El problema estès de dos cossos

Treballs Finals de Grau de Matemàtiques, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2018, Director: Antoni Benseny[en] This memory is about the extended problem of two bodies using the physical concepts and the mathematical branches as numerical methods and differential equations. After the reduction of the problem, we analyze the main theoretical part. In the following chapter, based on the results obtained, we will focus on the Kepler problem that studies the behaviors of the orbits in the gravitational case. In the end, with a simulator we can visualize the movement of these two bodies for extended problems

PARTNER: Level up the Polar Representation for LiDAR 3D Object Detection

Recently, polar-based representation has shown promising properties in perceptual tasks. In addition to Cartesian-based approaches, which separate point clouds unevenly, representing point clouds as polar grids has been recognized as an alternative due to (1) its advantage in robust performance under different resolutions and (2) its superiority in streaming-based approaches. However, state-of-the-art polar-based detection methods inevitably suffer from the feature distortion problem because of the non-uniform division of polar representation, resulting in a non-negligible performance gap compared to Cartesian-based approaches. To tackle this issue, we present PARTNER, a novel 3D object detector in the polar coordinate. PARTNER alleviates the dilemma of feature distortion with global representation re-alignment and facilitates the regression by introducing instance-level geometric information into the detection head. Extensive experiments show overwhelming advantages in streaming-based detection and different resolutions. Furthermore, our method outperforms the previous polar-based works with remarkable margins of 3.68% and 9.15% on Waymo and ONCE validation set, thus achieving competitive results over the state-of-the-art methods.Comment: ICCV 202

Interferon-alpha responsible EPN3 regulates hepatitis B virus replication

Hepatitis B virus (HBV) infection remains a major health problem worldwide, and the current antiviral therapy, including nucleoside analogs, cannot achieve life-long cure, and clarification of antiviral host immunity is necessary for eradication. Here, we found that a clathrin-binding membrane protein epsin3 (EPN3) negatively regulates the expression of HBV RNA. EPN3 expression was induced by transfection of an HBV replicon plasmid, and reduced HBV-RNA level in hepatic cell lines and murine livers hydrodynamically injected with the HBV replicon plasmid. Viral RNA reduction by EPN3 was dependent on transcription, and independent from epsilon structure of viral RNA. Viral RNA reduction by overexpression of p53 or IFN-α treatment, was attenuated by knockdown of EPN3, suggesting its role downstream of IFN-α and p53. Taken together, this study demonstrates the anti-HBV role of EPN3. The mechanism how it decreases HBV transcription is discussed

Efficient Facilitated Transport Polymer Membrane for CO2/CH4 Separation from Oilfield Associated Gas

CO2 enhanced oil recovery (CO2-EOR) technology is a competitive strategy to improve oil field economic returns and reduce greenhouse gas emissions. However, the arbitrary emissions or combustion of the associated gas, which mainly consists of CO2 and CH4, will cause the aggravation of the greenhouse effect and a huge waste of resources. In this paper, the high-performance facilitated transport multilayer composite membrane for CO2/CH4 separation was prepared by individually adjusting the membrane structure of each layer. The effect of test conditions on the CO2/CH4 separation performance was systematically investigated. The membrane exhibits high CO2 permeance of 3.451 × 10−7 mol·m−2·s−1·Pa−1 and CO2/CH4 selectivity of 62 at 298 K and 0.15 MPa feed gas pressure. The cost analysis was investigated by simulating the two-stage system. When the recovery rate and purity of CH4 are 98%, the minimum specific cost of separating CO2/CH4 (45/55 vol%) can be reduced to 0.046 $·Nm−3 CH4. The excellent short-to-mid-term stability indicates the great potential of large industrial application in the CH4 recovery and CO2 reinjection from oilfield associated gas

A practical pressure measuring method for the upper urinary tract during ureteroscopy

Purpose: The purpose of this study was to develop and test a method for measuring pressure in the upper urinary tract during ureteroscopic operations and to evaluate its efficacy and clinical significance. Methods: A total of 44 patients, each with a ureteral calculus in the proximal ureteral segment, were enrolled in the study group: 21 patients with an acute and 23 with a chronic obstruction. The ureteroscope was passed forward to the upper segment of the obstructed ureter immediately after the calculus was broken and the intraluminal ureteral pressure was then transmitted along with the irrigant flow (0.9% sodium chloride). Results: The mean ureteral pressures of the acute obstruction subgroup, the chronic obstruction subgroup and the control group were 74.5 mmHg (22-180 mmHg), 32.5 mmHg (9-53 mmHg) and 10.2 mmHg (8-13 mmHg), respectively. A significant correlation was found between ureteral pressure and the following indexes: the duration of the obstruction (r=0.985), the diameter of the ureter above the calculus (r=0.878) and the depth of the hydronephrosis of the renal pelvis (r=0.862). No associations were observed between the pressure and the serum creatinine level (r=0.214) or the urinary leukocyte count (r=0.047). The intraluminal pressure correlated with the glomerular flow rate (GFR) of the affected kidney (r =0.975, P =0.001). Conclusions: This new method is non-invasive, practical and reproducible. Measuring the intraluminal pressure of the ureter can provide a valuable index to quantify the severity of the obstruction of the upper urinary tract, which is helpful for the prediction of the affected renal function prognosis

Efficient Facilitated Transport Polymer Membrane for CO₂/CH₄ Separation from Oilfield Associated Gas

CO2 enhanced oil recovery (CO2-EOR) technology is a competitive strategy to improve oil field economic returns and reduce greenhouse gas emissions. However, the arbitrary emissions or combustion of the associated gas, which mainly consists of CO2 and CH4, will cause the aggravation of the greenhouse effect and a huge waste of resources. In this paper, the high-performance facilitated transport multilayer composite membrane for CO2/CH4 separation was prepared by individually adjusting the membrane structure of each layer. The effect of test conditions on the CO2/CH4 separation performance was systematically investigated. The membrane exhibits high CO2 permeance of 3.451 × 10−7 mol·m−2·s−1·Pa−1 and CO2/CH4 selectivity of 62 at 298 K and 0.15 MPa feed gas pressure. The cost analysis was investigated by simulating the two-stage system. When the recovery rate and purity of CH4 are 98%, the minimum specific cost of separating CO2/CH4 (45/55 vol%) can be reduced to 0.046 $·Nm−3 CH4. The excellent short-to-mid-term stability indicates the great potential of large industrial application in the CH4 recovery and CO2 reinjection from oilfield associated gas