预腐蚀铝合金材料裂纹萌生寿命评估

铝合金在航空工业中广泛应用,因此对于铝合金构件的寿命评估很重要。利用扫描电子显微镜(SEM)原位观测技术,研究了预腐蚀铝合金试件在循环应力作用下的疲劳裂纹萌生和扩展行为。结果表明腐蚀坑对于裂纹萌生扩展行为具有强烈的影响。基于局部应变法,提出了一种预测带有腐蚀损伤的铝合金疲劳裂纹萌生寿命的评估公式。     

Ce-MCM-22分子筛的合成与吸附动力学研究

采用静态水热晶化法,以硅溶胶为硅源、六亚甲基亚胺(HMI)为模板剂,通过掺杂Ce合成了具有MWW层状结构的Ce-MCM-22分子筛。并利用粉末X-射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)等方法对其进行了表征,对其进行了吸附动力学的研究。研究表明,Ce-MCM-22吸附动力方程拟一级方程为y=-0.028 1x-0.136,R2=0.983 4。Ce-MCM-22吸附动力方程拟二级方程为y=0.465 7x+1.2005,R2=0.999 5,说明拟二级反应模型更能真实地反映分子筛吸附亚甲蓝溶液的反应机理。     

实时合成水滑石分离模拟放射性核素锶的研究

采用实时合成水滑石的方法从高放废液中分离模拟放射性核素锶,通过单因素实验并借助XRD分析确定了最佳分离实验条件,同时,运用FTIR、SEM等技术手段对合成的含锶水滑石的结构、形貌进行了分析.结果表明,当Sr2+初始浓度为70mg.L-1、pH值为10.5、n(Mg+Sr)/n(Al)为3时,锶的去除率最高可达95%以上;XRD和SEM分析结果表明,锶嵌入了水滑石的晶格中,合成的含锶水滑石形貌为层状六边形;含锶水滑石煅烧产物主要为尖晶石,且煅烧产物中未见氧化锶,表明嵌入到水滑石晶格中的锶在煅烧后存在于尖晶石的晶体结构中.     

氯苯紫外光降解产物对生物过滤塔运行性能的影响

生物过滤技术对难生物降解VOCs的处理效果较差,构建紫外光降解-生物过滤联合处理工艺是解决难生物降解VOCs处理的一个有效手段.已有研究表明,紫外光降解预处理对氯苯生物过滤塔的去除性能有促进作用.为了考察紫外预处理对生物过滤塔的影响机理,本研究分别考察了氯苯紫外光降解主要产物氯酚、乙酸以及副产物臭氧对生物过滤塔运行性能的影响.研究结果表明,加入乙酸降低了生物过滤塔的氯苯去除性能,在增加喷淋量后去除性能有所恢复.加入邻氯酚使生物过滤塔的氯苯去除性能略有降低.臭氧明显促进了生物过滤塔的氯苯去除性能,当进口臭氧浓度在60～120mg.m-3时,氯苯平均去除率可由70%提高到90%以上.因此,臭氧是紫外预处理促进生物过滤塔运行性能的主要因素.     

可生物降解材料聚羟基脂肪酸酯（PHA）的合成与应用概述

聚羟基脂肪酸酯（polyhydroxyalkanoates,PHA）是很多微生物合成的一种细胞内聚酯,是一种天然的高分子生物材料。PHA具有良好的生物相容性能、生物可降解性和塑料的热加工等性能。文章主要综述了PHA的合成途径与有关应用方面的研究。     

奶牛粪高温堆肥保氮与除臭技术实验研究

采用高温堆肥模拟试验研究了有效微生物EM和两种调理剂稻草、蚯蚓粪在奶牛粪堆肥中保氮和除臭的效应及各自适宜的添加比例。结果表明,在高温条件下,EM、稻草和蚯蚓粪均可明显降低奶牛粪中NH3和H2S的挥发,EM各添加比例的NH3去除率为7.06%～11.80%,H2S去除率为5.30%～10.81%;稻草各添加比例的NH3去除率为11.76%～66.03%,H2S去除率为10.63%～60.28%;蚯蚓粪各添加比例的NH3去除率为10.07%～50.75%,H2S去除率为13.95%～56.78%。同时,随着添加比例的提高,有效微生物EM、稻草和蚯蚓粪对NH3和H2S的去除率增大,达到奶牛粪堆肥中最大的保氮除臭效果时,EM的添加比例为3%、稻草的添加比例为30%、蚯蚓粪的添加比例为10%。     

污染底泥的原位钝化技术研究进展

底泥是湖泊重要的内源污染来源,关于底泥污染控制的研究近年来受到广泛重视。目前对底泥污染的控制技术主要包括原位处理技术和异位处理技术。原位处理技术主要包括钝化、覆盖、生物修复等。钝化技术是一种高效的湖泊内源污染控制技术,它通过抑制内源营养盐的释放来控制水体营养盐含量。文章综述了底泥原位钝化技术的研究及其应用情况;分析了原位钝化技术的特点及主要功能;介绍了常用底泥钝化剂的应用情况以及新型钝化剂的研究进展;并对原位钝化技术的未来发展进行了展望。     

Highly active mixed-phase TiO2 photocatalysts fabricated at low temperature and the correlation between phase composition and photocatalytic activity

The idea of varying volume ratio of water to ethanol in solvent was firstly employed to yield phase composition controllable mixedphase titanium dioxide (TiO2) photocatalysts via a low temperature solvothermal route at 353 K. It was found that anatase contents increase from 0 to 100% with increase of ethanol contents in solvent. The mixed-phase TiO2 with 60% anatase content exhibited the best photocatalytic activity in photodecomposing formaldehyde (FAD) under UV light irradiation, which increases by about ...     

The difficulties of systematic reviews

The need for robust evidence to support conservation actions has driven the adoption of systematic approaches to research synthesis in ecology. However, applying systematic review to complex or open questions remains challenging, and this task is becoming more difficult as the quantity of scientific literature increases. We drew on the science of linguistics for guidance as to why the process of identifying and sorting information during systematic review remains so labor intensive, and to provide potential solutions. Several linguistic properties of peer‐reviewed corpora—including nonrandom selection of review topics, small‐world properties of semantic networks, and spatiotemporal variation in word meaning—greatly increase the effort needed to complete the systematic review process. Conversely, the resolution of these semantic complexities is a common motivation for narrative reviews, but this process is rarely enacted with the rigor applied during linguistic analysis. Therefore, linguistics provides a unifying framework for understanding some key challenges of systematic review and highlights 2 useful directions for future research. First, in cases where semantic complexity generates barriers to synthesis, ecologists should consider drawing on existing methods—such as natural language processing or the construction of research thesauri and ontologies—that provide tools for mapping and resolving that complexity. These tools could help individual researchers classify research material in a more robust manner and provide valuable guidance for future researchers on that topic. Second, a linguistic perspective highlights that scientific writing is a rich resource worthy of detailed study, an observation that can sometimes be lost during the search for data during systematic review or meta‐analysis. For example, mapping semantic networks can reveal redundancy and complementarity among scientific concepts, leading to new insights and research questions. Consequently, wider adoption of linguistic approaches may facilitate improved rigor and richness in research synthesis.     

Mn/γ-Al2O3催化剂的制备及头孢合成废水的催化臭氧氧化法深度处理

对Mn/γ-Al₂O₃催化剂的制备条件及头孢合成废水的催化臭氧氧化法深度处理工艺条件进行了优化。实验结果表明：以Mn（NO₃）₂溶液为浸渍液，Mn/γ-Al₂O₃催化剂的最优制备条件为浸渍液浓度0.10 mol/L、浸渍时间9 h、焙烧温度400 ℃、焙烧时间2 h;在反应时间为30 min、废水pH为9.0、臭氧通量为4.6 mg/min、催化剂加入量为5 g/L的条件下，当进水COD、BOD₅、ρ（氨氮）和色度分别为220~250 mg/L，8~10 mg/L，10~12 mg/L和60~70倍时，出水COD、BOD₅、ρ（氨氮）和色度的平均去除率分别为53%，30%，33%和93%，出水水质满足GB 21904—2008《化学合成类制药工业水污染物排放标准》的要求。