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191.
通过统计大庆外围特低丰度薄层油藏14个区块、90口水平井、245口直井的地质、油藏工程及生产历史资料数据,利用多因素综合分类分析法,系统分析水平井开发效果与各种地质及工程因素之间的关系。研究表明,地质影响因素主要为砂体类型、注采连通关系及油水同层发育程度,开发调整措施的适应性是影响水平井生产效果的主要因素。 相似文献
192.
用弹簧模仿人的腰椎,对动力学简化模型进行了线性化处理,建立状态空间方程对其进行控制,并从数学角度验证了模型的正确性. 相似文献
193.
194.
为解决柔性装配系统的调度问题,采用分层时延Petri网模型与蚁群优化算法相结合,将柔性装配系统分解成诸多个装配体,每个装配体再分解成多个柔性装配单元,对装配单元分别建模并用蚁群算法对装配方案遍历优化,最后确定装配系统的时延Petri网模型.该方法融合了Petri网和蚁群算法各自的优点,较好地解决了柔性装配系统中的装配建模和装配任务的分配优化问题.实验证明该研究可行有效. 相似文献
195.
F. Campos J. Atkinson J. T. Arnason B. J. R. Philogène P. Morand N. H. Werstiuk G. Timmins 《Journal of chemical ecology》1989,15(7):1989-2001
2,4-Dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), the major hydroxamic acid present in corn, and its tritiated derivative, were prepared synthetically for use in the determination of the toxicokinetics of this insect deterrent in the European corn borer (ECB),Ostrinia nubilalis. In growth studies with DIMBOA (0, 0.05, 0.2, and 0.5 mg/g diet), the mean time to pupation and adult emergence were significantly lengthened by an increase in concentration. Pupal and adult weights, for both female and male, decreased with an increase in concentration. Increased larval and pupal mortality occurred at the highest concentration of DIMBOA. DIMBOA, at concentrations of 0.2 and 0.5 mg/g diet, resulted in a decrease in the number of egg masses produced per female, and at 0.5 mg/g diet, in a decrease in the number of eggs per egg mass. Larvae fed from the neonate stage on a diet containing 0.2 mg [3H]- + [1H]DIMBOA/g diet showed an increase in the content of label from fourth to fifth instar, but levels declined at pupation and emergence. A large amount of the labeled compounds was excreted by the insect in the pupal case. In dose-related studies, both uptake and excretion increased with an increase in concentration of DIMBOA (0.05, 0.2, 0.4 mg/g diet), while a body burden (concentration in the tissues/concentration in the frass) of approximately 0.25 was maintained for all concentrations. At the highest dose of DIMBOA (0.4 mg/g), the ECB increased consumption, possibly to compensate for the toxic effects of the compound. In topical application studies, elimination of the labeled compound in the frass was rapid, reaching 65% by 4 hr and 88% by 48 hr. Accumulation of label in tissues other than hemolymph was low. The results show that the ECB does possess adaptive mechanisms to deal with the effects of this host-derived compound. 相似文献
196.
溶胶-凝胶法CaO-P2O5-SiO2系生物玻璃的制备及机理探讨 总被引:7,自引:0,他引:7
以正硅酸乙酯[Si(OC2H5)4]、四水硝酸钙[Ca(NO3)2*4H2O]等作为前驱体,采用溶胶-凝胶工艺制备CaO-P2O5-SiO2系生物活性玻璃,把制备的样品放在模拟体液中浸泡一段时间后取出,以X-射线衍射、红外光谱等手段对其作物相分析,确定在玻璃的表面有羟基磷灰石相生成,同时对其形成机理做了进一步探讨. 相似文献
197.
During courtship, premolt female lobsters,Homarus americanus, choose a male and initiate a pair bond by repeated approaches to his shelter. The male allows such a female to share his shelter for about one week. This knowledge formed the basis to search for quantitative evidence for lobster sex pheromone(s) used in courtship: male cues to allow premolt females to identify a preferred male, and female cues to allow males to identify a premolt mature female. In each of four 1500-liter naturalistic aquaria, the behavioral responses of one female and two male lobsters to male and female lobster urine (0.5 ml) and body odor (20 ml) stimuli were observed. These stimuli were injected once or twice per day into a continuously flowing delivery tube attached to lobster shelters. Habituation to stimulus introduction—a serious problem in earlier experiments—was apparently avoided in the more natural social and physical environment we employed in these experiments. We demonstrated that male and female molt body odors contain different chemical substances: females responded to male molt body odor and males responded to female molt body odor but not vice versa. In general, male and female intermolt urine caused strong responses; however, females responded only weakly to male urine. This suggests that male and female urine are chemically different. Female urine and molt body odor caused a typically male high-on-legs response. These results show that molt body odors and intermolt urine contain sex-specific substances, which may be used in lobster courtship as well as other social interactions. 相似文献
198.
针对小型柔性生产线中PLC之间需要进行实时数据通信这一问题,设计基于S7-200PLC的PPI网络通信系统.介绍PPI网络的特点和设计步骤,重点阐述通信读写数据的规划、通信子程的生成及调用、主站和从站的通信子程序设计等关键技术. 相似文献
199.
Research on hydropeaking in Austria started in the 1990s and the implementation of the WFD stipulated large research projects since the year 2009. The first research projects supported the process understanding and in a second investigation step, measures were evaluated. The mountains in the region of Tyrol create large heads and thus support the production of flexible energy. In this region, TIWAG is operating 9 large (>10 MW) and 27 small (<10 MW) hydropower plants, with an installed capacity of about 1,550 MW and a mean annual production of 3,000 GWh. As the governmental energy strategy foresees an extension of the hydropower production in Austria, suitable options were selected in 2004 by TIWAG and the water management framework plan for Western Tyrol was developed. This strategic planning instrument proposes five large power plants, with a generation of 1,800 GWh/year of renewable energy, which enables to reach the WFD targets, because the concept includes hydropeaking mitigation by combining buffer reservoirs (impoundments), diversion hydropower plants, and retention basins. We present our promising concept of hydropeaking mitigation and exemplify this based on the GKI, a hydropeaking diversion hydropower plants (HPP) at the Swiss/Austrian border as well as the Silz hydropeaking retention basin, with a volume of about 300,000 m3. As the presented case studies are the largest measures for hydropeaking mitigation being currently implemented in Central Europe, they have pilot-character. Thus, ongoing research and monitoring programs are expected to improve the knowledge about hydropeaking mitigation. 相似文献
200.
堰塞体溃决洪水洪峰流量及洪水时程曲线特征的预测是堰塞湖应急抢险及下游风险控制方案制订的重要依据。堰塞体溃决的离心模型试验,在研究堰塞体溃决机理、溃决过程及溃决洪水的历时曲线特征方面独具优势,但离心模型试验供水系统的设计,涉及到从外部静止状态到高速旋转状态的模型中连续供水,同时还要保证堰塞体溃决过程中上游水位为设定的常水头,是堰塞体溃决离心模型试验中的关键性的一大难题。本文围绕以上难题,设计了一种环形水箱以解决从静态到动态模型的连续供水问题,通过理论分析,确定了环形水箱中可提前注入的最大水量。另外在试验箱设置了竖井式溢流口,可以排出高出设定常水头的水体,保证了上游水位的稳定。通过以上设计有效地解决了供水系统中的关键难题,并在后续堰塞体溃决离心模型试验中得到了验证。 相似文献