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| 1 | Trends in particulate matter and its chemical compositions in China from 2013–2017显示文摘Accurate determination of the atmospheric particulate matter mass concentration and chemical composition is helpful in exploring the causes and sources of atmospheric enthalpy pollution and in evaluating the rationality of environmental air quality control strategies.Based on the sampling and chemical composition data of PM2.5 in different key regions of China in the CARE-China observation network,this research analyzes the environmental air quality data released by the China National Environmental Monitoring Centre during the studied period to determine the changes in the particulate matter mass concentration in key regions and the evolution of the corresponding chemical compositions during the implementation of the Action Plan for Prevention and Control of Air Pollution from 2013-2017.The results show the following.(1)The particulate matter mass concentration in China showed a significant downward trend;however,the PM2.5 annual mass concentration in 64%of cities exceeds the New Chinese Ambient Air Quality Standard(CAAQS)GradeⅡ(GB3095-2012).The region to the east of the Taihang Mountains,the Fenhe and Weihe River Plain and the Urumqi-Changji regions in Xinjiang,all have PM2.5 concentration loading that is still high,and heavy haze pollution occurred frequently in the autumn and winter.(2)During the heavy pollution in the autumn and winter,the concentrations of sulfate and organic components decreased significantly.The mean SO42-concentration in PM2.5 decreased by 76%,12%,81%and 38%in Beijing-Tianjin-Hebei(BTH),the Pearl River Delta(PRD),the Sichuan-Chongqing region(SC)and the Fenhe and Weihe River Plain,respectively.The mean organic matter(OM)concentration decreased by 70%,44%,48%and 31%,respectively,and the mean concentration of NH4+decreased by 68%,1.6%,38%and 25%,respectively.The mean elemental carbon(EC)concentration decreased by 84%and 20%in BTH and SC,respectively,and it increased by 61%and 11%in the PRD and Fenhe and Weihe River Plain,respectively.The mean concentration of mineral and unresolved chemical components(MI)dropped by 70%,24%and 13%in BTH,the PRD and the Fenhe and Weihe River Plain,respectively.The change in the PM2.5 chemical composition is consistent with the decrease of the PM2.5mass concentration.(3)In 2015,the mean OM concentration contributions to fine particles and coarse particles were 13-46%and 46-57%,respectively,and the mean MI concentration contributions to fine particles and coarse and particles were 31-60%and 39-73%,respectively;these values are lower than the 2013 values from the key regions,which is the most important factor behind the decrease of the particulate matter mass concentration.From 2013 to 2015,among the chemical components of different particle size fractions,the peak value of the coarse particle size fraction decreased significantly,and the fine particle size fractions of SO42-,NO3-,and NH4+decreased with the decrease of the particulate matter mass concentration in different particle size fractions.The fine-particle size peaks of SO42-,NO3-and NH4+shifted from 0.65-1.1μm to the finer size range of0.43-0.65μm during the same time frame. | Yuesi WANG Wenjie LI Wenkang GAO Zirui LIU Shili TIAN Rongrong SHEN Dongsheng JI Shuai WANG Lili WANG Guiqian TANG Tao SONG Mengtian CHENG Gehui WANG Zhengyu GONG Jiming HAO Yuanhang ZHANG | 2019 | Science China Earth Sciences2019，62，12： | 23 |
| 2 | A novel method for singularity analysis of the 6-SPS parallel mechanisms显示文摘Singularity analysis is a basic problem of parallel mechanism, and this problem cannot be avoided in both workspace and motion planning. How to express the singularity locus in an analytical form is the research emphasis for many researchers for a long time. This paper presents a new method for the singularity analysis of the 6-SPS parallel mechanism. The rotation matrix is described by quaternion, and both the rotation matrix and the coordinate vectors have been expanded to four-dimensional forms. Through analyzing the coupling relationship between the position variables and the orientation variables, utilizing properties of the quaternion, eight equivalent equations can be obtained. A new kind of Jacobian matrix is derived from those equations, and the analytical expression of the singularity locus is obtained by calculating the determinant of the new Jacobian matrix. The singularity analysis of parallel mechanisms, whose moving platform actuated by 6 links and the vertices of both the base and the moving platforms has been placed on a circle respectively, can be solved by this analytical expression. | CHENG ShiLi WU HongTao WANG ChaoQun YAO Yu ZHU JianYing | 2011 | Science China(Technological Sciences)2011，54，5： | 15 |
| 3 | T cell immune responses to SARS-CoV-2 and variants of concern(Alpha and Delta)in infected and vaccinated individuals显示文摘Our understanding of immune responses to SARS-CoV-2 and variants of concern(VOCs)has been primarily acquired through analysis of Spike-specific IgG responses.However,a more comprehensive understanding of the breadth and longevity of immune responses after infection and vaccination requires analysis of cellular immunity.Herein,we report on T cell immunity in infected and vaccinated individuals,identifying CD4+/CD8+T cell cytokine responses to SARS-CoV-2 and variant peptides(Alpha,B.1.1.7 and Delta,B.1.617.2). | Stanley C.Jordan Bong-Ha Shin Terry-Ann M.Gadsden Maggie Chu Anna Petrosyan Catherine N.Le Rachel Zabner Jillian Oft Isabel Pedraza Susan Cheng Ashley Vo Noriko Ammerman Jasmine Plummer Shili Ge Max Froch Anders Berg Mieko Toyoda Ruan Zhang | 2021 | Cellular & Molecular Immunology2021，18，11： | 3 |
| 4 | Local electrical charac terization of t wo-dimensional mat erials with functional atomic force microscopy显示文摘Research about two-dimensional (2D) materials is growing exponentially across various scientific and engineering disciplines due to the wealth of unusual physical phenomena that occur when charge transport is confined to a plane. The applications of 2D materials are highly affected by the electrical properties of these mat erials, including curren t dist ribution, surface pot ential, dielectric response, conductivity, perm计tivity, and piezoelectric response. Hence, it is very crucial to characterize these properties at the nanoscale. The Atomic Force Microscopy (AFM)-based techniques are powerful tools that can simultaneously characterize morphology and electrical properties of 2D materials with high spatial resolution, thus being more and more extensively used in this research field. Here, the principles of these AFM techniques are reviewed in detail. After that, their representative applications are further demonstrated in the local characterization of various 2D materials? elcctrical properties. | Sabir Hussain Kunqi Xu Shili Ye Le Lei Xinmeng Liu Rui Xu Liming Xie Zhihai Cheng | 2019 | Frontiers of physics2019，14，3： | 2 |
| 5 | From borophosphate to fluoroborophosphate:a rational design of fluorine-induced birefringence enhancement显示文摘The introduction of oxofluoride anion into anionic group assists to tune optical properties owing to the change of coordination,electronegativity,and according anionic framework.Here,we proposed a rational design of new compounds by fluorine-driven structure and optical property evolution.A new borophosphate Ba_(2)BP_(3)O_(11)with the monoclinic space group P2_(1/c) has been synthesized in the sealed system.Ba_(2)BP_(3)O_(11)exhibits a rare P-O-P bridge formation,which is the first example in alkaline-earth metal borophosphates.By further substituting[BO_(4)]^(3-)with[BO_(3)F]^(4-),the first alkaline-earth metal/lead fluoroborophosphates M_(2)BP_(2)O_(8)F(M=Ba and Pb)with the same space group were designed.Since the scissors effect of fluorine,in M_(2)BP_(2)O_(8)F(M=Ba and Pb),a BO_(3)F tetrahedron corner-sharing with three PO_(4)tetrahedra forms 1D chains along the b-axial direction,which are filled by MO_(n)(M=Ba/Pb,n=5,6,8)distorted polyhedra.The first principles calculation shows that the borophosphate Ba_(2)BP_(3)O_(11)has a birefringence about 0.013@1,064 nm,while the fluoroborophosphates M_(2)BP_(2)O_(8)F(M=Ba and Pb)have the values of 0.035 and 0.043@1,064 nm,respectively.Such an apparent enhancement in birefringence is derived from synergies of the oxyfluoride and cation.The introduction of fluorine-containing heteroanionic groups provides a feasible strategy to design novel promising optical materials. | Wenyao Zhang Zhizhong Zhang Wenqi Jin Ruonan Zhang Meng Cheng Zhihua Yang Shilie Pan | 2021 | Science China Chemistry2021，64，9： | 1 |
| 6 | High harmonic exploring on different materials in dynamic atomic force microscopy显示文摘In atomic force microscopy(AFM), high-frequency components consisted in dynamic tip-sample interaction have been recently demonstrated as a promising technique for exploring more extensive material properties. Here we present an exploratory study of high harmonic atomic force microscopy by force-spectroscopy and high harmonic imaging. Since these components are very weak compared to the fundamental response, we firstly designed a high harmonic cantilever by tuning the second order flexural resonance frequency to an integer 6 times of its fundamental mode(i.e. ω_2=6ω_1). Moreover, it is verified that high harmonic can discern extra features than topographies on different samples with amplitude/frequency modulation(AM/FM) dynamic AFM mode. In AM mode, the first resonance amplitude and 6 th harmonic amplitude were discussed. The 6 th harmonic is more sensitive than the first order response. In FM mode, it is noted that the decaying rate of the 6 th harmonic frequency is approximately 6 multiples to the slope of the fundamental frequency shift when the tip approaches to the surface of sample. This non-destructive method was also adopted to investigate the local interlayer coupling and intercalation in the two-dimensional graphene films tentatively. | ZHENG ZhiYue XU Rui YE ShiLi HUSSAIN Sabir JI Wei CHENG Peng LI YanJun SUGAWARA Yasuhiro CHENG ZhiHai | 2018 | Science China(Technological Sciences)2018，61，3： | 1 |
| 7 | TheForward Kinematics Analysis of 6-3 Stewart Par-allel Mechanisms显示文摘 | Cheng Shili Wu Hongtao Wang Chaoqun | 2010 | Intelligent Robotics and Ap-plications2010，6424，： | 1 |
| 8 | Heating-induced aggregation control for efficient sequential-cast organic solar cells显示文摘The aggregation and morphology within the photoactive layer is of considerable significance to boost the power-conversion efficiency(PCE)of organic solar cells(OSCs).Herein,heating-induced aggregation control of nonfullerene acceptor BTPeC7 during sequential casting was demonstrated.The large aggregates of BTP-eC7 can be significantly reduced by sequential casting of BTP-eC7 hot solution on the D18 fibrillar layer,and further eliminated by sequential casting of BTP-eC7 hot solution on the D18 fibrillar layer heated on hot substrate,leading to stronger faceonπ–πstacking and appropriate phase separation within the photoactive layer to promote exciton dissociation and charge transfer.The maximum PCE of D18/BTPeC7 solar cells can be enhanced from 8.1%of room temperature casting to 15.9%of hot solution,hot-substrate casting,therefore demonstrates that heating-induced aggregation and sequential-casting strategies are a promising approach in improving the performance of OSCs employing nonfullerene acceptors with limited solubility or strong crystallization ability. | Donghui Li Chuanhang Guo Xue Zhang Baocai Du Pang Wang Shili Cheng Jinlong Cai Hui Wang Dan Liu Huifeng Yao Jianhui Hou Tao Wang | 2022 | Aggregate2022，3，3： | 0 |
| 9 | A Cation-Driven Approach toward Deep-Ultraviolet Nonlinear Optical Materials显示文摘The design of new materials with special performances is still a great challenge,especially for the deep-ultraviolet nonlinear optical materials in which it is difficult to balance large bandgaps and strong second harmonic generation responses due to their inverse relationship.Cation variation not only influences the whole structure frameworks but also directly participates in the formation of electronic structures,both of which could lead to the uncontrollability of the properties of the designed materials.Here,a novel approach,aiming at purposeful and foreseeable material designs,is proposed to characterize the role of cations.By the verification of several series of borates,the influences of cation variation on property changes are explored systematically.Accordingly,a feasible strategy of designing deep-ultraviolet nonlinear optical materials by substituting barium for lead has been concluded,which could obviously blue-shift the ultraviolet cutoff edge and maintain the relatively strong second harmonic generation response(more than 2 times of KH2PO4),achieving the property optimization,and especially works efficiently in fluorooxoborates.The property optimization design strategy and the cation characterization method are not only helpful in exploring nonlinear optical materials but also enlightening in material design and selection. | Cong Hu Meng Cheng Wenqi Jin Jian Han Zhihua Yang Shilie Pan | 2023 | Research2023，，3： | 0 |
| 10 | (NH_(4))_(3)B_(11)PO_(19)F_(3):a deep-UV nonlinear optical crystal with unique[B_(5)PO_(10)F]_(∞)layers显示文摘Deep-ultraviolet(DUV)nonlinear optical(NLO)crystals that can extend the output range of coherent light below 200 nm are pivotal materials for solid-state lasers.To date,KBe_(2)BO_(3)F_(2)(KBBF)is the only usable crystal that can generate DUV coherent light by direct second harmonic generation(SHG),but the layered growth habit and toxic ingredients limit its application.Herein,we report a new fluoroborophosphate,(NH_(4))_(3)B_(11)PO_(19)F_(3)(ABPF),containing four different functional units:[BO_(3)],[BO_(4)],[BO_(3)F]and[PO_(4)].ABPF exhibits a KBBF-like structure while eliminating the limitations of KBBF crystal.The unique[B_(5)PO_(10)F]_(∞)layers enhance ABPF’s performance;for example,it has a large SHG response(1.2×KDP)and a sufficient birefringence(0.088 at 1064 nm)that enables the shortest phase-matching wavelength to reach the DUV region.Meanwhile,the introduction of strong B-O-P covalent bonds decreases the layered growth habit.These findings will enrich the structural chemistry of fluoroborophosphate and contribute to the discovery of more excellent DUV NLO crystals. | Bingliang Cheng Zijian Li Yu Chu Abudukadi Tudi Miriding Mutailipu Fangfang Zhang Zhihua Yang Shilie Pan | 2022 | National Science Review2022，9，8： | 0 |
| 11 | Non-fullerene acceptor pre-aggregates enable high efficiency pseudo-bulk heterojunction organic solar cells显示文摘Pseudo-bulk heterojunction(BHJ)fabricated by sequential casting of donor and acceptor layers has been recently demonstrated as a superior structure to prepare organic solar cells(OSCs)with enhanced efficiency compared to the conventional BHJ OSCs cast from a common solution of donors and acceptors.However,molecular diffusion and aggregation within the pseudo-BHJ layer bring great challenges to fully realize the advantage of pseudo-BHJ structure.Herein,a solution-incubated pre-aggregation strategy is employed to tune the nanoscale aggregates of non-fullerene acceptor(NFA)BTP-e C11 and N3 to substantially enhance device power-conversion efficiency(PCE).NFA pre-aggregates are incubated in solutions via aging or adding antisolvent,and then sequentially cast onto D18 fibrillar network,which then penetrate to form a pseudo-BHJ structure with appropriate domain sizes to ensure superior charge mobilities.While the conventional pseudo-BHJ OSCs obtain inferior PCEs below 17%compared with normal BHJ OSCs,NFA pre-aggregates help to achieve remarkable PCEs of 17.7%and 17.5%for D18/BTP-e C11 and D18/N3 pseudo-BHJ OSCs.This work demonstrates that the solution-incubated nanoscale pre-aggregation is an efficient approach to regulate molecular diffusion and aggregation to guarantee high performance pseudo-BHJ OSCs. | Donghui Li Chuanhang Guo Xue Zhang Baocai Du Cong Yu Pang Wang Shili Cheng Liang Wang Jinlong Cai Hui Wang Dan Liu Huifeng Yao Yanming Sun Jianhui Hou Tao Wang | 2022 | Science China Chemistry2022，65，2： | 0 |
| 12 | Amplification effect of near-field ground motion around deep tunnels based on finite fracturing seismic source model显示文摘Dynamic failure of rock masses around deep tunnels,such as fault-slip rockburst and seismic-induced collapse,can pose a significant threat to tunnel construction safety.One of the most significant factors that control the accuracy of its risk assessment is the estimation of the ground motion around a tunnel caused by seismicity events.In general,the characteristic parameters of ground motion are estimated in terms of empirical scaling laws.However,these scaling laws make it difficult to accurately estimate the near-field ground motion parameters because the roles of control factors,such as tunnel geometry,damage zone distribution,and seismic source parameters,are not considered.For this,the finite fracturing seismic source model(FFSSM)proposed in this study is used to simulate the near-field ground motion characteristics around deep tunnels.Then,the amplification effects of ground motion caused by the interaction between seismic waves and deep tunnels and corresponding control factors are studied.The control effects of four factors on the near-field ground motion amplification effect are analyzed,including the main seismic source wavelength,tunnel span,tunnel shape,and range of damage zones.An empirical formula for the maximum amplification factor(a_(m))of the near-field ground motion around deep tunnels is proposed,which consists of four control factors,i.e.the wavelength control factor(F_(λ)),tunnel span factor(F_(D)),tunnel shape factor(F_(s))and excavation damage factor(F_(d)).This empirical formula provides an easy approach for accurately estimating the ground motion parameters in seismicityprone regimes and the rock support design of deep tunnels under dynamic loads. | Qiankuan Wang Shili Qiu Yao Cheng Shaojun Li Ping Li Yong Huang Shirui Zhang | 2022 | Journal of Rock Mechanics and Geotechnical Engineering2022，14，6： | 0 |
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