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| 1 | Unbalance Vibratory Displacement Compensation for Active Magnetic Bearings显示文摘As the dynamic stiffness of radial magnetic bearings is not big enough,when the rotor spins at high speed,unbalance displacement vibration phenomenon will be produced.The most effective way for reducing the displacement vibration is to enhance the radial magnetic bearing stiffness through increasing the control currents,but the suitable control currents are not easy to be provided,especially,to be provided in real time.To implement real time unbalance displacement vibration compensation,through analyzing active magnetic bearings(AMB) mathematical model,the existence of radial displacement runout is demonstrated.To restrain the runout,a new control scheme-adaptive iterative learning control(AILC) is proposed in view of rotor frequency periodic uncertainties during the startup process.The previous error signal is added into AILC learning law to enhance the convergence speed,and an impacting factor influenced by the rotor rotating frequency is introduced as learning output coefficient to improve the rotor control effects.As a feed-forward compensation controller,AILC can provide one unknown and perfect compensatory signal to make the rotor rotate around its geometric axis through power amplifier and radial magnetic bearings.To improve AMB closed-loop control system robust stability,one kind of incomplete differential PID feedback controller is adopted.The correctness of the AILC algorithm is validated by the simulation of AMB mathematical model adding AILC compensation algorithm through MATLAB soft.And the compensation for fixed rotational frequency is implemented in the actual AMB system.The simulation and experiment results show that the compensation scheme based on AILC algorithm as feed-forward compensation and PID algorithm as close-loop control can realize AMB system displacement minimum compensation at one fixed frequency,and improve the stability of the control system.The proposed research provides a new adaptive iterative learning control algorithm and control strategy for AMB displacement minimum compensation,and provides some references for time-varied displacement minimum compensation. | GAO Hui XU Longxiang ZHU Yili | 2013 | Chinese Journal of Mechanical Engineering2013，26，1： | 14 |
| 2 | Heuristic Solutions of Virtual Network Embedding: A Survey显示文摘Network virtualization(NV) is considered as an enabling tool to remove the gradual ossification of current Internet. In the network virtualization environment, a set of heterogeneous virtual networks(VNs), isolated from each other, share the underlying resources of one or multiple substrate networks(SNs) according to the resource allocation strategy. This kind of resource allocation strategy is commonly known as so called Virtual Network Embedding(VNE) algorithm in network virtualization. Owing to the common sense that VNE problem is NP-hard in nature, most of VNE algorithms proposed in the literature are heuristic. This paper surveys and analyzes a number of representative heuristic solutions in the literature. Apart from the analysis of representative heuristic solutions, a taxonomy of the heuristic solutions is also presented in the form of table. Future research directions of VNE, especially for the heuristics, are emphasized and highlighted at the end of this survey. | Haotong Cao Han Hu Zhicheng Qu Longxiang Yang | 2018 | China Communications2018，15，3： | 13 |
| 3 | HIGH TEMPERATURE DISPLACEMENT SENSOR显示文摘A high temperature displacement sensor based on the principle of eddy-current is investigated. A new temperature compensation technique by using eddy-current effect is presented to satisfy the special requirement at high temperature up to 550℃. The experiment shows that the temperature compensation technique leads to good temperature stability for the sensors. The variation of the sensitivity as well as the temperature drift of the sensor with temperature compensation technique is only about 7.4% and 90~350 mV at 550℃ compared with that at room temperature, and that of the sensor without temperature compensation technique is about 31.2% and 2~3 V at 550℃ compared with that at room temperature. A new dynamic calibration method for the eddy-current displacement sensor is presented, which is very easy to be realized especially in high frequency and at high temperatures. The high temperature displacement sensors developed are successfully used at temperature up to 550℃ in a magnetic bearing system for more than 100 h. | Xu Longxiang Zhang Jinyu Schweitzer Gerhard | 2005 | Chinese Journal of Mechanical Engineering2005，18，3： | 11 |
| 4 | Real-time Feed-forward Force Compensation for Active Magnetic Bearings System Based on H∞ Controller显示文摘There are two kinds of unbalance vibrations-force vibration and displacement vibration due to the existence of unbalance excitation in active magnetic bearings(AMB) system. And two unbalance compensation methods-closed-loop feedback and open loop feed-forward are presented to reduce the force vibration. The transfer function order of the control system directly influencing the system stability will be increased when the closed-loop method is adopted, which makes the real-time compensation not easily achieved. While the open loop method would not increase the primary transfer function order, it provides conditions for real-time compensation. But the real-time compensation signals are not easy to be obtained in the open loop method. To implement real-time force compensation, a new method is proposed to reduce the force vibration caused by the rotor unbalance on the basis of AMB active control. The method realizes real-time and on-line force auto-compensation based on H∞ controller and one novel feed-forward compensation controller, which makes the rotor rotate around its inertia axis. The time-variable feed-forward compensatory signal is provided by a modified adaptive variable step-size least mean square(VSLMS) algorithm. And the relevant least mean square(LMS) algorithm parameters are used to solve the H∞ controller weighting functions. The simulation of the new method to compensate some frequency-variable and sinusoidal signals is completed by MATLAB programming, and real-time compensation is implemented in the actual AMB experimental system. The simulation and experiment results show that the compensation scheme can improve the robust stability and the anti-interference ability of the whole AMB system by using H∞ controller to achieve close-loop control, and then real-time force unbalance compensation is implemented. The proposed research provides a new control strategy containing real-time algorithm and H∞ controller for the force compensation of AMB system. And the stability of the control system is finally improved. | GAO Hui XU Longxiang | 2011 | Chinese Journal of Mechanical Engineering2011，24，1： | 11 |
| 5 | Non-Orthogonal Multiple Access in Cell-Free Massive MIMO Networks显示文摘In this paper, we investigate the downlink performance of cell-free massive multi-input multi-output non-orthogonal multiple access(CF-m MIMO-NOMA) system with conjugate beamforming precoder and compare against the orthogonal multiple access(OMA) counterpart. A novel achievable closed-form spectral efficiency(SE) expression is derived, which characterizes the effects of the channel estimation error, pilot contamination, imperfect successive interference cancellation(SIC) operation, and power optimization technique. Then, motivated by the closedform result, a sum-SE maximization algorithm with the sequential convex approximation(SCA) is proposed, subject to each AP power constraint and SIC power constraint. Numerical experiments indicate that the proposed sum-SE maximization algorithms have a fast converge rate, within about five iterations. In addition, compared with the full power control(FPC) scheme, our algorithms can significantly improve the achievable sum-SE. Moreover, NOMA outperforms OMA in many respects in the presence of the proposed algorithms. | Yao Zhang Haotong Cao Meng Zhou Longxiang Yang | 2020 | China Communications2020，17，8： | 7 |
| 6 | Classification of the Gut Microbiota of Patients in Intensive Care Units During Development of Sepsis and Septic Shock显示文摘The gut microbiota of intensive care unit(ICU)patients displays extreme dysbiosis associated with increased susceptibility to organ failure,sepsis,and septic shock.However,such dysbiosis is difficult to characterize owing to the high dimensional complexity of the gut microbiota.We tested whether the concept of enterotype can be applied to the gut microbiota of ICU patients to describe the dysbiosis.We collected 131 fecal samples from 64 ICU patients diagnosed with sepsis or septic shock and performed 16S rRNA gene sequencing to dissect their gut microbiota compositions.During the development of sepsis or septic shock and during various medical treatments,the ICU patients always exhibited two dysbiotic microbiota patterns,or ICU-enterotypes,which could not be explained by host properties such as age,sex,and body mass index,or external stressors such as infection site and antibiotic use.ICU-enterotype I(ICU E1)comprised predominantly Bacteroides and an unclassified genus of Enterobacteriaceae,while ICU-enterotype II(ICU E2)comprised predominantly Enterococcus.Among more critically ill patients with Acute Physiology and Chronic Health Evaluation II(APACHE II)scores>18,septic shock was more likely to occur with ICU E1(P=0.041).Additionally,ICU E1 was correlated with high serum lactate levels(P=0.007).Therefore,different patterns of dysbiosis were correlated with different clinical outcomes,suggesting that ICU-enterotypes should be diagnosed as independent clinical indices.Thus,the microbial-based human index classifier we propose is precise and effective for timely monitoring of ICU-enterotypes of individual patients.This work is a first step toward precision medicine for septic patients based on their gut microbiota profiles. | Wanglin Liu Mingyue Cheng Jinman Li Peng Zhang Hang Fan Qinghe Hu Maozhen Han Longxiang Su Huaiwu He Yigang Tong Kang Ning Yun Long | 2020 | Genomics, Proteomics & Bioinformatics2020，18，6： | 7 |
| 7 | Prognosis and weaning of elderly multiple organ dysfunction syndrome patients with invasive mechanical ventilation显示文摘 | Xiao Kun Su Longxiang Han Bingchao Guo Chao Feng Lin Jiang Zhaoxu Wang Huijuan Lin Yong Jia Yanhong She Danyang Xie Lixin | 2014 | Chinese Medical Journal2014，，1： | 7 |
| 8 | Smart Service System(SSS):A Novel Architecture Enabling Coordination of Heterogeneous Networking Technologies and Devices for Internet of Things显示文摘In Internet of Things(IoT), the devices or terminals are connected with each other, which can be very diverse over the wireless networks. Unfortunately, the current devices are not designed to communicate with the collocated devices which employ different communication technologies. Consequently, the communication between these devices will be realized only by using the gateway nodes. This will cause the inefficient use of wireless resources. Therefore, in this paper, a smart service system(SSS) architecture is proposed, which consists of smart service terminal(SST), and smart service network(SSN), to realize the Io T in a general environment with diverse communication networks, devices, and services. The proposed architecture has the following advantages: i) the devices in this architecture cover multiple types of terminals and sensor-actuator devices; ii) the communications network therein is a converged network, and will coordinate multiple kinds of existing and emerging networks. This converged network offers ubiquitous access for various sensors and terminals; iii) the architecture has services and applications covering all smart service areas. It also provides theadaptability to new services and applications. A SSS architecture-based smart campus system was developed and deployed. Evaluation experiments of the proposed smart campus system demonstrate the SSS's advantages over the existing counterparts, and verify the effectiveness of the proposed architecture. | yongan guo hongbo zhu longxiang yang | 2017 | China Communications2017，14，3： | 6 |
| 9 | Research on experiment and calculation of foam bursting device显示文摘This research presents experimental data on mechanical foam bursting device,based on the high speed of air fluid impinging insidethe foam bursting device,foam bubbles disrupted as a consequence of pressures changed very quickly as shear force and their impact forces.Experimental data on foam-bursting capacity have been presented.Designed device can provide effective foam bursting on collapse foam. | Hazaea Mohammed Youhong SUN Ould El HousseinYarbana Longxiang XU Al-Aswar Fahmi | 2007 | Global Geology2007，10，1： | 5 |
| 10 | Dynamic Responses of Rotor Drops onto Double-decker Catcher Bearing显示文摘In an active magnetic bearing(AMB) system,the catcher bearings(CBs) are indispensable to protect the rotor and stator in case the magnetic bearings fail.Most of the former researches associated with CBs are mainly focused on the dynamic responses of the rotor drops onto traditional single-decker catcher bearings(SDCBs).But because of the lower limited speed of SDCB,it cannot withstand the ultra high speed rotation after rotor drop.In this paper,based on the analysis of the disadvantages of SDCBs,a new type of double-decker catcher bearings(DDCBs) is proposed to enhance the CB work performance in AMB system.In order to obtain the accurate rotor movements before AMB failure,the dynamic characteristics of AMB are theoretically derived.Detailed simulation models containing rigid rotor model,contact model between rotor and inner race,DDCB force model as well as heating model after rotor drop are established.Then,using those established models the dynamic responses of rotor drops onto DDCBs and SDCBs are respectively simulated.The rotor orbits,contact forces,spin speeds of various parts and heat energies after AMB failure are mainly analyzed.The simulation results show that DDCBs can effectively improve the CBs limit rotational speed and reduce the following vibrations,impacts and heating.Finally,rotor drop experiments choosing different types of CBs are carried out on the established AMB test bench.Rotor orbits,inner race temperatures as well as the rotating speeds of both inner race and intermediate races after rotor drop are synchronously measured.The experiment results verify the advantages of DDCB and the correctness of theoretical analysis.The studies provide certain theoretical and experimental references for the application of DDCBs in AMB system. | ZHU Yili JIN Chaowu XU Longxiang | 2013 | Chinese Journal of Mechanical Engineering2013，26，1： | 5 |
| 11 | On the atmospheric movement and the imbalance of observed and calculated energy in the surface layer显示文摘Based on existing researches,here we theoretically summarized the characteristics of the atmospheric movement and turbulent transport of energy and substance in the surface layer as well as the ideal and the actual models for the turbulent transport.Then,using the data observed with eddy covariance at the semiarid climate and environment monitoring station(SACOL) in Lanzhou University from May to October during four consecutive years(September 2006-August 2010),we conducted a detailed analysis of the turbulent transport in the surface layer,through introducing the relative vertical turbulence intensity to characterize the turbulence strength,RIw=wn(wn+U),and also by adopting the method for controlling data quality at different levels.Our conclusions are:(1) The turbulent transport of energy and substance in the surface layer must obey the law of conservation of energy and the law of conservation of matter,the observed and calculated energy in the surface layer must be balanced,or closed in theory,but the actual observed and calculated energy just approximates the ideal in some degree and is difficult to achieve the energy balance.(2) The energy closure rate depends much on the atmospheric state in the surface layer,and the energy closure rate increases generally with the relative vertical turbulence intensity.(3) By the way of controlling data quality at different levels,it is found that the degree of data quality control can affect the closure rate,but it does not change the fact that the energy closure rate depends on the atmospheric state.(4) The calculation method of surface soil heat flux can affect energy closure rate,but does not change its dependence on the atmospheric state. | ZUO HongChao XIAO Xia YANG QiDong DONG LongXiang CHEN JiWei WANG ShuJin | 2012 | Science China Earth Sciences2012，55，9： | 5 |
| 12 | A Survey of Embedding Algorithm for Virtual Network Embedding显示文摘Network virtualization(NV) is pushed forward by its proponents as a crucial attribute of next generation network, aiming at overcoming the gradual ossification of current networks, particularly to the worldwide Internet. Through virtualization, multiple customized virtual networks(VNs), requested by users, are allowed to coexist on the underlying substrate networks(SNs). In addition, the virtualization scheme contributes to sharing underlying physical resources simultaneously and seamlessly. However, multiple technical issues still stand in the way of NV successful implementation. One key technical issue is virtual network embedding(VNE), known as the resource allocation problem for NV. This paper conducts a survey of embedding algorithms for VNE problem. At first, the NV business model for VNE problem is presented. Then, the latest VNE problem description is presented. Main performance metrics for evaluating embedding algorithms are also involved. Afterwards, existing VNE algorithms are detailed, according to the novel proposed category approach. Next, key future research aspects of embedding algorithms are listed out. Finally, the paper is briefly concluded. | Haotong Cao Shengchen Wu Yue Hu Yun Liu Longxiang Yang | 2019 | China Communications2019，16，12： | 5 |
| 13 | Quality metrics and outcomes among critically ill patients in China:results of the national clinical quality control indicators for critical care medicine survey 2015-2019显示文摘Background:It is crucial to improve the quality of care provided to ICU patient,therefore a national survey of the medical quality of intensive care units(ICUs)was conducted to analyze adherence to quality metrics and outcomes among critically ill patients in China from 2015 to 2019.Methods:This was an ICU-level study based on a 15-indicator online survey conducted in China.Considering that ICU care quality may vary between secondary and tertiary hospitals,direct standardization was adopted to compare the rates of ICU quality indicators among provinces/regions.Multivariate analysis was performed to identify potential factors for in-hospital mortality and factors related to ventilator-associated pneumonia(VAP),catheter-related bloodstream infections(CRBSIs),and catheter-associated urinary tract infections(CAUTIs).Results:From the survey,the proportions of structural indicators were 1.83%for the number of ICU inpatients relative to the total number of inpatients,1.44%for ICU bed occupancy relative to the total inpatient bed occupancy,and 51.08%for inpatients with Acute Physiology and Chronic Health Evaluation II scores≥15.The proportions of procedural indicators were 74.37%and 76.60%for 3-hour and 6-hour surviving sepsis campaign bundle compliance,respectively,62.93%for microbiology detection,58.24%for deep vein thrombosis prophylaxis,1.49%for unplanned endotracheal extubations,1.99%for extubated inpatients reintubated within 48 hours,6.38%for unplanned transfer to the ICU,and 1.20%for 48-hour ICU readmission.The proportions of outcome indicators were 1.28‰for VAP,3.06‰for CRBSI,3.65‰for CAUTI,and 10.19%for in-hospital mortality.Although the indicators varied greatly across provinces and regions,the treatment level of ICUs in China has been stable and improved based on various quality control indicators in the past 5 years.The overall mortality rate has dropped from 10.19%to approximately 8%.Conclusions:The quality indicators of medical care in China’s ICUs are heterogeneous,which is reflected in geographic disparities and grades of hospitals.This study is of great significance for improving the homogeneity of ICUs in China. | Xi Rui Fen Dong Xudong Ma Longxiang Su Guangliang Shan Yanhong Guo Yun Long Dawei Liu Xiang Zhou | 2022 | Chinese Medical Journal2022，，9： | 4 |
| 14 | Heliox as a driving gas to atomize inhaled drugs on acute exacerbation of chronic obstructive pulmonary disease: a prospective clinical study显示文摘 | Xiao Yongjiu Su Longxiang Han Bingchao Zhang Xin Xie Lixin | 2014 | Chinese Medical Journal2014，，1： | 4 |
| 15 | Service-Oriented Network Virtualization Architecture for Internet of Things显示文摘As a key technology to realize smart services of Internet of Things(Io T),network virtualization technology can support the network diversification and ubiquity,and improve the utilization rate of network resources.This paper studies the service-oriented network virtualization architecture for Io T services.Firstly the semantic description method for Io T services is proposed,then the resource representation model and resource management model in the environment of network virtualization are presented.Based on the above models,the service-oriented virtual network architecture for Io T is established.Finally,a smart campus system is designed and deployed based on the service-oriented virtual network architecture.Moreover,the proposed architecture and models are verified in experiments. | Yongan Guo Hongbo Zhu Longxiang Yang | 2016 | China Communications2016，13，9： | 4 |
| 16 | Elastic Scattering of 7Be on Pb Target显示文摘 | Yang Yanyun Wang Jiansong Wang Qi Huang Meirong Ma Junbing Ma Peng Cao Xiguang Han Jianlong Bai Zhen Jin Shilong Hu Qiang Jin Lei Chen Jiangbo Zhang Xueying Chen Ruofu Hu Zhengguo Xu Shiwei Zhen Chuan Xu Zhiguo Xu Hushan Duan Liming Sun Zhiyu Chen Zhiqiang He Jianjun Li Songlin Lei Xiangguo Fu Fen Zhang Xueheng Yuan Xiaohua Du Chengming Yan Xinshuang Hu Jun Tang Shuwen Ye Ruiping Yang Kun Shi Fudong Zhang Wei Chen Ze Li Long Xu Xing Liu Longxiang Zhang Liyong Lin Qingyun Gou Boxing Xu Ge Zhou Xionghong Zhang Yuhu Xiao Guoqing | 2011 | IMP & HIRFL Annual Report2011，，1： | 4 |
| 17 | Power Optimization in Cell-Free Massive MIMO with Non-ideal Hardware Transceiver显示文摘A downlink cell-free massive Multipleinput multiple-output(mMIMO)system is explored.To inves tigate the impac t of hardware dis tortion on downlink cell-free mMIMO,this paper recalls a well-established model of hardware impairment and derives a new closedform downlink per-user Spectral efficiency(SE)expression for distributed conjugate beamforming precoding.Based on this trackable expression,two power control algorithms,namely max-total-SE and mixed Qualiof-service(QoS)algorithms,are proposed.Numerical results indicate that the downlink per-user SE is primarily limited by the hardware quality of the receiver,especially when the user corresponds to the receiver.In addition,the proposed max-total-SE algorithm has a fast convergence rate and can significantly improve the total SE compared to the Equal power control(EPC)scheme.Whafs more,our mixed QoS algorithm also performs well in many respects. | ZHANG Yao CAO Haotong ZHOU Meng LI Long YANG Longxiang | 2020 | Chinese Journal of Electronics2020，29，1： | 3 |
| 18 | Challenges and strategies in high-accuracy manufacturing of the world’s largest SiC aspheric mirror显示文摘In the process of manufacturing the world’s largest silicon carbide(SiC)aspheric mirror,the primary difficulties are mirror blank preparation,asphere fabrication,and testing,as well as cladding and coating.Specifically,the challenges include the homogeneity of the complicated structure casting,accuracy and efficiency of the fabrication process,print-through effect,fidelity and precision of test procedure,stress and denseness of cladding process,the dynamic range of interferometric measurement,and air turbulence error due to the long optical path.To break through such a barrier of difficulties,we proposed the water-soluble room temperature vanishing mold and gel casting technology,homogeneous microstructure reaction-formed joint technology,nano-accuracy efficient compound fabrication,gravity unloading technology,high-denseness low-defect physical vapor deposition(PVD)Si-cladding technology,test data fusion method,and time-domain averaging method,etc.Based on the proposed technologies and methods,we have accomplished the world’s largest SiC aspheric mirror with a size of φ4.03 m.The impressive performance of the SiC aspheric mirror is validated by the characteristics of the fabricated SiC aspheric mirror.The aerial density of the SiC blank is less than 120 kg/m^(2),surface shape test accuracy is better than 6 nm RMS,thickness inhomogeneity of the cladding layer is less than 5%,and the final surface figure error and roughness are 15.2 nm RMS and 0.8 nm RMS,respectively. | Xuejun Zhang Haixiang Hu Xiaokun Wang Xiao Luo Ge Zhang Wenxing Zhao Xiaoyi Wang Zhenyu Liu Ling Xiong Erhui Qi Congcong Cui Yanchao Wang Yingjie Li Xu Wang Longxiang Li Yang Bai Qiang Cheng Zhiyu Zhang Ruigang Li Wa Tang Xuefeng Zeng Weijie Deng Feng Zhang | 2022 | Light(Science & Applications)2022，11，12： | 3 |
| 19 | Exact Solutions of VNE: A Survey显示文摘Network virtualization is an enabling technology of running multiple virtual networks on a shared substrate network. It aims to deal with the ossification of current network architecture. As a crucial component of network virtualization, virtual network embedding(VNE) can efficiently and effectively allocates the substrate resource to proposed virtual network requests. According to the optimization strategy, VNE approaches can be classified into three categories: exact, heuristic and meta-heuristic solution. The VNE exact solution is the foundation of its corresponding heuristic and meta-heuristic solutions. This paper presents a survey of existing typical VNE exact solutions, and open problems for the future research of VNE exact solutions are proposed. | Haotong Cao Longxiang Yang Zeyuan Liu Mengting Wu | 2016 | China Communications2016，13，6： | 3 |
| 20 | Node Ranking Strategy in Virtual Network Embedding: An Overview显示文摘Network virtualization(NV)is a highprofile way to solve the ossification problem of the nowadays Internet,and be able to support the diversified network naturally.In NV,Virtual Network Embedding(VNE)problem has been widely considered as a crucial issue,which is aimed to embed Virtual Networks(VNs)onto the shared substrate networks(SNs)efficiently.Recently,some VNE approaches have developed Node Ranking strategies to drive and enhance the embedding efficiency.Node Ranking Strategy rank/sort the nodes according to the attributes of the node,including both residual local attributes(CPU,Bandwidth,storage,Etc.)and the global topology attributes(Number of neighborhood Nodes,Delay to other nodes,Etc.).This paper presents an overview of Node Ranking Strategies in Virtual Network Embedding,and possible directions of VNE Node Ranking Strategy. | Shengchen Wu Hao Yin Haotong Cao Longxiang Yang Hongbo Zhu | 2021 | China Communications2021，18，6： | 3 |
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