STRUCTURE-PROPERTY RELATIONSHIP BETWEEN HALF-WAVE POTENTIALS OF ORGANIC-COMPOUNDS AND THEIR TOPOLOGY

A significant correlation was found between half-wave potentials of organic compounds and their topological indices, A(x1), A(x2), and A(x3). The simplicity of calculation of the index from the connectivity in the molecular skeleton, together with the significant correlation, indicates its practical value. Good results have been obtained by using them to predict the half-wave potentials of some organic compounds.

含环氧端基酚酞聚芳醚酮E-PEK的合成及表征

由酚酞和4,4′-二氯二苯酮经亲核缩聚制得了一系列不同分子量的含—OK端基的聚醚酮低聚物,将其与环氧氯丙烷反应得到了分子量为1000～8000的含环氧端基聚芳醚酮(E-PEK)。用IR和~1H NMR表征了E-PEK的分子链结构,测定了T_g、溶解性和熔融粘度。研究了E-PEK/DDE体系的固化,固化后树脂的T_(g∞)=183～215℃,与低聚物的初始分子量有关。

STUDIES ON ORGANOLANTHANIDE COMPLEXES .40. SYNTHESIS AND X-RAY STRUCTURE OF BIS (2-METHOXYETHYLCYCLOPENTADIENYL) YTTRIUM AND YTTERBIUM TETRAHYDROBORATES

New bis (2-methoxyethylcyclopentadienyl) yttrium and ytterbium tetrahydroborates (Ln = Y, 1; Yb, 2) have been synthesized in good yield by the reaction of bis (2-methoxyethylcyclopentadienyl) lanthanide chlorides (Ln = Y, Yb) with sodium borohydride in THF at room temperature. The title complexes were characterized by elemental analyses, MS, H-1 NMR and IR spectra. The crystal structures of 1 and 2 have been determined by X-ray diffraction. 1 crystallizes from THF-n-Hexane in space group Pna2(1) with unit cell parametert: a = 1.2390(3), b = 1.1339(2), c = 1.1919 (2) nm and V = 1.6745(6) nm3 with z = 4 for D(c) = 1.39 g.cm-3.The structure was solved by direct method and refined to final R = 0.061 (for 1730 observed reflections). The Space group of 2 is Pna2(1) with unit cell parameters: a = 1.2399(6), b = 1.1371(5), c = 1.1897(2) nm and V = 1.6773(1) nm3 with z = 4 for D(c) = 1.72 g.cm-3, R = 0.038 (for 2157 observed reflections). The X ray structures and IR reveal the bidentate yttrium and ytterbium tetrahydroborate complexes with the intramolecular coordination bonds between lanthanide metal and ligand oxygen atoms.

LB膜与表面增强拉曼光谱

本文介绍了LB膜分子结构、分子取向研究的表面增强拉曼散射(SERS)方法及SERS增强机理研究中LB技术的应用。

分光光度法测定混合稀土氧化物中的镧铈合量

为解决以重稀土为主的稀土矿中少量镧铈合量的测定问题,本文提出了以Zn-EDTA和EDTA联合掩蔽La、Ce以外的大量轻、重稀土并以对乙酰基偶氮胂为显色剂测定了龙南混合稀土氧化物中少量La和Ce合量,结果令人满意。

五磷酸钆晶体中Sm~(3+)的光谱

本文研究了 GdP_5O0_(14):Sm~(3+)(GdPP:Sin)晶体的激发光谱和荧光光谱。Sm~(3+)离子的4~G_5/2→~6H_7/2跃迁的荧光发射(594nm)很强,荧光强度是 Sm~(3+)离子浓度的函数。Sm~(3+)—Sm~(3+)离子间有较严重的浓度猝灭现象。讨论了 Gd~(3+)—Sm~(3+)和 Sm~(3+)—Sm~(3+)离子间的能量传移与猝灭。给出了 GdPP 晶体中 Sm~(3+)离子的能级图。

辐射交联含乙烯基聚甲基硅氧烷与聚乙烯的合金膜

研究了含乙烯基聚二甲基硅氧烷与高压聚乙烯的合金膜(简称PDMVSPEM)的制膜、辐射剂量和材料配比等对PDMVSPVSPEM的氧氮透过选择性、力学性能和表面特性的影响,初步讨论了结构与性能的关系。只要满足温度条件,易用机械共混获得组份分布均匀的合金膜。膜的辐照效应与剂量的关系表现为剂量<0.04兆戈瑞时,产生交联;>O.04～0.08兆戈瑞,交联与裂构同时均匀进行;>0.08兆戈瑞,裂构占主导。在上述辐照剂量范围内,PDMVSPEM的P_(O_2)和α_((O_2)/N_2)未见改变;随PE含量增加,膜的P_(O_2)。呈非对称S形变化,拉伸模量E较拉伸强度δ增长快,断裂伸长ε沿U字形变化。谷底在PE含量40～50％,此刻形态结构处于相逆转阶段,并对应于膜凝胶生成量的低点。PDMVSPEM的相区尺寸很小,仅当PE含量>70％时,SEM图中方可现察到较明显的相分离结构,在PDMVSPEM的最表面层(约 5nm)产生有机硅链段的富集。即使PE含量高达90％,膜的表面特征仍与纯聚甲基硅胶的颇为相近。

铒离子选择电极的研制

在功能高分子稀土电极研制的基础上改进活性材料制备过程,成功的试制了新型的铒电极,其线性范围1×10~(-1)M～1×l10~(-5)M,检测下限达1×10~(-5)M,在室温下斜率为59mV,内忸小于200kΩ,性能稳定,寿命在6个月以上,并能在有缓冲液存在下测量稀土。

The effects of spring-neap tide on the phytoplankton community development in the Jiaozhou Bay, China

The development of the phytoplankton community was studied in the Jiaozhou Bay during the spring to neap tide in August 2001, through three cruises and a 15 d continuous observation. This investigation indicates that diatom cell abundance increased sharply following the end of a spring tide, from 9 cells/cm(3) to a peak of 94 cells/cm(3). The dominant species composition and abundance show a quick species sequence from spring to neap tide, and the dominant species at the start phase is Skeletomena costatum, then changes to Chaetoceros curvisetus, finally it changes to Eucampia zodiacus. Silicate concentration increases during spring tide, as a result of nutrient replenishment from the water-sediment interface, its initial average concentration in neap tide is 1.39 mumol/dm(3) and reached the peak average concentration of 8.40 mumol/dm(3) in spring tide. But the nitrogen concentration dropped due to dilution by the low nitrogen seawater from the Huanghai Sea, its initial average concentration in neap tide is 67 mumol/dm(3) and decreased to the average concentration of 54 mumol/dm(3) in spring tide. The degree of silicon limitation was decreased and phytoplankton, especially diatoms, responds immediately after nutrient replenishment in the water column. Skeletonmea costatum, as one of the dominant species in the Jiaozhou Bay, shows a quicker response to nutrient availability than Eucampia zodiacus and Chaetoceros curvisetus. It is proposed that dominant species composition and water column stability synchronously determine the development of phytoplankton summer blooms in the Raozhou bay.

种植密度对莜麦产量及其构成因素的影响

为给莜麦新品种（系）的推广种植提供依据，研究了种植密度对6个引进莜麦品种的产量及其构成因素的影响。结果表明，品种、种植密度及二者的互作对莜麦产量影响均不显著，但品种对穗粒数和千粒重影响极显著，种植密度及其与品种的互作对穗数和穗粒数影响显著或极显著。增加密度有降低产量的趋势。其中，8711-12-1-58、989D-11和坝莜1号的产量受种植密度的影响相对较大，而坝莜6号的产量受种植密度的影响相对较小。它们的适宜种植密度，8711—12-1-58为600万粒／ha，989D-11、坝莜1号和坝莜6号为375万粒／ha。

复合不育剂对高原鼠兔种群控制作用的研究

通过室内试验选定致高原鼠兔雌性和雄性不育或抗生育作用且对环境低污染或无污染的不育剂各一种。雌性不育剂的半致死剂量LD50为8.68mg／kg，半不膏剂量ED50为2．11mg／kg。雄性不育剂的半致死剂量LD50为121.42mg／kg，半不育剂量ED50为43.70mg／kg。前者的主要作用特点是导致子宫内膜出血，体重下降，从而引起胚胎流产或吸收，而后者的作用部分是睾丸，对曲细植小管内精子、精子细胞、精母细胞以及管壁都有不同程度的损坏。高原鼠兔对两种不育剂配置的复合不育剂毒饵的摄食系数为0.33。采用复合不育剂毒饵在野外建立不育种群，结果表明，实验区不育种群密度由原来的56只/hm2降至8只/hm2，而对照区种群密度则由原来的54只/hm2增至138 hm2。实验区不育种群因胚胎流产和吸收，产仔率明显低于对照区。

石生苔藓氮含量和氮同位素指示贵阳地区大气氮沉降的空间变化和来源

对贵阳市区到农村地区4个方向的石生苔藓氮含量和氮同位素组成进行了对比分析.苔藓氮含量变化范围为0.85%-2.97%,并从市区（2.24%±0.32%）往外明显降低（1.27%±0.13%）,表明贵阳市区氮沉降最高、往外逐渐降低,但在较远的农村地区（〉25 km）苔藓氮含量出现回升（平均1.33%-1.75%）,反映了农村地区大气氮输入有所增加.苔藓氮同位素均为负值（-12.50‰--1.39‰）,并从市区到农村地区明显升高.市区苔藓较负的氮同位素比值（平均-8.87‰--8.59‰）主要指示了城市排泄物和污水所释放的氨源贡献,而郊区和农村地区苔藓较高的氮同位素信号（平均-3.83‰--2.48‰）主要反映了农业氨源的影响,苔藓氮含量回升可能与农业活动增强有关.此外,贵阳地区苔藓氮同位素的分布特征与受氧化态氮源控制的地区苔藓氮同位素变化相反,因而,贵阳地区大气氮沉降以铵（NHx）沉降为主,该结论有助于更加准确地认识城市地区大气氮沉降的来源和变化.