高效液相色谱法同时测定双酚伪麻干混悬剂中的盐酸伪麻黄碱和氢溴酸右美沙芬

建立了可同时测定双酚伪麻干混悬剂中盐酸伪麻黄碱和氢溴酸右美沙芬含量的反相高效液相色谱方法。样品先经甲醇溶解,过滤,然后以Lichrospher C6H6化学键合硅胶为固定相、乙腈-水-H3PO4（体积比为50∶50∶0.1,pH 2.5,内含1 g/L十二烷基硫酸钠)为流动相进行色谱分离,在220 nm处定量测定。结果表明,氢溴酸右美沙芬、盐酸伪麻黄碱的质量浓度分别为1.03~206 mg/L和5~200 mg/L时,其峰面积与质量浓度的线性关系良好;批内(n=7)测定的平均相对标准偏差（RSD）分别为1.8%和1.0%,批间(n=5)测定的RSD分别为2.2%和1.5%;对双酚伪麻干混悬剂中氢溴酸右美沙芬、盐酸伪麻黄碱测定回收率分别为100.0%~101.8%和95.7%~98.7%。该法适用于双酚伪麻干混悬剂中氢溴酸右美沙芬和盐酸伪麻黄碱的质量控制及含量测定,方法准确,操作简便。     

苯并菲盘状液晶的合成、亲氟效应及分子对称性对介晶性的影响

New symmetrical and asymmetrical triphenylene-containing discotic liquid crystals with two different peripheral alkyl chains, known as sym-TP(OC6H13)3(OR)3 and asym-TP(OC6H13)3(OR)3, were synthesized. Their thermotropic liquid crystal properties were investigated through polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses. The asyrranetdcal discogens are 2,6,11-rialkoxy-3,7,10-trihexyloxytriphenylenes, with the alkyl chain carbon numbers varying from 3-10, 12, and 14, while the symmetrical compounds are 2,6,10-trialkyloxy-3,7,11-trihexyloxytriphenylene. Two fluoroalkoxy substituted triphenylene discogens, 2,6,10-td(4,4,4-trifluorobutoxy)-3,7,11-trihexyloxytriphenylene and its asymmetrical isomer 2,6,11-tri(4,4,4-trifluorobutoxy)-3,7,10-trihexyloxytdphenylene were prepared. These two compounds show higher melting and clearing points than their alkoxy analogs, which implies that fluorophilic effect exists in the formation and stabilization of discotic columnar mesophase. The triphenylene derivatives TP(OC6H13)3(OR)3 with two different peripheral chains, symmetrically or asymmetrically attached on triphenylene cores, have lower melting points and clearing points than those of the higher symmetrical compounds TP(OR)6 with the same total chain carbon numbers. The mixed-chain-triphenylenes with longer alkoxy chains (n=9,10,12,14) show columnarmesophase at room temperature.     

磁电弹复合材料和刚性导电导磁圆柱压头的二维微动接触分析

论文求解平面应变状态下磁电弹复合材料半平面和刚性导电导磁圆柱压头的二维微动接触问题.假设压头具有良好的导电导磁性,且表面电势和磁势是常数.微动接触依赖载荷的加载历史,所以首先求解单独的法向加载问题,然后在法向加载问题的基础上求解循环变化的切向加载问题.整个接触区可以分为内部的中心粘着区和两个外部的滑移区,其中滑移区满足Coulomb摩擦法则.利用Fourier积分变换,磁电弹半平面的微动接触问题将简化为耦合的Cauchy奇异积分方程组,然后数值离散为线性代数方程组,利用迭代法求解未知的粘着/滑移区尺寸、电荷分布、磁感应强度、法向接触压力和切向接触力.数值算例给出了摩擦系数、总电荷和总磁感应强度对各加载阶段的表面接触应力、电位移和磁感应强度的影响.     

悬链线竖向集中力作用下的构形分析和张力计算

目前,悬链线在竖向集中力和均布荷载共同作用下的构形分析和受力计算的理论仍不完善。针对这一问题,通过引入悬链线的几何约束方程、力平衡方程和超越方程,建立了竖向集中力与均布荷载共同作用下的非线性方程组。采用牛顿迭代法求解方程组,得到了悬链线的构形和受力情况。为了验证理论计算的正确性,进行了算例和试验验证。结果表明,算例的计算结果与文献结论保持一致,试验测得的构形和水平张力大小与理论计算的构形和水平张力大小吻合较好。本文的理论计算可以更加简单精确地计算出悬链线在竖向集中力和均布荷载共同作用下的构形和受力情况,为实际工程提供重要的理论指导。     

平面波输入下海水-海床-结构动力相互作用分析

海洋工程结构的地震反应分析是保证海洋工程结构地震安全的重要环节.由于其所处的复杂环境, 该问题涉及到流固耦合和土-结相互作用.本文基于海水、饱和海床、基岩流固耦合统一计算框架,采用Davidenkov模型和修正的Masing准则考虑饱和海床的非线性,在脉冲SV波垂直入射下, 进行了海域场地和海洋工程结构的动力响应分析. 首先,对比分析了线性自由场和非线性自由场输入情形的海域场地非线性反应,结果表明线性自由场输入时反应不合理,自由场分析和场地分析应该采用相一致的本构模型. 然后,对比分析了海床分别为线性和非线性情形时,海域场地以及海水-海床-结构体系的反应特征. 与线性海床情形相比,非线性对海床反应的影响主要由如下两方面因素控制: 一方面,非线性导致饱和海床模量减小, 饱和海床与基岩间的波阻抗比减小,由基岩到饱和海床间的反射系数和透射系数增加, 导致反应增大; 另一方面,非线性导致阻尼加大, 使海床反应减小. 对于本文算例而言,阻尼对非线性海床结果的影响占主导作用.      

隔水管弯曲对钻柱振动影响的计算与分析

海洋油气资源钻探中隔水管的弯曲对钻柱振动以及钻进特性有特别的影响。为得到隔水管弯曲对钻柱振动的影响规律,对南海已钻深水井使用非线性有限元软件建立全井钻井数值计算模型,研究获得了不同垂深时隔水管弯曲对钻柱振动特性的影响规律。研究表明:隔水管弯曲会加剧钻柱的振动,钻柱振动加剧会导致钻井能耗上升、钻头切削能力下降并且会加快钻柱疲劳;当隔水管的弯曲达到某临界值,钻柱与隔水管间的接触力会陡增;井口的钩载越大,隔水管弯曲带来的井口钩载波动量越大;井越深,隔水管弯曲对全井钻柱最大弯矩和钻头切削能力的影响越小。     

Organic light‐emitting device dark spot growth behavior analysis by diffusion reaction theory

Dark spot growth rate tracing experiments performed on an organic light‐emitting device show that moisture entering into the device is relatively properly fitted by Fick's diffusion equation in the substrate/indium tin oxide (ITO)/hole transport layer (HTL)/silver (Ag) structure. It is believed that the moisture is dissolved into the polymer layer, which results in a decrease in the diffusion coefficient in the device with the substrate/ITO/HTL/electroluminescent (EL) polymer/Ag structure. The diffusion and chemical reaction occurring in the cathode layer further decreases the diffusion coefficient in the device with the substrate/ITO/HTL/EL polymer/calcium/Ag structure. Useful parameters, such as diffusion and solubility constants, describing possible mechanisms happening during dark spot growth on organic light‐emitting diode devices are extracted. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1697–1703, 2001     

Pd OECC薄膜的表面增强拉曼散射

利用较高检测灵敏度的 SERS技术 ,对浓度较低的 Pd OECC吸附在银表面上的薄层在室温下进行了拉曼谱的测量。得到 Pd OECC在强光破坏前后的 SERS光谱。在强光照射下 ,β-胡萝卜素分子的 SERS光谱的散射强度明显降低 ,且线宽增加 ,说明强光照射不但改变了β-胡萝卜素的构象 ,而且也改变了 β-胡萝卜素分子所处的微环境。其结果与强光照射前后吸收光谱的变化相一致。另外 ,没有观察到 Pd OECC薄层与银镜相互作用的其它新振动峰或Pd OECC中其它振动峰峰型的变化 ,可见 Pd OECC在银镜表面保持原来的状态 ,这证明SERS技术在光合作用光破坏机理研究中的可行性     

Longest paths and cycles in bipartite oriented graphs

In this paper we obtain two sufficient conditions, Ore type (Theorem 1) and Dirac type (Theorem 2), on the degrees of a bipartite oriented graph for ensuring the existence of long paths and cycles. These conditions are shown to be the best possible in a sense.     

Field emission behavior of cuboid zinc oxide nanorods on zinc-filled porous silicon

Single-crystalline zinc oxide (ZnO) nanorods with cuboid morphology have been prepared on the zinc-filled porous silicon substrate using a vapor phase transport method. Field-emission measurements showed that the turn-on field and threshold field of the cuboid ZnO nanorods film were about 3.2 and 8.2 V/μm respectively. From the emitter surface, a homogeneous emission image was observed with emission site density (ESD) of ∼10⁴ cm⁻². The better emission uniformity and the high ESD may be attributed to a large number of ZnO nanocrystallites as emitter on the surface of the nanorod end contributing to emission.