检测条件对人造板吸水厚度膨胀率测定结果的影响

研究了恒温恒湿处理和浸渍温度对人造板吸水厚度膨胀率检测结果的影响.结果表明:中密度纤维板和刨花板的测定值随着浸渍温度的升高而增大,两者存在着一定的线性关系,而胶合板则受水温影响很小;在浸渍前试件进行恒温恒湿处理与否会影响测试结果.对于刨花板和薄型中密度纤维板,进行恒温恒湿处理是必要的.     

The occurrence of summer mastitis in Jutland (Denmark) in relation to meteorological factors

Data for incidence of summer mastitis in 14 veterinary practices in Jutland (Denmark) were related to meteorological factors using statistical methods. A correlation and regression analysis showed that summer mastitis occurred earlier in years with high temperature and precipitation in early summer. The annual number of cases markedly increased over the years 1953 to 1980. This increase was described by applying a linear increase with with year to a logarithmic transformation of the annual incidence.Analysis of 10-day incidences from the veterinary practices and daily incidence from a test site at St. Vildmose (Jutland) showed that incidence of summer mastitis could be related to temperature and wind velocity within the previous 10 days. High temperature and low wind velocity in this period increase the incidence. This indicates that the incubation period of summer mastitis is at maximum about 10 days. The activity of the fly (Hydrotaea irritans Fall), which acts as mechanical vector for the bacteria is influenced by temperature and wind velocity. This may explain the variation in incidence of summer mastitis during the season and from year to year.     

滚珠丝杠的温升及热变形对策

对滚珠丝杠的温升及热变形的对策进行了探讨，提出解决温升和热变形的方法，为滚珠丝杠的设计、安装、使用和维修提供参考。     

Influence of Constant Temperature on Reproductive Parameters of Holotrichia oblita (Coleoptera: Scarabaeidae)

Holotrichia oblita Faldermann (Coleoptera: Scarabaeidae) is a major pest both in field crops and forests because the larvae could eat the roots of most crops in the field, and the adults damage the leaves of trees and field crops. In this study, we focused on the effects of temperature on H. oblita reproductive parameters. The results indicated H. oblita female adults at 25°C could lay more eggs (84.0 eggs per female) and have the shortest preoviposition period (19.1 d), the greatest oviposition rate (2.8 eggs per female per 3 d), and largest percentage of life span spent in oviposition (59.5%). The longevity and the time to 50% egg laying decreased with increasing temperature, and female longevity was always longer than male longevity. The preoviposition and postoviposition period decreased with increasing temperature from 15 to 25°C and then increased when the temperature increased from 25 to 30°C. These results show that 25°C is the optimal temperature for reproduction of H. oblita.     

温升与横向力作用下圆板跳跃的有限元数值模拟

采用ANSYS程序计算了热力联合作用下圆板的轴对称跳跃规律,得到了用板中心挠度表示的跳跃过程和跳跃后临界挠度温升和临界横载温升关系。结果表明,临界挠度与温升或临界横载与温升都呈非线性递增关系。     

“七五”国家科技攻关项目 蔬菜新品种选育研究——Ⅴ.白菜专题育成的新品种(系)简介

本文介绍了1986～1990年白菜专题11个单位育成的22个白菜新品种(系)。其抗病性、品质、产量均优于原有品种。全部通过了农业部主持的专家组验收。     

烯效唑浸种对黄瓜的壮苗效应

研究不同浓度烯效唑浸种对黄瓜幼苗生长发育的影响。结果表明,烯效唑可抑制黄瓜幼苗徒长,使株高降低,比叶重增加,根冠比和壮苗指数增大,叶绿素含量增加,根系活性增强,在形态上和生理上表现出显著的壮苗效应;烯效唑对黄瓜有极显著的增产作用,以20 mg·kg-1处理最佳,促进增产的主要原因是提高了单株结瓜数。     

反相高效液相色谱法测定枸杞中有机酸的含量

[目的]建立反相高效液相色谱法测定有机酸含量的方法。[方法]采用ultimate-C18色谱柱,以磷酸盐缓冲溶液（pH=2.0）为流动相,流速0.5ml/min,检测波长210nm,建立草酸、酒石酸等7种有机酸的高效液相色谱分析方法,并对枸杞中几种有机酸进行了分析。[结果]在22min内实现了7种有机酸的基线分离,检测限为0.001～0.039mg/L。[结论]该方法具有分析速度快,线性范围宽,重现性好、灵敏度高的优点,适用于枸杞中有机酸含量的测定分析。     

基于猪粪水热炭化的生物炭性能及残液成分分析

为系统研究不同炭化温度条件下猪粪水热炭化规律,本研究以猪粪和发酵猪粪为供试材料,采用水热炭化工艺在系列温度条件下（180、240℃和300℃）制备生物炭,对其元素含量、热稳定性、孔隙结构、表面官能团等理化性质进行表征,并对水热炭化残液进行成分分析。结果表明,猪粪生物炭和发酵猪粪生物炭均具有发达的孔隙结构、丰富的表面官能团等优良特性,其H/C原子比和热失重率均随炭化温度升高而减小,表明热化学稳定性随炭化温度升高而增强。水热炭化残液的成分主要包括有机酸、醇、酯、醛、吡嗪、苯酚等物质,较高炭化温度条件下残液中化合物种类更丰富。与猪粪相比,发酵猪粪水热炭化残液的成分仍然以酚、烯、酮类物质为主,但呋喃、吡啶、吡嗪类毒性化合物消失。研究表明,发酵猪粪在300℃条件下水热炭化的残液用作液态肥料的安全性更高,在资源化利用方面更具优势。     

两种温度条件下黄颡鱼胚胎发育观察

研究了人工授精后黄颡鱼(Peudobagrus fulvidraco)卵胚胎的发育情况，比较在两种温度条件下胚胎发育时序的变化。结果表明：水温对胚胎发育影响较大，21．0～25．5℃时，胚胎发育过程为72h 50min；19．0～22．0℃时，需要77h 20min。