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| 1 | Enhanced secondary pollution offset reduction of primary emissions during COVID-19 lockdown in China显示文摘To control the spread of the 2019 novel coronavirus(COVID-19),China imposed nationwide restrictions on the movement of its population(lockdown)after the Chinese New Year of 2020,leading to large reductions in economic activities and associated emissions.Despite such large decreases in primary pollution,there were nonetheless several periods of heavy haze pollution in eastern China,raising questions about the well-established relationship between human activities and air quality.Here,using comprehensive measurements and modeling,we show that the haze during the COVID lockdown was driven by enhancements of secondary pollution.In particular,large decreases in NOx emissions from transportation increased ozone and nighttime NO_(3)radical formation,and these increases in atmospheric oxidizing capacity in turn facilitated the formation of secondary particulate matter.Our results,afforded by the tragic natural experiment of the COVID-19 pandemic,indicate that haze mitigation depends upon a coordinated and balanced strategy for controlling multiple pollutants. | Xin Huang Aijun Ding Jian Gao Bo Zheng Derong Zhou Ximeng Qi Rong Tang Jiaping Wang Chuanhua Ren Wei Nie Xuguang Chi Zheng Xu Liangduo Chen Yuanyuan Li Fei Che Nini Pang Haikun Wang Dan Tong Wei Qin Wei Cheng Weijing Liu Qingyan Fu Baoxian Liu Fahe Chai Steven JDavis Qiang Zhang Kebin He | 2021 | National Science Review2021,8,2: | 47 |
| 2 | All-fiber passively mode-locked laser using nonlinear multimode interference of step-index multimode fiber显示文摘We experimentally demonstrate for the first time, to the best of our knowledge, an all-fiber passively mode-locked laser operation based on the nonlinear multimode interference of step-index multimode fiber. Such a structure couples the light in and out of the multimode fiber via single-mode fibers, and its physical mechanisms for saturable absorption have been analyzed theoretically based on the third-order nonlinear Kerr effect of multimode fiber. Using the nonlinear multimode interference structure with 48.8 mm length step-index multimode fiber, the modulation depth has been measured to be ~5%. The passively mode-locked laser output pulses have a central wavelength of 1596.66 nm, bandwidth of 2.18 nm, pulsewidth of ~625 fs, and fundamental repetition rate of8.726 MHz. Furthermore, the influence of total cavity dispersion on the optical spectrum, pulse width, and output power is investigated systematically by adding different lengths of single-mode fiber and dispersion compensation fiber in the laser cavity. | TAO CHEN QIAOLI ZHANG YAPING ZHANG XIN LI HAIKUN ZHANG WEI XIA | 2018 | Photonics Research2018,,11: | 4 |
| 3 | Tunable terahertz wave difference frequency generation in a graphene/AlGaAs surface plasmon waveguide显示文摘Graphene-based surface plasmon waveguides(SPWs) show high confinement well beyond the diffraction limit at terahertz frequencies. By combining a graphene SPW and nonlinear material, we propose a novel graphene/AlGaAs SPW structure for terahertz wave difference frequency generation(DFG) under near-infrared pumps.The composite waveguide, which supports single-mode operation at terahertz frequencies and guides two pumps by a high-index-contrast AlGaAs∕Al Oxstructure, can confine terahertz waves tightly and realize good mode field overlap of three waves. The phase-matching condition is satisfied via artificial birefringence in an AlGaAs∕Al Ox waveguide together with the tunability of graphene, and the phase-matching terahertz wave frequency varies from 4 to 7 THz when the Fermi energy level of graphene changes from 0.848 to 2.456 eV. Based on the coupled-mode theory, we investigate the power-normalized conversion efficiency for the tunable terahertz wave DFG process by using the finite difference method under continuous wave pumps, where the tunable bandwidth can reach 2 THz with considerable conversion efficiency. To exploit the high peak powers of pulses, we also discuss optical pulse evolutions for pulse-pumped terahertz wave DFG processes. | TAO CHEN LIANGLING WANG LIJUAN CHEN JING WANG HAIKUN ZHANG WEI XIA | 2018 | Photonics Research2018,6,3: | 2 |
| 4 | Research on CMOS Mm-Wave Circuits and Systems for Wireless Communications显示文摘This paper discusses some challenges in the design of millimeter-wave(nunwave) circuits and systems for 5th generation(5G) wireless systems in CMOS process.The properties of some passive and active devices such as inductors,capacitors,transmission lines,transformers and transistors in mm-wave frequency band are discussed.Self-healing technique dealing with PVT variation,resonant mode switching technique to enhance frequency tuning range of voltage controlled oscillator(VCO) and dual mode technique for power amplifier(PA) efficiency enhancement are introduced.At last,A fully-integrated60 GHz 5 Gb/s QPSK transceiver with the transmit/receive(T/R) switch in 65 nm CMOS process is introduced.The measured error vector magnitude(EVM) of the TX is-21.9dB while the bit error rate(BER) of the RX with a-52 dBm sine-wave input is below 8e-7when transmitting/receiving 5 Gb/s data.The transceiver is powered by 1.0 V and 1.2 V supply(except the phase-frequency detector and charge-pump in the frequency synthesizer which are powered by 2.5 V supply) and consumes 135 mW in TX mode and 176 mW in RX mode. | JIA Haikun CHI Baoyong KUANG Lixue YU Xiaobao CHEN Lei ZHU Wei WEI Meng SONG Zheng WANG Zhihua | 2015 | China Communications2015,12,5: | 2 |
| 5 | A Preliminary Study on SSR Molecular Markers of White Character of Capsicum显示文摘In this study,Paprika 247 with milk white fruit at marketable maturity stage as male parent and capsicum 246 with green fruit at marketable maturity stage as female parent were selected as experimental materials to screen SSR molecular markers closely related to white fruit character,so as to lay a foundation for the use of SSR technique for molecular marker-assisted breeding and provide reference for breeding of new white capsicum germplasms and varieties. 360 pairs of SSR primers were screened in total,and among them,3 pairs of primers( ES-89,ES-292,ES-296) exhibited remarkable polymorphic differences. This study will provide a basis for next QTL mapping. | Yijia KE Tongguang LIU Haikun JIANG Peng CHEN Xia WANG Fanru ZHOU Yuelei WU Ling FANG Qian ZHANG | 2018 | Agricultural Biotechnology2018,7,3: | 2 |
| 6 | On - road vehi- cle emission inventory and its uncertainty analysis for Shanghai, China显示文摘 | Haikun Wang Changhong Chen Cheng Huang | 2008 | Science of the Total Environment2008,398,: | 1 |
| 7 | On-road vehicle emission inventory and its uncertainty analysis for Shanghai, China显示文摘 | Haikun Wang Changhong Chen Cheng Huang Lixin Fu | 2008 | Science of the Total Environment2008,,1: | 1 |
| 8 | On-road vehicle emission inventory and its uncertainty analysis for Shanghai, China显示文摘 | WANG Haikun CHEN Changhong HUANG Cheng | 2008 | Sei Total Environ2008,398,123: | 1 |
| 9 | High entropy ultra-high temperature ceramic thermal insulator(Zr_(1/5)Hf_(1/5)Nb_(1/5)Ta_(1/5)Ti_(1/5))C with controlled microstructure and outstanding properties显示文摘Due to advancements of hypersonic vehicles,ultra-high temperature thermal insulation materials are urgently requested to shield harsh environment with superhigh heat flux.Toward this target,ultra-high temperature ceramics(UHTCs)are the only choice due to their excellent capability at ultra-high temperatures.We herein report a novel highly porous high entropy(Zr_(1/5)Hf_(1/5)Nb_(1/5)Ta_(1/5)Ti_(1/5))C fabricated by foam-gelcasting-freeze drying technology combined with in-situ pressureless reaction sintering.The porous(Zr_(1/5)Hf_(1/5)Nb_(1/5)Ta_(1/5)Ti_(1/5))C exhibited ultra-high porosity of 86.4%-95.9%,as well as high strength and low thermal conductivity of 0.70–11.77 MPa and 0.164–0.239 W/(m·K),respectively.Specifically,Si C sintering additive only locates at the pit of the surface of sintering neck between UHTC grains,and there is no secondary phase or intergranular film at the grain boundary.Besides,the oxidation resistance of high entropy carbide powders is greatly improved compared with that of the mixed five carbide powders.This work clearly highlights the merits of highly porous high entropy(Zr_(1/5)Hf_(1/5)Nb_(1/5)Ta_(1/5)Ti_(1/5))C as an ultra-high temperature thermal insulation material. | Zhuojie Shao Zhen Wu Luchao Sun Xianpeng Liang Zhaoping Luo Haikun Chen Junning Li Jingyang Wang | 2022 | Journal of Materials Science & Technology2022,,24: | 1 |
| 10 | On-road vehicle emission inventory and its uncertainty analysis for Shanghai, China 显示文摘 | WANG Haikun CHEN Changhong HUANG Cheng | 2008 | Science of the Total Environment2008,398,1: | 1 |
| 11 | Nutrient depletion is the main limiting factor in the crude oil bioaugmentation process显示文摘The biodegradation was considered as the prime mechanism of crude oil degradation.To validate the efficacy and survival of the crude oil-degrading strain in a bioremediation process,the enhanced green fluorescent protein gene(egfp)was introduced into Acinetobacter sp.HC8-3 S.In this study,an oil-contaminated sediment microcosm was conducted to investigate the temporal dynamics of the physicochemical characterization and microbial community in response to bacterium amendment.The introduced strains were able to survive,flourish and degrade crude oil quickly in the early stage of the bioremediation.However,the high abundance cannot be maintained due to the ammonium(NH 4^(+)-N)and phosphorus(PO 4^3--P)contents decreased rapidly after 15 days of remediation.The sediment microbial community changed considerably and reached relatively stable after nutrient depletion.Therefore,the addition of crude oil and degrading cells did not show a long-time impact on the original microbial communities,and sufficient nitrogen and phosphorus nutrients ensures the survive and activity of degrader.Our studies expand the understanding of the crude oil degradative processes,which will help to develop more rational bioremediation strategies. | Yanyu Sun Weiwei Chen Yibo Wang Jie Guo Haikun Zhang Xiaoke Hu | 2021 | Journal of Environmental Sciences2021,33,2: | 1 |
| 12 | A bottom-up methodology to estimate vehicle emissions for the Beijing urban area显示文摘 | Haikun Wang Lixin Fu Xin Lin Yu Zhou Jinchuan Chen | 2008 | Science of the Total Environment2008,,6: | 1 |
| 13 | Porosity, permeability and rock mechanics of Lower Silurian Longmaxi Formation deep shale under temperature-pressure coupling in the Sichuan Basin, SW China显示文摘To investigate the porosity, permeability and rock mechanics of deep shale under temperature-pressure coupling, we selected the core samples of deep shale from the Lower Silurian Longmaxi Formation in the Weirong and Yongchuan areas of the Sichuan Basin for porosity and permeability experiments and a triaxial compression and sound wave integration experiment at the maximum temperature and pressure of 120 ℃ and 70 MPa. The results show that the microscopic porosity and permeability change and the macroscopic rock deformation are mutually constrained, both showing the trend of steep and then gentle variation. At the maximum temperature and pressure, the porosity reduces by 34%–71%, and the permeability decreases by 85%–97%. With the rising temperature and pressure, deep shale undergoes plastic deformation in which organic pores and clay mineral pores are compressed and microfractures are closed, and elastic deformation in which brittle mineral pores and rock skeleton particles are compacted. Compared with previous experiments under high confining pressure and normal temperature,the experiment under high temperature and high pressure coupling reveals the effect of high temperature on stress sensitivity of porosity and permeability. High temperature can increase the plasticity of the rock, intensify the compression of pores due to high confining pressure, and induce thermal stress between the rock skeleton particles, allowing the reopening of shale bedding or the creation of new fractures along weak planes such as bedding, which inhibits the decrease of permeability with the increase of temperature and confining pressure. Compared with the triaxial mechanical experiment at normal temperature, the triaxial compression experiment at high temperature and high pressure demonstrates that the compressive strength and peak strain of deep shale increase significantly due to the coupling of temperature and pressure. The compressive strength is up to 435 MPa and the peak strain exceeds 2%, indicating that high temperature is not conducive to fracture initiation and expansion by increasing rock plasticity. Lithofacies and mineral composition have great impacts on the porosity, permeability and rock mechanics of deep shale. Shales with different lithologies are different in the difficulty and extent of brittle failure. The stress-strain characteristics of rocks under actual geological conditions are key support to the optimization of reservoir stimulation program. | SUN Chuanxiang NIE Haikuan SU Haikun DU Wei LU Ting CHEN Yalin LIU Mi LI Jingchang | 2023 | Petroleum Exploration and Development2023,50,1: | 1 |
| 14 | Construction of apricot variety search engine based on deep learning显示文摘Apricot has a long history of cultivation and has many varieties and types. The traditional variety identification methods are timeconsuming and labor-consuming, posing grand challenges to apricot resource management. Tool development in this regard will help researchers quickly identify variety information. This study photographed apricot fruits outdoors and indoors and constructed a dataset that can precisely classify the fruits using a U-net model (F-score:99%), which helps to obtain the fruit's size, shape, and color features. Meanwhile, a variety search engine was constructed, which can search and identify variety from the database according to the above features. Besides, a mobile and web application (ApricotView) was developed, and the construction mode can be also applied to other varieties of fruit trees.Additionally, we have collected four difficult-to-identify seed datasets and used the VGG16 model for training, with an accuracy of 97%, which provided an important basis for ApricotView. To address the difficulties in data collection bottlenecking apricot phenomics research, we developed the first apricot database platform of its kind (ApricotDIAP, http://gffzz2a5b87b2dfb54266hcc6koxnp0nko6bbw.ffgz.tsg.suse.edu.cn/) to accumulate, manage, and publicize scientific data of apricot. | Chen Chen Lin Wang Huimin Liu Jing Liu Wanyu Xu Mengzhen Huang Ningning Gou Chu Wang Haikun Bai Gengjie Jia Tana Wuyun | 2024 | Horticultural Plant Journal2024,10,2: | 0 |
| 15 | Picosecond dissipative soliton generation from an ytterbium‑doped fber laser based on a BP/SnSe_(2)‑PVA mixture saturable absorber显示文摘Stable picosecond dissipative soliton pulses were observed in an ytterbium-doped fber laser employing a high-quality mixture of BP/SnSe_(2)-PVA saturable absorber(SA).The modulation depth,saturation intensity,and non-saturable loss of the mixture of BP/SnSe_(2)-PVA SA were measured with values of 5.98%,18.37 MW/cm2,and 33%,respectively.Within the pump power range of 150–270 mW,stable dissipative soliton pulses were obtained with an output power of 1.68–4 mW.When the minimum pulse duration is 1.28 ps,a repetition rate of 0.903 MHz,center wavelength of 1064.38 nm and 3 dB bandwidth of 2 nm were obtained.The maximum pulse energy of 4.43 nJ and the signal-to-noise ratio up to 72 dB were achieved at pump power of 270 mW.The results suggest that the BP/SnSe_(2)-PVA mixture SA has outstanding nonlinear saturable absorption characteristics and broad ultrafast laser applications. | Yuting Ouyang Jiayu Zhang Wanggen Sun Mengxiao Li Tao Chen Haikun Zhang Wenjing Tang Wei Xia | 2023 | Frontiers of Optoelectronics2023,16,3: | 0 |
| 16 | Resource abstraction and data placement for distributed hybrid memory pool显示文摘Emerging byte-addressable non-volatile memory(NVM)technologies offer higher density and lower cost than DRAM,at the expense of lower performance and limited write endurance.There have been many studies on hybrid NVM/DRAM memory management in a single physical server.However,it is still an open problem on how to manage hybrid memories efficiently in a distributed environment.This paper proposes Alloy,a memory resource abstraction and data placement strategy for an RDMA-enabled distributed hybrid memory pool(DHMP).Alloy provides simple APIs for applications to utilize DRAM or NVM resource in the DHMP,without being aware of the hardware details of the DHMP.We propose a hotness-aware data placement scheme,which combines hot data migration,data replication and write merging together to improve application performance and reduce the cost of DRAM.We evaluate Alloy with several micro-benchmark workloads and public benchmark workloads.Experimental results show that Alloy can significantly reduce the DRAM usage in the DHMP by up to 95%,while reducing the total memory access time by up to 57%compared with the state-of-the-art approaches. | Tingting CHEN Haikun LIU Xiaofei LIAO Hai JIN | 2021 | Frontiers of Computer Science2021,15,3: | 0 |
| 17 | Microbial synthesis of N, P co-doped carbon supported PtCu catalysts for oxygen reduction reaction显示文摘Developing highly efficient and stable platinum-based electrocatalyst for oxygen reduction reaction(ORR) is critical to expediting commercialization of fuel cells.Herein,several PtCu alloy nanocatalysts supported on N,P co-doped carbon(PtCu/NPC) were prepared by microbial-sorption and carbonization-reduction.Among them,PtCu/NPC-700 ℃ exhibits excellent catalytic performance for ORR with a mass activity of 0.895 A mg_(pt)^(-1)(@0.9 V) which is 8.29 folds of commercial Pt/C.Additionally,the ECSA and MA of PtCu/NPC-700℃ only decrease by 14.2% and 18.7% respectively,while Pt/C decreases by 35.2% and 52.8% after 10,000 cycles of ADT test.Moreover,the PtCu/NPC-700℃ catalyst emanates a maximum power density of 715 mW cm^(-2) and only 11.1% loss of maximum power density after 10,000 ADTs in single-cell test,indicating PtCu/NPC-700℃ also manifests higher activity and durability in actual single-cell operation than Pt/C.This research provides an easy and novel strategy for developing highly active and durable Pt-based alloy catalyst. | Shaohui Zhang Suying Liu Jingwen Huang Haikun Zhou Xuanzhi Liu Pengfei Tan Haoyun Chen Yili Liang Jun Pan | 2023 | Journal of Energy Chemistry2023,,9: | 0 |
| 18 | On Estimating Magnitude of a Maximum Sequent Earthquake by Viscoelastic Coulomb Stress Change and a Discussion of the Relationship between the M_S7.3 Earthquakes in Yutian 2008 and 2014显示文摘On the basis of the previous studies of the layered crustal model in the Yutian area,combined with the field GPS continuous observation data,we roughly estimate the viscous coefficient of each layer. With the viscoelastic horizontal layer model,we calculate the viscoelastic co-seismic Coulomb stress change caused by the Yutian M_S7. 3 earthquakes 2008 and 2014 respectively. Based on the Coulomb stress change,using the calculation method of 'direct 'aftershock frequency,we come up with the theoretical earthquake frequency directly related to the mainshock and the co-seismic Coulomb stress change in the study area. Then we put forward a method,based on the comparison of theoretical and actual earthquake frequency or the comparison between theoretical and practical earthquake frequency-distance decay curve fitting residuals,to estimate the magnitude of a maximum sequent earthquake,directly related to the mainshock co-seismic Coulomb stress change. Results calculated by different methods show that the maximum follow-up earthquake magnitude caused by the coseismic Coulomb stress change lies from M_S7. 2 to M_S7. 5 following Yutian M_S7. 3 earthquake in 2008; but that of the 2014 Yutian M_S7. 3 earthquake is M_S6. 3. The former is very close to the Yutian M_S7. 3 earthquake in 2014.Because of the same magnitude,relatively close spatial distance,short time interval,the same region of the external force,the strong correlation between two seismic tectonic and a clear stress interaction,we thus consider that the two Yutian M_S7. 3 earthquakes in 2008 and 2014 constitute a pair of generalized double shock type earthquake. This is consistent with the sequence type characteristic of past 'double shock'earthquakes in the region. In this paper,the influence of the magnitude lower limit and the b-value in the relationship of G-R on the results is discussed. As a result,when the viscoelastic coseismic Coulomb stress variation is determined,the lower limit of magnitude has little effect on the maximum sequent earthquake magnitude estimation,but b-value of G-R has a greater impact on the results. | Chen Yanan Jiang Haikun | 2015 | Earthquake Research in China2015,29,4: | 0 |
| 19 | Effective regulation of electronic structures and luminescence properties of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)phosphors by tetrahedral substitution显示文摘A series of Dy^(3+)-activated phosphors with the general formula LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)(0≤x≤3)characterized by an apatite-type structure were successfully synthesized via a simple solid-state technique involving a partial substitution of[SiO_(4)]^(4-)with[GeO_(4)]^(4-)species.The effects of homovalent[GeO_(4)]^(4-)-[SiO_(4)]^(4-)substitution on the crystal structure,electronic structure,luminescence properties and thermal performance of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)phosphors were studied in details.The phases and microstructure were performed by using X-ray diffraction(XRD)Rietveld refinement method and scanning electron microscopy(SEM)characterization.The substitution of smaller[SiO_(4)]^(4-)ions by larger[GeO_(4)]^(4-)ones makes their unit cell parameters increase gradually,and their band gaps decrease.The photoluminescence spectra of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)(0≤x≤3)exhibit obvious emission peaks located at 477,573 and 675 nm within a visible wavelength region,resulting in an excellent white light.Furthermore,the I573nm/I477nm values of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):Dy^(3+)(0≤x≤3)become larger with the partial substitution of[SiO_(4)]^(4-)by[GeO_(4)]^(4-),and their CIE chromaticity coordinates exhibit a yellow shift. | Yuanyuan Zhang Lefu Mei Haikun Liu Sergey M.Aksenov Dina V.Deyneko Deliang Chen | 2023 | Journal of Rare Earths2023,41,5: | 0 |
| 20 | Oxidation behavior of non-stoichiometric(Zr,Hf,Ti)C_(x) carbide solid solution powders in air显示文摘Multi-component solid solutions with non-stoichiometric compositions are characteristics of ultra-high temperature carbides as promising materials for hypersonic vehicles.However,for group IV transition-metal carbides,the oxidation behavior of multi-component non-stoichiometric(Zr,Hf,Ti)C_(x)carbide solid solution has not been clarified yet.The present work fabricated four kinds of(Zr,Hf,Ti)C_(x)carbide solid solution powders by free-pressureless spark plasma sintering to investigate the oxidation behavior of(Zr,Hf,Ti)C_(x)in air.The effects of metallic atom composition on oxidation resistance were examined.The results indicate that the oxidation kinetics of(Zr,Hf,Ti)C_(x)are composition dependent.A high Hf content in(Zr,Hf,Ti)C_(x)was beneficial to form an amorphous Zr-Hf-Ti-C-0 oxycarbide layer as an oxygen barrier to enhance the initial oxidation resistance.Meanwhile,an equiatomic ratio of metallic atoms reduced the growth rate of(Zr,Hf,Ti)O_(2)oxide,increasing its phase stability at high temperatures,which improved the oxidation activation energy of(Zr,Hf,Ti)C_(x). | Huilin LUN Yi ZENG Xiang XIONG Ziming YE Zhongwei ZHANG Xingchao LI Haikun CHEN Yufeng LIU | 2021 | Journal of Advanced Ceramics2021,10,4: | 0 |