Ni18Co9Mo5在湿热海洋和亚湿热酸雨大气环境下的性能变化规律研究

目的 研究Ni18Co9Mo5在湿热海洋环境(永兴)和亚湿热酸雨环境(重庆)下的腐蚀行为和力学性能规律。方法 通过金属粉末注塑成形方法制备Ni18Co9Mo5样品,采用力学试验机、X射线衍射分析仪、扫描电子显微镜、能谱分析仪、金相显微镜对Ni18Co9Mo5在永兴和重庆典型大气环境下暴露试验18个月的性能变化规律进行研究。结果 Ni18Co9Mo5样品的耐蚀性较差,在海洋环境和亚湿热酸雨下暴露2个月即出现明显的腐蚀现象,在平均相对湿度达到临界湿度(80%)基础上,腐蚀介质SO₂(亚湿热酸雨环境)和Cl^–(海洋环境)对Ni18Co9Mo5金属材料的早期腐蚀具有加剧作用。Ni18Co9Mo5在永兴试验18个月后,腐蚀产物较为疏松,且样品内外腐蚀区域均存在明显裂纹,其抗拉强度和冲击能量分别下降43%和60%左右;在重庆试验18个月后,其抗拉强度下降15%,冲击能量整体变化不明显。湿热海洋环境中侵蚀性强的Cl–导致Ni18Co9Mo5发生点蚀,甚至裂纹萌生及扩展,加剧了样品基体的腐蚀,有效承载面积减小及裂纹导致力学性能明显下降。结论 Ni18Co9M...     

Variability and predictability of sea-level extremes in the Hawaiian and U.S.-Trust Islands—a knowledge base for coastal hazards management

The objective of this study is to provide an improved climatology of sea level extremes on seasonal and long-term time scales for Hawaii and the U.S-Trust islands. Observations revealed that the Hawaiian and U.S.-Trust islands, by and large, display a strong annual cycle. For estimating the statistics of return period, the three-parameter generalized extreme value (GEV) distribution is fitted using the method of L-moments. In the context of extremes (20- to 100-year return periods), the deviations in most of the Hawaiian Islands (except at Nawiliwili and Hilo) displayed a moderate sea-level rise (i.e., close to 200 mm), but the deviations in the U.S.-Trust islands displayed a considerably higher rise (i.e., more than 300 mm) in some seasons due to typhoon-related storm surges. This rise may cause damage to roads, harbors, and unstable sandy beaches. Correlations between the El Niño-Southern Oscillation (ENSO) climate cycle and the variability of seasonal sea level have been investigated. Results show that correlation for the station located west of the International Date Line (DL) is strong, but it is moderate or even weaker for stations east of the DL. The skill of SST-based Canonical Correlation Analyses (CCA) forecasts was found to be weak to moderate (0.4–0.6 for Honolulu, Kahului, Hilo, and Wake, and 0.3 or below for Kahului, Mokuoloe, and Johnston). Finally, these findings are synthesized for evaluating the potential implications of sea level variability in these islands.     

火焰原子吸收光谱法测定苏州开发区26种蔬菜中铜锌铁锰镍

用火焰原子吸收光谱法测定了苏州开发区26种蔬菜中的铜、锌、铁、锰和镍的含量。蔬菜样品用硝酸高氯酸混合酸进行消解。4次测定值的相对标准差<5%,加标回收率在92%～107%之间。26种蔬菜中铜、锌、铁、锰、镍的含量基本均在世贸组织规定的范围内。     

镍对活性污泥生物除磷的影响及其机理

以实际生活污水为研究对象,在序批式活性污泥反应器中探究了Ni2+对活性污泥形态及生物除磷性能的影响。实验结果表明,Ni2+能够抑制生物除磷,当Ni2+质量浓度由0 mg/L增加至10.0 mg/L时,PO43--P去除率由93%下降至12%。机理研究结果表明：Ni2+能抑制聚磷微生物的厌氧释磷和好氧吸磷,并能抑制内聚物聚羟基烷酸酯（PHA）的合成;当Ni2+质量浓度为10.0 mg/L时,PHA的最大含量仅为2.4 mmol/g （以单位质量挥发性悬浮物所含PHA中C的物质的量计）,远低于空白组中PHA的含量。此外,Ni2+还对微生物群落的组成产生影响,并促进活性污泥中聚糖微生物的增殖。     

Improving Community-Based Conservation Near Protected Areas: The Importance of Development Variables

Community-based conservation projects implemented in conjunction with protected area management often struggle to meet expectations. This article argues that outcomes will improve if project leaders pay closer attention to four development indicators—rights, capacity, governance, and revenue—that are often taken for granted or considered beyond the scope of local conservation projects. I make the case for focusing on these variables in four steps. First, I distinguish community-based conservation linked to protected area management from community-based institutions studied by scholars of the commons. Second, I draw on the theory and practice of international development to highlight the central relevance of the variables highlighted in this article to development projects at all levels. Third, I discuss the four variables in some detail, considering problems of definition and measurement and reviewing possible interactions among them. Fourth, to illustrate the influence of the variables in particular cases, I review outcomes from community-based conservation projects implemented near protected areas in El Salvador and Zimbabwe.     

Pd/Fe和Ni/Fe二元金属去除水体中莠去津的比较

对比Ni/Fe和Pd/Fe二元金属对莠去津的催化降解特性.结果表明,在相同反应条件下(C0=20.0mg·l-1,pH=3.0,金属添加量为1.0g),与Fe0相比,Pd/Fe对莠去津表现出比Ni/Fe更加明显的催化脱氯效果,反应75min,Fe0对莠去津的脱氯效率为7.09%,Ni/Fe达到99.11%,而Pd/Fe反应30min就能够100%还原莠去津.通过SEM,XRS和BET-N2测试,Pd以无定形状态分布在Fe0的表面,有利于比表面积的增大,Ni/Fe和Pd/Fe的比表面积分别为11.671和16.94m2·g-1;而且Pd/Fe对H2有非常强的吸附能力,1cm3的Pd在常温下能够吸附1000ml H2,最高能够达到2800ml.体系pH值对Ni/Fe和Pd/Fe催化莠去津的影响非常大,pH=2.0时, Pd/Fe反应15min能够100%降解莠去津;pH=3.0时,30min达到完全降解;pH=4.0和未调节pH条件下,75min的脱氯效率只有82.55%和46.5%.     

TiO2/Ni PECO体系降解DMP的动力学和光电协同作用研究

以采用微波辅助法制备的TiO₂/Ni光电极为阳极,纤维状石墨毡材料(graphite felt,GF)为阴极,饱和甘汞电极(saturated calomel electrode, SCE)为参比电极建立TiO₂/Ni 光电催化氧化（PECO）体系。以邻苯二甲酸二甲酯（dimethy phthalate,DMP）为目标物,研究其光电催化降解反应动力学和光电协同作用。结果显示：DMP的降解符合拟一级动力学规律;当DMP初始浓度一定时,影响DMP光电催化降解速率的因素由强到弱依次为：催化剂有效面积,紫外光强度,曝氧速率,外加偏转电压等。实验证明本体系中光电之间具有协同作用。     

TiO_2/NiPECO体系降解DMP的动力学和光电协同作用研究

以采用微波辅助法制备的TiO2/Ni光电极为阳极,纤维状石墨毡材料(graphite felt,GF)为阴极,饱和甘汞电极(saturated calomel electrode,SCE)为参比电极建立TiO2/Ni光电催化氧化(PECO)体系.以邻苯二甲酸二甲酯(dimethyphthalate,DMP)为目标物,研究其光电催化降解反应动力学和光电协同作用.结果显示:DMP的降解符合拟一级动力学规律;当DMP初始浓度一定时,影响DMP光电催化降解速率的因素由强到弱依次为:催化剂有效面积,紫外光强度,曝氧速率,外加偏转电压等.实验证明本体系中光电之间具有协同作用.     

Institutional, policy and farmer responses to drought: El Niño events and rice in the Philippines

Droughts are common recurring natural hazards in Asia, and El Niño events are particularly severe in the Philippines. This paper explores responses by farm households, irrigation system managers, and macro policymakers in the Philippines to El Niño. In response to the large 1997–98 El Niño, farmers in one major irrigation system significantly diversified their economic activities, hut the drought was so acute that many of these activities were not successful. Communication between meteorologists and irrigation system managers is strong, and irrigation system managers are aware of El Niño events in advance. Communication between irrigation system managers and farmer irrigation associations is also strong, and together they have developed response options that attempt to augment supplies of and more efficiently allocate scarce water. Water pricing is not used, however, and lack of cooperation among farmers results in sub-optimal outcomes. Macro-level policy responses in terms of rice imports and buffer stock management to protect poor consumers have improved substantially over time.     

The Influence of the Pacific Decadal Oscillation on Annual Floods in the Rivers of Western Canada

We analyzed annual peak flow series from 127 naturally flowing or naturalized streamflow gauges across western Canada to examine the impact of the Pacific Decadal Oscillation (PDO) on annual flood risk, which has been previously unexamined in detail. Using Spearman's rank correlation ρ and permutation tests on quantile‐quantile plots, we show that higher magnitude floods are more likely during the negative phase of the PDO than during the positive phase (shown at 38% of the stations by Spearman's rank correlations and at 51% of the stations according to the permutation tests). Flood frequency analysis (FFA) stratified according to PDO phase suggests that higher magnitude floods may also occur more frequently during the negative PDO phase than during the positive phase. Our results hold throughout much of this region, with the upper Fraser River Basin, the Columbia River Basin, and the North Saskatchewan River Basin particularly subject to this effect. Our results add to other researchers' work questioning the wholesale validity of the key assumption in FFA that the annual peak flow series at a site is independently and identically distributed. Hence, knowledge of large‐scale climate state should be considered prior to the design and construction of infrastructure.