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125篇 您的检索式:作者名="Yanfei Chen"
    题名 作者 年代 出处 被引量
1Hybrid Material of Graphene and Poly(3,4-ethyldioxythiophene)with High Conductivity,Flexibility,and Transparency显示文摘A novel hybrid material prepared from graphene and poly(3,4-ethyldioxythiophene)(PEDOT)shows excellent transparency,electrical conductivity,and good flexibility,together with high thermal stability and is easily processed in both water and organic solvents.Conductivities of the order of 0.2 S/cm and light transmittance of greater than 80%in the 4001800 nm wavelength range were observed for fi lms with thickness of tens of nm.Practical applications in a variety of optoelectronic devices are thus expected for this transparent and flexible conducting graphene-based hybrid material。Yanfei Xu Yan Wang Jiajie Liang Yi Huang Yanfeng Ma Xiangjian Wan Yongsheng Chen 2009Nano Research2009,2,4:23
2Recanalization of extracranial internal carotid artery occlusion A 12-year retrospective study显示文摘This study aimed to summarize therapy experience of carotid endarterectomy, carotid endarterec-tomy combined with Fogarty catheter embolectomy, and hybrid surgery for the treatment of extrac-ranial internal carotid artery occlusion. The study included 65 patients with extracranial internal ca-rotid artery occlusion who underwent carotid endarterectomy, carotid endarterectomy combined with Fogarty catheter embolectomy, or hybrid surgery in the Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, China between January 2006 and December 2012. Prior to surgery, all patients underwent perfusion CT or xenon CT to evaluate the occlusion. The procedure for each patient was chosen according to digital subtraction angiography data. The carotid artery was successfully recanalized in 46 of 51 patients who underwent carotid endarterectomy, 9 of 10 patients who underwent carotid endarterectomy combined with Fogarty catheter embolectomy, and 3 of 4 patients who underwent hybrid surgery. In patients with symptomatic carotid artery occlusion, the carotid artery can be recanalized by choosing a treatment procedure based on imaging ex-amination findings.Liqun Jiao Gang Song Yang Hua Yan Ma Yanfei Chen Yabing Wang Feng Ling 2013Neural Regeneration Research2013,8,23:19
3Current Situation of Heavy Metal Pollution in Farmland Soil and Phytoremediation Application显示文摘Phytoremediation technology is a newly-developed way of soil heavy metal pollution repair with high efficiency and good ecological comprehensive benefit. This paper briefly introduces the soil heavy metal pollution status at home and abroad,and focuses on the analysis of harm,sources and current situation of soil heavy metal pollution at home and abroad as well as mechanism and application of phytoremediation.Finally it discusses the key problems in phytoremediation technology that need to resolve in the future.Yanfei HUANG Guifen CHEN Liumei XIONG Yuyi HUANG 2016Asian Agricultural Research2016,8,1:15
4Generation of B Cell-Deficient Pigs by Highly Efficient CRISPR/Cas9-Mediated Gene Targeting显示文摘Generating B cell-deficient mutant is the first step to produce human antibody repertoires in large animal models. In this study, we applied the clustered regularly interspaced short palindromic repeat(CRISPR)/CRISPR-associated(Cas) system to target the JHregion of the pig Ig M heavy chain gene which is crucial for B cell development and differentiation. Transfection of Ig M-targeting Cas9 plasmid in primary porcine fetal fibroblasts(PFFs) enabled inducing gene knock out(KO) in up to 53.3% of colonies analyzed, a quarter of which harbored biallelic modification, which was much higher than that of the traditional homologous recombination(HR). With the aid of somatic cell nuclear transfer(SCNT) technology, three piglets with the biallelic Ig M heavy chain gene mutation were produced. The piglets showed no antibody-producing B cells which indicated that the biallelic mutation of the Ig M heavy chain gene effectively knocked out the function of the Ig M and resulted in a B cell-deficient phenotype. Our study suggests that the CRISPR/Cas9 system combined with SCNT technology is an efficient genome-editing approach in pigs.Fengjiao Chen Ying Wang Yilin Yuan Wei Zhang Zijian Ren Yong Jin Xiaorui Liu Qiang Xiong Qin Chen Manling Zhang Xiaokang Li Lihua Zhao Ze Li Zhaoqiang Wu Yanfei Zhang Feifei Hu Juan Huang Rongfeng Li Yifan Dai 2015Journal of Genetics and Genomics2015,42,8:15
5Effects of Rare Earth elements on microstructure evolution and mechanical properties of 718H pre-hardened mold steel显示文摘718 H Pre-ha rdened mold steels with diffe rent Rare Earth(RE) contents were prepared to investigate the influence of RE on microstructure evolution and mechanical properties through a series of experiments and theoretical analysis.The results indicated that the toal oxygen(T.O) content decreased from 15 ppm to 6 ppm with 0.022 wt% RE addition,which is attributed to the active chemical properties of RE elements.For test steels,RE additions of 0.012 wt% and 0.022 wt% were significantly effective for refining inclusions by eliminating 11.5% large-sized inclusions with diameter exceeding 10 μm compared with that of ORE steel.RE addition contributed to modify irregular MnS and Al2 O3 inclusions into ellipsoidal RE-inclusions(RE2 O,RES,RE2 O2 S and REAlO3).The purification of molten steel and the modification of inclusions by RE treatment have significant effects on improvement of the fatigue crack growth tests(FCG) inhibition ability and impact energy as well as the isotropy.However,excessive addition of RE elements(0.07 wt%)seriously reduced the impact energy,ultimate tensile strength and FCG inhibition ability due to rapidly increase of the volume fraction of large-sized inclusions.In addition to the inclusions formed by RE treatment,trace solid solution RE atoms improve the stability of undercooled austenite,resulting in the transformation region of bainite and perlite of 0.07 RE steel shifting to the bottom right and prolonging the incubation period compared with that of ORE steel.Hanghang Liu Paixian Fu Hongwei Liu Yanfei Cao Chen Sun Ningyu Du Dianzhong Li 2020Journal of Materials Science & Technology2020,47,15:11
6Regional Distribution and Sustainable Development Strategy of Mineral Resources in China显示文摘This paper summarizes the distribution and production layout of the major mineral resources in China,including coal,iron ore,copper and bauxite,from a national perspective.It also identifies the incompatibility between the mineral resources distribution and regional economic development.Significant issues with China's mineral resource industry cause challenges for the sustainable development of both the mining industry and the national socio-economy.The sustainability of regional mineral resources and the environmental pollution by mining in the western China were also analyzed.Results show that the distribution of China's mineral resources is misaligned with its regional layout of economic development.China's mineral resources have been over-exploited,and the mineral resources production in the eastern China is unsustainable.The continuously expanding production of mineral resources in the western China has heavily endangered the ecological environment.We propose strategies to boost the sustainable development of mineral resources,including measures to accelerate economic development and enhance the sustainability of domestic mineral resources.We also offer suggestions for scientifically planning the mineral resource prospecting and exploitation and regional economic layout,as well as for proactively undertaking industry transfer in the eastern China and raising the environmental benchmark requirements for the mineral industry in the central and western China.LI Chaofeng WANG Anjian CHEN Xiaojin CHEN Qishen ZHANG Yanfei LI Ying 2013Chinese Geographical Science2013,23,4:11
7Expert consensus on the glycemic management of critically ill patients显示文摘Introduction The incidence of hyperglycemia is 40-60%in critically ill patients and is up to 60-80%in those who have undergone car-diac surgery.[1]The results of an epidemiological study in the United States showed that 28.6%of diabetic patients and 9.3%of non-diabetic patients had elevated mean daily glucose on the day of ICU admission.[2]In critically ill patients,elevated blood glucose is primarily the result of stress,and stress-induced hy-perglycemia is an independent risk factor associated with prog-nosis,regardless of a previous diagnosis of diabetes.Nutritional therapy has become an integral treatment option for patients in the ICU,[3,4]though nearly 30%of patients with enteral nu-trition and 44-50%with parenteral nutrition(PN)experience elevated glucose.[5,6]Intensive insulin therapy(IIT)is an impor-tant treatment for controlling hyperglycemia in critically ill pa-tients,but it also carries a corresponding risk of hypoglycemia.Zhixiong Wu Jiao Liu Dong Zhang Kai Kang Xiangrong Zuo Qianghong Xu Aijun Pan Wei Fang Fen Liu You Shang Haiyan Yin Juntao Hu Jinglun Liu Jiangquan Fu Wei Zhang Yuan Zong Min Shao Feng Zhao Mei Meng Yanfei Mao Yingchuan Li Dechang Chen 2022Journal of Intensive Medicine2022,2,3:9
8Improvement in collapsibility of ZrO2 ceramic mould for investment casting of TiAl alloys显示文摘Investment casting has been widely recognized as the best option in producing TiAl components with key benefits of accuracy,versatility and integrity.The collapsibility of ceramic moulds for investment casting is critical in the manufacturing process of TiAl components due to TiAl's intrinsic brittleness at room temperature.The aim of the present research is to provide a method for production of TiAl components by investment casting in ZrO2 ceramic moulds with improved collapsibility.Slurries prepared with high polymer additions were utilized during the preparation of ceramic moulds.The stress/strain curves obtained from green and baked ceramic moulds demonstrate that the green strength was increased with the application of high polymer,while baked strength decreased,thus the collapsibility of ceramic moulds was improved.It is suggested that this result is related to the burn-out of high polymer which left a lot of cavities.The experimental findings were also verified by the investment casting of 'I'-shaped TiAl components.Chen Yanfei Xiao Shulong Tian Jing Xu Lijuan Kong Fantao Chen Yuyong 2011China Foundry2011,8,1:8
9Realization of population inversion between 7S_(1/2) and 6P_(3/2) levels of cesium for four-level active optical clock显示文摘We demonstrate experimentally the population inversion between 7S1/2 and 6P3/2 levels of cesium in thermal cesium cell with a 455.5 nm pumping laser.We calculate the relative population probabilities at each level theoretically with the density matrix method.In a steady state,5.8% atoms are at 7S1/2 level and 2.9% at 6P3/2 level,which builds up the population inversion between the two levels.We obtain the fluorescence spectra produced in thermal cesium cell in our experiment.The measured relative intensity of each available fluorescence spectral line in the experiment agrees very well with the theoretical result.The demonstrated population inversion between 7S1/2 and 6P3/2 levels can be used to construct an active optical clock of four-level system with a wavelength of 1469.9 nm.WANG YanFei WANG DongYing ZHANG TongGang HONG YeLong ZHANG ShengNan TAO ZhiMing XIE XiaoPeng CHEN JingBiao 2013Science China(Physics,Mechanics & Astronomy)2013,56,6:6
10N-doped porous carbon nanofibers sheathed pumpkin-like Si/C composites as free-standing anodes for lithium-ion batteries显示文摘Dramatic capacity fading and poor rate performance are two main obstacles that severely hamper the widespread application of the Si anode owing to its large volume variation during cycling and low intrinsic electrical conductivity.To mitigate these issues,free-standing N-doped porous carbon nanofibers sheathed pumpkin-like Si/C composites(Si/C-ZIF-8/CNFs)are designed and synthesized by electrospinning and carbonization methods,which present greatly enhanced electrochemical properties for lithium-ion battery anodes.This particular structure alleviates the volume variation,promotes the formation of stable solid electrolyte interphase(SEI)film,and improves the electrical conductivity.As a result,the as-obtained free-standing Si/C-ZIF-8/CNFs electrode delivers a high reversible capacity of 945.5 mAh g^(-1) at 0.2 A g^(-1) with a capacity retention of 64% for 150 cycles,and exhibits a reversible capacity of 538.6 mA h g^(-1) at 0.5 A g^(-1) over 500 cycles.Moreover,the full cell composed of a freestanding Si/C-ZIF-8/CNFs anode and commercial LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(NCM)cathode shows a capacity of 63.4 mA h g^(-1) after 100 cycles at 0.2 C,which corresponds to a capacity retention of 60%.This rational design could provide a new path for the development of high-performance Si-based anodes.Yanfei Zeng Yudai Huang Niantao Liu Xingchao Wang Yue Zhang Yong Guo Hong-Hui Wu Huixin Chen Xincun Tang Qiaobao Zhang 2021Journal of Energy Chemistry2021,30,3:6
11High-entropy rare-earth zirconate ceramics with low thermal conductivity for advanced thermal-barrier coatings显示文摘The high-entropy rare-earth zirconate((La_(0.2)Nd_(0.2)Sm_(0.2)Gd_(0.2)Yb_(0.2))_(2)Zr_(2)O_(7),5RE_(2)Zr_(2)O_(7)HEREZs)ceramics were successfully prepared by a new high-speed positive grinding strategy combined with solid-state reaction method.The microstructure,crystal structure,phase composition,and thermophysical and mechanical properties of the samples were systematically investigated through various methods.Results indicate that the samples have a single-phase defect fluorite-type crystal structure with excellent high-temperature thermal stability.The as-prepared samples also demonstrate low thermal conductivity(0.9–1.72 W·m^(−1)·K^(−1)at 273–1273 K)and high coefficient of thermal expansion(CTE,10.9×10^(−6)K^(−1)at 1273 K),as well as outstanding mechanical properties including large Young’s modulus(E=186–257 GPa)and high fracture toughness(KIC).Furthermore,the formation possibility of the as-prepared samples was verified through the first-principles calculations,which suggested the feasibility to form the 5RE_(2)Zr_(2)O_(7)HE-REZs in the thermodynamic direction.Therefore,in view of the excellent multifunctional properties exhibited by the as-prepared 5RE_(2)Zr_(2)O_(7)HE-REZs,they have great potential applications in next-generation thermal-barrier coatings(TBCs).Debao LIU Baolu SHI Liyan GENG Yiguang WANG Baosheng XU Yanfei CHEN 2022Journal of Advanced Ceramics2022,11,6:6
12Active optical clock based on four-level quantum system显示文摘Active optical clock,a new conception of atomic clock,has been proposed recently.In this work,we propose a scheme of active optical clock based on four-level quantum system.The final accuracy and stability of two-level quantum system are limited by second-order Doppler shift of thermal atomic beam.To three-level quantum system,they are mainly limited by light shift of pumping laser field.These limitations can be avoided effectively by applying the scheme proposed here.Rubidium atom four-level quantum system,as a typical example,is discussed.The population inversion between 6S 1/2 and 5P 3/2 states can be built up at a time scale of 10-6 s.With the mechanism of active optical clock,in which the cavity mode linewidth is much wider than that of the laser gain profile,it can output a laser with quantum-limited linewidth narrower than 1 Hz in theory.An experimental configuration is designed to realize this active optical clock.ZHANG TongGang WANG YanFei ZANG XiaoRun ZHUANG Wei CHEN JingBiao 2013Chinese Science Bulletin2013,58,18:6
13Towards Flexible All-Carbon Electronics:Flexible Organic Field-Effect Transistors and Inverter Circuits Using Solution-Processed All-Graphene Source/Drain/Gate Electrodes显示文摘Flexible organic field-effect transistors(OFETs)using solution-processable functionalized graphene for all the electrodes(source,drain,and gate)have been fabricated for the first time.These OFETs show performance comparable to corresponding devices using Au electrodes as the source/drain electrodes on SiO2/Si substrates with Si as the gate electrode.Also,these devices demonstrate excellent flexibility without performance degradation over severe bending cycles.Furthermore,inverter circuits have been designed and fabricated using these all-graphene-electrode OFETs.Our results demonstrate that the long-sought dream for all-carbon and flexible electronics is now much closer to reality.Yongsheng Chen Yanfei Xu Kai Zhao Xiangjian Wan Jiachun Deng Weibo Yan 2010Nano Research2010,3,10:5
14Progress in green and efficient enrichment of rare earth from leaching liquor of ion adsorption type rare earth ores显示文摘Ion adsorption type rare earth ores(IATREOs)are a valuable strategic mineral resource in China,which feature a complete composition of fifteen rare earth elements and are rich in medium and heavy rare earth(RE)elements.In the leaching process for recovering rare earth elements from IATREOs,many impurities will be leached together with rare earth elements and enter the leaching liquor.An impurity removal-precipitation enrichment technique is currently applied to selectively recovery rare earth elements from the leaching liquor with the high content of impurities and low concentration of rare earth elements by using ammonium bicarbonate in the industry.However,a high loss of rare earth elements and severe ammonia nitrogen pollution are caused by this process.Therefore,more beneficial impurities removal technologies,mainly for aluminum,and green enrichment technologies with lower pollution are now urgently needed.For this purpose,this paper analyzed two aspects of research progress in recent decades:the green separation of rare earth elements and aluminum from leaching liquor and the green and efficient enrichment of rare earth elements.Finally,an approach for the high-efficiency and green enrichment of rare earth elements from leaching liquor of the IATREOs is proposed in several aspects,including impurity inhibition leaching,neutralization and impurity removal,alkaline calcium and magnesium salt precipitation enrichment,and centrifugal extraction enrichment.Qiang He Jiang Qiu Jinfa Chen Miaomiao Zan Yanfei Xiao 2022Journal of Rare Earths2022,40,3:5
15Over-sampling algorithm for imbalanced data classification显示文摘For imbalanced datasets, the focus of classification is to identify samples of the minority class. The performance of current data mining algorithms is not good enough for processing imbalanced datasets. The synthetic minority over-sampling technique(SMOTE) is specifically designed for learning from imbalanced datasets, generating synthetic minority class examples by interpolating between minority class examples nearby. However, the SMOTE encounters the overgeneralization problem. The densitybased spatial clustering of applications with noise(DBSCAN) is not rigorous when dealing with the samples near the borderline.We optimize the DBSCAN algorithm for this problem to make clustering more reasonable. This paper integrates the optimized DBSCAN and SMOTE, and proposes a density-based synthetic minority over-sampling technique(DSMOTE). First, the optimized DBSCAN is used to divide the samples of the minority class into three groups, including core samples, borderline samples and noise samples, and then the noise samples of minority class is removed to synthesize more effective samples. In order to make full use of the information of core samples and borderline samples,different strategies are used to over-sample core samples and borderline samples. Experiments show that DSMOTE can achieve better results compared with SMOTE and Borderline-SMOTE in terms of precision, recall and F-value.XU Xiaolong CHEN Wen SUN Yanfei 2019Journal of Systems Engineering and Electronics2019,30,6:5
16Decomposition of ammonium sulfate residue in a high solid/gas ratio suspension state with an industrial-scale reactor system(production line)显示文摘Ammonium sulfate residue is a particulate solid and is produced during the manufacture of ammonium sulfate fertilizer.The residue used in this study contained a large portion of calcium carbonate,from which active lime(CaO) was recovered via thermal decomposition.We used a purpose-built device to decompose the residue in a semi-suspension state.We found that CaO had the highest activity when residue was decomposed at 850-900 ℃.Our experiments indicated that ammonium sulfate residue should be decomposed in a suspension state to produce active CaO.Based on our laboratory test findings,an industrial-scale production line with a high solid/gas ratio in a suspension state was devised.The optimal operating conditions for the decomposition of the ammonium sulfate residue to produce high quality CaO were also investigated.We found that the CaCO_3 decomposition rate was high and the CaO product was highly active,averaging 170 s by the citric acid method.Morphology measurements showed that the CaO product had a porous structure and a large specific surface ensuring high activity.Qi Li Delong Xu Yanxin Chen Yanfei Yao Zhi Sun Songxiong Ding 2015Particuology2015,13,5:4
17Characterization of zirconia-based slurries with different binders for titanium investment casting显示文摘The materials and physical properties of primary slurry are crucial to the surface quality of the finished castings,especially for high reactivity titanium alloys.The aim of this study is to investigate the influence of different binders on the physical properties of primary slurry for titanium alloy investment casting.The zirconia-based slurries with different binders were evaluated by comparing the parameters:viscosity,bulk density,plate weight, suspensibility,gel velocity and strength.The results indicate that a higher viscosity of binder leads to a higher viscosity and suspensibility of slurry with the same powder/binder ratio.The retention rate and thickness of primary layer increase with an increase in the viscosity of the slurry,and a higher retention rate is associated with a thicker primary layer.The gel velocity of the slurry is correlated with the gel velocity of the binder.The green strength and the baked strength of the primary layer are determined by the properties of the binder after gel and by the production of the binder after fired,respectively.Zhao Ertuan Kong Fantao Chen Yanfei Chen Ruirun Chen Yuyong 2012China Foundry2012,9,2:4
18Numerical experiment rock fragmentation by combined dynamic and static loads under dual-cutter head显示文摘This paper puts forward a new rock fragmentation loading method of dual-cutter head combined dynamic and static loads.By applying the numerical simulation software-RFPA2D,we have done numerical experiment about the siltstone's crushing effect by dynamic load on single cutter head without confining pressure,dynamic load on single cutter head with confining pressure 10MPa and different dual-cutter heads spacing by combined dynamic and static loads with confining pressure 10MPa.Experimental results show that the confining pressure can obviously affect the rock fragmentation effect.Combined dynamic and static loads can greatly improve the rock fragmentation effect.There exists an optimal spacing of dual-cutter head that can make the rock fragmentation achieve the desired effect.Through analyzing the acoustic emission accumulative energy and quantity,the authors make a conclusion that the optimum spacing is 30 mm.Zhao Fujun Wang Hongyu Shen Peiwen Chen Caixian Xu Yanfei 2012Engineering Sciences2012,10,2:3
19Advances in Studies on Interaction between Selenium and Heavy Metal Cadmium显示文摘Selenium is an essential functional element of the human body,and the issue of selenium accompanying heavy metals is receiving much concern.This paper expounded the form of existence of selenium and cadmium in soil and influencing factors of their bioavailability,and further elaborated the interaction between selenium and cadmium.On the basis,it provided references for further studies on the interaction between selenium and cadmium,and provided basis for establishing selenium-enriched barrier technology for crops.Liping PAN Yongxian LIU Yanfei HUANG Mengling NONG Shiyang LU Jinping CHEN Yuying ZHAO Liumei XIONG Xiu LAN Kebing LI 2017Asian Agricultural Research2017,9,8:3
20Remediation Technology for Combined Pollution of Lead and Cadmium in Farmland Soil显示文摘At present,the problem of heavy metal pollution in farmland in southern China is serious. Especially,the cadmium and lead are two heavy metal elements with serious pollution and great harm to human body. This paper reviewed some common methods and materials used in the control of cadmium and lead pollution in farmland soil. Then,it discussed the problems in the repair of cadmium and lead pollution in farmland soil. It came up with the future research direction,to provide references for remediation of lead and cadmium pollution in farmland soil.Jun TAN Yongxian LIU Xiangfeng WEI Yanfei HUANG Liumei XIONG Liping PAN Jinping CHEN Bin LIU Chaolan ZHANG 2018Asian Agricultural Research2018,10,9:3
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