黄光萎凋对红茶品质的影响

在萎凋过程利用黄光照射茶叶,分析黄光处理对红茶品质的影响。结果表明,黄光照射处理对红茶的外形和汤色品质影响较小,香气和滋味品质显著提高,香气的甜度以及滋味的鲜爽度和甜度显著提高。理化分析结果表明,除多酚和可溶性糖外,黄光处理对红茶的儿茶素、茶黄素、氨基酸和香气成分的影响较显著。红茶经过黄光处理后,其儿茶素总量提高21.6%、茶黄素含量提高17.6%、氨基酸含量提高6.8%,香气总量增加21.7%,而醛酮类和烷烯烃类变化较小。     

利用同框敲除技术研究Ⅲ型聚酮合酶基因orf18的代谢产物

为了阐明Streptomyces sahachiroi ATCC 33158中Ⅲ型聚酮合酶基因orf18的功能,利用同源双交换的方法对该基因进行同框敲除,采用异位表达的方法进行了相应的回补实验。通过高效液相色谱及液相色谱-质谱联用分析发现基因orf18的敲除会明显降低发酵产物中苯甲酸盐的含量,回补该基因能够在一定程度上恢复苯甲酸盐的产量,表明orf18在原宿主中极有可能参与苯甲酸盐的生物合成。     

膜下滴灌旱种水稻适应品种及其评价指标的筛选

为筛选适宜寒地膜下滴灌旱种的水稻品种,明确膜下滴灌旱种水稻农艺性状及品质性状适应性评价指标,以94份寒地早粳稻为材料,采用随机区组试验设计,利用膜下滴灌旱种适应性系数、膜下滴灌旱种适应性指数和综合适应能力,结合主成分分析方法对水稻旱种适应性进行综合评价。结果表明:长白15号、长白17号、吉旱1号和农大1025在膜下滴灌旱种适应性系数、膜下滴灌旱种适应性指数和综合适应能力上均表现为中度或高度适应。水稻农艺性状和品质性状对膜下滴灌旱种适应性反应指数综合评价表明,理论产量、穗数、经济系数、成粒率和千粒重5个因子可作为膜下滴灌旱种水稻农艺性状适应性评价指标,精米粒长、精米率、精米长宽比、蛋白质含量和粗脂肪含量5个因子可作为膜下滴灌旱种水稻品质性状适应性评价指标。     

注射液中非法添加地塞米松磷酸钠UPLC-PDA检查方法的建立

本试验建立了鱼腥草、柴胡、维生素C、盐酸林可霉素、黄芪多糖等注射液中非法添加地塞米松磷酸钠的超高效液相色谱检查方法。采用Waters ACQUITY UPLC^® BEH C18色谱柱（2.1 mm×50 mm,1.7 μm）,以0.75%三乙胺溶液（磷酸调节pH 3.0）-甲醇-乙腈（50：45：5）为流动相,流速0.3 mL/min,二极管阵列检测器,波长采集范围为190~400 nm,记录色谱图波长242 nm,柱温25℃,进样量10 μL。地塞米松磷酸钠质量浓度在10.0~200.0 mg/L内峰面积呈良好线性关系（R²=0.9999）,在鱼腥草、柴胡、维生素C、盐酸林可霉素、黄芪多糖等注射液中地塞米松磷酸钠的平均回收率和相对标准偏差（RSD）分别为97.54%和1.14%、101.59%和0.19%、100.92%和0.92%、99.82%和0.73%、100.08%和0.62%。本方法简单、快速、灵敏、可靠,适用于鱼腥草等5种注射液中非法添加地塞米松磷钠的检查。     

Isolation,production and in vitro effects of the major secondary metabolite produced by Trichoderma species used for the control of grapevine trunk diseases

Antibiosis has been shown to be an important mode of action by Trichoderma species used in the protection of grapevine pruning wounds from infection by trunk pathogens. The major active compound from Trichoderma isolates known to protect grapevine pruning wounds from trunk pathogen infection was isolated and identified. The compound, a 6‐pentyl‐α‐pyrone (6PP), was found to be the major secondary metabolite, by quantity, which accumulated in the culture filtrate of T. harzianum isolate T77 and the two T. atroviride isolates UST1 and UST2. Benzimidazole resistant mutants generated from these isolates also produced 6PP as their main secondary metabolite, except for a mutant of T77 that had lost its ability to produce 6PP. The isolates UST1 and UST2 were co‐cultured with the grapevine trunk pathogens Eutypa lata and Neofusicoccum parvum in a minimal defined medium and a grapevine cane‐based medium (GCBM). Co‐culturing UST1 with N. parvum induced 6PP production in the minimal defined medium and the GCBM. The production of 6PP by UST2 was induced in the GCBM, while co‐culturing with the two trunk pathogens either reduced or had no effect on 6PP production. Mycelial growth and ascospore/conidia germination of E. lata, N. australe, N. parvum and Phaeomoniella chlamydospora were inhibited by 6PP in a concentration‐dependent manner. The results show that the presence of N. parvum and grapevine wood elicits the production of 6PP, suggesting that this metabolite is involved in Trichoderma–pathogen interactions on grapevine pruning wounds.     

不同时间尺度上枣树树干液流的变异特性

为探寻枣树树干液流在不同深度和不同方位的变异特性,提高黄土丘陵区枣树蒸腾耗水量研究精度,在陕西省米脂县远志山红枣试验示范基地采用热扩散式探针(TDP)分别研究了枣树不同方位和不同深度的树干液流速率。结果表明:(1)不同方位探针监测结果间存在差异,研究时间尺度不同,各方位监测结果间的差异显著性不同,差异显著性大小表现为时尺度日尺度月尺度。(2)不同深度探针监测结果间存在差异,随研究时间尺度的不同,不同深度探针监测结果间的差异显著性不同,差异显著性大小表现为时尺度日尺度月尺度。(3)在树干北侧和深度为20 mm的TDP监测值计算生育期耗水量更准确。     

三板拼接式小型U形混凝土衬砌渠道冻胀破坏力学模型

研究土体冻胀对渠道混凝土衬砌结构的影响,对于保障季节性冻土地区渠道输水效率具有重要意义。以三板拼接式小型U形渠道混凝土衬砌结构为对象,研究其在冻胀作用下的受力状态。依据叠加原理将冻胀视为重力、切向冻结力、法向冻结力及法向冻胀力的共同作用,利用结构整体及局部的平衡关系,根据渠道的结构型式、破坏特征及原型观测结果,建立了衬砌结构的冻胀破坏力学模型,给出了便于设计应用的计算公式。对野外观测中的某渠道各部位内力计算结果表明,三板拼接式小型U形渠道混凝土衬砌结构以压弯为主,与实际破坏特征相吻合。刚性接缝处承受较大的轴力和剪力,是结构受力的薄弱位置。为减轻冻胀破坏程度,进一步建议衬砌板直线段倾角α在[22,26]度间取值,坡板弧段圆心角θ略大于U形渠底圆心半角,法向冻结力的合力作用点为从渠顶沿直线段向下2/3处。研究结果可以为季冻区三拼式小型U形混凝土衬砌渠道的设计提供参考依据。     

小型涡流室柴油机供油与燃烧系统协同匹配

小型涡流室柴油机的供油与燃烧系统优化是满足不断加严排放法规的基础。该文以某170F涡流室柴油机为研究对象,运用模拟计算与试验结合的方法,对其供油及燃烧系统开展研究。借助工程软件构建了供油系统仿真模型,通过设计长型短结构喷油器、优化供油系统参数,来提高喷油压力和优化喷油特性;利用FIRE软件对燃烧过程进行模拟,找出了喷油油线在涡流室内位置及燃烧室容积比的最佳范围。柴油机优化后整机初次试验气体比排放低于国家第三阶段排放限值,CO和HC+NOX分别较原机下降了72.8%和21.3%(八工况循环),标定工况烟度由原机4.5下降到1.2 BSU,有效燃油消耗率较原机下降了约16.1%。该研究工作为小型涡流室柴油机性能提高和节能减排提供了参考。     

Impacts of parasites on marine survival of Atlantic salmon: a meta‐analysis

Parasites can, in theory, have large impacts on the survival of fish populations. One method to evaluate such impacts on anadromous species is to apply manipulative field experiments in which parallel groups of antiparasitically treated and non‐treated fish are simultaneously released and then subsequently recaptured as returning adults. A systematic review and meta‐analysis on all such Norwegian studies on Salmo salar provided a data set for the time period 1996 to 2011 on 118 release groups comprising 657 624 fish released and 3989 recaptured. The overall risk ratio (RR) was estimated to be 1.18 (95% CI: 1.07–1.30). The effect varied strongly between groups, (Higgins I² = 40.1%). Over 70% of this heterogeneity could be explained by the release location, time period and baseline survival. The most important predictor variable was baseline survival. In groups with low recapture in the control group (low baseline survival), the effect of treatment was high (RR = 1.7), while in groups with high recapture in the control group (high baseline survival), there was no effect of treatment (RR ~ 1.00). The most prevalent parasite in the region affected by the drugs administered was Lepeophtheirus salmonis. Hence, the meta‐analysis supports the hypothesis that L. salmonis contributes to the mortality of S. salar during outward migration. However, the effect of treatment was not consistent, but was evidently strongly modulated by other risk factors. The results suggest that the population‐level effects of parasites cannot be estimated independently of other factors affecting the marine survival of S. salar.     

基于环境水力学的产漂流性卵鱼类早期资源量估算方法改进

针对鱼类早期资源量估算方法误差大的问题,基于环境水力学,建立鱼卵移流扩散的瞬时点源二维模型,并对模型进行参数选取、守恒验证,分析了鱼类早期资源量传统估算方法的误差,提出一种新的基于环境水力学的产漂流性卵鱼类早期资源量估算方法。结果表明,中心产卵群体,从产卵点到下游约80 km范围内的断面,鱼卵密度呈钟形分布,由传统方法估算得到的早期资源量低于真实值,最大误差为17.5%;对于近岸产卵群体,从产卵点到下游约200 km范围内的断面,鱼卵密度随距离增加呈指数下降,由传统方法估算得到的资源量高于真实值,最大误差为-33.9%;当断面鱼卵密度均匀分布,即中心产卵和近岸产卵时,产卵场下游80 km和200 km后的断面鱼卵密度沿断面分布均匀,传统方法估算结果较为准确,不必进行校正。改进的估算方法可用于计算产漂流性鱼卵的鱼类早期资源量。