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Specific heat in superconductors

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Chinese Physics B 2020年第1期29卷 24-39页

作者： hai-hu Wen School of Physics Nanjing UniversityNanjing 210093China

Specific heat is a powerful tool to investigate the physical properties of condensed *** state is achieved through the condensation of paired electrons,namely,the Cooper *** condensed Cooper pairs have lower entropy compared with that of electrons in normal metal,thus specific heat is very useful in detecting the low lying quasiparticle excitations of the superconducting condensate and the pairing symmetry of the superconducting *** this brief overview,we will give an introduction to the specific heat investigation of the physical properties of *** show the data obtained in cuprate and iron based superconductors to reveal the pairing symmetry of the order parameter.

关键词： specific heat gap symmetry low lying quasiparticle excitations cuprates iron based superconductors

Local Least Product Relative Error Estimation for Varying Coefficient Multiplicative Regression Model

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Acta Mathematicae Applicatae Sinica 2019年第2期35卷 274-286页

作者： Da-hai hu School of Management University of Science and Technology of China

In this article, we consider the varying coefficient multiplicative regression model, which is very useful to model the positive response. The criterion of least product relative error(LPRE) is extended to the varying coefficient multiplicative regression model by kernel smoothing techniques. Consistency and asymptotic normality of the proposed estimator are established. Some numerical simulations are carried out to assess the performance of the proposed estimator. As an illustration, the ethanol data is analyzed.

关键词： varying coefficient model multiplicative regression model relative error kernel smoothing

Comparative study of vortex dynamics in CaKFe_4As_4 and Ba_(0.6)K_(0.4)Fe_2As_2 single crystals

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Science Bulletin 2019年第2期64卷 81-90页

作者： Wang Cheng hai Lin Bing Shen hai-hu Wen Center for Superconducting Physics and Materials National Laboratory of Solid State Microstructures and Department of Physics National Center of Microstructures and Quantum Manipulation Nanjing University School of Physics Sun Yat-sen University

We investigate the vortex dynamics in two typical hole doped iron based superconductors CaKFe_4As_4(CaK1144) and Ba_(0.6)K_(0.4)Fe_2As_2(BaK122) with similar superconducting transition temperatures. It is found that the magnetization hysteresis loop exhibits a clear second peak effect in BaK122 in wide temperature region while it is absent in CaK1144. However, a second peak effect of critical current density versus temperature is observed in CaK1144, which is however absent in BaK122. The different behaviors of second peak effect in BaK122 and CaK1144 may suggest distinct origins of vortex pinning in different systems. Magnetization and its relaxation have also been measured by using dynamical and conventional relaxation methods for both systems. Analysis and comparison of the two distinct systems show that the vortex pinning is stronger and the critical current density is higher in BaK122 system. It is found that the Maley's method can be used and thus the activation energy can be determined in BaK122 by using the time dependent magnetization in wide temperature region, but this is not applicable in CaK1144 *** we present the different regimes with distinct vortex dynamics in the field-temperature diagram for the two systems.

关键词： CaKFe4As4 Ba0.6K0.4Fe2As2 Magnetization hysteresis loop Vortex pinning Second peak effect Vortex dynamics

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World Journal of Emergency Medicine 2022年第6期13卷 425-432页

作者： hai hu Ni Yao Xiao-qin Lai Emergency Management Office of West China Hospital Sichuan UniversityChengdu 610041China China International Emergency Medical Team Chengdu 610041China Sichuan University’s Emergency Medical Rescue Base Chengdu 610041China Department of Critical Care Medicine West China HospitalSichuan UniversityChengdu 610041China Day Surgery Center West China HospitalSichuan UniversityChengdu 610041China West China School of Nursing Sichuan UniversityChengdu 610041China

BACKGROUND:There is limited evidence for emergency physicians and emergency trauma surgeons regarding the determinants of early and rapid assessment of older adult in-hospital mortality due to *** study explored factors related to the early and rapid assessment of the mortality among older adult earthquake trauma patients(OAETPs)and created a screening ***:Data on 7,308 OAETPs from the West China Earthquake Patients Database were analyzed *** 35 variables that can be obtained rapidly on arrival at the hospital were *** absolute shrinkage and selection operator(LASSO)regression analysis was ***,the nomogram for assessing the mortality of OAETPs was ***:We identified 10 independent mortality-related factors that contributed to the in-hospital mortality of *** 10 factors included age(odds ratio[OR]=1.061,95%confidence interval[CI]:1.031-1.090),dementia(OR=5.146,95%CI:1.169-17.856),coronary heart disease(CHD;OR=23.441,95%CI:4.799-83.927),malignant tumor(OR=8.497,95%CI:3.583-17.967),deep vein thrombosis(DVT;OR=7.110,95%CI:1.369-27.168),chronic kidney disease(CKD;OR=11.783,95%CI:5.419-24.407),pulse rate(PR;OR=1.036,95%CI:1.022-1.048),mean artery pressure(MAP;OR=0.960,95%CI:0.945-0.975),Glasgow Coma Scale(GCS;OR=0.864,95%CI:0.760-0.972),and Triage Revised Trauma Score(T-RTS,OR=0.485,95%CI:0.351-0.696).CONCLUSION:The 10 mortality-related factors could be quickly obtained on hospital arrival and should be the focal point of future earthquake response strategies regarding hospitalized older adults with trauma.A nomogram was constructed based on the factors for screening OAETPs with a higher risk of in-hospital mortality.

关键词： Trauma Mortality Earthquakes Elderly patients

Comparison of different versions of the quick sequential organ failure assessment for predicting in-hospital mortality of sepsis patients:A retrospective observational study

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World Journal of Emergency Medicine 2022年第2期13卷 114-119页

作者： hai hu Jing-yuan Jiang Ni Yao Emergency Office of West China Hospital Sichuan UniversityChengdu 610041China China International Emergency Medical Team Chengdu 610041China Emergency Department West China HospitalSichuan UniversityChengdu 610041China West China School of Nursing Sichuan UniversityChengdu 610041China Department of Critical Care Medicine West China HospitalSichuan UniversityChengdu 610041China

BACKGROUND:The quick sequential organ failure assessment(qSOFA)is recommended to identify sepsis and predict sepsis ***,some studies have recently shown its poor performance in sepsis mortality *** enhance its effectiveness,researchers have developed various revised versions of the qSOFA by adding other parameters,such as the lactate-enhanced qSOFA(LqSOFA),the procalcitonin-enhanced qSOFA(PqSOFA),and the modified qSOFA(MqSOFA).This study aimed to compare the performance of these versions of the qSOFA in predicting sepsis mortality in the emergency department(ED).METHODS:This retrospective study analyzed data obtained from an electronic register system of adult patients with sepsis between January 1 and December 31,*** operating characteristic(ROC)curve analyses were performed to determine the area under the curve(AUC),with sensitivity,specificity,and positive and negative predictive values calculated for the various ***:Among the 936 enrolled cases,there were 835 survivors and 101 *** AUCs of the LqSOFA,MqSOFA,PqSOFA,and qSOFA were 0.740,0.731,0.712,and 0.705,*** sensitivity of the LqSOFA,MqSOFA,PqSOFA,and qSOFA were 64.36%,51.40%,71.29%,and 39.60%,*** specificity of the four scores were 70.78%,80.96%,61.68%,and 91.62%,*** LqSOFA and MqSOFA were superior to the qSOFA in predicting in-hospital ***:Among patients with sepsis in the ED,the performance of the PqSOFA was similar to that of the qSOFA and the values of the LqSOFA and MqSOFA in predicting in-hospital mortality were greater compared to *** the added parameter of the MqSOFA was more convenient compared to the LqSOFA,the MqSOFA could be used as a candidate for the revised qSOFA to increase the performance of the early prediction of sepsis mortality.

关键词： Quick sequential organ failure assessment In-hospital mortality Sepsis Lactate-enhanced qSOFA Modified qSOFA

Uncovering the Phase Transition of Berlinite (α-AlPO_(4)) under High Pressure:Insights from First-principles Calculations

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Journal of Wuhan University of Technology(Materials Science) 2021年第2期36卷 248-254页

作者： LI Neng hu hai GUO Fei TAO haizheng State Key Laboratory of Optical Fiber and Cable Manufacture Technology(Yangtze Optical Fiber and Cable Joint Stock Limited Company) Wuhan 430073China State Key Laboratory of Silicate Materials for Architectures Wuhan University of TechnologyWuhan 430070China

We investigated the mechanism of crystalline-to-amorphous phase transition(CAPT)for amorphous berlinite(a-AlPO_(4))under high pressure using ab initio constant-pressure *** results show that the pressure to the change in phase transition takes place at around 20 GPa,which is inconsistent with the previous results of around 15 *** confirm the feasibility of our model,the calculated X-ray powder diffraction for crystal berlinite is concordant with the standard PDF *** assessing a full spectrum of properties including atomic structure,bonding characteristics,electron density of states and real-space pair distribution function at each pressure,we reveal the details of phase ***,all the information from our present results elucidates that Al-O bonds play an irreplaceable role during the process of phase transition to uncover the structural and electronic properties of ***,our work substantiates that it is essential to utilize a wide range of changes in order to provide a comprehensive understanding on the nature of the CAPT in other inorganic oxides.

关键词： aluminophosphate atomic and electronic structures phase transition ab initio calculation

Superconductivity in nickel-based 112 systems

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The Innovation 2022年第1期3卷 108-121页

作者： Qiangqiang Gu hai-hu Wen National Laboratory of Solid State Microstructures and Department of Physics Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China

Superconductivity has been discovered recently in infinite-layer nickel-based 112 thin films R_(1-x)A_(x)NiO_(2)(R=La,Nd,Pr and A=Sr,Ca).They are isostructural to the infinite-layer cuprate(Ca,Sr)CuO_(2)and are supposed to have a formal Ni 3d9 valence,thus providing a new platform to study the unconventional pairing mechanismof high-temperature *** important discovery immediately triggers a huge amount of innovative scientific curiosity in the *** this paper,we try to give an overview of the recent research progress on the newly found superconducting nickelate systems,both from experimental and theoretical *** mainly focus on the electronic structures,magnetic excitations,phase diagrams and superconducting gaps,and finally make some open discussions for possible pairing symmetries in Ni-based 112 systems.

关键词： field nickel infinite

On Mutual Transform Between Number-Difference State and Phase State Corresponding to Operational Phase Operator

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Communications in Theoretical Physics 2005年第3X期44卷 537-540页

作者： FAN Hong-Yi hu hai-Peng Department of Material Science and Engineering University of Science and Technology of China Hefei 230026 China

In the mutual transform between the number-difference state and the phase state corresponding to the operational phase operator we find that there exists an end-point ambiguousness. This problem can be avoided by Ligh... 详细信息

关键词： operational phase operator phase state end-point ambiguousness

Robust superconductivity and transport properties in (Li_(1-x)Fe_x)OHFeSe single crystals

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Science China(Physics,Mechanics & Astronomy) 2016年第5期59卷 11-15页

作者： hai Lin Jie Xing Xi Yu Zhu huan Yang hai-hu Wen Center for Superconducting Physics and Materials National Laboratory of Solid State Microstructures and Department of PhysicsNational Collaborative Innovation Center of Advanced Microstructures Nanjing University

The recently discovered(Li_(1-x) Fe_x)OHFe Se superconductor with T c about 40 K provides a good platform for investigating the magnetization and electrical transport properties of Fe Se-based superconductors. By using a hydrothermal ion-exchange method,we have successfully grown crystals of(Li_(1-x) Fe_x)OHFe Se. X-ray diffraction on the sample shows the single crystalline Pb O-type structure with the c-axis preferential orientation. Magnetic susceptibility and resistive measurements show an onset superconducting transition at around T c=38.3 K. Using the magnetization hysteresis loops and Bean critical state model, a large critical current J s is observed in low temperature region. The critical current density is suppressed exponentially with increasing magnetic *** dependencies of resistivity under various currents and fields are measured, revealing a robust superconducting current density and bulk superconductivity.

关键词： iron chalcogenides critical currents magnetic properties transport properties