SYNTHESIS AND THERMAL PROPERTIES OF POLYBENZOXAZOLE FROM SOLUBLE PRECURSOR WITH HYDROXY-SUBSTITUTED POLYENAMINONITRILE

Aromatic polybenzoxazole (PBO) precursor, hydroxy-substituted polyenaminonitrile, was prepared by direct polycondensation of 1,4-bis(l-chloro-2,2-dicyanovinyl)benzene (CCB) and 4,6-diaminoresorcinol dihydrochloride (DAR) using pyridine and N,N-dimethylacetamide as condensing agent and solvent. The precursor has good solubility in polar aprotic solvent which is due to the strong dipolar nature of the main chain. The soluble precursor was subjected to thermal cyclization in an inert atmosphere to convert it into the corresponding PBO, which has its 5% weight loss temperature at 540℃ The fully cyclized PBO were characterized by FT-IR and TGA. The introduction of 10% mol 1,3,5-benzenetricarboxylic chloride (BTC) into the main chain not only has little effect on the solubility of PBO precursor but also raises its 5% weight loss temperature to 552℃ and char yield at 700℃ for the cyclized PBO with BTC.     

An Investigation on the Effect of Arsenic Poisoning on Humans,Agriculture, and Fisheries

The purpose of this investigation is to try and understand the degree of arsenic poisoning in the waste water from agricultural chemical factories which release effluents into the waterways in their vicinity. The method of determination is to use the water samples, soil, fish, clams, shell-fish, etc. found in the areas along the canals and aqueducts and those which lie upstream, midstream, and downstream and also the hair samples of people living in the contiguous areas, to check for the levels of arsenic in them by emission spectroscopy. From the analysis during a one year investigation, we find that the level of As in the water creatures of Chungkang Stream and Lu-Er-Men Stream is much higher than in the other water areas of Taiwan such as along beaches and the other rivers; the levels in the hair of the people who live nearby these water courses have a certain degree of correspondence with their eating habits and the quantity of food eaten; however, even those people who eat relatively little have almost 3% As, beyond the 2 mg/kg limit allowed for human beings. We are fully aware of the high level of food contamination on Taiwan, and this fact has been taken into consideration. The effect of As contamination in the soil on agricultural produce does not seem to have any apparent relationship. By the way, the influence of the monthly average rainfall on As contamination in the soil is not obvious.     

An example of applications of the elementary catastrophe theory in Hamiltonian systems

The convection in atmosphere discussed in ref. [1] is rigorously treated by considering the variation of environmental temperature with the height. This represents an example of applications of the elementary catastrophe theory in Hamiltonian systems.     

金属盐对O2/CO2煤粉混燃钙基脱硫反应的影响

利用添加剂调制改性的方法，考察了以碳酸钠为代表的金属盐对石灰石微观结构的影响，得出调制改性优化了石灰石的物理结构，并在离子比γ为15∶1的加入量效果最佳。在此基础上，借助定硫仪比较了O2-CO2气氛下调制前后石灰石对燃煤SO2释放的影响，并对燃烧产物进行灰熔点分析及灰成分的XRD测试。实验结果表明，在不影响煤粉燃烧结渣特性的前提下，改性后的石灰石可以更有效地抑制SO2的排放，固硫效果在1 000 ℃时达到最佳。     

Investigation of anthropic effects connected with metal ions concentration, organic matter and grain size in Bormida river sediments

An investigation on the sediment composition and grain size was carried out along the Bormida river (Piedmont, Northern Italy). The samples were taken both in the riverbed and on its banks. Multivariate statistical exploratory methods permitted to identify possible sources of primary pollution. In particular, principal component analysis (PCA) showed that there are probably at least three anthropogenic main causes of pollution, one connected with Cr, Ni and Sn, the second with cadmium and the last one with mercury. Some correlations were found between heavy metal ion concentrations and organic matter and/or the sediment grain size. Differences between the samples collected in the riverbed and on the banks were identified and the relationships between the principal components and the distance of the samples from the riverbed and from the hot spot represented by the ACNA industrial site were also analyzed.     

Black fungus derived aerogel with double faced properties

Black fungus aerogel (BFA) exhibited interesting double-faced properties. Weexplored the diverse properties of each side of the black fungus in three aspects:water contact angle measurements, liquid selective absorption capacity and air pollutant adsorption abilities.     

巢湖主要入湖河道磷的污染现状

为了解巢湖主要入湖河道中总磷的污染状况,进行了为期三年每月一次的污染调查,十五里河、南淝河、双桥河,污染较重,超出了(GH281-1999)《地表水环境质量标准》的V娄标准。污染主要来自工业废水、生活污水、和农业面源。认为只有开展农业面源污染治理,城市环境综合整治,城市环境综合整治,加强和削减农业化肥的使用量,使得入湖河道水质变好,巢湖的富营养化才能得到控制。     

Acetylenic/cyanoacetylenic complexes: simulation of the Titan’s atmosphere chemistry

The structures and energies of the 1:1 acetylene/cyanoacetylene, acetylene/dicyanoacetylene and cyanoacetylene/dicyanoacetylene complexes in solid argon matrices have been investigated using FT-IR spectroscopy and ab initio calculations, at the B3LYP/6-31G** level of theory. For the three complexes, predicted frequency shifts for the L shaped structures, characterized by a hydrogen bond between the nitrogen of the cyano group and the acetylenic proton, were found to be in good agreement with those experimental. Only in the case of acetylene/cyanoacetylene complex, we obtained a second minimum with a T shaped structure characterized by an interaction between the proton of cyanoacetylene and the Π system of acetylene. It appears clearly that HC₃N acts as an electrophile or as a nucleophile in these complexes.     

Analysis of heavy organic pollutants of confined atmospheres

Summary An improved procedure for the determination of the less volatile air pollutants of recycled closed atmospheres by activated carbon-Soxhlet extraction is proposed. After total treatment of desorbate, PAH determination is then accomplished by RP-HPLC using both adsorptiometric and fluorimetric UV detection; phenolic compounds are determined by GC-MS.This technique is suitable for very low levels of PAH and phenolic compounds.     

氧气氛中紫外光辐照官能化HDPE的结构与性能研究

采用FT－IR，XPS，WAXD，DXC，凝胶和表面自由能力分析，研究了氧化氛中紫外辐照官能化高密度聚乙烯（HDPE）的化学结构、晶体结构和表面自由能的变化。与空气相比，在氧气氛中紫外辐照HDPE能提高C－O，C（＝O）O和C＝O等含氧基团的引入速度，同时又能降低HDPE中的凝胶含量，在空气和氧气氛中紫外辐照后，HDPE的晶型没有发生变化，仍为正交晶系；HDPE的晶胞参数a,b,c以及（110），（200），（020），（011），（111）等晶面间距基本保持不变；HDPE的熔融温度下降，但熔融热焓升高，结晶度增大，表面自由能增大，且在氧气氛中辐照HDPE的变化幅度较大。