http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A Novel Fixed Twin-Rotor Unmanned Aerial Vehicle with Variable Angle Louver Rudder
Yixin Zhang,Jianfeng Zhou,Shaoping Wang,Mengqi Yang,Shaoshi Li 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10
A novel fixed twin-rotor unmanned aerial vehicle (UAV) based on the variable angle louver rudder (VALR) is developed in this work. In view of the mechanical characteristics under the action of the louver rudder, specific kinematics and dynamics models are derived. The aerodynamic characteristics of the UAV are studied through computational fluid dynamics simulation, and a ground measurement system is designed to analyze the aerodynamic characteristics of the prototype. An attitude control model is proposed, and maneuvers such as take-off, landing, hovering, and braking are realized through flight experiments, which verify the feasibility of the prototype design. This research shows that the new layout with the VALR system, combined with the advantages of rudder control and vector control, can reduce the structural complexity and deadweight of the UAV while ensuring flight stability and improving maneuverability. Moreover, the novel UAV has higher energy efficiency and economy.
Zhang, Yixin Korean Society of Plastic and Reconstructive Surge 2012 Archives of Plastic Surgery Vol.39 No.2
Fast improvements in microsurgery have opened new strategies in the field of reconstructive trauma surgery that can be applied to severe elbow trauma management. The disadvantages of pedicle flaps can be overcome in the hand of an experienced trauma surgeon by using free flaps based on the perforators. This provides the patient with the best possible wound cover within the optimal time frame and the treatment of underlying additional structural damage. Although the authors presented only a small number of cases, the results of this study are promising and encourage the use of the ALT flap for the treatment of severe elbow trauma.
( Yixin Luo ),( Zhaorui Liu ),( Jie Liu ),( Yuehua Liu ),( Wei Zhang ),( Yan Zhang ) 대한피부과학회 2020 Annals of Dermatology Vol.32 No.1
Background: Mycosis fungoides (MF) is the most common types of cutaneous T cell lymphoma. It typically presents with erythematous patches and plaques in the early stage and tumors and extracutaneous involvement with possibly fatal outcomes in the late stage. To facilitate early and accurate diagnosis of MF, it is essential to be knowledgeable of classic and variants of this disease. However, there is limited published data in the Chinese population. Objective: To characterize our patient group and to provide additional insight into these malignancies. Methods: Patients diagnosed with mycosis fungoides and its variants from October 2012 to January 2018 were retrospectively analyzed. Disease-specific survival (DSS) rate and curve according to early and advanced stages were also calculated. Results: The mean age at diagnosis of ninety-three MF patients was 38.9±1.73 years (range: 6∼77). Forty-five males (48.4%) and 48 females (51.6 %) were included in this study. The DSS rate of early- stage MF was 98.6%, while that of advanced stage MF was 88.9%. There was a significant difference in DSS rate between early stage and advanced stage MF (p=0.042, logrank test). The median age of 10 patients with hypopigmented MF (hMF) was 10.5 years (range: 6∼28). The age of hMF was younger than that of classical MF patients (p <0.05). Conclusion: Early-stage MF has a better prognosis than advanced stage and hMF affects younger people than classic MF among Chinese. This study provides an insight into mycosis fungoides and its variants in a Chinese population. (Ann Dermatol 32(1) 14∼20, 2020)
Secure and Fine-grained Electricity Consumption Aggregation Scheme for Smart Grid
( Gang Shen ),( Yixin Su ),( Danhong Zhang ),( Huajun Zhang ),( Binyu Xiong ),( Mingwu Zhang ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.4
Currently, many of schemes for smart grid data aggregation are based on a one-level gateway (GW) topology. Since the data aggregation granularity in this topology is too single, the control center (CC) is unable to obtain more fine-grained data aggregation results for better monitoring smart grid. To improve this issue, Shen et al. propose an efficient privacy-preserving cube-data aggregation scheme in which the system model consists of two-level GW. However, a risk exists in their scheme that attacker could forge the signature by using leaked signing keys. In this paper, we propose a secure and fine-grained electricity consumption aggregation scheme for smart grid, which employs the homomorphic encryption to implement privacy-preserving aggregation of users’ electricity consumption in the two-level GW smart grid. In our scheme, CC can achieve a flexible electricity regulation by obtaining data aggregation results of various granularities. In addition, our scheme uses the forward-secure signature with backward-secure detection (FSBD) technique to ensure the forward-backward secrecy of the signing keys. Security analysis and experimental results demonstrate that the proposed scheme can achieve forward-backward security of user’s electricity consumption signature. Compared with related schemes, our scheme is more secure and efficient.
Fundamental Frequency Tracking of Distorted Power Signal Based on the Improved EKF Algorithm
Zhang Xiaobing,Yang Mengchen,Yan Yixin,Fang Guozhi 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.10
To reduce the impacts of harmonics and noises on frequency measurements, a novel method of frequency tracking is presented based on improved EKF algorithm and wavelet transform. Firstly, the power signal was preprocessed to extract the fundamental wave by wavelet filtering. Then, an improved Extended Kalman Filter was introduced to achieve fast and accurate frequency tracking. By adding a robust factor and modifying the covariance matrix in real time, it enhanced the stability for detecting distorted signals. The proposed tracking algorithm can effectively solve the problems of traditional Extended Kalman Filter such as lack of adaptability, instability and divergence. And it improved the tracking speed and accuracy. Finally, Detailed simulations on several typical models of power signals have been carried out and the Simulation results shown that the new algorithm increases the speed, convergence and accuracy. It effectively suppresses the impacts of harmonics and noises on the frequency tracking results.
Yixin Xu,Fulai Liu,Zixuan Zhang,Zhenxing Sun 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.1
In this article, the uplink achievable rate is investigated for massive multiple-input multiple-output (MIMO) under correlated Ricean fading channel, where each base station (BS) and user are both deployed multiple antennas. Considering the availability of prior knowledge at BS, two different channel estimation approaches are adopted with and without prior knowledge. Based on these channel estimations, a two-layer decoding scheme is adopted with maximum ratio precoding as the first layer decoder and optimal second layer precoding in the second layer. Based on two aforementioned channel estimations and two-layer decoding scheme, the exact closed form expressions for uplink achievable rates are computed with and without prior knowledge, respectively. These derived expressions enable us to analyze the impacts of line-of-sight (LoS) component, two-layer decoding, data transmit power, pilot contamination, and spatially correlated Ricean fading. Then, numerical results illustrate that the system with spatially correlated Ricean fading channel is superior in terms of uplink achievable rate. Besides, it reveals that compared with the single-layer decoding, the two-layer decoding scheme can significantly improve the uplink achievable rate performance.
Yixin Leng,Yun Zhang,Chunxiang Huang,Xiaocheng Liu,Yuzhen Wu 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.4
The solid super acid catalyst SO4 2−/ZrO2 was prepared by impregnation method using ZrO2 as the catalyst support. Catalyst forming was taken into consideration in order to separate catalyst from the mixture of cellulose acetate propionate (CAP). Al2O3 and sesbania gum powder were selected as binding agent and auxiliary agent respectively. The catalytic properties were evaluated through esterification of cellulose with acetic anhydride, propionic anhydride and characterized by XRD, FTIR and NH3-TPD. In this paper, the effects of concentration of H2SO4 impregnated, calcination temperature, esterification temperature and esterification time on the yield, acyl content and viscosity of CAP were investigated. The results showed that SO4 2−/ZrO2 successfully catalyzed CAP synthesis over catalysts impregnated in 0.75 mol/L H2SO4 and calcined at 500 oC. The yield, acetyl content and propionyl content of CAP reached the maximum value of 105.3%, 29.9% and 25.8% reacted at 50 oC for 8 h.
Solubility of 5-mercapto-1-methyltetrazole in pure solvents from (283 to 329) K
Lin Zhang,Yixin Qu,Yongze Wang 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.4
The solubility of 5-mercapto-1-methyltetrazole in pure solvents from (283 to 329) K was measured using a laser monitoring observation technique at atmospheric pressure. The solubility data were accurately correlated by a modified Apelblat equation. The calculated results of which are proved to show fine representation of experimental data.
Xin Zhang,Qi Feng,Jiping Zhao,Hong-liang Liu,Jichao Li,Yixin Xiao,Fan Li,Qingmei Lu 한국물리학회 2020 Current Applied Physics Vol.20 No.1
Sr-doped single crystals (C1-xSx)12A7:e− (x=0, 0.01, 0.02, 0.03) were successfully fabricated by floating zone method. It is found that Sr-doping decreases the reduction time from 30 h to 20 h. The maximum emission current of (C1-xSx)12A7:e− is greatly improved by 50% than that of the un-doped. The DFT calculations show Srdoping in C12A7 contributed to the free O2− in the cages spread out, leading to a short reduction time; increase the “window” between two adjacent cages that is conducive to the electrons in cages to escape. And the work function of the (C1-xSx)12A7:e− is lower than that of C12A7:e−.