济南大气臭氧浓度变化规律

利用近2a济南市区近地面大气O₃浓度的观测数据,分析了O₃浓度的分布特征及时间变化规律.结果表明,济南市区O₃浓度以1a为周期呈明显的波动变化特征,城市光化学污染较重;1d当中O₃浓度呈明显的单峰型变化,一般在午后达到最高值,而日出时分出现最低值;春季和夏季O₃浓度高于秋季和冬季,而夏季和秋季O₃浓度的日内变化幅度明显高于春季和冬季;受人们活动规律的影响,周末O₃浓度的日内变化规律与平日有所不同.     

Effect of preparation method of noble metal supported catalyts on formaldehyde oxidation at room temperature: Gas or liquid phase reduction

Formaldehyde (HCHO) is toxic to the human body and is one of the main threats to the indoor air quality (IAQ). As such, the removal of HCHO is imperative to improving the IAQ, whereby the most useful method to effectively remove HCHO at room temperature is catalytic oxidation. This review discusses catalysts for HCHO room-temperature oxidation, which are categorized according to their preparation methods, i.e., gas-phase reduction and liquid-phase reduction methods. The HCHO oxidation performances, structural features, and reaction mechanisms of the different catalysts are discussed, and directions for future research on catalytic oxidation are reviewed.     

A numerical simulation model of cyclic hardening behavior of AC4C-T6 for LNG cargo pump using finite element analysis

This paper is concerned with the evaluation of cyclic hardening models within the stress–strain behavior of aluminum alloy AC4C-T6 that can be used to LNG cargo pump operating in cryogenic temperature. To insure the strength assessment of LNG cargo pump, material model of cyclic hardening and plasticity for aluminum alloy AC4C-T6 is investigated through FEA (Finite Element Analysis) with various hardening options including linear and non-linear hardening, isotropic and kinematic hardening, and combined hardening model. Monotonic tensile and cyclic tensile experiments for AC4C-T6 alloy were performed at room temperature and temperature of ?165 °C. Parameters of each hardening model are obtained from the experimental data; thus five hardening models are numerically simulated thereafter. Appropriate hardening models which describe the cyclic stress–strain relationship are investigated through the simulations of cyclic hardening behavior by FEA. In order to verify the predicted behavior of cyclic hardening obtained by FEA, the results of FEA and those measured by experiments are compared.     

无机阴离子对镉、铅解吸特性的影响

土壤中重金属的解吸直接影响重金属在环境中的形态转化和植物有效性.而地表水环境及土壤中的无机阴离子能与重金属离子络合,影响重金属在环境中的迁移和作物的吸收.因此,有关无机阴离子对重金属解吸特性影响的研究,将有利于了解重金属的吸附-解吸机制及其控制措施.文章以我国东北地区草甸棕壤作为研究对象,采用静态解吸实验研究无机阴离子(C1-、SO42-、F-)对土壤中镉、铅的解吸行为的影响.结果表明,土壤中镉、铅的解吸率与无机阴离子类型、浓度密切相关;随着解吸液中无机阴离子(C1-、SO42-、F-)浓度的增大,土壤镉、铅的解吸率随之提高.C1-、SO42-、F-这3种无机阴离子对解吸土壤中镉的影响力顺序是:C1- > SO42- > F-;对解吸土壤中铅的影响力顺序是:SO42- >C1- > F-.     

森林自然保护地生态旅游资源研究进展

旅游资源的评价、保护与开发模式研究是生态旅游研究领域的重要内容,而森林自然保护地是一类重要的生态旅游区.根据我国自然保护地的实际情况,参考国外自然保护地的定义与分类方式,可认为我国的森林自然保护地主要应主要包括森林生态系统类型自然保护区、森林公园及公益林场三种类型;森林自然保护地的生态旅游资源评价研究主要集中在两方面:一是单纯地从经济学角度对旅游资源游憩价值进行货币化评价与核算,二是从保护生物学和生态学角度对资源的可开发性进行评价,其侧重在于找到保护与开发的的科学平衡点;在森林自然保护地旅游资源的开发模式研究上,必须正确处理开发与保护的关系,把保护放在第一位,坚持"三大效益"兼顾的原则,才能实现森林生态旅游资源开发与保护的良性循环.由于经营目的和保护级别差异,自然保护区、森林公园及公益林场的生态旅游研究与实践尚存在发展不均衡、功能不突出等问题,随着生态旅游事业的深入发展,一些非热点和低等级的森林自然保护地在生态旅游理论研究与开发实践中将会发挥越来越重要的作用.     

城市污水处理厂好氧颗粒污泥的特性

对城市污水处理厂曝气池中筛选出的好氧颗粒污泥进行了分析.结果表明,这些颗粒污泥的直径主要在0.2～0.8 mm范围;平均圆度为1.29;沉淀速率约在10～42 m h-1之间;比耗氧速率(SOUR)为14.2～18.9 mg g-1h-1,小于活性污泥;挥发性物质占总固体的量与活性污泥基本相似.这些颗粒污泥占污泥总量的0.1%～0.5%.颗粒污泥的激光共聚焦扫描显微镜(CLSM)图像显示:颗粒污泥内部几乎都由胞外聚合物(EPS)组成;细菌主要分布在颗粒污泥表面至100μm厚度区域,少部分分布在100～400μm厚度区域.     

论民国时期河南灾荒的社会成因

民国年间河南灾荒现象异常突出,虽与当时整体气候背景及河南特殊的地理特征相关,但灾荒背后的社会原因更应引起我们的关注。其主要表现为:一、社会经济乏力,百姓抗灾能力低;二、政治腐败,体现在政府的赋税名目繁多、政府官员失职渎职以及挪用、贪污河防公款等几个方面;三、战争与灾荒;四、帝国主义列强对中国的残酷掠夺。     

小清河水中沉积物与铅离子吸附等温线的研究

运用界面分极离子/配位子交换原理和方法研究了小清河水中沉积物对Pb^2 的交换吸附等温线以及赖氨酸对吸附作用的影响。研究结果得出等温线具有1个“拐点”2个“平台”。用分级离子交换等温式求出平衡常数k1和k2,当低浓度的氨基酸存在时,对铅与沉积物的交换吸附起促进作用。     

Formation and transformation of schwertmannite in the classic Fenton process

The massive amount of sludge generated by the classic Fenton process, which has often been hypothesized to consist of ferric hydroxide, remains a major obstacle to its large-scale application. Therefore, reutilization of Fenton sludge has recently gained more attention.Understanding the formation, transformation, and properties of Fenton sludge combined with the stages of the Fenton reaction is pivotal, but not well illustrated yet. In this study,SEM-EDS, FT-IR, XRD, and XPS were applied to study the morphology, crystallinity,elemental composition, and valence state of Fenton sludge. The authors report that schwertmannite and 2-line ferrihydrite were generated and transformed in the oxidation phase and the neutralization phase of the Fenton process. SO_4~(2-) in the solution decreased by8.7%–26.0% at different molar ratios of Fe(II) to H_2 O_2; meanwhile, iron ion precipitated completely at pH 3.70 with the formation of schwertmannite containing sulfate groups in the Fenton sludge. The structural sulfate(Fe-SO_4) in schwertmannite was released from the precipitate with the addition of OH-, and the production of Fenton sludge decreased with increasing pH when pH 3.70. Goethite was found to form when the final p H was adjusted to 12 or at a reaction temperature of 80°C. Moreover, the possible thermal transformation to goethite and hematite indicated that Fenton sludge can be reused as a raw material for synthesizing more stable iron(hydro)oxides. The results provide useful insights into the formation and transformation of Fenton sludge, with implications for regulating the crystal type of Fenton sludge for further reuse.     

内蒙古生物质热电联产的效益研究

本文从生物质热电联产的必要性作为切入点,从经济、社会、生态效益三个方面分析了内蒙古发展生物质能热电联产的综合效益.