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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第8期12卷 687-697页

作者： sun Hee KIM Hyung Jeong YAng Kam Swee ng Department of Computer Science Chonnam National University

Missing values occur in bio-signal processing for various reasons,including technical problems or biological *** missing values are then either simply excluded or substituted with estimated values for further *** the missing signal values are estimated for electroencephalography (EEG) signals,an example where electrical signals arrive quickly and successively,rapid processing of high-speed data is required for immediate decision *** this study,we propose an incremental expectation maximization principal component analysis (iEMPCA) method that automatically estimates missing values from multivariable EEG time series data without requiring a whole and complete data *** proposed method solves the problem of a biased model,which inevitably results from simply removing incomplete data rather than estimating them,and thus reduces the loss of information by incorporating missing values in real *** using an incremental approach,the proposed method alsominimizes memory usage and processing time of continuously arriving *** results show that the proposed method assigns more accurate missing values than previous methods.

关键词： Electroencephalography (EEG) Missing value imputation Hidden pattern discovery Expectation maximization Principal component analysis

Design and control of deformable quadrotor with varying length arms

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Science China(Technological Sciences) 2023年第5期66卷 1225-1234页

作者： sun YiChong XIE MingNa LI YeHui ng WingYin ZHAng Heng LI Zheng Multi-Scale Medical Robotics Centre The Chinese University of Hong KongHong Kong 999077China Department of Surgery The Chinese University of Hong KongHong Kong 999077China Department of Electrical and Electronic Engineering The University of Hong KongHong Kong 999077China College of Optoelectronic Engineering Chongqing UniversityChongqing 400044China

Deformable quadrotors can manipulate their specific structure for specialized tasks or excellent flight performance under diverse *** added deformation mechanism,the quadrotor exhibits higher flexibility;however,this is accompanied by difficulties in modeling analysis and controller design,which are crucial ***,a novel deformable quadrotor that can alter its arm's length is designed by combining the crank-slider mechanism and *** dynamics,including the attitude and position systems,are analyzed and the former is further described as switched linear parameter varying(SLPV)systems from a control-oriented *** addition,a combined SLPV/proportion-integration-differentiation(PID)attitude controller is developed to handle different deformable quadrotor modes,which guarantees the stability of the closed-loop attitude system during the deformation process and achieves attitude ***,together with the cascade PID position controller,the entire flight controller is constructed whose feasibility is verified via fixed-point hovering and trajectory tracking experiments.

关键词： deformable quadrotor mechanics and control LPV systems switched control strategy specialized aerial system

Spectral Analysis for Preconditioning of Multi-Dimensional Riesz Fractional Diffusion Equations

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Numerical Mathematics(Theory,Methods and Applications) 2022年第3期15卷 565-591页

作者： Xin Huang Xue-Lei Lin Michael K.ng Hai-Wei sun Department of Mathematics University of MacaoMacao SARChina Shenzhen JL Computational Science and Applied Research Institute Shenzhen 518131China Beijing Computational Science Research Center Beijing 100193China Department of Mathematics The University of HongkongHong Kong SARChina

In this paper,we analyze the spectra of the preconditioned matrices arising from discretized multi-dimensional Riesz spatial fractional diffusion *** finite difference method is employed to approximate the multi-dimensional Riesz fractional derivatives,which generates symmetric positive definite ill-conditioned multi-level Toeplitz *** preconditioned conjugate gradient method with a preconditioner based on the sine transform is employed to solve the resulting linear ***,we prove that the spectra of the preconditioned matrices are uniformly bounded in the open interval(12,32)and thus the preconditioned conjugate gradient method converges linearly within an iteration number independent of the discretization ***,the proposed method can be extended to handle ill-conditioned multi-level Toeplitz matrices whose blocks are generated by functions with zeros of fractional *** theoretical results fill in a vacancy in the *** examples are presented to show the convergence performance of the proposed preconditioner that is better than other preconditioners.

关键词： Multi-dimensional Riesz fractional derivative multi-level Toeplitz matrix sine transform based preconditioner preconditioned conjugate gradient method

Hydrogen generation from ammonia electrolysis on bifunctional platinum nanocubes electrocatalysts

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Journal of Energy Chemistry 2020年第8期29卷 234-240,I0009页

作者： Hui-Ying sun Guang-Rui Xu Fu-Min Li Qi ng-Li ng Hong Pu-Jun Jin Pei Chen Yu Chen Key Laboratory of Macromolecular Science of Shaanxi Province Key Laboratory of Applied Surface and Colloid Chemistry(Ministry of Education)Shaanxi Key Laboratory for Advanced Energy DevicesSchool of Materials Science and EngineeringShaanxi Normal UniversityXi'an 710062ShaanxiChina School of Chemistry and Chemical Engineering Shaanxi Normal UniversityXi'an 710062ShaanxiChina

The ammonia electrolysis is a highly efficient and energy-saving method for ultra-pure hydrogen generation, which highly relies on electrocatalytic performance of electrocatalysts. In this work, high-quality platinum(Pt) nanocubes(Pt-NCs) with 4.5 nm size are achieved by facile hydrothermal synthesis. The physical morphology and structure of Pt-NCs are exhaustively characterized, revealing that Pt-NCs with special {100} facets have excellent uniformity, good dispersity and high crystallinity. Meanwhile, the electrocatalytic performance of Pt-NCs for ammonia electrolysis are carefully investigated in alkaline solutions, which display outstanding electroactivity and stability for both ammonia electrooxidation reaction(AEOR) and hydrogen evolution reaction(HER) in KOH solution. Furthermore, a symmetric Pt-NCs||Pt-NCs ammonia electrolyzer based on bifunctional Pt-NCs electrocatalyst is constructed, which only requires 0.68 V electrolysis voltage for hydrogen generation. Additionally, the symmetric Pt-NCs||Pt-NCs ammonia electrolyzer has excellent reversible switch capability for AEOR at anode and HER at cathode, showing outstanding alternating operation ability for ammonia electrolysis.

关键词： Ammonia electrolysis Water electrolysis Ammonia oxidation reaction Hydrogen evolution reaction Platinum nanocubes

The Transport Properties of Concrete under the Simultaneous Coupling of Fatigue Load and Environment Factors

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Journal of Wuhan University of Technology(Materials Science) 2012年第1期27卷 181-186页

作者： WAng Caihui sun Wei JIng Jinyang HAN Jiande R0ng Hui School of Materials Science and Engineering Southeast University Jiangsu Key Laboratory of Construction Materials

A set of coupling experimental instrument was designed to study the transport properties of chloride ion in concrete under simultaneous coupling action of fatigue load and environmental factors. Firstly the water-saturated performance of modem concrete was investigated, then diffusion performance of chloride ion under different stress levels and different temperature were studied respectively; meanwhile, the time- dependent behavior of the chloride ion diffusion in concrete was also researched. The results showed that the saturation degree of concrete can reach as high as 99%. Besides, diffusion coefficient of chloride ion increased with increasing of the stress level and temperature, and when the stress level and temperature are at 0.6 and 60 ℃ respectively, the diffusion coefficient is 6.3 ×10 -14 m2/s, moreover the diffusion coefficient of chloride ion in concrete decreased with time under the simultaneous coupling action of fatigue load and environment factors.

关键词： chloride diffusion fatigue load concrete stress level temperature time dependent

Tree pruning for MIMO sphere detection based on MMSE detection

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The Journal of China Universities of Posts and Telecommunications 2012年第4期19卷 64-72页

作者： WAng Shi-liang sun Song-lin J1ng Xiao-jun LU Yue-ming School of Information and Communication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China Key Laboratory of Trustworthy Distributed Computing and Service Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China

Tree pruning is an effective algorithm to reduce the complexity of sphere detection （SD） for multiple-input multiple-output （MIMO） communication systems. How to determine the tree pruning rule, as well as by what the tradeoff between the performance and the complexity can be achieved, is still an open problem. In this paper, a tree pruning algorithm is proposed based on minimum mean square error （MMSE） detection. The proposed algorithm first preforms MMSE detection since the complexity of MMSE detection is very low. Then the pruning constraints will be set according to the scaled path metrics of the MMSE solution. The choice of the scale factors and their influences on the complexity and performance are also discussed. Through analysis and simulations, it is shown that the complexity is reduced significantly with negligible performance degradation and additional computations.

关键词： MIMO sphere detection tree pruning MMSE detection

CLINICAL AND GENETIC ANALYSIS OF THREE FAMILIES WITH FAMILIAR AMYLOID POLYNEUROPATHY

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Chinese Medical Sciences Journal 2008年第4期23卷 230-233页

作者： Yan-feng Li Hou ng Iok sun U Waii Leong Department of Neurology Peking Union Medical College Hospital Chinese Academy of Medical Sciences ＆ Peking Union Medical College Beijing 100730 Internal Medicine Department Centro Hospitalar Conde de S. Januario Macao CP3001

Objective To study the clinical and genetic features of familiar amyloid polyneuropathy (FAP). Methods Three families of suspected FAP in China mainland and Macao were investigated on aspects of clinical manifestations, histological features, and gene analysis. Results All the 3 families had the clinical features of sensory and motor polyneuropathies, and notable vegetative nerve involvements. Affected cases of one family had ultrasound proved cardiomyopathy. Histological studies showed amyloid deposition in all the biopsy tissues of the affected cases of the 3 families, and anti-transthyretin antisera staining was positive in 3 cases of one family. Gene analysis confirmed that mutation types were amyloidogenic transthyretin (ATTR) Val30Met, Phe33Val, and Gly67Glu in the 3 families respectively. The ATTR Gly67Glu family had a shorter survival time due to the heart involvement compared with the other 2 families. Conclusion FAP is an autosomal dominant inherited disease, with its clinical manifestations related to the type of genetic mutation.

关键词： familiar amyloid polyneuropathy amyloidosis gene mutation

High-Resolution Infrared-Vacuum Ultraviolet Photoion and Pulsed Field Ionization-Photoelectron Methods for Spectroscopic Studies of Neutrals and Cations

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Chinese Journal of Chemical Physics 2008年第3期21卷 193-201页

作者： Xi Xing Beth Reed Mi Kyung Bahng Peng Wang Hin Koo Woo sun Jong Baek Chee Shing Lain Cheuk Yiu ng Department of Chemistry University of California Davis Davis California 95616 USA

We show that by scanning the frequency of a single mode infrared （IR） optical parametric oscillator （IR- OPO） laser to excite the molecular species of interest and fixing the frequency of a vacuum ultraviolet （VUV） laser to photoionize the IR excited species, high-resolution IR spectra of polyatomic neutrals can be obtained with high sensitivity. The fact that this IR-VUV-photoion （IR-VUV-PI） method is based on VUV photoionization probe, and thus, allows the identification of the neutral IR absorber, makes it applicable for IR spectroscopy measurements of isotopemers, radicals, and clusters, which usually exist as impure samples. The highly resolved IR-VUV-PI measurements achieved using the single mode IR-OPO laser have made possible the selection of single rovibrational states of CH3X （X=Br and I）, C2H4, and C3H4 for VUV-pulsed field ionization-photoelectron （VUV-PFI-PE） measurements, resulting in rovibrationally resolved photoelectron spectra for these polyatomic molecules. These experiments show that the signal- to-noise ratios of the IR-VUV-PI and IR-VUV-PFI-PE spectra obtained by employing the high-resolution IR-OPO laser are significantly higher than those observed in previous IR-VUV-PI and IR-VUV-PFI-PE studies using a low-resolution IR-OPO laser. Further improvement in sensitivity of IR-VUV-PI and IR- VUV-PFI-PE measurements by using the collinear arrangement of IR-VUV lasers and molecular beam is discussed.

关键词： Vacuum ultraviolet Infrared Pulse-field photoelectron High resolution

Lessons Learned from the Tragedy during the 100 km Ultramarathon Race in Baiyin,Gansu Province on 22 May 2021

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Advances in Atmospheric Sciences 2021年第11期38卷 1803-1810页

作者： Qinghong ZHAng Chan-Pang ng Kan DAI Jun XU Jian TAng Juanzhen sun Mu MU Department of Atmospheric and Oceanic Sciences School of PhysicsPeking UniversityBeijing 100871China HIWeather International Coordination Office Chinese Academy of Meteorological SciencesBeijing 100081China China Meteorological Administration Beijing 100081China National Center for Atmospheric Science BoulderCO 80307United States Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China

Twenty-one runners died of hypothermia during the 100 km Ultramarathon Mountain race in Baiyin,Gansu Province on 22 May *** hypothermia was caused by a combination of low temperatures,precipitation,and high winds associated with a typical large-scale cold front passing by the race site that *** on historical hourly records of 13 meteorological surface stations over the past six years,temperature(3.0°C)and apparent temperature(−5.1°C)at 1200 LST as well as gust wind speed(11.2 m s^(−1))at 1100 LST on the day of the tragedy were found to be within the top or bottom 5th percentile for the month of *** precipitation was only moderate at this time,but when temperature lower than 3.0°C,gust wind speed greater than 11.2 m s^(−1),and precipitation greater than 0.1 mm for any adjacent three hours were combined together,1200 LST 22 May fell within the top 0.1%of *** European Centre for Medium-range Weather Forecasting model produced reasonably good forecasts of the low temperature and high wind one day and seven days before the event,*** on this study,lessons that can be learned from this tragedy are summarized from an academic perspective:Hazard and impact forecasts of high-impact weather events should be developed to increase the value of weather *** forecasts should be issued by government weather agencies and communicated well to the *** more importantly,knowledge of how to evaluate the impact of weather should be delivered to the public in the *** would like to extend our deepest condolences to the families and loved ones of the people who lost their lives in this tragedy,including 21 runners and one *** our efforts honor those who lost their lives by highlighting the value of weather forecasting and calling for greater action in the future.

关键词： low temperature high wind precipitation value of weather forecast

Ototoxic destruction by co-administration of kanamycin and ethacrynic acid in rats

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2011年第10期12卷 853-861页

作者： Hong LIU Da-lian D1ng Hai-yan JIAng Xue-wen WU Richard SALVI Hong sun Center for Hearing and Deafness University at Buffalo State University of New York New York 14214 USA Department of Otolaryngology the Third Xiangya Hospital of Central South University Changsha 410013 China Department of Otolaryngology Xiangya Hospital of Central South University Changsha 410008 China

It is well known that ethacrynic acid (EA) can potentiate the ototoxicity of aminoglycoside antibiotics (AmAn) such as kanamycin (KM),if they were applied at the same ***,to create the model of EA-KMinduced cochlear lesion in rats,adult rats received a single injection of EA (75 mg/kg,intravenous injection),or followed immediately by KM (500 mg/kg,intramuscular injection).The hearing function was assessed by auditory brainstem response (ABR) measurement in response to click and/or tone bursts at 4,8,12,16,20,24,and 32 *** static microcirculation status in the stria vascularis after a single EA injection was evaluated with eosin *** pathological changes in cochlear and vestibular hair cells were also quantified after co-administration of EA and *** a single EA injection,blood flow in vessels supplying the stria vascularis rapidly ***,the blood supply to the cochlear lateral wall partially recovered 5 h after EA *** changes in ABR were basically parallel to the microcirculation changes in stria vascularis after single EA ***,disposable co-administration of EA and KM resulted in a permanent hearing loss and severe damage to the cochlear hair cells,but spared the vestibular hair *** the cochlear lateral wall is the important part of the blood-cochlea barrier,EA-induced anoxic damage to the epithelium of stria vascularis may enhance the entry of KM to the ***,experimental animal model of selective cochlear damage with normal vestibular systems can be reliably created through co-administration of EA and KM.

关键词： Ototoxicity Ethacrynic acid Kanamycin Rat Blood-cochlea barrier