基于BP神经网络的人机联合率定SWMM研究

为解决雨洪管理模型(SWMM)在率定过程中参数复杂、过程繁琐等问题。以西宁市某地块为例建立SWMM模型,利用Morris筛选法进行参数灵敏度分析,并根据灵敏度分析的结果进行人工率定;另外利用BP神经网络对模型进行率定,并结合参数灵敏度对其进行优化。对3种率定方案进行分析,结果表明:水文水力模块参数的相对灵敏度基本一致,其中灵敏度较大的参数为子汇水区面积(Area)、不透水率(Imperv)和不透水区洼地蓄积量(Destore-Imperv),并且不同降雨条件下模型参数的灵敏度存在差异。经过优化后的BP神经网络参数率定方法的模型模拟效果最好,纳什系数最大。结合灵敏度优化BP神经网络的人机联合率定方法一方面能提高BP神经网络率定的准确性,另一方面又能提高传统人工率定的效率。     

大型贯流式泵站快速门加速启动过渡过程

为研究大型贯流式泵站机组闸门加速启动过程中的外特性参数变化及流态变化,对灯泡贯流泵机组进行三维建模,采用Fluent软件中的UDF来控制闸门的启动过程,使用铺层法动网格技术来控制闸门处网格生成与消灭,并设定S-A模型作为湍流模型,对灯泡贯流泵机组启动过程进行瞬态数值模拟.计算结果表明:当贯流泵机组快速门以10倍设计速度启动时,机组的转速与流量将以更快的速度达到额定转速与额定流量,同时瞬间最大倒灌流量相比未加速启动时增加了30%.当贯流泵机组处于倒流状态时,靠近轮毂处叶轮叶道压力面的压强呈现出从叶轮进水边向出水边逐渐递增的分布规律.当机组处于零流量的临界状态时,混乱的流态导致压力集中及脱流现象加重,叶轮进水边负压区范围扩大且程度加深.     

播期和密度对马铃薯原种扩繁生长发育及产量的影响

在马铃薯原种生产中,播种密度和播种期对原种繁育的产量、种薯大小等有着明显的影响。选用当地主栽品种大西洋,于2017-2018年在山丹县冷凉区域,同一地点开展不同播期和密度试验。播种选择4月25日、5月5日、5月15日、5月25日和6月5日,种植密度设置60 000、90 000、120 000、150 000和180 000粒/hm ² 5个水平。结果表明,在当地的栽培模式大垄双行覆膜种植下,4月25日-5月15日播种,播种密度为120 000、150 000粒/hm ²,产量在45 285~46 770kg/hm ²,中种薯率在75.3%~79.6%,合格种薯多,均为最高,且此范围产量差异不显著。考虑到节约原原种投入降低成本,生产中优选120 000粒/hm ²的播种密度,在4月25日-5月15日种植,是大西洋原种繁育的最佳选择方案。     

Polymerisation of gluten proteins in developing wheat grain as affected by desiccation

The breadmaking quality of wheat is affected by the composition of gluten proteins and the polymerisation of subunits that are synthesised and accumulated in developing wheat grain. The biological mechanisms and time course of these events during grain development are documented, but not widely confirmed. Therefore, the aim of this study was to monitor the accumulation of gluten protein subunits and the size distribution of protein aggregates during grain development. The effect of desiccation on the polymerisation of gluten proteins and the functional properties of gluten were also studied. The results showed that the size of glutenin polymers remained consistently low until yellow ripeness (YR), while it increased during grain desiccation after YR. Hence, this polymerisation process was presumed to be initiated by desiccation. A similar polymerisation event was also observed when premature grains were dried artificially. The composition of gluten proteins, the ratios of glutenin to gliadin and high molecular weight-glutenin subunits to low molecular weight-glutenin subunits, in premature grain after artificial desiccation showed close association with the size of glutenin polymers in artificially dried grain. Functional properties of gluten in these samples were also associated with polymer size after artificial desiccation.     

国内杜鹃属植物组培快繁技术的研究进展

本文从外植体选择、外植体的灭菌方式、基本培养基的选择、诱导培养基的选择、生根培养基的选择、生根苗的移栽这几个方面归纳总结了国内有关杜鹃属植物组培快繁应用的研究进展,并提出了目前存在问题与发展利用前景。     

Mycobacteriosis caused by Mycobacterium marinum in reared mullets: first evidence from Sardinia (Italy)

Mycobacterium marinum is a slow‐growing non‐tuberculous mycobacterium, and it is considered the most common aetiologic agent of mycobacteriosis in wild and cultured fish. The diagnosis is principally made by histology when positive Ziehl–Neelsen stain granulomas are detected. The aim of this study was to investigate the occurrence of mycobacteriosis in extensively cultured Mugilidae of two lagoons (Cabras and San Teodoro) from Sardinia by the use of histology, microbiology, PCR and DNA sequencing. Nine of 106 mullets examined were affected by mycobacteriosis, and the spleen was the most affected organ. The histology detected higher rate (100%) of infection in spleen than the culture and PCR (75% and 62.5%, respectively). The sequencing of hsp65 gene identified M. marinum as the primary cause of mycobacteriosis in the mullets examined. Mullets affected by mycobacteriosis were mainly fished in the San Teodoro lagoon characterized by critical environmental conditions. Histology remains the most common method in detecting fish affected by mycobacteriosis, and PCR‐based methods are essential for species identification. Our finding are worthy of attention because mycobacteriosis caused by M. marinum in reared mullets was evidenced for the first time in Sardinia, suggesting that this disease may be underestimated also in other cultured fish species.     

蝴蝶兰‘大辣椒’组培快繁技术体系的优化

探索优化蝴蝶兰组培快繁技术体系，以蝴蝶兰‘大辣椒’半木质化花梗为试验材料，研究消毒剂、基础培养基、植物生长调节剂配比及浓度对蝴蝶兰不定芽诱导、增殖和生根过程的影响。结果表明:1）先用2% H₂O₂溶液处理15 min，再用10% NaClO溶液处理10 min，消毒效果良好，花梗污染率低，为26.6%；2）不定芽诱导最适培养基为花宝1号+花宝2号+ 6-BA 3 mg/L+NAA 0.05 mg/L，出芽率为78.9%；3）不定芽增殖最适培养基为花宝1号+6-BA 5 mg/L+NAA 0.05 mg/L，增殖系数为3.60；4）幼苗生根最适培养基为1/2MS+NAA 0.2mg/L，生根率为73.7%。本研究旨在优化‘大辣椒’品种的组培快繁技术体系，为进一步建立蝴蝶兰再生体系和工厂化生产提供技术支持。     

蝴蝶兰‘红天鹅’组织培养及快繁技术

[目的]探索‘红天鹅’花梗的不定芽诱导、丛生芽继代增殖和生根诱导技术。[方法]以蝴蝶兰新品种‘红天鹅’的花梗作为外植体,开展组织培养技术研究。[结果]用0.1%的HgCl2消毒外植体20 min,污染率可降低至27.2%,萌芽率达91.0%;不定芽继代增殖培养的最适培养基为MS+6-BA 6.0 mg/L+NAA 0.1 mg/L+AD 5.0 mg/L+香蕉50 g/L+土豆50g/L+蔗糖30g/L+琼脂7.5 g/L,增殖系数达3.80;最适合的生根诱导培养基为1/2MS+NAA0.4 mg/L+香蕉50 g/L+土豆50g/L+C 1.0 g/L+蔗糖15 g/L+卡拉胶7.0 g/L,生根时间为15 d,生根率达100%。[结论]发现了适宜‘红天鹅’的从消毒到增殖,再到生根中各试剂和激素的合理用量,为蝴蝶兰快繁技术发展提供了参考。     

桉树人工林中433MHz信道LoRa信号的传播特性

LoRa技术是最新出现的一种无线通信技术,具有低功耗、距离远、工作在非授权波段等特点,与ZigBee等现在常用的无线通信技术相比,其在人工林无线传感器网中更具潜力。然而由于LoRa的传输受环境影响较大,目前在人工林中传播特性的研究还处于空白。本研究基于Shadowing信号衰减模型,在广西东门林场中测试了433 MHz信道LoRa信号在两种天线高度下(1.5,2.0 m)和3种不同环境下(开阔环境、3 a林龄桉树人工林,5 a林龄桉树人工林)LoRa信号接收强度(RSSI)随距离变化的情况,每种条件下得到了两组数据。首先利用其中一组数据对模型进行拟合,拟合结果表明,LoRa信号传输遵从Shadowing模型,拟合度在0.886~0.982。然后利用另一组数据对模型的精度进行验证,验证结果表明,模型精度较高,模型的精度介于0.780~0.961。最后分析了桉树人工林中影响LoRa信号传输的主要因素。本研究的方法和获得的信号衰减系数可以为桉树人工林无线传感器网络监测中LoRa节点的组网和部署提供依据和参考。     

重要经济竹种快繁技术

对中国云南、福建、浙江、重庆、四川、广东等地竹种进行了调查，选择当地主产具有重要经济价值的竹子开展组培快繁技术试验研究。结果表明：1）16个竹种在主产地具有较高的经济效益；2）组培外植体以播种苗枝条为最佳，其次依次为种子、无性繁殖苗枝条、成年竹枝条；3）16个竹种的组培效果表现为：马来龙竹 > 麻竹 > 绿竹 > 龙竹 > 香糯竹 > 巨龙竹 > 高氏甜龙竹 > 勃氏甜龙竹 > 版纳甜龙竹 > 筇竹 > 金佛山方竹 > 云南方竹 > 苦竹 > 毛竹 > 雷竹 > 中华大节竹；4）16个竹种组培苗的造林效果表现为：马来龙竹 > 龙竹 > 麻竹 > 高氏甜龙竹 > 勃氏甜龙竹 > 巨龙竹 > 绿竹 > 版纳甜龙竹 > 香糯竹 > 毛竹 > 雷竹 > 中华大节竹 > 金佛山方竹 > 云南方竹 > 苦竹 > 筇竹。组培技术的应用极大促进了重要经济竹种的繁殖推广。