氮、硫输入对河口湿地土壤有机碳矿化的实验研究

通过室内培养实验,研究了氮、硫输入对闽江河口湿地土壤有机碳矿化和土壤理化性质的影响.结果表明:NH_4Cl(N1)、NH_4NO_3(N3)、K_2SO_4(S)和NH_4Cl+K_2SO_4(NS1)处理显著促进了湿地土壤有机碳矿化速率(p0.05),较对照分别提高了76.57%、60.09%、83.20%和52.59%,并且不同处理下土壤有机碳矿化速率均表现为随培养时间的增加而递减.氮、硫输入在不同时间对湿地土壤有机碳矿化的影响不尽一致,在前6 d各处理的促进作用最明显.湿地土壤有机碳累积矿化量在不同处理下均表现为随培养时间逐渐增加,其增长速率在培养初始阶段较快,而后逐渐减慢;不同培养时间有机碳累积矿化量在N1、N3、S和NS1处理下与对照处理间均存在显著差异(p0.05).短期培养结束后,N3、NS1处理显著增加了湿地土壤DOC含量(p0.05);N1、N3、NS1和NH_4NO_3+K_2SO_4(NS3)处理均显著增加了土壤NH_4~+-N含量(p0.05);KNO_3(N2)、N3、NS2和NS3处理均显著增加了土壤NO_3~--N含量(p0.05);S、NS1、NS2和NS3处理均显著增加了土壤SO_4~(2-)含量(p0.05).不同处理下湿地土壤Cl-、pH、EC具有微弱的波动变化特征,但在不同处理组间均不存在显著差异(p0.05).多元回归分析显示,DOC、NH_4~+-N和SO_4~(2-)是氮、硫输入处理下影响闽江河口湿地土壤有机碳矿化速率的主要控制因素.     

Polycyclic aromatic hydrocarbon concentrations, compositions, sources, and associated carcinogenic risks to humans in farmland soils and riverine sediments from Guiyu, China

The concentrations of 16 priority polycyclic aromatic hydrocarbons(PAHs) were measured in 23 farmland soil samples and 10 riverine sediment samples from Guiyu, China, and the carcinogenic risks associated with PAHs in the samples were evaluated. Guiyu is the largest electronic waste(EW) dismantling area globally, and has been well known for the primitive and crude manner in which EWs are disposed, such as by open burning and roasting. The total PAH concentrations were 56–567 ng/g in the soils and 181–3034 ng/g in the sediments.The Shanglian and Huamei districts were found to be more contaminated with PAHs than the north of Guiyu. The soils were relatively weakly contaminated but the sediments were more contaminated, and sediments in some river sections might cause carcinogenic risks to the groundwater system. The PAHs in the soils were derived from combustion sources,but the PAHs in the sediments were derived from both combustion and petroleum sources.     

铁还原降解饮用水中三氯丙酮的研究

铁刨花还原去除低浓度三氯丙酮(TCAce)的效果较好,当铁刨花的投加量为120 g/L,TCAce溶液浓度为20μg/L时,去除率为70.59%。铁刨花投加量和温度是铁还原去除TCAce的重要影响因素,铁刨花投加量越大,TCAce的去除率越高。温度越高,TCAce的去除率也越高。当TCAce浓度较低时,TCAce初始浓度的变化对TCAce的去除效果影响不大。铁还原去除TCAce的过程符合一级反应动力学方程。     

基于模糊FMEA法的乏燃料剪切机剪切装置风险评估

为了有效控制乏燃料后处理立式送料剪切机剪切装置在运行过程中的风险,采用基于模糊理论的故障模式及影响分析(FMEA)对剪切装置的故障模式进行风险评价。首先将风险优先指数(RPN)的3个评价指标视为模糊变量并模糊化,接着采用专家打分的方式对各故障模式进行模糊评价,采用重心法解模糊化,计算得出各故障模式的模糊风险优先指数(FRPN),从而确定机械设备中各故障模式的风险控制顺序。利用模糊FMEA法对乏燃料立式送料剪切机剪切装置的故障模式进行了风险评估,结果表明,吊篮焊接件裂纹、主刀体破损、刀具退刀固定档板变形为风险较大的故障模式,分析结果与工程实际较吻合。     

An empirical research on the determinants of Chinese college students’ carbon label cognition and interpersonal communication willingness

Carbon labels are innovative medium and tools for climate change communication and low-carbon marketing. This study aims at examining how college students are aware of low-carbon and carbon labels, whether they are more willing to communicate low-carbon ideas, and also the determinants affecting their interpersonal communication of carbon labels. The multiple regression analysis shows that Chinese college students’ willingness of interpersonal communication of carbon labels are significantly influenced by their awareness of climate change crisis, the perceived value of carbon labels, the consideration of product environmental attributes, the preferences of carbon labels, the household background, and their educational background. In response to these factors, this paper proposes, in a public perspective, the strategies to enhance the dissemination of carbon labels.     

中国风机制造技术转移模式与技术进步效果评价

根据技术转移过程中技术受方的性质,将中国风机制造技术转移分为"外商独资企业"、"中外合资企业"和"中资企业"三种模式.通过技术转移的层次、技术先进程度、技术转移的规模、技术转移的速度,对三种模式下技术转移的效果进行了评价.研究发现,通过技术转移,中国风机制造技术有了迅速的发展,但落后于国际先进水平的情况仍没有改变.中资企业的技术转移模式在转移技术的层次、技术转移规模和技术转移速度上,都要优于外商独资企业和中外合资企业模式,对中国风机制造技术进步的作用更大.在此基础上,本文提出,在中资企业模式下,在引进技术的同时,积极消化吸收,并重视与外国企业开展联合研发,才能最终获得创新能力.这也应当成为中国政府激励政策作用的重点.     

整组阳极板振打加速度有限元分析

采用有限元分析软件ABAQUS,对电除尘器整组阳极板振打加速度进行有限元分析计算。计算结果反映了极板上的加速度值以及加速度的分布规律,计算结果与实际情况吻合。因此有限元法为整组阳极板振打加速度的求解提供了一种简单有效的方法,同时为电除尘器的设计和改造提供了参考。     

Preparation of hydrogen-rich gas from waste polyurethane foam by steam gasification and catalytic reforming in a two-stage fixed bed reactor

Journal of Material Cycles and Waste Management - The reclamation of waste rigid polyurethane foam (WRPUF) is capable of realizing both circulations of waste and protection of the environment. In...     

Bioaccumulation,subcellular, and molecular localization and damage to physiology and ultrastructure in Nymphoides peltata (Gmel.) O. Kuntze exposed to yttrium

Bioaccumulation, subcellular distribution, and acute toxicity of yttrium (Y) were evaluated in Nymphoides peltata. The effects of Y concentrations of 1–5 mg L^?1 applied for 4 days were assessed by measuring changes in photosynthetic pigments, nutrient contents, enzymatic and non-enzymatic antioxidants, and ultrastructure. The accumulation of Y in subcellular fractions decreased in the order of cell wall > organelle > soluble fraction. Much more Y was located in cellulose and pectin than in other biomacromolecules. The content of some mineral elements (Mg, Ca, Fe, Mn, and Mo) increased in N. peltata, but there was an opposite effect for P and K. Meanwhile, ascorbate, and catalase activity decreased significantly for all Y concentrations. In contrast, peroxidase activity was induced, while initial rises in superoxide dismutase activity and glutathione content were followed by subsequent declines. Morphological symptoms of senescence, such as chlorosis and damage to chloroplasts and mitochondria, were observed even at the lowest Y concentration. Pigment content decreased as the Y concentration rose and the calculated EC₅₀ and MPC of Y for N. peltata were 2 and 0.2 mg L^?1 after 4 days of exposure, respectively. The results showed that exogenous Y was highly available in water and that its high concentration in water bodies might produce harmful effects on aquatic organisms. N. peltata is proposed as a biomonitor for the assessment of metal pollution in aquatic ecosystems.