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RISS 인기검색어
- 검색키워드
- 저자 : Yuanping Zhou (검색결과 5 건)
- 무료
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Yuanping Xu,Jin Zhou,Chaowu Jin,Qintao Guo 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.7
The stiffness and damping coefficients of Active magnetic bearings (AMBs) have a great impact on the dynamics of a high-speed rotor AMB system, from its bending critical speed to the modes of its vibration and stability. To accurately obtain the stiffness and damping coefficients of AMBs, this study proposes a new identification approach based on the transfer matrix model updating method. By minimizing the error between the unbalance response calculated through the transfer matrix approach and the experimental measurements, the stiffness and damping coefficients are obtained using the simplex optimization algorithm based on the updating method of the model. According to the experimental data, we identify the parameters from 20 Hz to 260 Hz (1200 rpm to 15600 rpm). To verify the identified results, a finite element rotor AMBs model is created, and the theoretical unbalance response is predicted using the identified parameters. The theoretical unbalance responses closely coincide with the experimental measurements, indicating the effectiveness of the proposed method.
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Yuanping Xu,Jin Zhou,Chaowu Jin 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.2
The dynamic rotor behavior is significantly affected by the stiffness and damping characteristics of the bearings. Therefore, it is important to identify these bearing parameters. For active magnetic bearings (AMBs), these bearing parameters not only could be identified from rotor dynamic response, but also from electrical control system transfer function. Some identification works from rotor dynamic response have been reported, but identification from electrical control system transfer function is relatively few. In this paper, we deduced the equivalent stiffness and damping expressions with electrical control system transfer function for rotor AMBs and identified these values from electrical control system model. To evaluate the identified results, previous reported results from rotor dynamic response is employed for comparison. We found that for the stiffness, a complete and precise electrical control model will obtain relatively consistent values; however, for the damping, the accurate electrical control model is still not enough and the eddy current loss should be included.
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Opportunistic Beamforming Communication With Throughput Analysis Using Asymptotic Approach
Minghua Xia,Yuanping Zhou,Ha, J.,Hyun Kyu Chung IEEE 2009 IEEE Transactions on Vehicular Technology VT Vol.58 No.5
<P>The opportunistic beamforming system (OBS) is currently receiving much attention in the field of downlink beamforming due to its simple random beamforming, low feedback complexity, and same throughput scaling obtained with perfect channel-state information using dirty paper coding at the transmitter. In this paper, we focus on its closed-form throughput evaluation over Rayleigh fading channels, based on the asymptotic theory of extreme order statistics. First, the throughput of a single-beam OBS is investigated, and an analytical solution tighter than the previously reported one is derived. Then, the asymptotic throughput bounds on a multibeam OBS are presented, and also, our analytical expression is shown to be very tight with the simulation results even with fewer users. After that, we argue that the reported conclusion that the single-beam OBS is much preferable to the multibeam OBS in the high-signal-to-noise-ratio (SNR) regime is inaccurate, but that, instead, it is satisfied only when the number of users is very small, due to its limited multiuser diversity gain. Finally, we show that four transmit beams is the most preferable in the multibeam OBS with a large number of users and moderate SNR, which arrives at the tradeoff between increasing spatial multiplexing gain and disappearing multiuser diversity gain.</P>
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Dongjie Zhang,Li Mei,Yuanping Hao,Bingcheng Yi,Jilin Hu,Danyang Wang,Yaodong Zhao,Zhe Wang,Hailin Huang,Yongzhi Xu,Xuyang Deng,Cong Li,Xuewei Li,Qihui Zhou,Yun Lu 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00
Background Clinical tissue adhesives remain some critical drawbacks for managing emergency injuries, such as inadequate adhesive strength and insufficient anti-infection ability. Herein, a novel, self-healing, and antibacterial carboxymethyl chitosan/polyaldehyde dextran (CMCS/PD) hydrogel is designed as the first-aid tissue adhesive for effective trauma emergency management. Methods We examined the gel-forming time, porosity, self-healing, antibacterial properties, cytotoxicity, adhesive strength, and hemocompatibility. Liver hemorrhage, tail severance, and skin wound infection models of rats are constructed in vivo, respectively. Results Results demonstrate that the CMCS/PD hydrogel has the rapid gel-forming (~ 5 s), good self-healing, and effective antibacterial abilities, and could adhere to tissue firmly (adhesive strength of ~ 10 kPa and burst pressure of 327.5 mmHg) with excellent hemocompatibility and cytocompatibility. This suggests the great prospect of CMCS/ PD hydrogel in acting as a first-aid tissue adhesive for trauma emergency management. The CMCS/PD hydrogel is observed to not only achieve rapid hemostasis for curing liver hemorrhage and tail severance in comparison to commercial hemostatic gel (Surgiflo ®) but also exhibit superior anti-infection for treating acute skin trauma compared with clinical disinfectant gel (Prontosan ®). Conclusions Overall, the CMCS/PD hydrogel offers a promising candidate for first-aid tissue adhesives to manage the trauma emergency. Because of the rapid gel-forming time, it could also be applied as a liquid first-aid bandage for mini-invasive surgical treatment.
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Effects of Sulfur Introduction on the UV and the Visible Emission Properties of ZnO
Hongying Guo,Feihong Jiang,Run Yuan,Jun Zhang,Yuanping Sun,Yifan Liu,Yongxin Qiu,Taofei Zhou,Xionghui Zeng,Baoshun Zhang,Ke Xu,Hui Yang 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.4
Hexagonal ZnO particles have been synthesized by using the hydrothermal method with differentsulfur concentrations in the reaction solutions. Structural and optical characterizations have beenconducted to study the effects of the sulfur in the reaction solutions on the properties of thesynthesized ZnO in the ultraviolet (UV) and the visible (VIS) bands. The existance of sulfur inthe solutions can help to introduce compression strain along the a axis and an opposite trend forthe parameter c with strain inside the formed ZnO particles, which means the total strain in thesamples is presented along the c axis. The average size of the ZnO particles, as calculated fromSEM images, shows the same trend as the strain in the samples. The increasing incorporation ofsulfur causes an increase in the VIS luminescence band, which can be attributed to an increase inthe number of sulfur-induced defects.
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