雪松营养器官中树脂道的分布与发育

为弄清雪松营养器官中树脂道的发生、发育过程及分布特点,采用石蜡切片的方法对雪松营养器官中树脂道的发生及分布进行研究.结果表明:雪松针叶和茎初生树脂道的发生与发育过程基本相似,都属于裂生型,发育过程分为4个阶段:原始细胞阶段、胞间隙形成阶段、腔道扩大阶段和树脂道成熟阶段.雪松针叶中有2个边生的树脂道,一年生茎的树脂道分布在皮层,二年生茎的次生韧皮部中有6～10个树脂道,雪松根中未观察到树脂道结构.     

Gonadal development in early life stages of <Emphasis Type="Italic">Spratelloides gracilis</Emphasis>

ABSTRACT:   The gonad of Spratelloides gracilis was not sexually differentiated in the yolk-sac, preflexion, flexion and postflexion stages. Sexual differentiation and development of the ovary and testis started in the transition stage from larva to juvenile. In juveniles at the fin ray completion stage, the ovary and testis could be distinguished because the ovary contained germ cells initiating meiosis and the testis had blood vessels and a high density of somatic cells. The ovary further developed in larger juveniles to have oocytes of perinucleolus stage together with those of the chromatin nucleolus stage, and oogonium. However, in the testis of larger juveniles, primary spermatogonium began proliferation by meiosis. Sexual differentiation may be regarded as one of morphological and functional changes accompanying metamorphosis in S. gracilis . Some fish larger than the mature size of 60 mm standard length had advanced germ cells and functional gonads, others did not have functional gonads. The distal end of the immature gonads did not connect with a genital duct near the anus. These observations indicate that S. gracilis has large variability in size-at-maturity. The variability in size-at-maturity in S. gracilis , together with large variability in age-at-maturity, may constitute an ecological basis for an extended spawning season in S. gracilis .     

Post mortem computed tomography as a complementary tool for diagnosing cholangiohepatitis in a giant panda (Ailuropoda melanoleuca)

A geriatric female giant panda developed grave signs of illness and was diagnosed with suspected hepatobiliary tract obstruction or other severe hepatic disease such as advanced cholangiohepatitis. The giant panda was euthanized and post mortem computed tomography was performed prior to necropsy. Common bile duct obstruction at the major duodenal papilla by a mineral attenuating calculus causing dilatation of common bile and gallbladder with concurrent multiple areas of liver abscess were detected by postmortem computed tomography. These were confirmed with gross necropsy. This is the first case report of common bile duct obstruction by mineral calculus with concurrent severe cholangiohepatitis in a giant panda.     

一种新型天敌昆虫蠋蝽在林业上的应用

目的蠋蝽是一种重要的捕食性天敌昆虫,观察其生殖器及胸足感受器类型及其形态特征,有助于探究其寄主选择等行为的机理。方法采用扫描电镜对蠋蝽生殖器及胸足感受器类型及其形态进行观察。结果蠋蝽雄虫交配器和雌虫产卵器上的感受器均有4种,分别为毛形感受器、刺形感受器、腔锥形感受器和锥形感受器,但雌虫产卵器上的刺形感受器和毛形感受器长度长于雄虫交配器;雌虫和雄虫胸足上的感受器有5种,分别为毛形感受器、刺形感受器、腔锥形感受器、锥形感受器以及Böhm氏鬃毛感受器,但雌雄虫胸足上的感受器大小存在一定差异：雌虫中后足上的刺形感受器长度长于雄虫,雌虫后足上的毛形感受器(Ⅰ型和Ⅱ型)长度长于雄虫,雄虫前足上的Böhm氏鬃毛感受器长度长于雌虫。结论蠋蝽生殖器和胸足上都存在多种类型的感受器,其形态和种类差异不大,仅部分感受器大小存在差异。     

风送式喷雾机风筒结构对飘移性能的影响

为改善风送式喷雾机的飘移性能,为原有喷雾机的出风口设计安装一个锥形导风筒和一个同轴柱形导风筒.试验结果表明:锥形导风筒可以约束气流的运动轨迹,提高气流在水平方向的速度,有效约束雾体、减小能量损失;同轴柱形导风筒可以使风筒出口的气流速度成梯度分布,速度外高内低的气流可约束雾滴的运动轨迹,减小雾滴飘移,使沉积率提高30.6%.     

温室大跨度薄膜风筒送风特性模拟及试验研究

现代大型温室普遍使用送风末端为长距离柔性薄膜风筒的空气处理机组（air handling unit,AHU）作为温度控制功能单元来完成大空间内的热量输送。为探究此类风筒AHU的性能,该研究采用理论分析和数值模拟方法研究其送风特性,并通过试验验证计算模型的正确性。结果显示,薄膜风筒内不同截面的静压在开孔部位急剧减低至0,同时气流速度明显增加,但是影响范围不大,对风筒内的压力场和流场影响较小。在风筒同一截面上不同开孔位置流出的气体速度和速度分布基本一致,以风筒入口端风速2.45 m/s为例,在风筒60.06 m处风筒壁开孔处气流最大速度为5.64 m/s,位于开孔中心处,并垂直与开孔平面向外流动,速度分布为中心流速最高,越靠近孔边缘流速越低。对风筒沿长度方向通过筒壁各开孔流出的风量进行计算发现,在不同风筒入口风速条件下送风量基本保持恒定,均匀性系数均大于0.92,说明此类风筒能够沿长度方向均匀地配送气流,可将热量或者冷量在温室大空间内进行均匀投送,从而为现代大型温室内空间内维持温度场均匀提供保障。     

Estimating the amount of collagen and elastic fibres in bovine teats

The amount of collagen and elastic fibres near the Fürstenberg's rosette in histological sections of bovine teats was estimated using the ImageJ image processing software. This method holds promise for comparing tissue types within and between sections but it was not a reliable way to quantify the absolute amount of tissue types in a sample. The amount of elastic fibres and collagen was similar in cow teats with a history or acute case of mastitis infection and in non-infected cows, but this could not be statistically tested due to limitations in the study material.     

A stereological analysis on the calculation of the volume values of thoracic segments in ducks

Stereology is a method for examining two-dimensional objects as three-dimensional objects. The aim of this study was to offer volume values for thoracic segments in ducks by means of stereological methods. This study examined the data obtained from stereological analysis of the total volume and grey and white matter volume values of the thoracic segment, a part of the adult duck spinal cord with a weight of 3–4 kg. In the study, study samples consisted of 10 adult ducks (Anas) used without gender discrimination. To perfuse all of the animals, 10% formaldehyde was utilised. The perfused animals were kept in 10% formaldehyde for one week. The spinal cord was uncovered following the removal of arcus vertebrae parts of thoracic vertebrae in the thoracic part of dissected ducks. Tissue samples of thoracic segments were taken; 5-µm-thick cross sections from these tissue samples were taken via microtome. Attention was paid to obtaining samples at the ratio of 1/250 by taking 12 cross sections from each segment. The cross sections were subjected to haematoxylin-eosin staining. Photographs of all cross sections were taken using a microscope. The volume values of all tissue and grey and white matter structures in each thoracic segment of the spinal cord were calculated. The total volume, grey and white matter volume densities in thoracic segments of ducks, as well as the data obtained as a result of proportioning volume values of one another are represented in the conclusion section of this study.     

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。 