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91.
Estimation of Peak Flow Rates for Small Drainage Areas   总被引:1,自引:0,他引:1  
Runoff plots are important for soil loss measurements, and increasing numbers of plots use automatic equipment. To choose equipment with appropriate capacities, the peak flow rate must be known. The peak flow rate is also an important parameter in the modified universal soil loss equation (MUSLE) which calculate the soil loss from upland slope. The available peak flow rate equations are primarily for the watershed scale, not for small drainage areas like runoff plot. This study’s purpose was to derive an equation suitable for the small drainage areas. A total of 149 runoff events on 5 runoff plots were used to develop a peak flow rate equation for the hillslope scale. All plots are located in the Tuanshangou catchment, Zizhou county, Shaanxi province, China. Dimensionless analyses were used to determine the equation form of linear regression analyses. The results revealed that the peak flow rate was significantly correlated with plot area, slope steepness, runoff depth, rainfall depth and the maximum 30-min rainfall intensity. Two equations were developed to estimate peak flow. The model efficiencies of both equations exceeded 0.9. The equations developed in this study represent an important complement to existing peak flow rate equations. These new equations will facilitate the design of soil conservation practices and/or the selection of flow-observation equipment for small drainage areas.  相似文献   
92.
An experimental demonstration is given of a data-based multi-input multi-output (MIMO) feed-forward control design applied to the motion systems of a wafer scanner. Atop a nominal single-input single-output (SISO) feed-forward controller, a MIMO controller is designed having a finite impulse response (FIR) filter structure. The coefficients in this structure are obtained from a gradient approximation-based algorithm. The aid of the FIR filter structure is mostly through its efficient (and limited) set of perturbed-parameter experiments needed to obtain the FIR coefficients. The effectiveness of the optimized feed-forward design in achieving improved servo tracking performances is demonstrated on a high-speed and nano-accurate MIMO wafer stage of an industrial wafer scanner.  相似文献   
93.
A sequentially coupled mathematical thermal-stress model, based on the commercial finite-element code ABAQUS, has been developed to rationalize crack defect formation in fused cast αβ-alumina refractories used in the glass industry. The thermal model was validated against thermocouple and pyrometer measurements obtained in an industrial setting. The temperature predictions obtained from the thermal model were employed as input to the elastic strain-rate-independent plastic stress model. The constitutive behavior of αβ-alumina has been determined over a range of temperatures for input to the stress model. The distribution of β-alumina that forms in the center of the casting due to rejection of Na2O during solidifcation was introduced in the stress model through a user-defined subroutine in order to account for the effect of differences in the thermal contraction behavior and elastic modulus of the αβ- and β-alumina phases. The stress analysis indicates that temperature gradients as well as the different dilatational behavior of the αβ- and β-alumina phases are the main drivers of stress and strain evolution during solidification and subsequent cooling. The β-alumina core, in particular, plays an important role in the generation of tensile stresses and likely gives rise to the generation of the internal cracks observed in industrial castings.  相似文献   
94.
Photosensitizers used normally in treating cancers have considerable potential for treatment of other diseases. One such photosensitizer is the endogenously synthesized photosensitizer protoporphyrin IX (PpIX). To better understand how protoporphyrin might be used in transplantation or in treating autoimmune diseases, information must be obtained on how the photosensitizer affects all immune cells. We used a combination of flow cytometry and in vitro activation assays (recall assays and mixed-lymphocyte reactions) to examine the effects of PpIX on the antigen specific component, lymphocytes and the non-antigen specific component, the macrophages/monocytes and dendritic cells of the immune system. Whereas, lymphocytes accumulate PpIX only when activated, both macrophages and dendritic cells accumulated PpIX immediately, without in vitro activation, as measured by flow cytometry. ALA-PDT (aminolevulenic acid-photodynamic therapy) treated adherent cells in the recall assay had a decreased capability to activate lymphocytes. By increasing the light dose in the recall assay, antigen primed lymphocytes were selectively eliminated from a population of cells. Stimulator cells in an MLR had a decreased stimulatory capacity following ALA-PDT treatment. Functional alterations are seen in both the antigen specific  相似文献   
95.
Members of the fetal-gene-program may act as regulatory components to impede deleterious events occurring with cardiac remodeling, and constitute potential novel therapeutic heart failure (HF) targets. Mitochondrial energy derangements occur both during early fetal development and in patients with HF. Here we aim to elucidate the role of DIO2, a member of the fetal-gene-program, in pluripotent stem cell (PSC)-derived human cardiomyocytes and on mitochondrial dynamics and energetics, specifically. RNA sequencing and pathway enrichment analysis was performed on mouse cardiac tissue at different time points during development, adult age, and ischemia-induced HF. To determine the function of DIO2 in cardiomyocytes, a stable human hPSC-line with a DIO2 knockdown was made using a short harpin sequence. Firstly, we showed the selenoprotein, type II deiodinase (DIO2): the enzyme responsible for the tissue-specific conversion of inactive (T4) into active thyroid hormone (T3), to be a member of the fetal-gene-program. Secondly, silencing DIO2 resulted in an increased reactive oxygen species, impaired activation of the mitochondrial unfolded protein response, severely impaired mitochondrial respiration and reduced cellular viability. Microscopical 3D reconstruction of the mitochondrial network displayed substantial mitochondrial fragmentation. Summarizing, we identified DIO2 to be a member of the fetal-gene-program and as a key regulator of mitochondrial performance in human cardiomyocytes. Our results suggest a key position of human DIO2 as a regulator of mitochondrial function in human cardiomyocytes.  相似文献   
96.
综合地质信息系统及其应用研究   总被引:12,自引:0,他引:12       下载免费PDF全文
针对山区大型边坡与地下工程复杂的稳定性评价与预测问题 ,提出了综合地质信息系统 (SGIS)的框架 ,并建议对一些重要的岩土工程建立SGIS ,以便随时把握工程的全局状态 ,并及时作出进行监控设计与信息化施工的正确决策 ,以适应我国现代化工程建设高速发展的需要。为此 ,开发了专用型的SGIS ,并在文中给出了它在一个大型水电站船闸边坡工程中的应用实例。  相似文献   
97.
We introduce an electrochemical ethylene sensor that employs a thin layer of ionic liquid as electrolyte. Ethylene is oxidized in a potential window starting ~600 mV before the onset of the gold working electrode oxidation, which inhibits the ethylene oxidation at high applied potential. The current amplitude and sensor response time depend on the ionic-liquid film thickness, relative humidity, and applied potential, in agreement with a theoretical model based on diffusion. A detection limit of 760 ppb and a linear response up to 10 ppm were achieved. As illustrated by the detection of ethylene, ionic liquids could serve as an alternative electrolyte for many electrochemical gas sensors that heretofore relied on a strongly acidic electrolyte.  相似文献   
98.
Increased expression and activity of the Ca2+ channel transient receptor potential channel 6 (TRPC6) is associated with focal segmental glomerulosclerosis, but therapeutic strategies to target TRPC6 are currently lacking. Nitric oxide (NO) is crucial for normal glomerular function and plays a protective role in preventing glomerular diseases. We investigated if NO prevents podocyte injury by inhibiting injurious TRPC6-mediated signaling in a soluble guanylate cyclase (sGC)-dependent manner and studied the therapeutic potential of the sGC stimulator Riociguat. Experiments were performed using human glomerular endothelial cells and podocytes. Podocyte injury was induced by Adriamycin incubation for 24 h, with or without the NO-donor S-Nitroso-N-acetyl-DL-penicillamine (SNAP), the sGC stimulator Riociguat or the TRPC6 inhibitor Larixyl Acetate (LA). NO and Riociguat stimulated cGMP synthesis in podocytes, decreased Adriamycin-induced TRPC6 expression, inhibited the Adriamycin-induced TRPC6-mediated Ca2+ influx and reduced podocyte injury. The protective effects of Riociguat and NO were blocked when sGC activity was inhibited with 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) or when TRPC6 activity was inhibited by LA. Our data demonstrate a glomerular (e)NOS-NO-sGC-cGMP-TRPC6 pathway that prevents podocyte injury, which can be translated to future clinical use by, e.g., repurposing the market-approved drug Riociguat.  相似文献   
99.
Rectangular treemaps are often the method of choice to visualize large hierarchical datasets. Nowadays such datasets are available over time, hence there is a need for (a) treemaps that can handle time-dependent data, and (b) corresponding quality criteria that cover both a treemap's visual quality and its stability over time. In recent years a wide variety of (stable) treemapping algorithms has been proposed, with various advantages and limitations. We aim to provide insights to researchers and practitioners to allow them to make an informed choice when selecting a treemapping algorithm for specific applications and data. To this end, we perform an extensive quantitative evaluation of rectangular treemaps for time-dependent data. As part of this evaluation we propose a novel classification scheme for time-dependent datasets. Specifically, we observe that the performance of treemapping algorithms depends on the characteristics of the datasets used. We identify four potential representative features that characterize time-dependent hierarchical datasets and classify all datasets used in our experiments accordingly. We experimentally test the validity of this classification on more than 2000 datasets, and analyze the relative performance of 14 state-of-the-art rectangular treemapping algorithms across varying features. Finally, we visually summarize our results with respect to both visual quality and stability to aid users in making an informed choice among treemapping algorithms. All datasets, metrics, and algorithms are openly available to facilitate reuse and further comparative studies.  相似文献   
100.
The CLARIN Metadata Infrastructure (CMDI) that is being developed in Common Language Resources and Technology Infrastructure (CLARIN) is a computer-supported framework that combines a flexible component approach with the explicit declaration of semantics. The goal of the Dutch CLARIN project “Creating & Testing CLARIN Metadata Components” was to create metadata components and profiles for a wide variety of existing resources housed at two data centres according to the CMDI specifications. In doing so the principles of the framework were tested. The results of the project are of benefit to other CLARIN-projects that are expected to adhere to the CMDI framework and its accompanying tools.  相似文献   
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