高效液相色谱切换波长法测定油菜内源激素

采用反相高效液相色谱法(HPLC)切换波长法同时测定油菜中的内源激素赤霉素(GA3)、3-吲哚乙酸(IAA)和脱落酸(ABA),以甲醇:水:乙腈(20:60:20)为流动相,结果显示其检出限分别为GA3:0.08mg/L;IAA:0.015mg/L;ABA:0.025mg/L,比单波长检测的检出限提高了4-10倍;相对标准偏差(RSD)分别为GA3:6.3%,IAA:4.34%,ABA:7.95%.本实验采用切换波长法,显著减低了各组分的检出限,建立了一种以高灵敏度对多组分体系同时进行检测的方法.同时为快速、准确测定油菜内源激素提供了可靠方法.     

具有生物活性的有机磷化合物的研究V.α—[（取代）芳氧基乙酰氧基]烷基膦酸

通过取代苯氧乙酰氯和α－羟基烷基膦酸酯的缩合反应合成了８种标题化合物，用元素分析，红外，核磁及质谱作了表征，测定了它们的除草活性和植物生长调节活性。     

牛顿二项式史话及其启示

介绍了牛顿二项式的发现过程及其思想方法,从中可以看出其真实的过程和现在教师讲授这个公式的方法有多大的不同.由此,作者谈了三点启示,值得人们回味.     

关于多项式最大公因式的进一步探讨

在[1]中有这样一个结论，对于P[x]中任意两个多项式，f(x)、g(x)．在P[x]中存在一个最大公因式d(x),且d(x)可以表示成f(x)、g(x)的一个组合．即有P[x]中的多项式u(x)、v(x)使：     

Spin and valley half metal induced by staggered potential and magnetization in siliceneSpin and valley half metal induced by staggered potential and magnetization in siliceneSpin and valley half metal induced by staggered potential and magnetization in silicene

We investigate the electron transport in silicene with both staggered electric potential and magnetization; the latter comes from the magnetic proximity effect by depositing silicene on a magnetic insulator. It is shown that the silicene could be a spin and valley half metal under appropriate parameters when the spin-orbit interaction is considered; further, the filtered spin and valley could be controlled by modulating the staggered potential or magnetization. It is also found that in the spin-valve structure of silicene, not only can the antiparallel magnetization configuration significantly reduce the valve-structure conductance, but the reversing staggered electric potential can cause a high-performance magnetoresistance due to the spin and valley blocking effects. Our findings show that the silicene might be an ideal basis for the spin and valley filter analyzer devices.     

隐马尔可夫模型在语音识别中的应用

隐马尔可夫模型（HMM）的基本技术是语音识别中较为成功的算法，主要是它具有较强的对时间序列结构的建模能力。本首先深入浅出地介绍了HMM的基本技术和一个基于HMM的孤立词语音识别系统的构成方法，其次，基于HMM尚存有一些缺陷，造成语音识别能力较弱，为此本又进一步阐述了语音识别应用中的几种改进的HMM系统及目前的热点方法－HMM与ANN构成的混合网络。     

基于MgxZn1−xO薄膜固体装配型体声波谐振器

本文研制了一种基于磁控溅射掺镁氧化锌(Mg_xZn_(1-x)O)压电薄膜的S波段固体装配型体声波谐振器(SMR-FBAR)。相比传统的氧化锌(ZnO)薄膜,Mg_xZn_(1-x)O具有高纵波声速,高电阻率优点,而且Mg原子以替位或填隙的方式进入晶格,没有改变ZnO的铅锌矿结构。通过优化磁控溅射参数的方法,获得了c轴方向生长良好的Mg_xZn_(1-x)O薄膜,并成功制得了串联谐振频率以及并联谐振频率分别在2.416 GHz和2.456 GHz的谐振器,测得其有效机电耦合系数为4.081%,回波损耗(S11)为-23.89 d B。这种SMR机械强度高、可靠性高、尺寸小,具有可立体集成到CMOS芯片表面的优势。     

Persistent current in a magnetized Rashba ring

We theoretically study the persistent currents flowing in a Rashba quantum ring subjected to the Rashba spin-orbit interaction. By introducing uniform or nonuniform magnetization into the ring, we find that a nonzero persistent charge current circulates in the ring, which stems from the original equilibrium spin current due to the Rashba spin-orbit interaction. Because of broken time reversal symmetry, the two oppositely flowing spin-up and spin-down charge currents of the equilibrium spin current are no longer equal, and so a net persistent charge current can flow in the system. It is also found that the persistent current can be modulated by the Fermi energy, the Rashba spin-orbit interaction strength and the magnetization in the ring. Moreover, the magnetization perpendicular to the ring plane can optimize the current. The persistent current flowing in the ring is a manifestation of the nonzero equilibrium spin current existing in the ring.     

α—[2—（2,4—二氯苯氧基）丙酰氧基]烃基膦酸酯的合成与生物活性

α┐［２┐（２．４┐二氯苯氧基）丙酰氧基］烃基膦酸酯的合成与生物活性贺红武刘钊杰＊汪军（华中师范大学有机合成化学研究所武汉４３００７９）（孝感师范高等专科学校化学系孝感）关键词羟基膦酸酯，合成，生物活性，除草剂１９９７－１０－２１收稿，１９９８－０４...