冷却剂参数对铣槽喷管低周疲劳寿命的影响

采用有限体积流固耦合计算方法、非线性有限元热结构耦合分析方法和局部应变法研究大面积比铣槽喷管三维再生冷却槽道在循环工作条件下的热结构变形与低周疲劳寿命,并对比分析了冷却剂质量流量与入口温度对铣槽喷管疲劳使用寿命的影响。计算结果表明,铣槽喷管热结构响应呈现复杂的三维效应,应变较大位置主要分布在与肋连接的内衬区域,喷管中部的残余应变量最大;冷却槽道低周疲劳寿命分布和热结构响应基本一致,最小寿命位于喷管中部与肋相连的内衬区域燃气侧;随冷却剂质量流量增加,铣槽喷管低周疲劳寿命不断提高;随冷却剂入口温度增加喷管尾部低周疲劳寿命值不断降低,而喷管中前部的低周疲劳寿命值却不断提高,当冷却剂入口温度为280K左右时,本文的铣槽喷管总体使用寿命达到最大。      

增补UV-B辐射对药用植物黄檗幼苗生长及光合生理影响

[目的]为了研究紫外辐射对药用植物生长和光合生理影响机制,[方法]通过设置三个实验处理对黄檗(Phellodendron amurense)幼苗进行40d的增补UV-B辐射处理,对照组(CK组)自然光照、T1组为自然光照下增补UV-B辐射强度为3.26 μw.cm_-2.nm_-1,T2组为自然光照下增补UV-B辐射强度为9.78 μw.cm_-2.nm_-1。[结果]结果表明黄檗幼苗在增补UV-B辐射处理后,与对照相比,不同辐射强度下单株生物量增长量显著低于对照组(P<0.05),而根冠比则显著降低(P<0.05),并且二者随辐射强度增大均减小;光合速率、蒸腾速率和气孔导度均显著低于对照(P<0.05),并随辐射强度升高而降低;叶绿素初始荧光(F₀)、最大荧光(Fm)、PSⅡ原初光能转换效率(Fv/Fm)、PSⅡ潜在光化学活性(F_V/F₀)、光化学猝灭系数(qP)和表观电子传递速率(ETR),均随UV-B辐射强度增大而降低(P<0.05),非光化学猝灭系数(qN)在低UV-B辐射强度下升高,随辐射强度增大而又降低,但仍高于对照组(P<0.05)。叶绿素a、叶绿素b、总叶绿素、类胡萝卜素和叶绿素a/b等光合色素含量均随增补UV-B辐射强度增大而降低。[结论]说明UV-B辐射处理抑制了黄檗幼苗的生长,降低了光合色素的含量和PSⅡ反应中心传递电子的能力,导致光合作用强度下降,并且上述作用均具有剂量效应。     

长武塬区土壤热状况变化特征

通过分析长武塬区农田生态系统内的土壤热状况来探讨该系统地气界面的能量传递的过程和特征,为陆面过程及大气边界层的研究提供参考。根据2008年气象观测资料,本研究从反照率、温度梯度、土壤热通量及其与辐射的相互关系等方面进行研究,从而分析土壤热状况月变化特征及其影响因素。研究结果表明：（1）除10~20 cm层外,各层月变化在5月份及6月份上旬最小,11月份下旬到次年2月上旬一直维持在较高水平,且变化不大;（2）土壤热通量月变化趋势与土壤温度表现负相关;（3）反照率在1月份达到年最大值0.66,3-9月份变化不大,在9月份达到最低值0.14;从10月份开始,上升趋势明显,直到次年1月份;（4）在日变化中净辐射持续增强和减弱两个时间段内,同一辐射强度对应的热通量值相差较大,土壤热通量延迟不明显。增强时段的相关性（R12=0.766）小于减弱时段的相关性（R22=0.799）。农田生态系统中土壤热通量和净辐射的相关性远远高于林地,低于草地和稀疏灌层生态系统。     

UV-B辐射增加与酸雨复合处理对菠菜种子 萌发和幼苗生长的影响

研究了UV-B辐射增加与酸雨的复合处理对菠菜种子萌发和幼苗生长的影响。结果表明：UV-B辐射增加与酸雨的复合处理,使菠菜种子的萌发率和幼苗的株高、绿叶数、叶面积、干重呈显著降低趋势;使幼苗叶绿素含量降低、蒸腾速率减小。复合胁迫的下降幅度明显高于单一因子胁迫,并且下降幅度受UV-B辐射强度与酸雨pH的影响。UV-B辐射增加与酸雨处理在影响菠菜种子萌发和幼苗生长上具有协同作用。     

循环通风对白肋烟晾制期间晾房内温湿度的影响

为改进白肋烟晾制技术,利用温湿度自动记录仪定时测量白肋烟晾制期间晾房内的温度和相对湿度,在晾房内加装循环通风风机调控温湿度,分析了白肋烟晾制期间晾房内外的温湿度差异,比较了加装风机循环通风对晾房温湿度的影响。结果表明,晾房内温湿度主要受外界天气的影响,但晾房可缓解外界天气的影响;晾房内温度变化与相对湿度变化呈相反趋势,温度高时相对湿度低,温度低时相对湿度高;晾房内上层温度较下层高,上层湿度较下层低。在晾房内加装风机能够调控晾房内的温湿度状况,可适度减少晾房上层与下层的温湿度差异,但是由于晾房内温湿度主要受外界气象条件影响,仅安装循环风机对降低晾房内相对湿度的效果有限。     

锡林浩特地区太阳紫外辐射极值分析

为了解锡林浩特地区太阳紫外辐射变化规律,并为全球太阳紫外辐射研究提供可靠的基础依据和参考。根据锡林浩特国家气候观象台2007-2009年太阳总辐射与紫外辐射观测资料,笔者运用数理统计学方法,对锡林浩特地区太阳紫外辐射UV-B极值进行分析。结果表明：太阳紫外辐射是太阳总辐射的一部分,日极值出现在12:30左右并且有云的天气。一天内早晚小,中午大,总体变化范围为0.01~3.05 W/m2。年极值只有冬季出现在晴天,春、夏、秋季均出现在有云的天气,最大值出现在7月份为3.05 W/m2。锡林浩特地区紫外辐射日瞬时极值变化和季节变化的主要趋势与太阳总辐射一致,瞬时极值可出现在有云的任何天气条件下,一年四季紫外辐射强度均在安全范围变化。     

UV-B辐射增加对水稻生长发育及产量的影响

在盆栽条件下,以有代表性的2个粳稻品种为试材,采用盆栽方法,研究UV-B辐射对2个粳稻品种生长发育及其产量的影响。试验设3个处理,分别为自然光、紫外辐射增强5%和10%。试验结果表明,UV-B辐射强度增加明显滞后水稻的生育期,使株高变矮,分蘖数减少,叶面积和干物重下降,最终导致产量降低。并且UV-B辐射强度增加后穗粒数和穗数的下降是水稻产量降低的主要原因。总体来说,UV-B辐射增加越多对水稻的影响越大,但其抑制程度依品种,水稻所处的生长阶段的不同而不同。     

基于Landsat8遥感影像的地表温度反演方法对比研究

随着数据的自由共享，Landsat8系列卫星的遥感数据已经成为地表温度反演的重要数据之一。本文基于Landsat8数据的地表温度反演算法，选择大兴安岭地区漠河市作为研究区域。采用基于Landsat8热红外波段的辐射传输模型法、单窗方法、劈窗算法等不同方法对地表温度进行反演，探究高纬度地区地表温度分布规律，并运用野外实测地温数据进行验证。结果表明：针对本研究区的3种地表温度反演的拟合效果都较好，温度误差在1℃左右，其中辐射传输方程法所得结果精度更高，可为高纬度地区夏季地表温度反演与冻土退化等研究提供一定的参考价值。     

红外对流组合干燥小麦试验研究

设计了新型的红外热风组合谷物干燥机。该机采用先红外加热,再以热风对流排湿的干燥工艺。进行了不同对流风温、不同物料移动速度和有无红外辐射涂料为变动因素的小麦干燥正交试验。试验表明,在试验水平内,对流风温110℃、物料移动速度3.5cm/min和有红外辐射涂料时,物料降水幅度较大。试验中对流风温110℃的条件下,物料温度并未超过55℃,这与该机采用的干燥工艺有关。     

发动机燃烧室内壁材料热环境的气动热试验模拟技术研究

利用超声速矩形湍流导管和等离子电弧加热器模拟了发动机燃烧室内流和高超声速飞行器外壁面外流热环境,进行了平板表面冷壁热流测量和燃烧室内壁材料考核试验。结果表明:由于辐射换热的影响,在选取的两个典型来流条件下,发动机燃烧室内流热环境下的冷壁热流比外流热环境下的高出21%和40%,但是冷壁热流的增量基本相当,约为0.70~0.80MW/m²。随着冷壁热流的增加,辐射换热产生的热流增量的影响力会逐渐减小。材料考核时,相同配方的C/SiC复合材料在内流热环境下的表面温度高出约400℃,背面温度高出约90℃,这种差异对于发动机燃烧室内壁面材料考核至关重要,必须在材料考核试验中加以考虑。      

Biological Activity and Quantification of Suspected Allelochemicals from Alfalfa Plant Parts

Autotoxicity restricts reseeding of alfalfa (Medicago sativa L.) after alfalfa until autotoxic chemical(s) breaks down or is dispersed into external environments. A series of aqueous extracts from leaves, stems, roots and seeds of alfalfa ‘Vernal’ were bioassayed against alfalfa seedlings of the same cultivar to determine their autotoxicity. The highest inhibition was found in the extracts from the leaves. Extracts at 40 g dry tissue l^?1 from alfalfa leaves were 15.4, 17.5 and 28.7 times more toxic to alfalfa root growth than were those from roots, stems and seeds, respectively. A high‐performance liquid chromatography (HPLC) analysis with nine standard compounds showed that the concentrations and compositions of allelopathic compounds depended on the plant parts. In leaf extracts that showed the most inhibitory effect on root growth, the highest amounts of allelochemicals were detected. Among nine phenolic compounds assayed for their phytotoxicity on root growth of alfalfa, coumarin, trans‐cinnamic acid and o‐coumaric acid at 10^?3 m were most inhibitory. The type and amount of causative allelochemicals found in alfalfa plant parts were highly correlated with the results of the bioassay, indicating that the autotoxic effects of alfalfa plant parts significantly differed.     

Changes in Seed Yield and Quality with Maturity in Onion (Allium cepa L., cv. 'Early Cream Gold')

Development of onion (Allium cepa L., cv. ‘Early Cream Gold’) seed under cool climate conditions in Tasmania, Australia occurred over a longer duration than previously reported, but similar patterns of change in yield components were recorded. In contrast to previous studies, umbel moisture content declined from 85 to 67 % over 57 days while seed moisture content decreased from 85 to 31 %. Seed yield continued to increase over the duration of crop development, with increasing seed weight compensating for seed loss resulting from capsule dehiscence in the later stages of maturation. Germination percentage was high and did not vary significantly from 53 to 77 days after full bloom (DAF), but mean germination time declined and uniformity of germination increased significantly over the same time period. The percentage abnormal seedlings declined with later harvest date, resulting in highest seed quality at 77 DAF. The results of this study suggest that the decision to harvest cool climate onion seed crops before capsule dehiscence will result in a loss of potential seed yield and quality.     

Location of a high-lysine gene and the DDT-resistance gene on barley chromosome 7

Summary The high-lysine gene in Risø mutant 1508 conditions an increased lysine content in the endosperm via a changed protein composition, a decreased seed size, and several other characters of the seed. The designation lys3a, lys3b, and lys3c, is proposed for the allelic high-lysine genes in three Risø mutants, nos 1508, 18, and 19. Linkage studies with translocations locate the lys3 locus in the centromere region of chromosome 7. A linkage study involving the loci lys3 and ddt (resistance to DDT) together with the marker loci fs (fragile stem), s (short rachilla hairs), and r (smooth awn) show that the order of the five loci on chromosome 7 from the long to the short chromosome arm is r, s, fs, lys3, ddt. The distance from locus r to locus ddt is about 100 centimorgans.     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Simultaneous Determination of Four Phenolic Acids in Radix Salviae Miltiorrhizae Formula Granules by QAMS

[Objectives]This study aimed to establish a QAMS(quantitative analysis of multi-components by single-marker)method for simultaneous determination of four phenol...     

Avoidance of leaf rust fungi in wild relatives of cultivated cereals

Summary Avoidance of rust fungi that was based on poor appressorium induction was previously found in Hordeum chilense. In the present study 95 accessions of Triticeae were screened for avoidance of Puccinia hordei. The percentage of appressorium formation per germinated spore ranged from 6 to 90%. On none of the 41 accessions of Aegilops, Agropyron, Elymus, Secale, Thinopyrum or Triticum studied was the rate of appressorium formation lower than 25%. Lower rates of appressorium formation were, however, found on accessions of wild barley species Hordeum brachyantherum, H. marinum, H. parodii and H. secalinum. Its implications in cereal breeding are discussed.     

Variation in forage grasses as hosts of the root-knot nematode Meloidogyne naasi (Franklin) and selection for resistance in ryegrass

Summary Reactions of 13 grasses to Meloidogyne naasi varied with species; ryegrasses, fescues and their hybrids were generally susceptible and cocksfoot and timothy resistant. Marked variation in host resistance levels occurred between genotypes within cultivars.Selection of single plants, followed by tests on replicate tillers, identified resistant and susceptible genotypes in both Italian and perennial ryegrass cultivars. Resistant plants had few nematode-induced galls and fewer females and eggs than susceptibles. There was more or less continuous variation, with many genotypes intermediate between extremes of resistance and susceptibility. Selected resistant and susceptible genotypes are of use in assessing variation in nematode populations and as controls for breeding and selection programmes.     

Current and future strategies in breeding lentil for resistance to biotic and abiotic stresses

Lentil production is limited by lack of moisture and unfavorable temperatures throughout its distribution. Waterlogging and salinity are only locally important. Progress has been made in breeding for tolerance to drought through selection for an appropriate phenology and increased water use efficiency and in breeding for winter hardiness through selection for cold tolerance.The diseases rust, vascular wilt, and Ascochyta blight, caused by Uromyces viciae-fabae, Fusarium oxysporum f. sp. lentis, and Ascochyta fabae f. sp. lentis, respectively, are the key fungal pathogens of lentil. Cultivars with resistance to rust and Ascochyta blight have been released in several countries and resistant sources to vascular wilt are being exploited. Sources of resistance to several other fungal and viral diseases of regional importance are known. In contrast, although the pea leaf weevil (Sitona spp.) and the parasitic weed broomrape (Orobanche spp.), and to a lesser extent the cyst nematode (Heterodera ciceri), are significant yield reducers of lentil, no sources of resistance to these biotic stresses have been found. Directions for future research in lentil on both biotic and abiotic stresses are discussed.     

Present status and future strategy in breeding faba beans (Vicia Faba L.) for resistance to biotic and abiotic stresses

Progress is being made, mainly by ICARDA but also elsewhere, in breeding for resistance to Botrytis, AScochyta, Uromyces, and Orobanche; and some lines have resistance to more than one pathogen. The strategy is to extend multiple resistance but also to seek new and durable forms of resistance. Internationally coordinated programs are needed to maintain the momentum of this work.Tolerance of abiotic stresses leads to types suited to dry or cold environments rather than broad adaptability, but in this cross-pollinated species, the more hybrid vigor expressed by a cultivar, the more it is likely to tolerate various stresses.     

Water Extraction Process of Chinese Herbal Compound Man Gan Ning

[Objectives]To optimize the water extraction process of Chinese Herbal Compound Man Gan Ning and establish a method for its extraction and content determination...