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To investigate the performance of transcritical CO2 quasi-secondary compression cycle with ejector (TCIEJ) for heat pump water heaters, the thermodynamic model of TCIEJ is established based on the pinch point, and TCEX, TCEJ, and TCI are selected as comparisons. The effects of changing high pressure and ambient temperature on the heating COP and compressor exhaust temperature are analyzed, and the influence of cooling water inlet and outlet temperature and vapor injection pressure on TCIEJ is further analyzed. The results show that there are optimal high pressures that make the heating COP of the four heat pump cycles reach the maximum value, of which TCIEJ has the best performance. At an ambient temperature of −15 °C, the maximum heating COP of TCIEJ increased by about 20.5%, 14.9%, and 7.9% compared with TCEX, TCEJ, and TCI. With the increase in ambient temperature, the optimal high pressure continues to increase, and the corresponding maximum heating COP gradually increases. Selecting the geometric mean of high pressure and evaporation pressure as the optimal vapor injection pressure for TCIEJ, the error is small compared to the actual optimal vapor injection pressure. With the increase in ambient temperature and cooling water outlet temperature, the optimal high pressure of TCIEJ continues to increase, and the correlation formula of optimal high pressure is fitted according to the simulation results. [ABSTRACT FROM AUTHOR]

In order to improve the efficiency of the system and promote its application in other industries, the performance of a thermoelectric subcooled CO2 transcritical heat pump system was studied. A simulation model of the system was established using steady-state lumped parameter technology, and the experimental data were compared with the simulation results. The effects of cooling and chilled water flow rate and temperature, subcooling degree, compressor discharge pressure on the coefficient of performance (COP), and heating coefficient of performance (COPh) were analyzed. The results showed that COP/COPh increased with the increase in cooling and chilled water flow rate and chilled water temperature and decreased with the increase in cooling water temperature. The experimental COPh and COP of the system with a thermoelectric subcooler increased by 4.19% and 4.62%, respectively, compared to the system without it. The simulated data was in good agreement with the experimental data, and the error was within 10%, thus verifying the correctness of the model. When the subcooling degree increased to 11 °C, the system simulation results showed that COP/COPh increased by about 40% and 13.3%, respectively. The optimal high pressure was about 8.0 MPa, which corresponded to the maximum COP and COPh of the system of 3.25 and 4.25, respectively. The research results can provide a theoretical basis for future system optimization. [ABSTRACT FROM AUTHOR]

Oil well cement additives applied in high-temperature environments play an increasingly important role in well cementing work. In this study, a ternary copolymer LNS-1 consisting of sodium styrene sulfonate (SSS), maleic acid (MA), and N-vinylcaprolactam (NVCL) was designed and synthesized using potassium persulfate as an initiator via free radical aqueous solution copolymerization, which was then used as a retarder additive for oil well cement under high-temperature conditions. The structure and performance of copolymer LNS-1 was assessed via gel permeation chromatography, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, nuclear magnetic resonance hydrogen spectrum, Thermogravimetric analysis, and scanning electron microscopy analysis. To study the effect of the retarder on cement slurry properties, the performance of the slurry with LNS-1 was tested. The experimental results demonstrate that LNS-1 was successfully synthesized with excellent retarding ability, thermal resistance, and outstanding suspension; thus, the copolymer can serve as an excellent retarder for oil well cement. Through exploration, it is found that the mechanism of the retarder mainly includes adsorption – membrane layer mechanism and chelation – covering mechanism. NVCL exhibits good complexation, adsorption, hydrolysis stability, and thermal stability. It contains three lone pairs of electrons, which allow the NVCL to chelate Ca2+ that in the liquid phase of the cement. The number of calcium ions is therefore reduced in the cement liquid phase, and cement hydration is inhibited to a certain extent, contributing to a longer hydration process. [ABSTRACT FROM AUTHOR]

Video stabilization is an important technique in digital cameras. Its impact increases rapidly with the rising popularity of handheld cameras and cameras mounted on moving platforms (e.g., cars). Stabilization of two images can be viewed as an image registration problem. However, to ensure the visual quality of the whole video, video stabilization has a particular emphasis on the accuracy and robustness over long image sequences. In this paper, we propose a novel technique for video stabilization based on the particle filtering framework. We extend the traditional use of particle filters in object tracking to tracking of the projected affine model of the camera motions. We rely on the inverse of the resulting image transform to obtain a stable video sequence. The correspondence between scale-invariant feature transform points is used to obtain a crude estimate of the projected camera motion. We subsequently postprocess the crude estimate with particle filters to obtain a smooth estimate. It is shown both theoretically and experimentally that particle filtering can reduce the error variance compared to estimation without particle filtering. The superior performance of our algorithm over other methods for video stabilization is demonstrated through computer simulated experiments. Index Terms--Bootstrap filtering, Monte Carlo methods, motion analysis, particle filtering, video stabilization.

Abstract Background Oxaliplatin, an effective antineoplastic agent againstgastrointestinal tumors, can cause severe peripheral neurotoxicity, which seriously limits its clinical application. To date, there are no effective treatments for this complication. Ganglioside-monosialic acid (GM1) has been shown to protect neurons against injuries and degeneration. The aim of this study was to evaluate the effects of GM1 on preventing oxaliplatin-induced neurotoxicity in patients with gastrointestinal tumors. Methods In this study, 120 patients with gastrointestinal tumors were enrolled, andthey received the treatment of XELOX (oxaliplatin and capecitabine) and FOLFOX4 (oxaliplatin, leukovolin and 5-fluorouracil). The patients were randomly divided into two groups, the experimental group and control group, with60 patients ineach. On the day chemotherapy was initiated, the experimental group received GM1 intravenously (100 mg once daily) for 3 days, while no neuroprotective agents were applied in the control group. The incidence rates and classification of neurotoxicity in the two groups were evaluated and the differences between the two groups were examined. Furthermore, whether GM1 affected the therapeutic effects of chemotherapy was also examined. Results The grade of neurotoxicity in the experimental group was significantly lower than in the control group (P Conclusion The data suggested that GM1 could reduce the grade of oxaliplatin-induced neurotoxicity and was an effective neuroprotective agent against oxaliplatin-induced high-grade neurotoxicity in patients with gastrointestinal tumors.