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本文从摩尔吸光系数ε出发,推算出分子吸收分光光度法中校准曲线的斜率b0,并确定出斜率值的允许范围。通过对我站历次所做校准曲线进行研究,发现它们的斜率范围与本文所确定的范围符合得较好。 相似文献
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紫外线消毒技术在污水处理中的应用 总被引:19,自引:0,他引:19
我国日益突出的城市缺水和水污染问题使得污水回用受到重视,而消毒处理是其中关键,针对污水消毒处理中传统化学杀菌法的缺点,紫外线消毒法因其安全,易操作,杀菌快速有效的优点而有着广阔的应用前景。 相似文献
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本文报道了三氯化铁及聚氯化铁溶液的吸收光度,以及三氯化铁转化为聚铁化合物过程中吸光度的变化规律,建立了吸光度与实测盐基度及理论盐基度的相关方程,并考察了三氯化铁聚合过程中体系摩尔吸光系数的变化,提出根据摩尔吸光系数可以判断聚铁化合物的形态。 相似文献
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Sari Vilhunen Heikki Särkkä Mika Sillanpää 《Environmental science and pollution research international》2009,16(4):439-442
Background, aim, and scope The novel system of ultraviolet light-emitting diodes (UV LEDs) was studied in water disinfection. Conventional UV lamps,
like mercury vapor lamp, consume much energy and are considered to be problem waste after use. UV LEDs are energy efficient
and free of toxicants. This study showed the suitability of LEDs in disinfection and provided information of the effect of
two emitted wavelengths and different test mediums to Escherichia coli destruction.
Materials and methods Common laboratory strain of E. coli (K12) was used and the effects of two emitted wavelengths (269 and 276 nm) were investigated with two photolytic batch reactors
both including ten LEDs. The effects of test medium were examined with ultrapure water, nutrient and water, and nutrient and
water with humic acids.
Results Efficiency of reactors was almost the same even though the one emitting higher wavelength had doubled optical power compared
to the other. Therefore, the effect of wavelength was evident and the radiation emitted at 269 nm was more powerful. Also,
the impact of background was studied and noticed to have only slight deteriorating effect. In the 5-min experiment, the bacterial
reduction of three to four log colony-forming units (CFU) per cubic centimeter was achieved, in all cases.
Discussion When turbidity of the test medium was greater, part of the UV radiation was spent on the absorption and reactions with extra
substances on liquid. Humic acids can also coat the bacteria reducing the sensitivity of the cells to UV light. The lower
wavelength was distinctly more efficient when the optical power is considered, even though the difference of wavelengths was
small. The reason presumably is the greater absorption of DNA causing more efficient bacterial breakage.
Conclusions UV LEDs were efficient in E. coli destruction, even if LEDs were considered to have rather low optical power. The effect of wavelengths was noticeable but
the test medium did not have much impact.
Recommendations and perspectives This study found UV LEDs to be an optimal method for bacterial disinfection. The emitted wavelength was found to be an essential
factor when using LEDs; thus, care should be taken in selecting the proper LED for maximum disinfection. 相似文献
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The objective of this study was to test the feasibility of a new method to improve the accuracy in the estimation of sewage
components. Adding to the regression of sewage components with UV (ultraviolet) absorbance values, a proposed method considered
an unclear but existing relationship among characteristic of sewage production. Sewage production showed very defined profiles
due to the daily human activities. So the main idea was the combination of measuring the UV absorbance values and analyzing
the characteristics of the sewage production. For this purpose, 446 sewage samples taken at every 2-h interval for 51 days
at a wastewater treatment plant were statistically analyzed using neural network (NN). NN was trained with 350 data sets (about
29 days) of UV absorbance values, flow rate and time. And as a result, it could predict 96 data (12 days) as a validation,
indicating that estimation accuracies were improved to higher level than those of the linear regressions. The proposed method
could estimate concentrations of total nitrogen (TN) and total phosphate (TP) within practical accuracies as well as total
suspended solid. 相似文献
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