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STUDY OF HOT cORROSION RESISTANcE MEcHANISMS OF ARc SPRAYING cOATINGS

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Acta Metallurgica Sinica(English Letters) 1999年第5期12卷 1007-1013页

作者： S.N .Ma, q.Liu and c.q. Li Surface Engineering Research Institute of cMES, Beijing 1.0072, china

According to the working condition of boiler tubes of power station, hot corrosion tests were carried out at two temperatures (650℃ and 800℃) to simulate the environment of coal fired boiler. The hot corrosion resistance and mechanism of three arc spraying coatings (SL30, 45cT and FecrAl) have been studied. The result showed that coating SL30 and 45cT have a better protection ability against hot corrosion. It indicated that a protective cr 2O 3 scale formed on the surface of coating SL30 and coating 45cT.

关键词： arc spraying coating hot corrosion

The eastward subtropical countercurrent on isopycnal surface in the western North Pacific

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Science china Earth Sciences 2005年第7期48卷 1065-1073页

作者： LI Rongfeng1. YOU Xiaobao1.& Peter c. chu2 1. LASG, Institute of Atmospheric Physics, chinese Academy of Sciences, Beijing 1.0029, china 2. Department of Oceanography, Naval Postgraduate School, Monterey, cA 93943-51.2, USA LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Department of Oceanography Naval Postgraduate School Monterey CA 93943-5122 United States

The monthly circulations on isopycnal surface in the western North Pacific are calculated based on the Navy’s Generalized Digital Environmental Model climatological tem- perature and salinity data on a 1.2° × 1.2° grid using a P-vector method. The eastward Sub- tropical countercurrent (STcc) in the central subtropical gyre has been studied with emphasis on its spatial distribution, vertical structure, volume transport and its nearby eddy phenomenon. The results reproduce the observed feature of STcc, and reveal some new phenomena on isopycnal surface, such as: (1. At σθ = 24.6, there is strong seasonal variability in the distribution, origin and flow status of STcc. There is no STcc in January, February and March. (2) From May to October, a branch of the Kuroshio countercurrent to the south of Japan merges into STcc, which increases the velocity of STcc and widens its width. (3) The velocity vector field shows that STcc and nearby eddies coexist. (4) The eastward volume transport of STcc across 1.7.5°E is the strongest in summer with the maximum of 6.9 Sv ( 1.Sv ≡ 1.6 m3 s?1. in August, and weaker in spring and autumn with 1.7 Sv in April and 1.6 Sv in November. Most of the transports of STcc occur between isopycnal surfaces 24.0σθ and 25.0σθ. (5) The distributions of the zonal flow along 1.7.5°E show that the flow core of STcc is between 24.3σθ and 24.7σθ .

关键词： P-vector method on isopycnal surface eastward subtropical countercurrent eddy phenomenon.

Black hole shadows in Einstein-Bel-Robinson gravity

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chinese Physics c 2024年第5期48卷 272-283页

作者： B.Hamil B.c.Lütfüoğlu Laboratoire de Physique Mathématique et Subatomique Facultédes Sciences ExactesUniversitéConstantine 1ConstantineAlgeria Department of Physics University of Hradec KrálovéRokitanského 6250003 Hradec KrálovéCzechia

Gravity models given by higher-order scalar curvature corrections are believed to bear important consequences. Einstein-Bel-Robinson (EBR) gravity with quartic curvature modification motivated Sajadi et al. to explore static spherically symmetric black hole solutions using perturbative methods. In this study, inspired by their work, we investigate AdS black hole shadows in EBR gravity and demonstrate how the gravity parameter alters the energy emission rate. Finally, we address the same problem in the presence of plasma, because the black holes are thought to be surrounded by a medium that changes the geodesic of photons.

关键词： black hole shadows Einstein-Bel-Robinson gravity plasma

A simple criterion for finite time stability with application to impacted buckling of elastic columns

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Applied Mathematics and Mechanics(English Edition) 2018年第3期39卷 305-316页

作者： c.q.RU Department of Mechanical Engineering University of Alberta

The existing theories of finite-time stability depend on a prescribed bound on initial disturbances and a prescribed threshold for allowable responses. It remains a challenge to identify the critical value of loading parameter for finite time instability observed in experiments without the need of specifying any prescribed threshold for al- lowable responses. Based on an energy balance analysis of a simple dynamic system, this paper proposes a general criterion for finite time stability which indicates that finite time stability of a linear dynamic system with constant coefficients during a given time interval [0, tf] is guaranteed provided the product of its maximum growth rate （determined by the maximum eigen-root pl 〉0） and the duration tf does not exceed 2, i.e., pltf 〈2. The proposed criterion （pltf=2） is applied to several problems of impacted buckling of elastic columns：（i） an elastic column impacted by a striking mass, （ii） longitudinal impact of an elastic column on a rigid wall, and （iii） an elastic column compressed at a constant speed （＂Hoff problem＂）, in which the time-varying axial force is replaced approximately by its average value over the time duration. comparison of critical parameters predicted by the proposed criterion with available experimental and simulation data shows that the proposed criterion is in robust reasonable agreement with the known data, which suggests that the proposed simple criterion （pltf---2） can be used to estimate critical parameters for finite time stability of dynamic systems governed by linear equations with constant coefficients.

关键词： finite time stability, buckling impact, elastic column, Hoff problem, dy-namic buckling, stability criterion

Formation and migration of space charge packet in low density polyethylene

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Science china(Technological Sciences) 2005年第3期48卷 354-360页

作者： ZHENG Feihu 1., ZHANG Yewen 1., GONG Bin 1., ZHU Jianwei 1.& WU changshun 2 1. Pohl Institute of Solid State Physics, Tongji University, Shanghai 200092, china 2. china National center for quality Supervision and Test of Electric Ware and cable, Shanghai 200093, china Pohl Institute of Solid State Physics Tongji University Shanghai China china National center for quality Supervision and Test of Electric Ware and cable Shanghai China

Pressure wave propagation (PWP) method was utilized to observe the space charges packet-like behavior in sheet samples of low-density polyethylene (LDPE) under the relative low electric field. The experimental results show that space charge packets are always generated at the anode and move across the sample to the cathode regardless of the polarity of Dc voltage. This paper discusses the migration of space charge packets at 30–40°c, the possible charge resource of space charge packets carriers and trap level of the space charge.

关键词： solid dielectric,low-density polyethylene,space charge packet,trap.

Population-size-dependent branching processes in Markovian random environments

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chinese Science Bulletin 1998年第8期43卷 635-638页

作者： WANG Hanxing 1.and DAI Yonglong 2 1. Department of Mathematics, Shanghai University, Shanghai 201.00, china 2. Department of Mathematics, Zhongshan University, Guangzhou 51.275, china Department of Mathematics Shanghai University Shanghai China Department of Mathematics Zhongshan University Gunngzhou China

A branching model {Z n} n≥0is considered where the offspring distribution of the population’s evolution is not only dependent on the population size, but also controlled by a Markovian environmental process {ξ n} n≥0. For this model, asymptotic behaviour is studied such as limn→∞Z n and limn→∞Z n/m n in the case that the mean m k, θof the offspring distribution converges to m>1.as the population size k grows to ∞. In the case that {ξ n} n≥0is an irreducible positive recurrent Markov chain, certain extinction (i.e. P(Z n=0 for some n)=1. and noncertain extinction (i.e. P(Z n=0 for some n)1. are studied.

关键词： Markov chains in random environments stochastic population models branching processes.

A novel non-invasive model to predict high-risk varices in cirrhotic patients

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Hepatobiliary Surgery and Nutrition 2024年第3期13卷 530-532页

作者： Kelvin K.c.Ng Department of Surgery The Chinese University of Hong Kong Medical CentreHong KongChina

Acute variceal bleeding is one of the most common and potentially life-threatening complications in patients with liver *** is conventionally diagnosed by oesophagogastroduodenoscopy,which is invasive to patients and carries hospital *** would be more cost-effective if non-invasive tests could screen out high-risk patients who developed acute variceal bleeding requiring endoscopic *** can potentially reduce the need for invasive procedures for cirrhotic *** recent years,there have been advancements in non-invasive methods for assessing the risk of variceal *** include transient elastography(FibroScan)of the liver and spleen,platelet count,imaging modalities[ultrasound or magnetic resonance imaging(MRI)],and non-invasive liver function tests[child-Pugh score or the Model for End-Stage Liver Disease(MELD)score].The 201. Baveno VI consensus is developed by an international panel of experts to improve the diagnosis and management of portal hypertension and its complications,specifically focusing on variceal bleeding in patients with cirrhosis(1..The consensus emphasizes using noninvasive methods to screen out high-risk varices(HRV)requiring therapeutic *** key features of the Baveno VI criteria include a liver stiffness measurement(LSM)count>1.0,000/*** can confidently rule out *** has been proven to avoid unnecessary endoscopy up to 40%with a specificity of up to 46%(2).In recent years,spleen stiffness measurement(SSM)has been a useful tool to assess portal hypertension and to predict ***,the revised Baveno VII consensus in 2022 recommends SSM≤40 kPa would avoid more unnecessary endoscopy in patients who fall outside Baveno VI criteria,with a missed HRV rate of<5%(3).

关键词： Non-invasive model high-risk varices cirrhosis

Liver transplantation as an alternative for the treatment of neuroendocrine liver metastasis: Appraisal of the current evidence

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Hepatobiliary & Pancreatic Diseases International 2024年第2期23卷 146-153页

作者： Philip c.Muller Matthias Pfister Dilmurodjon Eshmuminov Kuno Lehmann Department of Surgery and Transplantation University Hospital ZurichRämistrasse 100Zurich CH-8091Switzerland

Background:Liver transplantation(LT)for neuroendocrine liver metastases(NELM)is still in *** comparing LT with liver resection(LR)for NELM are scarce,as patient selection is heterogeneous and experience is *** goal of this review was to provide a critical analysis of the evidence on LT versus LR in the treatment of *** sources:A scoping literature search on LT and LR for NELM was performed with PubMed,including English articles up to March ***:International guidelines recommend LR for NELM in resectable,well-differentiated tumors in the absence of extrahepatic metastatic disease with superior results of LR compared to systemic or liver-directed *** liver surgery has extended resectability criteria whilst entailing increased perioperative risk and short disease-free *** highly selected patients(based on the Milan criteria)with unresectable NELM,oncologic results of LT are *** factors include tumor biology(G1.G2)and burden,waiting time for LT,patient age and extrahepatic *** on low-level evi-dence,LT for low-grade NELM within the Milan criteria resulted in improved disease-free survival and overall survival compared to *** benefits of LT were lost in patients beyond the Milan ***:With adherence to strict selection criteria especially tumor biology,LT for NELM is becoming a valuable option providing oncologic benefits compared to *** evidence suggests even stricter selection criteria with regard to tumor biology.

关键词： Liver transplantation Neuroendocrine liver metastases Liver resection Selection criteria Tumor biology

Kinetics and reaction mechanism of phenol hydroxylation catalyzed by La-cu_4FeAlcO_3

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Science china chemistry 2005年第6期48卷 530-537页

作者： cHEN chunxia1.2, XU chenghua1. FENG Liangrong1. SUO Jishuan1.& qIU Fali1.1. chengdu Institute of Organic chemistry, chinese Academy of Sciences, chengdu 61.041. china 2. Graduate School of the chinese Academy of Sciences, Beijing 1.0039, china chengdu Institute of Organic chemistry Chinese Academy of Sciences Chengdu China Graduate School of the chinese Academy of Sciences Beijing China

The present work synthesizes La-cu4FeAlcO3 catalyst under microwave irradiation and characterizes its structure using XRD and IR techniques. The results show that the obtained La-cu4FeAlcO3 has a hydrotalcite structure. In the phenol hydroxylation with H2O2 catalyzed by La-cu4FeAlcO3, the effects of reaction time and phenol/H2O2 molar ratio on the phenol hy-droxylation, and relationships between the initial hydroxylation rate with concentration of the catalyst, phenol, H2O2 and reaction temperature are also investigated in details. It is shown the phenol conversion can reach 50.09% (mol percent) in the phenol hydroxylation catalyzed by La-cu4FeAlcO3, under the reaction conditions of the molar ratio of phenol/H2O2 1.2, the amount ratio of phenol/catalyst 20, reaction temperature 343 K, reaction time 1.0 min, 1. mL distilled water as solvent. Moreover, a kinetic equation of v = k[La ? cu 4 FeAlcO 3 ][c 6 H 5 OH][H 2 O 2]. and the activation energy of Ea=58.37 kJ/mol are obtained according to the kinetic studies. Due to the fact that the HO-cu+-OH species are detected in La-cu4FeAlcO3/H2O2 system by XPS, the new mechanism about the generation of hydroxyl free radicals in the phenol hydroxylation is pro-posed, which is supposed that HO-cu+-OH species are transition state in this reaction.

关键词： rare earth, hydrotalcite, microwave irradiation, phenol hydroxylation, kinetics, reaction mechanism.