进行边界处理以减小边界误差。一个行之有效的边界处理方法是对称延拓,存在许多不同的对称延拓。笔者提出了最佳对称延拓的概念,给出了求最佳对称延拓的算法,并用该算法得出了一般的Ｍ－通道综合系统中各环节的最佳延拓和加窗方案。     

用U型管法测定液体的表面张力系数

介绍了用U型管法测定液体表面张力系数的原理和方法。由于采用线阵光电耦合器件(CCD)进行测量,提高了测量精度。     

不同烷基季铵盐对膨润土絮凝性的影响

以四乙基溴化铵((Et)4NB)、一种二价季铵盐(MD膜驱剂)、十二烷基三甲基溴化铵(DTAB)和十六烷基三甲基溴化铵(CTAB)为改性溶剂,考察改性膨润土的分散、絮凝作用和层间含水量,对膨润土用X射线衍射(XRD)、傅立叶红外(FT-IR)和分光光度计等分析表征.结果表明,烷基季铵盐已进入膨润土晶层之间,使膨润土层间含水量降低,而MD膜驱剂改性膨润土含水量最小.烷基季铵盐在高浓度下对膨润土都有一定的絮凝性,膨润土的沉降体积随季铵盐浓度增大出现一个极大值.与(Et)4NB,DTAB和CTAB相比,MD膜驱剂在较低浓度下对膨润土就有较好的絮凝性.膨润土在MD膜驱剂或DTAB溶液中沉降平衡时间较(Et)4NB或CTAB的短.     

单质铟在空气中原位热氧化合成氧化铟纳米锥

以Au作催化剂，将金属铟在空气中加热到900-1000℃，在单质铟表面制备出In2103纳米锥．纳米锥的直径随着加热时间的延长和反应温度的升高而增加．采用拉曼光谱、扫描电镜和透射电子显微镜对产物进行了表征分析．结果表明，产物为立方相单晶结构的In2O3纳米锥，其直径和高度分别在0．08～0．7μm和0、5～3．1μm范围可调，且金作为催化剂在纳米锥的生长过程中起了非常重要的作用．基于此研究结果，提出了纳米锥的可能生长机理