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排序方式: 共有251条查询结果,搜索用时 31 毫秒
91.
东海油田春晓3井凝析气全组分模拟 总被引:1,自引:1,他引:0
凝析气相态实验及全组分模拟分析是合理开采凝析气田和提高凝析油采收率的关键。凝析气相态实验分析能直接得出流体的物性参数 ,但并非能测定所有成分的参数。对相态实验不能测定的成分 ,可根据已测参数确定合适的流体相态模型 ,模拟计算出由实验方法不能测定的参数。全组分模拟能精确地模拟不同凝析气藏开采过程中油、气两相组分的瞬间变化、井流物中重组分含量以及一定分离条件下采集到的凝析油量。 相似文献
92.
DA Halon A Merdler MY Flugelman G Shifroni N Khader A Shiran J Shahla BS Lewis 《Canadian Metallurgical Quarterly》1998,82(5):547-553
To characterize KC 12291 (1-(5-phenyl-1,2, 4-thiadiazol-3-yl-oxypropyl)-3-[N-methyl-N-[2-(3,4-dimethoxy phenyl) ethyl] amino] propane hydrochloride), a newly synthezised inhibitor of voltage-gated Na+ channels, the effects of the agent on Na+ current and ischemia-induced Na+ overload were investigated in isolated cardiomyocytes, atria and saline-perfused hearts. As measured by the patch clamp technique, KC 12291 (1 microM) significantly reduced peak Na+ current after activation of voltage-gated Na+ channels in rat cardiomyocytes. Partial depolarization enhanced the inhibitory effects during steady state conditions of the channel. In isolated guinea pig atria, 1 microM KC 12291 had no effect on contractility under basal conditions but effectively delayed the onset and reduced the extent of anoxic contracture. The concentration-response curve was clearly shifted to the left when atria were partially depolarized by increased extracellular K+. As measured by 23Na NMR spectroscopy in isolated perfused guinea pig hearts, intracellular Na+ rose more than four-fold in a linear fashion during 60 min of low-flow ischemia. KC 12291 (1 microM) prevented Na+ overload within the initial 12 min of ischemia; thereafter the slope of Na+ accumulation was identical to controls. Electrical excitability of hearts, evaluated by intracardial ECG, completely ceased within 15 min after the onset of ischemia. KC 12291 (1 microM) accelerated this process by more than 6 min. The data provide first evidence that KC 12291 reduces Na+ influx through voltage-gated Na+ channels during ischemia and thus delays Na+ overload by enhancing the inexcitability of the heart. 相似文献
93.
We consider the problem of setting order quantities for purchased components subject to uncertainty in the delivery amounts. Assuming the periodic production volumes (demands)to be known and constant, we model this as a random yield problem with the objective of minimizing average inventory cost subject to a service level constraint over the infinite horizon. We first demonstrate that under conditions of random yield, conventional definitions of service can be inappropriate. Then we refine the definition of service for random yield cases and use this to formulate an optimization model. Exact solution of this model proves to be computationally impractical and, as we show, the common heuristic of inflating demands by a constant proportion is not robustly accurate. Therefore, we develop a new heuristic, which we term the linear inflation policy, that specifies a linear function for the inflation factors. Numerical tests indicate that this heuristic can substantially outperform the traditional constant inflation policy and works well relative to a lower bound on the optimal solution on a range of examples. 相似文献
94.
The purpose of the paper is to develop a solution for application of PV (photovoltaic) generators in MV (medium voltage) distribution system without unacceptable voltage changes due to drops of PV power output. The proposed solution includes operation of PV with predetermined leading power factor and addition of a capacitor bank in parallel to PV plant in order to compensate the reactive power absorbed by the PV inverters. The analytical expression of required power factor angle is derived. Adding a capacitor bank in parallel to PV power plant may pose a problem because of space limitations. The dimensions and cost of small MV capacitor banks depend significantly on the capacitor bank protection against internal faults. Application of the developed negative-sequence current difference method for the unbalance protection of the capacitor banks enables to achieve a compact and cost-reduced design of the banks connected in parallel to PV power plants. A real-world example of operation of the PV plant in parallel to the capacitor bank with the novel protection scheme is described. 相似文献
95.
长兴·秀江南会所是王骏阳的新作。本文不仅试图在中外建筑的广阔语境中对这一作品进行分析,而且也着重阐述了它在现象学层面所呈现出来的空间品质。 相似文献
96.
Shiran Su Thomas J. Esparza Duong Nguyen Simone Mastrogiacomo Joong H. Kim David L. Brody 《International journal of molecular sciences》2021,22(16)
Iron oxide nanoparticles and single domain antibodies from camelids (VHHs) have been increasingly recognized for their potential uses for medical diagnosis and treatment. However, there have been relatively few detailed characterizations of their pharmacokinetics (PK). The aim of this study was to develop imaging methods and pharmacokinetic models to aid the future development of a novel family of brain MRI molecular contrast agents. An efficient near-infrared (NIR) imaging method was established to monitor VHH and VHH conjugated nanoparticle kinetics in mice using a hybrid approach: kinetics in blood were assessed by direct sampling, and kinetics in kidney, liver, and brain were assessed by serial in vivo NIR imaging. These studies were performed under “basal” circumstances in which the VHH constructs and VHH-conjugated nanoparticles do not substantially interact with targets nor cross the blood brain barrier. Using this approach, we constructed a five-compartment PK model that fits the data well for single VHHs, engineered VHH trimers, and iron oxide nanoparticles conjugated to VHH trimers. The establishment of the feasibility of these methods lays a foundation for future PK studies of candidate brain MRI molecular contrast agents. 相似文献
97.
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99.
为解决在核电施工中雾炮机工作时间过长导致水电资源浪费的问题,以一体化物联网网关为基础,通过多源信息的采集与融合,提出了一种扬尘预测控制算法。该算法根据施工现场和环境情况,从扬尘产生和降尘措施两方面进行量化研究,建立了扬尘预测模型,对扬尘扩散进行预测,并根据预测结果控制雾炮机工作时长,以达到提前降尘和节能的目的。在核电现场进行了对比实验,结果表明,该算法在保障降尘效果基本不变的前提下,节约了60%左右的水电资源。 相似文献
100.
Yehuda Afek Anat Bremler-Barr Haim Kaplan Edith Cohen Michael Merritt 《Distributed Computing》2002,15(4):273-283
A new general theory about restoration of network paths is first introduced. The theory pertains to restoration of shortest paths in a network following failure,
e.g., we prove that a shortest path in a network after removing k edges is the concatenation of at most k+1 shortest paths in the original network. The theory is then combined with efficient path concatenation techniques in MPLS
(multi-protocol label switching), to achieve powerful schemes for restoration in MPLS based networks. We thus transform MPLS
into a flexible and robust method for forwarding packets in a network. Finally, the different schemes suggested are evaluated
experimentally on three large networks (a large ISP, the AS graph of the Internet, and the full Internet topology). These
experiments demonstrate that the restoration schemes perform well in actual topologies.
Received: December 2001 / Accepted: July 2002
RID="*"
ID="*" This research was supported by a grant from the Ministry of Science, Israel 相似文献