紫外分光光度法同时测量水中NO3^—和NO2^—离子

研究了利用多波长导数－－最小二乘回归一紫外分光光度法同时测量水中ＮＯ３和Ｎ炉子了含量的方法,通过测试体系在ＰＨ＝６￣７,２００￣２１８ｎｍ的吸光度,利用多波长求导及最小二乘法计算水中ＮＯ３和ＮＯ２离子的呈,并与最大吸收峰值法及多波长线形回归法进行比较,结果表明,多波长导数－－最小二乘回归优于后两者。     

双马来酰亚胺衍生物对炭黑填充NR/ SBR并用胶硫化特性的影响

测定了含双马来酰亚胺衍生物（Ｐｅｒｋａｌｉｎｋ９００）的充炭黑ＮＲ／ＳＢＲ并用胶质量比为８０／２０时,于１４５℃×６０ｍｉｎ,１８０℃×３０ｍｉｎ的硫化曲线,考察了Ｐｅｒｋａｌｉｎｋ９００用量对混炼胶硫化特性的影响。结果表明,在试验范围内,Ｐｅｒｋａｌｉｎｋ９００的加入不改变胶料的焦烧和正硫化,但能有效地改善胶料的流动特性;可提高橡胶的抗撕裂性能,且不影响其他物理机械性能;对胶料的硫化返原性具有显著的改进效果。Ｐｅｒｋａｌｉｎｋ９００加入量以１．０份为宜。     

First-principles study of potassium-doped PC61BM for hydrogen storage

It is known that metal-doped C₆₀ molecule has suitable adsorption energy for H₂ adsorption/release around room temperature. However, the gravimetric storage capacity achieved on solid samples is too low (<1 wt%). In this work we study the hydrogen storage property of a metal-doped C₆₀ derivative, K₇PC₆₁BM, with density functional theory calculations. The complex of K₇PC₆₁BM is selected because it has been observed experimentally. The calculations are performed for an isolated K₇PC₆₁BM molecule, but the limited size of interstitial space for solid phase is taken into consideration in finding the adsorption structure. It is found that K₇PC₆₁BM can at least adsorb 31H₂ molecules (5.07 wt%) due to a compact adsorption structure. The averaged adsorption energy is 0.119 eV/H₂, indicating a desorption temperature near room temperature.     

Novel branched sulfonated poly(arylene ether)s based on carbazole derivative for proton exchange membrane

Proton exchange membrane (PEM) is a vital part of polymer electrolyte fuel cells (PEFCs). So it is of great importance to design the novel polymers for PEMs to improve the performance of PEFCs. Here two highly branched sulfonated copolymers (SBP-Cz-x) were synthesized based on a novel AB₂ monomer. For all we know, it is the first time that the 9H site of carbazole was used to prepare branched polymers. These copolymers given tough and transparent membranes by solvent casting method. SBP-Cz-x membranes exhibited excellent thermal stability and remarkable dimensional stability. Moreover, proton conductivity of SBP-Cz-x was very excellent. SBP-Cz-15 (IEC = 1.33 meq.g⁻¹) owned high proton conductivity of 42.1 mS cm⁻¹ at 80 °C. SBP-Cz-15 showed a pretty low swelling ratio of 12.7% with high water uptake (32.0%). SBP-Cz-x also owned remarkable oxidation stability. This study demonstrated that the strategy of fixing locally dense sulfonic acid groups on the branched points, which were surrounded by hydrophobic segment, could improve oxidative stability and dimensional stability efficiently.     

水溶性C60衍生物的合成和医用价值（上）

对近年来有关水溶性Ｃ６０衍生物的合成进行了系统的介绍,同时对它们在生物化学、医学、材料科学等方面的应用进行了描述。     

苯酚及其衍生物的电化学聚合及耐蚀性能

以Na_2CO_3为介质,利用电化学循环伏安法在不锈钢表面上电聚合沉积聚苯酚及聚邻苯二酚、聚邻氨基酚等聚合物膜,并采用阳极极化曲线法初步评估这些聚合物膜对不锈钢腐蚀的防护作用。试验所得聚合物膜呈棕色,均匀致密,与不锈钢基体的结合较好,在氯化钠溶液中的电化学测试表明,聚苯酚及其衍生物薄膜均能有效地提高不锈钢的耐腐蚀性。     

偏导数两种定义的差异研究

对目前高校数学教材中偏导数定义进行分析与比较,认为存在两种不等价的偏导数定义,其中一种不被普遍采用的定义更加准确和严密,其使偏导数的应用更加广泛,而另一种被普遍采用的定义则便于在建立与偏导数概念有关的一整套理论体系时对其进行叙述。建议在教学中能两者兼顾,以加深学生对概念的理解,开拓学生的视野。同时,通过对两个典型错例的分析,指出这两种定义的差异所在也是学习偏导数时容易被疏忽的地方,教学中对此应特别注意。     

二苯甲酮衍生物侧基聚硅氧烷的性能与成膜形态

用原子力显微镜AFM等仪器研究了二苯甲酮衍生物侧基聚硅氧烷(PUV S i)的性能和成膜形态。结果表明,PUV S i具有非晶态结构,可形成形态学不均一、表面粗糙的硅膜。聚硅氧烷侧链上的二苯甲酮衍生物基团及其含量可影响PUV S i的性能。当侧基质量分数从31.48%降低至12.87%,PUV S i的摩尔消光系数mξax从3.4564×105下降至1.5763×105,但聚硅氧烷相应的柔软性能增加。     

一阶导数分光光度法测定片剂中司帕沙星

建立了用一阶导数分光光度法测定司帕沙星的新方法,该方法具有操作简便、灵敏度高、选择性好等特点,用于测定司帕沙星片剂中司帕沙星的含量,结果令人满意。     

Chemoenzymatic Preparation of Enantiopure Homoadamantyl β‐Amino Acid and β‐Lactam Derivatives

Racemic cis‐10‐azatetracyclo[7.2.0.1^2,6.1^4,8]tridecan‐11‐one was prepared from homoadamant‐4‐ene by chlorosulfonyl isocyanate addition. The transformation of the β‐lactam to the corresponding β‐amino ester followed by Candida antarctica lipase A‐catalyzed enantioselective (E>>200) N‐acylation with 2,2,2‐trifluoroethyl butanoate afforded methyl (1R,4R,5S,8S)‐5‐aminotricyclo[4.3.1.1^3,8]undecane‐4‐carboxylate and the (1S,4S,5R,8R)‐butanamide with>99% ee at 50% conversion. Alternatively, transformation of the β‐lactam to the corresponding N‐hydroxymethyl‐β‐lactam and the following Pseudomonas cepacia (currently Burkholderia cepacia) lipase‐catalyzed enantioseletive O‐acylation provided the (1S,4S,6R,9R)‐alcohol (ee=87%) and the corresponding (1R,4R,6S,9S)‐butanoate (ee>99%). In the latter method, competition for the enzyme between the (1R,4R,6S,9S)‐butanoate, 2,2,2‐trifluoroethyl butanoate and the hydrolysis product, butanoic acid, tended to stop the reaction at about 45% conversion and finally gave racemization in the (1S,4S,6R,9R)‐alcohol with time.