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Enhancement of wettability in AZ91/B_(4)C system by a mechanical purification of liquid alloy

Journal of Magnesium and Alloys 2022年第11期10卷 3133-3142页

作者： Artur Kudyba wojciech polkowski Grzegorz Bruzda Adelajda Polkowska Donatella Giuranno Łukasiewicz Research Network-Krakow Institute of Technology Zakopian´ska 73 Str.30-418 KrakówPoland National Research Council of Italy Institute of Condensed Matter Chemistry and Technologies for EnergyVia De Marini 616149GenovaItaly

Mg-based alloys are potential candidate materials for a fabrication of lightweight boron carbide based composites through a reactive melt infiltration approach. In this paper, the effect of a mechanical purification of molten AZ91 alloy’s surface on its wettability with polycrystalline B_(4)C is experimentally evaluated for the first time. For this purpose, sessile drop experiments were performed under the same operating conditions(700℃/5 min;Ar atmosphere), by using both the classical contact heating(CH) and the improved capillary purification(CP) procedure. It was found that the evolution of contact angle values was strongly influenced by the applied procedure. In particular, by using the classical CH procedure, the presence of a native oxide layer on the metal surface hinders the observations of melting process, resulting in a misleading conclusion that the system is non-wettable. Contrarily, during the wetting test performed by applying the CP procedure, the surface oxide layer was mechanically removed by squeezing the molten AZ91 alloy through a capillary. Accordingly, the oxide-free AZ91 drop with a regular and spherical shape was successfully obtained and dispensed on the B_(4)C substrate. A reliable contact angle value of θ =83° was measured at the AZ91/B_(4)C triple line at 700 ℃, which in turn proves that B_(4)C is wetted by the liquid AZ91 alloy. In contradiction to the literature, these good wetting conditions were assisted by a non-reactive wetting mechanism occurring at the AZ91/B_(4)C interface. To succeed in the fabrication of AZ91/B_(4)C composites by liquid metal infiltration, such experimental observations make it reasonable to expect a spontaneous infiltration process exclusively driven by capillarity, which in turn increases the efficiency of the process by the absence of reaction products that could be a potentially detrimental factor.

关键词： AZ91 magnesium alloy Magnesium matrix composites Sessile drop Capillary purification procedure Wettability Contact angle MMCs B_(4)C

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Improved methodological concepts for processing liquid Mg at high temperature

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Journal of Magnesium and Alloys 2021年第1期9卷 183-191页

作者： Artur Kudyba Natalia Sobczak wojciech polkowski Grzegorz Bruzda Adelajda Polkowska Donatella Giuranno Lukasiewicz Research Network-Krakow Institute of Technology Zakopianska 73 Str.30-418 KrakowPoland Institute of Metallurgy and Materials Science Polish Academy of Science25 Reymonta St.30-059 KrakówPoland National Research Council of Italy Institute of Condensed Matter Chemistry and Technologies for EnergyVia De Marini 616149GenovaItaly

In this paper,new improvements of methodological concepts upon examining wettability of high vapor pressure liquid metal systems(***-based alloys)in contact with refractory materials,are presented and *** this regard,high-temperature experiments on molten magnesium(Mg)in contact with graphite as a refractory substrate,were performed by utilizing a newly developed testing device and by applying a suitable experimental *** wetting experiments were carried out by the sessile drop method and under identical testing conditions(700℃/10 min under a protective gas atmosphere).Two different procedures were applied:the classical contact heating(CH)or a newly introduced capillary purification(CP)*** contact angle behaviors observed under the same conditions were strongly influenced by the applied ***,in the case of using the CH procedure,a presence of native surface oxide layer on the metal surface hinders the observations of melting process,making not possible to experimentally determine the wetting kinetics curveθ=f(t).Contrarily,during the wetting test performed on the Mg/graphite couple by applying the CP procedure,the native surface oxide layer was mechanically removed during the squeezing of the molten Mg through the hole of a ***,an oxide-free squeezed Mg-drop with regular and spherical shape was successfully obtained and dispensed on the graphite ***,the reliable contact angle value aroundθ=150°for the Mg/graphite system,was measured within the wetting test.

关键词： Mg-alloys Magnesium matrix composites Sessile drop Capillary purification procedure Wettability Contact angle

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Gastroenterostoma after Billroth antrectomy as a premalignant condition

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World Journal of Gastroenterology 2012年第25期18卷 3201-3206页

作者： Robert Sitarz Ryszard Maciejewski wojciech P polkowski G Johan A Offerhaus Department of Pathology University Medical CentreUtrecht3584 CX UtrechtThe Netherlands Department of Human Anatomy Medical University of Lublin20-950 LublinPoland Department of Surgical Oncology Medical University of Lublin20-081 LublinPoland Department of Pathology Academic Medical Centre 1105 AZ Amsterdam The Netherlands

Gastric stump carcinoma （GSC） following remote gastric surgery is widely recognized as a separate entity within the group of various types of gastric cancer. Gastrecto- my is a well established risk factor for the development of GSC at a long time after the initial surgery. Both exo- as well as endogenous factors appear to be involved in the etiopathogenesis of GSC, such as achlorhydria, hypergastrinemia and biliary reflux, Epstein-Barr virus and Helicobacter pylori infection, atrophic gastritis, and also some polymorphisms in interleukin-l~ and maybe cyclo-oxygenase-2. This review summarizes the litera- ture of GSC, with special reference to reliable early di- agnostics. In particular, dysplasia can be considered as a dependable morphological marker. Therefore, close endoscopic surveillance with multiple biopsies of the gastroenterostomy is recommended. Screening start- ing at 15 years after the initial ulcer surgery can detect tumors at a curable stage. This approach can be ofspecial interest in Eastern European countries, where surgery for benign gastroduodenal ulcers has remained a practice for a much longer time than in Western Eu- rope, and therefore GSC is found with higher frequency.

关键词： Gastric stump cancer Gastrectomy Riskfactors Endoscopic surveillance

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Molecular alterations in gastric cancer with special reference to the early-onset subtype

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World Journal of Gastroenterology 2016年第8期22卷 2460-2474页

作者： Malgorzata Skierucha Anya NA Milne G Johan A Offerhaus wojciech P polkowski Ryszard Maciejewski Robert Sitarz Department of Human Anatomy Medical University of Lublin 20-950 Lublin Poland Department of Pathology Diakonessenhuis 3582 KE Utrecht The Netherlands Department of Pathology H04-312 University Medical Centre Utrecht Post box 85500 3508 GA Utrecht The Netherlands Department of Surgical Oncology Medical University of Lublin 20-081 Lublin Poland Department of Pathology H04-312 University Medical Centre Utrecht Post box 85500 3508 GA Utrecht The Netherlands

Currently, gastric cancer(GC) is one of the most frequently diagnosed neoplasms, with a global burden of 723000 deaths in 2012. It is the third leading cause of cancer-related death worldwide. There are numerous possible factors that stimulate the procarcinogenic activity of important genes. These factors include genetic susceptibility expressed in a singlenucleotide polymorphism, various acquired mutations(chromosomal instability, microsatellite instability, somatic gene mutations, epigenetic alterations) and environmental circumstances(e.g., helicobcter pylori infection, EBV infection, diet, and smoking). Most of the aforementioned pathways overlap, and authors agree that a clear-cut pathway for GC may not exist. Thus, the categorization of carcinogenic events is complicated. Lately, it has been claimed that research on early-onset gastric carcinoma(EOGC) and hereditary GC may contribute towards unravelling some part of the mystery of the GC molecular pattern because young patients are less exposed to environmental carcinogens and because carcinogenesis in this setting may be more dependent on genetic factors. The comparison of various aspects that differ and coexist in EOGCs and conventional GCs might enable scientists to: distinguish which features in the pathway of gastric carcinogenesisare modifiable, discover specific GC markers and identify a specific target. This review provides a summary of the data published thus far concerning the molecular characteristics of GC and highlights the outstanding features of EOGC.

关键词： Gastric cancer Early-onset gastric cancer Molecular alterations Chromosomal instability Single-nucleotide polymorphism Microsatellite instability Epigenetic alterations Loss of heterozygosity

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A Calculus on Granules from Rough Inclusions in Information Systems

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南昌工程学院学报 2006年第2期25卷 22-27,34页

作者： Lech polkowski Polish-Japanese Institute of Information Technology Koszykowa str. 86 02008 Warsaw Poland

Indiscernibility relations induced in information systems in the sense of Pawlak,define granules of knowledge as unions of their equivalence classes,leading to regular structures like Boolean algebras. Apart from Boolean operations on granules, under afixed set of attributes,that induce the partition topology on their collection, one may search for more flexible schemes that would induce in collections of granules some non-trivial topologies and in particular quasi-metrics on granules, allowing for richer structures. A way of realization of this program has been proposed as the paradigm of rough mereology; although abstract, stemming from an alternative set theory, yet it offers a calculus based on kind of quasi-metrics that allows for discussing granules from the point of view of their closeness. In thiswork, we would liketopresent theideas of this approach and basic results with short discussion of applications.

关键词： Granular Computing information systems indiscernibility rough set theory rough inclusions

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Rough Mereology as a Tool for Knowledge Discovery and Reasoning in Intelligent Systems: A Survey

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International Journal of Intelligence Science 2013年第1期3卷 56-68页

作者： Lech polkowski Computer Science Department Polish-Japanese Institute of Information Technology Warszawa Poland

In this work, we present an account of our recent results on applications of rough mereology to problems of 1) knowledge granulation;2) granular preprocessing in knowledge discovery by means of decision rules;3) spati... 详细信息

关键词： Knowledge Engineering Rough Mereology Granular Computing Data Mining Intelligent Robotics

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Toward the inner logic in data： Granular structures as the frame for classifiers

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重庆邮电大学学报（自然科学版） 2008年第3期20卷 335-340页

作者： polkowski Lech Polish Japanese Institllte of IT Warsaw Poland

Any analysis of data collected in data tables aims at revealing the inner logic of data,i.e.,the mechanism of inference which decides about assignment of classes or categories to single items in *** propose to discuss and analyze the mechanism based on granulation of data and the subsequent induction of classifiers from the resulting granular *** consider some logical operators transferred into the realm of data tables and made a basis for granulation heuristics along with classification results inferred from the resulting granular structures.

关键词：数据处理逻辑学粒度粗糙集

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超声内镜检查与螺旋CT用于胃癌局部区域分期的对比研究

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世界核心医学期刊文摘（胃肠病学分册） 2005年第1期1卷 23-24页

作者： polkowski M. Palucki J. Wronska E. 李康 Department of Gastroenterology Med.Center for Postgrad.EducationInstitute of OncologyRoentgena 502-781 WarsawPoland

Background and Study Aims: Endosonography(EUS) has been shown to be more accurate than incremental computed tomography(CT) in the local (T) and regional (N) staging of gastric carcinoma; however, EUS has never been compared with helical CT (HCT). The fifth edition of the TNM classification changed the guidelines for N-staging of gastric carcinoma. The accuracy of imaging methods in this new system remains *** and Methods: Staging accuracy of EUS and HCT were compared prospectively with pathological or intraoperative findings in 88 gastric carcinoma patients. Staging was done according to the fourth and fifth editions of the TNM classification. EUS was done with a radial echo endoscope,and HCT with a scanner with two rows of detectors (two-phase contrast-enhanced scanning of a water-filled stomach). Results:The T-staging accuracy of EUS (63% ,CI 52-73% )was superior to the accuracy of HCT(44% , CI 34-55% ;P=0.021). N-staging accuracy of both methods was similar when the fourth edition of the TNM classification was used (EUS 47% , CI 34-60% ; HCT 52% , CI 38-65% ). However, HCT was more accurate than EUS when the fifth edition of the classification was applied(EUS 30% , CI 18-43% , HCT 47% , CI 34-60% ; P = 0.044).The accuracy of detection of lymph node metastases was similar for both methods (EUS 67 % , CI 54-78% ; HCT 77% , CI 64-86% ). Conclusions: EUS is more accurate than HCT in the T-staging of gastric carcinoma. Both methods are comparable for N-staging, when this is done according to the older, fourth edition of the TNM classification. If the fifth edition is used,EUS is less accurate than HCT.

关键词：超声内镜检查扇形扫描淋巴结转移增强扫描

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