强耦合的动力学Jahn-Teller效应理论

本文讨论了强耦合情况的、即电子的静态畸变能量大于晶格或分子振动量子能量的情况的动力学Jahn-Teller效应。我们发展了一种适用于强耦合情况的微扰方法,在其中将本征值及本征函数依照电子振动耦合系数的倒数或振动量子能量与静态畸变能量之比展开成幂级数,具体讨论了O_h点群中的Г₈态,求得了电子振动能级。区别于弱耦合情况的特点主要在于:1)虽然并不发生静态畸变,但是振动模的简并性及频谱却都发生了变化;2)如果与电子相耦合的振动模是“调谐”的,则电子及晶格振动的集体运动模将出现,这个理论能被用来解释Weinstock等人所做的关于TcF₆及ReF₆的红外光谱以及Raman光谱的实验结果。     

一种稳定的自由空间量子密钥分配实验系统

基于量子密钥分配的基本原理,采用B92方案,以单光子作为信息载体,使用极化编码,搭建了一个简单易行的实验装置,实现了自由空间传输的量子密钥分配,平均每脉冲光子数为0．1,粗码率12．7kbits／s,误码率4％左右。     

腰椎间盘纤维环膨隆症站立位动态脊髓造影的临床意义

目的:在MRI或CT检查的腰腿痛病人中,通过站立位动态脊髓造影,了解椎间盘纤维环在腰椎中立、过屈、过伸三位置下的变化,并探讨其临床意义,筛选出具有手术指征的LDH病人,决定手术方式.方法:对86例LDH患者,行站立或平卧中立、过屈、过伸脊髓造影,对比分析两组动态变化.鉴别出LDB,选择性行有限椎板减压,或保留其椎间盘.结果:脊髓造影侧位像“拿破仑帽”状影,站立三位置均明显大于平卧位,差异非常显著(P＜0.01),在动态变化中平卧位者改成由中至屈曲位时,硬膜囊受压影较站立位者明显缩小,差异非常显著(P＜0.01),站立由中至伸时,压迫影较平卧位增大,差异显著(P＜0.05).其中28例,行有限椎板切除或保留其椎间盘,效果优良.结论:站立位会使LDB加重、临床症状加重,因站立过伸位使腰椎管狭窄病人症状加重.而平卧位造影时因重力负荷减轻,(拿破仑帽)影像不明显或消失,而出现假阴性.     

Correlation between Chaotic Dynamics and Level Spacings： the Lyapunov and Dixon Dip Approaches to Highly Excited Vibration of Deuterium Cyanide

Chaotic dynamics of highly excited vibration of deuterium cyanide is explored by two independent approaches： （1） the Lyapunov analysis, based on the classical phase space for the levels, and （2） the Dixon dip analysis based on the concepts of pendulum dynamics and quantized levels. The results show that there is evident correlation between these two algorithms. We also propose that the reciprocal of energy difference between two nearby Dixon dips can be taken as a qualitative measure for the degree of dynamical chaos.     

Diverse antidepressants increase CDP-diacylglycerol production and phosphatidylinositide resynthesis in depression-relevant regions of the rat brain

Background  

Major depression is a serious mood disorder affecting millions of adults and children worldwide. While the etiopathology of depression remains obscure, antidepressant medications increase synaptic levels of monoamine neurotransmitters in brain regions associated with the disease. Monoamine transmitters activate multiple signaling cascades some of which have been investigated as potential mediators of depression or antidepressant drug action. However, the diacylglycerol arm of phosphoinositide signaling cascades has not been systematically investigated, even though downstream targets of this cascade have been implicated in depression. With the ultimate goal of uncovering the primary postsynaptic actions that may initiate cellular antidepressive signaling, we have examined the antidepressant-induced production of CDP-diacylglycerol which is both a product of diacylglycerol phosphorylation and a precursor for the synthesis of physiologically critical glycerophospholipids such as the phosphatidylinositides. For this, drug effects on [³H]cytidine-labeled CDP-diacylglycerol and [³H]inositol-labeled phosphatidylinositides were measured in response to the tricyclics desipramine and imipramine, the selective serotonin reuptake inhibitors fluoxetine and paroxetine, the atypical antidepressants maprotiline and nomifensine, and several monoamine oxidase inhibitors.     

Generation of Laser Light via Ultrasonic Four-wave Mixing

On the basis of the interaction between phonons in ionic crystals with anharmonic lattice vibration, we present a laser model on acoustic nondegenerate four-wave mixing. Two beams of highfrequency ultrasound, incident on the acoustic cavity fulfilled with the medium of ionic crystal, play the role of pumping and one of the two side-band modes of the pumping frequency as an acoustic signal mode has a strong interaction with the optical cavity mode, the coupling-out of which wiIl be the light (far-infrared) output of a laser. The problem is treated with quantum-mechanics. The theory shows that there is the threshold phenomenon as usual lasers and a so called "phase-matching" condition is derived, which should be satisfied for stability of the system.     

气相色谱法检测食品工业用大孔吸附树脂有机残留量

采用气相色谱法,建立了同时检测食品工业用大孔吸附树脂中的苯、1,2-二氯乙烷、甲苯、邻二甲苯、间二甲苯、对二甲苯、氯苯、苯乙烯、二乙烯苯、丙烯腈、甲基丙烯酸甲酯等11种有机残留物的方法。色谱柱为DB-WAX毛细柱,检测器为氢火焰离子化检测器,该方法的专属性强,在所考察的浓度范围内线性相关系数均在0.99以上,最低检出限为0.002～0.008μg/mL,样品加标回收率为72.4～104.7%,稳定性、精密度和重现性的RSD分别为1.68～5.26%、1.57～6.83%、2.91～9.62%。本方法具有简便易行、准确、稳定、快速等特点。     

Sinularia属珊瑚中嘧啶类化合物的分离与鉴定

分离和鉴定了采自中国南海硇州岛软珊瑚Sinularia Bassica样本中新的嘧啶类化合物。样本用工业酒精提取,提取物溶液经乙酸乙酯萃取后,萃取物经硅胶柱层析,以极性不断增大的溶剂体系(石油醚-乙酸乙酯、氯仿-甲醇)梯度洗脱,再经过HPLC分离,得到2,4(1H,3H)-嘧啶二酮、5-甲基-2,4(1H,3H)-嘧啶二酮、1,3-二甲基-2,4(1H,3H)-嘧啶二酮和5-甲氧基-1,3-二甲基-2,4(1H,3H)-嘧啶二酮4种新的嘧啶类化合物,其结构通过红外光谱、1HNMR和13C NMR等光谱数据分析确定。     

液相色谱-串联质谱法测定牛奶和奶粉中卡巴氧和喹乙醇代谢物的残留量

建立了牛奶和奶粉中卡巴氧代谢物喹喔啉-2-羧酸(QCA)和喹乙醇代谢物3-甲基喹喔啉-2-羧酸(MQCA)残留量的液相色谱-串联质谱测定方法。将样品经0.6%(体积分数)的甲酸溶液进行消化,用Tris缓冲溶液调节pH后,加入Protease蛋白酶进行酶解,样品溶液用0.3 mol/L HCl溶液酸化后,采用阴离子交换固相萃取柱Oasis MAX进行净化和富集。分析样品以0.1%(体积分数)的甲酸溶液-甲醇-乙腈为流动相,经Inertsil ODS-3色谱柱分离,采用负离子扫描,在LC-MS/MS多反应监测模式下进行定性及定量分析。喹口恶啉-2-羧酸和3-甲基喹口恶啉-2-羧酸的方法测定下限牛奶为0.5μg/kg,奶粉为4.0μg/kg。对牛奶在0.5~5.0μg/kg,奶粉在4.0~40.0μg/kg添加水平的平均回收率为68.2%~82.5%,RSD为3.4%~12%。     

胆固醇修饰富勒烯/γ-环糊精包结复合物的生物活性

采用Bingel-Hirsch反应合成了胆固醇修饰的富勒烯(CHL-C60), 通过核磁共振(NMR)、质谱(MS)、元素分析对CHL-C60的化学结构进行了表征. γ-环糊精(γ-CD)对甾环具有较强的包结能力, 能够与CHL-C60形成包结复合物(CHL-C60/γ-CD), 从而有效提高CHL-C60的水溶性. 紫外-可见吸收光谱和荧光光谱研究结果表明, CHL-C60能够从γ-CD的疏水空腔中解离出来, 与人血清白蛋白(HSA)及牛血清白蛋白(BSA)形成稳定的复合体, 其结合常数分别为5.73×104和7.05×104 L·moL-1. 无氧条件下, CHL-C60/γ-CD通过光诱导电子转移作用断裂pBR322质粒脱氧核糖核酸(DNA), 其效率可达60.5%.