溶液pH测定值校正新方法

当酸度计无斜率补偿，其仪器标度与ＰＨ玻璃电极斜率不相等时，将产生测定误差。出现了同一样品，不同实验组测定的结果不同，根据电位法测定溶液ＰＨ值原理，由电极电位和酸度计测定值，导出待测溶实际ＰＨ值准确计算式，消除了Ｓ标度≠Ｓ电极时产生的测定误差，并用实验进行了验证和样品分析。     

Nitric oxide biosynthesis, nitric oxide synthase inhibitors and arginase competition for L-arginine utilization

Nitric oxide (NO) is a recently discovered mediator produced by mammalian cells. It plays a key role in neurotransmission, control of blood pressure, and cellular defense mechanisms. Nitric oxide synthases (NOSs) catalyze the oxidation of L-arginine to NO and L-citrulline. NOSs are unique enzymes in that they possess on the same polypeptidic chain a reductase domain and an oxygenase domain closely related to cytochrome P450s. NO and superoxide formation as well as NOS stability are finely regulated by Ca²⁺/calmodulin interactions, by the cofactor tetrahydrobiopterin, and by substrate availability. Strong interactions between the L-arginine-metabolizing enzymes are clearly demonstrated by competition between NOSs and arginases for L-arginine utilization, and by potent inhibition of arginase activity by N^ω-hydroxy-L-arginine, an intermediate in the L-arginine to NO pathway.     

“米巴赫”焊机电极钢刷测试分析及研制

本文阐述了对进口冷扎薄板自动生产中“米巴赫”焊机电极钢刷的结构、原理、物理性能，材质及强度进行测试分析，为自行设计制造同类产品提供可靠的依据。     

微量样品pH测量的实现

利用电化学方法将氧化铱薄膜修饰在微电极上制备微量样品pH计，此电极体积很小，测量中只需滴3~5 μL溶液即可测出测试电极与参比电极之间的电势差，然后通过数据采集卡读取数据，将电势差信号转化为数字信号，最后用Matlab拟合输出溶液对应的pH。测量结果与商用pH计基本保持一致，此电极使用方便，灵敏度高，重现性好，而且在稀、贵样品及生物样品的分析中更显示其优越性，具有广阔的发展前景。     

Electrochemical behavior of adriamycin at a cobalt ion implantation modified electrode

With Co/GCE in 0.005 mol Tris/L/0.05 mol/L NaCl solution (pH 7.1), a sensitive reductive peak of adriamgcin (ADM) was obtained by the linear scan voltammetry. The peak potential is ?0.62 V (vs. SCE). The peak current is proportional to the concentration of ADM. The electrochemical behavior of the system was studied by the linear-sweep and cyclic voltammetry. The experiments showed that the reduction at Co/GCE is a quasi-reversible process with adsorption. According to Laviron’s theory, the electrode reaction rate constant k₀ and the electron transfer coefficient a are determined to be 2.15 s^-1 and 0.62, respectively. The composition of the surface, valence state of elements and depth distribution of elements on the surfaces of Co/GCE were determined by the X-ray photoelectron spectroscopy and Auger electron spectroscopy. The experiments showed that Co was surely implanted into the surface of GCE. The implanted Co element in the form of Co-C catalyzed the reduction of ADM.     

一种设计宽带波导电光调制器的新方法

介绍一种用于计算，设计宽带波导电光调制器的新方法，用该方法对波导电光调制器进行数值计算，得到了电光调制器电极产生的电场分布，器件的特征阻抗，并优化设计出带宽可达８．１ＧＨｚ．ｃｍ和特征阻抗为５０Σ的宽带波导电光调制器。     

铂阳极在冰晶石-氧化铝溶液中的过电压

本文采用连续脉冲技术和电位扫描法研究了铂阳极上的过电压和反应机理,实验发现,在电流密度0.078～1.5A/cm~2的范围内过电压与电流密度的关系符合Tafel方程:η=0.22+0.21lgi (Ⅴ)此结果与Thonstad所观察的结果比较一致,但与Drassbach的数据相距较远,在实验的基础上,讨论了反应的控制步骤和反应历程,认为过电压由活化极化所引起,反应按复合脱附历程进行: 上述结论由残余电动势法和电位扫描法进一步证明,在实验中还观察到在铂阳极上也可以发生阳极效应,这在文献中还未见报道,但是铂阳极上的临界电流密度相当高,当氧化铝浓度饱和时为60A/cm~2。     

BBr3的合成

在合成BBr3的方法中,元素硼溴化法是比复分解法和碳化硼溴化法容易实现的合成方法.在制备元素硼的方法中,Mg—B2O3还原法是比Na-B2O3还原法、Al—B2O3还原法和Al-硼砂还原法操作方便且产率较高的合成方法.采用聚四氟乙烯管道可以对溴和BBr3取得满意的防腐和密封效果,冰盐浴可以实现高温BBr3气体的冷凝.     

Simultaneous determination of trace rare earth elements and other elements in high purity terbium oxide (Tb4O7) by ICP-AES after HPLC separation using P507 resin

This article describes a new method for the simultaneous determination of trace rare earth elements (REEs) and non rare earth elements (NREEs) in high purity terbium oxide by ICP-AES after HPLC separation using P507 resin. The chromatographic separation of the analytes from the matrix using dilute nitric acid as mobile phase was studied. The experimental results showed that a favorable separation of trace metals (Cu and Gd) from the matrix (Tb) can easily be achieved by elution with dilute nitric acid within 25 min. The proposed method was applied to the determination of trace metals (Ca, Cu, Mg, Mn, Ni, Si, La, Ce, Pr, Nd, Sm, Eu and Gd) in high purity terbium oxide. The detection limits (DLs) for the analytes ranged from 0.4–4.0 μg· g⁻¹, and the recoveries are from 78%–105%. Foundation item: Supported by the National Science Foundation of China (No. 20007010108) and Wuhan Municipal Science & Technology Commission (No. 995004080) Biography, Wanjau Ruth (1961-), female, Ph. D. candidate, Kenyatta University, Kenya, research direction: determination of trace elements.