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| 1 | Characteristics of Long Air Gap Discharge Current Subjected to Switching Impulse显示文摘Measuring the pre-breakdown current of long sparks in air is important for investigating the discharge mechanism.Since the breakdown of long air gaps is conducted by a series of streamer-leader processes,the corresponding current signals cover a bandwidth of 0 to more than 20 MHz.Measurement accuracy of the current from the high voltage side is affected by the displacement current and impulse electromagnetic interference.In this paper,a coaxial current sensor with a DC bandwidth of 74.45 MHz is developed.A displacement current-restrained electrode structure is proposed to reduce the equivalent capacitance between the current sensor and the ground over 30 times.Combined with the digital optical fiber synchronous acquisition unit,a current measurement system for long air gap discharge is established.For the purpose of the UHV system’s external insulation optimization design,the discharge current waveform of a 6 m rod-plane air gap under positive switching impulse voltage with 250µs and 1000µs time to crest is obtained.Discharge images and stressed voltage are combined to analyze the continuous feature of a current waveform under critical time to crest impulse and discontinuous feature under long front duration impulse.For the purposes of a lightning protection study,the current waveform of a 10 m rod-plane air gap is subjected to negative switching impulse.Finally,the pulse characteristics of the current corresponding to the single channel and branching stepped negative leader are discussed. | Yishi Yue Hengxin He Weijiang Chen Junjia He Chuanqi Wu Xiangen Zhao Feng Huo | 2015 | CSEE Journal of Power and Energy Systems2015，1，3： | 13 |
| 2 | Environmental impact and health risk assessment of volatile organic compound emissions during different seasons in Beijing显示文摘Volatile organic compounds(VOCs)are major contributors to air pollution.Based on the emission characteristics of 99 VOCs that daily measured at 10 am in winter from 15 December 2015 to 17 January 2016 and in summer from 21 July to 25 August 2016 in Beijing,the environmental impact and health risk of VOC were assessed.In the winter polluted days,the secondary organic aerosol formation potential(SOAP)of VOC(199.70±15.05 mg/m^3)was significantly higher than that on other days.And aromatics were the primary contributor(98.03%)to the SOAP during the observation period.Additionally,the result of the ozone formation potential(OFP)showed that ethylene contributed the most to OFP in winter(26.00%and 27.64%on the normal and polluted days).In summer,however,acetaldehyde was the primary contributor to OFP(22.00%and 21.61%on the normal and polluted days).Simultaneously,study showed that hazard ratios and lifetime cancer risk values of acrolein,chloroform,benzene,1,2-dichloroethane,acetaldehyde and 1,3-butadiene exceeded the thresholds established by USEPA,thereby presenting a health risk to the residents.Besides,the ratio of toluene-to-benzene indicated that vehicle exhausts were the main source of VOC pollution in Beijing.The ratio of m-/p-xylene-toethylbenzene demonstrated that there were more prominent atmospheric photochemical reactions in summer than that in winter.Finally,according to the potential source contribution function(PSCF)results,compared with local pollution sources,the spread of pollution from long-distance VOCs had a greater impact on Beijing. | Chuanqi Li Qianqian Li Dongge Tong Qingliang Wang Mingge Wu Bohua Sun Guijin Su Li Tan | 2020 | Journal of Environmental Sciences2020，32，7： | 10 |
| 3 | Predicting TBM penetration rate in hard rock condition:A comparative study among six XGB-based metaheuristic techniques显示文摘A reliable and accurate prediction of the tunnel boring machine(TBM)performance can assist in minimizing the relevant risks of high capital costs and in scheduling tunneling projects.This research aims to develop six hybrid models of extreme gradient boosting(XGB)which are optimized by gray wolf optimization(GWO),particle swarm optimization(PSO),social spider optimization(SSO),sine cosine algorithm(SCA),multi verse optimization(MVO)and moth flame optimization(MFO),for estimation of the TBM penetration rate(PR).To do this,a comprehensive database with 1286 data samples was established where seven parameters including the rock quality designation,the rock mass rating,Brazilian tensile strength(BTS),rock mass weathering,the uniaxial compressive strength(UCS),revolution per minute and trust force per cutter(TFC),were set as inputs and TBM PR was selected as model output.Together with the mentioned six hybrid models,four single models i.e.,artificial neural network,random forest regression,XGB and support vector regression were also built to estimate TBM PR for comparison purposes.These models were designed conducting several parametric studies on their most important parameters and then,their performance capacities were assessed through the use of root mean square error,coefficient of determination,mean absolute percentage error,and a10-index.Results of this study confirmed that the best predictive model of PR goes to the PSO-XGB technique with system error of(0.1453,and 0.1325),R^(2) of(0.951,and 0.951),mean absolute percentage error(4.0689,and 3.8115),and a10-index of(0.9348,and 0.9496)in training and testing phases,respectively.The developed hybrid PSO-XGB can be introduced as an accurate,powerful and applicable technique in the field of TBM performance prediction.By conducting sensitivity analysis,it was found that UCS,BTS and TFC have the deepest impacts on the TBM PR. | Jian Zhou Yingui Qiu Danial Jahed Armaghani Wengang Zhang Chuanqi Li Shuangli Zhu Reza Tarinejad | 2021 | Geoscience Frontiers2021，12，3： | 10 |
| 4 | Hydrothermal Synthesis of Molybdenum Disulfide for Lithium Ion Battery Applications显示文摘Molybdenum disulfide nanoflakes were synthesized by a simple hydrothermal process using sodium molybdate and thiourea as reactants at a relatively low temperature. X-ray diffraction(XRD) and transmission elec-tron microscopy(TEM) indicate that the samples have the structure of 2H-MoS2 and the morphology of nanoflakes with the average thickness around 5-10 nm. The results of electrochemical properties indicate that the morphology and size of MoS2 particles have effects on their capacity when they are used as the anode for lithium ion battery. The as-prepared MoS2 samples have high reversible discharge capacity up to 994.6 mA·h·g-1 for the MoS2-1 elec-trode and 930.1 mA·h·g-1 for the MoS2-2 electrode and show excellent cycling performances. The MoS2-1 electrode has a better cycling stability than the MoS2-2 electrode due to their difference in the uniformity of the samples. | WANG Shiquan LI Guohua DU Guodong JIANG Xueya FENG Chuanqi GUO Zaiping KIM Seung-Joo | 2010 | Chinese Journal of Chemical Engineering2010，18，6： | 9 |
| 5 | Asynchronous Brain-Computer Interface Shared Control of Robotic Grasping显示文摘The control of a high Degree of Freedom(DoF) robot to grasp a target in three-dimensional space using Brain-Computer Interface(BCI) remains a very difficult problem to solve. Design of synchronous BCI requires the user perform the brain activity task all the time according to the predefined paradigm; such a process is boring and fatiguing. Furthermore, the strategy of switching between robotic auto-control and BCI control is not very reliable because the accuracy of Motor Imagery(MI) pattern recognition rarely reaches 100%. In this paper, an asynchronous BCI shared control method is proposed for the high DoF robotic grasping task. The proposed method combines BCI control and automatic robotic control to simultaneously consider the robotic vision feedback and revise the unreasonable control commands. The user can easily mentally control the system and is only required to intervene and send brain commands to the automatic control system at the appropriate time according to the experience of the user. Two experiments are designed to validate our method: one aims to illustrate the accuracy of MI pattern recognition of our asynchronous BCI system; the other is the online practical experiment that controls the robot to grasp a target while avoiding an obstacle using the asynchronous BCI shared control method that can improve the safety and robustness of our system. | Wenchang Zhang Fuchun Sun Hang Wu Chuanqi Tan Yuzhen Ma | 2019 | Tsinghua Science and Technology2019，24，3： | 8 |
| 6 | SnS_2@C Hollow Nanospheres with Robust Structural Stability as High?Performance Anodes for Sodium Ion Batteries显示文摘Constructing unique and highly stable structures with plenty of electroactive sites in sodium storage materials is a key factor for achieving improved electrochemical properties through favorable sodium ion di usion kinetics. An SnS_2@carbon hollow nanospheres(SnS_2@C) has been designed and fabricated via a facile solvothermal route, followed by an annealing treatment. The SnS_2@C hybrid possesses an ideal hollow structure, rich active sites, a large electrode/electrolyte interface, a shortened ion transport pathway, and, importantly, a bu er space for volume change, generated from the repeated insertion/extraction of sodium ions. These merits lead to the significant reinforcement of structural integrity during electrochemical reactions and the improvement in sodium storage properties, with a high specific reversible capacity of 626.8 mAh g^(-1) after 200 cycles at a current density of 0.2 A g^(-1) and superior high-rate performance(304.4 mAh g^(-1) at 5 A g^(-1)). | Shuaihui Li Zhipeng Zhao Chuanqi Li Zhongyi Liu Dan Li | 2019 | Nano-Micro Letters2019，11，1： | 8 |
| 7 | Fracture analysis of rock mass based on 3-D nonlinear Finite Element Method显示文摘Traditional fracture analysis is based on fracture mechanics and damage mechanics. They focus on the propagation of the fracture. However, their propagation criterions are not easily applied in practice and the current analysis is limited in planar problem. This paper presents a new theory that the occurrence of the unbalanced force (derived from the Deformation Reinforcement Theory) could be the criterion of the initiation of the fracture, and the distribution area and propagation of the unbalanced force could be the indication of the fracture propagation direction. By aggregate analysis with Stress Intensity Factor (SIF) criterion, the unbalanced force actually is the opposite external load that is the SIF difference incurred between the external loads and permitted by the structure. Numerical simulation and physical experiments on pre-fracture cuboid rock specimens proved that the occurrence of the unbalanced force could be the initiation of the fracture. Mesh size dependence was also considered by analysis of different mesh size finite element gravity dam models. Furthermore, the theory was applied to the feasibility analysis of the Baihetan arch dam together with physical experiments in order to evaluate the fracture propagation of dam heel. The results show that it is an effective way to use unbalanced force to analyze the fracture initiation and propagation when performing 3-dimensional nonlinear FEM calculation. | LIU YaoRu CHANG Qiang YANG Qiang WANG ChuanQi GUAN FuHai | 2011 | Science China(Technological Sciences)2011，54，3： | 8 |
| 8 | Non‑noble Metal Electrocatalysts for the Hydrogen Evolution Reaction in Water Electrolysis显示文摘Water electrolysis is a sustainable approach for hydrogen production by using electricity from clean energy sources.However,both the hydrogen evolution reaction(HER)and the oxygen evolution reaction(OER)associated with water electrolysis are kinetically sluggish,leading to low efficiency in corresponding electrolysis devices.In addition,current electrocatalysts that can catalyze both HER and OER to practical rates require noble metals such as platinum that are low in abundance and high in price,severely limiting commercialization.As a result,the development of high-performance and cost-effective non-noble metal electrocatalysts to replace noble ones has intensified.Based on this,this review will comprehensively present recent research in the design,synthesis,characterization and performance validation/optimization of non-noble metal HER electrocatalysts and analyze corresponding catalytic mechanisms.Moreover,several important types of non-noble metal electrocatalysts including zero-dimensional,one-dimensional,two-dimensional and three-dimensional materials are presented with an emphasis on morphology/structure,synergetic interaction between metal and support,catalytic property and HER activity/stability.Furthermore,existing technical challenges are summarized and corresponding research directions are proposed toward practical application. | Huimin Wu Chuanqi Feng Lei Zhang Jiujun Zhang David P.Wilkinson | 2021 | Electrochemical Energy Reviews2021，4，3： | 7 |
| 9 | A review of EEG-based brain-computer interface systems design显示文摘A brain-computer interface(BCI) system can recognize the mental activities pattern by computer algorithms to control the external devices. Electroencephalogram(EEG) is one of the most common used approach for BCI due to the convenience and non-invasive implement. Therefore, more and more BCIs have been designed for the disabled people that suffer from stroke or spinal cord injury to help them for rehabilitation and life. We introduce the common BCI paradigms, the signal processing, and feature extraction methods. Then, we survey the different combined modes of hybrids BCIs and review the design of the synchronous/asynchronous BCIs.Finally, the shared control methods are discussed. | Wenchang Zhang Chuanqi Tan Fuchun Sun Hang Wu Bo Zhang | 2018 | Translational Neuroscience and Clinics2018，4，2： | 5 |
| 10 | A Robust Gaussian Mixture Model for Mobile Robots’ Vision-based Pose Estimation显示文摘In dynamic environments, the moving landmarks can make the accuracy of traditional vision-based pose estimation worse or even failure. To solve this problem, a robust Gaussian mixture model for vision-based pose estimation is proposed. The motion index is added to the traditional graph-based vision-based pose estimation model to describe landmarks’ moving probability, transforming the classic Gaussian model to Gaussian mixture model, which can reduce the influence of moving landmarks for optimization results. To improve the algorithm’s robustness to noise, the covariance inflation model is employed in residual equations. The expectation maximization method for solving the Gaussian mixture problem is derived in detail, transforming the problem into classic iterative least square problem. Experimental results demonstrate that in dynamic environments, the proposed method outperforms the traditional method both in absolute accuracy and relative accuracy, while maintains high accuracy in static environments. The proposed method can effectively reduce the influence of the moving landmarks in dynamic environments, which is more suitable for the autonomous localization of mobile robots. | Chuanqi CHENG Xiangyang HAO Jiansheng LI Peng HU Xu ZHANG | 2019 | Journal of Geodesy and Geoinformation Science2019，2，3： | 4 |
| 11 | NATIONAL KNOWLEDGE INNOVATION SYSTEMS: EVOLUTION, DEFINITION AND INDICATORS显示文摘The paper examines the three stages of the evolution of national innovation systems: national technology innovation systems, national innovation systems and national knowledge innovation systems. A national knowledge innovation system is a network of institutions and organizations which jointly or individually contributes to the knowledge innovation (including scientific and technical knowledge innovation). The author stresses that knowledge innovation will occur in all processes of the produc-tion, transmission and use of knowledge. There are four subsystems in this system: scientific knowledge innovation, technical knowledge innovation, knowledge trans-mission and knowledge use subsystem. The author also lists some indicators for the System. | He Chuanqi (Bureau of Planning and Finance, the CAS) | 1999 | Bulletin of the Chinese Academy of Sciences1999，13，4： | 3 |
| 12 | Targeting orthotopic gliomas with renal-clearable luminescent gold nanoparticles显示文摘在 nanomedicine 的主要临床的翻译挑战是在主要机关与举起和非可能减解的 nanoparticles (NP ) 的长期的保留联系的毒性的潜力。经历肾的清理的无机的 NP 的发展能潜在地解决这颗重要 biosafety 担心。然而,能被肾排泄的无机的 NP 是否仍然保持能够与差的渗透指向肿瘤,仍然保持不清楚。Glioblastoma multiforme,最恶意的 orthotopic 大脑肿瘤,因为血大脑障碍和反应 microglia 和 macroglia 的柔韧的血肿瘤障碍,在肿瘤微型环境为 NP 交货提出唯一的挑战。此处,我们使用了 orthotopic 调查在直径的 3 nm 的谷胱甘肽涂的金 nanoparticles (AuNPs ) 的被动指向的鼠科的 glioma 模型经历没能经历肾的清理的肾的清理和 18-nm AuNPs。显著地,我们报导 3-nm AuNPs 能与更高的效率指向 intracranial 肿瘤纸巾(2.3ver 在 1.0 妈骑车的 100 | Chuanqi Peng Xiaofei Gao Jing Xu Bujie Du Xuhui Ning Shaoheng Tang Robert M. Bachoo Mengxiao Yu Woo-Ping Ge Jie Zheng | 2017 | Nano Research2017，10，4： | 3 |
| 13 | HSM-based Change Object-Oriented Impact Analysis of Java Programs显示文摘 | SUN Xiaobing LI Bixin TAO Chuanqi ZHANG Sai | 2011 | Chinese Journal of Electronics2011，20，2： | 3 |
| 14 | Palladium(Ⅱ)-Catalyzed Aminotrifluoromethoxylation of Alkenes:Mechanistic Insight into the Effect of N-Protecting Groups显示文摘Summary of main observation and conclusion An eficient palladium-atalyzed regioselective 5 exo aminotrifluoromethoxylation of alkenes has been established herein,which provides practical route towards the synthesis of OCF g-containing prrolidines.tert-Butyloxycarbonyl(Boc)as an amino pro-tecting group plays a signifiant role in both the chemo-and regloselectivities.In addition,preliminary mechanistic studies reveal that the amino protect-ing group of substrates and the counter anion of palladium catalyst play critical roles in reaction efficiency presumably due to an isomerization of alkyl-Pd(Ⅱ)intermediates.Moreover,the asymmetric 5-exo aminrifluoromethoxylation reaction has also been achieved by introducing a serelallyl bulky pyri-dinyl-oxazoline ligand. | Chaohuang Chen Chuanqi Hou Pinhong Chen Guosheng Liu | 2020 | Chinese Journal of Chemistry2020，38，4： | 3 |
| 15 | A glove-based system for object recognition via visual-tactile fusion显示文摘Dear editor,In our daily life,information such as tactile and visual information is widely used to recognize objects when we manipulate them.Research has shown that the human brain makes use of multisensory models of objects(1)However,the issue of how to combine visual and tactile information for classification. | Bin FANG Fuchun SUN Huaping LIU Chuanqi TAN Di GUO | 2019 | Science China(Information Sciences)2019，62，5： | 2 |
| 16 | Stability analysis of soil slope based on deformation reinforcement theory显示文摘 | Yaoru Liu Chuanqi Wang Qiang Yang | 2012 | Finite Elements in Analysis & Design2012，，： | 2 |
| 17 | Hydrothermal treatment of metallic-monolith catalyst support with self-growing porous anodic-alumina film显示文摘Metallic-monolith catalyst support with self-growing porous anodic alumina(PAA)film was prepared by anodizing Al plate.The effect of hydrothermal treatment(HTT)on the crystalline state and textural properties of PAA film was investigated by XRD,BET,SEM and TG.The HTT treatment above 50°C and the subsequent calcination above 300°C could convert the amorphous skeleton alumina intoγ-alumina and increase the specific surface area(SBET).However,SEM images showed the HTT modification was a non-uniform process along the thickness of PAA film.The promotion effect of HTT on SBETwas non-linear,and the slope of SBETgradually decreased with the HTT temperature or time increased.The limited HTT effect should be attributed to a changed pore structure caused by an unfavorable pore sealing limitation.Pore widening treatment(PWT)before HTT could break the pore sealing limitation,because of the reduced internal diffusion resistance of hydrothermal reaction.The synergistic combination of PWT and HTT developed a PAA support with a large SBETcomparable to commercialγ-alumina.In the catalytic combustion of toluene,the Pt-based catalyst prepared by using the PWT and HTT comodified PAA support gave higher Pt dispersion and more favorable catalytic activity than that treated by HTT alone.The presence of a bimodal pore structure was suggested to be a decisive reason. | Chuanqi Zhang Yuanjing Pu Feng Wang Hecheng Ren Hua Ma Yu Guo | 2020 | Chinese Journal of Chemical Engineering2020，28，5： | 2 |
| 18 | Predicting the Thickness of an Excavation Damaged Zone around the Roadway Using the DA-RF Hybrid Model显示文摘After the excavation of the roadway,the original stress balance is destroyed,resulting in the redistribution of stress and the formation of an excavation damaged zone(EDZ)around the roadway.The thickness of EDZ is the key basis for roadway stability discrimination and support structure design,and it is of great engineering significance to accurately predict the thickness of EDZ.Considering the advantages of machine learning(ML)in dealing with high-dimensional,nonlinear problems,a hybrid prediction model based on the random forest(RF)algorithm is developed in this paper.The model used the dragonfly algorithm(DA)to optimize two hyperparameters in RF,namely mtry and ntree,and used mean absolute error(MAE),rootmean square error(RMSE),determination coefficient(R^(2)),and variance accounted for(VAF)to evaluatemodel prediction performance.A database containing 217 sets of data was collected,with embedding depth(ED),drift span(DS),surrounding rock mass strength(RMS),joint index(JI)as input variables,and the excavation damaged zone thickness(EDZT)as output variable.In addition,four classic models,back propagation neural network(BPNN),extreme learning machine(ELM),radial basis function network(RBF),and RF were compared with the DA-RF model.The results showed that the DARF mold had the best prediction performance(training set:MAE=0.1036,RMSE=0.1514,R^(2)=0.9577,VAF=94.2645;test set:MAE=0.1115,RMSE=0.1417,R^(2)=0.9423,VAF=94.0836).The results of the sensitivity analysis showed that the relative importance of each input variable was DS,ED,RMS,and JI from low to high. | Yuxin Chen Weixun Yong Chuanqi Li Jian Zhou | 2023 | Computer Modeling in Engineering & Sciences2023，，9： | 2 |
| 19 | Structural whiteness of the multi-component glaze dependence on amorphous photonic crystals显示文摘A kind of enhancing mechanism of structural whiteness dependence on amorphous photonic crystal (APC) structure is introduced in this paper. In the glaze system composed of albite, kaolin, talc, calcite, quartz, titanium dioxide and zinc oxide, the APC structure will be produced by using quartz as a variable to induce the phase separation. Under different polarities between Ti, Zn etc. and Siion, the separated spheres with the core-shell structure can be obtained and then make up opal-like APCs in the glaze layer. In addition to inner and outer layers of core-shell spheres, the calculated results of refractive indices clearly show the great difference between the particles and the matrix. As a result of different refractive indices, the multiple scatting of visible light plays a key rote in the structural whiteness. However, due to the decrease of the cationic content, APCs with the reverse opal structure would be formed in the interface between glaze and body. Ultimately, the glaze appearance reveals extremely high structural whiteness due to the special APC structure. | Hongquan ZHAN Chuanqi WU Ce DENG Xiaohong LI Zhipeng XIE Changan WANG | 2019 | Frontiers of Materials Science2019，13，2： | 2 |
| 20 | Plasma transport between the ionosphere and plasmasphere in response to solar wind dynamic pressure pulsation显示文摘The plasma transport between the plasmasphere and the ionosphere in response to the interplanetary conditions is still not fully understood until now.Simultaneous observations of the plasmasphere and ionosphere from the newly developed Chinese Meridian Project provide a new opportunity for understanding the characteristic of the plasma transport and the coupling mechanism between these two regions.We investigate the response of the plasmasphere(L≈2)and ionosphere to the solar wind dynamic pressure pulse during geomagnetically quiet period of 21–27 March 2011.The response of the plasmasphere shows a significant depletion.The plasmaspheric density nearly decreases by half in response to the solar wind dynamic pressure pulse,and subsequently recovers to the original level in 1–2 d.Meanwhile,the maximum electron density of the ionospheric F2 layer(NmF2)and the total electron content(TEC)increase by 13%and 21%,respectively,and then gradually recover,which is opposite to the behavior during magnetic storms.Preliminary analysis shows that the plasmaspheric depletion may be mainly caused by the southward interplanetary magnetic field and changing dawn-dusk electric field.The plasmaspheric density variations seem to be controlled by both the IMF and ionospheric conditions. | ZHANG QingMei WANG Chi LI Hui LI ChuanQi | 2013 | Chinese Science Bulletin2013，58，33： | 2 |
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