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Shift current response in elemental two-dimensional ferroelectrics

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npj Computational Materials 2023年第1期9卷 1675-1685页

作者： Zhuang qian jian Zhou Hua Wang Shi Liu Zhejiang University HangzhouZhejiang 310058China Key Laboratory for Quantum Materials of Zhejiang Province Department of PhysicsSchool of Science and Research Center for Industries of the FutureHangzhouZhejiang 310030China Center for Alloy Innovation and Design State Key Laboratory for Mechanical Behavior of MaterialsXi’an Jiaotong UniversityXi’an 710049China Institute of Natural Sciences Westlake Institute for Advanced StudyHangzhouZhejiang 310024China

A bulk material without inversion symmetry can generate a direct current under *** interface-free current generation mechanism,referred to as the bulk photovoltaic effect(BPVE),does not rely on p-n ***,we explore the shift current generation,a major mechanism responsible for the BPVE,in single-element two-dimensional(2D)ferroelectrics represented by phosphorene-like monolayers of As,Sb,and *** strong covalency,small band gap,and large joint density of states afforded by these elemental 2D materials give rise to large shift currents,outperforming many state-of-the-art *** find that the shift current,due to its topological nature,depends sensitively on the details of the Bloch wave *** is crucial to consider the electronic exchange-correlation potential beyond the generalized gradient approximation as well as the spin-orbit interaction in density functional theory calculations to obtain reliable frequency-dependent shift current responses.

关键词： functions materials details

Wiener model identification and nonlinear model predictive control of a pH neutralization process based on Laguerre filters and least squares support vector machines

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第1期12卷 25-35页

作者： qing-chao WANG jian-zhong ZHANG School of Energy Science and Engineering Harbin Institute of Technology Harbin 150001 China SINOPEC Safety Engineering Institute Qingdao 266071 China

This paper deals with Wiener model based predictive control of a pH neutralization *** dynamic linear block of the Wiener model is parameterized using Laguerre filters while the nonlinear block is constructed using least squares support vector machines (LSSVM).Input-output data from the first principle model of the pH neutralization process are used for the Wiener model *** results show that the proposed Wiener model has higher prediction accuracy than Laguerre-support vector regression (SVR) Wiener models,Laguerre-polynomial Wiener models,and linear Laguerre *** identified Wiener model is used here for nonlinear model predictive control (NMPC) of the pH neutralization *** set-point tracking performance of the proposed NMPC is compared with those of the Laguerre-SVR Wiener model based NMPC,Laguerre-polynomial Wiener model based NMPC,and linear model predictive control (LMPC).Validation results show that the proposed NMPC outperforms the other three controllers.

关键词： Wiener model Nonlinear model predictive control (NMPC) pH neutralization process Laguerre filters Least squares support vector machines (LSSVM)

Influence of reaction piles on test pile response in a static load test

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第3期14卷 198-205页

作者： qian-qing ZHANG Shu-cai LI Zhong-miao ZHANG Geotechnical and Structural Engineering Research Center Shandong University MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Zhejiang University

This work presents a new analytical method to analyze the influence of reaction piles on the test pile response in a static load *** our method,the interactive effect between soil and pile is simulated using independent springs and the shear displacement method is adopted to analyze the influence of reaction piles on test pile ***,the influence of the sheltering effect between reaction piles and test pile on the test pile response is taken into *** cases are analyzed to verify the rationality and efficiency of the present *** method can be easily extended to a nonlinear response of an influenced test pile embedded in a multilayered soil,and the validity is also demonstrated using centrifuge model tests and a computer program presented in the *** present analyses indicate that the proposed method will lead to an underestimation of the test pile settlement in a static load test if the influence of the presence of reaction piles on the test pile response is neglected.

关键词： Test pile Reaction pile Shear displacement method Sheltering effect Multilayered soil

Dexmedetomidine as an adjunct to peripheral nerve blocks in pediatric patients

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World Journal of Pediatrics 2022年第4期18卷 251-262页

作者： Jing Yang Yu Cui Rong Cao qing-Hua Huang qian-qian Zhang Department of Anesthesiology The Affiliated HospitalSchool of MedicineUESTC Chengdu Women’s&Children’s Central HospitalNo.1617Riyue AvenueQingyang DistrictChengdu 610091China

Background Combining local anesthetics with dexmedetomidine(DEX)for nerve blocks has been tested and confirmed as an alternative technique to strengthen analgesia in adults,but the evidence supported this proposal in pediatrics was not convincing ***,we intend to conduct a meta-analysis to make an appraisal of the effects of DEX as a local anesthetic adjuvant on peripheral nerve blocks in *** The analysis has been registered on https://***/prospero/with the registration number CRD42021254029 on June 10th,***,Ovid MEDLINE,Embase and Cochrane central register were searched for the randomized controlled trials(RCTs)that are relevant to child/pain/DEX or block up to April 30,*** Eight RCTs were included for data *** pooled results showed a significantly reduced number of patients who required postoperative analgesics within DEX groups[odds ratio=0.1,95%confidence interval(CI)0.03-0.32,P<0.001].And DEX significantly prolonged the duration of analgesia of local anesthetics in the meantime[standardized mean difference(SMD)=4.93,95%CI 3.02-6.83,P<0.001].Nevertheless,adding DEX as an adjunct to local anesthetics would significantly decrease heart rate(SMD=-0.95,95%CI-1.45 to-0.45,P<0.001)and increase sedation score(SMD=1.6,95%CI 0.53-2.66,P=0.003)*** Adding DEX as an adjunct to peripheral nerve blocks can prolong analgesia until postoperative 8 hours in pediatric ***,the benefits should be weighed against the increasing risk of bradycardia and sedation in critical children.

关键词： Block Child Dexmedetomidine Pain

Isospin Effects of Critical Behavior in Lattice Gas Model

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Chinese Physics Letters 1999年第4期16卷 256-258页

作者： MA Yu-gang SU qian-min SHEN Wen-qing WANG jian-song CAI Xiang-zhou FANG De-qing Shanghai Institute of Nuclear Research Chinese Academy of SciencesShanghai 201800 Fudan-T.D.Lee Physics Laboratory Fudan UniversityShanghai 200433 CCAST(World Laboratory) P.O.Box 8730Beijing 100080

Isospin effects of the critical phenomena were studied via Xe isotopes in the frame of the lattice gas *** the critical temperatures for four Xe isotopes are close to 5.5 MeV at the same freeze-out density of about 0.39ρ*** critical values of power law parameter of mass distribution,mean multiplicity of intermediate mass fragments,information entropy and Campi's second moment show minor dependence on the isospin at the critical point.

关键词： point critical entropy

Distribution characteristics of inclusions along with the surface sliver defect on the exposed panel of automobile:A quantitative electrolysis method

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International Journal of Minerals,Metallurgy and Materials 2020年第11期27卷 1489-1498页

作者： Xiao-qian Pan jian Yang Joohyun Park Hideki Ono State Key Laboratory of Advanced Special Steel School of Materials Science and EngineeringShanghai UniversityShanghai 200444China Department of Materials Engineering Hanyang UniversityAnsan 426-791South Korea Faculty of Sustainable Design University of ToyamaToyama-ken 930-8555Japan

The specific distribution characteristics of inclusions along with the sliver defect were analyzed in detail to explain the formation mechanism of the sliver defect on the automobile exposed panel surface.A quantitative electrolysis method was used to compare and evaluate the three-dimensional morphology,size,composition,quantity,and distribution of inclusions in the defect and non-defect zone of automobile exposed *** Al2O3 inclusions were observed to be aggregated or chain-like shape along with the sliver defect of about 3–10μ*** aggregation sections of the Al2O3 inclusions are distributed discretely along the rolling direction,with a spacing of 3–7 mm,a length of 6–7 mm,and a width of about 3 *** inclusion area part is 0.04%–0.16%with an average value of 0.08%,the inclusion number density is 40 mm−2 and the inclusion average spacing is 25.13μ*** inclusion spacing is approximately 40–160μm,with an average value of 68.76μm in chain-like inclusion *** average area fraction and number density of inclusions in the non-defect region were reduced to about 0.002%and 1–2 mm^−2,respectively,with the inclusion spacing of 400μm and the size of Al2O3 being 1–3μm.

关键词： automobile exposed panel sliver defect quantitative electrolysis three-dimensional inclusions aggregated inclusions chain-like inclusions

Effect of MgO on structure and crystallization behavior of CaO–SiO_(2)–Al_(2)O_(3) inclusions in Si–Mn deoxidized steel

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Journal of Iron and Steel Research International 2024年第11期31卷 2774-2787页

作者： Qi Xu Yao-qing Meng jian-li Li The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan430081HubeiChina Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan430081HubeiChina

To avoid coarse crystallization of glassy inclusions in Si–Mn deoxidized steel during hot rolling, the effect of MgO on the structure and crystallization behavior of CaO–SiO_(2)–Al_(2)O_(3) inclusions was investigated. The results showed that the crystallization temperature of the oxide melts decreased with increasing MgO content from 0 to 15.7 wt.%, which suggested that the addition of MgO would increase the temperature range of the crystalline transition. The increase in MgO content could decrease the crystallization activation energy of inclusions. With the increase in MgO content, the relative fractions of O_(Si)^(0) and O_(Si)^(1) structure units increased, and those of structure units O_(Si)^(2), O_(Si)^(3), and O_(Si)^(4) decreased, increasing the depolymerization degree of the silicate structure. The crystallization ratio of glassy inclusions in the steel crucible increased from 19.7% to 98.3% with increasing MgO content from 0 to 15.7 wt.%. The addition of MgO improved the crystallization ability of inclusions, because MgO provides free oxygen O_(2−) to destroy the bridging oxygens and form non-bridging oxygens O^(−), which depolymerizes silicate network structure and simplifies the [SiO_(4)]-tetrahedral structure. In addition, MgO would promote the precipitation of the Mg-containing phases with a high melting point. When the MgO content was increased above 12.1 wt.%, MgO·Al_(2)O_(3) and 2MgO·SiO_(2) crystalline phases would precipitate from the inclusions.

关键词： Si-Mn deoxidized steel Glassy inclusion Structure Crystallization Plasticization

Experimental Study on Combustion Characteristics and NOX Emissions of Pulverized Anthracite Preheated by Circulating Fluidized Bed

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Journal of Thermal Science 2011年第4期20卷 355-361页

作者： WANG Jun ZHU jian-guo LU qing-gang Institute of Engineering Thermophysics Chinese Academy of Sciences 11 Beisihuanxi Road Haidian District Beijing 100190 China Graduated University of Chinese Academy of Sciences Shijingshan District Beijing 100049 China

A 30 kW bench-scale rig of pulverized anthracite combustion preheated by a circulating fluidized bed （CFB） was developed. The CFB riser has a diameter of 90 mm and a height of 1,500 mm. The down-fired combustion chamber （DFCC） has a diameter of 260 mm and a height of 3,000 mm. Combustion experiments were carded out using pulverized anthracite with 6.74% volatile content. This low volatile coal is difficult to ignite and burn out. Therefore, it requires longer burnout time and higher combustion temperature, which results in larger NOx emis- sions. In the current study, important factors that influence the combustion characteristics and NOx emissions were investigated such as excess air ratio, air ratio in the reducing zone, and fuel residence time in the reducing zone. Pulverized anthracite can be quickly preheated up to 800~C in CFB when the primary air is 24% of theo- retical air for combustion, and the temperature profile is uniform in DFCC. The combustion efficiency is 94.2%, which is competitive with other anthracite combustion technologies. When the excess air ratio ranges from 1.26 to 1.67, the coal-N conversion ratio is less than 32% and the NOx emission concentration is less than 371 mg/m^3 （@6% O2）. When the air ratio in the reducing zone is 0.12, the NOx concentration is 221 mg/m^3 （@6% O2）, and the coal-N conversion ratio is 21%, which is much lower than that of other boilers.

关键词： circulating fluidized bed preheat pulverized anthracite NOx

Plasticity Induced by Twin Lamellar Structure in Magnesium Alloy

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Journal of Materials Science & Technology 2013年第12期29卷 1123-1128页

作者： Xiyan Zhang Chao Lou jian Tu qing Liu School of Materials Science and Engineering Chongqing University

Effect of {10-12} twins on the mechanical properties of magnesium alloy has received considerable research interest. A hot-rolled AZ31 Mg alloy sheet was subjected to dynamic plastic deformation with the aim of introducing {10-12} twin lamellar structure. It has been found that higher strength and better ductility are obtained when tensile loading is perpendicular to the c axis of twin region of the twin lamellar structured sample, indicating that the plasticity improvement caused by twins depends on the special strain path. The fracture morphology of the twin lamellar structured sample shows a dimple fracture mode under tensile loading perpendicular to the c axis, while the cleavage fracture with river pattern has been observed in other fractured samples. Above experimental results indicate that the interaction of dislocations and twin lamellae may play an important role in improving mechanical properties of Mg alloy.

关键词： Magnesium alloy Twin lameilar structure Mechanical behavior Plasticity