8—氮鸟嘌呤的极谱伏安行为

用循环伏安法（ＣＶ）、电流采样极诸法（ＳＣＰ，即ＴＡＳＴ）、常规脉冲极谱法（ＮＰＰ）、微分脉冲极谱法（ＤＰＰ）、线性扫描伏安法（ＬＳＶ）、Ｏｓｔｅｒｙｏｕｎｇ方波伏安法（ＯＳＷＶ）和计时库仑法（ＣＣ）等电化学技术研究了抗癌药物８－氮鸟嘌呤（８－ａｚａｇｕａｎｉｎｅ，ｇｕａｎａｚｏｌｏ，简称８－ＡＧ）的极谱伏安行为．在 ０． １ｍｏｌ／Ｌ Ｈ２ＳＯ４底液中，８－ＡＧ有一良好的还原峰，峰电位（Ｅｐ）在－０． ９５Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ，下同）附近，８－ＡＧ浓度在４×１０－６～８×１０－４ｍｏｌ／Ｌ范围内．峰高与浓度有良好的线性关系，线性相关系数ｒ＝０．９９９９～０．９９１０，检出限为１× １０－６ｍｏｌ／Ｌ．实验证明了该峰具有吸附性．本文提出了电极反应机理，它包括：酸性介质中８－ＡＧ的质子化、质子化的８－ＡＧ在汞电极上吸附以及完全不可逆的两电子还原过程．同时用量子化学计算方法（全略微分重叠法即ＣＮＤＯ／２）对８－ＡＧ和鸟嘌呤的各原子的净电荷以及Ｗｉｂｅｒｇ键级进行了计算，从理论上解释了８－ＡＧ的电化学还原机理。     

微量热法表征邻香草醛氨基葡萄糖Schiff碱锌配合物的抗菌活性

用微量热法测定了大肠杆菌（细菌）及其在Ｚｎ－ｏ－ＶＧ（ｏ－ＶＧ：邻香草醛氨基葡萄糖Ｓｃｈｉｆｆ碱）作用下不同温度下的热谱；计算了它的生长速率常数ｋ、传找时间Ｇ、抑制率Ｉ、总产热量Ｑ、单个细菌的平均产热Ｑ０的单位时间平均每个细菌的产热量＾－量Ｑ０；建立了细菌生长代谢各种参量之间的函数关系，探讨了在不同温度和药物作用下细菌的生长代谢；发现可用ｔｇ、ｔｒ和ｔ表征细菌的生长代谢和药物的抗菌活性。     

全光谱技术同时测定混合物中对—硝基苯酚,邻—硝基苯酚和2,4—二硝基苯酚

采用了两种全光谱技术（付立叶主组分回归和目标转换因子分析）研究混合物中对硝基苯酚、邻硝基苯 酚和２，４－二硝基苯酚的同时测定。编制了名为ＳＰＧＦＰＧＲ和ＳＰＧＲＴＴＦＡ的两个程序进行计算。８个误差函数用 以推断因子数目，实验结果显示这两种方法是成功的。     

电位分析多次标准加入法的新算法

195 2年Ｇｒａｎ提出用图解法确定电位滴定终点 ,并成功地应用于电位滴定和电位分析多次标准加入法中 ,但该法必须事先知道电极斜率 ,或采用空白实验校正斜率。随后许多学者纷纷提出各种算法以弥补其不足 ,如Ｔａｙｌｏｒ级数法[1] 、单纯形调优法[2 ] 等等 ,但由于算法复杂而难以推广。我们发现如将两种较简单的数学方法即迭代法和一元线性回归法结合一体 ,可简便、快速、准确地计算出待测试液浓度 ,并同时得到电极斜率及截距。1　基本原理　　设待测试液浓度为ｃｘ,测得电位为Ｅｘ,由Ｎｅｒｎｓｔ方程知 :　　　　Ｅｘ=Ｅ +ｓｌｇｃｘ (…     

四价锗与3，4－二羟墓苯甲醛配合物的极谱研究

本文采用极谱法研究了Ｇｅ（Ⅳ）－３，４－二羟基苯甲醛（ＤＨＢ）配合物的组成，条件稳定常数．并对该配合物的极谱波性质进行了研究．     

化学反应动力学研究法

由完全非线性函数ｆ（ｔ）＝Ａ＋Ｂｅ＾－ｋ１ｔ＋Ｃｅ＾－ｋ２ｔ经变换得到自函数递推方程，根据回归分析理论，建立了一种化学反应动力学研究法－－自函数回归法，应用该法在２５℃水溶液中研究了乙酸乙酯和丁酸乙酯的皂化反应的动力学常数。     

用作工人玻璃体的聚乙烯基吡咯烷酮水凝胶的流变性

合成了交联的聚乙烷基吡咯烷酮水凝胶,考察了凝胶在注射前和经ＷＮ１２号针（直径１．１８ｍｍ）注射后的粘弹性。注射前,所有试样表现出交联网络的特征,即Ｇ′〉Ｇ″且对ω的斜率接近零,并且随交联剂用量降低,储存模量和回弹性减小。注射后,部分试样模量急剧减小;未加交联剂的试样粘弹性保持不变,仅有样品Ｂ８注射后网络结构破坏较小,粘弹性变化很小且保持了注射前良好的回弹性,比其他各样品更适宜用作工人玻璃体。     

白色体系化学计量学方法研究-MLR、Kalman滤波法、PCR、PLS和褶合光谱法的比较

对白色体系的化学计量学方法进行了研究,着重比较了多元线性回归法（MLR、Kalman滤波法（KF）、主成分回归法（PCR）、偏最小二乘法（PLS）和褶合光谱法等方法的原理,并用上述方法进行复方磺胺甲E唑片剂的不分离分析,表明间接校正法（PCR、PLS等）比直接校正法（MLR、KF等）得出的结果更准确。而以既包容了导数光谱法和正交函数法、又与PLS相结合的褶合光谱法结果最好。     

小波潜变量回归和广义回归神经网络同时测定三组分混合物

本文采用小波潜变量回归（WLVR）方法，同时测定重叠的光谱信号。结合小波阈值法和主组分分析（PCA）改进除噪质量。八个误差判据用于推断因子数目。潜变量由小波处理过的信号投影到正交基矢量而获得。广义回归神经网络（GRNN）被应用于多组分同时测定。依据算法原理编制了三个程序（PWMRA、PWLVR和PGRNN）执行有关计算。三个方法（WLVR、LVR（潜变量回归）和GRNN）同时测定三组分混合物，获得满意的结果。     

用四种离散变换主组分回归方法分辨重叠吸收光谱

将离散小波变换、小波包变换、傅里叶变换和离散余弦变换与主组分回归方法结合构成4种离散变换主组分回归方法,编制了离散变换主组分回归方法的计算程序。将离散变换主组分回归方法用于处理对硝基甲苯、对硝基酚和对硝基苯胺混合物的重叠紫外吸收光谱数据。结果表明,离散变换主组分回归方法优于主组分回归方法,试样质量浓度的预测值与实际值的相对预测标准误差由3.81%降至约1.11%。     

Measurements of relaxation time of a polyethylene melt

A device for measuring the elasticity of polymer melts has been designed by one of us (B. Maxwell). The device was used to obtain the relaxation modulus in shear of a linear polyethylene melt. From these data a discrete relaxation spectrum was derived. The range of the obtained spectrum was confirmed to correspond to the terminal zone of the “entanglement plateau” of the spectrum. The limiting dynamic viscosity (as frequency approaches zero) was obtained by integrating the relaxation modulus with respect to time. The viscosity and its activation energy were found to agree closely with the flow viscosity and the flow activation energy, respectively, involved in capillary flow.     

Melt rheology of polypropylene containing small amounts of high molecular weight chain. I. Shear flow

Large enhancements of the melt strength of polypropylene (PP) were achieved by the introduction of high molecular weight polyethylene (PE) into PP. The viscoelastic properties of the high‐melt‐strength PP melts under shear flow were investigated. It was found that the rheological properties of the high‐melt‐strength PP were distinctly different from those of conventional PP. The elastic response at low frequencies was significantly enhanced in comparison with the conventional PP, implying a presence of a long relaxation time mode that was not revealed in conventional PP. In step‐shear measurements, the fast and slow relaxation processes that characterized the linear viscoelastic properties were observed also for nonlinear relaxation moduli. The dependence of the damping for the slow process of the high‐melt‐strength PP on shear strain was much weaker than that of the fast process. These rheological behaviors characterizing the long relaxation time mode were further enhanced with the increasing concentration of high molecular mass PE. The unusual shear rheological behaviors were discussed in view of the role of high molecular weight PE as a long relaxation time mode within PP. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2692–2704, 2001     

Influence of the Phase Morphology on the Viscoelastic Behaviour of Polymer Blends (PP-EPR)

Summary. Melts of polyethylene-propylene-rubber (EPR, blends of linear polyethylene, linear polypropylene, and PE-PP copolymer) show phase separation. The influence of the phase morphology on the viscoelastic behaviour is studied with the aid of the dynamical moduli. The measured moduli of the fraction of the linear homopolymer of an EPR agree with the moduli calculated from the molar mass distribution of this fraction. In contrast, the copolymer fraction shows a strong rubber-like behaviour (represented by a characteristic relaxation time spectrum). Mixtures of 80 wt% linear PP and of EPRs with low copolymer content are not rubber-like liquids. In addition, the moduli from them can be calculated from the moduli of the components with the aid of Palierne’s emulsion model. This clearly reveals that the linear PP forms the matrix in this case. Mixtures of 80 wt% linear PP and of EPRs with high copolymer content show rubber-like behaviour and Palierne’s emulsion model is not applicable on them. Obviously, the copolymer fraction forms a physical network.     

Characterization of elongation viscosity for polyethylene melts

Elongation viscosity is an important characterization of flow properties for polymer melts. In the present article, a new extensional viscosity equation for polymer melts was established by introducing a relaxation time equation based on the Cross model. The elongation viscosities of a low-density polyethylene (LDPE) melt at 200 °C and a metallocene linear low-density polyethylene (mLLDPE) melt at 130 °C were estimated using this equation; then, the calculations of the melt elongation viscosity were compared with the measured data from the extension experiments of the LDPE melt and the mLLDPE melt reported in the reference. Good agreement was found between the predictions and the measured data from the LDPE and mLLDPE melts. In addition, this equation is easy to use for characterization of elongation viscosity during single shaft elongation flow for polymer melts.     

Melt rheology of polylactide/montmorillonite nanocomposites

In this article, the linear and nonlinear shear rheological behaviors of polylactide (PLA)/clay (organophilic‐montmorillonite) nanocomposites (PLACNs) were investigated by an Advanced Rheology Expanded System rheometer. The nanocomposites were prepared by master batch method using a twin‐screw extruder with poly(ε‐caprolactone) (PCL) as a compatibilizer. The presence of org‐MMT leads to obvious pseudo‐solid‐like behaviors of nanocomposite melts. The behaviors caused by the formation of a “percolating network” derived from the reciprocity among the strong related sheet particles. Therefore, the storage moduli, loss moduli, and dynamic viscosities of PLACNs show a monotonic increase with MMT content. Nonterminal behaviors exists in PLACNs nanocomposites. Besides the PLACNs melts show a greater shear thinning tendency than pure PLA melt because of the preferential orientation of the MMT layers. Therefore, PLACNs have higher moduli but better processibility compared with pure PLA. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 3189–3196, 2007     

Linear viscoelastic behaviors of polybutene-1 melts with various structure parameters

The effects of weight-average molecular(Mw), molecular weight distribution(MWD), and isotacticity on the linear viscoelastic behavior of polybutene-1 melts are studied. It is observed that the linear viscoelastic region becomes slightly narrower with increasing frequency. In frequency sweeps, the transition of the polymer melts flow from Newtonian flow to power-law flow can be observed. The melts with higher Mw and/or broader MWD, as well as higher isotacticity exhibit higher complex viscosity, zero shear viscosity, viscoelasticity moduli, relaxation modulus, broader transition zone, while lower critical shear rate, non-Newtonian index, and the frequency at which elasticity begins to play an important role. The relationship of zero shear viscosity on Mw has been established, which agrees with the classical power law. Furthermore, it is found that the cross-over frequency decreases with increasing Mw and the cross-over modulus increases with narrowing MWD.     

On continuous relaxation spectrum. Method of calculation

A method of continuous relaxation spectrum calculations based on the Mellin integral transform has been proposed. It was demonstrated that the equivalent results were obtained regardless an experimental viscoelastic function used a base for calculations. It proves the correctness of the proposed method. The obtained relaxation spectrum provides right predictions in calculation of different viscoelastic functions for various polymeric materials regardless their relaxation state.     

Non-Newtonian behavior of polydisperse polymer melts as a consequence of the evolution of their relaxation spectra

The non-Newtonian flow of polydisperse polymer melts is shown to be described by a model according to which an increase in the shear rate leads to the suppression of the dissipative losses of the relaxation modes of each fraction. The higher the shear rate, the greater the suppression. The relaxation spectrum of each monodisperse fraction is represented by the Rouse distribution, and only this form of spectrum leads to a ??spurt?? effect at the critical shear stress. Hence, the physical content of the model that relates the non-Newtonian behavior of polymer melts to their molecular-mass distributions consists in the fact that the relaxation modes responsible for energy dissipation are gradually truncated from the side of high relaxation times. The higher the M of a given fraction, the greater the contribution of this part of the spectrum to the total viscous losses. In this case, the truncation of the spectrum from the side of high relaxation times is equivalent to the gradual ??elimination?? of high-molecular-mass fractions of the polydisperse polymer from the contribution to dissipation. The shear-rate-dependent evolution of the relaxation spectrum of the medium is the structural mechanism that causes the non-Newtonian flow of polymer melts. The efficiency of the proposed model is shown through calculation of the flow curves for polymers with known molecular-mass distributions. The calculation results are in agreement with the experimental data. The theoretical ideas developed with the use of the ?? function to describe molecular-mass distributions have made it possible to solve the inverse problem, i.e., to establish a quantitative relationship between the shape of the flow curve and the molecular-mass distribution and, thus, to calculate the molecular-mass distributions according to the shearrate dependence of the apparent viscosity.