Presence of indigestible peptide aggregates of soybean meal in pig ileal digesta residue

With the purpose of analysing the molecular size and composition, proteinaceous material was extracted from the insoluble components of a digesta sample obtained from pigs fed a feed consisting of only soybean meal. Gel permeation chromatography indicated that the alkali‐extractable fraction of the proteinaceous material from the residue was of relatively high apparent molecular weight. However, the combined results from gel electrophoresis, RPLC‐MS, and MALDI‐ToF MS showed that the extracted protein material was in fact, to a high extent, composed of aggregated peptides. To our knowledge this has not previously been described. Aggregates extracted by dilute alkali were fully degraded upon subsequent proteolytic treatment. N‐terminal sequencing of selected protein bands from SDS‐PAGE gels indicated the presence of partly degraded β‐conglycinin alpha subunits in the residue. Copyright © 2007 Society of Chemical Industry     

我国混凝土骨料的现状与问题

针对目前我国天然矿石资源短缺、乱采滥挖砂石的现象屡禁不止、砂石质量严重失控的现状,应提高对砂石重要性的认识,引导砂石行业成为保护环境、开发建设用地、充分利用废弃资源的主力军。发展以工业废渣及淤泥、岩石为原料的人造轻骨料,积极开展再生骨料的应用研究工作。     

水淬铜渣作为混凝土组分的研究

本文从理论和应用两方面就水淬铜渣作为混凝土组分的问题进行了系统的研究。试验发现:水淬铜渣具有微火山灰效应;铜渣混凝土的工作性较差,但掺加适量微集料后会显著改善其工作性;铜渣混凝土在物理力学性能和耐久性能方面与普通混凝土差别不大;铜渣颗粒与水泥石之间粘结良好,铜渣的微火山灰效应能改善界面过渡层。研究表明:水淬铜渣作为混土的组分,不仅具有与普通混凝土相同的物理力学性能和耐久性能,还能取得可观的经济和环境效益。     

沥青质分子聚集体中π-π相互作用的研究

采用量子力学与分子动力学相结合的方法对形成沥青质分子聚集体的分子间π-π相互作用进行了研究。结果表明：沥青质分子间的π-π相互作用能随着分子芳香环数的增加而增大;分子中含有的杂原子显著增加了沥青质分子间的π-π相互作用能;沥青质分子的支链长度及类型能够影响π-π相互作用能的大小;当沥青质分子聚集体中含有多个π-π相互作用时,其分子间的聚集作用力会大大增加;沥青质分子间形成π-π相互作用的过程中,分子间有少量的电子转移;色散作用是π-π相互作用中的主要作用。     

基于骨架密实理论的矿料级配设计方法研究

现行的《沥青路面施工技术规范（JTGF40-2004）》中给出的矿料级配范围过宽,给实际工程的配合比设计带来较大困难。以杭州湾大桥南接线路面工程为背景,通过对国内设计方法的研究和室内的对比试验,提出了简便易行的矿料级配设计方法。     

基于几何形态学影响的集料建模及评价方法

集料几何学特性是影响颗粒复合材料力学性能的重要因素,也是实现复合材料性能精确设计的理论基础。以颗粒增强树脂基复合材料(particle-reinforced resin matrix composite, PRMC)为研究对象,采用PFC和3D MAX联合创建了精细的数字集料,分析集料综合几何学特性对PRMC动态损伤特性的影响,进一步细化并分离出集料单一几何学特征,通过分级替换不同粒径的圆形集料研究集料单一几何学特性对PRMC力学特性的影响。研究结果表明：集料几何学特性影响原始微损伤的分布,引导裂纹的扩展并最终决定PRMC的压缩破坏模式,并且压缩破坏过程存在典型的随机损伤特性;集料的形状、棱角和纹理通过降低集料间的流动性提高PRMC的抗压强度,而集料骨架系统需要在分形维数、级配级数、最大粒径和最大最小粒径比之间寻求最佳参数组合来提高PRMC的抗压强度。

     

青海省东部山区旱作农田土壤团聚体特征研究

比较了青海省东部山区垂直梯度分布的三种旱作农田土壤(黑钙土、栗钙土、灰钙土),在0~60 cm土层的不同粒级土壤风干团聚体和水稳性团聚体含量间的差异,并结合其它土壤质量指标(有机质、粘粒)对不同土壤结构和抗侵蚀能力进行了综合评价。结果表明,>0.25mm风干团聚体、>0.25mm水稳性团聚体含量和土壤有机质含量与土壤类型间有密切关系。均表现为黑钙土>栗钙土>灰钙土。黑钙土和栗钙土的土壤有机质含量与>0.25mm水稳性团聚体间存在显著正相关关系(P<0.05),灰钙土则无明显相关性;三种土壤粘粒含量与>0.25mm风干团聚体和0.25mm水稳性团聚体含量间无明显相关性。各项指标综合比较,三种土壤抗侵蚀能力大小为:黑钙土>栗钙土>灰钙土。     

Influence of moisture states of natural and recycled aggregates on the slump and compressive strength of concrete

The influence of moisture states of natural and recycled aggregates on the properties of fresh and hardened concretes was investigated. Concrete mixes were prepared with natural and recycled aggregates at different proportions. The moisture states of the aggregates were controlled at air-dried (AD), oven-dried (OD) and saturated surface-dried (SSD) states prior to use. The ratio of cement to free water was kept constant for all of the mixes. At the fresh state, the slump loss for various concrete mixtures was determined, while the compressive strength was determined after curing for 3, 7 and 28 days. The test results showed that the initial slump values of the concrete mixtures were dependent on the initial free water contents, and the slump loss values of the mixtures were related to the moisture states of the aggregates. Slump loss was significant when 100% AD or OD recycled aggregate was used. The effect of the moisture states of the aggregates on the strength of the concretes prepared with OD and SSD state aggregates at early age (i.e., 3 and 7 days) was noticeable. The concrete prepared with the AD aggregates achieved the highest average strength values at 3, 7 and 28 days. However, at 28 days, the concrete strengths prepared with different types of aggregates were similar. The results suggested that an AD aggregate that contains not more than 50% recycled aggregate is optimum for producing normal strength recycled aggregate concrete.     

Java application for the superposition T-matrix code to study the optical properties of cosmic dust aggregates

In this paper, we report the development of a java application for the Superposition T-matrix code, JaSTA (Java Superposition T-matrix App), to study the light scattering properties of aggregate structures. It has been developed using Netbeans 7.1.2, which is a java integrated development environment (IDE). The JaSTA uses double precession superposition codes for multi-sphere clusters in random orientation developed by Mackowski and Mischenko (1996). It consists of a graphical user interface (GUI) in the front hand and a database of related data in the back hand. Both the interactive GUI and database package directly enable a user to model by self-monitoring respective input parameters (namely, wavelength, complex refractive indices, grain size, etc.) to study the related optical properties of cosmic dust (namely, extinction, polarization, etc.) instantly, i.e., with zero computational time. This increases the efficiency of the user. The database of JaSTA is now created for a few sets of input parameters with a plan to create a large database in future. This application also has an option where users can compile and run the scattering code directly for aggregates in GUI environment. The JaSTA aims to provide convenient and quicker data analysis of the optical properties which can be used in different fields like planetary science, atmospheric science, nano science, etc. The current version of this software is developed for the Linux and Windows platform to study the light scattering properties of small aggregates which will be extended for larger aggregates using parallel codes in future.     

基于废弃混凝土再生二灰碎石的应用研究

回弹法检测废弃混凝土构件并快速分级生产不同质量等级再生骨料及再生粉状颗粒,添加石灰及粉煤灰配制二灰碎石。设计正交实验,通过重型击实、无侧限抗压强度等试验分析再生骨料质量、二灰掺量、再生粉状颗粒等因素对其性能影响规律并得出最佳配比范围。试验表明,再生骨料及再生粉状颗粒可以不同程度替代天然骨料及粉煤灰,配置力学性能满足承载基层要求的半刚性基层材料。