农村污水处理中的主要难点与对策分析

农村污水的处理涉及建设与运营两方面的工作,具有专业性和复杂性的特点。本文先从污水收集系统建设、污水收集管网建设、污水处理技术及污水处理投入资金四个方面来分析论述农村污水处理中的主要难点,进而提出针对性的优化对策,最后论述了农村污水处理的未来探索思路与方向。     

定氮仪测定化肥中总氮含量不确定度评价

对使用凯氏定氮仪测定肥料中总氮含量方法进行不确定度评定,分析该测定方法中不确定度的来源,通过数字模型对各不确定度分量进行评定,并给出了结果的报告形式。     

Influences of graphene oxide support on the electrochemical performances of graphene oxide-MnO2 nanocomposites

MnO₂ supported on graphene oxide (GO) made from different graphite materials has been synthesized and further investigated as electrode materials for supercapacitors. The structure and morphology of MnO₂-GO nanocomposites are characterized by X-ray diffraction, X-ray photoemission spectroscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and Nitrogen adsorption-desorption. As demonstrated, the GO fabricated from commercial expanded graphite (denoted as GO(1)) possesses more functional groups and larger interplane gap compared to the GO from commercial graphite powder (denoted as GO(2)). The surface area and functionalities of GO have significant effects on the morphology and electrochemical activity of MnO₂, which lead to the fact that the loading amount of MnO₂ on GO(1) is much higher than that on GO(2). Elemental analysis performed via inductively coupled plasma optical emission spectroscopy confirmed higher amounts of MnO₂ loading on GO(1). As the electrode of supercapacitor, MnO₂-GO(1) nanocomposites show larger capacitance (307.7 F g^-1) and better electrochemical activity than MnO₂-GO(2) possibly due to the high loading, good uniformity, and homogeneous distribution of MnO₂ on GO(1) support.     

Human Adipose-Derived Mesenchymal Progenitor Cells Engraft into Rabbit Articular Cartilage

Mesenchymal stem cells (MSCs) are known to have the potential for articular cartilage regeneration, and are suggested for the treatment of osteoarthritis (OA). Here, we investigated whether intra-articular injection of xenogeneic human adipose-derived mesenchymal progenitor cells (haMPCs) promoted articular cartilage repair in rabbit OA model and engrafted into rabbit articular cartilage. The haMPCs were cultured in vitro, and phenotypes and differentiation characteristics of cells were evaluated. OA was induced surgically by anterior cruciate ligament transection (ACLT) and medical meniscectomy of knee joints. At six weeks following surgery, hyaluronic acid (HA) or haMPCs was injected into the knee joints, the contralateral knee served as normal control. All animals were sacrificed at the 16th week post-surgery. Assessments were carried out by macroscopic examination, hematoxylin/eosin (HE) and Safranin-O/Fast green stainings and immunohistochemistry. The data showed that haMPC treatment promoted cartilage repair. Signals of human mitochondrial can be directly detected in haMPC treated cartilage. The haMPCs expressed human leukocyte antigen I (HLA-I) but not HLA-II-DR in vivo. These results suggest that intra-articular injection of haMPCs promotes regeneration of articular cartilage in rabbit OA model, and support the notion that MPCs are transplantable between HLA-incompatible individuals.     

从废玻璃渣中提取氧化铈的研究

为了实现玻璃生产过程中废玻璃的综合利用,得到经济价值高、加工成本低的氧化铈。以某企业的废玻璃为原料,经稀盐酸预处理后溶解于浓盐酸中提取氧化铈。分别研究了稀盐酸的浓度和加入量、浓盐酸的加入量、水浴时间和温度等因素对氧化铈产率的影响,并得出了最佳提取条件:稀盐酸浓度为2 mol/L、稀盐酸加入量为100 mL、浓盐酸加入量为250 mL、水浴时间为2 h、水浴温度为95℃。     

Sol-gel-derived hydroxyapatite-carbon nanotube/titania coatings on titanium substrates

In this paper, hydroxyapatite-carbon nanotube/titania (HA-CNT/TiO(2)) double layer coatings were successfully developed on titanium (Ti) substrates intended for biomedical applications. A TiO(2) coating was firstly developed by anodization to improve bonding between HA and Ti, and then the layer of HA and CNTs was coated on the surface by the sol-gel process to improve the biocompatibility and mechanical properties of Ti. The surfaces of double layer coatings were uniform and crack-free with a thickness of about 7 μm. The bonding strength of the HA-CNT/TiO(2) coating was higher than that of the pure HA and HA-CNT coatings. Additionally, in vitro cell experiments showed that CNTs promoted the adhesion of preosteoblasts on the HA-CNT/TiO(2) double layer coatings. These unique surfaces combined with the osteoconductive properties of HA exhibited the excellent mechanical properties of CNTs. Therefore, the developed HA-CNT/TiO(2) coatings on Ti substrates might be a promising material for bone replacement.     

端氨基聚脲聚氨酯环氧树脂体系的固化反应及粘接性能

本文采用DTA和FT-IR研究了端氨基聚脲聚氨酯固化环氧树脂的反应特性,考察了被粘表面状态、偶联剂和促进剂、填料等对剪切强度性能的影响。并对该粘合剂耐化学腐蚀性进行了试验,说明具有好的耐腐蚀性。     

基于云模型的巷道顶板稳定性模糊评价与应用

采场巷道岩体结构复杂,局部应力高度集中,顶板失稳破坏现象时有发生,对井下工作人员及设备造成了很大威胁,因此开展巷道顶板的稳定性评价研究十分必要.选取巷道结构特征因素、岩体质量因素、工程环境因素等评价指标,构建了具有模糊性、客观性的稳定性评价指标体系;利用云模型代替隶属函数,构建了基于云模型的巷道顶板稳定性模糊评价模型....     

集成电路制备中化学机械全局平面化(CMP)后的表面清洗技术

论述了集成电路制备中CMP过程带来污染的重大危害,介绍了目前CMP后清洗所面临的两大新挑战,同时对CMP后清洗的现状做出了分析,提出了存在的问题,并且对未来清洗的方向进行了展望。     

Influence of Metal (Au, Ag) Micro-Grid on the Photocatalytic Activity of TiO2 Film

In this paper, we prepared TiO₂ thin film with the surface modified by a connected Au micro-grid via a microsphere lithography strategy, and the modified films show higher photocatalytic activity than the pure TiO₂ film. The photocatalytic activity improved as Au loading increased, obtaining the best performance at a certain loading amount, and then decreased at higher loading amount. This behavior, not observed in TiO₂ films modified with Ag micro-grid, can be attributed to the relationship between the energetic positions and the metal clusters size.