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RISS 인기검색어
- 검색키워드
- 저자 : Mengda Liu (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
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Frequency Up-convert Energy Harvester for Automobiles
Mengda Liu,Rencheng Zheng,Kimihiko Nakano 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.춘계 No.-
In the last decade, vibration energy harvesting as a green energy source has received significant attention. Hence, this study concentrates on a piezoelectric-based low frequency vibration energy harvester using frequency up-conversion techniques for automobile applications. Magnetic force is used to induce impulses to excite the beam, and the related dynamic equations are derived. Owe to the attraction of the magnets, a two-stage vibration occurs during the experimental study, which can be acted as an enhancing method for low frequency vibration energy harvesting. Numerical simulations and experiments have been carried out to validate that the proposed system can up-convert frequency to harvest more power.
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Zicheng Ma,Zifeng Han,Zhaohu Liu,Fanliang Meng,Hongyu Wang,Longlong Cao,Yan Li,Qiulin Jiao,Sidang Liu,Mengda Liu 대한수의학회 2020 Journal of Veterinary Science Vol.21 No.3
Background: Pseudorabies, also known as Aujeszky's disease, is caused by the pseudorabies virus (PRV) and has been recognized as a critical disease affecting the pig industry and a wide range of animals around the world, resulting in great economic losses each year. Shandong province, one of the most vital food animal-breeding regions in China, has a very dense pig population, within which pseudorabies infections were detected in recent years. The data, however, on PRV epidemiology and coinfection rates of PRV with other major swine diseases is sparse. Objectives: This study aimed to investigate the PRV epidemiology in Shandong and analyze the current control measures. Methods: In this study, a total number of 16,457 serum samples and 1,638 tissue samples, which were collected from 362 intensive pig farms (≥ 300 sows/farm) covered all cities in Shandong, were tested by performing enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). Results: Overall, 52.7% and 91.5% of the serum samples were positive for PRV-gE and -gB, respectively, based on ELISA results. In addition, 15.7% of the tissue samples were PCR positive for PRV. The coinfection rates of PRV with porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus, and classical swine fever virus were measured; coinfection with PCV2 was 35.0%, higher than those of the other two viruses. Macroscopic and microscopic lesions were observed in various tissues during histopathological examination. Conclusions: The results demonstrate the PRV prevalence and its coinfection rates in Shandong province and indicate that pseudorabies is endemic in pig farms in this region. This study provides epidemiological data that can be useful in the prevention and control of pseudorabies in Shandong, China.
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Excessive copper in feed not merely undermines animal health but affects food safety
Zicheng Ma,Yan Li,Zifeng Han,Zhaohu Liu,Hongyu Wang,Fanliang Meng,Sidang Liu,Dawei Chen,Mengda Liu 대한수의학회 2021 Journal of Veterinary Science Vol.22 No.3
Background: Blackened intestines in slaughtered pigs have been commonly observed in China in recent years. However, no cause has been reported. Objectives: We attempted to determine whether the blackening of the pig intestine was related to an excess of copper (Cu) in their feed. Methods: In this study, we observed and collected porcine intestines in small- and large-scale pig slaughterhouses in Shandong province from May to October 2018. Twelve types of metal ions were detected in the black intestinal samples. Results: The Cu level in the intestine samples was mostly higher than the Chinese national limit for food. Further study showed that Cu supplementation in most commercial porcine feed also exceeded the national standard. An animal model (mouse) that could mimic the intestinal blackening in pigs was established. Compared to control mice, Cu accumulated in the liver and intestines of mice fed an excessive Cu level, confirming the excessive Cu in the feed may be considered the major cause of blackened porcine intestines. Microscopic examination revealed that black intestines had many particles containing Cu in the lamina propria of the intestinal mucosa, and the intestinal mucosal epithelial cells showed degeneration and necrosis. Conclusions: In conclusion, overuse of Cu in animal feed can lead to animal poisoning and Cu accumulation in animal products. Such overuse not only harms the health of livestock but can also affect public health.
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