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Orbit Design Elements of Chang’e 5 Mission

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Space(Science & Technology) 2021年第1期2021卷 28-49页

作者： Zhong-Sheng Wang Zhanfeng meng Shan gao Jing Peng Beijing Institute of Spacecraft System Engineering Beijing 100094China

The three key orbit design technologies employed in the Chang’e 5 mission are identified and discussed in this paper:orbit design for lunar orbit rendezvous and docking,orbit design for precision lunar landing and inclination optimization,and orbit design for Moon-to-Earth ***,an overview of the Chang’e 5 mission profile is presented,which is followed by detailed discussions of the three key orbit design technologies,including an introduction of the tracking-based orbit design *** data are provided to demonstrate the correctness of the designs.

关键词： discussions orbit Earth

Selective Oxidation of PM over Li Doped Potassium Titanate Catalysts

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China Petroleum Processing & Petrochemical Technology 2012年第2期14卷 50-54页

作者： meng Xiuhong gao Yuan Wang Qiang Duan Linhai Key Laboratory of Petrochemical Catalytic Science and Technology Liaoning Shihua University Fushun113001 P. R. China Department of Chemistry University of Oxford Oxford OX1 3TA United Kingdom)

K2Ti2O5 and LixK2-xTi2O5 samples with varying K contents （x=0.125, 0.15, 0.3）, targeted on removal of two main environmental pollutants： PM and NOx, were synthesized by the solid state method using TiO2, KNO3 and LiOH-H2O as starting materials and were characterized by X-ray diffractometry, scanning electron microscopy, and BET. The catalytic activity of titanate catalysts on PM oxidation was evaluated using the temperature programmed oxidation （TPO） method. The test results showed that the perovskite structure of K2Ti205 was still retained after doping a small amount of Li, and the catalytic performance of LixK2-xTi2O5 had been improved significantly compared with that of K2Ti2O5. Li0.15K1.85Ti205 catalyst had the highest catalytic activity with an ignition temperature of 210℃ and a peak temperature of 290℃. The catalytic activity of both K2Ti2O5 and LixK2-xTi2O5 under intimate contact was higher than that under loose contact. When the exhaust gas flow rate was around 100 mL/min, the catalyst samples showed a highest activity. The Li doped K2Ti2O5 could be an excellent candidate for PM oxidation due to its high oxidation activity, water stability, resistance to sulfur poisoning and economical advantages.

关键词： potassium titanates diesel PM PM oxidation Li doping

Discrete Global Optimization Problems with a Modified Discrete Filled Function

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Journal of the Operations Research Society of China 2015年第3期3卷 297-315页

作者： Yong-Jian Yang meng-Li He Yue-Lin gao Department of Mathematics Shanghai UniversityShanghai 200444China Institute of Information and System Science Beifang University for NationalitiesYinchuan 750021China

This paper considers discrete global optimization *** traditional definition of the discrete filled function is modified in this *** on the modified definition,a new discrete filled function is presented and an algorithm for discrete global optimization is developed from the discrete filled *** experiments reported in this paper on several test problems with up to 200 variables have demonstrated the efficiency of the algorithm.

关键词： Filled function method Discrete global optimization Nonlinear integer programming

POLY(MALEIC ANHYDRIDE-CO-ACRYLIC ACID)/POLY(ETHYLENE GLYCOL)HYDROGELS WITH pH- AND IONIC-STRENGTH-RESPONSES

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Chinese Journal of Polymer Science 2010年第6期28卷 951-959页

作者： meng Yang Bo-tian Liu Ge gao Xiao-li Liu Feng-qi Liu College of Chemistry and Macdiarmid Laboratory Jilin University Changchun 130012 China

Poly（maleic anhydride-coacrylic acid）,P（MA-AA）,was synthesized by the free-radical copolymerization of maleic anhydride with acrylic acid,and fast responsive pH-sensitive poly（maleic anhydride-co-acrylic acid）/polyethylene glycol,P（MA-AA）/PEG,hydrogels were prepared using PEG as macromolecular cross-linking ***-IR and ~1H-NMR spectrometry were applied to characterize the structure of P（MA-AA）.The influences of pH and ionic strength on the swelling behavior of P（MA-AA）/PEG hydrogels and the swelling-deswelling changes along with the repeated changes between acid and alkali conditions were *** results showed that there was a hundredfold difference in the swelling ratios between the conditions of acid and alkali,and the swelling capability could not be weakened after multiple swelling-deswelling *** results of swelling kinetics demonstrated that the response rate of P（MA-AA）/PEG hydrogels was very fast,because the swelling transition points always occurred at 10 *** pH-responsive hydrogels reported here might be a smart material for potentially applications in many areas,including biosensors,drug-delivery devices and tissue engineering.

关键词： pH-response P(MA-AA) Macromolecular cross-linking agent External cross-linking

Approaching the uniaxiality of magnetic anisotropy in singlemolecule magnets

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Science China Chemistry 2023年第3期66卷 683-702页

作者： Chen Wang Yin-Shan meng Shang-Da Jiang Bing-Wu Wang Song gao School of Chemistry Chemical Engineering and Life ScienceWuhan University of TechnologyWuhan 430070China Beijing National Laboratory of Molecular Science Beijing Key Laboratory for Magnetoeletric Materials and DevicesCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China State Key Laboratory of Fine Chemicals Dalian University of TechnologyDalian 116024China Spin-X Institute School of Chemistry and Chemical EngineeringState Key Laboratory of Luminescent Materials and DevicesGuangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional MaterialsSouth China University of TechnologyGuangzhou 510641China

Single-molecule magnets(SMMs),which can exhibit slow magnetization relaxation and bulk-magnet-like hysteresis of purely molecular origin,are promising candidates for high-density information storage,molecular spintronics,and quantum *** realize their applications,it is crucial to improve the blocking temperature(TB)and the effective relaxation barrier(Ueff).Three decades of multidisciplinary research have yielded distinct SMMs with a state-of-the-art Ueff of up to 2,000 K and a TB of up to the liquid nitrogen *** strategies have been investigated and summarized,which revealed that enhancing the uniaxiality of magnetic anisotropy is critical for constructing high-performance ***,magnetic anisotropy,a key property that connects the molecular structure symmetry and performance of SMMs,plays a fundamental role in dictating magneto-structural *** and employing magnetic anisotropy would be significantly beneficial for rationally designing high-performance *** review focuses on the magnetic anisotropy of *** illustrate the origin and manifestation of magnetic anisotropy in mononuclear 3d-and 4f-block metal *** then introduce developed approaches to investigate magnetic anisotropy both theoretically and *** SMMs by optimizing uniaxial magnetic anisotropy through lanthanide metallocene,symmetry controlling,and low-coordination approaches are ***,the remaining challenges and opportunities in this field will be discussed.

关键词： single-molecule magnets magnetic anisotropy uniaxiality lanthanide

Preparation of isotropic Sm_(2)Fe_(17)N_(x) magnetic powders and their bonded magnets

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Rare Metals 2006年第Z1期25卷 568-571页

作者： YE Jinwen LIU Ying LI meng SONG Dayu gao Shengji TU Mingjing College of Material Science and Engineering Sichuan UniversityChengdu 610065China

The isotropic Sm_(2)Fe_(17)N_(x)magnetic powders were prepared by Hydrogenation-Disproportion-Desorption-Recombination(HDDR)*** phase and microstructure evolutionary process of Sm-Fe alloy during the solidification,homogenization,HDDR and nitration processes were investigated by means of XRD,SEM,EDX and *** results show that the homogeneous Sm_(2)Fe_(17)alloy was successfully obtained and the impurity phases and residual stress were well removed by heated at 1050℃for 24 *** heated at 800℃for 1h in H_(2)of 0.1 MPa,the alloy turns into SmHx andα-Fe with plenty of *** vacuumized at 800℃for 2 h the alloy recombines into Sm_(2)Fe_(17)with a crystal grain size of about 85 *** lattice constant of the alloy increases and the expanding of the crystal cell reaches 6.28%after nitrified at 500℃for 5 *** magnetic property of isotropic bonded Sm_(2)Fe_(17)N_(x)magnets is B_(r)=0.6704 T,H_(cj)=1015 kA·m^(-1),(BH)_(max)=73.7 kJ·m^(-3)with a density of 6.04 g·cm^(-3).

关键词： rare earths permanent magnets SmFeN

Dynamic spectrum allocation for cell range extension in tiered Macro-Pico heterogeneous networks

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The Journal of China Universities of Posts and Telecommunications 2013年第1期20卷 66-72页

作者： TIAN Peng TIAN Hui gao Li-qi ZHANG Jun WANG meng School of Information and Communication Engineering Beijing University of Posts and Telecommunications

Heterogeneous networks are employed in the next generation communication systems to enhance the area spectral efficiency （ASE）, where cell range extension （CRE） is a promising technique to improve the cell edge performance and utilize the low power node （LPN） resources more effectively. In this paper we propose a dynamic spectrum aUocation scheme for Macro-Pico scenario to mitigate both the co-tier and cross-tier interferences. The available system spectrum is divided into different parts by four steps, i.e. user set partition, service request collection, cross-tier occupation and CRE occupation decision, while the service request of each user is taken into consideration. During the process implementation, the reference signal receiving power （RSRP） threshold is derived by mathematical means to judge cell edge macro users when a predefined ratio is given. Simulation results show that the proposed scheme reaches almost the same cell edge performance with the best existing option, meanwhile provides higher overall system throughput and better spectral efficiency. Therefore, much better balance is achieved.

关键词： spectrum allocation heterogeneous network elCIC range extension pico cells

Highly Red Emissive Conjugated Homopolymers Based on Double B←N Bridged Bipyridine Unit

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Chinese Journal of Polymer Science 2024年第8期42卷 1029-1037页

作者： Yu-Yue gao Kai-Yuan Zhang Shu-meng Wang Hui Tong Jun Liu State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei 230026China

Conjugated homopolymers based on six-member rings,e.g.,polyfluorene,always exhibit blue emission and conjugated homopolymers based on five-member rings,e.g.,polythiophene,can give red emission with low *** this work,we report a series of new conjugated homopolymers based on six-member rings with high-efficiency deep-red *** repeating units of the red light emitting homopolymers are double B←N bridged bipyridine(BNBP)with the boron atoms functionalized with diphenyl,borafluorene,and 2,7-di-tert-butyl-borafluorene groups,*** relationship between the chemical structures and the opto-electronic properties of the monomers and the homopolymers has been systematically *** three polymers emit pure red light(λ_(max)=656 nm)or deep red light(λ_(max)=693 nm)with fluorescence quantum efficiency in solution higher than 60%.The polymers can be used as the emitters in solution-processed organic light-emitting diodes with red emission and decent device *** work indicates a new strategy to design highly efficient light emitting conjugated polymers.

关键词： Conjugated homopolymers Double B←N bridged bipyridine(BNBP) Deep-red emission High fluorescent efficiency

Establishment and Modification of Ninety-seven Pneumococcal Serotyping Assays Based on Quantitative Real-time Polymerase Chain Reaction

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Biomedical and Environmental Sciences 2023年第9期36卷 787-799页

作者： CHE Jie CHEN Bo Han XU Li gao Yuan YUE meng meng CHEN Zi Man ZHANG Mao Jun SHAO Zhu Jun National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases National Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijing 102206China School of Public Health Nanjing Medical UniversityNanjing 210029Jiangsu China

Objective To establish and modify quantitative real-time polymerase chain reaction(qPCR)-based serotyping assays to distinguish 97 pneumococcal *** A database of capsular polysaccharide(cps)loci sequences was generated,covering 97 pneumococcal *** analyses were performed to identify the cps loci structure and target genes related to different pneumococcal serotypes with specific SNPs.A total of 27 novel qPCR serotyping assay primers and probes were established based on qPCR,while 27 recombinant plasmids containing serotype-specific DNA sequence fragments were constructed as reference target sequences to examine the specificity and sensitivity of the qPCR assay.A panel of pneumococcal reference strains was employed to evaluate the capability of pneumococcal *** A total of 97 pneumococcal serotyping assays based on qPCR were established and modified,which included 64 serotypes previously reported as well as an additional 33 ***-seven novel qPCR serotyping target sequences were implemented in the pneumococcal qPCR serotyping system.A total of 97 pneumococcal serotypes,which included 52 individual serotypes and 45 serotypes belonging to 20 serogroups,could not be identified as individual *** sensitivity of qPCR assays based on 27 target sequences was 1–100 copies/μ*** specificity of the qPCR assays was 100%,which were tested by a panel of 90 serotypes of the pneumococcal reference *** A total of 27 novel qPCR assays were established and modified to analyze 97pneumococcal serotypes.

关键词： Streptococcus pneumoniae Serotyping cps loci Quantitative real-time PCR(qPCR)