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Design for aircraft engine multi-objective controllers with switching characteristics

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Chinese Journal of Aeronautics 2014年第5期27卷 1097-1110页

作者： Liu Xiaofeng Shi Jing qi Yiwen Yuan ye School of Transportation Science and Engineering Beihang University School of Automation Shenyang Aerospace University School of Energy and Power Engineering Beihang University

The aircraft engine multi-loop control system is described and the switching control theory is introduced to solve the regulating and protecting control problems in this paper. The aircraft engine multi-loop control system is firstly described and the control problems are formulated. Secondly, the theory of the smooth switching control is devoted and a new extended scheme for the smooth switching of a switched control system is introduced. Then, for the key technologies of aero-engines switching control, a design algorithm is presented which can determine which candidate controller should be put in feedback with the plant to achieve a desired performance and the procedure to design the aircraft engine multi-loop control system is detailed. The switching performance objectives and the switching scheme are given and a family of PID controllers and compensators is designed. The simulation shows that using the switching control design method can not only improve the dynamic performance of the aircraft engine control system and reduce the switching times, but also guarantee the stability in some peculiar occasions.

关键词： Aircraft engine Compensatory controller Min/Max switching Multi-objectives control Smooth switching Switching scheme

MicroRNAs in colorectal cancer as markers and targets:Recent advances

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World Journal of Gastroenterology 2014年第15期20卷 4288-4299页

作者： Jing-Jia ye Jiang cao Clinical Research Center The Second Affiliated HospitalZhejiang University School of Medicine

MicroRNAs are evolutionarily conserved small noncoding RNA molecules encoded by eukaryotic genomic DNA,and function in post-transcriptional regulation of gene expression via base-pairing with complementary sequences in target mRNAs,resulting in translational repression or degradation of target *** represent one of the major types of epigenetic modification and play important roles in all aspects of cellular *** expression of microRNAs has been found in various human diseases including *** efforts have been made to discover the characteristic microRNA expression profiles,to understand the roles of aberrantly expressed microRNAs and underlying mechanisms in different *** the application of DNA microarray,real-time quantitative polymerase chain reaction and other molecular biology techniques,increasing evidence has been accumulated which reveal that aberrant microRNAs can be detected not only intracellularly within the cancer cells,but also extracellularly in plasma of patients,postulating the potential of aberrant microRNAs as promising diagnostic/prognostic markers and attracting therapeutic *** review is intended to provide the most recent advances in microRNA studies in one of the most common cancers,colorectal cancer,especially the identification of those specifically altered microRNAs in colorectal cancer,validation for their relevance to clinical pathological parameters of patients,functional analyses and potential applications of these microRNAs.

关键词： MicroRNA Epigenetic modification Colorectal cancer Marker Therapy

Empirical mode decomposition using variable filtering with time scale calibrating

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Journal of Systems Engineering and Electronics 2008年第6期19卷 1076-1081页

作者： Yuan ye Mei Wenbo Wu Siliang Yuan qi School of Information Science and Technology Beijing Inst. of Technology Beijing 100081 P. R. China School of Industrial Design and Information Engineering Beijing Inst. of Clothing Technology Beijing 100029 P. R. China The Science and Technology Committee of China Aerospace Science and Industry Corporation Beijing 100854 P. R. China

A novel and efficient method for decomposing a signal into a set of intrinsic mode functions （IMFs） and a trend is proposed. Unlike the original empirical mode decomposition （EMD）, which uses spline fits to extract variations from the signal by separating the local mean from the fluctuations in the decomposing process, this new method being proposed takes advantage of the theory of variable finite impulse response （FIR） filtering where filter coefficients and breakpoint frequencies can be adjusted to track any peak-to-peak time scale changes. The IMFs are results of a multiple variable frequency response FIR filtering when signals pass through the filters. Numerical examples validate that in contrast with the original EMD, the proposed method can fine-tune the frequency resolution and suppress the aliasing effectively.

关键词： empirical mode decomposition variable FIR filtering time scale calibrating.

Carrier fringe method of moire interferometry for tiny strain measurements in micro-field

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Acta Mechanica Sinica 2009年第1期25卷 101-106页

作者： Yudong cao Shibin Wang Shuangxi qi Jingwei Tong Institute of Fluid Physics.China Academy of Engineering Physics 621900 Mianyang. China Institute of Mechanics Engineering.Tianjin University 300072 Tianjin China

In this paper, we demonstrate a new optical method for tiny strain measurements based on the principle of carrier fringes of moire interferometry. A cross-line grating with frequency of 1200 lp/mm is replicated on the specimen surface, and the strain can be deduced from the changes in carrier fringes before and after the deformation of an object. Four coherent laser beams are used to obtain the carrier fringe patterns of field U and V. Both theoretical analysis and numerical simulation indicate that the ideal accuracy of strain can be controlled within a range of ±1με. Case study of a plane extension experiment shows that the measurement accuracy of strain can be controlled within the range of ±10με. The average strain values of every row of field U and every column of field V can be obtained by using this method, and approximated strain of every pixel in the whole-field can be further acquired, and thus it is possible to measure tiny strains occurred in a micro-field. The technology in this paper can provide comprehensive information for analyzing related mechanical content in the field of MEMS.

关键词： Moire interferometry - Carrier fringe Micro-field Tiny strain. Measured accuracy

Research on influence of typical microstructure characteristics of Ni base single crystal on creep rupture and deformation analysis of turbo blade

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航空动力学报 2011年第5期26卷 1148-1158页

作者： cao Juan WANG Yan-rong SHI Duo-qi School of Jet Propulsion Beijing University of Aeronautics and Astronautics Beijing 100191 China

Considering the influence of typical microstructure characteristics on creep performance,a series of UM-F single crystal alloys which had similar element components but different microstructures were used to analyze the relationship between creep life and microstructure characteristics of Ni base single *** main factors were proposed:misfit,volume fraction of precipitate and maximum matrix channel *** Microstate parameter Ymicro was established to estimate the deformation state of the *** linear relationship between the initial value of microstate parameter Y0 and creep life under a certain temperature/load was *** analyzing the high temperature region of turbo blade using the material parameters of DD 3,the creep deformation and the life prediction of the critical points of blade were obtained and the result closed to the test.

关键词：《航空动力学报》期刊摘要编辑部

Graphene-wrapped multiloculated nickel ferrite:A highly efficient electromagnetic attenuation material for microwave absorbing and green shielding

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Nano Research 2022年第7期15卷 6751-6760页

作者： Yuchang Wang Lihua Yao qi Zheng Mao-Sheng cao School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China School of Mechatronical Engineering Shanxi Datong UniversityDatong 037003China

Dedicating to the exploration of efficient electromagnetic(EM)absorption and electromagnetic interference(EMI)shielding materials is the main strategy to solve the EM radiation *** development of multifunction EM attenuation materials that are compatible together EM absorption and EMI shielding properties is deserved our exploration and ***,the graphenewrapped multiloculated NiFe_(2)O_(4) composites are reported as multifunction EM absorbing and EMI shielding *** conductive networks configurated by the overlapping flexible graphene promote the riched polarization genes,as well as electron transmission paths,and thus optimize the dielectric constant of the ***,the introduction of magnetic NiFe_(2)O_(4) further establishes the magnetic-dielectric synergy *** abundant non-homogeneous interfaces not only generate effective interfacial polarization,also the deliberate multiloculated structure of NiFe_(2)O_(4) strengthens multi-scattering and multi-reflection sites to expand the transmission path of EM *** it turns out,the best impedance matching is matched at a lower filled concentration to achieve the strongest reflection loss value of−48.1 ***,green EMI shielding based on a predominantly EM absorption and dissipation is achieved by an enlargement of the filled concentration,which is helpful to reduce the secondary EM wave reflection pollution to the *** addition,the electrocatalytic properties are further *** graphene-wrapped multiloculated NiFe_(2)O_(4) shows the well electrocatalytic activity as electrocatalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER),which is mainly attributed to the interconnected structures formed by graphene and NiFe_(2)O_(4) *** structural advantages of multiloculated NiFe_(2)O_(4) expose more active sites,which plays an important role in optimizing catalytic *** work provides an excellent jumping-off point

关键词： electromagnetic absorbing green electromagnetic shielding multifunction electromagnetic attenuation material graphenewrapped multiloculated Fe_(2)O_(4) oxygen evolution reaction hydrogen evolution reaction

3D MXene architectures as sulfur hosts for high-performance lithium-sulfur batteries

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Journal of Energy Chemistry 2022年第3期31卷 429-439,I0012页

作者： Yu-Hong Liu cao-Yu Wang Si-Lin Yang Fei-Fei cao Huan ye College of Science Huazhong Agricultural UniversityWuhan 430070HubeiChina

Lithium-sulfur batteries(LSBs)are one of the most promising energy storage devices because of their high theoretical energy density;however,inherent issues including poor electrical conductivity and severe dissolution of S and its discharged products hinder their practical *** have metallic conductivity,ultra-thin two-dimensional(2D)structures,rich surface functional groups,and macrostructural adjustability and have been widely used to design advanced sulfur hosts.3D network structures assembled by 2D MXene nanosheets have shown superior performance for improving reaction kinetics,accommodating and dispersing sulfur at the micro-/nanoscale,and capturing polysulfides due to their porous interconnected ***,the applications of MXene architectures related to 2D layered structures,3D multilayered structures,and 3D spherical structures as sulfur hosts are *** structure-performance relationship,challenges for current designs,and opportunities for future 3D architectures for LSBs are also analyzed.

关键词： Lithium-sulfur batteries Cathodes Sulfur hosts MXenes 3D architectures

Donor-derived infections among Chinese donation after cardiac death liver recipients

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World Journal of Gastroenterology 2017年第31期23卷 5809-5816页

作者： qi-Fa ye Wei Zhou qi-Quan Wan Department of Transplant Surgery the Third Xiangya Hospital of Central South University Department of Transplant Surgery Zhongnan Hospital of Wuhan University

AIM To investigate blood cultures of deceased donors and report the confirmed transmission of bacterial infection from donors to liver *** We retrospectively studied the results of blood cultures among our donation after cardiac death(DCD) donors and calculated the donor-derived bacterial infection rates among liver recipients. Study participants underwent liver transplantation between January 1, 2010 and February 1, 2017. The study involved a total of 67 recipients of liver grafts from 67 DCD donors. We extracted the data of donors' and patients' characteristics, culture results and clinical outcomes, especially the post-transplant complications in liver recipients, from electronic medical records. We analyzed the characteristics of the donors and the corresponding liver recipients with emphasis put on donor-derived *** Head trauma was the most common origin of death among our 67 DCD donors(46.3%). Blood taken prior to the procurement operation was cultured for 53 of the donors, with 17 episodes of bloodstream infections developing from 13 donors. The predominant organism isolated from the blood of donors was Gram-positive bacteria(70.6%). Only three(4.5%) of 67 liver recipients developed confirmed donor-derived bacterial infections,with two isolates of multidrug-resistant Klebsiella pneumoniae and one isolate of multidrug-resistant Enterobacter aerogenes. The liver recipients with donorderived infections showed relation to higher crude mortality and graft loss rates(33.3% each) within 3 mo post transplantation, as compared to those without donor-derived infections(9.4% and 4.7%, respectively). All three liver recipients received appropriate antimicrobial *** Liver recipients have high occurrence of donor-derived infections. The liver recipients with donor-derived multidrug-resistant Enterobacteriaceae infections can have good outcome if appropriate antimicrobial therapy is given.

关键词： Liver transplant Donation after cardiac death donor Infection Multidrug resistant Bacteria Transmission

High Pressure Treatment Changes Spoilage Characteristics and Shelf Life of Pacific Oysters(Crassostrea gigas)During Refrigerated Storage

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Journal of Ocean University of China 2017年第2期16卷 351-355页

作者： cao Rong ZHAO Ling LIU qi Department of Food Engineering and Nutrition Yellow Sea Fisheries Research InstituteChinese Academy of Fishery SciencesQingdao 266071P.R.China

The effects of high pressure(HP) treatment on spoilage characteristic and shelf life extension of Pacific oysters(Crassostrea gigas) during refrigerated storage were *** showed that HP treatment of 275 MPa for 3 min or 300 MPa for 2 min could achieve 100% full release of oyster adductor muscle,pressures higher than 350 MPa caused excessive release as the shells of oysters were broken,thus use of higher pressures should be cautious in oyster processing industry because of its adverse impact on the appearance of *** treatment(300 MPa,2 min) was proper for the shucking of Pacific oyster(Crassostrea gigas) in *** treatment caused no organoleptic ***,HP treatment resulted in obvious differences in biochemical spoilage indicators(p H,TVB-N and TBARS) changes and volatile compounds profile determined by electronic nose during *** treatment(300 MPa,2 min) also led to a reduction of aerobic bacterial count(APC) by 1.27 log ***,the APC values of oysters treated by HP were always lower than those of the control samples during *** on the organoleptic,biochemical and microbiological indicators,shelf life of 6-8 d for control and 12 d for HP-treated oysters could be *** treatment showed great potential in oyster processing and preservation.

关键词： high pressure processing oyster spoilage E-nose shelf life