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Microscopic phase-field simulation of L1_2 and D0_(22) phases during the early precipitation process of Ni-Cr-Al alloys

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Journal of University of Science and Technology Beijing 2006年第5期13卷 429-434页

作者： zhong chu Zheng Chen Yongxin Wang Yanli Lu Yongsheng Li State Key Laboratory for Solidification Processing Northwestern Polytechnical University Xi＇an 710072 China

The influence of temperature on the precipitation mechanism and sequence of L 12 and D022 phases during the early precipitation process of a ***%Cr-14at%Al alloy was simulated based on the microscopic phase-field model. In the range from 873 to 1373 K, the precipitation mechanism transformed from spinodal decomposition to non-classic nucleation and growth; the incubation period prolonged gradually with increasing temperature. The volume fraction of L12 phases increased and that of D022 phases decreased. D022 phases disappeared at 1373 K, and finally single-phase L12 phases were formed.

关键词： Ni-Cr-AI alloys microscope phase-field model precipitation ordering parameter simulation

Microscopic Phase-field Simulation of Competition Mechanism Between Ll_2 and D0_(22) Structure in Ni-Cr-Al Alloy

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Journal of Materials Science & Technology 2006年第3期22卷 315-320页

作者： zhong chu Zheng CHEN Yongxin WANG Yanli LU Yongsheng LI State Key Lab of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 China

Simulations are performed on temporal evolution of atom morphology and ordering parameters of Ni-14.5 Cr-16.5 Al alloy during early precipitation process at different temperatures based on microscopic phase-field theory; the relationship between precipitation sequence and mechanism of L12 and D022 structure and precipitation temperature are illuminated. The nonstoichiometric ordered L12 phases appear first with congruent ordering＋spinodal decomposition mechanism which is then followed by precipitation of D022 phases at ordering domain boundaries of L12 phases by spinodal decomposition mechanism at 1073 K and 1223 K. The nonstoichiometric L12 phases transform to stoichiometric ordering phases gradually. The incubation period of L12 and D022 phases is shorter at 1073 K than that 1223 K, and growth speed is higher at 1073 K. At 1373 K, L12 and D022 phases appear simultaneously by non-classical nucleation and growth mechanism. After that the particles of D022 phases diminish and disappear gradually; L12 phases grow and single L12 phases are remained at last.

关键词： Ni-Cr-Al Microscopic phase-field model Precipitation Ordering parameter Simulation

Controlled synthesis of silver nanoplates and nanoparticles by reducing silver nitrate with hydroxylamine hydrochloride

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Rare Metals 2017年第10期36卷 799-805页

作者： Zhi-Peng Cheng Xiao-zhong chu Xiao-Qing Wu Ji-Ming Xu Hui zhong Jing-Zhou Yin Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials Huaiyin Normal University Huaian 223300 China

An easy and effective method of silver nanoplate synthesis technique was created by reducing silver nitrate （AgNO3） with hydroxylamine hydrochloride （NH2OH·HCl） at room temperature. Silver nanoplates of various shapes, including triangular, truncated triangular, hexagonal, and truncated hexagonal, exhibit an average width and thickness of approximately 1 μm and 50 nm, respectively. Silver nanoparticles were acquired by placing polyvinyl pyrrolidone （PVP） in the reaction solution. The produced silver nanoparticles are quasi-spherical in shape and - 100 nm in size. The catalytic activity in the thermal decomposition of ammonium perchlorate （AID） was distinguished by thermogravimetric （TG） analysis and differential scanning calorimetry （DSC）. The outcomes reveal that the addition of silver nanoplates and nanoparticles diminishes the low decomposition temperature of AP by 7 and 14 ℃ and leads to a drop in the high decomposition temperature of AP by 60 and 110 ℃ and a rise in the total DSC heat release by 0.86 and 1.05 kJ.g^-1, respectively.

关键词： Silver nanoparticle Silver nanoplates Formation mechanism Ammonium perchlorate

Effects of composite oxide scale on oxidation resistance of superalloy K273

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China Foundry 2012年第2期9卷 165-170页

作者： Wang Haitao Tan Jiwen chu zhong Yu Huashun School of Mechanical Engineering Qingdao Technological UniversityQingdao 266033China Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong UniversityJinan 250061China

A Si-containing K273 superalloy was made using intermediate frequency induction furnace in the study. In the testing of oxidation resistance, the oxidation process of the alloy specimens during the testing at 900℃ for 500 h was examined by oxidation weight gain method. The morphology and composition of the oxide scales were determined using scanning electron microscope （SEM） and X-ray diffraction （XRD）, respectively. The effects of the transferring of ions and electrons on the oxidation resistance were further analyzed microscopically by semiconductor oxide models. The results show that the composite oxide scales consist of Cr203, SiO2 and spinel- type oxide MCr204, with flat and compact structure, and fine grains in uniform distribution. All of these endow the superalloy K273 with strong oxidation resistance. The reason for the powerful oxidation resistance of the composite scale is that the formation process of P＋N type semiconductor oxide enables to consume most of the surplus negative and positive ions in the oxide scales, which makes the number of the mobile ions and electrons dropped enormously, and the transfer rate of them falls heavily. So the oxidation rate of the metal phase in the alloy matrix is reduced significantly.

关键词： superalloy silicon oxide scale oxidation resistance

Constitutive Model for F45V Microalloyed Forging Steel at High Temperature

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Journal of Iron and Steel Research International 2014年第4期21卷 464-468页

作者： Jin WANG Wen-long MA zhong chu Qi ZHANG Department of Mechanical Engineering Qingdao Technological University

Isothermal hot compression experiments of F45V, a microalloyed steel, were performed on a Gleeble-1500 thermo-mechanical simulator at temperatures of 950--1200 ;C and strain rate of 0.01--10 s -1. Based on the experi- mental flow stress curves, a constitutive model that was expressed by the hyperbolic laws in an Arrhenius-type equa- tion was established, and the material parameters of the model were expressed as 6th order polynomial form of strain. Standard statistical parameters such as correlation coefficient and average absolute relative error were em- ployed to quantify the predictability of the model. They were found to be 0. 995 and 4.34% respectively. The results show that the established constitutive mode[ can predict the magnitude and tendency of flow stress with the increase of deformation accurately, and can be used for the numerical simulation of hot forging process of the F45V steel.

关键词： F45V steel microalloyed forging steel flow stress Arrhenius equation constitutive model

Preparation and properties of CdS/Au composite nanorods and hollow Au tubes

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Chinese Science Bulletin 2010年第10期55卷 921-926页

作者： YANG ZhaoHui chu HaiBin JIN zhong ZHOU WeiWei LI Yan Beijing National Laboratory for Molecular Sciences Key Laboratory for the Physics and Chemistry of Nanodevices College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

1-dimensional (1D) metal-semiconductor nano-scale composite superstructures based on Au nanoparticles and CdS nanorods were *** outer surface of CdS nanorods was modified with mercapto-ethylamine (MEA) in *** the aid of MEA,dense and uniform Au nanoparticles were deposited onto the external wall of CdS nanorods through in situ chemical reduction of *** Au nanoparticles induced further electroless deposition and a continuous layer of Au was formed on CdS *** hollow Au tubes were obtained after the inner CdS cores were etched by ***-Vis,FL,XPS,EDX,TEM and SEM measurements were carried out to characterize the produced *** quenching of the defect emission of CdS in CdS-nanorod/Au-nanoparticle hybrid superstructures was detected,which was ascribed to the energy transfer from the exciton of CdS to surface plasma resonance level of Au.

关键词： CdS纳米棒金纳米粒子纳米复合材料硫化镉空心表面等离子体共振光电子能谱性能

Some Results for Formal Local Cohomology Modules

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Communications in Mathematical Research 2010年第3期26卷 230-238页

作者： chu LI-zhong Du Xian-kun Department of Mathematics Suzhou University Suzhou Jiangsu 215006

Let （R, m） be a commutative Noetherian local ring, I an ideal of R and M a finitely generated R-module. Let limnHm^i（M/I^nM）be the ith formal local cohomology module of M with respect to *** this paper, we discuss some properties of formal local cohomology modules limnHm^i（M/I^nM）,which are analogous to the finiteness and Artinianness of local cohomology modules of a finitely generated module.

关键词： local cohomology formal local cohomology coartinian module minimax module Artinian module

The Expression of Estrogen Receptor Subtypes in Prolactinomas and Their Relationship to Tumor Biological Behavior

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Biomedical and Environmental Sciences 2015年第11期28卷 820-822页

作者： LI chu zhong GUI Song Bai ZONG Xu Yi ZHANG Ya Zhuo Beijing Neurosurgical Institute Neurosurgical Department of Beijing Tiantan Hospital Beijing Institute for Brain Disorders Brain Tumor Center Capital Medical University

Dopamine agonists （DA） are a first-line therapy for prolactinomas （PA）. However, nearly 10% of prolactinomas do not respond to DA therapy. A considerable number of studies have shown that estrogen plays an important role in the development of prolactinomas. However, the expression of estrogen receptors （ER） in prolactinomas has not been fully explored. Accordingly, we examined the levels of ESR1 and its subtypes A5-DeI-ESR1 and ESR2 mRNA in prolactinomas. In the present study,

关键词： RNA ESR The Expression of Estrogen Receptor Subtypes in Prolactinomas and Their Relationship to Tumor Biological Behavior PRL Del

Clinical features,radiological profiles,pathological features and surgical outcomes of pituicytomas:a report of 11 cases and a pooled analysis of individual patient data

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Military Medical Research 2022年第3期9卷 277-285页

作者： Jian-Hua Cheng Ding Nie Bin Li Song-Bai Gui chu-zhong Li Ya-Zhuo Zhang Luigi Maria Cavallo Peng Zhao Neurosurgical Department Beijing Tiantan HospitalCapital Medical UniversityNo.119 South Fourth Ring West RoadFengtai DistrictBeijing 100070China Department of Cell and Biology Beijing Neurosurgical InstituteBeijing 100070China Division of Neurosurgery UniversitáDegli Studi di Napoli FedericoⅡ80142 NaplesItaly

Background:Pituicytoma is an extremely rare low-grade glial tumor that is closely related to the neurohypophysis *** studies of pituicytomas include only several *** better understand this disease,we reviewed a series of cases of *** diagnosis and treatment of pituicytoma must be further ***:Eleven patients with pituicytoma admitted to Beijing Tiantan Hospital from 2012 to 2019 were *** clinical features,including radiological and histological examination,surgical records and prognosis were ***-eight other previously published cases of pituicytoma also were used to analyze the predictive factors for the *** Cox regression model was used for univariate and multivariate ***:Our patients included 5 males(45.5%)and 6 females(54.5%),with a mean age of 49.3 *** tumor was located in the suprasellar region in 5 patients(45.5%),intrasellar region in 4 patients(36.4%),and intrasellarsuprasellar region in 2 patients(18.2%).All patients were misdiagnosed with other common tumors in the sellar region before the *** the operation,gross total resection(GTR)of the tumor was achieved in 6 patients(54.5%),and subtotal resection(STR)was achieved in 5 patients(45.5%).The mean progression-free survival(PFS)time was 29.82 *** progression after surgical resection occurred in 4 patients(36.4%).Among them,60.0%of the patients(cases 4,5,7)with STR experienced progression,while 16.7%of the patients(case 2)with GTR experienced *** with the 68 cases in the literature,GTR was an independent risk factor for PFS time(P<0.05).Conclusions:Pituicytomas are more common in middle-aged people and the sellar *** clinical manifestations of pituicytomas are different,but no diagnostic clinical features have been identified other than an abnormally abundant blood ***,GTR is the best approach for the treatment of *** patients and longer follow-up perio

关键词： Pituicytoma Endoscopic transsphenoidal surgery Craniotomy Posterior pituitary lobe tumor