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Strong gravitational lensing constraints on holographic dark energy

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Science China(Physics,Mechanics & Astronomy) 2015年第11期58卷 68-74页

作者： CUI JingLei XU YueYao zhang jingfei zhang Xin Department of Physics College of Sciences Northeastern University Center for High Energy Physics Peking University

Strong gravitational lensing(SGL) has provided an important tool for probing galaxies and cosmology. In this paper, we use the SGL data to constrain the holographic dark energy model, as well as models that have the same parameter number, such as the w CDM and Ricci dark energy models. We find that only using SGL is difficult to effectively constrain the model ***, when the SGL data are combined with CBS(CMB+BAO+SN) data, the reasonable estimations can be given and the constraint precision is improved to a certain extent, relative to the case of CBS only. Therefore, SGL is an useful way to tighten constraints on model parameters.

关键词： cosmological constraints strong gravitational lensing holographic dark energy

Tilt of primordial gravitational wave spectrum in a universe with sterile neutrinos

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Science China(Physics,Mechanics & Astronomy) 2014年第8期57卷 1455-1459页

作者： Li YunHe zhang jingfei zhang Xin Department of Physics College of Sciences Northeastern University Center for High Energy Physics Peking University

In this work, we constrain the spectral index nt of the primordial gravitational wave power spectrum in a universe with sterile neutrinos by using the Planck temperature data, the WMAP 9-year polarization data, the baryon acoustic oscillation data, and the BICEP2 data. We call this model the ACDM＋r＋vs＋nt model. The additional massive sterile neutrino species can significantly relieve the tension between the Planck and BICEP2 data, and thus can reduce the possible effects of this tension on the fit results of nt. To constrain the parameters of sterile neutrino, we also utilize the Hubble constant direct measurement data, the Planck Sunyaev-Zeldovich cluster counts data, the Planck CMB lensing data, and the cosmic shear data. We find that due to the fact that the BICEP2 data are most sensitive to the multipole （ - 150 corresponding to k - 0.01 Mpc^-1, there exists a strong anticorrelation between nt and r0.0o2 in the BICEP2 data, and this further results in a strongly blue-tilt spectrum. However, a slightly red-tilt tensor power spectrum is also allowed by the BICEP2 data in the region with larger value of r0.00z. By using the full data sets, we obtain mvisterile ^eff = 0.48 -0.13^＋0.11 eV, Near = 3.73 -0.37^＋0.34, and nt = 0.96 -0.63^ ＋0.48 for the ACDM＋r＋vs＋nt model.

关键词： primordial gravitational waves BICEP2 sterile neutrino tilt of tensor power spectrum

Dark energy versus modified gravity: Impacts on measuring neutrino mass

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Science China(Physics,Mechanics & Astronomy) 2020年第3期63卷 44-53页

作者： MingMing Zhao RuiYun Guo DongZe He jingfei zhang Xin zhang Department of Physics College of SciencesNortheastern UniversityShenyang 110819China Ministry of Education’s Key Laboratory of Data Analytics and Optimization for Smart Industry Northeastern UniversityShenyang 110819China Center for High Energy Physics Peking UniversityBeijing 100080China

In this paper,we make a comparison for the impacts of smooth dynamical dark energy,modified gravity,and interacting dark energy on the cosmological constraints on the total mass of active *** definiteness,we consider theΛCDM model,the w CDM model,the f(R)model,and two typical interacting vacuum energy models,i.e.,the IΛCDM1 model with Q=βHρc and the IΛCDM2 model with Q=βHρΛ.In the cosmological fits,we use the Planck 2015 temperature and polarization data,in combination with other low-redshift observations including the baryon acoustic oscillations,the type Ia supernovae,the Hubble constant measurement,and the large-scale structure observations,such as the weak lensing as well as the redshift-space ***,the Planck lensing measurement is also employed in this *** find that,the w CDM model favors a higher upper limit on the neutrino mass compared to theΛCDM model,while the upper limit in the f(R)model is similar with that in theΛCDM *** the interacting vacuum energy models,the IΛCDM1 model favors a higher upper limit on neutrino mass,while the IΛCDM2 model favors an identical neutrino mass with the case ofΛCDM.

关键词： neutrino mass dark energy modified gravity interacting dark energy cosmological observations

Revisiting the interacting model of new agegraphic dark energy

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Science China(Physics,Mechanics & Astronomy) 2014年第2期57卷 387-392页

作者： zhang jingfei ZHAO LiAng zhang Xin College of Sciences Northeastern University Center for High Energy Physics Peking University

In this paper, a new version of the interacting model of new agegraphic dark energy （INADE） is proposed and analyzed in detail. The interaction between dark energy and dark matter is reconsidered. The interaction term Q = bh0ραdcρ1-α dm is adopted, which abandons the Hubble expansion rate H and involves both Pae and Pare. Moreover, the new initial condition for the agegraphie dark energy is used, which solves the problem of accommodating baryon matter and radiation in the model. The solution of the model can be given using an iterative algorithm. A concrete example for the calculation of the model is given. Furthermore, the model is constrained by using the combined Planck data （Planck＋BAO＋SNIa＋H0） and the combined WMAP-9 data （WMAP＋BAO＋SNIa＋H0）. Three typical cases are considered：（A） Q = bHoPde, （B） Q = bHo√ρdeρdm,and （C） Q = bHopdm, which correspond to α = 1, 1/2, and 0, respectively. The departures of the models from the ACDM model are measured by the ABIC and AAIC values. It is shown that the INADE model is better than the NADE model in the fit, and the 1NADE（A） model is the best in fitting data among the three cases.

关键词： agegraphic dark energy interacting dark energy model Planck data

Dietary dimethylglycine sodium salt supplementation alleviates redox status imbalance and intestinal dysfunction in weaned piglets with intrauterine growth restriction

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Animal Nutrition 2022年第3期10卷 188-197页

作者： Kaiwen Bai Luyi Jiang Qiming Li jingfei zhang Lili zhang Tian Wang College of Animal Science and Technology Nanjing Agricultural UniversityNanjingChina College of Animal Science Zhejiang UniversityHangzhouChina

There are few studies on the mechanism of redox status imbalance and intestinal dysfunction in intrauterine growth restricted(IUGR)newborn ***,we investigated the mechanism of jejunum dysfunction in weaned piglets with IUGR and the mechanism through which dimethylglycine sodium salt(DMG-Na)supplementation improving the imbalance of their redox *** this work,a total of 10 normal birth weight(NBW)newborn piglets and 20 IUGR newborn piglets were *** weaning at 21 d,they were assigned to 3 groups(n=10/group):NBW weaned piglets fed standard basal diets(NBWC);one IUGR weaned piglets fed standard basal diets(IUGRC);another IUGR weaned piglets from the same litter fed standard basal diets plus 0.1%DMG-Na(IUGRD).The piglets in these 3 groups were sacrificed at 49 d of age,and the blood and jejunum samples were collected *** growth performance values in the IUGRC group were lower(P<0.05)than those in the NBWC *** histomorphological parameters,inflammatory cytokines,and digestive enzyme activity as well as serum immunoglobulin were lower(P<0.05)in the IUGRC group than those in the NBWC *** with these in the NBWC group,the redox status of serum,jejunum,and mitochondria and the expression levels of jejunum redox status-related,cell adhesion-related,and mitochondrial function-related genes and proteins were suppressed in the IUGRC group(P<0.05).However,compared with those in the IUGRC group,the growth performance values,jejunum histomorphological parameters,inflammatory cytokines,digestive enzyme activity,serum immunoglobulin,redox status of serum,jejunum,and mitochondria,and the expression levels of jejunum redox status-related,cell adhesion-related,and mitochondrial function-related genes and proteins were improved(P<0.05)in the IUGRD *** conclusion,dietary DMG-Na supplementation alleviates redox status imbalance and intestinal dysfunction in IUGR weaned piglets mainly by activating the sirtuin 1(SIRT1)/peroxisome

关键词： Intrauterine growth restriction Weaned piglet Jejunum Redox status Mitochondrial function Dimethylglycine sodium salt

Research on the feasibility of storage and estimation model of storage capacity of CO_(2)in fissures of coal mine old goaf

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International Journal of Mining Science and Technology 2023年第6期33卷 675-686页

作者： Yang Ding Shugang Li Bing Zhu Haifei Lin jingfei zhang Junhong Tan Wenbin Chen School of Safety Science and Engineering Xi’an University of Science and TechnologyXi’an 710054China Western Coal Gas Intelligent Draining Engineering Research Center China National Coal AssociationXi’an 710054China

The concept of the carbon cycle in the old goaf of a coal mine based on CO_(2)utilization and storage was put forward adhering to the principle of low-carbon development,utilization of space resources in old goafs,and associated gas resources ***,the evolution characteristics of overburden fissures in the goaf of the case was studied using a two-dimensional physical similarity simulation test,the sealing performance of the caprocks after stabilization was analyzed,and the fissures were counted and ***,the process of gaseous CO_(2)injection in the connected fissure was simulated by Ansys Fluent software,and the migration law and distribution characteristics of CO_(2)under the condition of gaseous CO_(2)injection were ***,the estimation models of free CO_(2)storage capacity in the old goaf were constructed considering the proportion of connected fissure and the effectiveness of CO_(2)*** CO_(2)storage capacity in the old goaf of the case coal mine was *** results showed that a caprock group of“hard-thickness low-permeability hard-thickness”was formed after the caprock-fissures system in the goaf of the case tended to be stable *** connected fissure,occlude cracks,and micro-fractures in the goaf accounted for 85.5%,8.5%,and 6%of the total fissures,*** CO_(2)first migrated to the bottom of the connected fissure after CO_(2)was injected into the goaf,then spread horizontally along the bottom of the connected fissure after reaching the bottom,and finally spread longitudinally after filling the bottom of the entire connected *** theoretical and effective storage capacities of free CO_(2)at normal temperature and pressure in the old goaf of the case were 9757 and 7477 t,*** effective storage capacity of free CO_(2)at normal temperature and pressure in the old goaf after all minefield mined was 193404 *** research can provide some reference for the coal mining ind

关键词： Carbon cycle Old goaf Fissure CO_(2)storage Feasibility Storage capacity

Spinel MnCo2O4 nanoparticles cross-linked with two-dimensional porous carbon nanosheets as a high-efficiency oxygen reduction electrocatalyst

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Nano Research 2016年第7期9卷 2110-2122页

作者： Gengtao Fu Zhenyuan Liu jingfei zhang Jiayan Wu Lin Xu Dongmei Sun Jubing zhang Yawen Tang Pei Chen Jiangsu Key Laboratory of New Power Batteries Jiangsu Collaborative Innovation Centre of Biomedical Functional Materials School of Chemistry and Materials Science Nanjing Normal University Nanjing 210023 China Key Laboratory of Applied Surface and Colloid Chemistry (MOE) School of Materials Science and Engineering Shaanxi Normal University Xi'an 710062 China Materials Science and Engineering Program & Texas Materials Institute the University of Texas atAustin Austin Texas 78712 USA

Catalysts for the oxygen reduction reaction （ORR） play an important role in fuel cells. Alternative non-precious metal catalysts with comparable ORR activity to Pt-based catalysts are highly desirable for the development of fuel cells. In this work, we report for the first time a spinel MnC0204/C ORR catalyst consisting of uniform MnC0204 nanoparticles cross-linked with two-dimensional （2D） porous carbon nanosheets （abbreviated as porous MnC0204/C nanosheets）, in which glucose is used as the carbon source and NaC1 as the template. The obtained porous MnCo204/C nanosheets present the combined properties of an interconnected porous architecture and a large surface area （175.3 m2-g-1）, as well as good electrical conductivity （1.15 x 102 ***-1）. Thus, the as-prepared MnC0204/C nanosheets efficiently facilitate electrolyte diffusion and offer an expedite transport path for reactants and electrons during the ORR. As a result, the as-prepared porous MnC0204/C nanosheet catalyst exhibits enhanced ORR activity with a higher onset potential and current density than those of its counterparts, including pure MnC0204, carbon nanosheets, and Vulcan XC-72R carbon. More importantly, the porous MnC0204/C nanosheets exhibit a com- parable electrocatalytic activity but superior stability and tolerance toward methanol crossover effects than a high-performance Pt/C catalyst in alkaline medium. The synthetic strategy outlined here can be extended to other non- precious metal catalysts for application in electrochemical energy conversion.

关键词： spinel SnCo2O4 carbon porous nanosheets electrocatalysis oxygen reduction reaction

Proline-derived in situ synthesis of nitrogen-doped porous carbon nanosheets with encaged Fe203@Fe3C nanoparticles for lithium-ion battery anodes

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Nano Research 2017年第9期10卷 3164-3177页

作者： jingfei zhang Lijuan Qi Xiaoshu Zhu Xiaohong Yan Yufeng Jia Lin Xu Dongmei Sun Yawen Tang Jiangsu Key Laboratory of New Power Batteries _llangsu Collaborative Innovation Center of Biomedical FunctionaI Materials Analysisand Testing Center School of Chemistry and Materials Science Nanjing Normal University Nanjing 210023 China

The homogeneous incorporation of heteroatoms into two-dimensional C nanostructures, which leads to an increased chemical reactivity and electrical conductivity as well as enhanced synergistic catalysis as a conductive matrix to disperse and encapsulate active nanocatalysts, is highly attractive and quite challenging. In this study, by using the natural and cheap hydrotropic amino acid proline—which has remarkably high solubility in water and a desirable N content of ~12.2 wt.%—as a C precursor pyrolyzed in the presence of a cubic KCl template, we developed a facile protocol for the large-scale production of N-doped C nanosheets with a hierarchically porous structure in a homogeneous dispersion. With concomitantly encapsulated and evenly spread Fe2O3 nanoparticles surrounded by two protective ultrathin layers of inner Fe3C and outer onion-like C, the resulting N-doped graphitic C nanosheet hybrids (Fe2O3@Fe3C-NGCNs) exhibited a very high Li-storage capacity and excellent rate capability with a reliable and prolonged cycle life. A reversible capacity as high as 857 mAh•g–1 at a current density of 100 mA•g–1 was observed even after 100 cycles. The capacity retention at a current density 10 times higher—1,000 mA•g–1—reached 680 mAh•g–1, which is 79% of that at 100 mA•g–1, indicating that the hybrids are promising as anodes for advanced Li-ion batteries. The results highlight the importance of the heteroatomic dopant modification of the NGCNs host with tailored electronic and crystalline structures for competitive Li-storage features.

关键词： proline N-doped C nanosheet porous encaged Fe_2O_3@Fe_3C Li-ion battery

“留有余地”与“寻求合作”:中美地震科技交流(1971—1979)

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自然科学史研究 2021年第1期40卷 77-90页

作者：张井飞中国科学院自然科学史研究所北京100190 中国科学院大学北京100049

20世纪70年代,在中美关系正常化的进程中,科技交流先行,既推动着两国政治关系的发展,又深受两国政治关系的制约。中美科技水平悬殊,地震预报是当时为数不多的双方各有所长、优势互补的领域之一,成为两国科技交流的一个焦点。20多年的隔... 详细信息

20世纪70年代,在中美关系正常化的进程中,科技交流先行,既推动着两国政治关系的发展,又深受两国政治关系的制约。中美科技水平悬殊,地震预报是当时为数不多的双方各有所长、优势互补的领域之一,成为两国科技交流的一个焦点。20多年的隔绝,致使中美地震学界的交流阻碍重重,双方的态度也截然不同。美方在积极进行交流的同时,努力寻求开展实质性的中美地震科技合作,而中方始终以“既要积极宣传,又不要自吹自擂,要留有余地”为原则,并坚持在两国建交之前不进行正式合作。中美双方地震学界的交流是建交前中美关系的一个缩影。文章通过梳理中美地震预报交流的过程,剖析交流中的细节与具体问题,折射科技交流与政治、外交的复杂关系。

关键词：地学史地震预报科技交流中美建交