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101.
The lead removal from the metallic mixture of waste printed circuit boards by vacuum distillation was optimized using experimental design, and a mathematical model was established to elucidate the removal mechanism. The variables studied in lead evaporation consisted of the chamber pressure, heating temperature, heating time, particle size and initial mass. The low-level chamber pressure was fixed at 0.1 Pa as the operation pressure. The application of two-level factorial design generated a first-order polynomial that agreed well with the data for evaporation efficiency of lead. The heating temperature and heating time exhibited significant effects on the efficiency, which was validated by means of the copper–lead mixture experiments. The optimized operating conditions within the region studied were the chamber pressure of 0.1 Pa, heating temperature of 1023 K and heating time of 120 min. After the conditions were employed to remove lead from the metallic mixture of waste printed circuit boards, the efficiency was 99.97%. The mechanism of the effects was elucidated by mathematical modeling that deals with evaporation, mass transfer and condensation, and can be applied to a wider range of metal removal by vacuum distillation. 相似文献
102.
Observation-based methods are useful tools to explore the sensitivity of ozone concentrations to precursor controls. With the aim of assessing the ozone precursor sensitivity in two locations: Paterna (suburban) and Villar del Arzobispo (rural) of the Turia river basin in the east of Spain, the photochemical indicator O3/NOy and the Extent-of-Reaction (EOR) parameter have been calculated from field measurements. In Paterna, the O3/NOy ratio varied from 0 to 13 with an average value of 5.1 (SD 3.2), whereas the averaged value for the EOR was 0.43 (SD 0.14). In Villar del Arzobispo, the O3/NOy ratio changed from 5 to 30 with a mean value of 13.6 (SD 4.7) and the EOR gave an averaged value of 0.72 (SD 0.11). The results show two different patterns of ozone production as a function of the location. The suburban area shows a VOC-sensitive regime whereas the rural one shows a transition regime close to NOx-sensitive conditions. No seasonal differences in these regimes are observed along the monitoring campaigns. Finally, an analysis of the influence of the measurement quality of NOy, NOx and O3 on the uncertainty of the O3/NOy ratio and the EOR was performed showing that the uncertainty of O3/NOy is not dependent on either its value or the individual values of O3 and NOy but just on the quality of O3 and NOy measurements. The maximum uncertainty is 26% as long as the combined uncertainties of O3 and NOy remain below the 7.5%. The case of the EOR is different and its uncertainty depends on both the value of the EOR parameter and the individual concentration values of NOy and NOx. The uncertainty of the EOR estimation can be very high (>200%) if the combined uncertainties of both NOy and NOx are high (>7.5%), or especially, if u(NOy) and u(NOx) differ considerably from each other (>3.5%). 相似文献
103.
为研究细水雾灭火系统对18650型锂电池热失控的抑制效果,利用自设计实验平台进行抑爆实验,对比初爆与燃爆两个关键点及有无外部热源的温度变化图。研究表明,细水雾能够明显抑制18650型锂电池热失控,但施加细水雾的时间点对抑制效果影响较大,初爆后施加细水雾能够有效抑制,在燃爆后施加细水雾10s内温度降低200℃以上,但由于锂电池内部电解液复燃的特点,温度回升。温升速率的变化使得电池初爆的时间和温度分别提前了67.4%和44.4%,据此提出通过探测18650型锂电池初爆释放气体发现热失控发生并在最短时间内移除异常行为电池来控制电池热失控及其热量的异常传播。 相似文献
104.
钢筋混凝土结构抗火性能试验研究现状及存在的问题 总被引:1,自引:0,他引:1
在大量调研的基础上,从材料、结构和构件三个层次分析了目前混凝土结构抗火性能试验现状、存在的问题及解决方法。这些问题有的是关于试验标准和方法认识上存在一定争议的,有些是实验室和真实情况的不一致造成的,有些是目前技术水平限制所产生的,有些是目前试验领域缺乏研究或还没有认识到需要研究的问题,讨论了一些有价值的建议和研究方向,对今后混凝土结构抗火性能试验有借鉴意义。 相似文献
105.
106.
This work focuses on modeling and optimization of a sono-assisted photocatalytic decolorization process of a model pollutant, azo dye C.I. direct red 16 (DR16). In the process, a high temperature thermal decomposition nano synthesized titanium dioxide (TD-TiO2) was applied as photocatalyst. Central composite design (CCD) methodology was used for designing the experiments, modeling and optimization of the process. A quadratic model was established to describe dependency of the decolorization efficiency (DE), as the model response, to some effective operational parameters, i.e. the catalyst dosage, pH and the dye initial concentration. The ANOVA analysis confirmed that all of the variables have significant influence on the model response. Under the established optimum conditions, 92.4% DE was achieved after 45 min; however, to access desirable mineralization efficiency, the process should be continued up to 120 min. All withdrawn samples from the reaction media during the process showed no antibacterial activity, which indicates safety of the treated effluent for disposal into the environment. Also studies showed that the process proceeds via two parallel branches of photolysis and photocatalysis, where propagation of the ultrasonic waves into the reaction media plays a vital promoting role on the latter branch. 相似文献
107.
目前,大多数制药废水处理研究的方向是处理抗生素制药废水,缺乏对营养类型制药废水处理工艺方面的研究,通过对营养型制药废水处理工艺研究,可以得出废水处理相关的参数。在本文中,厌氧-好氧法废水处理工艺作为制药废水处理的最主要工艺,重点对营养型基础制药废水做出分析,对污水处理厂生产条件、运行参数进行实验研究。 相似文献
108.
在超燃冲压发动机扩张型燃烧室中,对凹腔内局部补氧的点火强化方法进行了试验研究。采用高速摄影手段研究了不同的补氧方式对凹腔内火焰分布特征和燃烧强度的影响,并针对并联双凹腔燃烧室构型,研究了在单侧凹腔补氧条件下向异侧凹腔的火焰传播过程。试验结果表明,采用凹腔内补氧的方式能调节凹腔内的燃料浓度分布、改善凹腔内的燃烧过程,控制燃烧放热强度;稳态燃烧情况下,观察到凹腔驻留火焰的两种存在特征,分别表现为:由回流区热量反馈机制作用下的凹腔局部驻留火焰和燃烧室全局压力反馈影响下的凹腔剪切层火焰。只有在单侧凹腔燃烧建立了全局压力反馈的条件下才能实现凹腔火焰的异侧传播。 相似文献
109.
厌氧生物法处理氨基酸发酵废水的实验研究 总被引:2,自引:0,他引:2
氨基酸是制药业的重要产品,伴随其生产过程会产生大量的发酵废液,该文对异光氨酸生产过程中所产生的高浓度机废水进行了厌氧生物处理的静态与动态实验。结果表明,在35℃,进水6.4-7.4,停留时间10h的情况下,最大有机负荷为8kg(COD)/m^3.d沼气产生率6.3L/kg(COD,COD去除率≥80%,在正常操作上,污泥负荷最高达达3.6kg(COD/kg(VSS).d 相似文献
110.
Silvia Ferrini Riccardo Scarpa 《Journal of Environmental Economics and Management》2007,53(3):342-363
Good practice in experimental design is essential for choice experiments used in nonmarket valuation. We review the practice of experimental design for choice experiments in environmental economics and we compare it with advances in experimental design. We then evaluate the statistical efficiency of four different designs by means of Monte Carlo experiments. Correct and incorrect specifications are investigated with gradually more precise information on the true parameter values. The data generating process (DGP) is based on estimates from data of a real study. Results indicate that D-efficient designs are promising, especially when based on Bayesian algorithms with informative prior. However, if good quality a priori information is lacking, and if there is strong uncertainty about the real DGP—conditions which are quite common in environmental valuation—then practitioners might be better off with shifted designs built from conventional fractional factorial designs for linear models. 相似文献