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| 1 | Joint Beamforming Optimization for Reconfigurable Intelligent Surface-Enabled MISO-OFDM Systems显示文摘In this paper,we investigate the reconfigurable intelligent surface(RIS)-enabled multiple-input-single-output orthogonal frequency division multiplexing(MISO-OFDM)system under frequency-selective channels,and propose a low-complexity alternating optimization(AO)based joint beamforming and RIS phase shifts optimization algorithm to maximize the achievable rate.First,with fixed RIS phase shifts,we devise the optimal closedform transmit beamforming vectors corresponding to different subcarriers.Then,with given active beamforming vectors,near-optimal RIS reflection coefficients can be determined efficiently leveraging fractional programming(FP)combined with manifold optimization(MO)or majorization-minimization(MM)framework.Additionally,we also propose a heuristic RIS phase shifts design approach based on the sum of subcarrier gain maximization(SSGM)criterion requiring lower complexity.Numerical results indicate that the proposed MO/MM algorithm can achieve almost the same rate as the upper bound achieved by the semidefinite relaxation(SDR)algorithm,and the proposed SSGM based scheme is only slightly inferior to the upper bound while has much lower complexity.These results demonstrate the effectiveness of the proposed algorithms. | Keming Feng Xiao Li Yu Han Yijian Chen | 2021 | China Communications2021，18，3： | 6 |
| 2 | Facile synthesis of hierarchical Na2Fe(SO4)2@rGO/C as high-voltage cathode for energy density-enhanced sodium-ion batteries显示文摘Fe-based sulfates are ideal cathode candidates for sodium-ion batteries(SIBs) owing to their high operating voltage and low cost but suffer from the nature of poor power performance. Herein, a hierarchical porous Na2Fe(SO4)2@reduced graphene oxide/carbon dot(Na2Fe(SO4)2@rGO/C) with low carbon content(4.12 wt%) was synthesized via a facile homogeneous strategy benefiting for engineering application,which delivers excellent sodium storage performance(high voltage plateau of 3.75 V, 85 m Ah g-1 and330 Wh kg-1 at 0.05 C;5805 W kg-1 at 10 C) and high Na+diffusion coefficient(1.19 × 10-12 cm2 s-1).Moreover, the midpoint voltage of assembled full cell could reach 3.0 V. The electron transfer and reaction kinetics are effectively boosted since the nanoscale Na2Fe(SO4)2 is supported by a robust crosslinked carbon matrix with rGO sheets and carbon dots. The slight rGO sheets sufficiently enhance the electron transfer like a current collecter and restrain the aggregation, as well as ensure smooth ion channels. Meanwhile, the carbon dots in the whole space connect with Na2Fe(SO4)2 and help rGO to promote the conductivity of the electrode. Ex-situ X-ray powder diffraction and X-ray photoelectron spectrometry analysis confirm the high reversibility of this sodiation/desodiation process. | Ge Yao Xixue Zhang Yongliang Yan Jiyu Zhang Keming Song Juan Shi Liwei Mi Jinyun Zheng Xiangming Feng Weihua Chen | 2020 | Journal of Energy Chemistry2020，29，11： | 3 |
| 3 | Analysis of single frequency modulation for passive hydrogen maser显示文摘Based on the theory of the passive hydrogen maser,along with the technology of frequency modulation and modulation transfer spectroscopy, the theoretical expression of the single frequency modulation for the passive hydrogen maser and the function of the cavity and H line error signals separation are derived, which are basically coincident with the experiment. The absorption and dispersion spectrum curves with different resonance widths show that the cavity and hydrogen transition serve as discriminators, and the two error signals can be separated.Through the calculations of the two error signals in the passive hydrogen maser, it analyzes the traditional method of the two error signals separation, and then describes a new improved method for the passive hydrogen servo loops consisting in the use of a single modulation frequency and frequency discrimination. A null interaction of the two error signals for the new selection of the phase setting is deduced theoretically and validated by the simulation.The preliminary experimental result confirms the feasibility of this new approach, which can reduce the influence from the cavity frequency variety on the crystal oscillator and contribute significantly to the long term performance of the passive hydrogen maser. | Hefei Zheng Jing Li Wenming Wang Lianshan Gao Keming Feng | 2017 | Journal of Systems Engineering and Electronics2017，28，4： | 2 |
| 4 | Drag Reduction Effect for Hypersonic Lifting-Body Vehicle with Counterflowing Jet显示文摘This study takes the novel approach of using a counterflowing jet positioned on the nose of a lifting-body vehicle to explore its drag reduction effect at a range of angles of attack.Numerical studies are conducted at a freestream Mach number of 8 in standard atmospheric conditions corresponding to the altitude of 40 km.The effects of jet pressure ratio and flying angles of attack on drag reduction of the model are systematically investigated.Considering the reverse thrust generated from the counterflowing jet,the drag on the nose at hypersonic speeds could be reduced up to 66%.The maximum lift-to-drag ratio of the model is obtained at 6°;meanwhile,the counterflowing jet produces a drag reduction of 8.8%for the whole model.In addition to the nose,the counterflowing jet influences the drag by increasing the pressure drag of the model and reducing the skin friction drag of the first cone within 8°.The results show that the potential of the counterflowing jet as a means of active flow control for drag reduction is significant in the engineering application on hypersonic lifting-body vehicles. | Dong Hao Deng Fan Xie Feng Geng Xi Cheng Keming | 2018 | Transactions of Nanjing University of Aeronautics and Astronautics2018，35，5： | 2 |
| 5 | Characteristics of Se-Enriched Mycelia by Stropharia rugoso-annulata and its Antioxidant Activities in vivo显示文摘 | Zhen Song Le Jia Feng Xu Fanyun Meng Peng Deng Keming Fan Xiaonan Liu | 2009 | Biological Trace Element Research2009，，1： | 1 |
| 6 | Time-course of programmed cell death during leaf senescence in Eucommia ulmoides显示文摘 | Jing Cao Feng Jiang Sodmergen Keming Cui | 2003 | Journal of Plant Research2003，，1： | 1 |
| 7 | Screening for and surveillance of high-risk patients with HBV-related chronic liver disease:Promoting the early detection of hepatocellular carcinoma in China显示文摘 | Peipei Song Xiaobin Feng Keming Zhang | 2013 | BioScience Trends2013，7，1： | 1 |
| 8 | Hydrogen evolution-assisted one-pot aqueous synthesis of hierarchical trimetallic PdNiRu nanochains for hydrazine oxidation reaction显示文摘A hydrogen evolution-assisted one-pot aqueous approach was developed for facile synthesis of trimetallic Pd Ni Ru alloy nanochain-like networks(Pd Ni Ru NCNs) by only using KBH_4 as the reductant, without any specific additive(e.g. surfactant, polymer, template or seed). The products were mainly investigated by transmission electron microscopy(TEM), X-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS). The hierarchical architectures were formed by the oriented assembly growth and the diffusioncontrolled deposition in the presence of many in-situ generated hydrogen bubbles. The architectures had the largest electrochemically active surface area(ECSA) of 84.32 m^2 g^(–1) Pdthan Pd Ni nanoparticles(NPs,65.23 m^2 g^(–1) Pd), Pd Ru NPs(23.12 m^2 g^(–1) Pd), Ni Ru NPs(nearly zero), and commercial Pd black(6.01 m^2 g^(–1) Pd), outperforming the referenced catalysts regarding the catalytic characters for hydrazine oxygen reaction(HOR). The synthetic route provides new insight into the preparation of other trimetallic nanocatalysts in fuel cells. | Tao Yuan Aijun Wang Keming Fang Zhigang Wang Jiuju Feng | 2017 | Journal of Energy Chemistry2017，26，6： | 1 |
| 9 | Recycling Carbon Resources from Waste PET to Reduce Carbon Dioxide Emission:Carbonization Technology Review and Perspective显示文摘Greenhouse gas emissions from waste plastics have caused global warming all over the world,which has been a central threat to the ecological environment for humans,flora and fauna.Among waste plastics,waste polyethylene terephthalate(PET)is attractive due to its excellent stability and degradation-resistant.Therefore,merging China’s carbon peak and carbon neutrality goals would be beneficial.In this review,we summarize the current state-of-the-art of carbon emission decrease from a multi-scale perspective technologically.We suggest that the carbon peak for waste PET can be achieved by employing the closed-loop supply chain,including recycling,biomass utilization,carbon capture and utilization.Waste PET can be a valuable and renewable resource in the whole life cycle.Undoubtedly,all kinds of PET plastics can be ultimately converted into CO_(2),which can also be feedstock for various kinds of chemical products,including ethyl alcohol,formic acid,soda ash,PU,starch and so on.As a result,the closed-loop supply chain can help the PET plastics industry drastically reduce its carbon footprint. | Xing Zhou Qi Wang Sai Feng Jingrui Deng Keming Zhu Yun Xing Xiaolian Meng Xiaojun Wang Lu Li | 2023 | Journal of Renewable Materials2023，11，5： | 0 |
| 10 | Evolution of Meteorological Conditions during a Heavy Air Pollution Event under the Influence of Shallow Foehn in Urumqi, China显示文摘The air pollution in Urumqi which is located on the northern slope of the Tianshan Mountains in northwestern China,is very serious in winter.Of particular importance is the influence of terrain-induced shallow foehn,known locally as elevated southeasterly gale(ESEG).It usually modulates atmospheric boundary layer structure and wind field patterns and produces favorable meteorological conditions conducive to hazardous air pollution.During 2013-17,Urumqi had an average of 50 d yr-1 of heavy pollution(daily average PM2.5 concentration>150μg m-3),of which 41 days were in winter.The majority(71.4%)of heavy pollution processes were associated with the shallow foehn.Based on microwave radiometer,wind profiler,and surface observations,the surface meteorological fields and boundary layer evolution during the worst pollution episode in Urumqi during 16-23 February 2013 are investigated.The results illustrate the significant role of shallow foehn in the building,strengthening,and collapsing of temperature inversions.There were four wind field patterns corresponding to four different phases during the whole pollution event.The most serious pollution phase featured shallow foehn activity in the south of Urumqi city and the appearance of an intense inversion layer below 600 m.Intense convergence caused by foehn and mountain-valley winds was sustained during most of the phase,resulting in pollutants sinking downward to the lower boundary layer and accumulating around urban area.The key indicators of such events identified in this study are highly correlated to particulate matter concentrations and could be used to predict heavy pollution episodes in the feature. | Xia LI Keming ZHAO Shiyuan ZHONG Xiaojing YU Zhimin FENG Yuting ZHONG Ayitken MAULEN Shuting LI | 2023 | Advances in Atmospheric Sciences2023，40，1： | 0 |
| 11 | RIN enhances plant disease resistance via root exudate-mediated assembly of diseasesuppressive rhizosphere microbiota显示文摘The RIPENING-INHIBITOR(RIN)transcriptional factor is a key regulator governing fruit ripening.While RIN also affects other physiological processes,its potential roles in triggering interactions with the rhizosphere microbiome and plant health are unknown.Here we show that RIN affects microbiome-mediated disease resistance via root exudation,leading to recruitment of microbiota that suppress the soil-borne,phytopathogenic Ralstonia solanacearum bacterium.Compared with the wild-type(WT)plant,RIN mutants had different root exudate profiles,which were associated with distinct changes in microbiome composition and diversity.Specifically,the relative abundances of antibiosis-associated genes and pathogensuppressing Actinobacteria(Streptomyces)were clearly lower in the rhizosphere of rin mutants.The composition,diversity,and suppressiveness of rin plant microbiomes could be restored by the application of 3-hydroxyflavone and riboflavin,which were exuded in much lower concentrations by the rin mutant.Interestingly,RIN-mediated effects on root exudates,Actinobacteria,and disease suppression were evident from the seedling stage,indicating that RIN plays a dual role in the early assembly of diseasesuppressive microbiota and late fruit development.Collectively,our work suggests that,while plant disease resistance is a complex trait driven by interactions between the plant,rhizosphere microbiome,and the pathogen,it can be indirectly manipulated using'prebiotic'compounds that promote the recruitment of disease-suppressive microbiota. | Keming Yang Ruixin Fu Haichao Feng Gaofei Jiang Omri Finkel Tianyu Sun Mingchun Liu Baowen Huang Shan Li Xiaofang Wang Tianjie Yang Yikui Wang Shimei Wang Yangchun Xu Qirong Shen Ville-Petri Friman Alexandre Jousset Zhong Wei | 2023 | Molecular Plant2023，16，9： | 0 |
| 12 | Ultrafast optoelectronic technology for radio metrology applications显示文摘Ultrafast optoelectronic technology has been widely used in terahertz time domain spectrum,terahertz imaging technology,terahertz communication and so on,and great progress has been achieved in the past two decade.Recently,this innovative technology has been applied in radio metrology and supplied a potential and hopeful method to solve the existent challenges of calibration devices and equipments with bandwidth up to 100 GHz.This paper generally summarizes the emerging applications of the ultrafast optoelectronic technology in radio metrology.The main applications of this technology in calibrating broadband sampling oscilloscopes,the high-speed photodiodes and calibrating the electrical pulse generators are emphasized,and the testing of monolithic microwave integrated circuits is also presented. | Zhe Ma Hongmei Ma Pengwei Gong Chuntao Yang Keming Feng | 2010 | Journal of Systems Engineering and Electronics2010，21，3： | 0 |
| 13 | Research on frequency-temperature compensated sapphire-SrTiO_3 loaded cavity for hydrogen maser显示文摘To obtain frequency-temperature compensation in a sapphire loaded cavity for hydrogen maser,a dielectric named SrTiO_3 is employed whose temperature coefficient of permittivity is opposite to that of sapphire. Based on theoretical analysis and computer simulation,a TE_(011) mode of a sapphire loaded cavity associated with two small rings of SrTiO_3 with different thickness is solved,and the useful parameters that influence the temperature coefficient of cavity are calculated.Finally an experiment is brought forward and its results are very close to the computing results.When the thickness of SiTiO_3 dielectric is 7 mm and the diameter is 17 mm in configuration b, the temperature coefficient of cavity is decreased from -58.8 kHz/K to -8.2 kHz/K and the quality factor is 40248. | Wang Nuanrang Zhou Tiezhong Gao Lianshan Yang Chuntao Feng Keming | 2009 | Journal of Systems Engineering and Electronics2009，20，4： | 0 |
| 14 | Modeling of terahertz pulse generation from LT-GaAs ultrafast photoconductive switches显示文摘The technique of terahertz pulses generated from the photoconductive switches has been applied in the ultrafast electrical pulse metrology recently.A lumped-element theoretical model is established to describe the performance of the LT-GaAs ultrafast photoconductive switch used in the ultrafast pulse standard.The carrier transport processes of the photoexcited semiconductor,the attenuation and dispersion during terahertz pulse propagating are considered in the theoretical model.According to the experimental parameters,the waveforms of the generated terahertz pulses are calculated under optical excitations with different wavelengths of 840 nm and 450 nm,respectively.And comparisons between the theoretical results and the experimental results are carried out. | Zhe Ma ongmei Ma Chuntao Yang Keming Feng | 2011 | Journal of Systems Engineering and Electronics2011，22，3： | 0 |
| 15 | Technology and test results of space adaptability of passive hydrogen maser显示文摘Based on the operating principle and the electric property design of the passive hydrogen maser, the technology and test results of its space adaptability are carried out under the special launch conditions and space environment. The various perturbations affecting the output frequency of such a standard used for the navigation satellite system are specified, such as magnetic field change, vibration, thermal vacuum and radiation. Through the adaptability technology in the aspects above, the security and reliability of the space passive hydrogen maser sufficiently fulfill the requirements of space operation. At present, the space passive hydrogen maser is working normally on board, indicating that the space adaptability satisfies the design requirement. | Hefei Zheng Lianshan Gao Keming Feng Jing Li Wenming Wang Chunyan Cao Jihong Zhang | 2017 | Journal of Systems Engineering and Electronics2017，28，2： | 0 |
| 16 | Improve Writing by Combining Reading and Writing显示文摘This paper gives the reason why writing in teaching has not been improved greatly in recent years and provides someactive suggestions of improving writing teaching. | Feng Keming Chen Xianglan(English Dep. Luliang Higher College Xizhou 033000 China) (English Dep. Xinzhou Teacher’s College Xizhou, 034000. China) | 2000 | 运城学院学报2000，20，S2： | 0 |
| 17 | Expert Consensus on Nutritional Support for Children with Congenital Heart Disease(2023 Edition)显示文摘The second edition of the expert consensus on pediatric nutrition was formed based on a global update of pedia-tric nutrition guidelines or consensus worldwide,the management of congenital heart disease,and the results of multi-center clinical nutrition research for congenital heart disease following thefirst Chinese consensus edition of 2016.The consensus was also shaped by the results of three discussion sessions and two questionnaires con-ducted by the 13-member collaboration group.This process was informed by both clinical guidelines and expert consensus.The quality of literature,both in English and Chinese,and the level of recommendations were evaluated using the Grading of Recommendations Assessment,Development,and Evaluations(GRADE)system. | Xuming Mo Wei Cai Jirong Qi Zhuoming Xu Ying Wang Weihui Yan Shoujun Li Nianguo Dong Xinxin Chen Jinfen Liu Qiang Shu Jimei Chen Haibo Zhang Hao Zhang Quansheng Xing Qi An Xiaofeng Li Xu Wang Yan He Junwu Su Taibing Fan Teng Ming Weibing Tang Li Hong Jinghao Zheng Ming Ye Guocheng Sun Yiqun Ding Liang Tao Yifeng Yang Zhongshi Wu Hua Cao Qiang Wang Keming Yang Libing Zhang Ping Wen Yanqin Cui Bo Zhai Yong Zou Qingya Tang Rui Chen Chun Wu Zhiyu Feng Caixia Liu Yaping Mi Rufang Zhang Ke Lin Xin Li Mingan Pi Xiangming Fan Shanshan Shi Peng Huang Zhengxia Pan Jiafeng Qi Renwei Chen Shuguang Tao Yaqin Shu Huifeng Zhang Lan Jiang Min Da Nishant Patel Liang Hu Cardiac Surgery Group of Pediatric Surgery Society of Chinese Medical Association and Parenteral Enteral Nutrition Society of Chinese Medical Association | 2023 | Congenital Heart Disease2023，18，6： | 0 |
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