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83篇 您的检索式:作者名="Chaofeng LI"
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1New eolian red clay sequence on the western Chinese Loess Plateau linked to onset of Asian desertification about 25 Ma ago显示文摘The expansion of inland Asia deserts has considerably influenced the environmental, social and economic activities in Asia. Aridification of inland Asia, especially timing of the initiation of Asian desertification, is a contentious topic in paleoclimatology. Late Cenozoic eolian loess-red clay sequences on the Chinese Loess Plateau, which possess abundant paleoclimatic and paleo-environmental information, can be regarded as an indicator of inland Asia desertification. Here we present a detailed magnetostratigraphic investigation of a new red clay sequence about 654 m in Zhuanglang located at the western Chinese Loess Plateau. Sedimentological, geochemical, mineralogical, and quartz morphological lines of evidence show that the red clay is of eolian origin. Magnetostratigraphic correlations indicate that this core sequence spans from 25.6 to 4.8 Ma, and typical eolian red clay appears as early as 25 Ma. This extends the lower limit of the red clay on the Chinese Loess Plateau from the previously thought early Miocene back into the late Oligocene. This new red clay record further implies that the inland Asia desertification was initiated at least by the late Oligocene. This sequence provides a unique high-resolution geological record for understanding the inland Asia desertification process since the late Oligocene.QIANG XiaoKe AN ZhiSheng SONG YouGui CHANG Hong SUN YouBin LIU WeiGuo AO Hong DONG JiBao FU ChaoFeng WU Feng LU FengYan CAI YanJun ZHOU WeiJian CAO JunJi XU XinWen AI Li 2011Science China Earth Sciences2011,54,1:73
2REE composition in scheelite and scheelite Sm-Nd dating for the Xuebaoding W-Sn-Be deposit in Sichuan显示文摘The scheelite with large size and euhedral shape from Xuebaoding, Sichuan Province is an ideal min- eral to study REE patterns and Sm-Nd dating of non-gold deposits. The scheelite has diameters of 1― 10 cm and colors of pale beige to deep orange. Most of these scheelites occur in association with beryl, cassiterite and muscovite. The rare earth elements indicate that scheelite samples from Xuebaoding W-Sn-Be deposits contain high concentrations of rare earth elements with total ΣREE+Y contents in the range of 369―1725 μg·g?1 and nearly all of these scheelite samples are enriched in LREE and depleted in HREE and have negative Eu anomalies. The REE patterns of the scheelites are similar to those of A-type granite with obvious tetrad effect, similar to that of type II scheelites. Based on reported fluid inclusion studies, the mineralizing-fluid of the Xuebaoding W-Sn-Be deposit indicates low Na activity. The REE patterns of the scheelite are probably controlled by partition coefficient in hydrothermal fluid. In the 147Sm/144Nd-143Nd/144Nd diagram, the scheelites show a linear array corresponding to an isochron age of 182.0±9.2 Ma (MSWD = 0.52). The Sm-Nd age represents the formation age of the scheelite and can indicate that the W, Sn and Be mineralization at Xuebaoding took place in the Early Yanshanian. The Sm-Nd dating result is important for the study of the multi-metal resources in western Sichuan Province.LIU Yan DENG Jun LI ChaoFeng SHI GuangHai ZHENG AiLi 2007Chinese Science Bulletin2007,52,18:25
3Ultra-low procedural blank and the single-grain mica Rb-Sr isochron dating显示文摘Both low procedural blank and high-precision measurements of isotopic ratios are crucial for the analysis of micro samples. This study reports a chemical procedure of ultra-low blank for the high precision measurement of Sr isotopic ratios on micro samples (<1 ng level) using a new-type thermal ionization mass spectrometer IsoProbe-T, with a case study of single-grain Rb-Sr isochron dating on phlogopite from the Fuxian kimberlite in Liaoning Province. This method can be employed in studies of high resolution Rb-Sr geochronology and Sr isotopic geochemistry and thus will broaden application of the Rb-Sr isotopic system to earth sciences.LI Qiuli HEN Fukun WANG Xiuli LI Xianghui LI Chaofeng 2005Chinese Science Bulletin2005,50,24:15
4Design and experimental study of a micro-groove grinding wheel with spray cooling effect显示文摘The effectiveness of grinding fluid supply has a crucial impact on grinding quality and efficiency in high speed grinding. In order to improve the cooling and lubrication, through in-depth research of self-inhaling internal cooling method and intermittent grinding mechanism, a new spray cooling method used in high speed grinding is proposed. By referring to the structure of bowlshaped dispersion disk, the grinding wheel matrix with atomization ability is designed; through studying heat transfer of droplet collision and the influence of micro-groove on the boiling heat transfer, grinding segment with micro-groove is designed to enhance the heat flux of coolant and achieve maximum heat transfer between droplets and grinding contact zone. High-speed grinding experiments on GH4169 with the developed grinding wheel are carried out. The results show that with the micro-groove grinding wheel just 5.4% of pump outlet flow rate and 0.5% of spindle energy is needed to reduce the grinding temperature to 200 C, which means the developed grinding wheel makes cooling high efficient and low energy consuming.Shi Chaofeng Li Xun Chen Zhitong 2014Chinese Journal of Aeronautics2014,27,2:14
5Processing of advanced thermoelectric materials显示文摘Last two decades have witnessed significant progress in thermoelectric research,to which materials processing has crucial contributions.Compared with traditional zone-melting method used for fabricating bismuth telluride alloys,new powder-based processes have more freedom for manipulating nanostructures and nanocomposites.Thermoelectric performance enhancement is realized in most thermoelectric materials by introducing fine-grained and nano-composite structures with accurately controlled compositions.This review gives a comprehensive summary on the processing aspects of thermoelectric materials with three focuses on the powder synthesis,advanced sintering process and the formation of nano structures in bulk materials.LI JingFeng PAN Yu WU ChaoFeng SUN FuHua WEI TianRan 2017Science China(Technological Sciences)2017,60,9:13
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
7Development and validation of an endoscopic images-based deep learning model for detection with nasopharyngeal malignancies显示文摘Background:Due to the occult anatomic location of the nasopharynx and frequent presence of adenoid hyperpla-sia,the positive rate for malignancy identification during biopsy is low,thus leading to delayed or missed diagnosis for nasopharyngeal malignancies upon initial attempt.Here,we aimed to develop an artificial intelligence tool to detect nasopharyngeal malignancies under endoscopic examination based on deep learning.Methods:An endoscopic images-based nasopharyngeal malignancy detection model(eNPM-DM)consisting of a fully convolutional network based on the inception architecture was developed and fine-tuned using separate training and validation sets for both classification and segmentation.Briefly,a total of 28,966 qualified images were collected.Among these images,27,536 biopsy-proven images from 7951 individuals obtained from January 1st,2008,to December 31st,2016,were split into the training,validation and test sets at a ratio of 7:1:2 using simple randomiza-tion.Additionally,1430 images obtained from January 1st,2017,to March 31st,2017,were used as a prospective test set to compare the performance of the established model against oncologist evaluation.The dice similarity coef-ficient(DSC)was used to evaluate the efficiency of eNPM-DM in automatic segmentation of malignant area from the background of nasopharyngeal endoscopic images,by comparing automatic segmentation with manual segmenta-tion performed by the experts.Results:All images were histopathologically confirmed,and included 5713(19.7%)normal control,19,107(66.0%)nasopharyngeal carcinoma(NPC),335(1.2%)NPC and 3811(13.2%)benign diseases.The eNPM-DM attained an overall accuracy of 88.7%(95%confidence interval(CI)87.8%-89.5%)in detecting malignancies in the test set.In the prospective comparison phase,eNPM-DM outperformed the experts:the overall accuracy was 88.0%(95%CI 86.1%-89.6%)vs.80.5%(95%CI 77.0%-84.0%).The eNPM-DM required less time(40 s vs.110.0±5.8 min)and exhibited encouraging performance in automatic segmentation of nasopharyngeal malignant area from the background,with an average DSC of 0.78±0.24 and 0.75±0.26 in the test and prospective test sets,respectively.Conclusions:The eNPM-DM outperformed oncologist evaluation in diagnostic classification of nasopharyngeal mass into benign versus malignant,and realized automatic segmentation of malignant area from the background of nasopharyngeal endoscopic images.Chaofeng Li Bingzhong Jing Liangru Ke Bin Li Weixiong Xia Caisheng He Chaonan Qian Chong Zhao Haiqiang Mai Mingyuan Chen Kajia Cao Haoyuan Mo Ling Guo Qiuyan Chen Linquan Tang Wenze Qiu Yahui Yu Hu Liang Xinjun Huang Guoying Liu Wangzhong Li Lin Wang Rui Sun Xiong Zou Shanshan Guo Peiyu Huang Donghua Luo Fang Qiu Yishan Wu Yijun Hua Kuiyuan Liu Shuhui Lv Jingjing Miao Yanqun Xiang Ying Sun Xiang Guo Xing Lv 2018Cancer Communications2018,38,1:9
8Energy storage through intercalation reactions:electrodes for rechargeable batteries显示文摘Electrochemical energy storage has been an important enabling technology for modern electronics of all kinds,and will grow in importance as more electric vehicles and grid-scale storage systems are deployed.We briely review the history of intercalation electrodes and basic concepts pertaining to bateries based on intercalation reactions.hen we summarize how the critical performance metrics—energy density,power density,safety and stability—relate back to electrode materials properties,and how these materials properties are related to fundamental chemical and physical structure relationships highlighted with the most recent research advancement.Challenges and avenues for further research have been highlighted throughout.Robert C.Massé Chaofeng Liu Yanwei Li Liqiang Mai Guozhong Cao 2017National Science Review2017,4,1:8
9Development and Analysis of an Electrically Actuated Lower Extremity Assistive Exoskeleton显示文摘一架电子上激活的更低的极限皮骨骼被开发,在哪个当有弹性的元素连接的另外的关节消极地被激活时,仅仅膝关节活跃地被激活。这份报纸描述批评设计标准并且介绍设计的进程和使活动系统的计算。一台灵活物理 Human-Robot-Interaction (pHRI ) 测量设备被设计并且适用检测人的运动,它包括纳入连接手铐的内部表面的二个力量传感器和二个气囊。联机适应 pHRI 最小化控制策略被建议并且实现了驱使机器的皮骨骼系统跟随人的手足的运动轨道。测量 pHRI 信息被变化加权的一般水准(VWA ) 方法熔化。pHRI 和控制转矩的吝啬的方形的价值(MSV ) 被利用评估皮骨骼的表演。改进舒适水平和还原剂精力消费,当控制法律被设计时,严肃赔偿被考虑。最后,实际实验在健康用户上被执行。试验性的结果证明建议系统能帮助人走,构画出的控制策略有效、有效。Yi Long Zhijiang Du Chaofeng Chen Weidong Wang Long He Xiwang Mao Guoqiang Xu Guangyu Zhao Xiaoqi Li Wei Dong 2017Journal of Bionic Engineering2017,14,2:7
10Dynamic Characteristics of Multi-degrees of Freedom System Rotor-bearing System with Coupling Faults of Rub-impact and Crack显示文摘Extensive studies on rotor systems with single or coupled multiple faults have been carried out. However these studies are limited to single-span rotor systems. A finite element model for a complex rotor-bearing system with coupled faults is presented. The dynamic responses of the rotor-bearing system are obtained by using the rotor dynamics theory and the modern nonlinear dynamics theory in connection with the continuation-shooting algorithm(commonly used for obtaining a periodic solution for a nonlinear system) for a range of rub-impact clearances and crack depths. The stability and Hopf instability of the periodic motion of the rotor-bearing system with coupled faults are analyzed by using the procedure described. The results indicate that the finite element method is an effective way for determining the dynamic responses of such complex rotor-bearing systems. Further for a rotor system with rub-impact and crack faults, the influences of the clearances are significantly different for different rub-impact stiffness. On the contrary, the influence of crack depths is rather small. The instability speeds of the rotor-bearing system increase due to the presence of the crack fault. The results obtained using the new finite element model, presented for computation and analysis of dynamic responses of the rotor-bearing systems with coupled faults, are in accordance with measurements in experiment. The formulations given can be used for diagnosis of faults, vibration control, and safe and stable operations of real rotor-bearing systems.REN Zhaohui ZHOU Shihua LI Chaofeng WEN Bangchun 2014Chinese Journal of Mechanical Engineering2014,27,4:7
11High-yield preparation of robust gold nanoshells on silica nanorattles with good biocompatiblity显示文摘Although gold nanoshells are widely considered as one of the promising photothermal nanomaterials used for biomedicine, the high cost, low yield and poor stability severely limit their potential application in clinical trials.Herein, robust gold nanoshells on silica nanorattles(GSNs)were easily prepared in a high yield by an improved seedmediated method employing polyvinylpyrrolidone(PVP) as a stabilizing and capping agent. The present method is very simple, effective and reproducible and can well control the growth process of gold nanoshells. The as-prepared GSNs have a narrow size distribution(<10 % in standard deviation). Furthermore, the utilization rate of Au in the solution used for the growth of gold nanoshells increases by 70 %than that in previous method. The resultant GSNs have a good structural stability after placing over 6 months due to the protection of PVP. More importantly, in vivo and in vitro toxic studies indicate that the GSNs have good biocompatibility. We believe that our preparation method will remarkably promote the use of gold nanoshells for biomedicine.Changhui Fu Chaofeng He Longfei Tan Shunhao Wang Lu Shang Linlin Li Xianwei Meng Huiyu Liu 2016Science Bulletin2016,61,4:5
12Simulations and Experimental Investigation on Motion Stability of a Flexible Rotor-bearing System with a Transverse Crack显示文摘In the classical process for stability studies on the rotor-bearing system with crack faults,the simple discrete model is adopted for research on such problems,which neglect some needful dynamical influence factor,such as the material damping,shearing effect and gyroscopic effects,etc.Therefore,it is necessary to find a precise calculation model for simulation of the rotor-bearing system with cracks faults.In this paper,instead of the traditional simple discrete model,finite element(FE)model is adopted to investigate the motion stability of a nonlinear rotor system with crack fault.According to finite element theory,the FE model of the cracked rotor system is established firstly.It should be pointed out that the element where the crack occurs is modeled by a particular crack element and the supports at both ends are simulated by two nonlinear loads.Then,based on dimensionless and dimensionality reduction,the Newmark-βmethod and the shooting method are employed to study the effect of eccentricity and the depth of crack on instability speed and bifurcation feature.Furthermore,the simulation results are verified by some corresponding experiments.The simulation and experimental results show that instability speed does not change monotonically,but decreases firstly and then increases when the amount of eccentricity increases.Moreover,as the type of instability changes,the instability speed jumps concomitantly.Additionally,the presence of crack fault can disturb the oil whirl,as a result,instability speed tends to increase slightly,but it does not affect the type of instability and jumping phenomenon.This research presents an effective and convenient method which uses the finite element method(FEM)to research the motion stability of the nonlinear rotor-bearing system with cracked faults and other nonlinear force,and the proposed method can provide a theoretical reference for stability analysis and vibration control in more complex relevant rotor-bearing system.LI Chaofeng YU Hexing ZHOU Shihua WEN Bangchun 2013Chinese Journal of Mechanical Engineering2013,26,6:5
13Constraints on the Ediacaran-Cambrian boundary in deep-water realm in South China: Evidence from zircon CA-ID-TIMS U-Pb ages from the topmost Liuchapo Formation显示文摘The placement of the Ediacaran-Cambrian boundary in deep-water realm in South China and the high-precision temporal framework for the Ediacaran-Cambrian transition in this region have not yet been completely solved. Recently, we have found two K-bentonite beds in the top of the Liuchapo Formation at the Pingyin section, Guizhou Province. It provides an opportunity for constructing the temporal framework of the transitional strata on the Yangtze Platform in South China and for determining the Ediacaran-Cambrian boundary in this area. In this study, we conducted high-precision CA-ID-TIMS U-Pb dating on zircons from the two K-bentonites. The ages of the two K-bentonites were precisely constrained at 536.40±0.47/1.1/1.2 Ma(2σ, n=7, MSWD=0.92) and 541.48±0.46/1.1/1.2 Ma(2σ, n=8, MSWD=1.3). Combining the geochronological results with organic carbon isotope data of chert in the topmost Liuchapo Formation from the section, we suggest that the EdiacaranCambrian boundary should be consistent with a significant negative organic carbon isotope excursion between the two Kbentonites. The scheme of the Ediacaran-Cambrian boundary in this study is of great significance for global correlation, and further for unravelling the information of the terminal Ediacaran-early Cambrian ocean.Wei WANG Mingzhong ZHOU Zhuyin CHU Junjie XU Chaofeng LI Taiyi LUO Jinghui GUO 2020Science China Earth Sciences2020,63,8:4
14Trachoma rapid assessment in Shandong province of China显示文摘Qu Yi Bi Hongsheng Wen Ying Li Chaofeng Wu Hui 2014Chinese Medical Journal2014,,14:3
15Towards a better recording of microtubule cytoskeletal spatial organization and dynamics in plant cells显示文摘Numerous fluorescent marker lines are currently available to visualize microtubule(MT)architecture and dynamics in living plant cells, such as markers expressing p35S::GFP-MBD or p35S::GFP-TUB6.However, these MT marker lines display obvious defects that affect plant growth or produce unstable fluorescent signals. Here, a series of new marker lines were developed, including the pTUB6::VisGreen-TUB6-expressing line in which TUB6 is under the control of its endogenous regulatory elements and e GFP is replaced with VisGreen, a brighter fluorescent protein. Moreover, two different markers were combined into one expression vector and developed two dual-marker lines.These marker lines produce bright, stable fluorescent signals in various tissues, and greatly shorten the screening process for generating dual-marker lines.These new marker lines provide a novel resource for MT research.Weiwei Liu Chaofeng Wang Guangda Wang Yinping Ma Juan Tian Yanjun Yu Li Dong Zhaosheng Kong 2019Journal of Integrative Plant Biology2019,61,4:3
16The enhanced photocatalytic sterilization of MOF-Based nanohybrid for rapid and portable therapy of bacteria-infected open wounds显示文摘Open wounds are prone to infection and difficult to heal,which even threatens the life of patients because bacterial infections can induce other lethal complications without prompt treatment.The commonly used antibiotics treatment for bacterial infections has been reported to cause globally bacterial resistance and even the occurrence of superbacteria.The highly effective and antibiotic-independent therapeutic strategies are urgently needed for treating various kinds of bacteria-infected diseases.In this work,we synthesized an eco-friendly nanohybrid material(ZnDMZ)consisting of a kind of biodegradable metal organic framework(MOF,ZIF-8)combined with Zn-doped MoS_(2)(Zn-MoS_(2))nanosheets,which exhibited great ability to kill bacteria and promote the healing of bacteria-infected wounds under 660 nm light irradiation.The underlying mechanism is that besides the local hyperthermia,the nanohybrid material exhibits enhanced photocatalytic performance than single component in it,i.e.,it can also be excited by 660 nm light to produce more oxygen radical species(ROS)due to the following factors.On one hand,the Zn doping can reduce the work function and the band gap of MoS_(2),which promotes the movement of photoexcited electrons to the surface of the material.On the other hand,the combination between Zn-MoS_(2) and MOF induces the formation of a built-in electric field due to their work function difference,thus accelerating the separation of photoexcited electron-hole pairs.Because of the synergy of photocatalytic effect,photothermal effect and the released Zn ions,the synthesized ZnDMZ possessed a highly effective antibacterial efficacy of 99.9%against Staphylococcus aureus under 660 nm light irradiation for 20 min without cytotoxicity.In vivo tests showed that this nanohybrid material promoted the wound healing due to the released Zn ions.This nanohybrid will be promising for rapid and portable treatment of bacteria-infected open wounds in pathogenic bacteria contaminated environments.Chaofeng Wang Yue Luo Xiangmei Liu Zhenduo Cui Yufeng Zheng Yanqin Liang Zhaoyang Li Shengli Zhu Jie Lei Xiaobo Feng Shuilin Wu 2022Bioactive Materials2022,7,7:3
17Identification of IFN-γ-producing innate B cells显示文摘Yan Bao Xingguang Liu Chaofeng Han Sheng Xu Bin Xie Qian Zhang Yan Gu Jin Hou Li Qian Cheng Qian Huanxing Han Xuetao Cao 2014Cell Research2014,24,2:3
18A comparison of summer precipitation structures over the South China Sea and the East China Sea based on tropical rainfall measurement mission显示文摘The three-dimensional structures of summer precipitation over the South China Sea(SCS)and the East China Sea(ECS)are investigated based on tropical rainfall measurement mission(TRMM).The primary results are as follows.First,both the convective and stratiform precipitation rates in the SCS are much higher than those of the ECS.The contribution of the convective cloud precipitation to the surface precipitation is primarily over the SCS and the ECS with a proportion of about 70%,but the contribution of convective cloud precipitation is slightly larger in the SCS than the ECS.The contribution of stratus precipitation is slightly larger in the ECS than that in the SCS.Second,the content of cloud particles and precipitation particles in the ECS in June was greater than that in the SCS,while in July and August,the content of cloud and precipitation particles in the ECS was less than that in the SCS.Third,the latent heat profile of the ECS is quite different from that of the SCS.In June,the peak values of evaporation and condensation latent heating rates in the ECS are greater than those in the SCS.In July and August,however,the peak values of evaporation and condensation latent heating rates in the ECS are about 0.05/h less than those in the SCS.LI Jiangnan YANG Chaofeng LI Fangzhou HE Qihua LI Weibiao 2013Acta Oceanologica Sinica2013,32,11:3
19High Precision Data-driven Force Control of Compact Elastic Module for a Lower Extremity Augmentation Device显示文摘Likun Wang Chaofeng Chen Zhengyang Li Wei Dong Zhijiang Du Yi Shen Guangyu Zhao 2018Journal of Bionic Engineering2018,15,5:3
20Vibrational characteristics of rotating soft cylinders显示文摘Rotating structural components are omnipresent in engineering structures and natural world. This work investigates the effects of the centrifugal and Coriolis forces on the free vibrational characteristics of soft cylinders rotating with respect to the axis of symmetry based on the nonlinear elasticity and linear incremental theories. The formulations indicate that the biasing deformation, instantaneous elastic moduli, and incremental equations of motion strongly depend on the rotating speed. The characteristic equation for the natural frequency is derived using the state-space method and approximate laminate technique.The numerical examples included in this work demonstrate that the centrifugal and Coriolis forces might have significant effects on the vibrational characteristics of the cylinder. Results of this work will benefit the design and control of novel engineering systems with rotating soft cylinders or shafts.Kecheng Li Yinnan Zhang Haifei Zhan Yangkun Du Chaofeng Li 2021Science China(Physics,Mechanics & Astronomy)2021,64,5:2
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