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368 results on '"Yan, Liwei"'

33. A 31–36 GHz low noise‐variable gain amplifier with less than 0.37° RMS phase error and 0.4 dB gain step in 65‐nm CMOS.

Author

Kuai, Yang, Yan, Liwei, Liu, Mingjie, and Yang, Fei

Subjects
*COMPLEMENTARY metal oxide semiconductors, *CAPACITORS, *NOISE
Abstract

This article realizes a low noise‐variable gain amplifier (LN‐VGA) operating at the frequency range of 31–36 GHz. The LN‐VGA consists of two amplifier stages and a gain control stage. To achieve low noise and high gain, the two amplifier stages were implemented using a single‐ended inductive source‐degeneration cascaded with pseudo‐differential neutralization capacitors. Moreover, a symmetrical splitting cascode unit topology is proposed in the gain control stage to improve the precision of phase variation and gain step within the 3‐dB bandwidth. The LN‐VGA was fabricated using a 65‐nm CMOS process, demonstrating a gain control range of 15.2–21.2 dB with less than 2° phase variation and a minimum noise figure of 5.6 dB. The measured results show less than 0.37° rms phase error and a 0.4 dB gain step at 31–36 GHz. The chip occupies an area of 0.81 × 0.51 mm2 excluding pads and consumes 27 mW of power. [ABSTRACT FROM AUTHOR]

Published
2024
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34. The effects of food on the pharmacokinetics of mycophenolate mofetil in healthy horses.

Author

Bello, Kaitlyn, Lorch, Gwendolen, Papich, Mark G., Kim, Kyeongmin, Toribio, Ramiro E., Yan, Liwei, Xie, Zhiliang, Hill, Kasey, and Phelps, Mitch A.

Subjects
MYCOPHENOLIC acid, PHARMACOKINETICS, HORSES, HORSE diseases, VETERINARY medicine
Abstract

Additional immunomodulatory treatment is needed for the management of immune‐mediated disease in horses. Mycophenolate mofetil (MMF) is an immunomodulatory agent used in human and veterinary medicine for the prevention of graft rejection and the management of autoimmune diseases. Few studies exist investigating the pharmacokinetics of MMF in horses. The aim of this study was to evaluate the pharmacokinetics of a single dose of MMF in healthy horses in the fed vs. fasted state. Six healthy Standardbred mares were administered MMF 10 mg/kg by a nasogastric (NG) tube in a fed and fasted state. A six‐day washout period was performed between the two doses. No statistically significant differences in mycophenolic acid (MPA) concentrations were seen at any time point apart from 8 h, when plasma metabolite concentrations were significantly higher in the fasted state compared to the fed state (p =.038). Evidence of enterohepatic recirculation was seen only in the fasted state; this did not yield clinical differences in horses administered a single‐dose administration but may be significant in horses receiving long‐term MMF treatment. [ABSTRACT FROM AUTHOR]

Published
2024
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41. A comparison of ablative resistance properties of liquid silicone rubber composites filled with different fibers

Author

Zhang, Hao, Yan, Liwei, Zhou, Shengtai, Zou, Huawei, Chen, Yang, Liang, Mei, and Ren, Xiancheng

Subjects
Silicone rubber -- Mechanical properties -- Thermal properties, Carbon fibers -- Mechanical properties -- Thermal properties, Engineering and manufacturing industries, Science and technology
Abstract

Flexible ablative materials play a key role in thermal protection systems to protect space vehicles during hypersonic flight missions. In this work, epoxy resin modified liquid silicone rubber was adopted as elastomeric matrix. Two inorganic fibers (carbon fibers (CF) and quartz fibers (QF)) and two organic fibers (aramid fibers (AF) and poly (p-phenylene benzobisoxazole) fibers (PBO)) were chosen as functional fillers. The ablation resistance and thermal insulation properties were evaluated using oxyacetylene torch test. Microstructure and phase composition of the char layer was fully characterized to investigate the ablation mechanism. SEM observations revealed that the fibers are well dispersed and integrated in the matrix. TGA analysis indicated that the inorganic fibers possess significantly higher thermal stability than organic fibers. In addition, a molten silica film can be formed on the material surface, which can exert a better thermal protection effect on the matrix. Furthermore, the ablation test shows that the linear ablation rate decreases first and then increases with an increase of fiber content. This work provides basic data to guide optimal selection of fibrous ablatives to enhance ablation performance. KEYWORDS ablation resistance, fibers, liquid silicone rubber, thermal insulation, 1 | INTRODUCTION Ablative materials are the base of thermal protection system (TPS), which supports the rapid development of the entire aerospace technology. These sacrificial materials are extensively employed to [...]

Published
2021
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