天然纳米结构材料——江苏盱眙凹凸棒土的特性及开发应用前景

本文对江苏盱眙凹凸棒土的样品进行比表面积测量,比表面积230m2／g。用X光衍射和X光荧光分析表明,此样品主相为坡缕石(Palygoskite),其分子式:(Mg,Al)5(Si,Al)8O20(OH)2?8H2O,这种颗粒的集合体具有特有的毡状结构,旧名山软木。显微结构棒晶长约1μm,直径约20nm,是天然纳米结构材料。本文指出,利用凹凸棒土比表面积大有很强的吸附性,开发出无毒粮食保鲜剂和无抗菌素的胃肠药;利用凹凸棒土一维针状纳米结构,对其表面进行改性,减弱凹凸棒土晶束之间的作用力,以利于在聚合物中分散,提高聚合物物理性能,开发凹凸棒土在聚合物材料上的应用。

超声场对热浸土铝镀层组织特性的影响

稀土铝镀层具有较好的耐腐蚀、抗高温氧化特性，超声外场的施加可使其性能得到进一步增强。本文通过改变超声施振参数制备了稀土铝镀层，并采用扫描电镜、电子探针、X-射线衍射等测试分析方法，分析了超声（功率、频率、施振时间）对稀土铝镀层成分、组织结构及镀层厚度的影响规律。采用热循环氧化及全浸试验研究了稀土铝镀层耐腐蚀性和抗氧化性的变化规律，并侧重分析了超声场对表面层及过渡层界面的作用行为。针对稀土铝表面层中组织不均匀的问题，通过在热镀过程中施加超声场，细化了表面层组织，改善了镀层的均匀性，超声处理可使稀土铝镀层的抗氧化性提高3倍，镀层耐腐蚀性也增强。研究表明，超声功率对表面层厚度影响存在一定闲值，超声外场作用使稀土铝镀层总厚度减薄，减薄程度达30％左右，但减薄的趋势随着超声功率的增大而变缓。研究揭示出超声作用下稀土铝镀层厚度减薄的根本原因是表面层厚度的减小，而超声对过渡层厚度的影响较小。分析发现，超声场对表面层和过渡层的界面处结合形态影响较为显著，当超声场较强时，界面结合由微齿状变为平滑形态。超声外场作用使得热浸稀土铝过渡层中的原子比例受到影响，在一定程度上影响了过渡层中Al、Fe原子比和Si元素的分布。通过实验得出了常规稀土铝镀层在循环高温氧化环境中破坏行为模式：裂纹在表面萌生一裂纹向内扩展至基体一裂纹沿界面扩展并导致镀层剥落，超声作用使其抗热循环氧化能力增强。

The mechanism of PEO process on Al–Si alloys with the bulk primary silicon

This study focuses on mechanism of ceramic coating on Al-Si alloys with bulk primary Si using plasma electrolytic oxidation (PEO) technology. Al-Si alloys with 27-32% Si in weight were used as substrates. The morphologies, composition and microstructure of PEO coatings were investigated by scanning electron microscopy (SEM) with energy dispersive X-ray system (EDX). Results showed that the PEO process had four different stages. The effect of bulk Si is greatly on the morphology and composition of coatings at first three stages. Anodic oxide films formed on Al and Si phases, respectively. When the voltage exceeded 40 V, glow appeared and concentrated on the localized zone of interface of Al and Si phase. Al-Si-O compounds formed and covered on the dendrite Si phase surface, and the coating on bulk Si, which was silicon oxide, was rougher than that on other phase. If the treatment time was long enough, the coatings with uniform surface morphologies and elements distribution will be obtained but the microstructure of inner layer is looser due to the bulk Si.

非晶硅薄膜制备及其晶化特性研究

用磁控溅射法在K9玻璃上沉积了非晶硅（a—Si）膜和a—Si／Al膜，并将其在流动的N2气氛下进行退火。对退火前后的样品进行Raman光谱、XRD和SEM表征和分析。Raman光谱表明随着退火温度的升高，a-Si膜的散射峰出现了明显的蓝移，但XRD结果表明薄膜仍为非晶态；而a—Si／Al膜在温度很低时就已经开始晶化。

稀土对铝及变形铝合金性能影响和作用机理研究

稀土对铝及铝合金具有很多良好作用。根据国内外有关铝合金发展趋势的报道，铝合金向中强高工艺高强耐热、超塑、微量元素改善合金性能等方向发展稀土在这些方面对铝合金有着很好的作用效果。因此研制新型铝合金，研究稀土对铝合金组织和性能的影响及稀土作用机现，有着重要的意义。稀土在铝合金中的应用已经引起了国内外研究工作者的关注。近几年此方面研究尤为活跃。我国是一个稀土蕴藏量较大的国家，研究稀土在铝合金中的作用，可以更好地发挥我国的资源优势，对国民经济的发展将起着重要的作用。有关稀土在铝合金中的应用研究，国外开展的较早。我国始于七十年代。合金工作者对稀土在铝合金中的作用进行了大量的研究，确认了稀土可以改善铝合金的组织和性能，改善工艺性能，表面光泽性和耐腐蚀性但是，目前的研究还没有形成系统和全面的理论，由于研究条件和目的不同，很多的研究还处于实验室阶段，对某些问题还研究得不够深入，不够全面。如：1. 稀土对金属铝组织和性能影响；2. 稀土对铝合金枝晶组织细化作用和晶体结构影响；3. 稀土如何改善铝合金的加工工艺性能，提高铝合金的成品率；4. 稀土对提高合金沉淀硬化速度，使GD区快速析出，时效峰提前；5. 铝热还原法，较低温度下制取铝稀土合金，特别是重稀土合金；6. 稀土铝合金的加工硬化过程研究；7. 稀土在变形铝合金中的存在状态和分布规律；基于上述问题和国内对铝合金的需求，本文主要做了如下几个方面的工作：1. 研制了RE-Al-Mg-Si挤压型材合金，稀土是采用向工业电解槽中加入混合稀土化合物同铝一起共电沉积，制取稀土铝合金，然后配制成RE-Al-Mg-Si合金。对其组织，晶体结构，性能，沉淀硬化过程等进行了研究得出如下结论：①. 稀土可使Al-Mg-Si合金强度提高10-20%，硬度提高10%左右；②. 稀土可以改善Al-Mg-Si合金的加工性能，在挤压温度下具有较大的高温塑性。稀土可使铝镁硅合金晶粒细化，再结晶温度和过烧温度提高，允许在较宽温度范围内进行热处理；③. 稀土可使Al-Mg-Si合金表面致密，光亮，改善耐腐蚀性和光学特性；④. 稀土可使铝基体晶胞体积减小，晶胞体积的减小值和强度、硬度提高成很好的直线关系。首次提出稀土对铝合金的“晶胞收缩效应”；⑤. 稀土在铝镁硅合金中分布规律是晶内晶界都有稀土存在，晶界多于晶内。稀土和Si，Fe等共存于晶界。⑥. 稀土可促使GP区快速析出，弥散的第二相质点在位错线上析出，起着钉扎位错，增大位错密度的作用，因而时效硬度提高，时效峰提前；为短时高温时效提供了实验依据；2.研制了RE-Al-Zn-Mg中强合金。稀土的加入是采用对掺法，对合金的组织、性能，加式硬化过程，时效工艺及稀土分布规律进行了研究，得出如下结论：①. 稀土可改善合金加工性能，尤其是高温延伸率，当稀土为0.489%时达到750%，是未加稀土的合金两倍多。该合金具有超塑性。②. 铸态或变形后，稀土对组织都有细化作用；③. 该合金加工硬化过程具有三个阶段，经过线性回归处理成很好的直线关系。④. 稀土可使Al-Zn-Mg合金的时效峰提前约4小时；⑤. 稀土合金的新相在位错密度线上析出，阻碍位错移动，使严结构组织保持较大的位错密度，从而改善合金性能；⑥. 该合金具有满意的强度，可适合挤压，轧制等变形加工。3. 研究了稀土对金属铝组织和性能的影响。用铝热还原法制得Al-RE合金。实现了较低温度下重稀土化合物的铝热还原。采用电解复膜工艺，制得金相样品；使合金的细节组织清晰可见。研究了组织和性能，得出如下结论：①. 稀土对铝的细化作用，枝晶细化更明显，这主要是稀土在铝中的溶质再分配，造成了结晶前沿的过冷区，使铝晶粒以树枝状晶长大，由于稀土元素在铝中的溶质分配系数不同而表现在细化晶粒方面有一定的差异；②. 稀土在铝中主要分布在晶界和枝晶界，晶内也有稀土存在；③. 稀土可以提高纯铝的机械性能和高温塑性；④. 通过铝热还原，可在较低温度不制得Dy、Eu、Gd、Y等重稀土铝合金。

Ti/莫来石陶瓷界面反应的俄歇电子能谱研究

结果表明，在淀积过程中，最初淀积的Ti与衬底表面的氧形成Ti-O键，界面区很窄；450℃退火1h后，有少量元素态Al、Si原子析出，界面区有所展宽，但变化不大；650℃退火1h后，界面发生强烈反应，有TiO和Ti-Al、Ti-Si化合物生成。850℃退火1h后，除上述反应产物外又生成了Ti_2O。

20Na、23Al、24Si的b＋缓发粒子发射及相关的天体反应率的实验研究

以兰州放射性束流线装置(RIBLL)为依托,利用弹核碎裂机制产生了远离稳定线的核素,通过研究一些放射性核素<'20>Na、<'23>Al、<'24>Si的β<'+>缓发粒子特性,并结合核结构的测量,初步研究了<'16>O(α,γ)<'20>Ne、<'22>Na(p,γ)<'23>Mg以及<'23>Mg(p,γ)<'24>Al反应.实验测量到了β<'+>缓发母核(先驱核)的半衰期,缓发粒子的能谱和相对强度,并根据壳模型计算指定了部分激发能级的自旋,进而得到了它们的相对共振强度以及热核反应率等.通过实验,我们测量了5.627,5.788,6.725MeV等几个<'20>Ne<'*>的低能缓发α粒子能级,得到<'20>Na的其半衰期T<,1/2>=459±7ms,给出了10.584MeV和10.843MeV的两个能级的相对共振强度分别为0.59eV、1.2eV,计算了其直接俘获的贡献和低能共振态对反应率的贡献;对于<'22>Na(p,γ)<'23>Mg反应,我们重点测量了<'23>Mg的靠近<'22>Na+p俘获阈附近的能级,将探测器的探测阈降低到了200KeV左右,并新发现了一条激发能级具有缓发质子的特性,其能量为8.916MeV(衰变质子能量为1.337MeV),为了验证测量结果的准确性,我们进行了第二次测量,结果证实了8.916MeV及9.598MeV能级具有缓发质子特性,其中9.598MeV能级的缓发质子在2000年被K.Perajarvi等发现,并又新测量到了能量为8.990,9.060,9.138,9.374MeV的四个能级也存在缓发质子特性.实验得到<'24>Si的衰变半衰期为104±10ms,第一次测量到<'24>Mg低能的几个衰变质子谱线,它们在天体物理中具有重要的作用.

Post-steam-treatment of Mo/HZSM-5 catalysts: An alternative and effective approach for enhancing their catalytic performances of methane dehydroaromatization

Post-steam-treatment is a facile and effective method for improving the catalytic performances of Mo/HZSM-5 catalysts in methane dehydroaromatization under nonoxidative conditions. The treatment can enhance the stability of the catalyst and also give a higher methane conversion and a higher yield of light aromatics, as well as a decrease in the formation rate of carbonaceous deposits. (27)Al, (29)Si, and (1)H multinuclear magic angle spinning nuclear magnetic resonance, X-ray photoelectron spectroscopy, X-ray diffraction, X-ray fluorescence spectroscopy, and thermogravimetric analysis measurements as well as catalytic reaction evaluations were employed to conduct comparative studies on the properties of the catalysts before and after the post-steam-treatment. The results revealed that the number of free Bronsted acid sites per unit cell decreased, while more Mo species migrated into the HZSM-5 channels for the 6Mo/HZSM-5 catalysts after the post-steam-treatment. In addition, the average pore diameter was also larger for the post-steam-treated catalysts, and this was advantageous for mass transport of the reaction products. However, a severe post-steam-treatment, i.e., with longer treating time, of the 6Mo/HZSM-5 catalyst will lead to the formation of the Al(2)(MoO(4))(3) phases, which is detrimental to the reaction.

High gain in hybrid transistors with BAlq(3)/Alq(3) isotype heterostructure emitter

We report the fabrication of permeable metal-base transistors based on bis(2-methyl-8-quinolinolato-N1,O8)-(1,1'-biphenyl-4-olato) aluminum (BAlq(3))/tri(8-hydroxyquinoline) aluminum (Alq(3)) isotype heterostructure as emitter layer. In this transistor, n-Si was used as the collector, LiF/Al as the emitter electrode, and Au/Al bilayer metal as the base. We show that the leakage current is greatly reduced in Al/n-Si/Au/Al/BAlq(3)/Alq(3)/LiF/Al devices with respect to Al/n-Si/Au/Al/Alq(3)/LiF/Al devices due to the utilization of BAlq(3)/Alq(3) isotype heterostructure emitter, leading to high common-base and common-emitter current gains at low driving voltages.

High gain in hybrid transistors with vanadium oxide/tris(8-hydroxyquinoline) aluminum emitter

We report the electrical characterization of hybrid permeable-base transistors with tris(8-hydroxyquinoline) aluminum as emitter layer. These transistors were constructed presenting an Al/n-Si/Au/Alq(3)/V2O5/Al structure. We investigate the influence of the V2O5 layer thickness and demonstrate that these devices present high common-base and common-emitter current gain, and can be operated at very low driving voltages, lower than 1 V, in both, common-base and common-emitter modes.

添加元素对AB_2型Laves相合金电化学性能的影响

比较系统地研究了 AB2 型 Laves相合金 Zr0 .9Ti0 .1Ni0 .1Mn0 .7V0 .3 M0 .1( M=None,Ni,Mn,V,Co,Cr,Al,Fe,Mo,Si,C,Zn,Cu和 B)的相结构和电化学性能以及高温和低温放电性能等 .结果表明 ,1 4种合金均具有六方 C1 4型 Laves相的主相晶体结构 ,同时 ,含有少量立方 C1 5型 Laves相和一些由 Zr.9Ni11及 Zr Ni组成的非 Laves相 ;添加 V和 Mn可提高 AB2 合金的放电容量 ;添加 B和 Mn则显著提高了 AB2 合金的高倍率放电性能和低温放电容量 ;添加 Al,C,Si和 Co对合金电极的循环稳定性改善明显 ;而 Mn,Ni,V,Fe,Cu,Mo和 B等却不同程度地降低了循环稳定性 ;添加 Si,Mo,V,Cr和 Al可明显改善合金电极的自放电性能 ;添加 Si,Cr,V可显著改善 AB2 合金电极的高温放电性能 .讨论了各种添加元素影响合金性能的可能原因.

稀土对Al—Mg—Si合金晶体结构参数的影响

在研究和探索稀土对铝合金作用机理的过程中,稀土的良好作用已为越来越多的研究所证实。目前,有关稀土对铝合金宏观组织和性能影响的研究报道较多,但有关稀土对铝合金晶体结构参数的影响报道很少。本文研究了稀土对Al-Mg-Si合金晶体结构参数的影响,可以说,稀土能够提高铝合金的机械性能,在宏观组织上表现为晶粒细化,在微观结构上表现为晶胞参数变小。

流体地球化学：成因、流动和流体-岩石相互作用及塔里木盆地实例研究

Geofluid in sedimentary basins is related to petroleum generation, migration, accumulation and preservation, and is a topic of geological frontier. By integrating the multi-discipline methods of petroleum geochemistry, sedimentology, hydrogeology, petroleum geology and experimental geochemistry, the thesis has carried out experiments of microcline dissolution in solutions with organic acids, crude oil, brines with high total dissolved solids (TDS), and has dealt with Al distribution between the crude oil and the brines after the experiments. Cases for study includes Central Tarim, Hetianhe Gas Field and Kucha forland basin with data containing fluid chemistry and isotopic compositions, thin sections of sandstones and carbonates, homogenization temperatures and salinities of fluid inclusions, isotopic compositions of bulk rock and autigenic minerals. The aims are to elucidate fluid origin and flow in the three areas, effect of hydrocarbon emplacement on diagenesis, and to show occurrence of microbe-mediated, and thermochemical sulfate reduction in the Tarim Basin. Microcline dissolution experiments show that after 100 hour, part of the dissolved Al distributes in the crude oil, and the Al concentrations in the crude oil rise when organic acids are added. The result can be used to explain that most oilfield waters in the Tarim Basin are characterized by less than 3mg/L Al. Crude oil added to the solutions can enhance microcline dissolution, which is also observed in the case - Silurian sandstones with early crude oil emplacement in the Central Tarim. Al and Si have higher concentrations in the experiments of oxalic acid than of acetic acid under the same pH conditions, suggesting that there exist Al-oxalate and Si-oxalate complexes. Presence of acetate can enhance the activity of Ca and Al, but Al concentrations have not been increased significantly due to formation of small Al-acetate complex during the experiments. Relationships between δD and δ~(18)O in conjunction with chemistry of oilfield waters show that the waters are evaporated connate waters, which subsequently mixed with meteoric water, and were influenced by water-rock interactions such as salt dissolution, dolomitization of calcite, albitization of feldspar. In the Hetianhe Gas Field where salt dissolution took place, δD and δ~(18)O values can be used to trace nicely meteoric water recharge area and flow direction, but TDS can not. Part of the waters have high TDS but very light δD and δ~(18)O. When combined with paleo-topography, or fluid potentials, meteoric water is suggested to flow eastward in the Hetianhe Gas Field, which is the same with the Central Tarim. Whist in the Kuche forland basin, meteoric water may have permeated Cambrian-Ordovician strata. Relationship between ~(87)Sr/~(86)Sr and 1/Sr can be used to indicate migration and mixing of brines from carbonate strata (low ~(87)Sr/~(86)Sr ratio but high Sr content), clastic strata (high ~(87)Sr/~(86)Sr ratio but low Sr content) and crystalline basement (high ~(87)Sr/~(86)Sr ratio and heavy δ~(18)O value). Using this approach, it can be found that ~(87)Sr-depleted brine from Ordovician carbonates have migrated up to and mixed with ~(87)Sr-enriched waters from Silurian and Carboniferous sandstones, and that Silurian brines have mixed with meteoric water. In the Kuche forland basin, brines from the Cambrian and Ordovician carbonates have higher ~(87)Sr/~(86)Sr ratios than those from the overlying sandstones, when combined with chemistry, δ~(15)N and ~3He/~4He ratios of the coexisting natural gases, suggesting that the brines were derived from the basement. There exists some debate on the effect of hydrocarbon emplacement on mineral diagenesis. Case-study from Silurian sandstones in the Central Tarim show that quartz has kept overgrowing secondarily when oil saturation was decreased by meteoric water flushing subsequently to hydrocarbon emplacement. Silicon precipitates on the water-wet quartz surface, leading to decreased Si concentration close to the surface. A Si grads can result in Si diffusion, which supplies Si for quartz overgrowth. Hydrocarbon oxidation-sulfate reduction is an important type of organic-inorganic interaction. Not only can it make secondary alteration of hydrocarbons, but generate H_2S and CO_2 gases which can improve reservoir property. Thermochemical sulfate reduction took place at the temperatures more than 125 ℃ to 140 ℃ in the Cambrian-Ordovician carbonates, the products - H_2S and CO_2 gases migrated up to the Silurian, and precipitated as pyrite and calcite, respectively. The pyrite has an average δ~(34)S value close to those of Ordovician seawater and anhydrite, and calcite has δ~(13)C value as low as -21.5‰. In the Hetianhe Gas Field, sulfate reduction bacteria carried by meteoric water flowing eastward may have preferentially depleted ~(12)C of light hydrocarbon gases, and results in heavier δ~(13)C values of the residual hydrocarbon gases and higher molar CO_2 in the natural gases in the west than in the east. Coexisting pyrite has δ~(34)S values as low as -24.9‰.

Methane dehydro-aromatization over a Mo/phosphoric rare earth-containing penta-sil type zeolite in the absence of oxygen

The dehydro-aromatization of methane over a Mo-modified penta-sil type high-silica zeolite containing phosphoric and rare earth oxide (abbreviated as Mo/HZRP-1) was investigated. As a modification of HZSM-5, HZRP-1 is also a good support for the preparation of Mo-based zeolite catalysts, and is active for methane dehydro-aromatization. Mo/HZRP-1 catalysts are more active at high Mo loadings compared with Mo/HZSM-5 catalysts. Al-27 MAS NMR spectra of Mo/HZRP-1 reveal that there are two kinds of framework Al in HZRP-1. It is suggested that only the tetrahedral coordinated Al atoms in the form of Al-O-Si species in the zeolite, in the proton forms, are responsible for the formation of aromatics.

A high-resolution solid-state NMR study on nano-structured HZSM-5 zeolite

Variations in the structure and acidity properties of HZSM-5 zeolites with reduction in crystal sizes down to nanoscale (less than 100 nm) have been investigated by XRD, TEM and solid-state NMR with a system capable of in situ sample pretreatment. As evidenced by a combination of Al-27 MAS NMR, Si-29 MAS, CP/MAS NMR and H-1 MAS NMR techniques, the downsize of the zeolite crystal leads to an obvious line broadening of the Al-27, Si-29 MAS NMR spectrum, an increasing of the silanol concentration on the external surface, and a pronounced alteration of the acidity distribution between the external and internal surfaces of the zeolite. In a HZSM-5 zeolite with an average size at about 70 nm, the nonacidic hydroxyl groups (silanols) are about 14% with respect to the total amount of Si, while only 4% of such hydroxyl groups exist in the same kind of zeolite at 1000 nm crystal size. The result of H-1 MAS NMR obtained using Fluorinert(R) FC-43 (perfluorotributyl amine) as a probe molecule demonstrates that most of the silanols are located on the external surface of the zeolite. Moreover, the concentration of Bronsted acid sites on the external surface of the nano-structured zeolite appears to be distinctly higher than that of the microsized zeolite.