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Symmetry energy of strange quark matter and tidal deformability of strange quark stars

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Nuclear Science and Techniques 2022年第11期33卷 89-100页

作者： jian-feng xu Cheng-Jun Xia Zhen-Yan Lu Guang-Xiong Peng Ya-Peng Zhao College of Information Engineering Suqian UniversitySuqian 223800China School of Physics and Electrical Engineering AnYang Normal UniversityAnyang 455000China Center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials School of Physics and ElectronicsHunan University of Science and TechnologyXiangtan 411201China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Institute of High-Energy Physics Chinese Academy of SciencesBeijing 100049China School of Mathematics and Physics Henan Urban Construction UniversityPingdingshan 467036China

Research performed during the past decade revealed an important role of symmetry energy in the equation of state(EOS)of strange quark matter(SQM).By introducing an isospin-dependent term into the quark mass scaling,the SQM stability window in the equivparticle model was studied.The results show that a sufficiently strong isospin dependence C_(I)can significantly widen the SQM region of absolute stability,yielding results that simultaneously satisfy the constraints of the astrophysical observations of PSR J1614-2230 with 1.928±0.017 Mand tidal deformability 70≤Λ_(1:4)≤580 measured in the event GW170817.With increasing C_(I),the difference between the u,d,and s quark fractions for the SQM inβ-equilibrium becomes inconspicuous for C>0,leading to small isospin asymmetryδ,and further resulting in similar EOS and structures of strange quark stars(SQSs).Moreover,unlike the behavior of the maximum mass of ud QSs,which varies with C_(I)depending on the sign of the parameter C,the maximum mass of the SQSs decreases monotonously with increasing CI.

关键词： Symmetry energy Strange quark matter Strange stars Tidal deformability

Bulk viscosity of interacting magnetized strange quark matter

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Nuclear Science and Techniques 2021年第10期32卷 101-109页

作者： jian-feng xu School of Physics and Electrical Engineering AnYang Normal UniversityAnyang 455000China

The bulk viscosity of interacting strange quark matter in a strong external magnetic field B m with a real equation of state is investigated.It is found that interquark interactions can significantly increase the bulk viscosity,and the magnetic field B_(m) can cause irregular oscillations in both components of the bulk viscosity,ξ||(parallel to B_(m))and ξ⊥(perpendicular to B_(m)).A comparison with non-interacting strange quark matter reveals that when B_(m) is sufficiently large,ξ⊥is more affected by interactions than ξ||.Additionally,the quasi-oscillation of the bulk viscosity with changes in density may facilitate the for-mation of magnetic domains.Moreover,the resulting r-mode instability windows are in good agreement with observational data for compact stars in low-mass X-ray binaries.Specifically,the r-mode instability window for interacting strange quark matter in high magnetic fields has a minimum rotation frequency exceeding 1050 Hz,which may explain the observed very high spin frequency of a pulsar with V=1122 Hz.

关键词： Strange quark matter Bulk viscosity Strong magnetic field Strange star R-mode instability window

GPU-accelerated three-dimensional reconstruction method of the Compton camera and its application in radionuclide imaging

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Nuclear Science and Techniques 2023年第4期34卷 54-68页

作者： Ren-Yao Wu Chang-Ran Geng feng Tian Zhi-Yang Yao Chun-Hui Gong Hao-Nan Han jian-feng xu Yong-Shun Xiao Xiao-Bin Tang Department of Nuclear Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Engineering Physics Tsinghua UniversityBeijing 100084China School of Environmental and Biological Engineering Nanjing University of Science and TechnologyNanjing 210094China JYAMS PET Research and Development Limited Nanjing 211100China

A novel and fast three-dimensional reconstruction method for a Compton camera and its performance in radionuclide imaging is proposed and analyzed in this study. The conical surface sampling back-projection method with scattering angle correction(CSS-BP-SC) can quickly perform the back-projection process of the Compton cone and can be used to precompute the list-mode maximum likelihood expectation maximization(LM-MLEM). A dedicated parallel architecture was designed for the graphics processing unit acceleration of the back-projection and iteration stage of the CSS-BP-SC-based LM-MLEM. The imaging results of the two-point source Monte Carlo(MC) simulation demonstrate that by analyzing the full width at half maximum along the three coordinate axes, the CSS-BP-SC-based LM-MLEM can obtain imaging results comparable to those of the traditional reconstruction algorithm, that is, the simple back-projection-based LM-MLEM. The imaging results of the mouse phantom MC simulation and experiment demonstrate that the reconstruction results obtained by the proposed method sufficiently coincide with the set radioactivity distribution, and the speed increased by more than 664 times compared to the traditional reconstruction algorithm in the mouse phantom experiment. The proposed method will further advance the imaging applications of Compton cameras.

关键词： Compton camera Three-dimensional reconstruction Radionuclide imaging GPU

Properties of quark matter in a new quasiparticle model with QCD running coupling

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Science China(Physics,Mechanics & Astronomy) 2016年第6期59卷 49-57页

作者： Zhen Yan Lu Guang Xiong Peng jian feng xu Shi Peng Zhang School of Physical Sciences University of Chinese Academy of Sciences Theoretical Physics Center for Science Facilities Institute of High Energy Physics

The running of the QCD coupling in the effective mass causes thermodynamic inconsistency problem in the conventional quasiparticle model. We provide a novel treatment which removes the inconsistency by an effective bag constant. The chemical potential dependence of the renormalization subtraction point is constrained by the Cauchy condition in the chemical potential space. The stability and microscopic properties of strange quark matter are then studied within the completely self-consistent quasiparticle model, and the obtained equation of state of quark matter is applied to the investigation of strange stars. It is found that our improved model can describe well compact stars with mass about two times the solar mass, which indicates that such massive compact stars could be strange stars.

关键词：奇异夸克物质粒子模型 QCD 物质性质耦合恒星质量一致性问题有效质量

Spatiotemporal patterns of non-point source nitrogen loss in an agricultural catchment

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Water Science and Engineering 2016年第2期9卷 125-133页

作者： jian-feng xu Wei Yin Lei Ai Xiao-kang Xin Zhi-hua Shi College of Resources and Environment Huazhong Agricultural University Wuhan 430070 China Changjiang Water Resources Protection Institute Wuhan 430051 China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationChinese Academy of Sciences Yangling 712100 China

Non-point source nitrogen loss poses a risk to sustainable aquatic ecosystems. However, non-point sources, as well as impaired river segments with high nitrogen concentrations, are difficult to monitor and regulate because of their diffusive nature, budget constraints, and resource deficiencies. For the purpose of catchment management, the Bayesian maximum entropy approach and spatial regression models have been used to explore the spatiotemporal patterns of non-point source nitrogen loss. In this study, a total of 18 sampling sites were selected along the river network in the Hujiashan Catchment. Over the time period of 2008e2012, water samples were collected 116 times at each site and analyzed for non-point source nitrogen loss. The morphometric variables and soil drainage of different land cover types were studied and considered potential factors affecting nitrogen loss. The results revealed that, compared with the approach using the Euclidean distance, the Bayesian maximum entropy approach using the river distance led to an appreciable 10.1% reduction in the estimation error, and more than 53.3% and 44.7% of the river network in the dry and wet seasons, respectively, had a probability of non-point source nitrogen impairment. The proportion of the impaired river segments exhibited an overall decreasing trend in the study catchment from 2008 to 2012, and the reduction in the wet seasons was greater than that in the dry seasons. High nitrogen concentrations were primarily found in the downstream reaches and river segments close to the residential lands. Croplands and residential lands were the dominant factors affecting non-point source nitrogen loss, and explained up to 70.7%of total nitrogen in the dry seasons and 54.7% in the wet seasons. A thorough understanding of the location of impaired river segments and the dominant factors affecting total nitrogen concentration would have considerable importance for catchment management.

关键词： Non-point source nitrogen Bayesian maximum entropy River distance Spatial regression Spatiotemporal pattern

Blood eosinophils and mortality in patients with acute respiratory distress syndrome: A propensity score matching analysis

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World Journal of Emergency Medicine 2021年第2期12卷 131-136页

作者： Hao-tian Chen jian-feng xu Xiao-xia Huang Ni-ya Zhou Yong-kui Wang Yue Mao Department of Emergency Intensive Care Unit the Second Affi liated Hospital of Zhejiang University School of MedicineHangzhou 310009China Department of Respiratory Therapy the Second Affi liated Hospital of Zhejiang University School of MedicineHangzhou 310009China Department of Respiratory Medicine the Second Affi liated Hospital of Zhejiang University School of MedicineHangzhou 310009China Department of Medical Administration the Second Affi liated Hospital of Zhejiang University School of MedicineHangzhou 310009China Department of Cardiology the Second Affi liated Hospital of Zhejiang University School of MedicineHangzhou 310009China

BACKGROUND: The effect of blood eosinophils(EOSs) on mortality in acute respiratory distress syndrome(ARDS) patients and whether corticosteroids affect this effect are unclear.METHODS: The Medical Information Mart for Intensive Care III database(version 1.4) was used to extract data. Patients with ARDS were selected for inclusion. Cox regression models using the backward stepwise method and propensity score matching(PSM) were used to assess the relationship between blood EOS counts and 28-day mortality. RESULTS: A total of 2,567 patients with ARDS were included, and the 28-day mortality rate was 24.19%. The crude 28-day mortality was significantly lower in patients with EOS counts ≥2%(18.60% [85/457] vs. 25.40% [536/2,110], P=0.002) than in those with EOS counts <2%. In the Cox regression model, the EOS counts ≥2% showed a significant association with the decreased 28-day mortality(hazard ratio [HR] 0.731;95% confidence interval [95% CI] 0.581–0.921, P=0.008). In the corticosteroid non-use subgroup, EOS counts ≥2% was significantly related to decreased 28-day mortality(HR 0.697, 95% CI 0.535–0.909, P=0.008), but the result was not significant in the corticosteroid non-use subgroup model(P=0.860). A total of 457 well-matched pairs were obtained by a 1:1 matching algorithm after PSM. The 28-day mortality remained significantly lower in the EOS counts ≥2% group(18.60% [85/457] vs. 26.70% [122/457], P=0.003).CONCLUSIONS Higher EOS counts are related to lower 28-day mortality in ARDS patients, and this relationship can be counteracted by using corticosteroids.

关键词： Critical care Acute respiratory distress syndrome Eosinophils Mortality Corticosteroid

Regio- and stereo-selective synthesis of multi-substituted 3-pyrrolines

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Chinese Chemical Letters 2009年第9期20卷 1015-1016页

作者： jian feng xu Peng Bin Li Lu Ling Wu Xian Huang Department of Chemistry Zhejiang University (Campus Xixi) Hangzhou 310028 China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China

多代替的 3-pyrrolines 的 regio 选择、立体声选择的合成被开发了。多代替的 3-pyrrolines 被压克力与 azomethine ylides 吃了的甲基 2-(phenylselanyl ) 的 1,3-dipolar 出租机动三轮车增加在好收益综合，由 N-acylation 和 oxidatio... 详细信息

多代替的 3-pyrrolines 的 regio 选择、立体声选择的合成被开发了。多代替的 3-pyrrolines 被压克力与 azomethine ylides 吃了的甲基 2-(phenylselanyl ) 的 1,3-dipolar 出租机动三轮车增加在好收益综合，由 N-acylation 和 oxidation– 列在后面； phenylseleno 的消除组。

关键词：立体选择性合成多取代吡咯偶极环加成反应中国化学会丙烯酸酯 BV公司叶立德

Magnetized strange quark matter in the equivparticle model with both confinement and perturbative interactions

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Nuclear Science and Techniques 2016年第4期27卷 158-166页

作者： Cheng Peng Guang-Xiong Peng Cheng-Jun Xia jian-feng xu Shi-Peng Zhang School of Physics University of Chinese Academy of Sciences Theoretical Physics Center for Science Facilities Institute of High Energy Physics Synergetic Innovation Center for Quantum Effects and Application Hunan Normal University Key Laboratory of Frontiers in Theoretical Physics Institute of Theoretical Physics

We investigated the properties of strange quark matter in an external strong magnetic field with both confinement and leading-order perturbative interactions considered. It was found that the leading-order perturbative interaction can stiffen the equation of state of magnetized quark matter, while the magnetic field lowers the minimum energy per baryon. By solving the Tolman–Oppenheimer–Volkoff equations, we obtain the internal structure of strange stars. The maximum mass of strange stars can be as large as 2 times the solar mass.

关键词：奇异夸克物质微扰磁化 e模型状态方程能量最小奥本海默内部结构

Prostate volume does not provide additional predictive value to prostate health index for prostate cancer or clinically significant prostate cancer:results from a multicenter study in China

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Asian Journal of Andrology 2020年第5期22卷 539-543页

作者： Da Huang Yi-Shuo Wu Ding-Wei Ye Jun Qi Fang Liu Brian T Helfand Siqun L Zheng Qiang Ding Dan-feng xu Rong Na jian-feng xu Ying-Hao Sun Department of Urology Ruijin HospitalShanghai Jiao Tong University School of MedicineShanghai 200025China Department of Urology Huashan HospitalFudan UniversityShanghai 200040China Fudan Institute of Urology Huashan HospitalFudan UniversityShanghai 200040China Department of Urology Shanghai Cancer CenterFudan UniversityShanghai 200032China Department of Urology Xinhua HospitalShanghai Jiao Tong University School of MedicineShanghai 200092China Division of Urology NorthShore University Health SystemEvanstonIL 60201USA Program for Personalized Cancer Care NorthShore University Health SystemEvanstonIL 60201US A Departm ent of Urology Shanghai Changhai HospitalThe Second Military Medical UniversityShanghai 2CXD433China.

To evaluate whether prostate volume(PV)would provide additional predictive utility to the prostate health index(phi)for predicting prostate cancer(PCa)or clinically significant prostate cancer,we designed a prospective,observational multicenter study in two prostate biopsy cohorts.Cohort 1 included 595 patients from three medical centers from 2012 to 2013,and Cohort 2 included 1025 patients from four medical centers from 2013 to 2014.Area under the receiver operating characteristic curves(AUC)and logistic regression models were used to evaluate the predictive performance of PV-based derivatives and models.Linear regression analysis showed that both total prostate-specific antigen(tPSA)and free PSA(fPSA)were significantly correlated with PV(all P0.05).In conclusion,PV-based derivatives(both PHIV and PHID)and models incorporating PV did not improve the predictive abilities of phi for either PCa or clinically significant PCa.

关键词： China prostate cancer prostate health index prostate volume