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Incorporation of source contributions to improve the accuracy of soil heavy metal mapping using small sample sizes at a county scale

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Pedosphere 2024年第1期34卷 170-180页

作者： Jie SONG xin WANG Dongsheng YU Jiangang LI Yanhe ZHAO Siwei WANG Lixia ma State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Chinese Academy of Sciences University Beijing 100049China Agricultural and Rural Bureau of Luanping County Luanping 068250China

Estimating heavy metal(HM) distribution with high precision is the key to effectively preventing Chinese medicinal plants from being polluted by the native soil. A total of 44 surface soil samples were gathered to detect the concentrations of eight HMs(As, Hg, Cu, Cr, Ni, Zn, Pb, and Cd) in the herb growing area of Luanping County, northeastern Hebei Province, China. An absolute principal component score-multiple linear regression(APCS-MLR) model was used to quantify pollution source contributions to soil HMs. Furthermore, the source contribution rates and environmental data of each sampling point were simultaneously incorporated into a stepwise linear regression model to identify the crucial indicators for predicting soil HM spatial distributions. Results showed that 88% of Cu, 72% of Cr, and 72% of Ni came from natural sources;50% of Zn, 49% of Pb, and 59% of Cd were mainly caused by agricultural activities;and 44% of As and 56% of Hg originated from industrial activities. When three-type(natural, agricultural, and industrial) source contribution rates and environmental data were simultaneously incorporated into the stepwise linear regression model, the fitting accuracy was significantly improved and the model could explain 31%–86% of the total variance in soil HM concentrations. This study introduced three-type source contributions of each sampling point based on APCS-MLR analysis as new covariates to improve soil HM estimation precision, thus providing a new approach for predicting the spatial distribution of HMs using small sample sizes at the county scale.

关键词： absolute principal component score-multiple linear regression Chinese herbal medicine influencing factors spatial distribution stepwise multiple regression

Multiscale microstructural consideration of enhanced shear strength in TiAl intermetallic/K4169 alloy composite joints prepared by vacuum brazing with(Ti,Zr)-Ni-based amorphous filler metal

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Journal of materials Science & Technology 2024年第5期172卷 51-70页

作者： Liangliang Zhang Honggang Dong peng Li Baosheng Wu Yueting ma Libing Huang Chao Li Jiachen Li School of materials Science and Engineering Dalian University of TechnologyDalian 116024China

TiAl intermetallic could be used to replace Ni-based alloy in assemblies to generate excellent specific strength.A(Ti,Zr)-Ni-based amorphous filler metal Ti_(21.25)Zr_(25)Ni_(25)Cu_(18.75)(at.%)was designed using a cluster-plus-glue-atom model to successfully vacuum braze K4169 and TiAl bimetallic *** various brazing temperatures and holding time,the quantitative relationships between lattice distortion,grain boundary,dislocation density,and hardness,elastic modulus,shear strength of the joints were ***,the fracture mechanism of the joints was *** brazed seam mainly consisted of solid diffusion reaction layers(ZonesⅠandⅢ)and filler metal residue zone(ZoneⅡ).When the brazing temperature increased to 1030℃,grain refinement occurred in the brazed ***Ⅰwas primarily composed of(Ni)ss[0-11]+TiNi[011]/(Cr,Fe,Ni)ss[0-11]/(Ti,Zr)Ni[0-1-1]+(Cr,Fe,Ni)ss[0-11].The(Ti,Zr)(Ni,Cu)[001]and(Ti,Zr)(Ni,Cu)[101]intermetallic compound-based solid solutions were formed in ZoneⅡ.And the lattice distortion of(Ti,Zr)(Ni,Cu)[101]and(Ti,Zr)(Ni,Cu)[001]was 32.05%and 14.82%,*** a result,the proportion of low angle grain boundaries(LAGBs)and deformed grains in ZoneⅡrose to 38.6%and 38.7%.In ZonesⅠandⅢ,the proportion of LAGBs reduced to 8%and 3.4%,*** the holding time increased,the long-range diffusion of Al in ZoneⅡcaused the(Ti,Zr)(Ni,Cu)[001]with cubic structure to transform into(Ti,Zr)(Ni,Cu,Al)[00-1]with hexagonal crystal system structure,where the lattice distortion was 4.42%and 10.49%for a and *** 1030℃/10 min,the average geometrically nec-essary dislocation densities(GNDs)in ZonesⅠ,ⅡandⅢwere 9.87×10^(14)m^(-2),8.55×10^(14)m^(-2)and 11.4×10^(14)m^(-2),***,the shear strength of joints reached 322 MPa due to the lattice distortion,dislocation strengthening and fine grain ***,the plastic and brittle hard phases were generated in ZoneⅡand displayed a mechanical interlocking structure tha

关键词： K4169/Ti_(21.25)Zr_(25)Ni_(25)Cu_(18.75)/TiAl composite joints Intermetallic compound-based solid solution Lattice distortion Elastic modulus

A layered multifunctional framework based on polyacrylonitrile and MOF derivatives for stable lithium metal anode

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Journal of Energy Chemistry 2024年第6期93卷 282-288,I0007页

作者： Fanfan Liu peng Zuo Jing Li pengcheng Shi Yu Shao Linwei Chen Yihong Tan Tao ma Engineering Research Center of High-frequency Soft magnetic materials and Ceramic Powder materials of Anhui Province School of Chemistry and Material EngineeringChaohu UniversityHefei 238024AnhuiChina Frontiers Science Center for Transformative Molecules School of Chemistry and Chemical EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Pharmacy Anhui University of Chinese MedicineHefei 230012AnhuiChina School of materials and Energy Guangdong University of TechnologyGuangzhou 510006GuangdongChina Jiujiang DeFu Technology Co. Ltd.Jiujiang 332000JiangxiChina

Composite Li metal anodes based on three-dimensional(3D) porous frameworks have been considered as an effective material for achieving stable Li metal batteries with high energy ***,uneven Li deposition behavior still occurs at the top of 3D frameworks owing to the local accumulation of Li *** promote uniform Li deposition without top dendrite growth,herein,a layered multifunctional framework based on oxidation-treated polyacrylonitrile(OPAN) and metal-organic framework(MOF) derivatives was proposed for rationally regulating the distribution of Li ions flux,nucleation sites,and electrical *** from these merits,the OPAN/carbon nano fiber-MOF(CMOF) composite framework demonstrated a reversible Li plating/stripping behavior for 500 cycles with a stable Coulombic efficiency of around 99.0% at the current density of 2 ma/cm~***,such a Li composite anode exhibited a superior cycle lifespan of over 1300 h under a low polarized voltage of 18 mV in symmetrical *** the Li composite anode was paired with LiFePO_(4)(LFP) cathode,the obtained full cell exhibited a stable cycling over 500 ***,the COMSOL Multiphysics simulation was conducted to reveal the effects on homogeneous Li ions distribution derived from the above-mentioned OPAN/CMOF framework and electrical insulation/conduction *** electrochemical and simulated results shed light on the difficulties of designing stable and safe Li metal anode via optimizing the 3D frameworks.

关键词： Lithium metal anode Layered multifunctional framework Ions flux redistribution Electrical insulation/conduction structure Uniform Li deposition

Effective regulation of the interaction process among three optical solitons

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Chinese Physics B 2024年第10期33卷 190-197页

作者： Houhui Yi Xiaofeng Li Junling Zhang xin Zhang Guoli ma School of Intelligent manufacturing Weifang University of Science and TechnologyWeifang 262700China School of Aviation and Aerospace Tianjin Sino-German University of Applied SciencesTianjin 300350China

The interaction between three optical solitons is a complex and valuable research direction,which is of practical application for promoting the development of optical communication and all-optical information processing *** this paper,we start from the study of the variable-coefficient coupled higher-order nonlinear Schodinger equation(VCHNLSE),and obtain an analytical three-soliton solution of this *** on the obtained solution,the interaction of the three optical solitons is explored when they are incident from different initial velocities and *** the higher-order dispersion and nonlinear functions are sinusoidal,hyperbolic secant,and hyperbolic tangent functions,the transmission properties of three optical solitons before and after interactions are ***,this paper achieves effective regulation of amplitude and velocity of optical solitons as well as of the local state of interaction process,and interaction-free transmission of the three optical solitons is obtained with a small *** relevant conclusions of the paper are of great significance in promoting the development of high-speed and large-capacity optical communication,optical signal processing,and optical computing.

关键词： optical solitons solitons interactions nonlinear Schr¨odinger equation higher-order dispersion and nonlinear effects

The size effect and analogous boundary states in a circular non-Hermitian chain

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Communications in Theoretical Physics 2024年第2期76卷 157-165页

作者： xin-Yu ma Yi-Han Guan Qiao-Nan Li Ai-Lei He Lu Qi School of Physical Science and Technology Yangzhou UniversityYangzhou 225002China

We investigate the size effect and boundary states based on a circular non-Hermitian chain under the nonreciprocal intra-cell coupling and inter-cell coupling *** find that the circular non-Hermitian chain exhibits an even–odd effect on the unit cell corresponding to a large chain,which is different from the open non-Hermitian chain only exhibiting the same effect for a small ***,we find that the originally localized bulk states become totally extended via designing the boundary coupling strength *** extended bulk states reveal the fact of the disappearance of the non-Hermitian skin *** particular,we show that the circular non-Hermitian chain also possesses the analogous edge states under some parameter regimes,which is pretty counterintuitive since the circular chain usually cannot define a *** investigations supply the different non-Hermitian phenomena in a circular non-Hermitian chain.

关键词： boundary states non-Hermitian chain topological state

Intelligent gold nanocluster for effective treatment of malignant tumor via tumor-specific photothermal–chemodynamic therapy with AIE guidance

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National Science Review 2024年第5期11卷 326-342页

作者： Feng Liu Tianfeng Yang Xiaowei Chang Li Chen Cheng Cheng Xiuhong peng Haihu Liu Yanmin Zhang xin Chen School of Energy and Power Engineering Xi'an Jiaotong University Department of Chemical Engineering Shaanxi Key Laboratory of Energy Chemical Process IntensificationInstitute of Polymer Science in Chemical Engineering School of Chemical Engineering and Technology Xi'an Jiaotong University School of Pharmacy Health Science Center Xi'an Jiaotong University

Precise and efficient therapy of malignant tumors is always a challenge. Herein, gold nanoclusters co-modified by aggregation-induced-emission（AIE） molecules, copper ion chelator（acylthiourea） and tumor-targeting agent（folic acid） were fabricated to perform AIE-guided and tumor-specific synergistic therapy with great spatio-temporal controllability for the targeted elimination and metastasis inhibition of malignant tumors. During therapy, the functional gold nanoclusters（Au NTF） would rapidly accumulate in the tumor tissue due to the enhanced permeability and retention effect as well as folic acid-mediated tumor targeting, which was followed by endocytosis by tumor cells. After that, the overexpressed copper ions in the tumor cells would trigger the aggregation of these intracellular Au NTF via a chelation process that not only generated the photothermal agent in situ to perform the tumor-specific photothermal therapy damaging the primary tumor, but also led to the copper deficiency of tumor cells to inhibit its ***, the copper ions were reduced to cuprous ions along with the chelation, which further catalysed the excess H2O2in the tumor cells to produce cytotoxic reactive oxygen species, resulting in additional chemodynamic therapy for enhanced antitumor efficiency. The aggregation of Au NTF also activated the AIE molecules to present fluorescence, which not only imaged the therapeutic area for real-time monitoring of this tumor-specific synergistic therapy, but also allowed us to perform near-infrared radiation at the correct time point and location to achieve optimal photothermal therapy. Both in vitro and in vivo results revealed the strong tumor elimination, effective metastasis inhibition and high survival rate of tumor-bearing mice after treatment using the Au NTF nanoclusters, indicating that this AIE-guided and tumor-specific synergistic strategy could offer a promising approach for tumor therapy.

关键词： AIE-guided precise tumor treatment copper-dependent photothermal therapy copper-triggered chemodynamic therapy primary tumor elimination copper-plunder-induced metastasis inhibition

Effect of electrolyte cation-mediated mechanism on electrocatalytic carbon dioxide reduction

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Chinese Chemical Letters 2024年第7期35卷 139-146页

作者： Yuan Dong Mutian ma Zhenyang Jiao Sheng Han Likun Xiong Zhao Deng Yang peng Soochow Institute of Energy and material Innovations College of EnergyJiangsu Key Laboratory of Advanced Carbon Materials and Wearable Energy TechnologiesSoochow UniversitySoochow 215006China Jiangsu Key Laboratory of Advanced Negative Carbon Technologies Soochow UniversitySoochow 215123China School of Chemistry and Chemical Engineering Shihezi UniversityShihezi 832003China School of Chemical and Environmental Engineering Shanghai Institute of TechnologyShanghai 201418China

The steep reduction in costs and systematic optimization of renewable electricity has ignited an intensifying interest in harnessing electroreduction of carbon dioxide(CO_(2)RR)for the generation of chemicals and *** focus of research over the past few decades has been on the optimization of the electrode and the electrolyte ***,cation species in the latter have recently been found to dramatically alter the selectivity of CO_(2)RR and even their catalytic activity by multiple orders of *** a result,the selection of cations is a critical factor in designing catalytic interfaces with high selectivity and efficiency for targeted *** decision-making regarding cation selection relies on a comprehensive understanding of prevailing electrolyte effect models that have been used to elucidate observed experimental *** this perspective,we review the hypotheses that explain how electrolyte cations influence CO_(2)RR by mechanisms such as through tuning of the interfacial electric field,buffering of the local pH,stabilization of the key intermediates and regulation of the interfacial *** endeavor is to elucidate the molecular mechanisms underpinning cation effects,thus fostering the evolution of more holistic and universally applicable predictive *** this regard,we highlight the current challenges in this area of research,while also identifying potential avenues for future investigations.

关键词： CO_(2)electrocatalytic reduction Cation effects Catalytic mechanisms Catalytic interfaces Electric double layer

Construction of core@double-shell structured energetic composites with simultaneously enhanced thermal stability and safety performance

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Defence Technology（防务技术） 2024年第4期34卷 134-142页

作者： peng Wang Wen Qian Ruolei Zhong Fangfang He xin Li Jie Chen Li Meng Yinshuang Sun Guansong He Institute of Chemical materials China Academy of Engineering PhysicsMianyang 621900China State Key Laboratory of Environment-friendly Energy materials School of Materials and ChemistrySouthwest University of Science and TechnologyMianyang 621010China

The poor thermal stability and high sensitivity severely hinder the practical application of hexanitrohexaazaisowurtzitane(CL-20).Herein,a kind of novel core@double-shell CL-20 based energetic composites were fabricated to address the above *** coordination complexes which consist of natural polyphenol tannic acid(TA) and Fe~Ⅲ were chosen to construct the inner shell,while the graphene sheets were used to build the outer *** resulting CL-20/TA-Fe~Ⅲ/graphene composites exhibited simultaneously improved thermal stability and safety performance with only 1 wt% double-shell content,which should be ascribed to the intense physical encapsulation effect from inner shell combined with the desensitization effect of carbon nano-materials from outer *** phase transition(ε to γ) temperature increased from 173.70 ℃ of pure CL-20 to 191.87℃ of CL-20/TA-Fe~Ⅲ/graphene ***,the characteristic drop height(H_(50)) dramatically increased from 14.7 cm of pure CL-20 to112.8 cm of CL-20/TA-Fe~Ⅲ/graphene composites,indicating much superior safety performance after the construction of the double-shell *** general,this work has provided an effective and versatile strategy to conquer the thermal stability and safety issues of CL-20 and contributes to the future application of high energy density energetic materials.

关键词： CL-20 Double-shell structure Thermal stability Safety performance Tannic acid Graphene sheets

Rapid Phase Ambiguity Elimination Methods for DOA Estimator via Hybrid massive MIMO Receive Array

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Chinese Journal of Electronics 2024年第1期33卷 175-184页

作者： Xichao ZHAN Zhongwen SUN Feng SHU Yiwen CHEN xin CHENG Yuanyuan WU Qi ZHANG Yifan LI peng ZHANG School of Information and Communication Engineering Hainan University School of Electronic and Optical Engineering Nanjing University of Science and Technology

For a sub-connected hybrid multiple-input multiple-output(MIMO) receiver with K subarrays and N antennas, there exists a challenging problem of how to rapidly remove phase ambiguity in only single time-slot. A direction of arrival(DOA) estimator of maximizing received power(max-RP) is proposed to find the maximum value of K-subarray output powers, where each subarray is in charge of one sector, and the center angle of the sector corresponding to the maximum output is the estimated true DOA. To make an enhancement on precision, max-RP plus quadratic interpolation(max-RP-QI) method is designed. In the proposed max-RP-QI, a quadratic interpolation scheme is adopted to interpolate the three DOA values corresponding to the largest three receive powers of *** achieve the Cramer Rao lower bound, a Root-MUSIC plus max-RP-QI scheme is developed. Simulation results show that the proposed three methods eliminate the phase ambiguity during one time-slot and also show low computational complexities. The proposed Root-MUSIC plus max-RP-QI scheme can reach the Cramer Rao lower bound,and the proposed max-RP and max-RP-QI are still some performance losses 2–4 d B compared to the Cramer Rao lower bound.

关键词： Phased arrays Interpolation Wireless sensor networks Direction-of-arrival estimation Simulation Receiving antennas massive MIMO