宽顶堰上平板闸门水力计算的探讨

根据平板闸门水流条件对流量系数的影响，对闸门的水流条件进行分类，通过试验研究，对平板闸门流量系数计算公式的适用条件进行了较为细致的讨论并加以分类，使闸门的水力计算更加清晰、准确，为工程计算提供了参考和依据。     

款冬叶片总黄酮提取工艺优化及抗氧化活性研究

以款冬叶片为试材,采用微波辅助法提取总黄酮,在单因素试验的基础上,采用正交实验法优化款冬叶片总黄酮提取工艺,同时以分光光度法测定提取物对1,1-二苯基-2-三硝基苯肼自由基(1,1-diphenyl-2-picrylhydrazyl,DPPH·)、羟基自由基(·OH)和超氧阴离子自由基(O-·2)的清除作用。结果表明:款冬叶片总黄酮最佳提取条件为乙醇体积分数70%,微波提取时间3 min,微波功率500 W,料液比1∶15 g·mL^-1,在该条件下,总黄酮的提取率为0.91%。款冬叶片总黄酮的质量浓度与抗氧化活性呈一定的线性关系,当总黄酮质量浓度为0.069 8 mg·mL^-1时,对DPPH·、·OH和O-·2的清除率分别达84.21%、84.10%和68.32%,表明款冬叶片具有良好的抗氧化能力,可作为天然的抗氧化剂进一步的开发和利用。     

超声波-微波协同法提取分蘖葱头有机硫化合物的工艺优化及其组分分析

以分蘖葱头为试材,采用超声波-微波协同法提取有机硫化合物,进行分蘖葱头有机硫化合物工艺优化试验,并利用气相色谱-质谱联用仪对提取物组分进行分离鉴定,以期为进一步研究和开发分蘖葱头功能组分提供参考依据。结果表明:最佳提取工艺为微波温度55℃、料液比1∶8 g·mL^-1、协同时间6 min、搅拌转速300 r·min^-1、超声波功率500 W,该条件下有机硫化合物得率为0.2771%±0.0023%。该条件得到15种有机硫化合物,含量较高的是噻吩类39.0678%±0.0043%,其次是三硫化合物14.1570%±0.0071%和硫醚类7.3872%±0.0052%,其中含量相对较高的有机硫化合物为2,4-二甲基噻吩、3,5-二乙基-1,2,4-三硫杂环戊烷、二烯丙基二硫醚。     

酸法提取柑桔皮果胶的条件研究

对采用酸法提取柑桔皮果胶的水料比、加热温度和时间进行了比较试验。结果表明,提取液的pH值为1.3～1.6,水料比为10:1,加热85℃、1～1.5小时,所得果胶溶液经浓缩、乙醇沉淀后,果胶的平均得率为9.9%～10.7%。     

枸杞中总黄酮的分析方法及提取工艺研究

以乙醇为溶剂,采用回流提取法提取宁夏枸杞中的总黄酮。通过正交试验,对影响提取效果的主要因素包括提取温度、提取时间、乙醇浓度和固液比进行优化。通过试验研究发现最优提取条件为:提取温度70℃,提取时间2.0h,乙醇浓度70%,固液比为1:20。此法为枸杞中黄酮类化合物的提取提供了参考。     

甘草渣中碱木质素的提取工艺研究

采用一般碱法从甘草渣中提取木质素,以水浴温度、恒温时间、碱液用量、碱液浓度为因素,进行正交试验,确定了其最佳提取工艺条件为:水浴温度40℃、恒温时间2.5h、碱液浓度0.8mol/L、碱液用量30 mL/g,木质素的提取率为4.88％.碱木质素的总羟基、酚羟基和醇羟基含量分别为5.43％、3.18％、2.43％.     

Improve Water and Nutrient Efficiency in Tomato Crop by a Dynamic Fertigation Management under Saline Conditions

The improvement of water and nutrient efficiency leads to a production model that is more sustainable with less water, fewer fertilizer inputs, and less environmental damages. High-technology fertigation equipment permits high precision in the nutrient solution application. Besides, the field measurement of soil water content by tensiometers and the extraction of soil solutions by suction cups allow a dynamic methodology management in agreement with real crop requirements. This trial was carried out to compare this dynamic fertigation management method (using tensiometers and suction cups) for tomato crops (Lycopersicum sculentum Mill. Forteza) under Mediterranean greenhouse conditions with other methods: the local traditional model, based only on technical consulting, and the classical model, by means of estimation of Kc and nutrient extractions references. The parameters studied were tomato yield, water, and fertilizer amounts applied during the cultivation as well as water- and fertilizer-use efficiency. The water used to prepare the nutrient solution was classified as C₄-S₃ following the Riverside classification system. Plants were grown from 15 August to 20 April. The results show that the supply of fertilizers during the cultivation has been significantly lower with classical and dynamic models. Dynamic method shows greater efficiencies for all the elements, except for potassium, and also decreases the water consumption, not affecting total yield.     

Ecological impacts of small hydropower plants on headwater stream fish: from individual to community effects

Hydroelectricity is increasingly used worldwide as a source of renewable energy, and many mountain ranges have dozens or hundreds of hydropower plants, with many more being under construction or planned. Although the ecological impacts of large dams are relatively well known, the effects of small hydropower plants and their weirs have been much less investigated. We studied the effects of water diversion of small hydropower plants on fish assemblages in the upper Ter river basin (Catalonia, NE Spain), which has headwater reaches with good water quality and no large dams but many of such plants. We studied fish populations and habitat features on control and impacted reaches for water diversion of 16 hydropower plants. In the impacted reaches, there was a significantly lower presence of refuges for fish, poorer habitat quality, more pools and less riffles and macrophytes, and shallower water levels. We also observed higher fish abundance, larger mean fish size and better fish condition in the control than in impacted reaches, although the results were species‐specific. Accordingly, species composition was also affected, with lower relative abundance of brown trout (Salmo trutta) and Pyrenean minnow (Phoxinus bigerri) in the impacted reaches and higher presence of stone loach (Barbatula quignardi) and Mediterranean barbel (Barbus meridionalis). Our study highlights the effects of water diversion of small hydropower plants from the individual to the population and community levels but probably underestimates them, urging for further assessment and mitigation of these ecological impacts.     

可可膳食纤维的制备工艺及物理特性研究

以可可果皮为原料，采用酸水解法提取水溶性膳食纤维和水不溶性膳食纤维。结果表明，可可水溶性膳食纤维的最佳提取工艺为：料液比为1∶30，水浴温度90℃，pH 2.0，提取时间30 min，得率为25.19%。可可膳食纤维总得率达57.99%，不溶性膳食纤维的持水力为5.23 g/g，溶胀性为11.42 mL/g。     

Dispersal and tributary immigration by juvenile coho salmon contribute to spatial expansion during colonisation

Anadromous fishes are frequently restricted by artificial barriers to movement such as dams and culverts, so measuring dispersal helps identify sites where improved connectivity could promote range expansion and population viability. We used a combination of DNA‐based parentage analysis and mark–recapture techniques to evaluate dispersal by juvenile coho salmon (Oncorhynchus kisutch) in a population in the initial stages of colonisation following installation of fish passage structures at a previously impassable dam on the Cedar River, WA, USA. The spatial distribution of individuals within maternal families revealed that dispersal was common. Among the offspring of radio‐tagged mothers, 28% were collected outside the spawning reach and dispersed up to 6.3 km (median = 1.5 km). Most juveniles captured in a tributary (Rock Creek, where few adults spawned) had immigrated from the Cedar River and represented many different families. Juvenile dispersal therefore provided a secondary phase of spatial expansion following initial colonisation by adults. Consistent with the condition‐dependent dispersal hypothesis, juveniles that dispersed farther upstream in the tributary were larger than fish collected near the tributary mouth. Overall, the results demonstrated widespread dispersal in a system with low coho salmon densities, and this might increase the rate of population growth if it reduces the effects of local density dependence. By implication, juveniles can take advantage of rearing habitats reconnected through barrier removal, even when such areas are located several kilometres from adult breeding grounds.