有摩擦的高速气体管流

本文以多变热力过程为基础建立了有摩擦管路的计算公式,并对计算方法和有关问题作了分析说明.     

Influence of Low Light Irradiance on Grain Filling in Rice (Oryza saliva L.) cultivars

Time course of grain filling pattern in two rice (Oryza sativa L.) cultivars, grown under normal and low light intensities, was studied. The number of spikelets, partially filled grains and high density grains were monitored at a 5 day interval during grain filling period from uniform panicles tagged at anthesis. The low light tolerant cultivar Swarnaprabha had more high density grains and less partially filled grains throughout the grain filling period and at harvest compared to cultivar Ratna under both normal and low light intensities. Further, the opening of spikelets in two flushes in Swarnaprabha seemed to result in a more efficient resource allocation and hence better yield as compared to Ratna, in which the opening of spikelets was in a single flush on day 10.     

Influence of the Indoleacetic Acid-Lysine Synthetase Gene (iaaL) of Pseudomonas syringae subsp. savastanoi on Yield Attributes of Potatoes

The iaaL gene of Pseudomonas syringae subsp. savastanoi encodes an indoleacetic acid-lysine synthetase which conjugates free indoleacetic acid (IAA) with lysine. lAA-lys is biologically less active than free IAA. The iaaL coding region was expressed under the control of the cauliflower mosaic virus 35S promoter and transgenic potato plants were produced (Spena et al. 1991). 35S iaaL potato plants are characterized by increased internodal length and epinastic bending of older leaves. In three greenhouse experiments with plants grown in pots of different size and in two growth chamber experiments tuber number increased in iaaL transgenic plants compared to untransformed and vector-transformed controls of the same genotype. The increase in tuber numbers observed under controlled conditions was reflected in tuber yield which increased in the pot grown transgenics.     

科技期刊页码编排问题分析

参照国家现行的《科学技术期刊编辑格式》（GB/T 3179）,对我国公开出版的科技期刊页码编排规范情况进行了调查。结果发现少数期刊页码编排存在跳码、重码、漏码、错码、单双页码位置颠倒、加码和暗码太多等问题。建议载文短的科技期刊篇首页尽量不要采用暗码编排,以利发挥页码的功能、方便读者查阅和复制。     

金顶侧耳不亲和性因子多样性的研究

按照传统不亲和性因子测定方法,通过真、假锁状联合的有无,鉴定6个金顶侧耳菌株的不亲和性因子,结果表明,金顶侧耳菌株具有不亲和性因子多样性的特点,6株金顸侧耳菌株除蕈谷2号榆黄蘑与张榆具有相同的A1A3B1B3不亲和性因子外,榆黄P103、RYH1、RYH2、榆黄菇分别具有A1A2B1B2、A4A5B4B5、A4A6B4...     

用鳞片估计马来穿山甲个体数量

我国每年都能查扣到多起非法走私大量马来穿山甲鳞片进入境内的案件,由于不知如何根据鳞片来估计个体数量,而给森林公安机关立案、量刑与处罚带来极大不便。通过统计9头马来穿山甲鳞片的数目（Sm）、鲜重（Sfw）、干重（Sdw）,分别获得了以Sm、Sfw、Sdw为参数来估计马来穿山甲个体数量（N）的3个方程,它们是①Sm/929.8≤N≤Sm/681.8;②Sfw/835.4≤N≤Sfw/389.8;③Sdw/774.3≤N≤Sdw/367.9。执法部门在办理此类走私案件中能通过这些方程方便快捷地估算出走私物品的个体数量,能为同类案件的立案、量刑和处罚提供依据。     

次氯酸钠处理对E.tenella球虫卵囊的影响

１４日龄爱维茵鸡接种Ｅ．ｔｅｎｅｌａ广东株７．５ｄ后,扑杀,其盲肠粘膜刮取物及内容物以１：５次氯酸钠（含活性氯不低于７．５％）处理２０ｍｉｎ后,离心清洗,加２．５％的重铬酸钾,置敞开的大平皿中,２８℃环境下孢子化。同时设未经次氯酸钠处理的对照组。４８ｈ与７２ｈ后分别取样检查其孢子化率。结果发现,次氯酸钠处理组孢子化率与未经次氯酸钠处理的对照组无显著差异。所得孢子化卵囊接种鸡的试验结果表明,低剂量下,未处理组显示出较强的致病力,不过平均卵囊数相差不大;较高剂量下,处理组病变略轻,而平均卵囊数明显高于未处理对照组。     

利用微滴数字PCR技术分析转基因大豆‘GE-J12’中外源基因的拷贝数

为鉴定抗除草剂转基因大豆新品种‘GE-J12’的外源基因插入拷贝数,以该转化体的外源插入目的基因G2-EPSPS和GAT的序列、3′转化体特异性序列为靶序列,设计PCR扩增引物和TaqMan探针,并对引物探针特异性进行鉴定,同时以大豆内标基因Lectin为参照,建立微滴数字PCR拷贝数检测体系。特异性试验结果显示,只有以抗除草剂转基因大豆‘GE-J12’基因组DNA为模板才有扩增信号。以单株转基因大豆‘GE-J12’基因组DNA为模板,进行外源目的基因G2-EPSPS和GAT、3′转化体特异性序列的微滴数字PCR检测,转基因大豆‘GE-J12’的外源目的基因G2-EPSPS和GAT在基因组上的插入拷贝数均值分别为0.99和1.01。同时3′转化体特异性序列的拷贝数均值为1.00,验证单株转基因大豆‘GE-J12’为纯合子,因此鉴定该单株转基因大豆‘GE-J12’的外源基因在大豆基因组上为单拷贝插入,同时与Southern blot方法进行比较,结果一致。     

两个黄芪亚种染色体数目与核型分析

前人研究认为膜荚黄芪（Astragalus membranaceus（Fisch.）Bge.）与蒙古黄芪（Astragalus membranaceus（Fisch.）Bge.var.mongholicus （Bge.）Hsiao）染色体数目为2n=16。本试验采用根尖染色体常规制片方法,观察了膜荚黄芪与蒙古黄芪种子根尖有丝分裂相。结果显示：膜荚黄芪与蒙古黄芪染色体数目为2n=18,这2种植物各有4条小染色体。膜荚黄芪染色体核型公式为K（2n）=2x=18=4sm+14m,核型类型为2B型。蒙古黄芪染色体核型公式为K（2n）=2x=18=6sm+12m,核型类型为2C型。     

复合益生菌菌液对奶牛产奶量和肠道菌群的影响

为了研究复合益生菌菌液对奶牛产奶量、乳品质量、牛群健康和肠道菌群的影响,选择20头条件相近的健康奶牛随机分为试验组和对照组,采用菌液与饲料混合的方法饲喂牛群,考察其对奶牛产奶量,肠道菌群乳品质量和牛群健康的影响。结果表明,食用复合益生菌液的每头牛比对照组平均每天可以多产2.9kg牛奶,提高产奶量14.8%,差异极显著(P0.01),经济效益显著;复合益生菌菌液可以促进肠道菌群调整,使有益菌-主要是乳酸菌成为优势菌群,并可以抑制霉菌和降解霉菌毒素,降低牛乳中体细胞数,预防隐性乳腺(房)炎。