农药丁吡吗啉与腐殖酸作用机理探讨

探讨农药丁吡吗啉与腐殖酸的作用机理, 可进一步了解农药在土壤中腐殖酸催化下降解的行为过程。将市售腐殖酸进行逐级分离,获得黄腐酸、棕腐酸和黑腐酸的固态或溶液状态,而后分别与农药丁吡吗啉进行作用,利用红外,荧光两种分析方法对其作用机理进行了解释。结果表明,三组分与丁吡吗啉之间广泛存在范德华力、次级键等弱作用力。黄腐酸与丁吡吗啉之间存在氢键和电荷转移吸附等作用力,棕腐酸与丁吡吗啉存在电荷转移吸附等作用力,黑腐酸与丁吡吗啉之间的作用力最弱,即依照黄腐酸、棕腐酸、黑腐酸三组分平均分子量依次递增的顺序,与农药丁吡吗啉之间的作用力依次降低。     

Measurement of Gamma-Rays from 11ΛB and 12ΛC

From the ^12 C（π^＋,K^＋）^12 AC reaction the γ -rays of 261.6±0.24 ke V（7/2^＋ →5/2^＋）and 1481.7±0.7 ke V（1/2^＋ →5/2^＋） of ^11 A B,and 2667.3±2.8 keV（1^- 2 → 2^- 1）of ^12 A C hypernuclei have been identified using a large germanium detector array Hyperball2 at K6 beam line of KEK. The observed energies of the transitions 1481.7keV and 261.6 keV are significantly different from the values predicted by the shell model using the △ and SN parameters determined from the ^7 △ Li data.     

Measurement and analysis of fission rates in a spherical mockup of uranium and polyethylene

Measurements of the reaction rate distribution were carried out using two kinds of Plate Micro Fission Chamber （PMFC）. The first is a depleted uranium chamber and the second an enriched uranium chamber. The material in the depleted uranium chamber is strictly the same as the material in the uranium assembly. With the equation solution to conduct the isotope contribution correction, the fission rate of 238U and 235U were obtained from the fission rate of depleted uranium and enriched uranium. Then, the fission count of 238U and 235U in an individual uranium shell was obtained. In this work, MCNP5 and continuous energy cross sections ENDF/BV.0 were used for the analysis of fission rate distribution and fission count. The calculated results were compared with the experimental ones. The calculation of fission rate of DU and EU were found to agree with the measured ones within 10% except at the positions in polyethylene region and the two positions near the outer surface. Because the fission chamber was not considered in the calculation of the fission counts of 238U and 235U, the calculated results did not agree well with the experimental ones.     

145Er的β延发质子衰变性质研究

通过92Mo(58Ni, 2p3n)熔合蒸发反应生成了非常缺中子核145Er。利用氦喷嘴带传输系统把研究目标核传输到低本底测量站, 进行了质子 γ符合测量, 得到了不受同量异位素干扰的145Er的β延发质子谱。经过仔细分析与延发质子符合的γ谱, 发现了145Er的11/2-同核异能态具有β延发质子衰变性质。经拟合退激144Dy不同激发态γ跃迁的衰变曲线, 得出145Er的1/2+基态和11/2-同核异能态的半衰期分别为(1.6±0.6)和(0.6±0.1) s。最后, 简单介绍了中重质量区缺中子新核素的合成及衰变研究计划。The neutron deficient isotope 145Er was produced via the fusion evaporation reaction 92Mo(58Ni, 2p3n). The reaction products were transported to a low background counting area using a He jet tape transport system, and proton γ coincidence measurements were carried out. Based on the analysis of γ transitions in coincidence with β delayed protons, the β delayed proton decay of an νh11/2 isomer in 145Er was proposed. By fitting the decay curves of the γ transitions depopulating the low lying states in 144Dy, the half lives of the ground state and the νh11/2 isomeric state in 145Er were deduced to be (1.6±0.6) and (0.6±0.1) s, respectively. An experimental plan to synthesize new β delayed proton precursors in the medium heavy mass region has been presented.     

太阳的光辉

 人类处在天地之间，每日目睹昼夜更替，每年经历寒暑变迁。"日居月诸，照临下土"。人类在阳光下生活、生存，与生具备的亘古不变的好奇心，也一直激励人们关心周围的自然现象，"日月安属?列星何陈?"几千年来，人类历经世代更迭，观念更新，从以地球为中心的地心说到以太阳为中心的日心说，直至1609年伽利略开始使用望远镜观测太阳黑子，人类对太阳逐渐有了正确的科学了解。到国际天文学联合会（IAU）成立的1919年为止，人们已经发现了太阳光谱中的大量谱线（Fraunhofer，1814）；发现了太阳黑子的蝴蝶图分布及其11年活动周期（Schwabe，1843）；发现了剧烈的太阳耀斑活动（Carrington，1859）；通过日食期间的太阳光谱观测，发现了一种新元素：氦（Secchi，1868），次年又发现了一条与众不同的谱线，它与当时所有已知元素的谱线都不吻合，以为是发现了另一种新元素；此外，还发现了太阳黑子具有强磁场（Hale，1908），这是人类首次在地球以外的天体上发现磁场。这些工作为太阳物理以及天体物理的发展奠定了重要基础。     

Model Hamiltonian for the Quantum Anomalous Hall State in Iron-Halogenide

We examine quantum anomalous Hall(QAH) insulators with intrinsic magnetism displaying quantized Hall conductance at zero magnetic fields.The spin-momentum locking of the topological edge stats promises QAH insulators with great potential in device applications in the field of spintronics.Here,we generalize Haldane’s model on the honeycomb lattice to a more realistic two-orbital case without the artificial real-space complex hopping.Instead,we introduce an intraorbital coupling,stemming directly ...     

THz波的产生及探测技术

THz技术是20世纪90年代发展起来的一门新兴学科,本文较为详细地介绍了目前产生THz波的主要方法、原理以及探测THz波的主要手段和机理.     

低温Ar基质中CF3I激光光氧化反应中间体研究

研究了１０Ｋ Ａｒ基质中ＣＦ３Ｉ与Ｏ２经２６６ｎｍ脉冲激光辐照的光氧化反应，利用低温基质隔离技术和付里叶变换红外光谱法检测反应过程中产生的中间体有ＣＦ３ＯＯＩ、ＣＦ３ＯＯ、ＣＦ３Ｏ和ＣＦ３ＯＩ。通过量子化学从头算，对ＣＦ３ＯＯＩ的结构和振动频率进行计算，并对观察到的３个吸收峰进行了归属，首次确证ＣＦ３ＯＯＩ为新的中间体，根据ＣＦ３ＯＯ、ＣＦ３ＯＯＩ、ＣＦ３Ｏ、ＣＦ３ＯＩ随光照时间的生长和衰减，提出     

通过减小碰撞导致的退相干和谱线增宽提高光晶格钟稳定度

在⁸⁷Sr空间光晶格钟原理样机上实验观测了原子碰撞对谱线激发率抑制以及对谱线的展宽,并观测到由非弹性碰撞导致的原子损耗。通过简单地将原子数从6000减小至2000,实现了线宽为1.9 Hz的钟跃迁谱线,并将空间光晶格钟原理样机的稳定度提升至1×10^-15(τ/s)^-0.5。相关实验结果对研究光晶格的多体相互作用对钟跃迁谱线的影响具有重要意义。     

可调内阻电池在中学物理实验中的应用

可调内阻电池是新设计的教学用直流电源。它将解决高中物理稳恒电流实验教学中的一些难题,现介绍于下,供做参考: 一、验证闭合电路欧姆定律闭合电路欧姆定律为:I=ε/R r或ε=IR Ir=U_外 U_内实验根据后一式进行,即验证内外电路上的电势降落之和是一恒量,且等于电池的电动势。(一)、实验仪器及实验电路实验按图1或图2所示的电路进行。虚线