Investigation on the application of steel slag-fly ash-phosphogypsum solidified material as road base material

The aim of the present work is to prepare a new type of steel slag-fly ash-phosphogypsum solidified material totally composed with solid wastes to be utilized as road base material. The mix formula of this material was optimized, the solidified material with optimal mix formula (fly ash/steel slag=1:1, phosphogypsum dosage=2.5%) results in highest strength. The strength development, resilience modulus and splitting strength of this material were studied comparing with some typical road base materials, the 28- and 360-day strength of this material can reach 8MPa and 12MPa, respectively, its resilience modulus reaches 1987MPa and splitting strength reaches 0.82MPa, it has higher early strength than lime-fly ash and lime-soil road base material, its long-term strength is much higher than cement stabilized granular materials, the solidified material has best water stability among those road base materials, it can be engineered as road base material with competitive properties. The strength formation mechanism of this solidified material is discussed also.     

The microscopic network structure of mussel (Mytilus) adhesive plaques

Marine mussels of the genus Mytilus live in the hostile intertidal zone, attached to rocks, bio-fouled surfaces and each other via collagen-rich threads ending in adhesive pads, the plaques. Plaques adhere in salty, alkaline seawater, withstanding waves and tidal currents. Each plaque requires a force of several newtons to detach. Although the molecular composition of the plaques has been well studied, a complete understanding of supra-molecular plaque architecture and its role in maintaining adhesive strength remains elusive. Here, electron microscopy and neutron scattering studies of plaques harvested from Mytilus californianus and Mytilus galloprovincialis reveal a complex network structure reminiscent of structural foams. Two characteristic length scales are observed characterizing a dense meshwork (approx. 100 nm) with large interpenetrating pores (approx. 1 µm). The network withstands chemical denaturation, indicating significant cross-linking. Plaques formed at lower temperatures have finer network struts, from which we hypothesize a kinetically controlled formation mechanism. When mussels are induced to create plaques, the resulting structure lacks a well-defined network architecture, showcasing the importance of processing over self-assembly. Together, these new data provide essential insight into plaque structure and formation and set the foundation to understand the role of plaque structure in stress distribution and toughening in natural and biomimetic materials.     

三维蠕虫状介孔二氧化硅对CO2吸附性能的研究

研究了有机胺固载3D蠕虫状介孔二氧化硅MSU-J的表面结构、介孔类型、氮含量以及吸附温度对CO_2吸附性能的影响,并采用傅里叶红外光谱、透射电镜、N_2吸附/脱附、热重分析和元素分析等方法研究了介孔结构和CO_2吸附性能。结果表明,采用浸渍法对MSU-J进行氨基改性的效率明显高于接枝法,产物具有较高的CO_2吸附量,且水化处理后介孔MSU-J表面的Si-OH得以再生使氨基的负载量增加,CO_2吸附量从43.2mg/g增加到52.6mg/g。与SBA-15相比,氨基改性后MSU-J的CO_2吸附量从28.4 mg/g增加到154.5 mg/g,远大于前者的23.4~65.4mg/g。吸附温度对MSU-J吸附CO_2的影响很大,且随吸附温度降低,吸附量升高,在室温时达最大值125mg/g,故MSU-J的低温吸附性能优异。     

Tensile and dynamic mechanical analysis of the distal portion of mussel (Mytilus edulis) byssal threads.

Dynamic mechanical analysis was used to record the behaviour of hydrated and dehydrated byssal threads under tensile stress and during dynamic thermal cycling. Fresh byssi, and byssi aged two weeks prior to testing, were used to further study the effects of age on the mechanical properties of this material. It was found that while older threads demonstrated increased stiffness, age did not necessarily affect their ultimate tensile strength. Dehydration had a more pronounced effect on thread stiffness and also increased the ultimate strength of the material. In their dry state, byssal threads displayed multiple yield points under tension and these, it is suggested, could equate to different phases within the bulk of the material. Dynamic analysis revealed glass transition (Tg) and ecologically relevant operational temperatures for byssi, where their modulus (E') remained constant. These discoveries are related to the ecological function of byssal threads and to the emerging field of biomimetics.     

硅胶负载离子液体的CO2吸附性能影响因素研究

采用浸渍法将两种离子液体负载在A型和B型硅胶上,研究了硅胶种类和活化温度、离子液体种类和负载量、吸附剂孔径分布(PSD)等对CO2吸附效率的影响。结果表明,制得的吸附剂均具有发达的微孔结构,在0.4~0.8nm连续分布;A型硅胶经500℃活化,且[bmim]PF6用量为20%(质量分数)时,负载样品具有较好的CO2吸附性能,273K和0.1 MPa时为3.68%(质量分数);载体中引入[bmim]PF6,可以协同提高负载样品的CO2吸附量和CO2/N2选择性,且吸附速率高于纯[bmim]PF6。     

The low magnetic field properties of superconducting bulk yttrium barium copper oxide-sintered versus partially melted material

A comparison of the low magnetic field properties of sintered (990°C) and partially melted samples (1050°C) has been performed. Changes in the microstructure produced by recrystallization from the melt result in a significant increase in flux pinning at 77 K. Low-frequency (10–100 Hz), low-a.c. magnetic field (0.01–9.0 Oe) a.c. susceptibility data show that gross changes in the a.c. loss component accompanies the observed changes in microstructure. The effects of applied d.c. magnetic fields (10–220 Oe) on the a.c. responses of these microstructures have also been probed. Data are analyzed and critically discussed in terms of current models appropriate for granular superconductors and in terms of older models appropriate for metallic alloys and compounds. Particular attention is given to published interpretations of the in-phase or loss component of the a.c. magnetic susceptibility and to the possible roles which minority phases and sample inhomogeneities may play in determining the detailed a.c. responses of these high-T _coxides.     

A study of parameters affecting the continuous CO2 laser cuts

Abstract

This work attempts to discover, by experimentation, some of the parameters governing cutting efficiency in perspex of a continuous CO₂ laser. The experimentation took the form of taking cuts in specimen pieces with the laser. While varying the parameters of speed of cut and position of the focal plane of the laser beam relative to the surface of the perspex, all other parameters were kept constant. These experiments produced conclusive ideas of the optimum position of the focal plane and the best speeds for cutting perspex at the same time producing the best cut quality obtainable. When the theoretically predicted minimum cut width is compared with the experimentally obtained results, the agreement is found to be almost exact.     

温度和CO2对热解成型生物质炭孔隙结构和表面分形维数的影响

通过SEM分析和氮气等温吸附实验,对不同热解温度和CO_2浓度下热解成型炭样进行孔隙结构特性分析,同时根据FHH方程计算了炭样的孔隙表面分形维数D_S,研究了孔隙结构与表面分形维数的关系以及温度和CO_2浓度对两者关系的影响。结果表明:表面分形维数可以较好地表征孔隙结构的复杂性和炭样表面不规则性,但是与BET比表面积(S_(BET))、总孔积和平均孔径没有直接联系,而是与微孔面积和微孔容积含量占比较为一致。在氮气热解情况下,600℃时炭样孔隙结构最为发达,S_(BET)和D_S都达到最大值。在CO_2和N_2混合气氛下,S_(BET)随着CO_2浓度的增加而变大,而D_S则是先减小后变大,当CO_2浓度大于10%后才会随着CO_2浓度的增加而变大。     

Growth and properties of CuInS2 thin films

Single phase copper indium disulphide (CuInS₂) thin films of thickness between 60 nm and 650 nm with the chalcopyrite structure are obtained on NaCl and glass substrates by flash evaporation. The films were found to ben-type semiconducting. The influence of the substrate temperature on the crystallinity, conductivity, activation energy and optical band gap was studied. An improvement in the film properties could be achieved up to a substrate temperature of 523 K at a molybdenum source temperature of 1873 K.     

Microwave properties of vanadium borate glasses

A.c. conductivity, dielectric constant and loss, and variation with temperature (302–373 K) for four different compositions of V₂O₅-B₂O₃ glasses were reported at 9.586 GHz microwave frequency. The quality factor (Q) and attenuation factor (α being the important parameters in the microwave range of applications were also studied. The change in the dielectric constant and loss was observed with composition of V₂O₅. The maximum loss was found to be at 15V₂O₅ mol‰ The peak was observed in loss with temperature.     

Effect of oxide additives on the properties of high temperature superconductor,YBa2Cu3O7

The effect of oxide additives-CuO, SiO₂, Y₂O₃, Bi₂O₃ and ZnO in 1–10 mol% on the sintering and superconducting properties of YBa₂Cu₃O₇ was studied. SEM studies indicated improvement of grain size and interconnectivity due to the additives, the best results being obtained with Bi₂O₃, SiO₂ and Y₂O₃. The superconducting transition temperature is unaffected (92±2 K) even with 10 mol % of the additives. ZnO, however, decreases theT _c as expected.     

CO2养护混凝土技术研究进展

CO_2养护混凝土技术是将CO_2与新拌混凝土在成型后接触,使CO_2与水泥熟料矿物间发生化学反应,进而使得新拌水泥混凝土在很短的时间内凝结硬化的养护技术。它不仅可以获得性能更好的混凝土,还可以合理利用CO_2并且节能减排,是一项有前景的可持续发展技术。综述了CO_2养护混凝土的反应机理、影响养护过程的关键因素、CO_2养护混凝土对微观结构以及耐久性的影响、后续水养护等方面的研究进展,并对CO_2养护混凝土技术的未来发展进行了展望。     

富锂锰表面超临界CO2辅助包覆磷酸锰锂及其电化学性能

富锂锰Li[Li0.2Mn0.54Co0.13Ni0.13]O₂(LMCN)是新一代高能量密度锂电池的理想正极材料,但存在首次不可逆容量高、循环寿命短以及电压衰减严重等问题。为此,本研究提出了一种可有效改善富锂锰性能的超临界表面包覆磷酸锰锂(LMP)工艺,探讨了不同包覆量对富锂锰材料结构和电化学储锂性能的影响。结果表明,LMP包覆量为3%(质量分数)的LMP3-LMCN样品,在30 mA·g-1电流密度下,首次库伦效率高达81.1%,经过100次充放电后循环容量保持率为79.2%,并且电压衰减仅为0.47 V,在1 500 mA·g-1电流密度下容量为88.76 mAh·g-1,明显优于纯相富锂锰。     

Photoelectrochemical properties of TiO2 nanotube arrays: effect of electrolyte pH and annealing temperature

The effect of electrolyte pH and annealing temperature on the formation of TiO₂ nanotube arrays in connection with the photoelectrochemical response was investigated in this article. Well-aligned TiO₂ nanotube arrays were fabricated by anodisation of Ti foil in an electrolyte consisting of 1?M of glycerol (85?wt% of glycerol and 15?wt% of water) with 0.5?wt% of NH₄F at 30?V for 30?min. The pH of the electrolyte was varied from pH 1 to 7. With the increase of electrolyte pH to neutral condition, the length of the nanotube arrays was increased from ～320 to 1100?nm. As-anodised TiO₂ nanotube arrays were amorphous in nature. However, anatase phase was observed after annealing at 400°C and polycrystalline anatase and rutile phase could be observed by heating up to 500°C in air atmosphere. Based on the results obtained, the length and crystalline phases of TiO₂ nanotube arrays affect the performance of photoelectrochemical response and photoconversion efficiency significantly.     

A study of uv preionization pulsed tea CO2 laser

Abstract

A uniform volumetric discharge was obtained by means of an auxiliary UV preionization in a home‐made TEA CO₂ laser. The maximum output pulse energy of this laser system was about 12J per pulse with a pulse duration of 80 ns. The ratio of electric field to neutral particle density (E/N) in this laser was 7.6×10^‐16 V cm². The peak power and pulse shape of the laser were studied. The time delay between the predischarge and the maindischarge during the stable operation of this laser system has also been studied. It was observed that the laser was operating with uniform glow discharges when the time delayed between the predischarge and the maindischarge was in the range of 1.0 μs to 6.0 μs. The spark array used as a preionizer for producing the UV radiation in this system is new, simple, durable, and can be easily fabricated.     

纳米Al2O3改性玻璃纤维增强复合材料低温力学性能研究

简述了纳米Al2O3改性玻璃纤维增强环氧树脂基复合材料的制备,并对其常温、低温力学性能进行实验。结果表明,常温、低温下,复合材料的力学性能随着纳米Al2O3含量的增加都呈现先增强后减弱的趋势。低温处理使复合材料的力学性能得到提升,并且低温下Al2O3的引入对复合材料强度的改善效果比常温下明显,Al2O3含量为1%(质量分数)时,拉伸强度提高比例高达16.61%。其原因是低温下基体强度增大,另外基体热膨胀系数大,收缩明显,界面粘接强度增大,纳米Al2O3颗粒在界面处与树脂基体结合更深入,从而使纳米粒子阻碍微裂纹扩展的能力更强。     

Modulating calcium phosphate formation using CO2 laser engineering of a polymeric material

The use of simulated body fluid (SBF) is widely used as a screening technique to assess the ability of materials to promote calcium phosphate formation. This paper details the use of CO₂ laser surface treatment of nylon® 6,6 to modulate calcium phosphate formation following immersion in SBF for 14 days. Through white light interferometry (WLI) it was determined that the laser surface processing gave rise to maximum Ra and Sa parameters of 1.3 and 4.4 μm, respectively. The use of X-ray photoelectron spectroscopy (XPS) enabled a maximum increase in surface oxygen content of 5.6%at. to be identified. The laser-induced surface modifications gave rise to a modulation in the wettability characteristics such that the contact angle, θ, decreased for the whole area processed samples, as expected, and increased for the patterned samples. The increase in θ can be attributed to a transition in wetting nature to a mixed-state wetting regime. It was seen for all samples that calcium phosphate formed on each surface following 14 days. The largest increase in mass, Δg, owed to calcium phosphate formation, was brought about by the whole area processed sample irradiated with a fluence of 51 J cm^− 2. No correlation between the calcium phosphate formation and the laser patterned surface properties was determined due to the likely affect of the mixed-state wetting regime. Strong correlations between θ, the surface energy parameters and the calcium phosphate formation for the whole area processed samples allow one to realize the potential for this surface treatment technique in predicting the bone forming ability of laser processed materials.     

LLDPE/EPDM共混物的超临界CO2微孔发泡研究

研究了线性低密度聚乙烯(LLDPE)/三元乙丙橡胶(EPDM)橡塑共混物在超临界CO_2中的微孔发泡行为。利用扫描电子显微镜对发泡样品的泡孔形貌进行了分析和表征;采用差示扫描量热仪分析了共混物的热性质;分别利用旋转流变仪和万能试验机分析得到样品的流变性能和力学性能。采用一定量的LLDPE与EPDM共混,压制标准试样,然后在高压反应釜中进行发泡,讨论了LLDPE/EPDM共混物中橡塑的质量比、饱和温度、饱和压力对材料泡孔结构和泡孔均匀性的影响。利用超临界CO_2作物理发泡剂,对发泡条件进行优化,可得到泡孔尺寸规整、泡孔密度高且回弹性和韧性较好的发泡闭孔材料。     

固相法合成氮掺杂碳纳米管及其二氧化碳吸附性能研究

以二乙烯苯(DVB)和1-乙烯基-3-丁基咪唑溴盐([VBIm]Br)共聚物为原料,铁氰化钾为催化剂前驱体,在600~1000℃下固相碳化制备了掺氮纳米碳管(NCNT)块体。利用SEM、TEM、Raman、XPS、物理吸附等对样品进行了表征。采用KOH在600~800℃下对NCNT进行活化,发现处理温度和时间是影响其孔结构的关键因素。CO_2吸附实验表明,单位孔容的微孔吸附量与碳材料表面氮含量之间存在明显的线性关系。