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81.
根据环境监测质量保证和质量控制的要素和特点,在环境监测管理信息系统(EMM IS)中设计出相应模块,使得质控人员从人员、仪器设备、方法标准和实验室内的质控方法等方面非常方便快捷地判断出监测数据的是否符合。  相似文献   
82.
Amethodforcalculatingthetotalozoneamountintheclearskies¥BaiJianhui;WangGengchen(InstituteofAtmosphericPhysics,ChineseAcademyo...  相似文献   
83.
示波极谱滴定法测定工业废水中的硫化物   总被引:3,自引:0,他引:3  
在pH为5.5的醋酸-醋酸钠-氯化钾底液中,用Cu~(2+)离子沉淀硫化物,过量的Cu~(2+)离子用标准8-羟基喹啉溶液回滴,以8-羟基喹啉在单微铂电极示波极谱图上的敏锐切口指示滴定终点。废水的色度、浊度等对测定不产生干扰,无须进行预蒸馏处理,操作简便、快速。方法的相对偏差小于1.0%,变异系数小于0.6%,水样的加标回收 率为97—103%。  相似文献   
84.
以纳米TiO_2为催化剂,采用超声-紫外光协同催化体系降解水中菲,并考察了菲降解率的影响因素。实验结果表明:不同类型TiO_2对菲降解率的大小顺序为锐钛矿型TiO_2P25型TiO_2金红石型TiO_2;超声-紫外光协同催化体系对菲的降解率大于单独超声体系或紫外光催化体系,且均遵从一级反应动力学规律;在超声频率为60k Hz、声强为0.233 W/cm2、TiO_2投加量为0.06 g/L、pH为4.0、H_2O_2浓度为19.59 mmol/L的条件下降解75 min后,超声-紫外光协同催化体系对初始质量浓度为0.96 mg/L的菲的降解率可达76.78%。  相似文献   
85.
The passive sampling technique, diffusive gradients in thin films (DGT) has attracted increasing interests as an in-situ sampler for organic contaminants including per- and polyfluoroalkyl substances (PFAS). However, its effectiveness has been questioned because of the small effective sampling area (3.1 cm2). In this study, we developed a DGT probe for rapid sampling of eight PFAS in waters and applied it to a water-sediment system. It has a much larger sampling area (27 cm2) and as a result lower method quantification limits (0.15 – 0.21 ng/L for one-day deployment and 0.02 – 0.03 ng/L for one-week deployment) and much higher (by > 10 factors) sampling rate (100 mL/day) compared to the standard DGT (piston configuration). The sampler could linearly accumulate PFAS from wastewater, was sensitive enough even for a 24 hr deployment with performance comparable to grab sampling (500 mL). The DGT probe provided homogeneous sampling performance along the large exposure area. The use of the probe to investigate distributions of dissolved PFAS around the sediment-water interface was demonstrated. This work, for the first time, demonstrated that the DGT probe is a promising monitoring tool for trace levels of PFAS and a research tool for studying their distribution, migration, and fate in aquatic environments including the sediment-water interface.  相似文献   
86.
Zn-air batteries (ZABs), especially the secondary batteries, have engrossed a great interest because of its high specific energy, economical and high safety. However, due to the insufficient activity and stability of bifunctional electrocatalysts for air-cathode oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) processes, the practical application of rechargeable ZABs is seriously hindered. In the effort of developing high active, stable and cost-effective electrocatalysts, transition metal nitrides (TMNs) have been regarded as the candidates due to their high conductivity, strong corrosion-resistance, and bifunctional catalytic performance. In this paper, the research progress in TMNs-based material as ORR and OER electrocatalysts for ZABs is discussed with respect to their synthesis, chemical/physical characterization, and performance validation/optimization. The surface/interface nanoengineering strategies such as defect engineering, support binding, heteroatom introduction, crystal plane orientation, interface construction and small size effect, the physical and chemical properties of TMNs-based electrocatalysts are emphasized with respect to their structures/morphologies, composition, electrical conductivity, specific surface area, chemical stability and corrosion resistance. The challenges of TMNs-based materials as bifunctional air-cathode electrocatalysts in practical application are evaluated, and numerous research guidelines to solve these problems are put forward for facilitating further research and development.  相似文献   
87.
The interprovincial trade embodied carbon emissions plays an important role in the national emission reduction target among China’s provinces. Furthermore, it will affect the smooth start-up of the national carbon trade market as well as the implementation of targets in 2030 for dealing with the climate change. Based on constructed MRIO model, this paper analyzes the embodied carbon emission trade flows among Beijing, Tianjin, Hebei and surrounding regions such as Shanxi, Shaanxi, and Inner Mongolia. The results indicate that six provinces have formed different patterns of carbon trade balance, where Beijing, Tianjin, and Hebei provinces are in a deficit position, while the other three provinces are in a surplus position. Beijing, Tianjin, and Hebei have transferred part of the carbon emissions to the other three provinces, which shows greater heterogeneity among various provinces and provincial different sectors. On basis of the conclusions, this paper puts forward some suggestions on provincial decomposition, responsibility distribution, and provincial collaborative reduction for national emission reduction targets.  相似文献   
88.
通过对教学环境的系统分析(自然环境、社会环境),发现在体育教学中,社会环境因素对体育教学质量、效果的影响以及相互关系。提出了科学掌握和利用教学环境,顺应社会环境的变化发展而自我完善,促进提高体育教学质量。  相似文献   
89.
絮凝剂PFCS的制备及其性能研究   总被引:37,自引:0,他引:37  
利用H2SO4-HCl混酸溶解轧钢废钢渣的溶出液作原料,制成一种新型无机高分子絮凝剂聚合氯硫酸铁。试验了它的絮凝性能,并与聚全硫酸铁的絮凝效果进行了比较。实验结果表明:PFCS在pH=6-9的范围内具有良好的絮凝去浊性能;絮凝条件相同,将浊工为425度的黄河水样处理至5度以下,PFCS的投用量仅需10mg/L,而PFS的投用量至少需25mg/L。  相似文献   
90.
Adsorption experiments were carried out to investigate the sorption behaviors of naphthalene and phenanthrene in six different soils and to determine the effects of temperature, linear alkylbenzene sulfonate (LAS) and cetylrimethyl ammonium bromide (CTAB) on sorption. The results show that for a given sorbent phenanthrene exhibited greater nonlinear and stronger sorption than naphthalene. There was a strong negative correlation for the Koc values with organic carbon content (foc). The increase of temperature was not favorable to sorption. Sorption decreased along with the increasing aqueous LAS concentration from 0 to 1000 mg/L. At low CTAB concentration (< 100 mg/L), the adsorption increased as CTAB hemimicelles formed on the soil surface. At high concentration, CTAB decreased the adsorption by occupying active hydrophobic adsorption sites and solubilization of naphthalene and phenanthrene.  相似文献   
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