检索结果-南通市图书馆

science china Chemistry 2025年第1期68卷 394-402页

作者： Zhiqiang Ding Mingqian Wang Zijing Zhou Bin Wang Yuesheng Li Tianjin Key Laboratory of Composite & Functional Materials School of Materials Science and Engineering Tianjin University

Living/controlled cationic ring-opening polymerization （ROP） of L-lactide is a promising approach to isotactic-rich and crystalline poly（L-lactide）.In contrast with the unsubstituted lactones,L-LA can not be polymerized by organic Lewis acids or carbenium ions,and the state of the art in this field is the cationic ROP of L-LA catalyzed by Br?nsted acid/alcohol system via activated monomer ***,we reported the first example of controlled cationic ROP of L-LA by using Meerweintype ion pair[Me3O]+[B（C6F5）4]-as the catalyst.[Me3O]+[B（C6F5）4]-promoted rapid L-LA cationic polymerization in the absence of alcohol,producing isotactic-rich and crystalline PLLA without transesterification and epimerization side *** activated chain end mechanism,involving twice SN2 substitution and configuration-inversion （S→R→S） with the assistance of released Me2O,was proposed and further verified by density functional theory and control *** work expands the catalytic toolbox of isotactic-rich and crystalline polylactide *** represents a unique example of cationic-controlled polymerization of L-LA catalyzed by an organic ion pair.

关键词： organic ion pair controlled cationic ring-opening polymerization activated chain end mechanism isotactic-rich polylactide

Direct and rapid detection of serum amino acid and monoamine neurotransmitters to assist the diagnosis of panic disorder

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china Chemistry 2025年第1期68卷 377-384页

作者： Shiwen Liu Xuerui Wan Meng Zhao Jiaqi Wang Weilan Wu Linlin You Yonggui Yuan Qian Xu Rong Gao Key Laboratory of Environmental Medicine Engineering Ministry of Education School of Public Health Southeast University Key Laboratory of Modern Toxicology of Ministry of Education Department of Hygienic Analysis and Detection School of Public HealthNanjing Medical University Department of Psychosomatics and Psychiatry Zhongda Hospital School of Medicine Southeast University

The measurement of amino acid and monoamine neurotransmitters（NTs） in serum plays a central role in the identification and monitoring of clinical panic disorder（PD）. However, the strong polarity and chemical heterogeneity of NTs make direct extraction and rapid detection extremely challenging. Herein, we developed a strategy that integrated solid phase extraction based on magnetic Fe3O4coated with polydopamine（Fe3O4@PDA） and direct analysis of mass spectrometry in real time（DART-MS） for quantification of 10 NTs. We systematically investigated the optimal conditions of this strategy to achieve good accuracy and precision. Compared with existing magnetic solid phase extraction methods for NTs detection in biological samples, this strategy could adsorb more targets while having similar adsorption efficiencies, and the total process time was reduced by an average of 69.42%. We rapidly determined the metabolic abnormality of 6 types of NTs in the serum of PD patients and demonstrated their diagnostic accuracy. In addition, an outstanding feature of PD in which tryptophan was more metabolized by the KYN pathway and the 5-hydroxytryptamine pathway was inhibited could be elucidated by this strategy. Our results highlighted the potential ability of Fe3O4@PDA coupled with DART-MS to assist in the clinical diagnosis of PD.

关键词： neurotransmitters panic disorder magnetic solid phase extraction direct analysis of mass spectrometry in real time

Potassium ions and cyano group modified g-C3N4 for effective generation of H2O2 through two-electron oxygen reduction

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china Chemistry 2025年第1期68卷 192-200页

作者： Dongying Wang Shulan Pu Yongmin Chen Ke Lei Yujie Duan Linjiao Mao Xuhui Zeng Xi Luo Yuntao Zhang Yuqin Dong Jin Zhong Zhang Yan Sun School of Mechanical Engineering Chengdu University Department of Chemistry and Biochemistry University of California

Potassium ions （K+） doped graphitic carbon nitride （g-C3N4） was prepared by a thermal etching method using potassium hydroxide （KOH） as an ion *** transform infrared spectroscopy （FTIR） and X-ray photoelectron spectroscopy （XPS）results showed that the generation of the cyano group was detected while introducing K+.Under simulated sunlight irradiation,the sample with a K+doping amount of 10%showed the highest hydrogen peroxide （H2O2） generation rate of2,140.2μmol *** apparent quantum yield （AQY） at 400 nm and the solar-to-chemical conversion （SCC） are 4.35%and1.23%,respectively.K+acted as a bridge between g-C3N4layers,which enhanced charge transfer ***,the cyano group enhanced the adsorption capacity of protons （H+） and promoted the yield of *** catalyst exhibited excellent photocatalytic stability based on four-cycle *** addition,a mechanism study showed that superoxide radicals （·O2-）were the most important active species in the reaction *** production of H2O2was achieved through consecutive single-electron *** study deepens the understanding of the oxygen reduction reaction process and opens up a new venue for improving H2O2generation.

关键词： photocatalysis hydrogen peroxide oxygen reduction reaction potassium doping cyano group

Numerical Simulation of Radiation Transport to Improve Microalgae Cultivation in an Air-Lift Photobioreactor

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Thermal science 2025年第1期34卷 62-76页

作者： ZHANG Xianbin LI Mingjia HUNG Tzuchen ZHANG Zixun Key Laboratory of Thermo-Fluid science and Engineering of Ministry of Education School of Energy and Power EngineeringXi'an Jiaotong University School of Mechanical Engineering Beijing Institute of Technology Department of Mechanical Engineering Taipei University of Technology

A comprehensive numerical model is developed to simulate the growth of microalgae under light/dark cycling *** purpose of this study is to predict the growth rate of Chlorella vulgaris cultivated in photobioreactors(PBRs) in order to improve the light conditions for microalgae and enhance the photosynthetic *** fluid dynamics(CFD) is used to simulate its internal hydrodynamic *** Lagrangian method is employed to track the movement of microalgae *** radiative transfer equation(RTE)is used to obtain light intensity *** combination of light radiation field and microalgae cell motions is used to construct the light history and they are integrated into the model of the photosynthetic units(PSU) to calculate the microalgae growth *** numerical results demonstrate that enhanced light/dark cycling frequency with ordered mixing can promote efficient microalgae *** effect of the vortex flow field generated by the baffles in an air-lift PBR is analyzed for increasing microalgae growth *** using the 1:1 baffle spacing,the biomass production of microalgae is increased by 41.8% compared to the original PBR.

关键词： light distribution particle tracking photobioreactor structure optimization

Separation of the ionospheric and thermospheric contributions in the data from the Triple Ionosophere Photo Meter onboard the Feng-Yun 3E satellite

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china Earth sciences 2025年第1期68卷 172-184页

作者： Fang JIANG Tian MAO Jin-Song WANG Xiu-Qing HU Xiao-Xin ZHANG Liping FU Nan JIA Tianfang WANG national Space science Center Chinese Academy of Sciences Beijing Key Laboratory of Space Environment Exploration Key Laboratory of Environmental Space Situation Awareness Technology national Satellite Meteorological Center China Meteorological Administration

The Triple Ionosphere Photo Meter （TRIPM） is a far ultraviolet nadir-view photometer that is onboard the secondgeneration,polar-orbiting Chinese meteorological satellite Feng-Yun 3E （FY-3E）,which was launched on July 5,*** has three channels,and each is used to measure different types of emissions:（1） 135.6 nm airglow produced by the recombination of the O+ions and electrons in the absence of sunlight （nighttime channel）;（2） 135.6 nm airglow from the OI when sunlight is present （daytime/dusk-dawn 135.6 nm channel）;and （3） Airglow in the N2LBH of the TRIPM （daytime/dusk-dawn N2LBH channel）.FY-3E is a satellite operating in the early morning ***,the data are mostly distributed on the dawndusk side or at times when the solar zenith angle is relatively *** this study,combined with simulation calculations,the data are *** further explore the application value of the data products,a model is used to separate the ionospheric radiative recombination contribution from the thermosphere photoelectron impact excitation contribution in the data from the daytime/dusk-dawn 135.6 nm *** approach not only improves the accuracy of O/N2derived from the 135.6 nm channel and N2LBH channel but also provides the ionospheric 135.6 nm radiance at the same time as the *** results show that the 135.6 nm radiance originating from the combination of O+and electrons extracted from the measurement data exhibits similar equatorial anomaly peak structure characteristics and seasonal variations as the corresponding GPS total electron content （TEC） *** the other hand,the separated 135.6 nm radiance generated from the thermosphere photoelectron collision excitation does not contain radiative recombination contributions;thus,the ionosphere influence is greatly avoided when the O/N2is obtained.

关键词： Far ultraviolet 135.6 nm emission intensity Photoelectron impact excitation Radiative recombination excitation

同方期刊数据库

Effect of order–disorder transition on thermodynamic and electronic properties of σ and χ phases in W–Re alloy: the first-principles calculation

在线全文

学校读者我要写书评

暂无评论

Tungsten 2025年第1期7卷 195-213页

作者： Zhi-Peng Zhu Dian Jia William Yi Wang Jun-Lei Yin Xing-Yu Gao Shu-Feng Yang Hai-Feng Song Jin-Shan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical University Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The Tungsten-Rhenium(W-Re) alloys,celebrated for their high melting point,strength at elevated temperatures,electrical resistivity,and radiation resistance,have been widely utilized in high-temperature components,aerospace,electronics,and nuclear *** constituents of the topologically close-packed(TCP) phases,the sigma phase(σ) and chi phase(χ) formed within W-Re alloys wield considerable influence on the mechanical properties and the stability of the *** calculations were utilized in the present work to explore the structural,thermodynamic,and electronic properties of both ordered and disordered configurations within the σ and χ phases,culminating in a systematic elucidation of the higher phase stability exhibited by the ordered *** is found that the bulk modulus of these two phases is directly proportional to the concentration of Re in the alloy,while the equilibrium volume is inversely *** thermodynamic parameters of the σ and χ phases are calculated via the mean-field potential *** similar trends observed in the isobaric heat capacity,enthalpy increment,and entropy change curves for these two phases suggest they possess comparable thermodynamic *** is noteworthy that the contribution of ionic vibrations predominantly affects the isobaric heat capacity,while the contribution of thermal electronic excitations increases linearly with *** the structure and thermodynamic properties of TCP phases in W-Re alloys at low temperatures has profound significance for optimizing material performance,microstructures features,establishing theoretical foundations,and predicting material behavior.

关键词： First-principles calculations Phase stability TCP phases Thermodynamic properties W–Re alloy

Late Paleozoic to early Mesozoic volcanic-sedimentary history of the southeastern margin of the Central Asian Orogenic Belt: Timing of uplift of the Inner Mongolia paleo-uplift

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china Earth sciences 2025年第1期68卷 297-309页

作者： Wenxing HAO Jin-Hui YANG Guang ZHU State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences School of Resource and Environmental Engineering Hefei University of Technology

The Kulun region is located in the eastern Bainaimiao arc belt on the southeastern margin of the Central Asian Orogenic Belt(CAOB), adjacent to the North china Craton(NCC) to the south. This region records the closure of the PaleoAsian Ocean during the Paleozoic to early Mesozoic and is key to study the tectonic evolution of the northern margin of the *** conducted zircon U-Pb geochronology and Hf isotope analysis of volcanic-sedimentary and intrusive rocks in the Kulun region. The volcanic-sedimentary rocks were previously assigned an early Carboniferous age, but include volcanic rocks with ages of 267–266 Ma and sedimentary rocks with youngest detrital zircon age peaks of 265–244 Ma, which were intruded by a granite with an age of 242 Ma. This indicates that these rocks are actually middle Permian to Middle Triassic in age(267–242Ma) and correspond to the Qingfengshan and Liujiagou formations. Moreover, two volcanic rock samples have high εHf(t) values(+1.6 to +16.1) and relatively young two-stage Hf model ages(1095–327 Ma), indicating their sources associated with the CAOB. The age spectra and Hf isotopic characteristics of detrital zircons from the sedimentary rocks suggest that, during the middle Permian to Middle Triassic, the sedimentary provenance in the Kulun region was mainly the CAOB. However, by the Early Jurassic, the provenance changed to the NCC(i.e., the Inner Mongolia Paleo-uplift, IMPU). This result, combined with the development of a series of conglomerates on the northern margin of the NCC in the Late Triassic(i.e., Xingshikou, Xiaoyingzi,and Xiaohekou formations), indicates the Kulun region experienced an abrupt change in paleogeography during the Late Triassic, with the IMPU undergoing significant uplift and thus becoming the main sediment source in the Kulun region. Based on the Late Triassic alkaline igneous belt(235–215 Ma) in the IMPU, we speculate that this uplift was caused by detachment of the southward-subducting Paleo-Asian oceanic

关键词： Central Asian Orogenic Belt the North china Craton Zircon geochronology Hf isotopes Inner Mongolia Paleo-uplift

Local magnetic moment oscillation around an Anderson impurity on graphene

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 192-201页

作者： Shuai Li Zhen Ma Jin-Hua Gao School of science Hebei University of Science and Technology School of Electronics and Information Zhengzhou University of Light Industry School of Physics and Wuhan national High Magnetic Field Center Huazhong University of Science and Technology

We theoretically investigate the spin resolved Friedel oscillation （FO） and quasiparticle interference （QPI） in graphene induced by an Anderson *** the impurity becomes magnetic,the resulted FO becomes spin dependent,which gives rise to a local magnetic moment oscillation with an envelop decaying as r-2in real space in the doping ***,at half filling,the electron density and local magnetic moment will not oscillate but decay as *** spin resolved FO has both sublattice and spin ***,the local magnetic moment decay at half filling only occurs at one sublattice of graphene,which is quite like the phenomenon observed in the STM experiment (***ález-Herrero et al.,science 352,437 （2016）).We further give an analytic formula about such spin dependent FO based on the stationary phase ***,we study the interference of quasiparticles around the magnetic impurity by calculating the spin dependent Fourier-transformed local density of states （FT-LDOS）.Our work gives a comprehensive understanding about the local magnetic moment oscillation around an Anderson impurity on graphene.

关键词： Friedel oscillation local magnetic moment graphene Anderson impurity

Reducing the measurement errors in nonadiabatic holonomic quantum computers

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 64-70页

作者： Guo-Fu Xu Department of Physics Shandong University

Nonadiabatic holonomic quantum computers serve as the physical platform for nonadiabatic holonomic quantum *** quantum computation has entered the noisy intermediate-scale era, building accurate intermediate-scale nonadiabatic holonomic quantum computers is clearly necessary. Given that measurements are the sole means of extracting information, they play an indispensable role in nonadiabatic holonomic quantum computers. Accordingly, developing methods to reduce measurement errors in nonadiabatic holonomic quantum computers is of great importance. However, while much attention has been given to the research on nonadiabatic holonomic gates, the research on reducing measurement errors in nonadiabatic holonomic quantum computers is severely lacking. In this study, we propose a measurement error reduction method tailored for intermediate-scale nonadiabatic holonomic quantum computers. The reason we say this is because our method can not only reduce the measurement errors in the computer but also be useful in mitigating errors originating from nonadiabatic holonomic gates. Given these features,our method significantly advances the construction of accurate intermediate-scale nonadiabatic holonomic quantum computers.

关键词： quantum holonomy quantum computation measurement errors

Nanograting‑Based Dynamic Structural Colors Using Heterogeneous Materials

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第3期17卷 138-151页

作者： Jingang Wang Haibo Yu Jianchen Zheng Yuzhao Zhang Hongji Guo Ye Qiu Xiaoduo Wang Yongliang Yang Lianqing Liu State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110016People’s Republic of China University of Chinese Academy of sciences Beijing 100049People’s Republic of China

Dynamic structuralcolors can change in response todifferent environmental *** ability remains effectiveeven when the size of the speciesresponsible for the structural coloris reduced to a few micrometers,providing a promising sensingmechanism for solving microenvironmentalsensing problems inmicro-robotics and ***, the lack of dynamicstructural colors that can encoderapidly, easily integrate, and accuratelyreflect changes in physical quantities hinders their use in microscale sensing applications. Herein, we present a 2.5-dimensionaldynamic structural color based on nanogratings of heterogeneous materials, which were obtained by interweaving a pH-responsive hydrogelwith an IP-L photoresist. Transverse gratings printed with pH-responsive hydrogels elongated the period of longitudinal grating in the swollenstate, resulting in pH-tuned structural colors at a 45° incidence. Moreover, the patterned encoding and array printing of dynamic structuralcolors were achieved using grayscale stripe images to accurately encode the periods and heights of the nanogrid structures. Overall, dynamicstructural color networks exhibit promising potential for applications in information encryption and in situ sensing for microfluidic chips.

关键词： Dynamic structural colors Four-dimensional printing pH-responsive Nanogrid Heterogeneous materials

维普期刊数据库