http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Fanghua Liu (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
-
Trophic strategy of diverse methanogens across a river-to-sea gradient
Bingchen Wang,Fanghua Liu,Shiling Zheng,Qinqin Hao 한국미생물학회 2019 The journal of microbiology Vol.57 No.6
Methanogens are an important biogenic source of methane, especially in estuarine waters across a river-to-sea gradient. However, the diversity and trophic strategy of methanogens in this gradient are not clear. In this study, the diversity and trophic strategy of methanogens in sediments across the Yellow River (YR) to the Bohai Sea (BS) gradient were investigated by high-throughput sequencing based on the 16S rRNA gene. The results showed that the diversity of methanogens in sediments varied from multitrophic communities in YR samples to specific methylotrophic communities in BS samples. The methanogenic community in YR samples was dominated by Methanosarcina, while that of BS samples was dominated by methylotrophic Methanococcoides. The distinct methanogens suggested that the methanogenic community of BS sediments did not originate from YR sediment input. High-throughput sequencing of the mcrA gene revealed that active Methanococcoides dominated in the BS enrichment cultures with trimethylamine as the substrate, and methylotrophic Methanolobus dominated in the YR enrichment cultures, as detected to a limited amount in in situ sediment samples. Methanosarcina were also detected in this gradient sample. Furthermore, the same species of Methanosarcina mazei, which was widely distributed, was isolated from the area across a river-to-sea gradient by the culture-dependent method. In summary, our results showed that a distribution of diverse methanogens across a river-to-sea gradient may shed light on adaption strategies and survival mechanisms in methanogens.
-
Shiling Zheng,Bingchen Wang,Fanghua Liu,Oumei Wang 한국미생물학회 2017 The journal of microbiology Vol.55 No.11
Minerals that contain ferric iron, such as amorphous Fe(III) oxides (A), can inhibit methanogenesis by competitively accepting electrons. In contrast, ferric iron reduced products, such as magnetite (M), can function as electrical conductors to stimulate methanogenesis, however, the processes and effects of magnetite production and transformation in the methanogenic consortia are not yet known. Here we compare the effects on methanogenesis of amorphous Fe (III) oxides (A) and magnetite (M) with ethanol as the electron donor. RNAbased terminal restriction fragment length polymorphism with a clone library was used to analyse both bacterial and archaeal communities. Iron (III)-reducing bacteria including Geobacteraceae and methanogens such as Methanosarcina were enriched in iron oxide-supplemented enrichment cultures for two generations with ethanol as the electron donor. The enrichment cultures with A and non-Fe (N) dominated by the active bacteria belong to Veillonellaceae, and archaea belong to Methanoregulaceae and Methanobacteriaceae, Methanosarcinaceae (Methanosarcina mazei), respectively. While the enrichment cultures with M, dominated by the archaea belong to Methanosarcinaceae (Methanosarcina barkeri). The results also showed that methanogenesis was accelerated in the transferred cultures with ethanol as the electron donor during magnetite production from A reduction. Powder X-ray diffraction analysis indicated that magnetite was generated from microbial reduction of A and M was transformed into siderite and vivianite with ethanol as the electron donor. Our data showed the processes and effects of magnetite production and transformation in the methanogenic consortia, suggesting that significantly different effects of iron minerals on microbial methanogenesis in the iron-rich coastal riverine environment were present.
-
Modeling and Verification of a Contactless Air Film Conveyor Using a Viscous Traction Principle
Wei Zhong,Xiaoyu Gu,Ke Xu,Fanghua Liu,Xin Li,Toshiharu Kagawa 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.12
Many industries require contactless transport of delicate or clean products such as silicon wafers, flat foodstuffs and freshly painted objects. In this study, a contactless air film conveyor for flat objects is introduced. The object is supported by a thin film formed between the object and the conveyor surface and transported by viscous traction which is generated by controlled airflow underneath the object. Experiments are conducted to investigate the film pressure distribution and viscous force. The results show that the film pressure is symmetrically distributed along the direction perpendicular to the airflow in the actuating cells and non-symmetrically distributed along the airflow direction. The viscous force decreases as the increase of gap thickness. A simplified model is established to help understand and characterize the viscous force. The calculated results show a good agreement with the experimental data. It is revealed that the viscous force is the resultant of an actuating force in the pocket and side areas and a drag force from airflow across the dam area. Simulation and experiments are conducted using a PID controller for one dimension position control and position tracking. The results verify the effectiveness of the theoretical modeling and control method.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
