Structure change of 156Yb at high-spin states

High-spin states of ¹⁵⁶Yb have been studied via the ¹⁴⁴Sm(¹⁶O,4n)¹⁵⁶Yb fusion-evaporation reaction at beam energy 102~MeV. The positive-parity yrast band and negative-parity cascade have been extended up to higher-spin states, respectively. The characteristics of the negative-parity sequence above the 25^－ state may related to the excitation from the nucleon in the Z=64, N=82 core. The E-GOS curve for the positive-parity yrast sequence in ¹⁵⁶Yb indicate that this nucleus may undergo an evolution from quasivibrational to quasirotational structure with increasing angular momentum. The Cranked Woods-Saxon-Strutinsky calculations by means of Total-Routhian-Surface (TRS) methods has been made to understand this structure change.     

Lifetimes of High Spin States in an Odd-Proton Nucleus 129Cs

Lifetimes of high spin states in 129Cs axe measured using the Doppler shift attenuation method. The high spin states of 129 Cs axe populated following the fusion evaporation reaction 124 Sn（UB, 6n）129 Cs at a beam energy of 65 MeV. The reduced transition probabilities B（E2） and the transition quadrupole moments Qt in the negativeand positive-paxity bands are deduced. The experimental results indicate that the Qt values of the negative parity band are smaller than those of the positive parity bands, probably due to different γ-deformation driving effects of different proton orbitals. The Qt values exhibit a considerable increase near the band crossing region in these bands. This behavior demonstrates that nuclear shape changing results from the neutron or proton alignments. The signature splitting of the πh11/2 and πg7/2 bands shows the opposite changing trend after backbending due to the h11~2 neutron and h11/2 proton alignments, respectively.     

电感耦合等离子体-质谱法测定工业硅中的痕量硼和磷

建立电感耦合等离子体-质谱法(ICP-MS)测定工业硅中痕量B和P的分析方法.采用HF-HNO3混合酸处理样品,对仪器工作参数进行优化,以Rh为校正内标,有效克服了基体效应及多元素分子离子干扰.分析结果表明,方法的检出限为:B为2.0μg·L-1、P为8.5μg · L-1,B和P的加标回收率分别为:97.2％-103.6％、95.2 ％-102.8％,精密度分别为2.6％、3.5％.方法可准确、快速测定工业硅中痕量元素B和P.     

正交光楔激光远场焦斑测量方法

为验证正交光楔激光远场焦斑测量方法在提取光斑高频组分、扩展CCD测量动态范围和减小光束质量测量误差等诸方面的有效性,以常用的光束质量因子作为衡量新方法有效性的指标,建立离焦光斑强度分布理论模型并搭建相应的实验平台进行实验验证。验证结果表明:新方法与传统远场测量方案相比,使实验所用CCD的测量动态范围拓展了约9倍,实际光斑远离中心主核区域的大量高频旁瓣分布特征从CCD背景噪声起伏中凸显出来,光束质量因子的测量平均相对误差也有约16%的精度改善。     

全息光栅制作中光栅掩模形状随曝光量及干涉场条纹对比度的变化规律

为了在光栅制作中对光栅掩模占宽比及槽深加以控制,结合光刻胶在显影过程中的非线性特性,建立了光栅掩模槽形演化的数学模型,由此分析和模拟曝光量、条纹对比度对光栅槽形的影响。结果表明:在显影条件确定时,光栅掩模占宽比随光刻胶曝光量的增大而减小,条纹对比度减小,则不仅使光栅占宽比减小,同时也是使光栅槽深减小的主要原因,这样做的前提是预先通过实验和计算确定出一个曝光量上限Ec。该方法能够反映光栅掩模形状的演化规律,为全息光栅参数预测和工艺控制提供依据。     

用质谱技术对钾、钙同位素体系特征参数测定的初探

报道了用FinniganMAT 2 62质谱技术和同位素稀释法测定了光谱纯CaO和国际二级标准Tahiti(CaCO3)的同位素40 Ca 42 Ca比值以及后者的40 Ca含量 ,RSD分别为 0 .0 2 %和 0 .1 %。对国家钾标样的测定表明 :39K、40 K和41 K同位素丰度分别为 0 .93 2 60± 0 .0 0 1 2、0 0 0 0 1 1 2 0± 0 .0 0 0 0 1 2 9和 0 .0 672 86± 0 .0 0 0 1 2 5。其中39K含量为 0 .1 2 1 72± 0 .0 0 0 2 9,与标准值在误差范围内一致。实验测定结果为在我国开展40 K 40 Ca同位素体系的定年和环境的示踪研究打下了基础     

等离子体金属纳米结构在SERS传感及可穿戴应力传感中的应用

等离子体金属(金、银)纳米结构因其特有的理化性能,被广泛应用于表面增强拉曼散射(Surface-enhanced Raman scattering,SERS)传感及可穿戴应力传感领域.其中,SERS是一种应用贵金属纳米材料增强拉曼散射信号的检测技术,该技术灵敏度高、特异性强,已被广泛用于生物医学、环境监测、食品药品检测...     

邻氯苯甘氨酸甲酯的拆分研究

以L-(+)-酒石酸作为手性拆分剂,苯甲醛作催化剂,对外消旋的邻氯苯甘氨酸甲酯混合物进行了化学拆分。S-(+)-邻氯苯甘氨酸甲酯的拆分收率达到93%, ee 99.96%,其结构经¹H NMR和HPLC确证。使用pH电位滴定法研究了邻氯苯甘氨酸甲酯与酒石酸形成的盐的稳定性,采用X-射线单晶衍射确定了一对非对映异构体盐的立体结构,并初步推测了非对映异构体的拆分机理。用共振瑞利散射分析了两种异构体盐结构。     

桥联茂金属催化剂用于双功能催化体系制备LLDPE的研究

以四种取代基不同的桥联茂金属作为乙烯共聚催化剂 ,以Ti(OR) 4为二聚催化剂组成双功能原位聚合催化剂体系 ,在同一反应釜中 ,乙烯为唯一聚合单体 ,以阳离子助剂B(C6 F5 ) 3为唯一助催化剂 ,原位制备LLDPE .该聚合体系催化剂活性高、单体插入率高、得到的聚合物为熔点低、分子量可调的超低密聚乙烯     

An amperometric biosensor based on covalent immobilization of ascorbate oxidase on biocompatiable and low-toxic poly(thiophene-3-acetic acid) matrix

The biocompatiable and low-toxic poly（thiophene-3-acetic acid）（PTAA） matrix was successfully electrosynthesized in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate（BmimPF₆） in comparison with the electrosynthesis of PTAA matrix in acetonitrile（ACN）.Ascorbate oxidase（AO） was used as a model for the development and application of biosensor.Vitamin C（VC） biosensors were facilely fabricated by the covalent immobilization of AO molecules on PTAA matrices electrosynthesized in ACN containing tetrabutylammonium tetrafluoroborate and BmimPF₆, respectively.Electrochemical impedance spectroscopy,scanning electron microscopy and FTIR spectroscopy indicated that AO molecules were covalently immobilized on PTAA matrices.Parameters of the as-obtained biosensors such as working potential,pH and temperature have been optimized.The amperometric biosensor based on PTAA matrix electrosynthesized in BmimPF₆ exhibited wider linear range,lower detection limit,higher sensitivity and bioaffinity,and better operational and storage stability than that electrosynthesized in ACN under optimal conditions.The as-obtained biosensor based on PTAA matrix electrosynthesized in BmimPF₆ was employed for the detection of VC content in commercial juices,and the result was close to the data given by manufacturers.Excellent results indicate that the PTAA matrix electrosynthesized in ionic liquid is a promising platform for the covalent immobilization of biologically-active species and the development of biosensors.