低压管道环状管网水力计算

本文对环状管网运行中仅开启一个出水口的水力计算方法进行了探讨。计算出了特征长度系数、平均特征长度系数和最大特征长度系数,并将其排成数表供直接查用。同时计算出了双环管网平均和最大特征长度系数的回归方程,经比较,本文提出的计算方法简单、可靠,便于设计中应用。     

A pollen extender medium technology for seedless watermelon production by pollination with soft X-ray irradiated pollen

The inactivation of pollen by soft X-ray irradiation and subsequent artificial pollination are time-intensive practices used in the production of seedless watermelons (Citrullus lanatus L.). Watermelon generally has a lot of staminate flowers; however, they only have a small amount of pollen. Watermelon pollen cannot be used in pollination under the present situation. Therefore, the objective of this study was to determine which is the most effective pollen extender medium for cultivation of watermelon with soft X-ray irradiated pollen. In this experiment, ‘Agar,’ ‘Marriage powder,’ and ‘Sekishoshi’ (Lycopodium dyed red with safflower pigment) were used as extender media with soft X-ray irradiated pollen at equal or twice the weight of the pollen. When ‘Sekishoshi’ was used as an extender medium, fruit set was very low. A lot of deformed fruit was produced when agar was used with the pollen. On the other hand, when ‘Marriage powder’ was used in equal proportions with the pollen, fruit set was about 70% and, moreover, Brix was high. Thus, the mixture of ‘Marriage powder’ with an equal amount of pollen was the best for use in actual cultivation. We conclude, then, that soft X-ray irradiated pollen in an extender medium can be effectively adapted for producing seedless watermelons.     

金光杏梅叶面积回归测算研究

以金光杏梅成熟叶片为试材,研究了叶长、叶宽与叶面积的关系.结果表明:叶长、叶宽与叶面积均呈正相关关系.叶长、叶宽与叶面积之间的相关系数分别为0.7084、0.8546,叶长和叶宽与叶面积的复相关系数为0.9868,在0.01水平下均达到了极显著水平.在此基础上建立了叶长(x1)、叶宽(x2)、叶长和叶宽与叶面积(y)之间的回归方程y=61.4140x1-2 480.6、y=28.7600x2-0.8546、y=17.6276x1+41.2594x2-1 078.4906,3个回归方程均可用于测算金光杏梅的叶面积,其中以叶长和叶宽与叶面积的二元回归方程测算结果更为精确.在具体应用中,可根据所要求的精确度进行选择.     

潜水泵扩张式喷嘴排液装置的优化设计与试验

针对泄漏液体严重危及潜水泵安全的问题,在原非扩张式喷嘴排液装置的基础上,优化设计了一种具有扩张式喷嘴的在线排液装置.为了比较分别具有扩张式和非扩张式喷嘴的排液装置性能的优劣,设计了这两种形式的喷嘴,并设计了4种不同尺寸喉嘴距及6种不同尺寸混合管直径的排液装置;对各种不同的排液装置在同一试验台上分别进行了试验.试验结果表明,当排液装置的扬程为6 m时,具有扩张式喷嘴的排液装置具有更好的排液性能,其最佳工作压力为0.3 MPa,最佳喉嘴距为1.67倍喷嘴喉部直径之长度,最佳混合管直径为2倍喷嘴喉部直径.与非扩张式喷嘴排液装置相比较,具有最佳尺寸的扩张式喷嘴排液装置可以更好地解决潜水泵液体泄漏问题.     

Jackknife method for estimating the variance of the age composition using two-phase sampling with an application to commercial catches of swordfish (Xiphias gladius)

An estimate of the age composition of a commercial swordfish catch and its variance was obtained using the replicate full jackknife estimator for two-phase sampling where the sampling units in the first phase are clusters (vessel-trips) and the units of the second phase are individual fishes. The jackknife variance estimator was compared with an analytical estimator of variance commonly used in fisheries studies which ignores the clustering, and assumes simple random sampling of individual fish. The application of these naïve estimators to the Chilean South Pacific swordfish fishery results in an underestimation of the variance. This is a consequence of using an inappropriate primary sampling unit of analysis in the first-phase sample where the vessel-trip unit is replaced by an individual fish unit, thus ignoring the intra-cluster correlation in age samples. The jackknife estimator of variance is an alternative useful for complex two-phase sampling designs.     

育珠期三角帆蚌的生长及其与珍珠增长的关系

通过对三角帆蚌壳长、壳宽、蚌总重（整体湿重）、内脏团湿重、壳重和珍珠重等指标在5-11月间的逐月连续测定,研究了常规养殖模式下育珠期2龄三角帆蚌在主要生长季节的生长规律及其与珍珠生长的相关性。结果表明：珍珠重(PW)与壳长(SL)、壳宽(SW)的关系分别为PW=0.0008SL3.3946 (R2=0.6948)和PW=0.7809SW1.0227 (R2=0.6888);而珍珠重(PW)与蚌重(TW)、内脏团重(BW)和壳重(W)的关系分别为PW=0.0021TW1.5434 (R2=0.7337),PW=0.107BW0.9125 (R2=0.7158)和PW=0.0324W1.1259 (R2=0.7101);三角帆蚌总重(TW)与壳长(SL)、 壳宽(SW)的关系最适合用指数函数进行拟合,其关系式分别为TW=16.003e0.1681SL,(R2=0.7961),和TW=64.311e0.1372SW (R2=0.6822);而内脏团重(BW)和壳重(W)与壳长(SL)、壳宽(SW)的关系则适合为幂函数曲线拟合,关系式分别为BW=0.0188SL3.1427,(R2=0.6927);W=0.0656SL2.7721, (R2=0.8271)和BW=12.446SW0.8974 (R2=0.617);W=19.876SW0.802 (R2=0.7563)。本研究结果发现,珍珠生长与蚌总重、壳长和壳宽等外部测量指标之间的相关性显著,从而无须通过杀蚌取珠而直接通过这些外部生长指标的测定就能较好地了解珍珠的生长,更好地为珍珠养殖生产和管理提供指导。     

微波杀青对茶在制品物理特性影响的初探

以一芽一叶的福鼎大白茶鲜叶为原料,设定6个微波杀青的时间梯度(0、30、60、90、120、150 s),按时间点取样,测定在制品的含水率、容重、色差Lab值、长度、宽度等,研究微波杀青时间对茶在制品物理特性的影响。结果表明,随着微波杀青的进行,在制品的含水率在前90 s匀速缓慢下降,而后急速下降,容重在微波30 s后显著下降;茶在制品的平均相对长度差、相对宽度差和面积差呈现先降后升的趋势,在微波60~90 s时相对最小;在制品色差L值、|a|值、b值随着微波杀青的进行,呈先升后降的趋势,微波前90 s均较鲜叶有显著提升,而后显著下降。相关性分析表明,微波杀青时间和含水率均对L值、|a|值、b值、相对长度差等呈显著影响,总体上看以微波杀青60~90 s最有利于获得较优的外形属性。     

Root architecture of sorghum genotypes differing in root angles under different water regimes

Plant root architecture offers the potential for increasing soil water accessibility, particularly under water-limited conditions. The objectives of this study were to evaluate the root architecture in two genotypes of sorghum (Sorghum bicolor (L.) Moench) differing in root angles and to assess the influence of different deficit irrigation regimes on root architecture. The response of two sorghum genotypes, ‘Early Hegari-Sart’ (EH; steep root angle) and ‘Bk7’ (shallow root angle) to four irrigation treatments was investigated in two replicated outdoor studies using large pots. The results indicated that EH possessed steeper brace and crown root angles, fewer brace roots, greater root biomass, and root length density than Bk7 at deeper soil depths (i.e., 15–30 and 30–45 cm) compared with a shallower depth (i.e., 0–15 cm). Across the soil profile, EH had greater root length density and length of roots of small diameter (<1 mm) than Bk7. Accordingly, EH showed more rapid soil-water capture than Bk7. Different levels of irrigation input greatly affected root architecture. Severe deficit irrigation (25% of full crop transpiration throughout the season) increased the angle and number of crown roots, root biomass, and root length density compared with 75 and 100% of full crop transpiration treatments. Consequently, root system architecture can be effectively manipulated through both genotypic selection and irrigation management to ensure optimal performance under different levels of soil available water.     

粗腿羊肚菌子囊孢子萌发过程及其细胞核行为

用4μg/mL 4′,6-二脒基-2-苯基吲哚(DAPI)对细胞核染色,采用激光共聚焦显微成像技术观察粗腿羊肚菌(Morchella crassipes)子囊孢子的萌发过程。新鲜的粗腿羊肚菌子囊孢子呈椭圆状,大小13.0~15.3μm×21.5~24.0μm,成熟子囊孢子的细胞核数量为18~32个;CYM液体培养基,23℃培养6h后子囊孢子体积逐渐膨大至初始体积的1.7~2.9倍,泡囊化现象明显;6~12h开始形成芽管,泡囊逐渐消失,出芽点在椭圆形细胞的一端形成或两端先后形成,数量不等的细胞核由子囊孢子内迁至芽管中,形成多核丝状;芽管生长至20~30μm后,在出芽点与孢子连接处形成隔膜,12~24h后,随着芽管的持续生长,形成新的隔膜和菌丝细胞,菌丝细胞多核;芽管及初生菌丝直径6~8μm,约为子囊孢子直径的1/3;24h内没有观察到初生菌丝之间发生细胞融合现象。     

高温下钢管约束型钢混凝土柱的受力性能

火灾下无防火保护的结构构件温度会迅速上升,从而造成钢材和混凝土的强度明显下降。为了研究火灾下钢管约束型钢混凝土柱的受力性能,考虑火灾下钢管约束型钢混凝土柱的不均匀温度分布及温度对材料力学性能的影响,提出了火灾下受轴心荷载作用的钢管约束型钢混凝土柱承载力的计算方法。利用有限元软件ABAQUS对提出的计算方法进行了验证,结果吻合较好。进而采用该计算方法对影响高温下承载力的参数进行了分析,研究表明：随着构件截面尺寸的增加以及混凝土强度和钢材强度的提高,构件的承载力逐渐增加,而钢管壁厚的改变对承载力并无太大影响。利用有限元软件ABAQUS分析了荷载比、构件尺寸、钢管壁厚等因素对构件耐火极限的影响,发现耐火极限随着荷载比和钢管壁厚的增加而减小,随着构件尺寸的增加而增大。