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Experimental Investigation of Vibration Response of A Free-Hanging Flexible Riser Induced by Internal Gas-Liquid Slug Flow

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China Ocean Engineering 2018年第6期32卷 633-645页

作者： ZHU hong-jun ZHAO hong-lei GAO Yue State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University

The vibration response of a free-hanging flexible riser induced by internal gas-liquid slug flow was studied experimentally in a small-diameter tube model based on Froude number criterion. The flow regime in a curved riser model and the response displacements of the riser were simultaneously recorded by high speed cameras. The gas superficial velocity ranges from 0.1 m/s to 0.6 m/s while the liquid superficial velocity from 0.06 m/s to 0.3 m/*** slugging type 3, unstable oscillation flow and relatively stable slug flow were observed in the considered flow rates. Severe slugging type 3 characterized by premature gas penetration occurs at relatively low flow rates. Both the cycle time and slug length become shorter as the gas flow rate increases. The pressure at the riser base undergoes a longer period and larger amplitude of fluctuation as compared with the other two flow regimes. Additionally, severe slugging leads to the most vigorous in-plane vibration. However, the responses in the vertical and horizontal directions are not synchronized. The vertical vibration is dominated by the second mode while the horizontal vibration is dominated by the first mode. Similar to the vortex-induced vibration, three branches are identified as initial branch, build-up branch and descending branch for the response versus the mixture velocity of gas-liquid flow.

关键词： gas-liquid two-phase flow severe slugging liquid slug flexible riser flow-induced vibration

维普期刊数据库

Abrasive-free polishing of hard disk substrate with H_(2)O_(2)-C_(4)H_(10)O_(2)-Na_(2)S_(2)O_(5) slurry

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Friction 2013年第4期1卷 359-366页

作者： Weitao ZHANG hong lei Research Center of Nano-Science and Nano-Technology Shanghai UniversityShanghai 200444China

The effect of tert-butyl hydroperoxide-sodium pyrosulfite((CH3)3COOH-Na2S2O5)as an initiator system in H2O2-based slurry was investigated for the abrasive-free polishing(AFP)of a hard disk *** polishing results show that the H_(2)O_(2)-C_(4)H_(10)O_(2)-Na_(2)S_(2)O_(5) slurry exhibits a material removal rate(MRR)that is nearly 5 times higher than that of the H2O2 slurry in the AFP of the hard disk *** addition,the surface polished by the slurry containing the initiator exhibits a lower surface roughness and has fewer nano-asperity peaks than that of the H2O2 ***,we investigate the polishing mechanism of H_(2)O_(2)-C_(4)H_(10)O_(2)-Na_(2)S_(2)O_(5) *** spin-resonance spectroscopy and auger electron spectrometer analyses show that the oxidizing ability of the H_(2)O_(2)-C_(4)H_(10)O_(2)-Na_(2)S_(2)O_(5) slurry is much greater than that of the H2O2 *** results of potentiodynamic polarization measurements show that the hard disk substrate in the H_(2)O_(2)-C_(4)H_(10)O_(2)-Na_(2)S_(2)O_(5) slurry can be rapidly etched,and electrochemical impedance spectroscopy analysis indicates that the oxide film of the hard disk substrate formed in the H_(2)O_(2)-C_(4)H_(10)O_(2)-Na_(2)S_(2)O_(5) slurry may be loose,and can be removed easily during *** better oxidizing and etching ability of H_(2)O_(2)-C_(4)H_(10)O_(2)-Na_(2)S_(2)O_(5) slurry leads to a higher MRR in AFP for hard disk substrates.

关键词： abrasive-free polishing material removal rate initiator hard disk substrate

A GENERALIZED QUASI-NEWTON EQUATION AND COMPUTATIONAL EXPERIENCE

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Journal of Computational Mathematics 2006年第5期24卷 665-674页

作者： lei-hong Zhang Ping-qi Pan Department of Mathematics Southeast University Nanjing 210096 China

The quasi-Newton equation has played a central role in the quasi-Newton methods for solving systems of nonlinear equations and/or unconstrained optimization problems. Insteady Pan suggested a new equation, and showed that it is of the second order while the traditional of the first order, in certain approximation sense [12]. In this paper, we make a generalization of the two equations to include them as special cases. The generalized equation is analyzed, and new updates are derived from it. A DFP-like new update outperformed the traditional DFP update in computational experiments on a set of standard test problems.

关键词： System of nonlinear equations, Unconstrained optimization, Quasi-Newtone quation Second-order Quasi-Newton equation, Update formula.

Orientational Isomerism and Its Reactivity of a Main Group Sandwich Anion[Ge_(9)-In-Ge_(9)]^(5-)

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Chinese Journal of Chemistry 2023年第19期41卷 2432-2438页

作者： hong-lei Xu lei Qiao Zhong Ming Sun State Key Laboratory of Elemento-Organic Chemistry Tianjin Key Lab of Rare Earth Materials and ApplicationsSchool of Material Science and EngineeringNankai UniversityTianjin 300350China

Two isomers of a sandwich-type anion [Ge_(9)-In-Ge_(9)]^(5–) were synthesized by controlling the chelating agents (2,2,2-crypt/18-C-6). Further reactions with early/late transition metal complexes, Mo(CO)_(6) and Ni(COD)_(2), respectively, yielded two new types of inorganic sandwich derivatives: a half-sandwich cluster [Ge_(9)-In-Mo(CO)_(5)]^(3–) with a low-valence In(I) center and an unsymmetrical sandwich-type cluster {[(Ni@Ge_(9))In(Ni_(0.648)@Ge_(9))]}^(5–) due to the insertion of Ni atoms, respectively. The isolation of these new derivatives demonstrates the reactivity of sandwich-type [Ge_(9)-In-Ge_(9)]^(5–) acting as the precursor, which provides some enlightenment for constructing new inorganic sandwich compounds.

关键词： Sandwich complex Cluster compounds Main group elements Germanium Indium

不同禾本科植物对矿区重金属污染土壤的修复效果研究

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陕西科技大学学报 2025年第1期43卷 23-28页

作者：贾红磊安昊东王晴李成涛陕西科技大学环境科学与工程学院陕西西安710021

以秦岭腹地凤县典型铅锌尾矿区周边的农田土壤为研究对象,采用黑麦草、剪股颖、百慕大草三种类型的草本植物进行室内盆栽实验,阐述了干旱胁迫对植物生长的影响,探究不同禾本科植物在干旱半干旱地区对重金属污染土壤的修复效果,以期筛选... 详细信息

以秦岭腹地凤县典型铅锌尾矿区周边的农田土壤为研究对象,采用黑麦草、剪股颖、百慕大草三种类型的草本植物进行室内盆栽实验,阐述了干旱胁迫对植物生长的影响,探究不同禾本科植物在干旱半干旱地区对重金属污染土壤的修复效果,以期筛选出能够适合在金属矿区修复中种植的耐旱性草本植物.结果表明:相比剪股颖和百慕大草,黑麦草在该土壤条件下能够具有较高的生物量累积,且在干旱条件下生物量降低的较少(P<0.05),黑麦草的丙二醛(MDA)含量与电导率(EC)较低,说明其具有较好的耐旱能力和较高的重金属耐受能力(P<0.05).在重金属污染土壤修复中,黑麦草中Cd、Pb和Zn的含量最高,且对Cd的富集系数可达到0.98,种植黑麦草对土壤中Cd的去除效率高达50%以上,Pb的去除效率为15.5%.因此,研究认为黑麦草对于凤县矿区Pb、Zn和Cd污染土壤具有更好的修复潜力.

关键词：重金属干旱土壤修复植物筛选

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Review on synergistic damage effect of irradiation and corrosion on reactor structural alloys

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Nuclear Science and Techniques 2024年第3期35卷 109-141页

作者： Hui Liu Guan-hong lei He-Fei Huang Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

The synergistic damage effect of irradiation and corrosion of reactor structural materials has been a prominent research *** paper provides a comprehensive review of the synergistic effects on the third-and fourth-generation fission nuclear energy structural materials used in pressurized water reactors and molten salt *** competitive mechanisms of multiple influencing factors,such as the irradiation dose,corrosion type,and environmental temperature,are summarized in this *** approaches are proposed to alleviate the synergistic damage caused by irradiation and corrosion,thereby promoting in-depth research in the future and solving this key challenge for the structural materials used in reactors.

关键词： Irradiation and corrosion Synergistic effect Austenitic stainless steels Nickel-based alloys Reactors

维普期刊数据库

Experimental investigation of the effect of the wall proximity on the mode transition of a vortex-induced vibrating flexible pipe and the evolution of wall-impact

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Journal of Hydrodynamics 2022年第2期34卷 329-353页

作者： hong-jun Zhu hong-lei Zhao Yi-pu Xie Xu Zhang State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500China

The present work experimentally investigates the vortex-induced vibration(VIV)and the pipe-wall impact of a flexible pipe in an oblique *** flexible pipe with an aspect ratio of 86.67 and an oblique angle of 30°is immersed in the water flow with the initial gap ratio in the range of 0.2–0.8 and *** space-time varying oscillation responses in both the in-line and cross-flow directions are recorded using the non-intrusive optical measurement with high-speed cameras in the normal reduced velocity range of 3.40–*** oblique flow induces the spatial variations of the inclination angle to the flexible pipe as a result of the bending deformation during the ***,the flexible pipe experiences an asymmetrical response along the span and an out-of-sync mode transition in the in-line and cross-flow *** the gap ratio decreases,the VIV response is suppressed,and the vibration regions of lower modes are prolonged with the result of the delay of higher excited ***,the wall proximity results in an upward deflection of the equilibrium position,and this offset is enlarged with the decrease of the gap *** occurrence of the pipe-wall impact depends on the amplitude of the spatial-temporal varying oscillation and the dominant response *** pipe-wall impact patterns are proposed in terms of the number and the length of the contact pipe *** evolution of the pipe-wall impact pattern with the increase of the normal reduced velocity is closely related to the variations of the dominant response mode and the amplitude and the alteration of its spatial distribution.

关键词： Wall proximity oblique flow wall impact mode transition vortex-induced vibration(VIV)

Preparation of Ag2O modified silica abrasives and their chemical mechanical polishing performances on sapphire

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Friction 2017年第4期5卷 429-436页

作者： Baichun ZHANG hong lei Yi CHEN Research Center of Nano-Science and Nano-Technology Shanghai UniversityShanghai 200444China

The chemical mechanical polishing (CMP) process has become a widely accepted global planarization *** abrasive material is one of the key elements in *** the presented paper,an Ag-doped colloidal SiO2 abrasive is synthesized by a seed-induced growth *** is characterized by time-of-flight secondary ion mass spectroscopy and scanning electron microscopy to analyze the composition and *** CMP performance of the Ag-doped colloidal silica abrasives on sapphire substrates is *** results show the material removal rate (MRR) of Ag-doped colloidal silica abrasives is obviously higher than that of pure colloidal silica abrasives under the same testing *** surfaces that are polished by composite colloidal abrasives exhibit lower surface roughness (Ra) than those polished by pure colloidal silica ***,the acting mechanism of Ag-doped colloidal SiO2 composite abrasives in sapphire CMP is analyzed by X-ray photoelectron spectroscopy,and analytical results show that element Ag forms Ag2O which acts as a catalyst to promote the chemical effect in CMP and leads to the increasing of MRR.

关键词： chemical mechanical polishing Ag-doped colloidal silica abrasive sapphire material removal rate

ON AN EFFICIENT IMPLEMENTATION OF THE FACE ALGORITHM FOR LINEAR PROGRAMMING＊

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Journal of Computational Mathematics 2013年第4期31卷 335-354页

作者： lei-hong Zhang Wei hong Yang Li-Zhi Liao Department of Applied Mathematics Shanghai University of Finance and Economics Shanghai 200433 China School of Mathematical Sciences Fudan University Shanghai 200433 China Department of Mathematics and Institute of Computational and Theoretical Studies Hong Kong Baptist University Hong Kong China

In this paper, we consider the solution of the standard linear programming [Lt＇）. A remarkable result in LP claims that all optimal solutions form an optimal face of the underlying polyhedron. In practice, many real-world problems have infinitely many optimal solutions and pursuing the optimal face, not just an optimal vertex, is quite desirable. The face algorithm proposed by Pan [19] targets at the optimal face by iterating from face to face, along an orthogonal projection of the negative objective gradient onto a relevant null space. The algorithm exhibits a favorable numerical performance by comparing the simplex method. In this paper, we further investigate the face algorithm by proposing an improved implementation. In exact arithmetic computation, the new algorithm generates the same sequence as Pan＇s face algorithm, but uses less computational costs per iteration, and enjoys favorable properties for sparse problems.

关键词： Linear programming Level face Optimal face Rank-one correction.