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| 1 | A chlorinated copolymer donor demonstrates a 18.13% power conversion efficiency显示文摘The rapid development of low-bandgap(LBG)nonfullerene acceptors and wide-bandgap(WBG)copolymer donors in recent years has boosted the power conversion efficiency(PCE)of organic solar cells(OSCs)to the 18%level[1−21].The commercialization of OSCs is highly expected.However,critical issues like the cost and the stability also determine whether OSCs can enter the market or not[22]. | Jianqiang Qin Lixiu Zhang Chuantian Zuo Zuo Xiao Yongbo Yuan Shangfeng Yang Feng Hao Ming Cheng Kuan Sun Qinye Bao Zhengyang Bin Zhiwen Jin and Liming Ding | 2021 | Journal of Semiconductors2021，42，1： | 19 |
| 2 | Experimental research on electrochemical machining of titanium alloy Ti60 for a blisk显示文摘Ti60(Ti–5.6Al–4.8Sn–2Zr–1Mo–0.35Si–0.7Nd) is a high-temperature titanium alloy that is now used for important components of aircraft engines. Electrochemical machining(ECM) is a promising technique that has several advantages, such as a high machining rate, and can be used on a wide range of difficult-to-process materials. In this paper, orthogonal experiments are conducted to investigate ECM of Ti60, with the aim of determining the influences of some electrochemical process parameters on the surface roughness. The most important parameter is found to be the frequency of the pulsed power supply. It is found that using suitably optimized parameters for ECM can greatly decrease the surface roughness of a workpiece. A surface roughness of approximately 0.912 lm can be obtained with the following optimal parameters: Na Cl electrolyte concentration 13wt%, voltage20 V, pulse frequency 0.4 k Hz, duty cycle 0.3, temperature 23 °C, and anode feed rate 0.5 mm/min.Furthermore, blisk blades have been successfully processed using these optimized parameters. | Chen Xuezhen Xu Zhengyang Zhu Dong Fang Zhongdong Zhu Di | 2016 | Chinese Journal of Aeronautics2016，29，1： | 17 |
| 3 | Trajectory control strategy of cathodes in blisk electrochemical machining显示文摘A turbine blisk, which combines blades and a disk together, is one of the most important components of an aero engine. In the process of blisk electrochemical machining (ECM), the sheet cathode, which is usually used as a tool electrode, has a complicated structure. In addition to that, the channel between the adjacent blades is narrow and twisted, so interference is apt to happen when the sheet cathode feeds into the channel. Therefore, it is important to choose suitable trajectory control strategy. In this paper, a new trajectory control strategy of the sheet cathode is presented and corresponding simulation analysis is conducted on the basis of an actual blisk model. The simulation results demonstrate that the sheet cathode can feed into the channel by a spatial line trajectory without interference. Moreover, the verification experiments are carried out according to the simulation. The experimental results show that the cathode can move into the channel without interference. It is verified that the new trajectory control strategy is correct and can be used in the blisk ECM process successfully. | Zhu Dong Zhu Di Xu Zhengyang Zhou Laishui | 2013 | Chinese Journal of Aeronautics2013，26，4： | 14 |
| 4 | Spatial dynamics of aboveground carbon stock in urban green space:a case study of Xi'an,China显示文摘Greenhouse gas emission of carbon dioxide(CO2) is one of the major factors causing global climate change.Urban green space plays a key role in regulating the global carbon cycle and reducing atmospheric CO2.Quantifying the carbon stock,distribution and change of urban green space is vital to understanding the role of urban green space in the urban environment.Remote sensing is a valuable and effective tool for monitoring and estimating aboveground carbon(AGC) stock in large areas.In the present study,different remotely-sensed vegetation indices(VIs) were used to develop a regression equation between VI and AGC stock of urban green space,and the best fit model was then used to estimate the AGC stock of urban green space within the beltways of Xi'an city for the years 2004 and 2010.A map of changes in the spatial distribution patterns of AGC stock was plotted and the possible causes of these changes were analyzed.Results showed that Normalized Difference Vegetation Index(NDVI) correlated moderately well with AGC stock in urban green space.The Difference Vegetation Index(DVI),Ratio Vegetation Index(RVI),Soil Adjusted Vegetation Index(SAVI),Modified Soil Adjusted Vegetation Index(MSAVI) and Renormalized Difference Vegetative Index(RDVI) were lower correlation coefficients than NDVI.The AGC stock in the urban green space of Xi'an in 2004 and 2010 was 73,843 and 126,621 t,respectively,with an average annual growth of 8,796 t and an average annual growth rate of 11.9%.The carbon densities in 2004 and 2010 were 1.62 and 2.77 t/hm2,respectively.Precipitation was not an important factor to influence the changes of AGC stock in the urban green space of Xi'an.Policy orientation,major ecological greening projects such as 'transplanting big trees into the city' and the World Horticultural Exposition were found to have an important impact on changes in the spatiotemporal patterns of AGC stock. | ZhengYang YAO JianJun LIU XiaoWen ZHAO DongFeng LONG Li WANG | 2015 | Journal of Arid Land2015，7，3： | 13 |
| 5 | Electrochemical machining of complex components of aero-engines: Developments, trends, and technological advances显示文摘Because of several advantages, such as no tool wear, independence on the mechanical properties of the material, and high machining efficiency, electrochemical machining(ECM) has become a viable method for machining components in numerous industrial applications, particularly in the manufacture of typical aero-engine components with complex structures fabricated from materials that are difficult to cut. This paper highlights the current developments, new trends, and technological advances of key factors of ECM, such as electrochemical dissolution characteristics of novel difficult to cut materials which are often used in aero-engine, numerical simulation of electrochemical process, design for the complex profile and structure of cathode tool, flow field simulation and design for uniform electrolyte flow, and innovation of electrochemical machining or hybrid methods which reflect the state of the art in academic and industrial research on electrochemical machining in aero-engine manufacturing. | Zhengyang XU Yudi WANG | 2021 | Chinese Journal of Aeronautics2021，34，2： | 13 |
| 6 | Three-dimensional experimental study of loose top-coal drawing law for longwall top-coal caving mining technology显示文摘Based on the loose medium flow field theory, the loose top-coal drawing law of longwall top-coal caving(LTCC) mining technology is studied by using self-developed three-dimensional(3D) test device. The loose top-coal drawing test with shields and the controlled test without shields are performed in the condition without any boundary effect. Test results show that shields will cause reduction in drawing volume of coal in the LTCC mining. The deflection phenomenon of drawing body is also observed in the controlled test, which is verified that the deflection of drawing body is caused by shield. It is found that the deflection angle decreases with increasing caving height, with the maximum value of atailand the minimum value of 0. In addition, the formula to calculate the drawing volume is proposed subsequently.The deflection of drawing body is numerically simulated using particle flow code PFC3 Dand the proposed formula to calculate drawing volume in LTCC is also verified. | Jiachen Wang Jinwang Zhang Zhengyang Song Zhaolong Li | 2015 | Journal of Rock Mechanics and Geotechnical Engineering2015，7，3： | 12 |
| 7 | Porous nitrogen-doped carbon/MnO coaxial nanotubes as an efficient sulfur host for lithium sulfur batteries显示文摘As a promising candidate for next generation energy storage devices, lithium sulfur (Li-S) batteries still confrant rapid capacity degradation and low rate capability. Herein, we report a well-architected porous nitrogen-doped carbon/MnO coaxial nanotubes (MnO@PNC) as an efficient sulfur host material. The host shows excellent electron conductivity, sufficient ion transport channels and strong adsorption capability for the polysulfides, resulting from the abundant nitrogen-doped sites and pores as well as MnO in the carbon shell of MnO@PNC. The MnO@PNC-S composite electrode with a sulfur content of 75 wt.% deliveries a specific capacity of 802 mAh·g^-1 at a high rate of 5.0C and outstanding cycling stability with a capacity retention of 82% after 520 cycles at 1.0C. | Chao Lin Longbing Qu Jiantao Li Zhengyang Cai Haoyun Liu Pan He Xu Xu Liqiang Mai | 2019 | Nano Research2019，12，1： | 10 |
| 8 | Electrochemical performance of Ti_(3)C_(2)supercapacitors in KOH electrolyte显示文摘Two-dimensional(2D)carbide Ti_(3)C_(2)was synthesized by exfoliating Ti_(3)AlC_(2)in HF solution and used for supercapacitive performance investigation in 3 M KOH electrolyte.The specific surface area(SSA)of as-synthesized Ti_(3)C_(2)was 22.35 m^(2)/g.Ti_(3)C_(2)-based supercapacitor electrodes exhibited good energy storage ability and had a volumetric capacitance 119.8 F/cm^(3)at the current density of 2.5 A/g.Moreover,the addition of carbon black into Ti_(3)C_(2)powders greatly improved the performance of Ti_(3)C_(2)-based capacitors because carbon black restrained the preferred orientation of 2D Ti_(3)C_(2),providing fast ion transport channels,and in turn,decreasing electrical resistance from 16.7Ωto 3.5Ω. | Yupeng GAO Libo WANG Zhengyang LI Yafei ZHANG Baolin XING Chuanxiang ZHANG Aiguo ZHOU | 2015 | Journal of Advanced Ceramics2015，4，2： | 10 |
| 9 | Machining of a film-cooling hole in a single-crystal superalloy by high-speed electrochemical discharge drilling显示文摘Single-crystal superalloys are typical advanced materials used for manufacturing aeroengine turbine blades. Their unique characteristics of high hardness and strength make them exceedingly difficult to machine. However, a key structure of a turbine blade, the film-cooling hole,needs to be machined in a single-crystal superalloy; such machining is challenging, especially considering the increasing levels of machining efficiency and quality demanded by the aeroengine industry. Tube electrode high-speed electrochemical discharge drilling(TSECDD), a hybrid technique of high-speed electrical discharge drilling and electrochemical machining, provides high machining efficiency and accuracy, as well as eliminating the recast layer. In this study, TSECDD is used to machine a film-cooling hole in a nickel-based single-crystal superalloy(DD6). The Taguchi methods of experiment are used to optimise the machining parameters. Experimental results show that TSECDD can effectively drill the film-cooling hole; the optimum parameters that give the best performance are as follows: pulse duration: 12 ls, pulse interval: 30 ls, peak current:6 A, and salt solution conductivity: 3 m S/cm. Finally, a hole is machined by TSECDD, and the results are compared with those obtained by electrical discharge machining. TSECDD is found to be promising for improving the surface quality and eliminating the recast layer. | Zhang Yan Xu Zhengyang Zhu Yun Zhu Di | 2016 | Chinese Journal of Aeronautics2016，29，2： | 10 |
| 10 | Controlled release and biocompatibility of polymer/titania nanotube array system on titanium implants显示文摘Bacterial infection and tissue inflammation are the major causes of early failure of titanium-based orthopedic implants;thus,surgical implants with tunable drug releasing properties represent an appealing way to address some of these problems of bacterial infection and tissue inflammation in early age of orthopedic implants.In this work,a hybrid surface system composed of biodegradable poly(lactic-coglycolic acid)(PLGA)and titania nanotubes(TNTs)has been successfully constructed on Ti implants with the aim of preventing bacterial infection via long-term drug release.By varying the size of the TNTs and the thickness of the polymer film,the drug release profile can be tuned to achieve the optimal therapeutic action throughout the treatment time.The size of TNTs plays a dominant role in the drug loading dose of TNTs/PLGA hybrid coatings.In this work,TNTs with an average size of 80 nm can achieve the largest loading dose.Depending on the polymer thickness,significant improvement in the drug release characteristics is attained,for instance,reduced burst release(from 84%to 27%)and overall release time extended from 5 to over 40 days.In addition,the PLGA layers may favor the proliferation and osteogenesis of MC3T3-E1 mouse cells at an earlier stage.Therefore,this TNT/PLGA hybrid surface system can be employed as an effective bioplatform for improving both self-antibacterial performance and biocompatibility of Ti-based biomaterials. | Tingting Wang Zhengyang Weng Xiangmei Liu Kelvin W.K.Yeung Haobo Pan Shuilin Wu | 2017 | Bioactive Materials2017，2，1： | 8 |
| 11 | Heat Transfer Characteristics of Boiler Convective Heating Surface Under Pressurized Oxygen-fuel Combustion Conditions显示文摘增压富氧燃烧是一项极具前景的减排CO2新技术。对增压富氧燃烧条件下,对流受热面换热特性进行研究具有重要的意义。该文以一台实际300MW等级机组煤粉锅炉为计算对象,采用维里方程及Chun等的计算方法计算确定增压富氧燃烧烟气物性,采用宽带关联k模型计算富氧燃烧烟气辐射特性。进行了常规空气燃烧以及φ(O2):φ(CO2)=21:79、φ(O2):φ(CO2)=30:70两种比例的0.1、0.5、1.0、1.5、6 MPa五种压力下增压富氧燃烧各对流受热面的热力计算,分析了增压富氧燃烧条件烟气压力变化对各受热面换热特性的影响。研究结果表明:随烟气压力的升高,烟气流速下降,但烟气的Re却基本保持不变,对流换热系数有所增加。增压富氧燃烧烟气的辐射换热系数比空气燃烧烟气辐射换热系数大。实现同样的换热量,增压富氧燃烧条件下(φ(O2):φ(CO2)=21:79、φ(O2):φ(CO2)=30:70)对流受热面所需换热面积比常规空气燃烧条件下少。 | Gao Zhengyang Xia Ruiqing Yan Weiping Ma Kai Feng Wenhui Zhang Bowen | 2012 | 中国电机工程学报2012，32，23： | 8 |
| 12 | Confined van der Waals Epitaxial Growth of Two-Dimensional Large Single-Crystal In_(2)Se_(3) for Flexible Broadband Photodetectors显示文摘The controllable growth of two-dimensional(2D)semiconductors with large domain sizes and high quality is much needed in order to reduce the detrimental efect of grain boundaries on device performance but has proven to be challenging.Here,we analyze the precursor concentration on the substrate surface which signifcantly infuences nucleation density in a vapor deposition growth process and design a confned micro-reactor to grow 2D In_(2)Se_(3) with large domain sizes and high quality.Te uniqueness of this confned micro-reactor is that its size is∼102-103 times smaller than that of a conventional reactor.Such a remarkably small reactor causes a very low precursor concentration on the substrate surface,which reduces nucleation density and leads to the growth of 2D In_(2)Se_(3) grains with sizes larger than 200�m.Our experimental results show large domain sizes of the 2D In_(2)Se_(3) with high crystallinity.Te fexible broadband photodetectors based on the as-grown In_(2)Se_(3) show rise and decay times of 140 ms and 25 ms,efcient response(5.6 A/W),excellent detectivity(7×10^(10) Jones),high external quantum efciency(251%),good fexibility,and high stability.Tis study,in principle,provides an efective strategy for the controllable growth of high quality 2D materials with few grain boundaries. | Lei Tang Changjiu Teng Yuting Luo Usman Khan Haiyang Pan Zhengyang Cai Yue Zhao Bilu Liu Hui-Ming Cheng | 2019 | Research2019，，1： | 7 |
| 13 | Design of PANDA ring-core fiber with 10 polarization-maintaining modes显示文摘We present a polarization-maintaining PANDA ring-core fiber(PM-PRCF) characterized by the combination of a ring-core structure with two stress-applying rods. This special fiber design separates the adjacent modes and avoids the cutoff of the higher-order modes, which is a common problem in elliptical core polarization-maintaining few-mode fibers. Using a high-contrast index ring and stress-induced birefringence, the PM-PRCF features support for 10 vector modes, with effective refractive index separations from their adjacent modes >10^(-4).Broadband performance is investigated subsequently over a wide wavelength range from 1500 to 1630 nm.The proposed fiber is targeted at applications in space-division multiplexing while eliminating the complex multiple-input multiple-output signal processing. | Haozhe Yan Shangyuan Li Zhengyang Xie Xiaoping Zheng Hanyi Zhang Bingkun Zhou | 2017 | Photonics Research2017，5，1： | 7 |
| 14 | Optical observations of LIGO source GW 170817 by the Antarctic Survey Telescopes at Dome A,Antarctica显示文摘The LIGO detection of gravitational waves(GW) from merging black holes in 2015 marked the beginning of a new era in observational astronomy. The detection of an electromagnetic signal from a GW source is the critical next step to explore in detail the physics involved. The Antarctic Survey Telescopes(AST3),located at Dome A, Antarctica, is uniquely situated for rapid response time-domain astronomy with its continuous night-time coverage during the austral winter. We report optical observations of the GW source(GW 170817) in the nearby galaxy NGC 4993 using AST3. The data show a rapidly fading transient at around 1 day after the GW trigger, with the i-band magnitude declining from 17:23 ± 0:13 magnitude to 17:72 ± 0:09 magnitude in ~1:8 h. The brightness and time evolution of the optical transient associated with GW 170817 are broadly consistent with the predictions of models involving merging binary neutron stars. We infer from our data that the merging process ejected about ~10^(-2) solar mass of radioactive material at a speed of up to 30% the speed of light. | lei hu xuefeng wu igor andreoni michael c.b.ashley jeff cooke xiangqun cui fujia du zigao dai bozhong gu yi hu haiping lu xiaoyan li zhengyang li ensi liang liangduan liu bin ma zhaohui shang tianrui sun n.b.suntzeff charling tao syed a.uddin lifan wang xiaofeng wang haikun wen di xiao jin xu ji yang shihai yang xiangyan yuan hongyan zhou hui zhang jilin zhou zonghong zhu | 2017 | Science Bulletin2017，62，21： | 6 |
| 15 | Atmospheric HULIS and its ability to mediate the reactive oxygen species (ROS): A review显示文摘Atmospheric humic-like substances(HULIS) are not only an unresolved mixture of macroorganic compounds but also powerful chelating agents in atmospheric particulate matters(PMs); impacting on both the properties of aerosol particles and health effects by generating reactive oxygen species(ROS). Currently, the interests of HULIS are intensively shifting to the investigations of HULIS-metal synergic effects and kinetics modeling studies, as well as the development of HULIS quantification, findings of possible HULIS sources and generation of ROS from HULIS. In light of HULIS studies, we comprehensively review the current knowledge of isolation and physicochemical characterization of HULIS from atmospheric samples as well as HULIS properties(hygroscopic, surface activity, and colloidal) and possible sources of HULIS.This review mainly highlights the generation of reactive oxygen species(ROS) from PMs, HULIS and transition metals, especially iron. This review also summarized the mechanism of ironorganic complexation and recent findings of OH formation from HULIS-metal complexes. This review will be helpful to carry out the modeling studies that concern with HULIS-transition metals and for further studies in the generation of ROS from HULIS-metal complexes. | Myat Sandar Win Zhengyang Tian Hui Zhao Kai Xiao Jiaxian Peng Yu Shang Minghong Wu Guangli Xiu Senlin Lu Shinich Yonemochi Qingyue Wang | 2018 | Journal of Environmental Sciences2018，30，9： | 6 |
| 16 | Electrochemical machining of burn-resistant Ti40 alloy显示文摘This study investigates the feasibility of using electrochemical machining(ECM) to produce critical aeroengine components from a new burn-resistant titanium alloy(Ti40), thereby reducing costs and improving efficiency relative to conventional mechanical machining.Through this, it is found that an aqueous mix of sodium chloride and potassium bromide provides the optimal electrolyte and that the surface quality of the Ti40 workpiece is improved by using a pulsed current of1 k Hz rather than a direct current.Furthermore, the quality of cavities produced by ECM and the overall material removal rate are determined to be dependent on a combination of operating voltage, electrolyte inlet pressure, cathode feeding rate and electrolyte concentration.By optimizing these parameters, a surface roughness of 0.371 lm has been achieved in conjunction with a specific removal rate of more than 3.1 mm3/A?min. | Xu Zhengyang Liu Jia Zhu Dong Qu Ningsong Wu Xiaolong Chen Xuezhen | 2015 | Chinese Journal of Aeronautics2015，28，4： | 6 |
| 17 | Corrosion behavior of Ti_(3)AlC_(2) in molten KOH at 700℃显示文摘This paper investigated the corrosion behaviors of Ti_(3)AlC_(2) at 700℃in molten KOH with various mass ratios.If the mass ratio of KOH:Ti_(3)AlC_(2)≤2,Ti_(3)AlC_(2) can resist KOH hot corrosion in 2 h.Ti_(3)AlC_(2) suffered serious corrosion attack if the mass ratio≥3.The main compositions of corroded samples were amorphous graphite and potassium titanates(K_(2)O·nTiO_(2)).If the samples were washed by acid and dried,potassium titanates could decompose to K_(2)O and amorphous rutile.Based on the experimental results,a corrosion mechanism of Ti_(3)AlC_(2) in molten KOH was proposed. | Dandan SUN Aiguo ZHOU Zhengyang LI Libo WANG | 2013 | Journal of Advanced Ceramics2013，2，4： | 5 |
| 18 | Adaptive Robust Filtering Algorithm for BDS Medium and Long Baseline Three Carrier Ambiguity Resolution显示文摘For classical TCAR(three carrier ambiguity resolution)algorithm is affected by ionospheric delay and measurement noise,it is difficult to reliably fix ambiguity at medium and long baselines.An improved TCAR algorithm which takes the influence of ionospheric delay into account and has good adaptive robustness is proposed.On the basis of the non-geometric TCAR model,ionospheric delay is obtained by linearly combining extra-wide-lane with fixed ambiguity,and then wide-lane ambiguity is solved.Solving narrow-lane ambiguity by adaptive robust filtering by constructing optimal combination observation,which can effectively improve the fixed success rate of narrow-lane ambiguity and reduce the adverse effects of gross error.Experimental results show that the improved TCAR algorithm can guarantee a high fixed correct rate of wide-lane ambiguity,effectively improve fixed success rate of narrow-lane ambiguity,and has a good ability to resist gross error. | Yangjun GAO Zhiwei LV Pengjin ZHOU Zhengyang JIA Lundong ZHANG Dianwei CONG | 2020 | Journal of Geodesy and Geoinformation Science2020，3，2： | 5 |
| 19 | Cathode design investigation based on iterative correction of predicted profile errors in electrochemical machining of compressor blades显示文摘Electrochemical machining(ECM) is an effective and economical manufacturing method for machining hard-to-cut metal materials that are often used in the aerospace field. Cathode design is very complicated in ECM and is a core problem influencing machining accuracy, especially for complex profiles such as compressor blades in aero engines. A new cathode design method based on iterative correction of predicted profile errors in blade ECM is proposed in this paper. A mathematical model is first built according to the ECM shaping law, and a simulation is then carried out using ANSYS software. A dynamic forming process is obtained and machining gap distributions at different stages are analyzed. Additionally, the simulation deviation between the prediction profile and model is improved by the new method through correcting the initial cathode profile. Furthermore, validation experiments are conducted using cathodes designed before and after the simulation correction. Machining accuracy for the optimal cathode is improved markedly compared with that for the initial cathode. The experimental results illustrate the suitability of the new method and that it can also be applied to other complex engine components such as diffusers. | Zhu Dong Liu Cheng Xu Zhengyang Liu Jia | 2016 | Chinese Journal of Aeronautics2016，29，4： | 5 |
| 20 | Experimental investigation on flow asymmetry in solid entrance region of a square circulating fluidized bed显示文摘To study the influence of back feeding particles on gas-solid flow in the riser, this paper investigated the flow asymmetry in the solid entrance region of a fluidized bed by particle concentration/velocity measurements in a cold square circulating fluidized beds (CFB). The pressure drop distribution along the riser and the saturation carrying capacity of gas for Geldart-B type particles were first analyzed. Under the condition of u0=4 m/s and Gs=21 kg/(m2 s), the back feeding particles were found to penetrate the lean gas-solid flow near the entrance (rear) wall before reaching the opposite (front) wall, thus leading to a relatively denser region near the front wall in the bottom bed. Higher solid circulation rate (u0=4 m/s, Gs=33 kg/(m2 s)) resulted in a higher particle concentration in the riser. However the back feeding particles with higher momentum increased the asymmetry of the particle concentration/velocity profile in the solid entrance region. Lower air velocity (u0=3.2 m/s) and Gs=21 kg/(m2 s), beyond the saturation carrying capacity of gas, induced an S-shaped axial solid distribution with a denser bottom zone. This limited the penetration of the back feeding particles and forced the fluidizing air to flow in the central region, thus leading to a higher solid holdup near the rear wall. Under the conditions of u0=4 m/s and Gs=21 kg/(m2 s), addition of coarse particles (dp=1145 m) into the bed made the radial distribution of solids more symmetrical. | Zhengyang Wang Shaozeng Sun Hao Chen Qigang Deng Guangbo Zhao Shaohua Wu | 2009 | Particuology2009，7，6： | 4 |
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