模拟高钠高放废物铁硼磷酸盐玻璃固化体的结构和性能

以36Fe2O3--10B2O3--54P2O5为基础玻璃,制备了不同模拟高钠高放废物包容量的铁硼磷酸盐玻璃固化体,用Fourier变换红外光谱测试方法系统研究了由废物包容量引起的玻璃固化体结构变化,并用溶解速率法初步测试了固化体的化学性能。结果表明:随着废物包容量的增加,固化体试样结构中(PO4)3-四面体基团增加,[BO3]基团向[BO4]基团转变,磷酸盐基团彼此间的连接程度减小,Fe—O—P键在包容量为25%(质量分数)到30%时存在量较大。玻璃固化体网络结构以(PO4)3-四面体基团为主,易水化的(PO3)-磷酸盐基团的含量很小。但固化体结构中[BO3]基团的存在量还较大,该组分的基础玻璃网络形成体氧化物配比还可进一步优化。当废物包容量小于40%时,固化体不同浸泡周期的质量损失速率均在10--8 g/(cm2·min)数量级。     

Kiyoteru Tokuyasu: a pioneer of cryo‐ultramicrotomy

In July 2015 Professor K.T. Tokuyasu passed away in San Diego giving us the opportunity to reflect on the contribution this electron microscopist made to the field of immunocytochemistry. His work provided a sensitive, minimally invasive approach to producing thin sections of biological material for labeling with antibodies. His approach has been applied to a wide range of biological applications and provided important information on cellular processes.     

Inertization of Coal Ashes by the Vitrification Technique: A Mixture Design Approach

This article deals with the study of the vitrification mechanism as an inertization method for coal ashes contaminated with heavy metals. Ashes from coal (thermoelectric) and wastes from mining of fluorite and feldspar and from plating were used to compose vitreous systems using a mixture design. The chemical composition of the wastes was determined by XRF and the formulations were melted at 1450°C for 2 h using 10% (mass) of Na₂CO₃ (as a fluxing agent). The glasses were poured into a mold and annealed (600°C). The characteristic temperatures were determined by thermal analysis (DTA, air, 20°C/min) and the mechanical behavior by HV. As a result, the softening temperature is strongly dependent on silica content of each glass, and the fluorite residue, being composed mainly by silica, strongly affects on the glass transition (T_g) and softening (T_s) temperatures. The hardness by micro-indentation of all glasses is mainly affected by the plating (galvanic) residue due to the high iron and zinc content of this waste.     

Thermodynamic modelling of the spontaneous vitrification process using transformation diagrams

Spontaneous vitrification is a phenomenon where a crystalline phase transforms to the amorphous phase on annealing at low temperatures. It has been reported to occur in several binary alloy systems. This phenomenon has been widely investigated in the Ti–Cr system through experiments as well as thermodynamic modeling. The models reported in literature suffer from several drawbacks. They are not consistent with experimental observations. These models treat this non-equilibrium process as an essentially equilibrium process albeit involving two meta-stable phases. The thermodynamics of the “spontaneous vitrification” process has been modeled using the concept of Transformation Diagrams. This method considers the thermodynamics of non-equilibrium phase transformation and does not involve assumptions of equilibrium at any stage. A significant conclusion derived from the present model is that it is the close-packed hcp structure that transforms to the amorphous phase whereas the transformation of the relatively open bcc structure to the amorphous phase is forbidden thermodynamically. These conclusions are in contrast with the predictions of the earlier models.     

Photorheology of Fast UV‐Curing Multifunctional Acrylates

Summary: The fast photopolymerization of different multifunctional acrylates was analyzed by means of photorheology. The materials studied included a penta/hexaacrylate monomer and two different acrylated hyperbranched polymers. The sensitivity of the commercial rheometer was improved several‐fold, by a combination of an adaptive filter algorithm and improved data treatment, using powerful oversampling acquisition hardware. The novel set‐up was capable of monitoring up to a five orders of magnitude increase in shear modulus within short experiment timescales (about 10 s). The improvement in sensitivity and acquisition rate enabled the induction time, gelation, and vitrification of the multifunctional acrylates to be determined. In addition, the influence of UV intensity on stiffness build‐up within these materials was studied. In the case of the penta/hexaacrylate system, gelation and vitrification were detected as distinct events, in contrast to the second‐generation hyperbranched polyester, for which vitrification could not be identified. These findings are related to the difference in the glass transition temperature of the cured networks.

Absolute value of the complex shear modulus as a function of time for different acrylate monomers during UV curing.     

淀粉玻璃化转变及其对食品品质影响

淀粉是以谷物为原料的食品主要成分,而淀粉玻璃化转变对食品品质,特别对质构具有显著影响。该文在有关玻璃态和玻璃化转变理论基础上,综述淀粉玻璃化转变分析方法、影响因素及其对食品品质影响,并对今后研究方向进行展望。     

垃圾焚烧飞灰柴油炉熔融固化过程的特性分析

采用柴油炉,对杭州某生活垃圾焚烧厂的焚烧飞灰连续进行了6个多月、日处理规模为500 kg的熔融固化中试实验,探讨了在1 260~1 350℃熔融过程中,原灰(未经处理的飞灰)、水洗灰的减容减重、成分变化、物相组成以及熔渣浸出毒性的变化规律,同时对烟气中的二恶英和常规污染物进行了测试.结果表明,原灰和水洗灰的减容减重率均随着温度的升高而增大,在1 350℃时,减容率分别为83.7%和81.5%,减重率分别为28.6%和21.9%.由于水洗灰中以氯化物形式挥发的成分减少,使之在相同温度下的减容减重率均小于原灰.随着温度的升高,原灰和水洗灰中CaO、A12O3和SiO2的相对百分含量均增大,其中以SiO2最为显著.根据相关浸出毒性鉴别标准测得溶渣中的重金属浸出浓度低于该标准限值,可作为一般废物填埋.烟气中二恶英总毒性当量浓度远低于标准限值,常规污染物也均符合我国2001年颁布的《危险废物焚烧污染控制标准》(GB18484—2001).     

Preservation of biological materials under desiccation

A number of life forms, including seeds, certain nematodes, bacterial and fungal spores, and cysts of certain crustaceans, show an ability to survive desiccation. The present article reviews the literature available on this subject and critically evaluates the evidence for various mechanisms that may be responsible for these phenomena. Specific mechanisms considered include vitrification (glass formation) by sugars and other polyhydroxy compounds that are accumulated by the desiccated structures, specific effects of polyhydroxy compounds on membranes, effect of “compatible solutes” on conformation of key proteins, as well as other biochemical mechanisms.

The article presents potential applications relevant to food technology and to biotechnology and reviews the research required to materialize more effective use of desiccation in food and biopreservation.     

模拟高放废液玻璃固化体溶解液的ICP／AES分析法

利用我院制造的高浓盐雾化器解决了送样过程中同心雾化器堵塞的问题,并且详细观察了存在于溶解液中诸元素,尤其是具有复杂光谱结构的元素之间的谱线干扰现象。我们注意到硫的最灵敏的主共振线S 180.73nm为Ca线所干扰,为此,采用次灵敏的S 1820.4nm谱线;还观察到铀和钛对Li323.26nm和Na330.24nm的谱线干扰。改变等离子体的工作参数,即增加载气流,减小高频功率,可提高被测元素Li,Na的谱线强度,同时降低干扰元素的谱线强度,从而可以在U,Ti共存的溶液中测定Li和Na。本法可测定玻璃模拟体中主次成分,共十九个元素:B,Si,Na,Li,Al,Ca,Mg,Sr,Zr,Ti,Ce,La,Nd,Fe,Cr,Mn,Ni,S,U。方法的相对标准偏差随元素不同约为1%～5%。