浅析人工挖孔灌注桩在施工中的应用

人工挖孔灌注桩是灌注桩工程中常用的一种施工工艺.结合工程实例,详细介绍了人工挖孔灌注桩在工程施工中的应用,指出了施工过程中应当注意的质量问题,并对这些易出现的问题,提出了具体解决方法.     

限食程度对KM小鼠体重和能量代谢的影响

为阐明体重和能量代谢的生理调节对动物适应食物短缺的作用和意义,将成年KM小鼠按自由取食量的75%和50%随机限食四周,再重喂食四周.分别测定了摄食量、基础代谢率(BMR)和脂肪含量.限食75%和50%使BMR和消化道重量显著增加,体重、胴体重、脂肪含量显著降低;重喂食后,BMR和体重恢复到对照组水平,脂肪含量显著高于对照组.结果表明,动物通过能量代谢和体重调节以适应不同程度的食物资源短缺的应激环境,通过增加身体能量贮存以增强应对食物短缺的适应能力.     

压注成桩技术的应用

结合北京地铁十号线第08标段区间围护桩工程实例,探讨长螺旋成孔泵送混凝土后插钢筋笼成桩施工工艺原理、施工方法及其特点。     

Allometry of mammalian cellular oxygen consumption

In the 1930s, Max Kleiber and Samuel Brody established that the interspecies correlation between mammalian body mass and metabolic rate (αM^0.75) cannot be explained (solely) by whole body surface area (αM^0.66) to volume ratios. Metabolic considerations must also be taken into account. Decreases in the proportion of visceral organ mass to whole body mass can account for some of the whole body metabolic differences. However, superimposed upon these anatomical differences, the metabolism of tissues and cells has been demonstrated to decrease with increasing body mass. These decreases in oxygen consumption rates (with increasing body mass) in cells and tissues can be explained by a decrease in ATP turnover and mitochondrial density and an increase in mitochondrial functional efficiency (decrease in proton leak). The majority of the proton leak differences reflect differences in mitochondrial inner membrane surface area. Indeed, liver metabolism correlates directly with liver mitochondrial inner membrane surface area. Apart from being a significant contributor (~25 %) to basal metabolism, mitochondrial proton leak is a major factor determining the differences in basal metabolism between mammals of different body mass. Received 31 May 2000; received after revision 2 October 2000; accepted 14 November 2000     

配合饲料网箱养殖南方大口鲶大规格鱼种的初步试验

应用通威大口鲶配合饲料，在生产条件下进行了大口鲶大规格鱼种培育试验，验证了配合饲料诱食性及耐水性均符合大口鲶配合饲料的工艺要求；探索了转食料提高大口鲶转食率和鱼种安全过渡到利用配合饲料的途径；获得了试验期试验组近似或优于对照组的生长指标；日均增长试验组为０．１３２ｃｍ，对照组为０．１０４ｃｍ；日均增重试验组为２．２８ｇ，对照组为２．０４ｇ，经两样本均数差异显著性———ｔ检验，差异不显著（ｔ＜ｔ０．０５）；饵料系数试验组为３．６，对照组为３．７；每０．５ｋｇ鱼种饲料成本试验组为１１．７７人民币元，对照组为１３．８６人民币元，节约２．０９人民币元，降低饲料成本１７．７６％．     

威格纳分布在异步电动机故障诊断中的应用

利用 Ｗｉｇｎｅｒ分布对笼型异步机起动过程的定子电流作时频谱分析以确定其中是否有（１—２ｓ）ｆ（ｓ为滑差，ｆ为电网频率）这一断条特征量．从而诊断有无断条。结果表明：这种方法比传统的利用稳态定于电流作谱分析来诊断转子断条的方法，具有灵敏度高、信息丰富的优点，并且为双鼠笼异步电动机上笼断条的早期诊断提供了可行的途径。     

C-peptide fragments stimulate glucose utilization in diabetic rats

Studies of C-peptide cellular effects show that not only the full-length native peptide but also specific C-terminal fragments are biologically active in in vitro systems. In the present study, the effect of five C-peptide fragments and the native peptide on whole-body glucose turnover was studied in streptozotocin diabetic rats using the insulin clamp technique. Insulin was infused intravenously at 18 pmol kg^–1 min^–1 for 90 min and blood glucose concentration was clamped at 8 and 4 mM in diabetic and non-diabetic animals. A steady state was reached during the last 30 min of the study period. Rat C-peptide II and fragments comprising residues 27–31 and 28–31 were effective in augmenting glucose turnover in diabetic rats (+100% to 150%), while no significant effects were seen for segments 1–26, 11–19 and 11–15. The metabolic clearance rate for glucose during infusion of C-peptide or fragments 27–31 and 28–31 in diabetic rats was similar to that seen in non-diabetic animals. We conclude that C-terminal tetra- and pentapeptides, but not fragments from the middle segment of C-peptide, are as effective as the full-length peptide in stimulating whole-body glucose turnover in diabetic rats.Received 18 December 2003; received after revision 19 January 2004; accepted 21 January 2004     

深水网箱养殖海域水质状况评价

2003年11月至2004年6月间在青山、朱家尖、册子3个不同地点的深水网箱养殖海区采集水样,根据海洋监测规范[1]对样品的温度、pH值、溶解氧(DO)、化学需氧量(COD)、生化耗氧量(BOD5)及营养盐等化学指标进行监测分析。结果表明:网箱养殖海区各化学指标虽然比非养殖海区偏高,但是差别较小,说明养殖未给周围水环境带来严重污染。养殖海区营养盐超标现象严重,属四类海水标准,且富营养化状况严重,但这在浙江沿岸尚属正常。     

新型万向联轴器同步条件的研究

本文对以钢球来传递运动的这类万向联轴器的同步条件进行了研究,导出当输入输出两轴线相交时的同步条件的表达式,论证了两轴在空间交错时不存在同步条件,并以球笼联轴器和三叉式联轴器为实例进行说明。本项研究可为今后研制新型同步万向联轴器提供理论根据。     

方形网箱减流效果的试验与应用

依据深水网箱实际尺寸和渔具水槽试验方法,设计方形结构网箱进行水槽减流实验。应用三维流速计测量网箱尾部各点在不同水流实验条件下的流速,分析相关数据,探讨网箱尾部的流速分布,评价浮式网箱的减流效果。流速测试范围在网箱后50～125 cm的2个水层,减流效果明显,结果显示:(1)网箱尾部的减流区域集中在网袋与来流垂直的投影面中部,而网箱两侧的流速略有增加;(2)当流速由32.23 cm/s增大到67.79 cm/s时,减流20%～45%。在网箱养殖海域设计应用网箱型的组合浮式防波堤,最大减流55%以上,表明能够满足深水网箱养殖的减流需要。