基于剪切波速的土体液化概率判别法∗

采用极大似然法对确定性剪切波速液化判别模型进行了标定,在此基础上提出了基于剪切波速的土体液化概率判别模型。结果表明,由对数正态分布、正态分布、最小耿贝尔分布以及最大耿贝尔分布获得的液化判别曲线在液化概率为5%和15%时有一定差异,在液化概率为35%时区别不大。根据贝叶斯信息准则,由最小耿贝尔模型标定的模型修正系数与液化案例数据库符合程度最好。Andrus和Stokoe液化模型修正系数的均值为0.879,说明该模型获得的安全系数从平均意义上小于真实安全系数;变异系数为0.387,表明该模型具有一定程度的模型不确定性。本文所建立概率模型的液化判别曲线与文献中基于贝叶斯映射函数获得的液化判别曲线较为一致,与文献基于逻辑回归方法获得的液化判别曲线在高循环应力比区域有较大差异。     

气候工程对中国不同等级降雨结构的可能影响

气候工程作为人类快速有效给地球降温的手段,在应对气候变化的国际谈判中越来成为各界讨论的焦点话题之一。为诊断当前GeoMIP设定的当量下,气候工程不同实施阶段是否对中国降雨结构产生影响。依据中国气象局中央气象台的日降雨强度划分标准,基于BNU~ESM模式的太阳辐射管理气候工程G4实验和RCP4.5情景下非气候工程的0.5°×0.5°空间分辨率日值降水数据,对比分析气候工程实施的3个不同时段,即2010~2099、2020~2069和2070~2099年,中国不同等级降雨雨量和雨日贡献率空间差异特征。结果表明：(1)在气候态上,3个时段两种情景下的中国不同等级降雨结构的气候态高低分异特征具有较好的一致性。气候工程并未改变中国降雨结构的空间高低分异特征。(2)在气候工程与非气候工程差异上,气候工程实施的不同阶段确实可以对中国不同区域的降雨结构产生影响,且不同时段差异性有所不同。(3)在气候工程实施前后差异上,气候工程实施中相比实施后促进了中雨、大雨和总暴雨事件,而抑制了小雨事件。在当前GeoMIP模式设定的当量下,气候工程实施会对中国降雨结构会产生不同层面的影响。     

应用流式细胞技术研究种群初始状态对藻类毒性效应的影响

应用流式细胞技术研究种群初始状态的变化及外源种群介入对藻类毒性效应的影响.结果表明:初始细胞密度的增加可以降低Cu2 的毒性效应.当微囊藻初始细胞密度从103上升到105cells·ml-1时,24h Cu2 处理后微囊藻酯酶活性的EC50值从4.4μg·l-1上升到37μg·l-1.而外源种群(栅藻、小球藻)的介入也可降低Cu2 对微囊藻的毒性效应.     

Genotoxicity evaluation and a primary risk assessment of organic pollutants in the drinking water sources of Nanjing, China

An increasing number of industrial, agricultural, and commercial chemicals in the aquatic environment leads to various deleterious effects on organisms, which is becoming an increasingly serious problem in China. In this study, the comet assay was conducted to investigate the genotoxicity to human body caused by organic concentrates in the drinking water sources of Nanjing City from Yangtze River of China, and health and ecology risk due to expose to these organic pollutants were evaluated with the multimedia environmental assessment system （MEAS）. For all the water samples, they were collected from four different locations in the drinking water sourcr samples, es of Nanjing City. The results of the comet assay showed that all the organic concentrates from the water samples could induce different levels DNA damages on human peripheral blood lymphocytes, and a statistically significant difference （p〈0.01） was observed compared with the solvent control, which demonstrated the genotoxicity was in existence. According to the ambient severity （AS） of individual compound, we had sorted out the main organic pollutants in the drinking water source of the four waterworks, and the results showed that there was some potential hazard to human body for all the source water, namely the total ambient severity （TAS） of health for each water source was more than 1. However, the TAS of ecology for each water source was less than 1, which indicated that it was safe to ecology. The results of this investigation demonstrate the application of the comet assay and the MEAS in aquatic environmental monitoring studies, and the comet assay found to be fast, sensitive, and suitable for genotoxicity monitoring programs of drinking water source.     

Zeolite powder addition to improve the performance of submerged gravitation-filtration membrane bioreactor

In this study, the effect of zeolite powder addition on submerged membrane bioreactor （SMBR） on membrane permeability, and the removals for COD, NH3-N, TN were investigated. Through the parallel operation of control and test systems, it was found that the zeolite powder addition could alleviate the ultra-filtration membrane fouling and enhance the membrane permeability. On the basis of experimental investigations, a concept of ＂protection coating layer＂ was proposed to illustrate the phenomenon of UF membrane fouling. In addition, the removal for COD in test system was more stable, a little higher compared to the control system. Due to the combination of nitrification and ion exchange, a more excellent removal for NH3-N in test system was obtained regardless of influent NH3-N loading rate. It was also found that a mean 25% higher TN removal took place in the test system, and ion exchange and simultaneous nitrification and de-nitrification were analyzed to be main factors. During the stable operation period, the SOURs of test zeolite powder added sludge and control activated sludge were measured to be 75 mgO2/（gMLVSS, h） and 24 mgO2/（gMLVSS, h） respectively, it meant that the zeolite powder addition could enhance the microorganism activity significantly.     

Pilot plant study on ozonation and biological activated carbon process for drinking water treatment

A study on advanced drinking water treatment was conducted in a pilot scale plant taking water from conventional treatment process. Ozonation-biological activated carbon process （O3-BAC） and granular activated carbon process （GAC） were evaluated based on the following parameters： CODMn, UV254, total organic carbon （TOC）, assimilable organic carbon （AOC） and biodegradable dissolved organic carbon （BDOC）. In this test, the average removal rates of CODMn, UV254 and TOC in O3-BAC were 18.2%, 9.0% and 10.2% higher on （AOC） than in GAC, respectively. Ozonation increased 19.3-57.6 μg Acetate-C/L in AOC-P17, 45.6-130.6 μg Acetate-C/L in AOC-NOX and 0.1-0.5 mg/L in BDOC with ozone doses of 2 8 mg/L. The optimum ozone dose for maximum AOC formation was 3 mgO3/L. BAC filtration was effective process to improve biostability.     

黄河三角洲自然保护区国土空间变化遥感监测与评价

为了解人类活动对黄河三角洲国家级自然保护区生态环境的影响,利用2000年至2019年的卫星影像数据,分析了黄河三角洲自然保护区近20年来土地利用的变化情况,并利用开发干扰指数定量分析了土地利用变化对自然保护区的影响。得出主要结论如下:黄河三角洲自然保护区近20年土地利用变化明显,草地、耕地和未利用地等土地利用面积下降,而建设用地（城乡居民点、工矿用地）和水域湿地等面积增加。变化面积占自然保护区总面积的47.0%,减少的草地和耕地等主要转为建设用地、水域湿地,主要表现为实验区内盐田和养殖塘面积的增加。2000年以来黄河三角洲自然保护区开发干扰指数逐年增大,2005年之前人类活动干扰相对轻微;2005年至2016年人类活动干扰剧烈,自然保护区开发干扰指数增加迅速,以盐田和养殖塘的开发为主要影响因素;2016年后自然保护区的监督管理力度加大,开发干扰指数趋于稳定。人类活动干扰呈现从轻微到剧烈再到稳定的过程。     

丛枝菌根真菌在矿区生态环境修复中应用及其作用效果

针对煤矿区生态环境修复中存在的主要问题,研究丛枝菌根真菌与紫穗槐共生状况,丛枝菌根真菌对紫穗槐根系发育的影响及其对煤炭开采塌陷区退化土壤的改良效应.结果表明,接种菌根5个月后,接种丛枝菌根促进紫穗槐地上部分和根系生长,提高了紫穗槐根系侵染率;接种区紫穗槐根际土壤中球囊霉素、易提取球囊霉素含量显著增加;接种菌根提高了紫穗槐根际土壤有效磷和有机质含量,微生物数量明显提高,取得较好的菌根生态效应.接种菌根有利于对矿区根际土壤的改良,促进了矿区生态系统稳定,对维持矿区生态系统的持续性具有重要意义.     

城市生物多样性问题及保护对策探讨

结合秦皇岛市的实际,对城市生物多样性现状和特点、生物多样性保护存在的问题进行了讨论,并提出了城市生物多样性保护的对策。      

黄柏河库湾水体富营养化评价及防治初探

葛洲坝水库蓄水以后,在黄柏河下游形成具有湖库特征的库湾。库湾水动力条件改变加之上游输入充足的营养物质,使库湾发生富营养化。利用黄柏河1998-2002年库湾断面监测资料评价其富营养化现状,分析富营养化成因,提出可行的防治措施,为国内同类水体富营养化防治提供参考。