空间环境下碳纤维/双马树脂基复合材料的性能演化及损伤机理

目的基于碳纤维/双马树脂基(CF/BMI)复合材料在航天结构材料中广泛的应用前景,研究其性能演化及损伤机理,为评估与预测其在空间环境下的服役性能及寿命提供理论依据。方法利用地面试验装置模拟不同的空间环境因素包括真空热循环、质子辐照和电子辐照,利用动态力学分析(DMA)、热重分析(TGA)、X射线光电子能谱(XPS)、热膨胀分析、原子力显微镜(AFM)和力学性能测试等手段系统地研究CF/BMI复合材料在空间环境下的性能变化及损伤行为。结果真空热循环能够引发复合材料产生脱气行为与界面脱粘效应,使其横向拉伸强度退化,弯曲强度和层间剪切强度受到热循环初期固化交联作用的影响,呈现先升高后降低的变化趋势。质子辐照导致材料表面层化学键断裂及碳化,使力学性能及热性能受到一定程度的损伤。电子辐照能够引发辐照交联和辐照降解作用,在较高束流量辐照下降解作用占据主导地位成为复合材料力、热性能退化的决定性因素。结论预期研究成果为CF/BMI复合材料在空间环境下的服役性能及寿命的评估与预测提供了必要的理论依据。     

磁性MZF@SiO2对水中Pb(Ⅱ)的吸附

为提高吸附剂固液分离性能,以锰锌铁氧体Mn_(0.6)Zn_(0.4)Fe_2O_4为磁核,利用正硅酸乙酯水解制备了核壳结构磁性吸附剂Mn_(0.6)Zn_(0.4)Fe_2O_4@SiO_2(MZF@SiO_2),以水中重金属Pb(Ⅱ)作为探针分子,研究了其吸附动力学、吸附等温线及吸附热力学,并通过Zeta电位、FT-IR红外光谱及X射线光电子能谱,对吸附机理进行了研究.结果表明,吸附动力学数据符合准二级动力学模型,Freundlich方程能更好地描述吸附等温行为;MZF@SiO_2对Pb(Ⅱ)的吸附为自发吸热过程,MZF@SiO_2对Pb(Ⅱ)的吸附机理为静电作用、阳离子交换和配位作用.MZF@SiO_2可采用0.01 mol·L-1硝酸进行再生.     

矿井生产环境下光透过性实验研究

通过实验模拟巷道生产作业环境,分析了矿井生产环境下光照衰减的机理,研究了普通LED灯、金卤灯、荧光灯、头戴LED矿灯4种灯具在不同环境参数下的透射性,得出其在不同矿井因素（粉尘浓度、风速、相对湿度）下光的透过性影响规律,结果表明:在矿井中风速和相对湿度的增加均能降低光的透过率,相对湿度变化对光的透过率影响较大,且风速和相对湿度的增加对粉尘浓度有一定的积聚作用。研究结果为井下照明灯具的合理选用提供了依据。     

亚青会期间南京大气PM_(2.5)中重金属来源及风险

为探究亚青会期间南京奥体中心附近大气PM2.5中重金属来源及潜在的健康风险,于2013年8月3~28日对PM2.5中重金属元素V、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Cd、Sn、Sb和Pb进行了观测分析.结果表明:受亚青会污染源调控和气象要素影响,亚青会前、中、后不同时期重金属浓度存在差异,亚青会期间各重金属的浓度均值低于亚青会前期.富集因子分析显示Cu、Zn、Cd、Sn、Sb和Pb为重度富集元素,污染程度为CdCuZnPbSbSn.聚类分析表明工业排放、燃煤、道路尘和机动车尾气排放是这些重金属的主要来源.亚青会期间,PM2.5中各重金属通过呼吸途径对运动员造成的非致癌风险均小于1,5种致癌重金属的风险指数均低于致癌风险阈值范围.     

黄河包头段冻融过程中PAHs的分布特征及来源解析

为研究黄河包头段冻融过程中PAHs(多环芳烃)的分布特征及来源,分别于2012—2014年流凌期、封河期及融冰期采集黄河包头段干流水相及冰相样品,分析该河段PAHs的时空分布特征,并通过主成分分析法探究污染物的来源. 结果表明,水相中共检测出11种PAHs,ρ(∑₁₁PAHs)的范围为6.58~222.37 ng/L,平均值为61.48 ng/L,其中Fla(荧蒽)为最主要的污染物,部分组分在个别采样点超出了EPA882-Z-99-001中规定的标准限值;冰相中共检测出8种PAHs,ρ(∑₈PAHs)的范围为4.91~59.39 ng/L,平均值为27.17 ng/L,ρ(4环PAHs)所占比例最大. ρ(PAHs)在水相与冰相中沿程分布规律一致,S2、S5采样点较高,S4、S7采样点相对较低. 水相冻融过程中,大部分采样点的ρ(PAHs)均在稳定封河时较高. 水相冻融过程中原有7种PAHs反应的信息可由3个因子来代替,分别代表生活污水及工业污废水排放源、煤燃烧排放源及交通源的污染,方差累积贡献率达80.00%.      

降水梯度序列下柠条林地土壤养分的空间变异

通过野外实地调查结合室内分析,研究陕西省境内不同降雨条件下的黄土高原同级树龄柠条林地土壤养分。结果表明,研究区土壤养分含量低,养分中有机质和全氮在降水梯度上的空间变异性显著;有机质和全氮含量在土壤剖面上表现为随着土层的加深逐渐减少,全磷含量在土壤剖面上表现为从表层到心土层逐渐降低,从心土层到底层逐渐增加;全钾含量在剖面上的规律与有机质和全氮相反;有机质、全氮、全磷、全钾含量均随着降水梯度的增加而增加;有机质含量与全氮、全钾呈现极显著正相关,与全磷呈现显著正相关关系。     

中药废水处理工程应用研究

西安市某制药厂中药废水具有水量水质变化大,可生化性较差的特点.采用电解+水解酸化+ ABR厌氧+接触氧化+絮凝沉淀组合工艺对其进行处理;平均进水p(CODcr)=4 600 mg/L,平均出水p(CODcr)=42 mg/L,CODcr平均去除率为99.1％.实践结果表明,该工艺运行费用低,操作简便,易于维护,处理效果稳定,其出水各项指标均优于《黄河流域(陕西段)污水综合排放标准》(DB 61/224-2011)二级标准.     

Toward a framework of environmental risk management for CO<Subscript>2</Subscript> geological storage in china: gaps and suggestions for future regulations

China encourages the demonstration of carbon capture and storage (CCS) projects. In an effort to identify gaps and provide suggestions for environmental risk management of carbon dioxide (CO₂) geological storage in China, this article presents a concise overview of potential health, safety and environmental (HSE) risks and environmental management regulations for CO₂ geological storage in Australia, Japan, the United States (USA), the European Union (EU), and the United Kingdom (UK). The environmental impact assessment (EIA) experience of Shenhua Ordos Coal-to-Liquid (CTL) Project and PetroChina Jilin Oil Field enhanced oil recovery (EOR) is subsequently analyzed in light of our field investigation, and gaps in current EIA guidelines that are applicable to CO₂ geological storage projects are identified. It is found that there are no specific environmental risk regulations suitable for CO₂ storage in China, and environmental risk management lags behind the development of CCS technology, which presents a challenge to demonstration enterprises in terms of assessing environmental risk. One major challenge is the overestimation or underestimation of this risk on the part of the enterprise, and another is a lack of applicable regulations for government sectors to supervise the risk throughout CCS projects. Therefore, there is a pressing need for China to formulate environmental management regulations that include environmental risk assessment, mandatory monitoring schemes, environmental emergency plans, and related issues.     

可见光催化剂Ag_3PO_4/海泡石的制备及降解染料废水性能

以沉淀法、离子交换法和原位法制备了Ag_3PO_4/海泡石复合光催化剂,采用XRD、FTIR、UV-Vis-DRS对其结构进行了表征,以可见光驱动催化降解日落黄染料为探针反应,考察了制备方法对催化剂光催化性能的影响。结果表明:Ag_3PO_4与海泡石成功复合并产生了协同作用,催化剂中Ag_3PO_4均为立方晶型,部分Ag_3PO_4进入了海泡石层间,改变了其晶面有序性并拓宽了层间距,海泡石对Ag_3PO_4的复合提高了Ag_3PO_4的稳定性和光催化活性;其中,离子交换法制备的光催化剂中Ag_3PO_4与海泡石的复合程度最高,Ag_3PO_4稳定性最强,光催化活性最好,在可见光驱动下,该催化剂对50 mg/L的日落黄降解率可达97.16%,并且对其他3种50 mg/L的染料废水的降解率也在86%以上,此外,该催化剂再生2次后仍保持良好的活性和稳定性。     

Strategies to combat desertification for the twenty-first century in China

SUMMARY

During the past half century, China has experienced increasingly severe land degradation, soil erosion, and desert expansion. Desertification is affecting one third of China's total territory and the annual accelerating rate of desertification spread is as high as 2460 km² in China. In 1996, China developed a National Action Programme to Combat Desertification (NAP), which is aimed to apply new legal measures and technical approaches to slow down desertification processes and achieve a long-term goal — control desertification and alleviate poverty through continuous efforts to fight against desertification, stabilize mobile dunes, revegetate degraded rangeland and control soil erosion in arid, semi-arid, and dry sub-humid areas. The long-term and integrated strategies of China's NAP result in encouragement of social participation, legal institutional guarantees, policy making, and establishment of demonstrations/pilot projects to combat desertification at both national and provincial level.