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991.
结合小东江污染状况与成因,系统研究了流域产污、排污、截污、纳污的平衡,并结合小试研究确定了重点工业污染企业污染治理与污染总量控制、城市排水系统截污与污水处理厂工艺技术改造、河流引水与清淤、垃圾清运等综合治理、分步实施的工程方案。经综合治理,小东江当年实现水质变清,工程治理结束后,已达到地表水Ⅲ类水质,环境综合治理达到了预期效果。 相似文献
992.
Adsorption and catalytic hydrolysis of the herbicide diethatyl-ethyl [N-chloroacetyl-N-(2,6-diethylphenyl)glycine ethyl ester] on homoionic Na+-, K+-, Ca2+-, and Mg2+-montmorillonite clays were investigated in water solution. The Freundlich adsorption coefficient, Kf, got from isotherms on clay followed the order of Na+ K+ > Mg2+ Ca2+. Analysis of FT-IR spectra of diethatyl-ethyl adsorbed on clay suggests probable bonding at the carboxyl and amide carbonyl groups of the herbicide. The rate of herbicide hydrolysis in homoionic clay suspensions followed the same order as that for adsorption, indicating that adsorption may have preceded and thus caused hydrolysis. Preliminary product identification showed that hydrolysis occurred via nucleophilic substitution at the carboxyl carbon, causing the cleavage of the ester bond and formation of diethatyl and its dechlorinated derivative, and at the amide carbon, yielding an ethyl ester derivative and its acid.These pathways also suggest that hydrolysis of diethatyl-ethyl was catalyzed by adsorption on the clay surface. 相似文献
993.
994.
在TiO2催化剂上苯酚光催化氧化反应研究2-多相光催化氧化与直接光解反应的比较 总被引:14,自引:0,他引:14
在TiO2悬浆体系,中压汞灯作用下,通过苯酚降解过程中总碳浓度变化及二氧化碳生成速度的变化规律,研究了光催化氧化与直接光解反应的不同,并着得比较了当反应条件如催化剂量,气相氧浓度以及光强度变化对两种反应的影响。实验结果证明了两种反应的历程和产物各不相同,多相光催化氧化更有利于有机物分子的降解,而光解作用会引起聚合反应,同时也说明充分利用太阳能不仅是开发光催化水处理技术的重要途径,也是抑制直接光解加 相似文献
995.
996.
研究了用电子捕获检测器测定大气中多种卤代烃化合物的气相色谱方法.选择的色谱分离柱有气液色谱柱25%DC-200 Chromosorb WAW DCMS(60—80目)和气固色谱柱carbopack CHT(80—100目).在等温条件下,以直接采样和直接进样方式分别测定了大气中多种卤代烃成份,并且比较了两根色谱柱的分析结果间的差异.在北京地区初步测定了主要的卤代烃如CFC-11,CFC-12,CHCl_3,CH_3CCl_3,CCl_4,CHCl=CCl_2和CCl_2=CCl_2的含量,其各自相应的浓度分别是127±24,275±12,49±32,80±27,60±18,8±2和30±17ppt(V/V). 相似文献
997.
硒化kappa-卡拉胶对烟民生理损伤的修复作用 总被引:2,自引:0,他引:2
本实验选择19例年龄在39—59之间,烟史为15—30a,每日吸烟量为6—20支的男性为对象,连续服用硒化kappa-卡拉胶(100ug硒/d)三个月后,对几项指标的测定结果表明:微核、双链DNA及血硒水平均有明显差异,服硒前,19例烟民中微核淋巴细胞出现率为73.7%,淋巴细胞微核出现率为1.26±1.04‰,服硒后,微核淋巴细胞出现率为42.1%,淋巴细胞微核出现率为0.52±0.70‰,P<0.01;服硒前,双链DNA的含量为7.76±2.59%,服硒后增至10.5±2.19%,P<0.01;血硒水平变化更为明显,由服硒前的76.4±15.1ppb增至服硒后的148.3±44.1ppb,P<0.01.全部病例无任何毒、副反应。实验结果初步表明:硒化kappa-卡拉胶对烟民的生理损伤具有一定的修复作用。 相似文献
998.
The effect of intensity and quality of illumination on the photosynthesis of some tropical marine phytoplankton 总被引:2,自引:0,他引:2
Using solar energy as a source of illumination, photosynthesis in 11 species of marine plankton algae was studied as a function of light intensity. From the photosynthesis-light curve for each organism, the saturation points (I
k
) in different organisms were determined. Among the diatoms and flagellates, the highest I
k
(saturation point) values were found in Rhizosolenia styliformis and Dinophysis miles respectively. When the organisms were exposed to a portion of the visible spectrum starting from 700 m, the photosynthesis was found to be related to the radiant energy. The missing portions of the spectrum produced no significant change in the rate of photosynthesis. The photosynthetic response shown by the different organisms was strikingly similar, which signifies that, despite the qualitative dissimilarities which the organisms may possess in their pigment composition, they are capable of much chromatic adaptation. 相似文献
999.
A survey was done in 15 typical villages, 150 soil and 86 vegetable plant samples were taken in Jiaxin prefecture of the Taihu Lake region, northern Zhejian province. Results indicate that after 15-20 years land use changed from the paddy rice-wheat (or oilseed rape) double cropping system, to a continuous vegetable land has caused soil quality dramatic change. (1) Acidification: average soil pH was 5.4; about 61% of total samples were pH < 5.5. It was 0.9 units lower than 10 years ago with same upland vegetable cultivation and was 1.2 units lower than soil pH of paddy rice-wheat (or oilseed rape) rotation. (2) Fertilizer salt accumulation: the average salt content was 0.28%, among these about 36.2% of the total samples contained more than 0.3%. (3) Nitrate N and available phosphorus (P) over accumulation: on average it was 279 mg NO3-N/kg, and 45-115 mg P/kg. Nitrate N four times higher and available P 4-10 times more than it is in present paddy rice-wheat rotation soils respectively. This has caused wide concern because of possible groundwater and well drinking water pollution by leached nitrate N and the P losses to water by runoff from vegetable lands induce surface water eutrophication. 相似文献
1000.
The spatial distribution of chlorophyll in three coral species carrying invertebrate symbionts was determined using spectral imaging techniques. From each pixel of the image, full fluorescence spectral data was obtained as well as comparative ratios of fluorescence. The multipixel fluorescence map and the relative-intensity fluorescence ratios demonstrated a high concentration of chlorophyll a next to the pits of Cryptochirus coralliodytes in Favites halicora. Spectral similarity maps of Goniastrea retiformis infested with Lithophaga lessepsiana and of Millepora dichotoma infested with Savignium milleporum revealed relatively higher chlorophyll concentrations in these two corals next to the symbionts. We hypothesize that the invertebrate symbionts fertilize their immediate surroundings with their excreta, enhancing algal growth. The spectral analysis system used in this study made it possible to distinguish such changes by spatial quantitation of the fluorescence emitted from small surface areas. 相似文献