脉冲式烟雾水雾机热力雾化水剂农药效果分析

针对脉冲式烟雾水雾机在喷施水雾剂农药时常出现滴液、流液或较大雾滴群等雾化不良现象，通过改装6HYW-60S型脉冲式烟雾水雾机，将药液流量设置成可调的测试装置，设定5个油门开度及4个药液流量，测试了脉冲发动机喷药前后的气流速度、温度及各喷药工况下的雾滴粒径分布。结果表明，在最小的油门启动开度到最大的油门工作开度可调范围内，对应的脉冲发动机燃油消耗率变化范围较小（相对变化13.0%），喷管内对应的气流温度与速度也发生同等程度的变化。喷药时，喷管口处的气流温度与速度发生明显变化，由不喷药时约700℃的高温气流下降为75℃左右的雾滴流，相应的气流速度下降了16%左右；油门开度及药液流量对雾滴流温度的影响非常小，但对雾滴流速度的影响非常明显，油门开度增大，雾滴流速度明显增加，药液流量增大，雾滴流速度明显下降。在各油门开度下，对最小药液流量20L/h的雾化效果均不佳，尤其距喷雾出口较近处存在大量的300μm以上的较大雾滴，这些大雾滴极易跌落至地面，无法有效喷施到目标物上；药液流量增大至40L/h及以上时，各油门开度下的雾滴体积中径均较小，同一工况下各位置点的平均值不超过60μm。热力雾化的雾滴粒径分布曲线不是单一峰值的正态分布形态，常会出现不同中心雾滴粒径的雾滴群，且这些雾滴群的中心雾滴粒径基本保持一致。从喷雾出口喷出的雾滴流中，喷管中心轴线上的雾滴细小均匀、雾化充分，中心轴线上方的雾滴一般比中心点处稍大，中心轴线下方雾滴明显增大，且距中心轴线越远的下方，雾滴增大越明显，即雾滴流中较大雾滴群的量逐渐增加。以药液流量60L/h及油门开度90°为最佳雾化工况，在整个喷施区域内均形成了良好的雾化效果。     

履带拖拉机旋耕机组稳定性仿真分析与试验

针对履带拖拉机旋耕机组在坡道上行驶稳定性问题,利用SolidWorks三维软件建立某型履带拖拉机车体和旋耕机组的三维模型,在多体动力学软件Recurdyn/Track(LM)中建立履带行走装置模型,并建立整机静态稳定性数学模型。针对多体动力学软件Recurdyn/ground模块提供的3种土质路面进行整机稳定性的仿真分析。仿真结果表明,整机在黏土、砂壤土及干沙土最大爬坡角度分别为31°、23°和18°,在黏土、砂壤土的爬坡稳定性高于干沙土;整机在黏土的侧向坡道沿等高线行驶时,土壤附着能力大于砂壤土和干砂土,速度波动最小。最后进行了爬坡稳定性的试验验证。该研究为履带拖拉机旋耕机组行驶稳定性提供重要参考。     

木薯有性四倍体遗传稳定性分析

木薯作为中国重要的经济作物,其优良品种的选育一直是木薯科研工作的重点,而多倍体的巨型性特点为其育种提供了新的思路,目前多倍体研究大多是体细胞加倍,有性多倍化研究起步较晚,而本课题组通过2n配子有性活体杂交,成功获得了首例木薯有性四倍体植株。为了研究木薯有性四倍体的遗传稳定性,本研究分别采用:田间的农艺性状观测(生长稳定期)、流式细胞术、叶片染色体计数、蛋白质含量测定/蛋白质聚丙烯酰胺凝胶电泳以及淀粉含量测定等方法进行鉴定。结果显示:木薯有性四倍体各株系农艺性状均保持了母株器官巨型性的多倍体特征;流式细胞仪分析显示,木薯有性四倍体各株系叶片DNA含量均为二倍体亲本(SC5)的两倍,相对应的叶片染色体数目也为二倍体亲本(SC5)的两倍,且视野中四倍体细胞所占比例均在90%以上;各株系蛋白质含量均小于二倍体对照组,且有性多倍体株系电泳谱带基本相似;在淀粉含量测定中,其各株系淀粉含量均小于对照组,且各株系之间含量波动较小。本研究结果表明木薯有性四倍体植株具有较好的遗传稳定性,对木薯多倍体品种的选育具有重要意义。     

生物质导热系数测量系统设计

随着不可再生能源的日渐枯竭,生物质能源的研究工作受到越来越多的关注。想要充分了解和利用生物质能源,生物质材料的热物性分析必不可少。其中,导热系数表征就是研究的重点内容之一,设计出可靠便捷的测量系统至关重要。笔者以LabVIEW平台为基础,依靠其强大的测控功能,结合3ω法测量原理及具体的实验步骤,设计出一种固液相样品都适用的导热系数测量系统。实验中测量端的铂丝将产生电信号,经前置放大电路被锁相放大器SR830采集,然后通过GPIB接口卡与PC机通讯。其中,上位机LabVIEW的程控交互界面包括了前期准备、信息记录、数据采集和曲线显示4个部分,为研究人员提供了直观、便捷、高效的实验进程帮助。还从测量对象的性质和实验台搭建过程两个方面,分析了可能存在的误差来源。为了验证该导热系数测量系统的可靠性,对常见的生物质液体,包括存在固液相变化的样品,进行了测量实验。测量值与文献参考值比较显示,系统误差小于5%,说明该测量系统具有较高的可靠性和稳定性。     

Metabolic rates from Bluntnose minnow (Pimephales notatus) populations at lower latitudes are more sensitive to changes in temperature than populations at higher latitudes

Predicting the potential effects of changes in climate on freshwater species requires an understanding of the relationships between physiological traits and environmental conditions among populations. While water temperature is a primary factor regulating metabolic rates in freshwater ectotherms, how metabolic rates vary across the species range is unclear. In addition, photoperiod has also been hypothesised to influence metabolic rates in freshwater taxa based on seasonal changes in activity rates. Using an experimental approach, we investigated whether variation in routine metabolic rate (RMR) and sensitivity of RMR to changes in temperature are correlated with local thermal regimes, photoperiods and body mass among ten populations across the geographic range of the Bluntnose minnow (Pimephales notatus), a North American freshwater fish species. Routine metabolic rate data were collected from populations acclimatised to three temperature treatments (9, 18 and 27°C) and correlated with water temperature and photoperiod estimates at collection locations for each population. Routine metabolic rate was negatively correlated with minimum photoperiod at 9°C, negatively correlated with weekly high temperature at 18°C and positively correlated with weekly high temperature at 27°C. Body mass was also a predictor of RMR at each temperature treatment. Thermal sensitivity of RMR was positively correlated with weekly high temperature, indicating that individuals from warmer low latitude populations experienced greater sensitivity of RMR to changes in temperature than individuals from cooler high latitude populations. These results indicate differential responses among populations to variation in temperature and suggest the importance of recognising this variation when characterising responses of freshwater taxa to increases in water temperature.     

木材及木基材料吸湿尺寸稳定性检测方法研究

为实现木材及木基材料吸湿尺寸稳定性横向比较,规范其检测方法,依据现有相关检测标准,借鉴日本工业木材吸湿尺寸稳定性检测方法,结合木质材料特性以及我国的具体情况,提出一种木材及木基材料吸湿尺寸稳定性的检测方法,即以温度20℃、相对湿度65%条件下的材料尺寸为基准,测定在温度40℃、相对湿度为75%和90%的两种吸湿环境条件下的材料尺寸变化。通过该方法对柚木、印茄木、朴木3种不同尺寸的木材和对多层材料、高密度纤维板、普通刨花板3种木基材料的吸湿尺寸稳定性进行测定,以评价该方法的适用性和可行性。结果表明:木材与木基材料试样不超过12 d即可达到吸湿平衡,不同材料尺寸变化率、湿胀系数的大小关系也与实际情况一致。因此木材与木基材料试样均适于用该方法。     

Agronomic performance of winter wheat grown under highly divergent soil moisture conditions in rainfed and water‐managed environments

Even in the temperate climates of Europe, increasing early season drought and rising air temperature are presenting new challenges to farmers and wheat breeders. Sixteen winter wheat (Triticum aestivum L.) genotypes consisting of three hybrids, six line cultivars and two breeding lines from Germany as well as five line cultivars from France, Austria, Slovakia, Hungary and the Ukraine (referred to as “exotic” lines) have been included in this study. The genetic materials were evaluated over three growing seasons under a range of soil moisture regimes at the three North German sites Braunschweig (irrigated and drought‐stressed), Warmse (rainfed) and Söllingen (rainfed). The average grain yields in the twelve growth environments (water regime × season combinations) ranged from 6.1 to 13.5 t ha^?1. The exotic lines showed little evidence of specific phenological adaptation to drought although they are frequently faced with water scarcity in their countries of origin. The hybrids and German lines exhibited higher regression coefficients (b_i) to environmental means than the exotic lines, indicating particular adaptation to favourable growing conditions. The phenotypical correlations of grain yield between the various environments were high, ranging for instance from 0.6 to 0.8 for the irrigated and drought‐stressed environments at Braunschweig. It is thus expected that in the foreseeable future continued selection aiming at high yield potential will suffice as a means to counter the expected increase in droughts.     

长期继代培养的转基因苹果外源基因遗传及表达稳定性分析

为研究长期继代培养的转基因苹果组培苗中外源基因的遗传及表达稳定性，以继代培养9年的7个转GFP(绿色荧光蛋白)基因苹果株系组培苗为试材，分析转基因株系对Kan(卡那霉素)的抗性、DNA水平、转录水平和转录后水平GFP基因的遗传及表达稳定性。结果表明，在7个苹果转基因株系组培苗中均可检测出GFP特异基因片段，并且均可在含有50 mg/L卡那霉素的培养基上正常生长；绝对定量qRT-PCR检测发现，各转化株系GFP基因拷贝数并不相同；利用相对定量qRT-PCR法检测发现7个株系中GFP基因 mRNA表达量有明显差异，同时荧光显微镜下观察各转化株系叶片，绿色荧光强度有明显差异，利用SPSS软件对7个转基因株系中GFP基因拷贝数与GFP mRNA表达量相关性分析结果呈无显著相关性。以上结果表明，外源基因可以在长期继代培养的转基因苹果组培苗中保持其遗传稳定性，但不同转化株系中外源基因的表达量有显著差异，其表达量与拷贝数无显著相关，可能与外源基因在植物基因组中的插入位点有关。     

Oxidative Stability of Common Kilka (Clupeonella cultriventris caspia) Oil Supplemented with Microwave Extracted Ghure (Unripe Grape) Marc Extract

The objective of this study was to evaluate the effect of microwave extracted Ghure (unripe grape) marc extract on common kilka (Clupeonella cultriventris caspia) oil oxidation during accelerated storage. The antioxidant activity of Ghure marc extract was compared with those of α-tocopherol and BHT. The Ghure marc extract significantly reduced the peroxide and p-anisidine value of kilka oil. Even though the effect of Ghure marc extract on reducing the oxidation of kilka oil was similar to the effect of BHT, it was functionally more effective than α-tocopherol. Generally, Ghure marc extract could be considered as a potential source of natural antioxidants, with inexpensive costs, for improving the oxidative stability of kilka oil.

Abbreviations: AA, Antioxidant activity; AOP, Antioxidant power; AV, p-Anisidine value; CUPRAC, Cupric ion reducing antioxidant capacity; DHA, Docosahexaenoic acid; EPA, Eicosapentaenoic acid; FIC, Ferrous ion chelating; GME, Ghure marc extract; FRAP, Ferrous ion reducing antioxidant power; KO, Kilka oil; IP, Induction period; MAE, Microwave-assisted extraction; MUFA, Monounsaturated fatty acid; PUFA, Polyunsaturated fatty acid; PV, peroxide value; PF, Protection factor; RSA, Radical scavenging activity; SFA, Saturated fatty acids; TFC, Total flavonoid content; TPC, total phenolic content TV, totox value.     

Soil aggregation and the stabilization of organic carbon as affected by erosion and deposition

The importance of soil aggregation in determining the dynamics of soil organic carbon (SOC) during erosion, transportation and deposition is poorly understood. Particularly, we do not know how aggregation contributes to the often-observed accumulation of SOC at depositional sites. Our objective was to assess how aggregation affects SOC stabilization in comparison to interactions of SOC with minerals. We determined and compared aggregate size distributions, SOC distribution in density fractions, and lignin-derived phenols from aggregated soil samples at both eroding and depositional sites. The stabilization effect of aggregation was quantified by comparing mineralization from intact and crushed macro-aggregates. Deposition of eroded soil material resulted in carbon (C) enrichment throughout the soil profile. Both macro-aggregate associated SOC and C associated with minerals (heavy fraction) increased in their importance from the eroding to the depositional site. In the uppermost topsoil (0–5 cm), SOC mineralization from intact aggregates was larger at the depositional site than at the eroding site, reflecting the large input of labile organic matter (plant residues) promoting aggregation. Contrastingly, in the subsoil, mineralization rates were lower at the depositional site because of effective stabilization by interactions with soil minerals. Aggregate crushing increased SOC mineralization by 10–80% at the eroding site, but not at the depositional site. The content of lignin-derived phenols did not differ between eroding and depositional sites in the topsoil (24.6–30.9 mg per g C) but was larger in the subsoil of the eroding site, which was accompanied by higher lignin oxidation. Lignin data indicated minor effects of soil erosion and deposition on the composition of SOC. We conclude that SOC is better protected in aggregates at the eroding than at the depositional site. During transport disaggregation and consequently SOC mineralization took place, while at the depositional site re-aggregation occurred mainly in the form of macro-aggregates. However, this macro-aggregation did not result in a direct stabilization of SOC. We propose that the occlusion of C inside aggregates serves as a pathway for the eroded C to be later stabilized by organo-mineral interaction.