五水硫代硫酸钠连续结晶工艺中试研究

以金属铬生产过程中产生的废碱液为原料,采用Oslo结晶器,实现五水硫代硫酸钠结晶工艺的连续化。     

湖南省资兴市城市湿地资源网络连通性的生态水文水质效应研究

目前,城市湿地水文连通性的科学性问题研究仍然不够充分。为了进一步探讨城市湿地水文连通性的生态水文水质效应,根据湖南资兴城市总体规划的土地利用、湿地的位置与面积、形态设置了4组实验,运用SWMM模型进行水文和水质的模拟研究。结果表明,增加城市湿地间的连通性对于固体悬浮物(SS)、COD、氮磷污染物的减少有积极作用,并且建立植被缓冲带、增设人工湿地等低影响措施可以有效降低城市的地表径流,对于污染物的消减作用较为显著。其中在增加湿地连通性的基础上加入低影响设计方案的生态水文水质效应最优,能够较好地解决城市湿地中的湿地水质问题。     

高密度电法在岩溶地区工程勘察中的应用

分析岩溶地区的电性特征,总结不同岩溶形态的电阻率异常特征,并通过工程实例,说明高密度电法在岩溶区勘察中的应用效果。     

半周期中天法在初寻北中的应用研究

目前陀螺初寻北大多还是采用逆转点法,影响寻北速度且难以实现仪器自动化.由陀螺仪寻北中天法的基本原理出发,提出了一种固定照准部的初寻北半周期中天法.设计了如下初寻北方案:利用粗寻北传感器进入相对真北±1°的范围,再用半周期中天法进行初寻北测量.实验表明,半周期中天法应用于JT-15陀螺仪的初寻北精度可以达到±8′,而且初寻北效率提高了一倍.     

酱香型白酒酿造过程主要影响因素的分析

对酱香型白酒生产过程中的各影响因素进行分析。结果表明,优质、高产酱香型白酒酿造过程的影响因素概括起来主要为三大类:定向因素、营养因素和管理因素。只有对这些影响因素进行全面了解与掌握,才能生产出优质的酱香型白酒。     

基于热效应的涉水混凝土工程裂缝监测方法

相比于常规混凝土结构,水下混凝土结构开裂对结构安全具有更加恶劣的影响,准确、及时地监测裂缝的发生发展过程,对保障涉水工程安全、防止事故具有重要意义。本文基于流体-热源-裂缝的热效应耦合作用,提出水下混凝土结构裂缝监测的温度示踪法,并设计3种裂缝监测方案,分别采用监测管-多孔套管组件、监测管-空心套管组件和监测管-灌水管组件实现开裂信息与开裂部位热力学信息的转换。其中：前两种监测方案主要利用热传导原理,使开裂后裂缝周围介质的热力学参数发生改变,从而改变热量传递规律;第3种方案主要利用对流传热原理,通过灌水使裂缝截面产生对流传热效应,从而提高传热速度。针对上述3种监测方案,分别制作了混凝土梁试件,采用光纤光栅温度传感器和陶瓷加热管组成的传感加热单元开展了瞬态传热模型试验,根据热源降温曲线的分段特征,定义了反映热源降温速度的判别指标,利用该指标进行裂缝的识别,并对3种方案的裂缝识别效果进行分析和对比。结果表明：3种监测方案均能很好地判断是否有裂缝产生;在裂缝定位方面,方案3效果更好;在裂缝宽度定量识别方面,方案1无法识别裂缝宽度,方案2仅可在流动水环境中识别裂缝宽度,方案3可根据渗漏流量识别裂缝宽度。     

DMF萃取精馏精制高纯度甲缩醛的模拟研究

甲缩醛是一种重要的化工原料,是由甲醇和甲醛反应生成,由于甲缩醛和甲醇存在共沸,普通精馏难以提纯至99%以上,需采用特殊精馏加以分离。N,N-二甲基甲酰胺(DMF)是一种高沸点的含氮类有机溶剂,通过氢键与甲醇形成络合物降低甲醇的挥发度,提高甲缩醛对甲醇的相对挥发度,从而使甲缩醛和甲醇较易分离。本文利用化工流程模拟软件Aspen Plus采用萃取精馏,以DMF为萃取剂,对甲缩醛生产中的产品精制进行了模拟计算,详细分析了萃取精馏塔理论板数、进料位置、溶剂比和回流比对产品浓度的影响,结果表明,最优工艺方案为:理论板数30,甲缩醛进料位置23,萃取剂进料位置4,溶剂比1.0,回流比1.8,塔顶产品甲缩醛含量达到99.9%,为分离过程的优化操作和设计提供依据。     

玉米皮纤维发酵培养裂褶菌的转录组分析和重组α-L-阿拉伯呋喃糖苷酶的异源表达

本文优化了玉米麸皮固体发酵制备阿魏酰低聚糖（Feruloylated oligosaccharides,FOs）的工艺条件。利用“一般认为安全”（Generally recognized as safe,GRAS）真菌好食脉孢霉（Neurospora sitophila）为发酵菌种,以FOs含量为指标,通过单因素实验和响应面试验优化了培养基和培养条件,包括接种量、发酵时间、发酵温度、加水量。结果表明：250 mL锥形瓶装玉米麸皮5 g、玉米麸皮质量2%（w/w）的豆粕,接种量1.17×10⁵个孢子/瓶、发酵时间75 h、发酵温度28 ℃、加水量15.2 mL,在此条件下FOs产量为（1.52±0.02） μmol/g,与模型预测的理论值（1.56 μmol/g）接近,较优化前提高了60.83%。综上,经过发酵工艺的优化显著提高了产物中FOs的含量,这为提高玉米麸皮的附加值、拓宽玉米麸皮FOs制备路径提供了新思路。     

Effects of the spaces available for cations in strongly acidic cation-exchange resins on the exchange equilibria by quaternary ammonium ions and on the hydration states of metal ions

The spaces (voids) available for cations in the five exchange resins with varying exchange capacities and cross-linking degrees were estimated, on the basis of the additivity of molar volumes of the constituents. Tetraalkylammonium ions (NR(4)(+); R: Me, Et, Pr) may completely exchange potassium ion on the resin having a larger void radius. In contrast, the ratio of saturated adsorption capacity to exchange capacity of the resin having a smaller void radius decreased with an increase in size of NR(4)(+) ions, due to the interionic contacts. Alkali metal ions could be exchanged quantitatively. While the hydration numbers of K(+), Rb(+), and Cs(+) were independent of the void radius, those of Li(+) and Na(+), especially Na(+), decreased with a decrease in void radius. Interionic contacts between the hydrated ions enhance the dehydration. Multivalent metal ions have the hydration numbers, comparable to or rather greater than those in water. A greater void volume available due to exchange stoichiometry released the interionic contacts and occasionally promoted the involvement of water molecules other than directly bound molecules. The close proximity between ions in the conventional ion-exchange resins having higher exchange capacities may induce varying interactions.     

Highly Conductive Few‐Layer Graphene/Al2O3 Nanocomposites with Tunable Charge Carrier Type

An ex situ strategy for fabrication of graphene oxide (GO)/metal oxide hybrids without assistance of surfactant is introduced. Guided by this strategy, GO/Al₂O₃ hybrids are fabricated by two kinds of titration methods in which GO and Al₂O₃ colloids are utilized as titrant for hybrids of low and high GO content respectively. After sintered by spark plasma sintering, few‐layer graphene (FG)/Al₂O₃ nanocomposites are obtained and GO is well reduced to FG simultaneously. A percolation threshold as low as 0.38 vol.% is achieved and the electrical conductivity surpasses 10³ Sm^?1 when FG content is only 2.35 vol.% in FG/Al₂O₃ composite, revealing the homogeneous dispersion and high quality of as‐prepared FG. Furthermore, it is found that the charge carrier type changes from p‐ to n‐type as graphene content becomes higher. It is deduced that this conversion is related to the doping effect induced by Al₂O₃ matrix and is thickness‐dependent with respect to FG.