大宁河龙溪段鱼类早期资源研究

为了解十年禁渔背景下大宁河鱼类早期资源变化状况,2020和2021年5-7月在大宁河龙溪断面开展了鱼类早期资源现状的调查。结果表明,龙溪江段产浮性卵鱼类1种、漂流性卵鱼类4种、粘沉性卵鱼类19种;中华纹胸鮡（Glyptothorax sinensis）和大眼鳜（Siniperca kneri）的产卵规模相对较大,其卵占比分别达48%和30%以上;2020年的鱼类卵苗资源量和种类都少于2021年。RDA分析结果显示,中华纹胸鮡（Glyptothorax sinensis）、张氏?(Hemiculter tchangi)鱼卵漂流密度与水温变化呈现一定相关性,适宜水温促使中华纹胸鮡（Glyptothorax sinensis）、张氏?(Hemiculter tchangi)产卵;随着流速和流量增加,多鳞白甲鱼(Scaphesthes macrolepis)和云南盘鮈(Discogobio yunnanensis)卵漂流密度均相应增加;大眼鳜（Siniperca kneri）和峨眉后平鳅(Metahomaloptera omeiensis)产卵期间江水酸碱度相对较低。十年禁渔的实施对大宁河鱼类资源的恢复可能产生积极影响。     

Effect of repeated laundering and Dry-cleaning on the thermo-physiological comfort properties of aramid fabrics

This research investigated the effect of repeated laundering and dry-cleaning on the physical and thermophysiological comfort properties such as air permeability, water vapour resistance and thermal resistance of fabrics made of meta-aramid (Nomex®) fibre. Two different types of fabric were selected for the study and subjected to repeated laundering and dry-cleaning (1, 5 and 10 cycles), which is commercially used for the care and maintenance of these fabrics. The fabric thickness, areal density, thermal resistance and water vapour resistance values increased with the number of laundering cycles, whereas the air permeability decreased due to the fabric shrinkage and swelling. On the other hand, the thickness and air permeability of the dry-cleaned fabric samples increased with the number of cycles; while the water vapour resistance and thermal resistance decreased. The scanning electron microscopy images showed the structural changes as indicated by the longitudinal fibrillation in the fabrics subjected to laundering or dry-cleaning.     

Investigation of Polymorphisms in Coding Region of OsHKT1 in Relation to Salinity in Rice

Rice(Oryza sativa) is sensitive to salinity, but the salt tolerance level differs among cultivars, which might result from natural variations in the genes that are responsible for salt tolerance. High-affinity potassium transporter(HKTs) has been proven to be involved in salt tolerance in plants. Therefore, we screened for natural nucleotide polymorphism in the coding sequence of Os HKT1, which encodes the HKT protein in eight Vietnamese rice cultivars differing in salt tolerance level. In total, seven nucleotide substitutions in coding sequence of Os HKT1 were found, including two non-synonymous and five synonymous substitutions. Further analysis revealed that these two non-synonymous nucleotide substitutions(G50T and T1209A) caused changes in amino acids(Gly17Val and Asp403Glu) at signal peptide and the loop of the sixth transmembrane domain, respectively. To assess the potential effect of these substitutions on the protein function, the 3D structure of HKT protein variants was modelled by using PHYRE2 webserver. The results showed that no difference was observed when compared those predicted 3D structure of HKT protein variants with each other. In addition, the codon bias of synonymous substitutions cannot clearly show correlation with salt tolerance level. It might be interesting to further investigate the functional roles of detected non-synonymous substitutions as it might correlate to salt tolerance in rice.     

PEG模拟干旱胁迫对筇竹种子萌发的影响

采用不同浓度的PEG-6000溶液,模拟干旱条件,对筇竹进行渗透胁迫处理。结果表明:随着水分胁迫增强,筇竹种子的日相对萌发率、发芽率、发芽势、发芽指数、活力指数均呈下降趋势;低浓度(5%、10%)胁迫可以促进筇竹种子胚根生长,而高浓度(≥15%)则具有抑制作用;与对照相比,随着PEG浓度的增加,筇竹种子初始萌发时间延迟明显,而在PEG浓度达30%时筇竹种子未见萌发;将在PEG浓度为30%条件下未萌发的种子用蒸馏水冲洗干净后,在通常发芽条件下进行发芽试验可以实现复萌。     

亚临界流体萃取高良姜活性物质的工艺研究

采用亚临界流体萃取技术提取高良姜粗提物,所得粗提物再经分子蒸馏技术获得精油和活性物质(以二苯基庚烷类物质为主)。通过气质联用技术及液质联用技术进行质量控制,结果表明：亚临界流体萃取技术所得挥发油提取率(1.513 %)高于传统水蒸气蒸馏法(0.802 %),其中指标成分1,8-桉叶素(0.170 6 %)约等于水蒸气蒸馏法所得(0.172 5 %),高于药典规定的0.15 %;亚临界流体萃取技术所得二苯基庚烷类物质约是常规工艺的4倍。该技术提取效率高,耗能少,开发前景广阔。     

多功能列当生防镰刀菌的筛选及种类鉴定

从河北省张家口地区种植的烟草上采集的感病弯管列当植株,从中分离得到20株镰刀菌,采用孢子悬浮液浸根和灌根法对小麦、玉米、棉花、向日葵、番茄、烟草、辣椒、茄子、西瓜、甜瓜等作物和蔬菜进行了安全性检测,筛选出对主栽作物和蔬菜安全且具有促生作用的4个菌株。其中菌株Br-2对烟草、辣椒、西瓜有显著促生作用,且对弯管列当的防治效果最好：施用菌株Br-2后烟草、辣椒、西瓜增高分别为123.53%、62.16%、28.95%;其发酵上清液对弯管列当种子萌芽抑制率为71.79%;小区试验中对弯管列当的寄生率防效为50%,寄生度防效为79.38%;田间试验中对弯管列当的寄生率防效为58.27%,寄生度防效为75.70%。形态学和分子生物学鉴定结果表明菌株Br-2为尖孢镰刀菌。     

轴流泵多工况优化设计及效果分析

为了提高轴流泵非设计工况的运行效率,拓宽轴流泵高效区范围,对轴流泵进行多工况优化设计。结合轴流泵段的模型试验,采用数值模拟手段和数值优化技术,改变叶轮的几何设计参数。对轴流泵叶片进行参数化建模,再对轴流泵叶轮结果进行泵段数值模拟。最后以轴流泵段3个流量工况点的加权平均效率最高,扬程为约束条件,改变轴流泵叶轮的设计参数,对轴流泵段进行多工况优化设计。研究结果表明:优化后轴流泵段效率曲线较初始泵段明显变宽,其中小流量工况点效率提高约2.6%,设计工况点效率提高约0.5%,大流量工况点效率提高最多,约7.4%,而对于扬程变化范围较小,各工况点扬程均能满足运行要求,大大降低了运行成本,缩短了优化设计的周期。同时采用CFD计算的学科分析方式,结合试验研究的手段取代人工凭经验的优化方式,证实了轴流泵段多工况优化设计的可靠性、高效性。该研究将为泵站的高效运行和轴流泵的多工况优化设计提供参考。     

地膜残留量对新疆棉田蒸散及棵间蒸发的影响

为探讨残膜对干旱区农田蒸散耗水特征的影响,在新疆阿克苏典型覆膜滴灌棉田开展2 a小区试验研究,设计0、225、450 kg/hm2共3种不同的地膜残留量,采用水量平衡法,微型棵间蒸发仪法,于主要生育时期测定并计算土壤含水量、蒸散量、棵间蒸发量、作物蒸腾量、棵间蒸发占蒸散的比例。结果表明:随着地膜残留量增加棵间蒸发量、棵间蒸发占蒸散的比例呈增大趋势,而蒸散量及作物蒸腾量则逐渐减小。与无残膜处理相比,225和450 kg/hm2处理全生育期田间无效耗水的棵间蒸发量分别增加了9.27和22.20 mm,棵间蒸发占蒸散的比例增幅分别为2.6%和6.1%,作物蒸腾量降低34.89和55.94 mm。在棉花生育期内,棵间蒸发占蒸散的比例(E/ET)与叶面积指数(leaf area index,LAI)呈幂函数关系,各处理间棵间蒸发占蒸散的比例对叶面积指数的响应差异不同,450 kg/hm2处理蒸发占蒸散的比例随着LAI的增加,曲线下降趋势较明显;无残膜处理棵间蒸发占蒸散的比例与LAI的决定系数最高,均在0.9以上。土壤水分利用率也随残膜量的增加依次降低,当残膜量由0增加到450 kg/hm2时,土壤水分利用率从28.25%降至24.91%,可见,残膜增大了农田的无效耗水,不利于土壤水分的有效利用。研究可为制定缓解或克服残膜危害的应变调控技术提供依据。     

用于生物降解膜的聚己内酯与聚乳酸共混物制备及性能分析

聚乳酸农用薄膜在自然条件下能够降解为CO2和H2O,可以有效地避免传统农用薄膜废弃后造成的土壤和环境污染。将聚己内酯与聚乳酸共混可以改善聚乳酸脆性强和韧性差的特点。该文将不同质量比例的聚己内酯(polycaprolactone,PCL)和聚乳酸(polylactic acid,PLA)熔融共混后通过注射成型工艺制备了农业薄膜用PCL/PLA共混物,研究了PCL与PLA配比对共混物力学性能、热稳定性、结晶熔融行为以及表面润湿性的影响。结果表明:随着PCL含量增加,共混物的拉伸强度逐渐下降,而拉伸断裂伸长率和冲击强度则先增大后减小。PCL质量分数为50%时,共混物拉伸断裂伸长率和冲击强度分别达到最大值11.2%和6.4 KJ/m2;扫描电镜分析显示,PCL与PLA相容差,聚酯连续相种类及优势共同主导力学性能走向;热重分析表明,PCL的引入有效减缓了共混物热解速率,PLA质量分数增加共混物燃烧成炭率增大;差示扫描量热法分析表明,相对于PCL和PLA,PCL/PLA共混物玻璃化转化温度、熔融温度和结晶温度均产生了变化,但二者配料比对3种温度影响不明显;接触角分析表明,PCL/PLA共混物接触角相比于PCL和PLA均有所增大,水润湿性能不同程度的降低。综合考虑,PCL与PLA最佳质量比为50∶50。研究可为农业薄膜用聚己内酯与聚乳酸共混物的制备提供依据。