酸-酶联用液化法制备小麦淀粉麦芽糖浆的工艺研究

摘要：以小麦淀粉为原料,利用盐酸、中温α【一淀粉酶共同液化进行麦芽糖的制备。采用单因素实验结合正交实验法优化工艺参数。结果表明：酸一酶联用液化法的最佳工艺条件为：淀粉浆料液比（3：10）,5％盐酸添加量12mL,酸化时间12min,温度100℃,浓度为0．0143g／100mL的中温仅一淀粉酶加酶量8ml,酶液化时间30min,pH值5．4,温度64℃,所得液化液DE值为8．12％。通过无机酸与酶法共同液化小麦淀粉得到的液化液DE值控制在具体数值范围内,为以小麦淀粉为原料制备麦芽糖浆的工业生产提供了理论依据,也为下一步对小麦淀粉在板框过滤时出现的困难分析奠定基础。     

基于微观力学分析的散粒体静力液化本构模型

针对散粒体的静力液化特性,在散粒体颗粒运动微观力学分析的基础上,在临界状态土力学框架内建立了一个简单的静力液化弹塑性本构模型.模型屈服函数和和硬化规律根据Chang提出的砂土微观力学模型,通过积分粒间接触力为宏观的应力不变量而建立,考虑了与材料状态相关的剪胀性和初始密度对散粒体应力-应变关系的影响,并采用非相关联的流动法则.模型参数简单且有较明确物理意义,可以通过室内三轴试验确定.模型的数值结果与Toyoura砂以及砂-粉混合土的三轴不排水剪切试验的应力-应变曲线和应力路径吻合较好.     

挤密碎石桩抗液化性能分析

给出了碎石桩处理可液化地基土孔隙水压力比计算公式,并结合工程实际,考虑径向排水及垂向排水条件下,对孔隙水压力比进行计算,结果表明,经碎石桩处理后可液化地基土完全消除液化.     

水库大坝地基地震液化特性及动力有限元分析

为了考虑尔王庄水库大坝地基地碰液化及动力特性，首先通过室内动三轴试验研究粉土、粉砂在动荷载作用下的孔压累积特性。提出了选择双幅应变达到5％作为土样液化的标准；然后采用现场标贯试验和室内动三轴试验对水库坝基中的粉土、粉砂层进行了液化判别，并对判别结果进行了对比分析；同时在液化判别的基础上利用有效应力动力分析方法对坝基土体进行了考虑渗流和不考虑渗流的地震液化的非线性动力有限元分析，并将液化的判别结果与现场标贯试验、室内动三轴试验的判别结果进行对比，从中得出一些有益的结论可供类似工程参考。     

地震砂土液化可能性的非确定性灰色预测方法

地震作用下的饱水砂土体系是一内部信息部分已知、部分未知的灰色系统，反映其液化可能性的指标值实际上是一些灰数。取平均粒径、相对密度、标准贯人击数和上覆有效压力作为评价砂土液化可能性的指标，以它们在各级烈度下液化现场资料的统计均值作为参考数列，将已知烈度区内待预测砂土的指标实测值作为被比较数列，计算它们之间的关联度。若最大关联度值所对应的参考数列烈度大于待预测区，则判为液化；反之，则判为不液化；若相等     

深厚覆盖层岩组划分及主要工程地质问题

深厚覆盖具有结构松散、岩性不连续，在水平和垂直方向有较大变化、成因类型复杂、物理力学性质呈较大不均匀性的特点。深厚覆盖层可按其成因、物质组成、结构特征及厚度变化等作为岩组划分的依据。宝兴水电站坝址覆盖层按此依据可划分为６大岩组。     

低压氧液化流程与中压氧液化流程的比较

简单介绍了现有钢厂用液化设备流程的分类 ,主要从液化流程本身的特点和降低液化装置能耗两方面来探讨低压氧液化流程和中压氧液化流程。     

Real-time monitoring of hemicellulose liquefaction in ethylene glycol

Xylan was used as a model material to study the liquefaction of hemicellulose in the presence of ethylene glycol. The ReactIR^TM reaction analysis system was used to monitor the entire liquefaction process online. The results showed that xylan was decomposed and transferred to liquid phase. The gel permeation chromatography results of the liquid products showed that the weight average molecular of xylan decreased signi?cantly to around 1728 g/mol after liquefaction. Gas chromatography-mass spectrometry revealed that the ethylene glycol liquefaction products from xylan include ethylene glycol and its derivatives, alcohols, aldehydes, ketones, some acids and their esters.     

Laboratory-scale liquefiers for natural gas: A design and assessment study

Exact knowledge of natural gas composition is essential in custody transfer to determine the energy content of the delivery. However, for liquefied natural gas (LNG), a reliable composition determination is difficult. Here, we describe the design of a laboratory-scale reference liquefier that enables the validation and calibration of optical spectroscopy sensors by providing them with a sample of metrologically traceable composition. Hence, it is crucial to avoid fractionation of the sample during liquefaction. This is realized by supercritical liquefaction of a reference gas mixture in conjunction with a special vapor–liquid-equilibrium (VLE) cell. As this is a demanding high-pressure application, low-pressure condensation as liquefaction method was also assessed. Through experimental investigations and VLE calculations, preservation of the composition of the produced liquid sample during condensation was studied. We conclude that under optimized conditions, validation, and calibration measurements of optical sensors can be performed on condensed liquids, which, however, needs further confirmation.     

低变质煤热解技术分析

概述低变质煤外热式与内热式热解工艺．对比分析了各自的工艺特点及生产成本。