超重车辆过桥措施的探讨

本文论述了桥梁实际承载能力方法确定及超重车辆过桥的一般要求;同时阐述了桥梁加固措施.     

鹌鹑原始生殖细胞的分离及冷冻

以酶分解法消化孵化了5.5d的鹌鹑性腺得到鹌鹑PGCs,比较了3种不同酶消化时间所得的细胞数量;采用2种不同的冷冻方法冻存鹌鹑PGCs。结果表明：消化15min对于鹌鹑PGCs的分离最佳,而2种冷冻程序所得的活细胞数量差异不显著。     

考虑地基刚度的底部两层框架砖房自振周期的计算

提出了一个考虑地基刚度并结合下柔上刚的结构特征，把一栋建筑物作为一个整体建立相应的力学模型，最后得到一个计算此类结构自振周期的实用计算方法。     

特效营养剂“新丰2号”在烟草上的应用

烟草在生产管理上存在着众多矛盾,如产量与施肥、叶片与成熟度、叶面积与烟叶品质、绿色环保与有害物质残留、投资与成本等。但在烟草生长前期喷洒2~3次新丰2号,这些矛盾就会迎刃而解,株高增8.2%~25.6%,茎围增粗37.5%~90.6%,叶片多4.0~8.3片,节距缩短5.1%~9.7%,叶面积增加39.9%~76.7%,产量提高10.9%~63.8%,上等烟比值提高到35.2%~72.6%,经济效益增加32.6%~131.0%。     

3H—萱草根素在小鼠体内吸收分布,排泄和代谢的初步观察

本文应用放射性同位素示综技术,初步观察了~3H-萱草根素在小鼠体内吸收分布、排泄和代谢的全过程。~3H-萱草根素口服后0.5小时,小鼠血液中放射性即达到高峰,并以低浓度维持96小时以上;其随血液循环分布于各组织器官,以胃肠组织含量最高,其次是肝脏和脾脏。萱草根素有蓄积性;一次给药和以同等剂量分次(每天一次,三天)投药后的相同时间,各组织中~3H-萱草根素的含量差异不显著。主要排泄途径是粪便,其次是尿液。经有机溶剂处理后的尿液分为水、脂二相,其放射性测量和薄板层析放射自显影结果均表明:~3H-萱草根素在体内经过代谢后结构发生了变化,从尿液中排出的不是萱草根素原形,而是其代谢产物。     

准噶尔南缘扇缘带种植业结构分析

通过对准噶尔南缘扇缘带种植业生产的分析及试验研究，提出了适合本地带农田的经粮结构、草经粮结构、林经草结构和专业化生产４种种植业结构类型。根据经济效益、生态效益和社会效益综合评定，认为采用草粮或林经草种植业结构类型，同时贯彻以牧为主、农牧结合的方针是本地带开发利用的最佳途径     

Pattern of Kirtland's warbler occurrence in relation to the landscape structure of its summer habitat in northern Lower Michigan

Studies of the endangered Kirtland's warbler in relation to landscape ecosystems were conducted from 1986–1988 on a large wildfire-burn surrounding Mack Lake in southeastern Oscoda County, Michigan. A landscape ecosystem approach was used to distinguish low- and high-elevation segments of the landscape, as well as 11 local ecosystem types. The ecosystems were distinguished by physiography, microclimate, soil, and vegetation. The early occurrence of the warblers was strongly related to landscape structure, i.e., to the broad low- and high-elevation areas and the local ecosystem types within them. Territories of male warblers were observed in 5 of the 11 ecosystems. The five ecosystem types where warblers were observed were characterized by (1) a physiography of level or rolling terrain; (2) soil series of Grayling, Graycalm, Montcalm, or Rubicon; (3) uplands with relatively warm temperature during the breeding season; (4) vegetation dominated by low sweet blueberry, bearberry, wintergreen, northern pin oak, blue stem grasses, and hair cap moss; and (5) canopy of relatively tall, dense, and patchy jack pine and oak. Landscape structure appears to be an important factor affecting the occurrence of the warbler in its summer habitat in northern Lower Michigan.     

谷氨酰胺的抗疲劳生化机制研究

用两批各 48只小鼠分 4组 (n =12 )每天分别灌喂生理盐水和 3 4mmol·kg-1的谷氨酰胺、谷氨酸和天冬酰胺 ,连续 10d。结果显示 ,三者都可提高小鼠血清、肝和骨骼肌中的肌酸磷酸激酶活性 ,降低乳酸脱氢酶活性 ,并显著增加肝、骨骼肌糖原积累。其中有相同碳架结构的谷氨酰胺、谷氨酸能极显著提高小鼠的游泳耐力 ,但与谷氨酰胺有相等酰胺氮的天冬酰胺作用不强。结果提示 ,谷氨酰胺提高机体抗疲劳作用与其碳架结构有关     

促食物质和阻食物质相互作用对家蚕摄食性的影响

以 4龄起蚕取食饲料一定时间后的排粪量为指标 ,探讨了促食性物质和阻食性物质对家蚕摄食性的影响。结果表明 ,将桑叶粉、蔗糖、肌醇等促食物质同时添加到饲料中 ,对家蚕的取食有协同促进作用。脱脂大豆粉、柠檬酸等摄食抑制物质的阻食作用也具有累加性。而将促食物质和阻食物质混合添加时 ,二者表现为相互抑制效应。添加促食剂是减弱或消除阻食性物质的摄食抑制作用的有效途径。