番茄果实与空气间对流换热研究

为了摸清番茄果实与空气间传热的对流换热系数,在人工气候室控温、控光环境下,测定了番茄果实不同风速时的表面温度与空气温度的温差,根据热平衡原理计算番茄果实表面的对流换热系数。用Porter和Mitchell模式计算对流换热系数,并计算了模式的回归系数。用称重法测定1 d中番茄果实水分损失量,分析了番茄水分损失产生的潜热交换量。结果表明,采样后24 h内番茄果实水分蒸发产生的潜热交换量平均为2.3 W/m2;番茄果实的对流换热系数随风速增加而线性增加。Porter的模式回归系数修正后,可用Porter公式计算对流换热系数。这为以后的对流传热分析提供了较为确切的热物性参数。     

地铁用间接蒸发冷却器换热性能影响因素

为解决地铁站冷却塔设置难题,提出了一种采用低速电机驱动旋转布水装置的间接蒸发冷却器,在两种布置方式下,对其换热性能进行了单因素实验,并运用正交实验法对较优布置方式下影响换热器换热的因素进行了分析。结果表明：两种布置方式下,喷嘴与蒸发冷却器的间距、两组换热管束间距均存在最佳值,喷嘴双侧旋转布水优于单侧旋转布水;换热器平行气流布置且喷嘴双侧旋转布水为较优布置方式,此时,换热器换热量随喷水量、转速、空气速度、冷却水进口温度的增加以及喷水温度、空气温度的降低而增大,其中,冷却水进口温度对换热器换热影响最为显著,其他因素对其换热的影响从主到次顺序为：喷水量、空气温度、空气速度、喷水温度、转速、冷却水流量。     

冬季供暖工况下混凝土辐射顶板传热特性

针对冬季供暖工况下混凝土辐射顶板的传热问题,建立顶板辐射供暖的简化数学模型,利用MATLAB软件计算其供热量,并通过该顶板辐射供暖的热工特性实验验证模型的合理性。研究表明:顶板温度计算值与实验结果的误差在5.01%以内,供热量计算值与实验结果的误差在5.15%左右。通过对实验和计算结果的分析发现:在定流量稳态工况下,顶板温度随供水温度的增大呈指数性增大,随换热盘管间距的增大而减小。     

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。     

畦灌变量表施尿素条件下水肥运动模拟

[目的]针对畦灌传统表施方式下施肥分布不均的现象,开展了不同变量表施条件下水肥运动模拟以制定合理灌水施肥方案,提高灌水施肥质量。[方法]以畦灌的地表水流运动方程、溶质运移的对流—弥散方程为基础,建立畦灌表施尿素条件下地表水流中溶质浓度变化模型,根据该模型拟合变量参数计算尿素随水入渗量,对3种不同表施条件下(直线递减型、抛物线递减型、均匀分布型)水肥运动进行模拟,并分析其规律。[结果]结果表明,尿素浓度与入渗时间的幂函数模型相关参数受地表撒施分布规律影响,初始浓度变化越大,参数变化幅度越大；不同表施尿素条件下施肥均匀性：直线递减型>均匀分布型>抛物线递减型。[结论]表施方式对畦灌水肥运动有显著影响,可通过制定适宜的变量撒施方式提高灌水施肥质量。     

温度对棉纤维强度及超分子结构的影响

利用短季棉中棉所16号品种, 研究了温度对棉纤维断裂比强度与超分子结构的影响, 结果 表明： 纤维断裂比强度随铃龄增大而升高; 相同铃龄随温度下降断裂比强度降低。 较高 温度条件下α角随铃龄增大不断宽化(变大), 对纤维强度提高不利; 较低温度条件下α角 随纤维发育不断变小(优化), 某种程度上有利于纤维强度提高;     

Experimental analysis of interface thermal contact resistance between steel and concrete

火灾条件下钢管与混凝土间界面热阻对结构温度场有很大影响。利用INSTRON 8874型高温材料试验机的高温接触热阻试验装置对钢-混凝土界面接触热阻进行了试验研究,根据各测点的温度时间历程曲线,利用多项式拟和方法外推得到钢、混凝土界面处温度值,通过热传导方程和接触热阻定义得到了界面接触热阻。试验结果表明,不同界面压力下钢管混凝土界面的接触热阻数值比较稳定,与文献结果相比有一定可靠性;无界面压力下钢管混凝土界面的接触热阻数值离散性大,随温度变化明显。     

IPGphorTM等电聚焦加样方法的改进与电泳结果的预测

固相pH梯度干胶条等电聚焦电泳技术因其分辨率高而成为当今双向电泳分离蛋白质的首选技术,但其实验步骤多难度大,要求试剂配制精确,各项操作无误。通过改变蛋白质加样方法,测定固相pH梯度干胶条IEF电泳过程中的前期水化干胶条时初始电流与终电压的内在规律,发现在不同的样品和不同的设定电压条件下初始电流的变化与IEF电泳终电压结果存在着高度的相关性,水化干胶条时的初始电流与终电压亦存在着高度的相关性。将IEF电泳的水化初始电流值(1μA)作为蛋白质等电聚焦判断标准,指导实验。其方法实用简便,可提高工作效率。     

面包质构特性测定方法的研究（Ⅴ）——压缩程度和压缩速度对面包硬度测定值的影响

用优质面包专用粉制作的面包样品进行质构测定,通过单因素实验重点考察了面包质构测试条件的压缩程度和压缩速度对面包硬度测定值的影响。结果表明：在本研究实验条件下,不同压缩速度的面包硬度测定值有高度显著差异,并且在不同压缩程度条件下都存在随着压缩速度的增大、面包硬度测定值呈先增后减再增大的趋势和规律。面包硬度测定值的变异系数为5.97%~8.65%,各压缩速度下压缩程度大的面包硬度测定值的变异系数相对较小,压缩速度为100 mm/min时、25%、35%及50%压缩程度的面包硬度测定值的变异系数都较小。面包质构测试参数以设置压缩程度50%、压缩速度100 mm/min,取25%压缩程度的硬度测定值为合适。     

水流对鱼类游泳行为和生理代谢的影响的研究进展

为掌握适合鱼类生长的水流条件,对国内外现有的鱼类在不同水流条件下的行为特征及生理代谢进行了系统性的回顾,分析了水流对水质的影响,对比了不同鱼类受水流刺激导致的行为上的差异,并从鱼类生理代谢角度分析了水流对鱼类的影响。结果表明：鱼类能够承受的最大流速一般与体长(Body length, BL)有关,较低的水流速度(<0.5 bl/s)对鱼类无显著性影响,较高的水流速度(>2 bl/s)对鱼类的行为、存活率和生理代谢产生较大的负面影响,而中等的水流速度(0.5～2 bl/s)适合鱼类的生长,能够提高鱼体免疫力,增强鱼体抗氧化水平。针对当前鱼类耐受流速的研究进行展望,从实验角度进行优化,以期获得更加准确的生长-流速曲线。     

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.     

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...     

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...     

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.     

Pollen and pollination experiments. III. The viability of apple and pear pollen as affected by irradiation and storage

Summary Apple and pear pollen was irradiated with doses of 0, 50, 100, 250 and 500 krad (gamma rays) and stored at 4°C and 0–10% r.h. From the in-vitro germination percentages an average LD 50 dose of about 220 krad was estimated. For both irradiated and untreated pollen a close and corresponding lineair relationship existed between germination percentage and pollen tube growth.Irradiated pollen was much more sensitive to dry storage conditions than untreated pollen, resulting in less germination and more bursting. Apparently, irradiation caused the pollen cell membrane to lose its flexibility faster than normal. Rehydration of dry-stored, irradiated pollen in water-saturated air restored germination percentages up to their initial levels. The importance of this procedure in germination trials is stressed.     

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and ortho...     

Cytoplasmic male sterility,resistance to gall mite and mildew,and season of leafing out in black currants

Summary Cytoplasmic male sterility (cms) is described in the F₁ hybrids Ribes × carrierei (R. glutinosum albidum × R. nigrum) and R. sanguineum × R. nigrum. In backcrosses to R. nigrum, progenies with R. glutinosum cytoplasm were either all male sterile, or segregated for full male fertility (F) and complete (S) and partial (I) male sterility. Ratios of F:I+S suggested that two linked genes controlled cms, F plants being dominant for one (Rf ₁) and recessive for the other (Rf ₂).Segregation for cms in relation to three linded genes, Ce (resistance to the gall mite, Cecidophyopsis ribes), Sph ₃(resistance to American gooseberry mildew, Sphaerotheca mors-uvae) and Lf ₁(one of two dominant additive genes controlling early season leafing out) indicated that Rf ₁and Rf ₂were in this linkage group. The gene order and approximate crossover values appeared to be: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXafv3ySLgzGmvETj2BSbqef0uAJj3BZ9Mz0bYu% H52CGmvzYLMzaerbd9wDYLwzYbItLDharqqr1ngBPrgifHhDYfgasa% acOqpw0xe9v8qqaqFD0xXdHaVhbbf9v8qqaqFr0xc9pk0xbba9q8Wq% Ffea0-yr0RYxir-Jbba9q8aq0-yq-He9q8qqQ8frFve9Fve9Ff0dme% aabaqaciGacaGaamqadaabaeaafaaakeaacaWGdbGaamyzamaamaaa% baGaaiiiaiaacccacaGGWaGaaiOlaiaacgdacaGG0aGaaiiiaiaacc% caaaGaaiiiaiaacccacaGGGaGaamOuaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaaccdacaGGUaGaaiOmaiaacs% dacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaaaacaWGsbGaamOzaSGa% aGOmaOWaaWaaaeaacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccaaaGaamitaiaadAgaliaaigdakmaamaaa% baGaaiiiaiaacccacaGGGaGaaiiiaiaacccacaGGGaGaaiiiaiaacc% cacaGGGaGaaiiiaiaacccacaGGGaaaaiaadofacaWGWbGaamiAaSGa% aG4maaaa!6E4D!\[Ce\underline { 0.14 } Rf1\underline { 0.24 } Rf2\underline { } Lf1\underline { } Sph3\]. Crossover values of 0.36 for Ce-Lf ₁, and 0.15 for Lf ₁-Sph ₃were estimated from the relative mean differences in season of leafing out between seedlings dominant and recessive for Ce and Sph ₃.It is suggested that competitive disadvantage of lf ₁-carrying gametes and/or zygotes at low temperatures may be implicated in the almost invariable deficit of plants dominant for the closely linked mildew resistance allele Sph ₃. Poor performance of lf ₁- (and possibly lf ₂-) carrying gametes and young zygotes during periods of low temperature at flowering might also account for the liability of some late season cultivars and selections to premature fruit drop (running off).     

Screening techniques and sources of resistance to parasitic angiosperms

Parasitic angiosperms cause great losses in many important crops under different climatic conditions and soil types. The most widespread and important parasitic angiosperms belong to the genera Orobanche, Striga, and Cuscuta. The most important economical hosts belong to the Poaceae, Asteraceae, Solanaceae, Cucurbitaceae, and Fabaceae. Although some resistant cultivars have been identified in several crops, great gaps exist in our knowledge of the parasites and the genetic basis of the resistance, as well as the availability of in vitro screening techniques. Screening techniques are based on reactions of the host root or foliage. In vitro or greenhouse screening methods based on the reaction of root and/or foliar tissues are usually superior to field screenings and can be used with many species. To utilize them in plant breeding, it is necessary to demonstrate a strong correlation between in vitro and field data. The correlation should be calculated for every environment in which selection is practiced. Using biochemical analysis as a screening technique has had limited success. The reason seems to be the complex host-parasite interactions which lead to germination, rhizotropism, infection, and growth of the parasite. Germination results from chemicals produced by the host. Resistance is only available in a small group of crops. Resistance has been found in cultivated, primitive and wild forms, depending on the specific host-parasite system. An additional problem is the existence of pathotypes in the parasites. Inheritance of host resistance is usually polygenic and its transfer is slow and tedious. Molecular techniques have yet to be used to locate resistance to parasitic angiosperms. While intensifying the search for genes that control resistance to specific parasitic angiosperms, the best strategy to screen for resistance is to improve the already existing in vitro or greenhouse screening techniques.