Li2O和B2O3对含稀土氧化物结晶器保护渣结晶相的影响

通过在结晶器保护渣中添加Li2O和B2O3作助熔剂,在实验室内模拟渣膜的形成条件,结合岩相和扫描电镜能谱分析,研究了Li2O3和B2O3对含稀土氧化物保护渣结晶矿物组成的影响.结果表明:稀土氧化物可以促进保护渣中枪晶石析出,抑制玻璃相形成,提高保护渣结晶率;当稀土氧化物含量达到一定数值,保护渣结晶矿物中可以形成稀土硅酸钙相,稀土氧化物继续增加,会有未溶稀土氧化物固态质点出现;保护渣中加入少量B2O3和Li2O作助熔剂,不仅可以促进硅灰石生成,而且能够有效抑制高熔点的枪晶石和稀土硅酸钙形成,防止渣膜形成过程中过早析出高熔点相.     

高速连铸结晶器保护渣

概述了高速连铸的技术特点及其对结晶器保护渣的要求,论述了高速连铸结晶器用保护渣必须保证的理化性能,总结了高速结晶器保护渣的研究现状,并提出了今后对高速连铸保护渣研制工作的建议。     

放热型颗粒状结晶器保护渣

为了提高钢质量,必须要改善结晶器保护渣性能,颗粒状结晶器保护渣可以保持良好的工作环境.然而,颗粒状结晶器保护渣保温性能不如粉末状保护渣.为了开发添加金属的放热型颗粒状结晶器保护渣,改善作业环境,开发了添加金属材料的结晶器保护渣新技术,使保护渣有足够热量,并能够改善钢质量.     

结晶器保护渣熔化速度测定方法的研究

通过分析结晶器保护渣熔化速度测定方法的国内外现状 ,提出用坩埚法测定的方法。与灰熔点仪法和GX -高温物性测试仪法进行对比研究 ,表明在测定结果的稳定性和代表性方面 ,坩埚法是目前结晶器保护渣熔化速度测定的合适方法。     

低碳和超低碳钢用结晶器保护渣的开发

结晶器保护渣对稳定连铸和改善铸坯质量都非常重要。通过应用新开发的高粘度结晶器保护渣,大幅度减少了汽车钢板用低碳和超低碳钢薄卷板的夹杂物性缺陷和气泡性缺陷,提高了卷板质量。     

高铝电工钢用"SIPS系列"结晶器保护渣的开发

高铝电工钢不同于普通钢,在连铸过程中,钢液中的铝和保护渣中的SiO2发生反应,致使结晶器保护渣的特性发生很大变化,并导致漏钢等连铸事故,造成产量下降。日本品川耐火材料公司开发出高铝电工钢用新型结晶器保护渣。该保护渣可保持稳定的熔渣层厚度,消除了漏钢事故。此外,连铸浇次由1个浇次增加到多个浇次,促进了连铸产量的提高。     

高速连铸用保护渣性能研究及建议

概述了高速连铸的特点及对结晶器保护渣的要求，论述了高速连铸保护渣必须保证的理化性能，总结了高拉速结晶器用保护渣的研究现状，提出了今后对高速连铸保护渣研制的工怍建议。     

结晶器保护渣渣膜结构的模拟研究

通过获得现场不同位置及由结晶器渣膜热流模拟仪获得不同时刻的渣膜,对比分析了渣膜的厚度、结晶率、晶体的分布、大小、类型. 结果表明,结晶器渣膜热流模拟仪铜探头浸入45 s时获得的实验室渣膜与现场弯月面附近45 s的现场渣膜厚度和结晶率相当;现场渣膜随位置在晶体分布上演变规律与实验室渣膜随时间的演变类似;现场渣膜与实验室渣膜的晶体的类型相同,但是晶体大小还存在差异. 因此,可以通过结晶器渣膜热流模拟仪方便、有效的模拟实际结晶器内保护渣渣膜的结晶行为.     

MSMPR结晶器中二水硫酸钙的结晶动力学研究

应用粒数平衡技术,在MSMPR结晶器中,对二水硫酸钙结晶过程的动力学进行了研究,获得了二水硫酸钙在60℃情况下成核速率B0与晶体生长速率G之间的动力学表达式:B0=k2Gi=1.142×103G0.54,对实际工业生产具有一定的指导意义。     

FTIR spectra of pure helical crystalline phases of syndiotactic polystyrene

By quantitative evaluation of the spectral changes associated with guest removal from clathrate films as well as by infrared dichroism measurements on uniaxially oriented films, three infrared absorbance peaks (at 1379, 1154 and 841 cm⁻¹) prevailingly associated with the amorphous phase have been located for syndiotactic polystyrene (s-PS) samples with helical crystalline phases. A detailed study relative to the infrared peaks in the wavenumber range 870-820 cm⁻¹, corresponding to phenyl C-H out-of-plane bending, has shown that the 841 cm⁻¹ peak is fully associated with conformationally disordered sequences only for samples including trans-planar crystalline phases (α and β) but not for samples including helical crystalline phases (γ, δ and clathrates). This result has been rationalized on the basis of different intermolecular interactions between phenyl rings, occurring for trans-planar and helical s-PS crystalline phases. Moreover, a preparation procedure leading to fully unoriented films has been described for helical semicrystalline films, which generally present different kinds of uniplanar orientation. FTIR spectra of these fully unoriented semicrystalline films, by subtracting out the amorphous phase contribution with a procedure based on the 1379 cm⁻¹ peak, have allowed a straightforward isolation of the spectra of the helical s-PS crystalline phases and the quantitative determination of the amorphous content.     

丁烯氧化脱氢钼铋系催化剂:晶相之间的协同效应

钼铋系催化剂以其优良的性能一直以来都是丁烯氧化脱氢研究和应用的热点。本文简述了已有研究中对钼铋系催化剂及改性后的多组分催化剂的晶相结构及其与反应性能间关系的研究进展。指出在钼铋催化剂中,有较多晶格缺陷的α-Bi₂(MoO₄)₃提供吸附位,氧流动性较强的γ-Bi₂MoO₆提供晶格氧,二者的协同作用提高了催化剂的活性。而在改性后的多组分钼铋系催化剂中,添加的组分与钼铋元素结合生成新的晶相,产生了更多的晶格缺陷及氧供体,从而提升了催化性能。对于钼铋系催化剂进一步改进的方向,本文认为在添加组分的方法基础上,还可以从催化剂表面结构方面入手,进行进一步的深入探究。     

两段式煤气化技术在氟化氢反应转炉和烘粉炉上的应用

以发生炉煤气取代燃料油应用在氟化氢反应转炉及烘粉炉上 ,通过两段式煤气化技术可以降低氟化氢产品的生产成本 ,改善工作环境。介绍了煤气取代燃料油的可行性以及发生炉煤气站工艺方案的选择情况 ,建议在工业窖炉上大力推广 ,可以改变当前工业窖炉燃油成本高和燃煤对环境污染的状况。     

Preparing polymer brushes on poly(vinylidene fluoride) films by free radical polymerization

Grafting of polymer brushes on the poly(vinylidene fluoride) (PVDF) films was carried out by the surface‐initiated free radical polymerization. Surface‐initiators were immobilized on the PVDF films by surface hydroxylation and esterification of the surface‐tethered hydroxyl groups with 4,4′‐azobis(4‐cyanopentanoic acid) (ACP). Homopolymer brushes of methyl methacrylate (MMA) were prepared by free radical polymerization from the azofunctionalized PVDF surface. The chemical composition and topography of the graft‐functionalized PVDF surfaces were characterized by X‐ray photoelectron spectroscopy (XPS), attenuated total reflectance (ATR) FTIR spectroscopy, and atomic force microscopy (AFM). Kinetics study revealed an exponential increase in the graft concentration of polymer brushes with the reaction time, indicating that the chain growth from the surface was consistence with a chain polymerization. Water contact angles on PVDF films were reduced by surface grafting of MMA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 857–862, 2006     

亚微米SiO2粉体对无水泥铁沟浇注料性能的影响

以致密刚玉、碳化硅等为主要原料,以w（SiO₂）=99.9%的亚微米SiO₂粉体(d₅₀=0.242μm)为结合剂,制备了一种新型无水泥铁沟浇注料。研究了亚微米SiO₂粉体加入量（质量分数分别为3%、4%、5%、6%、7%、8%、9%）对其性能的影响,并从亚微米SiO₂粉体的粒度分布、红外光谱等角度,分析探讨了亚微米SiO₂粉体的作用机制。结果表明：1)亚微米SiO₂粉体可以单独作为铁沟浇注料的结合剂制备出无水泥铁沟浇注料;2)相比传统铁沟浇注料,无水泥铁沟浇注料在加水量、高温抗折强度等方面取得突破性进展,亚微米SiO₂粉体的最佳加入量为4%～6%（w）。     

Calcium-activated geopolymer ceramics: Study of powder calcination and amorphous gel phases

Burnt coal cinder (BCC), the main solid waste in coal and electric power industries was used to prepare the geopolymer ceramics (GC) in this study. The optimum preparation technology of BCC-based GC and the effects of calcination and calcification on the compressive strength of BCC-based GC were studied. Through the calcification of BCC with CaO, NaAlO₂ and sodium silicate solution (SS) were separately used as the co-activator and silica additive to prepare BCC-based GC. The optimal single-factor conditions determined by the experiment were BCC:CaO:NaAlO₂:SS = 18:3:2:4 (g:g:g:mL) and the liquid–solid ratio was 0.46. The compressive strength of BCC-based GC was 32.78 MPa (28 days). It was obtained that the calcination of calcified BCC below the temperature of 1000°C can effectively remove the fixed carbon in BCC but will destroy amorphous active aluminosilicate. The microstructure study showed that BCC reacted in the ternary system of Ca–Al–Si to form a variety of amorphous products (C–(A)–S–H and (N, C) –A–S–H). Along with the three-dimensional amorphous gel structure as the dominant phase, the coexistence and interlacing of various amorphous gels made the microstructure more compact and increased the compressive strength of the BCC-based GC. GCs with various amorphous phases have been successfully prepared at low temperature, and it also provided a new idea for the utilization of low-activity silicate solid wastes.     

粉末状高纯氟化镁的研制

氟化镁广泛用于热压晶体、真空镀膜和光学玻璃的制备。目前国产氟化美多为硬块状固体,不仅难以直接使用,而且在粉碎加工过程中还易受到污染,最终影响产品的性能。粉末状高纯氟化镁的研制成功,很好的解决了上述难题。     

Characterization of thermotropic liquid crystalline polyester/polycarbonate blends: Miscibility,rheology, and free volume behavior

Miscibility, rheology, and free volume properties of blends of thermotropic liquid crystalline polymers (TLCPs) (Vectra A950) and polycarbonate (PC) are studied in this work. Despite the unusual increase in T_g of the PC phase, the blends are found to be generally immiscible. Transesterification may occur during blending and be the cause of the increase of T_g of the PC phase and the partial miscibility of the blends at high TLCP concentrations. With regard to the melt rheology of these materials, according to a three‐zone model, dynamic moduli of Vectra A950 show plateau‐ and transition‐zone behavior, while PC exhibits terminal‐zone behavior. The blends show only terminal‐zone behavior at low Vectra A950 contents (≤50%) and terminal‐ and plateau‐zone behavior at higher Vectra A950 contents. The relaxation time of Vectra A950 is much longer than PC and the blends have relaxation times greater than additivity. Both the complex and steady shear viscosities of the blends increase with the addition of Vectra A950. This is attributed to interfacial association, which retards the reorientation and alignment of the Vectra A950 phase in the molten state. The Cox–Merz rule holds true for PC but not for Vectra A950 and the blends. Free volume properties on an angstrom scale evaluated by positron annihilation lifetime spectroscopy (PALS) indicate that Vectra A950 has smaller, fewer free volume cavities than PC and the variation of free volume behavior in the blends can be explained in terms of blend miscibility. The measured densities of the blends agree well with the free volume fractions of the blends determined from PALS. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2319–2330, 2000     

纳米TiO2粉体晶相组成定量分析计算方法

通过理论计算,给出了纳米TiO2混晶中金红石相和锐钛矿相相对含量的计算公式,与文献中实验方法得出的计算公式吻合,理论计算和实验结果得以很好的相互验证。     

化妆品用超细结晶蚕丝粉末的制备及表征

用质量分数为85%的磷酸催化水解桑蚕茧,茧与磷酸的质量体积比为1∶4时,在100℃条件下反应,可制得平均粒径为250 nm的结晶性丝粉,收率达70%以上.并对样品进行了扫描电镜、示差热分析、X-射线粉末衍射等表征分析.