BP人工神经网络模型在地下水水质评价中的应用

为了能够客观地对地下水水质进行综合评价,本文以西鞍山矿区为例,采用基于BP人工神经网络模型的评价方法对区内14个地下水水质监测点的水质进行了评价。考虑到地下水水质随季节性变化不大,以枯水期水质监测的主成分总硬度、溶解性总固体、硫酸盐、氯化物、铁和锰、硝酸盐、氟化物等指标作为评价因子,建立了地下水评价指标体系,并和模糊综合评价法的评价结果进行了比较,分类结果令人满意。评价结果表明,该模型设计合理、泛化能力强,对地下水水质评价具有较好的客观性、通用性和实用性,可为水质评价提供技术依据以及为有关部门治理水质提供理论依据和参考建议。     

流动注射分析仪检测水中挥发酚时假阳性的去除

挥发酚是《生活饮用水卫生标准》(GB 5749—2006)规定的必测项目,准确测定对水质检测意义重大。利用流动注射分析仪检测生活饮用水中的挥发酚,受水中总硬度(以Ca CO3计)的影响,检测结果出现假阳性,导致检测结果偏高,超标,严重干扰对水质的正确判断。西安市内供水硬度范围在60~300 mg/L,对于硬度在此范围内的水样,通过增大缓冲溶液铁氰化钾的浓度,即可显著消除总硬度对挥发酚检测的影响。铁氰化钾浓度控制在5.0 g/L,挥发酚浓度在0.00~100μg/L之间,相关系数可达到0.999 9。通过测定国家标准样品和加标回收试验,对方法进行验证,检出限、加标回收结果满足要求,检测结果真实可靠。     

基于层次分析的模糊综合评价法在水质评价中的应用

以西鞍山矿区为例,采用基于层次分析的模糊综合评价法对区内14个地下水水质监测点的水质进行了评价,考虑到地下水水质随季节性变化不大,以枯水期水质监测的主成分总硬度、溶解性总固体、硫酸盐、氯化物、铁和锰、硝酸盐、氟化物等指标作为评价因子,建立了地下水评价指标体系。评价结果表明,采用该方法进行水质评价是准确合理的,可为水质评价提供技术依据以及为有关部门治理水质提供理论依据和参考。     

北京市东城区学校直饮水卫生现况调查

目的了解北京市东城区学校内直饮水卫生现况,分析直饮水水质卫生学指标,为制定学校直饮水卫生管理办法提供科学数据。方法查阅东城区疾病预防控制中心2008—2013年受理的76份学校委托直饮水检测报告,选取24所学校,每所学校抽检1台直饮水设备,分别采集直饮水设备出口水和市政末梢水各1份,对结果进行统计分析。结果东城区学校直饮水总体水质良好,全项指标合格率为92%,不合格指标为菌落总数及浑浊度。直饮水与市政水相比,水中总硬度较低,铜较高。软水机相对于热能交换机,能大幅度降低市政水中氯化物、总硬度、氟化物、硫酸盐、铝、溶解性固体的含量,水质得到进一步净化。结论北京市东城区学校直饮水总体水质情况良好,直饮水相比市政水,总硬度降低,铜浓度升高。     

回弹法测定混凝土强度能力验证研究

介绍了北京市67个检测机构回弹法测定混凝土强度能力验证的测试情况。能力验证过程中,对检测机构的检测结果采用稳健(Robust)统计技术处理,减少了极端结果对平均值和标准偏差的影响。同时对统计分析的设计过程、能力验证统计结果及各机构的检测能力进行了分析。     

回弹法测定混凝土强度能力验证研究

介绍了北京市67个检测机构回弹法测定混凝土强度能力验证的测试情况。能力验证过程中,对检测机构的检测结果采用稳健（Robust）统计技术处理,减少了极端结果对平均值和标准偏差的影响。同时对统计分析的设计过程、能力验证统计结果及各机构的检测能力进行了分析。     

运用渐进回归正交法建立再生水管道腐蚀速率模型

以Cl~-、SO_4~(2-)、p H值和总硬度为典型水质因素,通过正交试验分析模拟再生水动态管网中上述水质因素对腐蚀速率的影响。通过正交极差分析发现,各水质因素对腐蚀速率的影响程度由大到小为:p H值总硬度SO_4~(2-)Cl~-。利用渐进优化多元线性回归法对得到的数据进行分析,建立了拟合度为0.998的再生水管道腐蚀速率水质因素影响数学统计模型。同时,采用再生水厂原水进行验证试验,并将获取的数据代入模型,结果表明该模型误差较低,模拟效果较好。     

岩土工程检测中存在的问题及解决对策探讨

文章从岩土选样、检测方式、检测重视程度、检验员素质四方面阐述了岩土工程检测中存在的主要问题,并提出对应的解决对策,希望提高岩土检测的质量。     

临汾市再生水厂工艺选择分析

针对进出水水质特点,经过技术经济分析,确定临汾市再生水厂采用曝气生物滤池、普通快滤池、连续微滤膜(CMF)和反渗透(RO)等工艺。经曝气生物滤池处理后,氨氮和总氮基本达到循环冷却水水质要求;CMF-RO工艺的应用则有效解决了总溶解性固体和总硬度问题。多种处理工艺的结合,既节约了工程投资,保证了出水水质稳定、可靠,又能够根据实际情况灵活调整,降低了运行、维护费用。     

丹江口水库水质的综合评价

采用基于层次分析的模糊综合评价法对丹江口水库水质进行了等级评价,选取氨氮、总氮、总磷、高锰酸盐指数、浊度、溶解性总固体、溶解氧、硬度、硫酸根、氯离子和p H等指标作为评价因子,建立了丹江口水库水质综合评价指标体系。评价结果表明,在低浊期,丹江口水库水质介于Ⅰ类~Ⅱ类水质之间,在高浊期,丹江口水库水质介于Ⅱ类~Ⅲ类水质之间。     

预应力夹片式锚具锚固性能的探讨

结合具体锚具静载锚固性能试验的实例，讨论了锚具本身质量、钢绞线硬度与锚具硬度的关系及全面质量管理等因素与锚固性能的关系，从而提出具体建议。     

稳健统计分析在比对试验能力验证中的应用

结合实例主要介绍了如何利用稳健统计技术对参加实验室间的比对或能力验证试验的检测结果进行分析和处理,并根据结果考核各实验室检测能力的优劣,为实验室比对试验能力验证中检测结果数据的分析和处理提供了方法和指导。     

A survey of tap water quality in Kuala Lumpur

A safe drinking water programme known as The National Drinking Water Quality Surveillance Programme (NDWQSP) was launched by the Ministry of Health, Government of Malaysia in 1983 to ensure safe practices in water treatment and distribution. The aim of this work was to assess the effectiveness of this programme in the improvement of tap water quality in and around Kuala Lumpur. The results indicate that there was no microbial contamination in 100 random samples collected from 20 selected areas. Other quality parameters such as colour, pH, turbidity, hardness, magnesium, sulphate and chloride were within acceptable limits. Heavy metals such as Cu²⁺, Pb²⁺, Cr (total), Ni²⁺, Cd²⁺, Fe (total) and Mn (total) were also under control. The only exception was Ba²⁺, which did not comply with the standard and was up to ten times higher than the guideline value. Moreover, there was significant variation in water quality as indicated by the test results.     

基于偏最小二乘回归的地震动复合强度参数构造与统计性分析

为解决某些地震动强度参数对某些结构有效性较好,而对其他结构有效性较差的问题,基于偏最小二乘回归提出一种地震动复合强度参数的构造方法。对构造的地震动复合强度参数与工程需求参数进行概率地震需求分析,从充分性、有效性、有益性和鲁棒性四个角度对地震动强度复合参数开展统计性分析。为校验所提方法的准确性,选择具有不同高度和不同抗震设防水平的16个钢筋混凝土框架结构为例,并遴选100条真实地震动记录作为地震输入。选取8个地震动强度参数作为基本参数,以结构最大层间位移角作为工程需求参数,采用偏最小二乘回归方法,构造地震动复合强度参数,并对其进行统计性分析。分析结果表明：偏最小二乘回归方法是一种较为合理构造地震动强度复合参数的方法,所构造的地震动复合强度参数具有比单个强度参数更优良的统计性,具有更好的有效性、有益性、充分性和鲁棒性。     

曝气生物滤池-化学沉淀-砂滤的中试应用

介绍了曝气生物滤池-混凝澄清-砂滤组合工艺的试验方法及其试验用水水质情况,并分析了该工艺对CODCr,NH3-N,总硬度,总磷的去除效果,得出了一些有意义的试验结论,为中水回用工程设计提供了可靠的参数。     

工业厂房超大面积耐磨地面一次性成型施工技术

当我们遇到厂房内要安装高精密仪器,业主要求地面具有高平整度、表面硬度高、密度大、耐磨、不生灰尘、不易剥离,传统的施工方法已无法保证其高质量的要求。这就要求我们必须采取有效的控制方法,并加强工序质量控制,才能达到更高的质量标准。结合广州海日花边有限公司生产基地主厂房地面施工,介绍超大面积耐磨地面的施工工艺及操作要点。     

浅谈如何有效利用能力验证结果进行实验室质量管理

能力验证作为一种重要的外部质量评价手段,可有效评估确认实验室相关技术能力。就实验室应如何合理分析并有效利用能力验证计划结果提升自身质量管理水平进行了简要阐述。     

Spatio-temporal change of water chemical elements in Lake Dianchi, China

Lake Dianchi is a large lake, which is listed in the 'Three Important Lakes Restoration Act in China'. The water quality has deteriorated from class II in the 1970s to class V today, with an attendant increase in the frequency and intensity of the formation of blue algae blooms. From 2003 to 2006, a water quality monitoring programme was implemented for eight regional zones in Lake Dianchi. It monitored the following substances: carbon (C), nitrogen (N), phosphorus (P), sulphur (S), calcium (Ca), magnesium (Mg), iron (Fe), potassium (K), sodium (Na), zinc (Zn), copper (Cu), manganese (Mn) and chlorine (Cl), together with water temperature, pH, total hardness and total salt content. Data were analysed using regression models to determine the impacts of these substances and conditions for the formation of blue algae bloom, and to assess their relationship with chlorophyll a . The results showed a significant relationship between chlorophyll a and C, P, N, Cl, Fe, Mg, water temperature, pH, total hardness and total salt. There was no significant relationship between chlorophyll a and total manganese (TMn), Mn, sulphate (SO₄²⁻), soluble total manganese STMn, Ca, Zn, K, Na and Cu. The study showed that the concentration of chlorophyll a in different regions of the lake was different, indicating that the mix of chemicals in a region has a different impact on pollution levels throughout Lake Dianchi.     

Monitoring of water quality from roof runoff: Interpretation using multivariate analysis

The quality of harvested rainwater used for toilet flushing in a private house in the south-west of France was assessed over a one-year period. Temperature, pH, conductivity, colour, turbidity, anions, cations, alkalinity, total hardness and total organic carbon were screened using standard analytical techniques. Total flora at 22 °C and 36 °C, total coliforms, Escherichia coli and enterococci were analysed. Overall, the collected rainwater had good physicochemical quality but did not meet the requirements for drinking water. The stored rainwater is characterised by low conductivity, hardness and alkalinity compared to mains water. Three widely used bacterial indicators - total coliforms, E. coli and enterococci - were detected in the majority of samples, indicating microbiological contamination of the water. To elucidate factors affecting the rainwater composition, principal component analysis and cluster analysis were applied to the complete data set of 50 observations. Chemical and microbiological parameters fluctuated during the course of the study, with the highest levels of microbiological contamination observed in roof runoffs collected during the summer. E. coli and enterococci occurred simultaneously, and their presence was linked to precipitation. Runoff quality is also unpredictable because it is sensitive to the weather. Cluster analysis differentiated three clusters: ionic composition, parameters linked with the microbiological load and indicators of faecal contamination. In future surveys, parameters from these three groups will be simultaneously monitored to more accurately characterise roof-collected rainwater.