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Unimodal Sequences of Gorenstein Ideals of Codimension 4

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Acta Mathematica Sinica,English Series 1998年第4期14卷 563-568页

作者： Hyoung j. Ko Department of Mathematics. Yonsei University 134 Shinchon-dong Seodaemun-gu. Seoul Korea 120-749

We present Gorenstein ideals of condimension 4 which have unimodal Hilbert functions.

关键词： k-configuration Hilbert function Minimal free resolution Gorenstein ideal of codimension 4

The role of the Mg_(17)Al_(12)-phase in the high-pressure die-cast magnesium-aluminum alloy system

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journal of Magnesium and Alloys 2023年第11期11卷 4235-4246页

作者： j.P.Weiler Meridian Lightweight Technologies Canada

The Mg_(17)Al_(12)β-phase is highly influential to the performance of magnesium-aluminum high-pressure die-casting alloys. Numerous studies have investigated the effect of this phase on the room temperature and elevated-temperature mechanical properties as well as the corrosion,flammability, thermal conductivity and castability performance. This work summarizes the results of these works, as well as the studies that describe control of the Mg_(17)Al_(12)-phase through alloying additions that modify the microstructure and resulting alloy performance. The results of this work can be used as a basis for the development of alloying additions that enable modifications to the performance of high-pressure die-cast magnesium-aluminum-based alloys.

关键词： Magnesium alloys HPDC Alloy development Properties

Methylation status of p16 gene in colorectal carcinoma and normal colonic mucosa

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World journal of Gastroenterology 1999年第5期5卷 451-454页

作者： Zhang j Lai MD Chen j Hangzhou Railway Cent Hosp Dept Clin Pathol Hangzhou 310000 Zhejiang Provin Peoples R China Zhejiang Univ Sch Med Dept Pathol Hangzhou 310006 Zhejiang Provin Peoples R China

INTRODUCTIONp16 gene (also known as MTS-1, INK4a, CDKN2A), located on chromosome 9p21, is a G1-specific cell-cycle regulatory gene. It is composed of three exons, which encode 156 amino acids[1]. The gene is frequently inactivated in many human cancers. Unlike other tumor-suppressor genes that are commonly inactivated by point mutations, small homozygous deletions and methylation of the promoter represent the major mechanism of p16 gene inactivation[2,3]. In the Western countries, colorectal carcinoma ranks first among malignant tumors. The mortality from colorectal carcinoma has been rapidly growing in China in the last two to three decades. The genetic alterations involved in this tumor are still unclear. Rare mutation and infrequent deletion of p16 gene in primary colorectal carcinoma has been widely reported[4]. There were a few papers on p16 gene methylation in colorectal carcinoma, but the results were contradictory[5,6]. In this study, we have examined a total of 60 samples of colorectal carcinoma and paired 60 samples of the normal colonic mucosa for methylation by means of PCR-based methylation assay. There is infrequent methylation in the promoter of p16 gene both in colorectal carcinoma and normal colonic mucosa. The methylation status in 5′ CpG island of p16 gene in colorectal carcinoma is not related to the clinical pathologic parameters of these tumors.

关键词： Colonic mucosa colorectal neoplasms p16 gene methylation

NONLINEAR FREE SURFACE ACTION WITH AN ARRAY OF VERTICAL CYLINDERS

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Acta Mechanica Sinica 2004年第3期20卷 247-262页

作者： HUANG j.B. Department of Engineering Science University of OxfordUK

Nonlinear diffraction of regular waves by an array of bottom-seated circular cylindersis investigated in frequency domain,based on a Stokes expansion approach.A complete semi-analyticalsolution is developed which allows an efficient evaluation of the second-order potentials in the entirefluid domain,and the wave forces on the *** are derived for the second-orderpotential in the vicinity of individual *** expressions have a simple form,thus providingan effective means for investigating the wave enhancement due to nonlinear interactions with *** on the present method,the wave run-up and free-surface elevations around an arrayof two,three and four cylinders are investigated numerically.

关键词： nonlinear wave diffraction water waves frequency analysis semi-analytical method

A review of energy associated with coal bursts

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International journal of Mining Science and Technology 2018年第5期28卷 755-761页

作者： Winton j.Gale SCT Operations Pty Ltd WollongongNSW 2500Australia

A coal burst is defined as a rapid expulsion of coal(and potentially gas) from the boundary of the roadway. Rock and coal fractures together with micro seismic vibration is a common occurrence during mining, however, it is very uncommon for coal and rock to be propelled into the roadway. Irrespective, such occurrences do occur and appear to require significantly more energy than is available from strain energy release during coal cutting. The sources of energy which can contribute to the propulsion of coal from the face or ribs are typically strain energy from the surrounding ground, seismic energy from a rapid rupture of the ground in the vicinity, or rapid expansion of gas from within the burst source area. The aim of this paper is to briefly review the bursts which may be related to strain energy, seismic energy and gas energy.

关键词： Coal burst Strain energy Gas energy Seismic energy Pillar stability

High-temperature mechanical properties of aluminium alloys reinforced with titanium diboride (TiB_2) particles

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Rare Metals 2011年第2期30卷 200-205页

作者： j.Ooro Ingeniería y Ciencia de los Materiales ETSI IndustrialesUniversidad Politécnica de Madridc/José Gutiérrez Abascal2.28006 MadridSpain

The physical and mechanical properties of metal matrix composites were improved by the addition of reinforcements. The mechanical properties of particulate-reinforced metal-matrix composites based on aluminium alloys （6061 and 7015） at high temperatures were studied. Titanium diboride （TiB2） particles were used as the reinforcement. All the composites were produced by hot extrusion. The tensile properties and fracture characteristics of these materials were investigated at room temperature and at high temperatures to determine their ultimate strength and strain to failure. The fracture surface was analysed by scanning electron microscopy. TiB2 particles provide high stability of the alumin- ium alloys （6061 and 7015） in the fabrication process. An improvement in the mechanical behaviour was achieved by adding TiB2 particles as reinforcement in both the aluminium alloys. Adding TiB2 particles reduces the ductility of the aluminium alloys but does not change the microscopic mode of failure, and the fracture surface exhibits a ductile appearance with dimples formed by coalescence.

关键词： metal-matrix composites aluminium high-temperature properties titanium diboride

SYNTHESIS OF AN EPOXY-TERMINATED HYPERBRANCHED AROMATIC POLYESTER

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Chinese journal of Polymer Science 2002年第6期20卷 585-590页

作者： W.j.Feast IRC in Polymer Science and Technology Durham University South Road Durham DH1 3LE UK

An epoxy-terminated hyperbranched aromatic polyester (P3) was synthesized from a hyperbranched aromatic polyester containing carboxylic acid end groups (P1), which was derived from the condensation polymerization of the AB(2) monomer, 5-acetoxyisophthalic acid. Polymer P1 was converted into the polymeric acid chloride by reaction with thionyl chloride. The acid chloride was reacted with ethanol and glycidol to form a poly(ethyl ester) (P2) and an epoxy terminated material (P3), respectively. The reaction conditions in each step of these processes had to be controlled very carefully to avoid unwanted cross-linking reactions. The characterization of products and intermediates, including molecular weight distributions and thermal properties, are reported.

关键词： hyperbranched polymer hyperbranched aromatic polyester epoxy-terminated hyperbranched aromatic polyester

Heat Transfer Optimization for Air-Mist Cooling between a Stack of Parallel Plates

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journal of Thermal Science 2010年第3期19卷 253-260页

作者： Roy j.Issa Mechanical Engineering Division Department of Engineering and Computer Science West Texas A&M University CanyonTexas 79016USA

A theoretical model is developed to predict the upper limit heat transfer between a stack of parallel plates subject to multiphase cooling by air-mist *** model predicts the optimal separation distance between the plates based on the development of the boundary layers for small and large separation distances,and for dilute mist *** results show the optimal separation distance to be strongly dependent on the liquid-to-air mass flow rate loading ratio,and reach a limit for a critical *** these dilute spray conditions,complete evaporation of the droplets takes *** results also show the optimal separation distance decreases with the increase in the mist flow *** proposed theoretical model shall lead to a better understanding of the design of fins spacing in heat exchangers where multiphase spray cooling is used.

关键词： Air-mist Multiphase Heat transfer Liquid-to-air loading

Plasma-catalysis: Is it just a question of scale?

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Frontiers of Chemical Science and Engineering 2019年第2期13卷 264-273页

作者： j.Christopher Whitehead School of Chemistry The University of ManchesterManchester M13 9PLUK

The issues of describing and understanding the changes in performance that result when a catalyst is placed into plasma are discussed. The different chemical and physical interactions that result and how their combination might produce beneficial results for the plasma-catalytic processing of different gas streams are outlined with particular emphasis being placed on the different range of spatial and temporal scales that must be considered both in experiment and modelling. The focus is on non-thermal plasma where the lack of thermal equilibrium creates a range of temperature scales that must be considered. This contributes in part to a wide range of inhomogeneity in different properties such as species concentrations and electric fields that must be determined experimentally by in situ methods and be incorporated into modelling. It is concluded that plasmacatalysis is best regarded as conventional catalysis perturbed by the presence of a discharge, which modifies its operating conditions, properties and outcomes often in a very localised way. The sometimes used description "plasma-activated catalysis" is an apt one.

关键词： plasma catalysis plasma-activated catalysis non-thermal plasma CO2 conversion