对聚合物/蒙脱土纳米复合注浆材料的初步研究

聚合物/蒙脱土(MMT)纳米复合材料,是现在世界上投入研究探索最多、最受人们关注的复合材料之一。在我国,蒙脱土资源非常丰富,蒙脱土独有的特点,使其成为制备新型复合材料的最重要的一类无机物。蒙脱土与聚合物的插层复合研究在塑料和橡胶领域己取得了很多成果,但在化学注浆方面却是一片空白。本篇论文只是作了一些探索性研究,介绍了聚合物/蒙脱土纳米复合注浆材料的概念;用插层法制备聚合物/蒙脱土复合材料浆液。文章最后对将来研究工作进行了一些展望。     

坡缕石/聚合物纳米复合材料的研究进展

坡缕石是一种层链状硅酸盐矿物。具有独特的纳米棒晶结构。是一种很有潜力的一维纳米增强材料。综述了坡缕石／聚合物纳米复合材料的研究进展，所涉及的聚合物包括丁苯橡胶、丁腈橡胶、聚乙烯、聚氯乙烯、聚苯乙烯、聚丙烯、环氧树脂、双马来酰亚胺树脂(BMI)和聚酰胺等。制备方法包括机械共混法、乳液共混共凝法、溶液共混法、熔融复合法和原位聚合法。研究表明。坡缕石纳米棒晶的分散在制备纳米复合材料的过程中非常重要，而超声波分散是目前最经济有效的方法。还简要论述了对甘肃某地坡缕石提纯并应用于丁腈橡胶制备纳米复合材料的研究。最后展望了坡缕石／聚合物纳米复合材料的应用前景。并对以后需要深入研究的方向进行了分析。     

混合构型低轨卫星增强GPS精密单点定位性能分析

低轨卫星具有信号强度高、运动速度快的特点,引入低轨卫星可改善矿区、城市、峡谷等复杂环境下GNSS接收机观测数据质量差、定位精度较低的问题。采用混合构型低轨星座进行定位增强,利用仿真低轨卫星数据对不同数量、不同构型的低轨卫星在不同截止高度角情况下增强GPS PPP性能进行分析。结果表明：1)GPS联合LEO定位可以显著增加可见卫星数,降低PDOP值。2)在截止高度角为30°时,低轨卫星可显著提高GPS定位性能,改善定位精度并减少收敛时间。其中,主子星座(96+9)联合GPS定位与同卫星数低轨卫星相比,在提升子星座覆盖区域测站(HKSL)N、U方向定位精度及减少收敛时间方面效果更好。     

蓝田膨润土的发现及其物化性能研究

蓝田膨润土系笔者首次发现,本文初步研究了该膨润土的成分、属性、物化性能及其地质特征等。经研究认为,蓝田膨润土属钙镁基土,是比较少见的类型;除含大量蒙脱石外,还含一定数量的有益组分——凹凸棒石和高岭石;物化性能尚好;沉积成因,具有一定的规模和应用价值,建议应进一步进行普查找矿和应用开发研究。     

空气氛围制备核壳纳米零价铁实验研究及其对地下水原位修复的启示意义

运用纳米零价铁进行地下水污染原位处理是近年新发展的环境修复新技术,传统合成纳米零价铁一般多采用无氧条件(通氮气保护)液相法,操作繁琐,不适合批量生产。为了达到纳米零价铁液相法大规模制备和便于现场应用的目的,通过对比传统方法(通氮气除氧),提出在空气氛围中(有氧)制备纳米零价铁。透射电镜和X射线衍射分析表明,空气中直接制备的纳米零价铁Fe@Fe₂O₃有明显核壳结构,粒径40~100 nm,内核零价铁,外壳氧化铁厚4~5 nm。纳米铁降解水中甲基橙和去除六价铬的实验表明,空气氛围中制备的纳米铁反应活性最好,10 min内0.4 g/L (RO) Fe@Fe₂O₃能够把200 mg/L甲基橙降解98.6%,30 min内0.2 g/L(RO) Fe@Fe₂O₃能够把20 mg/L六价铬去除84.7%。因此,省略了氮气保护环节,成功合成核壳结构纳米零价铁,这有利于现场应用时现配现用,并降低运输保管纳米铁的成本和风险,对开展原位现场污染修复具有启示和应用价值。      

制备工艺对低温烧结Ni-Cu-Zn铁氧体/BaTiO_3复合材料性能的影响

采用2种复合工艺流程在900°C和950°C制备了适用于低温共烧陶瓷(LTCC)工艺的Ni-Cu-Zn铁氧体/BaTiO3复合材料。对比研究了不同工艺流程下,烧结温度及助剂用量变化对复合体系烧结性能和电磁性能的影响。900°C烧结时,在铁氧体预烧前添加BaTiO3(工艺流程Ⅱ)制备的复合材料比在铁氧体预烧后添加BaTiO3(工艺流程Ⅰ)制备的复合材料有更高的烧结密度(5.40g/cm3)和Snoek乘积(5.56GHz);950°C烧结时,工艺流程Ⅱ制备的复合材料的介电性能优于工艺流程Ⅰ制备的。     

基于敏感位置哈希索引的音频检索

基于内容音频检索的关键问题包括音频特征提取及特征检索算法.将LSH(Locality Sensitive Hashing)索引算法应用于基于内容的音频检索系统中,与传统的索引方法相比,该算法具有复杂度比较低、支持非常高的维数等特点.实验结果表明,将索引算法应用于基于内容的音频检索系统中,其性能优于传统的索引方法.     

广西宁明膨润土矿石特征及应用试验研究

文章介绍了宁明膨润土矿石特征及其应用试验,指出矿石中蒙脱石含量偏低,矿物粒度微细,矿石属性较齐全,并具有优异的膨胀分散性能.初步应用试验结果表明,在铸造型砂和冶金球团应用效果良好;采用湿法提纯,能有效提高原矿的蒙脱石含量,为今后开发高附加值的深加工产品提供了途径.     

超高相对分子质量聚乙烯纤维表面改性的方法、应用以及性能表征

ＵＨＭＷ ＰＥ纤维具有超高强高模的独特力学性能 ,并具有密度小、耐腐蚀、耐冲击等优异性能 ,在特种材料和复合材料领域显示出极好的应用前景。但由于其分子链由亚甲基组成 ,不带有极性基团 ,因而熔点较低 ,表面能低 ,粘结性和抗蠕变性能较差 ,表面呈化学惰性 ,在很大程度上限制了应用范围 ,因此对其进行表面改性处理是一项很重要的研究工作。1　ＵＨＭＷ ＰＥ纤维的表面改性方法高聚物材料表面改性的方法有许多 ,按性质可分为三类 :物理改性、化学改性和本体改性。其中物理改性的方法可以分为两大类 :第一类改性方法使聚合物的表面层同时…     

陕南膨胀土判别与分类的模糊综合评判

用模糊数学方法,选用与膨胀土胀缩特性有关的指标:粘粒含量(m_(0.005))、液限(W_L)、液性指数(I_L)、线缩率(e_u)、自由膨胀率(δ_(ef)),对陕南地区膨胀土进行了模糊综合评判。其结果可分为3类:一类是灰白、灰绿色强膨胀潜势膨胀土;二类是三级以上阶地上黄褐-棕红色的中等膨胀潜势的膨胀土;三类是二级阶地上褐黄-黄褐色弱膨胀潜势的膨胀土。     

纳微米聚合物微球的水化膨胀封堵性能

为改善聚合物微球的深度调剖效果,利用蒸馏沉淀聚合法制备纳微米聚合物微球,并利用激光粒度分析仪、微孔滤膜装置和驱替装置对纳微米聚合物微球的粒径、水化膨胀能力和变形封堵能力进行测试分析.结果表明:纳微米聚合物微球为较规则均匀的球形,粒径分布集中,具有良好的水化膨胀性能;随着盐矿化度增大,纳微米聚合物微球膨胀性能变差;随着温度升高,微球的膨胀性能变强;在氯化钙和氯化镁水型中,微球膨胀性能变差;在酸性和碱性环境中,微球膨胀性能变差;随着水化时间增长,微球的封堵性能和变形能力逐渐增强,对孔道产生有效封堵的同时又能变形通过孔道,在渗透率较低的岩心中具有更好的深度调剖效果.     

A debris-flow impact pressure model combining material characteristics and flow dynamic parameters

Impact force is a crucial factor to be considered in debris-resisting structure design. The impact of debris flow against a structural barrier depends not only on the flow dynamics but also on the barrier material. Based on the structural vibration equation and energy conservation law, a simple model for calculating debris-flow impact pressure is proposed, which includes the mechanical impedance of the material, debris-flow velocity and Froude number. Twenty-five impact tests have been conducted using different kinds of materials: steel, black granite, white granite, marble and polyvinyl chloride (PVC) board, and the ratio of the maximum impact time to the vibration period of the structure is determined for the model. It is found that the ratio’s square root shows a linear relationship with the material solid Froude number. This indicates that the impedance of the structures plays an important role in the flow-barrier interaction. Moreover, the debrisflow impact force is found to decrease with the travel time of the elastic stress wave though the structures.     

鲁西地区矽卡岩型铜金矿He—Ar同位素测定及其地质意义——以沂南地区铜井式铜金矿为例

铜井式铜金矿(包括铜井铜金矿、金场铜金矿)是鲁西地区发现和开采最早、矿化最普遍的矽卡岩型铜金矿。该文通过矿床的He-Ar同位素测试分析,并结合前人的H,O,S,C稳定同位素分析和年代学测试结果,对铜井式铜金矿成因及成矿机制进行探讨。研究认为,铜井式金矿主要形成于燕山晚期(128~121Ma),黄铁矿中流体包裹体的~(3 )He/~(4 )He值为0.112 9~0.120 9R/Ra,高于地壳物质值,低于典型地幔物质值;~(40 )Ar/~(36 )Ar=364.1~458.0,高于大气值,低于地幔值,成矿流体中存在来源于地壳的放射成因Ar;~(4 )He/~(40 )Ar=1.16~3.433,平均2.296 5,略高于地幔值(1.36~2.23),低于典型地壳值(6.4),表明成矿流体中存在地幔He,Ar;同时有地壳He,Ar加入。综上认为,矿床成矿物质和流体具有深源特征,应来自地幔或下地壳,金成矿主要是与燕山晚期浅成—超浅成中酸性侵入岩有关,这些侵入体在侵位过程中与古生代碳酸盐岩地层发生接触交代作用,形成矽卡岩型铜金矿床。     

Development of the nano-composite cement: Application in regulating grouting in complex ground conditions

Improvement of the fluidity and setting time of grouting materials has been recognized as an effective approach of seepage prevention in foundation works, and it is quite common to be used for handling severe leakages in complex ground conditions, such as loose, broken and fully fissured stratum. For the purposed of better meeting the engineering requirements, experimental studies were conducted in this study with focus on the nanocomposite grouting materials and the related controlled grouting technology. As compared with the commonly used silicate-sulpho-aluminate composite cement, which is characterized by relatively poor rheological property, quick setting time and low strength, the most suitable nano-material with proper reactants were selected intentionally to improve the mentioned attributes of composite cement. Due to the setting time and strength of the targeted cement slurry behaving with poor performance of harmonization to engineering construction problems, hydration synergistic effect of these composites were investigated in our experiments. Results showed that the properties of grouting materials, including initial fluidity, setting time, ideal right-angle thickening, and early strength and late strength were sufficient to produce an expected grouting application. It is therefore advocated that the refined grouting material could provide a better solution to fix grouting problems in complex ground cementing operations.     

Using LIDAR and ground truth for landslide recognition and characterization of geotechnical and morphological parameters in sedimentary rocks,a case study in Northern Bavaria (Germany)

The use of LIDAR-derived shaded relief maps led to the identification of all potential landslide areas in a hilly region in Northern Bavaria (1590 km²), Germany. Every possible structure was investigated by field investigation which resulted in a detailed database of 1002 landslides within the study area. The analysis of geological, lithological, topographical and morphological properties (spatial ratio, lithological and geological setting, length/width distribution, material properties and slope angle) revealed characteristic appearances of the landslides and possible relationships between different aspects. Strong relations between the lithological setting, spatial ratio of the mapped landslides and distribution of slope angle could be observed. This study shows the value of high-resolution shaded relief maps for detecting and mapping landslides in a large area with comparatively little work and time in comparison to the traditional approach to mapping. It reveals that many landslides were not known before. Landslides are much more common in Northern Bavaria and have a higher influence on the denudation rate of the Franconian Alb than expected before.     

北山盆地群砂岩储层特征及分类评价

北山盆地群侏罗系和下白垩统砂岩储层主要属长石岩屑砂岩和岩屑长石砂岩,其次为岩屑砂岩,成分和结构成熟度均较低;储层孔隙类型以次生孔隙为主,孔隙结构及物性总体较差。储层分类评价及综合分析表明,中侏罗统储层属较有利储层,在北山盆地群具有较重要的储集意义。     

Study on Al-Zn-In Alloy as Sacrificial Anodes in Seawater Environment

Electrochemical properties including conventional electrochemical properties: open circuit potential, polarization potential, electrochemical capacity, morphology of surface dissolution, and the initial polarization properties of Al-Zn-In-Mg-Ti and Al-Zn-In-Si sacrificial anodes are investigated in the sea. The curves of anode output current and work potential with time, the impact of area ratio of cathode to anode on anode output current is discussed, and the initial polarization properties are investigated with cyclic voltammetry(CV) finally. The results show that for the two anodes, the current efficiency got in the sea environment is higher than the data of the 4-day-accelerated test in laboratory and the corrosion morphology is more uniform in the sea. With the same exposed area, the current efficiency of Al-Zn-In-Mg-Ti anode is higher than that of Al-Zn-In-Si in the sea. For both anodes, the current efficiency becomes larger with the increase of the area ratio of cathode to anode. The two anodes can output larger current in strong polarization state. The situation is consistent with the results that small area anode released higher current in the sea trial. The difference rests with that Al-Zn-In-Mg-Ti anode output far greater current than that of the Al-Zn-In-Si under the same polarization potential. The initial polarization property of the Al-Zn-In-Mg-Ti anode is better than Al-Zn-In-Si anode.     

Preparation and characterization of magnetic resin made from chitosan and cerium

In this study,the water-based ferromagnetic fluid and magnetic resin made from chitosan and cerium complex(MRCCC) were successfully prepared by using the chemical co-precipitation technique and by the reversed-phase suspension cross-linking polymerization.MRCCC presented uniform and narrow particle size distribution as determined by the Laser Particles Sizer.The Inductively Coupled Plasma-Atomic Emission Spectrometry(ICP-AES),Fourier transform infrared spectroscopy(FT-IR),differential scanning calorimetry(DSC)and X-ray powder diffraction(XRD)study demonstrated that there were iron and cerium existing in MRCCC.The movement of MRCCC under magnetic field proved its magnetic property.The swelling kinetics in water or solutions with different pH indicated that MRCCC could be applied in solutions with pH greater than 1.0.The ferromagnetic fluid particles were stable in MRCCC soaked in solutions with pH >2.0.In view of these results,MRCCC can be used as material for separation,clarification,adsorption,sustained release and hydrolysis activity.     

Modification of HDPE filling with pelagic clay

In order to improve the properties of HDPE, the authors used the method of suspended diffusion for purification the pelagic clay, used silane coupling agent to increase its organic activation, and prepared the composites of organic pelagic clay/HDPE by melting them in different conditions. The affections of process conditions and quantity of pelagic clay to the properties of composites were analyzed by testing their mechanical properties, thermo stability and barrier properties. According to test the structure of composites, it is indicated that pelagic clay has good compatibility with HDPE. The result shows that the pelagic clay can improve mechanical properties, thermo stability and barrier properties of HDPE properties effectively.