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稀有金属材料与工程 2012年第S1期41卷 52-56页

作者： shum p w Department of Manufacturing Engineering and Engineering Management(MEEM) City University of Hong KongHong KongChina

Increasing demands such as low friction,low wear rate,and long life-time have reached the limits of single DLC *** order to meet the requirements,we propose to use an integrated approach to improve the wear property of an engineering ***,dimples are introduced perpendicular to an engineering surface by a Nd:YAG laser emitting at 1064 ***,solid lubricant DLC is prepared on the patterned surface by magnetron sputtering *** effect of dimple densities from 7%to 45 %on tribological properties of the coating surface was *** wear performance of the textured DLC surfaces was studied by a pin-on-disk reciprocating sliding wear tester under boundary lubrication and dry *** results showed that the DLC coatings with appropriate dimple densities have an obvious improvement on wear performance in term of friction coefficient,wear rate and wear life,as compared to un-textured DLC *** boundary lubrication conditions,the improved wear performance can be explained by the promotion of reservoirs to enhance lubricant retention during *** dry condition,the dimples trap wear particles and leave a free interface between pin and sliding contact surface,and avoid the surface worn by abrasive manner,thereby improving the wear performance of the DLC coating.

关键词： laser wear DLC

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磁控溅射wCu抗菌薄膜的结构与性能

稀有金属材料与工程 2022年第1期51卷 197-202页

作者：王应杰王丽君宁攀梁洛绮沈步云付涛西安交通大学生命科学与技术学院生物医学信息工程教育部重点实验室陕西西安710049 朝日集团有限公司中国香港999077

采用磁控溅射技术在载玻片上制备了钨铜薄膜,研究了薄膜的结构与性能。结果表明,薄膜的沉积速率和铜含量随铜靶电流的增大而升高,晶粒尺寸和显微硬度随铜靶电流的增大而下降。钨铜薄膜形成了固溶体,在铜含量较高时也有铜颗粒析出。wCu... 详细信息

采用磁控溅射技术在载玻片上制备了钨铜薄膜,研究了薄膜的结构与性能。结果表明,薄膜的沉积速率和铜含量随铜靶电流的增大而升高,晶粒尺寸和显微硬度随铜靶电流的增大而下降。钨铜薄膜形成了固溶体,在铜含量较高时也有铜颗粒析出。wCu薄膜具有较高的疏水性,薄膜润湿性、液滴尺寸和环境温湿度都影响水滴和水膜的干燥时间。平板计数和菌液喷雾抗菌实验表明,wCu薄膜对大肠杆菌具有良好的抗菌作用。wCu薄膜有望用于环境设施的抗微生物表面改性。

关键词：薄膜溅射钨铜抗菌

Mechanical Behaviors of Ti-Si-N Coatings Deposited by Bias Sputtering

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稀有金属材料与工程 2012年第S1期41卷 18-23页

作者： p w shum Advanced Coatings Applied Research Laboratory(ACARL) Department of Mechanical and Biomedical Engineering(MBE)City University of Hong KongHong KongChina

Ti-Si-N hard coatings were deposited on steel substrates by reactive unbalanced magnetron sputtering from Ti and Si elemental targets in a mixture of Ar and N2 *** influences of negative bias voltage(in the range of-30 to-80 V)on the mechanical properties of the coatings were *** particular,the critical cycle during dynamic impact tests was employed to indicate the bonding strength of the *** was found that the Ti-Si-N coatings prepared at lower constant bias voltages could effectively improve the adhesion and the cyclic impact performance,but their hardness was dropped significantly to 13 Gpa at a bias of-30 *** bias voltage values induced greater hardness.A maximum hardness of 47 Gpa was obtained at a bias of-60 ***,the coating adhesion was worse in this case,and the number of impact cycles(～8×10 3)that the coatings could endure was much shorter than that of TiN binary coatings(～2×104).On the other hand,the bias voltage was varied linearly from-40 to-60 V during Ti-Si-N *** this circumstance,the hardness of the coatings deposited with the bias-graded configuration remained very high(42 Gpa),and the adhesion strength was improved ***,the critical impact cycle could reach as high as 1.8×***,bias-graded deposition can provide an effective processing route to prepare Ti-Si-N superhard coatings with high adhesion strength and impact resistance.

关键词： Ti-Si-N coatings magnetron sputtering bias voltage mechanical properties impact test

The structure of superabundant semigroups

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Science China Mathematics 2004年第5期47卷 756-771页

作者： K.p.shum 2.Faculty of Science The Chinese University of Hong KongHong KongChina structure theorem for superabundant semigroups in terms of semilattices of normalized Rees matrix semigroups over some cancellative monoids is obtained. This result not only provides a construction method for superabundant semigroups but also generalizes the well-known result of Petrich on completely regular semigroups. Some results obtained by Fountain on abundant semigroups are also extended and strengthened.

A structure theorem for superabundant semigroups in terms of semilattices of normalized Rees matrix semigroups over some cancellative monoids is obtained. This result not only provides a construction method for superabundant semigroups but also generalizes the well-known result of petrich on completely regular semigroups. Some results obtained by Fountain on abundant semigroups are also extended and strengthened.

关键词： superabundant semigroups completely regular semigroups normalized Rees matrix semigroups

SOME REMARKS ON (L)-GREEN’S RELATIONS AND STRONGLY Rpp SEMIGROUpS

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Acta Mathematica Scientia 2011年第4期31卷 1591-1599页

作者：杜兰郭聿琦 K.p. shum Department of Mathematics Ningxia University Department of Mathematics Southwest University Department of Mathematics Hong Kong University

In order to study rpp semigroups, in particular, some special cases, several facts on （l）-Green’s relations and strongly rpp semigroups are given as some remarks.

关键词： (l)-Green’s relations strongly rpp semigroups semilattice congruences Dprimitive idempotents

Correction of CT Burst Array Errors in the Generalized-Lee-RT Spaces

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Acta Mathematica Sinica,English Series 2010年第8期26卷 1475-1484页

作者： Sapna JAIN K.p.shum Department of Mathematics University of Delhi Department of Mathematics The University of Hong Kong

In [Jain, S.： Array codes in the generalized-Lee-RT-pseudo-metric （the GLRTp-metric）, to appear in Algebra Colloq.], Jain introduced a new pseudo-metric on the space Matm×s（Zq）, the module space of all m × s matrices with entries from the finite ring Zq, generalized the classical Lee metric [Lee, C. Y.： Some properties of non-binary error correcting codes. IEEE Trans. Inform. Theory, IT-4, 77- 82 （1958）] and array RT-metric [Rosenbloom, M. Y., Tsfasman, M. A.： Codes for m-metric. prob. Inf. Transm., 33, 45-52 （1997）] and named this pseudo-metric as the Generalized-Lee-RT-pseudo-Metric （or the GLRTp-Metric）. In this paper, we obtain some lower bounds for two-dimensional array codes correcting CT burst array errors [Jain, S.： CT bursts from classical to array coding. Discrete Math., 308-309, 1489-1499 （2008）] with weight constraints under the GLRTp-metric.

关键词： Linear array codes Lee metric RT metric CT burst array errors

On Almost Armendariz Ring

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Algebra Colloquium 2020年第2期27卷 199-212页

作者： Om prakash Sushma Singh K.p.shum Department of Mathematics Indian Institute of Technology Patna PatnaBihar 801106India Department of Mathematics John Fulton Center The Chinese University of Hong KongShatinN.T.Hong KongChina

In this paper,we introduce the notion of an almost Armendariz ring,which is a generalization of an Armendariz ring,and discuss some of its *** has been found that every almost Armendariz ring is weak Armendariz but the converse is not *** prove that a ring R is almost Armendariz if and only if R[x]is almost *** is also shown th at if R/I is an almost Armendariz ring and I is a semicommutative ideal,then H is an almost Armendariz ***,the class of minimal non-commutative almost Armendariz rings is completely determined,up to isomorphism(minimal means having smallest cardinality).

关键词： Armendariz ring almost Armendariz ring weak Armendariz ring lower nil radical reduced ring semicommutative ring

On p-nilpotency and minimal subgroups of finite groups

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Science China Mathematics 2003年第2期46卷 176-186页

作者：郭秀云 K.p.shum Department of Mathematics Shanxi University Department of Mathematics The Chinese University of Hong Kong

we call a subgroup H of a finite group G c-supplemented in G if there exists a subgroup K ofG such that G = HK and H ∩K ≤ core(H). In this paper it is proved that a finite group G is p-nilpotentif G is S4-free and every minimal subgroup of p ∩ GN is c-supplemented in NG(p), and when p = 2 p isquaternion-free, where p is the smallest prime number dividing the order of G, p a Sylow p-subgroup of *** some applications of this result, some known results are generalized.

关键词： p-nilpotent groups, minimal subgroups, formation.

On f-Disjunctive Languages, f-Disjunctive Domains and Solid Codes(Dedicated to the late professor Xu Yonghua (1932-2019))

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Algebra Colloquium 2020年第2期27卷 331-342页

作者： Jing Leng Yuqi Guo K.p.shum School of Mathematics and Statistics Lanzhou University Lanzhou 730000China Institute of Mathematics Yunnan University Kunming 650091China

Every language is either the disjoint union or the intersection of two disjunctive *** family of f-disjunctive languages is a natural generalization of the family of disjunctive *** domains(f-disjunctive domains)are defined as the languages which can be checked whether a given language is disjunctive(f-disjunctive)or *** f-disjunctive domains were first studied by Guo et *** *** continue their study on f-disjunctive *** new results for f-disjunctive domains,containing a relation between disjunctive domains and f-disjunctive domains,are *** this respect,we also make an appropriate opening for the completely dense languages and solid codes.

关键词： f-disjunctive languages f-disjunctive domains completely dense languages solid codes

Novel applications of bipolar single-valued neutrosophic competition graphs

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Applied Mathematics(A Journal of Chinese Universities) 2018年第4期33卷 436-467页

作者： Muhammad Akram Maryam Nasir K.p.shum Department of Mathematics University of the PunjabNew Campus Institute of Mathematics Yunnan University

Bipolar single-valued neutrosophic models are the generalization of bipolar fuzzy models. we first introduce the concept of bipolar single-valued neutrosophic competition graphs. we then, discuss some important propositions related to bipolar single-valued neutrosophic competition graphs. we define bipolar single-valued neutrosophic economic competition graphs and m-step bipolar single-valued neutrosophic economic competition graphs. Further, we describe applications of bipolar single-valued neutrosophic competition graphs in organizational designations and brands competition. Finally, we present our improved methods by algorithms.

关键词： bipolar single-valued neutrosophic digraphs m-step bipolar single-valued neutrosophic economic competition graphs algorithm