羟乙基纤维素的乙酰乙酰化研究

乙酰乙酰基比羟基具有更高的反应活性 ,因此将乙酰乙酰基引入羟乙基纤维素可以提高其反应活性 ,为其后续接枝改性奠定基础。论文研究了将乙酰乙酰基团引入羟乙基纤维素的酯交换反应 ,着重探讨了反应温度、反应时间、反应物和催化剂用量等因素对该反应的影响 ,并用 IR、TG等分析手段对不同条件下的反应产物进行了表征。     

HEC固化改良土施工工艺研究

结合工程特点,采用高强耐水固化剂对路基填土进行了改良,探讨了固化土的施工工艺和质量保证技术措施.得出了工程各项指标均达到设计要求的结论,结论表明HEC固结改良土在同类工程中具有良好的适用性.     

高强耐水土壤固化剂工程应用研究

对HEC土壤固化剂固化沙质土和水泥固化沙质土的特点进行了比较研究。试验结果表明:HEC土壤固化剂的固土效果和经济性能均优于水泥固化土,是一种值得在工程中推广应用的土壤固化材料。     

西北内陆河流出山口以下水面曲线计算方法

为给堤防防洪工程设计计算水面曲线提供参考,以新疆喀什克孜河为例,研究了西北内陆河流的自然状况、洪水成因及类型特性,并探讨了克孜河流量沿程损失的处理方法,采用调查历史最大洪水沿河长变化的方法确定工程河段上、下游洪峰流量求得河道流量衰减率,应用HEC RAS和MIKE11方法计算水面曲线。结果表明,该方法行之有效、可靠,百年一遇水面线推求结果均低于堤防设计堤顶高程1.71~4.36 m。     

HEC子模型在降雨径流模拟中的应用研究

介绍了HEC（hydrology Engineering Center)模型包的组成和各子模块的功能。着重探讨了降雨径流子模型HEC—HMS模型的基本结构和松散耦合分布式运行控制方式,以及利用HEC—GEOHMS实现由DEM生成数字流域的运作过程。并以江西修水万家埠流域为例,结合运用2个子模型进行洪水过程模拟。初步模拟结果表明：HEC—HMS模型应用方便,具有较好的适用性。     

Modelling reach‐scale variability in sediment mobility: An approach for within‐reach prioritization of river rehabilitation works

Many Australian river ecosystems have been, and continue to be, adversely affected by increased channel dimensions and sediment supplies occurring in the period since European settlement. One of the key aims of river rehabilitation in these rivers is to help reduce sediment yield by preventing ongoing bank erosion and remobilization of instream bed material stores. While various tools have been developed to help identify sediment sources at the catchment scale, this is often at a resolution that is too coarse to be translated directly to on‐ground rehabilitation works, as most riverworks programs are designed and implemented at the reach or within‐reach scale. This paper provides a method of prioritizing rehabilitation at the within‐reach scale by using a high‐resolution reach‐scale modelling approach to examine the relative entrainment potential of sediment stores. The method has been developed for a 10 km reach of the upper Hunter River, NSW, Australia. Shear stress distribution is examined using the widely available model HEC‐RAS, and incorporating a detailed, LiDAR‐derived, representation of the in‐channel vegetation into a spatially distributed Manning's roughness layer. At the geomorphic unit scale, the results highlight that the elevated ‘bench’ units, which represent significant stores of sand and silt, are much more vulnerable to remobilization than the lower elevation gravel bar units. At the sub‐reach scale (500–2000 m) shear stresses are greatest in the most confined sections. While instream geomorphic heterogeneity has been significantly reduced in these locations, ongoing erosion is limited by bedrock and buried coarse gravel terrace material in the bed and banks. These results highlight the need for targeted rehabilitation strategies that account for within‐reach variability in entrainment potential as well as on‐the‐ground knowledge of sediment supply and geological controls. Copyright © 2010 John Wiley & Sons, Ltd.     

Sediment in Mosul Dam reservoir using the HEC‐RAS model

Mosul Dam, located on the Tigris River north of Iraq, is experiencing sedimentation problems, especially near the Al‐Jazeera pumping station that supplies the irrigation water for the Al‐Jazeera project. The sources of the sediment accumulated within the reservoir are from the Tigris River, as well as ten side valleys on both sides of the reservoir. The sediment inflow rate into the reservoir and the released values are considered on the basis of the operation schedule of the dam for the considered period from 1986 to 2011. The sediment loads were estimated on the basis of available measurements and estimated literature values. The HEC‐RAS 4.1 model was used for flows and sediments in the main river and reservoir. The model was calibrated for flow simulations (coefficient of determination r² = 0.87) and sediment routing based on bed level, (with resultant r² = 0.98 and Mean Absolute Deviation of 0.95). The Ackers–White equation was used in the HEC‐RAS model for sediment routing because of the wide range of sediment sizes in the study case. The resultant total accumulated sediment load volume was 1.13 km³, a value that is very close to the measured values (1.143 km³) obtained from a previous bathymetric survey. Furthermore, the model indicated most of the sediment (80.7%) was deposited during the first five of the dam operation.     

HEC水工泵送混凝土的基本性能试验研究

结合水电工程实际,对HEC水工泵送混凝土性能进行了试验研究.试验研究表明:HEC水工泵送混凝土具有混凝土用水量小、早期强度高和干缩变形小的优点,但也存在着泌水大且易板结的不足.     

Preparation and characterization of blend anion-exchange membrane from quarternized hydroxyethylcellulose/quaternized poly(vinyl alcohol)

阴离子交换膜是碱性直接甲醇燃料电池（ADMFC）的核心。本文将季铵化羟乙基纤维素（QHEC）和季铵化聚乙烯醇（QPVA）共混制备了一系列不同配比的QPVA/QHEC阴离子交换膜并对其进行热交联,对膜进行测试和分析,结果表明：膜表面均匀致密,低于300 ℃膜基本稳定;QPVA/QHEC共混膜的导电率随着QPVA量的增大而增大,在（2.0～7.8）×10－2 s/cm范围内,随着使用温度的升高逐渐升高;QHEC膜对甲醇有很好的阻隔效果,在20 ℃时,甲醇渗透率最低为2.49×10－6 cm2/s;随QPVA量的增加,共混膜的甲醇渗透率会略有增加。     

辛烯基琥珀酸羟乙基纤维素酯的性质及应用研究

以羟乙基纤维素(HEC)为原料,制备辛烯基琥珀酸羟乙基纤维素酯。通过傅里叶变换红外光谱紫外可见光谱、扫描电镜等分析表征了自制的辛烯基琥珀酸羟乙基纤维素酯的结构,粘度,透明度,乳化性及乳化稳定性以及冻融稳定性。酯化后的羟乙基纤维素酯表观粘度提高了60%,且不受pH的影响,乳化性能提高明显且乳化稳定性随着取代度的增加逐渐趋近于1。以辛烯基琥珀酸羟乙基纤维素酯替代常用的酪朊酸钠作为乳化剂,采用喷雾干燥法制得的油脂微胶囊颗粒包埋效果良好,表面油含量1.7%,包埋率达93.39%。